Power storage device

Abstract

This power storage device comprising a power storage element includes: a case that houses the power storage element and is provided with a through hole; and a connection part that is arranged in the case and connects two members inside the case. The power storage device is configured to enable ventilation between the inside and the outside of the case via the through hole. At least a portion of the connection part is arranged in the through hole when viewed from the penetration direction of the through hole.

Description

Power storage device

[0001] The present invention relates to an electricity storage device.

[0002] Patent document 1 discloses a battery pack in which the case cover has an opening that is covered by a maintenance lid, and during maintenance, the maintenance lid can be removed to access the electrical connection portion that electrically connects the battery module and the busbar unit through the opening.

[0003] Japanese Patent Application Laid-Open No. 2020-98697

[0004] In the above-mentioned Patent Document 1, an opening is formed in the case cover and a maintenance lid is provided to cover the opening in order to make the electrical connection portion accessible, but it is desirable to simplify this configuration.

[0005] The present invention was made by the inventor of the present application by focusing on the above-mentioned problem, and aims to provide an energy storage device that allows access to the connection part connecting two components inside the case with a simple configuration.

[0006] A storage device according to one aspect of the present invention is a storage device comprising a storage element, a case that houses the storage element and has a through hole, and a connection portion that is arranged within the case and connects two components within the case, wherein the storage device is configured to allow ventilation between the inside and outside of the case through the through hole, and at least a portion of the connection portion is arranged within the through hole when viewed from the direction of penetration of the through hole.

[0007] According to the electricity storage device of the present invention, the connection portion that connects two members inside the case can be accessed with a simple configuration.

[0008] FIG. 1 is a perspective view showing the appearance of a power storage device according to an embodiment. FIG. 2 is a perspective view showing a configuration when an outer case is removed from the power storage device according to an embodiment. FIG. 3 is an exploded perspective view showing each component when the power storage device according to an embodiment (excluding the outer case) is disassembled. FIG. 4 is a cross-sectional view showing the connection configuration and arrangement position of a connection part according to an embodiment. FIG. 5 is a cross-sectional view and a front view showing an enlarged view of the connection configuration and arrangement position of a connection part according to an embodiment. FIG. 6 is a cross-sectional view showing the connection configuration and arrangement position of a connection part provided in a power storage device according to a first modified embodiment. FIG. 7 is a cross-sectional view and a front view showing the connection configuration and arrangement position of a connection part provided in a power storage device according to a second modified embodiment. FIG. 8 is an exploded perspective view showing each component when the internal configuration of the outer case of the power storage device according to the second modified embodiment is disassembled.

[0009] (1) One aspect of the present invention provides an energy storage device including an energy storage element, a case that houses the energy storage element and has a through hole, and a connection portion that is disposed within the case and connects two components within the case, wherein the energy storage device is configured to allow ventilation between the inside and outside of the case through the through hole, and at least a portion of the connection portion is disposed within the through hole when viewed from the direction of penetration of the through hole.

[0010] According to this, the power storage device is configured to allow ventilation between the inside and outside of the case via the through-hole of the case, and at least a portion of the connection part connecting two components inside the case is disposed within the through-hole as viewed from the direction of penetration of the through-hole. This allows access to the connection part from the through-hole, which allows ventilation between the inside and outside of the case. Therefore, according to the power storage device, the connection part connecting the two components inside the case can be accessed with a simple configuration.

[0011] (2) In the energy storage device described above in (1), the connection portion may include a shaft portion extending in a direction through the through hole.

[0012] According to the electricity storage device described in (2) above, the connection portion can be accessed through the through-hole of the case, and the two members inside the case can be connected by the shaft portion.

[0013] (3) In the power storage device described in (1) or (2) above, the case may include a ventilation pipe having the through hole.

[0014] According to the electricity storage device described above in (3), the connection portion can be accessed from the through hole of the ventilation pipe provided in the case by using the through hole.

[0015] (4) In the power storage device according to any one of (1) to (3) above, the case may include a film member that covers the through-hole and has air permeability.

[0016] According to the electricity storage device described above in (4), the through-hole in which the membrane member is disposed can be used to access the connection portion from the through-hole.

[0017] (5) In the energy storage device described in (4) above, the film member may be attached to an outer surface of the case around the through hole.

[0018] According to the energy storage device described in (5) above, the energy storage device can be easily manufactured by accessing the connection portion through the through hole in the case, connecting the two components inside the case, and then attaching the membrane component to the outer surface of the case.

[0019] Hereinafter, with reference to the drawings, a description will be given of an energy storage device according to an embodiment of the present invention (including modifications thereof). The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, component placement and connection configurations, manufacturing processes, and the order of manufacturing processes shown in the following embodiments are examples and are not intended to limit the present invention. In each drawing, dimensions and the like are not strictly illustrated. In each drawing, the same or similar components are designated by the same reference numerals.

[0020] In the following description and drawings, the X-axis direction is defined as the direction in which a pair of external terminals (positive and negative), the direction in which a pair of terminals (positive and negative) in one energy storage element, or the direction in which the short side surfaces of the container of one energy storage element face each other. The Y-axis direction is defined as the direction in which the through-holes in the outer case penetrate, the direction in which the energy storage element and the bus bar are aligned, the direction in which the energy storage element and the substrate are aligned, the direction in which the terminals of the energy storage element protrude, or the direction in which the main body and the lid of the container of the energy storage element are aligned. The Z-axis direction is defined as the direction in which the main body and the lid of the outer case of the energy storage device are aligned, the direction in which the multiple energy storage elements are arranged, the direction in which the long side surfaces of the container of one energy storage element face each other, or the up-down direction. The X-axis direction, the Y-axis direction, and the Z-axis direction intersect each other (orthogonal in this embodiment). Depending on the usage mode, the Z-axis direction may not be the up-down direction; however, for convenience of explanation, the Z-axis direction will be described below as the up-down direction.

[0021] In the following description, the positive X-axis direction refers to the direction of the arrow on the X-axis, and the negative X-axis direction refers to the direction opposite to the positive X-axis direction. When simply referring to the X-axis direction, it refers to both or either of the positive X-axis direction and the negative X-axis direction. When referring to one side and the other side of the X-axis direction, it refers to one and the other of the positive X-axis direction and the negative X-axis direction. The same applies to the Y-axis direction and the Z-axis direction. Expressions indicating relative directions or attitudes, such as parallel and perpendicular, also include cases where the directions or attitudes are not strictly the same. When two directions are parallel, it does not only mean that the two directions are completely parallel, but also means that the directions are substantially parallel, that is, there is a difference of, for example, a few percent. In the following description, when the term "insulation" is used, it means "electrical insulation." An insulating material has a volume resistivity of 1×10 １０ It is preferable that the material be made of a material with a resistance of Ωm or more.

[0022] (Embodiment) [1 General Description of Energy Storage Device 10] First, a general description of the energy storage device 10 according to the present embodiment will be provided. FIG. 1 is a perspective view showing the appearance of the energy storage device 10 according to the present embodiment. FIG. 2 is a perspective view showing the configuration of the energy storage device 10 according to the present embodiment with the outer case 100 removed. In the present embodiment, the bus bars 400 (450, 460) are integrally molded (insert molded) into the outer case 100, but FIG. 2 illustrates a state in which only the outer case 100 has been removed from the energy storage device 10. FIG. 3 is an exploded perspective view showing each component of the energy storage device 10 according to the present embodiment (excluding the outer case 100). FIG. 3 illustrates each component when the configuration shown in FIG. 2 is disassembled.

[0023] The power storage device 10 is a device capable of charging with electricity from an external source and discharging electricity to an external source. In this embodiment, the power storage device 10 has a substantially rectangular parallelepiped shape. The power storage device 10 is a battery module (battery assembly) used for power storage, power supply, or the like. Specifically, the power storage device 10 is used as a battery for driving or starting the engine of a moving object such as an automobile, motorcycle, personal watercraft, ship, snowmobile, agricultural machinery, construction machinery, automatic guided vehicle (AGV), or electric railway vehicle. Examples of the automobile include an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and a fossil fuel (gasoline, diesel, liquefied natural gas, etc.) vehicle. Examples of the electric railway vehicle include a train, a monorail, a linear motor car, and a hybrid train equipped with both a diesel engine and an electric motor. The power storage device 10 can also be used as a stationary battery for home or business use.

[0024] 1 to 3 , the energy storage device 10 includes an outer case 100, a plurality of energy storage elements 200, an inner case 300, bus bars 400 (410 to 460), a substrate 500, and a connection portion 600. In addition to the above components, the energy storage device 10 may also include spacers arranged between the plurality of energy storage elements 200, restraining members (side plates, end plates, etc.) that restrain the plurality of energy storage elements 200, bus bar holders that hold the bus bars 400, etc.

[0025] [1.1 Description of Outer Case 100] The outer case 100 is a substantially rectangular parallelepiped (box-shaped) container (module case) that constitutes the exterior body (housing, outer shell) of the energy storage device 10. The outer case 100 is arranged outside the plurality of energy storage elements 200, the inner case 300, the bus bars 400 (410 to 440), the substrate 500, the connection portion 600, etc., and houses these energy storage elements 200, etc. The outer case 100 fixes these energy storage elements 200, etc., in predetermined positions and protects them from impacts, etc. The outer case 100 includes a case main body 110 that constitutes the main body of the outer case 100, a case lid 120 that constitutes the lid of the outer case 100, and a membrane member 130. The case main body 110 and the case lid 120 are joined (sealed) by adhesive, heat sealing, ultrasonic welding, screw fastening with bolts, or the like. As a result, the outer case 100 is configured so that ventilation between the inside and outside of the outer case 100 is not possible from any location other than the membrane member 130 .

[0026] The case body 110 and case lid 120 of the outer case 100 are formed from insulating materials such as polycarbonate (PC), polypropylene (PP), polyethylene (PE), polystyrene (PS), polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyether ether ketone (PEEK), tetrafluoroethylene perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyethersulfone (PES), polyamide (PA), ABS resin, or composite materials thereof. This prevents the energy storage device 200 and other components from coming into contact with external metal components. The case body 110 and case lid 120 may be formed from the same material or different materials. As long as the insulation properties of the energy storage element 200 and the like are ensured, at least one of the case body 110 and the case lid 120 may be formed of a metal member.

[0027] The case body 110 is a bottomed, rectangular cylindrical housing (enclosure) with an opening formed in the negative Z-axis direction, and houses the energy storage device 200 and other components. The case body 110 has outer case sidewalls 111 and 112, which are a pair of flat, long sidewalls, on both sides in the Y-axis direction, outer case sidewalls 113 and 114, which are a pair of flat, short sidewalls, on both sides in the X-axis direction, and an outer case top wall 115, which is a flat, top wall, in the positive Z-axis direction. The outer case sidewall 111 is located at the end of the case body 110 in the negative Y-axis direction and faces the negative Y-axis direction. The outer case sidewall 112 is located at the end of the case body 110 in the positive Y-axis direction and faces the positive Y-axis direction. The outer case sidewall 113 is located at the end of the case body 110 in the positive X-axis direction and faces the positive Y-axis direction. The outer case sidewall 114 is located at the end of the case body 110 in the negative Y-axis direction and faces the negative Y-axis direction. The outer case top wall 115 is located at the end of the case body 110 in the positive Z-axis direction and faces in the positive Z-axis direction. Depending on the configuration (number, size, shape, etc.) of the contents of the outer case 100, the case body 110 (outer case side walls 111-114, outer case top wall 115) may have any shape. In this case, the outer case side walls 111 and 112 may be short side walls, and the outer case side walls 113 and 114 may be long side walls.

[0028] In case body 110, corners located at the end in the negative Y-axis direction and the end in the negative X-axis direction are recessed to form case recess 116, and corners located at the end in the negative Y-axis direction and the end in the positive X-axis direction are recessed to form case recess 117. External terminal portions 461 and 462 of bus bar 460, which will be described later, are exposed from case recess 116, and external terminal portions 451 and 452 of bus bar 450, which will be described later, are exposed from case recess 117. Specifically, external terminal portions 461 and 462 are integrally molded (insert molded) with case body 110 in case recess 116, so that case body 110 and external terminal portions 461 and 462 are integrated with each other with external terminal portions 461 and 462 exposed from case recess 116. In the case recess 117, the external terminal portions 451 and 452 are integrally molded (insert molded) with the case body 110, thereby integrating the case body 110 with the external terminal portions 451 and 452 with the external terminal portions 451 and 452 exposed from the case recess 117. The case body 110 and the external terminal portions 461 and 462 may be integrated (integrally molded) by a method other than insert molding, or may not be integrated (integrally molded). The same applies to the case body 110 and the external terminal portions 451 and 452.

[0029] The outer case side wall 111 of the case main body 110 has a through hole 111a. The through hole 111a is a circular through hole that penetrates the outer case side wall 111 in the Y-axis direction and is viewed from the Y-axis direction. In this embodiment, the outer case side wall 111 has a vent pipe 111b, and the through hole 111a is an opening formed in the vent pipe 111b. In other words, the outer case side wall 111 has a vent pipe 111b with the through hole 111a. The vent pipe 111b is a tubular (cylindrical) pipe member that protrudes in the Y-axis negative direction from the outer wall surface of the outer case side wall 111 in the Y-axis negative direction and extends in the Y-axis negative direction. The vent pipe 111b is an exhaust pipe that discharges gas from the energy storage elements 200 to the outside of the outer case 100 (outside the energy storage device 10). A pipe member (not shown) such as a gas hose can be connected to the vent pipe 111b. In this embodiment, the vent pipe 111b is provided at the center in the X-axis direction and the center in the Z-axis direction of the outer case side wall 111. The vent pipe 111b is formed integrally with other parts of the case body 110, but may also be configured as a separate part from the other parts. In this way, the outer case 100 is provided with the through hole 111a (the vent pipe 111b having the through hole 111a is provided). The outer case 100 is an example of a case having a through hole.

[0030] The case cover 120 is a flat rectangular member that closes the opening of the case body 110 in the negative Z-axis direction. In this embodiment, the case cover 120 is a flat plate-like member that forms the bottom wall of the outer case 100, and is disposed in the negative Z-axis direction of the case body 110. The case cover 120 may be a rectangular cylindrical member with a bottom that has an opening formed in the positive Z-axis direction. The case body 110 may be a rectangular cylindrical member with a bottom that has an opening formed in the positive Z-axis direction, and the case cover 120 may be a member that closes the opening.

[0031] The membrane member 130 is a breathable membrane member that covers the through-hole 111a of the case body 110. In other words, the membrane member 130 covers (blocks) the through-hole 111a in a breathable manner. That is, the membrane member 130 covers the entire through-hole 111a but does not completely block (block) the flow of gas passing through the through-hole 111a. Specifically, the membrane member 130 has enough breathability to achieve pressure equilibrium between the outside and inside of the outer case 100 under normal conditions. When gas is discharged from the energy storage element 200 and the internal pressure of the outer case 100 becomes excessively high, the membrane member 130 breaks and / or moves (peels off) to open the through-hole 111a. This allows gas inside the outer case 100 to be discharged to the outside of the outer case 100 through the through-hole 111a. In this way, the through-hole 111a is not blocked by a non-ventilable lid, and the energy storage device 10 is configured to allow ventilation between the inside and outside of the outer case 100 via the through-hole 111a. Specifically, the energy storage device 10 is configured to allow ventilation from the inside to the outside of the outer case 100 and from the outside to the inside via the through-hole 111a and the membrane member 130.

[0032] The membrane member 130 is attached to the outer surface of the outer case 100 around the through hole 111a. Specifically, the membrane member 130 is disposed at the tip (the end in the negative Y-axis direction) of the vent pipe 111b and attached to the outer surface (the surface in the negative Y-axis direction) of the tip. In this embodiment, the tip of the vent pipe 111b is recessed, and the membrane member 130 is attached to the recessed portion (see FIGS. 4 and 5 ). However, the tip of the vent pipe 111b may not be recessed, and the membrane member 130 may be attached to the outer surface (the end face in the negative Y-axis direction) of the tip. The membrane member 130 is joined to the vent pipe 111b by welding, such as heat welding, laser welding, or ultrasonic welding, or by adhesion using an adhesive or double-sided tape.

[0033] In this embodiment, the membrane member 130 is a breathable, waterproof membrane made of a breathable and waterproof material. Examples of materials that can be used to form the membrane member 130 include Gore-Tex (registered trademark), TEMISH (registered trademark), C-Porous (registered trademark), Porum (registered trademark), NF Sheet (registered trademark), porous films made from PTFE, porous film composites made from PTFE and PET, porous films made from PE, and porous films made from PP. The membrane member 130 prevents foreign matter such as water from entering the interior of the outer case 100 through the ventilation pipe 111b. The membrane member 130 only needs to be breathable, and may be made of a non-waterproof material such as a non-woven fabric made from PET.

[0034] [1.2 Description of Energy Storage Element 200] The energy storage element 200 is a secondary battery (single cell) capable of charging and discharging electricity, and more specifically, a non-aqueous electrolyte secondary battery such as a lithium-ion secondary battery. The energy storage element 200 has a rectangular parallelepiped shape (rectangular or box-shaped) that is flattened in the Z-axis direction. In this embodiment, four energy storage elements 200 are arranged side by side in the Z-axis direction. The size, shape, and number of the energy storage elements 200 to be arranged are not limited. For example, the energy storage element 200 may have a cylindrical shape, an elongated cylindrical shape, an elliptical cylindrical shape, or a polygonal prism shape other than a rectangular parallelepiped. Only one energy storage element 200 may be arranged. The energy storage element 200 is not limited to a non-aqueous electrolyte secondary battery, and may be a secondary battery other than a non-aqueous electrolyte secondary battery or a capacitor. The energy storage element 200 may be a primary battery instead of a secondary battery. The energy storage element 200 may be a battery using a solid electrolyte, or may be a pouch-type energy storage element.

[0035] The energy storage element 200 includes a container 210 and a pair of terminals 220 (positive and negative electrodes). The container 210 contains an electrode assembly, a pair of current collectors (positive and negative electrodes), an electrolyte (non-aqueous electrolyte), and the like. Gaskets are disposed between the container 210 and the terminals 220 and current collectors, but these are not shown. The type of electrolyte is not particularly limited as long as it does not impair the performance of the energy storage element 200, and various types can be selected. In addition to the above components, the energy storage element 200 may also include spacers disposed on the sides or below the electrode assembly, an insulating film encasing the electrode assembly, or an insulating film (such as a shrink tube) covering the outer surface of the container 210.

[0036] The container 210 is a rectangular parallelepiped (square or box-shaped) container including a container body with an opening and a container lid that closes the opening of the container body. The container body has a pair of long sides on both sides in the Z-axis direction, a pair of short sides on both sides in the X-axis direction, a bottom surface in the positive direction of the Y-axis, and the container lid is disposed in the negative direction of the Y-axis. The container lid is provided with a gas exhaust valve (not shown) that releases pressure inside the container 210 if the pressure inside the container 210 increases excessively, and a liquid injection part (not shown) for injecting electrolyte into the container 210. The material of the container 210 is not particularly limited and can be a weldable metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel plate, but resin can also be used.

[0037] The terminals 220 are electrode terminals (positive and negative terminals) of the energy storage element 200, which are arranged on the container lid of the container 210. The terminals 220 are arranged to protrude from the container 210 in the negative Y-axis direction. The terminals 220 are electrically connected to the positive and negative electrode plates of the electrode body via current collectors. The terminals 220 are made of aluminum, an aluminum alloy, copper, a copper alloy, or the like.

[0038] The electrode assembly is an electricity storage element (power generating element) formed by stacking a positive electrode plate, a negative electrode plate, and a separator. The positive electrode plate is a current collector foil made of a metal such as aluminum or an aluminum alloy, on which a positive electrode active material layer is formed. The negative electrode plate is a current collector foil made of a metal such as copper or a copper alloy, on which a negative electrode active material layer is formed. Any known material capable of absorbing and releasing lithium ions can be used as the active material for the positive electrode active material layer and the negative electrode active material layer. The separator can be a microporous resin sheet or nonwoven fabric. In this embodiment, the electrode assembly is formed by stacking electrode plates (positive electrode plates and negative electrode plates) in the Z-axis direction. The electrode assembly may be of any shape, such as a wound electrode assembly formed by winding electrode plates (positive electrode plates and negative electrode plates), a stacked electrode assembly formed by stacking multiple flat electrode plates, or a bellows-shaped electrode assembly in which electrode plates are folded in a bellows shape.

[0039] The current collectors are conductive current collecting members (positive electrode current collector and negative electrode current collector) electrically connected to the terminal 220 and the electrode assembly. The positive electrode current collector is made of aluminum or an aluminum alloy, etc., like the current collecting foil of the positive electrode plate of the electrode assembly, and the negative electrode current collector is made of copper or a copper alloy, etc., like the current collecting foil of the negative electrode plate of the electrode assembly. The gasket is disposed between the container lid and the terminal 220 and current collector, and provides insulation between the container lid and the terminal 220 and current collector. The gasket may be made of any material as long as it has insulating properties.

[0040] [1.3 Description of the inner case 300] The inner case 300 is a container having a substantially rectangular parallelepiped (box-shaped) shape that constitutes the inner box of the energy storage device 10. The inner case 300 houses a plurality of energy storage elements 200 and fixes the plurality of energy storage elements 200 in predetermined positions. The inner case 300 is formed from any material that can be used for the case body 110 and case lid 120 of the outer case 100.

[0041] Specifically, the inner case 300 has six flat, rectangular walls arranged on both sides of the energy storage elements 200 in the X-axis direction, the Y-axis direction, and the Z-axis direction. Of these six walls, the wall located in the negative Y-axis direction of the energy storage elements 200 is referred to as the inner case wall 310. The inner case wall 310 is provided with openings 311 into which the terminals 220 of the energy storage elements 200 are inserted, connection portions 312 to which the connection portions 600 are connected, and openings (not shown) through which gas discharged from the energy storage elements 200 passes.

[0042] The openings 311 are through holes through which the terminals 220 of the energy storage elements 200 pass, and a plurality of openings 311 (five openings 311 in this embodiment) are provided so that all of the terminals 220 of the plurality of energy storage elements 200 can pass through. The terminals 220 pass through the openings 311 and protrude from the inner case wall 310 in the negative Y-axis direction. As a result, all of the terminals 220 of the plurality of energy storage elements 200 are arranged to protrude from the inner case 300 through the openings 311. The number, size, shape, etc. of the openings 311 are not particularly limited.

[0043] The connection portion 312 is a portion to which a head 611 of a bolt 610 included in the connection portion 600 (described later) is connected. The connection portion 312 is located at the center of the inner case wall portion 310 in the X-axis direction and the Z-axis direction, and is a protrusion that protrudes in the negative Y-axis direction. The connection portion 312 has a recess that is hexagonal when viewed in the Y-axis direction, and the head 611 of the bolt 610, which is hexagonal when viewed in the Y-axis direction, is inserted (fitted) into this recess. This connects (fixes) the bolt 610 to the connection portion 312, restricting rotation of the bolt 610 around its axial direction (the Y-axis direction). In this way, the connection portion 312 has the function of connecting the connection portion 600 (bolt 610) to fix the connection portion 600 (bolt 610) and preventing rotation of the connection portion 600 (bolt 610).

[0044] [1.4 Description of Bus Bar 400] Bus bar 400 is a plate-shaped member electrically connected to energy storage element 200. Bus bar 400 is formed of a conductive member made of metal such as aluminum, aluminum alloy, copper, copper alloy, or nickel, or a combination thereof, or a conductive member other than metal. Bus bar 400 includes three bus bars: bus bar 410, bus bar 420, bus bar 430, bus bar 440, bus bar 450, and bus bar 460.

[0045] The bus bars 410 to 430 are arranged in the negative Y-axis direction of the multiple energy storage elements 200 and the inner case 300, and in the positive Y-axis direction of the substrate 500. The bus bars 410 to 430 are connected (joined) to the multiple energy storage elements 200. The bus bar 420 is connected to the bus bar 460. The bus bar 430 is electrically connected to the bus bars 440 and 450 via the substrate 500. Specifically, the bus bars 410 to 430 electrically connect the terminals 220 of the multiple energy storage elements 200 to each other, electrically connect the terminal 220 of the energy storage element 200 at one end to the bus bars 440 and 450, and electrically connect the terminal 220 of the energy storage element 200 at the other end to the bus bar 460.

[0046] The three bus bars 410 are connected (joined) to the terminals 220 of the four energy storage elements 200, connecting the four energy storage elements 200 in series. The bus bar 420 is connected (joined) to the terminal 220 in the negative X-axis direction of the energy storage element 200 at the end in the positive Z-axis direction. The bus bar 420 is a plate-like member that extends in the negative X-axis direction from the connection portion with the terminal 220, bends in the positive Y-axis direction, extends in the positive Y-axis direction and the negative Z-axis direction, and bends in the negative X-axis direction again.

[0047] Bus bar 420 is connected (fixed) to bus bar 460 by connecting portion 700. In the present embodiment, connecting portion 700 includes bolt 710 and nut 720. Bolt 710 is a bolt (hexagonal bolt) including a shaft portion (shaft body) extending in the Z-axis direction and having a male thread portion formed thereon. Nut 720 is a cylindrical nut including a female thread portion to which the male thread portion of bolt 710 is coupled. Bolt 710 is inserted into through hole 421 formed in bus bar 420 and through hole 463 formed in bus bar 460, and coupled to nut 720. Nut 720 is fixed to case body 110 of outer case 100 by insert molding or the like. In the present embodiment, nut 720 has a circular outer shape when viewed in the Z-axis direction; however, it may have a non-circular outer shape such as a rectangular shape (e.g., hexagonal), an elliptical shape, or an oval shape to prevent rotation relative to case body 110 when coupled to bolt 710. As a result, connecting portion 700 connects (joins) bus bar 420 and bus bar 460 .

[0048] The bus bar 430 is connected (joined) to the terminal 220 of the energy storage element 200 at the end in the negative Z-axis direction, which is located in the negative X-axis direction. The bus bar 430 comes into contact with the substrate 500 and is electrically connected to the substrate 500 (electrically connected to electrical components provided on the substrate 500), thereby electrically connecting to the bus bars 440 and 450 via the substrate 500. The bus bar 430 is fixed to the substrate 500 by a connection portion 600. The connection configuration of the bus bars 410 to 430 is not particularly limited, and any of the energy storage elements 200 may be connected in parallel. In the present embodiment, the bus bars 410 to 430 are joined to the terminal 220 by welding, but the terminal 220 may be a bolt terminal having a bolt portion (male thread portion) and may be bolted to the terminal 220, or the bus bars may be joined by other methods.

[0049] The bus bars 440 and 450 are electrically connected to the plurality of energy storage elements 200 via the bus bars 410 to 430 and the substrate 500. The bus bars 440 and 450 are arranged in positions where the substrate 500 is sandwiched between the bus bars 410 to 430. The bus bar 440 is arranged in the negative Y-axis direction of the substrate 500, and the bus bar 450 is arranged in the negative Y-axis direction of the bus bar 440. The bus bar 440 comes into contact with the substrate 500 and is electrically connected to the substrate 500 (electrically connected to the electrical components provided on the substrate 500). The bus bar 450 comes into contact with the bus bar 440 and is electrically connected to the bus bar 440. As a result, the bus bar 450 is electrically connected to the substrate 500 (electrically connected to the electrical components provided on the substrate 500). The bus bars 440 and 450 are fixed to the substrate 500 by the connection portions 600.

[0050] With this configuration, bus bar 460 is connected to bus bar 430 via bus bar 420, multiple energy storage elements 200, and bus bar 410, bus bar 430 is connected to substrate 500, substrate 500 is connected to bus bar 440, and bus bar 440 is connected to bus bar 450. Parts of bus bar 460 and bus bar 450 are exposed from outer case 100 and are connected to external conductive members (not shown).

[0051] Specifically, the bus bar 460 includes external terminal portions 461 and 462 that function as one of a positive external terminal and a negative external terminal, and the bus bar 450 includes external terminal portions 451 and 452 that function as the other of a positive external terminal and a negative external terminal. The external terminal portion 461 is fixed to the case body 110 while being exposed from the case recess 116 of the case body 110, and is a portion that is connected (contacted) with an external conductive member. The external terminal portion 462 is a member that connects (fixes) the external terminal portion 461 to the external conductive member. In the present embodiment, the external terminal portion 462 includes a male thread portion that is coupled with a nut (not shown) to connect (fix) the external terminal portion 461 to the external conductive member. The external terminal portion 462 may be formed of any material that can be used for the bus bar 400 described above, or may be formed of a metal such as stainless steel or iron, or a high-strength member other than a metal. The configuration of the external terminal portions 451 and 452 is the same as the configuration of the external terminal portions 461 and 462, and therefore detailed description thereof will be omitted. The energy storage device 10 is charged with electricity from the outside and discharges electricity to the outside via the bus bar 460 (external terminal portion 461) and the bus bar 450 (external terminal portion 451).

[0052] [1.5 Description of the Board 500] The board 500 is a circuit board electrically connected to the energy storage element 200 to monitor the charge or discharge state of the energy storage element 200 and control the charge and discharge of the energy storage element 200. The board 500 is a flat, rectangular member parallel to the XZ plane. The board 500 includes electrical components (all not shown) such as fuses, relays, semiconductor switches such as FETs (Field Effect Transistors), shunt resistors, thermistors, and connectors. The board 500 monitors the charge and discharge states of the energy storage element 200 and controls the charge and discharge of the energy storage element 200 by acquiring information such as the voltage of the energy storage element 200 via the bus bar 400 or a cable (not shown). The board 500 may also control the charge and discharge of the energy storage element 200 by acquiring temperature information of the energy storage element 200 via a thermistor (not shown). The substrate 500 may be configured to only monitor the state of the energy storage element 200 without controlling the charging and discharging of the energy storage element 200 .

[0053] The substrate 500 is disposed between the bus bars 410 to 430 and the bus bars 440 and 450, and is electrically connected to the bus bars 410 to 430 and the bus bars 440 and 450. The substrate 500 is fixed to the bus bars 430 and the bus bars 440 and 450 by connecting parts 600 between the bus bars 430 and the bus bars 440 and 450. Specifically, while the substrate 500 is fixed to the bus bars 430 and the bus bars 440 and 450, the substrate 500 is fixed to the inner case 300 by connecting parts 600 and is supported by the inner case 300.

[0054] [1.6 Description of Connection Portion 600] Connection portion 600 is disposed within outer case 100 and connects two components within outer case 100. The two components within outer case 100 may be two components at least partially disposed within outer case 100, and include bus bar 450, a portion of which (external terminal portions 451 and 452) is exposed from outer case 100. In the present embodiment, connection portion 600 connects inner case 300, bus bar 430, substrate 500, bus bar 440, and bus bar 450. In other words, connection portion 600 connects at least two components among inner case 300, bus bar 430, substrate 500, bus bar 440, and bus bar 450. It can also be said that connection portion 600 connects at least two components included in power storage device 10.

[0055] The connection part 600 includes a bolt 610 and a nut 620. The bolt 610 includes a head 611 and a shank 612. The head 611 is located at the end of the bolt 610 in the positive Y-axis direction and is a hexagonal column-shaped portion that is hexagonal when viewed in the Y-axis direction and flattened in the Y-axis direction. The shank 612 extends from the head 611 in the negative Y-axis direction and is a shaft body that includes a male thread. The nut 620 is a nut that includes a female thread to which the male thread of the shank 612 of the bolt 610 is coupled. The connection part 600 connects (joins) the inner case 300, the bus bar 430, the substrate 500, the bus bar 440, and the bus bar 450 by fixing the bolt 610 to the connection part 312 of the inner case 300 and coupling the bolt 610 to the nut 620. The structure of the connecting portions 600 and 312 connecting (joining) these members will be described in detail below with reference to FIGS. 4 and 5. FIG.

[0056] [2. Description of the Connection Configuration and Arrangement of the Connection Portions 600, 312] FIG. 4 is a cross-sectional view showing the connection configuration and arrangement of the connection portions 600, 312 according to this embodiment. FIG. 4 shows a cross-section of the energy storage device 10 shown in FIG. 1 cut along a plane parallel to the YZ plane passing through line IV-IV. FIG. 5 is a cross-sectional view and a front view showing an enlarged view of the connection configuration and arrangement of the connection portions 600, 312 according to this embodiment. FIG. 5(a) is a cross-sectional view showing an enlarged view of the connection portions 600, 312 and their surroundings shown in FIG. 4, and FIG. 5(b) is a front view showing the configuration when FIG. 5(a) is viewed from the front (negative Y-axis direction). In FIG. 5(b), the membrane member 130 is omitted from illustration.

[0057] 4 and 5 , head 611 of bolt 610 of connection portion 600 is inserted into connection portion 312 of inner case wall portion 310 of inner case 300 and connected (fixed) to connection portion 312. In this state, shaft portion 612 of bolt 610 penetrates bus bar 430, substrate 500, bus bar 440, and bus bar 450. The end of shaft portion 612 in the negative Y-axis direction is then coupled to nut 620.

[0058] Specifically, as shown in FIG. 3 , through-hole 431 is formed in bus bar 430 at a position overlapping with shaft portion 612 as viewed from the Y-axis direction. Through-hole 431 is a circular through-hole formed at the end of bus bar 430 in the positive X-axis direction and the positive Z-axis direction, and is larger in size than shaft portion 612 as viewed from the Y-axis direction. Through-hole 501 is formed in substrate 500 at a position overlapping with shaft portion 612 as viewed from the Y-axis direction. Through-hole 501 is a circular through-hole formed in the center of substrate 500 in the X-axis direction and the Z-axis direction, and is larger in size than shaft portion 612 as viewed from the Y-axis direction. Through-hole 441 is formed in bus bar 440 at a position overlapping with shaft portion 612 as viewed from the Y-axis direction. Through-hole 441 is a circular through-hole formed in the center of bus bar 440 in the X-axis direction and the Z-axis direction, and is larger in size than shaft portion 612 as viewed from the Y-axis direction. A through hole 453 is formed in bus bar 450 at a position overlapping with shaft portion 612 when viewed from the Y-axis direction. Through hole 453 is a circular through hole formed at the end of bus bar 450 in the negative X-axis direction, and is larger in size than shaft portion 612 when viewed from the Y-axis direction. Shank portion 612 is inserted into through hole 431 of bus bar 430, through hole 501 of substrate 500, through hole 441 of bus bar 440, and through hole 453 of bus bar 450, passing through them in the Y-axis direction, and is coupled to nut 620.

[0059] As a result, connecting portion 600, together with connecting portion 312, connects (joins) inner case 300, bus bar 430, substrate 500, bus bar 440, and bus bar 450 in this order. With this configuration, components inside outer case 100, such as energy storage element 200, bus bar 400, and substrate 500, are fixed inside outer case 100. In this manner, connecting portion 600, together with connecting portion 312, connects two components inside outer case 100. In other words, in the present embodiment, connecting portions 600 and 312 are examples of connecting portions that are disposed inside outer case 100 and connect two components inside outer case 100.

[0060] In this configuration, at least a portion of the connection portion 600 is disposed within the through hole 111a when viewed from the direction of penetration of the through hole 111a. That is, when the membrane member 130 is removed from the ventilation pipe 111b of the outer case 100 and the interior of the through hole 111a is viewed from the direction of penetration of the through hole 111a of the ventilation pipe 111b (the Y-axis direction), at least a portion of the connection portion 600 is visible. In this embodiment, the entire connection portion 600 (bolt 610 and nut 620) is disposed within the through hole 111a when viewed from the direction of penetration of the through hole 111a (the Y-axis direction). Similarly, at least a portion (in this embodiment, the entire connection portion 312) of the inner case 300 is disposed within the through hole 111a when viewed from the direction of penetration of the through hole 111a (the Y-axis direction). At least a portion (in this embodiment, all of) of through-hole 431 of bus bar 430 is disposed within through-hole 111a when viewed from the penetration direction (Y-axis direction) of through-hole 111a. The same applies to through-hole 501 of substrate 500, through-hole 441 of bus bar 440, and through-hole 453 of bus bar 450.

[0061] In this embodiment, the shaft 612 of the bolt 610 extends in the penetration direction of the through hole 111a (the Y-axis direction). Specifically, the central axis of the shaft 612 and the central axis of the through hole 111a coincide (are coaxial). It can also be said that the central axis of the connection portion 600 coincides (are coaxial) with the central axis of the through hole 111a. In other words, the connection portion 600 (bolt 610 and nut 620) is disposed at the center (center position) of the through hole 111a when viewed from the penetration direction of the through hole 111a (the Y-axis direction). Similarly, the central axis of the connection portion 312 coincides (are coaxial) with the central axis of the through hole 111a, and the connection portion 312 is disposed at the center (center position) of the through hole 111a when viewed from the penetration direction of the through hole 111a (the Y-axis direction). The central axis of through hole 431 of bus bar 430 and the central axis of through hole 111a are aligned (coaxial), and through hole 431 is disposed in the center (central position) of through hole 111a when viewed from the penetration direction (Y-axis direction) of through hole 111a. The same is true for through hole 501 of substrate 500, through hole 441 of bus bar 440, and through hole 453 of bus bar 450.

[0062] [3 Description of Effects] As described above, power storage device 10 according to the embodiment of the present invention is configured to allow ventilation between the inside and outside of outer case 100 via through-hole 111a in outer case 100. At least a portion of connection portion 600 or 312 connecting two components inside outer case 100 is disposed inside through-hole 111a when viewed from the direction of penetration of through-hole 111a. This allows access to connection portion 600 or 312 from through-hole 111a, using through-hole 111a that allows ventilation between the inside and outside of outer case 100. Therefore, power storage device 10 allows access to connection portion 600 or 312 connecting two components inside outer case 100 with a simple configuration.

[0063] If the connection portion 600 or 312 is accessible through the through-hole 111a, a tool (such as a socket or bit for screw or bolt fastening) can be inserted into the through-hole 111a to access the connection portion 600 or 312. This allows two components inside the outer case 100 to be connected with a simple configuration. By utilizing the through-hole 111a, which allows ventilation between the inside and outside of the outer case 100, there is no need to provide a lid to cover the through-hole 111a, reducing the number of components and eliminating the need for a process for attaching a lid to ensure airtightness. These factors facilitate the manufacture of the energy storage device 10 and reduce costs. Components inside the outer case 100, such as the connection portion 600 or a harness, can also be removed through the through-hole 111a.

[0064] The reason for providing through-hole 111a that allows ventilation between the inside and outside of outer case 100 (the reason for not covering through-hole 111a with an impermeable lid) is as follows: If outer case 100 were made of metal or otherwise strengthened so that it could withstand internal pressure, problems would arise, such as increased costs and an increased weight of outer case 100. For this reason, outer case 100 is made of resin or the like, and breathable membrane member 130 is provided to equalize the internal pressure of outer case 100 and the external pressure, thereby allowing ventilation between the inside and outside of outer case 100. If membrane member 130 were not provided, an excessive increase in internal pressure within outer case 100 could cause outer case 100 to crack in unintended locations, and therefore it would be necessary to design the outer case to reduce the amount of gas discharged from energy storage element 200.

[0065] In the present embodiment, since bus bar 450 is fixed (insert molded) to outer case 100, connecting bus bar 450 to bus bar 430 or the like inside outer case 100 cannot be achieved by a manufacturing method in which bus bar 450 is connected to bus bar 430 or the like and then disposed inside outer case 100. For this reason, through hole 111a is provided in outer case 100, and bus bar 450 is connected to bus bar 430 or the like from the outside of outer case 100 via connection portions 600, 312 through through hole 111a. This allows bus bar 450 to be connected to bus bar 430 or the like with a simple configuration. In other words, when connecting a component fixed to a separate component from outer case 100 to a component disposed inside outer case 100 with a large component such as substrate 500 sandwiched between them as in the present embodiment, it is more useful to configure outer case 100 so that ventilation between the inside and outside can be achieved via through hole 111a.

[0066] As with bus bar 450, bus bar 460 is fixed (insert molded) to case body 110 of outer case 100, and therefore, after being connected (fixed) to bus bar 420 by connecting portion 700, case lid 120 is attached to case body 110. Bus bar 460 may be connected to bus bar 420 in the same manner as bus bar 450. That is, bus bar 460 may be connected to bus bar 420 by, for example, providing a through-hole (not shown) in outer case 100 (case lid 120). In this case, the through-hole may be covered with a film member or closed with a small lid.

[0067] The connecting part 600 (bolt 610) has a shaft part 612 that extends in the direction of penetration of the through-hole 111 a. As a result, by accessing the connecting part 600 (shaft part 612 and nut 620) from the through-hole 111 a of the outer case 100, two components inside the outer case 100 can be connected by the shaft part 612 and the nut 620.

[0068] The outer case 100 is provided with a ventilation pipe 111b having a through hole 111a. This allows the connection part 600 or 312 to be accessed from the through hole 111a by using the through hole 111a of the ventilation pipe 111b provided in the outer case 100.

[0069] The outer case 100 is provided with a breathable membrane member 130 that covers the through-hole 111a, so that the connection portion 600 or 312 can be accessed from the through-hole 111a by using the through-hole 111a in which the membrane member 130 is disposed.

[0070] The membrane member 130 is attached to the outer surface of the outer case 100 (vent pipe 111b) around the through-hole 111a. This allows the connection portion 600 or 312 to be accessed through the through-hole 111a of the outer case 100, two components inside the outer case 100 to be connected, and then the membrane member 130 to be attached to the outer surface of the outer case 100 (vent pipe 111b), thereby facilitating the manufacture of the power storage device 10. Attaching the membrane member 130 to the outer surface of the outer case 100 (vent pipe 111b) facilitates visual inspection of the membrane member 130 from the outside, and maintenance work such as replacing or cleaning the membrane member 130. Attaching the membrane member 130 to the outer surface of the outer case 100 (vent pipe 111b) can prevent the membrane member 130 from peeling off or falling off due to an increase in external pressure of the outer case 100 or the impact of foreign objects such as water on the membrane member 130.

[0071] [4 Description of Modifications] While the energy storage device 10 according to the present embodiment has been described above, the present invention is not limited to the above embodiment. The embodiment disclosed herein is illustrative in all respects and is not restrictive, and the scope of the present invention includes all modifications within the meaning and scope of the claims.

[0072] (Variation 1) In the above embodiment, the connection portions 600, 312 connect the inner case 300, the bus bar 430, the substrate 500, the bus bar 440, and the bus bar 450, but it is sufficient if at least two of these members are connected. Fig. 6 is a cross-sectional view showing the connection configuration and arrangement positions of the connection portions 600, 312 provided in the energy storage device 11 according to Variation 1 of the present embodiment. Fig. 6 is a view corresponding to Fig. 5(a).

[0073] As shown in FIG. 6 , in this modification, the connection portions 600 and 312 connect the inner case 300 to the bus bar 430 and the bus bar 450. In this modification, the connection portions 600 and 312 are also disposed within the outer case 100 and are an example of connection portions that connect two components within the outer case 100. At least a portion of the connection portion 600 or 312 is disposed within the through hole 111a when viewed from the direction of penetration of the through hole 111a. The shaft portion 612 of the bolt 610 extends in the direction of penetration of the through hole 111a. The other configurations of this modification are the same as those of the above-described embodiment, and therefore detailed description thereof will be omitted. The same effects as those of the above-described embodiment can be achieved in this modification as well.

[0074] In this modification, the connection portions 600, 312 may connect only the inner case 300 and the bus bar 430, may connect only the inner case 300 and the board 500, or may connect only the inner case 300 and the bus bar 450. The connection portion 600 may connect only the bus bar 430 and the bus bar 450, may connect only the bus bar 430 and the board 500, or may connect only the bus bar 450 (and 440) and the board 500.

[0075] (Variation 2) In the above embodiment and Variation 1, the connection portions 600, 312 are configured to connect at least two of the inner case 300, bus bar 430, substrate 500, bus bar 440, and bus bar 450. However, any other components may be connected. The connection portions 600, 312 may connect the energy storage element 200 to another component, such as connecting the terminal 220 of the energy storage element 200 to the bus bar 400. The connection portions 600, 312 may connect two components not shown in the above embodiment and Variation 1, such as the connectors of two harnesses (such as a harness connected to the outside and an internal harness) located inside the outer case 100. In other words, the connection portions 600, 312 may connect any two components provided in the energy storage device. An example is shown below as Variation 2.

[0076] 7A and 7B are cross-sectional and front views showing the connection configuration and arrangement positions of the connection portions 630 and 322 included in the energy storage device 12 according to the second modification of this embodiment. (a) of FIG. 7A corresponds to FIG. 4, and (b) of FIG. 7B corresponds to FIG. 5B (the film member 130 is not shown in (b) of FIG. 7B). FIG. 8 is an exploded perspective view showing each component when the internal configuration of the outer case 100 of the energy storage device 12 according to the second modification of this embodiment is disassembled. Although FIG. 8 corresponds to FIG. 3, bus bars and the like are not shown, and the configuration of the energy storage elements 200, the support member 320, the substrate 500, and the connection portion 630 is shown.

[0077] 7 and 8 , in this modification, the connection portion 630 connects the support member 320 and the substrate 500. The connection portion 630 is a bolt having a shaft portion 631. The shaft portion 631 is a shaft body that extends in the positive direction of the Y axis and has a male thread portion.

[0078] The support member 320 is a plate-like member having a configuration similar to that of the inner case wall portion 310 of the inner case 300 in the above embodiment. That is, the support member 320 is provided with openings 321 into which the terminals 220 of the energy storage elements 200 are inserted, connection portions 322 to which the connection portions 630 are connected, and openings (not shown) through which gas discharged from the energy storage elements 200 passes. Although the support member 320 is provided with four openings 321, five openings 321 may be provided, similar to the openings 311 of the inner case wall portion 310, and the number, size, shape, etc. of the openings 321 are not particularly limited.

[0079] The connecting portion 322 is a portion to which the shaft portion 631 of the connecting portion 630 is connected. The connecting portion 322 is disposed at the center of the support member 320 in the X-axis direction and the Z-axis direction, and is a protruding portion that protrudes in the negative Y-axis direction. A female thread portion is formed in the center of the connecting portion 322, and the male thread portion formed on the shaft portion 631 is screwed into this female thread portion, thereby connecting (fixing) the connecting portion 630 to the connecting portion 322.

[0080] Specifically, the shaft 631 of the connecting portion 630 is inserted into the through-hole 501 (see FIG. 8 ) of the substrate 500 and penetrates the substrate 500 in the Y-axis direction. The shaft 631 is then coupled to the connecting portion 322. As a result, the connecting portion 630, together with the connecting portion 322, connects (joins) the substrate 500 and the support member 320. In other words, the connecting portion 630, together with the connecting portion 322, connects two components inside the outer case 100. In this way, in this modified example, the connecting portions 630 and 322 are an example of a connecting portion that is disposed inside the outer case 100 and connects two components inside the outer case 100.

[0081] In this configuration, at least a portion of the connecting portion 630 or 322 is disposed within the through hole 111a when viewed from the direction of penetration of the through hole 111a. In this modification, the entire connecting portion 630 and the connecting portion 322 are disposed within the through hole 111a when viewed from the direction of penetration of the through hole 111a (the Y-axis direction). The shaft portion 631 of the connecting portion 630 extends in the direction of penetration of the through hole 111a (the Y-axis direction). The central axes of the connecting portion 630 (shaft portion 631) and the connecting portion 322 are aligned (coaxial) with the central axis of the through hole 111a, and the connecting portion 630 and the connecting portion 322 are disposed in the center (central position) of the through hole 111a when viewed from the direction of penetration of the through hole 111a (the Y-axis direction). The other configurations of this modification are similar to those of the above-described embodiment, and therefore detailed description thereof will be omitted. This modification also achieves the same effects as the above-described embodiment.

[0082] In this modification, the support member 320 may be a part of a member similar to the inner case 300 in the above embodiment (a part corresponding to the inner case wall portion 310), or may be a bus bar holder that holds a bus bar, etc. The connection portion 630 may include a bolt and a nut, similar to the connection portion 600 in the above embodiment.

[0083] (Other Modifications) In the above embodiment, the membrane member 130 is attached to the outer surface of the outer case 100 (the outer surface of the ventilation pipe 111b), but it is sufficient that the membrane member 130 is disposed in a position that covers the through-hole 111a. The membrane member 130 may be attached to the inside of the ventilation pipe 111b or to the inner surface of the outer case 100 (the inner surface of the outer case side wall 111).

[0084] In the above embodiment, the energy storage device 10 includes the membrane member 130 and is configured to allow ventilation from the inside of the outer case 100 to the outside and from the outside to the inside via the through-hole 111a and the membrane member 130. However, this is not limiting. The energy storage device 10 may be configured to allow only ventilation from the inside of the outer case 100 to the outside (exhaust) or only ventilation from the outside to the inside (intake). The energy storage device 10 may not include the membrane member 130 and may be configured to allow ventilation between the inside and outside of the outer case 100 via the through-hole 111a. The membrane member 130 may not be breathable and may be a member that breaks and / or moves to open the through-hole 111a when the internal pressure of the outer case 100 becomes excessively high. That is, the energy storage device 10 may be provided with a valve member (pressure release valve, safety valve) that normally blocks the through-hole 111a and that allows ventilation between the inside and outside of the outer case 100 when the internal pressure of the outer case 100 increases, instead of or together with the membrane member 130. It can be said that the energy storage device 10 is configured such that ventilation between the inside and outside of the outer case 100 is possible via the through-hole 111a using this valve member as well.

[0085] In the above embodiment, the through-hole 111a (vent pipe 111b) is provided at the center in the X-axis direction and the center in the Z-axis direction of the outer case side wall 111 of the case main body 110, but this is not limited to this. As long as at least a portion of the connection portion 600 or 312 is positioned within the through-hole 111a when viewed from the penetration direction of the through-hole 111a, the through-hole 111a (vent pipe 111b) may be provided at any position on the outer case side wall 111. The through-hole 111a (vent pipe 111b) may be provided in any of the outer case side walls 112 to 114 and the outer case top wall 115 of the case main body 110, or may be provided in the case lid 120.

[0086] In the above embodiment, the outer case 100 (the outer case side wall 111 of the case main body 110) is provided with the vent pipe 111b, and the vent pipe 111b is provided with the through hole 111a, but the outer case 100 does not have to be provided with the vent pipe 111b. In this case, the through hole 111a may be a through hole formed in the outer case 100 (the outer case side wall 111 of the case main body 110, etc.).

[0087] In the above embodiment, the connection portion 312 is provided on the inner case wall portion 310 of the inner case 300, but the connection portion 312 may be provided on a flat plate-like member such as the support member 320 in the above-described modified example 2, or on a bus bar holder that holds the bus bar 400. In this case, the energy storage device 10 does not need to include the inner case 300.

[0088] In the above embodiment, the connecting portion 600 is fixed to the connecting portion 312 by being inserted (fitted) into the connecting portion 312, but the connecting portion 312 may be inserted (fitted) into the connecting portion 600 to fix the connecting portion 600 and the connecting portion 312. The connecting portion 600 and the connecting portion 312 may also be fixed by adhesion, welding, or the like.

[0089] In the above embodiment, when viewed from the direction of penetration of through hole 111a, the entire connecting portions 600 and 312 are arranged within through hole 111a, but only a portion of connecting portion 600 or 312 may be arranged within through hole 111a.

[0090] In the above embodiment, bolt 610 of connecting part 600 has shank 612 extending in the Y-axis direction, but shank 612 may extend in a direction different from the Y-axis direction, such as a direction inclined from the Y-axis direction, the X-axis direction, or the Z-axis direction. In this case, bolt 610 is coupled to nut 620 in a direction different from the Y-axis direction (the direction in which shank 612 extends) to connect two components inside outer case 100.

[0091] In the above embodiment, the connection portion 600 connects two components inside the outer case 100 by coupling the bolt 610 and the nut 620, but this is not limited thereto. The connection portion 600 may connect the two components by sandwiching them, may connect the two components by being fitted between them, or may connect the two components by engaging with them. The connection portion 600 may be an adhesive portion (adhesive, double-sided tape, etc.) when the two components are connected (joined) by bonding using an adhesive, double-sided tape, etc. The connection portion 600 is not a separate component from the two components, but may be a fitting portion when the two components are fitted together, or an engaging portion when the two components are engaged with each other. The connection portion 600 may be a welded portion (fused portion) when the two components are connected (joined) by welding such as laser welding, or a welded portion when the two components are connected (joined) by welding such as thermal welding. The connecting portion 600 may connect the two members by contacting them rather than by joining (fixing) them together. The contact may be for the purpose of preventing rotation or for electrical connection.

[0092] Any combination of the components included in the above-described embodiments and their modifications is also included within the scope of the present invention.

[0093] The present invention can be applied to an electricity storage device including an electricity storage element such as a lithium ion secondary battery.

[0094] REFERENCE SIGNS LIST 10, 11, 12 Energy storage device 100 Outer case 110 Case body 111, 112, 113, 114 Outer case side wall 111a, 421, 431, 441, 453, 463, 501 Through hole 111b Ventilation pipe 115 Outer case upper wall 116, 117 Case recess 120 Case lid 130 Membrane member 200 Energy storage element 210 Container 220 Terminal 300 Inner case 310 Inner case wall 311, 321 Opening 312, 322, 600, 630, 700 Connection 320 Support member 400, 410, 420, 430, 440, 450, 460 Bus bar 451, 452, 461, 462 External terminal portion 500: Circuit board 610, 710: Bolt 611: Head portion 612, 631: Shank portion 620, 720: Nut

Claims

1. An energy storage device including an energy storage element, comprising: a case that houses the energy storage element and has a through hole; and a connection portion that is disposed within the case and connects two components within the case, wherein the energy storage device is configured to allow ventilation between the inside and outside of the case through the through hole, and at least a portion of the connection portion is disposed within the through hole when viewed from the direction in which the through hole penetrates.

2. The energy storage device according to claim 1, wherein the connection portion includes an axis portion extending in the direction of penetration of the through hole.

3. The power storage device according to claim 1 or 2, wherein the case includes a vent pipe having the through hole.

4. The power storage device according to claim 1 or 2, wherein the case is provided with a membrane member that covers the through-hole and has air permeability.

5. The electricity storage device according to claim 4, wherein the membrane member is attached to the outer surface of the case around the through hole.

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