Intermediate Temperature Fuel Cell Electric Vehicles: Simulation Study
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Mobility engineering (MPMOB), MSc
Publicerad
2023
Författare
Bhagwat, Ashwin
Kumar Tiwari, Rahul
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Low-temperature proton exchange membrane fuel cells (LT-PEMFC) operating at
60 – 80 ℃ have shown higher efficiency, and better integration with vehicle appli cations but face issues such as slow reaction rate, water flooding, and low thermal
gradient with respect to surrounding. On the other hand, high-temperature (HT)
PEMFC operating at 150 – 200 ℃ enhances overall performance due to higher gas
diffusivity, membrane conductivity, and waste heat treatment system. But due to
high operational temperature, the water content of the HT-PEMFC decreases, lead ing to higher internal resistance, resulting in reduced performance of the fuel cell.
Therefore, this study focuses on building a detailed PEMFC model which can be
operated at 80 ℃, as well as at 100, and 120 ℃ intermediate temperature (IT),
and comparing the performance, power distribution, and efficiency at LT, and IT
operation. A maximum power of 152 kW, 151 kW, and 130 kW is achieved while
operating the same FC system at 80, 100, and 120 ℃ respectively. The efficiency
results show that the FC operating at 80 ℃ has an efficiency range of 51% – 41%,
whereas, at 100, and 120 ℃, the efficiency drops to 51% – 41%, and 34% – 33%,
respectively. A single integrated system is built separately, which operates at 80 ℃
when the power demand is between 0 – 85%, and at 100 ℃ when the power demand
is higher (85 – 100%). This system design allows for a 55% reduction in radiator
size, and a 25% reduction in compressor map while maintaining system efficiency
between 40 – 51%.
The degradation effect of the FC stack when operating at 80, 100, and 120 ℃ is
also modeled. The results show that operating the fuel cell at 120 ℃ leads to accel erated degradation, and lower efficiency when compared to operating it at 80, and
100 ℃. Therefore, the FC system, which operates at a maximum of up to 100 ℃, is
integrated with the vehicle model to analyze its effect at the vehicle level. The re sults show that hydrogen consumption (kg/100km) is approximately the same when
operating at 80 ℃, and integrated system (running at 80 – 100 ℃). However, while
operating the system only at 100 ℃, consumes 25% more hydrogen for the same
driving cycle. Therefore, running the FC with an integrated system operational at
80, and 100 ℃ shows promising results.
Beskrivning
Ämne/nyckelord
IT-PEMFC, cell calibration, BoP modeling, degradation modeling, sys tem performance .