JPS6142375B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD This invention relates to a sealed alkaline battery, and in particular to improvements in the sealing portion thereof. Conventionally, as a sealed alkaline battery, as shown in FIG. , anode material 4
A structure is known in which a power generating element consisting of a cathode material 1, an anode material 4, a separator 6, etc. is sealed by bending the upper opening 5a of a metal can 5 loaded with the metal can 5 inward and pressing it. It is.
In this case, an annular gasket 3 as shown in FIG.
By bending the opening 5a of the metal can 5 inward, the gasket 3 is compressed to obtain a sealing force. However, in the conventional sealed alkaline battery as described above, when the opening 5a of the metal can 5 is bent inward, the gasket 3 is also bent inward, so that the gasket 3 is biased upward. As a result, the stress distribution in the gasket 3 is not uniform, and as a result, the force applied to the dish-shaped terminal 2 becomes large, which may cause deformation of the terminal 2. Because of this, with conventional sealed alkaline batteries as mentioned above, on the one hand there is a risk of leakage due to poor tightening, and on the other hand, there is a risk of deformation due to uneven tightening force, causing the battery to deform. There was a problem that spoiled the appearance. This invention was made to solve the above-mentioned problems, and its purpose is to make the stress distribution of the gasket uniform, thereby creating a more liquid-tight seal, and also improving the tightness. To provide a sealed alkaline battery which eliminates unbalanced biasing force, prevents deformation of terminals, improves leakage resistance, and prevents deterioration of appearance. As will become clear from the embodiments described later, the sealed alkaline battery according to the present invention includes an annular gasket arranged around the lower opening of the dish-shaped terminal loaded with one electrode material, in which the power generating element is hermetically sealed by bending inward and pressing the upper opening of the metal can loaded with the other polar material, wherein the gasket is connected to the upper opening of the metal can. The inner circumferential surface of the portion that is pressed between the peripheral edge of the dish-shaped terminal is an upright surface, and the outer circumferential surface of that portion is directed downward so that the wall thickness gradually expands from the upper end to the lower end. It is formed in advance into a tapered shape, and the taper angle is set between 2 degrees and 8 degrees. Hereinafter, the embodiment will be described in detail with reference to the drawings. FIG. 3 shows an embodiment of a sealed battery according to the present invention, in which an anode 10, a cathode 11 and Separator 12
It contains a power generation element consisting of: Here, the anode can 8 is made of, for example, iron plated with nickel, while the cathode terminal 7 is made of a clad material such as copper-stainless nickel. As shown in FIG. 3, the cathode terminal 7 has an outer edge 7a bent downward and folded back. Furthermore, an annular gasket 9 is fitted onto this outer edge 7a, and the outer periphery of this gasket 9 is covered with the opening 8a of the anode can 8. The opening 8a presses the gasket 9 by being bent inward. As a result, the gasket 9 is squeezed and compressed by the outer periphery of the opening 7b of the cathode terminal 7 and the inner periphery of the opening 8a of the anode can 8, and exerts a sealing force. However, at this time, the annular gasket 9
As shown in FIG. 4, the inner peripheral surface of the portion that is pinched by the opening 8a of the metal can 8 and the outer periphery of the opening 7b of the cathode terminal 7 is an upright surface, and The outer peripheral surface is formed into a tapered shape that gradually expands downward from the upper end to the lower end, so that the stress distribution of the gasket 9 changes from the upper end to the lower end. The tightening force becomes uniform toward the bottom, which eliminates uneven tightening force, preventing deformation of the terminal 7, and
Since a strong overall tightening force can be obtained, a more liquid-tight seal can be achieved. As a result, the appearance of the battery is not impaired, and leakage resistance is greatly improved. Here, the gasket 9 is made of a material such as polyethylene or polyamide resin, which is electrically insulating, highly elastic, and alkali-resistant. This gasket 9 is fitted in advance to the outer edge 7a of the cathode terminal 7 loaded with the cathode 11, although the details are omitted. The cathode terminal 7 fitted with the gasket 9 is inserted into an anode can 8, which has an anode 10 therein and a separator 12 placed thereon, from between the openings 8a of the anode can 8. At this time, the opening 8a of the anode can 8 is expanded outward in advance in order to facilitate fitting. In this way, gasket 9
is fitted onto the outer edge 7a of the cathode terminal 7 and inserted into the anode can 8, then the opening 8a of the anode can 8 is bent inward to seal the anode as shown in FIG. Obtain the structure alkaline battery. The table below shows the results of a comparative test of leakage resistance between the sealed alkaline battery configured as described above and a conventional sealed alkaline battery. The type of battery tested here is JISG13
Both types use potassium hydroxide (KOH) as the electrolyte. Test conditions are temperature 45
The experiment was carried out by storing at 95% humidity. Further, in this test, the gasket of the battery according to the present invention had a taper (angle θ) of 5 degrees, while the conventional gasket had no taper.

[Table] As is clear from the above table, the leakage resistance of the sealed alkaline battery according to the present invention is significantly improved compared to the conventional battery. FIG. 5 shows the taper angle θ of the gasket 9.
According to this figure, particularly excellent leakage resistance can be obtained when the taper angle θ is from 2 degrees to 8 degrees. As is clear from the description of the embodiments above, the sealed alkaline battery according to the present invention has an annular gasket arranged around the lower opening of the dish-shaped terminal loaded with one of the substances, and In a sealed alkaline battery in which a power generation element is hermetically sealed by bending inward and pressing the upper opening of a metal can loaded with the other electrode material, the annular gasket The inner circumferential surface of the portion pressed between the upper opening of the can and the periphery of the dish-shaped terminal is an upright surface, and the outer circumferential surface of that portion is approximately from the upper end to the lower end, with the wall thickness gradually decreasing as it goes downward. By setting this taper angle between 2 degrees and 8 degrees, the stress in the gasket is uniform and the tightening force is not biased. According to
Defects in appearance such as deformation of the terminal can be prevented, and leakage resistance can be greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a conventional sealed alkaline battery, FIG. 2 is a sectional view showing an example of a gasket used therein, and FIG. 3 is a sectional view showing an example of a sealed battery according to the present invention. 4 is a sectional view showing one embodiment of the gasket used in the present invention, and FIG. 5 is a sectional view showing the taper angle θ of the gasket.
It is a graph which shows the relationship between and the leakage occurrence state. 7... Cathode terminal, 8... Anode terminal, 9... Gasket, 10... Cathode, 11... Anode, 12...
Separator, θ...Taper angle.

Claims (1)

[Claims] 1. Place an annular gasket around the outer periphery of the lower opening of the dish-shaped terminal loaded with one polar material, and place the upper opening of the metal can loaded with the other polar material around the outer periphery of this gasket. In a sealed alkaline battery in which the power generation element is sealed by bending and pressing, the annular gasket is
The inner peripheral surface of the portion where the upper opening of the metal can is pressed between the peripheral edge of the dish-shaped terminal is an upright surface, and the outer peripheral surface of that portion has a wall thickness that is downward from approximately the top end to the bottom end. Therefore, a sealed alkaline battery is characterized in that it is preformed in a downwardly tapered shape so as to gradually expand, and the taper angle is set between 2 degrees and 8 degrees.