Electrode assembly having improved flexural rigidity, method for preparing same, and electrochemical battery comprising same

Patent metadata

Field	Value
Publication number	US-2016293999-A1
Application number	US-201415038352-A
Country	US
Kind code	A1
Filing date	Nov 21, 2014
Priority date	Nov 21, 2013
Publication date	Oct 6, 2016
Grant date	—

Abstract

The present invention relates to an electrode assembly, a method for preparing the same, and an electrochemical battery including the same, wherein the electrode assembly comprises: a cathode including a cathode active material and a cathode current collector; an anode including an anode active material and an anode current collector; and a separator interposed between the cathode and the anode. The electrode assembly has a flexural rigidity of 15 kgf/cm 2 or more when pressed using a pressure of 1 kgf/cm 2 to 30 kgf/cm 2 for 1 second to 15 seconds at 20 ° C. to 110 ° C.

First claim

What is claimed is:

1 . An electrode assembly comprising a cathode including a positive active material and a cathode current collector, an anode including an anode active material and a anode current collector, and a separator disposed between the cathode and the anode, wherein the electrode assembly has a flexural rigidity of greater than or equal to 15 kgf/cm 2 when being compressed at 20° C. to 110° C. for 1 second to 15 seconds, with a pressure of 1 kgf/cm 2 to 30 kgf/cm 2 .

2 . The electrode assembly of claim 1 , wherein the separator comprises a porous substrate and a porous adhesive layer disposed on one surface or both surfaces of the porous substrate and including an acryl-based copolymer including a(meth)acrylate-based monomer-derived repeating unit.

3 . The electrode assembly of claim 2 , wherein the acryl-based copolymer further comprises an acetate group-containing monomer-derived repeating unit.

4 . The electrode assembly of claim 2 , wherein the (meth)acrylate-based monomer-derived repeating unit is a repeating unit derived from at least one monomer selected from the group consisting of methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, and butyl(meth)acrylate.

5 . The electrode assembly of claim 3 , wherein the acetate group-containing monomer-derived repeating unit is a repeating unit derived from allyl acetate or vinyl acetate.

6 . The electrode assembly of claim 2 , wherein the porous adhesive layer further comprises an inorganic particle, and the inorganic particle is included in an amount of 70 wt % to 95 wt % based on the total weight of the porous adhesive layer.

7 . The electrode assembly of claim 2 , wherein the porous adhesive layer further comprises a polyvinylidene fluoride-based binder.

8 . The electrode assembly of claim 7 , wherein the polyvinylidene fluoride-based binder is at least one selected from a polyvinylidene fluoride (PVDF) homopolymer, polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), polyvinylidene fluoride-trichloroethylene (PVDF-TCE), and polyvinylidene fluoride-chlorotrifluoroethylene (PVDF-CTFE).

9 . The electrode assembly of claim 7 , wherein a weight ratio of the acryl-based copolymer and the polyvinylidene fluoride-based binder is 9.9:0.1 to 2.5:7.5.

10 . The electrode assembly of claim 1 , wherein the electrode assembly has a compression thickness variation ratio of greater than or equal to 10% according to Equation 1:
Compression thickness variation ratio (%)=[(Thickness of an electrode assembly compressed at 20° C.−Thickness of an electrode assembly compressed at 100° C.)/Thickness of an electrode assembly compressed at 20° C]×100   [Equation 1]
wherein, in Equation 1, the thickness of an electrode assembly compressed at 20° C. is a thickness of a central portion of an electrode assembly including a stacked cathode/separator/anode after compressing it at 20° C. for 1 second to 10 seconds, with a pressure of 1 kgf/cm 2 to 30 kgf/cm 2 and measuring the thickness in one 1 hour, and the thickness of an electrode assembly compressed at 100° C. is a thickness of a central portion of the electrode assembly for 1 second to 10 seconds, with a pressure of 1 kgf/cm 2 to 30 kgf/cm 2 and measuring the thickness in one 1 hour.

11 . An electrochemical battery comprising the electrode assembly of claim 1 .

12 . The electrochemical battery of claim 11 , wherein the electrochemical battery is a lithium polymer secondary battery or a lithium ion polymer secondary battery.

13 . A method of preparing an electrode assembly, comprising forming a positive active material layer on a cathode current collector to prepare a cathode, forming an anode active material layer on a anode current collector to prepare an anode, disposing a separator between the cathode and the anode, and compressing the cathode/separator/anode structure at 20° C. to 110° C. for 1 second to 10 seconds with 1 kgf/cm 2 to 30 kgf/cm 2 .

14 . The method of claim 13 , wherein the method further comprises secondarily compressing the structure at 60° C. to 110° C. for 30 seconds to 180 seconds, with 1 kgf/cm 2 to 30 kgf/cm 2 after the compressing the structure and injecting an electrolyte.

15 . The method of claim 13 , wherein the separator comprises a porous substrate and a porous adhesive layer disposed on one surface or both surfaces of the porous substrate and including an acryl-based copolymer including a (meth)acrylate-based monomer-derived repeating unit.

16 . The method of claim 15 , wherein the acryl-based copolymer further comprises an acetate group-containing monomer-derived repeating unit.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Kim Kee Wook
• Kim Nam Hyo
• Yun Hyo Sang
• Chun Ji Hyun

Classifications

• C08J2433/10

  Homopolymers or copolymers of methacrylic acid esters · CPC title

• C09D127/16

  Homopolymers or copolymers of vinylidene fluoride · CPC title

• H01M4/0404

  by coating on electrode collectors · CPC title

• H01M10/058 Primary

  Construction or manufacture · CPC title

• H01M2004/021

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