JPH05190160A - Sealed battery - Google Patents

Abstract

PURPOSE:To provide a sealed battery having high reliability by improving the heat resistance of a gasket as the constitution member of a sealed battery having a welded part and improving the electrolyte preventing faculty. CONSTITUTION:A sealed battery is equipped with a metal case into which positive and negative electrode plates and an electrolytic solution are accommodated, gasket 1 nipped by a hollow rivet 34 at the upper opened port part of the metal case, and a terminal 31 welded on the hollow rivet 34, and the upper edge gasket 1 is a gasket made of nylon 46 in the dried state where the water content is regulated to 2% or less before assembling a battery.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a sealed battery.

[0002]

2. Description of the Related Art In recent years, with the progress of electronics, many types of batteries have been produced as main power sources and backup power sources for various electronic devices, and in particular, small sealed batteries have been widely used.

Among small sealed batteries, there are known prismatic, cylindrical and flat type batteries in which positive and negative electrodes are insulated and sealed using a synthetic resin. Examples of these conventional ones will be described below with reference to the drawings.

In FIG. 3, reference numeral 31 is a cap-shaped terminal provided on a metallic lid plate 33 that seals the upper edge of a rectangular bottomed metallic case 32 that houses battery elements. The peripheral portion of the metal lid plate 33 is welded to the upper edge 32a of the opening of the rectangular bottomed metal case 32 by laser beam welding to seal the rectangular bottomed metal case 32. It is a thing. The enlarged flange portion 31a at the lower end of the cap-shaped terminal 31 is spot-welded to the upper edge portion 34a of the hollow rivet 34. The hollow rivet 34 has an elastic valve element 3 made of synthetic rubber in a space formed by the upper edge portion 34a and the cap-shaped terminal 31.
5 is stored under pressure, the lower end portion 34c at the lower end of the central through hole 34b is enlarged outwardly, so-called caulking is performed with the upper edge portion 34a, and a metal-made gasket 36 made of synthetic resin is used. The cover plate 33 and the washer 37 are held together. The lower end of the washer 37 is bent downward and spot-welded to the positive electrode lead of the battery element. That is, the cap-shaped terminal 31, the hollow rivet 34, and the washer 37 are positive electrodes, and the bottomed metal case 32 and the metal lid plate 33 are negative electrodes.

As shown in FIG. 4, the conventional small cylindrical sealed battery has a cylindrical case 42 accommodating the battery element 41, and the upper edge 42a of the opening is curled toward the center to form a gasket / cover member 43 made of synthetic resin. It is crimped and sealed. A hollow rivet 44 is fitted in the central through hole of the gasket / cover material 43, and an upper edge portion 44a thereof is spot-welded to an enlarged flange portion 45a below the cap terminal 45. The hollow rivet 44 accommodates the elastic valve element 46 made of synthetic rubber under pressure in the space formed by the upper edge portion 44a and the cap-shaped terminal 45, and the lower end portion 44c at the lower end of the central through hole 44b. The washer 47 is attached to the gasket / cover material 43 by expanding outward and so-called caulking with the upper edge portion 44a. Reference numeral 48 denotes a positive electrode reed plate spot-welded to the lower end portion 44c of the hollow rivet 44. That is, the hollow rivet 44, the cap-shaped terminal 45, and the washer 47 serve as a positive electrode, and the cylindrical case 42 serves as a negative electrode.

The above-mentioned small prismatic type battery shown in FIG. 3 and cylindrical type shown in FIG. 4 are both made of a synthetic resin gasket 3.
6. The positive electrode and the negative electrode are insulated by the gasket / cover material 43, and further, the outflow of the electrolytic solution and the like inside the battery is prevented, and the sealed state is maintained. The materials of the gasket 36 and the gasket / cover material 43 are KOH, NaOH, LiOH, which are often used as an electrolytic solution for small sealed batteries.
Polyamide-based materials having high alkali resistance to alkaline electrolytes such as Nylon 66 are generally used.

However, welding processing such as laser beam welding and spot welding is performed in the vicinity of the gasket 36 and the gasket / cover material 43, and in particular, the heat generated by the metal lid plate 33 due to laser beam welding is 1
The temperature ranges from 00 ° C. to 200 ° C. and reaches several hundred degrees in the vicinity of the opening upper edge portion 32a. Therefore, the melting point is 260 ° C,
The heat distortion temperature of 70 ° C exceeded the heat resistance limit of nylon 66, and there was a tendency for the alkaline electrolyte sealing ability to decrease.

[0008]

The problem with the conventional sealed battery using nylon 66 for the gasket is that the gasket has a low melting point of 260 ° C. and a heat distortion temperature of 70 ° C. Part, the laser beam applied to the sealing part, the high heat generation temperature during welding processing such as spot welding exceeds the heat resistance limit of the nylon 66 gasket, and the ability to seal the alkaline electrolyte decreases, including the life. Moreover, the long-term reliability was low. And in the case of a small sealed battery and a thin prismatic type, AAA type or AAA type
In the case of a thin cylindrical shape such as a shape, since the welded portion and the gasket made of nylon 66 are extremely close to each other, the performance of the gasket is significantly deteriorated due to the heat. The present invention aims to solve such conventional problems.

[0009]

In order to solve the above-mentioned problems, the sealed battery of the present invention comprises a metal case accommodating a positive and negative electrode plate with a separator and an electrolytic solution, and an upper opening of the metal case. The gasket includes a gasket that is held by a hollow rivet and a terminal that is welded to the hollow rivet. The gasket is a dry nylon 46 gasket before the battery is assembled.
And the dry state of the nylon 46 gasket is
The water content is regulated to 2% or less.

[0010]

In a thin prismatic battery and a relatively small sealed battery such as AAA or AAA, the thermal effect of welding processing such as laser beam welding and spot welding on the gasket is inevitably large. Absent.

According to the present invention, nylon 46 having a melting point of 290 ° C. and a heat distortion temperature of 230 ° C. is adopted as the gasket material according to the above construction, so that heat resistance higher than heat generated by welding processing such as laser beam welding or spot welding is performed. It has a limit to prevent the deterioration of the alkaline electrolyte sealing ability.

Since the water absorption of nylon 46 is higher than that of nylon 66, which is a material for conventional gaskets, and it is put in a dry state with a water content of 2% or less, it is made of nylon 46. The gasket of (1) absorbs and swells the electrolytic solution to seal the battery. As long as the cork stopper absorbs water and swells, the clinging effect to the components is improved so as to prevent the wine from leaking, and as a result, the alkaline electrolyte sealing ability is improved and the long-term reliability is improved.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

In the embodiment of the present invention, the same components as those in the conventional example are designated by the same reference numerals as those in FIGS. 3 and 4 and their description is omitted.

(Embodiment 1) In FIG. 1, reference numeral 1 denotes a nylon 46 gasket whose water content is restricted to 2% at the time of clinging, and a metal lid plate 33 is provided by caulking a hollow rivet 34. The point where the washer 37 and the cover plate 33 are fixed to the upper edge portion 34a of the hollow rivet is the same as that of the conventional example shown in FIG.

Table 1 shows the results obtained by using nylon 46 according to Example 1 of the present invention as a gasket material for a prismatic small sealed battery and a comparative example in which nylon 46 previously absorbed to 3% was used. , Using nylon 66 according to the conventional example, melting point of 260 ° C., heat distortion temperature of 250
100 ° C. in a glass reinforced conventional example of nylon 66 having a melting point of 320 ° C. and nylon 6T having a melting point of 320 ° C. and a heat deformation temperature of 130 ° C. at 60 ° C. and 90% humidity atmosphere. The results of a leak test after storage for one month are shown.

[0017]

[Table 1]

As is clear from (Table 1), the prismatic small closed battery according to Example 1 of the present invention has no leakage after storage. However, in the case of the comparative example in which water was absorbed by 3% in advance and clinging to it, there was no improvement in the clinging effect due to water absorption of the electrolytic solution, and 3% leakage occurred.

In the conventional example, 25% of the leaked product was generated, but this is because of the reason described above. Further, in the conventional example of glass reinforced nylon 66 having a higher heat resistant temperature, 45% liquid leakage occurred. this is,
This is because the mixed glass fibers are dissolved in the alkaline electrolyte. Furthermore, in the case of using nylon 6T,
35% of leaked products occurred. This is because the molding strain remains at the time of molding due to its high melting point, and the internal residual strain is alleviated by the heat generated by the welding process such as laser beam welding and spot welding, which causes deformation and the alkaline electrolyte sealing ability is reduced. is there. Another major reason is that the water absorption rate is lower than that of nylon 66 and there is almost no swelling due to water absorption by the electrolytic solution.

(Embodiment 2) In FIG. 2, reference numeral 21 is a gasket / cover material made of nylon 46, the water content of which is regulated to 2% or less when the battery is hermetically assembled. This is similar to the conventional example shown in FIG. In Example 2 of the present invention, the spot welding process of the gasket / cover material 21 has almost no heat effect, and the electrolyte sealing performance is improved by the water absorption expansion by the electrolyte.

[0021]

As described above in detail, according to the present invention,
By increasing the heat-resistant temperature of the gasket, the thermal effect of welding processing such as laser beam welding and spot welding is reduced. In addition, since it sticks in a dry state of 2% or less, the gasket absorbs a large amount of water and swells with the electrolytic solution, so that the effect of sticking to each component is improved, and as a result, the electrolytic solution sealing ability is improved. Therefore, it becomes possible to provide a small sealed battery having a longer life and higher reliability.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a terminal portion of a prismatic small sealed battery according to a first embodiment of the present invention.

FIG. 2 is a partially cutaway side view showing a main part of a cylindrical small sealed battery according to a second embodiment of the present invention in section.

FIG. 3A is a perspective view showing an appearance of a conventional small rectangular sealed battery, and FIG. 3B is an enlarged cross-sectional view of the same main portion.

FIG. 4 is a partially cutaway side view showing a main part of a conventional cylindrical small sealed battery in a cross section.

[Explanation of symbols]

 1 Nylon 46 gasket 21 Nylon 46 gasket and cover material 31 Cap terminal 31a Enlarged flange 32 Square bottomed metal case 32a Opening upper edge 33 Lid plate 34, 44 Hollow rivet 35, 46 Elastic valve Body 37, 47 Washer 42 Cylindrical case

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takafumi Fujii 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. A metal case containing a positive and negative electrode plate having a separator interposed therein and an electrolytic solution, a gasket held by a hollow rivet at an upper opening of the metal case, and a terminal welded to the hollow rivet. The sealed gasket is a gasket made of nylon 46 in a dry state before the battery is assembled. 2. A metal case containing a positive and negative electrode plate and an electrolytic solution with a separator interposed therebetween, a metal cover plate to be laser-beam welded to the upper edge of the opening of the metal case, and the metal cover plate. In a sealed battery having a hollow rivet inserted into a through hole and holding a gasket with a cover plate, and a cap-shaped terminal welded to the upper edge of the hollow rivet, the gasket contains before the battery is assembled. A sealed battery using a dry nylon 46 gasket with a water content regulated to 2% or less. 3. A metal case containing a positive and negative electrode plate and an electrolytic solution with a separator interposed therebetween, a gasket / cover material having a peripheral edge fixed to the upper part of the metal case, and a through hole of the gasket / cover material, And in a sealed battery having a hollow rivet for holding the gasket / cover material and a cap-shaped terminal welded to the upper edge of the hollow rivet, the gasket / cover material has a A sealed battery with a nylon 46 gasket and cover material in a dry state regulated to 2% or less.