CN1706064A

CN1706064A - Fuel cell system and method for producing electrical energy

Info

Publication number: CN1706064A
Application number: CNA2003801016577A
Authority: CN
Inventors: 克里斯托弗·K·戴尔
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-10-17
Filing date: 2003-10-15
Publication date: 2005-12-07
Also published as: EP1554768A2; CA2501735A1; FI20050389A; WO2004036667A3; AU2003301472A1; BR0315399A; WO2004036667A2; KR20050052533A; AU2003301472A8; ES2299324A1; ES2299324B1; JP2006503414A

Abstract

A fuel cell system has a fuel cell (6) disposed within a fuel cell enclosure (5) for electrochemically combining externally supplied oxygen with hydrogen to produce direct-current electrical energy and water as a reaction product. A hydrogen-containing fuel (1) such as a chemical hybride contained within a fuel container (2) receives the by-product water and reacts therewith to produce hydrogen, which is supplied to the fuel cell (6) to sustain operation thereof without the need of adding externally supplied hydrogen. The integration of the supply of hydrogen with the fuel cell results in a weight and volume reduction as well as internal chemical control of the production of hydrogen to sustain the electrical power generation and internal water management whereby liquid water emission is substantially reduced.

Description

Fuel cell system and method for generating electrical energy

Technical Field

The present invention relates generally to fuel cells, and more particularly to fuel cells that consume gaseous hydrogen-containing fuel and produce electrical energy and water.

Background

Typically, fuel cells produce water during normal power generation by electrochemically combining oxygen in air with hydrogen to produce electrical energy using well-known electrochemical principles. U.S. patent nos. 4,863,813, re34,248; convenient fuel cells for energy conversion are described in 4,988,582 and 5,094,928. In fuel cells of the type described herein, a hydrogen-containing species (e.g., a gaseous mixture of hydrogen and oxygen) at room temperature is converted directly into direct current electrical energy, with water being the only reaction product.

In one such specific illustrative fuel cell, an electrolyte membrane made of pseudo-boehmite permeable to a gas of submicron thickness and having ion conductivity is deposited on an electrode composed of a platinized impermeable substrate. A layer of platinum is deposited on the top surface of the electrolyte membrane to form the other electrode of the fuel cell, which is porous enough to allow the entry of the gas mixture into the electrolyte membrane. Such a fuel cell can provide an effective current of about 1 volt of output voltage in a hydrogen/air mixture. While alkaline fuel cells provide voltages and currents sufficient for many applications of practical interest, the applicants of the present invention have recognized that there is a need to design a small hydrogen source suitable for use with a variety of fuel cells, particularly for portable electronic applications such as laptop computers and mobile phones. A suitable combination of fuel cells with a light, low-capacity hydrogen source can provide an improved power source suitable for portable electronic device applications, as compared to batteries.

A variety of chemical hydride materials with high hydrogen content can react with water to generate hydrogen gas. The combined weight and volume of the chemical hydride and the water required to react with it to form the hydrogen gas for the fuel cell is referred to as the "specific energy" content of the fuel, which is typically measured in watt-hours (energy content) divided by the weight or volume of the chemical hydride plus the reactant water required by it. Thus, watt-hours per kilogram or watt-hours per liter are examples of specific energies of fuels used by fuel cells. In the case of portable applications, the fuel cell and its fuel would benefit from the use of high specific energy fuels, which would reduce the weight and volume of the fuel cell system load.

The applicant of the present invention believes that a fuel cell capable of utilizing this byproduct water as a reactant for reaction with a chemical hydride would be advantageous to increase the specific energy of the fuel cell system, since the fuel cell generates water as a byproduct in the normal course of its power generation, thus eliminating the need to load additional water. Thus, only one reactant, i.e., chemical hydride, needs to be loaded in the fuel cell system. The applicant believes that a fuel cell that is tolerant of air mixed with its fuel supply would particularly benefit from this method of generating hydrogen. The applicant of the present invention also believes that it would be desirable to have a chemical method of controlling the rate of hydrogen generation in such a fuel cell system. The applicant of the present invention further believes that a portable fuel cell system would benefit from a means for collecting water produced during normal power generation, thereby avoiding moisture and flooding in the vicinity of the operating fuel cell.

Disclosure of Invention

The present invention enables operation of a fuel cell with a hydrogen fuel resulting from the reaction of a chemical fuel (e.g., a chemical hydride) with water, a byproduct from the fuel cell. The combination of this fueling method with a suitable fuel cell constitutes an apparatus known as a fuel cell system characterized in that it requires only an external supply of oxygen or air and has a specific energy density higher than that of that fuel cell system which requires a separate or additional source of water. The present invention improves the performance, control and safety of fuel cell systems in which a fuel cell is combined with a fuel supply in accordance with the principles of the present invention by internally utilizing the water product of the fuel cell itself. The improved performance of the device is characterized by a higher specific energy content (in terms of weight and volume). This improvement is achieved by eliminating the need to add additional water for reacting with the chemical hydride to generate hydrogen.

Another advantage of the present invention is that it can control the rate of hydrogen generation by controlling the water supply to the chemical hydride. The supply of water required for the reaction with the hydrogen-containing chemical fuel is controlled by the required electrical energy. In the present invention, a fuel cell that produces water vapor during its operation is combined with a suitable chemical hydride(defined as a hydrogen-containing fuel that reacts with water vapor to produce hydrogen gas under the same environmental conditions as the fuel cell), which does not require a separate source of water other than the water supplied by the fuel cell. In the present invention, water vapor exhausted from the fuel cell is directed to a container containing a suitable chemical hydride material where it reacts to form hydrogen gas, which is then supplied to the anode of the fuel cell to sustain the generation of electrical energy.

However, a typical fuel cell produces water mixed with air at the cathode or anode, and thus the product of the reaction of the exhaust of such a typical fuel cell with a chemical hydride will contain hydrogen and air. In these typical fuel cell designs, the fuel is required to be substantially uncontaminated by air. Therefore, in situations where the fuel cell requires hydrogen to be substantially uncontaminated by air at its anode or cathode, it is desirable to have an additional means of separating water vapor from air or hydrogen from air so that only substantially unmixed air hydrogen is delivered to the anode of the fuel cell.

Advantageously, fuel cells that not only produce water vapor, but also require mixing of air and hydrogen to produce electrical energy, would particularly benefit from the present invention, since operation of such fuel cells does not require separation of water from air or separation of hydrogen from air. Examples of such fuel cells are described in U.S. patent nos. 4,863,813, re34,248; 4,988,582 and 5,094,928. Such a fuel cell in combination with the present invention will constitute a preferred embodiment. Other fuel cells that would advantageously benefit from the present invention would be another fuel cell capable of producing water that is not mixed with air, for example, a fuel cell that produces water on the anode, or negative side of the cell, also typically accompanied by hydrogen on the anode or negative side, which is an example of a solid oxide fuel cell.

Since the fuel cell produces by-product water in direct proportion to the amount of electrical energy produced, the water supply in the present invention can be regulated by the electrical energy demand. In the present invention, the chemical fuel (e.g., chemical hydride) is preferably selected to require the same amount of reactant water as the fuel cell produces to maintain operation of the fuel cell. This therefore also prevents excessive and costly production of hydrogen gas, which can be a control, which is advantageous both for saving residual chemical hydride material and for safety. Also, the chemical hydride is preferably selected on the basis that the fuel cell provides sufficient water supply to react all of the chemical hydride. For a given amount of generated electrical energy, the rate of hydrogen generation required for fuel cell use can be fully balanced by the amount of water produced by the fuel cell when using the preferred chemical hydride. As the demand for electrical energy increases, more current can be produced with the concomitant production of more water, which through reaction with the chemical hydride results in the production of more hydrogen to maintain a higher demand for electrical energy. When the electrical energy demand drops to zero, the amount of water produced is correspondingly reduced to zero, and as a result, the amount of hydrogen is also reduced to zero, which provides a safe method of storing and transporting hydrogen. The present invention thus advantageously provides a method for efficient and safe control of the amount of hydrogen produced.

Another advantage of the present invention is the use of a solid hydrogen-containing fuel that effectively absorbs product water from the fuel cell, thereby avoiding humidification and flooding from the vicinity of the operating fuel cell outlet. A variety of inorganic chemical hydrides can react with water vapor to produce hydrogen and produce solid products, which is an advantageous "water management" method of the present invention. A further subsidiary advantageous feature of the invention is that it provides a method of measuring the residual energy content of a fuel. For fuel cells using the present invention, hydrogen generation may be accompanied by an increase in weight and volume within the chemical hydride container. This physical change can be monitored by simple gravimetric or volumetric methods to provide a range of reaction rates for the chemical hydride and, therefore, the remaining energy content of the system.

The foregoing and other objects, features and advantages of the present invention will become readily apparent to those skilled in the art from the following detailed description of the invention when read in conjunction with the accompanying drawings.

Drawings

FIG. 1 is a simplified schematic diagram of a fuel cell system according to the principles of the present invention; and

fig. 2 is an exemplary diagram illustrating a reaction that occurs during operation of the fuel cell system shown in fig. 1 using air as an oxygen source.

Detailed Description

Fuel cell incorporating a fuel supply

An example of a fuel cell system according to the present invention is shown in fig. 1. The fuel cell system comprises a hydrogen-containing fuel 1, e.g. NaBH, contained in a fuel container 2₄A chemical hydride fuel. The fuel container 2 has an inlet 3 for introducing water, primarily in the form of water vapour, into the container 2 for reaction with the hydrogen-containing fuel 1 to produce hydrogen gas which exits the container 1 via an outlet 4.

The interior of the fuel cell housing 5 is provided with a fuel cell 6, which may be U.S. patent No. 4,863,813, re43,248; 4,988,582 and 5,094,928, the entire disclosures of which form part of the present disclosure and are incorporated herein by reference. An example of such a fuel cell 6 is shown in figure 1 and consists of a mixed gas fuel cell having an impermeable substrate 18, an impermeable or permeable catalytic electrode 17, a permeable ion-conducting and electronically insulating electrolyte membrane 16 (referred to as a solid electrolyte body in the inventor's prior patent of the present application) and a permeable catalytic electrode 15. According to the prior patent disclosures (from which the term thin film fuel cell is used in conjunction with the patent disclosures described in these documents), the

catalytic electrodes

15 and 17 and the electrolyte membrane 16 are typically thin. In contrast, the substrate 18 is typically thicker than the thin film fuel cell because it mechanically supports the thin film fuel cell. The substrate 18 may also be effectively conductive. The fuel cell 6 is provided with a pair of lead wires 6a, 6b for extracting the electrical energy generated by the fuel cell, the lead wires 6a, 6b being connected to the fuel cell electrodes in a manner known in the art. The fuel cell case 5 is provided with: an oxygen inlet 7 for introducing oxygen into the housing; a hydrogen inlet 8 for introducing hydrogen into the housing; and a water outlet 9 for discharging water from the housing. Preferably, an inlet valve 10 is provided in the oxygen inlet 7 for controlling the inflow of oxygen.

In the embodiment shown in fig. 1, the outlet 4 of the fuel container 2 is directly connected to the hydrogen inlet 8 of the fuel cell housing 5 by a conduit 11. In this way, the interior of the fuel container 2 communicates with the interior of the fuel cell housing 5, so that hydrogen gas generated by the fuel 1 can be discharged through the outlet 4 and introduced into the fuel cell housing 5 through the conduit 11 and the hydrogen gas inlet 8. In this embodiment, a further conduit 12 communicates the water outlet 9 of the fuel cell housing 5 with the inlet 3 of the fuel container 2. This enables water produced during operation of the fuel cell 6 to be introduced into the fuel container 2 for reaction with the hydrogen-containing fuel 1. If desired, a blow valve 14 may be provided along the conduit 12.

During operation, oxygen or air is introduced into the fuel cell housing 5 through the inlet valve 10 (in the open position) and the oxygen inlet 7 and mixed with hydrogen introduced through the hydrogen inlet 8 to form a gas mixture required by the fuel cell 6 to generate electrical energy, which is transmitted along the leads 6a, 6b connected to the fuel cell electrodes. A corresponding amount of water vapor is generated by the fuel cell 6 and exits the fuel cell housing 5 through the water outlet 9 and is then transported to the hydrogen-containing fuel 1 via the inlet 3 by the conduit 12. The water vapor reacts with the hydrogen-containing fuel 1 in the fuel container 2 and produces more hydrogen gas that is delivered to the fuel cell 6 to maintain the generation of electrical energy.

Although the primary purpose of inlets 7 and 8 and outlet 9 is to pass the primary fuel cell reactants oxygen and hydrogen and product water, respectively, in practice, other gases may accompany the primary reactants and products. For example, gases other than water that are not reacted by the fuel cell 6 (including unreacted oxygen and hydrogen) may be transported through the outlet 9 and then transported in an unreacted state through the fuel 1, the container 2, the outlet 4, the conduit 11, and the inlet 8 into the fuel cell housing 5. If air is used as the oxygen source, nitrogen will also be transported in an unreacted state through the various components of the fuel cell system shown in fig. 1 and further shown in fig. 2. Due to normal fuel cell operation, air will eventually become depleted in oxygen.

In order to maintain a directed flow pattern, oxygen or air can be forced into the fuel cell housing 5 through the oxygen inlet 7 with the inlet valve 10 open. This can be achieved by using part of the electrical energy generated by the fuel cell 6. It may also be desirable to incorporate a purge valve 14 to enable the removal of oxygen-depleted air from the fuel cell enclosure 5 and replacement with oxygen-enriched air via the oxygen inlet 7.

A variation of the arrangement in figure 1 may include the removal of

valves

10 and 14, and the removal of outlet 4, inlet 8 and

conduits

11 and 12, such that the fuel cell housing 5 is connected directly to the fuel container 2. One or more openings (e.g., outlet 9) provided in the fuel cell housing 5 will align with a similar opening (e.g., inlet 3) provided in the fuel container 2 so that air diffusing through the oxygen inlet 7 will mix with hydrogen diffusing from the fuel container 2 to provide the mixed gas environment required for the fuel cell 6 to generate power, and water vapor diffusing from the fuel cell housing 5 will enter the fuel container 2 to react with the hydrogen-containing fuel 1. This device variant will enable a simpler design and produce lower energy levels suitable for use in low power portable devices such as cellular portable radiotelephones. The higher energy levels required during transmission of a cellular portable radiotelephone can be provided by a small battery, which is stably charged by a low power fuel cell system.

According to another aspect of the present invention, the fuel container 2 is removably attached to the fuel cellsystem so that it can be removed and replaced with a new fuel container. For this purpose, any suitable detachable connection, such as a screw connection or a bolted flange connection, may be used to detachably connect the inlet 3 and the outlet 4 of the fuel container 2 to the

conduits

11 and 12. In embodiments where the outlet 4, inlet 8, and

conduits

11 and 12 are not used, the fuel container 2 would be removably attached directly to the fuel cell housing 5 so that the outlet 9 of the fuel cell housing 5 could communicate directly with the inlet 3 of the fuel container 2. If desired, a plurality of aligned outlets 9 and inlets 3 may be provided in the housing 5 and container 2, respectively. Alternatively, the conduit 12 may be left, in which case only the inlet 3 of the fuel container 2 needs to be detachably connected to the conduit 12. In this way, the spent fuel container 2 can be removed and replaced with a new fuel container.

The reaction sequence involved in the fuel cell system of fig. 1 is shown in the gas flow diagram of fig. 2:

in the fuel cell 6:

in the fuel container 2:

and (3) total reaction:

the overall reaction means that the fuel cell system shown in fig. 1 generates electrical energy from only one external reactant (oxygen, readily available from air) and no excess hydrogen is generated, except for the hydrogen that is internally required for electrical energy generation. The reaction also illustrates that the cells of the fuel cell produce water in an amount sufficient to react all of the chemical hydride material. The internal circulation of water and hydrogen generation can be directly controlled and regulated bythe external demand of electrical energy, which makes the system intrinsically safe. The cycle may have the following characteristics: for a given amount of electrical energy produced, the rate of hydrogen generation required for fuel cell use can be fully balanced by the amount of water produced by the cell when using the appropriate chemical hydride. As the demand for electrical energy increases, more current can be produced with the concomitant production of more water, resulting in more hydrogen gas being produced to maintain a higher demand for electrical energy. When the demand for electrical energy drops to zero, the amount of water produced correspondingly drops to zero, and as a result, the amount of hydrogen also drops to zero, which makes the system very safe for storage and transport of hydrogen with the inlet valve 10 closed.

For fuel cells capable of generating electrical energy in a mixture of gas exposed to air and 2% to 4% hydrogen, for example, U.S. patent nos. 4,863,813, re43,248; 4,988,582 and 5,094,928 would benefit from the invention in particular because the air has the same range of water vapor carrying capacity, i.e., a water vapor content of 2% to 4% over a temperature range of 20 ℃ to 30 ℃. This particular advantage arises because, in the reaction shown above, the reaction of a given number of water molecules with a chemical hydride can produce the same number of hydrogen molecules, thus naturally controlling the amount of hydrogen produced to be in the range of 2% to 4%, which is generally considered to be the allowable amount of hydrogen in air, which is particularly useful in portable electronic device applications, such as mobile phones and laptop computers. Furthermore, supplying water in vapor form is an advantageous method to most effectively utilize chemical hydride fuels.

As shown in fig. 1, the inlet valve 10 prevents uncontrolled ingress of air or oxygen into the fuel cell system when the system is not in use. The inlet valve 10 typically comprises a shut-off valve that is actuated mechanically or electrically when the fuel cell 6 is no longer delivering power. The air release valve 14 will also be closed when the fuel cell 6 is not operating to produce electrical power.

The present invention combines a fuel cell with a chemical fuel through an inlet and outlet system that eliminates the need to supply external water to react with the chemical hydride. The fuel cell system of the present invention is thus reduced in weight and reduced in volume by the amount of water corresponding to the unwanted water, which for sodium borohydride amounts to a saving of about two thirds of weight and volume. This is clearly advantageous for portable applications. The specific energy density based on the hydrogen content of sodium borohydride by itself (excluding the volume or weight of reactant water) was about 6300 watt-hours/liter and 5900 watt-hours/kg. Other chemical hydrides, if used in accordance with the present invention, may provide higher energy densities.

Fuel

A number of suitable inorganic chemical hydrides can react with water in an equilibrium manner to benefit the invention and produce hydrogen, some examples of which are given below.

These are examples of suitable fuels for use in the present invention. Their choice will also depend on factors including their specific energy density, rate of reaction with water vapor, and rate of reaction with water vaporIntegrity of the vapor reaction, temperature, etc. Sufficiently high specific energy densities can be obtained by using lithium-based hydrides, e.g. LiBH₄Its energy density was about 10,000 watt-hours/liter and 10,000 watt-hours/kg. If it is used in the present invention, the energy density will be much higher than that of common fuel cell fuels, such as methanol, and higher than that of heavier metal hydrides, which adsorb and desorb hydrogen, as opposed to the chemical hydride fuels used in the present invention, which react with water to generate hydrogen.

A preferred embodiment of the invention will include a means of utilizing as much of the chemical hydride fuel as possible with the water vapor provided by the fuel cell. If the water supplied to the chemical hydride from the fuel cell is in a vaporized state, it will help penetrate into the solid chemical hydride mass, enabling a more consistent degree of reaction (high utilization) of the available solid chemical hydride as compared to liquid water. Specifically, the vaporized water reduces the occurrence of vapor path blockage of the solid chemical hydride particulate matter, which would otherwise reduce the energy density of the system by preventing further contact of the water with the interior particles of the chemical hydride.

It is advantageous to mix particles of the chemical hydride with an inert material that enhances the ingress and permeation of water vapor. Judicious selection of the particle size and particle size distribution of the chemical hydride is also advantageous for high utilization. Increasing the porosity of the chemical hydride fuel to water vapor can be accomplished by forming the chemical hydride into sheets or films, where the voids between the individual sheets or films are easily accessible to water vapor, thereby promoting a higher degree and uniformity of reaction of the chemical hydride. The reaction rate of solid chemical hydride fuels can be increased by adding additives to the chemical hydride, such as catalysts for the reaction, including the addition of ruthenium or acid-containing compounds.

The addition of a fusible polymer to the chemical hydride particles is advantageous for safety by selecting a polymer that will melt and spread to the remaining chemical hydride fuel when the temperature rises to an unacceptable level, which will prevent the barrier from further reacting with the incoming water vapor, thereby reducing the rate of reaction of the water vapor with the chemical hydride fuel.

While it is contemplated that the primary source of hydrogen is obtained by the reaction of a hydrogen-containing fuel with water, the rate of hydrogen generation may decrease as the fuel gradually reacts, and thus, the fuel cell may require a supplemental hydrogen supply to maintain an unreduced power output.

Water management and disposal

All fuel cells that use hydrogen and oxygen to generate electrical energy produce water that at ambient temperatures will concentrate and collect on the electrodes, thereby degrading the performance of the electrodes by preventing the flow of reactant gases to the catalytic surfaces of the electrodes. This is usually prevented by increasing the airflow to displace the water. The present invention removes water vapor without requiring an increase in air flow and internally reduces the formation of condensed water by acting as a "drying" agent in the vicinity of the fuel cell. This is particularly advantageous in the case of fuel cell applications close to the human body and equipment, which are very susceptible to moisture formation.

The present invention contemplates the removal of water that has been generated from spent chemical hydride fuel and from chemical reactions by mechanical means. The fuel container 2 of fig. 1 is designed to be simply and efficiently removed and replaced with a container containing unreacted chemical hydride. For the present invention, disposal with spent sodium borohydride, a solid borax, is not a problem.

Although the preferred embodiments of the present invention have been described with reference to mixed gas fuel cells, it should be understood that the present invention is not so limited and can be practiced using a wide variety of fuel cells that consume hydrogen and produce water as a reaction product. For example, the invention may be practiced using fuel cells that require different electrochemical reactants or different concentrations of electrochemical reactants at the cathode and anode, so long as the fuel cells consume hydrogen and produce water as a reaction product.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method of generating direct current electrical energy comprising the steps of:

operating the fuel cell to electrochemically combine externally supplied oxygen with hydrogen to produce direct current electrical energy and water as a reaction product;

directing the water through a hydrogen-containing fuel that reacts with the water to generate hydrogen gas; and

directing the hydrogen gas to the fuel cell to maintain operation of the fuel cell.

2. The method of claim 1, wherein the fuel cell is a thin film fuel cell.

3. The method of claim 1, wherein water produced by operating the fuel cell exists primarily in the form of water vapor; and, the hydrogen-containing fuel reacts with the water vapor to generate hydrogen gas.

4. The method of claim 3, wherein the fuel cell is a thin film fuel cell.

5. The method of claim 4, wherein the hydrogen-containing fuel is a chemical hydride.

6. The method of claim 5, wherein the chemical hydride is selected from the group consisting of NaBH₄、CaH₂、LiBH₄And LiAlH₄Group (d) of (a).

7. The method of claim 1, wherein the hydrogen-containing fuel is a chemical hydride.

8. The method of claim 7, wherein the chemical hydride is selected from the group consisting of NaBH₄、CaH₂、LiBH₄And LiAlH₄Group (d) of (a).

9. A method as claimed in claim 1, wherein the hydrogen-containing fuel is selected relative to the fuel cell such that the water produced by operating the fuel cell is sufficient to react substantially all of the hydrogen-containing fuel.

10. A method as claimed in claim 1, wherein sufficient hydrogen gas is generated by reacting the hydrogen-containing fuel with water generated by operating the fuel cell to maintain operation of the fuel cell without the need for adding externally supplied hydrogen gas.

11. The method of claim 1, wherein the hydrogen-containing fuel comprises one or more additives to increase and/or decrease the rate of reaction of the hydrogen-containing fuel with water.

12. A fuel cell system for producing direct current electrical energy, comprising: a housing having an oxygen inlet, a hydrogen inlet, and a water outlet; a fuel cell disposed in the housing for electrochemically combining oxygen introduced through the oxygen inlet and hydrogen introduced through the hydrogen inlet to produce direct current electrical energy and generating water as a reaction product; the hydrogen-containing fuel is communicated with the water outlet and is used for reacting with the water discharged from the water outlet to generate hydrogen; and a conduit interconnecting the fuel cell and the hydrogen gas inlet for directing the hydrogen gas generated from the hydrogen-containing fuel to the fuel cell to maintain operation of the fuel cell.

13. The fuel cell system of claim 12, further comprising a fuel container containing the hydrogen-containing fuel therein, the fuel container having an inlet in communication with the water outlet and an outlet in communication with the conduit.

14. The fuel cell system of claim 13, wherein the fuel container is removable from the fuel cell system and replaceable with another fuel container containing a hydrogen-containing fuel.

15. The fuel cell system according to claim 14, wherein the fuel container is detachably attached to the housing.

16. The fuel cell system of claim 13, further comprising another conduit interconnecting the water outlet of the housing and the inlet of the fuel container.

17. The fuel cell system of claim 16, further comprising a vent valve disposed along the another conduit.

18. The fuel cell system of claim 17, further comprising an inlet valve for controlling the introduction of oxygen through the oxygen inlet.

19. The fuel cell system of claim 12, further comprising an inlet valve for controlling the introduction of oxygen through the oxygen inlet.

20. The fuel cell system of claim 12, wherein the hydrogen-containing fuel is a chemical hydride.

21. The fuel cell system of claim 20, wherein the chemical hydride is selected from the group consisting of NaBH₄、CaH₂、LiBH₄And LiAlH₄Group (d) of (a).

22. The fuel cell system according to claim 12, wherein the fuel cell includes a mixed gas fuel cell.

23. The fuel cell system of claim 12, wherein the fuel cell comprises a thin film fuel cell.

24. The fuel cell system of claim 12, wherein the hydrogen-containing fuel includes one or more additives to increase and/or decrease the rate ofreaction of the hydrogen-containing fuel with water.