CN-114744139-B - Lithium battery pole piece and preparation process thereof

CN114744139BCN 114744139 BCN114744139 BCN 114744139BCN-114744139-B

Abstract

The invention provides a lithium battery pole piece and a preparation process thereof, and relates to the technical field of lithium batteries, a coating layer is coated at the center of at least one surface of a current collector, an edge coating layer is coated on two sides of at least one surface of the current collector, the positions, connected with the current collector, of the two sides of the coating layer are covered by 0.1-10 mm, a covering layer is formed in a superposition area of the edge coating layer and the coating layer, a chemically crosslinked water-insoluble polymer, N-methylpyrrolidone or deionized water and a coloring material are selected from fluoroplastic, polyvinylidene fluoride (PVDF), polyvinyl chloride (PVF) and an insulating edge coating, the chemically crosslinked water-insoluble polymer is more flexible than the traditional boehmite edge coating layer, the tensile resistance of the current collector can be improved, and dust generated in the production process of the insulating edge coating is less.

Inventors

GE ZHIMIN
TU XIAOLONG
XIAO QIFEI
GAO RUN
HU YANLAN
DENG WEN
LIU ZHENJUN
CHEN JINLONG
TAO QIONGCHENG
HUANG MING
LI YUAN
TANG JIAOJUN
TANG XIAOWEI

Assignees

江西赣锋锂电科技股份有限公司

Dates

Publication Date: 20260512
Application Date: 20220313

Claims (7)

1. The preparation process of the lithium battery pole piece is characterized in that the lithium battery pole piece comprises the following steps: A current collector, a coating layer and an edge coating layer with an insulating glue material; A coating layer coated on the center of at least one surface of the current collector; an edge coating layer coated on both sides of at least one surface of the current collector; the edge coating covers the positions of 0.1mm-10mm at which the two sides of the coating layer are connected with the current collector, and the overlapping area of the edge coating and the coating layer forms a cover layer; The current collector comprises two layers of base materials which are arranged up and down and a composite layer which is arranged between the base materials, wherein the composite layer is an interlayer between the two layers of base materials, and the base materials are bonded with the composite layer through an adhesive; the preparation process of the lithium battery pole piece comprises the following steps: S1, preparing a current collector; s2, preparing coating layer slurry and side coating layer slurry; s3, coating the prepared coating layer slurry and the side coating layer slurry on the surface of the current collector through coating equipment; the step S1 comprises the following steps: S11, firstly, primarily attaching two base materials to a composite layer by using an adhesive, wherein the base materials are aluminum foils or copper foils, when the aluminum foils are selected, the base materials are used as positive current collectors, and when the copper foils are selected, the base materials are used as negative current collectors; S12, compacting the current collector obtained by the lamination in the step S1 through external pressure, wherein a pressure source is rolled or punched or compacted to obtain a composite current collector pole piece; s13, punching a through hole on the surface of the current collector pole piece, wherein the punching mode comprises punching, stamping or drilling, the through hole penetrates through the base material and the composite layer, the punched base material is locally broken and deformed into the through hole under the influence of the compliance force of the punching to form a tubular shape, and the tail end of the extending part of the base material extends to the other layer of base material to form a welding point; and S14, spot welding the welding spot on the edge of the through hole position in the other layer of base material by adopting a vacuum plating or laser lattice welding mode, and finishing the welding between the two layers of base materials, wherein the vacuum plating mode comprises magnetron sputtering, vacuum evaporation and ion plating.
2. The process for preparing the lithium battery pole piece according to claim 1, wherein the process comprises the following steps: the overcoat material includes a chemically crosslinked water insoluble polymer, N-methylpyrrolidone, and a colorant.
3. The process for preparing the lithium battery pole piece according to claim 2, wherein the process comprises the following steps: The coloring material comprises one or more of carbon black, cobalt blue, ultramarine, ferric oxide, cadmium red, chrome orange, molybdenum orange, cadmium yellow, chrome yellow, nickel titanium yellow, titanium white, lithopone, zinc white, phthalocyanine pigment, azo pigment, anthraquinone pigment, indigo pigment and metal complex pigment.
4. The process for preparing the lithium battery pole piece according to claim 1, wherein the process comprises the following steps: the thickness of the side coating is 1-30 μm, and the width of the covering layer is 0.1-2 mm.
5. The process for preparing the lithium battery pole piece according to claim 1, wherein the process comprises the following steps: And two sides of the current collector are cut into a plurality of tabs through a die cutting device, the edge coating extends to the root position of the tab by 1-30 mu m, and a traction part is formed at the position of the edge coating extending to the tab.
6. The process for preparing the lithium battery pole piece according to claim 1, wherein the process comprises the following steps: the current collector further comprises a supporting layer arranged between the current collector and the coating layer, wherein the supporting layer is at least one of conductive carbon materials and metal materials, the conductive carbon materials comprise zero-dimensional conductive carbon, one-dimensional conductive carbon comprises conductive carbon black, one-dimensional conductive carbon comprises carbon nanotubes, two-dimensional conductive carbon comprises conductive graphite and graphene, three-dimensional conductive carbon comprises at least one of reduced graphene oxide, and the metal materials comprise at least one of aluminum powder, iron powder and silver powder.
7. A lithium battery pole piece, characterized in that the pole piece is prepared by adopting the preparation process of the lithium battery pole piece according to any one of claims 1-6.

Description

Lithium battery pole piece and preparation process thereof Technical Field The invention relates to the technical field of lithium batteries, in particular to a lithium battery pole piece and a preparation process thereof. Background The existing lithium ion battery pole piece mainly comprises a current collecting carrier, an active material layer and an edge functional layer. In general, the positive electrode uses aluminum foil or carbon-coated aluminum foil as a current collector, and the negative electrode uses copper foil as a current collector. The edge reinforcing layer is coated on the edge of the pole piece of the lithium ion battery, so that the pressure resistance of the pole piece can be enhanced, and the short circuit risk can be reduced. However, the traditional edge coating has poor tensile toughness, and more dust, burrs or beads are easily generated in the edge processing process, so that serious potential safety hazards exist in subsequent cell production and application. Disclosure of Invention The invention aims to solve the technical problems that the traditional edge coating has poor tensile toughness, more dust, burrs or beads are easy to generate in the edge processing process, and the lithium battery pole piece is provided for solving the problems existing in the prior art. In order to solve the problems in the prior art, the invention discloses a lithium battery pole piece, which comprises a current collector, a coating layer and an edge coating layer with an insulating adhesive material; A coating layer coated on the center of at least one surface of the current collector; specifically, the coating mode of the coating layer is continuous or intermittent. As an improvement of the safety battery pole piece, the invention further comprises an edge coating: an edge coating layer coated on both sides of at least one surface of the current collector; Specifically, the side coating material is selected from chemically crosslinked water insoluble polymer, N-methyl pyrrolidone or deionized water, and coloring material; further, the chemically crosslinked water-insoluble polymer is selected from one or more of fluoroplastic, polyvinylidene fluoride (PVDF), polyvinyl chloride (PVF), polytetrafluoroethylene (PTFE), polytetrafluoroethylene (FRP), soluble Polytetrafluoroethylene (PFA), polytrifluoroethylene (PCTFE), ethylene chlorotrifluoroethylene copolymer (ECTFE), ethylene-tetrachloroethylene copolymer (ETFE), polyimide resin (PI), cyclic Olefin Copolymer (COC), polyacrylic or styrene-butadiene rubber or polyamide or parylene, derivatives thereof, crosslinked products thereof, and copolymers thereof; Still further, the colorant is selected from one or more of carbon black, cobalt blue, ultramarine, ferric oxide, cadmium red, chrome orange, molybdenum orange, cadmium yellow, chrome yellow, nickel titanium yellow, titanium white, lithopone, zinc white, phthalocyanine pigment, azo pigment, anthraquinone pigment, indigo pigment and metal complex pigment; the preparation method of the edge coating in the safe battery pole piece specifically comprises the following steps: S1, glue preparation Taking a chemically crosslinked water-insoluble polymer, N-methyl pyrrolidone or deionized water and a coloring material, wherein the chemically crosslinked water-insoluble polymer is exemplified by fluoroplastic, the fluoroplastic is 5-30%, the N-methyl pyrrolidone or deionized water is 70-95%, placing the prepared material into a stirrer at room temperature under a high dew point environment, stirring to prepare glue, and stirring for 2H-4H to obtain the insulating glue; s2, coloring the insulating edge coating After the stirring time is over, proportioning 0.2% -1% of coloring material, adding the coloring material into a stirrer to blend with the insulating-edge gluing obtained in the step S1, stirring for 2H-4 h again, and after the stirring time is over, obtaining the colored insulating-edge gluing; According to the design, the colored insulating side coating is coated on two sides of the current collector by using coating equipment to form the side coating, the pure colloidal side coating has stretching resistance compared with the traditional boehmite edge coating, and less dust is generated in the production process, so that the maintenance of the production environment is facilitated, the side coating position of the current collector is smoother, burrs and beads are not easy to appear, and the coloring material has the main functions of enabling the insulating side coating to develop color, and facilitating the identification of the side coating position in the subsequent lithium battery processing section; further, the edge coating of the insulating adhesive material can greatly reduce the breakage rate of the pole piece in the process of post-transmission and rolling of the pole piece. The positions, connected with the current collectors, of the two sides of the coating layer are covered by the s