Flexible phase change composites with multiple colors and reversible thermochromic for temperature indication and battery thermal management

In this paper, a series of silicone rubber (SR)/thermochromic microcapsules (TC@MF)/cuprous oxide (Cu2O) flexible phase change composites (STC) with multi-colors and reversible thermochromic were prepared. In this composite, SR was used as polymer matrix and TC@MF with phase change enthalpy of 193 J/g was used as functional filler. Moreover, different contents of Cu2O were introduced to change color of composites and improve thermal conductivity and photothermal conversion. The STC composites could undergo reversible color changes from blue-violet to red with a color change temperature of approximately 52 °C. And it exhibited excellent leakage resistance with the leakage rate of STC-2 as low as 0.41%. The thermal conductivity of the STC-3 composite reached 0.33 W m−1 K−1 at Cu2O content of 9 phr. The STC composites were applied to dissipate heat from the battery and the maximum surface temperature was only 49.0 °C at 9.8 A discharge rate which represented 24.03 % reduction in surface temperature compared to the bare battery. This work offers an effective route for preparation of battery thermal regulation materials based on thermochromic microcapsules, which has significant potential for application in the field of battery thermal management.