Manufacturing method for electrode stack modules

Abstract

This disclosure aims to provide a method for manufacturing an electrode stack module that improves the pourability and impregnation properties of an electrolyte containing ethylene carbonate. [Solution] The present disclosure's method for manufacturing an electrode stack module comprises (a) stacking a positive electrode active material layer 240, a separator 230, and a negative electrode active material layer 220 in this order to produce an electrode stack 200, and (b) pouring an electrolyte into an electrode stack module 100 comprising the electrode stack 200 and an outer casing, wherein in step (a), at least one of the positive electrode active material layer 240, the separator 230, and the negative electrode active material layer 220 has an ethylene carbonate layer 300 on at least a portion of its surface.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing an electrode laminate module.

Background Art

[0002] An electrode laminate module is, for example, a battery in which an electrode laminate having 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 is housed in an exterior container or the like.

[0003] For example, in Patent Document 1, a plurality of current collectors provided with active material layers, and a plurality of sealing members having a frame shape surrounding the active material layer as viewed from the thickness direction of the current collector and having an extending portion extending outward from the outer edge of the current collector are provided. A preparation step of preparing a laminate in which the sealing member is disposed between each of the plurality of current collectors, and a melting step of melting the plurality of sealing members to form a side surface including a communication port that is composed of the plurality of sealing members and communicates the inside and outside of the laminate. And a molding step of forming a molding surface against which an equipment-side nozzle is pressed in a region surrounding the communication port of the side surface formed by melting the plurality of sealing members. In the melting step, the plurality of sealing members are melted by non-contact heating, and in the molding step, in a state where the sealing members are melted, a pressing member having a temperature lower than the melting point of the sealing members is pressed against the side surface to form the molding surface. A method for manufacturing an energy storage device is disclosed. According to the method described in Patent Document 1, it is said that productivity improvement and sealing performance can be achieved.

[0004] For example, Patent Document 2 describes a first electrode unit and a second electrode unit stacked on top of each other, a separator interposed between the first electrode unit and the second electrode unit, and an electrolyte held in the first electrode unit and the second electrode unit, wherein the first electrode unit has a first current collector including a first surface, a first active material layer formed on the first surface, and a first resin frame provided on the first surface so as to surround the first active material layer, and the second electrode unit has a second current collector including a second surface, a second active material layer formed on the second surface having a different polarity from the first active material layer, and the first resin frame provided on the first surface so as to surround the second active material layer A storage cell is disclosed having a second resin frame provided on two sides, wherein the first electrode unit and the second electrode unit are laminated such that the first active material layer and the second active material layer face each other via a separator, the first resin frame and the second resin frame are joined to each other to seal the space between the first current collector and the second current collector, the electrolyte is disposed in the space, the height of the first active material layer from the first side is lower than the height of the first resin frame from the first side, and the height of the second active material layer from the second side is higher than the height of the second resin frame from the second side. According to the storage cell described in Patent Document 2, it is possible to drop-inject excess electrolyte.

[0005] For example, Patent Document 3 discloses a method for manufacturing a lithium-ion secondary battery, which includes manufacturing a negative electrode containing graphite, constructing an electrode group including the negative electrode and the positive electrode, preparing an electrolyte containing ethylene carbonate but not containing 1,2-dimethoxyethane, impregnating the electrode group with the electrolyte, reductively decomposing at least a portion of the ethylene carbonate by charging the electrode group impregnated with the electrolyte, and manufacturing a lithium-ion secondary battery by adding 1,2-dimethoxyethane to the electrolyte after charging. According to the method described in Patent Document 3, co-insertion of 1,2-dimethoxyethane is suppressed. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2023-000059 [Patent Document 2] Japanese Patent Publication No. 2021-140971 [Patent Document 3] Japanese Patent Publication No. 2018-073464 [Overview of the project] [Problems that the invention aims to solve]

[0007] In recent years, electrolytes containing ethylene carbonate have sometimes been used. Electrolytes containing ethylene carbonate have high viscosity, and therefore, when an electrolyte containing ethylene carbonate is injected into an electrode stack module comprising an electrode stack and an outer casing, the injection and impregnation properties of the electrolyte may decrease.

[0008] Therefore, the object of this disclosure is to provide a method for manufacturing an electrode stack module that improves the pourability and impregnation properties of an electrolyte containing ethylene carbonate. [Means for solving the problem]

[0009] This disclosure aims to achieve the above objectives by the following means:

[0010] (Aspect 1) (a) Laminating the positive electrode active material layer, the separator, and the negative electrode active material layer in this order to produce an electrode laminate, and (b) Pouring an electrolyte into the electrode stack module comprising the electrode stack and the outer casing, including and In step (a), at least one of the positive electrode active material layer, the separator, and the negative electrode active material layer has an ethylene carbonate layer on at least a portion of its surface. A method for manufacturing an electrode stack module. (Aspect 2) The method according to embodiment 1, wherein the ethylene carbonate content of the electrolyte is 15% by volume or less. (Aspect 3) The method according to embodiment 2, wherein the electrolyte does not contain ethylene carbonate. (Aspect 4) The method according to any one of embodiments 1 to 3, wherein the ethylene carbonate layer is disposed on only a portion of the surface of at least one of the positive electrode active material layer, the separator, and the negative electrode active material layer. (Aspect 5) The method according to embodiment 4, wherein the ethylene carbonate layer is arranged in a predetermined pattern on at least one surface of the positive electrode active material layer, the separator, and the negative electrode active material layer. [Effects of the Invention]

[0011] According to this disclosure, it is possible to provide a method for manufacturing an electrode stack module that improves the pourability and impregnation properties of an electrolyte containing ethylene carbonate. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a schematic diagram illustrating this embodiment. [Figure 2] Figure 2 is a schematic diagram illustrating this embodiment. [Figure 3A] Figure 3A is a schematic diagram illustrating a predetermined pattern of ethylene carbonate arrangement. [Figure 3B] Figure 3B is a schematic diagram illustrating a predetermined pattern of ethylene carbonate arrangement. [Figure 3C] Figure 3C is a schematic diagram illustrating a predetermined pattern of ethylene carbonate arrangement. [Figure 3D] Figure 3D is a schematic diagram illustrating a predetermined pattern of ethylene carbonate arrangement. [Modes for carrying out the invention]

[0013] ≪Method for Manufacturing an Electrode Stack Module≫ The method of the present disclosure for manufacturing an electrode stack module is as follows: (a) Stacking a positive electrode active material layer, a separator, and a negative electrode active material layer in this order to produce an electrode stack, and (b) Injecting an electrolytic solution into an electrode stack module including the above electrode stack and an exterior body. It includes, and In step (a), at least one of the positive electrode active material layer, the separator, and the negative electrode active material layer has an ethylene carbonate layer on at least a part of its surface.

[0014] According to the method of the present disclosure for manufacturing the above electrode stack module, the injectability and impregnation property of an electrolytic solution containing ethylene carbonate can be improved.

[0015] In the conventional method for manufacturing an electrode stack module, an electrolytic solution containing ethylene carbonate is injected through an injection port. In this case, since the viscosity of the electrolytic solution containing ethylene carbonate is higher than that of an electrolytic solution not containing ethylene carbonate, it is considered that the injectability of the electrolytic solution is low and the impregnation property into the active material layer is low.

[0016] On the other hand, according to the method of the present disclosure, when manufacturing an electrode stack, at least one of the positive electrode active material layer, the separator, and the negative electrode active material layer has an ethylene carbonate layer on at least a part of its surface. As a result, the content rate of ethylene carbonate in the electrolytic solution to be injected can be reduced, and thus the viscosity of the electrolytic solution to be injected can be reduced. Since the melting point of ethylene carbonate is about 36°C, a solid ethylene carbonate layer can be formed at room temperature.

[0017] Furthermore, by placing the ethylene carbonate layer on only a portion of the surface of at least one of the positive electrode active material layer, the separator, and the negative electrode active material layer, an electrolyte injection path can be secured in the gap between the ethylene carbonate layers between the positive electrode active material layer and the separator and / or between the separator and the negative electrode active material layer, thereby further improving the electrolyte injection and impregnation properties.

[0018] 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.

[0019] <Lamination process> In the method for manufacturing an electrode stack module according to this disclosure, first, an electrode stack is fabricated by stacking a positive electrode active material layer, a separator, and a negative electrode active material layer in that order.

[0020] In this disclosure, in the lamination process, at least one of the positive electrode active material layer, the separator, and the negative electrode active material layer has an ethylene carbonate layer on at least a portion of its surface. Preferably, at least one of the positive electrode active material layer, the separator, and the negative electrode active material layer has an ethylene carbonate layer on only a portion of its surface. However, at least one of the positive electrode active material layer, the separator, and the negative electrode active material layer may have an ethylene carbonate layer covering its entire surface.

[0021] Figure 1 shows a cross-sectional view of the electrode stack of this embodiment, but the embodiments in this disclosure are not limited thereto. An electrode stack 200 is obtained by stacking a current collector 210, a negative electrode active material layer 220 having an ethylene carbonate layer 300 on its surface, a separator 230, and a positive electrode active material layer 240 in this order. The electrode stack 200 is constructed by stacking the current collector 210, the negative electrode active material layer 220, the ethylene carbonate layer 300, the separator 230, and the positive electrode active material layer 240 in this order.

[0022] (Electrode stack) In this disclosure, the electrode stack is not particularly limited, but may have a positive electrode active material layer, an electrolyte layer, and a negative electrode active material layer in at least this order.

[0023] In this disclosure, the electrode stack may be a liquid electrode stack or a solid electrode stack. In this disclosure, "solid battery" means a battery that uses at least a solid electrolyte as the electrolyte, and therefore a solid battery uses a combination of a solid electrolyte and a liquid electrolyte as the electrolyte.

[0024] (Ethylene carbonate layer) In this disclosure, at least one of the positive electrode active material layer, the separator, and the negative electrode active material layer has an ethylene carbonate layer on at least a portion of its surface.

[0025] In this disclosure, the ethylene carbonate layer may be arranged in a predetermined pattern on at least one surface of the positive electrode active material layer, the separator, and the negative electrode active material layer. In this disclosure, the predetermined pattern of the ethylene carbonate layer is not particularly limited. Figures 3A to 3D show the negative electrode active material layer as viewed from the stacking direction of the electrode stack when the ethylene carbonate layer is present on a portion of the surface of the negative electrode active material layer, but the embodiments in this disclosure are not limited thereto. In this disclosure, the predetermined pattern of the ethylene carbonate layer may be, for example, dot-like (Figure 3A), stripe-like (Figure 3B), frame-like (Figure 3C), or covering the entire surface (Figure 3D), and may also be spiral-like, checkerboard-like, wavy-like, mesh-like, geometric-like, etc.

[0026] <Liquid injection process> In the method for manufacturing an electrode stack module according to this disclosure, an electrolyte is then poured into the electrode stack module, which comprises the electrode stack and the outer casing.

[0027] Figure 2 shows a cross-sectional view of the electrode stack of this embodiment, but the embodiments of this disclosure are not limited thereto. The electrode stack 200 has an ethylene carbonate layer 300 in part between the negative electrode active material layer 220 and the separator 230, and the ethylene carbonate layer 300 creates voids in the areas between the negative electrode active material layer 220 and the separator 230 where the ethylene carbonate layer 300 is not placed. In the electrode stack module 100 in which this electrode stack 200 is sealed with a sealing member 150, when electrolyte is injected in the liquid injection process, the injected electrolyte can diffuse throughout the electrode stack 200 using these voids as a pathway. This makes it easier for the electrolyte to impregnate the negative electrode active material layer 220 and / or the positive electrode active material layer 240.

[0028] In this disclosure, an ethylene carbonate layer is placed within the electrode stack, and this ethylene carbonate layer dissolves in the electrolyte injected during the injection process over a sufficient period of time. Therefore, even if the ethylene carbonate content of the electrolyte injected during the injection process is less than the desired content by the amount of ethylene carbonate placed within the electrode stack, the electrolyte within the electrode stack module can have the desired ethylene carbonate content.

[0029] (electrolyte) In this disclosure, the electrolyte is injected into an electrode stack module comprising an electrode stack and an outer casing during the injection process.

[0030] In this disclosure, the electrolyte is not particularly limited, but it preferably contains a supporting salt and a solvent.

[0031] 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.

[0032] 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.

[0033] In this disclosure, if the electrolyte contains ethylene carbonate, the ethylene carbonate content of the electrolyte may be 0% by volume or more, 5% by volume or more, 7% by volume or more, 10% by volume or more, 15% by volume or more, or 20% by volume or more, and may be 50% by volume or less, 40% by volume or less, 30% by volume or less, 25% by volume or less, 20% by volume or less, 15% by volume or less, or 10% by volume or less. Furthermore, in this disclosure, the electrolyte injected in the injection step does not have to contain ethylene carbonate. [Explanation of Symbols]

[0034] 100 Electrode Stack Module 150 Sealing member 200 electrode stack 210 Current collector 220 Negative electrode active material layer 230 Separator 240 Cathode active material layer 300 Ethylene carbonate layer

Claims

1. (a) Laminating the positive electrode active material layer, the separator, and the negative electrode active material layer in this order to produce an electrode laminate, and (b) Pouring an electrolyte into the electrode stack module comprising the electrode stack and the outer casing, including and In step (a), at least one of the positive electrode active material layer, the separator, and the negative electrode active material layer has an ethylene carbonate layer on at least a portion of its surface. A method for manufacturing an electrode stack module.

2. The method according to claim 1, wherein the ethylene carbonate content of the electrolyte is 15% by volume or less.

3. The method according to claim 2, wherein the electrolyte does not contain ethylene carbonate.

4. The method according to any one of claims 1 to 3, wherein the ethylene carbonate layer is disposed on only a portion of the surface of at least one of the positive electrode active material layer, the separator, and the negative electrode active material layer.

5. The method according to claim 4, wherein the ethylene carbonate layer is arranged in a predetermined pattern on at least one surface of the positive electrode active material layer, the separator, and the negative electrode active material layer.

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