Energy storage device

Abstract

To obtain an energy storage device that can prevent the opening of the safety valve from being obstructed. [Solution] The energy storage device 10 comprises a cylindrical housing 12 that houses an electrode body inside and has a central axis in a first direction, a lid 13 fixed to one end of the housing 12 in the first direction by a crimped portion F formed by crimping the housing 12, a safety valve 22 positioned to overlap with the central axis when viewed from the first direction, an annular partition wall 13E provided radially outward from the safety valve 22 and radially inward from the crimped portion F, extending toward one end of the lid 13, and a sealing member positioned radially outward from the partition wall 13E, toward the other end of the housing 12 toward the end of the one end, and sealing the crimped portion.

Description

Technical Field

[0001] The present disclosure relates to a power storage device.

Background Art

[0002] Patent Document 1 discloses a structure in which a sealant is filled in a gap between an electrode lid and a battery case in a caulking fixing portion of a cylindrical power storage cell to improve the sealing property.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a power storage cell provided with a safety valve, there is a risk of inhibiting the opening of the safety valve depending on the filling condition of the sealant, for example, when the sealant is provided in the vicinity of the safety valve.

[0005] In consideration of the above facts, an object of the present invention is to provide a power storage device capable of preventing the opening of the safety valve from being inhibited.

Means for Solving the Problems

[0006] The energy storage device according to claim 1 comprises: a cylindrical housing having a central axis in a first direction and housing an electrode body inside; a lid fixed to one end of the housing in the first direction by a crimped portion formed by crimping the housing; a safety valve positioned to overlap the central axis when viewed from the first direction; an annular partition wall provided radially outward from the safety valve and radially inward from the crimped portion, extending toward the one end; and a sealing member positioned radially outward from the partition wall, toward the other end of the housing toward the one end, and sealing the crimped portion.

[0007] The energy storage device according to claim 1 comprises an annular partition wall extending radially outward from the safety valve and radially inward from the crimped portion toward one end, and a sealing member positioned radially outward from the partition wall toward the other end of the housing toward the one end, and sealing the crimped portion. Therefore, the partition wall provided radially between the sealing member and the safety valve suppresses the movement of the sealing member toward the safety valve, thereby preventing obstruction of the opening of the safety valve.

[0008] The energy storage device according to claim 2, in the configuration described in claim 1, wherein the cover is provided with an annular recess that is spaced radially apart from the safety valve when viewed from the first direction and has one end in the first direction open, and the partition wall is composed of the inner wall radially inside the recess.

[0009] The energy storage device according to claim 2 of the present invention is provided with an annular recess that is positioned radially apart from the safety valve when viewed from a first direction, and whose one end in the first direction is open. Therefore, the recess prevents the sealing member from moving toward the safety valve, thus preventing obstruction of the opening of the safety valve.

[0010] The energy storage device according to claim 3, in the configuration described in claim 1 or claim 2, wherein, when viewed from a direction perpendicular to the first direction, the crimped portion has one radially outer end that is spaced further from the cover than the radially inner end.

[0011] In the energy storage device according to claim 3, since one radially outer end of the crimped portion is spaced further from the cover than one radially inner end, it is possible to suppress a decrease in the sealing performance of the crimped portion due to the movement of the sealing member radially outward.

[0012] The energy storage device according to claim 4, in the configuration described in claim 3, wherein the crimped portion is spaced apart from the cover as viewed from a direction perpendicular to the first direction, from one end on the radially inner side toward one end on the radially outer side.

[0013] In the energy storage device according to claim 4, the crimped portion is spaced further apart from the cover as it moves from one radially inner end to one radially outer end, making it easier for the sealing member to move from the radially outer to the radially inner side. This makes it possible to further suppress the decrease in the sealing performance of the crimped portion due to the movement of the sealing member radially outward.

[0014] The energy storage device according to claim 5, in the configuration described in any one of claims 1 to 4, the lid has an inclination in the radial direction that moves away from the housing from the periphery toward the partition wall.

[0015] In the energy storage device according to claim 5, the lid has a slope in the radial direction that moves away from the housing from the periphery toward the partition wall, so that the sealing member can easily move along the slope and accumulate on the crimped side. This makes it possible to further suppress the decrease in sealing performance at the crimped portion.

[0016] The energy storage device according to claim 6, in the configuration according to any one of claims 1 to 5, the housing comprises an annular second partition wall extending from the crimped portion toward the one end, and the sealing member is positioned on the other end side of the second partition wall rather than the one end side.

[0017] In the energy storage device according to claim 6, the housing is provided with an annular second partition wall extending from the crimped portion toward one end, and the sealing member is positioned on the other end side of the second partition wall rather than the end on the one end side, so that the second partition wall can suppress the movement of the sealing member outward from the crimped portion.

[0018] The energy storage device according to claim 7, in the configuration described in claim 6, is further provided with a third partition wall extending radially inward at the end of the second partition wall on the one end side, and the sealing member is positioned on the other end side of the third partition wall.

[0019] In the energy storage device according to claim 7, a third partition wall is provided at one end of the second partition wall, extending radially inward, and the sealing member is positioned on the other end side of the third partition wall, so that the movement of the sealing member toward the one end side can be suppressed by the third partition wall.

[0020] The energy storage device according to claim 8, in the configuration according to any one of claims 1 to 7, is provided with a fourth partition wall extending radially outward at the end of the partition wall on the one end side, and the sealing member is positioned on the other end side of the fourth partition wall.

[0021] In the energy storage device according to claim 8, a fourth partition wall is provided at one end of the partition wall, extending radially outward, and the sealing member is positioned on the other end side of the fourth partition wall, so that the movement of the sealing member toward the safety valve side can be further suppressed by the fourth partition wall.

[0022] The energy storage device according to claim 9, in the configuration described in claim 8, which references claim 7, wherein the third partition and the fourth partition are offset in the first direction, and when viewed from the first direction, a portion of the third partition and the fourth partition overlap.

[0023] In the power storage device according to the present invention described in claim 9, the third partition wall and the fourth partition wall are displaced in the first direction, and a part of the third partition wall and the fourth partition wall overlap when viewed from the first direction. Therefore, the third partition wall and the fourth partition wall can suppress the seal member from moving to the one-end side.

[0024] The power storage device according to the present invention described in claim 10 is the configuration described in claim 8 that cites claim 7, wherein the third partition wall and the fourth partition wall are joined at their radial end portions when viewed from the first direction.

[0025] In the power storage device according to the present invention described in claim 10, the third partition wall and the fourth partition wall are joined at their radial end portions when viewed from the first direction. Therefore, the third partition wall and the fourth partition wall can further suppress the seal member from moving to the one-end side.

Advantages of the Invention

[0026] As described above, the power storage device according to the present invention has an excellent effect of being able to prevent the opening of the safety valve from being inhibited.

Brief Description of the Drawings

[0027] [Figure 1] It is a schematic cross-sectional view showing an example of the power storage device according to the first embodiment of the present disclosure. [Figure 2] It is an enlarged cross-sectional view of the inside of the A frame shown by the dashed-dotted line in the power storage device of FIG. 1. [Figure 3] It is an enlarged cross-sectional view of the inside of the C frame shown by the dashed-dotted line in the power storage device of FIG. 2. [Figure 4] It is a schematic top view of the power storage device of FIG. 1 as viewed from the lid side. [Figure 5] It is an enlarged cross-sectional view corresponding to FIG. 3 showing a modified example of the power storage device according to the first embodiment. [Figure 6] It is an enlarged cross-sectional view corresponding to FIG. 2 of the power storage device according to the second embodiment of the present disclosure. [Figure 7] It is an enlarged cross-sectional view of the inside of the C frame shown by the dashed-dotted line in the power storage device of FIG. 6. [Figure 8] Figure 6 is a schematic top view of the energy storage device as seen from the lid side. [Figure 9] This is an enlarged cross-sectional view corresponding to Figure 2 of the energy storage device according to the third embodiment of this disclosure. [Figure 10] Figure 9 is an enlarged cross-sectional view of the area within frame C, indicated by the dashed line, of the energy storage device. [Figure 11] Figure 9 is a schematic top view of the energy storage device as seen from the lid side. [Figure 12] This is an enlarged cross-sectional view corresponding to Figure 2 of the energy storage device according to the fourth embodiment of this disclosure. [Figure 13] Figure 11 is an enlarged cross-sectional view of the area within frame C, indicated by the dashed line, of the energy storage device. [Figure 14] Figure 12 is a schematic top view of the energy storage device as seen from the lid side. [Figure 15] This is an enlarged cross-sectional view corresponding to Figure 13, which shows a modified example of the energy storage device according to the fourth embodiment. [Figure 16] This is an enlarged cross-sectional view of an energy storage device without an outer wall. [Modes for carrying out the invention]

[0028] The following describes various embodiments for implementing this disclosure with reference to the drawings. In the following, only the necessary parts for explaining the objectives of this disclosure are schematically shown, and the explanation will primarily focus on the parts necessary for explaining the relevant sections of this disclosure. Any parts omitted from the explanation will be considered to be based on prior art. Furthermore, identical or equivalent components in the drawings are denoted by the same or similar reference numerals, and redundant explanations are omitted. Additionally, if multiple identical or equivalent components are included in the drawings, reference numerals may be assigned to only some of them for clarity.

[0029] <First Embodiment> Figure 1 is a schematic cross-sectional view showing an example of a power storage device 10 according to the first embodiment of this disclosure, and Figure 2 is an enlarged cross-sectional view of the area within frame A, indicated by the dotted line, of the power storage device 10 in Figure 1. Figure 3 is an enlarged cross-sectional view of the area within frame C, indicated by the dashed line, of the power storage device 10 in Figure 2, and Figure 4 is a schematic top view of the power storage device 10 in Figure 1 as seen from the lid 13 side. The power storage device 10 according to the first embodiment is composed of a cylindrical battery as an example, as shown in Figure 1, and is used in electric bicycles, electric vehicles, etc. In the following description, the direction of arrow X shown in Figure 1 may be referred to as the width direction or lateral direction, and the direction of arrow Y (axial direction) may be referred to as the up-down direction or height direction. In this embodiment, the Y direction corresponds to the first direction, the positive side of arrow Y corresponds to one end side, and the negative side corresponds to the other end side. For convenience of explanation, the positive side of arrow Y will be referred to as the upper side and the negative side as the lower side.

[0030] The energy storage device 10 according to this embodiment can be composed of a battery containing an electrolyte, such as a lithium-ion battery. As shown in Figure 2, the energy storage device 10 includes at least an electrode body 11, a battery case 12 that houses the electrode body 11 together with the electrolyte, and a lid 13 that at least partially closes the opening of the battery case 12. In this embodiment, the energy storage device 10 is exemplified as containing an electrolyte, but the battery case 12 may not contain any liquid.

[0031] The electrode body 11 can be constructed, for example, as a wound cylindrical energy storage cell. This electrode body 11 may have a structure in which a strip-shaped positive electrode 14 and a negative electrode 15 are wound together with a strip-shaped separator 16 interposed between them. For the positive electrode 14, metals such as cobalt, nickel, manganese, or iron phosphate-based materials can be used, either alone or in combination. For the negative electrode 15, carbon-based materials or other alloys can be used. Furthermore, a porous sheet having ion permeability and insulating properties can be used for the separator 16, and materials such as polyethylene, polyolefin resins including polypropylene, or cellulose can be used.

[0032] Furthermore, the electrolyte sealed inside the energy storage device 10 can be an organic solvent such as ethylene carbonate, dimethyl carbonate, or diethyl carbonate in which lithium electrolyte salt is dissolved. The materials and shapes of each component constituting the electrode body 11, the type of electrolyte, etc., may be appropriately selected and adopted based on the intended use of the energy storage device 10.

[0033] An upper insulating plate 17 and a lower insulating plate 18 are provided at the upper and lower parts of the electrode body 11, respectively. As shown in Figures 1 and 2, the upper insulating plate 17 is provided with a positive electrode lead 19, one end of which is electrically connected to the middle portion of the positive electrode 14 in the winding direction. The upper insulating plate 17 is also provided with a through hole 17A into which the positive electrode lead 19 is inserted. The other end of the positive electrode lead 19 can be electrically connected to a terminal plate 21, which will be described later.

[0034] The battery case 12 is formed in a cylindrical shape with a central axis in the Y direction, for example, and can be made up of an outer container made of a bottomed cylindrical metal container. An opening 12A is provided at the top of the battery case 12, and this opening 12A is closed by a lid 13 after the electrode body 11 and electrolyte are inserted. Furthermore, this battery case 12 can function as a negative electrode terminal electrically connected to the negative electrode 15 by connecting a negative electrode lead (not shown) electrically connected to the end of the wound negative electrode 15 or to an appropriate location on the negative electrode 15. This battery case 12 can be manufactured by forming a bottomed cylindrical shape from a metal plate by drawing or the like.

[0035] The cover 13 can be made up of a sealing body that closes the opening 12A of the battery case 12. In this embodiment, the cover 13 is formed to have a circular recess on the lower side surrounding the central axis, and is provided with a housing portion 13A that houses the safety valve 22, which will be described later. The cover 13 is formed in a substantially circular shape when viewed from above, and as shown in Figure 2, it comprises a central portion 13B in which the housing portion 13A is formed, and an outer peripheral portion 13C that extends around the outer circumference of the central portion 13B, with its upper surface located one level lower than the central portion 13B. The outer peripheral portion 13C is provided with an annular recess 13D, which will be described later.

[0036] Furthermore, the cover 13 is equipped with a terminal plate 21 on its axial lower surface, to which the other end of the positive lead 19 is attached by welding or the like. A safety valve 22 is positioned on the central axis of the cover 13 within the housing portion 13A of the cover 13. The safety valve 22 is positioned opposite the terminal plate 21, and an insulating plate (not shown) is placed between the terminal plate 21 and the safety valve 22.

[0037] The terminal plate 21 can be made of a roughly disc-shaped plate made of metal, such as stainless steel (SUS), aluminum, or an aluminum alloy. The outer periphery of the safety valve 22 is joined to the upper surface of the outer periphery of the central hole 21A located in the center of the terminal plate 21 by welding or adhesive bonding. In addition, a plurality of vents (not shown) used to release pressure are provided at a predetermined radial distance from the safety valve 22 on the cover 13, for example, within a circle B shown by a dotted line. In this embodiment, for example, the plurality of vents are provided on the outer circumferential surface of the central part 13B of the cover 13.

[0038] The safety valve 22 is made of a roughly disc-shaped plate body that is larger in diameter than the central hole 21A of the terminal plate 21 and smaller in diameter than the inner circumferential surface of the housing 13A. Furthermore, the safety valve 22 is positioned so that its central axis coincides with the central axis of the cover 13. This safety valve 22 can be manufactured by press-forming a sheet of metal, such as stainless steel (SUS), aluminum, or aluminum alloy. If stainless steel, aluminum, or aluminum alloy is used for the safety valve 22, the material can be shared with the terminal plate 21, and joining the safety valve 22 and the terminal plate 21 by welding or other means can be facilitated. The safety valve 22 can employ a known valve structure that is pressed and inverted by the pressure when the pressure inside the battery case 12 rises, thereby preventing damage to the battery case 12.

[0039] The energy storage device 10 is sealed by crimping the edge of the lid 13, which includes the above-described configuration, to the opening 12A via the crimping portion F. Therefore, an example of the structure of the crimping portion F will be described below.

[0040] As shown in Figures 2 and 3, the crimping portion F is formed in an annular shape at one end of the battery storage device 10 in the axial direction (height direction), specifically at the opening 12A of the battery case 12, and crimps and fixes the outer circumference of the cover 13, including the terminal plate 21, with a gasket 23 in between. As an example, the crimping portion F is formed by bending the tip 12B on the axial end side of the battery case 12 at the position indicated by arrow R1, and then bending it so that the two battery cases 12 overlap at the position indicated by arrow R2, which is further to the other end than the position indicated by arrow R1. Then, by bending it further to the position indicated by arrow R3, which is even further to the other end than the position indicated by arrow R2, and at the position indicated by arrow R4, which is even further to the other end than arrow R3, it is bent into a shape that surrounds the outer circumference 13D of the cover 13, including the terminal plate 21. As described above, after bending one end of the battery case 12, the crimping portion F can be clamped and crimped from above and below by a pressing device (not shown).

[0041] In this embodiment, in the battery case 12, the upper surface of the tip portion 12B is extended radially outward, and the portion where the housing of the battery case 12 overlaps with the line D1 shown by the dashed line, on one end side (upper side), becomes the outer wall portion 12C as a second partition. In the battery case 12, the portion extending downward from the outer wall portion 12C becomes the upper outer circumference portion 12D, and the portion extending radially inward from the lower end of the upper outer circumference portion 12D becomes the bottom portion 12E. In the crimping portion F, as an example, the other end (downward) side of the outer wall portion 12C, i.e., the tip portion 12B and the bottom portion 12E, can be clamped and crimped from above and below by a pressing device (not shown). That is, the radially inward side of the upper side of the gasket 23 and the radially inward side of the tip portion 12B of the battery case 12 are pressed downward, so that the radially inward side is located axially lower than the radially outward side.

[0042] When viewed from a direction perpendicular to the vertical direction (axial direction) (X direction), the upper end of the outer wall portion 12C, which is one end on the radially outer side of the crimped portion F, is spaced further from the cover 13 than the upper surface of the radially inner tip portion 12B, which is one end on the radially inner side. In other words, the upper end of the outer wall portion 12C, which is one end on the radially outer side, is located on the one-end side (above side) than the upper surface of the radially inner tip portion 12B, which is one end on the radially inner side.

[0043] Furthermore, in this embodiment, when viewed from a direction perpendicular to the vertical direction (axial direction) (X direction), the crimped portion F has an upper end which is the radially inner end of the tip portion 12B that is spaced apart from the cover 13 as it approaches the upper end which is the radially outer end. In other words, the upper surface of the tip portion 12B has a slope that is located downward from the radially outer side towards the inner side.

[0044] The gasket 23 functions as a sealing material to maintain the airtightness of the energy storage device 10. In addition, the gasket 23 also has the function of electrically insulating the battery case 12 and the terminal board 21. In this regard, the gasket 23 can be made of a relatively flexible insulating material such as synthetic resin.

[0045] As shown in Figure 2, an annular recess 12F is formed around the entire circumference of the battery case 12, recessed inward, between the opening 12A in the height direction of the battery case 12 and the housing position of the upper insulating plate 17. This annular recess 12F supports the electrode body 11 and the like housed inside the battery case 12. In addition, the upper surface of this annular recess 12F functions as a mounting surface on which the outer periphery of the terminal plate 21 of the lid 13 is placed via the gasket 23.

[0046] As described above, the opening 12A of the battery case 12 is bent with a gasket 23 interposed between it and the lower surface of the outer circumference of the terminal plate 21 of the lid 13, which is placed on the upper surface of the annular recess 12F, the side surface of the lid 13 including the terminal plate 21, and the upper surface of the lid 13. Then, by applying pressure from above and below using a pressurizing device (not shown), the gasket 23 and the lid 13 are crimped and fixed to the inside of the opening 12A, as shown in Figures 2 and 3. The crimped portion F ensures airtightness in that portion by interposing the gasket 23 between the battery case 12 and the lid 13, while also achieving insulation between the battery case 12 and the lid 13.

[0047] In the energy storage device 10, which includes the configuration described above, slight leakage may occur due to, for example, an increase in pressure inside the battery case 12 or an external impact. In addition, most of the aforementioned leakage occurs around the crimped portion F. Therefore, the energy storage device 10 is provided with a sealing member 30 to seal the crimped portion F. The sealing member 30 is made of a resin material such as synthetic resin, and a cured resin is used as an example. As shown in Figures 2 and 3, the sealing member 30 is positioned to cover the tip portion 12B of the battery case 12, the gasket 23, and the upper surface of the lid 13. In this embodiment, the upper surface of the sealing member 30 is positioned on the other end side (downward side) of the outer wall portion 12C (upward side) (position of arrow R2).

[0048] In the energy storage device 10 equipped with the safety valve 22 described above, depending on how the sealing member is filled, for example, if the sealing member is provided close to the safety valve 22, there is a risk that the opening of the safety valve 22 may be obstructed. Therefore, in the energy storage device 10 of this embodiment, as shown in Figures 2 and 3, the cover 13 is provided with an annular recess 13D on the peripheral edge of the cover 13, spaced apart from the safety valve 22 when viewed from above, with one end (upper side) in the vertical direction being open. In this embodiment, as an example, the recess 13D is provided on the outer peripheral portion 13C of the cover 13. As shown in Figure 3, the recess 13D comprises an inner wall 13E on the radially inner side, an outer wall 13F on the radially outer side, and a bottom wall 13G, with the inner wall 13E corresponding to a partition wall.

[0049] As shown in Figures 3 and 4, the sealing member 30, indicated by the colored area, seals the radially outer side of the outer periphery 13C of the lid 13, including the upper surface of a portion of the bottom wall 13G on the outer wall 13F side of the recess 13D, the gasket 23, and the tip portion 12B. The sealing member 30 is positioned to seal at least the contact portion between the tip portion 12B of the lid 13 and the outer periphery 13C of the lid 13 via the gasket 23.

[0050] Next, the effects and benefits of the energy storage device 10 in the first embodiment will be described.

[0051] In the first embodiment of the energy storage device 10, a recess 13D is provided at a position radially outward from the safety valve 22, i.e., at a peripheral edge spaced apart from the safety valve 22 when viewed from the vertical direction, and radially inward from the crimped portion F, and has an annular inner wall 13E that extends toward one end. Furthermore, the energy storage device 10 is provided with a sealing member 30 located radially outward from the inner wall 13E, positioned on the other end side of the battery case 12 beyond the end on the one end side, to seal the crimped portion F. Therefore, in the energy storage device 10, the crimped portion F1, which requires a higher level of sealing, can be sealed by the sealing member 30. Moreover, the inner wall 13E provided radially between the sealing member 30 and the safety valve 22 suppresses the movement of the sealing member 30 toward the safety valve 22, thereby preventing the sealing member 30 from blocking the multiple vents provided on the outer peripheral surface of the central portion 13B of the lid 13, and preventing the opening of the safety valve 22 from being obstructed.

[0052] Furthermore, in the energy storage device 10 according to the first embodiment, it is also possible to prevent the sealing member 30 from adhering to the positive electrode busbar (not shown), thereby suppressing interference with busbar welding to the positive electrode busbar.

[0053] Furthermore, in the energy storage device 10 according to the first embodiment, the crimped portion F, when viewed from a direction perpendicular to the vertical direction (axial direction) (X direction), has an upper end of the outer wall portion 12C, which is one end on the radially outer side, spaced further from the cover 13 than the upper surface of the tip portion 12B, which is one end on the radially inner side. In other words, the upper end of the outer wall portion 12C, which is one end on the radially outer side, is located on the one-end side (above side) than the upper surface of the upper surface of the tip portion 12B, which is one end on the radially inner side. Therefore, it is possible to suppress the decrease in the sealing performance of the crimped portion F due to the movement of the sealing member 30 radially outward.

[0054] Furthermore, in the energy storage device 10 according to the first embodiment, the crimped portion F, when viewed from a direction perpendicular to the vertical direction (axial direction) (X direction), has an upper end which is the radially inner end of the tip portion 12B that is spaced apart from the cover 13 as it approaches the upper end which is the radially outer end. In other words, the upper surface of the tip portion 12B has a slope that is located downward from the radially outer side toward the inner side. Therefore, the sealing member 30 moves more easily from the radially outer side toward the radially inner side on the upper surface of the tip portion 12B, so the decrease in the sealing performance of the crimped portion due to the movement of the sealing member radially outward can be further suppressed.

[0055] Furthermore, in the energy storage device 10 according to the first embodiment, the battery case 12 is provided with an annular outer wall portion 12C that extends from the crimped portion F toward one end, and the sealing member 30 is positioned on the other end side (below) of the outer wall portion 12C. Therefore, the outer wall portion 12C can suppress the movement of the sealing member 30 outward from the crimped portion F.

[0056] In the first embodiment of the energy storage device 10 described above, the bottom wall 13G of the recess 13D of the lid 13 is formed flat, but the present invention is not limited thereto. Figure 5 is an enlarged cross-sectional view corresponding to Figure 3 showing a modified example of the energy storage device 10 of the first embodiment. As shown in Figure 5, in the modified example, the lid 13 has a slope that moves away from the electrode body 11 from the outer wall 13F located at the periphery in the radial direction to the inner wall 13E corresponding to the partition wall. Specifically, the bottom wall 13G of the recess 13D of the lid 13 has a slope that is located on the upper side as it moves from the radial outside to the inside.

[0057] As described above, in this modified example, the lid 13 has a slope in the radial direction from the outer wall 13F toward the inner wall 13E away from the electrode body 11, so the sealing member 30 moves more easily along the slope and accumulates more easily on the crimped portion F side. This makes it possible to further suppress the decrease in sealing performance at the crimped portion F.

[0058] <Second Embodiment> In the first embodiment of the energy storage device 10 described above, an annular recess 13D is provided on the outer periphery 13C of the lid 13. However, the second embodiment of the energy storage device 10A does not have an annular recess 13D on the lid 40, but instead has a partition wall 40D. Figure 6 is an enlarged cross-sectional view of the energy storage device 10A according to the second embodiment of this disclosure, corresponding to Figure 2. Figure 7 is an enlarged cross-sectional view of the area within frame C, indicated by the dashed line, in Figure 6. Figure 8 is a schematic top view of the energy storage device 10A in Figure 6 as seen from the lid 40 side. Note that in Figures 6 to 8, the same reference numerals are used for the components as in the first embodiment of the energy storage device 10 described above, and their explanation is omitted here.

[0059] In the first embodiment of the energy storage device 10 described above, an annular recess 13D is provided on the outer peripheral portion 13C of the lid 13. However, in the energy storage device 10A of this embodiment, as shown in Figures 6 and 7, the lid 40 does not have an annular recess 13D. Therefore, the outer peripheral portion 40C of the lid 40 is formed to be thinner than the outer peripheral portion 13C of the first embodiment.

[0060] As shown in Figure 7, the lid 40 is provided with an annular partition wall 40D slightly outside the radial center of the outer circumference 40. In other words, the partition wall 40D is located radially outward from the safety valve 22, that is, on the peripheral edge spaced apart from the safety valve 22 when viewed from above. Furthermore, the partition wall 40D is located radially inward from the crimped portion F and extends toward one end (upper side). The partition wall 40D is formed, for example, by bending the housing of the lid 40 so that it overlaps with the other housing. In this embodiment, for example, the end of the partition wall 40D on one end (upper side) and the end of the outer wall portion 12C on one end (upper side) are formed to be at approximately the same height. Furthermore, the partition wall 40D is formed in a position that substantially overlaps with the radially inner end of the other end (downward side) of the gasket 23 when viewed from above, and is formed at a position spaced apart from the tip portion 12B of the battery case 12 and the radially inner end of the one end (upward side) of the gasket 23.

[0061] In this embodiment, the sealing member 30 is positioned between the radially inner surface of the outer wall portion 12C and the radially outer surface of the partition wall 40D, as shown in Figure 7. The sealing member 30 is positioned on the other end side (downward side) of both the partition wall 40D and the outer wall portion 12C, rather than on the one end side (upward side).

[0062] As shown in Figure 8, the sealing member 30, indicated by the colored area, seals the upper surface of the lid 40, which is radially outside the outer peripheral portion 40C of the lid 40 and radially outside the partition wall 40D, the gasket 23, and the tip portion 12B, which is radially inside the outer wall portion 12C. The sealing member 30 is positioned to seal at least the contact portion between the tip portion 12B of the lid 40 and the outer peripheral portion 13C of the lid 40 via the gasket 23.

[0063] Next, the effects and benefits of the energy storage device 10A in the second embodiment will be described.

[0064] In the energy storage device 10A according to the second embodiment, an annular partition wall 40D is provided at a position radially outward from the safety valve 22 and radially inward from the crimped portion F, extending toward one end (upward), and a sealing member 30 is provided radially outward from the partition wall 40D, positioned toward the other end of the partition wall 40D and the battery case 12 toward the other end, to seal the crimped portion F. Therefore, in the energy storage device 10, the crimped portion F1, which requires a higher level of sealing, can be sealed by the sealing member 30. Furthermore, since the partition wall 40D provided radially between the sealing member 30 and the safety valve 22 suppresses the movement of the sealing member 30 toward the safety valve 22, it is possible to prevent the sealing member 30 from blocking the multiple vents provided on the outer circumferential surface of the central portion 13B of the cover 40, and thus prevent the opening of the safety valve 22 from being obstructed.

[0065] Furthermore, in addition to the above, the energy storage device 10A according to the second embodiment can obtain the same effects as the energy storage device 10 of the first embodiment described above.

[0066] <Third Embodiment> The energy storage device 10B of the third embodiment is further equipped with an upper wall portion 12G compared to the configuration of the energy storage device 10A of the second embodiment described above. Figure 9 is an enlarged cross-sectional view of the energy storage device 10B according to the third embodiment of this disclosure corresponding to Figure 2, Figure 10 is an enlarged cross-sectional view of the area within frame C shown by the dashed line in Figure 9 of the energy storage device 10B, and Figure 11 is a schematic top view of the energy storage device 10B of Figure 9 as seen from the lid 40 side. In Figures 9 to 11, the same reference numerals are used for the components as in the energy storage device 10 of the first embodiment and the energy storage device 10A of the second embodiment described above, and their explanation is omitted here.

[0067] As shown in Figures 9 and 10, the energy storage device 10B is provided with an upper wall portion 12G as a third partition wall extending radially inward at one end (upper side) of the outer wall portion 12C. In this embodiment, as an example, the upper wall portion 12G is formed to be substantially parallel to the lid 40. The upper wall portion 12G is formed, as an example, by bending the tip portion 12B on one axial end of the battery case 12 at the position indicated by arrow R1, and also bending it at the position indicated by arrow R5 on the other end (rear end) side of the position indicated by arrow R1. Then, it is formed by bending the battery cases 12 so that they overlap at the positions indicated by arrows R6 and R2 on the other end (rear end) side of the position indicated by arrow R5.

[0068] Furthermore, the battery case 12 is bent at the position indicated by arrow R3, which is further to the other end than the position indicated by arrow R2, and at the position indicated by arrow R4, which is further to the other end than arrow R3, so that it is bent into a shape that surrounds the outer periphery of the lid 40 including the terminal plate 21. In this embodiment, the end on one end side (upper side) of the upper wall portion 12G is at approximately the same height as the end on one end side (upper side) of the partition wall 40D.

[0069] In this embodiment, the energy storage device 10B has the sealing member 30 positioned on the other end side (downward side) of the upper wall portion 12G formed as described above. Specifically, the sealing member 30 is positioned between the lower surface of the other end side (downward side) of the upper wall portion 12G, the radially inner surface of the outer wall portion 12C, and the radially outer surface of the partition wall 40D. The sealing member 30 is positioned on the other end side (downward side) of the end of the partition wall 40D (upper side) and the other end side (downward side) of the upper wall portion 12G.

[0070] As shown in Figures 10 and 11, the sealing member 30, indicated by the colored area, seals the upper surface of the lid 40, which is radially outside the outer peripheral portion 40C of the lid 40 and radially outside the partition wall 40D, the gasket 23, and the tip portion 12B, which is radially inside the outer wall portion 12C and below the upper wall portion 12G. In other words, when viewed from above, the sealing member 30 located on the other end (below) the upper wall portion 12G is not visible. The sealing member 30 is positioned to seal at least the contact portion between the tip portion 12B of the lid 40 and the outer peripheral portion 40C of the lid 40 via the gasket 23.

[0071] Next, the effects and benefits of the energy storage device 10B in the third embodiment will be described.

[0072] In the energy storage device 10B according to the third embodiment, the outer wall portion 12C is provided with an upper wall portion 12G as a third partition wall that extends radially inward at one end (upper side), so that the movement of the sealing member 30 toward one end (upper side) can be suppressed by the upper wall portion 12G.

[0073] Furthermore, in addition to the above, the energy storage device 10B according to the third embodiment can obtain the same effects as the energy storage device 10A of the second embodiment described above.

[0074] <Fourth Embodiment> The fourth embodiment of the energy storage device 10C has a lid 40 that is further equipped with a lid upper wall portion 40E compared to the configuration of the third embodiment of the energy storage device 10B described above. Figure 12 is an enlarged cross-sectional view of the energy storage device 10C according to the fourth embodiment of this disclosure corresponding to Figure 2, Figure 13 is an enlarged cross-sectional view of the area within frame C shown by the dashed line in Figure 12 of the energy storage device 10C, and Figure 14 is a schematic top view of the energy storage device 10C in Figure 12 as seen from the lid 40 side. In Figures 12 to 14, the components are indicated by the same reference numerals as in the first to third embodiments of the energy storage devices 10, 10A, and 10B described above, and their explanation is omitted here.

[0075] As shown in Figures 12 and 13, the energy storage device 10C is provided with a fourth partition wall portion 40E extending radially outward at one end (upper side) of the partition wall 40D of the lid 40. In this embodiment, as an example, the upper wall portion 40E is formed to be substantially parallel to the lid 40. The upper wall portion 40E is formed, as an example, by bending one end (upper side) of the partition wall 40D at the position indicated by arrow R7. In this embodiment, one end (upper side) of the upper wall portion 40E is formed at a lower height than one end (upper side) of the upper wall portion 12G. In other words, the upper wall portion 40E and the upper wall portion 12G are offset in the vertical direction. Furthermore, when viewed from the vertical direction, a portion of the upper wall portion 40E and the upper wall portion 12G overlap.

[0076] In this embodiment, the energy storage device 10C has the sealing member 30 positioned on the other end side (downward side) of the upper lid wall portion 40E formed as described above. Specifically, the sealing member 30 is positioned between the lower surface of the other end side (downward side) of the upper wall portion 12G, the lower surface of the other end side (downward side) of the upper lid wall portion 40E, the radially inner surface of the outer wall portion 12C, and the radially outer surface of the partition wall 40D. The sealing member 30 is positioned on the other end side (downward side) of both the upper lid wall portion 40E and the lower surface of the other end side (downward side) of the upper wall portion 12G.

[0077] As shown in Figures 13 and 14, the sealing member 30 seals the upper surface of the lid 40, which is radially outside the outer peripheral portion 40C of the lid 40 and radially outside the partition wall 40D, the gasket 23, and the tip portion 12B, which is radially inside the outer wall portion 12C and below the upper wall portion 40E and upper wall portion 12G of the lid. In other words, in the energy storage device 10C of this embodiment, when viewed from above, the upper wall portion 40E and upper wall portion 12G of the lid are arranged to overlap, so the sealing member 30 located on the other end side (below) of the upper wall portion 40E and upper wall portion 12G of the lid is not visible. The sealing member 30 is arranged to seal at least the tip portion 12B of the lid 40 and the contact portion between the outer peripheral portion 40C of the lid 40 via the gasket 23.

[0078] Next, the effects and benefits of the energy storage device 10C in the fourth embodiment will be described.

[0079] In the energy storage device 10C according to the fourth embodiment, the lid 40 is provided with a lid upper wall portion 40E as a fourth partition wall that extends radially outward at one end (upper side) of the partition wall 40D, so that the movement of the sealing member 30 toward the safety valve 22 can be further suppressed by the lid upper wall portion 40E.

[0080] Furthermore, in the energy storage device 10C according to the fourth embodiment, the upper wall portion 12G and the lid upper wall portion 40E are offset in the vertical direction, and when viewed from the vertical direction, a portion of the upper wall portion 12G and the lid upper wall portion 40E overlap, so the upper wall portion 12G and the lid upper wall portion 40E can suppress the outflow of the sealing member 30 from one end.

[0081] Furthermore, in addition to the above, the energy storage device 10C according to the fourth embodiment can obtain the same effects as the energy storage device 10B of the third embodiment described above.

[0082] In the energy storage device 10C according to the fourth embodiment described above, the upper wall portion 12G and the lid upper wall portion 40E are offset in the vertical direction, and when viewed from above, a portion of the upper wall portion 12G and the lid upper wall portion 40E overlap, but the present invention is not limited to this. Figure 15 is an enlarged cross-sectional view corresponding to Figure 13 showing a modified example of the energy storage device 10C according to the fourth embodiment. As shown in Figure 15, in the modified example, the upper wall portion 12G and the lid upper wall portion 40E are in substantially the same vertical position, and their radial ends, i.e., the inner end of the upper wall portion 12G and the outer end of the lid upper wall portion 40E, are joined. Known techniques such as welding and adhesives are used for joining.

[0083] In the above modified example, the upper wall portion 12G and the lid upper wall portion 40E are joined at their radial ends when viewed from above and below, so the upper wall portion 12G and the lid upper wall portion 40E can further suppress the outflow of the sealing member 30 from one end.

[0084] Furthermore, in the first to fourth energy storage devices 10 to 10C described above, the battery case 12 is provided with an outer wall portion 12C as a second partition wall, but the present invention is not limited to this, and the outer wall portion 12C may not be provided. Figure 16 is an enlarged cross-sectional view corresponding to Figure 7 of an energy storage device that does not have an outer wall portion 12C. As shown in Figure 16, the crimped portion F can be clamped and crimped at the tip portion 12B and the bottom portion 12E by a pressing device (not shown) from above and below. Therefore, when viewed from a direction perpendicular to the vertical direction (axial direction) (X direction), the upper end of the tip portion 12B, which is one end on the radially outer side, is spaced further from the lid 13 than the upper end of the radially inner tip portion 12B, which is one end on the radially inner side. In other words, the radially outer side of the tip portion 12B is located on the one-end side (upper side) than the radially inner side.

[0085] Thus, when the outer wall portion 12C is not provided, the sealing member 30 is positioned so as to be located on the other end side (downward side) of the radially outer end (upper end) of the tip portion 12B. Specifically, the sealing member 30 seals the radially outer side of the outer peripheral portion 40C of the lid 40, the gasket 23, and the tip portion 12B. The sealing member 30 is positioned to seal at least the contact portion between the tip portion 12B of the battery case 12 and the outer peripheral portion 40C of the lid 40 via the gasket 23.

[0086] As described above, even if the outer wall portion 12C is not provided, the radially outer upper end of the tip portion 12B is located above the radially inner upper end, so it is possible to suppress the decrease in the sealing performance of the crimped portion F due to the movement of the sealing member 30 radially outward.

[0087] [supplementary explanation] In the energy storage device 10 according to the above embodiment, the lid 13 had a convex shape with a central portion 13B and an outer peripheral portion 13C, as shown in Figure 2, for example, but the present invention is not limited thereto. The lid 13 of the energy storage device 10 may have a planar shape in which the upper surface of the central portion 13B and the upper surface of the outer peripheral portion 13C are located on the same plane. Even with a planar shape, a recess 13D can be provided, so the same effects as in the above embodiment can be obtained.

[0088] Furthermore, while the energy storage devices 10A to 10C according to the second to fourth embodiments described above had a convex shape in which the lid 40 had a central portion 13B and an outer peripheral portion 40C, as shown in Figure 6, the present invention is not limited thereto. The lid 40 of the energy storage devices 10A to 10C may have a planar shape in which the upper surface of the central portion 13B and the upper surface of the outer peripheral portion 40C are located on the same plane. Since a partition wall 40D can be provided even in a planar shape, the same effects as those of the second to fourth embodiments described above can be obtained.

[0089] Furthermore, in the energy storage devices 10B to 10C according to the third and fourth embodiments described above, the upper wall portion 12G and the lid upper wall portion 40E are arranged substantially parallel to the lid 40 (terminal board 21), but the present invention is not limited thereto. For example, the upper end surfaces of the upper wall portion 12G and the lid upper wall portion 40E may have a slope.

[0090] Furthermore, in the embodiments described above, the outer wall portion 12C, the partition wall 40D, the upper wall portion 12G, and the upper lid wall portion 40E are formed by bending the housing, but the present invention is not limited thereto, and they may be formed by methods other than bending.

[0091] This disclosure is not limited to the embodiments described above, and can be implemented with various modifications without departing from the spirit of this disclosure. All such modifications are included in the technical concept of this disclosure. Furthermore, unless otherwise specified in the specification, each component of this disclosure is not limited to one, but may exist in multiple forms. [Explanation of Symbols]

[0092] 10, 10A~10C power storage device 11 Electrode body 12 Battery case (casing) 12C External wall (second bulkhead) 12G Upper wall (3rd bulkhead) 13, 40 Lid 30 sealing member 40E Lid upper wall (4th bulkhead) 13D recess 13E Inner wall (bulkhead) 22 Safety valve 40D Bulkhead F crimping part

Claims

1. A cylindrical housing containing an electrode body and having a central axis in the first direction, At one end of the housing in the first direction, a lid is fixed by a crimped portion formed by crimping the housing, A safety valve positioned so as to coincide with the central axis when viewed from the first direction, The cover is provided radially outward from the safety valve and radially inward from the crimped portion, and has an annular partition wall extending toward the one end, A sealing member is provided on the radially outer side of the partition wall, positioned on the other end side of the housing beyond the one end side, to seal the crimped portion. A power storage device equipped with the following features.

2. The cover is positioned radially apart from the safety valve when viewed from the first direction and has an annular recess with one end in the first direction open. The energy storage device according to claim 1, wherein the partition wall is composed of the inner wall radially inward of the recess.

3. The energy storage device according to claim 1, wherein, when viewed from a direction perpendicular to the first direction, one radially outer end of the crimped portion is spaced further from the cover than one radially inner end.

4. The energy storage device according to claim 3, wherein the crimped portion is spaced apart from the cover when viewed from a direction perpendicular to the first direction, from one end on the radially outer side toward one end on the radially inner side.

5. The lid has an inclination in the radial direction that moves away from the housing from the periphery toward the partition wall, as described in claim 1.

6. The housing includes an annular second partition wall extending from the crimped portion toward the one end, The energy storage device according to claim 1, wherein the sealing member is positioned on the other end side of the second partition wall than the end on the one end side.

7. The second partition wall is provided with a third partition wall extending radially inward at the end on the one end side, The energy storage device according to claim 6, wherein the sealing member is positioned on the other end side of the third partition wall.

8. The end of the aforementioned partition wall on the one end side is provided with a fourth partition wall that extends radially outward, The energy storage device according to claim 7, wherein the sealing member is positioned on the other end side of the fourth partition wall.

9. The energy storage device according to claim 8, wherein the third partition and the fourth partition are offset in the first direction, and when viewed from the first direction, a portion of the third partition and the fourth partition overlap.

10. The energy storage device according to claim 8, wherein the third partition and the fourth partition are joined at their radial ends when viewed from the first direction.

Images