JP2000090908A - Sealed storage battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealed storage battery with high productivity, high airtightness, high electrolyte leakage resistance, and high reliability. SOLUTION: In this sealed storage battery in which a positive terminal is welded to a head of a hollow rivet having the head and a hollow shaft integratedly formed with the head, and a sealing body is formed by fixing the hollow rivet to a sealing plate through a lead piece to be connected to a positive current collector by caulking the tip of the hollow shaft, an insulating plate, and a gasket, the lead piece has two surfaces formed by bending a thin plate, and when the length from the center of a hole 17d into which the hollow shaft of the hollow rivet is inserted to a bending line A takes 1, the length from the center of the hole 17d to the end B is 0.5-1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed storage battery, and more particularly to a sealed storage battery provided with a sealing body in which a hollow rivet is attached to a sealing plate via a lead piece, an insulating plate and a gasket. The present invention relates to a sealed storage battery having characteristics.

[0002]

2. Description of the Related Art Conventionally, in sealed batteries such as nickel-cadmium batteries and nickel-metal hydride batteries, in particular, in these small rectangular sealed batteries, a positive electrode terminal also serving as a safety valve is attached to a sealing plate via an insulating gasket. 2. Description of the Related Art There is known a battery that is attached to an opening of a battery container by laser welding.

More specifically, a small rectangular sealed storage battery 1 as shown in FIG. 1 has a flat rectangular parallelepiped shape, and the storage battery includes a power generation element (electrode group) in an outer can (battery container) 2. )
Is inserted, the electrolyte is injected, and the spacer is placed. Then, the sealing body 3 is fitted to the upper open end of the outer can 2, and the entire periphery is laser-welded to form a sealed structure.
As shown in FIG. 7, the sealing body 3 includes a metal positive electrode terminal cap 11, a rubber valve body 12, a metal hollow rivet 13,
It is composed of a resin gasket 14, a metal sealing plate 15, a resin insulating plate 16, a metal lead piece 17 (also serving as a washer), and the like.

The positive terminal cap 11 is provided with a hollow rivet 1.
3 is welded to the head. At the lower end of each side surface of the positive electrode terminal cap 11, a notch 11 serving as a gas escape path is provided.
a is provided. The valve body 12 is provided with the positive electrode terminal cap 1
The hole 13d formed in the hollow shaft 13b of the hollow rivet 13 built in 1 is closed. When the internal pressure of the storage battery rises abnormally for some reason and exceeds a predetermined pressure, the valve body 12 is opened by the gas pressure applied through the hole 13d of the hollow rivet 13, and the gas in the outer can is released from the positive electrode terminal cap 1.
The internal pressure of the storage battery is reduced by discharging the battery 1 to the outside through the notch 11a. The gasket 14 is used for the sealing plate 1 on the negative electrode side.
5 and the hollow rivet 13 on the positive electrode side to ensure electrical insulation, and also to ensure leakage resistance and airtightness of the electrolyte injected into the outer can. The insulating plate 16 is interposed between the lead piece 17 and the sealing plate 15 to secure electrical insulation.

[0005] By the way, the shape of the conventional lead piece is, for example, in the case of a small rectangular sealed storage battery 1 as shown in FIG.
As shown in FIG. 8, a thin plate having a thickness of 0.3 mm has two surfaces formed by bending, and a hole 17d having a diameter slightly larger than the outer diameter of the hollow shaft through which the hollow rivet is inserted is provided on one surface 17a. The remaining one surface 17b is connected to the current collector.
The lead piece also serves as a washer, and has a shape in which a rectangular thin plate is connected to the washer. The length from the center of the hole 17d to the bent line A is 5.5 mm (size ratio 1), and the length from the center of the hole to the opposite end B is 2 mm (size ratio 0.3).
6). The outer diameter of the washer part is 4 mm, and the length of the rectangular part connected to the washer part in the short direction is 3 mm.
It is. The surface 17b on the current collector connection side has a length in the long direction of 3 mm and a length in the short direction of 3 mm.

[0006] As a method of manufacturing the sealing body 3, Japanese Patent Laid-Open No.
A method described in JP-A-335190 is known. That is, in order to manufacture the sealing body 3, as shown in FIG. 4, the hollow rivet 13, the gasket 14, the sealing plate 15, the insulating plate 16, and the lead piece 17 are assembled.
Invert the lower end 13c of the hollow rivet 13 with the punch 2
1, the lead piece 17 and the insulating plate 16 are sealed with the sealing plate 1
5 and fix it. Next, as shown in FIG.
The negative electrode rod 23 having a circular cross section is brought into contact with the open rivet lower end portion 13c while applying pressure to the open rivet lower end portion 13c. And apply a voltage between the positive and negative electrodes,
The welding projection 11b on the back surface of the positive electrode terminal cap is welded to the head of the hollow rivet.

However, in the prior art, when the diameter of the lower end of the rivet is increased and the lead piece 17 and the insulating plate 16 are caulked and fixed to the sealing plate 15, the shorter the distance from the center of the hole of the lead piece 17 to the end is, the larger the length is. The lower end of the rivet portion may not be able to withstand the squeezing force, and the lower end of the rivet portion may be too open, causing the rivet lower end 13c to expand unevenly as shown by the dotted line in FIG. While the lower end of the rivet is unevenly enlarged, the hollow rivet 13 is
When the back of the positive electrode terminal cap is welded to the head of the rivet, the lower part of the rivet cannot be evenly pressed, causing the rivet to hit one side and the current flow to deteriorate, resulting in insufficient welding and poor welding, causing the positive electrode terminal cap to come off. Become.

Further, the diameter of the lower end of the rivet is increased to increase the lead piece 1
When caulking and fixing to the sealing plate 15 together with the insulating plate 7 and the insulating plate 16, both ends of the lead piece 17 and the insulating plate 16 around the rivet are likely to warp upward. The warpage of the lead piece 17 and the insulating plate 16 at this time is larger in a portion where the distance from the hole 17d of the lead piece 17 to the end is short. When a sealing body obtained by using an insulating plate whose end is warped and deformed is transported to the next step by a feeder, the sealing body is caught inside the feeder, causing a problem such as a reduction in productivity due to a stop of an assembly line. Further, in the production of a storage battery, the sealing body 3 is fitted into an outer can (battery container) 2 into which an electrode plate group or the like is inserted, but if a sealing body using a deformed insulating plate is used, the deformed insulating plate becomes a spacer. As a result, laser welding becomes insufficient due to the inability to fit tightly, which also causes problems such as liquid leakage.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and comprises a sealed storage battery, in particular, a hollow rivet attached to a sealing plate via a lead piece, an insulating plate and a gasket. An object of the present invention is to provide a sealed storage battery which can be manufactured with high productivity, has excellent airtightness and liquid leakage resistance, and has high reliability in manufacturing a sealed storage battery provided with a sealing body.

[0010]

According to the present invention, there is provided a hollow rivet having a head and a hollow shaft integrally formed with the head, a positive electrode terminal cap is welded to the head,
In a sealed storage battery provided with a sealing member attached to a sealing plate via a lead piece connected to the positive electrode current collector, an insulating plate and a gasket by caulking the tip of the hollow shaft,
The lead piece has two surfaces formed by bending a thin plate, one surface of which is provided with a hole through which a hollow rivet is inserted, and the other surface is connected to a current collector, In the longitudinal direction of the surface having the hole, when the length from the center of the hole to the bending line is 1, the length from the center of the hole to the opposite end is 0.5 to 1. It is intended to provide a type storage battery.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As a sealed storage battery of the present invention, a small rectangular sealed storage battery 1 having a flat rectangular parallelepiped shape as shown in FIG. 1 will be described, but the present invention is not limited to this embodiment. As shown in FIG. 2, the sealed storage battery 1 of the present invention has an electrode plate group inserted into the outer can 2, an electrolytic solution is injected, and the spacer 18 is placed thereon. The sealing body 3 is fitted, and the entire circumference is laser-welded to form a closed structure. The outer can 2 can be made of a material that is usually used as a battery outer can, and examples thereof include a nickel-plated steel plate.

Referring to FIG. 7, for example, in the sealing body 3 of the sealed storage battery 1, the sealing plate 15 is a metal lid, and an elliptical recess is formed at the center of the upper surface thereof. A hole 15d for attaching the gasket 14 and the hollow rivet 13 is provided concentrically with the concave portion.
The hollow rivet 13 is swaged at its lower end via a gasket 14, an insulating plate 16 and a lead piece 17 to form a sealing plate 15
And functions to maintain the airtightness of the sealed storage battery 1. The material of the hollow rivet 13 is not particularly limited as long as each member can be fixed by caulking, and examples thereof include nickel-plated iron, and more preferably nickel-plated iron. And soft iron. The hollow rivet 13 has a head 13a that is substantially flush with the sealing plate 15 when assembled with the hollow shaft 13b.
, Lower end portion 13c expanded by caulking
In consideration of the above, an appropriate shape is used. As shown in FIG. 5, the positive electrode terminal cap 11 has a flange 11 c having the same shape as the head 13 a of the hollow rivet 13. Fixed to Generated inside the sealed storage battery 1 on the side surface of the positive electrode terminal cap 11,
A notch portion 11a serving as an escape path for gas discharged from the valve body 12 is provided.

When the gas generated inside the sealed storage battery 1 exceeds a predetermined pressure, the valve body 12 opens the valve and discharges the gas to keep the internal pressure of the sealed storage battery 1 constant. The valve element 12 is not particularly limited as long as it fulfills the above function, and examples thereof include a rubber valve element. The gasket 14 and the insulating plate 16 are connected to the sealing plate 15 on the negative electrode side by the hollow rivet 13 and the lead piece 17 on the positive electrode side.
In addition, it functions to secure electrical insulation between the electrodes and prevent leakage of the electrolyte solution injected into the outer can 2. Gasket 14
The insulating plate 16 is not particularly limited as long as it insulates electricity, is not deteriorated by an electrolytic solution, and can maintain airtightness. For example, plastic or rubber having a surface coated with a sealing material is used. Is mentioned. Preferably, it is a nylon resin.

The lead piece 17 is connected to the positive electrode current collector of the power generation element, electrically connects the positive electrode terminal to the power generation element, and functions as a washer when caulking the hollow rivet 13. The shape of the lead piece in the present invention is, for example, as shown in FIG. 3, the small rectangular sealed storage battery 1 has two surfaces formed by bending a thin plate having a thickness of 0.3 mm as shown in FIG. A hole 17d having a diameter slightly larger than the outer diameter of the hollow shaft is opened, and the other surface 17b is connected to a current collector. The lead piece also serves as a washer, and has a shape in which a rectangular thin plate portion is opposed to two places of the washer. The length from the center of the hole 17d to the bent line A is 5.5 mm (size ratio 1), and the length from the center of the hole to the opposite end B is 2.75 to 5.5 mm (size ratio 0. 5). 5-1). The outer diameter of the washer portion is 4 mm, and the length of each rectangular portion in the short direction is 3 mm.
It is. The surface 17b on the current collector connection side has a length of 3 in the longitudinal direction.
mm, and the length in the short direction is 3 mm. When the sealing body is manufactured using a lead piece having such a shape, warpage of both ends of the lead piece and the insulating plate hardly occurs when the sealing body is fixed by caulking. As the lead piece 17, a conductive thin plate is used, and preferably, a nickel foil or a nickel-plated thin plate is used.

The sealed storage battery 1 according to the present invention is, for example,
Referring to FIG. 7, first, the gasket 14 is mounted on the sealing plate 15. An oval recess 15b is formed at the center of the upper surface of the sealing plate 15, and a hole 15d is formed concentrically with the recess 15b. The gasket 14 has an outer diameter slightly smaller than the hole 15 d of the sealing plate 15 and an inner diameter slightly larger than the outer diameter of the hollow shaft 13 b of the hollow rivet 13, and the gasket 14 is integrally formed on the upper peripheral edge of the cylindrical portion 14 b. It has a flange portion 14a that is formed and has an elliptical shape substantially the same as the sealing plate 15 in outer diameter. After inserting the cylindrical portion 14b of the gasket 14 into the hole 15d of the sealing plate 15, the hollow shaft 13b of the hollow rivet 13 is connected to the cylindrical portion 14 of the gasket 14.
b. As a result, the hollow rivet 13 is inserted into the hole 15d of the sealing plate 15 via the gasket 14, but the procedure is as follows.
It goes without saying that after the 3b is inserted into the cylindrical portion 14b of the gasket 14, these may be inserted into the hole 15d of the sealing plate 15.

Next, as shown in FIG. 4, these are turned upside down and mounted on the hollow rivet 13 such that the head 13a of the hollow rivet 13 contacts the pedestal 22.
A nylon insulating plate 16 and a lead piece 17 are externally fitted to the hollow shaft 13b in this order. The insulating plate 16 is interposed between the sealing plate 15 and the lead piece 17 to ensure their insulation, and has a substantially rectangular shape in plan view. A hole 16 d having a diameter slightly larger than the outer diameter of the cylindrical portion 14 b of the gasket 14 is formed in the center of the insulating plate 16, and the hollow shaft 1 of the hollow rivet 13 is formed in this hole.
3b is inserted. The lead piece 17 is as described above, and has a hole 17 slightly larger in diameter than the outer diameter of the hollow shaft 13b.
The hollow shaft 13b is inserted through d. The hollow rivet 13 in which the above members are fitted is caulked using a punch 21. The punch 21 has a conical surface formed at the distal end, and the diameter of the distal end of the hollow rivet is increased by the conical surface.

Next, as shown in FIG. 5, a positive electrode terminal cap 11 accommodating a rubber valve element 12 therein and also serving as a safety valve device is mounted on the head 13a of the hollow rivet 13 which has been caulked. The projection 11b is welded to form the sealing body 3. As shown in FIG. 2, the sealing body 3 is fitted with an opening of an outer can (battery container) 2 in which a power generating element (electrode group) is inserted, an electrolytic solution is injected, and a spacer 18 is placed. Then, the entire periphery of the sealing is laser-welded to form a sealed structure, and the sealed storage battery 1 is formed. The spacer 18
The material is not particularly limited as long as it functions as a spacer, and examples of the material include a nylon resin.

[0018]

EXAMPLES The present invention will now be described more specifically with reference to examples, but the present invention is not limited thereto.

Example 1 Assuming that the length from the center of the hole 17d to the bent line A is 1 as shown in FIG.
7d The length from the center to the end B is 0.8 (representing the lead piece size ratio of 0.8: 1)｝, using nickel-plated soft iron hollow rivets, nylon gaskets, and nickel plating. Steel plate sealing plate, nylon insulating plate,
The nickel rivet was assembled, inverted, and the lower end of the hollow rivet was expanded with a punch. Next, the positive electrode terminal cap with the valve element incorporated inside is placed on the head of the hollow rivet, the negative electrode rod is brought into contact with the open rivet under pressure, and the cap head is connected to the positive electrode to apply voltage. ,
The sealing projection was manufactured by welding the projection for welding on the back surface of the positive electrode terminal cap. Using the manufactured sealing body, insert the electrode plate group into a nickel-plated steel sheet outer can, inject an electrolytic solution, place a spacer, and then fit the sealing body to the upper open end of the outer can. Then, the entire periphery was laser-welded to form a sealed structure, and a storage battery was manufactured. Table 1 shows the number of stoppages of the assembly line and the number of flows per minute when manufacturing 1,000 storage batteries. FIG. 6 shows the results of measuring the welding strength of the positive electrode terminal cap of the manufactured storage battery for every 10,000 shots.

Example 2 As in Example 1, when the length from the center of the lead piece 17d to the bent line A from the center of the hole 17d is 1, the length from the center of the hole 17d to the end B is 0.5 (lead piece dimensional ratio). (Represented as 0.5: 1) was used to produce a storage battery. Table 1 shows the number of stoppages of the assembly line and the number of flows per minute when manufacturing 1,000 storage batteries.

COMPARATIVE EXAMPLE 1 Assuming that the length from the center of the lead piece 17d to the bent line A shown in FIG. 3 is 1, the length from the center of the hole 17d to the end B is 0.1.
4 (represented by a lead piece size ratio of 0.4: 1), and a storage battery was manufactured in the same manner as in Example 1. 1,000
Table 1 shows the number of stoppages of the assembly line and the number of flows per minute in the production of individual storage batteries. FIG. 6 shows the results of measuring the welding strength of the positive electrode terminal cap of the manufactured storage battery for every 10,000 shots. Comparative Example 2 Similarly to Comparative Example 1, when the length from the center of the lead piece ｛hole 17d to the bent line A is 1, the length from the center of the hole 17d to the end B is 0.36 (the lead piece dimensional ratio 0.36 The battery was manufactured using を. Table 1 shows the number of stoppages of the assembly line and the number of flows per minute when manufacturing 1,000 storage batteries.

[0022]

[Table 1]

As shown in Table 1, in the production of a storage battery having a lead piece within the scope of the present invention in Examples 1 and 2, the number of line stops was 0 and the number of flows per minute The production method of the storage battery of the present invention is much higher in productivity than the conventional method because the flow rate of the parts feeder is about twice that of the comparative example using the product. Further, as shown in FIG. 6, in the manufacture of the storage battery having the lead piece which is within the scope of the present invention of the first embodiment, even after 60,000 shots, the tip of the electrode rod has little wear and the welding strength of the positive electrode terminal cap is low. Although stable, in the production of the storage battery having the lead piece of the conventional product of Comparative Example 1, the tip of the electrode rod was partially reduced from about 30,000 shots, and the welding strength was reduced as the number of shots increased.

As a welding strength test method (compression test), a battery is clamped and fixed to a clamp,
Load cell speed 1 using a stainless steel load cell
A load was applied to the positive electrode terminal cap at the top of the battery at 00 mm / min, and the welding strength was measured. The number of samples per data was 1,000. As the number of times of assembly line stoppage and the number of flows, 1,000 storage batteries were manufactured, and the number of times of assembly line stoppage and the number of lines flowing for one minute in the production assembly line were measured.

[0025]

According to the present invention, there is provided a sealed storage battery, particularly a sealed storage battery having a sealing body in which a hollow rivet is attached to a sealing plate via a lead piece connected to a positive electrode current collector, an insulating plate and a gasket. The shape of the lead piece is characteristic.In the production of sealed storage batteries, when the rivet lower end is expanded and caulked and fixed to the sealing plate together with the lead piece and the insulating plate, the rivet lower end does not expand unevenly, A sealed storage battery in which the plate does not deform can be obtained. The resulting sealed storage battery can be manufactured with high productivity, has excellent airtightness and liquid leakage resistance, and has high reliability.

[Brief description of the drawings]

FIG. 1 is a schematic view of a small rectangular sealed storage battery.

FIG. 2 is a sectional view of the sealed storage battery according to the present invention taken along line II of FIG. 1;
It is sectional drawing of the sealing body part along a line.

FIG. 3 is a schematic view of an example of a lead piece of the present invention.

FIG. 4 shows the sealed storage battery of FIG.
It is sectional drawing of the sealing body part along the line | wire corresponding to I line.

5 is a cross-sectional view of the sealing body along a line corresponding to the line II in FIG. 1 of the sealed storage battery when the positive electrode terminal cap is welded to the hollow rivet.

FIG. 6 is a graph showing the relationship between the welding strength of the positive electrode terminal cap of the storage battery and the number of times of welding.

FIG. 7 is an exploded perspective view of a sealing body of a conventional sealed storage battery.

FIG. 8 is a schematic view of a conventional lead piece.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sealed storage battery 2 Outer can (battery container) 3 Sealing body 11 Positive electrode terminal cap 11a Notch part 11b Welding projection part 11c Flange 12 Valve body 13 Hollow rivet 13a Hollow rivet head 13b Hollow rivet Hollow shaft 13c Hollow rivet lower end 13d Hollow rivet hole 14 Gasket 14a Flange 14b Gasket cylinder 15 Seal plate 15b Seal plate recess 15d Seal plate hole 16 Insulating plate 16d Insulating plate hole 17 Lead piece 17d Lead piece hole 18 Spacer 21 Punch 22 Base 23 Negative electrode rod 24 Positive electrode 25 jig

Claims (1)

[Claims] 1. A positive electrode terminal is welded to the head of a hollow rivet having a head and a hollow shaft integrally formed with the head, and the hollow rivet is swaged at the tip of the hollow shaft.
In a sealed storage battery including a lead piece connected to a positive electrode current collector, a sealing body attached to a sealing plate via an insulating plate and a gasket, the lead piece has two surfaces formed by bending a thin plate. One surface is provided with a hole through which the hollow rivet is inserted, and the other surface is connected to the current collector. The length from the center of the hole to the bent line in the longitudinal direction of the surface having the hole is determined. A sealed storage battery characterized in that the length from the center of the hole to the opposite end is 0.5 to 1 when 1 is set.