June 3, 2013 • 46 mins
How do batteries work? What are the different types of batteries? Why has battery improvement been so slow? Join Lauren and Jonathan to learn more about the science behind batteries.
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Speaker 1 (00:04):
Get in touch with technology with tex Stuff from how
stuff Works dot Com. Hey everyone, and welcome to tech Stuff.
I'm Jovin Strickland and I'm Lauren Folkebin. Today we're going
to talk about something that we've tackled in a previous
episode at least Chris and I did. We're gonna talk
about batteries and also why have batteries been so slow
(00:25):
to improve over time? What what could be the future
of batteries and uh and what are the implications of that.
This all comes to us courtesy of a listener suggestion.
David via Twitter said, could we talk about the improvements
and battery technology and also why battery text seems to
lag behind other technology when it comes to big leaps.
(00:46):
It's um, that's a good question. And so you know,
it's something that a lot of people have commented on
the fact that you have something called Moore's law. That's
that observation that in general, microprocessors get twice the number
of discrete elements, or if you prefer to think of
it in another way, microprocessors tend to get twice as
powerful every two years or so. There. Yeah, this is
(01:08):
not exponential growth, which I have called it in previous episodes,
by the way, and people right in every time and
call it take us to task on it, which is
important because when we get wrong, it's a misuse of
the word exponential. I'm using it's a colloquial use. But
I do not want to go down that hole again
because I'm like you guys, I get irritated when people
misuse words too. I just wish I didn't do it
(01:30):
as frequently myself. But anyway, it does double every two
years or so, and that's a phenomenal amount of growth.
We're talking about microprocessors that have billions of discrete elements
on them now, and they're all down at the nanoscale.
So there's this amazing amount of technology that's been poured
into microprocessors, partially because Morris law exists and companies strive
(01:53):
to to keep up with it to maintain it because
Moore's law, as we know, is not a real physical law.
It's more of an observation, and companies no one wants
to be the company that comes up and says, yeah,
we can't do that. You know, we just got bored.
So it means that there's been a lot of innovation
in that space. But meanwhile, on the battery front, batteries
have in large part remain more or less the same
(02:17):
for decades. I mean, we've we've seen improvements in battery life,
we've seen improvements in battery efficiency, but there have been
some new technologies over the past fifty years. But even so,
it just hasn't it hasn't at all kept up with
the microprocessors assessor side. This is also, by the way,
this ties into our episodes where we talked about things
(02:38):
like the Singularity, where we talk about how technology doesn't
all progress at the same rate. So while we do
see devices getting more and more sophisticated and powerful, the
power supplies aren't keeping up with that trend. So it
may be that the Singularity, if it is ever going
to arrive, is further off than what some people think,
(03:00):
simply because the power side of the equation is lagging behind, uh,
the the technological sophistication side. So why is that. Well
to understand it, we kind of have to one talk
about what a battery is and to sort of look
at the history of the development of batteries and talk
about what exactly it does now. On a very very
(03:22):
basic level, a battery is something that uses electro chemical
reactions so that you can guide electrons through a circuit
and have it do work. And that's about it. Yeah,
that's that's really all a battery is. And it's because
there are certain chemicals that when they have these reactions,
they lose electrons in the process, and if you are
(03:44):
able to control the flow of those electrons, then you've
got a battery. So batteries date back possibly as long
as though more than two thousand years ago. Yeah, these
these clay jars found in modern day Iraq and you
might might have heard of them called Bagdad batteries, where um, yeah,
clay jars that contained an iron rod and cased in copper.
(04:05):
Tests suggest that the jars were at some point filled
with with with something ascetic like vinegar or wine, and
modern day replicas have successfully created an electric charge. They
might have been used for something like a like any
anything from religious rituals and medicinal purposes to even electro plating. Right,
And if you've seen if you're a big MythBusters fan,
you may have seen an episode where they actually showed
(04:26):
these They created one of these batteries and then they
tried to see if they could get enough of a
charge for it to be detectable. Um, so that that's
an indication of that we were familiar with the fact
that certain materials under certain circumstances could omit this weird energy. Now,
at that time we weren't necessarily really aware of all
the things that could do, but that would change as
(04:48):
the centuries would pass. The next big date I have
is quite some time later, which is and that's when
Alessandro Volta count alis Andra Volta. He's only one. If
there were more than one, I would count them. Oh, sorry,
you're talking about a nobility rank. So count Volta created
(05:11):
a battery by stacking alternating layers of zinc. Lawrence just
checked out at this point zinc, brine, soaked cloth or paper, uh,
and silver. He used these alternating layers kind of a
sandwich here. And we call this a voltaic peel peel
because it's French and uh and and voltaic after volta, yes,
(05:31):
and so uh. The this this peel or pile if
you prefer, because it is a pile. Oh stuff. When
you put it in this this configuration, you start getting
these chemical reactions that emit electrons, and you could make
the stack taller and taller to get more electrons a
stronger flow of current through this peel. But in order
(05:53):
to do that you actually had to stack it up
so high that eventually the weight from the top would
start to squish the layers on the bottom, which would
kind of make the brine soak out, and that would
make it less effective, and also the metal itself would
start to corrode fairly quickly. The Brian and the movement
the electrons, right, it just wasn't wasn't a practical way
(06:15):
of generating electricity, but it showed the premise and it
gave scientists the idea of there's something here, and if
we can figure out other ways of generating the same
kind of energy, we might be able to harness it
for something. Skipping ahead, I mean there there are lots
of different developments in this technology. I have two specific ones.
I think you have a few more. The next really
(06:37):
effective one um was eighty six. Yeah, John Frederick Daniel,
who was an English physicist. He created what we now
call the Daniel cell, which was a you take a
glass jar and on the bottom of the glass jar
you put on in a copper plate. So copper plate
in the bottom of the glass jar, and there's a
wire from the copper plate that comes out of the jar.
(06:59):
Then you or copper sulfate on top of that copper
plate to about the halfway point of the jar. Then
you suspend a zinc plate in the jar, and then
you pour zinc sulfate solution on top of the zinc plate. Now,
zinc sulfate is less dense than copper sulfate, so zinc
(07:20):
sulfate will float on top of copper sulfate. If you've
ever played with liquids of different densities that had different colors,
then you know what I'm talking about. You can see
that actual level of division. Yeah, it's actually it's one
of my favorite things. I just think it's super cool
when it When I see that, I'm easily amused, I
admit it. But anyway, you also have a wire coming
from the zinc plate uh and exiting the jar. So
(07:43):
a wire attached to this would become that that zinc
plate becomes the negative terminal that's where the electrons are
flowing from, and the copper plate becomes the positive terminal
that's where electrons are flowing too. And so if you
were to connect the two wires together, it would very
quickly burn out this bad but if you were to
connect it to a circuit, it could actually do uh,
(08:04):
it could or a load as we call it, it it
could actually do work. So again, not terribly practical, it was.
It was useful for anything that was stationary. But you know,
you're talking about a liquid uh battery here, so it's
not something that you could easily carry around or put
into portable electronics, right right, Yeah, and there's there's a
lot of a lot more elegant ways of getting that
(08:26):
that electrol kind of solution of of you know, just
just a charged molecule then yeah, yeah, And it wouldn't
be until we developed dry cell battery technology that we
started to find practical ways of using it in portable means,
you know. And even then, you know, the batteries weren't
small enough to use and what we consider portable electronics today,
but you could move it around. Uh. The kind of
(08:48):
Daniel cells that that John Frederick Daniel created were useful
for different technologies, things like telephones. It was stuff that
back then you did not carry around. I don't know
if your kids know this, but telephones used to be
these things that were extremely stationary. It's only recently that
we started carrying them around. Uh. Anyway, that's the kind
(09:10):
of battery that became popular for that. Uh. Now, did
you have any other ones who want to talk about
before we move onto the basics of batteries rechargeable batteries.
The signs for that started um started with research around
eighteen fifty or so when a French physicist, Gaston Plant
invented the lead acid cell um and that that was
a that was a precursor to to modern day car batteries.
(09:33):
So there you have, you know, the discovery that this
chemical reaction that takes place within a battery, you get
compounds that form out of it, and it makes the
battery over time less effective. That's why batteries die. Eventually,
the active elements that would create the flow of electrons
end up combining with other stuff and for the purposes
(09:53):
of an of passing a current through a circuit, they
become a nert. Yeah. Yeah, something either wears out or
um or maybe the the anodeor cathode could could dissolve
in the solution. Right you just essentially what it means
is that you run out of the stuff you need
in order to make it to make this go right?
And so what what was it? Plant? Believe? Yes, what
(10:17):
Plant discovered was that for some kinds of solutions, if
you were to pass electric current through the system as
opposed to siphoning it off, you could reverse this process
and yeah, and create a battery that can be used
more than once. Right now, this does not work for
all batteries, which is why you can't just throw any
(10:38):
regular battery into a recharger and expect it to come
out fine. If you did that to a to a
you know, to Adris cell or something like that, mostly
just explode, right. Yeah, that these are has to be
batteries that are using specific uh compounds in it for
it to have this this reversible reaction, because not all
compounds will reverse some of them once they're done, they're
(10:59):
done and battery. We will talk about that a little
bit a little bit later. Um, but but let's let's
talk about how how exactly this this circuitry works. Okay, So,
if you've ever looked at a battery, you've seen that
there's a side that is labeled as a plus and
one that's labeled as a minus, so positive and negative.
If you're looking at like a nine volt battery, then
they're next to each other. If you're looking at double
(11:20):
a's or whatever, then it's on one end and the other.
So the negative end the that's where the electrons flow
out of. That's the electrons flow from that end through
a circuit and into the positive end. Uh. Now we
know that, you know, the the opposite charges attract, So
that's why the negative wants to get to the positive.
(11:41):
And inside the the the battery itself, there is a
chemical called or a compound called an electro light. Now
the electro light has a very important job. It blocks
those electrons from just passing from the negative side to
the positive side directly. Direct That would burn burn everything out. Yeah,
that you wouldn't You wouldn't be able to power anything.
(12:01):
The battery would just you would just have a chemical
reaction inside a canister and it would be dead within
however long it took for those reactions. Yeah. Um. So
it does allow ions to pass through, but not electrons,
and that becomes important. So the negative terminal is connected
to something that's called the anode. The positive terminal is
(12:23):
connected to what we call the cathode, and these together
are the electrodes of a battery. Then you've got the
separator between the anode and the cathode that's presenting that's
preventing those two sides from reacting to each other. And
you have the electro LTE that allows the electric charge
to flow between cathode and anode, allowing the ions to
pass through while making sure the electrons don't. And then
(12:44):
you have a collector, which is the part of the
battery that conducts the charge to the outside of the
battery and through whatever the load is, the electronic load,
so the circuit um. So within that anode side, the
negative side, the chemical reaction that takes place is called
oxid ation. It's an oxidation reaction. This ends up releasing
ions and the ions move through the electro light to
(13:06):
combine on UH the other side, and then you've got
UH the release of electrons that go through the circuitry.
On the catholic side, you've got the reduction reaction. That's
where the catholic material and the ions UH combined with
the electrons that are coming in through the circuit that
(13:27):
they form a new compound. And so essentially you've got
the anode freeing up electrons. The cathode accepting electrons, and
the electrons do work along the way. So if you
were to actually connect a wire from the negative terminal
to the positive terminal, you would allow that that pathway
to be open and it would just start to burn
up that battery pretty quickly. Don't do that. It's a
(13:52):
waste of batteries. It's going to heat up that wire.
It doesn't do anything other than kill your battery. But
but that's what happens. It's so when you've got it
plugged into something, whenever you turn the switch on to
whatever it is, whether it's a you know, a lightsaber
or a phaser. You know, I allow all kinds of
science fiction toys for batteries. But whenever you turn it on,
(14:15):
it opens up that circuit and that allows the electrons
to flow through. And when you turn it off, then
the one of the gates gets closed essentially, and you
no longer the connection is no longer there, so the
battery stops the chemical reaction. It has to have that
pathway open for the chemical reaction to keep going. Now,
there are several different basic types of batteries that are
(14:37):
out there, and we're just going to cover a couple
of them, and we're covering them based upon the stuff
that's inside them, right, because there's a whole bunch of
different substances that you can use to create these reactions.
Like like we said, so yeah, so so one basic
type is the is alkaline batteries. Uh, the anode and
alkaline batteries tends to be zinc powder. So the anode
(14:58):
again is that negative side that's the electrons are coming from.
The cathode side has typically manganese dioxide, and the electrolyte
is typically potassium hydroxide. These are the kind of batteries
that you typically find in double a's, C and D batteries. Right.
These are all examples of this is an example of
dry cell batteries. Yes, which dry cell batteries. One of
(15:20):
the big benefits of those that you don't have to
worry about liquid slashing around inside the battery, so that
allows it to be used in lots of applications. You know,
anything that's liquid obviously you can't shake around too much
or else just gonna disrupt it and you're not gonna
have a working battery. For they're more they're more more volatile. Yeah,
you want that, you want then a very h stationary position.
(15:41):
Then you've got zinc carbon batteries. Uh. These have an
anode that has that's zinc obviously. Uh. And then you've
got the meganese dioxide cathode. But the electrolyte in this
case is often either ammonium chloride or zinc chloride. These
are often found in triple A, double A, C and
D dry cell batteries. Then you've got lithium ion batteries.
These are the ones that we find in laptops, smartphones, cameras,
(16:05):
that kind of stuff. They are rechargeable batteries and they
have different materials in them. But uh, one common version
of lithium ion batteries uses a carbon note and a
lithium cobalt oxide cathode and uh and yeah, these are
the ones that we use when we're recharging our our
various electronics very frequently anyway. Then you've got lead acid batteries.
(16:29):
These are the ones that you often find in cars.
These are more heavy duty, right, they are more volatile.
They do include liquid, Yeah, they include their they're they're
electrolyte tends to be sulfuric acid. This is one of
the reasons why you want to be really careful with
car batteries because the materials inside them can be very
caustic and and they can damage you your stuff, your car.
(16:51):
That's why you know you've got to be really careful
with these things. Um, they tend to have uh, lead
dioxide and metallic lead as their electrodes. So yeah, the
rechargeable battery we've already talked about, that's the kind where
if you put the electric current through the battery, you
reverse this uh, this chemical reaction. Uh. It depends upon
(17:13):
what that rechargeable battery is made from, whether how effective
this this process is right, because there's some kinds of
rechargeable batteries that have well they have a memory, and
that memory is not a good one. The memory effect
is what I'm talking about. So I don't know how
many of you are familiar with this, but if you've
(17:36):
ever heard someone say that before you recharge your device,
you should make sure that it's completely that the current
charges completely out. This was due to some some older
types of batteries that have been mostly replaced by lithium
ion batteries. Nickel cadmium is the main culprit here. So
the problem that some people notice with nickel cadmium is
(17:59):
that if you used a nickel cadmium battery for a
while and then you recharged it before you had completely
discharged the original charge, it wouldn't hold as much of
a charge the next time. So let's say that I've
got a device that has a nickel cadmium battery in
it and I run it down to about left like
it's it only has charge left, and I decided to
(18:21):
recharge it. Well, now it's new maximum charge is more
like eight of what it used to be because I
didn't let it go. It remembers that, but it doesn't
let me actually consume that power anymore. So yeah, that
was a problem. Now most batteries now don't have that issue.
(18:41):
I mean, there's still a minor memory effect in some
rechargeable batteries, but it's not nearly as dramatic as it
the older batteries were, right, So so yeah, so if
you are using a lithium ion battery and someone tells
you that thing, you can you can tell them that
we told you no, No, not as big a deal.
And another interesting thing about batteries is what happens if
(19:02):
you place them in series versus in parallel. So in
series it sounds kind of you know, is what it is.
You've you've got them hooked up so that they are
all the charges running through one and then another and
then another. Yeah, in a sequence exactly. And uh, if
you do that, you increase the voltage of the output. Now,
(19:22):
if you put them in parallel, you increase the current.
Now you might wonder what's the differences voltage and current
if you're if you're not really familiar with electronics. I
always have to look this up because I I I,
I always second guess myself. But voltage measures the energy
per unit charge. And you can think of that is
it's how strong the electrons are pushed through a circuit.
(19:45):
So think of it like water pressure, you know, through
a hose. So the greater the water pressure, the harder
that water is being pushed through the hose. That's essentially
your voltage, it's you know. And then current is the
rate at which electric charge passes through a circuit. Now,
voltage will stay constant, the voltage output will stay constant
based upon whatever kind of battery you have, or whether
(20:07):
or not they're in series. Uh, but otherwise it's going
to remain the same current, however, will vary depending upon
the load you place it, uh, you place on it,
so and that can like the resistance of a wire
can affect what the current is. So current is variable.
(20:28):
Voltage is not, and uh, apart from the fact that
if you put them in series, you increase the voltage,
but once you've done that, it does not vary. Um.
All right, Well that's the basis the very basic foundation
of batteries. And in the moment we're going to talk
about why we haven't moved very far away from this
(20:50):
basic explanation we just gave you. But before we do that,
I'd like to take a quick moment to thank our
sponsored all Right, so we're back, uh, and we've learned
the basic function of a battery and how it does
what it does. So what's the problem. Why haven't we
made super batteries that last forever and never need to
(21:10):
be recharged and can put out more energy than uh
the generator? Yeah, well, I mean, you know, there's the
first commercial dry cell batteries premiered in and they haven't
really changed all that much since then. Yeah, We've we've
experimented with different materials, but the actual process has remained
(21:31):
very much the same, And there are physical limits that
chemical batteries have. They can only generate so much electricity
through these reactions. There have been a few permutations of
different things. In addition to those nickel cadmium batteries that
that have the memory effect problem that we mentioned earlier,
there's there was also some some nickel metal hydride, but
(21:53):
they had a really short shelf life. They would start
degrading pretty quickly. Yeah, that's another thing about some types
of batteries that lithium ion batteries have that problem as well. Um,
they're they're less bad at it, but they're still not ideal. Right,
the idea being that these these chemical reactions, like the
longer the battery sits idle, the less juice. Yeah. And
(22:15):
and and this doesn't have anything to do with how
much you use it. It's it's from the moment that
they're made. Yeah. Yeah. And also you may have heard
stories about, well, if you want to keep your batteries
from degrading, you should put them in the refrigerator. Don't
do that. Don't do that because that actually it actually
slows down the chemical processes that happen when you yeah,
(22:37):
when you're when you're trying to use the battery, and
you're going to not get as much juice as you
thought you were because the chemicals themselves are too cold
to have those chemical reactions happen at the correct rate.
They're still going to happen, but you're gonna get a
easily amount of juice out of it, right. So, so far,
lithium ion batteries, especially for small uses, have have been
(22:57):
have been pretty pretty rad um. How however, they are
very sensitive to high temperatures um, you know, which is
occasionally why they wind up exploding, bursting into flame. Let's
let's also point out that lithium is an alkali metal,
so and we'll we'll talk about a little bit. We're
gonna talk about a AH, a possible future type of
(23:19):
battery that people are working on right now, where that's
really an issue. Both lithium and sodium are being considered
for new types of batteries, but both of them are
alkali metals. The big problem, there are several problems, but
the big problem I would say with that is alkali
metals belong to a class where they tend to be
(23:39):
let's say, reactive when they come into contact with water.
So if you've ever heard stories about sodium and water,
or if you've ever seen anyone demonstrate what happens when
sodium encounters water, uh, you know it's explosive. The same
thing is true of lithium. All right, this is where
we get a little chemistry. Lesson, everyone, go and get
your period audic table of elements. I'll wait now. If
(24:03):
you look at the left hand side of that table
of elements, you're gonna see that down the line you're
gonna have lithium and you're gonna have sodium that are
both in that same line, as well as potassium and
some other alkali metals. That means that those elements share
common characteristics, and one of those is when water comes
in contacts, sometimes things go boom. So first of all,
(24:25):
never never ever play with these I don't if you
get hold of sodium or lithium, never play with that
and water. This is seriously dangerous stuff. Also, probably just
just don't. I mean, because because water is in the
air around us in in great enough quantities that hypothetically
it can burst into flame. I know of someone I didn't.
(24:47):
This is a friend of a friend's story, so it's
possibly apocryphal. So it could be urban legend. I admit that,
But I know of someone who pocketed some sodium from
his chemistry class and then was walking around with it
in his pocket, and his body was giving off moisture,
(25:10):
and so he began to feel a burning sensation in
his pants and immediately ran to the bathroom and pulled
the sodium mountain threw it into the toilet, which then exploded. Yeah, again,
could be apocryphal. This is it was a story about
a high school student who went to a rival school,
so it could have very well been one of those
stories where ha ha, the people who go to that
(25:31):
school are so dumb, so much more dumb than the
people who go to my school, which is saying something.
I'm just kidding. I love all my classmates Spartans, but anyway,
you were the Spartans, I was the Spartans. Were Spartans
Spartans together. This is tech stuff. So but the point,
the point being that these these these elements have serious
(25:53):
drawbacks to him. And that's one of the reasons why
the another reason why battery improvement has gone so slowly,
because we have to find safe ways to handle this
stuff so that it doesn't come into contact with water
and then just blow up. Right. Part of that in
lithium ion batteries specifically, is that they have to have
a very small, very simple onboard computer to to manage
the way that all of the bits flow around in there,
(26:16):
and uh and and that that makes them pretty expensive.
Lithium is already pretty expensive, but it makes them even
more expensive than they would already be. Now, we have
seen some improvements with battery life in recent years, but
a lot of that doesn't come from improvements in the batteries.
It's coming in improvements in the actual electronics. We are
finding more efficient ways to generate the stuff we want.
(26:37):
So your smartphones, if you've got a smartphone recently that
has a decent battery life, it may not be that
the battery is so much better. It's just that the
people who designed the hardware and software we're able to
maximize performance while being as efficient as possible. So you're
still working with the same basic amount of Yeah, but
(27:00):
you don't need as much of it to do the
stuff you are doing exactly. Speaking of that juice, though,
the problem with batteries, and the reason that that that
gasoline has not been ousted completely by batteries. Is that
gasoline has an energy density of something like thirteen thousand
watt hours per kilogram, which is which is just a
measure of how much of juice it has, how much
(27:20):
how much, how much work they can get out of
a given amount of gasoline. Sure, um, the best lithium
ion batteries only hold about two hundred what hours per kilogram,
so with of a of a hypothetical in a perfect
world situation, four hundred possible, So still vastly underpowered when
you compare it to gasoline. Right now, there are some
(27:45):
people out there, very very smart people working on batteries
that would have much higher densities power densities for their
batteries if they can get the batteries to work, if
they can get the the components to to to play nicely,
to not explore oade, and to work on larger scales,
and to work after more than three charges. There are
a lot of barriers that are in place, and we'll
(28:08):
talk about some specific uh cases, but keep in mind
there have been dozens, if not hundreds of different experiments
and trying to improve battery technology, and most of them
just have not panned out. They might have seen promising
at the beginning, but when you get to a point
where you're thinking, all right, how are we going to
scale this up where we can actually manufacture it or
(28:29):
create a battery large enough to do something useful, and
then things start to break down. So one of the
ones I wanted to talk about where these things called
micro batteries, And this was something that that we received
from that initial request to talk about battery improvements. And
this is a story about a team of researchers from
(28:50):
the University of Illinois uh talking about a particular type
of battery that uses these very tiny electrodes and lots
and lots of them, and their three dimensional electrodes, and
it was almost like these electrodes are kind of intertwined together,
so they're very close together, which allows the ions to
pass very very quickly. It also allows electrons to flow
(29:14):
very quickly, and the idea being that you would be
able to release quite a bit of energy in a
short amount of time, faster than you could with most batteries,
and you could also recharge the battery way faster, right,
because that thoroughput speed has a lot to do with
how effective a battery is. Yeah, and in fact, according
to several articles that were posted about this technology. BBC
(29:36):
did one as well as some other outlets. The claim
was that such a battery would be reached could be
recharged one thousand times faster than competing technology, so you
could turn your you know, plug your smartphone in. Let's
say your smartphone has one of these batteries in it
and you plugged it in. After a second, it's fully recharged.
(29:57):
You don't have to leave it there for hours for
it to charge, which is that's a very attractive thing.
So you're thinking, well, if it can release lots of energy,
and if it can be recharged in a blink of
an eye, where's the problem. Well, mostly the problem comes
in from the manufacturing side and the scalability as well
(30:18):
as uh the fact that it's not the most reliable technology.
Ours Technica actually ran a great article where they really
looked into this and and dove deeper than a lot
of the other outlets did to kind of take a
look at this technology with a skeptical eye, just to
make sure that it really did measure up to the hype,
(30:38):
because we've seen this before with battery technology, right, and
this isn't to say that they want the team won't
figure out a way of of solving the problems that
they face. But here are some of the problems. One
of them is that it's really hard to manufacture these things.
The way that the team was doing it, they were
using this uh, this essentially gold to make these little
three dimensional um electrides electrodes sort of, and then they
(31:02):
used poly styrene uh, little little tiny poly styrene pills,
essentially packing them in there, twisting the electrodes around, coding
it and nickel in a well in a combination of
nickel and tin and then UH nickelton alloy actually, and
then coding the rest of it with manganese oxy hydroxide uh,
(31:26):
and then melting away the poly styrene so it it's gone,
then immersing the whole thing to a liquid that was
heated to three degrees celsius or five degrees fahrenheit. And
so it's what even the team has referred to as
a boutique manufacturing approach, meaning that it's very detailed, it's painstaking,
(31:48):
it is not automated, extremely expensive. Yeah, it's no time
consuming exactly, not something that's scalable to mass manufacturing methods
right now, certainly right that's not to say that they
wouldn't find some other way of doing it. They may
find a way of doing it where it doesn't require
this series of painstaking steps in order to get the
result that they want, but uh, it's not ideal. Another
(32:12):
problem is that the electrolyte they're using is combustible, so
that's always a concern. If you get it too hot,
it could burst into flames. Uh um, or you know,
if you were to get it close to a flame,
it could catch fire. And on top of all that, uh,
the battery loses about five percent of its capacity with
each charge discharge cycle, so after fifteen cycles it would
(32:35):
be down to about two thirds of its original capacity.
And uh, if you were to do a full discharge
full charge, it might be even worse than that. So
while it would recharge very quickly, it would have a
little less juice each time. And so after you recharge
it twenty times, yeah, you have to buy a new battery,
(32:57):
new battery, right, So, uh, that raises lots of problems
to waste problems. For example, like even if you were
to say, well, that's acceptable because I want to be
able to charge my phone in the second, you can
do that twenty times, and then you have to go
buy a new battery. And especially when the when the
technology to create it is so so detailed and expensive,
and to be fair, you wouldn't even you wouldn't even
go twenty times, right because each time you would have
(33:20):
less juice and so your your phone would be less
and less useful over time. So after after your phone
doesn't last more than a couple of hours, you think, well,
I gotta get a new battery. So that might be
six or seven recharges, depending upon how hard you are
on electronics. If you're me, then you'd be like, all right,
recharge it, give me a new battery. So um. So
(33:42):
that that's the downside to this micro battery technology. That's
not to say again that they won't find ways around that.
Engineers are brilliant at finding ways of fixing problems. But
it's not going to be the revolutionary battery technology that
we're all going to see in our smart on in
the next few months. It'll it'll at least be a
couple of years before we can see this rolled out
(34:05):
in any way, assuming that they find a way to
fix these problems. Right. One of the other ones that
I wanted to talk about our lithium air batteries, and
this is where we're getting into those alkali metals and
the concern about how they react with water exactly. You know,
they could hypothetically store up to four times as as
much as as lithium ion batteries, as much power as
(34:26):
lithium ion batteries, but they work in that um. Lithium
combines with with oxygen that's trapped by a carbon surface.
Carbon nanotubes are are popular right now and um and
the resulting interplay of these lithium ions and electrons induces
the flow of current. UM. Yeah, you get a get a.
One of the by products you get out of this
(34:47):
is lithium peroxide, which is a problem because as it accumulates,
it starts to make it more difficult to recharge the battery. Right.
So they they've only recently figured well, they they've had
a bunch of of barriers to to making this work.
That is, that is one of them they're they're starting
(35:08):
to For a long time, they didn't understand why the
electrochemical reactions were going so poorly in these things, and
it wasn't until uh May thirteen that that researchers at
m I T and Sandia National Labs announced that they
were starting to be able to observe the reactions at
all to figure out why this isn't working, and that's
when they started seeing this lithium peroxide forming that was
(35:31):
inhibiting the flow of electricity. And uh, they did discover
that if the electricity were flowing, that the lithium peroxide
was starting to reduce around the trouble spots. And they
figured that if they could improve the electron flow of
the battery overall, then they might be able to get
around this problem so that recharging doesn't become an issue. Right. Uh,
(35:55):
that that explosion thing that we mentioned earlier is still
at issue because when when you're dealing with you know,
these these carbon surfaces are allowing air to basically breathe
into the battery, and since water happens in air, Yeah,
you have to find either a way of coating the
lithium inside the battery so that the water would not
react with the surface of lithium, or you'd have to
(36:16):
find a way of filtering the water out entirely, so
that membrane at the top end, yeah, hydrophobic membrane, that's
what we'd like to call that it's scared of water.
It pushes water out, So uh yeah, it's that that's
an issue. Now, there is a potential alternative to lithium
air batteries called sodium air batteries that are even they
(36:38):
are they may not be able to hold as much
energy as a lithium a battery. It's a lower theoretical
energy density but a higher practical energy density at the
current moment exactly, so current moment. So yeah, no, it's
it always happens. You can't get around it. But yeah,
that's so that's a stability. But again, remember sodium is
(37:01):
probably that alkali metal groups, so against same issues. You
get that water in contact with sodium and battery goal
boom instead of instead of zap zap. Right. Uh. There's
there's also research being done into what's being called solid
state batteries UM, which are kind of kind of the
lithium ion um solution to dry cell batteries. It's it's
(37:24):
using um thin layers of solid electrolyte instead of instead
of the liquid that most lithium ions use. Yeah, and
then there's a I read on Wired this interesting idea
of spray can batteries where each of the each of
the elements that you would find within a battery, the cathodeiana,
the electrolyte, all that is represented by a different can
(37:46):
of uh sprayable material. So you could actually spray this
material onto different surfaces and make a battery that way.
And the idea being that this would allow you to
create batteries in devices that would break the battery designed
directly into the device, so you wouldn't have this blocky
battery compartment. Now, it's not saying that these batteries would
(38:07):
be particularly efficient or powerful compared to what we have now,
just that this would give us more opportunity to explore
different ways of shaping batteries so that they are part
of our electronics and not just you know, again, not
just some clunky thing that you have to find make room,
make room for it, right, right, and and also not
(38:28):
so heavy, um what would be terrific. That reminds me
of the nanocomposite paper batteries that some people are are
working on. These are these are composed of cellulose and
um an aligned carbon nanotubes woven together um and and
they're they're they're small, they're flat, they're flexible, they're implantable. Um,
they could hypothetically be put into medical devices. Yeah, these
(38:50):
could actually use biological fluid as ionic fluid. So it
ends up turning your body's fluids into the electrolyteed needs.
This is just making think of idiocracy. It's electrolyte. It's
the thing that plants crave um. I was doing the
hand gesture and everything for those of you are fans
of that movie. Then there's also uh, you know, the
(39:10):
Verge reported on bacteria that are able to transfer electricity,
and scientists had known about this for a while, but
they weren't sure about what the mechanism was, like how
did it transfer electricity? And they discovered that that there
were proteins on the bacteria surface that we're responsible for
electron transfer. Uh. The bacteria is uh, this is this
(39:35):
is going to be a train wreck of a pronunciation
of me luck she wa nella oneidnisis. But anyway attaches
to rusty iron and other materials and breaks those down
and in the process of breaking down these materials, it
releases electrons. So why are we interested in this? Because
(39:57):
by studying biological organisms that can emit electricity as part
of some process where it's consuming something, we might be
able to create biological batteries, and these are these are
a little bit more of fuel cell really than a battery.
But and and to explain the difference, a fuel cell
(40:17):
is a device that you put fuel into and then
there's a chemical reaction that generates electricity, and then you
refill the fuel cells. So and you know, with a battery,
what you're doing is you're using an electric uh or
electrochemical reaction to harness electricity, and then you either have
to reverse the reaction in order to get the battery
(40:39):
to do it again, or you have to replace the battery.
Fuel cell, you just refill it with fuel. So hydrogen
fuel cells are the ones that most people know about
because those the ones that we've talked about for things
like cars. Hydrogen fuel cells use hydrogen, which is the
most plentiful element on Earth, although you have to break
it up from other stuff. It doesn't it doesn't it's
(41:01):
not so plentiful in its pure state. It's usually it's
it's in water, which is very plentiful, and hydrocarbons as well,
also very plentiful. But you have to separate the hydrogen outfast,
which requires energy a lot of energy. But once you've
got it, assuming that you've assuming that you found some
sort of hydrogen mine where it's not going to take
you too much energy to get it free. Um, you
(41:23):
put hydrogen on one side of a membrane um that
has a catalyst on it, usually something really expensive like platinum,
and then on the other side of the membrane you've
got oxygen. The membrane allows the hydrogen ions to pass through,
but not hydrogen atoms. It has to lose the electrons
for it to pass through. The electrons go through a
(41:43):
circuit just like it would with a battery and combine
on the other side. So the hydrogen ions passed through
the membrane and that meets up with the oxygen and says, hey,
you wanna you wanna go do something? I got my
buddy here, my buddy here, and I would love to
take you out to dinner. And so the two hydrogen
take out the one oxygen to dinner. Meanwhile, the electrons
come back over through the circuit and recombined, and then
(42:06):
you get water. So the output of a hydrogen based
fuel cell is water, electricity, and heat, which is why
every pretty sweet deal. Yeah, I think This is why
we would love to use it to fuel cars because
instead of giving off all these different greenhouse Yeah, now,
water vapor is technically a greenhouse gas, but it's water vapor.
(42:28):
It's not carbon dioxide, it's not methane or anything like that.
So that's why they're very attractive. But they are you know,
they're similar to batteries, but there there is a difference.
There is I do I do have a have a
bio battery that I was just reading about research last
November at m i T. Harvard and the Massachusetts Eye
and Ear Infirmary. Um the okay, so, so mammals have
(42:53):
in their inner ears chamber that's filled with ions and
um uh. These these ions produce use an electrical potential
which drives neural signals. And what this means is that
this is the chamber in your ear that that lets
the vibration of your ear drum be converted into an
electrochemical signal that your brain can read and then interprets
(43:15):
the sound and interprets a sound. Um and so but
but but you've got this this inner chamber that's just
hanging out with ions in it, which is a potential battery.
Um and these researchers put UM put some electrodes in
there along with a very low power electronic device, and
UM the chamber produced enough power with these electrodes to
(43:38):
power the device to wire wirelessly transmit data. That's pretty
cool to to an external drive. Now again we're talking
about you know, we're not talking about stuff that's that's
advancing the power of batteries, but we are looking at
brand new applications that could that are really exciting. Yeah,
it's just but again, this isn't the thing that's going
to make your cell phone last longer. Probably probably not.
(44:02):
It's it's really really really low power, but it would
it would mostly be great for for medical advances in
um hearing aids. Yeah. So anyway, anyway, the advances we're
talking about, for the most part, are again just refining
the technology that we already have. It may turn out
that we just have to find a different means of
(44:23):
generating electricity that goes away from this electrochemical model entirely
for us to get beyond this this bottleneck, or if
one of these other like the if the lithium air
or sodium ayor batteries work out, or if the micro
battery works out, maybe maybe that will be that that
would be a huge leap ahead, and if either of
those of any of those were any any more efficient
(44:45):
chemical combination. Right, So there, we're not saying it's impossible.
We're just saying that it's been several decades and we've
only seen incremental improvements. So don't be surprised if that
stays the same. If it doesn't stay the same, aime,
if we do have this huge leap, that's gonna be
awesome for everybody, and that's what everyone wants. Just you know,
(45:07):
be prepared to wait. Just what I'm saying, all right,
So I think that was a good explanation of batteries,
also what the future is and why it's kind of
lagging behind at least in respect to the way processors
are taking off. If you guys have any ideas for
future episodes, there's a concept you really want to explained,
or there's a particular gadget or computer that you think
(45:29):
needs to be talked about, or there's a company or
a person let us know, send us an email that
address is tech stuff at Discovery dot com, or drop
us a line on Facebook or Twitter. Are handled. There
is text stuff HS w and Lauren and I will
taught to you again really soon For more on this
(45:54):
and thousands of other topics. Does it, How staff works?
Dot com chos
Get in touch with technology with tex Stuff from how
stuff Works dot Com. Hey everyone, and welcome to tech Stuff.
I'm Jovin Strickland and I'm Lauren Folkebin. Today we're going
to talk about something that we've tackled in a previous
episode at least Chris and I did. We're gonna talk
about batteries and also why have batteries been so slow
(00:25):
to improve over time? What what could be the future
of batteries and uh and what are the implications of that.
This all comes to us courtesy of a listener suggestion.
David via Twitter said, could we talk about the improvements
and battery technology and also why battery text seems to
lag behind other technology when it comes to big leaps.
(00:46):
It's um, that's a good question. And so you know,
it's something that a lot of people have commented on
the fact that you have something called Moore's law. That's
that observation that in general, microprocessors get twice the number
of discrete elements, or if you prefer to think of
it in another way, microprocessors tend to get twice as
powerful every two years or so. There. Yeah, this is
(01:08):
not exponential growth, which I have called it in previous episodes,
by the way, and people right in every time and
call it take us to task on it, which is
important because when we get wrong, it's a misuse of
the word exponential. I'm using it's a colloquial use. But
I do not want to go down that hole again
because I'm like you guys, I get irritated when people
misuse words too. I just wish I didn't do it
(01:30):
as frequently myself. But anyway, it does double every two
years or so, and that's a phenomenal amount of growth.
We're talking about microprocessors that have billions of discrete elements
on them now, and they're all down at the nanoscale.
So there's this amazing amount of technology that's been poured
into microprocessors, partially because Morris law exists and companies strive
(01:53):
to to keep up with it to maintain it because
Moore's law, as we know, is not a real physical law.
It's more of an observation, and companies no one wants
to be the company that comes up and says, yeah,
we can't do that. You know, we just got bored.
So it means that there's been a lot of innovation
in that space. But meanwhile, on the battery front, batteries
have in large part remain more or less the same
(02:17):
for decades. I mean, we've we've seen improvements in battery life,
we've seen improvements in battery efficiency, but there have been
some new technologies over the past fifty years. But even so,
it just hasn't it hasn't at all kept up with
the microprocessors assessor side. This is also, by the way,
this ties into our episodes where we talked about things
(02:38):
like the Singularity, where we talk about how technology doesn't
all progress at the same rate. So while we do
see devices getting more and more sophisticated and powerful, the
power supplies aren't keeping up with that trend. So it
may be that the Singularity, if it is ever going
to arrive, is further off than what some people think,
(03:00):
simply because the power side of the equation is lagging behind, uh,
the the technological sophistication side. So why is that. Well
to understand it, we kind of have to one talk
about what a battery is and to sort of look
at the history of the development of batteries and talk
about what exactly it does now. On a very very
(03:22):
basic level, a battery is something that uses electro chemical
reactions so that you can guide electrons through a circuit
and have it do work. And that's about it. Yeah,
that's that's really all a battery is. And it's because
there are certain chemicals that when they have these reactions,
they lose electrons in the process, and if you are
(03:44):
able to control the flow of those electrons, then you've
got a battery. So batteries date back possibly as long
as though more than two thousand years ago. Yeah, these
these clay jars found in modern day Iraq and you
might might have heard of them called Bagdad batteries, where um, yeah,
clay jars that contained an iron rod and cased in copper.
(04:05):
Tests suggest that the jars were at some point filled
with with with something ascetic like vinegar or wine, and
modern day replicas have successfully created an electric charge. They
might have been used for something like a like any
anything from religious rituals and medicinal purposes to even electro plating. Right,
And if you've seen if you're a big MythBusters fan,
you may have seen an episode where they actually showed
(04:26):
these They created one of these batteries and then they
tried to see if they could get enough of a
charge for it to be detectable. Um, so that that's
an indication of that we were familiar with the fact
that certain materials under certain circumstances could omit this weird energy. Now,
at that time we weren't necessarily really aware of all
the things that could do, but that would change as
(04:48):
the centuries would pass. The next big date I have
is quite some time later, which is and that's when
Alessandro Volta count alis Andra Volta. He's only one. If
there were more than one, I would count them. Oh, sorry,
you're talking about a nobility rank. So count Volta created
(05:11):
a battery by stacking alternating layers of zinc. Lawrence just
checked out at this point zinc, brine, soaked cloth or paper, uh,
and silver. He used these alternating layers kind of a
sandwich here. And we call this a voltaic peel peel
because it's French and uh and and voltaic after volta, yes,
(05:31):
and so uh. The this this peel or pile if
you prefer, because it is a pile. Oh stuff. When
you put it in this this configuration, you start getting
these chemical reactions that emit electrons, and you could make
the stack taller and taller to get more electrons a
stronger flow of current through this peel. But in order
(05:53):
to do that you actually had to stack it up
so high that eventually the weight from the top would
start to squish the layers on the bottom, which would
kind of make the brine soak out, and that would
make it less effective, and also the metal itself would
start to corrode fairly quickly. The Brian and the movement
the electrons, right, it just wasn't wasn't a practical way
(06:15):
of generating electricity, but it showed the premise and it
gave scientists the idea of there's something here, and if
we can figure out other ways of generating the same
kind of energy, we might be able to harness it
for something. Skipping ahead, I mean there there are lots
of different developments in this technology. I have two specific ones.
I think you have a few more. The next really
(06:37):
effective one um was eighty six. Yeah, John Frederick Daniel,
who was an English physicist. He created what we now
call the Daniel cell, which was a you take a
glass jar and on the bottom of the glass jar
you put on in a copper plate. So copper plate
in the bottom of the glass jar, and there's a
wire from the copper plate that comes out of the jar.
(06:59):
Then you or copper sulfate on top of that copper
plate to about the halfway point of the jar. Then
you suspend a zinc plate in the jar, and then
you pour zinc sulfate solution on top of the zinc plate. Now,
zinc sulfate is less dense than copper sulfate, so zinc
(07:20):
sulfate will float on top of copper sulfate. If you've
ever played with liquids of different densities that had different colors,
then you know what I'm talking about. You can see
that actual level of division. Yeah, it's actually it's one
of my favorite things. I just think it's super cool
when it When I see that, I'm easily amused, I
admit it. But anyway, you also have a wire coming
from the zinc plate uh and exiting the jar. So
(07:43):
a wire attached to this would become that that zinc
plate becomes the negative terminal that's where the electrons are
flowing from, and the copper plate becomes the positive terminal
that's where electrons are flowing too. And so if you
were to connect the two wires together, it would very
quickly burn out this bad but if you were to
connect it to a circuit, it could actually do uh,
(08:04):
it could or a load as we call it, it it
could actually do work. So again, not terribly practical, it was.
It was useful for anything that was stationary. But you know,
you're talking about a liquid uh battery here, so it's
not something that you could easily carry around or put
into portable electronics, right right, Yeah, and there's there's a
lot of a lot more elegant ways of getting that
(08:26):
that electrol kind of solution of of you know, just
just a charged molecule then yeah, yeah, And it wouldn't
be until we developed dry cell battery technology that we
started to find practical ways of using it in portable means,
you know. And even then, you know, the batteries weren't
small enough to use and what we consider portable electronics today,
but you could move it around. Uh. The kind of
(08:48):
Daniel cells that that John Frederick Daniel created were useful
for different technologies, things like telephones. It was stuff that
back then you did not carry around. I don't know
if your kids know this, but telephones used to be
these things that were extremely stationary. It's only recently that
we started carrying them around. Uh. Anyway, that's the kind
(09:10):
of battery that became popular for that. Uh. Now, did
you have any other ones who want to talk about
before we move onto the basics of batteries rechargeable batteries.
The signs for that started um started with research around
eighteen fifty or so when a French physicist, Gaston Plant
invented the lead acid cell um and that that was
a that was a precursor to to modern day car batteries.
(09:33):
So there you have, you know, the discovery that this
chemical reaction that takes place within a battery, you get
compounds that form out of it, and it makes the
battery over time less effective. That's why batteries die. Eventually,
the active elements that would create the flow of electrons
end up combining with other stuff and for the purposes
(09:53):
of an of passing a current through a circuit, they
become a nert. Yeah. Yeah, something either wears out or
um or maybe the the anodeor cathode could could dissolve
in the solution. Right you just essentially what it means
is that you run out of the stuff you need
in order to make it to make this go right?
And so what what was it? Plant? Believe? Yes, what
(10:17):
Plant discovered was that for some kinds of solutions, if
you were to pass electric current through the system as
opposed to siphoning it off, you could reverse this process
and yeah, and create a battery that can be used
more than once. Right now, this does not work for
all batteries, which is why you can't just throw any
(10:38):
regular battery into a recharger and expect it to come
out fine. If you did that to a to a
you know, to Adris cell or something like that, mostly
just explode, right. Yeah, that these are has to be
batteries that are using specific uh compounds in it for
it to have this this reversible reaction, because not all
compounds will reverse some of them once they're done, they're
(10:59):
done and battery. We will talk about that a little
bit a little bit later. Um, but but let's let's
talk about how how exactly this this circuitry works. Okay, So,
if you've ever looked at a battery, you've seen that
there's a side that is labeled as a plus and
one that's labeled as a minus, so positive and negative.
If you're looking at like a nine volt battery, then
they're next to each other. If you're looking at double
(11:20):
a's or whatever, then it's on one end and the other.
So the negative end the that's where the electrons flow
out of. That's the electrons flow from that end through
a circuit and into the positive end. Uh. Now we
know that, you know, the the opposite charges attract, So
that's why the negative wants to get to the positive.
(11:41):
And inside the the the battery itself, there is a
chemical called or a compound called an electro light. Now
the electro light has a very important job. It blocks
those electrons from just passing from the negative side to
the positive side directly. Direct That would burn burn everything out. Yeah,
that you wouldn't You wouldn't be able to power anything.
(12:01):
The battery would just you would just have a chemical
reaction inside a canister and it would be dead within
however long it took for those reactions. Yeah. Um. So
it does allow ions to pass through, but not electrons,
and that becomes important. So the negative terminal is connected
to something that's called the anode. The positive terminal is
(12:23):
connected to what we call the cathode, and these together
are the electrodes of a battery. Then you've got the
separator between the anode and the cathode that's presenting that's
preventing those two sides from reacting to each other. And
you have the electro LTE that allows the electric charge
to flow between cathode and anode, allowing the ions to
pass through while making sure the electrons don't. And then
(12:44):
you have a collector, which is the part of the
battery that conducts the charge to the outside of the
battery and through whatever the load is, the electronic load,
so the circuit um. So within that anode side, the
negative side, the chemical reaction that takes place is called
oxid ation. It's an oxidation reaction. This ends up releasing
ions and the ions move through the electro light to
(13:06):
combine on UH the other side, and then you've got
UH the release of electrons that go through the circuitry.
On the catholic side, you've got the reduction reaction. That's
where the catholic material and the ions UH combined with
the electrons that are coming in through the circuit that
(13:27):
they form a new compound. And so essentially you've got
the anode freeing up electrons. The cathode accepting electrons, and
the electrons do work along the way. So if you
were to actually connect a wire from the negative terminal
to the positive terminal, you would allow that that pathway
to be open and it would just start to burn
up that battery pretty quickly. Don't do that. It's a
(13:52):
waste of batteries. It's going to heat up that wire.
It doesn't do anything other than kill your battery. But
but that's what happens. It's so when you've got it
plugged into something, whenever you turn the switch on to
whatever it is, whether it's a you know, a lightsaber
or a phaser. You know, I allow all kinds of
science fiction toys for batteries. But whenever you turn it on,
(14:15):
it opens up that circuit and that allows the electrons
to flow through. And when you turn it off, then
the one of the gates gets closed essentially, and you
no longer the connection is no longer there, so the
battery stops the chemical reaction. It has to have that
pathway open for the chemical reaction to keep going. Now,
there are several different basic types of batteries that are
(14:37):
out there, and we're just going to cover a couple
of them, and we're covering them based upon the stuff
that's inside them, right, because there's a whole bunch of
different substances that you can use to create these reactions.
Like like we said, so yeah, so so one basic
type is the is alkaline batteries. Uh, the anode and
alkaline batteries tends to be zinc powder. So the anode
(14:58):
again is that negative side that's the electrons are coming from.
The cathode side has typically manganese dioxide, and the electrolyte
is typically potassium hydroxide. These are the kind of batteries
that you typically find in double a's, C and D batteries. Right.
These are all examples of this is an example of
dry cell batteries. Yes, which dry cell batteries. One of
(15:20):
the big benefits of those that you don't have to
worry about liquid slashing around inside the battery, so that
allows it to be used in lots of applications. You know,
anything that's liquid obviously you can't shake around too much
or else just gonna disrupt it and you're not gonna
have a working battery. For they're more they're more more volatile. Yeah,
you want that, you want then a very h stationary position.
(15:41):
Then you've got zinc carbon batteries. Uh. These have an
anode that has that's zinc obviously. Uh. And then you've
got the meganese dioxide cathode. But the electrolyte in this
case is often either ammonium chloride or zinc chloride. These
are often found in triple A, double A, C and
D dry cell batteries. Then you've got lithium ion batteries.
These are the ones that we find in laptops, smartphones, cameras,
(16:05):
that kind of stuff. They are rechargeable batteries and they
have different materials in them. But uh, one common version
of lithium ion batteries uses a carbon note and a
lithium cobalt oxide cathode and uh and yeah, these are
the ones that we use when we're recharging our our
various electronics very frequently anyway. Then you've got lead acid batteries.
(16:29):
These are the ones that you often find in cars.
These are more heavy duty, right, they are more volatile.
They do include liquid, Yeah, they include their they're they're
electrolyte tends to be sulfuric acid. This is one of
the reasons why you want to be really careful with
car batteries because the materials inside them can be very
caustic and and they can damage you your stuff, your car.
(16:51):
That's why you know you've got to be really careful
with these things. Um, they tend to have uh, lead
dioxide and metallic lead as their electrodes. So yeah, the
rechargeable battery we've already talked about, that's the kind where
if you put the electric current through the battery, you
reverse this uh, this chemical reaction. Uh. It depends upon
(17:13):
what that rechargeable battery is made from, whether how effective
this this process is right, because there's some kinds of
rechargeable batteries that have well they have a memory, and
that memory is not a good one. The memory effect
is what I'm talking about. So I don't know how
many of you are familiar with this, but if you've
(17:36):
ever heard someone say that before you recharge your device,
you should make sure that it's completely that the current
charges completely out. This was due to some some older
types of batteries that have been mostly replaced by lithium
ion batteries. Nickel cadmium is the main culprit here. So
the problem that some people notice with nickel cadmium is
(17:59):
that if you used a nickel cadmium battery for a
while and then you recharged it before you had completely
discharged the original charge, it wouldn't hold as much of
a charge the next time. So let's say that I've
got a device that has a nickel cadmium battery in
it and I run it down to about left like
it's it only has charge left, and I decided to
(18:21):
recharge it. Well, now it's new maximum charge is more
like eight of what it used to be because I
didn't let it go. It remembers that, but it doesn't
let me actually consume that power anymore. So yeah, that
was a problem. Now most batteries now don't have that issue.
(18:41):
I mean, there's still a minor memory effect in some
rechargeable batteries, but it's not nearly as dramatic as it
the older batteries were, right, So so yeah, so if
you are using a lithium ion battery and someone tells
you that thing, you can you can tell them that
we told you no, No, not as big a deal.
And another interesting thing about batteries is what happens if
(19:02):
you place them in series versus in parallel. So in
series it sounds kind of you know, is what it is.
You've you've got them hooked up so that they are
all the charges running through one and then another and
then another. Yeah, in a sequence exactly. And uh, if
you do that, you increase the voltage of the output. Now,
(19:22):
if you put them in parallel, you increase the current.
Now you might wonder what's the differences voltage and current
if you're if you're not really familiar with electronics. I
always have to look this up because I I I,
I always second guess myself. But voltage measures the energy
per unit charge. And you can think of that is
it's how strong the electrons are pushed through a circuit.
(19:45):
So think of it like water pressure, you know, through
a hose. So the greater the water pressure, the harder
that water is being pushed through the hose. That's essentially
your voltage, it's you know. And then current is the
rate at which electric charge passes through a circuit. Now,
voltage will stay constant, the voltage output will stay constant
based upon whatever kind of battery you have, or whether
(20:07):
or not they're in series. Uh, but otherwise it's going
to remain the same current, however, will vary depending upon
the load you place it, uh, you place on it,
so and that can like the resistance of a wire
can affect what the current is. So current is variable.
(20:28):
Voltage is not, and uh, apart from the fact that
if you put them in series, you increase the voltage,
but once you've done that, it does not vary. Um.
All right, Well that's the basis the very basic foundation
of batteries. And in the moment we're going to talk
about why we haven't moved very far away from this
(20:50):
basic explanation we just gave you. But before we do that,
I'd like to take a quick moment to thank our
sponsored all Right, so we're back, uh, and we've learned
the basic function of a battery and how it does
what it does. So what's the problem. Why haven't we
made super batteries that last forever and never need to
(21:10):
be recharged and can put out more energy than uh
the generator? Yeah, well, I mean, you know, there's the
first commercial dry cell batteries premiered in and they haven't
really changed all that much since then. Yeah, We've we've
experimented with different materials, but the actual process has remained
(21:31):
very much the same, And there are physical limits that
chemical batteries have. They can only generate so much electricity
through these reactions. There have been a few permutations of
different things. In addition to those nickel cadmium batteries that
that have the memory effect problem that we mentioned earlier,
there's there was also some some nickel metal hydride, but
(21:53):
they had a really short shelf life. They would start
degrading pretty quickly. Yeah, that's another thing about some types
of batteries that lithium ion batteries have that problem as well. Um,
they're they're less bad at it, but they're still not ideal. Right,
the idea being that these these chemical reactions, like the
longer the battery sits idle, the less juice. Yeah. And
(22:15):
and and this doesn't have anything to do with how
much you use it. It's it's from the moment that
they're made. Yeah. Yeah. And also you may have heard
stories about, well, if you want to keep your batteries
from degrading, you should put them in the refrigerator. Don't
do that. Don't do that because that actually it actually
slows down the chemical processes that happen when you yeah,
(22:37):
when you're when you're trying to use the battery, and
you're going to not get as much juice as you
thought you were because the chemicals themselves are too cold
to have those chemical reactions happen at the correct rate.
They're still going to happen, but you're gonna get a
easily amount of juice out of it, right. So, so far,
lithium ion batteries, especially for small uses, have have been
(22:57):
have been pretty pretty rad um. How however, they are
very sensitive to high temperatures um, you know, which is
occasionally why they wind up exploding, bursting into flame. Let's
let's also point out that lithium is an alkali metal,
so and we'll we'll talk about a little bit. We're
gonna talk about a AH, a possible future type of
(23:19):
battery that people are working on right now, where that's
really an issue. Both lithium and sodium are being considered
for new types of batteries, but both of them are
alkali metals. The big problem, there are several problems, but
the big problem I would say with that is alkali
metals belong to a class where they tend to be
(23:39):
let's say, reactive when they come into contact with water.
So if you've ever heard stories about sodium and water,
or if you've ever seen anyone demonstrate what happens when
sodium encounters water, uh, you know it's explosive. The same
thing is true of lithium. All right, this is where
we get a little chemistry. Lesson, everyone, go and get
your period audic table of elements. I'll wait now. If
(24:03):
you look at the left hand side of that table
of elements, you're gonna see that down the line you're
gonna have lithium and you're gonna have sodium that are
both in that same line, as well as potassium and
some other alkali metals. That means that those elements share
common characteristics, and one of those is when water comes
in contacts, sometimes things go boom. So first of all,
(24:25):
never never ever play with these I don't if you
get hold of sodium or lithium, never play with that
and water. This is seriously dangerous stuff. Also, probably just
just don't. I mean, because because water is in the
air around us in in great enough quantities that hypothetically
it can burst into flame. I know of someone I didn't.
(24:47):
This is a friend of a friend's story, so it's
possibly apocryphal. So it could be urban legend. I admit that,
But I know of someone who pocketed some sodium from
his chemistry class and then was walking around with it
in his pocket, and his body was giving off moisture,
(25:10):
and so he began to feel a burning sensation in
his pants and immediately ran to the bathroom and pulled
the sodium mountain threw it into the toilet, which then exploded. Yeah, again,
could be apocryphal. This is it was a story about
a high school student who went to a rival school,
so it could have very well been one of those
stories where ha ha, the people who go to that
(25:31):
school are so dumb, so much more dumb than the
people who go to my school, which is saying something.
I'm just kidding. I love all my classmates Spartans, but anyway,
you were the Spartans, I was the Spartans. Were Spartans
Spartans together. This is tech stuff. So but the point,
the point being that these these these elements have serious
(25:53):
drawbacks to him. And that's one of the reasons why
the another reason why battery improvement has gone so slowly,
because we have to find safe ways to handle this
stuff so that it doesn't come into contact with water
and then just blow up. Right. Part of that in
lithium ion batteries specifically, is that they have to have
a very small, very simple onboard computer to to manage
the way that all of the bits flow around in there,
(26:16):
and uh and and that that makes them pretty expensive.
Lithium is already pretty expensive, but it makes them even
more expensive than they would already be. Now, we have
seen some improvements with battery life in recent years, but
a lot of that doesn't come from improvements in the batteries.
It's coming in improvements in the actual electronics. We are
finding more efficient ways to generate the stuff we want.
(26:37):
So your smartphones, if you've got a smartphone recently that
has a decent battery life, it may not be that
the battery is so much better. It's just that the
people who designed the hardware and software we're able to
maximize performance while being as efficient as possible. So you're
still working with the same basic amount of Yeah, but
(27:00):
you don't need as much of it to do the
stuff you are doing exactly. Speaking of that juice, though,
the problem with batteries, and the reason that that that
gasoline has not been ousted completely by batteries. Is that
gasoline has an energy density of something like thirteen thousand
watt hours per kilogram, which is which is just a
measure of how much of juice it has, how much
(27:20):
how much, how much work they can get out of
a given amount of gasoline. Sure, um, the best lithium
ion batteries only hold about two hundred what hours per kilogram,
so with of a of a hypothetical in a perfect
world situation, four hundred possible, So still vastly underpowered when
you compare it to gasoline. Right now, there are some
(27:45):
people out there, very very smart people working on batteries
that would have much higher densities power densities for their
batteries if they can get the batteries to work, if
they can get the the components to to to play nicely,
to not explore oade, and to work on larger scales,
and to work after more than three charges. There are
a lot of barriers that are in place, and we'll
(28:08):
talk about some specific uh cases, but keep in mind
there have been dozens, if not hundreds of different experiments
and trying to improve battery technology, and most of them
just have not panned out. They might have seen promising
at the beginning, but when you get to a point
where you're thinking, all right, how are we going to
scale this up where we can actually manufacture it or
(28:29):
create a battery large enough to do something useful, and
then things start to break down. So one of the
ones I wanted to talk about where these things called
micro batteries, And this was something that that we received
from that initial request to talk about battery improvements. And
this is a story about a team of researchers from
(28:50):
the University of Illinois uh talking about a particular type
of battery that uses these very tiny electrodes and lots
and lots of them, and their three dimensional electrodes, and
it was almost like these electrodes are kind of intertwined together,
so they're very close together, which allows the ions to
pass very very quickly. It also allows electrons to flow
(29:14):
very quickly, and the idea being that you would be
able to release quite a bit of energy in a
short amount of time, faster than you could with most batteries,
and you could also recharge the battery way faster, right,
because that thoroughput speed has a lot to do with
how effective a battery is. Yeah, and in fact, according
to several articles that were posted about this technology. BBC
(29:36):
did one as well as some other outlets. The claim
was that such a battery would be reached could be
recharged one thousand times faster than competing technology, so you
could turn your you know, plug your smartphone in. Let's
say your smartphone has one of these batteries in it
and you plugged it in. After a second, it's fully recharged.
(29:57):
You don't have to leave it there for hours for
it to charge, which is that's a very attractive thing.
So you're thinking, well, if it can release lots of energy,
and if it can be recharged in a blink of
an eye, where's the problem. Well, mostly the problem comes
in from the manufacturing side and the scalability as well
(30:18):
as uh the fact that it's not the most reliable technology.
Ours Technica actually ran a great article where they really
looked into this and and dove deeper than a lot
of the other outlets did to kind of take a
look at this technology with a skeptical eye, just to
make sure that it really did measure up to the hype,
(30:38):
because we've seen this before with battery technology, right, and
this isn't to say that they want the team won't
figure out a way of of solving the problems that
they face. But here are some of the problems. One
of them is that it's really hard to manufacture these things.
The way that the team was doing it, they were
using this uh, this essentially gold to make these little
three dimensional um electrides electrodes sort of, and then they
(31:02):
used poly styrene uh, little little tiny poly styrene pills,
essentially packing them in there, twisting the electrodes around, coding
it and nickel in a well in a combination of
nickel and tin and then UH nickelton alloy actually, and
then coding the rest of it with manganese oxy hydroxide uh,
(31:26):
and then melting away the poly styrene so it it's gone,
then immersing the whole thing to a liquid that was
heated to three degrees celsius or five degrees fahrenheit. And
so it's what even the team has referred to as
a boutique manufacturing approach, meaning that it's very detailed, it's painstaking,
(31:48):
it is not automated, extremely expensive. Yeah, it's no time
consuming exactly, not something that's scalable to mass manufacturing methods
right now, certainly right that's not to say that they
wouldn't find some other way of doing it. They may
find a way of doing it where it doesn't require
this series of painstaking steps in order to get the
result that they want, but uh, it's not ideal. Another
(32:12):
problem is that the electrolyte they're using is combustible, so
that's always a concern. If you get it too hot,
it could burst into flames. Uh um, or you know,
if you were to get it close to a flame,
it could catch fire. And on top of all that, uh,
the battery loses about five percent of its capacity with
each charge discharge cycle, so after fifteen cycles it would
(32:35):
be down to about two thirds of its original capacity.
And uh, if you were to do a full discharge
full charge, it might be even worse than that. So
while it would recharge very quickly, it would have a
little less juice each time. And so after you recharge
it twenty times, yeah, you have to buy a new battery,
(32:57):
new battery, right, So, uh, that raises lots of problems
to waste problems. For example, like even if you were
to say, well, that's acceptable because I want to be
able to charge my phone in the second, you can
do that twenty times, and then you have to go
buy a new battery. And especially when the when the
technology to create it is so so detailed and expensive,
and to be fair, you wouldn't even you wouldn't even
go twenty times, right because each time you would have
(33:20):
less juice and so your your phone would be less
and less useful over time. So after after your phone
doesn't last more than a couple of hours, you think, well,
I gotta get a new battery. So that might be
six or seven recharges, depending upon how hard you are
on electronics. If you're me, then you'd be like, all right,
recharge it, give me a new battery. So um. So
(33:42):
that that's the downside to this micro battery technology. That's
not to say again that they won't find ways around that.
Engineers are brilliant at finding ways of fixing problems. But
it's not going to be the revolutionary battery technology that
we're all going to see in our smart on in
the next few months. It'll it'll at least be a
couple of years before we can see this rolled out
(34:05):
in any way, assuming that they find a way to
fix these problems. Right. One of the other ones that
I wanted to talk about our lithium air batteries, and
this is where we're getting into those alkali metals and
the concern about how they react with water exactly. You know,
they could hypothetically store up to four times as as
much as as lithium ion batteries, as much power as
(34:26):
lithium ion batteries, but they work in that um. Lithium
combines with with oxygen that's trapped by a carbon surface.
Carbon nanotubes are are popular right now and um and
the resulting interplay of these lithium ions and electrons induces
the flow of current. UM. Yeah, you get a get a.
One of the by products you get out of this
(34:47):
is lithium peroxide, which is a problem because as it accumulates,
it starts to make it more difficult to recharge the battery. Right.
So they they've only recently figured well, they they've had
a bunch of of barriers to to making this work.
That is, that is one of them they're they're starting
(35:08):
to For a long time, they didn't understand why the
electrochemical reactions were going so poorly in these things, and
it wasn't until uh May thirteen that that researchers at
m I T and Sandia National Labs announced that they
were starting to be able to observe the reactions at
all to figure out why this isn't working, and that's
when they started seeing this lithium peroxide forming that was
(35:31):
inhibiting the flow of electricity. And uh, they did discover
that if the electricity were flowing, that the lithium peroxide
was starting to reduce around the trouble spots. And they
figured that if they could improve the electron flow of
the battery overall, then they might be able to get
around this problem so that recharging doesn't become an issue. Right. Uh,
(35:55):
that that explosion thing that we mentioned earlier is still
at issue because when when you're dealing with you know,
these these carbon surfaces are allowing air to basically breathe
into the battery, and since water happens in air, Yeah,
you have to find either a way of coating the
lithium inside the battery so that the water would not
react with the surface of lithium, or you'd have to
(36:16):
find a way of filtering the water out entirely, so
that membrane at the top end, yeah, hydrophobic membrane, that's
what we'd like to call that it's scared of water.
It pushes water out, So uh yeah, it's that that's
an issue. Now, there is a potential alternative to lithium
air batteries called sodium air batteries that are even they
(36:38):
are they may not be able to hold as much
energy as a lithium a battery. It's a lower theoretical
energy density but a higher practical energy density at the
current moment exactly, so current moment. So yeah, no, it's
it always happens. You can't get around it. But yeah,
that's so that's a stability. But again, remember sodium is
(37:01):
probably that alkali metal groups, so against same issues. You
get that water in contact with sodium and battery goal
boom instead of instead of zap zap. Right. Uh. There's
there's also research being done into what's being called solid
state batteries UM, which are kind of kind of the
lithium ion um solution to dry cell batteries. It's it's
(37:24):
using um thin layers of solid electrolyte instead of instead
of the liquid that most lithium ions use. Yeah, and
then there's a I read on Wired this interesting idea
of spray can batteries where each of the each of
the elements that you would find within a battery, the cathodeiana,
the electrolyte, all that is represented by a different can
(37:46):
of uh sprayable material. So you could actually spray this
material onto different surfaces and make a battery that way.
And the idea being that this would allow you to
create batteries in devices that would break the battery designed
directly into the device, so you wouldn't have this blocky
battery compartment. Now, it's not saying that these batteries would
(38:07):
be particularly efficient or powerful compared to what we have now,
just that this would give us more opportunity to explore
different ways of shaping batteries so that they are part
of our electronics and not just you know, again, not
just some clunky thing that you have to find make room,
make room for it, right, right, and and also not
(38:28):
so heavy, um what would be terrific. That reminds me
of the nanocomposite paper batteries that some people are are
working on. These are these are composed of cellulose and
um an aligned carbon nanotubes woven together um and and
they're they're they're small, they're flat, they're flexible, they're implantable. Um,
they could hypothetically be put into medical devices. Yeah, these
(38:50):
could actually use biological fluid as ionic fluid. So it
ends up turning your body's fluids into the electrolyteed needs.
This is just making think of idiocracy. It's electrolyte. It's
the thing that plants crave um. I was doing the
hand gesture and everything for those of you are fans
of that movie. Then there's also uh, you know, the
(39:10):
Verge reported on bacteria that are able to transfer electricity,
and scientists had known about this for a while, but
they weren't sure about what the mechanism was, like how
did it transfer electricity? And they discovered that that there
were proteins on the bacteria surface that we're responsible for
electron transfer. Uh. The bacteria is uh, this is this
(39:35):
is going to be a train wreck of a pronunciation
of me luck she wa nella oneidnisis. But anyway attaches
to rusty iron and other materials and breaks those down
and in the process of breaking down these materials, it
releases electrons. So why are we interested in this? Because
(39:57):
by studying biological organisms that can emit electricity as part
of some process where it's consuming something, we might be
able to create biological batteries, and these are these are
a little bit more of fuel cell really than a battery.
But and and to explain the difference, a fuel cell
(40:17):
is a device that you put fuel into and then
there's a chemical reaction that generates electricity, and then you
refill the fuel cells. So and you know, with a battery,
what you're doing is you're using an electric uh or
electrochemical reaction to harness electricity, and then you either have
to reverse the reaction in order to get the battery
(40:39):
to do it again, or you have to replace the battery.
Fuel cell, you just refill it with fuel. So hydrogen
fuel cells are the ones that most people know about
because those the ones that we've talked about for things
like cars. Hydrogen fuel cells use hydrogen, which is the
most plentiful element on Earth, although you have to break
it up from other stuff. It doesn't it doesn't it's
(41:01):
not so plentiful in its pure state. It's usually it's
it's in water, which is very plentiful, and hydrocarbons as well,
also very plentiful. But you have to separate the hydrogen outfast,
which requires energy a lot of energy. But once you've
got it, assuming that you've assuming that you found some
sort of hydrogen mine where it's not going to take
you too much energy to get it free. Um, you
(41:23):
put hydrogen on one side of a membrane um that
has a catalyst on it, usually something really expensive like platinum,
and then on the other side of the membrane you've
got oxygen. The membrane allows the hydrogen ions to pass through,
but not hydrogen atoms. It has to lose the electrons
for it to pass through. The electrons go through a
(41:43):
circuit just like it would with a battery and combine
on the other side. So the hydrogen ions passed through
the membrane and that meets up with the oxygen and says, hey,
you wanna you wanna go do something? I got my
buddy here, my buddy here, and I would love to
take you out to dinner. And so the two hydrogen
take out the one oxygen to dinner. Meanwhile, the electrons
come back over through the circuit and recombined, and then
(42:06):
you get water. So the output of a hydrogen based
fuel cell is water, electricity, and heat, which is why
every pretty sweet deal. Yeah, I think This is why
we would love to use it to fuel cars because
instead of giving off all these different greenhouse Yeah, now,
water vapor is technically a greenhouse gas, but it's water vapor.
(42:28):
It's not carbon dioxide, it's not methane or anything like that.
So that's why they're very attractive. But they are you know,
they're similar to batteries, but there there is a difference.
There is I do I do have a have a
bio battery that I was just reading about research last
November at m i T. Harvard and the Massachusetts Eye
and Ear Infirmary. Um the okay, so, so mammals have
(42:53):
in their inner ears chamber that's filled with ions and
um uh. These these ions produce use an electrical potential
which drives neural signals. And what this means is that
this is the chamber in your ear that that lets
the vibration of your ear drum be converted into an
electrochemical signal that your brain can read and then interprets
(43:15):
the sound and interprets a sound. Um and so but
but but you've got this this inner chamber that's just
hanging out with ions in it, which is a potential battery.
Um and these researchers put UM put some electrodes in
there along with a very low power electronic device, and
UM the chamber produced enough power with these electrodes to
(43:38):
power the device to wire wirelessly transmit data. That's pretty
cool to to an external drive. Now again we're talking
about you know, we're not talking about stuff that's that's
advancing the power of batteries, but we are looking at
brand new applications that could that are really exciting. Yeah,
it's just but again, this isn't the thing that's going
to make your cell phone last longer. Probably probably not.
(44:02):
It's it's really really really low power, but it would
it would mostly be great for for medical advances in
um hearing aids. Yeah. So anyway, anyway, the advances we're
talking about, for the most part, are again just refining
the technology that we already have. It may turn out
that we just have to find a different means of
(44:23):
generating electricity that goes away from this electrochemical model entirely
for us to get beyond this this bottleneck, or if
one of these other like the if the lithium air
or sodium ayor batteries work out, or if the micro
battery works out, maybe maybe that will be that that
would be a huge leap ahead, and if either of
those of any of those were any any more efficient
(44:45):
chemical combination. Right, So there, we're not saying it's impossible.
We're just saying that it's been several decades and we've
only seen incremental improvements. So don't be surprised if that
stays the same. If it doesn't stay the same, aime,
if we do have this huge leap, that's gonna be
awesome for everybody, and that's what everyone wants. Just you know,
(45:07):
be prepared to wait. Just what I'm saying, all right,
So I think that was a good explanation of batteries,
also what the future is and why it's kind of
lagging behind at least in respect to the way processors
are taking off. If you guys have any ideas for
future episodes, there's a concept you really want to explained,
or there's a particular gadget or computer that you think
(45:29):
needs to be talked about, or there's a company or
a person let us know, send us an email that
address is tech stuff at Discovery dot com, or drop
us a line on Facebook or Twitter. Are handled. There
is text stuff HS w and Lauren and I will
taught to you again really soon For more on this
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