Requirements for the application of ECUs in e-mobility originally qualified for gasoline cars

Electronic control units (ECUs) are widely spread over the automotive industry with lots of applications. At this time more than 100 ECUs are used in a medium-sized vehicle. Development, test and qualification of ECUs are time and cost extensive. That is why they are often used in more than one generation and more than one model of vehicles. Present ECUs are developed and qualified for vehicles with combustion engines. Since the introduction of hybrid and fully electrical cars the requirements on the ECUs changed drastically. With respect to the engine ECUs temperature maxima is lower. On the other hand due to charging the batteries and other continuous voltage stresses, the time of operation (active and passive) is massively growing. The central question is: Is it possible to use ECUs qualified for gasoline car in electric cars without any reliability risks?To answer this question we start with a comparison of mission profiles of electrical cars and combustion engine cars. Based on the mission profiles we show the different requirements on the electronics robustness and use time. Afterwards we investigate the qualification process of an exemplary ECU from a combustion engine car and identify differences in comparison to the hybrid and fully electrical variant. As an example, a measurement of temperatures in a car driven under reasonably realistic conditions indicates the influence of the combustion engine on the thermal behaviour of the electronics as a key driver for failures. We provide a generic procedure that can be used for the design of future ECUs and compare it with expected temperature distributions in electric cars. Based on our results recommendations for the applicability of the use of existing ECUs in electric cars are discussed.