How does Ansys workbench solver calculate the value of ECC (electric contact conductance) in thermal electric analysis?
ANSYS internally calculated maximum possible Conductance based on the underlying material properties. It depends on both Contact and target side material properties.
For example: If material A has conductivity (inverse of resistivity) which is more than both conductivity of B and C which are in a contact. ANSYS chooses maximum conductivity from underlying contact material (A in this case) and multiply it with 10000 to get a parameter '_maxCond'.
ECC = _maxCond / ASMDIAG
where _maxCond is the maximum electrical conductance defined in the model, and ASMDIAG is the diagonal of the overall geometry bounding box.
Please check the input file generated (ds.dat) for your model to see this formula.