JP5061555B2 - Fuel cell system and fuel cell starting method - Google Patents

Description

  The present invention relates to a fuel cell system and a fuel cell system start method, and more particularly to a fuel cell system including a start of a system including peripheral devices existing together with the fuel cell and a fuel cell system start method.

  Since there is little impact on the environment, fuel cells are installed in vehicles. In the fuel cell, for example, a fuel gas such as hydrogen is supplied to the anode side of the fuel cell stack, an oxidizing gas containing oxygen such as air is supplied to the cathode side, and necessary electric power is taken out by a cell chemical reaction through the electrolyte membrane. Further, the fuel cell generates heat due to this battery chemical reaction. Therefore, a compressor, a pump, a pump for cooling water, etc. are used as a peripheral device for the fuel cell to supply fuel gas and oxidizing gas. In addition to the fuel cell, a high-voltage secondary battery, a low-voltage power source that supplies power to electronic devices, and the like are used as the power source for the vehicle. Including these, one fuel cell system is configured, and in order to start the fuel cell system, it is necessary to check the state of these elements.

  For example, in Patent Document 1, when starting a vehicle-mounted power supply system including a secondary battery and a fuel cell, when the maximum power required by the load and the auxiliary machine cannot be supplied by the fuel cell and the secondary battery, warm-up is performed. It is disclosed that the maximum supply power can be supplied. Here, when the maximum power cannot be supplied by the fuel cell, it is determined whether or not it is necessary to warm up by charging the secondary battery based on the temperature of the secondary battery, and the secondary battery is based on the SOC of the secondary battery. It is determined whether the battery is discharged or charged. Based on these judgments, the operation of charging the auxiliary power and the secondary battery with the generated power of the fuel cell and the operation of discharging the secondary battery and supplying the power from the fuel cell and the secondary battery to the auxiliary device are repeated. It is stated that the warm-up time is short.

JP 2004-281219 A

  As described above, Patent Document 1 describes that in a fuel cell system, in order to efficiently supply power to a load and an auxiliary machine, the warm-up time is shortened. However, in order to start the fuel cell system, in addition to the contents described in Patent Document 1, it is necessary to check whether the state of each peripheral device of the fuel cell is sufficient for starting the system. The fuel cell system start command is issued only after this confirmation. Reducing the time required for checking the state of each peripheral device of the fuel cell is advantageous because it enables early start-up of the fuel cell system.

  An object of the present invention is to provide a fuel cell system and a fuel cell system starting method capable of shortening the time until starting.

A fuel cell system according to the present invention includes a fuel cell connected in parallel to a secondary battery via a voltage converter, a system main relay for a secondary battery provided between the secondary battery and the voltage converter, A secondary battery-side smoothing capacitor connected between the secondary battery and the voltage converter; an auxiliary device for a fuel cell connected between the secondary battery and the voltage converter; a voltage converter and a fuel cell; And a controller for controlling the start of the fuel cell, and the controller operates the secondary battery system main relay to supply current to the secondary battery side smoothing capacitor. flow, means for performing a pre-charge of the secondary battery side, after the precharge of the secondary battery side, and means for activating the fuel cell by using the auxiliary connected fuel cell to the secondary battery side, the fuel In parallel with the start-up of battery auxiliary equipment, fuel power is supplied via a voltage converter. Means for performing precharge on the pond side .

Further, in the fuel cell system according to the present invention, the fuel cell system has current detection means for detecting a current flowing through the secondary battery side smoothing capacitor, and the control unit connects the welding detection relay in the secondary battery system main relay. A welding determination means for performing welding determination based on detection data of the current detection means when the welding detection relay is connected, and a current is passed through the secondary battery side smoothing capacitor based on the result of the welding determination means, And a means for performing precharge on the secondary battery side .

Further, in the fuel cell system according to the present invention, a low voltage battery to which an electrical device is connected,
A voltage detection means for detecting the voltage of the low-voltage battery, and the control unit makes a determination necessary for determining a predetermined predetermined determination voltage prior to welding determination at the start of the fuel cell system It is preferable to include a low voltage battery determination unit that sets a time and determines that the state of the low voltage battery is normal when the detection value of the voltage detection unit is equal to or higher than a predetermined determination voltage by the determination time .

The fuel cell system start method according to the present invention includes a secondary battery, a voltage converter, and a fuel cell connected in parallel, and a secondary battery system main between the secondary battery and the voltage converter. A relay is provided , a secondary battery side smoothing capacitor is connected between the secondary battery and the voltage converter, an auxiliary device for the fuel cell is connected between the secondary battery and the voltage converter, the voltage converter and the fuel A starting method of a fuel cell system configured by providing a fuel cell relay between a secondary battery and a secondary battery side smoothing capacitor by operating a secondary battery system main relay to cause a secondary battery to operate. In parallel with the step of performing the precharge on the side, the step of starting the fuel cell using the auxiliary device for the fuel cell connected to the secondary battery side, and the starting of the auxiliary device for the fuel cell, And performing a precharge on the fuel cell side It is characterized by.

  With at least one of the above-described configurations, the fuel cell system includes a fuel cell connected in parallel to the secondary battery via a voltage converter, and a fuel cell auxiliary device connected between the secondary battery and the voltage converter. The That is, a fuel cell auxiliary machine is connected to the secondary battery side. In the prior art, since a fuel cell auxiliary device is connected to the fuel cell side, the auxiliary operation for the fuel cell is not performed until the secondary battery side is precharged and then the fuel cell side precharge is performed. The machine can be driven. According to the above configuration, the fuel cell auxiliary machine can be started when the secondary battery is precharged, and a fuel cell start command can be issued at that time, thereby shortening the start time of the fuel cell system. it can.

  In addition, the fuel cell system performs welding determination based on data of current flowing through the secondary battery side smoothing capacitor when the welding detection relay is connected. In the prior art, welding determination is performed based on the rising data of the charging voltage of the secondary battery-side smoothing capacitor when the welding detection relay is connected. Since the charging voltage of the capacitor rises due to the charging current, the change in the charging current can be detected in a shorter time than the detection of the rising of the charging voltage. Thus, since the welding determination can be performed in a short time, the confirmation time for starting the fuel cell system can be shortened.

  The fuel cell system detects the voltage of the low voltage battery and determines that the state of the low voltage battery is normal when the voltage is equal to or higher than a predetermined determination voltage. In the prior art, a uniform time is taken for the determination of the state of the low voltage battery. Here, if the voltage is equal to or higher than the predetermined determination voltage, it is determined as normal and the process proceeds to the next, so that the confirmation time for starting the fuel cell system can be shortened.

  In addition, a starting method of a fuel cell system configured by connecting a fuel cell auxiliary machine between a secondary battery and a voltage converter operates a secondary battery system main relay to operate the secondary battery side. Precharge is performed, and the fuel cell is started using the auxiliary device for the fuel cell connected to the secondary battery side. In the prior art, since the fuel cell auxiliary device is connected to the fuel cell side, after the secondary battery side precharge, the fuel cell side precharge is executed, and then the fuel cell is started. Thus, since the fuel cell can be started without waiting for the precharge of the fuel cell, the start-up time of the fuel cell system can be shortened.

  Hereinafter, an embodiment according to the present invention will be described in detail with reference to the drawings. In the following description, as a configuration of the fuel cell system, a bidirectional voltage converter is provided between the fuel cell stack and the secondary battery pack. It is good also as a structure which is provided between the secondary battery packs and supplies electric power to the load from the power distributor. In the following description, in addition to these, a 12 VDC / DC converter, a 12 V battery, a system main relay, a fuel cell relay, and the like will be described as being included in the components of the fuel cell system. However, a system in which some of these elements are omitted. But you can. Moreover, the system which added the element other than this may be sufficient.

  FIG. 1 is a configuration diagram of a fuel cell system 10. The fuel cell system 10 includes a secondary battery 12, a system main relay 20, a 12 VDC / DC converter 22, a secondary battery side smoothing capacitor 30, and a current sensor 32 that detects a current of the secondary battery side smoothing capacitor 30. The voltage converter 36 capable of bidirectional operation, the fuel cell-side smoothing capacitor 40, the fuel cell relay 38, and the fuel cell 42 are configured. Further, the output of the 12 VDC / DC converter 22 is connected to a 12 V battery 24, and a voltage sensor 28 is connected to the 12 V battery 24.

The 12V battery 24 is connected to a low voltage load 26 that is driven at a low voltage. A fuel cell auxiliary machine 34 is connected between the positive electrode bus and the negative electrode bus between the secondary battery 12 and the voltage converter 36. Further, the control unit 50 controls the operation of these elements as a whole.
Is provided. Although not a component of the fuel cell system 10 here, an inverter 44 is connected between the positive and negative buses on the fuel cell side, and the inverter 44 is connected to a motor / generator (M / G) for a vehicle. ) 46 is connected.

  The secondary battery 12 is a battery pack in which a plurality of lithium ion cells or a plurality of nickel metal hydride cells are combined to form a high voltage battery of about 200V to 400V.

  The system main relay 20 is a relay for turning on and off the high voltage power line on the secondary battery 12 side. In consideration of relay welding at the time of cutting off the high voltage power, one relay is provided on each of the positive bus side and the negative bus side. Further, another relay having a current limiting resistor connected to either bus is provided. This relay with a current limiting resistor has a function of gradually charging by turning it on, and is used for relay welding determination. The welding determination using the system main relay 20 and the charging procedure will be described later.

  The 12 VDC / DC converter 22 is a voltage converter having a function of adjusting high voltage power to a low voltage of 12 V and supplying the low voltage power to a 12 V battery 24. When the two-way operation is performed, the power from the 12V battery 24 can be returned to the high voltage side in an emergency or the like.

  The 12V battery 24 is composed of a lead storage battery or the like, and is used in a low voltage load 26 such as a microcomputer (microcomputer) that operates at a constant voltage of 12V in a vehicle, various sensors, radio onboard electronic devices, an air conditioner, various small motors, etc. It has a function of supplying power.

  The voltage sensor 28 connected to the 12V battery 24 is a voltmeter having a function of monitoring the voltage state of the 12V battery 24. The detection data of the voltage sensor 28 is transmitted to the control unit 50 and used when starting the fuel cell system 10 as will be described later.

  The secondary battery-side smoothing capacitor 30 is a large-capacity capacitor having a function of absorbing fluctuations such as a voltage between the positive and negative electrode buses on the secondary battery side and suppressing pulsation as DC power.

  The current sensor 32 arranged in series with the secondary battery side smoothing capacitor 30 is an ammeter having a function of detecting a current flowing through the secondary battery side smoothing capacitor 30. The detection data of the current sensor 32 is transmitted to the control unit 50 and used when starting the fuel cell system 10 as will be described later.

  The voltage converter 36 is a bi-directional voltage converter for high voltage having a function of performing voltage conversion between the high voltage power on the secondary battery side and the high voltage power on the fuel cell side to exchange power. It is.

  In the arrangement between the secondary battery 12 and the voltage converter 36, the fuel cell auxiliary device 34 is connected between the positive electrode bus and the negative electrode bus. The fuel cell auxiliary machine is an electric device used when the fuel cell 42 is operated. As auxiliary equipment for fuel cells, an air compressor (ACP) that compresses oxidizing gas and supplies it to the fuel cell stack, a hydrogen pump for feeding hydrogen, which is fuel gas, to the fuel cell stack, cooling for cooling the fuel cell stack, etc. Includes water pumps.

  The fuel cell-side smoothing capacitor 40 is a large-capacity capacitor that has a function of absorbing fluctuations in the voltage between the positive and negative electrode buses on the fuel cell side and suppressing pulsation as DC power.

  The fuel cell relay 38 is a relay for turning on and off the high voltage power line on the fuel cell 42 side. As described in the case of the system main relay 20, one relay is provided on each of the positive bus side and the negative bus side in consideration of relay welding at the time of cutting off the high voltage power.

  The fuel cell 42 is a type of assembled battery configured to be able to take out high-voltage generated power of about 200V to 400V by combining a plurality of fuel cells, and is called a fuel cell stack. Here, each fuel cell supplies hydrogen as a fuel gas to the anode side, supplies air as an oxidizing gas to the cathode side, and takes out necessary power by a battery chemical reaction through an electrolyte membrane that is a solid polymer membrane. It has a function. In order to operate the fuel cell 42, it is necessary to operate the fuel cell auxiliary device.

  As described above, the DC power of the power source constituted by the secondary battery 12 and the fuel cell 42 is converted into three-phase power by the inverter 44, and the motor / generator 46 can be driven. Further, when the vehicle is braked, the regenerative power of the motor / generator 46 can be converted into DC power by the inverter 44, and the secondary battery 12 can be charged with this.

  The control unit 50 has a function of performing operation control of each of the above-described elements, particularly start control. The control unit 50 can be configured with an in-vehicle computer. Although the control part 50 can also be comprised with an independent computer, the function can also be made into the function of another vehicle-mounted computer. For example, in the case of a vehicle having a hybrid CPU, the function of the control unit 50 may be provided to the hybrid CPU.

  The control unit 50 has the following contents as a function of start control. That is, from the starting order, the low voltage battery state determination module 60 that determines the voltage state of the 12V battery 24, the welding determination module 58 that determines whether the system main relay 20 is welded, the secondary battery side smoothing capacitor, etc. A secondary battery side precharge execution module 52 that performs charging, a fuel cell activation module 54 that activates the fuel cell 42 using the fuel cell auxiliary machine 34, and a fuel cell side that charges the fuel cell side smoothing capacitor 40 and the like. A precharge execution module 56 is included. These functions can be realized by software, and specifically by executing a corresponding fuel cell system start program.

  The functions of the fuel cell system 10 having the above-described configuration, particularly the functions related to the start control of the control unit 50 will be described below. In the following, the reference numerals of the elements used in FIG. 1 are used. For easy comparison, FIG. 2 will be used first to explain the start control procedure of the fuel cell system in the prior art, and next, FIG. 3 will be used to explain the start control procedure of the fuel cell system 10 configured as described above. explain. The fuel cell system of the prior art has two differences in the configuration of FIG. One is that the fuel cell auxiliary machine 34 is connected between the positive electrode bus and the negative electrode bus between the voltage converter 36 and the fuel cell 42, and the other is the control unit. The contents of 50 start controls.

  FIG. 2 is a flowchart showing a procedure for starting control of a conventional fuel cell system. In the figure, the time is shown on the horizontal axis so that the time required for each procedure of the start control can be understood.

  When the ignition switch (IG) is turned on in the vehicle, the control unit 50 starts to start the fuel cell system. First, the state of the low-voltage battery is checked to see if the low-voltage load 26 such as a microcomputer, various sensors, and an in-vehicle electronic device can be operated (S10). Specifically, it is checked whether or not the output voltage of the 12V battery 24 is sufficient. For this purpose, the detection data of the voltage sensor 28 is acquired after a certain time from the turning on of the IG, compared with a predetermined value, and if the voltage is lower than that value, a warning signal is output and 12 V is output to the user. Notifies that the battery is not fully charged. The predetermined value can be set to 11.5 V, for example. The fixed time from IG ON can be determined to be about 500 msec, for example.

  When a predetermined time for checking the low-voltage battery state elapses, the system main relay 20 is checked for welding (S12). As described above, the welding determination of the system main relay 20 is performed by turning on the relay connected to the resistance among the three relays of the system main relay 20, and the voltage across the secondary battery side smoothing capacitor 30 at that time increases. It is judged by whether or not. In this case, the other two relays constituting the system main relay 20 remain off. If the relay that remains off is not welded, current does not flow through the secondary battery side smoothing capacitor 30. If this OFF relay is welded, in particular, if a relay provided on a bus different from the bus provided with the relay to which the resistor is connected is welded, current flows through the secondary battery side smoothing capacitor 30; As the battery is charged, the voltage across it increases. This voltage increase is detected by a voltmeter (not shown in FIG. 1), and if a predetermined threshold value is exceeded, it is determined that the system main relay 20 is welded, a warning signal is output, and the system main relay is Inform the welding. Since the system main relay 20 has a function of cutting off the high voltage line, the presence or absence of a voltage increase due to welding is carefully determined, and therefore a considerable time is required for the welding check. For example, it may take as long as the low voltage battery status check.

  When the welding check is completed, precharging is executed next. The pre-charge means that the secondary battery side smoothing capacitor 30 and the fuel cell side smoothing capacitor 40 are gradually charged between the positive electrode bus and the negative electrode bus of the high voltage line, and are raised to the voltage level of the secondary battery 12. It is a preliminary charge. That is, there is no voltage difference between the positive electrode bus and the negative electrode bus of the high voltage line at the start, and there is no charge in the secondary battery side smoothing capacitor 30 and the fuel cell side smoothing capacitor 40. When this secondary battery is connected, an excessive inrush current flows through these smoothing capacitors and the like, and this is prevented by precharging.

  Precharging is performed in two stages. Initially, the secondary battery side precharge is executed (S14). Here, the system main relay 20 is turned on while the fuel cell relay 38 is turned off. Thereby, the secondary battery side smoothing capacitor 30 and the like are charged. The time required for precharging is determined by the capacitance value of the secondary battery side smoothing capacitor 30 which is a large-capacity capacitor, and requires a considerable time. For example, it may take as long as the low voltage battery status check.

  Next, fuel cell side precharge is performed (S16). This is performed via the voltage converter 36 with the main system relay turned on, whereby the fuel cell side smoothing capacitor 40 and the like are charged. The time required for this precharge is also determined by the capacitance value of the fuel cell side smoothing capacitor 40, which is a large capacity capacitor, and requires the same time as the secondary battery side precharge.

  When the fuel cell side precharge is completed, the fuel cell auxiliary machine 34 connected between the positive electrode bus and the negative electrode bus between the voltage converter 36 and the fuel cell 42 can be started. Here, a start command for the fuel cell is issued (S18).

  The start control of the fuel cell system 10 is performed by these steps. In the prior art, it may take about 1 sec to about 2 sec from IG on to fuel cell start command.

  FIG. 3 is a flowchart showing a start control procedure in the fuel cell system 10 having the configuration described in FIG. As in FIG. 2, FIG. 3 is also shown as a time chart for each procedure with time on the horizontal axis so that the time required for each procedure of the start control can be understood. Each procedure shown in FIG. 3 corresponds to each process procedure of the fuel cell system start control program executed by the control unit 50.

  When the ignition switch (IG) is turned on in the vehicle, the control unit 50 starts to start the fuel cell system. First, whether or not the low voltage load 26 such as a microcomputer can be operated is determined by detecting the output voltage of the 12V battery 24 (S20). The process of this step is executed by the function of the low voltage battery state determination module 60 of the control unit 50. In the prior art, the detection value of the voltage sensor 28 is compared with a predetermined value after a predetermined time from IG ON, but here, the detection of the terminal voltage of the 12V battery 24 by the voltage sensor 28 is started from IG ON, and the determination voltage Is determined in advance, and when the determination voltage is reached, it is determined that the state of the low-voltage battery is normal, and this process ends.

  If the detection value of the voltage sensor 28 rises and there is an output of about 10V in a short time, the state of the 12V battery 24 can be determined to be normal. Therefore, if the determination time is set and the determination voltage is reached by the determination time, It can be determined to be normal. The determination time can be about half of the predetermined time of the prior art. For example, when the determination voltage is about 10 V, the determination time can be about 200 msec. Thus, the time for checking the state of the low-voltage battery can be shortened by confirming that the determination voltage is constant rather than waiting for a uniform predetermined time as in the prior art.

  Next, welding determination is performed (S22). The process in this step is executed by the function of the welding determination module 58 of the control unit 50. This will be described with reference to FIGS. 4 and 5. FIG. It is known that the welding determination is performed with the current limiting resistor relay 14 among the three relays 14, 15, 16 of the system main relay 20 turned on and the remaining two relays 15, 16 being turned off. Is the same. In FIG. 4, a relay (CONT1) 14 with a current limiting resistor and a normal relay (CONT2) 15 are provided on the positive bus of the high voltage line, and a normal relay (CONT3) 16 is also provided on the negative bus. At this time, the fuel cell relay 38 remains off. In FIG. 4, the relay (CONT 3) provided on the negative electrode bus of the system main relay 20 is in an ON state, but this indicates that the relay is welded. Only the relay with current limiting resistor (CONT1) 14 is turned on by the command.

  As described above, when the relay of the system main relay 20 is welded for some reason, as shown in FIG. 4, the current 70 flows through the secondary battery side smoothing capacitor 30 and charging is performed. This is shown in FIG. In FIG. 5, the horizontal axis represents time, and the vertical axis represents charging current (I) flowing through the secondary battery side smoothing capacitor 30 and voltage across the secondary battery side smoothing capacitor 30 (V). Is shown. In addition, the ON time of the relay (CONT1) 14 with a current limiting resistor is shown. As shown in FIG. 5, the rising of the charging current (I) is earlier than the rising of the both-end voltage (V). This has the same tendency as the characteristics of current and voltage when a constant voltage is applied to a capacitor, which is generally well known.

  Therefore, if an appropriate threshold value is set for the rise of the charging current (I), and it is determined that welding has occurred in the system main relay 20 when the threshold value is exceeded, the time required for the determination is shown in FIG. T (I) shown. On the other hand, when the welding is judged at the rising edge of the voltage (V) as in the prior art, an appropriate threshold is set for the rising edge of the voltage (V), and when the threshold is exceeded, the system main relay 20 The time required for determining that welding has occurred is t (V) shown in FIG. Based on the difference between the rising characteristic of the charging current (I) and the rising characteristic of the both-end voltage (V), the determination time t (I) based on the charging current (I) is the determination time t (V) based on the both-end voltage (V). Considerably shorter.

  In this way, by performing welding determination based on the detection data of the current flowing through the secondary battery side smoothing capacitor 30, it is possible to make a determination based on the detection data of the voltage across the secondary battery side smoothing capacitor 30 as in the prior art. The time required for welding determination can be shortened. For example, welding determination can be performed in about half the time compared to the prior art.

  As a result of the welding determination, if it is determined that there is welding, a warning signal to that effect is output to notify the user of welding of the system main relay. When it is determined that there is no welding, CONT1 used for welding determination is returned to the original OFF state.

  If it is determined that there is no welding in S22, then secondary battery side precharge is executed (S24). The process in this step is executed by the function of the secondary battery side precharge execution module 52 of the control unit 50. As described with reference to FIG. 2, the secondary battery side precharge is performed when the fuel cell relay 38 is off and the system main relay 20 is turned on. Charging is performed.

  In the secondary battery side precharge, connection control of the three relays of the system main relay 20 described in FIG. 4 is performed according to the following procedure. When the welding determination is finished, all the three relays of the system main relay 20 are in the off state. The secondary battery side precharge is started when CONT1 and CONT3 are simultaneously turned on, or when either one is turned on first and the other is turned on immediately thereafter. This state is different in that CONT3 is turned on by the controller 50 without welding, but in the same state as in FIG. 4, the current 70 is passed through the current limiting resistor of CONT1 to the secondary battery side smoothing capacitor 30 and the like. Flows. The current limiting resistor of CONT1 has a function of suppressing charging so that an excessive inrush current does not flow from the secondary battery 12 to the high voltage line, and gradually charging. When the voltage across the secondary battery side smoothing capacitor 30 has fully increased, CONT2 is turned on and CONT1 is turned off, where the secondary battery side precharge is completed. The time required for the secondary battery side precharge is substantially the same as the time required for the conventional technology.

  When the secondary battery side precharge is completed, the fuel cell auxiliary machine 34 connected between the positive electrode bus and the negative electrode bus can be started between the secondary battery 12 and the voltage converter 36, and therefore, the fuel cell 42. Is enabled, a fuel cell activation command is issued (S26). The process in this step is executed by the function of the fuel cell activation module 54 of the control unit 50. In the prior art, as described above, since the fuel cell auxiliary device 34 is connected between the positive electrode bus and the negative electrode bus between the voltage converter 36 and the fuel cell 42, as described in FIG. The fuel cell start command (S18) is not issued until the next fuel cell side precharge is completed (S16). Therefore, in the fuel cell system 10 of FIG. 1, the time until the fuel cell activation command is issued is at least the time required for the fuel cell side precharge as compared with the prior art. Further, in the low voltage battery state determination (S20) and the welding determination (S22), as described above, the time required for the determination is shorter than that of the conventional technology as compared with the conventional technology. The time required can be considerably shortened.

  When the secondary battery side precharge is completed in S24, the start of the fuel cell auxiliary machine 34 is started as described above, and in parallel therewith, the fuel cell side precharge is performed (S28). The process in this step is executed by the function of the fuel cell side precharge execution module 56 of the control unit 50. As described with reference to FIG. 2, the fuel cell side precharge is performed via the voltage converter 36 with the system main relay 20 turned on, thereby charging the fuel cell side smoothing capacitor 40 and the like. Is done.

  FIG. 6 is a diagram showing how fuel cell side precharging is performed. In the state where the system main relay 20 is turned on, a current 72 flows from the secondary battery 12 through the voltage converter 36, whereby the fuel cell side smoothing capacitor 40 and the like are charged. In this manner, the start control in the fuel cell system 10 is executed in a shortened time compared to the prior art.

1 is a configuration diagram of a fuel cell system in an embodiment according to the present invention. It is a figure explaining the procedure of starting control of the fuel cell system in a prior art. It is a figure explaining the procedure of starting control of the fuel cell system in embodiment which concerns on this invention. It is a figure explaining the mode of welding judgment in an embodiment concerning the present invention. It is a figure which compares and demonstrates the welding determination in embodiment which concerns on this invention, and the welding determination in a prior art. In embodiment which concerns on this invention, it is a figure which shows a mode that fuel cell side precharge is performed.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Fuel cell system, 12 Secondary battery, 14, 15, 16 Relay, 20 System main relay, 22 12VDC / DC converter, 24 12V battery, 26 Low voltage load, 28 Voltage sensor, 30 Secondary battery side smoothing capacitor, 32 Current sensor, 34 Fuel cell auxiliary machine, 36 Voltage converter, 38 Fuel cell relay, 40 Fuel cell side smoothing capacitor, 42 Fuel cell, 44 Inverter, 46 Motor generator, 50 Control unit, 52 Secondary battery side pre Charge execution module, 54 Fuel cell activation module, 56 Fuel cell side precharge execution module, 58 Welding determination module, 60 Low voltage battery state determination module, 70, 72 Current.

Claims (4)

A fuel cell connected in parallel to the secondary battery via a voltage converter;
A secondary battery system main relay provided between the secondary battery and the voltage converter;
A secondary battery side smoothing capacitor connected between the secondary battery and the voltage converter;
A fuel cell auxiliary machine connected between the secondary battery and the voltage converter;
A fuel cell relay provided between the voltage converter and the fuel cell;
A control unit for controlling the start of the fuel cell;
Have
The control unit
Means for operating a secondary battery system main relay to cause a current to flow through the secondary battery side smoothing capacitor and to perform precharge on the secondary battery side;
Means for starting the fuel cell using a fuel cell auxiliary device connected to the secondary battery side after precharging on the secondary battery side;
Means for performing precharge on the fuel cell side via the voltage converter in parallel with the activation of the auxiliary device for the fuel cell;
A fuel cell system comprising: The fuel cell system according to claim 1, wherein
Current detection means for detecting the current flowing in the secondary battery side smoothing capacitor;
The control unit
Means for connecting a welding detection relay in the system main relay for the secondary battery;
Welding determination means for performing welding determination based on the detection data of the current detection means when the welding detection relay is connected;
Means for causing a current to flow through the secondary battery side smoothing capacitor based on the result of the welding determination means, and performing precharge on the secondary battery side;
A fuel cell system comprising: The fuel cell system according to claim 1 or 2,
A low voltage battery to which electrical equipment is connected;
Voltage detection means for detecting the voltage of the low voltage battery;
Have
The control unit
When starting the fuel cell system , prior to welding determination, a determination time required to determine a predetermined determination voltage is set, and the detection value of the voltage detection means is equal to or higher than the predetermined determination voltage by the determination time. And a low voltage battery determining means for determining that the state of the low voltage battery is normal. A secondary battery, a voltage converter, and a fuel cell are connected in parallel, and a system main relay for a secondary battery is provided between the secondary battery and the voltage converter, and between the secondary battery and the voltage converter. The secondary battery side smoothing capacitor is connected to the battery, the fuel cell auxiliary machine is connected between the secondary battery and the voltage converter, and the fuel cell relay is provided between the voltage converter and the fuel cell. A fuel cell system starting method comprising:
Operating the secondary battery system main relay to pass a current through the secondary battery side smoothing capacitor and executing precharge on the secondary battery side;
Starting a fuel cell using an auxiliary device for the fuel cell connected to the secondary battery side;
In parallel with the start of the fuel cell auxiliary machine, a step of performing precharge on the fuel cell side via the voltage converter;
A method for starting a fuel cell system, comprising:

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