Since 1992 the Lithium Battery Energy Storage Technology Research Association (LIBES) has been conducting a 10-year research and development project, ‘Development of the Dispersed-type Battery Energy Storage Technology’, on two types of batteries, an electric vehicle (EV) application type and a stationary type for a home-use energy storage system for load leveling. After the first interim evaluation in 1995, the work load of the battery developers in LIBES was divided into the following two groups: one is the group for the development of large-scale cells and battery modules with four approaches; and the other is the group for the development of next-generation battery technologies including lithium polymer battery technology. The aim of the research and development of lithium polymer battery technology in LIBES is to develop the solid-state lithium polymer battery using carbon material as the anode. Our laboratory has developed and improved a random copolymer of ethylene oxide and propylene oxide (SPE(B)) as one of the candidate polymer electrolytes.