LITHIUM SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a lithium secondary battery which can secure safety by controlling an electric corrosion of a battery case even at a time of over-discharge and a short circuit.

SOLUTION: A lithium ion secondary battery is composed of a battery can which is served as a negative electrode outer terminal and made of a nickel plated carbon steel and a group of electrodes of which positive/negative electrode plates are wound around a separator are housed in the above battery can. A negative electrode tab extended from the negative electrode plate is welded with an outer circumference of a negative electrode current collector ring placed below the group of electrodes. Below the negative electrode current collector ring, a negative electrode lead plate made of zinc which connects electrically the negative electrode plate with a battery can is welded and the negative lead plate is fixed with an inner bottom of the battery can by a resistance welding. An oxidation reduction potential of the negative electrode lead plate is set lower than that of the battery can. Even if a battery voltage becomes 0V due to a melting of the negative electrode lead plate, a negative electrode potential becomes lower than the oxidation reduction potential of the battery can.

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