A basic model for evaluating a direct battery and supercapacitor parallel connection

Ongoing research regarding the long-time effect of a supercapacitor-battery parallel connected system as compared to a battery only system, proved the usefulness of a model for such systems. The model, as created, enables evaluation of the direct response to a current load and as a consequence the dimensioning of the supercapacitors. The model does not predict the long term effect on the batteries in such a combination.
Integrated in a user friendly National Instruments LabVIEW program, which can import a current load profile, the model can calculate the response to such a demand for systems with different specifications. The model's response is then compared to the lab results using a simple practical test. For this test a supercapacitor pack with a capacitance of 50F and a maximal voltage of 56V and a battery setup with four series VRLA 12V batteries were used. The internal resistances of the supercapacitor and battery pack were measured and the battery and supercapacitor pack were connected in parallel and subjected to a single square load current. The same square load current was then applied to the model to evaluate it.

Publication year:2008

Keywords:super capacitor, ultra capacitor, battery, modeling