Fuel cell system

Abstract

The present invention relates to a fuel cell which sufficiently suppresses heat dissipation to the outside of a case and further improves power generation efficiency. A fuel cell system is provided with a fuel cell, a combustion unit, a plurality of heat exchange units, and a heat-insulating case that houses the fuel cell, the combustion unit, and the heat exchange units. Each of the plurality of heat exchange units has a low-temperature gas flow path through which a low-temperature gas, which is a fuel gas or an oxidant gas supplied to the fuel cell, flows, and a high-temperature gas flow path through which a high-temperature gas, which is an exhaust gas discharged from the fuel cell or a combustion exhaust gas discharged from the combustion unit, flows. And the low-temperature gas and the high-temperature gas are subjected to heat exchange. The fuel cell and the combustion unit are disposed in the center of the internal space of the case, and one or more heat exchange units among the plurality of heat exchange units are disposed so as to cover at least a part of the fuel cell and the combustion unit from the outside.

Description

Technical Field

[0001] This invention relates to a fuel cell system. Background Technology

[0002] Conventionally, a fuel cell device has been proposed, comprising: a fuel cell that generates electricity using reformed gas and power generation air; a burner that combusts the exhaust gas from the reformed gas discharged from the fuel cell and the exhaust air for power generation; a first air heat exchanger having a combustion exhaust gas path through which combustion exhaust gas generated by the burner flows and a first air supply path through which power generation air flows, and exchanging heat between the combustion exhaust gas and the power generation air; a fuel cell housing that houses the fuel cell and allows the exhaust air for power generation discharged from the fuel cell to flow; a second air heat exchanger having a second air supply path that supplies power generation air flowing in the first air supply path to the fuel cell, and exchanging heat between the exhaust air for power generation flowing within the fuel cell housing and the power generation air flowing in the second air supply path; and a frame that houses the components, wherein the first air supply path and the second air supply path are configured to cover the entire component assembly housed inside the frame (for example, see Patent Document 1). According to this fuel cell device, heat dissipation to the outside can be suppressed, and the temperature of the power generation air and the various components of the fuel cell device can be easily controlled.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2017-199658

[0004] In the aforementioned fuel cell system, although the components housed inside the frame are covered by air supply paths (a first air supply path and a second air supply path), this alone is not sufficient to suppress heat dissipation outside the frame, raising concerns about reduced power generation efficiency. Summary of the Invention

[0005] The main objective of this invention is to effectively suppress heat dissipation to the outside of the casing and further improve power generation efficiency.

[0006] The present invention employs the following mechanism to achieve the aforementioned main objectives.

[0007] That is, the aim of the first fuel cell system of the present invention is to include: a fuel cell that generates electricity by reacting fuel gas supplied to a fuel electrode and oxidant gas supplied to an oxidant electrode; a combustion section that combusts a combustible gas; a plurality of heat exchange sections, each having a low-temperature gas flow path for the fuel gas or oxidant gas supplied to the fuel cell (i.e., low-temperature gas) and a high-temperature gas flow path for exhaust gas discharged from the fuel cell or combustion exhaust gas discharged from the combustion section (i.e., high-temperature gas), and for exchanging heat between the low-temperature gas flowing in the low-temperature gas flow path and the high-temperature gas flowing in the high-temperature gas flow path; and a housing that is heat-insulated and houses the fuel cell, the combustion section, and the plurality of heat exchange sections, wherein the fuel cell and the combustion section are disposed in the central portion of the internal space of the housing, and one or more of the plurality of heat exchange sections are configured to cover at least a portion of the fuel cell and the combustion section from the outside.

[0008] In the first fuel cell system of this invention, the fuel cell and combustion chamber are disposed in the central part of the internal space of the casing, and one or more heat exchange chambers are arranged such that they cover at least a portion of the fuel cell and combustion chamber from the outside. This allows heat from the high-temperature components disposed in the central part, namely the fuel cell and combustion chamber, to be transferred to the components disposed on the outside (one or more heat exchange chambers), and also suppresses heat dissipation from the high-temperature components. As a result, heat dissipation to the outside of the casing can be sufficiently suppressed, further improving power generation efficiency.

[0009] Furthermore, the aim of the second fuel cell system of the present invention is to include: a fuel cell that generates electricity through the reaction of fuel gas supplied to the fuel electrode and oxidant gas supplied to the oxidant electrode; a combustion section that combusts combustible gas; and multiple heat exchange sections, each having a low-temperature gas flow path for the fuel gas or oxidant gas supplied to the fuel cell (i.e., low-temperature gas) and a high-temperature gas flow path for exhaust gas discharged from the fuel cell or combustion exhaust gas discharged from the combustion section (i.e., high-temperature gas), and for exchanging the low-temperature gas flowing in the low-temperature gas flow path with the high-temperature gas flow path. The high-temperature gas flowing in the path exchanges heat; and the shell, which is heat-insulating, houses the fuel cell, the combustion section and the plurality of heat exchange sections, and at least the fuel cell, the combustion section and the plurality of heat exchange sections are arranged in layers such that a first layer, a second layer and a third layer of temperature zones are formed sequentially from the center of the internal space of the shell outwards. The fuel cell and the combustion section are arranged in the first layer, one or more of the plurality of heat exchange sections are arranged in the second layer, and one or more of the other heat exchange sections are arranged in the third layer.

[0010] In the second fuel cell system of this invention, at least the fuel cell, the combustion chamber, and multiple heat exchange units are arranged in layers, with temperature zones forming a first layer, a second layer, and a third layer sequentially from the center of the casing outwards. The fuel cell and the combustion chamber are arranged in the first layer, one or more of the multiple heat exchange units are arranged in the second layer, and the remaining heat exchange units are arranged in the third layer. This allows heat from the high-temperature components (fuel cell and combustion chamber) located in the center to be transferred to the components (multiple heat exchange units) located on the outside, and suppresses heat dissipation from the high-temperature components. As a result, heat dissipation to the outside of the casing is sufficiently suppressed, further improving power generation efficiency.

[0011] The purpose of the third fuel cell system of the present invention is to include: a fuel cell that generates electricity by reacting fuel gas supplied to a fuel electrode and oxidant gas supplied to an oxidant electrode; a combustion section that combusts a combustible gas; a plurality of heat exchange sections, each having a low-temperature gas flow path for the fuel gas or oxidant gas supplied to the fuel cell (i.e., low-temperature gas) and a high-temperature gas flow path for exhaust gas discharged from the fuel cell or combustion exhaust gas discharged from the combustion section (i.e., high-temperature gas), and exchanging heat between the low-temperature gas flowing in the low-temperature gas flow path and the high-temperature gas flowing in the high-temperature gas flow path; and a housing that is heat-insulated and houses the fuel cell, the combustion section, and the plurality of heat exchange sections, wherein the fuel cell and the combustion section are disposed in the internal space of the housing, wherein the fuel cell is used as a first layer, and the space between the outer surface of the fuel cell and the inner surface of the housing is sequentially divided into a second layer and a third layer from the center of the housing outward, one or more of the plurality of heat exchange sections are disposed in the second layer, and one or more other heat exchange sections are disposed in the third layer.

[0012] In the third fuel cell system of this invention, with the fuel cell disposed within the interior space of the casing as the first layer, and the space between the outer surface of the fuel cell and the inner surface of the casing sequentially divided from the center of the casing outward into a second layer and a third layer, one or more heat exchange sections are disposed in the second layer, and one or more other heat exchange sections are disposed in the third layer. This allows heat from the high-temperature components, i.e., the fuel cell, to be transferred to the components disposed on the outside (the multiple heat exchange sections), and suppresses heat dissipation from the high-temperature components. As a result, heat dissipation to the outside of the casing is sufficiently suppressed, further improving power generation efficiency.

[0013] The fourth fuel cell system of the present invention comprises: a fuel cell that generates electricity by reacting fuel gas supplied to a fuel electrode and oxidant gas supplied to an oxidant electrode; a combustion section that combusts a combustible gas; a plurality of heat exchange sections, each having a low-temperature gas flow path for the fuel gas or oxidant gas supplied to the fuel cell (i.e., low-temperature gas) and a high-temperature gas flow path for exhaust gas discharged from the fuel cell or combustion exhaust gas discharged from the combustion section (i.e., high-temperature gas), and exchanging heat between the low-temperature gas flowing in the low-temperature gas flow path and the high-temperature gas flowing in the high-temperature gas flow path; and a housing that is heat-insulated and houses the fuel cell, the combustion section, and the plurality of heat exchange sections, wherein the fuel cell and the combustion section are disposed in the central portion of the internal space of the housing, one or more of the plurality of heat exchange sections are configured to cover at least a portion of the fuel cell and the combustion section from the outside, and one or more other heat exchange sections are configured to cover at least a portion of the one or more heat exchange sections from the outside.

[0014] In the fourth fuel cell system of this invention, the fuel cell and combustion chamber are disposed in the central part of the internal space of the casing. One or more heat exchange chambers are arranged such that they cover at least a portion of the fuel cell and combustion chamber from the outside. Other heat exchange chambers are arranged such that they cover at least a portion of one or more heat exchange chambers from the outside. This allows heat from the high-temperature components (i.e., the fuel cell and combustion chamber) disposed in the central part to be transferred to the components (the multiple heat exchange chambers) disposed on the outside, and it also suppresses heat dissipation from the high-temperature components. As a result, heat dissipation to the outside of the casing can be sufficiently suppressed, further improving power generation efficiency. Attached Figure Description

[0015] Figure 1 This is a simplified structural diagram of the fuel cell system 10 in this embodiment.

[0016] Figure 2 This is a simplified structural diagram of the power generation module 20.

[0017] Figure 3 This is an explanatory diagram illustrating the layered temperature zones of the power generation module 20.

[0018] Figure 4 This is a 3D view of the interior of the power generation module 20.

[0019] Figure 5 This is a 3D view of the interior of the power generation module 20.

[0020] Figure 6 This is an explanatory diagram showing other configuration examples of burner 22.

[0021] Figure 7 This is a simplified structural diagram of the power generation module 120 in other embodiments.

[0022] Figure 8 This is a simplified structural diagram of the power generation module 220 in other implementations.

[0023] Explanation of reference numerals in the attached figures

[0024] 10… Fuel cell system, 21… Fuel cell stack, 21d… Oxidant electrode outlet piping (oxidant exhaust supply line), 22… Combustor (combustion section), 31… First heat exchanger (first heat exchange section), 31a… Fuel gas flow path, 31b… Combustion exhaust gas flow path (first combustion exhaust gas flow path), 32… Second heat exchanger (second heat exchange section), 32a… Oxidant gas flow path (first oxidant gas flow path), 32b… Combustion exhaust gas flow path (second combustion gas flow path), 33… Third heat exchanger… Exchanger (third heat exchange section), 33a... Oxidant gas flow path (second oxidant gas flow path), 33b... Fuel exhaust flow path (exhaust flow path), 34, 35, 36, 37... Insulation material, 38... Module housing (housing), 41... Fuel supply pipe (fuel gas supply line), 61... Fuel exhaust piping (fuel exhaust supply line), 62... Condenser (condenser section), 64... Return fuel gas piping (return line), 65... Return combustion gas piping (fuel supply line for combustion). Detailed Implementation

[0025] Next, the configuration for implementing the present invention will be described with reference to the accompanying drawings.

[0026] Figure 1 This is a simplified structural diagram of the fuel cell system 10 according to this embodiment. Figure 2 This is a simplified structural diagram of the power generation module 20. (See diagram for example.) Figure 1 As shown, the fuel cell system 10 of this embodiment includes: a power generation module 20 including a fuel cell stack 21, a fuel supply system 40 that supplies fuel gas to the power generation module 20, an air supply system 50 that supplies air to the power generation module 20, and a recirculation system 60.

[0027] like Figure 1 , Figure 2 As shown, in addition to the fuel cell stack 21, the power generation module 20 also includes a burner 22, and first, second and third heat exchangers 31, 32 and 33, which are housed in a heat-insulated box-shaped module housing 39.

[0028] The fuel cell stack 10 comprises multiple solid oxide single cells 11, each including a solid electrolyte, a fuel electrode (anode) disposed on one side of the solid electrolyte, and an oxidant electrode (cathode) disposed on the other side of the solid electrolyte. The fuel cell stack 10 operates at a high temperature of approximately 600–800°C, therefore the solid electrolyte, fuel electrode, and oxidant electrode are made of ceramic materials. The fuel electrode uses a cermet material, combining a metal such as nickel with ceramic, which has a catalytic effect. The fuel cell stack 21 generates electricity through the reaction of hydrogen contained in the fuel gas supplied to the fuel electrode and oxygen contained in the oxidant gas (air) supplied to the oxidant electrode. Furthermore, the fuel cell stack 21 discharges fuel exhaust containing unreacted fuel gas and water vapor from the fuel electrode and air exhaust containing unreacted oxygen from the oxidant electrode. A temperature sensor (not shown) is disposed near the fuel cell stack 21. The temperature sensor detects a temperature (stack temperature) related to the temperature of the fuel cell stack 21.

[0029] like Figure 1 As shown, the fuel electrode inlet of the fuel cell stack 10 is connected to one end of a fuel electrode inlet pipe 21a, and the other end of the fuel electrode inlet pipe 21a is connected to a fuel supply system 40. The oxidant electrode inlet of the fuel cell stack 10 is connected to one end of an oxidant electrode inlet pipe 21b, and the other end of the oxidant electrode inlet pipe 21b is connected to an air supply system 50. Additionally, the fuel electrode outlet of the fuel cell stack 10 is connected to one end of a fuel electrode outlet pipe 21c, and the other end of the fuel electrode outlet pipe 21c is connected to a recirculation system 60. The oxidant electrode outlet of the fuel cell stack 10 is connected to one end of an oxidant electrode outlet pipe 21d, and the other end of the oxidant electrode outlet pipe 21d is connected to a burner 22. In addition to the oxidant electrode outlet pipe 21d, the burner 22 is also connected to a combustion gas pipe 21e and a combustion exhaust gas pipe 21f.

[0030] The burner 22 introduces fuel exhaust gas (recirculated combustion gas) through combustion gas pipe 21e and air exhaust gas through oxidizer outlet pipe 21d, thereby igniting the aforementioned mixture. The burner 22 is equipped with an ignition device for igniting the mixture and a temperature sensor for detecting the internal temperature of the burner 22.

[0031] The first and third heat exchangers 31 and 33 are flat plate heat exchangers with meandering flow paths formed internally, while the second heat exchanger 32 is a flat plate heat exchanger with meandering flow paths formed internally, which bends approximately in an L-shape in the front view. Figure 2As shown, the first heat exchanger 31 includes a fuel gas flow path 31a sandwiched in the fuel electrode inlet pipe 21a and a combustion exhaust gas flow path 31b sandwiched in the combustion exhaust gas pipe 21f, and these are brought close together to allow heat exchange between the fuel gas (supply fuel) flowing in the fuel gas flow path 31a and the combustion exhaust gas flowing in the combustion exhaust gas flow path 31b. The second heat exchanger 32 includes an oxidant gas flow path 32a sandwiched in the oxidant electrode inlet pipe 21b and a combustion exhaust gas flow path 32b sandwiched in the combustion exhaust gas pipe 21f on a downstream side of the first heat exchanger 31 (combustion exhaust gas flow path 31b), and these are brought close together to allow heat exchange between the air (supply air) flowing in the oxidant gas flow path 32a and the combustion exhaust gas flowing through the first heat exchanger 31 and in the combustion exhaust gas flow path 32b. The third heat exchanger 33 includes an oxidant gas flow path 33a sandwiched in the oxidant electrode inlet pipe 21b downstream of the second heat exchanger 32, and a fuel exhaust flow path 33b sandwiched in the fuel electrode outlet pipe 21c, and they are brought close to each other so that the supply air flowing through the second heat exchanger 32 in the oxidant gas flow path 33a exchanges heat with the fuel exhaust flowing in the fuel exhaust flow path 33b.

[0032] like Figure 1 As shown, the fuel supply system 40 includes: a fuel supply pipe 41 connected at one end to a fuel supply source and at the other end to a fuel electrode inlet pipe 21a; a fuel blower 42 installed in the fuel supply pipe 41; a regulator 43 installed upstream of the fuel blower 42 in the fuel supply pipe 41; and a flow meter 44 for detecting the flow rate of fuel gas flowing in the fuel supply pipe 41. In this embodiment, a hydrogen supply source such as a hydrogen tank is used as the fuel supply source. By operating the fuel blower 42, fuel gas (hydrogen) from the fuel supply source is supplied to the power generation module 20. Furthermore, the fuel gas supplied to the power generation module 20 is heated by heat exchange with combustion exhaust gas in the first heat exchanger 31 and then supplied to the fuel electrode of the fuel cell stack 21. Alternatively, an ammonia supply source such as an ammonia tank can also be used as the fuel supply source. The ammonia supplied to the power generation module 20 by the operation of the fuel blower 42 is decomposed into hydrogen and nitrogen by the action of the fuel electrode catalyst, and the decomposed hydrogen is used for power generation in the fuel cell stack 21.

[0033] like Figure 1As shown, the air supply system 50 includes: an air supply pipe 51 connected at one end to a filter 52 and at the other end to an oxidant electrode inlet pipe 21b; and an air blower 53 installed in the air supply pipe 51. By driving the air blower 53, air drawn into the air supply pipe 51 through the filter 52 is introduced into the oxidant electrode inlet pipe 21b, heated to the required temperature through heat exchange with combustion exhaust gas in the second heat exchanger 32 and heat exchange with fuel electrode exhaust gas in the third heat exchanger 33, and then supplied to the oxidant electrode of the fuel cell stack 10.

[0034] like Figure 1 As shown, the recirculation system 60 includes: a fuel exhaust pipe 61 connected at one end to the hydrogen electrode outlet pipe 21c of the fuel cell stack 21; a condenser 62 disposed in the fuel exhaust pipe 61; and a recirculation combustion gas pipe 63 and a recirculation fuel gas pipe 64 branching off downstream of the condenser 62 in the fuel exhaust pipe 61. The condenser 62 is a component that cools the fuel exhaust and condenses the water vapor contained in the fuel exhaust through heat exchange with the feed water. Furthermore, the condensate generated by the condensation of water vapor in the fuel exhaust in the condenser 62 is discharged through a condensate pipe.

[0035] One end of the recirculation combustion gas pipe 63 is connected to a branch point of the fuel exhaust pipe 61, and the other end of the recirculation combustion gas pipe 63 is connected to the burner 22 via the combustion gas pipe 21e. Additionally, one end of the recirculation fuel gas pipe 64 is connected to a branch point of the fuel exhaust pipe 61, and the other end of the recirculation fuel gas pipe 64 is connected between the fuel blower 42 and the regulator 43 in the fuel supply pipe 41. Thus, fuel exhaust gas passing through the condenser 62 is distributed to the recirculation combustion gas pipe 63 and the recirculation fuel gas pipe 64. The fuel exhaust gas distributed to the recirculation combustion gas pipe 63 is supplied to the burner 22 as recirculation combustion gas. Furthermore, the fuel exhaust gas distributed to the recirculation fuel gas pipe 64 flows back to the fuel supply pipe 41 and is supplied to the fuel electrode of the fuel cell stack 21 as recirculation fuel gas. Moreover, the recirculation fuel gas pipe 64 is provided with a flow orifice 65 for adjusting the distribution rate of the fuel exhaust gas.

[0036] In the fuel cell system 10 configured in this way, such as Figure 3 , Figure 4 as well as Figure 5As shown, the fuel cell stack 21 and the burner 22 are disposed close to each other in the center of the internal space of the module housing 39. The first heat exchanger 31 is disposed horizontally, covering the fuel cell stack 21 and the burner 22 from above, as shown in the figure. The third heat exchanger 33 is disposed horizontally along the side (left side) of the fuel cell stack 21, covering the fuel cell stack 21 and the burner 22 from the side (left side) of the fuel cell stack 21, as shown in the figure. Moreover, a heat insulation material 34 is disposed from the side (right side) opposite to the third heat exchanger 33 to the bottom, so as to circumferentially surround the fuel cell stack 21 and the burner 22 together with the first heat exchanger 31 and the third heat exchanger 33. In addition, the second heat exchanger 32 is disposed along the side (right side) of the heat insulation material 34 and the upper surface of the first heat exchanger 31, covering the side of the heat insulation material 34 and the top of the first heat exchanger 31. Furthermore, a flat sheet of insulating material 35 is arranged on the side (left side) opposite to the second heat exchanger 32, so as to circumferentially surround the first heat exchanger 31, the third heat exchanger 33, and the side portion of the insulating material 34 together with the second heat exchanger 32. And, as... Figure 5 As shown, a flat sheet of heat-insulating material 36 is arranged along the side (right side) of the second heat exchanger 32 to cover the side portion of the second heat exchanger 32, a flat sheet of heat-insulating material 37 is arranged along the upper surface of the second heat exchanger 32 to cover the upper portion of the second heat exchanger 32, and flat sheet of heat-insulating materials 38a and 38b are arranged to block the front (near front) and rear (inner) sides. Thus, in the internal space divided by the module housing 39, a layer of high temperature zone H1 (e.g., above 600°C) (first layer), a layer of medium temperature zone H2 (e.g., above 400°C and below 600°C) (second layer), and a layer of low temperature zone H3 (e.g., above 150°C and below 400°C) (third layer), which is lower than the medium temperature zone H2, are formed sequentially from the center outwards in the internal space. Furthermore, the configuration of the first, second, and third heat exchangers 31, 32, and 33, and the insulation materials 34, 35, 36, and 37 is not limited to this, as long as they are configured in a layered structure to cover at least a portion of the fuel cell stack 21 and the burner 22.

[0037] In this way, three temperature zones are formed within the internal space of the module housing 39 through the fuel cell stack 21, burner 22, first heat exchanger 31, second heat exchanger 32, third heat exchanger 33, and insulation materials 34, 35, 36, 37, 38a, and 38b. This allows heat from the high-temperature components located in the central part of the internal space of the module housing 39—namely, the fuel cell stack 21 and the combustion section 22—to the components located on their outer sides (the first, second, and third heat exchangers 31, 32, and 33), and also suppresses heat dissipation from the high-temperature components. As a result, heat dissipation to the outside of the module housing 39 can be effectively suppressed, further improving power generation efficiency. In particular, the first heat exchanger 31 and the second heat exchanger 32 are arranged vertically overlapping above the fuel cell stack 21 and the burner 22, so heat from the fuel cell stack 21 and the burner 22 directed upwards can be efficiently transferred to the first heat exchanger 31 and the second heat exchanger 32. Therefore, the fuel and air supplied to the fuel cell stack 21 can be heated efficiently, which can further improve the power generation efficiency.

[0038] Furthermore, fuel exhaust from the fuel electrode of the fuel cell stack 21 is supplied to a condenser 62 located outside the power generation module 20. The water vapor contained in this fuel exhaust is condensed and then supplied to the burner 22 as recirculated combustion gas. Therefore, the temperature inside the power generation module 20 can be maintained at a suitable operating temperature with a smaller fuel consumption. At this time, after exchanging heat with the supplied air through the third heat exchanger 33, the fuel exhaust is discharged outside the power generation module 20, further reducing the amount of heat dissipated outside the power generation module 20. As a result, power generation efficiency can be further improved.

[0039] Furthermore, the present invention is not limited to the above-described embodiments. Any invention that falls within the technical scope of the present invention can be implemented in various ways.

[0040] For example, in the above embodiment, although the burner 22 is disposed in the first layer between the fuel cell stack 21 and the first heat exchanger 31, as... Figure 6 As shown, it can also be configured to be placed side by side with the first heat exchanger 31, or it can be configured on the same layer (second layer) as the first heat exchanger 31 and the third heat exchanger 33. Thus, the dead space can be effectively utilized to make the power generation module 20 more compact.

[0041] Furthermore, in the above embodiment, the power generation module 20 includes first, second, and third heat exchangers 31, 32, and 33 as heat exchangers. However, if a device is used to arrange multiple heat exchangers in the internal space of the module housing 39 in such a way that multiple temperature zones are formed from its central portion outwards, the number of heat exchangers can be two or more. For example, the power generation module 20 may also include a fourth heat exchanger, which includes a fuel exhaust flow path sandwiched in the fuel electrode outlet pipe 21c downstream of the third heat exchanger 33 and a combustion gas flow path sandwiched in the combustion gas pipe 21e, and these are brought close to each other so that the fuel exhaust flowing in the fuel exhaust flow path exchanges heat with the return combustion gas flowing in the combustion gas flow path.

[0042] In the above embodiments, although the third heat exchanger 33 enables the supply air to exchange heat with the fuel exhaust, it can also enable the supply air to exchange heat with the air exhaust.

[0043] Figure 7 This is a simplified structural diagram of the power generation module 120 in other embodiments. In addition to the fuel cell stack 21 and burner 22, which are the same as those in the power generation module 20 of this embodiment, the power generation module 120 in other embodiments also includes first, second, third, and fourth heat exchangers 131, 132, 133, and 134. The first, second, third, and fourth heat exchangers 131, 132, 133, and 134 are flat plate-shaped heat exchangers with meandering flow paths formed internally. The first heat exchanger 131 includes an oxidant gas flow path 131a sandwiched in the oxidant inlet pipe 21b and a combustion exhaust gas flow path 131b sandwiched in the combustion exhaust gas pipe 21f, and these are brought close to each other so that the air (supply air) flowing in the oxidant gas flow path 131a exchanges heat with the combustion exhaust gas flowing in the combustion exhaust gas flow path 131b. The second heat exchanger 132 includes an oxidant gas flow path 132a sandwiched in the oxidant electrode inlet pipe 21b upstream of the first heat exchanger 131 (oxidant gas flow path 131a), and a combustion exhaust gas flow path 132b sandwiched in the combustion exhaust gas pipe 21f downstream of the first heat exchanger 131 (combustion exhaust gas flow path 131b). These two flow paths are brought close together, allowing the supply air flowing in the oxidant gas flow path 132a to exchange heat with the combustion exhaust gas flowing through the first heat exchanger 131 and in the combustion exhaust gas flow path 132b. The supply air passing through the second heat exchanger 132 flows in the oxidant gas flow path 131a of the first heat exchanger 131, and after exchanging heat with the combustion exhaust gas flowing in the combustion exhaust gas flow path 131b, is supplied to the oxidant electrode of the fuel cell stack 21.

[0044] The third heat exchanger 133 includes a fuel gas flow path 133a sandwiched in the fuel electrode inlet pipe 21a and a fuel exhaust flow path 133b sandwiched in the fuel electrode outlet pipe 21c, and these are brought close together to allow heat exchange between the fuel gas (supply fuel) flowing in the fuel gas flow path 133a and the fuel exhaust flowing in the fuel exhaust flow path 133b. The fourth heat exchanger 134 includes a fuel gas flow path 134a sandwiched in the fuel electrode inlet pipe 21a upstream of the third heat exchanger 133 (fuel gas flow path 133a) and a fuel exhaust flow path 134b sandwiched in the fuel electrode outlet pipe 21c downstream of the third heat exchanger 133 (fuel exhaust flow path 133b), and these are brought close together to allow heat exchange between the supply fuel flowing in the fuel gas flow path 134a and the fuel exhaust flowing through the third heat exchanger 133 and in the fuel exhaust flow path 134b. The fuel supplied through the fourth heat exchanger 134 flows in the fuel gas flow path 133a of the third heat exchanger 133, and after exchanging heat with the fuel exhaust flowing in the fuel exhaust flow path 133b, it is supplied to the fuel electrode of the fuel cell stack 21.

[0045] In other embodiments of the power generation module 120 configured in this way, such as Figure 7As shown, the first heat exchanger 131 is arranged generally horizontally, covering the fuel cell stack 21 and the burner 22 from above, as shown in the figure. The third heat exchanger 133 is arranged generally vertically along the side (left side) of the fuel cell stack 21, covering the fuel cell stack 21 and the burner 22 from the side (left side) of the fuel cell stack 21, as shown in the figure. Furthermore, a heat insulation material 34 is arranged from the side (right side) opposite to the third heat exchanger 133 to the bottom, circumferentially surrounding the fuel cell stack 21 and the burner 22 together with the first and third heat exchangers 131. Additionally, the second heat exchanger 132 is arranged generally vertically along the side (right side) of the heat insulation material 34, covering the side portion of the heat insulation material 34, and the fourth heat exchanger 134 is arranged generally horizontally along the upper surface of the first heat exchanger 131, covering the upper portion of the first heat exchanger 131. Furthermore, a flat plate-shaped heat insulation material 35 is arranged along the side (left side) of the third heat exchanger 133, together with the second heat exchanger 132 and the fourth heat exchanger 134, surrounding the side portions of the first heat exchanger 131, the third heat exchanger 133, and the heat insulation material 34. A flat plate-shaped heat insulation material 36 is arranged along the side (right side) of the second heat exchanger 132, covering its side portion. A flat plate-shaped heat insulation material 37 is arranged along the upper surface of the fourth heat exchanger 134, covering its upper portion. Flat plate-shaped heat insulation materials (not shown) are arranged to block the front (near the front) and rear (inner) sides.

[0046] In this way, by doubly surrounding the fuel cell stack 21 and the burner 22 circumferentially with the first heat exchanger 131, the second heat exchanger 132, the third heat exchanger 133, the fourth heat exchanger 134, and the insulating materials 34, 35, 36, and 37, the heat from the high-temperature components located in the central part of the module housing 39—namely, the fuel cell stack 21 and the combustion chamber 22—can be transferred to the components located on their outer sides (the first, second, third, and fourth heat exchangers 131, 132, 133, and 134), and heat dissipation from the high-temperature components can be suppressed. As a result, heat dissipation to the outside of the module housing 39 can be sufficiently suppressed, and power generation efficiency can be further improved. In particular, the first heat exchanger 131 and the fourth heat exchanger 134 are arranged vertically overlapping above the fuel cell stack 21 and the burner 22, so the heat from the fuel cell stack 21 and the burner 22 directed upwards can be efficiently transferred to the first heat exchanger 131 and the fourth heat exchanger 134. Therefore, the fuel and air supplied to the fuel cell stack 21 can be heated efficiently, which can further improve the power generation efficiency.

[0047] Figure 8This is a simplified structural diagram of the power generation module 220 in another embodiment. In addition to the fuel cell stack 21 and burner 22, which are the same as those in this embodiment, the power generation module 220 in other embodiments also includes first and second heat exchangers 231 and 232. The first and second heat exchangers 231 and 232 are flat plate heat exchangers that form meandering flow paths internally and are bent in a roughly L-shape in front view. The first heat exchanger 231 includes a fuel gas flow path 231a sandwiched in the fuel inlet pipe 21a and a combustion exhaust gas flow path 231b sandwiched in the combustion exhaust gas pipe 21f, and these are brought close to each other so that the fuel gas (supplying fuel) flowing in the fuel gas flow path 231a and the combustion exhaust gas flowing in the combustion exhaust gas flow path 231b exchange heat. The second heat exchanger 232 includes an oxidant gas flow path 232a sandwiched in the oxidant electrode inlet pipe 21b and a fuel exhaust flow path 232b sandwiched in the fuel electrode outlet pipe 21c, and brings them close to each other so that the air (supply air) flowing in the oxidant gas flow path 232a and the fuel exhaust flowing in the fuel exhaust flow path 232b can exchange heat.

[0048] In other embodiments of the power generation module 220 configured in this way, such as Figure 8 As shown, the first heat exchanger 231 is configured to cover the fuel cell stack 21 and the burner 22 from the side (left) upwards in the figure. Furthermore, a heat insulation material 34 is arranged from the side (right) opposite to the first heat exchanger 231 to the bottom, circumferentially surrounding the fuel cell stack 21 and the burner 22 together with the first heat exchanger 231. Additionally, the second heat exchanger 232 is arranged along the side (right side) of the heat insulation material 34 and the upper surface of the first heat exchanger 231, covering the side portion (right side) of the heat insulation material 34 and the upper portion of the first heat exchanger 231. Moreover, a flat plate-shaped heat insulation material 35 is arranged on the side (left) of the first heat exchanger 231, circumferentially surrounding the side (right) of the first heat exchanger 231 and the heat insulation material 34 together with the second heat exchanger 232. Furthermore, a flat heat insulation material 36 is arranged to cover the side portion (right side) of the second heat exchanger 232, and a heat insulation material 37 is arranged to cover the upper portion of the second heat exchanger 232. The flat heat insulation material (not shown) is arranged to block the front (near the front) and rear (inner side).

[0049] In this way, by doubly surrounding the fuel cell stack 21 and the burner 22 circumferentially with the first heat exchanger 231, the second heat exchanger 232, and the insulating materials 34, 35, 36, and 37, heat from the high-temperature components located in the central part of the module housing 39—namely, the fuel cell stack 21 and the combustion section 22—can be transferred to the components located on their outer sides (the first and second heat exchangers 231 and 232), and heat dissipation from the high-temperature components can be suppressed. As a result, heat dissipation to the outside of the module housing 39 can be sufficiently suppressed, further improving power generation efficiency. In particular, the first heat exchanger 231 and the second heat exchanger 234 are arranged vertically overlapping above the fuel cell stack 21 and the burner 22, so heat from the fuel cell stack 21 and the burner 22 upwards can be efficiently transferred to the first heat exchanger 231 and the second heat exchanger 232. Therefore, the fuel and air supplied to the fuel cell stack 21 can be heated efficiently, further improving power generation efficiency.

[0050] In the power generation modules 120 and 220 of the other embodiments described above, although the burner 22 is arranged in the first layer between the fuel cell stack 21 and the first heat exchangers 131 and 231, it can also be arranged to be side by side with the first heat exchangers 131 and 231, or it can be arranged in the same layer as the first heat exchangers 131 and 231 (the second layer).

[0051] In the power generation module 20 of the above embodiment, and in the power generation modules 120 and 220 of other embodiments, heat insulation material 34 is disposed at the bottom, and heat exchangers (first heat exchangers 31, 131, 231, second heat exchangers 32, 132, 232, third heat exchangers 33, 133, and fourth heat exchanger 134) and heat insulation materials 35, 36, and 37 are disposed in such a way that the fuel cell stack 21 and the burner 22 are double-enclosed from the top and sides. However, the power generation module may also be configured to at least enclose the fuel cell stack 21 around its entire circumference by one or more heat exchangers. Alternatively, the power generation module may be configured to single-layer enclose the fuel cell stack 21 from at least the top and sides by one or more heat exchangers.

[0052] Furthermore, this specification discloses the technical concept of modifying "the fuel cell system described in technical solution 1" to "the fuel cell system described in technical solution 1 or 2" in the initial application's technical solution 3, and the technical concept of modifying "the fuel cell system described in any one of technical solutions 3 to 5" to "the fuel cell system described in any one of technical solutions 3 to 6" in the initial application's technical solution 7.

[0053] [Potential for industrial applications]

[0054] This invention can be used in the manufacturing industry of fuel cell systems, etc.

Claims

1. A fuel cell system, characterized in that, have: A fuel cell generates electricity through the reaction of fuel gas supplied to the fuel electrode and oxidant gas supplied to the oxidant electrode. The combustion section, which ignites combustible gases; Multiple heat exchange sections are provided, each having a low-temperature gas flow path for fuel gas or oxidant gas (i.e., low-temperature gas) supplied to the fuel cell, and a high-temperature gas flow path for exhaust gas discharged from the fuel cell or combustion exhaust gas (i.e., high-temperature gas) discharged from the combustion section, and for exchanging heat between the low-temperature gas flowing in the low-temperature gas flow path and the high-temperature gas flowing in the high-temperature gas flow path; and The housing is heat-insulating and houses the aforementioned fuel cell, combustion chamber, and multiple heat exchange chambers. The aforementioned fuel cell and combustion unit are disposed in the central part of the internal space of the aforementioned housing. One or more of the aforementioned heat exchange sections are configured to cover at least a portion of the aforementioned fuel cell and the aforementioned combustion section from the outside.

2. The fuel cell system according to claim 1, characterized in that, One or more of the aforementioned heat exchange units are disposed above and / or to the side of the aforementioned fuel cell.

3. The fuel cell system according to claim 1, characterized in that, One or more of the aforementioned heat exchange sections are configured to further cover at least a portion of the aforementioned heat exchange section from the outside.

4. The fuel cell system according to claim 3, characterized in that, The aforementioned heat exchange units include: The first heat exchange section has a fuel gas flow path in which the fuel gas flows as the low-temperature gas and a first combustion exhaust gas flow path in which the combustion exhaust gas flows as the high-temperature gas, and the fuel gas flowing in the fuel gas flow path and the combustion exhaust gas flowing in the first combustion exhaust gas flow path exchange heat. The second heat exchange section includes a first oxidant gas flow path where the oxidant gas flows as the low-temperature gas and a second combustion exhaust gas flow path where the combustion exhaust gas, which is the high-temperature gas, flows through the first heat exchange section. The oxidant gas flowing in the first oxidant gas flow path exchanges heat with the combustion exhaust gas flowing in the second combustion exhaust gas flow path. The third heat exchange section includes a second oxidant gas flow path through which the oxidant gas, which is the aforementioned low-temperature gas, flows in the second heat exchange section, and an exhaust flow path through which the fuel exhaust or the aforementioned oxidant exhaust flows as the aforementioned high-temperature gas. The oxidant gas flowing in the second oxidant gas flow path exchanges heat with the fuel exhaust or the aforementioned oxidant exhaust flowing in the exhaust flow path. The aforementioned heat exchange unit refers to the first heat exchange unit and the third heat exchange unit. The aforementioned one or more other heat exchange units are the aforementioned second heat exchange units.

5. The fuel cell system according to claim 4, characterized in that, have: A fuel gas supply line that supplies the fuel gas to the aforementioned fuel electrode; A condenser is disposed outside the aforementioned housing and condenses the water vapor contained in the aforementioned fuel exhaust. The fuel exhaust supply line supplies the aforementioned fuel exhaust to the aforementioned condenser section; A return line that allows a portion of the fuel exhaust that has passed through the aforementioned condenser to return to the aforementioned fuel gas supply line. A combustion fuel supply line supplies another portion of the fuel exhaust gas that has passed through the aforementioned condensation section to the aforementioned combustion section; and The oxidizer exhaust supply line supplies the oxidizer exhaust gas discharged from the oxidizer electrode to the combustion section. The aforementioned third heat exchange section has a fuel exhaust flow path in which the aforementioned fuel exhaust flows as the aforementioned high-temperature gas flow, and allows the oxidant gas flowing in the aforementioned second oxidant gas flow path to exchange heat with the aforementioned fuel exhaust flowing in the aforementioned fuel exhaust flow path. The aforementioned fuel exhaust supply line supplies the fuel exhaust that has passed through the aforementioned third heat exchange section to the aforementioned condenser section.

6. The fuel cell system according to any one of claims 1 to 5, characterized in that, The aforementioned heat exchange section is configured to cover at least a portion of the aforementioned fuel cell and the aforementioned combustion section by means of a combination with insulation material.

7. The fuel cell system according to any one of claims 3 to 5, characterized in that, The aforementioned one or more heat exchange sections are configured to cover the aforementioned one or more heat exchange sections by combination with insulation material.

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