Power storage device

Abstract

To facilitate the manufacture of a power storage device having a case for housing a cell connection.SOLUTION: A power storage device (battery 100) comprises a case 300. The case 300 includes a hinge section 330 for opening and closing the case 300. The case 300 houses the cell connections (cell connections 10, 20). The cell connection comprises a plurality of power storage cells (power storage cells 11 to 14 in the cell connection 10, power storage cells 21 to 24 in the cell connection 20) and connection sections (connection sections 2 between adjacent power storage cells in the cell connection 10 or 20) that electrically connect the power storage cells to each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an energy storage device including a plurality of energy storage cells. [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 energy storage device described in Patent Document 1, a plurality of electrode assembly sets (energy storage cells) connected in series and arranged in a row are disposed in a case (housing). Hereinafter, a series of a plurality of energy storage cells connected in a row will be referred to as a "cell series."

[0005] In manufacturing the above-described energy storage device, it is necessary to place the cell assembly into a case. For example, it is conceivable to place the cell assembly into the case body through an opening provided in the case body, then close the opening of the case body with a lid and join the case body and the lid. In such an energy storage device, the case body and the lid are prepared separately. Therefore, there is a concern that a lid that does not fit the case body may be prepared, or that the case body and the lid may be joined in a misaligned state.

[0006] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to facilitate the manufacture of an electricity storage device that includes a case that houses a cell assembly. [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 case. The case includes a hinge portion that opens and closes the case. The case houses a cell assembly. The cell assembly includes a plurality of energy storage cells and connection portions that electrically connect the energy storage cells to each other.

[0009] In the above configuration, the case includes a hinge portion. Therefore, after the cell assembly is inserted into the case with the case open by the hinge portion, the case can be closed by the hinge portion. Since the case can be opened and closed by the hinge portion during the manufacturing process of the energy storage device, manufacturing of the energy storage device becomes easier. Note that the hinge portion only needs to function at least during the manufacturing process of the energy storage device, and the case may be fixed in a closed state in the finished product.

[0010] (Item 2) In the energy storage device described in item 1, the case has a rectangular parallelepiped shape. The plurality of energy storage cells are connected in a first direction. The case has a first surface, a second surface, a third surface, and a fourth surface extending in the first direction, and a fifth surface and a sixth surface located at both ends of the first direction. The first surface and the second surface face each other in a second direction perpendicular to the first direction. The third surface and the fourth surface face each other in a third direction perpendicular to each of the first direction and the second direction. The second surface includes a hinge portion. The case includes a first case member and a second case member connected via the hinge portion. The first surface includes a joining portion where the first case member and the second case member are joined.

[0011] The rectangular parallelepiped case extends in the same direction as the cell assembly (plurality of energy storage cells), making it easy to properly accommodate the cell assembly. During the manufacturing process of the energy storage device, the case can be opened and closed using the hinge portion. Furthermore, the first case member and the second case member are joined at the surface (first surface) opposite the hinge portion (second surface). This makes it easy to maintain the case in a closed state. Furthermore, the rectangular parallelepiped case has a simple shape and is therefore easy to manufacture. The above configuration makes it easy to manufacture the energy storage device and tends to reduce manufacturing costs.

[0012] (Item 3) In the electricity storage device described in item 2, the hinge portion is a portion formed with a thin plate thickness on the second surface, and is formed along the first direction.

[0013] As described above, by partially thinning the plate thickness of the second surface, a hinge portion with a simple configuration can be formed. The above configuration makes it easier to form the hinge portion. Furthermore, by forming the hinge portion along the first direction, it becomes easier to form a large opening when the case is opened by the hinge portion. This makes it easier to insert the cell assembly into the case.

[0014] The thickness of the second surface may be thinner than the thickness of the first surface. By making the thickness of the second surface thinner, deformation of the second surface including the hinge portion is promoted. Furthermore, by making the thickness of the first surface thicker, the strength of the first surface including the joint portion is increased.

[0015] (Item 4) In the electricity storage device according to item 2 or 3, the connecting portion has a snap-fit ​​structure.

[0016] In the above-described power storage device, the mechanical connection based on the snap-fit ​​structure makes it easy to keep the case closed.

[0017] (Item 5) In the electricity storage device according to any one of items 1 to 4, the case is made of resin.

[0018] The resin case has insulating properties, so the above configuration eliminates the need for components to electrically insulate the case from the components inside the case, thereby preventing an increase in the number of components.

[0019] In another embodiment, a vehicle including the power storage device according to any one of paragraphs 1 to 5 may be provided. [Effects of the Invention]

[0020] According to the present disclosure, it is easy to manufacture an electricity storage device that includes a case that houses a cell connected body. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a diagram illustrating a configuration of a power storage device according to an embodiment of the present disclosure. [Figure 2] 2A to 2C are diagrams illustrating a function of a hinge portion in a manufacturing process of the power storage device shown in FIG. [Figure 3] 2 is a diagram for explaining the configuration of each cell connected body shown in FIG. 1. FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Figure 5] 2 is a diagram for explaining the operation and effect achieved by the power storage device shown in FIG. 1. FIG. [Figure 6] 1. FIG. 3 is a diagram showing first to third modified examples of the case shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0022] 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-axis, Y-axis, and Z-axis, the X-axis indicates a first in-plane direction of the battery (e.g., the length direction), the Y-axis indicates a second in-plane direction of the battery (e.g., the width direction), and the Z-axis indicates the height direction of the battery. Hereinafter, the directions indicated by the arrows of the X-axis, Y-axis, and Z-axis will be indicated with a "+" and the opposite directions will be indicated with a "-".

[0023] Fig. 1 is a diagram for explaining the configuration of the electricity storage device according to this embodiment. "Case internal configuration diagram-Z" in Fig. 1 is a diagram of the contents of the case as seen from the +Z side. "Case internal configuration diagram-Y" in Fig. 1 is a diagram of the contents of the case as seen from the +Y side.

[0024] The power storage device according to this embodiment is a battery 100 shown in FIG. 1. The battery 100 is a secondary battery such as a lithium-ion battery, a nickel-metal hydride battery, or a sodium-ion battery. Examples of lithium-ion batteries include an LFP battery that uses lithium iron phosphate as the positive electrode active material, or a ternary battery that uses NMC (nickel-manganese-cobalt) as the positive electrode active material. The secondary battery may be a liquid secondary battery or an all-solid-state secondary battery. As will be described in detail later, the battery 100 includes multiple storage cells that each function as a secondary battery. The battery 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., an LFP battery and a ternary battery).

[0025] The battery 100 includes a case 300. The case 300 has a rectangular parallelepiped shape with the X direction as its longitudinal direction. The case 300 has a pair of faces F1 and F2 (first opposing faces) opposing each other in the Z direction, a pair of faces F3 and F4 (second opposing faces) opposing each other in the Y direction, and faces F5 and F6 (X-direction end faces) located at both ends in the X direction. Each of the faces F1 to F4 extends in the X direction. The area of ​​each of the faces F1 and F2 is smaller than the area of ​​each of the faces F3 and F4. Each of the faces F1 to F6 corresponds to a plate-shaped portion that constitutes the case 300. The thickness of the face F1 is greater than the thicknesses of the other faces (faces F2 to F6). The thickness of the face F2 is less than the thicknesses of the other faces (faces F1, F3 to F6). In this embodiment, the X direction, Z direction, and Y direction correspond to examples of the "first direction," "second direction," and "third direction" according to the present disclosure, respectively. Furthermore, surfaces F1, F2, F3, F4, F5, and F6 correspond to examples of the "first surface," "second surface," "third surface," "fourth surface," "fifth surface," and "sixth surface," respectively.

[0026] The length of the case 300 (dimension in the X direction) is longer than the width of the case 300 (dimension in the Y direction). The length of the case 300 may be 250 mm or more and 5000 mm or less, for example, about 1000 mm. The width of the case 300 may be 10 mm or more and 1250 mm or less, for example, about 50 mm. The ratio of the length of the case 300 to the width of the case 300 may be 4 or more and 25 or less. The height of the case 300 (dimension in the Z direction) may be 10 mm or more and 1250 mm or less, for example, about 100 mm. However, the dimensions of the case 300 (including the plate thickness) are not limited to the above.

[0027] The surface F5 is provided with external terminals 311 and 321, a connector 313, and a sealing hole 323. The surface F6 is provided with external terminals 312 and 322. The external terminals 311 and 312 are joined (e.g., laser welded) to the connection terminals T11 and T12 of the cell assembly 10, respectively. The external terminals 321 and 322 are joined (e.g., laser welded) to the connection terminals T21 and T22 of the cell assembly 20, respectively. Each of the external terminals 311, 312, 321, and 322 may have a ceramic insulating seal structure around the electrode. In one example, each of the external terminals 311 and 322 functions as a negative electrode tab, and each of the external terminals 312 and 321 functions as a positive electrode tab. The external terminal 312 and the external terminal 322 may be connected via a conductive member (beam portion) to form a U-shaped connection. However, this is not limited to this, and the polarity can be set as desired. For example, the external terminals 311 and 321 may each be a negative electrode tab, and the external terminals 312 and 322 may each be a positive electrode tab.

[0028] Connector 313 includes, for example, an output terminal that outputs a detection signal indicating a state inside case 300 (e.g., the temperature of each energy storage cell) detected by one or more sensors inside case 300 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 case 300. For example, a temperature sensor may be provided for each energy storage cell inside case 300. Sealing hole 323 may be a pressure adjustment hole that adjusts the pressure inside case 300. Sealing hole 323 has a sealing structure that includes, for example, a metal cap (outside the case) and a sealing member (inside the case). This sealing structure ensures airtightness inside case 300, and when the pressure inside case 300 exceeds a predetermined level, gas is discharged to the outside of case 300 through sealing hole 323. At least one of a pressure adjustment hole and a gas discharge valve may be further provided on face F6.

[0029] The case 300 includes case members 310 and 320 and a hinge portion 330. The external terminals 311 and 312 and the connector 313 are provided on the case member 310 (first case member). The external terminals 321 and 322 and the sealing hole 323 are provided on the case member 320 (second case member). The hinge portion 330 is provided on the surface F2. The case members 310 and 320 are connected via the hinge portion 330. In this embodiment, resin is used as the material for each of the case members 310, 320, and the hinge portion 330. The case 300 is made of resin. Resin cases are more easily deformed and processed than metal cases. This makes it easier to manufacture a case 300 with the desired shape and dimensions. The case members 310 and 320 and the hinge portion 330 may be integrally molded. However, these materials can be changed as appropriate.

[0030] The hinge portion 330 is configured to open and close the case 300. Specifically, the hinge portion 330 is a portion formed with a thinner plate thickness on the surface F2. The plate thickness of the surface F2 is thinner than the plate thickness of the other surfaces (surfaces F1, F3 to F6), and in particular, the hinge portion 330 is thinner than the surrounding area. By partially reducing the plate thickness of the surface F2 in this manner, it is possible to form the hinge portion 330 with a simple configuration. The hinge portion 330 is formed linearly along the X direction over the entire area of ​​the case 300 in the X direction. The hinge portion 330 is located between the case member 310 and the case member 320 and is formed to connect the case member 310 and the case member 320. The hinge portion 330 supports the case members 310 and 320 while allowing the case members 310 and 320 to open and close. Therefore, the case members 310 and 320 can rotate around the hinge portion 330 (axis in the X direction) as the rotation axis. The case 300 is opened and closed by rotating one of the case members 310 and 320 relative to the other. However, it is sufficient that the hinge portion 330 functions at least during the manufacturing process of the battery 100, and the case 300 may be fixed in a closed state after the battery 100 is completed. FIG. 2 is a diagram for explaining the function of the hinge portion 330 during the manufacturing process of the battery 100. An example of a manufacturing method of the battery 100 will be described below with reference to FIG. 2.

[0031] First, the case 300 is opened by the hinge portion 330. Then, the cell assemblies 10 and 20 are placed inside the open case 300. Furthermore, each cell assemblies is joined to the corresponding external terminal.

[0032] Specifically, the cell assembly 10 is placed in a case member 310, and the connection terminals T11 and T12 of the cell assembly 10 are connected to external terminals 311 and 312, respectively. The cell assembly 20 is placed in a case member 320, and the connection terminals T21 and T22 of the cell assembly 20 are connected to external terminals 321 and 322, respectively. The "view from the -Y side" in FIG. 2 is a view from the -Y side showing the cell assembly 10, 20 placed in the open case 300 and each connected to a corresponding external terminal. The cell assembly 10, 20 may be bonded to the inner surface of the case members 310 and 320, respectively. An adhesive containing, for example, PET (polyethylene terephthalate) or nylon is preferred as an adhesive for fixing each cell assembly to the case 300. Such adhesives have excellent recyclability because their adhesive strength weakens in the presence of strong acids. Details of the cell assembly 10, 20 will be described later.

[0033] A recess 351 (claw receiving portion) is provided on the surface F1 of the case member 310. A protrusion 352 (claw portion) is provided on the surface F1 of the case member 320. The recess 351 and the protrusion 352 are configured to be connectable to each other.

[0034] After the cell assemblies 10 and 20 are placed in the case 300, the case 300 is closed by the hinge portion 330. Specifically, the case 300 is closed so that the recessed portion 351 and the protruding portion 352 are coupled together. The recessed portion 351 and the protruding portion 352 are mechanically coupled together, for example, by a snap-fit ​​structure. The bottom of FIG. 2 shows the closed state of the case 300. The protruding portion 352 is fitted into the recessed portion 351 to form a coupled portion (coupled portion 350) between the case member 310 and the case member 320 (see the enlarged view of the snap-fit ​​structure in FIG. 2). For example, the recessed portion 351 and the protruding portion 352 are fitted together at the coupled portion 350, thereby coupling the case member 310 and the case member 320 together. This completes the battery 100 shown in FIG. 1. In the battery 100, the surface F1 of the case 300 includes the coupled portion 350, and the surface F2 of the case 300 includes the hinge portion 330. Case member 310 constitutes the +Y side portions of case 300 relative to hinge portions 330 (or connecting portions 350) of faces F1, F2, F5, and F6, and face F3. Case member 320 constitutes the −Y side portions of case 300 relative to hinge portions 330 (or connecting portions 350) of faces F1, F2, F5, and F6, and face F4. The case 300 may be sealed by joining (e.g., welding or bonding) the gaps between case member 310 and case member 320 at face F1. Each cell assembly may be fixed to the inner surface (face F1) of case 300 by injecting adhesive through the gaps between the case members. However, sealing case 300 is not required, and case 300 may be open. For example, openings (e.g., slits) may be formed in case 300 instead of sealing holes 323. Furthermore, heat dissipation holes may be formed in portions of case 300 corresponding to the energy storage cells.

[0035] As described above, the case can be opened and closed by the hinge portion 330 during the manufacturing process of the battery 100, which facilitates the manufacturing of the battery 100. The cell assemblies 10 and 20 will now be described.

[0036] 1 and 2, the cell connected body 10 includes four storage cells 11 to 14 arranged in the X direction and three connection parts 2 that electrically connect the storage cells to each other. The storage cells 11 to 14 are connected in a row in the X direction within a case 300. The cell connected body 20 includes four storage cells 21 to 24 arranged in the X direction and three connection parts 2 that electrically connect the storage cells to each other. The storage cells 21 to 24 are connected in a row in the X direction within the case 300. In this manner, the cell connected body 10 and the cell connected body 20 are arranged parallel to the X direction. Each of faces F1 to F4 of the case 300 extends in the connection direction (X direction) of the cell connected bodies 10 and 20. Each of faces F5 and F6 of the case 300 covers the end portions of the cell connected bodies 10 and 20 in the X direction. Each of the storage cells included in the cell connected bodies 10 and 20 is configured to be able to store electricity.

[0037] The cell connected bodies 10 and 20 are arranged such that the positions of the storage cells and the connection parts are aligned. The storage cells 11, 12, 13, and 14 included in the cell connected body 10 face the storage cells 21, 22, 23, and 24 included in the cell connected body 20 in the Y direction, respectively. Connection terminals T11 and T12 are provided at the +X side end (storage cell 11) and the -X side end (storage cell 14) of the cell connected body 10, respectively. Connection terminals T21 and T22 are provided at the +X side end (storage cell 21) and the -X side end (storage cell 24) of the cell connected body 20, respectively.

[0038] In this embodiment, the cell connected body 10 and the cell connected body 20 basically have the same configuration. Therefore, hereinafter, when there is no need to distinguish between the power storage cells 11 to 14 and 21 to 24, they will be referred to as "power storage cells 1."

[0039] FIG. 3 is a diagram illustrating the configuration of each of the cell connected bodies 10 and 20. As shown in FIG. 3, each cell connected 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 cell connected body is configured such that the energy storage cells 1 and the connection portions 2 are arranged alternately. In each of the cell connected bodies 10 and 20, 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. The energy storage cells 11 to 14 and 21 to 24 are configured from the same energy storage cells 1. By forming the cell connected bodies 10 and 20 using common energy storage cells 1, the manufacture of the battery 100 becomes easier and the manufacturing cost can be reduced.

[0040] 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.

[0041] 3 (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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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 exterior body 160 is provided on the surfaces of the two wound bodies 110A and 110B. The laminated exterior body 160 is, for example, a laminated film, and is provided on the surfaces of the energy storage cells 1.

[0049] 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.

[0050] In the lower part of FIG. 3, a first and a second variant of the connection part 2 are shown.

[0051] The connection portion 2A according to the first modification further includes a metal plate 180 provided between the protrusions 144A and 144B to be connected. In the connection portion 2A, the protrusions 144A and 144B are not in contact with each other but are electrically connected via the metal plate 180. Each of the protrusions 144A and 144B is joined (for example, ultrasonically bonded) to the metal plate 180. Providing the highly rigid metal plate 180 between the protrusions 144A and 144B to be connected facilitates ultrasonic bonding. Ultrasonic bonding makes it less likely that a brittle alloy layer will be formed.

[0052] The connection portion 2B according to the second modification further includes a clad material 190 provided between the protrusions 144A and 144B to be connected. In the connection portion 2B, the protrusions 144A and 144B are not in contact with each other but are electrically connected via the clad material 190. The clad material 190 is a dissimilar metal bonding material and includes a first metal portion 191 and a second metal portion 192. The first metal portion 191 and the second metal portion 192 are joined (e.g., laser welded) to the protrusions 144A and 144B, respectively. The first metal portion 191 and the second metal portion 192 may be formed of the same material as the protrusions 144A and 144B, respectively. In one example, the positive electrode side protrusion 144A made of aluminum is joined to the first metal portion 191 containing aluminum, and the negative electrode side protrusion 144B made of copper is joined to the second metal portion 192 containing copper.

[0053] Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 1. Fig. 4 shows only the pair of storage cells 13 and 23 as a representative, but other pairs of storage cells facing each other in the Y direction (the pair of storage cells 11 and 21, the pair of storage cells 12 and 22, and the pair of storage cells 14 and 24) also have the same structure.

[0054] The case 300 is made of resin and has insulating properties. This electrically insulates the case 300 from the components inside the case 300. Heat dissipation may be improved by omitting unnecessary laminate films (for example, laminate exterior bodies where the energy storage cells are joined). In the case 300, a region R as shown in FIGS. 1 and 4 exists between the +Z side surface of each energy storage cell and the inner surface (top surface) of the case. The region R may be provided with at least one of a heat management system (for example, a heater and / or a temperature sensor), a gas exhaust system (for example, a gas flow path and / or a pressure sensor), an FPC (flexible printed circuit board), and wiring connected to the connector 313. The devices and / or sensors provided in the region R may be connected to the connector 313.

[0055] FIG. 5 is a diagram illustrating the functions and effects of the battery 100. In a configuration in which electrically connected cell assemblies 10 and 20 are housed in a bottomed, cylindrical case 400 having an opening on the +X-side end face, as in the reference example in FIG. 5 , it may be difficult to insert the cell assemblies 10 and 20 into the case 400. Furthermore, in this reference example, a lid member is required to close the opening of the case 400 in order to seal the interior of the case 400. In contrast, the battery 100 shown in FIGS. 1 to 4 is provided with a hinge 330 that opens and closes the case 300. Therefore, after the cell assemblies 10 and 20 are inserted into the case 300 with the case 300 open by the hinge 330, the case 300 can be closed by the hinge 330. This battery 100 does not require an additional lid member. Furthermore, since the hinge portion 330 is formed along the X direction, a large opening is easily formed when the case 300 is opened by the hinge portion 330. The wide entrance (opening) of the case 300 makes it easier to insert the cell assemblies 10 and 20 into the case 300.

[0056] FIG. 6 shows the case 300 as well as first to third modified examples of the case 300. In FIG.

[0057] The case 300A according to the first modification has, instead of the hinge portion 330, a band-shaped hinge portion 330A that is wider than the hinge portion 330. Like the hinge portion 330, the hinge portion 330A is also formed to be long in the X direction (the connection direction of the housed cell assembly). However, the hinge portion 330A is flexible. When the case 300A is closed, the hinge portion 330A flexes and curves so as to protrude outward from the case 300A.

[0058] A case 300B according to the second modification includes case members 310B, 320B, and a hinge portion 330B instead of case members 310, 320, and hinge portion 330. Case member 310B has a rectangular prism shape (e.g., a hexagonal prism shape). Case member 310B (first case member) has a storage portion (a space for storing a cell assembly) and a recessed portion 351B. Case member 320B (second case member) does not have a storage portion and functions as a lid member that closes the opening of case member 310B. Case member 320B has a protruding portion 352B. Case member 310B, case member 320B, and hinge portion 330B are each formed to be elongated in the X direction (the connection direction of the stored cell assembly). Recess 351B and protrusion 352B are formed on the end portions of case member 310B and case member 320B opposite hinge portion 330B, respectively. Recess 351B and protrusion 352B are configured to be interlocking. When case 300B is closed by hinge portion 330B so that recess 351B fits into protrusion 352B, a joint portion (a portion where case member 310B and case member 320B are joined) is formed on the surface opposite hinge portion 330B. The structure that fastens case member 320B to case member 310B at the joint portion may be a snap-fit ​​structure, or may be a structure that fastens case member 320B to case member 310B by frictional force alone.

[0059] A case 300C according to the third modification includes case members 310C, 320C, and a hinge portion 330C instead of the case members 310 and 320 and the hinge portion 330. The case member 310C (first case member) has a cylindrical shape with its longitudinal direction aligned with the X direction (the connection direction of the housed cell assembly). The case member 310C has a housing portion (a space for housing the cell assembly) and a recessed portion 351C. The case member 310C is formed in a cylindrical shape with a bottom and an opening at one end in the X direction. The case member 320C (second case member) does not have a housing portion and functions as a lid member that closes the opening of the case member 310C. The case member 320C has a protruding portion 352C. The hinge portion 330C is elongated in a direction perpendicular to the X direction. The case members 310C and 320C can rotate around the hinge portion 330C as a rotation axis. Each of the recess 351C and the protrusion 352C has a ring shape that runs from one end of the hinge portion 330C back to the other end of the hinge portion 330C. The recess 351C and the protrusion 352C are configured to be interlocking with each other. When the case 300C is closed by the hinge portion 330C so that the recess 351C interlocks with the protrusion 352C, a ring-shaped joint (a portion where the case member 310C and the case member 320C are joined) is formed. Note that a storage portion (a space for storing the cell assembly) may be formed not only in the case member 310C but also in the case member 320C.

[0060] Each case (cases 300, 300A, 300B, 300C) may be formed of a material other than resin. For example, each case may be formed of metal (e.g., aluminum). The first case member, the second case member, and the hinge portion may be formed of the same material or different materials. The hinge portion may be a hinge-like part (e.g., a flat hinge, a removable hinge, a flush hinge, a pivot hinge, an angle hinge, a slide hinge, a drop hinge, a sewing machine hinge, or a long hinge) formed separately from each case member.

[0061] The number of connected cell bodies housed in each case is not limited to two and can be any number. The number of connected cell bodies housed in a case may be three or more, or may be one. The configuration of each connected cell body is not limited to the configuration shown in FIG. 3. Each connected cell body may include energy storage cells of different sizes or different shapes. The number of energy storage cells included in each connected cell body is not limited to four and can be changed as appropriate. The number of energy storage cells included in each connected cell body may be less than four, may be 5 to 19, or may be 20 or more.

[0062] The battery 100 described above and the battery according to the modified example thereof can function as a power storage device on its own. However, a plurality of such batteries may be combined to form a module. Furthermore, the battery 100 and the battery according to the modified example thereof may be mounted on, for example, a mobile body. Examples of mobile bodies include automobiles (electric vehicles, hybrid vehicles, etc.), vehicles other than automobiles (ships, airplanes, etc.), mobile machines (agricultural machines, construction machines, etc.), and unmanned mobile bodies (automated guided vehicles, robots, etc.). However, the use of the power storage device is arbitrary, and it may be for stationary use.

[0063] The various features of the power storage device described above (the features described in the embodiments and modifications) may be implemented in any combination. The power storage device may be applied to devices other than vehicles.

[0064] 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]

[0065] 1, 11 to 14, 21 to 24 storage cells, 2, 2A, 2B connection parts, 10, 20 cell connecting body, 100 battery, 300, 300A, 300B, 300C case, 310, 310B, 310C, 320, 320B, 320C case members, 330, 330A, 330B, 330C hinge part, 350 coupling part.

Claims

1. A power storage device including a case, The case includes a hinge portion that opens and closes the case, the case accommodates a cell assembly; The cell assembly includes a plurality of power storage cells and a connection portion that electrically connects the power storage cells to each other.

2. The case has a rectangular parallelepiped shape, the plurality of storage cells are connected in a first direction, the case has a first surface, a second surface, a third surface, and a fourth surface extending in the first direction, and a fifth surface and a sixth surface located at both ends in the first direction; the first surface and the second surface face each other in a second direction perpendicular to the first direction, the third surface and the fourth surface face each other in a third direction perpendicular to each of the first direction and the second direction, the second surface includes the hinge portion, the case includes a first case member and a second case member connected via the hinge portion, The power storage device according to claim 1 , wherein the first surface includes a joint portion where the first case member and the second case member are joined.

3. The power storage device according to claim 2 , wherein the hinge portion is a portion formed to have a thin plate thickness on the second surface and is formed along the first direction.

4. The power storage device according to claim 2 , wherein the connecting portion has a snap-fit ​​structure.

5. 5. The power storage device according to claim 1, wherein the case is made of resin.

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