Fuel cell system

Abstract

This technology provides a way to prevent damage to the muffler. [Solution] The fuel cell system comprises a fuel cell, an exhaust pipe for discharging off-gases emitted from the fuel cell to the outside, a muffler provided on the exhaust pipe, and a pressure relief valve provided on the muffler or on the exhaust pipe upstream of the muffler. The pressure relief valve may open to reduce the pressure inside the muffler when the pressure inside the muffler exceeds a predetermined threshold.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a fuel cell system.

Background Art

[0002] Patent Document 1 discloses a fuel cell system. The fuel cell system of Patent Document 1 includes a fuel cell that receives the supply of a reaction gas, generates electricity, and discharges a reaction off-gas, a gas passage through which the reaction gas or the reaction off-gas flows, a valve device installed on the gas passage, and a control device that controls the opening degree of the valve device. When starting up the fuel cell system, the control device acquires the downstream pressure of the valve device, and when the downstream pressure is below a predetermined pressurization completion pressure, the control device performs duty control on the valve device at a predetermined duty ratio.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a fuel cell system, in order to suppress the noise generated due to the off-gas discharged from the fuel cell, a muffler may be provided in the exhaust pipe. In this configuration, when the exhaust pipe is temporarily blocked or semi-blocked due to freezing or the like, when air is supplied to the fuel cell, the pressure in the muffler may increase and the muffler may be damaged. Therefore, this specification provides a technology that can prevent the muffler from being damaged.

Means for Solving the Problems

[0005] In a first aspect of this technology, the fuel cell system comprises a fuel cell, an exhaust pipe for discharging off-gases emitted from the fuel cell to the outside, a muffler provided on the exhaust pipe, and a pressure relief valve provided on the muffler or on the exhaust pipe upstream of the muffler. The pressure relief valve may open to reduce the pressure inside the muffler when the pressure inside the muffler exceeds a predetermined threshold.

[0006] With this configuration, when the pressure inside the muffler exceeds a threshold, the pressure relief valve opens, preventing the pressure inside the muffler from rising excessively. This prevents damage to the muffler.

[0007] In a second embodiment, the pressure relief valve may be provided in the muffler in the first embodiment described above.

[0008] In a third embodiment, the fuel cell system in the first or second embodiment may include an air supply pipe for supplying an oxidizing gas to the fuel cell, and a compressor provided in the air supply pipe for pressurizing the oxidizing gas supplied to the fuel cell. [Brief explanation of the drawing]

[0009] [Figure 1] A schematic diagram showing the fuel cell system of the embodiment. [Figure 2] The diagram schematically shows the pressure relief valve of the embodiment ((a) schematically shows the pressure relief valve in the closed state, and (b) schematically shows the pressure relief valve in the open state). [Modes for carrying out the invention]

[0010] The fuel cell system 2 of the embodiment will be described with reference to the drawings. As shown in Figure 1, the fuel cell system 2 of the embodiment comprises a fuel cell 4 and a first air supply pipe 10, a second air supply pipe 20, a first exhaust pipe 30, and a second exhaust pipe 40 connected to the fuel cell 4. The fuel cell system 2 also comprises a drain pipe 36 and a circulation pipe 50.

[0011] The fuel cell system 2 is installed, for example, in a fuel cell vehicle and supplies power to the vehicle's motor. The fuel cell system 2 may also be used in applications other than fuel cell vehicles. For example, the fuel cell system 2 may be used in a stationary power supply device.

[0012] The fuel cell 4 is a device that generates electricity through a chemical reaction between hydrogen contained in the fuel gas and oxygen contained in the oxidizing gas. The fuel cell 4 is equipped with a stack 4a consisting of multiple single cells. The fuel cell 4 is equipped with one or more stacks 4a. Since the configuration of the fuel cell 4 is already known, a detailed explanation will be omitted.

[0013] The first air supply pipe 10 has its upstream end connected to a fuel gas (for example, a gas containing hydrogen) tank 12, and its downstream end connected to a fuel cell 4. The first air supply pipe 10 supplies the fuel gas stored in the tank 12 to the fuel cell 4. The tank 12 stores the fuel gas for supply to the fuel cell 4 under high pressure.

[0014] The first air supply pipe 10 is equipped with, in order from the upstream side, a tank valve 13, a pressure regulating valve 14, and an inlet valve 18. When the tank valve 13, pressure regulating valve 14, and inlet valve 18 are open, fuel gas is supplied from the tank 12 to the fuel cell 4.

[0015] The pressure regulating valve 14 regulates (reduces) the pressure of the fuel gas in the first air supply pipe 10 so that the pressure of the fuel gas downstream of the pressure regulating valve 14 is lower than the pressure of the fuel gas upstream of the pressure regulating valve 14.

[0016] The second air supply pipe 20 has its upstream end open to the outside of the fuel cell system 2 and its downstream end connected to the fuel cell 4. The second air supply pipe 20 supplies an oxidizing gas (for example, air containing oxygen) supplied from the outside to the fuel cell 4. The second air supply pipe 20 is equipped with a filter 26, a compressor 22, and a pressure sensor 24, in that order from the upstream side.

[0017] The filter 26 removes foreign matter (e.g., dust) contained in the oxidizing gas supplied to the fuel cell 4 through the second air supply pipe 20. The compressor 22 pressurizes the oxidizing gas and pumps it downstream of the second air supply pipe 20. That is, the compressor 22 pressurizes the oxidizing gas supplied to the fuel cell 4. As the compressor 22 operates, the pressurized oxidizing gas is supplied to the fuel cell 4 through the second air supply pipe 20. The pressure sensor 24 detects the pressure of the oxidizing gas in the second air supply pipe 20. That is, the pressure sensor 24 detects the pressure of the oxidizing gas supplied to the fuel cell 4 through the second air supply pipe 20.

[0018] The first exhaust pipe 30 has its upstream end connected to the fuel cell 4 and its downstream end connected to the gas-liquid separator 34. The first exhaust pipe 30 discharges the off-gas of the fuel gas emitted from the fuel cell 4 to the gas-liquid separator 34. The off-gas of the fuel gas contains gaseous hydrogen and liquid water. The first exhaust pipe 30 is provided with an outlet valve 32, and when the outlet valve 32 is open, the off-gas of the fuel gas is discharged from the fuel cell 4 to the gas-liquid separator 34. The gas-liquid separator 34 separates the gas (hydrogen) and liquid (water) contained in the off-gas of the fuel gas.

[0019] The drain pipe 36 has its upstream end connected to the gas-liquid separator 34 and its downstream end open to the outside of the fuel cell system 2. The drain pipe 36 discharges the liquid (water) separated in the gas-liquid separator 34 to the outside of the fuel cell system 2. The drain pipe 36 is equipped with an on / off valve 38, and when the on / off valve 38 is open, liquid (water) is discharged from the gas-liquid separator 34 to the outside of the fuel cell system 2. The downstream end of the drain pipe 36 may also be connected to the second exhaust pipe 40.

[0020] The circulation pipe 50 has its upstream end connected to the gas-liquid separator 34 and its downstream end connected to the first air supply pipe 10. The downstream end of the circulation pipe 50 is connected to the first air supply pipe 10 on the downstream side of the inlet valve 18. The circulation pipe 50 supplies the gas (hydrogen) separated in the gas-liquid separator 34 to the first air supply pipe 10. A compressor 52 is provided in the circulation pipe 50. When the compressor 52 operates, the gas (hydrogen) separated in the gas-liquid separator 34 is supplied to the first air supply pipe 10.

[0021] The second exhaust pipe 40 has its upstream end connected to the fuel cell 4 and its downstream end open to the outside of the fuel cell system 2. The second exhaust pipe 40 discharges the off-gas of the oxidation gas discharged from the fuel cell 4 to the outside of the fuel cell system 2. A pressure regulating valve 42 and a muffler 44 are provided in the second exhaust pipe 40 in order from the upstream side.

[0022] The pressure regulating valve 42 regulates (reduces the pressure) the pressure of the off-gas in the second exhaust pipe 40 so that the pressure of the off-gas on the downstream side of the pressure regulating valve 42 is lower than the pressure of the off-gas on the upstream side of the pressure regulating valve 42. The pressure regulating valve 42 regulates the pressure of the off-gas in the second exhaust pipe 40 so that the pressure of the oxidation gas in the fuel cell 4 becomes an appropriate pressure.

[0023] The muffler 44 is a device that suppresses the sound generated due to the off-gas flowing through the second exhaust pipe 40. The configuration of the muffler 44 is not particularly limited. The muffler 44 includes, for example, a casing and a sound-absorbing material filled in the casing. In another example, the muffler 44 may have a meandering flow path, and the off-gas passes through the flow path to suppress the sound generated due to the off-gas. The off-gas that has passed through the muffler 44 is discharged to the outside of the fuel cell system 2.

[0024] A pressure relief valve 6 is provided in the muffler 44. The pressure relief valve 6 is a device that opens when the pressure of the off-gas in the muffler 44 becomes a predetermined threshold value or more, thereby reducing the pressure of the off-gas in the muffler 44.

[0025] The specific configuration of the pressure relief valve 6 is not particularly limited. For example, as shown in FIG. 2, the pressure relief valve 6 includes a casing 60, an upstream pipe 64, a downstream pipe 66, a valve member 70, and a spring member 80. The casing 60 includes a first portion 60a that houses the valve member 70 and a second portion 60b that houses the spring member 80.

[0026] The upstream end of the upstream pipe 64 is connected to the muffler 44, and the downstream end thereof is connected to the casing 60 of the pressure relief valve 6. The upstream pipe 64 discharges the off-gas in the muffler 44 into the casing 60 of the pressure relief valve 6 when the pressure relief valve 6 is in the open state.

[0027] The upstream end of the downstream pipe 66 is connected to the casing 60 of the pressure relief valve 6, and the downstream end thereof is open to the outside of the fuel cell system 2. The downstream pipe 66 discharges the off-gas in the casing 60 of the pressure relief valve 6 to the outside.

[0028] The valve member 70 is housed in the first portion 60a of the casing 60. The valve member 70 receives the pressure of the off-gas in the muffler 44 via the upstream pipe 64. The valve member 70 opens and closes the outlet of the upstream pipe 64 according to the pressure of the off-gas in the muffler 44. The valve member 70 includes a main body portion 72, a pressing portion 76, and a shaft portion 74.

[0029] The main body portion 72 receives the pressure of the off-gas in the muffler 44. The pressing portion 76 presses the spring member 80 when the main body portion 72 receives the pressure of the off-gas. The shaft portion 74 connects the main body portion 72 and the pressing portion 76.

[0030] The spring member 80 is housed in the second portion 60b of the casing 60. The spring member 80 is configured to be expandable and contractible and presses against the pressing portion 76 of the valve member 70. The spring member 80 contracts when the pressure of the off-gas in the muffler 44, which is pressurized by the valve member 70, exceeds a predetermined threshold. As shown in Figure 2(b), the contraction of the spring member 80 causes the pressure relief valve 6 to open. When the pressure relief valve 6 is open, the off-gas in the muffler 44 is discharged to the outside of the fuel cell system 2 through the upstream pipe 64, the casing 60, and the downstream pipe 66 of the pressure relief valve 6. This reduces the pressure inside the muffler 44.

[0031] (effect) The fuel cell system 2 of the embodiment has been described above. As is clear from the above description, the fuel cell system 2 includes a second exhaust pipe 40 for discharging off-gases emitted from the fuel cell 4 to the outside, a muffler 44 provided in the second exhaust pipe 40, and a pressure relief valve 6 provided in the muffler 44. The pressure relief valve 6 opens when the pressure inside the muffler 44 exceeds a predetermined threshold, thereby reducing the pressure inside the muffler 44.

[0032] With this configuration, when the pressure inside the muffler 44 exceeds a threshold, the pressure relief valve 6 opens, thereby preventing the pressure inside the muffler 44 from rising excessively. This prevents damage to the muffler 44.

[0033] Furthermore, since the pressure relief valve 6 is provided in the muffler 44, the pressure inside the muffler 44 can be directly reduced, preventing damage to the muffler 44.

[0034] Furthermore, the fuel cell system 2 is equipped with a compressor 22 located in the second air intake pipe 20. The compressor 22 pressurizes the oxidizing gas supplied to the fuel cell 4. With this configuration, the pressure of the off-gas discharged from the fuel cell 4 also increases as the compressor 22 pressurizes the oxidizing gas supplied to the fuel cell 4, thus increasing the pressure inside the muffler 44. For this reason, the configuration of the pressure relief valve 6, which suppresses an excessive rise in pressure inside the muffler 44, is particularly effective.

[0035] Furthermore, according to the fuel cell system 2 of the embodiment, since the pressure relief valve 6 operates independently, there is no need for pressure detection sensors or control systems, thus reducing costs and size.

[0036] (modified version) In the above embodiment, the pressure relief valve 6 was provided in the muffler 44, but the configuration is not limited to this. In a modified example, the pressure relief valve 6 may be provided in the second exhaust pipe 40. In this case, the pressure relief valve 6 is provided in the second exhaust pipe 40 upstream of the muffler 44 and downstream of the pressure regulating valve 42. In this configuration as well, the pressure relief valve 6 opens when the pressure inside the muffler 44 exceeds a predetermined threshold, thereby reducing the pressure inside the muffler 44.

[0037] Although specific examples of the present invention have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving even one of these objectives itself constitutes technical usefulness. [Explanation of symbols]

[0038] 2: Fuel cell system, 4: Fuel cell, 6: Pressure relief valve, 10: First air supply pipe, 12: Tank, 13: Tank valve, 14: Pressure regulating valve, 18: Inlet valve, 20: Second air supply pipe, 22: Compressor, 24: Pressure sensor, 26: Filter, 30: First exhaust pipe, 32: Outlet valve, 34: Gas-liquid separator, 36: Drain pipe, 38: On / off valve, 40: Second exhaust pipe, 42: Pressure regulating valve, 44: Muffler, 50: Circulation pipe, 52: Compressor, 60: Casing, 64: Upstream pipe, 66: Downstream pipe, 70: Valve component, 72: Main body, 74: Shaft, 76: Pressing part, 80: Spring component

Claims

1. Fuel cells and An exhaust pipe for discharging off-gas emitted from the fuel cell to the outside, The muffler provided on the exhaust pipe, The system comprises a pressure relief valve provided in the muffler or the exhaust pipe upstream of the muffler, The pressure relief valve in the fuel cell system opens when the pressure inside the muffler exceeds a predetermined threshold, thereby reducing the pressure inside the muffler.

2. The fuel cell system according to claim 1, wherein the pressure relief valve is provided in the muffler.

3. An air supply pipe for supplying oxidizing gas to the fuel cell, The fuel cell system according to claim 1 or 2, further comprising: a compressor provided in the air supply pipe for pressurizing the oxidizing gas supplied to the fuel cell.

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