Detail Test Guide of Polyolefin Separator for Lithium-ion Battery, Battery separator testing machine

Information on the most widely used ASTM standards within the materials testing industry

Descriptions of the most prominent lSO standards within the materials testing industry

Standards including EN, DIN, JlS, and more

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Material strength is a course that most engineering fields are required to study in university education. This interesting course is very practical and makes use of testing equipment in the materials laboratory.

Mechanical testing of industrial products and components is essential to ensure their load-bearing, fatigue resistance, and impact resistance, directly preventing production accidents and ensuring stable operation of equipment. UnitedTest can cover a full range of tests including tensile, hardness, and fatigue, complying with national and international standards, and provides customized industrial mechanical testing solutions.

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Mechanical testing in the food and beverage industry involves the compressive and tensile performance of packaging and the safety of food texture, directly ensuring storage, transportation safety, and the eating experience. UnitedTest can cover all-dimensional mechanical testing for packaging and food texture, comply with national and international standards, and provide customized testing solutions.

Mechanical testing in the packaging industry determines the packaging's resistance to compression, impact, and tension, directly ensuring the safety of contents during storage and transportation. UnitedTest can cover comprehensive mechanical testing for packaging, complying with ISO, ASTM Standards, and provides customized testing solutions for compression, drop, tear, and more.

Mechanical testing in the transportation industry concerns the load-bearing and fatigue resistance performance of core components such as vehicles, tracks, and containers, directly ensuring transport safety and equipment durability. UnitedTest can cover mechanical testing for all types of transportation materials, complying with national and international standards, and provides customized testing solutions including tensile, fatigue, and impact tests.

Metallurgical testing examines the properties of metallic materials to determine if a particular metal is appropriate for its intended use.

Testing of polymer materials covers mechanical, thermal, and chemical properties, verifying strength, heat resistance, composition, and ensuring product quality and compliance.

UnitedTest offer world-class testing solution in testing for polymeric materials, including elastomers, thermoplastics, composites, coatings, and structural adhesives in a variety of industries.

Testing of rubber and elastomers is used to assess the various properties and performance of materials under different conditions. This is crucial for ensuring the safety, functionality, and quality of rubber and elastomer products used in industries such as automotive, construction, consumer goods, and aerospace.

Conduct adhesive testing using various testing methods to determine their performance and characteristics in applications across multiple industries such as aerospace, automotive, construction, packaging, industrial, medical, and energy, thereby supporting application development and quality assurance.

UnitedTest supply machine and testing solution for tension, compression, fracture toughness, direct shear, triaxial and ultrasonic velocity are common concrete and rock testing applications.

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Mechanical testing in the textile fabric industry determines core properties such as fabric tensile strength, tear resistance, and wear resistance, directly affecting product durability and safety. UnitedTest can cover comprehensive mechanical tests for textiles, complying with national standards / ISO standards, and provides customized testing solutions including tensile, tear, and puncture tests.

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Mechanical testing in the glass-ceramics industry determines core properties such as flexural strength, hardness, and fracture toughness, directly helping to avoid brittleness and failure risks. UnitedTest can cover comprehensive testing for flexural strength, hardness, and fracture toughness, compatible with national and ISO/ASTM standards, and provides customized testing solutions.

Tensile test evaluates material resistance to stretching, measuring strength/elongation critical for quality control. UnitedTest offers universal tensile testers (10-600KN) compliant with ASTM/ISO standards, providing tailored solutions for metals, polymers, medical & industrial materials.

Compression test assesses material resistance to compressive loads, measuring strength/deformation critical for quality validation. UnitedTest offers compression testing machines compliant with ASTM/ISO standards, providing tailored solutions for concrete, plastics, metals and industrial components.

Flexural & Bend tests evaluate material resistance to bending forces, measuring strength, stiffness and ductility for quality assurance. UnitedTest provides flexural testing machines (3-point/4-point bend) compliant with ASTM/ISO standards, offering tailored solutions for composites, plastics, metals and construction materials.

Torsion Test evaluates material resistance to rotational forces, measuring torsional strength/ductility critical for fasteners, insulators, shafts. UnitedTest offers torsion testers compliant with ASTM A938/ISO 16047, providing tailored solutions for automotive, aerospace, fastener industries.

Fatigue Test assesses material durability under cyclic loading, critical for predicting service life of industrial components. UnitedTest offers fatigue testing systems (axial/bending/torsion) compliant with ASTM E466/ISO 12106, providing tailored solutions for automotive, aerospace and manufacturing sectors.

Peel Test measures material adhesion strength by evaluating resistance to peeling forces, critical for adhesives, films, packaging. UnitedTest offers peel testers compliant with ASTM D903/ISO 8510, covering 90°/180° peel tests, and tailored solutions for packaging, automotive, textile industries.

Impact Test evaluates material resistance to sudden shock loads, critical for assessing toughness and fracture risk. UnitedTest offers impact testers (Charpy/Izod/fall weight) compliant with ASTM E23/ISO 148, providing tailored solutions for metals, plastics, glass and industrial components.

Tear & Shear Test evaluates material resistance to tearing and shearing forces, measuring critical strength parameters for quality control. Tear tests (Elmendorf/trouser/trapezoidal) assess resistance to crack propagation in films/fabrics, while shear tests measure resistance to parallel forces in joints/bolts. UnitedTest provides universal testing machines (10KN-600KN) with specialized fixtures for both tests, compliant with ASTM D624/D3164 and ISO standards, serving automotive, packaging and construction industries.

Hardness test measures material's resistance to permanent indentation, critical for quality control. UnitedTest offers universal hardness testers (Rockwell/Brinell/Vickers) compliant with ASTM/ISO standards, plus tailored hardness testing solutions for diverse industrial needs.

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Friction and wear tests assess material resistance to friction, abrasion and wear, critical for industrial material performance validation. UnitedTest offers tribometers compliant with ASTM G99/ISO standards, covering pin-on-disk, four-ball tests, and tailored friction & wear testing solutions for diverse industries.

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Lithium-Ion Battery Separator Performance Testing Machine | UnitedTest

UnitedTest manufactures professional lithium-ion battery separator testing machines to comprehensively verify the physical, thermal, electrical, and permeability performance of battery separator films for new energy battery production quality control and material R&D.

Lithium-ion battery separators are critical core components inside lithium batteries. Since lithium battery electrolytes adopt organic solvent systems, battery separators require excellent organic solvent resistance. Most industrial separators are produced from high-strength polyolefin thin films — including polyethylene (PE) and polypropylene (PP) — via dry-process or wet-process manufacturing technologies.

The primary function of lithium battery separators is to isolate positive and negative electrodes to prevent internal short circuits, while enabling free lithium ion transmission through uniform microporous structures. Key material properties including thickness uniformity, mechanical strength, air permeability, and thermal stability directly determine the safety, stability, and service life of lithium-ion batteries.

For power battery applications, high-safety composite separator films with thermal dimensional stability and automatic shutdown protection are widely adopted. Additionally, ceramic-coated and organic-coated battery separators feature upgraded puncture resistance and high-temperature heat resistance for enhanced battery safety performance.

To fully qualify battery separator quality, UnitedTest provides all-in-one testing solutions covering all essential performance tests: tensile strength and elongation test, thermal shrinkage test, puncture strength test, air permeability test, porosity test, electric strength test, and ionic conductivity test.

Scope & Application Industry Field

Separators mainly produced from polyolefin resin (dry uniaxial stretching, dry biaxial stretching, wet biaxial stretching three categories).

Consumer lithium batteries (mobile phones, laptops, wearables)

Power lithium batteries (new energy vehicles, two-wheel electric vehicles)

Energy storage lithium batteries (grid energy storage, household energy storage)

Separator raw material factories, battery cell manufacturing plants, third-party testing laboratories, quality supervision institutions.

General List of Main test for the Polyolefin Separator for Lithium-ion Battery

Physical Mechanical Properties
Tensile strength & elongation test	Film tensile (250 mm/min, 15‑mm Type‑2 fixture, 0.01 N res); Follow ISO 527-3.
Thermal shrink	Forced‑air oven, filter‑paper jig, 90/120 °C programs
Puncture Strength	Puncture test fixture with univeral testing machine, Φ1 mm / R0.5 needle, 10‑mm fixture
Air Permeability (Gurley‑method)	Time for 100 mL air to pass through 6.45 cm² area under 1.21 kPa at ambient temp/RH.
Porosity	Balance + thickness + areal calc (software side)
Electrical Properties
Electric strength	50‑point electrode BDV tester (film version)
Ionic conductivity	Jig + EIS integration (layers 1–4, auto regression)

Detail Test Guide of Polyolefin Separator for Lithium-ion Battery

A lithium battery separator is an ultra-thin plastic film with uniform micropores (usually only a few microns to tens of microns thick). It basically does three main things:

Insulation and separation: Like a 'firewall,' it keeps the positive and negative electrodes apart, preventing short circuits from direct contact.

Ion conduction: The micropores act like 'channels,' allowing lithium ions to move smoothly between the electrodes during charging and discharging.

Safety protection: At high temperatures (usually 120-160°C), the micropores automatically close, cutting off ion transport and preventing thermal runaway, making it a true 'lifesaver' for lithium batteries.

Details introduction of test for Polyolefin Separator for Lithium-ion Battery

1, Tensile Strength & Elongation at Break
Test Equipment	UnitedTest Universal tensile testing machine, adjustable test speed 250 mm/min, fixture initial distance 100 mm. Long travel extensometer.
Test Specimen info	Type 2 specimen, width (15±0.1) mm; mark MD (longitudinal) & TD (transverse) separately, prepare multiple MD/TD strips.
Test Procedure	Condition samples 4h; clamp specimen with 100 mm gauge length; Set test speed (250±10) mm/min, pull until rupture; Record maximum tensile force and elongation at break, convert to tensile strength (MPa).
Test requirement	Dry uniaxial: MD ≥ 110 MPa, TD ≥ 10 MPa; elongation MD ≥ 80 %, TD ≥ 10 % Dry biaxial: MD/TD ≥ 100 / 25 MPa; elong MD ≥ 20 %, TD ≥ 80 % Wet biaxial: MD/TD ≥ 100 / 60 MPa; both ≥ 50 %
2, Thermal Shrinkage Test
Test Equipment	Forced air convection oven (temperature accuracy ±1°C); Stainless steel flat plate, quantitative filter paper.
Test Specimen info	3 square specimens of 100 mm × 100 mm; if separator width <100 mm, sample size =100 mm × film width. Mark MD & TD on each sample.
Test Procedure	Measure original MD & TD length of conditioned samples; Preheat oven to target temperature (90±1°C or 120±1°C); lay sample between two filter papers on stainless plate inside oven; Keep constant temperature for specified time (2h±12min / 1h±6min); Cool sample to room temperature, re-measure length, calculate shrinkage rate average of 3 samples.
Test requirement	90 °C × 2 h → MD ≤ 4 %, TD varies (dry uniaxial ≤ 0.5 %, dry biaxial ≤ 2 %, wet ≤ 2.5 %) 120 °C × 1 h → dry uniaxial MD ≤ 6 / TD ≤ 1; dry & wet biaxial ≤ 5 / ≤ 13
3, Puncture Strength Test
Test Equipment	Universal Tester with load cell resolution 0.01 N Puncture fixture with needle: Φ1.0 mm, spherical tip R=0.5 mm Sample fixture with inner diameter 10 mm.
Test Procedure	Clamp flat separator tightly in fixture; Set test speed (100±10) mm/min, lower needle to pierce sample; record peak puncture force \(F_0\); Measure thickness at 4 positions around the puncture hole to get average thickness; Calculate normalized puncture strength per micron thickness.
Test requirement	Dry separator: ≥0.133 N/μm Wet separator: ≥0.204 N/μm
4, Air Permeability Test
Test Equipment	Separator air permeability tester, fixed test area 6.45 cm², constant 1.21 kPa differential pressure.
Test Specimen	3 specimens, longitudinal interval 150 mm; size 100×100 mm if film width ≥100 mm; else 100 mm × film width.
Test Procedure	Mount conditioned sample on test head, run test, record air passing time, take average of 3 specimens.
Test requirement	Index unit: s/100mL; acceptance value subject to customer detailed specification. Definition: Time for 100 mL air passing through 6.45 cm² film under 1.21 kPa pressure.
5, Porosity Test
Test Specimen	3 specimens same size as air permeability test (100×100 mm or 100 mm × film width).
Test Equipment	Analytical balance (resolution 0.0001 g); Thickness gauge, length/width caliper
Test Procedure	Measure sample length, width, multi-point thickness to get average d; weigh sample mass m; Input PP/PE raw material true density p₀ into formula to compute porosity percentage.
6, Electrical Strength (Dielectric Breakdown Strength)
Test Equipment	50-point electrical strength breakdown tester for insulating film.
Test Specimen info	Large flat separator sheet covering full 50-point electrode area.
Test Procedure	Place conditioned separator on electrode platform, execute 50-point breakdown voltage test, calculate average & minimum V/μm value.
Test requirement	Minimum electrical strength ≥30 V/μm Average electrical strength ≥50 V/μm Test standard basis: IEC 60674-2, 50-point electrode method
7, Ionic Conductivity Test
Test Equipment	AC impedance EIS test system Sealed test mould, electrolyte: 1.0 mol/L LiPF6 (EC:EMC:DMC=1:1:1 volume ratio)
Test Specimen info	4 identical separator sheets matching resistance mould size.
Test Procedure	Immerse 4 separator layers in electrolyte, seal & soak 2 hours fully saturated; Test impedance of 1/2/3/4 layers separately; plot impedance-layer fitting curve; If linear fitting coefficient >0.99, extract single-layer resistance R to compute ionic conductivity; re-test if fitting <0.99.

Why the test/inspection is Critical for Polyolefin Separator Materials?

Lithium battery separator is the core safety component: it separates anode and cathode, blocks electronic short-circuit, and allows lithium ion passage. Non-standard tested separators will cause battery swelling, short circuit, thermal runaway, fire or explosion.

Unified Quality Benchmark: Eliminates inconsistent testing standards between separator suppliers and battery manufacturers, standardizes acceptance indicators.

Safety Risk Control: Strictly limits thermal shrinkage, puncture resistance, electrical strength to prevent internal short-circuit caused by high temperature or dendrite piercing.

Performance Consistency Guarantee: Standardizes thickness, width, porosity, air permeability to stabilize battery rate discharge, cycle life and energy density.

Regulatory & Inspection Basis: National quality supervision, factory outgoing inspection, type testing all rely on this standard for compliance judgment.

Industry Upgrading Guide: Defines technical thresholds for dry/wet separators, guides R&D of high-safety coated separators.

Keywords: UnitedTest battery separator testing machine, lithium ion battery separator performance tester, polyolefin film battery test equipment, battery safety performance testing machine, dry wet process PE PP battery separator tensile elongation test, ceramic coated battery separator puncture resistance tester, lithium battery separator thermal shrinkage testing equipment, battery film air permeability and porosity analyzer, ionic conductivity and electric strength test for battery separators, power battery composite film thermal stability tester

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