JP7465160B2 - Solid oxide fuel cell generator - Google Patents

Description

The present invention relates to a generator equipped with a solid oxide fuel cell (SOFC).

A solid oxide fuel cell (SOFC) generates electrical energy through an electrochemical reaction between continuously supplied fuel gas (hydrogen ( _H2 ), carbon monoxide (CO)) and oxidizing gas (a mixed gas containing oxygen ( _O2 ) such as air). The fuel cell section that generates electricity has an anode (fuel electrode) and a cathode (air electrode). A fuel gas supply path that supplies fuel gas is connected to the anode. An oxidizing gas supply path that supplies oxidizing gas is connected to the cathode.

Patent Document 1 discloses a power system including a hybrid power generation device including a solid oxide fuel cell and a gas turbine, and a control unit. The gas turbine of the hybrid power generation device described in Patent Document 1 includes a turbine, a compressor, and a generator. The compressor compresses and discharges introduced outside air, and supplies the discharged air to the cathode of the solid oxide fuel cell. The generator starts the gas turbine by functioning as a motor when the gas turbine is started. Thus, in the hybrid power generation device described in Patent Document 1, in order to start supplying air to the cathode of the solid oxide fuel cell and start power generation by the solid oxide fuel cell, an auxiliary power source, i.e., an external power source, is required to drive the compressor for supplying air to the cathode and the generator (motor).

However, in outdoor locations where commercial power is not available or in disaster areas, it may not be possible to secure an auxiliary power source. Therefore, it is desirable for generators equipped with solid oxide fuel cells to be able to start generating the power required to charge electrical appliances such as smartphones and tablet devices, or to use electrical appliances such as LED (Light Emitting Diode) lighting, without needing an auxiliary power source, in outdoor locations where commercial power is not available or in disaster areas.

JP 2009-187756 A

The present invention has been made to solve the above problems, and aims to provide a generator equipped with a solid oxide fuel cell that can start generating electricity without requiring an auxiliary power source, i.e., a solid oxide fuel cell generator.

The object of the present invention is to provide a fuel cell having a solid oxide fuel cell unit which generates electricity using a fuel gas and an oxidizing gas, an oxidizing gas supply unit which sends the oxidizing gas to the fuel cell unit, an oxidizing gas supply path which sends the oxidizing gas sent from the oxidizing gas supply unit to the fuel cell unit, a fuel gas supply path which sends the fuel gas contained in a gas container to the fuel cell unit, heating means which heats the fuel gas guided by the fuel gas supply path, and a thermoelectric power generation unit having a thermoelectric element which generates electricity based on a temperature difference generated between a high temperature portion and a low temperature portion, The above-mentioned problems are solved by the solid oxide fuel cell generator of the present invention, which is characterized in that the fuel cell unit has a configuration in which both the thermoelectric element and the oxidizing gas supply unit are heated, and a control unit executes control to supply the power generated by the thermoelectric element to the oxidizing gas supply unit, the fuel cell unit has a first cell module unit and a second cell module unit, the oxidizing gas supply unit has a first blower that sends the oxidizing gas to the first cell module unit and a second blower that sends the oxidizing gas to the second cell module unit, and the control unit executes control to supply the power generated by the thermoelectric element only to the first blower.

According to the solid oxide fuel cell generator of the present invention, the heating means uses the fuel gas introduced through the fuel gas supply path to heat the fuel cell section to a power generation start temperature. The thermoelectric generation section has a thermoelectric element that is heated by the heating means and generates power based on a temperature difference between a high temperature section and a low temperature section. The control section executes control to supply the electric power generated by the thermoelectric element of the thermoelectric generation section to the oxidizing gas supply section. Therefore, the oxidizing gas supply section can start operating by being supplied with the electric power generated by the thermoelectric element of the thermoelectric generation section heated by the heating means, without requiring an auxiliary power source such as a battery, and can supply the oxidizing gas to the fuel cell section through the oxidizing gas supply path. Thus, the fuel cell section can start generating power using the fuel gas supplied from the gas container through the fuel gas supply path and the oxidizing gas supplied from the oxidizing gas supply section through the oxidizing gas supply path, without requiring an auxiliary power source such as a battery. Furthermore, since an auxiliary power source is not required, the solid oxide fuel cell generator can be made smaller in size.
Furthermore, in the solid oxide fuel cell generator according to the present invention, the control unit executes control to supply the electric power generated by the thermoelectric element of the thermoelectric power generation unit only to the first blower among the multiple blowers of the oxidizing gas supply unit. The first blower starts to operate when supplied with the electric power generated by the thermoelectric element of the thermoelectric power generation unit, and supplies the oxidizing gas to the first cell module unit among the multiple cell module units of the fuel cell unit. In this way, the control unit executes control to supply the electric power generated by the thermoelectric element of the thermoelectric power generation unit only to the first blower, not to all of the multiple blowers of the oxidizing gas supply unit. Therefore, immediately after the thermoelectric element of the thermoelectric power generation unit starts generating electric power, the oxidizing gas is not supplied to all of the multiple cell module units of the fuel cell unit, but is supplied to the first cell module unit. The first cell module unit to which the oxidizing gas is supplied starts generating electric power. Therefore, the fuel cell unit having multiple cell module units can start generating electric power for each cell module unit to which the supply of oxidizing gas has started, that is, in a stepwise manner. This allows the power generated in the first cell module unit to be used in advance before all the cell module units start generating electricity. Furthermore, when the first cell module unit starts generating electricity, it generates heat by itself. The heat generated by the self-heating of the first cell module unit can be effectively used to heat the second cell module unit. This allows the startup time or operation start time (i.e., start-up time) required for the fuel cell unit to start generating electricity to be shortened compared to when all the cell module units are heated simultaneously only by the heating means. Furthermore, the flow rate of the oxidizing gas and the amount of heat of the heating means required for the fuel cell unit to start generating electricity can be reduced. This allows the oxidizing gas supply unit and the heating means to be miniaturized, and the solid oxide fuel cell generator to be miniaturized.

In the solid oxide fuel cell generator according to the present invention, preferably, the first cell module generates electricity using the oxidizing gas supplied from the first blower through the oxidizing gas supply path and the fuel gas supplied through the fuel gas supply path, and the control unit executes control to supply the electricity generated by the first cell module to the second blower.

According to the solid oxide fuel cell generator of the present invention, the first cell module unit starts generating electricity with the oxidizing gas supplied from the first blower through the oxidizing gas supply path and the fuel gas supplied through the fuel gas supply path. The control unit then executes control to supply the power generated by the first cell module unit that has started generating electricity to the second blower. The second blower then starts operating by being supplied with the power generated by the first cell module unit that has started generating electricity, and supplies the oxidizing gas to the second cell module unit. In this way, the control unit supplies the power generated by the thermoelectric element of the thermoelectric generation unit only to the first blower to start generating electricity for the first cell module unit, and supplies the power generated by the first cell module unit that has started generating electricity to the second blower to start generating electricity for the second cell module unit. Therefore, the fuel cell unit having multiple cell module units can start generating electricity for each cell module unit that has started receiving the supply of oxidizing gas, that is, in a stepwise manner. This makes it possible to shorten the startup time or operation start time (i.e., start-up time) until the fuel cell unit starts generating electricity. In addition, the flow rate of oxidizing gas and the amount of heat of the heating means required for the fuel cell unit to start generating electricity can be reduced. This allows the oxidizing gas supply unit and heating means to be miniaturized, and the solid oxide fuel cell generator to be miniaturized.

In the solid oxide fuel cell generator according to the present invention, preferably, the second cell module section is further heated by heat generated by the power generation of the first cell module section, and generates power using the oxidizing gas supplied from the second blower through the oxidizing gas supply passage and the fuel gas supplied through the fuel gas supply passage.

According to the solid oxide fuel cell generator of the present invention, the second cell module section is further heated by heat generated by the power generation of the first cell module section, i.e., heat due to the self-heating of the first cell module section. In other words, the second cell module section is heated by both the heating means and the first cell module section. This makes it possible to further shorten the startup time or operation start time (i.e., start-up time) until the fuel cell section starts generating electricity. Therefore, it is possible to further reduce the flow rate of oxidizing gas and the amount of heat of the heating means required for the fuel cell section to start generating electricity. This makes it possible to further miniaturize the oxidizing gas supply section and the heating means, and thus to further miniaturize the solid oxide fuel cell generator.

In the solid oxide fuel cell generator of the present invention, preferably, the heating means is a burner that burns the fuel gas guided by the fuel gas supply path, and the thermoelectric power generation unit is heated by heat transmitted from the flame emitted from the burner, and the high-temperature portion of the thermoelectric power generation unit is arranged opposite the fuel cell unit, so that the thermoelectric power generation unit is heated by heat generated by power generation of the fuel cell unit due to the effect of thermal conduction .

According to the solid oxide fuel cell generator of the present invention, the burner as a heating means burns the fuel gas introduced by the fuel gas supply passage. The thermoelectric power generation unit is heated by the flame emitted from the burner and the heat transferred from the exhaust gas. Therefore, the waste heat from the combustion of the burner, i.e., unused thermal energy, can be used not only to increase the temperature of the fuel cell unit, but also to increase the temperature of the high-temperature part of the thermoelectric power generation unit. This can improve the efficiency of fuel gas utilization. Even if the burner stops burning, the fuel cell unit can maintain a high temperature when it starts generating power due to self-heating caused by power generation. The thermoelectric power generation unit is also heated by the heat generated by the power generation of the fuel cell unit, i.e., the heat generated by the self-heating of the fuel cell unit. Therefore, the thermoelectric power generation unit can continue to generate power by the thermoelectric element by utilizing the heat generated by the power generation of the fuel cell unit. This can effectively utilize the heat generated by the power generation of the fuel cell unit.

The present invention provides a generator equipped with a solid oxide fuel cell that can start generating electricity without requiring an auxiliary power source, i.e., a solid oxide fuel cell generator.

1 is a perspective view showing a solid oxide fuel cell generator according to an embodiment of the present invention; 1 is a block diagram showing the configuration of a main part of a solid oxide fuel cell generator according to an embodiment of the present invention. FIG. 2 is a block diagram for explaining an outline of the operation of the solid oxide fuel cell generator according to the present embodiment. 4 is a flowchart showing a specific example of the operation of the solid oxide fuel cell generator according to the present embodiment. 4 is a timing chart showing a specific example of the operation of the solid oxide fuel cell generator according to the present embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
The embodiments described below are preferred specific examples of the present invention, and therefore various technically preferable limitations are applied to them, but the scope of the present invention is not limited to these aspects unless otherwise specified in the following description to the effect that the present invention is limited to them. In addition, in each drawing, similar components are given the same reference numerals, and detailed descriptions thereof are omitted as appropriate.

FIG. 1 is a perspective view showing a solid oxide fuel cell generator according to an embodiment of the present invention.
FIG. 2 is a block diagram showing the configuration of the main parts of the solid oxide fuel cell generator according to this embodiment.
FIG. 3 is a block diagram for explaining an outline of the operation of the solid oxide fuel cell generator according to this embodiment.

The solid oxide fuel cell generator 11 according to this embodiment is a generator that uses a gas container 12 filled with a fuel gas (hydrocarbon fuel) such as butane gas, and can be moved to a location where electricity is needed at various times to generate electricity. In other words, the solid oxide fuel cell generator 11 according to this embodiment is a portable generator that uses the fuel gas stored in the gas container 12 and can be used outdoors where commercial power is not available, or at disaster sites.

As shown in Figures 1 to 3, the solid oxide fuel cell generator 11 according to this embodiment includes a fuel cell section 26, an oxidizing gas supply section 21, an oxidizing gas supply path 16, a fuel gas supply path 15, a burner 17, a thermoelectric power generation section 61, and a control section 58. As shown in Figure 1, the fuel cell section 26, the oxidizing gas supply section 21, the burner 17, the thermoelectric power generation section 61, and the control section 58 are provided in a housing 63.

The fuel cell unit 26 is a solid oxide fuel cell unit that generates power from a fuel gas and an oxidizing gas. That is, the fuel cell unit 26 has a solid oxide fuel cell (SOFC) that generates electrical energy by an electrochemical reaction between a fuel gas (hydrogen ( _H2 ) and carbon monoxide (CO)) and an oxidizing gas (a mixed gas containing oxygen ( _O2 ) such as air).

The fuel cell section 26 has multiple cell modules. As shown in FIG. 1, the fuel cell section 26 of this embodiment has a first cell module 27a, a second cell module 27b, a third cell module 27c, and a fourth cell module 27d. The cell modules are also called cell stacks. The number of cell modules in the fuel cell section 26 is not limited to four, and may be three or less, or five or more. In the explanation of this embodiment, a case in which the fuel cell section 26 has four cell modules 27a, 27b, 27c, and 27d is given as an example.

2, each of the cell modules 27a, 27b, 27c, and 27d has a plurality of cells 13 as the minimum unit of the fuel cell section 26. The cells 13 of the fuel cell section 26 have an anode (fuel electrode) 13a where an oxidation reaction occurs, a cathode (air electrode) 13b where a reduction reaction occurs, and an electrolyte 13c which is an ion conductor. The anode 13a is connected to a fuel gas supply path 15. The cathode 13b is connected to an oxidizing gas supply path 16. In the anode 13a, at least one of hydrogen (H ₂ ) and carbon monoxide (CO) is used as a fuel. In the cathode 13b, air (oxygen) is used as an oxidizing agent.

The oxidizing gas supply unit 21 is connected to the oxidizing gas supply path 16 and sends oxidizing gas to the cathode 13b of the fuel cell unit 26 through the oxidizing gas supply path 16. The oxidizing gas supply unit 21 has multiple blowers. As shown in FIG. 3, the oxidizing gas supply unit 21 of this embodiment has a first blower 21a and a second blower 21b. Examples of the first blower 21a and the second blower 21b include an air pump and a fan. The number of blowers that the oxidizing gas supply unit 21 has is not limited to two, and may be one, or three or more.

As shown in FIG. 3, the first blower 21a sends oxidizing gas to the first cell module section 26a of the fuel cell section 26. The second blower 21b sends oxidizing gas to the second cell module section 26b of the fuel cell section 26. In this specification, the "cell module section" refers to an assembly of one or more cell modules (in other words, a cell stack). For example, the first cell module section 26a may include only the first cell module 27a, may include the first cell module 27a and the second cell module 27b, or may include the first cell module 27a, the second cell module 27b, and the third cell module 27c. Also, for example, the second cell module section 26b may include the second cell module 27b, the third cell module 27c, and the fourth cell module 27d, may include the third cell module 27c and the fourth cell module 27d, or may include only the fourth cell module 27d. Specific examples of the first cell module unit 26a and the second cell module unit 26b will be described later.

The oxidizing gas supply path 16 is a flow path connected to the oxidizing gas supply unit 21 and the cathode 13b of the fuel cell unit 26, and guides the oxidizing gas sent from the oxidizing gas supply unit 21 to the cathode 13b of the fuel cell unit 26.

The gas container 12 is, for example, a cartridge-type gas cylinder that contains compressed liquefied gas, and contains fuel gas. The fuel gas discharged from the gas container 12 enters a governor provided inside the container connection part 64 (see FIG. 1) and is pressure-regulated. When the gas container 12 is a cartridge-type gas cylinder, the attachment/detachment mechanism between the gas container 12 and the container connection part 64 is a magnetic type. With this, when the gas cylinder is heated and the internal pressure of the gas cylinder rises abnormally, a safety mechanism is activated and the connection between the gas container 12 and the container connection part 64 is released.

The fuel gas supply passage 15 is a flow path connected to the container connection portion 64 and the anode 13a of the fuel cell portion 26, and guides fuel gas such as butane gas filled in the gas container 12 to the anode 13a of the fuel cell portion 26. Specifically, as shown in FIG. 2, the fuel gas supply passage 15 guides the fuel gas to the anode 13a via the reformer 14. Note that the reformer 14 does not necessarily have to be provided. The solid oxide fuel cell generator 11 shown in FIG. 2 is an example of a generator in which the reformer 14 is provided as an auxiliary facility.

The reformer 14 has a reforming catalyst, and reforms the fuel gas into hydrogen (H ₂ ) and carbon monoxide (CO), etc., and then supplies the hydrogen (H ₂ ) and carbon monoxide (CO) to the fuel cell unit 26. For example, the reformer 14 reforms the fuel gas by a partial oxidation reaction. Partial oxidation is a reaction in which a part of a hydrocarbon is burned with oxygen or air to produce a mixed gas of hydrogen and carbon monoxide. The reforming catalyst of the reformer 14 is heated to, for example, about 300° C. to cause a partial oxidation reaction. When the partial oxidation reaction occurs, the reforming catalyst of the reformer 14 reaches, for example, about 700° C. A reforming air supply passage 24 is provided so that the reforming catalyst of the reformer 14 causes a partial oxidation reaction. For example, as shown in FIG. 2, the reforming air supply passage 24 branches off from the oxidizing gas supply passage 16, and guides the oxidizing gas sent from the oxidizing gas supply unit 21 to the reformer 14. The means for supplying air to the reformer 14 is not limited to the oxidizing gas supply unit 21, and may be other means. In addition, as long as air can be supplied to the reformer 14, the reforming air supply path 24 does not necessarily have to be branched off from the oxidizing gas supply path 16.

The burner 17 burns the fuel gas (hydrocarbon fuel) supplied from the gas container 12 through the fuel gas supply line 15 to heat the fuel cell section 26 to the power generation start temperature. Specifically, as shown in FIG. 2, the burner fuel supply line 22 branches off from the fuel gas supply line 15 and is connected to the burner 17. The fuel gas supplied from the gas container 12 through the container connection part 64 passes through the fuel gas supply line 15, the burner fuel supply line 22, and a gas-air mixer (not shown), and is introduced to the burner 17 while being mixed with air.

An electrode (not shown) is provided near the burner 17. When a user rotates the operating knob (not shown), an igniter (not shown) is pressed, generating a pulse voltage. The electrode provided near the burner 17 discharges due to the pulse voltage generated by the rotation of the operating knob, combusting the fuel gas supplied to the burner 17 from the gas container 12 and igniting the burner 17. The burner 17 of this embodiment is an example of the "heating means" of the present invention.

The thermoelectric power generation unit 61 has a high temperature section 61a, a low temperature section 61b, and a thermoelectric element 61c, and is heated by the burner 17. Specifically, the high temperature section 61a is provided, for example, opposite the fuel cell section 26, and is heated by heat transmitted from the flame and exhaust gas emitted from the burner 17. The high temperature section 61a functions as a heat receiving section, efficiently receiving heat transmitted from the flame and exhaust gas emitted from the burner 17 and transmitting it to the thermoelectric element 61c. The low temperature section 61b is provided away from the high temperature section 61a via the thermoelectric element 61c. The low temperature section 61b is disposed opposite the high temperature section 61a, and is maintained at a lower temperature than the high temperature section 61a. The cooling method of the low temperature section 61b is not particularly limited, and may be, for example, a natural air cooling method or a forced air cooling method.

The thermoelectric element 61c is sandwiched between the high temperature section 61a and the low temperature section 61b, and generates electricity based on the temperature difference between the high temperature section 61a and the low temperature section 61b. The thermoelectric element 61c generates thermoelectromotive force by utilizing the Seebeck effect. Thermoelectric elements are also called thermoelectric conversion elements or thermoelectric generation elements. The thermoelectric element 61c can generate more thermoelectromotive force when the temperature difference between the high temperature section 61a and the low temperature section 61b is, for example, about 100°C to 150°C.

As shown in FIG. 2, the exhaust path 19 is connected to the fuel cell section 26. The exhaust path 19 is a flow path that discharges high-temperature exhaust gas discharged from the fuel cell section 26 to the outside of the solid oxide fuel cell generator 11. A CO remover 18 is provided in the exhaust path 19. The CO remover 18 uses a catalyst provided inside to remove CO from exhaust gas at a temperature of 200°C or higher.

2, a heat exchanger 23 is provided in the oxidizing gas supply path 16 and the exhaust path 19. The heat exchanger 23 exchanges heat between the oxidizing gas supply path 16 and the exhaust path 19. In the solid oxide fuel cell generator 11 according to this embodiment, two heat exchangers 23, namely, a low-temperature side heat exchanger 23a and a high-temperature side heat exchanger 23b, are provided.

The oxidizing gas sent from the oxidizing gas supply unit 21 to the oxidizing gas supply path 16 passes through the low-temperature side heat exchanger 23a, where it exchanges heat with the exhaust gas flowing through the exhaust path 19 in the low-temperature side heat exchanger 23a, and is heated. Next, the oxidizing gas that has passed through the low-temperature side heat exchanger 23a passes through the high-temperature side heat exchanger 23b, where it exchanges heat with the exhaust gas flowing through the exhaust path 19 in the high-temperature side heat exchanger 23b, and is further heated. The oxidizing gas that has passed through the low-temperature side heat exchanger 23a and the high-temperature side heat exchanger 23b and has become hot is then guided through the oxidizing gas supply path 16 to the cathode 13b of the fuel cell unit 26.

The high-temperature exhaust gas generated by power generation in the fuel cell section 26 passes through the high-temperature side heat exchanger 23b and exchanges heat with the oxidizing gas flowing through the oxidizing gas supply path 16 in the high-temperature side heat exchanger 23b to lower its temperature. The temperature of the exhaust gas discharged from the fuel cell section 26 before passing through the high-temperature side heat exchanger 23b is, for example, about 600°C or higher. The temperature of the exhaust gas that has passed through the high-temperature side heat exchanger 23b and has been lowered is, for example, about 200°C or higher. This allows the catalyst in the CO remover 18 to act more reliably on the exhaust gas. Next, the exhaust gas that has passed through the high-temperature side heat exchanger 23b passes through the CO remover 18 and the low-temperature side heat exchanger 23a and exchanges heat with the oxidizing gas flowing through the oxidizing gas supply path 16 in the low-temperature side heat exchanger 23a to further lower its temperature. The temperature of the exhaust gas that has passed through the low-temperature side heat exchanger 23a and has been lowered is, for example, less than about 80°C. The exhaust gas, which has passed through the high-temperature side heat exchanger 23b and the low-temperature side heat exchanger 23a and has become cold, is discharged from the outlet of the exhaust path 19.

The control unit 58 controls the overall operation of the solid oxide fuel cell generator 11 according to this embodiment. For example, as shown in FIG. 2 and FIG. 3, the control unit 58 receives the power generated by the fuel cell unit 26 and the thermoelectric power generation unit 61 and supplies it to the oxidizing gas supply unit 21. Details of this will be described later. The control unit 58 also has a power conversion device 54. The power conversion device 54 receives the power generated by the fuel cell unit 26 and converts the DC power into AC power.

As described above, the fuel cell unit 26 generates electricity through an electrochemical reaction between the fuel gas and the oxidizing gas. Therefore, in order for the fuel cell unit 26 to start generating electricity, it is necessary to start supplying oxidizing gas to the cathode 13b of the fuel cell unit 26. In that case, it may be necessary to start driving the oxidizing gas supply unit 21, which sends oxidizing gas to the cathode 13b of the fuel cell unit 26, using an auxiliary power source (i.e., an external power source) such as a battery. However, in outdoor locations where commercial power is not available or at disaster sites, it may not be possible to secure an auxiliary power source.

In contrast, the solid oxide fuel cell generator 11 according to the present invention includes a thermoelectric power generation unit 61. As described above, the thermoelectric power generation unit 61 has a thermoelectric element 61c and is heated by the burner 17. The thermoelectric element 61c generates electricity based on the temperature difference between the high temperature portion 61a and the low temperature portion 61b. The control unit 58 receives the electric power generated by the thermoelectric element 61c of the thermoelectric power generation unit 61 and controls the supply of the electric power to the oxidizing gas supply unit 21.

According to the solid oxide fuel cell generator 11 of this embodiment, the oxidizing gas supply unit 21 can start operating by being supplied with power generated by the thermoelectric element 61c of the thermoelectric generation unit 61 heated by the burner 17 without requiring an auxiliary power source such as a battery, and can supply oxidizing gas to the fuel cell unit 26 through the oxidizing gas supply path 16. As a result, the fuel cell unit 26 can start generating electricity using the fuel gas supplied from the gas container 12 through the fuel gas supply path 15 and the oxidizing gas supplied from the oxidizing gas supply unit 21 through the oxidizing gas supply path 16, without requiring an auxiliary power source such as a battery. In addition, since an auxiliary power source is no longer required, the solid oxide fuel cell generator 11 can be made smaller.

In addition, the solid oxide fuel cell generator 11 according to this embodiment can combine power generation by the fuel cell section 26 and power generation by the thermoelectric power generation section 61. In other words, part of the required power generated by the high-temperature operation of the fuel cell section 26 can be supplemented with power generated by the thermoelectric element 61c of the thermoelectric power generation section 61. Therefore, compared to the case where the fuel cell section 26 generates the same amount of power alone, the total power generation amount of the solid oxide fuel cell generator 11 can be increased by the auxiliary amount of the power generated by the thermoelectric element 61c of the thermoelectric power generation section 61, and the amount of fuel gas used can be reduced and fuel gas can be saved. In addition, compared to the case where the fuel cell section 26 generates power alone, the operating temperature of the fuel cell section 26 can be stably maintained at about 650±50°C. This can improve the durability of the fuel cell section 26 and suppress the thermal impact on the peripheral devices of the fuel cell section 26. This can also widen the range of materials that can be used for the peripheral devices of the fuel cell section 26.

Next, a specific example of the operation of the solid oxide fuel cell generator 11 according to this embodiment will be described with reference to the drawings.
FIG. 4 is a flow chart showing a specific example of the operation of the solid oxide fuel cell generator according to this embodiment.
FIG. 5 is a timing chart showing a specific example of the operation of the solid oxide fuel cell generator according to this embodiment.

First, the user turns the operating knob (not shown), for example, to ignite the burner 17. Then, the burner 17 starts burning the fuel gas supplied from the gas container 12 through the fuel gas supply passage 15, heating the fuel cell section 26 and the thermoelectric power generation section 61 (step S11 in FIG. 4, timing T11 in FIG. 5). Then, when a temperature difference occurs between the high temperature section 61a and the low temperature section 61b due to the flame emitted from the burner 17 and the heat transmitted from the exhaust gas, the thermoelectric element 61c of the thermoelectric power generation section 61 starts generating electricity (step S12 in FIG. 4, timing T11 to timing T12 in FIG. 5). Then, the control section 58 receives the electricity generated by the thermoelectric element 61c of the thermoelectric power generation section 61 and supplies it only to the first blower 21a (step S13 in FIG. 4).

Then, the first blower 21a starts to operate by receiving power generated by the thermoelectric element 61c of the thermoelectric power generation unit 61 from the control unit 58, and supplies oxidizing gas to the first cell module unit 26a (step S14 in FIG. 4, timing T12 in FIG. 5). In this specific example, as an example, the first cell module unit 26a includes only the first cell module 27a, and the second cell module unit 26b includes the second cell module 27b, the third cell module 27c, and the fourth cell module 27d. Therefore, in this specific example, the first blower 21a starts to operate by receiving power generated by the thermoelectric element 61c of the thermoelectric power generation unit 61 from the control unit 58, and supplies oxidizing gas to the first cell module 27a.

Next, when the first cell module part 26a (in this specific example, the first cell module 27a) is heated to the power generation start temperature, it starts power generation using the oxidizing gas supplied from the first blower 21a through the oxidizing gas supply path 16 and the fuel gas supplied from the gas container 12 through the fuel gas supply path 15 (step S15 in FIG. 4, timing T13 in FIG. 5). At this time, heat is generated in the first cell module part 26a due to the power generation of the first cell module part 26a. In other words, when the first cell module part 26a starts power generation, it generates its own heat due to power generation. Next, the control unit 58 receives the power generated by the first cell module part 26a and supplies it to the second blower 21b (step S16 in FIG. 4).

Then, the second blower 21b starts to operate by receiving the power generated by the first cell module part 26a from the control unit 58, and supplies oxidizing gas to the second cell module part 26b (in this specific example, the second cell module 27b, the third cell module 27c, and the fourth cell module 27d) (step S17 in FIG. 4, timing T14 in FIG. 5). At this time, the second cell module part 26b is further heated by the heat generated by the power generation of the first cell module part 26a, that is, the heat due to the self-heating of the first cell module part 26a. In other words, the second cell module part 26b is heated by both the burner 17 and the first cell module part 26a. Next, when the second cell module part 26b is heated to the power generation start temperature, it starts power generation with the oxidizing gas supplied from the second blower 21b through the oxidizing gas supply path 16 and the fuel gas supplied from the gas container 12 through the fuel gas supply path 15 (step S18 in FIG. 4, timing T15 in FIG. 5). At this time, heat is generated in the second cell module section 26b due to the power generation of the second cell module section 26b. In other words, the second cell module section 26b, like the first cell module section 26a, generates heat by itself when it starts generating power. In this way, all the cell modules 27a, 27b, 27c, and 27d of the fuel cell section 26 start generating power.

Then, when the user turns, for example, an operating knob (not shown), the burner 17 stops burning (step S19 in FIG. 4, timing T16 in FIG. 5). Even after the burner 17 stops burning, the first cell module unit 26a and the second cell module unit 26b can maintain a high temperature of, for example, 600°C or higher due to self-heating, and can continue generating electricity until the supply of fuel gas is stopped (timings T16 to T17 in FIG. 5). Examples of when the supply of fuel gas is stopped include when the supply of fuel gas is intentionally stopped using a valve or when the supply of fuel gas is stopped due to the fuel gas in the gas container 12 being used up.

The thermoelectric element 61c of the thermoelectric power generation unit 61 can continue generating electricity based on the temperature difference generated between the high temperature section 61a and the low temperature section 61b (timing T16 to timing T17 in FIG. 5). This allows the first blower 21a to continue supplying oxidizing gas to the first cell module section 26a (timing T16 to timing T17 in FIG. 5). This also allows the second blower 21b to continue supplying oxidizing gas to the second cell module section 26b (timing T16 to timing T17 in FIG. 5).

When the supply of fuel gas is stopped, the power generation of the first cell module unit 26a and the second cell module unit 26b is stopped, and the operation of the second fan 21b is stopped (timing T17 in FIG. 5). When the temperature difference between the high temperature section 61a and the low temperature section 61b becomes equal to or lower than a predetermined temperature, the thermoelectromotive force generated by the thermoelectric element 61c of the thermoelectric generation unit 61 gradually decreases (timings T17 to T18 in FIG. 5). When the power generation of the thermoelectric element 61c of the thermoelectric generation unit 61 is stopped, the operation of the first fan 21a is stopped (timing T18 in FIG. 5).

According to a specific example of the operation of the solid oxide fuel cell generator 11 according to this embodiment, the control unit 58 executes control to supply the electric power generated by the thermoelectric element 61c of the thermoelectric generation unit 61 only to the first blower 21a, not to all of the multiple blowers 21a and 21b of the oxidizing gas supply unit 21. Therefore, immediately after the thermoelectric element 61c of the thermoelectric generation unit 61 starts generating electric power, the oxidizing gas is not supplied to all of the multiple cell module parts 26a and 26b of the fuel cell unit 26, but is supplied to the first cell module part 26a. Then, the first cell module part 26a to which the oxidizing gas is supplied starts generating electric power. Therefore, the fuel cell unit 26 having the multiple cell module parts 26a and 26b can start generating electric power for each cell module part to which the supply of the oxidizing gas is started, that is, in a stepwise manner. This allows the electric power generated in the first cell module part 26a to be used in advance before all the cell module parts 26a and 26b start generating electric power. In addition, the first cell module section 26a generates heat when it starts generating electricity. The heat generated by the first cell module section 26a can be effectively used to heat the second cell module section 26b. This shortens the startup time or operation start time (i.e., start-up time) required for the fuel cell section 26 to start generating electricity compared to when all the cell module sections 26a, 26b are heated simultaneously only by the burner 17. In addition, the flow rate of the oxidizing gas and the amount of heat of the burner 17 required for the fuel cell section 26 to start generating electricity can be reduced. This allows the oxidizing gas supply section 21 and the burner 17 to be made smaller, and the solid oxide fuel cell generator 11 to be made smaller.

The control unit 58 also supplies the power generated by the thermoelectric element 61c of the thermoelectric power generation unit 61 only to the first blower 21a to start power generation in the first cell module unit 26a, and supplies the power generated by the first cell module unit 26a that has started power generation to the second blower 21b to start power generation in the second cell module unit 26b. Therefore, as described above, the fuel cell unit 26 having multiple cell module units 26a, 26b can start power generation for each cell module unit that has started receiving oxidizing gas, that is, in a stepwise manner. This provides the same effects as those described above.

The second cell module section 26b is further heated by heat generated by the power generation of the first cell module section 26a, i.e., heat generated by the self-heating of the first cell module section 26a. In other words, the second cell module section 26b is heated by both the burner 17 and the first cell module section 26a. This makes it possible to further shorten the startup time or operation start time (i.e., start-up time) until the fuel cell section 26 starts generating power. Therefore, the flow rate of oxidizing gas and the amount of heat of the burner 17 required for the fuel cell section 26 to start generating power can be further reduced. This makes it possible to further miniaturize the oxidizing gas supply section 21 and the burner 17, and further miniaturize the solid oxide fuel cell generator 11.

As described above, the thermoelectric power generation unit 61 is heated by the flame emitted from the burner 17 and the heat transmitted from the exhaust gas. Therefore, the waste heat from the combustion of the burner 17, i.e., unused thermal energy, can be used not only to increase the temperature of the fuel cell unit 26, but also to increase the temperature of the high-temperature part 61a of the thermoelectric power generation unit 61. This can improve the efficiency of fuel gas utilization. Even if the burner 17 stops burning, the fuel cell unit 26 can maintain a high temperature by self-heating due to power generation when power generation is started. The thermoelectric power generation unit 61 is also heated by the heat generated by the power generation of the fuel cell unit 26, i.e., the heat generated by the self-heating of the fuel cell unit 26. Therefore, the thermoelectric power generation unit 61 can continue to generate power by the thermoelectric element 61c by utilizing the heat generated by the power generation of the fuel cell unit 26. This can effectively utilize the heat generated by the power generation of the fuel cell unit 26.

In this specific example, the first cell module portion 26a includes only the first cell module 27a, and the second cell module portion 26b includes the second cell module 27b, the third cell module 27c, and the fourth cell module 27d. However, the pattern of the cell modules included in each of the first cell module portion 26a and the second cell module portion 26b is not limited to this. For example, the first cell module portion 26a may include the first cell module 27a and the second cell module portion 26b, and the second cell module portion 26b may include the third cell module 27c and the fourth cell module 27d.

In this case, the control unit 58 receives the electric power generated by the thermoelectric element 61c of the thermoelectric generating unit 61 and supplies it only to the first blower 21a (step S13 in FIG. 4). Then, the first blower 21a starts operating by receiving the electric power generated by the thermoelectric element 61c of the thermoelectric generating unit 61 from the control unit 58, and supplies oxidizing gas to the first cell module 27a and the second cell module 27b (step S14 in FIG. 4, timing T12 in FIG. 5). When the first cell module 27a and the second cell module 27b are heated to the power generation start temperature, they start generating electricity using the oxidizing gas supplied from the first blower 21a through the oxidizing gas supply path 16 and the fuel gas supplied from the gas container 12 through the fuel gas supply path 15 (step S15 in FIG. 4, timing T13 in FIG. 5). Then, the second blower 21b starts to operate by receiving the power generated by the first cell module 27a and the second cell module 27b from the control unit 58, and supplies oxidizing gas to the third cell module 27c and the fourth cell module 27d (step S17 in FIG. 4, timing T14 in FIG. 5). When the third cell module 27c and the fourth cell module 27d are heated to the power generation start temperature, power generation is started using the oxidizing gas supplied from the second blower 21b through the oxidizing gas supply path 16 and the fuel gas supplied from the gas container 12 through the fuel gas supply path 15 (step S18 in FIG. 4, timing T15 in FIG. 5). Even in this case, the same effect as that described above for this specific example can be obtained.

The above describes an embodiment of the present invention. However, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the claims. The configurations of the above embodiment can be partially omitted or arbitrarily combined in a different way than described above.

11: solid oxide fuel cell generator, 12: gas container, 13: cell, 13a: anode, 13b: cathode, 13c: electrolyte, 14: reformer, 15: fuel gas supply path, 16: oxidizing gas supply path, 17: burner, 18: CO remover, 19: exhaust path, 21: oxidizing gas supply section, 21a: first blower, 21b: second blower, 22: burner fuel supply path, 23: heat exchanger, 23a: low temperature side heat exchanger, 23b: high temperature side heat exchanger, 24: reforming air supply path, 26: fuel cell section, 26a: first cell module section, 26b: second cell module section, 27a: first cell module, 27b: second cell module, 27c: third cell module, 27d: fourth cell module, 54: Power conversion device, 58: Control unit, 61: Thermoelectric power generation unit, 61a: High temperature unit, 61b: Low temperature unit, 61c: Thermoelectric element, 63: Housing, 64: Container connection unit

Claims (4)

a solid oxide fuel cell unit that generates electricity using a fuel gas and an oxidizing gas;
an oxidizing gas supply unit for supplying the oxidizing gas to the fuel cell unit;
an oxidizing gas supply passage for introducing the oxidizing gas sent from the oxidizing gas supply unit to the fuel cell unit;
a fuel gas supply passage for introducing the fuel gas contained in a gas container into the fuel cell unit;
a heating means for heating the fuel gas guided through the fuel gas supply passage;
a thermoelectric power generation unit having a thermoelectric element that generates power based on a temperature difference generated between a high-temperature portion and a low-temperature portion,
the heating means is configured to heat both the fuel cell unit and the thermoelectric power generation unit,
a control unit that controls the supply of power generated by the thermoelectric element to the oxidizing gas supply unit,
the fuel cell section has a first cell module section and a second cell module section,
the oxidizing gas supply unit includes a first blower that supplies the oxidizing gas to the first cell module unit and a second blower that supplies the oxidizing gas to the second cell module unit;
The solid oxide fuel cell generator, wherein the control unit executes control to supply the electric power generated by the thermoelectric element only to the first blower. the first cell module unit generates power using the oxidant gas supplied from the first blower through the oxidant gas supply channel and the fuel gas supplied through the fuel gas supply channel;
2. The solid oxide fuel cell generator according to claim 1, wherein the control unit executes control to supply the electric power generated by the first cell module unit to the second blower. The solid oxide fuel cell generator according to claim 2, characterized in that the second cell module section is further heated by heat generated by the power generation of the first cell module section, and generates power using the oxidizing gas supplied from the second blower through the oxidizing gas supply path and the fuel gas supplied through the fuel gas supply path. the heating means is a burner that burns the fuel gas introduced through the fuel gas supply passage,
The solid oxide fuel cell generator according to any one of claims 1 to 3, characterized in that the thermoelectric power generation unit is heated by heat transmitted from the flame emitted from the burner, and the high-temperature portion of the thermoelectric power generation unit is disposed opposite the fuel cell unit, so that the thermoelectric power generation unit is heated by heat generated by power generation in the fuel cell unit due to the effect of thermal conduction.

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