Sanyo Electric Co., Ltd.

Takuma Morishita

Hironori Marubayashi

Shigeki Fujii

Masatoshi Takahashi

Satoshi Yoshida

Kazuro Moriwaki

Kensuke Nakatani

Yoshihiro Tobita

Yosihiro Tobita

Ryo Kashimura

A sealed cell having a safety mechanism is provided. The safety mechanism has a non-resealable valve structure formed in a sealing plate that seals the cell. The valve structure is broken as soon as the internal pressure reaches or exceeds a predetermined value so as to permit the internal gas to be released outside. The valve structure has at least one dome protruding toward the interior of the cell, which in turn has at the periphery thereof a break groove for facilitating the breakage of the valve structure. This makes the valve structure highly responsive to the internal pressure and causes to form a break-opened orifice of a sufficient area at the time of operation in response to the increased internal pressure. The valve structure is not unnecessarily broken by the impacts of, for example, dropping. As a result, the safety of the sealed cell is significantly improved.

Sealed cell having non-resealable safety valve

A cell according to the present invention comprises a positive electrode, a negative electrode, an electrolyte solution, and an outer casing, wherein the outer casing comprises a valve platehaving a thickness, an annular-shaped break grooveformed on the valve plate, and one or more of break aiding groovesin the inner area of the break groove, and wherein the break aiding groove comprises such configurations that remaining thickness of the valve plate at the break aiding groove is thicker than remaining thickness of the valve plate at the break groove, and at least one end of the break aiding groove is connected with the break groove. In a cell provided with a valve plate which is a safety valvecomprising the break groove and the break aiding groove, the safety valve operates smoothly and releases a gas inside the cell quickly, and resistance to dropping impact is improved.

Cell safety valve and cell having same

Cell safety valve and method for manufacturing the same

A cell has an outer can made from either aluminum or an aluminum alloy, and a lead plate for current-utilization. The lead plate for current-utilization is welded to the outer surface of the outer can and further welded to a lead plate for connection which is connected with the protective circuit of the cell. This construction makes it possible to avoid directly connecting the outer can with the lead plate for connection. Consequently, the lead plate for connection can be resistance-welded, so that the protective circuit is prevented form being electrified. As a result, the reliability of the protective circuit is improved, as compared with the case where the lead plate for connection is laser-welded.

Cell which secures the reliability of a protective circuit

Growing community of inventors

Sumoto, Japan

Takuma Morishita