Energy storage element

Abstract

To provide a power storage element whose size can be reduced or whose capacity can be increased.SOLUTION: A power storage element comprises: a plurality of electrode bodies (electrode bodies 600 and 700) which are aligned in a first direction; collectors 500 which are connected to ends in a second direction perpendicular to the first direction of the plurality of electrode bodies; electrode terminals 200 which are disposed in a third direction perpendicular to the first direction and the second direction of the plurality of electrode bodies, and which are connected to the collectors 500; and a spacer 800 which is disposed between two of the plurality of electrode bodies 600 and 700. The spacer 800 is located at such a position that its both ends do not protrude from at least one of the plurality of electrode bodies in the third direction.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an energy storage element including an electrode body, a current collector, and an electrode terminal. [Background technology]

[0002] Conventionally, in an energy storage element including an electrode assembly, a current collector, and an electrode terminal, a configuration in which the current collector is connected to the lateral end of the electrode assembly and the electrode terminal is disposed above the electrode assembly has been known. For example, Patent Document 1 discloses a secondary battery (energy storage element) in which current collector plates (current collectors) are connected to the left and right end of an electrode assembly (electrode assembly) and external terminals (electrode terminals) are disposed above the electrode assembly. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2017 / 056733 Summary of the Invention [Problem to be solved by the invention]

[0004] The electrode bodies included in conventional energy storage elements may vary in thickness. In this case, it is preferable to arrange some kind of member to absorb the variation in the thickness of the electrode bodies, but this may result in the energy storage element becoming larger. For example, in the energy storage element disclosed in Patent Document 1, the thickness of the electrode bodies may vary. In particular, when multiple electrode bodies are arranged, the variation becomes greater. However, in the energy storage element disclosed in Patent Document 1, if some kind of member is arranged to absorb the variation in the thickness of the electrode bodies, the energy storage element becomes larger, and there is a risk that the energy storage element cannot be made smaller or have a higher capacity.

[0005] The present invention was made by the inventors of the present application by focusing on the above-mentioned problems, and has an object to provide an energy storage element that can be made smaller and has a higher capacity. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, an energy storage element according to one embodiment of the present invention comprises a plurality of electrode bodies arranged in a first direction, a current collector connected to ends of the plurality of electrode bodies in a second direction perpendicular to the first direction, an electrode terminal arranged in a third direction perpendicular to the first direction and the second direction of the plurality of electrode bodies and connected to the current collector, and a spacer arranged between two of the plurality of electrode bodies, wherein the spacer is arranged in a position in the third direction such that both ends do not protrude from at least one of the plurality of electrode bodies.

[0007] According to this, in the energy storage device, a current collector is connected to the second-direction ends of multiple electrode bodies arranged in a first direction, electrode terminals are arranged in a third direction of the multiple electrode bodies, and a spacer is arranged between two electrode bodies, and both ends of the spacer in the third direction do not protrude from at least one of the electrode bodies. In this way, when an energy storage device includes multiple electrode bodies arranged in a first direction, the thickness in the first direction may vary. However, by disposing the spacer between the two electrode bodies, this thickness variation can be absorbed. Here, because a current collector is connected to the second-direction (e.g., left-right) end of the electrode body, the current collector prevents the spacer from protruding from the electrode body in the second direction. Alternatively, even if the spacer protrudes from the electrode body in the second direction, as long as it does not protrude beyond the current collector, the energy storage device will not become large. On the other hand, in the third direction (e.g., the up-down direction) where the electrode terminals are arranged, the spacer is likely to protrude from the electrode body. If the spacer protrudes from all of the electrode bodies, the length (height) of the energy storage device in the third direction may increase, which may result in an increase in the size of the energy storage device. For this reason, the spacer is positioned so that both ends do not protrude beyond at least one of the electrode bodies in the third direction, which prevents the energy storage element from becoming larger in size in the third direction, thereby enabling the energy storage element to be made smaller or have a higher capacity.

[0008] Furthermore, a sheet member may be provided that connects the ends of the two electrode bodies in the third direction.

[0009] According to this, in an energy storage element, by connecting the third direction ends of two electrode bodies sandwiching a spacer with a sheet member, the sheet member prevents the spacer from protruding from the third direction ends of the two electrode bodies. This makes it easy to achieve a configuration in which the spacer does not protrude from at least one electrode body in the third direction, thereby enabling a compact energy storage element or a high capacity. Alternatively, by configuring the spacer not to protrude from the third direction ends of the two electrode bodies, contact between the spacer and the sheet member is suppressed, thereby suppressing damage to the sheet member by the spacer. By connecting the ends of the two electrode bodies with the sheet member, the spacer can be fixed in a sandwiched state between the two electrode bodies, making it easy to fix the spacer to multiple electrode bodies. This eliminates, for example, the need to bond the spacer to another member for fixation.

[0010] The sheet member may be arranged by being wrapped around the plurality of electrode bodies so as to surround the entire periphery of the plurality of electrode bodies.

[0011] According to this, by wrapping the sheet member so as to surround the entire periphery of the plurality of electrode bodies, the sheet member prevents the spacer from protruding from both sides of the plurality of electrode bodies in the third direction. This makes it easy to realize a configuration in which both ends of the spacer do not protrude from at least one electrode body in the third direction, thereby enabling the energy storage element to be made smaller or have a higher capacity. By wrapping the sheet member so as to surround the entire periphery of the plurality of electrode bodies, the spacer can be fixed in a sandwiched state between two electrode bodies, making it easy to fix the spacer to the plurality of electrode bodies.

[0012] Each of the two electrode bodies may have a pair of curved portions formed by winding an electrode plate and located at both ends in the third direction, and a flat portion connecting the pair of curved portions, and the spacer may be arranged between the flat portions of the two electrode bodies and positioned such that both ends do not protrude from the pair of curved portions of at least one of the two electrode bodies in the third direction.

[0013] In a flat, wound electrode body, thickness tends to vary, and when multiple flat, wound electrode bodies are arranged, the thickness variation may become large. Therefore, a spacer is arranged between the flat portions of two electrode bodies to absorb the thickness variation. Furthermore, by arranging the spacer in a position where both ends do not protrude beyond the pair of curved portions of at least one electrode body in the third direction, it is possible to prevent the energy storage element from becoming larger in the third direction, thereby enabling the energy storage element to be made smaller or have a higher capacity.

[0014] The spacer may be shorter than both of the two electrode assemblies in the third direction.

[0015] According to this, by making the spacer shorter in the third direction than both of the two electrode bodies that sandwich the spacer, it is possible to easily realize a configuration in which both ends of the spacer do not protrude from the two electrode bodies, which prevents the energy storage element from becoming larger in the third direction, thereby enabling the energy storage element to be made smaller or have a higher capacity.

[0016] A plurality of the spacers may be disposed between the two electrode bodies.

[0017] According to this, by disposing a plurality of spacers between the two electrode bodies, even if there is a large variation in the thickness of the plurality of electrode bodies, the variation in the thickness can be easily absorbed, thereby making it possible to achieve a smaller size or a higher capacity of the energy storage element while easily absorbing the variation in the thickness of the plurality of electrode bodies. [Effects of the Invention]

[0018] According to the energy storage device of the present invention, it is possible to achieve a reduction in size or a high capacity. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a perspective view showing the appearance of an energy storage element according to an embodiment; [Figure 2] 2 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. [Figure 3] FIG. 2 is an exploded perspective view showing the components of the energy storage device according to the embodiment. [Figure 4] FIG. 2 is a perspective view showing the configuration of an electrode body, a spacer, and a sheet member according to the embodiment. [Figure 5] 3 is a cross-sectional view showing the configuration of an electrode body, a spacer, and a sheet member according to the embodiment. FIG. [Figure 6] 10 is a cross-sectional view showing the configuration of an energy storage device including a plurality of spacers according to a modified example of the embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, with reference to the drawings, an energy storage element according to an embodiment of the present invention (including its modified examples) will be described. 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 only 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.

[0021] In the following description and drawings, the X-axis direction is defined as the arrangement direction of a pair of electrode terminals (positive and negative, hereinafter) of an energy storage element, the arrangement direction of a pair of current collectors, the width direction of the electrode assembly, the extension direction of the winding axis of the electrode assembly, the direction in which the ends of the electrode assembly connected to the current collectors are arranged, or the direction in which the short sides of the container face each other. The Y-axis direction is defined as the arrangement direction of multiple electrode assemblies, the stacking direction of the electrode plates of the electrode assembly, the thickness direction of the electrode assembly, the arrangement direction of the electrode assemblies and the spacers, the direction in which the long sides of the container face each other, or the thickness direction of the container. The Z-axis direction is defined as the height direction of the electrode assembly, the arrangement direction of the electrode terminals, the current collectors, and the electrode assembly, the arrangement direction of the container body and the lid of the container, or the up-down direction. The X-axis, Y-axis, and Z-axis directions intersect each other (orthogonal in this embodiment). Note that depending on the usage mode, the Z-axis may not be the up-down direction; however, for convenience of explanation, the Z-axis will be described below as the up-down direction.

[0022] In the following description, for example, 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 Y-axis direction may also be referred to as the first direction, the X-axis direction as the second direction, and the Z-axis direction as the third direction. Expressions indicating relative directions or orientations, such as "parallel" and "orthogonal," may also refer to cases where the directions or orientations are not strictly those of the same kind. For example, "two directions are orthogonal" does not only mean that the two directions are completely orthogonal, but also means that the two directions are substantially orthogonal, i.e., there is a difference of, for example, a few percent. Furthermore, in the following description, the term "insulation" refers to "electrical insulation."

[0023] (Embodiment) [1 General Description of Energy Storage Element 10] First, a general description of an energy storage device 10 according to the present embodiment will be given. Fig. 1 is a perspective view showing the appearance of an energy storage device 10 according to the present embodiment. Fig. 2 is a perspective view showing the internal configuration of a container 100 of an energy storage device 10 according to the present embodiment, with a container body 110 separated from the container 100. Fig. 3 is an exploded perspective view showing each component of an energy storage device 10 according to the present embodiment. Specifically, Fig. 3 shows each component of the energy storage device 10, with the container body 110 not shown.

[0024] The energy storage device 10 is a secondary battery (single cell) that can charge and discharge electricity, specifically a nonaqueous electrolyte secondary battery such as a lithium-ion secondary battery. The energy storage device 10 is used for power storage or power supply purposes. The energy storage device 10 is used, for example, as a battery for driving or starting the engine of a mobile object such as an automobile, motorcycle, personal watercraft, ship, snowmobile, agricultural machinery, construction machinery, or electric railway vehicle. Examples of the automobile include an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and a gasoline-powered automobile. Examples of the electric railway vehicle include a train, a monorail, a linear motor car, and a hybrid train equipped with both a diesel engine and an electric motor. The energy storage device 10 can also be used as a stationary battery for home or business use.

[0025] The energy storage element 10 is not limited to a non-aqueous electrolyte secondary battery, and may be a secondary battery other than a non-aqueous electrolyte secondary battery, or may be a capacitor. The energy storage element 10 may not be a secondary battery, but may be a primary battery that allows stored electricity to be used without the user having to charge it. The energy storage element 10 may be a battery that uses a solid electrolyte. The energy storage element 10 may also be a pouch-type energy storage element. In this embodiment, the energy storage element 10 is illustrated as having a flat rectangular parallelepiped (square) shape, but the shape of the energy storage element 10 is not limited to a rectangular parallelepiped shape, and may be a cylindrical shape, an elongated cylindrical shape, a polygonal prism shape other than a rectangular parallelepiped, or the like.

[0026] As shown in FIG. 1, the energy storage device 10 includes a container 100, a pair of electrode terminals 200 (positive and negative), and a pair of upper gaskets 300 (positive and negative). As shown in FIGS. 2 and 3, the container 100 contains a pair of lower gaskets 400 (positive and negative), a pair of current collectors 500 (positive and negative), a plurality of electrode assemblies (two electrode assemblies 600 and 700), a spacer 800, and a sheet member 900. An electrolyte (non-aqueous electrolyte) is enclosed within the container 100, but is not shown. The electrolyte may be of any type, provided it does not impair the performance of the energy storage device 10, and various types may be selected. In addition to the above components, spacers or the like may be disposed on the sides or below the electrode assemblies 600 and 700.

[0027] The container 100 is a rectangular parallelepiped (square or box-shaped) case having a container body 110 with an opening formed therein 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 constitutes the main body of the container 100. The container body 110 has a pair of flat, rectangular long side walls 111 on both side surfaces (long side surfaces) in the Y-axis direction, a pair of flat, rectangular short side walls 112 on both side surfaces (short side surfaces) in the X-axis direction, and a flat, rectangular bottom wall 113 on the negative Z-axis side. The lid 120 is a rectangular plate-like member that constitutes the lid of the container 100 and is disposed so as to extend in the X-axis direction in the positive Z-axis direction of the container body 110. The lid 120 is provided with a gas exhaust valve 121 for releasing the pressure inside the container 100 if the pressure rises excessively, and a liquid injection section (not shown) for injecting the electrolyte into the container 100.

[0028] With this configuration, the container 100 has a structure in which the current collector 500, the electrode assemblies 600 and 700, the spacer 800, etc. are housed inside the container body 110, and then the container body 110 and the lid 120 are joined by welding or the like, thereby sealing the interior. The material of the container 100 (container body 110 and lid 120) is not particularly limited, and can be a weldable metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet, but resin can also be used.

[0029] The electrode terminals 200 are disposed in the positive Z-axis direction (above) of the current collector 500 and the electrode bodies 600 and 700, and are terminal members (positive electrode terminal and negative electrode terminal) electrically connected to the electrode bodies 600 and 700 via the current collector 500. The electrode terminals 200 are metal members for conducting electricity stored in the electrode bodies 600 and 700 to the external space of the energy storage element 10 and for introducing electricity into the internal space of the energy storage element 10 in order to store electricity in the electrode bodies 600 and 700. The electrode terminals 200 are formed of a conductive member such as a metal, such as aluminum, an aluminum alloy, copper, or a copper alloy. The electrode terminals 200 are connected (joined) to the current collector 500 by crimping or the like, and are attached to the lid body 120.

[0030] Specifically, the electrode terminal 200 has a shaft portion 201 (rivet portion) extending downward (in the negative Z-axis direction). The shaft portion 201 is inserted into the through-hole 301 of the upper gasket 300, the through-hole 122 of the lid 120, the through-hole 401 of the lower gasket 400, and the through-hole 501 of the current collector 500, and is crimped. As a result, the electrode terminal 200, together with the upper gasket 300, the lower gasket 400, and the current collector 500, is fixed to the lid 120. In this way, the electrode terminal 200 is arranged in the Z-axis direction (a third direction perpendicular to the first and second directions) of the multiple electrode bodies (two electrode bodies 600 and 700), and is connected to the current collector 500. The method for connecting (joining) the electrode terminal 200 and the current collector 500 is not limited to crimping, and may be ultrasonic welding, laser welding, resistance welding, or other mechanical joining other than crimping, such as screw fastening.

[0031] Each of the multiple electrode bodies (two electrode bodies 600 and 700) includes a positive electrode plate, a negative electrode plate, and a separator, and is an electricity storage element (power generation element) capable of storing electricity. The multiple electrode bodies (two electrode bodies 600 and 700) are arranged side by side in the Y-axis direction (first direction). Each of the electrode bodies 600 and 700 is a so-called vertically wound flat wound electrode body that has an oval shape when viewed in the X-axis direction, and is formed by winding layers of positive and negative electrode plates with a separator sandwiched between them. The electrode bodies 600 and 700 have a similar configuration.

[0032] 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 substrate layer, which is a long strip of metal foil made of 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 substrate layer, which is a long strip of metal foil made of copper or a copper alloy. For the positive electrode substrate layer and the negative electrode substrate layer, any known material can be used as long as it is stable against oxidation-reduction reactions during charging and discharging, such as nickel, iron, stainless steel, titanium, baked carbon, conductive polymers, conductive glass, and Al-Cd alloys. 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 can be any known material as long as it is capable of absorbing and releasing lithium ions. For the separator material, any known material can be used as long as it does not impair the performance of the energy storage device 10.

[0033] Positive electrode active materials include polyanion compounds such as LiMPO4, LiMSiO4, and LiMBO3 (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), lithium titanate, LiMn2O4, and LiMn 1.5 Ni 0.5Examples of the anode active material include spinel-type lithium manganese oxides such as LiTiO4, and lithium transition metal oxides such as LiMO2 (wherein M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.). Examples of the anode active material include lithium metal, lithium alloys (lithium-metal-containing alloys such as lithium-silicon, lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and Wood's alloy), alloys capable of absorbing and releasing lithium, carbon materials (e.g., graphite, non-graphitizable carbon, easily graphitizable carbon, low-temperature fired carbon, amorphous carbon, etc.), silicon oxides, metal oxides, and lithium metal oxides (Li4Ti5O 12 Examples of the separator include polyphosphate compounds, and compounds of transition metals and elements of Groups 14 to 16, such as Co3O4 and Fe2P, which are commonly called conversion negative electrodes. The separator is a microporous sheet made of resin, and examples that can be used include woven fabric or nonwoven fabric that is insoluble in organic solvents, and synthetic resin microporous membranes made of polyolefin resins such as polyethylene.

[0034] Specifically, the electrode assembly 600 has a positive electrode plate and a negative electrode plate wound with a separator interposed therebetween, offset from each other in the direction of the winding axis. The winding axis is a virtual axis that serves as the central axis when winding the positive electrode plate, negative electrode plate, etc., and in this embodiment, is a straight line that passes through the center of the electrode assembly 600 and is parallel to the X-axis direction. The positive electrode plate and negative electrode plate each have a portion (active material layer non-formed portion) at the end in the offset direction where no active material is formed (coated) and the base material layer is exposed.

[0035] As a result, the electrode body 600 has a positive electrode-side laminated portion 601 at one end in the winding axis direction, where the active material layer-free portions of the positive electrode plates are stacked and bundled, and a negative electrode-side laminated portion 601 at the other end in the winding axis direction, where the active material layer-free portions of the negative electrode plates are stacked and bundled. The laminated portion 601 is a portion where the electrode plates (positive electrode plates or negative electrode plates) are stacked in the stacking direction (Y-axis direction). In other words, the electrode body 600 has an electrode body main body portion 610 (see FIG. 4 ) that constitutes the main body of the electrode body 600, and a pair of laminated portions 601 (positive electrode side and negative electrode side) that protrude on both sides in the X-axis direction from the electrode body main body portion 610. The electrode body main body portion 610 is an oval-shaped portion (active material layer-forming portion) formed by winding the separator and the portions of the positive electrode plates and negative electrode plates where the active material layers are formed (coated). Similarly, the electrode body 700 has an electrode body main body portion 710 (see FIG. 4) that constitutes the main body of the electrode body 700, and a pair of laminated portions 701 (positive electrode side and negative electrode side) that protrude on both sides in the X-axis direction from the electrode body main body portion 710. The configurations of the electrode bodies 600 and 700 will be described in detail later.

[0036] The spacer 800 is a flat, rectangular member disposed between the two electrode bodies 600 and 700 (see FIG. 4). The spacer 800 is formed of an insulating resin, such as polypropylene (PP), polyethylene (PE), polystyrene (PS), polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyether ether ketone (PEEK), tetrafluoroethylene-perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyether sulfone (PES), ABS resin, or a composite material thereof. The material of the spacer 800 is not particularly limited, and it may be formed of a heat insulating material, such as a damping material, or an elastic material, such as rubber. The spacer 800 may be made of a conductive material such as a metal material as long as the insulation between the electrode assemblies 600 and 700 is ensured or there is no need to insulate the electrode assemblies 600 and 700. The configuration of the spacer 800 will be described in detail later.

[0037] The sheet member 900 is a sheet-like member (binding sheet) that connects the ends of the two electrode bodies 600 and 700 in the Z-axis direction (third direction). In this embodiment, the sheet member 900 connects both ends of the electrode bodies 600 and 700 in the Z-axis direction. Specifically, the sheet member 900 is an annular member that surrounds both sides of the electrode bodies 600 and 700 in the Y-axis direction and the Z-axis direction. The sheet member 900 can be formed of an insulating member, such as any insulating resin material that can be used for the spacer 800. Note that if the insulation of the electrode bodies 600 and 700 is ensured by other members or if insulation of the electrode bodies 600 and 700 is not necessary, the sheet member 900 may be formed of a conductive member, such as a metal material. A detailed description of the configuration of the sheet member 900 will be given later.

[0038] The current collectors 500 are current collecting members (positive electrode current collector and negative electrode current collector) disposed on both sides of the electrode assemblies 600 and 700 in the X-axis direction, and electrically connect the electrode assemblies 600 and 700 to the electrode terminal 200. Specifically, the positive electrode side current collector 500 is connected (joined) to the positive electrode side laminated portions 601 and 701 of the electrode assemblies 600 and 700 by welding or the like, and is also joined to the positive electrode side electrode terminal 200 by crimping or the like, as described above. The negative electrode side current collector 500 is connected (joined) to the negative electrode side laminated portions 601 and 701 of the electrode assemblies 600 and 700 by welding or the like, and is also joined to the negative electrode side electrode terminal 200 by crimping or the like, as described above. In this way, the current collectors 500 are connected to the ends of the multiple electrode assemblies (two electrode assemblies 600 and 700) in the X-axis direction (a second direction perpendicular to the first direction).

[0039] The current collector 500 is a plate-like member that is bent and disposed along the side wall and the lid 120 from the side wall of the container body 110 to the lid 120. The current collector 500 is fixedly connected (joined) to the lid 120. With this configuration, the electrode assemblies 600 and 700 are held (supported) in a suspended state from the lid 120 by the current collector 500, thereby suppressing shaking due to vibration, impact, and the like. The material of the current collector 500 is not particularly limited, but for example, the positive electrode side current collector 500 is formed of a conductive material such as a metal, such as aluminum or an aluminum alloy, and the negative electrode side current collector 500 is formed of a conductive material such as a metal, such as copper or a copper alloy. Note that the method for connecting (joining) the current collector 500 and the laminated portions 601 and 701 may be any welding method, such as ultrasonic welding, laser welding, or resistance welding, or may be mechanical joining such as crimping or screw fastening.

[0040] The positive and negative electrode current collectors 500 have shapes symmetrical with respect to the YZ plane. As shown in Fig. 3, each current collector 500 has a terminal connection portion 510 and four electrode connection portions 520 extending from the terminal connection portion 510 in the negative Z-axis direction. The terminal connection portion 510 is a base portion of the current collector 500 that is connected (joined) to the electrode terminal 200. The terminal connection portion 510 is a flat portion parallel to the XY plane in which the above-mentioned through-hole 501 is formed, and is disposed on the electrode terminal 200 side (upper side, positive Z-axis direction) of the current collector 500. The electrode connection portions 520 are legs of the current collector 500 that are connected (joined) to the electrode bodies 600 and 700. The electrode connection portion 520 is an elongated, flat portion that extends in the negative Z-axis direction from the end portion in the X-axis direction of the terminal connection portion 510, and is disposed on the electrode bodies 600 and 700 side (lower side, negative Z-axis direction) of the current collector 500. In this embodiment, of the four electrode connection portions 520, two electrode connection portions 520 are disposed at positions that sandwich the laminated portion 601 of the electrode body 600 in the Y-axis direction and are joined to the laminated portion 601, and two electrode connection portions 520 are disposed at positions that sandwich the laminated portion 701 of the electrode body 700 in the Y-axis direction and are joined to the laminated portion 701.

[0041] The upper gasket 300 is a plate-shaped member (positive electrode upper gasket and negative electrode upper gasket) that is disposed between the lid 120 of the container 100 and the electrode terminal 200, and that insulates and seals between the lid 120 and the electrode terminal 200. The lower gasket 400 is a plate-shaped member (positive electrode lower gasket and negative electrode lower gasket) that is disposed between the lid 120 and the current collector 500, and that insulates between the lid 120 and the current collector 500. The upper gasket 300 and the lower gasket 400 are formed, for example, from any insulating resin material that can be used for the spacer 800 described above.

[0042] [2. Description of the Configurations of the Electrode Bodies 600 and 700, the Spacer 800, and the Sheet Member 900] Next, the configurations of the electrode assemblies 600 and 700, the spacer 800, and the sheet member 900 will be described in detail. FIG. 4 is a perspective view showing the configurations of the electrode assemblies 600 and 700, the spacer 800, and the sheet member 900 according to the present embodiment. Specifically, FIG. 4 is an exploded perspective view showing the respective components of the electrode assemblies 600 and 700, the spacer 800, and the sheet member 900 shown in FIG. 3. FIG. 5 is a cross-sectional view showing the configurations of the electrode assemblies 600 and 700, the spacer 800, and the sheet member 900 according to the present embodiment. Specifically, FIG. 5 is a cross-sectional view showing the configuration when the central portion of the energy storage element 10 shown in FIG. 1 is cut along a plane parallel to the YZ plane.

[0043] As described above, the electrode bodies 600 and 700 are each flat, oval-shaped wound electrode bodies formed by winding a separator sandwiched between a positive electrode plate and a negative electrode plate. That is, the electrode body main body portions 610 and 710 are elongated columnar or cylindrical portions formed by winding the separator and the portions of the positive and negative electrode plates on which the active material layers are formed. As a result, as shown in FIGS. 4 and 5 , the electrode body main body portion 610 has a pair of electrode body flat portions 611 and 612 located on both sides in the Y axis direction (first direction) and a pair of electrode body curved portions 613 and 614 located at both ends in the Z axis direction (third direction). The electrode body main body portion 710 has a pair of electrode body flat portions 711 and 712 located on both sides in the Y axis direction (first direction) and a pair of electrode body curved portions 713 and 714 located at both ends in the Z axis direction (third direction).

[0044] The electrode body flat portion 611 is a flat, rectangular portion extending parallel to the XZ plane oriented in the negative Y-axis direction, connecting the pair of electrode body curved portions 613 and 614, and is disposed opposite the long side wall portion 111 of the container body 110 in the negative Y-axis direction. The electrode body flat portion 612 is a flat, rectangular portion extending parallel to the XZ plane oriented in the positive Y-axis direction, connecting the pair of electrode body curved portions 613 and 614, and is disposed opposite the spacer 800. The electrode body curved portion 613 is a curved portion that curves in a semicircular arc shape so as to protrude in the positive Z-axis direction when viewed from the X-axis direction, and extends in the X-axis direction, and is disposed opposite the lid 120. The electrode body curved portion 614 is a curved portion that curves in a semicircular arc shape so as to protrude in the negative Z-axis direction when viewed from the X-axis direction, and extends in the X-axis direction, and is disposed opposite the bottom wall portion 113 of the container body 110.

[0045] The electrode body flat portion 711 is a flat, rectangular portion extending parallel to the XZ plane oriented in the negative Y-axis direction, connecting the pair of electrode body curved portions 713 and 714, and is disposed opposite the spacer 800. The electrode body flat portion 712 is a flat, rectangular portion extending parallel to the XZ plane oriented in the positive Y-axis direction, connecting the pair of electrode body curved portions 713 and 714, and is disposed opposite the long side wall portion 111 of the container body 110 in the positive Y-axis direction. The electrode body curved portion 713 is a curved portion that curves in a semicircular arc shape so as to protrude in the positive Z-axis direction when viewed from the X-axis direction, and extends in the X-axis direction, and is disposed opposite the lid 120. The electrode body curved portion 714 is a curved portion that curves in a semicircular arc shape so as to protrude in the negative Z-axis direction when viewed from the X-axis direction, and extends in the X-axis direction, and is disposed opposite the bottom wall portion 113 of the container body 110.

[0046] As described above, the sheet member 900 is a member that connects the ends (curved portions) of the two electrode bodies 600 and 700 in the Z-axis direction (third direction). That is, the sheet member 900 connects the electrode body curved portions 613 and 713 of the electrode body main bodies 610 and 710, and also connects the electrode body curved portions 614 and 714. Specifically, the sheet member 900 has a pair of opposing first sheet portions 910 and 920 on both side surfaces in the Y-axis direction, and a pair of opposing second sheet portions 930 and 940 on both upper and lower surfaces in the Z-axis direction. Both ends of the pair of first sheet portions 910 and 920 in the Z-axis direction and both ends of the pair of second sheet portions 930 and 940 in the Y-axis direction are connected to form the rectangular annular sheet member 900. As a result, the sheet member 900 is arranged by being wrapped around the plurality of electrode bodies (the two electrode bodies 600 and 700) so as to surround the entire periphery of the plurality of electrode bodies (the two electrode bodies 600 and 700).

[0047] The sheet member 900 may have a rectangular annular shape before being wound around the electrode bodies 600 and 700 (before being constrained), or may have a curved shape such as a circular annular shape before being wound around the electrode bodies 600 and 700 (before being constrained). In other words, the sheet member 900 may have a curved shape before being wound around the electrode bodies 600 and 700 (before being constrained), and may be in close contact with the electrode bodies 600 and 700 after being wound around the electrode bodies 600 and 700 (after being constrained), thereby forming a pair of planar first sheet portions 910 and 920 and a pair of planar second sheet portions 930 and 940. The sheet member 900 may be a single sheet (or multiple sheets) before being wound around the electrode bodies 600 and 700, and after being wound around the electrode bodies 600 and 700, the ends of the sheets may be connected (joined) to constrain the electrode bodies 600 and 700.

[0048] The first sheet portions 910 and 920 are sheet-like, rectangular portions parallel to the XZ plane, and are arranged at positions sandwiching the electrode assemblies 600 and 700 and the spacer 800 in the Y-axis direction. The first sheet portions 910 and 920 are adjacent to the second sheet portions 930 and 940, and have outer surface areas larger than those of the second sheet portions 930 and 940. The first sheet portion 910 is arranged in the negative Y-axis direction of the electrode body flat portion 611 of the electrode body main body portion 610, and is arranged between the electrode body flat portion 611 and the long side wall portion 111 of the container body 110 in the negative Y-axis direction, in contact with the electrode body flat portion 611 and the long side wall portion 111. The first sheet portion 920 is arranged in the positive Y-axis direction of the electrode body flat portion 712 of the electrode body main body portion 710, and is arranged in contact with the electrode body flat portion 712 and the long side wall portion 111 in the positive Y-axis direction of the container body 110 between the electrode body flat portion 712 and the long side wall portion 111.

[0049] The second sheet portions 930 and 940 are sheet-like, rectangular portions parallel to the XY plane, and are arranged across the two electrode bodies 600 and 700 at positions sandwiching the electrode bodies 600 and 700 and the spacer 800 in the Z-axis direction. The second sheet portions 930 and 940 are adjacent to the first sheet portions 910 and 920, and have smaller outer surface areas than the first sheet portions 910 and 920. Note that the first sheet portions 910 and 920 may have smaller outer surface areas than the second sheet portions 930 and 940. The second sheet portion 930 is arranged in the positive Z-axis direction of the electrode body curved portions 613 and 713 of the electrode body main portions 610 and 710, and is arranged between the electrode body curved portions 613 and 713 and the cover body 120, abutting against the electrode body curved portions 613 and 713. The second sheet portion 940 is arranged in the negative Z-axis direction of the electrode body curved portions 614 and 714 of the electrode body main body portions 610 and 710, and is arranged between the electrode body curved portions 614 and 714 and the bottom wall portion 113 of the container body 110, in contact with the electrode body curved portions 614 and 714 and the bottom wall portion 113.

[0050] In this embodiment, the sheet member 900 (first sheet portions 910 and 920 and second sheet portions 930 and 940) is formed of a heat-shrinkable sheet-like member, adhesive tape, or the like. The sheet member 900 is, for example, a ring-shaped shrink sheet made of a heat-shrinkable resin or the like, and is configured to be wrapped around the electrode bodies 600 and 700 and then shrink by heat to constrain the electrode bodies 600 and 700. The sheet member 900 may be an adhesive tape (insulating tape) such as glass cloth tape, and may be configured to constrain the electrode bodies 600 and 700 by connecting both ends of the electrode bodies 600 and 700 in the Z-axis direction. In this case, the sheet member 900 may have two sheet members: one sheet member connecting the ends of the electrode bodies 600 and 700 in the positive Z-axis direction, and the other sheet member connecting the ends of the electrode bodies 600 and 700 in the negative Z-axis direction. In other words, the first sheet portions 910 and 920 may be divided in the Z-axis direction.

[0051] 5, the spacer 800 is disposed between the flat portions of the two electrode assemblies 600 and 700. Specifically, the spacer 800 is disposed between the electrode assembly flat portions 612 and 711 of the electrode assembly main body portions 610 and 710 of the electrode assemblies 600 and 700, and is disposed in contact with the electrode assembly flat portions 612 and 711. The spacer 800 is disposed in a position in the Z-axis direction (third direction) such that both ends thereof do not protrude from at least one of the electrode assemblies (electrode assemblies 600 and 700). In other words, the spacer 800 is disposed in a position in the Z-axis direction (third direction) such that both ends thereof do not protrude from a pair of curved portions (electrode assembly curved portions 613 and 614, or electrode assembly curved portions 713 and 714) of at least one of the two electrode assemblies 600 and 700.

[0052] In this embodiment, the spacer 800 is shorter than both of the two electrode assemblies 600 and 700 in the Z-axis direction (third direction). As a result, the spacer 800 is disposed in a position in which both ends thereof do not protrude from either of the two electrode assemblies 600 and 700 in the Z-axis direction. That is, the spacer 800 is disposed in a position in which it does not protrude from the electrode assembly curved portions 613 and 614 and the electrode assembly curved portions 713 and 714, which are pairs of curved portions of both of the two electrode assemblies 600 and 700, in the Z-axis direction. Specifically, the spacer 800 is disposed in a position in which it protrudes from the electrode assembly flat portions 612 and 711 of the electrode assembly main body portions 610 and 710 of the electrode assemblies 600 and 700 in the Z-axis direction, but does not protrude from the electrode assembly curved portions 613 and 614 and the electrode assembly curved portions 713 and 714. In the present embodiment, the electrode body curved portions 613 and 614 and the electrode body curved portions 713 and 714 of the electrode bodies 600 and 700 are arranged so as to protrude from the spacer 800. As a result, the spacer 800 does not abut against the second sheet portions 930 and 940 of the sheet member 900.

[0053] [3 Explanation of effects] As described above, in the energy storage device 10 according to the embodiment of the present invention, the current collector 500 is connected to the ends in the second direction (X-axis direction) of the two electrode bodies 600 and 700 aligned in the first direction (Y-axis direction), and the electrode terminal 200 is disposed in the third direction (Z-axis direction) of the electrode bodies 600 and 700. The spacer 800 is disposed between the two electrode bodies 600 and 700, and both ends of the spacer 800 in the third direction do not protrude from at least one of the electrode bodies (in this embodiment, both of the electrode bodies 600 and 700). In this way, when the energy storage device 10 includes the two electrode bodies 600 and 700 aligned in the first direction, there may be variations in thickness in the first direction. However, by disposing the spacer 800 between the two electrode bodies 600 and 700, the variations in thickness can be absorbed. Here, because the current collector 500 is connected to the ends of the electrode assemblies 600 and 700 in the second direction (left-right direction), the current collector 500 prevents the spacer 800 from protruding from the electrode assemblies 600 and 700 in the second direction. Even if the spacer 800 protrudes from the electrode assemblies 600 and 700 in the second direction, the energy storage device 10 will not become larger if it does not protrude further than the current collector 500. In contrast, the spacer 800 is likely to protrude from the electrode assemblies 600 and 700 in the third direction (up-down direction). If the spacer 800 protrudes from the electrode assemblies 600 and 700, the length (height) of the energy storage device 10 in the third direction may increase, potentially resulting in an increase in the size of the energy storage device 10. Therefore, the spacer 800 is positioned in a position in the third direction such that both ends do not protrude from at least one electrode assembly (in this embodiment, both electrode assemblies 600 and 700). This prevents energy storage device 10 from becoming larger in size in the third direction, allowing energy storage device 10 to be made smaller or have a higher capacity.

[0054] By connecting the third direction ends of the two electrode bodies 600 and 700 that sandwich the spacer 800 with the sheet member 900, the sheet member 900 prevents the spacer 800 from protruding from the third direction ends of the two electrode bodies 600 and 700. This makes it easy to realize a configuration in which the spacer 800 does not protrude from at least one electrode body (in this embodiment, both electrode bodies 600 and 700) in the third direction, thereby enabling the energy storage device 10 to be reduced in size or have a higher capacity. Alternatively, by configuring the spacer 800 so that it does not protrude from the third direction ends of the two electrode bodies 600 and 700, contact between the spacer 800 and the sheet member 900 is suppressed, and therefore damage to the sheet member 900 by the spacer 800 can be suppressed. The sheet member 900 connects the ends of the two electrode bodies 600 and 700, and thus the spacer 800 can be fixed in a sandwiched state between the two electrode bodies 600 and 700, and therefore the spacer 800 can be easily fixed to the two electrode bodies 600 and 700. This eliminates the need to, for example, bond and fix the spacer 800 to another member.

[0055] By wrapping the sheet member 900 so as to surround the entire periphery of the two electrode bodies 600 and 700, the sheet member 900 prevents the spacer 800 from protruding from both sides of the two electrode bodies 600 and 700 in the third direction. This makes it easy to realize a configuration in which both ends of the spacer 800 do not protrude from at least one of the electrode bodies (in this embodiment, both of the electrode bodies 600 and 700) in the third direction, thereby enabling the energy storage device 10 to be reduced in size or have a higher capacity. By wrapping the sheet member 900 so as to surround the entire periphery of the two electrode bodies 600 and 700, the spacer 800 can be fixed in a sandwiched state between the two electrode bodies 600 and 700, and therefore the spacer 800 can be easily fixed to the two electrode bodies 600 and 700.

[0056] In a flat, wound electrode body, thickness tends to vary, and when two flat, wound electrode bodies 600 and 700 are arranged, the thickness variation may become large. For this reason, a spacer 800 is arranged between the electrode body flat portions 612 and 711 of the two electrode bodies 600 and 700 to absorb the thickness variation. Furthermore, the spacer 800 is arranged in a position such that both ends thereof do not protrude from a pair of curved portions of at least one electrode body in the third direction (in this embodiment, the electrode body curved portions 613 and 614, and the electrode body curved portions 713 and 714). This prevents the energy storage element 10 from becoming larger in the third direction, thereby enabling the energy storage element 10 to be made smaller or have a higher capacity.

[0057] By making the spacer 800 shorter in the third direction than both of the two electrode bodies 600 and 700 that sandwich the spacer 800, it is possible to easily achieve a configuration in which both ends of the spacer 800 do not protrude from the two electrode bodies 600 and 700. This makes it possible to prevent the energy storage device 10 from becoming larger in size in the third direction, thereby enabling the energy storage device 10 to be made smaller or have a higher capacity. By making the spacer 800 shorter in the third direction than both of the two electrode bodies 600 and 700, it is possible to prevent the spacer 800 from contacting the sheet member 900 that connects the two electrode bodies 600 and 700 and damaging the sheet member 900.

[0058] [4 Explanation of Variations] Although the energy storage device 10 according to the embodiment of the present invention has been described above, the present invention is not limited to this embodiment. The embodiment disclosed herein is illustrative in all respects, and the scope of the present invention includes all modifications within the meaning and scope of the claims.

[0059] For example, in the above embodiment, one spacer 800 is disposed between the two electrode assemblies 600 and 700. However, multiple spacers 800 may be disposed between the two electrode assemblies 600 and 700. FIG. 6 is a cross-sectional view showing the configuration of an energy storage device 11 including multiple spacers 800 according to a modification of the present embodiment. Specifically, FIG. 6 corresponds to FIG. 5. As shown in FIG. 6, the energy storage device 11 includes two spacers 800 disposed between the electrode assemblies 600 and 700, stacked in the Y-axis direction. Specifically, the two spacers 800 are disposed between the electrode assembly flat portions 612 and 711 of the electrode assemblies 600 and 700. Note that the number of spacers 800 is not particularly limited, and three or more spacers 800 may be disposed between the electrode assemblies 600 and 700. The other configuration of this modification is the same as that of the above embodiment. As described above, the energy storage device 11 according to this modification can achieve the same effects as those of the above embodiment. In particular, in this modification, by disposing a plurality of spacers 800 between the two electrode bodies 600 and 700, even if there is a large variation in the thickness of the electrode bodies 600 and 700, the variation in the thickness can be easily absorbed. This makes it possible to reduce the size or increase the capacity of the energy storage element 11 while easily absorbing the variation in the thickness of the electrode bodies 600 and 700.

[0060] In the above embodiment, the spacer 800 is not in contact with the second sheet portions 930 and 940 of the sheet member 900. However, the spacer 800 may be in contact with at least one of the second sheet portions 930 and 940. In other words, the spacer 800 may have the same length as the electrode bodies 600 and 700 in the Z-axis direction.

[0061] In the above embodiment, the electrode bodies 600 and 700 have an oval shape when viewed in the Z-axis direction, but the shape is not particularly limited and may be circular, elliptical, polygonal, or the like. The shape of the electrode bodies 600 and 700 is not limited to a wound type, and may be a stack type in which flat electrode plates are stacked, or a shape in which electrode plates are folded like an accordion. The electrode bodies 600 and 700 may have tabs.

[0062] In the above embodiment, two electrode bodies, 600 and 700, are arranged side by side in the Y-axis direction, but three or more electrode bodies may be arranged side by side in the Y-axis direction. In this case, it is sufficient that at least one spacer 800 is arranged between at least two electrode bodies. In other words, spacers 800 may be arranged between all of the electrode bodies, or spacers 800 may be arranged between any two of the electrode bodies.

[0063] In the above embodiment, the electrode assemblies 600 and 700 have the same length in the Z-axis direction, but the lengths in the Z-axis direction may be different. In this case, the spacer 800 only needs to be positioned so that both ends do not protrude from at least one of the two electrode assemblies in the Z-axis direction. In other words, both ends of the spacer 800 do not need to protrude from the longer electrode assembly in the Z-axis direction, and may protrude from the shorter electrode assembly. When three or more electrode assemblies with different lengths in the Z-axis direction are disposed, it is only necessary that both ends of the spacer 800 do not protrude from the longest electrode assembly in the Z-axis direction.

[0064] In the above embodiment, the sheet member 900 connects the ends of the electrode bodies 600 and 700 in both directions in the Z axis direction, but it may also connect the ends of the electrode bodies 600 and 700 in only one direction in the Z axis direction. Alternatively, the energy storage element may not include the sheet member 900.

[0065] Any combination of the above-described embodiments and modifications is also included within the scope of the present invention. [Industrial Applicability]

[0066] The present invention can be applied to an electric storage element such as a lithium ion secondary battery. [Explanation of symbols]

[0067] 10, 11 Energy storage element 100 containers 110 Container body 111 Long side wall 112 Short side wall 113 Bottom wall 120 Lid 121 Gas exhaust valve 122, 301, 401, 501 through holes 200 electrode terminal 201 Shaft 300 Upper Gasket 400 Lower Gasket 500 current collector 510 Terminal connection part 520 Electrode connection part 600, 700 electrode body 601, 701 stacked section 610, 710 Electrode body part 611, 612, 711, 712 Flat part of electrode body 613, 614, 713, 714 Electrode body curved part 800 spacer 900 Sheet material 910, 920 First seat section 930, 940 Second seat section

Claims

1. A plurality of electrode bodies arranged in a first direction; a current collector connected to an end portion of each of the plurality of electrode bodies in a second direction perpendicular to the first direction; electrode terminals arranged in a third direction perpendicular to the first direction and the second direction of the plurality of electrode bodies and connected to the current collectors; a spacer disposed between two of the plurality of electrode bodies in contact with the two electrode bodies and electrically insulated from the two electrode bodies; Each of the plurality of electrode assemblies includes an electrode plate and a separator, the spacer is disposed at a position such that both ends thereof do not protrude from at least one of the plurality of electrode bodies in the third direction; A portion of the spacer is disposed at a position facing the center in the third direction of at least one of the plurality of electrode bodies. Energy storage element.

2. a container having a long side and a short side; a plurality of electrode assemblies accommodated in the container and arranged in a first direction; a current collector connected to an end portion of each of the plurality of electrode bodies in a second direction perpendicular to the first direction; electrode terminals arranged in a third direction perpendicular to the first direction and the second direction of the plurality of electrode bodies and connected to the current collectors; a spacer that is not disposed between the long side surface of the container and the plurality of electrode bodies, but is disposed between two of the plurality of electrode bodies in a state of contact with the two electrode bodies; Each of the plurality of electrode assemblies includes an electrode plate and a separator, the spacer is disposed at a position such that both ends thereof do not protrude from at least one of the plurality of electrode bodies in the third direction; A portion of the spacer is disposed at a position facing the center in the third direction of at least one of the plurality of electrode bodies. Energy storage element.

3. A plurality of electrode bodies arranged in a first direction; a current collector connected to an end portion of each of the plurality of electrode bodies in a second direction perpendicular to the first direction; electrode terminals arranged in a third direction perpendicular to the first direction and the second direction of the plurality of electrode bodies and connected to the current collectors; a spacer disposed between two of the plurality of electrode bodies and electrically insulated from the two electrode bodies; a sheet member connecting the ends of the two electrode bodies in the third direction, Each of the plurality of electrode assemblies includes an electrode plate and a separator, the spacer is disposed at a position such that both ends thereof do not protrude from at least one of the plurality of electrode bodies in the third direction; A portion of the spacer is disposed at a position facing the center in the third direction of at least one of the plurality of electrode bodies. Energy storage element.

4. a container having a long side and a short side; a plurality of electrode assemblies accommodated in the container and arranged in a first direction; a current collector connected to an end portion of each of the plurality of electrode bodies in a second direction perpendicular to the first direction; electrode terminals arranged in a third direction perpendicular to the first direction and the second direction of the plurality of electrode bodies and connected to the current collectors; a spacer that is not disposed between the long side surface of the container and the plurality of electrode bodies but is disposed between two of the plurality of electrode bodies; a sheet member connecting the ends of the two electrode bodies in the third direction, Each of the plurality of electrode assemblies includes an electrode plate and a separator, the spacer is disposed at a position such that both ends thereof do not protrude from at least one of the plurality of electrode bodies in the third direction; A portion of the spacer is disposed at a position facing the center in the third direction of at least one of the plurality of electrode bodies. Energy storage element.

5. The sheet member is wound around the electrode bodies so as to surround the entire periphery of the electrode bodies. The energy storage element according to claim 3 or 4.

6. Each of the two electrode bodies has a pair of curved portions formed by winding the electrode plate and positioned at both ends in the third direction, and a flat portion connecting the pair of curved portions, The spacer is disposed between the flat portions of the two electrode bodies, and is disposed at a position such that both ends thereof do not protrude from a pair of curved portions of at least one of the two electrode bodies in the third direction. The energy storage element according to any one of claims 1 to 5.

7. The spacer is shorter than both of the two electrode assemblies in the third direction. The energy storage element according to any one of claims 1 to 6.

8. A plurality of the spacers are disposed between the two electrode bodies. The energy storage element according to any one of claims 1 to 7.

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