US20070238017A1 - Multilayer separator exhibiting improved strength and stability - Google Patents

Multilayer separator exhibiting improved strength and stability Download PDF

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Publication number
US20070238017A1
US20070238017A1 US11/400,465 US40046506A US2007238017A1 US 20070238017 A1 US20070238017 A1 US 20070238017A1 US 40046506 A US40046506 A US 40046506A US 2007238017 A1 US2007238017 A1 US 2007238017A1
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United States
Prior art keywords
layer
battery separator
microporous
microporous battery
tri
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Abandoned
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US11/400,465
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English (en)
Inventor
Ronald Call
Lie Shi
Zhengming Zhang
Shizuo Ogura
Xiangyun Wei
Premanand Ramadass
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Celgard LLC
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Celgard LLC
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Priority to US11/400,465 priority Critical patent/US20070238017A1/en
Assigned to CELGARD LLC reassignment CELGARD LLC ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: CALL, RONALD W., OGURA, SHIZUO, SHI, LIE, WEI, XIANGYUN, ZHANG, ZHENGMING, RAMADASS, PREMANAND
Priority to TW096109894A priority patent/TWI433379B/zh
Priority to JP2007099015A priority patent/JP5065737B2/ja
Priority to KR1020070033623A priority patent/KR100863100B1/ko
Priority to CNB2007100903592A priority patent/CN100544074C/zh
Publication of US20070238017A1 publication Critical patent/US20070238017A1/en
Priority to US12/755,471 priority patent/US8486556B2/en
Priority to JP2012176903A priority patent/JP5694255B2/ja
Abandoned legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
    • B29C55/023—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets using multilayered plates or sheets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
    • B32B37/14—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers
    • B32B37/15—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers with at least one layer being manufactured and immediately laminated before reaching its stable state, e.g. in which a layer is extruded and laminated while in semi-molten state
    • B32B37/153—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers with at least one layer being manufactured and immediately laminated before reaching its stable state, e.g. in which a layer is extruded and laminated while in semi-molten state at least one layer is extruded and immediately laminated while in semi-molten state
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B38/00—Ancillary operations in connection with laminating processes
    • B32B38/0032—Ancillary operations in connection with laminating processes increasing porosity
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/417—Polyolefins
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H01M50/457—Separators, membranes or diaphragms characterised by the material having a layered structure comprising three or more layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • 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
    • H01M50/491—Porosity
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
    • B29K2023/04—Polymers of ethylene
    • B29K2023/06—PE, i.e. polyethylene
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
    • B29K2023/10—Polymers of propylene
    • B29K2023/12—PP, i.e. polypropylene
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B38/00—Ancillary operations in connection with laminating processes
    • B32B38/0012—Mechanical treatment, e.g. roughening, deforming, stretching
    • B32B2038/0028—Stretching, elongating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B38/00—Ancillary operations in connection with laminating processes
    • B32B38/0036—Heat treatment
    • B32B2038/0048—Annealing, relaxing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2305/00—Condition, form or state of the layers or laminate
    • B32B2305/02—Cellular or porous
    • B32B2305/026—Porous
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2457/00—Electrical equipment
    • B32B2457/10—Batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention is a battery separator and a method of making this separator.
  • the invented separator exhibits an increase in mixed penetration tests and in decreased shrinkage when compared to other separators made by either a dry stretch process or solvent extraction process.
  • the separators of the invention also have a Gurley of 13 to 25 seconds even with a porosity of less than or equal to 37%.
  • microporous multi-layered membranes as battery separators. See, for example, U.S. Pat. Nos. 5,480,745; 5,691,047; 5,667,911; 5,691,077; and 5,952,120.
  • U.S. Pat. No. 5,480,745 discloses forming a multi-layered film by co-extruding the multi-layered precursor or by heat-welding, at 152° C., pre-formed precursor layers.
  • the multi-layered precursor, formed by either technique is then made microporous by annealing and stretching.
  • This membrane which is made by a dry stretch process, has a preferable amount of net stretch is from 100% to 300%.
  • U.S. Pat. No. 5,691,047 discloses forming the multi-layered film by co-extruding the multi-layered precursor or by uniting, under heat (120-140° C.) and pressure (1-3 kg/cm 2 ), three or more precursor layers.
  • one 34 ⁇ m separator has a peel strength of 1 g/mm and the other, about 0.5 g/mm.
  • the multi-layered precursor, formed by either technique is then made microporous by annealing and stretching. The porosity of these separators is greater than the present invention while showing a relatively high Gurley.
  • U.S. Pat. No. 5,667,911 discloses forming the multi-layered film by uniting (by heat and pressure or by adhesives) cross-plied microporous films to form a multi-layered microporous film.
  • the microporous films are laminated together using heat (110° C. -140° C.) and pressure (300-450 psi) and at line speeds of 15-50 ft/min (4.6-15.2 m/min).
  • This reference teaches lower Gurley values, which is a good indication that the porosity of these films is high.
  • U.S. Pat. No. 5,691,077 discloses forming the multi-layered film by uniting, by heat and pressure (calendering), or by adhesives, or by pattern welding, microporous films to form a multi-layered microporous film. Calendering is performed at 125° C. to 130° C. for a residence time of 2 to 10 minutes. Four (4) stacked multi-layered microporous precursors are calendering between a single nip roll. The porosity of these separators is greater than the present invention while showing a relatively high Gurley.
  • U.S. Pat. No. 5,952,120 discloses forming the multi-layered film by extruding nonporous precursors, bonding together nonporous precursors, annealing the bonded, nonporous precursors, and stretching the bonded, nonporous precursors to form a multi-layered microporous film. At least four (4) tri-layer precursors are simultaneously passed through the steps of bonding, annealing, and stretching. Bonding was performed between nip rollers at 128° C.
  • the invention is a multi-layer microporous battery separator, having a high molecular weight polypropylene layer, indicated by a melt flow index of ⁇ 1.2 measured at the layer, a polyethylene layer, and a high molecular weight polypropylene layer, which has a melt flow index of ⁇ 1.2 measured at layer.
  • This resulting microporous battery separator is formed by a dry stretch process.
  • the microporous battery separator has a porosity of ⁇ 37% while maintaining a gurley from 13-25 seconds for a separator with a thickness of ⁇ 25 microns.
  • FIG. 1 is a side view of a multilayer separator in a mixed penetration test.
  • FIG. 2 is side view showing the electrodes and the separator after pressure is applied.
  • FIG. 3 is a graph showing a slope of the ionic resistance of a separator.
  • FIG. 4 is a schematic view of a four probe AC impedence technique for measuring the ionic resistance of separator membranes.
  • FIG. 5 is a graph of the percentage increase in mixed penetration strength of the multilayer membranes made by the current process of multilayer dry stretch membranes of the same thickness.
  • a battery separator refers to a microporous film or membrane for use in electrochemical cells or capacitors.
  • Electrochemical cells include primary (non-rechargeable) and secondary (rechargeable) batteries, such as batteries based on lithium chemistry.
  • These films are commonly made of polyolefins, for example, polyethylene, polypropylene, polybutylene, polymethylpentene, mixtures thereof and copolymers thereof.
  • Polypropylene (including isotactic and atactic) and polyethylene (including LDPE, LLDPE, HDPE, and UHM WPE) and blends thereof and their copolymers are the preferred polyolefins that are used to make commercially available films for these applications.
  • These films may be made by the CELGARD® process (also known as the dry process, i.e., extrude-anneal-stretch) or by a solvent extraction process (also known as the wet process or phase inversion process or TIPS, thermally induced phase separation, process) or by a particle stretch process.
  • Some of these films, those made by the dry process, are often multi-layered films. Multi-layered films are preferred because they have shutdown capability (i.e., can stop the flow of ions in the event of short circuiting).
  • a common multi-layered film is the tri-layered film.
  • a popular tri-layered film has a polypropylene (PP)/polyethylene (PE)/polypropylene (PP) structure, another structure is PE/PP/PE.
  • the present invention is to a multi-layer microporous battery separator which has three layers.
  • the first layer is a high molecular weight polypropylene layer having a melt flow index of less than or equal to ( ⁇ ) 1.2 measured at layer, a second polyethylene layer, and a third high molecular weight polypropylene layer, which has a melt flow index of ⁇ 1.2 measured at the layer.
  • This microporous battery separator is formed by a dry stretch process.
  • the process of the invention produces the microporous battery separator which has a porosity of less than or equal to ⁇ 37% while maintaining a Gurley from 13-25 seconds and a thickness of less than or equal to ⁇ 25 microns.
  • This multi-layer microporous battery separator exhibits an increase of 5% or more in mixed penetration strength compared to a tri-layer dry-stretched microporous battery separator of the same thickness.
  • the net shrinkage of this microporous battery separator is less than 5% after an exposure of 6 hours at 105° C.
  • the ionic resistance of this microporous battery separator is less than 2.5 ohms-cm 2 .
  • the polyethylene layer of this separator is a high density polyethylene.
  • the multi-layer microporous battery separator comprises a tri-layer dry-stretched microporous battery separator, which has an outer polyolefin layer, an inner polyolefin layer and an outer polyolefin layer.
  • the overall thickness of the separator is ⁇ 25 microns.
  • the outer polyolefin layers are a high molecular weight polypropylene.
  • the inner polyolefin layer is a polyethylene.
  • This multi-layer microporous battery separator has a porosity of ⁇ 37% while maintaining a gurley from 13-25 seconds. Surprisingly, the net shrinkage of this microporous battery separator is less than 5% measured for 6 hours at 105° C. This multi-layer microporous battery separator has an ionic resistance of less than 2.5 ohm-cm 2 .
  • Another embodiment of the invention is a multi-layer microporous battery separator which comprises a tri-layer dry-stretched microporous battery separator.
  • This separator has an outer polyolefin layer an inner polyolefin layer and an outer polyolefin layer.
  • the outer polyolefin layers are a high molecular weight polypropylene.
  • the inner polyolefin layer is a polyethylene.
  • This tri-layer dry-stretched microporous battery separator has a thickness of ⁇ 25 microns, a porosity of 37% or lower and a Gurley from 13-25 seconds.
  • This separator exhibits a 5% increase in mixed penetration strength compared to a tri-layer dry-stretched microporous battery separator of the same thickness.
  • This multi-layer microporous battery separator surprisingly exhibits a net shrinkage of less than 5% measured for 6 hours at 105° C.
  • the multi-layer microporous battery separator also has an ionic resistance of the microporous battery separator is less than 2.5 ohm-cm 2 .
  • the invented separator can be prepared by the following process of the preparation of a multi-layer microporous battery separator.
  • a polypropylene having a MFI ⁇ 1.0 measured at pellet before processing and a polyethylene is provided.
  • the polypropylene which is a high molecular weight polypropylene, is extruded to form a precursor polypropylene film.
  • a polyethylene is provided and is extruded to form a precursor polyethylene film.
  • the precursor polypropylene films are then laminated to each side of the precursor polyethylene film to form a non-porous tri-layer precursor. This non-porous tri-layer precursor is then annealed.
  • the non-porous tri-layer precursor is then stretched to form a stretched microporous tri-layer film.
  • the stretched microporous tri-layer film is then allowed to relaxed to form a microporous tri-layer film.
  • the net stretch in this process is less than 90%. Net stretch is determined by the percentage of stretch given to the film minus the amount relax. Stretch may be done either hot or cold or as mixture of hot and cold. The relaxation may also be performed either hot or cold or as a mixture of both hot and cold.
  • a battery separator made of a microporous polyolefin which has an overall thickness of ⁇ 25 microns, where the net shrinkage of the separator is less than 5% measured for 6 hours at 105° C.
  • This battery separator has a porosity of 37% or lower.
  • this battery separator has a Gurley from 13-25 seconds. Traditionally in order to obtain a Gurley level in the 13-25 second range a separator had to have a porosity of more than 37% and in most cases the porosity was at least 40% or more. It has been seen that even small changes in porosity tend to have a big impact of the Gurley for a separator.
  • a battery separator made of a microporous polyolefin having an overall thickness of ⁇ 25 microns, where the net shrinkage of the separator is less than 5% measured for 6 hours at 105° C., where the separator has a porosity of ⁇ 37% while maintaining a gurley from 13-25 seconds is surprising for a separator made by a wet process as well as a separator made by a dry process.
  • a multi-layer battery separator is made of a microporous polyolefin having an outer layer of a high molecular weight polypropylene layer, which has a melt flow index of ⁇ 1.2 measured after processing at the outer layer.
  • the measurement at the layer is important because many polypropylenes that may be referred to as high density will see a significant fall off in the melt flow performance after processing. In the past when melt flow index was used it always referred to the melt flow prior to processing.
  • Gurley is measured by the ASTM D-726(B) method.
  • Gurley is the resistance to air flow measured by the Gurley Densometer (e.g. Model 4120).
  • Gurley values set forth herein are expressed as the time in seconds required to pass 10 cc of air through one square inch of product under a pressure 12.2 inches of water.
  • the tensile strength along MD and TD is measured with the ASTM D-638 method.
  • the tear resistance is measured by ASTM D-1004.
  • the thickness of the battery separator is measured by the T411 om-83 method developed under the auspices of the Technical Association of the Pulp and Paper Industry. Thickness is determined using a precision micrometer with a 1 ⁇ 2 inch diameter, circular shoe contacting the sample at seven (7) psi. Ten (10) individual micrometer readings taken across the width of the sample are averaged.
  • the porosity of a microporous film is measured by the method of ASTM D-2873.
  • Puncture strength is measured as follows: ten measurements are made across the width of the stretched product and averaged. A Mitech Stevens LFRA Texture Analyzer is used. The needle is 1.65 mm in diameter with 0.5 mm radius. The rate of descent is 2 mm/sec and the amount of deflection is 6 mm. The film is held tight in the clamping device with a central hole of 11.3 mm. The displacement (in mm) of the film that was pierced by the needle was recorded against the resistance force (in gram force) developed by the tested film. The maximum resistance force is the puncture strength.
  • Mixed penetration is the force required to create a short through a separator due to mixed penetration.
  • a base of a metal plate 10 FIG. 1
  • a sheet of cathode material 15 on top of this plate is placed a sheet of cathode material 15
  • a multilayer separator 20 on top of the multilayer separator 20 is placed a sheet of anode material 25 .
  • a ball tip of 3 mm, 30 is then provided attached to a force gauge 35 .
  • the ball tip 30 is connected to the metal plate 10 by a resistance meter 40 .
  • Pressure 45 FIG. 2 , is applied to the ball tip 30 , which is recorded on the force gauge 35 , FIG. 1 .
  • Once force is applied there builds up an anode mix 50 , FIG. 2 and a cathode mix 55 on either side of the separator 20 .
  • the resistance falls dramatically it indicates a short through the separator due to mixed penetration.
  • Melt Index is measured according to ASTM DS 1238; PE: 190° C./2.16 Kg; PP: 230° C./2.16 Kg. It is measured as g/10 minutes.
  • the shrinkage is measured at 105 ° C. for 6 hours. Both width and length of a separator membrane are measured before and after the said heat treatment.
  • the measurement ionic resistance of separator soaked with a certain electrolyte is very important to the art of battery manufacture, because of the influence the separator has on electrical performance. Ionic resistance is a more comprehensive measure of permeability than the Gurley number, in that the measurement is carried out in the actual electrolyte solution for real battery application.
  • the ionic resistance of the porous membrane is essentially the ionic resistance of the electrolyte that is embedded in the pores of the separator.
  • a microporous separator, immersed in an electrolyte has an electrical resistance about 6-7 times that of a comparable volume of electrolyte, which it displaces. It is a function of the membrane's porosity, tortuosity, the resistance of the electrolyte, the thickness of the membrane, and the extent to which the electrolyte wets the pores of the membrane.
  • the separator resistance is characterized by cutting small pieces of separators from the finished material and then placing them between two blocking electrodes.
  • the separators are completely saturated with the battery electrolyte with 1.0M LiPF 6 salt in EC/EMC solvent of 3:7 ratio by volume.
  • the resistance, R ( ⁇ ) of the separator is measured by 4-probe AC impedance technique. In order to reduce the measurement error on the electrode/separator interface, multiple measurements are needed by adding more separator layers.
  • FIG. 4 shows the schematic 60 of the cell used to measure the resistance.
  • the lead coming out of the top 65 and bottom 70 probes of the cell has two wires each 75 , 80 one for sensing current and other for voltage.
  • Electrolyte used for all resistance measurement is 1.0 M LiPF6 salt in EC:EMC solvent of a 3:7 ratio by volume.
  • the separator should completely cover the bottom electrode and the separator should be completely wet with electrolyte.
  • the impedance value is measured with an impedance meter 95 from Potentiostat.
  • Sample A & B are for a competitive trilayer separator made by a dry stretch process.
  • Sample A is a 20 micron separator sample B is for a 25 micron separator.
  • Examples C300 and C500 are for the invented separator made by the invented process.
  • C300 is a 20 micron separator and C500 is for a 25 micron separator.
  • IR stands for ionic resistance
  • P.S. puncture strength
  • MP mixed penetration
  • TD traverse direction compared to the machine direction.
  • the invented material is compared against a trilayer separator made by the Celgard® process which does not use a high molecular weight polypropylene and is not made in accordance with the process of the invention.
  • FIG. 5 the improvement in mixed penetration strength can be seen.
  • table A where the a standard 20 micron separator shows a 10% reduction in mixed penetration strength compared to a standard 25 micron trilayer separator.
  • the 20 micron invented separator made by the invented process shows only a 2% reduction in mixed penetration strength.
  • the standard 25 micron separator shows no change in mixed penetration strength, where the 25 micron separator made by the invent process shows an increase in mixed penetration strength of 5%.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Cell Separators (AREA)
US11/400,465 2006-04-07 2006-04-07 Multilayer separator exhibiting improved strength and stability Abandoned US20070238017A1 (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
US11/400,465 US20070238017A1 (en) 2006-04-07 2006-04-07 Multilayer separator exhibiting improved strength and stability
TW096109894A TWI433379B (zh) 2006-04-07 2007-03-22 具有改良強度及穩定性之多層分離器
JP2007099015A JP5065737B2 (ja) 2006-04-07 2007-04-05 改良された強度及び安定性を示す多層分離膜
KR1020070033623A KR100863100B1 (ko) 2006-04-07 2007-04-05 향상된 강도 및 안정성을 갖는 복층 분리막
CNB2007100903592A CN100544074C (zh) 2006-04-07 2007-04-06 表现出改善强度和稳定性的多层隔板
US12/755,471 US8486556B2 (en) 2006-04-07 2010-04-07 Multilayer separator exhibiting improved strength and stability
JP2012176903A JP5694255B2 (ja) 2006-04-07 2012-08-09 改良された強度及び安定性を示す多層分離膜

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US11/400,465 US20070238017A1 (en) 2006-04-07 2006-04-07 Multilayer separator exhibiting improved strength and stability

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US12/755,471 Continuation US8486556B2 (en) 2006-04-07 2010-04-07 Multilayer separator exhibiting improved strength and stability

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US20070238017A1 true US20070238017A1 (en) 2007-10-11

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US20180261817A1 (en) * 2006-11-17 2018-09-13 Celgard, Llc Co-extruded, multi-layered battery separator
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US20100009249A1 (en) * 2006-10-13 2010-01-14 Toyo Tanso Co., Ltd Separator for nonaqueous electrolyte secondary battery and multilayer separator for nonaqueous electrolyte secondary battery
US20180261817A1 (en) * 2006-11-17 2018-09-13 Celgard, Llc Co-extruded, multi-layered battery separator
US10818899B2 (en) * 2006-11-17 2020-10-27 Celgard, Llc Co-extruded, multi-layered battery separator
US20110236745A1 (en) * 2008-11-26 2011-09-29 Toray Tonen Specialty Separator Godo Kaisha Microporous membrane, methods for making such film, and the use of such film as battery separator film
US8815436B2 (en) 2008-11-26 2014-08-26 Toray Battery Separator Film Co., Ltd. Microporous membrane, methods for making such film, and the use of such film as battery separator film
US8901240B2 (en) 2009-01-07 2014-12-02 Mitsui Chemicals Inc. Polypropylene resin composition for use in formation of microporous membrane
US8916644B2 (en) 2009-01-07 2014-12-23 Toray Battery Separator Film Co., Ltd Polypropylene resin composition for use in formation of microporous membrane
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US20100255376A1 (en) * 2009-03-19 2010-10-07 Carbon Micro Battery Corporation Gas phase deposition of battery separators
WO2012018675A1 (en) * 2010-08-02 2012-02-09 Celgard, Llc High melt temperature microporous lithium-ion rechargeable battery separators and methods of preparation and use
US10826108B2 (en) 2010-08-02 2020-11-03 Celgard, Llc High melt temperature microporous lithium-ion rechargeable battery separators and methods of preparation and use
US9490462B2 (en) * 2011-12-01 2016-11-08 Gs Yuasa International Ltd. Separator and nonaqueous electrolytic secondary battery including the same
US20130143089A1 (en) * 2011-12-01 2013-06-06 Gs Yuasa International Ltd. Separator and nonaqueous electrolytic secondary battery including the same
WO2014152130A1 (en) * 2013-03-15 2014-09-25 Celgard, Llc Multilayer hybrid battery separators for lithium ion secondary batteries and methods of making same
US9455432B2 (en) 2013-03-15 2016-09-27 Celgard, Llc Multilayer hybrid battery separators for lithium ion secondary batteries and methods of making same
US10601012B1 (en) 2013-03-15 2020-03-24 Celgard, Llc Multilayer hybrid battery separators for lithium ion secondary batteries and methods of making same
US10586964B2 (en) 2013-08-12 2020-03-10 Solvay Sa Solid composite fluoropolymer separator
WO2015022229A1 (en) 2013-08-12 2015-02-19 Solvay Sa Solid composite fluoropolymer separator
WO2016085948A1 (en) * 2014-11-26 2016-06-02 Celgard, Llc Improved microporous membrane separators for lithium ion rechargeable batteries and related methods
CN112397846A (zh) * 2014-11-26 2021-02-23 赛尔格有限责任公司 用于锂离子二次电池的改进的多层微孔膜隔板及相关方法
US11728546B2 (en) 2014-11-26 2023-08-15 Celgard, Llc Microporous membrane separators for lithium ion rechargeable batteries and related methods
WO2017049065A1 (en) 2015-09-18 2017-03-23 Celgard, Llc Improved membranes, calendered microporous membranes, battery separators and related methods
EP4123816A1 (en) * 2015-09-18 2023-01-25 Celgard, LLC Membranes, calendered microporous membranes, battery separators, and related methods
US11569549B2 (en) 2015-09-18 2023-01-31 Celgard, Llc Membranes, calendered microporous membranes, battery separators, and related methods
EP3350854A4 (en) * 2015-09-18 2019-06-12 Celgard, LLC IMPROVED MEMBRANES, CALANIZED MICROPOROUS MEMBRANES, BATTERY-ELEMENTS AND RELATED METHODS
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US11784344B2 (en) 2015-11-11 2023-10-10 Celgard, Llc Microlayer membranes, improved battery separators, and methods of manufacture and use
EP3411916A4 (en) * 2016-01-29 2019-09-11 Celgard LLC IMPROVED SEPARATORS, BATTERY SYSTEMS, VEHICLES AND RELATED METHODS
US20200303704A1 (en) * 2017-11-03 2020-09-24 Celgard, Llc Improved microporous membranes, battery separators, batteries, and devices having the same
US20210080364A1 (en) * 2018-03-28 2021-03-18 Lg Chem, Ltd. Method for evaluating stability of separator

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US20100209758A1 (en) 2010-08-19
JP2013012484A (ja) 2013-01-17
KR100863100B1 (ko) 2008-10-13
KR20070100644A (ko) 2007-10-11
CN100544074C (zh) 2009-09-23
JP2007311332A (ja) 2007-11-29
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JP5065737B2 (ja) 2012-11-07
JP5694255B2 (ja) 2015-04-01

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