Positive electrode sheet containing high-safety heat-sensitive coating and lithium-ion battery

Patent metadata

Field	Value
Publication number	US-12555797-B2
Application number	US-202218059192-A
Country	US
Kind code	B2
Filing date	Nov 28, 2022
Priority date	May 29, 2020
Publication date	Feb 17, 2026
Grant date	Feb 17, 2026

Abstract

A positive electrode sheet containing a high-safety heat-sensitive coating and a lithium-ion battery containing the positive electrode sheet are provided. The heat-sensitive coating includes a first conductive agent, a first binder, heat-sensitive polymer microspheres and an auxiliary agent, and has a conductive property at normal temperature and also has advantages of increasing a contact area between an active material and a current collector, improving the conductivity, and effectively reducing the polarization of battery and the like; when the use temperature of the positive electrode sheet reaches 120° C. and above, the heat-sensitive polymer microspheres will melt to form a plurality of continuous electron blocking layers, current blocking occurs in the coating, an internal blocking forms inside the battery, thereby preventing the occurrence of further thermal runaway of lithium-ion battery.

First claim

What is claimed is:

1 . A positive electrode sheet, comprising a positive current collector, a heat-sensitive coating, a composite fusion layer, and a positive active material layer, wherein the heat-sensitive coating, the composite fusion layer, and the positive active material layer are sequentially arranged on a surface of the positive current collector;
the heat-sensitive coating comprises heat-sensitive polymer microspheres, a first conductive agent, a first binder and an auxiliary agent; the positive active material layer comprises a positive active material, a second conductive agent and a second binder; a thickness of the composite fusion layer is 0.001-0.5 μm; the composite fusion layer comprises the positive active material, the heat-sensitive polymer microspheres, the first conductive agent, the first binder, the second conductive agent, the second binder, and the auxiliary agent; a particle size of the heat-sensitive polymer microsphere is 100 nm-3.0 μm; and a separator resistance of the positive electrode sheet is less than 10Ω wherein a use temperature of the positive electrode sheet reaches a heat-sensitive temperature and above, the heat-sensitive polymer microspheres are melted to form a plurality of continuous electron blocking layers, the morphology of the heat sensitive polymer microspheres changes and current blocking occurs in the heat sensitive coating, forming an internal blocking inside a secondary battery, preventing the occurrence of further thermal runaway of the secondary battery.

2 . The positive electrode sheet according to claim 1 , wherein the heat-sensitive coating comprises the following components by weight percentage: 1.1-95 wt % of the heat-sensitive polymer microspheres, 2.9-48.9 wt % of the first conductive agent, 2-40 wt % of the first binder and 0.1-10 wt % of the auxiliary agent.

3 . The positive electrode sheet according to claim 1 , wherein the positive active material layer comprises the following components by weight percentage: 80-99 wt % of the positive active material, 0.5-10 wt % of the second conductive agent and 0.5-10 wt % of the second binder.

4 . The positive electrode sheet according to claim 2 , wherein the positive active material layer comprises the following components by weight percentage: 80-99 wt % of the positive active material, 0.5-10 wt % of the second conductive agent and 0.5-10 wt % of the second binder.

5 . The positive electrode sheet according to claim 2 , wherein a thickness of the current collector is 0.1 μm-20 μm; and/or a thickness of the heat-sensitive coating is 0.1 μm-5 μm; and/or a thickness of the positive active material layer is 5-100 μm.

6 . The positive electrode sheet according to claim 3 , wherein a thickness of the current collector is 0.1 μm-20 μm; and/or a thickness of the heat-sensitive coating is 0.1 μm-5 μm; and/or a thickness of the positive active material layer is 5-100 μm.

7 . The positive electrode sheet according to claim 1 , wherein a heat-sensitive temperature of the heat-sensitive polymer microsphere is 115° C.-160° C.

8 . The positive electrode sheet according to claim 2 , wherein a heat-sensitive temperature of the heat-sensitive polymer microsphere is 115° C.-160° C.

9 . The positive electrode sheet according to claim 1 , wherein the heat-sensitive polymer microsphere is selected from at least one of polyethylene, polypropylene, polyamide, polyester amide, polystyrene, polyvinyl chloride, polyester, polyurethane, olefin copolymer or copolymer modified by monomer thereof.

10 . The positive electrode sheet according to claim 2 , wherein the heat-sensitive polymer microsphere is selected from at least one of polyethylene, polypropylene, polyamide, polyester amide, polystyrene, polyvinyl chloride, polyester, polyurethane, olefin copolymer or copolymer modified by monomer thereof.

11 . The positive electrode sheet according to claim 1 , wherein in the heat-sensitive coating, the heat-sensitive polymer microspheres account for 1.1-95 vol % of a total volume of the heat-sensitive coating.

12 . The positive electrode sheet according to claim 2 , wherein in the heat-sensitive coating, the heat-sensitive polymer microspheres account for 1.1-95 vol % of a total volume of the heat-sensitive coating.

13 . A secondary battery, comprising the positive electrode sheet according to claim 1 .

Assignees

• Zhuhai Cosmx Battery Co Ltd

Inventors

• Tang Weichao
• Li Suli
• Zhao Wei
• Chen Ruofan
• Liu Chunyang
• Li Junyi
• Xu Yanming

Classifications

• H01M4/139

  Processes of manufacture · CPC title

• H01M50/586

  inside the batteries, e.g. incorrect connections of electrodes · CPC title

• H01M50/581

  in response to temperature · CPC title

• H01M4/13

  Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof · CPC title

• H01M4/36

  Selection of substances as active materials, active masses, active liquids · CPC title