JP2024049801A - Power storage device - Google Patents

Abstract

[Problem] To provide an energy storage device capable of suppressing thermal effects on normal energy storage elements. [Solution] An energy storage device (10) includes a plurality of energy storage elements (11) each having a gas exhaust valve (111) and arranged with the gas exhaust valves (111) facing the same direction, and an exhaust section (50) disposed on each gas exhaust valve (111) of the plurality of energy storage elements (11) and forming an exhaust path (59) for gas exhausted from the gas exhaust valve (111). The exhaust section (50) includes a wall section (lid section (651)) that forms the exhaust path (59), and an exhaust port (51) that exhausts gas from the exhaust path (59) while being disposed outward of the plurality of energy storage elements (11) in the arrangement direction of the plurality of energy storage elements (11). The wall section has a through hole (653) that connects the inside of the exhaust section (50) to the outside of the energy storage device (10). [Selected Figure] FIG.

Description

The present invention relates to an electricity storage device.

Conventionally, in an energy storage device, an exhaust section (upper plate) is attached to a plurality of energy storage elements (secondary batteries) arranged in a predetermined direction (see, for example, Patent Document 1). The exhaust section forms an exhaust path for gas released from the gas exhaust valve (vent) of each energy storage element.

JP 2011-108653 A

If the storage element becomes excessively hot, high-temperature gas will be ejected from the gas exhaust valve. After all the gas has been ejected, high-temperature smoke will be emitted from the gas exhaust valve. This smoke does not have much force, so it may remain within the exhaust path. If the smoke remains within the exhaust path, it will cause the exhaust path to become hot, and this heat will be transferred to the normal storage element, potentially causing a thermal impact on the normal storage element.

Therefore, the object of the present invention is to provide an energy storage device that can suppress the thermal effects on normal energy storage elements.

In order to achieve the above object, a power storage device according to one aspect of the present invention is a power storage device comprising: a plurality of power storage elements, each having a gas exhaust valve, arranged with the gas exhaust valves facing the same direction; and an exhaust section disposed on the gas exhaust valve of each of the plurality of power storage elements and forming an exhaust path for gas exhausted from the gas exhaust valve, the exhaust section comprising a wall section forming the exhaust path and an exhaust port for exhausting the gas from the exhaust path, the wall section having a through hole connecting the inside of the exhaust section to the outside of the power storage device.

The energy storage device of the present invention can suppress the thermal effects on normal energy storage elements.

1 is a perspective view showing an external appearance of a power storage device according to an embodiment; FIG. 2 is an exploded perspective view showing each component of the electricity storage device according to the embodiment. FIG. 2 is an exploded perspective view showing a schematic configuration of an exhaust portion and a bus bar frame according to the embodiment. 10 is a top view showing the positional relationship between a through hole and a gas release valve of an energy storage element in the embodiment. FIG. 10 is an explanatory diagram showing a state in which gas is ejected from a gas exhaust valve of the energy storage element according to the embodiment. FIG. 10 is an explanatory diagram showing a state in which smoke is emitted from a gas exhaust valve of the energy storage element according to the embodiment. FIG. 13A and 13B are top views showing examples of positions at which through holes according to the modified example are provided.

(1) An energy storage device according to one aspect of the present invention is an energy storage device including a plurality of energy storage elements, each having a gas exhaust valve, arranged with the gas exhaust valves facing the same direction, and an exhaust section disposed on the gas exhaust valve of each of the plurality of energy storage elements and forming an exhaust path for gas exhausted from the gas exhaust valve, the exhaust section including a wall portion forming the exhaust path, and an exhaust port disposed outward from the plurality of energy storage elements in the arrangement direction of the plurality of energy storage elements, for exhausting the gas from the exhaust path, and the wall portion having a through hole connecting the inside of the exhaust section to the outside of the energy storage device.

According to this, the wall of the exhaust section is provided with a through hole that connects the inside of the exhaust section to the outside of the power storage device, and smoke can be exhausted through this through hole. This makes it possible to prevent the temperature in the exhaust path from increasing too high, and to suppress the amount of heat transferred to normal power storage elements. Therefore, the thermal impact on normal power storage elements can be reduced.

(2) In the energy storage device described in (1) above, the opening area of the through hole may be smaller than the opening area of the exhaust port.

With this, the opening area of the through hole is smaller than the opening area of the exhaust port, so that leakage of gas from the through hole during gas ejection can be suppressed. Therefore, gas can be more reliably discharged from the exhaust port.

(3) In the energy storage device described in (1) or (2) above, the through hole may be positioned so as not to overlap the gas exhaust valve in a plan view of the gas exhaust valve.

With this, the through hole is positioned so as not to overlap the gas exhaust valve in a plan view of the gas exhaust valve, so the gas exhausted from the gas exhaust valve does not go directly to the through hole. This makes it possible to further prevent gas from leaking out of the through hole.

(4) In the energy storage device described in any one of (1) to (3) above, the through hole may be disposed between the gas exhaust valves of a pair of adjacent energy storage elements among the plurality of energy storage elements.

With this, since the through hole is disposed between the gas exhaust valves of a pair of adjacent storage elements, the gas exhausted from the gas exhaust valve does not go directly to the through hole. Therefore, it is possible to further prevent gas from leaking out of the through hole.

(5) The energy storage device according to any one of (1) to (4) above may have a cover that covers the energy storage elements and the exhaust section, and the cover may have an opening that is connected to the through hole.

According to this, the cover that covers the multiple storage elements and the exhaust section has an opening that leads to the through-hole, so smoke can be discharged outside the cover through the through-hole and the opening. This makes it possible to prevent heat from building up inside the cover.

(Embodiment)
Hereinafter, a description will be given of an energy storage device according to an embodiment (including its modified example) of the present invention with reference to the drawings. Note that the embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components shown in the following embodiments are merely examples and are not intended to limit the present invention. In each drawing, the dimensions are not strictly illustrated.

In the following description and drawings, the width direction of the energy storage device, the arrangement direction of a pair of electrode terminals (positive and negative) in one energy storage element, and the direction in which the short sides of the container of the energy storage element face each other are defined as the X-axis direction. The longitudinal direction of the energy storage device, the arrangement direction of multiple energy storage elements, and the direction in which the long sides of the container of the energy storage element face each other are defined as the Y-axis direction. The height direction or the up-down direction of the energy storage device is defined as the Z-axis direction. These X-axis, Y-axis, and Z-axis directions intersect with each other (orthogonal in this embodiment). Depending on the mode of use, it is possible that the Z-axis direction is not the up-down direction, but for ease of explanation, the following description will be given assuming that the Z-axis direction is the up-down direction.

In the following description, for example, the positive X-axis direction indicates the direction of the X-axis arrow, and the negative X-axis direction indicates the opposite direction to the positive X-axis direction. The same applies to the Y-axis and Z-axis directions. In this embodiment, the positive Y-axis direction is backward, and the negative Y-axis direction is forward. Furthermore, expressions indicating relative directions or attitudes, such as parallel and perpendicular, also include cases where the directions or attitudes are not strictly those. For example, two directions being perpendicular not only means that the two directions are completely perpendicular, but also means that the directions are substantially perpendicular, that is, that there is a difference of, for example, about a few percent. Furthermore, in the following description, when the term "insulation" is used, it means "electrical insulation".

[Electricity storage device]
The configuration of the power storage device 10 according to the present embodiment will be described. Fig. 1 is a perspective view showing the external appearance of the power storage device 10 according to the embodiment. Fig. 2 is an exploded perspective view showing each component of the power storage device 10 according to the embodiment when disassembled.

The power storage device 10 is a device that can charge electricity from an external source and discharge electricity to the outside, and in this embodiment, has a substantially rectangular parallelepiped shape. For example, the power storage device 10 is a battery module (battery pack) used for power storage or power source applications. Specifically, the power storage device 10 is used as a battery for driving or starting the engine of a moving body such as an automobile, motorcycle, watercraft, ship, snowmobile, agricultural machinery, construction machinery, or a railway vehicle for an electric railway. Examples of the above-mentioned automobiles include electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and fossil fuel (gasoline, diesel, liquefied natural gas, etc.) vehicles. Examples of the above-mentioned railway vehicles for an electric railway include electric trains, monorails, linear motor cars, and hybrid trains 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.

As shown in Figures 1 and 2, the energy storage device 10 is a battery module (battery assembly) having a generally rectangular parallelepiped shape that is elongated in the Y-axis direction. Specifically, the energy storage device 10 has a plurality of energy storage elements 11, a bus bar frame 12, an exhaust section 50, a plurality of bus bars 13, and an exterior body 18 that houses these. The energy storage device 10 includes a cable 30 that forms part of the main circuit wiring and a detection line 13a. The energy storage device 10 may also have restraining members (end plates, side plates, etc.) that restrain the plurality of energy storage elements 11.

The storage element 11 is a secondary battery (single cell) that can charge and discharge electricity, and more specifically, is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. The storage element 11 has a flat rectangular parallelepiped shape (square shape), and in this embodiment, 16 storage elements 11 are arranged in the Y-axis direction. The shape, arrangement position, number, etc. of the storage elements 11 are not particularly limited. The storage element 11 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 may be a capacitor. The storage element 11 may be a primary battery instead of a secondary battery. Furthermore, the storage element 11 may be a battery using a solid electrolyte. The storage element 11 may be a pouch-type storage element.

Specifically, the energy storage element 11 includes a metal container 11a, and the upper wall 11d of the container 11a is provided with terminals 11b and 11c, which are metal electrode terminals. The terminal 11b is a positive terminal, and the terminal 11c is a negative terminal. The upper wall 11d of the container 11a is provided with a gas exhaust valve 111 between the terminals 11b and 11c, which exhausts gas and releases pressure when the pressure inside the container 11a rises. The energy storage element 11 has a flat rectangular parallelepiped shape whose thickness (dimension in the Y-axis direction) is smaller than its width (dimension in the X-axis direction), and the upper wall 11d has a rectangular shape when viewed from above (viewed in the Z-axis direction). The energy storage element 11 has a long side parallel to the XZ plane and a short side parallel to the YZ plane, and the long sides of the multiple energy storage elements 11 are arranged so that they face each other. The multiple energy storage elements 11 are arranged in a position in which the gas exhaust valves 111 face the same direction (Z-axis positive direction). A flat spacer 11e having thermal insulation properties is disposed between adjacent storage elements 11. The upper wall 11d of the container 11a may be provided with a liquid injection section for injecting an electrolyte. Inside the container 11a, electrodes (also called storage elements or power generation elements) and current collectors (positive and negative current collectors) are disposed, and an electrolyte (non-aqueous electrolyte) is enclosed, but a detailed description is omitted.

Here, the terminals 11b and 11c are arranged to protrude upward (in the positive direction of the Z axis) from the upper wall portion 11d of the container 11a. The outermost terminals 11b and 11c of the multiple storage elements 11 are connected to the cable 30, so that the storage device 10 can charge with electricity from the outside and discharge electricity to the outside.

The cable 30 is an electric wire (also called a power cable, power cable, power line, power line, or main circuit cable) through which current (also called charge/discharge current or main current) flows for charging and discharging the energy storage device 10 (energy storage elements 11), and has a positive power cable 31 for the positive pole and a negative power cable 32 for the negative pole. In other words, the positive power cable 31 of the cable 30 is connected to the terminal 11b of the energy storage element 11 at the end in the positive direction of the Y axis among the multiple energy storage elements 11, and the negative power cable 32 of the cable 30 is connected to the terminal 11c of the energy storage element 11 at the end in the negative direction of the Y axis.

The busbar frame 12 is a flat rectangular member that can electrically insulate the busbars 13 from other members and limit the position of the busbars 13. The busbar frame 12 is formed from an insulating member such as polycarbonate (PC), polypropylene (PP), or polyethylene (PE). Specifically, the busbar frame 12 is placed above the multiple energy storage elements 11 and positioned relative to the multiple energy storage elements 11. The multiple busbars 13 are placed and positioned on the busbar frame 12. As a result, each busbar 13 is positioned relative to the multiple energy storage elements 11 and joined to the terminals 11b and 11c of the multiple energy storage elements 11. The busbar frame 12 will be described in detail later.

The exhaust section 50 is disposed on the bus bar frame 12 and constitutes an exhaust path 59 (see FIG. 5, etc.) for the gas exhausted from the gas exhaust valve 111 of each storage element 11. One end of the exhaust section 50 in the positive Y-axis direction is an exhaust port 51 through which gas is exhausted, and protrudes from one end of the exterior body 18 in the positive Y-axis direction. Details of the exhaust section 50 will be described later.

Each bus bar 13 is a rectangular plate-like member arranged on the multiple storage elements 11 (on the bus bar frame 12) and electrically connects the electrode terminals of the multiple storage elements 11. The bus bar 13 is formed of a metal such as aluminum, aluminum alloy, copper, copper alloy, nickel material, etc. In this embodiment, the bus bar 13 connects the positive terminal (terminal 11b) and the negative terminal (terminal 11c) of the adjacent storage elements 11 to connect the 16 storage elements 11 in series. The multiple bus bars 13 are divided into a first bus bar group arranged along the Y axis direction on the positive side of the X axis (one side) and a second bus bar group arranged along the Y axis direction on the negative side of the X axis (the other side). Note that the connection of the storage elements 11 is not limited to the above, and any combination of series connection and parallel connection may be used.

A detection line 13a is connected to the bus bar 13 or the electrode terminal of the storage element 11. The connection structure is not shown. The detection line 13a is a cable for detecting the state of each storage element 11. The detection line 13a is an electric wire (also called a communication cable, control cable, communication line, or control line) for measuring the voltage or temperature of the storage element 11, or for balancing the voltage between the storage elements 11. A thermistor (not shown) for measuring the temperature of the storage element 11 is disposed on the bus bar 13 or the electrode terminal of the storage element 11, but the description thereof is omitted. A connector 13b is connected to the end of the detection line 13a in the negative Y-axis direction. The connector 13b is a connector that is connected to the board of the board unit (not shown).

The board unit is a device that can monitor the state of the storage elements 11 in the energy storage device 10 and control the storage elements 11. The board unit is attached to the longitudinal end of the energy storage device 10, i.e., the side surface of the energy storage device 10 facing the negative Y-axis direction. In this way, the detection line 13a transmits information such as the voltage and temperature of the storage elements 11 to the board of the board unit via the connector 13b. The detection line 13a also has the function of discharging the storage elements 11 with a high voltage by controlling the board, thereby balancing the voltage between the storage elements 11.

The exterior body 18 is a rectangular (box-shaped) housing (module case) that constitutes the exterior body of the energy storage device 10. In other words, the exterior body 18 is disposed outside the energy storage elements 11, etc., and fixes the energy storage elements 11, etc. in a predetermined position to protect them from impacts, etc. Here, the exterior body 18 has an exterior body main body 14 that constitutes the main body of the exterior body 18, an exterior body support 15 that supports the exterior body main body 14, and an exterior body lid 17 that constitutes the lid (outer lid) of the exterior body 18.

The exterior body 14 is a bottomed rectangular box-shaped housing with an opening formed on the top surface. The exterior body 14 is formed of an insulating material 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), polyether sulfone (PES), polyamide (PA), ABS resin, or a composite material thereof, or a metal with an insulating coating. This prevents the storage element 11 and the like from coming into contact with external metal members and the like. As long as the insulation of the storage element 11 and the like is maintained, the exterior body 14 may be formed of a conductive material such as a metal. The exterior body 14 houses multiple energy storage elements 11, an exhaust section 50, a bus bar frame 12, etc.

The bottom of the inside of the exterior body 14 is provided with a plurality of partition wall portions 142 that support the energy storage elements 11. The energy storage elements 11 are inserted and arranged between adjacent partition wall portions 142. This allows the energy storage elements 11 to be positioned at a predetermined interval. Note that other configurations may be used to support and position the energy storage elements 11 on the exterior body 14. The exterior body 14 also has side openings 143 on its side. These side openings 143 connect the space between the adjacent energy storage elements 11 to the space outside the energy storage device 10, contributing to cooling the energy storage device 10 including the energy storage elements 11. A notch 141 is formed at the end of the exterior body 14 on the positive Y-axis direction, at the center of the upper part, through which the exhaust port 51 of the exhaust unit 50 penetrates. The notch 141 is a rectangular notch with an open upper portion.

The exterior body support 15 and the exterior body lid 17 are exterior members that protect (reinforce) the exterior body main body 14. The exterior body support 15 and the exterior body lid 17 are formed from metal members such as stainless steel, aluminum, aluminum alloy, iron, plated steel sheet, etc. Note that the exterior body support 15 and the exterior body lid 17 may be formed from members of the same material or from members of different materials.

The exterior body support 15 is a member that supports the exterior body main body 14 from below (negative Z-axis direction) and has a bottom 15a, a board unit mounting portion 16, connection portions 15b and 15c, and a fixing portion 15d. The bottom portion 15a is a flat, rectangular portion that constitutes the bottom of the energy storage device 10, is parallel to the XY plane, and extends in the Y-axis direction, and is disposed below the exterior body main body 14.

The connection portion 15b is a flat, rectangular portion erected in the Z-axis positive direction from the end of the bottom portion 15a in the Y-axis negative direction toward the exterior body cover 17, and further has a protruding piece protruding in the Y-axis negative direction from the end of the Z-axis positive direction. The connection portion 15b is connected to the exterior body cover 17 at the protruding piece. The connection portion 15b forms part of the front side surface of the storage device 10. The connection portion 15c is a flat, rectangular portion erected in the Z-axis positive direction from the end of the bottom portion 15a in the Y-axis positive direction toward the exterior body cover 17, and further has a protruding piece protruding in the Y-axis positive direction. The connection portion 15c is connected to the exterior body cover 17 at the protruding piece. The connection portion 15c forms part of the rear side surface of the storage device 10.

The fixing portion 15d is a flat rectangular portion erected in the negative Z-axis direction from the end of the bottom portion 15a in the negative Y-axis direction, and is a protruding piece that fixes the storage device 10 to a structure such as a shelf (not shown). The fixing portion 15d is located in the center of the bottom portion 15a in the X-axis direction. In this embodiment, the fixing portion 15d is fixed to the shelf using screws, but any fixing method may be used as long as the fixing and release can be performed freely.

The exterior body cover 17 is a cover that covers the upper part of the multiple energy storage elements 11 and the exhaust section 50. Specifically, the exterior body cover 17 is a member that is arranged to cover the opening of the exterior body main body 14, and has a top plate portion 17a and connection portions 17b and 17c. The top plate portion 17a is a flat, rectangular portion that is parallel to the XY plane and extends in the Y-axis direction, constituting the upper surface portion of the energy storage device 10, and is arranged above the exterior body main body 14. A rectangular opening 171 that extends in the Y-axis direction is formed in the center of the top plate portion 17a in the X-axis direction. The opening 171 extends from the end of the top plate portion 17a in the negative Y-axis direction to the end in the positive Y-axis direction. This opening 171 exposes a part of the exhaust section 50 to the outside of the energy storage device 10.

The connection portion 17b is disposed at the end of the top plate portion 17a in the negative Y-axis direction, is bent toward the exterior body support 15, and has a protruding piece protruding in the negative Y-axis direction, and is connected to the connection portion 15b of the exterior body support 15. The connection portion 17c has a flat, rectangular portion erected in the negative Z-axis direction from the end of the top plate portion 17a in the positive Y-axis direction, and a protruding piece protruding in the positive Y-axis direction. The connection portion 17c is connected to the connection portion 15c of the exterior body support 15 at the protruding piece. The connection portion 17c forms a part of the rear side surface of the storage device 10. In this way, the exterior body support 15 and the exterior body cover 17 are configured to be fixed by connecting the connection portions 15b, 15c and the connection portions 17b, 17c to each other by screws or the like at the protruding pieces while sandwiching the exterior body main body 14 from above and below. As a result, each component housed within the exterior body 14 (bus bar frame 12, multiple energy storage elements 11, and exhaust section 50) is sandwiched vertically between the exterior body support 15 and the exterior body lid 17.

The connection portion 17c of the exterior body cover 17 has an exhaust port opening (not shown) formed in the center of the upper end portion (the end portion on the positive side of the Z axis) through which the exhaust port 51 of the exhaust unit 50 penetrates. The exhaust port opening has a shape in a plan view that corresponds to the external shape of the exhaust unit 50. The exhaust port 51 of the exhaust unit 50 protrudes from the exterior body 18 by penetrating the exhaust port opening and the cutout portion 141 of the exterior body main body 14.

The bus bar frame 12 is provided with electrically conductive parts such as the electrode terminals (terminals 11b, 11c) of the energy storage element 11, the bus bar 13, and the detection wire 13a. For this reason, an insulating plate may be provided on the back surface (lower surface) of the top plate portion 17a of the exterior body cover 17 to ensure electrical insulation with the exterior body cover 17, which is a metal part. The insulating plate may be screwed or attached to the top plate portion 17a.

[Busbar frame]
Next, the bus bar frame 12 will be described in detail. Fig. 3 is an exploded perspective view showing a schematic configuration of the exhaust unit 50 and the bus bar frame 12 according to the embodiment. Specifically, Fig. 3 is a perspective view of the exhaust unit 50 and the bus bar frame 12 as viewed from above.

As shown in FIG. 3, the busbar frame 12 is a frame-shaped member that is disposed on the multiple energy storage elements 11 and holds the multiple busbars 13. Specifically, the busbar frame 12 has a first holding portion 71, a second holding portion 72, and a connecting portion 73. Here, of the multiple detection lines 13a, the multiple detection lines 13a held by the first holding portion 71 are referred to as first detection lines. Of the multiple detection lines 13a, the multiple detection lines 13a held by the second holding portion 72 are referred to as second detection lines.

The first holding portion 71 is a portion on the X-axis positive side (one side) of the bus bar frame 12, and holds the first bus bar group, the positive power cable 31, and the multiple first detection lines. The multiple first detection lines are connected to the electrode terminals in the X-axis positive direction of each storage element 11 or to the bus bars 13 included in the first bus bar group.

The first holding portion 71 is disposed in the positive direction of the X-axis from the gas exhaust valve 111 of each storage element 11. The first holding portion 71 has a first outer wall portion 711 that surrounds the outer periphery of the first holding portion 71.

The first outer wall portion 711 is a frame wall that is long in the Y-axis direction and has a rectangular shape when viewed from above, and houses the first bus bar group, the positive power cable 31, and multiple first detection lines inside. A pair of first notches 711a, 711b are formed at the end of the first outer wall portion 711 in the negative Y-axis direction. One of the first notches 711a is arranged so that the positive power cable 31 and multiple first detection lines pass through it. The other first notch 711b is arranged so that the negative power cable 32 passes through it.

Within the first outer wall portion 711, the end region in the negative X-axis direction is a first cable path portion 715 that penetrates along the Y-axis direction. The first cable path portion 715 is disposed between the gas exhaust valve 111 of each storage element 11 and each bus bar 13 included in the first bus bar group. In this way, the first cable path portion 715 is disposed inward in the X-axis direction from the first bus bar group within the bus bar frame 12.

The positive power cable 31 and the multiple first detection lines are arranged in the first cable path section 715. The first cable path section 715 forms a wiring path for the positive power cable 31 and the multiple first detection lines. The multiple first detection lines and the positive power cable 31 are arranged in the first cable path section 715, so that they are arranged between the first holding section 71 and the second holding section 72, i.e., avoiding being located on the connecting section 73.

The second holding portion 72 is a portion of the busbar frame 12 on the negative X-axis side (the other side). The second holding portion 72 holds the second busbar group and the electrode terminals of each energy storage element 11 in the negative X-axis direction, or a plurality of second detection lines connected to the busbars 13 included in the second busbar group.

The second holding portion 72 is disposed in the negative X-axis direction relative to the gas exhaust valve 111 of each storage element 11. The second holding portion 72 has a second outer wall portion 721 that surrounds the outer periphery of the second holding portion 72.

The second outer wall portion 721 is a frame wall that is long in the Y-axis direction and has a rectangular shape when viewed from above, and houses a second bus bar group and multiple second detection lines inside. A second notch 721a is formed at the end of the second outer wall portion 721 in the negative Y-axis direction. The multiple second detection lines are arranged to pass through the second notch 721a.

The end region in the positive X-axis direction within the second outer wall portion 721 is a second cable path portion 725 that penetrates along the Y-axis direction. The second cable path portion 725 is disposed between the gas exhaust valve 111 of each storage element 11 and each bus bar 13 included in the second bus bar group. In this way, the second cable path portion 725 is disposed inward in the X-axis direction from the second bus bar group within the bus bar frame 12.

A plurality of second detection lines are arranged in the second cable path section 725. The plurality of second detection lines are arranged in the second cable path section 725, so that they are arranged between the first holding section 71 and the second holding section 72, i.e., avoiding being located on the connecting section 73.

The connecting portion 73 is a portion that connects the first holding portion 71 and the second holding portion 72. Specifically, the connecting portion 73 has a plurality of beam portions 731 extending in the X-axis direction, one end of which is connected to the first holding portion 71 and the other end of which is connected to the second holding portion 72. The plurality of beam portions 731 are arranged at a predetermined interval in the Y-axis direction. An exhaust portion 50 is arranged on the plurality of beam portions 731. Of the plurality of beam portions 731, the beam portion 731 at the end in the negative Y-axis direction is arranged outside the storage element 11 at the end in the negative Y-axis direction. The beam portion 731 at the end in the positive Y-axis direction is arranged outside the storage element 11 at the end in the positive Y-axis direction. The other beam portions 731 are arranged between a pair of adjacent storage elements 11. In this way, the plurality of beam portions 731 are arranged in a position retreated from the gas exhaust valve 111 of each storage element 11. In other words, the gas exhaust valve 111 of each energy storage element 11 is exposed between the multiple beam portions 731 when viewed from above.

[Exhaust section]
3, the exhaust unit 50 has an exhaust member 60 and a cover member 65. The exhaust member 60 and the cover member 65 form an exhaust path 59.

The exhaust member 60 is disposed directly above the gas exhaust valve 111 of each energy storage element 11 while being stored in the bus bar frame 12 as a whole. The exhaust member 60 includes a bottom wall portion 61 and a pair of first wall portions 62.

The bottom wall 61 is a rectangular wall parallel to the XY plane and extending in the Y-axis direction. In the center of the bottom wall 61 in the X-axis direction, a plurality of holes 611 are formed that expose the gas exhaust valves 111 of each storage element 11. Each hole 611 is a portion that introduces the gas and smoke exhausted from each gas exhaust valve 111 into the exhaust path 59.

The pair of first wall portions 62 are walls erected from both ends of the bottom wall portion 61 in the X-axis direction. The length of the exhaust member 60 in the Y-axis direction corresponds to the overall length of the exterior body main body 14 in the Y-axis direction. Therefore, the exhaust member 60 can be entirely contained within the exterior body main body 14. The exhaust member 60 is made of a highly heat-resistant resin, as it serves as the exhaust path 59 for the high-temperature gas and high-temperature smoke discharged from the energy storage element 11.

3, the cover member 65 is disposed above the exhaust member 60, blocks the open portion of the exhaust member 60, and covers the upper part of the exhaust path 59. Specifically, the cover member 65 is made of metal and has higher heat dissipation properties than the exhaust member 60. The cover member 65 is formed in a U-shape with an open lower end when viewed in the Y-axis direction, and is a long member in the Y-axis direction. The cover member 65 is housed within the exhaust member 60. The length of the cover member 65 in the Y-axis direction is longer than the total length of the exhaust member 60 in the Y-axis direction. Therefore, the other end of the cover member 65 in the positive Y-axis direction can be protruded from the exhaust member 60.

The other end of the lid member 65 in the positive Y-axis direction is open at the bottom and at the tip while protruding from the exhaust member 60. On the other hand, one end of the lid member 65 in the negative Y-axis direction is closed by a front wall 659. This front wall 659 is a flat, rectangular portion parallel to the XZ plane, and covers the base end 677 of the exhaust member 60 in the negative Y-axis direction from the outside. In other words, the front wall 659 of the lid member 65 and the base end 677 of the exhaust member 60 prevent gas leakage from the one end in the negative Y-axis direction, and gas can be reliably discharged from the exhaust port 51. The lid member 65, when housed in the exhaust member 60, constitutes a gas exhaust path 59 together with the exhaust member 60. Gas is discharged from the open portion at the other end of the lid member 65 described above. In other words, the other end of the lid member 65 is the exhaust port 51 through which gas is discharged. As a result, the exhaust port 51 is U-shaped when viewed in the gas travel direction (Y-axis direction). Specifically, the exhaust outlet 51 is U-shaped with the open portion facing downward. As described above, the exhaust outlet 51 in the lid member 65 protrudes from the exterior body 18 by penetrating the exhaust outlet opening of the exterior body lid 17 and the cutout portion 141 of the exterior body main body 14. Therefore, the exhaust outlet 51 is disposed outward from the multiple energy storage elements 11 in the arrangement direction (Y-axis direction) of the multiple energy storage elements 11.

The cover member 65 includes a cover portion 651 and a pair of second wall portions 652, which form a U-shaped outer shape when viewed in the Y-axis direction. The cover portion 651 is a wall portion with an open lower portion. The cover portion 651 is attached to the top plate portion 17a of the exterior body cover 17, and the cover member 65 and the exterior body cover 17 are integrated. The cover portion 651 has a plurality of through holes 653 that connect the inside of the exhaust portion 50 and the outside of the storage device 10. The plurality of through holes 653 are arranged along the Y-axis direction. Each through hole 653 is exposed from the top plate portion 17a by being disposed in the opening 171 of the top plate portion 17a. In other words, the opening 171 of the top plate portion 17a is spatially connected to each through hole 653. Each through hole 653 is exposed to the outside of the storage device 10 by the opening 171. As a result, each through hole 653 connects the inside of the exhaust section 50 (exhaust path 59) to the external space of the energy storage device 10.

FIG. 4 is a top view showing the positional relationship between the through hole 653 according to the embodiment and the gas exhaust valve 111 of the energy storage element 11. FIG. 4 is a plan view of the gas exhaust valve 111. In FIG. 4, one through hole 653 and a pair of adjacent energy storage elements 11 are illustrated, but the same is true for the other through holes 653 and the other pairs of adjacent energy storage elements 11. As shown in FIG. 4, in the plan view of the gas exhaust valve 111, the through hole 653 is arranged at a position that does not overlap with the gas exhaust valve 111. Specifically, the through hole 653 is arranged between the pair of adjacent energy storage elements 11. In other words, the through hole 653 is arranged on the beam portion 731 of the bus bar frame 12.

As shown in FIG. 3, the pair of second wall portions 652 extend downward from both ends of the cover portion 651 in the X-axis direction. Specifically, each second wall portion 652 is a plate-shaped rectangular wall portion parallel to the YZ plane and extending in the Y-axis direction. Each second wall portion 652 is accommodated so as to be adjacent to the pair of first wall portions 62 of the exhaust member 60 on the inside in the X-axis direction. In this state, the cover portion 651 of the cover member 65 is disposed above the pair of first wall portions 62 of the exhaust member 60. Therefore, the cover portion 651 of the cover member 65 is pressed downward by the top plate portion 17a of the exterior cover body 17. Due to this pressure, the pair of second wall portions 652 of the cover member 65 are pressed against the bottom wall portion 61 of the exhaust member 60. When gas is ejected from the gas exhaust valve 111 of the energy storage element 11, the cover member 65 may float because the cover member 65 receives the gas. Because the lid member 65 receives downward pressure from the exterior lid 17, it is possible to prevent the lid member 65 from floating due to the gas ejection.

[Explanation of when the gas exhaust valve is opened]
Next, a case where the gas exhaust valve 111 of the energy storage element 11 is opened will be described. When the energy storage element 11 becomes excessively hot, gas is generated inside the energy storage element 11, and the internal pressure rises. When the gas exhaust valve 111 opens due to the rise in internal pressure, gas is first ejected from the gas exhaust valve 111. FIG. 5 is an explanatory diagram showing a state in which gas is ejected from the gas exhaust valve 111 of the energy storage element 11 according to the embodiment. In FIG. 5, the gas is illustrated by arrows. This gas is introduced into the exhaust path 59 from the hole 611 of the exhaust section 50. As described above, since the through hole 653 of the cover member 65 is arranged at a position that does not overlap with the gas exhaust valve 111 in a plan view of the gas exhaust valve 111, the gas introduced into the exhaust path 59 from the hole 611 does not directly enter the through hole 653, but changes its direction by hitting the cover portion 651 of the cover member 65. As a result, the gas moves through the exhaust path 59 and is exhausted from the exhaust port 51. At this time, the gas flows vigorously through the exhaust path 59, so that it is difficult for the gas to leak out of the exhaust unit 50 from each through hole 653. Furthermore, since the opening area of one through hole 653 is smaller than the opening area of the exhaust port 51, it is possible to more reliably suppress the gas from leaking out of each through hole 653. The opening area of one through hole 653 is the area of the through hole 653 when the through hole 653 is viewed in a plane (viewed in the Z-axis direction). The opening area of the exhaust port 51 is the area of the exhaust port 51 when the exhaust port 51 is viewed in a plane (viewed in the Y-axis direction). When the total value of the opening areas of all the through holes 653 is A1 and the opening area of the exhaust port 51 is A2, it is preferable from the viewpoint of suppressing gas leakage that A1/A2<1/2.

When the gas is completely discharged from the gas discharge valve 111, smoke is generated from the gas discharge valve 111. FIG. 6 is an explanatory diagram showing a state in which smoke is discharged from the gas discharge valve 111 of the storage element 11 according to the embodiment. In FIG. 6, the smoke is illustrated by dot hatching. Since the smoke has a weaker momentum than the gas, it is difficult to move toward the exhaust port 51 and is likely to remain in the exhaust path 59. Since the smoke is hot, it gradually spreads along the upper part, that is, the lid portion 651, in the exhaust path 59 and reaches the through hole 653. As a result, the smoke is discharged from the through hole 653 to the outside of the exhaust unit 50. The smoke discharged to the outside of the exhaust unit 50 is discharged to the outside of the storage device 10 through the opening 171 of the exterior lid 17. This makes it possible to suppress the temperature rise in the exhaust path 59 caused by the smoke.

[Effects]
As described above, in the energy storage device 10 according to the present embodiment, the cover portion 651 (wall portion) of the exhaust portion 50 is provided with the through hole 653 that connects the inside of the exhaust portion 50 with the outside of the energy storage device 10, and therefore, smoke can be exhausted through the through hole 653. This makes it possible to prevent the inside of the exhaust path 59 from becoming too hot, and therefore to suppress the amount of heat transferred to the normal energy storage elements 11. Therefore, the thermal effect on the normal energy storage elements 11 can be suppressed.

The opening area of the through hole 653 is smaller than the opening area of the exhaust port 51, so that leakage of gas from the through hole 653 during gas ejection can be suppressed. Therefore, gas can be more reliably discharged from the exhaust port 51.

Since the through hole 653 is positioned so as not to overlap the gas exhaust valve 111 in a plan view of the gas exhaust valve 111, the gas exhausted from the gas exhaust valve 111 does not flow directly into the through hole 653. This makes it possible to further prevent gas from leaking out of the through hole 653.

Since the through-hole 653 is disposed between a pair of adjacent storage elements 11, the gas discharged from the gas exhaust valve 111 does not flow directly into the through-hole 653. This makes it possible to further prevent gas from leaking out of the through-hole 653.

The exterior body lid 17 (cover) that covers the multiple energy storage elements 11 and the exhaust section 50 has an opening 171 that is connected to the through hole 653, so smoke can be discharged outside the exterior body lid 17 through the through hole 653 and the opening 171. This makes it possible to prevent heat from building up inside the exterior body lid 17.

(others)
Although the power storage device 10 according to the above embodiment has been described above, the present invention is not limited to the above embodiment. The present invention is not limited to the above embodiment. The embodiment disclosed herein is illustrative and not restrictive in all respects, and the scope of the present invention includes all modifications within the meaning and scope equivalent to the claims. In the following description, the same parts as those in the above embodiment may be given the same reference numerals and their description may be omitted.

For example, in the above embodiment, a case where through holes 653 are provided between all pairs of adjacent storage elements 11 is illustrated. However, it is sufficient that at least one through hole is provided for the exhaust section.

In the above embodiment, the through hole 653 is disposed between a pair of adjacent storage elements 11. However, the through hole may be disposed at any location on the wall that constitutes the exhaust path. FIG. 7 is a top view showing an example of the location of the through hole according to the modified example. FIG. 7 is a view corresponding to FIG. 4. As shown in FIG. 7, the through hole may be disposed at the installation locations P1 and P2 that overlap the storage element 11 in a plan view of the gas exhaust valve 111 but do not overlap the gas exhaust valve 111. Even in this case, it is preferable that the gas ejected from the gas exhaust valve 111 does not go directly to the through hole. The through hole may be disposed at the installation location P3 that overlaps the gas exhaust valve 111 in a plan view of the gas exhaust valve 111.

In the above embodiment, a case where the through hole 653 is provided in the lid portion 651, which is an example of a wall portion that constitutes the exhaust path 59, has been illustrated. However, as long as the through hole leads to the outside of the power storage device, a through hole may be formed in other wall portions that constitute the exhaust path (such as the bottom wall portion and first wall portion of the exhaust member, the second wall portion and front wall portion of the lid member, etc.).

In the above embodiment, the exhaust section 50 is configured from two members, the exhaust member 60 and the cover member 65. However, the exhaust section may be configured from a single member, for example, a cylindrical member.

In the above embodiment, an exterior cover 17 having an opening 171 connected to the through hole 653 is given as an example of a cover. However, the cover does not have to have an opening. Even in this case, smoke can be discharged to the outside through the gap between the cover and other components.

The scope of the present invention also includes configurations constructed by arbitrarily combining the components of the above-described embodiment and its modified examples.

The present invention can be applied to energy storage devices equipped with energy storage elements such as lithium-ion secondary batteries.

10 Energy storage device 11 Energy storage element 11a Container 11b, 11c Terminal 11d Upper wall portion 11e Spacer 12 Bus bar frame 13 Bus bar 13a Detection line 13b Connector 14 Exterior body main body 15 Exterior body support 15a Bottom 15b, 15c, 17b, 17c Connection portion 15d Fixing portion 16 Board unit mounting portion 17 Exterior body lid (cover)
17a Top plate portion 18 Exterior body 30 Cable 31 Positive power cable 32 Negative power cable 50 Exhaust portion 51 Exhaust port 59 Exhaust path 60 Exhaust member 61 Bottom wall portion 62 First wall portion 65 Lid member 71 First holding portion 72 Second holding portion 73 Connection portion 111 Gas exhaust valve 141 Notch portion 142 Partition wall portion 143 Side opening portion 171 Opening 611 Hole portion 651 Lid portion (wall portion)
652 Second wall portion 653 Through hole 659 Front wall portion 677 Base end portion 711 First outer wall portions 711a, 711b First notch 715 First cable path portion 721 Second outer wall portion 721a Second notch 725 Second cable path portion 731 Beam portions P1, P2, P3 Installation location

Claims (5)

A plurality of electric storage elements each having a gas exhaust valve, the gas exhaust valves being arranged in such a manner that they face in the same direction;
an exhaust section disposed on the gas exhaust valve of each of the plurality of energy storage elements and forming an exhaust path for gas exhausted from the gas exhaust valve,
The exhaust section is
A wall portion that configures the exhaust path;
an exhaust port that exhausts the gas from the exhaust path in a state where the exhaust port is disposed outward of the plurality of energy storage elements in an arrangement direction of the plurality of energy storage elements,
the wall portion has a through hole connecting an inside of the exhaust portion to an outside of the power storage device. The power storage device according to claim 1 , wherein an opening area of the through hole is smaller than an opening area of the exhaust port. The power storage device according to claim 1 , wherein the through hole is disposed at a position not overlapping with the gas release valve in a plan view of the gas release valve. The energy storage device according to claim 1 , wherein the through hole is disposed between the gas release valves of a pair of adjacent energy storage elements among the plurality of energy storage elements. a cover for covering the plurality of power storage elements and the exhaust section,
The power storage device according to claim 1 , wherein the cover has an opening that is connected to the through hole.

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