Electricity storage device

Abstract

The invention relates to a power storage device. A power storage device is provided with a plurality of power storage cells, a bottom wall, a panel member that defines a smoke discharge path together with the bottom wall, and a protection member. And a safety valve is arranged on the lower surface of each power storage monomer. The bottom wall has a plurality of through holes. The protective member includes a plurality of cylindrical portions protruding from each of the through holes toward the panel member.

Description

Technical Field

[0001] This disclosure relates to energy storage devices. Background Technology

[0002] For example, Japanese Patent Application Publication No. 2024-501935 discloses an electrical device comprising a plurality of battery cells, a first frame housing the plurality of battery cells, a second frame housing the first frame, and an isolation member disposed within the second frame. The isolation member supports the first frame at a position above the bottom surface of the second frame. A collection chamber is formed below the isolation member within the second frame. A third vulnerable region is provided on the lower surface of the battery cell casing, a pressure relief region is provided on the bottom surface of the first frame, and a second vulnerable region is provided on the isolation member. The second vulnerable region is made of a material having a lower melting point than the regions outside the second vulnerable region in the isolation member. Excrement passing through the third vulnerable region of the battery cell and discharged from the battery cell flows into the collection chamber formed below the isolation member via the pressure relief region and the second vulnerable region. Summary of the Invention

[0003] In the electrical apparatus described in Japanese Patent Publication No. 2024-501935, gas contained in the discharge from a battery cell may come into contact with the lower surface of a battery cell adjacent to a storage cell.

[0004] The purpose of this disclosure is to provide an energy storage device that can prevent discharge from a single energy storage cell from contacting the safety valve of an adjacent energy storage cell.

[0005] An energy storage device according to one aspect of this disclosure includes: a plurality of energy storage cells arranged in one direction; a bottom wall disposed below the plurality of energy storage cells; a panel member disposed below the bottom wall and defining a smoke exhaust path together with the bottom wall; and a protective member disposed on the bottom wall, wherein a safety valve is disposed on the lower surface of each of the plurality of energy storage cells, the bottom wall having a plurality of through holes respectively disposed opposite to each of the safety valves, and the protective member including a plurality of cylindrical portions protruding from the plurality of through holes toward the panel member.

[0006] The above and other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description of the invention, which is understood in conjunction with the accompanying drawings. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of a vehicle equipped with an energy storage device according to one embodiment of the present disclosure.

[0008] Figure 2 It is a three-dimensional diagram that roughly represents an energy storage device.

[0009] Figure 3 It is a plan view that roughly shows the state of the battery storage device with the top cover removed.

[0010] Figure 4 It is along Figure 3 A cross-sectional view along line IV-IV.

[0011] Figure 5 It is along Figure 3 A cross-sectional view of the VV line.

[0012] Figure 6 It is a three-dimensional drawing that roughly represents the protective components.

[0013] Figure 7 It is a rough cross-sectional view of the protective component.

[0014] Figure 8 It is a cross-sectional view that roughly represents a modified example of the protective component.

[0015] Figure 9 It is a cross-sectional view that roughly represents a modified example of the protective component.

[0016] Figure 10 It is a perspective view that roughly represents a modified example of a protective component.

[0017] Figure 11 It is a perspective view that roughly represents a modified example of a protective component.

[0018] Figure 12 yes Figure 11 The cross-sectional view of the protective component shown.

[0019] Figure 13 It is a perspective view that roughly represents a modified example of a protective component.

[0020] Figure 14 yes Figure 13 The cross-sectional view of the protective component shown.

[0021] Figure 15 It is a cross-sectional view that roughly shows the relationship between the protective components and the column elements.

[0022] Figure 16 It is a plan view that roughly represents the column element.

[0023] Figure 17 It is a cross-sectional view that roughly shows the relationship between the protective components and the column elements.

[0024] Figure 18 It is a plan view that roughly represents the column element. Detailed Implementation

[0025] Embodiments of this disclosure will be described with reference to the accompanying drawings. Furthermore, in the drawings referred to below, the same or equivalent components are given the same reference numerals.

[0026] Figure 1 This is a schematic diagram of a vehicle equipped with an energy storage device according to one embodiment of the present disclosure. Figure 2 It is a three-dimensional diagram that roughly represents an energy storage device. Figure 3 It is along Figure 2 A sectional view along line III-III. Figure 4 It is along Figure 3 A cross-sectional view along line IV-IV. Figure 5 It is along Figure 3 A cross-sectional view of the VV line.

[0027] like Figure 1 As shown, vehicle 1 includes a vehicle body 2 and an energy storage device 10. Examples of vehicles 1 include hybrid electric vehicles, plug-in hybrid electric vehicles, and battery electric vehicles.

[0028] like Figure 1 As shown, the vehicle body 2 includes a frame member 20. The frame member 20 is disposed at the bottom of the vehicle body 2. The frame member 20 is formed in a generally square cylindrical shape that surrounds the energy storage device 10.

[0029] The energy storage device 10 is installed on the frame member 20. For example... Figures 1-5 As shown, the energy storage device 10 includes six energy storage stacks 11-16, a frame 200, equipment 300, an equipment cooler 350, refrigerant piping 400, and protective components 500. Furthermore, the number of energy storage stacks is not limited to six.

[0030] Each of the energy storage stacks 11-16 is formed as a rectangular parallelepiped that is longer in the first direction. For example... Figure 2 As shown, the six battery stacks 11-16 are arranged in a second direction orthogonal to both the first direction and the vertical direction. Each battery stack 11-16 includes multiple battery cells 100 and multiple cooling plates 150.

[0031] Multiple energy storage cells 100 are arranged along a first direction. For example... Figure 4 As shown, each battery cell 100 has an electrode body 112, a cell housing 114 and a pair of external terminals 116.

[0032] The electrode body 112 can be composed of a wound body formed by winding positive and negative electrode sheets with a separator in between, or it can be composed of a laminated body formed by stacking positive and negative electrode sheets with a separator in between. The electrode body 112 is formed into a shape that is elongated in the second direction.

[0033] The single-unit housing 114 houses the electrode body 112. The single-unit housing 114 is formed in a cuboid shape. The single-unit housing 114 is made of a metal such as aluminum. A safety valve SV is provided on the lower surface of the single-unit housing 114.

[0034] A pair of external terminals 116 are disposed on the upper surface of the single housing 114. The pair of external terminals 116 are disposed at positions that are separated from each other in the width direction of the single housing 114. In addition, the width direction corresponds to a second direction.

[0035] like Figure 4 and Figure 5 As shown, each cooling plate 150 is disposed between a pair of adjacent energy storage cells 100 in the first direction. Each cooling plate 150 is formed as a flat plate that is elongated in the second direction. Each cooling plate 150 has a flow path (not shown) for refrigerant to flow in the second direction.

[0036] The 200mm frame can accommodate six battery packs, sized 11-16mm. Figure 4 and Figure 5 As shown, the frame 200 has a lower shell 210, an upper cover 220, and a panel component 230.

[0037] The lower housing 210 has an opening at the top. The lower housing 210 may be formed of a metal such as aluminum. The lower housing 210 has a bottom wall 212, a peripheral wall 214, and a pair of partition walls 216.

[0038] The bottom wall 212 is located below each of the battery stacks 11-16. In this embodiment, the bottom wall 212 is hollow. The bottom wall 212 can be formed by extrusion molding. However, the bottom wall 212 can also be formed as a solid and flat plate. Figure 4 and Figure 5 As shown, multiple through holes 212h are formed in the bottom wall 212. Each through hole 212h is located opposite to the safety valve SV.

[0039] The peripheral wall 214 rises from the periphery of the bottom wall 212. The peripheral wall 214 has a shape that surrounds each of the battery packs 11 to 16. The peripheral wall 214 may be hollow. The peripheral wall 214 has a front wall 214a and a pair of side walls 214b.

[0040] The front wall 214a is formed on one side of each of the battery packs 11-16 in the first direction. Figure 3 (Left side of the vehicle). The front wall 214a extends in the second direction. In addition, in this embodiment, one side in the first direction corresponds to the front side in the longitudinal direction of the vehicle.

[0041] A pair of sidewalls 214b are spaced apart from each other in a second direction. Each sidewall 214b extends in a first direction. The end (front end) of each sidewall 214b on one side in the first direction is connected to the front wall 214a.

[0042] A pair of partition walls 216 divides the space surrounded by the bottom wall 212 and the peripheral wall 214 into spaces for arranging the individual battery stacks 11-16 and other spaces. The pair of partition walls 216 are arranged separately from each other in a first direction. Each partition wall 216 extends in a second direction. Each partition wall 216 may be hollow. The pair of partition walls 216 have the function of restricting the individual battery stacks 11-16 from both sides in the first direction. Figure 3 As shown, the end of the partition wall 216 formed on one side (front side) in the first direction is separated from each side wall 214b in the second direction. The end of the partition wall 216 formed on the other side (rear side) in the first direction is connected to each side wall 214b in the second direction.

[0043] The upper cover 220 is positioned above each of the battery stacks 11 to 16. The upper cover 220 and the lower housing 210 together house the six battery stacks 11 to 16. Specifically, the upper cover 220 and the lower housing 210 together house the six battery stacks 11 to 16 in a sealed state. The periphery of the upper cover 220 is connected to the upper end of the peripheral wall 214 via bolts or other sealing members.

[0044] The panel member 230 is disposed below the lower housing 210. The panel member 230 functions to protect the bottom wall 212 of the lower housing 210. The panel member 230 may be formed in the shape of a flat plate. The periphery of the panel member 230 is connected to the lower surface of the lower housing 210 via a sealing member.

[0045] like Figure 4 and Figure 5 As shown, a space S is formed between the panel member 230 and the bottom wall 212. Each space S functions as a smoke exhaust path (hereinafter referred to as "smoke exhaust path S"). The smoke exhaust path S is a path for discharging the gas discharged from the safety valve SV of the battery cell 100 to the outside of the frame 200.

[0046] like Figure 3 and Figure 5 As shown, a smoke exhaust duct section 218 is formed on the peripheral wall 214. The smoke exhaust duct section 218 extends upward from the bottom wall 212. The smoke exhaust duct section 218 guides gas upward from the smoke exhaust path S. An explosion-proof valve 290 is provided at the downstream end of the smoke exhaust duct section 218. The explosion-proof valve 290 releases the pressure inside the frame 200. When the pressure inside the frame 200 is above a reference value, the explosion-proof valve 290 opens. The explosion-proof valve 290 is composed of a check valve. Figure 5As shown, when gas is discharged from any of the battery cells 100, the gas diffuses in the first direction through the exhaust path S and is discharged to the outside of the frame 200 through the exhaust pipe section 218 and the explosion-proof valve 290.

[0047] Equipment item 300 is stored within frame 200. For example... Figure 3 As shown, device type 300 is disposed on the other side of the lower housing 210 in the first direction, that is, in the space formed between the peripheral wall 214 and the partition wall 216 formed on the other side (rear side) in the first direction. Device type 300 may include a junction box. Device type 300 may include relays, control devices, etc.

[0048] Equipment cooler 350 cools equipment 300. For example... Figure 3 and Figure 5 As shown, the equipment cooler 350 is disposed between the bottom wall 212 and the equipment 300. A thermally conductive adhesive 900 may be disposed between the equipment cooler 350 and the bottom wall 212.

[0049] Refrigerant piping 400 is arranged within the frame 200. Refrigerant piping 400 is connected to each cooling plate 150 and the equipment cooler 350. For example... Figure 2 and Figure 3 As shown, an inflow port 181 and an outflow port 182 are provided on the front wall 214a of the peripheral wall 214. A refrigerant piping 400 is connected to the inflow port 181 and the outflow port 182. Therefore, refrigerant (water, oil, etc.) supplied from the inflow port 181 flows through the refrigerant piping 400 into each cooling plate 150 and the equipment cooler 350, and after cooling each battery cell 100 and the equipment 300, flows out through the refrigerant piping 400 from the outflow port 182.

[0050] like Figure 3 As shown, the refrigerant piping 400 has an upstream piping 410 and a downstream piping 420.

[0051] The upstream end of the upstream piping 410 is connected to the inflow port 181. The downstream end of the upstream piping 410 is connected to one end of the equipment cooler 350 in the second direction. The upstream piping 410 is arranged between the front wall 214a and the partition wall 216 formed on one side in the first direction, and between the battery stack 11 disposed on one side in the second direction and the side wall 214b. The upstream piping 410 is connected to one end of each cooling plate 150 in the second direction.

[0052] The upstream end of the downstream piping 420 is connected to the other end of the equipment cooler 350 in the second direction. The downstream end of the downstream piping 420 is connected to the outlet port 182. The downstream piping 420 is arranged between the front wall 214a and the partition wall 216 formed on one side in the first direction, and between the battery stack 16 disposed on the other side in the second direction and the side wall 214b. The downstream piping 420 is connected to the other end of each cooling plate 150 in the second direction.

[0053] A protective member 500 is disposed on the bottom wall 212. The protective member 500 functions to protect each individual battery cell 100 from the effects of gas discharged from the safety valve SV. The protective member 500 is, for example, made of synthetic resin. Figures 4-7 As shown, the protective member 500 has multiple cylindrical portions 510, multiple flanges 520, and multiple closure portions 530.

[0054] Each cylindrical portion 510 protrudes from each through hole 212h toward the panel member 230. The lower end portion 512 of the cylindrical portion 510 separates upward from the panel member 230. In this embodiment, as... Figure 6 As shown, the cylindrical portion 510 is formed in a cylindrical shape. However, the cross-sectional shape of the cylindrical portion 510 is not particularly limited. For example, the cylindrical portion 510 can be formed in a square cylindrical shape.

[0055] A flange 520 extends outward from the upper end of the cylindrical portion 510. The flange 520 may be formed in an annular shape. The outer shape of the flange 520 is larger than the outer shape of the through hole 212h. The flange 520 is in contact with the upper surface of the bottom wall 212. The flange 520 has the function of preventing the cylindrical portion 510 from falling from the bottom wall 212 onto the panel member 230.

[0056] The sealing section 530 seals the interior of the cylindrical section 510. For example... Figure 7 As shown, the thickness of the sealing portion 530 is less than the thickness of the cylindrical portion 510. The sealing portion 530 is configured to be strong enough to crack due to the discharge containing gas discharged from the safety valve SV.

[0057] In the energy storage device 10 described above, when discharge material is discharged downwards from the safety valve SV due to a short circuit or other cause in any of the individual energy storage cells 100, the discharge material collides with the sealing portion 530. This causes the sealing portion 530 to crack, allowing the discharge material to flow into the exhaust path S. Then, the gas contained in the discharge material diffuses in the exhaust path S, such as... Figure 5 As shown, it is discharged from the frame 200 through the explosion-proof valve 290.

[0058] Here, when the gas flowing into the exhaust path S through the cylinder 510 diffuses within the exhaust path S, such as Figure 4 and Figure 5As shown, the gas forms a swirling flow within the cylinder 510 located below the adjacent battery cell 100 (hereinafter referred to as "adjacent battery cell") that has discharged the exhaust. Therefore, the possibility of the gas coming into contact with the safety valve SV of the adjacent battery cell due to rising within the cylinder 510 is suppressed.

[0059] Furthermore, since the protective member 500 in this embodiment includes a sealing portion 530, the gas rising in the cylinder portion 510 located below the adjacent battery cell is effectively cut off by the sealing portion 530.

[0060] The following describes variations of the above-described embodiments.

[0061] <First Variation>

[0062] like Figure 8 As shown, the closure portion 530 of the protective member 500 may have a central portion 532 and an edge portion 534.

[0063] The central portion 532 is formed as a thick wall. The thickness of the central portion 532 can be greater than the thickness of the cylindrical portion 510.

[0064] An edge portion 534 is formed around the central portion 532. The edge portion 534 is connected to the central portion 532 and the cylindrical portion 510. The thickness of the edge portion 534 is less than the thickness of the central portion 532. The thickness of the edge portion 534 is less than the thickness of the cylindrical portion 510.

[0065] In this method, when the discharge is discharged from a battery cell 100, the central part 532 falls due to the cracking of the edge 534, and the discharge flows into the smoke exhaust path S.

[0066] <Second Variation>

[0067] like Figure 9 As shown, the cross-sectional area of ​​the cylindrical portion 510 in a plane orthogonal to the vertical direction can gradually decrease as it approaches the panel member 230. For example, the cylindrical portion 510 has a shape in which the diameter gradually decreases as it approaches the panel member 230.

[0068] <Third Variation>

[0069] like Figure 10 As shown, the protective member 500 may include a connecting portion 540 that connects a pair of cylindrical portions 510 adjacent to each other or a pair of flanges 520 to each other in at least one of a first direction and a second direction. Figure 10 In the example shown, the connecting portion 540 connects a pair of adjacent flanges 520 to each other.

[0070] <Fourth Variation>

[0071] like Figure 11 and Figure 12 As shown, the protective member 500 may include a protrusion 550 that protrudes radially outward from the outer side of the cylindrical portion 510.

[0072] In this example, the cylindrical portion 510 has an arm portion 515. The arm portion 515 is formed between a pair of slits 510S disposed in the cylindrical portion 510. Each slit 510S extends upward from the lower end portion 512 of the cylindrical portion 510. The arm portion 515 is elastically deformable, such that the lower end portion of the arm portion 515 is displaced radially upward relative to the upper end portion of the arm portion 515 in the cylindrical portion 510.

[0073] A protrusion 550 is provided on the outer side of the lower end of the arm portion 515. The protrusion 550 is located below the bottom wall 212 and is opposite to the lower surface of the bottom wall. The length between the lower surface of the flange 520 and the upper surface of the protrusion 550 is set to be the same as or slightly greater than the thickness of the bottom wall 212.

[0074] In this example, by inserting the cylindrical portion 510 into the through hole 212h from above the bottom wall 212, the arm portion 515 deforms, causing the protrusion 550 to move radially inward. Furthermore, when the protrusion 550 reaches below the bottom wall 212, the arm portion 515 returns to a neutral position, thereby clamping the bottom wall 212 by the flange 520 and the protrusion 550.

[0075] <Fifth Variation>

[0076] like Figure 13 and Figure 14 As shown, the protective member 500 may include a protrusion 550 and a plurality of legs 560.

[0077] In this example, the protrusion 550 has a shape that extends outward from the outer peripheral surface of the cylindrical portion 510. The protrusion 550 may be formed in an annular shape. The protrusion 550 is provided on the outer peripheral surface of the middle portion in the vertical direction of the cylindrical portion 510. The protrusion 550 is opposite to the lower surface of the bottom wall 212.

[0078] Multiple legs 560 extend downward from the lower end 512 of the cylindrical portion 510. Each leg 560 is positioned to be separated from each other in the circumferential direction of the cylindrical portion 510. The length between the lower end of each leg 560 and the upper surface of the protrusion 550 is set to be equal to or slightly less than the length between the lower surface of the bottom wall 212 and the upper surface of the panel member 230.

[0079] <Sixth Variation>

[0080] like Figure 15 and Figure 16As shown, the energy storage device 10 may include a column element 570. The column element 570 is disposed between the bottom wall 212 and the panel member 230. The column element 570 can be fixed to the upper surface of the panel member 230. Figure 15 As shown, the distance h2 between the upper end of the column element 570 and the lower surface of the bottom wall 212 is shorter than the distance h1 between the upper surface of the panel member 230 and the lower end 512 of the cylinder 510. Figure 16 As shown, the column element 570 can be formed into a hexagonal prism shape in the plan view.

[0081] In this method, such as Figure 15 As indicated by the middle arrow, the gas contained in the exhaust from a battery cell 100 passes between the column element 570 and the bottom wall 212 and toward the explosion-proof valve 290.

[0082] <Seventh Variation>

[0083] like Figure 17 and Figure 18 As shown, the energy storage device 10 may include a column element 570. Additionally, Figure 17 It shows the equivalent of along Figure 18 A cross-section showing the location of the XVII-XVII line.

[0084] In this example, the cylindrical portion 510 is formed in the shape of a hexagonal prism. The lower end of the cylindrical portion 510 is connected to the panel member 230. A cutout 513 for allowing gas to flow out of the cylindrical portion 510 is provided at the lower part of the cylindrical portion 510.

[0085] The column element 570 is disposed between the bottom wall 212 and the panel member 230. The column element 570 can be fixed to the upper surface of the panel member 230. The height of the column element 570 is less than the distance between the lower surface of the bottom wall 212 and the upper surface of the panel member 230.

[0086] Those skilled in the art should understand that the above exemplary embodiments are specific examples of the following methods.

[0087] [Method 1]

[0088] An energy storage device, comprising:

[0089] Multiple battery cells are arranged in one direction;

[0090] The bottom wall is located below the plurality of battery cells;

[0091] A panel component is disposed below the bottom wall and, together with the bottom wall, defines the smoke exhaust space; and

[0092] Protective components are provided on the bottom wall.

[0093] A safety valve is provided on the lower surface of each of the plurality of battery cells.

[0094] The bottom wall has a plurality of through holes respectively disposed at positions opposite to each of the safety valves.

[0095] The protective member includes a plurality of cylindrical portions, each of which protrudes from each of the plurality of through holes toward the panel member.

[0096] In this energy storage device, when exhaust material from one battery cell flows into the exhaust space through the cylinder, the gas contained in the exhaust material forms a swirling flow within the cylinder located below an adjacent battery cell. Therefore, the possibility of gas rising within the cylinder and reaching the safety valve of the adjacent battery cell is suppressed.

[0097] [Method 2]

[0098] According to the energy storage device of method 1, the protective component further includes a sealing portion that encloses the interior of the cylindrical portion.

[0099] In this method, the sealing section is cracked due to the gas discharged from one of the battery cells, thereby allowing the gas to flow effectively into the exhaust space. On the other hand, the gas rising in the cylinder from the exhaust space toward other battery cells is effectively cut off by the sealing section.

[0100] [Method 3]

[0101] According to the energy storage device of method 1 or 2, the cross-sectional area of ​​each of the cylindrical portions on a plane orthogonal to the vertical direction gradually decreases as it moves toward the panel member.

[0102] In this method, gas flow into the cylinder from below is more reliably suppressed.

[0103] [Method 4]

[0104] According to any one of the embodiments 1 to 3, the energy storage device includes a connecting portion that connects a pair of cylindrical portions adjacent to each other in one direction.

[0105] In this method, the handling of multiple cylinders becomes easier.

[0106] [Method 5]

[0107] The energy storage device according to any one of methods 1 to 4, wherein...

[0108] The protective member includes a protrusion that projects from the outer side of the cylindrical portion.

[0109] The protrusion is located below the bottom wall and opposite the bottom wall.

[0110] In this method, even when the panel member comes into contact with the cylindrical portion of the protective member due to an external force (an upward-pushing load) acting from below, the protective member is prevented from separating from the bottom wall upward because the protrusion abuts against the bottom wall from below. Therefore, the collision of the protective member with the lower surface of the battery cell is suppressed.

[0111] [Method 6]

[0112] The energy storage device according to any one of methods 1 to 5, wherein...

[0113] It also includes column elements disposed between the bottom wall and the panel member.

[0114] The distance between the column element and the bottom wall is shorter than the distance between the panel member and the cylindrical part.

[0115] In this method, because the column element abuts against the bottom wall and the panel member before the panel member contacts the cylinder when an external force (an upward pushing load) acts on the panel member from below, the separation of the protective member from the bottom wall upward is suppressed. Therefore, the collision of the protective member with the lower surface of the battery cell is suppressed.

[0116] Although embodiments of the invention have been described, the embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The scope of the invention is set forth in the claims and is intended to cover all modifications within the meaning and scope equivalent to the claims.

Claims

1. An energy storage device, wherein, have: Multiple battery cells are arranged in one direction; The bottom wall is located below the plurality of battery cells; A panel component is disposed below the bottom wall and, together with the bottom wall, defines the smoke exhaust path; as well as Protective components are provided on the bottom wall. A safety valve is provided on the lower surface of each of the plurality of battery cells. The bottom wall has a plurality of through holes respectively disposed at positions opposite to each of the safety valves. The protective member includes a plurality of cylindrical portions, each of which protrudes from each of the plurality of through holes toward the panel member.

2. The energy storage device according to claim 1, wherein, The protective component also includes a sealing section that encloses the interior of the cylindrical portion.

3. The energy storage device according to claim 1 or 2, wherein, The cross-sectional area of ​​each cylindrical portion on a plane orthogonal to the vertical direction gradually decreases as it moves toward the panel member.

4. The energy storage device according to any one of claims 1 to 3, wherein, The protective member includes a connecting portion that connects a pair of cylindrical portions that are adjacent to each other in one direction.

5. The energy storage device according to any one of claims 1 to 4, wherein, The protective member includes a protrusion that projects from the outer side of the cylindrical portion. The protrusion is located below the bottom wall and opposite the bottom wall.

6. The energy storage device according to any one of claims 1 to 5, wherein, It also includes column elements disposed between the bottom wall and the panel member. The distance between the column element and the bottom wall is shorter than the distance between the panel member and the cylindrical part.

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