Self-Regulating Polymer–Carbon Nanotube Composite Heater on Meta-Aramid Textile

Electric vehicles (EVs) lack a substantial source of recoverable powertrain waste heat, making cabin heating a direct parasitic load on the battery and thereby increasing the need for efficient and spatially distributed thermal management strategies. In this study, a flexible self-regulating surface heater was developed by integrating a polymeric positive temperature coefficient (PTC) multi-walled carbon nanotube (MWCNT) composite with a flame-resistant meta-aramid textile substrate. The principal contribution of this work is the systematic control of the PTC:CNT ink ratio to correlate CNT-mediated conductive-network formation with the average temperature coefficient of resistance (TCR) and electrothermal self-regulation, together with its implementation in a thermally robust textile architecture for elevated-temperature operation. Among the investigated ink ratios of 95:5–80:20, the 90:10 formulation provided the most favorable balance between electrical conduction and PTC response, reaching a stable temperature of approximately 130 °C at 24 V without thermal runaway. The optimized heater retained stable electrical functionality after repeated bending and washing, while the meta-aramid substrate provided improved resistance to ignition under severe thermal exposure. A cabin-mimicking chamber experiment further demonstrated the system-level heating capability of the textile heater under controlled power-input conditions. These results demonstrate that composition-controlled PTC-CNT network engineering on thermally robust textiles provides a viable approach to flexible and self-regulating heating systems for EV thermal management.