Resonate Testing performs UL 2596 battery enclosure material testing for polymer, composite and non-metallic housings used in Aircraft, EV, energy storage programmes.
Resonate provides UL 2596 testing enabling manufacturers to assess enclosure materials, fire performance, flame exposure response and containment evidence for lightweight polymer, composite and non-metallic battery housings.
UL 2596, is a comparative test method to evaluate enclosure materials, particularly non metallic lightweight polymers and composite housings used in battery packs, electric vehicles and energy storage systems.
Material Evaluation: This standard is a development tool, usually used to access the relative performance of a range of materials for battery containment.
Direct Exposure to a standardised thermal runaway event: Representative enclosure material specimens are exposed to flame conditions to assess resistance to ignition, flame spread and burn-through.
Containment performance: Testing helps show whether the enclosure material can help limit flame propagation during a battery thermal event.
Containment, external surface temperature / ignition, Self-extinguishing behaviour: The material response after flame exposure is reviewed to understand whether burning continues or stops within the expected criteria.
Design validation / comparison: Results support material selection, comparison and wider battery safety design considerations.
Environmental Testing
Corrosion and Salt Spray Testing
Humidity Testing
Rain and Water Ingress Testing
Sand and Dust Testing
Ready to plan an UL 2596 testing campaign? Send your requirement, drawings, installation assumptions or certification plan for engineer review and receive guidance on fireproof or fire-resistant classification, setup, instrumentation and evidence requirements.
Although standard UL2596 testing is quite standard. Its worth engaging with Resonate before final coupon manufacture as there are many be considerations on exact coupon size and anti-compression plates around the outside to prevent crushing of sandwich panels and unrealistic edge loading condition that may contribute to failure under the internal pressure. Material type, wall thickness, construction, coatings, joints and intended battery application can all affect details of the test execution
Share your requirements and test goals and let us discuss the options with you, and provide a quote for testing that fills your requirements.
Resonate is the only lab that we are aware of that offers these types of tailored options. The standard UL2596 test uses 25 Panasonic NCR18650B cells of 3350 mAh capacity and Lithium Nickel Cobalt Aluminium Oxide (NCA)chemistry. As most lightweight battery enclosures are for the Aerospace or other weigh sensitive transport sectors, 18650 NCA cells with 3350 are not the most weight efficient power dense option. the customer has already selected a different chemistry and cell format for the application. In such cases Resonate has constructed a bespoke test with the actual cells in a representative configuration and bespoke enclosure. This is because a thermal runaway event has many influencing characteristics:
Chemistry affects: burn rate within the cell, the energy release, amount and types of gases and compounds formed, the speed & likelihood of propagation.
Cell size and format and casing affects: The rate at which the energy is released, release rate within a cell is faster than between cells. The casing of the cell may melt (pouch cells) or metal cases may blow a vent cap causing direct impingement to the casing material or cause mechanical loading due to internal pressure before busting within the pack
Triggering Options: UL2596 use two trigger cells to try to initiate a repeatable thermal runaway. After many standard UN2596 tests Resonate has developed trigger cell strategies to ensure mure consistent and repeatable thermal runway events. which in the end is wat you need for comparative testing.
why not contact Resonate testing and discuss your needs with our battery experts.
| Standard / Guidance | Primary Focus | Typical Relevance |
|---|---|---|
| UL 2596 | Battery enclosure material performance | Performance evaluation for battery enclosure materials. |
| Material construction | Material selection and specimen configuration | Grade, thickness, coatings, joints and representative sample format. |
| Battery application | Application-specific requirements and test conditions | Other applicable regulations due to use case (e.g. aircraft fire wall), R100 pooling fire test (EV)or customer-specific requirements. |
| Customer specifications | Customer-defined and acceptance and inspection requirements | Acceptance criteria, post test inspection methods, (NDT ultrasound) observations and reporting expectations. |
UL 2596 is focused on the performance of battery enclosure materials. It may just be material research by the manufactures or more often it’s early testing in a program developing a battery pack.
We offer a range of battery testing to various industry standards, but we can also offer bespoke testing of module and pack level and instrument and in certain cases build assemble and instrument those packs for customers.
Our substantial battery testing experience shows there are several key areas where designs may encounter issues during tests.
BMS / Controls
BMS logic or calibration faults, modern packs often fail because of controls rather than hardware.
Typical issues: Incorrect SOC calculations, Calibration errors, CAN communication faults
and Incorrect fault logic. Updates to BMS software may invalidate previous testing , requiring re-test.
Wiring / Connectors / Busbars
Normally shown by vibration testing or post test inspection. Typical issues: High contact resistance due to fastener or joint issues, Fretting corrosion from vibration, intermittent connection on pins, Thermal expansion mismatch, Vibration fatigue, Poor weld design
Thermal Management
Very common in high-power EV and aerospace systems, this can lead to Excessive temperature spread across the pack, Thermal derating of power available, Ageing failures and increased propagation vulnerability. Typical initial causes: Poor coolant distribution, Uneven cooling plate contact, Inadequate airflow
Mechanical / Vibration
Vibration testing of packs is a common requirement and UN ECE R100, ISO 16750 vibration and RTCA DO-160 all have vibration testing. Typical issues: Cracked welds, Broken tabs, Chafed HV cables, Loose fasteners, coolant leaks and damage to HV insulation all of which can lead to potentially unsafe conditions.
Testing performed to UL 2596 is intended to evaluate how battery enclosure materials behave during defined flame or heat exposure. Typical objectives include assessing ignition resistance, flame spread, burn-through risk, self-extinguishing behaviour and the material’s contribution to battery enclosure fire containment.
Test planning is normally based on the specific material, enclosure design and programme requirements, including sample thickness, construction, coatings, exposure conditions, observations and reporting expectations. Applicability should be confirmed for the exact material and battery application before testing begins.
Resonate Testing supports UL 2596 battery enclosure material flammability evaluations for manufacturers developing lightweight polymer, composite and non-metallic battery housings.
Testing can help demonstrate whether enclosure materials provide suitable fire containment performance while supporting weight reduction, cost optimisation and wider battery safety objectives.
Early technical review helps confirm whether the submitted samples represent the intended enclosure design. Useful information includes material grade, thickness, construction method, coatings, supplier data, drawings, intended battery application and any wider standards programme.
Outputs may include observations from flame exposure, material behaviour, achieved test conditions, photographs where agreed and a report aligned to the agreed scope. Results can support internal design decisions, customer submissions or a broader compliance pathway.
| Specification | Capability |
|---|---|
| Test Focus | UL 2596 battery enclosure material performance under thermal runaway. |
| Typical Materials | Polymer, composite and non-metallic battery enclosure materials |
| Data collected | Outer skin temperature, internal skin temperature, cell temperatures and reading from multiple pressure sensors tapping in the enclosure, ability to survive the peek pressure from gas release during the event (non rupture), Post test of fuel package and coupon per customer requirements : Loss or burnt material ignition resistance, and self-extinguishing behaviour |
| Sample Review | Material grade, thickness, construction method, coatings and representative geometry |
| Planning Inputs | Material data sheet, enclosure drawings, target application and customer requirements |
| Observation Needs | Flame exposure response, visible damage, continued burning and containment behaviour |
| Reporting Outputs | Achieved conditions, observations, photographs where agreed and scoped test reporting |
| Engineering Support | Pre-test review, specimen planning and evidence alignment for battery safety programmes |
Review: Confirm the material, intended enclosure application, sample format and relevant customer or certification requirements.
Prepare specimens: Agree representative sample dimensions, thickness, conditioning needs and any coating or construction details.
Set up: Confirm orientation, exposure conditions, observations to be recorded and acceptance criteria for the agreed scope.
Expose: Apply the specified flame or heat exposure and monitor ignition, flame spread, burn-through and self-extinguishing behaviour.
Document: Capture achieved conditions, observations, photographs where agreed and any deviations from the planned method.
Report: Provide the agreed evidence package for engineering review, customer submission or wider battery safety validation.
Material data sheet, grade and supplier information
Representative sample geometry, thickness and construction details
Coatings, joints, inserts or layered material information
Target battery enclosure application and installation context
Customer, certification or programme requirements
Number of specimens and any comparison materials
Required observations, photographs or witness needs
Any material handling, safety or conditioning requirements
Acceptance criteria or evidence package expectations
Reporting format and submission requirements
Direct flame exposure is the part of the test where a representative enclosure material specimen is exposed to defined flame or heat conditions. It helps assess whether the material resists ignition, limits flame spread and avoids burn-through under the agreed scope.
Burn-through means flame or heat has penetrated through the specimen. For battery enclosure materials, this is important because the enclosure is expected to help contain a fire event and reduce risk spread of the fire.
Ignition resistance describes how the material behaves when challenged by flame or elevated heat, including whether it ignites under the agreed exposure conditions.
Self-extinguishing behaviour describes whether burning continues after exposure or stops within the expected criteria. This helps show how the material may behave after a flame challenge.
A representative specimen is a sample that reflects the material, thickness, construction and features relevant to the intended battery enclosure application.
UL 2596 testing can support battery enclosure material programmes for EV battery packs, energy storage systems and lightweight polymer, composite or non-metallic housings.
UL 2596 planning should consider the material grade, thickness, reinforcement, coatings, joints and any representative features that may affect fire performance.
Early review is especially useful for polymer, composite, layered or 3D printed constructions where the final enclosure design may differ from a flat sample. The available or planned approach should be confirmed before it is quoted or committed.
Battery enclosure material projects often need early technical review before specimens are submitted for testing. Coordinating material information, sample geometry, application context and reporting expectations helps keep the evidence aligned to the wider battery safety programme.
For projects comparing multiple polymers, composites or non-metallic constructions, review the intended enclosure design before finalising the UL 2596 test route.
Outputs are agreed before the test so the evidence matches the programme need. A typical package may include:
Recorded temperature, pressure and agreed telemetry data
Recorded exposure conditions and agreed observations
Observations from setup, test execution and post-test review
Photographic evidence where agreed
Confirmation of material response against the agreed scope
An agreed test report or data pack aligned to the quotation scope
Share your material data sheet, enclosure drawings, sample details and target application. Resonate Testing can review the practical test route, specimen needs and reporting expectations before quotation.
Whether you’re looking to contact us for the first time or have another testing requirement, we’d love to hear from you.
