Energy storage device

Abstract

To provide a power storage device that can improve reliability.SOLUTION: A power storage device 1 includes a plurality of power storage elements 100 arranged along a first direction (Y-axis direction), and a resin exterior body 300 that collectively holds the plurality of power storage elements 100. The resin exterior body 300 has that exposes at least a portion of the side surfaces (short side surfaces 112) of at least two adjacent power storage elements 100 in a second direction (Z-axis direction) perpendicular to the first direction, which is the whole portion in the first direction from among the power storage elements 100.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a power storage device including a power storage element.

Background Art

[0002] For example, Patent Document 1 discloses a battery unit (power storage device) in which a plurality of rectangular parallelepiped secondary batteries (power storage elements) are held by a resin cell holder (resin exterior). The resin exterior covers the entire short side surface of each power storage element.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above conventional power storage device, since the entire short side surface of each power storage element is covered with the resin exterior, the heat of the power storage element during charge and discharge is difficult to be released to the outside, and there is a risk that the power storage element is likely to deteriorate.

[0005] Therefore, an object of the present invention is to provide a power storage device capable of enhancing reliability.

Means for Solving the Problems

[0006] A power storage device according to an aspect of the present invention includes a plurality of power storage elements arranged along a first direction, and a resin exterior that holds the plurality of power storage elements together. The resin exterior has a shape that exposes at least a part of a side surface of at least two adjacent power storage elements among the plurality of power storage elements in a second direction orthogonal to the first direction and exposes the entire first direction.

Effects of the Invention

[0007] The energy storage device according to the present invention can improve reliability. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view showing the external appearance of the energy storage device according to the embodiment. [Figure 2] This is an exploded perspective view showing the components of the energy storage device according to the embodiment when it is disassembled. [Figure 3] This is a perspective view showing the configuration of the energy storage element according to the embodiment. [Figure 4] This is a perspective view showing the configuration of a resin tray according to an embodiment. [Figure 5] This is a perspective view showing the configuration of the retaining member according to the embodiment. [Figure 6] This is a perspective view showing the locked state between the locking piece and the claw portion according to the embodiment. [Figure 7] This is a perspective view showing the resin casing according to the embodiment assembled to multiple energy storage elements. [Figure 8A] This is a schematic plan view showing the resin exterior body according to Modification Example 1. [Figure 8B] This is a schematic plan view showing the resin exterior body according to Modification Example 2. [Modes for carrying out the invention]

[0009] An energy storage device according to one aspect of the present invention comprises a plurality of energy storage elements arranged along a first direction and a resin casing that holds the plurality of energy storage elements together, wherein the resin casing has a shape that exposes at least a portion of the sides of at least two adjacent energy storage elements in a second direction perpendicular to the first direction, and the entire side in the first direction.

[0010] According to this, the resin casing exposes at least a portion of the sides of at least two adjacent energy storage elements in the second direction, while exposing the entire side in the first direction. This increases the exposed area of ​​the energy storage elements. As a result, heat generated during charging and discharging can be easily dissipated, and degradation of the energy storage elements can be suppressed. Therefore, the reliability of the energy storage device can be improved.

[0011] The resin casing may have a shape that exposes at least a portion of the sides of the plurality of energy storage elements in the second direction, and the entirety of the sides in the first direction.

[0012] According to this, the resin casing exposes at least a portion of the sides of the multiple energy storage elements in the second direction, and the entirety in the first direction, thus increasing the exposed area of ​​the energy storage elements as a whole. This enhances the effect of suppressing the degradation of the energy storage elements. Therefore, it is possible to further improve the reliability of the energy storage device.

[0013] The resin casing may include a resin tray on which the plurality of energy storage elements are placed, and a resin pressing member that sandwiches the plurality of energy storage elements between the resin tray.

[0014] According to this, even in an energy storage device in which multiple energy storage elements are sandwiched between a resin tray and a retaining member, at least a portion of the side surfaces of at least two energy storage elements in the second direction, and the entire surface in the first direction, can be continuously exposed. In other words, even in such an energy storage device, the degradation suppression effect can be achieved, and reliability can be improved.

[0015] At least one of the resin tray and the retaining member may have a partition that separates the two energy storage elements.

[0016] According to this, since the partition portion partitions two adjacent power storage elements, the positions of these power storage elements can be regulated. For example, in the case of two power storage elements whose sides are continuously exposed, it is difficult to regulate the position on the side surface side. However, if a partition portion is provided on at least one of the resin tray and the pressing member, the positions of these two power storage elements can be reliably regulated.

[0017] The power storage device has a pair of metal plates that sandwich the resin tray and the pressing member in the arrangement direction of the resin tray and the pressing member. The pair of metal plates may be joined in a state where at least a part of the sides of at least two adjacent power storage elements in the second direction and the entire first direction are exposed.

[0018] According to this, since the pair of metal plates sandwich the resin tray and the pressing member in the arrangement direction and are joined to each other, the shape of the entire power storage device can be stabilized. As a result, the reliability of the power storage device can be further enhanced.

[0019] An exhaust member that serves as an exhaust path for the gas discharged from the plurality of power storage elements may be arranged on the pressing member.

[0020] According to this, since the gas discharged from the plurality of power storage elements can be collected and discharged by the exhaust member, the spread of fire in the resin exterior can be suppressed.

[0021] The pressing member may form a part of the exhaust path of the gas.

[0022] According to this, since the pressing member can be used as a part of the exhaust path of the gas, there is no need to prepare a dedicated member, and the cost can be suppressed.

[0023] The power storage device may include a bracket that presses the exhaust member.

[0024] According to this, since the bracket holds down the exhaust member, the outflow of gas from the exhaust member can be suppressed, and the spread of fire of the resin exterior can be further suppressed.

[0025] The following description of an energy storage device according to an embodiment (including its modifications) of the present invention will be given with reference to the drawings. The embodiments described below are all general or specific examples. The numerical values, shapes, materials, components, arrangement and connection configurations of components, manufacturing processes, and the order of manufacturing processes shown in the following embodiments are examples only and are not intended to limit the present invention. Dimensions in each figure are not precisely illustrated. In each figure, the same or similar components are denoted by the same reference numerals.

[0026] In the following description and drawings, the direction in which a pair of electrode terminals (positive and negative) of a single energy storage element are aligned, the direction in which the short sides of the energy storage element's container face each other, or the direction of the short side of the outer casing is defined as the X-axis direction. The direction in which multiple energy storage elements are aligned, the direction in which the long sides of the energy storage element's container face each other, the direction in which the energy storage elements and spacers are aligned, or the direction of the long side of the outer casing is defined as the Y-axis direction. The direction in which energy storage elements and busbars are aligned, the direction in which the body and lid of the energy storage element's container are aligned, the direction in which the body and lid (resin tray and retaining member) of the outer casing are aligned, the direction in which the body and lid (first support and second support) of the outer casing support are aligned, or the vertical direction is defined as the Z-axis direction. These X-axis, Y-axis, and Z-axis directions intersect each other (orthogonal in this embodiment). Depending on the usage, the Z-axis direction may not be the vertical direction, but for the sake of explanation below, the Z-axis direction will be described as the vertical direction.

[0027] In the following explanation, the X-axis positive direction refers to the direction of the X-axis arrow, and the X-axis negative direction refers to the opposite direction. When simply referred to as the X-axis direction, it refers to either the X-axis positive direction or the X-axis negative direction, or either direction. The same applies to the Y-axis and Z-axis directions. In the following, the Y-axis direction may also be referred to as the first direction, the X-axis direction as the third direction, and the Z-axis direction as the second direction. Expressions indicating relative directions or orientations, such as parallel and orthogonal, may include cases where they are not strictly those directions or orientations. For example, two directions being parallel means not only that the two directions are perfectly parallel, but also that they are substantially parallel, i.e., they may have a difference of, for example, a few percent. Furthermore, in the following explanation, when the term "insulation" is used, it means "electrical insulation."

[0028] (Embodiment) [1. General description of energy storage device 1] First, a general description of the energy storage device 1 in this embodiment will be given. Figure 1 is a perspective view showing the external appearance of the energy storage device 1 according to this embodiment. Figure 2 is an exploded perspective view showing the individual components when the energy storage device 1 according to this embodiment is disassembled.

[0029] The energy storage device 1 is a device that can charge electricity from an external source and discharge electricity to the outside, and in this embodiment, it has a substantially rectangular parallelepiped shape. For example, the energy storage device 1 is a battery module (battery pack) used for power storage or power supply purposes. Specifically, the energy storage device 1 is used as a battery for driving or starting the engine of mobile vehicles such as automobiles, motorcycles, watercraft, ships, snowmobiles, agricultural machinery, construction machinery, or railway vehicles for electric railways. Examples of automobiles include electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and fossil fuel (gasoline, diesel, liquefied natural gas, etc.) vehicles. Examples of railway vehicles for electric railways include electric trains, monorails, linear motor cars, and hybrid trains equipped with both diesel engines and electric motors. The energy storage device 1 can also be used as a stationary battery for household or commercial use.

[0030] As shown in Figure 1, the energy storage device 1 comprises an energy storage unit 10 and a circuit board unit 20 attached to the energy storage unit 10. The energy storage unit 10 has a roughly rectangular parallelepiped shape that is elongated in the Y-axis direction. The circuit board unit 20 is a device that can monitor the state of the energy storage elements 100 in the energy storage unit 10 and control the energy storage elements 100, and has a circuit board etc. inside. In this embodiment, the circuit board unit 20 is a flat rectangular member attached to the longitudinal end of the energy storage unit 10, that is, the side of the energy storage unit 10 on the negative Y-axis side.

[0031] Furthermore, as shown in Figure 2, the energy storage unit 10 includes a plurality of energy storage elements 100, a plurality of spacers 200, a resin casing 300, a plurality of busbars 400, a casing support 500, and cables 410 and 420.

[0032] The energy storage element 100 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 100 has a flattened rectangular parallelepiped shape (square), and in this embodiment, 14 energy storage elements 100 are arranged in the Y-axis direction. The size, shape, and number of energy storage elements 100 arranged are not limited, and for example, only one energy storage element 100 may be arranged. The energy storage element 100 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 it may be a capacitor. The energy storage element 100 may not be a secondary battery, but a primary battery that allows the user to use the stored electricity without charging. The energy storage element 100 may be a battery using a solid electrolyte. The energy storage element 100 may be a pouch-type energy storage element. A detailed explanation of the configuration of the energy storage element 100 will be given later.

[0033] Spacers 200 (210, 220) are flat, rectangular members arranged alongside the energy storage element 100 in the Y-axis direction (first direction) to provide thermal insulation and / or isolation between the energy storage element 100 and other members. Spacers 200 are thermal insulation plates or insulating plates arranged in the Y-axis positive or Y-axis negative direction of the energy storage element 100 to provide thermal insulation and / or isolation between the energy storage elements 100 themselves or between the energy storage elements 100 and the outer casing support 500. Spacers 200 are made of a thermal insulation material such as mica, or an insulating material such as any resin material that can be used for the resin outer casing 300 described later. Spacers 210 and 220 of spacers 200 may be made of the same material or of different materials.

[0034] Spacer 210, one of the spacers 200, is a flat, rectangular spacer (intermediate spacer) parallel to the XZ plane, positioned between two adjacent energy storage elements 100 to provide thermal insulation and / or isolation between the two energy storage elements 100. Specifically, the spacer 210 is positioned between the long sides 111 of the containers 110 (described later) of the two energy storage elements 100, facing the long sides 111. In this embodiment, 13 spacers 210 are arranged alternately with 14 energy storage elements 100 in the Y-axis direction, but if the number of energy storage elements 100 is other than 14, the number of spacers 210 is appropriately changed according to the number of energy storage elements 100. The spacers 210 are not limited to being positioned between all of the energy storage elements 100; a configuration in which no spacers 210 are positioned between any of the energy storage elements 100 is also possible. All spacers 210 may be made of the same material, or any of the spacers 210 may be made of a different material.

[0035] Spacer 220, one of the spacers 200, is a flat, rectangular spacer (end spacer) parallel to the XZ plane, positioned between the end energy storage element 100 and the side wall of the outer casing support 500, providing thermal insulation and / or isolation between the end energy storage element 100 and the side wall of the outer casing support 500. Two spacers 220 are positioned between the energy storage elements 100 located at both ends in the Y-axis direction and the side walls of the outer casing support 500 at both ends in the Y-axis direction. Specifically, the spacers 220 are positioned between the long side surface 111 of the container 110 of the energy storage element 100 at the Y-axis end and the side wall of the outer casing support 500 facing it in the Y-axis direction, facing the long side surface 111 and the side wall of the outer casing support 500. The two spacers 220 may be made of the same material or of different materials.

[0036] The resin casing 300 is positioned outside the multiple energy storage elements 100 and the multiple spacers 200, and is a component that constitutes a housing (outer shell of the energy storage unit 10) that covers the multiple energy storage elements 100, etc. Specifically, the resin casing 300 is positioned on both sides of the multiple energy storage elements 100 in the Z-axis direction, sandwiching the multiple energy storage elements 100 and the multiple spacers 200 in the Z-axis direction, and covers both ends of the multiple energy storage elements 100, etc. in the Z-axis direction. In this way, the resin casing 300 holds the multiple energy storage elements 100 and the multiple spacers 200 together and fixes them in a predetermined position.

[0037] The resin casing 300 is formed from insulating materials 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), polyetheretherketone (PEEK), tetrafluoroethylene perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyethersulfone (PES), polyamide (PA), ABS resin, or composite materials thereof, or from metal with an insulating coating. The resin casing 300 thereby prevents the energy storage element 100, etc. from coming into contact with external metal components, etc. The resin casing 300 may be formed from conductive materials such as metal, as long as the insulating properties of the energy storage element 100, etc. are maintained.

[0038] The resin casing 300 includes a resin tray 310 that constitutes the lower part of the resin casing 300 and a retaining member 320 that constitutes the upper part of the resin casing 300. The resin tray 310 and the retaining member 320 may be made of the same material or of different materials.

[0039] The resin tray 310 is a long tray in the Y-axis direction. Specifically, the resin tray 310 is a long, shallow box-shaped (flat, roughly rectangular) tray in the Y-axis direction, arranged in the negative Z-axis direction for multiple energy storage elements 100 and multiple spacers 200, on which the multiple energy storage elements 100 and the like are placed.

[0040] The retaining member 320 is a long, box-shaped (flat, roughly rectangular) member in the Y-axis direction, positioned in the Z-axis positive direction of the multiple energy storage elements 100 and the multiple spacers 200, and placed on the multiple energy storage elements 100. Since the retaining member 320 is positioned between the second support 520 of the outer casing support 500 (described later) and the energy storage elements 100, it can also be said to be the inner lid of the energy storage unit 10. In this embodiment, the retaining member 320 is a busbar frame (also called a busbar holder or busbar plate), and provides insulation between the busbars 400 and other members, and restricts the position of the busbars 400. Specifically, the retaining member 320 is placed on the multiple energy storage elements 100 and positioned relative to the multiple energy storage elements 100, and the multiple busbars 400 are positioned relative to the retaining member 320. As a result, each busbar 400 is positioned relative to the multiple energy storage elements 100 and joined to the electrode terminals 140 of the multiple energy storage elements 100. A detailed explanation of the configuration of the resin casing 300 (resin tray 310 and retaining member 320) will be given later.

[0041] The busbar 400 is a rectangular plate-shaped member that is placed on a plurality of energy storage elements 100 and electrically connects the electrode terminals 140 of the plurality of energy storage elements 100. In this embodiment, the busbar 400 and the electrode terminals 140 are connected (joined) by bolt fastening, but they may also be connected (joined) by welding or the like. The busbar 400 is made of a conductive material made of metal such as aluminum, aluminum alloy, copper, copper alloy, nickel, or a combination thereof, or a conductive material other than metal. In this embodiment, the busbar 400 connects 14 energy storage elements 100 in series by connecting the electrode terminals 140 of adjacent energy storage elements 100, but the connection configuration of the energy storage elements 100 is not limited to the above, and series and parallel connections may be combined in any way.

[0042] The electrode terminals 140 of the energy storage elements 100 located at both ends in the Y-axis direction among the multiple energy storage elements 100 are connected to cables 410 and 420, thereby enabling the energy storage device 1 to charge with electricity from an external source and discharge electricity to the outside. Cables 410 and 420 are the positive and negative electrode wires (power cables) through which current flows for charging and discharging the energy storage device 1 (energy storage elements 100).

[0043] The exterior support 500 is a component that supports and protects (reinforces) the resin exterior 300. The exterior support 500 is made of a metal component such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet. The exterior support 500 has a first support 510 that constitutes the main body of the exterior support 500 and a second support 520 that constitutes the lid of the exterior support 500. The first support 510 and the second support 520 may be made of the same material or of different materials.

[0044] The first support 510 is a metal plate on which the resin tray 310 is placed and which supports the resin tray 310 from below (in the negative Z-axis direction), and has a bottom portion 511 and connecting portions 512 and 513. The bottom portion 511 is a flat, rectangular portion that constitutes the bottom of the energy storage unit 10, is parallel to the XY plane and extends in the Y-axis direction, and is positioned in the negative Z-axis direction of the resin tray 310. Multiple locking pieces 511a are formed on each edge of the bottom portion 511 in the X-axis direction, which lock onto the resin tray 310. The multiple locking pieces 511a protrude in the positive Z-axis direction from the ends in the positive Y-axis direction, the central part in the Y-axis direction, and the ends in the negative Y-axis direction, respectively, at each of the opposing edges of the bottom portion 511 in the X-axis direction. Furthermore, at the bottom portion 511, flat, rectangular ribs 511b are formed on each edge between a plurality of locking pieces 511a, extending in the Y-axis direction and parallel to the YZ plane. Each rib 511b is formed lower than the height (length in the Z-axis direction) of the locking piece 511a.

[0045] The connecting portion 512 is a plate-shaped portion that is erected in the Z-axis positive direction from the Y-axis negative end of the bottom portion 511 and protrudes in the Y-axis negative direction, and is connected to the second support 520. The connecting portion 513 is a plate-shaped portion that is erected in the Z-axis positive direction from the Y-axis positive end of the bottom portion 511 and protrudes in the Y-axis positive direction, and is connected to the second support 520.

[0046] The second support 520 is a metal plate that presses against and supports the retaining member 320 from above (in the positive Z-axis direction), and has a top surface portion 521 and connecting portions 522 and 523. The top surface portion 521 is a flat, rectangular portion that constitutes the top surface portion (outer cover) of the energy storage unit 10, is parallel to the XY plane and extends in the Y-axis direction, and is positioned in the positive Z-axis direction of the retaining member 320. The connecting portion 522 is a portion that extends from the Y-axis negative end of the top surface portion 521 in the Z-axis negative direction and protrudes in the Y-axis negative direction, and is connected to the connecting portion 512 of the first support 510. The connecting portion 523 is a portion that extends from the Y-axis positive end of the top surface portion 521 in the Z-axis negative direction and protrudes in the Y-axis positive direction, and is connected to the connecting portion 513 of the first support 510.

[0047] In this configuration, the first support 510 and the second support 520 are fixed by connecting (joining) the connecting parts 512 and 513 and the connecting parts 522 and 523 with screws or the like, while sandwiching the resin tray 310 and the pressing member 320 from the Z-axis direction. As a result, the outer casing support 500 supports (holds) the resin outer casing 300.

[0048] [2. Description of the energy storage element 100] Next, the configuration of the energy storage element 100 will be described in detail. Figure 3 is a perspective view showing the configuration of the energy storage element 100 according to this embodiment. Figure 3 shows an enlarged view of the appearance of one of the multiple energy storage elements 100 shown in Figure 2. Since all of the multiple energy storage elements 100 have the same configuration, the configuration of one energy storage element 100 will be described in detail below.

[0049] As shown in Figure 3, the energy storage element 100 comprises a container 110 and a pair of electrode terminals 140 (positive and negative). Inside the container 110 are the electrode bodies, a pair of current collectors (positive and negative), and an electrolyte (non-aqueous electrolyte), but these are not shown in the illustration. There are no particular restrictions on the type of electrolyte as long as it does not impair the performance of the energy storage element 100, and various types can be selected. The energy storage element 100 is equipped with an insulating gasket that insulates and seals the container 110, the electrode terminals 140, and the current collectors, but this is also not shown in the illustration.

[0050] In addition to the above-mentioned components, the energy storage element 100 may also have spacers positioned to the side or below the electrode body, and an insulating film that encloses the electrode body, etc. An insulating film (such as a shrink tube) may be placed around the container 110 to cover the outer surface of the container 110. The material of the insulating film is not particularly limited as long as it can ensure the necessary insulation for the energy storage element 100, but examples include insulating resins such as PC, PP, PE, PPS, PET, PBT, or ABS resin, epoxy resin, Kapton®, Teflon®, silicon, polyisoprene, and polyvinyl chloride.

[0051] The container 110 is a rectangular parallelepiped (square or box-shaped) case having a container body 120 with an opening and a lid 130 that closes the opening of the container body 120. The container body 120 is a rectangular cylindrical member with a bottom that constitutes the main body of the container 110, and has an opening on the Z-axis positive side. The lid 130 is a rectangular plate-shaped member that constitutes the lid of the container 110, and is arranged extending in the X-axis direction in the Z-axis positive direction of the container body 120. The container 110 (lid 130) is provided with a gas discharge valve 131 that releases pressure when the pressure inside the container 110 rises excessively, and an injection part (not shown) for injecting electrolyte into the container 110. The material of the container 110 (container body 120 and lid 130) is not particularly limited and can be a weldable (joinable) metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet, but resin can also be used.

[0052] The container 110 has a structure in which the inside is sealed by welding or the like to the container body 120 after the electrode body and the lid 130 are placed inside the container body 120. The container 110 has a pair of long sides 111 on both sides in the Y-axis direction, a pair of short sides 112 on both sides in the X-axis direction, and a bottom surface 113 on the negative Z-axis side. The long sides 111 are rectangular planar portions parallel to the XZ plane that form the long sides of the container 110, and are positioned opposite adjacent spacers 200 in the Y-axis direction. The long sides 111 are adjacent to the short sides 112 and the bottom surface 113, and have a larger area than the short sides 112. The short sides 112 are rectangular planar portions parallel to the YZ plane that form the short sides of the container 110. The short sides 112 are adjacent to the long sides 111 and the bottom surface 113, and have a smaller area than the long sides 111. The bottom surface 113 is a rectangular planar portion parallel to the XY plane that forms the bottom surface of the container 110, and is positioned adjacent to the long side surface 111 and the short side surface 112.

[0053] The electrode terminals 140 are terminal members (positive and negative electrode terminals) of the energy storage element 100, which is positioned on the cover portion 130, and are electrically connected to the positive and negative electrode plates of the electrode body via a current collector. The electrode terminals 140 are metal members that lead the electricity stored in the electrode body to the external space of the energy storage element 100 and introduce electricity into the internal space of the energy storage element 100 to store electricity in the electrode body. The electrode terminals 140 are made of aluminum, aluminum alloy, copper, copper alloy, or the like.

[0054] The electrode body is an energy storage element (power generation element) formed by laminating a positive electrode plate, a negative electrode plate, and a separator. The positive electrode plate has a positive electrode active material layer formed on a positive electrode base layer, which is a current collector foil made of a metal such as aluminum or an aluminum alloy. The negative electrode plate has a negative electrode active material layer formed on a negative electrode base layer, which is a current collector foil made of a metal such as copper or a copper alloy. As for the active material used in the positive electrode active material layer and the negative electrode active material layer, any known material can be used as long as it is capable of intercalating and deintercalating lithium ions. For example, the positive electrode active material layer contains a ternary positive electrode active material mainly composed of Li, Ni, Co, and Mn, and the negative electrode active material layer contains graphite. The positive electrode active material layer may also be LiMn2O4, LiFePO4, LiCO2, LiNiO2, etc., and is not particularly limited. The negative electrode active material may also be carbon-based materials (soft carbon, hard carbon, etc.), Si and its oxides (SiO, etc.), tin, etc., and is not particularly limited. This embodiment is particularly suitable when a three-component three-component cathode active material is included.

[0055] The separator can be a microporous sheet or nonwoven fabric made of resin. In this embodiment, the electrode body is formed by stacking electrode plates (positive electrode plate and negative electrode plate) in the Y-axis direction. The electrode body may be of any form, such as a wound electrode body formed by winding electrode plates (positive electrode plate and negative electrode plate), a stacked electrode body formed by stacking multiple flat electrode plates, or a bellows-type electrode body in which the electrode plates are folded in a bellows shape.

[0056] The current collector is a conductive member (positive electrode current collector and negative electrode current collector) that is electrically connected to the electrode terminal 140 and the electrode body. The positive electrode current collector is made of aluminum or an aluminum alloy, similar to the positive electrode base layer of the positive electrode plate, and the negative electrode current collector is made of copper or a copper alloy, similar to the negative electrode base layer of the negative electrode plate.

[0057] [3. Description of the composition of the resin exterior body 300] Next, the configuration of the resin exterior 300 (resin tray 310 and retaining member 320) will be described in detail. Figure 4 is a perspective view showing the configuration of the resin tray 310 according to this embodiment. Figure 5 is a perspective view showing the configuration of the retaining member 320 according to this embodiment. Figure 5(a) is an enlarged perspective view of the retaining member 320 shown in Figure 2, and Figure 5(b) is a perspective view showing the configuration of the retaining member 320 shown in Figure 5(a) when viewed from diagonally below.

[0058] As shown in Figure 4, the resin tray 310 has a resin tray body 311, a first wall portion 312, a second wall portion 313, a pair of third wall portions 314, and a first partition portion 315.

[0059] The resin tray body 311 is a flat, rectangular portion that is parallel to the XY plane and extends in the Y-axis direction, on which the multiple energy storage elements 100 and multiple spacers 200 are placed, and is arranged in the Z-axis negative direction. The resin tray body 311 is a wall portion (bottom wall portion) that forms the bottom surface of the resin outer casing 300, and is positioned opposite and in contact with the bottom surface 113 of the container 110 of the energy storage element 100 in the Z-axis direction. The resin tray body 311 has protruding portions 311a that bulge out toward the bottom surface 113 at positions opposite to the bottom surface 113 of each energy storage element 100.

[0060] The first wall portion 312 is a long, flat wall portion that protrudes in the Z-axis direction from the X-axis positive end of the resin tray body 311, is parallel to the YZ plane and extends in the Y-axis direction, and is positioned opposite the energy storage element 100 in the X-axis direction (third direction). The first wall portion 312 is positioned opposite the short side 112 in the X-axis positive direction of the container 110 of the energy storage element 100 in the X-axis direction. The first wall portion 312 covers only the lower end (the end in the Z-axis negative direction) of the short side 112 of the container 110.

[0061] In the first wall portion 312, a pair of notches 312a are formed on the upper edge (the edge in the positive Z-axis direction). Each of the pair of notches 312a is a rectangular opening in plan view that is elongated in the Y-axis direction. The pair of notches 312a are formed in positions that do not include the Y-axis positive end, the Y-axis positive center, and the Y-axis negative end of the first wall portion 312. In each of the locations in the first wall portion 312 where the pair of notches 312a are not provided, a claw portion 312b is formed that protrudes in the positive X-axis direction, into which each locking piece 511a of the first support 510 is locked.

[0062] The second wall portion 313 is a long, flat wall portion that protrudes from the X-axis negative end of the resin tray body 311 in the Z-axis positive direction, is parallel to the YZ plane and extends in the Y-axis direction, and is positioned opposite the energy storage element 100 in the X-axis direction (third direction). The second wall portion 313 is positioned opposite the short side 112 of the container 110 of the energy storage element 100 in the X-axis direction. The second wall portion 313 covers only the lower end (Z-axis negative end) of the short side 112 of the container 110. The second wall portion 313 is positioned to sandwich the energy storage element 100 between the first wall portion 312 and the second wall portion 313 in the X-axis direction (third direction).

[0063] In the second wall portion 313, a pair of notches 313a are formed on the upper edge (edge ​​in the positive Z-axis direction). Each of the pair of notches 313a is a rectangular opening in plan view that is elongated in the Y-axis direction. The pair of notches 313a are formed in positions that do not include the Y-axis positive end, the Y-axis positive center, and the Y-axis negative end of the second wall portion 313. In each of the locations in the second wall portion 313 where the pair of notches 313a are not provided, a claw portion (not shown) protruding in the positive X-axis direction is formed, into which each locking piece 511a of the first support 510 is locked.

[0064] Figure 6 is a perspective view showing the locking state between the locking piece 511a and the claw portion 312b according to this embodiment. Although Figure 6 shows the locking state between the locking piece 511a and the claw portion 312b provided at the end in the negative Y-axis direction, the locking state is basically the same for other locking pieces 511a, other claw portions 312b, and the claw portion of the second wall portion 313.

[0065] As shown in Figure 6, the locking piece 511a has a locking opening 511c that is elongated in the Y-axis direction and has a rectangular shape in plan view. The claw portion 312b is positioned inside this locking opening 511c and is locked to the locking piece 511a by catching on the upper edge of the locking opening 511c. Here, the locking piece 511a is formed lower than the height of the end of the first wall portion 312 in the negative Y-axis direction (length in the Z-axis direction). This makes it possible to keep the locking piece 511a as small as possible while ensuring sufficient creepage distance between the locking piece 511a and the short side surface 112 of the energy storage element 100 corresponding to the locking piece 511a.

[0066] Similarly, the rib 511b of the first support 510 is formed lower than the height of the portion corresponding to the notch 312a of the first wall 312. This makes it possible to minimize the size of the rib 511b while still ensuring sufficient creepage distance between the rib 511b and the short side surface 112 of the energy storage element 100 corresponding to the rib 511b. In this way, the locking piece 511a and the rib 511b can be miniaturized, which in turn allows the first support 510 to be miniaturized, thereby reducing the amount of metal used.

[0067] As shown in Figure 4, the third wall portion 314 is a flat, rectangular wall portion that protrudes in the Z-axis direction from both ends of the resin tray body 311 in the Y-axis direction, is parallel to the XZ plane and extends in the X-axis direction, and is positioned opposite the energy storage element 100 in the Y-axis direction. The third wall portion 314 is positioned opposite the long side surface 111 of the container 110 of the energy storage element 100 at its end in the Y-axis direction.

[0068] The first partition portion 315 is a part that separates two adjacent energy storage elements 100. Specifically, the first partition portion 315 is a part that protrudes in a bulging manner from the resin tray body 311 in the Z-axis positive direction and extends in the X-axis direction. The first partition portion 315 is positioned between two adjacent energy storage elements 100 and in the Z-axis negative direction of the spacer 200, and is a base that supports the spacer 200 in the Z-axis direction (second direction). In this embodiment, a plurality of first partition portions 315 are arranged in the Y-axis direction to correspond to all spacers 210, and each first partition portion 315 supports each spacer 210 from the Z-axis negative direction. A first partition portion 315 that supports spacers 220 may also be provided.

[0069] As shown in Figure 5, the retaining member 320 has a retaining member body 321, a first wall portion 322, a second wall portion 323, and a second partition portion 324.

[0070] The retaining member body 321 is a plate-shaped and rectangular portion that is parallel to the XY plane and extends in the Y-axis direction, covering the multiple energy storage elements 100 and multiple spacers 200 in the Z-axis positive direction. The retaining member body 321 has multiple openings 321a and 321b. The openings 321a are rectangular through holes that are arranged side by side in the Y-axis direction at both ends of the retaining member body 321 in the X-axis direction and penetrate the retaining member body 321 in the Z-axis direction, with the busbar 400 positioned inside. The openings 321b are circular through holes that are arranged side by side in the Y-axis direction at the center of the retaining member body 321 in the X-axis direction and penetrate the retaining member body 321 in the Z-axis direction, through which the gas discharged from the gas discharge valve 131 of the energy storage element 100 passes. An elongated exhaust member 600 (see Figure 2), extending in the Y-axis direction, is attached to the central part of the retaining member body 321 in the X-axis direction, covering each opening 321b, and this exhaust member 600 forms a gas exhaust path. The exhaust member 600 is open at the bottom, and each opening 321b is located in this open portion. Therefore, the gas exhaust path is composed of the exhaust member 600 and the central part of the retaining member body 321 in the X-axis direction. The exhaust member 600 is pressed together with the retaining member 320 by the second support 520. In other words, the second support 520 is an example of a bracket that holds down the exhaust member 600.

[0071] The first wall portion 322 is a long, flat wall portion that protrudes from the X-axis positive end of the retaining member body 321 in the Z-axis negative direction (and Z-axis positive direction), is parallel to the YZ plane and extends in the Y-axis direction, and is positioned opposite the energy storage element 100 in the X-axis direction (third direction). The first wall portion 322 is positioned opposite the X-axis positive short side 112 of the container 110 of the energy storage element 100 in the X-axis direction. The first wall portion 322 covers only the upper end (Z-axis positive end) of the short side 112 of the container 110.

[0072] The second wall portion 323 is a long, flat wall portion that protrudes from the X-axis negative end of the retaining member body 321 in the Z-axis negative direction (and Z-axis positive direction), is parallel to the YZ plane and extends in the Y-axis direction, and is positioned opposite the energy storage element 100 in the X-axis direction (third direction). The second wall portion 323 is positioned opposite the short side 112 of the container 110 of the energy storage element 100 in the X-axis direction in the X-axis direction. The second wall portion 323 covers only the upper end (Z-axis positive end) of the short side 112 of the container 110. The second wall portion 323 is positioned to sandwich the energy storage element 100 between the first wall portion 322 and the second wall portion 323 in the X-axis direction (third direction).

[0073] The second partition portion 324 is a part that separates two adjacent energy storage elements 100. The second partition portion 324 is a flat, rectangular portion that protrudes from the main body of the retaining member 321 in the negative Z-axis direction and extends in the X-axis direction. The second partition portion 324 is positioned between two adjacent energy storage elements 100. In this embodiment, the second partition portion 324 is divided into three flat portions in the X-axis direction, but it may be continuously connected in the X-axis direction.

[0074] Figure 7 is a perspective view showing the resin casing 300 (resin tray 310 and retaining member 320) according to this embodiment assembled to a plurality of energy storage elements 100. As shown in Figure 7, the resin tray 310 of the resin casing 300 has a first wall portion 312 that covers only the lower end (end in the negative Z-axis direction) of the short side 112 of all containers 110. The retaining member 320 of the resin casing 300 has a first wall portion 322 that covers only the upper end (end in the positive Z-axis direction) of the short side 112 of all containers 110. Therefore, the central part of the short side 112 of all containers 110 in the Z-axis direction is exposed from the resin casing 300. In this way, the resin casing 300 has a shape that exposes a part of the short side 112 of the plurality of energy storage elements 100 in the Z-axis direction (second direction) and the entire part in the Y-axis direction. In Figure 7, the area exposed from the resin casing 300 on the short side 112 of all energy storage elements 100 is indicated by a dashed line L1. This area indicated by the dashed line L1 is exposed from the casing support 500 (first support 510 and second support 520) even when the casing support 500 is assembled, as shown in Figure 1. In this way, on the short side 112 of all energy storage elements 100, the entire area in the Y-axis direction at the center in the Z-axis direction is exposed from the resin casing 300 and the casing support 500, which allows for a larger exposed area of ​​each energy storage element 100. This makes it easier to dissipate the heat generated from the energy storage elements 100 during charging and discharging.

[0075] Here, considering the point of heat dissipation efficiency, the width in the Z-axis direction of the portion of the short side 112 of the energy storage element 100 that is exposed from the resin casing 300 should be 30% or more of the total length of the short side 112 in the Z-axis direction, more preferably 50% or more, and even more preferably 80% or more.

[0076] [4. Explanation of Effects] As a result of the above configuration, the energy storage device 1 according to the embodiment of the present invention provides the following effects. The resin casing 300 exposes at least a portion of the short sides 112 (sides) of at least two adjacent energy storage elements 100 in the Z-axis direction (second direction) and the entire Y-axis direction (first direction). Therefore, the exposed area of ​​the energy storage elements 100 can be increased for the energy storage device 1 as a whole. This makes it easier to dissipate the heat generated during charging and discharging, and suppresses the deterioration of the energy storage elements 100. Consequently, the reliability of the energy storage device 1 can be improved.

[0077] Furthermore, since the resin casing 300 exposes at least a portion of the short sides 112 of at least two adjacent energy storage elements 100 in the Z-axis direction, and the entire Y-axis direction, the amount of resin used in the energy storage device 1 as a whole can be reduced. If the amount of resin used is reduced, even if the energy storage device 1 catches fire, the spread of fire to other components (such as other energy storage devices adjacent to the energy storage device or other structures) caused by the resin can be suppressed. From this point of view as well, the reliability of the energy storage device 1 can be improved.

[0078] The resin casing 300 exposes at least a portion of the short sides 112 of the multiple energy storage elements 100 in the Z-axis direction and the entire Y-axis direction. This allows for a larger exposed area of ​​the energy storage elements 100 as a whole. This enhances the effect of suppressing the degradation of the energy storage elements 100. Furthermore, the amount of resin used in the energy storage device 1 as a whole can be reduced, thereby enhancing the effect of suppressing the spread of fire. As a result, the reliability of the energy storage device 1 can be further improved.

[0079] Even in a power storage device 1 in which multiple energy storage elements 100 are sandwiched between a resin tray 310 and a retaining member 320, at least a portion of the short sides 112 of at least two energy storage elements 100 in the Z-axis direction and the entire Y-axis direction can be continuously exposed. In other words, even in such a power storage device 1, the fire spread suppression effect and the degradation suppression effect can be achieved, and reliability can be improved.

[0080] The first partition 315 and the second partition 324 separate two adjacent energy storage elements 100, thereby allowing their positions to be restricted. For example, in the case of two energy storage elements 100 whose short sides 112 are continuously exposed in the Y-axis direction, it is difficult to restrict their positions on the short side 112 side. However, if partitions (first partition 315 and second partition 324) are provided on both the resin tray 310 and the retaining member 320, the positions of these two energy storage elements 100 can be reliably restricted.

[0081] Since the first support 510 and the second support 520 sandwich the resin tray 310 and the retaining member 320 in the alignment direction (Z-axis direction) and are joined to each other, the shape of the energy storage device 1 as a whole can be stabilized. Furthermore, since the resin tray 310 and the retaining member 320 are covered by the first support 510 and the second support 520, even if the resin tray 310 and the retaining member 320 burn, the first support 510 and the second support 520 can suppress the spread of fire to other components. This further enhances the reliability of the energy storage device 1.

[0082] As described above, in this embodiment, the amount of resin used is reduced, so the resin tray 310 and the retaining member 320 can be made smaller. Consequently, the molds used to manufacture the resin tray 310 and the retaining member 320 can also be made smaller, and moldability can be improved.

[0083] Since the gases emitted from multiple energy storage elements 100 can be collected and discharged by the exhaust member 600, the spread of fire from the resin casing 300 can be suppressed.

[0084] Since the retaining member 320 can be used as part of the gas exhaust path, there is no need to prepare a dedicated part, which reduces costs.

[0085] Since the second support 520 (bracket) holds down the exhaust member 600, the outflow of gas from the exhaust member 600 can be suppressed, and the spread of fire of the resin exterior 300 can be suppressed. In this embodiment, the case in which the exhaust member 600 is held down by the second support 520 is illustrated, but the exhaust member 600 may be held down by other members.

[0086] [5 Explanation of variations] Although the energy storage device 1 according to this embodiment has been described above, the present invention is not limited to the above embodiment. The embodiments disclosed herein are illustrative and not restrictive in all respects, and the scope of the present invention includes all modifications in the sense and scope equivalent to the claims.

[0087] In the above embodiment, an example was given in which the resin casing 300 has a resin tray 310 and a retaining member 320. However, the resin casing may have any shape as long as it exposes a part of the short side surface 112 of the plurality of energy storage elements 100 in the Z-axis direction (second direction) and the entire surface in the Y-axis direction. For example, the resin casing may be formed from a single box.

[0088] Figure 8A is a schematic plan view of a resin casing 300a according to Modification 1. As shown in Figure 8A, the resin casing 300a is formed from a rectangular box-shaped body with its ends in the Z-axis positive direction open. Multiple energy storage elements 100 arranged in the Y-axis direction are housed and held together inside this resin casing 300a. In the resin casing 300a, one rectangular opening 352a, which is elongated in the Y-axis direction, is formed in each of the pair of side walls 351a that form the long side surface. The opening 352a is formed to expose at least a portion of the short side surface 112 of the multiple energy storage elements 100 in the Z-axis direction, and the entire surface in the Y-axis direction. Specifically, the opening 352a continuously exposes the areas of all energy storage elements 100 except for both ends in the Z-axis direction.

[0089] Figure 8B is a schematic plan view of the resin casing 300b according to the modified example 2. As shown in Figure 8B, the resin casing 300b is formed from a rectangular box-shaped body with its ends in the Z-axis positive direction open. Multiple energy storage elements 100 arranged in the Y-axis direction are housed and held together inside this resin casing 300b. In the resin casing 300b, each of the pair of long side walls 351b has multiple rectangular openings 352b arranged along the Y-axis direction, which are elongated in the Z-axis direction. One opening 352a is formed to expose at least a portion of the short side 112 of two adjacent energy storage elements 100 in the Z-axis direction, and the entirety in the Y-axis direction. One opening 352b continuously exposes the areas of two adjacent energy storage elements 100 in the Z-axis direction, excluding both ends. Multiple openings 352b expose the entire short side 112 of all energy storage elements 100, at least a portion in the Z-axis direction and the entirety in the Y-axis direction. Note that three or more energy storage elements 100 may be exposed through a single opening 352b. Furthermore, at least one opening 352b is provided in the resin casing 300b. In the case of the resin casing exemplified in this modified example, a busbar frame separate from the resin casing may be placed at the Z-axis positive end of the resin casing.

[0090] (Other variations) In the above embodiment, the short side 112 of the energy storage element 100 is shown as being exposed from the resin casing 300 in the Y-axis direction at the center in the Z-axis direction. However, the short side 112 of the energy storage element 100 may also be exposed from the resin casing 300 in the Y-axis direction at least one end in the Z-axis direction and the other end.

[0091] In the above embodiment, the resin casing 300 (resin tray 310 and retaining member 320) is a tray and busbar frame that sandwiches a plurality of energy storage elements 100 and a plurality of spacers 200 in the Z-axis direction, but it is not limited to this. The retaining member 320 may be an insulating member for which electrical equipment (electrical components) such as a circuit board, relay, fuse, thermistor, or harness is placed, rather than a busbar frame.

[0092] In the above embodiment, an example was given in which partitions (first partition 315 and second partition 324) are provided on both the resin tray 310 and the retaining member 320. However, the partitions may be provided on only one of the resin tray 310 or the retaining member 320.

[0093] In the above embodiment, a case is illustrated in which a pair of notches 312a are formed in the first wall portion 312 of the resin tray 310, but the number of notches 312a is not limited to this. Furthermore, notches 312a may not be formed in the first wall portion 312.

[0094] The present invention also includes forms constructed by arbitrarily combining the components included in the above embodiments and their modified examples. [Industrial applicability]

[0095] This invention can be applied to energy storage devices equipped with energy storage elements such as lithium-ion secondary batteries. [Explanation of symbols]

[0096] 1. Energy storage device 10 Energy storage units 20 circuit board units 100 energy storage elements 110 Container 111 Long side 112 short side 113 Bottom 120 Container body 130 Lid 131 Gas discharge valve 140 Electrode terminal 200, 210, 220 spacers 300, 300a, 300b resin exterior body 310 Resin Tray 311 Resin tray body 311a Protrusion 312 First wall 312a Notch 312b Claw part 313 Second wall section 313a Notch 314 Third wall 315 First partition section 320 Retaining member 321 Retaining member body 321a, 321b opening 322 First wall part 323 Second wall section 324 Second partition section 351a, 351b side wall 352a, 352b opening 400 Bus Bar 410, 420 Cable 500 Outer casing support 510 First support 511 Bottom 511a Locking piece 511b Rib 511c Locking port 512, 513, 522, 523 Connection parts 520 Second support (bracket) 521 Top section 600 Exhaust components

Claims

1. Multiple energy storage elements arranged along the first direction, The system comprises a resin casing that holds the plurality of energy storage elements together, The resin casing has a shape that exposes at least a portion of the side surfaces of at least two adjacent energy storage elements among the plurality of energy storage elements in a second direction perpendicular to the first direction, and the entirety of the first direction. The aforementioned resin exterior body is A resin tray on which the plurality of energy storage elements are placed, The system includes a resin tray and a resin pressing member that sandwiches the plurality of energy storage elements between them. Energy storage device.

2. The aforementioned resin exterior body is The sides of the plurality of energy storage elements have a shape that exposes at least a portion in the second direction and the entirety in the first direction. The energy storage device according to claim 1.

3. At least one of the resin tray and the retaining member has a partition portion that separates the two energy storage elements. The energy storage device according to claim 1 or 2.

4. In the direction in which the resin tray and the pressing member are aligned, there is a pair of metal plates that sandwich the resin tray and the pressing member, The pair of metal plates are joined together such that at least a portion of the sides of the two adjacent energy storage elements in the second direction and the entire side in the first direction is exposed. The energy storage device according to any one of claims 1 to 3.

5. The retaining member is provided with an exhaust member that serves as an exhaust path for the gas discharged from the plurality of energy storage elements. The energy storage device according to any one of claims 1 to 4.

6. The aforementioned retaining member forms part of the exhaust path for the gas. The energy storage device according to claim 5.

7. The exhaust member has a bracket for holding it in place. The energy storage device according to claim 5 or 6.

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