EV battery jargon buster

If your new car is going to be powered by batteries, instead of petrol or diesel, you’d better get to know the different types of battery that are available.

Wait, there’s more than one type?

Yes, there is.

You mean bigger and smaller, right? Like AA and AAA?

No, actually what we mean is that there are two distinct and different types of electric car battery available, which use different battery chemistry.

Should I have studied harder in my Leaving Cert?

No, we’ll keep this as simple as we can. Both types of battery use lithium for energy storage, because lithium is great at separating out the electrons from its atoms, thereby creating an ion – hence the name lithium-ion battery. Those electrons flow through the battery from a cathode to an anode, creating a flow of electricity, before joining up with their original atoms again and keeping the battery in balance.

Okay, I think I’ve got that. So how are there two different versions of this?

The basic principles are the same, but the two variations of the chemistry – lithium iron phosphate (LFP) and nickel-manganese-cobalt (NMC) work in subtly different ways.

Is one better than the other?

Not specifically, no. They’re good (and bad) at different things. Let’s start with NMC batteries, as those are currently the most common, and they’re the ones we’re more used to. With lithium as the storage material, the nickel, manganese and cobalt refer to the materials used for the battery’s cathode and anode, its negative and positive terminals.

NMC batteries can be designed around seriously high power outputs and can generally store more energy for a given size and weight than an LFP battery. So far, they’ve also had generally faster charging speeds (although that’s starting to change).

The downsides? NMC batteries are more expensive, generally, and use more rare earth metals, which can be environmentally (and socially) damaging. They are also much more likely to suffer “thermal runaway” and fires if damaged.

So LFP batteries are better?

In some ways, yes. LFP batteries use simple iron in the cathode (hence the name – the F in LFP comes from ferro, the Latin for iron) and don’t need any cobalt, so they’re much less harmful in terms of mining, etc. They’re also much more tolerant of regular fast charging and don’t mind being charged up fully to 100 per cent, unlike NMC batteries, which are happier being charged between 20 and 80 per cent most of the time.

LFP batteries are also much more robust when damaged and much less likely to start a fire. And they’re cheaper to make in the first place. So why doesn’t everyone use LFP batteries? Because, mostly, they’re less energy dense than an NMC battery, which affects range, and so far they’ve usually not been able to charge up as fast as a high-performance NMC battery.

You said “so far”

Yes, some LFP batteries are now starting to match their NMC equivalents. The likes of BYD (which designs and makes all its own batteries and only uses LFP chemistry) and Xpeng are now making LFP batteries that are a closer match for energy storage to NMC batteries and that can charge at frankly ludicrous speeds. Xpeng already has a battery in its G6 SUV that can charge at up to 541kW on a DC connection (that’s way more powerful than any current Irish charging point), while BYD is currently rolling out in China batteries that can charge at up to 1,500kW (!) potentially allowing for a 95 per cent charge in just five minutes.

So we’ll all be using LFP batteries in the future, then?

Possibly so, but that’s without considering solid-state batteries …

Solid state?

Yes, this is technology that’s been bandied about for almost a decade as the game-changer for electric car batteries, but that has also seemed just out of reach in production terms.

Why is it solid?

Batteries need an electrolyte – a pathway for the stored energy to travel from the negative to the positive terminals – and in both LFP and NMC designs this is a liquid electrolyte, which usually contains a chemical called lithium hexafluorophosphate, often dissolved in an alcohol-based solution.

It’s this electrolyte that’s the limiting factor in current battery design, and it’s why batteries need complex cooling and heating systems. Keep that electrolyte in its happy temperature zone – usually around 21 degrees – and all is well. Let it get too cold, and performance drops. Let it get too hot, such as when fast charging, and you can damage the battery. Let it get really too hot, and you’ve got a battery fire.

A solid state battery does away with all that, using an electrolyte that suspends the lithium hexafluorophosphate, or other chemical, in a ceramic material.

How does that help?

Well, it almost entirely eliminates the possibility of a battery fire, for a start, but better still is the effect on how much energy a battery can store and therefore how big a battery needs to be. It’s been estimated that a solid state version of a current 50kWh NMC battery, for example, could weigh as little as 100kg, instead of 500kg with current tech. Solid state batteries are also supposedly going to be way, way faster to charge, and harder to damage with repeated charging, improving battery life.

Who’s going to be first with this battery silver bullet?

Probably the Chinese. Geely has said that its solid-state batteries should be on sale from next year, and the good news is that, as well as Geely models, European-friendly Polestar and Volvo models are due to get these new batteries too. Geely is already talking about 1,000km ranges from these new batteries.

Stellantis Group (the likes of Peugeot, Fiat, Opel, Citroen, Jeep etc) and Mercedes are reckoned to be hot on Geely’s heels with solid-state tech, but there’s an interesting wrinkle – Ford is working on a new battery chemistry called Lithium Manganese Rich (LMR), and it reckons that this new design could be as safe and reliable as an LFP battery but much more energy-dense, which means more range for a given size of battery.

Who will win the battle of the batteries?

Most likely, it’ll be a multi-battery solution. Solid-state tech is, for now, expensive, so it will probably be mostly fitted to more expensive cars at first, while more affordable models will increasingly switch to LFP and, maybe, Ford’s new LMR design.