ICE Batteries And EV Batteries
Anybody who’s left the lights on in their car overnight or helped a mate push-start a sulky ICE vehicle knows only too well that all cars have batteries, not just EVs. So you might be wondering about what the big deal about battery life and battery fires and battery range is all about. To understand this, it’s time to go back to basics and to look at what a battery is and how it works.
Your bog-standard battery in an ICE vehicle is a lead–acid battery – the lead is why it’s so heavy, and the acid is why the batteries are “interesting” to dispose of, as the acid in question is often H2SO4 or sulphuric acid. Car batteries were a very welcome replacement to the old-fashioned method of getting the motor started with a crank handle. These lead–acid batteries are rechargeable, as the petrol or diesel motor handily charges them back up. This is why you can drive for hours and hours with the headlights on at night without the battery going flat, but if you leave lights on overnight, it will go flat.
In a lead–acid battery, both the anode (the bit that produces the positive charge) and the cathode (the bit that produces a negative charge) are made from lead and lead dioxide, respectively. The electrolyte (the bit that gets the electrons flowing thanks to chemical reactions) is sulphuric acid. Hook this up to a circuit and the electrons whizz around it in an attempt to get into balance, creating electrical current that we can use to, say, create a controlled explosion to power a vehicle. Most batteries also contain separators that stop the anodes and cathodes touching each other, which can happen if dendrites (branching crystals) start to form. If you want to get really technical, a battery is made up of a lot of individual cells containing an anode, a cathode and the electrolyte. In fact, that’s why a battery is called a battery – it reminded the early inventors of an array of cannons or other weapons ready to fire. The batteries can last for years, especially if turned over regularly and cared for properly (and that’s another subject for another day).
The basic design of a lithium-ion battery (LIB) inside an EV is similar. It’s got an anode, a cathode, an electrolyte and a separator. In this case, the cathode is made from more exotic metals and oxides, such as lithium cobalt oxide, lithium nickel cobalt manganese oxide and lithium nickel cobalt aluminium oxide (try saying that quickly!), and their conductivity is improved by mixing them with conductive black carbon. The anode is usually made of graphite. The electrolyte has more lithium, specifically lithium salts dissolved in organic solvents that have plenty of the lithium ions that give the batteries their name. These batteries are a lot lighter than lead–acid batteries and can deliver a lot of punch. They also have a longer lifespan than other types of rechargeable battery, such as ni–cad (nickel–cadmium) batteries and don’t have the problem of “memory”.
The problem with lithium batteries is that the electrolyte is very, very flammable. The lithium is also prone to growing dendrites, which can cause short-circuits (and thus fires), especially if it’s charged too fast, overcharged or charged at too low a temperature. Lithium also gets prone to throwing a dramatic wobbly if it gets too hot or if the battery is damaged. It’s a case of the lithium’s strengths – its unstable chemistry that allows it to generate a charge – being its greatest weakness.
Lithium-ion batteries haven’t been around for as long as lead–acid batteries, as they only came on the scene in the 1960s and were popularised by Sony in the late 1980s. The lead–acid battery, however, has been around since the 1880s. In other words, it’s early days for lithium-ion batteries, and they’re working hard to improve the batteries and make them better.
But what happens when the batteries come to the end of their lives, which is inevitable? This is more of an issue with lithium batteries, as lithium is a much rarer metal, whereas lead is pretty common and humans have been playing around with it for millennia, although it’s now not used as much in common products (except for batteries) because of the health hazards.
The good news is that both types of battery can be recycled. It is possible for both metals – lead and lithium – to be cleaned up and used in new batteries. In fact, if you have an old battery of either type, then the best thing to do is to take it down to your nearest recycling centre and get it dealt with. Otherwise, both types can be a bit nasty, although the nastiness of lithium is more dramatic (fires) than that of lead (slow poisoning). Most lead in the batteries can be recycled; once again, the rate of recycling of lithium is a bit behind, most because it’s still a young technology. The acid inside a lead–acid battery can easily be neutralized or put to other uses, including making fertilizer.
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