JPH10223218A - Manufacture of sheet-like electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet-like electrode in which an active material layer is locally removed with good accuracy and the active material layer, including the part in the vicinity of a removed part is firmly jointed with a metallic substrate by removing the active material layer at the prescribed position along a holding member by a peeling tool having an acute edge. SOLUTION: A part at a position in contact with a part 4 from which an active material layer is removed is held by a holding member 8, and an active material layer 2 is peeled by a peeling tool 7 to locally remove the active material layer. The edge of the peeling tool 7 is preferably 3-60 deg. in tool angle. The gap between the holding member 8 and the peeling tool 7 eliminates the distance between the active material layer 2 to be pressed by the edge of the holding member 8 and the active material layer 2 to be peeled by the edge of the peeling tool 7, so that the active material layer 2 formed on a metallic substrate 1 can be removed locally in a condition having smooth seared section.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a sheet-like electrode such as a sheet-like positive electrode and a sheet-like negative electrode, and more particularly, to a method in which a sheet-like positive electrode and a sheet-like negative electrode are spirally wound via a separator. The present invention also relates to a method for producing a sheet-like electrode, which comprises partially removing an active material layer of a sheet-like electrode used in a battery in which the obtained spiral electrode body is inserted into a cylindrical battery case.

[0002]

2. Description of the Related Art A sheet-like electrode used in a nickel-hydrogen storage alloy battery or the like is composed of a metal substrate as a core material and an active material layer formed on one or both surfaces thereof. After the formation of the active material layer, pressure is applied with a roll or the like in order to firmly adhere to each other to increase the bonding strength between the metal substrate and the active material layer.

[0003] Incidentally, in a battery such as a nickel-hydrogen storage alloy battery in which a sheet-like positive electrode and a sheet-like negative electrode are spirally wound via a separator, and the obtained spiral electrode is inserted into a cylindrical battery case. In order to increase the capacity, it is necessary to remove the active material layer on the outer surface of the outermost layer and the active material layer on the innermost layer which do not contribute to the reaction.

Therefore, conventionally, as shown in FIG. 4, an ultrasonic vibrator 9 partially applies ultrasonic vibration to the active material layer 2 to partially remove the active material layer, or After locally applying water or a solvent to the layer, the active material layer has been partially removed by scraping with a scraper or the like.

[0005] However, when the active material layer is partially removed after the bonding force of the active material layer is weakened by applying ultrasonic vibration or applying water or a solvent as described above, when the active material layer is to be partially removed, Since the bonding strength of the surrounding active material layers is weakened, there is a problem that the active material layer near the removed portion is separated from the metal substrate after winding.

In addition, when ultrasonic vibration is applied to the active material layer to remove the active material layer, a large amount of dust of the active material is generated, so that a step for removing the dust is required. However, there is also a problem that a new facility for collecting the removed active material is required.

Further, when a porous metal plate such as a punching metal is used as a metal substrate, the active material layer on one surface is connected to the active material layer on the other surface via a hole, so that an ultrasonic wave is used. If the active material layer is removed by applying vibration or applying water or a solvent to reduce the bonding force of the active material layer to the metal substrate, the ultrasonic wave or applying water or a solvent may be used to remove the active material layer. Since the active material layer becomes flexible,
There was a problem that the active material layer on the opposite side peeled off.

[0008]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the prior art, removes the active material layer with high accuracy, and removes the active material layer including the vicinity of the removed portion. An object of the present invention is to provide a sheet-like electrode firmly bonded to a substrate.

[0009]

SUMMARY OF THE INVENTION According to the present invention, there is provided a pressing member for holding a position of a metal substrate serving as a core material in contact with a predetermined removed portion on both sides of a metal substrate so that the active material layer does not collapse. This problem has been solved by removing the active material layer at a predetermined position along the holding member with a peeling tool having a sharp edge.

That is, as described above, the active material layer at the portion that is not removed is pressed and protected by the pressing member, so that peeling of the active material layer at the extra portion is prevented, and the boundary between the removed portion and the non-removed portion is prevented. The active material layer is partially removed so that the surface is as accurate as predetermined, and a sheet-like electrode in which the active material layer is firmly joined to the metal substrate can be obtained even near the removed portion.

[0011]

FIG. 1 shows an example of a manufacturing method according to the present invention. FIG. 2 is a front sectional view of a main part thereof (a plane viewed from A in FIG. 1), and FIG. 2 is a cross-sectional view of a side surface (however, a surface viewed from B in FIG. 1). As the metal substrate 1, a cold-rolled steel punching metal or the like having a thickness of 0.05 to 0.1 mm is used, and an active material-containing paste containing an active material, a binder, and water is applied to both surfaces thereof, and dried. By forming the active material layer 2, the thickness of the active material layer 2 is reduced to 0.1.
A sheet-like electrode 3 of 2 to 0.5 mm is manufactured. When the electrode 3 is a negative electrode, a hydrogen storage alloy is usually used as an active material, and when the electrode 3 is a positive electrode, nickel hydroxide is usually used as an active material.

Then, a position in contact with the portion 4 from which the active material layer is to be removed is pressed by the pressing member 8 to a contact pressure of 0.1 to 1 kg /.
cm ² , and the active material layer in the meantime is peeled off with a tool 7
By peeling, the active material layer is partially removed. Reference numeral 5 denotes a removed piece of the active material layer, and reference numeral 6 denotes a removed portion of the active material layer.

The edge 7a of the peeling tool 7 preferably has an edge angle of 3 to 60 ° as shown in FIG. 3, and moves forward while pressing the sheet-like electrode with a force of 0.5 to 10 kg per 1 cm of the removal width. Then, the active material layer is separated.

The gap between the holding member 8 and the peeling tool 7 is
As shown in FIG. 2, the distance between the active material layer 2 kept at 0.02 to 0.1 mm and compressed at the edge 8 a of the holding member 8 and the active material layer peeled off at the edge 7 a of the peeling tool 7 is maintained. By eliminating the distance, the active material layer 2 formed on the metal substrate 1 can be partially removed to have a smooth shear surface.

The material of the peeling tool 7 is usually a metal, but is not limited to a metal, and may be a ceramic or the like. The material of the pressing member 8 is usually a metal, but is not limited to the metal. For example, resin or rubber may be used as long as the material has strength.

In the case where the width of the portion to be removed is wide, the active material layer may be removed by dividing it into a necessary number of times.
In addition, the removal direction is not limited to the case where the sheet electrode is removed in one direction from one end to the other end as shown in FIG. 1, and the removal is performed from the center of the sheet electrode toward one end surface, Thereafter, the direction may be reversed and removed from the center toward the other end face, and the removal may be performed in two steps.

The sheet-like electrode from which the active material layer is to be partially removed may be either a sheet-like positive electrode, a sheet-like negative electrode, or both.

[0018]

Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

Example 1 A binder solution 28 in which polyvinylidene fluoride was dissolved in N-methyl-pyrrolidone at a concentration of 12% with respect to 100 parts by weight of a hydrogen storage alloy powder mainly composed of MmNi _5.
Add the parts by weight, mix and stir well to prepare a uniform paste, and apply this paste to a metal substrate having a thickness of 66 μm.
m on both sides of a punching metal, dry and dry to a total thickness of 4
A sheet-like electrode having a thickness of 66 μm and a thickness of the active material layer on one side of 200 μm was prepared.

As a peeling tool, a tool made of high-speed steel and having a cutting edge angle of 20 ° and a width of 26 mm was used, and as a holding member, a rectangular tool made of alloy tool steel was used.

As shown in FIG. 1, pressing members 8 are arranged on the active material layer 2 of the sheet electrode 3 on both sides of the portion 4 from which the active material layer is to be removed. From the right to the left to remove the active material layer with a width of 26 mm.

In removing the active material layer, the gap between the pressing member 8 and the peeling tool 7 is set to 0.05 mm, and the active material layer is pressed by the pressing member 8 at a surface pressure of 0.5 kg / cm ^2. The tool 7 was advanced while being pressed with a force of 1.2 kg per 1 cm of the removal width.

COMPARATIVE EXAMPLE 1 As shown in FIG. 4, the same sheet-like electrode as in Example 1 was applied to the active material layer 2 with an ultrasonic vibrator 9 at a frequency of 20 kHz, an amplitude of 35 μm and a surface pressure of 2 kg / cm ² over a width of 20 mm. Ultrasonic vibration was applied under the conditions described above to partially remove the active material layer.

The partial removal of the active material layer is performed in the same manner as in Example 1,
Comparative Example 1 was also performed on each of the 600 samples, and a defective product was defined as a defective product in which the active material layer was partially removed and the boundary of the active material layer removed portion had a gap of 0.5 mm or more. The defect occurrence rate was examined.

The results are shown in Table 1. However, in Table 1, the total number of samples subjected to the test is described in the denominator so that the relationship between the total number of samples subjected to the test and the number of failures can be clearly understood. The failure occurrence rate was indicated by the method described in (1).

[0026]

[Table 1]

As shown in Table 1, in the sheet-like electrode from which the active material layer was partially removed in Example 1, no failure was observed.

On the other hand, in Comparative Example 1 in which the active material layer was removed by applying ultrasonic vibration according to the conventional method,
Defectives occurred in 45 of the samples. In the case of Comparative Example 1, a large amount of active material dust was generated because the active material layer was removed by the application of ultrasonic vibration.
Then, there was no generation of such a large amount of dust of the active material.

Further, in the case of Comparative Example 1, since the active material layer was removed by the application of ultrasonic vibration, the active material on the surface opposite to the removed surface was partially removed. In the case of No. 1, there was no such removal of the active material on the opposite side.

In the above embodiment, a sheet negative electrode using a hydrogen storage alloy as an active material has been described as an example of a sheet electrode, but the same effect can be obtained with a sheet positive electrode.

[0031]

As described above, according to the present invention, the active material layer of the sheet-like electrode is pressed with the pressing member, and the active material layer is removed along the pressing member with a peeling tool, thereby achieving accurate activation. A sheet-like electrode from which the material layer was partially removed could be manufactured.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a manufacturing method of the present invention.

FIG. 2 is a front sectional view of a main part of FIG. 1;

FIG. 3 is a side sectional view of a main part of FIG. 1;

FIG. 4 is a perspective view showing a conventional method.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 metal substrate 2 active material layer 3 sheet electrode 4 part from which active material layer is to be removed 5 active material layer removal piece 6 active material layer removal part 7 stripping tool 7 a edge of stripping tool 8 pressing member 8 a pressing Member edge

Claims (3)

[Claims] 1. A sheet-shaped positive electrode and a sheet-shaped negative electrode each having an active material layer formed on both surfaces of a metal substrate are spirally wound via a separator, and the obtained spiral electrode body is inserted into a cylindrical battery case. In a method for manufacturing a sheet-like electrode for partially removing an active material layer of at least one of a sheet-like positive electrode and a sheet-like negative electrode used in a battery to be used at a predetermined position, the active material surrounding the predetermined position is removed. A method for manufacturing a sheet-like electrode, comprising: pressing a material layer with a pressing member; and removing an active material layer at a predetermined position along the pressing member with a peeling tool having an acute edge. 2. As a tool for removing the active material layer, 3 to 6
2. The method for manufacturing a sheet-like electrode according to claim 1, wherein a peeling tool having an edge having an edge angle of 0 [deg.] Is used. 3. The active material layer is removed by moving the peeling tool from the center of the sheet-shaped electrode toward one end face and the other end face at least two times. Item 2. The method for producing a sheet-like electrode according to Item 1.