Battery Thermal Reduced Order Models

In a battery CHT simulation, the heat source could be either a constant or transient. A constant heat source could be used to study the worst-case scenario. It can also be used to compare the impact of different designs on temperature distribution. But if one wants to study the temperature profile during a transient loading condition, a transient heat source must be used, resulting in a transient CFD analysis. As such, a transient CFD analysis could consume a lot of computational resources. For such a transient application, under certain use cases and if certain conditions are satisfied, a Reduced Order Model (ROM) could be used to speed up the calculation by a few orders of magnitude.  

There are a few ROMs for the battery application. In this course, we are going to cover the LTI ROM and the SVD ROM. The LTI ROM gives information about cell average temperature or temperatures at user-specified locations. The SVD ROM gives temperature field. The LTI ROM is easier to use than the SVD ROM. You should start with the LTI ROM. Both ROMs are applicable only when the coolant flow rate is constant. 

ROMs in this course are created mostly from training data generated from a high-fidelity model, for instance, a high-fidelity CFD model. The LTI ROM could also be created based on training data from tests, a less popular choice in the battery application. This course focuses on how to use CFD to create the training data required for ROM generation and subsequent ROM usage. The ROM so created could be exported into 3rd party tools through FMUs or through direct state space matrices. Both processes are covered. 

Learning Outcomes:

Following completion of this course, you will be able to: 

• Create the training data for the LTI ROM using Ansys Fluent® fluid simulation software.
• Create a thermal LTI ROM for a battery module inside Ansys Twin Builder® simulation-based digital twin platform.
  • Create the training data for the SVD ROM using Ansys Fluent software. 
  • Create a thermal SVD ROM for a battery module inside Ansys Twin Builder platform. 
  • Post-process the SVD ROM results back in Ansys Fluent software. 
  • Export the ROMs into a 3rd part tool through FMUs or through direct state space matrices. 
  • Create the training data for the LTI+HTC ROM using Ansys Fluent software. 
  • Create the thermal LTI+HTC ROM for a battery module with transient flow rate.  

Prerequisites: 

• Basic knowledge of Ansys Twin Builder platform is useful.
• Familiarity with battery CHT analysis using Ansys Fluent software is desirable.

Please note: These training materials were developed and tested in the 2025R2 release.