Some 6.6 million electric vehicles (EVs) were sold around the world in 2021. As such, current market trends are leading EV battery pack manufacturers to improve battery characteristics, design, and cost-efficiency, in order to aid their adoption by the mass market.
Chinese engineering plastics and new composite materials manufacturer Genius, together with graphene nanotube producer Ocsial, has developed an advanced engineering solution for battery packs. The technology uses reinforced glass fibre-filled polyphenylene sulfide (PPS), with 0.3 wt.% graphene nanotubes replacing 10 wt.% conductive carbon black. The final parts have shown surface resistivity of 103 Ohm/sq after injection moulding and reportedly “fully meet” the high lithium-ion battery standards.
Traditional agents added into thermoplastics have numerous drawbacks, increasing the number of out-of-spec parts and forcing producers to make compromises in performance. In short, carbon black cannot provide stable and homogenous electrical conductivity, while carbon fibre cannot provide targeted low resistivity.
“In contrast to conventional additives, graphene nanotubes used at an ultra-low effective concentration make it possible to preserve the outstanding chemical and thermal performance of high glass-filled PPS, including its dimensional stability at ambient conditions,” said Loyes Zhi, Managing Director of Sales and Commercial for Greater China & SEA, Ocsial Group.
“What’s more, they preserve the required MFI level and impact viscosity, thereby providing acceptable injectability, which is hard to achieve using multi-wall carbon nanotubes."
An easy-to-handle pre-dispersed concentrate of nanotubes, called Tuball Matrix, allows good processability and the freedom to incorporate other functional ingredients. Permanent homogenous resistivity without “hot spots,” retained colour, good surface quality, and high performance of the battery pack reduce the assembly costs of battery enclosures, increasing their safety, durability, compliance, and affordability, which are the major drivers in the EV market.