Stackable Miniature Fuel Cells With On Demand Fuel And Oxygen Supply

This dissertation summarizes our progress towards miniature fuel cells that could replace and outperform small batteries to meet various power demands. With increasing need of power being critical for portable electronics, the demand for better batteries continues to grow. Lithium-ion batteries dominate the market at the moment, but the current capacities on the order of 200 Wh/kg are approaching their inherent limits. Many researchers have being pursuing alternative power sources, forming a rapidly growing field in engineering and science. For applications too small for batteries (below 1 cm and even 1 mm), currently no proper power source is available, despite over a decade of significant efforts by many in power micro electromechanical systems (power MEMS). Encouraged by the advantages of their macro counterparts, micro fuel cells have received attention as a potentially powerful, efficient, and clean power source for miniature applications, resulting in extensive research in micro fuel cells and even commercial introduction of some small fuel cells. However, they are not yet powerful enough to consider someday replacing batteries for a wide range of portable applications. While the promise of fuel cells is in their high theoretical energy density, unfortunately the promise is lost in current portable fuel cells because of their complex system that includes ancillary components such as mechanical pump, reformer, pressurized oxygen source, and gas separator. This dissertation summarizes our attempt to realize a full (i.e., complete, standalone) fuel cell with small footprint, extending the spirit of self-pumped fuel that eliminated ancillary components in the active fuel circulation system to self-controlled oxygen generation for a packaged oxidant supply. We first eliminate fuel pump, gas separator, membrane electrode assembly (MEA) and even pressurized oxygen tank to make anodic chamber simple and self-regulating. As the next step towards realizing a full fuel cell stackable as batteries, we develop a self-regulating oxygen generation system that supplies oxygen within the fuel cell, i.e., not relying on the ambient air. For our final goal, we integrate the self-pumped fuel supply and the self-regulated oxygen supply into one device to prove the concept of a full fuel cell suitable for a stacked configuration.

This volume contains an archival record of the NATO Advanced Institute on Mini – Micro Fuel Cells – Fundamental and Applications held in Çesme – Izmir, Turkey, July 22–August 3, 2007. The ASIs are intended to be a high-level teaching activity in scientific and technical areas of current concern. In this volume, the reader may find interesting chapters on Mini- Micro Fuel Cells with fundamentals and applications. In recent years, fu- cell development, modeling and performance analysis has received much attention due to their potential for distributed power which is a critical issue for energy security and the environmental protection. Small fuel cells for portable applications are important for the security. The portable devices (many electronic and wireless) operated by fuel cells for providing all-day power, are very valuable for the security, for defense and in the war against terrorism. Many companies in NATO and non-NATO countries have concentrated to promote the fuel cell industry. Many universities with industrial partners committed to the idea of working together to develop fuel cells. As tech- logy advanced in the 1980s and beyond, many government organizations joined in spending money on fuel-cell research. In recent years, interest in using fuel cells to power portable electronic devices and other small equipment (cell phones, mobile phones, lab-tops, they are used as micro power source in biological applications) has increased partly due to the promise of fuel cells having higher energy density.

Today's consumers of portable electronics consumers are demanding devices not only deliver more power but also work healthy for the environment. This fact alone has lead major corporations like Intel, BIC, Duracell and Microsoft to believe that Microfuel Cells could be the next-generation power source for electronic products. Compact and readable, Microfuels Principles and Applications, offers engineers and product designers a reference unsurpassed by any other in the market. The book starts with a clear and rigorous exposition of the fundamentals engineering principles governing energy conversion for small electronic devices, followed by self-contained chapters concerning applications. The authors provide original points of view on all types of commercially available micro fuel cells types, including micro proton exchange membrane fuel cells, micro direct methanol fuel cells, micro solid oxide fuel cells and micro bio-fuel cells. The book also contains a detailed introduction to the fabrication of the components and the assembly of the system, making it a valuable reference both in terms of its application to product design and understanding micro engineering principles. An overview of the micro fuel cell systems and applications A detailed introduction to the fabrication of the components and the assembly of the system Original points of view on prospects of micro fuel cells

Explains the basics of how fuel cells work and how they might be useful for the U.S. Department of Agriculture, Forest Service at remote facilities and in other situations that require a clean, quiet alternative supply of electrical power.

FUEL YOUR EVIL URGES WHILE YOU BUILD GREEN ENERGY PROJECTS! Go green as you amass power! Fuel Cell Projects for the Evil Genius broadens your knowledge of this important, rapidly developing technology and shows you how to build practical, environmentally conscious projects using the three most popular and widely accessible fuel cells! In Fuel Cell Projects for the Evil Genius, high-tech guru Gavin Harper gives you everything you need to conduct practical experiments and build energizing fuel cell projects. You'll find complete, easy-to-follow plans that feature clear diagrams and schematics, as well as: Instructions for fascinating sustainable energy projects, complete with 180 how-to illustrations Explanations of how fuel cells work and why the hydrogen economy will impact our lives in the near future Frustration-factor removal-all the needed parts are listed, along with sources Science fair project ideas that are on the cutting edge of the latest technological developments Fuel Cell Projects for the Evil Genius gives you complete plans, instructions, parts lists, and sources to: Understand how hydrogen could meet our energy needs in a post-carbon economy Build a fuel cell car to race against your friends Build an intelligent fuel cell car which autonomously drives Build a simple fuel cell using adhesive bandages Hydrogen fuel your iPod Have a hydrogen barbecue-cook your food with zero carbon emissions! Discover how the amounts of hydrogen supplied to fuel cells affect the amounts of electricity produced And much more!

(Cont.) Microfabrication techniques such as photolithography, sputtering, and photo-resist liftoff were used to create various micro SC-SOFC that are 25-400microns long and 15-40microns wide, utilizing platinum and gold for the electrodes and YSZ as the electrolyte. After successfully fabricating these micro SC-SOFCs, the fuel cells were tested in a microprobestation with a custom gas chamber enclosure, which was exposed to CH4:02:N2 at 20:20:100 ccm or 40:20:100 ccm. A switch in the OCV from a negative voltage to a positive voltage was observed around 600°C, possible indicating change in electrochemical reactions with temperature. An OCV of [approx.] 0.4V and peak power density of 27[mu]W/cm2 at 900°C in a 1:1 methane:oxygen ratio was achieved. A stack of 10 micro SC-SOFCs as fabricated showing a cumulative OCV of 3.3 V, of an average 0.33 V per cell at 600°C in a 2:1 methane:oxygen ratio. Ongoing research will involve characterizing micro SC-SOFCs to understand the fundamental reaction mechanisms, electrode materials, and architectures to obtain dense, high performing stacks of micro SC-SOFCs.

Oxygen-Hydrogen PEM-based fuel cell systems are being examined as a portable power source alternative in addition to advanced battery technology. Fuel cell power systems have been used by the Gemini, Apollo, and Space Shuttle programs. These systems have not been portable, but have been integral parts of their spacecraft, and have used reactants from a separate cryogenic supply. These systems typically have been higher in power. They also have had significant ancillary equipment sections that perform the pumping of reactants and coolant through the fuel cell stack and the separation of the product water from the unused reactant streams. The design of small portable fuel cell systems will be a significant departure from these previous designs. These smaller designs will have very limited ancillary equipment, relying on passive techniques for reactant and thermal management, and the reactant storage will be an integral part of the fuel cell system. An analysis of the mass and volume for small portable fuel cell systems was done to evaluate and quantify areas of technological improvement. A review of current fuel cell technology as well as reactant storage and management technology was completed to validate the analysis and to identify technology challenges.

Oxygen-Hydrogen PEM-based fuel cell systems are being examined as a portable power source alternative in addition to advanced battery technology. Fuel cell power systems have been used by the Gemini, Apollo, and Space Shuttle programs. These systems have not been portable, but have been integral parts of their spacecraft, and have used reactants from a separate cryogenic supply. These systems typically have been higher in power. They also have had significant ancillary equipment sections that perform the pumping of reactants and coolant through the fuel cell stack and the separation of the product water from the unused reactant streams. The design of small portable fuel cell systems will be a significant departure from these previous designs. These smaller designs will have very limited ancillary equipment, relying on passive techniques for reactant and thermal management, and the reactant storage will be an integral part of the fuel cell system. An analysis of the mass and volume for small portable fuel cell systems was done to evaluate and quantify areas of technological improvement. A review of current fuel cell technology as well as reactant storage and management technology was completed to validate the analysis and to identify technology challengesBurke, Kenneth A.Glenn Research CenterFUEL CELLS; CRYOGENICS; TEMPERATURE CONTROL; ELECTRIC BATTERIES; NASA PROGRAMS; SPACE SHUTTLES

A novel approach to realize a miniature fuel cell power source by combining thin film solid-oxide or proton exchange membrane electrolyte-electrode materials with MEMS techniques to integrate a fuel cell stack monolithically on a manifolded host structure is described. This architecture enable a scalable, portable fuel cell power source system for a broad range of applications having power requirements in the 1 W to 10 W regime. The MEMS approach offers a direct means to integrate the fuel cell stack with required manifolding and fuel delivery system, while providing the means to control the performance of the power source for specific applications. Results describing the fabrication, integration, and testing of MEMS-based fuel cells are presented below.