Roughly two dozen LEAFs were destroyed as a result of the tsunami that devastated Japan in March. None of the LEAFs batteries were damaged, according to the New York Times.
LEAF batteries consist of four lithium-ion cells, packaged into modules, which are themselves packaged into the 660 pound battery packs. The pack itself is then encased in an airtight steel case. Now you might be getting a sense of why these things are so heavy – there is more packaging than chemistry going on here. Nissan has always been a very conservative company when it comes to safety. Nissan was the first Japanese automobile manufacturer to develop brake override technology – the capability to let the brakes override the gas if needed.
“Considering how they were tossed around and crushed, we think that is a very good indication of the safety performance of that vehicle,” said Bob Yakushi, the director of product safety for Nissan North America.
The Chevrolet Volt, recently involved in additional safety testing by the National Highway Traffic Safety Administration (NHTSA), has a steel tray with a plastic cover. According to a General Motors spokesperson, GM opted to use a non-conductive material for the cover. An odd decision, it seems to us, as crashes don’t discriminate as to which part of the battery casing (cover or tray) might come into contact with the body of the vehicle. In addition, the Volt uses liquid battery coolant which may have played a part. The LEAF needs no coolant. NHTSA has said that they have no safety concerns with vehicles other than the Volt. The upcoming Ford Focus Electric will have a battery encased in steel also.
Source: New York Times