Power storage device

Abstract

This power storage device comprises a power storage element and a spacer. The power storage element comprises a terminal, an electrode body, a current collector connected to the terminal and the electrode body, and a container in which the electrode body and the current collector are housed. Compared to the electrode body, the terminal is disposed in a second direction intersecting a first direction, which is the arrangement direction of the power storage element and the spacer. The current collector comprises a plate-like part facing in a third direction intersecting the first direction and the second direction. The spacer is disposed at a position not overlapping with the plate-like part as viewed in the first direction.

Description

Power storage device

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

[0002] Patent Document 1 discloses a secondary battery in which a collector terminal is arranged inside a battery case, the collector terminal having a substrate portion and a collector plate portion that is continuous with the substrate portion and extends in a direction perpendicular to the substrate portion, the substrate portion being connected to an external terminal, and the collector plate portion being connected to an electrode body.

[0003] Japanese Patent Application Laid-Open No. 2018-190546

[0004] In a conventional power storage device equipped with a secondary battery such as that disclosed in Patent Document 1, when an external impact is applied, the battery case of the secondary battery may be deformed, which may cause a short circuit between the battery case and the current collecting terminal. In particular, if the power storage device is equipped with a spacer on the side of the secondary battery, the spacer may press the battery case, causing a short circuit between the battery case and the current collecting terminal.

[0005] The present invention was made by the inventors of the present application by focusing on the above-mentioned problem, and has an object to provide an electricity storage device that can suppress the occurrence of short circuits.

[0006] A storage device according to one embodiment of the present invention comprises a storage element and a spacer, wherein the storage element comprises a terminal, an electrode body, a current collector connected to the terminal and the electrode body, and a container in which the electrode body and the current collector are housed, the terminal is arranged in a second direction intersecting a first direction in which the storage element and the spacer are arranged relative to the electrode body, the current collector has a plate-shaped portion facing a third direction intersecting the first direction and the second direction, and the spacer is arranged in a position that does not overlap with the plate-shaped portion when viewed from the first direction.

[0007] According to the electricity storage device of the present invention, the occurrence of a short circuit can be suppressed.

[0008] FIG. 1 is a perspective view showing the configuration of an energy storage device according to an embodiment. FIG. 2 is an exploded perspective view showing an energy storage element and a spacer included in the energy storage device according to an embodiment, in an exploded manner. FIG. 3 is a perspective view showing the internal configuration of a container of an energy storage element according to an embodiment, with a container body separated from the container. FIG. 4 is an exploded perspective view showing components other than the container body of an energy storage element according to an embodiment, in an exploded manner. FIG. 5 is a front view showing the positional relationship of each part of a spacer and an energy storage element according to an embodiment. FIG. 6 is a cross-sectional view showing the positional relationship of each part of a spacer and an energy storage element according to an embodiment. FIG. 7 is a top view showing the positional relationship of each part of a spacer and an energy storage element according to an embodiment. FIG. 8 is a perspective view showing the configuration of a current collector according to a first modified example of the embodiment.

[0009] (1) An energy storage device according to one aspect of the present invention comprises an energy storage element and a spacer, wherein the energy storage element comprises a terminal, an electrode body, a current collector connected to the terminal and the electrode body, and a container in which the electrode body and the current collector are housed, the terminal is arranged in a second direction intersecting a first direction in which the energy storage element and the spacer are arranged relative to the electrode body, the current collector has a plate-shaped portion facing a third direction intersecting the first direction and the second direction, and the spacer is arranged in a position that does not overlap with the plate-shaped portion when viewed from the first direction.

[0010] According to one aspect of the present invention, the energy storage device includes a current collector and a container that houses the current collector. The spacer is positioned so as not to overlap with the plate-shaped portion of the current collector when viewed from a first direction, which is the arrangement direction of the energy storage device and the spacer. By positioning the spacer so as not to overlap with the plate-shaped portion of the current collector, even if an external impact or the like is applied to the energy storage device and the spacer is pushed toward the energy storage device, the spacer prevents the container of the energy storage element from being pushed toward the plate-shaped portion. This prevents the container of the energy storage element from being deformed and causing a short circuit between the container and the plate-shaped portion. Therefore, the energy storage device can prevent the occurrence of a short circuit.

[0011] (2) In the energy storage device described in (1) above, the container may have a first wall portion arranged in the third direction of the electrode body, and the plate-shaped portion may be arranged opposite the first wall portion in the third direction.

[0012] According to the energy storage device described in (2) above, the plate-shaped portion of the current collector is arranged opposite the first wall portion of the container in the third direction, thereby increasing the width of the electrode body in the third direction and thereby achieving a high capacity.

[0013] (3) In the electricity storage device described in (1) or (2) above, the plate-shaped portion may be joined to the electrode body.

[0014] According to the electricity storage device described in (3) above, the plate-shaped portion of the current collector is joined to the electrode body, so that the current collector and the electrode body can be easily connected, and the electrode body can be stably held by the plate-shaped portion.

[0015] (4) In the energy storage device according to any one of (1) to (3) above, the plate-shaped portion may be arranged at a position overlapping a part of the electrode body when viewed from the first direction.

[0016] According to the electricity storage device described in (4) above, the plate-shaped portion of the current collector is disposed at a position overlapping a part of the electrode assembly when viewed from the first direction, which makes it easier for the plate-shaped portion to short-circuit with the container via the part of the electrode assembly. Therefore, it is highly effective to provide a configuration that can prevent a short circuit between the container and the plate-shaped portion.

[0017] (5) In the energy storage device described in any one of (1) to (4) above, the container may have a pair of second wall portions arranged on both sides of the electrode body in the first direction, and the length of the plate-shaped portion in the first direction may be 80% or more of the distance between the pair of second wall portions.

[0018] According to the electricity storage device described in (5) above, the length of the plate-shaped portion of the current collector is 80% or more of the distance between the pair of second walls of the container, which makes it easier for the plate-shaped portion to short-circuit with the container. Therefore, the configuration that can suppress a short circuit between the container and the plate-shaped portion is highly effective.

[0019] Hereinafter, with reference to the drawings, a description will be given of an energy storage device according to an embodiment of the present invention (including modifications thereof). The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, component placement and connection configurations, manufacturing processes, and the order of manufacturing processes shown in the following embodiments are examples and are not intended to limit the present invention. In each drawing, dimensions and the like are not strictly illustrated. In each drawing, the same or similar components are designated by the same reference numerals.

[0020] In the following description and drawings, the X-axis direction is defined as the direction in which the short sides of the container of the energy storage element face each other, the direction in which the pair of terminals (positive and negative electrodes; the same applies below) of the energy storage element are aligned, the direction in which the pair of current collectors are aligned, the direction in which the electrode assembly connection portions (plate-shaped portions) of the current collectors face, the plate thickness direction of the electrode assembly connection portions, the winding axis direction of the electrode assembly, or the longitudinal direction of the container or electrode assembly. The Y-axis direction is defined as the direction in which the multiple energy storage elements are aligned, the direction in which the energy storage elements and the spacer are aligned, the thickness direction of the energy storage element or the spacer, the direction in which the long sides of the container of the energy storage element face each other, the direction in which the two electrode assemblies are aligned, or the thickness direction of one electrode assembly. The Z-axis direction is defined as the direction in which the container body and the lid of the container of the energy storage element are aligned, the direction in which the electrode assemblies and the terminals are aligned, the direction in which the terminals protrude from the container, the direction in which the terminal connection portions of the current collectors face, the plate thickness direction of the terminal connection portions, or the up-down direction. The X-axis direction, Y-axis direction, and Z-axis direction intersect each other (orthogonal in this embodiment). Depending on the mode of use, the Z-axis direction may not be the up-down direction, but for the sake of convenience, the following description will be given assuming that the Z-axis direction is the up-down direction.

[0021] In the following description, the positive X-axis direction refers to the direction of the X-axis arrow, and the negative X-axis direction refers to the direction opposite to the positive X-axis direction. Simply referring to the X-axis direction refers to both or either of the positive X-axis direction and the negative X-axis direction. The same applies to the Y-axis and Z-axis directions. Hereinafter, the X-axis direction may be referred to as the third direction, the Y-axis direction as the first direction, and the Z-axis direction as the second direction. Expressions indicating relative directions or attitudes, such as parallel and perpendicular, may also include cases where the directions or attitudes are not strictly the same. Two directions being parallel (or perpendicular) not only means that the two directions are completely parallel (or perpendicular), but also means that the directions are substantially parallel (or perpendicular), i.e., there is a difference of a few percent. In the following description, the term "insulating" means "electrically insulating." An insulating material has a volume resistivity of 1×10 １０ It is preferable that the material be made of a material with a resistance of Ωm or more.

[0022] (Embodiment) [1 General Description of Energy Storage Device 1] First, a general description of the energy storage device 1 according to this embodiment will be given. Fig. 1 is a perspective view showing the configuration of the energy storage device 1 according to this embodiment. Fig. 1 shows the outline of a case 30 included in the energy storage device 1 with a broken line, and is a see-through view showing the inside of the case 30. Fig. 2 is an exploded perspective view showing energy storage elements 10 and spacers 20 included in the energy storage device 1 according to this embodiment.

[0023] The energy storage device 1 is a device that can charge electricity from an external source and discharge electricity to an external source, and in this embodiment has a substantially rectangular parallelepiped shape. The energy storage device 1 is a battery module (battery assembly) used for power storage, power supply, or the like. The energy storage device 1 is used as a battery for driving or starting the engine of a mobile object such as an automobile, a motorcycle, or an electric railway vehicle. Examples of such automobiles include electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs). The energy storage device 1 can also be used as a stationary battery for home or business use, etc.

[0024] As shown in FIGS. 1 and 2 , the energy storage device 1 includes a plurality of energy storage elements 10, a plurality of spacers 20, and a case 30. The energy storage device 1 also includes bus bars connected to terminals 200 (see FIG. 2 ) of the energy storage elements 10 to connect the energy storage elements 10 in series or in parallel, but these are not shown or described here. The bus bars may connect all of the energy storage elements 10 in series, or may connect some of the energy storage elements 10 in parallel and then connect them in series, or may connect all of the energy storage elements 10 in parallel. In addition to the above components, the energy storage device 1 may also include a bus bar frame that positions the bus bars, external terminals that are connected to external bus bars, etc., an exhaust unit that exhausts gases discharged from the energy storage elements 10, restraining members (end plates, side plates, etc.) that restrain the plurality of energy storage elements 10 and the plurality of spacers 20, and electrical devices such as a circuit board, fuses, relays, and connectors that monitor or control the charge and discharge states of the energy storage elements 10.

[0025] The energy storage element 10 is a secondary battery (single cell) capable of charging and discharging electricity, and more specifically, a non-aqueous electrolyte secondary battery such as a lithium-ion secondary battery. The energy storage element 10 has a rectangular parallelepiped shape (square or rectangular) that is long in the X-axis direction and flat in the Y-axis direction. In this embodiment, multiple (eight) energy storage elements 10 are arranged side by side in the Y-axis direction, but the number of arranged energy storage elements 10 is not particularly limited and may be just one. The size and shape of the energy storage element 10 are also not particularly limited and may not be long in the X-axis direction or flat in the Y-axis direction. The energy storage element 10 is not limited to a rectangular parallelepiped shape and may be a polygonal prism shape other than a rectangular parallelepiped, an elongated cylinder shape, an elliptical cylinder shape, a cylindrical shape, or the like. The energy storage element 10 is not limited to a non-aqueous electrolyte secondary battery and may be a secondary battery other than a non-aqueous electrolyte secondary battery or a capacitor. The energy storage element 10 may be a primary battery instead of a secondary battery. The energy storage element 10 may be a battery using a solid electrolyte. The configuration of the energy storage element 10 will be described in detail later.

[0026] The spacers 20 are members arranged alongside the energy storage elements 10 in the Y-axis direction. In this embodiment, the spacers 20 are flat, rectangular members that are elongated in the X-axis direction and parallel to the XZ plane. The spacers 20 are arranged in the positive or negative Y-axis direction of the energy storage elements 10 to absorb or suppress expansion of the energy storage elements 10 in the Y-axis direction. The spacers 20 are arranged between the energy storage elements 10 and other members (such as other energy storage elements 10 or the case 30) and also have the function of insulating and / or heat-insulating the energy storage elements 10 and other members. In this embodiment, spacers 20 are arranged on both sides of the multiple energy storage elements 10 in the Y-axis direction and between adjacent energy storage elements 10. Specifically, nine spacers 20 are arranged alternately with eight energy storage elements 10 in the Y-axis direction. The spacer 20 is disposed facing and in contact with a long side surface (a second wall portion 112 described later) of the container 100 included in the energy storage device 10. The spacer 20 may be fixed to the long side surface of the energy storage device 10 by adhesive bonding, welding, or the like.

[0027] The spacers 20 are 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), polyether ether ketone (PEEK), tetrafluoroethylene perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyethersulfone (PES), polyamide (PA), ABS resin, or composite materials thereof, or insulating materials such as metals with insulating coating, glass fiber, ceramics, or mica. All the spacers 20 may be formed from materials of the same material, or some of the spacers 20 may be formed from materials of different materials.

[0028] The case 30 is an exterior body disposed outside the plurality of energy storage elements 10 and the plurality of spacers 20. In the present embodiment, the case 30 is a substantially rectangular parallelepiped (box-shaped) container (module case) that houses the plurality of energy storage elements 10 and the plurality of spacers 20. The case 30 is disposed outside the plurality of energy storage elements 10 and the plurality of spacers 20, fixes the plurality of energy storage elements 10, etc. in predetermined positions, and protects them from impacts and the like. The case 30 is formed of an insulating material such as any of the resin materials that can be used for the spacers 20, and prevents the energy storage elements 10 from coming into contact with external metal members and the like. As long as the insulating properties of the energy storage elements 10 are maintained, the case 30 may be formed of a metal member such as aluminum, an aluminum alloy, stainless steel, iron, or plated steel sheet.

[0029] [2 Description of Energy Storage Element 10] Next, the configuration of the energy storage element 10 will be described in detail. A perspective view of the appearance of the energy storage element 10 is as shown in FIG. 2. FIG. 3 is a perspective view showing the internal configuration of the container 100 of the energy storage element 10 according to the present embodiment, with the container body 110 separated from the container 100. FIG. 4 is an exploded perspective view showing the components of the energy storage element 10 according to the present embodiment, other than the container body 110. Since the multiple energy storage elements 10 included in the energy storage device 1 all have the same configuration, FIGS. 3 and 4 show one energy storage element 10, and the configuration of one energy storage element 10 will be described in detail below.

[0030] As shown in FIGS. 3 and 4 , the energy storage element 10 includes a container 100, a pair of (positive and negative) terminals 200, and a pair of (positive and negative) upper gaskets 310. The energy storage element 10 further includes a pair of (positive and negative) lower gaskets 320, an electrode assembly 400, and a pair of (positive and negative) current collectors 500, all of which are housed within the container 100. An electrolyte (non-aqueous electrolyte) is sealed within the container 100, but is not shown. The type of electrolyte is not particularly limited as long as it does not impair the performance of the energy storage element 10, and various types can be selected. In addition to the above components, the energy storage element 10 may also include spacers arranged on the sides or below the electrode assembly 400, an insulating film that wraps the electrode assembly 400, and the like.

[0031] [2.1 Description of Container 100] The container 100 is a rectangular parallelepiped (square or box-shaped) case that includes a container body 110 with an opening facing in the positive direction of the Z axis, and a lid 120 that closes the opening of the container body 110. The container body 110 is a rectangular cylindrical member with a bottom that forms the main body of the container 100. The lid 120 is a member that forms the lid of the container 100, and is disposed in the positive direction of the Z axis of the container body 110. The lid 120 is a flat, rectangular wall that extends in the X axis direction.

[0032] The container body 110 has a pair of first wall portions 111 on both sides in the X-axis direction (short side surfaces), a pair of second wall portions 112 on both sides in the Y-axis direction (long side surfaces), and a third wall portion 113 on the surface in the negative Z-axis direction (bottom surface). The first wall portion 111 is a flat, rectangular wall portion (short side wall portion) extending in the Z-axis direction. The first wall portion 111 is adjacent to the second wall portion 112, the third wall portion 113, and the lid body 120, and has a smaller area than the second wall portion 112. The second wall portion 112 is a flat, rectangular wall portion (long side wall portion) extending in the X-axis direction. The second wall portion 112 is adjacent to the first wall portion 111, the third wall portion 113, and the lid body 120, and has a larger area than the first wall portion 111. The third wall portion 113 is a flat, rectangular wall portion (bottom wall portion) extending in the X-axis direction. The third wall portion 113 is disposed adjacent to the first wall portion 111 and the second wall portion 112. Depending on the shape of the container 100, the first wall portion 111 may be long in the Y-axis direction, the second wall portion 112 may be long in the Z-axis direction, or the third wall portion 113 may be long in the Y-axis direction. The first wall portion 111 may be a long side wall portion having a long side surface, and the second wall portion 112 may be a short side wall portion having a short side surface.

[0033] After the electrode assembly 400 and other components are housed inside the container body 110, the container body 110 and the lid 120 are joined by welding or the like, thereby sealing the interior of the container 100. The material of the container 100 (the container body 110 and the lid 120) is not particularly limited and may be a weldable (joinable) metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet, or a resin. The container 100 may be formed of a laminate film or the like composed of multiple layers including a metal layer and a resin layer. The container body 110 and the lid 120 may be formed of the same material or different materials. The container 100 (lid 120) may be provided with a liquid injection section for injecting an electrolyte into the container 100 during the manufacture of the energy storage device 10, and a gas exhaust valve for releasing pressure inside the container 100 if the pressure inside the container 100 increases excessively.

[0034] [2.2 Description of Terminal 200, Upper Gasket 310, and Lower Gasket 320] The terminals 200 are electrode terminals (positive and negative terminals) electrically connected to the electrode assembly 400 via the current collector 500. The terminals 200 are metal members for conducting electricity stored in the electrode assembly 400 to the external space of the energy storage element 10 and for introducing electricity into the internal space of the energy storage element 10 to store electricity in the electrode assembly 400. The terminals 200 are formed of a conductive member such as a metal, such as aluminum, an aluminum alloy, copper, or a copper alloy. The terminals 200 are connected (joined) to the current collector 500 by crimping, welding, or the like, and are attached to the lid 120. The terminals 200 are arranged so as to protrude in the positive Z-axis direction from the outer surface (the surface facing the positive Z-axis direction) of the lid 120. In this embodiment, terminal 200 is a welding terminal that is joined to an external conductive member such as a bus bar by welding, but terminal 200 may also be a bolt terminal that has a bolt portion formed with a male thread portion that protrudes in the positive direction of the Z axis and is joined to the conductive member by a bolt connection.

[0035] In this embodiment, two terminals 200 (a positive terminal 200 and a negative terminal 200) are arranged side by side in the X-axis direction. Hereinafter, one of the two terminals 200 (the terminal 200 located in the positive direction of the X-axis) will be referred to as terminal 210, and the other (the terminal 200 located in the negative direction of the X-axis) will be referred to as terminal 220. In this embodiment, terminal 210 is the positive terminal 200 (positive terminal), and terminal 220 is the negative terminal 200 (negative terminal).

[0036] The upper gasket 310 is a plate-like, rectangular gasket that is disposed between the lid 120 of the container 100 and the terminal 200, and is responsible for insulation and sealing between the lid 120 and the terminal 200. The lower gasket 320 is a plate-like, rectangular gasket that is disposed between the lid 120 and the current collector 500, and is responsible for insulation between the lid 120 and the current collector 500. The upper gasket 310 and the lower gasket 320 can be made of any suitable known material, such as an insulating material such as resin.

[0037] [2.3 Description of the Electrode Assembly 400] The electrode assembly 400 is an electricity storage element (power generation element) formed by stacking positive and negative electrode plates and a separator. The electrode assembly 400 is a wound electrode assembly formed by winding the positive and negative electrode plates and a separator around a winding axis extending in the X-axis direction. The winding axis is an imaginary axis that serves as the central axis when winding the positive and negative electrode plates, etc. In this embodiment, it is a straight line that passes through the center of the electrode assembly 400 and is parallel to the X-axis direction. In this embodiment, the electrode assembly 400 has an elongated shape extending in the X-axis direction and has a substantially oval cylindrical shape (an oval shape when viewed in the X-axis direction). The shape of the electrode assembly 400 is not particularly limited and may be a substantially cylindrical shape or a substantially elliptical cylindrical shape, and the length of the electrode assembly 400 in the X-axis direction is also not particularly limited. The electrode assembly 400 may be elongated in the Z-axis direction.

[0038] The positive electrode plate is an electrode plate in which a positive electrode active material layer is formed on the surface of a positive electrode current collector foil, which is a long, strip-shaped current collector foil (metal foil) made of a metal such as aluminum or an aluminum alloy. The negative electrode plate is an electrode plate in which a negative electrode active material layer is formed on the surface of a negative electrode current collector foil, which is a long, strip-shaped current collector foil (metal foil) made of a metal such as copper or a copper alloy. Any known material can be used for the positive electrode current collector foil and the negative electrode current collector foil, as long as it is stable against oxidation-reduction reactions during charging and discharging. Any known material can be used for the positive electrode active material used in the positive electrode active material layer and the negative electrode active material used in the negative electrode active material layer, as long as it is capable of absorbing and releasing charge-transporting ions.

[0039] The separator is a microporous insulating sheet made of resin or the like. Any known material can be used as the separator material as long as it does not impair the performance of the energy storage element 10. Examples of the separator include woven fabric, nonwoven fabric, and porous resin film.

[0040] The positive electrode plate has multiple tabs (positive electrode tabs) protruding on one side in the X-axis direction, and by winding the positive electrode plate, a positive electrode tab portion is formed in which the multiple tabs (positive electrode tabs) overlap. The negative electrode plate has multiple tabs (negative electrode tabs) protruding on the other side in the X-axis direction, and by winding the negative electrode plate, a negative electrode tab portion is formed in which the multiple tabs (negative electrode tabs) overlap. As a result, the electrode body 400 is configured to include an electrode body main body 410, a tab portion 420 protruding from the electrode body main body 410 in the positive direction of the X-axis, and a tab portion 430 protruding from the electrode body main body 410 in the negative direction of the X-axis. The electrode body main body 410 is the main body of the electrode body 400 and is an elongated cylindrical portion formed by winding the portions of the positive electrode plate and the negative electrode plate other than the tabs and a separator. The tab portion 420 and the tab portion 430 are portions that extend (protrude) outward from a part of the X-axis direction edge of the electrode body main body portion 410. In this embodiment, the tab portion 420 is a positive electrode tab portion, and the tab portion 430 is a negative electrode tab portion.

[0041] In this embodiment, the energy storage device 10 includes two electrode bodies 400 (electrode body 401 and electrode body 402). Both electrode bodies 401 and 402 are wound electrode bodies formed by winding a positive electrode plate, a negative electrode plate, and a separator. Therefore, the electrode body 401 includes an electrode body main body 411, a tab portion 421 protruding from the electrode body main body 411 in the positive direction of the X-axis, and a tab portion 431 protruding from the electrode body main body 411 in the negative direction of the X-axis. Similarly, the electrode body 402 includes an electrode body main body 412, a tab portion 422 protruding from the electrode body main body 412 in the positive direction of the X-axis, and a tab portion 432 protruding from the electrode body main body 412 in the negative direction of the X-axis. The tab portions 421 and 422 are positive electrode tab portions, and the tab portions 431 and 432 are negative electrode tab portions. The tab portions 420 (421 and 422) are connected (joined) to an electrode assembly connection portion 512 of the current collector 510, which will be described later. The tab portions 430 (431 and 432) are connected (joined) to an electrode assembly connection portion 522 of the current collector 520, which will be described later.

[0042] [2.4 Description of the Current Collector 500] The current collectors 500 are conductive current collecting members (positive electrode current collector and negative electrode current collector) that are arranged on both sides of the electrode body 400 in the X-axis direction and are connected (joined) to the electrode body 400 and the terminal 200, electrically connecting the electrode body 400 and the terminal 200. The current collector 500 has a shape in which a single plate-like member is bent, and is an L-shaped (inverted L-shaped) member when viewed in the Y-axis direction. The current collector 500 has a simple configuration and is easy to manufacture. Because the current collector 500 can be formed from a single plate-like member, there is no need to provide a separate lead, etc., and the number of parts can be reduced. Furthermore, by reducing the space occupied by the current collector 500 (space saving), the capacity of the energy storage element 10 can be improved.

[0043] In this embodiment, two current collectors 500 (a positive electrode current collector 500 and a negative electrode current collector 500) are arranged side by side in the X-axis direction. Hereinafter, one of the two current collectors 500 (the current collector 500 located in the positive direction of the X-axis) will be referred to as the current collector 510, and the other (the current collector 500 located in the negative direction of the X-axis) will be referred to as the current collector 520. In this embodiment, the current collector 510 is the positive electrode current collector 500 (positive electrode current collector), and the current collector 520 is the negative electrode current collector 500 (negative electrode current collector). The current collector 510 (positive electrode current collector) is formed of aluminum, an aluminum alloy, or the like, similar to the positive electrode current collector foil of the electrode assembly 400. The current collector 520 (negative electrode current collector) is formed of copper, a copper alloy, or the like, similar to the negative electrode current collector foil of the electrode assembly 400.

[0044] As shown in FIG. 4 , the current collector 510 includes a plate-shaped terminal connection portion 511 and a plate-shaped electrode assembly connection portion 512. The terminal connection portion 511 is a flat, rectangular portion parallel to the XY plane and is connected (joined) to the terminal 200 (terminal 210). The terminal connection portion 511 is arranged along the lid 120 and includes a through-hole 501 through which a shaft portion 201 of the terminal 210 passes. The shaft portion 201 is a rivet portion of the terminal 210 that extends in the negative Z-axis direction. The shaft portion 201 is inserted into the through-hole 311 of the upper gasket 310, the through-hole 121 of the lid 120, the through-hole 321 of the lower gasket 320, and the through-hole 501 of the terminal connection portion 511, and is crimped. As a result, the current collector 510 and the terminal 210 are fixed to the lid 120. The method for connecting (joining) the current collector 510 and the terminal 210 is not limited to crimping, and welding such as ultrasonic welding, laser welding, or resistance welding, or mechanical joining other than crimping such as screw joining, may also be used.

[0045] The electrode assembly connection portion 512 is a flat, rectangular portion parallel to the YZ plane, and is connected (joined) to the electrode assembly 400. The electrode assembly connection portion 512 extends in the negative Z-axis direction from the end of the terminal connection portion 511 in the positive X-axis direction along the first wall portion 111 of the container body 110 in the positive X-axis direction. As a result, the terminal connection portion 511 and the electrode assembly connection portion 512 are arranged in orientations facing different directions, and the electrode assembly connection portion 512 is arranged in an orientation facing the electrode assembly main bodies 411 and 412. The electrode assembly connection portion 512 is connected (joined) to the tab portion 420 of the electrode assembly 400. Specifically, the electrode assembly connection portion 512 is connected (joined) to the tab portion 421 of the electrode assembly 401 and the tab portion 422 of the electrode assembly 402. The electrode body connection portion 512 and the tab portion 420 (421 and 422) are connected (joined) by welding such as ultrasonic welding, laser welding, or resistance welding, or by mechanical joining such as crimping or screw joining.

[0046] Specifically, the tab portion 420 is bent toward the current collector 510, disposed on the outside of the current collector 510, and joined to the current collector 510. The tab portion 421 is bent in the positive Y-axis direction toward the electrode assembly connection portion 512, disposed in the positive X-axis direction of the electrode assembly connection portion 512, and joined to the electrode assembly connection portion 512. The tab portion 422 is bent in the negative Y-axis direction toward the electrode assembly connection portion 512, disposed in the positive X-axis direction of the electrode assembly connection portion 512, and joined to the electrode assembly connection portion 512. In this way, the tab portions 420 (421 and 422) are joined to the outside of the current collector 510 (electrode assembly connection portion 512) while wrapping around both sides of the current collector 510 (electrode assembly connection portion 512) in the Y-axis direction.

[0047] Similar to the current collector 510, the current collector 520 includes a plate-shaped terminal connection portion 521 and a plate-shaped electrode body connection portion 522. The terminal connection portion 521 is a flat, rectangular portion parallel to the XY plane, and is connected (joined) to the terminal 200 (terminal 220). The terminal connection portion 521 is disposed along the lid 120, and includes a through-hole 501 through which the shaft portion 201 of the terminal 220 passes. The configuration in which the terminal connection portion 521 is joined to the terminal 220 is similar to the configuration in which the terminal connection portion 511 is joined to the terminal 210, and therefore a detailed description thereof will be omitted.

[0048] The electrode assembly connection portion 522 is a flat, rectangular portion parallel to the YZ plane, and is connected (joined) to the electrode assembly 400. The electrode assembly connection portion 522 extends in the negative Z-axis direction from the end of the terminal connection portion 521 in the negative X-axis direction along the first wall portion 111 of the container body 110 in the negative X-axis direction. As a result, the terminal connection portion 521 and the electrode assembly connection portion 522 are arranged in orientations facing different directions, and the electrode assembly connection portion 522 is arranged in an orientation facing the electrode assembly main bodies 411 and 412. The electrode assembly connection portion 522 is connected (joined) to the tab portion 430 of the electrode assembly 400. Specifically, the electrode assembly connection portion 522 is connected (joined) to the tab portion 431 of the electrode assembly 401 and the tab portion 432 of the electrode assembly 402. The configuration in which the electrode body connection portion 522 and the tab portion 430 (431 and 432) are joined is similar to the configuration in which the electrode body connection portion 512 and the tab portion 420 (421 and 422) are joined, so detailed explanation will be omitted.

[0049] Specifically, the tab portion 430 is bent toward the current collector 520, disposed on the outside of the current collector 520, and joined to the current collector 520. The tab portion 431 is bent in the positive Y-axis direction toward the electrode assembly connection portion 522, disposed in the negative X-axis direction of the electrode assembly connection portion 522, and joined to the electrode assembly connection portion 522. The tab portion 432 is bent in the negative Y-axis direction toward the electrode assembly connection portion 522, disposed in the negative X-axis direction of the electrode assembly connection portion 522, and joined to the electrode assembly connection portion 522. In this way, the tab portions 430 (431 and 432) are joined to the outside of the current collector 520 (electrode assembly connection portion 522) while wrapping around both sides of the current collector 520 (electrode assembly connection portion 522) in the Y-axis direction.

[0050] [3 Description of Positional Relationships Between Spacer 20 and Each Part of Energy Storage Device 10] Next, the positional relationship between the spacer 20 and each part of the energy storage device 10 will be described in detail. FIG. 5 is a front view showing the positional relationship between the spacer 20 and each part of the energy storage device 10 according to this embodiment. FIG. 5 is a view from the negative Y-axis direction showing the state in which the spacer 20 is arranged on the energy storage device 10. FIG. 6 is a cross-sectional view showing the positional relationship between the spacer 20 and each part of the energy storage device 10 according to this embodiment. FIG. 6 is a view from the positive X-axis direction showing the state in which spacers 20 are arranged on both sides of one energy storage device 10, and shows a cross-section of the configuration of FIG. 5 cut along a plane parallel to the YZ plane including line VI-VI. FIG. 7 is a top view showing the positional relationship between the spacer 20 and each part of the energy storage device 10 according to this embodiment. FIG. 7 is a view from the positive Z-axis direction showing the state in which a plurality of energy storage devices 10 and a plurality of spacers 20 are arranged side by side.

[0051] Of the two current collectors 500, the current collector 510 (terminal connection portion 511 and electrode body connection portion 512) will be mainly described below, but the same applies to the current collector 520 (terminal connection portion 521 and electrode body connection portion 522). Of the two terminals 200, the terminal 210 will be mainly described, but the same applies to the terminal 220.

[0052] As shown in FIGS. 5 to 7 , in one energy storage element 10, the terminal 210 is disposed further from the electrode assembly 400 in the Z-axis direction (second direction) that intersects with the Y-axis direction (first direction), which is the arrangement direction of the energy storage elements 10 and the spacers 20. Specifically, the terminal 210 is disposed in the positive Z-axis direction of the electrode assembly 400. The first wall 111 of the container 100 is disposed in the X-axis direction of the electrode assembly 400 (a third direction that intersects with the first and second directions). A pair of first walls 111 are disposed on both sides of the electrode assembly 400 in the X-axis direction (third direction). The second wall 112 is disposed in the Y-axis direction (first direction) of the electrode assembly 400. A pair of second walls 112 are disposed on both sides of the electrode assembly 400 in the Y-axis direction (first direction). The third wall 113 and the lid 120 are disposed in the Z-axis direction (second direction) of the electrode assembly 400.

[0053] The terminal connection portion 511 of the current collector 510 faces the Z-axis direction (second direction). The electrode body connection portion 512 faces the X-axis direction (third direction). The terminal connection portion 511 is disposed opposite the lid body 120 in the Z-axis direction (second direction). The electrode body connection portion 512 is disposed opposite the first wall portion 111 in the X-axis direction (third direction). The electrode body connection portion 512 is disposed in a position overlapping with the tab portion 420 (421 and 422), which is part of the electrode body 400, when viewed from the Y-axis direction (first direction).

[0054] As described above, the current collector 510 has a shape formed by bending a single plate-like member, and therefore the electrode assembly connection portion 512 extends continuously in the Y-axis direction and the Z-axis direction. Therefore, the electrode assembly connection portion 512 is disposed near the inner surface of the container 100 (the inner surface of the second wall portion 112) in the Y-axis direction. Specifically, in the Y-axis direction (first direction), the length of the electrode assembly connection portion 512 (length A in FIG. 6 ) is 80% or more of the distance between the pair of second walls 112 (distance B in FIG. 6 ). When the length of the electrode assembly connection portion 512 in the Y-axis direction varies depending on the position in the Z-axis direction, the maximum length of the electrode assembly connection portion 512 in the Y-axis direction is defined as length A. Length A may be 85% or more of distance B, 90% or more of distance B, or 95% or more of distance B. Length A is less than 100% of distance B. The same applies to the electrode assembly connection portion 522 of the current collector 520.

[0055] In this configuration of the energy storage element 10, the spacer 20 is positioned so as not to overlap the electrode assembly connection portion 512 when viewed from the Y-axis direction (first direction) (see FIG. 5 , etc.). The spacer 20 is positioned in the negative X-axis direction relative to the electrode assembly connection portion 512. Specifically, the length of the spacer 20 in the X-axis direction is shorter than the distance between the electrode assembly connection portion 512 of the current collector 510 and the electrode assembly connection portion 522 of the current collector 520. Therefore, the spacer 20 is positioned between the electrode assembly connection portion 512 and the electrode assembly connection portion 522 when viewed from the Y-axis direction. Similarly, the length of the spacer 20 in the X-axis direction is shorter than the length of the electrode assembly main body portion 410 in the X-axis direction, and the spacer 20 is positioned at the center of the electrode assembly main body portion 410 in the X-axis direction. Therefore, the spacer 20 is positioned so as not to overlap the tab portions 420 (421 and 422) and tab portions 430 (431 and 432) of the electrode assembly 400 when viewed from the Y-axis direction.

[0056] Similarly, in the Z-axis direction, the spacer 20 is shorter than the length of the electrode body main body 410 in the Z-axis direction and is disposed in the center of the electrode body main body 410 in the Z-axis direction. Therefore, the spacer 20 is disposed in the negative Z-axis direction relative to the terminal connection portion 511 and is disposed in a position where it does not overlap with the terminal connection portion 511 when viewed from the Y-axis direction. In this way, the spacer 20 is disposed inside the outer edge of the electrode body main body 410 when viewed from the Y-axis direction. As a result, the spacer 20 is disposed in a position where it does not overlap with the entire current collector 510 when viewed from the Y-axis direction. The same is true for the current collector 520.

[0057] When viewed from the Y-axis direction (first direction), the ratio of the area of ​​the spacer 20 to the area of ​​the energy storage element 10 is preferably 70% or more and 90% or less, and more preferably 75% or more and 85% or less. When viewed from the Y-axis direction (first direction), the ratio of the area of ​​the spacer 20 to the area of ​​the electrode body 400 is preferably 80% or more and 120% or less, and more preferably 90% or more and 110% or less. By increasing the area of ​​the spacer 20 when viewed from the Y-axis direction (first direction), the electrode body 400 can be sufficiently pressed down by the spacer 20.

[0058] In this embodiment, the electrode assembly connection portion 512 of the current collector 510 is an example of a plate-shaped portion. The current collector 510 has a plate-shaped portion facing the third direction. The plate-shaped portion is arranged facing the first wall portion 111 in the third direction. The plate-shaped portion is joined to the electrode assembly 400. The plate-shaped portion is arranged in a position overlapping with a part of the electrode assembly 400 (tab portion 420) when viewed from the first direction. In the first direction, the length of the plate-shaped portion is 80% or more of the distance between the pair of second wall portions 112. The spacer 20 is arranged in a position not overlapping with the plate-shaped portion when viewed from the first direction. The same applies to the electrode assembly connection portion 522 of the current collector 520.

[0059] [4 Description of Effects] As described above, according to the energy storage device 1 according to the embodiment of the present invention, the energy storage element 10 includes the current collector 510 and the container 100 that houses the current collector 510. The spacer 20 is disposed in a position that does not overlap with the electrode assembly connection portion 512 (plate-shaped portion) of the current collector 510 when viewed from the Y-axis direction (first direction), which is the arrangement direction of the energy storage element 10 and the spacer 20. By disposing the spacer 20 in a position that does not overlap with the electrode assembly connection portion 512 (plate-shaped portion) of the current collector 510 in this manner, even if an external impact or the like is applied to the energy storage device 1 and the spacer 20 is pressed toward the energy storage element 10, the spacer 20 prevents the container 100 of the energy storage element 10 from being pressed toward the electrode assembly connection portion 512 (plate-shaped portion). This prevents the container 100 of the energy storage element 10 from deforming and causing a short circuit between the container 100 and the electrode assembly connection portion 512 (plate-shaped portion). Even when an insulating sheet is disposed between the container 100 and the electrode assembly connecting portion 512 (plate-shaped portion), there is a risk of a short circuit between the container 100 and the electrode assembly connecting portion 512 (plate-shaped portion) if the container 100 deforms and the insulating sheet breaks. However, in this embodiment, a short circuit between the container 100 and the electrode assembly connecting portion 512 (plate-shaped portion) can be prevented. Therefore, the energy storage device 1 can prevent the occurrence of a short circuit. The same applies to the current collector 520.

[0060] When viewed from the Y-axis direction (first direction), the ratio of the area of ​​the spacers 20 to the area of ​​the energy storage elements 10 is large, at 70% or more (more preferably 75% or more), or the ratio of the area of ​​the spacers 20 to the area of ​​the electrode assembly 400 is large, at 80% or more (more preferably 90% or more). This allows the spacers 20 to sufficiently press down on the electrode assembly 400.

[0061] By arranging the electrode body connection portion 512 (plate-shaped portion) of the current collector 510 opposite the first wall portion 111 of the container 100 in the X-axis direction (third direction), the width of the electrode body 400 in the X-axis direction (third direction) can be increased, thereby achieving a high capacity.

[0062] By joining the electrode assembly connecting portion 512 (plate-shaped portion) of the current collector 510 to the electrode assembly 400, the current collector 510 and the electrode assembly 400 can be easily connected, and the electrode assembly connecting portion 512 (plate-shaped portion) can stably hold the electrode assembly 400. The same applies to the current collector 520.

[0063] The electrode body connection portion 512 (plate-shaped portion) of the current collector 510 is positioned so as to overlap with the tab portion 420 (421 and 422) that is part of the electrode body 400 when viewed from the Y-axis direction (first direction). This makes it easier for the electrode body connection portion 512 (plate-shaped portion) to short-circuit with the container 100 via this part of the electrode body 400. For this reason, it is highly effective to have a configuration that can prevent a short circuit between the container 100 and the electrode body connection portion 512 (plate-shaped portion). The same applies to the current collector 520.

[0064] The length of the electrode assembly connection portion 512 (plate-shaped portion) of the current collector 510 is as large as 80% or more of the distance between the pair of second wall portions 112 of the container 100, making it easier for the electrode assembly connection portion 512 (plate-shaped portion) to short-circuit with the container 100. For this reason, it is highly effective to have a configuration that can prevent a short circuit between the container 100 and the electrode assembly connection portion 512 (plate-shaped portion). The same applies to the current collector 520.

[0065] [5. Description of Modifications] While the energy storage device 1 according to the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. The embodiment disclosed herein is an example in all respects, and the scope of the present invention includes all modifications within the meaning and scope of the claims.

[0066] (Variation 1) In the above embodiment, the current collector 500 of the energy storage element 10 has a shape formed by bending a single plate-like member, but this is not limited to this. In the current collector 510, the electrode assembly connection portion 512 may be a plate-like portion, and the shape thereof is not particularly limited. The same applies to the current collector 520. An example thereof will be described below. Figure 8 is a perspective view showing the configuration of a current collector 530 according to Variation 1 of this embodiment.

[0067] As shown in Fig. 8, the current collector 530 in this modification includes a terminal connection portion 531 and an electrode assembly connection portion 532. The terminal connection portion 531 has a configuration similar to that of the terminal connection portion 511 in the above embodiment. The electrode assembly connection portion 532 is a plate-shaped portion (comb-like portion) in which slits 532a are formed in the electrode assembly connection portion 512 in the above embodiment. In this modification, the electrode assembly connection portion 532 is formed with two slits 532a that extend in the positive Z-axis direction from its end in the negative Z-axis direction and penetrate in the X-axis direction. The tab portions 421 and 422 are inserted into and joined to these two slits 532a.

[0068] In this configuration, the length (length A1 in FIG. 8 ) of the electrode assembly connection portion 532 in the Y-axis direction (first direction) is 80% or more of the distance (distance B in FIG. 6 ) between the pair of second wall portions 112 of the container 100. The length A1 of the electrode assembly connection portion 532 in this modified example is the length from one edge to the other edge of the electrode assembly connection portion 532 in the Y-axis direction, and is the same as the length A of the electrode assembly connection portion 512 in the above embodiment. The spacer 20 is positioned so as not to overlap with the electrode assembly connection portion 532 when viewed from the Y-axis direction (first direction). In this modified example, the electrode assembly connection portion 532 is an example of a plate-shaped portion.

[0069] Other configurations of this modified example are the same as those of the above embodiment, and therefore description thereof will be omitted. This modified example can also achieve the same effects as those of the above embodiment. The same applies to the current collector 520. In this way, current collectors 500 of various shapes can be applied.

[0070] (Other Modifications) In the above embodiment, the electrode assembly connection portion 512 of the current collector 510 is a single flat plate-like portion, but it may be bent or curved. The electrode assembly connection portion 512 may be a lead. The electrode assembly connection portion 512 may be formed by connecting a plurality of plate-like members including leads or the like. The electrode assembly connection portion 512 may be formed by stacking a plurality of plate-like members. The same applies to the current collector 520.

[0071] In the above embodiment, the electrode assembly connection portion 512 of the current collector 510 is an example of a plate-shaped portion. However, a portion of the electrode assembly connection portion 512, rather than the entire portion, may be an example of a plate-shaped portion. The portion of the electrode assembly connection portion 512 that is not joined to the electrode assembly 400 may also be an example of a plate-shaped portion. If the width of the electrode assembly connection portion 512 in the Y-axis direction varies, the widest portion of the electrode assembly connection portion 512 may also be an example of a plate-shaped portion. The spacer 20 may be positioned so as not to overlap the widest portion (plate-shaped portion) of the electrode assembly connection portion 512 when viewed in the Y-axis direction. This also prevents a short circuit between the container 100 and the widest portion (plate-shaped portion) of the electrode assembly connection portion 512. The same applies to the current collector 520.

[0072] In the above embodiment, the electrode assembly connection portion 512 of the current collector 510 is only required to be oriented in the X-axis direction, and the position at which it is arranged is not particularly limited. The same applies to the current collector 520.

[0073] In the above embodiment, the length A of the electrode body connection portion 512 of the current collector 510 in the Y-axis direction is set to be 80% or more of the distance B between the pair of second wall portions 112, but it may be less than 80% of the distance B. The length A may be 70% or more of the distance B, 60% or more of the distance B, 50% or more of the distance B, or some other length. The same applies to the current collector 520.

[0074] In the above embodiment, the electrode body connection portion 512 of the current collector 510 is arranged at a position overlapping with the tab portion 420 as part of the electrode body 400 when viewed from the Y-axis direction, but it may also be arranged at a position overlapping with another part of the electrode body 400 (such as a part of the electrode body main body portion 410). The same applies to the current collector 520.

[0075] In the above embodiment, the electrode body 400 of the energy storage element 10 includes tab portions 420 (421, 422), and the tab portions 420 are connected (joined) to the current collector 510, but the electrode body 400 does not have to include tab portions 420. The end portion of the electrode body 400 in the positive direction of the X-axis (the portion that protrudes in the positive direction of the X-axis from the entire edge of the electrode body main body portion 410) may be connected (joined) to the current collector 510. The same applies to the tab portions 430 (431, 432).

[0076] In the above embodiment, the tab portions 420 (421, 422) are positioned and joined to the outside (positive direction of the X-axis) of the current collector 510 (electrode body connection portion 512), but they may also be positioned and joined to the inside (negative direction of the X-axis). The electrode body connection portion 512 does not have to be positioned so as to overlap with a part of the electrode body 400 (tab portion 420) when viewed from the Y-axis direction. The same applies to the tab portions 430 (431, 432) and the current collector 520.

[0077] In the above embodiment, the electrode body 400 (401, 402) is a wound electrode body whose winding axis is parallel to the lid body 120. However, the electrode body 400 may also be a wound electrode body whose winding axis is perpendicular to the lid body 120. The electrode body 400 may be a laminated (stacked) electrode body formed by stacking a plurality of flat electrode plates, or may be a bellows-type electrode body in which electrode plates are folded in a bellows shape, or may be an electrode body of another form.

[0078] In the above embodiment, the energy storage element 10 is provided with two electrode bodies 400 (401, 402), but the number of electrode bodies 400 is not particularly limited and may be one, or three or more.

[0079] In the above embodiment, the walls of the container 100 (the first wall 111, the second wall 112, etc.) are flat walls, but they may also be curved walls with at least a portion curved.

[0080] Any combination of the components included in the above-described embodiments and their modifications is also included within the scope of the present invention.

[0081] The present invention can be applied to an electricity storage device including an electricity storage element such as a lithium ion secondary battery.

[0082] REFERENCE SIGNS LIST 1 Energy storage device 10 Energy storage element 20 Spacer 30 Case 100 Container 110 Container body 111 First wall portion 112 Second wall portion 113 Third wall portion 120 Lid body 121, 311, 321, 501 Through hole 200, 210, 220 Terminal 201 Shaft portion 310 Upper gasket 320 Lower gasket 400, 401, 402 Electrode body 410, 411, 412 Electrode body main body portion 420, 421, 422, 430, 431, 432 Tab portion 500, 510, 520, 530 Current collector 511, 521, 531 Terminal connection portion 512, 522, 532 Electrode body connection portion 532a Slit

Claims

1. An energy storage device comprising: an energy storage element; and a spacer; the energy storage element comprises a terminal, an electrode body, a current collector connected to the terminal and the electrode body, and a container for accommodating the electrode body and the current collector; the terminal is arranged further than the electrode body in a second direction intersecting with a first direction in which the energy storage element and the spacer are arranged; the current collector has a plate-like portion facing a third direction intersecting with the first direction and the second direction; and the spacer is arranged in a position that does not overlap with the plate-like portion when viewed from the first direction.

2. The energy storage device according to claim 1, wherein the container has a first wall portion disposed in the third direction of the electrode body, and the plate-shaped portion is disposed opposite the first wall portion in the third direction.

3. The electricity storage device according to claim 1 or 2, wherein the plate-shaped portion is joined to the electrode body.

4. The energy storage device according to claim 1 or 2, wherein the plate-shaped portion is arranged at a position overlapping a part of the electrode body when viewed from the first direction.

5. The energy storage device according to claim 1 or 2, wherein the container has a pair of second wall portions arranged on both sides of the electrode body in the first direction, and the length of the plate-shaped portion in the first direction is 80% or more of the distance between the pair of second wall portions.

Images