Polymer current collector, preparation method thereof, and secondary battery, battery module, battery pack, and apparatus associated therewith

Patent metadata

Field	Value
Publication number	US-2022367877-A1
Application number	US-202217810644-A
Country	US
Kind code	A1
Filing date	Jul 5, 2022
Priority date	Aug 7, 2020
Publication date	Nov 17, 2022
Grant date	—

Abstract

This application provides a polymer current collector, a preparation method thereof, and a secondary battery, battery module, battery pack, and apparatus associated therewith. The polymer current collector provided in this application includes polymer film layers, where the polymer film layers include a first polymer film layer and a second polymer film layer, a resistivity of the first polymer film layer is denoted as ρ1, a resistivity of the second polymer film layer is denoted as ρ2, and the current collector satisfies ρ1>ρ2. The polymer current collector in this application can induce to deposit of lithium metal from a low conductivity side to a high conductivity side, avoiding risks of depositing lithium ions on the surface of the current collector and thereby increasing cycle life of lithium metal batteries.

First claim

1 . A polymer current collector, comprising polymer film layers, wherein the polymer film layers comprise a first polymer film layer and a second polymer film layer, a resistivity of the first polymer film layer is denoted as ρ1, a resistivity of the second polymer film layer is denoted as ρ2, and ρ1>ρ2.

2 . The polymer current collector according to claim 1 , wherein ρ1/ρ2>40.

3 . The polymer current collector according to claim 2 , wherein
10 2 Ω·cm≤ρ1≤10 9 Ω·cm, and preferably, 10 3 Ω·cm≤ρ1≤10 6 Ω·cm; and/or 10 Ω·cm≤ρ2≤10 4 Ω·cm, and preferably, 10 Ω·cm≤ρ2≤1000 Ω·cm.

4 . The polymer current collector according to claim 1 , wherein in the first polymer film layer, a variation of C/N is 0.1 to 10, and preferably, 0.2 to 3; and/or
in the first polymer film layer, a variation of C/O is 0.1 to 10, and preferably, 0.2 to 3.

5 . The polymer current collector according to claim 1 , wherein
in the second polymer film layer, a variation of C/N is 0.1 to 15, and preferably, 0.2 to 5; and/or in the second polymer film layer, a variation of C/O is 0.1 to 15, and preferably, 0.2 to 5.

6 . The polymer current collector according to claim 1 , wherein a quantity of the polymer film layers is greater than 2.

7 . The polymer current collector according to claim 1 , wherein the polymer current collector further comprises a third polymer film layer, the second polymer film layer is disposed between the third polymer film layer and the first polymer film layer, a resistivity of the third polymer film layer is denoted as ρ3, and the current collector further satisfies ρ2>ρ3.

8 . The polymer current collector according to claim 7 , wherein the polymer current collector further satisfies one or more of the following conditions:
(1) 20≤ρ2/ρ3≤1000; (2) 1≤ρ3≤500 Ω·cm; (3) in the third polymer film layer, a variation of C/N is 0.3 to 20; and (4) in the third polymer film layer, a variation of C/O is 0.3 to 20.

9 . The polymer current collector according to claim 8 , wherein
thickness of the first polymer film layer is greater than or equal to 1 μm; thickness of the second polymer film layer is greater than or equal to 1 μm; and/or thickness of the third polymer film layer is greater than or equal to 1 μm.

10 . The polymer current collector according to claim 1 , wherein the polymer current collector is a porous structure.

11 . A preparation method of the polymer current collector according to claim 1 , comprising the following steps:
S1: providing two or more than two polymer films having different resistivities; and S2: pressing the polymer films in Si in descending or ascending order of resistivities to obtain the polymer current collector; wherein the polymer current collector comprises polymer film layers, the polymer film layers comprise a first polymer film layer and a second polymer film layer, a resistivity of the first polymer film layer is denoted as ρ1, a resistivity of the second polymer film layer is denoted as ρ2, and the current collector satisfies ρ1>ρ2.

12 . The preparation method according to claim 11 , wherein a preparation method of the polymer films comprises the following steps:
(1) providing two or more than two polymer film precursors comprising a same polymer raw material; and (2) subjecting the polymer film precursors in (1) to sintering, wherein the polymer film precursors each are sintered at different temperatures to obtain polymer films having different resistivities.

13 . The preparation method according to claim 12 , wherein the sintering temperature is 200 degree Celsius (° C.) to 2000° C.

14 . The preparation method according to claim 13 , wherein the polymer raw material comprises one or more of nitrile polymer, alcohol polymer, cellulose polymer, sulfone polymer, amine polymer, ester polymer, ketone polymer, melamine foam, and cotton fiber; and preferably, the polymer raw material comprises one or more of polyacrylonitrile, polyvinyl alcohol, carboxymethyl cellulose, and polysulfuriamide.

15 . A secondary battery, comprising a negative electrode plate, wherein the negative electrode plate comprises the polymer current collector according to claim 1 .

16 . The secondary battery according to claim 15 , wherein the secondary battery further comprises a separator, and the first polymer film layer is closer to the separator than the second polymer film layer.

17 . The secondary battery according to claim 16 , wherein the secondary battery is an alkali metal secondary battery, and preferably, a lithium metal secondary battery, a potassium metal secondary battery, or a sodium secondary battery.

18 . An apparatus, comprising at least one of the secondary battery according to claim 15 .

Assignees

• Contemporary Amperex Technology Co Ltd

Inventors

• Fu Ang
• Liu Chengyong
• Guo Yongsheng
• Fu Jiawei
• Li Qian
• Hu Bobing
• Huang Shengyuan

Classifications

• H01M10/052

  Li-accumulators · CPC title

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M4/667 Primary

  in the form of layers, e.g. coatings · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• H01M4/801

  Sintered carriers · CPC title