Power storage device

Abstract

This power storage device comprises a first tray and a second tray arranged in a first direction, and a power storage element disposed between the first tray and the second tray. The first tray includes a first tray body positioned opposite the power storage element in the first direction, a first protruding portion protruding toward one side in the first direction from the first tray body, and a first insertion portion formed by a cavity inside the first protruding portion and opening toward the other side in the first direction. The second tray includes a second tray body positioned opposite the power storage element in the first direction, and a second protruding portion protruding toward the one side in the first direction. The second protruding portion is inserted in the first insertion portion.

Description

Power storage device

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

[0002] Patent Document 1 discloses a battery device. The battery device includes a plurality of batteries provided adjacent to each other. Each battery has a case having a frame-shaped peripheral wall with both ends open and a side wall provided at one end of the peripheral wall, and a battery cell housed in the case and exposed on the other end side of the peripheral wall. In this battery device, in two adjacent batteries, a first fitting portion of one battery and a second fitting portion of the other battery are fitted to each other along the extending direction of the side wall.

[0003] Japanese Unexamined Patent Application Publication No. 2009-231143

[0004] The battery included in the above conventional battery device has a first fitting portion formed at one end side of the peripheral wall and a second fitting portion formed at the other end of the peripheral wall. That is, in the structure in which two adjacent batteries are connected, the case that houses the battery cell needs to have the first fitting portion and the second fitting portion at different positions from each other. Therefore, the configuration of the case tends to be complicated.

[0005] The present invention has been newly made by the inventor of the present application paying attention to the above problems, and an object thereof is to provide a power storage device with a simple configuration and improved reliability.

[0006] A power storage device according to an aspect of the present invention includes a first tray and a second tray arranged in a first direction, and a power storage element disposed between the first tray and the second tray. The first tray includes a first tray body facing the power storage element in the first direction, a first protruding portion protruding to one side of the first direction from the first tray body, and a first insertion portion formed by a cavity inside the first protruding portion and opening to the other side of the first direction. The second tray includes a second tray body facing the power storage element in the first direction, and a second protruding portion protruding to the one side of the first direction. The second protruding portion is inserted into the first insertion portion.

[0007] According to the present invention, a power storage device with a simple configuration and improved reliability can be provided.

[0008] Figure 1 is a perspective view showing the external appearance of an energy storage device according to an embodiment. Figure 2A is a perspective view showing the external appearance of an energy storage unit and a restraining member according to an embodiment. Figure 2B is an exploded perspective view showing a part of the energy storage device according to an embodiment. Figure 3A is a first perspective view showing the configuration of a tray according to an embodiment. Figure 3B is a second perspective view showing the configuration of a tray according to an embodiment. Figure 3C is a perspective view showing the configuration of a tray at the end of an energy storage unit according to an embodiment. Figure 4 is an exploded perspective view showing a part of an energy storage unit according to an embodiment. Figure 5 is a front view showing the positional relationship between a tray and an energy storage element according to an embodiment. Figure 6 is a rear view showing the positional relationship between a tray and an energy storage element according to an embodiment. Figure 7 is a first cross-sectional view of two trays and eight energy storage elements housed in the two trays according to an embodiment. Figure 8 is a second cross-sectional view of two trays and eight energy storage elements housed in the two trays according to an embodiment.

[0009] (1) An energy storage device according to one aspect of the present invention comprises a first tray and a second tray arranged in a first direction, and an energy storage element disposed between the first tray and the second tray, wherein the first tray comprises a first tray body facing the energy storage element in the first direction, a first protrusion that protrudes from the first tray body to one side in the first direction, and a first insertion portion formed by a cavity inside the first protrusion and opening to the other side in the first direction, and the second tray comprises a second tray body facing the energy storage element in the first direction, and a second protrusion that protrudes to the one side in the first direction, the second protrusion being inserted into the first insertion portion.

[0010] According to one aspect of the present invention, the second protrusion of the second tray is inserted into the first insertion portion of the first tray, thereby suppressing displacement of the first tray and the second tray relative to one of them (movement in a direction intersecting the first direction). Since the first insertion portion is formed using the internal space (cavity) of the first protrusion, the configuration of the first tray is simplified compared to the case where the first protrusion and the first insertion portion are arranged in different positions. Therefore, the energy storage device according to this aspect is an energy storage device with improved reliability and a simple configuration.

[0011] (2) In the energy storage device described in (1) above, the first protrusion and the first insertion portion may have a tapered shape in which the width in the direction intersecting the first direction decreases as they advance toward one side of the first direction, and the second protrusion may have the tapered shape corresponding to the first insertion portion.

[0012] According to the energy storage device described in (2) above, the second protrusion is easily inserted into the first insertion part, and the movement of the second protrusion in the direction of exiting the first insertion part is easily permitted. In other words, when the energy storage element expands, the movement of the second tray away from the first tray is easily permitted. This suppresses excessive pressure on the energy storage element between the first tray and the second tray.

[0013] (3) In the energy storage device described in (1) or (2) above, the tip of the second protrusion may be located on one side of the first direction relative to the first tray body.

[0014] According to the energy storage device described in (3) above, the length of the second protrusion of the second tray that is inserted into the first insertion part is relatively long. Therefore, even if the second protrusion moves relatively large in the direction of being withdrawn from the first insertion part, at least a part of the second protrusion remains inserted into the first insertion part. In other words, displacement of the first tray and the second tray relative to one of them (movement in a direction intersecting the first direction) is suppressed.

[0015] (4) In the energy storage device described in any one of (1) to (3) above, the energy storage element may include a container for housing an electrode body, and when viewed from the first direction, the first protrusion, the first insertion portion, and the second protrusion may extend along the outer edge of the container.

[0016] According to the energy storage device described in (4) above, the first insertion portion and the second protrusion portion extend along the outer edge of the energy storage element, so that the connection portion between the first insertion portion and the second protrusion portion is formed along the outer edge of the energy storage element. Therefore, the displacement of one of the first tray and the second tray relative to the other (movement in a direction intersecting the first direction) is suppressed more stably.

[0017] (5) In the energy storage device described in (4) above, when viewed from the first direction, the outer edge of the container is rectangular, and when viewed from the first direction, the first projection, the first insertion portion, and the second projection extend along at least three of the four sides forming the outer edge.

[0018] According to the energy storage device described in (5) above, the connection portion between the second protrusion and the first insertion portion is provided over a wide area along the outer edge of the container of the energy storage element, and the connection portion includes portions along sides that extend in different directions from each other. As a result, the displacement of the first tray relative to one of the second trays (movement in a direction intersecting the Y-axis direction) is suppressed more stably.

[0019] (6) In the energy storage device described in any one of (1) to (5) above, the first protrusion may be a first projection that protrudes in a direction intersecting the first direction and extends in the first direction, the first insertion portion may be a first recess formed inside the first projection and extending in the first direction, the second protrusion may be a second projection that extends in the first direction and the second projection is inserted into the first recess.

[0020] According to the energy storage device described in (6) above, the second protrusion of the second projection is inserted into the first recess of the first insertion part, thereby restricting the movement of the first tray relative to the second tray in the direction in which the second projection extends (first direction) and in the direction intersecting the projection direction of the second projection. Therefore, the displacement of the first tray relative to the second tray is stably suppressed.

[0021] (7) The energy storage device described in any one of (1) to (6) above further comprises a pair of end members that sandwich the first tray, the second tray, and the energy storage unit including the energy storage element in the first direction, and a flexible wire connecting the pair of end members.

[0022] According to the energy storage device described in (7) above, the pair of end members can compress one and the other end faces of the energy storage unit in the first direction. Therefore, the energy storage elements can be compressed more uniformly in the plane intersecting the first direction. Since the wire is flexible, it can restrain the energy storage unit in the first direction while easily allowing the energy storage elements to bulge. Accordingly, excessive compression of the energy storage elements by the pair of end members in the first direction is suppressed.

[0023] (8) In the energy storage device described in (7) above, the first tray may be provided with a first guide portion having a first guide hole through which the wire passes, and the second tray may be provided with a second guide portion having a second guide hole through which the wire passes.

[0024] According to the energy storage device described in (8) above, the wire more reliably prevents one of the first tray and the second tray from shifting in a direction intersecting the first direction relative to the other of the first tray and the second tray.

[0025] Hereinafter, an energy storage device according to an embodiment of the present invention (including its modifications) will be described 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. In each figure, dimensions, etc., are not strictly illustrated. In each figure, the same or similar components are denoted by the same reference numeral.

[0026] In the following description and drawings, the direction in which a pair of terminals in one energy storage element or the direction in which two energy storage units are aligned is defined as the X-axis direction. The direction in which multiple energy storage elements are aligned, the direction in which multiple trays are aligned, or the thickness direction of an energy storage element is defined as the Y-axis direction. The direction in which the container and terminals in an energy storage element are aligned, or the vertical direction is defined as the Z-axis direction. These X-axis, Y-axis, and Z-axis directions intersect each other (orthogonal in this embodiment). Depending on the usage, the Z-axis direction may not be the vertical direction, but for the sake of explanation, the Z-axis direction will be described as the vertical direction below.

[0027] 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. The same applies to the Y-axis and Z-axis directions. Expressions indicating relative directions or orientations, such as parallel and orthogonal, include cases where they are not strictly those directions or orientations. Two directions being parallel means not only that the two directions are perfectly parallel, but also that they are substantially parallel, i.e., that they may have a difference of a few percent. In the following explanation, when "insulation" is used, it means "electrical insulation." Insulating materials have a volume resistivity of 1 × 10⁻⁶. ６ Ωm or greater, more preferably 1 × 10⁻⁶ ７ Ωm or greater, preferably 1 × 10⁻⁶ １０ It is preferable that the material be formed from a material with a density of Ωm or greater.

[0028] (Embodiment) [1. General Description of Energy Storage Device 1] First, the configuration outline of the energy storage device 1 in this embodiment will be described. Figure 1 is a perspective view showing the external appearance of the energy storage device 1 according to this embodiment. Figure 2A is a perspective view showing the external appearance of the energy storage unit 50 and the restraining member 200 according to this embodiment. Figure 2B is an exploded perspective view showing a part of the energy storage device 1 according to this embodiment disassembled. Specifically, Figure 2B shows the restraining member 200 that restrains the energy storage unit 50 in a disassembled state. In Figure 2B, a part of the end member 210A is omitted from the illustration. Inside the outer casing 10, in addition to the members shown in Figures 1, 2A and 2B, a plurality of conductive members connected to a plurality of energy storage elements 60 are housed, and a control device for controlling the charging and discharging of the plurality of energy storage elements 60 may be arranged. However, the illustration and description of these members and devices are omitted.

[0029] 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 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, automated guided vehicles (AGVs), aircraft, 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.

[0030] As shown in Figures 1, 2A, and 2B, the energy storage device 1 comprises an energy storage unit 50 having energy storage elements 60, and a restraining member 200 that restrains the energy storage unit 50. More specifically, the energy storage unit 50 comprises a plurality of energy storage elements 60 and a plurality of trays 100. The plurality of energy storage elements 60 and the plurality of trays 100 are arranged in the Y-axis direction. The Y-axis direction is an example of a first direction. Each of the plurality of trays 100 houses one or more energy storage elements 60. There is no particular limit to the number of energy storage elements 60 housed in one tray 100, but in this embodiment, each of the seven trays 100 houses four energy storage elements 60. In other words, the energy storage unit 50 comprises 28 energy storage elements 60.

[0031] There are no particular limitations on the number of energy storage elements 60 that the energy storage unit 50 has. The energy storage unit 50 only needs to include at least one energy storage element 60 and two trays 100 that are arranged to sandwich the at least one energy storage element 60 in the Y-axis direction. The trays 100 may also be referred to as "spacers" or "cell holders," etc.

[0032] The energy storage element 60 is a secondary battery (single cell) capable of charging and discharging electricity, and more specifically, a non-aqueous electrolyte secondary battery such as a lithium-ion secondary battery. In this embodiment, the energy storage element 60 is a pouch-type energy storage element with a flat shape. The configuration of the energy storage element 60 will be described later with reference to Figure 4, etc.

[0033] The energy storage element 60 is not limited to a non-aqueous electrolyte secondary battery, but may be a secondary battery other than a non-aqueous electrolyte secondary battery, a capacitor, or a battery using a solid electrolyte. The energy storage element 60 may be a primary battery instead of a secondary battery. The energy storage element 60 does not need to be a pouch-type energy storage element, but may be an energy storage element in the shape of a flat rectangular parallelepiped (square), etc. A rectangular parallelepiped as used here is a hexahedron in which all faces are rectangles or squares.

[0034] In this embodiment, the energy storage device 1 includes an outer casing 10 that houses the energy storage unit 50 and the restraining member 200. The outer casing 10 is a box-shaped (approximately rectangular parallelepiped) container (module case) that constitutes the housing of the energy storage device 1. In Figure 1, the opening in the Z-axis positive direction of the outer casing 10 is exposed, but the outer casing 10 may also include a lid to close the opening.

[0035] More specifically, the energy storage device 1 according to this embodiment comprises two energy storage units 50 housed in an outer casing 10 and aligned in the X-axis direction. Each of the two energy storage units 50 is constrained by a restraining member 200. These two energy storage units 50 have the same configuration. Therefore, in the following description, we will mainly focus on the energy storage unit 50 in the X-axis positive direction and explain the configuration of the energy storage unit 50 and its surroundings.

[0036] The energy storage unit 50 comprises a plurality of trays 100, including a tray 150 which is the end tray 100 in the positive Y-axis direction. The trays 100 other than tray 150 have portions that can be connected to the trays 100 in the positive Y-axis direction and the negative Y-axis direction of the tray 100. Since tray 150 is located at the end of the energy storage unit 50 in the positive Y-axis direction, it has portions that can be connected to the tray 100 in the negative Y-axis direction and is formed to a different size from the other trays 100. In this embodiment, each of the seven trays 100 is connected to the adjacent tray 100 in the Y-axis direction, thereby connecting the seven trays 100 in the Y-axis direction. The detailed configuration of the trays 100 will be described later with reference to Figures 3A to 8.

[0037] The restraining member 200 comprises a pair of end members 210 that sandwich the energy storage unit 50 in the Y-axis direction, and a wire 250 connecting the pair of end members 210, the wire 250 being flexible. When distinguishing between the pair of end members 210, the end member 210 in the negative Y-axis direction is referred to as end member 210A, and the end member 210 in the positive Y-axis direction is referred to as end member 210B. In this embodiment, each of the end members 210A and 210B is a plate-shaped member made of a metal such as iron or an aluminum alloy. As the material for the end members 210A and 210B, carbon fiber reinforced plastics (CFRP) or a composite material of lightweight CFRP and a foamed molded body may be used. This allows the end members 210A and 210B to have a predetermined strength, while also reducing their weight.

[0038] The end member 210A in this embodiment also serves as a side wall portion in the negative Y-axis direction of the outer casing 10 (see Figure 1). The end member 210A is used to restrain two energy storage units 50 aligned in the X-axis direction in the Y-axis direction. In other words, in this embodiment, the end member 210A is shared by two restraining members 200 aligned in the X-axis direction. It is not essential that the end member 210A has these features; that is, the end member 210A does not need to be used as a side wall portion of the outer casing 10, nor does it need to be shared by two restraining members 200. The end member 210A may be a separate component from the outer casing 10, or it may be a component that is only involved in restraining the energy storage units 50 in the positive X-axis direction.

[0039] A pair of end members 210 are connected by two wires 250. The wires 250 are ropes formed by bundling linear materials made of metal such as stainless steel. The wires 250 are also called "wire ropes". Because the wires 250 are flexible, they can be easily bent as shown in Figures 2A and 2B. The material of the wires 250 is not limited to metal. At least a portion of the material of the wires 250 may be carbon fiber or glass fiber, which have relatively high tensile strength.

[0040] The wire 250 according to this embodiment includes screw shaft portions 255 that can be coupled to nuts 219 at both end portions in the direction in which the wire 250 extends. As shown in FIGS. 2A and 2B, the wire 250 is inserted into groove portions 214 at both ends in the X-axis direction of the end member 210B, and the two screw shaft portions 255 are directed in the negative Y-axis direction. Each of the two screw shaft portions 255 passes through a guide hole 141 provided in a guide portion 140 of a plurality of trays 100, passes through a fixing hole 216 of the end member 210A, and is coupled to the nut 219. In this state, by adjusting the tightening degree of the nut 219 (the number of rotations of the nut 219 when coupled to the screw shaft portion 255), the compressive force in the Y-axis direction applied to the power storage unit 50 by the pair of end members 210 can be adjusted. The restraint member 200 according to this embodiment includes two wires 250 that connect a pair of end members 210, and the two wires 250 are arranged vertically as shown in FIGS. 2A and 2B.

[0041] In FIGS. 2A and 2B, a structure in which the power storage unit 50 in the positive X-axis direction is restrained by the restraint member 200 is shown. Similarly, the power storage unit 50 in the negative X-axis direction (see FIG. 1) is also restrained in the Y-axis direction by the restraint member 200.

[0042] In the power storage device 1 configured as described above, a plurality of trays 100 each accommodating one or more power storage elements 60 are arranged in a state of being connected in the Y-axis direction. Hereinafter, the configuration of the tray 100 and its surroundings will be described in detail while referring to FIGS. 3A to 8.

[0043] [2. Configuration of Tray 100] First, the configuration of the tray 100 according to the embodiment will be described using FIGS. 3A to 3C. FIG. 3A is a first perspective view showing the configuration of the tray 100 according to the embodiment. FIG. 3B is a second perspective view showing the configuration of the tray 100 according to the embodiment. FIG. 3C is a perspective view showing the configuration of the tray 150 according to the embodiment. The tray 150 is the tray 100 at the end in the positive Y-axis direction of the power storage unit 50 as described above.

[0044] As shown in FIGS. 3A to 3C, the tray 100 according to the embodiment includes a tray body 101 facing the power storage element 60 in the Y-axis direction, a protruding portion 110 protruding in the +Y-axis direction from the tray body 101, and an insertion portion 120 formed by a cavity inside the protruding portion 110. The insertion portion 120 opens in the -Y-axis direction.

[0045] The tray body 101 has a main body protruding portion 104 protruding in the -Y-axis direction. Inside the main body protruding portion 104 (in the +Y-axis direction), a housing recess 105 for housing a part of the power storage element 60 in the Y-axis direction is formed.

[0046] The protruding portion 110 is formed so as to surround the power storage element 60 from three directions: the -Z-axis direction, the +X-axis direction, and the -X-axis direction. Specifically, as shown in FIG. 3B, the protruding portion 110 includes a lower wall forming portion 111 extending in the X-axis direction and two side wall forming portions 112 extending in the Z-axis direction. The lower wall forming portion 111 is connected to an end portion of the tray body 101 in the -Z-axis direction. One of the two side wall forming portions 112 is connected to an end portion of the tray body 101 in the +X-axis direction, and the other of the two side wall forming portions 112 is connected to an end portion of the tray body 101 in the -X-axis direction. In the present embodiment, a cell housing portion 130 for housing one or more power storage elements 60 is formed by the space surrounded by the lower wall forming portion 111 and the two side wall forming portions 112. In the present embodiment, four power storage elements 60 are housed in the cell housing portion 130 of the tray 100.

[0047] In the present embodiment, four power storage elements 60 housed in one tray 100 are connected in parallel to form one group of power storage elements 60. That is, the power storage unit 50 includes seven groups of power storage elements 60. These seven groups of power storage elements 60 are connected in series. The electrical connection form of the 28 power storage elements 60 included in the power storage unit 50 is not particularly limited, and the 28 power storage elements 60 may be connected in series and / or in parallel in any combination.

[0048] The protruding portion 110 configured as described above is inserted into the insertion portion 120 of another tray 100 disposed in the +Y-axis direction of the protruding portion 110.

[0049] Since the protruding portion 110 has a shape that bulges out in the positive Y-axis direction as a whole, a cavity is formed inside the protruding portion 110. In the tray 100 according to this embodiment, the insertion portion 120 is formed by the cavity inside the protruding portion 110. As shown in Figures 3A and 3C, the insertion portion 120 includes a lower insertion portion 121 extending in the X-axis direction and two side insertion portions 122 connected to each of the X-axis ends of the lower insertion portion 121 and extending in the Z-axis direction. The lower insertion portion 121 is formed by the cavity inside the lower wall forming portion 111 of the protruding portion 110, and the two side insertion portions 122 are formed by the cavities inside the two side wall forming portions 112 of the protruding portion 110. The protruding portion 110 of another tray 100, which is positioned in the negative Y-axis direction of the insertion portion 120, is inserted into the insertion portion 120 configured in this way.

[0050] More specifically, the protruding portion 110 has a convex portion 116 that protrudes in a direction intersecting the Y-axis direction and extends in the Y-axis direction. A recess 117 is formed inside the convex portion 116, as shown in Figures 3A and 3C. In other words, the insertion portion 120 has a recess 117. The lower wall forming portion 111 of the protruding portion 110 has a plurality of convex portions 116 arranged in the X-axis direction. Each of the plurality of convex portions 116 protrudes in the Z-axis positive direction and extends in the Y-axis direction. The two side wall forming portions 112 of the protruding portion 110 have a plurality of convex portions 116 arranged in the Z-axis direction. Each of the plurality of convex portions 116 formed on the side wall forming portion 112 in the X-axis positive direction protrudes in the X-axis positive direction and extends in the Y-axis direction. Each of the plurality of convex portions 116 formed on the side wall forming portion 112 in the X-axis negative direction protrudes in the X-axis negative direction and extends in the Y-axis direction. A recess 117 is formed inside each of these multiple protrusions 116. When the protruding portion 110 is inserted into the insertion portion 120 of another tray 100 arranged in the Y-axis positive direction, each of the multiple protrusions 116 of the protruding portion 110 is inserted into the recess 117 of the other tray 100.

[0051] In the tray 100 according to this embodiment, guide portions 140 are provided at both ends of the tray body 101 in the X-axis direction. The guide portion 140 provided in the X-axis positive direction of the tray body 101 protrudes from the tray body 101 in the X-axis positive direction and has two guide holes 141 aligned in the Z-axis direction. The guide portion 140 provided in the X-axis negative direction of the tray body 101 protrudes from the tray body 101 in the X-axis negative direction and has two guide holes 141 aligned in the Z-axis direction. A wire 250 is arranged to pass through each of these multiple guide holes 141, as shown in Figures 2A and 2B.

[0052] As shown in Figure 3C, tray 150, which is the tray 100 at the positive Y-axis end of the energy storage unit 50, has a configuration common to the other trays 100 (see Figures 3A and 3B), except that the length of the protrusion 110 in the Y-axis direction is shorter. In other words, four energy storage elements 60 are housed in the cell housing portion 130 of tray 150. The protrusion 110 of tray 100, which is positioned in the negative Y-axis direction of tray 150, is inserted into the insertion portion 120 formed by the cavity inside the protrusion 110 of tray 150. This connects tray 100 and tray 150.

[0053] [3. Connecting Structure of Tray 100] The structure in which the trays 100 configured as described above are connected in the Y-axis direction will be explained with reference to Figures 4 to 8. Figure 4 is an exploded perspective view of a part of the energy storage unit 50 according to the embodiment. In Figure 4, two adjacent trays 100 in the Y-axis direction and four energy storage elements 60 arranged between the two trays 100 are shown in a perspective view. Figure 5 is a front view (viewed from the positive Y-axis direction) showing the positional relationship between the trays 100 and the energy storage elements 60 according to the embodiment. Figure 6 is a rear view (viewed from the negative Y-axis direction) showing the positional relationship between the trays 100 and the energy storage elements 60 according to the embodiment. In Figure 6, the outer edge of the container 61 of the energy storage elements 60 housed in the trays 100 is shown by a rectangular dashed line. Figure 7 is a first cross-sectional view of the two trays 100 and the eight energy storage elements 60 housed in the two trays 100 according to the embodiment. Figure 8 is a second cross-sectional view of two trays 100 and eight energy storage elements 60 housed in the two trays 100 according to the embodiment. In Figures 7 and 8, the cross-sections of the two trays 100 and eight energy storage elements 60 are simply illustrated in a cross-sectional view parallel to the YZ plane passing through the line VII-VII in Figure 4. In Figure 7, the two trays 100 connected in the Y-axis direction are shown in a cross-sectional view separated in the Y-axis direction. In Figure 7, the four energy storage elements 60 housed in the tray 100 in the negative Y-axis direction (second tray 100B) are shown separated in the Y-axis direction. In Figure 8, the two trays 100 are shown in a cross-sectional view connected in the Y-axis direction.

[0054] In Figures 4 to 8 and the following description, when distinguishing between two trays 100 aligned in the Y-axis direction, the tray 100 in the positive Y-axis direction is referred to as the first tray 100A, and the tray 100 in the negative Y-axis direction is referred to as the second tray 100B. In other words, of the seven trays 100, one of two arbitrarily selected adjacent trays 100 in the Y-axis direction is the first tray 100A, and the other is the second tray 100B. The first tray 100A may also be the tray 150 at the positive Y-axis end of the energy storage unit 50.

[0055] The names of the main components of the first tray 100A are preceded by "First" and the letter "A" is added to the end of their symbols. The names of the main components of the second tray 100B are preceded by "Second" and the letter "B" is added to the end of their symbols. The tray body 101, protrusion 110, and insertion part 120 of the first tray 100A are referred to in this order as the first tray body 101A, the first protrusion 110A, and the first insertion part 120A. The tray body 101, protrusion 110, and insertion part 120 of the second tray 100B are referred to in this order as the second tray body 101B, the second protrusion 110B, and the second insertion part 120B.

[0056] In this embodiment, as shown in Figure 4, four energy storage elements 60 are arranged between the first tray 100A and the second tray 100B, which are adjacent in the Y-axis direction. The energy storage elements 60 in this embodiment are pouch-type energy storage elements having a flattened shape in the Y-axis direction, as described above. The energy storage element 60 comprises a container 61 and a pair of terminals 62 (positive and negative) that protrude from the Z-axis positive end of the container 61 and are aligned in the X-axis direction. When distinguishing between the pair of terminals 62, the positive terminal 62 is referred to as terminal 62a, and the negative terminal 62 is referred to as terminal 62b.

[0057] In this embodiment, in each of the four energy storage elements 60, the terminal 62 in the positive X-axis direction of the pair of terminals 62 is the positive terminal 62a, and the terminal 62 in the negative X-axis direction of the pair of terminals 62 is the negative terminal 62b. That is, the four terminals 62a are aligned in the Y-axis direction, and the four terminals 62b are aligned in the Y-axis direction. In this embodiment, the four terminals 62a are connected by a conductive material such as a busbar or a flexible printed circuit board (FPC), and the four terminals 62b are connected by a conductive material such as a busbar or FPC. In other words, the four energy storage elements 60 are connected in parallel.

[0058] The container 61 contains an electrode body and an electrolyte, etc., which are not shown. In this embodiment, a stacked electrode body is used, which is formed by stacking a plurality of flat electrode plates (positive electrode plate and negative electrode plate). The electrode body of the energy storage element 60 may be of any form, such as a wound electrode body formed by winding electrode plates, or a bellows-type electrode body in which electrode plates are folded in a bellows shape. As for the electrolyte of the energy storage element 60, there are no particular restrictions on the type as long as it does not impair the performance of the energy storage element 60, and any known material can be used as appropriate. The container 61 is a sheet-like outer casing made of laminate film, and is also called an "outer film," etc. The container 61 contains the electrode body and electrolyte, etc., sealed inside under reduced pressure. A cell projection 65 that protrudes in the Z-axis direction is formed in the center of the container 61, and the electrode body is housed inside the cell projection 65. The back surface 66 of the container 61, opposite to the cell protrusion 65, forms a relatively flat surface.

[0059] In this embodiment, as shown in Figures 4, 7, and 8, of the four energy storage elements 60 housed in the tray 100, the first and third energy storage elements 60 from the positive Y-axis direction are arranged with their cell protrusions 65 facing the positive Y-axis direction. The second and fourth energy storage elements 60 from the positive Y-axis direction are arranged with their cell protrusions 65 facing the negative Y-axis direction. As a result, of the four energy storage elements 60, the first and second energy storage elements 60 from the positive Y-axis direction are arranged with their back surfaces 66 facing each other in the Y-axis direction, and the third and fourth energy storage elements 60 from the positive Y-axis direction are also arranged with their back surfaces 66 facing each other in the Y-axis direction. Of the four energy storage elements 60, the second and third energy storage elements 60 from the positive Y-axis direction are arranged with their cell protrusions 65 facing each other in the Y-axis direction.

[0060] In the tray 100 that houses the energy storage element 60 configured as described above, the protruding portion 110 and the insertion portion 120 provided by the tray 100 are arranged along the outer edge of the container 61 of the energy storage element 60 housed in the tray 100.

[0061] As shown in Figure 5, when the first tray 100A is viewed from the positive Y-axis direction, the container 61 of the energy storage element 60 is rectangular (including substantially rectangular, the same applies hereinafter). That is, the outer edge of the rectangular container 61 includes four sides. The four sides consist of a bottom side located in the negative Z-axis direction and extending in the X-axis direction, a top side located in the positive Z-axis direction and extending in the X-axis direction, a left side located in the positive X-axis direction and extending in the Z-axis direction, and a right side located in the negative X-axis direction and extending in the Z-axis direction. The first protrusion 110A extends along at least three of these four sides. In this embodiment, as described above, the first protrusion 110A includes a bottom wall forming portion 111 extending in the X-axis direction and two side wall forming portions 112 extending in the Z-axis direction. That is, the first protrusion 110A extends along the bottom, left, and right sides of the outer edge of the rectangular container 61. The first insertion portion 120A of the first tray 100A is formed by the cavity inside the first protrusion 110A. Therefore, as shown in Figure 6, the first insertion portion 120A also extends along the bottom edge, left edge, and right edge of the outer edge of the rectangular container 61. The first tray 100A and the second tray 100B have the same shape. Therefore, the second protrusion 110B and the second insertion portion 120B of the second tray 100B similarly extend along the bottom edge, left edge, and right edge of the outer edge of the container 61 of the energy storage element 60.

[0062] The first tray 100A, which houses four energy storage elements 60, and the second tray 100B, which also houses four energy storage elements 60, configured as described above, are connected as shown in Figures 7 and 8. Specifically, the first tray 100A and the second tray 100B are connected by inserting the second protruding portion 110B of the second tray 100B into the first insertion portion 120A of the first tray 100A. Figures 7 and 8 show the state in which the lower wall forming portion 111 of the second protruding portion 110B is inserted into the lower insertion portion 121 of the first insertion portion 120A. In this state, the side wall forming portion 112 (see Figure 3B) of the second protruding portion 110B, which is located opposite in the Y-axis direction, is inserted into the side insertion portion 122 (see Figures 3A and 3C) of the first insertion portion 120A.

[0063] When the first tray 100A and the second tray 100B are connected, as shown in Figure 8, the four energy storage elements 60 housed in the first tray 100A are sandwiched in the Y-axis direction by the first tray body 101A of the first tray 100A and the second tray body 101B of the second tray 100B. More specifically, the energy storage unit 50, including the configuration shown in Figures 7 and 8, is restrained in the Y-axis direction by a restraining member 200, as shown in Figures 1, 2A, and 2B. The restraining member 200 comprises a pair of end members 210 that sandwich the energy storage unit 50 in the Y-axis direction and a wire 250 that connects the pair of end members 210. As a result, the four energy storage elements 60 housed in the first tray 100A can receive a balanced compressive force in the Y-axis direction within the XZ plane. This suppresses expansion in the Y-axis direction.

[0064] In this embodiment, the cell protrusion 65 of the energy storage element 60 closest to the second tray body 101B of the first tray 100A is housed in a receiving recess 105 (see Figures 3B, 7, and 8) provided in the second tray body 101B. As a result, the energy storage element 60 closest to the second tray body 101B is restricted from moving in the Y-axis, Z-axis, and X-axis directions by the second tray 100B. An adhesive member (such as double-sided adhesive tape), not shown in Figure 7, is placed between two adjacent energy storage elements 60 in the Y-axis direction. As a result, two adjacent energy storage elements 60 in the Y-axis direction are bonded together, and the four energy storage elements 60 are integrated. Therefore, the movement of the four energy storage elements 60 in the Y-axis, Z-axis, and X-axis directions is restricted by the second tray 100B.

[0065] An adhesive member, such as double-sided adhesive tape, may be placed between the energy storage element 60 closest to the second tray body 101B and the housing recess 105 of the second tray body 101B. An adhesive member, such as double-sided adhesive tape, may also be placed between the energy storage element 60 closest to the first tray body 101A and the body protrusion 104 of the first tray body 101A. Adhesive foam material or sheets may be used as these adhesive members. By placing adhesive foam material (such as acrylic foam) between two adjacent energy storage elements 60, misalignment of one of the two energy storage elements 60 relative to the other is suppressed, and / or the pressure in the XZ plane is made uniform.

[0066] The technical features of the energy storage device 1 according to the embodiment configured as described above are explained below.

[0067] The energy storage device 1 according to this embodiment comprises a first tray 100A and a second tray 100B arranged in the Y-axis direction, and an energy storage element 60 positioned between the first tray 100A and the second tray 100B. The first tray 100A comprises a first tray body 101A facing the energy storage element 60 in the Y-axis direction, a first protruding portion 110A protruding from the first tray body 101A to one side in the Y-axis direction (the positive Y-axis direction in this embodiment), and a first insertion portion 120A formed by a cavity inside the first protruding portion 110A. The first insertion portion 120A opens to the other side in the Y-axis direction (the negative Y-axis direction in this embodiment). The second tray 100B comprises a second tray body 101B facing the energy storage element 60 in the Y-axis direction, and a second protruding portion 110B protruding in the positive Y-axis direction. The second protruding portion 110B is inserted into the first insertion portion 120A.

[0068] As described above, in this embodiment, the second protrusion 110B of the second tray 100B is inserted into the first insertion portion 120A of the first tray 100A, thereby suppressing the displacement of the first tray 100A and the second tray 100B relative to one of them (movement in a direction intersecting the Y-axis direction, the same applies hereinafter). Therefore, displacement of the second tray 100B in the Z-axis direction and / or X-axis direction relative to the first tray 100A due to vibration or shock applied to the energy storage device 1 is suppressed. As a result, malfunctions in the energy storage element 60 caused by displacement of the second tray 100B in the Z-axis direction and / or X-axis direction are suppressed. Thus, the first insertion portion 120A used to connect the first tray 100A and the second tray 100B, which are two trays 100 aligned in the Y-axis direction, is formed using the internal space (cavity) of the first protrusion 110A. Therefore, the configuration of the first tray 100A is simplified compared to the case where the first protrusion 110A and the first insertion portion 120A are arranged in different positions. Therefore, the energy storage device 1 according to this embodiment is an energy storage device with a simple configuration and improved reliability.

[0069] More specifically, in the tray 100 according to this embodiment, a cavity is formed inside the protruding portion 110, which is formed to bulge out in the positive Y-axis direction, and the insertion portion 120 is formed by this cavity. Therefore, at least a portion of the arrangement range of the protruding portion 110 in the Y-axis direction overlaps with at least a portion of the arrangement range of the insertion portion 120 in the Y-axis direction. When viewed from the Y-axis direction, the arrangement range of the insertion portion 120 is included in the arrangement range of the protruding portion 110. Therefore, the configuration of the tray 100 is simplified compared to the case where the arrangement ranges of the protruding portion 110 and the insertion portion 120 in the Y-axis direction do not overlap, and / or the arrangement ranges of the protruding portion 110 and the insertion portion 120 when viewed from the Y-axis direction do not overlap.

[0070] In this embodiment, as shown in Figures 7 and 8, the first protrusion 110A and the first insertion portion 120A have a tapered shape in which the width in the direction intersecting the Y-axis direction decreases as they advance in the Y-axis positive direction. The second protrusion 110B has a tapered shape corresponding to the first insertion portion 120A.

[0071] With this configuration, the second protrusion 110B is easily inserted into the first insertion portion 120A, and movement of the second protrusion 110B in the direction of withdrawing from the first insertion portion 120A is easily permitted. In other words, when the energy storage element 60 expands, movement of the second tray 100B in the direction of moving away from the first tray 100A is easily permitted. This suppresses excessive pressure on the energy storage element 60 between the first tray 100A and the second tray 100B.

[0072] In this embodiment, the protruding portion 110 of the tray 100 is configured to be deeply inserted into the insertion portion 120 of another tray 100 located in the positive Y-axis direction. As shown in Figure 8, in the Y-axis direction, the tip of the second protruding portion 110B is located further in the positive Y-axis direction than the first tray body 101A.

[0073] In other words, in the state where the first tray 100A and the second tray 100B are connected in the Y-axis direction, the length of the second protrusion 110B of the second tray 100B that is inserted into the first insertion part 120A is relatively long. Therefore, even if the second protrusion 110B moves relatively large in the direction of being withdrawn from the first insertion part 120A (negative Y-axis direction), at least a part of the second protrusion 110B remains inserted into the first insertion part 120A. In other words, the displacement of one tray 100A and the other tray 100B relative to the other is suppressed.

[0074] More specifically, in this embodiment, as shown in Figure 8, the tip of the second projection 110B is located in the same position as, or further in the positive Y-axis direction than, the edges of the four energy storage elements 60 housed in the first tray 100A, in the positive Y-axis direction. Therefore, the second cell housing portion 130B of the second tray 100B accommodates not only the four energy storage elements 60 arranged between the first tray 100A and the second tray 100B, but also the four energy storage elements 60 arranged in the first cell housing portion 130A of the first tray 100A. In other words, it can also be explained that the second tray 100B accommodates a total of eight energy storage elements 60.

[0075] Thus, in this embodiment, in the second tray 100B, one or more energy storage elements 60 arranged between the first tray 100A and the second tray 100B are housed in the second cell housing portion 130B located laterally to the second protrusion 110B in a direction intersecting the Y-axis direction. One or more energy storage elements 60 housed in the first cell housing portion 130A of the first tray 100A are housed in the second cell housing portion 130B of the second tray 100B together with a part of the first tray 100A. In this way, the tray 100 according to this embodiment is equipped with a relatively long protrusion 110 and insertion portion 120 in the arrangement direction of the energy storage elements 60 (Y-axis direction). Therefore, when two adjacent trays 100 are connected in the Y-axis direction, the contact area between the two trays 100 is relatively large. As a result, the resistance of the energy storage unit 50, which has a structure in which multiple trays 100 are connected in the Y-axis direction, to vibration or shock is improved.

[0076] In this embodiment, the energy storage element 60 includes a container 61 for housing the electrode body. When viewed from the Y-axis direction, the first protrusion 110A, the first insertion portion 120A, and the second protrusion 110B extend along the outer edge of the container 61.

[0077] In this way, the first insertion portion 120A and the second protrusion portion 110B extend along the outer edge of the energy storage element 60, so that the connection portion between the first insertion portion 120A and the second protrusion portion 110B is formed along the outer edge of the energy storage element 60. As a result, the displacement of one of the first tray 100A and the second tray 100B relative to the other is suppressed more stably.

[0078] More specifically, as shown in Figures 5 and 6, the outer edge of the container 61 is rectangular when viewed from the Y-axis direction. When viewed from the Y-axis direction, the first projection 110A, the first insertion portion 120A, and the second projection 110B extend along at least three of the four sides that form the outer edge of the container 61. In this embodiment, the first projection 110A, the first insertion portion 120A, and the second projection 110B extend along the bottom, left, and right sides of the four sides that form the outer edge of the container 61.

[0079] Thus, in this embodiment, the connection portion between the second protrusion 110B and the first insertion portion 120A is provided over a wide area along the outer edge of the container 61 of the energy storage element 60. This connection portion includes portions along sides that extend in different directions. As a result, the displacement of the first tray 100A and the second tray 100B relative to one of them is stably suppressed.

[0080] Specifically, in this embodiment, the lower wall forming portion 111 of the second projection 110B and the lower insertion portion 121 of the first insertion portion 120A extend along the lower edge of the rectangular outer edge of the container 61. The lower wall forming portion 111 of the second projection 110B is inserted into the lower insertion portion 121 of the first insertion portion 120A. This stably suppresses the displacement of the first tray 100A and the second tray 100B relative to one, and the displacement in the Z-axis direction. The side wall forming portion 112 of the second projection 110B and the side insertion portion 122 of the first insertion portion 120A extend along the right and left edges, respectively, of the rectangular outer edge of the container 61. The side wall forming portion 112 of the second projection 110B is inserted into the side insertion portion 122 of the first insertion portion 120A. This stably suppresses the displacement of the first tray 100A and the second tray 100B relative to one, specifically the displacement in the X-axis direction. In other words, by inserting the second protrusion 110B into the first insertion part 120A, the displacement of the first tray 100A and the second tray 100B relative to one, specifically the displacement in the Z-axis direction and the X-axis direction, is suppressed.

[0081] In this embodiment, as shown in Figures 4 to 6, the first projection 110A protrudes in a direction intersecting the Y-axis direction and includes a first convex portion 116A extending in the Y-axis direction. The first insertion portion 120A is a first recess 117A formed inside the first convex portion 116A and includes a first recess 117A extending in the Y-axis direction. The second projection 110B includes a second convex portion 116B extending in the Y-axis direction. The second convex portion 116B is inserted into the first recess 117A.

[0082] In other words, when the second projection 110B is inserted into the first insertion part 120A, the second protrusion 116B of the second projection 110B, which protrudes in the Z-axis direction or the X-axis direction and extends in the Y-axis direction, is inserted into the first recess 117A which extends in the Y-axis direction. With this configuration, the insertion of the second protrusion 116B of the second projection 110B into the first recess 117A of the first insertion part 120A restricts the movement of one of the first tray 100A and the second tray 100B relative to the other in the direction in which the second protrusion 116B extends (Y-axis direction) and in the direction intersecting the protruding direction of the second protrusion 116B. The insertion of the second protrusion 116B, which protrudes in the X-axis positive direction, into the first recess 117A which is recessed in the X-axis positive direction restricts the movement of one of the first tray 100A and the second tray 100B relative to the other in the Z-axis direction. Therefore, the displacement of the first tray 100A and the second tray 100B relative to one of them is stably suppressed. The protrusion 116 provided on the protrusion 110 of the tray 100 may function as a part that improves the rigidity of the protrusion 110.

[0083] In this embodiment, the energy storage unit 50 is restrained by a restraining member 200, as shown in Figures 1, 2A, and 2B. That is, the energy storage device 1 comprises a first tray 100A, a second tray 100B, and a pair of end members 210 that sandwich the energy storage unit 50, which includes the energy storage element 60, in the Y-axis direction, and a flexible wire 250 that connects the pair of end members 210.

[0084] With this configuration, the pair of end members 210 can compress the end faces of the energy storage unit 50 in the positive and negative Y-axis directions. Therefore, the energy storage element 60 can be compressed more uniformly in a plane intersecting the Y-axis direction (the XZ plane in this embodiment). Since the wire 250 is flexible, it can restrain the energy storage unit 50 in the Y-axis direction while easily allowing the energy storage element 60 to bulge. Consequently, excessive compression of the energy storage element 60 by the pair of end members 210 in the Y-axis direction is suppressed. As a result, the occurrence of problems such as deterioration of the performance of the energy storage element 60 caused by uneven or excessive compression force on the energy storage element 60 in the XZ plane is suppressed.

[0085] In this embodiment, as shown in Figures 4 to 6, the first tray 100A is provided with a first guide portion 140A having a first guide hole 141A through which the wire 250 passes. The second tray 100B is provided with a second guide portion 140B having a second guide hole 141B through which the wire 250 passes.

[0086] With this configuration, the wire 250 more reliably prevents one of the first tray 100A and the second tray 100B from shifting in a direction intersecting the Y-axis direction relative to the other of the first tray 100A and the second tray 100B. The wire 250 is guided by the first guide portion 140A and the second guide portion 140B, which suppresses the bending of the flexible wire 250 when attaching the restraint member 200 to the energy storage unit 50. As a result, the attachment of the restraint member 200 to the energy storage unit 50 can be performed efficiently. In this embodiment, as shown in Figures 1, 2A, and 2B, a plurality of trays 100 arranged in the Y-axis direction are provided with guide portions 140 through which the wire 250 passes. In other words, the wire 250 is positioned to pass through the guide portions 140 of all the trays 100 provided in the energy storage unit 50.

[0087] [4. Modifications] Although the energy storage device 1 according to the embodiment has been described above, the present invention is not limited to the embodiment. That is, 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.

[0088] The energy storage device 1 does not necessarily have an outer casing 10. The energy storage device 1 may be an energy storage device (energy storage module) that comprises a first tray 100A and a second tray 100B, and one or more energy storage elements 60 arranged between the first tray 100A and the second tray 100B, and does not have an outer casing 10.

[0089] The protruding portion 110 and insertion portion 120 of the tray 100 do not have to be tapered as shown in Figures 7 and 8. There are no particular limitations on the shape of the second protruding portion 110B and the first insertion portion 120A, as long as a portion of about half the length of the second protruding portion 110B in the Y-axis direction can be inserted into the first insertion portion 120A.

[0090] The length of the projection 110 of the tray 100 in the Y-axis direction is not limited to the length shown in Figures 3A and 3B, etc. In Figure 8, the tip of the second projection 110B is located in the positive Y-axis direction relative to the first tray body 101A in the Y-axis direction, but this is not essential. The tip of the second projection 110B and the first tray body 101A may be at the same position in the Y-axis direction, or the tip may be located in the negative Y-axis direction relative to the first tray body 101A. Assume that the portion of the first tray 100A that forms the first insertion portion 120A protrudes in the negative Y-axis direction relative to the first tray body 101A. In this case, even if the tip of the second projection 110B is located in the negative Y-axis direction relative to the first tray body 101A, it is still possible to insert at least a part of the second projection 110B into the first insertion portion 120A.

[0091] The protruding portion 110 and insertion portion 120 of the tray 100 do not need to extend along the outer edge of the container 61 of the energy storage element 60. If the outer edge of the container 61 is rectangular, the protruding portion 110 and insertion portion 120 may have a curved shape such as an arc shape or a C shape when viewed from the Y-axis direction.

[0092] When viewed from the Y-axis direction, the outer edge of the container 61 containing the energy storage element 60 does not have to be rectangular. The outer edge of the container 61 may be a polygon, circle, oval, or ellipse other than a rectangle. Even in this case, each of the multiple trays 100 can accommodate one or more energy storage elements 60.

[0093] The protruding portion 110 does not necessarily have to include a lower wall forming portion 111 extending in the X-axis direction and two side wall forming portions 112 extending in the Z-axis direction. The protruding portion 110 may consist of only one or two of the lower wall forming portion 111 and the two side wall forming portions 112. In other words, the insertion portion 120 may be formed by the cavity inside the lower wall forming portion 111 and one or two of the two side wall forming portions 112. Even in this case, the second protruding portion 110B of the second tray 100B and the first insertion portion 120A of the first tray 100A face each other in the Y-axis direction. Therefore, the second protruding portion 110B can be inserted into the first insertion portion 120A. As a result, the first tray 100A and the second tray 100B are connected.

[0094] It is not essential that the protruding portion 110 has one or more protrusions 116 (see Figures 3A to 3C). It is not essential that the insertion portion 120 has one or more recesses 117 (see Figures 3A to 3C). Even if the protruding portion 110 does not have protrusions 116 and the insertion portion 120 does not have recesses 117, two trays 100 aligned in the Y-axis direction can be connected. In other words, the second protruding portion 110B of the second tray 100B can be inserted into the first insertion portion 120A of the first tray 100A.

[0095] The configuration of the restraining member 200 that restrains the energy storage unit 50 in the Y-axis direction is not limited to the configurations shown in Figures 1, 2A, and 2B. In the restraining member 200, the pair of end members 210 may be connected by only one wire 250. The wire 250 arranged in the X-axis positive direction of the energy storage unit 50 and the wire 250 arranged in the X-axis negative direction of the energy storage unit 50 may be separate from each other. The member connecting the pair of end members 210 is not limited to a wire 250. The pair of end members 210 may be connected by a plate-shaped or rod-shaped metal body or the like. However, from the viewpoint of suppressing expansion of the energy storage element 60 in the Y-axis direction and preventing excessive force from compressing the energy storage element 60, it is preferable to connect the pair of end members 210 with a flexible wire 250.

[0096] The guide portion 140 of the tray 100 may have a notch for passing the wire 250 in the Y-axis direction instead of a guide hole 141. It is not essential that the tray 100 has a guide portion 140. In other words, the wire 250 may be positioned relative to the energy storage unit 50 without being guided by the guide portions 140 of the tray 100 which are aligned in the Y-axis direction.

[0097] The energy storage device 1 does not necessarily have to be equipped with a restraining member 200. If the energy storage device 1 does not have a restraining member 200, the connection strength between the first tray 100A and the second tray 100B may be ensured by press-fitting the second protruding portion 110B of the second tray 100B into the first insertion portion 120A of the first tray 100A. If the energy storage device 1 does not have a restraining member 200, the movement of both ends of the energy storage unit 50 in the Y-axis direction may be restricted by the walls or protrusions of the case or rack in which the energy storage device 1 is arranged.

[0098] The positions of the two terminals 62 of the energy storage element 60 are not limited to those shown in Figure 4. The two terminals 62 may be located at the end of the container 61 in the positive X-axis direction. In this case, the protruding portion 110 of the tray 100 does not have a side wall forming portion 112 (see Figure 3B) in the positive X-axis direction, allowing for easy connection of each of the two terminals 62 to a conductive member such as a busbar. One of the two terminals 62 may be located at the end of the container 61 in the positive Z-axis direction, and the other terminal 62 may be located at the end of the container 61 in the negative Z-axis direction. In this case, the protruding portion 110 of the tray 100 does not have a bottom wall forming portion 111 (see Figure 3B), allowing for easy connection of each of the two terminals 62 to a conductive member such as a busbar.

[0099] The tray body 101 of the tray 100 does not need to have a receiving recess 105 that accommodates a portion of the energy storage element 60 in the Y-axis direction. In other words, the tray body 101 does not need to play a role in restricting the movement of the energy storage element 60 in the XZ plane. In this case, the protrusion 110 of the tray 100 may play a role in supporting the energy storage element 60, or in other words, in restricting the movement of the energy storage element 60 in the XZ plane. That is, one or more energy storage elements 60 may be housed in the tray 100 in contact with the protrusion 110.

[0100] The present invention also includes forms constructed by arbitrarily combining the components included in the above embodiments and their supplementary provisions.

[0101] This invention can be applied to energy storage devices equipped with energy storage elements such as lithium-ion secondary batteries.

[0102] 1. Energy storage device 50. Energy storage unit 60. Energy storage element 61. Container 100, 150. Tray 100A. First tray 100B. Second tray 101. Tray body 101A. First tray body 101B. Second tray body 110. Protrusion 110A. First protrusion 110B. Second protrusion 116. Convex part 116A. First convex part 116B. Second convex part 117. Recess 117A. First recess 120. Insertion part 120A. First insertion part 120B. Second insertion part 140. Guide part 140A. First guide part 140B. Second guide part 141. Guide hole 141A. First guide hole 141B. Second guide hole 200. Restraining member 210, 210A, 210B. End member 250. Wire

Claims

1. An energy storage device comprising: a first tray and a second tray arranged in a first direction; and an energy storage element disposed between the first tray and the second tray, wherein the first tray comprises: a first tray body facing the energy storage element in the first direction; a first projection protruding from the first tray body to one side in the first direction; and a first insertion portion formed by a cavity inside the first projection and opening to the other side in the first direction, wherein the second tray comprises: a second tray body facing the energy storage element in the first direction; and a second projection protruding to the one side in the first direction, the second projection being inserted into the first insertion portion.

2. The first projection and the first insertion portion have a tapered shape, with the width in the direction intersecting the first direction decreasing as they advance toward one side of the first direction, and the second projection has the tapered shape corresponding to the first insertion portion, as described in claim 1.

3. In the first direction, the tip of the second projection is located on one side of the first direction relative to the first tray body, as described in claim 1 or 2.

4. The energy storage device according to claim 1 or 2, wherein the energy storage element comprises a container for housing an electrode body, and when viewed from the first direction, the first protrusion, the first insertion portion, and the second protrusion extend along the outer edge of the container.

5. The energy storage device according to claim 4, wherein, when viewed from the first direction, the outer edge of the container is rectangular, and when viewed from the first direction, the first projection, the first insertion portion, and the second projection extend along at least three of the four sides forming the outer edge.

6. The energy storage device according to claim 1 or 2, wherein the first projection protrudes in a direction intersecting the first direction and includes a first convex portion extending in the first direction, the first insertion portion is a first recess formed inside the first convex portion and includes a first recess extending in the first direction, the second projection portion includes a second convex portion extending in the first direction, and the second convex portion is inserted into the first recess.

7. The energy storage device according to claim 1 or 2, further comprising: a pair of end members that sandwich the first tray, the second tray, and the energy storage unit including the energy storage element in the first direction; and a flexible wire connecting the pair of end members.

8. The energy storage device according to claim 7, wherein the first tray comprises a first guide portion having a first guide hole through which the wire passes, and the second tray comprises a second guide portion having a second guide hole through which the wire passes.

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