JPH053029A - Hydrogen storage alloy electrode and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a low resistive and a high capacity density hydrogen storage alloy by combining hydrogen storage alloy powders and conductive fibers with metal plated phases. CONSTITUTION:A metal plating is applied to a mixture of conductive fibers 1 and electrode materials 2 mixed in advance so as to bind them with metal plated phases 3, thereby to hold the electrode materials 2 in a three dimensional porous body made up with conductive fibers l. Whereby, the electrode materials 2 can be made to have high density and low resistance so that a hydrogen storage alloy electrode, having high capacity density and low internal resistance, can be provided. Here, the conductive fibers 1 is preferably selected from the group consisting of a nickel fiber, a copper fiber, and a carbon fiber; and the metal plating is preferably a nickel plating or a copper plating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrogen storage alloy electrode and a method for producing the same, and more particularly to high density electrode material.

[0002]

2. Description of the Related Art Conventional electrodes and electrodes are manufactured by applying a paste containing an electrode material to an electrode substrate such as a wire mesh, a casting grid, punching metal, or expanded metal, and a three-dimensional material such as b foam metal or metal felt. There are a method of filling a porous body with a paste or a slurry containing an electrode material, and a method of chemically or electrochemically impregnating a porous sintered body of c metal with an electrode material.

[0003]

However, the above-mentioned a
Has a problem in that the electrode material can be present at a high density, but the electric resistance of the paste portion is high and the retention of the electrode material is poor. Also, the above b is
It is difficult to uniformly fill the inside of the three-dimensional porous body with the electrode material, and it is difficult to increase the density of the electrode material. It must be repeated many times, and it is industrially difficult to increase the density of the electrode material.

[0004]

In order to solve the above problems, in the present invention, a mixture of a conductive fiber and an electrode material is preliminarily mixed and metal-plated to bond the conductive fiber and the electrode material. It is intended to hold the electrode material in the three-dimensional porous body.

[0005]

Function: The electrode material can be made to exist with high density and low resistance.

[0006]

EXAMPLES Examples of the present invention will be described. FIG. 1 is a schematic view of a main part of a hydrogen storage alloy electrode according to the present invention. Reference numeral 1 is a conductive fiber, which are entangled with each other, and the electrode material 2 is included in the gap. The conductive fiber 1 and the electrode material 2 are bonded by a metal plating phase 3.

In the present invention, first, a hydrogen storage alloy (LaNi _4.7 Al _0.3 ) was used as the electrode material 2 and pulverized to 100 mesh or less. This was mixed with nickel fiber having a length of 25 mm at a weight ratio of 95: 5, and the PTFE dispersion was added to this so that the addition amount was 5%, and the mixture was kneaded to form a paste. Molded. This was baked at 350 ° C. in an argon atmosphere to obtain a porous sheet. To this, 1.2 wt% of nickel was added by electroless plating. This was rolled to obtain a hydrogen storage alloy electrode having a thickness of 0.5 mm. Next, for comparison, a foamed nickel was filled with a paste prepared by adding PVA (2 wt%) to a hydrogen storage alloy powder, and a hydrogen storage alloy electrode was rolled to a thickness of 0.5 mm to produce a hydrogen storage alloy electrode.

(Comparative Example 1) Further, P was added to the hydrogen storage alloy powder.
A paste containing TFE (2 wt%) was applied to a nickel wire mesh and rolled to a thickness of 0.5 mm to prepare a hydrogen storage alloy electrode.

(Comparative Example 2) These hydrogen storage alloy electrodes were repeatedly charged and discharged in an aqueous 31 wt% potassium hydroxide solution at a current density of 30 mA / g with respect to the weight of the hydrogen storage alloy powder to obtain a capacity density at maximum capacity. Were compared. Further, by combining these hydrogen storage alloy electrodes and a nickel electrode used in a nickel-cadmium battery, an AA type sealed battery having a capacity of 700 mAh was produced and the internal resistance was measured. The results are shown in Table 1.

[0010]

[Table 1]

As is clear from the above results, the capacity density is in the order of Example> Comparative Example 2> Comparative Example 1, and the internal resistance is in the order of Example <Comparative Example 1 <Comparative Example 2. Recognize.

[0012]

Industrial Applicability As described above, according to the present invention, a hydrogen storage alloy electrode having a high capacity density and a low internal resistance can be obtained, which is of great industrial value.

[Brief description of drawings]

FIG. 1 is a schematic view showing a main part of a hydrogen storage alloy electrode according to the present invention.

[Explanation of symbols]

1 is a conductive fiber, 2 is an electrode material, 3 is a metal plating phase.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takeshi Tsuda             2-1-1, Nishishinjuku, Shinjuku-ku, Tokyo             To Denki Co., Ltd.

Claims (6)

[Claims] 1. A porous hydrogen storage alloy electrode comprising a hydrogen storage alloy powder and conductive fibers bonded by a metal plating phase. 2. A hydrogen storage alloy powder, a binder, and conductive fibers are kneaded to form a paste, which is formed into a sheet and then fired to form a porous body, which is metal-plated and then given a predetermined thickness. A method for producing a hydrogen storage alloy electrode, which comprises pressing up to this point. 3. The hydrogen storage alloy electrode according to claim 1, wherein the conductive fiber is any one of nickel fiber, copper fiber and carbon fiber. 4. The method for producing a hydrogen storage alloy electrode according to claim 2, wherein the conductive fiber is any one of nickel fiber, copper fiber and carbon fiber. 5. The hydrogen storage alloy electrode according to claim 1, wherein the metal plating is nickel plating or copper plating. 6. The method for producing a hydrogen storage alloy electrode according to claim 2, wherein the metal plating is nickel plating or copper plating.