How engineering plastics are powering electric vehicle growth
As consumer acceptance of electric vehicles continues to rise, the need for equivalently advanced material solutions in growing. A combination of changing consumer preferences, government policies and plastics innovations are helping to accelerate their growth.
Consumer attitudes toward electric vehicles are gradually changing, even in difficult markets such as the United States where inexpensive petroleum and range anxiety steer consumer preference toward larger internal combustion engine vehicles.
In a 2018 driver survey conducted by the American Automobile Association (AAA), 20 percent of Americans say they're likely to buy an electric car in the future. This is up from 15 percent in 2017, and the largest increase versus previous surveys. In the same survey, common driver concerns such as a lack of charging stations decreased 9 percent since 2017.
Tighter emissions regulations, dropping battery prices, better charging infrastructure and longer driving ranges are expected to increase electric vehicle (including hybrid, plug-in hybrid, battery electric and fuel cell) sales to 15% of total new vehicle sales in 2025, with the peak demand occurring in mega-cities where emissions regulations will be the most stringent.
In addition, regulations put into place by the Chinese government on the battery range and number of electric vehicles are creating a big push for electrification in automotive. While Chinese manufacturers have a competitive edge due to a combination of access to the raw materials needed for vehicle electrification, as well as their leading global position in batteries, this power play is forcing foreign manufactures that want to do business in China to invest heavily in electrification.
Lithium ion batteries
Problem: Lithium ion batteries (LiBs) are composed of multiple interconnected cells stacked inside a housing, with an electrical control unit that drives the cells and protects them from overloading or charging too fast. The battery cell housing ensures that each battery remains in position to withstand vibration, impact and other harsh conditions. Since the individual cells are connected via busbars safeguarded by fuses, mechanical stability of the total system is essential.
Solution: DSM’s Xytron® grades provide high dimensional stability, best-in-class chemical and temperature resistance, intrinsic flame retardance, and high thermal conductivity to ensure that the heat generated within the cells is conducted away to the active and/or passive heat sink of the module. Our breakthrough innovation in PPS polymer science eliminates the typical flash formation during injection molding to enable good processability with no rework required after molding.
Problem: Electric vehicles require high-voltage charging and interconnection systems to enable sufficient power to drive the main e-motor, and acceptable battery charging times. Yet, with high voltages, engineers need to take extra care in the design of parameters such as dielectric strength, creep, tracking resistance, and dedicated color coding to enable safe handling by operators, as well as first responders in the event of an accident.
Solution: DSM offers a wide range of flame retardant plastics that deliver the required electrical performance, with Comparative Tracking Index (CTI) of more than 600V, dielectric strength of more than 30kV, and a Relative Temperature Index (RTI) of 140°C.
Based on the materials Akulon® PA6, PA66, PA 46, or ForTii® PPA, these materials offer the high mechanical strength of polyamides, and work with a variety of assembly designs – including press fit, wave soldering, and reflow soldering. These compounds are halogen free, and free from red phosphorous, so that they can achieve the high CTI required for these applications. Additionally, by avoiding any ionic heat stabilizers, we have ensured full protection against potential electric corrosion of assembly bins or critical aluminum bonding wires within semiconductor chips. Our compounds are available in a variety of colors, including the orange color used to denote components directly in the high voltage system.
Connected autonomous driving
Problem: To ensure safe and reliable operation during the use of the vehicle, as well as throughout the manufacturing of parts through the various tier processes, connectors need to meet the following requirements:
- Unlimited shelf life (JEDEC MSL1)
- No pin corrosion (insulation material free from halogens and red phosphorous, and without ionic heat stabilizers)
- High continuous use temperatures of 150-180°C
- Excellent chemical resistance
- High ductility
- High electric strength and CTI (PLC0).
Solution: DSM’s dedicated ForTii product line addresses these diverse needs. Our best-in-class material solutions, ForTii JTX2 and ForTii Ace JTX8, combine the best of two plastics worlds. They combine the dimensional stability and low moisture absorption of polyesters together with the high mechanical strength of polyamides.
ForTii Ace JTX8 is the only material available around the world that meets JEDEC MSL1, while ensuring zero blistering over an infinite shelf life. And with the highest mechanical strength, it ensures excellent reliability during and after assembly, as well as after years of use in harsh conditions. These environment-friendly grades are free from halogen, red phosphorous, and ionic heat stabilizers. We also offer ForTii T11, a UL94-V0 @ 0.2mm alternative materials that delivers the highest level of flame retardancy.