LEAD-ACID BATTERY

PROBLEM TO BE SOLVED: To improve the life of a battery by rolling a current collector after casting. SOLUTION: A non-work current collector 1 manufactured by casting is rolled with a flat pressurization die a2. Thereafter, it is re-rolled with a pressurizing die b3 having engraved into a substantially triangular section to provide a worked current collector 4 having a substantially diamond sectional profile. The shape of the metal mold in the casting, the compression by the pressurization die a2 and the engraving pattern of the pressurization die b3 are changed, whereby a worked current collector 4 having a rolling ratio of 5-75% can be provided. The rolling ratio is represented by (A-B)/A×100%, wherein A is the thickness of the non-work current collector 1 and B is the thickness of the worked current collector 4. When this worked current collector 4 is used in a positive electrode, a long-lived battery can be obtained. Particularly, when the worked current collector 4 having a rolling ratio of 10-50% is used, and the life of the battery can be further extended.