Electricity storage unit

Abstract

The utility model provides an electric power storage unit in which the amount of non-aqueous electrolyte is distributed more uniformly. An electricity storage cell is provided with: an electrode laminate including a plurality of bipolar electrodes laminated with a separator interposed therebetween; a resin body that forms an accommodation space between adjacent bipolar electrodes among the plurality of bipolar electrodes; a non-aqueous electrolyte contained in the containing space; and a plurality of porous resin sheets. The bipolar electrode has a current collector having a resin body welded to the periphery thereof, a positive electrode layer formed on a first main surface of the current collector, and a negative electrode layer formed on a second main surface of the current collector, the second main surface being on the opposite side of the first main surface. The first main surface includes a first region not in contact with the positive electrode layer and the resin body. The second main surface includes a second region not in contact with the negative electrode layer and the resin body. The porous resin sheet has at least one of a first porous resin sheet disposed in at least a portion of the first region and a second porous resin sheet disposed in at least a portion of the second region.

Description

Technical Field

[0001] The utility model relates to a power storage unit. Background Art

[0002] Patent document 1 discloses a storage unit. The storage unit includes a positive electrode layer and a negative electrode layer, a separator, a spacer (hereinafter also referred to as a "resin body") and a reinforcing member. The positive electrode layer and the negative electrode layer have an active material layer on one side of a current collector made of a metal foil. The positive electrode layer and the negative electrode layer are arranged in a manner that the above-mentioned active material layers are opposite to each other. The separator is arranged between the above-mentioned positive electrode layer and the above-mentioned negative electrode layer, and is interposed between the above-mentioned active material layers. The spacer is arranged between the above-mentioned positive electrode layer and the above-mentioned negative electrode layer, and the edge of the above-mentioned current collector is sealed in a manner of surrounding the above-mentioned active material layer to form a storage space for containing an electrolyte (hereinafter also referred to as a "non-aqueous electrolyte"). The reinforcing member reinforces the uncoated portion of the above-mentioned current collector where the above-mentioned active material layer is not provided. The above-mentioned current collector has the above-mentioned uncoated portion between the above-mentioned spacer and the above-mentioned active material layer when observed from the relative direction of the above-mentioned active material layer in the above-mentioned positive electrode layer and the above-mentioned negative electrode layer. The reinforcing member is arranged along the uncoated portion so as to straddle a boundary between the active material layer and the uncoated portion and a boundary between the spacer and the uncoated portion when viewed from the opposing direction.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2022-069042

[0004] If there is air in the storage space, it may be difficult for the non-aqueous electrolyte to enter the storage space. Therefore, the storage space may be depressurized before the non-aqueous electrolyte is injected into the power storage cell.

[0005] The storage space of the storage unit disclosed in Patent Document 1 includes a space between the uncoated portion of the collector of the positive electrode layer and the negative electrode layer and the partition before the non-aqueous electrolyte is injected (hereinafter also referred to as "uncoated portion space"). Therefore, when the storage space is depressurized, due to the pressure difference between the pressure in the storage space and the atmospheric pressure, the collector may be pushed into the interior of the storage unit, and the uncoated portion space is reduced. If the non-aqueous electrolyte is injected in a state where the uncoated portion space is reduced, uneven distribution of the liquid amount of the non-aqueous electrolyte in the storage space may occur. In a portion where the liquid amount of the non-aqueous electrolyte is relatively small, if charging and discharging are performed, the non-aqueous electrolyte may be exhausted. If the non-aqueous electrolyte is exhausted, the battery reaction may be difficult to proceed. As a result, the charging characteristics of the storage unit may deteriorate. Utility Model Content

[0006] The present disclosure has been made in view of the above-mentioned actual situation. A problem to be solved by one embodiment of the present disclosure is to provide a power storage unit in which the amount of non-aqueous electrolyte is more uniformly distributed.

[0007] Means for solving the above-mentioned problems include the following embodiments.

[0008] The first mode of the present invention discloses a storage unit comprising an electrode stack including a plurality of bipolar electrodes stacked with a separator therebetween, a resin body forming a storage space between adjacent bipolar electrodes among the plurality of bipolar electrodes, a non-aqueous electrolyte contained in the storage space, and a plurality of porous resin sheets, the bipolar electrode comprising a collector to which the resin body is fused at the periphery, a positive electrode layer formed on a first main surface of the collector, and a negative electrode layer formed on a second main surface of the collector opposite to the first main surface, the first main surface comprising a first region that is not in contact with the positive electrode layer and the resin body, the second main surface comprising a second region that is not in contact with the negative electrode layer and the resin body, and the porous resin sheet comprising at least one of a first porous resin sheet arranged at at least a portion of the first region and a second porous resin sheet arranged at at least a portion of the second region.

[0009] In the first embodiment, the porous resin sheet has at least one of a first porous resin sheet and a second porous resin sheet. Therefore, in the state of the storage unit before the non-aqueous electrolyte is injected, when the storage space is depressurized, the support of the porous resin sheet makes it difficult for the collector to deform. As a result, the storage space is not easy to shrink compared with the past. Furthermore, the porous resin sheet is easy to retain the non-aqueous electrolyte inside it. As a result, the distribution of the liquid amount of the non-aqueous electrolyte in the storage space of the storage unit of the first embodiment is more uniform than before. Therefore, even if charging and discharging are repeated, local depletion of the non-aqueous electrolyte is not easy to occur in the storage space. That is, the charging characteristics of the storage unit of the first embodiment are easier to maintain than before.

[0010] An electricity storage cell according to a second aspect of the present disclosure is the electricity storage cell according to the first aspect, wherein the porous resin sheet includes one of the first porous resin sheet and the second porous resin sheet.

[0011] If the storage unit is repeatedly charged and discharged, gas (hereinafter also referred to as "internal gas") is sometimes generated in the storage space. In the second embodiment, the internal gas is easily accumulated in the space in the storage space where one of the first porous resin sheet and the second porous resin sheet is not formed. That is, compared with the structure in which the porous resin sheet has the first porous resin sheet and the second porous resin sheet, the internal gas is not easy to exist between the positive electrode layer and the negative electrode layer. Therefore, lithium metal is not easy to precipitate in at least one of the positive electrode layer and the negative electrode layer. As a result, the storage unit of the second embodiment further suppresses the occurrence of short circuit.

[0012] A third aspect of the present disclosure is the electricity storage cell according to the first or second aspect, wherein the first porous resin sheet has the same thickness as the positive electrode layer, and the second porous resin sheet has the same thickness as the negative electrode layer.

[0013] In the third aspect, when the storage space is depressurized in the state of the storage unit before the non-aqueous electrolyte is injected, the collector is easily supported by the porous resin sheet and is less likely to deform. As a result, the amount of non-aqueous electrolyte in the storage space of the storage unit of the third aspect is more evenly distributed.

[0014] A fourth aspect of the present disclosure is the electricity storage cell according to any one of the first to third aspects, wherein the first porous resin sheet is arranged throughout the first region, and the second porous resin sheet is arranged throughout the second region.

[0015] In the fourth aspect, in the state of the storage unit before the non-aqueous electrolyte is injected, when the storage space is depressurized, the collector is easily supported by the porous resin sheet and is less likely to deform. Therefore, the liquid amount of the non-aqueous electrolyte in the storage space of the storage unit of the fourth aspect is more uniformly distributed.

[0016] Fifth Aspect A fifth aspect of the present disclosure is the electricity storage cell according to any one of the first to fourth aspects, wherein the porous resin sheet contains polyolefin.

[0017] Polyolefin has excellent durability against non-aqueous electrolyte. The fifth embodiment of the power storage cell can maintain charging characteristics for a long period of time compared to a configuration in which the porous resin sheet does not contain polyolefin.

[0018] According to the present disclosure, there is provided a power storage unit in which the amount of nonaqueous electrolyte is more uniformly distributed. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a perspective view of the appearance of a power storage unit according to an embodiment of the present disclosure.

[0020] Figure 2 for Figure 1 Cross-sectional view along line II-II.

[0021] Figure 3 for Figure 2 A partial enlarged view of .

[0022] Figure 4 It is a cross-sectional view for explaining the method for manufacturing the power storage cell of the present disclosure.

[0023] Figure 5This is a cross-sectional view of a power storage unit precursor according to an embodiment of the present disclosure in a state where the housing space is depressurized. DETAILED DESCRIPTION

[0024] In the present disclosure, the numerical range represented by "to" refers to a range that includes the numerical values ​​recorded before and after "to" as the minimum and maximum values, respectively. In the numerical ranges recorded in stages in the present disclosure, the upper limit value or lower limit value recorded in a certain numerical range can be replaced by the upper limit value or lower limit value of other numerical ranges recorded in stages. In the present disclosure, a combination of two or more preferred modes is a more preferred mode. In the present disclosure, the term "process" is not only an independent process, but also is included in this term as long as the desired purpose of the process is achieved, even if it cannot be clearly distinguished from other processes.

[0025] Hereinafter, an embodiment of the electric storage unit battery of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding parts are given the same reference numerals, and their description will be omitted.

[0026] like Figure 1 As shown in FIG. 1 , the power storage unit 1 according to the embodiment of the present disclosure is a rectangular parallelepiped object. The power storage unit 1 includes an electrode stack 10, a resin body 20, a non-aqueous electrolyte (not shown), and a plurality of porous resin sheets 30 (see FIG. 1 ). Figure 2 ). The resin body 20 covers the side surfaces of the electrode stack 10 .

[0027] In the embodiment, one side of the length direction of the main surface of the storage cell 1 is defined as the positive direction of the X-axis, and the opposite side is defined as the negative direction of the X-axis. One side of the short side direction of the main surface of the storage cell 1 is defined as the positive direction of the Y-axis, and the opposite side is defined as the negative direction of the X-axis. One side of the thickness direction of the storage cell 1 is defined as the positive direction of the Z-axis, and the opposite side is defined as the negative direction of the Z-axis. The X-axis, Y-axis, and Z-axis are orthogonal to each other. The negative direction of the Z-axis is parallel to the direction of gravity. In addition, these directions do not limit the directions of the storage cell of the present disclosure when in use.

[0028] The length L1 of the power storage unit 1 in the X-axis direction (see Figure 1 ) and the length L2 in the Y-axis direction (refer to Figure 1 ) can exceed 1m respectively.

[0029] The electrode stack 10 is a rectangular parallelepiped. The electrode stack 10 includes a plurality of bipolar electrodes 11 stacked with a separator 12 interposed therebetween. Figure 2As shown, there are a plurality of bipolar electrodes 11, a plurality of separators 12, a positive electrode layer side terminal electrode 13, and a negative electrode layer side terminal electrode 14. The plurality of bipolar electrodes 11 and the plurality of separators 12 are alternately stacked in the axial direction. The positive electrode layer side terminal electrode 13 is stacked on the bipolar electrode 11 located most on one side of the stacking direction (the positive side in the Z-axis direction) among the plurality of bipolar electrodes 11 through the separator 12. The negative electrode layer side terminal electrode 14 is stacked on the bipolar electrode 11 located most on the other side of the stacking direction (the negative side in the Z-axis direction) among the plurality of bipolar electrodes 11 through the separator 12.

[0030] like Figure 3 As shown, the bipolar electrode 11 includes a current collector 110, a positive electrode layer 111, and a negative electrode layer 112. The periphery of the current collector 110 is welded to the resin body 20. The positive electrode layer 111 is formed on the first main surface S110A of the current collector 110. The negative electrode layer 112 is formed on the second main surface S110B of the current collector 110. The bipolar electrode 11 may be a known structure.

[0031] The current collector 110 supplies current to the positive electrode layer 111 and the negative electrode layer 112 during the discharge or charge of the power storage unit 1. Examples of the current collector 110 include aluminum foil, copper foil, nickel foil, titanium foil, stainless steel foil, and the like. A coating layer may be formed on the surface of the current collector 110 by a known method (e.g., plating, spraying, etc.). The thickness of the current collector 110 may be 1 μm to 100 μm.

[0032] The positive electrode layer 111 contains a positive electrode layer active material that can absorb and release charge carriers (e.g., lithium composite metal oxides with a layered rock salt structure, metal oxides with a spinel structure, polyanion compounds, etc.). As needed, the positive electrode layer 111 may also contain a conductive aid (e.g., carbon nanofibers, etc.) for improving electronic conductivity, a binder (e.g., polyvinylidene fluoride, etc.), an electrolyte supporting salt (lithium salt) for improving ion conductivity, a polymer electrolyte, and an additive (e.g., trifluoropropylene carbonate, a filler as a reinforcing material, etc.). The thickness L3 of the positive electrode layer 111 (see Figure 3 ) can be 2μm to 500μm.

[0033] The negative electrode layer 112 contains a negative electrode layer active material that can absorb and release charge carriers (e.g., carbon (e.g., natural graphite, artificial graphite), a compound that can alloy with lithium (e.g., silicon, tin, etc.), etc.). If necessary, the negative electrode layer 112 may also contain a conductive aid (e.g., acetylene black, etc.) for improving electronic conductivity, a binder (e.g., polyvinylidene fluoride, etc.), an electrolyte supporting salt (lithium salt) for improving ion conductivity, a polymer electrolyte, an additive (e.g., trifluoropropylene carbonate, a filler as a reinforcing material, etc.). The thickness L4 of the negative electrode layer 112 (see Figure 3) can be 2 μm to 500 μm. The thickness L4 of the negative electrode layer 112 can be the same as or different from the thickness L3 of the positive electrode layer 111. In this embodiment, the length L5 of the negative electrode layer 112 in the Y-axis direction (see Figure 3 ) is greater than the length L6 of the positive electrode layer 111 in the Y-axis direction (refer to Figure 3 )long.

[0034] The separator 12 maintains the spacing between the positive electrode layer 111 and the negative electrode layer 112 to prevent the occurrence of contact short circuit, and allows charge carriers such as lithium ions to pass through. The periphery of the separator 12 is fused to the resin body 20. The separator 12 is held by the resin body 20. As the separator 12, for example, a porous resin sheet or a non-woven fabric can be listed. As the material of the porous resin sheet, for example, polyolefins (polypropylene, polyethylene, etc.) can be listed. As the material of the non-woven fabric, for example, polypropylene, polyethylene terephthalate, methyl cellulose, etc. can be listed. The separator 12 can be a known structure.

[0035] The positive electrode layer side terminal electrode 13 includes a current collector 110 and a positive electrode layer 111. The positive electrode layer 111 is formed on the second main surface S110B of the current collector 110. The positive electrode layer side terminal electrode 13 may have a known structure.

[0036] The negative electrode layer side terminal electrode 14 includes a current collector 110 and a negative electrode layer 112. The negative electrode layer 112 is formed on the first main surface S110A of the current collector 110. The negative electrode layer side terminal electrode 14 may have a known structure.

[0037] The resin body 20 forms a housing space T between adjacent bipolar electrodes 11 among the plurality of bipolar electrodes 11. In the housing space T, the positive electrode layer 111, the negative electrode layer 112, the separator 12, and the porous resin sheet 30 are housed in a state contained in a non-aqueous electrolyte. In the present embodiment, the resin body 20 prevents the electrolyte housed in the housing space T from leaking to the outside. The resin body 20 can prevent moisture from intruding into the housing space T from the outside of the storage cell 1. The resin body 20 prevents internal gas generated from the positive electrode layer 111 or the negative electrode layer 112 due to charging and discharging, etc. from leaking to the outside of the storage cell 1.

[0038] The resin body 20 is a square tube-shaped object with a rectangular cross section. The resin body has a plurality of resin body segments 21 that hold the respective peripheries of the current collector 110 and the separator 12. The resin body segments 21 are arranged along the stacking direction (Z-axis direction) according to the current collector 110 and the separator 12. The resin body segments 21 are square tube-shaped objects with a rectangular cross section. The resin body segments 21 are fused to the periphery of the current collector 110. In the stacking direction, adjacent resin body segments 21 are fused to each other. Therefore, the periphery of the current collector 110 and the periphery of the separator 12 are respectively maintained in a state of being buried in the resin body 20. Examples of the material of the resin body 20 include polyethylene, polystyrene, acrylonitrile-butadiene-styrene copolymer resin (ABS resin), modified polypropylene, acrylonitrile styrene resin, and the like.

[0039] The non-aqueous electrolyte is contained in the containing space T. The non-aqueous electrolyte may include a non-aqueous solvent and a lithium salt. As the lithium salt, for example, LiClO4, LiAsF6, LiPF6, LiBF4, LiCF3SO3, LiN(FSO2)2, LiN(CF3SO2)2, etc. may be listed. As the non-aqueous solvent, cyclic carbonates, cyclic esters, chain carbonates, chain esters, ethers, etc. may be listed. The non-aqueous electrolyte may include additives (for example, lithium bis(oxalate)borate, etc.), etc.

[0040] The porous resin sheet 30 supports the current collector 110 and retains the non-aqueous electrolyte. The porous resin sheet 30 is a square tube-shaped object with a rectangular cross section.

[0041] like Figure 3 As shown, the first main surface S110A of the current collector 110 includes a first region RS110A that is not in contact with the positive electrode layer 111 and the resin body 20. The second main surface S110B of the current collector 110 includes a second region RS110B that is not in contact with the negative electrode layer 112 and the resin body 20. The porous resin sheet has a plurality of second porous resin pieces 31 arranged in the second region RS110B.

[0042] In this embodiment, the thickness L7 of the second porous resin sheet 31 (see Figure 3 ) is the same as the thickness L4 of the negative electrode layer 112. The thickness L7 of the second porous resin sheet 31 (see Figure 3 ) may be 2 μm to 500 μm. The second porous resin sheet 31 is arranged in the entire area of ​​the second region RS110B. The material of the porous resin sheet 30 is, for example, polyolefin (polypropylene, polyethylene, etc.).

[0043] The porosity of the porous resin sheet 30 is not particularly limited, but is preferably 30% to 50% by volume from the viewpoint of supporting the current collector 110 and retaining the non-aqueous electrolyte. The porosity represents the proportion (volume %) of the pores in the porous resin sheet 30. Specifically, the volume (cm 3 ) and mass (g), and calculate using the following formula (A):

[0044] Formula (A): Porosity (%) = (1-mass / (density x volume)) × 100

[0045] The power storage unit 1 can be used, for example, as a power source for electric four-wheeled vehicles, electric two-wheeled vehicles, portable devices, power storage systems, etc. Examples of electric four-wheeled vehicles include electric vehicles (BEV: Battery Electric Vehicle), plug-in hybrid electric vehicles (PHEV: Plug-in Hybrid Electric Vehicle), and hybrid electric vehicles (HEV: Hybrid Electric Vehicle). Electric two-wheeled vehicles include electric motorcycles or electric power-assisted bicycles. Examples of portable devices include smart phones, tablet computers, notebook computers, power tools, and cameras. Examples of power storage systems include household power storage systems, industrial power storage systems, and energy storage systems (ESS: Energy Storage System).

[0046] The method for manufacturing a storage cell according to an embodiment of the present disclosure includes a preparation step, a stacking step, a welding step, a decompression step, and a liquid injection step. The preparation step, the stacking step, the welding step, the decompression step, and the liquid injection step are performed in this order. Thus, the storage cell 1 is obtained.

[0047] In the preparation step, the bipolar electrode sheet 91 , the separator sheet 92 , the positive electrode layer terminal electrode sheet 93 , the negative electrode layer terminal electrode sheet 94 , and the porous resin sheet 30 are prepared.

[0048] The bipolar electrode sheet 91 includes a bipolar electrode 11 and a resin body segment 21 fused to the periphery of the current collector 110 of the bipolar electrode 11. The separator sheet 92 includes a separator 12 and a resin body segment 21 fused to the periphery of the separator 12. The positive electrode layer terminal electrode sheet 93 includes a positive electrode layer terminal electrode 13 and a resin body segment 21 fused to the periphery of the current collector 110 of the positive electrode layer terminal electrode 13. The negative electrode layer terminal electrode sheet 94 includes a negative electrode layer terminal electrode 14 and a resin body segment 21 fused to the periphery of the current collector 110 of the negative electrode layer terminal electrode 14. The bipolar electrode sheet 91, the separator sheet 92, the positive electrode layer terminal electrode sheet 93, the negative electrode layer terminal electrode sheet 94, and the porous resin sheet 30 may be prepared by any known method.

[0049] In the lamination step, the bipolar electrode sheet 91 , the separator sheet 92 , the positive electrode layer terminal electrode sheet 93 , the negative electrode layer terminal electrode sheet 94 , and the porous resin sheet 30 are laminated to obtain a laminated body.

[0050] Specifically, Figure 4 As shown, first, the porous resin sheet 30 is arranged on the negative electrode layer side terminal electrode sheet 94. Next, the lamination operation of arranging the separator sheet 92, the bipolar electrode sheet 91 and the porous resin sheet 30 in this order is repeated. Finally, the positive electrode layer side terminal electrode sheet 93 is arranged on the separator sheet 92. The lamination method can be any known method.

[0051] In the welding step, the resin body divided bodies 21 are heated and the adjacent resin body divided bodies 21 are welded to each other to obtain a storage cell precursor. By welding the adjacent resin body divided bodies 21 to each other, a plurality of resin body divided bodies 21 are integrated to form a resin body 20. The structure of the storage cell precursor is the same as that of the storage cell 1 except that the non-aqueous electrolyte is not included. The method for heating the stacked body can be any known method.

[0052] In the decompression step, the pressure in the storage space T of the storage cell precursor is reduced. As a result, the air in the storage space T is discharged to the outside of the storage cell precursor. As a result, the non-aqueous electrolyte is easily injected into the storage space T. The method of reducing the pressure in the storage space T can be any known method.

[0053] In the liquid injection step, a nonaqueous electrolyte is injected into the housing space T of the electricity storage cell precursor. In this way, the electricity storage cell 1 is obtained. The method of injecting the nonaqueous electrolyte may be any known method.

[0054] As reference Figure 1 to Figure 4 As described above, the power storage unit 1 includes: an electrode stack 10, 20 including a plurality of bipolar electrodes 11 stacked with a separator 12 interposed therebetween, a resin body, a non-aqueous electrolyte, and a plurality of porous resin sheets 30. The bipolar electrode 11 includes a current collector 110, a positive electrode layer 111, and a negative electrode layer 112. The porous resin sheet 30 includes a second porous resin sheet 31 disposed in the second region RS110B.

[0055] Therefore, in the power storage unit precursor, if the housing space T is depressurized, Figure 5As shown, due to the pressure difference between the pressure in the storage space T and the atmospheric pressure, the first region RS110A of the collector 110 of the terminal electrode 13 on the positive electrode layer side and the second region RS110B of the collector 110 of the terminal electrode 14 on the negative electrode layer side are pushed into the interior of the storage unit precursor. In the present embodiment, the collector 110 is not easily deformed under the support of the porous resin sheet 30. As a result, the storage space T is not easily reduced compared with the past. Furthermore, the porous resin sheet 30 can easily retain the non-aqueous electrolyte therein. As a result, the distribution of the liquid amount of the non-aqueous electrolyte in the storage space T of the storage unit 1 is more uniform than before. Therefore, even if charging and discharging are repeated, local depletion of the non-aqueous electrolyte is not likely to occur in the storage space T. That is, the charging characteristics of the storage unit 1 are easier to maintain than before.

[0056] As reference Figure 1 to Figure 4 As described above, the porous resin sheet 30 includes only the second porous resin sheet 31 .

[0057] When the storage cell is repeatedly charged and discharged, internal gas may be generated in the storage space T. The internal gas is likely to accumulate in the space P (see FIG. 1 ) where the second porous resin sheet 31 is not formed in the storage space T. Figure 3 ). That is, compared with the configuration in which the porous resin sheet 30 includes the first porous resin sheet and the second porous resin sheet 31 disposed in the space P, internal gas is less likely to exist between the positive electrode layer 111 and the negative electrode layer 112. Therefore, lithium metal is less likely to precipitate in at least one of the positive electrode layer 111 and the negative electrode layer 112. As a result, the storage cell 1 further suppresses the occurrence of a short circuit.

[0058] As reference Figure 1 to Figure 4 As described above, the thickness L7 of the second porous resin sheet 31 is the same as the thickness L4 of the negative electrode layer 112 .

[0059] Thus, in the storage cell precursor, when the housing space T is depressurized, the current collector 110 is easily supported by the porous resin sheet 30 and is less likely to deform than a configuration in which the thickness L7 of the second porous resin sheet 31 is not the same as the thickness L4 of the negative electrode layer 112. As a result, the amount of the nonaqueous electrolyte in the housing space T of the storage cell 1 is more uniformly distributed.

[0060] As reference Figure 1 to Figure 4 As described above, the second porous resin sheet 31 is arranged in the entire second region RS110B.

[0061] Thus, in the storage cell precursor, when the housing space T is depressurized, the current collector 110 is easily supported by the porous resin sheet 30 and is less likely to deform than a configuration in which the second porous resin sheet 31 is not disposed in the entire area of ​​the second region RS110B. Therefore, the distribution of the amount of the non-aqueous electrolyte in the housing space T of the storage cell 1 is more uniform.

[0062] As reference Figure 1 to Figure 4 As described above, the porous resin sheet 30 contains polyolefin.

[0063] Polyolefin has excellent durability against non-aqueous electrolytes. The power storage cell 1 can maintain charging characteristics for a long period of time compared to a configuration in which the porous resin sheet 30 does not contain polyolefin.

[0064] In the present embodiment, the porous resin sheet 30 has only the second porous resin sheet 31, but the present invention is not limited thereto. The porous resin sheet 30 may include, for example, a first porous resin sheet and a second porous resin sheet 31 disposed in at least a portion of the first region RS110A. The porous resin sheet 30 may include, for example, only the first porous resin sheet.

[0065] In the present embodiment, the thickness T7 of the second porous resin sheet 31 is the same as the thickness T4 of the negative electrode layer 112 , but the present invention is not limited thereto. The thickness T7 of the second porous resin sheet 31 may be different from the thickness T4 of the negative electrode layer 112 .

[0066] In the present embodiment, the second porous resin sheet 31 is disposed in the entire second region RS110B, but the present invention is not limited thereto and the second porous resin sheet 31 may be disposed in a portion of the second region RS110B.

[0067] In the present embodiment, the porous resin sheet contains polyolefin, but the present disclosure is not limited thereto. The porous resin sheet may or may not contain polyolefin. The porous resin sheet may contain a polymer of a monomer containing an ethylenically unsaturated group. Examples of monomers containing an ethylenically unsaturated group include tricyclodecane dimethanol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and the like.

[0068] In the present embodiment, the power storage unit is a rectangular parallelepiped object, but the present invention is not limited thereto. The power storage unit may be a cubic object. When the power storage unit is a cubic object, the electrode stack 10 may also be a cubic object.

[0069] In this embodiment, the length L5 of the negative electrode layer 112 in the Y-axis direction is longer than the length L6 of the positive electrode layer 111 in the Y-axis direction, but the present invention is not limited thereto. The length L5 may be the same as the length L6 or may be shorter than the length L6.

Claims

1. A power storage unit, characterized in that: have: An electrode stack including a plurality of bipolar electrodes stacked with a separator therebetween; a resin body forming a receiving space between adjacent bipolar electrodes among the plurality of bipolar electrodes; A non-aqueous electrolyte is contained in the containing space; A plurality of porous resin sheets, The bipolar electrode comprises: a current collector to which the resin body is fused at its periphery; a positive electrode layer formed on a first main surface of the current collector; and a negative electrode layer formed on a second main surface of the current collector opposite to the first main surface. The first main surface includes a first region that is not in contact with the positive electrode layer and the resin body. The second main surface includes a second region that is not in contact with the negative electrode layer and the resin body. The porous resin sheet includes at least one of a first porous resin sheet disposed in at least a portion of the first region and a second porous resin sheet disposed in at least a portion of the second region.

2. The power storage unit according to claim 1, characterized in that: The porous resin sheet includes one of the first porous resin sheet and the second porous resin sheet.

3. The power storage unit according to claim 1 or 2, characterized in that: The thickness of the first porous resin sheet is the same as the thickness of the positive electrode layer, and the thickness of the second porous resin sheet is the same as the thickness of the negative electrode layer.

4. The power storage unit according to claim 1 or 2, characterized in that: The first porous resin sheet is disposed over the entire first region, and the second porous resin sheet is disposed over the entire second region.

5. The power storage unit according to claim 1 or 2, characterized in that: The porous resin sheet contains polyolefin.

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