Method for fabricating a nonaqueous electrolyte secondary battery

Patent metadata

Field	Value
Publication number	US-9705159-B2
Application number	US-201414341630-A
Country	US
Kind code	B2
Filing date	Jul 25, 2014
Priority date	Aug 9, 2007
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

Abstract

A nonaqueous electrolyte secondary battery includes: a positive electrode 4 including a positive electrode current collector and a positive electrode mixture layer containing a positive electrode active material and a binder, the positive electrode mixture layer being provided on the positive electrode current collector; a negative electrode 5 ; a porous insulating layer 6 interposed between the positive electrode 4 and the negative electrode 5 ; and a nonaqueous electrolyte. The positive electrode 4 has a tensile extension percentage of equal to or higher than 3.0%. The positive electrode current collector is made of aluminum containing iron. In this manner, the tensile extension percentage of the positive electrode is increased without a decrease in capacity of the nonaqueous electrolyte secondary battery. Accordingly, even when the nonaqueous electrolyte secondary battery is destroyed by crush, occurrence of short-circuit in the nonaqueous electrolyte secondary battery can be suppressed.

First claim

The invention claimed is:

1. A method for fabricating a nonaqueous electrolyte secondary battery including: a positive electrode including a positive electrode current collector and a positive electrode mixture layer containing a positive electrode active material and a binder, the positive electrode mixture layer being provided on the positive electrode current collector; a negative electrode; a porous insulating layer interposed between the positive electrode and the negative electrode; and a nonaqueous electrolyte, the method comprising the steps of:
(a) preparing the positive electrode;
(b) preparing the negative electrode;
(c) either winding or stacking the positive electrode and the negative electrode with the porous insulating layer interposed therebetween, after steps (a) and (b), wherein
step (a) includes the steps of:
(a1) coating the positive electrode current collector with positive electrode material mixture slurry containing the positive electrode active material and the binder, and drying the slurry;
(a2) rolling the positive electrode current collector coated with the dried positive electrode material mixture slurry, thereby forming the positive electrode having a given thickness; and
(a3) performing heat treatment on the positive electrode at a given temperature, after step (a2), with hot air subjected to low humidity treatment, wherein

in step (a3), the given temperature is in the range from 250° C. to 350° C., both inclusive, and the heat treatment is performed in a period of time ranging from 10 seconds to 120 seconds, both inclusive.

2. The method of claim 1 , wherein the given temperature is lower than a decomposition temperature of the binder.

3. The method of claim 1 , wherein an amount of the binder contained in the positive electrode material mixture slurry is in the range from 3.0 vol % to 6.0 vol %, both inclusive, with respect to 100.0 vol % of the positive electrode active material.

4. A method for fabricating a nonaqueous electrolyte secondary battery including: a positive electrode including: a positive electrode current collector and a positive electrode mixture layer containing a positive electrode active material and a binder, the positive electrode mixture layer being provided on the positive electrode current collector; a negative electrode; a porous insulating layer interposed between the positive electrode and the negative electrode; and a nonaqueous electrolyte, the method comprising the steps of:
(a) preparing the positive electrode;
(b) preparing the negative electrode;
(c) either winding or stacking the positive electrode and the negative electrode with the porous insulating layer interposed therebetween, after steps (a) and (b), wherein
step (a) includes the steps of:
(a1) coating the positive electrode current collector with positive electrode material mixture slurry containing the positive electrode active material and the binder, and drying the slurry;
(a2) rolling the positive electrode current collector coated with the dried positive electrode material mixture slurry, thereby forming the positive electrode having a given thickness; and
(a3) performing heat treatment on the positive electrode after step (a2) by bringing a heated roll heated at the given temperature into contact with the positive electrode,

wherein in step (a3), the given temperature is 280° C., and
the heat treatment is performed in a period of time equal to or less than 10 seconds.

5. A method for fabricating a nonaqueous electrolyte secondary battery including: a positive electrode including: a positive electrode current collector and a positive electrode mixture layer containing a positive electrode active material and a binder, the positive electrode mixture layer being provided on the positive electrode current collector; a negative electrode; a porous insulating layer interposed between the positive electrode and the negative electrode; and a nonaqueous electrolyte, the method comprising the steps of:
(a) preparing the positive electrode;
(b) preparing the negative electrode;
(c) either winding or stacking the positive electrode and the negative electrode with the porous insulating layer interposed therebetween, after steps (a) and (b), wherein
step (a) includes the steps of:
(a1) coating the positive electrode current collector with positive electrode material mixture slurry containing the positive electrode active material and the binder, and drying the slurry;
(a2) rolling the positive electrode current collector coated with the dried positive electrode material mixture slurry, thereby forming the positive electrode having a given thickness; and
(a3) performing heat treatment on the positive electrode after step (a2) by bringing a heated roll heated at the given temperature into contact with the positive electrode,

wherein in step (a3), the given temperature is in the range from 250° C. to 350° C., both inclusive, and
the heat treatment is performed in a period of time which is less than 10 seconds.

6. A method for fabricating a nonaqueous electrolyte secondary battery including: a positive electrode including: a positive electrode current collector and a positive electrode mixture layer containing a positive electrode active material and a binder, the positive electrode mixture layer being provided on the positive electrode current collector; a negative electrode; a porous insulating layer interposed between the positive electrode and the negative electrode; and a nonaqueous electrolyte, the method comprising the steps of:
(a) preparing the positive electrode;
(b) preparing the negative electrode;
(c) either winding or stacking the positive electrode and the negative electrode with the porous insulating layer interposed therebetween, after steps (a) and (b), wherein
step (a) includes the steps of:
(a1) coating the positive electrode current collector with positive electrode material mixture slurry containing the positive electrode active material and the binder, and drying the slurry;
(a2) rolling the positive electrode current collector coated with the dried positive electrode material mixture slurry, thereby forming the positive electrode having a given thickness; and
(a3) performing heat treatment on the positive electrode after step (a2) by bringing a heated roll heated at the given temperature into contact with the positive electrode,

wherein in step (a3), the given temperature is in the range from 220° C. to 250° C., both inclusive, and
the heat treatment is performed in a period of time which is less than 2 minutes.

7. A method for fabricating a nonaqueous electrolyte secondary battery including: a positive electrode including: a positive electrode current collector and a positive electrode mixture layer containing a positive electrode active material and a binder, the positive electrode mixture layer being provided on the positive electrode current collector; a negative electrode; a porous insulating layer interposed between the positive electrode and the negative electrode; and a nonaqueous electrolyte, the method comprising the steps of:
(a) preparing the positive electrode;
(b) preparing the negative electrode;
(c) either winding or stacking the positive electrode and the negative electrode with the porous insulating layer interposed therebetween, after steps (a) and (b), wherein
step (a) includes the steps of:
(a1) coating the positive electrode current collector with positive electrode material mixture slurry containing the positive electrode active material and the binder, and drying the slurry;
(a2) rolling the positive electrode current collector coated with the dried positive electrode material mixture slurry, thereby forming the positive electrode having a given thickness; and
(a3) per

Assignees

• Panasonic Corp
• Panasonic Ip Man Co Ltd

Inventors

• Muraoka Yoshiyuki
• Watanabe Kozo
• Inoue Kaoru
• Okada Yukihiro

Classifications

• H01M50/489

  Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties · CPC title

• H01M4/661

  Metal or alloys, e.g. alloy coatings (H01M4/669 take precedence) · CPC title

• H01M4/66

  Selection of materials · CPC title

• Y10T29/49115

  including coating or impregnating · CPC title

• H01M10/0431

  Cells with wound or folded electrodes (H01M10/045 takes precedence) · CPC title