JP4673618B2 - Fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell system that uses a hydrogen storage alloy to warm up a fuel cell.

  In recent years, fuel cells that are clean and have high energy efficiency have attracted attention as power sources for fuel cell vehicles. In this fuel cell, air containing oxygen is supplied to the cathode side and hydrogen is supplied to the anode side, whereby electricity is generated by reacting these hydrogen and oxygen.

  By the way, the fuel cell as described above exhibits its power generation performance to a maximum at a certain temperature, and has a characteristic that the power generation performance is lowered at a low temperature. Therefore, when starting a fuel cell in winter or in a cold region, it is necessary to warm up the fuel cell (warm up to a predetermined temperature). As a technique for solving such a problem, conventionally, at the time of starting the fuel cell, hydrogen gas to be supplied from the high-pressure hydrogen tank to the fuel cell is shunted and temporarily stored in the hydrogen storage alloy. A fuel cell system that recycles hydrogen gas by heating the fuel cell by heating the alloy, and releasing hydrogen gas from the hydrogen storage alloy and supplying it to the fuel cell after the warm-up is completed. Is known (see Patent Document 1).

  Specifically, the fuel cell system described in Patent Document 1 includes a fuel cell, a high-pressure hydrogen tank for supplying hydrogen gas to the fuel cell, a hydrogen supply path that connects the fuel cell and the high-pressure hydrogen tank, A shut-off valve for switching the communication state of the hydrogen supply path, an MH tank containing a hydrogen storage alloy, a single pipe connecting the hydrogen supply path and the MH tank, and an MH for switching the communication state of the pipe And a shut-off valve for use. In this fuel cell system, when the fuel cell is warmed up, hydrogen gas is supplied into the MH tank by opening the shut-off valve and the MH shut-off valve, and after the warm-up is completed, the hydrogen storage in the MH tank is performed. When releasing the hydrogen gas occluded with the alloy, the pressure on the downstream side of the shut-off valve is lowered by closing the shut-off valve to promote the release of hydrogen gas from the MH tank. This fuel cell system releases all the hydrogen gas stored by the hydrogen storage alloy (after the MH tank is empty), then closes the MH shutoff valve and opens the shutoff valve. The normal operation of the fuel cell is started. In the following description, for convenience, “releasing the hydrogen gas stored by the hydrogen storage alloy” is also referred to as “MH regeneration”.

JP 2003-86213 A

  By the way, in the fuel cell system as described above, the amount of hydrogen gas released from the hydrogen storage alloy is smaller than the amount of hydrogen gas released from the high-pressure hydrogen tank. Therefore, even if a high output request command is output to the fuel cell during MH regeneration and the fuel cell is operated at a high output, the fuel cell can be output at a high output only with hydrogen gas released from the hydrogen storage alloy. There was a problem that it could not be operated.

  Therefore, an object of the present invention is to provide a fuel cell system capable of operating a fuel cell at a high output even when a high output request command is output to the fuel cell during MH regeneration. To do.

This onset bright to solve the above problems, a fuel cell that generates electricity by reaction between hydrogen gas and oxidizing agent gas, and a high pressure hydrogen supply means for supplying high-pressure hydrogen gas to the fuel cell, the high-pressure hydrogen as the fuel cell A hydrogen gas supply path that connects the supply means, an on-off valve that switches a communication state of the hydrogen gas supply path, and a hydrogen storage alloy, and when the fuel cell needs to be warmed up when the system is started, An MH tank for warming up the fuel cell by storing hydrogen gas in the alloy, a pressure sensor for detecting the tank internal pressure in the MH tank, and the downstream side of the on-off valve in the hydrogen gas supply path MH flow path connecting the MH tank, the MH shut-off valve for switching the communication state of the MH flow path, and the hydrogen gas stored in the MH tank after completion of warming up of the fuel cell Before When supplied to the fuel cell, the on-off valve closed, said MH cutoff valve is opened, by releasing the occluded hydrogen gas to the hydrogen absorbing alloy, MH reproducing the hydrogen storage alloy Regeneration means, target hydrogen gas pressure calculation means for calculating a target hydrogen gas pressure of hydrogen gas supplied to the fuel cell based on an output request command given to the fuel cell from the outside, and the MH regeneration means While supplying the hydrogen gas stored in the MH tank to the fuel cell, the on- off valve is closed when the tank internal pressure is higher than the target hydrogen gas pressure , and the tank internal pressure is set to the target hydrogen gas. fuel cell cis characterized that you and a high power operating means for supplying hydrogen gas to the fuel cell by opening the on-off valve from the high pressure hydrogen supply means when not higher than the gas pressure It is a non.

  Here, “to open / close the valve” means to maintain the open / close valve in the closed state when the original state of the open / close valve is closed. When it is in a closed state, it means closing the on-off valve. Similarly, “opening the MH shut-off valve” means that when the original state of the MH shut-off valve is an open state, the MH shut-off valve is maintained in that state. When the original state of the shut-off valve is closed, it means that the MH shut-off valve is opened. “High output” refers to an output that is equal to or higher than an output value (current value) that cannot be extracted from the fuel cell with the low-pressure hydrogen gas supplied from the MH tank.

According to such a fuel cell system , when supplying hydrogen gas stored in the MH tank to the fuel cell (performing MH regeneration), the on-off valve is closed and the MH cutoff valve is opened. Thereby, the pressure on the downstream side of the on-off valve is reduced, and MH regeneration is promoted. When a high output request command is output to the fuel cell during MH regeneration, the on-off valve is opened. As a result, the high-pressure hydrogen gas is supplied from the high-pressure hydrogen supply means to the fuel cell, so that the fuel cell can be operated at a high output.

In the fuel cell system, it is preferable that the high-power operating means closes the MH shutoff valve when the on-off valve is opened.

According to such a fuel cell system, when a high output request command is output to the fuel cell during MH regeneration, the on-off valve is opened and the MH cutoff valve is closed. Thereby, since the hydrogen gas released from the high-pressure hydrogen supply means is not supplied to the MH tank but supplied only to the fuel cell, it is possible to more reliably realize the operation of the fuel cell with high output. it can.

The present invention also includes a fuel cell that generates electricity by a reaction between hydrogen gas and oxidant gas, a high-pressure hydrogen supply unit that supplies high-pressure hydrogen gas to the fuel cell, the fuel cell, and the high-pressure hydrogen supply unit. When a hydrogen gas supply path to be connected, an on-off valve for switching the communication state of the hydrogen gas supply path, and a hydrogen storage alloy are built in , and it is necessary to warm up the fuel cell at the time of system start -up , hydrogen gas is supplied to the hydrogen storage alloy An MH tank that warms up the fuel cell by occluding the fuel, a pressure sensor that detects a tank internal pressure in the MH tank, an MH channel that connects the hydrogen gas supply path and the MH tank, and A discharge gas flow channel connecting a portion of the hydrogen gas supply channel downstream of the on-off valve and the MH tank; a MH shutoff valve for switching a communication state of the MH flow channel; and the discharge flow signal. In the street A check valve which allows only the flow of the hydrogen gas to the hydrogen gas supply path from the MH tank have supplied after completion of the warm-up of the fuel cell, the hydrogen gas stored in the MH tank to the fuel cell Sometimes, both the on-off valve and the MH shut-off valve are closed, and by releasing the hydrogen gas stored in the hydrogen storage alloy, MH regeneration means for regenerating the hydrogen storage alloy, and externally The target hydrogen gas pressure calculating means for calculating the target hydrogen gas pressure of the hydrogen gas supplied to the fuel cell based on the output request command given to the fuel cell, and the MH regeneration means stored in the MH tank. in midst of supplying hydrogen gas to the fuel cell, closing the on-off valve when the tank pressure is higher than the target hydrogen gas pressure, the tank pressure is the target hydrogen pressure And high power operating means for supplying hydrogen gas to the fuel cell from said high pressure hydrogen supply means is opened to the on-off valve in case not high, a fuel cell system comprising a call with a.

According to such a fuel cell system , when performing MH regeneration, both the on-off valve and the MH shutoff valve are closed. As a result, the pressure on the downstream side of the on-off valve decreases, and the release of hydrogen gas from the discharge channel is promoted. When a high output request command is output to the fuel cell during MH regeneration, the on-off valve is opened. As a result, the high-pressure hydrogen gas is supplied from the high-pressure hydrogen supply means to the fuel cell, so that the fuel cell can be operated at a high output. At this time, the hydrogen gas released from the high-pressure hydrogen supply means is prohibited from flowing into the MH tank by the check valve and is supplied only to the fuel cell. Therefore, the fuel cell is operated at a high output. It can be realized more reliably.

The present invention also includes a fuel cell that generates electricity by a reaction between hydrogen gas and oxidant gas, a high-pressure hydrogen supply unit that supplies high-pressure hydrogen gas to the fuel cell, the fuel cell, and the high-pressure hydrogen supply unit. When a hydrogen gas supply path to be connected, an on-off valve for switching the communication state of the hydrogen gas supply path, and a hydrogen storage alloy are built in , and it is necessary to warm up the fuel cell at the time of system start -up , hydrogen gas is supplied to the hydrogen storage alloy An MH tank that warms up the fuel cell by storing the pressure, a pressure sensor that detects a tank internal pressure in the MH tank, a portion of the hydrogen gas supply path that is downstream of the on-off valve, Provided on the upstream side of the connecting portion between the MH flow path connecting the MH tank, the MH shutoff valve for switching the communication state of the MH flow path, and the hydrogen gas supply path and the MH flow path. , the high Reducing the pressure of hydrogen gas released from the hydrogen supply unit, and a primary variable regulator that arbitrarily set the pressure after decompression, the downstream side of the connecting portion of the hydrogen gas supply channel and said MH passage And a secondary variable regulator that can further depressurize the hydrogen gas depressurized by the primary variable regulator and optionally set the pressure after depressurization, and after completion of warming up of the fuel cell, the MH tank When supplying the hydrogen gas stored in the fuel cell to the fuel cell, the pressure on the downstream side of the primary variable regulator is smaller than the pressure in the tank and the secondary variable with the on-off valve being opened. and sets over pressure downstream of the regulator, by the MH cutoff valve opened, by releasing the occluded hydrogen gas to the hydrogen storage alloy, the hydrogen storage alloy re And MH reproduction means for, based on an output request command, which is from the outside to the fuel cell, and the target hydrogen pressure calculation means for calculating a target hydrogen pressure of the hydrogen gas supplied to the fuel cell, the MH reproducing means While the hydrogen gas stored in the MH tank is being supplied to the fuel cell, the open / close valve is opened when the tank internal pressure is higher than the target hydrogen gas pressure. When the pressure on the downstream side of the secondary variable regulator is set lower than the pressure in the tank and equal to or higher than the pressure on the downstream side of the secondary variable regulator, and the pressure in the tank is not higher than the target hydrogen gas pressure to leave open the on-off valve sets a pressure downstream of the primary variable regulator above the target hydrogen gas pressure, the second variable regulator And the high output operation means for setting the pressure of the downstream side in the target hydrogen gas pressure, a fuel cell system comprising a call with a.

According to such a fuel cell system , when performing MH regeneration, the pressure on the downstream side of the primary variable regulator is smaller than the pressure in the MH tank while the on-off valve remains open, and the secondary The pressure is set to be equal to or higher than the pressure on the downstream side of the variable regulator, and the MH cutoff valve is opened. As a result, the pressure on the downstream side of the primary variable regulator is lower than the pressure in the MH tank, the release of hydrogen gas from the MH tank is promoted, and the hydrogen gas is satisfactorily supplied to the fuel cell. Become. When a high output request command is output to the fuel cell during MH regeneration, the pressure on the downstream side of the primary variable regulator corresponds to the high output request command while the on-off valve remains open. The pressure is set to be equal to or higher than the FC required pressure, and the downstream pressure of the secondary variable regulator is set to the FC required pressure. As a result, the high-pressure hydrogen gas is supplied from the high-pressure hydrogen supply means to the fuel cell, so that the fuel cell can be operated at a high output.

In the fuel cell system, the high output operation means in controlling the primary variable regulator and the secondary variable regulator, closing the MH cutoff valve is preferred.

According to such a fuel cell system, when a high output request command is output to the fuel cell during MH regeneration, the primary variable regulator and the secondary variable regulator are appropriately controlled as described above, The MH shut-off valve is closed. Thereby, since the hydrogen gas released from the high-pressure hydrogen supply means is not supplied to the MH tank but supplied only to the fuel cell, it is possible to more reliably realize the operation of the fuel cell with high output. it can.

According to the present invention, the following effects are obtained.
When a high output request command is output during MH regeneration, high-pressure hydrogen gas is supplied from the high-pressure hydrogen supply means to the fuel cell by opening the on-off valve. The battery can be operated at a high output.

Also, when a high output request command is output during MH regeneration, the on-off valve is opened and the MH shut-off valve is closed, so that the hydrogen gas released from the high-pressure hydrogen supply means is supplied only to the fuel cell. Since it is supplied, it is possible to more reliably realize the operation of the fuel cell at a high output.

Further, when a high output request command is output during MH regeneration, the on-off valve is opened and the check valve operates to supply high-pressure hydrogen gas only from the high-pressure hydrogen supply means to the fuel cell. The fuel cell can be operated at a high output.

Furthermore , when a high output request command is output during MH regeneration, the pressure on the downstream side of the primary variable regulator is equal to or higher than the FC required pressure corresponding to the high output request command while the on-off valve remains open. In addition, since the pressure downstream of the secondary variable regulator is set to the FC required pressure, high-pressure hydrogen gas is supplied from the high-pressure hydrogen supply means to the fuel cell. It is possible to operate with output.

Further, during the MH regeneration, when a high output request command is output to the fuel cell, the primary variable regulator and the secondary variable regulator are appropriately controlled, and the MH shutoff valve is closed, so that the high pressure hydrogen Since the hydrogen gas released from the supply means is supplied only to the fuel cell without being supplied to the MH tank, it is possible to more reliably realize the operation of the fuel cell with high output.

[First Embodiment]
Next, a first embodiment according to the present invention will be described in detail with reference to the drawings as appropriate. In the drawings to be referred to, FIG. 1 is a configuration diagram showing the fuel cell system according to the first embodiment, and FIG. 2 is a flowchart showing the operation of the ECU. 3 is a block diagram showing the flow of hydrogen gas when the fuel cell is warmed up, FIG. 4 is a block diagram showing the flow of hydrogen gas during MH regeneration, and FIG. 5 is a high output request command output during MH regeneration. It is a block diagram which shows the flow of hydrogen gas when it was made.

  As shown in FIG. 1, the fuel cell system S mainly includes an air supply system 1, a hydrogen supply system 2, an MH tank 3, a fuel cell 4, and an ECU (control unit) 5.

  The air supply system 1 includes a compressor 6 that compresses and supplies air, an air supply passage 61 that guides the air from the compressor 6 to the fuel cell 4, and an air exhaust that guides the air discharged from the fuel cell 4 to the outside. The flow path 62 is mainly provided. The air discharge channel 62 is provided with a back pressure valve (not shown) for controlling the pressure (back pressure) on the cathode electrode side.

  The hydrogen supply system 2 mainly includes a high-pressure hydrogen tank (high-pressure hydrogen supply means) 7, a hydrogen gas supply path 8, and a circulation path 9.

  The high-pressure hydrogen tank 7 is filled with high-pressure hydrogen gas. This hydrogen gas is released by opening a shut-off valve (not shown) provided in the high-pressure hydrogen tank 7 or an intermediate-pressure valve 81 described later. The fuel gas is supplied to the fuel cell 4 through the hydrogen gas supply path 8. The hydrogen gas in the high-pressure hydrogen tank 7 is also supplied into the MH tank 3 by opening the MH shut-off valve 33 described later in addition to the shut-off valve and the intermediate pressure valve 81 described above. It has become. The intermediate pressure valve 81 corresponds to an “open / close valve” in the claims.

  The hydrogen gas supply path 8 is a flow path that connects the high-pressure hydrogen tank 7 and the fuel cell 4, and the primary regulator R 1, the intermediate pressure valve 81, and the secondary variable regulator CR 2 are arranged in order from the high-pressure hydrogen tank 7 side. Is provided. The primary regulator R1 and the secondary variable regulator CR2 are both pressure reducing valves for reducing the pressure of the hydrogen gas supplied from the upstream side. Further, the secondary variable regulator CR2 is appropriately controlled by the ECU 5. This is a pressure reducing valve that can adjust the downstream pressure appropriately. Therefore, the pressure relationship from the high-pressure hydrogen tank 7 to the fuel cell 4 is the highest from the high-pressure hydrogen tank 7 to the primary regulator R1, and then the primary regulator R1 to the secondary variable regulator CR2 is the highest. The relationship from the regulator CR2 to the fuel cell 4 is the lowest. In the following description, for the sake of convenience, the line between the high-pressure hydrogen tank 7 and the primary regulator R1 is the high-pressure hydrogen line 8a, the line between the primary regulator R1 and the secondary variable regulator CR2 is the medium-pressure hydrogen line 8b, A line between the secondary variable regulator CR2 and the fuel cell 4 is referred to as a low-pressure hydrogen line 8c.

  The intermediate pressure valve 81 is a valve for switching the communication state (blocking / communication) of the hydrogen gas supply path 8, and is provided at an appropriate position of the intermediate pressure hydrogen line 8 b (specifically, the hydrogen gas supply path 8 and the MH flow path described later). 32 and the primary regulator R1). When the intermediate pressure valve 81 is closed during operation of the fuel cell 4, hydrogen gas in the intermediate pressure hydrogen line 8 b and the low pressure hydrogen line 8 c on the downstream side of the intermediate pressure valve 81 is consumed by the fuel cell 4. Thus, the inside of the intermediate pressure hydrogen line 8b and the low pressure hydrogen line 8c is reduced in pressure.

  The circulation channel 9 is connected to the outlet 4b of the fuel cell 4 and the low-pressure hydrogen line 8c so that the unused hydrogen gas discharged from the fuel cell 4 can be returned to the fuel cell 4 again. Although not shown, the circulation channel 9 is appropriately provided with an ejector or a pump for circulating hydrogen gas. Further, in this circulation flow path 9, a purge hydrogen pipe for discharging hydrogen gas containing impurities contained in the hydrogen gas and water generated in the fuel cell 4 to a diluter (not shown). 91 is connected. The hydrogen gas in the circulation passage 9 is intermittently purged (discharged) from the fuel cell 4 to the diluter by appropriately opening and closing a purge valve 92 provided at an appropriate position of the purge hydrogen pipe 91 by the ECU 5. ).

  The MH tank 3 is a container in which the hydrogen storage alloy 31 is housed. The MH tank 3 generates heat by storing the hydrogen gas supplied from the high-pressure hydrogen tank 7 in the hydrogen storage alloy 31, and the heat is supplied to the fuel via the cooling water. It is transmitted to the battery 4. The MH tank 3 is configured such that heat generated by the power generation of the fuel cell 4 is transmitted via cooling water, and the hydrogen storage alloy 31 is heated by this heat, whereby the hydrogen storage alloy 31 is heated. The hydrogen gas occluded in is returned to the intermediate pressure hydrogen line 8b. The introduction of the hydrogen gas into the MH tank 3 and the discharge of the hydrogen gas from the MH tank 3 to the intermediate pressure hydrogen line 8b are performed by the single MH flow path 32. .

  The hydrogen storage alloy 31 is capable of storing the surrounding hydrogen gas by being cooled to a predetermined temperature (first temperature), and to a predetermined temperature (second temperature) higher than the first temperature. It has the property of being able to release hydrogen stored as a hydrogen gas when heated. Further, under the same temperature condition, the hydrogen storage alloy 31 releases hydrogen gas to the surroundings when the surrounding pressure becomes a predetermined pressure (release pressure) or lower, and the surrounding pressure is higher than the release pressure. When the pressure exceeds a predetermined pressure (occlusion pressure), the surrounding hydrogen gas is occluded.

Further, the hydrogen storage alloy 31 has a property of generating heat when storing hydrogen gas and absorbing heat when releasing hydrogen gas. In addition, as such a hydrogen storage alloy 31, the following can be used, for example.
AB ₂ type alloy (Laves phase _{alloys); TiCr 2, (Zr,} Ti) (Ni, Mn, V, Fe) 2 ·· AB 5 type alloys; LaNi _5, MnNi ₅ ·· BCC alloys; Ti-V- Cr, Ti-V-Mn, etc .; Mg-based alloy

  The MH flow path 32 is a flow path that connects the intermediate pressure hydrogen line 8b (specifically, a portion between the intermediate pressure valve 81 and the secondary variable regulator CR2) and the MH tank 3, and has an MH flow path at an appropriate position. An MH cutoff valve 33 is provided for switching the 32 communication states. A pressure sensor PS for detecting the pressure in the MH tank 3 is provided between the MH cutoff valve 33 and the MH tank 3.

  The fuel cell 4 generates power by an electrochemical reaction between hydrogen gas serving as fuel stored in the high-pressure hydrogen tank 7 and air (oxidant gas) supplied from the compressor 6. On the anode side of the fuel cell 4, a hydrogen gas supply path 8 is connected to the inlet 4a, and a circulation path 9 is connected to the outlet 4b. The fuel cell 4 is provided with a temperature sensor TS1 for directly detecting the temperature of the fuel cell 4, and the temperature of the cooling water heated by the fuel cell 4 is set in a flow path through which the cooling water passes. A temperature sensor TS2 for detection is provided.

  The ECU 5 controls each device of the fuel cell system S, mainly the compressor 6, the back pressure valve and shutoff valve, the intermediate pressure valve 81, the MH shutoff valve 33, the secondary variable regulator CR2, the purge valve 92, and the like. Yes. In particular, the ECU 5 appropriately heats the fuel cell 4 by the MH tank 3 (hereinafter also referred to as “warming up”) by appropriately controlling the intermediate pressure valve 81 and the MH cutoff valve 33 when the fuel cell 4 is started. ) And discharge of hydrogen gas from the MH tank 3 to the fuel cell 4 (hereinafter also referred to as “MH regeneration”).

  Specifically, as shown in FIG. 2, when the ECU 5 receives an ignition switch ON signal, which is an activation command for the fuel cell 4 (IGON), first, the temperature of the fuel cell (FC) 4 is predetermined. By determining whether or not the value is lower than the value T1 (step S1), it is determined whether or not the fuel cell 4 needs to be warmed up. In step S1, when the temperature of the fuel cell 4 is equal to or higher than the predetermined value T1 (No), the ECU 5 determines that it is not necessary to warm up the fuel cell 4, and shifts to the normal power generation mode (step S2). .

  In step S1, when the temperature of the fuel cell 4 is lower than the predetermined value T1 (Yes), the ECU 5 determines that the fuel cell 4 needs to be warmed up, and the above-described shut-off valve of the high-pressure hydrogen tank 7 is used. Then, the intermediate pressure valve 81 and the MH shutoff valve 33 are all opened (step S3). As a result, as shown in FIG. 3, hydrogen gas is supplied from the high-pressure hydrogen tank 7 to the MH tank 3, and the hydrogen storage alloy 31 in the MH tank 3 generates heat as the hydrogen gas is stored. It is transmitted to the fuel cell 4 through the cooling water, and the warm-up of the fuel cell 4 is started.

  As shown in FIG. 2, after step S3, the ECU 5 determines that the temperature of the cooling water (cooling water coming out of the fuel cell 4) after heat exchange with the fuel cell 4 is higher than a predetermined value T1. By determining whether or not the fuel cell 4 has become high (step S4), it is determined whether or not the fuel cell 4 has been warmed up. In step S4, when the temperature of the cooling water is equal to or lower than the predetermined value T1 (No), the ECU 5 determines that the fuel cell 4 still needs to be warmed up and repeats the processes of steps S3 and S4 again. Thus, the warm-up of the fuel cell 4 is continued. In step S4, when the temperature of the cooling water is higher than the predetermined value T1 (Yes), the ECU 5 determines that the warm-up of the fuel cell 4 has been completed, starts driving the compressor 6 and fuels the fuel. By appropriately taking out current from the battery 4, power generation by the fuel cell 4 is started (step S5), and then the MH regeneration mode is entered (step S6).

  When shifting to the MH regeneration mode, the ECU 5 first sets the current value corresponding to the output request command based on the output request command that is appropriately output by the user in order to determine the current value to be extracted from the fuel cell 4. The pressure of hydrogen gas and air (hereinafter, referred to as “FC required pressure”) necessary for taking out from the fuel is calculated (step S7). Here, the “output request command” corresponds to, for example, an accelerator signal output by stepping on the accelerator in a vehicle equipped with the fuel cell 4. When the FC required pressure is calculated in step S7, the secondary variable regulator CR2 is controlled to set the downstream pressure to the FC required pressure.

Then, after calculating the FC required pressure in step S7, the ECU 5 determines whether or not the pressure in the MH tank 3 is higher than the FC required pressure (step S8), so that the output request command is high. It is determined whether or not the current value is indicated, that is, whether or not a high output request command is output. In step S8, if the pressure in the MH tank 3 is higher than the FC required pressure (Yes), the ECU 5 determines that the high output request command is not output, closes the intermediate pressure valve 81, and moves to the MH. The use shut-off valve 33 is kept open (step S9). As a result, as shown in FIG. 4, the pressure on the downstream side of the intermediate pressure valve 81 decreases, and the supply of hydrogen gas (MH regeneration) from the MH tank 3 to the fuel cell 4 is performed satisfactorily. Here, the ECU 5 that executes the process of step S9 corresponds to “ MH regeneration means”.

  Then, as shown in FIG. 2, after step S9, the ECU 5 causes the temperature of the cooling water coming out of the fuel cell 4 to be higher than the predetermined value T2, and the pressure in the MH tank 3 to be higher than the predetermined value P1. By determining whether or not it is low (step S10), it is determined whether or not almost all of the hydrogen gas stored in the hydrogen storage alloy 31 has been released, that is, whether or not the interior of the MH tank 3 has been emptied. In step S10, if the temperature of the cooling water is equal to or lower than the predetermined value T2 or the pressure in the MH tank 3 is equal to or higher than the predetermined value P1 (No), the ECU 5 Is determined to remain, and the processing (MH regeneration) of steps S7 to S10 is repeated again.

During such MH regeneration (steps S7 to S10), when a high output request command is output to the fuel cell 4, the ECU 5 determines No in step S8 and determines the intermediate pressure valve 81. And close the MH shutoff valve 33 (step S11). Thereby, as shown in FIG. 5, since the high-pressure hydrogen gas is supplied from the high-pressure hydrogen tank 7 only to the fuel cell 4, the fuel cell 4 can be operated at a high output. Here, the ECU 5 that executes the process of step S11 corresponds to the “ high output operating means”.

  Note that the processing in step S11 is not performed only when the high output request command is output during MH regeneration as described above, but the high output request command is output immediately after the MH regeneration mode is started. It is also performed in the case (steps S6, S7, S8; No, S11). That is, the process of step S11 may be suddenly performed without passing through step S9. In this case, since the intermediate pressure valve 81 and the MH cutoff valve 33 are opened in step S3, step S11 is performed. Then, only the MH cutoff valve 33 is switched to the closed state. Further, when step S11 is performed before step S9 as described above, in step S9, the operation opposite to that in step S11 is performed, that is, the intermediate pressure valve 81 is changed from open to closed, and the MH cutoff valve 33 is closed. Both can be switched from open to open.

  After step S11, the process proceeds to step S10, which is performed when the process of step S11 is during MH playback (steps S7 to S10) or before MH playback (steps S6, S7, S8; No). Since it is a process, in step S10, it is always determined that hydrogen gas still remains in the MH tank 3 (No), and the process proceeds to steps S7 and S8. In step S8, if the high output request command is still output, the process proceeds to step S11 and the operation of the fuel cell 4 at high output is continued. In step S8, the high output request command is output. If not, the process proceeds to step S9 where MH playback is resumed or started.

  In step S10, when the temperature of the cooling water is greater than the predetermined value T2 and the pressure in the MH tank 3 is less than the predetermined value P1 (Yes), the ECU 5 determines that the MH tank 3 is empty. After the determination, the intermediate pressure valve 81 is opened and the MH shutoff valve 33 is closed (step S12). As a result, the MH regeneration process ends (END), and the normal operation of the fuel cell 4 is started.

According to the above, the following effects can be obtained in the first embodiment.
When a high output request command is output during the MH regeneration, the intermediate pressure valve 81 is opened and the MH shutoff valve 33 is closed, so that the high pressure hydrogen is directed from the high pressure hydrogen tank 7 only to the fuel cell 4. Since the gas is supplied, the fuel cell 4 can be operated at a high output even during MH regeneration.

[Second Embodiment]
The second embodiment of the fuel cell system according to the present invention will be described below. Since this embodiment is obtained by changing a part of the fuel cell system according to the first embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. In the drawings to be referred to, FIG. 6 is a block diagram showing a fuel cell system according to the second embodiment, and FIG. 7 is a flowchart showing the operation of the ECU. FIG. 8 is a block diagram showing the flow of hydrogen gas when the fuel cell is warmed up, FIG. 9 is a block diagram showing the flow of hydrogen gas during MH regeneration, and FIG. 10 is a high-output request command output during MH regeneration. It is a block diagram which shows the flow of hydrogen gas when it was made.

  As shown in FIG. 6, in addition to the structure of the first embodiment, the fuel cell system S ′ includes an appropriate position of the intermediate pressure hydrogen line 8b (specifically, connection between the hydrogen gas supply path 8 and the MH flow path 32). A portion 34d between the portion 8d and the secondary variable regulator CR2) and a discharge flow path 34 that connects the MH tank 3 are provided. The discharge flow path 34 is provided with a check valve 35 that allows only the flow of hydrogen gas from the MH tank 3 to the hydrogen gas supply path 8. Note that the MH flow channel 32 in this embodiment is a flow channel used only for introducing hydrogen gas into the MH tank 3, and may be connected to the upstream side of the intermediate pressure valve 81.

  Further, the ECU 5 'according to the present embodiment operates based on a slightly different flowchart from the ECU 5 according to the first embodiment. Therefore, in the following description of the operation of the ECU 5 ′, the same steps as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 7, when the ECU 5 ′ receives an ignition switch ON signal that is a start command for the fuel cell 4 (IGON), the ECU 5 ′ determines whether or not the fuel cell 4 needs to be warmed up in step S <b> 1. If it is determined that the warm-up is necessary (Yes), the fuel cell 4 is warmed up by repeating the processes of steps S3 and S4. The hydrogen gas at this time is supplied from the high-pressure hydrogen tank 7 to the MH tank 3 via the hydrogen gas supply path 8 and the MH flow path 32 as shown in FIG. When exiting from the warm-up process described above, the ECU 5 ′ starts power generation of the fuel cell 4 as shown in FIG. 7 (step S5), and shifts to a slightly different MH regeneration mode from the first embodiment. (Step S20).

After shifting to the MH regeneration mode, the ECU 5 ′ determines whether or not a high output request command is output from the user through the processes of steps S7 and S8, and if not (step S8). Yes), the intermediate pressure valve 81 and the MH shut-off valve 33 are both closed (step S21). As a result, as shown in FIG. 9, the pressure on the downstream side of the intermediate pressure valve 81 decreases, and the hydrogen gas is satisfactorily transferred from the MH tank 3 to the fuel cell 4 through the discharge flow path 34 and the hydrogen gas supply path 8. Will be supplied. Here, the ECU 5 ′ that executes the process of step S21 corresponds to “ MH regeneration means”. When the FC required pressure is calculated in step S7, the secondary variable regulator CR2 is controlled to set the downstream pressure to the FC required pressure.

After step S21, the ECU 5 'continues the MH regeneration (steps S7, S8, S21, S10) until it is determined in step S10 that the MH tank 3 has become empty. When a high output request command is output to the fuel cell 4 during such MH regeneration, the ECU 5 ′ determines No in step S8, and turns on only the intermediate pressure valve 81 in step S11. Open. As a result, as shown in FIG. 10, since the high-pressure hydrogen gas is supplied from the high-pressure hydrogen tank 7 only to the fuel cell 4, the fuel cell 4 can be operated at a high output. At this time, the hydrogen gas released from the high-pressure hydrogen tank 7 tries to go to the MH tank 3 through the MH flow path 32 and the discharge flow path 34, but is closed. Since it is blocked by the shutoff valve 33 and the check valve 35, it flows only to the fuel cell 4. Here, the ECU 5 ′ that executes the process of step S <b> 11 according to the second embodiment corresponds to the “ high output operating means”.

  If a high-output request command is output immediately after the MH regeneration mode is started (steps S20, S7, S8; No, S11), as in the first embodiment, in step S11 Only the MH shut-off valve 33 is switched to the closed state. And when step S11 is performed before step S21 in this way, in step S21, only the intermediate pressure valve 81 left open in step S11 is switched to close. In other words, the MH shut-off valve 33 is never opened once the MH shut-off valve 33 is closed, regardless of which of the steps S21 and S11 is passed first, and thereafter, the intermediate-pressure valve 81 is not opened. Only need to be controlled. Therefore, the power consumption required for the control can be suppressed to the extent that the control of the MH cutoff valve 33 can be omitted.

  In step S10, when the ECU 5 'determines that the MH tank 3 is empty (Yes), the intermediate pressure valve 81 is opened or kept open (step S22). As a result, the MH regeneration process ends (END), and the normal operation of the fuel cell 4 is started.

According to the above, the following effects can be obtained in the second embodiment.
When a high output request command is output during MH regeneration, the intermediate pressure valve 81 is opened, and the check valve 35 and the closed MH shut-off valve 33 act to operate the high pressure hydrogen tank 7 to the fuel cell 4. Since high-pressure hydrogen gas is supplied only to the fuel cell 4, the fuel cell 4 can be operated at a high output.

[Third Embodiment]
The third embodiment of the fuel cell system according to the present invention will be described below. Since this embodiment is obtained by changing a part of the fuel cell system according to the first embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. In the drawings to be referred to, FIG. 11 is a block diagram showing a fuel cell system according to the third embodiment, and FIG. 12 is a flowchart showing the operation of the ECU. FIG. 13 is a block diagram showing the flow of hydrogen gas when the fuel cell is warmed up, FIG. 14 is a block diagram showing the flow of hydrogen gas during MH regeneration, and FIG. 15 is a high output request command output during MH regeneration. It is a block diagram which shows the flow of hydrogen gas when it was made.

  As shown in FIG. 11, the fuel cell system S ″ includes a primary variable regulator CR1 capable of appropriately adjusting the downstream pressure instead of the primary regulator R1 in the first embodiment. The ECU 5 ″ according to this embodiment operates based on a flowchart that is slightly different from the ECU 5 according to the first embodiment. Therefore, in the following description of the operation of the ECU 5 ″, the same steps as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 12, when the ECU 5 ″ receives an ignition switch ON signal, which is a start command for the fuel cell 4 (IGON), the ECU 5 ″ determines whether or not the fuel cell 4 needs to be warmed up in step S1. When it is determined that the warm-up is necessary (Yes), the fuel cell 4 is warmed up by repeating the processes of Steps S3 and S4, as shown in FIG. The hydrogen is supplied from the hydrogen tank 7 to the MH tank 3. Then, after exiting from the warm-up process, the ECU 5 ″ starts the power generation of the fuel cell 4 as shown in FIG. The MH playback mode is slightly different from that of the first embodiment (step S30).

  When shifting to the MH regeneration mode, the ECU 5 ″ determines whether or not a high output request command is output from the user through the processes of steps S7 and S8. In step S7, the FC required pressure is calculated. Then, the secondary variable regulator CR2 is controlled, and the downstream pressure is set to the FC required pressure.

In step S8, when the high output request command is not output (Yes), the ECU 5 ″ controls the primary variable regulator CR1 so that the pressure on the downstream side is higher than the pressure in the MH tank 3. The pressure is set to a pressure that is small and equal to or higher than the pressure on the downstream side of the secondary variable regulator CR2, for example, “[pressure in MH tank 3] − [0.1 MPa]” (step S31). Further, in this step S31, the ECU 5 ″ also performs control for maintaining or opening the MH cutoff valve 33. As a result, as shown in FIG. 14, the pressure on the downstream side of the primary variable regulator CR1 is controlled. As a result, the hydrogen gas is satisfactorily supplied from the MH tank 3 to the fuel cell 4. Here, the ECU 5 "that executes the process of step S31 corresponds to " MH regeneration means ".

As shown in FIG. 12, after step S31, the ECU 5 ″ continues the MH regeneration (steps S7, S8, S31, S10) until it is determined in step S10 that the MH tank 3 has become empty. When a high output request command is output to the fuel cell 4 during such MH regeneration, the ECU 5 ″ determines No in step S8, and controls the primary variable regulator CR1. The pressure on the downstream side is set to a pressure equal to or higher than the FC required pressure, for example, “[FC required pressure] + [0.3 MPa]” (step S32). Further, in this step S32, the ECU 5 ″ also performs control for closing the MH shutoff valve 33. Thereby, high-pressure hydrogen gas is supplied from the high-pressure hydrogen tank 7 only to the fuel cell 4 as shown in FIG. Therefore, it becomes possible to operate the fuel cell 4 with high output, where the ECU 5 ″ that executes the process of step S32 corresponds to “ high output operating means”.

  In step S10, when the ECU 5 ″ determines that the MH tank 3 is empty (Yes), the MH shut-off valve 33 is closed or maintained in the closed state (step S33). Thereby, the MH regeneration process is performed. Is ended (END), and the normal operation of the fuel cell 4 is started.

According to the above, the following effects can be obtained in the third embodiment.
When a high output request command is output to the fuel cell 4 during MH regeneration, the primary variable regulator CR1 and the secondary variable regulator CR2 are appropriately controlled, and the MH cutoff valve 33 is closed, Since the hydrogen gas released from the high-pressure hydrogen tank 7 is not supplied to the MH tank 3 but only to the fuel cell 4, the fuel cell 4 can be operated at a high output.

  Further, in the third embodiment, after the start command for the fuel cell 4 is output, until the normal operation of the fuel cell 4 is started through the warm-up process, the MH regeneration process, and the high-output operation process. Since the intermediate pressure valve 81 may remain open, it is possible to save the electric power necessary for controlling the intermediate pressure valve 81.

In addition, this invention is implemented in various forms, without being limited to each said embodiment.
In each of the above embodiments, the cooling water is circulated between the fuel cell 4 and the MH tank 3, but the present invention is not limited to this, and the cooling water may be circulated also to the radiator. . In this case, it is desirable to provide a bypass for bypassing these in the vicinity of the MH tank and the radiator. By configuring in this manner, for example, during normal operation, the fuel cell can be efficiently cooled by bypassing the MH tank and circulating the cooling water only between the fuel cell and the radiator, Further, at the time of warming up, the fuel cell can be warmed up efficiently by bypassing the radiator and circulating the cooling water only between the fuel cell and the MH tank.

  In each of the above-described embodiments, the transition to the MH regeneration mode is made after the warm-up is completed. That is, for example, when the hydrogen gas stored in the MH tank is used when the fuel cell is stopped, the MH regeneration mode described in each of the above embodiments may be performed at that time.

  In each of the above-described embodiments, the temperature sensor TS1 that directly detects the temperature of the fuel cell 4 and the temperature sensor TS2 that detects the temperature of the cooling water are provided. However, the present invention is not limited to this, and flows into the fuel cell 4, for example. By providing a temperature sensor that detects the temperature of the cooling water that is being performed and a temperature sensor that detects the temperature of the cooling water that is leaving the fuel cell 4, the temperature of the fuel cell 4 and the temperature of the cooling water are measured. May be.

  In the third embodiment, the pressure of the intermediate pressure hydrogen line 8b during MH regeneration is lowered by the primary variable regulator CR1, so that the pressure of the intermediate pressure hydrogen line 8b is lowered in the first and second embodiments. The contributing medium pressure valve 81 may not be provided in the third embodiment. When the intermediate pressure valve 81 is eliminated in this way, a shut-off valve (not shown) in the high-pressure hydrogen tank 7 corresponds to an “open / close valve” in the claims.

It is a lineblock diagram showing the fuel cell system concerning a 1st embodiment. It is a flowchart which shows operation | movement of ECU. It is a block diagram which shows the flow of hydrogen gas at the time of warming up of a fuel cell. It is a block diagram which shows the flow of the hydrogen gas at the time of MH reproduction | regeneration. It is a block diagram which shows the flow of hydrogen gas when a high output request | requirement command is output during MH reproduction | regeneration. It is a block diagram which shows the fuel cell system which concerns on 2nd Embodiment. It is a flowchart which shows operation | movement of ECU. It is a block diagram which shows the flow of hydrogen gas at the time of warming up of a fuel cell. It is a block diagram which shows the flow of the hydrogen gas at the time of MH reproduction | regeneration. It is a block diagram which shows the flow of hydrogen gas when a high output request | requirement command is output during MH reproduction | regeneration. It is a block diagram which shows the fuel cell system which concerns on 3rd Embodiment. It is a flowchart which shows operation | movement of ECU. It is a block diagram which shows the flow of hydrogen gas at the time of warming up of a fuel cell. It is a block diagram which shows the flow of the hydrogen gas at the time of MH reproduction | regeneration. It is a block diagram which shows the flow of hydrogen gas when a high output request | requirement command is output during MH reproduction | regeneration.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 MH tank 31 Hydrogen storage alloy 32 Flow path for MH 33 Shut-off valve for MH 34 Discharge flow path 35 Check valve 4 Fuel cell 5 ECU
6 Compressor 7 High-pressure hydrogen tank (high-pressure hydrogen supply means)
8 Hydrogen gas supply path 81 Medium pressure valve (open / close valve)
9 Circulating flow path 91 Purge hydrogen piping 92 Purge valve CR1 Primary variable regulator CR2 Secondary variable regulator R1 Primary regulator S Fuel cell system

Claims (5)

A fuel cell that generates electricity by reaction of hydrogen gas and oxidant gas;
High-pressure hydrogen supply means for supplying high-pressure hydrogen gas to the fuel cell;
A hydrogen gas supply path connecting the fuel cell and the high-pressure hydrogen supply means;
An on-off valve for switching the communication state of the hydrogen gas supply path;
When a hydrogen storage alloy is incorporated and the fuel cell needs to be warmed up at the time of system startup, an MH tank that warms the fuel cell by storing hydrogen gas in the hydrogen storage alloy ;
A pressure sensor for detecting a tank internal pressure in the MH tank;
A flow path for MH connecting a portion of the hydrogen gas supply path downstream of the on-off valve and the MH tank;
An MH shut-off valve for switching the communication state of the MH channel ;
When the hydrogen gas stored in the MH tank is supplied to the fuel cell after completion of the warm-up of the fuel cell, the on-off valve is closed and the MH shut-off valve is opened, and the hydrogen storage alloy MH regeneration means for regenerating the hydrogen storage alloy by releasing the hydrogen gas stored in
A target hydrogen gas pressure calculating means for calculating a target hydrogen gas pressure of hydrogen gas supplied to the fuel cell based on an output request command externally applied to the fuel cell;
While the hydrogen gas stored in the MH tank is being supplied to the fuel cell by the MH regeneration means, the on- off valve is closed when the tank internal pressure is higher than the target hydrogen gas pressure, and the tank High-power operating means for opening the on-off valve and supplying hydrogen gas from the high-pressure hydrogen supply means to the fuel cell when an internal pressure is not higher than the target hydrogen gas pressure ;
With
The fuel cell system which is characterized a call. The fuel cell system according to claim 1,
The high-power operating means closes the MH shutoff valve when opening the on-off valve. A fuel cell that generates electricity by reaction of hydrogen gas and oxidant gas;
High-pressure hydrogen supply means for supplying high-pressure hydrogen gas to the fuel cell;
A hydrogen gas supply path connecting the fuel cell and the high-pressure hydrogen supply means;
An on-off valve for switching the communication state of the hydrogen gas supply path;
When a hydrogen storage alloy is incorporated and the fuel cell needs to be warmed up at the time of system startup, an MH tank that warms the fuel cell by storing hydrogen gas in the hydrogen storage alloy ;
A pressure sensor for detecting a tank internal pressure in the MH tank;
A flow path for MH connecting the hydrogen gas supply path and the MH tank;
A discharge channel connecting a portion of the hydrogen gas supply channel downstream of the on-off valve and the MH tank;
An MH shut-off valve for switching the communication state of the MH channel;
A check valve that allows only the flow of hydrogen gas from the MH tank to the hydrogen gas supply path in the discharge channel ;
When the hydrogen gas stored in the MH tank is supplied to the fuel cell after the fuel cell has been warmed up , both the on-off valve and the MH shutoff valve are closed, and the hydrogen storage alloy MH regeneration means for regenerating the hydrogen storage alloy by releasing the stored hydrogen gas ;
A target hydrogen gas pressure calculating means for calculating a target hydrogen gas pressure of hydrogen gas supplied to the fuel cell based on an output request command externally applied to the fuel cell;
While the hydrogen gas stored in the MH tank is being supplied to the fuel cell by the MH regeneration means, the on- off valve is closed when the tank internal pressure is higher than the target hydrogen gas pressure, and the tank High-power operating means for opening the on-off valve and supplying hydrogen gas from the high-pressure hydrogen supply means to the fuel cell when an internal pressure is not higher than the target hydrogen gas pressure ;
With
The fuel cell system which is characterized a call. A fuel cell that generates electricity by reaction of hydrogen gas and oxidant gas;
High-pressure hydrogen supply means for supplying high-pressure hydrogen gas to the fuel cell;
A hydrogen gas supply path connecting the fuel cell and the high-pressure hydrogen supply means;
An on-off valve for switching the communication state of the hydrogen gas supply path;
When a hydrogen storage alloy is incorporated and the fuel cell needs to be warmed up at the time of system startup, an MH tank that warms the fuel cell by storing hydrogen gas in the hydrogen storage alloy ;
A pressure sensor for detecting a tank internal pressure in the MH tank;
A flow path for MH connecting a portion of the hydrogen gas supply path downstream of the on-off valve and the MH tank;
An MH shut-off valve for switching the communication state of the MH channel ;
Provided upstream of the connection between the hydrogen gas supply path and the MH flow path, the hydrogen gas released from the high-pressure hydrogen supply means can be depressurized, and the pressure after depressurization can be arbitrarily set and the primary variable regulator,
Provided downstream from the connection between the hydrogen gas supply channel and the MH channel, the hydrogen gas decompressed by the primary variable regulator can be further decompressed, and the pressure after decompression can be arbitrarily set and a secondary variable regulator such,
When the hydrogen gas stored in the MH tank is supplied to the fuel cell after the fuel cell has been warmed up , the pressure on the downstream side of the primary variable regulator is set to the tank while the on-off valve remains open. The hydrogen gas stored in the hydrogen storage alloy is released by setting the pressure lower than the internal pressure and higher than the pressure downstream of the secondary variable regulator and opening the MH shutoff valve. MH regeneration means for regenerating the hydrogen storage alloy ,
A target hydrogen gas pressure calculating means for calculating a target hydrogen gas pressure of hydrogen gas supplied to the fuel cell based on an output request command externally applied to the fuel cell;
While the hydrogen gas stored in the MH tank is being supplied to the fuel cell by the MH regeneration means, the on- off valve is opened when the tank internal pressure is higher than the target hydrogen gas pressure. In addition, the pressure on the downstream side of the primary variable regulator is set to be smaller than the pressure in the tank and equal to or higher than the pressure on the downstream side of the secondary variable regulator, and the pressure in the tank is higher than the target hydrogen gas pressure. If not, the pressure on the downstream side of the primary variable regulator is set to be equal to or higher than the target hydrogen gas pressure while the on-off valve remains open, and the pressure on the downstream side of the secondary variable regulator is set to the target hydrogen gas. High power operating means to set the pressure ;
With
The fuel cell system which is characterized a call. The fuel cell system according to claim 4, wherein
The high-power operating means closes the MH shutoff valve when controlling the primary variable regulator and the secondary variable regulator.

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