NONAQUEOUS ELECTROLYTE SECONDARY BATTERY SEPARATOR

• US 20180254453A1
• Filed: 03/02/2018
• Published: 09/06/2018
• Est. Priority Date: 03/03/2017
• Status: Abandoned Application

• Current Assignee: Sumitomo Chemical Company Limited
• Original Assignee: Sumitomo Chemical Company Limited
• Inventors: YOSHIMARU, Chikae, HARA, Syusaku, MURAKAMI, Chikara
• Application Number:
  US15/910,215
• Publication Number:
  US 20180254453A1
• Time in Patent Office: Days
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 50/406 Moulding; Embossing; Cutting
• CPC Class Codes: H01M 50/414 Synthetic resins, e.g. thermoplastics or thermosetting resins
• CPC Class Codes: H01M 50/417 Polyolefins
• CPC Class Codes: H01M 50/451 comprising layers of only organic material and layers containing inorganic material
• CPC Class Codes: H01M 50/489 Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

As a nonaqueous electrolyte secondary battery separator that is excellent in initial battery resistance characteristic of a nonaqueous electrolyte secondary battery including the nonaqueous electrolyte secondary battery separator, provided is a nonaqueous electrolyte secondary battery separator including: a polyolefin porous film, the polyolefin porous film having an internal fractal dimension of 1.75 to 1.91, the internal fractal dimension being measured, by a box counting method, in accordance with a continuous image of the polyolefin porous film which continuous image is formed so as to extend from a surface of the polyolefin porous film in an internal thickness direction of the polyolefin porous film, and in which continuous image a void part and a resin part of the polyolefin porous film are shown at respective two gray levels.

Claims

1. A nonaqueous electrolyte secondary battery separator comprising:

a polyolefin porous film,

the polyolefin porous film having an internal fractal dimension of 1.75 to 1.91, the internal fractal dimension being measured, by a box counting method, in accordance with a continuous image of the polyolefin porous film which continuous image is obtained by FIB-SEM measurement at a magnification of 6500 times and by image analysis, in which continuous image the polyolefin porous film has (i) a size of 256 pix×

256 pix in a surface direction thereof and (ii) a thickness corresponding to a thickness of the polyolefin porous film, where 1 pix is 19.2 nm, which continuous image is formed so as to extend from a surface of the polyolefin porous film in an internal thickness direction of the polyolefin porous film, and in which continuous image a void part and a resin part of the polyolefin porous film are shown at respective two gray levels.

2. The nonaqueous electrolyte secondary battery separator as set forth in claim 1, wherein the internal fractal dimension is 1.77 to 1.90.

3. A nonaqueous electrolyte secondary battery laminated separator comprising:

a nonaqueous electrolyte secondary battery separator recited in claim 1; and

an insulating porous layer.

4. A nonaqueous electrolyte secondary battery member comprising:

a positive electrode;

a nonaqueous electrolyte secondary battery separator recited in claim 1; and

a negative electrode, the positive electrode, the nonaqueous electrolyte secondary battery separator, and the negative electrode being provided in this order.

5. A nonaqueous electrolyte secondary battery comprising:

a nonaqueous electrolyte secondary battery separator recited in claim 1.

6. A nonaqueous electrolyte secondary battery member comprising:

a positive electrode;

a nonaqueous electrolyte secondary battery laminated separator recited in claim 3; and

a negative electrode, the positive electrode, the nonaqueous electrolyte secondary battery laminated separator, and the negative electrode being provided in this order.

7. A nonaqueous electrolyte secondary battery comprising:

a nonaqueous electrolyte secondary battery laminated separator recited in claim 3.