Electrode assembly isostatic pressing method using protective member as outer sacrificial frame, and all-solid-state battery including protective member

Abstract

The present invention provides an isostatic pressing method of an electrode assembly including a positive electrode including a positive electrode current collector and a positive electrode active material layer, a negative electrode including a positive electrode current collector and a negative electrode active material layer, and a solid electrolyte layer, the electrode assembly has a laminated form in which the solid electrolyte layer is laminated on the negative electrode active material layer, one surface of the solid electrolyte is bonded to the negative electrode active material layer, the positive electrode layer is laminated on the other surface of the solid electrolyte layer, and the positive electrode active material layer is bonded to the other surface of the solid electrolyte layer. Isostatic pressing is performed in a state in which a belt-type protective member vertically extending from the outer peripheral surface of the protruding end of the negative electrode to the positive electrode is fastened, and a space formed by the step is located between the protective member and the positive electrode; the invention also provides an all-solid-state battery comprising the electrode assembly and the protective component.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0129329, filed on September 26, 2023, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] The present invention relates to an isostatic pressing method for an electrode assembly having a protective component as an external sacrificial frame, and an all-solid-state battery including the protective component. Background Technology

[0004] In recent years, secondary batteries have become indispensable as portable power sources for computers and mobile devices, and as power sources or energy storage sources for vehicles such as electric vehicles (EVs), hybrid vehicles (HVs), and plug-in hybrid vehicles (PHVs).

[0005] In particular, lithium-ion batteries have high energy density and high-speed output, and with their widespread use, the demand for further performance enhancements and reliability improvements is increasing.

[0006] In recent years, in order to improve the safety of lithium-ion secondary batteries, all-solid-state batteries have been commercialized. All-solid-state batteries do not use flammable electrolytes as electrolytes, but instead use solid electrolytes made of ceramics or ion-conductive polymers.

[0007] All-solid-state batteries have a layered solid electrolyte between the positive and negative electrode active material layers, which forms the electrode. Although these solid electrolyte layers, as well as the positive and negative electrode active material layers, can be formed into a dense thin film using CVD, they are usually manufactured by bonding powder electrode component materials together using binders, considering cost and productivity.

[0008] A key characteristic of all-solid-state batteries is the high interfacial resistance between the solid electrolyte layer and the positive and negative electrode active material layers. Furthermore, in all-solid-state batteries manufactured using powder materials, interfacial resistance occurs between particles even within the solid electrolyte layer and the positive and negative electrode active material layers. Therefore, to reduce this interfacial resistance, the following process is performed: the electrodes, which are stacked with positive electrode active material layers, solid electrolyte layers, and negative electrode active material layers, are pressurized under high pressure (e.g., a surface pressure of approximately 100–500 MPa) to improve the charge density of each layer.

[0009] When the electrode is pressurized, since a tensile stress can be applied in a direction orthogonal to the pressurizing direction, a short circuit occurs when the end portion of the positive electrode active material layer and the end portion of the negative electrode active material layer, which face each other through the solid electrolyte layer, come into contact with each other. Therefore, for example, the width of one active material layer (for example, the positive electrode active material layer) is designed to be small to prevent a short circuit. In addition, a configuration in which the end portion of the solid electrolyte layer or the end portions of the positive electrode active material layer and the negative electrode active material layer are covered with an insulator is also proposed.

[0010] Furthermore, the pressurizing process is usually performed by isostatic pressurization by applying high pressure to the outermost edge of the electrode, resulting in edge stretching and thinning or rounding, and cracking in the electrode active material layer and the solid electrolyte layer.

[0011] [Related Art Documents]

[0012] [Patent Documents]

[0013] Japanese Patent Publication No. 2015-050149 SUMMARY

[0014] PROBLEMS TO BE SOLVED BY THE INVENTION

[0015] The present invention aims to solve the above-described problems in the related art and aims to provide an isostatic pressurization method for an electrode assembly in which, by applying a specific type of protective member as an external sacrificial frame to the electrode assembly in an isostatic pressurization process for an all-solid-state battery, a short circuit between the end portions of the positive electrode active material layer and the negative electrode active material layer is prevented, and the problem of stretching, thinning, or rounding of the outermost edge of the electrode is also prevented; and the present invention also provides an all-solid-state battery including the protective member.

[0016] TECHNICAL SOLUTION

[0017] To achieve the above object, the present invention provides an isostatic pressurization method for an electrode assembly, the electrode assembly including: a positive electrode including a positive electrode current collector and a positive electrode active material layer, a negative electrode including a negative electrode current collector and a negative electrode active material layer, and a solid electrolyte layer, wherein the solid electrolyte layer is laminated to bind one face to the negative electrode active material layer, and the positive electrode is laminated to bind the other face of the solid electrolyte layer to the positive electrode active material layer, wherein the electrode assembly has a stacked form in which the negative electrode protrudes beyond the end portion of the positive electrode to form a step, wherein the isostatic pressurization is performed in the presence of a tape-type protective member that extends perpendicularly from the outer peripheral surface of the negative electrode end portion protruding from the electrode assembly to the positive electrode.

[0018] In addition, the present application provides an all-solid-state battery including an electrode assembly including a positive electrode including a positive electrode current collector and a positive electrode active material layer, a negative electrode including a negative electrode current collector and a negative electrode active material layer, and a solid electrolyte layer, wherein the solid electrolyte layer is laminated to bind one face to the negative electrode active material layer, and the positive electrode is laminated to bind the other face of the solid electrolyte layer to the positive electrode active material layer, wherein the electrode assembly has a stacked form in which the negative electrode protrudes beyond the end portion of the positive electrode to form a step; and a band-type protection member vertically extending from the outer circumferential surface of the negative electrode end portion protruding from the electrode assembly to the positive electrode.

[0019] Advantageous Effects

[0020] The isostatic pressing method of the electrode assembly of the present application provides the following effects: by applying a specific type of protection member as an external sacrificial frame to the electrode assembly in the isostatic pressing process of the all-solid-state battery, short circuiting between the end portions of the positive electrode active material layer and the negative electrode active material layer due to cracking is prevented, and also the problem of the outermost edge of the cell being stretched, thinned, or rounded is prevented.

[0021] Furthermore, the all-solid-state battery including the protection member prevents short circuiting between the end portions of the positive electrode active material layer and the negative electrode active material layer, and also prevents the problem of the outermost edge of the cell being stretched, thinned, or rounded, thereby improving the safety and operating characteristics of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a diagram illustrating a conventional method of isostatic pressing of an electrode assembly.

[0023] Figure 2 is a diagram illustrating a problem caused by a conventional isostatic pressing method.

[0024] Figure 3 is a diagram illustrating one example of an isostatic pressing method of an electrode assembly of the present application.

[0025] Figure 4 is a cross-sectional view illustrating the shape of an electrode assembly of the present application.

[0026] Figure 5 and Figure 6 is a diagram illustrating one example of an electrode assembly of the present application having a protection member.

[0027] Figure 7 is a diagram illustrating another example of an electrode assembly of the present application having a protection member.

[0028] Figure 8 andFigure 9 is a cross-sectional view illustrating one example of a full solid-state battery according to the present application. DETAILED DESCRIPTION

[0029] Hereinafter, examples of the present application will be described in detail with reference to the accompanying drawings so as to be implemented by those skilled in the art. However, the present application can be implemented in various different forms and is not limited to the examples described herein. Throughout the specification, like components are designated with like reference numerals.

[0030] When a component is referred to as being "connected to", "included in", or "mounted on" another component, it should be understood that it can be directly connected or mounted on the other component, but other components can exist between them. On the other hand, when a component is referred to as being "directly connected to", "directly included in", or "directly mounted on" another component, it should be understood that no other components exist between them. Other expressions describing the relationship between components, such as "on top of" and "directly on top of", or "between" and "directly between", or "adjacent to" and "directly adjacent to", should be similarly interpreted.

[0031] As shown in FIGS. 1 and 2, the electrode assembly (50) of the present application includes a positive electrode (10) including a positive electrode current collector (12) and a positive electrode active material layer (14), a negative electrode (20) including a negative electrode current collector (22) and a negative electrode active material layer (24), and a solid electrolyte layer (30), Figure 3 and Figure 5 As shown in FIGS. 1 and 2, the electrode assembly (50) of the present application includes a positive electrode (10) including a positive electrode current collector (12) and a positive electrode active material layer (14), a negative electrode (20) including a negative electrode current collector (22) and a negative electrode active material layer (24), and a solid electrolyte layer (30), wherein the solid electrolyte layer (30) is laminated to bind one face to the negative electrode active material layer (24), and the positive electrode (10) is laminated to bind the other face of the solid electrolyte layer (30) to the positive electrode active material layer (14), wherein the electrode assembly (50) has a stacked form in which the end of the negative electrode (20) protrudes beyond the positive electrode (10) to form a step, wherein the isostatic pressing is performed in the presence of a band-type protection member (40) extending perpendicularly from the outer circumferential face of the end of the negative electrode (20) of the protruding electrode assembly (100) to the positive electrode (10).

[0032] In one example of the present application, the protection member (40) can extend to the outermost surface of the positive electrode current collector (12), for example.

[0033] In one example of the present application, the electrode assembly (100) is in the form of a dual cell as shown in FIG. 3, Figure 8 ​In this process, a solid electrolyte layer (30) is stacked to form a negative electrode active material layer (24) with one side bonded to the negative electrode current collector (22), and a positive electrode (10) is stacked to form a positive electrode active material layer (14) with the other side of the solid electrolyte layer (30) bonded to it. The protective component (40) may be in the form of a strip that extends vertically from the outer peripheral surface of the negative electrode (20) end of the protruding electrode assembly (100) to the outermost surface of the two positive electrode current collectors (12).

[0034] like Figure 3 As shown, the electrode assembly (50) with protective component (40) is housed inside a bag-shaped housing (60) or an isostatic pressure membrane (70) and is pressurized while being fixed to the isostatic pressure clamp (200).

[0035] like Figure 1 and Figure 2 As shown, in the conventional isostatic pressing method for the electrode assembly (50), when the electrode assembly is subjected to isostatic pressing, tensile stress is applied in a direction orthogonal to the pressing direction, and due to cracking, short circuits occur as the ends of the positive and negative electrode active material layers facing each other through the solid electrolyte layer come into contact. In addition, the edges of the electrode assembly are stretched and become thinner or rounded, causing cracks in the electrode active material layer and the solid electrolyte layer.

[0036] The present invention solves the above-mentioned problems, and is characterized in that it... Figure 3 and Figure 5 The strip-shaped protective component (40) shown is subjected to isostatic pressurization as an external sacrificial frame.

[0037] In one embodiment of the invention, a solid electrolyte layer (30) is stacked over the entire area of ​​the negative electrode active material layer (24), thereby forming a step between the solid electrolyte layer (30) and the positive electrode (10).

[0038] In one example of the present invention, such as Figure 3 and 5 As shown, the space formed by the step can be located between the protective component (40) and the positive electrode (10). The space formed by the step acts as a buffer space for the high pressure applied by isostatic pressing, preventing the outermost edge of the electrode assembly (50) from stretching, thinning and rounding, and preventing the electrode active material layer and solid electrolyte layer from cracking.

[0039] In one embodiment of the invention, the protective component (40) is readily attached to or detached from the electrode assembly (50) under isostatic pressure. In other words, the protective component can be disposed in the battery case (e.g., a pouch) while being secured to the electrode assembly, but in some cases, it can be removed after isostatic pressure is applied. In this case, the strip-type protective component (40) of the present invention is preferred because it is easy to attach and detach and is recyclable.

[0040] In one example of the present invention, such as Figure 7 As shown, the space formed by the steps can be filled with the lateral extension (42) of the protective component (40). The lateral extension (42) prevents the outermost edge of the electrode assembly (50) from stretching, thinning and rounding due to high pressure by filling the space formed by the step, and prevents the electrode active material layer and the solid electrolyte layer from cracking.

[0041] In one embodiment of the invention, the protective component (40) preferably has a contraction range equal to or similar to that of the electrode assembly when compressed. Specifically, the degree of contraction of the protective component (40) when compressed is preferably 0.8 to 1.2 times, more preferably 0.9 to 1.1 times, that of the electrode assembly when compressed.

[0042] For example, protective components with a compressive force deformation (CFD) 50% of 2000 kPa to 4000 kPa can be used. The CFD measurement method described above is one of the methods for evaluating material stiffness. For example, if a force of 3000 kPa is required to shrink the material to 50% of its initial thickness, then CFD 50% is defined as 3000 kPa.

[0043] The protective member (40) can preferably extend vertically from the outer peripheral surface of the negative electrode (20) end of the protruding electrode assembly (100) to the outermost surface of the positive current collector (10), but considering elasticity, it can also extend slightly above the outermost surface of the positive current collector (12). In this case, when a high pressure is applied by isostatic pressing, the protective member (40) can contract due to elasticity to provide the intended effect of the invention. Specifically, it can preferably have a length that compresses to the outermost surface of the positive current collector (10) under isostatic pressing. Furthermore, if it extends to a position slightly lower than the outermost surface of the positive current collector (12), the same or similar effect can be expected.

[0044] In one embodiment of the invention, the material of the protective component is not particularly limited, but, for example, polymer materials such as rubber, silicone, Gore-Tex, PVC, EVA, etc. may be preferred.

[0045] In one example of the present invention, such as Figure 5 andFigure 7 As shown, the protective component (40) may be formed with through holes or grooves, so that the negative electrode tab formed on the negative electrode current collector (22) and the positive electrode tab formed on the positive electrode current collector (12) protrude to the outside of the protective component (40).

[0046] The present invention also provides, for example Figure 8 The all-solid-state battery shown It includes an electrode assembly (50), which comprises: a positive electrode (10) including a positive current collector (12) and a positive active material layer (14), a negative electrode (20) including a negative current collector (22) and a negative active material layer (24), and a solid electrolyte layer (30). In this process, a solid electrolyte layer (30) is stacked to bond one side to the negative electrode active material layer (24), and a positive electrode (10) is stacked to bond the other side of the solid electrolyte layer (30) to the positive electrode active material layer (14). The electrode assembly (50) has a stacked form where the negative electrode (20) protrudes beyond the end of the positive electrode (10), thus forming a stepped structure; and A strip-shaped protective component (40) extends vertically from the outer peripheral surface of the negative electrode (20) end of the protruding electrode assembly (100) to the positive electrode (10).

[0047] In one embodiment of the present invention, if the electrode assembly (100) is as follows: Figure 8 The dual-cell configuration shown is as follows. In this process, a solid electrolyte layer (30) is stacked to form a negative electrode active material layer (24) with one side bonded to the negative electrode current collector (22), and a positive electrode (10) is stacked to form a positive electrode active material layer (14) with the other side of the solid electrolyte layer (30) bonded to it. The protective component (40) may be in the form of a strip that extends vertically from the outer peripheral surface of the negative electrode (20) end of the protruding electrode assembly (100) to the outermost surface of the two positive electrode current collectors (12).

[0048] For the all-solid-state battery of the present invention, all the above-described isostatic pressing methods can be applied, therefore, redundant descriptions will be omitted.

[0049] In one embodiment of the invention, the solid electrolyte layer (30) is stacked over the entire area of ​​the negative electrode active material layer (24), thereby also forming a step between the solid electrolyte layer (30) and the positive electrode (10).

[0050] In one embodiment of the invention, the space formed by the step may be located between the protective component (40) and the positive electrode (10).

[0051] like Figure 8As shown, the all-solid-state battery (100) may have a structure in which electrode components (50) and protective components (40) are assembled and stored in a battery case (e.g., a pouch-like case).

[0052] In one embodiment of the invention, the protective component (40) preferably has a contraction range equal to or similar to that of the electrode assembly when compressed. Specifically, the degree of contraction of the protective component (40) when compressed is preferably 0.8 to 1.2 times, more preferably 0.9 to 1.1 times, that of the electrode assembly when compressed.

[0053] For example, protective components with a compressive force deformation (CFD) 50% of 2000 kPa to 4000 kPa can be used. The CFD measurement method described above is one of the methods for evaluating material stiffness. For example, if a force of 3000 kPa is required to shrink the material to 50% of its initial thickness, then CFD 50% is defined as 3000 kPa.

[0054] The protective member (40) can preferably extend vertically from the outer peripheral surface of the negative electrode (20) end of the protruding electrode assembly (100) to the outermost surface of the positive current collector (10), but considering elasticity, it can also extend slightly above the outermost surface of the positive current collector (12). In this case, when a high pressure is applied by isostatic pressing, the protective member (40) can contract due to elasticity to provide the intended effect of the invention. Specifically, it can preferably have a length that compresses to the outermost surface of the positive current collector (10) under isostatic pressing. Furthermore, if it extends to a position slightly lower than the outermost surface of the positive current collector (12), the same or similar effect can be expected.

[0055] In one embodiment of the present invention, the all-solid-state battery may be a lithium-ion all-solid-state battery.

[0056] Although the invention has been described with reference to the preferred embodiments above, various modifications or variations can be made without departing from the spirit and scope of the invention. Therefore, the appended claims are intended to cover such modifications or variations, provided they fall within the spirit of the invention.

[0057] [Figure Labels]

[0058] 10: Positive electrode 10: Positive electrode

[0059] 12: Positive electrode current collector; 14: Positive electrode active material layer

[0060] 20: Negative electrode; 32: Negative electrode current collector

[0061] 34: Negative electrode active material layer; 40: Protective component

[0062] 42: Lateral extension of protective component; 50: Electrode assembly

[0063] 60: Bag-shaped shell; 70: Membrane for isostatic pressing.

[0064] 100: All-solid-state battery; 200: Isostatic pressure clamp.

Claims

1. A method for isostatically pressurizing an electrode assembly, the electrode assembly comprising: a positive electrode including a positive current collector and a positive active material layer, a negative electrode including a negative current collector and a negative active material layer, and a solid electrolyte layer. in, The solid electrolyte layer is stacked to bond one side to the negative electrode active material layer, and the positive electrode is stacked to bond the other side of the solid electrolyte layer to the positive electrode active material layer. The electrode assembly is stacked, wherein the negative electrode protrudes beyond the end of the positive electrode to form a step. The isostatic pressing is performed in the presence of a strip-shaped protective component that extends vertically from the outer peripheral surface of the negative electrode protruding from the electrode assembly to the positive electrode. The space formed by the step is located between the protective component and the positive electrode.

2. The isostatic pressing method for the electrode assembly as described in claim 1, wherein, The electrode assembly with the protective component is housed inside a bag-shaped housing or an isostatic pressure membrane and pressurized while being fixed to an isostatic pressure clamp.

3. The isostatic pressing method for the electrode assembly as described in claim 1, wherein, The solid electrolyte layer is stacked over the entire area of ​​the negative electrode active material layer, thereby forming a step between the solid electrolyte layer and the positive electrode.

4. The isostatic pressing method for the electrode assembly as described in claim 1, wherein, The protective component contracts to a degree that is 0.8 to 1.2 times the degree that the electrode assembly contracts to a degree that is pressurized.

5. The isostatic pressing method for the electrode assembly as described in claim 1, wherein, In the protective component, the compressive deformation (CFD) 50% is 2000 kPa to 4000 kPa.

6. The isostatic pressing method for the electrode assembly as described in claim 1, wherein, The protective component is made of at least one selected from the group consisting of rubber, silicone, Gore-Tex and polymer materials.

7. An all-solid-state battery comprising an electrode assembly, the electrode assembly including: The cathode comprises a positive current collector and a positive active material layer, the anode comprises a negative current collector and a negative active material layer, and a solid electrolyte layer. Specifically, the solid electrolyte layer is stacked to bond one side to the negative electrode active material layer, and the positive electrode is stacked to bond the other side of the solid electrolyte layer to the positive electrode active material layer. The electrode assembly is stacked, wherein the negative electrode protrudes beyond the end of the positive electrode to form a step; and, A strip-shaped protective component extends vertically from the outer peripheral surface of the negative terminal protruding from the electrode assembly to the positive terminal. The space formed by the step is located between the protective component and the positive electrode.

8. The all-solid-state battery of claim 7, wherein the solid electrolyte layer is stacked over the entire area of ​​the negative electrode active material layer, thereby forming a step between the solid electrolyte layer and the positive electrode.

9. The all-solid-state battery as described in claim 7, wherein, The all-solid-state battery is a lithium-ion all-solid-state battery.

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