EP-4738524-A1 - COMPOSITE ELECTRODE SHEET AND PREPARATION METHOD AND PREPARATION DEVICE THEREFOR, AND LITHIUM ION BATTERY

EP4738524A1EP 4738524 A1EP4738524 A1EP 4738524A1EP-4738524-A1

Abstract

Disclosed are a preparation method for a composite electrode sheet, a composite electrode sheet preparation apparatus, used for preparing the composite electrode sheet, and a lithium-ion battery comprising the composite electrode sheet. In a dry rolling process, an electrode sheet is conveyed by means of an electrode sheet unwinding mechanism, a solid electrolyte membrane is conveyed by means of a solid electrolyte membrane unwinding mechanism, and then an elastic member provided between a shaping roller and the solid electrolyte membrane is used to roll the solid electrolyte membrane located at a side of the electrode sheet onto the electrode sheet, to obtain a composite electrode sheet.

Inventors

SHI, ZHAN
FENG, YUCHUAN
LI, ZHENG

Assignees

Suzhou Qingtao New Energy S&T Co., Ltd.

Dates

Publication Date: 20260506
Application Date: 20240604

Claims (20)

A preparation method for a composite electrode sheet, comprising: conveying an electrode sheet by means of an electrode sheet unwinding mechanism, so that the electrode sheet passes through a gap in the middle of a shaping roller assembly; conveying a solid electrolyte membrane by means of a solid electrolyte membrane unwinding mechanism located at a side of the electrode sheet unwinding mechanism, so that the solid electrolyte membrane passes through a gap between the shaping roller assembly and the electrode sheet; and compositing the electrode sheet and the solid electrolyte membrane by means of the shaping roller assembly, to obtain a composite electrode sheet, wherein an elastic member is provided between the shaping roller assembly and the solid electrolyte membrane rolled on the electrode sheet.
The preparation method according to claim 1, further comprising: heating the electrode sheet, or the solid electrolyte membrane, or the electrode sheet and the solid electrolyte membrane by means of a heating mechanism, wherein the heating mechanism is located between the electrode sheet unwinding mechanism and the shaping roller assembly, and/or the heating mechanism is located inside the shaping roller assembly.
The preparation method according to claim 1, wherein the solid electrolyte membrane comprises a first solid electrolyte membrane and a second solid electrolyte membrane, and the first solid electrolyte membrane and the second solid electrolyte membrane are roll-composited on two sides of the electrode sheet by the shaping roller assembly.
The preparation method according to claim 1, wherein the elastic member is a protective film or an adhesive layer, and the protective film is transported through a gap between the shaping roller assembly and the solid electrolyte membrane; the adhesive layer covers around the outside of the shaping roller assembly.
The preparation method according to claim 4, wherein the adhesive layer is a plastic, a rubber, or silicone; the protective film is a polymer film or a non-woven fabric.
The preparation method according to claim 1, wherein the shaping roller assembly comprises a first shaping roller assembly and a second shaping roller assembly, and the elastic member is disposed between at least one of the first shaping roller assembly and the second shaping roller assembly, and the solid electrolyte membrane rolled on the electrode sheet.
The preparation method according to claim 1, wherein the shaping roller assembly comprises a first shaping roller assembly and a second shaping roller assembly, and at least one of the first shaping roller assembly and the second shaping roller assembly constitutes an elastic rolling assembly with the elastic member.
The preparation method according to claim 7, wherein the elastic rolling assembly comprises an elastic roller, the elastic roller is used to contact and roll the solid electrolyte membrane, the elastic roller comprises a rigid roller and an elastic member, and the elastic member covers the outside of the rigid roller.
The preparation method according to claim 8, wherein the elastic rolling assembly comprises a shaping rigid roller, and an elastic roller having a hardness lower than that of the shaping rigid roller.
The preparation method according to claim 2, comprising: conveying the electrode sheet by means of the electrode sheet unwinding mechanism, so that the electrode sheet passes through a gap between the heating mechanism and the shaping roller assembly; preheating the electrode sheet by means of the heating mechanism, to obtain a preheated sheet; and performing roll compositing on the preheated sheet and the solid electrolyte membrane by means of the shaping roller assembly, to prepare the composite electrode sheet.
The preparation method according to claim 2, wherein the heating mechanism comprises a first heating mechanism and a second heating mechanism; the shaping roller assembly comprises a first shaping roller assembly and a second shaping roller assembly; the first heating mechanism is located between the electrode sheet unwinding mechanism and the first shaping roller assembly, and the second heating mechanism is located between the first shaping roller assembly and the second shaping roller assembly.
The preparation method according to claim 11, comprising: conveying the electrode sheet by means of the electrode sheet unwinding mechanism, so that the electrode sheet passes through the first heating mechanism; conveying a first solid electrolyte membrane by means of a first solid electrolyte membrane unwinding mechanism located at one side of the electrode sheet unwinding mechanism, so that the first solid electrolyte membrane passes through the first heating mechanism; heating the electrode sheet and the first solid electrolyte membrane by means of the first heating mechanism; compositing the heated electrode sheet and first solid electrolyte membrane by means of the first shaping roller assembly, to obtain a composite membrane sheet; conveying a second solid electrolyte membrane by means of a second solid electrolyte membrane unwinding mechanism located at the other side of the electrode sheet unwinding mechanism, so that the second solid electrolyte membrane passes through the second heating mechanism; heating the composite membrane sheet and the second solid electrolyte membrane by means of the second heating mechanism; and compositing the heated composite membrane sheet and second solid electrolyte membrane by means of the second shaping roller assembly, to obtain the composite electrode sheet.
The preparation method according to claim 2, wherein the heating mechanism comprises a first heating mechanism and a second heating mechanism; the preparation method comprises: conveying the electrode sheet by means of the electrode sheet unwinding mechanism, so that the electrode sheet passes through a gap between the first heating mechanism and the shaping roller assembly; conveying the solid electrolyte membrane by means of the solid electrolyte membrane unwinding mechanism located at the side of the electrode sheet unwinding mechanism, so that the solid electrolyte membrane passes through the second heating mechanism and the gap between the shaping roller assembly and the electrode sheet; preheating the electrode sheet by means of the first heating mechanism; preheating the solid electrolyte membrane by means of the second heating mechanism; and performing roll compositing on the preheated electrode sheet and solid electrolyte membrane by means of the shaping roller assembly, to prepare the composite electrode sheet.
The preparation method according to any one of claims 11 to 13, wherein the first heating mechanism and the second heating mechanism are separately selected from a heater and/or a heating roller assembly.
The preparation method according to claim 14, wherein the heating roller assembly comprises one or more sets of heating rollers, and each set of heating rollers comprises at least one heating roller.
The preparation method according to claim 15, wherein heating temperatures of the plurality of heating rollers are the same or different, and/or heating times of the plurality of heating rollers are the same or different.
The preparation method according to claim 16, wherein the heating time of the plurality of heating rollers is 2 seconds or more.
The preparation method according to any one of claims 11 to 13, wherein heating temperatures of the first heating mechanism and the second heating mechanism are the same or different, and/or heating times of the first heating mechanism and the second heating mechanism are the same or different.
The preparation method according to claim 18, wherein the heating time of the first heating mechanism and the second heating mechanism is 2 seconds or more.
The preparation method according to claim 2, wherein the heating mechanism is located between the electrode sheet unwinding mechanism and the shaping roller assembly, and is used to preheat the electrode sheet, the solid electrolyte membrane and the elastic member, wherein the elastic member is a protective film, and the protective film is transported through a gap between the shaping roller assembly and the solid electrolyte membrane.

Description

RELATED APPLICATIONS The present application claims the priority of Chinese Patent Application No. 2023107610426, entitled "PREPARATION METHOD AND PREPARATION APPARATUS FOR COMPOSITE ELECTRODE SHEET, AND LITHIUM-ION BATTERY," filed on June 27, 2023; the priority of Chinese Patent Application No. 202321841019X, entitled "PREPARATION APPARATUS FOR COMPOSITE ELECTRODE SHEET, AND COMPOSITE ELECTRODE SHEET," filed on July 13, 2023; the priority of Chinese Patent Application No. 2023108476621, entitled "COMPOSITE ELECTRODE SHEET AND PREPARATION METHOD THEREFOR, AND LITHIUM-ION BATTERY," filed on July 12, 2023; the priority of Chinese Patent Application No. 2023108596479, entitled "COMPOSITE ELECTRODE SHEET AND PREPARATION METHOD THEREFOR, AND LITHIUM-ION BATTERY," filed on July 13, 2023; the priority of Chinese Patent Application No. 202321843129X, entitled "COMPOSITE ELECTRODE SHEET AND PREPARATION APPARATUS THEREFOR, AND LITHIUM-ION BATTERY," filed on July 13, 2023; the priority of Chinese Patent Application No. 2023109593675, entitled "COMPOSITE ELECTRODE SHEET AND PREPARATION METHOD THEREFOR, AND LITHIUM-ION BATTERY," filed on August 1, 2023; the priority of Chinese Patent Application No. 2023109318786, entitled "COMPOSITE ELECTRODE SHEET AND PREPARATION METHOD THEREFOR, AND LITHIUM-ION BATTERY," filed on July 27, 2023; the priority of Chinese Patent Application No. 2023109596781, entitled "COMPOSITE ELECTRODE SHEET AND PREPARATION METHOD THEREFOR, AND LITHIUM-ION BATTERY," filed on August 1, 2023; the priority of Chinese Patent Application No. 2023109316367, entitled "PREPARATION METHOD FOR COMPOSITE ELECTRODE SHEET, COMPOSITE ELECTRODE SHEET, AND SOLID-STATE BATTERY," filed on July 27, 2023; and the priority of Chinese Patent Application No. 2023108177121, entitled "COMPOSITE ELECTRODE SHEET AND PREPARATION METHOD THEREFOR, AND LITHIUM-ION BATTERY," filed on July 5, 2023, which are incorporated herein for reference in their entireties. TECHNICAL FIELD The present application relates to the technical field of batteries, and in particular to a composite electrode sheet and a preparation method therefor, an apparatus for preparing the composite electrode sheet, and a lithium-ion battery including the composite electrode sheet. BACKGROUND Lithium-ion batteries are now mainstream energy storage devices on the market with broad application prospects. As new technologies continue to emerge, requirements for battery performance are also increasing. Conventional liquid batteries that use non-aqueous electrolytes as electrolyte systems have many safety concerns. For example, conventional electrolyte materials are flammable and explosive, and positive electrode materials, especially high-energy-density high-nickel ternary materials, are prone to undesirable side reactions with electrolytes, causing safety issues for batteries, etc. To improve the safety performance of batteries, providing a solid electrolyte layer on an electrode is generally considered to have positive effects. At present, a main method of compositing a solid electrolyte on an electrode surface is to apply a solid electrolyte slurry to the electrode sheet surface by means of coating. This method can be directly embedded into a current mature coating process, but also faces many problems. For example, (1) due to rapid drying and evaporation of a solvent in a drying process after coating, surface tension of an electrode sheet changes rapidly, and the electrode sheet is prone to curling and lifting, and in addition, the rapid evaporation of the solvent causes a crystalline binder to segregate on the electrode sheet surface; (2) some electrolyte materials, such as sulfide solid electrolytes, are extremely sensitive to moisture, and small amounts of moisture present in wet processes can easily corrode the electrolyte materials; (3) some novel binders have compatibility issues with solvents, and new solvents need to be developed to adapt to the novel binders; and (4) wet processes consume a large amount of solvents, resulting in excessively high environmental remediation costs. Therefore, researchers and developers have gradually turned their attention to preparation of composite electrode sheets from an electrode sheet and a solid electrolyte membrane by dry processes, to improve the safety performance of batteries. Currently, methods for preparing electrode sheets by dry processes have been reported, and the proportion of dry-process electrodes in the battery field is increasing year by year. Compared with a dry-process electrode, the difficulty in preparing a composite electrode sheet containing a solid electrolyte membrane by a dry process lies in weak interlayer bonding between a solid electrolyte layer and an electrode layer, and weak mechanical strength of a composite electrode. Dry roll compositing of a multi-layer structure has different technical characteristics from rolling of a single-layer structure. In another aspect, bonding strength between