Sanyo Electric Co., Ltd.

Mitsuzo Nogami

Koji Nishio

Ikuo Yonezu

Yoshinori Matsuura

Katsuhiko Shinyama

Reizo Maeda

Mamoru Kimoto

Mutsumi Yano

Nobuyuki Higashiyama

Toshihiko Saito

Nobuhiro Furukawa

Teruhiko Imoto

Motoo Tadokoro

Seiji Kameoka

Masao Inoue

Mitsunori Tokuda

Yoshito Chikano

Shin Fujitani

Hiroshi Nakamura

Hiroshi Watanabe

Naoya Nakanishi

Shigekazu Yasuoka

Takahiro Isono

Hideyuki Inomata

Yasushi Kuroda

Kazuro Moriwaki

Kousuke Satoguchi

Kenji Inoue

Syuuichi Suzuki

A method of manufacturing a metal hydride alkaline storage cell includes a first step of preparing a negative electrode by applying a paste containing hydrogen absorbing alloy powder onto a substrate; and a second step of placing the negative electrode and a positive electrode into a cell can with disposing separator therebetween, and thereafter pouring an electrolyte into the cell can. Into the paste or the electrolyte, a catalytic metal compound that has a proportion of 0.1 to 2.5 wt. % based on the weight of the hydrogen-absorbing alloy powder and that is soluble in the electrolyte is added. Consequently, the catalytic action of the metal is fully utilized by this method that dots a catalytic metal or metal compound on the alloy surface, and thereby the inner pressure characteristic (high-rate charge characteristic) of a cell is improved.

Manufacturing method of metal hydride alkaline storage cell

A metal hydride alkaline storage cell of the present invention comprises a positive electrode, a separator impregnated with an electrolyte, and a negative electrode comprising hydrogen-absorbing alloy powder. On the surface of the hydrogen-absorbing alloy powder, there is formed a layer of hydrogen-absorbing alloy oxide, and on the layer of the oxide, there is dotted a catalytic metal or metal compound formed in a granular state by adding a substance soluble in the electrolyte. The substance is selected from the group consisting of a metal fluoride, a metal chloride, a metal iodide, and a metal sulfide. The proportion of the metal fluoride, the metal chloride, the metal iodide, or the metal sulfide in adding, is restricted within the range of from 0.1 to 2.5 wt. % based on the weight of hydrogen-absorbing alloy powder. When the layer of the hydrogen-absorbing alloy oxide is formed on the surface of the hydrogen-absorbing alloy powder, the reaction area on the surface of the hydrogen-absorbing alloy is increased due to the roughness of the layer. Consequently, the catalytic action of the metal is fully utilized by dotting a catalytic metal or metal compound on the alloy surface, and thereby the inner pressure characteristic (high-rate charge characteristic) of a cell is improved.

Metal hydride alkaline storage cell and manufacturing method thereof

The invention provides a hydrogen absorbing alloy electrode obtained by the step P of preparing a hydrogen absorbing alloy powder containing cobalt and nickel, the step P of subjecting the surfaces of the alloy particles to a reduction treatment with high-temperature hydrogen by holding the powder in a high-temperature hydrogen atmosphere under the conditions of temperature, pressure and time sufficient to reduce oxides formed in a surface layer portion of each of the alloy particles, not melting the alloy particles and not permitting the alloy particles to absorb hydrogen, the step P of treating the resulting powder with an acid or alkali by immersing the powder in an acid or alkaline aqueous solution, followed by suction filtration, washing with water and drying, and the step P of applying the resulting power to an electrically conductive substrate and shaping the substrate in the form of the electrode. The electrode thus provided has higher activity than conventionally.

Hydrogen absorbing alloy powder and process for producing same

In a nickel-metal hydride storage cell, deterioration of a cell capacity at high temperature and degradation of a cycle characteristic are suppressed. The nickel-metal hydride storage cell of the invention comprises in a cell case, a positive electrode comprising a positive electrode active material composed mainly of nickel hydroxide powder, a negative electrode comprising a negative electrode active material composed mainly of hydrogen-absorbing alloy powder, and a separator interposed between the positive and negative electrodes and impregnated with an electrolyte, the nickel-metal hydride storage cell characterized in that the negative electrode active material comprises a copper compound, the positive electrode comprises an aggregate of coated particles each in which a coating layer comprising a sodium-containing cobalt compound is formed on a surface of a nickel hydroxide particle, and the positive electrode active material is such that an oxide or hydroxide of one of bismuth, calcium, ytterbium, manganese, copper, scandium, and zirconium, is added to the aggregate of coated particles.

Nickel-hydrogen storage battery

A lithium secondary cell is disclosed in which a positive electrode plate and a negative electrode plate are spirally wound with a sheet of separator interposed therebetween. A plurality of positive electrode current collector tabs are attached to the positive electrode plate so that an interval is formed between the positive electrode current collector tabs in a longitudinal direction of the positive electrode plate, and a plurality of negative electrode current collector tabs are attached to the negative electrode plate so that an interval is formed between the plurality of the negative electrode current collector tabs in a longitudinal direction of the negative electrode plate. In a state of the positive electrode plate and negative electrode plate being wound together, the positive electrode current collector tabs and the negative electrode current collector tabs are so disposed as to face each other with the separator interposed therebetween.

Spirally-wound lithium secondary cell having a plurality of current collector tabs and method of manufacture

A metal hydride alkaline storage cell of the present invention comprises a positive electrode, a separator impregnated with an electrolyte, and a negative electrode comprising hydrogen-absorbing alloy powder. On the surface of the hydrogen-absorbing alloy powder, there is formed a layer of hydrogen-absorbing alloy oxide, and on the layer of the oxide, there is dotted a catalytic metal formed in a granular state by adding a substance soluble in the electrolyte. The substance is selected from the group consisting of a metal fluoride, a metal iodide, and a metal sulfide. The proportion of the metal fluoride, the metal iodide, or the metal sulfide in adding is restricted within the range of from 0.1 to 2.5 wt. % based on the weight of hydrogen-absorbing alloy powder. When the layer of the hydrogen-absorbing alloy oxide is formed on the surface of the hydrogen-absorbing alloy powder, the reaction area on the surface of the hydrogen-absorbing alloy is increased due to the roughness of the layer. Consequently, the catalytic action of the metal is fully utilized by dotting a catalytic metal on the alloy surface, and thereby the inner pressure characteristic high-rate charge characteristic) of a cell is improved.

Metal hydride alkaline storage cell

The present electrode is fabricated by coating a conductive substrate with a paste including a hydrogen-absorbing alloy, a binder and a carbon material and sintering the conductive substrate coated with the paste under vacuum or in an atmosphere of a non-oxidizing gas. In this electrode, the carbon material works as a reducing agent so as to suppress oxidation of the hydrogen-absorbing alloy during the sintering, and therefore, the electrode exhibits large oxygen absorbing power in over-charge. Furthermore, the present battery uses, as a negative electrode, the sintered hydrogen-absorbing alloy electrode exhibiting large oxygen absorbing power in over-charge, and hence attains high reliability because increase of the pressure within the battery is minimal.

Sintered hydrogen storage alloy electrode and nickel-hydrogen storage battery

The invention provides a hydrogen absorbing alloy electrode obtained by the step P,of preparing a hydrogen absorbing alloy powder containing cobalt and nickel, the step P,of subjecting the surfaces of the alloy particles to a reduction treatment with high-temperature hydrogen by holding the powder in a high-temperature hydrogen atmosphere under the conditions of temperature, pressure and time sufficient to reduce oxides formed in a surface layer portion of each of the alloy particles, not melting the alloy particles and not permitting the alloy particles to absorb hydrogen, the step P,of treating the resulting powder with an acid or alkali by immersing the powder in an acid or alkaline aqueous solution, followed by suction filtration, washing with water and drying, and the step P,of applying the resulting power to an electrically conductive substrate and shaping the substrate in the form of the electrode. The electrode thus provided has higher activity than conventionally.

Hydrogen storage alloy powder and method of manufacturing the same

The hydrogen-absorbing alloy electrode for alkaline storage batteries according to the invention comprises a hydrogen absorbing alloy powder prepared by grinding a strip of hydrogen absorbing alloy produced by solidifying a molten alloy by a roll method and satisfying the following relations:

Hydrogen-absorbing alloy electrode for alkaline storage batteries

In the non-sintered nickel electrode for an alkaline storage battery according to the present invention, the active material powder is made up of composite particles, each comprising a nickel hydroxide-containing core particle and a shell layer coating the nickel hydroxide-containing core particle, the shell layer containing a bismuth-containing compound, or is made up of composite particles, each comprising a nickel hydroxide-containing core particle, an inner shell layer coating the nickel hydroxide-containing core particle and an outer shell layer coating the inner shell layer, the inner shell layer containing a bismuth-containing compound and the outer shell layer containing cobalt metal, cobalt monoxide, cobalt hydroxide, cobalt oxyhydroxide or a sodium-containing cobalt compound prepared by adding an aqueous solution of sodium hydroxide to cobalt metal, cobalt monoxide, cobalt hydroxide or cobalt oxyhydroxide to obtain a mixture and heat-treating the mixture in the presence of oxygen. Provided is a non-sintered nickel electrode for an alkaline storage battery, having a high active material utilization rate not only when charged at normal temperatures but also when charged at high temperatures, and having good charge-discharge cycle characteristics.

Non-sintered nickel electrode for alkaline storage battery

A conductive agent for use in alkaline storage batteries in accordance with one aspect of the present invention contains 0.1 to 10% by weight sodium. This sodium content results from cobalt or a cobalt compound, to which an aqueous solution of sodium hydroxide is added and heated to 50 to 200.degree. C. A non-sintered nickel electrode for use in alkaline storage batteries is also proposed. In this electrode, the aforesaid conductive agent in accordance with the present invention is added to a pulverulent active material consisting of grains of nickel hydroxide or grains mainly constituted by nickel hydroxide such that 1 to 20 parts by weight of the conductive agent is added to 100 parts by weight nickel hydroxide contained in the pulverulent active material. Another non-sintered nickel electrode for use in alkaline storage batteries is also proposed. In this electrode, an active material takes the form of composite particles consisting of grains of nickel hydroxide or grains mainly constituted by nickel hydroxide, each of which has a surface formed with an electric conduction layer consisting of a cobalt compound containing 0.1 to 10% by weight sodium.

Conductive agent and non-sintered nickel electrode for alkaline storage

In the non-sintered nickel electrode for an alkaline storage battery according to the invention, a yttrium metal powder and/or a yttrium compound powder has been added to a particulate active material comprising composite particles each consisting of a nickel hydroxide core and a sodium-doped cobalt compound shell. Because the yttrium metal powder and/or yttrium compound powder inhibits the diffusion of cobalt into the nickel hydroxide core, the non-sintered nickel electrode of the invention exhibits a high utilization efficiency not only in an initial phase of charge-discharge cycling but over a long time of use. Moreover, because the yttrium metal powder and/or yttrium compound powder enhances the oxygen overpotential, the non-sintered nickel electrode for an alkaline storage battery according to the invention shows very satisfactory charge characteristics particularly at high temperatures.

Non-sintered nickel electrode for alkaline storage battery, alkaline

An non-sintered nickel electrode of alkaline batteries uses an active material powder which comprises composite particles comprising nickel hydroxide particles or solid solution particles consisting essentially of nickel hydroxide the surface of which is covered with a mixed crystal of cobalt hydroxide and the hydroxide of at least one metal (M) selected from the group consisting of aluminum, magnesium, indium and zinc. With this electrode, the cobalt hydroxide, which covers as a component of the mixed crystal the surface of the nickel hydroxide particles, minimally diffuses into them. Alkaline batteries using this electrode as positive electrode can therefore maintain, for a long period of time of charge-discharge cycles, the function of the cobalt hydroxide of increasing the conductivity of the electrode, thereby suppressing decrease in the discharge capacity in the course of charge-discharge cycles.

Process for producing non-sintered nickel electrode for alkaline battery

A non-sintered nickel electrode for use in alkaline storage cells includes an active material comprising a solid solution of nickel hydroxide mixed with manganese, the solid solution further incorporating one or more elements selected from a group consisting of cobalt, cadmium, calcium and magnesium; an active material comprising a solid solution of nickel hydroxide mixed with manganese and zinc, the solid solution further incorporating one or more elements selected from a group consisting of cobalt, cadmium, calcium and magnesium; or an active material comprising nickel hydroxide with manganese added thereto, some of which manganese is incorporated in a solid solution of nickel hydroxide and the rest of which manganese exists as liberated from the solid solution of nickel hydroxide.

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Itano-gun, Japan

Mitsuzo Nogami