KR19990046355A - Sealing plate for a closed type battery, and method for manufacturing it - Google Patents

Abstract

The present invention relates to a sealing plate for closing an opening of a sealed battery container, and provides a sealing plate and a method of manufacturing the same, which can be ruptured reliably when the pressure inside the container becomes excessive when it is excessively simple.

The sealing plate 2 to be mounted on the container 1 is made of a metal plate, and the groove 22 is formed along the contour surrounding the predetermined area on the surface thereof, and at the same time, the bulging portion inside the groove 22 is formed. 23). By setting the thickness of the metal plate of the groove 22 portion appropriately, the breaking pressure at the groove 22 portion of the sealing plate 2 can be adjusted. In the manufacturing method of the sealing plate 2, the metal plate is compressed by press working, the groove 22 is formed, and the bulging part 23 is formed. In addition, when annealing the metal plate, the breaking pressure can be easily adjusted. And if the recessed part 21 is formed in the area | region containing the groove | channel 22 and the bulging part 23, and the groove | channel 22 and the bulging part 23 are formed in the bottom surface of this recessed part 21, good.

Description

Sealing plate of sealed battery and manufacturing method thereof {SEALING PLATE FOR A CLOSED TYPE BATTERY, AND METHOD FOR MANUFACTURING IT}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed plate of a sealed battery and a method of manufacturing the same, and more particularly to a sealed plate having a valve function that can pass through when the pressure in the battery becomes excessive and a method of manufacturing the sealed plate.

In order to prevent the pressure in a sealed battery from becoming excessive, the various safety valve apparatus attached to a container is proposed. For example, Japanese Patent Application Laid-open No. Hei 5-90809 improves a battery provided with a thin breakdown safety valve that closes an opening of an outer tube for storing an electrode group with a sealing plate, thins a part of the outer tube, and breaks with internal pressure. For this purpose, an apparatus has been proposed in which the outer tube is rectangular and a part of the bulging portions other than the sealing portion is made thin.

In addition, Japanese Laid-Open Patent Publication No. 5-59745 uses a safety valve device in which a through-hole is provided in a container of a sealed battery and the through-hole is sealed with a metal foil in the prior art, and it is difficult to set the breakdown pressure of the metal foil to low pressure. In view of this, a diaphragm having a flat surface on the bottom wall of the battery container is formed, and a through hole is formed on the bottom surface of the concave portion, and a diaphragm having a weakened portion is provided. At the same time as closing and mounting, the safety valve apparatus which spot-welded the flat surface and welded the whole periphery of the diaphragm to the flat surface in the vicinity of the weakening part is proposed.

In addition, Japanese Patent Laid-Open No. 6-333548 discloses that the battery case is sealed using a sealing plate with a valve body, and that a thin portion is provided in the bottom of the battery case. Or an explosion-proof sealing plate including a cover plate having a valve hole, a cap-shaped terminal plate having an exhaust hole, and a valve body interposed therebetween to normally close the valve hole of the cover plate by using a battery case made of a thinner or lower bottom part. And the explosion-proof battery is proposed in which the break pressure of the thin part or the bottom of the groove of the battery case is larger than the break pressure of the valve body of the explosion-proof sealing plate due to the gas pressure generated in the battery, and smaller than the breakdown pressure of the battery sealing part. It is.

As for the explosion-proof sealing plate, in Japanese Patent Laid-Open No. 5-74434, after forming the sealing plate for the purpose of stabilizing the breaking pressure of the sealing plate, the pressure at which the valve body of the thin plate breaks through the valve hole of the sealing plate is below. The manufacturing method of the battery explosion-proof sealing plate which has a process which expands a valve body upward at the pressure of and contacts a blade-shaped protrusion, and has been proposed. Regarding such an explosion-proof sealing plate, Japanese Patent Laid-Open No. Hei 6-338305 discloses an explosion-proof sealing plate having a special structure, such as welding a flexible metal explosion-proof valve to a metal strip terminal plate so as to have a stable operating pressure. In addition, as a method of forming a thin portion of a metal explosion-proof valve, a method of attaching a metal stamp or the like and attaching a cross-sectional or wedge-shaped undercut to a C shape, and a method of forming a locally hemispherical thin portion by applying an appropriate load to a steel sphere Is disclosed.

Japanese Patent Laid-Open No. 7-130346 discloses a support member having a through hole as a safety valve for opening a battery internal pressure when an abnormality occurs with respect to a nonaqueous electrolyte secondary battery of a sealed type battery, and a through hole of the support member. A structure is proposed which has a dividing membrane which is provided to be blocked and makes the opening shape of the through hole into a shape having a peak portion projecting inwardly of the through hole.

In Japanese Patent Laid-Open No. 7-130346, a low value of 5 kgf / cm 2 or more is preferable as the pressure at which the pressure resistance is released with respect to the nonaqueous electrolyte secondary battery, but the strength is too high in a conventional safety valve using an aluminum thin film. It is described that the internal pressure of about 30 kgf / cm 2 is required before the safety valve is opened even if the safety valve is provided with a groove.

In other words, at least in the field of sealed batteries, the formation of grooves in metal plates such as aluminum is impractical because it cannot be set to break at low pressure. Therefore, in the method of forming a thin portion of the metal explosion-proof valve disclosed in Japanese Patent Laid-Open No. Hei 6-338350, it is difficult to set to open (break) at a low pressure of 30 kgf / cm 2 or less.

On the other hand, in Japanese Unexamined Patent Application Publication No. 6-333548, the break pressure of the thin portion at the bottom of the case is preferably 15 kgf / cm 2 or more in order to secure the strength of the battery case. However, there is no specific disclosure about a technique that can make the breakage pressure of the thin portion to 15 kgf / cm 2 or less. It is contrary to the description of the fact that it is necessary. Even if the thin part breaking pressure can be set low, the formation of a weaker thin section than the case body should be avoided.

Accordingly, an object of the present invention is to provide a sealed plate of a sealed battery, which is a simple structure and which can be reliably broken and opened to the outside when the pressure in the container becomes excessive in a sealing plate for closing an opening of a container of a sealed battery. do.

In order to solve the above problems, the sealing plate of the sealed battery of the present invention is made of a metal plate for closing the opening of the container of the sealed battery as in claim 1, the groove along the contour surrounding a predetermined area on the surface of the metal plate And forming a bulge that expands to the surface side of the metal plate inside the groove. According to this sealing plate, when the internal pressure of the sealed battery becomes excessively high and the pressure received by the bulge portion exceeds a predetermined pressure, the sealing plate breaks at the groove portion and the swelling portion is opened to communicate with the external space. In this sealing plate, breaking pressure is adjusted by setting the thickness of the metal plate of a groove part suitably.

The sealing plate may be configured to form a recess in a region including the groove and the bulge on the surface of the metal plate as in claim 2, and to form the groove and the bulge on the bottom surface of the recess. In this sealing plate, the breaking pressure is adjusted by appropriately setting the thickness of the metal plate of the recessed part and the groove part.

In the sealing plate as described in claim 1 or 2, as in claim 3, the metal plate may be compressed to form the grooves, the swelling portion may be formed, and the metal plate may be annealed. In this sealing plate, the breaking pressure is adjusted by appropriately setting the annealing treatment and the metal plate thickness of the groove portion.

Further, in the sealed plate manufacturing method of the sealed battery according to the present invention, as described in claim 4, the groove is formed by compression processing along the contour surrounding the predetermined area on the surface of the metal plate, and the groove is formed inside the groove. It is made to form the bulging part which expands to the surface side of a metal plate. In this manufacturing method, the breaking pressure in the groove portion of the sealing plate is adjusted by appropriately setting the thickness of the metal plate of the groove portion.

In the sealed plate manufacturing method of the sealed battery according to the present invention, as described in claim 5, the first predetermined region is pressed against the metal plate to form a recess on the surface of the metal plate, The groove is formed by compression processing along the contour surrounding the predetermined region of 2, and at the same time, a swelling portion is formed inside the groove to swell to the surface side of the metal plate. In this manufacturing method, the breaking pressure in the groove portion of the sealing plate is adjusted by appropriately setting the thicknesses of the recesses and the metal plate of the groove portions sequentially.

In the method of manufacturing the sealing plate according to claim 4 or 5, it is preferable that the metal plate is annealed as in Claim 6. In this manufacturing method, the breaking pressure in the groove portion of the sealing plate is adjusted by appropriately setting the annealing treatment and the metal plate thickness of the groove portion.

BRIEF DESCRIPTION OF THE DRAWINGS The top view of the sealed battery provided with the sealing plate which concerns on one Embodiment of this invention.

2 is a cross-sectional view of a sealed battery with a sealing plate according to an embodiment of the present invention, in which battery components are omitted.

3 is a process chart showing the manufacturing method of the sealing plate according to one embodiment of the present invention.

4 is a front sectional view showing a state in which a recess is formed in a sealing plate in one embodiment of the present invention.

It is a top view which shows the state which formed the recessed part in the sealing plate in one Embodiment of this invention.

6 is a side cross-sectional view showing a state in which a recess is formed in a sealing plate in one embodiment of the present invention.

FIG. 7 is a front sectional view showing a state where recesses, grooves, and bulges are formed in the sealing plate in one embodiment of the present invention. FIG.

8 is a plan view showing a state in which a recess, a groove, and a bulge are formed in a sealing plate in one embodiment of the present invention.

Fig. 9 is a side cross-sectional view showing a state where recesses, grooves, and bulges are formed in the sealing plate in one embodiment of the present invention.

It is process drawing which shows the manufacturing method of the sealing plate which concerns on other embodiment of this invention.

It is a front sectional view which shows the state which formed the recessed part and the bulging part in the sealing plate in another embodiment of this invention.

It is a top view which shows the state which formed the recessed part and the bulging part in the sealing plate in another embodiment of this invention.

It is a side sectional view which shows the state which formed the recessed part and the bulging part in the sealing plate in another embodiment of this invention.

It is a front sectional view which shows the state which formed the recessed part, the groove, and the bulging part in the sealing plate in another embodiment of this invention.

It is a top view which shows the state which formed the recessed part, the groove | channel, and the bulging part in the sealing plate in another embodiment of this invention.

It is a side sectional view which shows the state which formed the recessed part, the groove | channel, and the bulging part in the sealing plate in another embodiment of this invention.

Fig. 17 is a graph showing the measurement results of breaking pressure in the example of the present invention.

[Description of the code]

1 container 2 sealing plates

2a Flange 2b Hole

2c thin plate 3 gaskets

4 Rivet Terminal 21 Concave

22 groove 23 bulge

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described, referring drawings. 1 and 2 show a sealed battery with a sealing plate according to an embodiment, wherein the sealing plate 2 is fitted into the opening 1a of the metal container 1, and the container 1 and the sealing plate 2 are fitted. ) Is hermetically bonded through laser welding over the entire circumference of the opening 1a. The container 1 of this embodiment is formed by forming a rectangular parallelepiped plate made of an aluminum alloy through deep drawing processing, and for example, a component (not shown) of a nonaqueous electrolyte battery is accommodated therein. do.

The sealing plate 2 of this embodiment is made of aluminum alloy, and is formed in rectangular shape so that it may fit in the shape of the opening part 1a of the container 1, and the flange part 2a is formed in the whole periphery. As shown in Fig. 2, a hole 2b is drilled in the center of the sealing plate 2, a gasket 3 is attached to the hole 2b, and is caulked by the rivet terminal 4. Therefore, the hole 2b is sealed by the gasket 3. In addition, both the container 1 and the sealing plate 2 may be formed of different metal materials.

The recessed part 21 is formed in the surface of the sealing plate 2 in the 1st predetermined area | region demarcated in either direction of the rectangular elongate centering on the hole 2b. A second predetermined region is further defined on the bottom surface of the recess 21, and a groove 22 is formed along the contour surrounding the second predetermined region. In addition, in this embodiment, the 1st and 2nd predetermined area | regions, ie, the recessed part 21 and the groove | channel 22, are each formed in elliptical shape in plan view, and are similar to each other, as shown in FIG. And the bulging part 23 is formed inside the groove | channel 22 in the recessed part 21, which will be mentioned later. These concave portions 21 and the grooves 22 are formed by compressing aluminum platelets, and the platelets are annealed to adjust the breaking pressure of the sealing plate 2 at the grooves 22. do. Hereinafter, the recessed part 21, the groove | channel 22, and the bulging part 23 are demonstrated in detail, demonstrating the manufacturing process of the sealing plate 2. As shown in FIG.

3 shows a step in the method for manufacturing the sealing plate 2 according to one embodiment of the present invention, and a white arrow indicates the flow of the step. First, in the deep drawing process (D), a deep drawing process is performed on an aluminum alloy plate (M) by a press device (not shown) which performs a press work including a press machine and a metal mold. Then, a step is formed between the main body portion M1 of the sealing plate 2 and the portion M2 constituting the flange portion 2a later. Subsequently, in the first compression processing step C1, compression processing is performed on the first predetermined region R1 set on the platen M by the press apparatus. Specifically, coining (pressing) is performed, and an elliptical recess 21 is formed as shown in FIGS. 4 to 6. The bottom surface of the recessed part 21 at this stage is formed flat and becomes the thin plate part 2c.

Next, in the shearing process (S), shearing is performed by the press apparatus along the outer shape of the flange portion (2a), and the sealing plate (2) is perforated from the platen (M). The sealing plate 2 is coined again by the press apparatus in the second compression processing step C2, and the contour surrounding the second predetermined region R2 on the bottom surface of the recess 21. A groove 22 is formed along this. At this time, the thin plate portion 2c of the sealing plate 2 expands to the opening side of the concave portion 21 as the groove 22 is formed through coining. Specifically, as shown by the dashed-dotted line in FIGS. 7 and 9, the sealing plate 2 is compressed by the upper mold UD having an annular protrusion on the lower surface and the lower mold LD whose upper surface is flat. At this time, the thin plate portion 2c swells upward in FIGS. 7 to 9, and the bulging portion 23 of the recessed portion is formed at the lower pressure side in a portion where the upper opening side is convex. Thus, since the hydraulic side of the bulging part 23 is formed in the shape of a curved recessed part, it has an area larger than the flat surface of the thin plate part 2c of FIG.

By the above process, the recessed part 21 is formed in the sealing plate 2, and the bulging part 23 is formed in the inside of the groove | channel 22 of the bottom surface. Therefore, when the sealing plate 2 of this state is attached to the container 1, the predetermined | prescribed valve function is ensured by the recessed part 21, the groove | channel 22, and the bulging part 23. As shown in FIG. That is, since the bulging part 23 functions as a hydraulic pressure part, and the sealing plate 2 has the minimum thickness in the groove | channel 22 part, the internal pressure of the container 1 becomes excessive and it adds to the bulging part 23. When the pressure to lose exceeds the predetermined pressure, the sealing plate 2 breaks at the groove 22 and the bulge 23 is dropped. Therefore, since the 2nd predetermined area | region R2 is opened and the inside of the container 1 communicates with an external space, internal pressure falls quickly. The breaking pressure of the sealing plate 2 at this time sets the thickness of the recessed part 21 (thin plate part 2c) suitably, and sets the thickness of the sealing plate 2 of the groove | channel 22 appropriately. I can adjust it. Thus, for example, the breaking pressure can be adjusted to a value near 9.5 kgf / cm 2, and good experimental results can be obtained as shown in the upper part of FIG. 17. In addition, the horizontal axis | shaft of FIG. 17 shows a sample number, and a vertical axis | shaft shows the measured value of a breaking pressure, The upper part shows the measurement result of the breaking pressure of the sealing plate 2, when the annealing process A which is mentioned later is not performed, The measurement result of the breaking pressure of the sealing plate 2 in the case of performing the annealing step (A) is shown.

Said process (D), process (C1), process (S), and process (C2) are all press working, and the recessed part (s) in the sealing plate 2 is made through continuous processing by a press apparatus (not shown). At the same time as the 21 is formed, a groove 22 is formed in the bottom surface thereof, and a swelling portion 23 is formed therein with the formation of the groove 22, so that the sealing plate 2 having a valve function is provided. ) Can be formed into a single part. Therefore, it is possible to provide a sealing plate which can function as a safety valve for a sealed battery at low cost.

When the sealing plate 2 is formed only through the press working as described above, the breaking pressure is not constant for each product as shown in the upper part of the graph of FIG. This is because the groove 22 portion of the sealing plate 2 is hardened through two compression processes. Although this non-uniform distribution is an allowable range, it is not always easy to adjust the breaking pressure to a low value. Can't. Therefore, in this embodiment, as shown in FIG. 3, after performing a 2nd compression processing process C2, heat processing is performed with respect to the sealing plate 2. As shown in FIG. That is, the annealing step A is set and heated at a predetermined temperature and then cooled at a predetermined time.

Accordingly, for example, as shown in the lower part of the graph of FIG. 17, the breaking pressure of the groove 22 of the sealing plate 2 can be easily adjusted to a low value of 6.5 kgf / cm 2 on average. Moreover, the distribution of breaking pressure of the products can also be kept relatively constant, and the breaking pressure can be adjusted to a lower value with greater stability than when the annealing process (A) is not performed (shown at the top of FIG. 17). .

The annealing step (A) may be performed at any stage of the manufacturing step. However, when the annealing step (A) is carried out after passing through the second compression processing step (C2) as shown in Fig. 3, the breaking pressure is more easily adjusted. It is possible to provide a stable product with a relatively constant distribution of breaking pressure. In addition, although the hole 2b is drilled in the sealing plate 2 in the previous stage of annealing process A, you may drill in another process. The shearing step S may be carried out after passing through the second compression processing step C2 or the annealing step A. FIG.

In the said embodiment, although compression processing is performed twice (C1, C2), even if this is performed only once, the breaking pressure can be adjusted to a low value in distribution of a permissible range by addition of the annealing process (A). In other words, for the compression processing, the first compression processing step (C1) is devoted to the second compression processing step (C2) alone, and the platelet M (addition of the deep drawing process (D) if necessary) is added. The groove 22 is formed by coining along a contour surrounding a predetermined area (e.g., the same area as the second predetermined area R2), and the annealing process is also performed. Compared to the conventional method, the breaking pressure can be adjusted to a lower value in the distribution of the allowable range.

10 shows the process in the manufacturing method of the sealing plate which concerns on other embodiment of this invention, and makes 1st compression processing process C1 in the manufacturing process shown in FIG. 3 into 2 processes, The sealing plate 2 shown in FIG. 14 thru | or 16 is formed. In addition, although the process (D) of a deep drawing process is abbreviate | omitted in FIG. 10, it is made similarly to the said manufacturing process. However, also in the manufacturing process of FIG. 3 and FIG. 10, the process (D) of a deep drawing process may be abbreviate | omitted and the sealing plate 2 may be formed in flat plate shape. In the manufacturing process of FIG. 10, coining is performed with respect to the 1st predetermined | prescribed area | region R1 set on the platen M in the first step C11 of a 1st compression process, and is first shown in FIGS. As shown, an elliptical recess 21 is formed. Subsequently, in the post step C12 of the first compression processing, if coining is performed over the entire circumference with a predetermined width along the inner diameter of the recess 21, the sealing plate as shown in Figs. 11 to 13. The bottom face of (2) expands in the opening direction, and a curved bulge 23 is formed on the bottom face of the recess 21.

Next, in the shearing process S, shearing is performed by a press device (not shown) along the outer shape of the flange portion 2a, and the sealing plate 2 is punched out of the platelet M. As shown in FIG. Also in the present embodiment, the shearing step S may be carried out at a later stage. Then, coining is performed by the press apparatus with respect to the sealing plate 2 drilled further to the second compression processing step C2, and as shown in FIGS. 14 to 16, the bottom surface of the recess 21 is formed. The grooves 22 are formed along the contour surrounding the second predetermined region R2 near the bottom of the bulge 23. Accompanying this, the bottom surface of the sealing plate 2 expands in the opening direction, and as shown in FIGS. 14 to 16, an end portion 2d is formed near the bottom of the bulge 23. As a result, it expands in an opening direction more than the bulging part 23 shown in FIG. Therefore, since the pressure-receiving area of the bulging part 23 is enlarged by that, it can be easily adjusted so that it may be broken at low pressure.

In this way, the sealing plate 2 compressed is subjected to heat treatment, specifically, annealing treatment, in the annealing step A of FIG. 10. That is, the sealing plate 2 is heated at a predetermined temperature and then cooled for a predetermined time. As a result, since the thickness of the groove 22 of the sealing plate 2 is set through a total of three times of compression processing and annealing treatment, fine adjustment of the breaking pressure is possible, and the breaking pressure can be easily adjusted to a low value. Therefore, the distribution of the products can be kept relatively constant.

Since this invention is comprised as mentioned above, the effect described below can be seen. That is, in the sealed plate of the sealed battery according to claim 1, a groove is formed on the surface of the metal plate along a contour surrounding a predetermined area, and at the same time, a swelling portion is formed inside the groove to swell to the surface side of the metal plate. Since the metal plate thickness of a groove part is set suitably, the breaking pressure in the groove part of a sealing plate can be adjusted easily. In particular, since the sealing plate is composed of only a single part formed of a metal plate, the sealing plate is inexpensive and can provide a safety valve device for a sealed battery at low cost.

In addition, in the sealing plate of Claim 2, since it is comprised so that the recessed part may be formed in the area | region containing the groove | channel and bulge part of the metal plate surface, and the said groove | channel and bulge part are formed in the bottom face of this recessed part, the recessed part And by setting the metal plate thickness of a groove part suitably, the breaking pressure in the groove part of a sealing plate can be adjusted more easily.

In the sealing plate of claim 3, since the metal plate is compressed to form a groove and annealing at the same time, the breaking pressure at the groove portion of the sealing plate can be set to a low value and easily adjusted. Can be.

In the manufacturing method of the sealing plate according to claim 4, a groove is formed in the metal plate by compression processing, and at the same time, a swelling portion is formed inside the groove to swell to the surface side of the metal plate. Since a sealing plate can be manufactured only by press work, it can manufacture at low cost. In addition, since the thickness of the metal plate of the groove can be easily set, and thus the breaking pressure at the groove can be easily adjusted, the sealing plate can be manufactured at low cost.

In addition, according to the manufacturing method of claim 5, the recessed portion and the groove are formed by compression processing with respect to the metal plate, and at the same time, a swelling portion that expands to the surface side of the metal plate is formed inside the groove. And by setting the thickness of the metal plate of the groove portion appropriately sequentially, the breaking pressure in the groove portion can be adjusted more easily.

In the sealing plate manufacturing method of claim 6, the annealing treatment is performed on the metal plate in addition to the above compression processing, so that the breaking pressure can be easily adjusted, and the breaking pressure can be set to a low value. A product with a relatively stable distribution can be provided.

Claims (6)

It consists of a metal plate which closes the opening part of a sealed battery container, The groove | channel is formed in the surface of the metal plate along the outline which surrounds a predetermined area | region, and the swelling part which expands to the surface side of the said metal plate inside the groove is formed. The sealing plate of the sealed battery which consists of. The sealing plate of a sealed battery according to claim 1, wherein a recess is formed in a region including the groove and the bulge on the surface of the metal plate, and the groove and the bulge are formed at the bottom of the recess. The sealed plate of a sealed battery according to claim 1 or 2, wherein said metal plate is compressed to form said groove, said bulge portion is formed, and said metal plate is annealed. Manufacture of a sealed plate for a sealed battery, characterized in that the groove is formed by compression processing along a contour surrounding a predetermined area on the surface of the metal plate, and a swelling portion is formed inside the groove to swell to the surface side of the metal plate. Way. The first predetermined region is compressed to the metal plate to form a recess in the surface of the metal plate, and the groove is formed by compression processing along the contour surrounding the second predetermined region on the bottom surface of the recess. A swelling portion that swells toward the surface of the metal plate is formed on the inner side of the sealing plate. The method for manufacturing a sealed plate of a sealed battery according to claim 4 or 5, wherein the metal plate is annealed.