Portable micro fuel cells

Hahn, R. Krumm, M. Reichl, H. Thermal management of portable micro fuel cell stacks. Proceedings of the 19th Annual IEEE Semiconductor Thermal Measurement And Management Symposium, San Jose, CA, 11-13 March 2003 Institute of Electrical and Electronics Engineers Inc., 2003 202-209. 

R. Hahn, M. Krumm, and H. Reichl, Thermal Management of Portable Micro Fuel Cell Stacks, Proceedings of the 19 th IEEE Semiconductor Thermal Measurement and Management Symposium SEMI-THERM, San Jose, CA USA, March 11-13, pp. 2002-2009, 2003. 

ISPP imits are not the only micro device imits of interest for space applications micro fuel cells, compact cleanup units for water treatment, portable heating and cooling units and devices for chemical processing and mining are considered [91]. 

Micro-fuel cells using small tanks of hydrogen could operate mobile generators, electric bicycles and other portable items. Large 250-kW... 

The need for different and novel materials as possible DLs has increased substantially in the last few years—especially with the development of new and more complex fuel cell designs. Lurthermore, the interest in small-scale fuel cells to be used as battery replacements in portable electronic devices such as PDAs, laptops, cell phones, music players, etc. has pushed the research for irmovative, inexpensive, and efficient fuel cells further [72,73]. Therefore, it is not surprising that most of the recent new DL materials are being used in micro fuel cells. 

Because of its lower temperature and special polymer electrolyte membrane, the proton exchange membrane fuel cell (PEMFC) is well-suited for transportation, portable, and micro fuel cell applications. But the performance of these fuel cells critically depends on the materials used for the various cell components. Durability, water management, and reducing catalyst poisoning are important factors when selecting PEMFC materials. 

Technical progress as well as investments in PEMFCs for transportation, stationary, portable, and micro fuel cell applications has been dramatic in recent years. The present view is ophmistic for fuel cell power generation the status is presently at the field trial level, or early commercialization stage, moving into volume commercialization. Although commercially viable, niche PEMFC applicahons exist today, the first commercial mass markets for fuel cells are expected to be for handheld electronic devices, PCs, and other portable devices. 

Micro fuel cells intended for use, e.g., with portable electronics, will be mentioned below in section 3.6, as they are often based on direct methanol fuel. Direct methanol fuel cells are also PEM fuel cells, as they are based on the transport of hydrogen ions through a solid polymer electrolyte. 

Figure 3.55. Carbon nanohorn substrates used for catalyst backing in NEC s passive DMFC design. (From Y. Kubo (2004). Micro fuel cells for portable electronics. In Proc. 15 World Hydrogen Energy Conference, Yokohama. Used with permission.)...

Fig. 6 The molded flat array of air-breathing DMFCs, shown held between the fingers on the right, generates power in the range 0.5-1 W in a concept prototype of a DMFC system for portable consumer electronics applications. (MTI Micro Fuel Cells).

Recently we have developed spray-pulsed reactors equipped with alumi-monolith (alumite) catalyst plates for the efficient supply of hydrogen, using organic hydrides, to the micro-fuel cells of portable electrical appliances such as mobile phones, laptop computers and nurse robots, as shown in Fig. 

Most portable electronic devices would require a fuel cell of less than 100 W output, and often considerably less. Here, effort is concentrated on perfecting the DMFC, because of the convenience of methanol as a liquid fuel. Clearly, portable power is a very promising high-value opportunity for small fuel cells, but the outcome would have little impact on overall energy consumption and is not strictly part of the hydrogen energy scene. Nevertheless, many observers believe that volume production of micro fuel cells would be a key technical and economic driver for the entire fuel-cell market. 

Portable electronics applications (micro fuel cells)... 

Micro fuel cells are primarily designed for portability. Their size is dictated by the size of the device they power. Consumer products such as laptop PCs, portable electronic video games, video cameras, PDAs, and cellular telephones are several examples of portable electronics where a micro fuel cell could be used to power the device. These fuel cells have been designed on primarily two fuel cell types, DMFC and PEMFC. These fuel cell types provide high power density based on their small size and are suitable for powering small devices. A need for high efficiency, combined with a need for lightweight and small size makes these fuel cell types ideal. 

THERMAL CONSTRAINTS OF PEM MICRO FUEL CELLS FOR PORTABLE ELECTRONICS... 

Despite the fact that the primary focus of the new initiative revolved around automotive technologies, the President s Hydrogen Fuel Initiative was crafted into a balanced program that benefited a wide range of technologies and applications, including micro, portable, stationary fuel cells. 

Thermal Constraints of PEM Micro Fuel Cells for Portable Electronics... 

Eye for Fuel Cells."Fuel Cells for Portable Applications Conference Announcement." Boston September 2002 "NEC Researchers Employ Carbon Nanotubes to Design Micro DMFC for Portables." Hydrogen Fuel Cell Letter October 2001... 

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