JP2007149621A - Fuel cell system and control method at start of its operation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid a drop in voltage and enhance starting ability in a fuel cell system capable of quickly starting the operation of a fuel cell even if an output of a power source for driving an accessory is unstable, and in a control method of the starting of the fuel cell system. <P>SOLUTION: A fuel cell system is equipped with a high voltage power storage device 15; a low voltage power storage device 19 having a voltage lower than that of the high voltage power storage device 15; a low voltage accessory 20 driven mainly by the electric power of the low voltage power storage device 19; and a DC-DC converter 18 interposed between the high voltage power storage device 15 and the low voltage power storage device 19. When the fuel cell system is made to start, a driving mode of the low voltage accessory 20 is varied according to the state of the low voltage power storage device 19 at starting. The driving of at least a part unnecessary for starting the fuel cell system 1 out of the low voltage accessories 20 is preferably stopped, and the accessory necessary for starting the fuel cell system 1 out of the low voltage accessories 20 is preferably started at a staggering time. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel cell system and a control method at the time of startup. More specifically, the present invention relates to an improvement of a control method at the time of starting a fuel cell system.

In order to operate the fuel cell system, it is necessary to drive an auxiliary device such as a valve in the system. In the case of a vehicle system, the power of a 12V auxiliary power supply is often used (see, for example, Patent Document 1). In the case of a home (stationary) system, power from a commercial power source is often used.
JP 2002-110187 A

  If the output of the auxiliary drive power supply is unstable when the fuel cell system is activated as described above, the operation of the auxiliary machine will not be stable even if the auxiliary machine is operated in the same sequence as normal. Startup may not work. However, there is a problem that the start-up of the fuel cell is delayed when the auxiliary machine drive start is waited until the auxiliary machine drive power supply is stabilized.

  Accordingly, an object of the present invention is to provide a fuel cell system capable of quickly starting a fuel cell even when the output of an auxiliary machine driving power source is unstable, and a control method at the time of starting the fuel cell.

  In order to solve such a problem, the present inventor has made various studies and has come to know a technique capable of solving such a problem.

  The present invention is based on such knowledge, and the invention according to claim 1 is a fuel cell system including a fuel cell and a low-voltage low-voltage power source among secondary batteries having different voltages. The low-voltage auxiliary machine driven by the low-voltage power supply is driven or stopped according to the situation of the low-voltage power supply system at the time of startup.

  In this fuel cell system, the driving mode at the time of start-up is changed according to the situation of the low-voltage power supply system that may cause a voltage drop. In other words, if the power (voltage) of the low-voltage power supply is sufficient and there is no risk of a voltage drop even if a predetermined low-voltage auxiliary machine is driven at the same time as starting the system, the low-voltage auxiliary machine is set at the same time as starting the system. Drive it. According to this, it is possible to complete the system start-up earlier than before while avoiding the voltage drop. Further, if some low-voltage auxiliary machines are stopped according to the situation, at least power consumption can be avoided, so that it is possible to start the system while suppressing the voltage drop. . On the other hand, if the situation is such that there is a risk of a voltage drop, it is possible to secure at least the same startup time as in the prior art by starting up in the same manner as in the prior art. As described above, the present invention is characteristic in that the start-up control is performed as necessary while observing the state of the low-voltage power supply system, instead of always performing the start-up in the same sequence. Note that the power source in the present invention includes a power storage device. As an example of the power storage device, a battery (secondary battery) can be cited. However, the present invention is not limited to this, and can be applied to, for example, a nickel hydride battery, a lithium ion battery, or a capacitor.

  According to a second aspect of the present invention, in the fuel cell system according to the first aspect, at least a part of the low-pressure auxiliary machine that is unnecessary for starting the fuel cell system is stopped. . If at least a part of the low-voltage auxiliary machine unnecessary for system startup is stopped, at least power consumption can be suppressed and voltage drop can be suppressed.

  According to a third aspect of the present invention, in the fuel cell system according to the first or second aspect, the low-pressure auxiliary machine that is necessary for starting up the fuel cell system is started at different times. . For example, if there are multiple low-voltage accessories, start them at different times to disperse the inrush current (rush current) and avoid concentrating it to suppress voltage drop in the low-voltage power supply system It becomes possible.

  According to a fourth aspect of the present invention, in the fuel cell system according to the first or second aspect, when the voltage of the low-voltage power source is lower than a predetermined value, the low-voltage power source and the high-voltage having a higher voltage than the low-voltage power source. The low-voltage auxiliary machine is started after the DC / DC converter interposed between the power supply and the power supply is started. In a fuel cell system configured with a high-voltage power supply and a low-voltage power supply, a DC / DC converter interposed between the high-voltage power supply and the low-voltage power supply assists power from the high-voltage side to assist in the low-voltage power supply system. There is also a role of avoiding voltage drop. As in the present invention, when the voltage of the low-voltage power source is lower than the predetermined value, it is possible to avoid a voltage drop by starting the low-voltage auxiliary machine after waiting for the DC / DC converter to start. .

  According to a fifth aspect of the present invention, in the fuel cell system according to the first or second aspect, when at least a part of the low-voltage auxiliary machine does not start, the low-voltage power supply and a voltage higher than the low-voltage power supply The low-voltage auxiliary machine is started after the DC / DC converter interposed between the high-voltage power supply and the high-voltage power supply is started. In this case, there is a risk that a voltage drop has occurred in the low-voltage power supply system. However, if the low-voltage auxiliary machine is started after starting the DC / DC converter in this way, It can be activated in a state where it can receive assistance.

  According to a sixth aspect of the present invention, the low-pressure auxiliary machine in the fuel cell system according to any one of the first to fifth aspects is disposed in a hydrogen gas supply system for supplying hydrogen gas to the fuel cell. It is a hydrogen gas supply valve or a hydrogen gas supply actuator. In the current fuel cell system, it is common that a plurality of high-pressure hydrogen tanks are installed, each of which is provided with a hydrogen supply valve and the like, and thus power consumption at startup is often large. However, the present invention is particularly suitable when applied to such a case.

  The invention described in claim 7 is a high voltage power storage device, a low voltage power storage device having a voltage lower than that of the high voltage power storage device, a low voltage auxiliary machine driven mainly by electric power of the low voltage power storage device, and the high voltage power storage device. In a control method at the time of start-up of a fuel cell system including a DC / DC converter interposed between the low-voltage power storage device and the low-voltage power storage device, a mode of driving the low-voltage auxiliary machine according to the state of the low-voltage power storage device at the time of start It is characterized by changing.

  In this control method, the driving mode at startup is changed according to the situation of the low-voltage power storage device that may cause a voltage drop. In other words, if the voltage (electric power) of the low-voltage power storage device is sufficient, and if a certain low-voltage auxiliary machine is driven at the same time as starting the system, there is no risk of voltage drop. Drive simultaneously. According to this, it is possible to complete the system start-up earlier than before while avoiding the voltage drop. Further, if some low-voltage auxiliary machines are stopped according to the situation, at least power consumption can be avoided, so that it is possible to start the system while suppressing the voltage drop. . On the other hand, if the situation is such that there is a risk of a voltage drop, it is possible to secure at least the same startup time as in the prior art by starting up in the same manner as in the prior art. As described above, the present invention is characteristic in that the start-up control is performed as necessary while observing the state of the low-voltage power storage device (or the low-voltage circuit) instead of always starting in the same sequence.

  According to an eighth aspect of the present invention, in the control method according to the seventh aspect, at least a part of the auxiliary equipment unnecessary for starting up the fuel cell system among the low-pressure auxiliary machines is stopped. is there. If at least a part of the low-voltage auxiliary machine unnecessary for system startup is stopped, at least power consumption can be suppressed and voltage drop can be suppressed.

  The invention according to claim 9 is the control method according to claim 7 or 8, wherein among the low-pressure auxiliary machines, auxiliary machines required for starting the fuel cell system are started at different times. . For example, when there are a plurality of low-voltage auxiliary machines, the inrush currents (rush currents) are dispersed by starting them at different times, thereby avoiding the concentration and suppressing the voltage drop in the low-voltage power storage device. It becomes possible.

  According to a tenth aspect of the present invention, in the control method according to the seventh or eighth aspect, when the voltage of the low-voltage power storage device is lower than a predetermined value, the low-voltage auxiliary machine is activated after the DC / DC converter is activated. Is to start. The DC / DC converter interposed between the high-voltage power storage device and the low-voltage power storage device also has a role of avoiding a voltage drop in the low-voltage power storage device by assisting power from the high-voltage side. As in the present invention, when the voltage of the low-voltage power storage device is lower than the predetermined value, it is possible to avoid a voltage drop by starting the low-voltage auxiliary machine after waiting for the DC / DC converter to start. it can.

  According to an eleventh aspect of the present invention, in the control method according to the seventh aspect, when at least a part of the low-voltage auxiliary machine is not activated, the low-voltage auxiliary machine is activated after the DC / DC converter is activated. It is to start. In this case, there is a risk that a voltage drop has occurred in the low-voltage power storage device, but if the low-voltage auxiliary machine is started after starting the DC / DC converter in this way, It can be activated in a state where it can receive assistance.

  Furthermore, in the invention described in claim 12, the low-pressure auxiliary machine in the control method according to any one of claims 7 to 11 is arranged in a hydrogen gas supply system for supplying hydrogen gas to the fuel cell. This is a hydrogen gas supply valve or a hydrogen gas supply actuator. In the current fuel cell system, it is common that a plurality of high-pressure hydrogen tanks are installed, each of which is provided with a hydrogen supply valve and the like, and thus power consumption at startup is often large. However, the present invention is particularly suitable when applied to such a case.

  According to the present invention, it is possible to quickly start the fuel cell even when the output of the auxiliary machine driving power source is unstable.

  Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings.

  1 to 3 show an embodiment of a fuel cell system according to the present invention. A fuel cell system 1 according to the present invention includes a high voltage power source, a low voltage power source having a voltage lower than that of the high voltage power source, a low voltage auxiliary machine driven mainly by the power of the low voltage power source, and the high voltage power source and the low voltage power source. It has a configuration including an interposed DC / DC converter. In the present embodiment, control is performed to change the driving mode of the low-pressure auxiliary machine in accordance with the state of the low-voltage power supply at the time of starting the fuel cell system. In the following, first, the outline of the fuel cell system 1 will be described, and then the contents of the control method when the fuel cell system 1 is started will be described (see FIGS. 1 to 3).

  The high-voltage power supply (and low-voltage power supply) of the fuel cell system 1 includes a power storage device. In the embodiment described below, a case where the high-voltage power source is a high-voltage power storage device and the low-voltage power source is a low-voltage power storage device will be described as an example. As an example of the power storage device in this specification, a battery (secondary battery) can be given. However, the present invention is not limited to this, and can be applied to, for example, a nickel metal hydride battery, a lithium ion battery, or a capacitor. is there.

  FIG. 1 shows a schematic configuration of a fuel cell system 1 according to the present embodiment. The fuel cell system 1 shown in the present embodiment can be used as, for example, an in-vehicle power generation system of a fuel cell vehicle (FCHV; Fuel Cell Hybrid Vehicle), but is not limited to this, and various mobile objects (for example, ships) Naturally, it can also be used as a power generation system mounted on a self-propelled device such as a robot or a robot. A fuel cell stack (not shown) has a stack structure in which a plurality of single cells are stacked in series, and is composed of, for example, a solid polymer electrolyte fuel cell.

  The oxidizing gas supply system to the fuel cell 2 includes an air compressor 5, an intercooler 3, and an intercooler cooling water pump 4 (see FIG. 1). The air compressor 5 compresses air taken from outside air through an air filter (not shown). The intercooler 3 cools the air that has been compressed to a high temperature. The intercooler cooling water pump 4 circulates cooling water for cooling the intercooler 3. The air compressed by the air compressor 5 is cooled by the intercooler 3 in this way, passes through the humidifier 17, and is supplied to the cathode (oxygen electrode) of the fuel cell 2. The oxygen off-gas after being subjected to the cell reaction of the fuel cell 2 flows through the cathode off-gas channel 16 and is exhausted out of the system. This oxygen off gas is in a highly moist state because it contains moisture generated by the cell reaction in the fuel cell 2. Therefore, the humidifier 17 exchanges moisture between the oxidant gas before supply in a low wet state and the oxygen off gas in high wet state flowing through the cathode offgas flow path 16, and the oxidant gas supplied to the fuel cell 2 Humidify moderately.

  The hydrogen gas supply system to the fuel cell 2 is configured as a system for supplying hydrogen as a fuel to the fuel cell 2. For example, in the case of this embodiment, a plurality of (for example, four) high-pressure hydrogen tanks 21 are arranged in parallel as hydrogen storage sources, and are led to the anode (fuel electrode) of the fuel cell 2 by the hydrogen gas supply path 23. (See FIG. 3). Each high-pressure hydrogen tank 21 is provided with a high-pressure hydrogen tank valve 22 which is a kind of low-pressure auxiliary machine. The hydrogen gas supply path 23 is provided with a regulator 24 for reducing the gas pressure, and an injector 25 that functions as a flow rate adjusting valve and a modulatable pressure valve. The injector 25 can adjust the flow rate and pressure of hydrogen gas with high accuracy by controlling the hydrogen gas injection time and injection timing by the control device 13. Although not particularly shown in FIGS. 1 and 3, the hydrogen gas supply system is provided with a fuel cell inlet valve, a fuel gas circulation path and the like in addition to these. The fuel gas circulation path is a return gas flow path for recirculating unreacted fuel gas to the fuel cell 2. The gas flow path is provided with a fuel cell outlet valve, a hydrogen pump, a check valve and the like from upstream to downstream. .

  A cooling water pipe 11 for circulating the cooling water is provided at the inlet / outlet of the cooling water (LLC) of the fuel cell 2. The cooling water pipe 11 is provided with a water pump 10 that sends out the cooling water and a flow path switching valve 12 for adjusting the cooling water supply amount.

  A part of the DC power generated by the fuel cell 2 is stepped down by the high voltage converter 14 and charged to a high voltage battery (secondary battery) 15 that functions as a high voltage power storage device. The motor inverter (traction inverter) 7 converts the DC power supplied from the fuel cell 2 into AC power and supplies the AC power to the traction motor 8. Further, the water pump inverter 9 converts the DC power supplied from the fuel cell 2 into AC power and supplies the AC power to the water pump 10. Further, the air compressor driving inverter 6 converts the DC power supplied from the fuel cell 2 into AC power and supplies the AC power to the air compressor 5.

  For example, if the control device 13 is mounted on a fuel cell vehicle, the control device 13 obtains the system required power (the sum of the vehicle travel power and the auxiliary power) based on the accelerator opening, the vehicle speed, etc. It is a device that controls the system to match the power. More specifically, the control device 13 controls the air compressor driving inverter 6 to adjust the rotational speed and the oxidizing gas supply amount of a motor (not shown) that drives the air compressor 5. Further, the temperature of the compressed air is adjusted by controlling the water pump 4 for cooling the intercooler. Further, the motor inverter 7 is controlled to adjust the rotational speed of the traction motor 8, and the water pump inverter 9 is controlled to adjust the water pump 10. Further, the operation point (output voltage, output current) of the fuel cell 2 is adjusted by controlling the high-voltage converter 14 so that the output power of the fuel cell 2 matches the target power.

  The DC / DC converter 18 steps down a part of the DC power on the high voltage circuit side and supplies it to the low voltage circuit side. A part of the stepped-down DC power is charged in a low voltage battery (secondary battery) 19 that functions as a low voltage power storage device, and a part is used as power for driving the low voltage auxiliary machine 20 (see FIG. 1). The low-pressure auxiliary machine 20 refers to various devices that are driven at a low pressure (for example, 12V). For example, the high-pressure hydrogen tank valve 22 (see FIG. 3), or an air conditioner (air conditioner) for a fuel cell vehicle, a navigation system, for example. Various electric devices such as lights, pump devices, injector devices, turn signals (turn signal lamps), and the like are applicable. These low-voltage auxiliary machines 20 can also be driven by being supplied with power from the low-voltage battery 19. The DC / DC converter 18 interposed between the high-voltage circuit and the low-voltage circuit in this way decreases the voltage on the low-voltage side by supplying power from the high-voltage side to the low-voltage side, for example, at the time of starting the system. In other words, it has a role of assisting to avoid this. That is, when the low-voltage auxiliary machine 20 is started only with the low-voltage battery 19, if the power consumption is large, there is a possibility that the voltage is lowered. Therefore, the DC / DC converter 18 is started and the high-voltage side battery is moved to the low-voltage side. The power or voltage on the low voltage side can be assisted (assisted) by supplying the power.

  Subsequently, embodiments of the present invention will be described below. As described above, in the present embodiment, the driving mode of the low-voltage auxiliary machine 20 is changed according to the state of the low-voltage battery (low-voltage power storage device) 19 when the fuel cell system 1 is started. Hereinafter, a specific example will be described (see FIG. 2). Here, as an example of the low-pressure auxiliary machine 20, a case where the high-pressure hydrogen tank valve 22 with relatively large power consumption is driven will be described as an example.

  First, when starting the fuel cell system 1 (step 1), the IG (ignition) device is operated to start the start (step 2). After the start, it is determined whether or not the voltage of the low voltage battery 19 has decreased (step 3). If the voltage has not decreased, the process proceeds to step 4; if it has decreased, the process proceeds to step 8.

  If the voltage of the low-voltage battery 19 has not decreased, the high-pressure hydrogen tank valve (low-pressure auxiliary machine) 22 is driven to open (step 4). At this time, in the present embodiment, the high-pressure hydrogen tank valve 22 is driven only by the power supplied from the low-voltage battery 19 without waiting for the activation of the DC / DC converter 18. In this case, a plurality of high-pressure hydrogen tank valves 22 can be driven at the same time, but it is preferable to start these high-pressure hydrogen tank valves 22 sequentially at different times from the viewpoint of dispersing the inrush current. As a result, it is possible to avoid the current from being concentrated and to avoid the voltage of the low-voltage battery 19 from rapidly decreasing as much as possible.

  If the high-pressure hydrogen tank valve 22 is driven and opened in step 4, it waits for the hydrogen pressure in the hydrogen gas supply path 23 to increase (step 5). If the hydrogen pressure rises (Yes in step 6), it can be determined that the start-up operation is proceeding properly without starting the DC / DC converter 18. In this case, the fuel cell system 1 is started. The operation is continued (step 13). On the other hand, if the hydrogen pressure does not increase (No in step 6), the high-pressure hydrogen tank valve 22 is once closed (step 7), and the process proceeds to step 8.

  When the process proceeds to step 8, that is, when the voltage of the low-voltage battery 19 is decreased at step 3 or when the voltage is low before starting or when the hydrogen pressure is not increased at step 6, the high pressure is increased. When the hydrogen tank valve 22 is closed, it waits for the start of the DC / DC converter 18 to be completed (step 8). Since the DC / DC converter 18 also has a role of assisting power from the high voltage side, in this case, the voltage of the low voltage battery 19 is lowered by receiving the assist after the DC / DC converter 18 is activated. Can be avoided.

  When the activation of the DC / DC converter 18 is completed (Yes in step 8), the high-pressure hydrogen tank valve 22 is driven to open (step 9). Thereafter, the process waits for the hydrogen pressure to rise (step 10). When the hydrogen pressure rises (Yes in step 10), the starting operation of the fuel cell system 1 is continued as it is (step 13). On the other hand, if the hydrogen pressure does not increase (No in step 11), the high-pressure hydrogen tank valve 22 is once closed (step 12), the process returns to step 9 and the high-pressure hydrogen tank valve 22 is opened again. In this case, the high-pressure hydrogen tank valve 22 is repeatedly opened and closed until the hydrogen pressure rises to a predetermined value (see FIG. 2).

  According to the control method at the time of starting as described above, it is possible to improve the startability of the fuel cell system 1 while avoiding a voltage drop. That is, in the current fuel cell system 1, it is common that a plurality of high-pressure hydrogen tanks 21 are installed, and each of them has a high-pressure hydrogen tank valve 22. However, in this embodiment, the startability is improved by starting the system without waiting for the start of the DC / DC converter 18 to the extent possible.

  In addition, when at least a part of the low-pressure auxiliary machine 20 is not activated, more specifically, when at least a part of the high-pressure hydrogen tank valve 22 is not activated, the result that the hydrogen pressure does not rise sufficiently is obtained. (Steps 6 and 11), it is assumed that the DC / DC converter 18 is activated after waiting for completion of activation. In this case, for example, when the low-voltage battery 19 is originally weak, or when the battery voltage is temporarily lowered before starting, the situation in such a system can be considered. In addition, since it can be started in a state where it can receive power assistance from the high voltage side, at least the same startability as before can be ensured.

  The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention. For example, in the above-described embodiment, the case where the plurality of high-pressure hydrogen tanks 21 (and the high-pressure hydrogen tank valves 22 associated therewith) are arranged in parallel is illustrated, but the present invention is not limited to this, and is arranged in series. Even with such a structure, the present invention can be applied. In short, a plurality of valves are arranged in the hydrogen gas supply system, and the voltage drop is reduced by applying the present invention even in a system in which these valves are driven sequentially or simultaneously when the system is started. It is possible to improve the startability while avoiding the above.

  In the present embodiment, the high-pressure hydrogen tank valve 22 is described as an example of the low-pressure auxiliary machine 20, but this is also only a preferable example. In short, it is possible to improve the startability while avoiding the voltage drop by making the auxiliary start-up method unique to the voltage drop of the low voltage battery 19 at the time of system start-up, Not limited to the high-pressure hydrogen tank valve 22, for example, various hydrogen gas supply valves arranged in a hydrogen gas supply system for supplying hydrogen gas to the fuel cell 2, or an air pressure regulating valve, a cooling three-way valve, and a cooling valve Needless to say, the present invention can also be applied to a pump or the like, or an actuator for supplying hydrogen gas.

  Or it can also be as follows. That is, when a closed valve (for example, the high-pressure hydrogen tank valve 22) is opened, an inrush current (rush current) that is much larger than a steady current flows in a short time, and then a current lower than that In general, the open state is maintained by passing a holding current of. On the other hand, when the high-pressure hydrogen tank valve 22 is once closed and then opened again (in the case of step 7 → step 8 → step 9 or step 12 → step 9) as shown in the flowchart of FIG. This time (at least longer than the conventional time) may be allowed to flow to ensure the opening. For example, even if the high-pressure hydrogen tank valve 22 does not operate for some reason, if the inrush current is made to flow longer than before, the operation can be performed more reliably while taking into account the state of the valve. It becomes possible to make it.

  Furthermore, in this embodiment, when it is determined that the hydrogen pressure does not increase after waiting for the hydrogen pressure increase (No in Step 5 and Step 6), the high-pressure hydrogen tank valve 22 is temporarily closed (Step 7). There are various reasons why the hydrogen pressure does not increase as described above. For example, a part of the high-pressure hydrogen tank valve 22 (and an auxiliary device such as an actuator related to hydrogen supply using a low-pressure (for example, 12V) power source) Or it may also include not all working well or not working at all. Even when the high-pressure hydrogen tank valve 22 or the like does not operate as described above, the high-pressure hydrogen tank valve 22 is temporarily closed as in the above-described embodiment, and the DC / DC converter 18 is activated. If the process of opening the high-pressure hydrogen tank valve 22 again is performed, the auxiliary machine such as the high-pressure hydrogen tank valve 22 can be operated more reliably even if the initial voltage or current is insufficient. Is possible.

  Further, when starting the fuel cell system 1 in this way, it is preferable that at least a part of the low-pressure auxiliary machine 20 in the system that is not necessary for starting the fuel cell system 1 is stopped. (See step 3 ′ in FIG. 4). By doing so, at the time of startup of the fuel cell system 1, at least power consumption can be suppressed and the voltage can be prevented from decreasing. Examples of such a low pressure auxiliary machine 20 include an air conditioner, a navigation system, lights, a blinker (turn signal lamp), etc., among the various devices described above. These low-voltage auxiliary machines 20 can be driven after the DC / DC converter 18 is started, so that the voltage drop can be suppressed, and the fuel cell system 1 can be started earlier than before.

  Here, a specific example will be given to explain that the present invention can be variously modified (see FIG. 5).

  If the high-pressure hydrogen tank valve (an example of a low-pressure auxiliary machine) 22 is driven only by the power supplied from the low-voltage battery 19 without waiting for the DC / DC converter 18 to start, the time can be reduced from the viewpoint of distributing the inrush current. As described above, it is preferable to sequentially start by shifting, but this will be described in more detail as follows (see FIG. 5). In the following, a plurality of (for example, four) high-pressure hydrogen tanks 21 are arranged in parallel as hydrogen storage sources, and are led to the anode (fuel electrode) of the fuel cell 2 by the hydrogen gas supply path 23. Is the same as described above (see FIG. 3).

  First, when starting the fuel cell system 1 (step 21), the IG (ignition) device is operated to start the start (step 22). After the start, one of a plurality of (for example, four) high-pressure hydrogen tank valves 22 is opened (step 23). Next, the system waits for the start of the DC / DC converter 18 to be completed (step 24), and when completed (Yes in step 24), the remaining high-pressure hydrogen tank valves 22 are sequentially opened (step 25). Thus, while sequentially opening the high-pressure hydrogen tank valve 22, it is determined whether or not the hydrogen pressure has increased to a predetermined value (step 26). If the hydrogen pressure has increased (Yes in step 26), the fuel cell system 1 is started ( The (start) operation is continued (step 27).

  As described above, in the fuel cell system 1 including a plurality of low-pressure auxiliary machines (for example, high-pressure hydrogen tank valves), the inrush current (rush current) is dispersed by starting them at different times, and the current and load It is preferable to avoid the concentration of the voltage, and it is possible to suppress a voltage drop in the low-voltage power supply system.

1 is a diagram showing a schematic configuration of a fuel cell system according to an embodiment of the present invention. It is a flowchart which shows the content of the control in embodiment of this invention. It is a figure which shows the outline of the hydrogen gas supply system in embodiment of this invention. It is the flowchart which described and showed only the main flow about the content of the control at the time of making it stop the low voltage | pressure auxiliary machine unnecessary for system starting (starting). It is a flowchart which shows the control content at the time of making it open a some high pressure hydrogen tank valve sequentially.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell system, 2 ... Fuel cell (fuel cell stack), 15 ... High voltage battery (high voltage electrical storage device), 18 ... DC / DC converter, 19 ... Low voltage battery (low voltage electrical storage device), 20 ... Low voltage auxiliary machine, 22 ... High-pressure hydrogen tank valve (an example of a low-pressure auxiliary machine)

Claims (12)

In a fuel cell system including a fuel cell and a low voltage low-voltage power source among secondary batteries having different voltages,
A fuel cell system that drives or stops a low-pressure auxiliary machine driven by the low-voltage power source according to the state of the low-voltage power source system when the fuel cell system is started.   2. The fuel cell system according to claim 1, wherein at least a part of the low-pressure auxiliary machine that is unnecessary for starting the fuel cell system is stopped. 3.   3. The fuel cell system according to claim 1, wherein among the low-pressure auxiliary machines, those necessary for starting the fuel cell system are started at different times.   When the voltage of the low-voltage power supply is lower than a predetermined value, the low-voltage auxiliary machine is activated after the DC / DC converter interposed between the low-voltage power supply and the high-voltage power supply having a voltage higher than the low-voltage power supply is activated. The fuel cell system according to claim 1 or 2, wherein   When at least a part of the low-voltage auxiliary machine does not start, the low-voltage auxiliary machine is operated after a DC / DC converter interposed between the low-voltage power supply and a high-voltage power supply having a voltage higher than the low-voltage power supply is started. The fuel cell system according to claim 1, wherein the fuel cell system is activated.   The low-pressure auxiliary machine is a hydrogen gas supply valve or a hydrogen gas supply actuator arranged in a hydrogen gas supply system for supplying hydrogen gas to the fuel cell. A fuel cell system according to claim 1. A high-voltage power storage device, a low-voltage power storage device having a lower voltage than the high-voltage power storage device, a low-voltage auxiliary machine driven mainly by the power of the low-voltage power storage device, and a DC interposed between the high-voltage power storage device and the low-voltage power storage device In a control method at the time of starting a fuel cell system provided with
A control method at the time of start-up of the fuel cell system, wherein a driving mode of the low-voltage auxiliary machine is changed according to a state of the low-voltage power storage device at the time of start-up.   The control method at the time of starting the fuel cell system according to claim 7, wherein driving of at least a part of the auxiliary equipment unnecessary for starting the fuel cell system is stopped.   The control method at the time of starting the fuel cell system according to claim 7 or 8, wherein among the low-pressure auxiliary devices, auxiliary devices required for starting the fuel cell system are started at different times.   9. The start of the fuel cell system according to claim 7, wherein when the voltage of the low-voltage power storage device is lower than a predetermined value, the low-voltage auxiliary machine is started after the DC / DC converter is started. Control method at the time.   8. When starting up the fuel cell system according to claim 7, wherein, when at least a part of the low-pressure auxiliary machine does not start up, the DC / DC converter is started up and then the low-pressure auxiliary machine is started up. Control method. The low-pressure auxiliary machine is a hydrogen gas supply valve or a hydrogen gas supply actuator arranged in a hydrogen gas supply system for supplying hydrogen gas to the fuel cell. A control method at startup of the fuel cell system according to claim 1.

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