To provide a lead acid battery stably which is highly durable against rough roads even when the deadweight of its electrode plate group is increased in order to improve volumetric efficiency and extend life.
In the lead acid battery, a plurality of electrode plate groups with the cathode and anode opposed via a separator are housed in respective cell chambers of a battery case made of resin which is divided into a plurality of cell chambers by a partition plate in such a way that the partition plate and the cathode and anode are parallel to each other, where different poles of adjacent electrode plate groups are connected together in series with a lead component and the poles among electrode plate groups at opposite ends which are not connected with the lead component have pole columns connected thereto. A ratio T/W of the thickness Tmm of an outer wall on short side face side parallel to the partition plate among outer walls of the battery case to the weight Wkg of the electrode plate groups is made to be 2.2 mm/kg or more.
SHIMODA KAZUHIKO
SUGIE KAZUHIRO
HORIE SHOJI
Daisuke Nagano
Kentaro Fujii