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CN-121983579-A - Current collector, preparation method thereof, electrode and lithium ion battery

CN121983579ACN 121983579 ACN121983579 ACN 121983579ACN-121983579-A

Abstract

The invention relates to the technical field of lithium ion batteries, and discloses a current collector, a preparation method thereof, an electrode and a lithium ion battery. The current collector comprises a basal layer, a functional layer and a coating layer, wherein the functional layer is arranged between the basal layer and the coating layer, the basal layer is made of insulating materials, the functional layer is of a composite layer structure and comprises metal layers and metal oxide layers which are alternately arranged, and the coating layer is a solid electrolyte layer. The current collector adopts a functional layer structure with alternating metal layers and metal oxide layers, can improve the thermal stability and safety of the battery under extreme conditions, and has excellent performances in needling, extrusion and short circuit testing, thereby effectively avoiding thermal runaway.

Inventors

  • CHEN FEIFAN
  • WANG KAI

Assignees

  • 江苏睿恩新能源科技有限公司

Dates

Publication Date
20260505
Application Date
20260119

Claims (10)

  1. 1. A current collector, comprising: The basal layer is made of insulating materials; The functional layer is of a composite layer structure and comprises metal layers and metal oxide layers which are alternately arranged; the coating layer is a solid electrolyte layer; The functional layer is disposed between the base layer and the cladding layer.
  2. 2. The current collector of claim 1, wherein the current collector comprises a plurality of metal layers, The functional layer is composed of a plurality of metal layers, and the metal oxide layers are arranged between the adjacent metal layers in a sandwiched mode.
  3. 3. The current collector of claim 2, wherein the current collector comprises a plurality of metal layers, The thickness ratio of the metal layer to the metal oxide layer is set to 7-10:1.
  4. 4. A current collector according to any one of claim 1 to 3, The thickness ratio of the base layer, the functional layer and the coating layer is set to 2-6:0.5-3:0.5-2.
  5. 5. The current collector of claim 4, wherein the current collector comprises, A bonding transition layer is arranged between the basal layer and the functional layer; and/or the insulating material is selected from one or more of polyethylene terephthalate, polypropylene and polyimide.
  6. 6. The current collector of claim 5, wherein the current collector comprises, The solid electrolyte layer is formed by mixing an organic matrix and an inorganic fast ion conductor, wherein the mass ratio of the organic matrix to the inorganic fast ion conductor is 4:1-1:4, the organic matrix is one or more selected from polyethylene oxide, polyacrylonitrile and polyvinylidene fluoride, and the inorganic fast ion conductor is one or more selected from lithium aluminum germanium phosphate, lithium lanthanum zirconium oxide and lithium lanthanum titanium oxide.
  7. 7. A current collector according to any one of claim 1 to 3, The functional layer and the coating layer are respectively provided with two layers which are respectively arranged on two sides of the basal layer.
  8. 8. A method of preparing a current collector according to any one of claims 1 to 7, comprising the steps of: s1, evaporating the material of the metal layer to enable the material to be deposited on the side surface of the substrate layer; s2, oxidizing the outer surface of the metal layer to obtain the metal oxide layer; S3, evaporating the material of the metal layer, and depositing on the outer surface of the metal oxide layer, and repeating the step S2 to obtain the functional layer; and S4, spraying the slurry of the solid electrolyte layer on the outer surface of the functional layer.
  9. 9. An electrode comprising a current collector according to any one of claims 1 to 7, or a current collector obtainable by a method according to claim 7.
  10. 10. A lithium ion battery, characterized by comprising the current collector of any one of claims 1 to 7, or the current collector obtained by the preparation method of claim 8, or the electrode of claim 9, wherein the lithium ion battery comprises lithium iron phosphate, lithium manganese iron phosphate or a ternary battery system, and the ternary battery system is made of the following materials LiNi x Co y Mn z M b O 2 ,0.7≤x≤0.9,0.1≤y≤0.3,0.1≤z≤0.3,0≤b≤0.25,x+y+z+b=1.

Description

Current collector, preparation method thereof, electrode and lithium ion battery Technical Field The invention relates to the technical field of lithium ion batteries, in particular to a current collector, a preparation method thereof, an electrode and a lithium ion battery. Background With the wide application of lithium ion batteries in electric automobiles, portable electronic equipment and energy storage systems, the improvement of the energy density of the lithium ion batteries provides a larger space for improving the battery endurance. However, when a high energy density battery is subjected to mechanical impact, internal short circuits are liable to occur, resulting in thermal runaway, which seriously affects the safety of the lithium ion battery. Especially, when the lithium ion battery is mechanically damaged by needling, the internal short circuit can cause a large amount of heat to be released, and fire or explosion can be caused. Therefore, improving the safety of lithium ion batteries, especially under extreme conditions such as needling test, has become a technical problem to be solved. In the conventional lithium ion battery, a current collector is mostly a metal current collector such as aluminum or copper, and although the metal material has higher conductivity, a path of a short circuit cannot be effectively isolated when the metal current collector is subjected to mechanical deformation, so that the risk of thermal runaway is increased. It should be noted that the information disclosed in the above background section is only for enhancing understanding of the background of the invention and thus may include information that does not form the prior art that is already known to those of ordinary skill in the art. Disclosure of Invention The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosed embodiments. This summary is not an extensive overview nor is intended to identify key/critical elements or to delineate the scope of such embodiments, but is intended as a prelude to the more detailed description that follows. Aiming at the problem that the prior art is single, the embodiment of the invention enriches the solution, and provides a current collector, a preparation method thereof, an electrode and a lithium ion battery, so as to solve the problem that the prior metal current collector is relatively high in risk of thermal runaway particularly when suffering mechanical deformation. The corresponding problems are solved by improving the complex coordination of the technical means such as short circuit path isolation, optimizing the heat diffusion or heat conduction performance and the like. In some embodiments, a current collector comprises: The basal layer is made of insulating materials; The functional layer is of a composite layer structure and comprises metal layers and metal oxide layers which are alternately arranged; the coating layer is a solid electrolyte layer; The functional layer is disposed between the base layer and the cladding layer. In some embodiments, the functional layer is composed of a plurality of the metal layers with the metal oxide layer interposed between adjacent ones of the metal layers. In some embodiments, the thickness ratio of the metal layer to the metal oxide layer is set to 7-10:1. In some embodiments, the thickness ratio of the base layer, the functional layer, and the cladding layer is set to 2-6:0.5-3:0.5-2. In some embodiments, an adhesive transition layer is disposed between the base layer and the functional layer, and/or the insulating material is selected from one or more of polyethylene terephthalate, polypropylene, polyimide, and combinations thereof. In some embodiments, the solid electrolyte layer is made of a mixture of an organic matrix and an inorganic fast ion conductor, wherein the mass ratio of the organic matrix to the inorganic fast ion conductor is 4:1-1:4, the organic matrix is one or more selected from polyethylene oxide, polyacrylonitrile and polyvinylidene fluoride, and the inorganic fast ion conductor is one or more selected from lithium aluminum germanium phosphate, lithium lanthanum zirconium oxide and lithium lanthanum titanium oxide. In some embodiments, the functional layer and the coating layer are both provided with two layers, which are respectively arranged at two sides of the substrate layer. In some embodiments, a method of preparing a current collector as described above, comprising the steps of: s1, evaporating the material of the metal layer to enable the material to be deposited on the side surface of the substrate layer; s2, oxidizing the outer surface of the metal layer to obtain the metal oxide layer; S3, evaporating the material of the metal layer, and depositing on the outer surface of the metal oxide layer, and repeating the step S2 to obtain the functional layer; and S4, spraying the slurry of the solid electrolyte layer on the outer surface of t