JP2012038618A - Starting method of fuel cell system - Google Patents

Abstract

A gas replacement process at start-up can be performed in a short time by a particularly small and economical system.
A starting method of a fuel cell system includes a step of detecting by a controller that a driver carrying a portable device has approached the vehicle from the outside, and the controller to the driver's vehicle. The process of starting the decompression process of the oxidant gas flow path 34 and the fuel gas flow path 36 in the fuel cell stack 12 before the ignition switch 86 that enables the vehicle to travel is turned on when the proximity signal is detected. And have.
[Selection] Figure 1

Description

  The present invention has an oxidant gas flow path for supplying an oxidant gas to the cathode side electrode and a fuel gas flow path for supplying a fuel gas to the anode side electrode, and an electrochemical reaction between the oxidant gas and the fuel gas. The present invention relates to a method for starting a fuel cell system in which a fuel cell for generating electricity is mounted on a vehicle.

  A fuel cell supplies a fuel gas (mainly hydrogen-containing gas) and an oxidant gas (mainly oxygen-containing gas) to the anode-side electrode and the cathode-side electrode and causes them to react electrochemically. It is a system that obtains electrical energy.

  For example, a polymer electrolyte fuel cell includes a power generation cell in which an electrolyte membrane / electrode structure provided with an anode side electrode and a cathode side electrode is sandwiched between separators on both sides of an electrolyte membrane made of a polymer ion exchange membrane. ing. This type of power generation cell is normally used as a fuel cell stack by alternately laminating a predetermined number of electrolyte membrane / electrode structures and separators. The fuel cell stack is generally mounted on a fuel cell vehicle such as a fuel cell vehicle.

  In this type of fuel cell stack, when power generation (operation) is stopped, the supply of fuel gas and oxidant gas to the fuel cell stack is stopped, while the fuel gas remains on the anode side electrode, The oxidant gas remains on the cathode side electrode. For this reason, when the fuel cell stack is stopped for a long time, the air that has permeated the electrolyte membrane from the cathode side moves to the anode side, and air exists in the cathode side electrode and the anode side electrode.

  When the fuel cell stack is started in this state, when the supply of fuel gas to the anode side electrode is started, hydrogen and air are mixed, so that the cathode side electrode tends to be at a high potential. As a result, there is a problem in that the power generation performance is reduced due to the performance deterioration of the electrode catalyst layer of the cathode side electrode.

  Thus, for example, a method for starting a fuel cell system disclosed in Patent Document 1 is known. In this starting method, at least the oxidant gas remaining in the fuel gas flow path is sucked to depressurize the fuel gas flow path, the fuel gas is supplied to the fuel gas flow path, and the oxidant gas flow path is supplied. Supplying the oxidant gas to generate power in the fuel cell.

  Thereby, the cathode side electrode does not become a high potential, and the start-up process of the fuel cell is efficiently performed.

JP 2009-163919 A

  By the way, in particular, in an in-vehicle fuel cell system, it is desired to quickly start the fuel cell, and it is necessary to complete the decompression process in a short time. For this reason, it is conceivable to set the capacity of the decompression pump large, but the decompression pump becomes large. As a result, there is a problem that an installation space for the decompression pump cannot be secured in the vehicle, and energy consumption increases.

  Furthermore, when a large pressure reducing pump is set in the motor room (so-called engine room) and the fuel cell is arranged under the floor, the connecting pipe becomes long and the pressure reducing space is enlarged. At that time, in order to suppress the expansion of the decompression space, it is necessary to provide a large dedicated valve in the immediate vicinity of the fuel cell stack.

  Furthermore, in order to discharge the hydrogen remaining in the anode system on the fuel gas flow path side while the vehicle is stopped, it is necessary to route an exhaust line from the decompression pump to the diluter. Therefore, there is a problem that the layout of the entire system is considerably complicated.

  The present invention solves this type of problem, and provides a starting method of a fuel cell system that can perform a gas replacement process at the time of starting in a short time by a particularly small and economical system. Objective.

  The present invention has an oxidant gas flow path for supplying an oxidant gas to the cathode side electrode and a fuel gas flow path for supplying a fuel gas to the anode side electrode, and an electrochemical reaction between the oxidant gas and the fuel gas. The present invention relates to a method for starting a fuel cell system in which a fuel cell for generating electricity is mounted on a vehicle.

  In this starting method, a step of detecting whether or not a passenger has approached the vehicle from the outside, and a start switch that enables the vehicle to travel when the proximity signal of the passenger to the vehicle is detected are turned on. Before starting the gas replacement process in the fuel cell.

  In this starting method, it is preferable that the gas replacement process includes a step of sucking the oxidant gas remaining in the fuel gas passage with a decompression pump to decompress the fuel gas passage.

  In the present invention, the gas replacement process in the fuel cell is started when the passenger approaches the vehicle from the outside. For this reason, the gas replacement process is performed until the passenger sits on the seat and turns on the activation switch (so-called ignition switch).

  Therefore, the startup time of the fuel cell system can be effectively shortened, and a desired power generation state can be secured quickly and stably. In addition, the pumps can be effectively reduced in size, space saving, and weight, and the power consumption can be satisfactorily suppressed.

1 is a schematic configuration diagram of a fuel cell system according to an embodiment of the present invention. It is a flowchart explaining the starting method which concerns on embodiment of this invention. It is a timing chart in the starting method. It is explanatory drawing at the time of pressure reduction of the said fuel cell system. It is explanatory drawing at the time of the decompression stop of the said fuel cell system. It is explanatory drawing at the time of the electric power generation of the said fuel cell system. It is explanatory drawing at the time of the electric power generation stop of the said fuel cell system. It is explanatory drawing at the time of pressure reduction of the said fuel cell system. It is explanatory drawing at the time of air injection of the said fuel cell system. It is a timing chart which starts the conventional pressure reduction process. It is a timing chart which starts the pressure reduction process of this invention.

  FIG. 1 is a schematic configuration diagram of a fuel cell system 10 to which a starting method according to an embodiment of the present invention is applied. Although not shown, the fuel cell system 10 is mounted on a fuel cell vehicle such as a fuel cell vehicle.

  The fuel cell system 10 includes a fuel cell stack 12, an oxidant gas supply device 14 for supplying an oxidant gas to the fuel cell stack 12, a fuel gas supply device 16 for supplying a fuel gas to the fuel cell stack 12, By wireless communication, a decompression device 18 for sucking an oxidant gas passage 34 and a fuel gas passage 36, which will be described later, a dilution device 20 for diluting the fuel gas with air, a controller 21 for controlling the entire fuel cell system 10, and And a portable device that is connected to the controller and detects whether or not a passenger (for example, a driver) has approached the vehicle from the outside.

  The fuel cell stack 12 is configured by stacking a plurality of fuel cells 22. Each fuel cell 22 includes an electrolyte membrane / electrode structure 30 in which a solid polymer electrolyte membrane 24 is sandwiched between a cathode side electrode 26 and an anode side electrode 28. The electrolyte membrane / electrode structure 30 is paired with a pair of separators 32a, Hold by 32b. Between the electrolyte membrane / electrode structure 30 and the separator 32a, an oxidant gas channel 34 for supplying an oxidant gas to the cathode side electrode 26 is formed, and the electrolyte membrane / electrode structure 30 and the separator 32b are formed. A fuel gas passage 36 for supplying fuel gas to the anode side electrode 28 is formed between the two.

  At one end in the stacking direction of the fuel cell stack 12, an oxidant gas inlet communication hole 38a for supplying an oxidant gas such as air (oxygen-containing gas) to the oxidant gas flow path 34, and a fuel such as a hydrogen-containing gas A fuel gas inlet communication hole 40 a for supplying gas to the fuel gas flow path 36 is formed. At the other end in the stacking direction of the fuel cell stack 12, an oxidant gas outlet communication hole 38 b for discharging the oxidant gas from the oxidant gas flow path 34 and a fuel gas for discharging from the fuel gas flow path 36 are provided. A fuel gas outlet communication hole 40b is formed.

  The oxidant gas supply device 14 includes an air pump 42 that compresses and supplies air from the atmosphere, and the air pump 42 is disposed in the air supply flow path 44. An air filter 46 is disposed in the air supply channel 44 on the upstream side of the air pump 42. The air supply channel 44 communicates with the oxidant gas inlet communication hole 38 a of the fuel cell stack 12, and a dilution channel 48 is branched from the downstream side of the air pump 42, and the dilution channel 48 is connected to the dilution device 20. The Although not shown, a humidifier is disposed in the middle of the air supply channel 44.

  The oxidant gas supply device 14 includes an air discharge channel 50 that communicates with the oxidant gas outlet communication hole 38b. The air discharge channel 50 is connected to the dilution device 20.

The fuel gas supply device 16 includes a hydrogen tank (H ₂ tank) 52 that stores high-pressure hydrogen (hydrogen-containing gas). The hydrogen tank 52 is connected to a fuel gas inlet of the fuel cell stack 12 via a hydrogen supply channel 54. It communicates with the communication hole 40a. The hydrogen supply channel 54 is provided with a regulator 56 and an ejector 58, and the downstream of the ejector 58 and the air supply channel 44 can communicate with each other via a branch channel 59.

  An off gas passage 60 communicates with the fuel gas outlet communication hole 40 b and a hydrogen circulation passage 62 communicates with the off gas passage 60. The off-gas flow path 60 is connected to the diluting device 20, while the hydrogen circulation path 62 is connected to the ejector 58.

  The ejector 58 supplies the hydrogen gas supplied from the hydrogen tank 52 to the fuel cell stack 12 through the hydrogen supply flow path 54, and exhaust gas containing unused hydrogen gas that has not been used in the fuel cell stack 12. Then, the gas is sucked from the hydrogen circulation path 62 and supplied again as fuel gas to the fuel cell stack 12.

  The decompression device 18 individually includes a first decompression pump 66 a that sucks the oxidant gas passage 34 and a second decompression pump 66 b that sucks the fuel gas passage 36. The first pressure reducing pump 66a is disposed in the first pressure reducing flow path 68a, and the first pressure reducing flow path 68a is connected to the air discharge flow path 50 and the diluting device 20. The second decompression pump 66b is disposed in the second decompression flow path 68b, and the second decompression flow path 68b is connected to the off-gas flow path 60 and the diluting device 20.

  The fuel cell system 10 is provided with a first on-off valve 70a to a tenth on-off valve 70j. Specifically, the first opening / closing valve 70 a is disposed in the branch flow path 59, and the second opening / closing valve 70 b is disposed in the air supply flow path 44 at a position downstream of the branch flow path 59. The third on-off valve 70 c is disposed in the hydrogen supply channel 54 between the regulator 56 and the ejector 58.

  The fourth on-off valve 70d is disposed in the off-gas passage 60 in the vicinity of the fuel gas outlet communication hole 40b, while the fifth on-off valve 70e is in the off-gas passage 60 in the vicinity of the diluting device 20. Arranged. The sixth on-off valve 70f is disposed in the air discharge channel 50 in the vicinity of the oxidant gas outlet communication hole 38b, and the seventh on-off valve 70g is in the vicinity of the dilution device 20 in the air discharge channel 50. It arranges (positioned downstream of the 1st decompression flow path 68a).

  The eighth open / close valve 70h is disposed upstream of the first pressure reducing pump 66a in the first pressure reducing flow path 68a, while the ninth open / close valve 70i is disposed in the second pressure reducing flow path 68b of the second pressure reducing pump 66b. Located upstream. The tenth open / close valve 70j is disposed in the dilution flow path 48.

  In the air supply channel 44, a first pressure sensor 72a is disposed between the second opening / closing valve 70b and the oxidant gas inlet communication hole 38a. In the hydrogen supply channel 54, a second pressure sensor 72b is disposed in the vicinity of the fuel gas inlet communication hole 40a. The first pressure sensor 72a detects the reduced pressure state of the oxidant gas flow path 34, and the second pressure sensor 72b detects the reduced pressure state of the fuel gas flow path 36.

  For example, a load 74 such as a vehicle drive motor or an air pump drive motor is provided in the fuel cell stack 12 through a switch 76 so as to be electrically disconnected and connectable.

  The controller 21 includes a communication circuit 80 connected to the antenna 78, while the portable device 23 includes a communication circuit 84 connected to the antenna 82. The controller 21 transmits a calling signal at predetermined intervals within a predetermined range including the vehicle (not shown) via the communication circuit 80 and the antenna 78, and a response returned from the portable device 23 in response to the calling signal. Receive a signal.

  The controller 21 determines whether the portable device 23 is approaching the vehicle based on the received response signal. Furthermore, the controller 21 unlocks the vehicle door based on the information included in the received response signal and starts a gas replacement process (described later) in the fuel cell stack 12.

  For example, an ignition switch 86 is connected to the controller 21 as an activation switch that shifts the stopped vehicle to a state where it can run.

  The operation of the fuel cell system 10 configured as described above will be described below with reference to the flowchart shown in FIG. 2 and the timing chart shown in FIG. 3 in relation to the starting method according to the embodiment of the present invention.

  In the fuel cell system 10, as will be described later, the oxidant gas flow paths 34 and the fuel gas flow paths 36 of the fuel cell stack 12 are filled with the oxidant gas in a stopped state.

  Therefore, when the driver (passenger) has the portable device 23 and approaches the vehicle, the controller 21 receives a response signal returned from the portable device 23 via the communication circuit 80 and the antenna 78. For this reason, the controller 21 determines whether or not the portable device 23 is approaching the vehicle. When the controller 21 receives an approach signal from the portable device 23 to the vehicle (YES in step S1), the controller 21 proceeds to step S2. .

  In step S <b> 2, the oxidant gas passage 34 and the fuel gas passage 36 are decompressed (at least, the fuel gas passage 36 is decompressed). Specifically, as shown in FIGS. 3 and 4, the first on-off valve 70a to the third on-off valve 70c, the fifth on-off valve 70e, the seventh on-off valve 70g, and the tenth on-off valve 70j are closed, The fourth on-off valve 70d, the sixth on-off valve 70f, the eighth on-off valve 70h, and the ninth on-off valve 70i are opened. In this state, the first decompression pump 66a and the second decompression pump 66b constituting the decompression device 18 are driven.

  The first decompression pump 66a communicates with the oxidant gas flow path 34, and the oxidant gas flow path 34 is sucked. Therefore, since the oxidant gas remaining in the oxidant gas flow path 34 is sucked by the first pressure reduction pump 66a and discharged to the diluting device 20, the oxidant gas flow path 34 is depressurized. The reduced pressure state of the oxidant gas flow path 34 is detected by the first pressure sensor 72a.

  On the other hand, the second decompression pump 66 b sucks the oxidant gas remaining in the fuel gas flow path 36 and discharges the fuel gas to the dilution device 20. Thereby, the fuel gas flow path 36 is decompressed. The reduced pressure state of the fuel gas passage 36 is detected by the second pressure sensor 72b.

  After the oxidant gas flow path 34 and the fuel gas flow path 36 reach a predetermined pressure reduction state, the pressure reduction is stopped (step S3) and held for a predetermined time. This decompression stop state is maintained by closing the eighth on-off valve 70h and the ninth on-off valve 70i as shown in FIGS.

  Next, when the ignition switch 86 is turned on (step S4), the process proceeds to step S5, and fuel gas is supplied to each fuel gas flow path 36 of the fuel cell stack 12. Then, after the fuel gas supply is started and a predetermined time has elapsed, the supply of the oxidant gas to each oxidant gas flow path 34 is started (step S6).

  Specifically, as shown in FIGS. 3 and 6, when the time T elapses after the third on-off valve 70c is opened, the second on-off valve 70b and the seventh on-off valve 70g are opened, The 5 on-off valve 70e is opened intermittently (or only by a predetermined opening).

  Accordingly, first, the fuel gas (hydrogen gas) is supplied from the hydrogen tank 52 to the hydrogen supply channel 54. The fuel gas is decompressed by the regulator 56 and then supplied to each fuel gas flow path 36 of the fuel cell stack 12. The fuel gas discharged from the fuel gas flow path 36 is sucked into the ejector 58 through the hydrogen circulation path 62 and supplied again to the fuel gas flow path 36 from the hydrogen supply flow path 54.

  Thereafter, since the air pump 42 is driven, air (oxidant gas) is supplied from the air supply channel 44 to each oxidant gas channel 34 of the fuel cell stack 12. The air discharged from the oxidant gas flow path 34 is sent to the dilution device 20.

  Therefore, the switch 76 is closed, and the load 74 is electrically connected to the fuel cell stack 12. Thereby, the electric power generation by the fuel cell stack 12 is started (step S7).

  During this power generation, the oxidant gas is sent to the oxidant gas flow path 34 of each fuel cell 22 and is supplied along each cathode side electrode 26. On the other hand, the fuel gas is supplied to each fuel gas flow path 36 of the fuel cell 22 and supplied along each anode side electrode 28. For this reason, electric power is generated by the electrochemical reaction between the air supplied to the cathode side electrode 26 and the fuel gas supplied to the anode side electrode 28.

  When power generation by the fuel cell stack 12 is stopped (step S8), the fuel cell stack 12 is electrically disconnected from the load 74 by opening the switch 76. For this reason, the power supply from the fuel cell stack 12 to the outside is stopped. On the other hand, as shown in FIGS. 3 and 7, the second on-off valve 70b and the third on-off valve 70c are closed, and the supply of air and fuel gas to the fuel cell stack 12 is stopped.

  Furthermore, it progresses to step S9 and the pressure reduction process of the oxidant gas flow path 34 and the fuel gas flow path 36 is performed. During this decompression process, as shown in FIGS. 3 and 8, the fifth on-off valve 70e and the seventh on-off valve 70g are closed, while the eighth on-off valve 70h and the ninth on-off valve 70i are opened.

  Therefore, the oxidant gas flow path 34 is sucked under the action of the first pressure reducing pump 66a, and the oxidant gas remaining in the oxidant gas flow path 34 is discharged to the diluting device 20, whereby the oxidant gas The flow path 34 is depressurized. Further, under the action of the second pressure reducing pump 66b, the fuel gas passage 36 is sucked, and the fuel gas remaining in the fuel gas passage 36 is discharged to the diluting device 20, whereby the fuel gas passage 36 is Depressurized.

  At this time, since the air remaining in the oxidant gas flow path 34 is introduced into the dilution device 20, the fuel gas discharged from the fuel gas flow path 36 can be diluted well. Alternatively, the tenth opening / closing valve 70j may be opened and the air pump 42 may be driven to supply dilution air to the dilution device 20.

  When the oxidant gas flow path 34 and the fuel gas flow path 36 reach a predetermined pressure reduction state, the pressure reduction processing is stopped (step S10). In step S10, as shown in FIGS. 3 and 5, the eighth on-off valve 70h and the ninth on-off valve 70i are closed. As a result, the oxidant gas flow path 34 and the fuel gas flow path 36 are maintained in a predetermined reduced pressure state, and an air charging process is performed after a predetermined time has elapsed.

  Specifically, as shown in FIGS. 3 and 9, the fourth on-off valve 70d and the sixth on-off valve 70f are closed, while the first on-off valve 70a and the second on-off valve 70b are opened, and the air pump 42 is driven. Is done. Accordingly, air is supplied to the air supply passage 44 via the air pump 42. This air is supplied to each oxidant gas flow path 34 of the fuel cell stack 12 and is sent to the hydrogen supply flow path 54 via the branch flow path 59, and each fuel gas flow path 36 of the fuel cell stack 12. (Step S11).

  Then, after the oxidant gas pressure filled in the fuel gas flow path 36 and the oxidant gas flow path 34 reaches atmospheric pressure, the first on-off valve 70a and the second on-off valve 70b are closed so that the fuel The battery system 10 as a whole is stopped (all stopped) (step S12).

  In this case, in this embodiment, when the driver holds the portable device 23 and approaches the vehicle, the decompression processing of the oxidant gas passage 34 and the fuel gas passage 36 is started via the controller 21. For this reason, the gas replacement process is performed until the driver reaches the seat in the vehicle and turns on the ignition switch 86.

  That is, conventionally, as shown in FIG. 10, after the driver unlocks the vehicle door and sits on the driver seat and then turns on the ignition switch 86, the oxidant gas flow path 34 and the fuel gas flow are turned on. The pressure reducing process for the path 36 is started. On the other hand, in this embodiment, as shown in FIG. 11, the decompression process of the oxidant gas flow path 34 and the fuel gas flow path 36 is started at the same time when the vehicle door is unlocked.

  Therefore, in the present embodiment, the startup time of the fuel cell system 10 can be effectively shortened, and a desired power generation state can be secured quickly and stably. In addition, the first decompression pump 66a and the second decompression pump 66b do not need to have a large capacity in order to perform the decompression process in a short time. As a result, the first decompression pump 66a and the second decompression pump 66b can be effectively reduced in size, space-saving, and light weight, and the power consumption can be suppressed.

  In the present embodiment, the controller 21 receives a response signal returned from the portable device 23 to determine whether or not the portable device 23 is approaching the vehicle. Although the gas replacement process is started, the present invention is not limited to this. For example, the driver may start the gas replacement process in the fuel cell stack 12 by turning on an unlocking switch (not shown) or the like provided in the portable device 23.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell system 12 ... Fuel cell stack 14 ... Oxidant gas supply device 16 ... Fuel gas supply device 18 ... Decompression device 20 ... Dilution device 21 ... Controller 22 ... Fuel cell 23 ... Portable device 24 ... Solid polymer electrolyte membrane
26 ... Cathode side electrode 28 ... Anode side electrode 30 ... Electrolyte membrane / electrode structure 32a, 32b ... Separator 34 ... Oxidant gas flow path 36 ... Fuel gas flow path 38a ... Oxidant gas inlet communication hole 38b ... Oxidant gas inlet Communication hole 40a ... Fuel gas inlet communication hole 40b ... Fuel gas outlet communication hole 42 ... Air pump 44 ... Air supply channel 48 ... Dilution channel 50 ... Air discharge channel 52 ... Hydrogen tank 54 ... Hydrogen supply channel 60 ... Off gas flow Path 62 ... Hydrogen circulation path 66a, 66b ... Pressure reducing pump 68a, 68b ... Pressure reducing flow path 70a-70j ... Open / close valve 72a, 72b ... Pressure sensor 78, 82 ... Antenna 80, 84 ... Communication circuit 86 ... Ignition switch

Claims (2)

A fuel cell having an oxidant gas flow path for supplying an oxidant gas to the cathode side electrode and a fuel gas flow path for supplying a fuel gas to the anode side electrode, and generating electric power by an electrochemical reaction of the oxidant gas and the fuel gas Is a method of starting a fuel cell system mounted on a vehicle,
Detecting whether a passenger has approached the vehicle from the outside;
A step of starting a gas replacement process in the fuel cell before a start switch that enables the vehicle to travel when the proximity signal of the passenger to the vehicle is detected;
A start method for a fuel cell system, comprising:   2. The start-up method according to claim 1, wherein the gas replacement process includes a step of sucking the oxidant gas remaining in the fuel gas passage with a decompression pump to decompress the fuel gas passage. To start the fuel cell system.

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