Power storage device and vehicle

Abstract

A power storage device (100) comprises a first cell connection body (10) and a second cell connection body (20) that are electrically connected to each other. Each of the first cell connection body and the second cell connection body includes a plurality of power storage cells, and one or more connection parts that electrically connect adjacent power storage cells among the plurality of power storage cells. Each of the first cell connection body and the second cell connection body is disposed in a first direction (X direction). At least one of the connection parts included in the first cell connection body overlaps with one of the power storage cells of the second cell connection body in a second direction (Y direction) orthogonal to the first direction.

Description

Electricity storage device, vehicle

[0001] The present disclosure relates to a power storage device and a vehicle equipped with the power storage device.

[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.

[0003] Special Publication No. 2023-502457

[0004] In the energy storage device described in Patent Document 1, a plurality of electrode assembly sets connected in series and arranged in a row are disposed in a case (housing). In this energy storage device, the electrode assembly sets correspond to energy storage cells. Hereinafter, a series of a plurality of energy storage cells connected in a row will be referred to as a "cell series."

[0005] In order to improve the volumetric energy density of the power storage device, it is advantageous to arrange multiple cell units in parallel inside the case, rather than just one cell unit. However, if the cell units in each row are aligned, weak parts of the cell units in each row will overlap, which can result in a problem of reduced impact resistance of the power storage device.

[0006] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to improve the impact resistance of an electricity storage device including a plurality of cell connected bodies.

[0007] According to an embodiment of a first aspect of the present disclosure, there is provided an energy storage device as described below. (Item 1) The energy storage device includes a first cell string and a second cell string that are electrically connected. Each of the first cell string and the second cell string includes a plurality of energy storage cells and one or more connection parts that electrically connect adjacent energy storage cells in the plurality of energy storage cells. Each of the first cell string and the second cell string is arranged in a first direction. At least one of the connection parts included in the first cell string overlaps with an energy storage cell of the second cell string in a second direction that is perpendicular to the first direction.

[0008] In a cell assembly having connection portions provided between the energy storage cells as described above, the rigidity of the connection portions tends to be lower than the rigidity of the energy storage cells. Therefore, in the energy storage device, the first cell assembly and the second cell assembly are arranged so that the connection portions of the first cell assembly overlap the energy storage cells of the second cell assembly in the second direction. With this configuration, the connection portions of the first cell assembly are reinforced by the energy storage cells of the second cell assembly, thereby improving the impact resistance of the energy storage device. The connection portions may be conductive members. The connection portions may be portions where electrodes of adjacent energy storage cells are connected. The first cell assembly and the second cell assembly may be electrically connected by connecting an electrode of the first cell assembly and an electrode of the second cell assembly. The electrode of the first cell assembly and the electrode of the second cell assembly may be connected by coming into contact with each other, or may be connected via a conductive member provided between the electrodes. The positive electrode of the first cell assembly and the negative electrode of the second cell assembly may be connected. The positive electrode of the first cell connected body may be connected to the positive electrode of the second cell connected body. The first cell connected body and the second cell connected body may be connected in series or in parallel.

[0009] (Item 2) In the energy storage device according to item 1, two or more connection portions included in the first connected cell body overlap with the energy storage cells of the second connected cell body in the second direction.

[0010] According to the above configuration, it is possible to reinforce the multiple connection portions included in the first cell connected body.

[0011] (Item 3) In the energy storage device according to item 1 or 2, all of the connection portions included in the first connected cell body overlap with the energy storage cells of the second connected cell body in the second direction.

[0012] According to the above configuration, it is possible to reinforce all of the connection portions included in the first cell connected body.

[0013] (Item 4) In the energy storage device according to any one of Items 1 to 3, all of the connection portions included in the second connected cell body overlap with the energy storage cells of the first connected cell body in the second direction.

[0014] The above configuration makes it possible to reinforce all of the connections included in the second cell connected body. Furthermore, the combination of the configurations of paragraphs 3 and 4 reinforces all of the connections included in the first and second cell connected bodies, thereby improving the shock resistance of the energy storage device in particular.

[0015] (Item 5) In the energy storage device according to any one of Items 1 to 4, the length in a first direction of each of the plurality of energy storage cells included in the first cell connected body is a first dimension. The length in the first direction of each of the plurality of energy storage cells included in the second cell connected body is a second dimension that is longer than the first dimension.

[0016] As described above, by making the dimensions (more specifically, the lengths in the first direction) of the plurality of energy storage cells the same, it becomes easier to manufacture each of the cell strings. This reduces the manufacturing cost of the energy storage device. Furthermore, by making the energy storage cells of the first cell string and the energy storage cells of the second cell string have different dimensions, it becomes easier to arrange the first and second cell strings so that at least one connection portion included in the first cell string overlaps with the energy storage cell of the second cell string in the second direction.

[0017] (Item 6) In the energy storage device described in any one of Items 1 to 4, each of the plurality of energy storage cells included in the first cell connected body and each of the plurality of energy storage cells included in the second cell connected body have the same length in the first direction.

[0018] By making the dimensions (more specifically, the lengths in the first direction) of all the energy storage cells included in the first and second cell connected bodies the same, it becomes easier to manufacture the energy storage cells and assemble the energy storage device, thereby reducing the manufacturing cost of the energy storage device.

[0019] (7) In the electricity storage device according to the 6th aspect, a spacer is provided on at least one of the first cell connected body and the second cell connected body.

[0020] By providing a spacer as described above, it becomes easier to arrange the storage cells of the first cell assembly and the second cell assembly with a predetermined offset so that at least one connection portion included in the first cell assembly overlaps with the storage cells of the second cell assembly in the second direction.

[0021] (Item 8) In the energy storage device described in any one of Items 1 to 4, each of the plurality of energy storage cells included in the first cell assembly has the same length in the first direction, and the second cell assembly includes a plurality of energy storage cells having different lengths in the first direction.

[0022] By making the dimensions (more specifically, the lengths in the first direction) of the plurality of energy storage cells in the first cell string the same, manufacturing of the energy storage cells and assembly of the energy storage device are facilitated, thereby reducing the manufacturing cost of the energy storage device. Furthermore, by including a plurality of energy storage cells with different dimensions in the second cell string, it is easy to arrange the second cell string so that at least one connection portion included in the first cell string overlaps with an energy storage cell of the second cell string in the second direction.

[0023] (Item 9) In the energy storage device according to any one of items 1 to 8, the first cell connected body is fixed to the second cell connected body via a fixing member.

[0024] According to the above configuration, the first cell connected body is fixed to the second cell connected body, and misalignment is less likely to occur.

[0025] (10) In the energy storage device according to any one of the first to ninth aspects, a fixing member fixes the energy storage cells of the first connected cell body to the energy storage cells of the second connected cell body.

[0026] As described above, by fixing the power storage cells to each other, reinforcement by the power storage cells tends to be strong.

[0027] (Item 11) The energy storage device according to any one of Items 1 to 10 further includes a case that houses the first cell connected body and the second cell connected body. The number of energy storage cells housed in the case is 6 to 12.

[0028] According to the above configuration, it is easy to obtain an electricity storage device that has a high volumetric energy density and excellent impact resistance.

[0029] (Item 12) The energy storage device according to any one of Items 1 to 11 further includes a case that houses the first cell connected body and the second cell connected body. The case has a rectangular parallelepiped outer shape. The case has four faces extending in a first direction and two end faces that are pairs of faces located at both ends in the first direction. The four faces include first opposing faces that are a pair of faces that face in a second direction, and second opposing faces that are a pair of faces that face in a third direction that is perpendicular to both the first direction and the second direction.

[0030] According to the above configuration, it is easy to obtain an electricity storage device that has a high volumetric energy density and excellent impact resistance.

[0031] (Item 13) In the power storage device according to item 12, the area of ​​the second opposing surface is smaller than the area of ​​the first opposing surface.

[0032] According to the above configuration, it is easy to obtain an electricity storage device that has a high volumetric energy density and excellent impact resistance.

[0033] According to an embodiment of a second aspect of the present disclosure, there is provided a vehicle as described below: (14th Item) The vehicle includes the power storage device according to any one of the first to thirteenth items.

[0034] In the vehicle, the shock resistance of the power storage device including a plurality of connected cell bodies is improved.

[0035] According to the present disclosure, it is possible to improve the impact resistance of an electricity storage device including a plurality of cell connected bodies.

[0036] 11 is a diagram for explaining the configuration of an energy storage device according to an embodiment of the present disclosure. FIG. 11 is a perspective view showing an enlarged view of the inside of a case of the energy storage device shown in FIG. 1. FIG. 11 is a diagram for explaining the configuration of a first cell connected body shown in FIG. 1. FIG. 11 is a diagram for explaining the configuration of a second cell connected body shown in FIG. 1. FIG. 11 is an exploded perspective view of an energy storage cell included in each cell connected body shown in FIG. 1. FIG. 11 is an enlarged view of a connection portion shown in FIG. 1. FIG. 11 is a cross-sectional view taken along line VII-VII in FIG. 1. FIG. 11 is a cross-sectional view taken along line VIII-VIII in FIG. 1. FIG. 11 is a diagram for explaining the operation and effect achieved by an energy storage device according to an embodiment of the present disclosure. FIG. 11 is a diagram showing a first modified example of the energy storage device shown in FIG. 1. FIG. 11 is a diagram showing a second modified example of the energy storage device shown in FIG. 1. FIG. 11 is a cross-sectional view taken along line XII-XII in FIG. 11. FIG. 11 is a diagram showing a third modified example of the energy storage device shown in FIG. 1. FIG. 11 is a diagram showing a fourth modified example of the energy storage device shown in FIG. 1. FIG. 11 is a diagram showing a fifth modified example of the energy storage device shown in FIG. 1. FIG. 11 is a diagram showing a sixth modified example of the energy storage device shown in FIG. 1. FIG. 11 is a diagram showing a seventh modified example of the energy storage device shown in FIG. 1. FIG. 11 is a diagram showing an eighth modified example of the energy storage device shown in FIG. 1. FIG. 11 is a diagram showing a ninth modified example of the energy storage device shown in FIG. 1. FIG. 11 is a diagram showing a tenth modified example of the energy storage device 25 is a diagram showing an eleventh modified example of the power storage device shown in Fig. 1. FIG. 26 is a diagram showing a twelfth modified example of the power storage device shown in Fig. 1. FIG. 27 is a diagram showing a thirteenth modified example of the power storage device shown in Fig. 1. FIG. 28 is a diagram showing a fourteenth modified example of the power storage device shown in Fig. 1. FIG. 29 is a diagram showing an example of a power storage module produced by combining a plurality of batteries shown in Fig. 1. FIG. 29 is a diagram showing an example of a vehicle equipped with the power storage module shown in Fig. 25.

[0037] 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 "-".

[0038] FIG. 1 is a diagram for explaining the configuration of a power storage device according to this embodiment. "Case internal structure diagram - Z" in FIG. 1 is a diagram of the contents of the case as viewed from the +Z side. "Case internal structure diagram - Y" in FIG. 1 is a diagram of the contents of the case as viewed from the +Y side. FIG. 2 is an enlarged perspective view showing the end of the +X side of the contents of the case before they are inserted into the case.

[0039] 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).

[0040] The battery 100 includes a case 300. The case 300 has a rectangular parallelepiped shape. The case 300 has four faces extending in the X direction and two end faces located at both ends in the X direction. Specifically, the case 300 has a first opposing surface (a face facing in the Y direction), a second opposing surface (a face facing in the Z direction), and a third opposing surface (two end faces in the X direction). The first opposing surfaces are a pair of surfaces facing in the Y direction. The second opposing surfaces are a pair of surfaces facing in the Z direction. The third opposing surfaces are a pair of surfaces located at both ends in the X direction. In this embodiment, the area of ​​the second opposing surfaces is smaller than the area of ​​the first opposing surfaces. Hereinafter, the dimension in the X direction will be referred to as the "length," the dimension in the Y direction will be referred to as the "width," and the dimension in the Z direction will be referred to as the "height." The length of the case 300 is greater than the width of the case 300. The length of the case 300 may be 250 mm or more and 5000 mm or less, for example, approximately 1000 mm. The width of the case 300 may be 10 mm or more and 1250 mm or less, for example, approximately 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 may be 10 mm or more and 1250 mm or less, for example, approximately 100 mm. However, the dimensions of the case 300 are not limited to the above. For example, in the case 300, the area of ​​the first opposing surface may be smaller than the area of ​​the second opposing surface, or the areas may be the same.

[0041] The case 300 includes a main body 310 and a lid 320. The main body 310 is, for example, a cylindrical housing with a bottom and an opening on the end face on the +X side, and houses the cell connected bodies 10 and 20. The lid 320 is a plate-like member (cover member) having an outer shape corresponding to the opening of the main body 310, and closes the opening on the +X side of the main body 310. The main body 310 and the lid 320 may be formed of the same material or different materials. Metal, for example, can be used as the material constituting each of the main body 310 and the lid 320. The case 300 may be an aluminum case. However, these materials can be changed as appropriate. For example, the lid 320 may be formed of an insulating material.

[0042] As shown in FIG. 2 , after the cell assembly 10 and 20 are inserted into the body 310, the body 310 and the lid 320 are joined together. The body 310 and the lid 320 are welded together, for example, by laser welding. The lid 320 has a sealing hole 321, an external terminal 322, and a connector 323. The sealing hole 321 may be a pressure adjustment hole that adjusts the pressure inside the case 300. The sealing hole 321 has a sealing structure, for example, a metal cap (outside the case) and a sealing member (inside the case). This sealing structure ensures airtightness inside the case 300. The external terminal 322 includes an electrode tab 322A joined to the connection terminal T1 ( FIG. 1 ) of the cell assembly 10 and an electrode tab 322B joined to the connection terminal T2 ( FIG. 1 ) of the cell assembly 20. The electrode tabs may be joined together by laser welding. Each of the electrode tabs 322A and 322B may have an insulating sealing structure made of ceramic around the periphery of the electrode, for example. In this embodiment, the electrode tabs 322A and 322B function as a negative electrode tab and a positive electrode tab, respectively. However, this is not limiting, and the polarities may be reversed, with the electrode tab 322B serving as a negative electrode tab and the electrode tab 322A serving as a positive electrode tab. The connector 323 includes, for example, an output terminal and an input terminal. The output terminal may be configured to output a detection signal indicating a state inside the case 300 (e.g., the temperature of each storage cell) detected by one or more sensors inside the case 300 to the outside of the case. For example, a temperature sensor may be provided for each storage cell inside the case 300. The input terminal may be configured to input a control signal from the outside of the case to one or more devices inside the case 300.

[0043] At least one of a pressure adjustment hole and a gas exhaust valve may be provided on the end surface on the −X side of main body 310. Furthermore, an opening may be formed on the end surface on the −X side of main body 310, similar to the end surface on the +X side of main body 310. Then, a lid formed separately from cylindrical main body 310 may be joined (for example, by laser welding) to the opening.

[0044] As shown in FIG. 1 , the cell assembly 10 includes five storage cells 11 to 15 and a connection portion 2A that electrically connects the storage cells to each other. The storage cells 11 to 15 are connected in a row in the X direction within the case 300. The cell assembly 20 includes three storage cells 21 to 23 and a connection portion 2B that electrically connects the storage cells to each other within the case 300. The storage cells 21 to 23 are connected in a row in the X direction within the case 300. As described above, the cell assembly 10 and the cell assembly 20 are arranged in the X direction, and these cell assembly 10 and 20 are arranged parallel to each other. The four surfaces of the case 300, specifically, the first opposing surface (the surface opposing the Y direction) and the second opposing surface (the surface opposing the Z direction), are elongated in the connection direction (X direction) of the cell assembly 10, 20. The two end surfaces of the case 300 in the X direction cover the X-direction ends of the cell assembly 10, 20. In this embodiment, the cell connected body 10, the cell connected body 20, the X direction, the Y direction, and the Z direction correspond to examples of the "first cell connected body," the "second cell connected body," the "first direction," the "second direction," and the "third direction" according to the present disclosure, respectively.

[0045] FIG. 3 is a diagram for explaining the configuration of the connected cell body 10. As shown in FIG. 3, the connected cell body 10 is composed of five storage cells 1A. The storage cells 11 to 15 shown in FIG. 1 are composed of the same storage cells 1A. By forming the connected cell body 10 using common storage cells 1A, the manufacturing of the connected cell body 10 becomes easier and the manufacturing cost can be reduced. In addition, connection parts 2A are provided between adjacent storage cells 1A. The connection parts 2A electrically connect the adjacent storage cells 1A. The connected cell body 10 is composed of the storage cells 1A and the connection parts 2A arranged alternately.

[0046] FIG. 4 is a diagram for explaining the configuration of the cell connected body 20. As shown in FIG. 4, the cell connected body 20 is composed of three storage cells 1B. The storage cells 21 to 23 shown in FIG. 1 are composed of the same storage cells 1B. By forming the cell connected body 20 using common storage cells 1B, the manufacturing of the cell connected body 20 becomes easier and the manufacturing cost can be reduced. In addition, connection parts 2B are provided between adjacent storage cells 1B. The connection parts 2B electrically connect the adjacent storage cells 1B. The cell connected body 20 is composed of storage cells 1B and connection parts 2B arranged alternately.

[0047] In this embodiment, the X-direction dimension D1 of the cell connected body 10 shown in FIG. 3 is the same as the X-direction dimension D2 of the cell connected body 20 shown in FIG. 4. The X-direction dimension D11 ( FIG. 3 ) of the energy storage cell 1A is shorter than the X-direction dimension D21 ( FIG. 4 ) of the energy storage cell 1B. In this embodiment, the X-direction dimension D12 ( FIG. 3 ) of the connection portion 2A is the same as the X-direction dimension D22 ( FIG. 4 ) of the connection portion 2B. The dimension D12 corresponds to the distance between two adjacent energy storage cells 1A in the cell connected body 10. The dimension D22 corresponds to the distance between two adjacent energy storage cells 1B in the cell connected body 20. However, these dimensions are not limited to this and can be changed as appropriate. For example, the dimension D1 and the dimension D2 may be different. Furthermore, the dimension D12 and the dimension D22 may be different.

[0048] In this embodiment, each of the energy storage cells 1A and 1B is a laminate cell having one or more wound bodies. In a laminate cell, one or more wound bodies that function as electrode bodies are covered with a laminate exterior body. In FIG. 2 , the energy storage cell is illustrated without the laminate exterior body. 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. Although the energy storage cells 1A and 1B differ in size, they basically have the same configuration, and therefore, hereinafter, when there is no need to distinguish between them, they will be referred to as "energy storage cell 1." Furthermore, since the connection portions 2A and 2B also basically have the same configuration, they will be referred to as "connection portion 2" when there is no need to distinguish between them.

[0049] Fig. 5 is an exploded perspective view of the energy storage cell 1. 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. Although not shown in Fig. 5, the two wound bodies 110A and 110B are covered by a laminate exterior body (see Figs. 7 and 8 described below).

[0050] The wound bodies 110A and 110B each have a coated portion 111A or 111B, an electrode tab 112A or 112B, and an electrode tab 113A or 113B. The coated portions 111A or 111B are regions of the electrode foil on the positive electrode sheet or the negative electrode sheet where an active material layer is provided. The electrode tabs 112A, 112B, 113A, and 113B are regions of the electrode foil on the positive electrode sheet or the negative electrode sheet where the electrode foil is exposed. The regions of the electrode foil where the active material layer is exposed correspond to uncoated portions 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.

[0051] 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.

[0052] 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 its dimension in the Y direction increases with increasing distance from the coated portions 111A, 111B (see FIG. 8 , described later). The terminal member 130A is connected to the end face on the +X side of the spacer 120A. The terminal member 130B is connected to the 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 bodies 110A and 110B are joined (e.g., laser welded) to each other via the terminal members 130A and 130B.

[0053] 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.

[0054] The support portion 142A is formed in a plate shape on the YZ plane. The protrusion portion 144A is formed in a plate shape on the XZ plane. The support portion 142A and the protrusion portion 144A are connected to each other. The support portion 142A and the protrusion portion 144A may be integrated. The current collecting terminal 140A is joined (for example, by laser welding) to the end surface on the +X side of the terminal member 130A.

[0055] The support portion 142B is formed in a plate shape on the YZ plane. The protrusion portion 144B is formed in a plate shape on the XZ plane. The support portion 142B and the protrusion portion 144B are connected to each other. The support portion 142B and the protrusion portion 144B may be integrated. The current collecting terminal 140B is joined (for example, by laser welding) to the end surface on the -X side of the terminal member 130B.

[0056] The cover 150A covers the end of the +X side of the energy storage cell 1. The end of the +X side of the energy storage cell 1 includes electrode tabs 112A and 112B. The cover 150B covers the end of the −X side of the energy storage cell 1. The end of the −X side of the energy storage cell 1 includes electrode tabs 113A and 113B. The covers 150A and 150B are provided with through holes h for the protrusions 144A and 144B, respectively. The protrusion 144A passes through the through hole h of the cover 150A and protrudes toward the +X side of the energy storage cell 1. The protrusion 144B passes through the through hole h of the cover 150B and protrudes toward the −X side of the energy storage cell 1.

[0057] 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 may be used as the electrode body instead of the wound body. The laminate may be a laminate in which a positive electrode sheet and a negative electrode sheet are stacked with a separator interposed therebetween.

[0058] In each of the cell connected bodies 10 and 20, the storage cells 1 are connected to each other via a connection portion 2. FIG. 6 is an enlarged view of the connection portion 2. As shown in FIG. 6, the connection portion 2 is located between two adjacent storage cells 1. The rigidity of the connection portion 2 is lower than the rigidity of the storage cells 1. Furthermore, the cell connected body 10 and the cell connected body 20 are electrically connected within the case 300 of the battery 100. Specifically, as shown in FIG. 1, the storage cell 15 located at the end on the −X side of the cell connected body 10 and the storage cell 23 located at the end on the −X side of the cell connected body 20 are electrically connected within the case 300 via, for example, a U-shaped connection portion 2C. While the connection portion 2C has a U-shaped cross section, each of the connection portions 2A and 2B has an I-shaped cross section. The connection portion 2C basically has the same structure as the connection portion 2A or 2B, except that it is formed in a different shape. The connection portion 2C may be an integrally molded product or a composite of multiple separately molded parts. For example, the connection portion 2C may be formed by connecting a protrusion 144B ( FIG. 5 ) protruding from the energy storage cell 15 and a protrusion 144B ( FIG. 5 ) protruding from the energy storage cell 23 via a conductive material (beam portion). The energy storage cell 11 located at the end on the +X side of the cell assembly 10 is electrically connected to the electrode tab 322A via the connection terminal T1. The energy storage cell 21 located at the end on the +X side of the cell assembly 20 is electrically connected to the electrode tab 322B via the connection terminal T2.

[0059] 1, all of the connection portions 2A (specifically, four connection portions) included in the cell connected body 10 overlap in the Y direction with any of the energy storage cells 21 to 23 of the cell connected body 20. Also, all of the connection portions 2B (specifically, two connection portions) included in the cell connected body 20 overlap in the Y direction with the energy storage cell 12 or 14 of the cell connected body 10.

[0060] Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 1. Fig. 8 is a cross-sectional view taken along line VIII-VIII in Fig. 1.

[0061] As shown in FIGS. 7 and 8 , the energy storage cell 1A (e.g., energy storage cell 13) of the cell assembly 10 and the energy storage cell 1B (e.g., energy storage cell 22) of the cell assembly 20 further include laminate exterior bodies 161 and 162, respectively. Each of the laminate exterior bodies 161 and 162 is, for example, a laminate film and covers the corresponding energy storage cell (see FIG. 5 ). An insulating layer 310a containing a resin such as PET (polyethylene terephthalate) is provided on the inner surface of the main body 310 of the case 300. This electrically insulates the case 300 from the components inside the case 300. However, the insulating layer 310a can be omitted for cases (housings) that have sufficient insulation properties. For example, the cell assembly 10 and 20 may be covered with an insulating film (insulating layer). By integrating multiple cell assembly units with the insulating film, insertion into the case 300 is facilitated.

[0062] Referring to FIG. 7 , an adhesive may be provided in a region R1 between the −Z-side end face of each of the storage cells 1A and 1B and the inner surface (bottom surface) of the main body 310. Such adhesive can fix each of the storage cells 1A and 1B to the case 300. Furthermore, a region R2 is formed between the +Z-side end face of each of the storage cells 1A and 1B and the inner surface (top surface) of the main body 310. 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 323 may be provided in the region R2. The devices and / or sensors provided in the region R2 may be connected to the connector 323 of the lid 320.

[0063] As shown in Fig. 8 , in the connection portion 2A, of two adjacent storage cells 1A (e.g., storage cells 11 and 12), a protrusion 144A protruding from one storage cell 1A (e.g., storage cell 12) is joined to a protrusion 144B protruding from the other storage cell 1A (e.g., storage cell 11). The joining method may be laser welding. The welded portion may also be protected with tape or the like. Note that the connection portion 2B also has basically the same structure as the connection portion 2A.

[0064] FIG. 9 is a diagram illustrating the functions and effects of the battery 100. As in the reference example in FIG. 9 , when the first and second cell connected bodies are aligned, weak portions (connections 2) of the cell connected bodies in each row overlap in the Y direction, which can result in a problem of reduced impact resistance of the battery. In contrast, in the battery 100, the cell connected bodies 10 and 20 are arranged so that at least one connection 2A (e.g., four connection portions 2A) of the cell connected body 10 overlaps with a storage cell 1B (one of the storage cells 21 to 23) of the cell connected body 20 in the Y direction. With this configuration, the connection 2A of the cell connected body 10 is reinforced by the storage cell 1B of the cell connected body 20, thereby improving the impact resistance of the battery 100. Furthermore, in the battery 100, the cell connected bodies 10 and 20 are arranged so that at least one connection portion 2B (for example, two connection portions 2B) of the cell connected body 20 and the storage cell 1A (any of the storage cells 11 to 15) of the cell connected body 10 overlap in the Y direction. With this configuration, the connection portion 2B of the cell connected body 20 is reinforced by the storage cell 1A of the cell connected body 10, thereby improving the impact resistance of the battery 100.

[0065] In the battery 100, the storage cells 11 to 15 included in the cell assembly 10 each have the same first dimension in the X direction. Furthermore, the storage cells 21 to 23 included in the cell assembly 20 each have a second dimension in the X direction that is longer than the first dimension. The first dimension corresponds to the dimension D11 shown in FIG. 3 . The second dimension corresponds to the dimension D21 shown in FIG. 4 . By making the dimensions of the multiple storage cells the same in this way, the manufacturing of each cell assembly becomes easier. This reduces the manufacturing cost of the battery 100. Furthermore, by having the storage cell 1A of the cell assembly 10 and the storage cell 1B of the cell assembly 20 have different dimensions, it becomes easier to arrange the cell assembly 10 and the cell assembly 20 so that the connection portion 2A of the cell assembly 10 and the storage cell 1B (any of the storage cells 21 to 23) of the cell assembly 20 overlap in the Y direction.

[0066] In this embodiment, the number of storage cells included in the case 300 is eight. The number of storage cells included in the case 300 is preferably six to twelve. A case 300 accommodating six to twelve storage cells is likely to function as a storage device with high volumetric energy density and excellent impact resistance. If the number of storage cells is too small, the effect of improving the volumetric energy density of the storage device is reduced. Conversely, if the number of storage cells is too large, it becomes difficult to stack the connection portion 2A of the cell connected body 10 and the storage cells 1B of the cell connected body 20 in the Y direction to an extent that sufficient impact resistance is obtained.

[0067] FIG. 10 is a diagram showing a first modified example of the battery shown in FIG. 1 . As shown in FIG. 10 , a battery 100A according to the first modified example includes cell connected bodies 30 and 40 arranged parallel to the X direction. The cell connected body 30 includes power storage cells 31 to 34 and a connection portion 2A that electrically connects the power storage cells to each other. The cell connected body 40 includes power storage cells 41 to 44 and a connection portion 2B that electrically connects the power storage cells to each other. The power storage cells 31 to 34 and 41 to 44 are formed from the same power storage cell 1C. The connection portion 2A and the connection portion 2B have the same configuration. The cell connected body 30 and the cell connected body 40 have the same configuration. However, the cell connected body 40 is arranged shifted toward the +X side by an offset amount D3 with respect to the cell connected body 30. As a result, all of the connection portions 2A (more specifically, three connection portions) included in the cell connected body 30 overlap with any of the energy storage cells 42 to 44 of the cell connected body 40 in the Y direction, and all of the connection portions 2B (more specifically, three connection portions) included in the cell connected body 40 overlap with any of the energy storage cells 31 to 33 of the cell connected body 30 in the Y direction. This configuration improves the impact resistance of the battery 100. The cell connected bodies 30 and 40 are electrically connected via the connection portions 2D. The connection portion 2D includes a beam portion formed in a plate shape in the Y-Z plane and first and second leg portions formed in a plate shape in the X-Z plane. The first leg portion is connected to the energy storage cell 34 located at the end of the cell connected body 30 on the -X side. The second leg portion is connected to the energy storage cell 44 located at the end of the cell connected body 40 on the -X side. The beam portion connects the first and second leg portions. The connecting portion 2D has a U-shaped cross section and basically has the same structure as the connecting portion 2C (FIG. 1), except that the length of the second leg in the X direction of the connecting portion 2D is longer than the length of the first leg in the X direction by an offset amount D3.

[0068] In the battery 100A, each of the storage cells 31 to 34 included in the cell assembly 30 (first cell assembly) and each of the storage cells 41 to 44 included in the cell assembly 40 (second cell assembly) have the same dimension D30 in the X direction. The dimension D30 corresponds to the dimension of the storage cell 1C in the X direction. By making all of the storage cells housed in the case 300 the same dimension, the manufacturing of the storage cells and the assembly of the battery are facilitated. This allows the manufacturing cost of the battery to be reduced.

[0069] Fig. 11 is a diagram showing a second modified example of the battery shown in Fig. 1. Fig. 12 is a cross-sectional view taken along line XII-XII in Fig. 11.

[0070] As shown in FIGS. 11 and 12 , the battery 100B according to the second modification has a configuration basically similar to that of the battery 100A shown in FIG. 10 . However, in the battery 100B, the cell connected body 30 is fixed to the cell connected body 40 via a fixing member 170. This makes it difficult for misalignment to occur between the cell connected body 30 and the cell connected body 40. Specifically, the fixing member 170 is wound around the X-axis, for example, to fix the energy storage cells of the cell connected body 30 to the energy storage cells of the cell connected body 40. Fixing the energy storage cells to each other facilitates stronger reinforcement by the energy storage cells. For example, the fixing member 170 is wound around the surfaces of the pair of energy storage cells 32 and 42. Similarly, the fixing member 170 is wound around the surfaces of the pair of energy storage cells 31 and 41, the pair of energy storage cells 33 and 43, and the pair of energy storage cells 34 and 44. This integrates the respective pairs. The energy storage cells can be easily and appropriately fixed to each other by integrating the cell assembly (two pairs of energy storage cells) by winding the fixing member 170. Furthermore, by integrating the cell connected bodies 30 and 40 as described above, the cell connected bodies 30 and 40 can be easily inserted into the main body 310 of the case 300.

[0071] The fixing member 170 may be a tape with adhesive on one or both sides. To improve recyclability, a tape that can be peeled off using a specific organic solvent may be used as the fixing member 170. When the battery 100B is a liquid-type battery, the fixing member 170 is preferably formed from a material resistant to the electrolyte. Using double-sided tape (a tape with adhesive on both sides) as the fixing member 170 makes it possible to fix the cell assemblies 30 and 40 to the case 300 without providing a separate adhesive in region R1. Furthermore, the adhesive properties of the fixing member 170 can also be used to fix devices and / or sensors provided in region R2. Furthermore, the double-sided tape facilitates peeling of the laminate exterior bodies 161 and 162, improving the recyclability of the battery. The double-sided tape may be tapered to form a stress concentration portion that facilitates peeling.

[0072] The fixing member 170 is not limited to tape. For example, a resin member, a heat-shrinkable member, an elastic body (e.g., a rubber band), or the like can also be used as the fixing member 170.

[0073] Fig. 13 is a diagram showing a third modified example of the battery shown in Fig. 1 . The third modified example is an example in which a fixing member 170 is applied to the battery 100 shown in Fig. 1 . As shown in Fig. 13 , a battery 100C according to the third modified example basically has the same configuration as the battery 100 shown in Fig. 1 . However, in the battery 100C, the cell connected body 10 is fixed to the cell connected body 20 via the fixing member 170. Each of the pair of storage cells 11 and 21, the pair of storage cells 12 and 21, the pair of storage cells 14 and 22, and the pair of storage cells 15 and 23 is fixed by winding the fixing member 170.

[0074] Fig. 14 is a diagram showing a fourth modified example of the battery shown in Fig. 1. As shown in Fig. 14, battery 100D according to the fourth modified example basically has the same configuration as battery 100C shown in Fig. 13. However, in battery 100D, fixing members 170 are wrapped around all combinations (pairs) of storage cells that face each other in the Y direction. This allows forces in the X direction to be transmitted via storage cells 11 to 15, 21 to 23 and the multiple fixing members 170, without passing through connection portions 2A and 2B. For example, when force is applied to the ends of the cell connected bodies 10 and 20 on the −X side when the cell connected bodies 10 and 20 are inserted into the case 300, the force can be transmitted in the following order: storage cell 15, fixing member 170, storage cell 23, fixing member 170, storage cell 14, fixing member 170, storage cell 22, fixing member 170, storage cell 12, fixing member 170, storage cell 21, fixing member 170, and storage cell 11. This improves the impact resistance of the battery 100D.

[0075] FIG. 15 is a diagram showing a fifth modified example of the battery shown in FIG. 1 . As shown in FIG. 15 , the battery 100E according to the fifth modified example basically has the same configuration as the battery 100A shown in FIG. 10 . However, in the battery 100E, a positioning spacer 500 is provided on the cell assembly 30. The spacer 500 is positioned between the end face on the +X side of the cell assembly 30 and the inner surface of the case 300. The spacer 500 has a length in the X direction that corresponds to the offset amount D3. This makes it easier to position the cell assembly 30 and the cell assembly 40 at positions shifted by the offset amount D3.

[0076] In the battery 100E shown in FIG. 15, of the cell connected bodies 30 and 40, only the cell connected body 30 is provided with a spacer, but spacers may be provided in both the cell connected bodies 30 and 40.

[0077] FIG. 16 is a diagram showing a sixth modified example of the battery shown in FIG. 1. As shown in FIG. 16, a battery 100F according to the sixth modified example basically has the same configuration as the battery 100A shown in FIG. 10. However, in the battery 100F, a storage cell 1D is used instead of the storage cell 1C. The storage cell 1D has a recess 171 and a protrusion 172. The recess 171 and the protrusion 172 are formed on the +Y side surface and the −Y side surface of the storage cell 1D, respectively. The recess 171 and the protrusion 172 are positioned at positions shifted in the X direction by an offset amount D3.

[0078] The battery 100F includes cell connected bodies 50A and 50B arranged parallel to each other in the X direction. The cell connected body 50A includes storage cells 51A to 54A and connection parts 2A that electrically connect the storage cells to each other. The cell connected body 50B includes storage cells 51B to 54B and connection parts 2B that electrically connect the storage cells to each other. The storage cells 51A to 54A and 51B to 54B are configured using the same storage cell 1D. Forming the cell connected bodies 50A and 50B using the same storage cell 1D facilitates manufacturing of the battery 100F and reduces manufacturing costs. Furthermore, the connection parts 2A and 2B have the same configuration. The cell connected body 50A and the cell connected body 50B have the same configuration.

[0079] The convex portion 172 of the storage cell 1D included in the cell connected body 50A engages with the concave portion 171 of the storage cell 1D included in the cell connected body 50B. This facilitates positioning of the cell connected body 50A and the cell connected body 50B. Furthermore, the engagement between the concave portion 171 and the convex portion 172 makes it less likely that misalignment will occur between the cell connected body 50A and the cell connected body 50B. The concave portion 171 has a shape corresponding to the convex portion 172. The shape of the convex portion 172 may be a columnar shape (cylindrical, rectangular columnar, etc.), a pyramidal shape (conical, pyramidal, etc.), a spherical shape, or a hemispherical shape. The convex portion 172 may be a positioning pin.

[0080] FIG. 17 is a diagram showing a seventh modified example of the battery shown in FIG. 1 . The seventh modified example is an example in which a fixing member 170 is applied to the battery 100F shown in FIG. 16 . As shown in FIG. 17 , a battery 100G according to the seventh modified example basically has the same configuration as the battery 100F shown in FIG. 16 . However, in the battery 100G, the cell connected body 50A is fixed to the cell connected body 50B via a fixing member 170. More specifically, each of the pair of storage cells 51A and 51B, the pair of storage cells 52A and 52B, the pair of storage cells 53A and 53B, and the pair of storage cells 54A and 54B is fixed by winding the fixing member 170. The fixing member 170 may be provided so as to cover the protrusions 172 of each of the storage cells 51B to 54B. In order to prevent the convex portion 172 from damaging the inner surface of the case 300 (e.g., the insulating layer 310a), the convex portion 172 protruding toward the inner surface of the case 300 may be covered with an elastic body (fixing member 170).

[0081] FIG. 18 is a diagram illustrating an eighth modification of the battery shown in FIG. 1 . As shown in FIG. 18 , the battery 100H according to the eighth modification has a configuration similar to that of the battery 100 shown in FIG. 1 . However, in the battery 100H, the connected cell bodies 10 and 20 are fixed by a fixing member 180. The fixing member 180 is wound around the entire connected cell bodies 10 and 20, for example, by using the Z axis as the rotation axis. By unifying the connected cell bodies 10 and 20 by winding the fixing member 180, misalignment between the connected cell bodies 10 and 20 is less likely to occur. Furthermore, unifying the connected cell bodies 10 and 20 makes it easier to insert the connected cell bodies 10 and 20 into the main body 310 of the case 300. The fixing member 180 may be a resin film (e.g., a film containing vinyl chloride resin, polyvinylidene chloride, polyethylene, or polyolefin). Alternatively, the fixing member 180 may be a heat-shrinkable sheet.

[0082] Fig. 19 is a diagram showing a ninth modified example of the battery shown in Fig. 1. The ninth modified example is an example in which a fixing member 180 is applied to the battery 100D shown in Fig. 14. As shown in Fig. 19, the battery 100I according to the ninth modified example basically has the same configuration as the battery 100D shown in Fig. 14. However, in the battery 100I, the fixing member 180 is wound around the cell connected bodies 10 and 20 shown in Fig. 14.

[0083] FIG. 20 is a diagram illustrating a tenth modified example of the battery shown in FIG. 1 , specifically a cross-sectional view corresponding to FIG. 8 . As shown in FIG. 20 , the battery 100J according to the tenth modified example basically has the same cross-sectional structure as that shown in FIG. 8 . However, in the battery 100J, spacers 510, 511, and 512 are provided between the inner surface (insulating layer 310a) of the main body 310 of the case 300 and the connected cell body 10. Spacers 520, 521, and 522 are also provided between the connected cell body 10 and the connected cell body 20. Each of the spacers 510 and 520 is located at the connection portion 2A of the connected cell body 10. The spacer 510 is located on the +Y side of the joint between the protrusions 144A and 144B. The spacer 520 is located on the −Y side of the joint between the protrusions 144A and 144B. Each of the spacers 510 and 520 has an O-shaped cross section and a hollow structure. This improves the impact resistance of the connection portion 2A. Spacers similar to the spacers 510 and 520 may be provided not only for the connection portion 2A but also for the connection portion 2B.

[0084] FIG. 21 is a diagram showing an eleventh modification of the battery shown in FIG. 1 . As shown in FIG. 21 , a battery 100K according to the eleventh modification includes cell connected bodies 60 and 70 arranged parallel to the X direction. The cell connected body 60 includes storage cells 61 to 64 and a connection portion 2A that electrically connects the storage cells to each other. The cell connected body 70 includes storage cells 71 to 74 and a connection portion 2B that electrically connects the storage cells to each other. Each of the cell connected bodies 60, 70 includes a plurality of storage cells that differ in length in the X direction. Specifically, the storage cells 61 and 74 have the same length in the X direction. The storage cells 62 to 64 and 71 to 73 each have a shorter length in the X direction than the storage cells 61, 74. In the battery 100K, the connection portion 2B between the storage cells 71 and 72 overlaps with the storage cell 61 in the Y direction at a portion P11. The connection portion 2B between the power storage cells 72, 73 overlaps with the power storage cell 61 in the Y direction at a position P12. The connection portion 2A between the power storage cells 61, 62 overlaps with the power storage cell 73 in the Y direction at a position P13. The connection portion 2B between the power storage cells 73, 74 overlaps with the power storage cell 62 in the Y direction at a position P14. The connection portion 2A between the power storage cells 62, 63 overlaps with the power storage cell 74 in the Y direction at a position P15. The connection portion 2A between the power storage cells 63, 64 overlaps with the power storage cell 74 in the Y direction at a position P16. In this battery 100K as well, the impact resistance is improved by the power storage cells reinforcing each connection portion.

[0085] FIG. 22 is a diagram showing a twelfth modification of the battery shown in FIG. 1 . As shown in FIG. 22 , a battery 100L according to the twelfth modification includes cell arrays 80 and 90 arranged parallel to the X direction. The cell array 80 includes storage cells 81 to 84 and a connection portion 2A that electrically connects the storage cells to each other. The cell array 90 includes storage cells 91 to 94 and a connection portion 2B that electrically connects the storage cells to each other. In the battery 100L, the connection portion 2B between the storage cells 91 and 92 overlaps with the storage cell 81 in the Y direction at a position P21. The connection portion 2A between the storage cells 81 and 82 overlaps with the storage cell 92 in the Y direction at a position P22. The connection portion 2B between the storage cells 92 and 93 overlaps with the storage cell 82 in the Y direction at a position P23. The connection portion 2A between the storage cells 82 and 83 overlaps with the storage cell 93 in the Y direction at a position P24. In this battery 100L as well, the shock resistance is improved by reinforcing each connection portion with the storage cells.

[0086] However, in battery 100L, connection 2A between storage cells 83 and 84 overlaps connection 2B between storage cells 93 and 94 in the Y direction at position P25. To protect these connection portions 2A and 2B and connection portion 2C, a reinforcing member 190 (e.g., an elastic member) may be provided at the end of case 300 on the -X side. Covering connection portions 2A, 2B, and 2C with reinforcing member 190 may ensure sufficient impact resistance.

[0087] FIG. 23 is a diagram showing a thirteenth modification of the battery shown in FIG. 1 . As shown in FIG. 23 , in a battery 100M according to the thirteenth modification, a case 300 accommodates six storage cells. Specifically, the battery 100M basically has the same configuration as the battery 100 shown in FIG. 1 . However, in the battery 100M, a cell assembly 10A is used instead of the cell assembly 10 ( FIG. 1 ). The cell assembly 10A includes storage cells 11, 15, and 16 and a connection portion 2A that electrically connects the storage cells to each other. The storage cell 16 is disposed between the storage cells 11 and 15 instead of the storage cells 12 to 14 ( FIG. 1 ). In this battery 100M as well, the connection portions are reinforced by the storage cells, thereby improving impact resistance.

[0088] FIG. 24 is a diagram showing a fourteenth modification of the battery shown in FIG. 1 . As shown in FIG. 24 , in a battery 100N according to the fourteenth modification, a case 300 accommodates twelve storage cells. Specifically, the battery 100N basically has the same configuration as the battery 100 shown in FIG. 1 . However, the battery 100N employs cell connected bodies 10B and 20B instead of the cell connected bodies 10 and 20 ( FIG. 1 ). The cell connected body 10B includes storage cells 11A, 11B, 12 to 14, 15A, and 15B and a connection part 2A that electrically connects the storage cells to each other. The storage cells 11A and 11B have a structure in which the storage cell 11 ( FIG. 1 ) is divided into two storage cells, and the storage cells are connected to each other by the connection part 2A. The storage cells 15A and 15B have a structure in which the storage cell 15 (FIG. 1) is divided into two storage cells, and the storage cells are connected by a connection portion 2A. The cell assembly 20B includes storage cells 21, 22A to 22C, and 23, and a connection portion 2B that electrically connects the storage cells to each other. The storage cells 22A, 22B, and 22C have a structure in which the storage cell 22 (FIG. 1) is divided into three storage cells, and the storage cells are connected by a connection portion 2B. In this battery 100N, each connection portion is reinforced by the storage cells, thereby improving impact resistance.

[0089] The above-described batteries 100 and 100A to 100N can function as a power storage device by themselves. However, a plurality of such batteries may be combined to form a module. FIG. 25 is a diagram showing an example of a power storage module including a plurality of batteries. The power storage module 200 shown in FIG. 25 includes a plurality of batteries 100. The plurality of batteries 100 may be electrically connected in series or in parallel. The power storage module 200 functions as a power storage device. Any of the batteries 100A to 100N may be used in place of the battery 100.

[0090] The above-described batteries 100 and 100A-100N, and the power storage module 200 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 power storage device may be used for any purpose, and may be for stationary use.

[0091] FIG. 26 is a diagram showing an example of a vehicle equipped with the power storage module shown in FIG. 25 . The vehicle 2000 shown in FIG. 26 includes a battery pack 1000. The battery pack 1000 includes a plurality of power storage modules 200 and functions as a power storage device. The vehicle 2000 is, for example, an electric vehicle configured to run using power output from the battery pack 1000. The battery pack 1000 may supply power to a traction motor mounted on the vehicle 2000. In the battery pack 1000, the power storage modules 200 are electrically connected to each other, for example, via a bus bar (not shown). The battery pack 1000 may include 100 or more power storage cells. The orientation of the power storage modules 200 mounted on the vehicle 2000 is arbitrary. For example, the −Z side surface of each battery of the power storage module 200 may face the direction of gravity (vertical direction), or conversely, the +Z side surface of each battery may face the direction of gravity.

[0092] The various features of the power storage device described above, specifically 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.

[0093] 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.

[0094] 1, 1A to 1D, 11 to 15, 21 to 23, 31 to 34, 41 to 44, 51A to 54A, 51B to 54B, 61 to 64, 71 to 74, 81 to 84, 91 to 94 storage cells, 2, 2A to 2D connection parts, 10, 10A, 10B, 20, 20B, 30, 40, 50A, 50B, 60, 70, 80, 90 cell connecting bodies, 100, 100A to 100N batteries, 170, 180 fixing members, 200 storage modules, 500 spacers, 1000 battery packs, 2000 vehicles.

Claims

1. An energy storage device comprising an electrically connected first cell string and a second cell string, wherein each of the first cell string and the second cell string includes a plurality of energy storage cells and one or more connection parts that electrically connect adjacent energy storage cells in the plurality of energy storage cells, each of the first cell string and the second cell string is arranged in a first direction, and at least one of the connection parts included in the first cell string overlaps with a energy storage cell of the second cell string in a second direction that is perpendicular to the first direction.

2. The energy storage device according to claim 1, wherein two or more of the connection portions included in the first cell string overlap with the energy storage cells of the second cell string in the second direction.

3. The energy storage device according to claim 1, wherein all of the connection portions included in the first cell string overlap with the energy storage cells of the second cell string in the second direction.

4. The energy storage device according to claim 3, wherein all of the connection portions included in the second cell string overlap with the energy storage cells of the first cell string in the second direction.

5. The energy storage device according to claim 1, wherein each of the plurality of energy storage cells included in the first cell array has a length in the first direction that is a first dimension, and each of the plurality of energy storage cells included in the second cell array has a length in the first direction that is a second dimension that is longer than the first dimension.

6. The energy storage device according to claim 1, wherein each of the plurality of energy storage cells included in the first cell string and each of the plurality of energy storage cells included in the second cell string have the same length in the first direction.

7. The electricity storage device according to claim 6, wherein a spacer is provided on at least one of the first cell connected body and the second cell connected body.

8. The energy storage device according to claim 1, wherein each of the plurality of energy storage cells included in the first cell array has the same length in the first direction, and the second cell array includes a plurality of energy storage cells having different lengths in the first direction.

9. The energy storage device according to claim 1, wherein the first cell connected body is fixed to the second cell connected body via a fixing member.

10. The energy storage device according to claim 9, wherein the fixing member fixes the energy storage cells of the first cell assembly to the energy storage cells of the second cell assembly.

11. The energy storage device according to claim 1, further comprising a case that houses the first cell assembly and the second cell assembly, and the number of energy storage cells housed in the case is 6 or more and 12 or less.

12. The energy storage device according to claim 1, further comprising a case that houses the first cell assembly and the second cell assembly, the case having a rectangular parallelepiped outer shape, the case having four faces extending in the first direction and two end faces that are pairs of faces located at both ends of the first direction, the four faces including first opposing faces that are a pair of faces facing in the second direction, and second opposing faces that are a pair of faces facing in a third direction that is perpendicular to both the first direction and the second direction.

13. The power storage device according to claim 12, wherein the area of ​​the second opposing surface is smaller than the area of ​​the first opposing surface.

14. A vehicle equipped with the electricity storage device according to any one of claims 1 to 13.

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