Multilayer microporous separators for lithium ion secondary batteries and related methods

Patent metadata

Field	Value
Publication number	US-2016149182-A1
Application number	US-201514950625-A
Country	US
Kind code	A1
Filing date	Nov 24, 2015
Priority date	Nov 26, 2014
Publication date	May 26, 2016
Grant date	—

Abstract

An improved multilayer laminated microporous battery separator for a lithium ion secondary battery, and/or a method of making or using this separator is provided. The preferred inventive dry process separator is a tri-layer laminated Polypropylene/Polyethylene/Polypropylene microporous membrane with a thickness range of 12 μm to 30 μm having improved puncture strength and low electrical resistance for improved cycling and charge performance in a lithium ion battery. In addition, the preferred inventive separator's or membrane's low Electrical Resistance and high porosity provides superior charge rate performance in a lithium battery for high power applications.

First claim

We claim:

1 . A novel or improved separator, membrane or base film having at least one of: at least one microporous membrane produced according to a dry stretch process in which a polyolefin resin, mix or blend is extruded to form said membrane, said resin having a melt flow index (MFI) of less than or equal to about 0.8 grams/10 minute; and
wherein said separator having a thickness of greater than or equal to about 12 μm, a porosity in the range of about 35% to about 65%, and an electrical resistance (ER) value of less than or equal to about 1.5 ohm-cm 2 , and optionally wherein the separator is a multilayer or trilayer separator or base film, is made by a dry stretch process, is made by a lamination process, has a puncture strength (PS) of at least 280 gf and has a thickness of at least 12 μm, has a puncture strength (PS) of at least 330 gf and has a thickness of at least 14 μm, has a puncture strength (PS) of at least 350 gf and has a thickness of at least 16 μm, has a porosity of at least 35%, has a porosity of greater than 37%, has a porosity of at least 39%, has a porosity in the range of about 35% to 65%, has a porosity in the range of about 39% to 53%, is especially well suited for power cells, such as used in electric vehicles, has an ER of 1.5 ohm-cm 2 or less, has a porosity of at least 35%, and is adapted for a high C rate charge and discharge, includes at least two microporous polyolefin membranes produced according to a dry process in which a polypropylene resin is extruded to form said membrane, said resin having a melt flow index (MFI) of less than or equal to about 0.8 grams/10 minute, includes at least three microporous polyolefin membranes produced according to a dry process in which a polypropylene resin is extruded to form said membrane, said resin having a melt flow index (MFI) of less than or equal to about 0.8 grams/10 minute, includes at least one polyethylene membrane, includes at least two polypropylene membranes, and/or having an improved puncture strength over prior separators of the same thickness, and combinations thereof.

2 . The separator of claim 1 wherein the separator is a multilayer separator, membrane or base film.

3 . The separator of claim 1 wherein the separator is a trilayer separator, membrane or base film.

4 . The separator of claim 1 wherein the separator is made by a dry stretch process.

5 . The separator of claim 1 wherein the separator is made by a lamination process.

6 . The separator of claim 1 wherein the separator has a puncture strength (PS) of at least 330 gf and has a thickness of at least 14 μm.

7 . The separator of claim 1 wherein the separator has a puncture strength (PS) of at least 350 gf and has a thickness of at least 16 μm.

8 . The separator of claim 1 wherein the separator has a porosity of at least 35%.

9 . The separator of claim 1 wherein the separator has a porosity of greater than 37%.

10 . The separator of claim 1 wherein the separator has a porosity of at least 39%.

11 . The separator of claim 1 wherein the separator has a porosity in the range of about 35% to 65%.

12 . The separator of claim 1 wherein the separator has a porosity in the range of about 39% to 53%.

13 . The separator of claim 1 wherein the separator is especially well suited for power cells, such as used in electric vehicles.

14 . The separator of claim 1 wherein the separator has an ER of 1.5 ohm-cm 2 or less, has a porosity of at least 35%, and is adapted for a high C rate charge and discharge.

15 . The separator of claim 1 wherein the separator includes at least one microporous polyolefin membrane produced according to a dry process in which a polypropylene resin is extruded to form said membrane, said resin having a melt flow index (MFI) of less than or equal to about 0.8 grams/10 minute.

16 . A novel or improved multilayer separator, membrane or base film comprising:
at least one microporous membrane produced according to a dry stretch process in which a polyolefin resin, mix or blend is extruded to form said membrane, said resin having a melt flow index (MFI) of less than or equal to about 0.8 grams/10 minute; and wherein said separator having a thickness of greater than or equal to about 14 μm, a porosity in the range of about 35% to about 65%, and an electrical resistance (ER) value of less than or equal to about 1.5 ohm-cm 2 , and optionally wherein the separator is a trilayer separator or base film, is made by a dry stretch process, is made by a lamination process, has a puncture strength (PS) of at least 330 gf and has a thickness of at least 14 μm, has a puncture strength (PS) of at least 350 gf and has a thickness of at least 16 μm, has a porosity of at least 35%, has a porosity of greater than 37%, has a porosity of at least 39%, has a porosity in the range of about 35% to 65%, has a porosity in the range of about 39% to 53%, is especially well suited for power cells, such as used in electric vehicles, has an ER of 1.5 ohm-cm 2 or less, has a porosity of at least 35%, and is adapted for a high C rate charge and discharge, includes at least two microporous polyolefin membranes produced according to a dry process in which a polypropylene resin is extruded to form said membrane, said resin having a melt flow index (MFI) of less than or equal to about 0.8 grams/10 minute, includes at least three microporous polyolefin membranes produced according to a dry process in which a polypropylene resin is extruded to form said membrane, said resin having a melt flow index (MFI) of less than or equal to about 0.8 grams/10 minute, includes at least one polyethylene membrane, includes at least two polypropylene membranes, and/or having an improved puncture strength over prior separators of the same thickness.

17 . The separator of claim 16 having an improved puncture strength over prior multilayer separators of the same thickness.

18 . The separator of claim 16 being a trilayer separator having an improved puncture strength over prior trilayer separators of the same thickness.

Assignees

• Celgard Llc

Inventors

• Zhang Xiaomin
• Shi Lie
• Paulus William John

Classifications

• H01M50/403 Primary

  Manufacturing processes of separators, membranes or diaphragms · CPC title

• H01M2220/20

  Batteries in motive systems, e.g. vehicle, ship, plane · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M50/457

  comprising three or more layers · CPC title

• H01M50/417

  Polyolefins · CPC title