Energy 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 a storage cell.

Background Art

[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 surface of a current collector composed of a metal foil. The positive electrode layer and the negative electrode layer are arranged such 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, seals the edges of the current collector so as to surround the active material layer, and forms a storage space in which an electrolytic solution (hereinafter also referred to as a “non-aqueous electrolytic solution”) is stored. The reinforcing member reinforces an uncoated portion of the current collector where the active material layer is not located. When the current collector is viewed from the direction in which the active material layers of the positive electrode layer and the negative electrode layer face each other, the uncoated portion is provided between the spacer and the active material layer. The reinforcing member is arranged along the uncoated portion so as to straddle 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 facing direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] If air is present in the storage space, there is a risk that it is difficult for the non-aqueous electrolytic solution to enter the storage space. Therefore, the storage space may be decompressed before injecting the non-aqueous electrolytic solution into the storage cell.

[0005] The storage cell housing space disclosed in Patent Document 1 includes a space (hereinafter also referred to as the "uncoated portion space") between the uncoated portions of the current collectors in the positive and negative electrode layers and the separator, before the non-aqueous electrolyte is injected. Therefore, when the housing space is depressurized, the pressure difference between the pressure inside the housing space and atmospheric pressure may cause the current collectors to be pushed inward, potentially reducing the uncoated portion space. If the non-aqueous electrolyte is injected while the uncoated portion space is reduced, uneven distribution of the non-aqueous electrolyte volume within the housing space may occur. In areas with a relatively small amount of non-aqueous electrolyte, the non-aqueous electrolyte may be depleted during charging and discharging. If the non-aqueous electrolyte is depleted, the battery reaction may not proceed smoothly. As a result, the charging characteristics of the storage cell may deteriorate.

[0006] This disclosure has been made in light of the circumstances described above. One embodiment of this disclosure aims to solve the problem of providing an energy storage cell in which the distribution of the liquid volume of the non-aqueous electrolyte is more uniform. [Means for solving the problem]

[0007] The following embodiments are included as means to solve the above problems.

[0008] <1> A first aspect of the present disclosure is an energy storage cell comprising: an electrode stack including a plurality of bipolar electrodes stacked via a separator; a resin body forming a housing space between adjacent bipolar electrodes among the plurality of bipolar electrodes; a non-aqueous electrolyte housed in the housing space; and a plurality of porous resin sheets, wherein the bipolar electrodes have a current collector to which the resin body is welded around 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 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; and the porous resin sheets include 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.

[0009] In the first embodiment, the porous resin sheet comprises at least one of a first porous resin sheet and a second porous resin sheet. Therefore, in the state of the energy storage cell before the non-aqueous electrolyte is injected, the current collector is less likely to deform when the housing space is depressurized, due to the support of the porous resin sheet. As a result, the housing space is less likely to shrink than in the conventional design. Furthermore, the porous resin sheet easily retains the non-aqueous electrolyte inside. Consequently, the energy storage cell of the first embodiment has a more uniform distribution of the amount of non-aqueous electrolyte in the housing space than in the conventional design. Therefore, even if charging and discharging are repeatedly performed, localized depletion of the non-aqueous electrolyte in the housing space is less likely to occur. In other words, the charging characteristics of the energy storage cell of the first embodiment are easier to maintain than in the conventional design.

[0010] <2> A second aspect of the present disclosure is a storage cell in which the porous resin sheet has one of the first porous resin sheet and the second porous resin sheet. <1> This is the energy storage cell described in [reference].

[0011] When a storage cell is repeatedly charged and discharged, gas (hereinafter also referred to as "internal gas") may be generated within the containment space. In the second embodiment, internal gas tends to accumulate in the space within the containment space where one of the first porous resin sheet and the second porous resin sheet is not formed. In other words, internal gas is less likely to exist between the positive electrode layer and the negative electrode layer than in the configuration in which the porous resin sheet has both the first porous resin sheet and the second porous resin sheet. Therefore, lithium metal is less likely to be deposited on at least one of the positive electrode layer and the negative electrode layer. As a result, the storage cell of the second embodiment has a greater suppression of short circuits.

[0012] <3> A third aspect of the present disclosure is a storage cell in which 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. <1> or <2> This is the energy storage cell described in [reference].

[0013] In the third embodiment, when the storage cell is depressurized in the state before the non-aqueous electrolyte is injected, the current collector is more easily supported by the porous resin sheet and less prone to deformation. As a result, the storage cell of the third embodiment has a more uniform distribution of the liquid volume of the non-aqueous electrolyte within the storage space.

[0014] <4> A fourth aspect of the present disclosure is a storage cell in which the first porous resin sheet is arranged throughout the first region and the second porous resin sheet is arranged throughout the second region. <1> ~ <3> It is a storage cell described in one of the following documents.

[0015] In the fourth embodiment, when the storage cell is depressurized in the state before the non-aqueous electrolyte is injected, the current collector is more easily supported by the porous resin sheet and less prone to deformation. As a result, the storage cell of the fourth embodiment has a more uniform distribution of the liquid volume of the non-aqueous electrolyte within the storage space.

[0016] <5> A fifth aspect of the present disclosure is a storage cell in which the porous resin sheet comprises a polyolefin. <1> ~ <4> It is a storage cell described in one of the following documents.

[0017] Polyolefin is excellent in durability against non-aqueous electrolyte. The power storage cell of the fifth aspect can maintain charging characteristics over a long period rather than a configuration in which the porous resin sheet does not contain polyolefin.

Effect of the Invention

[0018] According to the present disclosure, a power storage cell with a more uniform distribution of the liquid volume of the non-aqueous electrolyte is provided.

Brief Description of the Drawings

[0019] [Figure 1] FIG. 1 is an external perspective view of a power storage cell according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1. [Figure 3] FIG. 3 is a partially enlarged view of FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view for explaining a method of manufacturing the power storage cell of the present disclosure. [Figure 5] FIG. 5 is a cross-sectional view of a power storage cell precursor according to an embodiment of the present disclosure in a state where the accommodation space is depressurized.

Modes for Carrying Out the Invention

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

[0021] Hereinafter, embodiments of the power storage cell of the present disclosure will be described with reference to the drawings. In the figures, the same or corresponding parts are denoted by the same reference numerals and the description will not be repeated.

[0022] (1) Power storage cell As shown in FIG. 1, the power storage cell 1 according to an embodiment of the present disclosure is a rectangular parallelepiped. The power storage cell 1 includes an electrode laminate 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 surface of the electrode laminate 10.

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

[0024] Each of the length L1 (see FIG. 1) in the X-axis direction and the length L2 (see FIG. 1) in the Y-axis direction of the power storage cell 1 may be more than 1 m.

[0025] (1.1) Electrode laminate The electrode stack 10 is a rectangular parallelepiped. The electrode stack 10 includes a plurality of bipolar electrodes 11 stacked via separators 12. Specifically, as shown in Figure 2, the electrode stack 10 has a plurality of bipolar electrodes 11, a plurality of separators 12, a positive electrode layer-side termination electrode 13, and a negative electrode layer-side termination electrode 14. The plurality of bipolar electrodes 11 and the plurality of separators 12 are stacked alternately along the axial direction. The positive electrode layer-side termination electrode 13 is stacked via separators 12 on the bipolar electrode 11 that is located furthest along one of the stacking directions (positive Z-axis direction). The negative electrode layer-side termination electrode 14 is stacked via separators 12 on the bipolar electrode 11 that is located furthest along the other of the stacking directions (negative Z-axis direction).

[0026] (1.1.1) Bipolar electrodes As shown in Figure 3, the bipolar electrode 11 includes a current collector 110, a positive electrode layer 111, and a negative electrode layer 112. The peripheral edge 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 have a known configuration.

[0027] The current collector 110 supplies current to the positive electrode layer 111 and the negative electrode layer 112 during the discharge or charging of the energy storage cell 1. Examples of materials for 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 known methods (e.g., plating, spray coating, etc.). The thickness of the current collector 110 may be 1 μm to 100 μm.

[0028] The positive electrode layer 111 contains a positive electrode active material (e.g., lithium composite metal oxide having a layered rock salt structure, metal oxide with a spinel structure, polyanionic compound, etc.) capable of adsorbing and releasing charge carriers. The positive electrode layer 111 may further contain, if necessary, a conductive additive (e.g., carbon nanofibers, etc.) to enhance electronic conductivity, a binder (e.g., polyvinylidene fluoride, etc.), an electrolyte support salt (lithium salt) to enhance ionic conductivity, a polymer electrolyte, and additives (e.g., trifluoropropylene carbonate, fillers as reinforcing materials, etc.). The thickness L3 of the positive electrode layer 111 (see Figure 3) may be 2 μm to 500 μm.

[0029] The negative electrode layer 112 contains a negative electrode layer active material (e.g., carbon (e.g., natural graphite, artificial graphite), a compound that can alloy with lithium (e.g., silicon, tin, etc.)) capable of intercalating and releasing charge carriers. The negative electrode layer 112 may further contain, if necessary, a conductive additive to enhance electronic conductivity (e.g., acetylene black), a binder (e.g., polyvinylidene fluoride, etc.), an electrolyte support salt (lithium salt) to enhance ionic conductivity, a polymer electrolyte, and additives (e.g., trifluoropropylene carbonate, fillers as reinforcing materials, etc.). The thickness L4 of the negative electrode layer 112 (see Figure 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 in the Y-axis direction of the negative electrode layer 112 (see Figure 3) is longer than the length L6 in the Y-axis direction of the positive electrode layer 111 (see Figure 3).

[0030] (1.1.2) Separator The separator 12 maintains the gap between the positive electrode layer 111 and the negative electrode layer 112 to prevent contact short circuits and allows charge carriers such as lithium ions to pass through. The periphery of the separator 12 is welded to the resin body 20. The separator 12 is held in place 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 also have a known configuration.

[0031] (1.1.3) Positive layer side termination electrode The positive electrode side terminal electrode 13 comprises 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 side terminal electrode 13 may have a known configuration.

[0032] (1.1.4) Termination electrode on the negative electrode layer side The negative electrode layer-side terminal electrode 14 comprises 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 configuration.

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

[0034] The resin body 20 is a rectangular tubular 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) for each of the current collector 110 and the separator 12. The resin body segments 21 are rectangular tubular objects with 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 held embedded in the resin body 20. Examples of materials for the resin body 20 include polyethylene, polystyrene, and acrylonitrile-butadiene-styrene copolymer synthetic resins (ABS resin, modified polypropylene, acrylonitrile styrene resin, etc.).

[0035] (1.3) Non-aqueous electrolyte The non-aqueous electrolyte is contained in the containment space T. The non-aqueous electrolyte may contain a non-aqueous solvent and a lithium salt. Examples of lithium salts include LiClO4, LiAsF6, LiPF6, LiBF4, LiCF3SO3, LiN(FSO2)2, and LiN(CF3SO2)2. Examples of non-aqueous solvents include cyclic carbonates, cyclic esters, linear carbonates, linear esters, and ethers. The non-aqueous electrolyte may also contain additives (e.g., lithium bis(oxalato)borate).

[0036] (1.4) Porous resin sheet The porous resin sheet 30 supports the current collector 110 and holds the non-aqueous electrolyte. The porous resin sheet 30 is a rectangular tubular object with a rectangular cross-section.

[0037] 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, as shown in Figure 3. 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 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 throughout the entire area of ​​the 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% to 50% by volume from the viewpoint of supporting the current collector 110 and retaining the non-aqueous electrolyte. Porosity indicates the percentage (by volume) of the void portion in the porous resin sheet 30. Specifically, the volume (cm³) of the porous resin sheet 30 3 It is calculated using the following formula (A) from the results obtained by measuring the ) and mass (g). Formula (A): Porosity (%) = (1 - mass / (density × volume)) × 100

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

[0041] (1.6) Manufacturing method A method for manufacturing an energy storage cell according to the embodiment of this disclosure comprises a preparation step, a lamination step, a welding step, a depressurization step, and a liquid injection step. The preparation step, lamination step, welding step, depressurization step, and liquid injection step are carried out in this order. This yields an energy storage cell 1.

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

[0043] The bipolar electrode sheet 91 includes a bipolar electrode 11 and a resin body segment 21 welded 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 welded to the periphery of the separator 12. The positive electrode layer side terminal electrode sheet 93 includes a positive electrode layer side terminal electrode 13 and a resin body segment 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 includes a negative electrode layer side terminal electrode 14 and a resin body segment 21 welded to the periphery of the current collector 110 of the negative electrode layer side terminal electrode 14. The preparation methods for each of the bipolar electrode sheet 91, separator sheet 92, positive electrode layer side terminal electrode sheet 93, negative electrode layer side terminal electrode sheet 94, and porous resin sheet 30 can be any known method.

[0044] (1.6.2) Lamination process In the lamination process, 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 laminated to obtain a laminate.

[0045] Specifically, as shown in Figure 4, first, a porous resin sheet 30 is placed on the negative electrode layer-side terminal electrode sheet 94. Then, the separator sheet 92, bipolar electrode sheet 91, and porous resin sheet 30 are repeatedly placed in this order. Finally, the positive electrode layer-side terminal electrode sheet 93 is placed on the separator sheet 92. Any known method of lamination is acceptable.

[0046] (1.6.3) Welding process In the welding process, the resin body segments 21 are heated and adjacent resin body segments 21 are welded together to obtain a storage cell precursor. By welding adjacent resin body segments 21 together, multiple resin body segments 21 are integrated to form a resin body 20. The configuration of the storage cell precursor is the same as that of the storage cell 1, except that it does not contain a non-aqueous electrolyte. Any known method can be used to heat the laminate.

[0047] (1.6.4) Depressurization process In the depressurization process, the pressure within the containment space T of the energy storage cell precursor is reduced. This causes the air in the containment space T to be expelled from the energy storage cell precursor. As a result, the non-aqueous electrolyte is more easily injected into the containment space T. Any known method can be used to reduce the pressure within the containment space T.

[0048] (1.6.5) Liquid injection process In the electrolyte injection step, a non-aqueous electrolyte is injected into the containment space T of the energy storage cell precursor. This yields the energy storage cell 1. Any known method can be used for injecting the non-aqueous electrolyte.

[0049] (1.7) Effects As described with reference to Figures 1 to 4, the energy storage cell 1 comprises an electrode laminate 10 including a plurality of bipolar electrodes 11 stacked via a separator 12, a resin body 20, a non-aqueous electrolyte, and a plurality of porous resin sheets 30. The bipolar electrodes 11 have a current collector 110, a positive electrode layer 111, and a negative electrode layer 112. The porous resin sheets 30 include a second porous resin sheet 31 located in the second region RS110B. As a result, when the storage space T in the energy storage cell precursor is depressurized, as shown in Figure 5, the first region RS110A of the current collector 110 on the positive electrode side terminal electrode 13 and the second region RS110B of the current collector 110 on the negative electrode side terminal electrode 14 are pushed inward towards the inside of the energy storage cell precursor due to the pressure difference between the pressure in the storage space T and atmospheric pressure. In this embodiment, the current collector 110 is less prone to deformation due to the support of the porous resin sheet 30. As a result, the storage space T is less likely to shrink than in the conventional design. Furthermore, the porous resin sheet 30 easily retains the non-aqueous electrolyte inside. As a result, the distribution of the liquid volume of the non-aqueous electrolyte in the storage space T of the energy storage cell 1 is more uniform than in the conventional design. Therefore, even if charging and discharging are repeatedly performed, local depletion of the non-aqueous electrolyte in the storage space T is less likely to occur. In other words, the charging characteristics of the energy storage cell 1 are easier to maintain than in the conventional design.

[0050] As explained with reference to Figures 1 to 4, the porous resin sheet 30 has only the second porous resin sheet 31. When the energy storage cell is repeatedly charged and discharged, internal gas may be generated within the containment space T. This internal gas tends to accumulate in the space P (see Figure 3) within the containment space T where the second porous resin sheet 31 is not formed. In other words, the porous resin sheet 30 is less likely to contain internal gas between the positive electrode layer 111 and the negative electrode layer 112 than in a configuration where the first porous resin sheet and the second porous resin sheet 31 are placed in space P. Therefore, lithium metal is less likely to be deposited on at least one of the positive electrode layer 111 and the negative electrode layer 112. As a result, the energy storage cell 1 has a greater suppression of short circuits.

[0051] As explained with reference to Figures 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, in the energy storage cell precursor, when the containment space T is depressurized, the current collector 110 is more easily supported by the porous resin sheet 30, and is less prone to deformation than in a configuration where the thickness L7 of the second porous resin sheet 31 is not the same as the thickness L4 of the negative electrode layer 112. Consequently, the energy storage cell 1 has a more uniform distribution of the liquid volume of the non-aqueous electrolyte in the containment space T.

[0052] As explained with reference to Figures 1 to 4, the second porous resin sheet 31 is arranged throughout the entire area of ​​the second region RS110B. As a result, in the energy storage cell precursor, when the containment space T is depressurized, the current collector 110 is more easily supported by the porous resin sheet 30 and is less prone to deformation than in a configuration where the second porous resin sheet 31 is not distributed across the entire second region RS110B. Consequently, the energy storage cell 1 has a more uniform distribution of the liquid volume of the non-aqueous electrolyte within the containment space T.

[0053] As explained with reference to Figures 1 to 4, the porous resin sheet 30 contains polyolefin. Polyolefins have excellent durability against non-aqueous electrolytes. The energy storage cell 1 can maintain its charging characteristics over a longer period of time compared to a configuration in which the porous resin sheet 30 does not contain polyolefin.

[0054] (2) Variant In this embodiment, the porous resin sheet 30 has only the second porous resin sheet 31, but the disclosure is not limited thereto. The porous resin sheet 30 may have, for example, a first porous resin sheet disposed in at least a portion 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 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 arranged throughout the entire second region RS110B, but the disclosure is not limited thereto. The second porous resin sheet 31 may be arranged in a portion of the second region RS110B.

[0057] In this embodiment, the porous resin sheet contains a polyolefin, but the disclosure is not limited thereto. The porous resin sheet may not contain a polyolefin. The porous resin sheet may also contain a polymer of monomers containing an ethylenically unsaturated group. Examples of monomers containing an ethylenically unsaturated group include tricyclodecanedimethanol di(meth)acrylate and trimethylolpropane tri(meth)acrylate.

[0058] In this embodiment, the energy storage cell is a rectangular parallelepiped, but the disclosure is not limited thereto. The energy storage cell may be a cubic shape. If the energy storage cell is a cubic shape, the electrode stack 10 may also be a cubic shape.

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

[0060] 1 Energy storage cell, 10 Electrode stack, 11 Bipolar electrode, 12 Separator, 13 Positive electrode side termination electrode, 14 Negative electrode side termination electrode, 20 Resin body, 21 Resin body segment, 30 Porous resin sheet, 31 Porous resin sheet, 91 Bipolar electrode sheet, 92 Separator sheet, 93 Positive electrode side termination electrode sheet, 94 Negative electrode side termination 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 Housing space

Claims

1. An electrode stack comprising multiple bipolar electrodes stacked via separators, A resin body that forms a housing space between adjacent bipolar electrodes among the plurality of bipolar electrodes, The non-aqueous electrolyte contained in the aforementioned containment space, Multiple porous resin sheets, Equipped with, The bipolar electrode comprises a current collector with 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. 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 comprises 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. The thickness of the first porous resin sheet is the same as the thickness of the positive electrode layer. A storage cell in which the thickness of the second porous resin sheet is the same as the thickness of the negative electrode layer.

2. The energy storage cell according to claim 1, wherein the porous resin sheet comprises either the first porous resin sheet or the second porous resin sheet.

3. The first porous resin sheet is arranged throughout the entire first region. The energy storage cell according to claim 1 or claim 2, wherein the second porous resin sheet is arranged over the entire area of ​​the second region.

4. The energy storage cell according to claim 1 or claim 2, wherein the porous resin sheet comprises a polyolefin.

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