Power storage device and vehicle

Abstract

To provide a power storage device and a vehicle that are easier to manufacture while suppressing an increase in the size or number of parts.SOLUTION: A power storage device 100 includes a first case (case 301) that houses a first cell group (cell group GA) and a second case (case 302) that houses a second cell group (cell group GB). Each of the first cell group and the second cell group includes a plurality of power storage cells (power storage cells 11 to 14, power storage cells 21 to 24, power storage cells 31 to 34, and power storage cells 41 to 44) that are connected in a first direction (X direction). The first case has an opening at one end in a second direction (Y direction) that is perpendicular to the first direction. The first case and the second case are arranged such that the second case covers the opening of the first case.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a power storage device including a plurality of power storage cells and a vehicle. [Background technology]

[0002] JP 2023-502457 A (Patent Document 1) discloses a rectangular parallelepiped battery (electricity storage device) having a length L of 400 mm to 2500 mm and a ratio of length L to width H (L / H) of 4 to 21. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2023-502457 Summary of the Invention [Problem to be solved by the invention]

[0004] In the power storage device described in Patent Document 1, a plurality of electrode sets (power storage cells) connected in series and arranged in a row are disposed in a case (housing). Such a power storage device includes a collection (cell group) of a plurality of electrically connected power storage cells.

[0005] In manufacturing the above-mentioned energy storage device, it is necessary to place the cell group in a case. For example, it is conceivable to place the cell group in the case through an opening provided in the case, then close the opening with a lid and join the case body and the lid. However, if the opening of the case is made small, it becomes difficult to place the cell group in the case. Conversely, if the opening of the case is made large, a large lid (or many lids) is required to close the opening. Increasing the size or number of parts can make it difficult to manufacture the energy storage device and can lead to higher manufacturing costs.

[0006] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide an electricity storage device and a vehicle that are easier to manufacture while suppressing an increase in the size or number of parts. [Means for solving the problem]

[0007] According to one embodiment of the present disclosure, there is provided a power storage device as described below.

[0008] (Item 1) The energy storage device includes a first case that houses a first cell group and a second case that houses a second cell group. Each of the first cell group and the second cell group includes a plurality of energy storage cells connected in a first direction. The first case has an opening at one end in a second direction that is perpendicular to the first direction. The first case and the second case are arranged so that the second case covers the opening of the first case.

[0009] In the above configuration, the opening of the first case that houses the first cell group is blocked by the second case that houses another cell group (the second cell group), so there is no need to prepare a separate lid material to block the opening of the first case. This prevents an increase in the number of parts. At least one surface of the second case is formed large enough to house the second cell group. Therefore, even if the first case has an opening large enough to easily pass through for the first cell group, the opening of the first case can be blocked by the second case. The above configuration makes it possible to provide an energy storage device in which it is easy to place the cell group in the case, i.e., an energy storage device that is easy to manufacture.

[0010] (Item 2) In the energy storage device described in item 1, each of the first case and the second case has a rectangular parallelepiped shape with an opening formed at one end in the second direction. Each of the first case and the second case has a first surface and a second surface located at both ends in the first direction, and a third surface, a fourth surface, and a fifth surface extending in the first direction. The third surface is located on the opposite side of the opening in the second direction. The opening of the first case has an area larger than each of the first surface and the second surface of the first case. The third surface of the second case closes the opening of the first case.

[0011] In the above configuration, the first case has an opening formed therein having a larger area (opening area) than the two end faces (first surface, second surface) in the first direction. By forming an opening in the first case that is larger than the opening formed in either end face of the first case, it becomes easier to insert the first cell group into the first case through the opening. Furthermore, a rectangular parallelepiped case has a simple shape and is therefore easy to manufacture. As described above, the fact that the first case and the second case have the same or similar shapes also contributes to reducing manufacturing costs. According to the above configuration, it becomes easier to manufacture the energy storage device, and manufacturing costs tend to be reduced.

[0012] (Item 3) In the energy storage device described in item 2, the first case and the second case are joined together so that the first case is sealed when the first cell group is housed in the first case. The energy storage device further includes a lid that closes the opening of the second case so that the second case is sealed when the second cell group is housed in the second case.

[0013] According to the above configuration, each case can be sealed with the cell group housed therein.

[0014] (Item 4) The electricity storage device according to any one of items 1 to 3, further comprising a mechanism that generates a force that presses the second case against the first case.

[0015] According to the above configuration, it is possible to reduce (or eliminate) the gap between the opening of the first case that houses the first cell group and the second case.

[0016] According to an embodiment of the second aspect of the present disclosure, there is provided a vehicle as follows.

[0017] (Item 5) The vehicle includes the power storage device according to any one of Items 1 to 4.

[0018] The vehicle includes a power storage device that has a configuration that prevents an increase in the size or number of parts and is easy to manufacture. [Effects of the Invention]

[0019] According to the present disclosure, it is possible to provide a power storage device and a vehicle that are easier to manufacture while suppressing an increase in the size or number of parts. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a diagram illustrating a configuration of a power storage device according to an embodiment of the present disclosure. [Figure 2] 2 is a diagram for explaining the configuration of each cell connected body shown in FIG. 1. FIG. [Figure 3] FIG. 2 is a cross-sectional view taken along line III-III in FIG. [Figure 4] 10A to 10C are diagrams for explaining the functions and effects achieved by the power storage device according to the embodiment of the present disclosure. [Figure 5] FIG. 2 is a diagram showing a first modified example of the power storage device shown in FIG. [Figure 6] 1. FIG. 5 is a diagram showing a second modified example of the power storage device shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0021] Embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, identical or corresponding parts are designated by the same reference numerals, and their description will not be repeated. In each of the drawings used below, of the mutually orthogonal X-, Y-, and Z-axes, the X-axis indicates a first in-plane direction (e.g., the length direction) of the power storage device, the Y-axis indicates a second in-plane direction (e.g., the width direction) of the power storage device, and the Z-axis indicates a height direction of the power storage device. Hereinafter, the directions indicated by the arrows of the X-, Y-, and Z-axes will be indicated with a "+" and the opposite directions will be indicated with a "-".

[0022] FIG. 1 is a diagram illustrating the configuration of a power storage device according to this embodiment. The power storage device 100 according to this embodiment is configured to store electricity. As will be described in detail later, the power storage device 100 includes a plurality of storage cells, each of which functions as a secondary battery. Examples of secondary batteries include lithium-ion batteries, nickel-metal hydride batteries, and sodium-ion batteries. Examples of lithium-ion batteries include LFP batteries that use lithium iron phosphate as the positive electrode active material, and ternary batteries that use NMC (nickel-manganese-cobalt) as the positive electrode active material. The type of secondary battery may be a liquid secondary battery or an all-solid-state secondary battery. The power storage device 100 may include only storage cells of the same type (e.g., only LFP batteries) or may include storage cells of different types (e.g., LFP batteries and ternary batteries).

[0023] The left side of Fig. 1 shows the inside of the case as seen from the +Z side. A A case 301 (first case) that houses the cell group G (first cell group) B The battery includes a case 302 (second case) that houses a battery cell group (second cell group), and a case 303 that houses a biasing device 50. Each of the cases 301 to 303 has a rectangular parallelepiped shape with an opening formed on the +Y side. The corners of each of the cases 301 to 303 may be chamfered (for example, rounded). The X direction corresponds to the longitudinal direction of each of the cases 301 to 303. In this embodiment, the X direction and the Y direction correspond to examples of the "first direction" and "second direction" according to the present disclosure, respectively.

[0024] The materials constituting each of the cases 301 to 303 can be, for example, metal. Each of the cases 301 to 303 is made of, for example, aluminum. However, the present invention is not limited to this, and each of the cases 301 to 303 may be made of resin. Also, different materials may be used for different parts of the case (for example, faces F1 to F5, which will be described later). In this embodiment, the cases 301, 302, and 303 have the same dimensions and shape. Therefore, the following description will focus on the dimensions and shape of only the case 301 as a representative example.

[0025] The case 301 has faces F1 and F2 located at both ends in the X direction, and faces F3 to F5 extending in the X direction. The face F1 (first face) faces the cell group G accommodated in the case 301. A The surface F2 (second surface) covers the end of the +X side of the cell group G housed in the case 301. A The case 301 covers the end on the -X side of the case 301. The case 301 has a face F3 (third face) at one end in the Y direction (-Y side) and an opening at the other end in the Y direction (+Y side). The face F3 is located on the opposite side of the opening in the Y direction. In this embodiment, the opening is formed over the entire surface of the face opposite to the face F3, but the opening may be formed partially. The face F4 (fourth face) and the face F5 (fifth face) correspond to a pair of opposing faces facing each other in the Z direction. Each of the faces F1 to F5 corresponds to a plate-like portion that constitutes the case 301. However, the shape of each of the cases 301 to 303 is not limited to the above.

[0026] The opening and the surface F3 on the opposite side thereof each have a larger area than the surfaces F1 and F2. The length (dimension in the X direction) of the case 301 is longer than the width (dimension in the Y direction) of the case 301. The length of the case 301 may be 250 mm or more and 5000 mm or less, for example, approximately 1000 mm. The width of the case 301 may be 10 mm or more and 1250 mm or less, for example, approximately 50 mm. The ratio of the length of the case 301 to the width of the case 301 may be 4 or more and 25 or less. The height (dimension in the Z direction) of the case 301 may be 10 mm or more and 1250 mm or less, for example, approximately 100 mm. However, the dimensions of each of the cases 301 to 303 are not limited to those described above.

[0027] In the energy storage device 100, as shown in Fig. 1, the face F3 of the case 302 closes the opening of the case 301. A The case 301 and the case 302 are joined together so that the case 301 is sealed with the cell group G housed therein. The surface F3 of the case 303 closes the opening of the case 302. The case 302 is BCase 302 and case 303 are joined together so as to be sealed with the container housed therein. Case 303 functions as a lid that closes the opening of case 302.

[0028] The biasing device 50 housed in the case 303 includes a mechanism that generates a force (a load toward the -Y side) that presses the surface F3 of the case 303 against the case 302. The transmission of this force (load) further presses the surface F3 of the case 302 against the case 301. The biasing device 50 may generate a biasing force and use the biasing force to apply force to the case 302. The biasing device 50 may include a mechanism that mechanically generates the biasing force (for example, a mechanism that uses a spring). The biasing device 50 may also include a mechanism that generates the biasing force using electricity (for example, a mechanism that uses an electric actuator). Pressing the surface F3 (plate-shaped portion) of the case 303 against the case 302 makes it possible to reduce (or eliminate) the gap between the opening of the case 302 and the surface F3 of the case 303. Furthermore, by pressing face F3 (plate-shaped portion) of case 302 against case 301, it is possible to reduce (or eliminate) the gap between the opening of case 301 and face F3 of case 302. In this way, the openings of cases 301 and 302 are blocked by the other case (case 302 or 303), thereby improving the airtightness of cases 301 and 302. An elastic body and / or adhesive may be provided between case 301 and case 302 and between case 302 and case 303 so that the surface pressure due to the above-mentioned force (load) is applied uniformly to cases 301 and 302.

[0029] In the power storage device 100, cases 301 to 303 (three housings each having an opening on the +Y side) are stacked in the Y direction. This improves the volumetric efficiency of the power storage device 100. Furthermore, of the cases 301 to 303, the opening of case 303, which is located furthest on the +Y side, is not blocked but remains open. This improves the heat dissipation performance of the housing portion of case 303 (including biasing device 50). However, the present invention is not limited to this structure, and the opening of case 303 may be blocked by a lid (not shown).

[0030] Each face F1 of the cases 301 and 302 is provided with components for managing the housed cell group. Because the faces F1 of the cases 301 and 302 have the same structure, the right side of FIG. 1 shows an enlarged view of the face F1 of the case 301 as a representative example. Each face F1 of the cases 301 and 302 is provided with a sealing hole 310, an external terminal 320, and a connector 330. The sealing hole 310 may be a pressure adjustment hole for adjusting the pressure inside the case. The sealing hole 310 has a sealing structure, for example, with a metal cap (outside the case) and a sealing member (inside the case). This sealing structure ensures airtightness inside the case, and when the pressure inside the case exceeds a predetermined level, gas is discharged to the outside of the case through the sealing hole 310. The external terminal 320 includes an electrode tab 321 joined (e.g., laser welded) to a first connection terminal of the cell group and an electrode tab 322 joined (e.g., laser welded) to a second connection terminal of the cell group. For example, in the external terminal 320 provided on the face F1 of the case 301, the electrode tab 321 is connected to the cell group G. A The electrode tab 322 is joined to the connection terminal T1 of the cell group G A In addition, the external terminal 320 provided on the surface F1 of the case 302 has an electrode tab 321 connected to the connection terminal T2 of the cell group G. B The electrode tab 322 is joined to the connection terminal T3 of the cell group G. BThe electrode tabs 321, 322 are joined to the connection terminal T4 of the case. Each of the electrode tabs 321, 322 may have, for example, a ceramic insulating seal structure around the electrode. In this embodiment, the electrode tabs 321, 322 function as a negative electrode tab and a positive electrode tab, respectively. However, this is not limited to this, and the polarities may be reversed, with the electrode tab 322 serving as a negative electrode tab and the electrode tab 321 serving as a positive electrode tab. The connector 330 includes, for example, an output terminal that outputs a detection signal indicating a state inside the case (e.g., the temperature of each storage cell) detected by one or more sensors inside the case to the outside of the case, and an input terminal that inputs a control signal from the outside of the case to one or more devices inside the case. For example, a temperature sensor may be provided for each storage cell inside the case. Note that the structure of the face F1 of each case is not limited to the above and can be modified as appropriate. For example, a vacuum pressure adjustment valve may be provided in the sealing hole 310 of each of the cases 301, 302 to create a vacuum inside the cases 301 and 302. Furthermore, at least one of a pressure adjustment hole and a gas exhaust valve may be provided on the surface F2 of each of the cases 301 and 302.

[0031] Cell group G A and cell group G B Each of the cell groups G includes a plurality of storage cells connected in the X direction. A The cell group G includes an electrically connected cell string 10 (first cell string) and a cell string 20 (second cell string). B includes an electrically connected connected cell body 30 (first connected cell body) and a connected cell body 40 (second connected cell body). Each of the power storage cells included in these connected cell bodies is configured to be able to store power.

[0032] The cell assembly 10 includes four storage cells 11 to 14 arranged in the X direction and three connection parts 2 that electrically connect the storage cells. The storage cells 11 to 14 are connected in a row in the X direction inside the case 301. The cell assembly 20 includes four storage cells 21 to 24 arranged in the X direction and three connection parts 2 that electrically connect the storage cells. The storage cells 21 to 24 are connected in a row in the X direction inside the case 301. In this manner, the cell assembly 10 and the cell assembly 20 are arranged parallel to the X direction. In this embodiment, the cell assembly 10 and the cell assembly 20 are arranged such that the positions of the storage cells and the connection parts are aligned. A connection terminal T1 is provided at the end (storage cell 11) on the +X side of the cell assembly 10, and a connection terminal T2 is provided at the end (storage cell 21) on the +X side of the cell assembly 20. The energy storage cells 11 and 21 are electrically connected to electrode tabs 321 and 322 (surface F1) of the case 301 via connection terminals T1 and T2, respectively. The -X side end (energy storage cell 14) of the connected cell body 10 and the -X side end (energy storage cell 24) of the connected cell body 20 are electrically connected within the case 301 via, for example, a U-shaped connection part 3.

[0033] The cell assembly 30 includes four storage cells 31 to 34 arranged in the X direction and three connection parts 2 that electrically connect the storage cells. The storage cells 31 to 34 are connected in a row in the X direction inside the case 302. The cell assembly 40 includes four storage cells 41 to 44 arranged in the X direction and three connection parts 2 that electrically connect the storage cells. The storage cells 41 to 44 are connected in a row in the X direction inside the case 302. In this manner, the cell assembly 30 and the cell assembly 40 are arranged parallel to the X direction. In this embodiment, the cell assembly 30 and the cell assembly 40 are arranged such that the positions of the storage cells and the connection parts are aligned. A connection terminal T3 is provided at the end (storage cell 31) on the +X side of the cell assembly 30, and a connection terminal T4 is provided at the end (storage cell 41) on the +X side of the cell assembly 40. The energy storage cells 31 and 41 are electrically connected to electrode tabs 321 and 322 (surface F1) of the case 302 via connection terminals T3 and T4, respectively. The -X side end (energy storage cell 34) of the cell connected body 30 and the -X side end (energy storage cell 44) of the cell connected body 40 are electrically connected within the case 302 via, for example, a U-shaped connection part 3.

[0034] Cell group G A and G B The connecting portion 3 in each of these may be an integrally molded product, or may be a composite of a plurality of separately molded parts. For example, the connecting portion 3 may be formed by connecting a protruding portion 144B (FIG. 2) protruding from the power storage cell 14 or 34 with a protruding portion 144B (FIG. 2) protruding from the power storage cell 24 or 44 via a conductive material (beam portion). The protruding portion 144B will be described later.

[0035] In this embodiment, the cell connected bodies 10, 20, 30, and 40 basically have the same configuration. Hereinafter, when there is no need to distinguish between the power storage cells 11 to 14, 21 to 24, 31 to 34, and 41 to 44, they will be referred to as "power storage cells 1."

[0036] FIG. 2 is a diagram illustrating the configuration of each connected cell body. As shown in FIG. 2, each connected cell body includes four energy storage cells 1. Connection portions 2 are provided between adjacent energy storage cells 1, and the connection portions 2 electrically connect the energy storage cells 1. Each connected cell body is configured such that the energy storage cells 1 and the connection portions 2 are arranged alternately. In each connected cell body, the energy storage cells 1 are connected to each other via the connection portions 2. The rigidity of the connection portions 2 is lower than the rigidity of the energy storage cells 1. Energy storage cells 11 to 14, 21 to 24, 31 to 34, and 41 to 44 are configured from the same energy storage cells 1. By forming the connected cell bodies 10, 20, 30, and 40 using common energy storage cells 1, the energy storage device 100 can be manufactured more easily and manufacturing costs can be reduced.

[0037] In this embodiment, the energy storage cell 1 is a laminate cell having one or more wound bodies. In a laminate cell, one or more wound bodies functioning as electrode bodies are covered with a laminate outer casing. The wound body has a structure in which, for example, a positive electrode sheet and a negative electrode sheet are wound with a separator interposed therebetween. Each of the positive electrode sheet and the negative electrode sheet includes an electrode foil and an active material layer.

[0038] 2 (an XY cross-sectional view of the periphery of the connection portion 2), the structures of the energy storage cell 1 and the connection portion 2 will be described below. The energy storage cell 1 includes two wound bodies 110A and 110B, spacers 120A and 120B, terminal members 130A and 130B, and covers 150A and 150B.

[0039] The wound bodies 110A and 110B have coated portions 111A and 111B, electrode tabs 112A and 112B, and electrode tabs 113A and 113B, respectively. Each of the coated portions 111A and 111B is a region of the electrode foil on the positive electrode sheet or the negative electrode sheet where an active material layer is provided. Each of the electrode tabs 112A, 112B, 113A, and 113B is a region of the positive electrode sheet or the negative electrode sheet where the electrode foil is exposed (an uncoated portion where no active material layer is provided). The electrode tabs 112A and 112B are located at the +X side ends of the wound bodies 110A and 110B, respectively. The electrode tabs 113A and 113B are located at the −X side ends of the wound bodies 110A and 110B, respectively.

[0040] The electrode tabs 112A and 112B are arranged to overlap in the Y direction, and a spacer 120A and a terminal member 130A are provided between the electrode tabs 112A and 112B. The electrode tabs 113A and 113B are arranged to overlap in the Y direction, and a spacer 120B and a terminal member 130B are provided between the electrode tabs 113A and 113B.

[0041] Each of the spacers 120A, 120B contains an insulating material (e.g., synthetic resin) and is insulating. Each of the spacers 120A, 120B has a shape in which the dimension in the Y direction increases with increasing distance from the coated portions 111A, 111B. The terminal member 130A is connected to an end face on the +X side of the spacer 120A. The terminal member 130B is connected to an end face on the -X side of the spacer 120B. Each of the terminal members 130A, 130B contains a conductive material (e.g., a metal such as aluminum or copper) and is conductive. The wound body 110A and the wound body 110B are joined (e.g., laser welded) to each other via the terminal members 130A and 130B.

[0042] Each of the current collecting terminals 140A, 140B is a component that constitutes a part of the connection portion 2. The current collecting terminals 140A, 140B have support portions 142A, 142B and protrusions 144A, 144B, respectively. One of the current collecting terminals 140A and 140B functions as a positive electrode current collecting terminal, and the other functions as a negative electrode current collecting terminal. In one example, the positive electrode current collecting terminal is made of aluminum, and the negative electrode current collecting terminal is made of copper.

[0043] Each of the current collecting terminals 140A, 140B is formed in an L-shape and may be formed by joining two separately formed plate materials, or may be formed into an integrated state by bending. The support portion 142A is joined (for example, by laser welding) to the end surface on the +X side of the terminal member 130A. The support portion 142B is joined (for example, by laser welding) to the end surface on the -X side of the terminal member 130B.

[0044] The cover 150A covers the end portion of the energy storage cell 1 on the +X side (including the electrode tabs 112A and 112B). However, the cover 150A has a through hole h1 for the protrusion 144A. The protrusion 144A passes through the through hole h1 and protrudes toward the +X side of the energy storage cell 1. The cover 150B covers the end portion of the energy storage cell 1 on the -X side (including the electrode tabs 113A and 113B). However, the cover 150B has a through hole h2 for the protrusion 144B. The protrusion 144B passes through the through hole h2 and protrudes toward the -X side of the energy storage cell 1.

[0045] At the connection portion 2, of two adjacent energy storage cells 1, a protruding portion 144A protruding from one energy storage cell 1 is joined (for example, by laser welding) to a protruding portion 144B protruding from the other energy storage cell 1. The welded portion may be protected with tape or the like. Furthermore, a laminated outer casing 160 is provided on the surfaces of the two wound bodies 110A and 110B. The laminated outer casing 160 is, for example, a laminated film, and is provided on the surfaces of the energy storage cells 1.

[0046] 3 is a cross-sectional view taken along line III-III in FIG. 1. Each of the cases 301 to 303 shown in FIG. 1 has a U-shaped cross-section as shown in FIG. 3, which is a cross-section perpendicular to the X direction (YZ cross-section). In each of the cases 301 and 302, a region R exists between the +Z side surface of each storage cell and the inner surface (top surface) of the case. The region R may be provided with at least one of a thermal management system (e.g., a heater and / or a temperature sensor), a gas exhaust system (e.g., a gas flow path and / or a pressure sensor), an FPC (flexible printed circuit board), and wiring connected to the connector 330. The devices and / or sensors provided in the region R may be connected to the connector 330. The storage cells housed in the cases 301 and 302 may be adhered to the inner surface of the case with an adhesive.

[0047] The above-described configuration is merely one example of the configuration of the energy storage cell 1 and can be modified as appropriate. For example, the number of wound bodies included in the energy storage cell 1 is not limited to two, and may be one, three, or more. Furthermore, a laminate (for example, a laminate in which a positive electrode sheet and a negative electrode sheet are laminated with a separator interposed therebetween) may be used as the electrode body instead of the wound body. Furthermore, an insulating layer containing a resin such as PET (polyethylene terephthalate) may be provided on the inner surface of each case.

[0048] FIG. 4 is a diagram for explaining the action and effect achieved by the energy storage device 100. In a configuration in which electrically connected cell connected bodies 10 and 20 are housed in a bottomed cylindrical case 400 having an opening on the end face on the +X side, as in the reference example in FIG. 4, a problem may arise in that it is difficult to insert the cell connected bodies 10 and 20 into the case 400. Furthermore, in this reference example, in order to seal the inside of the case 400, a lid material for closing the opening of the case 400 is required. In contrast, in the energy storage device 100 shown in FIGS. 1 to 3, the cell group G A The opening of the case 301 that houses the cells is connected to another cell group (cell group G BSince the opening of the case 301 is closed by the case 302 that houses the cell group G, there is no need to prepare a separate cover material to close the opening of the case 301. This prevents an increase in the number of parts. A The case 301 has an opening of a size that allows the passage of the cell group G easily (specifically, the same size as the surface F3 on the opposite side). A Since the case 302 has the same shape and dimensions as the case 301, the opening of the case 301 can be closed by the face F3 of the case 302. Furthermore, the case 302 can easily accommodate the cell group G. B The case 302 has an opening of a size that allows the passage of the cell group G easily (specifically, the same size as the surface F3 on the opposite side). B This makes it easier to insert the case 302. Furthermore, since the case 303 has the same shape and dimensions as the case 302, the opening of the case 302 can be closed by the surface F3 of the case 303.

[0049] The number of cases that house the cell group is not limited to 2, but may be 3 or more. FIG.

[0050] As shown in Fig. 5, the energy storage device 100A according to the first modification includes N cases (cases 300-1, 300-2, ..., 300-N) and N cell groups (cell groups G-1, G-2, ..., GN). Specifically, the energy storage device 100A includes cases 300-1 to 300-N and cell groups G-1 to GN housed in the cases 300-1 to 300-N, respectively. Each of the cell groups G-1 to GN is the same as the cell group G described above. A (See FIGS. 1 to 3.) N may be 3 or more and less than 20, or may be 20 or more.

[0051] Each of the cases 300-1 to 300-N has the same shape as the above-described case 301 (see FIG. 4). The cases 300-1 to 300-N are stacked in the Y direction as shown in FIG. 5. The power storage device 100A further includes a restraining device that restrains these cases (stacked body) in the Y direction. The restraining device includes pressure plates 501 and 502, connecting shafts 503 and 504, and bolts P1 to P4. The pressure plate 501 is connected to the connecting shafts 503 and 504 by bolts P1 and P2, respectively. The pressure plate 502 is connected to the connecting shafts 503 and 504 by bolts P3 and P4, respectively. By tightening the bolts P1 to P4, pressure (restraining force) is applied to the stacked body (cases 300-1 to 300-N) in the Y direction. The restraining pressure may be increased by creating a vacuum inside each case.

[0052] The openings of each of cases 300-1 to 300-N are closed. The opening of case 300-N located furthest on the +Y side among cases 300-1 to 300-N is closed by pressure plate 501 (e.g., a flat plate), and the openings of the other cases are closed by the case located adjacent (on the +Y side). Pressure plate 501 functions as a lid that closes the opening of case 300-N. The airtightness of each case may be improved by applying a restraining force to the stack (cases 300-1 to 300-N) so that pressure plate 501 crushes case 300-N. An elastic body and / or adhesive may be provided between case 300-N and pressure plate 501 so that the surface pressure from the restraining device is applied uniformly to case 300-N. Each case may be restrained by a band (e.g., a rubber band) instead of a bolt (fastening).

[0053] The number of cell coupled bodies housed in the case is not limited to two and is arbitrary. The number of cell coupled bodies housed in the case may be three or more, or may be one. Figure 6 is a diagram showing a second modified example of the energy storage device 100.

[0054] As shown in FIG. 6, the power storage device 100B according to the second modification includes a cell group G C A case 301A (first case) that houses the cell group G (first cell group) Dand a case 302A (second case) that houses the cell group G (second cell group). C ,G D Each of these is a single cell combination having the configuration shown in FIG.

[0055] Each of the cases 301A and 302A basically has the same shape as the case 301 described above (see FIG. 4). However, in the case 301A, an electrode tab 321A is provided on the surface F1, and an electrode tab 322A is provided on the surface F2. The energy storage cell 1 located at one end in the X direction (+X side) of the cell assembly housed in the case 301A has a connection terminal T1A electrically connected to the electrode tab 321A. The energy storage cell 1 located at the other end in the X direction (-X side) of the cell assembly housed in the case 301A has a connection terminal T2A electrically connected to the electrode tab 322A. In the case 302A, an electrode tab 321B is provided on the surface F1, and an electrode tab 322B is provided on the surface F2. The energy storage cell 1 located at one end in the X direction (+X side) of the cell assembly housed in the case 302A has a connection terminal T1B electrically connected to the electrode tab 321B. The energy storage cell 1 located at the other end in the X direction (-X side) of the cell assembly housed in the case 302A has a connection terminal T2B electrically connected to the electrode tab 322B.

[0056] In the power storage device 100B, the surface F3 of the case 302A closes the opening of the case 301A. C In addition, a cover may be provided on the +Y side of the case 302A, and the opening of the case 302A may be closed with the cover. D are surrounded and protected by the case 302A and the lid. The lid may be a separate case that houses the cell group, or may be a flat lid.

[0057] The configuration of each cell group is not limited to the configuration shown in Fig. 2. Each cell group may include energy storage cells of different sizes or different shapes. The number of energy storage cells included in each cell group may be less than four, 5 to 19, or 20 or more.

[0058] It is not essential that all the cases housing the cell group have the same shape. It is also not essential that all the cases housing the cell group be sealed. For example, by removing the case 303 and the biasing device 50 from the power storage device 100 shown in FIG. 1, the case 302 can be used to house the cell group G. B The case 302 may be opened with the cell group G housed therein. B The heat dissipation performance of the device can be improved.

[0059] The above-described power storage devices 100, 100A, and 100B may be mounted on, for example, a mobile object. Examples of mobile objects include automobiles (electric vehicles, hybrid vehicles, etc.), vehicles other than automobiles (ships, airplanes, etc.), mobile machines (agricultural machines, construction machines, etc.), and unmanned mobile objects (automated guided vehicles, robots, etc.). However, the power storage devices may be used for any purpose, and may be stationary.

[0060] The various features of the power storage device described above (the features described in the embodiments and modifications) may be implemented in any combination.

[0061] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0062] 1, 11 to 14, 21 to 24, 31 to 34, 41 to 44 storage cells, 2 connection part, 3 connection part, 10, 20, 30, 40 cell connecting body, 50 energizing device, 100, 100A, 100B storage device, 300-1 to 300-N, 301 to 303, 301A, 302A case, 501, 502 pressure plate, G A ,G B ,G C ,G D ,G-1~GN cell groups.

Claims

1. An electricity storage device, The power storage device is a first case that houses the first cell group; a second case that houses the second cell group; Equipped with each of the first cell group and the second cell group includes a plurality of power storage cells connected in a first direction; the first case has an opening at one end in a second direction perpendicular to the first direction, The first case and the second case are arranged such that the second case covers the opening of the first case.

2. each of the first case and the second case has a rectangular parallelepiped shape with an opening formed at one end in the second direction; each of the first case and the second case has a first surface and a second surface located at opposite ends in the first direction, and a third surface, a fourth surface, and a fifth surface extending in the first direction; the third surface is located on the opposite side of the opening in the second direction, the opening of the first case has an area larger than each of the first surface and the second surface of the first case, The power storage device according to claim 1 , wherein the third surface of the second case covers the opening of the first case.

3. the first case and the second case are joined together so that the first case is sealed while accommodating the first cell group, The power storage device according to claim 2 , further comprising a lid member that closes the opening of the second case so that the second case is sealed while accommodating the second cell group.

4. 4. The power storage device according to claim 1, further comprising a mechanism that generates a force that presses said second case against said first case.

5. A vehicle comprising the power storage device according to any one of claims 1 to 3.

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