Variable power control in liquid fuel cells

Highlights

The National Research Council, in cooperation with the University of British Columbia, has developed a fuel cell with an adjustable barrier means for modulating power output. The barrier means can selectively expose or cover the electrolytic, active region of the fuel cell in response to power demands.

This mechanism is contained within the fuel cell, and may simplify or even dispense with the need for some currently available methods applied to control the power output of active fuel cells. It also provides a power control mechanism for passive fuel cells, which was not previously available. In short, the technology offered provides a simple system and method for operating a fuel cell under variable load conditions.

Technology transfer

The implementation of this technology can be combined with a variety of fuel cell designs, including a membraneless fuel cell architecture, as available with reference to NRC ID: 12170. Apart from general consumer applications, this integrated technology offers opportunities for the military and aerospace sectors, such as the possibility to design highly-portable, stand-alone power systems.

Market applications

This opportunity is well-suited for an array of liquid fuel cell system applications and niche applications requiring individually portable power systems.

How it works

The National Research Council, in cooperation with the University of British Columbia, has developed a method of modulating a fuel cell's power output.

The advancement of portable electronics and the continual integration of functionality into a single all-encompassing device has created an increased demand on energy supply. The incumbent Li-ion battery is not projected to sufficiently accommodate this growing demand. As a result, for devices operating in the <100 W range, the direct methanol fuel cell (DMFC) has emerged as an attractive alternative. The DMFC can be operated under a passive or active configuration and the target application largely determines which configuration is used.

Fuel cells are typically designed for optimal power output under specific conditions, and when these conditions are changed, the fuel cell must then operate under sub-optimal conditions. Efforts to address this issue with active fuel cells have generally focused on the "balance of plant" (BOP) aspects of the fuel cell system, in which the power output can be altered by controlling the concentration of the methanol fuel using a system of sensors, pumps and valves to compensate for the variable power demands of the device being powered. This not only leads to increases in system complexity and cost, but also to the fuel cell operating under suboptimal conditions, frequently resulting in reduced efficiency, performance and durability.

For passive fuel cell systems, the issue is more critical because they do not contain additional BOP components to control the fuel concentration or stoichiometry at different power levels.

The technology offered provides a simple system and method for operating a fuel cell under variable load conditions. The approach involves the application of an adjustable, movable barrier that can selectively cover or uncover portions of the electrolytic, active area of the fuel cell to reduce or increase power output. With this mechanism, the signs of fuel cell failure or performance degradation can also be detected and compensated for, by selectively testing and adjusting the open, reactive region of the fuel cell.

Benefits

  • simple system and method for operating a fuel cell under variable load conditions
  • provides power solution for passive fuel cells where such control means were previously unavailable
  • provides solution for smaller, portable devices to optimize power outputs and efficient fuel cell use

Patents

  • NRC file 12170: Patents pending in the United States and Canada.

Contact

To inquire about this technology, please contact:

Dann Chow, Portfolio Business Advisor
Telephone: 604-221-3157
Email: Dann.Chow@nrc-cnrc.gc.ca

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