Battery diagnostics and and operating strategy
Different strategies applied in vehicles (such as start/stop and energy recuperation) increase the stress for lead batteries during driving cycles significantly, thereby increasing the risk of failure. It is, therefore, essential to observe and estimate the state of the battery. For this purpose, a sensor attached to the negative pole of the battery is used to measure current, voltage and temperature. These measured signals are used by the diagnostic algorithm which is implemented on the micro controller integrated into the sensor. The algorithm estimates battery State-of-Charge (SoC), State-of-Health (SoH) and State-of-Function (SoF). This information is then made available to the energy-management-system of the vehicle to allow control of the operating strategy.
The SoC is the actual battery capacity given in percent relative to the maximum battery capacity. The SoH is a measure for the aging of the battery. SoF defines the performance capability of the battery, especially the cranking capability. In recent years, especially for electric vehicles, a new functionality has become more and more important: SSoF (Safety State of Function) – the estimation of the battery minimum voltage during a pre-defined discharge current profile.
The presentation will describe the methods used by the IBS (Intelligent Battery Sensor) algorithm for estimation of battery parameters and some of the actual challenges encountered related to battery safety functionalities.
Dr Adriana Traistaru works as a Model Based Software Engineer at Forvia (Hella) in Timisoara, Romania. She has been working for the company since 2018. In her present position she is responsible for lead battery monitoring algorithm development for different automotive projects. Between 2005 and 2018 Adriana was working at Continental Automotive Romania in Timisoara as a Software Engineer for automotive projects which involved Li-ion and lead battery diagnostic algorithm development and research activities. Before 2005 Adriana was working as Assistant Professor at ‘Politehnica’ University of Timisoara. Adriana has a PhD in electrical engineering in the field of Li-ion battery diagnostic algorithms and thermal modelling of Li-ion battery cells from the ‘Politehnica, University of Timisoara.