JP2022051003A - Battery lid - Google Patents

Abstract

To protect a valve so that it does not prevent the valve from opening without the need for a separate member for valve protection to a battery lid composed of a metal plate in which the valve, which opens at a predetermined pressure, and a surrounding plate section connected to the valve are integrally formed.SOLUTION: A valve 1 is composed of a pressure-receiving portion 3 protruding to one side and a thin-walled portion 4 connecting the pressure-receiving portion 3 and the surrounding plate 2, which is thinner than the pressure-receiving portion 3 and the surrounding plate 2. The pressure-receiving portion 3 has a protective cover 5 that extends hollowly to cover the thin-walled portion 4 from one side.SELECTED DRAWING: Figure 1

Description

The present invention relates to a metal plate battery lid used for sealing a battery case.

Conventionally, in lithium-ion batteries, nickel-metal hydride batteries, and the like, as a battery case for accommodating the power generation element, a sealed type in which a battery lid is attached to the cylinder mouth of a bottomed tubular case body has been adopted.

As the battery lid, a valve made of a valve that opens at a predetermined pressure and a metal plate in which a peripheral plate portion connected to the valve is integrally formed is widely used. The valve has a thin-walled portion whose plate thickness is thinner than that of the surrounding plate portion, and when the battery internal pressure reaches a predetermined pressure, the valve starts to cleave from the thin-walled portion. The valve functions as a safety valve to prevent the battery case from exploding when the internal pressure of the battery rises abnormally. This type of battery lid is generally mass-produced by press working with a progressive mold. At the time of manufacture, the dimensions of the thin-walled portion are controlled so that the valve opens at a predetermined pressure.

There is a concern that foreign substances such as electrolytic solution, water, and oil may adhere to the battery lid as described above. When such a foreign substance adheres to the thin-walled portion of the valve, it causes corrosion and the pressure at the time of cleavage (cleaving pressure) changes from a predetermined pressure. In order to prevent this, a film or a seal is adhered to a metal plate to cover the valve, or a protective resin is applied to the valve (Patent Documents 1 to 3).

Japanese Patent No. 6252877 Japanese Patent No. 4100332 Japanese Patent No. 5407683

However, in order to protect the valve from foreign matter adhering to the valve and preventing the cleavage pressure from changing from the predetermined pressure, if a film or the like is separately attached as in Patent Documents 1 to 3, it is costly to procure parts and carry out the separation process. There is a problem that requires. It may also happen that the film or the like interferes with the smooth cleavage of the valve.

In view of the above background, an object to be solved by the present invention is to protect the valve so as not to separately attach a valve protecting member to the battery lid and to prevent the valve from opening.

In order to achieve the above-mentioned problems, the present invention relates to a battery lid made of a metal plate in which a valve that opens at a predetermined pressure and a peripheral plate portion connected to the valve are integrally formed. It consists of a pressure receiving portion protruding to the side and a thin-walled portion that is thinner than each of the pressure receiving portion and the surrounding plate portion and connects the pressure receiving portion and the surrounding plate portion, and the pressure receiving portion has the thin-walled portion on one side. It adopts a configuration having a protective cover that extends hollowly so as to cover from the side.

According to the above configuration, the pressure-receiving portion protruding to one side can be made thicker than the thin-walled portion so that even if foreign matter adheres to the pressure-receiving portion, there is no concern that the cleavage pressure will be affected. Further, when the valve is pressed, a protective cover extending hollowly toward the thin wall portion can be integrally formed with the pressure receiving portion by utilizing the thickness of the protruding portion as the pressure receiving portion. The hollow protective cover covers the thin part from one side to prevent foreign matter from adhering to the thin part that determines the opening pressure of the valve, and the protective cover comes into contact with other parts of the metal plate. It is possible to secure a gap so as not to prevent the valve from opening.

Therefore, the battery lid according to the present invention can protect the valve without attaching a valve protecting member to the battery lid and not hindering the opening of the valve by adopting the above configuration.

An enlarged cross section of the battery lid according to the first embodiment of the present invention shown by the cut surface of the line I-I in FIG. Top view showing the battery lid of FIG. Enlarged view of the valve of FIG. Enlarged view near the protective cover in FIG. Sectional drawing which shows the process of the half punching process for forming the pressure receiving part of FIG. Sectional drawing which shows the pressing process following FIG. FIG. 6 is a cross-sectional view showing the engraving process of the rupture groove following FIG. FIG. 7 is a cross-sectional view showing a curling process for molding the protective cover. FIG. 8 is a cross-sectional view showing a state in which the protective cover is molded by the curling process of FIG. Sectional drawing which shows the main part of the battery lid which concerns on 2nd Embodiment of this invention.

Hereinafter, the first embodiment as an example of the battery lid according to the present invention will be described with reference to the accompanying drawings.

The battery lid shown in FIGS. 1 and 2 is composed of a metal plate in which a valve 1 that opens at a predetermined pressure and a peripheral plate portion 2 connected to the valve 1 are integrally formed. This battery cover exemplifies the one for a square battery. The peripheral edge of the battery lid is joined to the cylinder mouth portion (not shown) of the case body having a bottomed cylinder.

The metal plate is generally a material that can be pulled out from an anchorer and press-processed by a progressive mold, and a typical example thereof is an aluminum alloy plate or the like.

The valve 1 includes a pressure receiving portion 3 protruding to one side, and a thin-walled portion 4 thinner than the pressure receiving portion 3 and connecting the pressure receiving portion 3 and the surrounding plate portion 2. Here, the "one side" refers to the direction of traveling in one direction in the thickness direction, and the direction of traveling in the direction opposite to one side is referred to as "the other side". In FIG. 1, the thickness direction corresponds to the vertical direction, one side corresponds to the upper side, and the other side corresponds to the lower side.

The surrounding plate portion 2 surrounds the valve 1 and is thicker than the thin-walled portion 4 and is continuous around the thin-walled portion 4. The thickness of the surrounding plate portion 2 is the thickness of the portion adjacent to the valve 1, and is set to be substantially the same as the plate thickness of the metal plate used as the material.

The pressure receiving portion 3 protrudes high from the thin wall portion 4 to one side. The base pillar portion of the pressure receiving portion 3 is a solid columnar portion thicker than the thin wall portion 4. The thin-walled portion 4 extends in an annular shape surrounding the base pillar portion of the pressure receiving portion 3.

The plate surface on the other side of the pressure receiving portion 3 and the thin wall portion 4 forms a concave bottom surface portion having a depth from the plate surface on the other side of the surrounding plate portion 2 to one side, and is formed into a flat surface shape. ing. Here, the flat surface shape means a surface shape extending in a direction perpendicular to the thickness direction.

The pressure receiving portion 3 has a protective cover 5 extending hollowly so as to cover the thin wall portion 4 from one side. The protective cover 5 protrudes further toward one side from the base pillar portion of the pressure receiving portion 3 in a cylindrical shape, and has a curl shape bent toward the thin wall portion 4 on the tubular tip side.

As shown in FIGS. 3 and 4, the thin-walled portion 4 has a burst groove 6 engraved so as to pass through a portion between the pressure receiving portion 3 and the surrounding plate portion 2 with a groove depth in the thickness direction. The rupture groove 6 is engraved on one side of the thin wall portion 4. The rupture groove 6 extends in an annular shape concentric with the circumferential shape of the outer circumference of the pressure receiving portion 3. The groove cross-sectional shape of the rupture groove 6 is V-shaped.

Of the thin-walled portions 4, the plate surface connected between the burst groove 6 and the pressure receiving portion 3 and the plate surface connected between the burst groove 6 and the surrounding plate portion 2 are each formed into a flat surface shape. The plate surface connected between the rupture groove 6 and the surrounding plate portion 2 and the plate surface on one side of the plate portion 2 are flush with each other. The pressure receiving portion 3 has a protruding height on one side with respect to the surrounding plate portion 2.

The tip portion 7 of the protective cover 5 faces the surrounding plate portion 2 with a gap. The facing gap is set to the minimum among the gaps formed by the protective cover 5 with respect to the thin-walled portion 4 and the surrounding plate portion 2.

The battery lid shown in FIGS. 1 and 2 is joined to the cylinder mouth portion (not shown) of the case body with one side of the battery lid facing the outside side of the battery. Even if a foreign substance (not shown) such as an electrolytic solution, water, or oil is applied to one side (external side) of the battery lid, the thin-walled portion 4 is covered from one side by the protective cover 5, so that the foreign matter is covered by the thin-walled portion 4. It is prevented from adhering to the protective cover 5.

Further, when the internal pressure of the battery (not shown) rises, the pressure (battery internal pressure) acts on the valve 1 from the other side (internal side of the battery) to one side (outside side), and the pressure receiving portion 3 and The thin-walled portion 4 is pushed to one side with respect to the surrounding plate portion 2, and the valve 1 swells. At this time, since the thickness of the thin-walled portion 4 is sufficiently thinner than the thickness of each of the pressure receiving portion 3 and the surrounding plate portion 2, as shown by the alternate long and short dash line in FIG. 4, the thin-walled portion is affected by the internal pressure of the battery. 4 will be pulled to one side. This tensile stress changes according to the magnitude of the battery internal pressure acting on the valve 1. When the pressure acting on the valve 1 reaches a predetermined pressure, the valve 1 bursts without being able to withstand the tensile stress, especially at the bottom of the thin burst groove 6, and the valve 1 is opened from this point. Then, as the rupture progresses rapidly along the groove bottom of the rupture groove 6, the open area of the valve 1 rapidly expands. At this time, since the protective cover 5 is a part of the pressure receiving portion 3 located hollow on one side of the thin wall portion 4 and the surrounding plate portion 2, the other portion of the pressure receiving portion 3 and the pressure receiving portion 4 of the thin wall portion 4 are received. It can be easily detached from the battery lid together with the ruptured fragment portion on the portion 3 side, and there is no concern that the valve 1 may be cleaved.

Since the gap between the tip portion 7 of the protective cover 5 and the surrounding plate portion 2 is the only foreign matter intrusion route, it is preferable to make it as narrow as possible. The size of the gap is preferably 0.5 mm or more and 2.0 mm or less in consideration of feasibility in press working, foreign matter intrusion prevention property, and guarantee of the opening pressure of the valve 1.

5 to 9 show examples of a method of pressing the above-mentioned valve 1 with a progressive remittance mold. The upper side in these figures corresponds to one side of the above-mentioned battery lid.

First, as shown in FIG. 5, the work portion W of the strip-shaped metal plate is fed between the punch P1 of the lower die and the dies D1 and D2 of the upper die, and the punch P1 and the dies D1 and D2 are on the upper side of the work portion W. The solid columnar portion 11 is projected and the circumference of the solid columnar portion 11 is thinned by molding so that the solid columnar portion 11 is convex and concave on the lower side.

The work portion W is fed between the lower die D3 shown in FIG. 6 and the upper die punches P2 and D4, and a part of the solid columnar portion 11 is recessed downward to form a plastically flowing meat portion. Is projected further upward in a cylindrical shape. As a result, the solid columnar base pillar portion 12 and the tubular portion 13 that is concentric with the base pillar portion 12 and protrudes higher upward are formed.

The work portion W is fed between the lower die D5 and the upper punch P3 shown in FIG. 7, and the rupture groove 6 is stamped on the thin portion around the base pillar portion 12 with the upper die stamp P3. do. As a result, the molding of the thin wall portion 4 is completed.

The work portion W is fed between the lower die D6 and the upper punch P4 shown in FIG. 8, and the tubular portion 13 is curled. By sliding the tubular portion 13 from the tip of the cylinder onto the surface of the punch P4 and bending it in a curl shape toward the thin-walled portion 4, the molding of the pressure receiving portion 3 including the protective cover 5 is completed as shown in FIG.

In the subsequent steps, the work portion W is trimmed to form the peripheral edge of the battery lid shown in FIG.

The plate thickness of the metal plate (corresponding to the thickness of the surrounding plate portion 2) is 2.0 mm or more, more preferably larger than 3.0 mm, and preferably 5.0 mm or less. If the thickness of the metal plate is 2.0 mm or more, it is possible to secure the volume of the meat portion for molding the pressure receiving portion 3 including the protective cover 5, and if it is 5.0 mm or less, the remittance is progressive. It can be pressed by a mold.

As described above, the battery lids shown in FIGS. 1 to 4 are made of a metal plate in which the valve 1 and the surrounding plate portion 2 are integrally formed, and the valve 1 receives pressure protruding to one side. It is composed of a thin portion 3 and a thin portion 4 connecting the pressure receiving portion 3 and the surrounding plate portion 2 thinner than each of the pressure receiving portion 3 and the surrounding plate portion 2, and the pressure receiving portion 3 has the thin wall portion 4 from one side. By having the protective cover 5 extending hollowly so as to cover it, the pressure receiving portion 3 protruding to one side is made thicker than the thin wall portion 4, and even if foreign matter adheres to the pressure receiving portion 3, there is no concern that the cleavage pressure will be affected. Hollow to the thin-walled portion 4 side by utilizing the thickness of the protruding portion (solid columnar portion 11) to be the site and the protruding portion (solid columnar portion 11) to be the pressure receiving portion 3 when the valve 1 is pressed (see FIGS. 5 to 9 as appropriate). The protective cover 5 extending to the surface can be integrally formed with the pressure receiving portion 3. The hollow protective cover 5 covers the thin-walled portion 4 from one side, thereby preventing foreign matter from adhering to the thin-walled portion 4 that determines the cleavage pressure of the valve 1, and the protective cover 5 is a metal plate. A gap can be secured so as not to come into contact with other parts and prevent the valve 1 from opening. By protecting the thin portion 4 with the protective cover 5 formed as a part of the pressure receiving portion 3 of the valve 1 in this way, it is not necessary to protect the valve 1 from the adhesion of foreign matter by a separately attached protective member. Therefore, the battery lids shown in FIGS. 1 to 4 can protect the valve 1 so as not to separately attach a member for protecting the valve 1 to the battery lid and to prevent the valve 1 from opening.

Further, in the protective cover 5, the solid columnar portion 11 is projected to one side from the thin wall portion 4, and a part of the solid columnar portion 11 is recessed to the other side, so that the meat portion that plastically flows is further formed on one side. Since it is formed by projecting it high to the side in a cylindrical shape and bending the tubular portion 13 toward the thin wall portion 4 in a curl shape, the base pillar portion 12 having a thickness that can ignore the influence of corrosion when foreign matter adheres is formed. The thin-walled portion 4 can be protected by the protective cover 5 while remaining in the pressure receiving portion 3.

Further, since the thin-walled portion 4 has a rupture groove 6 engraved so as to pass through a portion between the pressure receiving portion 3 and the surrounding plate portion 2 with a groove depth in the thickness direction, the rupture groove 6 is a protective cover. It is located on the pressure receiving portion 3 side with respect to the tip portion 7 of 5, and a particularly thin burst groove 6 can be protected by the protective cover 5.

Further, since the thickness of the metal plate is 2.0 mm or more, more preferably larger than 3.0 mm and 5.0 mm or less, the entire valve 1 can be formed by press working with a progressive remittance mold.

In the case of the first embodiment, it is important to narrow the facing gap between the tip portion 7 of the protective cover 5 shown in FIG. 4 and the surrounding plate portion 2, but the protective cover 5 is curled as shown in FIG. When the punch P4 is abutted against the work portion W, there is a concern that the thin-walled portion 4 may be cracked. Therefore, the protective cover 5 is formed into a curl shape, that is, with the tip portion 7 of the protective cover 5 in FIG. There is a limit to narrowing the facing gap between the surrounding plate portions 2. Therefore, if it is desired to further enhance the protection performance of the thin-walled portion 4, a portion for preventing foreign matter from entering may be added to the metal plate. A second embodiment as an example thereof is shown in FIG. In the following, only the differences from the first embodiment will be described.

The thin-walled portion 4 according to the second embodiment has a ridge 8 protruding to one side along the tip portion 7 of the protective cover 5. The ridge 8 surrounds the rupture groove 6 and is continuous at a constant height over the entire circumference thereof.

The peripheral plate portion 2 has a protective wall 9 protruding unilaterally along the tip portion 7 of the protective cover 5. The protective wall 9 surrounds the tip portion 7 of the protective cover 5 and is continuous at a constant height over the entire circumference thereof.

The gap between the protective cover 5 and the ridge 8 and the gap between the protective cover 5 and the protective wall 9 should be as narrow as possible within the range where press working is possible. The dimensions of each of these gaps are preferably 1.0 mm or more and 3.0 mm or less in consideration of feasibility in press working, foreign matter intrusion prevention property, and guarantee of the opening pressure of the valve 1.

The ridges 8 and the protective wall 9 can be press-processed by adding concave surfaces for forming the ridges 8 and the protective wall 9 to the upper die D2 shown in FIG. 5, respectively. In this case, in the curling process shown in FIG. 9, the shape and stroke of the punch P4 may be appropriately changed so that the punch P4 does not hit the ridge 8 and the protective wall 9.

In the battery lid according to the second embodiment, since the labyrinth is formed by the protrusion 8 protruding to one side along the tip portion 7 of the protective cover 5 and the protective cover 5, the tip portion 7 and the surrounding plate are formed. Even if foreign matter invades from the facing gap between the portions 2, the ridge 8 can prevent the foreign matter from invading.

Further, in the battery lid according to the second embodiment, since the protective wall 9 protruding to one side along the tip portion 7 of the protective cover 5 and the protective cover 5 form a labyrinth, the tip portion 7 and its surroundings are formed. The protective wall 9 can prevent foreign matter from entering the facing gap between the plate portions 2.

It is not essential to adopt both the ridge 8 and the protective wall 9 as in the second embodiment, and it is possible to protect the thin portion 4 as compared with the first embodiment by using only one of them.

Further, in the above-described embodiment, the valve 1 (pressure receiving portion 3 and thin-walled portion 4) is circular, but it is possible to form a protective cover even when the valve is an elliptical or square valve.

The embodiments disclosed this time should be considered to be exemplary and not restrictive in all respects. Therefore, the scope of the present invention is indicated by the scope of claims and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Valve 2 Peripheral plate 3 Pressure receiving part 4 Thin wall part 5 Protective cover 6 Rupture groove 7 Tip part 8 Protrusion 9 Protective wall

Claims (6)

In a battery lid made of a metal plate in which a valve that opens at a predetermined pressure and a peripheral plate portion connected to the valve are integrally formed.
The valve is composed of a pressure receiving portion protruding to one side and a thin-walled portion that is thinner than each of the pressure receiving portion and the surrounding plate portion and connects the pressure receiving portion and the surrounding plate portion.
The pressure receiving portion is a battery lid characterized by having a protective cover extending hollowly so as to cover the thin-walled portion from one side. In the protective cover, the solid columnar portion is projected to one side from the thin-walled portion, and a part of the solid columnar portion is recessed to the other side, so that the plastically flowing meat portion is further raised to one side and has a tubular shape. The battery lid according to claim 1, which is formed by projecting the tubular portion into a curl shape toward the thin-walled portion. The battery lid according to claim 1 or 2, wherein the thin-walled portion has a burst groove engraved so as to pass through a portion between the pressure receiving portion and the surrounding plate portion with a groove depth in the thickness direction. The battery lid according to any one of claims 1 to 3, wherein the thin-walled portion has a protrusion protruding to one side along the tip end portion of the protective cover. The battery lid according to any one of claims 1 to 4, wherein the peripheral plate portion has a protective wall protruding to one side along the tip end portion of the protective cover. The battery lid according to any one of claims 1 to 5, wherein the thickness of the metal plate is 2.0 mm or more, more preferably more than 3.0 mm and 5.0 mm or less.

Images