Solid-state battery pioneer breaks energy density record to double current theoretical limit

One of the solid-state battery pioneers has announced a new energy density record of 824 Wh/kg. The previous record holder, Cherry, recently tipped that it has managed to craft a 600 Wh/kg solid-state battery scheduled to go into production in 2027.

While this is still 20% higher than the previous theoretical maximum thanks to the use of novel polymer electrolyte technology, it pales in comparison to WeLion’s invention that it says can bring 1,000 Wh/kg energy density, or double what current solid-state battery technologies rate for.

Companies like Samsung, CATL, or Toyota have all bragged about their plans to release solid-state batteries with the heretofore theoretical maximum of 500 Wh/kg commercially in 2027. Those would bring electric cars capable of traveling 750 miles on a charge with battery packs fitting in the same footprint as the current 300-mile batteries of the Tesla Model Y, for example.

WeLion already has 150 kWh packs with 95% solid electrolyte installed in NIO electric vehicles like the ET7 sedan that cover more than 600 miles on a charge. When its new energy density achievement makes it into a production-ready solid-state battery, the same car would have a range of over 1,000 miles. Such a battery pack would be prohibitively expensive, though, cautions WeLion’s chairman.

The battery with semi-solid electrolyte in the NIO ET7, for instance, costs as much as a whole EV, so NIO is only renting it out for longer summer trips at its swap stations. WeLion admits that the 1,000 Wh/kg solid-state electrolyte chemistry it developed in partnership with BASF isn’t suited for giant EV batteries, at least until it can be produced at scale. Robots like Tesla Optimus, however, where battery safety and energy density are of paramount importance, would be prime candidates for its new technology.

This jibes with the conclusion of the world’s largest battery market, CATL, and Tesla’s supplier, Panasonic, which are also of the opinion that solid-state batteries with high-energy density and high prices would initially be more suitable for drones and robots, not electric cars, unless they are positioned in the luxury segment.

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