Nonaqueous electrolyte secondary battery laminated separator

Patent metadata

Field	Value
Publication number	US-11695186-B2
Application number	US-202016848883-A
Country	US
Kind code	B2
Filing date	Apr 15, 2020
Priority date	Apr 16, 2019
Publication date	Jul 4, 2023
Grant date	Jul 4, 2023

Abstract

The present invention provides a nonaqueous electrolyte secondary battery laminated separator which improves a long-term battery characteristic of a nonaqueous electrolyte secondary battery. According to the nonaqueous electrolyte secondary battery laminated separator in accordance with an aspect of the present invention, an absolute value of a difference between (i) a standard deviation of whiteness index in one outermost layer and (ii) a standard deviation of whiteness index of the other outermost layer is greater than 0.01 and is 0.60 or less, and a greater one of the two standard deviation values of whiteness index is 0.06 or more and 0.91 or less.

First claim

The invention claimed is:

1. A nonaqueous electrolyte secondary battery laminated separator comprising:
a polyolefin porous film; and
a nonaqueous electrolyte secondary battery porous layer which is stacked on one surface or both surfaces of the polyolefin porous film,
an absolute value of a difference between (i) a standard deviation value of a whiteness index defined in E313 of the American Standards Test Methods in a first outermost layer of said nonaqueous electrolyte secondary battery laminated separator and (ii) a standard deviation value of the whiteness index of a second outermost layer of said nonaqueous electrolyte secondary battery laminated separator being greater than 0.01 and being 0.60 or less,
a greater one of the standard deviation value of the whiteness index in the first outermost layer and the standard deviation value of the whiteness index in the second outermost layer being 0.06 or more and 0.91 or less.

2. The nonaqueous electrolyte secondary battery laminated separator as set forth in claim 1 , wherein:
the first outermost layer is the polyolefin porous film; and
the second outermost layer is the nonaqueous electrolyte secondary battery porous layer.

3. The nonaqueous electrolyte secondary battery laminated separator as set forth in claim 1 , wherein the nonaqueous electrolyte secondary battery porous layer contains one or more resins selected from the group consisting of polyolefin, a (meth)acrylate resin, a fluorine-containing resin, a polyamide resin, a polyester resin, and a water-soluble polymer.

4. The nonaqueous electrolyte secondary battery laminated separator as set forth in claim 1 , wherein the nonaqueous electrolyte secondary battery porous layer contains a polyamide resin.

5. The nonaqueous electrolyte secondary battery laminated separator as set forth in claim 4 , wherein the polyamide resin is an aramid resin.

6. The nonaqueous electrolyte secondary battery laminated separator as set forth in claim 5 , wherein the aramid resin is one or more aramid resins selected from the group consisting of poly(paraphenylene terephthalamide), poly(metaphenylene terephthalamide), and a paraphenylene terephthalamide/metaphenylene terephthalamide copolymer.

7. The nonaqueous electrolyte secondary battery laminated separator as set forth in claim 1 , wherein the nonaqueous electrolyte secondary battery porous layer contains a heat-resistant filler.

8. The nonaqueous electrolyte secondary battery laminated separator as set forth in claim 7 , wherein the heat-resistant filler is an inorganic filler.

9. The nonaqueous electrolyte secondary battery laminated separator as set forth in claim 8 , wherein the inorganic filler contains one or more inorganic substances selected from the group consisting of alumina, boehmite, aluminum hydroxide, magnesium hydroxide, magnesium oxide, titanium oxide, and silica.

10. A nonaqueous electrolyte secondary battery comprising a nonaqueous electrolyte secondary battery laminated separator recited in claim 1 .

Assignees

• Sumitomo Chemical Co

Inventors

• Iwata Shizuka

Classifications

• H01M50/451

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

• H01M50/446 Primary

  Composite material consisting of a mixture of organic and inorganic materials · CPC title

• H01M50/489 Primary

  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

• H01M50/417

  Polyolefins · CPC title

• H01M4/62

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