Direct Methanol Fuel Cells for Increased Energy Capacity in Laptops and Other Mobile Electronics

Reduces Bulk and Increases Operational Efficiency of DMFCs for Use in Portable Devices

These direct methanol fuel cells can increase the capacity of energy storage in portable electronics, such as laptops and tablets. Methanol is an inexpensive, widely available fuel that can be extracted from both natural gas and renewable plant materials, such as wood. Though long-lasting, existing direct methanol fuel cells (DMFCs) are the size of a briefcase and require bulky fans, exit condensers, and other water management components to function properly.

Researchers at the University of Florida have developed fuel cells that contain microscale passages, eliminating any need for large water management components while supporting operation at high ambient temperature. These DMFCs are two to three times smaller than available batteries capable of 24-hour operation and facilitate low-cost monitoring of methanol concentration.

Application

Direct methanol fuel cells (DMFCs) that are small enough to replace rechargeable batteries in consumer electronics and other mobile devices

Advantages

• Maintains water balance during fuel cell operation, dramatically increasing operational efficiency by negating the need for traditional water recapturing techniques
• Monitors fuel concentration without using sensors, cutting costs
• Eliminates physical space otherwise occupied by water recapture components and fuel sensors, reducing device bulkiness
• Suits long-duration applications requiring both low weight/volume and moderate/average power, improving devices such as gaming laptops or small UAVs

Technology

Direct methanol fuel cells (DMFCs) continuously require water to react with the methanol fuel at the anode side of the cell; it is generally obtained from the water produced on the cathode side. Available DMFCs utilize a bulky system of fans, exit condensers, and other components to recapture evaporated water from the exiting cathode air stream. This DMFC features an innovative structure that forces water to flow directly from the cathode into the anode stream. Microscale passages within the DMFC reroute water and effectively prevent water losses to the air, all while using much less space. It achieves optimal water balance during fuel cell operation through innovative algorithms that adjust fuel and oxidizer injection rates in response to power load demands. As a result, no excess water is generated. The system also provides inexpensive fuel concentration measurement. Using a computer algorithm, it eliminates the need for expensive in-place fuel sensors and collects information about temperature, fuel-level, stack currents, fan speed, and fuel-injection pump output rates.