JP2010027217A - Fuel cell system - Google Patents

Abstract

A fuel cell is started at a low temperature by warming up the fuel cell without complicating the system.
A fuel cell system generates heat by storing a part of hydrogen supplied to a fuel cell, a hydrogen storage means for storing hydrogen, and a hydrogen storage means for storing hydrogen by electrochemical reaction between hydrogen and oxygen. A hydrogen storage alloy capable of exchanging heat with the fuel cell, a measuring means for measuring the temperature of the fuel cell, a control means for starting the supply of hydrogen from the hydrogen storage means to the fuel cell according to the temperature of the fuel cell, The control means controls the supply pressure of hydrogen from the hydrogen storage means to the fuel cell in accordance with the temperature of the fuel cell after the supply of hydrogen to the fuel cell is started.
[Selection] Figure 3

Description

  The present invention relates to a fuel cell and a fuel cell system that generate water during power generation.

In recent years, a fuel cell has attracted attention as a power source excellent in operating efficiency and environmental performance. For example, a solid polymer electrolyte membrane type fuel cell generates electric power by an electrochemical reaction by supplying hydrogen as a fuel gas to an anode electrode and supplying oxygen or air as an oxidant gas to a cathode electrode. Fuel cells are used in various environmental situations, and in a sub-freezing atmosphere, the temperature of the fuel cell body is increased in order to suppress freezing of the fuel cell body and the gas supply flow path. There is a technique in which a hydrogen storage alloy tank is installed between a high-pressure hydrogen tank and a fuel cell, and heat exchange between the hydrogen storage alloy tank and the fuel cell is performed via a coolant (for example, see Patent Document 3).
JP 2004-30979 A JP 2004-53208 A JP 2005-174724 A

  In the conventional technology, since the hydrogen storage alloy tank is installed in the vehicle body, the vehicle body weight increases and the cost also increases. Further, when heat exchange between the hydrogen storage alloy tank and the fuel cell is performed via the coolant, the system becomes complicated. The present invention has been made in view of the above problems, and an object of the present invention is to start a fuel cell at a low temperature by warming up the fuel cell without complicating the system.

  The present invention employs the following means in order to solve the above-described problems. That is, the present invention relates to a fuel cell that generates electricity by an electrochemical reaction between hydrogen and oxygen, a hydrogen storage means that stores hydrogen, and a portion of the hydrogen supplied to the fuel cell that absorbs heat to generate heat. A hydrogen storage alloy capable of exchanging heat with the battery, first measurement means for measuring the temperature of the fuel cell, and control means for starting supply of hydrogen from the hydrogen storage means to the fuel cell in accordance with the temperature of the fuel cell; The control means is a fuel cell system that controls the supply pressure of hydrogen from the hydrogen storage means to the fuel cell in accordance with the temperature of the fuel cell after the supply of hydrogen to the fuel cell is started.

  According to the fuel cell system, the hydrogen storage alloy generates heat by storing part of the hydrogen supplied to the fuel cell. Therefore, when the supply of hydrogen to the fuel cell is started, the temperature of the fuel cell is raised by heat exchange between the hydrogen storage alloy and the fuel cell. The hydrogen storage alloy tends to increase the calorific value when the applied pressure of hydrogen is increased. Since the hydrogen storage alloy stores part of the hydrogen supplied to the fuel cell, if the supply pressure of hydrogen to the fuel cell is increased, the applied pressure of hydrogen to the hydrogen storage alloy also increases. Therefore, the amount of heat generated by the hydrogen storage alloy can be controlled by controlling the supply pressure of hydrogen to the fuel cell. And it becomes possible to raise a fuel cell to desired temperature by controlling the supply pressure of hydrogen to a fuel cell.

The fuel cell system further includes air supply means for supplying air containing oxygen to the fuel cell, and the control means controls the air so that the hydrogen pressure in the fuel cell and the air pressure are the same. You may make it control the supply pressure of the air from a supply means to a fuel cell. According to the fuel cell system, by controlling the air supply pressure from the air supply means to the fuel cell, the hydrogen pressure and the air pressure in the fuel cell can be made the same pressure. As a result, it is possible to suppress damage to the electrolyte membrane in the fuel cell due to an imbalance between the hydrogen pressure in the fuel cell and the air pressure.

  In addition, the fuel cell system may further include a stop unit that stops the delivery of hydrogen delivered from the fuel cell, and the hydrogen storage alloy may be provided in the fuel cell. According to the fuel cell system, the hydrogen pressure in the fuel cell can be increased by stopping the delivery of the hydrogen sent from the fuel cell. By providing the hydrogen storage alloy in the fuel cell, it becomes possible to increase the pressure applied to the hydrogen storage alloy more quickly. Thereby, the calorific value of the hydrogen storage alloy can be increased without increasing the supply pressure of hydrogen to the fuel cell.

  The fuel cell system further includes air supply means for supplying air containing oxygen to the fuel cell, and the control means supplies air supply pressure from the air supply means to the fuel cell, from the hydrogen storage means to the fuel cell. The pressure may be controlled to be the same as the hydrogen supply pressure. According to the fuel cell system described above, the pressure of hydrogen in the fuel cell is controlled by controlling the supply pressure of air from the air supply means to the fuel cell to be the same as the supply pressure of hydrogen from the hydrogen storage means to the fuel cell. And the air pressure can be the same. As a result, it is possible to suppress breakage of the electrolyte membrane in the fuel cell due to imbalance between the hydrogen pressure in the fuel cell and the air pressure.

  The fuel cell system may further include a second measurement unit that measures the outside air temperature, and the control unit may start supplying hydrogen from the hydrogen storage unit to the fuel cell according to the outside air temperature. . According to the fuel cell system, it is possible to start supplying hydrogen from the hydrogen storage means to the fuel cell with reference to the outside air temperature.

  According to the present invention, it is possible to start the fuel cell at a low temperature by warming up the fuel cell without complicating the system.

  Hereinafter, a fuel cell system according to the best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described with reference to the drawings. The configuration of the following embodiment is an exemplification, and the present invention is not limited to the configuration of the embodiment.

  A fuel cell system according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing a fuel cell 2 included in a fuel cell stack 1 provided in the fuel cell system according to the present embodiment. FIG. 2 is a top view of the fuel cell 2 included in the fuel cell stack 1 included in the fuel cell system according to the present embodiment.

  The fuel cell stack 1 is configured by stacking a plurality of fuel cells 2. The fuel cell 2 includes separators 3 and 4, a membrane electrode assembly (MEA) 5, and a hydrogen storage alloy 6. The membrane electrode assembly 5 is provided between the separator 3 and the separator 4. The hydrogen storage alloy 6 is provided between the membrane electrode assembly 5 and the separator 4.

  The membrane electrode assembly 5 includes an electrolyte membrane 7, catalyst layers 8 and 9, and gas diffusion layers 10 and 11. In FIG. 1, the catalyst layer 8 is provided on the front side of the electrolyte membrane 7, and the catalyst layer 9 is provided on the back side of the electrolyte membrane 7. Since the catalyst layer 9 is provided on the back side of the electrolyte membrane 7, it is not shown in FIG.

The electrolyte membrane 7 is, for example, a solid polymer membrane. The catalyst layers 8 and 9 are respectively provided on both sides of the electrolyte membrane 7 so as to be in contact with the electrolyte membrane 7. The catalyst layer 8 functions as a cathode (oxygen electrode). The catalyst layer 9 functions as an anode (hydrogen electrode).

  The gas diffusion layer 10 is provided between the membrane electrode assembly 5 and the separator 3 so as to be in contact with the catalyst layer 8. A cathode-side internal flow path 12 is formed in the separator 3. Since the separator 3 and the gas diffusion layer 10 are arranged close to each other, a part of the inner wall surface of the cathode-side internal channel 12 is constituted by the separator 3, and the other inner wall surface of the cathode-side inner channel 12 is provided. The part is constituted by the gas diffusion layer 10. Air (also referred to as cathode gas) supplied to the fuel cell stack 1 flows through the cathode-side internal flow path 12 in the direction indicated by the arrow A in FIG.

  The gas diffusion layer 11 is provided between the membrane electrode assembly 5 separator 4 so as to be in contact with the catalyst layer 9. An anode side internal flow path 13 is formed in the separator 4. By arranging the separator 4 and the hydrogen storage alloy 6 close to each other, a part of the inner wall surface of the anode-side internal channel 13 is constituted by the separator 4, and the other inner wall surface of the anode-side inner channel 13 is arranged. The part is constituted by the hydrogen storage alloy 6. The hydrogen supplied to the fuel cell stack 1 flows through the anode-side internal flow path 13 in the direction indicated by the arrow B in FIG.

  Hydrogen flowing through the anode-side internal flow path 13 is supplied to the catalyst layer 9 through the hydrogen storage alloy 6 and the gas diffusion layer 11. In the catalyst layer 9, hydrogen ions are generated from hydrogen. Air that flows through the cathode-side internal flow path 12 is supplied to the catalyst layer 8 via the gas diffusion layer 10. In the fuel cell 2, an electrochemical reaction between hydrogen and oxygen occurs, and electric energy is generated. In the catalyst layer 8, water is generated by combining hydrogen ions generated from hydrogen and oxygen.

  The hydrogen storage alloy 6 is provided in contact with the separator 4. For example, the hydrogen storage alloy 6 may be attached to the separator 4. Moreover, you may make it equip the hydrogen storage alloy 6 so that only the location in which the anode side internal flow path 13 is formed among the separators 4 may be covered.

  The hydrogen storage alloy 6 stores hydrogen by pressurization or cooling, and releases hydrogen by depressurization or heating. Further, the hydrogen storage alloy 6 generates heat when storing hydrogen and absorbs heat when releasing hydrogen. The amount of heat generated by the hydrogen storage alloy 6 increases as the pressure of supplied hydrogen (pressure of applied hydrogen) increases.

  In this embodiment, the hydrogen storage alloy 6 is provided between the membrane electrode assembly 5 and the separator 4. However, instead of this, the material of the gas diffusion layer 11 may be the hydrogen storage alloy 6. That is, the fuel cell 2 may be configured so that the hydrogen storage alloy 6 functions as the gas diffusion layer 11. By configuring the fuel cell 2 so that the hydrogen storage alloy 6 functions as the gas diffusion layer 11, the fuel cell 2 can be reduced in size. By reducing the size of the fuel cell 2, the size of the fuel cell stack 1 can be reduced. Alternatively, the hydrogen storage alloy 6 and the catalyst layer 9 may be integrated by dissolving the hydrogen storage alloy 6 in the catalyst layer 9.

  When the hydrogen storage alloy 6 is in a state of storing hydrogen, the hydrogen storage alloy 6 stores hydrogen flowing through the anode side internal flow path 13. That is, the hydrogen storage alloy 6 stores a part of the hydrogen flowing through the anode side internal flow path 13 and generates heat. The heat generated when the hydrogen storage alloy 6 stores hydrogen is transmitted to the entire fuel cell 2. That is, the heat generated by the hydrogen storage alloy 6 is exchanged with the fuel cell 2. When the temperature of the fuel cell 2 is lower than the temperature of the hydrogen storage alloy 6, the temperature of the fuel cell 2 rises due to heat generated by the hydrogen storage of the hydrogen storage alloy 6. When the hydrogen storage alloy 6 is in a state of releasing hydrogen, the hydrogen released from the hydrogen storage alloy 6 is supplied to the membrane electrode assembly 5 and the anode-side internal flow path 13.

  FIG. 3 is a diagram illustrating a configuration example of the fuel cell system according to the present embodiment. As shown in FIG. 3, the fuel cell system according to this embodiment includes a fuel cell stack 1, a hydrogen tank 20, an anode gas passage 21, an anode off gas passage 22, an anode off gas circulation passage 23, an inlet side hydrogen pressure regulating valve 24, and an outlet. Side hydrogen pressure regulating valve 25, gas-liquid separator 26, drain tank 27, exhaust drain valve 28, hydrogen pump 29, filter 30, cathode gas passage 31, air pump 32, inlet side air pressure regulating valve 33, outlet side air pressure regulating valve 34, A cell temperature sensor 35, a pressure sensor 36, an electronic control unit (ECU) 37, an outside air temperature sensor 38, and a cathode off gas passage 39 are provided.

  The hydrogen tank 20 stores hydrogen and supplies hydrogen to the anode gas passage 21. The anode gas passage 21 is a passage for supplying hydrogen to the fuel cell stack 1. Hydrogen supplied to the fuel cell stack 1 is adjusted to a predetermined pressure by the inlet side hydrogen pressure regulating valve 24. That is, the supply pressure of hydrogen to the fuel cell stack 1 is controlled by the opening degree of the inlet side hydrogen pressure regulating valve 24. The opening degree of the inlet side hydrogen pressure regulating valve 24 is controlled by a control signal from the electronic control unit 37.

  Of the hydrogen supplied to the fuel cell stack 1, a gas containing unreacted hydrogen and nitrogen permeated from the catalyst layer 8 (hereinafter referred to as anode off gas) is sent from the fuel cell stack 1 to the anode off gas passage 22. The The anode off gas sent to the anode off gas passage 22 is adjusted to a predetermined pressure by the outlet side hydrogen pressure regulating valve 25. That is, the delivery pressure of the anode off gas to the anode off gas passage 22 is controlled by the opening degree of the outlet side hydrogen pressure regulating valve 25. The opening degree of the outlet-side hydrogen pressure regulating valve 25 is controlled by a control signal from the electronic control unit 37.

  The anode off gas delivered from the fuel cell stack 1 passes through the anode off gas passage 22 and the anode off gas circulation passage 23 and is supplied again to the fuel cell stack 1 together with hydrogen supplied from the hydrogen tank 20. The anode off gas passage 22 supplies the anode off gas sent from the fuel cell stack 1 to the gas-liquid separator 26.

  A gas-liquid separator 26 provided in the anode off-gas passage 22 separates water and hydrogen contained in the anode off-gas sent from the fuel cell stack 1. Hydrogen from which water has been separated by the gas-liquid separator 26 is supplied to the anode gas passage 21 through the anode off-gas circulation passage 23 by the hydrogen pump 29. The anode off gas circulation passage 23 is a passage for supplying hydrogen sent from the hydrogen pump 29 to the anode gas passage 21. The anode off gas passage 22 and the anode off gas circulation passage 23 constitute a circulation path of the fuel cell system.

The drain tank 27 stores the water separated by the gas-liquid separator 26. By opening and closing the exhaust drain valve 28, the water stored in the drain tank 27 is sent to the cathode off gas passage 39, and impurities (N ₂ ) in the anode off gas can be discharged from the circulation path. is there. The water sent to the cathode offgas passage 39 is discharged to the outside air. Further, the exhaust drain valve 28 is appropriately opened and closed so that the water stored in the drain tank 27 does not overflow or the concentration of impurities does not increase.

The cathode gas passage 31 is a passage for supplying air to the fuel cell stack 1. When the air pump 32 is driven, air sucked from outside the fuel cell system is supplied to the fuel cell stack 1 through the filter 30. The air supplied to the fuel cell stack 1 is adjusted to a predetermined pressure by the inlet side air pressure regulating valve 33. That is, the supply pressure of air to the fuel cell stack 1 is controlled by the opening degree of the inlet side air pressure regulating valve 33. The opening degree of the inlet side air pressure regulating valve 33 is controlled by a control signal from the electronic control unit 37.

  Further, unreacted air (also referred to as cathode offgas) among the air supplied to the fuel cell stack 1 is sent from the fuel cell stack 1 to the cathode offgas passage 39. The air sent to the cathode off gas passage 39 is adjusted to a predetermined pressure by the outlet side air pressure regulating valve 34. That is, the delivery pressure of air to the cathode offgas passage 39 is controlled by the opening degree of the outlet side air pressure regulating valve 34. The opening degree of the outlet side air pressure regulating valve 34 is controlled by a control signal from the electronic control unit 37.

The electronic control unit 37 is electrically connected to the inlet side hydrogen pressure regulating valve 24, the outlet side hydrogen pressure regulating valve 25, the inlet side air pressure regulating valve 33, the outlet side air pressure regulating valve 34, the cell temperature sensor 35, the pressure sensor 36 and the outside air temperature sensor 38, respectively. Connected. The electronic control unit 37 includes a CPU (Central Processing Unit), a non-volatile ROM (Read Only Memory), and the like, and the CPU executes various processes according to a control program recorded in the ROM. The electronic control unit 37 controls driving of the cell temperature sensor 35, the pressure sensor 36 and the outside air temperature sensor 38. The electronic control unit 37 controls the drive and opening of the inlet side hydrogen pressure regulating valve 24, the outlet side hydrogen pressure regulating valve 25, the inlet side air pressure regulating valve 33 and the outlet side air pressure regulating valve 34.

  The cell temperature sensor 35 continuously or periodically measures the temperature of the fuel battery cell 2. The temperature data of the fuel cell 2 measured by the cell temperature sensor 35 is sent to the electronic control unit 37. When there are a plurality of fuel cells 2, the temperature data of the fuel cells 2 sent to the electronic control unit 37 may be individual data or average data. The cell temperature sensor 35 may send data to the electronic control unit 37 as the temperature of the plurality of fuel cells 2 by measuring the temperature of the fuel cell stack 1.

  The pressure sensor 36 continuously or periodically measures the pressure in the fuel battery cell 2. More specifically, the pressure sensor 36 continuously or periodically measures the internal pressure of the anode side internal flow path 13 and the internal pressure of the cathode side internal flow path 12. Data of the internal pressure of the anode side internal flow path 13 measured by the pressure sensor 36 is sent to the electronic control unit 37. Further, the internal pressure data of the cathode side internal flow path 12 measured by the pressure sensor 36 is sent to the electronic control unit 37.

  The outside air temperature sensor 38 continuously or periodically measures the outside air temperature. Data on the outside air temperature measured by the outside air temperature sensor 38 is sent to the electronic control unit 37.

  Next, the principle of the warm-up process (hereinafter simply referred to as “warm-up process”) of the fuel cell stack 1 by the fuel cell system according to the present embodiment will be described. The warm-up process is a process for increasing the temperature of the fuel cell 2 in the fuel cell stack 1. During the warm-up process, power generation of the fuel cell stack 1 is not performed. Hereinafter, the process of causing the fuel cell stack 1 to generate power is referred to as power generation processing.

  When performing the warm-up process, the electronic control unit 37 controls the opening degree of the inlet side hydrogen pressure regulating valve 24 and supplies hydrogen from the anode gas passage 21 to the fuel cell stack 1. Then, the electronic control unit 37 controls the opening degree of the outlet side hydrogen pressure regulating valve 25 and stops sending the anode off gas from the fuel cell stack 1 to the anode off gas passage 22.

When hydrogen is supplied from the anode gas passage 21 to the fuel cell stack 1 in a state where the anode off gas delivery from the fuel cell stack 1 to the anode off gas passage 22 is stopped, the internal pressure of the anode side internal flow path 13 of the fuel cell 2 is increased. To rise. That is, the pressure of hydrogen flowing through the anode side internal flow path 13 increases. When the internal pressure of the anode side internal flow path 13 of the fuel cell 2 exceeds a certain value, the hydrogen storage alloy 6 stores the hydrogen flowing through the anode side internal flow path 13 and generates heat. Heat generated by the hydrogen storage alloy 6 is transmitted to the fuel cell 2. When the temperature of the fuel cell 2 is lower than the temperature of the hydrogen storage alloy 6, the temperature of the fuel cell 2 rises.

  The supply of hydrogen to the fuel cell stack 1 in the warm-up process will be described. The supply pressure of hydrogen to the fuel cell stack 1 at the start of the warm-up process is set to a predetermined pressure P1. The predetermined pressure P1 is a lower limit value of the hydrogen supply pressure when the internal pressure of the anode-side internal flow path 13 of the fuel battery cell 2 increases and the hydrogen storage alloy 6 starts to generate heat. The predetermined pressure P1 may be obtained in advance by experiment or simulation. Data of the predetermined pressure P1 is recorded in a ROM provided in the electronic control unit 37.

  The electronic control unit 37 acquires the temperature data of the fuel cell 2 from the cell temperature sensor 35 at predetermined intervals. Further, the electronic control unit 37 may continuously acquire the temperature data of the fuel cell 2 from the cell temperature sensor 35. Then, the electronic control unit 37 determines whether or not the temperature of the fuel battery cell 2 is rising. When the temperature of the fuel cell 2 is rising, the supply pressure of hydrogen to the fuel cell stack 1 is maintained.

  On the other hand, when the temperature of the fuel cell 2 has not risen, the supply pressure of hydrogen to the fuel cell stack 1 is increased. By increasing the supply pressure of hydrogen to the fuel cell stack 1, the applied pressure (supply pressure) of hydrogen to the hydrogen storage alloy 6 increases. Therefore, the calorific value of the hydrogen storage alloy 6 increases compared to before increasing the supply pressure of hydrogen to the fuel cell stack 1.

  The electronic control unit 37 increases the supply pressure of hydrogen to the fuel cell stack 1 by controlling the opening degree of the inlet side hydrogen pressure regulating valve 24. In this case, the supply pressure of hydrogen to the fuel cell stack 1 is increased so that the temperature of the fuel cell 2 increases. That is, the electronic control unit 37 controls the increase in the hydrogen supply pressure to the fuel cell stack 1 while referring to the temperature data of the fuel cell 2 acquired from the cell temperature sensor 35.

  Note that the supply pressure of hydrogen to the fuel cell stack 1 at the start of the warm-up process may be set as high as possible without causing damage to the electrolyte membrane 7 or the like. As the high-pressure hydrogen is supplied to the fuel cell stack 1, the heat generation amount of the hydrogen storage alloy 6 increases, and the temperature of the fuel cell 2 is rapidly increased.

  Further, when the warm-up process is performed, the electronic control unit 37 controls the opening degree of the inlet side air pressure regulating valve 33 and supplies air from the cathode gas passage 31 to the fuel cell stack 1. Then, the electronic control unit 37 controls the opening degree of the outlet side air pressure regulating valve 34 and stops sending the cathode off gas in the cathode off gas passage 39 from the fuel cell stack 1. Note that the cathode offgas delivery from the fuel cell stack 1 to the cathode offgas passage 39 may not be stopped.

  When air is supplied from the cathode gas passage 31 to the fuel cell stack 1 in a state in which the cathode off gas delivery from the fuel cell stack 1 to the cathode off gas passage 39 is stopped, the internal pressure of the cathode side internal flow path 12 of the fuel cell 2 is increased. To rise. That is, the pressure of the air flowing through the cathode side internal flow path 12 of the fuel battery cell 2 increases.

In this case, the internal pressure of the anode side internal flow path 13 and the internal pressure of the cathode side internal flow path 12 are set to the same pressure. When the internal pressure of the anode side internal flow path 13 is higher than the internal pressure of the cathode side internal flow path 12 or when the internal pressure of the cathode side internal flow path 12 is higher than the internal pressure of the anode side internal flow path 13, the electrolyte membrane 7 is damaged. there is a possibility. By making the internal pressure of the anode-side internal flow path 13 and the internal pressure of the cathode-side internal flow path 12 equal, it is possible to avoid damage to the electrolyte membrane 7.

  The electronic control unit 37 acquires the internal pressure data of the anode side internal flow path 13 and the internal pressure data of the cathode side internal flow path 12 from the pressure sensor 36. The electronic control unit 37 compares the internal pressure data of the anode side internal flow path 13 with the internal pressure data of the cathode side internal flow path 12.

  Then, the electronic control unit 37 controls the opening degree of the inlet-side air pressure regulating valve 33, and supplies air so that the internal pressure of the anode-side internal flow path 13 and the internal pressure of the cathode-side internal flow path 12 become the same pressure. Adjust pressure. The electronic control unit 37 performs the same control when air is supplied from the cathode gas passage 31 to the fuel cell stack 1 without stopping the delivery of the cathode off gas from the fuel cell stack 1 to the cathode off gas passage 39. .

  When the warm-up process is finished and the normal operation of the fuel cell stack 1 is started, the electronic control unit 37 controls the opening degree of the outlet side hydrogen pressure regulating valve 25, and the anode from the fuel cell stack 1 to the anode off gas passage 22 is controlled. Start off-gas delivery. Then, the electronic control unit 37 controls the opening degree of the outlet side air pressure regulating valve 34 and starts sending the cathode off gas from the fuel cell stack 1 to the cathode off gas passage 39.

  Note that hydrogen may be supplied from the anode gas passage 21 to the fuel cell stack 1 in a state where the sending of the anode off gas from the fuel cell stack 1 to the anode off gas passage 22 is not stopped. In this case, air is supplied from the cathode gas passage 31 to the fuel cell stack 1 without stopping the delivery of the cathode offgas from the fuel cell stack 1 to the cathode offgas passage 39.

  In the above case, the electronic control unit 37 controls the air supply pressure so that the air supply pressure to the fuel cell stack 1 is the same as the hydrogen supply pressure. About the supply pressure of the air to the fuel cell stack 1, the opening degree of the inlet side air pressure regulating valve 33 is adjusted so that it becomes a value necessary and sufficient for the fuel cell 2 to be heated by the heat generation of the hydrogen storage alloy 6. do it.

  FIG. 4 is a flowchart showing a processing flow of the fuel cell system according to the present embodiment. The fuel cell system according to the present embodiment executes the process of FIG. 4 when a start start process is performed on the fuel cell system. For example, when the ignition switch is turned on, the electronic control unit 37 may determine that there has been an instruction to start the fuel cell system, and may execute the processing of FIG.

  The cell temperature sensor 35 starts measuring the temperature of the fuel battery cell 2. The outside air temperature sensor 38 starts measuring the outside air temperature (S01). The measurement of the temperature of the fuel cell 2 by the cell temperature sensor 35 is started by a start signal from the electronic control unit 37. Further, the start of the measurement of the outside air temperature by the outside air temperature sensor 38 is performed by a start signal from the electronic control unit 37. The electronic control unit 37 acquires the temperature data of the fuel cell 2 measured by the cell temperature sensor 35 from the cell temperature sensor 35. In addition, the electronic control unit 37 acquires the outside temperature data measured by the outside temperature sensor from the outside temperature sensor 38.

Then, the electronic control unit 37 determines whether or not the temperature of the fuel battery cell 2 is equal to or lower than a predetermined threshold T1 (S02). For example, the predetermined threshold T1 may be set to 0 ° C. If the water existing inside the fuel cell 2 is frozen, the supply of air to the catalyst layer 8 and the supply of hydrogen to the catalyst layer 9 are hindered, and the power generation efficiency is reduced or power generation is not performed. Therefore, the predetermined threshold value T1 may be an upper limit value of a temperature range in which water existing in the fuel battery cell 2 is frozen. What is necessary is just to obtain | require previously the temperature range which the water which exists in the fuel cell 2 freezes by experiment or simulation.

  When the temperature of the fuel cell 2 is equal to or lower than the predetermined threshold T1 (YES in the process of S02), the electronic control unit 37 starts a warm-up process (S03).

  On the other hand, when the temperature of the fuel cell 2 is not equal to or lower than the predetermined threshold T1 (NO in S02), the electronic control unit 37 determines whether or not the outside air temperature is equal to or lower than the predetermined threshold T2 (S04). For example, the predetermined threshold T2 may be set to 0 ° C. The predetermined threshold value T2 may be an upper limit value of a temperature range in which water existing in the fuel battery cell 2 is frozen.

  When the outside air temperature is equal to or lower than the predetermined threshold T2 (YES in the process of S04), the process proceeds to S03. That is, the electronic control unit 37 starts a warm-up process.

  On the other hand, when the outside air temperature is not equal to or lower than the predetermined threshold T2 (NO in the process of S04), the electronic control unit 37 starts the normal operation of the fuel cell stack 1 without performing the warm-up process (S05).

  When starting the warm-up process, the electronic control unit 37 acquires the temperature data of the fuel cell 2 measured by the cell temperature sensor 35 from the cell temperature sensor 35. Next, the electronic control unit 37 determines whether or not the temperature of the fuel cell 2 is equal to or higher than a predetermined threshold T3 (S06).

  The predetermined threshold T3 may be a lower limit value of a temperature range in which water existing in the fuel battery cell 2 does not freeze. Alternatively, the predetermined threshold T3 may be a lower limit value of a temperature range in which a rated output can be obtained from the fuel cell stack 1. Further, the predetermined threshold T3 is set between the lower limit value of the temperature range in which the rated output can be obtained from the fuel cell stack 1 and the lower limit value of the temperature range in which the water existing in the fuel cell 2 is not frozen. Also good.

  When the temperature of the fuel cell 2 is equal to or higher than the predetermined threshold T3 (YES in the process of S06), the electronic control unit 37 ends the warm-up process (S07). Then, the electronic control unit 37 starts normal operation of the fuel cell stack 1 (S08).

  On the other hand, when the temperature of the fuel battery cell 2 is not equal to or higher than the predetermined threshold T3 (NO in the process of S07), the electronic control unit 37 continues to operate until the temperature of the fuel battery cell 2 becomes equal to or higher than the predetermined threshold T3. The temperature data acquisition and the determination of whether or not the temperature of the fuel cell 2 is equal to or higher than a predetermined threshold T3 are repeated.

  In the process of the electronic control unit 37, both the processes of S02 and S04 in FIG. 4 are not essential, and the warm-up process may be started according to only one of the determinations.

  According to the present embodiment, when the warm-up process is started, air having a pressure at which the hydrogen storage alloy 6 is in a heat generating state is supplied to the fuel cell stack 1. The fuel cell 2 rises in temperature due to the heat generated by the hydrogen storage alloy 6. Therefore, the fuel cell stack 1 can be quickly warmed up even at a low temperature when the water present in the fuel cell 2 is frozen. The present embodiment has a simple structure in which the hydrogen storage alloy 6 is provided in the fuel battery cell 2, and the fuel cell system is complicated because the pressure of hydrogen supplied to the fuel battery cell 2 is controlled. Without this, the fuel cell 2 can be raised to a desired temperature.

<Modification>
In the process of S07 in the process of the fuel cell system shown in FIG. 4, when the temperature of the fuel cell 2 is equal to or higher than a predetermined threshold T3, the warm-up process is terminated. Alternatively, when the elapsed time from the start of the warm-up process reaches the predetermined time h, the warm-up process may be terminated.

  In this case, the supply pressure of hydrogen supplied to the fuel cell stack 1 at the start of the warm-up process is changed to the predetermined pressure P2. The predetermined pressure P2 is a value set as high as possible within a range in which the supply pressure of hydrogen supplied to the fuel cell stack 1 does not cause the electrolyte membrane 7 to be damaged. The predetermined pressure P2 may be obtained in advance by experiments or simulations. Data of the predetermined pressure P2 is recorded in a ROM provided in the electronic control unit 37.

  Here, the electronic control unit 37 may calculate the predetermined time h as follows. First, the amount of heat HM1 required to raise the temperature of the fuel cell 2 from the temperature corresponding to the predetermined threshold T1 to the temperature corresponding to the predetermined threshold T3 is calculated. For example, the amount of heat HM1 is calculated by multiplying the amount of heat (kJ / ° C.) necessary to raise the temperature of the fuel cell 2 by subtracting the predetermined threshold T1 from the predetermined threshold T3.

  Then, the predetermined time h is calculated by dividing the heat quantity HM1 (kJ) by the heat quantity HM2 (kJ / h). The amount of heat HM2 (kJ / h) is the heat generation amount (kJ) of the hydrogen storage alloy 6 per unit time when hydrogen is supplied to the fuel cell stack 1 at a predetermined pressure P2. The amount of heat HM2 (kJ / h) may be obtained in advance by experiment or simulation. Data of the heat quantity HM2 (kJ / h) is recorded in a ROM provided in the electronic control unit 37.

It is a perspective view which shows the fuel cell 2 which the fuel cell stack 1 with which the fuel cell system which concerns on this embodiment is provided has. It is a top view of the fuel cell 2 which the fuel cell stack 1 with which the fuel cell system which concerns on this embodiment is provided has. It is a figure which shows the structural example of the fuel cell system which concerns on this embodiment. It is a flowchart which shows the flow of a process of the fuel cell system which concerns on this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell stack 2 Fuel cell 3, 4 Separator 5 Membrane electrode assembly (MEA)
6 Hydrogen storage alloy 7 Electrolyte membrane 8, 9 Catalyst layer 10, 11 Gas diffusion layer 12 Cathode side internal flow path 13 Anode side internal flow path 20 Hydrogen tank 21 Anode gas path 22 Anode off gas path 23 Anode off gas circulation path 24 Inlet side hydrogen Pressure regulating valve 25 Outlet side hydrogen regulating valve 26 Gas-liquid separator 27 Drain tank 28 Exhaust drain valve 29 Hydrogen pump 30 Filter 31 Cathode gas passage 32 Air pump 33 Inlet side air regulating valve 34 Outlet side air regulating valve 35 Cell temperature sensor 36 Pressure sensor 37 Electronic Control Unit (ECU)
38 Outside temperature sensor 39 Cathode off-gas passage

Claims (5)

A fuel cell that generates electricity by an electrochemical reaction between hydrogen and oxygen;
Hydrogen storage means for storing hydrogen;
A hydrogen storage alloy that generates heat by storing a part of the hydrogen supplied to the fuel cell and is heat-exchangeable with the fuel cell;
First measuring means for measuring the temperature of the fuel cell;
Control means for starting the supply of hydrogen from the hydrogen storage means to the fuel cell according to the temperature of the fuel cell,
The control means is a fuel cell system that controls the supply pressure of hydrogen from the hydrogen storage means to the fuel cell according to the temperature of the fuel cell after the supply of hydrogen to the fuel cell is started. An air supply means for supplying air containing oxygen to the fuel cell;
2. The fuel according to claim 1, wherein the control unit controls a supply pressure of air from the air supply unit to the fuel cell so that a hydrogen pressure in the fuel cell and an air pressure become the same pressure. Battery system. Further comprising stop means for stopping delivery of air sent from the fuel cell;
The fuel cell system according to claim 1, wherein the hydrogen storage alloy is provided in the fuel cell. An air supply means for supplying air containing oxygen to the fuel cell;
3. The fuel according to claim 1, wherein the control unit controls the supply pressure of air from the air supply unit to the fuel cell to be the same as the supply pressure of hydrogen from the hydrogen storage unit to the fuel cell. Battery system. A second measuring means for measuring the outside air temperature;
5. The fuel cell system according to claim 1, wherein the control unit starts supplying hydrogen from the hydrogen storage unit to the fuel cell in accordance with the outside air temperature. 6.

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