# US 12,009,502 B2 · Method of producing negative electrode

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- Number: US 12,009,502 B2
- Document ID: US12009502B2
- Status: Granted
- Kind: B2
- Application number: 17/605,009
- Filed: 2020-05-07
- Published: 2022-07-07
- Granted: 2024-06-11
- Earliest claimed: 2019-05-10
- Assignees: LG Energy Solution, Ltd.
- Applicants: LG Energy Solution, Ltd.
- Inventors: Oh Byong Chae; Ye Ri Kim
- Web page: https://patentgrep.com/patent/US12009502B2

## CPC

- H01M 4/0452: {from solutions}
- H01M 4/139: Processes of manufacture
- H01M 4/0416: {involving impregnation with a solution, dispersion, paste or dry powder (H01M4/0438 takes precedence)}
- H01M 4/043: {involving compressing or compaction}
- H01M 4/0445: {Forming after manufacture of the electrode, e.g. first charge, cycling}
- H01M 4/364: {as mixtures}
- H01M 4/382: {Lithium (H01M4/405 takes precedence)}
- H01M 4/587: for inserting or intercalating light metals
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 4/483: {for non-aqueous cells (H01M4/485 takes precedence)}
- H01M 2004/027: {Negative electrodes}
- Y02E 60/10: Energy storage using batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A method of producing a negative electrode is disclosed which is capable of preventing volume expansion and structural deformation caused by pre-lithiation, maintaining proximity and contact between negative electrode active materials, preventing an increase in resistance of a negative electrode, and realizing an excellent capacity retention rate by performing pre-lithiation while pressurizing a negative electrode at a specific pressure. In addition, the method of producing a negative electrode is capable of improving quality consistency of a product and processability by performing pre-lithiation of a negative electrode in a roll-to-roll manner.

## Claims

### Claim 1

A method of producing a negative electrode, comprising:
providing a negative electrode roll on which a negative electrode structure including a negative electrode current collector and a negative electrode active material layer formed on at least one surface of the negative electrode current collector is wound;
providing a pre-lithiation bath containing a pre-lithiation solution, the pre-lithiation bath being sequentially divided into an impregnation section and a pre-lithiation section;
impregnating the negative electrode structure with the pre-lithiation solution while unwinding the negative electrode structure from the negative electrode roll and moving the negative electrode structure through the impregnation section; and
pre-lithiating the impregnated negative electrode structure by disposing the impregnated negative electrode structure in the pre-lithiation section,
wherein the pre-lithiating the impregnated negative electrode structure includes:
(a) disposing the impregnated negative electrode structure between two pre-lithiation structures, each pre-lithiation structure including a separator layer disposed to face the negative electrode active material layer and a lithium counter electrode layer located on the separator layer;
(b) electrochemical charging the impregnated negative electrode structure while pressurizing the impregnated negative electrode structure at a pressure of 10 kPa to 3,500 kPa with the two pre-lithiation structures to form a pre-lithiated negative electrode structure; and
(c) separating the two pre-lithiation structures from the pre-lithiated negative electrode structure and moving the pre-lithiated negative electrode structure out of the pre-lithiation section.

### Claim 2 (depends on 1)

The method of claim 1, wherein step (b) is performed for 5 minutes to 120 minutes.

### Claim 3 (depends on 1)

The method of claim 1, wherein a time taken for the negative electrode structure to move through the impregnation section is 1 times to 10 times a time taken to perform step (b).

### Claim 4 (depends on 1)

The method of claim 1, wherein the pre-lithiation bath is sequentially divided into the impregnation section, the pre-lithiation section, and an aging section, and
wherein the method further comprises aging the pre-lithiated negative electrode structure having passed through the pre-lithiation section by conveying the pre-lithiated negative electrode structure to the aging section.

### Claim 5 (depends on 4)

The method of claim 4, wherein a time taken for the pre-lithiated negative electrode structure to move through the aging section is 0.5 times to 21 times the time taken to perform step (b).

### Claim 6 (depends on 4)

The method of claim 4, further comprising washing the aged negative electrode structure by taking the aged negative electrode structure out of the pre-lithiation bath, introducing the aged negative electrode structure into a washing bath containing an organic solvent, and moving the aged negative electrode structure through the washing bath to form a washed negative electrode structure.

### Claim 7 (depends on 6)

The method of claim 6, further comprising drying the washed negative electrode structure.

### Claim 8 (depends on 1)

The method of claim 1, further comprising washing the pre-lithiated negative electrode structure by taking the pre-lithiated negative electrode structure out of the pre-lithiation bath, introducing the pre-lithiated negative electrode structure into a washing bath containing an organic solvent, and moving the pre-lithiated negative electrode structure through the washing bath to form a washed negative electrode structure.

### Claim 9 (depends on 8)

The method of claim 8, wherein a time taken for the pre-lithiated negative electrode structure to move through the washing bath is 0.1 times to 5 times a time taken to perform step (b).

### Claim 10 (depends on 8)

The method of claim 8, further comprising drying the washed negative electrode structure.

### Claim 11 (depends on 10)

The method of claim 10, wherein the time taken to dry the washed negative electrode structure is 0.1 times to 5 times the time taken to perform step (b).

### Claim 12 (depends on 1)

The method of claim 1, wherein a temperature of the pre-lithiation bath ranges from 10° C. to 80° C.

### Claim 13 (depends on 1)

The method of claim 1, wherein each of the pre-lithiation structures further includes a supporting plate located on the lithium counter electrode layer and an insulating plate located on the supporting plate.

### Claim 14 (depends on 13)

The method of claim 13, wherein the pre-lithiation structures are connected by a plurality of supports such that the pre-lithiation structures are movable along the plurality of supports.