Panasonic said Wednesday it’s aiming to improve lithium-ion battery energy density by 20% in the next eight years, which is great news for the car companies it supplies, like Tesla and Toyota. The patents it’s filed give an insight into how it thinks it can do that, which is some complicated chemistry.
According to a Reuters report, Panasonic Chief Technology Officer Shoichiro Watanabe said the 20% gain would be found in building batteries that can run at a higher voltage. Currently, Panasonic supplies car batteries to Tesla that have a voltage of 4.2 volts, Watanabe identified that if that could improve to 4.5 or 4.6 volts, then, “the whole world view in terms of what’s possible for EVs would change.”
That’s not a random number, but rather it’s based on Panasonic’s research. The company said that changing the additive mix in battery electrolytes and using single-crystal materials in the cathodes of batteries will make pushing the voltage higher possible.
This isn’t the first time Panasonic has thought about improving battery chemistry via additives. There’s a joint patent filed by Tesla and Panasonic specifically for additives in battery electrolytes. The patent was filed in April 2021 and is for an “improved battery system,” developed for lithium-ion tech.
“The improved systems include a nonaqueous electrolyte including one or more lithium salts, one or more nonaqueous solvents, and an additive or additive mixture comprising one or more operative additives selected from a group of disclosed compounds, including 3-aryl substituted 1,4,2- dioxazol-5-ones and 3-phenyl-1,3,2,4-dioxathiazole 2-oxide,” according to the patent. Those additives worked for 200 charge cycles at 95% expected performance, the filing said.
None of which is exactly something you’ll be making in your kitchen at home, but is something Panasonic may scale to meet Tesla’s needs. That patent only describes the battery’s tested durability at 4.3 volts, but obviously Panasonic has something else going that can take it further.
One of the biggest questions here is: Why improve lithium-ion? It’s not a good battery chemistry (electrodes suffer from degradation, thermal management is a big issue) it’s just the most widely-available, high (or high-enough) density formula we have on hand now. As battery technology develops, metal-air or even sodium-ion batteries are very likely to overtake lithium-ion, even though they’re currently in the development stages, while lithium-ion is getting close to the limit of what it can be expected to do.
By 2030, lithium-ion might not be the answer, so introducing improvements then might seem like pushing updates to Windows XP. But there’s a very important factor here that OEMs are building factories to make hundreds of gigawatt-hours of batteries a year. Repurposing them again to make a different type of battery, as well as junking everything we will have learned by then about how to get the most out of lithium-ion powered cars, isn’t likely to sit well with boards.
So: A 20% gain by 2030 might not be quite as much as the EV world is crying out for but it could be the best choice automakers can take by then, with what they’ve had to do now.
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