JPH09283131A - Manufacture of battery electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery electrode in which removing of an active material in a lead piece welding part is unnecessary in the manufacturing process of the battery electrode formed by filling a pasty active material in a belt- shaped metal porous body having three-dimensional continuous spaces. SOLUTION: A belt-shaped metal porous body 1 is made to run in the lengthyl direction, a pastyactive material is discharged from a nozzle 2 having the length shorter than the width of the porous body, which is arranged closely to the one side of the metal porous body 1, to fill the active material in the spaces of the metal porous body 1, and at least one side edge along the lengthy direction of the metal porous body 1 is left as a metal part 4 where the active material is not filled.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing a battery electrode.

[0002]

2. Description of the Related Art A battery electrode is roughly classified into a paste type electrode in which a metal grid or net or the like is used as an active material support and a paste-like active material is filled in the electrode, and a micro electrode of a sintered metal substrate. There are a sintered electrode filled with a substance and a pocket electrode filled with a powdered active material in a tube or pocket having microporosity.

The paste type electrode has a great advantage that the electrode can be manufactured at a relatively low cost and relatively easily. However, in the case of the electrode of this method, there is a problem in durability especially in repeated use of charging / discharging of the secondary battery, and repeated charging / discharging causes the active material to fall off the support or swell the electrode. Performance deteriorates.

Sintered electrodes are superior to the other two in electrode properties and mechanical strength. However, the sintered substrate is expensive in material, and it may be necessary to repeat dipping into the active material solution and thermal decomposition several times to fill the micropores of the substrate with the required amount of active material. Since it is necessary to immerse the substrate in the active material solution for electrolytic deposition, and a complicated process is required as compared with other methods, the cost of the electrode is the highest.

Therefore, an electrode in which a foamed metal having a three-dimensionally continuous space is used as a base and a paste-like active material is filled in the base has become popular. Foamed metal has a porosity of 95%
It is extremely high, its pore size is large, and its strength is relatively large. Further, the pore size can be arbitrarily selected in the production. Therefore, it is possible to directly fill the paste-like active material or active material powder by appropriately selecting the pore size, and it is possible to manufacture the electrode in a much simpler process than the sintered electrode. There is.

On the other hand, in order to improve the large current and high rate discharge characteristics of the battery for use, at least one side of the electrode exposes a core material containing no active material, and a separator and a counter electrode are used to form an electrode plate. After winding the group in a spiral shape, a disc-shaped lead piece is welded to the core material portion containing no active material above the electrode plate group.
The so-called tabless method is adopted.

In this case, it has already been proposed to reinforce the welded portion by providing a metal sprayed layer on the edge of the electrode for welding the lead piece, or by pre-depositing a metal foil (Japanese Patent Publication No. 56-56). -86459).

[0008]

Although the lead pieces can be welded by the tabless method by the above method, it is necessary to remove the active material by brushing or the like at the electrode edges.
Loss of active material occurs. Moreover, the active material that cannot be removed is likely to remain on the edge of the electrode, which causes a decrease in the welding strength of the lead piece and a welding failure.

[0009]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides an electrode for electrical use which uses a porous metal body having a three-dimensionally continuous space as an active material support in the space. Is filled with an active material, and at least one edge along the length direction of the metal porous body is provided with a metal portion not filled with the active material, and that portion is used as a lead-welded portion of an electrode. It provides a manufacturing method.

As a method for producing the same, while a strip-shaped metal porous body having a three-dimensionally continuous space is run in the length direction, a nozzle is brought close to one surface of the metal porous body and the paste-like active material is discharged from the nozzle. By discharging, the paste-like active material is filled inside the space of the metal porous body corresponding to the width direction of the nozzle, and at least one side edge along the length direction of the metal porous body faces the nozzle. Without making the paste-like active material filled.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION According to the invention described in the claims, at the same time as filling the porous metal body with the paste-like active material, at least one side edge along the length direction of the porous body is for lead piece welding. In this case, the metal portion not filled with the active material is secured.

That is, in the present invention, as shown in FIG. 1, a nozzle which is made to approach one side of a porous metal body 1 having a three-dimensional space while running in the longitudinal direction thereof. When the space inside the metal porous body is filled by discharging the paste-like active material from the nozzle 2,
By making the length smaller than the width of the porous body 1, the metal portion 4 not filled with the active material is provided at the edge of at least one side (both left and right sides in this figure) of the porous metal body. When the paste-like active material is filled in the porous metal body, as proposed in Japanese Patent Application No. 7-261267, the paste-like active material is discharged at a constant pressure by bringing a nozzle close to one surface of the porous metal body. It was clarified that the paste is less likely to hit the surface of the porous metal body and is repelled, and the filling variation of the active material is significantly reduced.

The inventors of the present invention use the phenomenon that the rebound of the paste is reduced to make the length of the nozzle smaller than the width of the porous metal body so that the active material is filled in at least one edge of the electrode plate. It has been found that it is possible to leave the metal part 4 which is not. By using the metal portion 4 as the lead welded portion, it is not necessary to remove the active material, sufficient welding strength for welding the lead can be secured, and defective welding is reduced. Therefore, the productivity of the electrodes can be improved and the manufacturing cost of the battery can be reduced.

[0014]

An embodiment of the present invention will be described below.

With respect to 100 parts by weight of nickel hydroxide, 10 parts by weight of nickel metal powder and 5 parts by weight of cobalt oxide powder were added and powder-mixed so that the ratio of water to the total paste was 25% by weight. And kneaded to obtain a paste-like active material.

As shown in FIG. 1, a strip-shaped metal porous body 1 having a width of 120 mm, a thickness of 2.5 mm, a porosity of 98% and an average pore diameter of 200 μm is provided on one side with nozzles 2 having a length of 114 mm at both ends of the porous body. It was arranged so that the plain portions 4 of 3 mm each were formed. Then, the paste-like active material was filled into the space of the porous metal body while the porous metal body itself was running in the length direction. At this time, the nozzle 2 and the porous metal body 1
The distance between and was maintained at 0.1 mm, the running speed of the porous metal body was set at 7 m / min, and a fixed amount of 10 g / sec of the paste-like active material was discharged from the nozzle 2 to perform filling. Then, the porous metal body filled with the paste-like active material was pressed to 2.5 mm to 1.0 mm and cut in the width direction from the center to 60 mm to form the electrode a according to the present invention. This electrode a
Has a metal part 4 with a width of 3 mm which is not filled with active material.

For comparison, after the paste-like active material is sprayed and filled on the entire metal porous body, the active material filled on one edge along the length direction of the electrode plate is brushed to 3
The electrode b was removed with a width of mm. The electrodes a and b are used as the positive electrode 5, and the known hydrophilic non-woven fabric separator 6 and the known misch metal / nickel-based hydrogen storage alloy negative electrode 7 are used to spirally wind the electrode plate group, as shown in FIG. After the disc-shaped lead side 8 is welded to the tip of the electrode which is not filled with the active material by the tabless method, it is inserted into the case 9 and the long A
10000 group batteries of nickel-hydrogen storage battery (nominal capacity 3300 mAh) of size (outer diameter 16.5 mm, total height 66.0 mm) were formed. When the production of the electrodes a and b and the welding state of the disc-shaped lead portion 9 are compared,
The results are shown in (Table 1).

[0018]

[Table 1]

As is clear from this (Table 1), in the production of the electrode b of the comparative example, the welding strength is low because the active material remains on the edges. On the other hand, in the production of the electrode a in the present invention, the active material did not enter the edge of the electrode plate which did not face the nozzle, and the welding strength was excellent.

Further, the occurrence rate of welding defects is very low as compared with the comparative example. According to the present invention, it is possible to secure a metal portion that is not filled with an active material on at least one edge along the length direction of the electrode plate, and it is not necessary to remove the active material even during lead piece welding. Moreover, since the lead is welded to the metal portion which is not filled with the active material, the welding strength is improved,
In addition, welding defects are also reduced. Therefore, the productivity of the electrodes can be improved and the manufacturing cost of the battery can be reduced.

[0021]

As described above, according to the present invention, it is possible to manufacture an electrode in which at least one side edge along the length direction of the electrode is provided with a metal portion which is not filled with an active material. Further, by welding the lead piece to the metal portion which is not filled with the active material, sufficient welding strength can be secured and welding defects can be reduced, so that tabless current collection is performed. The electrodes can be manufactured more easily and efficiently than ever before.

[Brief description of drawings]

FIG. 1 is a diagram showing a manufacturing state of an electrode according to the present invention.

FIG. 2 is a schematic diagram of a nickel-hydrogen storage battery using an electrode according to the present invention.

[Explanation of symbols]

 1 Band-shaped metal porous body having a three-dimensionally continuous space 2 Nozzle 3 Metal part filled with active material 4 Metal part not filled with active material (plain area) 5 Positive electrode 6 Separator 7 Negative electrode 8 Disc-shaped Lead piece 9 case

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sadaaki Yokoo 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Within

Claims (1)

[Claims] 1. A nozzle having a length shorter than the width of the porous body which is made to approach one side of the porous metal while moving a strip-shaped porous metal having three-dimensionally continuous spaces in the longitudinal direction. While discharging the paste-like kneaded material mainly containing the active material to fill the space inside the porous body, at least one edge along the length direction of the metal porous body has a metal portion not filled with the active material. A method for manufacturing a battery electrode, comprising: