NONAQUEOUS ELECTROLYTE BATTERY AND MANUFACTURE OF SEALING PLATE THEREOF

摘要

A structure of an explosion-proof safety valve of a compact nonaqueous electrolyte battery, such as, a lithium ion secondary battery, which is thin and rectangular or has an elliptic cross section with a small sealing plate area, and manufacture of a sealing plate. By reliably actuating the explosion-proof valve with a simple structure and without sacrificing the capacity, the safety of the battery is to be ensured. An aperture upper edge portion of a metallic bottomed cell container and a peripheral edge portion of a metallic sealing plate are hermetically sealed by laser welding. A through-hole is provided at a center portion of the sealing plate, and a rivet which also functions as a terminal is clamped, hermetically sealed and fixed through a gasket. An exhaust hole is provided between the terminal and the peripheral edge portion of the sealing plate, and this exhaust hole is closed by a metal foil, thus providing the explosion-proof safety valve. With such a simple structure, the valve operates accurately to prevent fault. Also, this sealing plate is continuously manufactured in a hoop-like shape.