A pouch type secondary battery in which an electrode lead of the pouch type secondary battery and an electrode lead of an adjacent different pouch type secondary battery are welded together to construct a battery module is provided. The electrode lead of the pouch type secondary battery includes a length extended part so that, after cutting a welded part of the electrode leads of the pouch type secondary battery and the adjacent different pouch type secondary battery to form electrode leads of remaining length, the electrode leads of remaining length are welded together again. A battery module and method of reusing the battery module are also provided.