Composite electrode for a lithium or lithium-ion battery and production method therefor

Patent metadata

Field	Value
Publication number	US-12394777-B2
Application number	US-202017636622-A
Country	US
Kind code	B2
Filing date	Jul 17, 2020
Priority date	Aug 19, 2019
Publication date	Aug 19, 2025
Grant date	Aug 19, 2025

Abstract

A method for producing a composite electrode for a lithium or lithium-ion battery comprises: providing a current collector having a main surface; forming a first electrode layer on the main surface of the current collector, wherein a first adhesion is formed between the current collector and the first electrode layer along the main surface; forming a second electrode layer on the first electrode layer, wherein the first and second electrode layer contact each other along a contact surface opposite the main surface of the current collector, the second electrode layer is adhesively connected to the first electrode layer along the contact surface; and compressing the first and second electrode layer by means of a compression device, wherein, during the compressing, a pressure element of the compression device exerts a pressure on at least one part of the surface of the second electrode layer opposite the contact surface, and a second adhesion can form between the pressure element and the part of the second electrode layer on which the pressure is exerted, wherein the ratio between the first adhesion and the second adhesion resulting from the compression is greater than one.

First claim

What is claimed is:

1. A method for producing a composite electrode for a lithium or lithium-ion battery, comprising:
providing a foil-like or planar current collector having a main face;
forming a first electrode layer on the main face of the current collector, wherein the first electrode layer comprises a first active material and a first binder and forms a first adherence between the current collector and the first electrode layer along the main face;
forming a second electrode layer on the first electrode layer, wherein the first and second electrode layer are mutually touching along a contact face which lies opposite the main face of the current collector, and the second electrode layer comprises a second active material and a second binder and has an adherent connection to the first electrode layer along the contact face; and
compressing the first and second electrode layer using a compression device, wherein, during the compression, a pressure element of the compression device exerts a pressure on at least a portion of the face of the second electrode layer that lies opposite the contact face, a face of the pressure element having a roughness comprising a mean roughness depth, Rz, of less than 2 μm, and a second adherence forms between the pressure element and the portion of the face of the second electrode layer on which the pressure is exerted, and
wherein a ratio between the first adherence and the second adherence which arises as a result of the compression is greater than one.

2. The method according to claim 1 , wherein the ratio between the first adherence and the second adherence which arises as a result of the compression is greater than two.

3. The method according to claim 2 , wherein the ratio between the first adherence and the second adherence which arises as a result of the compression is greater than five.

4. The method according to claim 1 , wherein the first electrode layer further comprises a first conductive additive, wherein the first binder, firstly, binds the first active material and the first conductive additive and, secondly, forms the first adherence between the first electrode layer and the current collector, and/or
wherein the second electrode layer further comprises a second conductive additive, wherein the second binder binds the second active material and the second conductive additive,
wherein the adherent connection between the first electrode layer and the second electrode layer is formed along the contact face thereof by the first binder and/or the second binder.

5. The method according to claim 4 , wherein the first electrode layer contains the first active material and the first conductive additive in the form of particles, and a third adherence develops between the particles and the first binder,
wherein the second electrode layer contains the second active material and the second conductive additive in the form of particles, and a fourth adherence develops between the particles and the second binder, and
wherein the second adherence arising as a result of the compression is lower than the third adherence, lower than the fourth adherence and lower than the adherent connection between the first and second electrode layer.

6. The method according to claim 5 , wherein the first binder and the second binder comprise different substances.

7. The method according to claim 5 , wherein the first binder and the second binder comprise identical substances, but the concentration of the first binder in the first electrode layer is higher than the concentration of the second binder in the second electrode layer.

8. The method according to claim 4 , wherein forming the first electrode layer comprises:
mixing the first active material, the first conductive additive and the first binder to form a first substance mixture, and
applying the first substance mixture to the main face of the current collector; and
wherein forming the second electrode layer comprises:
mixing the second active material, the second conductive additive and the second binder to form a second substance mixture, and
applying the second substance mixture to the first electrode layer,
wherein, upon or after the application of the second substance mixture, the first binder and the second binder flow into one another at the contact face between the first and second electrode layer.

9. The method according to claim 1 , wherein the first active material and the second active material are identical.

10. The method according to claim 1 , wherein the first active material and the second active material are different.

11. The method according to claim 1 , wherein the roughness comprises an average roughness, Ra, of less than 1 μm.

12. The method according to claim 1 , wherein the compression device includes calender rollers, and wherein the pressure element is the calender roller which comes into contact with the portion of the face of the second electrode layer during the compression.

13. A composite electrode for a lithium or lithium-ion battery made by the method according to claim 1 .

Assignees

• Bayerische Motoren Werke Ag

Inventors

• Kim Sung-Jin
• Ogihara Hideki
• Tsiouvaras Nikolaos
• Woehrle Thomas

Classifications

• H01M2004/027

  Negative electrodes · CPC title

• H01M2004/021

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

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M4/661

  Metal or alloys, e.g. alloy coatings (H01M4/669 take precedence) · CPC title

• H01M4/625

  Carbon or graphite · CPC title