Lithium-ion secondary battery separator

Patent metadata

Field	Value
Publication number	US-9601737-B2
Application number	US-201314411274-A
Country	US
Kind code	B2
Filing date	May 21, 2013
Priority date	Jun 29, 2012
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

A lithium-ion secondary battery separator resolves defects of a non-woven fabric separator which is not suitable for use in such a battery. The separator is thin and does not short-circuit and has excellent electrolyte retainability and rate characteristics. The separator includes a composite of a non-woven fabric having a basis weight of 2 to 20 g/m 2 formed from fibers of a thermoplastic material having an average fiber diameter of 5 to 40 μm and ultra-microfibers having an average fiber diameter of 1 μm or less in an amount of ⅓ to 3 times the mass of the non-woven fabric. The composite has a thickness of 10 to 40 μm after heat-pressing treatment under conditions that the non-woven fabric has a glossiness (JIS Z 8741) measured at 60° in the range of 3 to 30 and a thickness of 10 to 40.

First claim

The invention claimed is:

1. A lithium-ion secondary battery separator comprising a composite of a non-woven fabric having a basis weight of 2 to 20 g/m 2 formed from fibers of a thermoplastic material having an average fiber diameter of 5 to 40 μm and ultra-microfibers having an average fiber diameter of 1 μm or less in an amount of ⅓ to 3 times the mass of the non-woven fabric, the composite having a thickness of 10 to 40 μm after being subjected to a heat-pressing treatment carried out under such conditions that the non-woven fabric has a glossiness measured at 60° in accordance with JIS standard (JIS Z 8741) in the range of 3 to 30 and a thickness of 10 to 40 μm if only the non-woven fabric is subjected to the heat-pressing treatment.

2. The lithium-ion secondary battery separator according to claim 1 , wherein the thermoplastic material is at least one type of thermoplastic material selected from the group consisting of polyolefins, polyesters, polyamides, polyimides, polyacrylonitriles and polyvinyl alcohols.

3. The lithium-ion secondary battery separator according to claim 2 , wherein the non-woven fabric is formed from core-in-sheath type composite fibers containing a thermoplastic material as the sheath component or the core-in-sheath type composite fibers and other fibers of thermoplastic materials.

4. The lithium-ion secondary battery separator according to claim 2 , wherein the heat pressing treatment is carried out at a temperature of 100 to 300° C. and a pressure of 0.5 to 3 MPa.

5. The lithium-ion secondary battery separator according to claim 1 , wherein the non-woven fabric is formed from core-in-sheath type composite fibers containing a thermoplastic material as the sheath component or the core-in-sheath type composite fibers and other fibers of thermoplastic materials.

6. The lithium-ion secondary battery separator according to claim 5 , wherein the heat pressing treatment is carried out at a temperature of 100 to 300° C. and a pressure of 0.5 to 3 MPa.

7. The lithium-ion secondary battery separator according to claim 5 , wherein the core component and sheath component of the core-in-sheath type composite fibers are polypropylene and polyethylene, respectively.

8. The lithium-ion secondary battery separator according to claim 7 , wherein the heat pressing treatment is carried out at a temperature of 100 to 300° C. and a pressure of 0.5 to 3 MPa.

9. The lithium-ion secondary battery separator according to claim 1 , wherein the heat pressing treatment is carried out at a temperature of 100 to 300° C. and a pressure of 0.5 to 3 MPa.

10. The lithium-ion secondary battery separator according to claim 1 , wherein the composite is laminated and integrated.

11. The lithium-ion secondary battery separator according to claim 1 , wherein the composite is the non-woven fabric and the ultra-microfibers in an amount of ½ to 3 times the mass of the non-woven fabric.

12. A lithium-ion secondary battery separator comprising a heat-pressed composite of a non-woven fabric combined with ultra-microfibers, the heat-pressed composite having a thickness of 10 to 45 μm, the non-woven fabric having a basis weight of 2 to 20 g/m 2 and being formed from fibers of a thermoplastic material having an average fiber diameter of 5 to 40 μm and a glossiness measured at 60° in accordance with JIS standard (JIS Z 8741) in the range of 3 to 30, the ultra-microfibers having an average fiber diameter of 1 μm or less and being present in an amount of ⅓ to 3 times the mass of the non-woven fabric.

13. The lithium-ion secondary battery separator according to claim 12 , wherein the thermoplastic material is at least one type of thermoplastic material selected from the group consisting of polyolefins, polyesters, polyamides, polyimides, polyacrylonitriles and polyvinyl alcohols.

14. The lithium-ion secondary battery separator according to claim 12 , wherein the non-woven fabric is formed from core-in-sheath type composite fibers containing a thermoplastic material as the sheath component or the core-in-sheath type composite fibers and other fibers of thermoplastic materials.

15. The lithium-ion secondary battery separator according to claim 14 , wherein the core component and sheath component of the core-in-sheath type composite fibers are polypropylene and polyethylene, respectively.

16. The lithium-ion secondary battery separator according to claim 12 , wherein the composite is a laminated and integrated composite.

17. The lithium-ion secondary battery separator according to claim 12 , wherein the ultra-microfibers are present in an amount of ½ to 3 times the mass of the non-woven fabric.

Assignees

• Jx Nippon Oil & Energy Corp

Inventors

• Konishi Hiroaki
• Omaru Atsuo
• Tsuruta Yuji

Classifications

• H01M50/451

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

• H01M50/414

  Synthetic resins, e.g. thermoplastics or thermosetting resins · CPC title

• D01F8/06

  with at least one polyolefin as constituent · CPC title

• H01M2/1686

  Electricity · mapped topic