|DSM’s Stanyl and EcoPaXX are used in the new SIM-CEL EV prototype. Click to enlarge.|
SIM-Drive Corporation, founded by Hiroshi Shimizu and based in Kawasaki City, Japan, unveiled the SIM-CEL on 27 March—the third prototype of an advanced all-electric car incorporating in-wheel motors that the company has developed since it was founded in 2009. SIM stands for Shimizu In-wheel Motor, and CEL stands for Cool Energy Link.
The SIM-CELL features four in-wheel motors with combined maximum torque of 3,400 N·m (2,508 lb-ft)—850 N·m (627 lb-ft) per motor, up from 700 N·m (516 lb-ft) in the preceding concept. Maximum output is 260 kW (65 kW/motor). The Li-ion battery pack has a 29.6 kWh capacity; fast CHAdeMO charging up to 80% takes 1 hour.
Energy consumption in JC08 mode is 91.2 Wh/km. The SIM-CEL prototype has a range of almost 325 km (202 miles) on a single charge, and it can accelerate from 0 to 100km/h in 4.2 seconds. This performance is in part due to lightweighting technologies developed in collaboration with DSM and others.
Development of the SIM-CEL, which took around one year, involved close collaboration with 26 outside organizations, including DSM. DSM personnel were located at SIM-Drive’s development center on a full-time basis, and were actively involved in the prototyping process.
DSM contributed to the development of three parts for the SIM-CEL: a body panel in its EcoPaXX polyamide 410; a wheel cover center cap in the same material; and a heat sink for highly energy-efficient LED headlights in Stanyl TC polyamide 46.
EcoPaXX polyamide 410 is 70% resourced from the castor plant. It is certified 100% carbon neutral from cradle to gate.
Kees Tintel, who was responsible for development of EcoPaXX at DSM, says the new grade contributes to weight reduction in the SIM-CEL by replacing metal; the part is in fact at least 50% lighter than a metal version. EcoPaXX’s very good flow properties provide an excellent surface finish, and it has the necessary high temperature resistance to enable inline painting along with the rest of the vehicle. Unlike some other polyamides, it absorbs little water, and therefor has a very good dimensional stability. It also has sufficient elasticity to enable assembly with snap fits.
In order to improve overall aerodynamics, the SIM-CEL incorporates spats, or fender skirts, which cover the rear wheel arches. These are also made in DSM’s EcoPaXX polyamide 410, further contributing to the sustainability of the car, its low weight and its good aesthetics.
The SIM-CEL uses LED’s in its headlights in order to use as little electricity as possible. For the heatsinks of the LEDs, DSM developed a special thermally conductive grade of its high temperature resistant Stanyl TC polyamide 46. Stanyl TC551 has a surface thermal conductivity of 14 W/mK and a volume thermal conductivity of 2.1 W/mK.
Heat sinks are normally made in aluminium. Aluminium does have a much higher thermal conductivity than Stanyl—160 W/mK—but an all-aluminium heat sink would be over 25% heavier than the version on the SIM-CEL, which is a hybrid of Stanyl TC551 and aluminium. This hybrid shows practicable heat dissipation because aluminum and Stanyl have role sharing optimally. The design of the part was critical. Stanyl TC has very good flow, which enabled us to design a part with thin walls and a high surface-to-volume ratio to get very good heat dissipation.—Kenji Nishita, responsible for the development project at DSM
Separately, DSM opened its first application development technical center for engineering plastics in Japan on 26 March 2013 at the Yokohama Business Park in Yokohama City, Kanagawa Prefecture.