JPH0773870A - Manufacture of electrode plate for square battery - Google Patents

Abstract

PURPOSE:To efficiently manufacture an electrode plate for square battery in which short circuit in an assembly process caused by projection of a conductive substance is prevented to enhance reliability by covering the surface opposite the welding surface of a lead fixing part with an insulating material. CONSTITUTION:Part of a belt-shaped conductive substrate with three-dimensional net structure is densified to form a lead fixing part 1, and active material paste is impregnated in a region 2 except for the lead fixing part 1, of the conductive substrate to manufacture a belt-shaped electrode plate main body 3. Part of a belt-like metal thin plate 4 is welded to the lead fixing part 1. The surface opposite the welding surface of the lead fixing part 1 is at least covered with an insulating material 7, then punching work is applied thereto.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an electrode plate for a prismatic battery.

[0002]

2. Description of the Related Art Rectangular batteries represented by prismatic lithium batteries, prismatic nickel-cadmium batteries, and prismatic nickel-hydrogen batteries are used in portable electric devices and the like because they can have a high capacity and are excellent in space efficiency.

In the prismatic battery, an electrode group in which positive electrode plates and negative electrode plates are alternately laminated via separators is inserted into a rectangular metal case, and electrode plates of the same polarity are attached to the electrode plates. There is known a structure in which the lead tab is electrically connected to the same terminal directly or through a current collector.

In recent years, as the electrode plate for the prismatic battery, a large amount of electrode active material can be filled by using a highly porous conductive substrate having a three-dimensional network structure in order to further increase the capacity. The non-sintered electrode plate is used.

The above-mentioned prismatic battery electrode plate is manufactured, for example, by the following method. First, a part of a strip-shaped conductive substrate having a three-dimensional network structure is densified to form a lead mounting portion, and then a region other than the lead mounting portion of the conductive substrate is filled with an active material paste to form a strip-shaped conductive substrate. The electrode plate body is manufactured. Next, after a part of the strip-shaped metal thin plate is welded to the lead mounting portion, punching processing is performed to a predetermined size. As a result, a prismatic battery electrode plate having a structure in which the metal thin plate attached to the electrode plate body serves as a lead tab is manufactured.

In the prismatic battery electrode plate thus obtained, a part of the conductive substrate is projected in a whisker shape from the surface of the lead attachment portion opposite to the welding surface, so that the conductive substrate is directly assembled in the battery. The whiskers protrude through the separator and come into contact with the adjacent electrode plate of the other electrode, resulting in a short circuit. For this reason, it is necessary to cover the surface of the lead mounting portion opposite to the welding surface with an insulating substance such as an insulating tape.

However, in the case of manufacturing a large number of prismatic battery electrode plates, the work of surely covering the surface of each lead mounting portion opposite to the welding surface with the insulating substance without protruding the conductive substrate. Was complicated.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the prior art. Since the surface of the lead mounting portion opposite to the welding surface is coated with an insulating material, the conductive substrate is formed. It is intended to provide a method capable of efficiently manufacturing a highly reliable electrode plate for a prismatic battery, in which a short circuit at the time of assembling the battery due to the protrusion of the battery is prevented.

[0009]

According to the present invention, a part of a strip-shaped conductive substrate having a three-dimensional network structure is densified to form a lead mounting portion, and then the region of the conductive substrate excluding the lead mounting portion. A step of preparing a strip-shaped electrode plate body by filling the active material paste into the step, a step of welding a part of the strip-shaped metal thin plate to the lead attachment part, and a surface of the lead attachment part opposite to the welding surface. Is coated with at least an insulating material, and then a punching process is carried out.

The surface of the lead mounting portion opposite to the welded surface can be covered with an insulating material by applying a band-shaped insulating tape or applying an insulating resin coating.

[0011]

According to the method of the present invention, a part of a strip-shaped conductive substrate having a three-dimensional network structure is densified to form a lead mounting portion, and then the conductive substrate is activated in an area excluding the lead mounting portion. A strip-shaped electrode plate body is prepared by filling the material paste. Subsequently, a part of the strip-shaped thin metal plate is welded to the lead mounting portion. Subsequently, at least the surface of the lead mounting portion opposite to the welding surface is covered with an insulating material, and then punching is performed. As a result, a thin metal plate is attached as a lead tab to the lead attachment portion of the electrode plate body,
Also, since the surface of the lead attachment portion opposite to the welding surface is covered with an insulating material, a highly reliable prismatic battery electrode plate is prevented from being short-circuited when the battery is assembled due to the protrusion of the conductive substrate. Can be manufactured.

In addition, since the surface of the strip-shaped electrode plate body on the side opposite to the welding surface of the lead attachment portion is coated with an insulating material before the punching process, it is almost obtained by the punching process as in the conventional method. The complicated work of covering the surface of the lead mounting portion of the final product opposite to the welding surface with an insulating substance is not required. Therefore, the prismatic battery electrode plate can be manufactured with good mass productivity.

If the surface of the strip-shaped electrode plate body on the side opposite to the welding surface of the lead mounting portion is coated with an insulating material, and the surface of the strip-shaped metal thin plate opposite to the welding surface is coated with an insulating material. Since a short circuit at the time of assembling the battery due to a burr generated in the strip-shaped metal thin plate due to welding or the like can be prevented, a prismatic battery electrode plate having higher reliability can be manufactured.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings. Example 1 First, one end portion of a strip-shaped nickel substrate having a three-dimensional network structure is compressed and densified to form a lead mounting portion, and nickel hydroxide is applied to a region of the strip-shaped nickel substrate other than the lead mounting portion. The active material paste which is the main component is filled, and further dried and rolled. As a result, a strip-shaped electrode plate body 3 having the lead attachment portion 1 and the active material filling portion 2 as shown in FIG. 1 is produced.

Then, as shown in FIG. 2, the lead mounting portion 1 of the strip electrode plate body 3 and one end portion of the strip metal thin plate 4 made of a nickel-plated steel plate having a thickness of 0.1 mm are overlapped with each other to face each other. By passing it between the rollers 5 and 6 which also function as the welding poles, one end of the thin metal plate 4 is electrically resistance welded to the lead mounting portion 1.

Next, as shown in FIG. 3, the strip-shaped electrode plate body 3 is made of an insulative resin coated with an adhesive on the surface of the lead mounting portion 1 opposite to the welding surface of the lead mounting portion 1. A second length made of an insulating resin which is supplied with the first long insulating tape 7 and has an adhesive coated on the side of the strip-shaped metal sheet 4 on the surface opposite to the welding surface. By supplying the length insulation tape 8 and passing it between the pair of rollers 9 and 10 facing each other, the first long insulation is formed so as to cover the surface of the lead mounting portion 1 opposite to the welding surface. The tape 7 is attached and the second long insulating tape 8 is attached so as to cover the surface of the strip-shaped metal thin plate 4 opposite to the welding surface. Then, by punching and pressing these, 150 nickel electrode plates as shown in FIG. 4 described below were manufactured.

FIG. 4 (a) is a plan view showing the nickel electrode plate of Example 1, and FIG. 4 (b) is an enlarged sectional view of an essential part taken along line YY of FIG. 4 (a). That is, this nickel electrode plate includes an electrode plate body 13 having a lead mounting portion 11 and an active material filling portion 12, a mounting portion 14a welded along the lead mounting portion 11 of the electrode plate body 13 and the mounting portion 14a. A lead tab 14 made of a T-shaped nickel-plated steel plate having a current collecting portion 14b vertically drawn from the center of the lead tab, and attached so as to cover the surface of the lead mounting portion 11 opposite to the welding surface. It is composed of a first insulating tape 15 and a second insulating tape 16 attached so as to cover the surface of the lead tab 14 opposite to the welding surface. Comparative Example 1 150 nickel electrode plates were manufactured in the same manner as in Example 1 except that the first and second strip-shaped insulating tapes were not attached. Comparative Example 2 A first insulating tape cut to a predetermined size so as to cover a surface of a lead mounting portion of a main body of an electrode plate after punching and pressing, which surface is opposite to a welding surface, is attached, and a welding surface of a lead tab is attached. A second insulating tape cut into a predetermined size so as to cover the surface on the opposite side is attached. This allows
150 nickel electrode plates having the same structure as in Example 1 were manufactured.

Using the nickel electrode plates obtained in Example 1 and Comparative Examples 1 and 2, 50 prismatic nickel-hydrogen secondary batteries as shown in FIG. 5 described below were assembled. That is, the electrode group 22 is housed in the metal case 21 having a low-angle rectangular shape. The electrode group 22 includes three nickel electrode plates 24 and two U-shaped hydrogen storage alloy electrode plates 23 wrapped with a bag-shaped separator 23 impregnated with an alkaline electrolyte. A nickel electrode which is formed by inserting the wrapped nickel electrode plate 24 into the U-shaped hydrogen storage alloy electrode plate 23 to form an electrode plate unit, and is wrapped between the two electrode plate units by the bag-shaped separator 23. It has a structure in which a plate 24 is arranged. The hydrogen storage alloy electrode plate 23 is pressed against the inner surface of the metal case 21. A metallic sealing plate 26 having a hole 25 in the center thereof is airtightly caulked and fixed to the opening of the metal case 21 via an insulating gasket 27. On the lower surface of the sealing plate 26,
The lead dub 28 of each nickel electrode plate 24 is connected. An elastic body 29 is arranged on the upper surface of the sealing plate 26 so as to close the hole 25, and a hat-shaped positive electrode terminal plate 30 is welded so as to compress and cover the elastic body 29.

For each of the 50 batteries obtained in Example 1 and Comparative Examples 1 and 2, it was confirmed whether insulation failure occurred at a load of 500 mV. The results are shown in Table 1 below. As apparent from Table 1, in the battery of Example 1, the surface of the nickel electrode plate main body opposite to the welding surface of the lead attachment portion was covered with the insulating tape. Since short circuits due to protrusions are prevented, there is no insulation failure.

On the other hand, in the battery of Comparative Example 1, since the surface of the nickel electrode plate body opposite to the welding surface of the lead mounting portion is exposed, this is caused by the protrusion of the conductive substrate from the nickel electrode plate. Short circuit causes insulation failure.

The battery of Comparative Example 2 has no defective insulation like the battery of Example 1. However, in the manufacturing process of the nickel electrode plate, since it is difficult to accurately position and attach the first and second insulating tapes, it was caused by the positional displacement and peeling of the first and second insulating tapes. About 10% of defective products occurred.

In the production of the nickel electrode plate of the above-mentioned embodiment, the surface of the strip-shaped electrode plate body opposite to the welding surface of the lead mounting portion is covered with a long insulating tape and the welding surface of the strip-shaped metal thin plate is opposite. The side surface was also covered with the long insulating tape, but the same effect was obtained when only the surface opposite to the welding surface of the lead attachment portion of the strip electrode plate body was covered with the long insulating tape.

[0023]

As described above, according to the present invention, since the surface of the lead mounting portion opposite to the welding surface is coated with an insulating material, a short circuit due to the protrusion of the conductive substrate at the time of assembling the battery is prevented. It is possible to provide a method capable of efficiently manufacturing a prevented and highly reliable electrode plate for a prismatic battery.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a manufacturing process of a nickel electrode plate of Example 1.

FIG. 2 is an explanatory view showing a manufacturing process of the nickel electrode plate of Example 1.

FIG. 3 is an explanatory view showing a manufacturing process of the nickel electrode plate of Example 1.

FIG. 4 is an explanatory diagram showing a nickel electrode plate of Example 1.

FIG. 5 is a sectional view showing a prismatic nickel-hydrogen secondary battery.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Lead attachment part of strip | belt-shaped electrode plate main body, 2 ... Active material filling part of strip | belt-shaped electrode plate main body, 3 ... Strip-shaped electrode plate main body, 4 ... Strip-shaped metal thin plate, 5, 6, 9, 10 ... Roller, 7 ... 1st Long insulating tape, 8 ... second long insulating tape, 11 ... lead mounting portion of electrode plate body, 12 ... active material filling portion of electrode plate body, 1
3 ... Electrode plate body, 14 ... Lead tab, 14a ... Lead tab mounting portion, 14b ... Lead tab current collecting portion, 15 ... First
Insulating tape, 16 ... Second insulating tape.

Claims (1)

[Claims] 1. A part of a strip-shaped conductive substrate having a three-dimensional network structure is densified to form a lead attachment part, and an area excluding the lead attachment part of the conductive substrate is filled with an active material paste. A step of producing a strip-shaped electrode plate body by welding, a step of welding a part of the strip-shaped thin metal plate to the lead mounting portion, and at least a surface of the lead mounting portion opposite to the welding surface is coated with an insulating material. And a step of performing a punching process afterward.