Development of a long life 35 Ah capacity VRLA battery for load-leveling applications

A load-leveling (LL) system is needed for the effective use of electric power to preserve the environment in Japan. Although the valve regulated lead-acid (VRLA) battery is considered to be one of the suitable candidates, high requirements of long cycle life such as 2000 cycles or a calendar life of 7 years needed to be solved. We are currently developing a new VRLA battery for this application, and have succeeded in achieving over 2000 cycles with a 35 Ah class VRLA battery. It was confirmed by the detailed investigation after a cycling test of the battery that this cycle performance was achieved by improving the charge acceptance of the negative plate, avoiding the grid corrosion by applying an optimized charge condition.