One electric vehicle uses approximately 4kg of lithium (4,000 tonnes per one million vehicles, for those in the back). By the year 2030, we’re expecting 30 million or more electric vehicles in Europe alone. Scarcer resources are also being lapped up in abundance — cobalt, the prominent example.
We’re a little short on water, too. Extracting one tonne of lithium from the earth devours 1,900 tonnes of water. A story for another day, perhaps.
Of course, historically, when we run low on hard-to-acquire supplies, countries with deeper pockets and larger weapons will wage war on those below them in the pecking order. That’s not my kind of thing, so let’s take a look at some alternatives.
A crash course on how batteries work
Batteries generate electricity through the movement of electrons around a circuit. The circuit, however, is not complete until the battery is connected to some apparatus (such as when you plug a battery into a torch).
When the circuit is complete, electrons donated from the material in the ‘negative’ terminal flow through the circuit towards the ‘positive’ terminal. Many factors affect properties of the battery. Most significant tend to be the materials that the lithium sits in (Normally the cathode material), and the ‘dopants’ — that is, the other, non-lithium, metals which sit within the pockets of empty space in an electrode.
For lithium-ion batteries, It looks like this:
You will notice that the difference between charging and discharging is in the passing of lithium ions through a separator. Electrons can’t pass through the separator. They are forced to go the long way around — through the circuit. To reconcile with their beloved lithium ion counterparts, they must pay the toll of powering our apparatus.
A final point here: batteries in large apparatus (such as those which power electric vehicles) — I’ll refer to them as battery packs — are made up of hundreds of these ‘cells’, as they are called, joined together. If one or more cells in a battery pack get bashed about sufficiently, you might see what’s called thermal runaway. Maybe the circuit in one ‘cell’ is broken and leaks its energy into the open. This produces a lot of heat. Maybe the neighbouring ‘cell’ gets too hot and starts leaking its energy into the open. And so on. Once initiated, this process is difficult to halt, and has a tendency to burn up all in its path.
We’ll come back to that later.
The problem
Over time, as batteries are aged and overworked — charged, and discharged, and charged, and discharged — batteries don’t work like they did when they were young. They start to get a little out of shape and can no longer perform as well as in times past.
Why?
Well, these little ions of lithium which we pass back and forth between anode and cathode, as our battery is charged and discharged repeatedly, will not sit in this purgatorial state indefinitely. They start to bind with the material in the anode and the cathode. Less lithium ions are free to do our bidding and it becomes harder for those remaining ions to settle into those materials, what with the lithium-flavoured film which forms from these side reactions blocking their path. This process can, and is, measured by coulomb efficiency. The battery university has a nice article on the death of lithium-ion batteries.
Oh, and there are also these things called dendrites. They are the weeds of the battery world. They grow inside of the battery cells, pressing the fast-forward button on those reactions we talked about, and generally wreaking havoc on the battery insides.
As humans, and assholes, our natural instinct with things that are no longer immediately useful to us is to throw them away. Remember our friend, Mr. Thermal Runaway? Well, he’s going to have a field day being thrown into the landfill, basking in the tons and tons of shrapnel and debris thrown atop the battery pack. In case you didn’t get the message: bad idea.
Well, couldn’t we just pull the battery pack apart enough that thermal runaway isn’t so much of an issue, and then throw it away? Sure, but remember; we’re trying to avoid the consequences of our rare-metal supply running low.
We have a couple of options, which are less likely to incur a high death toll than simply throwing our battery packs away. What’s more, they can work in tandem:
Reuse: repurpose old batteries for less demanding applications
Like a retired Navy SEAL, a retired EV battery is usually not to be sniffed at. Plenty of life in the old dog yet. Unlike a retired Navy SEAL, an old battery (as far as I know) doesn’t dream of whittling away its senior years playing golf in a tropical resort (in fact, I have no idea what the average Navy SEAL’s retirement dreams are either).
We can repurpose EV battery packs for other use cases. Eventually, though, our trusty battery packs will be of little use even to the least demanding of applications. The withered carcass that remains must be dealt with.
Recycle: extract useful and costly components from spent battery packs
I’m starting to sound like an early 2000’s ad campaign.
You’ve probably ignored plenty of battery recycling points in your local supermarkets and charity shops. I’m not saying that your standard AA’s and AAA’s aren’t going to be a little troublesome, but we’re really playing in the big leagues with these large EV-sized battery packs. Our old friend thermal runaway is about to rear his ugly head (he might actually be rather beautiful when he’s not burning up everything in his path).
Recycling battery packs is tough. There are a lot of components which must be taken apart and separated before we can get our precious, precious metals out of the gloop that remains. What’s more, batteries come in many different forms — cylinders, pouches, prisms… Although the underlying chemistry is essentially the same, the differences in form pose a challenge to large-scale automation of recycling processes:- Dismantling EV battery packs is a relatively delicate process. If each manufacturer wants to stamp their own pack design into their product, and more so if they want to tweak that design on every vehicle iteration, the robotics programmers will never see the light of day. Of course, this problem will be solved — as all problems — given time.
Repair: can’t we ‘reset’ the battery back to its original state?
Ideally yes, of course. In practice, no. Not yet, at least — and probably not in time to make ignoring our problems a viable option. This would involve ridding our battery systems of any dendrites which have formed. Removing or reversing the process of film formation on the surfaces of our electrodes. Ensuring that we regain the same amount of free lithium ions. Etc…
Stop using elements in short supply…
Why not just stop using these rare-earth metals for powering such mass-produced products? Well, some folks are. Or at least they’re trying to — low cobalt / cobalt-free batteries are looking good. Alternatives to lithium are in the offing too (we’re looking at you, sodium). They’re just not very good — yet. That’s not to say that they won’t be. In the meantime, we still have problems.
Closing remarks
Progress in EV tech is great. But all of our environmental problems are not solved. Some conscious consideration and appreciation of where exactly we are on this journey, and where we need to be, should help to bridge differences in knowledge and opinion.
Maybe you already own an EV. If you don’t, you most likely will within 10 years. That’s great. Really, it is. It’s a huge leap in progress for us as a species working towards existing beyond the next few generations. There is still a long way to go. Conditions will worsen; Wars will be fought. Effort made now will not be wasted.
Cheers —
