JP2011015537A - Fuel cell vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell vehicle capable of shielding a stack from a discharge resistor even if a discharge contactor falls into on-failure.SOLUTION: A fuel cell vehicle 1 includes a reverse flow preventing diode 612 which is provided to a positive electrode power supply line 61 to prevent a reverse flow of a current from a motor generator 20 to a stack 10, a discharge circuit 65 which connects a point between a positive electrode fuel cell contactor 611 and the reverse flow preventing diode 612 with a point on a negative electrode power supply line 62 between a negative electrode fuel cell contactor 621 and the stack 10 side, and a discharge resistor 654 and a discharge contactor 652 provided in the discharge circuit 65. At the start of reactive gas supply to the stack 10, an ECU80 connects the discharge contactor 652 and further the positive electrode fuel cell contactor 611, and consumes the generated power of the stack 10.

Description

  The present invention relates to a fuel cell vehicle. Specifically, the present invention relates to a fuel cell vehicle having a discharge resistor.

  In recent years, a fuel cell vehicle equipped with a fuel cell as a power source has attracted attention. The fuel cell vehicle includes, for example, a fuel cell that generates a power by chemically reacting a reaction gas, and a reaction gas supply device that supplies the reaction gas to the fuel cell via a reaction gas channel.

  The fuel cell has, for example, a stack structure in which several tens to several hundreds of cells are stacked. Here, each cell is configured by sandwiching a membrane electrode structure (MEA) between a pair of separators. The membrane electrode structure includes two electrodes, an anode electrode (cathode) and a cathode electrode (anode), and these electrodes. And a solid polymer electrolyte membrane sandwiched between the two.

  When hydrogen gas as a reaction gas is supplied to the anode electrode of the fuel cell and air containing oxygen as a reaction gas is supplied to the cathode electrode, power is generated by an electrochemical reaction. Since only harmless water is basically generated at the time of power generation, fuel cell vehicles are attracting attention from the viewpoint of environmental impact and utilization efficiency.

  By the way, if the reaction gas is continuously supplied to the fuel cell in a no-load state, that is, in a state in which no current is drawn from the fuel cell, the fuel cell becomes a high voltage state. However, since the fuel cell deteriorates in a high voltage state, it is necessary to prevent the fuel cell from being in a high voltage state as much as possible and suppress the deterioration. Therefore, conventionally, a discharge resistor is provided as an extra load separately from the vehicle load for generating the power of an automobile such as a motor, and this discharge resistor and the fuel cell are connected appropriately to consume the power generated by the fuel cell. This prevents the fuel cell from entering a high voltage state (see Patent Document 1).

  More specifically, in the fuel cell system disclosed in Patent Document 1, the discharge resistor is connected to the fuel cell in parallel with the vehicle load. Still further, a discharge contactor is connected in series with the discharge resistor as means for connecting or disconnecting the discharge resistor and the fuel cell.

JP 2007-335126 A

  However, in such a fuel cell system, the means for cutting off the discharge resistor and the fuel cell is basically only the discharge contactor. Therefore, when this discharge contactor is on-failed, the discharge resistor always generates heat, The generated power of the fuel cell is not only consumed more than necessary, but the discharge resistance may be deteriorated.

  The present invention has been made in view of the above-described problems, and is a fuel cell vehicle equipped with a discharge resistor and a discharge contactor, which cuts off the fuel cell and the discharge resistor even when the discharge contactor is on-failed. An object of the present invention is to provide a fuel cell vehicle that can be used.

  In order to achieve the above object, a first aspect of the present invention is directed to a fuel cell (for example, a fuel cell stack 10 described later) that generates power using a reaction gas, and a motor / generator (for example, a motor described later) connected to the fuel cell. A fuel cell vehicle (for example, a fuel cell vehicle 1 to be described later) that travels by driving the motor / generator with electric power generated by the fuel cell. The fuel cell vehicle has a positive fuel cell contactor (for example, described later) provided on a positive power supply line (for example, positive power supply line 61 to be described later) connecting the positive electrode of the fuel cell and the positive electrode of the motor / generator. A negative electrode fuel cell contactor (for example, a negative electrode power supply line 62 to be described later) connected to a negative electrode of the fuel cell and a negative electrode of the motor / generator. A negative electrode fuel cell contactor 621), which will be described later, and a power supply line of one of the positive electrode and the negative electrode are provided on the motor / generator side of the fuel cell contactor, and a current flows from the motor / generator to the fuel cell. A backflow prevention diode (for example, a backflow prevention diode 612, which will be described later), A discharge circuit that connects between the fuel cell contactor and the backflow prevention diode of the power supply line of the power supply line and the fuel cell side from the fuel cell contactor of the power supply line of the other pole (for example, a discharge circuit described later) 65), a discharge resistor (for example, a discharge resistor 654 described later) and a discharge contactor (for example, a discharge contactor 652 described later) provided in the discharge circuit, and at the start of supply of a reaction gas to the fuel cell, the discharge In addition to connecting the contactor, the fuel cell contactor of the one electrode is connected, and generated power consumption means for consuming the generated power of the fuel cell (for example, ECU 80 described later and stack activation processing shown in FIG. 2 described later) Means for execution) And wherein the door.

  According to the present invention, with respect to the positive electrode power supply line and the negative electrode power supply line provided with the positive electrode fuel cell contactor and the negative electrode fuel cell contactor respectively, A discharge circuit for connecting the power supply line of the other pole to the fuel cell side is provided. By connecting the discharge circuit to the positive and negative power supply lines in this way, the closed circuit connecting the fuel cell and the discharge resistor has two contactors, the discharge contactor and the fuel cell contactor of the one electrode. Will be provided. That is, it is possible to make the discharge contactor redundant without providing an extra discharge contactor by using the fuel cell contactor of the one electrode. Thereby, for example, even when the discharge contactor is on-failed, the fuel cell and the discharge resistor can be shut off by turning off the fuel cell contactor of the one electrode. In addition, when the discharge contactor is made redundant, the use of the fuel cell contactor of the one electrode described above can suppress the increase in cost while improving the safety of the fuel cell vehicle.

  According to a second aspect of the present invention, in the fuel cell vehicle according to the first aspect, the fuel cell vehicle has a failure that turns off the fuel cell contactor of the one pole when the discharge contactor has failed. It further includes time shut-off means (for example, an ECU 80 described later and a means related to execution of step S24 of a failure determination process shown in FIG. 3 described later).

  According to the present invention, when the discharge contactor fails to turn on, the fuel cell contactor of the one electrode is turned off to cut off the fuel cell and the discharge resistor. As a result, it is possible to prevent the discharge resistor from being damaged or the power generated by the fuel cell from being consumed more than necessary by the discharge resistor.

  According to a third aspect of the present invention, in the fuel cell vehicle according to the second aspect, the fuel cell vehicle is configured such that the motor / generator side and the other side of the power supply line of the one pole from the backflow prevention diode. A power storage device (for example, a battery 40 to be described later) connected to the motor / generator side from the fuel cell contactor of the power supply line of the first electrode, and the fuel cell contactor of the first electrode by the failure interruption means A failure-time driving means for driving the motor / generator with the electric power of the power storage device after being turned off (for example, an ECU 80 described later and a means related to execution of step S25 of the failure determination processing shown in FIG. 3 described later); Is further provided.

  According to the present invention, when the discharge contactor is turned on and the one fuel cell contactor is turned off, the motor / generator is driven by the electric power of the power storage device connected to the motor / generator side from the fuel cell contactor. . As a result, even when the discharge contactor is on-failed, it is possible to continue traveling while protecting the discharge resistance.

  In order to achieve the above object, a fourth aspect of the present invention is directed to a fuel cell (for example, a fuel cell stack 10 described later) that generates power using a reactive gas, and a motor generator (for example, a motor described later) connected to the fuel cell. A fuel cell vehicle (for example, a fuel cell vehicle 1A described later) that travels by driving the motor / generator with the power generated by the fuel cell. The fuel cell vehicle has a positive fuel cell contactor (for example, described later) provided on a positive power supply line (for example, positive power supply line 61 to be described later) connecting the positive electrode of the fuel cell and the positive electrode of the motor / generator. A negative electrode fuel cell contactor (for example, a negative electrode power supply line 62 to be described later) connected to a negative electrode of the fuel cell and a negative electrode of the motor / generator. A negative electrode fuel cell contactor 621), which will be described later, and a power supply line of one of the positive electrode and the negative electrode are provided on the motor / generator side of the fuel cell contactor, and a current flows from the motor / generator to the fuel cell. A backflow prevention diode (for example, a backflow prevention diode 612, which will be described later), A discharge circuit (for example, a discharge circuit 65A described later) that connects the fuel cell contactor to the fuel cell side and the other pole power supply line to the motor / generator side of the other power supply line. ), A discharge resistor (for example, a discharge resistor 654A described later) and a discharge contactor (for example, a discharge contactor 652A described later) provided in the discharge circuit, and when the supply of the reaction gas to the fuel cell is started, the discharge contactor Is connected to the fuel electrode contactor of the other electrode, and the generated power consumption means for consuming the generated power of the fuel cell (for example, the ECU 80A described later, and the stack startup process shown in FIG. 6) Means) It is characterized in.

  According to a fifth aspect of the present invention, in the fuel cell vehicle according to the fourth aspect, the fuel cell vehicle has a failure that turns off the fuel cell contactor of the other electrode when the discharge contactor is turned on. It further includes time shut-off means (for example, ECU 80A described later, and means for executing step S54 of failure determination processing shown in FIG. 7 described later).

  According to a sixth aspect of the present invention, in the fuel cell vehicle according to the fifth aspect, the fuel cell vehicle is configured such that the motor / generator side and the other side of the backflow prevention diode are included in the power supply line of the one pole. A power storage device (for example, a battery 40 to be described later) connected from the fuel cell contactor to the motor / generator side of the power supply line of the other electrode, and the fuel cell contactor of the other electrode by the failure interruption means A failure-time driving means for driving the motor / generator with the electric power of the power storage device after being turned off (for example, an ECU 80A described later and a means for executing step S55 of the failure determination process shown in FIG. 7 described later); Is further provided.

  The present invention is the invention according to any one of claims 1 to 3 in which the connection mode of the discharge circuit to the positive power supply line and the negative power supply line is changed. Therefore, according to this invention, there exists an effect similar to invention of the said Claims 1-3.

1 is a block diagram showing a configuration of a fuel cell vehicle according to a first embodiment of the present invention. It is a flowchart which shows the procedure of the starting process of the stack | stuck which concerns on the said embodiment. It is a flowchart which shows the procedure which determines the failure of the discharge circuit which concerns on the said embodiment, and a discharge contactor. It is a time chart which shows the specific example of the starting process of the stack | stuck which concerns on the said embodiment. It is a block diagram which shows the structure of the fuel cell vehicle which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the procedure of the starting process of the stack | stuck which concerns on the said embodiment. It is a flowchart which shows the procedure which determines the failure of the discharge circuit which concerns on the said embodiment, and a discharge contactor. It is a time chart which shows the specific example of the starting process of the stack | stuck which concerns on the said embodiment.

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a fuel cell vehicle 1 according to the present embodiment.
The fuel cell vehicle 1 includes a fuel cell stack 10, a motor / generator 20, a reaction gas supply device 30, a battery 40, and an electronic control unit (hereinafter referred to as “ECU (Electric Control Unit)”) 80. Consists of.

  The fuel cell stack (hereinafter referred to as “stack”) 10 has, for example, a stack structure in which several tens to several hundreds of fuel cells are stacked, and is connected to the motor / generator 20 via the stack connection circuit 60. ing. Each fuel cell is configured by sandwiching a membrane electrode structure (MEA) between a pair of separators. The membrane electrode structure is composed of two electrodes, an anode electrode (cathode) and a cathode electrode (anode), and a solid polymer electrolyte membrane sandwiched between these electrodes. Usually, both electrodes are formed of a catalyst layer that performs an oxidation / reduction reaction in contact with the solid polymer electrolyte membrane and a gas diffusion layer in contact with the catalyst layer. The stack 10 generates power by an electrochemical reaction when hydrogen gas is supplied to the anode electrode side and air containing oxygen is supplied to the cathode electrode side.

  The reactive gas supply device 30 includes a hydrogen tank 31 and an air compressor 32, and supplies hydrogen gas stored in the hydrogen tank 31 and air compressed by the air compressor 32 to the stack 10. The supply amount of hydrogen gas and air supplied from the reaction gas supply device 30 to the stack 10 is controlled based on a control signal input from the ECU 80.

  The motor / generator 20 is connected to the stack 10 and the battery 40 via a power drive unit (hereinafter referred to as “PDU (Power Drive Unit)”) 25. The PDU 25 converts the generated power of the stack 10 and the DC power of the battery 40 into three-phase AC power and supplies it to the motor / generator 20 to drive it. The driving force generated by the motor / generator 20 by supplying electric power is transmitted to driving wheels (not shown) via a transmission, and the fuel cell vehicle 1 is caused to travel.

  When the driving force is transmitted from the driving wheels to the motor / generator 20 during deceleration of the fuel cell vehicle 1, the motor / generator 20 functions as a generator and generates a regenerative braking force. The PDU 25 converts the three-phase AC power generated during the regenerative operation of the motor / generator 20 into DC power and supplies it to the battery 40 to charge it.

  The stack connection circuit 60 connects the positive electrode terminal of the stack 10 to the positive electrode terminal of the PDU 25 and the motor / generator 20, and the negative electrode terminal of the stack 10 and the negative electrode terminal of the PDU 25 and the motor / generator 20 to the negative electrode. And a power supply line 62. The positive power supply line 61 is provided with a positive fuel cell contactor 611 and a backflow prevention diode 612, and the negative power supply line 62 is provided with a negative fuel cell contactor 621.

  Each of the positive electrode fuel cell contactor 611 and the negative electrode fuel cell contactor 621 is an electromagnetic switch having a mechanical contact and a drive coil for opening and closing the contact. These fuel cell contactors 611 and 621 operate based on a control signal from the ECU 80 to connect or disconnect the stack 10 and the motor / generator 20. When the motor / generator 20 is driven by the power generated by the stack 10, both the fuel cell contactors 611 and 621 are turned on to connect the stack 10 and the motor / generator 20.

  The backflow prevention diode 612 is provided on the motor generator 20 side of the positive power supply line 61 from the positive fuel cell contactor 611, and prevents a current from flowing back from the battery 40 and the motor generator 20 side to the stack 10.

  Further, a discharge circuit 65 including a discharge resistor 654 for discharging the power of the stack 10 is connected to the power supply lines 61 and 62. The discharge circuit 65 connects between the positive electrode fuel cell contactor 611 and the backflow prevention diode 612 in the positive electrode power supply line 61 and the stack 10 side from the negative electrode fuel cell contactor 621 in the negative electrode power supply line 62.

  The discharge circuit 65 is configured by connecting a current fuse 651, a temperature fuse 653, a discharge resistor 654, and a discharge contactor 652 in series. More specifically, in the discharge circuit 65, a temperature fuse 653 and a current fuse 651 are provided on the positive power supply line 61 side from the discharge resistor 654, and a discharge contactor is provided on the negative power supply line 62 side from the discharge resistor 654. 652 is provided.

  The discharge resistor 654 is connected to the stack 10 and consumes the electric power generated by the stack 10 as Joule heat. The discharge contactor 652 is an electromagnetic switch including a mechanical contact and a drive coil that opens and closes the contact. The discharge contactor 652 operates based on a control signal from the ECU 80 and connects or disconnects the discharge circuit 65.

When the stack 10 and the discharge resistor 654 are connected to discharge the stack 10, the discharge contactor 652 is turned on and the positive fuel cell contactor 611 is turned on.
On the other hand, when the stack 10 and the discharge resistor 654 are cut off, both the discharge contactor 652 and the positive electrode fuel cell contactor 611 are turned off, or either the discharge contactor 652 and the positive electrode fuel cell contactor 611 are turned off. .

  The current fuse 651 and the temperature fuse 653 are fuses that protect circuit elements of the discharge circuit 65. The current fuse 651 disconnects the discharge circuit 65 when a current exceeding a predetermined rated current continues to flow, and prevents an overcurrent from continuing to flow through the discharge resistor 654 and the discharge contactor 652. The thermal fuse 653 is provided in contact with the discharge resistor 654 and is maintained at a temperature substantially equal to the discharge resistor 654. The thermal fuse 653 disconnects the discharge circuit 65 when a state exceeding a predetermined rated temperature continues, and prevents the discharge resistor 654 from overheating.

  The battery 40 stores regenerative electric power during braking of the vehicle and electric power generated by the stack 10 and outputs DC power. The battery 40 is connected to the motor / generator 20 via a relay circuit 70. More specifically, the positive terminal of the battery 40 is connected to the motor generator 20 side from the backflow prevention diode 612 in the positive power supply line 61, and the negative terminal of the battery 40 is connected to the negative fuel in the negative power supply line 62. The battery contactor 621 is connected to the motor / generator 20 side.

  The relay circuit 70 connects or disconnects the positive battery contactor 71 and the precharge contactor 73 that connect or disconnect the positive terminal of the battery 40 and the positive input terminal of the PDU 25, and the negative terminal of the battery 40 and the negative input terminal of the PDU 25. A negative battery contactor 72 and a resistor 74 connected in series to the precharge contactor 73 are provided. Further, the precharge contactor 73 and the resistor 74 are provided in parallel with the positive battery contactor 71 so as to bypass the positive battery contactor 71.

  The battery contactors 71 and 72 and the precharge contactor 73 are electromagnetic switches each having a mechanical contact and a drive coil for opening and closing the contact. These contactors 71, 72, 73 operate based on a control signal from the ECU 80, and connect or disconnect the battery 40 and the PDU 25.

  When precharging to charge a smoothing capacitor included in the motor / generator 20 and its PDU 25 and various auxiliary machines, the precharge contactor 73 connected in series with the resistor 74 is turned on. Then, after this precharge is completed, the positive battery contactor 71 is turned on. When the battery 40 is shut off, all the contactors 71, 72, 73 are turned off.

  Various sensors such as a first current sensor 622, a second current sensor 655, and a thermistor 656, and an ignition switch (not shown) are connected to the ECU 80.

The first current sensor 622 is provided on the stack 10 side of the negative power supply line 62 to which the negative discharge contactor 652 is connected, and detects the output current I _FC of the stack 10 that flows through the negative power supply line 62. A detection signal approximately proportional to the detection value is output to the ECU 80. The second current sensor 655 is provided between the temperature fuse 653 and the current fuse 651 in the discharge circuit 65, and the current flowing through the discharge resistor 654 (hereinafter referred to as “discharge”) while the stack 10 is being discharged. detecting a current _{"hereinafter) I DS,} and outputs a detection signal substantially proportional to the detected value to the ECU 80.

The thermistor 656 is provided in contact with the discharge resistor 654, with is kept substantially equal to the temperature and discharge resistor 654, and outputs a signal substantially proportional to the temperature _{T DS} of the discharge resistor 654 to the ECU 80. The ignition switch is provided in the driver's seat of the fuel cell vehicle 1 and outputs to the ECU 80 a signal for commanding the start or stop of the vehicle according to the operation of the driver.

  The ECU 80 shapes input signal waveforms from various sensors, corrects a voltage level to a predetermined level, converts an analog signal value into a digital signal value, and a central processing unit (hereinafter referred to as “a processing unit”). CPU ”). In addition, the ECU 80 includes a storage circuit that stores various calculation programs executed by the CPU, calculation results, and the like, a reaction gas supply device 30, fuel cell contactors 611 and 621, a discharge contactor 652, battery contactors 71 and 72, and a precharger. And an output circuit that outputs control signals to the charge contactor 73 and the like to control them. Further, with the hardware configuration described above, the ECU 80 has various modules for executing stack activation processing (see FIG. 2 described later), failure determination processing (see FIG. 3 described later), and the like as described below. Composed.

Next, a procedure for stack activation processing and failure determination processing according to the present embodiment will be described in detail with reference to FIGS.
FIG. 2 is a flowchart showing a procedure of stack activation processing. This activation process is executed by the ECU 80 in response to the ignition switch being turned on. At the time of starting this starting process, the positive electrode fuel cell contactor, the negative electrode fuel cell contactor, the discharge contactor, the positive electrode battery contactor, the negative electrode battery contactor, and the precharge contactor are all turned off, and the discharge contactor failure flag described later and The discharge circuit failure flag is set to “0”.

In step S1, it is determined whether or not the stack needs to be discharged. If this determination is YES, the process proceeds to step S2, and if NO, the process proceeds to step S4. More specifically, the soak time from when the ignition switch was turned off last time to stop power generation by the stack until the ignition switch was turned on this time to start the stack was measured, and this soak time was determined according to a predetermined judgment. If it is shorter than the time, it is determined that there is no need to discharge the stack. When the soak time is equal to or longer than the above-described determination time, it is determined that oxygen has entered the anode electrode side of the stack and the stack needs to be discharged.
In addition, when the ignition switch is turned on, the stack voltage is lower than the predetermined value, or the oxygen concentration detected by the oxygen sensor provided in the stack is higher than the predetermined value. Even when there is a possibility of being exposed to a high potential, it is determined that the stack needs to be discharged.

  In step S2, the discharge contactor is turned on to start stack discharge, and the process proceeds to step S3. In step S3, the positive electrode fuel cell contactor is turned on, and the process proceeds to step S4. Thereby, the stack and the discharge resistor are connected. Therefore, when the reactive gas is supplied to the stack and power generation is started, the generated power of the stack is consumed by the discharge resistor.

  In step S4, the precharge is executed by turning on the negative battery contactor and the precharge contactor while the positive battery contactor is turned off.

  In step S5, as the precharge is completed, the precharge contactor is turned off, and the positive battery contactor and the negative battery contactor are turned on. Here, by turning on the positive and negative battery contactors, a load such as an air compressor or a motor / generator can be driven by the electric power of the battery.

  In step S6, stack activation is started. That is, the driving of the air compressor is started and the supply of the reaction gas to the stack is started, and the process proceeds to step S8.

In step S8, it is determined whether or not stack activation is completed. If this determination is NO, the process proceeds to step S9.
Here, whether or not stack activation has been completed can be determined based on, for example, whether or not the stack output voltage V _FC has become greater than a predetermined activation determination value V _OCV . In addition, for example, the determination can be made based on whether or not a predetermined time has elapsed since the supply of the reactive gas in Step S6 described above.

  In step S9, it is determined whether or not the energization time of the discharge resistor is within a predetermined allowable time, or whether or not the temperature of the discharge resistor is equal to or lower than the allowable temperature. If this determination is YES, the process proceeds to step S8, and if NO, the process proceeds to step S10. These allowable time and allowable temperature are appropriately set according to the rating so that the discharge resistance can be protected.

  In step S10, when it is determined that the energization time or temperature of the discharge resistor has exceeded its allowable range, the discharge contactor is turned off to shut off the discharge circuit, and the process proceeds to step S8.

  On the other hand, if the determination in step S8 is YES, the process proceeds to step S11 to connect the stack and the motor / generator. In step S11, it is determined whether or not the positive electrode fuel cell contactor is on, that is, whether or not the stack has been discharged. If the determination in step S11 is YES and the positive electrode fuel cell contactor is already turned on, the process proceeds to step S12, and after only the negative electrode fuel cell contactor is turned on, the process proceeds to step S14. On the other hand, when the determination in step S11 is NO and the positive electrode fuel cell contactor is off, the process proceeds to step S13, and after both the positive electrode fuel cell contactor and the negative electrode fuel cell contactor are turned on, the process proceeds to step S14.

  In step S14, it is determined whether or not the discharge contactor is on. If the determination in step S14 is NO and the discharge contactor has already been turned off, the startup process is immediately terminated. On the other hand, if the determination in step S14 is YES and the discharge contactor is turned on, the process proceeds to step S15, and after the discharge contactor is turned off, the activation process is terminated.

  FIG. 3 is a flowchart illustrating a procedure for determining failure of the discharge circuit and the discharge contactor. This failure determination process is an interrupt process executed by the ECU 80 at a predetermined cycle after turning on the ignition.

  In step S21, it is determined whether or not the discharge contactor is being commanded to turn on. For example, when the stack activation process shown in FIG. 2 is performed, the discharge contactor is instructed to turn on from the time when step S2 is executed to the time when step S10 or step S15 is executed, that is, while the stack is being discharged. Is done.

If the determination in step S21 is NO and it is not in the middle of commanding the discharge contactor to turn on, the process proceeds to step S22 to determine whether the discharge contactor is on. In step S22, the discharge current I _DS values greater than zero, or to determine whether or not the state in which the temperature T _DS of the discharge resistance increased. If the determination in step S22 is YES, this means that the current is flowing through the discharge resistor even though the discharge contactor should be turned off, so the discharge contactor is in an on-failed state. It moves to step S23. On the other hand, if the determination in step S22 is NO, it is determined that no current flows through the discharge resistor and the discharge contactor is in a normal state, and this process is immediately terminated.

  In step S23, “1” is set to a discharge contactor failure flag indicating that the discharge contactor is in an on failure state, and the process proceeds to step S24. In step S24, when it is determined that the discharge contactor is in an on-failure state, the positive electrode fuel cell contactor is turned off in order to reliably disconnect the discharge resistor and the stack, and the process proceeds to step S25. . In step S25, when the positive-electrode fuel cell contactor is turned off to stop running on the power generated by the stack, battery running for driving the motor / generator with battery power is started, and this process is terminated. .

  On the other hand, if the determination in step S21 is YES and the discharge contactor is being commanded on, the process proceeds to step S26. In step S26, it is determined whether or not power is being generated by supplying the reaction gas to the stack. If the determination in step S26 is yes, the process proceeds to step S27 to determine whether the discharge circuit has failed. On the other hand, if the determination in step S26 is NO, this process is immediately terminated.

In step S27, it is determined whether or not the stack output current I _FC is approximately zero. If the determination in step S27 is YES, it means that no current flows through the discharge resistor even though the discharge contactor is turned on while supplying the reaction gas and generating power in the stack. It is determined that the discharge circuit has failed, and the process proceeds to step S28. In step S28, "1" is set in the discharge circuit failure flag indicating that the discharge circuit has failed, and the process is terminated. Here, as a cause of the failure of the discharge circuit, for example, a failure of a discharge contactor or a discharge resistor, a case where a current fuse or a thermal fuse is cut, and the like can be considered. On the other hand, if the determination in step S27 is NO, it is determined that the discharge circuit is in a normal state, and this process is immediately terminated.

FIG. 4 is a time chart showing a specific example of stack activation processing.
First, at time t _0, in response to the ignition switch is turned on to start the boot process of the stack.
At time t _1, in response to the discharge of the stack is determined to be necessary, to turn on the discharge contactor and cathode fuel cell contactor (see steps S2, S3 in FIG. 2).

At time t _2, the turn on the negative battery contactor and the precharge contactor, the motor-generator and its PDU, and starts precharging of smoothing capacitors included in the various auxiliary machines (see step S4 in FIG. 2). Incidentally, the precharge is executed from time _{t 2} to time _{t 3.} Here, as shown in FIG. 4, by initiating a precharge, a period from time t ₂ to time t _3, the output voltage V2 of the battery rises and asymptotically converges to a predetermined value.

At time t _3, as well as turning off the precharge contactor in response to the precharge it is completed, to turn on the positive battery contactor (see step S5 in FIG. 2). Thereby, it becomes possible to drive an air compressor, a motor generator, etc. with the electric power of a battery.
At time t _4, to drive the air compressor by the power of the battery starts supplying to the stack of the reaction gas consisting of hydrogen gas and air (see step S6 in FIG. 2). Here, as shown in FIG. 4, when the supply of the reaction gas is started, power generation is started in the stack, and the output voltage V _{FC of the} stack starts to rise. At this time, since the discharge contactor is turned on as described above, a current flows through the discharge resistor and the stack output current I _FC also starts to rise.

At time t _5, the output voltage V _FC stack is greater than a predetermined activation judgment value V _OCV, and in response to it is determined to have become greater than the output voltage V2 of the battery, turning on the anode fuel cell contactor (Fig. 2 step S12). As described above, the threshold value V2 _TH is set to a value slightly smaller than the activation determination value V _OCV . Accordingly, upon turning on the fuel cell contactor at time t _5, it is possible to prevent the overcurrent from flowing.

The fuel cell contactor from turn on at time t _5, after a predetermined lap time, at time t _6, to turn off the discharge contactor (see step S15 in FIG. 2).

Here, in FIG. 5, in the period when the discharge contactor is turned off after time t _{0 to} t ₁ and time t _6, it is determined whether the discharge contactor is on or not by monitoring the temperature of the discharge current and the discharge resistance. (See steps S21 to S25 in FIG. 3). Further, during the period in which the discharge contactor from time t _{4 to} t ₆ is on and the reactive gas is supplied to the stack, the failure of the discharge circuit is determined by monitoring the output current of the stack (FIG. 3). Steps S21 and S26 to S28).

According to this embodiment, there are the following effects.
(1) With respect to the positive electrode power supply line 61 and the negative electrode power supply line 62 provided with the positive electrode fuel cell contactor 611 and the negative electrode fuel cell contactor 621, the motor generator 20 from the positive electrode fuel cell contactor 611 of the positive electrode power supply line 61. A discharge circuit 65 is provided to connect the side of the negative power supply line 62 to the stack 10 side. By connecting the discharge circuit 65 to the positive and negative power supply lines 61 and 62 in this way, a closed circuit connecting the stack 10 and the discharge resistor 654 includes a discharge contactor 652 and a positive fuel cell contactor 611. Two contactors will be provided. That is, by using the positive electrode fuel cell contactor 611, the discharge contactor can be made redundant without newly providing an extra discharge contactor. Accordingly, for example, even when the discharge contactor 652 is turned on, the stack 10 and the discharge resistor 654 can be shut off by turning off the positive electrode fuel cell contactor 611. In addition, when the discharge contactor is made redundant, by using the positive electrode fuel cell contactor 611, it is possible to suppress the increase in cost while improving the safety of the fuel cell vehicle 1.

  (2) When the discharge contactor 652 fails to turn on, the positive electrode fuel cell contactor 611 is turned off, and the stack 10 and the discharge resistor 654 are shut off. Thereby, it is possible to prevent the discharge resistor 654 from being damaged or the generated power of the stack 10 from being consumed more than necessary by the discharge resistor 654.

  (3) When the discharge contactor 652 is turned on and the positive fuel cell contactor 611 is turned off, the motor / generator 20 is driven by the electric power of the battery 40 connected to the motor / generator 20 side from the fuel cell contactors 611, 621. . As a result, even when the discharge contactor 652 is turned on, the vehicle can continue to travel while protecting the discharge resistor 654.

Second Embodiment
A second embodiment of the present invention will be described with reference to FIGS.
In the following description of the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  FIG. 5 is a block diagram showing the configuration of the fuel cell vehicle 1A according to the present embodiment. The fuel cell vehicle 1A of the present embodiment is different from the fuel cell vehicle 1 of the first embodiment in the configuration of the discharge circuit 65A and the ECU 80A.

  The discharge circuit 65A connects the positive power supply line 61 to the stack 10 side from the positive fuel cell contactor 611 and the negative power supply line 62 to the motor generator 20 side from the negative fuel cell contactor 621.

  The discharge circuit 65A is configured by connecting a temperature fuse 653A, a discharge resistor 654A, a discharge contactor 652A, and a current fuse 651A in series. More specifically, in the discharge circuit 65A, a discharge contactor 652A and a current fuse 651A are provided on the positive electrode power supply line 61 side from the discharge resistor 654A, and a temperature fuse is provided on the negative electrode power supply line 62 side from the discharge resistor 654A. 653A is provided.

When the stack 10 is connected to the discharge resistor 654A and the stack 10 is discharged, the discharge contactor 652A is turned on and the negative fuel cell contactor 621 is turned on.
On the other hand, when the stack 10 and the discharge resistor 654A are cut off, both the discharge contactor 652A and the negative electrode fuel cell contactor 621 are turned off, or either the discharge contactor 652A and the negative electrode fuel cell contactor 621 are turned off. .

Next, a procedure for stack activation processing and failure determination processing according to the present embodiment will be described in detail with reference to FIGS.
FIG. 6 is a flowchart illustrating a procedure of stack activation processing. Among the activation processes of the present embodiment configured by steps S31 to S45, steps S31, S34 to S40, S44, and S45 are respectively steps S1, S4 to S10 of the activation process of the first embodiment shown in FIG. Since it is almost the same as S14 and S15, detailed description is omitted.

  In step S32, the discharge contactor is turned on to start stack discharge, and the process proceeds to step S33. In step S33, the negative electrode fuel cell contactor is turned on, and the process proceeds to step S34. As a result, the stack and the discharge resistor are connected. Therefore, when the reactive gas is supplied to the stack and power generation is started, the generated power of the stack is consumed by the discharge resistor.

  In step S41, it is determined whether or not the negative electrode fuel cell contactor is on, that is, whether or not the stack has been discharged. If the determination in step S41 is YES and the negative electrode fuel cell contactor is already turned on, the process proceeds to step S42, and after only the positive electrode fuel cell contactor is turned on, the process proceeds to step S44. On the other hand, if the determination in step S41 is NO and the negative electrode fuel cell contactor is off, the process proceeds to step S43, and after both the positive electrode fuel cell contactor and the negative electrode fuel cell contactor are turned on, the process proceeds to step S44.

  FIG. 7 is a flowchart showing a procedure for determining failure of the discharge circuit and the discharge contactor. Of the failure determination processing of the present embodiment configured in steps S51 to S58, steps S51, S52, and S56 to S58 are steps S21, S22, and S58, respectively, of the failure determination processing of the first embodiment shown in FIG. And since it is almost the same as S26-S28, detailed description is abbreviate | omitted.

  After setting the discharge contactor failure flag to “1” in step S53, in step S54, the connection between the discharge resistor and the stack is reliably disconnected in response to the determination that the discharge contactor is in an on failure state. Therefore, the negative electrode fuel cell contactor is turned off, and the process proceeds to step S55. In step S55, when the negative electrode fuel cell contactor is turned off to stop running on the power generated by the stack, battery running for driving the motor / generator with battery power is started, and this process is terminated. .

FIG. 8 is a time chart showing a specific example of stack activation processing.
First, at time t _10, in response to the ignition switch is turned on to start the boot process of the stack.
At time t _11, in response to the discharge of the stack is determined to be necessary, discharge contactor and the negative fuel cell contactor is turned on (see Step S32, S33 in FIG. 6).

At time t _12, to turn on the negative battery contactor and the precharge contactor, the motor-generator and its PDU, and starts precharging of smoothing capacitors included in the various auxiliary machines (see step S34 in FIG. 6). Incidentally, the precharge is executed from time _{t 12} to time _{t 13.}

At time t _13, as well as turning off the precharge contactor in response to the precharge it is completed, to turn on the positive battery contactor (see step S35 in FIG. 6).
At time t _14, to drive the air compressor starts supply to the stack of the reaction gas consisting of hydrogen gas and air (see step S36 in FIG. 6).

At time t _15, the output voltage V _FC stack is greater than a predetermined activation judgment value V _OCV, and in response to it is determined to have become greater than the output voltage V2 of the battery, turning on the positive electrode fuel cell contactor (Fig. 6 step S42).
The fuel cell contactor from turn on at time t _15, after a predetermined lap time, at time t _16, to turn off the discharge contactor (see step S45 in FIG. 6).

  According to this embodiment, there exists an effect similar to the above-mentioned (1)-(3).

The present invention is not limited to the embodiment described above, and various modifications can be made.
For example, in the first embodiment, the backflow prevention diode is provided in the positive power supply line. However, the present invention is not limited thereto, and the backflow prevention diode may be provided in the negative power supply line. In this case, it is preferable that the discharge circuit connects between the negative electrode fuel cell contactor and the backflow prevention diode in the negative power supply line and the stack side from the positive fuel cell contactor in the positive power supply line. In this case, the closed circuit connecting the stack and the discharge resistor is provided with a discharge contactor and a negative electrode fuel cell contactor.

  Also, for example, in the second embodiment, the backflow prevention diode is provided on the positive power supply line. However, the present invention is not limited thereto, and the backflow prevention diode may be provided on the negative power supply line. In this case, it is preferable that the discharge circuit connects the negative electrode power supply line to the stack side from the negative electrode fuel cell contactor and the positive electrode power supply line to the motor generator side from the positive electrode fuel cell contactor. In this case, the closed circuit connecting the stack and the discharge resistor is provided with a discharge contactor and a positive electrode fuel cell contactor.

DESCRIPTION OF SYMBOLS 1,1A ... Fuel cell vehicle 10 ... Fuel cell stack (fuel cell)
20 ... motor generator 25 ... PDU
30 ... Reaction gas supply device 40 ... Battery (power storage device)
DESCRIPTION OF SYMBOLS 60 ... Stack connection circuit 61 ... Positive electrode power supply line 611 ... Positive electrode fuel cell contactor 612 ... Backflow prevention diode 62 ... Negative electrode power supply line 621 ... Negative electrode fuel cell contactor 65, 65A ... Discharge circuit 652, 652A ... Discharge contactor 654, 654A ... Discharge resistor 80, 80A ... ECU (generated power consumption means, failure interruption means, failure drive means)

Claims (6)

A fuel cell that generates electricity using reactive gas; and
A fuel cell vehicle that travels by driving the motor / generator with power generated by the fuel cell, the motor / generator connected to the fuel cell,
A positive electrode fuel cell contactor provided on a positive electrode power supply line connecting the positive electrode of the fuel cell and the positive electrode of the motor / generator;
A negative electrode fuel cell contactor provided on a negative electrode power supply line connecting the negative electrode of the fuel cell and the negative electrode of the motor / generator;
Among the power supply lines of either the positive electrode or the negative electrode, the backflow prevention diode is provided on the motor / generator side of the fuel cell contactor and prevents a current from flowing back from the motor / generator to the fuel cell. When,
A discharge circuit that connects between the fuel cell contactor and the backflow prevention diode among the power supply line of the one pole, and a discharge circuit that connects the fuel cell contactor from the fuel cell contactor of the power supply line of the other pole;
A discharge resistor and a discharge contactor provided in the discharge circuit;
When starting to supply reactive gas to the fuel cell, the discharge contactor is connected, and the fuel cell contactor of the one electrode is connected, and generated power consumption means for consuming the generated power of the fuel cell is provided. A fuel cell vehicle.   2. The fuel cell vehicle according to claim 1, further comprising a failure cutoff means for turning off the fuel cell contactor of the one pole when the discharge contactor is on. A power storage device connected to the motor / generator side from the backflow prevention diode of the power supply line of the one pole and from the fuel cell contactor to the motor / generator side of the power supply line of the other pole; ,
3. A failure-time drive means for driving the motor / generator with the electric power of the power storage device after the one-electrode fuel cell contactor is turned off by the failure-time cutoff means. The fuel cell vehicle described in 1. A fuel cell that generates electricity using reactive gas; and
A motor / generator connected to the fuel cell,
A fuel cell vehicle that travels by driving the motor / generator with power generated by the fuel cell,
A positive electrode fuel cell contactor provided on a positive electrode power supply line connecting the positive electrode of the fuel cell and the positive electrode of the motor / generator;
A negative electrode fuel cell contactor provided on a negative electrode power supply line connecting the negative electrode of the fuel cell and the negative electrode of the motor / generator;
Among the power supply lines of either the positive electrode or the negative electrode, the backflow prevention diode is provided on the motor / generator side of the fuel cell contactor and prevents a current from flowing back from the motor / generator to the fuel cell. When,
A discharge circuit for connecting the fuel cell contactor from the fuel cell contactor of the power supply line of the one pole, and a motor / generator side of the power supply line of the other pole from the fuel cell contactor;
A discharge resistor and a discharge contactor provided in the discharge circuit;
When starting supply of the reaction gas to the fuel cell, the discharge contactor is connected, and the fuel electrode contactor of the other electrode is connected, and generated power consumption means for consuming the generated power of the fuel cell is provided. A fuel cell vehicle.   5. The fuel cell vehicle according to claim 4, further comprising a failure interruption means for turning off the fuel cell contactor of the other electrode when the discharge contactor is on. A power storage device connected to the motor / generator side from the backflow prevention diode of the power supply line of the one pole and from the fuel cell contactor to the motor / generator side of the power supply line of the other pole; ,
6. A failure-time driving means for driving the motor / generator with the electric power of the power storage device after turning off the fuel cell contactor of the other electrode by the failure-time cutoff means. The fuel cell vehicle described in 1.

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