JPH09320567A - Device for welding tab to battery plate and manufacture of battery plate using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for welding tabs to battery electrodes, by which the tabs can be cut in such a manner that the tabs welded to plates do not undergo work hardening, and provide a method for manufacturing battery plates using the same. SOLUTION: This tab welding device is for welding a current collecting tab 2 to the coining part 3 of a battery plate 1 and comprises a positioning means 4 for the battery plate 1, a welding means 5 consisting of upper and lower electrodes 5b, 5a, a cutting means 6 consisting of a movable cutting blade 6a and a fixed cutting blade 6b that are vertically opposite to each other, and a sheet supply means 7 for placing the end 2b of a tab long-size sheet 2a on the surface 3b of the coining part 3, the above members being arranged in series in that order. The movable cutting blade 6a is located on the surface 3b of the coining part 3 on which the end 2b of the tab long-size sheet 2a is placed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tab welding device for a battery electrode plate and a method for manufacturing a battery electrode plate using the device, and more specifically, bending of the tab in a cutting step after completion of tab welding, Since the bending is small and the work hardening of the tabs is small, it is possible to easily focus the tabs of each electrode plate by incorporating multiple obtained electrode plates, and it is possible to easily cause a short circuit accident. TECHNICAL FIELD The present invention relates to a tab welding device for a battery electrode plate that enables manufacturing of a battery that is less likely to occur, and a method for manufacturing a battery electrode plate using the device.

[0002]

2. Description of the Related Art For example, a prismatic nickel-hydrogen secondary battery is
In an outer can having a predetermined size and shape, a positive electrode plate and a negative electrode plate are laminated with a separator interposed between them, and an electrode group is filled together with an alkaline electrolyte having a predetermined concentration, and the opening of the outer can is also used as a positive electrode terminal. It has a structure that is sealed with a double-sided lid.

The positive electrode plate used at this time usually has a structure in which a tab 2 is attached to an electrode plate 1 as shown in FIG. Here, the electrode plate 1 has a porous collector such as nickel foam filled with a predetermined amount of an active material mixture containing nickel hydroxide as a main component, and then dried, rolled, cut, or the like. It is shaped into a predetermined size through steps. In the shaping process described above, a part of the upper and lower end portions of the electrode plate 1 is compressed before being filled with the active material mixture,
The coining portion 3 having a predetermined length, width and depth is formed.

The coining portion 3 has a higher density than the surrounding electrode plate portion. Then, one of the surfaces 3a and 3b of the coining section 3 (the surface 3a in the figure).
In a), a current collecting tab 2 having a predetermined length, width and thickness is usually fixed by spot welding. Before the electrode group formed by laminating the electrode plate 1 and the negative electrode plate with the separator interposed therebetween is mounted on the coining portion 3 of the electrode plate 1 as shown in FIG. The tab 2 is focused on one side of the electrode plate group, and the focusing portion 2c is connected to a positive electrode terminal (not shown) via a lead piece.

Therefore, when assembling the battery, the tab 2 is bound, so that the tab 2 attached to the coining portion 3 is required to be in a highly flexible state. If the tab 2 is difficult to bend, the attachment end of the tab 2 may break through the separator and come into contact with the negative electrode plate, causing a short circuit accident.

Further, when the tab 2 is in a state in which it is difficult to bend, the tab 2 will bend as a whole at the welding portion of the coining portion 3 at the time of focusing, so that the tab 2 crushes the upper end of the separator and the negative electrode. The situation of contact with the board is also likely to occur, which may also cause a short circuit accident. Here, a conventional tab welding method will be described.

As shown in FIGS. 5 and 6, the tab welding device includes a positioning means 4 for fixing the electrode plate 1 at a predetermined position, and a welding means 5 composed of an upper electrode 5a and a lower electrode 5b.
A cutting means 6 including a movable cutting blade 6a and a fixed cutting blade 6b, and a sheet feeding means for intermittently feeding a long sheet 2a for a tab to a coining portion 3 of an electrode plate 1 positioned by a positioning means 4. 7 and 7 are arranged in series in this order. In this device, the end surface of the upper electrode 5a is a smooth surface having a substantially circular shape, and the end surface of the lower electrode 5b is a smooth surface having an elongated rectangular shape, and the coining portion 3 is formed at the end surface of the lower electrode 5b. Supporting the lower surface 3b of the upper electrode 3 and supporting the lower electrode 3 on the upper end 3b disposed on the upper surface 3a.
Spot welding can be performed by pressing the end face of a. Therefore, in this case, the upper electrode 5a functions as a spot welding electrode and the lower electrode 5b functions as a supporting electrode. In a normal device, the movable cutting blade 6a is arranged on the lower side, and the long sheet 2a intermittently supplied from the sheet supply means 7 passes through the inside of the fixed cutting blade 6a and has a predetermined length at its tip. Is arranged in the coining section 3.

In carrying out the welding operation, first, the electrode plate 1 is fixed to the positioning means 4 with the coining portion 3 of the electrode plate 1 protruding from the end of the positioning means 4 by a predetermined length. Then, the sheet feeding means 7 is operated to send out the long sheet 2a by a predetermined length, and the leading end portion 2b thereof.
Is arranged at the position of the coining portion 3 of the electrode plate 1. In this case, conventionally, the leading end portion 2b of the long sheet 2a is usually arranged on the upper surface 3a side of the coining portion 3 as shown in FIG. The distance between the surface 3a of the coining portion 3 and the leading end portion 2b of the long sheet is usually set to about 1 to 3 mm.

Then, the upper electrode 5a and the lower electrode 5b are connected to each other from the leading end 2b of the long sheet 2a to the upper surface 3a of the coining portion 3.
Then, the tip end portion 2b is welded to the coining portion 3 by pressure welding to at least one spot. Then, the movable cutting blade 6a is moved upward as shown by an arrow in FIG. 7 while performing the spot welding described above or when the spot welding is completed.

The long sheet 2a is plastically deformed and cut by the shearing force generated between the movable cutting blade 6a and the fixed cutting blade 6b, and the tip portion 2 welded to the coining portion 3 is cut.
b is separated as a tab 2 having a predetermined length. At this time,
As shown in FIG. 8, the leading end portion 2b of the long sheet 2a is
Upper and lower electrodes 5a, point (spot welds) which is pressed against at 5b about the P ₁ curved pushed upward by the movable cutting blade 6a, is cut through the yield point. Therefore, when the cutting is completed, the separated tip portion 2b (tab) has undergone work hardening.

Therefore, the cut tip portion 2b, that is, the tab 2 is welded and fixed to the coining portion 3 in a state where the cut portion is bent upward. From such a thing,
Next, with respect to the electrode plate 1, the tab 2 and the coining portion 3 where the tab 2 is welded are further pressed to form the tab 2
The above-mentioned warp is corrected.

[0012]

By the way, if the degree of work hardening at the tip portion 2b of the long sheet 2a after cutting, that is, the tab 2 is large, the flexibility is deteriorated. Such inconvenience is likely to occur. Therefore, it is preferable that the tab 2 after cutting be as flexible as possible.

Work hardening that occurs during cutting is rate-controlled by the amount of plastic deformation of the material to be cut. Generally, if the amount of plastic deformation is small, the degree of work hardening is small, and in the opposite case, the work hardening is large. Therefore, in the production of the battery electrode plate 1 described above, in order to facilitate the work of concentrating the tabs 2 and to reduce the occurrence of a short-circuit accident at the time of converging, in order to reduce the occurrence of a short-circuit accident, the plasticity of the tip 2b of the long sheet 2a is cut. It would be preferable to reduce the amount of deformation.

The present invention has been made based on the above idea, and the amount of plastic deformation (warpage) of the tab 2 can be reduced in the cutting process after the completion of tab welding, so that a short circuit occurs even during focusing work. An object of the present invention is to provide a tab welding device for obtaining a battery electrode plate that is less likely to cause an accident and a method for manufacturing a battery electrode plate using the tab welding device.

[0015]

In order to achieve the above-mentioned object, in the present invention, there is provided a device for welding a current collecting tab to a coining portion of a battery electrode plate, the device comprising: Positioning means, welding means composed of an upper electrode and a lower electrode, cutting means composed of a movable cutting blade and a fixed cutting blade facing each other in the vertical direction, and a leading end portion of the tab long sheet is arranged on the surface of the coining portion. In the tab welding device for a battery electrode plate in which the sheet feeding means for arranging are arranged in series in this order, the movable cutting blade has a front surface side of the coining portion in which a tip portion of the tab long sheet is arranged. A tab welding device for a battery electrode plate, wherein the battery electrode plate having a coining portion is fixed to a positioning means for positioning; Supplying a long sheet for tabs from the means and arranging the tip of the tab on the surface of the coining section on the side of the movable cutting blade; welding the tip to the coining section while crimping the tip with upper and lower electrodes A step of driving the movable cutting blade to cut the long sheet for tabs to separate the electrode plate for a battery to which the tabs are attached; and a press work at a tab welding portion of the electrode plate for a battery. A process for manufacturing a battery electrode plate is provided, which includes a step of performing the bending correction.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An apparatus of the present invention and a method of manufacturing an electrode plate using the same will be described below with reference to the drawings. FIG.
1 is a schematic diagram showing an apparatus of the present invention. In the apparatus of FIG. 1, a positioning means 4 for the battery electrode plate 1, a welding means 5 composed of an upper electrode 5b and a lower electrode 5a, a cutting means 6 composed of a movable cutting blade 6a and a fixed cutting blade 6b, and a long tab sheet. The fact that the supply means 7 of 2a are arranged in series in this order is no different from the conventional device shown in FIGS.

However, in the apparatus of the present invention, the leading end portion 2b of the long tab sheet 2a supplied from the sheet supply means 7 is fixed to the positioning means 4 by the electrode plate 1.
Is disposed on the lower surface 3b side of the coining portion 3. And
Upper electrode (spot welding electrode) 5a shown in FIGS. 5 and 6
Is arranged below the coining portion 3, and the lower electrode (supporting electrode) 5b shown in FIGS. 5 and 6 is arranged above the coining portion 3.

Therefore, the movable cutting blade 6a is located below the tip portion 2b of the long tab sheet 2a. Then, as shown in FIG. 2, the spot welding electrode 5
a and the supporting electrode 5b, the tip 2b is attached to the lower surface 3 of the coining portion.
Spot welding is performed by pressure contact with b. When the spot welding is completed or during the spot welding, the tip 2b is cut by driving the movable cutting blade 6a upward.

At the time of this cutting, the tip portion 2b bends upward around the spot welding point P ₂ . However,
The bending of the tip portion 2b starts from the tip 3c of the coining portion, and the bending of the portion pressed against the lower surface 3b of the coining portion does not occur. Therefore, the amount of plastic deformation is smaller than that in the conventional case shown in FIG. Become. Therefore, the work hardening of the tip portion 2b after cutting, that is, the tab 2 is less than that shown in FIG. 8, and the flexibility thereof is good.

[0020]

EXAMPLE A nickel positive electrode plate 1 shown in FIG. 3 was manufactured using the apparatus shown in FIG. Nickel positive electrode plate 1 has a total length of 38.0 m.
m, overall width 13.4 mm, thickness 0.6 mm, coining part 3
Has a length of 3.5 mm, a width of 3.5 mm and a thickness of 0.15 mm. A nickel tab 2 having a length of 9 mm, a width of 3.5 mm and a thickness of 0.15 mm is spot-welded to one surface of the coining portion 3.

First, as shown in FIG. 1, the electrode plate 1 is fixed to the positioning means 4, and the long tab sheet 2a is supplied from the supply means 7 to the lower surface 3b of the coining portion 3 so that the tab-shaped long sheet 2a is approximately between them. The tip portion 2b was arranged in a state of being superposed on the lower surface 3b by about 3 mm in the longitudinal direction with an interval of about 1.5 mm. Then, the spot welding electrode 5a and the supporting electrode 5b press the tip portion 2b against the lower surface 3b of the coining portion 3 to perform spot welding, and then the movable cutting blade 6a is driven to cut the tip portion 2b having a length of 9 mm. Attached tab 2. The cutting point is about 1-2 mm upward from the tip 3c of the coining portion 3.
It was warped to some extent. Then, the coining portion 3 was pressed to correct the warp of the tab 2 to obtain the nickel positive electrode plate 1.

The nickel positive electrode plate 1 and a known hydrogen storage alloy negative electrode are laminated via a separator to form an electrode plate group, and after tabs are focused, an outer package is formed together with an alkaline electrolyte having a predetermined concentration. 2000 square nickel-hydrogen prismatic secondary batteries are housed in a can and sealed with a lid that also serves as a positive electrode terminal.
I assembled them individually. The occurrence of short circuits in 2000 secondary batteries was not observed at all.

On the other hand, using the conventional apparatus shown in FIGS. 5 and 6, a nickel positive electrode plate 1 having the same specifications is manufactured, and a prismatic nickel-hydrogen prismatic secondary battery is manufactured in the same manner as above except that it is used. 2000 pieces were assembled. A short circuit was observed in 81 batteries. In addition, the above description is for the tab long sheet 2
Although the tip portion 2b of a is arranged on the lower surface of the coining portion 3, the tip portion 2b can be arranged on the upper surface of the coining portion 3 as in the conventional case.

In that case, however, the spot welding electrode 5a should be arranged above, the support electrode 5b should be arranged below, the movable cutting blade 6a should be arranged above the tip 2b, and the fixed cutting blade 6b should be arranged below. is necessary. In short, in the case of the device of the present invention, the movable cutting blade 6a may be arranged on the coining portion 3 on the side where the tip portion 2b of the long tab sheet 2a is arranged for cutting.

[0025]

As is apparent from the above description, according to the apparatus of the present invention and the method of manufacturing an electrode plate using the apparatus,
In the obtained electrode plate, the work hardening of the tab after cutting is reduced, and the electrode plate group is configured using the electrode plate, and the tab bendability is good even if the tab focusing work is performed, The battery will not cause a short circuit accident.

This is because a movable cutting blade is arranged toward the tab long sheet arranged at the coining portion of the electrode plate to cut the tab long sheet, so that the amount of plastic deformation at the time of cutting is reduced. This is an effect based on the reduction in work hardening.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of an apparatus of the present invention.

FIG. 2 is a partially enlarged schematic view showing a state in which a long tab sheet is cut by the device of the present invention.

FIG. 3 is a perspective view showing a battery electrode plate.

FIG. 4 is a cross-sectional view showing an electrode plate group in which tabs are focused.

FIG. 5 is a schematic perspective view showing an example of a conventional tab welding device for a battery electrode plate.

FIG. 6 is a schematic view showing a state in which a long sheet for tabs is arranged in a conventional spot welding apparatus.

FIG. 7 is a schematic view showing a state in which a long tab sheet is cut by a conventional tab welding device for a battery electrode plate.

FIG. 8 is a partially enlarged view of FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrode plate 2 Tab 2a Long sheet for tab 2b Tip of long sheet for tab 2a 2c Tab focusing portion 3 Coining portion 3a Upper surface of coining portion 3b Lower surface of coining portion 3c Tip of coining portion 3 4 Battery Positioning means for electrode plate 5 Welding means 5a Upper electrode (spot welding electrode) 5b Lower electrode (supporting electrode) 6 Cutting means 6a Movable cutting blade 6b Fixed cutting blade 7 Sheet feeding means

Claims (2)

[Claims] 1. An apparatus for welding a current collecting tab to a coining portion of a battery electrode plate, which comprises a battery electrode plate positioning means, a welding means composed of an upper electrode and a lower electrode, and a vertical direction with respect to each other. To a battery electrode plate in which cutting means composed of opposed movable cutting blades and fixed cutting blades and sheet feeding means for arranging the leading end of the tab long sheet on the surface of the coining portion are arranged in series in this order. In the tab welding apparatus, the movable cutting blade is located on the front surface side of the coining portion in which the tip portion of the long tab sheet is arranged. apparatus. 2. A step of fixing a battery electrode plate having a coining portion to a positioning means for positioning; feeding a long tab sheet from a sheet feeding means, the leading end portion of which is a movable cutting blade. Step of arranging on the surface of the coining portion on the side; welding the tip portion to the coining portion while crimping the tip portion with the upper and lower electrodes; driving the movable cutting blade to cut the long sheet for tabs And a step of separating the battery electrode plate to which the tab is attached; and a step of pressing the tab welding portion of the battery electrode plate to correct the bend, and the electrode for battery. Method of manufacturing a plate.