Method and apparatus for preparing dry electrode sheet for secondary battery, dry electrode sheet for secondary battery, electrode for secondary battery and secondary battery

Patent metadata

Field	Value
Publication number	US-12199265-B2
Application number	US-202318321222-A
Country	US
Kind code	B2
Filing date	May 22, 2023
Priority date	May 23, 2022
Publication date	Jan 14, 2025
Grant date	Jan 14, 2025

Abstract

A method of manufacturing a dry electrode sheet for a secondary battery includes providing a dry electrode composition comprising an electrode active material and a binder, a calendering operation of preparing an electrode sheet by passing the dry electrode composition through a calender roll including three or more rolls. The calendering operation includes a first electrode sheet manufacturing operation of manufacturing a first electrode sheet by injecting the dry electrode composition between two adjacent rolls spaced apart from each other by a first interval W1, and an electrode sheet manufacturing operation of manufacturing a dry electrode sheet by inserting the first electrode sheet between two adjacent rolls spaced apart from each other by a second interval W2. The first interval W1 and the second interval W2 have a compression rate of 0.10 or more and 0.65 or less, represented by the equation (1) compression rate=(W1−W2)/W1.

First claim

What is claimed is:

1. A method of manufacturing a dry electrode sheet for a secondary battery, the method comprising:
providing a dry electrode composition comprising an electrode active material and a binder; and
feeding the dry electrode composition directly to a calendering operation
wherein the calendering operation includes:
injecting the dry electrode composition between two adjacent rolls spaced apart from each other by a first interval W1 to provide a first electrode sheet,
inserting the first electrode sheet between two adjacent rolls spaced apart from each other by a second interval W2 to provide the dry electrode sheet, and
wherein the first interval W1 and the second interval W2 have a compression ratio expressed by the following equation (1) of 0.10 or more and 0.27 or less,
Compression Ratio=( W 1− W 2)/ W 1  (equation (1)),

wherein the two adjacent rolls in the injecting step includes a first roll and a second roll, and the two adjacent rolls in the inserting step includes the second roll and a third roll, the dry electrode composition is introduced between the first roll and the second roll to prepare the first electrode sheet, and the first electrode sheet is introduced between the second roll and the third roll to manufacture the dry electrode sheet,
wherein a rotational speed V1 of the first roll, a rotational speed V2 of the second roll, and a rotational speed V3 of the third roll satisfy the following formula (2)
V 1< V 2< V 3  (2),

wherein a rotation speed ratio of the first roll, the second roll and the third roll V1:V2:V3 is 10:11 to 20:12 to 40.

2. The method of claim 1 , wherein the first interval W1 is 100 to 500 μm, and the second interval W2 is 60 to 450 μm.

3. The method of claim 1 , wherein the two adjacent rolls in the injecting step includes the first roll and the second roll, and the two adjacent rolls in the inserting step includes the third roll and a fourth roll,
the dry electrode composition is introduced between the first roll and the second roll to prepare the first electrode sheet, and
the first electrode sheet is introduced between the third roll and the fourth roll to manufacture the dry electrode sheet.

4. The method of claim 3 , wherein the rotational speed V1 of the first roll, the rotational speed V2 of the second roll, the rotational speed V3 of the third roll, and a rotational speed V4 of the fourth roll satisfy the relationship of the following formula (3),
V 1< V 2< V 3< V 4  (3).

5. The method of claim 1 , wherein the injecting and inserting steps occurs at 40° C. to 200° C.

6. The method of claim 1 , wherein the binder is a fiberizable binder.

7. The method of claim 1 , wherein the binder is at least one selected from the group consisting of polytetrafluoroethylene, polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride, cellulose derivative and propionate.

8. The method of claim 1 , further comprising kneading the dry electrode composition.

9. The method of claim 1 , wherein the dry electrode sheet has a tensile strength of 0.50 N/mm2 or more.

10. A method of manufacturing a dry electrode sheet for a secondary battery, the method comprising:
providing a dry electrode composition comprising an electrode active material and a binder; and
feeding the dry electrode composition directly to a calendering operation wherein the calendering operation includes:
injecting the dry electrode composition between two adjacent rolls spaced apart from each other by a first interval W1 to provide a first electrode sheet,
inserting the first electrode sheet between two adjacent rolls spaced apart from each other by a second interval W2 to provide the dry electrode sheet, and
wherein the first interval W1 and the second interval W2 have a compression ratio expressed by the following equation (1) of 0.10 or more and 0.27 or less,
Compression Ratio=( W 1− W 2)/ W 1  (equation (1)),

wherein the two adjacent rolls in the injecting step includes a first roll and a second roll, and the two adjacent rolls in the inserting step includes the second roll, a third roll and a fourth roll, the dry electrode composition is introduced between the first roll and the second roll to prepare the first electrode sheet, and the first electrode sheet is introduced between the third roll and the fourth roll to manufacture the dry electrode sheet,
wherein a rotational speed V1 of the first roll, a rotational speed V2 of the second roll, a rotational speed V3 of the third roll, and a rotational speed V4 of the fourth roll satisfy the following relationship,
V 1> V 2≤ V 3> V 4  (4)

where in formula (4), V1<V4
wherein a rotation speed ratio V1:V2:V3:V4 of the first roll, the second roll, the third roll, and the fourth roll is 10:11 to 20:11 to 20:12 to 40.

Assignees

• Sk On Co Ltd

Inventors

• Kim Jae Youn
• Kang Yong Hee
• Kim Young Jun
• Lee Dong Hoon

Classifications

• H01M10/0404

  Machines for assembling batteries · CPC title

• H01M4/623

  fluorinated polymers · CPC title

• H01M4/38

  of elements or alloys · CPC title

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• B30B11/221

  extrusion dies · CPC title