Separation membrane comprising coating layer, method of preparing same, and battery using same

Patent metadata

Field	Value
Publication number	US-2021036294-A1
Application number	US-202017073664-A
Country	US
Kind code	A1
Filing date	Oct 19, 2020
Priority date	Aug 1, 2012
Publication date	Feb 4, 2021
Grant date	—

Abstract

Also, disclosed herein is an electrochemical battery having improved thermal stability by using the separator including a coating layer containing polyamic acid.

First claim

1 - 14 . (canceled)

15 . A separator, comprising:
a polyolefin-based substrate film, and a coating layer positioned at least one of surface of the polyolefin-based substrate film, wherein the coating layer is formed from a composition comprising an organic binder including a polyamic acid represented by the following Chemical Formula 1 or Chemical Formula 2, a low boiling point solvent having a boiling point less than 150° C., and a high boiling point solvent having a boiling point of 150° C. or more:

wherein:
R 1 , R 5 , and R 7 include, independently of one another, an unsubstituted or substituted aromatic hydrocarbon having 6 to 30 carbon atoms; an unsubstituted or substituted aliphatic hydrocarbon having 2 to 20 carbon atoms; or an unsubstituted or substituted alicyclic hydrocarbon having 3 to 24 carbon atoms;
R 2 , R 6 , and R 8 include, independently of one another, an unsubstituted or substituted aromatic hydrocarbon having 6 to 30 carbon atoms; an unsubstituted or substituted aliphatic hydrocarbon having 2 to 20 carbon atoms; an unsubstituted or substituted alicyclic hydrocarbon having 3 to 24 carbon atoms; or —R 3 —Ar 5 —R 4 —, wherein R 3 and R 4 include, independently of each other, an alkylene having 1 to 5 carbon atoms; and Ar 5 includes an arylene having 6 to 15 carbon atoms that is unsubstituted or mono- to tri-substituted by CH 3 , OH, SH, or NH 2 ;
n is an integer of 30 to 10000; and
x is an integer of 15 to 5000, and y is an integer of 15 to 5000.

16 . The separator as claimed in claim 15 , wherein the polyamic acid is contained in 1 to 30% by weight, based on a total weight of the composition.

17 . The separator as claimed in claim 15 , wherein the low boiling point solvent is selected from acetone, tetrahydrofuran (THF), or combination thereof.

18 . The separator as claimed in claim 15 , wherein the high boiling point solvent is selected from dimethylformamide (DMF), dimethylsulfoxide (DMSO), N,N-dimethylacetamide (DMAc), dimethylcarbonate (DMC), N-methylpyrrolidone (NMP), or combination thereof.

19 . The separator as claimed in claim 15 , wherein the low boiling point solvent and the high boiling point solvent are included in a weight ratio of 9.5:0.5 to 5:5.

20 . The separator as claimed in claim 15 , wherein the low boiling point solvent is acetone and the high boiling point solvent is N,N-dimethylacetamide.

21 . The separator as claimed in claim 15 , wherein a residual amount of the low boiling point solvent and the high boiling point solvent in the separator after drying is 500 ppm or less.

22 . The separator as claimed in claim 15 , wherein R 1 , R 5 , and R 7 include, independently of one another, an aromatic hydrocarbon represented by the following Chemical Formula 3, and R 2 , R 6 , and R 8 include, independently of one another, an aromatic hydrocarbon represented by the following Chemical Formula 4:

wherein, in Chemical Formula 3:
Ar 1 to Ar 4 include, independently of one another, an unsubstituted or substituted arylene having 6 to 15 carbon atoms;
X 1 to X 3 include, independently of one another, a single bond, O, S, C(═O), S(═O) 2 , C(═O)NH, an unsubstituted or substituted alkylene having 1 to 10 carbon atoms, or an unsubstituted or substituted silylene; and
m, l, and o are, independently of one another, 0 or 1; with the provisos that:
if m is 1, and l and o are 0, X 2 and X 3 are a single bond, and Ar 2 is an unsubstituted or substituted trivalent arylene having 6 to 15 carbon atoms;
if m and l are 1, and o is 0, X 3 is a single bond, and Ar is an unsubstituted or substituted trivalent arylene having 6 to 15 carbon atoms; and
if m, l, and o are all 0, X 1 to X 3 are a single bond, and Ar 1 is an unsubstituted or substituted tetravalent arylene having 6 to 15 carbon atoms;
—(Ar 6 )—X 4 —(Ar 7 ) p —X 5 —(Ar 8 ) q —X 6 —(Ar 9 ) r —  [Chemical Formula 4]

wherein, in Chemical Formula 4:
Ar 6 to Ar 9 include, independently of one another, an unsubstituted or substituted arylene having 6 to 15 carbon atoms;
X 4 to X 6 include, independently of one another, a single bond, O, S, C(═O), S(═O) 2 , C(═O)NH, an unsubstituted or substituted alkylene having 1 to 10 carbon atoms, or an unsubstituted or substituted silylene; and
p, q, and r are, independently of one another, 0 or 1; with the provisos that:
if p is 1, and q and r are 0, X 5 and X 6 are a single bond;
if p and q are 1, and r is 0, X 6 is a single bond; and
if p, q, and r are all 0, X 4 to X 6 are a single bond.

23 . The separator as claimed in claim 15 , wherein the polyamic acid has a structure of following Chemical Formula 9:

wherein a ratio of repeating units x to y is 9:1 to 7:3.

24 . The separator as claimed in claim 23 , wherein one or more aryl sulfone groups in the repeating unit x or y of the Chemical Formula 9 are a meta-aryl sulfone group.

25 . The separator as claimed in claim 15 , wherein the separator has a breaking temperature of 180° C. or more under a condition of 0.005 N, and a heating rate of 5° C./min.

26 . The separator as claimed in claim 15 , wherein the composition further contains inorganic particles, and
wherein the inorganic particles are contained in 10 to 70% by weight, based on a total weight of the composition.

27 . The separator as claimed in claim 15 , wherein the composition further contains an additional binder selected from the group of polyvinylidene fluoride (PVdF) homopolymer, polyvinylidene fluoride-hexafluoropropylene copolymer (PVdF-HFP), polymethylmethacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene-co-vinyl acetate, polyethylene oxide, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylpullulan, cyanoethylpolyvinylalcohol, cyanoethylcellulose, cyanoethylsucrose, pullulan, carboxyl methyl cellulose, and acrylonitrilestyrene-butadiene copolymer, alone or in a mixture thereof.

28 . The separator as claimed in claim 15 , wherein the additional binder is selected from polyvinylidene fluoride homopolymer, polyvinylidene fluoride-hexafluoropropylene copolymer, or combination thereof.

29 . A method of preparing a separator comprising a step of applying a composition containing a polyamic acid represented by the following Chemical Formula 1 or Chemical Formula 2, a low boiling point solvent having a boiling point less than 150° C., and a high boiling point solvent having a boiling point of 150° C. or more on at least one of surface of a polyolefin-based substrate film, and a step of drying the applied composition to form a coating layer,

wherein:
R 1 , R 5 , and R 7 include, independently of one another, an unsubstituted or substituted aromatic hydrocarbon having 6 to 30 carbon atoms; an unsubstituted or substituted aliphatic hydrocarbon having 2 to 20 carbon atoms; or an unsubstituted or substituted alicyclic hydrocarbon having 3 to 24 carbon atoms;
R 2 , R 6 , and R 8 include, independently of one another, an unsubstituted or substituted aromatic hydrocarbo

Assignees

• Samsung Sdi Co Ltd

Inventors

• Jeon In Sik
• Park Jin Kyu
• Park Tae Joon
• Chung Jun Ho
• Jin Mok Yun

Classifications

• C08G73/1042 Primary

  Copolyimides derived from at least two different tetracarboxylic compounds or two different diamino compounds · CPC title

• H01M50/443

  Particulate material · CPC title

• H01M50/451

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

• H01M50/414 Primary

  Synthetic resins, e.g. thermoplastics or thermosetting resins · CPC title