Electrolyte, secondary battery, battery module, battery pack, and power consuming device

Patent metadata

Field	Value
Publication number	US-12418047-B2
Application number	US-202218145541-A
Country	US
Kind code	B2
Filing date	Dec 22, 2022
Priority date	Nov 17, 2021
Publication date	Sep 16, 2025
Grant date	Sep 16, 2025

Abstract

An electrolyte for a secondary battery includes a solvent, a lithium salt, and a film-forming additive. A content of the film-forming additive is 0.1%-10% by mass of a total mass of the electrolyte, and the content of the film-forming additive satisfies:
0.1 * 10 - 2 ≤ A * B M * ( C + N ) ≤ 3 * 10 - 2 .
A is a mass percentage of the film-forming additive in the total mass of the electrolyte. B is an electrolyte retention coefficient of the secondary battery, in g/Ah. M is a mass of a positive electrode active material required per unit capacity of the secondary battery, in g/Ah. N is a mass percentage of nickel in the positive electrode active material contained in the secondary battery. and C is a mass percentage of Co in the positive electrode active material contained in the secondary battery.

First claim

The invention claimed is:

1. An electrolyte for a secondary battery, comprising:
a solvent;
a lithium salt; and
a film-forming additive, a content of the film-forming additive being 0.1%-10% by mass of a total mass of the electrolyte, and the content of the film-forming additive satisfying:

0.1
*

10

-
2

≤

A
*
B

M
*

(

C
+
N

)

≤

3
*

10

-
2

wherein:
A is a mass percentage of the film-forming additive in the total mass of the electrolyte;
B is an electrolyte retention coefficient of the secondary battery, in g/Ah;
M is a mass of a positive electrode active material required per unit capacity of the secondary battery, in g/Ah;
N is a mass percentage of nickel in the positive electrode active material contained in the secondary battery; and
C is a mass percentage of Co in the positive electrode active material contained in the secondary battery.

2. The electrolyte of claim 1 , wherein the content of the film-forming additive satisfies:

0.4

*

10

-
2

≤

A
*
B

M
*

(

C
+
N

)

≤

2
.
1

*
1
⁢

0

-
2

.

3. The electrolyte of claim 1 , wherein the film-forming additive comprises at least one of a difluorophosphate compound, a cyclic carbonate compound, a fluorinated cyclic carbonate compound, a cyclic sulfate compound, or a sulfonate compound.

4. The electrolyte of claim 3 , wherein the film-forming additive comprises the difluorophosphate compound, and the difluorophosphate compound has following structure:

wherein R1 is a hydrogen atom, an oxygen atom, a carbon atom, a nitrogen atom, a sulfur atom, a phosphorus atom, a fluorine atom, an alkyl group, a phenyl group, an alkoxy group, a phenoxy group, a fluorine-containing alkyl group, a fluorine-containing phenyl group, a fluorine-containing alkoxy group, or a fluorine-containing phenoxy group.

5. The electrolyte of claim 4 , wherein:
R1 is the alkyl group, and the alkyl group is a C 1 -C 10 alkyl group;
R1 is the alkoxy group, and the alkoxy group is a C 1 -C 10 alkoxy group;
R1 is the fluorine-containing alkyl group, and the fluorine-containing alkyl group is a C 1 -C 10 fluorine-containing alkyl group; or
R1 is the fluorine-containing alkoxy group, and the fluorine-containing alkoxy group is a C 1 -C 10 fluorine-containing alkoxy group.

6. The electrolyte of claim 3 , wherein the film-forming additive comprises the difluorophosphate compound, and the difluorophosphate compound comprises at least one of butyl difluorophosphate or phenyl difluorophosphate.

7. The electrolyte of claim 3 , wherein:
the film-forming additive comprises the cyclic carbonate compound, and the cyclic carbonate compound comprises at least one of vinylene carbonate or vinyl ethylene carbonate;
the film-forming additive comprises the fluorinated cyclic carbonate compound, and the fluorinated cyclic carbonate compound comprises at least one of fluoroethylene carbonate, 4,4-difluoroethylene carbonate, or 4,5-difluoroethylene carbonate;
the film-forming additive comprises the sulfate compound, and the sulfate compound comprises at least one of 1,3,2-dioxathiolane-2,2-dioxide or 4,4-bis(1,3,2-dioxathiolane)-2,2,2,2-tetraoxide; or
the film-forming additive comprises the sulfonate compound, and the sulfonate compound comprises at least one of 1,3-propane sultone, propylene sultone, butene sultone, or vinyl methanedisulfonate.

8. The electrolyte of claim 1 , wherein the content of the film-forming additive is 0.5%-3% by mass of the total mass of the electrolyte.

9. The electrolyte of claim 1 , wherein the electrolyte retention coefficient of the secondary battery is 2 g/Ah to 4 g/Ah.

10. The electrolyte of claim 1 , wherein the mass of the positive electrode active material required per unit capacity of the secondary battery is in a range of 4 g/Ah to 10 g/Ah.

11. The electrolyte of claim 1 , wherein the lithium salt comprises at least one of LiN(SO 2 F) 2 (LiFSI), LiPF 6 , LiBF 4 , LiN(CF 3 SO 2 ) 2 (LiTFSI), LiClO 4 , LiAsF 6 , LiB(C 2 O 4 ) 2 (LiBOB), LiBF 2 C 2 O 4 (LiDFOB), or lithium difluorobis(oxalato)phosphate (LiDFOP).

12. The electrolyte of claim 1 , wherein the solvent comprises at least one of ethylene carbonate, propylene carbonate, fluoroethylene carbonate, dimethyl carbonate, diethyl carbonate, methyl propyl carbonate, ethyl methyl carbonate, ethyl acetate, methyl acetate, ethyl propionate, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran, or 1,3-dioxolane.

13. A method for evaluating a relationship between a content of a film-forming additive in an electrolyte of a secondary battery and a content of nickel and cobalt in a positive electrode active material, the method comprising causing the content of the film-forming additive, the content of the nickel, and the content of the cobalt to satisfy:

0.1

*
1
⁢

0

-
2

≤

A
*
B

M
*

(

C
+
N

Assignees

• Contemporary Amperex Technology Hong Kong Ltd

Inventors

• Guo Jie
• Han Changlong
• Jiang Bin
• Wu Zeli

Classifications

• H01M10/0569 Primary

  characterised by the solvents · CPC title

• H01M2300/004

  Three solvents · CPC title

• H01M4/131

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M4/364

  as mixtures · CPC title

• H01M2004/028

  Positive electrodes · CPC title