CN116508124A

CN116508124A - Power storage device and method for manufacturing power storage device

Info

Publication number: CN116508124A
Application number: CN202180073604.7A
Authority: CN
Inventors: 小林利崇; 石井咏子; 岛本秀树; 森冈良太; 林宏树
Original assignee: Panasonic Intellectual Property Management Co Ltd
Current assignee: Panasonic Intellectual Property Management Co Ltd
Priority date: 2020-10-30
Filing date: 2021-10-19
Publication date: 2023-07-28

Abstract

Disclosed is a power storage device provided with: an electric storage element (11); a case (20) having a bottom cylindrical shape, which accommodates the power storage element (11), and which has an opening (21) at one end; and a sealing body (30) for sealing the opening (21). The housing (20) is provided with: a 1 st pressing part (22) which presses the side surface of the sealing body (30) near the opening part (21) and protrudes to the inner side of the shell (20); and exhaust parts (24, 26) provided on one end side of the housing (20) than the most protruding vertex (22 a) of the 1 st pressing part (22). This makes it possible to provide an electricity storage device provided with an explosion-proof mechanism that has high operational reliability and that does not impair the air tightness.

Description

Power storage device and method for manufacturing power storage device

Technical Field

The present disclosure relates to an electric storage device and a method of manufacturing the electric storage device.

Background

Conventionally, an electric storage device (specifically, an electrolytic capacitor) is known, which includes: an electric storage element; a case having a cylindrical shape with a bottom and accommodating the power storage element; and a sealing body for sealing the opening of the case (for example, patent document 1). In the power storage device of patent document 1, a constriction for compressing the sealing body is formed near the opening in the case, and a hole or slit is provided at the position of the minimum diameter of the constriction. The hole or slit functions as an explosion-proof mechanism that discharges gas in the case when the internal pressure of the case increases.

Prior art literature

Patent literature

Patent document 1: JP-A59-40767

Disclosure of Invention

Problems to be solved by the invention

However, the position of the minimum diameter of the constriction is the most important position for the function of compressing the sealing body, that is, the function of ensuring the air tightness of the power storage device. In patent document 1, since a hole or a slit is provided at this position, there is a concern that the air tightness of the power storage device is impaired. On the other hand, if no explosion-proof mechanism is provided, if the internal pressure of the case increases, the sealing body may fly out and an electrical short may occur. Under such circumstances, an object of the present disclosure is to provide an electric storage device provided with an explosion-proof mechanism that has high operational reliability and does not impair air tightness.

Means for solving the problems

An aspect of the present disclosure relates to an electrical storage device. The power storage device is provided with: an electric storage element; a case having a bottomed tubular shape, accommodating the power storage element, and having an opening at one end; and a sealing body for sealing the opening, wherein the housing comprises: a 1 st pressing portion that presses a side surface of the sealing body in the vicinity of the opening portion and protrudes toward an inside of the case; and an exhaust part provided on the one end side of the most protruding vertex of the 1 st pressing part.

Effects of the invention

According to the present disclosure, an electricity storage device provided with an explosion-proof mechanism that has high operational reliability and does not impair the air tightness can be obtained.

The novel features of the invention are set forth in the appended claims, but both as to its organization and content, together with other objects and features of the application, may be better understood by reference to the following detailed description taken in conjunction with the accompanying drawings.

Drawings

Fig. 1 is a cross-sectional view schematically showing an example of an electric storage device according to embodiment 1 of the present disclosure, and is a view of a cross section through a through hole.

Fig. 2 is an enlarged cross-sectional view showing a main part of the power storage device according to embodiment 1 when the internal pressure of the case increases.

Fig. 3 is a cross-sectional view schematically showing an example of the power storage device according to embodiment 2 of the present disclosure, and is a view of a cross section through a slit.

Fig. 4 is an enlarged cross-sectional view showing a main part of the power storage device according to embodiment 2 when the internal pressure of the case increases.

Fig. 5 is a cross-sectional view schematically showing an example of the power storage device according to embodiment 3 of the present disclosure, and is a view taken through a cross-section of the through hole.

Fig. 6 is a side view schematically showing a case of the power storage device according to embodiment 3.

Fig. 7 is an enlarged cross-sectional view showing a main part of the power storage device according to embodiment 3 when the internal pressure of the case increases.

Fig. 8 is an enlarged cross-sectional view for explaining a punching step in the method for manufacturing the power storage device according to embodiment 3.

Detailed Description

Embodiments of a power storage device and a method for manufacturing the power storage device according to the present disclosure are described below by way of example. However, the present disclosure is not limited to the examples described below. In the following description, specific values and materials may be exemplified, but other values and materials may be applied as long as the effects of the present disclosure are obtained.

The power storage device according to the present disclosure includes: the battery includes a battery element, a case having a bottomed tubular shape that accommodates the battery element and has an opening at one end, and a sealing body that seals the opening. The housing is provided with: a 1 st pressing part, which presses the side surface of the sealing body near the opening part and protrudes to the inner side of the shell; and an exhaust part arranged at one end side of the most protruding peak of the 1 st pressing part. The exhaust portion has, for example, a through hole or a slit. A protrusion protruding inward of the case may be formed at a peripheral edge portion of the through hole. The power storage device according to the present disclosure has the following structures, for example, power storage devices A, B and C, but is not particularly limited.

(electric storage device A)

A power storage device according to an embodiment of the present disclosure (hereinafter, power storage device a) includes a power storage element, a case, and a sealing body. These will be described below.

(electric storage element)

The electric storage element includes an electrode, an electrolyte, and the like. For example, in the case where the power storage device a is an electrolytic capacitor, the power storage element includes a wound body. The wound body is formed by winding a pair of electrodes through a separator, and the pair of electrodes may be polarized electrodes, or may be one anode and the other cathode. For example, in the case where the power storage device a is a secondary battery or a lithium ion capacitor, the power storage element includes an electrode group. The electrode group is formed by winding a positive electrode and a negative electrode with a separator interposed therebetween. The power storage element may further include an electrolyte or a liquid component.

(Shell)

The case has a bottomed tubular shape, has an opening at one end, and accommodates the power storage element. The housing may be composed of, for example, a metal including aluminum, iron, nickel, or the like. The shape of the case is not particularly limited, but may be, for example, a bottomed cylinder.

(sealing body)

The sealing body seals the opening of the housing. The sealing body is made of an elastic material (for example, a material containing an elastic resin). The shape of the sealing body may correspond to the shape of the case. For example, the sealing body may be disk-shaped in the case where the case is in a bottomed cylindrical shape, and may be square-plate-shaped in the case where the case is in a bottomed square cylindrical shape.

The elastic resin is preferably a rubber component. As the rubber component, butyl rubber (IIR), nitrile rubber (NBR), ethylene propylene rubber, ethylene Propylene Diene Monomer (EPDM), chloroprene Rubber (CR), isoprene Rubber (IR), sea-paren rubber, silicone rubber, fluororubber, and the like can be used alone or in combination. Among them, butyl rubber, ethylene propylene rubber, fluororubber, and the like are preferable. The elastic material may contain, as an optional component, a filler, carbon black, a processing aid, a crosslinking aid, and the like, in addition to the elastic resin.

The case has a 1 st pressing portion and a 2 nd pressing portion in the vicinity of the opening portion, and a through hole (exhaust portion) is formed between the 1 st pressing portion and the 2 nd pressing portion.

The 1 st pressing part presses the side surface of the sealing body and protrudes to the inner side of the outer shell. The inner diameter at the most protruding apex of the 1 st pressing portion may be smaller than the outer diameter of the sealing body in the state where no load is applied. The 1 st pressing portion may be formed by, for example, grooving the opening portion to reduce a diameter.

The 2 nd pressing portion is disposed on one end side of the case, that is, on the opening side of the 1 st pressing portion, and presses the edge portion of the sealing body toward the inside of the case. The 2 nd pressing portion may be formed by, for example, hemming a part of the most end side of the opening.

The through hole is provided on one end side of the case, that is, on the opening side of the most protruding apex of the 1 st pressing portion. The through hole may communicate the inside and the outside of the case when the force acting from the sealing body to the 1 st pressing portion is lower than a predetermined value due to an increase in the internal pressure of the case. The through hole may be provided only on the one end side of the case above the apex of the 1 st pressing portion. The through holes may be provided only in one or in a plurality.

Here, when the internal pressure of the case increases, the sealing body expands in the axial direction of the case and outwardly of the case. When this expansion in the axial direction occurs, the region of the sealing body in contact with the 1 st pressing portion is displaced in a direction away from the 1 st pressing portion, and therefore the force (elastic repulsive force against compression) acting from the sealing body to the 1 st pressing portion is weakened. If the urging force decreases below a predetermined value, the gas in the case passes between the sealing body and the 1 st pressing portion. By discharging the gas from the inside of the case to the outside of the case through the through-hole, the internal pressure of the power storage device a is reduced, and safety can be ensured.

Unlike the hole or slit of the power storage device of patent document 1, the through hole of the power storage device a of the present disclosure is provided not at the apex of the 1 st pressing portion but at one end side of the case, that is, at the opening side. In other words, the through hole is not provided at the vertex of the 1 st pressing portion, which is a position important in ensuring the air tightness of the power storage device. Therefore, there is substantially no case where the air tightness of the power storage device a is impaired by the through holes.

As described above, according to one embodiment of the present disclosure, it is possible to obtain the power storage device a provided with the explosion-proof mechanism that is highly reliable in operation and that does not damage the air tightness. Further, according to an embodiment of the present disclosure, by operating the explosion-proof mechanism, it is possible to prevent unexpected breakage of the power storage device a such as scattering of the sealing body.

The through hole may be disposed at a position closer to the upper surface of the sealing body than an intermediate point between the upper surface of the sealing body and the most protruding vertex of the 1 st pressing portion in the axial direction of the housing. According to this configuration, the through hole is provided sufficiently far from the apex of the 1 st pressing portion. In other words, there is no through hole at and near the vertex of the 1 st pressing portion. Therefore, it can be further difficult to damage the air tightness of the power storage device a.

The through-hole may be circular or elliptical. According to this structure, the stress is prevented from being locally concentrated on the edge portion of the through hole when the internal pressure of the case increases. Therefore, damage to the case starting from the through hole is less likely to occur.

The through hole may be polygonal. According to this structure, the through-holes are formed by the polygonal needles or the like, so that the formation of the through-holes is facilitated. Examples of the polygon include, but are not limited to, a triangle and a quadrangle.

(electric storage device B)

A power storage device according to another embodiment of the present disclosure (hereinafter, power storage device B) includes a power storage element, a case, and a sealing body. These will be described below.

(electric storage element)

The power storage element may be the same as the power storage element of the power storage device a.

(Shell)

The case may be the same as the case of the power storage device a.

(sealing body)

The sealing body may be the same as the sealing body of the power storage device a.

The opening of the case has a 1 st pressing portion and a slit (exhaust portion).

The 1 st pressing portion presses the side surface of the sealing body near the opening portion and protrudes toward the inside of the case. The inner diameter at the most protruding apex of the 1 st pressing portion may be smaller than the outer diameter of the sealing body in the state where no load is applied. The 1 st pressing portion may be formed by, for example, grooving the opening portion to reduce a diameter.

The slit is provided on one end side of the case, that is, on the opening side of the case, with respect to the most protruding apex of the 1 st pressing portion. The slit may allow the inside and outside of the case to communicate when the internal pressure of the case increases and the force applied from the sealing body to the 1 st pressing portion is lower than a predetermined value. The slit may be provided only on the one end side of the case above the apex of the 1 st pressing portion. The slit may be provided only one, or may be provided in plurality.

Here, when the internal pressure of the case increases, the sealing body expands in the axial direction of the case and outwardly of the case. When this expansion in the axial direction occurs, the region of the sealing body in contact with the 1 st pressing portion is displaced in a direction away from the 1 st pressing portion, and therefore the force (elastic repulsive force against compression) acting from the sealing body to the 1 st pressing portion is weakened. If the urging force decreases below a predetermined value, the gas in the case passes between the sealing body and the 1 st pressing portion. By discharging the gas from the inside of the case to the outside of the case through the slit, the internal pressure of power storage device B is reduced, and safety can be ensured.

Unlike the hole or slit of the power storage device of patent document 1, the slit of the power storage device B of the present disclosure is not provided at the apex of the 1 st pressing portion, but is provided on one end side of the case, that is, on the opening side, of the case. In other words, the slit is not provided at the vertex of the 1 st pressing portion, which is an important position in ensuring the air tightness of the power storage device. Therefore, there is substantially no case where the air tightness of power storage device B is impaired by the slit.

As described above, according to another embodiment of the present disclosure, it is possible to obtain the power storage device B provided with the explosion-proof mechanism that is highly reliable in operation and that does not damage the air tightness. Further, according to another embodiment of the present disclosure, by operating the explosion-proof mechanism, it is possible to prevent unexpected breakage of the power storage device B such as scattering of the sealing body or the like.

The slit may not be disposed at the apex of the 1 st pressing portion. The slit may not be disposed in the 1 st pressing portion.

The sealing body may contain an elastomer containing rubber as a main component. The rubber may constitute 50 mass% or more of the elastomer.

The case may further include a 2 nd pressing portion for pressing the upper surface of the sealing body in the vicinity of the opening. This can further improve the air tightness of power storage device B.

The slit may extend to one end of the housing. This allows the slit to be easily formed.

The tip of the slit may be located closer to the end face of the sealing body than the intermediate point between the end face (upper face) of the sealing body facing the outside of the housing and the apex of the 1 st pressing portion in the axial direction of the housing. According to this structure, the tip of the slit is provided sufficiently far from the apex of the 1 st pressing portion. In other words, there is no slit at and near the apex of the 1 st pressing portion. Therefore, it can be further difficult to damage the air tightness of power storage device B.

(electric storage device C)

A power storage device (hereinafter, power storage device C) according to still another embodiment of the present disclosure includes a power storage element, a case, and a sealing body. These will be described below.

(electric storage element)

(Shell)

The case may be the same as the case of the power storage device a.

(sealing body)

The 1 st pressing part presses the side surface of the sealing body and protrudes to the inner side of the shell. The inner diameter at the most protruding apex of the 1 st pressing portion may be smaller than the outer diameter of the sealing body in the state where no load is applied. The 1 st pressing portion may be formed by, for example, grooving the opening portion to reduce a diameter.

Here, when the internal pressure of the case increases, the sealing body expands in the axial direction of the case and outwardly of the case. When this expansion in the axial direction occurs, the region of the sealing body in contact with the 1 st pressing portion is displaced in a direction away from the 1 st pressing portion, and therefore the force (elastic repulsive force against compression) acting from the sealing body to the 1 st pressing portion is weakened. If the urging force decreases below a predetermined value, the gas in the case passes between the sealing body and the 1 st pressing portion. By discharging the gas from the inside of the case to the outside of the case through the through-hole, the internal pressure of the power storage device C is reduced, and safety can be ensured.

Unlike the hole or slit of the power storage device of patent document 1, the through hole of the power storage device C of the present disclosure is not provided at the apex of the 1 st pressing portion, but is provided on one end side of the case, that is, on the opening side. In other words, the through hole is not provided at the vertex of the 1 st pressing portion, which is an important position in ensuring the air tightness of the power storage device. Therefore, there is substantially no case where the air tightness of the power storage device C is impaired by the through hole.

Further, the power storage device C of the present disclosure forms a protrusion protruding toward the inside of the case at the peripheral edge portion of the through hole. The presence of the protrusion prevents the through hole from being blocked by the sealing body. That is, even if the sealing body is deformed and approaches the through hole, the through hole is prevented from being completely blocked by the abutment of the protrusion with the side surface of the sealing body. In addition, the protruding ends of the protrusions are not continuous throughout the entire circumference of the through hole. Thus, even in a state where the sealing body is in contact with the protrusion, communication between the inside and the outside of the case through the through hole can be ensured. The through hole may be a polygon (triangle, quadrangle, or the like), and the protrusion may be formed along each side of the polygon. The length of the protrusion may be, for example, 30% or more of the maximum diameter of the through hole.

(method for manufacturing electric storage device C)

The method for manufacturing the power storage device C according to the present disclosure includes a housing step, a sealing preparation step, a sealing completion step, and a punching step. These will be described below. The accommodating step and the sealing preparation step may be performed simultaneously.

In the housing step, the power storage element is housed in the case. For example, when the power storage device C is an electrolytic capacitor, the wound body including the power storage element is housed in the case such that the axial direction thereof substantially coincides with the axial direction of the case.

In the seal preparation step, a seal body is disposed in the opening of the case. The sealing body may be configured to contact the inner surface of the case or may be configured not to contact the inner surface of the case.

In the sealing completion step, the 1 st pressing portion and the 2 nd pressing portion are formed, thereby sealing the opening of the case. The 1 st pressing portion may be formed by, for example, grooving the opening portion to reduce a diameter. The 2 nd pressing portion may be formed by, for example, hemming a part of the opening portion. The 1 st pressing portion and the 2 nd pressing portion may be formed in the order described above, or may be formed substantially simultaneously. Alternatively, the formation of the 2 nd pressing portion may be started from the middle of the formation of the 1 st pressing portion.

In the punching step, after the sealing is completed, a through hole and a protrusion are formed between the 1 st pressing portion and the 2 nd pressing portion in the case. In the punching step, the through hole may be formed by piercing the casing with the tip end of a sharp tool (e.g., a needle). The tip of the tool may have a polygonal pyramid shape. The tip of the tool is in a polygonal pyramid shape (triangular pyramid shape, quadrangular pyramid shape, etc.), so that the projection can be stably formed.

As described above, according to the present disclosure, it is possible to obtain the power storage device C having the explosion-proof mechanism with high operation reliability without damaging the air tightness, and the manufacturing method thereof. Further, according to the present disclosure, by operating the explosion-proof mechanism, unexpected breakage of the power storage device C such as scattering of the sealing body can be prevented.

An example of the power storage device and the method of manufacturing the power storage device according to the present disclosure will be specifically described below with reference to the drawings. The components and steps described above can be applied to the components and steps of the power storage device and the method for manufacturing the power storage device, which are described below. The constituent elements and steps of the power storage device and the method for manufacturing the power storage device of one example described below can be modified based on the above description. The matters described below can also be applied to the above-described embodiments. The components and steps of the power storage device and the method of manufacturing the power storage device according to the present disclosure, which are unnecessary in the power storage device and the method of manufacturing the power storage device, among the components and steps of the power storage device and the method of manufacturing the power storage device, which are one example described below, may be omitted. The drawings shown below are schematic and do not accurately reflect the shape and number of actual members.

Embodiment 1

Embodiment 1 of the present disclosure will be described. As shown in fig. 1, the power storage device 10 of the present embodiment is configured as an electrolytic capacitor, and includes a power storage element 11, a case 20, and a sealing member 30.

The power storage element 11 includes a wound body. The wound body is formed by winding an anode foil and a cathode foil with a separator interposed therebetween. The anode foil and the cathode foil are connected to one end of each of the lead tabs 12A and 12B. The winding body is configured to wind the lead tabs 12A and 12B in at the same time. The leads 13A and 13B are connected to the other ends of the lead tabs 12A and 12B, respectively.

The case 20 has a bottomed tubular shape, has an opening 21 at one end, and accommodates the power storage element 11. The case 20 of the present embodiment is made of aluminum, but is not limited thereto. The case 20 of the present embodiment is a bottomed cylinder, but is not limited thereto. The axial length of the housing 20 may be, for example, 60 to 80mm in a state before the 1 st pressing portion 22 and the 2 nd pressing portion 23 described later are formed. The outer diameter of the housing 20 may be, for example, 16 to 20mm.

The sealing body 30 seals the opening 21 of the case 20. The sealing body 30 of the present embodiment is disk-shaped, but is not limited thereto. The thickness of the sealing body 30 (the length of the casing 20 in the axial direction) may be, for example, 3 to 7mm. The sealing body 30 may contain an elastomer mainly composed of rubber. The rubber may constitute 50 mass% or more of the elastomer.

The opening 21 of the case 20 has a 1 st pressing portion 22 and a 2 nd pressing portion 23 in the vicinity of the opening 21, and a through hole 24 is formed between the 2 nd pressing portion 23 and the 1 st pressing portion 22. The through hole 24 is an example of an exhaust portion.

The 1 st pressing portion 22 presses the side surface of the sealing body 30 and protrudes inward of the case 20. The inside diameter at the apex 22a of the 1 st pressing portion 22 is smaller than the outside diameter of the sealing body 30 in the state where no load is applied. The 1 st pressing portion 22 of the present embodiment is formed by grooving processing in which a part of the opening 21 is reduced in diameter, but is not limited thereto.

The 2 nd pressing portion 23 is disposed closer to one end side (i.e., the opening side) of the case 20 than the 1 st pressing portion 22, and presses the edge portion of the sealing body 30. In other words, the 2 nd pressing portion 23 presses the upper surface 30a of the sealing body 30 in the vicinity of the opening 21. The 2 nd pressing portion 23 of the present embodiment is formed by hemming a part of the opening 21, but is not limited thereto.

The through hole 24 is provided on one end side (i.e., the opening side) of the case 20 with respect to the apex 22a of the 1 st pressing portion 22. In other words, the through hole 24 is not disposed at the apex 22a of the 1 st pressing portion 22. The through hole 24 is disposed closer to the end face 30a of the sealing body 30 than an intermediate point MP between an end face (upper face) 30a of the sealing body 30 facing the outside of the housing 20 and the apex 22a of the 1 st pressing portion 22 in the axial direction of the housing 20. The portion of the opening 21 on the opening side of the apex 22a of the 1 st pressing portion 22 may be partially not in contact with the sealing body 30. That is, a gap may be formed between the inner surface of the opening 21 and the side surface of the sealing body 30 on the opening side of the apex 22a of the 1 st pressing portion 22. The through hole 24 of the present embodiment is circular, but is not limited thereto. For example, the through hole 24 may have a polygonal shape.

The distance from one end of the case 20 to the center of the through hole 24 (the distance in the direction parallel to the axial direction of the case 20) before the formation of the 2 nd pressing portion 23 may be, for example, 0.25×d to 0.9×d, assuming D as the distance from one end of the case 20 to the apex 22a of the 1 st pressing portion 22 before the formation of the 2 nd pressing portion 23. The distance D in the present embodiment may be, for example, 2 to 8mm. The diameter of the through hole 24 may be, for example, 0.5 to 2mm.

When the force acting from the sealing body 30 to the 1 st pressing portion 22 is lower than the predetermined value due to the increase of the internal pressure of the casing 20, the through hole 24 communicates the inside and the outside of the casing 20. On the other hand, when the urging force is equal to or greater than the predetermined value, the through hole 24 does not allow the inside and outside of the housing 20 to communicate.

As shown in fig. 2, when the internal pressure of the case 20 increases, the sealing body 30 expands outside the case 20 in the axial direction of the case 20. When this expansion in the axial direction occurs, the region of the sealing body 30 in contact with the 1 st pressing portion 22 is displaced in a direction away from the 1 st pressing portion 22 (i.e., radially inward), and therefore the force (elastic repulsive force against compression) acting from the sealing body 30 to the 1 st pressing portion 22 is reduced. When the urging force decreases below the predetermined value, the gas in the case 20 passes between the sealing body 30 and the 1 st pressing portion 22. By discharging the gas from inside the case 20 to outside the case 20 through the through-hole 24, the safety of the power storage device 10 can be ensured.

Embodiment 2

Embodiment 2 of the present disclosure will be described. As shown in fig. 3, the power storage device 10 of the present embodiment is configured as an electrolytic capacitor, and includes a power storage element 11, a case 20, and a sealing member 30.

The power storage element 11 may be the same as in embodiment 1.

The case 20 may be similar to embodiment 1.

The sealing body 30 may be similar to embodiment 1.

The opening 21 of the housing 20 includes a 1 st pressing portion 22, a 2 nd pressing portion 23, and a slit 26. The slit 26 is an example of an exhaust portion.

The 1 st pressing portion 22 presses the side surface of the sealing body 30 near the opening 21 and protrudes toward the inside of the case 20. The inside diameter at the apex 22a of the 1 st pressing portion 22 is smaller than the outside diameter of the sealing body 30 in the state where no load is applied. The 1 st pressing portion 22 of the present embodiment is formed by grooving processing in which a part of the opening 21 is reduced in diameter, but is not limited thereto.

The slit 26 is provided on one end side (i.e., the opening side) of the housing 20 than the apex 22a of the 1 st pressing portion 22. In other words, the slit 26 is not disposed at the apex 22a of the 1 st pressing portion 22. The slit 26 is formed from one end of the housing 20 to a predetermined position between one end of the housing 20 and the apex 22a of the 1 st pressing portion 22. The tip of the slit 26 is located closer to the end face 30a of the sealing body 30 than the intermediate point MP between the end face (upper face) 30a of the sealing body 30 facing the outside of the housing 20 and the apex 22a of the 1 st pressing portion 22 in the axial direction of the housing 20. The portion of the opening 21 closer to the opening side than the apex 22a of the 1 st pressing portion 22 may be partially not in contact with the sealing body 30. That is, a gap may not exist between the inner surface of the opening 21 and the side surface of the sealing body 30 on the opening side of the apex 22a of the 1 st pressing portion 22.

Assuming that the distance from one end of the case 20 to the apex 22a of the 1 st pressing portion 22 before the 2 nd pressing portion 23 is formed is D, the length of the slit 26 (the length in the direction parallel to the axial direction of the case 20) may be, for example, 0.25×d to 0.9×d. The distance D in the present embodiment may be, for example, 2 to 8mm. The width of the slit 26 (length in the circumferential direction of the case 20) may be, for example, 0.2 to 0.5mm.

The slit 26 communicates the inside and the outside of the case 20 when the force acting from the sealing body 30 to the 1 st pressing portion 22 is lower than a predetermined value due to the increase of the internal pressure of the case 20. On the other hand, when the urging force is equal to or greater than the predetermined value, the slit 26 does not allow the inside and outside of the housing 20 to communicate.

Here, as shown in fig. 4, when the internal pressure of the case 20 increases, the sealing body 30 expands outside the case 20 in the axial direction of the case 20. When this expansion in the axial direction occurs, the region of the sealing body 30 in contact with the 1 st pressing portion 22 is displaced in a direction away from the 1 st pressing portion 22 (i.e., radially inward), and therefore the force (elastic repulsive force against compression) acting from the sealing body 30 to the 1 st pressing portion 22 is reduced. When the urging force decreases below the predetermined value, the gas in the case 20 passes between the sealing body 30 and the 1 st pressing portion 22. By discharging the gas from inside the case 20 to outside the case 20 through the slit 26, the safety of the power storage device 10 can be ensured.

Embodiment 3

Embodiment 3 of the present disclosure will be described. As shown in fig. 5 and 6, the power storage device 10 of the present embodiment is configured as an electrolytic capacitor, and includes a power storage element 11, a case 20, and a sealing member 30.

The power storage element 11 may be the same as in embodiment 1.

The case 20 may be similar to embodiment 1.

The sealing body 30 may be similar to embodiment 1.

The through hole 24 is provided on one end side (i.e., the opening side) of the case 20 with respect to the apex 22a of the 1 st pressing portion 22. In other words, the through hole 24 is not disposed at the apex 22a of the 1 st pressing portion 22. The portion of the opening 21 on the opening side of the apex 22a of the 1 st pressing portion 22 may be partially not in contact with the sealing body 30. That is, a gap may be formed between the inner surface of the opening 21 and the side surface of the sealing body 30 on the opening side of the apex 22a of the 1 st pressing portion 22. The through-hole 24 of the present embodiment is a quadrangular shape, but is not limited thereto. For example, the through hole 24 may have a circular shape or a polygonal shape other than a quadrangular shape.

The distance from one end of the case 20 to the center of the through hole 24 (the distance in the direction parallel to the axial direction of the case 20) before the formation of the 2 nd pressing portion 23 may be, for example, 0.25×d to 0.9×d, assuming D as the distance from one end of the case 20 to the apex 22a of the 1 st pressing portion 22 before the formation of the 2 nd pressing portion 23. The distance D in the present embodiment may be, for example, 2 to 8mm. The diameter of the through hole 24 (the diameter of the circumscribed circle of the through hole 24) may be, for example, 0.5 to 2mm.

Here, as shown in fig. 7, when the internal pressure of the case 20 increases, the sealing body 30 expands outside the case 20 in the axial direction of the case 20. When this expansion in the axial direction occurs, the region of the sealing body 30 in contact with the 1 st pressing portion 22 is displaced in a direction away from the 1 st pressing portion 22 (i.e., radially inward), and therefore the force (elastic repulsive force against compression) acting from the sealing body 30 to the 1 st pressing portion 22 is reduced. When the urging force decreases below the predetermined value, the gas in the case 20 passes between the sealing body 30 and the 1 st pressing portion 22. By discharging the gas from inside the case 20 to outside the case 20 through the through-hole 24, the safety of the power storage device 10 can be ensured.

As shown in fig. 5 and 6, the power storage device 10 includes a protrusion 25 protruding inward of the case 20 at the peripheral edge of the through hole 24. In the present embodiment, 4 triangular protrusions 25 are formed along each side of the quadrangular through hole 24. Each projection 25 narrows in width from the base end toward the projection end. Therefore, the protruding ends of the protrusions 25 are not continuous throughout the entire circumference of the through hole 24. The protrusions 25 may be formed at the same time when the through hole 24 is formed in the case 20.

The presence of the protrusion 25 prevents the through hole 24 from being blocked by the sealing body 30. That is, even if the sealing body 30 is deformed and approaches the through hole 24, the protrusion 25 abuts against the side surface of the sealing body 30, so that the through hole 24 is prevented from being completely blocked (for example, see fig. 7).

(method for manufacturing electric storage device)

A method of manufacturing the above-described power storage device 10 will be described. The manufacturing method comprises a housing step, a sealing preparation step, a sealing completion step, and a perforation step.

In the housing step, the power storage element 11 is housed in the case 20. In the present embodiment, since the power storage device 10 is an electrolytic capacitor, the wound body included in the power storage element 11 is housed in the case 20 such that the axial direction thereof substantially coincides with the axial direction of the case 20.

In the seal preparation step, the sealing body 30 is disposed in the opening 21 of the case 20. The sealing body 30 may be configured to contact the inner surface of the case 20, or may be configured not to contact the inner surface of the case 20.

In the sealing completion step, the 1 st pressing portion 22 and the 2 nd pressing portion 23 are formed. The 1 st pressing portion 22 is formed by grooving the opening 21 by reducing a part thereof. The 2 nd pressing portion 23 is formed by hemming a part of the opening 21. In the present embodiment, the formation of the 1 st pressing portion 22 is started, and the formation of the 2 nd pressing portion 23 is started in the middle of the formation. With the above, the opening 21 of the case 20 is sealed.

The punching process is performed after the sealing completion process. In the punching step, a through hole 24 and a protrusion 25 are formed between the 1 st pressing portion 22 and the 2 nd pressing portion 23 in the case 20. In the punching step of the present embodiment, as shown in fig. 8, the through hole 24 is formed by piercing the housing 20 with the tip end portion of the needle 40. The tip of the needle 40 has a quadrangular pyramid shape. Needle 40 is one example of a sharp tool.

Examples

The relationship between the position of the through hole 24 and the operating pressure of the explosion-proof mechanism was measured for the power storage devices 10 of examples 1 to 5 and comparative example 1 shown below. Here, the operating pressure of the explosion-proof mechanism means the internal pressure of the casing 20 when the inside and outside of the casing 20 communicate through the through hole 24 when the internal pressure of the casing 20 increases. The power storage device 10 of examples 1 to 5 corresponds to embodiment 1 described above.

Example 1

The outer diameter of the aluminum case 20 was set to 18mm, the axial length of the case 20 before the 1 st pressing portion 22 and the 2 nd pressing portion 23 were formed was set to 70mm, and the distance from one end of the case 20 to the apex 22a of the 1 st pressing portion 22 before the 2 nd pressing portion 23 was formed was set to 4.5mm. The thickness of the sealing body 30 made of butyl rubber was set to 5mm, and the outer diameter of the sealing body 30 before compression was set to 17.1mm. The diameter of the through hole 24 was set to 1mm, and the distance from one end of the housing 20 to the center of the through hole 24 before the 2 nd pressing portion 23 was formed (hereinafter, simply referred to as "distance to the through hole 24") was set to 1.1mm. The action pressure of the explosion-proof mechanism is 2.06MPa.

Example 2

The distance to the through hole 24 was 1.73mm, and the configuration was the same as in example 1. The operating pressure of the explosion-proof mechanism is 2.07MPa.

Example 3

The configuration was the same as in example 1 except that the distance to the through hole 24 was set to 2.22 mm. The operating pressure of the explosion-proof mechanism is 2.04MPa.

Example 4

The configuration was the same as in example 1 except that the distance to the through hole 24 was set to 2.59 mm. The operating pressure of the explosion-proof mechanism is 2.04MPa.

Example 5

The configuration was the same as in example 1 except that the distance to the through hole 24 was 3.33 mm. The action pressure of the explosion-proof mechanism is 2.06MPa.

Comparative example 1

The configuration was the same as in example 1 except that the distance to the through hole 24 was set to 4.26 mm. In other words, a part of the through hole 24 is located on the other end side of the case 20 than the apex 22a of the 1 st pressing portion 22. The operating pressure of the explosion-proof mechanism is 1.12MPa.

As described above, between examples 1 to 5 and comparative example 1, a difference of about 2 times was observed in the operating pressure of the explosion-proof mechanism. In examples 1 to 5, the operating pressure of the explosion-proof mechanism was substantially constant. As long as the desired operation is obtained, it is preferable that the operating pressure of the explosion-proof mechanism is high, and it can be said that examples 1 to 5 exhibit advantages.

Further, the relationship between the length of the slit 26 and the operating pressure of the explosion-proof mechanism was measured for the power storage devices 10 of examples 6 to 9 and comparative example 2 shown below. Here, the operating pressure of the explosion-proof mechanism means the internal pressure of the casing 20 when the inside and outside of the casing 20 communicate through the slit 26 when the internal pressure of the casing 20 increases. The power storage device 10 of examples 6 to 9 corresponds to embodiment 2 described above.

Example 6

The outer diameter of the aluminum case 20 was set to 18mm, the axial length of the case 20 before the 1 st pressing portion 22 and the 2 nd pressing portion 23 were formed was set to 70mm, and the distance from one end of the case 20 to the apex 22a of the 1 st pressing portion 22 before the 2 nd pressing portion 23 was formed was set to 4.5mm. The thickness of the sealing body 30 made of butyl rubber was set to 5mm, and the outer diameter of the sealing body 30 before compression was set to 17.1mm. The width of the slit 26 was set to 0.3mm, and the length of the slit 26 was set to 1mm. The action pressure of the explosion-proof mechanism is 1.98MPa.

Example 7

The configuration was the same as in example 6 except that the length of the slit 26 was set to 2mm. The operating pressure of the explosion-proof mechanism is 1.87MPa.

Example 8

The configuration was the same as in example 6 except that the length of the slit 26 was 3 mm. The operating pressure of the explosion-proof mechanism is 1.66MPa.

Example 9

The configuration was the same as in example 6 except that the length of the slit 26 was 4 mm. The operating pressure of the explosion-proof mechanism is 1.58MPa.

Comparative example 2

The configuration was the same as in example 6 except that the length of the slit 26 was set to 5mm. The operating pressure of the explosion-proof mechanism is 0.15MPa.

As described above, between examples 6 to 9 and comparative example 2, a difference of about 1 order of magnitude was observed in the operating pressure of the explosion-proof mechanism. Examples 6 to 9 are advantageous in that the operating pressure of the explosion-proof mechanism is preferably high, as long as the desired operation can be obtained.

The present invention has been described with respect to preferred embodiments at the present time, but such disclosure is not to be interpreted in a limiting sense. Various modifications and alterations will become apparent to those skilled in the art in view of the foregoing disclosure. It is therefore intended that the appended claims be interpreted as covering all alterations and modifications as fall within the true spirit and scope of the invention.

Industrial applicability

The present disclosure can be used for an electric storage device and a method for manufacturing the electric storage device.

Symbol description-

10: power storage device

11: electric storage element

12a,12b: lead tab

13a,13b: lead wire

20: shell body

21: an opening part

22: 1 st pressing part

22a: vertex point

23: 2 nd pressing part

24: through hole (exhaust part)

25: protrusions

26: slit (exhaust part)

30: sealing body

30a: end face (Upper surface)

40: needle (tool)

MP: an intermediate point.

Claims

1. A power storage device is provided with:

an electric storage element;

a case having a bottomed tubular shape, accommodating the power storage element, and having an opening at one end; and

a sealing body for sealing the opening,

the housing is provided with:

a 1 st pressing portion that presses a side surface of the sealing body in the vicinity of the opening portion and protrudes toward an inside of the case; and

and an exhaust part provided on the one end side of the most protruding vertex of the 1 st pressing part.

2. The power storage apparatus according to claim 1, wherein,

the exhaust part has a through hole.

3. The power storage apparatus according to claim 2, wherein,

the through hole is disposed at a position closer to the upper surface of the sealing body than an intermediate point between the upper surface of the sealing body and a most protruding vertex of the 1 st pressing portion in an axial direction of the housing.

4. The power storage device according to claim 2 or 3, wherein,

the through hole is circular or elliptical.

5. The power storage device according to claim 2 or 3, wherein,

the through hole is polygonal.

6. The power storage device according to any one of claims 1 to 5, wherein,

the case further includes a 2 nd pressing portion for pressing the upper surface of the sealing body in the vicinity of the opening.

7. The power storage apparatus according to claim 6, wherein,

the exhaust portion is provided between the 1 st pressing portion and the 2 nd pressing portion in the housing.

8. The power storage apparatus according to claim 1, wherein,

the exhaust part has a slit.

9. The power storage apparatus according to claim 8, wherein,

the slit is not disposed at the vertex.

10. The electrical storage device according to claim 8 or 9, wherein,

the sealing body comprises an elastomer containing rubber as a main component.

11. The electrical storage device according to any one of claims 8 to 10, wherein,

12. The electrical storage device according to any one of claims 8 to 11, wherein,

the slit extends to the one end of the housing.

13. The power storage apparatus according to claim 1, wherein,

the exhaust part is provided with a through hole,

a protrusion protruding inward of the housing is formed at a peripheral edge portion of the through hole.

14. The power storage apparatus according to claim 13, wherein,

the through-hole is a polygonal shape,

the protrusions are formed along sides of the polygon.

15. The power storage device according to claim 13 or 14, wherein,

16. The power storage apparatus according to claim 15, wherein,

17. A method for manufacturing an electrical storage device according to any one of claims 13 to 16,

the method for manufacturing the power storage device includes: and a piercing step of piercing the casing with a sharp tool tip to form the through hole.

18. The method for manufacturing an electrical storage device according to claim 17, wherein,

the front end of the tool is in a polygonal pyramid shape.

19. A method for manufacturing the power storage device according to claim 15 or 16, comprising:

a housing step of housing the power storage element in the case;

a seal preparation step of disposing the seal body at the opening;

a sealing completion step of forming the 1 st pressing portion and the 2 nd pressing portion; and

and a punching step of forming the through hole and the protrusion between the 1 st pressing portion and the 2 nd pressing portion in the case after the sealing completion step.