342
Alternative Fuels for Transportation
11.7 Fuel-Cell Vehicle Integration
The development of FCVs requires onboard integration of a FCS and electrical energy storage device with an appropriate energy management-system.
In order to evaluate the FCV with onboard PEFC, it is important to drive
test them according to a standard-duty drive cycle that includes reiterations
such as start/stop, acceleration, cruising, and braking. The integration of the
FCS into vehicles can be achieved in a manner akin to ICEVs. It has been
demonstrated that sufficiently powerful and compact drivetrains are possible to realize. Cylindrical vessels are required for hydrogen storage. The
existing vehicles lack the space for hydrogen storage for providing sufficient
drive range. The system design and integration involve a choice of fuel cell
stack sizing, operating conditions such as system pressures, temperatures,
humidification levels, subsystem components, control strategies, and a myriad of other parameters to meet the requirements; namely, low mass, restrictive packaging, fast start, fast dynamic operation, large turndown ratio;
that is, the ratio of maximum-to-minimum power, extreme environmental
conditions, freeze tolerance, long lifetime, efficiency, and cost effectiveness.
Detailed steady-state dynamic modeling and simulation tools as well as
component, subsystem, and integrated vehicle testing are desired to optimize these parameters.
11.8 Technical Issues in Fuel-Cell Vehicles
Arita (2002) highlights the technical issues of FCSs for automotive applications. Arita added that achieving the targets for automotive applications will
require technical breakthroughs in efficiency, compactness, water and thermal management, durability, and cost of PEFCs (Table 11.3).
In order to improve the total efficiency of the PEFC stacks, it is essential
to improve the efficiency of the cells constituting it. Reducing the activation
losses at the cathode is seminal for improving efficiency. One of the most
promising components in this regard is the application of a Pt-alloy catalyst. In general, the gas diffusion layer (GDL) must be optimized to reduce
the mass transfer loss, and reduction of membrane resistance is necessary
to lower the ohmic loss and contact resistance between each component.
Compactness is an important requirement for installing the FC stack in
a vehicle. It is necessary to enhance the power density of the FC stack to
achieve greater compactness. To attain high power density, the flow-field
design of the bipolar plates should be optimized to improve the performance
of the membrane electrode assembly (MEA). Another promising measure
for achieving compactness is the utilization of thinner bipolar plates. The
Alternative Fuels for Transportation
11.7 Fuel-Cell Vehicle Integration
The development of FCVs requires onboard integration of a FCS and electrical energy storage device with an appropriate energy management-system.
In order to evaluate the FCV with onboard PEFC, it is important to drive
test them according to a standard-duty drive cycle that includes reiterations
such as start/stop, acceleration, cruising, and braking. The integration of the
FCS into vehicles can be achieved in a manner akin to ICEVs. It has been
demonstrated that sufficiently powerful and compact drivetrains are possible to realize. Cylindrical vessels are required for hydrogen storage. The
existing vehicles lack the space for hydrogen storage for providing sufficient
drive range. The system design and integration involve a choice of fuel cell
stack sizing, operating conditions such as system pressures, temperatures,
humidification levels, subsystem components, control strategies, and a myriad of other parameters to meet the requirements; namely, low mass, restrictive packaging, fast start, fast dynamic operation, large turndown ratio;
that is, the ratio of maximum-to-minimum power, extreme environmental
conditions, freeze tolerance, long lifetime, efficiency, and cost effectiveness.
Detailed steady-state dynamic modeling and simulation tools as well as
component, subsystem, and integrated vehicle testing are desired to optimize these parameters.
11.8 Technical Issues in Fuel-Cell Vehicles
Arita (2002) highlights the technical issues of FCSs for automotive applications. Arita added that achieving the targets for automotive applications will
require technical breakthroughs in efficiency, compactness, water and thermal management, durability, and cost of PEFCs (Table 11.3).
In order to improve the total efficiency of the PEFC stacks, it is essential
to improve the efficiency of the cells constituting it. Reducing the activation
losses at the cathode is seminal for improving efficiency. One of the most
promising components in this regard is the application of a Pt-alloy catalyst. In general, the gas diffusion layer (GDL) must be optimized to reduce
the mass transfer loss, and reduction of membrane resistance is necessary
to lower the ohmic loss and contact resistance between each component.
Compactness is an important requirement for installing the FC stack in
a vehicle. It is necessary to enhance the power density of the FC stack to
achieve greater compactness. To attain high power density, the flow-field
design of the bipolar plates should be optimized to improve the performance
of the membrane electrode assembly (MEA). Another promising measure
for achieving compactness is the utilization of thinner bipolar plates. The