JP2001006697A - Fuel cell and fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply hydrogen gas to a fuel cell in an amount complying with the requested output even in the case the electric output value required of a fuel cell varies in the size. SOLUTION: A fuel cell system 1 is configured so that hydrogen gas is supplied from a gas supply source 2 to fuel cells (stack) 3, wherein between the gas source 2 and fuel cells 3, a surge preventing means 5 is installed which accumulates the hydrogen gas or its pressure from the gas source 2 when the hydrogen gas consumption of the fuel cells 3 is lesser and releases the accumulated gas or its pressure when the gas consumption is large. A hydrogen occluding means, for example consisting of hydrogen storage alloy, is installed on the negative electrode part of the fuel cells 3 or in its neighbourhood.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fuel cell that generates electric energy by a reaction between hydrogen gas and oxygen gas, and a fuel cell system including the same.

[0002]

2. Description of the Related Art In a fuel cell, hydrogen as a negative electrode active material is brought into contact with a catalyst such as platinum (platinum) to dissociate it into electrons and protons, and then this proton is reacted with oxygen as a positive electrode active material to produce water. Is obtained based on the reaction mechanism. That is, in the fuel cell, an electromotive force is generated by the movement of electrons released from hydrogen on the negative electrode side.

[0003] Based on such a principle, a chemical energy change can be directly converted into electric energy, so that the energy efficiency is extremely high as compared with other power generation methods. This means that the fuel cell has less energy loss than the internal combustion engine based on the Carnot cycle, and is useful as a drive source for a motor for an electric vehicle, which is an alternative to the internal combustion engine. In fuel cells, the exhaust gas is mainly water vapor, and no harmful gases such as nitrogen compounds, hydrocarbons and carbon monoxide are emitted as in internal combustion engines. Practical use of the electric vehicle as a source is desired.

[0004] The fuel cell is not generally used alone, but constitutes a fuel cell system together with means for supplying hydrogen to the fuel cell. As shown in FIG. 3, for example, this fuel cell system is generally configured to include a fuel cell stack 3 in which a plurality of fuel cells are stacked in series, and a hydrogen gas supply source 2. In the illustrated fuel cell system 1, the hydrogen gas supply source 2 is configured so that the raw material methanol is subjected to steam reforming and hydrogen gas is supplied as a hydrogen-rich fuel gas. Specifically, the hydrogen gas supply source 2 includes a methanol tank 20, a water tank 21, and a reformer 22.
The reformer 22 further includes a steam generator 22a for evaporating water from the water tank 21 and a methanol tank 2
And a reforming unit 22b that obtains a hydrogen-rich fuel gas from methanol by contacting methanol from water with steam from a steam generation unit 22a, and converts carbon monoxide contained in the fuel gas into carbon dioxide to convert the fuel gas into carbon dioxide. It has a metamorphic portion 22c for reducing toxicity and an air blower 22d.
The fuel cell stack 3 is supplied with fuel gas generated by the reforming device 22 by obtaining propulsion from the air blower 22d, and is supplied with air (oxygen gas) by the compressor 4. And in the fuel cell stack 3,
Electric energy is obtained by the reaction between fuel gas (hydrogen gas) and air (oxygen gas).

[0005]

Such a fuel cell system 1 is incorporated in, for example, an electric vehicle and used as a drive source for a motor. In this case, the electrical output value required for the fuel cell stack 3 is the motor load,
That is, although it depends on the running state of the vehicle, the load required for the motor varies because the running state of the vehicle is not uniform. Therefore, if the electric output of the fuel cell stack 3 can be made to correspond to the load demand of the motor, the energy efficiency of the fuel cell system 1 will be extremely improved. However, in the air blower 22d or the like, it is difficult to feed a certain amount or more of fuel gas (hydrogen gas) into the fuel cell stack 3, and the fuel cell stack 3 cannot obtain an output of a certain value or more. Cannot cope with a situation where the load demand is large.

The present invention has been conceived in view of the above circumstances, and has been developed for the fuel cell even when the magnitude of the electrical output value required for the fuel cell varies. Therefore, it is an object of the present invention to supply a hydrogen gas that can supply a required output.

[0007]

DISCLOSURE OF THE INVENTION In order to solve the above-mentioned problems, the present invention takes the following technical means.

That is, the fuel cell provided by the first aspect of the present invention comprises a negative electrode section for dissociating hydrogen gas into hydrogen ions and electrons, an electrolytic section for allowing the transfer of hydrogen ions, and hydrogen ions, electrons, and oxygen. Each of the positive electrode units for generating water by reacting a gas includes a first plate provided with a hydrogen gas supply unit and a second plate provided with an oxygen gas supply unit.
A fuel cell provided between the first plate and the electrolysis unit, wherein a part of the hydrogen gas from the hydrogen gas supply means is stored between the first plate and the electrolytic unit, and the hydrogen gas is stored if necessary. Hydrogen storage means for releasing the hydrogen gas is provided.

The hydrogen storage means of the fuel cell has a tendency to store hydrogen when the amount of hydrogen around the negative electrode is excessive, and to release the stored hydrogen when the amount of hydrogen is insufficient. . Therefore, not only when a fuel cell is used in a system in which hydrogen gas is constantly supplied and electric energy is constantly extracted, but also when a load request such as a driving source of a motor of an electric vehicle is used. Even under the situation where fluctuates, it is possible to cope with the fluctuation of the load demand by storing and releasing hydrogen by the hydrogen storage means. In other words, under conditions of large load demands, the hydrogen gas around the negative electrode is quickly consumed, and the directly supplied hydrogen gas is likely to fall into a state of hydrogen deficiency. , Can be supplemented by hydrogen released from the hydrogen storage means.

Here, the hydrogen storage means may be any means capable of storing hydrogen by a physical or chemical method. For example, a hydrogen storage alloy may be used. This hydrogen storage alloy stores hydrogen in the atmosphere in accordance with the atmospheric conditions (pressure and temperature of the atmosphere, etc.) and the hydrogen storage state of the hydrogen storage alloy (the actual amount of hydrogen stored with respect to the maximum hydrogen storage amount). Or have the ability to release hydrogen into the atmosphere.

By the way, under a situation where the load demand is large,
As described above, the inside of the fuel cell, particularly around the negative electrode part, tends to fall into a state where the amount of hydrogen gas is deficient, and tends to fall into a state where the pressure is lower than a steady state. In this state, the hydrogen storage alloy is in a state where hydrogen is easily released, and the stored hydrogen is actively released around the negative electrode part, and the hydrogen storage alloy automatically responds to the state of lack of hydrogen gas. Becomes That is, in the means using the hydrogen storage alloy, hydrogen storage and storage of hydrogen are performed according to the hydrogen concentration around the negative electrode part, that is, the electric output required for the fuel cell, without providing a separate means for detecting the hydrogen gas concentration. By repeating the release, it is possible to appropriately cope with the output fluctuation required for the fuel cell.

As the hydrogen storage alloy, for example, those listed in the following table can be mentioned.
Any of these hydrogen storage alloys can be used. The following table shows the composition of the hydrogen storage alloy in the state of a hydride having the maximum hydrogen storage.

[0013]

[Table 1]

By the way, the first plate and the second plate are provided not only to define and secure an area functioning as a battery between these plates, but also to provide a hydrogen gas supply means and an oxygen gas supply means. Is used to supply hydrogen gas or oxygen gas. For this reason, it is required to have excellent heat resistance so as to be able to cope with the heat generated in the portion functioning as a battery, and to be hardly corroded by hydrogen gas or oxygen gas and have high mechanical strength.
For example, it is formed by processing various metals and alloys (titanium, stainless steel, titanium alloy, and the like).

The positive electrode portion and the negative electrode portion have, for example, a structure including a catalyst layer and a current collector, or an electrode portion (a positive electrode portion or a negative electrode portion) having both functions as a catalyst layer and a current collector. It may be configured such that an element corresponding to the catalyst layer and an element corresponding to the current collector are integrally formed. In the negative electrode portion, the hydrogen storage alloy may be integrally formed in the negative electrode portion by dispersing and fixing the powder or particles of the hydrogen storage alloy to the catalyst layer, the current collector, or the entire negative electrode portion.

In the structure in which the catalyst layer and the current collector are formed separately, the catalyst layer may have a structure in which a catalyst is supported on a porous carrier, for example. It may be applied directly to the surface of the part.

As the method of forming the former catalyst layer, for example, the following two methods can be considered. The first method is a method in which conductive particles such as carbon particles, on which catalyst powder is previously supported, are solidified to form a porous matrix, which is used as a catalyst layer. The second method is to solidify conductive particles such as carbon particles to form a porous matrix, then impregnate the porous matrix with a solution containing a catalyst component, and heat-treat the solution so that the catalyst is supported on the matrix. This is a method of forming a layer.

As described above, the hydrogen storage alloy powder or particles may be fixed to the catalyst layer and the hydrogen storage means may be provided integrally with the catalyst layer. For example, the first
When the catalyst layer is formed by the above method, the fixing of the hydrogen storage alloy is performed, for example, as follows. That is, before solidifying the conductor particles carrying the catalyst powder, the catalyst-carrying conductor particles and the powder or particles of the hydrogen storage alloy are mixed, and the mixture is solidified, whereby the hydrogen storage means is integrated with the catalyst layer. Is provided. On the other hand, when the catalyst layer is formed by the second method, the conductive particles and the powder or particles of the hydrogen storage alloy are mixed before forming the porous matrix in which the conductive particles are solidified, and the mixture is solidified. By doing
A hydrogen matrix may be formed integrally with the catalyst layer by forming a porous matrix integrally provided with the hydrogen storage means and supporting a catalyst on the porous matrix. In addition, a porous matrix is formed only by the conductive particles, and a powder or particles of the hydrogen storage alloy are mixed with the solution containing the catalyst component to form a slurry. By doing so, the hydrogen storage alloy may be supported on the porous matrix together with the catalyst component.

The latter catalyst layer is formed by screen-printing an ink which is a paste or suspension of a carbon powder as a carrier supporting the catalyst with an organic solvent or a mixture of the catalyst and the carbon powder with an organic solvent. It is formed by applying to the electrolytic part by such a method as described above and evaporating the solvent component. Further, a carbon thin film to be a catalyst layer may be formed on a water-repellent sheet made of a fluororesin or the like by a method such as screen printing and drying, and then this may be thermally transferred to an electrolytic portion to form a catalyst layer.

When the catalyst layer is formed by such a method, the powder or particles of the hydrogen storage alloy are previously mixed directly into the electrode portion or into the ink used for screen printing on the water-repellent sheet. With only this, the catalyst layer can be integrally provided with hydrogen storage means made of a hydrogen storage alloy.

In the catalyst layer of the positive electrode portion, it is necessary to react oxygen gas with hydrogen ions and electrons, so that the catalyst constituting the catalyst layer is, for example, platinum, gold, or the like.
Silver, rhodium, etc. are adopted. On the other hand, in the catalyst layer of the negative electrode section, it is necessary to dissociate hydrogen gas into hydrogen ions and electrons, and therefore, for example, platinum, gold, nickel, tungsten carbide, or the like is employed as a catalyst constituting the catalyst layer.

In a configuration in which the catalyst layer and the current collector are formed separately, the current collector in the positive electrode portion allows oxygen gas to pass therethrough to reach the catalyst layer in the positive electrode portion. It has a function of supplying electrons to the catalyst layer of the part. On the other hand, the current collector of the negative electrode part has a function of passing hydrogen gas to reach the catalyst layer of the negative electrode part and collecting electrons generated in the catalyst layer of the negative electrode part. For this reason, the current collector is required to have an appropriate porosity and be a good electronic conductor. Of course, it is also required to have excellent mechanical strength and to be hardly affected by the electrolyte. The constituent materials of the current collector satisfying such requirements include carbon-based materials (carbon powder such as carbon black and carbon fiber, etc.), nickel, nickel-chromium alloy, nickel-cobalt alloy,
Silver, titanium, tantalum, oxide semiconductors, and the like can be given. For example, it is preferable that these materials are formed into a porous matrix by solidifying conductive particles, and in the case of carbon fibers, it is preferable to form a current collector in a cloth-like form.

In the current collector having the above structure,
As described above, the hydrogen storage means may be provided integrally. When the current collector is configured as a porous matrix, the hydrogen storage means is formed by, for example, the same method as in the case of the catalyst layer configured as a porous matrix.

Of course, the hydrogen storage means is not provided integrally with the negative electrode portion including the catalyst layer and the current collector, but is provided separately from the negative electrode portion, for example, between the first plate and the negative electrode portion. Is also good. In this case, the hydrogen storage means is provided with an excellent air permeability so that the hydrogen gas from the hydrogen gas supply means provided on the first plate can reach the negative electrode portion through the hydrogen gas supply means. For example, a porous body or a mesh-like form is preferable. When the hydrogen storage means is configured as a porous body, for example, by sintering the powder or granules of the hydrogen storage alloy or solidifying it using a binder, and using an appropriate porous matrix as a carrier, the hydrogen storage alloy is used. The hydrogen storage means may be formed as a porous body by supporting and fixing the powder or the particles of the above. Also,
In the case of a mesh-like form, for example, a hydrogen-absorbing means is formed by processing a plate-like hydrogen-absorbing alloy, or by holding and fixing powder or granules of the hydrogen-absorbing alloy on a mesh-like carrier. May be formed as a porous body.

The electrolysis section contains an electrolyte that allows the transfer of hydrogen ions, such as a solid polymer,
Examples include an alkaline solution, a solution of a super strong acid or phosphoric acid, a carbonate, or a solid oxide.

The solid polymer is formed, for example, in the form of a film or a sheet to form an electrolytic portion. A polystyrene-based cation exchange membrane, for example, a perfluorosulfonic acid polymer is preferably used. This polymer exhibits proton conductivity when wetted with water, and protons (hydrogen ions) generated by dissociation of hydrogen gas in the negative electrode catalyst layer pass through the electrolytic portion by permeation in a hydrated state, It moves to the positive electrode catalyst layer.

Examples of the alkaline solution include potassium hydroxide solution, and examples of the super-strong acid solution include fluoroethane disulfonic acid solution, difluoromethane disulfonic acid solution, difluoromethane diphosphonic acid solution, trifluoromethane sulfonic acid solution, trifluoromethane sulfonic acid solution and trifluoromethane sulfonic acid solution. An ethanesulfonic acid solution, a tetrafluoroethanedisulfonic acid solution, a tetrafluoropropanesulfonic acid solution, or the like can be given.

The alkaline solution, the superacid solution or the phosphoric acid solution is used as an electrolytic part by impregnating and holding a powder such as silicon carbide in a porous matrix bound with a resin such as polytetrafluoroethylene.

Examples of the carbonate include sodium carbonate, potassium carbonate, lithium carbonate and the like. These may be used alone, or a plurality of kinds may be mixed and used as a mixed molten salt. The carbonate is mixed with, for example, lithium aluminate particles and hot-pressed at a temperature about 10 ° C. lower than the melting point of the carbonate, or impregnated into a lithium aluminate plate to form an electrolytic part. In this electrolysis part, the carbonate is melted by operating at a high temperature to become a carbonate ion conductor.

As the solid oxide, zirconium oxide,
Examples include calcium oxide, yttrium oxide, ytterbium oxide, scandium oxide, neodymium oxide, gadolinium oxide, and lanthanum oxide. Among these solid oxides, zirconium oxide is particularly preferably used, and zirconium oxide in zirconium oxide may be partially substituted with other solid oxide constituent atoms to form a solid solution.

The fuel cell according to the present invention can be used as a fuel cell stack by stacking a plurality of fuel cells in series. In a fuel cell stack, the same plate can be shared between adjacent fuel cells. In this case, a hydrogen gas supply unit is provided on one side of the shared plate, and an oxygen gas supply unit is provided on the other side.
Also, the hydrogen gas supply means of each plate are connected to each other, and the oxygen gas supply means are communicated with each other.If hydrogen gas is supplied from one place, hydrogen gas flows through all the hydrogen gas supply means of each plate, and so on. Alternatively, if the oxygen gas is supplied from one place, the oxygen gas may flow through all the oxygen gas supply means of each plate. Further, the shared plate may be formed of a conductor and may be configured to conduct to both the positive electrode current collector of one fuel cell and the negative electrode current collector of the other fuel cell.
In this configuration, the electrons collected in the negative electrode current collector of the other fuel cell are supplied to the positive electrode current collector of one fuel cell via a shared plate, and the electrons are collected by the positive electrode catalyst layer of the one fuel cell. Will contribute to the water production reaction.

According to a second aspect of the present invention, there is provided a fuel cell system configured to pump hydrogen gas from a hydrogen gas supply source to a fuel cell, wherein the hydrogen gas supply source and the fuel cell And storing the hydrogen gas or pressure from the hydrogen gas supply source when the consumption of hydrogen gas in the fuel cell is low, and storing the hydrogen gas or pressure when the consumption of hydrogen gas in the fuel cell is high. A fuel cell system is provided, which is provided with surging preventing means for releasing.

In this configuration, similarly to the fuel cell provided with the hydrogen storage means described in the first aspect of the present invention, it is possible to appropriately cope with fluctuations in the electric output required of the fuel cell. In other words, when the electric output required of the fuel cell is large, the stored hydrogen gas is released by the surging prevention means to substantially increase the supplied hydrogen concentration, or the stored pressure is released to release the supplied hydrogen gas. This can be dealt with by increasing the flow rate of the hydrogen gas.

The surging preventing means includes a so-called surge tank which can store a certain amount of hydrogen gas and pressure, and a hydrogen storing means made of the hydrogen storing alloy described in the first aspect of the present invention. And the like.

Examples of the hydrogen gas supply source include a cylinder filled with hydrogen gas, a hydrogen storage alloy storing hydrogen, and a device for reforming hydrocarbons to generate hydrogen gas.

[0036] Other features and advantages of the present invention will become more apparent from the detailed description that follows.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be specifically described below with reference to FIG. 1 or FIG. FIG. 1 is a block diagram illustrating an example of a fuel cell system according to the present invention, and FIG. 2 is a cross-sectional view illustrating a fuel cell.

As shown in FIG. 1, the fuel cell system 1
Is generally provided with a hydrogen gas supply source 2, a fuel cell stack 3, and an air supply means 4.

The hydrogen gas supply source 2 comprises, for example, a methanol tank 20, a water tank 21, and a reformer 22. The reformer 22 further includes a steam generating section 22a, a reforming section 22b, a shift section 22c, and an air blower 22d. , And a burner 22e.

The steam generating section 22a mainly serves to heat water from the water tank 21 by the heat from the burner 22e to vaporize the water. Then, the methanol from the methanol tank 20 is also supplied to the steam generating section 22a, and the temperature of the methanol is raised at the same time. The burner fuel used was a methanol tank 20
Of methanol is used.

Thus, the steam generated in the steam generating section 22a and the heated methanol are introduced into the reforming section 22b by the propulsive force from the air blower 22d. The reforming section 22b further includes an air supply means 4
Is also supplied.

The reforming section 22b reforms methanol heated in the steam generating section 22a to generate hydrogen gas, and a catalyst suitable for reforming is filled in the reforming vessel. Examples of the catalyst used in this case include a Cu-Zn catalyst and a Ni-based catalyst, and these catalysts are usually filled in a reforming container while being supported on a wire mesh or a honeycomb carrier. I have. And Cu-Z
When the n catalyst is used, about 250 to 3
When the Ni-based catalyst is used at about 00 ° C., about 800 to 90
Heat to 0 ° C. For heating the reforming section 22b, for example, heat from a burner 22e provided in the steam generating section 22a is used.

In the reforming section 22b having such a configuration, a steam reforming reaction (reaction formula below) which is a reaction with steam is performed.
(1)) occurs as a main reaction, and a partial oxidation (combustion) reaction which is a reaction with oxygen gas (air) (reaction formula (2) below)
Occur in competition, and hydrogen gas is generated by these reactions.

[0044]

Embedded image

As is apparent from these reaction formulas (1) and (2), if a steam reforming reaction or a partial oxidation reaction occurs, carbon dioxide is produced as a by-product simultaneously with hydrogen gas. If the oxidation is insufficient, carbon monoxide is also by-produced. As described above, in the reforming unit 22b, the supplied methanol generates a hydrogen-rich fuel gas containing carbon monoxide and carbon dioxide, and this fuel gas is supplied to the shift unit 22c by the propulsive force from the air blower 22d. be introduced. At the same time, air from the air supply means 4 is introduced into the shift section 22c.

The metamorphic section 22c serves to oxidize carbon monoxide to carbon dioxide. For example, a catalyst such as iron-chromium or copper-zinc is supported on a suitable carrier such as a wire mesh. In this case, the fuel cell is filled in the shift vessel. In a later-described fuel cell 30 (see FIG. 2), a reaction between hydrogen gas and oxygen gas usually occurs in the presence of platinum as a catalyst, but carbon monoxide has an effect of poisoning platinum. For this reason, since it is desirable that the concentration of carbon monoxide of the fuel gas supplied to the fuel cell 30 be as low as possible, in the conversion unit 22c, the carbon monoxide is converted into carbon dioxide by, for example, the action of a catalyst. This fuel gas is sent to the three-way valve 10 by the propulsion from the air blower 22d. The three-way valve 10 has a state in which fuel gas is supplied to the fuel cell stack 3 and a bypass switching valve 11.
And a state in which the air is supplied to the burner 40 of the air supply means 4 through the air conditioner.

A surging preventing means 5 is provided between the three-way valve 10 and the fuel cell stack 3 in order to cope with a change in the cell output required for the fuel cell stack 3, that is, a change in the concentration of the consumed fuel gas. I have. The surging prevention means 5 includes, for example, a pump 50 and a surging tank 5.
1. Mass flow controller 52 and control means 53
It has. The pump 51 is for pumping the fuel gas sent to the three-way valve 10 to the fuel cell stack 3 under pressure. The surge tank 51 stores the fuel gas or pressure when the fuel gas consumption in the fuel cell stack 3 is small, and discharges the stored fuel gas or pressure when the fuel gas consumption is large. Control means 53
Controls the mass flow controller 52, that is, the flow rate, according to the electrical output required for the fuel cell stack 3.

When the output demand for the fuel cell stack 3 is large, a large amount of hydrogen gas is required in the fuel cell stack 3. It is easy for the individual fuel cells 30 to fall into a state where hydrogen gas is deficient.
On the other hand, in the fuel cell system 1 provided with the surge tank preventing means 5 described above, when the output demand for the fuel cell stack 3 is large, the fuel gas in the surge tank 51 is supplied, and This corresponds to a state of hydrogen gas deficiency in the fuel cell 30. In this way, the fuel gas whose flow rate is adjusted by the mass flow controller 52 is supplied to the fuel cell stack 3 in accordance with the electric output required for the fuel cell stack 3. At the same time, air from the air supply means 4 is introduced into the fuel cell stack 3.

As shown in FIG. 2, the fuel cell stack 3 has a plurality of fuel cells 30 stacked in series. Each fuel cell 30 has a configuration in which a positive electrode portion 31, a negative electrode portion 32, and an electrolytic portion 33 are sandwiched between a pair of plates 34,34. And the adjacent fuel cell 3
0 share one plate 34,
The plate 34 is substantially partitioned.

The positive electrode part 31 and the negative electrode part 32 are
1a and 32a and catalyst layers 31b and 32b.
Each of the current collectors 31a and 32a is formed, for example, as a porous body in which conductive particles are solidified, and includes catalyst layers 31b and 32b.
Is formed, for example, by carrying a suitable catalyst powder such as platinum on a porous matrix composed of carbon particles. Although not shown in the drawing, at least one of the current collector 32a and the catalyst layer 32b of the negative electrode portion 32 is fixed with a powder of a hydrogen storage alloy as hydrogen storage means. This hydrogen storage alloy stores and releases hydrogen according to the atmospheric conditions. For this reason, the electric output required for the fuel cell stack 3 is large, and the amount of hydrogen gas consumed in each fuel cell 30 is large. Is released. On the other hand, when the output required for the fuel cell stack 3 is not so large, the hydrogen storage alloy stores a part of the supplied hydrogen. As described above, in the fuel cell 30 in which the hydrogen storage means is provided in the negative electrode part 32, and eventually in the fuel cell stack 3, even if the required output becomes large, it is necessary to appropriately cope with the above-mentioned surging prevention means 5. Can be.

Each plate 34 is formed of, for example, stainless steel or a titanium alloy, and has a groove 34a for supplying a fuel gas (hydrogen gas) on one side, and an air (oxygen gas) supply on the other side. Groove 34b is provided. The fuel gas from the shift portion 22c is supplied to the negative electrode portion 32 through the respective grooves 34a and 34b.
Is supplied with air from the air supply means 4.
In the negative electrode part 32, hydrogen gas in the fuel gas is dissociated into hydrogen ions and electrons (reaction formula (3) below).
Oxygen gas in the air reacts with the electrons and the hydrogen ions moving through the electrolytic part 33 to produce water (the following reaction formula
(4)).

[0052]

Embedded image

The water thus generated is supplied to the burner 40 of the air supply means 4 together with the air discharged from the fuel cell stack 3, for example. Hydrogen gas that has not reacted in the fuel cell stack 3 is also supplied to the burner 40 via the bypass switching valve 11 and is used as burner fuel.

The air supply means 4 has a so-called turbo assist compressor 41 and a burner 40. The turbo assist compressor 41 has a motor M, a compressor C, and a turbine T, and the turbine T is rotated by a steam flow from the burner 40. The rotational force of the turbine T at this time is used for the compressor C, and electric power is applied to the motor M from a power source, and the compressor C operates. That is, the energy from the combustion of the unreacted hydrogen gas is used as the power source of the compressor C, and the energy applied externally via the power supply to operate the compressor C is minimized. I have. Then, as described above, the compressor C supplies air to the fuel cell stack 3 in addition to the reforming section 22b and the shift section 22c of the reforming device 22.

[0055]

As described above, in the fuel cell provided with the hydrogen storage means and the fuel cell system provided separately with the surging means of the present invention, when the electric output required for the fuel cell fluctuates. Even if there is, it can respond appropriately.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a fuel cell system according to the present invention.

FIG. 2 is a cross-sectional view illustrating a fuel cell.

FIG. 3 is a block diagram illustrating a conventional fuel cell system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuel cell system 2 Hydrogen gas supply source 3 Fuel cell stack 30 Fuel cell 31 Positive electrode part 32 Negative electrode part 32a Current collector (Negative electrode part) 32b Catalyst layer (Negative electrode part) 33 Electrolytic part 34 Plate 34a Groove part (Hydrogen gas supply) 34b Groove (as oxygen gas supply means) 4 Air supply means 5 Surging prevention means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01M 8/10 H01M 8/10

Claims (5)

[Claims] 1. A negative electrode section for dissociating hydrogen gas into hydrogen ions and electrons, an electrolytic section for allowing the transfer of hydrogen ions, and a positive electrode section for reacting hydrogen ions, electrons and oxygen gas to generate water, First hydrogen gas supply means provided
A fuel cell provided between the first plate and the second plate provided with the oxygen gas supply means, wherein the hydrogen gas supply means is provided between the first plate and the electrolysis section. A fuel cell, comprising: a hydrogen storage unit that stores a part of hydrogen gas and releases the stored hydrogen gas as needed. 2. The hydrogen occluding means is made of a hydrogen occluding alloy capable of occluding hydrogen gas in the atmosphere or releasing hydrogen gas into the atmosphere according to the atmosphere state and the hydrogen gas occlusion state. The fuel cell according to claim 1, wherein: 3. The negative electrode part has a negative electrode catalyst part to which a catalyst powder is fixed, and the hydrogen storage alloy is powdered and fixed to the catalyst part together with the catalyst powder. Item 3. The fuel cell according to Item 2. 4. The hydrogen storage means as a porous body in which the powdered hydrogen storage alloy is fixed between the first plate and the negative electrode part, or as a plate-shaped hydrogen storage means. 3. The fuel cell according to claim 2, wherein the fuel cell is provided as a mesh-like plate processed with an alloy. 5. A fuel cell system configured to pump hydrogen gas from a hydrogen gas supply source to a fuel cell, wherein a hydrogen gas in the fuel cell is provided between the hydrogen gas supply source and the fuel cell. A surging preventing means is provided for storing the hydrogen gas or pressure from the hydrogen gas supply source when the gas consumption is low, and releasing the stored hydrogen gas or pressure when the hydrogen gas consumption in the fuel cell is high. Characterized by a fuel cell system.