EP-4738449-A1 - ELECTRODE SHEET AND BATTERY

EP4738449A1EP 4738449 A1EP4738449 A1EP 4738449A1EP-4738449-A1

Abstract

The present invention provides an electrode plate and battery. The electrode plate comprises a current collector and an electrode film provided on at least one functional surface of the current collector, wherein the electrode film comprises fibres, at least some of the fibres extending in a first direction of the electrode plate. By defining the composition and structure of the electrode plate, the tensile force at break and bonding strength of the electrode plate can be significantly improved, the tensile strength of the electrode plate can be increased, and the risk of breakage can be reduced. When the electrode plate is applied to a battery, the cycling performance and thickness expansion rate of the battery can be significantly improved.

Inventors

WANG, Di
CHEN, Tiantian
JIANG, Huan
XIE, Jichun

Assignees

Zhuhai CosMX Battery Co., Ltd.

Dates

Publication Date: 20260506
Application Date: 20241009

Claims (20)

An electrode plate, comprising a current collector and an electrode film provided on at least one functional surface of the current collector, wherein the electrode film comprises fibres, at least some of the fibres extending in a first direction of the electrode plate.
The electrode plate according to claim 1, wherein an included angle between the extension direction of the fibres and a first direction of the electrode plate ranges from 0-30°.
The electrode plate according to claim 1, wherein the tensile force at break of the electrode plate in the first direction is greater than or equal to the tensile force at break of the electrode plate in a second direction; and the second direction is perpendicular to the first direction.
The electrode plate according to claim 1, wherein the ratio of the tensile force at break of the electrode plate in the first direction to the tensile force at break of the electrode plate in the second direction is (1-2) : 1, preferably (1.02-1.52) : 1.
The electrode plate according to claim 1, wherein the ratio of the tensile force at break of the electrode plate in the first direction to the thickness of the electrode plate is (0.008-0.1) : 1, wherein the tensile force at break of the electrode plate in the first direction is in kgf, and the thickness of the electrode plate is in µm.
The electrode plate according to any one of claims 1-5, wherein the tensile force at break of the electrode plate in the first direction is 3-6 kgf; and/or the tensile force at break of the electrode plate in the second direction is 2-5.5 kgf; and/or the thickness of the electrode plate is 65-350 µm.
The electrode plate according to any one of claims 1-5, wherein the tensile force at break of the current collector in the second direction is less than the tensile force at break of the current collector in the first direction.
The electrode plate according to claim 7, wherein the ratio of the tensile force at break of the current collector in the first direction to the tensile force at break of the current collector in the second direction is (0.67-2.75) : 1, preferably (0.875-1.67) : 1.
The electrode plate according to any one of claims 1-5, wherein the electrode film further comprises active material bodies, wherein at least some of the fibres have a size in the first direction that is greater than the median particle size of the active material bodies.
The electrode plate according to claim 9, wherein the active material bodies comprise LiCoO 2 , LiMn 2 O 4 , LiMnO 2 , LiNiO 2 , LiFePO 4 , LiMnPO 4 , LiCo x Ni 1-x O 2 , and LiCo x Ni 1-x-y Al y O 2 , where 0 ≤ x ≤ 1, and 0 ≤ y ≤ 1, or the active material bodies comprise at least one of artificial graphite, natural graphite, soft carbon, hard carbon, mesocarbon microbeads, Si, SiO x , Si-C, and SiO x -C.
The electrode plate according to claim 9, wherein the ratio of the size of individual fibres in the first direction to the median particle size of the active material bodies is 1 : (1-4000), preferably 1 : (1-400).
The electrode plate according to claim 11, wherein the size of individual fibres in the first direction is 250 nm-1 mm; and/or the median particle size of the active material bodies is 250 nm-30 µm.
The electrode plate according to any one of claims 1-5, wherein in the thickness direction of the electrode plate, the fibres extend in the thickness direction of the electrode plate.
The electrode plate according to claim 1, wherein in the thickness direction of the electrode plate, adjacent active material bodies are connected to each other by the fibres.
The electrode plate according to claim 1, wherein the electrode plate further comprises an adhesive layer, the adhesive layer being located between the current collector and the electrode film.
The electrode plate according to claim 15, wherein the adhesive layer comprises a binder and a conductive agent, the binder comprises at least one of polyvinylidene fluoride, a styrene-butadiene rubber, an EVA hot-melt adhesive, a TPR hot-melt adhesive, a polyolefin hot-melt adhesive, a polyamide hot-melt adhesive, a polyester hot-melt adhesive, a polyethylene hot-melt adhesive and a polyester amide hot-melt adhesive, and/or the conductive agent comprises at least one of conductive carbon black, carbon nanotubes, and graphene.
The electrode plate according to claim 1, wherein the fibres comprise at least one of fibrous polytetrafluoroethylene, polyvinylidene fluoride, an ethylene-tetrafluoroethylene copolymer, a fluorinated ethylene-propylene copolymer, polyvinylpyrrolidone, polyethylene oxide, carboxymethyl cellulose, styrene-butadiene rubber, polyacrylic acid, a hot-melt adhesive, and polyethylene.
The electrode plate according to any one of claims 1-4, wherein that the electrode film further comprises recesses, wherein the recesses are located on a surface of the side of the electrode film away from the current collector, and/or the recesses are located inside the electrode film.
The electrode plate according to claim 18, wherein the recess is filled with a lithium-containing compound; wherein the lithium-containing compound comprises at least one of lithium oxide, lithium carbonate, and lithium fluoride.
A battery, comprising the electrode plate according to any one of claims 1-19.

Description

The present application claims the priority to Chinese Patent Application No. 202311773277.3, filed with the China National Intellectual Property Administration on December 21, 2023 and entitled "ELECTRODE PLATE AND BATTERY", which is incorporated herein by reference in its entirety. TECHNICAL FIELD The present application relates to an electrode plate and battery, belonging to the technical field of lithium-ion batteries. BACKGROUND Lithium-ion batteries are widely used in fields such as electronics, communications and electric vehicles due to the advantages such as a high energy utilization efficiency, a wide operating temperature range and environmental friendliness. As an important component of a lithium-ion battery, an electrode plate has a critical impact on the performance of the lithium-ion battery. At present, the electrode plate is often prepared by a wet process, which involves preparing a slurry with an organic solvent, followed by coating, drying and rolling to obtain the electrode plate. However, organic solvents are prone to causing pollution, and subsequently, the solvents need to be dried and removed, resulting in significant energy waste and increasing production costs. Moreover, the electrode plate is prone to suffer from cracking, poor toughness, delamination, etc., making it impossible to further improve the energy density. At present, in order to improve the energy density of the battery, reduce the energy consumption during the preparation of the electrode, and reduce the production costs, most electrodes are prepared by dry electrode processes. Compared with wet processes, the dry electrode processes place higher demands on the working pressure, rolling accuracy and uniformity of a rolling device, and require a greater compaction force, which leads to problems such as breakage and powder detachment that are prone to occur during the rolling process. Therefore, how to improve the tensile force at break of the electrode plate and reduce the risk of breakage during the rolling process, is the technical problem to be solved urgently in the art. SUMMARY The present invention provides an electrode plate. By defining the composition and structure of the electrode plate, the tensile force at break and bonding strength of the electrode plate can be significantly improved, the tensile strength of the electrode plate can be increased, and the risk of breakage can be reduced. The electrode plate can be applied directly to a battery, and can significantly improve the cycling performance and thickness expansion rate of the battery. The present invention further provides a battery which has excellent cycling performance, thickness expansion rate, etc., due to the inclusion of the above electrode plate. In a first aspect of the present invention, provided is an electrode plate comprising a current collector, and an electrode film provided on at least one functional surface of the current collector, wherein the electrode film comprises fibres, at least some of the fibres extending in a first direction of the electrode plate. The electrode plate as described above, wherein an included angle between the extension direction of the fibres and the first direction of the electrode plate ranges from 0-30°. The electrode plate as described above, wherein the tensile force at break of the electrode plate in the first direction is greater than or equal to the tensile force at break of the electrode plate in a second direction; and the second direction is perpendicular to the first direction. The electrode plate as described above, wherein the ratio of the tensile force at break of the electrode plate in the first direction to the tensile force at break of the electrode plate in the second direction is (1-2) : 1, preferably (1.02-1.52) : 1. The electrode plate as described above, wherein the ratio of the tensile force at break of the electrode plate in the first direction to the thickness of the electrode plate is (0.008-0.1) : 1; wherein the tensile force at break of the electrode plate in the first direction is in kgf, and the thickness of the electrode plate is in µm. The electrode plate as described above, wherein the tensile force at break of the electrode plate in the first direction is 3-6 kgf; and/or the tensile force at break of the electrode plate in the second direction is 2-5.5 kgf; and/orthe thickness of the electrode plate is 65-350 µm. The electrode plate as described above, wherein the tensile force at break of the current collector in the second direction is less than the tensile force at break of the current collector in the first direction. The electrode plate as described above, wherein the ratio of the tensile force at break of the current collector in the first direction to the tensile force at break of the current collector in the second direction is (0.67-2.75) : 1, preferably (0.875-1.67) : 1. The electrode plate as described above, wherein the electrode film further comprises active ma