Lithium-ion batteries have become a staple of everyday life: from phones, to laptops, to bicycles, to the rapidly growing electric vehicle industry. However, thermal runaway continues to be a safety concern. Thermal runaway can be caused by overcharging, overheating, or mechanical damage and often result in fire propagating throughout the battery. The use of a phase change material (PCM) as an interstitial packing material for thermal management has been explored.
The thermal conductivity of the PCM was measured using a Modified Transient Plane Source sensor from C-Therm. It was found to have a thermal conductivity of 20 W/mK, compared to 2.5 and 0.024 W/mK for potting compounds and air respectively. With this, thermal runaway was instigated using nail penetration.
Results and Conclusion
PCMs were found to reduce the temperature of neighbouring cells after thermal runaway initiation. When short circuits were not initiated, cells without PCM insulation reached 189°C, compared to 109°C with PCM. Meanwhile, when short circuits did occur, tests without PCM fully propagated into violent fire. However, with PCM, propagation was prevented by conducting heat away from the cell, leaving neighbouring fuel cells below 120°C.
This experiment was carried out using C-Therm’s Modified Transient Plane Source sensor.
For more information on this experiment, see the full publication.