JP2007184109A - Oxidization gas path system and fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify valves installed in the air system of a fuel cell. <P>SOLUTION: A fuel cell system 10 comprises a supply path 206 which supplies air to a fuel cell 204, an exhaust path 208 for exhausting air from the fuel cell 204, and a bypass 210 for bypassing the air from the supply path 206 to the exhaust path 208. A three-way valve 14 is installed at the branching point of the supply path 206 and the bypass 210. A three-way valve 16 is installed at the branching point of the exhaust path 208 and the bypass path 210. The three-way valves 14 and 16 comprise a shutting mechanism for closing the supply path 206 and the exhaust path 208, and a pressure control mechanism for controlling flow rate of the supply path 206 and the exhaust path 208, respectively. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technology related to a fuel cell, and more particularly to a technology for supplying and discharging an oxidizing gas to / from a fuel cell.

  FIG. 9 is a schematic diagram showing a configuration in a typical fuel cell system. The illustrated fuel cell system 200 includes an air system 202 and a fuel cell 204. The fuel cell 204 receives supply / discharge of hydrogen gas as a fuel gas from a hydrogen system (not shown), and also receives supply / discharge of air as an oxidizing gas from the air system 202 to receive hydrogen gas and oxygen gas. Is a device that takes out electric power (electric energy) through a chemical reaction. The fuel cell system 200 is mounted on, for example, a fuel cell vehicle, and the extracted energy is supplied to a vehicle driving motor.

  The air system 202 includes a supply path 206 through which air supplied to the fuel cell 204 flows and a discharge path 208 through which air discharged from the fuel cell 204 flows. Further, a bypass path 210 that connects the supply path 206 and the discharge path 208 is provided. A humidification module 212 is provided on the fuel cell 204 side of the bypass channel 210 so as to extend over the supply channel 206 and the discharge channel 208, and performs a humidification process on the air supplied to the fuel cell 204.

  In the supply path 206, a shut valve 214 is installed on the downstream side (the fuel cell 204 side) of the bypass path 210 and the upstream side of the humidification module 212. Similarly, a shut valve 216 is installed in the discharge path 208 upstream of the bypass path 210 (fuel cell 204 side) and downstream of the humidification module 212. The shut valves 214 and 216 are valves (valves) that fully open or close the supply path 206 and the discharge path 208, respectively. In addition, a pressure regulating valve 218 is provided in the discharge path 208 on the upstream side of the humidification module 212. The pressure regulating valve 218 is a valve whose opening amount is adjusted in multiple stages or infinite stages, and plays a role of adjusting the amount of air supplied to the fuel cell 204. Further, a bypass valve 220 is provided in the bypass passage 210. The bypass valve 220 is a valve that causes air to flow from the supply path 206 to the discharge path 208 without passing through the fuel cell 204 by the opening operation.

  When the fuel cell 204 is stopped, that is, when power generation is not performed, the shut valves 214 and 216 are closed to prevent new air from flowing into the fuel cell 204. When the fuel cell 204 is started, a compressor provided upstream of the supply path 206 is driven to flow high-pressure air into the supply path 206. At this time, the shut valves 214 and 216 and the bypass valve 220 are opened. As a result, part of the air is flowed to the fuel cell 204 and used for preparation for full-scale startup, and the remaining air is quickly discharged through the bypass passage 210. During normal operation of the fuel cell 204, the bypass valve 220 is closed, and the opening / closing amount of the pressure regulating valve 218 is changed according to the amount of power generation. As a result, the amount of air supplied to the fuel cell 204 through the supply path 206 and discharged through the discharge path 208 is controlled.

  Patent Document 1 below describes a configuration in which one three-way valve and one pressure regulating valve are provided in an air system of a fuel cell system. Specifically, a three-way valve is provided at the branch between the air supply path and the bypass path, and a pressure regulating valve is provided upstream of the discharge path.

JP 2005-158282 A

  In the technique shown in FIG. 9, air is controlled by using a total of four valves, that is, a pressure regulating valve, a bypass valve, and two shut valves, and the cost is unavoidable. On the other hand, in the technique disclosed in Patent Document 1, although only two valves are used, the types of the two valves are different, so that the parts cannot be simplified. Further, the installed three-way valve selectively selects supply to the fuel cell and bypass to the bypass path, and does not perform fine flow rate control.

  An object of the present invention is to simplify a valve installed in an air system of a fuel cell.

  Another object of the present invention is to introduce a valve that enables new flow control to the air system of the fuel cell.

  Still another object of the present invention is to introduce a valve that achieves both simplification and dual system for an air system of a fuel cell.

  The oxidizing gas flow path system of the present invention connects a supply path for supplying an oxidizing gas to a fuel cell, a discharge path for discharging the oxidizing gas from the fuel cell, and a supply path and a discharge path. A first three-way valve that is provided at a branch point between the supply path and the bypass path and adjusts the amount of the oxidizing gas flowing into the fuel cell and the bypass path; a discharge path and a bypass path; And a second three-way valve that adjusts the amount of oxidizing gas flowing out from the fuel cell and the bypass.

  This oxidant gas flow path system is a system responsible for supplying and discharging oxidant gas to the fuel cell. The oxidizing gas is a gas that is supplied to the cathode of the fuel cell and oxidizes the fuel gas supplied separately to the anode. As the oxidizing gas, air (containing oxygen) is often used. In the oxidizing gas channel system, a supply channel, a discharge channel, and a bypass channel are provided as channels through which the oxidizing gas flows. The amount of oxidizing gas flowing through these flow paths is adjusted by the first three-way valve and the second three-way valve. Here, the first three-way valve is a valve that adjusts the amount of the oxidizing gas flowing from the upstream of the supply passage to the fuel cell side and the amount of the oxidizing gas to the bypass passage. The second three-way valve is a valve that adjusts the amount flowing from the upstream (fuel cell side) of the supply passage and the amount flowing from the bypass passage toward the downstream of the discharge passage.

  The first three-way valve and the second three-way valve do not necessarily have the same structure. However, from the viewpoint of reducing the number of parts, it is desirable to have the same structure (the same shape). The structures of the first three-way valve and the second three-way valve can be variously designed. For example, a structure in which the flow is controlled by closing part or all of the flow path with a plate-shaped valve body may be adopted, or a rotating body in which a flow path that can connect each flow path is formed is branched. You may make it control a flow by installing in a point and changing the angle. The valve switching is typically performed based on a command from a control unit that controls the operation of the fuel cell system.

  According to this configuration, an oxidizing gas supply / discharge system in the fuel cell can be constructed by two three-way valves. That is, it is possible to supply air to the fuel cell without providing other valves. In particular, by making the two three-way valves have the same shape, the number of parts can be reduced and the cost can be reduced.

  In one aspect of the oxidizing gas channel system of the present invention, the first three-way valve includes a mechanism that closes the supply path and does not supply the oxidizing gas to the fuel cell, or the second three-way valve discharges A mechanism is provided that closes the path and does not discharge the oxidizing gas from the fuel cell. That is, a shut mechanism that does not supply new oxidizing gas to the fuel cell is provided for one or both of the three-way valves. When both three-way valves are provided, the reliability of the shut is improved, and the advantage of the dual system that the shut can be realized even when a failure occurs in one of the valves can be secured. The closing may be performed on the upstream side of the supply path or the downstream side of the discharge path (the flow path side flowing into the three-way valve), or may be performed on the flow path side from the fuel cell rather than the three-way valve. The shut mechanism is usually used when the fuel cell is stopped.

  In one aspect of the oxidizing gas channel system of the present invention, the first three-way valve includes a mechanism for adjusting the amount of oxidizing gas flowing into the fuel cell in at least a plurality of stages, or the second three-way valve is a fuel cell. Provided with a mechanism for adjusting the amount of oxidizing gas flowing out from at least a plurality of stages. That is, a pressure regulating mechanism for adjusting the amount of oxidizing gas flowing through the fuel cell is provided for one or both of the three-way valves. When both three-way valves are provided, fine control by adjusting both valves is possible, and when a failure occurs in the pressure adjustment mechanism of one valve, the pressure adjustment mechanism is switched to the other valve. It is possible to build a dual system that continues pressure. The pressure adjusting mechanism can be realized, for example, by changing the opening amount of the supply passage or the discharge passage, and the opening amount is set to at least two stages, typically, multiple stages or infinite stages. Alternatively, the pressure adjustment mechanism may be realized by changing the opening amount of the bypass passage while keeping the opening amount of the supply passage or the discharge passage constant, or the opening amount of the supply passage or the discharge passage and the opening amount of the bypass passage. You may implement | achieve by changing both opening amount. The pressure regulating mechanism is usually used for controlling the amount of power generation during operation of the fuel cell.

  In one aspect of the oxidizing gas channel system of the present invention, the first three-way valve is provided with a mechanism that closes the bypass passage and does not flow the oxidizing gas through the bypass passage, or the second three-way valve is a bypass. A mechanism is provided that closes the path and does not discharge oxidizing gas from the bypass path. That is, a mechanism for shutting the bypass path is provided for one or both of the three-way valves. This eliminates the need to provide a dedicated bypass valve in the bypass path. If both three-way valves are provided, the reliability of the shut-off can be improved, and there is also an advantage that a dual system can be constructed in which the shut-off can be performed using the other valve even when one of the valves fails. The shut mechanism is usually used during operation of the fuel cell. Further, the opening of the bypass passage is usually used when starting the fuel cell. The opening may be performed only in one stage (usually fully open), but may be performed in a plurality of stages (typically multistage or infinite stage).

  The fuel cell system of the present invention includes the oxidizing gas channel system and the fuel cell.

  As for the flow path of the fuel gas, two three-way valves can be introduced similarly to the flow path of the oxidizing gas. However, a flow path configuration different from the oxidizing gas flow path is often adopted in the fuel gas flow path, such as a mechanism for reducing the fuel gas stored in the tank to an appropriate pressure.

  FIG. 1 is a diagram illustrating a schematic configuration of a fuel cell system according to the present embodiment. This diagram corresponds to FIG. 9, and the same components as those in FIG. The illustrated fuel cell system 10 includes an air system 12 and a fuel cell 204. The point that the air system 12 includes the supply path 206, the discharge path 208, the bypass path 210, and the humidification module 212 is the same as in the case of FIG. However, the fuel cell system 10 is not provided with the shut valves 214 and 216, the pressure regulating valve 218, and the bypass valve 220 included in the configuration of FIG. 9, but is provided with the three-way valves 14 and 16 instead. Yes.

  The three-way valve 14 is installed at a branch point between the supply path 206 and the bypass path 210, and determines how much air flowing from the upstream of the supply path 206 flows to the fuel cell 204 side and the bypass path 210 side. Similarly, the three-way valve 16 is installed at a branch point between the discharge path 208 and the bypass path 210 and determines how much air from the fuel cell 204 side and how much air from the bypass path 210 flows downstream of the discharge path 208. Has been decided. The control unit 18 is a device that controls each component of the fuel cell system 10 and can be constructed by using hardware having a calculation function and software (program) that defines the operation thereof. The three-way valves 14 and 16 are subjected to open / close control according to the operating state of the fuel cell 204 by the control unit 18.

  Subsequently, a configuration example of the three-way valve 14 will be described with reference to FIGS. 2 to 5. In each figure, the same number is attached | subjected to the structure same as FIG. 1, and description is simplified.

  FIG. 2 is a cross-sectional view of the three-way valve 14. The three-way valve 14 includes a rectangular parallelepiped hollow case 20, and an inlet pipe 22 connected to an upstream supply path is connected to three surfaces of the case 20 and a downstream (fuel cell side) supply path. An outlet pipe 24 and an outlet pipe 26 connected to the bypass are attached. A valve element 28 is attached to the shaft 30 in the case 20. The valve body 28 is driven by a stepping motor 32 and can change its position finely.

  For example, the valve body 28 can close the outlet pipe 24 and fully open the outlet pipe 26 as illustrated. At this time, all the air 34 flowing in from the inlet pipe 22 flows out as air 38 from the outlet pipe 26. Moreover, the valve body 28 is arrange | positioned in the position shown with the code | symbol 28b, and can each open the outlet pipes 24 and 26 halfway. At this time, the air 34 flowing in from the inlet pipe 22 is divided into air 36 flowing out from the outlet pipe 24 and air 38 flowing out from the outlet pipe 26. Further, the valve body 28 can be disposed at a position indicated by reference numeral 28c to fully open the outlet pipe 24 and close the outlet pipe 26. At this time, all the air 34 flowing in from the inlet pipe 22 flows out as air 36 from the outlet pipe 24.

  3 to 5 are perspective views showing these three states in the three-way valve 14. FIG. 3 shows a state in which the valve body 28 closes the outlet pipe 24. FIG. 4 shows a state in which the valve body 28 half-opens the outlet pipes 24 and 26, and FIG. 5 shows a state in which the valve body 28 closes the outlet pipe 26. 3 and 5, it is desirable that the amount of air leaking from the gap between the closed valve bodies 28 is as small as possible. Therefore, it is effective to provide a seal member for sealing a contact portion between the valve body 28 and the outlet pipes 24 and 26 on one or both of the valve body 28 and the outlet pipes 24 and 26. Further, in the state of FIG. 4, the valve body 28 receives a strong wind pressure by the air traveling straight from the inlet pipe 22, and thus a large torque acts on the base shaft. Therefore, when installing the valve body 28, it is necessary to ensure sufficient strength so that it can be stably fixed. Of course, the illustrated example is merely an example of the three-way valve 14, and this problem may be solved by adopting another configuration.

  Next, the flow control of the fuel cell system 10 shown in FIG. 1 will be described with reference to FIGS. In each figure, the same number is attached | subjected to the structure same as FIG. 1, and description is simplified.

  FIG. 6 is a diagram illustrating the flow control of the three-way valves 14 and 16 while the fuel cell 204 is stopped. In this state, the valve element 28 of the three-way valve 14 on the supply path 206 side is installed so as to close the supply path 206 toward the fuel cell 204 as shown in FIG. Similarly, in the three-way valve 16 on the discharge path 208 side, the valve body 50 is installed so as to close the fuel cell 204 side of the discharge path 208. Therefore, in this state, air is not supplied to the fuel cell 204. On the other hand, the path from the supply path 206 through the bypass path 210 to the discharge path 208 is open, and if the compressor on the upstream side of the supply path 206 is driven (usually stopped), the air is It is quickly discharged from the discharge path 208 via the bypass path 210.

  FIG. 7 is a diagram for explaining the flow control of the three-way valves 14 and 16 when the fuel cell 204 is started. At the time of start-up, the valve body 28 of the three-way valve 14 is arranged so that both the supply path 206 and the bypass path 210 toward the fuel cell 204 are half-opened as shown in FIG. Similarly, also in the three-way valve 16, the valve body 50 is disposed so as to half-open the fuel cell 204 side of the discharge path 208 and the bypass path 210. Therefore, a part of the air sent from the compressor on the upstream side of the supply path 206 is discharged after being supplied to the fuel cell 204, and the remaining air is quickly discharged through the bypass path 210.

  FIG. 8 is a diagram for explaining the flow control of the three-way valves 14 and 16 during operation of the fuel cell 204. During operation, the valve body 28 of the three-way valve 14 is in a state in which the bypass passage 210 is closed as shown in FIG. On the other hand, the valve body 50 of the three-way valve 16 is adjusted so that the fuel cell 204 side of the discharge path 208 and the bypass path 210 are half-opened. Therefore, in this state, all of the compressed air supplied from the supply path 206 flows into the fuel cell 204 and is discharged through the discharge path 208. However, the amount varies depending on how the discharge passage 208 is opened by the valve body 50. That is, the three-way valve 16 functions as a pressure regulating valve, and adjusts the amount of oxygen supplied according to the amount of power generated by the fuel cell 204. Instead of the control shown here, the three-way valve 14 may be operated as a pressure regulating valve, and the three-way valve 16 may close the bypass passage 210.

  In the above, typical control modes in each state of the fuel cell have been shown, but other flow control can be performed as necessary. For example, in a cold region, special flow control may be performed at the time of starting or stopping in order to cope with freezing in the fuel cell. In addition, when a malfunction occurs in one of the two three-way valves, desired control can be continued by mainly using the other three-way valve that operates normally. As such an example, in the operation state shown in FIG. 8, when a failure occurs in the pressure regulating valve function of the three-way valve 14, a mode in which the three-way valve 16 is operated as a pressure regulating valve instead can be given. .

It is the schematic which shows the structural example of a fuel cell system. It is sectional drawing which shows the structural example of a three-way valve | bulb. It is a perspective view which shows the operation | movement aspect of a three-way valve | bulb. It is a perspective view which shows the operation | movement aspect of a three-way valve | bulb. It is a perspective view which shows the operation | movement aspect of a three-way valve | bulb. It is a schematic diagram which shows the state at the time of a stop of a fuel cell. It is a schematic diagram which shows the state at the time of starting of a fuel cell. It is a schematic diagram which shows the state at the time of the driving | running of a fuel cell. It is the schematic which shows the reference structural example of a fuel cell system.

Explanation of symbols

  10,200 Fuel cell system, 12,202 Air system, 14,16 Three-way valve, 18 Control unit, 20 Case, 22 Inlet pipe, 24, 26 Outlet pipe, 28, 50 Valve body, 30 Shaft, 32 Stepping motor, 204 fuel cell, 206 supply path, 208 discharge path, 210 bypass path, 212 humidification module, 214, 216 shut valve, 218 pressure regulating valve, 220 bypass valve.

Claims (5)

A supply path for supplying oxidizing gas to the fuel cell;
An exhaust path for exhausting oxidizing gas from the fuel cell;
A bypass path that connects the path of the supply path and the path of the discharge path, and flows the oxidizing gas from the supply path to the discharge path;
A first three-way valve which is provided at a branch point between the supply path and the bypass path and adjusts the amount of oxidizing gas flowing into the fuel cell and the bypass path;
A second three-way valve that is provided at a branch point between the discharge passage and the bypass passage and adjusts the amount of oxidizing gas flowing out from the fuel cell and the bypass passage;
An oxidizing gas flow path system comprising: The oxidizing gas channel system according to claim 1,
The first three-way valve includes a mechanism that closes the supply path and does not supply the oxidizing gas to the fuel cell.
Alternatively, the second three-way valve is provided with a mechanism that closes the discharge path and does not discharge the oxidizing gas from the fuel cell. The oxidizing gas channel system according to claim 1,
The first three-way valve includes a mechanism that adjusts the amount of oxidizing gas flowing into the fuel cell in at least a plurality of stages.
Alternatively, the second three-way valve is provided with a mechanism for adjusting the amount of oxidizing gas flowing out from the fuel cell in at least a plurality of stages. The oxidizing gas channel system according to claim 1,
The first three-way valve includes a mechanism that closes the bypass passage and does not flow oxidizing gas through the bypass passage.
Alternatively, the second three-way valve is provided with a mechanism that closes the bypass passage and does not discharge the oxidizing gas from the bypass passage. The oxidizing gas flow path system according to any one of claims 1 to 4,
The fuel cell;
A fuel cell system comprising:

Images