Method of making a co-extruded, multi-layered battery separator

Patent metadata

Field	Value
Publication number	US-10003058-B2
Application number	US-56091106-A
Country	US
Kind code	B2
Filing date	Nov 17, 2006
Priority date	Nov 17, 2006
Publication date	Jun 19, 2018
Grant date	Jun 19, 2018

Abstract

A battery separator comprises a co-extruded, microporous membrane having at least two layers made of extrudable polymers and having: a uniform thickness defined by a standard deviation of <0.80 microns (μm); or an interply adhesion as defined by a peel strength >60 grams.

First claim

We claim:

1. A method of making a polyolefinic microporous multi-layered co-extruded membrane according to a dry process comprising the steps of:
co-extruding a nonporous polyolefinic multi-layered precursor through an extrusion die with a minimum shear rate of 4 sec −1 and a throughput of 18-100 lbs/hr (8.2-45.4 Kg/hr) per layer, wherein at least two layers of said polyolefinic multi-layered precursor are polymerically dissimilar from one another; and
processing the nonporous polyolefinic multi-layered co-extruded precursor to obtain the microporous polyolefinic multi-layered co-extruded membrane, wherein processing further includes: annealing the nonporous polyolefinic multi-layered microporous polyolefinic multi-layered co-extruded precursor; and stretching the annealed nonporous polyolefinic multi-layered microporous polyolefinic multi-layered co-extruded precursor,
whereby the microporous polyolefinic multi-layered co-extruded membrane has a thickness in the range of 4-50 μm and a uniform thickness defined by a standard deviation of <0.8 μm.

2. The method of claim 1 wherein the shear rate is 8 sec −1 .

3. The method of claim 1 wherein the co-extruding further comprises:
adding a material to at least one layer of said multi-layered precursor.

4. The method of claim 3 wherein said material is selected from the group of materials adapted to: lower the melting temperature of one or more layers; improve the melt integrity of the membrane; improve the strength or toughness of the membrane; improve the antistatic properties of the membrane; improve the surface wettability of the membrane; improve the surface tribology performance of the membrane; improve the processing of one or more layers; improve the flame retardance of the membrane; facilitate nucleation of one or more layers; color one or more layers of the membrane; and combinations thereof.

Assignees

• Call Ronald W
• Fulk Jr C William
• Shi Lie
• Zhang Xiaomin
• Nguyen Khuy V
• Celgard Llc

Inventors

• Call Ronald W
• Fulk Jr C William
• Shi Lie
• Zhang Xiaomin
• Nguyen Khuy V

Classifications

• B29C48/32 Primary

  with annular openings, e.g. for forming tubular articles · CPC title

• B29K2023/0633

  LDPE, i.e. low density polyethylene · CPC title

• B29C48/0012

  combined with shaping by internal pressure generated in the material, e.g. foaming · CPC title

• B29C48/307

  specially adapted for bringing together components, e.g. melts within the die · CPC title

• B29K2023/0683

  UHMWPE, i.e. ultra high molecular weight polyethylene · CPC title