The development of the new type of VRLA battery for solar and wind power generation systems.

A tubular-type VRLA battery with granular silica has been developed. This new VRLA battery has some outstanding characteristics, such as long cycle-life, high energy efficiency or high reliability. This battery has a new electrolyte retainer, which is granular silica, filled between positive and negative plates, and also around plates. Because granular silica retainer can compress the active mass homogeneously and does not shrink even after much water loss during long period of operation, battery can perform these outstanding characteristics. Recently, these developed AGS (Absorptive Granular Silica) batteries have been introduced in the wind power generation systems and also photovoltaic power generation systems. As these power generation systems suffer quality of electric grid, such as frequency or voltage fluctuations. In order to prevent these problems, introduction of AGS battery with advanced characteristics is necessary. In 1999, 600 cells of 500Ah-2V (=600kWh) AGS batteries were introduced into the remote island in Okinawa, Japan for the 280kW wind power generation system of the Okinawa Electric Power CO.,LTD and they have been operating very well.