Electrode having bilayer structure and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-10797305-B2
Application number	US-201715775273-A
Country	US
Kind code	B2
Filing date	Mar 15, 2017
Priority date	Mar 16, 2016
Publication date	Oct 6, 2020
Grant date	Oct 6, 2020

Abstract

Provided is an electrode for a secondary battery having an electrode current collector either surface or both surfaces of which are coated with two active material layers, the electrode including: an electrode current collector; a first layer of active material coated on the current collector; and a second layer of active material coated on the first layer of active material, wherein a plurality of craters are formed in the first layer of active material and the craters are filled with active material of the second layer. A method for manufacturing the electrode for a secondary battery is also provided, and the method includes carrying out laser ablation on the first layer of active material. According to the present disclosure, it is possible to solve the problem of detachment of the active material layers, particularly the second layer of active material, during the process for manufacturing the electrode.

First claim

What is claimed is:

1. An electrode for a secondary battery having an electrode current collector either surface or both surfaces of which are coated with two active material layers, the electrode comprising:
an electrode current collector; a first layer of active material coated on the current collector; and a second layer of active material coated on the first layer of active material, wherein a second average particle diameter of the active material forming the second layer of active material is larger than a first average particle diameter of the active material forming the first layer of active material, with a ratio of the first average particle diameter to the second average particle diameter being from 1:9 to 5:5.1, and
wherein a plurality of craters are formed in the first layer of active material by laser ablation and the craters are filled with active material of the second layer.

2. The electrode for a secondary battery according to claim 1 , wherein the craters have a diameter of 2-60 μm.

3. The electrode for a secondary battery according to claim 1 , wherein the craters have a depth of 2-60 μm.

4. The electrode for a secondary battery according to claim 1 , wherein the craters have a semi-spherical shape or a flower-like shape having a plurality of petals.

5. The electrode for a secondary battery according to claim 1 , wherein the craters occupy 1-50% of the surface area of the first layer of active material.

6. A method for manufacturing an electrode for a secondary battery having an electrode current collector either surface or both surfaces of which are coated with two active material layers, the method comprising the steps of:
(i) preparing a first electrode mixture slurry for forming a first layer of active material and coating the first electrode mixture slurry onto the electrode current collector, followed by drying;
(ii) carrying out pressing to form the first layer of active material;
(iii) forming craters in a surface of the first layer of active material by melting or evaporating the active material at discrete locations on the surface of the first layer via laser ablation;
(iv) preparing second electrode mixture slurry for forming a second layer of active material and coating the second electrode mixture slurry onto the first layer of active material, followed by drying; and
(v) carrying out pressing to form the second layer of active material, wherein at least a portion of the second layer of active material is received within some of the craters in the first layer of active material[H] wherein a second average particle diameter of the active material forming the second layer of active material is larger than a first average particle diameter of the active material forming the first layer of active diameter being from 1;9 to 5;5.1.

7. The method for manufacturing an electrode for a secondary battery according to claim 6 , wherein the laser is IR laser, eximer laser, YAG laser or CO 2 laser.

8. The method for manufacturing an electrode for a secondary battery according to claim 6 , wherein the laser has an output of 0.1-20 W.

9. The method for manufacturing an electrode for a secondary battery according to claim 6 , wherein the laser ablation is carried out at a speed of 2,500 mm/s or less.

10. The method for manufacturing an electrode for a secondary battery according to claim 6 , wherein the steps are performed along a processing line in which the electrode current collector is conveyed between sequential locations along the processing line where the respective steps are performed.

11. The method for manufacturing an electrode for a secondary battery according to claim 10 , wherein the step of forming craters via laser ablation is performed at a first one of the sequential locations while the electrode current collector with the first layer of active material thereon is conveyed towards a second one of the sequential locations where the coating of the second electrode mixture slurry onto the first layer of active material is performed, the coating of the second electrode mixture slurry onto the first layer of active material being performed at the second location while the electrode current collector with the first layer of active material thereon is being conveyed.

12. The method for manufacturing an electrode for a secondary battery according to claim 6 , wherein the ratio of the first average particle diameter to the second average particle diameter is from 1:1.625 to 1:4.

13. The method for manufacturing an electrode for a secondary battery according to claim 6 , wherein a press density ratio of the first layer of active material to the second layer of active material is from 1.1:1 to 3:1 under a pressure of 12-16 Mpa.

14. The method for manufacturing an electrode for a secondary battery according to claim 6 , wherein the craters are formed to define a shape having a central region with a plurality of lobes extending radially outwardly therefrom.

15. The electrode for a secondary battery according to claim 1 , wherein the ratio of the first average particle diameter to the second average particle diameter is from 1:1.625 to 1:4.

16. The electrode for a secondary battery according to claim 1 , wherein a press density ratio of the first layer of active material to the second layer of active material is from 1.1:1 to 3:1 under a pressure of 12-16 Mpa.

Assignees

• Lg Chemical Ltd

Inventors

• Kim Hyuk-Su

Classifications

• H01M4/133

  Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title

• H01M4/131

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

• H01M2004/021

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

• H01M4/13 Primary

  Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof · CPC title

• H01M4/0404

  by coating on electrode collectors · CPC title