Reincarnation for Lithium-IonIt's not because a battery pack isn't good enough for an electric or hybrid car anymore that it should go directly to a recycling plant. There are lots of potential secondary uses for batteries that can still hold more than half of their original charge. I've already written about how they could be used to store wind power to reduce the intermittency problem, but a new partnership between Nissan North-America, ABB, 4R Energy, and Sumitomo Corporation of America believes that used electric car batteries (Nissan LEAF ones, in this case) could be used for residential and commercial energy storage, even acting as emergency back-up during natural disasters like last year's earthquake and tsunami in Japan.
Electric car batteries have up to 70% capacity remaining after 10 years of use. This allows them to be used beyond the lifetime of the vehicle for applications, and smart grids can take advantage of their capacity to store intermittent renewable energy.
Innovative energy storage solutions are expected to become a key component of the smart grid, contributing to greater efficiency, reliability and performance. They will facilitate further integration of renewable energy sources, such as wind and solar, into the grid. The evaluation of Nissan batteries, through the partnership, will help determine their suitability for the power industry as a cost-effective energy storage solution. (source)
The partners plan to develop a LEAF battery storage prototype with a capacity of at least 50 kilowatt hours (kWh), enough to supply 15 average homes with electricity for two hours. I assume that if that works out well, they'll scale it up, possibly even up to the multi-megawatt-hour scale, which would make it really useful in emergencies and to store solar or wind power.