**5. Conclusions**

The model at hand represents a one-dimensional, dynamic proton exchange membrane fuel cell. To estimate the cell voltage, activation, ohmic and concentration overpotentials are calculated and subtracted from the ideal cell voltage in every time step. Furthermore, the water transport through the membrane by means of osmosis, diffusion and hydraulic permeation is considered. In order to reduce the complexity and computational load, simplified correlations are used to estimate the cell performance. This approach allows the model to be used in complex systems such as complete vehicle models or real-time applications. Two modes of operation allow for flexible use of the fuel cell model by supplying either polarization tables or physical cell parameters, which enables a quick model setup. The program code is written in MATLAB and designed to be used in a MATLAB-function-block inside of a Simulink model. By compiling the Simulink model as C/C++, this PEMFC model can also be used within any software tool that supports Simulink coupling. It is supplied under an open-access license to make it available to anyone for free.

However, the use of simplified equations for cell performance estimation also reduces the accuracy of the results. In particular, the consideration of the MEA can be further expanded because water and gas transport as well as concentration, can be significantly affected by the MEA composition. Additionally, cell geometry and local differences in the distribution of temperature, current density and reactants can also affect the overall performance. For future expansions, the computational load should be considered, in order to not increase the model's calculation time too much.

**Supplementary Materials:** The supplementary materials are available online at http://www.mdpi.com/1996-1073/ 12/18/3478/s1.

**Author Contributions:** Formal analysis, investigation, methodology, software, and visualization, writing—original draft, A.L.L.; data curation, S.C.K.; supervision, resources, H.R.; validation, A.L.L. and S.C.K.; writing—review and editing, S.C.K. and H.R.; conceptualization, project administration, A.L.L., S.C.K. and H.R.

**Funding:** This research received no external funding.

**Conflicts of Interest:** The authors declare no conflict of interest.
