Design of an Electric Powertrain for a Formula Hybrid Racecar

Abstract

The purpose of this senior thesis was to design and construct the high-power, high-voltage portion of the powertrain of a formula-style electric racecar for the Formula Hybrid Competition, part of the Society of Automotive Engineers (SAE) Collegiate Design Series. The powertrain was designed to maximize the performance of the car in terms of acceleration, handling, and endurance while meeting the rules of the Formula Hybrid Competition and the budget constraints of Princeton Racing Electric, the student organization behind the creation of this car. The safety of the driver and emergency rescue crews is prioritized in the design of the system. The powertrain utilizes Enerdel lithium-ion pouch cells to provide power for two motors that power the rear wheels of the car independently. Power is transferred from the motors to the wheels through a fixed gear ratio chain drive. The system operates at a nominal 88V and has a peak power of 80kW for short periods. Although the vehicle ultimately did not pass mechanical and electrical inspection and was unable to compete in the dynamic events, the powertrain was functional. The high-voltage portion of the powertrain, specifically the Battery Management System, was in violation of two Formula Hybrid rules that contributed to the failure to pass inspection. Unfortunately, the violations could not be rectified in time to compete. However, solutions were found to rectify the problems, and will be implemented on the 2016 Princeton Racing Electric car.