JPH0799043A - Manufacture of square sealed storage battery - Google Patents

Abstract

PURPOSE:To reduce the generation of a poor welding and to improve the productivity by making the four sides of the connecting part of a battery container and a battery lid in separate straight lines, and welding them separately by using a laser beam. CONSTITUTION:Batteries A in the condition fitting battery lids 2 to the openings of battery containers 1 are lined up continuously on a conveyer moving at a constant speed. A laser beam is radiated to the connecting parts of the containers 1 and the lids 2 through a focus lens so as to weld and seal them, while moving the batteries A in the direction of the arrow. In this case, by dividing the laser beam into two by a beam splitter at the near side of a lens, and radiating to two parallel sides of the four sides of the connecting part, the productivity can be improved further. When the welding of the longer sides is finished, the postures of the batteries are converted, and the shorter sides are welded in the same manner. Consequently, it is not necessary to slow down the speed at the corners compared with a one stroke welding, the density of the welding bead is made constant, and the welding quality is improved.

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 prismatic sealed storage battery, and more particularly to an improvement in a method for welding a joint between a battery container and a battery lid.

[0002]

2. Description of the Related Art Conventionally, in welding a joint portion between a battery container and a battery lid of a prismatic closed type storage battery, JP-A-64-3
As disclosed in Japanese Patent Publication No. 954, since the joint portion between the battery container and the battery lid is continuously welded over the entire circumference, the battery is XY
Move it on the table (that is, move the table on which the battery is placed linearly when welding one side of the above-mentioned joint, and move the table on which the battery is placed first when welding the next adjacent side. (Or moved in the direction orthogonal to the moving direction), or the emission side of the laser beam was moved in the XY directions.

Therefore, due to acceleration and deceleration due to the moment of inertia of the XY table, the weld beads (welded portion continuous in a bead shape) are likely to be coarse and dense, resulting in defective welding and eventually leakage of the electrolytic solution. was there.

Further, in order to weld the four corners to the same extent as the straight line portion, the welding speed of the straight line portion must be suppressed to a low speed of about 7 to 12 mm / sec in accordance with the welding speed of the corner portion. Therefore, the ability of an expensive laser welding machine cannot be fully utilized, resulting in a lack of productivity and an increase in production cost.

[0005]

As described above, in the production of the conventional prismatic sealed storage battery, welding failure is likely to occur, and the ability of the laser welder cannot be fully utilized in the welding. However, there was a problem that the productivity was low and the production cost was high.

Therefore, the present invention solves the above-mentioned problems in manufacturing a conventional prismatic sealed storage battery,
It is an object of the present invention to provide a method for manufacturing a prismatic sealed storage battery with less welding defects and high productivity.

[0007]

DISCLOSURE OF THE INVENTION The present invention relates to welding of a joint portion between a battery container and a battery lid of a prismatic closed type storage battery.
The above object is achieved by welding the four sides of the joined portion as separate straight lines, rather than welding the entire circumference continuously in a so-called single stroke.

That is, according to the present invention, since the four sides of the joint portion of the battery container and the battery lid are divided into separate straight lines and welded, the moving speed of the battery can be made constant, and as a result, the welding bead can be obtained. Is eliminated, the density of the weld beads becomes constant, and defective welding is prevented.

Further, since the four sides of the joining portion of the battery container and the battery lid are divided into separate straight lines and are welded as described above, the welding speed of the whole is reduced in accordance with the welding of the corners. Since it is no longer necessary to keep the battery in place, the moving speed of the battery can be increased according to the ability of the laser welding machine, and more than one battery can be arranged in a row during welding. It is possible to significantly reduce the time required for origination of the laser oscillator, and it is possible to improve productivity.

Further, if the laser beam is divided into two by the beam splitter and two parallel sides of the four sides of the joint portion are simultaneously irradiated and welded, the welding length per unit time can be increased. Therefore, the productivity can be further improved.

In the present invention, since the four sides of the joint portion between the battery container and the battery lid are divided into separate straight lines and welded, it is necessary to explain how the corners are welded. However, in a normal small battery, even if the R (R) of the corner is large, it is about 0.2 mm, the width of the tip of the laser beam is about 0.5 mm, and the width of the laser beam is wider. Even if the four sides are divided into separate straight lines and welded, the corners can be sufficiently welded.

[0012]

Embodiments of the present invention will now be described with reference to the drawings. However, the present invention is not limited to the examples illustrated in the embodiments.

FIG. 1 is a schematic perspective view showing an example of a prismatic sealed storage battery according to the present invention. In the figure, reference numeral 1 denotes a battery container made of a nickel steel plate. In this battery container 1, a positive electrode plate wrapped in a separator is sandwiched by a negative electrode plate and laminated so that a negative electrode plate is arranged on the outermost side. The electrode plate group and the electrolytic solution are contained, and the battery lid 2 is fitted into the opening. The central projecting portion of the battery lid 2 is the terminal 2a, which is the positive electrode side terminal in this embodiment.

The planar shape of this battery is rectangular.
The long side has a length of 17 mm and the short side has a length of 6 mm. After the battery lid 2 is fitted into the opening of the battery container 1 as described above, the battery container 1 and the battery lid 2 are joined together. A complete battery is made by welding and sealing the parts with a laser beam as shown below.

FIG. 2 is a plan view showing a state in which the joint portion between the battery container 1 and the battery lid 2 is welded in manufacturing the prismatic sealed storage battery of the present invention, and FIG. 3 is a side view thereof.

First, the battery A with the battery lid 2 fitted in the opening of the battery container 1 is placed on a conveyor (not shown) which moves linearly at a constant speed, and the battery A is placed as shown in FIG. Are arranged continuously. Then, as shown in FIG. 3, while moving the battery A in the direction of the arrow, the laser beam 3 is focused by the condenser lens 4
Irradiate the joint between the battery container 1 and the battery lid 2 via
Weld and seal.

At that time, a laser beam is divided into two by additionally arranging a beam splitter in the portion in front of the condenser lens 4, and laser beams having the same intensity are simultaneously formed at two points, that is, parallel to the four sides of the joint portion. It is also possible to irradiate the two sides to be irradiated, and by doing so, the productivity can be further increased.

Then, as shown in FIG. 2, when the long side of the joint between the battery container 1 and the battery lid 2 is welded, the batteries are rearranged so that the short side of the joint can be laser-welded. Similarly, while moving linearly, weld and seal. On the contrary, it is of course possible to laser-weld the long side first of the short side of the joint portion between the battery container 1 and the battery lid 2 first.

Table 1 shows the results of examining the occurrence of welding defects during welding by the method shown in the above embodiment and the conventional method (that is, the method of continuously welding all four sides in a single stroke). Shown in.

[0020]

[Table 1]

The laser output is 10 in both the embodiment and the conventional method.
It is 0 W, which is the same.

The welding speed in the embodiment was 14 mm / sec, and the time required for welding one battery was 5 seconds including the alignment of the batteries and the origination of the laser oscillator.
In the conventional method, the welding speed was 8 mm / sec, and it took 12 seconds to weld one battery because it took time to align the individual batteries and find the origin.

Further, as shown in Table 1 above, in the conventional method, although the welding was slow, the defective welding rate was as high as 10%. Despite being short, there were no welding defects at all. In addition, most of the places where welding defects were generated by the conventional method were corners. As described above, it is considered that the welding defects are concentrated on the corners because of a mismatch between the moment of inertia of the XY table on which the battery is mounted and the activation of the motor for moving the table.

[0024]

As described above, according to the present invention, since the four sides of the joint portion of the battery container and the battery lid are divided into separate straight lines and welded, a laser beam is used for welding the joint portion. Can be irradiated at a constant speed, as a result, the densification of the welding beads is eliminated, the density of the welding beads becomes constant, welding defects are prevented from occurring, and welding quality can be improved. became.

Further, according to the present invention, since the four sides of the joint portion between the battery container and the battery lid are divided into separate straight lines and welded, the overall welding speed can be adjusted in accordance with the welding of the corners. Since it is no longer necessary to keep the welding speed low, the welding speed can be increased, and moreover, it has become possible to arrange multiple batteries in series during welding. It has become possible to significantly reduce the time required for the origin search, improve productivity, and as a result, provide a prismatic sealed storage battery at low cost.

According to the conventional method, when welding the joint between the battery container and the battery lid is continuously performed in a single stroke with a single stroke, the welding speed must be kept low in accordance with the welding of the corners. Therefore, it depends on the shape and size of the battery, but the welding speed is 7 to 12 mm / sec, and it takes time to align each battery and find the origin of the laser oscillator. It took 8 to 12 seconds, but in the case of the present invention, the welding speed is improved by about 20%, and the welding speed becomes 10 to 15 mm / second, although it depends on the shape and size of the battery. The time required to find the origin of the laser oscillator can be greatly reduced, so the time required to weld one battery is 4-8.
It can be shortened to seconds.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an example of a prismatic sealed storage battery according to the present invention.

FIG. 2 is a plan view showing a state in which a joint portion between a battery container and a battery lid is welded in the present invention.

FIG. 3 is a side view showing a state in which the joining portion between the battery container and the battery lid is welded in the present invention.

[Explanation of symbols]

 1 battery container 2 battery lid 2a terminal

Claims (2)

[Claims] 1. A battery lid 2 having a terminal 2a of one of the electrodes on an upper portion thereof is fitted into an opening of a battery container 1 having a quadrangular cross section in which a power generating element is housed, and then the battery container 1 is formed. In the manufacture of a prismatic sealed storage battery in which the joint portion with the battery lid 2 is welded and sealed with a laser beam, four sides of the joint portion between the battery container 1 and the battery lid 2 are divided into separate straight lines and welded with the laser beam. A method for manufacturing a prismatic sealed storage battery, comprising: 2. The method for manufacturing a prismatic sealed storage battery according to claim 1, wherein two parallel sides are welded at the same time.