In the aftermath of the last year’s devastating Japanese earthquake and tsunami, more impetus has been given to the idea of turning electric cars -- and their battery packs -- into emergency backup power systems

But now a new project has been set up to take the idea of using electric car batteries to provide backup power one step further -- by building backup battery banks built entirely of Nissan Leaf battery packs. 

Announced yesterday, the collaboration between Nissan North America, power technology group ABB, 4R Energy and the Sumitomo Corporation of America aims to develop a prototype system that uses old Leaf battery packs to provide emergency power for 15 average homes for up to two hours. 

After ten years of use in a Nissan Leaf, the lithium-ion battery pack responsible for providing motive power to the car will have lost around 30 percent of its original 24 kilowatt-hour capacity. 

For the driver, that equates to lost range, and less performance than when the car was new. 

2011 Nissan Leaf SL

2011 Nissan Leaf SL

But while the remaining 16.8 kilowatt-hours or so may not be enough to provide useful power to an electric car, battery pack is still capable of storing charge.

Cheaper than recycling, placing used Leaf battery packs together in a larger backup battery array ensures that the lithium-ion battery packs remain useful for as long as possible. 

As well as provide power in a natural disaster, the backup battery arrays have the potential to reduce demand on the electrical utilities during peak demands, reducing brownouts. 

It will also ensure that battery packs stay out of landfills.

The idea of using large banks of batteries to supplement the power to the electricity grid isn’t new. In fact, many DIY electric car enthusiasts regularly recycle old lead acid battery packs from their home-built electric cars by using them to store electricity harvested from solar panels during the day so they can charge their cars up at night for free. 

2011 Nissan Leaf

2011 Nissan Leaf

However, the new project involving Nissan Leaf battery packs is the first one we’ve heard of which exclusively uses battery packs from a particular electric car. 

We’d love to see the project succeed, but can’t help but wonder if utility companies will be comfortable using unknown, repurposed battery packs to provide reliable backup power. 

It is more likely, unfortunately, that utility companies will favor brand-new lithium-ion cells in large arrays to ensure the systems remain completely predictable. 

Even if that happens, it’s still a win-win for electric cars: if demand for lithium-ion cells increases, economies of scale should help drive down the cost of electric car battery packs. 


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