
EVs have a bit of a dirty secret. While they are way better for the environment than combustion cars, they aren’t exactly eco-friendly. The lithium-ion batteries that power them use cobalt, nickel and manganese, all of which have plenty of humanitarian and environmental problems, from heavy metal leaking to child slave labour. It also takes a vast amount of energy to refine these metals, and assemble them into a battery. But, there is a solution, the way more planet-friendly, a far cheaper sodium-ion battery, and luckily the world’s largest EV manufacturer is going to start producing them. So, the question has to be asked, will this revolutionise the EV world?
So, what are sodium-ion batteries. Well, it works in the same way as a lithium-ion battery, which shuttles ions of lithium between a cathode and anode to store and discharge energy. The only difference is what materials are used. Rather than lithium, it uses sodium, as the name suggests, but the anode and cathodes for sodium-ion are also far simpler, and don’t require heavy metals to improve energy density or charge times. In fact, some sodium-ion batteries don’t require an anode (in the case of CATL’s sodium-ion battery).
So, why are they so eco-friendly? Well, unlike lithium, it is super easy to refine sodium, as it is in salt. The same goes for the cathode and anode materials, they are easy to refine and assemble. What’s more, all of these materials can be easily mined and refined in the developed world, meaning very little risk of sparking humanitarian issues.
This light-footed impact on the planet translates into cost savings. A lithium-ion battery costs around $132 per kWh, but sodium-ion can cost as little as $40 per kWh, or 70% less! What’s more, a sodium-ion can charge from 10% to 80% in only 15 minutes, about twice as fast as many lithium-ion cells, and lasts almost twice as long with a lifespan of 3,000 cycles. They are also safer, as they don’t pose as much of a fire risk as lithium-ion. But they are less energy dense. A lithium-ion pack hovers around 220 Wh/kg and peaks at close to 300 Wh/kg. Meanwhile, a sodium-ion battery is up to 160 Wh/kg, with some extraordinary lab cells reaching 200 Wh/kg. That means a sodium-ion pack will weigh 40% more!-
You might think this energy density makes sodium-ion batteries near useless. But, as the battery constitutes a third of the cost of an EV, the price difference of the sodium-ion battery more than makes up for its lack of energy density. What’s more, its superfast charging ability and long life cycle make cheaper, shorter-range EVs actually practical to own.
This is why many EV manufacturers have been getting interested in sodium-ion batteries. It could allow them to sell sub $20,000 EVs with 250 miles of range and a sub 20-minute fast-charge time. Such an EV would sell like hotcakes!
But, while sodium-ion batteries have been around for years, they have only just started getting energy densities high enough to be useful. What’s more, while sodium-ion batteries are similar to lithium-ion, the manufacturing process is rather different. Both of these factors mean that it is taking a long time to bring sodium-ion batteries to market.
CATL announced their Sodium-ion battery last year, but it has yet to enter production. It is slated to have an energy density of 160 Wh/kg, a fast charge (10% to 80%) in 15 minutes, a lifecycle of 3,000 charges, and a price of $77 per kWh. However, once production has scaled, CATL has stated that the price could drop to $40 per kWh. This makes it cheaper, faster charging and longer lasting than Tesla’s “revolutionary” 4680 cells.
But it isn’t just CATL, the world’s largest EV maker and third-largest battery maker, BYD (yep, it isn’t Tesla) recently announced its sodium-ion battery, which is damn exciting, as they have a history of making incredible packs from less energy dense chemistries.
Take the BYD blade battery. This uses LFP cells rather than lithium-ion. Think of them as a half way house between sodium-ion and lithium-ion, as they have specs, costs and environmental damage levels between the two. By using clever packaging and a unique manufacturing process, they have made it incredibly energy dense, at 50% more energy dense than CATL’s LFP cells that Tesla uses, at a cost of only $85 per kWh, or about 20% cheaper per kWh than CATL’s LFP cells. This battery pack is so good that Tesla is actually using it in its EU built Model Ys, and BYD has used it to embarrass Tesla’s Model 3 with their Seal EV (click here to read more about that).
Sadly, we don’t yet know the specs of BYD’s sodium-ion battery. All we know is that it has signed a joint venture with another company to start production in the near future. But if they use the same techniques and designs used in the blade battery, their sodium-ion packs could be utterly incredible.
So, are we going to see sodium-ion packs go mainstream and welcome in an era of super cheap, far kinder to the planet, EV industry? Possibly. The motivations for CATL and BYD aren’t to produce more eco-friendly batteries, rather to get a cost advantage in the EV industry. And we don’t even know if they can do that with this technology, after all there might be some serious hiccups with their production, just as Tesla has had with the 4680. What’s more, while the materials used to make sodium-ion batteries can be far more eco-friendly than those for lithium-ion, it doesn’t mean that is CATL and BYD are sourcing their raw materials from sustainable or humane sources.
So, yes, there is a chance that in a few years, the EV industry will be flooded with affordable planet-friendly sodium-ion EVs. But a lot has to happen for that to be the case. CATL and BYD have to successfully scale production of these cells, which isn’t an easy task. Manufacturers have to choose these cells, and may even have to design and launch EVs specifically around them to get the most out of them. These models then have to be successful and sell well, which is not a given in the current EV market. Then after all of that, we have to hope that CATL and BYD source their materials correctly rather than cutting corners. This might seem like a long shot, but considering the demand for cheaper useable EVs and the mounting social pressure to ensure sustainable sourcing (see outrage over cobalt in Tesla batteries), I think this “long shot” is actually more likely to happen than not.
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Sources: Energy Storage News, NEI, Will Lockett, Notebook Check, Elecktrek, Royal Society Of Chemistry, Nature