Conclusions To improve safety performance and prevent catastrophic failure of battery packs, a state-of-the-art compressible battery pad made of polyurethane was re-engineered. At worst-case scenario when the cell is fully charged, experimental results indicate the pad itself is not able to mitigate cell-to-cell thermal runaway propagation.
Polyurethane (PU) foam is the baseline material, designed to hold components of EV battery packs in place and to provide vibration isolation and cushion expansion and contraction of pouch cells during their service life. A few approaches of engineering PU foam were employed to enhance its safety feature, which can be summarized as follows:
Table 1 lists the foam pads used in this study. Polyurethane (PU) foam is the baseline material, designed to hold components of EV battery packs in place and to provide vibration isolation and cushion expansion and contraction of pouch cells during their service life.
There are several types of foam commonly utilised in EV battery manufacturing. Let’s explore a few: Polyurethane foam, known for its exceptional thermal insulation properties, acts as a protective layer around the battery cells. It offers excellent temperature control, safeguarding the batteries from overheating during operation.
Polycarbonate/polyester-based PU possess high voltage tolerance, which can be designed for high voltage batteries. However, the low ionic conductivity of them needs to be solved first. Polysiloxanes are more suitable to be employed as copolymerization segments to modify the ionic transport and thermal performance of PU-based PEs.
A two-component, ultra-low density, flame-retardant polyurethane foam is designed for potting and encapsulating lithium-ion battery cells in EV battery modules. image courtesy of H.B. Fuller.