The
development of phase change material (PCM) for battery thermal
management poses key limitations on its reliability caused by leakage
and shape deformation under high temperature. In this work, a kind
of phase changeable and hydrophobic polymer skeleton is grown in situ
in a paraffin (PA)/expanded graphite matrix to obtain the leakage-proof
composite PCM (CPCM) at the kilogram-level. Benefiting from the additional
latent heat provided by the phase changeable alkyl side chains of
the polymer skeleton, the obtained CPCM shows a high latent heat of
120.3 J g–1 coupled with a thermal conductivity
of 2.92 W m–1 K–1. Most importantly,
the three-dimensional cross-linking main chain and the hydrophobic
alkyl side chains endow the obtained CPCM with extraordinary shape
stability under high temperatures up to 250 °C and high PA adsorbing
capability, respectively. As a consequence, the CPCM presents excellent
antileakage performance for the battery module (21 V/16 Ah) under
harsh working conditions, i.e., 50 charge–discharge cycles
at 3C–4C, thus giving rise to a durable cooling performance.
The maximum temperature (T
max) and temperature
difference (ΔT
max) of the battery
module can be controlled constant at 50.9 and 5.0 °C during the
cycles, respectively. By stark contrast, owing to the obvious leakage
phenomenon, the battery module with traditional CPCM adopting a classical
low-density polyethylene skeleton shows increasing T
max and ΔT
max during
the cycles.