Positive electrode for lithium secondary battery, winding element for lithium secondary battery, and lithium secondary battery

Patent metadata

Field	Value
Publication number	US-2021028462-A1
Application number	US-201715999103-A
Country	US
Kind code	A1
Filing date	Feb 16, 2017
Priority date	Feb 19, 2016
Publication date	Jan 28, 2021
Grant date	—

Abstract

Disclosed are a positive electrode for a lithium secondary battery, a winding element for a lithium secondary battery, and a lithium secondary battery, wherein the positive electrode includes a positive active material and a mixing binder including a first binder, a second binder, and a third binder, the first binder includes at least one selected from copolymers including polyvinylidene fluoride, acid-modified polyvinylidene fluoride, and acid-modified polyvinylidene fluoride, and the mixing binder includes the first binder at a proportion of 30 wt % to 60 wt % relative to the total weight of the mixing binder, and has a tensile modulus of 200 MPa to 600 MPa.

First claim

1 . A positive electrode for a lithium secondary battery, comprising
a positive active material; and a mixing binder including a first binder, a second binder, and a third binder, the first binder comprises at least one selected from copolymers comprising polyvinylidene fluoride, acid-modified polyvinylidene fluoride, and acid-modified polyvinylidene fluoride, and the mixing binder comprises the first binder at a proportion of 30 to 60 wt % relative to the total weight of the mixing binder, and has a tensile modulus of 200 MPa to 600 MPa.

2 . The positive electrode for a lithium secondary battery of claim 1 , wherein the copolymer comprising the acid-modified polyvinylidene fluoride comprises at least one monomer selected from the group consisting of tetrafluoroethylene, hexafluoro propylene, and chlorotrifluoroethylene.

3 . The positive electrode for a lithium secondary battery of claim 1 , wherein the second binder is a hydrogenated acrylonitrile butadiene rubber.

4 . The positive electrode for a lithium secondary battery of claim 1 , wherein the mixing binder comprises the second binder at a proportion of 10 to 40 wt % relative to the total weight of the mixing binder.

5 . The positive electrode for a lithium secondary battery of claim 1 , wherein the third binder comprises a copolymer comprising vinylidene fluoride.

6 . The positive electrode for a lithium secondary battery of claim 1 , wherein the third binder has a tensile modulus of 150 MPa to 600 MPa.

7 . The positive electrode for a lithium secondary battery of claim 5 , wherein the copolymer comprising the vinylidene fluoride is at least one selected from the group consisting of a vinylidene fluoride-tetrafluoroethylene copolymer, a vinylidene fluoride-hexafluoro propylene copolymer, a vinylidene fluoride-chlorotrifluoroethylene copolymer, a vinylidene fluoride-tetrafluoroethylene-hexafluoro propylene copolymer, a vinylidene fluoride-acrylate copolymer, a vinylidene fluoride-hexafluoro propylene-acrylate copolymer, a vinylidene fluoride-tetrafluoroethylene-acrylate copolymer, and a vinylidene fluoride-tetrafluoroethylene-hexafluoro propylene-acrylate copolymer.

8 . A winding element for a lithium secondary battery comprising the positive electrode of claim 1 .

9 . A lithium secondary battery comprising the winding element for a lithium secondary battery of claim 8 .

Assignees

• Samsung Sdi Co Ltd

Inventors

• Nomura Keisuke
• Fukahori Hironobu

Classifications

• H01M4/623 Primary

  fluorinated polymers · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M10/0525

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

• H01M4/13

  Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof · CPC title

• H01M4/62

  Selection of inactive substances as ingredients for active masses, e.g. binders, fillers · CPC title