New 4680 Tesla Batteries vs. Solid-State Batteries

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The new 4680 Tesla batteries are big news, but it’s solid state batteries that have been tipped as the killer app for unlocking the potential of electric cars for years and years (and years). With lighter weight, greater efficiencies, and quicker charging times than li-ion batteries, solid-state tech is being widely hyped, even here on CleanTechnica! But you might wonder, is it really the promising technology so many claim? Gene Berdichevsky doesn’t think so — and, as the engineer in charge of the Tesla Roadster battery pack, you might want to listen to him.

In a recent white paper published by his company, Sila Nanotechnologies, Berdichevsky calls solid-state batteries a “false hope,” and doesn’t pull any punches in his critique of the solid state hype train. “While there are technical reasons why this technology appears to be the holy grail of batteries,” he writes, “the reality is that even if the technology works (and that is a big ‘if‘ after 40 years of development) the technology is unlikely to find more than niche opportunities in the market.”

40 Years of Solid State Promises

If you’re like me, that comment about “40 years of development” got your attention. I know, for example, that I only heard the term “solid state battery” relatively recently — but I followed up Berdichevsky’s claim with a quick Google search and very quickly found research from Exxon (!?) and Duracell dating back to 1978 and 1981, respectively. That was based on this paragraph in the white paper: “Calling the technology ‘solid state’ doesn’t tell the real story — the reason to use ‘solid state’, refers to replacing the electrolyte which in conventional Li-ion is a liquid, with a solid. The reason to do this is to enable the use of a lithium metal anode that would replace the graphite anode entirely. A better name would be ‘lithium metal anode’ technology, which has a long ~40 year history of major technical and commercial challenges pre-dating conventional Li-ion.”

One such paper I found that chronicled some of that “lithium metal anode” development was titled “Brief History of Early Lithium-Battery Development” and authored by Mogalahalli V. Reddy, Alain Mauger, Christian M. Julien, Andrea Paolella, and Karim Zaghib. It is freely available for download at this MDPI link. It’s densely written and packed with jargon, but the table below proves out the “40 years” claim nicely, I thought.

Table courtesy MDPI.

Berdichevsky also takes issue with solid state supporters’ claim that a solid-state battery will be immune to fires. As part of a rundown of myriad technical issues that a commercially viable solid-metal anode technology has to overcome, he writes that, “There are many technical reasons to doubt that after 40 years of unsuccessful lithium metal anode development, something is fundamentally different this time, other than the ‘solid state’ branding. There is a myriad of technical challenges to overcome, starting with the risk of lithium dendrite plating. Lithium, like other metals, has a property that causes it to attach to high spots rather than in low spots when plating into an electrode film. This leads to the building of lithium spikes (dendrites) on the anode that pierce the separator, short circuit to the cathode, and cause catastrophic thermal runaway (fire) of the battery.”

In other words, undetected dendrites piercing a protective material layer and shorting out a battery does not seem to be an issue that is unique to li-ion pastes, as has been presented elsewhere.

What’s more, Berdichevsky’s is not the only detracting voice when it comes to solid state’s chances. “As soon as we think we have found a convincing way to scale up solid state, we’ll look at it,” an unnamed European auto exec told Politico, before adding, “we are not going to wait for something magical to happen.”

So, solid state has promise — but it also has decades of research behind it and unsolved technical issues that have prevented its widespread adoption. And, it should be noted, that’s despite the efforts of Exxon, Duracell, Toshiba, Sony, and others. Do we really think that Exxon solved the problem, then shelved it? What about Duracell? Even if you have maximum tin-hat protection and you’re selling yourself on the idea that of course Exxon and Duracell would suppress this tech to be able to keep selling what they’ve always been selling, what about Toshiba? What about Sony? Is there a scenario where Sony cracks the solid-state battery enigma and comes to market with a truly tech-forward autonomous EV before Rivian, Lucid, or even Ford?

Finally, if any of that was really the way forward, why has Elon Musk decided that the best path for his car company isn’t solid state, and focused instead on the new 4680 Tesla batteries?

4680 Tesla Batteries

Image courtesy Panasonic.

Developed in concert with its Gigafactory partner, Panasonic, the new 4680 battery cell is significantly beefier than the more familiar, “AA-style” li-ion that Tesla has been using successfully up to now. In terms of EV breakthroughs, though, they’re much more than “bigger.” These new Tesla batteries are a quantum leap forward, offering nearly five times the energy storage at just half the cost of Tesla’s already industry-leading battery tech. (Note that there may contain five times more energy, but they are also larger — they are not five times more energy dense.)

As if that wasn’t enough to get excited about, Tesla claims that the 4680 cell will help to enable a “100-fold increase in battery production” by the year 2030, thanks in part to the new battery type’s cylindrical architecture. That’s worth noting, too, because Tesla is one of the only car manufacturers using a cylindrical battery type. GM and others are using rectangular “packs” or “blades.”

GM Ultium battery, courtesy of GM.

That advantage is two-fold. First, it means that Tesla will almost exclusively benefit from the new 4680 cells (at least, initially). Second, it means that the existing Gigafactory infrastructure will be able to switch to the new battery type more easily than the “blade type” manufacturers. In a world where inventory shortages and high consumer demand are driving prices sky-high, those are hugely significant advantages!

4680 Tesla Batteries v. Solid State

So, will solid-state batteries ever come to market — especially in the face of the renewed competition and market realities it faces in Tesla and Panasonic? Nobody asked me, but I think the answer is: no, not even a little.

Solid-state batteries are not coming, and the new 4680 Tesla batteries are going to be just enough to keep that trillion-dollar valuation blasting to the moon. But, hey, that’s just me. What do you guys think? Watch this last comparison video from the guys at TechArchives compare the theoretical promise of solid-state batteries with the “ready now” power of the 4680 Tesla batteries, and then scroll on down to the comments section at the bottom of the page and give us your take. Enjoy!

Sources | Images: MDPI, Sila Nano, TechArchives, WSJ.

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