There are a number of different battery cooling options, a close coupled phase change material is not going to cool the battery but absorb thermal energy if the cells get too hot.
A solid to liquid phase change material is packaged next to the cells. This temperature at which the material changes phase is normally set around 50 to 70°C so that it can essentially add thermal inertia to overheating cells.
There are a number of phase change materials:
- Paraffin wax is widely used based on its relatively low melting point
- high latent heat capacity
- chemical stable
- Hydrated salts are a class of PCMs that can be engineered to operate in a specific temperature window
- high latent heat capacity
- can be non-flammable
PCMs are often combined or embedded into other materials to stop them leaking and maintain contact with the battery cells.
Phase Change Materials (PCMs) Failure in Two-Wheeler Batteries
Experience in the field in Maximizing Battery Longevity shows that PCMs don’t work so well.
Many two-wheeler EV manufacturers adopted Phase Change Materials for passive thermal management. However, in our revival work, PCM-equipped batteries frequently exhibit localized thermal stress and early failure. This is largely due to PCM’s low thermal conductivity and heat dissipation limits in compact environments.
Why PCMs Fail:
- Heat remains trapped, damaging cells and elevating IR.
- PCM layers saturate quickly in high-load scenarios.
- Lack of airflow or external cooling prevents effective heat rejection.