JP7059660B2 - Exhaust flow path forming body for fuel cells - Google Patents

Description

The present invention relates to an exhaust flow path forming body for a fuel cell.

A fuel cell system including a fuel cell that generates power by an electrochemical reaction between hydrogen gas as a fuel gas and oxygen contained in air as an oxidant gas is known. Fuel off gas and oxidation off gas are discharged from the fuel cell. Fuel off-gas includes water produced by electrochemical reactions and hydrogen gas emitted without contributing to power generation in fuel cells. When the fuel off gas is discharged into the atmosphere, it is required to reduce the hydrogen gas concentration. Therefore, the concentration of hydrogen gas in the exhaust gas may be reduced by mixing and stirring the off-oxidation gas and the off-fuel gas. For example, Patent Document 1 discloses a fuel cell system including a diluting unit that mixes and dilutes the fuel off gas discharged from the fuel cell with the oxidation off gas. In such a diluted portion, the fuel off-gas pipe is connected to the oxide-off gas pipe so as to face the upstream side of the oxidation-off gas discharge flow path, so that the fuel-off gas can be smoothly mixed with the oxide-off gas, and the fuel-off gas is good. Can be diluted to.

Japanese Unexamined Patent Publication No. 2009-123578

In the fuel cell system described in Patent Document 1, the diameter of the fuel off-gas pipe is much smaller than the diameter of the oxidation-off gas pipe. If the diameter of the fuel off-gas pipe is small, the fuel-off gas pipe may be frozen by the water contained in the fuel-off gas in a low temperature environment such as below freezing point. On the other hand, if the diameter of the fuel off-gas pipe is large, the difference between the diameter of the fuel off-gas pipe and the diameter of the oxide-off gas pipe becomes small, and the flow velocity of the fuel-off gas when mixing the fuel-off gas with the oxide-off gas becomes small, so that the fuel The inventor of the present application has found that the off-gas and the oxidized off-gas cannot be sufficiently stirred. If the fuel off gas and the oxidation off gas cannot be sufficiently agitated, the hydrogen gas concentration in the exhaust gas may not be reduced to a desired concentration. Therefore, there is a demand for a technique capable of suppressing a decrease in the agitation property of both off-gas when the fuel off-gas and the oxidation-off gas are mixed and discharged.

The present invention has been made to solve the above-mentioned problems, and can be realized as the following forms.
[Form 1] An exhaust flow path forming body for a fuel cell, which is an oxide off gas pipe forming a flow path for an oxide off gas discharged from the fuel cell, and a fuel gas contained in the fuel off gas discharged from the fuel cell. A gas-liquid separator that separates water from the fuel and a connection pipe that connects the oxide off gas pipe are provided, and the oxide off gas pipe has a straight pipe portion and a discharge direction of the oxide off gas in the straight pipe portion. It has an R portion having an R shape of 90 degrees or more and 95 degrees or less, which is connected to the end portion on the downstream side of the fuel, and the connection pipe is attached to the straight pipe portion on the upstream side in the discharge direction from the R portion. It has a connecting portion to be connected, and the angle formed by the axis of the straight pipe portion and the axis of the connecting portion is 75 degrees or more and 105 degrees or less, and the connecting portion is downstream of the discharge direction in the straight pipe portion. An exhaust flow path forming body for a fuel cell, which is an end portion on the side and is connected to an end portion on the upstream side in the discharge direction in the R portion.

(1) According to one embodiment of the present invention, an exhaust flow path forming body for a fuel cell is provided. The exhaust flow path forming body is; an oxide off gas pipe forming a flow path of the oxide off gas discharged from the fuel cell; and a gas-liquid separation for separating the fuel gas and water contained in the fuel off gas discharged from the fuel cell. A vessel and a connecting pipe connecting the oxide off gas pipe; the oxide off gas pipe are connected to a straight pipe portion and a downstream end portion of the straight pipe portion in the discharge direction of the oxide off gas. It has an R portion having an R shape of 90 degrees or more and 95 degrees or less; the connection pipe has a connection portion connected to the straight pipe portion on the upstream side of the discharge direction from the R portion; The angle formed by the axis of the straight pipe portion and the axis of the connecting portion is 75 degrees or more and 105 degrees or less.

According to the exhaust flow path forming body for the fuel cell of this form, since the R portion has an R shape of 90 degrees or more and 95 degrees or less, turbulence between the fuel off gas and the oxidation off gas is generated to cause the fuel off gas and the oxidation. Since the off gas can be mixed and the connection part is connected to the straight pipe part on the upstream side in the discharge direction from the R part, the inflow amount and the flow velocity of the fuel off gas when the fuel off gas flows into the oxidation off gas pipe. Since the angle between the axis of the straight pipe and the axis of the connection is 75 degrees or more and 105 degrees or less, the maximum amount of hydrogen gas in the mixed gas of the fuel off gas and the oxide off gas can be suppressed. The concentration can be reduced. Therefore, according to this form of the exhaust flow path forming body, it is possible to suppress a decrease in the agitation property of both off-gas when the fuel off-gas and the oxidation-off gas are mixed and discharged.

The present invention can also be realized in various forms. For example, it can be realized in the form of a fuel cell including an exhaust flow path forming body, a fuel cell system including such a fuel cell, or the like.

It is a schematic diagram which shows the structure of the fuel cell system which mounts the exhaust flow path forming body for a fuel cell in one Embodiment of this invention. It is explanatory drawing which shows the schematic structure of the exhaust flow path forming body in this embodiment. It is an enlarged view which shows the vicinity of a connection part enlarged. It is explanatory drawing which shows the effect of the exhaust flow path forming body of an embodiment.

A. Embodiment:
A1. Fuel cell system configuration:
FIG. 1 is a schematic view showing a configuration of a fuel cell system 100 on which an exhaust flow path forming body 200 for a fuel cell according to an embodiment of the present invention is mounted. The fuel cell system 100 is mounted on a vehicle, for example, and outputs electric power that is a power source of the vehicle in response to a request from the driver. The fuel cell system 100 includes a fuel cell 10, a control unit 20, an oxidant gas supply / discharge unit 30, and a fuel gas supply / discharge unit 50. The fuel cell system 100 further includes a DC / DC converter 90, a power control unit (hereinafter referred to as “PCU”) 91, and a secondary battery 92.

The fuel cell 10 is a polymer electrolyte fuel cell that generates electricity by receiving hydrogen gas and air as reaction gases. The fuel cell 10 has a stack structure in which a plurality of cells 11 are stacked. Although not shown, each cell 11 has a membrane electrode assembly in which electrodes are arranged on both sides of the electrolyte membrane, a pair of gas diffusion layers sandwiching the membrane electrode assembly, and a pair of separators. The electric power generated by the fuel cell 10 is supplied to the secondary battery 92 or the load 93 via the DC / DC converter 90 and the PCU 91.

The secondary battery 92 is connected to the PCU 91. The PCU 91 includes a bidirectional DC / DC converter (not shown) connected to the secondary battery 92. The electric power of the fuel cell 10 and the secondary battery 92 is supplied to a load 93 such as a traction motor (not shown), an air compressor 32, a circulation pump 64, and various valves, which will be described later, via a power supply circuit including a PCU 91.

The oxidant gas supply / discharge unit 30 takes in air as an oxidant from the outside air and supplies it to the fuel cell 10, and discharges the oxidative off gas from the fuel cell 10 to the outside. The oxidant gas supply / discharge unit 30 includes an oxidant gas pipe 31, an air compressor 32, a first on-off valve 33, an oxidation off-gas pipe 41, and a first pressure regulating valve 42.

The oxidant gas pipe 31 communicates with the oxidant gas supply manifold formed inside the fuel cell 10. The air compressor 32 is connected to the oxidant gas pipe 31. The air compressor 32 compresses the air taken in from the outside air and supplies oxygen to the fuel cell 10 in response to the control signal from the control unit 20. The first on-off valve 33 is arranged between the air compressor 32 and the fuel cell 10, and executes and stops the supply of air from the air compressor 32 to the fuel cell 10. The oxidation-off gas pipe 41 communicates with the oxide-off gas discharge manifold formed inside the fuel cell 10. The oxidation-off gas pipe 41 discharges the oxidation-off gas discharged from each cell 11 to the outside of the fuel cell system 100. The first pressure regulating valve 42 adjusts the pressure of the cathode side off gas in the oxidation off gas pipe 41 according to the control signal from the control unit 20.

The fuel gas supply / discharge unit 50 supplies hydrogen gas as a fuel gas to the fuel cell 10, and discharges the fuel off gas from the fuel cell 10 to the outside. The fuel gas supply / discharge unit 50 includes a fuel gas pipe 51, a hydrogen gas tank 52, a second on-off valve 53, a second pressure regulating valve 54, an injector 55, a fuel off gas pipe 61, a gas / liquid separator 70, and the like. It includes a circulation pipe 63, a circulation pump 64, an exhaust / drain valve 60, a connection pipe 66, and an exhaust / drain pipe 45.

The fuel gas pipe 51 communicates with the fuel gas supply manifold formed inside the fuel cell 10. The hydrogen gas tank 52 is connected to the fuel gas pipe 51 and supplies the hydrogen gas filled therein to the fuel cell 10. The second on-off valve 53, the second pressure regulating valve 54, and the injector 55 are arranged in the fuel gas pipe 51 from the hydrogen gas tank 52 toward the fuel cell 10 in this order. The second on-off valve 53 opens and closes in response to a control signal from the control unit 20, and controls the inflow amount of hydrogen gas from the hydrogen gas tank 52 to the injector 55. The second pressure regulating valve 54 adjusts the pressure of the hydrogen gas supplied to the injector 55 to a predetermined pressure in response to the control signal from the control unit 20. The injector 55 supplies hydrogen gas to the fuel cell 10 and supplies hydrogen gas by opening and closing the valve according to the drive cycle and the opening / closing time set by the control unit 20 in response to the control signal from the control unit 20. adjust.

The fuel off-gas pipe 61 connects the fuel-off gas discharge manifold formed inside the fuel cell 10 to the gas-liquid separator 70. The fuel off-gas pipe 61 is a flow path for discharging the fuel off-gas from the fuel cell 10, and guides the fuel-off gas containing hydrogen gas, nitrogen gas, etc., which was not used in the power generation reaction, to the gas-liquid separator 70.

The gas-liquid separator 70 is connected between the fuel off-gas pipe 61 and the circulation pipe 63. The gas-liquid separator 70 separates the gas containing hydrogen gas contained in the fuel off gas in the fuel off gas pipe 61 from water, causes the gas containing hydrogen gas to flow into the circulation pipe 63, and stores water.

The circulation pipe 63 is connected to the fuel gas pipe 51 on the downstream side of the injector 55. A circulation pump 64, which is driven in response to a control signal from the control unit 20, is arranged in the circulation pipe 63. The circulation pump 64 sends out the gas (gas containing hydrogen gas) separated by the gas-liquid separator 70 to the fuel gas pipe 51. In the fuel cell system 100 of the present embodiment, the gas including the hydrogen gas contained in the fuel off gas is circulated and supplied to the fuel cell 10 again to improve the utilization efficiency of the hydrogen gas.

The exhaust drain valve 60 is an on-off valve provided in the lower part of the gas-liquid separator 70. The exhaust drain valve 60 opens and closes in response to a control signal from the control unit 20, and discharges the water separated by the gas-liquid separator 70 and a part of the fuel off gas to the connection pipe 66.

The connection pipe 66 connects the lower part of the exhaust gas drain valve 60 and the oxidation off gas pipe 41. The connection pipe 66 communicates with the oxidation off gas pipe 41. The connection pipe 66 discharges the water and fuel off gas discharged from the exhaust drain valve 60 to the oxidation off gas pipe 41. The fuel off gas that has flowed into the oxidation off gas pipe 41 via the connection pipe 66 is discharged to the outside (atmosphere) of the fuel cell system 100 via the exhaust drain pipe 45 by the force of the oxidation off gas flowing in the oxidation off gas pipe 41. .. At this time, the fuel off gas flowing into the oxidation off gas pipe 41 is mixed with the oxidation off gas and stirred, so that the hydrogen gas concentration is reduced and the fuel off gas is discharged to the outside.

In the present embodiment, the connection pipe 66 and the oxide off-gas pipe 41 form an exhaust flow path forming body 200. The connection pipe 66 has a connection portion 80 connected to the oxidation off-gas pipe 41. The connection portion 80 is connected to the axis of the oxide off gas pipe 41 (more accurately, the straight pipe portion 41a described later) in order to suppress a decrease in agitation between the fuel off gas and the oxidation off gas in the exhaust flow path forming body 200. The oxide off-gas pipe 41 and the connection pipe 66 are connected so that the angle formed by the axis of 80 is a predetermined angle. A detailed description of the connection portion 80 and the exhaust flow path forming body 200 will be described later.

The exhaust / drainage pipe 45 is connected to the oxide off gas pipe 41 on the downstream side of the connection portion 80 in the oxide off gas pipe 41. The exhaust / drain pipe 45 communicates with the outside (atmosphere), and the fuel off gas having a reduced hydrogen gas concentration in the exhaust flow path forming body, the oxidation off gas, and the water discharged from the gas / liquid separator 70 are separated from each other. It is discharged to the outside (atmosphere) of the fuel cell system 100 through the exhaust / drain pipe 45.

The control unit 20 is configured as a computer including a CPU, a memory, and an interface circuit to which the above-mentioned components are connected. The CPU of the control unit 20 functions as various functional units for performing operation control of the fuel cell system 100, for example, hydrogen gas supply control and power supply control, by executing a control program stored in the memory.

A2. Configuration of exhaust flow path forming body 200:
FIG. 2 is an explanatory diagram showing a schematic configuration of the exhaust flow path forming body 200 in the present embodiment. As shown in FIG. 2, the exhaust flow path forming body 200 includes an oxidation off-gas pipe 41 and a connection pipe 66. FIG. 2 shows an exhaust drain pipe 45 in addition to the exhaust flow path forming body 200.

The off-oxidation gas discharged from the fuel cell 10 flows toward the downstream side of the off-oxidation gas discharge direction D1 indicated by the solid arrow, and flows into the exhaust / drain pipe 45. On the other hand, the fuel off gas and water discharged from the gas-liquid separator 70 (not shown) flow in the connection pipe 66 toward the downstream side of the fuel off gas discharge direction D2 indicated by the broken line arrow, and are oxidized through the connection portion 80. It flows into the off-gas pipe 41. The off-oxidation gas that has flowed in from the upstream side of the off-oxidation gas pipe 41 and the off-gas that has flowed into the off-oxidation gas pipe 41 are mixed with each other and flow into the exhaust / drainage pipe 45.

As shown in FIG. 2, the oxidation off-gas pipe 41 has straight pipe portions 41a and 41c and an R portion 41b. The straight pipe portions 41a and 41c and the R portion 41b are integrally formed. The straight pipe portion 41a is connected to a portion on the upstream side of the oxidation off gas discharge direction D1 and is formed in the straight pipe. The R portion 41b is connected to the downstream end portion of the straight pipe portion 41a in the discharge direction D1 of the oxidation off gas. The R portion 41b has an R shape of 90 degrees or more and 95 degrees or less on the downstream side of the oxidation off gas discharge direction D1. The straight pipe portion 41c is connected to the downstream end portion of the R portion 41b on the downstream side in the oxidation off gas discharge direction D1 and is formed in the straight pipe portion. The straight pipe portion 41c is connected to the exhaust drain pipe 45 on the downstream side of the oxidation off gas discharge direction D1.

The connection portion 80 is connected to the straight pipe portion 41a of the oxidation off-gas pipe 41. That is, the connection portion 80 is connected to the oxidation off gas pipe 41 on the upstream side of the oxidation off gas discharge direction D1 with respect to the R portion 41b.

FIG. 3 is an enlarged view showing the vicinity of the connection portion 80 in an enlarged manner. As shown in FIG. 3, the oxidation off-gas pipe 41 and the connection pipe 66 have a tubular appearance shape. In FIG. 3, the axis CX1 of the straight pipe portion 41a in the oxide off-gas pipe 41 is shown by a alternate long and short dash line, and the axial line CX2 of the connection portion 80 is indicated by a alternate long and short dash line. The axis X is a straight line parallel to the horizontal plane.

As shown in FIG. 3, the connecting portion 80 is connected to the straight pipe portion 41a on the upstream side of the oxidation off gas discharge direction D1 from the R portion 41b. In the present embodiment, the connection portion 80 is the end portion E1 on the downstream side of the oxidation off gas discharge direction D1 in the straight pipe portion 41a, and is on the upstream end portion E1 of the oxidation off gas discharge direction D1 in the R portion 41b. You are connected. More precisely, the connecting portion 80 is connected to the straight pipe portion 41a on the upstream side of the end portion E1 of the R portion 41b. Further, the angle θ1 formed by the axis X and the axis CX2 of the connecting portion 80 is 5 degrees or more. By setting the angle θ1 to 5 degrees or more, gravity can be sufficiently utilized for discharging the water separated by the gas-liquid separator 70, and when the water discharged from the gas-liquid separator 70 flows into the oxidation off-gas pipe 41. It is possible to suppress the deterioration of drainage. Further, the angle θ2 formed by the axis CX1 of the straight pipe portion 41a and the axis CX2 of the connecting portion 80 is 90 degrees.

As a result of research, the inventor of the present invention has configured the exhaust flow path forming body 200 in order to suppress a decrease in the agitation property of both off-gas when agitating the fuel off-gas and the off-oxidation gas in the oxide-off gas pipe 41. It has been found that it is preferable to satisfy the following (1) to (3).
(1) The connecting portion 80 is connected to the straight pipe portion 41a.
(2) The R portion 41b has an R shape of 90 degrees or more and 95 degrees or less.
(3) The angle θ2 formed by the axis CX1 of the straight pipe portion 41a and the axis CX2 of the connecting portion 80 is 75 degrees or more and 105 degrees or less.
Hereinafter, each (1) to (3) will be described in detail.

Generally, the flow velocity of the fluid is larger in the straight pipe portion than in the curved pipe portion. Therefore, in the oxidation off-gas pipe 41, the flow velocity in the straight pipe portion 41a is larger than that in the R portion 41b. Also, in general, as the flow velocity of the fluid increases, the pressure decreases. Therefore, by satisfying the above (1), the inflow amount of the fuel off gas when the fuel off gas flows into the oxidation off gas pipe 41 due to the pressure drop is increased as compared with the configuration in which the connection portion 80 is connected to the R portion 41b. be able to. Further, as described above, since the flow velocity is large in the straight pipe portion 41a, the flow velocity of the fuel off gas flowing into the oxidation off gas pipe 41 can be increased. Further, in general, when the flow velocity of the fluid increases, the streamline is disturbed and turbulence is likely to occur. In the straight pipe portion 41a, since the flow velocities of the oxidation off gas and the fuel off gas are relatively large, turbulence occurs in the mixed gas of the oxidation off gas and the fuel off gas. Therefore, the oxidation off gas and the fuel off gas are easily mixed, and the stirring of both off gases is promoted.

In the R portion 41b, the flow velocity of both off-gas is slower than that in the straight pipe portion 41a. However, when the R portion 41b satisfies the above (2), the streamline becomes a gentle R shape, so that a turbulent flow occurs in the mixed gas of the oxidation off gas and the fuel off gas also in the R portion 41b. Therefore, the oxidation off gas and the fuel off gas induced from the straight pipe portion 41a to the R portion 41b are easily mixed, and the agitation of both off gases is promoted.

As shown in FIG. 2, a straight pipe portion 41c is connected to the downstream side of the oxidation off gas discharge direction D1 with respect to the R portion 41b. Therefore, in the straight pipe portion 41c on the downstream side of the R portion 41b, the flow velocity of both off-gas is larger than that in the R portion 41b. Further, as described above, as the flow velocity increases, the pressure decreases and turbulence occurs. Therefore, even in the straight pipe portion 41c, the oxidation off gas and the fuel off gas are easily mixed, and the agitation of both off gases is promoted.

In the above (2), the reason why the R shape of the R portion 41b is preferably 90 degrees or more and 95 degrees or less is that the deterioration of the agitation between the oxidation off gas and the fuel off gas can be suppressed, and the oxidation off gas. This is because it is easy to mold the pipe 41 and the pressure loss of the oxidation-off gas pipe 41 can be reduced.

As shown in FIG. 3, the connecting portion 80 is connected to the straight pipe portion 41a so that the above-mentioned angle θ2 satisfies the above-mentioned (3). As a result of research, the inventor of the present invention measured the maximum concentration of hydrogen gas in the exhaust gas (hereinafter referred to as "maximum concentration") by changing the angle θ2. By setting the angle θ2 to 90 degrees, the maximum concentration could be reduced by 0.025%. Further, the inventor of the present invention reduces the maximum concentration by 0.01% by increasing the angle θ2 by 10 degrees and the maximum concentration by decreasing the angle θ2 by 15 degrees in an angle range smaller than 90 degrees. We also found an increase of 0.017%. When the angle θ2 was 75 degrees, the maximum concentration increased by 0.008% with respect to the target concentration, and the value close to the target concentration could be reached. Regarding the upper limit of the angle θ2, it is estimated that the upper limit should be 105 degrees from the relationship between 75 degrees and 90 degrees, and the above (3) is derived.

According to the exhaust flow path forming body 200 of the present embodiment described above, (1) since the connecting portion 80 is connected to the straight pipe portion 41a, the inflow of the fuel off gas when the fuel off gas flows into the oxidation off gas pipe 41. It is possible to suppress the decrease in the amount and flow velocity, and (2) since the R portion 41b has an R shape of 90 degrees or more and 95 degrees or less, turbulence between the fuel off gas and the oxidation off gas is generated, and the fuel off gas and the oxidation off gas are generated. (3) Since the angle θ2 formed by the axis CX1 of the straight pipe portion 41a and the axis CX2 of the connecting portion 80 is 75 degrees or more and 105 degrees or less, a mixed gas of the fuel off gas and the oxidation off gas. The maximum concentration of hydrogen gas inside can be reduced. Therefore, according to the exhaust flow path forming body 200 of this form, it is possible to suppress a decrease in the agitation property of both off-gas when the fuel off-gas and the oxidation-off gas are mixed and discharged.

FIG. 4 is an explanatory diagram showing the effect of the exhaust flow path forming body 200 of the embodiment. The exhaust flow path forming body 200 (sample) of the above-described embodiment was simulated by CAE (Computer Aided Engineering), and the hydrogen concentrations in the oxide off gas and the fuel off gas flowing in the oxidation off gas pipe 41 were simulated. FIG. 4 shows a cross-sectional perspective view of the exhaust flow path forming body 200 shown in FIG. Further, in FIG. 4, the distribution of the hydrogen concentration calculated by CAE is schematically shown by hatching the cross section of the fluid (gas) flowing in the oxide off-gas pipe 41 and the exhaust / drain pipe 45. Each hydrogen concentration shown in FIG. 4 shows the ratio of the hydrogen concentration to the hydrogen concentration target value when the hydrogen concentration target value is 1.

As shown in FIG. 4, the fuel off gas flowing from the connection pipe 66 to the oxidation off gas pipe 41 via the connection portion 80 connects the oxidation off gas flowing from the upstream side of the oxidation off gas pipe 41 due to inertia in the radial direction. It is driven to the opposite side of the portion 80 and flows into the oxidation off-gas pipe 41. Therefore, at the position P1, the hydrogen concentration in the gas in the oxidation off gas pipe 41 was high on the side where the fuel off gas flowed in (the connection portion 80 side). Then, when both off-gas are mixed and flowed to the downstream side of the oxidation off-gas discharge direction D1, stirring of both off-gas is promoted in the R portion 41b. Therefore, at positions P2, P3, and P4, the hydrogen concentration was high even in the portion where the hydrogen concentration was low at the position P1 (the portion far from the connection portion 80 in the radial direction).

When both off-gas are further flowed to the downstream side of the oxidation off-gas discharge direction D1, agitation of both off-gas is promoted in the straight pipe portion 41c on the downstream side of the R portion 41b. Therefore, as shown at positions P5, P6, and P7, the hydrogen concentration in both off-gas decreased toward the downstream side of the oxidation off-gas discharge direction D1. Then, as shown in the positions P8, P9 and P10, in the exhaust drain pipe 45, the hydrogen concentration in both off-gas becomes almost the same as the hydrogen concentration target value toward the downstream side of the oxidation off-gas discharge direction D1. rice field.

By satisfying the above (1) to (3) as a sample, deterioration of the agitation property of both off-gas when mixing the fuel off-gas and the oxidation-off gas is suppressed, and the hydrogen gas concentration in the exhaust gas is reduced. It is presumed that it was possible.

B. Other embodiments:
B1. Other Embodiment 1:
In the above embodiment, the connection portion 80 is connected to the end portion E1 on the downstream side of the oxidation off gas discharge direction D1 in the straight pipe portion 41a, but the present invention is not limited thereto. For example, the connection portion 80 may be connected on the end portion E1 on the upstream side of the oxidation off gas discharge direction D1 in the R portion 41b. Further, for example, the connecting portion 80 may be connected so as to sandwich the boundary portion between the straight pipe portion 41a and the R portion 41b. Further, for example, all the connecting portions 80 may be connected to the straight pipe portion 41a side. That is, in general, the connecting portion 80 may be connected to an arbitrary position of the straight pipe portion 41a. Even in such a configuration, the same effect as that of the above embodiment is obtained.

B2. Other Embodiment 2:
In the above embodiment, the angle θ2 formed by the axis CX1 of the straight pipe portion 41a and the axis CX2 of the connecting portion 80 is 90 degrees, but the present invention is not limited thereto. For example, the angle θ2 may be any angle within the range of 75 degrees or more and 105 degrees or less. Even in such a configuration, the same effect as that of the above embodiment can be obtained.

The present invention is not limited to the above-described embodiment, and can be realized with various configurations within a range not deviating from the gist thereof. For example, the technical features in the embodiments corresponding to the technical features in each embodiment described in the column of the outline of the invention are for solving a part or all of the above-mentioned problems, or one of the above-mentioned effects. It is possible to replace or combine as appropriate to achieve the part or all. Further, if the technical feature is not described as essential in the present specification, it can be appropriately deleted.

θ1, θ2 ... Angle 10 ... Fuel cell 11 ... Cell 20 ... Control unit 30 ... Oxidizing agent gas supply / discharge unit 31 ... Oxidizing agent gas piping 32 ... Air compressor 33 ... First on-off valve 41 ... Oxidation off gas piping 41a, 41c ... Direct Pipe 41b ... R 42 ... 1st pressure regulating valve 45 ... Exhaust / drain pipe 50 ... Fuel gas supply / discharging 51 ... Fuel gas piping 52 ... Hydrogen gas tank 53 ... 2nd on-off valve 54 ... 2nd pressure regulating valve 55 ... Injector 60 ... Exhaust drain valve 61 ... Fuel off gas pipe 63 ... Circulation pipe 64 ... Circulation pump 66 ... Connection pipe 70 ... Gas-liquid separator 80 ... Connection 90 ... DC / DC converter 92 ... Secondary battery 93 ... Load 100 ... Fuel cell system 200 ... Exhaust flow path forming body CX1, CX2, X ... Axis line D1 ... Oxidation off gas discharge direction D2 ... Fuel off gas discharge direction E1 ... Ends P1, P2, P3, P4, P5, P6, P7, P8, P9, P10 …position

Claims (1)

An exhaust flow path forming body for a fuel cell
Oxidation-off gas piping that forms a flow path for oxidation-off gas discharged from the fuel cell,
A connection pipe connecting the gas-liquid separator that separates the fuel gas and water contained in the fuel off gas discharged from the fuel cell and the oxidation off gas pipe.
Equipped with
The oxidation-off gas pipe has a straight pipe portion and an R portion which is connected to the downstream end portion of the straight pipe portion in the discharge direction of the oxidation-off gas and has an R shape of 90 degrees or more and 95 degrees or less.
The connection pipe has a connection portion connected to the straight pipe portion on the upstream side in the discharge direction from the R portion.
The angle between the axis of the straight pipe portion and the axis of the connection portion is 75 degrees or more and 105 degrees or less .
The connection portion is an end portion of the straight pipe portion on the downstream side in the discharge direction, and is connected to the end portion of the R portion on the upstream side in the discharge direction.
Exhaust flow path forming body for fuel cells.

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