Power storage cell

Abstract

To provide a power storage cell with uniformly distributed non-aqueous electrolyte liquid.SOLUTION: A disclosed power storage cell includes: an electrode laminate including multiple bipolar electrodes that are laminated via a separator; a resin body forming a storage space between adjacent bipolar electrodes in the multiple bipolar electrodes; non-aqueous electrolyte stored in the storage space; and a porous resin sheet. The bipolar electrode has a current collector with a resin body welded to the periphery, a positive electrode layer formed over a first main surface of the current collector; and a negative electrode layer formed over a second main surface at the opposite side of the first main surface of the current collector. The first main surface includes a first region that is in no contact with the positive electrode layer and the resin body. The second main surface includes a second region that is in no contact with the negative electrode layer and the resin body. The porous resin sheet has at least either one of a first porous resin sheet placed in at least a part of the first region and a second porous resin sheet placed in at least a part of the second region.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an energy storage cell. [Background technology]

[0002] Patent Document 1 discloses a storage cell. The storage cell includes a positive electrode layer, 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 metal foil. The positive electrode layer and the negative electrode layer are arranged so that the active material layers face each other. The separator is arranged between the positive electrode layer and the negative electrode layer and is interposed between the active material layers. The spacer is arranged between the positive electrode layer and the negative electrode layer, and seals the edge portion of the current collector so as to surround the active material layer, forming a storage space in which an electrolyte (hereinafter also referred to as a "non-aqueous electrolyte") is stored. The reinforcing member reinforces an uncoated portion of the current collector where the active material layer is not located. When viewed from the opposing direction of the active material layers in the positive electrode layer and the negative electrode layer, the current collector has the uncoated portion between the spacer and the active material layer. The reinforcing member is arranged along the uncoated portion so as to span the boundary between the active material layer and the uncoated portion and the boundary between the spacer and the uncoated portion when viewed from the opposing direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-069042 Summary of the Invention [Problem to be solved by the invention]

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

[0005] The storage space of the storage cell disclosed in Patent Document 1 includes a space (hereinafter also referred to as "uncoated partial space") between the separator and the uncoated parts of the current collectors of the positive electrode layer and the negative electrode layer before the nonaqueous electrolyte is injected. Therefore, when the storage space is decompressed, the current collectors may be pushed toward the inside of the storage cell due to the pressure difference between the pressure in the storage space and the atmospheric pressure, and the uncoated partial space may shrink. If the nonaqueous electrolyte is injected in a state in which the uncoated partial space is reduced, the distribution of the amount of the nonaqueous electrolyte in the storage space may become uneven. In a portion where the amount of the nonaqueous electrolyte is relatively small, the nonaqueous electrolyte may run out when charging and discharging are performed. If the nonaqueous electrolyte runs out, the battery reaction may not proceed easily. As a result, the charging characteristics of the storage cell may deteriorate.

[0006] The present disclosure has been made in consideration of the above circumstances. An object of one embodiment of the present disclosure is to provide a storage cell in which the distribution of the amount of non-aqueous electrolyte is more uniform. [Means for solving the problem]

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

[0008] <1> A first aspect of the present disclosure provides an energy storage cell comprising: an electrode stack including a plurality of bipolar electrodes stacked with separators interposed therebetween; a resin body forming a storage space between adjacent bipolar electrodes among the plurality of bipolar electrodes; a nonaqueous electrolyte solution contained in the storage space; and a plurality of porous resin sheets, wherein the bipolar electrodes have a current collector having the resin body welded to 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, wherein 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, and the porous resin sheet includes at least one of a first porous resin sheet arranged in at least a portion of the first region and a second porous resin sheet arranged in 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, when the storage space is depressurized in the state of the storage cell before the nonaqueous electrolyte is injected, the current collector is not easily deformed by the support of the porous resin sheet. As a result, the storage space is less likely to shrink than before. Furthermore, the porous resin sheet is more likely to hold the nonaqueous electrolyte therein. As a result, the storage cell of the first embodiment has a more uniform distribution of the amount of nonaqueous electrolyte in the storage space than before. Therefore, even if charging and discharging are repeated, local depletion of the nonaqueous electrolyte is less likely to occur in the storage space. In other words, the charging characteristics of the storage cell of the first embodiment are more easily maintained than before.

[0010] <2> In a second aspect of the present disclosure, there is provided a storage cell, wherein the porous resin sheet has one of the first porous resin sheet and the second porous resin sheet. <1> The storage cell according to the present invention is

[0011] When the charge and discharge of the storage cell is repeated, gas (hereinafter also referred to as "internal gas") may be generated in the storage space. In the second embodiment, the internal gas is likely to accumulate in the space of the storage space where one of the first and second porous resin sheets is not formed. In other words, the internal gas is less likely to exist between the positive electrode layer and the negative electrode layer than in a configuration in which the porous resin sheet has the first and second porous resin sheets. Therefore, lithium metal is less likely to deposit on at least one of the positive electrode layer and the negative electrode layer. As a result, the occurrence of a short circuit is further suppressed in the storage cell of the second embodiment.

[0012] <3> In a third aspect of the present disclosure, there is provided a storage cell, wherein a thickness of the first porous resin sheet is the same as a thickness of the positive electrode layer, and a thickness of the second porous resin sheet is the same as a thickness of the negative electrode layer. <1> or <2> The storage cell according to the present invention is

[0013] In the third embodiment, when the storage space is depressurized in the state of the storage cell before the nonaqueous electrolyte is injected, the current collector is more likely to be supported by the porous resin sheet and is less likely to deform, and as a result, the distribution of the amount of nonaqueous electrolyte in the storage space is more uniform in the storage cell of the third embodiment.

[0014] <4> In a fourth aspect of the present disclosure, there is provided a storage cell, wherein 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. <1> ~ <3> The present invention relates to a storage cell.

[0015] In the fourth embodiment, when the storage space is depressurized in the state of the storage cell before the nonaqueous electrolyte is injected, the current collector is more likely to be supported by the porous resin sheet and is less likely to deform, and as a result, the distribution of the amount of nonaqueous electrolyte in the storage space is more uniform in the storage cell of the fourth embodiment.

[0016] <5> In a fifth aspect of the present disclosure, there is provided a storage cell, wherein the porous resin sheet contains polyolefin. <1> ~ <4> The present invention relates to a storage cell.

[0017] Polyolefin has excellent durability against non-aqueous electrolyte solutions, and the electricity storage cell according to the fifth embodiment can maintain the charging characteristics for a longer period of time than a configuration in which the porous resin sheet does not contain polyolefin. Effect of the Invention

[0018] According to the present disclosure, a storage cell is provided in which the distribution of the amount of non-aqueous electrolyte is more uniform. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is an external perspective view of an electricity storage cell according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 3 is a partially enlarged view of FIG. [Figure 4] FIG. 4 is a cross-sectional view for explaining the method for manufacturing the energy storage cell according to the present disclosure. [Diagram 5] FIG. 5 is a cross-sectional view of a power storage cell precursor according to an embodiment of the present disclosure with the accommodation space depressurized. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] In the present disclosure, a numerical range indicated using "~" means a range including the numerical values ​​described before and after "~" as the minimum and maximum values, respectively. In the numerical ranges described in stages in the present disclosure, the upper limit or lower limit described in a certain numerical range may be replaced with the upper limit or lower limit of another numerical range described in stages. In the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment. In the present disclosure, the term "process" includes not only an independent process, but also a process that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved.

[0021] Hereinafter, an embodiment of the storage cell battery of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and description thereof will not be repeated.

[0022] (1) Energy storage cell The energy storage cell 1 according to the embodiment of the present disclosure is a rectangular parallelepiped object, as shown in Fig. 1. The energy storage cell 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. 2). The resin body 20 covers the side surfaces of the electrode stack 10.

[0023] In the embodiment, one side in the longitudinal direction of the main surface of the storage cell 1 is defined as the X-axis positive direction, and the opposite side is defined as the X-axis negative direction. One side in the lateral direction of the main surface of the storage cell 1 is defined as the Y-axis positive direction, and the opposite side is defined as the X-axis negative direction. One side in the thickness direction of the storage cell 1 is defined as the Z-axis positive direction, and the opposite side is defined as the Z-axis negative direction. The X-axis, Y-axis, and Z-axis are mutually orthogonal. The Z-axis negative direction and the direction of gravity are parallel. Note that these orientations do not limit the orientations of the storage cell of the present disclosure during use.

[0024] The length L1 in the X-axis direction (see FIG. 1) and the length L2 in the Y-axis direction (see FIG. 1) of the energy storage cell 1 may each be greater than 1 m.

[0025] (1.1) Electrode laminate The electrode laminate 10 is a rectangular parallelepiped. The electrode laminate 10 includes a plurality of bipolar electrodes 11 stacked with a separator 12 interposed therebetween. More specifically, as shown in FIG. 2, the electrode laminate 10 has a plurality of bipolar electrodes 11, a plurality of separators 12, a positive electrode layer side end electrode 13, and a negative electrode layer side end electrode 14. The plurality of bipolar electrodes 11 and the plurality of separators 12 are alternately stacked along the axial direction. The positive electrode layer side end electrode 13 is stacked with the separator 12 interposed 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. The negative electrode layer side end electrode 14 is stacked with the separator 12 interposed 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.

[0026] (1.1.1) Bipolar electrodes 3, the bipolar electrode 11 has 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 a first main surface S110A of the current collector 110. The negative electrode layer 112 is formed on a second main surface S110B of the current collector 110. The bipolar electrode 11 may have a known configuration.

[0027] The current collector 110 supplies a current to the positive electrode layer 111 and the negative electrode layer 112 during discharging or charging of the power storage cell 1. Examples of the current collector 110 include aluminum foil, copper foil, nickel foil, titanium foil, and stainless steel foil. A coating layer may be formed on the surface of the current collector 110 by a known method (for example, plating, spray coating, etc.). The thickness of the current collector 110 may be 1 μm to 100 μm.

[0028] The positive electrode layer 111 includes a positive electrode layer active material (e.g., a lithium composite metal oxide having a layered rock salt structure, a metal oxide having a spinel structure, a polyanion-based compound, etc.) capable of absorbing and releasing charge carriers. The positive electrode layer 111 may further include a conductive assistant (e.g., carbon nanofiber, etc.) for increasing electronic conductivity, a binder (e.g., polyvinylidene fluoride, etc.), an electrolyte supporting salt (lithium salt) for increasing ionic conductivity, a polymer electrolyte, and an additive (e.g., trifluoropropylene carbonate, a filler as a reinforcing material, etc.) as necessary. The thickness L3 (see FIG. 3) of the positive electrode layer 111 may be 2 μm to 500 μm.

[0029] The negative electrode layer 112 includes a negative electrode layer active material capable of absorbing and releasing charge carriers (e.g., carbon (e.g., natural graphite, artificial graphite), a compound capable of alloying with lithium (e.g., silicon, tin, etc.), etc.). The negative electrode layer 112 may further include a conductive assistant (e.g., acetylene black, etc.) for enhancing electronic conductivity, a binder (e.g., polyvinylidene fluoride, etc.), an electrolyte supporting salt (lithium salt) for enhancing ionic conductivity, a polymer electrolyte, and an additive (e.g., trifluoropropylene carbonate, a filler as a reinforcing material, etc.) as necessary. The thickness L4 of the negative electrode layer 112 (see FIG. 3) may be 2 μm to 500 μm. The thickness L4 of the negative electrode layer 112 may 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 FIG. 3) is longer than the length L6 of the positive electrode layer 111 in the Y-axis direction (see FIG. 3).

[0030] (1.1.2) Separator The separator 12 maintains a distance between the positive electrode layer 111 and the negative electrode layer 112 to prevent contact short circuit, and allows charge carriers such as lithium ions (e.g., lithium ions) to pass through. The periphery of the separator 12 is welded to the resin body 20. The separator 12 is held by the resin body 20. Examples of the separator 12 include a porous resin sheet or a nonwoven fabric. Examples of materials for the porous resin sheet include polyolefins (polypropylene, polyethylene, etc.). Examples of materials for the nonwoven fabric include polypropylene, polyethylene terephthalate, methylcellulose, etc. The separator 12 may have a known configuration.

[0031] (1.1.3) Positive electrode layer side termination electrode The positive electrode layer side termination electrode 13 has a current collector 110 and a positive electrode layer 111. The positive electrode layer 111 is formed on a second main surface S110B of the current collector 110. The positive electrode layer side termination electrode 13 may have a known configuration.

[0032] (1.1.4) Termination electrode on the negative electrode layer side The negative electrode layer side termination electrode 14 has a current collector 110 and a negative electrode layer 112. The negative electrode layer 112 is formed on a first main surface S110A of the current collector 110. The negative electrode layer side termination electrode 14 may have a known configuration.

[0033] (1.2) Resin body The resin body 20 forms a storage space T between adjacent bipolar electrodes 11 among the plurality of bipolar electrodes 11. In the storage space T, the positive electrode layer 111, the negative electrode layer 112, the separator 12, and the porous resin sheet 30 are stored in a state of being contained in a non-aqueous electrolyte. In this embodiment, the resin body 20 prevents the electrolyte stored in the storage space T from leaking to the outside. The resin body 20 can prevent moisture from entering the storage space T from the outside of the energy 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, discharging, etc. from leaking to the outside of the energy storage cell 1.

[0034] The resin body 20 is a square tubular object having a rectangular cross section. The resin body has a plurality of resin body segments 21 that hold the peripheries of the current collector 110 and the separator 12. The resin body segments 21 are arranged for each of the current collector 110 and the separator 12 along the stacking direction (Z-axis direction). The resin body segments 21 are square tubular objects having a rectangular cross section. The resin body segments 21 are welded to the periphery of the current collector 110. In the stacking direction, adjacent resin body segments 21 are welded to each other. Therefore, the periphery of the current collector 110 and the periphery of the separator 12 are each held in a state of being embedded in the resin body 20. Examples of materials for the resin body 20 include polyethylene, polystyrene, acrylonitrile-butadiene-styrene copolymer synthetic resin (ABS resin, modified polypropylene, acrylonitrile styrene resin, etc.

[0035] (1.3) Non-aqueous electrolyte The nonaqueous electrolyte is accommodated in the accommodation space T. The nonaqueous electrolyte may include a nonaqueous solvent and a lithium salt. Examples of the lithium salt include LiClO4, LiAsF6, LiPF6, LiBF4, LiCF3SO3, LiN(FSO2)2, and LiN(CF3SO2)2. Examples of the nonaqueous solvent include cyclic carbonates, cyclic esters, chain carbonates, chain esters, and ethers. The nonaqueous electrolyte may include an additive (e.g., lithium bis(oxalato)borate, etc.).

[0036] (1.4) Porous resin sheet The porous resin sheet 30 supports the current collector 110 and holds the non-aqueous electrolyte solution. The porous resin sheet 30 is in the form of a square tube having a rectangular cross section.

[0037] 3, 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 sheets 31 arranged in the second region RS110B.

[0038] In this embodiment, the thickness L7 (see FIG. 3) of the second porous resin sheet 31 is the same as the thickness L4 of the negative electrode layer 112. The thickness L7 (see FIG. 3) of the second porous resin sheet 31 may be 2 μm to 500 μm. The second porous resin sheet 31 is disposed over the entire second region RS110B. The material of the porous resin sheet 30 is, for example, polyolefin (polypropylene, polyethylene, etc.).

[0039] The porosity of the porous resin sheet 30 is not particularly limited, but is preferably 30% by volume to 50% by volume from the viewpoints of supporting the current collector 110 and retaining the non-aqueous electrolyte. The porosity indicates the ratio (volume %) of the pores in the porous resin sheet 30. Specifically, when the volume (cm 3 ) and mass (g) are measured and calculated using the following formula (A). Formula (A): Porosity (%) = (1-mass / (density x volume)) x 100

[0040] (1.5) Application The power storage cell 1 can be used as a power source for, for example, electric four-wheel vehicles, electric two-wheel vehicles, portable devices, power storage systems, and the like. Examples of electric four-wheel vehicles include battery electric vehicles (BEVs), plug-in hybrid electric vehicles (PHEVs), and hybrid electric vehicles (HEVs). Examples of electric two-wheel vehicles include electric motorcycles and electrically assisted bicycles. Examples of portable devices include smartphones, tablet computers, notebook computers, power tools, and video cameras. Examples of power storage systems include home power storage systems, industrial power storage systems, and energy storage systems (ESSs).

[0041] (1.6) Manufacturing method The method for producing a storage cell according to an embodiment of the present disclosure includes a preparation step, a stacking step, a welding step, a depressurization step, and a liquid injection step. The preparation step, stacking step, welding step, depressurization step, and liquid injection step are performed in this order. As a result, the storage cell 1 is obtained.

[0042] (1.6.1) Preparation process In the preparation step, a bipolar electrode sheet 91, a separator sheet 92, a positive electrode layer side terminal electrode sheet 93, a negative electrode layer side terminal electrode sheet 94, and a porous resin sheet 30 are prepared.

[0043] The bipolar electrode sheet 91 has a bipolar electrode 11 and a resin body divided body 21 welded to the periphery of the current collector 110 of the bipolar electrode 11. The separator sheet 92 has a separator 12 and a resin body divided body 21 welded to the periphery of the separator 12. The positive electrode layer side terminal electrode sheet 93 has a positive electrode layer side terminal electrode 13 and a resin body divided body 21 welded to the periphery of the current collector 110 of the positive electrode layer side terminal electrode 13. The negative electrode layer side terminal electrode sheet 94 has a negative electrode layer side terminal electrode 14 and a resin body divided body 21 welded to the periphery of the current collector 110 of the negative electrode layer side terminal electrode 14. The bipolar electrode sheet 91, the separator sheet 92, the positive electrode layer side terminal electrode sheet 93, the negative electrode layer side terminal electrode sheet 94, and the porous resin sheet 30 may be prepared by any known method.

[0044] (1.6.2) Lamination process In the lamination step, the bipolar electrode sheet 91, the separator sheet 92, the positive electrode layer side terminal electrode sheet 93, the negative electrode layer side terminal electrode sheet 94, and the porous resin sheet 30 are laminated to obtain a laminate.

[0045] Specifically, as shown in Fig. 4, first, a porous resin sheet 30 is placed on a negative electrode layer side terminal electrode sheet 94. Next, a stacking operation is repeatedly performed in which a separator sheet 92, a bipolar electrode sheet 91, and a porous resin sheet 30 are placed in this order. Finally, a positive electrode layer side terminal electrode sheet 93 is placed on the separator sheet 92. The stacking method may be a known method.

[0046] (1.6.3) Welding process In the welding step, the resin body segments 21 are heated to weld adjacent resin body segments 21 together to obtain a storage cell precursor. By welding adjacent resin body segments 21 together, the multiple resin body segments 21 are integrated to form the resin body 20. The storage cell precursor has the same configuration as the storage cell 1, except that it does not include a non-aqueous electrolyte. The method for heating the laminate may be a known method.

[0047] (1.6.4) Decompression step In the depressurization step, the pressure in the storage space T of the energy storage cell precursor is reduced. This causes the air in the storage space T to be discharged to the outside of the energy storage cell precursor. As a result, the nonaqueous electrolyte is easily injected into the storage space T. The method for reducing the pressure in the storage space T may be any known method.

[0048] (1.6.5) Liquid injection process In the liquid injection step, a non-aqueous electrolyte is injected into the accommodation space T of the electricity storage cell precursor. This results in the electricity storage cell 1. The method for injecting the non-aqueous electrolyte may be a known method.

[0049] (1.7) Effects 1 to 4, the energy storage cell 1 includes an electrode laminate 10 including a plurality of bipolar electrodes 11 laminated with separators 12 interposed therebetween, a resin body 20, a non-aqueous electrolyte, and a plurality of porous resin sheets 30. The bipolar electrodes 11 include 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 a second region RS110B. As a result, when the storage space T is decompressed in the storage cell precursor, as shown in FIG. 5, due to the pressure difference between the pressure in the storage space T and atmospheric pressure, the first region RS110A of the current collector 110 of the positive electrode layer side termination electrode 13 and the second region RS110B of the current collector 110 of the negative electrode layer side termination electrode 14 are pushed toward the inside of the storage cell precursor. In this embodiment, the current collector 110 is not easily deformed due to the support of the porous resin sheet 30. As a result, the storage space T is less likely to shrink than before. Furthermore, the porous resin sheet 30 is more likely to hold the nonaqueous electrolyte therein. As a result, the storage cell 1 has a more uniform distribution of the amount of nonaqueous electrolyte in the storage space T than before. Therefore, even if charging and discharging are repeatedly performed, local depletion of the nonaqueous electrolyte is less likely to occur in the storage space T. In other words, the charging characteristics of the storage cell 1 are more easily maintained than before.

[0050] As described with reference to FIGS. 1 to 4, the porous resin sheet 30 has only the second porous resin sheet 31. 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 a space P (see FIG. 3) of the storage space T where the second porous resin sheet 31 is not formed. In other words, the internal gas is less likely to exist between the positive electrode layer 111 and the negative electrode layer 112 than in a configuration in which the porous resin sheet 30 has a first porous resin sheet and a second porous resin sheet 31 arranged in the space P. Therefore, lithium metal is less likely to deposit on at least one of the positive electrode layer 111 and the negative electrode layer 112. As a result, the occurrence of a short circuit in the storage cell 1 is further suppressed.

[0051] As described with reference to FIGS. 1 to 4, the thickness L7 of the second porous resin sheet 31 is the same as the thickness L4 of the negative electrode layer 112. As a result, when the storage space T is depressurized in the energy storage cell precursor, the current collector 110 is more likely to be supported by the porous resin sheet 30 and is less likely to deform than in 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 energy storage cell 1 has a more uniform distribution of the amount of nonaqueous electrolyte in the storage space T.

[0052] As described with reference to FIGS. 1 to 4, the second porous resin sheet 31 is disposed over the entire second region RS110B. As a result, when the storage space T is depressurized in the energy storage cell precursor, the current collector 110 is more likely to be supported by the porous resin sheet 30 and is less likely to deform than in a configuration in which the second porous resin sheet 31 is not disposed over the entire second region RS110B. As a result, the energy storage cell 1 has a more uniform distribution of the amount of nonaqueous electrolyte in the storage space T.

[0053] As described with reference to FIGS. 1 to 4, the porous resin sheet 30 contains polyolefin. Polyolefin has excellent durability against non-aqueous electrolyte solutions, and the energy storage cell 1 can maintain the charging characteristics for a longer period of time than a configuration in which the porous resin sheet 30 does not contain polyolefin.

[0054] (2) Variations In this embodiment, the porous resin sheet 30 has only the second porous resin sheet 31, but the present disclosure is not limited thereto. The porous resin sheet 30 may have, for example, a first porous resin sheet disposed in at least a part of the first region RS110A, and the second porous resin sheet 31. The porous resin sheet 30 may have, for example, only the first porous resin sheet.

[0055] In this 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 disclosure is not limited thereto. The thickness T7 of the second porous resin sheet 31 does not have to be the same as the thickness T4 of the negative electrode layer 112.

[0056] In this embodiment, the second porous resin sheet 31 is disposed over the entire second region RS110B, but the present disclosure is not limited thereto. The second porous resin sheet 31 may be disposed in a part of the second region RS110B.

[0057] In this embodiment, the porous resin sheet includes polyolefin, but the present disclosure is not limited thereto. The porous resin sheet may or may not include polyolefin. The porous resin sheet may include a polymer of a monomer containing an ethylenically unsaturated group. Examples of the monomer containing an ethylenically unsaturated group include tricyclodecane dimethanol di(meth)acrylate and trimethylolpropane tri(meth)acrylate.

[0058] In this embodiment, the storage cell is a rectangular parallelepiped, but the present disclosure is not limited thereto. The storage cell may be a cube. When the storage cell is a cube, the electrode stack 10 may also be a cube.

[0059] 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 disclosure is not limited to this. The length L5 may be the same as the length L6, or may be shorter than the length L6. [Explanation of symbols]

[0060] 1 storage cell, 10 electrode laminate, 11 bipolar electrode, 12 separator, 13 positive electrode layer side end electrode, 14 negative electrode layer side end electrode, 20 resin body, 21 resin body division, 30 porous resin sheet, 31 porous resin sheet, 91 bipolar electrode sheet, 92 separator sheet, 93 positive electrode layer side end electrode sheet, 94 negative electrode layer side end electrode sheet, 110 current collector, 111 positive electrode layer, 112 negative electrode layer, RS110A first region, RS110B second region, S110A first main surface, S110B second main surface, T storage space

Claims

1. an electrode stack including a plurality of bipolar electrodes stacked with separators interposed therebetween; a resin body that forms a storage space between adjacent bipolar electrodes among the plurality of bipolar electrodes; A nonaqueous electrolyte solution contained in the containing space; A plurality of porous resin sheets; Equipped with the bipolar electrode includes a current collector having the resin body welded to a 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 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 has at least one of a first porous resin sheet arranged in at least a portion of the first region and a second porous resin sheet arranged in at least a portion of the second region.

2. The energy storage cell according to claim 1 , wherein the porous resin sheet has one of the first porous resin sheet and the second porous resin sheet.

3. The thickness of the first porous resin sheet is the same as the thickness of the positive electrode layer, The energy storage cell according to claim 1 or 2, wherein a thickness of the second porous resin sheet is the same as a thickness of the negative electrode layer.

4. The first porous resin sheet is disposed over the entire first region, The energy storage cell according to claim 1 , wherein the second porous resin sheet is disposed over the entire second region.

5. The storage cell according to claim 1 or 2, wherein the porous resin sheet contains a polyolefin.

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