JPH0322853Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to the improvement of button-type batteries and aims to improve leakage resistance. In a button-type battery, an annular gasket made of synthetic resin such as polyethylene, polypropylene, or nylon and having an approximately L-shaped cross section is placed between the positive electrode can and the negative terminal plate, and this annular gasket is inserted into the opening of the positive electrode can. By tightening the peripheral wall inward, it is pressed against the peripheral edge of the negative electrode terminal plate to bring the contact surfaces between the opening peripheral wall of the positive electrode can, the annular gasket, and the peripheral edge of the negative electrode terminal plate into close contact with each other, and the electrolyte flows from these contact surfaces. to prevent leakage. By the way, the above-mentioned annular gasket is molded by injecting molten synthetic resin into the molding part (cavity) of a mold through a gate and cooling and solidifying it. Because it is easy to manufacture, the fifth
As shown in the figure, the annular gasket 1 is molded by a mold 10 having a gate 11 adjacent to the upper side of the rising portion 1a, so that when taken out from the mold, the upper portion of the rising portion 1a The resin 1c injected into the gate 11 of the mold 10 was attached to the side surface. The resin 1c injected into the gate of the mold was cut by lowering a knife (not shown) from above as indicated by the arrow in FIG. Therefore, as shown in FIG. 6, the rising portion 1a of the annular gasket 1
Resin 1c injected into the gate of the mold on the upper side of the
A portion of the annular gasket 1 remains and the outer peripheral surface of the rising portion 1a of the annular gasket 1 partially protrudes.
As shown in FIG. 8, a gap is created between the outer circumferential surface of the rising portion 1a of the annular gasket 1 and the inner circumferential surface of the positive electrode can 6, resulting in a decrease in sealing performance and a decrease in leakage resistance. As shown in the figure, not only the resin injected into the gate of the mold but also part of the outer periphery of the rising part 1a of the annular gasket 1 is cut off, reducing the thickness of the rising part 1a, resulting in poor sealing performance. There was a problem that the liquid leakage resistance deteriorated. In addition, in FIGS. 6 and 8, in order to make it easier to understand the resin 1c injected into the gate of the mold, the relationship between the resin 1c injected into the gate of the mold and the resin that originally constitutes the annular gasket 1 is shown. The boundary is indicated by a dashed line. This invention was made to solve the above problems, and when the annular gasket is molded with a metal mold, the resin injected into the gate of the mold,
The liquid leakage resistance is maintained at the outer circumferential end of the upper surface of the annular gasket and its rising portion, so that the drop in leakage resistance due to the partial protrusion of the outer circumferential surface of the rising portion or the decrease in the thickness of the rising portion as described above is maintained. It provides a button type battery that does not require a button type battery. That is, the present invention has a roughly L-shaped cross section consisting of an almost vertical rising part and a horizontal part, which is formed by injecting molten synthetic resin into the molding part of the mold through a gate, cooling it and solidifying it. An annular gasket is placed between the positive electrode can and the negative terminal plate, and by tightening the opening peripheral wall of the positive electrode can inward, the outer peripheral surface of the rising part of the annular gasket is brought into contact with the inner peripheral surface of the opening peripheral wall of the positive electrode can. In a button type battery in which the opening of the positive electrode can is sealed by pressing the inner circumferential surface of the rising part of the annular gasket against the peripheral edge of the negative electrode terminal plate, the annular gasket has the outer circumferential edge of the upper surface of the rising part. In this section, the resin injected into the gate of the mold is cut when the annular gasket is molded with a mold, and the upper surface of the rising part of the annular gasket is inside the opening peripheral wall of the positive electrode can. The present invention relates to a button type battery characterized in that the positive electrode can and the negative electrode terminal plate are not in contact with each other even after being tightened. Next, embodiments of the present invention will be described based on the drawings. FIG. 1 is a cross-sectional view showing an annular gasket used in an embodiment of the present invention when it is molded with a mold. The annular gasket 1 has an approximately L cross section consisting of an almost vertical rising portion 1a and a horizontal portion 1b.
This annular gasket 1 injects molten synthetic resin into the molding part of the mold 10 (the part occupied by the annular gasket 1 in FIG. 1) through a gate 11, and cools it to solidify it. In particular, the mold 10 for molding includes a rising portion 1 of the annular gasket 1.
A gate 11 is located at a position adjacent to the outer peripheral edge of the upper surface of a.
is provided in this annular gasket 1,
Resin 1c, which was injected into the gate 11 of the mold 10 when the annular gasket 1 was molded with a mold, is attached to the outer peripheral end of the upper surface of the rising portion 1a. After taking out the annular gasket 1 from the mold 10, the resin 1c injected into the gate of the mold is removed by moving a sliding blade (not shown) in the direction indicated by the arrow in FIG. disconnected. Due to such cutting, a part of the resin 1c injected into the gate of the mold may remain on the outer peripheral edge of the upper surface of the rising part 1a of the annular gasket 1, as shown in FIG. As can be seen from FIG. 4, the portion does not come into contact with the positive electrode can 6 and the negative electrode terminal plate 8, so that the sealing performance of the battery will not be deteriorated. FIG. 3 is a sectional view showing an embodiment of the button-shaped battery of the present invention, and FIG. 4 is an enlarged view of the main parts thereof. In the figure, reference numeral 1 denotes an annular gasket, and as shown in FIG. , obtained by cutting in the direction indicated by the arrow in FIG. That is, the annular gasket 1 is obtained by cutting the resin 1c injected into the gate of the mold when the annular gasket 1 is molded in a mold at the outer peripheral end of the upper surface of the rising portion 1a. Further, 2 is a positive electrode mixture, and 3 is a metal annular pedestal fixed to the peripheral edge of the positive electrode mixture 2. 4 is a separator, 5 is an electrolyte absorber, and 6 is a positive electrode can filled with the above-mentioned positive electrode mixture 2 and the like. 7 is a negative electrode material, and 8 is a negative electrode terminal plate. Annular gasket 1
is arranged between the positive electrode can 6 and the negative electrode terminal plate 8, and by tightening the opening peripheral wall 6a of the positive electrode can 6 inward, the outer peripheral surface of the rising portion 1a of the annular gasket 1 is connected to the opening peripheral wall of the positive electrode can 6. The inner peripheral surface of the rising portion 1a of the annular gasket 1 is pressed against the peripheral edge 8a of the negative electrode terminal plate 8 to seal the opening of the positive electrode can 6. As is clear from FIG. 4, the upper surface of the rising portion 1a of the annular gasket 1 remains close to the positive electrode can 6 and the negative electrode terminal plate 8 even after the opening peripheral wall 6a of the positive electrode can 6 is tightened inward.
Do not come into contact with. Further, the resin 1c injected into the gate of the mold during molding of the annular gasket 1 remaining on the outer peripheral edge of the upper surface of the rising portion 1a of the annular gasket 1 does not come into contact with the positive electrode can 6 and the negative electrode terminal plate 8.
Therefore, the resin 1c does not deteriorate the sealing performance of the battery. In addition, in FIGS. 2 and 4, in order to make it easier to understand the resin 1c injected into the gate of the mold when molding the annular gasket 1, the resin 1c injected into the gate of the mold and the original annular gasket 1 are shown. The boundary with the resin constituting the material is indicated by a dashed line. The following Table 1 shows the results of a leakage resistance test of the button type battery of the present invention having the above-mentioned configuration and a conventional button type battery. The leakage resistance test was carried out by storing 100 of both batteries in an atmosphere at 60℃ and 90% relative humidity for a specified period of time, and checking for leakage of electrolyte.The results showed that there was no leakage of electrolyte. It is indicated by the number of batteries generated. Note that in Table 1, conventional button batteries are indicated as conventional products.

[Table] All button batteries used in the test were SR43.
It is a type of silver oxide battery, and the electrolyte is a 35% by weight aqueous potassium hydroxide solution in which zinc oxide is dissolved. Both annular gaskets 1 are made of nylon 11,
As mentioned above, the annular gasket 1 used in the button-type battery of the present invention has the outer peripheral edge of the upper surface of the rising portion 1a, which is injected into the gate of the mold when the annular gasket 1 is molded in a mold. This is a cut of resin 1c. On the other hand, the annular gasket 1 used in the conventional button-type battery has a fifth
As shown in the figure, the resin 1c injected into the gate of the mold, which was attached to the upper side surface of the rising portion 1a, is cut in the direction shown by the arrow in FIG. As shown in Table 1, the button type battery of the present invention had a smaller number of batteries with electrolyte leakage than the conventional button type battery, and had excellent leakage resistance. It should be noted that the reason why electrolyte often leaks in conventional button-type batteries is that the annular gasket used leaks the resin injected into the gate of the mold when molding the annular gasket at the upper side of the rising part. This is thought to be due to the fact that, since the annular gasket was cut, there was a partial protrusion or a decrease in wall thickness on the outer circumferential surface of the rising portion of the annular gasket, which deteriorated the sealing performance.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an annular gasket used in an embodiment of the present invention in a molded state. FIG. 2 is an enlarged sectional view showing one aspect of the resin injected into the gate of the mold for the annular gasket shown in FIG. 1. FIG. 3 is a sectional view showing an embodiment of the button-type battery of the present invention, and FIG. 4 is an enlarged view of the main part of FIG. 3. FIG. 5 is a sectional view showing a state in which an annular gasket used in a conventional button-type battery is molded with a metal mold. FIGS. 6 and 7 are enlarged cross-sectional views of essential parts showing the resin injected into the gate of the mold for the annular gasket shown in FIG. 5, respectively. FIG. 8 is an enlarged view of the main parts of a conventional button-type battery. DESCRIPTION OF SYMBOLS 1... Annular gasket, 1a... Standing part, 1b... Horizontal part, 1c... Resin injected into the gate of the mold, 6... Positive electrode can, 6a... Opening peripheral wall, 8... Negative electrode terminal plate , 8a...periphery.

Claims (1)

[Scope of utility model registration request] A substantially L-shaped annular gasket 1 whose cross section is formed by injecting molten synthetic resin through a gate into the molding part of a mold, cooling it, and solidifying it, the cross section of which is composed of an almost vertical rising part 1a and a horizontal part 1b.
is placed between the positive electrode can 6 and the negative electrode terminal plate 8, and by tightening the opening peripheral wall 6a of the positive electrode can 6 inward, the outer peripheral surface of the rising portion 1a of the annular gasket 1 is connected to the opening peripheral wall of the positive electrode can 6. 6a, and the inner circumferential surface of the rising portion 1a of the annular gasket 1 is press-contacted to the peripheral edge 8a of the negative electrode terminal plate 8 to seal the opening of the positive electrode can 6. The gasket 1 is obtained by cutting the resin 1c injected into the gate of the mold when the annular gasket 1 is molded in a mold at the outer peripheral end of the upper surface of the rising portion 1a, and the annular gasket 1 A button type battery characterized in that the upper surface of the rising portion 1a does not contact the positive electrode can 6 and the negative electrode terminal plate 8 even after the opening peripheral wall 6a of the positive electrode can 6 is tightened inward.