Batteries & Battery Packs
ISO 22007-2 · ASTM E3088 · ASTM D7984 · ASTM D5470 · ISO 8301
Ideal Instruments for Battery Thermal Properties: Cells, Interfaces and Barriers
Battery thermal design needs three kinds of data: the thermal properties of cells and pack materials, the resistance of the interfaces between them, and the high-temperature performance of the barriers that separate cells. C-Therm covers all three, led by the Trident.
Test from Cell to Component
Measure intact coin, pouch, prismatic and cylindrical cells, plus electrodes, separators, adhesives and insulation, with no teardown.
Measure Anisotropy
Axial (through-plane) and radial (in-plane) thermal conductivity in a single measurement.
Heat Capacity Measurement
Measure specific heat capacity on full cells, without disassembly or sample coupons.
Thermal Impedance Under Compression
ASTM D5470 thermal resistance of gap fillers, pads, pastes and adhesives at up to 2 N/mm².
Precise Bond-Line Measurement
Optical gap measurement at 0.1 µm resolution corrects for compression and thermal expansion.
Contact Resistance & Delamination
Separate interface resistance from bulk, and find the force or gap at which adhesion fails.
Thermal Barriers up to 850 °C
Cell spacers, mica, aerogels, fumed silica and foams, from 25 °C to 850 °C.
Insulation Under Pack Compression
Up to 4 N/mm², with force and compression recorded, for soft foams and rigid boards.
Simulate Real Heating Profiles
Gradual or rapid heating to reproduce operating and extreme conditions.
Compare all three instruments in the technical specifications table.
Why Thermal Conductivity Matters for Batteries and Battery Packs
Every battery turns part of its energy into heat. Whether that heat leaves the cell or builds up inside it depends on thermal conductivity (k), heat capacity and the path the heat must travel through electrodes, separators, casing, adhesives and cooling hardware.
The push for higher energy density, faster charging and higher C-rates means more heat, generated faster, in tighter packs. Silicon anodes, solid-state electrolytes, cell-to-pack designs and eVTOL duty cycles all move the thermal limits. Poor heat removal accelerates ageing, cuts capacity and cycle life, and in the worst case allows thermal runaway to propagate from cell to cell.
Thermal conductivity data is used in:
- Electrochemical-thermal models, of cells and modules, where axial and radial k, diffusivity and heat capacity set temperature gradients during fast charge and high-rate discharge.
- Thermal runaway and cell-to-cell propagation modelling, where the conductivity of barriers, insulation, potting and PCMs decides whether a neighbouring cell reaches its trigger temperature.
- Battery thermal management system (BTMS) design, including cold plates, heat spreaders, gap fillers and thermal interface materials.
- Materials development and QC, from electrode coatings and separators to adhesives, tapes and pressure-sensitive adhesive films.
A jelly roll or stacked cell is layered and strongly anisotropic. Through-plane conductivity across the layers is typically far lower than in-plane conductivity along the current collectors. A single isotropic value, or a value calculated from the datasheets of individual layers, will misstate how heat moves through the real cell.
Measuring the finished cell and the actual pack materials gives representative
inputs for models, design decisions and safety assessments.
Which Battery Application Are You Characterizing?
Cylindrical, Pouch, Prismatic & Coin Cells
thermal conductivity · thermal conductivity · cylindrical cell axial/radial thermal conductivity · pouch cell · prismatic cell · coin cell · anisotropic battery thermal conductivity · battery heat capacity
Cell models need the thermal properties of the cell as manufactured. A wound or stacked cell conducts heat well along its current collectors and poorly across its layers, so a single number is not enough. The Trident measures axial (through-plane) and radial (in-plane) thermal conductivity on finished 18650 and 21700 cylindrical cells using single-sided TPS with the Anisotropy Utility, and on pouch and prismatic cells using the TPS Bulk and Anisotropy utilities.
The Specific Heat Utility measures Cp on the full cell, no disassembly or coupons, and that value feeds directly into the anisotropy calculation. One instrument delivers the complete set of model inputs: k-axial, k-radial, diffusivity and heat capacity.
Battery cells generating heat during operation
Electrodes, Separators, Electrolytes and Solid-State Materials
cathode · anode · silicon anode battery · battery separators · electrolytes · solid-state battery · solid electrolyte · electrode coating thermal conductivity
Cell-level behaviour starts with the layers. Electrode coatings change with active material, binder, conductive additive and calendering density. Separators and ceramic coatings are thin and anisotropic, and solid electrolytes bring new interfaces. The TPS Thin Film and Slab utilities measure thin layers and coated foils directly, while MTPS and THW measure liquid electrolytes and electrode slurries in seconds.
This lets materials teams compare formulations, track the effect of silicon loading or calendering, and build the layer-by-layer data that cell designers need.
Coating weight, calendering density and binder choice all change the thermal conductivity of an electrode.
Battery Pack Thermal Management Materials
battery enclosure thermal management · battery cooling · gap filler · potting compound · thermal adhesive · pressure-sensitive adhesive film · insulation panels · heat spreader · phase change material · thermal runaway barrier · cell-to-cell spacer · mica · aerogel
In a pack, heat leaves the cells through structural adhesives, gap fillers and cold plates, and is blocked by insulation and runaway barriers between cells. Each material has the opposite job, high k to remove heat or low k to stop propagation, and each must be verified after cure, under compression and across temperature.
Each material needs the right test. The Trident’s MTPS sensor screens gap fillers, potting and adhesives in seconds and picks up filler sedimentation and agglomeration, while the TPS Thin Films Utility measures 75 µm and 150 µm pressure-sensitive adhesive films directly, without stacking layers. The ZFW TIM-Tester measures thermal resistance of gap fillers, pads and pastes at the real bond line under compression, per ASTM D5470. For insulation and cell-to-cell barriers, the High-Temperature Heat Flow Meter measures thermal conductivity from 25 °C up to 850 °C under pack compression. See also the Thermal Interface Materials application page.
Electric Vehicles, Energy Storage, eVTOL and Drones
EV battery pack · cell-to-pack · battery pack hotspot analysis · cell-to-cell thermal propagation · stationary energy storage · eVTOL battery · DO-311A thermal runaway testing · drone battery heat dissipation · high C-rate pouch cell · battery swelling
Every application puts the same question to its battery: can heat leave the cells fast enough? EV and stationary storage packs are judged on range, charge time, lifetime and safety, all of which depend on keeping cells within a narrow temperature window. eVTOL and electric aircraft face very high discharge rates at take-off and landing, strict thermal runaway containment requirements such as RTCA DO-311A, and a weight budget where every gram of barrier and insulation counts. Drones and portable devices pack high-rate pouch cells into small, sealed enclosures with little room for cooling, where trapped heat shortens life and causes swelling.
Measured cell anisotropy, heat capacity and material thermal conductivity, including barrier performance at temperatures up to 850 °C, let engineers locate hotspots, size cooling, compare lightweight barriers and model cell-to-cell propagation before building hardware. See also Automotive & Electric Vehicles.
See It in Action
Request a demonstration to see the C-Therm Trident measure the thermal conductivity and heat capacity of a finished battery cell, the ZFW TIM-Tester measure gap filler thermal resistance at a real bond line, or the High-Temperature Heat Flow Meter test thermal barriers up to 850 °C. Send us your cell format or material and we will show you the data.
Customer Success Stories
-
Beam Global
The C-Therm Trident Thermal Conductivity instrument is great. We are able to look directly at thermal conductivity quickly of phase change composite materials for lithium-ion battery packs. There are no special coatings required with the system. It was half the price, and it is really easy to use compared to traditional LFA. It is a triple win. We use it weekly in characterizing our materials.
Dr. Samuel T. PlunkettPhD, Director of Battery Technology
-
Intel Corporation
C-Therm’s Trident system allows us to not only test a relatively broader range of materials with various sensor techniques, but with the slab utility we are able to easily test the thermal conductivity of our thin film aluminum alloys – which have high value in today’s electronic computing and hardware.
Hardeep SinghSr. Thermal Engineer
-
MG Chemicals
Adding the Trident system to our lab this year has resulted in more efficient thermal conductivity measurements, and we have begun to integrate it into our quality control process to great success.
Alexander HudsonResearch and Development Manager
Batteries & Battery Pack Materials Webinars and Technical Videos
-
Webinar: Thermal Conductivity Testing of Pressure Sensitive Adhesives for EV Systems
-
Webinar: High Temperature Heat Flow Meter: Measuring Thermal Conductivity of Thermal Barrier Materials
-
Webinar: Solving Formulation Challenges of Thermally Conductive Materials in E-Mobility (with Epic Resins)
-
Webinar: Thermal Performance Testing of Batteries and Related Thermal Management Systems with H.E.L Group
-
Webinar: Preventing Thermal Runaway Propagation in Lithium Ion Battery Packs Using a Phase Change Composite Material
-
Webinar: Characterizing Phase Change Materials for Improved Battery Thermal Management
Application Resources
-
Trident™ Thermal Conductivity Application Highlight: Accelerated Performance Validation of Thermal Adhesives for EV Battery Packs
-
Trident™ Application Highlight: Thermal Conductivity of Self-Adhesive Tapes for EV Applications Using MTPS
-
Trident™ Application Highlight: Anisotropic Thermal Conductivity Characterization of Cylindrical Battery Cells
-
Trident™ Application Highlight: Specific Heat Capacity Characterization of Battery Cells Using the TPS Cp Utility
-
Trident™ Application Highlight: Anisotropic Thermal Conductivity Characterization of a Lithium-Ion Pouch Cell
Thermal Conductivity Instruments & Sensors for Battery & Battery Pack Materials Testing
-
C-Therm Trident thermal conductivity instrument for battery cells and pack materials
-
MTPS single-sided sensor for fast thermal conductivity screening of gap fillers, potting compounds, adhesives and PCMs (ASTM D7984)
-
Flex TPS sensors (Ø6, Ø13 and Ø30 mm) for intact battery cells, electrodes and separator films (ISO 22007-2)
-
ZFW TIM-Tester – thermal resistance of gap fillers and pads between battery cells and cold plates (ASTM D5470)
-
High-Temperature Heat Flow Meter – thermal conductivity of cell-to-cell barriers and pack insulation up to 850 °C
-
Measuring the thermal conductivity of a sample using the TPS sensor.
-
Trident with the Automated Thermal Control (ATC) – simplifies elevated-temperature thermal conductivity testing
-
High-Temperature Battery Separator for EV applications.
-
Electrochemical cell: anode, separator, cathode and electrolyte layers set the cell’s through-plane thermal conductivity
-
Swollen lithium-ion cells, a result of heat build-up and poor thermal management
-
Dedicated Account Manager: To provide personalized support and expert guidance from quotation to final delivery.
Technical Specifications: C-Therm Instruments for Battery Testing
| Specification | Trident · MTPS | Trident · Flex TPS | ZFW TIM-Tester | High-Temp. Heat Flow Meter |
|---|---|---|---|---|
| Measurement Method | Transient, single-sided | Transient, single- or double-sided | Steady-state, stationary cylinder | Steady-state heat flow |
| Battery Applications | Gap fillers, potting compounds, adhesives, PCMs, insulation, electrolytes, slurries, powders | Intact coin, pouch, prismatic and cylindrical cells; electrodes, separator films, heat spreaders | Gap fillers, gap pads, thermal pastes, adhesives and tapes between cells and cold plates | Cell-to-cell barriers, mica, aerogels, fumed silica, ceramic nonwovens, foams |
| Measured Properties | Thermal conductivity, effusivity | Thermal conductivity (incl. axial/radial), diffusivity, heat capacity | Thermal resistance, impedance, effective conductivity, contact resistance | Thermal conductivity, thermal resistance, compression behaviour |
| Thermal Conductivity Range | 0.01–500 W/m·K | 0.005–2000 W/m·K | Derived from thermal resistance and bond-line thickness | 0.01–3 W/m·K |
| Volumetric Heat Capacity | Up to 5 MJ/m³·K* | Up to 5 MJ/m³·K | — | — |
| Temperature Range | −50 to 200 °C | −200 to 600 °C | 10 to 150 °C (hot side to 175 °C) | 25 to 850 °C |
| Applied Pressure | With Compression Test Accessory | — | 0.05–2 N/mm² | Up to 4 N/mm² |
| Test Time | 0.8–3 s | 10–600 s | Steady-state per set point | Steady-state per set point |
| Precision / Reproducibility | Better than 1% | Better than 2% | Better than 1 mm²K/W | On request |
| Accuracy | Better than 5% | Better than 3% | Gap ±4 µm (0.1 µm resolution) | On request |
| Sensor / Sample Size | Ø18 mm sensor | Ø6, Ø13, Ø30 mm sensors; more sizes available | Gap 0–10 mm | Thickness 0.1–25 mm |
| Utilities / Modes | Liquids & Powders Cell; Compression Test Accessory | Bulk, Anisotropy, Slab, Thin Film, Specific Heat (Cp) | Pressure- or gap-controlled; delamination test | Gradual or rapid heating |
| International Standards | ASTM D7984 | ISO 22007-2, ISO 22007-7, ASTM E3088 | ASTM D5470-17, IPC-TM-650 2.4.54 | ASTM D5470, ISO 8301 |
*Calculated parameter
Frequently Asked Questions
The C-Therm Trident is a thermal conductivity instrument used by battery developers to measure finished lithium-ion cells and their components. Its Flex Transient Plane Source (TPS) sensor, compliant with ISO 22007-2 and ASTM E3088, measures the axial and radial thermal conductivity, thermal diffusivity and specific heat capacity of coin, pouch, prismatic and cylindrical cells, including 18650 and 21700 formats, without disassembly. On the same platform, the Modified Transient Plane Source (MTPS) sensor (ASTM D7984) screens gap fillers, adhesives, potting compounds and PCMs in under three seconds. For interface resistance and high-temperature barrier testing, C-Therm also offers the ZFW TIM-Tester and the High-Temperature Heat Flow Meter.
To discuss your cells, contact us or book a demo with one of our experts.
It depends on what you are testing. The C-Therm Trident measures intrinsic thermal conductivity, anisotropy and heat capacity of cells, electrodes, separator films, electrolytes and pack materials using transient methods (ISO 22007-2, ASTM E3088, ASTM D7984), and is the starting point for most battery R&D and QC. The ZFW TIM-Tester measures thermal resistance and impedance of gap fillers, pads, pastes and adhesives at the real bond line under compression, per ASTM D5470. The High-Temperature Heat Flow Meter measures thermal conductivity of cell-to-cell barriers and insulation from 25 °C to 850 °C under compression. Together they cover the cell, the interfaces around it and the barriers between cells.
To discuss the most appropriate instrument, contact us or book a demo with one of our experts.
Use a transient method for material conductivity and ASTM D5470 for thermal resistance under compression. On the Trident, MTPS (ASTM D7984) measures cured gap fillers, potting compounds, adhesives and pastes from a single-sided contact in 0.8–3 seconds, and is sensitive to filler sedimentation and agglomeration, which makes it suited to formulation screening and incoming QC. The Compression Test Accessory adds controlled load. Flex TPS (ISO 22007-2) measures pads, sheets and anisotropic materials, and its Thin Film Utility measures adhesive films as thin as 75 µm without stacking.
For bond-line thermal impedance, the ZFW TIM-Tester follows ASTM D5470. See the Thermal Interface Materials page.
The C-Therm Trident with the Flex TPS Anisotropy Utility. TPS under ISO 22007-2 calculates in-plane (radial) and through-plane (axial) conductivity from one measurement when the sample’s volumetric heat capacity is known. The Trident’s Specific Heat Utility measures that heat capacity on the same full cell, so both inputs come from one instrument. Pouch and prismatic cells are measured in the bulk configuration; 18650 and 21700 cylindrical cells are measured with the single-sided TPS configuration on the cell surface.
An engineer screening PCMs, insulation and runaway barriers needs results across a wide conductivity range, in solid and liquid states, and at temperature. The Trident covers 0.005 to 2000 W/m·K across its sensors, so the same instrument measures a 0.02 W/m·K aerogel barrier and a 20 W/m·K PCM composite, and MTPS measures PCMs above and below their melting point without changing sensors. For barriers that must perform during a thermal propagation event, the High-Temperature Heat Flow Meter measures thermal conductivity from 25 °C to 850 °C under compression up to 4 N/mm², on samples 0.1 to 25 mm thick. Published thermal runaway propagation studies have used C-Therm’s MTPS sensor to characterize PCM composites that kept neighbouring cells below 120 °C after nail penetration.
To discuss your materials, contact us or book a demo with one of our experts.
There is no thermal conductivity standard written specifically for battery cells; the method standard is chosen by sample type. ISO 22007-2 and ASTM E3088 cover the Transient Plane Source method for cells, electrodes, separators, pads and other solids, including anisotropic samples. ISO 22007-7 covers additional TPS configurations. ASTM D7984 covers MTPS for gap fillers, pastes, adhesives, PCMs, liquids and powders. ASTM D7896 covers transient hot wire for liquid electrolytes and coolants. ASTM D5470 and IPC-TM-650 cover steady-state thermal resistance of interface materials, as measured by the ZFW TIM-Tester. ISO 8301 covers the heat flow meter method used by the High-Temperature Heat Flow Meter for insulation and thermal barriers. Abuse and runaway standards such as UL 9540A and RTCA DO-311A define safety tests; they do not measure thermal conductivity, which is an input to the models those tests validate.
Yes. TPS measures finished coin, pouch, prismatic and cylindrical cells through their casing, and the Specific Heat Utility measures Cp on the full cell. No teardown, no coupons and no change to the cell’s internal structure, so the same cell can be measured again after cycling or ageing.
Because a cell is a stack of very different layers. Heat flows easily along copper and aluminium current collectors and poorly across separators and electrode coatings, so radial and axial conductivity can differ by an order of magnitude or more. A single isotropic value in a thermal model misplaces hotspots and misjudges how fast heat reaches the cooling surface. Measuring both directions gives the model the cell as it is built.
The TPS Specific Heat (Cp) Utility measures specific heat capacity on whole cells at the test temperature, without disassembly. It has been demonstrated on a 3.8 V lithium-ion pouch cell and a 21700 cylindrical cell. Cp tells you how much heat a cell can absorb before its temperature rises appreciably, which matters for fast charge, high-rate discharge and runaway onset, and it supplies the volumetric heat capacity needed for anisotropic conductivity.
Have questions about using the Trident for your specific materials? Contact us or book a demo with one of our experts.
Yes. The TPS Thin Film and Slab utilities measure thin layers, coated foils and separators directly. Liquid electrolytes and electrode slurries are measured with MTPS and the Liquids & Powders Cell or with the THW sensor. Solid electrolyte pellets and films are measured with TPS bulk or thin film configurations, depending on thickness.
Yes. The Trident’s TPS sensor covers −200 °C to 600 °C and MTPS covers −50 °C to 200 °C; Automated Thermal Control runs from ambient to 300 °C and the thermal chamber from −73 °C to 200 °C, so a temperature series can be generated on the same sample and fed to the model as a function rather than a single point. For thermal barriers and insulation, the High-Temperature Heat Flow Meter extends testing to 850 °C, and the ZFW TIM-Tester measures interface materials from 10 °C to 150 °C.
Laser flash (ASTM E1461) measures diffusivity on small, thin, often coated discs, so a cell must be cut apart, and conductivity also needs separate density and Cp data. Guarded hot plate (ASTM C177) needs large flat specimens and hours to reach steady state. Neither measures a finished cell. TPS on the Trident measures the intact cell in seconds to minutes and reports conductivity, diffusivity and heat capacity together, while MTPS adds a fast QC route for pack materials.
You may contact us or book a demo with one of our experts to discuss the details.
Thermal conductivity (k, W/m·K) describes how readily heat flows through the cell or material, and sets how fast heat reaches the cooling surface. Thermal diffusivity (α, mm²/s) describes how quickly a temperature change spreads and governs transient heating during a fast-charge pulse. Specific heat capacity (Cp, J/kg·K) describes how much heat the cell absorbs per degree of temperature rise. They are linked by k = α · ρ · Cp, and a battery thermal model needs all three.
Have questions about your cells or pack materials? Contact us or book a demo with one of our experts.