Can the PEM Fuel Cell Simscape model be scaled down to 100 W?

Adapting the MathWorks PEM Fuel Cell System (Simscape-based) to a low-power application, specifically a 100 W PEMFC stack.

I would like to know if anyone has successfully scaled down this model for such low power, and if so, what specific parameters or subsystems need the most attention (e.g., MEA parameters, flow channel sizing, or thermal management).

Any shared experiences, parameter tuning advice, or model references would be very helpful in guiding my adaptation process.

Answer 1

[Yifeng Tang]

I can share a case study where the original model is scaled UP by 4 times, to around 400kW. Maybe you can repeat the workflow for your application.

In "PEMFuelCellSystemStep1.slx", the goal is to properly scale up the stack model. This includes

1. Use a simplified "cooling system", assign a temperature, so I don't need to design/scale a cooling system just yet.
2. Use VERY large volume as Anode and Cathode, to simulate constant boundary condition for the MEA. Mimic the typical condition in the MEA in the volumes. Enable S port for H2 & O2 removal. Trial and error to get the yH2 & yO2 right.
3. Now we have a test harness, scale up MEA to get more power. increase area, or increase number of cells.

In "PEMFuelCellSystemStep2.slx", the goal is to properly scale up anode side. With 4x size of the whole system, we now need 4x H2 flow, which requires us to scale up all diameter by 2, area by 4, volume by 4, etc.

In "PEMFuelCellSystemStep3.slx", the goal is to properly scale up cathode side. With 4x size of the whole system, we now need 4x H2 flow, which requires us to scale up all diameter by 2, area by 4, volume by 4, etc. The compressor map also needs to be adjusted to produce 4x mass flow.

In "PEMFuelCellSystemStep4.slx", the goal is to properly scale up the thermal management. It now needs to provide 4x cooling capacity. This includes scaling up the pipe diameters, length, heat transfer area, port area, pump max flow, etc.

Finally, in "PEMFuelCellSystemScale400kW.slx", the electrical load is scaled up by 4 times and the full model is tested with the pre-defined load profiles.

You may follow the steps, and think what physically needs to be changed and try to get those reflected in the model/block parameters.

Hope this helps.

[Ahmad]

Dear @Yifeng Tang

Thank you for sharing the model.

When I try to run PEMFuelCellSystemStep1,2,3,4.slx, I get the following error:

Warning: The Simscape component 'FuelCell' in 'Membrane Electrode Assembly' is invalid.

Caused by: 'foundation.enum.moisture_source_spec.vapor' is not defined in this scope.

Could you please advise how to resolve this?

Is there a specific Simscape version required, or should I modify the custom component file to import the enum manually?

Appreciate your guidance.

[Ahmad]

I was able to resolve the issue by replacing the original FuelCell.ssc file from the MATLAB PEM fuel cell example with the custom upscaling version provided in the model folder.

This updated FuelCell component includes the correct parameter definitions and enum references (e.g., moisture_source_spec.vapor), which allowed ssc_build to compile successfully and the simulation to run without errors.

The updated component seems to be designed specifically for the 400 kW stack and is fully compatible with the upscaled system structure.

[Yifeng Tang]

Nice!

The steps you've taken are exactly what I would suggest. The FuelCell.ssc is a direct copy from the shipping example. I was using R2023b when I made the example a while ago. The FuelCell.ssc file in later versions has been updated with newer internal Simscape function/component names.

Again, hope you find this helpful.

[Ahmad]

Dear @Yifeng Tang,

I hope you're doing well. I wanted to share an issue I encountered while working through Step 2 of the PEMFC downscaling process.

I’d like to clarify:

1. Should parameter updates be made via the Model Explorer > Model Workspace )? I'm not sure whether the gas channel geometry values are defined in the workspace or embedded in each block — if they are included in the C structure, I’d appreciate your confirmation.
2. Or should all updates be made directly in the block parameter dialog of each component?

Thank you very much for your support so far. I’ll be happy to keep you updated as I continue through the next steps.

Best regards,

[Yifeng Tang]

I suggest that you change the values in the script where the parameters are define, then "reinitialize".