JPS61185865A - Method for manufacturing electrode for alkaline storage battery - Google Patents

Abstract

PURPOSE:To improve conductivity of an electrode and utilization ratio of active matter, cyclic characteristic and high rate electric discharge performance by rolling a porous substrate in which powder condition active matter is charged to be predetermined thickness. CONSTITUTION:In manufacturing process of an electrode, water, binder and organic hollow bulb 1 applied by metal plating on its surface are mixed to produce slurry and it is applied on a metal sheet 2 and dried, and sintered in reduction atmosphere so that the metal on the organic hollow bulb surface becomes half melted to obtain porous substrate 3 as active matter retaining body, and powder type material 4 is directly filled in the substrate and the substrate is rolled to be a predetermined thickness. Then, an electrode can be manufactured without complicated chemical impregnation as in sintered type electrode, and as conductive core and conductive matrix are provided in the electrode, conductivity is improved and current distribution in the electrode is equalized, and excellent active matter utilizing ratio, high rate electric discharge characteristic and cyclic characteristic can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a method for manufacturing an electrode for an alkaline storage battery, which comprises filling an active material holder with a powdered active material.

(b) Prior Art Two types of electrodes are generally used for alkaline storage batteries: sintered electrodes and paste electrodes. A sintered electrode is, for example, a slaty IJ-based electrode whose main component is difluoride powder.
t-A porous substrate is obtained by coating the surface of a metal sheet with a large number of punched holes and sintering it. The active material is activated by a chemical impregnation operation in which the pores of the active material support are impregnated with a metal salt solution such as a difluoride salt solution or a cadmium salt solution, and then the metal salt is completely replaced with an alkali. Manufactured by filling a substance holder.

This sintered electrode is mainly used as a nickel anode.

Is this manufacturing method a complicated process such as impregnating the active material support with a metal salt solution and replacing it with chilukali? I need it.
In order to impregnate a predetermined amount of active material, the above-mentioned operation must be repeated several times, which has drawbacks such as high cost and long manufacturing time. On the other hand, in a paste type electrode, the active material powder is directly mixed with a binder, water, etc. to form a paste. Since it can be manufactured by simply drying it after being deposited on the metal sheet, the manufacturing process can be simplified and productivity is excellent. However, unlike the sintered electrode, it does not have a conductive matrix made of sintered metal in the t-electrode, so it has the disadvantage of poor conductivity and low utilization of the active material, and also suffers from significant cycle deterioration.

In recent years, a porous substrate having three-dimensionally continuous pores such as a foamed metal is used as an active material holder, and the active material powder is either directly placed in the active material holder or mixed with a binder and water to form a paste. Fill it up! The pole is JP-A-58-1
Publication No. 02463 and Japanese Patent Publication No. 56-37664 (
It is proposed in This electrode is easy to prepare and can be filled into an active material holder in the form of active substance*1 powder.
! The advantage is that the active material holder has high porosity and does not require the entire core, so the amount of tX filled with the active material can be increased and the energy density can be increased. have. but.

On the other hand, this one! Is the pole the core? # from not having it! ! There are disadvantages such as the strength of the electric tab attachment part is weak, the current collection is insufficient, and the flow distribution is unevenly distributed near the current collecting tab, making it possible to charge and discharge only locally. It's also inferior.

→ While the invention is trying to solve the problem, the present invention relates to an electrode prepared by filling an active material holder with active material 7 in powder form! Completely improves electrode conductivity, improves active material utilization, cycle characteristics, and high rate discharge performance (kH)
It is something that we try to do.

(2) Elaborate means to solve all the problems The method for manufacturing electrodes for alkaline storage batteries of the present invention is as shown in the schematic diagram showing the manufacturing process of electrodes. Slurry made by mixing organic surface hollow spheres + llk? , Metal Sea H2
After applying 1vc and drying, ■ complete sintering in a reducing atmosphere to such an extent that the metal on the surface of the organic hollow sphere is in a semi-molten state to obtain a porous G substrate 13+k as an active material holder, ◎
After the powdered active material IJf is directly filled into the substrate, it is rolled to a predetermined thickness.

(e) Operation: A hollow sphere made of organic material whose surface is plated with metal is placed in a reducing atmosphere for 55 minutes to the extent that the gold plated metal is in a semi-molten state.
When sintered at 00 to 900'c, the internal organic hollow spheres decompose, break the metal plating, and are discharged to the outside and removed. Further, at this time, since the metal plating is in a semi-molten state, adjacent metal platings are bonded to each other and bonded to the metal sheet, forming a porous substrate having pores with a relatively large diameter. The substrate thus prepared can be directly filled with the active material in its entire powder state without performing any complicated chemical impregnation operations. Furthermore, by filling the substrate with powdered active material *r and then rolling it, all excess space in the substrate can be removed and the active material can be firmly held within the substrate.

Therefore, the method for recycling electrodes for alkaline storage batteries using the above means is much simpler than the method for manufacturing sintered electrodes. Is it a conductive IJ ux made by combining the core body and metal plating in a semi-molten state? Therefore, the conductivity inside the electrode is improved, and the presence of the core improves the mechanical strength of the electrode. Furthermore, the metal plating on the surface of the organic hollow sphere has a thickness of 5 to 50 μm.
Preferably, a substrate having pores with a diameter such that the active material can be completely filled smoothly into the sphere diameter of the organic surface hollow sphere. 5 to get
It is desired that the thickness is 0 to 200μ. As a binder for holding and fixing the active material in the substrate, an alkali-resistant binder is effective, such as polytetrafluoroethylene or polyvinyl alcohol.

(f) Example Low-boiling point regenerated hydrogen All inside: The surface of an organic hollow sphere with a diameter of 10 to 100 μm (trade name Microsphere-1 Matsumoto Yushiki) was coated with nickel plating with a thickness of 15 μm. 20 parts by weight of hollow spheres, 3 parts by weight of methylcellulose and 100 parts by weight of water. Mix and prepare sura IJ-7.

Next, a steel plate with a length of 10crIL and 111M was constructed with a large number of bunch holes and a nickel-plated surface.
401! , the above slurry is applied to both sides of a metal sheet with a thickness of 0.09mm. Coat and dry. At this time, the sum of the thicknesses of the layers obtained by coating and drying the slurry on the metal sheet and both sides thereof was 5M. Thereafter, this was sintered at 600'C for 2 minutes in a reducing atmosphere to decompose and remove organic matter, resulting in a porous substrate 7 with a spatial volume of 9396!
-I got it.

The porous substrate prepared in this way was treated with dihydroxide as an active material.
100F, water 200 da, and polyvinyl k 7
k: +-ru 1opt- viscosity 1000c mixed
The process of immersing the active material in the ps slurry for 2 minutes, drying it at 9°C for 20 minutes, filling it, and completely drying the fC slurry was repeated 40 times to fill the active material into the substrate, and then rolling it to a thickness of 1 g. A friend of the electrode of the present invention.

Also, for comparison, BASTO is made by kneading nickel hydroxide powder 10F and hydroxyl 10-vinyl cellulose. ! - Apply the gold to both sides of the gold sheet and dry it to use as a reference electrode.

The results of each injection ability test for these electrodes are shown in the table below.

As is clear from the table, the electrode of the present invention has a significantly improved active material utilization rate compared to the comparative electrode, and is excellent in cycle deterioration and high rate discharge characteristics.

(g) Effects of the invention A method for manufacturing an electrode for an alkaline storage battery according to the present invention.

A slurry made by mixing water, banhgu, and organic hollow sphere gold with metal plating on the surface? 1. A porous substrate that is coated on a metal sheet, dried, and then sintered in a reducing atmosphere? Since the substrate is fully filled with powdered active material and then rolled to a predetermined thickness, the electrode can be manufactured without the need for complicated chemical impregnation operations unlike sintered electrodes. It is easy to manufacture, and the electrode made in this way has a conductive core and a conductive matrix inside, which improves the conductivity within the electrode and allows current to pass through the core. This makes the current pores flowing through the conductive matrix and the narrow electrode uniform, resulting in excellent active material utilization, no-ylate release characteristics, and cycle characteristics. Furthermore, since the electrode does not contain a core, it has the advantage that the mechanical strength of the electrode is high.

[Brief explanation of drawings]

The drawings are schematic diagrams showing the electrode manufacturing process in the method for manufacturing electrodes for alkaline storage batteries of the present invention. +21... Gold h1 sheet, ll+... Organic hollow sphere with metal plating on the surface, (31... Porous substrate, (41... Powdered active material).

Claims (1)

[Claims] (1) A slurry made by mixing water, a binder, and organic hollow spheres with metal plating on the surface is applied to a metal sheet, dried, and then sintered in a reducing atmosphere to obtain a porous substrate. A method for manufacturing an electrode for an alkaline storage battery, comprising filling the substrate with an active material in powder form and then rolling the substrate to a predetermined thickness.