Other

Sanyo Electric Co., Ltd.

Fumiyoshi Yoshinari

Motoo Tadokoro

Atsushi Watanabe

Takashi Hasunuma

Katsuya Kawano

Kazuo Osaki

A hermetically sealed battery is provided, equipped with a opening sealing unitincluding a Positive Temperature Coefficient (PTC) element without reducing the volume of the outside can, and capable of preventing the generation of a large current in case a short circuit occurs as well as enhancing operational security. The opening sealing unitaccording to the invention comprises a bottom platefor closing the opening of the outside can, a positive electrode capforming a space for storing a pressure valve, said positive electrode cap being used as a terminal for the positive electrode, a resilient valvehaving a steel plateon the upper surface, a springand a PTC element ringdisposed on the flangein the positive electrode cap. An insulation gasketis mounted onto the periphery of the opening sealing unitto hermetically close the opening of the outside can

Hermetically sealed battery

A battery pack and a PTC device are provided that can be used safely under large current loads by increasing the area of the incorporated PTC layer so as to decrease its internal resistance. The battery pack has a plurality of unit cells ( ) placed side by side in parallel and the PTC device P to protect the unit cells ( ) from overcurrents. The PTC device P has a first electrode ( ) and a second electrode ( ) connected to the both surfaces of the PTC layer ( ). The PTC layer is formed to an outer shape that covers almost the entirety of the end surfaces of the two unit cells ( ) to which the first electrode ( ) and the second electrode ( ) are connected, and has through holes ( B) positioned against the end electrodes ( A) of the unit cells ( ). The first electrode ( ) and the second electrode ( ) connected to the both surfaces of the PTC layer ( ) are formed to an outer shape almost the same as the outer shape of the PTC layer ( ); and the first electrode ( ) and the second electrode ( ) are connected to the end electrodes ( A) of the unit cells ( ) at points where the through holes ( B) of the PTC layer ( ) are located.

Battery pack and PTC element incorporated in the battery pack

Growing community of inventors

Tokushima, Japan

Fumiyoshi Yoshinari