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Using Flexible Heaters for Thermal Runaway Testing

thermal runaway

Thermal runaway is a critical issue in the world of electronics, batteries, and energy systems. It’s not just a technical challenge—it can lead to system failure, fires, and even explosions if not properly managed. Understanding what thermal runaway is and how to test for it using flexible heaters is essential for engineers, product designers, and anyone working with high-energy systems.

WHAT IS THERMAL RUNAWAY?

Thermal runaway occurs when an increase in temperature causes a process or device to produce even more heat, which in turn accelerates the temperature rise. This self-reinforcing loop can quickly spiral out of control. It’s most commonly associated with lithium-ion batteries, where a failure in one cell can trigger a chain reaction of overheating in the others.

In systems like batteries, the internal temperature can rise due to:

      • Overcharging
      • External heat sources
      • Short circuits
      • Internal chemical reactions

As the temperature rises, it can break down internal components, release flammable gases, and ultimately ignite.

FLEXIBLE HEATERS FOR THERMAL RUNAWAY TESTING 

thermal runaway

While flexible heaters are most often used for thermal protection and management, they also play a valuable role in simulating heat-related failure scenarios, especially in battery safety testing.

Simulating Overheat Conditions

Flexible heaters can be applied to the surface of a battery pack or cell to intentionally raise its temperature during controlled testing. This allows researchers or engineers to:

      • Gradually increase temperature to test failure thresholds.
      • Evaluate at what point a battery cell vents, swells, or triggers a thermal runaway event.
      • Monitor sensor response times and control system behavior under thermal stress.

Example: A heater is attached to the exterior of a lithium-ion cell and ramped up to simulate ambient heating from a failed neighboring cell or an environmental heat source.

Triggering Localized Hot Spots

Because flexible heaters can be custom-shaped and zoned, you can create targeted heat zones to simulate hot spots that might cause uneven stress in battery packs or components—ideal for real-world simulation of failure points.

Example: Applying heat to one corner of a battery module to see how it affects thermal propagation to nearby cells.

Preconditioning for Cold Start Runaway Tests

Thermal runaway can be more severe when batteries are cold and then rapidly heated. Flexible heaters are used to pre-warm the test environment or battery to replicate such conditions. This is especially useful in:

      • EV and aerospace battery testing.
      • Cold-weather performance evaluation.

System Integration Testing

Flexible heaters can be combined with thermocouples, RTDs, and control circuits to test how a real-world thermal management system would respond to rising temperatures and potential runaway conditions.

This is useful for validating:

      • Cutoff controls
      • Software alarms
      • BMS (Battery Management System) responses

IMPORTANT CONSIDERATIONS

thermal runaway

      • Precision control is key. Use heaters with fine thermal control (low thermal mass, fast response).
      • Always include thermal fuses, sensors, or shutoff circuits during testing to prevent dangerous situations.
      • Perform testing in certified battery safety labs with proper ventilation, explosion-proof chambers, and fire suppression systems.

Flexible heaters are not just for protecting against thermal runaway—they’re also excellent tools for triggering and testing thermal failure scenarios in a controlled way. Their precision, customization, and ability to simulate localized heating make them indispensable for battery engineers and safety testing labs.

Contact TurboFlex Heaters to learn more about how we can help with your thermal testing and runaway protection.

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