JP2005294118A - Fuel cell system and fuel cell vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To warm a fuel cell without installing an electric heater or the like heating a fuel cell main part or without using energy for heating. <P>SOLUTION: An inverter 61 for a compressor motor which is a power control means of a compressor motor 60 for driving a compressor 11 which is one of auxiliaries and an air heating pipe 83 and a hydrogen heating pipe 88 to be heated with the inverter 61 for the compressor motor are installed in a heating device 13. Three-way valves 81, 82, 86, 87 are controlled so that supply passages of air and hydrogen are changed over so as to heat one of them with the heating device 13 and supply to a humidifier 7. The inverter 61 for the compressor motor uses an SiC element 64 using silicon carbide (SiC) which is one of wide gap semiconductors as a switching element for the power control, and heats air or hydrogen by heat generation of the SiC element 64. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell system and a fuel cell vehicle equipped with the fuel cell system.

  In a fuel cell, a fuel gas such as hydrogen and an oxidizing gas containing oxygen are electrochemically reacted through an electrolyte, and electric energy is directly taken out between electrodes provided on both surfaces of the electrolyte. In particular, solid polymer fuel cells using solid polymer electrolytes are attracting attention as power sources for electric vehicles because of their low operating temperature and easy handling. That is, a fuel cell vehicle is equipped with a hydrogen storage device such as a high-pressure hydrogen tank, a liquid hydrogen tank, or a hydrogen storage alloy tank in the vehicle, and reacts by supplying hydrogen supplied therefrom and air containing oxygen to the fuel cell. This is the ultimate clean vehicle that drives the motor connected to the drive wheels with the electric energy extracted from the fuel cell, and the only exhaust material is water.

  By the way, the optimum operating temperature of the polymer electrolyte fuel cell is, for example, 70 to 80 [° C.]. However, when starting the fuel cell system from a low temperature state, the temperature of the fuel cell system rises to an appropriate temperature. If not, the power generation efficiency is lowered, and moisture condenses to block the reaction gas passage, leading to a shutdown.

  In addition, some solid polymer electrolytes do not exhibit hydrogen ion conductivity unless they are sufficiently hydrated. For this reason, moisture exists inside the fuel cell. This moisture freezes when the ambient temperature drops below zero, and it is necessary to thaw the frozen moisture in order to start the fuel cell system.

  FIG. 8 is a main part configuration diagram showing the configuration of the fuel cell system of Conventional Example 1. In FIG. In FIG. 8, this fuel cell system includes a compressor 11 that takes in and compresses air, a cooling device 63 that cools the air compressed by the compressor, an air humidifier 7b, and a high-pressure hydrogen tank 3 that stores hydrogen at high pressure. The hydrogen regulating valve 5 for reducing the hydrogen gas pressure in the high-pressure hydrogen tank 3 to the operating pressure, the ejector 91 for mixing newly supplied hydrogen and the hydrogen electrode off-gas through the hydrogen circulation pipe 90, and the ejector 91 are mixed. A hydrogen humidifier 7a for humidifying the hydrogen gas and the fuel cell main body 2 are provided.

  The outside air is compressed by the compressor 11, cooled by the cooling device 63, and supplied to the air humidifying device 7 b of the humidifying device 7 through the air supply pipe 12. The air that has been humidified and adjusted in temperature by the air humidifier 7 b is supplied to the air electrode of the fuel cell body 2.

  The compressor motor 60 that drives the compressor 11 is driven at a desired rotational speed by an alternating current supplied from the compressor motor inverter 97 via the power supply line 67.

  In a normal operation state, the temperature of the air compressed and discharged by the compressor 11 rises to about 200 [° C.]. For this reason, air is supplied to the humidifier 7 after the air temperature is lowered by the cooling device 63.

  On the other hand, the hydrogen gas in the high-pressure hydrogen tank 3 is depressurized to the operating pressure of the fuel cell by the hydrogen pressure regulating valve 5 and supplied to the ejector 91 through the hydrogen supply pipe 6. The ejector 91, which is a fluid pump, uses the new hydrogen gas flow supplied from the hydrogen supply pipe 6 as a drive source, mixes the new hydrogen gas and the hydrogen electrode off-gas discharged from the fuel cell body 2, and the humidifier 7 To the hydrogen humidifier 7a. The hydrogen humidifier 7 a humidifies the hydrogen gas and adjusts the temperature to supply it to the hydrogen electrode of the fuel cell main body 2.

  When this fuel cell system is started from a low temperature state, the air sucked from the outside is compressed by the compressor 11 and rises in temperature, but is sent to the cooling device 63 where the temperature has not risen, and further heat is taken away. The temperature falls below the temperature (temperature range optimal for power generation). Similarly, the air that has passed through the cooling device 63 passes through the humidifying device 7 whose temperature has not risen, while being further deprived of heat, and is sent to the air inlet of the fuel cell main body 2. For this reason, for a while after startup, the temperature of the air supplied to the fuel cell main body 2 is lower than the optimum temperature for power generation, and power generation may not be possible. Even if power generation is possible, the power generation efficiency is low, and this state continues until the temperature of the fuel cell system reaches an appropriate temperature.

  Further, the hydrogen supplied from the high-pressure hydrogen tank 3 having the same temperature as the outside air is decompressed to the operating condition of the fuel cell by the hydrogen pressure regulating valve 5. At this time, the hydrogen temperature is further lowered by the expansion under reduced pressure and supplied to the hydrogen inlet of the fuel cell main body 2. The temperature of this hydrogen may be lower than the optimum temperature for power generation, and power generation may not be possible. Further, even if power generation is possible, the power generation efficiency is low, and this state continues until the temperature of the fuel cell system reaches an appropriate temperature.

  FIG. 9 is a configuration diagram showing a configuration of a hydrogen supply system in the fuel cell system of Conventional Example 2. In FIG. 9, hydrogen supplied from a hydrogen tank (not shown) is reduced to the operating pressure of the fuel cell by the hydrogen pressure regulating valve 5. The decompressed hydrogen is humidified by the hydrogen humidifier 101 and supplied to the hydrogen electrode of the fuel cell body 2. The hydrogen electrode off-gas discharged from the hydrogen electrode of the fuel cell main body 2 passes through the hydrogen circulation pipe 90 and enters the humidification water tank 21 to separate excess moisture. The hydrogen off-gas from which excess moisture has been separated is sucked out of the humidification water tank by the hydrogen circulation pump 92, and returned to the hydrogen humidifier 101 through the pressure regulating valve 93.

  A pump motor 92 a that drives the hydrogen circulation pump 92 is driven by an alternating current having a frequency corresponding to the rotational speed from the hydrogen circulation pump inverter 94 through the power supply line 67.

  The water separated from the hydrogen off-gas in the humidification water tank 21 is pressurized by the humidification water pump 22 and supplied to the injector 62 through the humidification water pipe 23. The injector 62 injects humidifying water into the hydrogen humidifier 101 to humidify the hydrogen.

  When this fuel cell system is started from a low temperature state, the temperature of hydrogen supplied through the hydrogen pressure regulating valve 5 from a hydrogen tank (not shown), which is approximately the same as the outside air temperature, is further lowered by adiabatic expansion. Even if hydrogen is sent to the hydrogen humidifier 101 in this state, the target humidification amount and temperature are not reached because the temperature is low. Accordingly, there is a possibility that power generation cannot be performed at a temperature lower than the optimum power generation temperature range in the fuel cell main body 2 as it is. Even if power generation is possible, the power generation efficiency is poor, and this state continues until the temperature of the fuel cell system rises to an optimum temperature for power generation.

  For this reason, at the time of starting the fuel cell system, warm-up is performed to raise the fuel cell temperature to a temperature suitable for operation. As such a warming-up method, a technique is known in which a heater is embedded in a gas diffusion layer (GDL) of a fuel cell main body, and the heater is operated at a low temperature startup to warm up (Patent Document 1).

There is also known a technique for providing a heating means for locally heating a part of the power generation surface of the fuel cell, and for warming up the fuel cell with reaction heat generated by the cell heated by the heating means (patent) Reference 2).
Japanese Patent Laid-Open No. 2003-163020 (page 3, FIG. 1) JP 2002-313391 A (page 4, FIG. 2)

  However, in the warming-up method using the conventional heater, a space is required for installing the heater and power consumption for starting the fuel cell system increases. There was a problem that a device was necessary.

  In order to solve the above-mentioned problems, the present invention provides a fuel cell using hydrogen as a fuel, a high-pressure hydrogen container for storing the hydrogen, a compressor for sending air to the fuel cell, and various auxiliary devices used for operating the fuel cell. In the fuel cell system comprising: the power supply means for driving at least one of the auxiliary devices including the compressor or the power control means for controlling the load device of the fuel cell, the supply hydrogen and the supply air The gist is that a heating device for heating at least one of them is provided.

  According to the present invention, the fuel cell system can be warmed up without providing an electric heater or the like for heating the fuel cell, the structure of the fuel cell system is simplified, and power consumption for warming up is achieved. There is an effect that can be reduced.

  Further, in the case of a mobile fuel cell system, there is an effect that the capacity of a power storage device that supplies power for starting the fuel cell system can be reduced.

  Next, embodiments of the present invention will be described in detail with reference to the drawings. In each of the following embodiments, a fuel cell vehicle equipped with the fuel cell system according to the present invention will be described. However, the use of the fuel cell system according to the present invention is not limited to the fuel cell vehicle, but for home use or small scale. It is not limited to the cogeneration system for business establishments.

  FIG. 1 is a system configuration diagram illustrating a configuration example in which a first embodiment of a fuel cell system according to the present invention is mounted on a fuel cell vehicle.

In FIG. 1, a fuel cell system 1 includes a fuel cell body 2 having a hydrogen electrode 2 a and an air electrode 2 b, a high-pressure hydrogen tank 3 that stores hydrogen gas as fuel at high pressure, and supplies hydrogen from the high-pressure hydrogen tank 3. Hydrogen supply valve 4, hydrogen pressure regulating valve 5 for adjusting hydrogen pressure to operating pressure, hydrogen supply piping 6, humidification device 7 having hydrogen humidification device 7a and air humidification device 7b, hydrogen discharge piping 8, and oxidizing agent A compressor 11 for supplying air, an air supply pipe 12, and
The heater 13 provided in the middle of the hydrogen supply pipe 6 and the air supply pipe 12, the air discharge pipe 14, the secondary battery 34, the fuel cell auxiliary machine 35, the drive motor inverter 32, and the vehicle are driven. A drive motor 33 and drive wheels 41 are provided.

  Further, in order to cool a cooling device (not shown) included in the humidifying device 7, a cooling water pump 16, a radiator 17, a radiator fan 18, and a cooling water pipe 19 are provided. The lowered coolant can be supplied to the humidifier 7.

  The fuel cell main body 2 is a fuel cell that includes, for example, a solid polymer electrolyte and generates power using hydrogen as a fuel and air as an oxidant. Hydrogen is adjusted from the high-pressure hydrogen tank 3 through the hydrogen supply valve 4, the hydrogen pressure regulating valve 5, and the hydrogen supply pipe 6 to a temperature and humidity optimal for power generation by the hydrogen humidifier 7 a, and the hydrogen electrode of the fuel cell main body 2. 2a. The air is compressed by the compressor 11, humidified and temperature-adjusted by the air humidifier 7 b through the air supply pipe 12, and supplied to the air electrode 2 b of the fuel cell main body 2.

  The air used for power generation is discharged to the outside from the air discharge pipe 14. The humidifier 7 includes a hydrogen humidifier 7a that humidifies and adjusts the temperature of hydrogen, and an air humidifier 7b that humidifies and adjusts the temperature of air.

  The heating device 13 can include one or both of a hydrogen heating device 13a that heats hydrogen and an air heating device 13b that heats air, or one heating device that switches between air and hydrogen for heating. .

  The electric power generated by the fuel cell body 2 is supplied to the auxiliary machine 35 or the drive motor inverter 32, and surplus power is supplied to the secondary battery 34 and stored while driving the drive motor 33 and auxiliary machines for driving the vehicle. Is done. Further, the regenerative power generated by the deceleration of the vehicle is supplied from the drive motor inverter 32 to the auxiliary machine 35 or the secondary battery 34 and stored.

  When the power generation request for the fuel cell system is insufficient, if the fuel cell main body 2 does not have enough power to be generated, the shortage from the power stored in the secondary battery 34 is used as an assist power source, or the auxiliary machine 35 or the drive motor inverter 32. To supply.

  The fuel cell auxiliary machine 35 includes a compressor 11, a cooling water pump 16, a radiator fan 18, a hydrogen circulation pump (not shown), a cooling water pump for cooling the fuel cell body 2, a radiator fan, and the like.

  FIG. 2 is a configuration diagram for explaining a main part of the first embodiment of the fuel cell system according to the present invention, and shows an embodiment in which the heating device 13 is configured to heat air or hydrogen by switching. In addition, the same code | symbol is provided to the same component as the system block diagram shown in FIG.

  In the conventional example 1 shown in FIG. 8, the temperature of air and hydrogen supplied to the fuel cell main body at the time of start-up from a low temperature is low, and there is a possibility that power generation cannot be performed. However, there was a problem that it continued until the warm-up of the fuel cell system was completed. In order to solve this problem, as described in Patent Document 1 or 2, when an electric heater for heating the fuel cell main body is provided, the structure of the fuel cell main body becomes complicated and the power consumption for startup increases. There was a problem of doing. The present embodiment solves this problem and provides a fuel cell system that can save power consumption for warm-up at startup without complicating the structure of the fuel cell main body.

  2, the fuel cell system of this embodiment includes a compressor 11 that takes in and compresses air, a cooling device 63 that cools the air compressed by the compressor, a high-pressure hydrogen tank 3 that stores hydrogen at high pressure, and a high-pressure hydrogen. A hydrogen pressure control valve 5 for reducing the hydrogen gas pressure in the tank 3 to the operating pressure, a heating device 13 for heating the air that has passed through the cooling device 63 or the hydrogen pressure reduced by the hydrogen pressure control valve 5, an air humidifier 7b, The fuel cell body 2 includes an ejector 91 that mixes the hydrogen supplied to the gas and hydrogen electrode off-gas through the hydrogen circulation pipe 90, a hydrogen humidifier 7 a that humidifies the hydrogen gas mixed by the ejector 91.

  Compared to the conventional example 1 shown in FIG. 8, the elements added in the present embodiment shown in FIG. 2 are the heating device 13 for heating air or hydrogen, the three-way valves 81, 82, 86, 87, and the air bypass pipe. 84 and a hydrogen bypass pipe 89.

  The heating device 13 includes a compressor motor inverter 61 that is a power control means of a compressor motor 60 that drives the compressor 11 that is one of the auxiliary machines, an air heating pipe 83 that is heated by the compressor motor inverter 61, and hydrogen. A heating tube 88 is arranged. The compressor motor inverter 61 supplies driving AC power to the compressor motor 60 via a compressor motor power supply line 67. The rotational speed of the compressor 11 is controlled by the frequency of the alternating current generated by the compressor motor inverter 61.

  For the compressor motor inverter 61, a SiC element 64 using silicon carbide (SiC), which is a kind of wide gap semiconductor, is used as a switching element for power control.

  As a switching element for power control, a bipolar transistor, an insulated gate field effect transistor (MIS-FET), an insulated gate bipolar transistor (IGBT), various thyristors, and the like can be used.

  The wide gap semiconductor material is not limited to SiC, and is a switching element using any of a diamond structure carbon, a II-VI group compound such as ZnS, ZnSe, or a III-V group compound such as GaP, GaN, BP, BN. May be formed. Since these wide gap semiconductors have a wider band gap (forbidden band width) than silicon (Si) semiconductor elements and can operate up to high temperatures, when using this heat as a heat source for a heating device, a radiator Can be reduced in size or omitted, and is suitable for power control for a moving body.

  The SiC element 64, which is a switching element of the compressor motor inverter 61, is arranged in contact with the air heating pipe 83 and the hydrogen heating pipe 88, and the heat generated by the SiC element 64 is transmitted to them to heat the air or hydrogen. It can be done.

  The three-way valves 81 and 82 are valves that switch the air path between the cooling device 63 and the air humidifying device 7b between the air heating pipe 83 and the air bypass pipe 84. Similarly, the three-way valves 86 and 87 are valves for switching the hydrogen path between the hydrogen pressure regulating valve 5 and the hydrogen humidifier 7a between the hydrogen heating pipe 88 and the hydrogen bypass pipe 89.

  When the air is heated by the heating device 13, the three-way valves 81 and 82 in the air path are switched to the air heating pipe 83 side of the heating device 13, respectively, and the three-way valves 86 and 87 in the hydrogen path are respectively in the hydrogen bypass piping 89 side. Switch to.

  On the contrary, when hydrogen is heated by the heating device 13, the three-way valves 81 and 82 in the air path are switched to the air bypass pipe 84 side, and the three-way valves 86 and 87 in the hydrogen path are respectively switched to the heating device 13. Switch to the hydrogen heating tube 88 side.

  In FIG. 2, the outside air is compressed by the compressor 11, cooled by the cooling device 63, and supplied to the air humidifying device 7 b of the humidifying device 7 through the air supply pipe 12. The air that has been humidified and adjusted in temperature by the air humidifier 7 b is supplied to the air electrode of the fuel cell body 2.

  The compressor motor 60 that drives the compressor 11 is driven at a desired rotational speed by an alternating current supplied from the compressor motor inverter 97 via the power supply line 67.

  In a normal operation state, the temperature of the air compressed and discharged by the compressor 11 rises to about 200 [° C.]. For this reason, air is supplied to the humidifier 7 after the air temperature is lowered by the cooling device 63.

  On the other hand, the hydrogen gas in the high-pressure hydrogen tank 3 is depressurized to the operating pressure of the fuel cell by the hydrogen pressure regulating valve 5 and supplied to the ejector 91 through the hydrogen supply pipe 6. The ejector 91, which is a fluid pump, uses the new hydrogen gas flow supplied from the hydrogen supply pipe 6 as a drive source, mixes the new hydrogen gas and the hydrogen electrode off-gas discharged from the fuel cell body 2, and the humidifier 7 To the hydrogen humidifier 7a. The hydrogen humidifier 7 a humidifies the hydrogen gas and adjusts the temperature to supply it to the hydrogen electrode of the fuel cell main body 2.

  In FIG. 2, when the fuel cell system is warmed up, the compressor 11 is driven to supply air, and the driving load is positively increased in order to promote the heat generation of the SiC element 64 of the compressor motor inverter 61. By transferring the heat of the SiC element 64 to the air heating pipe 83 and the hydrogen heating pipe 88, the fuel cell inlet temperature of air and hydrogen can reach the temperature range optimal for power generation in a relatively short time. By reaching the fuel cell inlet temperature to a temperature range optimal for power generation, the warm-up time of the entire fuel cell system is shortened.

  Further, in the fuel cell system of FIG. 2, it is preferable that the temperature of air and hydrogen be close to each other so that oxygen in the air and hydrogen as a fuel are optimally subjected to chemical reaction and power generation inside the fuel cell. For this reason, it is necessary to adjust the fuel cell main body 2 to approach the same temperature, and even if there is a temperature difference between hydrogen and air at the inlets of the hydrogen humidifier 7a and the air humidifier 7b, the humidification is performed. The temperature can be adjusted with the device. However, since the humidifier has a limit of the temperature adjustment range unique to the apparatus, it is necessary to adjust the temperature difference between the hydrogen temperature T2 and the air temperature T4 at the inlet of the humidifier.

  For this reason, an air bypass pipe 84 and three-way valves 81 and 82 are provided between the cooling device 63 of the air supply system and the air humidifier 7b, and a hydrogen bypass between the hydrogen pressure regulating valve 5 of the hydrogen supply system and the hydrogen humidifier 7a. A pipe 89 and a three-way valve 87 are set. Then, the three-way valves 81, 82, 86, and 87 are switched depending on the necessity of heating, and the temperature difference between the air and hydrogen up to the humidifier inlet is controlled to be small. Thereby, further shortening of the warm-up operation time and steady operation can be performed stably and optimally.

  In addition, when the outside air temperature is particularly low and is equal to or lower than a predetermined temperature (for example, 0 [° C.]), the SiC motor element 61 is operated at a low-efficiency operating point in which the efficiency is lower than that during normal operation. 64 is positively heated, and a larger amount of heat is supplied from the heating device 13 to the supply air or supply hydrogen, so that the warm-up time can be shortened. As a method of setting the low-efficiency operating point, there is a method of increasing the power consumption at the time of switching by delaying the rise time and fall time of the signal for driving the SiC element 64.

  When the fuel cell temperature exceeds a predetermined temperature (for example, 80 [° C.]) and the warm-up is completed, the operation of the compressor inverter 61 is continuously performed from the low-efficiency operation point to the operation point during normal operation. Alternatively, the temperature of air or hydrogen can be optimally adjusted by changing the heat generation amount per unit time of the SiC element 64 by changing it stepwise.

  In the first embodiment, the configuration in which air or hydrogen is heated using the heat generated by the inverter for the compressor motor that drives the compressor that supplies air to the fuel cell has been described. In the second embodiment, the heat generated by the inverter for the hydrogen circulation pump is generated. The case where hydrogen is humidified using this will be described.

  FIG. 3 is a configuration diagram for explaining a main configuration of the fuel cell system according to the present embodiment. In FIG. 3, hydrogen supplied from a hydrogen tank (not shown) is reduced to the operating pressure of the fuel cell by the hydrogen pressure regulating valve 5. The decompressed hydrogen is humidified by the hydrogen humidifier 101 and supplied to the hydrogen electrode of the fuel cell body 2. The hydrogen electrode off-gas discharged from the hydrogen electrode of the fuel cell main body 2 passes through the hydrogen circulation pipe 90 and enters the humidification water tank 21 to separate excess moisture. The hydrogen off-gas from which excess moisture has been separated is sucked out of the humidification water tank by the hydrogen circulation pump 92, and returned to the hydrogen humidifier 101 through the pressure regulating valve 93.

  A pump motor 92 a that drives the hydrogen circulation pump 92 is driven by an alternating current having a frequency corresponding to the rotational speed from the hydrogen circulation pump inverter 94 through the power supply line 67.

  The water separated from the hydrogen off-gas in the humidification water tank 21 is pressurized by the humidification water pump 22 and supplied to the injector 62 through the humidification water pipe 23. The injector 62 injects humidifying water into the hydrogen humidifier 101 to humidify the hydrogen.

  The difference between this embodiment of FIG. 3 and the conventional example 2 shown in FIG. 9 is that in this embodiment, the hydrogen circulation pump inverter 94 is arranged in the hydrogen humidifier 7a, and the switching element of the hydrogen circulation pump inverter 94 is used. A certain SiC element 64 heats hydrogen or water jetted from the injector 62 inside the hydrogen humidifier 7b. According to the present embodiment, hydrogen can be humidified using heat generated from the power control means of the auxiliary machine without providing the hydrogen humidifier 7a with a heating means such as an electric heater that consumes energy. Similarly, it is obvious that the heat generated by the power control means of the auxiliary machine can be applied to the air humidifier.

  In the present embodiment, the fuel cell main body 2 can be warmed up using the heat generated by the inverter for the hydrogen circulation pump. When the fuel cell system is started at a low temperature, in the conventional example 2 shown in FIG. 9, the hydrogen supplied through the hydrogen pressure regulating valve 5 from the hydrogen tank outside the figure, which is the same temperature as the outside air temperature, is further heated by adiabatic expansion. Go down. Even if hydrogen is sent to the hydrogen humidifier 101 in this state, the target humidification amount and temperature are not reached because the temperature is low. Accordingly, there is a possibility that power generation cannot be performed at a temperature lower than the optimum power generation temperature range in the fuel cell main body 2 as it is. In addition, even if power generation is possible, power generation efficiency is poor, and this state continues until the fuel cell system temperature rises to an optimum temperature for power generation.

  In the present embodiment, in order to solve this problem, in the fuel cell system including the hydrogen circulation pump for returning the hydrogen electrode off-gas discharged from the fuel cell main body 2 to the humidifier, the hydrogen circulation pump inverter 94 is connected to the hydrogen circulation pump. Installed in the humidifier 7a, drives the hydrogen circulation pump 92 to circulate hydrogen between the hydrogen humidifier 7a and the fuel cell main body 2, and uses the heat generated by the inverter 94 for the hydrogen circulation pump to generate the hydrogen humidifier 7a. By heating the hydrogen, the fuel cell system is warmed up.

  Further, in order to increase the calorific value of the SiC element 64, the hydrogen temperature inside the hydrogen humidifier 7a can be further increased by positively increasing the load of the hydrogen circulation pump 92, and the hydrogen fuel cell inlet temperature. By reaching the temperature range optimum for power generation, the warm-up time of the entire fuel cell system is shortened.

  Further, by arranging the humidification water pipe 23 for supplying humidification water to the hydrogen humidification device 7 a close to the SiC element 64, the humidification water can receive the heat of the SiC element 64 and raise the temperature. Then, the temperature of the humidified water is injected into the hydrogen humidifier 7a by the injector 62, whereby the hydrogen temperature can be further increased, the warm-up time of the entire fuel cell system is shortened, and stable steady state You can drive.

  FIG. 4 is a main part configuration diagram of the fuel cell system of Example 3, and shows an air supply system of the fuel cell. In FIG. 4, the air supply system of the third embodiment includes a compressor 11 that is driven by a compressor motor 60 to compress air, an air supply pipe 12, an air heating device 13 b that heats the air supply pipe 12, and a cooling device 63. And an air humidifier 7b.

  The air heating device 13 b includes a compressor motor inverter 61 that supplies driving power to the compressor motor 60 as a heat source, and the driving AC is supplied from the compressor motor inverter 61 to the compressor motor 60 via the compressor motor power supply line 67. It is designed to supply power. The rotational speed of the compressor 11 is controlled by the frequency of the alternating current generated by the compressor motor inverter 61.

  The compressor motor inverter 61 is arranged so as to be in direct contact with the air supply pipe 12 or indirectly through a heat exchange member having an appropriate heat exchange fin (not shown), and the SiC element of the compressor motor inverter 61 The heat generated at 64 is transmitted to the air passing through the inside of the air supply pipe 12.

  The compressor motor inverter 61 uses a SiC element 64 using silicon carbide (SiC), which is a kind of wide gap semiconductor, as a switching element for power control.

  As a switching element for power control, a bipolar transistor, an insulated gate field effect transistor (MIS-FET), an insulated gate bipolar transistor (IGBT), various thyristors, and the like can be used.

  The wide gap semiconductor material is not limited to SiC, and is a switching element using any of a diamond structure carbon, a II-VI group compound such as ZnS, ZnSe, or a III-V group compound such as GaP, GaN, BP, BN. May be formed. Since these wide gap semiconductors have a wider band gap (forbidden band width) than silicon (Si) semiconductor elements and can operate up to high temperatures, when using this heat as a heat source for a heating device, a radiator Can be reduced in size or omitted, and is suitable for power control for a moving body.

  In a steady state in which a sufficient time has elapsed since the start of the start of the fuel cell main body 2, the compressor 11 itself is also warmed by the compression heat of the air, and the temperature of the air discharged from the compressor 11 becomes about 200 [° C.]. However, since the temperature of the air supplied to the fuel cell main body 2 is preferably about 80 [° C.], the temperature of the air is adjusted to the vicinity of this temperature by the cooling device 63. The temperature-adjusted air is humidified by the air humidifier 7 b and supplied to the fuel cell body 2.

  Next, the state immediately after starting this fuel cell system will be described. When the fuel cell system is started when the outside air temperature is low, the temperature of the air compressed by the compressor 11 tends to rise, but most of the temperature rise is spent for the temperature rise of the compressor itself, which has a low temperature and a large heat capacity. It takes time for the temperature of the air discharged from the compressor 11 to rise.

  On the other hand, since the compressor 11 is operated at the same time as the start of the fuel cell to supply air to the fuel cell, the compressor motor inverter 61 that supplies power to the compressor motor 60 is also operated at the same time as the start. For this reason, simultaneously with the start-up, the SiC 64 element which is the switching element of the compressor motor inverter 61 starts to generate heat, and the temperature rises rapidly. The air heating device 13b heats the air by the heat of the SiC element 64, and sends the air to the air humidifying device 7b through the cooling device 63.

  In addition, when the outside air temperature is particularly low and is equal to or lower than a predetermined temperature (for example, 0 [° C.]), the SiC motor element 61 is operated at a low-efficiency operating point in which the efficiency is lower than that during normal operation. 64 can be positively heated, and a larger amount of heat can be applied to the supply air from the air heating device 13b to shorten the warm-up time. As a method of setting the low-efficiency operating point, there is a method of increasing the power consumption at the time of switching by delaying the rise time and fall time of the signal for driving the SiC element 64.

  When the fuel cell temperature exceeds a predetermined temperature (for example, 80 [° C.]) and the warm-up is completed, the operation of the compressor inverter 61 is continuously performed from the low-efficiency operation point to the operation point during normal operation. Alternatively, the temperature of air or hydrogen can be optimally adjusted by changing the heat generation amount per unit time of the SiC element 64 by changing it stepwise.

  Since the compressor 11 is always operated during the operation of the fuel cell main body 2, heat generation of the SiC element 64 used as a switching element of the compressor motor inverter 61 can be always obtained. By using the heat generated by the SiC element 64 for heating the supplied air, it is possible to heat the air and shorten the warm-up time without separately providing a heating device such as an electric heater.

  In this embodiment, SiC is used as the switching element of the compressor motor inverter. However, the upper limit of the junction temperature of the Si semiconductor used in the conventional switching element is about 150 [° C.]. The air rises to about 200 ° C by the compression heat of the compressor, but SiC has the feature that the junction temperature can be used up to about 300 [° C], so it can be operated at a higher temperature than the Si element. And when it is used as a heat source of a heating device, the thermal efficiency of heating air can be improved.

  FIG. 5 is a main part configuration diagram of the fuel cell system of Example 4, and shows an air supply system of the fuel cell. In FIG. 5, the air supply system of the fourth embodiment includes a compressor 11 driven by a compressor motor 60 to compress air, an air supply pipe 12, an air heating device 13 b that heats the air supply pipe 12, and a cooling device 63. An air humidifier 7b, a refrigerant pump 72 that circulates a refrigerant that cools the heat of the compressor motor inverter 61, a radiator 71 such as a radiator that discharges the heat of the refrigerant outside the system, and a refrigerant pipe 73. ing.

  The difference between the present embodiment and the third embodiment shown in FIG. 4 is that, in this embodiment, as a cooling means for releasing the heat generated by the compressor motor inverter after the warm-up, the heat radiating device 71 and the refrigerant That is, a pump 72, a heat radiating device 71, a compressor motor inverter 61, and a refrigerant pipe 73 for connecting the refrigerant pump 72 to each other are provided. Since the other configuration is the same as that of the third embodiment shown in FIG. 4, the same components are assigned the same reference numerals and redundant description is omitted.

  According to the present embodiment, when the cooling means is provided in the compressor motor inverter 61 and the warming-up is completed and heating of the supply air becomes unnecessary, the cooling of the SiC element 64 as the switching element is performed. In addition, the SiC element 64 can be sufficiently cooled even if the capacity of the heat dissipation device 71 and the refrigerant pump 72 is small.

  FIG. 6 is a configuration diagram for explaining a configuration of main parts of a fifth embodiment of the fuel cell system according to the present invention. In the configuration as in the third embodiment shown in FIG. 4, when time elapses from the start of the fuel cell body 2 and the fuel cell body 2 itself warms up, the compression heat of the air generated from the compressor and the inverter of the power control means Since it is necessary to cool the air heating by the SiC element, the cooling capacity of the cooling device 63 needs to be increased.

  In this embodiment, the fuel cell is warmed up by a heating device that heats the air supplied to the fuel cell using the heat generated by the power control means for driving the auxiliary machine, and after the warm-up is completed, the heating device is bypassed. It is characterized in that it is unnecessary to increase the cooling capacity of the cooling device by supplying the air to the fuel cell.

  6, the air supply system of the fuel cell system of Example 6 includes a compressor 11 that is driven by a compressor motor 60 to compress air, an air heating device 13 b that heats the air compressed by the compressor 11, and a three-way valve 81. , 82, an air bypass pipe 84 that bypasses the air heating device 13b, a cooling device 63 that cools the air, an air humidifying device 7b that humidifies the air, and the fuel cell main body 2.

  The three-way valves 81 and 82 are arranged to switch the air path between the compressor 11 and the cooling device 63 between the air heating device 13 b and the air bypass pipe 84.

  The air heating device 13 b includes a compressor motor inverter 61 that supplies driving power to the compressor motor 60 as a heat source, and the driving AC is supplied from the compressor motor inverter 61 to the compressor motor 60 via the compressor motor power supply line 67. It is designed to supply power. The rotational speed of the compressor 11 is controlled by the frequency of the alternating current generated by the compressor motor inverter 61.

  The compressor motor inverter 61 is arranged so as to contact the air heating pipe 83 arranged inside the air heating device 13b directly or indirectly through a heat exchange member provided with an appropriate heat exchange fin (not shown). The heat generated in the compressor motor inverter 61 is transmitted to the air passing through the air supply pipe 12.

  The compressor motor inverter 61 uses a SiC element 64 using silicon carbide (SiC), which is a kind of wide gap semiconductor, as a switching element for power control.

  As a switching element for power control, a bipolar transistor, an insulated gate field effect transistor (MIS-FET), an insulated gate bipolar transistor (IGBT), various thyristors, and the like can be used.

  The wide gap semiconductor material is not limited to SiC, and is a switching element using any of a diamond structure carbon, a II-VI group compound such as ZnS, ZnSe, or a III-V group compound such as GaP, GaN, BP, BN. May be formed. Since these wide gap semiconductors have a wider band gap (forbidden band width) than silicon (Si) semiconductor elements and can operate up to high temperatures, when using this heat as a heat source for a heating device, a radiator Can be reduced in size or omitted, and is suitable for power control for a moving body.

  When starting the fuel cell system from a low temperature, the three-way valves 81 and 82 are switched to the air heating pipe 83 side. When the compressor 11 is driven in this state, the compressed air is heated by the air heating pipe 83 passing through the inside of the air heating device 13b by receiving heat from the SiC element 64 which is a switching element of the compressor motor inverter 61. Since the air thus heated is supplied to the fuel cell, warm-up of the fuel cell main body 2 is promoted.

  When the temperature of the fuel cell body 2 itself rises and the warm-up is completed, as described above, the SiC element 64 can be operated up to 300 [° C.] without being cooled. By switching 81 and 82 to the air bypass pipe 84 side, the air bypassing the air heating device 13b can be supplied to the cooling device 63. For this reason, after the warm-up is completed, the supply air can be supplied to the cooling device 63 without being heated by the air heating device 13b, and an increase in the cooling capacity of the cooling device 63 becomes unnecessary.

  FIG. 7 is a configuration diagram for explaining a configuration of main parts of a sixth embodiment of the fuel cell system according to the present invention. In this embodiment, a case where a switching element used for an inverter as a power control means of an auxiliary machine is not a wide-gap semiconductor material but a generally popular, easily available, and inexpensive Si element is used will be described.

  In FIG. 7, the air supply system of the fuel cell system according to the sixth embodiment includes a compressor 11 that is driven by a compressor motor 60 to compress air, a cooling device 63 that cools air compressed by the compressor 11, and a cooling device 63. An air humidifier 7b that humidifies the cooled air, three-way valves 81 and 82, an air heater 13b, an air bypass pipe 84, and the fuel cell main body 2 are provided.

  The three-way valves 81 and 82 are arranged to switch the air path between the air humidifier 7b and the air electrode of the fuel cell main body 2 between the air heater 13b and the air bypass pipe 84. .

  The air heating device 13 b includes a compressor motor inverter 61 that supplies driving power to the compressor motor 60 as a heat source. It is designed to supply power. The rotational speed of the compressor 11 is controlled by the frequency of the alternating current generated by the compressor motor inverter 61.

  The compressor motor inverter 61 is arranged so as to contact the air heating pipe 83 arranged inside the air heating device 13b directly or indirectly through a heat exchange member provided with an appropriate heat exchange fin (not shown). The heat generated in the compressor motor inverter 61 is transmitted to the air passing through the air supply pipe 12.

  The compressor motor inverter 61 uses a Si element 85 using silicon (Si) as a semiconductor material as a switching element for power control. When the Si element 85 is used as the switching element, the upper limit of the junction temperature is about 150 [° C.], so the air compressed by the compression heat of the compressor 11 after the warm-up is about 200 [° C.]. However, since the temperature is adjusted to about 80 [° C.] suitable for supplying the fuel cell by the cooling device 63 in advance, the warm-up time is shortened as in the case of the SiC element described in the other embodiments. An effect can be obtained.

  According to the present embodiment having the above-described configuration, the warm-up time can be shortened without separately adding a heat source such as an electric heater to the fuel cell main body 2.

  In addition, each Example described above was described in order to make an understanding of this invention easy, Comprising: It is not the thing described in order to limit this invention. Accordingly, each element disclosed in the above embodiment is intended to include all design changes belonging to the technical scope of the present invention.

  For example, in each of the above embodiments, the heat generated from the switching element of the inverter, which is the power control means of the compressor or hydrogen circulation pump as an auxiliary machine, is used as the heat source of the heating device or the humidifying device. The heat generated by the switching element of the drive motor inverter that controls the means and the drive motor that is the load device of the fuel cell may be used.

  Further, when the auxiliary machine or the load device is a device using DC power, a DC / DC converter or chopper can be used as a power control means, and the heat generated by these power control means can be used as a heat source.

1 is a system configuration diagram illustrating a configuration of a fuel cell system according to the present invention. 1 is a main part configuration diagram of a fuel cell system of Example 1. FIG. FIG. 3 is a configuration diagram of a main part of a fuel cell system according to a second embodiment. FIG. 5 is a configuration diagram of a main part of a fuel cell system according to a third embodiment. FIG. 6 is a configuration diagram of a main part of a fuel cell system according to a fourth embodiment. FIG. 10 is a main part configuration diagram of a fuel cell system of Example 5. FIG. 10 is a main part configuration diagram of a fuel cell system of Example 6. It is a principal part block diagram of the prior art example 1. FIG. It is a principal part block diagram of the prior art example 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell system 2 ... Fuel cell main body 3 ... High pressure hydrogen tank 4 ... Hydrogen supply valve 5 ... Hydrogen pressure regulating valve 6 ... Hydrogen supply piping 7 ... Humidification device 8 ... Hydrogen discharge piping 11 ... Compressor 12 ... Air supply piping 13 ... Heating Device 14 ... Air discharge pipe 16 ... Cooling water pump 17 ... Radiator 18 ... Radiator fan 19 ... Cooling water pipe 32 ... Drive motor inverter 33 ... Drive motor 34 ... Secondary battery 35 ... Auxiliary machine 41 ... Drive wheel

Claims (11)

In a fuel cell system comprising a fuel cell using hydrogen as a fuel, a hydrogen storage container for storing the hydrogen, a compressor for sending air to the fuel cell, and various auxiliary devices for operating the fuel cell,
A heating device that heats at least one of the supplied hydrogen and the supplied air based on heat generated by power control means for driving at least one of the auxiliary devices including the compressor or power control means for controlling a load device of the fuel cell; A fuel cell system comprising:   2. The fuel cell system according to claim 1, wherein, when the outside air temperature is lower than a predetermined temperature, the power control means is positively heated to shorten the warm-up time of the fuel cell.   2. The temperature of air or hydrogen is adjusted by controlling the heat generation amount per unit time of the power control means when the temperature of the fuel cell exceeds a predetermined temperature and the warm-up is completed. The fuel cell system according to claim 2. The heating device can selectively heat air or hydrogen,
2. The temperature of air or hydrogen is preferentially adjusted by switching the path of air or hydrogen to pass through the heating means when the warm-up is completed and the fuel cell system is warmed. The fuel cell system described.   The fuel cell system according to any one of claims 1 to 4, further comprising a bypass pipe that bypasses the heating device and supplies air or hydrogen to the fuel cell without heating. A humidifier for humidifying at least one of air and hydrogen fed to the fuel cell;
The fuel cell system according to claim 1, wherein humidification is performed in the humidifier using heat generated by the power control unit.   2. The fuel cell according to claim 1, wherein the power control means is a DC / AC inverter that supplies an alternating current to an auxiliary machine or a load device, and heat generated by a switching element of the DC / AC inverter is used as the heat source. system.   The power control means is a DC / DC converter or chopper that controls a direct current supplied to an auxiliary machine or a load device, and heat generated by the DC / DC converter or the switching element of the chopper is used as a heat source of the heating device. The fuel cell system according to claim 1, wherein:   9. The fuel cell system according to claim 7, wherein the switching element is a wide gap semiconductor element using a wide gap semiconductor material.   10. The fuel cell system according to claim 9, wherein the wide gap semiconductor material is any one of silicon carbide (SiC), diamond-structured carbon, II-VI group compound, and III-V group compound.   11. A fuel cell vehicle equipped with the fuel cell system according to claim 1, wherein the load device is a drive motor that drives the vehicle.

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