Battery Model Docs

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Battery Docs

The battery model has the following folders:

/maps/ - Contains performance maps for Samsung 18650-30Q Li-Ion Cells and Amprius Cells

/test/ - Contains tests for each file in the parent directory

• test_reg_thevenin_interp_group.py - Tests the interpolation scheme
• test_cell_comp - Tests the engineering calculations for battery performance
• test_battery_statics - Tests the battery pack sizing calculations
• test_battery_group - Tests proper inputs and outputs for connecting to the broader model, and calculations for both battery cell types
• test_battery_ODE - Tests a simple transient DYMOS run for 30 seconds

cell_comp.py

This explicit component converts the pack level current down to the cell current draw, then calculates the changes in SOC and Thevenin voltage states, as well as battery heat load and terminal voltage. It then calculates the total pack voltage and pack efficiency. This differs from the previous X-57 battery model, which splits thermal, performance, and pack calculations into separate components.

reg_thevenin_interp_group.py

This Strucutured MetaModel calculates the 4 performance map values (C_Th, R_Th, R_0, U_oc) based on the current temperature and state of charge (SOC)

battery_group.py

This group connects the above two components, promoting variables necessary for the broader model. A solver loop exists to converge the battery output voltage based on the power demanded by the motors. This differs from the previous X-57 battery model, which converges on power.

battery_statics.py

This explicit component sizes the battery in the initial static sizing model before the transient model is run. This sizing calculation iterates until the Maximum TakeOff Weight (MTO) of the entire vehicle converges.

battery_setup.py

This method sets up the battery model for integration with the DYMOS phase