When it comes to using hydrogen fuel cells in electric vehicles, there are two main approaches:
- Hydrogen fuel cells to directly power the electric motor(s) for propulsion: In this approach, the hydrogen fuel cell system generates electricity that directly powers the electric motor(s) responsible for propelling the vehicle. The fuel cell acts as the primary energy source, and the energy is consumed as it is generated.
Advantages:
Simpler system design without the need for a large battery pack
Potentially higher energy efficiency as energy conversion losses are minimized
Consistent power output as long as hydrogen is available
Disadvantages:
Limited power availability for acceleration or high-power demands
Lack of energy buffer or regenerative braking capability
- Hydrogen fuel cells to charge a battery pack that powers the electric motor(s): In this approach, the hydrogen fuel cell system is primarily used to charge a high-capacity battery pack. The battery pack then provides the energy to power the electric motor(s) for propulsion.
Advantages:
Energy buffer from the battery pack allows for high power demands (e.g., acceleration)
Regenerative braking capability to recover energy and extend range
Potential for smaller and more efficient fuel cell system
Flexibility in energy management and power delivery
Disadvantages:
Additional weight and cost of the battery pack
Energy conversion losses in charging/discharging the battery
Complexity in managing the two energy sources (fuel cell and battery)
Generally, using hydrogen fuel cells to charge a battery pack is considered the better approach for most passenger electric vehicles. This configuration offers more flexibility, better performance, and the ability to capture regenerative braking energy.
However, for larger vehicles like buses or trucks, where simplicity and consistent power output are more important, directly powering the electric motor(s) with the fuel cell system may be a more suitable option.
Ultimately, the choice depends on the specific vehicle requirements, performance targets, and the trade-offs between system complexity, efficiency, and cost.