In America, people buy three billion of
these every year.
Not double A's but batteries in general, and without some kind of battery to keep your phones ringing,
your laptop searching, your flashlights reading, your cars starting, what would you do? We're totally dependent on battery technology and even though
it's changed drastically in just the past few decades, the basic idea goes back
thousands of years. So, how did we get here and where does battery power go from here?
In the simplest terms a battery is a device that stores potential chemical energy and converts it into electricity through reactions known as oxidation-reduction reactions.
Any battery is basically an electrochemical cell and in order for it to work it has to have three things:
A positive electrode or cathode that wants more electrons,
a negative electrode or anode that gives up electrons, and an electrolyte that allows ions to move back and forth between the first two thereby
creating a flow of electricity
You probably heard from us or someone else how to make a battery out of a lemon where you can see these principles at work.
Just take some copper wire which acts as the cathode, a zinc coated nail for the anode, and a lemon which provides the electrolyte medium
that connects the two. The difference in
electronegativity between the anode and the cathode
causes the reactions that produce a small charge of electricity. It took a while for humans to get wise to the idea that these stored
electrical charges could be useful. In the late 1930s German archaeologist Wilhelm Konig was poking around in Baghdad when he dug up an unusual
artifact that made the world rethink the origin of batteries. It was a 13 centimeter
clay jar that held an iron rod
encased in a copper cylinder and contained traces of an acidic liquid, probably wine or vinegar.
It was a really, really, really old battery - like
2,000 years old!
This blew some minds and the artifact remains kind of an oddity.
Experts debate what these batteries might have been useful for but some believe they were tools in
electroplating: the process of using electricity to apply a thin layer of gold or other metal onto a different metal to make jewelry and other
ornaments. Scientists have actually
replicated these battery jars and found that they could produce one to two volts of electricity. For sure batteries have improved a lot since then but
the basic concept has
essentially remained the same as those Baghdad jars.
Italian Physicist Count Alessandro Volta was long credited with creating the very first modernish battery back in the late 17 hundreds.
He stacked layers of brine-soaked paper between silver and zinc plates to form what became known as a
voltaic pile that emitted a steady current of electricity. Today we measure electromotive force in volts in Volta's honor.
But, while everybody agreed that this pile was pretty sweet,
it did have some major drawbacks like how the salt water quickly corroded the metal plates.
It wasn't until around 1836
that English chemist John Daniell made some major improvements.
He invented the Daniell cell by placing a copper plate at the bottom of a glass jar half-full with copper sulphate solution,
then topped it off with a zinc plate
suspended in a zinc sulfate solution. The copper and zinc work on the same principles as that lemon battery we talked about but in Daniell's
cell because the copper solution is denser
it kept the bottom of the jar while the zinc solution remained floating at the top.
Thus creating the first positive on the copper end and negative on the zinc end
terminals of a battery. As long as the Daniell cell remained still, like motionless,
it worked like a charm powering things like doorbells and telephones for years.
It took another several decades for new improvements to pop up in the mid 1860s.
Frenchman Georges Leclanche developed a contained carbon zinc wet
cell. It was smaller, more rugged,
longer-lasting than the Daniell cell though it still worked by immersing its electrodes in an acidic solution, in this case
ammonium chloride. Later improvements used a barely moist paste of ammonium chloride as the electrolyte instead of a liquid
which meant that the battery could be jostled around without spilling all over the place.
This was the dry
cell battery concept which we still see today in alkaline zinc carbon and mercury batteries.
By the end of the 19th century the National Carbon Company began selling the first commercial batteries in the U.S. That company eventually morphed into
Everready which then became Energizer which...
this guy, here and while today's batteries come in a wide range of shapes and sizes and
materials they all function basically the same way whether they're made of alkaline, zinc, lead-acid, or lithium. The electrochemical
reaction and all three key components of anode, cathode, and electrolyte all remain. Today, the biggest difference in battery types is between primary (or
disposable) and secondary (or rechargeable) batteries. Disposable batteries are one-shot wonders.
They produce electricity so long as the anode's chemicals keep releasing electrons and the cathode keeps accepting those electrons through the electrolyte.
But once the chemical reactants are drained, the reactions stop and the battery dies.
The lights go out. These include your everyday alkaline batteries which use an aqueous alkaline for the electrolyte.
They typically connect a zinc anode to a cathode made of manganese dioxide.
Rechargeable batteries, like nickel cadmium or the lithium ion ones tucked into your laptop, operate a lot more like two-way streets.
They lose all their chemical juice while producing electricity,
but they can be recharged when plugged into an electrical source because the particular chemical reactions
they use can be reversed. Lithium is a super, super reactive element
and its ions can be used to store a ton of energy. Lithium ion batteries use lithium cobalt oxide as the positive electrode,
carbon as the negative, and an organic solvent, often ether, for the electrolyte. These batteries are generally far lighter than other types of
similarly sized rechargeable batteries which makes them particularly good for use in mobile devices. They also use oxidation-reduction reactions of course
but because of the particular materials they use, their chemical reactions can be reversed with the input of energy and subsequently charged back up.
So, when your laptop's on battery mode discharging its juice, those lithium ions are moving from the negative carbon electrode over to the positive
lithium cobalt oxide electrode.
But when the battery gets plugged into the wall it
recharges itself when those ions move back from the positive electrode to the negative side. It's like if you could put the electrons back
Into the zinc covered nail in your lemon battery and take them out of the copper wire over and over again.
Thanks to lithium you can. The fact that you find rechargeable batteries all over the place now
but you didn't like 20 or 30 years ago might make you think that they're a fairly new invention,
but they've actually been around for over 150 years or at least one of them has. In 1859
Gaston Planté invented the lead acid battery, the very first ever
rechargeable battery. This heavy,
but effective, wet cell combined a lead anode and a lead dioxide cathode bathed in a tub of sulfuric acid
and it worked so well that it is still starting cars today.
Lead acid batteries do a great job of delivering a big burst of energy to start your car's engine and then
ration out extra energy for running your radio and lights and A/C and iPod while the gas-powered engine takes over the work of moving the car,
but electric and hybrid cars ask a whole lot more of their batteries and old-school lead acid rechargeables
just aren't enough to push around a Chevy volt so while an electric car might get an average of
130 kilometers off the juice of a lead acid battery, a battery that uses your old friend lithium gets closer to
350 kilometers off a single charge.
Not only that but lead acid batteries can only be recharged so many times before they die for good,
which you probably already know if you've had to jump-start your rig multiple times. So lithium ion batteries recharge nearly
perfectly and can be drained and juiced back up hundreds of times without losing efficiency.
Many believe the future of electric cars depends on building better and more efficient and more affordable
lithium ion batteries. Still electric car technology has a ways to go. As it stands not everyone has the time or patience to return home
And recharge a 450-kilogram
(yes,
they are that heavy) battery for eight hours a day and
the compounds that they run on do eventually get depleted after about five years
or 160,000 kilometers at which point you got to shell out ten thousand bucks for a new one or just get a new car
So, yeah, some kinks to work out all right.
We're getting there. The chemistry of batteries makes possible all of the
electronic wizardry around you and it's pretty darn cool to consider the basic function of those two thousand-year-old
Baghdad jars hasn't changed that much from electroplating ancient jewelry, to you
watching me right now, to the future of electric vehicles.
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