JP3589221B2 - Fuel cell system - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel cell system that generates water by an electrochemical reaction and has improved drainage performance.
[0002]
[Prior art]
When a state in which water is excessively present in the gas passage in the fuel cell (hereinafter, referred to as water clogging), resistance of gas supply is caused, and power generation efficiency of the fuel cell is reduced.
[0003]
In order to prevent this, for example, in Japanese Patent Application Laid-Open No. H11-162489, a heat exchanger capable of exchanging heat between fuel gas and cooling water circulating by cooling the fuel cell is installed, and cooling water at the time of startup is provided. By switching the flow to the heat exchanger, before the humidified and heated fuel gas is supplied to the fuel cell, heat exchange is performed with cooling water that is still the temperature of the fuel cell to lower the temperature, A method has been adopted in which excess water vapor is condensed to prevent condensation in the fuel cell.
[0004]
[Problems to be solved by the invention]
However, in this conventional example, only preventing the water vapor contained at the time of startup from condensing, the water vapor remaining in the fuel cell at the time of the previous operation stop condenses as the fuel cell temperature decreases. Alternatively, the water vapor remaining in the fuel cell inlet / outlet pipe portion does not have a preventive effect against condensing and flowing into the fuel cell at the time of startup and causing water clogging. There is a problem that condensed water causes water clogging and causes a sudden drop in cell voltage, a desired output cannot be obtained, and in the worst case, the system must be stopped to protect the fuel cell from a drop in cell voltage. Was.
[0005]
In view of the above problems, an object of the present invention is to provide a fuel cell system capable of discharging not only condensed water and generated water during operation but also condensed water existing before startup, thereby preventing water clogging. That is.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 includes a fuel cell main body that generates power by an electrochemical reaction of a fuel gas and an oxidizing gas, a fuel gas supply unit that supplies a fuel gas to the fuel cell main body, In a fuel cell system including an oxidizing gas supply unit that supplies an oxidizing gas to a fuel cell body, water is temporarily stored in at least one of a fuel gas passage and an oxidizing gas passage of the fuel cell body. A water pool portion, a water guiding means for guiding water in the gas passage to the water pool portion, and a drain valve for draining water in the water pool portion, Pressure detecting means for detecting a pressure downstream of the drain valve, and estimating an amount of water in the gas passage based on a pressure change when the drain valve is opened detected by the pressure detecting means. That is the gist.
[0007]
In order to achieve the above object, the invention according to claim 2 is the fuel cell system according to claim 1, wherein the opening degree, the valve opening time, and the valve opening interval of the drain valve according to the amount of water in the gas passage. The gist is to adjust at least one of the above.
[0008]
In order to achieve the above object, according to a third aspect of the present invention, in the fuel cell system according to the first aspect, electric power taken out of the fuel cell main body is limited to a predetermined value or less according to an amount of water in the gas passage. That is the gist.
[0009]
According to a fourth aspect of the present invention, there is provided a fuel cell system according to the first aspect, wherein at least one of the fuel gas and the oxidizing gas is supplied according to an amount of water in the gas passage. The main point is to adjust the flow rate.
[0011]
Claims to achieve the above purpose 5 The invention described in the claims 1 In the fuel cell system described above, a gist is that a tank is provided downstream of the drain valve, and the pressure detecting means detects a pressure in the tank.
[0012]
Claims to achieve the above purpose 6 The invention described in claim 1 to claim 1 5 In the fuel cell system according to any one of the above, the gist of the invention is to drain the water in the water pool by opening the drain valve before taking out power from the fuel cell body at the time of startup.
[0013]
Claims to achieve the above purpose 7 The invention described in claim 1 to claim 1 6 The fuel cell system according to any one of claims 1 to 3, wherein the fuel cell main body includes a stack in which a plurality of cells are stacked, and the gas passage includes a manifold penetrating each cell, and a gas formed on an electrode surface in each cell. A flow path, and a connection hole for communicating a gas flow path formed on the manifold and the electrode surface in each cell, wherein the water guide means is inclined downward toward the water pool provided on the lower surface of the manifold. The gist is that there is.
[0014]
Claims to achieve the above purpose 8 The invention described in the claims 7 In the fuel cell system described above, a gist is that a lower surface of the manifold is lower than a lower end portion of the connection hole.
[0015]
Claims to achieve the above purpose 9 The invention described in the claims 8 In the fuel cell system according to the above aspect, a point is provided at the lower end of the connection hole so as to decrease toward the manifold.
[0016]
Claims to achieve the above purpose 10 The invention described in claim 1 to claim 1 9 In the fuel cell system according to any one of the above, the gist is that the water reservoir portion is provided near a connection portion of a gas pipe of the fuel gas or the oxidizing gas to the fuel cell main body.
[0017]
【The invention's effect】
According to the first aspect of the present invention, a fuel cell main body that generates electric power by an electrochemical reaction between a fuel gas and an oxidizing gas, a fuel gas supply unit that supplies a fuel gas to the fuel cell main body, and a fuel cell main body. A fuel cell system including an oxidizing gas supply unit configured to supply an oxidizing gas, wherein at least one of a fuel gas passage and an oxidizing gas passage of the fuel cell main body has a water reservoir for temporarily storing water. A water guiding means for guiding water in the gas passage to the water pool, and a drain valve for draining water in the water pool, Pressure detecting means for detecting a pressure downstream of the drain valve, and estimating an amount of water in the gas passage based on a pressure change when the drain valve is opened detected by the pressure detecting means. Because The condensed water remaining at the previous stop and the condensed water accumulated in the gas passage and the condensed water and generated water during operation are guided to the water reservoir by the water guiding means, and can be drained from the drain valve. Prevents water clogging in the gas passages not only during operation but also during operation, facilitates starting of the fuel cell, and enables stable operation of the cell voltage. At the same time, without providing a water amount detecting means in each of the water pools, the pressure detecting means provided in common downstream of each drain valve utilizes the fact that the pressure downstream of the drain valve changes according to the amount of water discharged. To estimate the amount of water This has the effect.
[0018]
According to the second aspect of the present invention, in the fuel cell system according to the first aspect, at least one of an opening degree, a valve opening time, and a valve opening interval of the drain valve according to an amount of water in the gas passage. Is adjusted, so that in addition to the effect of the invention described in claim 1, there is an effect that unnecessary valve opening is suppressed and effective drainage can be performed.
[0019]
According to the third aspect of the invention, in the fuel cell system according to the first aspect, the power taken out of the fuel cell main body is limited to a predetermined value or less according to the amount of water in the gas passage. In addition to the effects of the first aspect of the present invention, the fuel cell is configured to restrict the extraction of power to a predetermined value or less until the discharge of condensed water is completed, to suppress an increase in generated water, or to force extraction of power when the power generation efficiency decreases. This has the effect of preventing damage to the device.
[0020]
According to the fourth aspect of the present invention, in the fuel cell system according to the first aspect, the gas flow rate of at least one of the fuel gas and the oxidizing gas is adjusted according to the amount of water in the gas passage. As a result, in addition to the effect of the invention described in claim 1, there is an effect that when the amount of water is large, control such as blowing out water by increasing the gas flow rate becomes possible.
[0022]
Claim 5 According to the described invention, the claims 1 The fuel cell system according to claim 1, wherein a tank is provided downstream of the drain valve, and the pressure detecting means detects a pressure in the tank. 1 In addition to the effects of the described invention, there is an effect that the detection of the pressure downstream of the drain valve is facilitated, and the amount of water is easily estimated.
[0023]
Claim 6 According to the invention described in claims 1 to 1 5 The fuel cell system according to any one of claims 1 to 3, wherein the drain valve is opened before power is taken out from the fuel cell main body at the time of startup to drain the water in the water reservoir. 5 In addition to the effects of the described invention, water condensed in the fuel cell main body or in a gas pipe connected to the fuel cell main body can be discharged in advance, and a desired output can be taken out in a shorter time after startup. There is an effect that it becomes possible.
[0024]
Claim 7 According to the invention described in claims 1 to 1 6 The fuel cell system according to any one of claims 1 to 3, wherein the fuel cell main body includes a stack in which a plurality of cells are stacked, and the gas passage includes a manifold penetrating each cell, and a gas formed on an electrode surface in each cell. A flow path, a connection hole for communicating a gas flow path formed on the manifold and the electrode surface in each cell, wherein the water guide means is inclined toward the water pool provided on the lower surface of the manifold; Claims 1 to Claims 6 In addition to the effects of the described invention, there is an effect that the water can be automatically guided to the puddle portion by gravity without consuming energy for water guidance with a simple configuration.
[0025]
Claim 8 According to the described invention, the claims 7 The fuel cell system according to claim 1, wherein a lower surface of the manifold is lower than a lower end of the connection hole. 7 In addition to the effects of the described invention, there is an effect that water in the manifold hardly enters the electrode surface, and water on the electrode surface is easily discharged to the manifold, so that the performance of preventing water clogging can be improved.
[0026]
Claim 9 According to the described invention, the claims 8 In the fuel cell system described above, by providing the lower end of the connection hole with a slope that decreases toward the manifold, the effect of preventing water clogging can be further improved.
[0027]
Claim 10 According to the invention described in claims 1 to 1 9 In the fuel cell system according to any one of the above, the water reservoir is provided near a connection portion of a gas pipe of the fuel gas or the oxidant gas to the fuel cell main body, so that condensed water in the stack and There is no need to transport the generated water to a distance, which has the effect of shortening the water discharge time.
[0028]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view of a fuel cell stack 1 illustrating a first embodiment of a fuel cell system according to the present invention.
[0029]
In FIG. 1, a fuel cell stack 1, which is a fuel cell body that generates power by an electrochemical reaction of a fuel gas and an oxidant gas, has a solid polymer electrolyte membrane, an anode (fuel electrode) to which the fuel gas is supplied, and an oxidant, respectively. A plurality of fuel cells (hereinafter simply referred to as cells) 2 each having a cathode (oxidant electrode) to which gas is supplied are stacked.
[0030]
The plurality of cells 2 are fixed at both ends by being sandwiched between two end plates 3 (only one end is shown in FIG. 1). Further, a fuel gas supply pipe 4 for supplying a fuel gas, a fuel gas exhaust pipe for exhausting a fuel gas 5, an air supply pipe for supplying air as an oxidant gas, and air for exhausting air to the end plate 3. An exhaust pipe 7, a coolant supply pipe 8 for supplying a coolant, and a coolant discharge pipe 9 for discharging a coolant are connected respectively.
[0031]
The connection portions of the fuel gas supply pipe 4, the fuel gas exhaust pipe 5, the air supply pipe 6, and the air exhaust pipe 7 to the respective end plates 3 are condensed or generated from these pipes or from the fuel cell stack 1. A water reservoir 10 for temporarily storing condensed water and produced water is provided, and a drain pipe 12 is connected to the water reservoir 10 via an electromagnetic valve 11 which is a drain valve that opens and closes by an electric signal, and is collected in the water reservoir 10. The water can be drained.
[0032]
Then, a fuel gas is supplied from a fuel gas supply means (not shown) to the fuel gas supply pipe 4, and air is supplied from a compressor (not shown) serving as an oxidant gas supply means to the air supply pipe 6. As the fuel gas supply means, a means for supplying hydrogen gas from a fuel tank such as a high-pressure hydrogen tank via a decompressor is conceivable.
[0033]
In such a fuel cell system, since the function as a proton exchange membrane cannot be exhibited unless the polymer membrane is in a sufficiently wet state, some humidification method is used for the membrane. Among them, the most common method is a method in which only fuel gas or both fuel gas and air contain sufficient water vapor by humidifying means (not shown) and then supply the fuel gas to the fuel cell. Thereby, the polymer membrane is supplied with sufficient water to exhibit the function as a proton exchange membrane.
[0034]
FIG. 2 is a view showing an example of each flow path of the anode (a) and the cathode (b) of the bipolar plate used in the fuel cell 2 of the present invention.
[0035]
In the anode flow channel of FIG. 2A, a narrow fuel gas flow channel is formed on the electrode surface 21 by two interdigitated comb-shaped partitions. Fuel gas is supplied from an internal manifold 20a penetrating the stacked cells 2 via an electrode surface inlet (connection hole) 21a, and fuel gas is discharged to an internal manifold 20c via an electrode surface outlet (connection hole) 21b. It has become.
[0036]
Further, internal manifolds 20a and 20c for supplying and discharging gas are formed vertically long, and connection holes 21a and 21b serving as entrances and exits to the electrode surfaces are connected only to upper portions of the internal manifolds 20a and 20c, respectively. The lower surface of the manifold is lower than the lower end of the connection hole.
[0037]
In addition, since the lower surfaces of the connection holes 21a and 21b have an inclination A from the electrode surface entrance to the internal manifolds 20a and 20c, water condensed in the internal manifolds 20a and 20c hardly flows into the electrode surface 21, and Water condensed on the electrode surface 21 is easily discharged to the internal manifolds 20a and 20c.
[0038]
Similarly, in the cathode flow channel of FIG. 2B, a narrow air flow channel is formed on the electrode surface 22 by two intermeshing comb-shaped partition walls. Air is supplied from the internal manifold 20b penetrating the stacked cells 2 via the electrode surface inlet (connection hole) 22a, and air is discharged to the internal manifold 20d via the electrode surface outlet (connection hole) 22b. Has become.
[0039]
Further, internal manifolds 20b and 20d for supplying and discharging gas are formed to be vertically long, and connection holes 22a and 22b serving as entrances and exits to the electrode surfaces are connected only to upper portions of the internal manifolds 20b and 20d, respectively. The lower surface of the manifold is lower than the lower end of the connection hole.
[0040]
In addition, since the lower surfaces of the connection holes 22a and 22b have an inclination A from the electrode surface entrance to the internal manifolds 20b and 20d, water condensed in the internal manifolds 20b and 20d is unlikely to flow into the electrode surface 22, and Water condensed on the electrode surface 22 is easily discharged to the internal manifolds 20b and 20d.
[0041]
FIG. 3 is a cross-sectional view of the gas pipe and the internal manifold. As shown in FIG. 3, the lower surface of the internal manifold 20 of each cell 2 is inclined by gradually increasing the hole diameter toward the gas inlet. As a result, the condensed water and the generated water flow smoothly to the water reservoir 10 installed at the lowest position near the fuel cell stack 1 at the end plate 3 mounting portion of each of the gas pipes 4, 5, 6, and 7. It has become. An electromagnetic valve 11 is provided below the water reservoir 10, and discharges the water through a drainage pipe 12 of the water reservoir 10 by its operation.
[0042]
FIG. 4 is a system configuration diagram showing a configuration of a control system in the embodiment of the fuel cell system according to the present invention. In FIG. 4, downstream of the solenoid valve 11 installed below the water reservoir 10, the drain pipes 12a, 12b, 12c and 12d are respectively connected to the air system and the fuel gas system, and the air drain pipe 12e is provided. And a fuel gas drainage pipe 12f, which are connected to the air side water tank 13 and the fuel gas side water tank 14, respectively.
[0043]
The insides of these water tanks 13 and 14 are at atmospheric pressure when the solenoid valve 11 is closed by piping connected further downstream, and the pressure sensors 15 detect the tank internal pressure in the spaces where gas is stored. It has become. The pressure detected by the pressure sensor 15 is input to the control device 16, and operating conditions at the time of startup are determined according to the pressure.
[0044]
Here, the water accumulated in the air-side water tank 13 is collected and can be used again as humidifying water or the like.
[0045]
FIG. 5 is a time chart showing the relationship between the amount of discharged water and the internal pressure of the water tank. If the amount of water discharged by opening the solenoid valve 11 that is a drain valve periodically is large, the amount of water flowing in is relatively small with respect to the volume in the tank. Does not occur. When the discharge of the excess water is completed, the ratio of the flow of the fuel gas and the air when the electromagnetic valve 11 is opened increases, so that the pressure change increases. Thereby, it can be determined whether or not the discharge of the condensed water at the time of starting is completed.
[0046]
FIG. 6 is a time chart showing the relationship between the water tank internal pressure and the solenoid valve opening cycle, which is the cycle of opening the solenoid valve 11.
[0047]
The control device 16 shown in FIG. 4 determines that a large amount of condensed water remains when the internal pressure of the air-side water tank 13 or the fuel gas-side water tank 14 is less than Pl, and opens and closes the solenoid valve 11 at the shortest cycle Tmin. At the same time, the output of the fuel cell stack 1 is limited to be equal to or less than a predetermined value Lp. When the internal pressure of the water tank becomes equal to or higher than Pl, the opening cycle T of the solenoid valve 11 is sequentially increased to Ta, Tb,... According to the internal pressure value, and the output limit of the fuel cell stack 1 is set to Lp2 (Lp2>). Lp). When the internal pressure of the water tank exceeds Ph, it is determined that excess condensed water has been discharged, and the open cycle of the solenoid valve 11 is set to the longest value Tmax.
[0048]
FIG. 8 is a diagram showing a control flowchart of the solenoid valve opening cycle control. First, in step S10, in order to start the fuel cell, the power of a battery or the like is turned on, and power supply to the control device is started. Next, in step S12, the operation of the solenoid valve 11 for drainage is started with the open cycle T being the shortest cycle, and the drainage of the condensed water condensed in the fuel cell since the last stop is started. In step S14, the supply of the fuel gas and air to the fuel cell stack is started, and the circulation of the coolant is started. Next, in step S16, output taking out from the fuel cell stack is started, and in step S18, it is determined based on the temperature of the fuel cell main body, the gas supply pressure, and the like, whether or not normal operation of the fuel cell is possible. Move on to control of normal operation. If the normal operation is not possible, it is determined in step S20 whether or not the internal pressure P of the water tanks 13, 14 detected by the pressure sensor 15 is lower than the pressure set value Pl. If the internal pressure P is lower than the pressure set value Pl, in step S22, the output of the fuel cell stack is limited to the output limit value Lp [kW] or less, and the open cycle T of the drain solenoid valve 11 is set to the shortest cycle, and step S18. Return to
[0049]
If it is determined in step S20 that the internal pressure P is equal to or higher than the pressure set value Pl, it is determined in step S24 whether the internal pressure P is lower than the pressure set value Ph. If the internal pressure P is lower than the pressure set value Ph, in step S26, the output of the fuel cell stack is limited to the output limit value Lp2 [kW] or less, and the open cycle T of the drain solenoid valve 11 is set using the internal pressure P. The process returns to step S18 as a cycle of T = P × a + b (a and b are appropriate constants). If it is determined in step S24 that the internal pressure P is equal to or higher than the pressure set value Ph, in step S28, the output from the fuel cell stack due to the internal pressure P is removed, and the open cycle T of the drain valve 11 is set as the longest cycle. It returns to step S18.
[0050]
The pressure set values Pl and Ph for determining the internal pressures of the air-side water tank 13 and the fuel gas-side water tank 14 are the hydrogen gas concentration design value in the fuel gas, the shape of the gas passage, the shape of the drain pipe, and the water tank. Usually do not match and often differ depending on the capacity, etc. In this case, the detection value of the pressure sensor 15 for each individual water tank is compared with the set values of Pl and Ph, and the electromagnetic valve 11 for drainage provided in the air system piping and the fuel gas system are provided. The drainage solenoid valve 11 provided in the pipe is controlled for each system.
[0051]
Further, in the above flowchart, the opening period T of the solenoid valve is changed. However, the opening degree of the valve is similarly changed (shortening the cycle = increase the opening degree, increasing the cycle = decreasing the opening degree). ) Or the opening time of the valve may be changed (shorter the cycle = increase the opening degree, increase the cycle = decrease the opening degree).
[0052]
Also, at startup, the drain valve 11 is fully opened, and a condensed water discharge mode for supplying gas without taking out output from the fuel cell stack is performed, so that the discharge of condensed water is further promoted, and the fuel cell A desired output can be extracted from the stack.
[0053]
FIG. 9 shows a control flowchart at this time. First, in step S30, in order to start the fuel cell, the power of the battery or the like is turned on, and the power supply to the control device is started. Next, in step S32, all the drain valves 11 are held in the open state, and the condensed water condensed into the fuel cell after the last stop is drained. In step S34, supply of a predetermined amount of fuel gas and air to the fuel cell stack is started, and circulation of the coolant is started, and this state is maintained for a predetermined time. Next, when a predetermined time has elapsed in step S34, the open cycle T of the solenoid valve 11 for drainage is set to the shortest cycle in step S36. In step S38, the flow rates of the fuel gas and air to be supplied to the fuel cell stack are set to the starting flow rates, and the output extraction from the fuel cell stack is suspended.
[0054]
Next, in step S40, output is started from the fuel cell stack. In step S42, it is determined whether or not normal operation of the fuel cell is possible based on the temperature of the fuel cell body, the gas supply pressure, and the like. Move on to control of normal operation. If the normal operation is not possible, it is determined in step S44 whether or not the internal pressure P of the water tanks 13, 14 detected by the pressure sensor 15 is lower than the pressure set value Pl. If the internal pressure P is lower than the pressure set value Pl, in step S46, the output of the fuel cell stack is limited to the output limit value Lp [kW] or less, and the open cycle T of the drain solenoid valve 11 is set as the shortest cycle, and step S42 is performed. Return to
[0055]
If it is determined in step S44 that the internal pressure P is equal to or higher than the pressure set value Pl, it is determined in step S48 whether the internal pressure P is lower than the pressure set value Ph. If the internal pressure P is lower than the pressure set value Ph, in step S50, the output of the fuel cell stack is limited to the output limit value Lp2 [kW] or less, and the opening cycle T of the solenoid valve 11 for drainage is determined using the internal pressure P. The process returns to step S42 as a period of T = P × a + b (a and b are appropriate constants). If it is determined in step S48 that the internal pressure P is equal to or greater than the pressure set value Ph, in step S52, the output from the fuel cell stack is not limited by the internal pressure P, and the open cycle T of the drain valve 11 is set as the longest cycle. It returns to step S42.
[0056]
FIG. 7 shows an operation example in which the clogging of water is suppressed by using the electromagnetic valve 11 for drainage even during the normal operation. The operation of the solenoid valve 11 is almost the same as that at the time of startup, except that the operation enters the water clog clearing operation mode. In the water clog elimination operation mode, water clogging can be eliminated by blowing off water by increasing the flow rates of fuel gas and air to lower the gas utilization rate.
[0057]
FIG. 10 shows a flowchart at this time. First, in step S60, it is determined whether or not to stop the operation from the normal operation state, and if the operation is stopped, the process ends. If the operation is not stopped, it is determined in step S62 whether or not the internal pressure P of the water tanks 13, 14 detected by the pressure sensor 15 is lower than the pressure set value Pl. If the internal pressure P is lower than the pressure set value Pl, the opening cycle T of the drainage solenoid valve 11 is set to the shortest cycle in step S64, and the flow rates of the fuel gas and air are increased in step S66 (at this time, the gas utilization rate Decreases by c%), and returns to step S60.
[0058]
If it is determined in step S62 that the internal pressure P is equal to or greater than the pressure set value Pl, it is determined in step S68 whether the internal pressure P is lower than the pressure set value Ph. If the internal pressure P is lower than the pressure set value Ph, in step S72, the opening cycle T of the solenoid valve 11 for drainage is set to a cycle of T = P × a + b (a and b are appropriate constants) using the internal pressure P. Then, in step S74, the flow rates of the fuel gas and air are increased (at this time, the gas utilization rate decreases by d%), and the process returns to step S60.
[0059]
If it is determined in step S68 that the internal pressure P is equal to or higher than the pressure set value Ph, in step S70, the open cycle T of the drain valve 11 is set to the longest cycle, and the flow rates of the fuel gas and the air are returned to the normal flow rates. It returns to step S60.
[0060]
Next, a second embodiment of the fuel cell system according to the present invention will be described. In the first embodiment, the water reservoir and the solenoid valve are provided near the supply gas pipe mounting portion outside the end plate. In the second embodiment, an example in which the water reservoir is provided inside the end plate will be described. .
[0061]
As shown in FIGS. 11 and 12, in the second embodiment, an end plate 30 having a water reservoir portion provided with a water reservoir portion 31 inside the end plate, and an electromagnetic valve block 32 in which electromagnetic valves are integrated with the end plate 30. Is attached. According to this embodiment, the fuel cell stack can be reduced in size, and the mechanical strength can be improved.
[0062]
In addition to the above embodiments, the inclination of the lower surface of the manifold toward the water pool may be configured by a method of inclining the manifold itself or a method of installing the stack inclining.
[Brief description of the drawings]
FIG. 1 is a perspective view of a fuel cell stack 1 illustrating a first embodiment of a fuel cell system according to the present invention.
FIG. 2 is a diagram showing an example of each flow path of an anode (a) and a cathode (b) of a bipolar plate used in the fuel cell 2 of the present invention.
FIG. 3 is a cross-sectional view of a gas pipe and an internal manifold according to the first embodiment.
FIG. 4 is a system configuration diagram showing a configuration of a control system in an embodiment of the fuel cell system according to the present invention.
FIG. 5 is a time chart illustrating a relationship between a water discharge amount and a water tank internal pressure.
FIG. 6 is a time chart showing the relationship between the water tank internal pressure and the solenoid valve opening cycle, which is the cycle of opening the solenoid valve 11;
FIG. 7 is a time chart illustrating an operation example in which water clogging is suppressed by using the electromagnetic valve 11 for drainage during normal operation.
FIG. 8 is a diagram illustrating a control flowchart of a solenoid valve opening cycle at the time of startup in the embodiment.
FIG. 9 is a diagram illustrating a control flowchart of a solenoid valve opening cycle at the time of startup in the embodiment.
FIG. 10 is a diagram showing a control flowchart in a case where water clogging is suppressed by using a drainage electromagnetic valve even during normal operation.
FIG. 11 is a cross-sectional view of a gas pipe and an internal manifold according to a second embodiment.
FIG. 12 is a perspective view illustrating a configuration of a fuel cell stack according to a second embodiment.
[Explanation of symbols]
1. Fuel cell stack
2… cell
3 ... End plate
4: Fuel gas supply pipe
5. Fuel gas exhaust pipe
6. Air supply piping
7… Air exhaust piping
8. Coolant supply piping
9 ... Coolant discharge piping
10 ... water pool
11 ... solenoid valve (drain valve)
12 ... Drain pipe

Claims (10)

A fuel cell body that generates power by an electrochemical reaction of a fuel gas and an oxidant gas,
Fuel gas supply means for supplying fuel gas to the fuel cell body;
An oxidizing gas supply unit for supplying an oxidizing gas to the fuel cell body,
In at least one gas passage of the fuel gas passage and the oxidizing gas passage of the fuel cell body,
A water pool for temporarily storing water,
Water guiding means for guiding water in the gas passage to the water reservoir,
A drain valve for draining the water in the water reservoir,
Pressure detection means for detecting the pressure downstream of the drain valve,
With
The fuel cell system according to claim 1, wherein an amount of water in said gas passage is estimated based on a pressure change when said drain valve is opened detected by said pressure detecting means. 2. The fuel cell system according to claim 1, wherein at least one of an opening degree, a valve opening time, and a valve opening interval of the drain valve is adjusted according to an amount of water in the gas passage. The fuel cell system according to claim 1, wherein electric power taken out of the fuel cell main body is limited to a predetermined value or less according to an amount of water in the gas passage. 2. The fuel cell system according to claim 1, wherein a gas flow rate of at least one of the fuel gas and the oxidizing gas is adjusted according to an amount of water in the gas passage. A tank is provided downstream of the drain valve,
It said pressure detecting means, the fuel cell system according to claim 1, wherein the detecting the pressure in the tank. The fuel cell system according to any one of claims 1 to 5 , wherein the drain valve is opened to drain the water from the water pool portion before power is taken out from the fuel cell body at the time of startup. The fuel cell body includes a stack in which a plurality of cells are stacked,
The gas passage,
A manifold penetrating each cell,
A gas flow path formed on the electrode surface in each cell,
A connection hole that communicates a gas passage formed on the manifold and the electrode surface in each cell is provided,
The fuel cell system according to any one of claims 1 to 6 , wherein the water guiding means has a slope that decreases toward the water pool provided on the lower surface of the manifold. The fuel cell system according to claim 7 , wherein a lower surface of the manifold is lower than a lower end of the connection hole. 9. The fuel cell system according to claim 8 , wherein a slope that decreases toward the manifold is provided at a lower end of the connection hole. The fuel cell according to any one of claims 1 to 9 , wherein the water reservoir is provided near a connection portion of a gas pipe of the fuel gas or the oxidizing gas to the fuel cell main body. system.

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