Secondary battery separator comprising organic/inorganic composite porous layer, and manufacturing method therefor

Patent metadata

Field	Value
Publication number	US-2017331094-A1
Application number	US-201515520281-A
Country	US
Kind code	A1
Filing date	Oct 26, 2015
Priority date	Oct 24, 2014
Publication date	Nov 16, 2017
Grant date	—

Abstract

The present invention relates to a secondary battery separator, and a manufacturing method therefor. The secondary battery separator according to the present invention comprises an organic/inorganic composite porous layer for improving thermal resistance and physical strength, and since the organic/inorganic composite porous layer uses polymer particles as a binder, the secondary battery separator, compared with a separator using a solvent-type binder resin using organic solvents, exhibits excellent permeability.

First claim

What is claimed is:

1 . A porous separator for a secondary battery, comprising:
a polymer porous substrate having pores; and an organic/inorganic composite porous layer formed on at least one surface of the polymer porous substrate, wherein the organic/inorganic composite porous layer includes inorganic particles, binder polymer particles, and an adsorbent polymer binder, and the inorganic particles are coated with the adsorbent polymer binder on at least a portion of surface.

2 . The porous separator for a secondary battery according to claim 1 , wherein a maximum radius of gyration of the adsorbent polymer binder is 1/100 or more and ¼ or less of a median diameter (D50) of the inorganic particles.

3 . The porous separator for a secondary battery according to claim 2 , wherein the maximum radius of gyration of the adsorbent polymer binder is 50 nm or less.

4 . The porous separator for a secondary battery according to claim 1 , wherein the organic/inorganic composite porous layer is a packed structure of the inorganic particles and the binder polymer particles, and is a porous structure having pores formed by interstitial volume between the packed inorganic particles and/or binder polymer particles.

5 . The porous separator for a secondary battery according to claim 1 , wherein an average particle size of the inorganic particles and the binder polymer particles is larger than a median diameter of the pores of the porous substrate.

6 . The porous separator for a secondary battery according to claim 1 , wherein an average particle size of the inorganic particles and the binder polymer particles is a minimum of 20 nm.

7 . The porous separator for a secondary battery according to claim 1 , wherein the binder polymer particles are formed by emulsion polymerization.

8 . The porous separator for a secondary battery according to claim 1 , wherein the inorganic particles are not oxidized and/or reduced within an operating voltage range of the secondary battery.

9 . The porous separator for a secondary battery according to claim 5 , wherein the inorganic particles are inorganic particles having an ability to transport lithium ions and/or high dielectric constant inorganic particles having a dielectric constant of 5 or higher.

10 . A secondary battery comprising a negative electrode, a positive electrode, a separator interposed between the negative electrode and the positive electrode, and an electrolyte solution,
wherein the separator comprises: a polymer porous substrate having pores; and an organic/inorganic composite porous layer formed on at least one surface of the polymer porous substrate, wherein the organic/inorganic composite porous layer includes inorganic particles and binder polymer particles, and the inorganic particles are coated with an adsorbent polymer binder on at least a portion of surface.

11 . The secondary battery according to claim 10 , wherein a maximum radius of gyration of the adsorbent polymer binder is 1/100 or more and ¼ or less of a median diameter (D50) of the inorganic particles.

12 . The secondary battery according to claim 11 , wherein the maximum radius of gyration of the adsorbent polymer binder is 50 nm or less.

13 . The secondary battery according to claim 10 , wherein the organic/inorganic composite porous layer is a packed structure of the inorganic particles and the binder polymer particles are, and is a porous structure having pores formed by interstitial volume between the packed inorganic particles and/or binder polymer particles.

14 . The secondary battery according to claim 10 , wherein an average particle size of the inorganic particles and the binder polymer particles is larger than a median diameter of the pores of the porous substrate.

15 . A method for manufacturing a porous separator for a secondary battery, comprising:
(S10) preparing a polymer porous substrate having pores; (S20) putting and dissolving an adsorbent polymer binder in a solvent; (S30) adding inorganic particles to the result of (S20) and dispersing the same; (S40) putting binder polymer particles in the result of (S30) to prepare a slurry for forming an organic/inorganic composite porous layer; and (S50) applying the slurry of (S40) to the porous substrate prepared at (S10) and drying, wherein the organic/inorganic composite porous layer formed at (S50) includes inorganic particles and binder polymer particles, and is a packed structure of the inorganic particles and the binder polymer particles and is a porous structure having pores formed by interstitial volume between the packed inorganic particles and/or binder polymer particles.

16 . The method for manufacturing a porous separator for a secondary battery according to claim 15 , wherein an average particle size of the inorganic particles and the binder polymer particles is larger than a median diameter of the pores of the porous substrate.

Assignees

• Lg Chemical Ltd

Inventors

• Lee Joo-Sung
• Kim Ji-Eun
• Yu In-Gyoung
• Jin Sun-Mi
• Han Da-Kyung

Classifications

• C08F10/00

  Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond · CPC title

• H01M10/0525

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

• C08F2/22

  Emulsion polymerisation · CPC title

• H01M50/403

  Manufacturing processes of separators, membranes or diaphragms · CPC title

• H01M50/449 Primary

  having a layered structure · CPC title