JPH0311803Y2 - - Google Patents

Description

[Detailed explanation of the idea]

INDUSTRIAL APPLICATION FIELD The present invention relates to a sealed alkaline storage battery that uses nickel oxide as a positive electrode active material and cadmium, zinc, iron, or the like as a negative electrode active material, and particularly relates to the structure of the positive electrode terminal portion. BACKGROUND ART Sealed alkaline storage batteries have high reliability and excellent charging and discharging characteristics, and their demand is increasing rapidly as electrical equipment becomes smaller and more portable. On the other hand, in recent years, electrical equipment has become significantly more compact and thin due to the development of electronic components, and as a result, batteries, which serve as power sources, are also required to be high capacity, small, and thin. However, the currently widely used sealed alkaline storage batteries are of a cylindrical type, but in the case of this cylindrical type, the cross section is circular, so there are problems such as a lot of wasted space for storing batteries in electrical equipment. be. Moreover, in the case of a cylindrical type, there are certain technical and performance limits to making the battery thinner, and it has been difficult to obtain an extremely thin battery. Under these circumstances, there has been a strong desire for the emergence of a small, rectangular sealed alkaline storage battery. However, when converting a sealed alkaline storage battery into a rectangular shape, it is necessary to secure the lid, which has a positive terminal that also serves as a safety valve, to the opening of the battery container through packing, as is generally used in sealed cylindrical alkaline storage batteries. Needless to say, it is difficult to adopt such a structure from a technical standpoint as well as from the standpoint of leakage resistance. For this reason, it has conventionally been proposed to manufacture a sealed prismatic alkaline storage battery by welding a lid equipped with a positive terminal as shown in FIG. 2 to the opening of the battery container.
In FIG. 2, reference numeral 1 denotes a metal lid, and a hole is provided in the center for attaching packing 2 and a hollow rivet to be described later. Packing 2
is made of plastic or rubber with a sealant applied to its surface to maintain electrical insulation and electrolyte leakage resistance. 3 is a hollow rivet, made of, for example, nickel-plated iron,
It is fixed to the lid 1 by caulking the tip 3'' of the hollow shaft 3' through a packing 2 and a metal washer 4. 5 is a terminal cap having a flange of the same shape as the head of the hollow rivet 3. It is fixed to the head of the hollow rivet 3 by spot welding. 6 is a rubber valve body, which is placed inside the terminal cap 5 so as to close the hole of the hollow rivet 3. 7 is a power generation valve body. The positive electrode lead of the element is connected to a metal washer 4.The lid 1 is fitted into the opening of a metal battery container and fixed by laser welding to seal the battery container. The problems that Sealed Square Alkaline Storage Batteries are intended to solve are those that are directly attached to electrical equipment and used for long periods of time while being repeatedly charged and discharged. Since the battery is used in many applications, leakage resistance is an important issue.A sealed rectangular alkaline storage battery with a positive terminal of the structure shown in Figure 2 is airtight by caulking hollow rivets. However, maintaining airtightness by caulking alone was still insufficient in terms of leakage resistance and long-term reliability. The present invention provides a sealed rectangular alkaline storage battery that solves the problem, and includes a terminal cap fixed to the head of a hollow rivet, and a valve body disposed within the terminal cap so as to close the hole of the hollow rivet. A structure in which the positive electrode terminal of the structure is fixed to the lid via packing by caulking the tip of the hollow shaft of the hollow rivet, and the hollow shaft of the hollow rivet is expanded in the outer circumferential direction and pressed against the packing. Function As shown in Fig. 2, the conventional positive electrode terminal part is made by passing a hollow rivet 3 through a packing 2 into a hole provided in a lid 1 which is a part of the battery container. The distal end 3'' of the hollow shaft 3' is fixed by caulking, and the lid is pressed vertically by the caulking to maintain airtightness. In the present invention, by improving the caulking conditions, the tip 3'' of the hollow shaft 3' of the hollow rivet 3 is caulked, and the hollow shaft 3'
is inflated toward the outer periphery and pressed against packing 2. This improves the airtightness at the contact surfaces of the hollow shaft 3' of the hollow rivet 3, the packing 2, and the inner wall of the hole in the lid 1, and provides excellent leakage resistance in addition to the conventional airtightness achieved by pressure from above and below. It became possible to obtain liquid properties. Embodiment FIG. 1 shows an embodiment of the positive terminal part of a sealed prismatic alkaline storage battery according to the present invention. In the figure, the same reference numerals as in FIG. 2 indicate the same working members. This embodiment has almost the same structure as the conventional example shown in FIG.
A hollow rivet 3 is passed through a hole made in a metal lid 1 through a packing 2 whose surface is coated with a sealant, and the tip 3' of the hollow shaft 3'' of the hollow rivet 3 is caulked, and at the same time the hollow shaft 3' The hollow shaft 3' is inflated in the outer circumferential direction and pressed against the packing 2.A method for simultaneously achieving caulking of the hollow shaft 3' and expansion in the outer circumferential direction is to appropriately select the shape of the caulking punch and the pressure application method during caulking. This can be done by The lid 1 is sealed by laser welding a lid 1 having a positive electrode terminal 9 shown in FIG. Type alkaline storage battery and second
A plurality of conventional sealed rectangular alkaline storage batteries each having a positive electrode terminal having the structure shown in the figure were manufactured, and the electrolyte leakage resistance of these batteries was investigated. The results are shown in the following table. Test conditions are temperature 45℃, humidity 90~
The test was carried out at a constant temperature of 95% by applying red litmus paper around the seal part of Lid 1 every 15 days to check for leakage.

[Table] As is clear from the table, it can be confirmed that the leakage rate of the sealed prismatic alkaline storage battery according to the present invention is significantly lower than that of conventional products. The reason for this difference is
In the sealed rectangular alkaline storage battery according to the present invention, the hollow shaft 3' of the hollow rivet 3 is caulked at the tip 3'' and swells toward the outer circumference.
The adhesion to the packing has been significantly improved, and as a result, the leakage resistance of the electrolyte has been improved.
On the other hand, conventional sealed rectangular alkaline storage batteries are inferior in leakage resistance because the tip 3'' of the hollow shaft 3' of the hollow rivet 3 is only caulked, and there is no pressure in the outer circumferential direction by the hollow shaft 3'. Effects of the Invention As described above, according to the present invention, it is possible to enhance the reliability of the seal portion of a sealed alkaline storage battery and improve the leakage resistance of the electrolyte.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of the positive terminal part of a sealed prismatic alkaline storage battery according to the present invention, FIG. 2 is a sectional view showing an example of the positive terminal part of a conventional sealed prismatic alkaline storage battery, and FIG. 1 is an external view showing an example of the external appearance of a sealed prismatic alkaline storage battery according to the present invention. 1... Lid, 2... Packing, 3... Hollow rivet, 3'... Hollow shaft of hollow rivet, 3''...
Tip of hollow shaft of hollow rivet, 4... Metal washer, 5... Terminal cap, 6... Valve body, 7
...Positive electrode lead, 8...Battery container, 9...Positive electrode terminal.

Claims (1)

[Claims for Utility Model Registration] A sealed alkaline storage battery comprising a hollow rivet 3 having a terminal cap 5 formed on its head and packing 2, wherein the hollow rivet 3 is attached to the lid 1 through the packing 2. A sealed alkaline storage battery characterized in that the hollow shaft 3' of the hollow rivet bulges outward and presses the packing 2.