Sealed rectangular battery and manufacturing method for the same

A sealed rectangular battery has a conductive battery case including an external casing (50) and a sealing cap (40). The external casing encloses a generator element (80) and is sealed by attaching the sealing cap using heat. The battery includes an electrode terminal (41) with an opposite polarity to the battery case, and a safety valve (42). The safety valve includes a cap (421) that is charged with the same polarity as the battery case and a valving element that covers a vent hole. The electrode terminal and safety valve are provided separately at different positions on the battery case. This construction is simpler than conventional batteries where the safety valve is integrally formed with an electrode terminal, which means that the electrode terminal can be miniaturized. This reduces the internal resistance of the battery. This slim battery also has improved internal resistance.