JPH056302B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lid for a battery container, and more particularly to a lid in which the shape and properties of the caulking portion with the main body of the battery container, which greatly influences leakage of electrolyte, are improved.

FIG. 1 is a half-sectional front view of a conventional silver oxide battery for explaining an interesting prior art of the present invention. FIGS. 2 to 8 are central vertical cross-sectional end views sequentially illustrating the manufacturing process of the lid shown in FIG. 1.

The silver oxide battery shown here is a so-called button-type battery that is widely used as a power source for electronic wristwatches, for example. Regarding its structure, the anode can 1, which forms the main body of the battery case, is made of, for example, nickel-plated iron, and an anode active substance 2, a separator 3, and a cathode active substance 4 are arranged in layers in this order. Ru. A cathode can 5 serving as a lid for the battery container can is placed over the cathode active substance 4. The cathode tube 5 is made of stainless steel, and has a copper layer formed on its inner surface and a nickel layer formed on its outer surface.

The cathode can 5 includes a peripheral edge 6 having a U-shaped cross section. A packing 7 is disposed substantially outside the peripheral edge 6, and engages with the peripheral edge 6 through the packing 7 when the open end edge of the anode can 1 is caulked inward. This achieves a sealed structure to prevent electrolyte leakage.

The above-described cathode can 5 has a folded peripheral edge 6 with a U-shaped cross section, so the structure is designed to strengthen the buckling force of the caulked portion, but the hardness of this caulked portion is Since it greatly contributes to preventing electrolyte leakage, it is desirable to further strengthen it.

The reason why the peripheral edge 6, which is the caulking part of the conventional cathode can 5, is not sufficiently hard is considered to be due to the manufacturing process described below. First, in a conventional manufacturing process, as shown in FIG. 2, a blank 8 cut into a desired size is prepared. Next, as shown in FIG. 3, the blank 8 is pressed by an upper drawing die 9 and a lower drawing die 10, and the blank 8 undergoes a first drawing process. At this time, blank 8
The outer periphery of is tightly clamped, for example, to prevent wrinkles from forming, and therefore the wall thickness of this outer periphery is reduced. Next, as shown in Figure 4,
A second drawing step is performed by the upper drawing die 11 and the lower drawing die 12. Again, the workpiece 1
The wall thickness of the outer periphery of No. 3 is made thinner. Next, as shown in FIG. 5, the compound 13 is cut to have a desired outer diameter. Next, as shown in FIG. 6, the flange portion 14 on the outer periphery of the workpiece 13 is preliminarily raised. Furthermore, as shown in FIG. 7, the flange portion 14 is completely raised. Finally, as shown in FIG. 8, by further pressing the flange portion 14 inward, the distance between the flange portion 14 and the main body portion of the workpiece 13 is narrowed. As a result, cathode tube 5 is obtained,
The flange portion 14 comes to constitute a part of the peripheral edge portion 6 having the above-mentioned U-shaped cross section.

In such conventional processes, it has been found that the processes shown in FIGS. 3 and 4 and FIGS. 6 to 8 pose particular problems. Regarding this, the 9th
This will be explained with reference to the figures. FIG. 9 is an enlarged view of the periphery of the lid.

The first problem is that in the steps shown in FIGS. 3 and 4, the thickness of the outer periphery of the blank 8 or the workpiece 13 is reduced. This outer peripheral portion will eventually be brought to a position on the outer peripheral side 6a of the peripheral edge portion 6 having a U-shaped cross section. Therefore, this thinned outer peripheral side 6a naturally has inferior strength. The second problem is the sixth
This occurs when the flange portion 14 is folded back to form the peripheral edge portion 6 having a U-shaped cross section in the steps shown in FIGS. That is, in the steps shown in FIGS. 6 and 7, only a natural curved portion is formed by folding back the flange portion 14, and no work hardening occurs. In this state, the process shown in FIG. 8 is carried out, and as shown in FIG.
If pressure is applied to narrow the distance between a and the inner peripheral side 6b, the curved portion 6c will become thinner and weaker.

Due to these reasons, the outer peripheral side 6a of the peripheral edge 6, which needs to sufficiently withstand the pressure generated in the caulking process,
This results in a decrease in strength.

In short, in the past, it was simply thought that by folding the periphery into a U-shaped cross section, the strength of the cathode can, that is, the lid of the battery container can be increased, and the ability to prevent electrolyte leakage would be increased accordingly. . That is,
It was thought that leakage resistance could be satisfied just by applying simple processing. However, it has become clear that there is still room for improvement in terms of strength and leakage resistance.

This invention attempts to improve these remaining problems. Briefly speaking, the present invention relates to a technique for improving the cross-sectional shape of the lid of a battery container can. In other words, by changing the cross-sectional shape of the battery container lid, a lid with a certain volume can be made to have the maximum effect in terms of strength and leakage resistance. . The entire volume of the lid most efficiently contributes to improving strength and leakage resistance.

More specifically, the lid of the battery container can according to the present invention has a peripheral edge portion having a U-shaped cross section, and this peripheral edge portion having a U-shaped cross section extends from the center of the battery container can to the peripheral edge. The cross-sectional shape has a cross-sectional shape in which the portion bends to one side to form the inner half of the circumferential edge having a U-shaped cross section, and the circumferential edge having the U-shaped cross-section further bends to the other side to form the outer half of the circumferential edge having a U-shaped cross-section. The peripheral edge portion, which has a U-shaped cross section, presses the tip of the outer half toward one side, and presses the continuous curved portion of the outer half and inner half toward the other side, and presses it laterally. By pressing the outer half of the U-shaped cross section facing toward the side and pressing the curved continuous portion of the outer half and the inner half facing the other side and toward the side, the peripheral edge of the U-shaped cross section is press-deformed and strengthened. It is characterized by its shape structure.

According to this invention, in particular, the peripheral edge portion having a U-shaped cross section is formed by pressing the outer half of the U-shaped cross section facing one side and bending the outer half and the inner half facing the other side and facing laterally. Due to the pressure, the periphery of the U-shaped cross section is deformed and strengthened.
To provide a battery container lid with improved lid strength and leakage resistance.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a battery container lid that can sufficiently withstand the pressure of caulking, thereby achieving a desired sealing structure and preventing electrolyte leakage.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the structure of a battery container lid according to an embodiment of the present invention will be clarified by explaining its manufacturing method with reference to the drawings.

10 to 12 are central vertical cross-sectional end views sequentially showing steps included in a method for obtaining a battery container lid according to an embodiment of the present invention. FIG. 13 is an enlarged view of the process shown in FIG. 12.

Referring to FIG. 10, a blank 21 is prepared which is cut to match the size of the cathode can used as the lid of the battery can. This blank 21
The size of is determined by taking into consideration the bending allowance of the bending process described later.

Referring to FIG. 11, the blank 21 is subjected to a bending process on its outer periphery using a punch 22 and a die 23. As shown in FIG. At this time, since the bent portion 24 of the blank 21 existing between the punch 22 and the die 23 has sufficient clearance, the wall thickness of the blank 21 is not reduced as in drawing process. . This bent and raised portion 24 is the portion that should become the outer portion of the periphery of the U-shaped cross section of the battery container lid, and its outer diameter is the same as that of the die 2.
The inner diameter of the die 23 is selected to be equal to the outer diameter of the cathode can to be obtained.

With reference to FIGS. 12 and 13, a blank 21 as a workpiece obtained in the process of FIG.
is pressed between the punch 27 and the knockout 28 while the outward expansion of its outer periphery is regulated by the die 26, that is, while it is confined by the die 26, and is forcibly formed into a desired shape. be done. To be more specific, the punch 27 includes an action portion 29 that presses the tip of the bent portion 24.
is formed. The action portion 29 forms a horizontal action surface 29a facing downward. The knockout 28 includes a central acting portion 31 that presses the center of the main plane of the blank 21 and faces upward.
Preferably, an inclined working surface 32 facing outward and upward is formed on the outer circumferential surface of. Also, knock out 28
preferably extends horizontally outwardly from the outer lower end of the inclined working surface 32 and faces upwardly.
Equipped with.

When the blank 28 is pressed by the punch 27 and the knockout 28 as described above, the central part of the peripheral surface of the blank 21 is formed into a shape that bulges upward, and as a result, an outer half is formed on the periphery of the main plane part. A U-shaped cross-sectional portion is formed, consisting of the inner half and the inner half.

Additionally, in preferred embodiments of the invention, the thickness of the bent portion 24 can be increased as desired. That is, in the preferred embodiment, due to the action of the inclined action surface 32, the wall thickness of the inner circumferential side 33b at the lower end of the circumferential edge part 33, which has a U-shaped cross section and is partially constituted by the bending and raising part 24, is increased to the outer circumferential side 33a. Be biased. Then, the outer circumferential side 33a, to which a part of the meat on the inner circumferential side 33b has moved, is further connected to the horizontal action surface 29a of the punch 27 and the knockout 28.
is compressed between the horizontal working surface 36 of the As a result, a wall thickness sufficient to withstand the force in direction A, which is the maximum stress applied during caulking, is achieved. Furthermore, B that is added secondarily during caulking
It is also able to withstand directional forces.

Further, in a preferred embodiment of the present invention, the mutual pressure between the punch 27 and the knockout 28 allows the punch 27 and the knockout 28 to press against each other.
It should also be noted that work hardening occurs in 3a. Furthermore, it should be noted that on the inner circumferential side 33b, the inclined surface 30 formed along the inclined working surface 32 of the knockout 28 has extra thickness and functions as a rib. This work hardening and rib effect have a mechanically advantageous effect on caulking. Furthermore, the work hardening and rib effect described above are advantageous in terms of preventing liquid leakage, that is, in terms of adhesion to the packing 7 (FIG. 1).

Furthermore, according to a preferred embodiment of the invention:
The horizontal action surface 29a of the punch 27 acts on the tip of the bent portion 24, and the upward horizontal surface 3
Ensure that 7 is formed. Further, the horizontal action surface 36 of the knockout 28 acts on the lower end of the outer peripheral side 33a of the bent and raised portion 24, forming a downward horizontal surface 38 there. Then, an outward vertical surface 39 is formed extending from the outer peripheral end of the upward working surface 37 to the outer peripheral end of the downward horizontal surface 38 . Therefore, a relatively sharp protruding edge 40 is formed at the intersection of the upward horizontal surface 37 and the outward vertical surface 39, and a relatively sharp protruding edge 40 is formed at the intersection of the downward horizontal surface 38 and the outward vertical surface 39. , a relatively sharp protruding edge 41 is formed. These edges 40, 41 bite into the packing 7 (FIG. 1) and further contribute to preventing liquid leakage. That is, each of the edges 40 and 41 strongly engages with the packing 7 along each line extending all the way around the inner peripheral surface of the packing 7, so that the leakage of the electrolyte can be advantageously prevented.

FIG. 14 shows a test method conducted to confirm the effectiveness of the preferred embodiment of the present invention. 14th
Referring to the figure, cathode tube 5 obtained by the conventional method
and the cathode can 5 obtained by the method of the present invention are each held by a jig 34 and placed vertically. Then, pressure was applied from above using a pressurizer 35, and the maximum compressive load at the time of primary buckling was measured. The average value measured using this method for five samples was 16.60 kg, whereas the conventional one was 16.60 kg.
The weight of the product according to this invention was 17.25Kg, and it was found that the product according to this invention was superior.

Furthermore, when the hardness of each part of the conventional product and the product according to the present invention was measured, the following results were obtained. In other words, with a Bitkers hardness tester,
The Vickers hardness was determined for each part a to e in FIGS. 9 and 13 under the measurement conditions of 200 g load and 15 seconds. According to this, at position a, the conventional one is 208 and the one of this invention is 205. At position b, the conventional one is 296 and the one of this invention is 353. At position c, The conventional one is 306 and the one of this invention is 381. At position d, the conventional one is 369 and the one of this invention is 446. At position e, the conventional one is 369. The result of this invention was 420. This confirms that work hardening occurs particularly in the peripheral edge portion 33 having a U-shaped cross section.

In the above-described embodiment, an outward vertical surface 39 that extends straight in the vertical direction is formed on the outer peripheral side 33a of the peripheral edge portion 33 having a U-shaped cross section. Moreover,
According to this outward vertical surface 39, the conventional outer peripheral side 6
A (FIG. 9) is formed by extending from the curved portion 6c in a naturally curved state, so that the dimension in the vertical direction of the surface that directly extends can be further increased.
This outward vertical surface 39 is an important part to ensure more secure contact with the packing 7 when caulking is performed in the A direction (Fig. 13) in the caulking work of the cathode can 1. The longer it lasts, the better the leakage will be prevented. According to a preferred embodiment of the present invention, it is easy to form the above-mentioned vertically extending outward vertical surface 39 to be longer.

As described above, according to the battery container lid of the present invention, the peripheral edge portion having a U-shaped cross section can be pressed by the outer portion having a U-shaped cross section facing one side, and facing the other side and facing laterally. The peripheral edge of the U-shaped cross section is pressed and deformed by the pressure of the continuous curved portions of the outer half and the inner half, resulting in a strengthened structure that can sufficiently withstand the load applied during caulking. Therefore, caulking can be performed with sufficient strength, making it possible to realize a more reliable sealing structure, which is advantageous in preventing electrolyte leakage.

In this way, the present invention effectively utilizes the limited volume of the lid by improving the cross-sectional shape of the lid of a small-sized so-called button-type battery by press molding. This aims to improve the strength and leakage resistance of the lid.

Note that the present invention is not limited to silver oxide batteries, but is equally applicable to battery case lids for silver peroxide batteries, mercury batteries, lithium batteries, sealed nickel cadmium batteries, alkaline manganese dry batteries, and the like.

[Brief explanation of the drawing]

FIG. 1 is a half-sectional front view of a conventional silver oxide battery for explaining an interesting prior art of the present invention. FIGS. 2 to 8 are central vertical cross-sectional end views sequentially illustrating the manufacturing process of the lid shown in FIG. 1. FIG. 9 is an enlarged view of the periphery of the lid. Figures 10 to 12
The drawings are central longitudinal sectional end views sequentially showing steps included in a method of manufacturing a battery container lid according to an embodiment of the present invention. FIG. 13 is an enlarged view of the process shown in FIG. 12. FIG. 14 shows a test method carried out to confirm the effects of the present invention. In the figure, 1 is an anode can (main body), 5 is a cathode can (lid), 7 is a packing, 30 is an inclined surface, 3
3 is a peripheral edge portion having a U-shaped cross section, 33a is an outer peripheral side, 33
b is an inner peripheral side, 37 is an upward horizontal surface, 38 is a downward horizontal surface, 39 is an outward vertical surface, and 40 and 41 are edges.

Claims (1)

[Scope of Claims] 1. A battery case having a peripheral edge having a U-shaped cross section that engages with the main body of the battery case through packing when the opening edge of the main body of the battery case is caulked inward. , wherein the peripheral edge portion having a U-shaped cross section is curved to one side from the center portion of the lid of the battery container can, forming an inner half of the peripheral edge portion having a U-shaped cross section; The peripheral edge portion having a U-shaped cross section is further curved to the other side to form an outer half of the peripheral edge portion having a U-shaped cross section, and the peripheral edge portion having a U-shaped cross section is the peripheral edge portion having a U-shaped cross section. a first molding member having an action surface that presses the tip of the outer half of the U-shaped cross section toward the one side; A second molded member having a working surface that presses the continuous curved portion of the half and inner half toward the other side and presses the battery case canister in the opposite direction. By being pressed toward the other side, the tip of the outer half is pressed toward the one side, and the continuous curved portion of the outer half and the inner half is pressed toward the other side and outward, By pressing the outer half of the U-shaped cross section facing the one side and pressing the curved continuous portion of the outer half and the inner half facing the other side and outward, the peripheral edge portion of the U-shaped cross section is pressed. The outer half is formed with an upward surface, a downward surface, and an outward surface connecting these surfaces, and the peripheral edge of the U-shaped cross section is pressed outward to be thickened and strengthened. A lid for a battery container can, characterized in that the inner half of the lower end of the periphery of a U-shaped cross section has a shape structure including an inclined surface facing inward and downward, the flesh of that part being biased outward. . 2. The battery case can lid according to claim 1, wherein the outer half of the peripheral edge of the U-shaped cross section is thicker than the inner half. 3. The battery case according to claim 1, wherein in the curved continuous portion of the outer half and the inner half of the U-shaped cross section, the inner circumferential side is biased toward the outer circumferential side. lid.