Fuel cell system

Abstract

To provide a fuel cell system which can improve system stability.SOLUTION: A fuel cell system comprises: a fuel cell; a fuel gas tank; a fuel gas supply pipe which connects the fuel cell to the fuel gas tank; a fuel gas exhaust pipe connected to the fuel cell; a pressure reduction valve provided on the fuel gas supply pipe; and a relief valve provided between the fuel cell and the pressure reduction valve. The relief valve has: an outer package having a valve port and an exhaust port; and a spring structure disposed inside the outer package. The spring structure has: a pedestal; a rubber sheet disposed on the valve port side of the pedestal; and a spring which presses the pedestal to the valve port side so as to close the valve port with the rubber sheet. The pedestal has a venting hole for circulating fuel gas that has permeated the rubber sheet. The venting hole has a mesh structure.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] This application relates to fuel cell systems. [Background technology]

[0002] Patent Document 1 discloses a fuel cell system having a relief valve. Specifically, the fuel cell system described in Patent Document 1 includes a fuel cell, a gas tank that stores fuel gas to be supplied to the fuel cell, a gas supply pipe connecting the gas tank and the fuel cell, a gas exhaust pipe that discharges exhaust gas from the fuel cell, a pressure reducing valve provided in the gas supply pipe, a relief valve provided between the pressure reducing valve and the fuel cell, and an exhaust tube that connects an exhaust port of the relief valve and the gas exhaust pipe.

[0003] The relief valve operates when the fuel gas pressure in the gas supply pipe exceeds a predetermined threshold due to, for example, a failure of the pressure reducing valve, and discharges the fuel gas in the pipe to the outside via the relief valve, thereby ensuring the safety of the system. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-135219 A Summary of the Invention [Problem to be solved by the invention]

[0005] Some relief valves have a structure in which the valve opening is blocked by a rubber sheet, but because high-pressure hydrogen permeates the rubber sheet, they are equipped with a vent hole to release the permeated hydrogen to the outside. However, the rubber sheet is sucked into the vent hole due to the pressure difference, and the pressure-receiving area of ​​the rubber sheet surface changes. This changes the operating pressure of the relief valve, and there is a risk that hydrogen will be released from the relief valve within the normal operating range. If hydrogen is unintentionally released from the relief valve in this way, the system control unit may detect this and execute system shutdown control.

[0006] In view of the above circumstances, a main object of the present disclosure is to provide a fuel cell system capable of improving system stability. [Means for solving the problem]

[0007] A first aspect of the present disclosure is a fuel cell system comprising: a fuel cell; a fuel gas tank for storing fuel gas to be supplied to the fuel cell; a fuel gas supply pipe connecting the fuel cell and the fuel gas tank and for circulating the fuel gas to be supplied to the fuel cell; a fuel gas exhaust pipe connected to the fuel cell and for circulating fuel gas discharged from the fuel cell; a pressure reducing valve provided in the fuel gas supply pipe; and a relief valve provided between the fuel cell and the pressure reducing valve, wherein the relief valve comprises an outer casing having a valve port and an exhaust port, and a spring structure disposed inside the outer casing, wherein the spring structure comprises a base, a rubber sheet disposed on the valve port side of the base, and a spring provided for pressing the base towards the valve port and blocking the valve port with the rubber sheet, wherein the base has a vent hole for circulating the fuel gas that has permeated through the rubber sheet, and the vent hole has a mesh structure. Effect of the Invention

[0008] In the fuel cell system of the present disclosure, a mesh structure is provided in the vent hole. This makes it possible to suppress the rubber sheet from being sucked into the vent hole due to a pressure difference, thereby suppressing changes in the pressure-receiving area of ​​the rubber sheet surface. Therefore, the fuel cell system of the present disclosure makes it possible to improve the stability of the system. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram of a fuel cell system 100. [Diagram 2] 2A is a schematic cross-sectional view of the relief valve 25. FIG. 2B is an enlarged cross-sectional view of the vicinity of a valve port 26a of the relief valve 25. [Diagram 3]2A is an enlarged cross-sectional view of the vicinity of the valve port of a relief valve not provided with a mesh structure, and FIG. 2B is a schematic diagram showing the position of an air vent hole 42b on a rubber sheet 43, taken from the viewpoint A in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The fuel cell system of the present disclosure will be described using one embodiment of a fuel cell system 100. A block diagram of the fuel cell system 100 is shown in FIG.

[0011] As shown in FIG. 1, the fuel cell system 100 includes a fuel cell 10, a fuel gas piping section 20, and an oxidizing gas piping section 30.

[0012] <Fuel cell 10> The fuel cell 10 is formed by stacking a plurality of unit cells in series. Any type of fuel cell can be used as this type of fuel cell.

[0013] <Fuel gas piping section 20> The fuel gas piping section 20 includes a fuel gas tank 21 , a fuel gas supply pipe 22 , a fuel gas discharge pipe 23 , a pressure reducing valve 24 , and a relief valve 25 .

[0014] The fuel gas tank 21 is a high-pressure tank that stores fuel gas (e.g., hydrogen gas) to be supplied to the fuel cell 10. The fuel gas supply pipe 22 is a pipe that connects the fuel cell 10 and the fuel gas tank 21 and is provided to distribute the fuel gas to be supplied to the fuel cell 10. The fuel gas exhaust pipe 23 is a pipe that is connected to the fuel cell 10 and is provided to distribute the fuel gas discharged from the fuel cell 10. The pressure reducing valve 24 is provided in the fuel gas supply pipe 22 and is a member that adjusts the pressure of the fuel gas supplied to the fuel cell 10. The relief valve 25 is provided in the fuel gas supply pipe 22 between the fuel cell 10 and the pressure reducing valve 25. The relief valve 25 operates when the fuel gas pressure in the region between the fuel cell 10 and the pressure reducing valve 24 in the fuel gas supply pipe 22 exceeds a predetermined threshold value, and reduces the fuel gas pressure by discharging the fuel gas in the fuel gas supply pipe 22 to the outside via the relief valve 25. The pressure in the region between the fuel cell 10 and the pressure reducing valve 24 is measured by a pressure measuring device (not shown).

[0015] FIG. 2A is a schematic cross-sectional view of the relief valve 25, and FIG. 2B is an enlarged cross-sectional view focusing on the vicinity of the valve port 26a of the relief valve 25.

[0016] 2(A) and (B), the relief valve 25 includes an exterior body 26 having a valve port 26a and an exhaust port 26b, and a spring structure 40 disposed inside the exterior body 26. The spring structure 40 includes a housing 41 having a hole 41a at the bottom, a base 42, a rubber sheet 43 disposed on the valve port 26a side of the base 42, and a spring 44 provided for pressing the base 42 toward the valve port 26a and closing the valve port 26a with the rubber sheet 43. The base 42 also has a vent hole 42b for allowing the fuel gas that has permeated the rubber sheet 43 to flow. In the spring structure 40, the housing 41 is an optional member.

[0017] The spring structure 40 (housing 41) is fixed to the exterior body 26 with a plurality of screws S. The hole 41a of the housing 41 is connected to the exhaust port 26b, and the fuel gas is discharged to the outside through the hole 41a and the exhaust port 26b. The surface of the base 42 on the valve port 26a side has a recess 42a, and a rubber sheet 43 is disposed in the recess 42a. The recess 42a and the rubber sheet 43 are formed to be larger than the valve port 26a, and the base 42 is pressed toward the valve port 26a by the spring 44, so that the rubber sheet 43 can block the entire valve port 26a. One end of the spring 44 is fixed to the housing 41, and the other end is fixed to the base 42. The pressure with which the spring 44 presses the base 42 can be adjusted according to the pressure at which the relief valve 25 operates. The balance of forces in the relief valve 25 is expressed by the following equation. PS=KI P: Fuel gas pressure (N / mm 2 ), S: pressure-receiving area of ​​rubber sheet 43 (mm 2 ), K: the spring constant of the spring 44 (N / mm), and I: the spring deformation of the spring 44 (mm).

[0018] Here, it is known that high-pressure fuel gas (particularly high-pressure hydrogen) permeates the rubber sheet 43. Therefore, the base 42 has a vent hole 42b for circulating the fuel gas that has permeated the rubber sheet 43. The vent hole 42b is a through-hole provided in the base 42 directly below the rubber sheet 43, and is provided along the axial center 1 of the relief valve 25. However, the position of the vent hole 42b is not limited thereto. By providing the vent hole 42b in the base 42, the fuel gas that has permeated the rubber sheet 43 can be exhausted to the outside through the hole 41a and the exhaust hole 26b.

[0019] However, if the fuel gas pressure in the region between the fuel cell 10 and the pressure reducing valve 24 in the fuel gas supply pipe 21 becomes higher than the pressure inside the relief valve 25, the pressure difference may cause the rubber sheet 43 to be sucked into the vent hole 42b (see FIG. 3(A)). This will change the pressure-receiving area S of the rubber sheet 43, causing a change in the operating pressure of the relief valve 25, which may cause the fuel gas to be released to the outside through the relief valve 25 in a situation different from that originally intended, resulting in a problem that appropriate system management cannot be achieved.

[0020] Therefore, in one embodiment, the vent hole 42b has a mesh structure 42c (FIG. 2(B)). Specifically, the mesh structure 42c is made of a metal material that is resistant to hydrogen embrittlement. For example, SUS316 can be mentioned. By providing the vent hole 42b with the mesh structure 42c, it is possible to physically prevent the rubber sheet 43 from being sucked into the vent hole 42b. For reference, FIG. 3(B) shows a schematic diagram of the position of the vent hole 42b on the rubber sheet 43 from the viewpoint A in FIG. 2(B).

[0021] The mesh structure 42c may be provided on the rubber sheet 43 side of the vent hole 42b, or may be provided over the entire vent hole 42b. The mesh structure 42c is not particularly limited in size as long as it is large enough to prevent the rubber sheet 43 from being sucked into the vent hole 42b. Even if the mesh structure 42c is provided in the vent hole 42b, the fuel gas that has permeated the rubber sheet 43 passes through the mesh structure 42c and the vent hole 42b and is discharged to the outside from the exhaust port 26b, so the function of the vent hole 42b is not impaired.

[0022] <Oxidant gas piping section 30> The oxidizing gas piping section 30 includes an oxidizing gas supply pipe 31, an oxidizing gas supply device 32, and an oxidizing gas exhaust pipe 33. The oxidizing gas supply pipe 31 is connected to the fuel cell 10, and is a pipe provided for circulating an oxidizing gas (e.g., air) to be supplied to the fuel cell 10. The oxidizing gas supply device 32 is disposed in the oxidizing gas supply pipe 31, and is a power source for supplying an oxidizing gas to the fuel cell 10, and is, for example, a pump such as an air compressor. The oxidizing gas exhaust pipe 33 is connected to the fuel cell 10, and is a pipe provided for circulating the oxidizing gas exhausted from the fuel cell 10.

[0023] The fuel cell system of the present disclosure has been described above using one embodiment. In the fuel cell system of the present disclosure, a mesh structure is provided in the vent hole. This makes it possible to suppress the rubber sheet from being sucked into the vent hole due to a pressure difference, thereby suppressing changes in the pressure-receiving area of ​​the rubber sheet surface. Therefore, the fuel cell system of the present disclosure can improve the stability of the system. [Explanation of symbols]

[0024] 10 fuel cell 20 Fuel gas piping section 21 Fuel gas tank 22 Fuel gas supply pipe 23 Fuel gas exhaust pipe 24 Pressure reducing valve 25 Relief valve 26 Exterior body 26a Valve opening 26b Exhaust port 30 Oxidant gas piping section 31 Oxidant gas supply pipe 32 Oxidant gas supply device 33 Oxidant gas exhaust pipe 40 Spring structure 41 Case 41a hole 42 Pedestal 42a Recess 42b Vent hole 42c mesh construction 43 Rubber Sheet 44 Spring

Claims

[Claim 1] A fuel cell; a fuel gas tank for storing a fuel gas to be supplied to the fuel cell; a fuel gas supply pipe that connects the fuel cell and the fuel gas tank and is provided for passing the fuel gas to be supplied to the fuel cell; a fuel gas exhaust pipe connected to the fuel cell and provided for passing the fuel gas exhausted from the fuel cell; a pressure reducing valve provided in the fuel gas supply pipe; a relief valve provided between the fuel cell and the pressure reducing valve, The relief valve includes an exterior body having a valve port and an exhaust port, and a spring structure disposed inside the exterior body, the spring structure includes a base, a rubber sheet disposed on the valve opening side of the base, and a spring provided for pressing the base toward the valve opening and closing the valve opening with the rubber sheet, the base has a vent hole for allowing the fuel gas that has passed through the rubber sheet to flow, The vent hole has a mesh structure. Fuel cell system.

Images