JP2014118336A - Fuel generator and fuel cell system equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel generator which generates a large amount of a fuel gas and which has high durability.SOLUTION: A fuel generator 1, in which a fuel gas, being a reducing gas, is generated by an oxidation reaction with an oxidizing gas, includes a plurality of units respectively comprising an intake valve 16, a housing part 17 to house a fuel generating member 19, and an exhaust valve 18. The plurality of units are connected in parallel to one another between a gas inlet 14 to which the oxidizing gas is supplied from the outside and a gas outlet 15 from which the fuel gas is supplied to the outside. In each of the units, when the exhaust valve 18 is set to a first opening, the intake valve 16 is set to a fourth opening, and when the exhaust valve 18 is set to a second opening smaller than the first opening, the intake valve 16 is set to a third opening larger than the fourth opening. A period during which the exhaust valve 18 is set to the first opening is staggered among the respective units.

Description

  The present invention relates to a fuel generator that generates a fuel gas that is a reducing gas by an oxidation reaction with an oxidizing gas, and a fuel cell system including the same.

  A fuel cell typically includes a solid polymer electrolyte membrane using a solid polymer ion exchange membrane, a solid oxide electrolyte membrane using yttria-stabilized zirconia (YSZ), a fuel electrode (anode) and an oxidizer electrode. The one sandwiched from both sides by the (cathode) has a single cell configuration. A fuel gas channel for supplying a fuel gas (for example, hydrogen) to the fuel electrode and an oxidant gas channel for supplying an oxidant gas (for example, oxygen or air) to the oxidant electrode are provided. Electric power is generated by supplying the fuel gas and the oxidant gas to the fuel electrode and the oxidant electrode, respectively.

  Fuel cells are not only energy-saving because of the high efficiency of the power energy that can be extracted in principle, but they are also a power generation system that excels in the environment, and are expected as a trump card for solving global energy and environmental problems.

Japanese National Patent Publication No. 11-501448 International Publication No. 2012/043271 International Publication No. 2012/026219

  Patent Documents 1 to 3 disclose secondary battery fuel cell systems that combine a solid oxide fuel cell and a hydrogen generating member that generates hydrogen by an oxidation reaction and can be regenerated by a reduction reaction. Yes. In the secondary battery type fuel cell system, the hydrogen generating member generates hydrogen during the power generation operation of the system, and the hydrogen generating member is regenerated during the charging operation of the system.

  In the above secondary battery type fuel cell system, there can be considered a usage method in which a plurality of accommodating portions for accommodating the hydrogen generating member are provided and the number of accommodating portions to be used is changed according to the power generation demand.

  In addition, as a form of the hydrogen generating member, for example, a form in which hydrogen is generated by an oxidation reaction and a fine particle having a metal as a base material that can be regenerated by a reduction reaction is left solidified with a gap that allows gas to pass through, or the above fine particle may be used. The form which shape | molds into a pellet-shaped particle | grain and is filled with many this particle | grain in space is mentioned.

  When gas is supplied to a plurality of storage units connected in parallel, the gas does not spread uniformly to all the storage units, but flows in a concentrated manner in the storage units with a small pressure loss. As a result, since the accommodating part with a large pressure loss is not effectively used, the amount of generated fuel gas is reduced, and the accommodating part with a small pressure loss is concentrated and utilized, so that the accommodating part with a small pressure loss is concentrated. There was a problem that the durability deteriorated due to deterioration. In particular, when the form of the hydrogen generating member is a form in which a large number of pellet-like particles are filled in the internal space of the accommodating part, since the filling is random, there is a large variation in pressure loss between the accommodating parts, and the above problem It is remarkable.

  In view of the above situation, an object of the present invention is to provide a fuel generator that generates a large amount of fuel gas and has high durability, and a fuel cell system including the fuel generator.

  In order to achieve the above object, a fuel generator according to the present invention is a fuel generator that generates a fuel gas that is a reducing gas by an oxidation reaction with an oxidizing gas, and the oxidizing gas is supplied from the outside. A gas inlet for supplying the fuel gas to the outside, a fuel generating member for generating the fuel gas by an oxidation reaction with the oxidizing gas, and the gas inlet and the gas outlet A storage portion provided between the storage portion and the gas generation port; an intake valve provided between the gas inlet and the storage portion; and an exhaust valve provided between the storage portion and the gas outlet. Comprising a plurality of units constituted by the intake valve, the accommodating portion, and the exhaust valve, the plurality of units being connected in parallel, and the opening of the exhaust valve in each of the units When the exhaust valve is changed to the first opening periodically, including the first opening and the second opening smaller than the first opening, the intake valve is changed to the third opening. When the exhaust valve is set to the second opening, the intake valve is set to a fourth opening that is larger than the third opening, and the exhaust valve is set to the first opening for each unit. It is set as the structure (1st structure) which shifts the period made into an opening degree.

  In the fuel generator of the first configuration, a configuration (second configuration) in which an overlapping period between units having different periods in which the opening degree of the exhaust valve is set to the first opening degree can be changed. Also good. The overlap period may be zero.

  In the fuel generation device having the first or second configuration, the length of a cycle in which the opening degree of the exhaust valve periodically changes including the first opening degree and the second opening degree is changed. A configuration that can be used (second configuration) may be used.

  In the fuel generator of any one of the first to third configurations, when the opening degree of the exhaust valve is switched from the second opening degree to the first opening degree, the opening degree of the exhaust valve is gradually increased. The configuration may be larger (fourth configuration).

  In the fuel generator of the fourth configuration, when the opening of the exhaust valve is switched from the second opening to the first opening, the opening of the exhaust valve is changed from the second opening to the first opening. You may make it the structure (5th structure) which can change the time taken until it switches to a 1st opening degree.

  In the fuel generation device having any one of the first to fifth configurations, the first opening degree may be changed (sixth configuration).

  In the fuel generator of any one of the first to sixth configurations, the length of the period during which the opening of the exhaust valve is set to the first opening is the amount of the fuel generating member for each unit. You may make it the structure (7th structure) set to the length according to.

  The fuel generation device having any one of the first to seventh configurations may include a gas stirrer provided between the plurality of units and the gas outlet (eighth configuration).

  The fuel generator having any one of the first to eighth configurations may include a check valve (9th configuration) provided with a check valve provided between the gas inlet and the plurality of units.

  In order to achieve the above object, a fuel cell system according to the present invention includes a fuel generator having any one of the above-described configurations and a fuel cell device that generates electric power using fuel gas supplied from the fuel generator. And

  Moreover, the fuel cell system having the above-described configuration may include a smoothing unit that smoothes the generated power of the fuel cell device.

  According to the fuel generator of the present invention, in the unit in which the exhaust valve is set to the first opening and the intake valve is set to the third opening, the inflow of gas to the unit is suppressed, and the gas is discharged from the unit. It becomes possible. Further, according to the fuel generator of the present invention, in the unit in which the exhaust valve is set to the second opening and the intake valve is set to the fourth opening, the gas can flow into the unit. Since the discharge is suppressed, the average pressure in the housing portion rises, the gas spreads throughout the housing portion, and the reaction with the fuel generating member is reliably performed. In each unit, the opening degree of the exhaust valve periodically changes including the first opening degree and the second opening degree, and the unit sets the exhaust valve to the first opening degree for each unit. Therefore, in each unit, the reliable reaction between the gas flowing in and the fuel generating member and the discharge of the gas generated by the reaction are repeated in a state where the discharge period of the gas is shifted for each unit. . Thereby, it can prevent that gas concentrates on the accommodating part with small pressure loss, and flows. That is, since the accommodating portion having a large pressure loss is effectively utilized, the amount of fuel gas generated increases, the accommodating portions having a small pressure loss do not concentrate and deteriorate, and the durability of the fuel generating device increases.

  Further, according to the fuel cell system according to the present invention, since the fuel generating device according to the present invention is provided, the amount of fuel gas generated from the fuel generating device increases, and the battery capacity of the fuel cell system increases. The durability of the fuel generator is increased and the durability of the fuel cell system is also increased.

1 is a schematic diagram showing a schematic configuration of a secondary battery type fuel cell system according to a first embodiment of the present invention. It is a schematic diagram which shows the structure of the fuel generator which concerns on 1st Embodiment. It is a figure which shows the example of a manufacturing method of an accommodating part. It is a graph which shows the state of the exhaust valve in 1st Embodiment, and the state of an intake valve. It is a figure which shows the flow of the gas in the fuel generator in 1st Embodiment. It is a graph which shows the hydrogen supply amount in 1st Embodiment. It is a graph which shows the state of the exhaust valve and the state of an intake valve in 2nd Embodiment of this invention. It is a graph which shows the hydrogen supply amount in 2nd Embodiment. It is a schematic diagram which shows the structure of the fuel generator which concerns on 3rd Embodiment of this invention. It is a graph which shows the state of the exhaust valve in 3rd Embodiment, and the state of an intake valve. It is a graph which shows the hydrogen supply amount in 3rd Embodiment. It is a schematic diagram which shows the structure of the fuel generator which concerns on 4th Embodiment of this invention. It is a graph which shows the hydrogen supply amount in 4th Embodiment, and the hydrogen supply amount in 1st Embodiment. It is a schematic diagram which shows one structural example of a stirring part. It is a schematic diagram which shows the modification of the secondary battery type fuel cell system which concerns on 4th Embodiment. It is a graph which shows the state of the exhaust valve and the state of an intake valve in 5th Embodiment of this invention. It is a graph which shows the hydrogen supply amount in 5th Embodiment. It is a graph which shows the state of the exhaust valve in the modification of 6th Embodiment of this invention. It is a schematic diagram which shows the modification of a fuel generator. It is a schematic diagram which shows the other modification of a fuel generator. It is a schematic diagram which shows the other modification of a fuel generator.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, this invention is not restricted to embodiment mentioned later.

<First Embodiment>
FIG. 1 shows a schematic configuration of a secondary battery type fuel cell system according to the first embodiment of the present invention. The secondary battery type fuel cell system according to the present embodiment includes a fuel generator 1 having a fuel generating member (not shown in FIG. 1), a fuel cell unit 2, a heater 3 for heating the fuel cell unit 2, A container 4 that accommodates the fuel cell unit 2 and the heater 3, a pipe 5 for circulating gas between the fuel generator 1 and the fuel cell unit 2, and gas between the fuel generator 1 and the fuel cell unit 2. A pump 6 forcibly circulating, a heat insulating container 7, a pipe 8 for supplying air to the air electrode 2C of the fuel cell unit 2, and a pipe 9 for discharging air from the air electrode 2C of the fuel cell unit 2 And a system controller 10 for controlling the entire system. The heat insulating container 7 accommodates the fuel generator 1, the container 4, and a part of each of the pipes 5, 8, and 9.

  In addition, in order to prevent the figure from becoming complicated, illustration of a power line for transmitting power and a control line for transmitting control signals is omitted. A heater may be provided around the fuel generator 1 as necessary. Moreover, you may provide a temperature sensor etc. around the fuel generator 1 and the fuel cell part 2 as needed. Further, instead of the pump 6, other circulators such as a compressor, a fan, and a blower may be used.

As the fuel generating member included in the fuel generator 1, for example, a metal is used as a base material, and a metal or a metal oxide is added to the surface thereof. For example, hydrogen that can be regenerated by reductive reaction with a reducing gas (for example, hydrogen) can be used. Examples of the base metal include Ni, Fe, Pd, V, Mg, and alloys based on these, and Fe is particularly preferable because it is inexpensive and easy to process. Examples of the added metal include Al, Rd, Pd, Cr, Ni, Cu, Co, V, and Mo. Examples of the added metal oxide include SiO ₂ and TiO ₂ . However, the metal used as a base material and the added metal are not the same material. In the present embodiment, a fuel generating member mainly composed of Fe is used as the fuel generating member included in the fuel generating device 1.

The fuel generating member mainly composed of Fe can generate hydrogen as a fuel gas (reducing gas) by consuming water vapor as an oxidizing gas, for example, by an oxidation reaction represented by the following formula (1). .
4H ₂ O + 3Fe → 4H ₂ + Fe ₃ O ₄ (1)

When the oxidation reaction of iron shown in the above formula (1) proceeds, the change from iron to iron oxide proceeds and the remaining amount of iron decreases, but the reverse reaction of the above formula (1), that is, the following (2 The fuel generating member can be regenerated by the reductive reaction shown in the formula. The iron oxidation reaction shown in the above formula (1) and the reduction reaction in the following formula (2) can also be performed at a low temperature of less than 600 ° C.
4H ₂ + Fe ₃ O ₄ → 3Fe + 4H ₂ O (2)

  In the fuel generating member, it is desirable to increase the surface area per unit volume in order to increase the reactivity. As a measure for increasing the surface area per unit volume of the fuel generating member, for example, the main body of the fuel generating member may be made into fine particles and the fine particles may be molded. Examples of the fine particles include a method of crushing particles by crushing using a ball mill or the like. Further, the surface area of the fine particles may be further increased by generating cracks in the fine particles by a mechanical method or the like, and the surface area of the fine particles is further increased by roughening the surface of the fine particles by acid treatment, alkali treatment, blasting, etc. It may be increased.

  The fuel generating member may be, for example, a form in which fine particles are formed into pellet-like particles and a large number of these particles are filled in the space, and the fine particles are solidified with a space that allows gas to pass through. May be.

  As shown in FIG. 1, the fuel cell unit 2 has an MEA structure (membrane / electrode assembly) in which a fuel electrode 2B and an air electrode 2C as an oxidant electrode are bonded to both surfaces of an electrolyte membrane 2A. Although FIG. 1 illustrates a structure in which only one MEA is provided, a plurality of MEAs may be provided, or a plurality of MEAs may be stacked.

  As a material of the electrolyte membrane 2A, for example, a solid oxide electrolyte using yttria-stabilized zirconia (YSZ) can be used. Solid polymer electrolytes such as, but not limited to, those that pass hydrogen ions, those that pass oxygen ions, and those that pass hydroxide ions can be used as fuel cell electrolytes. Any material satisfying the characteristics may be used. In the present embodiment, an electrolyte that passes oxygen ions or hydroxide ions, for example, a solid oxide electrolyte using yttria-stabilized zirconia (YSZ) is used as the electrolyte membrane 2A.

  In the case of a solid oxide electrolyte, the electrolyte membrane 2A can be formed using an electrochemical vapor deposition method (CVD-EVD method; Chemical Vapor Deposition-Electrochemical Vapor Deposition) or the like. If there is, it can be formed using a coating method or the like.

  Each of the fuel electrode 2B and the air electrode 2C can be configured by, for example, a catalyst layer in contact with the electrolyte membrane 2A and a diffusion electrode laminated on the catalyst layer. As the catalyst layer, for example, platinum black or a platinum alloy supported on carbon black can be used. Further, as a material for the diffusion electrode of the fuel electrode 2B, for example, carbon paper, Ni—Fe cermet, Ni—YSZ cermet, or the like can be used. Moreover, as a material of the diffusion electrode of the air electrode 2C, for example, carbon paper, La—Mn—O-based compound, La—Co—Ce-based compound, or the like can be used. Each of the fuel electrode 2B and the air electrode 2C can be formed by using, for example, vapor deposition.

  In the following description, a case where hydrogen is used as the fuel gas will be described.

During power generation of the secondary battery type fuel cell system according to the present embodiment, the fuel cell unit 2 is electrically connected to an external load (not shown) under the control of the system controller 10. In the fuel cell unit 2, the following reaction (3) occurs in the fuel electrode 2B during power generation of the secondary battery type fuel cell system according to the present embodiment.
H ₂ + O ²⁻ → H ₂ O + 2e ⁻ (3)

The electrons generated by the reaction of the above formula (3) pass through an external load (not shown) and reach the air electrode 2C, and the reaction of the following formula (4) occurs in the air electrode 2C.
1 / 2O ₂ + 2e ⁻ → O ²⁻ (4)

And the oxygen ion produced | generated by reaction of said (4) Formula reaches | attains the fuel electrode 2B through electrolyte membrane 2A. By repeating the above series of reactions, the fuel cell unit 2 performs a power generation operation. Further, as can be seen from the above equation (3), during the power generation operation of the secondary battery type fuel cell system according to the present embodiment, H ₂ is consumed and H ₂ O is generated on the fuel electrode 2B side. .

From the above equations (3) and (4), the reaction in the fuel cell unit 2 during the power generation operation of the secondary battery type fuel cell system according to the present embodiment is as shown in the following equation (5).
H ₂ + 1 / 2O ₂ → H ₂ O (5)

On the other hand, the fuel generating member included in the fuel generating device 1 is formed on the side of the fuel electrode 2B of the fuel cell unit 2 during power generation of the secondary battery type fuel cell system according to the present embodiment by the oxidation reaction shown in the above formula (1). The H ₂ O produced in (1) is consumed to produce H ₂ .

  When the oxidation reaction of iron shown in the above formula (1) proceeds, the change from iron to iron oxide proceeds and the remaining amount of iron decreases. However, the fuel generation device is reduced by the reduction reaction shown in the above formula (2). 1 can be regenerated, and the secondary battery type fuel cell system according to the present embodiment can be charged.

When the secondary battery type fuel cell system according to the present embodiment is charged, the fuel cell unit 2 is connected to an external power source (not shown) under the control of the system controller 10. In the fuel cell unit 2, when the secondary battery type fuel cell system according to the present embodiment is charged, an electrolysis reaction represented by the following formula (6), which is a reverse reaction of the formula (5), occurs, and the fuel electrode 2B On the fuel side, H ₂ O is consumed and H ₂ is generated. In the fuel generating member provided in the fuel generator 1, the reduction reaction shown in the above equation (2) occurs, and is generated on the fuel electrode 2B side of the fuel cell unit 2. The consumed H ₂ is consumed to generate H ₂ O.
H ₂ O → H ₂ + 1 / 2O ₂ (6)

  Next, the structure of the fuel generator 1 in this embodiment is shown in FIG. The fuel generator 1 in the present embodiment has a configuration in which a first unit 11, a second unit 12, and a third unit 13 are connected in parallel between a gas inlet 14 and a gas outlet 15. Each unit has a configuration in which an intake valve 16, a housing portion 17, and an exhaust valve 18 are connected in series in this order from the gas inlet 14 side toward the gas outlet 15 side. A fuel generating member 19 is accommodated in the accommodating portion 17.

  As an example of the manufacturing method of the accommodating part 17, as shown to Fig.3 (a), after filling the container main body 20 with the fuel generation member pellet 21, it covers with the cover body 22, and as shown in FIG.3 (b) A method of connecting the body 22 and the container main body 20 by welding or the like and connecting three containers in series by welding or the like as shown in FIG. Regardless of the form in which the fuel generating member pellets 21 are filled, the pressure loss of the accommodating part 17 varies from one unit to another regardless of the form of the fuel generating member accommodated in the accommodating part 17. As described above, the reason why the pressure loss of the accommodating portion 17 is different for each unit is that it is easy to manage the amount of the fuel generating member. This is because the pressure loss of the accommodating portion 17 is not the same unless the microscopic structure and arrangement of the generating members are uniform.

  In this embodiment, control valves are used as the intake valve 16 and the exhaust valve 18, and the system controller 10 controls the opening degrees of the intake valve 16 and the exhaust valve 18 as follows.

  In each of the first to third units 11 to 13, the opening of the exhaust valve 18 is alternately switched between an opening corresponding to the fully open state and an opening corresponding to the fully closed state, and the exhaust valve 18 corresponds to the fully open state. When opening, the intake valve 16 is set to an opening corresponding to the fully closed state, and when the exhaust valve 18 is set to an opening corresponding to the fully closed state, the intake valve 16 is set to an opening corresponding to the fully opened state. Every time, the period of opening the exhaust valve 18 corresponding to the fully open state is shifted (see FIG. 4).

  That is, in one unit that discharges hydrogen with the exhaust valve 18 fully open, the intake valve 16 is fully closed to stop gas supply, and in the remaining two units, the intake valve 16 is fully open. And fill with gas. In the unit filled with gas, since the exhaust valve 18 is fully closed, the average pressure in the housing part 17 rises, and the gas spreads throughout the housing part 17 to ensure the reaction with the fuel generating member 19. Done. In the unit immediately after the exhaust valve 18 is switched from the fully closed state to the fully open state, and the intake valve 16 is switched from the fully open state to the fully closed state, the average pressure in the accommodating portion 17 is in a state of increasing. During this period, hydrogen can be discharged.

  Then, the unit for discharging hydrogen with the exhaust valve 18 fully opened is switched in the order of FIG. 5 (a) → FIG. 5 (b) → FIG. 5 (c) → FIG. 5 (a), and this switching cycle is repeated. To do. In FIG. 5, the thickness of the arrow indicates the gas flow rate, and the thicker the arrow, the greater the gas flow rate. In FIG. 5, the fully opened valve is painted white, and the fully closed valve is painted black.

  The cycle of switching the state of the exhaust valve 18 may be set according to the rated output of the fuel cell system, the amount of the fuel generating member 19, and the like. Normally, setting within a range of several seconds to several tens of seconds is assumed, but in some cases, a period of several minutes may be considered. In the present embodiment, the period during which the exhaust valve 18 is set to the opening corresponding to the fully open state has the same length in all units and does not overlap between different units.

  By controlling the opening degree of the intake valve 16 and the exhaust valve 18 described above, the amount of hydrogen supplied from the gas outlet 15 of the fuel generator 1 to the outside of the fuel generator 1 (gas inflow side of the fuel cell unit 2) is shown in FIG. As shown. In FIG. 6, the amount of hydrogen supplied from the gas outlet 15 of the fuel generator 1 to the outside of the fuel generator 1 (the gas inflow side of the fuel cell unit 2) is indicated by a solid line, and the hydrogen discharged from each unit The quantity is indicated by a broken line.

  In this embodiment, as shown in FIG. 6, in each unit, the hydrogen discharge period is shifted, and in each unit, the reliable reaction between the gas flowing in and the fuel generating member and the gas generated by the reaction are changed. The discharge is repeated. Thereby, it can prevent that gas concentrates on the accommodating part 17 with a small pressure loss, and flows. That is, since the accommodating portion 17 having a large pressure loss is effectively used, the amount of fuel gas generated is increased, the accommodating portion 17 having a small pressure loss is not concentrated and deteriorated, and the durability of the fuel generator 1 is high. Become.

  Further, in the present embodiment, the fuel generator 1 always generates hydrogen that is equal to or greater than the first predetermined amount (minimum guaranteed amount) V1 (except when the oxidation of the fuel generating member 19 proceeds to a predetermined ratio or more). Therefore, the fuel generator 1 can cope with the power generation of the fuel cell unit 2 that requires the first predetermined amount (minimum guaranteed amount) V1 or less of hydrogen.

Second Embodiment
The schematic configuration of the secondary battery type fuel cell system according to the second embodiment of the present invention is the same as the schematic configuration of the secondary battery type fuel cell system according to the first embodiment shown in FIG. Moreover, the structure of the fuel generator 1 in this embodiment is also the structure shown in FIG. 2 like the structure of the fuel generator 1 in 1st Embodiment.

  In the present embodiment, unlike the first embodiment, the period of opening the exhaust valve 18 corresponding to the fully opened state is partially overlapped between different units (see FIG. 7). As a result, The switching cycle of the state of the exhaust valve 18 is shorter than that in the first embodiment. As a result, the period during which hydrogen is discharged from a plurality of units is lengthened, and as a result, the fuel generator 1 has a second predetermined amount (minimum guaranteed amount) V2 that is greater than the minimum guaranteed amount V1 in the first embodiment. Hydrogen can be generated at all times (except when the oxidation of the fuel generating member 19 proceeds to a predetermined rate or more) (see FIG. 8). Thereby, the generated electric power of the fuel cell unit 2 can be increased as compared with the first embodiment.

  The length of the overlap period between units having different opening periods corresponding to the fully open state of the exhaust valve 18 is adjusted according to the demand power determined by the system controller 10 based on an external instruction or the like. Is desirable. That is, when the demand power is large, the overlap period is lengthened, and when the demand power is small, the overlap period is shortened or zero as in the first embodiment. In addition, when shortening an overlap period or making it zero like 1st Embodiment, since the switching cycle of the state of the exhaust valve 18 becomes long, the continuous use time of the fuel generator 1 can be increased.

<Third Embodiment>
The schematic configuration of the secondary battery type fuel cell system according to the third embodiment of the present invention is the same as the schematic configuration of the secondary battery type fuel cell system according to the first embodiment shown in FIG. Further, as shown in FIG. 9, the configuration of the fuel generator 1 in the present embodiment is such that the amount of the fuel generating member 19 accommodated in the accommodating portion 17 of the second unit 12 is equal to the accommodating portion 17 of the first unit 11. The fuel generating member in which the amount of the fuel generating member 19 accommodated in the accommodating portion 17 of the first unit 11 is larger than the amount of the fuel generating member 19 accommodated in the accommodating portion 17 of the third unit 13. This is different from the first embodiment in that the amount of the fuel generating member 19 in each unit is equal in that it is larger than the amount of 19.

  As described above, in the present embodiment, the amount of the fuel generating member 19 varies from unit to unit, so that the exhaust valve 18 is set to an opening corresponding to the fully open state, as in the first and second embodiments. Is the same for all units, the amount of hydrogen discharged from each unit depends on the amount of the fuel generating member 19, and the amount of hydrogen discharged from the fuel generating device 1 varies greatly. End up.

  Therefore, in this embodiment, the system controller 10 stores in advance the amount of the fuel generating member 19 accommodated in the accommodating portion 17 of each unit, and the amount of the fuel generating member 19 accommodated in the accommodating portion 17. Accordingly, the length of the period during which the exhaust valve 18 is opened corresponding to the fully opened state is adjusted. Specifically, the period in which the exhaust valve 18 of the second unit 12 having the largest amount of the fuel generating member 19 accommodated in the accommodating portion 17 is set to an opening corresponding to the fully opened state is lengthened, and the accommodating portion 17 is The period during which the exhaust valve 18 of the third unit 13 having the smallest amount of the fuel generating member 19 accommodated is set to an opening corresponding to the fully opened state is shortened (see FIG. 10).

  That is, a unit with a small amount of the fuel generating member 19 accommodated in the accommodating portion 17 is accommodated by filling the gas for a long time by extending the period during which the exhaust valve 18 has an opening corresponding to the fully closed state. The gas discharge time is shortened by increasing the average pressure in the portion 17 and shortening the period during which the exhaust valve 18 is opened at an opening corresponding to the fully open state. As a result, a large flow of gas is discharged from the unit with a small amount of the fuel generating member 19 accommodated in the accommodating portion 17 for a short time. On the contrary, for a unit having a large amount of the fuel generating member 19 accommodated in the accommodating portion 17, the period during which the exhaust valve 18 is opened corresponding to the fully closed state is shortened, and the exhaust valve 18 is fully opened. Increase the opening period corresponding to. As a result, a small amount of gas is discharged from the unit having a large amount of the fuel generating member 19 accommodated in the accommodating portion 17 for a long time.

  Even if the amount of the fuel generating member 19 accommodated in the accommodating portion 17 of each unit differs by adjusting the length of the period during which the exhaust valve 18 is set to an opening corresponding to the fully opened state, the fuel Variations in the amount of hydrogen discharged from the generator 1 can be reduced (see FIG. 11). Thereby, the minimum guaranteed amount V3 of hydrogen discharged from the fuel generator 1 can be increased.

<Fourth embodiment>
The schematic configuration of the secondary battery type fuel cell system according to the fourth embodiment of the present invention is the same as the schematic configuration of the secondary battery type fuel cell system according to the first embodiment shown in FIG. Moreover, the structure of the fuel generator 1 in this embodiment is the structure which added the stirring part 23 which stirs gas to the fuel generator 1 used in 1st Embodiment, as shown in FIG. The stirring unit 23 is provided between each unit and the gas outlet 15. Thereby, since the fluctuation | variation of the hydrogen amount supplied to the stirring part 23 from each unit can be absorbed by the stirring part 23, from the gas outlet 15 outside the fuel generator 1 (gas inflow side of the fuel cell part 2) Fluctuation in the amount of hydrogen supplied to can be reduced (see FIG. 13). Therefore, the minimum guaranteed amount V4 of hydrogen discharged from the fuel generator 1 can be made larger than the minimum guaranteed amount V1 in the first embodiment. In FIG. 13, the amount of hydrogen supplied from the gas outlet 15 of the fuel generating device 1 in the present embodiment to the outside of the fuel generating device 1 (the gas inflow side of the fuel cell unit 2) is indicated by a solid line. The amount of hydrogen supplied from the gas outlet 15 in the embodiment to the outside of the fuel generator 1 (the gas inflow side of the fuel cell unit 2) is indicated by a broken line.

  The opening control of the intake valve 16 and the exhaust valve 18 of the present embodiment is the same as the opening control of the intake valve 16 and the exhaust valve 18 of the first embodiment.

  Here, one structural example of the stirring unit 23 is shown in FIG. In FIG. 14, the gas flow is schematically shown by arrows. In the configuration example shown in FIG. 14, the stirring unit 23 is configured by an expansion chamber 26 in which a gas inlet 24 and a gas outlet 25 are provided.

  The cross-sectional area of the expansion chamber 26 (the area of the cross section of the expansion chamber 26 perpendicular to the direction of travel of the gas flowing into the gas inlet 24) is the cross-sectional area of the gas inlet 24 (flows into the gas inlet 24). The cross-sectional area of the gas inlet 24 perpendicular to the gas traveling direction) and the cross-sectional area of the gas outlet 25 (the cross-sectional area of the gas outlet 25 perpendicular to the traveling direction of the gas flowing out from the gas outlet 25) Bigger than each of.

  Due to the difference in the cross-sectional area of the flow path, the gas pressure in the expansion chamber 26 becomes lower than the gas pressure in the pipe 5, and the gas is dispersed and stirred in all directions in the expansion chamber 26.

  Instead of the stirring unit 23, a smoothing unit 27 that smoothes the generated power of the fuel cell unit 2 may be provided as shown in FIG. In this case, since the fuel generator 1 has the configuration shown in FIG. 2, the amount of hydrogen supplied from the gas outlet 18 of the fuel generator 1 to the outside of the fuel generator 1 (the gas inflow side of the fuel cell unit 2). Although the fluctuation is not reduced, the output voltage of the secondary battery type fuel cell system can be stabilized as in the case where the fluctuation is reduced.

  As an example of the smoothing unit 27, a low-pass having a cutoff frequency lower than the fluctuation frequency of the amount of hydrogen supplied from the gas outlet 15 of the fuel generator 1 to the outside of the fuel generator 1 (gas inflow side of the fuel cell unit 2). A filter can be mentioned.

  Moreover, it is also possible to provide both the stirring unit 23 and the smoothing unit 27 in the secondary battery type fuel cell system according to the present invention. In this case, the output voltage of the secondary battery type fuel cell system can be further stabilized.

<Fifth Embodiment>
The schematic configuration of the secondary battery type fuel cell system according to the fifth embodiment of the present invention is the same as the schematic configuration of the secondary battery type fuel cell system according to the first embodiment shown in FIG. Moreover, the structure of the fuel generator 1 in this embodiment is also the structure shown in FIG. 2 like the structure of the fuel generator 1 in 1st Embodiment.

  In the present embodiment, unlike the first embodiment, when the state of the exhaust valve 18 is switched from the fully closed state to the fully open state, the opening degree is gradually increased without instantaneous switching (see FIG. 16). Thereby, since the pressure accumulated in the accommodating portion 17 can be gradually released, overshoot of the amount of hydrogen discharged from the unit immediately after the exhaust valve 18 is switched from the fully closed state to the fully open state is suppressed. (See FIG. 17). As a result, fluctuations in the amount of hydrogen supplied from the gas outlet 18 of the fuel generator 1 to the outside of the fuel generator 1 (the gas inflow side of the fuel cell unit 2) can be reduced. In FIG. 17, the amount of hydrogen supplied from the gas outlet 15 of the fuel generator 1 to the outside of the fuel generator 1 (the gas inflow side of the fuel cell unit 2) is indicated by a solid line, and the hydrogen discharged from each unit The quantity is indicated by a broken line.

  As shown in FIG. 16, the opening control of the intake valve 16 in each unit is a reversal control of the opening control of the exhaust valve 18 in each unit, and when the state of the intake valve 16 is switched from the fully open state to the fully closed state. The opening degree may be gradually reduced without switching instantaneously, and when the state of the intake valve 16 is switched from the fully open state to the fully closed state as in FIGS. May be.

<Sixth Embodiment>
The schematic configuration of the secondary battery type fuel cell system according to the sixth embodiment of the present invention is the same as the schematic configuration of the secondary battery type fuel cell system according to the first embodiment shown in FIG. Moreover, the structure of the fuel generator 1 in this embodiment is also the structure shown in FIG. 2 like the structure of the fuel generator 1 in 1st Embodiment.

  When the demand power is small, it is desirable to reduce the minimum guaranteed amount of hydrogen discharged from the fuel generator 1. As a method of reducing the minimum guaranteed amount of hydrogen discharged from the fuel generator 1 when the demand power is small, the output of the pump 6 is lowered when the demand power is small, and the amount of gas supplied to the fuel generator 1 A method of reducing the potential is conceivable. However, the pump 6 is optimized for the output required when the demand power is a normal value, and there is a problem that the efficiency of the pump 6 is reduced when the output of the pump 6 is lowered. Further, if the output of the pump 6 is changed frequently, there is a problem that the life of the pump 6 is shortened.

  Therefore, in the present embodiment, the amount of hydrogen discharged from the fuel generator 1 is suppressed when the power demand is small while the output of the pump 6 is kept constant. Specifically, in each unit, the state of the exhaust valve 18 is switched when the power demand is small while the ratio between the period in which the exhaust valve 18 is fully open and the period in which the exhaust valve 18 is fully closed is kept constant. The cycle (for example, the period T shown in FIG. 16) is lengthened. In this case, the period during which the average pressure in the accommodating portion 17 increases increases, and the reaction between the gas and the fuel generating member 19 is further promoted. Therefore, when the state of the exhaust valve 18 is switched from the fully closed state to the fully open state. In addition, when switching instantaneously, the amount of hydrogen discharged from the fuel generator 1 increases rapidly. Therefore, as in the fifth embodiment, it is desirable to gradually increase the opening when switching the state of the exhaust valve 18 from the fully closed state to the fully open state.

  Further, instead of lengthening the switching cycle of the state of the exhaust valve 18 when the demand power is small (for example, the period T shown in FIG. 16), the exhaust valve 18 is exhausted during the period when the state of the exhaust valve 18 is fully open when the demand power is small. The valve 18 is changed to a period in which it is in a half-open state (see FIG. 18). In the opening degree control of the exhaust valve 18 shown in FIG. 18, when the demand power suddenly increases, the period in which the exhaust valve 18 is in the half-open state is returned to the period in which the exhaust valve 18 is in the fully-open state. The amount of hydrogen discharged from the fuel generator 1 can be easily increased. Note that the opening degree in the half-open state may be fixed, may be changed, and may be made smaller as the demand power is smaller.

<Others>
In each embodiment mentioned above, it is also possible to make a specific unit into a stop state at the time of a maintenance by making both the intake valve 16 and the exhaust valve 18 of the fuel generator 1 into a fully closed state. And when putting a specific unit into a stop state, it is possible to continue the operation of the secondary battery type fuel cell system using only the remaining units without stopping the entire secondary battery type fuel cell system. is there.

  Moreover, you may add a non-return valve to the fuel generator 1 used by each embodiment mentioned above. The structure which added the non-return valve 28 to the fuel generator 1 used in 1st Embodiment is shown in FIG.19 and FIG.20. The check valve 28 is provided between the gas inlet 14 of the fuel generator 1 and each unit. By providing the check valve 28, it is possible to prevent the gas from flowing backward from the gas inlet 14 of the fuel generator 1 to the gas outlet side of the fuel cell unit 2. Therefore, the average pressure of the accommodating portion 17 when the opening degree of the exhaust valve 18 is an opening degree corresponding to a fully closed state or an opening degree corresponding to a half-open state is reliably and rapidly increased. Thereby, the generation amount of fuel gas can be increased further.

  In the secondary battery type fuel cell system, the reaction rate between the gas and the fuel generating member 29, the required gas flow rate, and the like differ between the power generation operation of the system and the charging operation of the system. Therefore, the system controller 10 changes the contents of the opening control of the intake valve 16 and the exhaust valve 18 between the system power generation operation and the system charge operation, and the system controller 10 changes between the system power generation operation and the system charge operation. It is desirable that optimum opening degree control is performed in each.

  In each embodiment described above, the number of units is three, but the number of units is not limited to three. Further, the units may be divided into a plurality of groups, and the contents of opening control of the intake valve 16 and the exhaust valve 18 may be made common in the same group. For example, as shown in FIG. 21, six units 11 to 13 and 101 to 103 are provided, the units 11 and 101 are a first group, the units 12 and 102 are a second group, and the units 13 and 103 are a third group. And it is sufficient.

  In each of the embodiments described above, a solid oxide electrolyte is used as the electrolyte membrane 2A of the fuel cell unit 2, and water is generated on the fuel electrode 2B side during power generation. According to this configuration, water is generated on the side where the fuel generating member 1 is provided, which is advantageous for simplification and miniaturization of the apparatus. On the other hand, as a fuel cell disclosed in Japanese Patent Application Laid-Open No. 2009-99491, a solid polymer electrolyte that allows hydrogen ions to pass through may be used as the electrolyte membrane 2A of the fuel cell unit 2. However, in this case, since water is generated on the air electrode 2C side that is the oxidant electrode of the fuel cell unit 2 during power generation, a flow path for propagating this water to the fuel generating member 1 is provided. Just do it. In each of the above-described embodiments, one fuel cell unit 2 performs both power generation and water electrolysis. However, a fuel cell (for example, a solid oxide fuel cell dedicated to power generation) and a water electrolyzer (for example, water) The solid oxide fuel cell dedicated to electrolysis) may be connected to the fuel generating member 1 in parallel on the gas flow path.

  Moreover, in each embodiment mentioned above, although the fuel gas of the fuel cell part 2 is made into hydrogen, you may use reducing gas other than hydrogen, such as carbon monoxide and a hydrocarbon, as fuel gas of the fuel cell part 2. .

  Moreover, in each embodiment mentioned above, although air is used for oxidant gas, you may use oxidant gas other than air.

  Moreover, each embodiment and modification which were mentioned above can be implemented in combination as long as there is no contradiction. For example, it is possible to replace only a part of one embodiment (for example, the state of the exhaust valve 18) with a part of another embodiment (for example, the state of the exhaust valve 18).

  Moreover, in each embodiment mentioned above, although the exhaust valve 18 was switched in two states, you may switch in three or more states.

DESCRIPTION OF SYMBOLS 1 Fuel generator 2 Fuel cell part 2A Electrolyte membrane 2B Fuel electrode 2C Air electrode 3 Heater 4 Container 5, 8, 9 Piping 6 Pump 7 Thermal insulation container 10 System controller 11 1st unit 12 2nd unit 13 3rd unit 14, 24 Gas inlet 15, 25 Gas outlet 16 Intake valve 17 Housing part 18 Exhaust valve 19 Hydrogen generating member 20 Container body 21 Cover body 22 Fuel generating member pellet 23 Stirring part 26 Enlarging chamber 27 Smoothing part 28 Check valve 101-103 unit

Claims (11)

A fuel generator for generating a fuel gas which is a reducing gas by an oxidation reaction with an oxidizing gas,
A gas inlet through which the oxidizing gas is supplied from the outside;
A gas outlet for supplying the fuel gas to the outside;
A fuel generating member that generates the fuel gas by an oxidation reaction with the oxidizing gas;
An accommodating portion that is provided between the gas inlet and the gas outlet and accommodates the fuel generating member;
An intake valve provided between the gas inlet and the accommodating portion;
An exhaust valve provided between the housing portion and the gas outlet,
Comprising a plurality of units constituted by the intake valve, the accommodating portion, and the exhaust valve, and connecting the plurality of units in parallel;
In each of the units, the opening degree of the exhaust valve periodically changes including a first opening degree and a second opening degree smaller than the first opening degree, and the exhaust valve is changed to the first opening degree. When the opening is set, the intake valve is set at a third opening, and when the exhaust valve is set at the second opening, the intake valve is set at a fourth opening larger than the third opening,
The fuel generator according to claim 1, wherein a period during which the exhaust valve is set to the first opening is shifted for each unit.   The fuel generator according to claim 1, wherein an overlapping period between units having different periods in which the opening degree of the exhaust valve is set to the first opening degree can be changed.   The fuel according to claim 1 or 2, wherein an opening of the exhaust valve can change a length of a period that periodically changes including the first opening and the second opening. Generator.   The fuel according to any one of claims 1 to 3, wherein when the opening degree of the exhaust valve is switched from the second opening degree to the first opening degree, the opening degree of the exhaust valve is gradually increased. Generator.   Time taken for the opening of the exhaust valve to switch from the second opening to the first opening when the opening of the exhaust valve is switched from the second opening to the first opening The fuel generator according to claim 4, which can be changed.   The fuel generator according to any one of claims 1 to 5, wherein the first opening degree can be changed.   The length of the period which makes the opening degree of the said exhaust valve the said 1st opening degree is set to the length according to the quantity of the said fuel generation member for every said unit. The fuel generator according to one item.   The fuel generator according to any one of claims 1 to 7, further comprising a gas agitation unit provided between the plurality of units and the gas outlet.   The fuel generator according to any one of claims 1 to 8, further comprising a check valve provided between the gas inlet and the plurality of units. The fuel generator according to any one of claims 1 to 9,
A fuel cell system comprising: a fuel cell device that generates electric power using fuel gas supplied from the fuel generator.   The fuel cell system according to claim 10, further comprising a smoothing unit that smoothes power generated by the fuel cell device.

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