Direct methanol fuel cells integrated with fuel reservoirs have been proposed as power sources in applications that involve power demands up to about 50 W. A prior concept of direct methanol fuel cells as alternatives to re- chargeable batteries in such applications was reported previously in “Miniature Fuel Cells for Small, Portable Electronic Devices” (NPO-21066), NASA Tech Briefs, Vol. 26, No. 8 (August 2002), page 30. The prior concept called for the fuel (a methanol/water solution) to be supplied from reservoirs outside the fuel cells. The present concept would eliminate the need for separate reservoirs, thereby reducing bulk and complexity and increasing convenience of use.
A fuel-cell assembly according to the present proposal would include a stack of fuel cells either above or surrounded by a fuel reservoir, all contained within a single housing. Wicks would protrude from the anodes in the stack into the reservoir. The wicks would deliver the methanol/water fuel solution to the anodes by capillary action. Oxygen in the air would be accessible to the cathodes.
The water produced in the fuel-cell chemical reactions could be discharged as a liquid into the reservoir to maintain the required relative concentrations of water and methanol; alternatively, this water could be emitted as a gas along with carbon dioxide, which is also produced in the fuel-cell chemical reactions. Refueling could be accomplished by injecting or pouring additional methanol or methanol/water solution into the reservoir from a syringe, a container similar to a cigarette-lighter-fuel container, or other suitable vessel.
This work was done by Gerald Halpert, Harvey Frank, and Sekharipuram Narayanan of Caltech for NASA’s Jet Propulsion Laboratory.
In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to
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Refer to NPO-30331, volume and number of this NASA Tech Briefs issue, and the page number.
This Brief includes a Technical Support Package (TSP).
Direct Methanol Fuel Cells for Low-Power Applications
(reference NPO-30331) is currently available for download from the TSP library.
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Overview
The document outlines a technical support package from NASA's Jet Propulsion Laboratory (JPL) regarding Direct Methanol Fuel Cells (DMFC) designed for low-power applications. The work, conducted by Gerald Halpert, Harvey Frank, and Sekharipuram Narayanan, addresses the need for compact and efficient energy sources suitable for military personnel and consumer electronics, such as video cameras and computers.
The primary motivation behind this innovation is the recognition that existing fuel cell systems are often too large and complex for small-scale applications. The proposed DMFC system aims to eliminate the need for separate fuel reservoirs, thereby reducing bulk and complexity while increasing user convenience. The design features a stack of fuel cells integrated with a refillable reservoir, all contained within a single housing. This integration allows for the use of capillary action to deliver a methanol/water fuel solution to the anodes, eliminating the need for pumps or external storage devices.
A key aspect of the system is its ability to recycle water produced during the fuel cell reactions. This water can either be discharged into the reservoir to maintain the necessary concentration of the methanol solution or emitted as a gas along with carbon dioxide. Refueling can be accomplished easily by injecting or pouring additional methanol or methanol/water solution into the reservoir from various containers, enhancing the system's practicality for users.
The document emphasizes the novelty of this approach, highlighting its potential to provide a reliable power source without the downtime associated with traditional battery replacements or wall charging. The DMFC system is designed to deliver up to 50 watts of power, making it suitable for a range of low-power applications.
Overall, this technical support package presents a significant advancement in fuel cell technology, showcasing a solution that combines efficiency, convenience, and compactness. The work is protected under U.S. patent law, and inquiries regarding commercial use are directed to JPL's Intellectual Assets Office. The document serves as a comprehensive overview of the development and potential applications of the Direct Methanol Fuel Cell system, reflecting JPL's commitment to innovation in energy solutions.
