JPH0656759B2 - Method for manufacturing sealed lead acid battery - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a sealed lead-acid battery, and more particularly to a method for forming a battery case and a safety valve suitable for making the battery lightweight and thin.

2. Description of the Related Art A technique for forming a battery case and a safety valve from a sheet-shaped synthetic resin body is already described in JP-A-59-207558.
The electrode plate group and the electrode pole part, which is the electricity extraction part, are sandwiched by two resin sheets, and the electrode pole part is exposed outside between both sheets, and both sheets are partly arranged along the electrode plate group periphery. A method is known in which a battery case is formed by heat welding leaving an unwelded portion and using the unwelded portion as a safety valve.

Problems to be Solved by the Invention However, the above technique does not recognize the problem of the electrolytic solution brazing liquid from the boundary between the pole column and the battery case due to the poor adhesion between the pole column and the battery case.

Generally, when resin sheets are heat-sealed with a metal plate partially sandwiched between them, heat loss is large at the metal plate portion because the metal is a good conductor of heat, and the temperature rise of the resin sheet causes Due to insufficient fusion, the cross-sectional shape of the metal plate varies industrially, and it is difficult to always accurately match the cross-sectional shape of the heat welding jig, resulting in non-uniform crimping force. There is a phenomenon in which the non-welded portion is likely to remain at the boundary between the resin sheet and. The same problem is feared in the above-mentioned conventional technique.

An object of the present invention is to solve the above problems and to provide a method for manufacturing a sealed lead-acid battery which is excellent in brazing liquid resistance of an electrolytic solution and which is easy to form a safety valve and inject the electrolytic solution. .

Means for Solving the Problems The above-mentioned object is to make a positive electrode plate, a negative electrode plate and a pole plate, and a pole plate group consisting of a separator into a flexible sheet-shaped synthetic resin body together with a plate-shaped synthetic resin body. All parts including parts are sealed and housed, and the lead wire or terminal for electricity extraction is connected to the pole post through the through hole provided in the battery case part in contact with the pole post, and then the through hole is sealed, This is achieved by providing a notch portion that penetrates the inside of the battery container portion in contact with the synthetic resin body that also serves as an inlet for the electrolytic solution and an outlet for the generated gas, that is, a safety valve.

Since all the electrode plates including the poles are stored in the battery case, the battery case can be sealed only by bonding the resin sheets to each other. The bonding work with the bonding device is simple, the reliability of the bonding part is high, and the brazing liquid of the electrolytic solution does not occur. Since the electricity take-out part is provided through the through hole provided in the battery case after the battery case is formed, there is no restriction on the shape of the pole part, and the terminal part can be installed within the battery thickness, and the battery volume efficiency is improved. Is improved. As for the sealing of the through-hole, the molten synthetic rubber material can be well wetted with the metal and the resin material only by dropping or injecting the molten synthetic rubber material into the hole portion, and the sealing can be performed easily and surely, and the brazing solution of the electrolytic solution does not occur. The plate-shaped synthetic resin plate keeps the flatness around the cut portion to stabilize the operation of the safety valve, and when the cut portion that also serves as the electrolyte inlet and the safety valve is provided in the battery case, Acts as a protective plate to prevent the notches from reaching the battery case. At the interface between the resin plate and the battery case, a very thin water film is formed by the water introduced from the electrolytic solution, which exhibits a packing action and a sizing action and maintains good airtightness regardless of the posture of the battery. When the internal pressure of the battery becomes higher than the external atmospheric pressure due to overcharging of the battery, the battery case operates in a swelling direction, so that the interface between the resin plate and the battery case is separated and gas is released through the cut portion. After releasing the gas, the resilience due to the flexibility of the battery case allows the resin plate to be adhered to the original resin to maintain airtightness, thereby reliably operating as a safety valve. In addition, the presence of this resin plate makes it easier to flip the resin sheet of the battery case when inserting the electrolyte injection tube into the battery through the notch, and also makes the injection tube slip better, so that the electrolyte injection work And productivity is improved.

Examples of the present invention will be described below.

Example 1 In FIG. 1, the positive electrode plate and negative electrode plate (vertical 8
5 mm x width 45 mm x thickness 1.5 mm) and a plate group 1 consisting of one glass mat separator each and one 0.5 mm thick
The ABS resin flat plate 2 is sandwiched between two resin sheets 3 made of a composite of polypropylene and vinylidene chloride having a thickness of 0.1 mm, which has acid resistance, heat-welding property and flexibility, and the width is set along the periphery of the electrode plate group. A battery case made of a resin sheet having a thickness of 2 mm and heat-sealed with a heat press machine and sealed with the heat-welded portion 4 was formed. At this point, the electrode plate group including the electrode columns 5 is completely sealed in the battery case. Then, a punch-like cutter is used to make a through hole 6 in a part of the resin sheet on one side of the portion in contact with the pole portion provided on the positive electrode plate and the negative electrode plate, and a 0.75 mm diameter wire 7 is formed as a lead wire 7 for extracting electricity through this portion. The copper wire was connected to the pole portion by soldering. Then, a molten material of the sealing body 8 made of synthetic rubber having good adhesion to metal and resin was dropped into the hole portion and solidified to seal the through hole portion. Next, a cut 9 is formed in a portion of the resin sheet on one side of the portion in contact with the ABS resin plate, which is penetrated by a sharp blade, and an injection pipe for the electrolytic solution is inserted from this portion, and diluted sulfuric acid having a specific gravity of 1.32 is added at 20 ° C. A predetermined amount was injected, and this was absorbed and held by the separator and the electrode plate. When the injection tube is pulled out after the electrolyte is injected, the resilience of the resin sheet causes the resilience of the resin sheet to cause the resin sheet around the notch to adhere well to the resin plate, and the water produced by the electrolyte causes the resin sheet to interface with the resin sheet. A water film was formed. This water film is extremely thin and exhibits a packing action and a gluing action, prevents outside air from entering the battery case and, at the same time, does not peel off by its own weight even if the battery is held in any posture, which is a good result. It exhibited adhesion.

A cycle life test of charge and discharge was carried out using the above sealed lead acid battery, and good results were obtained with an average life of 150 cycles or more. Even if the posture of holding the battery was changed in various ways, there was no difference in the above performance, indicating that the airtightness of the cut portion was good. When the pressure was increased due to overcharging, the notch was opened and acted effectively as a safety valve, and when depressurized, good airtightness was maintained.

Incidentally, it is preferable that the resin sheet material of the battery case body is made thinner so that the adhesiveness with the resin plate at the cut portion can be improved, but if it is made thin, the phenomenon of moisture permeation and oxygen permeation through the resin sheet becomes remarkable, Battery life becomes short due to electrolyte depletion and abnormal electrode plate oxidation. In such a case, it is clear that if resin materials with excellent moisture and oxygen permeation resistance are selected and these are used as a laminated sheet, the life will be greatly extended even with the same thickness. A resin sheet prepared by laminating and vinylidene chloride was used.

According to this example, both the heat-welded portion and the sealing portion of the through hole showed good airtightness, and the brazing solution of the electrolytic solution could be prevented. Further, a safety valve having good performance could be easily formed, and the injection of the electrolytic solution could be performed easily.

Example 2 The basic structure of the battery was the same as that of Example 1, and the connection between the pole portion and the lead wire for extracting electricity and the periphery thereof were covered with an epoxy resin having good adhesion to metal and good acid resistance. After that, the through hole was sealed with synthetic rubber. As a result, the phenomenon of electrolytic solution rising from the interface between the conducting wire and the synthetic rubber, which was occasionally recognized at the end of the charge / discharge cycle test without the resin coating, was eliminated, and the reliability of the sealing of the through hole was improved. .

Example 3 The basic structure of the battery was the same as in Example 1, and after sealing the through hole with synthetic rubber, the surface of the synthetic rubber was coated with epoxy resin. As a result, synthetic rubber is flexible and sticky due to its characteristics, so if the lead wire or terminal for electrical extraction moves slightly while handling the battery, you may feel uneasy about safety or touch the sealing part with your hand. There was a discomfort like sticking, which was not desirable in terms of commercial value as a battery, but the sealing of the epoxy resin can strengthen the sealing part, eliminating the anxiety and discomfort during handling. We were able to.

Example 4 The basic structure of the battery is the same as in Example 1, and the resin plate 2 and the resin sheet of the battery case body in the portion in contact with the resin plate 2 are heat-welded to each other so as to surround the notch 9 as shown in FIG. Then, the safety valve heat-welded portion 10 was formed. As a result, the adhesion between the resin plate and the resin sheet in contact with the resin plate is increased because the resin sheet around the cut portion becomes stronger, preventing outside air from entering the battery and increasing the internal pressure in the battery. It was possible to improve the reliability of the battery by making the working pressure constant when exhausting gas from the cut portion.

Example 5 A notch 9 portion, which is a safety valve, was covered with a neutralizing material for an electrolytic solution consisting of a resin mat impregnated with sodium carbonate so as to cover the notch 9, and this was covered with a resin sheet to partially surround the periphery. It was fixed to the resin sheet of the battery case by heat welding leaving the welded portion. As a result, a small amount of sulfuric acid mist discharged during gas exhaust from the cut portion is absorbed and neutralized by the neutralizing material portion, and the gas discharged from the unwelded portion does not contain a sulfuric acid content, and thus the battery of the present invention is used. Contamination of the equipment used by sulfuric acid,
It was possible to prevent it from corrosion.

Example 6 The electrode plate group was placed in a thin resin pipe having heat shrinkability, heated to shrink the resin pipe, and a compression force was applied between the surfaces of the electrode plate group to produce the battery. As a result,
The air bubbles generated during discharge usually weaken the adhesion between the plates, which reduces the capacity especially during high rate discharge.However, by applying a compressive force between the plates by the above method, the battery discharge The capacity could be improved.

EFFECTS OF THE INVENTION According to the present invention, it is possible to improve the sealing property of the heat-welded portion and the electricity extraction portion of the battery case, so that the brazing liquid resistance of the electrolytic solution is excellent. It is possible to obtain a sealed lead acid battery.

[Brief description of drawings]

FIG. 1 is a perspective view of a sealed lead-acid battery according to one embodiment of the present invention, and FIG. 2 is an enlarged view of a main part of another embodiment. 1: electrode plate group, 2: resin plate, 3: resin sheet, 4: heat-welded portion, 6: through hole, 7: conductor wire, 8: sealing body, 9: notch

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kensuke Hironaka 2-1-1, Nishishinjuku, Shinjuku-ku, Tokyo Inside Shin-Kindo Electric Co., Ltd. (72) Yasuhisa Wada 2-1-1, Nishishinjuku, Shinjuku-ku, Tokyo No. 1 in Shinjin Todenki Co., Ltd. (72) Inventor Asahi Miura 2-1-1 Nishishinjuku, Shinjuku-ku, Tokyo Shinjin Todenki Co., Ltd. (72) Inventor Hayakawa et al. 2-1-1, Nishishinjuku, Shinjuku-ku, Tokyo (72) Inventor Akio Komaki 2-1-1, Nishishinjuku, Shinjuku-ku, Tokyo Shinjin-to Electric Co., Ltd. Sadao Kinashi (56 ) References Japanese Patent Laid-Open No. 59-71254 (JP, A) Shoukai 60-189954 (JP, U)

Claims (1)

[Claims] 1. An electrode group consisting of a positive electrode plate, a negative electrode plate, a pole and a separator is hermetically housed in a battery case body made of a sheet-shaped synthetic resin body having flexibility together with a plate-shaped synthetic resin body. Then, after connecting a lead wire or a terminal through a through hole provided in the battery case body that abuts against the pole portion, the through hole is sealed with a synthetic rubber material and abuts against the plate-shaped synthetic resin body. A notched portion that penetrates a part of the battery case is provided, and the plate-shaped synthetic resin body and the notched part periphery of the battery case are fixed, leaving a part of the sealed lead-acid battery. Production method.