Sanyo Electric Co., Ltd.

Other

Akifumi Yamawaki

Motoo Tadokoro

Yoshitaka Baba

Takeo Hamamatsu

Shinsuke Nakahori

Masao Takee

Tadashi Ise

Takayuki Yano

A porous metal material was filled with an active material slurry, dried, and then rolled to a predetermined thickness. This rolling causes pores formed by a network skeleton to be stretched in the rolling direction (direction represented by the arrow in FIG. ( )) to form pores having a shape similar to ellipsoid or deformed ellipsoid having a long axis. Subsequently, the porous metal material was cut in such an arrangement that the longitudinal direction of the pores having a shape similar to ellipsoid or deformed ellipsoid coincides with the crosswise direction of the electrode plate, and then subjected to roller treatment through a series of rollers in the longitudinal direction of the electrode plate. This roller treatment causes numerous cracks to be formed at a very small pitch in the direction parallel to the rolling direction as shown diagrammatically in FIG. ( ).

Alkaline storage battery and process for the production thereof

A alkali storage cell includes a non-sintered type nickel electrode which includes a highly efficient nickel hydroxide active material and which causes no capacity decrease during an over-discharge operation. The nickel electrode contains an active material composed of nickel hydroxide, a solid solution of at least one of zinc, cadmium, magnesium, and calcium which are added to the nickel hydroxide, and cobalt compound layers which are formed over the surfaces of particles of the nickel hydroxide. The cobalt compound layers have an oxidation number of larger than 2 and a disordered crystal structure. Such an active material can be manufactured by mixing nickel hydroxide powder containing a solid solution of at least one of zinc, cadmium, magnesium, and calcium with either metallic cobalt or a cobalt compound, and subjecting the mixture to heat treatment in the presence of oxygen and alkali. Another production method is to precipitate a cobalt compound over the surfaces of the nickel hydroxide powder containing a solid solution of at least one of zinc, cadmium, magnesium, and calcium so as to form cobalt compound layers, before subjecting it to the heat treatment in the same conditions.

NON-SINTERED NICKEL ELECTRODE WITH EXCELLENT OVER-DISCHARGE CHARACTERISTICS, AN ALKALINE STORAGE CELL HAVING THE NON-SINTERED NICKEL ELECTRODE, AND A MANUFACTURING METHOD OF THE NON-SINTERED NICKEL ELECTRODE

Nickel-metal hydride storage cell having a high capacity and an excellent cycle characteristic and manufacturing

A belt-shaped spongelike organic high polymer sheet is subjected to stretching forces in the longitudinal and lateral directions so as to transform the approximately spindle-shaped organic high polymer units which compose the organic high polymer sheet. After this, a metal is put into voids inside the organic high polymer sheet. Then, the organic high polymer is eliminated by baking it, and the metal is sintered. As a result, a spongelike metal substrate is completed whose carbon content is 0.5% by weight or less and whose metallic lattices have a longer length/shorter length ratio of 1.7 or below. The spongelike metal substrate is filled with electrode active material to form an electrode, which is combined with a counter electrode and a separator, and coiled in the direction of the longer lengths of the lattices to form a coiled electrode assembly. The electrode assembly is used to manufacture an alkali storage cell.

Alkali storage cell employing a spongelike metal substrate

In a method of manufacturing a nickel active material, nickel hydroxide particles coated with cobalt hydroxide are put on the mesh disk 4 of the fluidized granulator 1. Then, hot air is continuously supplied from outside through the hot air inlet 5, while air inside the fluidized granulator 5 is continuously emitted through the air outlet 8. At the same time, the nickel hydroxide particles are stirred with the stirring fan 3 and further dispersed by a hot air current. In this condition, an alkali aqueous solution is sprayed on the nickel hydroxide particles through the spray nozzle 7 by the pump 9. After the spray, the nickel hydroxide particles are further stirred in hot air so as to complete an alkali heat treatment.

Manufacturing method of an active material suitable for non-sintered

A nickel active material for an alkali storage cell whose surface is covered with a cobalt compound, wherein the diffusion and permeation into the nickel hydroxide mother particles of cobalt compound during excessive discharging, which act to reduce the active material efficiency and the excessive discharging characteristics, are prevented. This is achieved by having a covering layer, including one or more of the following metal compounds; an aluminum compound, a magnesium compound, an indium compound and a zinc compound, in addition to a cobalt compound, formed on the surface of a mother particle of nickel hydroxide, and by heat treating the covered mother particles in the presence of alkali and oxygen so as to convert the cobalt compound into a compound of cobalt where an oxidization number of cobalt is greater than 2.

Nickel active material for use in alkali storage cells and its

Non-sintered nickel electrode with excellent over-discharge

Fine-grained nickel electrode active material, each of which contributing to electrode reaction; production method of the fine-grained nickel electrode active material; and a nickel alkali storage cell of high capacity which is excellent in over discharge characteristics. In order to produce the fine-grained nickel electrode active material, fine-grained nickel hydroxide is precipitated by adding a given amount of alkali to solution in which at least a nickel compound is dissolved while the solution is stirred. Each of the fine-grained nickel hydroxide has pores with 20 vol % or more of a combined volume of the pores being composed of pores of diameter 60 .ANG. or greater. Next, a given amount of alkali is gradually added to suspension including the fine-grained nickel hydroxide and dissolved cobalt compound so that cobalt hydroxide is precipitated on the external surface of the fine-grained nickel hydroxide. The fine-grained nickel electrode active material is produced in the above mentioned way. Each of the fine-grained nickel electrode active material comprises a nickel hydroxide and cobalt oxide having distorted crystal structure and oxidation number higher than +2. The nickel hydroxide has pores whose diameters are 60 .ANG. or greater. And the volume of such pores amounts to 20 vol % or more of the combined volume of all of the pores.

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Naruto, Japan

Akifumi Yamawaki