BMW Begins Solid-State Battery EV Testing

Auto Blog

23-05-2025

The sheet metal doesn't give much away, but this i7 M70 test mule is the Bavarian company's first roadworthy foray into the world of solid-state batteries
Bavaria brings better battery technology another step towards reality
Solid-state batteries are considered the inevitable future of EVs, but bringing them to market is slow work. One of Germany's most popular automakers is no stranger to putting in the legwork, as the i7 M70 you see before you is sporting batteries that have been in development since at least 2016. The automaker plans to road test the vehicle extensively on the streets of Munich.
Solid-state batteries under the sheet metal of the tester BMW i7
Engineers working on the solid-state battery i7
Front half of the i7 M70 with solid-state batteries
BMW leverages an investment and applies lessons learned in its first solid-state battery vehicle
Let's start with the how. Back in 2016, BMW began cooperating with battery manufacturing company Solid Power. In mid-2021, that commitment escalated, with the Bavarians (along with Ford) formally investing in Solid Power's Series B funding. At the end of 2022, the two grew even closer, as BMW kicked off a cell prototype production line with Solid Power's insight. Today, we feast our eyes on the result: a BMW i7 M70 fitted with solid-state batteries that were reportedly developed via the partnership.
Interestingly, the solid-state batteries here have more in common with the EVs BMW currently sells, rather than the upcoming Neue Klasse (NK) models. NK vehicles rely on cylindrical cells that are more tightly packed with no modules, whereas current BMW EVs use a prismatic design with modules. BMW calls this fifth-generation technology 'proven,' which is likely the reason it opted to use it over the much newer sixth-generation batteries. BMW says the i7 tester will hopefully give insight into two main areas: how to manage cell expansion as well as temperature and pressure conditioning.
Solid state batteries in BMW's battery facility.
Solid-state batteries are the next step for EVs, but progress needs to be made
The advantages of solid-state batteries are significant. They offer higher energy density and lower overall weight than the batteries in use today. That translates to better range and performance. Solid-state batteries are also more resistant to extreme temperatures, making them less of a fire risk and, at an even more basic level, improving perceived resiliency on the customer side. The biggest current downside is cost. The automaker quipped back in February that solid-state tech is simply too expensive to roll out, claiming customers wouldn't be willing to shell out the extra coin needed to make solid-state batteries a reality. At least, not for now. Around the same time, rival Mercedes-Benz said it was 'close' to putting solid-state batteries into production. Similarly, the Affalterbach-based automaker is testing an EQS fitted with 'semi-solid-state batteries.'
Engineer making adjustments on a laptop, i7 in the background —
Source: BMW
Final thoughts
Solid-state batteries may be the future, but there's still a lot of room for improvement when it comes to traditional lithium-ion tech. Look no further than BMW's own Neue Klasse cars, which are projected to offer as much as 500 miles of range or more on a full charge. Ultimately, it's unlikely we'll see a production-ready car powered by a solid-state battery this decade. After all, those product roadmaps have largely already been written. But with some manufacturers clearly looking to the future, it's reasonable to expect this niche to naturally evolve in the next ten years. Expect a low-batch or super-lux vehicle to pilot the tech at a high price, followed by a slow trickle down. Whether or not Mercedes will beat BMW to the punch is anyone's guess.