ROMITRON® PPS FOR E-MOBILITY

New applications in electric vehicles (EVs) led to increased demand for polymers with higher thermal and electrical properties. Meanwhile, other features like electromagnetic interference (EMI) shielding and thermal/electrical conductivity are getting more attention. In hybrid electric vehicles (HEVs), downsizing of the combustion engine leads to local hot spots, which thermal management systems need to be able to handle. ROMITRON® PPS has interesting characteristics such as outstanding heat resistance (continuous service temperature 200 °C), inherent flame retardancy, and excellent chemical resistance to meet the challenging EVs requirements. The main drivers for ROMITRON® PPS in EVs/HEVs are expected as follows:
 
DEMAND FOR HIGH VOLTAGE PARTS
High voltage plastic parts need higher levels of flame retardancy and comparative tracking index (CTI), along with increased heat cycle/thermal shock resistance. Parts such as invertor and electric motor cores, housings, and capacitor cases need to withstand at elevated temperatures and have excellent heat cycle performance.
 
HIGHER DEMAND FOR THERMAL MANAGEMENT SYSTEMS
Compared to internal combustion engine cars, the thermal management systems in HEV/EVs support additional components such as lithium batteries, traction motor (operating temperature of coils up to 190 °C), high power electronic controllers, etc. Cooling pumps for the batteries and the electric motor operate in constant exposure to the water-glycol coolants. Battery cooling systems stay in use not only when driving but during charging cycles that extends coolant exposure time. Therefore, polymers with a higher level of chemical resistance are required. ROMITRON® PPS is an ideal choice for EVs thermal management applications due to its outstanding chemical and heat resistance.
 
DEMAND FOR METAL INSERT PARTS
EVs/HEVs have different parts to be injected with metal inserts. For example, high voltage busbars are thick copper bars overmolded with PPS due to its good flow and excellent electrical insulation.
 
In addition to standard glass fiber/mineral filled ROMITRON® PPS, ROMIRA develops ROMITRON® PPS blends and compounds reinforced with specialty fillers/additives. As an example, 30% short carbon fiber filled ROMITRON® EXP3159 offers high strength/rigidity and can add other effects such as EMI shielding to the injected parts. There are several EV parts in need of EMI protection over different frequencies such as battery and electronics housings, infotainment enclosures, ADAS and LiDAR housings, etc.

ROMITRON® EXP3159 can contribute to EMI protection along with highest flammability rating V-0 (0.8mm thickness). The use of carbon fiber facilitates heat transfer from sensitive areas as well. There is also the newly developed ROMITRON® EXP3178 grade with close to 35 % weight reduction comparing standard highly filled PPS GF/ M65. Thanks to ROMIRA’s long compounding experience and ultra-modern production facilities, re-processed carbon fiber and other lightweight fillers are incorporated in to the PPS matrix to achieve high levels of weight saving.