JP3069761B2 - Manufacturing method of prismatic sealed battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a sealed rectangular battery.

[0002]

2. Description of the Related Art Nickel-metal hydride batteries (nickel-cadmium secondary batteries) have been replaced by nickel-metal hydride batteries. The nickel-metal hydride battery has a higher energy capacity per unit volume than the nickel-cadmium battery, and has various characteristics comparable to those of the nickel-cadmium battery.

[0003] Incidentally, ordinary nickel-cadmium batteries and nickel-metal hydride batteries have a cylindrical shape and therefore have a poor storage efficiency when stored in equipment. In particular, cordless equipment that is reduced in size and weight is a major problem. Is coming.
For this reason, rectangular batteries designed to increase the storage efficiency in devices have been used. The rectangular sealed battery has a flat rectangular parallelepiped shape as shown in FIG. 6, for example, the height is the same height as the cylindrical battery, the long side 1a is the same length as the diameter of the cylindrical battery, and the short side 1b is long. It is １ ／ of the length of the side surface 1a, and is formed to have a size corresponding to a space for accommodating one cylindrical battery when three are arranged. Then, the power generating element is inserted into the outer can 1, and after the electrolyte is injected, the sealing body 2 is fitted and attached to the rectangular upper opening end 1c, and the entire periphery is welded to form a sealed structure. .

The sealing body 2 is fitted and mounted on a rectangular cover plate 3 at the center of the cover plate 3 via an insulating packing (gasket) 4, and the lower end is connected to an anode current collector of a power generating element. Rivet (not shown) fixed to the lid plate 3 together with the lead plate
The anode cap 5 is welded and fixed to the upper surface of the rivet, and has a gas escape hole 5a at each lower end of each side face facing each long side face 1a, and a safety valve built in the anode cap 5 and the like. ing.

As a method of welding the outer can 1 and the cover plate 3 of the sealing body 2, seam welding and arc welding have been widely performed, but the influence of heat on a power generating element, a gasket, etc. in the vicinity of a welded portion is considered. In recent years, a pulse-type laser welding method suitable for fine processing has been adopted in order to suppress this. Here, as the welding conditions, the penetration depth is 0.15 mm or more (for example, Japanese Patent Publication No. 4-196049), and the welding position is the outer can 1
Is welded at the center of the gap between the fitting ends of the opening end of the sealing body 2 and the cover plate 3.

[0006]

However, the method of welding the center of the gap between the opening end of the outer can 1 and the cover plate 3 of the sealing body 2 is a method of welding the outer can 1 and the sealing body 2. although the strength is improved, in order to weld the cover plate 3 is close to the insulating packing 4 on the long side surface 1a of the outer can 1, by the influence of heat during welding, insulation packing 4 ends up deteriorating, There is a problem that the internal electrolyte leaks and may damage equipment incorporating the battery.

The present invention has been made in view of the above points, and a method of manufacturing a sealed rectangular battery in which the influence of heat on an insulating packing during welding between an outer can and a sealing body is reduced to prevent deterioration. The purpose is to provide.

[0008]

According to the present invention, in order to achieve the above object, a power generating element is housed in a rectangular outer can,
A rectangular sealed battery in which a sealing body provided with an anode cap having a built-in safety valve is fitted and mounted on a cover plate via an insulating packing, and the fitting portion between the opening end of the outer can and the lid is sealed by laser welding. In the manufacturing method, the welding position of the opening end and the lid is shifted by 0.05 mm to 0.07 mm outside the fitting portion only in the vicinity of the insulating packing.

[0009] In laser welding, it is preferable that the penetration depth is 0.15 mm or more in any of the welded portions by changing the output of the portion where the welding position is shifted outward and the output of the other welded portions.

[0010]

When the long side opening end of the outer can is laser-welded to the sealing body, the welding position should be at least near the insulating packing.
Only the outside is shifted by 0.05 mm to 0.07 mm, and the penetration depth is set to 0.15 mm or more. This prevents the insulation packing from deteriorating due to the heat effect at the time of laser welding, and prevents leakage of the electrolyte from the welded sealing portion.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the accompanying drawings. The same members as those in FIG. 4 are denoted by the same reference numerals. 1 and 2 show an upper cross section of a rectangular sealed battery to which the present invention is applied. The outer can 1 has a rectangular parallelepiped shape, and the open end 1a has a rectangular shape. A sealing body 2 is fitted and mounted on the opening end 1a of the outer can 1, and the opening end 1a and the sealing body 2 are seam-welded all around by laser welding to form a closed structure. The outer can 1 is integrally formed of, for example, stainless steel or a nickel-plated steel plate.

The sealing body 2 is fitted in a liquid-tight manner through a cover plate 3 and a hole 3 a formed in the center of the cover plate 3 via an insulating packing 4.
GoSo is deposited, the lower end is caulked to the cover plate 3 with one end of the lead plate 7 where the anode current collector of the power generating element 6 is connected, the rivet 8 small holes 8a is formed in the center, the rivet 8 An anode cap 5 having a gas escape hole 5a provided substantially at the center of each lower end of each side face facing the long side surface 1a of the outer can 1 and fixed to the upper side, and a hole of a rivet 8 built in the anode cap 5 8a is constituted by a safety valve 9 and the like. The lid plate 3 is also formed of a stainless steel plate or a nickel-plated steel plate 1 like the outer can 1.

Hereinafter, a method of welding the outer can 1 and the cover plate 3 of the sealing body 2 will be described. The fitting portion between the short side 1b side of the opening end 1c of the outer can 1 and the cover plate 3 of the sealing body 2 is shown in FIGS.
As shown in (2), the distance from the gasket 4 is long, and the insulating packing 4 is hardly affected by heat during welding. Therefore, there is no particular problem in welding the portion by scanning the center of the fitting portion with the laser beam L. The laser beam L is a pulsed laser beam.

The fitting portion between the long side surface 1a side of the open end 1c of the outer can 1 and the cover plate 3 of the sealing body 2 has a short distance from the insulating packing 4 as shown in FIGS. The insulating packing 4 is easily affected by heat during welding. Therefore, when welding the portion, the laser beam L is directed outward by a predetermined distance W from the center of the fitting portion, that is, the insulating packing 4
To scan the position away from. Weld bead 1 at this time
The depth h of the penetration of 0 is 0.15 mm or more. here,
The penetration depth h refers to the depth from the open end 1c of the outer can 1 and the upper surface of the lid 3 to the welded portion at the contact portion between the inner surface of the open end 1c and the end surface of the lid 3.

FIG. 5 summarizes the relationship between the deviation w of the welding position and the rate of occurrence of liquid leakage failure at the peripheral portion of the insulating packing 4 and the welded sealing portion. If the deviation of the welding position w is less than 0.05 mm, However, the rate of occurrence of liquid leakage at the sealing weld portion disappears, but the insulating packing 4 and the like are deteriorated due to the influence of heat during laser welding, and the rate of occurrence of liquid leakage increases, which may lead to liquid leakage. In addition, when the displacement of the welding position w exceeds 0.08 mm, the rate of occurrence of liquid leakage at the insulating packing 4 disappears, but a sufficient penetration depth cannot be obtained even if the output of the laser beam L is increased. The rate of liquid leakage at the sealing portion increases, and there is a possibility of liquid leakage.

Therefore, as is apparent from FIG. 5, it is preferable that the displacement w to the outside of the welding position be in the range of 0.05 to 0.07 mm and the penetration depth h be in the range of 0.15 mm or more. still,
In the laser welding, the penetration depth h is set to 0.15 mm or more in any of the welded portions by changing the output of the portion where the welding position is shifted outward and the output of the other welded portion.

The welding position on the long side 1a is
At least the vicinity of the insulating packing 4 may be shifted, and it is not necessary to shift the entire length of the long side surface 1a. FIG.
, Indicates the rate of liquid leakage at the welded seal,
The marks indicate the rate of occurrence of liquid leakage at the insulating packing 4 part. Also, the batteries in the manufacturing method according to the present invention are A, B, and C, and the batteries according to the conventional manufacturing method in which the welding position is not shifted in the vicinity of the insulating packing 4 are D, and n = 100 prototypes are manufactured and subjected to an overcharge test. Table 1 shows the results of comparing the rates of occurrence of liquid leakage failures in the peripheral portion of the insulating packing and the welded sealing portion. As is evident from Table 1, no battery leakage defect was observed in the battery manufactured by the manufacturing method according to the method of the present invention.
The battery prototyped by the conventional manufacturing method exhibited a liquid leakage defect of about 33% due to the deterioration of the insulating packing.

[0018]

[Table 1]

[0019]

As described above, according to the present invention, it is possible to eliminate the thermal influence of the insulating packing when welding the sealing body to the outer can, prevent deterioration, and manufacture a highly reliable square sealed battery. There is an effect that it becomes possible to do.

[Brief description of the drawings]

FIG. 1 is a top cross-sectional view including an anode cap of a prismatic sealed battery according to the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is an enlarged view of a welding portion of FIG. 1;

FIG. 4 is an enlarged view of a welded portion of FIG. 2;

FIG. 5 is a graph showing the welding position shift of FIG. 4, the rate of occurrence of liquid leakage at the gasket, and the rate of occurrence of liquid leakage at the welded seal.

FIG. 6 is a top perspective view showing welding of a fitting portion between an opening end of an outer can of a rectangular sealed battery and a sealing body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer can 2 Sealing body 3 Cover plate 4 Gasket 5 Anode cap 5a Notch 6 Power generation element 8 Rivet 9 Safety valve 10 Weld bead

 ──────────────────────────────────────────────────続 き Continuing from the front page Judge of the colleague Judge Shun Seibu Judge Junji Yuda Judge Keiji Fujiwara Judge Katsuyoshi Yamagishi Judge Shuzo Tanabe (56) Reference JP 3-295156 (JP, A) JP 60-56358 (JP, A) JP-A-4-196049 (JP, A)

Claims (2)

(57) [Claims] 1. A power generation element is housed in a rectangular outer can, and a sealing body provided with an anode cap having a built-in safety valve is fitted and mounted on a cover plate via an insulating packing, and an opening end of the outer can and the lid are provided. In the method for manufacturing a sealed rectangular battery in which a fitting portion with a body is sealed by laser welding, a welding position between the open end and the lid is located outside the fitting portion only near the insulating packing.
A method for producing a prismatic sealed battery , characterized in that welding is performed with a displacement of 0.05 mm to 0.07 mm. 2. The laser welding has a penetration depth of 0.15 mm in any of the welded portions by changing the output of a portion in which the welding position is shifted outward and the output of another welded portion.
2. The method for manufacturing a prismatic sealed battery according to claim 1, wherein: