Power storage device

Abstract

To provide a power storage device comprising an exterior film and enabling suppression of the corrosion of the exterior film.SOLUTION: A power storage device comprises a first power storage element 21a and a second storage element 21b which are laminated in a first direction. Each of the first power storage element and the second power storage element has an electrode body and an exterior film covering the electrode body. The exterior film has a main body film 212 facing the electrode body, and a protruding piece 241 protruding from an end edge of the main body film in a second direction Z crossing a first direction X. An insulator is provided between the protruding piece of the first power storage element and the protruding piece of the second power storage element.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] 2. Description of the Related Art Conventionally, in a battery pack, a plurality of pouch-type cells are accommodated in a battery pack housing in a stacked state (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-205247 A Summary of the Invention [Problem to be solved by the invention]

[0004] In this case, if the edges of two adjacent pouch-type cells in a stack of multiple pouch-type cells come into contact with each other, a short circuit may occur, which may cause corrosion of the exterior film of the pouch-type cell.

[0005] An object of the present invention is to provide an electricity storage device capable of suppressing corrosion of an exterior film. [Means for solving the problem]

[0006] One embodiment of the present invention relates to an energy storage device comprising a first energy storage element and a second energy storage element stacked in a first direction, wherein each of the first energy storage element and the second energy storage element comprises an electrode body and an exterior film covering the electrode body, wherein the exterior film comprises a main film facing the electrode body and a protruding piece protruding from an edge of the main film in a second direction intersecting the first direction, and an insulator is provided between the protruding piece of the first energy storage element and the protruding piece of the second energy storage element. Effect of the Invention

[0007] According to the present invention, it is possible to provide an electricity storage device capable of suppressing corrosion of an exterior film. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing the appearance of a power storage device according to an embodiment. [Diagram 2] FIG. 2 is an exploded perspective view showing each component of the electricity storage device according to the embodiment. [Diagram 3] FIG. 3 is a perspective view showing a plurality of energy storage elements and a plurality of spacers according to the embodiment, each separated from the others. [Figure 4] FIG. 4 is a side view showing a state in which a plurality of energy storage elements and a plurality of spacers according to the embodiment are integrated together. [Diagram 5] FIG. 5 is an enlarged side view showing a first projecting piece of a first energy storage element and a second projecting piece of a second energy storage element, as well as a spacer, in the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (1) An energy storage device according to one embodiment of the present invention is an energy storage device comprising a first energy storage element and a second energy storage element stacked in a first direction, each of the first energy storage element and the second energy storage element comprising an electrode body and an exterior film covering the electrode body, the exterior film comprising a main film facing the electrode body and a protruding piece protruding from an edge of the main film in a second direction intersecting the first direction, and an insulator is provided between the protruding piece of the first energy storage element and the protruding piece of the second energy storage element.

[0010] According to the energy storage device of the present invention, an insulator is provided between the protruding piece of the first energy storage element and the protruding piece of the second energy storage element, and the insulator prevents the protruding pieces from contacting each other (short-circuiting), thereby preventing corrosion of the exterior film caused by the short-circuiting of the protruding pieces.

[0011] (2) In the energy storage device described in (1) above, the protruding piece of the first energy storage element may be bent toward the insulator in a position that forms a space together with the main body film of the first energy storage element, and the protruding piece of the second energy storage element may be bent toward the insulator in a position that forms a space together with the main body film of the second energy storage element.

[0012] According to the energy storage device described in (2) above, since each protruding piece is bent toward the insulator in a position that forms a space together with each main film, even if the protruding piece receives an impact, the impact can be absorbed by the space, thereby improving the impact resistance of the first energy storage element and the second energy storage element.

[0013] (3) In the energy storage device described in (1) or (2) above, at least one of the protruding piece of the first energy storage element and the protruding piece of the second energy storage element may be adhered to the insulator.

[0014] According to the energy storage device described in (3) above, at least one of the protruding pieces of the first energy storage element and the protruding piece of the second energy storage element is bonded to the insulator, so that the protruding piece can be prevented from spreading, i.e., contact (short circuit) between the protruding pieces is reliably prevented.

[0015] (4) In the energy storage device described above in (3), the protruding piece of the first energy storage element may be adhered to the insulator in a state where a portion of the protruding piece is exposed.

[0016] According to the energy storage device described in (4) above, the insulator is adhered to the protruding piece of the first energy storage element while leaving a portion of the protruding piece exposed, thereby reducing the amount of insulator used compared to when the insulator is adhered to cover the entire protruding piece.

[0017] (5) In the energy storage device described above in (4), the protruding piece of the second energy storage element may be spaced apart from the insulator.

[0018] According to the energy storage device described in (5) above, since the protruding piece of the second energy storage element is separated from the insulator, an insulation distance between the protruding piece and the insulator can be secured, and thus contact (short circuit) between the protruding pieces is more reliably prevented.

[0019] (6) In the energy storage device described in (4) or (5) above, the main film may have an inclined portion at an end in the second direction, and the end of the protruding piece of the first energy storage element and the end of the insulator may have an overlapping region when viewed from the first direction, and the overlapping region may overlap the inclined portion when viewed from the first direction.

[0020] According to the energy storage device described in (6) above, the area where the end of the protruding piece of the first energy storage element and the end of the insulator overlap when viewed from the first direction overlaps the inclined portion when viewed from the first direction, thereby preventing the dimension of the energy storage device in the second direction from becoming large.

[0021] (7) In the energy storage device described in (6) above, the overlapping area may be arranged in the first direction between an end of the first energy storage element in the first direction and the edge.

[0022] According to the energy storage device described in (7) above, since the overlapping region is disposed between the end of the first energy storage element in the first direction and the edge of the main film, the protruding piece and the insulator do not protrude outward from the first energy storage element in the first direction, thereby making it possible to prevent the protruding piece of the second energy storage element from coming into contact with the protruding piece and the insulator of the first energy storage element.

[0023] (8) In the energy storage device described in any one of (1) to (7) above, the insulator may be at least a part of a spacer between the main body film of the first energy storage element and the main body film of the second energy storage element.

[0024] According to the electricity storage device described in (8) above, since the insulator is at least a part of the spacer, it is not necessary to provide a separate member dedicated to the insulator, which means that the number of parts can be reduced.

[0025] (Embodiment) Hereinafter, a description will be given of an energy storage device according to an embodiment (including modified examples) of the present invention with reference to the drawings. Note that the embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components shown in the following embodiments are merely 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 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 X-axis direction is defined as the arrangement direction of the main body and the outer lid in the exterior body of the energy storage device, or the arrangement direction of the multiple energy storage elements included in the energy storage device. The Y-axis direction is defined as the protruding direction of each lead terminal of the energy storage element. The Z-axis direction is defined as the arrangement direction of a pair of lead terminals included in the energy storage element, or the up-down direction. The X-axis direction is an example of a first direction, and the Z-axis direction is an example of a second direction. These X-axis direction, Y-axis direction, and Z-axis direction are directions that intersect with each other (orthogonal in the following embodiment). Note that, depending on the mode of use, the Z-axis direction may not be the up-down direction, but for convenience of explanation, the following description will be given assuming that the Z-axis direction is the up-down direction. In the following description, for example, the positive X-axis direction indicates the direction of the arrow on the X-axis, and the negative X-axis direction indicates the opposite side to the positive X-axis direction. The same applies to the Y-axis direction and the Z-axis direction. Furthermore, expressions indicating relative directions or attitudes, such as parallel and orthogonal, may also include cases where they are not strictly the directions or attitudes. For example, two directions being perpendicular to each other does not only mean that the two directions are completely perpendicular to each other, but also means that the two directions are substantially perpendicular to each other, that is, that there is a difference of, for example, about a few percent. In the following description, the term "insulation" means "electrical insulation".

[0027] [General description of the power storage device] First, an overall description of a power storage device 1 according to an embodiment will be given with reference to Fig. 1 and Fig. 2. Fig. 1 is a perspective view showing the external appearance of the power storage device 1 according to an embodiment. Fig. 2 is an exploded perspective view showing each component when the power storage device 1 according to the embodiment is disassembled.

[0028] The power storage device 1 is a device that can charge electricity from an external source and discharge electricity to the outside, and in this embodiment, has a substantially rectangular parallelepiped shape. For example, the power storage device 1 is a battery module (battery pack) used for power storage or power supply. Specifically, the power storage device 1 is used as a battery for driving or starting an engine of a moving body such as an automobile, a motorcycle, a watercraft, a ship, a snowmobile, an agricultural machine, a construction machine, an automatic guided vehicle (AGV: Automatic Guided Vehicle), or a railway vehicle for an electric railway. Examples of the above-mentioned 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 the above-mentioned railway vehicles for an electric railway include electric trains, monorails, linear motor cars, and hybrid trains equipped with both a diesel engine and an electric motor. The power storage device 1 can also be used as a stationary battery for home or business use.

[0029] 1 and 2, the energy storage device 1 includes an energy storage unit 20 and an exterior body 10 that houses the energy storage unit 20. The exterior body 10 includes a main body 11 that houses the energy storage unit 20, and an outer lid 12 that closes the main body 11.

[0030] The exterior body 10 is a rectangular (box-shaped) container (module case) that constitutes the exterior body of the energy storage device 1. In other words, the exterior body 10 is a member that fixes the energy storage unit 20 and the like in predetermined positions and protects these elements from impacts and the like.

[0031] The main body 11 is a rectangular cylindrical member with a bottom that is open in the positive direction of the X-axis, and the open portion is an opening 111. The opening 111 is substantially rectangular in a plan view (as viewed in the X-axis direction). In addition to the power storage unit 20, a plurality of bus bars (not shown) and fuses (not shown) held by the power storage unit 20 are housed inside the opening 111 of the main body 11.

[0032] The outer lid 12 is a member that closes the opening 111 of the main body 11, and is joined to the main body 11 in a state in which the opening 111 of the main body 11 is closed from the positive direction of the X-axis. A circuit board 35 is disposed at a position outside the opening 111 that corresponds to the outer lid 12. That is, the circuit board 35 is housed between the main body 11 and the outer lid 12. The outer lid 12 has a pair of external terminals 81 (positive and negative electrodes). The external terminals 81 are electrically connected to the multiple energy storage elements 21 included in the energy storage unit 20 via the bus bars, fuses, and circuit board 35. The energy storage device 1 charges with electricity from the outside and discharges electricity to the outside via the external terminals 81. The external terminals 81 are formed of a conductive member made of metal, such as a copper alloy such as brass, copper, aluminum, or an aluminum alloy.

[0033] Here, each bus bar is a plate-like member that electrically connects external terminals 81 and energy storage elements 21. Each bus bar is formed of a conductive member made of metal such as copper, a copper alloy, aluminum, or an aluminum alloy.

[0034] The fuse is a member that protects the circuit board 35, the plurality of energy storage elements 21, etc., from a current that is greater than or equal to the rated current. When a current that is greater than or equal to the rated current flows, the fuse melts to interrupt the flow of the current.

[0035] The circuit board 35 has a plurality of electric components (not shown), and these electric components form a detection circuit that detects the state (temperature, voltage, current, etc.) of each of the energy storage elements 21, a control circuit that controls charging and discharging, etc. It is sufficient for the circuit board 35 to have at least one of the detection circuit and the control circuit.

[0036] The main body 11 and the outer lid 12 of the exterior body 10 are formed of 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), polyether ether ketone (PEEK), tetrafluoroethylene perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyether sulfone (PES), polyamide (PA), ABS resin, or composite materials thereof, or metal or the like with an insulating coating. This prevents the energy storage element 21 and the like from coming into contact with external metal members and the like. Note that the exterior body 10 may be formed of a conductive material such as a metal as long as the electrical insulation of the energy storage element 21 and the like is maintained. The main body 11 and the outer lid 12 may be made of the same material or different materials.

[0037] [Energy storage unit] The electricity storage unit 20 includes a plurality of electricity storage elements 21, a holding portion 22, and a plurality of spacers 30 (see FIG. 3).

[0038] The electric storage element 21 is a secondary battery (single cell), and more specifically, a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. In this embodiment, the electric storage element 21 is a pouch-type electric storage element having a flat shape, and a plurality of (four in this embodiment) pouch-type electric storage elements 21 are arranged in the X-axis direction. The electric storage element 21 may be an electric storage element having a flat rectangular parallelepiped (corner), a cylindrical shape, an elongated cylindrical shape, an elliptical cylindrical shape, or the like, instead of a pouch-type electric storage element, and the size and shape are not limited. The number of the arranged electric storage elements 21 is also not particularly limited. The electric storage element 21 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 electric storage element 21 may be a primary battery that can use stored electricity without the user having to charge it, instead of a secondary battery. The plurality of energy storage elements 21 are arranged in the X-axis direction, and adjacent energy storage elements 21 may or may not be joined together with an adhesive or double-sided tape. Details of the energy storage elements 21 will be described later.

[0039] The holding portion 22 is a portion that holds the plurality of energy storage elements 21. The holding portion 22 has a first holding member 23 and a second holding member 24 that holds the plurality of energy storage elements 21 together with the first holding member 23. Specifically, the first holding member 23 is disposed in the negative X-axis direction of the plurality of energy storage elements 21, and is joined by an adhesive or double-sided tape to the energy storage element 21 disposed at the end of the plurality of energy storage elements 21 in the negative X-axis direction among the plurality of energy storage elements 21. The second holding member 24 is disposed in the positive X-axis direction of the plurality of energy storage elements 21, and is joined by an adhesive or double-sided tape to the energy storage element 21 disposed at the end of the plurality of energy storage elements 21 in the positive X-axis direction among the plurality of energy storage elements 21. As a result, the first holding member 23 and the second holding member 24 hold the plurality of energy storage elements 21 by sandwiching them in the X-axis direction. It is sufficient that at least one of the first holding member 23 and the second holding member 24 is joined to the energy storage element 21.

[0040] The first holding member 23 and the second holding member 24 are formed of an insulating material such as polycarbonate (PC), polypropylene (PP), polyethylene (PE), 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), polyether sulfone (PES), polyamide (PA), ABS resin, or a composite material thereof. As a result, the first holding member 23 and the second holding member 24 prevent the plurality of energy storage elements 21 from being electrically conductive with an external conductive member such as a metal member, but when such a need does not exist, the first holding member 23 and the second holding member 24 may be formed of an electrically conductive member such as a metal.

[0041] First retaining member 23 has flat plate portion 25 overlapping energy storage element 21 at the end portion in the negative X-axis direction, and bus bar support portion 26 extending in the positive X-axis direction from flat plate portion 25. Bus bar support portion 26 extends in the positive X-axis direction from corners of flat plate portion 25 in the negative Y-axis and negative Z-axis directions, and supports a bus bar (not shown).

[0042] Second holding member 24 has a board support portion 27 overlapping with power storage element 21 at the end portion in the positive direction of the X-axis, and a detection line support portion 28 extending in the negative direction of the X-axis from board support portion 27. Board support portion 27 supports circuit board 35, and has a surrounding wall 29 that surrounds circuit board 35. Board support portion 27 also supports a bus bar and a fuse (not shown).

[0043] Detection line support portion 28 is a portion that supports a plurality of detection lines 36 connected to circuit board 35 in order to detect the state (temperature, voltage, current, etc.) of each storage element 21. Detection line support portion 28 extends in the negative X-axis direction from the end portion of board support portion 27 in the negative Y-axis direction.

[0044] [Energy storage element] Next, details of the energy storage elements 21 will be described. Fig. 3 is a perspective view showing a plurality of energy storage elements 21 and a plurality of spacers 30 according to the embodiment, which are separated from each other. Fig. 4 is a side view showing a state in which the plurality of energy storage elements 21 and the plurality of spacers 30 according to the embodiment are integrated together.

[0045] The multiple energy storage elements 21 have the same basic structure, but their external shapes are partially different. Specifically, the odd-numbered energy storage elements 21 counting from the negative X-axis direction have partially different external shapes from the even-numbered energy storage elements 21 counting from the negative X-axis direction. In other words, the odd-numbered energy storage elements 21 have the same external shapes, and the even-numbered energy storage elements 21 have the same external shapes. In FIG. 3, each spacer 30 disposed between two adjacent energy storage elements 21 is also shown separately.

[0046] First, a basic structure of the energy storage element 21 will be described. The energy storage element 21 has an exterior film 210 and a pair of lead terminals 220 (positive and negative electrodes), and an electrode body 211 and an electrolyte (non-aqueous electrolyte: not shown) are contained inside the exterior film 210. There are no particular limitations on the type of electrolyte as long as it does not impair the performance of the energy storage element 21, and any known material can be used as appropriate.

[0047] The exterior film 210 is a sheet-like exterior body formed of a laminate film, and contains the electrode body 211, an electrolyte solution, etc., sealed in a reduced pressure state. The exterior film 210 is configured by stacking two rectangular laminate films in the X-axis direction. The two laminate films are joined (sealed) by heat welding or the like, sandwiching a pair of lead terminals 220 between them. In the two laminate films, the two laminate films are joined (sealed) by heat welding or the like at locations that do not correspond to the pair of lead terminals 220. The laminate film is a flexible film made of multiple layers including a metal layer such as aluminum and a resin layer such as polypropylene (PP) or polyethylene (PE), and the resin layer is disposed at the welding location (sealed portion). The exterior film 210 may be configured by forming one laminate film into a bag shape and joining the ends of the laminate film together by heat welding.

[0048] The lead terminal 220 is a conductive plate-like member (lead plate) electrically connected to the electrode body 211. The lead terminal 220 is disposed so as to be exposed from the exterior film 210 in a state in which it penetrates the exterior film 210. The lead terminal 220 is a tab portion protruding from one end of the energy storage element 21. In this embodiment, a pair of lead terminals 220 arranged in the Z-axis direction are disposed so as to protrude in the Y-axis negative direction from an end of the exterior film 210 in the Y-axis negative direction. Specifically, the positive electrode lead terminal 220 is a lead terminal electrically connected to the positive electrode plate of the electrode body 211, and the negative electrode lead terminal 220 is a lead terminal electrically connected to the negative electrode plate of the electrode body 211. In other words, the lead terminal 220 is a metal electrode terminal for guiding electricity stored in the electrode body 211 to the external space of the energy storage element 21 and for introducing electricity into the internal space of the energy storage element 21 in order to store electricity in the electrode body 211. The lead terminal 220 is made of aluminum, an aluminum alloy, copper, a copper alloy, or the like.

[0049] The electrode body 211 is an electricity storage element (power generation element) formed by stacking a positive electrode plate, a negative electrode plate, and a separator. The positive electrode plate is a positive electrode active material layer formed on a current collector foil made of a metal such as aluminum or an aluminum alloy. The negative electrode plate is a negative electrode active material layer formed on a current collector foil made of a metal such as copper or a copper alloy. As 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 can absorb and release lithium ions. The separator can be a microporous sheet or nonwoven fabric made of resin. In this embodiment, the electrode body 211 is formed by stacking electrode plates (positive electrode plate and negative electrode plate) in the X-axis direction. The electrode body 211 may be an electrode body of any shape, such as a wound type electrode body formed by winding electrode plates (positive and negative electrode plates), a laminated type (stack type) electrode body formed by stacking a plurality of flat electrode plates, or a bellows type electrode body in which electrode plates are folded in a bellows shape.

[0050] Next, the difference between the odd-numbered storage elements 21 and the even-numbered storage elements 21 will be described. As a common configuration between the odd-numbered storage elements 21 and the even-numbered storage elements 21, the exterior film 210 has a main film 212 overlapping the electrode body 211 and a frame portion 213 protruding outward from the entire periphery of the main film 212. The main film 212 overlaps each side surface of the electrode body 211. Both ends of the main film 212 in the Z-axis direction are inclined portions 250 that are tapered (see FIG. 4). In other words, both ends of the main film 212 in the Z-axis direction are inclined portions 250 that are inclined such that the width in the X-axis direction becomes smaller toward the frame portion 213. Both ends of the main film 212 in the Y-axis direction may also be inclined portions that are tapered. In other words, both ends of main film 212 in the Y-axis direction are inclined portions that are inclined so that the width in the X-axis direction becomes smaller toward frame portion 213.

[0051] Frame portion 213 is a sheet-like portion in which two laminate films are overlapped, and is formed into a rectangular frame shape when viewed from the X-axis direction. A pair of lead terminals 220 protrude in the negative Y-axis direction from a first side 214, which is an edge of frame portion 213 in the negative Y-axis direction, and are bent in the X-axis direction so as to be in opposite directions. Each lead terminal 220 is bent in the vicinity of first side 214 of exterior film 210, and a portion of each lead terminal 220 that is farther from main body film 212 based on the bending position is referred to as a tip portion 230.

[0052] Here, in the odd-numbered energy storage elements 21, the tip 231 of the lead terminal 221 in the positive direction of the Z axis is bent in the negative direction of the X axis, and the tip 232 of the lead terminal 222 in the negative direction of the Z axis is bent in the positive direction of the X axis. In contrast, in the even-numbered energy storage elements 21, the tip 231 of the lead terminal 221 in the positive direction of the Z axis is bent in the positive direction of the X axis, and the tip 232 of the lead terminal 222 in the negative direction of the Z axis is bent in the negative direction of the X axis.

[0053] A common configuration between the odd-numbered energy storage elements 21 and the even-numbered energy storage elements 21 is that, of the frame portion 213, the portions that sandwich the main film 212 in the Y-axis direction are formed flat, whereas the portions that sandwich the main film 212 in the Z-axis direction are folded. Specifically, of the frame portion 213, the portions that sandwich the main film 212 in the Z-axis direction are a pair of protruding pieces 240 that protrude from edges of the main film 212 in the Z-axis direction.

[0054] 4, a pair of protruding pieces 240 protrude in the Z-axis direction and are bent in the X-axis direction so as to be in opposite directions. Here, in the odd-numbered energy storage elements 21, the protruding piece 241 in the positive Z-axis direction is bent in the positive X-axis direction, and the protruding piece 242 in the negative Z-axis direction is bent in the negative X-axis direction. In contrast, in the even-numbered energy storage elements 21, the protruding piece 241 in the positive Z-axis direction is bent in the negative X-axis direction, and the protruding piece 242 in the negative Z-axis direction is bent in the positive X-axis direction.

[0055] The lead terminals 220 of each energy storage element 21 are joined to the lead terminals 220 or bus bars of the other energy storage elements 21. Specifically, the lead terminal 221 of the first energy storage element 21 has a tip portion 231 welded to a bus bar (not shown). The lead terminals 222 of the first energy storage element 21 and the lead terminals 222 of the second energy storage element 21 are welded to each other at their tip portions 232. The lead terminals 221 of the second energy storage element 21 and the lead terminals 221 of the third energy storage element 21 are welded to each other at their tip portions 231. The lead terminals 222 of the third energy storage element 21 and the lead terminals 222 of the fourth energy storage element 21 are welded to each other at their tip portions 232. The lead terminals 221 of the fourth energy storage element 21 have a tip portion 231 welded to another bus bar (not shown).

[0056] As shown in FIG. 3, a spacer 30 is disposed between a pair of adjacent energy storage elements 21. The spacer 30 is an insulating double-sided tape for joining the pair of adjacent energy storage elements 21. The insulating property of the spacer 30 can be expressed in other words as the volume resistivity of the spacer 30. The volume resistivity of the spacer 30 can be measured in accordance with JIS K6911:2006. The volume resistivity of the spacer 30 is 1×10 6 Ω·m or more is preferable, and 1×10 7 Ω·m or more is preferable, and 1×10 8It is more preferable that the resistance is Ω·m or more. Specifically, the spacer 30 has a sheet body made of the insulating material described above and a pair of adhesive layers formed on both sides of the sheet body. Although the spacer 30 can ensure a certain level of insulation by the sheet body even if each adhesive layer does not have insulating properties, it is preferable that each adhesive layer has insulating properties. The spacer 30 has a rectangular shape in a plan view and is attached to the main film 212 of a pair of adjacent storage elements 21 in an overlapping manner. One end of the spacer 30 in the Z-axis direction protrudes from the main film 212. Specifically, in the spacer 30 disposed between the first storage element 21 and the second storage element 21, the end in the Z-axis positive direction protrudes from the main film 212 of each storage element 21. In the spacer 30 disposed between the second storage element 21 and the third storage element 21, the end in the Z-axis negative direction protrudes from the main film 212 of each storage element 21. Spacer 30 disposed between third energy storage element 21 and fourth energy storage element 21 has an end in the positive Z-axis direction protruding from main body film 212 of each energy storage element 21 .

[0057] [Positional relationship between protruding piece and spacer] Next, the positional relationship between each protruding piece 241 and the spacer 30 will be described in detail using examples of the first and second energy storage elements 21 and the spacer 30 therebetween. Here, the first energy storage element 21 will be referred to as the first energy storage element 21a, and the protruding piece 241 of the first energy storage element 21 will be referred to as the first protruding piece 241a. Similarly, the second energy storage element 21 will be referred to as the second energy storage element 21b, and the protruding piece 241 of the second energy storage element 21 will be referred to as the second protruding piece 241b.

[0058] Fig. 5 is an enlarged side view showing first protruding piece 241a of first energy storage element 21a and second protruding piece 241b of second energy storage element 21b according to the embodiment, and spacer 30. As shown in Fig. 5, end 301 of spacer 30 in the positive direction on the Z axis protrudes in the positive direction on the Z axis from between main body film 212 of first energy storage element 21a and main body film 212 of second energy storage element 21b, and is disposed between first protruding piece 241a and second protruding piece 241b.

[0059] The first protruding piece 241a is bent in the positive direction of the X-axis as a whole. Specifically, the first protruding piece 241a is bent toward the spacer 30 in a position that forms a space s1 together with the main body film 212 of the first energy storage element 21a. Therefore, the end 243a of the first protruding piece 241a faces the negative direction of the Z-axis. Although the end 243a of the first protruding piece 241a is bonded to the end 301 of the spacer 30, the base is not bonded to the end 301 of the spacer 30 and is exposed. The end 301 of the spacer 30 is inclined in the negative direction of the X-axis by being bonded to the end 243a of the first protruding piece 241a.

[0060] The second protruding piece 241b is bent in the negative direction of the X-axis as a whole. Specifically, the second protruding piece 241b is bent toward the spacer 30 in a position that forms a space s2 together with the main body film 212 of the second energy storage element 21b. Therefore, the end 243b of the second protruding piece 241b faces in the negative direction of the Z-axis. The end 243b of the second protruding piece 241b is not bonded to the end 301 of the spacer 30 and is separated from the spacer 30.

[0061] Here, the end 243a of the first protruding piece 241a and the end 301 of the spacer 30 have an overlapping region R1 when viewed from the X-axis direction. Region R1 overlaps with the inclined portion 250 of the main body film 212 when viewed from the X-axis direction. Since region R1 overlaps with the inclined portion 250 of the main body film 212 when viewed from the X-axis direction in this manner, it is possible to prevent region R1 from protruding in the Z-axis direction. In other words, it is possible to prevent the dimension of the power storage device 1 in the Z-axis direction from becoming large.

[0062] Furthermore, region R1 is disposed in the X-axis direction between the end of first energy storage element 21a in the X-axis positive direction and the edge of main film 212 in the Z-axis positive direction (within interval i shown in FIG. 5 ). This prevents first protruding piece 241a and spacer 30 from protruding outward from first energy storage element 21a in the X-axis direction, thereby preventing second protruding piece 241b of second energy storage element 21b from contacting first protruding piece 241a and spacer 30.

[0063] [Effects, etc.] As described above, according to the present embodiment, insulating spacer 30 is provided between first protruding piece 241a of first energy storage element 21a and second protruding piece 241b of second energy storage element 21b, and thus contact (short circuit) between first protruding piece 241a and second protruding piece 241b is suppressed by spacer 30. Therefore, corrosion of exterior film 210 caused by a short circuit between first protruding piece 241a and second protruding piece 241b can be suppressed.

[0064] Since first protruding piece 241a and second protruding piece 241b are bent toward spacer 30 in a position that forms spaces s1 and s2 together with main body film 212, even if first protruding piece 241a and second protruding piece 241b receive an impact, the impact can be absorbed by spaces s1 and s2. This can improve the impact resistance of first energy storage element 21a and second energy storage element 21b.

[0065] For example, if first protruding piece 241a is bent so as to be in close contact with inclined portion 250 of main film 212, the bent portion of first protruding piece 241a will be bent sharply, which may cause excessive stress. However, if first protruding piece 241a is bent in a manner that forms space s1 as described above, the bent portion will be gentler, and stress can be alleviated. The same applies to second protruding piece 241b.

[0066] Since first protruding piece 241a of first energy storage element 21a is bonded to spacer 30, it is possible to prevent first protruding piece 241a from spreading out. In other words, contact (short circuit) between first protruding piece 241a and second protruding piece 241b is reliably prevented.

[0067] Since the spacer 30 is adhered to the first protruding piece 241a of the first storage element 21a while leaving a portion of the first protruding piece 241a exposed, the amount of spacer 30 used can be reduced compared to when the spacer 30 is adhered while covering the entire first protruding piece 241a.

[0068] Since second protruding piece 241b of second energy storage element 21b is separated from spacer 30, it is possible to ensure an insulation distance between second protruding piece 241b and spacer 30. This more reliably prevents contact (short circuit) between first protruding piece 241a and second protruding piece 241b.

[0069] The region R1 where the end 243a of the first protruding piece 241a of the first energy storage element 21a and the end 301 of the spacer 30 overlap when viewed from the X-axis direction (first direction), overlaps the inclined portion 250 when viewed from the X-axis direction, thereby preventing the dimension of the energy storage device 1 in the Z-axis direction from becoming larger.

[0070] Since region R1 is disposed between the end of first energy storage element 21a in the X-axis direction and the edge of main film 212, first protruding piece 241a and spacer 30 do not protrude outwardly of first energy storage element 21a in the X-axis direction. This makes it possible to prevent second protruding piece 241b of second energy storage element 21b from coming into contact with first protruding piece 241a and spacer 30 of first energy storage element 21a.

[0071] Since at least a portion of the spacer 30 is an insulator disposed between the first protruding piece 241a and the second protruding piece 241b, it is not necessary to provide a separate member dedicated to the insulator, which means that the number of parts can be reduced.

[0072] (others) Although the power storage device according to the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. In other words, the embodiment disclosed here is illustrative and not restrictive in all respects, and the scope of the present invention includes all modifications within the meaning and scope of the claims.

[0073] For example, in the above embodiment, the exterior film 210 is rectangular when viewed from the X-axis direction, but the exterior film may have any outer shape. Other outer shapes of the exterior film include polygonal shapes other than rectangular, oval shapes, ellipses, circles, and the like.

[0074] In the above embodiment, the first protruding piece 241a is folded in a position that forms the space s1 together with the main film 212, but the first protruding piece may be folded in a position that does not form a space. The same applies to the second protruding piece.

[0075] In the above embodiment, the second protruding piece 241b is separated from the spacer 30, but the second protruding piece may be bonded to the spacer. In this case, the second protruding piece can be prevented from spreading. Furthermore, both the first protruding piece and the second protruding piece do not have to be bonded to the spacer. In other words, both the first protruding piece and the second protruding piece may simply be in contact with the spacer, or may be separated from the spacer.

[0076] In the above embodiment, a case has been illustrated in which the first protruding piece 241a is adhered to the spacer 30 in a partially exposed state, but the first protruding piece may be entirely covered by the spacer and adhered thereto.

[0077] In the above embodiment, the spacer 30 is illustrated as an example of the insulator disposed between the first projecting piece 241a and the second projecting piece 241b, but the insulator may be an insulating member separate from the spacer.

[0078] Any combination of the components included in the embodiments and their modifications is also included within the scope of the present invention. [Industrial Applicability]

[0079] The present invention can be applied to an electricity storage device including an electricity storage element such as a lithium ion secondary battery. [Explanation of symbols]

[0080] 1. Energy storage device 10 Exterior body 11 Main body 12 Outer lid 20 Energy Storage Unit 21 Energy storage element 21a First storage element 21b Second storage element 22 Holding part 23 First retaining member 24 Second retaining member 25 Flat plate part 26 Busbar support 27 Substrate support 28 Detection line support part 29 Enclosure Wall 30 Spacer (insulator) 35 Circuit Board 36 Detection Line 81 External terminal 111 Opening 210 Exterior film 211 Electrode body 212 Main Film 213 Frame 214 First Side 220, 221, 222 Lead terminals 230, 231, 232 Tip 240, 241, 242 Projecting piece 241a First protruding piece 241b Second protruding piece 243a, 243b, 301 ends 250 Inclined section i Interval R1 area s1, s2 space

Claims

1. A power storage device including a first power storage element and a second power storage element stacked in a first direction, Each of the first storage element and the second storage element is An electrode body; An exterior film covering the electrode body, The exterior film is A main body film facing the electrode body; a protruding piece protruding from an edge of the main film in a second direction intersecting the first direction; an insulator is provided between the protruding piece of the first storage element and the protruding piece of the second storage element; Energy storage device.

2. the protruding piece of the first storage element is bent toward the insulator in a position to form a space together with the main body film of the first storage element, The protruding piece of the second storage element is bent toward the insulator in a position where a space is formed together with the main body film of the second storage element. The power storage device according to claim 1 .

3. At least one of the protruding piece of the first storage element and the protruding piece of the second storage element is adhered to the insulator. The power storage device according to claim 1 or 2.

4. The protruding piece of the first storage element is adhered to the insulator with a portion of the protruding piece being exposed. The power storage device according to claim 3 .

5. The protruding piece of the second storage element is spaced apart from the insulator. The power storage device according to claim 4.

6. The main film has an inclined portion at an end portion in the second direction, an end of the protruding piece of the first storage element and an end of the insulator have an overlapping region when viewed from the first direction, The overlapping region overlaps with the inclined portion when viewed from the first direction. The power storage device according to claim 4.

7. The overlapping region is disposed in the first direction between an end portion of the first storage element in the first direction and the edge. The power storage device according to claim 6.

8. The insulator is at least a part of a spacer between the body film of the first storage element and the body film of the second storage element. The power storage device according to claim 1 or 2.

Images