Fuel cell system

Abstract

To more miniaturize a fuel cell system.SOLUTION: A fuel cell system is equipped with approximately rectangular parallelepiped fuel cell units each including a plurality of power generation modules each of which includes a fuel cell stack for generating electric power from fuel gas and oxidant gas, and a heat-insulating module case for accommodating the fuel cell stack, a plurality of fuel supply systems containing a plurality of supply lines each of which supplies fuel gas to each of the plurality of power generation modules, a plurality of oxidant gas supply systems containing a plurality of oxidant gas supply lines each of which supplies oxidant gas to each of the plurality of power generation modules, and a frame to which the plurality of power generation modules, the plurality of fuel supply systems, and the plurality of oxidant gas supply systems are fixed.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This specification discloses a fuel cell system.

Background Art

[0002] Conventionally, as this type of fuel cell system, there has been proposed one including two fuel cell units each including a plurality of fuel cells (cell stacks) arranged in a matrix in the vertical and horizontal directions, a plurality of reformers formed in a substantially flat plate shape extending in the vertical and horizontal directions and arranged side by side in the horizontal direction, and an exhaust gas combustion part, and a substantially rectangular parallelepiped housing that houses the two fuel cell units (see, for example, Patent Document 1). In this fuel cell system, in the internal space of the housing, a plurality of fuel cells, a plurality of reformers, and an exhaust gas combustion part are arranged in this order in the front-rear direction.

[0003] Also, there has been proposed a fuel cell system including a cylindrical reformer extending in the axial direction, a plurality of cell stacks arranged side by side in the circumferential direction on the outer side in the radial direction of the reformer and facing the reformer in the radial direction, and an exhaust gas combustor arranged on the inner side in the radial direction of the reformer and facing the reformer in the radial direction (see, for example, Patent Document 2). The cell stack includes a plurality of flat plate-shaped cells laminated in the radial direction.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the fuel cell system described in Patent Document 1, since a single module is composed of a plurality of cell stacks, when arranging auxiliary machines for supplying fuel gas, air, etc. in units of modules, the size of the auxiliary machines tends to increase, leading to an increase in cost. Also, as the size of each auxiliary machine increases, it becomes difficult to accommodate the auxiliary machines in the limited space of the housing, and the size of the housing also increases due to dead space. Further, in the fuel cell system described in Patent Document 2, since it is cylindrical, the installation space to be secured does not become smaller.

[0006] The fuel cell system of the present disclosure is a fuel cell system including a plurality of fuel cell stacks, and mainly aims to make the system smaller.

Means for Solving the Problems

[0007] The fuel cell system of the present disclosure has adopted the following means to achieve the above main object.

[0008] The fuel cell system of the present disclosure includes a plurality of power generation modules each including a fuel cell stack that generates power by a fuel gas and an oxidant gas, and a heat-insulating module case that houses the fuel cell stack, a plurality of fuel supply systems including a plurality of fuel supply lines that supply the fuel gas to each of the plurality of power generation modules, a plurality of oxidant gas supply systems including a plurality of oxidant gas supply lines that supply the oxidant gas to each of the plurality of power generation modules, and a frame to which the plurality of power generation modules, the plurality of fuel supply systems, and the plurality of oxidant gas supply systems are fixed, and is characterized by including a substantially rectangular parallelepiped-shaped fuel cell unit having the above.

[0009] In the fuel cell system of the present disclosure, a power generation module including a fuel cell stack and a heat-insulating module case is accommodated, and a substantially rectangular parallelepiped fuel cell unit that accommodates a fuel supply system and an oxidant gas supply system for each power generation module is provided. By providing a fuel supply system and an oxidant gas supply system for each power generation module, the individual sizes of the constituent members (auxiliary machines) of the fuel supply system and the oxidant gas supply system can be reduced, and it becomes possible to accommodate them in the limited space of the unit. As a result, it becomes possible to reduce the dead space and make the fuel cell system more compact.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0011] Embodiments for carrying out the present disclosure will be described with reference to the drawings.

[0012] FIG. 1 is an external perspective view of the fuel cell system 10, FIG. 2 is an internal perspective view of the fuel cell unit 20 included in the fuel cell system 10, FIG. 3 is an internal side view of the fuel cell unit 20, FIG. 4 is an internal perspective view of the fuel cell unit 20 excluding the frame 21, and FIG. 5 is a schematic configuration diagram of the fuel cell system 10. Further, FIG. 6 is an external perspective view of the hydrogen blower sub-assembly 42, FIG. 7 is an external perspective view of the air blower sub-assembly 52, and FIG. 8 is an external perspective view of the condensed water tank sub-assembly 65.

[0013] As shown in FIG. 1, the fuel cell system 10 of the present embodiment includes a plurality (N) of fuel cell units 20 each including a plurality (M) of power generation modules 30. The plurality of fuel cell units 20 are arranged side by side left and right, and the power generation modules 30 are connected in series between the plurality of fuel cell units 20 to constitute the fuel cell system 10.

[0014] Each fuel cell unit 20 is a unit having a substantially rectangular parallelepiped appearance, and includes a frame 21 that supports and fixes various components of the fuel cell unit 20.

[0015] The frame 21 is configured by connecting a plurality of columns arranged on the outer periphery with beams. In the present embodiment, the columns of the frame 21 include two long front corner columns 22a and two long rear corner columns 22b arranged at the four corners, and two long side columns 22c provided between one of the front corner columns 22a and the rear corner column 22b and between the other front corner column 22a and the rear corner column 22b. Further, two short auxiliary columns 22d are provided between the two side columns 22c and the two rear corner columns 22b.

[0016] The beams of the frame 21 include a bottom beam 23a that connects the front corner posts 22a, the rear corner posts 22b, and the side posts 22c at the bottom, and a ceiling beam 23b that connects the front corner post 22a and the side post 22c at the ceiling. Further, the beams of the frame 21 include a plurality of upper and lower module fixing beams 23c that connect the rear corner post 22b and the side post 22c above the bottom beam 23a, a plurality of upper and lower hydrogen blower sub-assembly fixing beams 23d that connect the front corner post 22a and the side post 22c between the bottom beam 23a and the ceiling beam 23b, and an air blower sub-assembly fixing beam 23e that connects the side post 22c and the auxiliary post 22d between the bottom beam 23a and the lower module fixing beam 23c.

[0017] Each fuel cell unit 20 includes a power generation module 30 that includes one fuel cell stack 31, a fuel supply system 40, an air supply system 50, a circulation system 60, a waste heat recovery system 70, and an electronic control unit (ECU) 80. In the present embodiment, each fuel cell unit 20 includes a plurality (M) of power generation modules 30 (fuel cell stacks 31) connected in series. Further, the fuel supply system 40, the air supply system 50, the circulation system 60, and the electronic control unit 80 are provided one by one for each power generation module 30.

[0018] The plurality of power generation modules 30 of the fuel cell unit 20 are fixed to the plurality of upper and lower module fixing beams 23c by bolts. Each power generation module 30 all has, as shown in FIG. 5, in addition to the fuel cell stack 31, a combustor 32, a heat exchanger, and the like. These are housed in a module case 35 having heat insulation properties. The fuel cell stack 31 has a plurality of solid oxide type single cells each including an electrolyte, an anode (fuel electrode) disposed on one surface side of the electrolyte, and a cathode (air electrode) disposed on the other surface side of the electrolyte. The fuel cell stack 31 generates electricity by an electrochemical reaction between hydrogen contained in the fuel gas supplied from the fuel supply source 1 (for example, a hydrogen tank) and oxygen contained in the air.

[0019] As shown in FIGS. 2 and 3, the plurality of fuel supply systems 40 of the fuel cell unit 20 are fixed to the frame 21 so as to face the corresponding power generation modules 30 in the front-rear direction. Each fuel supply system 40 branches from the other end of a common fuel pipe 25 having one end connected to a fuel supply source 1 and is connected to an anode inlet of a corresponding fuel cell stack 31, and includes a hydrogen blower sub-assembly 42 including a hydrogen blower 43 connected to the anode gas pipe 41. An on-off valve 26 (two-way valve) is provided in the fuel pipe 25. By operating the hydrogen blower 43, the hydrogen gas from the fuel supply source 1 is supplied from the fuel pipe 25 through the anode gas pipe 41 to the corresponding power generation module 30 (the anode of the fuel cell stack 31). Since the hydrogen blower 43 is installed in each anode gas pipe 41 (branch pipe), the supply amount of hydrogen gas can be controlled for each power generation module 30 by individually controlling each hydrogen blower 43.

[0020] As shown in FIG. 6, the hydrogen blower sub-assembly 42 includes a zero governor 44 and a flow sensor 45 in addition to the hydrogen blower 43. As shown in FIG. 5, the flow sensor 45, the zero governor 44, and the hydrogen blower 43 are arranged in this order from the upstream side with respect to the anode gas pipe 41. Then, as shown in FIGS. 2 and 6, the flow sensor 45, the zero governor 44, and the hydrogen blower 43 are attached to a bracket 46, and the bracket 46 is fixed to a hydrogen blower sub-assembly fixing beam 23d of the frame 21 by bolts. The hydrogen blower sub-assembly 42 can be made detachable from the frame 21 by bolts, thereby further improving maintainability.

[0021] As shown in FIGS. 2 and 3, the plurality of air supply systems 50 of the fuel cell unit 20 are collectively arranged in the empty space at the bottom of the frame 21 (below the two power generation modules 30). Each air supply system 50 includes an air blower sub-assembly 52 including a cathode gas pipe 51 connected to the cathode inlet of the fuel cell stack 31, an air blower 53 and an air filter 54 installed in the cathode gas pipe 51. By operating the air blower 53, air is sucked from the air filter 54 into the cathode gas pipe 51, and the sucked air is supplied through the cathode gas pipe 51 to the power generation module 30 (the cathode of the fuel cell stack 31). Since the air blower 53 is installed in each cathode gas pipe 51 respectively, the supply amount of air can be controlled for each power generation module 30 by controlling each air blower 53 individually.

[0022] As shown in FIG. 5, the air blower sub-assembly 52 includes a flow rate sensor 55 in addition to the air blower 53 and the air filter 54. In the cathode gas pipe 51, the air filter 54, the air blower 53 and the flow rate sensor 55 are arranged in this order from the upstream side with respect to the cathode gas pipe 51. And, as shown in FIGS. 2 and 7, the air filter 54, the air blower 53 and the flow rate sensor 55 are attached to a bracket 56, and the bracket 56 is fixed to the bottom beam 23a or the beam 23e for fixing the air blower sub-assembly by bolts. The air blower sub-assembly 52 can be made detachable from the frame 21 by bolts, thereby further improving the maintainability.

[0023] The plurality of circulation systems 60 of the fuel cell unit 20 include an anode off-gas pipe 61 connecting the anode outlet of the fuel cell stack 31 and the combustor 32, a condenser 62 provided in the middle of the anode off-gas pipe 61, and a condensate tank sub-assembly 65 including a condensate tank 66 for storing the condensed water obtained by the condenser 62 and a drain valve 67. The condenser 62 extends in the vertical direction and is disposed between the power generation module 30 and the hydrogen blower sub-assembly 42 facing each other. The anode off-gas discharged from the anode outlet to the anode off-gas pipe 61 is supplied to the combustor 32 after the water vapor contained in the anode off-gas is condensed by heat exchange with a heat exchange medium (cooling water) in the condenser 62. Further, the condensed water generated by being condensed by the condenser 62 is stored in the condensate tank 66 disposed at the bottom of the frame 21 through a condensate water pipe 68 that branches from the downstream of the condenser 62 in the anode off-gas pipe 61 and extends downward. The drain valve 67 is provided at the bottom of the condensate tank 66, and the condensed water in the condensate tank 66 is drained through the drain valve 67. The condensate tank sub-assembly 65 (the condensate tank 66 and the drain valve 67) is attached to a bracket 69 as shown in FIGS. 2 and 8, and the bracket 69 is fixed to the bottom beam 23a of the frame 21 by bolts. The condensate tank sub-assembly 65 can be detachably attached to the frame 21 by bolts, thereby further improving the maintainability.

[0024] Furthermore, each circulation system 60 also includes a reflux pipe 63 connected between the hydrogen blower 43 and the zero governor 44 in the anode gas pipe 41 of the corresponding fuel supply system 40, which branches from downstream of the condenser 62 in the anode off-gas pipe 61. An orifice 64 is formed in the reflux pipe 63, and the reflux pipe 63 refluxes a part of the anode off-gas that has passed through the condenser 62 and supplies it from the fuel supply system 40 to the power generation module 30. The remainder of the anode off-gas passes through the anode off-gas pipe 61 as it is and is supplied to the combustor 32, where it is combusted.

[0025] As shown in FIG. 5, the exhaust heat recovery system 70 includes a plurality of combustion exhaust gas pipes 72 having one end connected to the combustor 32 of each power generation module 30, a collective pipe 73 connected to the other ends of the plurality of combustion exhaust gas pipes 72, and a heat exchanger 71 provided in the collective pipe 73. The combustion exhaust gas discharged from the combustor 32 of each power generation module 30 into the combustion exhaust gas pipe 72 gathers in the collective pipe 73, exchanges heat with the heat exchange medium in the heat exchanger 71, and is then discharged to the outside air. The heat recovered by the heat exchange with the heat exchange medium is supplied to heat utilization equipment installed in a factory or the like.

[0026] The plurality of electronic control units 80 of each fuel cell unit 20 are for controlling the operation of the corresponding power generation module 30 and are provided for each power generation module 30. Each electronic control unit 80 is configured as a microprocessor centered on a CPU and has, in addition to the CPU, a ROM, a RAM, input / output ports, and the like. Detection signals from a flow rate sensor 45 of the corresponding fuel supply system 40, a flow rate sensor 55 of the corresponding air supply system 50, and the like are input to the electronic control unit 80 via the input port. On the other hand, control signals from the electronic control unit 80 to a hydrogen blower 43 of the corresponding fuel supply system 40, an air blower 53 of the corresponding air supply system 50, a drain valve 67 of the corresponding circulation system 60, and the like are output via the output port. As shown in FIG. 2, the plurality of electronic control units 80 are attached to a bracket 86, and the bracket 86 is fixed to the auxiliary column 22d with bolts.

[0027] In this embodiment, the fuel cell unit 20 has a plurality (M) of fuel cell stacks 31 connected in series, and the fuel cell system 10 has a plurality (N) of fuel cell units 20 connected such that each fuel cell stack 31 is connected in series between the plurality of fuel cell units 20. As a result, in the fuel cell system 10, N×M fuel cell stacks 31 are connected in series to obtain a large power generation output. Therefore, in the fuel cell system 10, by simply changing the number of fuel cell units 20 to be connected, it is possible to meet various power generation output requirements. Further, each fuel cell unit 20 includes a plurality of power generation modules 30 (fuel cell stacks 31) having the same configuration, a fuel supply system 40 (hydrogen blower sub-assembly 42), an air supply system 50 (air blower sub-assembly 52), and a circulation system 60 (condenser 62 and condensate tank sub-assembly 65). This makes it possible to reduce the individual sizes of the constituent members (auxiliary machines) and accommodate them in the limited space of the fuel cell unit 20. As a result, while corresponding to a large power generation output, the fuel cell system 10 can be made more compact. Furthermore, the cost can be significantly reduced due to the mass production effect.

[0028] Also, as described above, since the plurality of fuel supply systems 40 (hydrogen blower sub-assemblies 42) accommodated in one fuel cell unit 20 are arranged to face the corresponding power generation module 30 front and back, the pipe lengths of the anode gas pipe 41, the anode off-gas pipe 61, and the reflux pipe 63 can be made the same. As a result, the pressure and flow rate of the gas flowing through the fuel supply lines (anode gas pipe 41, anode off-gas pipe 61, and reflux pipe 63) can be made the same. Consequently, the specifications of the constituent members of the fuel supply system 40 can be made the same, and the cost can be reduced. Also, in each electronic control unit 80, individual control logic and parameter adjustment in each power generation module 30 are not required, and the control becomes easier. Further, since the plurality of air supply systems 50 (air blower sub-assemblies 52) are collectively arranged in the empty space at the bottom of the frame 21, the dead space can be reduced and the fuel cell unit 20 can be made more compact.

[0029] In addition, since hydrogen gas is used as the fuel gas, there is no need to supply a reformer for reforming (steam reforming) the raw fuel gas (natural gas or LP gas) and water (steam) to the power generation module 30. In the present embodiment, the anode off-gas from the anode outlet is passed through the condenser 62 outside the power generation module 30 to remove at least a part of the water vapor contained in the anode off-gas and then refluxed to the fuel supply system 40 (anode gas pipe 41), so that the efficiency of the fuel cell stack 31 can be improved. Further, since the remaining anode off-gas from which at least a part of the water vapor has been removed is supplied to the combustor 32, the combustibility of the anode off-gas in the combustor 32 can be further improved.

[0030] In the above-described embodiment, the plurality of power generation modules 30 included in the fuel cell unit 20 are installed so as to be arranged in the vertical direction, but they may be installed so as to be arranged in the horizontal direction.

[0031] In the above-described embodiment, the plurality of fuel supply systems 40 included in the fuel cell unit 20 are arranged so as to face the corresponding power generation modules 30. However, the plurality of fuel supply systems 40 may be arranged at positions paired with the corresponding power generation modules 30. For example, they may be above the power generation module 30 or below the power generation module 30. However, it is desirable that the plurality of fuel supply systems 40 be arranged in the vicinity of the corresponding power generation modules 30.

[0032] In the above-described embodiment, the air supply system 50 (air blower sub-assembly 52) is arranged in the empty space at the bottom of the frame 21. However, the air supply system 50 (air blower sub-assembly 52) may be arranged at any location as long as it is an empty space within the frame 21. For example, the air supply system 50 (air blower sub-assembly 52) may be arranged so as to face the power generation module 30 on the side opposite to the fuel supply system 40.

[0033] In the above-described embodiment, the fuel cell system 10 is configured by connecting a plurality of fuel cell units 20 having the same configuration, but it may be configured by a single fuel cell unit 20.

[0034] Also, in the above-described embodiment, the plurality of fuel cell units 20 included in the fuel cell system 10 are connected in series, but they may be connected in parallel. That is, the plurality of fuel cell units 20 may be connected such that the plurality of fuel cell stacks 31 connected in series within the fuel cell unit 20 are connected in parallel between the fuel cell units 20. In this case, repairs and inspections can be performed for each fuel cell unit 20 while the fuel cell system 10 is operating. For example, when some of the fuel cell units 20 fail, the failed fuel cell unit 20 can be disconnected from the fuel cell system 10 and the fuel cell system 10 can be operated.

[0035] Also, it may be configured as a large-scale system in which a plurality of fuel cell systems 10 are connected. In this case, the plurality of fuel cell systems 10 may be connected in series. That is, the plurality of fuel cell systems 10 may be connected such that each fuel cell stack 31 connected in series between the fuel cell units 20 is further connected in series between the fuel cell systems 10. In this case, when the number of fuel cell stacks 31 included in one fuel cell unit 20 is M, the number of fuel cell units 20 included in one fuel cell system 10 is N, and the number of fuel cell systems 10 to be connected is L, M×N×L fuel cell stacks 31 are connected in series, and it is possible to respond to a demand for a larger power generation output. Also, the plurality of fuel cell systems 10 included in the large-scale system may be connected in parallel. In this case, similar to the fuel cell system 10 including the plurality of fuel cell units 20 connected in parallel, repairs and inspections can be performed for each fuel cell system 10 while the large-scale system is operating.

[0036] As described above, the embodiments for carrying out the present disclosure have been described using embodiments. However, the present disclosure is not limited to such embodiments, and it goes without saying that the present disclosure can be implemented in various forms without departing from the gist of the present disclosure.

Industrial Applicability

[0037] The present disclosure can be used in the manufacturing industry of fuel cell systems and the like.

Explanation of Reference Numerals

[0038] 10 Fuel cell system, 20 Fuel cell unit, 21 Frame, 30 Power generation module, 31 Fuel cell stack, 35 Module case, 40 Fuel supply system, 41 Anode gas pipe (fuel supply line), 43 Hydrogen blower (fuel blower), 44 Governor, 50 Air supply system (oxidant gas supply system), 51 Cathode gas pipe (oxidant gas supply line), 62 Condenser, 63 Reflux pipe (reflux line).

Claims

1. A fuel cell system comprising a plurality of power generation modules each including a fuel cell stack that generates power using a fuel gas and an oxidant gas, and a heat-insulating module case that houses the fuel cell stack, a plurality of fuel supply systems including a plurality of fuel supply lines that supply the fuel gas to each of the plurality of power generation modules, a plurality of oxidant gas supply systems including a plurality of oxidant gas supply lines that supply the oxidant gas to each of the plurality of power generation modules, and a frame to which the plurality of power generation modules, the plurality of fuel supply systems, and the plurality of oxidant gas supply systems are fixed. The fuel cell system includes a substantially rectangular parallelepiped fuel cell unit having the above components.

2. The fuel cell system according to claim 1, wherein the plurality of power generation modules of the fuel cell unit are fixed to the frame so as to be arranged in a predetermined direction, and the plurality of fuel supply systems of the fuel cell unit are fixed to the frame at positions corresponding to the corresponding power generation modules among the plurality of fuel cell modules. The fuel cell system.

3. The fuel cell system according to claim 2, wherein the position corresponding to the corresponding power generation module is a position facing the corresponding power generation module. The fuel cell system.

4. The fuel cell system according to any one of claims 1 to 3, wherein components of the plurality of fuel supply systems or components of the plurality of oxidant gas supply systems are sub-assembled and fixed to the frame via brackets. The fuel cell system.

5. The fuel cell system according to any one of claims 1 to 3, including a plurality of condensers that each condense at least a part of the water vapor contained in the fuel off-gas discharged from the corresponding power generation module among the plurality of power generation modules, and a plurality of reflux lines that each reflux the fuel off-gas that has passed through the corresponding condenser among the plurality of condensers to the corresponding fuel supply line, wherein, in each of the plurality of fuel supply lines, a governor and a fuel blower are provided in order from the upstream side, the plurality of reflux lines reflux the fuel off-gas between the fuel blower and the governor in the fuel supply line, and the pipe length of the fuel supply line on the downstream side of the fuel blower is the same in the plurality of fuel supply systems. The fuel cell system.

6. The fuel cell system according to claim 5, A plurality of water recovery systems including a plurality of tanks for storing condensed water generated by each of the plurality of condensers. The components of the plurality of water recovery systems are sub-assembled and fixed to the frame via brackets. Fuel cell system.

7. The fuel cell system according to any one of claims 1 to 3, Comprising a plurality of fuel cell units as the fuel cell unit, The fuel cell stacks respectively included in the plurality of fuel cell units are connected in series or in parallel among the plurality of fuel cell units. Fuel cell system.

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