PURPOSE: To improve the storage characteristic and leak-proof characteristic by using an alloy of aluminum and silicon carbide for a positive electrode case.
CONSTITUTION: The material of a positive electrode case 3 is made of an alloy of aluminum and silicon carbide. For example, the positive electrode case 3 is made of an alloy added with silicon carbide (SiC) 20 pts.wt. to aluminum, and an alloy sheet having an original thickness of 0.3mm is molded into a bottomed cylindrical shape having an outer diameter of 2.2mm, a height of 10.5mm, and a side thickness of 0.15mm by press machining for use. It is excellent in the tube producing property, and its mechanical strength is increased as compared with aluminum (elastic strength: 1.6 times, tensile strength, fatigue strength: 1.7 times). Therefore, when the opening section of the cell case 3 is sealed and caulked via a gasket 7 made of polypropylene.butadiene rubber, the mechanical strength is improved, the sealing performance of the cell is improved, and as a result the storage characteristic and leak-proof characteristic of the cell are improved.
MOMOSE KEIGO
MIZUTANI SEIICHI
KOGURE HARUO
