RECTANGULAR LITHIUM SECONDARY BATTERY

摘要

A rectangular lithium secondary battery where excellent battery characteristics and safety can be achieved by preventing damage on a porous heat resistant layer. The rectangular lithium secondary battery has a rectangular battery can having a bottom, a sidewall, and an upper opening; an electrode group; a nonaqueous electrolyte; and a sealing plate covering the upper opening of the battery can containing the electrode group and the nonaqueous electrolyte. The electrode group consists of a positive electrode and a negative electrode, and a porous heat resistant layer and a separator that are interposed between the positive and negative electrodes. The sidewall of the battery can has two rectangular main flat portions facing each other, and the thickness A of the porous heat resistant layer and the thickness B at the main flat portions of the sidewall satisfy 0.003 <= A/B <= 0.05.