The worldwide adoption of electric and hybrid vehicles and associated technological innovations are driving the need for specialized materials that can meet the unique challenges of EV components. Resins used in EV construction include polyurethanes, epoxies, unsaturated polyesters, and silicones systems. Polyurethanes have the dominant share of this resin market segment because of their key product properties such as excellent thermal profiles, high flexibility, resiliency and vibration resistance, excellent tensile properties, superior adhesive properties, chemical and abrasion resistance, and durability. Polyurethanes also offer processing versatility in assembly of EV components. A CAGR's of 15-20% has been projected for polyurethane materials in this market.
The broad capabilities of polyurethanes help to reduce the overall weight of electric vehicles to enhance electric efficiency, extend vehicle range, and improve safety. The superior bonding properties of polyurethanes allow joining of dissimilar lightweight materials such as polymer composites, fiber reinforced polymers, low surface energy plastics, aluminum alloys and other metals.
Applications of polyurethanes in EV battery systems include the following:
Potting, encapsulation and gap fillers around battery cells
Adhesives for battery boxes
Thermally conductive adhesive formulations used in thermal management
Systems for bonding battery cells to thermally conductive plates
Mechanical impact and vibration protection; battery pads
Battery enclosures
Attributes of High-Performance Polyether and Polycaprolactone Polyols
With their exceptional versatility and performance characteristics, polyurethanes have gained significant adoption in EV applications. Advantages afforded by polyurethanes include:
Superior strength-to-weight ratios
Durability and resistance to wear, abrasion, impact and vibration
Oil, chemical, moisture, and corrosion resistance
Good adhesive characteristics
Performance over extreme low and high temperature ranges
Processing and design versatility
Potential to reduce the Product Carbon Footprint (PCF) of EV components
The soft segment of polyurethanes has a dominant effect on the performance parameters of polyurethane systems. The table below summarizes the relative performance of three generic classes of polyols used in polyurethane elastomers: polycaprolactones, adipate polyesters and polytetramethylene ether glycols (PTMEG). The designation of "Best-in-Class" refers to the highest performance within these three classes. The chart can assist the formulator in the selection of the best soft block class of polyols for EV material applications. The polycaprolactone and the PTMEG polyols represent the highest performance profiles of the polyol classes, while also exhibiting benefits against polyurethane processing requirements for EV materials. The low acid values, low polydispersity's and low viscosities of the polycaprolactone and PTMEG polyols afford numerous advantages over the general purpose adipate polyester polyols.