Hybrid Fuel Cell/Supercapacitors stack – SUPERCAPAC

The main original aspect of the project lies in the innovative and patented stack architecture that will be used to connect directly in parallel each PEMFC cell to a single supercapacitor. Since the cell voltage always remains under 1.2 Volt, this allows using safe and cheap aqueous electrolyte capacitors, which are also much more stable and reliable than the more usual organic electrolytes at the normal operating temperature (50°C - 80°C) of PEMFC.
In a first step, a hybrid stack using standard (cylindrical) capacitors connected to the cells thanks to external terminals will be designed, built, and tested. In the meantime, flat supercapacitors meant to be inserted in a second stack between two adjacent cells will be developed. This second stack will be built and tested during the second half of the project.
The hybridization will improve the performances of the fuel cell in terms of power density and those of the capacitors in terms of energy density and will thus enlarge their operating and application range. SUPERCAPAC also intend to improve the durability and reliability of fuel cells since the supercapacitors will help limiting the voltage variations to which they are submitted, as well as the reverse currents and local degradations induced by start-up and shut-down cycles.
A close attention will be paid to the fabrication costs, robustness, and simplicity of the hybrid stacks through the careful choice of components, materials and assembling technologies. The hybridization should also allow using less or smaller auxiliaries (DC/DC converter, humidifier, cooling system).

The hybridization will improve the performances of the fuel cell in terms of power density and those of the capacitors in terms of energy density and will thus enlarge their operating and application range. SUPERCAPAC also intend to improve the durability and reliability of fuel cells since the supercapacitors will help limiting the voltage variations to which they are submitted, as well as the reverse currents and local degradations induced by start-up and shut-down cycles.

Such hybrid electricity generators with power ranging from a few tenths of Watt to a few kW could suit a wide variety of -stationary or mobile- nomad applications, such as:
• Silent and non-polluting stationary generators.
• Battery charging systems.
• Low weight and low heat signature portable power sources for the foot soldier.
• Auxiliary power units for various kinds of vehicles.
• Power sources for light aerial, underwater or ground unmanned vehicles.

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SUPERCAPAC is a multidisciplinary project gathering laboratories in the fields of material sciences, (IMN – Institut Jean Rouxel), electrical engineering (GREEN) and mechanical engineering (LEMTA). Its main topic is the direct hybridization of a Polymer Electrolyte Membrane Fuel Cells (PEMFC) with supercapacitors, with the objective to reach a high level of integration by inserting the supercapacitors within the fuel cell stack.

Such hybrid electricity generators with power ranging from a few tenths of watts to a few kW could suit a wide variety of -stationary or mobile- nomad applications, such as:
• Silent and non-polluting stationary generators.
• Battery charging systems.
• Low weight and low heat signature portable power sources for the foot soldier.
• Auxiliary power units for various kinds of vehicles.
• Power sources for light aerial, underwater or ground unmanned vehicles.

The main original aspect of the project lies in the innovative and patented stack architecture that will be used to connect directly in parallel each PEMFC cell to a single supercapacitor. Since the cell voltage always remains under 1.2 V, this allows using safe and cheap aqueous electrolyte capacitors, which are also much more stable and reliable than the more usual organic electrolytes at the normal operating temperature (50°C - 80°C) of PEMFC.

In a first step, a hybrid stack using standard (cylindrical) capacitors connected to the cells thanks to external terminals will be designed, built, and tested. In the meantime, flat supercapacitors meant to be inserted in a second stack between two adjacent cells will be developed. This second stack will be built and tested during the second half of the project.

The hybridization will improve the performances of the fuel cell in terms of power density and those of the capacitors in terms of energy density and will thus enlarge their operating and application range. SUPERCAPAC also intend to improve the durability and reliability of fuel cells since the supercapacitors will help limiting the voltage variations to which they are submitted, as well as the reverse currents and local degradations induced by start-up and shut-down cycles.

A close attention will be paid to the fabrication costs, robustness, and simplicity of the hybrid stacks through the careful choice of components, materials and assembling technologies. The hybridization should also allow using less or smaller auxiliaries (DC/DC converter, humidifier, cooling system).