It may look like an electric 7 Series in M Performance guise, but this i7 M70 is far more interesting. BMW has swapped out its standard battery pack to test a more advanced technology. No, it’s not the upcoming Gen6 round cells debuting in the Neue Klasse iX3. Instead, the full-size luxury sedan relies on Solid Power’s solid-state batteries to deliver a longer range.
BMW is testing the i7 M70 in Munich to evaluate how the battery behaves in real-world conditions. Although range figures aren’t disclosed, it’s safe to assume the engineers are aiming for significantly more than the EPA-rated 285 miles offered by the regular model. The longest-range i7 currently available in the U.S. is the eDrive50. It’s a rear-wheel-drive version capable of 314 miles on a single charge.
BMW claims Gen6 cylindrical cells offer a 20% increase in energy density, but solid-state batteries promise even greater benefits. These include a broader operating temperature range and improved safety, as EVs with ASSBs (all-solid-state batteries) are less prone to fire due to a reduced risk of thermal runaway.
ASSBs are also expected to be significantly lighter than current lithium-ion packs. However, one major obstacle remains: production costs. Earlier this year, BMW confirmed that solid-state battery technology remains prohibitively expensive. Consequently, it’s unlikely to be used in a production model this decade. Transferring those costs to customers would make the vehicles unreasonably expensive.
While working to lower these costs, BMW is putting this electric 7 Series through months of on-road testing in Germany. The i7 M70 prototype combines existing Gen5 construction with prismatic cell modules, alongside new modules containing solid-state cells with sulfide-based electrolytes. These are being developed by Solid Power with support from BMW’s in-house experts. The two companies have collaborated on ASSBs since 2016.
BMW made a strategic investment in Solid Power about four years ago. In late 2022, their partnership expanded to include a prototype solid-state battery production line at BMW’s Cell Manufacturing Competence Center (CMCC) in Parsdorf.
Until BMW EVs with solid-state batteries are viable, all Neue Klasse models are expected to offer at least 373 miles (600 kilometers) of range. Some could exceed 559 miles (900 kilometers), according to our sources. However, these figures are based on the more optimistic WLTP cycle; EPA estimates would likely be 10–15% lower or even worse.
Source: BMW
