Mercedes-Benz Testing Solid-State Battery to Get EQS a 621-Mile Range

The Mercedes-Benz EQS is the all-electric version of the S-Class, the marque’s flagship product which also tends to get all the best that the automaker has to offer first. Soon, that might include a solid-state battery that gives the car a whopping 621 miles of range.

The lithium-metal solid-state battery is currently being tested by Mercedes, first last year in a lab in Stuttgart where Mercedes is based, and then, this month, on the road. Mercedes thinks the new battery technology will get 25 percent more range for the EQS, and will also catch fire less and even charge faster.

That’s compared to lithium-ion batteries, which Mercedes currently uses in the EQS and which use liquid electrolytes. The new batteries have solid electrolytes, and as a result can store more energy per unit mass, which means greater range, but also less weight.

Cars demand enormous amounts of power to move, and heavier cars demand even more power. Batteries also weigh a lot, and that presents something of a paradox: Bigger batteries provide more power but also weigh more and thus need more power. That’s in part why EV pickup trucks and semis haven’t quite caught on yet, because the power demands are so big.

Mercedes’s solid-state batteries promise to change that equation, at least a little bit. “Solid-state battery technology reduces the battery weight while improving cell safety,” Mercedes writes on its website.

When this technology might make it into a production car is anyone’s guess, though testing an EQS on the road is a big step forward for solid-state batteries, which have been talked about in the industry for over a decade. Toyota, for example, has been working on them, too, possibly in a new Lexus sports car. Tesla used to talk about solid-state batteries, but hasn’t for a while.

Mercedes, meanwhile, is trying to ensure that when the pendulum swings back to EVs, probably in a few years’ time, it’ll be ready with technology that might actually be a game-changer. The brand is already betting the future of its flagship product on it.