Not only can electric cars prevent local emissions, they can also be fun. Founded in 2012, E.Stall Esslingen is using electric racing cars to participate in various international events for Student Formula. One of the biggest events is the German Student Formula, which is held annually at the Hockenheim ring stadium.
The design of the traction battery of a racing car is very demanding. It is one of the most important components during the race: it determines whether the driver has enough power to defeat the competition.
Since the 2018 racing season, Covestro has been providing flame retardant materials to the E.Stall Esslingen team for building batteries. At its Leverkusen pilot plant, plastics makers extrude sheets from Bayblend PC / ABS (polycarbonate / acrylonitrile-butadiene-styrene) alloys to produce frames and brackets for its battery modules. These modules are based on so-called pouch-type lithium-ion batteries.
In the Department of Battery Design, Esslingen University of Applied Sciences students complement each other, from electrical engineering to electronics and mechanical engineering. In addition, the student formula provides certain design requirements for students in its regulations, which involve the safety of handling lithium-ion batteries. In addition to the active monitoring and control of the battery, the student formula rules clearly require the use of flame retardant materials, meet the flame retardant standards of the underwriters laboratory, and meet the UL 94 V-0 flame retardant standards in general technical requirements.
Raphael Raff, who is currently in charge of the E.Stall Esslingen high voltage sub-project, explained: "We are pleased that Covestro will support us again in the use of polycarbonate blend boards in the 2019 season." Compared to the previous year, the racing team Together, the company ’s BayBlend product experts chose a PC / ABS blend with about 10% lower density and high mechanical, electrical, and thermal properties in order to remove more weight from the car's battery.
For mass production, designers are looking for materials that meet the stringent requirements of automotive manufacturers for in-vehicle operation but are easy to process. Compared with semi-crystalline materials, the advantages of amorphous plastics such as polycarbonate are that they have almost no shrinkage during injection molding and have very low water absorption. This helps to design thin-walled, distortion-free parts. In addition, polycarbonate can provide very good flame protection. Covestro's product portfolio includes a large selection of flame retardant materials that meet UL 94 V-0 underwriters laboratory standards.
Covestro continues to develop its portfolio of battery applications. For battery holders used to house cylindrical batteries, pouch battery frames, battery cases and similar applications, focus on unfilled (Bayblend FR3010, BayBlend FR3040) and mineral filled (Bayblend FR3020, Bayblend FR3021) flame retardant products, as well as fiberglass Reinforced (BayBlend FR3060 EV) flame retardant products. Covestro also offers a thermally conductive polycarbonate grade from the Makrolon TC product line for battery thermal management.