Los Angeles-based B2U (Battery Second Use) Storage Solutions is currently using 1,300 retired battery packs from Honda and Nissan electric vehicles (EVs) at its solar and energy storage facility in Lancaster, California.

With a storage capacity of 25 MWh, the Sierra hybrid solar and storage facility is interconnected directly to the grid, selling power and grid services into California’s wholesale power market. This deployment represents the world’s largest operational UL 9540-certified energy storage system utilizing second-life EV batteries. The system incorporates B2U’s patented EV Pack Storage (EPS) technology in which strings of retired battery packs are connected in parallel. Controllers drive the strings so that during charge and discharge cycles, weaker batteries with lower capacity do not limit the performance of stronger ones.

The 25 MWh of storage capacity at this facility is comprised of 1,300 second-life EV battery packs. Source: B2U

The company maintains that this approach enables the system to achieve efficient energy yield despite the variance in capacity inherent in second life batteries. Safety measures have also been implemented: to mitigate any potential hazards, battery packs are automatically disconnected if any component deviates from its operating specifications and design limits.

B2U has successfully tested GM Bolt and Tesla Model 3 battery packs with its EPS system, demonstrating the ability to be configured to operate with any EV battery.