Fuel cell housing

Abstract

The present invention provides a fuel cell casing that can join a combustion exhaust gas exhaust pipe with an inner shell and an outer shell at low cost. The fuel cell casing comprises: an inner shell that accommodates a fuel cell and a combustion unit and has a through hole on the wall; an outer shell that is arranged in a manner that is spaced relative to the outer surface of the inner shell and covers the inner shell and has a through hole on the wall that communicates with the through hole of the inner shell; and a combustion exhaust gas exhaust pipe that discharges the combustion exhaust gas from the combustion unit. The combustion exhaust gas exhaust pipe is joined to the peripheral edge of the through hole of one of the inner shell and the outer shell by welding throughout the entire circumference. In addition, the inner shell and the outer shell have an annular contact portion that contacts around each through hole, and the contact portion is joined by welding throughout the entire circumference.

Description

Technical Field

[0001] The invention relates to a fuel cell casing. Background Art

[0002] In the past, as such a fuel cell system, the following fuel cell casing has been disclosed (for example, refer to patent document 1): it comprises: a first tube member, which is arranged in a manner to surround a power generation section and has a through hole in a side wall, the power generation section having a fuel cell that generates power by using anode gas and cathode gas and a combustion section that burns anode exhaust gas to generate combustion exhaust gas; a second tube member, which is arranged in a manner to surround the first tube member and has a through hole in the side wall; a first flow path, which is formed between the outer wall of the power generation section and the inner surface of the first tube member and is used for the combustion exhaust gas to flow; a second flow path, which is formed between the outer surface of the first tube member and the inner surface of the second tube member and is used for the cathode gas to flow; a first connecting pipe member, which connects the first flow path with the outside of the second tube member; and a second connecting pipe member, which connects the second flow path with the outside of the second tube member. In this fuel cell case, the first communicating tube member is joined to the first and second tubular members by caulking one open end of the first communicating tube member to the peripheral edge portions of the through holes of the overlapping first and second tubular members.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-141758

[0006] Technical problem to be solved by the invention

[0007] However, in the joint by riveting, it is difficult to completely fix the exhaust gas discharge pipe (first connecting pipe component) to the inner shell (first cylinder component) and the outer shell (second cylinder component), and the exhaust gas discharge pipe may rotate around the axis, or the joint may loosen when external force acts on the exhaust gas discharge pipe in the radial direction. It is also possible to weld the exhaust gas discharge pipe to each through hole of the two shells throughout the entire circumference to ensure the airtightness of the space (second flow path) between the inner shell and the outer shell. However, in order to prevent excessive gaps between each through hole and the exhaust gas discharge pipe, the through holes of both sides need to be accurately aligned, which requires higher processing accuracy, resulting in increased manufacturing costs. Summary of the invention

[0008] A main object of the fuel cell case of the present invention is to provide a fuel cell case capable of reliably joining a combustion exhaust gas discharge pipe for discharging combustion exhaust gas from a combustion unit at low cost.

[0009] Means for solving technical problems

[0010] The fuel cell casing of the present invention adopts the following means to achieve the above-mentioned main object.

[0011] The fuel cell casing of the present invention is mainly provided with:

[0012] An inner casing that accommodates a fuel cell and a combustion unit that burns exhaust gas from the fuel cell, and has a through hole on a wall surface of the inner casing;

[0013] an outer shell covering the inner shell with a gap relative to the outer surface of the inner shell so as to form a predetermined gas flow path, and having a through hole in a wall surface of the outer shell communicating with the through hole of the inner shell; and

[0014] a combustion exhaust gas discharge pipe for discharging the combustion exhaust gas from the combustion unit,

[0015] The exhaust gas discharge pipe is joined to the peripheral edge of the through hole of one of the inner shell and the outer shell by welding over the entire circumference.

[0016] The inner housing and the outer housing have an annular contact portion that contacts around the through holes, and are joined by welding over the entire circumference of the contact portion.

[0017] The fuel cell casing of the present invention comprises: an inner casing that accommodates a fuel cell and a combustion unit and has a through hole on the wall surface, an outer casing that is spaced from the outer surface of the inner casing and covers the inner casing and has a through hole on the wall surface that communicates with the through hole of the inner casing, and a combustion exhaust gas discharge pipe that discharges the combustion exhaust gas from the combustion unit. The combustion exhaust gas discharge pipe is joined to the peripheral edge of the through hole of one of the inner casing and the outer casing by welding throughout the entire circumference. In addition, the inner casing and the outer casing have an annular contact portion that contacts around each through hole, and are joined by welding throughout the entire circumference of the contact portion. When the combustion exhaust gas discharge pipe is joined to the peripheral edge of the through hole of both the inner casing and the outer casing by welding, it is necessary to strictly align the through holes of the inner casing and the outer casing so that no excessive gap is generated between the outer peripheral surface of the combustion exhaust gas discharge pipe and the peripheral edge of the through hole of the inner casing and between the outer peripheral surface of the combustion exhaust gas discharge pipe and the peripheral edge of the through hole of the outer casing, thereby requiring high processing accuracy. In contrast, in the fuel cell casing of the present invention, the exhaust gas exhaust pipe only needs to be joined to one of the inner casing and the outer casing, so it is not necessary to strictly align the through holes of the inner casing and the outer casing, and high processing accuracy is not required. As a result, it is possible to achieve a fuel cell casing in which the exhaust gas exhaust pipe can be reliably joined at low cost.

[0018] In the fuel cell casing of the present invention, the combustion exhaust gas exhaust pipe may pass through the through hole of the outer casing and be joined to a peripheral edge portion of the through hole of the inner casing by welding over the entire circumference.

[0019] In the fuel cell casing of the present invention, the inner casing and the outer casing may be joined at the contact portion by penetration welding, thereby facilitating the welding process and further reducing the manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the structure of a fuel cell system including a power generation component.

[0021] Figure 2 This is a schematic diagram of the power generation component.

[0022] Figure 3 This is a three-dimensional diagram of the appearance of the power generation component.

[0023] Figure 4 is an exploded perspective view of a portion of the component housing.

[0024] Figure 5 It is a partially enlarged view showing a joint portion of the combustion exhaust gas exhaust pipe according to the present embodiment.

[0025] Figure 6 It is a partially enlarged view showing a joint portion of a combustion exhaust gas exhaust pipe of a comparative example.

[0026] Figure 7 This is a partially enlarged view showing a joint portion of a combustion exhaust gas exhaust pipe according to another embodiment.

[0027] Explanation of symbols

[0028] 10 raw fuel supply source, 20 fuel cell system, 21 casing, 30 power generation assembly, 31 fuel cell stack, 32 gasifier, 33 reformer, 34 manifold, 35 combustion unit, 36 ignition heater, 37 combustion catalyst, 40 fuel cell casing, 41, 141 inner casing, 42, 42B, 142 outer casing, 43 pipeline, 44 cathode gas introduction pipe, 45 combustion exhaust gas discharge pipe, 50 raw fuel gas supply device, 51 raw fuel gas supply pipe, 52 raw fuel gas supply valve, 53 raw fuel gas pump, 54 desulfurizer, 55 reforming water supply device, 56 reforming water supply pipe, 57 reforming water tank, 58 reforming water Pump, 60 cathode gas supply device, 61 cathode gas supply pipe, 62 blower, 70 waste heat recovery device, 71 hot water storage tank, 72 heat exchanger, 73 circulation piping, 74 circulation pump, 75 piping, 76 water purifier, 77 combustion exhaust gas exhaust pipe, 411, 421 bottom wall, 411o, 421o, 421Bo, 1411o, 1421o through holes, 412, 422 side wall, 413, 423 upper wall, 481 lower side passage, 482 side passage, 483 upper side passage, 484 stack side passage, 491 upper side passage, 492 side passage, 493 lower side passage, A surface contact portion. DETAILED DESCRIPTION

[0029] Modes for carrying out the present invention will be described with reference to the drawings.

[0030] Figure 1 This is a schematic diagram of the fuel cell system including the power generation component. Figure 2 This is a schematic diagram of the power generation component. Figure 3 This is a three-dimensional diagram of the appearance of the power generation component. Figure 4 is an exploded perspective view of a portion of the component housing. Figure 1As shown, the fuel cell system 20 of the present embodiment comprises: a power generation component 30, the power generation component 30 includes a fuel cell stack 31, the fuel cell stack 31 generates electricity by an electrochemical reaction between hydrogen in the anode gas (fuel gas) and oxygen in the cathode gas (oxidant gas); a raw fuel gas supply device 50, the raw fuel gas supply device 50 supplies the raw fuel gas (such as natural gas, LP gas) that becomes the raw material of the anode gas to the power generation component 30; a reforming water supply device 55, the reforming water supply device 55 supplies the power generation component 30 with reforming water required for reforming from the raw fuel gas to the anode gas; a cathode gas supply device 60, the cathode gas supply device 60 supplies cathode gas to the power generation component 30 (fuel cell stack 31); a power conditioner (not shown), the power conditioner is connected to the output terminal of the fuel cell stack 31 and is connected to the power system via a relay; a waste heat recovery device 70, the waste heat recovery device 70 is used to recover the waste heat generated by the power generation component 30; and a casing 21, the casing 21 contains these.

[0031] The power generation assembly 30 includes: a fuel cell stack 31, a gasifier 32, and two reformers 33, which are housed in an assembly housing 40 which is a fuel cell housing of this embodiment. Figure 2 As shown, the power generation assembly 30 has two fuel cell stacks 31, and the two fuel cell stacks 31 are arranged on a manifold 34 in a manner of being spaced apart and facing each other. The manifold 34 is arranged in the assembly housing 40. Each fuel cell stack 31 has an electrolyte such as zirconium oxide and an anode electrode and a cathode electrode sandwiching the electrolyte, and also has a Figure 1 A plurality of solid oxide-shaped single chambers are arranged in the left-right direction (horizontal direction) in the anode electrode of each single chamber. An anode gas passage (not shown) is formed in the anode electrode of each single chamber to extend in a direction perpendicular to the arrangement direction of the single chamber, that is, to extend in the up-down direction. In addition, around the cathode electrode of each single chamber, a cathode gas passage (not shown) for cathode gas circulation is formed to extend in a direction perpendicular to the arrangement direction of the single chamber, that is, to extend in the up-down direction. The anode gas passage of each single chamber is connected to the manifold 34.

[0032] The gasifier 32 and the reformer 33 of the power generation assembly 30 are arranged above the two fuel cell stacks 31 in the assembly housing 40 with a gap between the two. In the present embodiment, the gasifier 32 and the reformer 33 on one side are arranged above the fuel cell stack 31 on one side, and the reformer 33 on the other side is arranged above the fuel cell stack 31 on the other side. In addition, a combustion section 35 is defined between the fuel cell stack 31 on one side and the gasifier 32 and the reformer 33 on one side, and a combustion section 35 is defined between the fuel cell stack 31 on the other side and the reformer 33 on the other side, and the combustion section 35 generates heat required for the operation of the fuel cell stack 31 and the reaction in the gasifier 32 and the reformer 33. An ignition heater 36 is provided in each combustion section 35.

[0033] The gasifier 32 heats the raw fuel gas from the raw fuel gas supply device 50 and the reforming water from the reforming water supply device 55 by the heat from the combustion unit 35, thereby preheating the raw fuel gas and evaporating the reforming water to generate water vapor. The raw fuel gas preheated by the gasifier 32 is mixed with water vapor, and the mixed gas flows from the gasifier 32 into the reformer 33. The reformer 33 has a reforming catalyst such as Ru or Ni filled inside it, and generates hydrogen and carbon monoxide by the reaction of the mixed gas from the gasifier 32 based on the reforming catalyst (steam reforming reaction) in the presence of heat from the combustion unit 35. In addition, the reformer 33 generates hydrogen and carbon dioxide by the reaction of carbon monoxide generated by the steam reforming reaction with water vapor (carbon monoxide conversion reaction). As a result, an anode gas containing hydrogen, carbon monoxide, carbon dioxide, water vapor, unreformed raw fuel gas, etc. is generated by the reformer 33. The anode gas generated by the reformer 33 is supplied to the anode electrodes of the individual chambers via the pipe and the manifold 34 .

[0034] In addition, air containing oxygen as cathode gas is supplied to the cathode electrode of each single cell of the fuel cell stack 31 through the cathode gas passage 48 defined in the module case 40. Oxide ions (O 2 -), the oxide ions pass through the electrolyte and react with hydrogen and carbon monoxide at the anode electrode to obtain electrical energy. In each single chamber, the anode gas (hereinafter referred to as "anode exhaust gas") and cathode gas (hereinafter referred to as "cathode exhaust gas") not used for electrochemical reaction (power generation) flow out from the anode gas passage and cathode gas passage of each single chamber to the combustion unit 35 above.

[0035] The anode exhaust gas flowing into the combustion section 35 from each single chamber is a combustible gas containing fuel components such as hydrogen and carbon monoxide, and is mixed with the cathode exhaust gas containing oxygen flowing into the combustion section 35 from each single chamber. Hereinafter, the mixed gas of the anode exhaust gas and the cathode exhaust gas is referred to as "exhaust gas". In addition, when the exhaust gas (anode exhaust gas) is ignited in the combustion section 35 by ignition by the ignition heater 36, the heat required for the operation of the fuel cell stack 31, the preheating of the raw fuel gas in the gasifier 32, the generation of water vapor, the steam reforming reaction in the reformer 33, etc. is generated by the combustion of the exhaust gas. In addition, as the exhaust gas is burned, a combustion exhaust gas containing water vapor is generated in the combustion section 35. The combustion exhaust gas generated in the combustion section 35 is discharged from the combustion exhaust gas exhaust pipe 45 to the outside of the assembly housing 40 through the combustion exhaust gas passage 49 formed in the assembly housing 40.

[0036] The raw fuel gas supply device 50 includes: a raw fuel gas supply pipe 51 connecting a raw fuel supply source 10 for supplying raw fuel gas to the gasifier 32, a raw fuel gas supply valve (electromagnetic on-off valve) 52 and a raw fuel gas pump 53 installed in the raw fuel gas supply pipe 51, and a desulfurizer 54 of a normal temperature desulfurization type, for example, installed in the raw fuel gas supply pipe 51 so as to be located between the gasifier 32 and the raw fuel gas pump 53. By operating the raw fuel gas pump 53, the raw fuel gas is pressure-fed (supplied) from the raw fuel supply source 10 to the gasifier 32 via the desulfurizer 54.

[0037] The reforming water supply device 55 includes a reforming water tank 57 storing reforming water, a reforming water supply pipe 56 connecting the reforming water tank 57 and the vaporizer 32, and a reforming water pump 58 attached to the reforming water supply pipe 56. When the reforming water pump 58 is operated, the reforming water in the reforming water tank 57 is pressure-fed (supplied) to the vaporizer 32 by the reforming water pump 58.

[0038] The cathode gas supply device 60 includes a cathode gas supply pipe 61 connected to the cathode gas passage 48 formed in the module housing 40 and a blower 62 mounted on the cathode gas supply pipe 61. By operating the blower 62, air as cathode gas is pressure-fed (supplied) from an air filter (not shown) through the cathode gas passage 48 to each fuel cell stack 31.

[0039] The waste heat recovery device 70 includes a hot water storage tank 71 storing hot water, a heat exchanger 72 for performing heat exchange between the combustion exhaust gas introduced from the combustion unit 35 of the power generation unit 30 through the combustion exhaust gas passage 49 and the hot water, a circulation pipe 73 connecting the hot water storage tank 71 and the heat exchanger 72, and a circulation pump 74 installed on the circulation pipe 73. By operating the circulation pump 74, the hot water stored in the hot water storage tank 71 is introduced into the heat exchanger 72, and after the temperature is increased by heat exchange with the combustion exhaust gas in the heat exchanger 72, it is returned to the hot water storage tank 71. By performing heat exchange with the hot water in the heat exchanger 72, the water vapor in the combustion exhaust gas is condensed, thereby obtaining condensed water.

[0040] In addition, the heat exchanger 72 (the passage of the combustion exhaust gas) of the waste heat recovery device 70 is connected to the water purifier 76 via the pipe 75, and the water purifier 76 is connected to the reforming water tank 57. The condensed water obtained by condensing the water vapor in the combustion exhaust gas is purified in the water purifier 76 through the pipe 75 and introduced into the reforming water tank 57. In addition, the passage of the combustion exhaust gas of the heat exchanger 72 is connected to the combustion exhaust gas exhaust pipe 77. Thus, the exhaust gas discharged from the combustion section 35 of the power generation unit 30 and after the water is removed in the heat exchanger 72 is discharged to the atmosphere through the combustion exhaust gas exhaust pipe 77.

[0041] like Figure 2 As shown, the assembly housing 40 has: a through hole 411o is formed in the bottom wall portion 411 (see Figure 4 ) is provided in a box-shaped inner shell 41, and is arranged to cover the inner shell 41 with a gap between the outer surface of the inner shell 41 and the inner shell 41, and two through holes 421o and 421o2 are formed in the bottom wall portion 421 (see Figure 4 ) of the outer shell 42, a through hole 421o2 inserted into one side of the outer shell 42, and connected to the cathode gas passage 48 formed between the inner shell 41 and the outer shell 42, and a cathode gas introduction pipe 44 (refer to Figure 3 ) and a through hole 411o inserted into the inner shell 41 and a through hole 421o on the other side of the outer shell 42, and connected to a combustion exhaust gas passage 49 defined in the inner shell 41, and a combustion exhaust gas exhaust pipe 45 that discharges the combustion exhaust gas from the combustion exhaust gas passage 49.

[0042] The cathode gas passage 48 has: a lower passage 481 extending along the bottom surfaces of the inner shell 41 and the outer shell 42, a side passage 482 connected to the lower passage 481 and extending along the sides of the inner shell 41 and the outer shell 42, an upper passage 483 connected to the side passage 482 and extending along the top surfaces of the inner shell 41 and the outer shell 42, and a stack side passage 484 connected to the upper passage 483 and extending in a manner passing through two fuel cell stacks 31.

[0043] The lower passage 481 of the cathode gas passage 48 is formed by the bottom wall portion 411 of the inner shell 41 extending in the horizontal direction and the bottom wall portion 421 of the outer shell 42 arranged to face the bottom wall portion 411 with a gap. The lower passage 481 is connected to the cathode gas introduction pipe 44. The cathode gas introduction pipe 44 is formed in a cylindrical shape with both ends open, and one open end of the cathode gas introduction pipe 44 is joined to the through hole 421o2 formed in the bottom wall portion 421 of the outer shell 42 by welding throughout the entire circumference. The cathode gas supply pipe 61 of the cathode gas supply device 60 is connected to the other open end of the cathode gas introduction pipe 44. The side passage 482 of the cathode gas passage 48 is formed by the side wall portion 412 of the inner shell 41 extending in the vertical direction and the side wall portion 422 of the outer shell 42 arranged to face the side wall portion 412 with a gap. The upper passage 483 of the cathode gas passage 48 is formed by the upper wall portion 413 of the inner shell 41 extending in the horizontal direction and the upper wall portion 423 of the outer shell 42 arranged in a manner opposite to the upper wall portion 413 with a gap therebetween. An opening portion 413o in the shape of a long hole extending in the arrangement direction of each single chamber of the fuel cell stack 31 is formed on the upper wall portion 413 of the inner shell 41, and one end of a flat pipe 43 with both ends open is connected to the opening portion 413o. The pipe 43 extends in the up-down direction between the two fuel cell stacks 31 to form a stack side passage 484, and an opening portion 43o is formed at the other end of the pipe 43, and the opening portion 43o is used to discharge the cathode gas after passing through the pipe 43 toward the cathode electrodes of the two fuel cell stacks 31.

[0044] In addition, the combustion exhaust gas passage 49 is formed in the space between the heat insulating material 39 and the inner shell 41 arranged around the two fuel cell stacks 31. The combustion exhaust gas passage 49 has an upper passage 491 extending along the top surface of the inner shell 41, a side passage 492 communicating with the upper passage 491 and extending along the side surface of the inner shell 41, and a lower passage 493 communicating with the side passage 492 and extending along the bottom surface of the inner shell 41. The upper passage 491 is formed by the upper surface of the heat insulating material 39 and the upper wall portion 413 of the inner shell 41. The side passage 492 is formed by the side surface of the heat insulating material 39 and the side wall portion 412 of the inner shell 41. The lower passage 493 is formed by the bottom surface of the heat insulating material 39 and the bottom wall portion 411 of the inner shell 41. The lower passage 493 is communicated with the combustion exhaust gas discharge pipe 45.

[0045] like Figure 5As shown, the exhaust gas discharge pipe 45 is formed into a cylindrical shape with both ends open, and one end of the exhaust gas discharge pipe 45 passes through the through hole 421o formed in the bottom wall 421 of the outer shell 42, and is joined to the peripheral edge of the through hole 411o formed in the bottom wall 411 of the inner shell 41 by welding throughout the entire circumference. In this embodiment, the peripheral edge of the through hole 411o is extended cylindrically toward the inside of the inner shell 41 by stamping, and one end of the exhaust gas discharge pipe 45 is inserted into the cylindrical portion to form a terminal joint. The through hole 411o of the bottom wall 411 of the inner shell 41 and the exhaust gas discharge pipe 45 are welded and joined by, for example, TIG (Tungsten Inert Gas) welding, laser welding, or the like through the terminal joint. Thus, the exhaust gas discharge pipe 45 is connected to the exhaust gas passage 49 formed in the inner casing 41, so that the exhaust gas from the combustion unit 35 passing through the exhaust gas passage 49 is supplied to the heat exchanger 72 via the exhaust gas discharge pipe 45. Figure 1 As shown, the combustion exhaust gas discharge pipe 45 is filled with a combustion catalyst 37 , and when the exhaust gas remaining after combustion is discharged from the combustion exhaust gas discharge pipe 45 , it passes through the combustion catalyst 37 and is combusted again.

[0046] In addition, if Figure 5 As shown, the periphery of the through hole 421o of the outer shell 42 (bottom wall portion 421) is formed flat, and the periphery of the through hole 411o of the inner shell 41 (bottom wall portion 411) is bent toward the outer shell 42 and overlaps with the periphery of the through hole 421o of the outer shell 42 to make surface contact. The periphery of the through hole 411o of the inner shell 41 and the periphery of the through hole 421o of the outer shell 42 are in the surface contact portion A ( Figure 5 In the present embodiment, the inner shell 41 and the outer shell 42 are joined by welding over the entire circumference (the area surrounded by a single dotted line in the figure). In the present embodiment, the inner shell 41 and the outer shell 42 are irradiated with laser light to join the two by through welding. As a result, the space between the bottom wall 411 of the inner shell 41 and the bottom wall 421 of the outer shell 42 in the peripheral portion of the through holes 411o and 421o, that is, the cathode gas passage 48 (lower passage 481) is made airtight, thereby preventing gas leakage of the cathode gas.

[0047] Now, if Figure 6As shown in the comparative example, consider the case where the combustion exhaust gas discharge pipe 45 is joined to each peripheral portion of the through hole 411o of the inner shell 41 and the through hole 421Bo of the outer shell 42B by welding over the entire circumference. In this case, in order to prevent an excessive gap that causes welding defects from being formed between the outer peripheral surface of the combustion exhaust gas discharge pipe 45 and the peripheral portion of the through hole 411o of the inner shell 41, and between the outer peripheral surface of the combustion exhaust gas discharge pipe 45 and the peripheral portion of the through hole 421Bo of the outer shell 42B, it is necessary to strictly align the through holes 411o and 421Bo of both parties. Therefore, a higher processing accuracy is required, resulting in a deterioration in yield and an increase in manufacturing cost. In contrast, in the present embodiment, the through hole 421o of the outer shell 42 is formed to a sufficient extent that the combustion exhaust gas discharge pipe 45 can pass through, and the processing is not required to have high accuracy. Therefore, the inner shell 41 and the outer shell 42 including the through holes 411o and 421o can be manufactured at a low cost.

[0048] In the fuel cell casing of the present embodiment described above, the exhaust gas discharge pipe 45 is welded all around and joined to the peripheral edge of the through hole 411o formed in the bottom wall 411 of the inner casing 41, and the periphery of the through hole 411o of the inner casing 41 (bottom wall 411) is in surface contact with the periphery of the through hole 421o of the outer casing 42 (bottom wall 421), and the surface contact portion is joined by welding all around. Thus, the space between the inner casing 41 and the outer casing 42 in the periphery of the through holes 411o and 421o, that is, the cathode gas passage 48, can be made airtight, thereby preventing gas leakage of the cathode gas. In addition, the through hole 421o of the outer casing 42 is not directly joined to the exhaust gas discharge pipe 45, and therefore, it is sufficient to form it to the extent that the exhaust gas discharge pipe 45 can pass through, and high precision is not required. As a result, the through holes 411 o and 421 o can be formed by inexpensive press working, and the fuel cell case can be manufactured at low cost.

[0049] In addition, in the fuel cell case of this embodiment, the inner case 41 and the outer case 42 are joined at the surface contact portion A by penetration welding, so the welding position does not require high accuracy. As a result, the welding process can be easily automated, and the manufacturing cost can be further reduced.

[0050] In the embodiment, the combustion exhaust gas discharge pipe 45 is joined to the peripheral edge of the through hole 411o formed in the bottom wall portion 411 of the inner shell 41 by welding throughout the entire circumference, and the inner shell 41 and the outer shell 42 are joined to each other by welding at the annular surface contact portion A where the inner shell 41 and the outer shell 42 are in surface contact around the through holes 411o and 421o. Figure 7As shown, the inner shell 141 and the outer shell 142 may be joined by welding at the annular surface contact portion A around each through hole 1411o, 1421o, and the combustion exhaust gas exhaust pipe 45 may be joined to the through hole 1421o of the outer shell 142 by welding throughout the entire circumference.

[0051] In the embodiment, the surface contact portion A of the inner housing 41 and the outer housing 42 is joined by penetration welding, but may be joined by non-penetration welding.

[0052] The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the technical problem is explained. In the embodiment, the assembly case 40 is equivalent to the "fuel cell case", the fuel cell stack 31 is equivalent to the "fuel cell", the combustion unit 35 is equivalent to the "combustion unit", the inner case 41 is equivalent to the "inner case", the outer case 42 is equivalent to the "outer case", and the combustion exhaust gas exhaust pipe 45 is equivalent to the "combustion exhaust gas exhaust pipe".

[0053] In addition, the correspondence between the main elements of the embodiment and the main elements of the invention recorded in the column of means for solving technical problems is an example of a way for the embodiment to specifically explain the way in which the invention recorded in the column of means for solving technical problems is implemented, and does not limit the elements of the invention recorded in the column of means for solving technical problems. That is, the interpretation of the invention recorded in the column of means for solving technical problems should be based on the records in that column, and the embodiment is only a specific example of the invention recorded in the column of means for solving technical problems.

[0054] As mentioned above, although the form for implementing this invention was demonstrated using embodiment, this invention is not limited to such embodiment, It is a matter of course that it can be implemented in various forms within the range which does not deviate from the summary of this invention.

[0055] Possibility of Industrial Application

[0056] The present invention can be utilized in the fuel cell case manufacturing industry and the like.

Claims

1. A fuel cell housing, comprising: An inner casing that accommodates a fuel cell and a combustion unit that burns exhaust gas from the fuel cell, and has a through hole on a wall surface of the inner casing; an outer shell covering the inner shell with a gap relative to the outer surface of the inner shell so as to form a predetermined gas flow path, and having a through hole in a wall surface of the outer shell communicating with the through hole of the inner shell; and a combustion exhaust gas discharge pipe for discharging the combustion exhaust gas from the combustion unit, The exhaust gas discharge pipe is joined to the peripheral edge of the through hole of one of the inner shell and the outer shell by welding over the entire circumference. The inner housing and the outer housing have an annular contact portion that contacts around the through holes, and are joined by welding over the entire circumference of the contact portion.

2. The fuel cell housing according to claim 1, wherein: The combustion exhaust gas discharge pipe passes through the through hole of the outer casing, and is joined to a peripheral edge portion of the through hole of the inner casing by welding over the entire circumference.

3. The fuel cell housing according to claim 1 or 2, wherein: The inner housing and the outer housing are joined at the contact portion by penetration welding.

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