A Review on Thermal Behaviors and Thermal Management Systems for Supercapacitors

As a representative electrochemical energy storage device, supercapacitors (SCs) feature higher energy density than traditional capacitors and better power density and cycle life compared to lithium-ion batteries, which explains why they are extensively applied in the field of energy storage. While the available reviews are mainly concerned with component materials, state estimation, and industrial applications, there is a shortage of understanding of thermal behaviors and thermal management systems of SCs, which makes this review a timely aide for fulfilling this gap. This review introduces the energy storage mechanisms of SCs, followed by descriptions of current investigations of thermal behaviors. This covers the aspects of heat generation rates for electric double-layer capacitors (EDLCs) and hybrid supercapacitors (HSCs), together with reviewing existing experimental methods to measure and estimate heat generation rates, as well as comparative assessments of multiple heat generation rate models and research on thermal runaway. In addition, there are also overviews of current efforts by researchers in air cooling systems, liquid cooling systems, phase change material cooling systems, and heat pipe cooling systems. Finally, an in-depth discussion is provided regarding the challenges and future work directions for SCs in thermal behaviors and thermal management systems.