CYLINDRICAL NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

摘要

PURPOSE:To provide a secondary battery having a long charge-discharge cycle life wherein the battery is a cylindrical nonaqueous electrolyte secondary battery consisting of a group of electrodes and a nonaqueous electrolyte sealed in a container wherein the group of the electrodes consist of a positive pole for supporting a positive pole active substance depolarizing mix on a collector and a negative pole using lithium as its active substance are rolled spirally while having a separator between them. CONSTITUTION:Bending of an electrode in the rolling center direction is prevented by increasing the thickness of the substrate of a positive pole collector in the first round of the rolling and the decrease of the battery discharging capacity due to the bending can be suppressed. Due to the spring-like toughness of the collector substrate itself whose thickness is increased, the group of spirally rolled electrodes are always pressed toward outside of the rolling from the center of the rolling. Consequently, dendrite precipitated on the negative pole at the time of charge is also pressed, so that it does not drop off from the negative pole. In other words, the decrease of discharge capacity due to dropping off of the dendrite can also be supressed.