Method and System to Simulate Battery Pack Key-Off Thermal Behavior after Aggressive Drive Cycles 2017-01-0626
When a driver completes an aggressive drive cycle on a hybrid vehicle, the High Voltage (HV) battery system may be at risk of exceeding the power limit temperature, due to continuous absorption of radiative and convective heat from the environment, such as from exhaust and pavement, even after key-off. In such a case, in the absence of active cooling, the vehicle may not be keyed-on until battery temperatures are reduced below critical values.
A transient thermal analysis is conducted on a HV battery system to simulate the key-off operation using an effective Computational Fluid Dynamics (CFD) methodology. Two stages are considered in this methodology to capture the complexity of the geometry and the multiple phenomena that need to be simulated in the model.
The introduced modeling technique can be used for Full Hybrid Electric Vehicle (FHEV) and Plug-in Hybrid Electric Vehicle (PHEV) transient key-off situations. When applied during the early design stages, the results from this analysis can significantly improve design robustness and performance, as well as help to identify potential issues that would otherwise not be found until much later in the development process.