JP2006012553A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system capable of improving fuel utilizing efficiency by preventing impurity from accumulating in one place in a fuel cell. <P>SOLUTION: The fuel cell system has the fuel cell, an exhaust passage exhausting waste gas from an anode of the fuel cell, and a valve arranged on the exhaust passage. A separator as a constituent of the fuel cell is divided into a plurality of blocks. A current obtaining means can take out current from respective separators divided into plurality. A current ratio control means controls so that the current ratio obtained from the plurality of current obtaining means changes when an opening/closing means is closed. In the above case, the most downstream position of hydrogen is positioned at a block capable of obtaining largest amount of current. Consequently, since the most downstream position of hydrogen is moved by changing the current ratio, the position of the impurity can be moved and the impurity can be diffused. By the above, since hydrogen purging period can be shortened, the utilizing efficiency of the fuel cell is improved. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell system, and more particularly to improvement in utilization efficiency of fuel gas.

  A fuel cell system mounted on a fuel cell vehicle or the like is known. The fuel cell system has a fuel cell stack (hereinafter simply referred to as “fuel cell”) composed of an anode electrode (that is, a hydrogen electrode or a fuel electrode) and a cathode electrode (that is, an oxygen electrode) as a main body. The system is equipped with a tank for storing fuel gas such as hydrogen to be supplied, a pump for returning exhaust gas containing unused fuel gas to the original anode electrode, and the like. In a fuel cell, hydrogen and oxygen contained in air react to generate electric power.

  Here, in the fuel cell system, as the cell reaction proceeds, nitrogen in the oxidizing gas and moisture for humidification ooze out from the cathode electrode to the anode electrode side through the electrolyte membrane. For this reason, the partial pressure of nitrogen or water vapor (hereinafter, collectively referred to as “impurities”) increases, and the power generation capacity of the fuel cell decreases.

  Therefore, in general, a valve provided in the discharge path of the anode electrode is opened to discharge the gas containing impurities. For example, in Patent Document 1, when it is determined that the power generation capacity of a fuel cell has decreased, an open / close valve disposed in the discharge path on the anode electrode side is opened (ie, “hydrogen purge”), and unused gas And a technique of supplying a gas containing impurities to a sub fuel cell provided on the downstream side. Further, in Patent Document 2, when it is determined that the output voltage of the fuel cell is lowered, an impurity present in the fuel gas supply path is released to the outside by opening a shut-off valve provided at the discharge port. The technology is described. Patent Document 3 describes a technique in which fuel is supplied from a plurality of supply ports in a fuel cell system having a plurality of supply ports and discharge ports in order to diffuse fuel gas within the surface. In addition, Patent Document 4 describes a technique in which divided current collector plates are arranged with a small interval in order to improve a decrease or variation in current collection efficiency accompanying an increase in capacity of a fuel cell.

  However, in the fuel cell system described above, impurities accumulate in one place in the fuel cell, and the power generation efficiency of the entire fuel cell may be reduced. Further, in order to prevent such a decrease in power generation efficiency, the hydrogen purge amount may increase.

JP 2003-77506 A JP 9-31167 A JP-A-11-144453 JP 61-284064 A

  The present invention has been made in order to solve such problems. The object of the present invention is to prevent the accumulation of impurities in one place in the fuel cell and improve the efficiency of fuel use. It is to provide a possible fuel cell system.

  In one aspect of the present invention, a fuel cell system includes a fuel cell in which an anode electrode and a cathode electrode are disposed, a gas supply path that supplies fuel gas to the anode electrode through a gas supply port of the anode electrode, Through the gas discharge port of the anode electrode, a gas discharge path for discharging the gas in the anode electrode, opening / closing means for opening and closing the gas discharge path, and a plurality of currents from a plurality of blocks of the anode electrode separator Current acquisition means; and current ratio control means for controlling the current acquisition means so that current ratios acquired from the plurality of current acquisition means change when the opening / closing means is closed.

  The fuel cell system is mounted on a fuel cell vehicle or the like. A fuel cell (fuel cell stack) includes an anode electrode and a cathode electrode, and generates electric power using fuel gas (such as hydrogen) supplied to the anode electrode and air (that is, oxygen) supplied to the cathode electrode. The fuel cell is provided with a discharge path for discharging unused hydrogen or gas containing impurities such as nitrogen and water vapor through the discharge port of the anode electrode. In this discharge path, for example, an opening / closing means such as a valve is provided. The current acquisition means can acquire current from a plurality of blocks of anode separators. The current ratio control means controls the current ratio acquired from the plurality of current acquisition means to change when the opening / closing means is closed.

  In the fuel cell, the most downstream position of hydrogen as the fuel gas (where the hydrogen flow rate or hydrogen flow rate is substantially “0”) is located in the block where the most current is acquired. Impurities are likely to accumulate at the most downstream position of the fuel gas. Therefore, by changing the current ratio acquired from a plurality of blocks, the most downstream position of the fuel gas can be moved so that impurities are not accumulated in one place in the anode electrode. Therefore, it is possible to reduce the number of times the impurities are discharged by opening the opening / closing means, and the utilization efficiency of the fuel cell is improved.

  Further, by changing the most downstream position of the fuel gas, not only the diffusion of impurities but also the diffusion of condensed water is performed. Thereby, the flooding in an anode pole can be prevented. Furthermore, the condensed water can be effectively used as humidified water in the fuel cell stack. Thereby, dry-out of the fuel cell stack can also be prevented.

  In one aspect of the fuel cell system, the current ratio control unit controls the current acquisition unit so that a magnitude relationship of currents acquired from the plurality of current acquisition units changes.

  In this aspect, the current ratio control means of the fuel cell system performs control so that the magnitude relationship between the currents acquired from the plurality of blocks also changes. For example, the current ratio acquired from the first block and the second block is changed from, for example, 7: 3 to 3: 7, and the current acquired from the second block is larger than that of the first block. So that the current ratio is controlled. As a result, the most downstream position of the fuel gas can be reliably moved to a different block, and impurities can be reliably moved and diffused.

  In another aspect of the fuel cell system, the anode electrode separator is divided into the plurality of blocks. In this aspect, since the anode separator is divided into blocks, no current flows between the plurality of blocks. Therefore, the current ratio control means can acquire current from each block according to the control amount, and can control the current ratio more accurately.

  In another aspect of the fuel cell system, the gas supply path is disposed at a position upstream of the first supply path for supplying fuel gas to the anode electrode and the opening / closing means on the gas discharge path. And a second supply path for supplying fuel gas to the anode electrode in a direction opposite to that of the first supply path.

  In this aspect, fuel gas can be supplied to the anode electrode from the first and second supply paths. As described above, by controlling the current ratio obtained from each block, the most downstream position of the fuel gas can be moved. However, when the fuel gas can be supplied only in one direction in the anode electrode, If impurities accumulate in the most downstream block in the direction, it cannot be moved, and power generation using that block cannot be performed. On the other hand, if the fuel gas can be supplied bidirectionally into the anode electrode, the impurities can be moved by reversing the fuel gas supply direction even in the above case. That is, by making it possible to supply fuel gas bidirectionally into the anode electrode, impurities can always be moved over the entire range of the plurality of blocks in the anode electrode, thereby reducing power generation efficiency and wasting fuel gas. Can be suppressed. In addition, since the power generation distribution in the plane of the anode can be made more uniform, the durability of the fuel cell stack can also be improved.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

[Configuration of fuel cell system]
FIG. 1 shows a schematic configuration diagram of a fuel cell system 50 according to one embodiment of the present invention. The fuel cell system 50 mainly includes a fuel cell (fuel cell stack) 1, a fuel tank 2, an ECU (Electronic Control Unit) 10, supply paths 3a, 3b, 3c, discharge paths 4a, 4b, and supply. Ports 5a, 5b, and 5c, a discharge port 6a, and a valve 8 are provided. The fuel cell system 50 is mounted on a fuel cell vehicle (hereinafter simply referred to as “vehicle”).

  The fuel cell 1 is a battery cell in which electrodes having a structure such as a porous layer capable of diffusing gas are formed on both surfaces of an electrolyte membrane 1c, with a conductive separator interposed between the layers, and the number of layers is increased. A corresponding output voltage can be taken out. In the drawing, for convenience of explanation, only a single cell structure in which a cathode electrode (air electrode) 1a and an anode electrode (fuel electrode) 1b are formed on the surface of the electrolyte membrane 1c is shown.

  The fuel cell 1 is a power supply for a motor for driving the vehicle, and generates a high DC voltage of about 300V. The generated voltage of the fuel cell 1 is output to an electric load such as an inverter (not shown) that supplies a current corresponding to a command torque or the like to the motor. The power generation voltage of the fuel cell 1 passes through the power cable 15 and is supplied to an inverter that supplies a current corresponding to a command torque to the motor, various auxiliary devices mounted on the vehicle, Output to the secondary battery.

  In the present embodiment, the separator of the fuel cell 1 is divided into a plurality of blocks. The fuel cell system 50 is configured to selectively acquire a current from at least one block among the plurality of blocks, or to acquire a different current in each block. Specifically, the switch unit 7 is provided in the middle of the power cable 15, and the fuel cell system 50 controls the switch unit 7 to change the current ratio acquired from each block. The switch unit 7 is controlled by a control signal S11 supplied from the ECU 10 in the fuel cell system 50. Details of the control of the switch unit 7 will be described later.

  Fuel gas (hereinafter simply referred to as “hydrogen”) is supplied to the fuel cell 1 from two locations of the supply ports 5b and 5c. As indicated by an arrow A2, the hydrogen supplied from the fuel tank 2 is divided into hydrogen passing through the supply path 3b and hydrogen passing through the supply path 3c. Then, hydrogen is supplied from the supply ports 5b and 5c to the anode 1b. The supply path 3b functions as a first supply path, and the supply path 3c functions as a second supply path.

  A discharge path 4b is connected in the middle of the supply path 3c. Further, a valve 8 is provided on the discharge path 4b. The valve 8 is controlled by a control signal S12 supplied from the ECU 10. Thereby, opening and closing of the valve 8 or adjustment of the opening amount is performed. Gas that passes through the discharge passage 4b by opening and closing the valve 8 or adjusting the opening amount (that is, a gas containing unused hydrogen, the above-described impurities, and the like is also simply referred to as “exhaust” hereinafter). The flow rate is controlled. When the valve 8 is closed, the exhaust does not pass through the discharge path 4b. On the other hand, when the valve 8 is open, the exhaust discharged from the anode 1b passes through the discharge path 4b as shown by the arrow A4. As described above, the valve 8 functions as an opening / closing means for opening / closing the discharge passage 4b.

  The air passes through the supply path 3a as indicated by the arrow A1, and is supplied to the cathode 1a from the supply port 5a. And the air discharged | emitted from the cathode 1a passes the discharge path 4a as shown by arrow A3 from the discharge port 6a.

  The ECU 10 includes a CPU, a ROM, a RAM, an A / D converter, an input / output interface, and the like (not shown). In the present embodiment, the ECU 10 supplies the control signal S11 to the switch unit 7 and supplies the control signal S12 to the valve 8. The ECU 10 controls the switch unit 7 and the valve 8 in accordance with the state of the fuel cell 1 and the state of the vehicle.

  The outline | summary is demonstrated about the control which ECU10 which concerns on this embodiment performs. ECU10 controls switch part 7 so that the current ratio of the current acquired from each block may change in the separator divided into a plurality of blocks. Normally, impurities are likely to accumulate at the most downstream position of hydrogen (where the hydrogen flow rate or hydrogen flow rate is substantially “0”), but in this embodiment, the most current is acquired at the most downstream position of hydrogen. Located in block. Therefore, the most downstream position can be moved by changing the current ratio. Therefore, the ECU 10 moves the most downstream position of hydrogen in the fuel cell 1 by changing the current ratio acquired from the plurality of blocks of the separator so that impurities are not accumulated in one place in the anode 1b. be able to. As a result, the number of times the impurities are discharged by opening the valve 8 can be reduced, so that the utilization efficiency of the fuel cell 1 is improved. Note that the ECU 10 controls the switch unit 7 when the valve 8 is closed. This is because the valve 8 is opened when the gas in the anode 1b is discharged, and in this case, it is not necessary to control the switch 7 to move the impurities. As described above, the ECU 10 functions as a current ratio control unit.

  Next, a specific structure of the fuel cell 1 according to this embodiment will be described.

  FIG. 2 is a schematic view showing the structure of the fuel cell 1. FIG. 2A is a side view showing the overall structure of the fuel cell 1. The fuel cell 1 is configured by stacking a plurality of single cells 1d. The stacked unit cells 1d are arranged on the end plate 1f. In the present embodiment, the separator of the fuel cell 1 is divided into a plurality of blocks. Specifically, the fuel cell 1 includes a plurality of current collecting plates 11a to 11d. In FIG. 2A, it is assumed that hydrogen is supplied from both the left and right directions of the page. That is, gas flows in the left-right direction of the paper surface in the fuel cell 1.

  FIG. 2B shows a plan view seen from the direction of arrow B in FIG. The fuel cell 1 includes current collecting plates 11a to 11d. A plurality of current collecting plates 11a to 11d are arranged in the gas flow direction. The switch unit 7 includes switches 7a, 7b, 7c, and 7d. The switch unit 7 having a plurality of switches 7a to 7d is constituted by, for example, a semiconductor switch. The switches 7a, 7b, 7c, and 7d are connected to current collector plates 11a, 11b, 11c, and 11d, respectively. Further, the switch unit 7 is controlled by the control signal S11 from the ECU 10 as described above. In addition, in FIG. 2, although the fuel cell 1 has shown what is equipped with the four current collecting plates 11a-11d, application of this invention is not limited to this number. Further, the shape and arrangement of the current collector plate are not limited to those illustrated. Further, in this example, the individual current collector plates are connected with separate switches, but the application of the present invention is not limited to this. For example, one switch may be connected to four current collector plates, or one switch may be connected to two current collector plates.

  FIG. 3 shows a specific example of the flow of hydrogen when opening and closing of the switches 7a to 7d is controlled. FIG. 3A shows the gas flow when only the switch 7a is closed and the other switches are opened. Since only the switch 7a is closed, a current flows only through the current collector plate 11a. Therefore, a current is acquired only from the current collector plate 11a. In this case, since hydrogen is consumed most at the position where the current collector plate 11a exists, the hydrogen downstream position indicated by reference numeral C1 is the position of the current collector plate 11a.

  FIG. 3B shows the flow of hydrogen when only the switch 7d is closed and the other switches are opened. Since only the switch 7d is closed, a current flows only through the current collector plate 11d. Therefore, a current is acquired only from the current collector plate 11d. That is, since hydrogen is consumed most at the position where the current collector plate 11d exists, the most downstream position of hydrogen indicated by reference C2 is the position of the current collector plate 11d.

  FIG. 4 shows the fluctuation of impurities when the opening / closing of the switches 7a to 7d is controlled. The fuel cell 1 shown in FIG. 4 is shown as a cross-sectional view along the cutting line X-X ′ shown in FIG. 2.

  FIG. 4A shows a case where only the switch 7a is closed and the other switches are opened (that is, this corresponds to the example shown in FIG. 3A). Since only the switch 7a is closed, a current flows only through the current collector plate 11a. Therefore, the most downstream position of hydrogen comes to the position where the current collector plate 11a exists. Since the hydrogen flow velocity is substantially “0” at the most downstream position of hydrogen, impurities accumulate at this position. Therefore, the impurity D1 accumulates at the position where the current collector plate 11a exists.

  FIG. 4B shows a case where only the switch 7d is closed and the other switches are opened (that is, this corresponds to the example shown in FIG. 3D). Since only the switch 7d is closed, a current flows only through the current collector plate 11d. Therefore, the most downstream position of hydrogen comes to the position where the current collector plate 11d exists. Therefore, the impurity D2 accumulates at the position where the current collector plate 11d is present.

  As described above, the impurities can be moved in the fuel cell 1 by switching the switches 7a to 7d. FIG. 4C shows the position of impurities when such switching of the switch is repeated. Since the impurity moves each time the switch is switched, the impurity is not fixed in one place. Therefore, when the switch is repeatedly switched, the impurity D3 is diffused over substantially the entire fuel cell 1.

  When impurities are diffused in this way, the impurity concentration per unit volume is lowered. Therefore, it is difficult to reach a state where the output performance of the entire fuel cell 1 is significantly deteriorated. Thereby, in order to discharge | emit the impurity in the anode 1b, the frequency | count of discharging | emitting the gas in the anode 1b can be reduced. That is, the hydrogen purge amount or purge time can be reduced. Furthermore, since the power generation distribution in the surface of the anode 1b can be made more uniform, the durability of the fuel cell 1 can also be improved.

  Further, by controlling the switches 7a to 7d as described above, not only the diffusion of impurities but also the diffusion of condensed water in the fuel cell 1 can be performed. Thereby, flooding in the anode 1b can be prevented. Furthermore, the condensed water can be effectively used as humidified water in the fuel cell 1. Thereby, the dry-out of the fuel cell 1 can also be prevented.

  Here, the switch control method by the ECU 10 will be specifically described.

  FIG. 5 shows an example of a control signal supplied from the ECU 10 to the switches 7a to 7d. The ECU 10 supplies the control signal S11a to the switch 7a, supplies the control signal S11b to the switch 7b, supplies the control signal S11c to the switch 7c, and supplies the control signal S11d to the switch 7d. In this example, the ECU 10 is controlled so as to be closed in the order of the switch 7a → the switch 7b → the switch 7c → the switch 7d (in this case, only one switch is closed, and the other The switch is open). Therefore, the current collecting plate from which current is acquired changes in the order of current collecting plate 11a → current collecting plate 11b → current collecting plate 11c → current collecting plate 11d. As a result, the position of the current collecting plate where impurities accumulate is also moved from the current collecting plate 11a → the current collecting plate 11b → the current collecting plate 11c → the current collecting plate 11d. After opening the switch 1d, the ECU 10 closes the switch 1a again and repeats the same control. As a result, impurities are diffused throughout the fuel cell 1 without accumulating in one place.

  Note that, as in the example shown in FIG. 5, it is not always necessary to make the switching frequency of the four switches common. Further, it is not necessary to periodically open and close the switch. Similarly, the time during which a switch is closed or the time span during which it is open need not be common among the switches. That is, the control method of the switches 7a to 7d is not limited to closing only one switch, and currents may be taken out from a plurality of current collector plates at different current ratios by simultaneously closing a plurality of switches.

  In this case, the control of the acquired current from each current collector plate by the ECU 10 is sufficient if the current ratio acquired from each current collector plate is changed, and the magnitude relationship between the currents acquired from each current collector plate may not be changed. . For example, assuming that the separator is divided into two blocks for simplicity of explanation, the current ratio obtained from the first current collector plate and the second current collector plate is changed from 10: 0 to 0:10. Then, the impurities move from the position of the first current collector plate to the position of the second current collector plate. On the other hand, when the current ratio obtained from the first current collector plate and the second current collector plate is changed from 9: 1 to 6: 4, since the magnitude relationship of the current does not change, the impurities are still the first. Although the ratio is larger in the current collector plate, the ratio changes, so that the impurities located in the first current collector plate move to the second current collector plate to some extent. The effect of diffusing impurities can be obtained even within a narrow range in the electric plate. That is, in the present invention, the diffusion effect of impurities can be obtained by changing the current ratio obtained from a plurality of current collector plates, and it is essential to change the magnitude relationship between the currents obtained from the plurality of current collector plates. is not. However, if the current ratio is changed so that the magnitude relationship between the currents to be acquired is changed, the impurity diffusion effect is naturally increased.

  Further, the impurities are moved more finely by controlling in detail the time when the 7a-7d in the four switches are open or closed, the number of the switches that are closed, or the timing for opening and closing the switches. Can do. In other words, pulsation can be generated in the hydrogen flow in the anode 1b.

[Modification]
Next, a fuel cell system according to a modification of the present invention will be described.

  FIG. 6 shows a schematic configuration diagram of a fuel cell system 51 according to a modification. In the fuel cell system 50 shown in FIG. 1, hydrogen is supplied to the anode 1b from two supply ports. However, in the fuel cell system 51 according to the modification, hydrogen is supplied from one supply port. Since other components are the same as those of the fuel cell system 50 described above, description thereof is omitted.

  In the fuel cell system 51, hydrogen is supplied to the anode 1b only from the supply port 5b. Therefore, a gas flow in only one direction occurs in the anode 1b. The anode 1b is provided with a discharge port 6b, and a discharge path 4b is connected to the discharge port 6b. Further, a valve 8 is provided in the middle of the discharge path 4b. When the valve 8 is opened, gas is discharged from the anode 1b.

  Even when the fuel cell 1 is configured as described above, the ECU 10 can control the switch unit 7 to move the most downstream position of hydrogen in the anode 1b. Thereby, it is possible to prevent the impurities from being fixed at one place.

  Specifically, the movement of impurities in the fuel cell 1 will be described with reference to FIG. FIG. 7 shows a current collector plate similar to that shown in FIG. 2B, and shows the gas flow when the opening and closing of the switch is controlled. 7 (a) shows a case where only the switch 7a is closed, FIG. 7 (b) shows a case where only the switch 7b is closed, FIG. 7 (c) shows a case where only the switch 7c is closed, and FIG. (D) shows the one in which only the switch 7d is closed. In this case, the ECU 10 switches in order from the switch 7a → the switch 7b → the switch 7c → the switch 7d. That is, the current collecting plate from which the current is acquired changes from the current collecting plate 11a → the current collecting plate 11b → the current collecting plate 11c → the current collecting plate 11d. Therefore, the most downstream position of hydrogen moves from E1 → E2 → E3 → E4. Therefore, finally, impurities accumulate at a position where the current collector plate 11d is located. Since the flow of gas in the fuel cell 1 is unidirectional (flows from the current collecting plate 11a side to the current collecting plate 11d side), the impurities accumulated in the position where the current collecting plate 1d is located are changed to any switch thereafter. Also don't move. Therefore, after that, it is preferable to switch from the switch 7a → the switch 7b → the switch 7c → the switch 7a → the switch 7b → the switch 7a and open the valve 8 when the switching of these switches is completed. Thereby, the power generation of the fuel cell 1 is not harmed by the accumulated impurities. And wasteful discharge of hydrogen can be suppressed as much as possible, and impurities can be discharged effectively.

  Next, a modified example relating to current ratio control performed by the ECU 10 using the switch unit 7 will be described. In the above, the current ratio is controlled so as to change by acquiring current from at least one current collector plate by opening and closing the switch, but instead, it may be controlled so that the current ratio changes using a variable resistor. .

  FIG. 8 shows a specific example of the fuel cell 1 to which a variable resistor is connected. The fuel cell 1 includes current collecting plates 11a, 11b, 11c, and 11d. The variable resistor includes a variable resistor 9a, a variable resistor 9b, a variable resistor 9c, and a variable resistor 9d (hereinafter, when subscripts are omitted and shown as “variable resistor 9”, all of the variable resistors 9a to 9d are included. Means something included). The variable resistors 9a, 9b, 9c, 9d are connected to current collector plates 11a, 11b, 11c, 11d, respectively. These variable resistors 9a, 9b, 9c, 9d are controlled by control signals S13a, 13b, 13c, 13d from the ECU 10, respectively. The control signal S13a to S13d allows the ECU 10 to change the resistance value of the variable resistor.

  As described above, the current ratio acquired from the plurality of current collector plates can be controlled by changing the resistance value of the variable resistor. By changing the resistance value in detail using a variable resistor, the current acquired from each current collector plate can be finely controlled. Thereby, the most downstream position of hydrogen can be moved finely. Further, the current can be acquired from a wide range within the surface of the fuel cell 1 even during the control of the current ratio. For example, even if current is acquired from all of the current collector plates 11a, 11b, 11c, and 11d, the current value acquired from each of them can be made different. Thereby, since it is not necessary to acquire an electric current only from a small number (for example, one) current collecting plate, durability of the fuel cell 1 can be improved. In addition, since the variable resistor is used, the magnitude relation of the current ratio acquired from the plurality of current collector plates can be easily changed.

  Note that the configuration of the variable resistor is not limited to that described above. In the above example, each variable current collector is connected to a separate variable resistor. However, for example, one variable resistor may be connected to four current collectors, or two current collectors may be connected. One variable resistor may be connected to the plate.

  FIG. 9 shows a modification regarding the configuration of the current collector plate in the fuel cell 1. The current collector plate shown in FIG. 9 is configured by dividing the current collector plate in the direction perpendicular to the gas flow (the vertical direction in FIG. 9). That is, four current collecting plates are arranged in the gas flow direction, and these four sets are provided in two stages in the direction perpendicular to the gas flow. Further, in the above example shown in FIG. 2 and the like, a configuration in which a plurality of current collector plates are completely separated is shown, but a configuration in which a plurality of current collector plates are connected as in this example is also possible. Good. In other words, adjacent current collector plates are connected by a portion indicated by a region F in FIG. In this case, it is preferable that the resistance value of the connection portion F is increased. For example, the width of the connection portion F is narrowed, or the connection portion F is made of a material having a high electrical resistivity. As a result, it becomes difficult for current to flow between adjacent current collecting plates, and a current ratio appropriately corresponding to the control signal from the ECU 10 can be acquired.

1 is a block diagram showing a schematic configuration of a fuel cell system according to an embodiment of the present invention. It is the schematic shown about the whole structure and current collector of a fuel cell. It is a figure which shows the specific example of the flow of gas when opening / closing of a switch is controlled. It is a figure which shows the movement of an impurity when opening / closing of a switch is controlled. It is a figure which shows the specific example of the control signal which ECU supplies with respect to a switch. It is a block diagram which shows schematic structure of the fuel cell system which concerns on the modification of this invention. It is a figure which shows the gas flow when opening / closing of a switch is controlled in the fuel cell system which concerns on a modification. It is a figure which shows the structure of the current ratio control means which concerns on the modification of this invention. It is a figure which shows the structure of the current collecting plate of the fuel cell which concerns on the modification of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell 1a Cathode electrode 1b Anode electrode 2 Fuel tank 3a, 3b, 3c Supply path 4a, 4b Discharge path 5a, 5b, 5c Supply port 6a, 6b Discharge port 7 Switch part 8 Valve 10 ECU (Electronic Control Unit)
11a, 11b, 11c, 11d Current collecting plate 50, 51 Fuel cell system

Claims (4)

A fuel cell in which an anode and a cathode are disposed;
A gas supply path for supplying fuel gas to the anode electrode through a gas supply port of the anode electrode;
A gas discharge path for discharging the gas in the anode electrode through the gas discharge port of the anode electrode;
Opening and closing means for opening and closing the gas discharge path;
A plurality of current acquisition means for acquiring current from a plurality of blocks of the anode separator;
A fuel cell system comprising: current ratio control means for controlling the current acquisition means so that current ratios acquired from the plurality of current acquisition means change when the opening / closing means is closed. 2. The fuel cell system according to claim 1, wherein the current ratio control unit controls the current acquisition unit so that a magnitude relationship between currents acquired from the plurality of current acquisition units changes. The fuel cell system according to claim 1, wherein the anode electrode separator is divided into the plurality of blocks. The gas supply path is
A first supply path for supplying fuel gas to the anode electrode;
A second supply path that is disposed at a position upstream of the opening / closing means on the gas discharge path and that supplies fuel gas to the anode electrode in a direction opposite to the first supply path. The fuel cell system according to claim 1 or 2.

Images