Energy storage device

Abstract

To provide a power storage device which is suppressed in increase of the size thereof and furthermore in which a plurality of power storage elements can be efficiently cooled.SOLUTION: A power storage device 1 comprises two power storage element units 30 arranged side by side in an X-axis direction, and a flow path forming member 50 which is disposed between the two power storage element units 30 and has a gas flow path extending in the Y-axis direction. Each of the two power storage element units 30 has a plurality of power storage elements 100 arranged in line in the Y-axis direction. The flow path forming member 50 has an opening 52 which allows gas to flow out from inside toward each of the two power storage element units 30.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a power storage device including a plurality of power storage elements.

Background Art

[0002] Patent Document 1 discloses a battery pack having a cooling structure. This battery pack includes a plurality of battery modules arranged in a row with a space therebetween in a space covered by a case body formed by combining two case pieces. The two case pieces have hollow ridges extending on the inner surface so as to contact the surface of the battery module and position the battery module in the space. The ridge is provided with through holes that communicate the inside and outside thereof. In this battery pack, the cooling air can be circulated into the space inside the case body through the through holes, so that mainly the side surfaces of the battery modules can be cooled.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Conventionally, in a power storage device including a plurality of power storage elements, for example, in order to suppress deterioration of the performance of each of the plurality of power storage elements, it is desirable to remove the heat of these plurality of power storage elements. In this regard, in the above conventional battery pack, a battery module, which is an aggregate of a plurality of cells (power storage elements), is arranged on a ridge provided on the inner bottom surface of the lower case piece, and a structure is adopted in which cooling air flows out from a through hole provided in the ridge. According to this structure, the battery module is cooled by the cooling air flowing out from the through hole of the ridge. However, since the battery module is supported by the ridge that contacts the bottom surface of the battery module, there is a problem that the size of the battery pack (power storage device) in the height direction increases.

[0005] This invention was made by the present inventors by newly focusing on the above-mentioned problems, and aims to provide an energy storage device that can efficiently cool multiple energy storage elements while suppressing an increase in size. [Means for solving the problem]

[0006] An energy storage device according to one aspect of the present invention comprises two energy storage element units, each having a plurality of energy storage elements arranged side by side in a first direction, the two energy storage element units arranged side by side in a second direction perpendicular to the first direction, and a flow path forming member disposed between the two energy storage element units and having a gas flow path inside that extends in the first direction, wherein the flow path forming member has an opening that allows the gas to flow out from inside toward each of the two energy storage element units. [Effects of the Invention]

[0007] The energy storage device according to the present invention allows for efficient cooling of multiple energy storage elements while suppressing an increase in size. [Brief explanation of the drawing]

[0008] [Figure 1] This is an exploded perspective view showing the configuration of the energy storage device according to the embodiment. [Figure 2] This is a perspective view showing the energy storage element unit and the outer casing body according to the embodiment. [Figure 3] This is an exploded perspective view of the array of energy storage elements in the energy storage element unit according to the embodiment. [Figure 4] This is a bottom view of a duct according to an embodiment. [Figure 5] This diagram shows the structural relationship between the holder and the energy storage element according to the embodiment. [Figure 6] This diagram shows the structural relationship between the duct, the two energy storage element units, and the exterior body according to the embodiment. [Figure 7]This is a perspective view showing a modified embodiment of the energy storage element unit and the outer casing body. [Figure 8] This is a perspective view of the exterior body according to a modified embodiment, as seen from diagonally below. [Figure 9] This figure shows the structural relationship between two energy storage element units and their exteriors, according to a modified embodiment. [Modes for carrying out the invention]

[0009] An energy storage device according to one aspect of the present invention comprises two energy storage element units, each having a plurality of energy storage elements arranged side by side in a first direction, the two energy storage element units arranged side by side in a second direction perpendicular to the first direction, and a flow path forming member disposed between the two energy storage element units and having a gas flow path inside that extends in the first direction, wherein the flow path forming member has an opening that allows the gas to flow out from inside toward each of the two energy storage element units.

[0010] In this configuration, for example, a flow channel forming member is placed between two energy storage element units arranged side by side, and the gas (such as cooling air) flowing out from this flow channel forming member can be directed to the two energy storage element units. Furthermore, because the flow channel forming member is positioned between the two energy storage element units, the increase in the vertical width (height) of the energy storage device due to the presence of the flow channel forming member is suppressed. Thus, the energy storage device according to this embodiment is an energy storage device that can efficiently cool multiple energy storage elements while suppressing an increase in size.

[0011] A first sealing member extending in the first direction may be positioned between the flow path forming member and each of the two energy storage element units.

[0012] In this configuration, the first sealing member prevents the gas supplied from the flow path forming member from leaking out between the flow path forming member and the energy storage element unit.

[0013] Each of the two power storage element units has the plurality of power storage elements with the electrode terminals of the plurality of power storage elements facing one side in a third direction orthogonal to the first direction and the second direction, and the flow path forming member may be disposed at an end portion on the one side in the third direction between the two power storage element units.

[0014] According to this configuration, when each of the two power storage element units has the plurality of power storage elements with the electrode terminals of the plurality of power storage elements facing upward, the flow path forming member can cause gas to flow out from an opening facing downward to the plurality of power storage elements. Thereby, for example, gas having a relatively high density due to a low temperature can be efficiently applied to the plurality of power storage elements. This is advantageous for efficient cooling of the two power storage element units.

[0015] Each of the two power storage element units has a plurality of holders that hold each of the plurality of power storage elements, the flow path forming member is disposed in contact with an end portion on the one side in the third direction of each of the plurality of holders of each of the two power storage element units, and the holder may have one or more groove portions that allow the gas to pass therethrough in the second direction.

[0016] According to this configuration, each of both end portions in the second direction of the flow path forming member is in a state of being supported by the plurality of holders. Thereby, the flow path forming member can be stably supported, and the flow path forming member is less likely to be affected by heat from the power storage element. Further, since the holder has a groove portion that allows gas to pass therethrough in the second direction, the gas from the flow path forming member supplied from one side in the second direction can be circulated to the other side in the second direction. Thereby, the power storage element held by the holder can be cooled in a wide range in the second direction.

[0017] The two power storage element units are arranged on the bottom wall portion of the exterior body that houses the two power storage element units and the flow path forming member, and a second sealing member is arranged between the bottom surface of each of the two power storage element units and the bottom wall portion at the end closer to the other power storage element unit among both end portions in the second direction. This can also be adopted.

[0018] According to this configuration, the airtightness of the space between the two power storage element units and between the flow path forming member and the bottom wall portion of the exterior body is improved. Thereby, the gas supplied to the space can be efficiently sent out toward the power storage element units on both sides of the space.

[0019] A third sealing member may be arranged between the bottom surface of each of the two power storage element units and the bottom wall portion at the end farther from the other power storage element unit among both end portions in the second direction.

[0020] According to this configuration, the airtightness of the space outside the two power storage element units is improved. Thereby, for example, the gas after heat exchange with the power storage element unit can be efficiently guided to a predetermined outlet (discharge port). That is, the occurrence of a state where the gas that has undergone heat exchange with the power storage element unit stays wastefully is suppressed.

[0021] The flow path forming member is a partition wall portion that is arranged between the two power storage element units and partitions the two power storage element units, and is a partition wall portion formed by a part of the exterior body that houses the two power storage element units. The opening includes a first opening formed in a first inner wall portion of the partition wall portion facing one of the two power storage element units, and a second opening formed in a second inner wall portion of the partition wall portion facing the other of the two power storage element units. This can also be adopted.

[0022] According to this configuration, gas can be made to flow out from the partition wall portion that partitions the two power storage element units toward the power storage element units on both sides thereof. Therefore, a power storage device with good space efficiency can be realized.

[0023] The partition wall portion is provided projecting between the two energy storage element units from the bottom wall portion where the two energy storage element units are arranged, and the bottom wall portion may have a bottom wall opening on the surface opposite to the projection direction of the partition wall portion that communicates with the interior of the partition wall portion.

[0024] In this configuration, the partition wall is part of the bottom wall and is formed as a curved portion that protrudes toward the interior of the outer casing. Therefore, the partition wall can be manufactured by methods such as casting, pressing, or machining from the back surface of the bottom wall. As a result, an outer casing equipped with a partition wall having a gas flow path extending in the first direction can be manufactured relatively easily. Furthermore, since the bottom wall opening is formed on the back surface of the bottom wall, the bottom wall opening can be closed by, for example, an installation surface on which a power storage device is installed. As a result, leakage of gas from inside the partition wall through the bottom wall opening is suppressed.

[0025] The exterior body may further include a gas inlet formed in the first end wall on one side of the first direction, connecting the outside of the exterior body with the inside of the partition wall, and a gas outlet formed in the second end wall on the other side of the first direction, connecting the space outside the partition wall and inside the exterior body with the outside of the exterior body.

[0026] In this configuration, the gas supplied from one side in the first direction to the partition wall, which functions as a flow path forming member, exchanges heat with the two energy storage element units and is then discharged to the outside of the outer casing through an outlet provided on the other side in the first direction. This allows for smoother circulation of the gas used to cool the two energy storage element units. As a result, for example, the amount of cooling gas supplied to the two energy storage element units per unit time can be increased.

[0027] The following description of an energy storage device according to an embodiment (including its modifications) of the present invention will be given with reference to the drawings. The embodiments described below are all general or specific examples. The numerical values, shapes, materials, components, arrangement and connection configurations of components, manufacturing processes, and the order of manufacturing processes shown in the following embodiments are examples and are not intended to limit the present invention. Dimensions and other specifications are not strictly illustrated in each figure. In each figure, the same or similar components are denoted by the same reference numerals.

[0028] In the following description and drawings, the direction in which the pair of electrode terminals of an energy storage element are aligned, the direction in which the pair of short sides of the energy storage element container are aligned, or the direction in which the energy storage element unit is aligned is defined as the X-axis direction. The direction in which the pair of long sides of the energy storage element container are aligned, the thickness direction (flattening direction) of the energy storage element container, the direction in which the multiple energy storage elements of an energy storage element unit are aligned, or the direction in which the energy storage elements of an energy storage element unit are aligned with the holder is defined as the Y-axis direction. The direction in which the array of energy storage elements of an energy storage element unit is aligned with the busbar plate, the direction in which the container body and the container lid of the energy storage element are aligned, the direction in which the outer casing body and the lid of the outer casing body are aligned, or the vertical direction is defined as the Z-axis direction. These X-axis, Y-axis, and Z-axis directions intersect (orthogonal in this embodiment) with each other. Depending on the usage, the Z-axis direction may not be the vertical direction, but for the sake of explanation below, the Z-axis direction will be described as the vertical direction.

[0029] In the following explanation, the X-axis positive direction refers to the direction of the X-axis arrow, and the X-axis negative direction refers to the opposite direction. When simply referring to the X-axis direction, it refers to either the X-axis positive direction or the X-axis negative direction, or either direction. When referring to one side and the other side of the X-axis direction, it refers to one and the other of the X-axis positive direction and the X-axis negative direction. The same applies to the Y-axis direction and the Z-axis direction. In the following, the Y-axis direction will also be called the first direction, the X-axis direction the second direction, and the Z-axis direction the third direction. Expressions indicating relative directions or orientations, such as parallel and orthogonal, include cases where they are not strictly those directions or orientations. For example, when two directions are parallel, it means not only that the two directions are perfectly parallel, but also that they are substantially parallel, i.e., that they include a difference of, for example, a few percent. In the following explanation, when the term "insulation" is used, it means "electrical insulation".

[0030] (Embodiment) [1. General explanation of energy storage devices] First, the general configuration of the energy storage device 1 according to the embodiment will be explained using Figures 1 to 3. Figure 1 is an exploded perspective view showing the configuration of the energy storage device 1 according to the embodiment. In Figures 1 and subsequent figures, the busbars connected to one or more energy storage elements 100 are not shown. Figure 2 is a perspective view showing the energy storage element unit 30 and the outer casing body 310 according to the embodiment. Figure 3 is an exploded perspective view of the energy storage element array 10 of the energy storage element unit 30 according to the embodiment. In Figure 3, some of the energy storage elements 100 and holders 200 of the energy storage element array 10 are shown separated in the direction of their arrangement (Y-axis direction).

[0031] The energy storage device 1 is a device that can charge electricity from an external source and discharge electricity to an external source. The energy storage device 1 is used for power storage or power supply purposes. 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, maglev trains, 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.

[0032] As shown in Figure 1, the energy storage device 1 comprises an energy storage element unit 30, a flow path forming member 50, and an outer casing 300 that houses the flow path forming member 50 and the energy storage element unit 30. In this embodiment, a long duct 50a in the Y-axis direction is used as the flow path forming member 50. The flow path forming member 50 is a member having a gas flow path extending in the Y-axis direction inside, and the two energy storage element units 30 are cooled by this gas. Details of the flow path forming member 50 and related configurations will be described later with reference to Figures 4 to 6. The energy storage device 1 also includes external terminals (positive electrode external terminal and negative electrode external terminal) for electrical connection to external devices, but their illustration and description are omitted. In addition to the above components, the energy storage device 1 may also include a circuit board and electrical equipment such as relays for monitoring or controlling the charging and discharging states of the energy storage element unit 30, either mounted inside or outside the outer casing 300.

[0033] The energy storage element unit 30 is a battery module (battery pack) having a plurality of energy storage elements 100. The energy storage element unit 30 has an array of energy storage elements 10 and a busbar plate 20 positioned above the array of energy storage elements 10 (in the positive Z-axis direction).

[0034] The energy storage element array 10 has a roughly rectangular parallelepiped shape that is elongated in the Y-axis direction, as multiple energy storage elements 100 are arranged alternately with the holder 200 in the Y-axis direction. The Y-axis direction is one example of the first direction. The energy storage element 100 is a secondary battery (single cell) that can charge and discharge electricity, and more specifically, a non-aqueous electrolyte secondary battery such as a lithium-ion secondary battery. The energy storage element 100 has a flattened rectangular parallelepiped shape (square) in the Y-axis direction.

[0035] As shown in Figure 3, the energy storage element 100 has a container 110 and a pair of electrode terminals 140 (positive and negative). Inside the container 110 are the electrode body, the pair of current collectors (positive and negative), and the electrolyte (non-aqueous electrolyte). There are no particular restrictions on the type of electrolyte, as long as it does not impair the performance of the energy storage element 100, and various types can be selected. In addition to the above components, the energy storage element 100 may also have spacers placed on the sides of the electrode body, an insulating film that encloses the electrode body, etc., and an insulating film (shrink tubing, etc.) that covers the outer surface of the container 110.

[0036] The container 110 is a rectangular parallelepiped (square or box-shaped) container having a container body 120 with an opening and a container lid 130 that closes the opening of the container body 120. The container body 120 is a rectangular cylindrical member with a bottom that constitutes the main body of the container 110, and has an opening formed at the end in the positive Z-axis direction. The container lid 130 is a rectangular plate-shaped member that is elongated in the X-axis direction and constitutes the lid of the container 110, and is positioned in the positive Z-axis direction of the container body 120. The X-axis direction is an example of a second direction perpendicular to the first direction. The container lid 130 is provided with a gas discharge valve 131 that releases pressure when the pressure inside the container 110 rises excessively, and an injection part (not shown) for injecting electrolyte into the container 110. The material of the container 110 (container body 120 and container lid 130) is not particularly limited and can be made of weldable (joinable) metals such as stainless steel, aluminum, aluminum alloy, iron, plated steel sheet, etc., but resin can also be used.

[0037] The container 110 is sealed inside by welding or other means after the electrode body and other components are placed inside the container body 120, and the container body 120 and the container lid 130 are joined together. The container 110 has a pair of long sides 111 on both sides in the Y-axis direction, a pair of short sides 112 on both sides in the X-axis direction, and a bottom surface 113 in the Z-axis direction opposite to the container lid 130. The Z-axis direction is an example of a third direction perpendicular to the first and second directions. The long sides 111 are adjacent to the short sides 112 and the bottom surface 113 and have a larger area than the short sides 112. The short sides 112 are adjacent to the long sides 111 and the bottom surface 113 and have a smaller area than the long sides 111. The bottom surface 113 is a rectangular flat surface that forms the bottom of the container 110. The bottom surface 113 is positioned adjacent to the long sides 111 and the short sides 112.

[0038] The electrode terminals 140 are terminal members (positive and negative electrode terminals) of the energy storage element 100, located on the container lid 130. Specifically, the electrode terminals 140 are positioned so as to protrude in the positive Z-axis direction from the upper surface (terminal placement surface) of the container lid 130. The electrode terminals 140 are electrically connected to the positive and negative electrode plates of the electrode body via a current collector. The electrode terminals 140 are made of aluminum, aluminum alloy, copper, copper alloy, or the like.

[0039] The electrode body is an energy storage element (power generation element) formed by laminating a positive electrode plate, a negative electrode plate, and a separator. The positive electrode plate has a positive electrode active material layer formed on a positive electrode base layer which is a current collector foil made of a metal such as aluminum or an aluminum alloy. The negative electrode plate has a negative electrode active material layer formed on a negative electrode base layer which is a current collector foil made of a metal such as copper or a copper alloy. As for the active material used in the positive electrode active material layer and the negative electrode active material layer, any known material can be used as long as it is capable of intercalating and releasing lithium ions. The separator can be a microporous sheet or nonwoven fabric made of resin. In this embodiment, the electrode body is a wound type electrode body formed by winding electrode plates (positive electrode plate and negative electrode plate). The electrode body provided by the energy storage element 100 may be any form of electrode body, such as a laminated (stacked) electrode body formed by laminating a plurality of flat electrode plates, or a bellows type electrode body in which the electrode plates are folded in a bellows shape.

[0040] The current collector is a conductive current collector (positive electrode current collector and negative electrode current collector) that is electrically and mechanically connected to the electrode terminals 140 and the electrode body. The positive electrode current collector is made of aluminum or an aluminum alloy, similar to the positive electrode base layer of the positive electrode plate of the electrode body, and the negative electrode current collector is made of copper or a copper alloy, similar to the negative electrode base layer of the negative electrode plate of the electrode body.

[0041] In this embodiment, multiple energy storage elements 100 are arranged in the Y-axis direction, but the number of energy storage elements 100 arranged is not particularly limited; it may be one, several dozen, or more. The size and shape of the energy storage elements 100 are also not particularly limited; they may be oblong, elliptical, cylindrical, or polygonal prism shapes other than rectangular parallelepipeds. The energy storage elements 100 are not limited to non-aqueous electrolyte secondary batteries; they may be secondary batteries other than non-aqueous electrolyte secondary batteries, or capacitors. The energy storage elements 100 may not be secondary batteries, but primary batteries that allow the user to use the stored electricity without charging. The energy storage elements 100 may be batteries using solid electrolytes. The energy storage elements 100 may be pouch-type energy storage elements.

[0042] The holder 200 is positioned alongside the energy storage element 100 in the Y-axis direction and is a component that insulates and / or heats the energy storage element 100 from other components. The holder 200 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), polyetherether ketone (PEEK), tetrafluoroethylene perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyethersulfone (PES), polyamide (PA), ABS resin, or composite materials thereof, or from heat-insulating materials such as mica. All holders 200 may be made of the same material, or any of the holders 200 may be made of different materials.

[0043] In this embodiment, the holder 200 has walls on both sides of the energy storage element 100 in the X-axis direction, both sides of the Y-axis direction, and both sides of the Z-axis direction, thereby holding the energy storage element 100 and having the function of positioning the energy storage element 100. Specifically, the holder 200 has a holder body portion 210 arranged along the long side surface 111 of the energy storage element 100, an upper wall portion 230 arranged above the energy storage element 100 (in the Z-axis positive direction), and leg portions 220 that contact the bottom wall portion 315 (see Figure 2) of the outer casing 300. The leg portion 220 has a leg bottom surface 220a (see Figures 2 and 3) that contacts the bottom wall portion 315. The upper wall portion 230 and the leg portion 220 are each arranged at both ends of the holder 200 in the X-axis direction. In this embodiment, the legs 220 of the holder 200 ensure an insulating distance between the bottom wall 315 of the metal outer casing body 310 and the energy storage element 100 held by the holder 200.

[0044] Each of the multiple holders 200 included in the energy storage element array 10 is arranged in a continuous line in the Y-axis direction, as shown in Figure 2, with an energy storage element 100 sandwiched between adjacent holders 200. As a result, the multiple upper wall portions 230 and the multiple leg portions 220 are also arranged in the Y-axis direction. In other words, in each of the two energy storage element units 30 arranged in the X-axis direction, rows of upper wall portions 230 extending in the Y-axis direction are formed at the ends in the Z-axis positive direction and at both ends in the X-axis direction. In each of the two energy storage element units 30, rows of leg portions 220 extending in the Y-axis direction are arranged at the ends in the Z-axis negative direction and at both ends in the X-axis direction.

[0045] When focusing on one energy storage element unit 30, of the two rows of upper wall portions 230 that the energy storage element unit 30 has, the row of upper wall portions 230 that is closer to the other energy storage element unit 30 functions as a portion that supports the duct 50a, which is a flow path forming member 50 (see Figure 1). Furthermore, when focusing on one energy storage element unit 30, the row of bottom surfaces 220a of each of the two rows of legs 220 that the energy storage element unit 30 has contacts the bottom wall portion 315 of the outer casing 300. In other words, the row of bottom surfaces 220a of the legs functions as the bottom surface of the energy storage element unit 30.

[0046] In this embodiment, the plurality of holders 200 included in the energy storage element array 10 include holders 200 positioned between two energy storage elements 100 (see Figure 3) and holders 200 positioned at both ends of the energy storage element array 10 in the Y-axis direction (see Figure 2). The former holders 200 are called, for example, inter-cell holders, and the latter holders 200 are called, for example, end holders. These two types of holders 200 have the above-mentioned components in common (holder body portion 210, leg portion 220, and upper wall portion 230).

[0047] The busbar plate 20 is a flat plate-shaped member that positions multiple busbars (not shown) for multiple energy storage elements 100 included in the energy storage element array 10. The busbar plate 20 is made of an insulating material such as PC, PP, PE, or PS, which can be used as the material for the holder 200. The busbar plate 20 has busbar openings 21 (see Figure 1) where the busbars are placed, and for example, one busbar is placed in each of the multiple busbar openings 21. These multiple busbars may be connected in series with all the energy storage elements 100, or any of the energy storage elements 100 may be connected in parallel and then in series, or all the energy storage elements 100 may be connected in parallel.

[0048] The outer casing 300 is a roughly rectangular parallelepiped (box-shaped) container that constitutes the outer casing (outer shell) of the energy storage device 1. The outer casing 300 is positioned outside the two energy storage element units 30, fixing the two energy storage element units 30 in predetermined positions and protecting them from impacts, etc. The outer casing 300 is a metal case formed from a metal component such as aluminum, aluminum alloy, stainless steel, iron, or plated steel sheet. In this embodiment, the outer casing 300 is formed from die-cast aluminum (aluminum die-cast). The outer casing 300 may also be formed from an insulating material such as any resin material that can be used for the holder 200 of the energy storage element unit 30.

[0049] As shown in Figure 1, the exterior body 300 has an exterior body main body 310 that constitutes the main body of the exterior body 300 and a cover 320 that constitutes the cover of the exterior body 300. As shown in Figure 2, the exterior body main body 310 is a housing with two openings 310a formed in the Z-axis positive direction (one side of the third direction) and accommodates two energy storage element units 30. Specifically, the exterior body main body 310 has a pair of side wall portions 312 located at both ends in the X-axis direction, a first end wall portion 313 located at the Y-axis negative end, and a second end wall portion 314 located at the Y-axis positive end. The exterior body main body 310 further has a partition wall portion 316 that separates the two energy storage element units 30 and is located between the two energy storage element units 30. As shown in Figure 2, the partition wall 316 is provided protruding from the bottom wall 315 between the two energy storage element units 30 and is connected to the first end wall 313 and the second end wall 314.

[0050] The cover 320 is a flat, rectangular member that collectively closes the two openings 310a of the outer casing body 310. After the two energy storage element units 30 are housed in the outer casing body 310, the outer casing body 310 and the cover 320 are joined together by bolts, welding, adhesive, or the like. Terminal blocks for external terminals (positive external terminals and negative external terminals) may be attached to the outer casing body 310 or the cover 320, and the external terminals may be arranged on said terminal blocks.

[0051] In the energy storage device 1 configured in this way, a duct 50a, which functions as a flow path forming member 50, is placed between the two energy storage element units 30, and cooling gas is supplied to the two energy storage element units 30 through the duct 50a. Furthermore, a first sealing member 61 (see Figure 1), a second sealing member 62, and a third sealing member 63 are placed inside the outer casing 300, thereby forming a space (a space through which gas flows) for efficiently cooling the two energy storage element units 30. Hereinafter, with reference to Figures 4 to 6 in addition to Figures 1 to 3 described above, the structure (cooling structure) for efficiently cooling the two energy storage element units 30 in the energy storage device 1 according to this embodiment will be explained.

[0052] [2. Cooling structure according to the embodiment] Figure 4 is a bottom view (viewed from the negative Z-axis direction) of the duct 50a according to the embodiment. Figure 5 is a diagram showing the structural relationship between the holder 200 and the energy storage element 100 according to the embodiment. In Figure 5, the holder 200 is simply shown in cross-section in the YZ plane passing through the VV line in Figure 3, and the energy storage elements 100 located on both sides of the holder 200 in the Y-axis direction are shown in side views. Figure 6 is a diagram showing the structural relationship between the duct 50a, the two energy storage element units 30, and the casing 300 according to the embodiment. In Figure 6, the duct 50a and the casing body 310 are simply shown in cross-section in the XZ plane passing through the VI-VI line in Figure 4, and the lid 320 is not shown. In Figure 6, the shape and configuration of the holder 200 and the busbar plate 20 when viewed from the negative Y-axis direction are simply shown. Furthermore, in Figure 6, the gas flow is schematically represented by white arrows.

[0053] In this embodiment, the duct 50a, which functions as a flow path forming member 50, has an inlet 51 for introducing gas into the interior and an opening 52 for releasing gas from the interior toward each of the two energy storage element units 30, as shown in Figures 1, 2, and 4. The inlet 51 is located at the Y-axis negative end of the duct 50a, and the Y-axis positive end of the duct 50a is closed. In other words, the gas that flows into the duct 50a from the inlet 51 flows out of the duct 50a through the opening 52. The cover 320 is provided with a notch 328 as shown in Figure 1, and the inlet 51 of the duct 50a is exposed to the outside through the notch 328. Upstream of the inlet 51, for example, a blower (not shown) is connected to send air from inside the mobile body on which the energy storage device 1 is mounted toward the inlet 51. Gas is supplied to the duct 50a from this blower at predetermined timings or continuously. The air or other gas that flows into the duct 50a from the inlet 51 flows out from the opening 52 and is directed towards each of the two energy storage element units 30. This cools the multiple energy storage elements 100 of the two energy storage element units 30.

[0054] More specifically, as shown in Figure 4, the opening 52 is provided in the lower wall portion 53 of the duct 50a, which is the wall portion in the negative Z-axis direction, and includes a first opening 52a and a second opening 52b. The first opening 52a allows gas to flow out toward one of the two energy storage element units 30. The second opening 52b allows gas to flow out toward the other of the two energy storage element units 30. The first opening 52a and the second opening 52b are spaced apart.

[0055] As described above, the duct 50a according to this embodiment has a first opening 52a and a second opening 52b, which are dedicated to each of the two energy storage element units 30 and are provided independently of each other. Therefore, the gas inside the duct 50a can be efficiently directed to each of the two energy storage element units 30, and as a result, the two energy storage element units 30 can be cooled more efficiently.

[0056] In the energy storage device 1 configured in this way, the duct 50a is positioned between two energy storage element units 30, as shown in Figure 6. More specifically, at least a portion of the duct 50a in the Z-axis direction is inserted between two energy storage element units 30 aligned in the X-axis direction, thereby suppressing an increase in size in the height direction (Z-axis direction).

[0057] As described above, the energy storage device 1 according to this embodiment comprises two energy storage element units 30 arranged side by side in the X-axis direction, and a flow path forming member 50 positioned between the two energy storage element units 30, having a gas flow path 59 (see Figure 6) extending in the Y-axis direction inside. Each of the two energy storage element units 30 has a plurality of energy storage elements 100 arranged side by side in the Y-axis direction. The flow path forming member 50 has an opening 52 that allows gas to flow out from the inside toward each of the two energy storage element units 30.

[0058] In this configuration, a flow path forming member 50 is positioned between two energy storage element units 30 aligned in the X-axis direction in this embodiment, allowing gas (such as cooling air) flowing out from the flow path forming member 50 to be directed onto the two energy storage element units 30. Furthermore, because the flow path forming member 50 is positioned between the two energy storage element units 30, the increase in the height (width in the Z-axis direction) of the energy storage device 1 due to the presence of the flow path forming member 50 is suppressed. Thus, the energy storage device 1 according to this embodiment is an energy storage device 1 that can efficiently cool multiple energy storage elements 100 while suppressing an increase in size.

[0059] More specifically, in this embodiment, as shown in Figure 6, a portion of the duct 50a, which is a flow path forming member 50, in the Z-axis direction is housed in the space between the busbar plates 20 of each of the two energy storage element units 30 that are aligned in the X-axis direction. In other words, the duct 50a is positioned using the lateral space in the X-axis direction of the busbar plates 20, which is necessary for positioning the multiple busbars that are joined to each of the multiple energy storage elements 100. As a result, the increase in size in the height direction (Z-axis direction) is suppressed compared to, for example, when the duct 50a is positioned above or below the two energy storage element units 30 (in the positive or negative Z-axis direction).

[0060] The space between the two energy storage element units 30 aligned in the X-axis direction is, when viewed from the Y-axis direction, the space between the two energy storage element units 30 in the X-axis direction and is included in the overlapping range of the widths of the two energy storage element units 30 in the Z-axis direction (range A in Figure 6 in this embodiment). In other words, by arranging part or all of the flow path forming member 50 in this space, the increase in the size of the energy storage device 1 in the Z-axis direction due to the inclusion of the flow path forming member 50 is suppressed.

[0061] In this embodiment, as shown in Figures 1 and 4, a first sealing member 61 extending in the Y-axis direction is positioned between the duct 50a and each of the two energy storage element units 30.

[0062] In this configuration, the first sealing member 61 prevents the gas supplied from the flow path forming member 50 from leaking out between the flow path forming member 50 and the energy storage element unit 30. Specifically, as shown in Figure 6, the leakage of gas at the upper ends of the two first spaces 321 located between the two energy storage element units 30 aligned in the X-axis direction is prevented by the two first sealing members 61.

[0063] In this embodiment, as the sealing member such as the first sealing member 61, for example, an adhesive tape is used, in which an adhesive is applied to both sides or one side of a tape-shaped base material. As the base material, a foam made of PE or acrylic, a nonwoven fabric, or a film made of PP or PE is used. In this embodiment, the duct 50a is fixed to the inner surface of the lid 320 (see Figure 1) of the outer casing 300 with screws or the like, and is positioned in the position shown in Figure 6 when the lid 320 is joined to the outer casing body 310. At this time, the duct 50a receives a pressing force from the lid 320 in a direction toward the two energy storage element units 30, and this pressing force compresses the first sealing member 61. As a result, relatively high airtightness can be obtained between the duct 50a and each of the two energy storage element units 30. This effect also applies to the second sealing member 62 and the third sealing member 63, which will be described below.

[0064] In this embodiment, each of the two energy storage element units 30 has multiple energy storage elements 100, with the electrode terminals 140 of each energy storage element 100 facing one side of the Z-axis direction (the Z-axis positive direction in this embodiment) which is perpendicular to the Y-axis and X-axis directions. The duct 50a is located at the Z-axis positive end between the two energy storage element units 30.

[0065] In this embodiment, each of the two energy storage element units 30 has multiple energy storage elements 100 in an orientation where the electrode terminals 140 of the multiple energy storage elements 100 face upward. The duct 50a can allow gas to flow out to the multiple energy storage elements 100 from an opening 52 that faces downward. This allows, for example, gas with a relatively high density due to its low temperature to be efficiently applied to the multiple energy storage elements 100. This is advantageous for efficient cooling of the two energy storage element units 30.

[0066] In this embodiment, each of the two energy storage element units 30 has a plurality of holders 200 that hold each of the plurality of energy storage elements 100. The flow path forming member 50 is positioned in contact with the Z-axis positive ends of the plurality of holders 200 of each of the two energy storage element units 30. The holders 200 have one or more grooves 211 that allow gas to pass in the X-axis direction.

[0067] Specifically, as shown in Figure 6, the flow path forming member 50 is supported by the upper wall portion 230 located at the Z-axis positive end of the holder 200. As shown in Figures 3 and 5, the holder 200 has grooves 211 formed to traverse the holder body portion 210 in the X-axis direction. Multiple grooves 211 are arranged in a row in the Z-axis direction on the holder body portion 210. The holder 200 shown in Figure 5 is an inter-cell holder located between two energy storage elements 100, and the holder body portion 210 has grooves 211 on each side in the Y-axis direction. The portion of the holder body portion 210 other than the grooves 211 is configured to contact the energy storage elements 100 as shown in Figure 5, and the grooves 211 form a gap between the holder body portion 210 and the energy storage elements 100 through which gas can pass.

[0068] In this configuration, each end of the duct 50a in the X-axis direction is supported by a plurality of holders 200. This allows the flow path forming member 50 to be stably supported, and the flow path forming member 50 is less susceptible to the heat from the energy storage element 100. Specifically, in this embodiment, as shown in Figures 1, 4, and 6, each end of the duct 50a in the X-axis direction is supported by the upper wall portion 230 of each of the plurality of holders 200 via a first sealing member 61. Furthermore, since the holder 200 has a groove portion 211 that allows gas to pass through in the X-axis direction, as shown in Figure 6, gas supplied from the duct 50a on one side in the X-axis direction can be circulated to the other side in the X-axis direction. This allows the energy storage element 100 held in the holder 200 to be cooled over a wide area in the X-axis direction.

[0069] In this embodiment, as shown in Figures 3 and 5, the holder 200 has one or more ribs 212 inside the groove 211, and the protruding length of the rib 212 (length in the Y-axis direction) is approximately the same as the depth of the groove 211 in the Y-axis direction. Therefore, the tip of the rib 212 can contact the long side surface 111 of the energy storage element 100 facing the rib 212. This suppresses the reduction in the effect of suppressing swelling of the energy storage element 100, which would occur if, for example, the holder 200 had a portion (groove 211) that did not contact the long side surface 111 of the energy storage element 100. Furthermore, when the energy storage element 100 swells in the Y-axis direction, the rib 212 prevents the groove 211 from narrowing in the Y-axis direction. This ensures a more reliable flow path 59 for the gas in the groove 211 for cooling the energy storage element 100.

[0070] There is no particular limit to the number of grooves 211 in the holder 200. For example, increasing the number of grooves 211 arranged in the Z-axis direction in the holder 200, that is, narrowing the width of one groove 211 in the Z-axis direction, can improve the rigidity of the holder 200. As a result, the effect of suppressing swelling of the energy storage element 100 is enhanced. Decreasing the number of grooves 211 arranged in the Z-axis direction in the holder 200, that is, widening the width of one groove 211 in the Z-axis direction, can reduce the flow resistance for gas flowing along the grooves 211.

[0071] In this embodiment, multiple ribs 212 are dispersed along the direction of gas flow within the groove 211. As a result, turbulence is easily generated in the gas flow within the groove 211, thereby improving the cooling function.

[0072] In this embodiment, the two energy storage element units 30 are arranged in the bottom wall portion 315 of the outer casing 300 that houses the two energy storage element units 30 and the duct 50a, as shown in Figures 2 and 6. A second sealing member 62 is positioned between the bottom wall portion 315 and the end of the bottom surface of each of the two energy storage element units 30 that is closer to the other energy storage element unit 30, in the X-axis direction.

[0073] Specifically, the energy storage element unit 30 is positioned on the bottom wall 315 with the bottom surface 220a of each of the legs 220 of the multiple holders 200 in contact with the bottom wall 315. In other words, the bottom surface of the energy storage element unit 30 is formed by rows of leg bottom surfaces 220a extending in the Y-axis direction. One energy storage element unit 30 has two rows of leg bottom surfaces 220a extending in the Y-axis direction, and as shown in Figures 2 and 6, a second sealing member 62 is positioned between the other row of leg bottom surfaces 220a that is closer to the energy storage element unit 30 and the bottom wall 315.

[0074] This configuration improves the airtightness of the space between the two energy storage element units 30 and between the duct 50a and the bottom wall portion 315 of the outer casing 300. In other words, gas leakage at the lower end of the first space 321 shown in Figure 6 is suppressed by the second sealing member 62. As a result, the gas supplied to each of the two first spaces 321 can be efficiently delivered towards the energy storage element unit 30 facing the first space 321.

[0075] Furthermore, in this embodiment, a third sealing member 63 is positioned between the bottom wall portion 315 and the end of the bottom surface of each of the two energy storage element units 30 that is furthest from the other energy storage element unit 30 in the X-axis direction. Specifically, as shown in Figures 2 and 6, the third sealing member 63 is positioned between the bottom wall portion 315 and the end of the row of two leg bottom surfaces 220a of one energy storage element unit 30 that is furthest from the other energy storage element unit 30.

[0076] This configuration improves the airtightness of the space outside the two energy storage element units 30. Specifically, as shown in Figure 6, a second space 322 through which gas can flow is formed on the side of each of the two energy storage element units 30 opposite to the other energy storage element unit 30. Gas leakage at the lower end of this second space 322 is suppressed by the third sealing member 63. This allows, for example, the gas that has exchanged heat with the energy storage element unit 30 to be efficiently guided to a predetermined outlet (discharge port). In other words, the occurrence of a state in which the gas that has exchanged heat with the energy storage element unit 30 remains stagnant is suppressed. There are no particular limitations on the position and shape of the outlet (discharge port) for the gas that has reached the second space 322 after heat exchange. The discharge port may be provided, for example, on the second end wall portion 314, the side wall portion 312, or the bottom wall portion 315 of the outer casing body 310, or on the lid 320. The discharge port may be formed by a gap created by not sealing the space between the outer casing body 310 and the lid 320.

[0077] The above description of the energy storage device 1 according to the embodiment focuses on the flow path forming member 50 (duct 50a) and related configurations. However, the flow path forming member 50 and related configurations may differ from those shown in Figures 1 to 6. Therefore, the following describes variations of the flow path forming member 50 and related configurations, focusing on the differences from the above embodiment.

[0078] [3. Modified Examples of Embodiments] Figure 7 is a perspective view showing a modified embodiment of the energy storage element unit 30 and the outer casing body 410. Figure 8 is a perspective view of the modified embodiment of the outer casing body 410 viewed from diagonally below. Figure 9 is a diagram showing the structural relationship between two modified embodiments of the energy storage element unit 30 and the outer casing body 400. In Figure 9, a simplified cross-section of the outer casing body 410 in the XZ plane passing through the line IX-IX in Figure 7 is shown. The outer casing body 400 in this modified embodiment has a cover that closes both openings 410a (see Figure 7) of the outer casing body 410 at once, but the cover is not shown in Figures 7 to 9. In Figure 9, the shape and configuration of the holder 200 and the busbar plate 20 when viewed from the Y-axis minus direction are simplified, and the gas flow is schematically represented by white arrows.

[0079] The modified energy storage device 1a comprises two energy storage element units 30 arranged side by side in the X-axis direction perpendicular to the Y-axis direction, and a flow path forming member 50 positioned between the two energy storage element units 30, having a gas flow path 59 extending in the Y-axis direction inside. Each of the two energy storage element units 30 has a plurality of energy storage elements 100 arranged side by side in the Y-axis direction. The flow path forming member 50 has an opening 421 that allows gas to flow out from the inside toward each of the two energy storage element units 30. The outer casing body 410 has a pair of side wall portions 412 positioned at both ends in the X-axis direction, a first end wall portion 413 positioned at the Y-axis negative end, and a second end wall portion 414 positioned at the Y-axis positive end. The outer casing body 410 further has a partition wall portion 416 positioned between the two energy storage element units 30 that separates the two energy storage element units 30. These configurations are common to the energy storage device 1 according to the above embodiment. The energy storage device 1a according to this modified example differs from the energy storage device 1 according to the above embodiment in that the partition wall portion 416 of the outer casing 400 functions as a flow path forming member 50.

[0080] Specifically, in this modified example, the flow path forming member 50 is a partition wall portion 416 that separates the two energy storage element units 30 and is positioned between the two energy storage element units 30, and is formed by a part of the outer casing 400 that houses the two energy storage element units 30. The opening 421 includes a first opening 421a and a second opening 421b, as shown in Figures 7 and 9. The first opening 421a is formed in the first inner wall portion 417 of the partition wall portion 416 that faces one of the two energy storage element units 30. The second opening 421b is formed in the second inner wall portion 418 of the partition wall portion 416 that faces the other of the two energy storage element units 30.

[0081] This configuration allows gas to flow out from the partition wall 416 separating the two energy storage element units 30 toward the energy storage element units 30 on both sides in the thickness direction (X-axis direction). Therefore, a space-efficient energy storage device 1a can be realized. In other words, because the partition wall 416 functions as a flow path forming member 50, there is no need to provide space inside the outer casing 400 to accommodate a separate member such as a pipe or tube for supplying cooling gas to the two energy storage element units 30. Furthermore, since the partition wall 416, which is the flow path forming member 50, is positioned within the width range of the energy storage element units 30 in the Z-axis direction, the increase in the height direction (Z-axis direction) of the energy storage device 1a due to the inclusion of the flow path forming member 50 is more reliably suppressed.

[0082] In this modified example, the partition wall portion 416 is provided projecting between the two energy storage element units 30 from the bottom wall portion 415 where the two energy storage element units 30 are arranged. As shown in Figures 8 and 9, the bottom wall portion 415 has a bottom wall opening 416b that communicates with the interior of the partition wall portion 416 on the surface opposite to the projection direction of the partition wall portion 416 (in the negative Z-axis direction).

[0083] In this configuration, the partition wall portion 416 is a part of the bottom wall portion 415 and is formed as a curved portion that protrudes toward the interior of the outer casing 400. Therefore, the partition wall portion can be manufactured by methods such as casting, press working, or cutting from the back surface of the bottom wall portion 415. In other words, for example, it is unnecessary to perform processing such as forming a long hole in the Y-axis direction in the solid partition wall portion 416, which is elongated in the Y-axis direction. Therefore, an outer casing 400 equipped with a partition wall portion 416 having a gas flow path 59 extending in the Y-axis direction can be manufactured relatively easily. When the partition wall portion 416 is formed in this way, an opening (bottom wall opening 416b) is provided on the back surface of the bottom wall portion 415 that communicates with the interior of the partition wall portion 416 (gas flow path 59). However, this bottom wall opening 416b can be blocked, for example, by the installation surface on which the energy storage device 1a is installed. Therefore, leakage of gas from inside the partition wall 416 through the bottom wall opening 416b is suppressed. This is advantageous for efficient cooling of the two energy storage element units 30.

[0084] In this modified example, the outer casing 400 has a gas inlet 416a formed in the first end wall portion 413 on one side in the Y-axis direction (Y-axis negative direction) that connects the outside of the outer casing 400 to the inside of the partition wall portion 416. The outer casing 400 further has a gas outlet 419 formed in the second end wall portion 414 on the other side in the Y-axis direction (Y-axis positive direction) that connects the space outside the partition wall portion 416 and inside the outer casing 400 to the outside of the outer casing 400.

[0085] In this configuration, the gas supplied from one side in the Y-axis direction to the partition wall 416, which functions as a flow path forming member 50, exchanges heat with the two energy storage element units 30 and is then discharged to the outside of the outer casing 400 through an outlet 419 provided on the other side in the Y-axis direction. This allows the gas for cooling the two energy storage element units 30 to circulate more smoothly. As a result, for example, the amount of cooling gas supplied to the two energy storage element units 30 per unit time can be increased.

[0086] More specifically, in this modified example, the discharge ports 419 are formed at both ends of the second end wall portion 414 in the X-axis direction. With this configuration, the gas that flows into the interior of the partition wall portion 416 from the inlet 416a of the first end wall portion 413 and cools the two energy storage element units 30 by flowing on both sides in the X-axis direction is discharged to the outside of the outer casing 400 from the discharge ports 419 provided at both ends of the second end wall portion 414 in the X-axis direction. Therefore, the gas that has finished heat exchange can be quickly discharged to the outside of the outer casing 400.

[0087] In this modified example, similar to the above embodiment, the second sealing member 62 and the third sealing member 63 are positioned between the bottom surfaces of each of the two energy storage element units 30 and the bottom wall portion 415 of the outer casing 400 (see Figure 9). Furthermore, as described above, the holder 200 is provided with one or more groove portions 211 through which gas passes in the X-axis direction. As a result, the gas flowing out from the opening 421 of the partition wall portion 416 can efficiently flow into the groove portions 211 and exchange heat with the energy storage element 100. Furthermore, the gas after heat exchange is efficiently discharged to the outside of the outer casing 400 via the discharge port 419 from the second space 422 (see Figure 9) located outside each of the two energy storage element units 30.

[0088] In this modified example, as shown in Figure 7, the first inner wall portion 417 of the partition wall portion 416 is provided with a plurality of first openings 421a arranged in the Y-axis direction. Each of these plurality of first openings 421a is positioned, for example, opposite the groove portion 211 of the holder 200 in the X-axis direction. Therefore, gas flowing out from one first opening 421a can efficiently flow into the groove portion 211 opposite the first opening 421a in the X-axis direction. Although not shown in Figure 7, the second inner wall portion 418 of the partition wall portion 416 also has a plurality of second openings 421b arranged in the Y-axis direction.

[0089] It is not essential that the multiple first openings 421a and multiple second openings 421b of the opening 421, which are aligned in the Y-axis direction, be provided in the same number corresponding to multiple holders 200. The first openings 421a and / or second openings 421b may each be configured as a single opening that spans multiple holders 200. Alternatively, multiple first openings 421a and / or second openings 421b may be provided so as to span multiple holders 200, and configured for each block of the energy storage element unit 30. Specifically, one first opening 421a and one second opening 421b may be provided corresponding to the block in the Y-axis positive direction and the block in the Y-axis negative direction, respectively, in the energy storage element unit 30.

[0090] The size and shape of the first opening 421a and the second opening 421b are not particularly limited. For example, the opening area may be different for the first opening 421a (second opening 421b) in the positive Y-axis direction and the first opening 421a (second opening 421b) in the negative Y-axis direction, taking into consideration cooling efficiency depending on the position in the Y-axis direction. The first opening 421a and the second opening 421b do not need to be rectangular in the ZY plane. The shape of the first opening 421a and the second opening 421b can be changed to a trapezoid or rhombus, for example, depending on the position of the energy storage element unit 30 in the Z-axis direction or the degree to which heat accumulates. When the opening 421 has multiple first openings 421a, all first openings 421a do not need to be the same shape, and a free combination is possible. The same applies to the second opening 421b.

[0091] Furthermore, although it has been explained that the multiple first openings 421a and multiple second openings 421b are located at corresponding positions in the Y-axis direction, i.e., at the same positions when viewed from the X-axis direction, this is not essential. The multiple first openings 421a and multiple second openings 421b may be arranged in a staggered pattern at different positions in the Y-axis direction. In this case, the positions of the holders 200 of the energy storage element units 30 in the positive and negative X-axis directions may also be provided at positions corresponding to the first openings 421a and second openings 421b, respectively.

[0092] The two outlets 419 have been described as being located at the ends of the outer casing 400 in the positive Y-axis direction. However, the outlets 419 may also be provided at both ends of the outer casing 400 in the positive Y-axis direction and the negative Y-axis direction, or they may be located only at the end in the positive Y-axis direction for one energy storage element unit 30 and only at the end in the negative Y-axis direction for the other energy storage element unit 30. Furthermore, the outlets 419 may be formed in the bottom wall portion 415 or the lid 320.

[0093] [4. Regarding other variations] Although embodiments and modified versions thereof of the present invention have been described above, the present invention is not limited to the embodiments and modified versions described herein. The embodiments and modified versions disclosed herein are illustrative in all respects, and the scope of the present invention includes all modifications in the sense and scope equivalent to the claims.

[0094] In the above embodiment, the opening 52 of the duct 50a included a first opening 52a and a second opening 52b that were spaced apart in the X-axis direction, but this is not essential. For example, a single through-hole provided in the lower wall portion 53 of the duct 50a may be used as the opening 52. Even in this case, if the opening 52 is positioned so as to straddle the partition wall portion 316 in the X-axis direction when viewed from the Z-axis direction, the gas flowing out from the opening 52 will be dispersed to both sides in the X-axis direction by the partition wall portion 316. As a result, each of the two energy storage element units 30 can be cooled by the gas.

[0095] In the above embodiment, the outer casing body 310 has sufficient height in the Z-axis direction to house the energy storage element unit 30, and is configured so that the energy storage element unit 30 is not exposed when viewed from the XY plane, but this is not essential. The outer casing body 310 may have a height of about two-thirds or half of the energy storage element unit 30 in the Z-axis direction to house a part of the energy storage element unit 30 in the Z-minus direction, and leave the remaining part of the energy storage element unit 30 (a part of the energy storage element unit 30 in the Z-plus direction) exposed. In this case, the lid 320 may have a height of about one-third or half of the energy storage element unit 30 in the Z-axis direction to house the part of the energy storage element unit 30 in the Z-plus direction.

[0096] The first opening 52a and the second opening 52b do not necessarily have to be elongated openings (slits) in the Y-axis direction, as shown in Figure 4. The first opening 52a and the second opening 52b may each be formed, for example, by a plurality of through holes distributed in the Y-axis direction.

[0097] The holder 200 does not necessarily have to have one or more grooves 211. Even if the holder body 210 of the holder 200 is a flat plate parallel to the XZ plane, for example, by having one or more protrusions (projections) on the surface of the holder body 210 facing the energy storage element 100, a gap through which gas can pass can be forcibly formed between the holder body 210 and the long side surface 111 (see Figure 2) of the energy storage element 100. This makes it possible to efficiently cool the energy storage element 100 with gas flowing out from the flow path forming member 50.

[0098] The holder 200 does not necessarily have legs 220. For example, if the outer casing 300 is made of resin, it is not necessary to ensure an insulating distance between the bottom wall 315 of the outer casing 300 and the energy storage element 100. In this case, the wall portion of the holder 200 that supports the bottom surface 113 of the energy storage element 100 may be in contact with the bottom wall 315. Even if the outer casing 300 is made of metal, if an insulating member such as a resin sheet is placed between the energy storage element unit 30 and the bottom wall 315, the holder 200 does not necessarily have legs 220 for the same reason.

[0099] The inlet 51 (see Figure 2) of the duct 50a, which is the flow path forming member 50, is located at the end of the duct 50a in the negative Y-axis direction and opens in the negative Y-axis direction, but the orientation of the inlet 51 is not limited to this. For example, the inlet 51 of the duct 50a may open upward (in the positive Z-axis direction). In this case, by providing a through hole in the upper surface of the cover 320, cooling gas can be supplied to the inlet 51 through the through hole.

[0100] The first sealing member 61 does not need to be an adhesive tape. For example, it may be a long member in the Y-axis direction formed of resin or rubber without an adhesive layer. Even in this case, it is possible to fix the first sealing member 61 by sandwiching it between the duct 50a and the energy storage element unit 30. The first sealing member 61 may be formed only of an adhesive layer or bonding layer without a base layer. For example, the duct 50a can be fixed to the energy storage element unit 30 by applying adhesive to the Z-axis negative surface of the duct 50a and / or the upper wall portion 230 of the energy storage element unit 30. This also improves the airtightness between the duct 50a and the energy storage element unit 30. These supplementary notes regarding the types of the first sealing member 61 also apply to the second sealing member 62 and the third sealing member 63. Furthermore, the first sealing member 61, the second sealing member 62 and the third sealing member 63 may be sponge-like (porous) members with adhesive layers on one or both sides. Specifically, the first sealing member 61 is bonded to the flow path forming member 50 by providing an adhesive layer on the flow path forming member 50 side, while the side facing the energy storage element unit 30 may have no adhesive layer and its sponge-like surface may be exposed. Similarly, the second sealing member 62 and the third sealing member 63 are bonded to the outer casing body 310 by providing an adhesive layer on the outer casing body 310 side, while the side facing the energy storage element unit 30 may have no adhesive layer and its sponge-like surface may be exposed.

[0101] The energy storage device 1 does not need to have at least one or all of the first sealing member 61, the second sealing member 62, and the third sealing member 63. For example, if the amount of gas supplied to the flow path forming member 50 per unit time is relatively large, it is possible to cool each of the multiple energy storage elements 100 to a degree that suppresses performance degradation, even if these sealing members are not provided.

[0102] The cooling gas supplied from the flow path forming member 50 to the two energy storage element units 30 does not have to be air; for example, it may be carbon dioxide. The type of cooling gas may be appropriately determined depending on the equipment in which the energy storage device 1 or 1a is located, the surrounding environment, or operating costs.

[0103] The present invention also includes forms constructed by arbitrarily combining the components of the above embodiments and their variations. [Industrial applicability]

[0104] This invention can be applied to energy storage devices equipped with energy storage elements such as lithium-ion secondary batteries. [Explanation of Symbols]

[0105] 1. 1a Energy storage device 10 Energy storage element array 20 Busbar Plates 30 Energy Storage Element Units 50 Flow channel forming member 50a duct 51, 416a Inlet 52,421 openings 52a, 421a First opening 52b, 421b Second opening 53 Lower wall part 59 Flow channels 61 First sealing member 62 Second sealing member 63 Third sealing member 100 energy storage elements 140 Electrode terminal 200 holder 210 Holder body 211 Groove 212 Rib 220 Legs 220a Bottom surface of the leg 230 Upper wall section 300, 400 Exterior 310, 410 Main body of the exterior 313, 413 First end wall part 314, 414 Second end wall portion 315, 415 bottom wall 316, 416 Shi cut wall part 416b Bottom wall opening 417 First Inner Wall Section 418 Second Inner Wall Section 419 Discharge Outlet

Claims

1. Each of two energy storage element units has multiple energy storage elements arranged in a line in a first direction, and the other of two energy storage element units has multiple energy storage elements arranged in a line in a second direction perpendicular to the first direction, The system comprises a flow path forming member having a gas flow path extending in the first direction, which is positioned between the two energy storage element units, The flow channel forming member has an opening that allows the gas to flow out from the inside toward each of the two energy storage element units. Each of the two energy storage element units has the plurality of energy storage elements such that the electrode terminals of the plurality of energy storage elements are oriented toward one side of a third direction perpendicular to the first direction and the second direction. The flow path forming member is positioned at one end in the third direction between the two energy storage element units. Energy storage device.

2. A first sealing member extending in the first direction is positioned between the flow path forming member and each of the two energy storage element units. The energy storage device according to claim 1.

3. Each of the two energy storage element units has a plurality of holders for holding each of the plurality of energy storage elements, The flow path forming member is positioned in contact with one end of the plurality of holders in the third direction of each of the two energy storage element units, The holder has one or more grooves that allow the gas to pass through in the second direction. The energy storage device according to claim 1.

4. Two energy storage element units, each having a plurality of energy storage elements arranged in a first direction, wherein the two energy storage element units are arranged in a second direction perpendicular to the first direction, The system comprises a flow path forming member having a gas flow path extending in the first direction, which is positioned between the two energy storage element units, The flow channel forming member has an opening that allows the gas to flow out from the inside toward each of the two energy storage element units. A first sealing member extending in the first direction is positioned between the flow path forming member and each of the two energy storage element units. The two energy storage element units are arranged on the bottom wall portion of the outer casing that houses the two energy storage element units and the flow path forming member. A second sealing member is positioned between the bottom wall portion and the end of the bottom surface of each of the two energy storage element units that is closer to the other energy storage element unit, in the second direction. Energy storage device.

5. A third sealing member is disposed between the bottom wall portion and the end of the bottom surface of each of the two energy storage element units that is furthest from the other energy storage element unit in the second direction. The energy storage device according to claim 4.

6. Two energy storage element units, each having a plurality of energy storage elements arranged in a first direction, wherein the two energy storage element units are arranged in a second direction perpendicular to the first direction, The system comprises a flow path forming member having a gas flow path extending in the first direction, which is positioned between the two energy storage element units, The flow channel forming member has an opening that allows the gas to flow out from the inside toward each of the two energy storage element units. The flow path forming member is a partition wall portion that separates the two energy storage element units and is positioned between the two energy storage element units, and is a partition wall portion formed by a part of the outer casing that houses the two energy storage element units. The aforementioned opening is A first opening is formed in the first inner wall portion of the partition wall portion, which faces one of the two energy storage element units, The partition wall includes a second opening formed in the second inner wall portion facing the other of the two energy storage element units, Energy storage device.

7. The partition wall portion is provided protruding from the bottom wall portion where the two energy storage element units are arranged, between the two energy storage element units. The bottom wall portion has a bottom wall opening on the side opposite to the protruding direction of the partition wall portion, which communicates with the interior of the partition wall portion. The energy storage device according to claim 6.

8. The aforementioned exterior body further, A gas inlet is formed in the first end wall on one side of the first direction, connecting the outside of the exterior body and the inside of the partition wall, The second end wall on the other side of the first direction has a gas outlet that connects the space outside the partition wall and inside the exterior body to the outside of the exterior body, The energy storage device according to claim 6 or 7.

9. Each of two energy storage element units has multiple energy storage elements arranged in a line in a first direction, and the other of two energy storage element units has multiple energy storage elements arranged in a line in a second direction perpendicular to the first direction, The system comprises a flow path forming member having a gas flow path extending in the first direction, which is positioned between the two energy storage element units, The flow channel forming member has an opening that allows the gas to flow out from the inside toward each of the two energy storage element units. The two energy storage element units are arranged on the bottom wall portion of the outer casing that houses the two energy storage element units and the flow path forming member. A second sealing member is positioned between the bottom wall portion and the end of the bottom surface of each of the two energy storage element units that is closer to the other energy storage element unit, in the second direction. Energy storage device.

10. Each of two energy storage element units has multiple energy storage elements arranged in a line in a first direction, and the other of two energy storage element units has multiple energy storage elements arranged in a line in a second direction perpendicular to the first direction, The system comprises a flow path forming member having a gas flow path extending in the first direction, which is positioned between the two energy storage element units, The flow channel forming member has an opening that allows the gas to flow out from the inside toward each of the two energy storage element units. Each of the two energy storage element units has the plurality of energy storage elements such that the electrode terminals of the plurality of energy storage elements are oriented toward one side of a third direction perpendicular to the first direction and the second direction. Each of the two energy storage element units comprises a flat busbar plate with its thickness direction oriented in the third direction, and a busbar plate that holds a plurality of busbars connected to a plurality of electrode terminals, The flow path forming member is positioned between the two busbar plates. Energy storage device.

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