Power storage device

Abstract

A powder storage device comprising: a stacked body that is formed by stacking a plurality of electrodes containing a current collector and an active material layer provided on the current collector; a sealing part that surrounds the stacked body and seals between each of the adjacent electrodes in the stacking direction of the stacked body; a plurality of detecting lines that are connected to the electrodes and are pulled out of the sealing part to the exterior; and a cooling member that is in contact with the stacked body and has a cooling flow path for allowing a cooling fluid to flow therethrough from an inlet to an outlet in a direction orthogonal to the stacking direction, wherein the sealing part includes a pulled out portion having each of the plurality of detecting lines pulled out therefrom, and the pulled out portion is positioned closer to the inlet than to the outlet of the cooling flow path when viewed from the stacking direction.

Description

[Technical field]

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

[0002] Patent Document 1 describes a bipolar battery. This bipolar battery has a configuration in which a bipolar electrode, in which a positive electrode layer is formed on one surface of a current collector and a negative electrode layer is formed on the other surface, is stacked with an electrolyte layer formed by a separator holding an electrolyte, and multiple sheets are arranged in series. A single cell layer is formed by a stacked structure in which an electrolyte layer is sandwiched between the positive electrode layer and the negative electrode layer, and a battery element is formed by stacking multiple single cell layers. The entire periphery of the battery element is covered with a resin group that maintains the airtightness of the battery element. Each current collector is provided with a voltage detection tab for detecting the terminal voltage of each single cell layer, and the voltage detection tab is exposed to the outside of the resin group. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-5163 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the bipolar battery, a detection wire such as a voltage detection tab is drawn from the inside of the battery element to the outside through the sealing material. In this case, the detection wire draw-out position in the sealing material may be more likely to break when the internal pressure of the cell layer increases than other parts of the sealing material. If the detection wire draw-out position in the sealing material breaks, for example, the external detection wires may short-circuit each other via the electrolyte, leading to a decrease in reliability.

[0005] An object of the present disclosure is to provide an electricity storage device capable of suppressing a decrease in reliability. [Means for solving the problem]

[0006] The energy storage device of the present disclosure comprises a laminate constructed by stacking a plurality of electrodes, each of which includes a current collector and an active material layer provided on the current collector; a sealing portion surrounding the laminate and sealing between adjacent electrodes in the stacking direction of the laminate; a plurality of detection wires connected to the electrodes and drawn out from the sealing portion; and a cooling member in contact with the laminate and having a cooling flow path for circulating a cooling fluid from an inlet to an outlet in a direction intersecting the stacking direction, the sealing portion including a draw-out portion from which each of the plurality of detection wires is drawn out, the draw-out portion being located closer to the inlet than to the outlet of the cooling flow path when viewed in the stacking direction.

[0007] In this power storage device, the electrode stack is provided with a sealing portion that seals between adjacent electrodes in the stacking direction, and the sealing portion is provided with a lead-out portion from which a plurality of detection lines are led out to the outside of the stack. In addition, this power storage device is provided with a cooling member having a cooling flow path that circulates a cooling fluid in a direction intersecting the stacking direction. The lead-out portion of the detection line in the sealing portion is located closer to the inlet of the cooling flow path than the outlet. In the cooling flow path, the temperature of the cooling fluid is lower on the inlet side than on the outlet side, and the cooling efficiency is higher. Therefore, even if the temperature inside the stack rises for some reason, the temperature of the lead-out portion close to the inlet of the cooling flow path is less likely to rise compared to other parts of the sealing portion. Therefore, the temperature of the sealing portion in the lead-out portion is suppressed from rising and softening the sealing portion. Also, inside the stack, the temperature of the electrode in the part close to the inlet of the cooling flow path is kept relatively low compared to the electrodes in other parts. Therefore, gas is less likely to be generated inside the stack in the part close to the inlet of the cooling flow path, and pressure is less likely to be applied to the sealing portion in the lead-out portion. Therefore, in the drawn-out portion, the seal is less likely to break when the internal pressure rises, and deterioration of reliability is suppressed.

[0008] In the energy storage device of the present disclosure, the sealing portion includes a plurality of outer surfaces extending along the stacking direction, the plurality of outer surfaces including a first outer surface on the inlet side, a second outer surface on the outlet side which is an outer surface different from the first outer surface, and a third outer surface extending between the first outer surface and the second outer surface, and the pull-out portion is provided on the third outer surface and may be located closer to the inlet than the outlet when viewed from the stacking direction.

[0009] In the energy storage device according to the present disclosure, the sealing portion includes a plurality of outer surfaces extending along the stacking direction, the plurality of outer surfaces including a first outer surface on the inlet side and a second outer surface on the outlet side that is different from the first outer surface, and the pull-out portion may be provided on the first outer surface.

[0010] In the energy storage device of the present disclosure, the inlet and outlet are arranged on the same side of the cooling member, the sealing portion includes a plurality of outer surfaces extending along the stacking direction, the plurality of outer surfaces including a first outer surface on the inlet and outlet side, and the pull-out portion is provided on the first outer surface and may be located closer to the inlet than the outlet when viewed from the stacking direction.

[0011] In the power storage device according to the present disclosure, the sealing portion may include a plurality of outer surfaces extending along the stacking direction, the drawn-out portion may be disposed on at least one of the plurality of outer surfaces, and adjacent drawn-out portions among the plurality of drawn-out portions in the stacking direction may be disposed at different positions in a direction intersecting the stacking direction and the extension direction of the detection line. In this case, accumulation of the thickness of the detection line along the stacking direction is avoided.

[0012] In the power storage device according to the present disclosure, the cooling member may be configured with a cooling flow path formed inside a conductive plate member, and may be in contact with and electrically connected to the outermost electrode in the stacking direction of the stack. In this case, by arranging the conductive cooling member in contact with the electrode of the outermost layer of the stack, the cooling member can be used as a conductive plate.

[0013] In the power storage device according to the present disclosure, the sealing portion may be provided on the peripheral portion of the current collector as viewed from the stacking direction, and the cooling member may extend over the peripheral portion of the current collector so as to overlap with the sealing portion as viewed from the stacking direction. In this case, the sealing portion is cooled, and a temperature rise is suppressed. Effect of the Invention

[0014] According to the present disclosure, it is possible to provide a power storage device capable of suppressing a decrease in reliability. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic cross-sectional view of a power storage device according to one embodiment. [Diagram 2] FIG. 2 is a schematic plan view of the power storage device shown in FIG. [Diagram 3] FIG. 3 is a schematic side view of the power storage device shown in FIG. [Figure 4] FIG. 4 is a schematic plan view showing an electricity storage device according to a modified example. [Diagram 5] FIG. 5 is a schematic plan view showing an electricity storage device according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. In the description of the drawings, the same elements or corresponding elements are given the same reference numerals, and duplicated descriptions may be omitted. In addition, each drawing may show an orthogonal coordinate system defined by an X-axis, a Y-axis, and a Z-axis.

[0017] Fig. 1 is a schematic cross-sectional view of an electricity storage device according to one embodiment. The electricity storage device 1 shown in Fig. 1 is an electricity storage module used in batteries of various vehicles such as forklifts, hybrid cars, and electric cars. The electricity storage device 1 is a secondary battery such as a nickel-metal hydride secondary battery or a lithium-ion secondary battery. The electricity storage device 1 may be an electric double layer capacitor or an all-solid-state battery. In this embodiment, the electricity storage device 1 is a lithium-ion secondary battery.

[0018] The energy storage device 1 includes an electrode stack (stack) 10, a sealing portion 20, a pair of cooling members 30, and a plurality of detection lines 40. The electrode stack 10 includes a plurality of bipolar electrodes (electrodes) 11, a negative terminal electrode (electrode) 12, a positive terminal electrode (electrode) 13, and a plurality of separators 14.

[0019] The bipolar electrode 11 has a current collector 15, a positive electrode active material layer (active material layer) 16, and a negative electrode active material layer (active material layer) 17. The current collector 15 has, for example, a sheet shape. The current collector 15 has, for example, a rectangular shape when viewed from the Z-axis direction. The positive electrode active material layer 16 is provided on one surface 15a of the current collector 15. The positive electrode active material layer 16 has, for example, a rectangular shape when viewed from the Z-axis direction. The negative electrode active material layer 17 is provided on the other surface 15b of the current collector 15. The negative electrode active material layer 17 has, for example, a rectangular shape when viewed from the Z-axis direction.

[0020] The negative electrode active material layer 17 is slightly larger than the positive electrode active material layer 16 when viewed from the Z-axis direction. That is, in a plan view viewed from the Z-axis direction, the entire region where the positive electrode active material layer 16 is formed is located within the region where the negative electrode active material layer 17 is formed. The multiple bipolar electrodes 11 are stacked along the Z-axis direction such that the positive electrode active material layer 16 and the negative electrode active material layer 17 face each other.

[0021] The negative electrode terminal electrode 12 has a current collector 15 and a negative electrode active material layer 17. The negative electrode terminal electrode 12 does not have a positive electrode active material layer 16. That is, no active material layer is provided on one surface 15a of the current collector 15 of the negative electrode terminal electrode 12. One surface 15a of the current collector 15 of the negative electrode terminal electrode 12 is exposed. The negative electrode terminal electrode 12 is disposed on one side in the Z-axis direction with respect to the multiple bipolar electrodes 11. The negative electrode active material layer 17 of the negative electrode terminal electrode 12 faces the positive electrode active material layer 16 of the bipolar electrode 11 located at one end in the Z-axis direction.

[0022] The positive terminal electrode 13 has a current collector 15 and a positive active material layer 16. The positive terminal electrode 13 does not have a negative active material layer 17. That is, no active material layer is provided on the other surface 15b of the current collector 15 of the positive terminal electrode 13. The other surface 15b of the current collector 15 of the positive terminal electrode 13 is exposed. The positive terminal electrode 13 is disposed on the other side in the Z-axis direction with respect to the multiple bipolar electrodes 11. The positive active material layer 16 of the positive terminal electrode 13 faces the negative active material layer 17 of the bipolar electrode 11 located at the other end in the Z-axis direction.

[0023] The separator 14 is disposed between adjacent bipolar electrodes 11, between the negative electrode terminal electrode 12 and the bipolar electrode 11, and between the positive electrode terminal electrode 13 and the bipolar electrode 11. The separator 14 is interposed between the positive electrode active material layer 16 and the negative electrode active material layer 17. The separator 14 separates the positive electrode active material layer 16 and the negative electrode active material layer 17, thereby preventing short circuits caused by contact between adjacent electrodes and allowing charge carriers such as lithium ions to pass through. In this manner, the electrode stack 10 is formed by stacking a plurality of electrodes (bipolar electrodes 11, negative electrode terminal electrodes 12, and positive electrode terminal electrodes 13) via the separators 14. Here, the Z-axis direction is the stacking direction of the electrodes in the electrode stack 10.

[0024] The current collector 15 is a chemically inactive electrical conductor for continuously passing a current through the positive electrode active material layer 16 and the negative electrode active material layer 17 during discharging or charging of the lithium ion secondary battery. The material of the current collector 15 is, for example, a metal material, a conductive resin material, or a conductive inorganic material. Examples of the conductive resin material include resins in which a conductive filler is added to a conductive polymer material or a non-conductive polymer material as necessary. The current collector 15 may have a plurality of layers. In this case, each layer of the current collector 15 may contain the above-mentioned metal material or conductive resin material.

[0025] A coating layer may be formed on the surface of the current collector 15. The coating layer may be formed by a known method such as plating or spray coating. The current collector 15 may be, for example, in the form of a plate, a foil (for example, a metal foil), a film, or a mesh. Examples of the metal foil include aluminum foil, copper foil, nickel foil, titanium foil, and stainless steel foil. Examples of the stainless steel foil include SUS304, SUS316, and SUS301 as specified in JIS G 4305:2015. By using stainless steel foil as the current collector 15, the mechanical strength of the current collector 15 can be ensured. The current collector 15 may be an alloy foil or clad foil of the above metals. When the current collector 15 is in the form of a foil, the thickness of the current collector 15 may be, for example, 1 μm to 100 μm.

[0026] The positive electrode active material layer 16 contains a positive electrode active material capable of absorbing and releasing charge carriers such as lithium ions. Examples of the positive electrode active material include lithium composite metal oxides having a layered rock salt structure, metal oxides having a spinel structure, polyanion compounds, and the like. The positive electrode active material may be any material that can be used in lithium ion secondary batteries. The positive electrode active material layer 16 may contain a plurality of positive electrode active materials. In this embodiment, the positive electrode active material layer 16 contains olivine-type lithium iron phosphate (LiFePO4) as a composite oxide.

[0027] The negative electrode active material layer 17 includes a negative electrode active material capable of absorbing and releasing charge carriers such as lithium ions. The negative electrode active material may be any of a simple substance, an alloy, or a compound. Examples of the negative electrode active material include Li, carbon, and metal compounds. The negative electrode active material may be an element capable of being alloyed with lithium or a compound thereof. Examples of carbon include natural graphite, artificial graphite, hard carbon (hardly graphitizable carbon), and soft carbon (easily graphitizable carbon). Examples of artificial graphite include highly oriented graphite and mesocarbon microbeads. Examples of elements capable of being alloyed with lithium include silicon and tin. In this embodiment, the negative electrode active material layer 17 includes graphite as a carbon-based material.

[0028] Each of the positive electrode active material layer 16 and the negative electrode active material layer 17 (hereinafter also simply referred to as "active material layer") may further contain, as necessary, a conductive assistant for enhancing electrical conductivity, a binder, an electrolyte (polymer matrix, ion-conductive polymer, electrolyte solution, etc.), an electrolyte supporting salt (lithium salt) for enhancing ion conductivity, etc. The conductive assistant is added to enhance the conductivity of each electrode. Examples of the conductive assistant include acetylene black, carbon black, graphite, etc.

[0029] The components contained in the active material layer or the blending ratio of the components and the thickness of the active material layer are not particularly limited, and conventionally known knowledge about lithium ion secondary batteries may be appropriately referred to. The thickness of the active material layer is, for example, 2 to 150 μm. The active material layer may be formed on the surface of the current collector 15 by a known method such as a roll coating method. A heat-resistant layer may be provided on the surface (one side or both sides) of the current collector 15 or the surface of the active material layer in order to improve the thermal stability of each electrode. The heat-resistant layer contains, for example, inorganic particles and a binder, and may also contain additives such as a thickener.

[0030] Examples of the binder include fluorine-containing resins such as polyvinylidene fluoride, polytetrafluoroethylene, and fluorine rubber, thermoplastic resins such as polypropylene and polyethylene, imide resins such as polyimide and polyamideimide, alkoxysilyl group-containing resins, acrylic resins such as acrylic acid or methacrylic acid, styrene-butadiene rubber (SBR), carboxymethyl cellulose, alginates such as sodium alginate and ammonium alginate, water-soluble cellulose ester crosslinked bodies, and starch-acrylic acid graft polymers. These binders can be used alone or in combination. Examples of the solvent include water and N-methyl-2-pyrrolidone (NMP).

[0031] The separator 14 may be, for example, a porous sheet or nonwoven fabric containing a polymer that absorbs and retains an electrolyte. Examples of materials for the separator 14 include polypropylene, polyethylene, polyolefin, and polyester. The separator 14 may have a single-layer structure or a multilayer structure. The multilayer structure may have, for example, a ceramic layer as an adhesive layer or a heat-resistant layer. The separator 14 may be impregnated with an electrolyte. The separator 14 may be composed of an electrolyte such as a polymer electrolyte or an inorganic electrolyte. Examples of the electrolyte impregnated in the separator 14 include a liquid electrolyte (electrolytic solution) containing a nonaqueous solvent and an electrolyte salt dissolved in the nonaqueous solvent, and a polymer gel electrolyte containing an electrolyte held in a polymer matrix.

[0032] When the separator 14 is impregnated with an electrolytic solution, the electrolyte salt may be a known lithium salt such as LiClO4, LiAsF6, LiPF6, LiBF4, LiCF3SO3, LiN(FSO2)2, or LiN(CF3SO2)2. The non-aqueous solvent may be a known solvent such as cyclic carbonates, cyclic esters, chain carbonates, chain esters, or ethers. Two or more of these known solvent materials may be used in combination.

[0033] The sealing portion 20 is formed on the periphery of the electrode stack 10. The sealing portion 20 is bonded to at least one of the one surface 15a and the other surface 15b of each current collector 15 at the periphery of each current collector 15. In this embodiment, the sealing portion 20 is bonded to both the one surface 15a and the other surface 15b of the current collector 15. The periphery of the current collector 15 is embedded in the sealing portion 20. The sealing portion 20 surrounds the electrode stack 10 when viewed from the Z-axis direction and seals the storage space S between each electrode. An electrolyte is stored in the storage space S. The sealing portion 20 prevents the electrolyte from penetrating to the outside. The sealing portion 20 prevents moisture and the like from entering the storage space S from the outside of the energy storage device 1. The sealing portion 20 prevents, for example, gas generated in each electrode due to a charge / discharge reaction or the like from leaking to the outside of the energy storage device 1. The edge of each separator 14 may be embedded in a sealing portion 20 .

[0034] The sealing portion 20 includes an insulating material. The sealing portion 20 prevents short circuits between the electrodes by insulating the electrodes from each other. Examples of materials for the sealing portion 20 include various resin materials such as polyethylene, polystyrene, ABS resin, modified polypropylene, and AS resin.

[0035] FIG. 2 is a schematic plan view of the electricity storage device shown in FIG. 1. As shown in FIGS. 1 and 2, the cooling member 30 is in contact with the electrode laminate 10 and has a cooling flow path 32 that circulates a cooling fluid (e.g., air) from an inlet 32a to an outlet 32b in a direction F (here, the X-axis direction) intersecting the Z-axis direction, and is a member for cooling the electrode laminate 10. The cooling member 30 includes a cooling member 30A disposed at one end of the electrode laminate 10 in the Z-axis direction, and a cooling member 30B disposed at the other end of the electrode laminate 10 in the Z-axis direction. The cooling member 30A is in contact with the current collector 15 of the negative terminal electrode 12 and is electrically connected to the negative terminal electrode 12. The cooling member 30B is in contact with the current collector 15 of the positive terminal electrode 13 and is electrically connected to the positive terminal electrode 13.

[0036] The cooling member 30 (cooling members 30A and 30B) includes a main body 31, a plurality of cooling channels 32, and a detection line 33. The main body 31 is, for example, made of metal, has electrical conductivity, and has, for example, a rectangular plate shape. The cooling channel 32 has an inlet 32a at one end on the upstream side in the direction F, and an outlet 32b at the other end on the downstream side in the direction F. The cooling channel 32 is a through hole formed in the main body 31. Here, the cooling channel 32 extends linearly along the X-axis direction, but may be bent. As an example, the plurality of cooling channels 32 are formed at equal intervals and parallel to each other. The detection line 33 is provided at one end of the main body 31 and is electrically connected to the main body 31.

[0037] In this manner, the cooling member 30 is configured with the cooling flow passage 32 formed inside the conductive plate member (main body portion 31), and is in contact with and electrically connected to the outermost electrode (negative terminal electrode 12 or positive terminal electrode 13) in the Z-axis direction of the electrode stack 10. This makes it possible to detect the battery state (e.g., voltage) of the power storage cell configured by the negative terminal electrode 12 and the bipolar electrode 11 adjacent to the negative terminal electrode 12, for example, by using the detection wire 33 of the cooling member 30A and a detection wire 40 (described in detail below) adjacent to the detection wire 33 in the Z-axis direction.

[0038] Moreover, by using the detection wire 33 of the cooling member 30B and the detection wire 40 adjacent to the detection wire 33 in the Z-axis direction, it is possible to detect the battery state (e.g., voltage) of the power storage cell constituted by the positive terminal electrode 13 and the bipolar electrode 11 adjacent to the positive terminal electrode 13. Therefore, the detection wire 33 can be used to detect the battery state, such as the voltage of the power storage cell. Furthermore, the cooling member 30 can also function as a conductive plate for electrically connecting the power storage devices 1 together when a plurality of power storage devices 1 are stacked along the Z-axis direction. In that case, one cooling member 30 may be shared between the power storage devices 1 adjacent to each other.

[0039] The cooling member 30 has a function of transmitting a restraining load to the electrode stack 10 when restraining the electricity storage device 1 in the Z-axis direction using a predetermined restraining member. Therefore, the cooling member 30 extends so as to overlap at least the central portion of the current collector 15 where the active material layer is formed, as viewed from the Z-axis direction. Furthermore, in this embodiment, the cooling member 30 extends from the central portion of the current collector to the peripheral portion of the current collector 15 so as to overlap the sealing portion 20 as viewed from the Z-axis direction.

[0040] In this embodiment, the thickness of the electrode laminate 10 in the Z-axis direction is made thicker in the region where the active material layer is formed than in the region where the sealing portion 20 is formed. Therefore, a restraining load is mainly applied from the cooling member 30 to the active material layer of the electrode laminate 10. In the example of FIG. 1, the region where the active material layer of the electrode laminate 10 is formed is formed, so that the electrode laminate 10 is compressed in the Z-axis direction, and the cooling member 30 and the sealing portion 20 are in contact with each other. Note that, in this embodiment, when viewed from the Z-axis direction, the outer edge of the cooling member 30 is located inside the outer edge of the sealing portion 20, and the outer edge of the cooling member 30 is located outside the inner edge of the sealing portion 20. However, the size of the cooling member 30 is not limited to this, and the outer edge of the cooling member 30 may be the same as the outer edge of the sealing portion 20, or may be located outside the outer edge of the sealing portion 20.

[0041] The detection wire 40 is provided in the electrode laminate 10 and is drawn from the sealing portion 20 to the outside of the electrode laminate 10. More specifically, a part of the detection wire 40 is embedded in the sealing portion 20, and the remaining part is drawn from the sealing portion 20 to the outside. The detection wire 40 is joined (for example, welded) to the current collector 15 of the electrode laminate 10 at the part embedded in the sealing portion 20 and electrically connected. As an example, the detection wire 40 is provided for the current collector 15 of all the bipolar electrodes 11. This makes it possible to detect the battery state (for example, voltage) of the storage cell composed of the bipolar electrodes 11 adjacent to each other by using a pair of detection wires 40 adjacent to each other in the Z-axis direction. Thus, as an example, the detection wire 40 is a voltage detection wire.

[0042] As described above, in this embodiment, a portion of the detection wire 40 is embedded in the sealing portion 20 and joined to the current collector 15 that is also embedded in the sealing portion 20. Therefore, a penetration portion is formed in the sealing portion 20 by the detection wire 40 and the current collector 15. The current collector 15 and the detection wire 40 are joined (e.g., welded) to the sealing portion 20 at the portion embedded in the sealing portion 20. As a result, the sealing of the storage space S is maintained even at the drawn-out portion 20p of the detection wire 40 in the sealing portion 20 (the penetration portion of the current collector 15 and the detection wire 40).

[0043] As shown in Fig. 2, the outer shape of the energy storage device 1 when viewed from the Z-axis direction is determined by the sealing portion 20. In other words, the sealing portion 20 includes a plurality of (here, two) outer surfaces 20a and a plurality of (here, two) outer surfaces 20b. The outer shape of the sealing portion 20 when viewed from the Z-axis direction is a rectangle having a short side and a long side. The outer surface 20a is a surface corresponding to the short side, and the outer surface 20b is a surface corresponding to the long side. When viewed from the Z-axis direction, the cooling flow path 32 extends along the outer surface 20a corresponding to the short side.

[0044] Here, the detection line 40 is drawn out from the outer surface 20a corresponding to the short side to the outside of the sealing part 20. In other words, the drawn-out portion 20p of the detection line 40 in the sealing part 20 is provided on the outer surface 20a. In particular, the drawn-out portion 20p is located closer to the inlet 32a than the outlet 32b of the cooling flow path 32 when viewed from the Z-axis direction. That is, the drawn-out portion 20p is located at least closer to the inlet 32a than the position (1 / 2 point of the whole) between the inlet 32a and the outlet 32b of the cooling fluid of the cooling flow path 32. Furthermore, as an example, the drawn-out portion 20p may be disposed closer to the inlet 32a than the position (1 / 4 point of the whole) between the 1 / 2 point of the cooling flow path 32 and the inlet 32a. Alternatively, the drawn-out portion 20p may be located closer to the inlet 32a than the position (1 / 3 point of the whole) of the cooling flow path 32.

[0045] Thus, the sealing portion 20 includes a plurality of outer surfaces 20a, 20b extending along the Z-axis direction. The plurality of outer surfaces 20a, 20b include a first outer surface (one of the outer surfaces 20b) on the inlet 32a side, a second outer surface (the other of the outer surfaces 20b) on the outlet 32b side, and a third outer surface (outer surface 20a) extending between the first outer surface and the second outer surface so as to connect the first outer surface and the second outer surface. The lead-out portion 20p is provided on the third outer surface and is located closer to the inlet 32a than the outlet 32b when viewed from the Z-axis direction.

[0046] Here, the definition of each outer surface will be clearly stated. That is, when a certain outer surface of the multiple outer surfaces 20a, 20b of the sealing part 20 is the inlet 32a side (or the exhaust port 32b side), it means that the outer surface of the sealing part 20 is an outer surface facing the same side as the outer surface where the inlet 32a opens (or the outer surface where the exhaust port 32b opens) among the outer surfaces extending along the Z-axis direction of the main body part 31 of the cooling member 30. As an example, in the example shown in FIG. 2, one outer surface A of the outer surfaces 20b of the sealing part 20 faces the negative side in the X-axis direction, similar to the outer surface B where the inlet 32a of the main body part 31 of the cooling member 30 opens, and is therefore the outer surface on the inlet 32a side. On the other hand, the other outer surface C of the outer surfaces 20b of the sealing part 20 faces the positive side in the X-axis direction opposite to the outer surface B, and is therefore not the outer surface on the inlet 32a side. In other words, the other outer surface C of the outer surfaces 20b of the sealing portion 20 faces the positive side in the X-axis direction, just like the outer surface D where the exhaust outlet 32b of the main body portion 31 of the cooling member 30 opens, and is therefore the outer surface on the exhaust outlet 32b side.

[0047] 3 is a schematic side view of the energy storage device 1 shown in FIG. 1. As shown in FIG. 3, among the multiple drawn-out portions 20p, adjacent ones in the Z-axis direction are arranged at different positions in the X-axis direction intersecting the Z-axis direction and the Y-axis direction in which the detection line 40 extends. In the example of FIG. 3, the multiple drawn-out portions 20p are arranged alternately along the Z-axis direction. Therefore, about half of the multiple drawn-out portions 20p are arranged at the same position in the X-axis direction. However, the arrangement of the drawn-out portions 20p is not limited thereto, and the position in the X-axis direction may be different for every three drawn-out portions 20p, or the positions in the X-axis direction of all the drawn-out portions 20p may be different.

[0048] As described above, in the energy storage device 1, the electrode stack 10 is provided with the sealing portion 20 that seals between the electrodes adjacent to each other in the Z-axis direction, and the sealing portion 20 is provided with the lead-out portion 20p from which the detection wires 40 are led out to the outside of the electrode stack 10. The energy storage device 1 also includes a cooling member 30 having a cooling flow passage 32 that circulates the cooling fluid in a direction intersecting the Z-axis direction. The lead-out portion 20p of the detection wire 40 in the sealing portion 20 is located closer to the inlet 32a than the outlet 32b of the cooling fluid of the cooling flow passage 32. In the cooling flow passage 32, the temperature of the cooling fluid is lower on the inlet 32a side than on the outlet 32b side, and the cooling efficiency is higher. Therefore, even if the temperature inside the electrode stack 10 rises for some reason, the temperature of the lead-out portion 20p located near the inlet 32a of the cooling flow passage 32 is less likely to rise than other portions of the sealing portion 20. Therefore, the temperature of the sealing portion 20 is prevented from rising in the lead-out portion 20p and the sealing portion 20 is prevented from softening. Also, inside the electrode stack 10, the temperature of the electrodes near the inlet 32a of the cooling flow passage 32 is kept relatively lower than that of the electrodes in other parts. Therefore, inside the electrode stack 10, gas is unlikely to be generated in the part near the inlet 32a of the cooling flow passage 32, so pressure is unlikely to be applied to the sealing portion 20 in the drawn-out portion 20p. Therefore, in the drawn-out portion 20p, the sealing portion 20 is unlikely to break when the internal pressure rises, and a decrease in reliability is suppressed.

[0049] In the energy storage device 1, the sealing portion 20 includes a plurality of outer surfaces 20a, 20b extending along the Z-axis direction, and the drawn-out portion 20p is disposed on at least one of the outer surfaces 20a, 20b. Among the plurality of embedded portions, the drawn-out portions 20p adjacent to each other in the Z-axis direction are disposed at different positions in the X-axis direction. This prevents the thickness of the detection line 40 from accumulating along the stacking direction.

[0050] Moreover, in the energy storage device 1, the cooling member 30 is configured with a cooling flow path 32 formed inside a conductive plate member (main body portion 31), and abuts against and is electrically connected to the outermost electrode in the Z-axis direction of the electrode stack 10. For this reason, the cooling member 30 can be used as a conductive plate that can be used for electrical connection between energy storage devices 1 and for detecting the battery state, such as the voltage of the energy storage cell.

[0051] Furthermore, in the energy storage device 1, the sealing portion 20 is provided on the peripheral portion of the current collector 15 as viewed from the Z-axis direction, and the cooling member 30 extends over the peripheral portion of the current collector 15 so as to overlap with the sealing portion 20 as viewed from the Z-axis direction. This allows the sealing portion 20 to be cooled, suppressing a temperature rise.

[0052] The above embodiment describes one aspect of the present disclosure. Therefore, the power storage device according to the present disclosure is not limited to the above-described power storage device and may be modified.

[0053] Fig. 4 is a schematic plan view showing an energy storage device according to a modified example. As shown in Fig. 4, in the energy storage device 1, of a pair of outer side surfaces 20b corresponding to the long sides of the sealing portion 20 when viewed from the Z-axis direction, the outer side surface 20b located on the inlet 32a side of the cooling flow channel 32 may be provided with an extended portion 20p of the sealing portion 20. In other words, the detection line 40 may be extended from the outer side surface 20b.

[0054] That is, the sealing portion 20 includes a plurality of outer surfaces 20a, 20b extending along the Z-axis direction, and the plurality of outer surfaces 20a, 20b include a first outer surface (one of the outer surfaces 20b) on the inlet 32a side and a second outer surface (the other of the outer surfaces 20b) different from the first outer surface and on the outlet 32b side. The drawn-out portion 20p is provided on the first outer surface. As a result, the drawn-out portion 20p is located closer to the inlet 32a than the outlet 32b when viewed from the Z-axis direction.

[0055] In this case, the drawn-out portion 20p is disposed at a location where the temperature of the cooling fluid is lower, and the cooling is facilitated. Furthermore, the drawn-out portion 20p may be disposed in a distributed manner on the multiple outer surfaces 20a, 20b in a range closer to the inlet 32a than to the outlet 32b of the cooling flow path 32. Furthermore, in the cooling member 30, the cooling flow path 32 may extend along the long side of the sealing portion 20.

[0056] In the above embodiment, the cooling member 30 extends from the central portion of the current collector 15 to the peripheral portion of the current collector 15 so as to overlap the sealing portion 20. However, the cooling member 30 may be provided in the central portion of the current collector 15 so as to overlap the active material layer when viewed from the Z-axis direction, but not to reach the sealing portion 20. In this case, the outer edge of the cooling member 30 is located inside the inner edge of the sealing portion 20 when viewed from the Z-axis direction. In this case, the cooling member 30 can transmit the restraining load of the electrode stack 10 without coming into contact with the sealing portion 20.

[0057] In the above embodiment, the cooling member 30 is in contact with and electrically connected to the outermost electrode in the Z-axis direction of the electrode stack 10. However, the cooling member 30 does not have to be electrically connected to the electrode stack 10. For example, the cooling member 30 may be configured to include an insulating member interposed between the cooling member 30 and the electrode stack 10, and may be in contact with the electrode stack 10 via the insulating member.

[0058] In the above embodiment, a part of the detection wire 40 is embedded in the sealing portion 20, and the remaining part is drawn out from the sealing portion 20 to the outside. However, the detection wire 40 may pass through the sealing portion 20. In this case, the detection wire 40 includes a part embedded in the sealing portion 20, another part drawn out from the part to the outside of the sealing portion 20, and another part drawn from the part into the inside of the sealing portion 20 (inside the storage space S). Furthermore, the detection wire 40 is not limited to being formed separately from the current collector 15 and joined to the current collector 15, but may be formed by extending a part of the current collector 15. Furthermore, the detection wire 40 is not limited to being a voltage detection wire, and may be, for example, a temperature detection wire connected to a temperature sensor provided in the electrode stack 10.

[0059] Furthermore, in the above embodiment, an example has been shown in which the adjacent drawn-out portions 20p in the Z-axis direction among the multiple drawn-out portions 20p are arranged at different positions in the X-axis direction. However, if the thickness of the detection line 40 does not affect the drawn-out portions 20p, the positions of the drawn-out portions 20p in the X-axis direction do not need to be different (they may be arranged in a row in the Z-axis direction).

[0060] Here, FIG. 5 is a schematic plan view showing an electric storage device according to a modified example. As shown in FIG. 5, the electric storage device 1 can be provided with a cooling member 50 instead of the cooling member 30. In this case, the electric storage device 1 can be provided with a cooling member 50 corresponding to the cooling member 30A and a cooling member 50 corresponding to the cooling member 30B. However, only one of the cooling member 30A and the cooling member 30B may be the cooling member 50. The cooling member 50, like the cooling member 30, is in contact with the electrode stack 10 and has a cooling flow path 32 that circulates a cooling fluid (e.g., air) from an inlet 32a to an outlet 32b in a direction F (here, a direction along the XY plane) intersecting the Z-axis direction, and is a member for cooling the electrode stack 10.

[0061] The cooling member 50 includes a main body 31, a cooling flow path 32, and a detection line 33 (not shown here). The cooling flow path 32 has an inlet 32a at one end on the upstream side in the direction F, and an outlet 32b at the other end on the downstream side in the direction F. The cooling flow path 32 here extends while being partially bent along the XY plane. More specifically, the cooling flow path 32 includes a first portion 32A extending linearly from the inlet 32a along the Y-axis direction, a second portion 32B extending linearly along the Y-axis direction toward the outlet 32b, and a third portion 32C extending while being bent in an arc shape and connecting the first portion 32A and the second portion 32B. The first portion 32A and the second portion 32B extend approximately parallel to each other.

[0062] As a result, the inlet 32a and the outlet 32b are disposed on the same side of the main body 31. In this example, the inlet 32a and the outlet 32b are both disposed on the outer surface 20a side on which the lead-out portion 20p of the detection line 40 in the sealing portion 20 is provided.

[0063] That is, the inlet 32a and the outlet 32b are disposed on the same side of the cooling member 30. The sealing portion 20 includes a plurality of outer surfaces 20a, 20b extending along the Z-axis direction, and the plurality of outer surfaces 20a, 20b include a first outer surface (one of the outer surfaces 20a) on the inlet 32a and outlet 32b side. The drawn-out portion 20p is provided on the first outer surface and is located closer to the inlet 32a than the outlet 32b when viewed from the Z-axis direction.

[0064] However, the inlet 32a and the outlet 32b may be disposed on the outer surface 20b side. In this case, the lead-out portion 20p of the detection line 40 may be provided on the outer surface 20b.

[0065] In this example, the drawn-out portion 20p of the detection line 40 is also located closer to the inlet 32a than the outlet 32b when viewed from the Z-axis direction. In the example shown by the solid line in Fig. 5, the drawn-out portion 20p is located closer to the end of the outer surface 20a opposite the outlet 32b than the inlet 32a. However, the drawn-out portion 20p may be located closer to the inlet 32a than the outlet 32b between the inlet 32a and the outlet 32b when viewed from the Z-axis direction. Furthermore, the drawn-out portion 20p may be located so as to at least partially overlap the inlet 32a (overlap in the X-axis direction) when viewed from the Z-axis direction.

[0066] As described above, even when the cooling member 50 is used, it is possible to achieve the same effects as when the cooling member 30 is used. In particular, by using the cooling member 50, the inlet 32a and the outlet 32b of the cooling flow path 32 are arranged on the same side of the main body 31, so that the mechanism for introducing and discharging the cooling fluid to and from the cooling flow path 32 can be arranged on one side of the electricity storage device 1, thereby simplifying the mechanism. [Industrial Applicability]

[0067] An electricity storage device capable of suppressing a decrease in reliability is provided. [Explanation of symbols]

[0068] 1...electricity storage device, 10...electrode laminate (laminate), 15...current collector, 16...positive electrode active material layer (active material layer), 17...negative electrode active material layer, 20...sealing portion, 20a, 20b...outer surfaces, 20p...drawing portion, 30, 50...cooling member, 31...main body portion, 32...cooling flow path, 40...detection line.

Claims

1. a laminate including a current collector and a plurality of electrodes each including an active material layer provided on the current collector; a sealing portion that surrounds the laminate and seals the gaps between the electrodes that are adjacent to each other in a stacking direction of the laminate; a plurality of detection lines connected to the electrodes and drawn out from the sealing portion; a cooling member in contact with the stack and having a cooling flow path for circulating a cooling fluid from an inlet to an outlet in a direction intersecting the stacking direction; Equipped with the sealing portion includes an extraction portion from which each of the plurality of detection lines is extracted, The extraction portion is located closer to the inlet than to the outlet of the cooling flow path when viewed from the stacking direction. Energy storage device.

2. The sealing portion includes a plurality of outer surfaces extending along the stacking direction, The plurality of outer surfaces include A first outer surface on the inlet side; A second outer surface which is different from the first outer surface and is located on the outlet side; a third outer surface extending between the first outer surface and the second outer surface; Including, The pull-out portion is provided on the third outer surface and is located closer to the inlet than the outlet when viewed from the stacking direction. The power storage device according to claim 1 .

3. The sealing portion includes a plurality of outer surfaces extending along the stacking direction, The plurality of outer surfaces include A first outer surface on the inlet side; A second outer surface which is different from the first outer surface and is located on the outlet side; Including, The pull-out portion is provided on the first outer surface. The power storage device according to claim 1 .

4. the inlet and the outlet are disposed on the same side of the cooling member, The sealing portion includes a plurality of outer surfaces extending along the stacking direction, The plurality of outer surfaces include a first outer surface on the inlet and outlet side, The pull-out portion is provided on the first outer surface and is located closer to the inlet than the outlet when viewed from the stacking direction. The power storage device according to claim 1 .

5. The sealing portion includes a plurality of outer surfaces extending along the stacking direction, the pull-out portion is disposed on at least one of the outer surfaces; Among the plurality of pull-out portions, the pull-out portions adjacent to each other in a stacking direction are disposed at different positions in a direction intersecting the stacking direction and an extension direction of the detection line. The power storage device according to claim 1 .

6. The cooling member is configured by forming the cooling flow path inside a conductive plate member, and is in contact with and electrically connected to the outermost electrode in the stacking direction of the stack. The power storage device according to any one of claims 1 to 5.

7. the sealing portion is provided on a peripheral portion of the current collector when viewed from the stacking direction, the cooling member extends over the peripheral portion of the current collector so as to overlap the sealing portion when viewed from the stacking direction. The power storage device according to any one of claims 1 to 5.

8. the sealing portion is provided on a peripheral portion of the current collector when viewed from the stacking direction, the cooling member extends over the peripheral portion of the current collector so as to overlap the sealing portion when viewed from the stacking direction. The power storage device according to claim 6.

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