Power storage device

Abstract

To provide a power storage device, in order to prevent occurrence of a short circuit or a ground fault, in which heat transfer properties are improved while substantially and electrically insulating between a current collector and a power storage element container, between a terminal and a power storage element container, and between a power storage element container and an exterior body.SOLUTION: A power storage device including a power storage element 10 and an exterior body that houses the power storage element includes an electrode body 700, a current collector 600 that is electrically connected to the electrode body, a container 100 that houses the electrode body and the current collector, and a terminal 300 that is provided on an outer surface of the container and is electrically connected to the current collector. At least one of a first heat transfer path 960 which thermally connects the electrode body or the current collector and the container and which is substantially electrically insulated by providing a heat transfer insulating member 900 in a path, and a second heat transfer path which thermally connects the container or the terminal and the exterior body and which is electrically insulated by providing the heat transfer insulating member in the path is provided.SELECTED DRAWING: Figure 6

Description

[Technical Field]

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

[0002] Conventionally, a battery pack is known that includes at least one battery cell, a housing having a bottom and side walls for accommodating the battery cell, and a cover that covers the battery cell and is connected to the top of the housing (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-249309 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, high-current charge / discharge performance has been required for on-board lithium-ion battery-based energy storage devices. It is known that during high-current charge / discharge, current concentrates on the battery's electrodes, current collectors, terminals, and even bus bars within the energy storage device, resulting in localized temperature increases. However, to date, no proactive efforts have been made to improve heat transfer characteristics to effectively cool the heat-generating parts, because of the tradeoff of the risk of short-circuiting and ground faults in the energy storage device.

[0005] The object of the present invention is to provide an energy storage device that has improved heat transfer while substantially providing electrical insulation between the collector and the energy storage element container, between the terminal and the energy storage element container, and between the energy storage element container and the outer casing so as to prevent the occurrence of short circuits or ground faults. [Means for solving the problem]

[0006] An energy storage device according to one embodiment of the present invention is an energy storage device comprising an energy storage element and an exterior body that houses the energy storage element, wherein the energy storage element comprises an electrode body, a current collector electrically connected to the electrode body, a container that houses the electrode body and the current collector, and a terminal that is installed on the outer surface of the container and electrically connected to the current collector, and comprises at least one of a first heat transfer path that thermally connects the current collector and the container while providing a heat transfer insulating member within the path, thereby substantially electrically insulating them, and a second heat transfer path that thermally connects the container or the terminal and the exterior body while providing a heat transfer insulating member within the path, thereby substantially electrically insulating them. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an electricity storage device that does not cause short circuits or ground faults and has improved heat transfer properties. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing the appearance of a power storage device according to an embodiment. [Figure 2] FIG. 2 is an exploded perspective view showing each component of the electricity storage device according to the embodiment. [Figure 3] FIG. 3 is a perspective view showing the appearance of the energy storage device according to the embodiment. [Figure 4] FIG. 4 is an exploded perspective view showing the components of the energy storage device according to the embodiment. [Figure 5] FIG. 5 is a perspective view showing the configuration of an electrode body according to the embodiment. [Figure 6] FIG. 6 is an explanatory view showing a positive electrode current collector and a heat transfer insulating member according to the embodiment. [Figure 7] FIG. 7 is an explanatory diagram showing a positive electrode current collector and a heat transfer insulating member according to the embodiment. [Figure 8] FIG. 8 is a partial cross-sectional view of the electricity storage device showing the second heat transfer path according to the embodiment. [Figure 9A]FIG. 9A is an explanatory diagram showing another connection configuration between the bus bar and the thermal insulating member according to the first modification. [Figure 9B] FIG. 9B is an explanatory diagram showing another connection configuration between the bus bar and the thermal insulating member according to the first modification. [Figure 9C] FIG. 9C is an explanatory diagram showing another connection configuration between the bus bar and the thermal insulating member according to the first modification. [Figure 10] FIG. 10 is a partial cross-sectional view of the electricity storage device showing the biasing portion according to the second modification. [Figure 11] FIG. 11 is a partial cross-sectional view of an energy storage device showing a heat transfer insulating member according to the third modification. [Figure 12] FIG. 12 is a partial cross-sectional view of an energy storage device showing a heat transfer insulating member according to the fourth modification. [Figure 13] FIG. 13 is a partial cross-sectional view of an electricity storage device showing a thermal insulating member according to the fifth modification. [Figure 14] FIG. 14 is a partial cross-sectional view showing a container according to the sixth modification. [Figure 15] FIG. 15 is a perspective view showing an electricity storage device according to the seventh modification. DETAILED DESCRIPTION OF THE INVENTION

[0009] (1) An energy storage device according to one aspect of the present invention is an energy storage device comprising an energy storage element and an exterior body that houses the energy storage element, wherein the energy storage element comprises an electrode body, a current collector electrically connected to the electrode body, a container that houses the electrode body and the current collector, and a terminal that is installed on the outer surface of the container and electrically connected to the current collector, and comprises at least one of a first heat transfer path that thermally connects the electrode body or the current collector to the container while being substantially electrically insulated by providing a heat transfer insulating member within the path, and a second heat transfer path that thermally connects the container or the terminal to the exterior body while being substantially electrically insulated by providing a heat transfer insulating member within the path.

[0010] According to the electricity storage device described in (1) above, the first heat transfer path and the second heat transfer path are provided with the heat transfer insulating members, so that it is possible to improve heat transfer while ensuring electrical insulation.

[0011] (2) The electricity storage device according to (1) above may include both a first heat transfer path and a second heat transfer path.

[0012] According to the electricity storage device described in (2) above, since both the first heat transfer path and the second heat transfer path are provided, heat generated in the electricity storage element can be efficiently transferred to the exterior body.

[0013] (3) In the electricity storage device described in (1) or (2) above, the thermally conductive insulating member may be an adhesive tape.

[0014] According to the energy storage device described in (3) above, by using an adhesive tape that has excellent thermal conductivity, electrical insulation, and workability as the heat transfer insulation member, it is possible to suppress an increase in thermal resistance in the first heat transfer path and the second heat transfer path.

[0015] (4) In the electricity storage device described in (3) above, the heat transfer insulating member may be disposed at a position facing a connection portion where the current collector and the electrode assembly are connected.

[0016] According to the electricity storage device described in (4) above, the heat transfer insulator is disposed at a position facing the connection portion of the current collector where the electrode assembly is connected, so that heat from the electrode assembly can be transferred to the container via the heat transfer insulator over a short distance and over a large area, thereby enabling efficient heat transfer.

[0017] (5) In the energy storage device described in any one of (1) to (4) above, a bus bar may be provided to electrically connect between terminals of the energy storage elements and at least one of between external terminals provided on the exterior body and between the terminals, and the second heat transfer path may be provided with the bus bar.

[0018] According to the energy storage device described in (5) above, the second heat transfer path includes a bus bar. Therefore, by bringing the bus bar into contact with the inner wall of the exterior body via a heat transfer insulating member, heat from the bus bar can be efficiently transferred.

[0019] (6) The electricity storage device according to any one of (1) to (5) above may further include a biasing portion that biases at least one of the second heat transfer path and the container toward the exterior body.

[0020] According to the electricity storage device described in (6) above, when the biasing unit biases the second heat transfer path toward the exterior body, contact between the second heat transfer path and the exterior body is improved, allowing heat to be stably transferred to the exterior body. On the other hand, when the biasing unit biases the container toward the exterior body, contact between the container and the exterior body is improved, allowing heat to be stably transferred to the exterior body.

[0021] (7) In the energy storage device described in any one of (1) to (6) above, the heat transfer insulator may be in contact with at least one of a pair of connection objects connected to the heat transfer insulator on multiple surfaces.

[0022] According to the electricity storage device described in (7) above, the heat transfer insulator is in contact with at least one of the pair of connection objects on multiple surfaces, so that the contact area can be increased, thereby improving heat transfer.

[0023] (8) In the electricity storage device according to any one of (1) to (7), the volume resistivity of the heat transfer insulating member is 1.0 × 10 when a direct current of 1500 V is applied. 12 It may also be specified that the resistance is Ω·m or more and the thermal conductivity is 1.0 W / m·K or more according to the ASTM D5470 method.

[0024] According to the energy storage device described in (8) above, when a heat transfer insulating member with this level of volume resistivity is used, it can be considered to be substantially electrically insulated, and good heat transfer properties can be ensured while ensuring the electrical insulation that is the object of the present invention.

[0025] (Embodiment) 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 reference numerals are used for identical or similar components. 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.

[0026] In the following description and drawings, the longitudinal direction of the energy storage element, or the direction along the winding axis of the electrode body provided in the energy storage element, is defined as the X-axis direction. The thickness direction of the container of the energy storage element is defined as the Y-axis direction. The direction in which the bottom surface of the container body and the top surface of the lid of the container are aligned, or the up-down direction, is defined as the Z-axis direction. These X-axis, Y-axis, and Z-axis directions intersect with each other (orthogonal in this embodiment). Note that, depending on the mode of use, the Z-axis may not be the up-down direction, but for ease of explanation, the following description will be made assuming that the Z-axis is the up-down direction. In the following description, when the term "insulation" is used, it means "electrical insulation." An insulating material has a volume resistivity of 1×10 10 Ωm or more is preferable, and 1×10 12 Ωm or more is preferable, and 1×10 14 More preferably, it is Ωm or more.

[0027] In the following description, the positive X-axis direction refers to the direction of the X-axis arrow, and the negative X-axis direction refers to the direction opposite 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. "Two directions are perpendicular" does not only mean that the two directions are completely perpendicular, but also means that the directions are substantially perpendicular, i.e., there is a difference of about a few percent.

[0028] [Explanation of the storage device] First, a schematic configuration of a power storage device 1 according to the present embodiment will be described. Fig. 1 is a perspective view showing the appearance of the power storage device 1 according to the embodiment. Fig. 2 is an exploded perspective view showing each component of the power storage device 1 according to the embodiment.

[0029] The power storage device 1 is a device that can charge with electricity from an external source and discharge electricity to the outside, and in this embodiment has a substantially rectangular parallelepiped shape. The power storage device 1 is used as a battery for driving or starting the engine of a moving object such as an automobile, a motorcycle, a personal watercraft, a ship, a snowmobile, an agricultural machine, a construction machine, an automatic guided vehicle (AGV), or a rolling stock for an electric railway. 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 rolling stock for an electric railway include an electric train, a monorail, a linear motor car, and a hybrid electric train equipped with both a diesel engine and an electric motor. The power storage device 1 may also be used as a stationary battery for home or business use.

[0030] As shown in Fig. 1, the energy storage device 1 includes an exterior housing 2. As shown in Fig. 2, the exterior housing 2 accommodates a plurality of energy storage elements 10, a plurality of spacers 20, a plurality of bus bars 50 (see Fig. 8), and the like. The energy storage device 1 also includes external terminals 11 (positive and negative external terminals) for electrically connecting to an external device. 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, a bus bar holder that holds the bus bars 50, a bus bar cover, a circuit board that monitors or controls the charged and discharged states of the energy storage elements 10, and electrical components such as a relay, a fuse, a shunt resistor, and a connector.

[0031] The exterior body 2 is a rectangular parallelepiped (box-shaped) container (module case) that constitutes the exterior body (housing, outer shell) of the energy storage device 1. A rectangular parallelepiped is a hexahedron with all faces formed of rectangles or squares. The exterior body 2 is disposed outside the energy storage elements 10 and the spacers 20, etc., and secures the energy storage elements 10 and the spacers 20 in predetermined positions to protect them from impacts and the like. The exterior body 2 is a metal exterior body formed of a metal member such as aluminum, aluminum alloy, stainless steel, iron, or plated steel sheet. The exterior body 2 may be formed of an insulating member such as any resin material that can be used for the spacers 20 described below. When the exterior body 2 is formed of a conductive material, the inner surface of the exterior body 2 may be coated with an insulating material to ensure insulation from the energy storage elements 10. From the viewpoint of heat transfer, the exterior body 2 is preferably formed of a metal member. In this manner, the exterior body 2 functions as a heat sink that receives heat transferred from the energy storage elements 10.

[0032] 2, the exterior body 2 includes an exterior body main body 30 that constitutes the main body of the exterior body 2, and an exterior body lid body 40 that constitutes the lid body of the exterior body 2. The exterior body main body 30 is a bottomed rectangular cylindrical housing (chassis) with an opening 31 formed in the positive direction of the Z axis, and houses a plurality of energy storage elements 10, a plurality of spacers 20, etc.

[0033] Specifically, the exterior body main 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 exterior body main body 30 in the negative Z-axis direction. The side wall 33 is a rectangular, annular wall extending from the outer periphery in the positive Z-axis direction 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 in 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 exterior body 2 and exhausts gas discharged from the energy storage device 10 to the outside of the exterior body 2.

[0034] The exterior body lid 40 is a flat rectangular member that closes the rectangular opening 31 of the exterior body main body 30. The exterior body main body 30 and the exterior body lid 40 are joined by welding, fusing, screwing, or the like to form a tight seal (sealed). The exterior body main body 30 and the exterior body lid 40 may be made of the same material or different materials. On the top surface of the exterior body lid 40, a pair of external terminals 11 are arranged side by side in the Y-axis direction at the end in the positive direction of the X-axis.

[0035] The energy storage element 10 is a secondary battery (single cell) that can charge and discharge electricity, and more specifically, is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. The energy storage element 10 is a non-pouch type battery. The energy storage element 10 is not limited to a non-aqueous electrolyte secondary battery, and may be a secondary battery other than a non-aqueous 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. Furthermore, the energy storage element 10 may be an all-solid-state lithium battery using a solid electrolyte, or a polymer lithium battery. Details of the energy storage element 10 will be described later.

[0036] The spacer 20 is a flat plate-like member that is arranged alongside the energy storage element 10 in the Y-axis direction and that insulates and / or heats the energy storage element 10 from other members. The spacer 20 is an insulating or 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 exterior body 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 these materials and a filler, or a heat-insulating material such as mica.

[0037] Of the spacers 20, the spacers 20 arranged between adjacent energy storage elements 10 are intermediate spacers, and the two spacers 20 arranged at the ends of the plurality of energy storage elements 10 in the Y-axis direction are end spacers. All of the spacers 20 may be formed of the same material, or some of the spacers 20 may be formed of different materials. When viewed from the Y-axis direction, the spacers 20 have a shape that corresponds to the outer shape of the containers 100 of the energy storage elements 10. In other words, the spacer 20 has a shape that corresponds to the outer shape of the containers 100 of the energy storage elements 10 in the X-axis direction, with rectangular cutouts 21 formed at the bottom of both ends in the X-axis direction in a rectangular parallelepiped that is elongated in the X-axis direction.

[0038] The busbar 50 (see FIG. 8 ) is connected (joined) to the terminals 300 of the multiple energy storage elements 10. Specifically, the multiple busbars 50 connect the terminals 300 of the multiple energy storage elements 10 to each other and electrically connect the terminals 300 of the end energy storage elements 10 to the external terminals 11. That is, one busbar 50 may connect the terminals 300 of the multiple energy storage elements 10 to each other, or may connect the terminals 300 to the external terminals 11. The connection configuration of the busbars 50 is not particularly limited. The multiple 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 busbar 50 and the terminals 300 are connected (joined) by welding or the like, but the connection configuration is not particularly limited. The busbar 50 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. Details of the busbar 50 will be described later.

[0039] [Energy storage element] Next, a schematic configuration of the energy storage device 10 according to the present embodiment will be described. Fig. 3 is a perspective view showing the appearance of the energy storage device 10 according to the embodiment. Fig. 4 is a perspective view showing each component when the energy storage device 10 according to the embodiment is disassembled.

[0040] The energy storage element 10 has a shape in which the length in the X-axis direction is longer than the Y-axis direction and the length in the X-axis direction is longer than the Z-axis direction. In particular, in this embodiment, the energy storage element 10 has a shape in which the length in the Z-axis direction is longer than the Y-axis direction. The energy storage element 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, an electrode assembly 700, and a heat transfer insulator 900 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, the current collectors 600, and the heat transfer insulator 900; the same applies below) are arranged on a first side surface portion 110 of the container 100 in the positive direction of the X-axis. In other words, the first side surface portion 110 is the range from the end face of the container 100 in the positive direction of the X-axis where the components of the positive electrode are arranged. The first side surface portion 110 is a portion within a range of 1% to 15% of the length of the container 100 in the X-axis direction from the end face of the container 100 in the positive X-axis direction.

[0041] The components of the negative electrode are disposed on the second side surface portion 120 in the negative X-axis direction of the container 100. In other words, 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. The second side surface portion 120 is a region in the X-axis direction that is within a range of 1% to 15% of the length of the container 100 from the end surface of the container 100 in the negative X-axis direction.

[0042] An electrolyte solution (nonaqueous 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.

[0043] Specifically, the container 100 has an outer shape based on a rectangular parallelepiped shape elongated 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 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 form a first recess 101, and a pair of notches located at the bottom of the container 100 form a second recess 102. That is, the first recess 101 and the second recess 102 are formed in the first side surface portion 110 and the second side surface portion 120 of the container 100, respectively, 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 is disposed in the second recess 102. The gas release valve 800 is a safety valve that releases pressure inside the container 100 if the pressure inside the container 100 increases excessively.

[0044] 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 disposed 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.

[0045] 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.

[0046] 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 is provided with 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.

[0047] In other words, the first recess 101 of the first side surface portion 110 is a recess where 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-shape) shape when viewed from the Y-axis direction. The second recess 102 of the first side surface portion 110 is a recess where 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-shape) shape when viewed from the Y-axis direction.

[0048] 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.

[0049] 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 its end in the positive 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 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.

[0050] 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.

[0051] In other words, the first recess 101 of the second side surface portion 120 is a recess where 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 where 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.

[0052] 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.

[0053] 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.

[0054] Container 100 includes a container body 160 and a lid 170, and is formed into a substantially rectangular parallelepiped shape by assembling container body 160 and lid 170. Container body 160 has a pair of long sides 130 and a bottom surface 150. 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.

[0055] 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 forming a pair of long sides 130 at both ends in the Y-axis direction, and a flat rectangular bottom wall portion forming the bottom surface 150 at the end in the negative Z-axis direction.

[0056] Lid 170 is a metal plate that is open downward when viewed from the Y-axis direction. 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 top surface 140 at its end in the positive Z-axis direction. A gas exhaust valve 800 is provided in lid 170 at locations corresponding to first bottom side surface 115 and second bottom side surface 125.

[0057] 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, aluminum alloy, iron, or plated steel sheet.

[0058] Although not shown in the drawings, a liquid injection portion is formed in the lid 170. The liquid injection portion is a portion for injecting an electrolyte into the container 100 when the energy storage device 10 is manufactured.

[0059] 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 for conducting electricity stored in the electrode assembly 700 to the external space of the energy storage element 10 and for introducing electricity into the internal space of the energy storage element 10 in order 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 of a conductive material such as aluminum, an aluminum alloy, copper, or a copper alloy, for example. The terminals 300 are connected (joined) to the current collector 600 by crimping, welding, or the like, and are attached to the lid 170.

[0060] In this 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.

[0061] 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. The material of the current collectors 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 a 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 a negative electrode current collector foil 751 of the electrode body 700 described later. Details of the current collectors 600 will be described later.

[0062] 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 electrically insulating resins 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 composite materials made by adding fillers to these resins.

[0063] The heat transfer insulating member 900 is a plate- or tape-shaped member interposed between the current collector 600 and the container 100, substantially insulating them electrically and transferring heat therebetween. Two heat transfer insulating members 900 are provided, one for each of the positive electrode current collector 610 and the negative electrode current collector 620. The heat transfer insulating member 900 is a member having electrical insulation and thermal conductivity. Specifically, the thermal conductivity of the heat transfer insulating member 900 is preferably 1.0 W / mK or more, and more preferably 3.0 W / mK or more, according to ASTM D5470. Furthermore, its electrical resistance is 1.0×10 when a DC voltage of 1500 V is applied, in terms of volume resistivity. 12 Ω·m or more is preferable, and 1.0×10 14 A resistance of Ω·m or more is more preferable. The thermal insulation member 900 may contain a thermally conductive material and an insulating material. Examples of thermally conductive materials include thermally conductive fillers and graphite. Examples of insulating materials include resin materials with high insulating properties. From the viewpoint of insulation, it is preferable that the thermally conductive material is not exposed from the surface of the insulating material.

[0064] More specifically, the thermal insulation member 900 may be an insulating resin material containing 30 wt% or more of flaky graphite, or an insulating resin material containing 22 wt% or more of a ceramic filler mainly composed of boron nitride.The thermal insulation member 900 may also be an adhesive tape having an adhesive layer on one or both sides, and a tape having an adhesive layer has excellent processability and workability.

[0065] [Electrode body] 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.

[0066] The positive electrode plate 740 is an electrode plate in which positive electrode active material layers 742 are 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 negative electrode active material layers 752 are 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 a material that can absorb and release ions through an electrochemical reaction.

[0067] Positive electrode active materials include polyanion compounds such as LiMPO4, LiMSiO4, and LiMBO3 (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), lithium titanate, LiMn2O4, and LiMn 1.5 Ni 0.5Examples of the negative electrode active material that can be used include spinel-type lithium manganese oxides such as LiMO2 (where M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.) and lithium transition metal oxides such as LiMO2 having an α-NaFeO2 crystal structure. Examples of the negative electrode active material include lithium metal, alloys capable of absorbing and desorbing lithium, carbon materials (graphite, non-graphitizable carbon, graphitizable carbon, low-temperature fired carbon, amorphous carbon, etc.), and silicon oxides.

[0068] 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.

[0069] 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 the negative electrode plate 750, the separator 761, the positive electrode plate 740, and the separator 762 in this order and winding them. 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 L is a straight line that passes through the center of the electrode assembly 700 and is parallel to the X-axis direction.

[0070] 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 arranged 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 arranged and the negative electrode current collector foil 751 is exposed (a portion where no negative electrode active material layer is formed). In FIG. 3, the portions where no active material layer is formed (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.

[0071] 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 portion 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) of the multiple electrode plates (positive electrode plate 740 and negative electrode plate 750) are stacked.

[0072] 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 plates of the same polarity (negative electrode plate 750) among the multiple electrode plates (positive electrode plate 740 and negative electrode plate 750) are stacked.

[0073] As described above, the electrode assembly 700 includes a main body portion 710 that constitutes the main body of the electrode assembly 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 assembly 700 includes a pair of tab portions that are composed of the positive electrode tab portion 721 and the negative electrode tab portion 722.

[0074] 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 arranged (formed, coated), a portion of the negative electrode plate 750 where the negative electrode active material layer 752 is arranged (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 an 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.

[0075] 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 from 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, a plurality of wound electrode plates and separators (positive electrode plate 740, negative electrode plate 750, separators 761, 762) are stacked in the Y-axis direction.

[0076] 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.).

[0077] [First heat transfer path] Next, a description will be given of the first heat transfer path 960 provided in the energy storage element 10. The first heat transfer path 960 is a portion that thermally connects the positive electrode current collector 610 and the inner wall of the container 100. In the present embodiment, the first heat transfer path 960 includes a heat transfer insulating member 900 connected to the current collector 600.

[0078] First, a detailed description will be given of the current collector 600 and the thermal insulating member 900. Here, the positive electrode current collector 610 will be taken as an example for description, but the same applies to the negative electrode current collector 620.

[0079] 6 and 7 are explanatory diagrams showing a positive electrode current collector 610 and a heat transfer insulator 900 according to the embodiment. Fig. 6 shows a cross-sectional view of the container 100 and the heat transfer insulator 900 as viewed from the negative Y-axis direction. Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 6 as viewed from the positive Z-axis direction.

[0080] Positive electrode current collector 610 integrally includes a terminal connection portion 630, a tab connection portion 640, and a linking portion 650. Terminal connection portion 630, tab connection portion 640, and linking portion 650 are each a flat plate-like portion, and are formed by bending a single piece of sheet metal.

[0081] Terminal connection portion 630 is a portion that is connected (joined) to positive electrode terminal 310 by crimping, welding, etc. Terminal connection portion 630 is a flat plate portion parallel to the XY plane, and coupling portion 650 is continuously connected to the end portion of terminal connection portion 630 in the positive X-axis direction.

[0082] The tab connection portion 640 is a portion that is connected (joined) to the positive electrode tab portion 721 by welding or the like. The tab connection portion 640 is a flat plate portion parallel to the XZ plane, and the connecting portion 650 is continuously connected to the end portion of the tab connection portion 640 in the positive X-axis direction. The surface of the tab connection portion 640 in the negative Y-axis direction is connected to the positive electrode tab portion 721. The tab connection portion 640 is an example of a connection portion that connects the current collector 600 and the electrode assembly 700.

[0083] The connecting portion 650 is a portion that connects the terminal connecting portion 630 and the tab connecting portion 640. The connecting portion 650 is a flat plate portion parallel to the YZ plane, and its end portion in the positive Z-axis direction is continuously connected to the terminal connecting portion 630, and its end portion in the positive Y-axis direction is continuously connected to the tab connecting portion 640.

[0084] The heat transfer insulator 900 is disposed between the connecting portion 650 of the positive electrode current collector 610 and the wall portion 119 of the container 100, including the first inner side surface 113. In this state, the heat transfer insulator 900 is parallel to the YZ plane. The heat transfer insulator 900 may be in direct contact with the connecting portion 650 and the wall portion 119, or may be in indirect contact with the connecting portion 650 and the wall portion 119 via a heat-conductive adhesive. As a result, heat generated at the tab connection portion 640 is transferred from the connecting portion 650 to the container 100 via the heat transfer insulator 900 and is released to the outside of the container 100. In other words, the heat transfer insulator 900 forms at least a part of a first heat transfer path 960 connecting the positive electrode current collector 610 and the container 100. The first heat transfer path 960 may be formed only by the heat transfer insulating member 900, or may be formed including other heat transfer members (such as the above-mentioned adhesive having heat conductivity).

[0085] Here, the heat transfer insulator 900 is preferably disposed at a position corresponding to the tab connection portion 640. Specifically, the heat transfer insulator 900 is disposed next to the tab connection portion 640 in the positive direction of the X axis. As shown in Fig. 6, the end of the heat transfer insulator 900 in the positive direction of the Z axis is disposed near the end of the tab connection portion 640 in the positive direction of the Z axis. The end of the heat transfer insulator 900 in the negative direction of the Z axis is disposed near the end of the tab connection portion 640 in the negative direction of the Z axis.

[0086] 7, the end of the heat transfer insulator 900 in the positive Y-axis direction is located near the end of the connecting part 650 in the positive Y-axis direction. The end of the heat transfer insulator 900 in the negative Y-axis direction is located near the end of the connecting part 650 in the negative Y-axis direction.

[0087] As a result, the length of the heat transfer insulator 900 in the Z-axis direction is at least half the length of the tab connection portion 640 in the Z-axis direction, and the length of the heat transfer insulator 900 in the Y-axis direction is at least half the length of the connecting portion 650 in the Y-axis direction. In this way, the heat transfer insulator 900 covers at least half of the connecting portion 650. Therefore, heat generated at the tab connection portion 640 can be smoothly transferred from the connecting portion 650 to the container 100 via the heat transfer insulator 900, thereby improving heat transfer.

[0088] [Second heat transfer path] Next, a second heat transfer path 970 provided in the energy storage device 1 will be described. The second heat transfer path 970 is a portion that thermally connects the terminal 300 and the exterior body 2. FIG. 8 is a partial cross-sectional view of the energy storage device 1 showing the second heat transfer path 970 according to the embodiment. As shown in FIG. 8, the second heat transfer path 970 includes a bus bar 50 and a heat transfer insulating member 950.

[0089] The bus bar 50 is a conductive member that extends uniformly in the Y-axis direction and is arranged to electrically connect the terminals 300 of two adjacent energy storage elements 10. When viewed from the Y-axis direction, the bus bar 50 is formed in a U-shape with its base pointing in the positive direction of the X-axis. The bus bar 50 integrally includes a first flat plate portion 51 that is connected to the terminal 300, a second flat plate portion 52 that faces the first flat plate portion 51 in the Z-axis direction, and a third flat plate portion 53 that connects the first flat plate portion 51 and the second flat plate portion 52. The bus bar 50 is formed by bending a single piece of sheet metal.

[0090] The heat transfer insulator 950 is disposed between the bus bar 50 and the exterior housing 2. The heat transfer insulator 950 is a member having electrical insulation and thermal conductivity, and is made of a material capable of forming the heat transfer insulator 900 described above. The heat transfer insulator 950 may be in direct contact with the pair of objects to be connected (the bus bar 50 and the exterior housing 2), or may be indirectly in contact with the pair of objects to be connected via a heat-conductive adhesive. As a result, heat generated in the terminal 300 is transferred from the bus bar 50 to the exterior housing 2 via the heat transfer insulator 950 and is released to the outside of the exterior housing 2.

[0091] Specifically, the heat transfer insulating member 950 integrally includes a flat plate-shaped first portion 951 and a second portion 952. The first portion 951 is disposed between the second flat plate portion 52 of the bus bar 50 and the exterior body cover 40 of the exterior body 2, and is in contact with a surface of the second flat plate portion 52 facing in the positive direction of the Z axis and a surface of the exterior body cover 40 facing in the negative direction of the Z axis.

[0092] The second portion 952 is disposed between the third flat plate portion 53 of the bus bar 50 and the side wall 33 of the exterior housing 2, and is in contact with a surface of the third flat plate portion 53 facing in the positive direction of the X axis and a surface of the side wall 33 facing in the negative direction of the X axis. In this manner, the heat transfer insulator 950 is in contact with each of a pair of connection objects (the bus bar 50 and the exterior housing 2) of the heat transfer insulator 950 on multiple surfaces facing different directions. Because the heat transfer insulator 950 is in contact with each of the pair of connection objects on multiple surfaces, the contact area can be increased, and the heat transfer performance through the second heat transfer path 970 can be improved.

[0093] Here, the bus bar 50 may have a structure in which it is pressed by the exterior body lid 40 when the exterior body lid 40 is attached to the exterior body main body 30 and is elastically deformed. Before being pressed by the exterior body lid 40, the bus bar 50 has a larger shape in the Z-axis direction than after being pressed, and is compressed and elastically deformed when pressed. In this case, the bus bar 50 attempts to elastically return to its original shape, thereby urging the energy storage device 10 toward the bottom wall 32 of the exterior body main body 30. In other words, the bus bar 50 is an example of a urging portion that urges the container 100 of the energy storage device 10 toward the exterior body 2.

[0094] [Third heat transfer path] Next, third heat transfer paths 981 and 982 provided in the energy storage device 1 will be described. The third heat transfer paths 981 and 982 are portions that thermally connect the container 100 of the energy storage element 10 and the exterior body 2. As shown in FIG. 8 , an example of the third heat transfer path 981 is formed by contact between the wall portion 119 of the container 100 and the side wall 33 of the exterior body 2. As a result, heat from the first heat transfer path 960 is transferred by the third heat transfer path 981 to the side wall 33 via the wall portion 119 and then released to the outside of the exterior body 2. Another example of the third heat transfer path 982 is formed by contact between the wall portion 118, which has a bottom surface 150 of the container 100, and the bottom wall 32 of the exterior body 2. Heat inside the container 100 is transferred by the third heat transfer path 982 to the bottom wall 32 via the wall portion 118 and then released to the outside of the exterior body 2. Here, the container 100 and the exterior body 2 may be in direct contact with each other, or may be in indirect contact with each other via a heat-conductive adhesive, a heat-conductive insulating member, or the like.

[0095] [Effect description] As described above, according to the embodiment, the heat transfer insulators 900, 950 are provided in the first heat transfer path 960 and the second heat transfer path 970, so that it is possible to improve heat transfer while ensuring insulation.

[0096] Specifically, the first heat transfer path 960 inside the energy storage element 10 includes the heat transfer insulating member 900, and therefore, while ensuring insulation even within the energy storage element 10, heat inside the energy storage element 10 can be transferred to the outside of the energy storage element 10 via the first heat transfer path 960. On the other hand, the second heat transfer path 970 outside the energy storage element 10 and inside the exterior housing 2 includes the heat transfer insulating member 950, and therefore, while ensuring insulation even within the exterior housing 2, heat from the energy storage element 10 can be transferred to the exterior housing 2 via the second heat transfer path 970.

[0097] Since the energy storage device 1 is provided with both the first heat transfer path 960 and the second heat transfer path 970, the heat generated within the energy storage element 10 can be efficiently transferred to the outer casing 2 and transferred from the outer casing 2, thereby further improving heat transfer.

[0098] By using adhesive tape as the heat transfer insulating member 900, which has excellent thermal conductivity, electrical insulation, and ease of work, it is possible to suppress an increase in thermal resistance due to electrical insulation.

[0099] The heat transfer insulator 900 is disposed in a position facing the connection (tab connection 640) where the current collector 600 and the electrode assembly 700 are connected, so that heat from the electrode assembly 700 can be smoothly transferred from the connection to the heat transfer insulator 900. This further improves heat transfer.

[0100] Since the second heat transfer path 970 includes the bus bar 50, the heat of the bus bar 50, which tends to become hot, can also be efficiently transferred by the heat transfer insulating member 950.

[0101] Since the bus bar 50 (biasing portion) biases the container 100 toward the outer casing 2, the contact between the container 100 and the outer casing 2 can be improved, and heat can be stably transferred to the outer casing 2 via the third heat transfer path 982.

[0102] Since the heat transfer insulating member 950 is in contact with each of the pair of connection objects (the bus bar 50 and the exterior body 2) on multiple surfaces, the contact area can be increased, and the heat transfer performance through the second heat transfer path 970 can be improved.

[0103] The electrical resistance of the heat transfer insulating material 950 is 1.0 x 10 when DC 1500V is applied in volume resistivity. 12 By ensuring a resistance of Ω·m or more and a thermal conductivity of 1.0 W / m·K or more according to the ASTM D5470 method, it is possible to ensure good thermal conductivity while maintaining electrical insulation.

[0104] (Description of Modifications) The following describes various modifications of the above embodiment. In the following description, the same parts as those in the above embodiment or other modifications are designated by the same reference numerals, and the description thereof may be omitted.

[0105] [Variation 1] In Modification 1, another connection configuration between the bus bar and the thermal insulating member will be described. Figures 9A to 9C are explanatory diagrams showing another connection configuration between the bus bar and the thermal insulating member according to Modification 1.

[0106] 9A, when viewed from the Y-axis direction, bus bar 50a is formed in a U-shape with its base pointing in the negative X-axis direction. Bus bar 50a integrally includes a first flat plate portion 51a connected to terminal 300, a second flat plate portion 52a facing first flat plate portion 51a in the Z-axis direction, and a third flat plate portion 53a connecting first flat plate portion 51a and second flat plate portion 52a.

[0107] The first portion 951 of the heat transfer insulating member 950 is arranged between the second flat plate portion 52a of the bus bar 50 and the exterior body cover 40 of the exterior body 2, and is in contact with the surface of the second flat plate portion 52 facing in the positive direction of the Z axis and the surface of the exterior body cover 40 facing in the negative direction of the Z axis.

[0108] The second portion 952 of the heat transfer insulator 950 is disposed between the first and second flat plate portions 51a and 52a of the bus bar 50 and the side wall 33 of the exterior body 2, and is in contact with the tip surfaces of the first and second flat plate portions 51a and 52a and the surface of the side wall 33 facing in the negative direction of the X axis. Even in this case, the heat transfer insulator 950 is in contact with each of the pair of objects to which the heat transfer insulator 950 is connected (the bus bar 50a and the exterior body 2) at multiple surfaces facing different directions.

[0109] 9B, bus bar 50b integrally includes a first flat plate portion 51b connected to terminal 300 and a second flat plate portion 52b extending in the positive Z-axis direction from the end of first flat plate portion 51b facing the negative X-axis direction. A first protrusion 54b protruding in the positive Z-axis direction is formed at the end of first flat plate portion 51b facing the positive X-axis direction. A second protrusion 55b protruding in the positive X-axis direction is formed at the end of second flat plate portion 52b facing the positive Z-axis direction.

[0110] The heat-transfer insulating member 950b is divided into two pieces, and one of the heat-transfer insulating members 950b is arranged between the first protrusion portion 54b and the side wall 33 of the exterior body 2, and is in contact with the surface of the first protrusion portion 54b facing in the positive direction of the X-axis and the surface of the side wall 33 facing in the negative direction of the X-axis.

[0111] The other heat transfer insulator 950b is disposed between the second protrusion 55b and the exterior body lid 40 of the exterior body 2, and is in contact with the surface of the second protrusion 55b facing in the positive direction along the Z axis and the surface of the exterior body lid 40 facing in the negative direction along the Z axis. In this case as well, the heat transfer insulator 950b is in contact with each of the pair of connection targets (the bus bar 50b and the exterior body 2) of the heat transfer insulator 950b at multiple surfaces facing in different directions.

[0112] In the connection form shown in FIG. 9C, the bus bar 50c integrally includes a first flat plate portion 51c connected to the terminal 300 and a second flat plate portion 52c extending in the positive direction of the Z axis from the end of the first flat plate portion 51c in the positive direction of the X axis.

[0113] The heat transfer insulator 950c is disposed between the second flat plate portion 52c and the side wall 33 of the exterior body 2, and is in contact with a surface of the second flat plate portion 52c facing in the positive direction along the X axis and a surface of the side wall 33 facing in the negative direction along the X axis. As in this case, the heat transfer insulator 950c may be in contact with each of a pair of connection targets (the bus bar 50c and the exterior body 2) of the heat transfer insulator 950c on one surface.

[0114] [Variation 2] A modification of the urging portion will be described in Modification 2. Fig. 10 is a partial cross-sectional view of the power storage device 1D showing a urging portion 850d according to Modification 2. Fig. 10 is a view corresponding to Fig. 8.

[0115] As shown in FIG. 10 , the biasing member 850d is disposed between the bottom surface 150 of the energy storage element 10 and the bottom wall 32 of the exterior body 2. The biasing member 850d is a sheet-like elastic body made of rubber, sponge, urethane, or the like. The biasing member 850d is disposed between the bottom surface 150 and the bottom wall 32 in a compressed state. Therefore, the biasing member 850d attempts to elastically return to its original position, pressing the energy storage element 10 in the positive direction of the Z axis. That is, the bus bar 50 and the heat transfer insulator 950, which are part of the second heat transfer path 970, are also pressed toward the exterior body cover 40. This improves contact between the second heat transfer path 970 and the exterior body 2, enabling stable heat transfer to the exterior body 2.

[0116] [Variation 3] In Modification 3, a modification of the heat transfer insulator in the energy storage device will be described. Fig. 11 is a partial cross-sectional view of an energy storage device 10e showing a heat transfer insulator 900e according to Modification 3. Fig. 11 is a view corresponding to Fig. 7.

[0117] 11, the heat transfer insulator 900e integrally includes a first flat portion 901e and a second flat portion 902e. The first flat portion 901e is disposed between the connecting portion 650 of the positive electrode current collector 610 and the wall portion 119 of the container 100, and is in contact with the surface of the connecting portion 650 facing in the positive direction of the X-axis and the surface of the wall portion 119 facing in the negative direction of the X-axis.

[0118] The second flat portion 902e is arranged between the tab connection portion 640 of the positive electrode current collector 610 and the wall portion 117 of the container 100, which has a long side surface 130 in the positive direction of the Y axis, and is in contact with the surface of the tab connection portion 640 facing the positive direction of the Y axis and the surface of the wall portion 117 facing the negative direction of the Y axis.

[0119] In this way, the heat transfer insulator 900e is in contact with each of the pair of connection targets (the current collector 600 and the container 100) on multiple surfaces facing different directions. Because the heat transfer insulator 900e is in contact with each of the pair of connection targets on multiple surfaces, the contact area can be increased, and the heat transfer through the first heat transfer path 960a can be improved.

[0120] [Variation 4] In Modification 4, a modification of the heat transfer insulator in the energy storage device will be described. Fig. 12 is a partial cross-sectional view of an energy storage device 10f showing a heat transfer insulator 900f according to Modification 4. Fig. 12 is a view corresponding to Fig. 7.

[0121] As shown in FIG. 12 , the heat transfer insulator 900f is interposed between the electrode assembly 700 and the container 100 to thermally connect them. Specifically, the heat transfer insulator 900f contacts both the positive electrode tab portion 721 of the electrode assembly 700 and the wall portion 116 of the container 100, including the long side surface 130 facing the negative Y-axis direction. Heat generated in the positive electrode tab portion 721 is transferred to the wall portion 116 via the heat transfer insulator 900f and dissipated to the outside of the container 100. In this manner, the heat transfer insulator 900f forms a first heat transfer path 960f that thermally connects the electrode assembly 700 and the container 100. While this modification illustrates a case in which the heat transfer insulator 900f contacts the positive electrode tab portion 721, it may also contact the main body portion 710 of the electrode assembly 700.

[0122] [Variation 5] In Modification 5, a modification of the heat transfer insulating member outside the energy storage elements will be described. Fig. 13 is a partial cross-sectional view of an energy storage device 1G showing a heat transfer insulating member 950g according to Modification 5. Fig. 13 is a view corresponding to Fig. 8.

[0123] 13, bus bar 50g is formed in a flat plate shape and is separated from package 2 while being connected to terminal 300. In other words, bus bar 50g is not thermally connected to package 2.

[0124] The heat transfer insulator 950g is disposed between the container 100 of the energy storage element 10 and the exterior housing 2. Specifically, the heat transfer insulator 950g is disposed between the first inner side surface 113 of the container 100 and the side wall 33 of the exterior housing 2, and is in contact with these. Therefore, heat generated in the container 100 is transferred to the exterior housing 2 via the heat transfer insulator 950g and released to the outside of the exterior housing 2. In this way, the heat transfer insulator 950g forms a second heat transfer path 970g that thermally connects the container 100 of the energy storage element 10 and the exterior housing 2.

[0125] [Variation 6] In Modification 6, a modification of the container of the energy storage element will be described. Fig. 14 is a partial cross-sectional view showing a container 100h according to Modification 6. Fig. 14 is a view corresponding to Fig. 8.

[0126] As shown in FIG. 14 , unlike the container 100 of the above embodiment, the container 100h does not include a first recess 101 or a second recess 102. That is, the container 100h is formed in a rectangular parallelepiped shape. A terminal 300h is installed on a top surface 140h of the container 100h via an external gasket 400h. A thermal insulating member 950h is connected to the terminal 300h via a flat bus bar 50h. As a result, heat generated in the terminal 300h is transferred from the bus bar 50h through the thermal insulating member 950h to the exterior body 2 and is released to the outside of the exterior body 2.

[0127] [Variation 7] In Modification 7, an energy storage device 1J having a cooling function will be described. FIG. 15 is a perspective view showing the energy storage device 1J according to Modification 7. As shown in FIG. 15, a refrigerant pipe 990j is provided on the outer surface of an exterior body 2 included in the energy storage device 1J. Specifically, the refrigerant pipe 990j is 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 exterior body cover 40. A refrigerant such as a gas or liquid flows through the refrigerant pipe 990j. The refrigerant pipe 990j and the exterior body 2 are thermally connected by being joined by welding. By flowing a refrigerant through the refrigerant pipe 990j, the exterior body 2 is cooled. In other words, exhaust heat from the energy storage elements 10 can be removed.

[0128] Here, the case where the exterior body 2 is cooled from the outside of the exterior body 2 by the refrigerant pipe 990j has been exemplified. However, the refrigerant pipe may be embedded in at least one of the bottom wall 32, the side wall 33, and the exterior body lid 40, or may be disposed in the internal space of the exterior body 2.

[0129] (others) Although the power storage device and the like according to the embodiment of the present invention (including its modified examples, the same applies hereinafter) have been described above, the present invention is not limited to the above-described embodiment. The embodiment disclosed here is an example in all respects, and the scope of the present invention includes all modifications within the meaning and scope of the claims.

[0130] For example, in the above embodiment, the first heat transfer path 960 and the second heat transfer path 970 are respectively provided with the heat transfer insulators 900, 950. However, only one of the first heat transfer path and the second heat transfer path may be provided with a heat transfer insulator. Furthermore, the power storage device may be provided with only one of the first heat transfer path and the second heat transfer path.

[0131] In the above embodiment, the case where the container 100 is in contact with the exterior body 2 is illustrated, but the container may be separated from the exterior body.

[0132] Any combination of the components included in the above-described embodiments and their modifications is also included within the scope of the present invention. [Industrial Applicability]

[0133] The present invention can be applied to an energy storage element such as a lithium ion secondary battery and an energy storage device including the same. [Explanation of symbols]

[0134] 1, 1D, 1G, 1J power storage device 2. Exterior body 10, 10e, 10f storage element 30 Exterior body 40 Exterior body lid 50, 50a, 50b, 50c, 50g, 50h busbars 100, 100h container 160 Container body 170 Lid 300, 300h terminals 600 current collector 700 Electrode body 720 Tab section 800 Gas Exhaust Valve 850d Force part 900, 900e, 900f, 950, 950b, 950c, 950g, 950h Heat transfer insulation material 960, 960a, 960f First heat transfer path 970, 970g Second heat transfer path 981, 982 Third heat transfer path

Claims

1. An electricity storage device including an electricity storage element and an exterior body that houses the electricity storage element, The storage element is An electrode body; a current collector electrically connected to the electrode body; a container that accommodates the electrode assembly and the current collector; a terminal disposed on the outer surface of the container and electrically connected to the current collector; The heat transfer device includes at least one of a first heat transfer path that thermally connects the electrode body or the current collector to the container and is substantially electrically insulated by providing a heat transfer insulating member in the path, and a second heat transfer path that thermally connects the container or the terminal to the exterior body and is substantially electrically insulated by providing a heat transfer insulating member in the path. Energy storage device.

2. The first heat transfer path and the second heat transfer path are both provided. The power storage device according to claim 1 .

3. The thermal insulating member is an adhesive tape. The electricity storage device according to claim 1 or 2.

4. the heat transfer insulating member is disposed at a position facing a connection portion where the current collector and the electrode body are connected. The power storage device according to claim 3 .

5. a bus bar that electrically connects between the terminals of the energy storage elements and at least one of between the external terminals provided on the exterior body and the terminals; The second heat transfer path includes the bus bar. The electricity storage device according to claim 1 or 2.

6. a biasing portion that biases at least one of the second heat transfer path and the container toward the exterior body; The electricity storage device according to claim 1 or 2.

7. the heat transfer insulator is in contact with at least one of a pair of connection objects connected to the heat transfer insulator on multiple surfaces; The electricity storage device according to claim 1 or 2.

8. The electrical resistance of the heat transfer insulating member is 1.0×10 when a direct current of 1500 V is applied in terms of volume resistivity. １２ Ω・m or more, and thermal conductivity is 1.0 W / m・K or more according to ASTM D5470 method The electricity storage device according to claim 1 or 2.

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