NON-AQUEOUS ELECTROLYTE SECONDARY CELL

摘要

An extremely safe non-aqueous electrolyte secondary cell free of explosions and which can promptly release the internal pressure in case of rise in the inte rnal pressure. The non-aqueous electrolyte secondary cell has in its opening a cleava ge valve obtained on bonding a metal foil to the opening. In case of rise in the in ternal pressure, the cleavage valve is cleft to release the pressure. In this cell, a v alue K corresponding to the internal volume in the cell in cm3 divided by the area of t he opening in cm2 is set so that 40 ~ K ~ 350. By selecting the value K to a suitab le value, the cleavage valve is in operation when the internal pressure reaches a predetermined value to release the pressure. The metal foil is produced by, for example, a electro-forming method or a cladding method. Preferably, a fluorine-b ased water-proofing agent is coated on the foil surface.