BMW to Repurpose i3 Batteries for Home Energy Storage

BMW AG is partnering with Germany’s Beck Automation LLC on an energy storage system that can use used batteries from the carmaker’s i3 electric car for household purposes.

BMW announced the new program at this week’s Electric Vehicle Symposium in Montreal.

Described as an industry first, the system would allow i3 owners to unbolt the i3’s battery pack at the end of the vehicle’s life and install it into a Beck charging module. Customers also could purchase new or used i3 battery packs as they become available.

Using the i3’s 22-kWh or 33-kWh capacity lithium-ion batteries, the energy storage unit could be used as a back-up generator or to power appliances and recharge EVs and plug-in hybrid cars. BMW notes that a typical American home consumes between 15 kWh and 30 kWh of energy per day, which means the system could power in-home electronic devices for one to two days.

The battery can be charged off the power grid or via solar panels in homes equipped with such systems. Utilizing real-time readings, the system can measure the available energy supply and demand to determine the optimal time to charge or discharge the battery. The backup system includes a voltage converter and power electronics to manage the energy flow between the house interface and the battery.

BMW has sold 45,000 i3s worldwide since launching the tiny EV in 2013. It expects battery packs to retain most of their original capacity at the end of a vehicle’s life and have “many additional years” of service in secondary applications.

The company, which has been testing post-vehicle battery usage for several years, currently is evaluating batteries from its Mini E vehicles in applications at BMW’s offices in Mountain View, Calif.