LONDON — General Motors' latest fuel cell stack sets a new world standard for power density that packs 60 percent more power than any competitor, GM announced at a technical conference here today.
The new GM stack generates 1.75 kilowatts (kW) per liter, setting an industry benchmark for volumetric efficiency — the measurement of the stack's power output in kilowatts vs. its volume.
The highest power density announced by any other fuel cell manufacturer to date is 1.1 kW per liter by Ballard Power Systems, according to GM scientists.
"Reducing the size and weight of the fuel cell stack while maintaining or improving its power output is important for packaging, design and affordability," said Matthew Fronk, chief engineer of fuel cell systems for GM's Global Alternative Propulsion Center (GAPC).
Smaller stacks create more space for other components and allow their use in smaller vehicles and stationary units. They require less material, providing an opportunity for further cost savings. Stack volume can be tailored to the power needs of the vehicle in which it is installed.
"We achieved this efficiency through further developments in materials, and improving how we form parts of the fuel cell and how the stack is put together," said Gary Stottler, director of stack development at GAPC.
The new stack has 640 cells with a continuous power output of 102kW (134 horsepower) and a peak power output of 129kW (173 hp). It weighs 82 kg (180 pounds) and measures 32 1/4 inches by 5 1/2 inches by 20 inches, or 82 cm by 14 cm by 50 cm (58 liters).