JP2010073461A - Fuel cell system - Google Patents

Abstract

A fuel cell system including a low-cost cooling device that cools a motor for driving a compressor with a simple structure.
A fuel cell that generates power by supplying a fuel gas to a fuel electrode and supplying an oxidant gas to an oxidant electrode; a supply flow path for flowing an oxidant gas supplied to the fuel cell; A discharge flow path 12 through which the oxidant gas off-gas discharged from the fuel cell 2 flows, a compressor 14 that is provided in the supply flow path 11 and pumps the oxidant gas to the fuel cell 2, and a motor M1 that drives the compressor 14 The cooling means 17 for cooling the oxidant gas compressed by the compressor 14 and the controller 7 for controlling the flow of the oxidant gas supplied to the fuel cell 2 by the compressor 14 are provided, and the oxidant gas off-gas is compressed. It is introduced into the motor M1 that drives the machine 14 to cool the motor M1.
[Selection] Figure 1

Description

  The present invention relates to cooling of a fuel cell system.

  In a fuel cell, hydrogen containing hydrogen and oxygen containing oxygen as the oxidant are used. Hydrogen is separated into hydrogen ions and electrons by the action of the catalyst on the fuel side electrode, and the separated electrons move through an external load to generate power. As taken out. Hydrogen ions move to the oxidant electrode through the electrolyte membrane, and water is generated by combining hydrogen ions, electrons that have traveled around the external load, and oxygen by the action of the catalyst on the oxidant side electrode.

In such a fuel cell system, an air compressor is used to supply air as an oxidant gas to the fuel cell system, and the air compressor uses necessary air based on the amount of fuel gas supplied or the amount of power generation. The amount is calculated, and the rotational speed of the motor that drives the air compressor is controlled so that the required air flow rate is supplied. Then, as described in Patent Document 1, air-cooled heat exchange in which air that has been pressurized to a predetermined operating pressure by an air compressor and heated to a high temperature is exchanged with air discharged from the fuel cell (oxidant gas off-gas). It is known that the fuel cell is cooled to an appropriate temperature via a water-cooled heat exchanger using water as a refrigerant and supplied to the air electrode (oxidant electrode) of the fuel cell. Also, in order to cool the motor that is hot for driving the compressor, water is circulated from the water-cooled heat exchanger, or a water circulation path is separately constructed to introduce water into the motor and cool it. Is generally known.
JP 2004-296339 A

  However, in the prior art described in Patent Document 1, two air exchangers, air-cooled and water-cooled, are provided in order to compensate for the lack of air cooling capability required during high-load operation. In particular, water-cooled heat exchangers require a complicated system configuration and control in spite of excessive cooling capacity during normal operation, which is much more frequently used than during high-load operation. There is. In addition, a water-cooled cooling device that is generally used to cool a compressor driving motor also requires a radiator, piping, a cooling water pump, and the like, which increases the cost.

  An object of the present invention is to provide a fuel cell system having a simple structure and a low-cost cooling device that cools a motor for driving a compressor.

  In order to solve the above-described problem, the structural feature of the invention according to claim 1 is that a fuel cell that generates power by supplying fuel gas to the fuel electrode and supplying oxidant gas to the oxidant electrode, and the fuel A supply channel through which the oxidant gas supplied to the battery flows, a discharge channel through which the oxidant gas off-gas discharged from the fuel cell flows, and the supply channel, and the oxidant gas is supplied to the fuel cell. A compressor for pumping, a motor for driving the compressor, a cooling means for cooling the oxidant gas compressed by the compressor, and a flow of the oxidant gas supplied to the fuel cell by the compressor A control device that controls the oxidant gas, and the oxidant gas off-gas is introduced into the motor that drives the compressor to cool the motor.

  According to a second aspect of the present invention, in the fuel cell system according to the first aspect, the supply flow path further includes a temperature sensor that detects a temperature of the oxidant gas cooled by the cooling means. When the oxidant gas temperature detected by the temperature sensor exceeds a predetermined temperature, the control device controls the rotation of the motor that drives the compressor according to the detected temperature to compress the compression Adjusting the temperature of the oxidant gas in the machine.

  The structural feature of the invention according to claim 3 is the fuel cell system according to claim 1 or 2, wherein the cooling means is a heat exchanger that exchanges heat with the oxidant gas off-gas, The oxidant gas off-gas heat-exchanged by the heat exchanger is introduced into the motor that drives the compressor to cool the motor.

  According to a fourth aspect of the present invention, in the fuel cell system according to the third aspect, a cooler for cooling the oxidant gas off-gas heat-exchanged by the heat exchanger is provided in the discharge channel. It is to prepare.

  In the invention according to claim 1 configured as described above, since the oxidant gas off-gas is introduced into the motor that drives the compressor and heat exchange is performed to cool the motor, it is not necessary to provide a water-cooled cooling device. This eliminates the need for pipes, radiators, cooling water pumps, control systems, and the like that were necessary to provide a water-cooled cooling device, thereby reducing costs and reducing the size of the system. it can.

  In the invention according to claim 2 configured as described above, a temperature sensor for detecting the temperature of the oxidant gas cooled by the cooling means is provided in the supply flow path, and the oxidant gas temperature detected by the temperature sensor is When the temperature is higher than a predetermined temperature (for example, 100 ° C.), the rotation of the motor that drives the compressor is controlled according to the detected temperature, and control for suppressing the temperature increase of the oxidant gas is performed. As a result, even if there is no water-cooling type cooling device, it is possible to prevent the fuel cell from being supplied with a high-temperature oxidant gas exceeding an appropriate temperature, thereby maintaining the power generation efficiency and improving the reliability.

  In the invention according to claim 3 configured as described above, the oxidant gas is heat-exchanged by the oxidant gas off-gas and the heat exchanger as a cooling means, and cooled to an appropriate temperature. Then, the oxidant gas off-gas that has been heat-exchanged with the oxidant gas and increased in temperature is introduced into a motor that drives the compressor, and heat is exchanged to cool the motor. Therefore, it is not necessary to provide a water-cooled cooling device. This eliminates the need for pipes, radiators, cooling water pumps, control systems, and the like necessary to provide a water-cooled cooling device for cooling the oxidant gas and motor for driving the compressor. The cost can be reduced and the system can be further downsized.

  In the invention which concerns on Claim 4 comprised as mentioned above, in order to cool the oxidizing gas off-gas heat-exchanged by a heat exchanger, a cooler is provided on a discharge flow path. As a result, the oxidant gas off-gas is further cooled down before being introduced into the heat exchanger, so that the oxidant gas and the motor for driving the compressor can be reliably cooled, and the reliability is improved.

  Hereinafter, a first embodiment of a fuel cell system according to the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a fuel cell system 1. The fuel cell system 1 of the present embodiment can be applied to vehicles such as fuel cell vehicles (FCHV), electric vehicles, and hybrid vehicles, but of course, not only vehicles but also various moving bodies (for example, ships, airplanes, robots, etc.) and stationary devices. It is also applicable to mold power supplies.

  The fuel cell system 1 includes a fuel cell 2, an oxidant gas piping system 3 that supplies air (oxygen) as an oxidant gas to the fuel cell 2, and a fuel gas that supplies hydrogen gas as a fuel gas to the fuel cell 2. A piping system 4 and a control device 7 that controls the number of revolutions of a motor M3 that drives the compressor 14 based on detection data from an outside air temperature sensor 51, a pressure sensor P1, a temperature sensor 48, and the like are provided.

  The fuel cell 2 is formed of, for example, a solid polymer electrolyte type and has a stack structure in which a large number of single cells are stacked. The single cell has an oxidant electrode (cathode) on one side of an electrolyte made of an ion exchange membrane (for example, a fluororesin ion exchange membrane), a fuel electrode (anode) on the other side, and is further oxidized. A pair of separators are provided so as to sandwich the agent electrode and the fuel electrode from both sides. An oxidant gas is supplied to the oxidant gas flow path 2a of one separator, and a fuel gas is supplied to the fuel gas flow path 2b of the other separator. The fuel cell 2 generates electric power by an electrochemical reaction between the supplied fuel gas and oxidant gas. The electrochemical reaction in the fuel cell 2 is an exothermic reaction, and the temperature of the solid polymer electrolyte fuel cell 2 is approximately 60 to 80 ° C.

  The oxidant gas piping system 3 has a supply flow path 11 through which the oxidant gas supplied to the fuel cell 2 flows, and a discharge flow path 12 through which the oxidant gas off-gas discharged from the fuel cell 2 flows.

  The downstream end of the supply flow channel 11 communicates with the upstream end of the oxidant gas flow channel 2a, and the upstream end of the discharge flow channel 12 communicates with the downstream end of the oxidant gas flow channel 2a. The oxidant off-gas is in a highly wet state because it contains moisture generated by the cell reaction of the fuel cell 2.

  In the supply flow path 11, a compressor 14 that takes in an oxidant gas (outside air) in order from the upstream through an air cleaner 13, and an oxidant gas that has been compressed by the compressor 14 to a high temperature (for example, 130 ° C.) A heat exchanger 8 as a cooling means for cooling by exchanging heat with an oxidant gas off-gas (for example, 70 ° C.) discharged from the battery 2, a temperature sensor 48 for detecting the outlet temperature of the heat exchanger 8, and a compressor And a humidifier 15 for humidifying the oxidant gas pressure-fed by the fuel cell 2 to the fuel cell 2. The humidifier 15 is provided between the downstream portion of the compressor 14 and the discharge flow path 12, and a low wet oxidant gas flowing in the supply flow path 11 and a high wet oxidation flowing in the discharge flow path 12. Water is exchanged with the agent off gas, and the oxidant gas supplied to the fuel cell 2 is appropriately humidified.

  The discharge flow path 12 includes a pressure sensor P1 that detects the oxidant gas pressure in the fuel cell 2 in order from the upstream, a pressure regulating valve 16 that regulates the back pressure of the oxidant gas supplied to the fuel cell 2, and a humidifier 15. A cooler 40 for cooling the oxidant gas off-gas, a heat exchanger 8 for cooling the oxidant gas by exchanging heat between the oxidant gas and the oxidant gas off-gas flowing through the supply flow path 11, and compression A drive motor M1 of the machine 14 and a muffler 9 are provided.

  The pressure regulating valve 16 is configured by, for example, a butterfly valve driven by a step motor, and is electrically connected to the control device 7. The valve opening degree of the pressure regulating valve 16 is configured to be adjustable in an arbitrary range by the control device 7.

  The fuel gas piping system 4 includes a hydrogen supply source 21, a supply path 22 through which hydrogen gas supplied from the hydrogen supply source 21 to the fuel cell 2 flows, a discharge path 23 through which unused hydrogen gas flows, and a discharge path 23. And a purge path 25 connected thereto. The purge passage 25 is provided with a purge valve 33 for discharging the hydrogen off gas to a hydrogen diluter (not shown). The hydrogen gas flowing out from the hydrogen supply source 21 to the supply path 22 by opening the main valve 26 is supplied to the fuel cell 2 through the pressure regulating valve 27 and other pressure reducing valves and the shutoff valve 28.

  The control device 7 is configured as a microcomputer having a CPU, ROM, and RAM therein. The CPU executes a desired calculation according to the control program and performs various processes and controls such as operation control. The ROM stores control programs and control data processed by the CPU. The RAM is mainly used as various work areas for control processing.

  The control device 7 includes a pressure sensor (P1) and a temperature sensor (48) used in the gas system (3, 4), an outside air temperature sensor 51 for detecting an outside air temperature in the environment where the fuel cell system 1 is placed, and a vehicle Input detection signals from various sensors such as an accelerator position sensor (not shown) for detecting the accelerator position, and control each component (compressor 14 and control unit) for controlling the flow of the oxidant gas flowing through the fuel cell system 1. A control signal is output to the pressure valve 16 or the like.

  Next, the operation of the system during normal operation according to the present embodiment will be described with reference to FIG. As shown in FIG. 1, in a vehicle using the fuel cell system 1, when the driver is stepping on an accelerator (not shown) when the driver is stepping on an accelerator (not shown) during normal driving when driving on a flat road, for example, The degree is detected by an accelerator opening sensor (not shown), and the detected value is transmitted to the control device 7.

  The control device 7 derives the necessary power generation amount in the fuel cell 2 based on the transmitted detection data, and the supply amount of the oxidant gas to be supplied to the fuel cell 2 is derived based on the derived power generation amount. .

  The control device 7 controls the rotational speed of the driving motor M1 of the compressor 14 based on the derived necessary oxidant gas amount data, and supplies the necessary amount of oxidant gas via the air cleaner 13 to the oxidant of the fuel cell 2. Supply to the pole. The temperature of the oxidant gas compressed and discharged by the compressor 14 rises to about 130 ° C., for example. The oxidant gas discharged from the compressor 14 is introduced into the heat exchanger 8.

  The oxidant gas introduced into the heat exchanger 8 is heat-exchanged with the oxidant gas off-gas and cooled to, for example, 100 ° C. or lower. Here, the oxidant gas off-gas that has been discharged from the fuel cell 2 and then radiated by the cooler 40 such as a radiator having a cooling fan and further cooled is used as the oxidant gas off-gas to be heat-exchanged. Note that the oxidant gas off-gas may be directly heat-exchanged by the heat exchanger 8 without providing the cooler 40. Further, the cooling of the oxidant gas is not limited to heat exchange with the oxidant gas off-gas, and for example, a water-cooled heat exchanger or a radiator can be used as the cooling means 17 (see FIG. 3). The temperature of the oxidant gas is detected by a temperature sensor 48 provided downstream of the heat exchanger 8, and the detected temperature is transmitted to the control device 7.

  The control device 7 determines that the temperature is appropriate when the temperature detected by the temperature sensor 48 is a predetermined temperature, for example, 100 ° C. or less. Then, the oxidant gas is introduced into the humidifier 15, humidified, and heat-exchanged with the oxidant gas off-gas, further cooled to a temperature of, for example, 80 ° C. or less, and supplied to the oxidant electrode of the fuel cell 2.

  Further, the oxidant gas off-gas which has been heat-exchanged with the oxidant gas in the heat exchanger 8 and has been heated to, for example, 100 ° C. passes through the heat exchanger 8 and is then cooled for the cooling provided in the driving motor M1 of the compressor 14. It is introduced into the interior space (not shown). A plurality of fins are provided in the internal space in order to efficiently dissipate heat. Then, the oxidant gas off-gas is heat-exchanged with the drive motor M1 having a temperature higher than that of the oxidant gas off-gas, for example, about 130 ° C. while being in contact with the fin surface, thereby cooling the drive motor M1. Then, the oxidant gas off-gas that has been heat-exchanged and heated is passed through the muffler 9 and released to the atmosphere. Here, when the oxidant gas is cooled by the cooling means 17 without heat exchange with the oxidant gas off-gas, the oxidant gas off-gas discharged from the fuel cell 2 is directly used for driving the compressor 14 as shown in FIG. It is introduced into the motor M1 to cool the drive motor M1. In this case, the oxidant gas off-gas that cools the driving motor M1 passes through the cooler 40 such as a radiator having a cooling fan after being discharged from the fuel cell 2, and is then introduced into the driving motor M1. Good.

  The oxidant gas at an appropriate temperature supplied to the oxidant electrode of the fuel cell 2 through the supply channel 11 reacts with the hydrogen supplied to the hydrogen electrode via the exchange membrane to generate power.

  Next, an operation according to the present embodiment when the vehicle continues traveling in a high load environment such as when the vehicle climbs a steep slope will be described. When the vehicle is operated in a high load environment, it is necessary to pump more oxidant gas to the fuel cell 2 than during normal operation, and control is performed by increasing the rotational speed of the compressor 14.

  Based on the derived necessary oxidant gas amount data, the control device 7 controls the rotational speed of the drive motor M1 of the compressor 14 at a higher speed than during normal operation, and supplies the necessary amount of oxidant gas via the air cleaner 13. The oxidant electrode of the fuel cell 2 is supplied. The highly compressed oxidant gas discharged from the compressor 14 may rise to a temperature higher than that during normal operation, for example, a temperature exceeding 130 ° C. The high-temperature oxidant gas pumped from the compressor 14 is introduced into the heat exchanger 8.

  The oxidant gas introduced into the heat exchanger 8 is discharged from the fuel cell 2 through the discharge flow path 12, is heat-exchanged with the outside air by the cooler 40, is cooled, and is introduced into the heat exchanger 8. Heat exchange is performed with the oxidant gas off-gas and the heat is sent to the humidifier 15. At this time, the temperature sensor 48 provided downstream of the heat exchanger 8 detects the outlet temperature of the sent oxidant gas and transmits it to the control device 7.

  If the detected temperature exceeds a predetermined temperature, for example, 100 ° C., the control device 7 determines that the temperature is not appropriate for the fuel cell 2 and executes the following control for cooling the oxidant gas.

  The control device 7 reduces the amount of heat transmitted from the motor M1 to the oxidant gas in the compressor 14 by lowering the rotational speed of the drive motor M1 of the compressor 14 and lowering the heat generation amount of the motor M1, thereby increasing the temperature of the oxidant gas. Suppress. The control device 7 performs feedback control while detecting the oxidant gas temperature with the temperature sensor 48, and performs control to gradually reduce the rotational speed of the drive motor M1 until the temperature reaches an appropriate temperature (for example, 100 ° C. or lower). The oxidant gas thus cooled is introduced into the humidifier 15. Then, heat is further exchanged with the oxidant gas off-gas in the humidifier 15, and the temperature is lowered to, for example, 80 ° C. or less and supplied into the fuel cell 2. When the above control is performed, the rotational speed of the compressor 14 is lowered and the supply amount of the oxidant gas is less than the required amount. Just control it.

  Further, when the oxidant gas off-gas is cooled by the cooler 40 (for example, when the cooling fan is operated by the control device 7 through the radiator provided with the cooling fan), the oxidant gas off-gas is further cooled, so that it is efficiently oxidized. The agent gas temperature can be adjusted to an appropriate temperature, and the power supply time from the battery can be shortened. The oxidant gas off-gas which has been heat-exchanged with the oxidant gas and has risen to 100 ° C., for example, is introduced into the internal space for cooling provided in the driving motor M1 of the compressor 14 and heat-exchanged in the same manner as during normal operation. The drive motor M1 is cooled. The heated oxidant gas off-gas passes through the muffler 9 and is released to the atmosphere.

  Next, the control of the oxidant gas temperature will be described based on the flowchart 1 of FIG. As shown in FIG. 2, the control starts in step S <b> 10, and the outlet temperature temp of the heat exchanger 8 is detected by the temperature sensor 48 in step S <b> 11 and transmitted to the control device 7.

  Next, it is confirmed whether or not the detected temperature temp is higher than a predetermined temperature, for example, 100 ° C. If it is 100 ° C. or lower, the determination flag remains 0, and if it is higher than 100 ° C., the flag is set to 1 (step S12).

  Next, in step S13, the flag is confirmed. If the flag is 0, it is determined that the oxidant gas temperature is appropriate, and the process proceeds to step S15 and the program is terminated. If the flag is 1, it is determined that the oxidant gas temperature is too high, and control is performed to reduce the rotation speed rpm of the compressor 14 by a predetermined amount according to the detected temperature temp. That is, if the detected temperature greatly deviates from a reference temperature (for example, 100 ° C.), the rotational speed rpm of the compressor 14 is greatly decreased, and if the detected temperature deviates slightly, the rotational speed rpm of the compressor 14 is decreased. Decrease control.

  And it returns to step S11 after the predetermined time which performed control which reduces rotation speed rpm, and temperature temp which temperature sensor 48 detected is received. Then, steps S11 to S14 of the flowchart 1 are repeated until the temperature temp becomes 100 ° C. or less, for example. When the temperature temp becomes 100 ° C. or less, the process proceeds from step S13 to step S15 and the control is terminated.

  As is clear from the above description, in the first embodiment, the oxidant gas is heat-exchanged by the oxidant gas off-gas and the heat exchanger 8 and cooled to an appropriate temperature. Then, the oxidant gas off-gas heat-exchanged with the oxidant gas is introduced into the motor M1 that drives the compressor 14, and heat exchange is performed to cool the motor M1, so that a water-cooled cooling device may not be provided. This eliminates the need for pipes, radiators, cooling water pumps, control systems, and the like that were necessary to provide a water-cooled cooling system, which can greatly reduce costs and reduce the size of the system. be able to.

  In the first embodiment, a cooler 40 for cooling the oxidant gas off-gas is provided between the humidifier 15 and the heat exchanger 8 in the discharge channel 12. As a result, the oxidant gas off-gas is further cooled down before being introduced into the heat exchanger 8, and the oxidant gas and the motor M1 for driving the compressor 14 can be reliably cooled, thereby improving the reliability.

  In the first embodiment, a temperature sensor 48 is provided downstream of the heat exchanger 8 in the supply flow path 11, and the oxidant gas temperature detected by the temperature sensor 48 is higher than a predetermined temperature (for example, 100 ° C.). In some cases, control is performed to reduce the temperature of the oxidant gas by reducing the rotational speed of the motor M1 that drives the compressor 14. As a result, even if there is no water-cooling type cooling device, it is possible to prevent the high-temperature oxidant gas from being supplied to the fuel cell, thereby improving the reliability.

  Further, in the first embodiment, an oxidant gas off-gas is used for cooling the motor M1 that drives the compressor 14. Therefore, for example, there is no restriction that the motor M1 must be placed at the front of the vehicle in order to cool the motor M1. Thereby, since the mounting place of the compressor 14 is not limited, the freedom degree of mounting design increases. Further, since the heat exchanger 8 is usually placed in the vicinity of the compressor 14, the piping for introducing the oxidant gas off-gas introduced into the heat exchanger 8 into the motor M1 for driving the compressor 14 can be shortened and the cost can be reduced. Can be achieved.

  In the first embodiment, a heat exchanger 8 is provided on the supply flow path 11 as a cooling means for cooling the oxidant gas compressed by the compressor 14 by exchanging heat with the oxidant gas off-gas. The pressure sensor P1, the pressure regulating valve 16, the humidifier 15, the cooler 40, the heat exchanger 8, the motor M1 that drives the compressor 14, and the muffler 9 are sequentially arranged on the discharge flow path 12 from upstream. Was provided. The oxidant gas off-gas flowing through the discharge flow path 12 is cooled by the cooler 40, and after the cooled oxidant gas off-gas is introduced into the heat exchanger 8 and heat-exchanged with the oxidant gas and heated, It was introduced into the motor M1 that drives the compressor 14, and the motor M1 was cooled. However, the present invention is not limited to this configuration, and as shown in FIG. 3 as a second embodiment, cooling means 17 for cooling the oxidant gas is provided on the supply flow path 11 by using, for example, a water-cooled heat exchanger or a radiator. The pressure sensor P1, the pressure regulating valve 16, the motor M1 that drives the compressor 14, and the muffler 9 are provided on the discharge flow path 12 in order from the upstream, and the oxidant gas off-gas that has passed through the pressure regulating valve 16 is directly supplied to the motor M1. You may comprise so that it may be introduce | transduced into.

  Also in this manner, as in the first embodiment, the oxidant gas off-gas is introduced into the motor M1 that drives the compressor 14, and heat exchange is performed to cool the motor M1, so that the water-cooled cooling is performed to cool the motor M1. It is not necessary to provide a device. Therefore, piping, a radiator, a cooling water pump, a control system, etc., which are necessary for providing a water-cooled cooling device, are not necessary, and the cost can be reduced and the system can be downsized. .

  In the second embodiment, the oxidant gas off-gas is used for cooling the motor M1 that drives the compressor 14 as in the first embodiment. For example, the vehicle is used to cool the motor M1 by air. There are no restrictions such as having to be placed at the front of. Thereby, since the mounting place of the compressor 14 is not limited, the freedom degree of mounting design increases.

1 is a configuration diagram of a fuel cell system according to a first embodiment of the present invention. It is a flowchart which shows the control content concerning this embodiment. It is a block diagram of the fuel cell system of 2nd Embodiment which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell system, 2 ... Fuel cell, 3 ... Oxidant gas piping system, 4 ... Fuel gas piping system, 7 ... Control apparatus, 8 ... Heat exchanger (cooling means), 9 ... Muffler, 10 ... Heat exchanger DESCRIPTION OF SYMBOLS 11 ... Supply flow path, 12 ... Discharge flow path, 14 ... Compressor, 15 ... Humidifier, 16 ... Pressure regulating valve, 17 ... Cooling means, 40 ... Cooler, 48 ... Temperature sensor, M1 ... Motor (for compressor) ).

Claims (4)

A fuel cell that generates power by supplying fuel gas to the fuel electrode and supplying oxidant gas to the oxidant electrode;
A supply flow path through which the oxidant gas supplied to the fuel cell flows;
A discharge passage through which an oxidant gas off-gas discharged from the fuel cell flows;
A compressor provided in the supply flow path, for pumping the oxidant gas to the fuel cell;
A motor for driving the compressor;
Cooling means for cooling the oxidant gas compressed by the compressor;
A control device for controlling the flow of the oxidant gas supplied to the fuel cell by the compressor;
The fuel cell system, wherein the oxidant gas off-gas is introduced into the motor that drives the compressor to cool the motor. The fuel cell system according to claim 1, further comprising a temperature sensor that detects a temperature of the oxidant gas cooled by the cooling unit in the supply channel.
When the oxidant gas temperature detected by the temperature sensor exceeds a predetermined temperature, the control device controls the rotation of the motor that drives the compressor according to the detected temperature, and the inside of the compressor And adjusting the temperature of the oxidant gas.   3. The fuel cell system according to claim 1, wherein the cooling unit is a heat exchanger that exchanges heat with the oxidant gas off-gas, and the oxidant gas off-gas heat-exchanged by the heat exchanger is A fuel cell system that is introduced into the motor that drives the compressor to cool the motor.   4. The fuel cell system according to claim 3, further comprising a cooler for cooling the oxidant gas off-gas that is heat-exchanged by the heat exchanger in the discharge flow path. 5.

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