Developing a luxury electric vehicle (EV) from scratch with a short deadline demands organization and access to the right technology to get the job done. Lucid Motors of Menlo Park, California, met the first challenge by putting all the engineers in one room so the structural and aerodynamics engineers would know what the battery, motor and power electronics engineers were doing, right from the start. This collaborative environment has helped them to design a unique automobile with more passenger space by reshaping the battery stack, while optimizing the electric motor, the cooling system, the aerodynamics and the battery life.
Battery thermal management is crucial for high-power applications such as electric/hybrid vehicles. Modeling is an indispensable tool for designing better battery cooling systems. A fast and accurate battery thermal state space model (also known as an LTI model) can predict cell temperature under transient heat dissipation and mass flow rate. The state space model is first generated using computational fluid dynamics (CFD) results. Subsequently, the state space model is simulated inside ANSYS Simplorer to determine transient cell temperature. Two examples demonstrate the technology below. The first is an automotive battery module using cylindrical cells, and the second uses prismatic cells. Continue reading
Battery makers are concerned about the potential for fires in the lithium ion batteries used in the latest electric and hybrid vehicles. Two principle mechanisms have been identified that can lead to a cascading reaction known as thermal runaway which in turn can cause battery fires. The first is a short in a cell that may be caused by a crash impact or by an impurity. The second is a blockage or other malfunction in the cooling system that cools the cells by running coolant through microchannels in the battery. There are hundreds of different variables involved in battery design that interact in complex ways that can affect the potential for thermal runaway as well as having an important effect on the efficiency of the battery. Cell and pack makers perform a considerable amount of testing during the development process to investigate the impact of these variables but there is never enough time to come anywhere close to investigating the complete design space. Physical testing is also quite limited in its ability to evaluate battery performance under extreme conditions such as vehicle crashes. Continue reading