Toshiba Battery Co., Ltd.

Kouji Taguchi

Tomoyuki Ono

Kazuo Kojima

Hideaki Kitazume

Hideaki Kozawa

Hirofumi Yanagawa

Hideharu Suzuki

Kazuhiko Harada

A nickel-hydrogen secondary battery has a positive electrode including a positive electrode mixture which contains a nickel compound as a major component and which is supported on a collector sheet, a negative electrode including a negative electrode mixture which contains a hydrogen absorbing alloy as a major component, a binder and an electrically conductive material and which is supported on a collector sheet, the positive and negative electrodes being stacked up alternately or rolled up with a separator interposed therebetween to form an electrode group, and a battery case containing the electrode group together with an electrolyte, the battery case having an opening closed with a sealing plate which is provided with a positive electrode terminal, wherein the binder contains at least carboxylated styrene-butadiene copolymer latex, the conductive material contains metal flakes or short metal fibers, and an edge portion of the collector sheet of the negative electrode is electrically connected to the battery case via a collector plate welded to the edge portion of the collector sheet.

Nickel-hydrogen secondary cell

A rectangular nickel-metal hydride secondary cell permits improving the air-tightness and also permits preventing a metal case from being deformed in a step of folding an open end portion of the metal case. The rectangular nickel-metal hydride secondary cell, includes a rectangular cylindrical metal case having a bottom, an electrode group housed in the metal case, an alkali electrolyte contained in the metal case, a rectangular sealing plate mounted near the open end portion of the metal case. An insulating gasket is interposed in a compressed state between the inner wall near the open end of the metal case and the sealing plate. The metal case comprises a folded portion formed by inwardly folding the open end portion of the metal case and an inwardly projecting stepped portion formed along the inner surface of the metal case below the folded portion. The sealing plate is fixed to the metal case at the portion between the folded portion and the stepped portion of the metal case with the insulating gasket interposed therebetween, the folded portion at a corner portion of the open end portion of the metal case has an angle of 80.degree. to 100.degree.. Such a secondary cell can be formed by a process which includes charging-discharging cycles, an aging step, and a full charging step.

Method of manufacturing a nickel-metal hydride secondary cell

A rectangular nickel-metal hydride secondary cell permits improving the air-tightness and-also permits preventing a metal case from being deformed in the step of folding an open end portion of the metal case. The rectangular nickel-metal hydride secondary cell, comprising a rectangular cylindrical metal case having a bottom, an electrode group housed in the metal case, an alkali electrolyte contained in the metal case, a rectangular sealing plate mounted near the open end portion of the metal case; and an insulating gasket interposed in a compressed state between the inner wall near the open end of the metal case and the sealing plate, wherein the metal case comprises a folded portion formed by inwardly folding the open end portion of the metal case and an inwardly projecting stepped portion formed along the inner surface of the metal case below the folded portion, the sealing plate is fixed to the metal case at the portion between the folded portion and the stepped portion of the metal case with the insulating gasket interposed therebetween, the folded portion at a corner portion of the open end portion of the metal case has an angle of 80.degree. to 100.degree..

Method of making a rectangular nickel-metal hydride secondary cell

A rectangular nickel-metal hydride secondary cell permits improving the air-tightness and also permits preventing a metal case from being deformed in the step of folding an open end portion of the metal case. The rectangular nickel-metal hydride secondary cell, comprising a rectangular cylindrical metal case having a bottom, an electrode group housed in the metal case, an alkali electrolyte contained in the metal case, a rectangular sealing plate mounted near the open end portion of the metal case; and an insulating gasket interposed in a compressed state between the inner wall near the open end of the metal case and the sealing plate, wherein the metal case comprises a folded portion formed by inwardly folding the open end portion of the metal case and an inwardly projecting stepped portion formed along the inner surface of the metal case below the folded portion, the sealing plate is fixed to the metal case at the portion between the folded portion and the stepped portion of the metal case with the insulating gasket interposed therebetween, the folded portion at a corner portion of the open end portion of the metal case has an angle of 80.degree. to 100.degree..

Growing community of inventors

Yokohama, Japan

Kouji Taguchi