Secondary battery porous membrane, slurry for secondary battery porous membrane, and secondary battery

Patent metadata

Field	Value
Publication number	US-9437856-B2
Application number	US-201113882029-A
Country	US
Kind code	B2
Filing date	Oct 28, 2011
Priority date	Oct 28, 2010
Publication date	Sep 6, 2016
Grant date	Sep 6, 2016

Abstract

To provide a secondary battery porous membrane that has superior heat resistance and flexibility and contributes to improvements in battery cycle characteristics. Also provided is a secondary battery having high cycle characteristics that uses this porous membrane. [Solution] This secondary battery porous membrane contains nonconductive particles and a binder. The binder is characterized by being formed from a polymer containing a nitrile group, a novel group, and a C 4+ straight-chain alkylene structural unit in the same molecule and the nitrile group content in the polymer constituting the binder being 1-25% by mass, with the iodine value of the polymer being 0 mg/100 mg-30 mg/100 mg.

First claim

The invention claimed is:

1. A secondary battery porous membrane comprising a non-conductive particle and a binder; wherein
said binder comprises a polymer including a nitrile group, a hydrophilic group and a linear alkylene structural unit having carbon atoms of 4 or more in a same molecule,
a content ratio of said nitrile group in the polymer constituting said binder is 1 to 25 wt % and an iodine value of said polymer is 0 mg/100 mg or more and 30 mg/100 mg or less, and
a content ratio of said hydrophilic group in the polymer constituting said binder is 1 to 6 wt %.

2. The secondary battery porous membrane as set forth in claim 1 , wherein a content ratio of said linear alkylene structural unit in the polymer constituting said binder is 50 to 98 wt %.

3. The secondary battery porous membrane as set forth in claim 1 , wherein the polymer constituting said binder is hydrogenated acrylonitrile.butadiene copolymer.

4. The secondary battery porous membrane as set forth in claim 1 , wherein said hydrophilic group is selected from the group consisting of a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, hydroxyl group and salts thereof.

5. The secondary battery porous membrane as set forth in claim 1 , wherein a content ratio of said non-conductive particle in a total amount of a solid portion constituting said porous membrane is 70 to 97 wt %, and a content ratio of said binder is 0.5 to 15 wt %.

6. The secondary battery porous membrane as set forth in claim 1 , wherein an average particle size of said non-conductive particle is 0.1 to 20 μm, and a ratio of particles in terms of number within a range of an aspect ratio between 3 to 100 is 50% or more.

7. An electrode for a secondary battery wherein an electrode active material layer including a binder for an electrode mixed layer and electrode active materials is formed by adhering to a current collector, and a surface of the electrode active layer is formed by stacking the porous membrane set forth in claim 1 .

8. A separator for a secondary battery wherein said porous membrane set forth in claim 1 is stacked on an organic separator.

9. A secondary battery including a positive electrode, a negative electrode, a separator and an electrolytic solution wherein at least one of said positive electrode, said negative electrode and the separator is stacked with the porous membrane set forth in claim 1 .

10. The secondary battery porous membrane as set forth in claim 2 , wherein the polymer constituting said binder is hydrogenated acrylonitrile.butadiene copolymer.

11. The secondary battery porous membrane as set forth in claim 2 , wherein said hydrophilic group is selected from the group consisting of a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, hydroxyl group and salts thereof.

12. The secondary battery porous membrane as set forth in claim 3 , wherein said hydrophilic group is selected from the group consisting of a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, hydroxyl group and salts thereof.

13. The secondary battery porous membrane as set forth in claim 2 , wherein a content ratio of said non-conductive particle in a total amount of a solid portion constituting said porous membrane is 70 to 97 wt %, and a content ratio of said binder is 0.5 to 15 wt %.

14. A slurry for the secondary battery porous membrane comprising a non-conductive particle, a binder and a dispersion medium; wherein
said binder comprises a polymer including a nitrile group, a hydrophilic group and a linear alkylene structural unit having carbon atoms of 4 or more in a same molecule,
a content ratio of said nitrile group in the polymer constituting said binder is 1 to 25 wt % and an iodine value of said polymer is 0 mg/100 mg or more and 30 mg/100 mg or less, and
a content ratio of said hydrophilic group in the polymer constituting said binder is 1 to 6 wt %.

15. A production method of the secondary battery porous membrane comprising a step of coating the slurry for the porous membrane set forth in claim 14 to a substrate, and a step of drying.

Assignees

• Ishii Takuya
• Kaneda Takuya
• Zeon Corp

Inventors

• Ishii Takuya
• Kaneda Takuya

Classifications

• H01M50/403 Primary

  Manufacturing processes of separators, membranes or diaphragms · CPC title

• H01M50/451

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

• H01M50/42

  Acrylic resins · CPC title

• H01M50/417

  Polyolefins · CPC title

• H01M50/491

  Porosity · CPC title