The settling behavior of the carbon based gas diffusion layer in PEM fuel cells
Typ
Program
Kemiteknik 180 hp (högskoleingenjör)
Publicerad
2023
Författare
Pirttimäki, Ella
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
This thesis investigate how the Gas diffusion layer in Proton Exchange Membrane
Fuel Cells settle when exposed to mechanical compression with cyclic load of 4.5 MPa
and 7 MPa. A Zwick Roell material tester was used to carry out the mechanical
testing. 3 different state of the art gas diffusion layers was examined, they are
referred to as GDL "A", "B" and "C" in this report. Three different tests were
carried out, the first with 10 cycle loading, with the load hold time of 60 s. The
second test was a 10 cycle loading test as well, but with the load hold time of 60 min.
The third test was a 50 cycle loading, with 60 s hold. Images in a Sweeping Electron
Microscope was also taken, to evaluate the fiber structure in the GDLs. The initial
reason was to evaluate the fiber structure before and after compression, this method
was abandoned, but the images still presented us with some valuable information
about the different structures of the GDLs and could be used to discuss the results.
The results imply that the load hold time effects the settling, and also confirms
previous research about the so called hysteresis effect where the first loading cycle
is the most damaging to the GDL structure. Further on, the 50 cycle testing show
that the settling of the GDLs continues after 10 cycles and more load testing, both
cyclic and static, is of interest in future research.
Beskrivning
Ämne/nyckelord
PEM fuel cells , gas diffusion layer , cyclic compression , cyclic load , mechanical load , settling behaviour , scanning electron microscope