JP2006100238A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system capable of reducing pressure loss by passing a fluid in an impurity remover and of improving the service life of the impurity remover. <P>SOLUTION: This fuel cell system 1 is so structured that the impurity remover 24 for removing impurities mixed in a discharged fluid is installed in a discharge passage 19 for running the discharged fluid discharged from a fuel cell 10 therethrough; is provided with a bypass passage 22 bypassed from the discharge passage 19, and a fluid inflow control part 20 disposed on the upstream side of the bypass passage 22 for controlling the volume of the discharged fluid flowing into the bypass passage 22 and the discharge passage 19; and is composed by installing the impurity remover 24 in the bypass passage 22. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell system, and more particularly to a fuel cell system in which an impurity remover that removes impurities mixed in the fluid is disposed in a discharge passage through which a fluid discharged from the fuel cell flows.

  2. Description of the Related Art Conventionally, there is a fuel cell system in which an impurity remover that removes impurities mixed in the fluid is disposed in a discharge passage through which a fluid discharged from the fuel cell flows. In this fuel cell system, not all of the supplied hydrogen is used for the cell reaction. Therefore, a circulation system is used in which the discharged unreacted hydrogen is returned to the fuel cell for effective use. The exhaust gas discharged from the fuel cell and the water generated by the cell reaction of the fuel cell ( A gas-liquid separator for removing water from the gas-liquid mixed fluid that is mixed with the product water is provided.

  Here, in the gas and water flowing in the hydrogen circulation system, there are a small amount of impurities eluted from the fuel cell and the piping parts of the system. Impurities may also enter from the air sucked from the outside air of the cathode system and pass through the electrolyte membrane and enter the hydrogen circulation system. In particular, when metal ions are present in impurities eluted from fuel cell or piping parts of the system, there is a risk of reducing the function and life of the fuel cell itself. Moreover, the water produced | generated within a fuel cell may become acidic. Therefore, conventionally, a method has been adopted in which an ion exchanger is provided in the hydrogen circulation system to suppress deterioration of the fuel cell due to generated water, gas, or the like.

In recent years, a polymer electrolyte fuel is provided on the polymer electrolyte fuel cell side of at least one discharge pipe from which the generated water of the fuel cell is discharged, and removes ions contained in the generated water accompanying the exhaust gas. A battery system is introduced. In this polymer electrolyte fuel cell system, it is disclosed that an ion exchange resin is used to remove fluorine ions as means for removing ions contained in the generated water. (For example, refer to Patent Document 1).
JP 2002-313404 A

  However, the polymer electrolyte fuel cell system described in Patent Document 1 separates a fluid (gas-liquid mixture) into a liquid and a gas, and then passes the separated liquid through an ion exchange resin. Although the impurities are removed from the liquid, the ion exchange resin is configured such that all of the liquid passes through regardless of the content of impurities contained in the separated liquid. Therefore, pressure loss caused by passing through the ion exchange resin may cause loss in the hydrogen circulation system and shorten the life.

  It is an object of the present invention to improve such a conventional fuel cell system, and can reduce pressure loss caused by the fluid passing through the impurity remover, and the lifetime of the impurity remover. An object of the present invention is to provide a fuel cell system capable of improving the fuel efficiency.

  In order to achieve this object, the present invention is a fuel cell system in which an impurity remover for removing impurities mixed in the exhaust fluid is disposed in an exhaust passage through which the exhaust fluid discharged from the fuel cell flows. A branch passage branched from the discharge passage, and a fluid inflow control means disposed upstream of the branch passage and controlling the amount of the exhaust fluid flowing into the branch passage and the discharge passage. A fuel cell system in which the impurity remover is disposed in the branch passage is provided.

  In the fuel cell system having this configuration, the amount of exhaust fluid flowing into the branch passage and the amount of exhaust fluid flowing into the discharge passage among the exhaust fluid discharged from the fuel cell are controlled by the fluid inflow amount control means. can do. Therefore, since only the exhaust fluid that needs to pass through the impurity remover can flow into the branch passage and pass through the impurity remover, the pressure loss caused by the exhaust fluid passing through the impurity remover can be reduced. Can be reduced. Further, since the amount of the exhaust fluid passing through the impurity remover can be reduced, the life of the impurity remover can be improved.

  The branch passage corresponds to a sub-discharge passage arranged in parallel with the main discharge passage when the discharge passage is used as a main discharge passage, and its downstream side joins the main discharge passage again. It is not necessary to join the main discharge passage.

  The fluid inflow amount control means may include an on-off valve that allows the discharged fluid to flow into at least one of the branch passage and the discharge passage.

  Further, the fluid inflow amount control means can control the amount of discharged fluid flowing into the branch passage and the discharge passage according to a value determined by the operating state of the fuel cell.

  The value determined by the operating state of the fuel cell can be the state quantity of the exhaust fluid. Examples of the state quantity of the discharged fluid include at least one of conductivity, pressure, flow rate, pH, and ion concentration of the discharged fluid, or a combination thereof.

  The value determined by the operating state of the fuel cell may be a value based on an operating state of a pump that sucks the exhaust fluid.

  Further, the value determined by the operating state of the fuel cell may be a value based on the power generation state of the fuel cell.

  In the fuel cell system according to the present invention, an impurity removing unit may be further disposed on the discharge passage downstream of the branch passage and upstream of the branch passage. In this case, the capacity of the impurity remover disposed in the discharge passage may be configured to be smaller than the capacity of the impurity remover disposed in the branch passage.

  In addition, when an impurity removing unit is provided in both the branch passage and the discharge passage, the fluid inflow control means is configured to change the branch passage and the discharge passage according to the capacity of the impurity remover. It can also be configured to control the amount of exhaust fluid flowing into the.

  Furthermore, the present invention is a fuel cell system in which an impurity remover for removing impurities mixed in the fuel gas is disposed in a circulation passage through which the fuel gas discharged from the fuel cell flows. A branch passage branched from the passage, and a fluid inflow amount control means arranged upstream of the branch passage and controlling the amount of fuel gas flowing into the branch passage and the circulation passage, and removing the impurities A fuel cell system in which a vessel is disposed in the branch passage is provided.

  A fuel cell system having this configuration flows into a branch passage in a circulation system in which unreacted fuel gas discharged from the fuel cell (hereinafter referred to as “circulation fuel gas”) is returned to the fuel cell and used effectively. The amount of the circulating fuel gas and the amount of the circulating fuel gas flowing into the circulation passage can be controlled by the fluid inflow amount control means. Accordingly, since only the circulating fuel gas that needs to pass through the impurity remover can flow into the branch passage and pass through the impurity remover, the pressure loss caused by the fuel gas passing through the impurity remover Can be reduced. In addition, since the amount of fuel gas passing through the impurity remover can be reduced, the life of the impurity remover can be improved.

  The branch passage corresponds to a sub-circulation passage arranged in parallel to the main circulation passage when the circulation passage is used as the main passage, and the downstream side may be joined to the main circulation passage again. Alternatively, it may be connected to the fuel gas inlet of the fuel cell without joining the main circulation passage. In addition, a supply path for new fuel gas supplied from a fuel gas supply source is joined to the circulation path, and the new fuel gas also circulates together with the circulation fuel gas. Therefore, the circulation passage is also a fuel gas supply passage for supplying fuel gas to the fuel cell.

  The fluid inflow amount control means may include an on-off valve that allows the circulating fuel gas to flow into at least one of the branch passage and the circulation passage.

  Further, the fluid inflow amount control means can control the amount of circulating fuel gas flowing into the branch passage and the circulation passage according to a value determined by the operating state of the fuel cell.

  The value determined by the operating state of the fuel cell can be the state quantity of the circulating fuel gas. Examples of the state quantity of the circulating fuel gas include at least one of the flow rate, conductivity, pressure, pH, and the like of the circulating fuel gas, or a combination thereof.

  Further, the value determined by the operating state of the fuel cell may be a value based on an operating state of a pump that sucks the circulating fuel gas.

  Further, the value determined by the operating state of the fuel cell may be a value based on the power generation state of the fuel cell.

  In the fuel cell system according to the present invention, an impurity removing unit may be further disposed on the circulation path downstream from the branch point of the branch path and upstream from the junction point of the branch path. In this case, the capacity of the impurity remover disposed in the circulation path may be configured to be smaller than the capacity of the impurity remover disposed in the branch path.

  In addition, when an impurity removing unit is provided in both the branch passage and the circulation passage, the fluid inflow control means is configured so that the branch passage and the circulation passage correspond to the capacity of the impurity remover. It can also be configured to control the amount of exhaust fluid flowing into the.

  The fuel cell system according to the present invention controls the amount of exhaust fluid flowing into the branch passage and the amount of exhaust fluid flowing into the discharge passage among the exhaust fluid discharged from the fuel cell by the fluid inflow amount control means. As a result, only the exhaust fluid that needs to be passed through the impurity remover can flow into the branch passage and pass through the impurity remover. Therefore, the pressure loss caused by the exhaust fluid passing through the impurity remover can be reduced, and the lifetime of the impurity remover can be improved.

  The fuel cell system according to the present invention can control the amount of the circulating fuel gas flowing into the branch passage and the amount of the circulating fuel gas flowing into the circulation passage by the fluid inflow amount control means, thereby removing impurities. Since only the circulating fuel gas that needs to pass through the vessel can flow into the branch passage and pass through the impurity remover, the pressure loss caused by the fuel gas passing through the impurity remover is reduced. Can do. In addition, since the amount of fuel gas passing through the impurity remover can be reduced, the life of the impurity remover can be improved.

  Next, a fuel cell system according to a preferred embodiment of the present invention will be described with reference to the drawings. In addition, embodiment described below is the illustration for demonstrating this invention, and this invention is not limited only to these embodiment. Therefore, the present invention can be implemented in various forms without departing from the gist thereof.

(Embodiment 1)
FIG. 1 is a schematic configuration diagram of a fuel cell system according to Embodiment 1 of the present invention, and FIG. 2 is a diagram showing conductivity of exhaust gas discharged from the fuel cell shown in FIG. 1 and contained in the exhaust gas. FIG. 3 is a flowchart showing the operation of the fluid inflow control unit shown in FIG. 1.

  The fuel cell 10 of the fuel cell system 1 shown in FIG. 1 supplies MEA, fuel gas (hydrogen) to the fuel electrode (anode) of the MEA, and oxidant gas (oxygen, usually air) to the oxidant electrode (cathode). In this configuration, a stack including a plurality of stacked cells and a separator that forms a flow path for performing the above operation is provided.

  An air supply source 9 for supplying air as an oxidizing gas is connected to the air supply port 11 of the fuel cell 10 via an air supply passage 12, and the air discharge port 13 is discharged from the fuel cell 10. An air discharge passage 14 through which discharged air and water (exhaust fluid) are discharged is connected. The air supply passage 12 and the air discharge passage 14 are provided with a humidification module 8, and the exhaust fluid that has passed through the humidification module 8 is discharged to the outside through the muffler 7. Further, a part of the discharged fluid is supplied to the hydrogen diluter 6, used for diluting hydrogen, and then discharged to the outside.

  On the other hand, a hydrogen supply source 16 such as a hydrogen cylinder is connected to the hydrogen supply port 15 of the fuel cell 10 via a hydrogen supply passage 17, and a hydrogen discharge passage 19 is connected to the hydrogen discharge port 18. Has been.

  The hydrogen discharge passage 19 is provided with a conductivity meter 21 for measuring the conductivity of the discharged fluid (hydrogen and water) discharged from the fuel cell 10. At a branch point A downstream of the position where the conductivity meter 21 of the hydrogen discharge passage 19 is disposed, a bypass passage 22 as a branch passage is formed by branching from the hydrogen discharge passage 19. An impurity remover 24 is disposed in the middle of the bypass passage 22 via an on-off valve 23. In the first embodiment, an ion exchanger is used as the impurity remover 24.

  On the other hand, the downstream of the hydrogen discharge passage 19 in which the bypass passage 22 is formed is connected to a gas-liquid separator 26 via an on-off valve 25. In the first embodiment, the conductivity meter 21 and the open / close valves 23 and 25 cause the amount of the exhaust fluid flowing into the bypass passage 22 and the exhaust flowing downstream from the branch point A of the hydrogen discharge passage 19. A fluid inflow control unit 20 that controls the amount of fluid is configured. In the first embodiment, a cyclone gas-liquid separator that separates gas and liquid by rotating a fluid (gas-liquid mixture) is used as the gas-liquid separator 26.

  The downstream of the bypass passage 22 that has passed through the impurity remover 24 is joined at a junction B downstream of the on-off valve 25 of the hydrogen discharge passage 19 and upstream of the gas-liquid separator 26. The gas (hydrogen) separated into gas (hydrogen) and liquid (water) by the gas-liquid separator 26 is supplied again to the fuel cell 10 from the hydrogen supply passage 17 and used for the cell reaction. Further, the gas (hydrogen) discharged from the gas-liquid separator 26 is supplied to the hydrogen diluter 6 as desired. Reference numeral 27 denotes a hydrogen pump.

  In the fluid inflow control unit 20, the conductivity of the discharged fluid (mixed fluid of hydrogen and water) discharged from the fuel cell 10 to the hydrogen discharge passage 19 is measured by the conductivity meter 21. Here, as shown in FIG. 2, a proportional relationship is established between the conductivity of the discharged fluid and the amount of impurities contained in the discharged fluid. Therefore, by measuring the conductivity of the discharged fluid, it can be determined how much impurities are contained in the discharged fluid, and whether this content is the amount of impurities to be removed by the impurity remover 24. It can be determined whether or not.

  Specifically, as shown in FIG. 3, the conductivity of the discharged fluid discharged into the hydrogen discharge passage 19 is measured by a conductivity meter 21. (Step S101). Next, when the electrical conductivity obtained in step S101 exceeds a preset threshold value (step S102: YES), it is determined that impurities should be removed by passing the discharged fluid through the impurity remover 24. Then, the on-off valve 25 is closed and the on-off valve 23 is opened (step S103), and the discharged fluid is supplied to the bypass passage 22. On the other hand, if the conductivity obtained in step S101 does not exceed a preset threshold value (step S102: NO), it is determined that the discharged fluid does not have to pass through the impurity remover 24, The on-off valve 23 is closed and the on-off valve 25 is opened (step S104), and the exhaust fluid is supplied to the downstream side of the hydrogen discharge passage 19.

  In this way, not all of the exhaust fluid discharged from the fuel cell 10 is passed through the impurity remover 24, but only the exhaust fluid that needs to pass through the impurity remover 24 is allowed to pass through the impurity remover 24. Since the amount of the exhaust fluid passing through the impurity remover 24 can be reduced, pressure loss can be reduced and the lifetime of the impurity remover 24 can be improved.

  As described above, the exhaust fluid that has passed through the bypass passage 22 is removed from the impurities contained therein by the impurity remover 24, and then joined to the hydrogen discharge passage 19 at the junction B. It is supplied to the separator 26. On the other hand, the exhaust fluid passing only through the hydrogen discharge passage 19 is also supplied to the gas-liquid separator 26.

  In the first embodiment, the case where the conductivity meter 21 is arranged on the upstream side of the impurity remover 24 has been described. However, the present invention is not limited to this, and as shown in FIG. A conductivity meter 30 may be provided. With this configuration, the conductivity of the exhaust fluid passing through the upstream side of the impurity remover 24 can be compared with the conductivity of the exhaust fluid passing through the downstream side. The removal ability can be detected. Therefore, the lifetime of the impurity remover 24 can also be detected.

  In the first embodiment, the humidification state of the MEA of the fuel cell 10 can be known by the conductivity meter 21. That is, when the MEA is dry and the amount of generated water is low, the conductivity of the exhaust fluid discharged from the fuel cell 10 increases, and when the amount of generated water is high and the MEA is moist, the conductivity tends to decrease. It is in. Therefore, by measuring the electrical conductivity of the discharged fluid, as described above, it is possible to grasp the operating state of the fuel cell 10 in addition to controlling the opening and closing of the on-off valves 23 and 25.

  In the first embodiment, a conductivity meter 21 is provided as one of the components of the fluid inflow control unit 20, and the bypass passage is based on the conductivity of the discharged fluid discharged to the hydrogen discharge passage 19. Although the case where it is determined whether to supply the exhaust fluid to 22 or to supply the exhaust fluid downstream from the branch point A of the hydrogen discharge passage 19 has been described, not limited to this, instead of the conductivity meter 21, A pressure gauge for measuring the pressure of the discharged fluid discharged into the hydrogen discharge passage 19 is provided, and the opening and closing valves 23 and 25 are controlled based on the pressure measured by the pressure gauge, and the discharged fluid is supplied to the bypass passage 22. It may be determined whether to supply the exhaust fluid downstream of the branch point A of the hydrogen discharge passage 19. In this case, for example, the hydrogen flow rate may be calculated based on the hydrogen tank pressure drop rate as the hydrogen supply source 16, and the opening and closing of the on-off valves 23 and 25 may be controlled based on this flow rate.

  Further, instead of the conductivity meter 21, a pH measuring device for measuring the pH of the discharged fluid discharged into the hydrogen discharge passage 19 is provided, and the opening and closing valves 23 and 25 are opened and closed based on the pH measured by the pH measuring device. May be controlled to determine whether to supply the exhaust fluid to the bypass passage 22 or to supply the exhaust fluid downstream of the branch point A of the hydrogen discharge passage 19.

  Further, as shown in FIG. 5, instead of the conductivity meter 21, a flow meter 31 for measuring the flow rate of the discharged fluid discharged into the hydrogen discharge passage 19 is provided, and based on the flow rate measured by the flow meter 31. The opening / closing valves 23 and 25 may be controlled to determine whether to supply exhaust fluid to the bypass passage 22 or to supply exhaust fluid downstream of the branch point A of the hydrogen discharge passage 19. In this case, instead of the flow meter 31, a flow meter 32 may be provided on the upstream side of the hydrogen supply passage 17, and the flow meter on the downstream side of the junction C with the hydrogen discharge passage 19 of the hydrogen supply passage 17. 33 may be provided.

  Furthermore, instead of the conductivity meter 21, a power generation state measurement meter for measuring the power generation state of the fuel cell 10 is provided, and the opening and closing valves 23 and 25 are opened and closed based on values obtained from the power generation state measurement meter. You may control. Examples of the power generation state of the fuel cell 10 include various factors such as power generation amount and power generation time. For example, an output meter that measures the output (current value, etc.) of the fuel cell 10 may be provided instead of the conductivity meter 21, and the opening / closing of the on-off valves 23 and 25 may be controlled based on the output of the fuel cell 10. . Further, instead of the conductivity meter 21, a rotational speed measuring meter for measuring the rotational speed of the hydrogen pump 27 is provided, and the opening and closing valves 23 and 25 are opened and closed based on the rotational speed measured by the rotational speed measuring meter. You may control.

  When the load of the fuel cell is measured and the opening / closing of the on-off valves 23 and 25 is controlled based on the measured load, for example, as shown in FIG. 8, the relationship between the fuel cell load and the circulating hydrogen flow rate as the circulating fuel gas Therefore, the circulating hydrogen flow rate may be calculated and the opening / closing of the on-off valves 23 and 25 may be controlled based on this.

  FIG. 9 is a view showing the relationship between the discharged fluid (circulated hydrogen flow rate) discharged to the hydrogen discharge passage 19 and the pressure loss. From FIG. 9, the discharged fluid is supplied to the bypass passage 22 at a predetermined timing. It can be seen that the pressure loss in this case is smaller than the pressure loss when all of the discharged fluid discharged to the hydrogen discharge passage 19 is passed through the impurity remover 24.

  Further, it can be seen that the relationship between the fuel cell load and the ion concentration of the discharged fluid is in an inversely proportional relationship as shown in FIG. In this case, the open / close state of the open / close valves 23 and 25 can be determined by whether or not a predetermined boundary target value (threshold value) has been exceeded. That is, when the ion concentration exceeds the boundary target value, the opening / closing of the on-off valves 23 and 25 may be controlled so that the discharged fluid passes through the impurity remover 24.

  In the first embodiment, the case where the impurity remover 24 is disposed in the bypass passage 22 has been described. However, the present invention is not limited to this, and as shown in FIG. An impurity remover 34 may be disposed between the two. As the impurity remover 34, one having a smaller capacity than the impurity remover 24 was used. Thus, by providing the impurity remover 34, for example, when the fuel cell 10 has a low output, the flow rate of the discharged fluid discharged from the fuel cell 10 is small (the processing amount is small). When the fuel cell 10 is supplied to the discharge passage 19 and passed through the impurity remover 34 having a small capacity and the fuel cell 10 has a high output, the flow rate of the discharged fluid discharged from the fuel cell 10 is large (the processing amount is large). It can be supplied to the bypass passage 22 and passed through the impurity remover 24 having a large capacity, and the pressure loss can be reduced to prevent an increase in circulation system power such as the hydrogen pump 27.

  When the impurity remover 34 is provided, the amount of the exhaust fluid supplied downstream from the branch point A of the bypass passage 22 and the hydrogen discharge passage 19 is controlled according to the capacity of the impurity removers 24 and 34. You may make it do.

  Here, since the amount of fluid discharged from the hydrogen circulation system determines the necessary hydrogen circulation amount based on the output (current value, etc.) of the fuel cell 10, it depends on the output of the fuel cell 10 or the rotational speed of the hydrogen pump 27. The amount of hydrogen circulation will be determined. Further, as the output of the fuel cell 10 increases, the amount of generated water increases. That is, L = C × I. (However, L is the amount of produced water, C is an eigen constant by the stack of fuel cells, and I is a current value). Therefore, when the fuel cell 10 has a low output, the flow rate of the discharged fluid discharged from the fuel cell 10 is small, and when the fuel cell 10 has a high output, the flow rate of the discharged fluid discharged from the fuel cell 10 is large.

  Further, in the first embodiment, one of the on-off valves 23 and 25 is controlled to be opened and the other is closed, and the discharged fluid is supplied to the bypass passage 22 or the hydrogen discharge passage 19 is not passed through the bypass passage 22. However, the present invention is not limited to this. Exhaust fluid is supplied to the bypass passage 22 and the downstream side of the branch point A of the hydrogen discharge passage 19 in arbitrary amounts. Thus, the open / close state of the open / close valves 23 and 25 may be controlled. For example, as an example, when about 70% of the discharged fluid is supplied to the bypass passage 22 and about 30% is supplied downstream from the branch point A of the hydrogen discharge passage 19, the open / close state of the on-off valves 23 and 25 (the passage is The amount of discharged fluid supplied to the downstream of the bypass passage 22 and the branch point A of the hydrogen discharge passage 19 may be arbitrarily determined.

  The amount of the discharge fluid supplied downstream from the branch point A of the bypass passage 22 and the hydrogen discharge passage 19 can be determined by the capacity of the impurity removers 24 and 34, for example.

  Further, in the fuel cell system according to the present invention, when the amount of exhaust fluid discharged from the fuel cell 10 increases at the time of high output of the fuel cell 10, the on-off valve is used to reduce the pressure loss. It is conceivable to open both of the openings 23 and 25. In this case, the discharged fluid tends to flow downstream from the branch point A of the hydrogen discharge passage 19 rather than the bypass passage 22. Therefore, it is conceivable that the lifetime of the impurity remover 34 having a small capacity is reduced.

  Therefore, as a countermeasure, for example, as shown in FIG. 7, a bypass passage 44 for bypassing the upstream of the on-off valve 25 to the downstream of the on-off valve 25 is further formed, the on-off valve 23 is opened, and the on-off valve 25 is closed. , The exhaust fluid is bypassed to the bypass passage 44. At this time, the bypass passage 44 has an inner diameter that is determined (calculated) depending on the amount of discharged fluid to be supplied to the bypass passage 22 and the amount of discharged fluid to be supplied downstream from the branch point A of the hydrogen discharge passage 19. it can. Alternatively, a restriction (orifice) having a desired diameter is formed in the bypass passage 44 or an on-off valve is provided in the bypass passage 44 to supply the bypass passage 22 and the hydrogen discharge passage 19 downstream from the branch point A. The balance of the amount of discharged fluid to be determined can be arbitrarily determined.

  By doing in this way, when both the on-off valves 23 and 25 are opened, pressure loss can be reduced and deterioration of the impurity remover 34 can be prevented. Further, when the output of the fuel cell 10 is low, the on-off valve 25 is open, and if compatibility with the impurity remover 34 is taken in this state, there is no influence due to the formation of the bypass passage 44.

  In the first embodiment, the case where the on-off valve 23 is provided in the bypass passage 22 and the on-off valve 25 is provided in the hydrogen discharge passage 19 has been described. A three-way valve may be provided at the branch point A, and the amount of the exhaust fluid supplied to the bypass passage 22 and the amount of the exhaust fluid supplied to the hydrogen discharge passage 19 may be controlled by the three-way valve.

  In the first embodiment, the bypass passage 22 is formed as a branch passage branched from the hydrogen discharge passage 19, and the bypass passage 22 is joined again to the hydrogen discharge passage 19 at the junction B. However, the present invention is not limited to this, and the branch passage may not be merged with the hydrogen discharge passage 19 again.

  Furthermore, in the first embodiment, the case where the impurity removers 24 and 34 are disposed in the hydrogen circulation system has been described. However, the present invention is not limited to this, and the impurity removers 24 and 34 according to the present invention may be an oxidizing gas (air ) You may arrange | position in a supply system or a discharge system, and may arrange | position in another piping system.

  For example, when a bypass passage is formed in the oxidant gas (air) discharge system and an impurity remover is provided, a configuration as shown in FIG. 11 can be adopted. That is, a conductivity meter 21 is disposed on the downstream side of the humidification module 8 in the air discharge passage 14, and at a branch point C on the downstream side of the position where the conductivity meter 21 of the air discharge passage 14 is disposed, A bypass passage 122 as a branch passage is formed by branching from the air discharge passage 14. An impurity remover 24 is provided in the middle of the bypass passage 122 via an on-off valve 23.

  On the other hand, the downstream side of the branch point C of the air discharge passage 14 is connected to the gas-liquid separator 26 via the on-off valve 25. Then, in the same manner as described above, the amount of the exhaust fluid flowing into the bypass passage 122 and the amount of the exhaust fluid flowing downstream from the branch point C of the air discharge passage 14 by the conductivity meter 21 and the on-off valves 23 and 25. A fluid inflow amount control unit 20 that controls the amount is configured.

  The downstream side of the bypass passage 122 from the impurity remover 24 is joined at a junction point D downstream of the on-off valve 25 of the air discharge passage 14. A gas-liquid separator 26 is disposed downstream of the confluence point D of the air discharge passage 14.

  In the fluid inflow control unit 20, the conductivity of the exhaust fluid (mixed fluid such as exhaust air and generated water) discharged from the fuel cell 10 to the air discharge passage 14 is measured by the conductivity meter 21, and the above-described embodiment. Similar to 1, it is determined whether or not the amount of impurities contained in the discharged fluid is the amount of impurities to be removed by the impurity remover 24. Then, the opening and closing of the on-off valves 23 and 25 may be controlled according to the determination result.

  In this way, even when the bypass passage 122 is formed in the oxidizing gas (air) discharge system and the impurity remover 24 is provided, all of the discharged fluid discharged from the fuel cell 10 is allowed to pass through the impurity remover 24. Instead, since only the discharge fluid that needs to pass through the impurity remover 24 is allowed to pass through the impurity remover 24, the amount of discharged fluid that passes through the impurity remover 24 can be reduced, so that the pressure loss is reduced. In addition, the lifetime of the impurity remover 24 can be improved.

  In the configuration shown in FIG. 11, the bypass passage 122 is formed on the downstream side of the humidifying module 8, and the impurity remover 24 is disposed in the bypass passage 122. The bypass passage 122 is an air outlet of the fuel cell 10. 13 and the humidification module 8 may be formed.

  Further, when the bypass passage 122 is formed in the oxidant gas (air) discharge system and the impurity remover 24 is provided, the branch point C and the junction point D of the air discharge passage 14 are also in accordance with the technique shown in FIG. More specifically, another impurity remover may be disposed between the junction point D of the on-off valve 25 shown in FIG. Further, in accordance with the technique shown in FIG. 7, a bypass passage is further formed to bypass the upstream of the on-off valve 25 to the downstream of the on-off valve 25, the on-off valve 23 is opened, the on-off valve 25 is closed, and the discharged fluid is bypassed. You may make it detour.

  Furthermore, it goes without saying that the bypass passage and the impurity remover may be disposed in both the hydrogen circulation system and the oxidizing gas discharge system.

  In the first embodiment, an ion exchanger is used as the impurity removers 24 and 34. However, the present invention is not limited to this, and the impurity remover according to the present invention removes impurities in the fluid. If possible, it is not necessary to have a configuration mainly composed of an ion exchange resin.

  In the first embodiment, the case where a cyclone gas-liquid separator is used as the gas-liquid separator 26 has been described. However, the present invention is not limited to this, and a gas-liquid separator that separates gas and liquid by another method is used. Of course, it may be.

(Embodiment 2)
Next, a fuel cell system according to Embodiment 2 of the present invention will be described with reference to the drawings.

  FIG. 12 is a schematic configuration diagram of a fuel cell system according to the second embodiment. In the second embodiment, the same members as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 12, the main difference of the fuel cell system 2 according to the second embodiment from the fuel cell system 1 according to the first embodiment is that a bypass passage 222 is branched from the hydrogen supply passage 17 as a branch passage. The impurity removing device 24 is disposed in the bypass passage 222.

  That is, a hydrogen discharge passage 19 connected to a hydrogen discharge port 18 of the fuel cell 10 is joined to the hydrogen supply passage 17 at a junction E, and the hydrogen supply passage 17 has a fuel downstream at the junction E. It serves as a circulation path for supplying unreacted hydrogen discharged from the battery 10 to the fuel cell 10 again. On the downstream side of the junction point E of the hydrogen supply passage 17, an on-off valve 123 composed of a three-way valve is provided. The on-off valve 123 serves as a branch point F, and a bypass passage 222 is branched therefrom. An impurity remover 24 is disposed in the bypass passage 222. The downstream side of the bypass passage 222 from the impurity remover 24 joins the hydrogen supply passage 17 at a junction G.

  A load measuring device (not shown) for measuring the load of the fuel cell 10 is connected to the fuel cell 10, and the opening and closing of the on-off valve 123 is controlled by each step shown in FIG. That is, first, the hydrogen circulation amount is calculated based on the graph shown in FIG. 8 from the value measured by the load measuring device. (Step S201). Next, when the hydrogen circulation amount obtained in step S201 is smaller than a preset threshold value (step S202: YES), the hydrogen supply passage 17 (the circulation passage through which the circulating hydrogen from the fuel cell 10 is also supplied). It is determined that it is not necessary to pass the hydrogen passing through the impurity remover 24, and the on-off valve 123 is adjusted so that the hydrogen supply passage 17 is opened and the bypass passage 222 is closed. (Step S203). By this operation, hydrogen (including circulating hydrogen) flowing through the hydrogen supply passage 17 does not flow into the bypass passage 222 and is thus supplied to the fuel cell 10 without passing through the impurity remover 24.

  On the other hand, when the hydrogen circulation amount obtained in step S201 exceeds a preset threshold value (step S202: NO), hydrogen (including circulating hydrogen) flowing through the hydrogen supply passage 17 is removed from the impurity remover 24. Therefore, it is determined that impurities should be removed, and the on-off valve 123 is adjusted so that the hydrogen supply passage 17 is closed and the bypass passage 222 is opened. (Step S204). By this operation, the hydrogen flowing through the hydrogen supply passage 17 flows to the bypass passage 222 side and is supplied to the fuel cell 10 after impurities are removed by the impurity remover 24.

  In the second embodiment, a fluid inflow control unit that controls the amount of hydrogen flowing into the bypass passage 222 is configured by a load measuring device (not shown) and the on-off valve 123.

  In this way, not all of the unreacted hydrogen (circulated hydrogen) discharged from the fuel cell 10 and the hydrogen supplied from the hydrogen supply source 16 are allowed to pass through the impurity remover 24 instead of passing through the impurity remover 24. By passing only the necessary hydrogen through the impurity remover 24, the amount of hydrogen passing through the impurity remover 24 can be reduced, so that pressure loss can be reduced and the lifetime of the impurity remover 24 can be reduced. Can also be improved.

  In the second embodiment, the case where the switching between the hydrogen supply passage 17 and the bypass passage 222 is performed using the on-off valve 123 formed of a three-way valve has been described. The on-off valve is disposed downstream of the junction point E of FIG. 17, the on-off valve is disposed on the upstream side of the impurity remover 24 in the bypass passage 222, and both the on-off valves are controlled to thereby control the hydrogen supply passage. 17 and the bypass passage 222 may be switched.

  Further, as shown in FIG. 14, the control of the on-off valve 123 is performed after the step S 201 described in the second embodiment is performed, and the opening degree of the on-off valve 123 is changed according to the calculated hydrogen circulation amount. You may set based on the graph shown in FIG. Further, as shown in FIG. 16, for example, switching between the hydrogen supply passage 17 and the bypass passage 222 may be performed by controlling opening and closing of the flap valve 124.

  Further, a bypass passage 122 as shown in FIG. 11 may be formed in the oxidizing gas (air) discharge system of the system shown in FIG.

1 is a schematic configuration diagram of a fuel cell system according to an embodiment of the present invention. It is a figure which shows the relationship between the electrical conductivity of the exhaust gas discharged | emitted from the fuel cell shown in FIG. 1, and the amount of impurities contained in the said exhaust gas. It is a flowchart which shows operation | movement of the fluid inflow amount control part shown in FIG. It is a schematic block diagram of the fuel cell system concerning other embodiment of this invention. It is a schematic block diagram of the fuel cell system concerning other embodiment of this invention. It is a schematic block diagram of the fuel cell system concerning other embodiment of this invention. It is a schematic block diagram of the fuel cell system concerning other embodiment of this invention. It is a figure which shows the relationship between the fuel cell load of the fuel cell system concerning other embodiment of this invention, and a circulating hydrogen flow rate. It is a figure which shows the relationship between the discharge fluid (circulation hydrogen flow rate) discharged | emitted by the hydrogen discharge passage of the fuel cell system concerning other embodiment of this invention, and pressure loss. It is a figure which shows the relationship between the fuel cell load of the fuel cell system concerning other embodiment of this invention, and the ion concentration of discharge fluid. It is a schematic block diagram of the fuel cell system concerning other embodiment of this invention. It is a schematic block diagram of the fuel cell system concerning Embodiment 2 of this invention. It is a flowchart which shows operation | movement of the fluid inflow amount control part of the fuel cell system concerning Embodiment 2 of this invention. It is a flowchart which shows operation | movement of the fluid inflow amount control part of the fuel cell system concerning other embodiment of this invention. It is a figure which shows the relationship between the circulating hydrogen flow rate and bypass ratio of the fuel cell system concerning other embodiment of this invention. It is the schematic which shows a part of fuel cell system concerning other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell system 10 Fuel cell 20 Fluid inflow control part 19 Hydrogen discharge passage 21, 30 Conductivity meter 22, 44, 122, 222 Bypass passage 23, 25, 123 On-off valve 24, 34 Impurity remover 26 Gas-liquid separator 31 Flow meter

Claims (11)

A fuel cell system in which an impurity remover for removing impurities mixed in the exhaust fluid is disposed in a discharge passage through which the exhaust fluid discharged from the fuel cell flows,
A branch passage branched from the discharge passage;
Fluid inflow control means for controlling the amount of exhaust fluid flowing into the branch passage and the discharge passage, disposed upstream of the branch passage;
With
A fuel cell system in which the impurity remover is disposed in the branch passage.   2. The fuel cell system according to claim 1, wherein the fluid inflow amount control means includes an on-off valve that allows the exhaust fluid to flow into at least one of the branch passage and the discharge passage.   3. The fuel cell according to claim 1, wherein the fluid inflow amount control means controls the amount of exhaust fluid flowing into the branch passage and the discharge passage according to a value determined by an operating state of the fuel cell. system.   The fuel cell system according to claim 3, wherein the value determined by the operating state of the fuel cell is a state quantity of the exhaust fluid.   The fuel cell system according to claim 4, wherein the state quantity of the exhaust fluid is at least one of conductivity, pressure, flow rate, pH, and ion concentration of the exhaust fluid.   The fuel system according to claim 3, wherein a value determined by an operating state of the fuel cell is based on an operating state of a pump that sucks the discharged fluid.   The fuel cell system according to claim 3, wherein a value determined by an operating state of the fuel cell is based on a power generation state of the fuel cell.   8. The impurity removing unit is disposed on the discharge passage downstream from the branch point of the branch passage and upstream from the junction of the branch passage. 8. Fuel cell system.   9. The fuel cell system according to claim 8, wherein a capacity of the impurity remover disposed in the discharge passage is smaller than a capacity of the impurity remover disposed in the branch passage.   10. The fuel cell system according to claim 9, wherein the fluid inflow amount control means controls the amount of exhaust fluid flowing into the branch passage and the discharge passage in accordance with the capacity of the impurity remover. A fuel cell system in which an impurity remover for removing impurities mixed in the fuel gas is disposed in a circulation passage through which the fuel gas discharged from the fuel cell flows.
A branch passage branched from the circulation passage;
A fluid inflow control means that is disposed upstream of the branch passage and controls the amount of fuel gas flowing into the branch passage and the circulation passage;
With
A fuel cell system in which the impurity remover is disposed in the branch passage.

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