Energy storage device

Abstract

To provide a power storage device with a simple configuration and improved safety.SOLUTION: A power storage device 1 includes a plurality of power storage elements 100, a gas discharge path forming member 250 forming a gas discharge path 254, and a partition wall portion 155. Each of the plurality of power storage elements 100 has a gas discharge valve 105 facing in a positive direction of a Z-axis, and they are arranged in an X-axis direction. The gas discharge path forming member 250 is arranged to face the plurality of gas discharge valves 105 in a positive direction of the Z-axis. The partition wall portion 155 is arranged between the gas discharge valves 105 of two adjacent power storage elements 100 among the plurality of power storage elements 100 when viewed from the positive direction of the Z-axis, and partitions two or more of the gas discharge paths 254 in the X-axis direction. The gas discharge path forming member 250 has a discharge portion 255 for discharging gas from the inside of the gas discharge path forming member 250 to the outside.SELECTED DRAWING: Figure 4

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a battery pack (power storage device) including a plurality of batteries (power storage elements). In this battery pack, each of the plurality of batteries is held by a battery holder. The battery holder includes a main body member that contacts the wide surface of the battery container, and an upper member having one end fixed to the upper end of the main body member and the other end contacting the upper surface of the battery container and extending in the thickness direction of the battery. The upper member is formed so as to surround the gas discharge valve of the battery and contacts the lower surface of the gas pipeline member to form a gas flow path from the gas discharge valve to the gas pipeline member.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In energy storage devices, if an abnormal external force is applied to the energy storage element in a manner not normally foreseen, the temperature inside the energy storage element may rise and gas may be generated. Since the internal pressure of the energy storage element may rise when gas is generated, the energy storage element is equipped with a gas discharge valve that opens to release the gas inside when the internal pressure of the energy storage element rises above a predetermined pressure. In the conventional energy storage device (battery pack) described in Patent Document 1, a gas pipeline member is positioned opposite the gas discharge valve of a plurality of energy storage elements (batteries) arranged in a row. When gas is discharged from the gas discharge valve of an energy storage element, the gas is guided into the gas pipeline member by an upper member arranged to surround the gas discharge valve. In this case, the pressure of the gas discharged from the gas discharge valve of one of the plurality of energy storage elements may affect all other energy storage elements through the gas pipeline member that forms a single gas discharge passage. Specifically, the pressure of gas discharged from the gas discharge valve of one energy storage element may cause the gas discharge valve of another energy storage element to open, potentially leading to the leakage of electrolyte from inside the energy storage element to the outside. To resolve this problem, one could consider placing a component (such as an exhaust pipe) that forms an individual gas discharge path for each of the multiple gas discharge valves. However, this would introduce another problem: the configuration of the energy storage device would become more complex.

[0005] This invention was made by the present inventor in response to the above-mentioned problems, and aims to provide an energy storage device with a relatively simple configuration and improved safety. [Means for solving the problem]

[0006] A power storage device according to one aspect of the present invention comprises a power storage element, a plurality of power storage elements arranged in a second direction intersecting the first direction, each having a gas discharge valve facing a first direction, a gas discharge path forming member that forms a gas discharge path and is arranged opposite the plurality of gas discharge valves in the first direction, and a partition wall portion that, when viewed from the first direction, is arranged between the gas discharge valves of two adjacent power storage elements among the plurality of power storage elements and divides the gas discharge path into two or more sections in the second direction, wherein the gas discharge path forming member has a discharge portion for discharging gas from the inside of the gas discharge path forming member to the outside. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an energy storage device with improved safety using a relatively simple configuration. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view showing the external appearance of the energy storage device according to the embodiment. [Figure 2] This is an exploded perspective view of the energy storage device according to the embodiment. [Figure 3] This is a perspective view showing the external appearance of the energy storage element according to the embodiment. [Figure 4] This is an exploded perspective view of the energy storage element unit according to the embodiment. [Figure 5] This is an exploded perspective view of the energy storage element array according to the embodiment. [Figure 6A] This is a perspective cross-sectional view of a gas discharge channel forming member according to an embodiment. [Figure 6B] This is a schematic diagram showing the position of the partition wall portion inside the gas discharge channel forming member according to the embodiment. [Figure 7] This is a perspective cross-sectional view showing the structural relationship between the gas discharge channel forming member and the partition wall according to the embodiment. [Modes for carrying out the invention]

[0009] A power storage device according to one aspect of the present invention comprises a plurality of power storage elements arranged in a second direction intersecting the first direction, each having a gas discharge valve facing a first direction; a gas discharge path forming member that forms a gas discharge path and is arranged opposite the plurality of gas discharge valves in the first direction; and a partition wall portion that, when viewed from the first direction, is arranged between the gas discharge valves of two adjacent power storage elements among the plurality of power storage elements and divides the gas discharge path into two or more sections in the second direction, wherein the gas discharge path forming member has a discharge portion for discharging gas from the inside of the gas discharge path forming member to the outside.

[0010] In this configuration, the gas discharge channel forming member is arranged to cover the gas discharge valves of two adjacent energy storage elements together, and the gas discharge channel inside the gas discharge channel forming member is partitioned between the two energy storage elements by a partition wall when viewed from the first direction. Therefore, the gas discharge channels for two adjacent energy storage elements can be formed relatively easily with a common gas discharge channel forming member, and the opening of the gas discharge valve of one of the two adjacent energy storage elements due to the pressure of the gas discharged from that valve can be suppressed. Furthermore, because the gas discharge channel forming member has a discharge section, the gas discharged from the energy storage elements and flowing into the gas discharge channel can be discharged to the outside of the gas discharge channel forming member via the discharge section. This allows the gas to be discharged to the outside of the gas discharge channel forming member while its temperature and velocity are reduced. Thus, according to this embodiment of the energy storage device, safety can be improved with a relatively simple configuration.

[0011] The gas discharge passage forming member may have a first wall portion that forms an inner surface of the gas discharge passage facing the plurality of energy storage elements in the first direction, and a second wall portion connected to the first wall portion that forms an inner surface of the gas discharge passage facing a third direction intersecting the first and second directions, and the discharge portion may be provided on the second wall portion.

[0012] According to this configuration, the discharge part, which is the outlet of the gas from the gas discharge passage, is provided in the second wall part that is not located in front of the gas discharge valve in the gas discharge passage forming member. Therefore, before the gas discharged from the gas discharge valve is discharged from the discharge part, the gas can be more reliably made to collide with the inner surface (first wall part) of the gas discharge passage forming member. As a result, the temperature and velocity of the gas can be more reliably reduced.

[0013] The discharge part may be an opening formed in a notch shape in the second wall part from an end close to the plurality of power storage elements in the first direction toward the first direction.

[0014] According to this configuration, the discharge part is provided in a notch shape from the edge of the second wall part, which is the side wall part of the gas discharge passage forming member. Therefore, while forming the overall shape of the gas discharge passage forming member by press working or casting or the like, the opening, which is the discharge part, can be formed. As a result, a gas discharge passage having the discharge part can be easily formed.

[0015] A first spacer having the partition wall part is disposed between the two power storage elements. The first spacer has a spacer main body located between the two power storage elements, and the partition wall part is provided so as to project from the spacer main body into the gas discharge passage.

[0016] According to this configuration, the partition wall part is provided as a part of the first spacer disposed between two adjacent power storage elements. Therefore, by combining the first spacer and the gas discharge passage forming member, a gas discharge passage having the partition wall part can be easily formed.

[0017] The power storage device may further include a second spacer that is disposed along the first spacer between the two power storage elements and has electrical insulation.

[0018] According to this configuration, the electrical insulation between the containers of two adjacent power storage elements can be entrusted to the second spacer. Therefore, the first spacer having the partition wall portion can be formed of a material with higher heat resistance than resin, such as metal or carbon fiber. As a result, the possibility that the partition wall portion is damaged by the heat of the gas is reduced, and as a result, the effect of partitioning the gas discharge path by the partition wall portion is more surely exhibited.

[0019] Hereinafter, a power storage device according to an embodiment (including its modification) of the present invention will be described with reference to the drawings. Each of the embodiments described below shows comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components, manufacturing processes, order of manufacturing processes, etc. shown in the following embodiments are examples and are not intended to limit the present invention. In each figure, dimensions and the like are not strictly illustrated. Further, in each figure, the same or similar components are denoted by the same reference numerals. Note that the names of the components (each component member) in the present embodiment are the names in the present embodiment and may be different from the names of the components (each component member) in the background art.

[0020] In the following description and drawings, the short-side direction of the exterior body of the power storage device or the opposing direction of the short side surfaces of the power storage elements is defined as the Y-axis direction. The longitudinal direction of the exterior body of the power storage device or the arrangement direction of a plurality of power storage elements is defined as the X-axis direction. The arrangement direction of the main body and the lid of the exterior body of the power storage device or the vertical direction is defined as the Z-axis direction. These X-axis direction, Y-axis direction, and Z-axis direction are directions that intersect (orthogonal in the present embodiment) with each other. Although the Z-axis direction may not be the vertical direction depending on the usage mode, hereinafter, for convenience of explanation, the Z-axis direction will be described as the vertical direction.

[0021] In the following description, for example, the X-axis plus direction indicates the arrow direction of the X-axis, and the X-axis minus direction indicates the direction opposite to the X-axis plus direction. The same applies to the Y-axis direction and the Z-axis direction. Simply referring to the "X-axis direction" means a bidirectional or one of the directions parallel to the X-axis. The same applies to the terms related to the Y-axis and the Z-axis.

[0022] Furthermore, expressions indicating relative directions or orientations, such as parallel and orthogonal, include cases where the directions or orientations are not strictly accurate. For example, two directions being orthogonal does not only mean that the two directions are perfectly orthogonal, but also that they are substantially orthogonal, meaning that there may be a difference of a few percent. In the following explanation, when the term "insulation" is used, it means "electrical insulation."

[0023] (Embodiment) [1. General explanation of energy storage devices] First, the general configuration of the energy storage device 1 according to the embodiment will be described. Figure 1 is a perspective view showing the external appearance of the energy storage device 1 according to the embodiment. Figure 2 is an exploded perspective view of the energy storage device 1 according to the embodiment. Figure 3 is a perspective view showing the external appearance of the energy storage element 100 according to the embodiment. Inside the outer casing 10, in addition to the components shown in Figures 2 and later, electrical equipment such as relays and control devices, as well as wiring connected to the electrical equipment, are housed, but the illustration and explanation of these components will be omitted as appropriate.

[0024] The energy storage device 1 is a device that can charge electricity from an external source and discharge electricity to the outside, and in this embodiment, it has a substantially rectangular parallelepiped shape. The energy storage device 1 is, for example, a battery module (battery pack) used for power storage or power supply purposes. Specifically, the energy storage device 1 is used as a battery for driving or starting the engine of mobile vehicles such as automobiles, motorcycles, watercraft, ships, snowmobiles, agricultural machinery, construction machinery, or railway vehicles for electric railways. Examples of 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 railway vehicles for electric railways include electric trains, monorails, linear motor cars, and hybrid trains equipped with both diesel engines and electric motors. The energy storage device 1 can also be used as a stationary battery for household or commercial use.

[0025] As shown in Figures 1 and 2, the energy storage device 1 comprises an outer casing 10 and an energy storage element unit 20 housed within the outer casing 10. Above the energy storage element unit 20 is a busbar holder 30 that holds the busbar 60 connected to the energy storage element 100. The outer casing 10 is a box-shaped (approximately rectangular parallelepiped) container (module case) that constitutes the housing of the energy storage device 1. The outer casing 10 is positioned outside the energy storage element unit 20 and the busbar holder 30, fixing them in place and protecting them from impacts and the like. The exterior body 10 is 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, or from metal with an insulating coating.

[0026] The exterior body 10 comprises an exterior body main body 12 and a cover 11. The exterior body main body 12 is a bottomed rectangular cylindrical housing with an opening 12a formed at the end in the Z-axis positive direction, and houses an energy storage element unit 20, etc. The cover 11 is a rectangular member that closes the opening 12a of the exterior body main body 12. The cover 11 is joined to the exterior body main body 12 by adhesive, heat sealing, ultrasonic welding, or laser welding, etc.

[0027] The cover 11 is provided with a pair of external terminals 19, which are a pair of module terminals for the positive and negative electrodes. The energy storage device 1 charges with electricity from the outside and discharges electricity to the outside through this pair of external terminals 19. The external terminals 19 are formed of a conductive metal such as aluminum, aluminum alloy, copper, or copper alloy. The cover 11 is further provided with an exhaust pipe 15 for guiding gas generated inside the outer casing 10 to the outside of the outer casing 10. For example, if one energy storage element 100 opens its valve and releases gas, the energy storage device 1 is designed to send that gas from inside the outer casing 10 to the outside via the exhaust pipe 15. More specifically, in this embodiment, the gas released from the energy storage element 100 is released from inside a gas discharge path forming member 250 arranged along the multiple energy storage elements 100, and then released to the outside of the outer casing 10 via the exhaust pipe 15. When the energy storage device 1 is installed in an automobile or the like, a gas hose (not shown) is connected to the exhaust pipe 15. This ensures that the gas discharged from the energy storage element 100 is guided to a predetermined location without affecting other components around the energy storage element 100 or the human body.

[0028] The energy storage element unit 20 includes an energy storage element array 101 containing a plurality of energy storage elements 100, and a restraining member 200 that restrains the energy storage element array 101. The energy storage element array 101 includes a plurality of energy storage elements 100 and cell holders 130 arranged along each of the plurality of energy storage elements 100. In this embodiment, the energy storage element array 101 has eight energy storage elements 100 and eight cell holders 130.

[0029] The energy storage element 100 is a secondary battery (single cell) capable of charging and discharging electricity. In this embodiment, the energy storage element 100 is a non-aqueous electrolyte secondary battery such as a lithium-ion secondary battery. As shown in Figure 3, the energy storage element 100 has a flat rectangular parallelepiped (square) container 110 and a pair of electrode terminals 120 (positive and negative electrodes) fixed to the container 110. Inside the container 110 are electrode bodies, current collectors, electrolytes, etc. (not shown). An example of an electrode body of the energy storage element 100 is a wound-type electrode body formed by winding together layers of electrodes arranged with a separator sandwiched between a positive electrode plate and a negative electrode plate. In addition, the energy storage element 100 may be equipped with a stacked type electrode body formed by stacking multiple flat electrode plates, or a bellows-type electrode body in which the electrode plates are folded in a bellows shape.

[0030] The energy storage element 100 is not limited to a non-aqueous electrolyte secondary battery, but may be a secondary battery other than a non-aqueous electrolyte secondary battery, or a capacitor. The energy storage element 100 may not be a secondary battery, but a primary battery that allows the user to use the stored electricity without charging. The energy storage element 100 may be a battery using a solid electrolyte. The energy storage element 100 may be a pouch-type energy storage element. Furthermore, the shape of the energy storage element 100 is not limited to the above-mentioned prismatic shape, but may be other shapes such as polygonal prisms, cylindrical shapes, elliptical prisms, or oblong cylindrical shapes.

[0031] In this embodiment, as shown in Figure 3, the container 110 has a pair of long sides 110a, a pair of short sides 110b, and a terminal arrangement surface 110c. The terminal arrangement surface 110c is the surface on which the positive and negative electrode terminals 120 are arranged. In this embodiment, a gas discharge valve 105 is further arranged on the terminal arrangement surface 110c. The gas discharge valve 105 is a part that opens (opens) when the internal pressure of the container 110 rises excessively, thereby discharging the gas inside the container 110 to the outside. In the energy storage element array 101, each of the multiple energy storage elements 100 is arranged in a posture in which the gas discharge valve 105 is oriented in the Z-axis positive direction and the long side 110a is oriented in the alignment direction (X-axis direction). In this embodiment, the Z-axis positive direction is an example of a first direction, and the X-axis direction is an example of a second direction that intersects the first direction.

[0032] The energy storage element array 101 configured in this way is constrained by a restraining member 200 in the direction of alignment of the multiple energy storage elements 100 (X-axis direction). The restraining member 200 has a pair of end members 210 arranged on both sides of the energy storage element array 101 in the X-axis direction, a pair of side members 220 arranged on both sides of the energy storage element array 101 in the Y-axis direction, and a gas discharge channel forming member 250 arranged in the Z-axis positive direction of the energy storage element array 101. In this embodiment, the gas discharge channel forming member 250 plays a role in connecting the pair of end members 210 in the X-axis direction and also plays a role in forming a gas discharge channel for gas discharged from the energy storage elements 100. The configuration of the gas discharge channel forming member 250 and its surroundings will be described later with reference to Figures 4 to 7.

[0033] The busbar holder 30 is a flat, rectangular insulating member positioned opposite the terminal arrangement surface 110c of the energy storage element 100, and holding a plurality of busbars 60 and electrical equipment (not shown). The busbar holder 30 may be formed from any electrically insulating resin material or the like that can be used for the casing 10. The busbar holder 30 may function as a restricting member that restricts the upward movement (in the positive Z-axis direction) of the plurality of energy storage elements 100 by contacting the terminal arrangement surface 110c of the plurality of energy storage elements 100 and being fixed to the casing 10. The busbars 60 positioned on the busbar holder 30 are positioned relative to the electrode terminals 120 to be joined, and in that state are joined to the electrode terminals 120 by laser welding or the like. In this embodiment, in the eight energy storage elements 100 of the energy storage element unit 20, two adjacent energy storage elements 100 are connected in parallel by busbars 60. This forms four sets of parallel-connected energy storage elements 100. Furthermore, the four sets of energy storage elements 100 are connected in series by three busbars 60. The electrical connection configuration of the eight energy storage elements 100 by the busbars 60 is not limited to this; for example, all eight energy storage elements 100 may be connected in series by multiple busbars 60. Also, the number of energy storage elements 100 in the energy storage element unit 20 is not limited to eight. The number of energy storage elements 100 in the energy storage element unit 20 can be two or more.

[0034] In the energy storage device 1 configured in this way, the gas discharge channel forming member 250, which is arranged as part of the restraining member 200, has a gas discharge channel divided into multiple sections inside. The configuration of this gas discharge channel forming member 250 and its surroundings will be described in detail below with reference to Figures 4 to 7.

[0035] [2. Regarding the gas discharge channel forming member and its surrounding structure] Figure 4 is an exploded perspective view of the energy storage element unit 20 according to the embodiment. Figure 5 is an exploded perspective view of the energy storage element array 101 according to the embodiment. Figure 6A is a perspective cross-sectional view of the gas discharge channel forming member 250 according to the embodiment. In Figure 6A, the gas discharge channel forming member 250 is shown in a state where it is cut along the line VI-VI in Figure 5. Figure 6B is a schematic diagram showing the position of the partition wall portion 155 inside the gas discharge channel forming member 250 according to the embodiment. Figure 7 is a perspective cross-sectional view showing the structural relationship between the gas discharge channel forming member 250 and the partition wall portion 155 according to the embodiment. The position of the cross section in Figure 7 corresponds to the position of the cross section in Figure 6A.

[0036] As shown in Figures 4 and 5, in the energy storage element unit 20, cell holders 130 are arranged on both sides of a pair of energy storage elements 100, which consist of two adjacent energy storage elements 100. In this embodiment, four groups of energy storage elements 100, each consisting of a pair of cell holders 130 and two energy storage elements 100 sandwiched between the pair of cell holders 130, are arranged in the X-axis direction. The cell holders 130 are an example of a second spacer and are made of resins such as PC, PP, PE, and PS, which were exemplified as materials for the exterior body 10 described above.

[0037] In this embodiment, the two energy storage elements 100 sandwiched between a pair of cell holders 130 are connected in parallel by a busbar 60. Therefore, even if the containers 110 of the two energy storage elements 100 are made of a conductive material such as metal, and no electrically insulating cell holders 130 are placed between the two energy storage elements 100, problems such as short circuits are unlikely to occur between the two energy storage elements 100.

[0038] In the energy storage element array 101, at positions where two cell holders 130 are aligned consecutively, an inter-cell plate 150 is positioned between the two cell holders 130, as shown in Figure 5. The inter-cell plate 150 is an example of a first spacer, and in this embodiment, it is made of a metal such as iron or an aluminum alloy. In this embodiment, the inter-cell plate 150 functions as a spacer that fills the space between two energy storage elements 100 located on either side of the inter-cell plate 150. In this embodiment, there are three positions in the energy storage element array 101 where two cell holders 130 are aligned consecutively in the X-axis direction, and therefore, three inter-cell plates 150 are included in the energy storage element array 101.

[0039] As described above, the energy storage element array 101, which has multiple energy storage elements 100, multiple cell holders 130, and multiple inter-cell plates 150, is constrained by the restraining member 200. Specifically, as shown in Figure 4, a pair of end members 210 facing each other in the X-axis direction are connected by a pair of side members 220 and a gas discharge channel forming member 250, thereby constraining the energy storage element array 101 in the X-axis direction. In this embodiment, the X-axis end of the side member 220 is joined to the Y-axis end of the end member 210 by two bolts 290. Specifically, two bolts 290, which are positioned to penetrate the X-axis end of the side member 220, are screwed into two nut portions 211 provided on the Y-axis end of the end member 210. The X-axis end of the gas discharge channel forming member 250 is joined to the Z-axis positive end of the end member 210 by one bolt 290. Specifically, a bolt 290, positioned to penetrate the X-axis end of the gas discharge passage forming member 250, is screwed into a nut portion 212 provided on the Z-axis positive end of the end member 210. With this configuration, the pair of end members 210 facing each other in the X-axis direction can firmly restrain the energy storage element array 101 sandwiched between the pair of end members 210 in the X-axis direction.

[0040] In this embodiment, the restraining member 200 is made of a metal such as iron or an aluminum alloy. The surface of the energy storage element array 101 facing the end member 210 is formed by a cell holder 130 located at the end of the energy storage element array 101. Therefore, the energy storage element array 101 and the end member 210 are insulated from each other by the cell holder 130 at the end. The cell holder 130 is a wall portion facing the short side surface 110b of the container 110, and has a wall portion located between the short side surface 110b and the side member 220. Therefore, the energy storage element array 101 and the side member 220 are insulated from each other by a plurality of cell holders 130.

[0041] In this embodiment, the gas discharge channel forming member 250 is located to the side of the energy storage element 100 in the Z-axis positive direction, as shown in Figures 4 and 5. Specifically, in the energy storage element row 101, the gas discharge channel forming member 250 is arranged to cover a plurality of gas discharge valves 105 that are oriented in the Z-axis positive direction and aligned in the X-axis direction. As shown in Figure 6A, the gas discharge channel forming member 250 has a first wall portion 251 and second wall portions 252 connected to both ends of the first wall portion 251 in the Y-axis direction. In other words, in the gas discharge channel forming member 250, a gas discharge channel 254 is formed by the space enclosed by the first wall portion 251 and the pair of second wall portions 252. In this embodiment, as shown in Figure 6B, the gas discharge channel 254 is divided into multiple sections in the X-axis direction by partition wall portions 155. Specifically, as shown in Figures 5 and 7, the partition wall portions 155 are arranged in the energy storage device 1 as part of the inter-cell plate 150. The inter-cell plate 150 has a plate body 151 located between two energy storage elements 100, and a partition wall portion 155 that protrudes from the plate body 151 in the positive Z-axis direction. The plate body 151 is an example of a spacer body of the first spacer. When the gas discharge passage forming member 250 is positioned relative to the energy storage element row 101, the partition wall portion 155 is inserted into the gas discharge passage 254 (see Figures 6A and 6B), as shown in Figure 7. As a result, the gas discharge passage 254 is partitioned by the partition wall portion 155 between two energy storage elements 100 located opposite each other with the inter-cell plate 150 in between.

[0042] For example, if we focus on the central intercellular plate 150 among the three intercellular plates 150, a storage element 100 (labeled as storage element 100A in Figure 5) is positioned on the side of the intercellular plate 150 in the positive X-axis direction. Another storage element 100 (labeled as storage element 100B in Figure 5) is also positioned on the side of the intercellular plate 150 in the negative X-axis direction. Thus, the partition wall portion 155 of the intercellular plate 150 located between storage elements 100A and 100B is positioned between the gas discharge valve 105 of storage element 100A and the gas discharge valve 105 of storage element 100B, and at this position, it divides the gas discharge passage 254 into two. In this embodiment, three such intercellular plates 150 having partition wall portions 155 are provided in the storage element array 101. As a result, as shown in Figure 6B, the single gas discharge channel 254 formed by the entire gas discharge channel forming member 250 is divided into four gas discharge channels 254 (gas discharge channels 254a, 254b, 254c, and 254d in Figure 6B).

[0043] In this embodiment, an outlet 255 is provided on the second wall portion 252 of the gas discharge passage forming member 250. When gas is discharged from the gas discharge valve 105, the gas flows into the gas discharge passage 254 and is discharged to the outside of the gas discharge passage forming member 250 from the outlet 255. More specifically, an outlet 255 is provided in each of the gas discharge passages 254a to 254d, which are formed by partitioning the gas discharge passage 254 with three partition walls 155. In Figures 5 to 6A, four outlets 255 are formed on the second wall portion 252 of the gas discharge passage forming member 250 in the negative Y-axis direction, but four outlets 255 may also be formed on the second wall portion 252 in the positive Y-axis direction. One or more outlets 255 may also be formed on both of a pair of opposing second wall portions 252 in the Y-axis direction.

[0044] For example, when the gas discharge valve 105 of the energy storage element 100A in Figure 5 is opened, the gas discharged from the energy storage element 100A flows into the gas discharge passage 254c in Figure 6B. The incoming gas is then discharged to the outside of the gas discharge passage forming member 250 from the discharge section 255 facing the gas discharge passage 254c. Subsequently, the gas is discharged to the outside of the outer casing 10 from the exhaust pipe 15 provided in the outer casing 10.

[0045] As described above, the energy storage device 1 according to this embodiment comprises a plurality of energy storage elements 100, a gas discharge passage forming member 250 that forms a gas discharge passage 254, and a partition wall portion 155. Each of the plurality of energy storage elements 100 has a gas discharge valve 105 facing the first direction, which is the Z-axis positive direction, and they are arranged in the X-axis direction intersecting the Z-axis positive direction. The gas discharge passage forming member 250 is positioned opposite the plurality of gas discharge valves 105 in the Z-axis positive direction. When viewed from the Z-axis positive direction, the partition wall portion 155 is positioned between the gas discharge valves 105 of two adjacent energy storage elements 100, and divides the gas discharge passage 254 into two or more sections in the X-axis direction. The gas discharge passage forming member 250 has a discharge portion 255 for discharging gas from the inside of the gas discharge passage forming member 250 to the outside.

[0046] As described above, in this embodiment, the gas discharge channel forming member 250 is arranged to cover the gas discharge valves 105 of two adjacent energy storage elements 100 (for example, energy storage elements 100A and 100B in Figure 5) collectively. Furthermore, the gas discharge channel 254 inside the gas discharge channel forming member 250 is partitioned between the energy storage elements 100A and 100B by a partition wall 155 when viewed from the Z-axis positive direction (hereinafter referred to as "plan view"). Therefore, the pressure of the gas discharged from one of the energy storage elements 100A and 100B's gas discharge valves 105 is unlikely to act on the other energy storage element 100A and 100B's gas discharge valve 105. This reduces the possibility of the other gas discharge valve 105 opening. In other words, the possibility of two adjacent energy storage elements 100 opening consecutively is reduced. Furthermore, because the gas discharge channel forming member 250 has a discharge section 255, the gas discharged from the energy storage element 100 and flowing into the gas discharge channel 254 can be discharged to the outside of the gas discharge channel forming member 250 via the discharge section 255. This allows the gas to be discharged to the outside of the gas discharge channel forming member 250 while its temperature and velocity are reduced. Therefore, the gas can be safely guided to a specified location, for example, via an exhaust pipe 15 provided in the outer casing 10. As a result, the occurrence of problems such as damage to the outer casing 10, which are likely to occur when gas is discharged from two or more energy storage elements 100, is suppressed. Thus, according to the energy storage device 1 of this embodiment, safety can be improved with a simple configuration.

[0047] In this embodiment, the gas discharge passage forming member 250 has a first wall portion 251 and a second wall portion 252. The first wall portion 251 forms the inner surface of the gas discharge passage 254 facing the plurality of energy storage elements 100 in the Z-axis positive direction. The second wall portion 252 is connected to the first wall portion 251 and forms the inner surface of the gas discharge passage 254 facing the Y-axis direction which intersects the Z-axis positive direction and the X-axis direction. The discharge portion 255 is provided in the second wall portion 252.

[0048] Thus, the discharge section 255, which is the outlet for the gas from the gas discharge passage 254, is provided on the second wall portion 252 of the gas discharge passage forming member 250, which is not located in front of the gas discharge valve 105. Therefore, the gas discharged from the gas discharge valve 105 can be more reliably made to collide with the inner surface (first wall portion 251) of the gas discharge passage forming member 250. This makes it possible to more reliably reduce the temperature and velocity of the gas.

[0049] As shown in Figures 4 to 6B, the discharge section 255 in this embodiment is an opening formed in the shape of a notch in the second wall section 252, extending in the positive Z-axis direction from the end closest to the multiple energy storage elements 100.

[0050] Thus, in this embodiment, the discharge section 255 is provided in a notched shape from the edge of the second wall portion 252, which is the side wall portion of the gas discharge passage forming member 250. Therefore, the opening which is the discharge section 255 can be formed at the same time as the overall shape of the gas discharge passage forming member 250 is formed by press working or casting. In other words, drilling or other operations on the second wall portion 252 are unnecessary.

[0051] In this embodiment, the partition wall portion 155 is realized by a part of a component separate from the gas discharge passage forming member 250. Specifically, an inter-cell plate 150 having a partition wall portion 155 is arranged between the two energy storage elements 100. The inter-cell plate 150 has a plate body 151 located between the two energy storage elements 100. The partition wall portion 155 is provided protruding from the plate body 151 into the interior of the gas discharge passage 254.

[0052] As described above, the partition wall portion 155 according to this embodiment is provided as part of the inter-cell plate 150, which is intended to restrict the positions of two adjacent energy storage elements 100 or to suppress the expansion of each of the two energy storage elements 100. Therefore, by arranging the gas discharge channel forming member 250 with respect to the energy storage element row 101 including the inter-cell plate 150, the arrangement of the partition wall portion 155 that partitions the gas discharge channel 254 is completed. Accordingly, there is no need to weld the member that functions as the partition wall portion 155, which is a separate member from the inter-cell plate 150, to the gas discharge channel forming member 250 or any other such work.

[0053] In this embodiment, in the energy storage element array 101, cell holders 130 are further arranged at the positions where the inter-cell plates 150 are placed. In other words, the energy storage device 1 includes cell holders 130 that are arranged along the inter-cell plates 150 between two energy storage elements 100 and have electrical insulating properties.

[0054] With this configuration, the insulation between the containers 110 of two adjacent energy storage elements 100 can be entrusted to the cell holder 130. Therefore, the inter-cell plate 150 having a partition wall 155 can be formed from a material with higher heat resistance than resin, such as metal or carbon fiber. In this embodiment, the inter-cell plate 150 is formed from a metal such as iron or aluminum alloy. This reduces the possibility of the partition wall 155 being damaged by the heat of the gas, and as a result, the effect of partitioning the gas discharge passage 254 by the partition wall 155 is more reliably achieved.

[0055] [3. Variant] Although an embodiment of the present invention, the energy storage device 1, has been described above, the present invention is not limited to this embodiment. In other words, the embodiments disclosed herein are illustrative and not restrictive in all respects, and the scope of the present invention includes all modifications in the sense and scope equivalent to the claims.

[0056] For example, the partition wall portion 155 does not need to be part of a separate component from the gas discharge channel forming member 250, such as the inter-cell plate 150. The partition wall portion 155 may be a component fixed to the gas discharge channel forming member 250, whose sole purpose is to partition the gas discharge channel 254. In this case, the partition wall portion 155 may be a component integrally provided with the gas discharge channel forming member 250 (part of the gas discharge channel forming member 250). The partition wall portion 155 may be a separate component from the gas discharge channel forming member 250, and may be a component joined to the gas discharge channel forming member 250 by welding or adhesive. In any case, the positioning of the partition wall portion 155 between the two gas discharge valves 105 in a plan view provides the effect of making it difficult for the pressure of the gas discharged from one gas discharge valve 105 to act on the other gas discharge valve 105.

[0057] The number of partition walls 155 arranged on the gas discharge channel forming member 250 is not limited to 3, but may be 2 or less, or 4 or more. As in the above embodiment, if the number of elements included in the energy storage element row 101 is 8, seven partition walls 155 may be arranged such that there is always one partition wall 155 between two adjacent gas discharge valves 105 in a plan view. Alternatively, one partition wall 155 may be arranged only between the two gas discharge valves 105 in the center of the eight gas discharge valves 105 arranged in the X-axis direction. In either case, focusing on one partition wall 155, there are at least two gas discharge channels 254 separated by the partition wall 155 inside the gas discharge channel forming member 250. Therefore, the effect is achieved that the gas pressure of one of the two gas discharge valves 105 located on either side of the partition wall 155 in a plan view is less likely to act on the other gas discharge valve 105.

[0058] When one partition wall portion 155 is arranged in the gas discharge channel forming member 250, the number of gas discharge channels 254 partitioned by the partition wall portion 155 may be three or more. For example, consider a case where there is a wall portion that protrudes in the negative Z-axis direction and is elongated in the X-axis direction at the center of the first wall portion 251 of the gas discharge channel forming member 250 in the Y-axis direction. In this case, as a result of the arrangement of a partition wall portion 155 parallel to the ZY plane that intersects with the elongated wall portion in the X-axis direction in the gas discharge channel forming member 250, four gas discharge channels 254 may be formed inside the gas discharge channel forming member 250.

[0059] When the partition wall portion 155 is positioned as part of the first spacer, the first spacer does not necessarily have to be the inter-cell plate 150. The first spacer having the partition wall portion 155 can be any member of a size and shape that fills at least a portion of the space between two energy storage elements 100 aligned in the X-axis direction. For example, a cell holder 130 may be provided in the energy storage device 1 as the first spacer having the partition wall portion 155. In this case, it is preferable that the cell holder 130 is made of a resin with high heat resistance. Furthermore, when the cell holder 130 is provided in the energy storage device 1 as the first spacer, the inter-cell plate 150 may be a second spacer positioned along the first spacer. The second spacer does not necessarily have a shape that holds the energy storage elements 100, like the cell holder 130. The second spacer positioned along the inter-cell plate 150, which is the first spacer, may be a simple flat member made of an insulating material.

[0060] The discharge portion 255 of the gas discharge channel forming member 250 does not need to be an opening provided in the shape of a notch from the edge of the second wall portion 252. The discharge portion 255 may be a through hole that penetrates the second wall portion 252 in the thickness direction (Y-axis direction). The discharge portion 255 may also be a part (for example, a thin-walled part) that is normally closed and forms an opening (through hole) by rupturing, breaking, or melting in response to an increase in internal pressure, such as the gas discharge valve 105 in the energy storage element 100. In other words, the discharge portion 255 only needs to be a part that can discharge the gas from the energy storage element 100 to the outside of the gas discharge channel forming member 250 through the gas discharge channel 254 when gas is discharged from the energy storage element 100. The discharge portion 255 may also be a part that is closed when gas is not being discharged from the energy storage element 100 (for example, an opening covered by a sheet-like member, or an opening sealed by an elastic member, etc.).

[0061] The location where the discharge section 255 is provided in the gas discharge channel forming member 250 does not necessarily have to be the second wall section 252. The discharge section 255 may be located on the first wall section 251. In this case, it is preferable that the discharge section 255 be located in a region of the first wall section 251 that does not face the gas discharge valve 105. This allows the gas discharged from the gas discharge valve 105 to be made to collide with the inner surface of the first wall section 251 before being discharged from the discharge section 255 to the outside of the gas discharge channel forming member 250. Therefore, the gas can be discharged to the outside of the gas discharge channel forming member 250 with a lower pressure and temperature than at the time of discharge from the gas discharge valve 105.

[0062] The gas discharge channel forming member 250 does not need to be part of the restraining member 200. The gas discharge channel forming member 250 may be a member arranged opposite to a plurality of gas discharge valves 105 and may not connect a pair of end members 210. In this case, the gas discharge channel forming member 250 may be, for example, part of the busbar holder 30, or it may be a separate member fixed to the busbar holder 30.

[0063] Furthermore, forms constructed by arbitrarily combining the components included in the above embodiments and their modified examples are also included within the scope of the present invention. [Industrial applicability]

[0064] This invention can be applied to energy storage devices equipped with energy storage elements such as lithium-ion secondary batteries. [Explanation of symbols]

[0065] 1. Energy storage device 100, 100A, 100B energy storage elements 101 Energy storage element array 105 Gas discharge valve 130 Cell Holder 150 inter-cell plate 151 Plate body 155 Partition wall section 200 Restraining member 210 End member 220 Side members 250 Gas discharge channel forming member 251 First wall 252 Second wall section 254, 254a, 254b, 254c, 254d Gas discharge channels 255 Discharge section

Claims

1. Each has a gas discharge valve facing a first direction, and a plurality of energy storage elements are arranged in a second direction intersecting the first direction, A gas discharge passage forming member, which forms a gas discharge passage, is arranged opposite to a plurality of gas discharge valves in the first direction, When viewed from the first direction, the gas discharge valves of two adjacent energy storage elements among the plurality of energy storage elements are arranged, and the gas discharge passage is divided into two or more sections in the second direction, and the partition wall portion is provided. The gas discharge channel forming member has a plurality of discharge sections for discharging gas from the inside to the outside of the gas discharge channel forming member. Each of the two or more discharge passages formed by partitioning the gas discharge passage with the partition wall is provided with one of the plurality of discharge sections. Each of the plurality of discharge sections is an opening provided in a region of the wall separating the inside and outside of the gas discharge passage forming member that does not face the gas discharge valve, and is an opening that penetrates the wall in the thickness direction of the wall. Energy storage device.

2. The wall portion of the gas discharge passage forming member has a first wall portion that forms the inner surface of the gas discharge passage facing the plurality of energy storage elements in the first direction, and a second wall portion connected to the first wall portion that forms the inner surface of the gas discharge passage facing a third direction intersecting the first and second directions. The discharge section is provided on the second wall portion, The energy storage device according to claim 1.

3. A plurality of energy storage elements, each having a gas discharge valve facing a first direction, and arranged in a second direction intersecting the first direction, A gas discharge passage forming member, which forms a gas discharge passage, is arranged opposite to a plurality of gas discharge valves in the first direction, When viewed from the first direction, the gas discharge valves of two adjacent energy storage elements among the plurality of energy storage elements are arranged, and the gas discharge passage is divided into two or more sections in the second direction, and the partition wall portion is provided. The gas discharge channel forming member has a discharge section for discharging gas from the inside of the gas discharge channel forming member to the outside. The gas discharge passage forming member has a first wall portion that forms the inner surface of the gas discharge passage facing the plurality of energy storage elements in the first direction, and a second wall portion that is connected to the first wall portion and forms the inner surface of the gas discharge passage facing a third direction intersecting the first and second directions. The discharge section is provided on the second wall section, The discharge portion is an opening formed in the second wall portion in a notched shape from the end closest to the plurality of energy storage elements in the first direction toward the first direction. Energy storage device.

4. A first spacer having the partition wall portion is placed between the two energy storage elements. The first spacer has a spacer body located between the two energy storage elements, The partition wall portion is provided so as to protrude from the spacer body into the gas discharge passage. The energy storage device according to any one of claims 1 to 3.

5. Furthermore, a second spacer is provided, which is positioned along the first spacer between the two energy storage elements and has electrical insulating properties. The energy storage device according to claim 4.

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