Polymer composite membrane, preparation method thereof, and lithium-ion battery including the same

Patent metadata

Field	Value
Publication number	US-11223090-B2
Application number	US-201716328993-A
Country	US
Kind code	B2
Filing date	Aug 14, 2017
Priority date	Aug 29, 2016
Publication date	Jan 11, 2022
Grant date	Jan 11, 2022

Abstract

The disclosure provides a polymer composite membrane, a method for preparing same, and a lithium-ion battery including same. The polymer composite membrane includes a polymer base membrane, where the polymer base membrane includes a first surface and a second surface disposed opposite to each other, and the polymer composite membrane further includes a first ceramic layer, a first heat-resistant fiber layer, and a first bonding layer disposed sequentially from inside out on the first surface of the polymer base membrane, where materials of the first heat-resistant fiber layer contain a first polymeric material and a second polymeric material.

First claim

What is claimed is:

1. A polymer composite membrane, comprising:
a polymer base membrane;
a first ceramic layer;
a first heat-resistant fiber layer; and
a first bonding layer,
wherein:
the polymer base membrane comprises a first surface and a second surface disposed opposite to each other;
the polymer base membrane, the first ceramic layer, the first heat-resistant fiber layer, and the first bonding layer are stacked sequentially;
materials of the first heat-resistant fiber layer are a mixture of a first polymeric material and a second polymeric material;
the first polymeric material is a heat-resistant polymeric material whose melting point is above 180° C.; and
a melting point of the second polymeric material is lower than that of the first polymeric material, and a liquid absorption rate of the second polymeric material in an electrolyte at 25° C. is above 40% and has an error of ±5%;
the first bonding layer contains an acrylate crosslinked polymer, a styrene-acrylate crosslinked copolymer and a vinylidene fluoride-hexafluoropropylene copolymer, or the first bonding layer contains an acrylate crosslinked polymer and a styrene-acrylate crosslinked copolymer, or the first bonding layer contains an acrylate crosslinked polymer and a vinylidene fluoride-hexafluoropropylene copolymer, and the porosity of the first bonding layer is 40% to 65%; and
the glass transition temperature of the acrylate crosslinked polymer is −20° C. to 60° C., the glass transition temperature of the styrene-acrylate crosslinked copolymer is −30° C. to 50° C., and the glass transition temperature of the vinylidene fluoride-hexafluoropropylene copolymer is −65° C. to −40° C.

2. The polymer composite membrane according to claim 1 , wherein a liquid absorption rate of the first polymeric material in an electrolyte at 25° C. is below 5% and has an error of ±5%; and
the glass transition temperature of the first polymeric material is above 100° C.; the melting point of the second polymeric material is 100° C. to 150° C.; and the glass transition temperature of the second polymeric material is below 25° C.

3. The polymer composite membrane according to claim 1 , wherein a weight ratio of the first polymeric material to the second polymeric material in the first heat-resistant fiber layer is (0.5 to 10):1.

4. The polymer composite membrane according to claim 1 , wherein
the first polymeric material is selected from one or more of polyetherimide, poly (ether ether ketone), polyether sulfone, polyamide-imide, polyamide acid, and polyvinylpyrrolidone; and
the second polymeric material is selected from one or more of modified polyvinylidene fluoride, polyacrylate, polyphenyl ethylene, and polyethylene oxide; optionally, the modified polyvinylidene fluoride is polyvinylidene fluoride-hexafluoropropylene; and the polyacrylate is one or more of polymethyl acrylate, polyethylene acrylate, and polymethyl methacrylate.

5. The polymer composite membrane according to claim 4 , wherein the first polymeric material is polyetherimide, and the second polymeric material is polyvinylidene fluoride-hexafluoropropylene; and
the materials of the first heat-resistant fiber layer are a mixture of polyetherimide and polyvinylidene fluoride-hexafluoropropylene.

6. The polymer composite membrane according to claim 1 , wherein the diameter of fiber in the first heat-resistant fiber layer is 100 nm to 2000 nm, and the thickness of the first heat-resistant fiber layer is 0.5 μm to 30 μm; and the first heat-resistant fiber layer has a porosity of 75% to 93% and has a surface density of 0.2 g/m 2 to 15 g/m 2 .

7. The polymer composite membrane according to claim 1 , wherein
the first bonding layer contains the acrylate crosslinked polymer and the styrene-acrylate crosslinked copolymer and does not contain the vinylidene fluoride-hexafluoropropylene copolymer, and a weight ratio of the acrylate crosslinked polymer to the styrene-acrylate crosslinked copolymer is 1:(0.05 to 2); or
the first bonding layer contains the acrylate crosslinked polymer and the vinylidene fluoride-hexafluoropropylene copolymer and does not contain the styrene-acrylate crosslinked copolymer, and a weight ratio of the acrylate crosslinked polymer to the vinylidene fluoride-hexafluoropropylene copolymer is 1:(0.3 to 25); or
the first bonding layer contains the acrylate crosslinked polymer, the styrene-acrylate crosslinked copolymer, and the vinylidene fluoride-hexafluoropropylene copolymer, and a weight ratio between the acrylate crosslinked polymer, the styrene-acrylate crosslinked copolymer and the vinylidene fluoride-hexafluoropropylene copolymer is 1:(0.01 to 2):(0.3 to 5).

8. The polymer composite membrane according to claim 1 , wherein the acrylate crosslinked polymer is a mixture of a first acrylate crosslinked polymer and a second acrylate crosslinked polymer and a third acrylate crosslinked polymer, or the acrylate crosslinked polymer is a mixture of a first acrylate crosslinked polymer and a second acrylate crosslinked polymer, or the acrylate crosslinked polymer is a mixture of a first acrylate crosslinked polymer and a third acrylate crosslinked polymer, or the acrylate crosslinked polymer is a second acrylate crosslinked polymer, or the acrylate crosslinked polymer is a third acrylate crosslinked polymer, wherein
the first acrylate crosslinked polymer contains a polymethyl methacrylate chain segment of 70 to 80 wt %, a polyethylene acrylate chain segment of 2 to 10 wt %, a polybutyl acrylate chain segment of 10 to 20 wt %, and a polyacrylic acid chain segment of 2 to 10 wt %, the second acrylate crosslinked polymer contains a polymethyl methacrylate chain segment of 30 to 40 wt %, a polyethylene acrylate chain segment of 2 to 10 wt %, a polybutyl acrylate chain segment of 50 to 60 wt %, and a polyacrylic acid chain segment of 2 to 10 wt %, and the third acrylate crosslinked polymer contains a polymethyl methacrylate chain segment of 50 to 80 wt %, a polyethylene acrylate chain segment of 2 to 10 wt %, a polybutyl acrylate chain segment of 15 to 40 wt %/o, and a polyacrylic acid chain segment of 2 to 10 wt %; the glass transition temperature of the first acrylate crosslinked polymer is 50° C. to 60° C., the glass transition temperature of the second acrylate crosslinked polymer is −20° C. to −5° C., and the glass transition temperature of the third acrylate crosslinked polymer is 30° C. to 50° C.;
the styrene-acrylate crosslinked copolymer contains a polyphenyl ethylene chain segment of 40 to 50 wt/o, a polymethyl methacrylate chain segment of 5 to 15 wt %, a polyethylene acrylate chain segment of 2 to 10 wt %, a polybutyl acrylate chain segment of 30 to 40 wt %, and a polyacrylic acid chain segment of 2 to 10 wt %; and the glass transition temperature of the styrene-acrylate crosslinked copolymer is 15° C. to 30° C.; and
the vinylidene fluoride-hexafluoropropylene copolymer contains a polyvinylidene fluoride chain segment of 80 to 98 wt % and a polyhexafluoropropylene chain segment of 2 to 20 wt %; and the glass transition temperature of the vinylidene fluoride-hexafluoropropylene copolymer is −60° C. to −40° C.

9. The polymer composite membrane according to claim 1 , wherein
the first bonding layer contains a first acrylate crosslinked polymer, a second acrylate crosslinked polymer, and the styrene-acrylate crosslinked copolymer and does not contain the vinylidene fluoride-hexafluoropropylene copolymer, and a weight ratio between the first acrylate crosslinked polymer, the second acrylate crosslinked polymer and the styrene-acrylate crosslinked copolymer is (5 to 10):1:(10 to 13), or
the first bonding layer contains the first acrylate crosslinked polymer, the second acrylate crosslinked polymer, an

Assignees

• Byd Co Ltd

Inventors

• Hu Jialing
• Shan Jun
• Hu Gang
• He Long

Classifications

• H01M10/052 Primary

  Li-accumulators · CPC title

• H01M50/457 Primary

  comprising three or more layers · CPC title

• H01M50/417

  Polyolefins · CPC title

• H01M50/434

  Ceramics · CPC title

• H01M50/489

  Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties · CPC title