East Japan Railway Company (JR East) developed the hybrid system with the diesel engine and the lithium-ion battery, and began operational service of the world' s first hybrid diesel railcar Ki-Ha E200 in July 2007. This hybrid system could decrease the negative environmental impact of the diesel railcar. The rechargeable lithium-ion battery is selected for the storage battery because of high power and energy density. The deterioration investigation of the storage battery was executed in September 2009 and it is suggested the longevity might be extended for several years from this investigation.
