Separator and lithium-ion secondary battery

Patent metadata

Field	Value
Publication number	US-9711773-B2
Application number	US-201414584730-A
Country	US
Kind code	B2
Filing date	Dec 29, 2014
Priority date	May 14, 2014
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

The present disclosure provides a separator and a lithium-ion secondary battery. The separator comprises: a microporous membrane having micropores; and a coating provided on a surface of the microporous membrane. The coating comprises polymer particles and binder particles. The polymer particle is a hollow shell structure which comprises a shell and a cavity positioned in the shell, an outer surface of the shell is distributed with nanopores which are communicated with the cavity, a particle diameter of the polymer particle is larger than a pore size of the micropore of the microporous membrane; a particle diameter of the binder particle is larger than the pore size of the micropore of the microporous membrane. The lithium-ion secondary battery comprises: a positive electrode plate; a negative electrode plate; the aforementioned separator interposed between the positive electrode plate and the negative electrode plate; and an electrolyte.

First claim

What is claimed is:

1. A separator, comprising:
a microporous membrane having micropores; and
a coating provided on a surface of the microporous membrane and comprising:
polymer particles, each polymer particle having a hollow shell structure and comprising a shell and a cavity positioned in the shell, an outer surface of the shell being distributed with nanopores which are communicated with the cavity, a particle diameter of the polymer particle being larger than a pore size of the micropore of the microporous membrane; and
binder particles, a particle diameter of each binder particle being larger than the pore size of the micropore of the microporous membrane.

2. The separator according to claim 1 , wherein a thickness of the microporous membrane is 3 μm˜35 μm; a thickness of the coating is 0.5 μm˜6 μm.

3. The separator according to claim 1 , wherein the polymer particle is formed by copolymerizing at least two monomers selected from styrene, acrylic acid, methacrylic acid, methyl styrene, vinyl toluene, methyl acrylate, isobutyl acrylate, n-octyl acrylate, vinyl acrylate, cyclohexyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, n-butyl methacrylate, ethyl methacrylate, and methyl methacrylate.

4. The separator according to claim 1 , wherein a glass transition temperature of the polymer particle is 95° C.˜125° C.

5. The separator according to claim 1 , wherein the pore size of the micropore of the microporous membrane is 35 nm˜800 nm; the particle diameter of the polymer particle is 50 nm˜900 nm; the particle diameter of the binder particle is 60 nm˜1000 nm.

6. The separator according to claim 1 , wherein the particle diameter of the polymer particle allows at least 5% and less than 50% of a volume of the polymer particle to be embedded into the micropore of the microporous membrane.

7. The separator according to claim 1 , wherein an area of the nanopores distributed on the outer surface of the shell of the polymer particle is 10%˜50% of the outer surface area of the shell.

8. The separator according to claim 1 , wherein taking a thickness of the shell of the polymer particle as a length of a channel of the nanopore, the pore size of the nanopore is 20%˜50% of the thickness of the shell of the polymer particle.

9. The separator according to claim 1 , wherein the pore size of the nanopore is 10 nm˜30 nm.

10. A lithium-ion secondary battery, comprising:
a positive electrode plate;
a negative electrode plate;
a separator interposed between the positive electrode plate and the negative electrode plate; and
an electrolyte;
the separator comprising:
a microporous membrane having micropores; and
a coating provided on a surface of the microporous membrane and comprising:
polymer particles, each polymer particle having a hollow shell structure and comprising a shell and a cavity positioned in the shell, an outer surface of the shell being distributed with nanopores which are communicated with the cavity, a particle diameter of the polymer particle being larger than a pore size of the micropore of the microporous membrane; and
binder particles, a particle diameter of each binder particle being larger than the pore size of the micropore of the microporous membrane.

11. The lithium-ion secondary battery according to claim 10 , wherein a thickness of the microporous membrane is 3 μm˜35 μm; a thickness of the coating is 0.5 μm˜6 μm.

12. The lithium-ion secondary battery according to claim 10 , wherein the polymer particle is formed by copolymerizing at least two monomers selected from styrene, acrylic acid, methacrylic acid, methyl styrene, vinyl toluene, methyl acrylate, isobutyl acrylate, n-octyl acrylate, vinyl acrylate, cyclohexyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, n-butyl methacrylate, ethyl methacrylate, and methyl methacrylate.

13. The lithium-ion secondary battery according to claim 10 , wherein a glass transition temperature of the polymer particle is 95° C.˜125° C.

14. The lithium-ion secondary battery according to claim 10 , wherein the pore size of the micropore of the microporous membrane is 35 nm˜800 nm; the particle diameter of the polymer particle is 50 nm˜900 nm; the particle diameter of the binder particle is 60 nm˜1000 nm.

15. The lithium-ion secondary battery according to claim 10 , wherein the particle diameter of the polymer particle allows at least 5% and less than 50% of a volume of the polymer particle to be embedded into the micropore of the microporous membrane.

16. The lithium-ion secondary battery according to claim 10 , wherein an area of the nanopores distributed on the outer surface of the shell of the polymer particle is 10%˜50% of the outer surface area of the shell.

17. The lithium-ion secondary battery according to claim 10 , wherein taking a thickness of the shell of the polymer particle as a length of a channel of the nanopore, the pore size of the nanopore is 20%˜50% of the thickness of the shell of the polymer particle.

18. The lithium-ion secondary battery according to claim 10 , wherein the pore size of the nanopore is 10 nm˜30 nm.

Assignees

• Dongguan Amperex Tech Ltd

Inventors

• Lai Xulun
• Jiang Hui
• Yang Jianrui
• Zhan Kejun
• Niu Lei

Classifications

• H01M10/0525 Primary

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

• H01M50/497

  Ionic conductivity · CPC title

• H01M50/469

  tubular or cylindrical · CPC title

• H01M50/451

  comprising layers of only organic material and layers containing inorganic material · CPC title

• H01M50/491

  Porosity · CPC title