Fuel-cell truck study finds major energy and thermal losses

What the study found: The study found that a fuel cell hybrid electric heavy-duty truck had substantial energy losses across its powertrain and thermal management systems. The fuel cell stack converted energy at 47.98% efficiency, but only 38.99% of the initial energy reached the wheels after losses in power electronics, transmission, and auxiliary systems.
Why the authors say this matters: The authors conclude that their energy flow analysis framework can quantify energy use, component efficiency, and thermal behavior in fuel cell hybrid heavy-duty trucks. They say the work provides a reference for improving performance and engineering application of these trucks.
What the researchers tested: The researchers experimentally examined a fuel cell hybrid electric heavy-duty truck under user-defined driving cycles. They analyzed energy consumption distribution, efficiency metrics of key powertrain components, and thermal management system performance.
What worked and what didn't: The power battery helped balance loads, but energy recovery during deceleration was only 26.1%. Motor efficiency fell below 85% during medium-speed and low-torque operation in intermediate gears, suggesting optimization potential for recovery and shift strategies. Thermal management was partly effective, but the study reports battery, motor, cabin, and coolant temperature issues, along with compressor instability.
What to keep in mind: The abstract describes limitations in handling heat load at the battery end and notes the need to improve cooling design by increasing cooling capacity or optimizing algorithms. It also does not provide details on the driving cycles beyond stating that they were user-defined, and it does not describe limitations beyond those reported in the thermal and efficiency results.

Key points

• The fuel cell stack achieved 47.98% conversion efficiency.
• Only 38.99% of the initial energy reached the wheels after system losses.
• Energy recovery during deceleration was 26.1%.
• Motor efficiency fell below 85% during medium-speed, low-torque operation in intermediate gears.
• The battery cell temperature rose to 35 °C, while the motor temperature increased from 27 °C to 50 °C before stabilizing at 45–50 °C.