Separator and battery

Patent metadata

Field	Value
Publication number	US-10312491-B2
Application number	US-95963810-A
Country	US
Kind code	B2
Filing date	Dec 3, 2010
Priority date	Dec 4, 2009
Publication date	Jun 4, 2019
Grant date	Jun 4, 2019

Abstract

A separator includes a first layer that has a first principal face and a second principal face, and a second layer that is formed on at least one of the first principal face and the second principal face. The first layer is a microporous membrane including a first polymer resin, and the second layer is a microporous membrane including inorganic particles having an electrically insulating property and a second polymer resin.

First claim

The application is claimed as follows:

1. A separator comprising:
a first resin layer having a first principal face and a second principal face; and
a second resin layer provided on at least one of the first principal face and the second principal face;
wherein the second resin layer includes inorganic particles, and a volume fraction of the inorganic particles in the second resin layer is equal to or greater than 60 vol % and equal to or lower than 90 vol %,
wherein an average particle diameter D20 of the inorganic particles is larger than an average pore diameter of pores opening onto a surface of the first resin layer, and the average pore diameter of the pores ranges from 0.03 μm to 0.10 μm,
wherein an average particle diameter D20 of the inorganic particles of the second resin layer ranges from 0.13 μm to 0.21 μm,
wherein the average particle diameter D90 of the inorganic particles of the second resin layer ranges from 2.00 μm to 5.00 μm and is greater than the average particle diameter D20,
wherein the second resin layer includes one or more of materials selected from the group consisting of polyvinylidene fluoride, polyhexafluoropropylene, polysiloxane, polyacrylic acid, polymethacrylate and nitrile butadiene rubber,
wherein a difference between air permeability of the separator and air permeability of the first layer is equal to or less than 60 sec/100 ml, and
wherein the second resin layer comprises fibrils having the average diameter of equal to or less than 1 μm.

2. The separator according to claim 1 , wherein an air-permeability rising rate of air permeability at a time when pressure is applied to the separator for two minutes at 60° C. under 50 kgf/cm 2 with respect to air permeability before the pressure load is equal to or lower than 35%.

3. The separator according to claim 1 , wherein an average membrane thickness of the first layer is equal to or greater than 10.0 μm and less than 30.0 μm.

4. The separator according to claim 1 , wherein an average particle diameter D90 of the inorganic particles is equal to or less than ⅓ of the membrane thickness of the first layer.

5. The separator according to claim 1 , wherein an area density per a unit area of the second resin layer is equal to or greater than 0.2 mg/cm 2 and equal to or less than 1.8 mg/cm 2 .

6. A battery comprising:
a positive electrode;
a negative electrode;
an electrolyte; and
a separator,
wherein the separator includes
a first resin layer having a first principal face and a second principal face and
a second resin layer provided on at least one of the first principal face and the second principal face;

wherein the second resin layer includes inorganic particles, and a volume fraction of the inorganic particles in the second resin layer is equal to or greater than 60 vol % and equal to or lower than 90 vol %,
wherein an average particle diameter D20 of the inorganic particles is larger than an average pore diameter of pores opening onto a surface of the first resin layer, and the average pore diameter of the pores ranges from 0.03 μm to 0.10 μm,
wherein an average particle diameter D20 of the inorganic particles of the second resin layer ranges from 0.13 μm to 0.21 μm,
wherein the average particle diameter D90 of the inorganic particles of the second resin layer ranges from 2.00 μm to 5.00 μm and is greater than the average particle diameter D20,
wherein the second resin layer includes one or more of materials selected from the group consisting of polyvinylidene fluoride, polyhexafluoropropylene, polysiloxane, polyacrylic acid, polymethacrylate and nitrile butadiene rubber,
wherein a difference between air permeability of the separator and air permeability of the first layer is equal to or less than 60 sec/100 ml, and
wherein the second resin layer comprises fibrils having the average diameter of equal to or less than 1 μm.

7. The battery according to claim 6 , wherein an open-circuit voltage in a fully-charged state is in the range of 4.2 V to 4.6 V.

8. The battery according to claim 6 , wherein an air-permeability rising rate of air permeability at a time when pressure is applied to the separator for two minutes at 60° C. under 50 kgf/cm 2 with respect to air permeability before the pressure load to the separator is equal to or lower than 35%.

9. The battery according to claim 6 , wherein the positive electrode, the negative electrode and the separator are stacked and wound to constitute a wound electrode body,
an outer end of the separator is exposed on the periphery of the wound electrode body.

10. The battery according to claim 9 , wherein a lead is connected to at least one of outer ends of the positive electrode and the negative electrode.

11. The battery of claim 10 , wherein at least one of outer and inner principal faces of a collector of the positive electrode or the negative electrode is exposed at the at least one of the outer ends of the positive electrode and the negative electrode and the lead is connected to the exposed portion of the collector.

12. The battery according to claim 6 , wherein an area density per unit area of the second resin layer is equal to or greater than 0.2 mg/cm 2 and equal to or less than 1.8 mg/cm 2 .

13. The separator according to claim 1 , wherein the first resin layer includes a first resin having chemical stability that is mixed or copolymerized with polyethylene or polypropylene.

14. The separator according to claim 1 , wherein the second polymer resin includes polyhexafluoropropylene.

15. The separator according to claim 1 , wherein the second resin layers are formed on both of the first principal face and the second principal face of the first resin layer.

16. The separator according to claim 1 , wherein the second resin layer has a fibrillated mesh-shaped structure with the inorganic particles being separately dispersed.

17. The separator according to claim 1 , wherein the second resin layer includes one or more of materials selected from the group consisting of polysiloxane, polyvinyl alcohol, polyacrylic acid, styrene-butadiene rubber and nitrile butadiene rubber.

18. The separator according to claim 1 , wherein the inorganic particles includes at least one of alumina, silica, zirconia and titania.

19. The battery according to claim 6 , wherein the second resin layer includes one or more of materials selected from the group consisting of polysiloxane, polyvinyl alcohol, polyacrylic acid, styrene-butadiene rubber and nitrile butadiene rubber.

20. The battery according to claim 6 , wherein the volume fraction of the inorganic particles in the second resin layer is 82 vol % or more.

21. The battery according to claim 6 , wherein the inorganic particles includes at least one of alumina, silica, zirconia and titania.

22. An electronic apparatus comprising the battery according to claim 1 .

23. The separator according to claim 1 , wherein the average pore diameter of the pores ranges from 0.03 μm to 0.05 μm.

24. The battery according to claim 6 , wherein the average pore diameter of the pores ranges from 0.03 μm to 0.05 μm.

Assignees

• Chiba Kazuki
• Kajita Atsushi
• Teshima Yukako
• Hayashi Masatake
• Murata Manufacturing Co

Inventors

• Chiba Kazuki
• Kajita Atsushi
• Teshima Yukako
• Hayashi Masatake

Classifications

• H01M10/0431 Primary

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

• H01M50/451

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

• H01M50/417

  Polyolefins · CPC title

• H01M50/426

  Fluorocarbon polymers · CPC title

• H01M50/491

  Porosity · CPC title