Why are heat pipes not used in PEM fuel cells?

[Topher925]

Just curious as to why you don't find heat pipes or any passive cooling in larger PEM type fuel cells. I have seen them used in methanol fuel cells but not FCs for hydrogen. Is there a good reason for this? Is it because the power density of fuel cells is typically higher than that in many others or is because the technology just hasn't really been explored? Any input would be greatly appreciated as I really need a solid answer for this question.

 

[Topher925]

Anyone?

 

[makethings]

I am curious to know the answer to this.

Are you sure there are no embedded water/air cooling plates between each fuel cell?

I can only take a stab at this problem by saying if the PEM fuel cell is operating at high current densities, it is going to produce a lot of water. Perhaps the excess heat is being used to evaporate the H20 at the cathode to prevent back diffusion. But then again, they have to keep the electrolyte membrane hydrated so they have to remove the heat or they're putting in more water as its input.

 

[Topher925]

I am curious to know the answer to this.

Are you sure there are no embedded water/air cooling plates between each fuel cell?

I can only take a stab at this problem by saying if the PEM fuel cell is operating at high current densities, it is going to produce a lot of water. Perhaps the excess heat is being used to evaporate the H20 at the cathode to prevent back diffusion. But then again, they have to keep the electrolyte membrane hydrated so they have to remove the heat or they're putting in more water as its input.

Cooling systems are used in almost all fuel cells. For medium to large cells this usually consists of channels integrated into the bipolar plates of each FC in the FC stack. Water or some heat carrying fluid is then pumped through those channels in order to regulate heat and temperature. Heat pipes however do not operate on this principle. Heat pipes are passive devices that work by phase change of a the working fluid sealed in the heat tube. Not only are heat pipes passive but they have an extremely high heat flux compared to other methods of thermal management. I've found a lot of patents for heat pipes in PEMFCs and a couple papers for methanol fuel cells but nothing for larger hydrogen PEMFCs.