Manufacturing method for electrode stack modules

Abstract

This disclosure aims to suppress deformation of the internal space during the depressurization process before liquid injection, thereby preventing liquid injection defects. [Solution] The present disclosure's method for manufacturing an electrode stack module comprises an electrode stack module 100 having an electrode stack 200, a sealing sheet 300, a sealing member 310, and an internal space 110, wherein the sealing member 310 has an injection port 350 that connects the internal space 110 to the outside, and the internal space 110 has an electrode stack holding portion 110b and an electrode stack non-holding portion 110a, and the method includes: setting an external space forming jig 400 on the sealing sheet 300 which forms a part of the electrode stack non-holding portion 110a to form an external space 410 outside the electrode stack module 100; reducing the pressure of the internal space 110 and the external space 410; and releasing the pressure in the external space 410 while injecting an electrolyte into the internal space 110 through the injection port 350 to release the pressure in the internal space 110.

Description

[Technical Field]

[0001] This disclosure relates to a method for manufacturing an electrode stack module. [Background technology]

[0002] An electrode stack module is a battery in which an electrode stack having, for example, a positive electrode current collector layer, a positive electrode active material layer, an electrolyte layer, a negative electrode active material layer, and a negative electrode current collector layer in that order is housed in an outer casing or the like.

[0003] The manufacturing process for electrode stack modules sometimes includes a step of injecting an electrolyte solution into the module. Whether or not the electrolyte solution sufficiently reaches the active material layer of the electrode stack significantly affects the performance of the electrode stack module. Therefore, various studies have been conducted on the electrolyte injection process.

[0004] For example, Patent Document 1 discloses a method for manufacturing an energy storage module in which a plurality of bipolar electrodes, each having an electrode portion coated with an active material on both sides of the electrode plate and an uncoated portion where the active material is not coated, are stacked with a separator in between so that the uncoated portions overlap, and an electrolyte is injected between the bipolar electrodes, comprising a pressurization step of reducing the size of the internal space between the bipolar electrodes by applying pressure to each of the uncoated portions, and an injection step of injecting the electrolyte between the bipolar electrodes in the state in which the size of the internal space has been reduced by the pressurization step.According to the method described in Patent Document 1, it is possible to prevent the occurrence of unimpregnated portions in the manufacture of an energy storage module having an internal space due to the uncoated portion.

[0005] Furthermore, Patent Document 2 describes a plurality of bipolar electrodes stacked on top of each other, an outermost positive electrode positioned on one of the outermost bipolar electrodes in the stacking direction of the plurality of bipolar electrodes, an outermost negative electrode positioned on the other outermost bipolar electrode in the stacking direction of the plurality of bipolar electrodes, a first sealing portion that seals the first outer region formed between the outermost positive electrode and the bipolar electrode facing the outermost positive electrode among the plurality of bipolar electrodes when the pressure of the first outer region is lower than atmospheric pressure, and among the outermost negative electrode and the plurality of bipolar electrodes A second sealing portion that seals the second outer region formed between the outermost negative electrode and the bipolar electrode facing it when the pressure of the second outer region is lower than atmospheric pressure; an inner sealing portion that seals the inner region formed between a pair of bipolar electrodes adjacent to each other in the stacking direction when the pressure of the inner region is lower than atmospheric pressure; a first insulating member that insulates the outermost positive electrode from the bipolar electrode among the plurality of bipolar electrodes that faces the outermost positive electrode; and the outermost negative electrode from the bipolar electrode among the plurality of bipolar electrodes that faces the outermost negative electrode. The bipolar electrode comprises a second insulating member that insulates from the aor electrode, and an inner insulating member that insulates between a pair of bipolar electrodes adjacent to each other in the stacking direction, and each of the plurality of bipolar electrodes has a current collector including a positive electrode current collector foil and a negative electrode current collector foil, a positive electrode active material layer provided on the positive electrode current collector foil in the current collector, and a negative electrode active material layer provided on the negative electrode current collector foil in the current collector, the outermost positive electrode has a positive electrode current collector foil and a positive electrode active material layer provided on the positive electrode current collector foil, and the outermost negative electrode has a negative electrode current collector foil and a negative electrode active material layer provided on the negative electrode current collector foil Furthermore, an uncoated positive electrode portion is formed on the peripheral edge of the positive electrode current collector foil in each current collector and on the peripheral edge of the positive electrode current collector foil in the outermost positive electrode, where the positive electrode active material layer is not provided; an uncoated negative electrode portion is formed on the peripheral edge of the negative electrode current collector foil in each current collector and on the peripheral edge of the negative electrode current collector foil in the outermost negative electrode, facing the uncoated positive electrode portion in the lamination direction and where the negative electrode active material layer is not provided; and the region between the uncoated positive electrode portion in the outermost positive electrode and the uncoated negative electrode portion facing the uncoated positive electrode portion constitutes the first outer region.A storage module is disclosed in which the region between the uncoated negative electrode portion and the uncoated positive electrode portion facing the uncoated negative electrode portion of the outermost negative electrode constitutes the second outer region, the region between the uncoated positive electrode portion and the uncoated negative electrode portion of a pair of adjacent bipolar electrodes facing each other in the stacking direction constitutes the inner region, the first insulating member includes a first outer insulating portion disposed in the first outer region, the second insulating member includes a second outer insulating portion disposed in the second outer region, and the inner insulating member includes an inner insulating portion disposed in the inner region, and the thickness of the first outer insulating portion and the second outer insulating portion are greater than the thickness of the inner insulating portion. According to the storage module described in Patent Document 2, it is possible to suppress a decrease in energy density and damage to the sealing portion while suppressing a short circuit when the internal pressure is reduced to a level lower than atmospheric pressure.

[0006] Furthermore, Patent Document 3 describes a method for manufacturing a bipolar energy storage device comprising: an electrode laminate comprising a current collector, a positive electrode active material layer provided on one side of the current collector, and a negative electrode active material layer provided on the other side of the current collector, a sealing body that forms an internal space for containing electrolyte between adjacent current collectors and seals the internal space, and a liquid injection port formed in the sealing body that communicates the internal space with the outside, the method comprising: a first depressurization step of reducing the internal space to a first pressure lower than atmospheric pressure through an attachment attached to the liquid injection port; and after the first depressurization step, the internal pressure of a holding part that holds a predetermined amount of electrolyte is increased to a pressure higher than the first pressure, and the electrolyte is dispensed from the holding part through the liquid injection port. A method for manufacturing a bipolar energy storage device is disclosed, comprising: a first liquid injection step of injecting a predetermined amount of electrolyte into the internal space that has been depressurized in a first depressurization step; a second depressurization step, after the first liquid injection step, of depressurizing the internal space into which the predetermined amount of electrolyte has been injected to a second pressure lower than atmospheric pressure through the holding part and the liquid injection port, thereby causing a portion of the electrolyte to flow back from the internal space to the holding part; and a second liquid injection step, after the second depressurization step, of raising the pressure inside the holding part that holds the electrolyte that has flowed back in the second depressurization step to a pressure higher than the second pressure, and injecting the electrolyte into the internal space through the liquid injection port from the holding part, wherein the second depressurization step includes an initial depressurization step of depressurizing the internal space at a lower depressurization rate than the first depressurization step. According to the method described in Patent Document 3, it is possible to suppress poor electrolyte impregnation of electrodes. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2019-200954 [Patent Document 2] Japanese Patent Publication No. 2024-055180 [Patent Document 3] Japanese Patent Publication No. 2022-188536 [Overview of the project] [Problems that the invention aims to solve]

[0008] For example, when using the method described in Patent Document 3, in which the internal space into which the electrolyte is injected is subjected to low pressure and then returned to atmospheric pressure while the electrolyte is injected, it is conceivable that the internal space may deform when the pressure is reduced. If the internal space deforms in this way, especially if the area near the injection port of the internal space deforms, the injection path may be obstructed, which could result in insufficient injection of the electrolyte and lead to injection failure.

[0009] Therefore, the present disclosure aims to suppress deformation of the internal space during the depressurization process before liquid injection, thereby preventing liquid injection defects. [Means for solving the problem]

[0010] This disclosure aims to achieve the above objectives by the following means:

[0011] (Aspect 1) A method for manufacturing an electrode stack module, The above electrode stack module, Electrode stack, A sealing sheet that seals the upper and lower surfaces of the electrode stack described above, A sealing member for sealing the side surface of the electrode stack, and The internal space formed by the above sealing sheet and the above sealing member, It has, The sealing member has a liquid injection port that connects the internal space to the outside, The above internal space, when viewed in the planar direction, has an electrode stack holding portion that holds the electrode stack and an electrode stack non-holding portion that does not hold the electrode stack. The non-holding portion of the electrode stack is a space surrounded by the electrode stack, the sealing sheet, and the sealing member, and is formed on the outer periphery in the planar direction of the electrode stack module. The above method, Install an external space forming jig on the sealing sheet that forms a part of the non-retaining portion of the electrode laminate to form an external space outside the electrode laminate module, where the part of the non-retaining portion of the electrode laminate faces the liquid injection port. Reduce the pressure in the internal space and the external space, and While releasing the pressure reduction in the external space, inject an electrolytic solution into the internal space through the liquid injection port to release the pressure reduction in the internal space. including A method for manufacturing an electrode laminate module. (Aspect 2) The method according to aspect 1, wherein the difference between the pressure in the internal space and the pressure in the external space after the pressure reduction is 10 kPa or less. (Aspect 3) The method according to aspect 1 or 2, wherein the area of the electrode laminate module in the plane direction is 200 cm 2 or more.

Advantages of the Invention

[0012] According to the method of the present disclosure, an external space forming jig is installed on the sealing sheet that forms a part of the non-retaining portion of the electrode laminate to form an external space outside the electrode laminate module, and then the internal space and the external space are depressurized. As a result, deformation of the sealing sheet due to the pressure difference between the internal space and the outside of the electrode laminate module can be suppressed.

[0013] In this way, by suppressing the deformation of the sealing sheet during pressure reduction, a flow path for the electrolytic solution or the like can be ensured during liquid injection, thereby suppressing the occurrence of poor liquid injection of the electrolytic solution.

Brief Description of the Drawings

[0014] [Figure 1] FIG. 1 is a schematic diagram for explaining the method of the present disclosure. [Figure 2] FIG. 2 is a schematic diagram for explaining the method of the present disclosure. [Figure 3] FIG. 3 is a schematic diagram for explaining the method of the present disclosure. [Modes for carrying out the invention]

[0015] ≪Manufacturing Method for Electrode Stack Modules≫ The method for manufacturing an electrode stack module according to this disclosure is A method for manufacturing an electrode stack module, The above electrode stack module, Electrode stack, A sealing sheet that seals the upper and lower surfaces of the electrode stack described above, A sealing member for sealing the side surface of the electrode stack, and The internal space formed by the above sealing sheet and the above sealing member, It has, The sealing member has a liquid injection port that connects the internal space to the outside, The above internal space, when viewed in the planar direction, has an electrode stack holding portion that holds the electrode stack and an electrode stack non-holding portion that does not hold the electrode stack. The non-holding portion of the electrode stack is a space surrounded by the electrode stack, the sealing sheet, and the sealing member, and is formed on the outer periphery in the planar direction of the electrode stack module. The above method, An external space forming jig is placed on the sealing sheet that forms a part of the non-holding portion of the electrode stack to form an external space outside the electrode stack module, where the part of the non-holding portion of the electrode stack faces the liquid injection port. Depressurizing the above internal space and the above external space, While releasing the pressure in the external space, the electrolyte is injected into the internal space through the injection port to release the pressure in the internal space. Includes.

[0016] According to the method described above, deformation of the internal space during the depressurization process before liquid injection can be suppressed, thereby preventing liquid injection defects.

[0017] Conventional methods for manufacturing electrode stack modules utilize a pressure difference during the injection process. Specifically, the internal space of the electrode stack module is depressurized, and then a tube supplying the electrolyte is connected to the injection port of the electrode stack module. The depressurization of the internal space is then released, allowing the internal space to be replaced by the electrolyte, thus injecting the electrolyte. In this case, when the internal space is depressurized, the outer container forming the electrode stack module deforms due to the pressure difference between the internal pressure of the electrode stack module and the external pressure of the electrode stack module.

[0018] In contrast, according to the method of this disclosure, an external space forming jig is placed on the sealing sheet that forms a part of the non-holding portion of the electrode stack to form an external space outside the electrode stack module, and then the internal space and the internal space are depressurized. This prevents the sealing sheet from deforming due to the pressure difference between the internal space and the outside of the electrode stack.

[0019] By preventing deformation in this way, the flow path of the electrolyte and other liquids can be secured during injection, thereby suppressing the occurrence of injection defects.

[0020] The embodiments of this disclosure will be described in detail below. However, this disclosure is not limited to the embodiments described below, and can be implemented in various ways within the scope of the gist of this disclosure. Furthermore, in the description of the drawings, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0021] <Process for forming the external space> A method for manufacturing an electrode stack module according to this disclosure includes setting an external space forming jig on the sealing sheet which forms a portion of the non-retaining portion of the electrode stack module, thereby forming an external space outside the electrode stack module. Here, the portion of the non-retaining portion of the electrode stack faces the liquid injection port.

[0022] As one embodiment of the present disclosure, Figure 1 shows a cross-sectional view of an electrode stack module equipped with an external space forming jig, but is not limited thereto. The electrode stack module 100, in which the electrode stack 200 is sealed by a sealing sheet 300 and a sealing member 310, has an internal space 110 inside. The internal space 110 consists of an electrode stack non-holding portion 110a and an electrode stack holding portion 110b. The sealing member 310 has a liquid injection port 350 in at least a part of it. In the electrode stack non-holding portion 110a, which is formed by the sealing member 310 having a liquid injection port 350 in at least a part of it, an external space forming jig 400 is placed outside the sealing sheet 300 that forms the electrode stack non-holding portion 110a, and an external space 410 is formed between the sealing sheet 300 and the external space forming jig 400.

[0023] (External space forming jig) In this disclosure, the external space forming jig is placed on the sealing sheet forming the electrode stack module and forms the external space.

[0024] In this disclosure, the shape of the external space forming jig can be freely selected as long as it has a recess for forming an external space. For example, when viewed from a direction perpendicular to the surface of the electrode stack module on which the external space forming jig is placed, it may be rectangular, circular, L-shaped, U-shaped, O-shaped, etc. Furthermore, an external space may be formed by placing multiple external space forming jigs on the sealing sheet forming the electrode stack module, and if multiple external space forming jigs are placed, the external space formed may be one or multiple.

[0025] Embodiments of this disclosure are shown in Figures 2 and 3, but the embodiments of this disclosure are not limited thereto. As shown in Figure 2, the external space forming jig 400 may be placed on the sealing sheet 300 that forms the electrode stack non-holding portion 110a having a liquid injection port 350 in part. Alternatively, as shown in Figure 3, the external space forming jig 400 may be placed on the sealing sheet 300 that forms all of the electrode stack non-holding portions 110a, thereby forming an external space 410.

[0026] In the present disclosure, the material of the external space forming jig can be freely selected within the range where the decompression in the external space is normally performed.

[0027] (External space) In the present disclosure, the external space is formed by an external space forming jig and a sealing sheet.

[0028] In the present disclosure, the shape of the external space is not particularly limited and may be a rectangular parallelepiped, a hemispherical shape, a semi-elliptical shape, etc. The external space may be one or plural. For example, a plurality of external spaces may be formed by one external space forming jig, or a plurality of external spaces may be formed by a plurality of external space forming jigs.

[0029] (Electrode laminate module) In the present disclosure, the electrode laminate module has an electrode laminate, a sealing sheet that seals the upper and lower surfaces of the electrode laminate, a sealing member that seals the side surface of the electrode laminate, and an internal space formed by the sealing sheet and the sealing member.

[0030] In the present disclosure, the area of the electrode laminate module in the plane direction is not particularly limited, but may be 1 cm 2 or more, 10 cm 2 or more, 50 cm 2 or more, 100 cm 2 or more, or 500 cm 2 or more, and may be 10000 cm 2 or less, 5000 cm 2 or less, 3000 cm 2 or less, 1000 cm 2 or less, or 700 cm 2 or less. In the present disclosure, the plane direction is a direction perpendicular to the stacking direction of the electrode laminate.

[0031] (Electrode laminate) In the present disclosure, the electrode laminate is not particularly limited, but may have at least a positive electrode current collector layer, a positive electrode active material layer, an electrolyte layer, a negative electrode active material layer, and a negative electrode current collector layer in this order.

[0032] In this disclosure, the battery stack may be either a liquid-based battery stack or a solid-state battery stack. In this disclosure, "solid-state battery" means a battery that uses at least a solid electrolyte as the electrolyte, and therefore a solid-state battery uses a combination of a solid electrolyte and a liquid electrolyte as the electrolyte.

[0033] In this disclosure, the area of ​​the electrode stack in the planar direction is not particularly limited, but 1 cm 2 More than 10cm 2 More than 50cm 2 More than 100cm 2 or more, or 500cm 2 The above is sufficient, and 10,000 cm 2 Below, 5000cm 2 Below, 3000cm 2 Below, 1000cm 2 The following, or 700cm 2 The following is acceptable:

[0034] (Sealing sheet) In this disclosure, the sealing sheet forms an electrode stack module.

[0035] In this disclosure, the material of the sealing sheet is not particularly limited, as long as it is a material commonly used in electrode stack modules. The shape of the sealing sheet can be freely selected as long as it can seal the electrode stack and form an internal space, and examples include rectangles.

[0036] (Sealing member) In this disclosure, the sealing member forms an electrode stack module and has an injection port that connects the internal space to the outside.

[0037] In this disclosure, the material of the sealing member is not particularly limited, as long as it is a material commonly used in electrode laminate modules.

[0038] (Internal space) In this disclosure, the internal space is formed by a sealing sheet and a sealing member and, when viewed in the planar direction, has an electrode stack holding portion that holds the electrode stack and an electrode stack non-holding portion that does not hold the electrode stack.

[0039] In this disclosure, the non-holding portion of the electrode stack is a space surrounded by the electrode stack, the sealing sheet, and the sealing member, and is formed on the outer periphery in the planar direction of the electrode stack module.

[0040] <Depressurization process> A method for manufacturing an electrode stack module according to this disclosure includes reducing the pressure of the internal space and the external space, in particular reducing the pressure of the internal space and the external space simultaneously.

[0041] In Figure 1, the internal space 110 is depressurized through the liquid injection port 350, and the external space 410 is further depressurized through the vent port 450. This reduces the pressure difference between the internal space 110 and the external space 410, preventing deformation of the sealing sheet 300 located between the internal space 110 and the external space 410.

[0042] In this disclosure, the pressure in the internal space and the pressure in the external space after depressurization are not particularly limited, but may be 10 kPa or less, 5 kPa or less, 1 kPa or less, or 0.3 kPa or less, and may be 0.0001 kPa or more, 0.001 kPa or more, 0.01 kPa or more, or 0.1 kPa or more. Also in this disclosure, the pressure in the internal space and the pressure in the external space after depressurization may be the same or different. If the pressure in the internal space and the pressure in the external space after depressurization are different, the difference between the pressure in the internal space and the pressure in the external space after depressurization may be 0.0001 kPa or more, 0.001 kPa or more, 0.05 kPa or more, or 0.03 kPa or more, and may be 10 kPa or less, 1 kPa or less, 0.7 kPa or less, 0.5 kPa or less, or 0.3 kPa or less.

[0043] <Liquid injection process> A method for manufacturing an electrode stack module according to this disclosure includes releasing the pressure in the external space while simultaneously injecting an electrolyte into the internal space through the injection port to release the pressure in the internal space.

[0044] In Figure 1, a component for supplying the electrolyte is attached to the injection port 350, and while the external space 410, which has been depressurized in the depressurization process, is returned to atmospheric pressure, the electrolyte is injected into the internal space 110 from the injection port 350, returning the internal space 110 to atmospheric pressure. This allows the electrolyte to be injected into the internal space 110. The electrolyte injected into the internal space 110 diffuses into the electrode stack non-holding portion 110a and the electrode stack holding portion 110b.

[0045] (electrolyte) In this disclosure, the electrolyte is injected into the internal space of the electrode stack module during the injection process.

[0046] In this disclosure, the electrolyte is not particularly limited, but it preferably contains a supporting salt and a solvent.

[0047] The supporting salt (lithium salt) for the lithium-ion conductive electrolyte is not particularly limited, but examples include inorganic lithium salts and organic lithium salts. Examples of inorganic lithium salts include, but are not limited to, LiPF6, LiBF4, LiClO4, and LiAsF6. Examples of organic lithium salts include, but are not limited to, LiCF3SO3, LiN(CF3SO2)2, LiN(C2F5SO2)2, LiN(FSO2)2, and LiC(CF3SO2)3.

[0048] The solvent used in the electrolyte is not particularly limited, but examples include cyclic carbonates and linear carbonates. Examples of cyclic carbonates include ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate (BC), but are not limited to these. Examples of linear carbonates include dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC), but are not limited to these. The electrolyte is not particularly limited, but one type may be used alone, or two or more types may be used in combination. [Explanation of Symbols]

[0049] 100 Electrode Stack Module 110 Interior space 110a Non-retaining portion of electrode laminate 110b Electrode stack holding part 200 electrode stack 210 Cathode active material layer 220 Negative electrode active material layer 230 Current collector layer 240 Separator 300 sealing sheets 310 Sealing member 350 Injection port 400 External space forming jig 410 External space 450 Ventilation opening

Claims

1. A method for manufacturing an electrode stack module, The electrode stack module, Electrode stack, A sealing sheet that seals the upper and lower surfaces of the electrode stack, A sealing member for sealing the side surface of the electrode stack, and The internal space formed by the sealing sheet and the sealing member, It has, The sealing member has a liquid injection port that connects the internal space to the outside, The internal space, when viewed in the planar direction, has an electrode stack holding portion that holds the electrode stack and an electrode stack non-holding portion that does not hold the electrode stack. The non-holding portion of the electrode stack is a space surrounded by the electrode stack, the sealing sheet, and the sealing member, and is formed on the outer periphery in the planar direction of the electrode stack module. The method described above is An external space forming jig is placed on the sealing sheet that forms a part of the non-holding portion of the electrode stack to form an external space outside the electrode stack module, where the part of the non-holding portion of the electrode stack faces the liquid injection port. Depressurizing the internal space and the external space, The process involves releasing the pressure in the external space while simultaneously injecting the electrolyte into the internal space through the injection port to release the pressure in the internal space. including, A method for manufacturing an electrode stack module.

2. The method according to claim 1, wherein the difference between the pressure in the internal space after depressurization and the pressure in the external space is 10 kPa or less.

3. The surface area of ​​the electrode stack module is 200 cm². ２ The method according to claim 1.

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