Sanyo Electric Co., Ltd.

Reizo Maeda

Ikuo Yonezu

Katsuhiko Shinyama

Koji Nishio

Yoshinori Matsuura

Mitsuzo Nogami

Toshiyuki Nohma

Tadayoshi Tanaka

Mutsumi Yano

Mitsuzou Nogami

Yasuyuki Harada

Shin Fujitani

Mamoru Kimoto

Masao Inoue

Hiroshi Nakamura

Hiroshi Watanabe

Toshihiko Saito

Shigekazu Yasuoka

Mitsunori Tokuda

Syuichi Suzuki

Syuuichi Suzuki

A method of detecting battery degradation level detects charging and discharging current flow in the battery and determines battery degradation level (state of health, SOH) from the charging and discharging current. The method detects the battery degradation level (SOH) from the root-mean-square of the charging and discharging current flow (I) in the battery, which is designated effective current.

Method of detecting battery degradation level

A nickel electrode for an alkaline storage battery in which an active material mainly containing nickel hydroxide is applied to a porous sintered nickel substrate, wherein a layer containing at least one hydroxide of an element selected from a group consisting of Ca, Sr, Sc, Y, lanthanoid, and Bi is formed on a surface of the active material thus applied to the sintered nickel substrate, or between the sintered nickel substrate and the active material.

Nickel electrode for alkaline storage battery, method of producing nickel electrode for alkaline storage battery, and alkaline storage battery

Nickel electrode for alkali storage battery, method of producing nickel electrode for alkali storage battery, and alkali storage battery

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

In a hydrogen absorbing alloy electrode employed as a negative electrode of an alkaline storage battery, a covering layer containing at least one of metal elected from nickel and cobalt, and carbon particles is formed on a surface of the hydrogen absorbing alloy electrode or hydrogen absorbing alloy particles used in the hydrogen absorbing alloy electrode.

Hydrogen absorbing alloy for electrode, hydrogen absorbing alloy electrode and alkaline storage battery

A nickel electrode for alkaline secondary battery including a porous sintered nickel substrate loaded with a nickel hydroxide-based active material, the nickel electrode has a configuration wherein a surface portion of the active material loaded into the sintered nickel substrate is provided with a combination of a first coating layer of a suitable compound and a second coating layer of a suitable compound, or a coating layer of a compound of two or more suitable elements, or wherein the coating layer of two or more suitable elements is formed between the sintered nickel substrate and the active material.

Nickel electrodes for alkaline secondary battery and alkaline secondary batteries

In a hydrogen absorbing alloy electrode containing hydrogen absorbing alloy powder and a binding agent, employed as the binding agent is a copolymer of aromatic vinyl and at least one of acrylic ester and methacrylic acid ester, in which the total content of acrylic ester units and methacrylic acid ester units is in the range of 43 to 90% by weight of the whole copolymer, and the hydrogen absorbing alloy electrode is used as a negative electrode of a nickel-metal hydride battery.

Hydrogen absorbing alloy electrode and nickel-metal hydride battery

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 hydrogen absorbing alloy electrode is prepared by adding a binder to a hydrogen absorbing alloy powder and forming the mixture to a shape of an electrode, and the binder is partly or entirely made of poly N-vinyl acetamide, whereby higher high-rate discharge characteristics are obtained than conventionally.

Hydrogen absorbing alloy electrodes and nickel-metal hydride batteries using the same

In a non-sintered nickel electrode for an alkaline storage cell, a discharge capacity and cycle life are improved. This is achieved by employing, as an active material for the non-sintered electrode, coated nickel active material particles, each of the particle comprising a base particle composed of nickel hydroxide and a Co&mdash;P&mdash;A layer coated on the base particle comprising Co and P and an element A, where A is at least one element selected from the group consisting of Mn, Zn, Ni, Y, and Bi.

Non-sintered nickel electrode for alkaline storage cell, and alkaline storage cell utilizing the electrode

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

Alkaline storage battery and method for charging battery

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.

Growing community of inventors

Kasai, Japan

Reizo Maeda