Power storage device

Abstract

A power storage device according to the present invention is provided with a power storage element and a spacer disposed at a position adjacent to the power storage element, wherein: the power storage element is provided with a container housing an electrode body; the container is provided with at least two recesses penetrating in the alignment direction of the power storage element and the spacer; the spacer is provided with a spacer body that overlaps the container when viewed from the alignment direction, and a spacer protrusion extending from the spacer body in the alignment direction and disposed within the recesses when viewed from the alignment direction; and the spacer protrusion performs positioning of the power storage element and the spacer.

Description

Power storage device

[0001] The present invention relates to an electricity storage device.

[0002] Conventionally, a battery module has been disclosed in which multiple rectangular battery cells are fixed in a housing as a stack, and then a wall is provided on the outside of the housing to hold the stack in place, and a cooling section is provided on this wall through which a refrigerant flows, thereby cooling the batteries.

[0003] JP 2016-181504 A

[0004] In this regard, cooling the battery cells by providing a cooling section on the wall of a container of a module that houses the battery cells has been considered. However, in conventional battery modules, fixing the battery cells to the housing requires fixing sections at the four corners of the battery cells to fix them to the housing, and also requires beams to connect the fixing sections. Therefore, the presence of these beams reduces the contact area between the battery cells and the cooling section, which could reduce cooling efficiency.

[0005] Therefore, an object of the present invention is to provide an electricity storage device that can suppress a decrease in cooling efficiency.

[0006] An energy storage device according to one embodiment of the present invention comprises an energy storage element and a spacer arranged adjacent to the energy storage element, wherein the energy storage element comprises a container for accommodating an electrode body, the container having at least two recesses penetrating in the alignment direction of the energy storage element and the spacer, the spacer comprising a spacer main body that overlaps the container when viewed from the alignment direction, and a spacer protrusion that extends from the spacer main body in the alignment direction and is arranged within the recesses when viewed from the alignment direction, and the spacer protrusion positions the energy storage element and the spacer.

[0007] According to the present invention, it is possible to provide an electricity storage device with improved cooling efficiency.

[0008] FIG. 1 is a perspective view showing the appearance of an energy storage device according to an embodiment. FIG. 2 is an exploded perspective view showing each component of the energy storage device according to the embodiment when disassembled. FIG. 3 is a perspective view showing the appearance of an energy storage element according to the embodiment. FIG. 4 is an exploded perspective view showing each component of the energy storage element according to the embodiment when disassembled. FIG. 5 is a perspective view showing the configuration of an electrode body according to the embodiment. FIG. 6 is a perspective view showing an intermediate spacer according to the embodiment. FIG. 7 is an enlarged plan view showing an end portion of the intermediate spacer according to the embodiment in the positive direction of the X-axis. FIG. 8 is an explanatory diagram showing the positional relationship of the intermediate spacer, the energy storage element, and the case according to the embodiment at the end portion in the positive direction of the X-axis. FIG. 9 is an explanatory diagram showing the positional relationship of the intermediate spacer, the energy storage element, and the case according to Modification 1. FIG. 10 is an explanatory diagram showing the positional relationship of the intermediate spacer, the energy storage element, and the case according to Modification 2. FIG. 11 is a perspective view showing an intermediate spacer having a connecting portion according to Modification 3. FIG. 12 is a perspective view showing an energy storage element according to Modification 4. FIG. 13 is an explanatory diagram showing a cover according to Modification 5. FIG. 14 is an explanatory diagram showing the bottom wall, the side wall, and the case cover according to the sixth modification.

[0009] (1) One aspect of the present invention provides an energy storage device comprising: an energy storage element; and a spacer arranged adjacent to the energy storage element; the energy storage element comprising a container for accommodating an electrode body; the container comprising at least two recesses penetrating in an alignment direction of the energy storage element and the spacer; the spacer comprising a spacer body overlapping the container when viewed from the alignment direction; and a spacer protrusion extending from the spacer body in the alignment direction and arranged within the recesses when viewed from the alignment direction; the spacer protrusion positioning the energy storage element and the spacer.

[0010] According to the energy storage device described in (1) above, when viewed from the arrangement direction, the spacer protrusions arranged within the recesses of the energy storage element containers are positioned from the spacer main body in a direction intersecting the arrangement direction and extend in the arrangement direction. Therefore, the spacer protrusions interfere with the inner wall surfaces of the recesses of the energy storage element containers, thereby positioning the energy storage elements and the spacer. In this case, the spacer protrusions are arranged within the recesses when viewed from the arrangement direction. In other words, the energy storage elements can be positioned even if the spacer protrusions are arranged so as not to protrude outside the recesses. The spacer protrusions do not get in the way of the outer surface of the container where the spacer protrusions do not protrude outside the recesses, making it easier for the cooling unit to come into contact with the outer surface. Therefore, the cooling efficiency for the energy storage elements can be improved.

[0011] (2) In the electricity storage device described in (1) above, the electricity storage element may have at least one of a terminal and a gas release valve disposed in the recess.

[0012] According to the energy storage device described in (2) above, when terminals are arranged in the recesses of the energy storage element container, the spacer protrusions and the terminals can be accommodated in the recesses, thereby preventing the space outside the energy storage element from being consumed. On the other hand, even when a gas release valve is arranged in the recesses, the spacer protrusions and the exhaust flow path can be accommodated in the recesses, thereby preventing the space outside the energy storage element from being consumed.

[0013] (3) In the electricity storage device described in (2) above, the spacer protrusion may have an opening through which at least one of the terminal and the gas release valve is exposed.

[0014] According to the storage device described in (3) above, the opening in the spacer convex portion exposes at least one of the terminal and the gas exhaust valve, thereby suppressing interference between the spacer convex portion and at least one of the terminal and the gas exhaust valve, and enabling smooth assembly.

[0015] (4) In the energy storage device described in any one of (1) to (3) above, the inner wall surface of the recess may have a first surface and a second surface that are perpendicular to each other when viewed from the arrangement direction, and the spacer protrusion may be formed in an L-shape having a first portion that runs along the first surface and a second portion that runs along the second surface.

[0016] According to the energy storage device described in (4) above, the spacer protrusions are formed in an L-shape, so that the first portion of the spacer protrusions is aligned along the first surface of the recess, and the second portion is aligned along the second surface of the recess, thereby covering most of the inner wall surface of the recess. This makes it possible for the spacer protrusions to suppress short circuits that may occur when, for example, a bus bar is placed in the recess.

[0017] (5) In the energy storage device described in any one of (1) to (4) above, the opposing surface of the spacer convex portion facing the inner wall surface of the concave portion may have a protrusion mark formed on it, the protrusion mark having been crushed by the inner wall surface of the concave portion.

[0018] According to the energy storage device described in (5) above, during manufacturing of the energy storage device, the protrusions formed on the opposing surfaces of the spacer protrusions are crushed by the inner wall surfaces of the recesses, leaving protrusion marks. By crushing these protrusions, the energy storage elements positioned by the spacer protrusions can be pressed against the cooling unit. This improves contact between the energy storage elements and the cooling unit, enabling more efficient cooling.

[0019] (6) In the energy storage device described in any one of (1) to (5) above, the energy storage device may include a plurality of the energy storage elements arranged in the alignment direction, and a plurality of the spacers arranged in the alignment direction and positioned to sandwich each of the plurality of energy storage elements.

[0020] According to the energy storage device described in (6) above, even if the energy storage device is provided with a plurality of spacers that sandwich each energy storage element for positioning, the cooling efficiency for each energy storage element can be improved.

[0021] (Embodiments) Hereinafter, with reference to the drawings, a description will be given of an energy storage device according to an embodiment of the present invention (including modifications thereof). Note that the embodiments described below all show comprehensive or specific examples. The numerical values, shapes, materials, components, component placement and connection configurations, manufacturing processes, and the order of manufacturing processes shown in the following embodiments are examples and are not intended to limit the present invention. In each drawing, dimensions and the like are not strictly illustrated. In each drawing, the same or similar components are assigned the same reference numerals. The names of the components (each component) in this embodiment are those used in this embodiment and may differ from the names of the components (each component) in the background art.

[0022] In the following description and drawings, the longitudinal direction of the energy storage element and the direction along the winding axis of the electrode body provided in the energy storage element are defined as the X-axis direction. The arrangement direction of the multiple energy storage elements and the thickness direction of the container of the energy storage element are defined as the Y-axis direction. The arrangement direction of the case lid and case body of the energy storage device, the arrangement direction of the bottom surface of the container body and the top surface of the lid of the container, or the up-down direction are defined as the Z-axis direction. These X-axis, Y-axis, and Z-axis directions intersect each other (orthogonal in this embodiment). Note that depending on the usage mode, the Z-axis may not be the up-down direction, but for convenience of explanation, the following description will be made assuming that the Z-axis is the up-down direction. In the following description, the term "insulation" means "electrical insulation."

[0023] In the following description, for example, the positive X-axis direction indicates the direction of the arrow on the X-axis, and the negative X-axis direction indicates the opposite direction to the positive X-axis direction. The same applies to the Y-axis and Z-axis directions. Furthermore, expressions indicating relative directions or attitudes, such as parallel and perpendicular, also include cases where the direction or attitude is not strictly that. For example, "two directions are perpendicular" does not only mean that the two directions are completely perpendicular, but also means that the two directions are substantially perpendicular, that is, there is a difference of, for example, about several percent. An insulating material has a volume resistivity of 1×10 6 Ωm or more, more preferably 1×10 7 It is preferable that the material be made of a material with a resistance of Ωm or more.

[0024] [Electricity Storage Device] First, a schematic configuration of an electricity storage device 1 according to the present embodiment will be described. Fig. 1 is a perspective view showing the appearance of the electricity storage device 1 according to the embodiment. Fig. 2 is an exploded perspective view showing each component of the electricity storage device 1 according to the embodiment.

[0025] The power storage device 1 is a device capable of charging with electricity from an external source and discharging electricity to an external source, and in this embodiment, has a substantially rectangular parallelepiped shape. The power storage device 1 is a battery module (battery assembly) used for power storage or power supply purposes. The power storage device 1 is used as a battery for driving or starting the engine of a mobile object such as an automobile, motorcycle, personal watercraft, boat, snowmobile, agricultural machinery, construction machinery, or electric railway vehicle. Examples of the automobile include an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and a fossil fuel (gasoline, diesel, liquefied natural gas, etc.) vehicle. Examples of the electric railway vehicle include a train, a monorail, a linear motor car, an automatic guided vehicle (AGV), and a hybrid train equipped with both a diesel engine and an electric motor. The power storage device 1 can also be used as a stationary battery for home or business use.

[0026] As shown in Fig. 1 , the energy storage device 1 includes a case 2. As shown in Fig. 2 , the case 2 accommodates a plurality of energy storage elements 10, a plurality of spacers 20, a plurality of bus bars (not shown), and the like. The energy storage device 1 also includes external terminals (positive electrode external terminals and negative electrode external terminals) for electrically connecting to an external device, but these are not shown or described here. In addition to the above components, the energy storage device 1 may also include restraining members (end plates, side plates, etc.) that restrain the plurality of energy storage elements 10, bus bar holders that hold the bus bars, bus bar covers, circuit boards that monitor or control the charge and discharge states of the energy storage elements 10, and electrical components such as relays, fuses, shunt resistors, and connectors.

[0027] The case 2 is a substantially rectangular parallelepiped (box-shaped) container (module case) that constitutes the exterior body (housing, outer shell) of the energy storage device 1. The case 2 is disposed outside the plurality of energy storage elements 10 and the plurality of spacers 20, etc., and secures the plurality of energy storage elements 10 and the plurality of spacers 20, etc., in predetermined positions to protect them from impacts and the like. The case 2 is a metal case formed from a metal member such as aluminum, aluminum alloy, stainless steel, iron, or plated steel sheet. Because the case 2 is a metal case, heat from each energy storage element 10 can be efficiently dissipated to the outside of the case 2, thereby cooling each energy storage element 10. In this way, the case 2 is an example of a cooling unit. If the case 2 is formed of a conductive material, the inner surface of the case 2 may be coated with an insulating material to ensure insulation from the energy storage elements.

[0028] 2, the case 2 includes a case main body 30 that constitutes the main body of the case 2, and a case lid 40 that constitutes the lid of the case 2. The case main body 30 is a rectangular cylindrical housing (chassis) with a bottom and an opening 31 formed in the positive direction of the Z axis, and accommodates a plurality of energy storage elements 10, a plurality of spacers 20, etc.

[0029] Specifically, the case body 30 includes a bottom wall 32 and a side wall 33. The bottom wall 32 is a flat, rectangular portion located at the end of the case body 30 in the negative Z-axis direction.

[0030] The side wall 33 is a rectangular annular wall extending in the positive Z-axis direction from the outer periphery of the bottom wall 32, and is provided continuously around the entire circumference of the bottom wall 32. The opening 31 is located inside the side wall 33. A pair of exhaust ports 37 is provided in the side wall 33 at a portion facing the negative Z-axis direction. Of the pair of exhaust ports 37, one exhaust port 37 is located at a corner facing the negative Z-axis direction and the negative X-axis direction, and the other exhaust port 37 is located at a corner facing the negative Z-axis direction and the positive X-axis direction. Each exhaust port 37 connects the inside and outside of the case 2, and exhausts gas discharged from each energy storage element 10 to the outside of the case 2.

[0031] The case lid 40 is a flat, rectangular member that closes the rectangular opening 31 of the case body 30. The case body 30 and the case lid 40 are hermetically sealed by being joined by welding, fusing, screwing, or the like. The case body 30 and the case lid 40 may be made of the same material or different materials.

[0032] As shown in Fig. 1, refrigerant pipes 950 are provided on the outer surface of the case 2 (not shown in Fig. 2). Specifically, the refrigerant pipes 950 are arranged in a bellows shape on the outer surfaces of two wall portions of the side wall 33 that face each other in the X-axis direction, on the lower surface of the bottom wall 32, and on the outer surface of the case lid 40. A refrigerant such as a gas or liquid flows through the refrigerant pipes 950. The refrigerant pipes 950 and the case 2 are joined by welding.

[0033] The energy storage element 10 is a secondary battery (single cell) that can charge and discharge electricity, and more specifically, a non-aqueous electrolyte secondary battery such as a lithium-ion secondary battery. The energy storage element 10 has a shape that is longer in the X-axis direction than in the Y-axis direction, specifically, a rectangular parallelepiped shape (rectangular, square) that is flattened in the Y-axis direction. In this embodiment, eight energy storage elements 10 are arranged side by side in the Y-axis direction. The size of the energy storage elements 10 and the number of the arranged energy storage elements 10 are not particularly limited, and for example, only one energy storage element 10 may be arranged. Each energy storage element 10 may be covered with an insulating film. A detailed description of the configuration of the energy storage elements 10 will be given later.

[0034] The spacer 20 is a member that is flat in the Y-axis direction and is arranged alongside the energy storage element 10 in the Y-axis direction to insulate and / or heat the energy storage element 10 from other members. The spacer 20 is an insulating plate or a heat insulating plate that is arranged adjacent to the energy storage element 10 in the positive or negative Y-axis direction of the energy storage element 10 and that insulates and / or heats the energy storage elements 10 from each other or the energy storage element 10 from the case 2. The spacer 20 is formed from an insulating material such as polycarbonate (PC), polypropylene (PP), polyethylene (PE), polystyrene (PS), polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyether ether ketone (PEEK), tetrafluoroethylene perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyethersulfone (PES), polyamide (PA), ABS resin, or a composite material containing any of these materials and a filler added thereto, or a material having heat insulating properties such as mica.

[0035] Of the spacers 20, the spacers 20 arranged between adjacent energy storage elements 10 are intermediate spacers 21, and the two spacers 20 arranged at the ends of the energy storage elements 10 in the Y-axis direction are end spacers 22. Of the two end spacers 22, at least one may be a reaction force adjustment spacer for restraining each energy storage element 10 within the case 2. All of the spacers 20 may be formed from the same material, or any of the spacers 20 may be formed from a material made of a different material. When viewed from the Y-axis direction, the spacer 20 has a shape based on a rectangle that is elongated in the X-axis direction, and each corner of the rectangle is cut out in a rectangular shape to form a spacer recess 211. Each spacer recess 211 corresponds to each recess (first recess 101 and second recess 102: described below) in the container 100 of the energy storage element 10. Therefore, in a stack in which the spacers 20 and the energy storage elements 10 are stacked and arranged in the Y-axis direction, the recesses of the energy storage elements 10 and the spacer recesses 211 of the spacers 20 are continuously aligned in the Y-axis direction. That is, the stack has a first space S1 at a corner facing the positive Z-axis direction and the negative X-axis direction, a second space S2 at a corner facing the positive Z-axis direction and the positive X-axis direction, a third space S3 at a corner facing the negative Z-axis direction and the negative X-axis direction, and a fourth space S4 at a corner facing the negative Z-axis direction and the positive X-axis direction. Each of the first space S1 to the fourth space S4 extends throughout the stack in the Y-axis direction. Bus bars are disposed in the first space S1 and the second space S2, and the third space S3 and the fourth space S4 serve as flow paths (exhaust flow paths) for gas exhausted from the energy storage elements 10. The third space S3 and the fourth space S4 are connected to the outside of the case 2 via the exhaust ports 37. The spacer 20 will be described in detail later.

[0036] The bus bar is connected (joined) to the terminals 300 of the plurality of energy storage elements 10. Specifically, the plurality of bus bars connect the terminals 300 of the plurality of energy storage elements 10 to each other and electrically connect the terminals 300 of the end energy storage elements 10 to external terminals. The connection form of the bus bar is not particularly limited, and the plurality of energy storage elements 10 may be connected in series or in parallel in any combination, or all of the energy storage elements 10 may be connected in series or in parallel. The bus bar and the terminals 300 are connected (joined) by welding or the like, but the connection form is not particularly limited. The bus bar is formed of a conductive member made of a metal such as aluminum, an aluminum alloy, copper, a copper alloy, or nickel, or a combination thereof, or a conductive member other than a metal.

[0037] [Energy Storage Element] An overall description of the energy storage element 10 according to the embodiment will be given with reference to Fig. 3 and Fig. 4. Fig. 3 is a perspective view showing the appearance of the energy storage element 10 according to the embodiment. Fig. 4 is an exploded perspective view showing the components of the energy storage element 10 according to the embodiment.

[0038] The energy storage element 10 is an energy storage element that can be charged with electricity from an external source and can discharge electricity to an external source, and in this embodiment has a substantially rectangular parallelepiped shape. The energy storage element 10 is not limited to a nonaqueous electrolyte secondary battery, and may be a secondary battery other than a nonaqueous electrolyte secondary battery, or may be a capacitor. The energy storage element 10 may not be a secondary battery, but may be a primary battery that can use stored electricity without the user having to charge it. Furthermore, the energy storage element 10 may be, for example, an all-solid-state lithium battery using a solid electrolyte, or a polymer lithium battery. The energy storage element 10 may also be a pouch-type energy storage element.

[0039] As shown in FIGS. 3 and 4 , the energy storage device 10 includes a container 100, a pair of terminals 300, and a pair of external gaskets 400. A pair of internal gaskets 500, a pair of current collectors 600, and an electrode assembly 700 are housed inside the container 100. Specifically, the components of the positive electrode (such as the terminals 300, the external gasket 400, the internal gasket 500, and the current collectors 600; the same applies below) are disposed on a first side surface 110 of the container 100 in the positive direction of the X axis. In other words, the first side surface 110 is the range from the end surface of the container 100 in the positive direction of the X axis in which the components of the positive electrode are disposed. For example, the first side surface 110 is a portion of the container 100 that is within a range of 1% to 10% of the length of the container 100 in the X axis direction from the end surface of the container 100 in the positive direction of the X axis.

[0040] The components of the negative electrode are disposed on the second side surface portion 120 of the container 100 in the negative X-axis direction. That is, the second side surface portion 120 is the range from the end surface of the container 100 in the negative X-axis direction where the components of the negative electrode are disposed. For example, the second side surface portion 120 is a portion in the X-axis direction that is within a range of 1% to 10% of the length of the container 100 from the end surface of the container 100 in the negative X-axis direction.

[0041] An electrolyte solution (non-aqueous electrolyte) is sealed inside the container 100, but is not shown in the figure. There are no particular restrictions on the type of electrolyte solution, and various types can be selected as long as they do not impair the performance of the energy storage element 10. In addition to the above components, spacers arranged on the sides, above, or below the electrode assembly 700, an insulating film that wraps around the electrode assembly 700, etc. may also be arranged.

[0042] The container 100 is a case having an outer shape (approximately rectangular parallelepiped shape) based on a rectangular parallelepiped shape that is elongated and flat in the X-axis direction. For example, the length of the container 100 in the X-axis direction is at least three times longer than its length in the Z-axis direction. In FIG. 3 , the reference rectangular parallelepiped shape is illustrated by a two-dot chain line L1. Specifically, the container 100 has an outer shape that is elongated and flat in the X-axis direction, with rectangular notches formed at the top and bottom of both ends in the X-axis direction. When viewed from the reference rectangular parallelepiped shape, each notch can be considered to form a recess. Of the multiple notches, a pair of notches located at the top of the container 100 each form a first recess 101, and a pair of notches located at the bottom of the container 100 each form a second recess 102. In other words, the first side surface portion 110 and the second side surface portion 120 of the container 100 each have a first recess 101 and a second recess 102 formed at different positions in the Z-axis direction so as to face each other in the Z-axis direction. A terminal 300 is disposed in the first recess 101, and a gas release valve 800 (see FIG. 4) is disposed in the second recess 102. The gas release valve 800 is a safety valve that releases pressure inside the container 100 when the pressure rises excessively.

[0043] Specifically, the first side surface portion 110 has a first upper side surface 111, a first top surface 112, a first middle side surface 113, a first bottom surface 114, and a first lower side surface 115, and is elongated in the Z-axis direction when viewed in the X-axis direction. The first upper side surface 111 is located at the top of the first side surface portion 110 and is a rectangular plane parallel to the YZ plane and elongated in the Z-axis direction. The first top surface 112 is a plane extending from the lower end of the first upper side surface 111 in the positive X-axis direction, and is a rectangular plane parallel to the XY plane and elongated in the X-axis direction. The first middle side surface 113 is a plane extending downward from the end of the first upper surface 112 in the positive X-axis direction, and is a rectangular plane parallel to the YZ plane and elongated in the Z-axis direction. The first lower surface 114 is a plane extending from the lower end of the first middle side surface 113 in the negative X-axis direction, and is a rectangular plane parallel to the XY plane and elongated in the X-axis direction. The first lower side surface 115 is a plane that extends downward from the end of the first lower surface 114 in the negative X-axis direction, and is a rectangular plane that is parallel to the YZ plane and elongated in the Z-axis direction.

[0044] The first recess 101 of the first side surface portion 110 is formed by a first upper side surface 111 and a first top surface 112, and is open at its end in the positive Z-axis direction and its end in the positive X-axis direction, penetrating in the Y-axis direction. In this way, the inner wall surface of the first recess 101 of the first side surface portion 110 has the first upper side surface 111 (an example of a first surface) and the first top surface 112 (an example of a second surface) that extend in different directions when viewed from the Y-axis direction.

[0045] The second recess 102 of the first side surface portion 110 is formed by a first lower surface 114 and a first lower side surface 115, and is open at its end in the negative Z-axis direction and its end in the positive X-axis direction, penetrating in the Y-axis direction. In this way, the inner wall surface of the second recess 102 of the first side surface portion 110 includes the first lower side surface 115 (an example of a first surface) and the first lower surface 114 (an example of a second surface) that extend in different directions when viewed from the Y-axis direction.

[0046] In other words, the first recess 101 of the first side surface portion 110 is a recess in which a corner portion of the container 100 in the positive X-axis direction and the positive Z-axis direction is recessed (cut out) into a quadrangular (L-shaped) shape when viewed from the Y-axis direction. The second recess 102 of the first side surface portion 110 is a recess in which a corner portion of the container 100 in the positive X-axis direction and the negative Z-axis direction is recessed (cut out) into a quadrangular (L-shaped) shape when viewed from the Y-axis direction.

[0047] The second side surface portion 120 has a second upper side surface 121, a second top surface 122, a second middle side surface 123, a second bottom surface 124, and a second lower side surface 125, and is elongated in the Z-axis direction when viewed in the X-axis direction. The second upper side surface 121 is located at the top of the second side surface portion 120 and is a rectangular plane parallel to the YZ plane and elongated in the Z-axis direction. The second top surface 122 is a plane extending from the lower end of the second upper side surface 121 in the negative X-axis direction and is a rectangular plane parallel to the XY plane and elongated in the X-axis direction. The second middle side surface 123 is a plane extending downward from the end of the second upper surface 122 in the negative X-axis direction and is a rectangular plane parallel to the YZ plane and elongated in the Z-axis direction. The second lower surface 124 is a plane extending from the lower end of the second middle side surface 123 in the positive X-axis direction and is a rectangular plane parallel to the XY plane and elongated in the X-axis direction. The second lower side surface 125 is a plane that extends downward from the end of the second lower surface 124 in the positive X-axis direction, and is a rectangular plane that is parallel to the YZ plane and elongated in the Z-axis direction.

[0048] The first recess 101 of the second side surface portion 120 is formed by a second upper side surface 121 and a second top surface 122, and the end portion facing the positive Z-axis direction and the end portion facing the negative X-axis direction are open and penetrate the Y-axis direction. In this way, the inner wall surface of the first recess 101 of the second side surface portion 120 has the second upper side surface 121 (an example of a first surface) and the second top surface 122 (an example of a second surface) that extend in different directions when viewed from the Y-axis direction.

[0049] The second recess 102 of the second side surface portion 120 is formed by a second lower surface 124 and a second lower side surface 125, and its end in the negative Z-axis direction and its end in the negative X-axis direction are open and penetrate the Y-axis direction. In this way, the inner wall surface of the second recess 102 of the second side surface portion 120 has the second lower side surface 125 (an example of a first surface) and the second lower surface 124 (an example of a second surface) that extend in different directions when viewed from the Y-axis direction.

[0050] In other words, the first recess 101 of the second side surface portion 120 is a recess in which a corner of the container 100 in the negative X-axis direction and the positive Z-axis direction is recessed (cut out) into a quadrangular shape when viewed from the Y-axis direction. The second recess 102 of the second side surface portion 120 is a recess in which a corner of the container 100 in the negative X-axis direction and the negative Z-axis direction is recessed (cut out) into a quadrangular shape when viewed from the Y-axis direction.

[0051] In this container 100, both end faces opposing each other in the Y-axis direction are long side faces 130. Each long side face 130 is a flat surface parallel to the XZ plane and elongated in the X-axis direction, and both end portions in the X-axis direction have shapes corresponding to the first side face portion 110 and the second side face portion 120.

[0052] Of the two end faces of the container 100 that face each other in the Z-axis direction, the end face in the positive Z-axis direction is the top face 140, and the end face in the negative Z-axis direction is the bottom face 150. The top face 140 is a rectangular flat surface that is parallel to the XY plane and elongated in the X-axis direction, connecting the upper end of the first upper side face 111 of the first side face portion 110 and the upper end of the second upper side face 121 of the second side face portion 120. The bottom face 150 is a rectangular flat surface that is parallel to the XY plane and elongated in the X-axis direction, connecting the lower end of the first lower side face 115 of the first side face portion 110 and the lower end of the second lower side face 125 of the second side face portion 120.

[0053] The container 100 includes a container body 160 and a lid 170, and is formed into a substantially rectangular parallelepiped shape by assembling the container body 160 and the lid 170. The container body 160 has a pair of long sides 130 and a bottom surface 150. The lid 170 has a first upper side surface 111, a first top surface 112, a first middle side surface 113, a first bottom surface 114, a first lower side surface 115, a second upper side surface 121, a second top surface 122, a second middle side surface 123, a second bottom surface 124, a second lower side surface 125, and a top surface 140.

[0054] Specifically, the container body 160 is a generally U-shaped metal plate that is open at the top when viewed from the X-axis direction. The container body 160 has flat long side wall portions that form a pair of long sides 130 at both ends in the Y-axis direction, and a flat, rectangular bottom wall portion that forms the bottom surface 150 at the end in the negative Z-axis direction.

[0055] The lid 170 is a metal plate that is open downward when viewed in the Y-axis direction. The lid 170 has a curved plate portion forming a first upper side surface 111, a first top surface 112, a first middle side surface 113, a first bottom surface 114, and a first bottom side surface 115 at its end in the positive X-axis direction, a curved plate portion forming a second upper side surface 121, a second top surface 122, a second middle side surface 123, a second bottom surface 124, and a second bottom side surface 125 at its end in the negative X-axis direction, and a flat, rectangular top wall portion forming a top surface 140 at its end in the positive Z-axis direction. A gas exhaust valve 800 is provided in the lid 170 at portions corresponding to the first bottom side surface 115 and the second bottom side surface 125.

[0056] With this configuration, the container 100 is configured such that the electrode assembly 700 and the like are housed inside the container body 160, and then the container body 160 and the lid 170 are joined by welding or the like, thereby sealing the interior. The material of the container 100 (container body 160 and lid 170) is not particularly limited, but is preferably a weldable metal such as stainless steel, aluminum, an aluminum alloy, iron, or plated steel sheet.

[0057] Although not shown, a liquid injection portion is formed on the lid 170. The liquid injection portion is a portion for injecting an electrolyte into the container 100 when the energy storage element 10 is manufactured.

[0058] The terminals 300 are terminals (positive electrode terminal 310 and negative electrode terminal 320) electrically connected to the electrode assembly 700 via the current collector 600. In other words, the terminals 300 are metal members that draw out electricity stored in the electrode assembly 700 to the external space of the energy storage element 10 and introduce electricity into the internal space of the energy storage element 10 to store electricity in the electrode assembly 700. The material of the terminals 300 is not particularly limited, and the terminals 300 (positive electrode terminal 310 and negative electrode terminal 320) are formed, for example, from a conductive material such as aluminum, an aluminum alloy, copper, or a copper alloy. The terminals 300 are connected (joined) to the current collector 600 by crimping, welding, or the like, and are attached to the lid 170.

[0059] In the present embodiment, the terminal 300 has a terminal body 330 and a shaft 340 protruding from the terminal body 330. The terminal body 330 is a portion that protrudes outward from the terminal installation surface of the container 100. Here, the terminal installation surface is the first upper surface 112 or the second upper surface 122. On either terminal installation surface, the terminal body 330 protrudes outward from the container 100 along the Z-axis direction. Through holes 112a, 122a through which the shaft 340 penetrates are formed in the lid 170 at locations corresponding to each terminal installation surface. The shaft 340 is connected (joined) to the current collector 600 by being crimped while penetrating the terminal installation surface, the external gasket 400, the internal gasket 500, and the current collector 600.

[0060] The current collectors 600 are arranged one on each side of the electrode body 700 in the X-axis direction, connected (joined) to the electrode body 700 and the terminal 300, and are conductive current collecting members (positive electrode current collector 610 and negative electrode current collector 620) that electrically connect the electrode body 700 and the terminal 300. Specifically, the current collector 600 integrally includes a first joint portion 630 that is connected (joined) to a tab portion 720 of the electrode body 700 (described later) by welding, crimping, or the like, and a second joint portion 640 that is connected (joined) to the terminal 300 by crimping, welding, or the like, as described above. The first joint portion 630 and the second joint portion 640 are each flat plate-shaped portions formed by bending a single piece of sheet metal. The material of the current collector 600 is not particularly limited, but for example, the positive electrode current collector 610 is formed of a conductive material such as aluminum or an aluminum alloy, similar to the positive electrode current collector foil 741 of the electrode body 700 described later, and the negative electrode current collector 620 is formed of a conductive material such as copper or a copper alloy, similar to the negative electrode current collector foil 751 of the electrode body 700 described later.

[0061] The outer gasket 400 is a plate-shaped, rectangular insulating sealing member that is disposed between the lid 170 of the container 100 and the terminal 300, and provides insulation and a seal between the lid 170 and the terminal 300. The inner gasket 500 is a plate-shaped, rectangular insulating sealing member that is disposed between the lid 170 and the current collector 600, and provides insulation and a seal between the lid 170 and the current collector 600. The external gasket 400 and the internal gasket 500 are formed from an electrically insulating resin such as polypropylene (PP), polyethylene (PE), polystyrene (PS), polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyether ether ketone (PEEK), tetrafluoroethylene perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyethersulfone (PES), ABS resin, or a composite material obtained by adding a filler to any of these resins.

[0062] The electrode body 700 is an electricity storage element (power generating element) formed by winding electrode plates and capable of storing electricity. The electrode body 700 has an elongated shape extending in the X-axis direction and an oval shape when viewed from the X-axis direction. The electrode body 700 has a shape in which the length in the X-axis direction is, for example, 300 mm or more, specifically, approximately 500 mm to 1500 mm. Therefore, the length in the X-axis direction of the electrode body 700 is longer than the length in the Z-axis direction. For example, the length in the X-axis direction of the electrode body 700 is three or more times the length in the Z-axis direction. The electrode body 700 has a main body portion 710 and multiple tab portions 720 protruding from the main body portion 710. As described above, the tab portions 720 are connected (joined) to the current collector 600. The tab portions 720 are an example of a connection portion connected to the current collector 600.

[0063] Specifically, the multiple tab portions 720 protrude one from each of both end faces in the X-axis direction of the main body portion 710. For example, a positive electrode tab portion 721 is provided on one end face of the main body portion 710 in the positive X-axis direction, and a negative electrode tab portion 722 is provided on the other end face of the main body portion 710 in the negative X-axis direction.

[0064] [Electrode Assembly] Fig. 5 is a perspective view showing the configuration of an electrode assembly 700 according to an embodiment. Specifically, Fig. 5 shows the configuration in a partially developed state in which the wound state of the electrode plates in the electrode assembly 700 is shown. As shown in Fig. 5, the electrode assembly 700 has a positive electrode plate 740, a negative electrode plate 750, and separators 761 and 762.

[0065] The positive electrode plate 740 is an electrode plate in which a positive electrode active material layer 742 is disposed on both sides of a positive electrode current collector foil 741, which is a long strip of metal foil. Aluminum, an aluminum alloy, or the like is used for the positive electrode current collector foil 741. The negative electrode plate 750 is an electrode plate in which a negative electrode active material layer 752 is disposed on both sides of a negative electrode current collector foil 751, which is a long strip of metal foil. Copper, a copper alloy, or the like is used for the negative electrode current collector foil 751. As the positive electrode active material used in the positive electrode active material layer 742 and the negative electrode active material used in the negative electrode active material layer 752, any known material can be used as long as it is capable of absorbing and releasing charge transport ions.

[0066] As a positive electrode active material, LiMPO ４ , LiMSiO ４ , LiMBO ３ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), polyanion compounds such as lithium titanate, LiMn ２ O ４ and LiMn １．５ Ni ０．５ O ４ Spinel-type lithium manganese oxides such as α-NaFeO ２ LiMO having a type crystal structure ２ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.) can be used. Examples of the negative electrode active material include lithium metal, alloys capable of absorbing and releasing lithium, carbon materials (graphite, non-graphitizable carbon, easily graphitizable carbon, low-temperature fired carbon, amorphous carbon, etc.), and silicon oxides.

[0067] Separators 761 and 762 are microporous sheets made of resin. Any known material can be used as the material for separators 761 and 762 as long as it does not impair the performance of energy storage element 10. Separators 761 and 762 may be made of a woven fabric or nonwoven fabric that is insoluble in organic solvents, a synthetic resin microporous film made of a polyolefin resin such as polyethylene, or the like.

[0068] The electrode assembly 700 is formed by winding a positive electrode plate 740, a negative electrode plate 750, and separators 761 and 762. The electrode assembly 700 is formed by stacking and winding the negative electrode plate 750, the separator 761, the positive electrode plate 740, and the separator 762 in this order. In this embodiment, the positive electrode plate 740, the negative electrode plate 750, and the separators 761 and 762 are wound around a winding axis L extending in the X-axis direction, thereby forming the wound electrode assembly 700. The winding axis L is an imaginary axis that serves as the central axis when winding the positive electrode plate 740, the negative electrode plate 750, and the separators 761 and 762. In this embodiment, the winding axis is a straight line that passes through the center of the electrode assembly 700 and is parallel to the X-axis direction.

[0069] A plurality of protruding pieces 743 protruding outward are arranged at intervals on the edge of the positive electrode plate 740 in the X-axis positive direction. Similarly, a plurality of protruding pieces 753 protruding outward are arranged at intervals on the edge of the negative electrode plate 750 in the X-axis negative direction. Each of the plurality of protruding pieces 743 is a portion where no positive electrode active material layer is disposed and the positive electrode current collector foil 741 is exposed (a portion where no positive electrode active material layer is formed). Each of the plurality of protruding pieces 753 is a portion where no negative electrode active material layer is disposed and the negative electrode current collector foil 751 is exposed (a portion where no negative electrode active material layer is formed). In FIG. 5 , the active material layer-free portions (a portion where no positive electrode active material layer is formed, a portion where no negative electrode active material layer is formed) are indicated by diagonal lines.

[0070] When the positive electrode plate 740, the negative electrode plate 750, and the separators 761, 762 are wound, the multiple protruding pieces 743 of the positive electrode plate 740 substantially overlap at the end face (one end face) of the main body 710 in the positive direction of the X axis, and the multiple protruding pieces 753 of the negative electrode plate 750 substantially overlap at the end face (the other end face) in the negative direction of the X axis. The portion of the positive electrode plate 740 where the multiple protruding pieces 743 overlap is the positive electrode tab portion 721. In other words, the positive electrode tab portion 721 is a portion where the multiple pieces (protruding pieces 743) of the electrode plates of the same polarity (positive electrode plate 740) among the multiple electrode plates (positive electrode plate 740 and negative electrode plate 750) are stacked.

[0071] Similarly, the portion of the negative electrode plate 750 where the multiple protruding pieces 753 overlap is the negative electrode tab portion 722. In other words, the negative electrode tab portion 722 is a portion where the multiple pieces (protruding pieces 753) provided on the electrode plate of the same polarity (negative electrode plate 750) among the multiple electrode plates (positive electrode plate 740 and negative electrode plate 750) are stacked.

[0072] As described above, the electrode body 700 includes a main body portion 710 that constitutes the main body of the electrode body 700, and tab portions 720 (positive electrode tab portion 721 and negative electrode tab portion 722) that protrude from each end face in the X-axis direction of the main body portion 710. In other words, the electrode body 700 includes a pair of tab portions that are composed of the positive electrode tab portion 721 and the negative electrode tab portion 722.

[0073] The main body portion 710 is an elongated cylindrical portion formed by winding together a portion of the positive electrode plate 740 where the positive electrode active material layer 742 is disposed (formed, coated), a portion of the negative electrode plate 750 where the negative electrode active material layer 752 is disposed (formed, coated), and separators 761, 762. The region of the main body portion 710 where at least one of the positive electrode active material layer 742 and the negative electrode active material layer 752 is laminated is referred to as the active material layer formation portion. The outer surface of the main body portion 710 has curved portions 711 at both ends in the Z-axis direction and flat portions 712 at both ends in the Y-axis direction.

[0074] The curved portion 711 is a portion that extends in the X-axis direction and protrudes in a curved shape in the Z-axis direction. When viewed in the X-axis direction, the curved portion 711 is curved in a semicircular arc shape. The flat portion 712 is a flat portion that extends in the X-axis direction and is parallel to the XZ plane, connecting the ends of the pair of curved portions 711. In the flat portion 712, multiple wound electrode plates and separators (positive electrode plate 740, negative electrode plate 750, separators 761, 762) are stacked in the Y-axis direction.

[0075] The shape of the electrode body is not limited to a wound type, but may be a stack type in which flat electrode plates are stacked, or a shape in which the electrode plates and / or separators are folded in an accordion-like manner (a form in which the separator is folded in an accordion-like manner to sandwich a rectangular electrode plate, a form in which the electrode plate and separator are stacked and then folded in an accordion-like manner, etc.).

[0076] [Spacer] Next, the specific shape of the spacer 20 will be described. Here, an intermediate spacer 21 will be described as an example of the spacer 20. The end spacer 22 differs in that the surface opposite the energy storage element 10 is formed as a flat surface overall, but the shape of the portion facing the energy storage element 10 is the same as that of the intermediate spacer 21, and therefore a description thereof will be omitted.

[0077] FIG. 6 is a perspective view showing an intermediate spacer 21 according to an embodiment. As shown in FIG. 6, the intermediate spacer 21 integrally includes a spacer main body 230 and a plurality of (four in this embodiment) spacer protrusions 240. The spacer main body 230 is a flat plate-shaped portion that overlaps the long side surface 130 of the container 100 when viewed from the Y-axis direction. Specifically, when viewed from the Y-axis direction, the spacer main body 230 has a shape based on a rectangle that is elongated in the X-axis direction, and spacer recesses 211 are formed at each corner of the rectangle. The spacer main body 230 has a shape that corresponds to the long side surface 130 and overlaps the entire long side surface 130. The spacer main body 230 is housed in the case 2 while being sandwiched between two energy storage elements 10 (see FIG. 3).

[0078] A spacer convex portion 240 is provided in each spacer concave portion 211. When viewed from the X-axis direction, the spacer convex portion 240 is a portion that protrudes in the Y-axis direction from both surfaces of the spacer main body 230 in the Y-axis direction. Of the four spacer convex portions 240, the two spacer convex portions 240 arranged on the upper part of the spacer main body 230 are upper spacer convex portions 250, and the two spacer convex portions 240 arranged on the lower part of the spacer main body 230 are lower spacer convex portions 260.

[0079] The two upper spacer protrusions 250 are symmetrical with respect to the YZ plane. Similarly, the two lower spacer protrusions 260 are symmetrical with respect to the YZ plane. Therefore, here, the upper spacer protrusions 250 and the lower spacer protrusions 260 in the positive direction of the X axis will be described, and a description of the upper spacer protrusions 250 and the lower spacer protrusions 260 in the negative direction of the X axis will be omitted.

[0080] Fig. 7 is an enlarged plan view showing an end portion of the intermediate spacer 21 in the positive direction of the X-axis according to the embodiment. Fig. 8 is an explanatory diagram showing the positional relationship at the end portion in the positive direction of the X-axis among the intermediate spacer 21, the energy storage device 10, and the case 2 in the embodiment. Fig. 8 shows the energy storage device 10 in a plan view, and the upper spacer convex portion 250 and the lower spacer convex portion 260 of the intermediate spacer 21 and the case 2 in a cross-sectional view.

[0081] 6 to 8, the upper spacer protrusion 250 is formed in an L-shape having a flat first portion 251 that extends along the YZ plane and a flat second portion 252 that extends along the XY plane. When viewed from the X-axis direction, the spacer main body 230 is disposed in the middle in the Y-axis direction between the first portion 251 and the second portion 252.

[0082] The first portion 251 is provided along sides of the spacer recess 211 extending in the positive X-axis direction and the positive Z-axis direction in the Z-axis direction. Therefore, the first portion 251 is disposed along the first upper side surface 111 (an example of a first surface) of the first recess 101 of the first side surface portion 110, and is in contact with the first upper side surface 111. The surface of the first portion 251 in the negative X-axis direction is an opposing surface that faces the first upper side surface 111. A hemispherical protrusion 253 is formed on this opposing surface.

[0083] The second portion 252 is provided along the sides of the spacer recess 211 extending in the X-axis direction in the positive X-axis and Z-axis directions. Therefore, the second portion 252 is disposed along the first upper surface 112 (an example of the second surface) of the first recess 101 of the first side surface portion 110 and is in contact with the first upper surface 112. Rectangular openings 255 that expose the terminals 300 are formed at both ends of the second portion 252 in the Y-axis direction. The openings 255 may have any shape as long as they expose the entire terminals 300, but a shape that fits into the outer gasket 400 is preferred because it provides better positioning.

[0084] The lower spacer protrusion 260 is formed in an L-shape having a flat first portion 261 extending along the YZ plane and a flat second portion 262 extending along the XY plane. When viewed from the X-axis direction, the spacer main body 230 is disposed in the middle in the Y-axis direction between the first portion 261 and the second portion 262.

[0085] The first portion 261 is provided along sides of the spacer recess 211 extending in the Z-axis direction in the positive X-axis direction and the negative Z-axis direction. Therefore, the first portion 261 is disposed along the first lower side surface 115 (an example of a first surface) of the second recess 102 of the first side surface portion 110, and is in contact with the first lower side surface 115. Semicircular openings 265 that expose the gas release valve 800 are formed at both ends of the first portion 261 in the Y-axis direction. The openings 265 may have any shape as long as the entire gas release valve 800 is exposed.

[0086] The second portion 262 is provided along sides of the spacer recess 211 extending in the X-axis direction in the positive X-axis direction and the negative Z-axis direction. Therefore, the second portion 262 is disposed along the first lower surface 114 (an example of a second surface) of the second recess 102 of the first side surface portion 110, and is in contact with the first lower surface 114. The upper surface of the second portion 262 is an opposing surface that faces the first lower surface 114. A hemispherical protrusion 263 is formed on this opposing surface.

[0087] [Positional Relationship of Energy Storage Element, Intermediate Spacer, and Case] ​​The state in which the energy storage element 10 and intermediate spacer 21 are housed in the case 2 will be described with reference to FIG. 8 . In this state, the upper spacer convex portion 250 is disposed within the first recess 101 of the first side surface portion 110 of the energy storage element 10 when viewed from the Y-axis direction. Specifically, the upper spacer convex portion 250 is contained within the first recess 101 of the first side surface portion 110 when viewed from the Y-axis direction. The two intermediate spacers 21 sandwiching the energy storage element 10 cover the entire inner wall surface (first upper side surface 111 and first top surface 112) of the first recess 101, with each upper spacer convex portion 250 exposing the terminal 300 and the external gasket 400. This improves insulation around the terminal 300.

[0088] On the other hand, when viewed from the Y-axis direction, the lower spacer convex portion 260 is disposed within the second recess 102 of the first side surface portion 110 of the energy storage device 10. Specifically, when viewed from the Y-axis direction, the lower spacer convex portion 260 is contained within the second recess 102 of the first side surface portion 110. The two intermediate spacers 21 sandwiching the energy storage device 10 cover most of the inner wall surface (first lower side surface 115 and first lower surface 114) of the second recess 102, with each lower spacer convex portion 260 exposing the gas release valve 800.

[0089] In this state, the top surface 140, bottom surface 150, first middle side surface 113, and second middle side surface 123 of the energy storage device 10 are entirely exposed from the intermediate spacer 21. As described above, when viewed from the Y-axis direction, the upper spacer protrusion 250 is fitted within the first recess 101 of the first side surface portion 110, and the lower spacer protrusion 260 is fitted within the second recess 102 of the first side surface portion 110. As a result, the upper spacer protrusion 250 and the lower spacer protrusion 260 do not interfere with the case 2, so that the top surface 140, bottom surface 150, first middle side surface 113, and second middle side surface 123 are entirely in contact with the inner surface of the case 2. Specifically, the top surface 140 is in contact with the lower surface of the case lid 40. The bottom surface 150 is in contact with the upper surface of the bottom wall 32 of the case main body 30. The first middle side surface 113 and second middle side surface 123 are in contact with a pair of inner surfaces of the side wall 33 that face each other in the X-axis direction. In this manner, the top surface 140, the bottom surface 150, the first inner side surface 113, and the second inner side surface 123 of the energy storage element 10 are in contact with the inner surface of the case 2, and therefore the energy storage element 10 is cooled by the refrigerant pipe 950 via the case 2. In other words, the case 2 and the refrigerant pipe 950 are an example of a cooling unit that cools the energy storage element 10.

[0090] In particular, in this state, the protrusion 253 is crushed by contact with the first upper side surface 111 and compression. This compression may completely crush the protrusion 253 so that it becomes flat, or may crush the protrusion 253 so that part of the protrusion 253 remains. After compression, the protrusion 253 becomes a protrusion mark 254 (shown by a dashed line in FIG. 8 ) that is crushed more than its original shape. The protrusion mark 254 (protrusion 253) attempts to elastically return to its original shape, and the restoring force of this protrusion mark 254 pushes the energy storage element 10 in the X-axis direction, thereby positioning the energy storage element 10 in the X-axis direction. Furthermore, this restoring force presses the first middle side surface 113 and the second middle side surface 123 of the energy storage element 10 against a pair of inner surfaces of the side wall 33 that face each other in the X-axis direction, thereby improving contact.

[0091] On the other hand, the protrusions 263 are also crushed by contacting and compressing the first lower surface 114. This compression may completely crush the protrusions 263 so that they are flat, or may crush them so that only a portion of the protrusions 263 remains. After being crushed, the protrusions 263 become protrusion marks 264 (shown by dashed lines in FIG. 8 ) that are crushed further than their original shape. The protrusion marks 264 (protrusions 263) attempt to elastically return to their original shape, and the restoring force of this force presses the energy storage element 10 in the Z-axis direction, thereby positioning the energy storage element 10 in the Z-axis direction. Furthermore, this restoring force presses the top surface 140 and bottom surface 150 of the energy storage element 10 against the lower surface of the case lid 40 and the upper surface of the bottom wall 32, thereby improving contact.

[0092] In this way, the protrusion marks 254, 264 improve the contact between the container 100 of the energy storage element 10 and the case 2, thereby improving the cooling performance of the energy storage element 10. Note that in this embodiment, a hemispherical shape is exemplified as the shape of the protrusions 253, 263, but the shape of the protrusions may be any shape as long as they can be crushed by compression.

[0093] [Explanation of Effects] As described above, according to the energy storage device 1 according to the embodiment, when viewed from the arrangement direction (Y-axis direction), the spacer convex portions (upper spacer convex portion 250, lower spacer convex portion 260) arranged in the recesses (first recess 101, second recess 102) are positioned in a direction intersecting the arrangement direction from the spacer main body 230 and extend in the arrangement direction. Therefore, the spacer convex portions interfere with the inner wall surfaces of the recesses, thereby enabling the positioning of the energy storage elements 10. In this case, when viewed from the arrangement direction, the spacer convex portions are arranged within the recesses. In other words, the energy storage elements 10 can be positioned even if the spacer convex portions are arranged so as not to protrude outside the recesses. The spacer convex portions do not get in the way of the outer surface of the container 100 where the spacer convex portions do not protrude outside the recesses, making it easy for the cooling unit (case 2) to come into contact with the outer surface. Therefore, the cooling efficiency for the energy storage elements 10 can be improved.

[0094] Because the terminal 300 is disposed in the first recess 101, the upper spacer protrusion 250 and the terminal 300 can be accommodated in the first recess 101, thereby preventing the space outside the energy storage device 10 from being consumed. On the other hand, because the gas exhaust valve 800 is disposed in the second recess 102, the lower spacer protrusion 260 and the exhaust flow path (third space S3 and fourth space S4) can be accommodated in the second recess 102, thereby preventing the space outside the energy storage device 10 from being consumed.

[0095] The upper spacer protrusion 250 has openings 255 formed therein for exposing the terminals 300, so that the openings 255 can prevent interference between the upper spacer protrusion 250 and the terminals 300, allowing for smooth assembly.

[0096] The lower spacer protrusion 260 is formed with an opening 265 that exposes the gas exhaust valve 800, which prevents interference between the lower spacer protrusion 260 and the gas exhaust valve 800, allowing for smooth assembly. Furthermore, the gas from the gas exhaust valve 800 passes through the opening 265, allowing for smooth gas exhaust.

[0097] By forming the upper spacer convex portion 250 in an L-shape, a first portion 251 of the upper spacer convex portion 250 is aligned along the first upper side surface 111 of the first recess 101, and a second portion 252 is aligned along the first top surface 112 of the first recess 101. As a result, most of the inner wall surface of the first recess 101 is covered with the upper spacer convex portion 250, and therefore, the upper spacer convex portion 250 can suppress short circuits that may occur when, for example, a bus bar is placed in the first recess 101.

[0098] During the manufacture of the energy storage device 1, the protrusions 253, 263 formed on the upper spacer protrusions 250 and the lower spacer protrusions 260 are crushed by the inner wall surfaces of the first recess 101 and the second recess 102, leaving protrusion marks 254, 264. By crushing these protrusions 253, 263, the energy storage elements 10 positioned by the upper spacer protrusions 250 and the lower spacer protrusions 260 can be pressed against the case 2 (cooling section). This improves contact between the energy storage elements 10 and the case 2, enabling more efficient cooling.

[0099] Even in the energy storage device 1 including a plurality of energy storage elements 10 and a plurality of spacers 20 sandwiching the energy storage elements 10, the cooling efficiency for each energy storage element 10 can be improved.

[0100] [Explanation of Modifications] Modifications of the above embodiment will be described below. In the following description, parts that are the same as those in the above embodiment or other modifications will be given the same reference numerals, and their description may be omitted. In the following description, the end in the positive direction of the X axis will be used as an example, but the same applies to the end in the negative direction of the X axis.

[0101] (Variant 1) In the above embodiment, an upper spacer convex portion 250 and a lower spacer convex portion 260 that are L-shaped when viewed from the Y-axis direction are exemplified, but in variant 1, an upper spacer convex portion 250a and a lower spacer convex portion 260a that are linear when viewed from the Y-axis direction are described.

[0102] FIG. 9 is an explanatory diagram showing the positional relationship between the intermediate spacer 21a, the energy storage device 10, and the case 2 according to Modification 1. FIG. 9 is a diagram corresponding to FIG. 8. As shown in FIG. 9, the upper spacer convex portion 250a of the intermediate spacer 21a has a first portion 251a along the YZ plane, and does not have a second portion. As a result, the upper spacer convex portion 250a is formed in a straight line when viewed from the Y-axis direction. The first portion 251a is in contact with the first upper side surface 111 of the container 100. The lower end of the first portion 251a is in contact with the first upper surface 112. As a result, the first portion 251a positions the container 100 in the X-axis and Z-axis directions.

[0103] The lower spacer protrusion 260a of the intermediate spacer 21a has a second portion 262a that follows the XY plane, but does not have a first portion. As a result, the lower spacer protrusion 260a is formed in a straight line when viewed from the Y-axis direction. The second portion 262a contacts the first lower surface 114 of the container 100. The end of the second portion 262a in the negative X-axis direction contacts the first lower side surface 115. As a result, the second portion 262a positions the container 100 in the X-axis and Z-axis directions.

[0104] (Modification 2) In Modification 2, an upper spacer protrusion 250b and a lower spacer protrusion 260b that are dot-shaped when viewed from the Y-axis direction will be described.

[0105] Fig. 10 is an explanatory diagram showing the positional relationship between the intermediate spacer 21b, the energy storage device 10, and the case 2 according to Modification 2. Fig. 10 is a diagram corresponding to Fig. 8. As shown in Fig. 10, the upper spacer convex portion 250b of the intermediate spacer 21b is a shaft-shaped portion extending in the Y-axis direction and located at the corner of the first recess 101 (the corner between the first upper side surface 111 and the first top surface 112). As a result, the upper spacer convex portion 250b is formed in a dot shape when viewed from the Y-axis direction. The upper spacer convex portion 250b is in contact with the first upper side surface 111 and the first top surface 112, and therefore positions the container 100 in the X-axis and Z-axis directions.

[0106] The lower spacer protrusion 260b of the intermediate spacer 21b is a shaft-shaped portion extending in the Y-axis direction and located at a corner of the second recess 102 (the corner between the first lower side surface 115 and the first lower surface 114). As a result, the lower spacer protrusion 260b is formed in a point shape when viewed from the Y-axis direction. The lower spacer protrusion 260b is in contact with the first lower side surface 115 and the first lower surface 114, and therefore positions the container 100 in the X-axis and Z-axis directions.

[0107] (Modification 3) In Modification 3, a spacer having a connecting portion that connects adjacent spacers will be described. Here, the middle spacer 21c will be described as an example, but the same applies to end spacers.

[0108] FIG. 11 is a perspective view showing an intermediate spacer 21c having a connecting portion according to Modification 3. The upper spacer protrusion 250c of the intermediate spacer 21c has a connecting portion 270c provided on a first portion 251c. Specifically, a concave connecting recess 271c, which is part of the connecting portion 270c, is provided at the end of the first portion 251c facing in the positive direction of the Y axis. Meanwhile, a convex connecting protrusion 272c, which is part of the connecting portion 270c, is provided at the end of the first portion 251c facing in the negative direction of the Y axis. The connecting protrusion 272c has a shape corresponding to the connecting recess 271c. As a result, of a pair of adjacent intermediate spacers 21c, the connecting recess 271c of one intermediate spacer 21c can be fitted with the connecting protrusion 272c of the other intermediate spacer 21c. After fitting, the pair of adjacent intermediate spacers 21c are connected to each other. This connection ensures stable assembly of the pair of intermediate spacers 21c, and also ensures stable positioning of the energy storage device 10 between them. The connecting portion may be provided on the lower spacer protrusion.

[0109] (Variation 4) In the above embodiment, an energy storage element 10 based on a flat rectangular parallelepiped shape (approximately rectangular parallelepiped shape) has been exemplified, but the shape of the energy storage element, i.e., the shape of the container is not limited to a shape based on a rectangular parallelepiped shape, and may be a shape based on a polygonal prism shape other than a rectangular parallelepiped, an elongated cylindrical shape, an elliptical cylindrical shape, a cylindrical shape, etc. In Variation 4, an energy storage element including a container based on an elongated cylindrical shape will be described.

[0110] Fig. 12 is a perspective view showing an energy storage device 10d according to Modification 4. As shown in Fig. 12, a container 100d of the energy storage device 10d has a top surface 140d formed as a curved surface that protrudes in the positive direction of the Z axis, and a bottom surface 150d formed as a curved surface that protrudes in the negative direction of the Z axis, when viewed from the X axis direction.

[0111] (Variation 5) In the above embodiment, a case in which the refrigerant pipe 950 is exposed has been described. However, in Variation 5, a case in which the refrigerant pipe 950 is covered by a cover 951e will be described. Fig. 13 is an explanatory diagram showing the cover 951e according to Variation 5. As shown in Fig. 13, the bottom wall 32, the side wall 33, and the case lid 40 are provided with a cover 951e that covers the refrigerant pipe 950. The cover 951e covers the refrigerant pipe 950, and the portion of the cover 951e that does not correspond to the refrigerant pipe 950 is in contact with the bottom wall 32, the side wall 33, and the case lid 40. The cover 951e is preferably made of metal from the standpoint of heat dissipation, but may also be made of resin.

[0112] (Variation 6) In the above embodiment, the refrigerant pipe 950 is provided on the outer surface of the case 2. However, in Variation 6, the refrigerant pipe 950 is embedded in the bottom wall 32f, the side wall 33f, and the case lid 40f. FIG. 14 is an explanatory diagram showing the bottom wall 32f, the side wall 33f, and the case lid 40f according to Variation 6. As shown in FIG. 14, the refrigerant pipe 950 is embedded in the bottom wall 32f, the side wall 33f, and the case lid 40f. Since the refrigerant pipe 950 is embedded in the bottom wall 32f, the side wall 33f, and the case lid 40f in this manner, a simple appearance can be achieved. The refrigerant pipe 950 may be embedded in at least one of the bottom wall 32f, the side wall 33f, and the case lid 40f.

[0113] (Other Modifications) Although the energy storage element according to the embodiment of the present invention (including its modifications, the same applies hereinafter) has been described above, the present invention is not limited to the above-described embodiment. The embodiment disclosed herein is illustrative in all respects, and the scope of the present invention includes all modifications within the meaning and scope of the claims.

[0114] For example, in the above embodiment, the case where only one electrode body 700 is housed in the container 100 has been exemplified, but a plurality of electrode bodies may be housed in the container.

[0115] In the above embodiment, the case 2 and the refrigerant pipe 950 are shown as an example of a cooling unit. However, the cooling unit may be in any form as long as it cools the energy storage elements 10 via the outer surface of the container 100. For example, the cooling unit may be a cooling plate that is housed together with the energy storage elements 10 in the case 2 and that contacts the outer surface of the container 100. In addition, even if the case does not have a refrigerant pipe, the heat of the energy storage elements 10 is released from the case to the outside, so the case can also be used as the cooling unit.

[0116] In the above embodiment, the case where the upper spacer convex portion 250 is arranged to fit into the first recess 101 and the lower spacer convex portion 260 is arranged to fit into the second recess 102 as viewed in the Y-axis direction has been exemplified. However, the upper spacer convex portion 250 may protrude from the first recess 101 and the lower spacer convex portion 260 may protrude from the second recess 102 as viewed in the Y-axis direction. For example, when a cooling unit is to be in contact with the top surface 140 and the bottom surface 150 of the container 100, the second portion 252 of the upper spacer convex portion 250 may protrude from the first recess 101 in the X-axis direction and the second portion 262 of the lower spacer convex portion 260 may protrude from the second recess 102 in the X-axis direction. When the cooling portion is brought into contact with the first middle side surface 113, the second middle side surface 123, and the top surface 140 of the container 100, the first part 251 of the upper spacer convex portion 250 may be made to protrude in the Z-axis direction from the first recess 101, and the first part 261 of the lower spacer convex portion 260 may be made to protrude in the Z-axis direction from the second recess 102.

[0117] In this way, if there is an outer surface of the container (top surface 140, bottom surface 150, first inner side surface 113, and second inner side surface 123) that does not come into contact with the cooling unit, a portion of the spacer 20 may protrude so as to overlap that outer surface. However, it is preferable that most of the outer surface (for example, in the case of the top surface 140, ¾ or more of the total area of ​​the top surface 140) is exposed from a portion of the spacer 20. The cooling unit may come into contact with the outer surface that is exposed from a portion of the spacer 20.

[0118] In the above embodiment, an example is given of a storage element 10 in which terminals 300 are arranged only in the first recess 101, but the storage element may also be one in which terminals 300 are arranged only in the second recess, or one in which terminals 300 are arranged in both the first recess and the second recess.

[0119] Any combination of the components included in the above-described embodiments and their modifications is also included within the scope of the present invention.

[0120] The present invention can be applied to an electricity storage device including an electricity storage element such as a lithium ion secondary battery.

[0121] REFERENCE SIGNS LIST 1 Energy storage device 2 Case 10, 10d Energy storage element 20 Spacer 21, 21a, 21b, 21c Intermediate spacer 22 End spacer 30 Case body 40 Case lid 100, 100d Container 101 First recess (recess) 102 Second recess (recess) 211 Spacer recess 230 Spacer body 240 Spacer protrusion 250, 250a, 250b, 250c Upper spacer protrusion 251, 251a, 251c, 261 First part 252, 262, 262a Second part 253, 263 Protrusion 254, 264 Protrusion mark 255, 265 Opening 260, 260a, 260b Lower spacer protrusion 300 Terminal 400 External gasket 500 Internal gasket 600 Current collector 700 Electrode body 710 Main body 720 Tab portion 800 Gas discharge valve 950 Refrigerant pipe

Claims

1. An energy storage device comprising: an energy storage element; and a spacer arranged adjacent to the energy storage element, wherein the energy storage element comprises a container for accommodating an electrode body, the container having at least two recesses penetrating in the alignment direction of the energy storage element and the spacer, the spacer comprising: a spacer main body that overlaps the container when viewed from the alignment direction; and a spacer protrusion that extends from the spacer main body in the alignment direction and is arranged within the recesses when viewed from the alignment direction, wherein the spacer protrusion positions the energy storage element and the spacer.

2. The electricity storage device according to claim 1, wherein the electricity storage element has at least one of a terminal and a gas release valve disposed within the recess.

3. The electricity storage device according to claim 2, wherein the spacer protrusion has an opening through which at least one of the terminal and the gas release valve is exposed.

4. The energy storage device according to any one of claims 1 to 3, wherein the inner wall surface of the recess has a first surface and a second surface extending in different directions when viewed from the arrangement direction, and the spacer protrusion is formed in an L-shape having a first portion that extends along the first surface and a second portion that extends along the second surface.

5. The energy storage device according to any one of claims 1 to 3, wherein a surface of the spacer protrusion that faces the inner wall surface of the recess is formed with a protrusion mark that has been crushed by the inner wall surface of the recess.

6. The energy storage device according to any one of claims 1 to 3, comprising: a plurality of the energy storage elements arranged in the arrangement direction; and a plurality of the spacers arranged in the arrangement direction and positioned to sandwich each of the plurality of energy storage elements.

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