Method for producing electrochemical device

Patent metadata

Field	Value
Publication number	US-9865853-B2
Application number	US-201213425599-A
Country	US
Kind code	B2
Filing date	Mar 21, 2012
Priority date	May 10, 2007
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

An electrochemical device of the present invention includes a positive electrode, a negative electrode, a non-aqueous electrolyte, and a separator. The separator includes a first porous layer composed mainly of a thermoplastic resin and a second porous layer composed mainly of insulating particles with a heat-resistant temperature of 150° C. or higher. The first porous layer is disposed to face the negative electrode.

First claim

The invention claimed is:

1. A method for manufacturing an electrochemical device comprising a spiral electrode body that comprises a positive electrode, a negative electrode, and a pair of separators, each of which includes a first porous layer having a shutdown function and a second porous layer integrated with the first porous layer,
the method comprising:
lapping the pair of separators one over the other so that the second porous layers of the respective separators are arranged inside, and wrapping the lapped separators around a winding shaft with the first porous layer facing the winding shaft;
winding the positive electrode and the negative electrode with the pair of separators to form the spiral electrode body; and
removing the wound electrode body from the winding shaft,
wherein
the first porous layer of each of the separators contains 50 vol % or more of a thermoplastic resin and the second porous layer of each of the separators contains an insulating filler with a heat-resistant temperature of 150° C. or higher and an organic binder for binding insulating filler particles, a content of the insulating filler in the second porous layer being 50 vol % or more.

2. The method according to claim 1 , wherein a coefficient of static friction between the first porous layer of each of the separators and the winding shaft is 0.5 or less.

3. The method according to claim 1 , wherein a coefficient of static friction between the first porous layer of each of the separators and the winding shaft is 0.05 or more.

4. The method according to claim 1 , wherein a material of the winding shaft is stainless steel or ceramic-coated stainless steel.

5. The method according to claim 1 , wherein a thermal shrinkage ratio of the separator is 5% or less at 150° C.

6. The method according to claim 1 , wherein the insulating filler is inorganic particles.

7. The method according to claim 1 , wherein the first porous layer of each of the separators is a microporous film, and the microporous film is a polyolefin microporous film or a laminated porous film including a thermoplastic resin with a melting point of 80° C. to 140° C. and a thermoplastic resin with a melting point of higher than 140° C.

8. The method according to claim 1 , wherein the thermoplastic resin includes polyethylene having a molecular weight of 2000 to 100000.

9. The method according to claim 1 , wherein a content of the insulating filler in the second porous layer of each of the separators is 70 vol % or more.

10. The method according to claim 1 , wherein a shutdown temperature determined by a change in internal resistance with temperature is 127° C. to 150° C.

11. The method according to claim 1 , wherein the first porous layer of each of the separators contains, as the thermoplastic resin, a resin having a melting point of 100 to 140° C. and a melt viscosity of 1000 mPa·s or more at 140° C.

12. The method according to claim 1 , wherein the first porous layer of each of the separators contains, as the thermoplastic resin, a resin having a melting point of 100 to 140° C. and a melt viscosity of 1000000 mPa·s or less at 140° C.

13. The method according to claim 1 , wherein the positive electrode is arranged inside the pair of separators.

14. The method according to claim 1 , wherein X is more than 5 μm and 30 μm or less, Y is 1 μm or more and 10 μm or less, and X/Y is more than ½ and 10 or less, where X (μm) represents a thickness of the first porous layer and Y (μm) represents a thickness of the second porous layer of each of the separators.

15. The method according to claim 1 , wherein each of the separators has the first porous layer formed on only one side of the second porous layer.

16. A method for manufacturing an electrochemical device comprising a spiral electrode body that comprises a positive electrode and a negative electrode, each having an active material containing layer, and a pair of separators, each of which includes a first porous layer having a shutdown function and a second porous layer integrated with the first porous layer, and has different friction coefficients on both sides,
the method comprising:
lapping the pair of separators one over the other so that higher friction coefficient sides of the respective separators are arranged inside, and wrapping the lapped separators around a winding shaft with a lower friction coefficient side facing the winding shaft;
forming the spiral electrode body by winding the positive electrode and the negative electrode with the pair of separators; and
removing the wound electrode body from the winding shaft,
wherein the first porous layer of each of the separators contains 50 vol % or more of a thermoplastic resin and the second porous layer of each of the separators contains an insulating filler with a heat-resistant temperature of 150° C. or higher and an organic binder for binding insulating filler particles, a content of the insulating filler in the second porous layer being 50 vol % or more.

17. The method according to claim 16 , wherein X is more than 5 μm and 30 μM or less, Y is 1 μm or more and 10 μm or less, and X/Y is more than ½ and 10 or less, where X (μm) represents a thickness of the first porous layer and Y (μm) represents a thickness of the second porous layer of each of the separators.

Assignees

• Katayama Hideaki
• Abe Toshihiro
• Matsumoto Nobuaki
• Maxell Holdings Ltd

Inventors

• Katayama Hideaki
• Abe Toshihiro
• Matsumoto Nobuaki

Classifications

• H01M10/052 Primary

  Li-accumulators · CPC title

• H01M50/417

  Polyolefins · CPC title

• H01M50/434

  Ceramics · CPC title

• H01M50/491

  Porosity · CPC title

• 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