Small Fuel Cells for Portable Devices

Early in the 1990s, a variety of new portable devices become mass consumer goods notebook-type computers, videocameras, digital cameras, cellular phones, camcorders, audio and video players, medical appliances for individual use, and others. Various storage batteries were used as their power supply nickel-cadmium and nickel-hydride at first, and later, lithium-ion batteries. Such batteries sustain their electronic devices for no longer than several hours, and when empty, require many hours of recharging, which detracts considerably from the convenience offered by the devices. 

It was in this context that attention turned to the development of new types of small fuel cells and to small power plants assembled from such fuel cells. The introduction of small power plants to domestic technical applications opened ways for a broad conunercialization of fuel cells, and with it a flow of new sources of financing that would support further fuel cell development. 

Apart from domestic applications, a need for new, improved power sources of small size also arose in different portable devices to be used in the military sector, such as night-vision devices and individual communication equipment. 

Fuel Cells Problems and Solutions, Second Edition. Vladimir S. Bagotsky. 

Kjeang et al. wrote in 2009 With the exception of a lunited number of stationary units, large-scale fuel cell heat and power plants have not yet gone beyond the field of trial stage (small-scale commercialization). Small fuel cells for portable electronic equipment are considered rather close to market for a number of reasons. It is unlikely that technical development of batteries will keep pace with the accelerating power demand for portable electronic devices. The market for portable electronics has an inherently high cost tolerance.  

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The first edition of this book was published in December 2008. This second edition is updated with information published after this date up to October 2011. Two chapters of the first edition were rewritten Chapter 15 (modeling of fuel cells) and Chapter 14—now Chapter 17 (small fuel cells for portable devices). In this edition three new chapters of high current interest are also included Chapter 14 (structural and wetting properties of fuel cell components). Chapter 16 (experimental methods for fuel cell stacks), and Chapter 18 (nonconventional design principles for fuel cells). 

In previous sections it was shown that for technical and economic reasons the number of high-power stationary power units based on fuel cells is relatively limited tens for large units and hundreds (up to thousands) for smaller ones. At the same time, there are very large market demands (hundred of thousands) for low-power and small power units for portable devices. During future decades a considerable increase in market demand for medium-power units for electric vehicles and other mobile applications (e.g., mobile fuel cells) can be anticipated. 

Shipments of fuel cell-equipped mobile devices could grow very rapidly if they can eliminate the need for frequent recharging of current battery-powered models. The Medis 24/7 Power Pack in April 2007. It is a portable, disposable power source for small electronic devices such as cell phones and MP3 players. Manufactured by Medis Technologies, it is based on Direct Liquid Fuel cell technology, and may be of particular utility in military applications. Elsewhere, MTI MicroFuel Cells manufactures a power pack for portable electronics that is based on direct methanol fuel cell technology that it calls Mobion. 

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. 

There have recently been some indications, particularly from Japan, that portable fuel cells for use in laptop computers, cell phones, and other small devices may appear on the market in the near future. However, even if such fuel cells become available, the area does not appear to offer many employment opportunities for Texas community and technical college graduates. Since these fuel cells will imdoubtedly be discarded after use, there will be no jobs related to their installation, maintenance, or operation, and it does not appear that any manufacturing facilities wiU be located in Texas. 

Portable electronic devices need very low power for their operation, often milliwatts or at most a few watts, and no more than 10 W. Small low-power fuel cells designed as a power supply for portable devices are termed micro-fuel cells or mini-fuel cells (mini-FCs), the latter term being preferred. The concept of a miniamrization of fuel cells is also current. 

The importance of solving these problems increased during the last decade with the rising necessity to develop small fuel cell plants for portable devices and for electric vehicles, for which a reliable simplified and low-cost design is necessary (see Chapter 17). To circumvent these problems, numerous efforts have been made to use other, nonconventional principles in fuel ceU design. 

Fuel cells were not included in the 2nd Edition of this Handbook as the technical scope and applications at that time differed from that of the battery. Now that small to medium size fuel cells may become competitive with batteries for portable electronic and other applications, these portable devices are covered in Chap. 42. Information on the larger fuel cells for electric vehicles, utility power, etc can be obtained from the references listed in Appendix F Bibliography. ... 

Abstract Polymer electrolytes are electrolytic materials that offer many advantages in the area of large, high energy density batteries for electric propulsion and in fuel cells for electric vehicle or stationary applications. At the other end of the spectrnm, polymer electrolytes are of interest for small, portable electronic devices where the battery represents a significant proportion of the device s size and weight. This chapter focuses on relevant structural, physical and electrical properties of these materials and on the related sectors where there has been considerable industrial input. 

Interestingly, the PEMFC may also operate directly on methanol. Naturally, the problems associated with high coverage of various intermediates will be present, as mentioned above, as well as additional problems such as loss of methanol over the membrane. Nevertheless, it is possible to operate a methanol fuel cell with a voltage around 0.4 V and a reasonable current, to power small mobile devices such as portable computers and cell phones and make them independent of connection to the conventional power net. For more details on fuel cells we refer the reader to L. Carr-ette, K.A. Friedrich and U. Stimming, Fuel Cells 1(1) (2001) 5-39. 

Portable fuel-cell systems are systems that produce electricity for devices with a performance ranging from several watts to 10 kilowatts. The heat produced in the process is a by-product that is normally not used. The system has, therefore, to be cooled down by fans or cooling surfaces, etc. A wide range of applications is possible for fuel cells from small electronic devices like camcorders, mobile phones, laptops, etc. to electric tools, back-up systems, or power generation on boats or caravans. 

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. 

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