LEAD-ACID BATTERY

PROBLEM TO BE SOLVED: To suppress the disconnection of a joint part between a positive electrode current collecting lug and a positive electrode strap due to vibration in particular. SOLUTION: In the crystalline structure of a joint between the positive electrode current collecting lug and the positive electrode strap, a first region is formed which has a crystalline structure oriented in the longitudinal direction of the positive electrode current collecting ear. At the front end of the positive electrode current collecting lug, where the sizes of crystal grains in the thickness direction of the positive electrode current collecting lug are crystal grain sizes, a second region is formed which is a region ranging from the first region, which has an average crystal grain size larger than the average crystal grain size of the first region, and which has a crystalline structure aligned in the longitudinal direction of the positive electrode current collecting lug. Ranging from the second region, a third region is arranged which has a crystalline structure not oriented in a specific direction. COPYRIGHT: (C)2011,JPO&INPIT