fuel cell system

Abstract

To provide a fuel cell system whose structure can be simplified.SOLUTION: A fuel cell system includes a fuel cell, an oxidizing gas supply line for sending oxidizing gas to the fuel cell, a compressor which is provided in the oxidizing gas supply line and configured to compress the oxidizing gas, a cold medium supply line for supplying a cold medium for cooling the fuel cell to the fuel cell, a cold medium pump which is provided in the cold medium supply line and configured to boost the pressure of the cold medium, and an oxidizing gas cooler configured to perform heat exchange between the cold medium flowing through the cold medium supply line and the oxidizing gas which flows downstream of the compressor in the oxidizing gas supply line and is compressed by the compressor.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a fuel cell system configured to supply an oxidizing gas compressed by a compressor to a fuel cell. [Background technology]

[0002] A fuel cell electric vehicle (FCEV) is configured to run by rotating a traction motor using electrical energy generated by a chemical reaction between fuel gas (hydrogen) and oxidizing gas (oxygen) in a fuel cell. The hydrogen supplied to the fuel cell is stored in a hydrogen tank installed in the fuel cell vehicle. The oxygen supplied to the fuel cell comes from the air. An electric compressor is sometimes installed in the oxygen supply system that supplies oxygen to the fuel cell, so that a large amount of air can be sent to the fuel cell and the pressure inside the fuel cell can be maintained.

[0003] Because the air compressed by the electric compressor reaches a high temperature, it must be cooled to a temperature suitable for the fuel cell before being supplied to the fuel cell. Patent Document 1 discloses that the air compressed by the electric compressor is cooled by an air-cooled heat exchanger and a water-cooled heat exchanger before being supplied to the fuel cell. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-120336 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-56865 Summary of the Invention [Problem to be solved by the invention]

[0005] The water-cooled heat exchangers described in Patent Documents 1 and 2 require dedicated lines and pumps to supply water for cooling to the heat exchanger, which may complicate the structure of the fuel cell system equipped with the fuel cell, electric compressor, etc.

[0006] In view of the above circumstances, an object of at least one embodiment of the present disclosure is to provide a fuel cell system that can be simplified in structure. [Means for solving the problem]

[0007] A fuel cell system according to an embodiment of the present disclosure includes: A fuel cell; an oxidizing gas supply line for supplying oxidizing gas to the fuel cell; a compressor provided in the oxidizing gas supply line and configured to compress the oxidizing gas; a cooling medium supply line for supplying a cooling medium for cooling the fuel cell to the fuel cell; a cooling medium pump provided in the cooling medium supply line and configured to increase the pressure of the cooling medium; an oxidizing gas cooler configured to perform heat exchange between the cold medium flowing through the cold medium supply line and the oxidizing gas compressed by the compressor flowing downstream of the compressor in the oxidizing gas supply line. [Effects of the Invention]

[0008] According to at least one embodiment of the present disclosure, a fuel cell system that can be simplified in structure is provided. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of a fuel cell system according to an embodiment; [Figure 2] 1 is a schematic diagram of a fuel cell system according to an embodiment; [Figure 3] 1 is a schematic diagram of a fuel cell system according to an embodiment; [Figure 4]1 is a schematic diagram of a fuel cell system according to an embodiment; [Figure 5] 1 is a schematic diagram of a fuel cell system according to an embodiment; [Figure 6] 1 is a schematic diagram of a fuel cell system according to an embodiment; [Figure 7] 1 is a schematic diagram of a fuel cell system according to an embodiment; [Figure 8] 1 is a schematic diagram of a fuel cell system according to an embodiment; [Figure 9] 1 is a schematic diagram of a fuel cell system according to an embodiment; [Figure 10] 1 is a schematic diagram of a fuel cell system according to an embodiment; [Figure 11] 1 is a schematic diagram of a fuel cell system according to an embodiment; [Figure 12] 1 is a schematic diagram of a fuel cell system according to an embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present disclosure.

[0011] (Fuel cell system) Each of FIGS. 1 to 12 is a schematic diagram of a fuel cell system 1 according to an embodiment of the present disclosure. The temperatures shown in FIGS. 1 to 12 indicate examples of the temperatures of fluids flowing through the respective flow paths. As shown in FIGS. 1 to 12, a fuel cell system 1 according to some embodiments includes a fuel cell (FC) 2 including at least an air electrode 21 and an anode 22, an oxidizing gas supply line 3 for supplying oxidizing gas to the air electrode 21 of the fuel cell 2, and a fuel gas supply line 4 for supplying fuel gas to the anode 22 of the fuel cell 2. The fuel cell system 1 supplies the oxidizing gas and fuel gas to the fuel cell 2, causing the fuel cell 2 to generate electric power. The fuel cell system 1 may be mounted on an electric vehicle (not shown) configured to run on the electric power generated by the fuel cell 2.

[0012] (fuel cell) The fuel cell 2 is supplied (replenished) with an oxidizing gas (oxygen in the air in the illustrated example) that serves as a positive electrode active material and a fuel gas (hydrogen gas in the illustrated example) that serves as a negative electrode active material at room temperature or in a high temperature environment. The fuel cell 2 is configured to generate electricity through an electrochemical reaction between the supplied oxidizing gas and fuel gas.

[0013] In the illustrated embodiment, the oxidizing gas supplied to the fuel cell 2 consists of oxygen in the air, and the fuel gas supplied to the fuel cell 2 consists of hydrogen gas. As shown in FIGS. 1 to 12, the fuel cell 2 has at least one power-generating cell 20 including an air electrode 21 which is an electron-accepting electrode (cathode), a fuel electrode 22 which is an electron-emitting electrode (anode), and an electrolyte membrane 23 sandwiched between the air electrode 21 and the fuel electrode 22 so as to separate the air electrode 21 and the fuel electrode 22. The fuel cell 2 may also have a stacked configuration of a plurality of power-generating cells 20 with separators sandwiched between each of the plurality of power-generating cells 20. In the illustrated embodiment, the electrolyte membrane 23 consists of a solid polymer electrolyte membrane.

[0014] In the fuel cell 2, oxygen-containing air is supplied to the catalyst layer on the air electrode 21 side of each of the plurality of power generation cells 20 via an oxidizing gas supply line 3. In addition, in the fuel cell 2, hydrogen gas is supplied to the catalyst layer on the fuel electrode 22 side of each of the plurality of power generation cells 20 via a fuel gas supply line 4. In the fuel cell 2, when oxygen-containing air is supplied to the air electrode 21 and hydrogen gas is supplied to the fuel electrode 22, a chemical reaction occurs as described below, making it possible to extract electrical energy as electromotive force generated between the electrodes (between the air electrode 21 and the fuel electrode 22). Fuel electrode 22 (anode): H2 → 2H++2e- Air electrode 21 (cathode): 1 / 2O2 + 2H++2e- → H2O

[0015] (Oxidizing gas supply line) 1 to 12, the fuel cell system 1 further includes a compressor 31 that is provided in the oxidizing gas supply line 3 and configured to compress the oxidizing gas. The oxidizing gas supply line 3 includes an oxidizing gas introduction flow path (pipe) 30 that introduces oxygen-containing air (oxidizing gas) compressed by the compressor 31 to the air electrode 21 of the fuel cell 2. One end (upstream end) of the oxidizing gas introduction flow path 30 is connected to the compressor 31, and the other end (downstream end) is connected to the air electrode 21 of the fuel cell 2.

[0016] Due to the suction force generated by rotating the compressor 31, air containing oxygen is guided to the compressor 31 from the upstream side of the compressor 31 on the oxidizing gas supply line 3, and compressed by the compressor 31. The oxygen-containing air compressed by the compressor 31 is supplied to the air electrode 21 (catalyst layer on the air electrode 21 side) of the fuel cell 2 via the oxidizing gas introduction flow path 30.

[0017] In the illustrated embodiment, the compressor 31 includes an electric compressor 31A configured to be driven by an electric motor (electric motor) 32 to compress oxygen gas. The fuel cell system 1 further includes the electric motor 32 that generates a rotational force to rotate the compressor 31, and a rotating shaft 33 that is mechanically coupled to the compressor 31 and the electric motor 32 and transmits the rotational force generated by the electric motor 32 to the compressor 31.

[0018] (Fuel gas supply line) As shown in FIGS. 1 to 12, the fuel cell system 1 further includes a fuel gas storage device (e.g., a hydrogen gas storage tank) 41 configured to store fuel gas (hydrogen gas). The fuel gas supply line 4 includes a flow path (pipe) for supplying fuel gas from the fuel gas storage device 41 to the fuel electrode 22 (catalytic layer on the fuel electrode 22 side) of the fuel cell 2. One end (upstream end) of the fuel gas supply line 4 is connected to the fuel gas storage device 41, and the other end (downstream end) is connected to the fuel electrode 22 of the fuel cell 2. The fuel gas stored in the fuel gas storage device 41 is supplied to the fuel electrode 22 (catalytic layer on the fuel electrode 22 side) of the fuel cell 2 via the fuel gas supply line 4.

[0019] 1 to 7, 11 and 12, the fuel cell system 1 may further include a first fuel gas flow rate control valve 42 that is provided in the fuel gas supply line 4 and is configured to be able to adjust the flow rate of the fuel gas passing through the fuel gas supply line 4. By adjusting the aperture of the first fuel gas flow rate control valve 42, the flow rate of the fuel gas flowing on the fuel gas supply line 4 downstream of the first fuel gas flow rate control valve 42 is adjusted.

[0020] When the first fuel gas flow rate control valve 42 is fully closed, the pressure on the upstream side of the first fuel gas flow rate control valve 42 in the fuel gas supply line 4 (the side where the fuel gas storage device 41 is located) is higher than the pressure on the downstream side of the first fuel gas flow rate control valve 42 in the fuel gas supply line 4 (the side where the fuel electrode 22 of the fuel cell 2 is located). Due to the pressure difference between the upstream side and downstream side of the first fuel gas flow rate control valve 42 in the fuel gas supply line 4, when the first fuel gas flow rate control valve 42 is opened, fuel gas flows from the upstream side to the downstream side of the fuel gas supply line 4.

[0021] (Fuel gas discharge line) As shown in FIGS. 1 to 12, the fuel cell system 1 may include a fuel gas discharge line 7 for sending excess fuel gas discharged from the fuel electrode 22 of the fuel cell 2. One end (upstream end) of the fuel gas discharge line 7 is connected to the fuel electrode 22 of the fuel cell 2. The fuel gas extracted from the fuel cell 2 to the fuel gas discharge line 7 is discharged to the outside of the fuel cell system 1 via the fuel gas discharge line 7.

[0022] 1 to 12, the fuel cell system 1 may further include a second fuel gas flow rate adjustment valve 71 that is provided in the fuel gas discharge line 7 and is configured to be able to adjust the flow rate of the fuel gas passing through the fuel gas discharge line 7. By adjusting the aperture of the second fuel gas flow rate adjustment valve 71, the flow rate of the fuel gas flowing on the fuel gas discharge line 7 downstream of the second fuel gas flow rate adjustment valve 71 is adjusted.

[0023] When the second fuel gas flow rate control valve 71 is fully closed, the pressure on the upstream side of the second fuel gas flow rate control valve 71 in the fuel gas discharge line 7 (the side where the fuel electrode 22 is located) is higher than the pressure on the downstream side of the second fuel gas flow rate control valve 71 in the fuel gas discharge line 7. Due to the pressure difference between the upstream side and downstream side of the second fuel gas flow rate control valve 71 in the fuel gas discharge line 7, when the second fuel gas flow rate control valve 71 is opened, fuel gas flows from the upstream side to the downstream side of the fuel gas discharge line 7.

[0024] Each of the first fuel gas flow control valve 42 and the second fuel gas flow control valve 71 may be an on-off valve whose opening can be adjusted to fully closed or fully open, or may be an opening adjustment valve whose opening can be adjusted to fully closed, fully open, or at least one intermediate opening between these.

[0025] (exhaust gas line) As shown in FIGS. 1 to 12, the fuel cell system 1 further includes an exhaust gas line 5 for transmitting exhaust gas discharged from the air electrode 21 of the fuel cell 2. The exhaust gas discharged from the air electrode 21 of the fuel cell 2 contains exhaust (water vapor) generated by an electrochemical reaction between a fuel gas (hydrogen) and an oxidizing gas (oxygen) in the fuel cell 2. One end (upstream end) of the exhaust gas line 5 is connected to the air electrode 21 of the fuel cell 2. The exhaust gas extracted from the fuel cell 2 to the exhaust gas line 5 is discharged to the outside of the fuel cell system 1 via the exhaust gas line 5.

[0026] As shown in FIGS. 1 to 12, the fuel cell system 1 further includes a turbine (expander) 51 that is provided in the exhaust gas line 5 and configured to be driven by exhaust gas. The exhaust gas discharged from the air electrode 21 of the fuel cell 2 is guided to the turbine 51 via the exhaust gas line 5. The turbine 51 is configured to rotate by the energy (expansion energy) of the exhaust gas guided to the turbine 51. The turbine 51 is configured to expand the exhaust gas guided to the turbine 51.

[0027] In the illustrated embodiment, the turbine 51 is mechanically coupled to the compressor 31 via the rotating shaft 33. The compressor 31 and the turbine 51 are coaxially arranged with each other via the rotating shaft 33, which is the output shaft of the electric motor 32 for driving the compressor 31, and are each connected to the rotating shaft 33. The electric motor 32 is supplied with current from a power source (such as a generator) (not shown), and is driven by the current supplied from the power source to drive (rotate) the rotating shaft 33, the compressor 31, and the turbine 51. The turbine 51 recovers a portion of the expansion energy generated when the exhaust gas expands, and the recovered expansion energy assists in driving (rotating) the compressor 31. The electric motor 32 may be driven by power generated by the fuel cell 2.

[0028] (Cooling medium supply line) 1 to 12, the fuel cell system 1 further includes a cold medium supply line 6 for supplying a cold medium for cooling the fuel cell 2 to the fuel cell 2, and a cold medium pump 61 provided in the cold medium supply line 6 and configured to increase the pressure of the cold medium. The cold medium supply line 6 includes at least a cold medium supply flow path (pipe) having one end (upstream end) connected to the cold medium pump 61 and the other end (downstream end) connected to the fuel cell 2.

[0029] The fuel cell 2 is configured to perform heat exchange between the gas inside the fuel cell 2 (oxidizing gas or fuel gas) and a cooling medium (a coolant such as water) that is introduced into the fuel cell 2 and has a lower temperature than the gas inside the fuel cell 2. Through heat exchange in the fuel cell 2, the gas inside the fuel cell 2 is cooled by the cooling medium introduced into the fuel cell 2. The cooling medium may flow through a flow path formed inside the separator, and may perform heat exchange with the gas inside the fuel cell 2 in this flow path. Note that the fuel cell 2 is configured so that the gas inside the fuel cell 2 and the cooling medium do not mix.

[0030] In the illustrated embodiment, the cold medium supply line 6 is a cold medium circulation line 60A for circulating the cold medium, and includes a cold medium circulation line 60A provided with a cold medium pump 61 and a fuel cell 2. The cold medium is pressurized by the cold medium pump 61, causing it to circulate through the cold medium circulation line 60A (cold medium supply line 6).

[0031] The cold medium pump 61 may be connected to a drive shaft of the electric motor 62 and may be configured to be driven by the electric motor 62. The electric motor 62 is supplied with current from a power source (such as a generator) (not shown), and is driven by the current supplied from the power source to drive the cold medium pump 61 (to rotate the rotor blades of the cold medium pump 61). The electric motor 62 may also be driven by being supplied with electric power generated by the fuel cell 2.

[0032] (Oxidizing gas cooler) As shown in Figures 1 to 12, the fuel cell system 1 according to some embodiments further includes an oxidizing gas cooler 63 configured to perform heat exchange between the cold medium flowing through the above-mentioned cold medium supply line 6 and the oxidizing gas compressed by the compressor 31 flowing downstream of the compressor 31 in the above-mentioned oxidizing gas supply line 3.

[0033] The cold medium pressurized by the cold medium pump 61 is introduced into the oxidizing gas cooler 63 via the cold medium supply line 6. The cold medium introduced into the oxidizing gas cooler 63 has a lower temperature (for example, about 50°C) than the oxidizing gas introduced into the oxidizing gas cooler 63. Therefore, the oxidizing gas is cooled and the cold medium is heated by heat exchange in the oxidizing gas cooler 63. The oxidizing gas cooled in the oxidizing gas cooler 63 is introduced to the air electrode 21 of the fuel cell 2.

[0034] According to the above configuration, the oxidizing gas supplied to the fuel cell 2 can be cooled by heat exchange in the oxidizing gas cooler 63. As a result, the oxidizing gas compressed in the compressor 31 and heated to a relatively high temperature (for example, about 200°C) can be cooled to a temperature suitable for the chemical reaction in the fuel cell 2 (for example, about 60°C) before being supplied to the fuel cell 2. In the fuel cell system 1, the cooling system of the fuel cell 2, such as the cooling medium supply line 6 and the cooling medium pump 61, is used to supply the cooling medium to the oxidizing gas cooler 63, so dedicated lines and pumps are not required, and the structure of the fuel cell system 1 can be simplified.

[0035] 1 to 12, in some embodiments, the above-described cold medium supply line 6 includes the above-described cold medium circulation line 60A and a bypass line 60B that bypasses the fuel cell 2. The bypass line 60B branches off from the cold medium circulation line 60A at a branch point P1 upstream of the fuel cell 2 on the cold medium circulation line 60A and downstream of the cold medium pump 61. The bypass line 60B merges with the cold medium circulation line 60A at a junction P2 downstream of the fuel cell 2 on the cold medium circulation line 60A and upstream of the cold medium pump 61. The oxidant gas cooler 63 is provided on the bypass line 60B. In this case, the fuel cell 2 and the oxidant gas cooler 63 are each supplied with a cold medium that has not cooled the other of the fuel cell 2 and the oxidant gas cooler 63, so that the fuel cell 2 and the oxidant gas cooler 63 can be effectively cooled by the cold medium. In some other embodiments, the oxidant gas cooler 63 may be disposed upstream or downstream of the fuel cell 2 in the cooling medium circulation line 60A (cooling medium supply line 6).

[0036] 1, 2, and 4 to 10, the fuel cell system 1 may further include a radiator (cooler) 64 for cooling the cold medium flowing through the cold medium supply line 6. In the illustrated embodiment, the radiator 64 is provided in the bypass line 60B, but it may also be provided in the cold medium circulation line 60A. The cold medium whose temperature has increased in the fuel cell 2 or the oxidizing gas cooler 63 is cooled in the radiator 64. This maintains the temperature of the cold medium flowing through the cold medium supply line 6.

[0037] (1st heat exchanger) In some embodiments, as shown in FIG. 1, the above-described fuel cell system 1 further includes a first heat exchanger 52 configured to perform heat exchange between the exhaust gas flowing downstream of the turbine 51 in the exhaust gas line 5 and the oxidizing gas flowing downstream of the compressor 31 in the oxidizing gas supply line 3.

[0038] The exhaust gas line 5 includes a first exhaust gas introduction flow path (pipe) 50A for guiding the exhaust gas expanded by the turbine 51 to the first heat exchanger 52. One end (upstream end) of the first exhaust gas introduction flow path 50A is connected to the turbine 51, and the other end (downstream end) is connected to the first heat exchanger 52.

[0039] The exhaust gas, which has been expanded by the turbine 51 and whose temperature has been reduced, is introduced into the first heat exchanger 52 via the first exhaust gas introduction passage 50A. The exhaust gas introduced into the first heat exchanger 52 has a lower temperature (for example, about 10°C) than the oxidizing gas introduced into the first heat exchanger 52. Therefore, the oxidizing gas is cooled and the exhaust gas is heated by heat exchange in the first heat exchanger 52. The oxidizing gas cooled in the first heat exchanger 52 and the oxidizing gas cooler 63 is introduced to the air electrode 21 of the fuel cell 2.

[0040] 1, the first heat exchanger 52 is provided upstream of the oxidizing gas cooler 63 on the oxidizing gas supply line 3. The oxidizing gas cooled in the first heat exchanger 52 is guided to the oxidizing gas cooler 63.

[0041] According to the above configuration, the oxidizing gas supplied to the fuel cell 2 can be cooled by heat exchange in the first heat exchanger 52. By using exhaust gas that has expanded in the turbine 51 and reached a relatively low temperature (for example, approximately 10°C) to cool the oxidizing gas supplied to the fuel cell 2, it is possible to suppress the loss of cold heat in the cooling system of the fuel cell 2 and simplify the structure of the fuel cell system 1. Note that although the fuel cell system 1 includes the first heat exchanger 52, it may be configured without including at least one of the other heat exchangers or coolers, such as the oxidizing gas cooler 63.

[0042] (Fuel cell cooler) In some embodiments, as shown in FIG. 2, the above-described fuel cell system 1 further includes a fuel cell cooler 53 configured to cool the fuel cell 2 using exhaust gas flowing downstream of the turbine 51 in the above-described exhaust gas line 5.

[0043] The exhaust gas line 5 includes a third exhaust gas introduction flow path (pipe) 50C for guiding the exhaust gas expanded by the turbine 51 to the fuel cell cooler 53. One end (upstream end) of the third exhaust gas introduction flow path 50C is connected to the turbine 51, and the other end (downstream end) is connected to the fuel cell cooler 53. The first exhaust gas introduction flow path 50A and the third exhaust gas introduction flow path 50C may share a flow path (pipe) from the end connected to the turbine 51 to the branch point P4.

[0044] The exhaust gas expanded by the turbine 51 and cooled is introduced to the fuel cell cooler 53 via the third exhaust gas introduction passage 50C. The fuel cell cooler 53 is configured to perform heat exchange between the gas inside the fuel cell 2 (oxidizing gas and fuel gas) and the exhaust gas introduced to the fuel cell cooler 53, which has a lower temperature than the gas inside the fuel cell 2. The heat exchange in the fuel cell cooler 53 cools the gas inside the fuel cell 2 with the exhaust gas introduced to the fuel cell cooler 53. The exhaust gas flows through a passage formed inside the separator, and may exchange heat with the gas inside the fuel cell 2 in this passage. The fuel cell cooler 53 is configured to prevent the gas inside the fuel cell 2 and the exhaust gas inside the fuel cell cooler 53 from mixing.

[0045] According to the above configuration, the fuel cell 2 can be cooled in the fuel cell cooler 53. By using exhaust gas that has expanded in the turbine 51 and reached a relatively low temperature (for example, about 10°C) to cool the fuel cell 2, it is possible to suppress the loss of cold heat in the cooling system of the fuel cell 2 and simplify the structure of the fuel cell system 1. Note that although the fuel cell system 1 includes the fuel cell cooler 53, it may be configured without including at least one of the other heat exchangers or coolers, such as the oxidant gas cooler 63.

[0046] (Second heat exchanger) In some embodiments, as shown in FIG. 3, the fuel cell system 1 further includes a second heat exchanger 54 configured to exchange heat between the exhaust gas flowing downstream of the turbine 51 in the exhaust gas line 5 and the cold medium flowing in the cold medium supply line 6.

[0047] The exhaust gas line 5 includes a fourth exhaust gas introduction passage (pipe) 50D for guiding the exhaust gas expanded by the turbine 51 to the second heat exchanger 54. One end (upstream end) of the fourth exhaust gas introduction passage 50D is connected to the turbine 51, and the other end (downstream end) is connected to the second heat exchanger 54.

[0048] The second heat exchanger 54 is provided on the bypass line 60B (cold medium supply line 6). Exhaust gas that has been expanded by the turbine 51 and whose temperature has been reduced is introduced to the second heat exchanger 54 via the fourth exhaust gas introduction passage 50D. The exhaust gas introduced to the second heat exchanger 54 has a lower temperature (for example, about 10°C) than the cold medium introduced to the second heat exchanger 54. Therefore, the cold medium is cooled and the exhaust gas is heated by heat exchange in the second heat exchanger 54.

[0049] According to the above configuration, the cold medium flowing through the cold medium supply line 6 can be cooled by heat exchange in the second heat exchanger 54. By using exhaust gas that has expanded in the turbine 51 and reached a relatively low temperature (approximately 10°C) to cool the cold medium, it is possible to suppress cold heat loss in the cooling system of the fuel cell 2 and simplify the structure of the fuel cell system 1. Note that although the fuel cell system 1 includes the second heat exchanger 54, it may be configured without including at least one of the other heat exchangers or coolers, such as the oxidant gas cooler 63.

[0050] (Third heat exchanger) In some embodiments, as shown in FIG. 4, the above-mentioned fuel cell system 1 further includes a third heat exchanger 55 configured to perform heat exchange between the exhaust gas flowing upstream of the turbine 51 in the above-mentioned exhaust gas line 5 and the oxidizing gas flowing downstream of the compressor 31 in the oxidizing gas supply line 3.

[0051] The exhaust gas line 5 includes a fifth exhaust gas introduction flow path (pipe) 50E for guiding the exhaust gas discharged from the air electrode 21 of the fuel cell 2 to the turbine 51. One end (upstream end) of the fifth exhaust gas introduction flow path 50E is connected to the air electrode 21 of the fuel cell 2, and the other end (downstream end) is connected to the turbine 51.

[0052] The exhaust gas before being introduced into the turbine 51 is introduced into the third heat exchanger 55 via a fifth exhaust gas introduction flow path (pipe) 50E. The exhaust gas introduced into the third heat exchanger 55 has a lower temperature (for example, about 80°C) than the oxidizing gas introduced into the third heat exchanger 55. Therefore, the oxidizing gas is cooled and the exhaust gas is heated by heat exchange in the third heat exchanger 55. The oxidizing gas cooled in the third heat exchanger 55 and the oxidizing gas cooler 63 is introduced to the air electrode 21 of the fuel cell 2.

[0053] 4, the third heat exchanger 55 is provided upstream of the oxidizing gas cooler 63 on the oxidizing gas supply line 3. The oxidizing gas cooled in the third heat exchanger 55 is guided to the oxidizing gas cooler 63.

[0054] According to the above configuration, the oxidizing gas supplied to the fuel cell 2 can be cooled by heat exchange in the third heat exchanger 55. By using the exhaust gas at a relatively low temperature (about 80°C) before being introduced into the turbine 51 to cool the oxidizing gas supplied to the fuel cell 2, it is possible to suppress the loss of cold energy in the cooling system of the fuel cell 2 and simplify the structure of the fuel cell system 1.

[0055] According to the above configuration, the exhaust gas can be heated by heat exchange in the third heat exchanger 55 before being introduced into the turbine 51. By raising the temperature of the exhaust gas introduced into the turbine 51, the amount of energy that can be recovered in the turbine 51 can be increased. When the turbine 51 is connected to the compressor 31 via the rotating shaft 33, the amount of assistance that the turbine 51 provides in driving (rotating) the compressor 31 can be increased by increasing the energy that can be recovered in the turbine 51. This makes it possible to reduce the power required to drive (rotate) the compressor 31 (for example, the power consumption of the electric motor 32). Note that while the fuel cell system 1 includes the third heat exchanger 55, it may be configured without including at least one of the other heat exchangers or coolers, such as the oxidant gas cooler 63.

[0056] (Motor cooler) 1 to 4, in some embodiments, the compressor 31 includes an electric compressor 31A configured to be driven by an electric motor 32 to compress the oxidizing gas. The fuel cell system 1 further includes a motor cooler 56 configured to cool the electric motor 32 by exhaust gas flowing downstream of the turbine 51 in the exhaust gas line 5.

[0057] The exhaust gas line 5 includes a second exhaust gas introduction passage (pipe) 50B for guiding the exhaust gas expanded by the turbine 51 to the motor cooler 56. One end (upstream end) of the second exhaust gas introduction passage 50B is connected to the turbine 51, and the other end (downstream end) is connected to the motor cooler 56. As shown in FIGS. 1 and 2, the first exhaust gas introduction passage 50A and the second exhaust gas introduction passage 50B may share a common passage (pipe) extending from the end connected to the turbine 51 to the branch point P3. As shown in FIG. 3, the second exhaust gas introduction passage 50B and the fourth exhaust gas introduction passage 50D may share a common passage (pipe) extending from the end connected to the turbine 51 to the branch point P5.

[0058] The exhaust gas that has been expanded by the turbine 51 and has a lowered temperature is introduced to the motor cooler 56 via the second exhaust gas introduction passage 50B. The motor cooler 56 is configured to perform heat exchange between the electric motor 32 and the exhaust gas that has been introduced to the motor cooler 56 and has a lower temperature than the electric motor 32. Through the heat exchange in the motor cooler 56, the electric motor 32 is cooled by the exhaust gas introduced to the motor cooler 56.

[0059] According to the above configuration, the electric motor 32 can be cooled in the motor cooler 56. By using exhaust gas that has expanded in the turbine 51 and reached a relatively low temperature (approximately 10°C) to cool the electric motor 32, overheating of the electric motor 32 can be prevented and the structure of the fuel cell system 1 can be simplified. Note that although the fuel cell system 1 includes the motor cooler 56, it may be configured without at least one of the other heat exchangers or coolers, such as the oxidant gas cooler 63.

[0060] (4th heat exchanger) In some embodiments, the above-mentioned fuel cell system 1 further includes a fourth heat exchanger 43 configured to perform heat exchange between the fuel gas flowing through the above-mentioned fuel gas supply line 4 and the oxidizing gas flowing upstream of the compressor 31 of the oxidizing gas supply line 3, as shown in Figures 5, 6, 8, 9 and 11.

[0061] The fuel gas introduced into the fourth heat exchanger 43 has a lower temperature than the oxidizing gas introduced into the fourth heat exchanger 43. Therefore, the heat exchange in the fourth heat exchanger 43 cools the oxidizing gas and heats the fuel gas.

[0062] According to the above configuration, the oxidizing gas before being introduced into the compressor 31 is cooled by heat exchange in the fourth heat exchanger 43, thereby lowering the temperature of the oxidizing gas supplied to the fuel cell 2. As a result, the oxidizing gas compressed in the compressor 31 and heated to a relatively high temperature can be cooled to a temperature (approximately 60°C) suitable for the chemical reaction in the fuel cell 2 before being supplied to the fuel cell 2. Because the fourth heat exchanger 43 uses the cold energy of the fuel gas before being supplied to the fuel cell 2, dedicated lines and pumps are not required, and the structure of the fuel cell system 1 can be simplified.

[0063] According to the above configuration, the oxidant gas is cooled by heat exchange in the fourth heat exchanger 43 before being introduced into the compressor 31, thereby reducing the power (for example, the power consumption of the electric motor 32) required to drive (rotate) the compressor 31. Note that although the fuel cell system 1 includes the fourth heat exchanger 43, it may be configured without including at least one of the other heat exchangers or coolers, such as the oxidant gas cooler 63.

[0064] (5th heat exchanger) In some embodiments, the above-mentioned fuel cell system 1 further includes the above-mentioned fourth heat exchanger 43 and a fifth heat exchanger 44 configured to perform heat exchange between the fuel gas flowing through the fuel gas supply line 4 and the oxidizing gas flowing downstream of the compressor 31 of the oxidizing gas supply line 3, as shown in Figures 6 and 9.

[0065] The fuel gas guided to the fifth heat exchanger 44 has a lower temperature than the oxidizing gas guided to the fifth heat exchanger 44. Therefore, the oxidizing gas is cooled and the fuel gas is heated by heat exchange in the fifth heat exchanger 44. In the illustrated embodiment, the fifth heat exchanger 44 is provided downstream of the fourth heat exchanger 43 on the fuel gas supply line 4. The fifth heat exchanger 44 is also provided downstream of the compressor 31 on the oxidizing gas supply line 3 and upstream of the oxidizing gas cooler 63.

[0066] According to the above configuration, the oxidizing gas supplied to the fuel cell 2 can be cooled by heat exchange in the fifth heat exchanger 44. By using the cold energy of the fuel gas before it is supplied to the fuel cell 2 to cool the oxidizing gas supplied to the fuel cell 2, it is possible to suppress cold energy loss in the cooling system of the fuel cell 2 and simplify the structure of the fuel cell system 1.

[0067] In some embodiments, the fuel cell system 1 described above further includes the fifth heat exchanger 44 described above, as shown in Figures 7 and 10. As shown in Figures 7 and 10, the fuel cell system 1 does not necessarily include the fourth heat exchanger 43 described above.

[0068] According to the above configuration, the oxidizing gas supplied to the fuel cell 2 can be cooled by heat exchange in the fifth heat exchanger 44. By using the cold energy of the fuel gas before it is supplied to the fuel cell 2 to cool the oxidizing gas supplied to the fuel cell 2, it is possible to suppress cold loss in the cooling system of the fuel cell 2 and simplify the structure of the fuel cell system 1. Note that although the fuel cell system 1 includes the fifth heat exchanger 44, it may be configured without including at least one of the other heat exchangers or coolers, such as the oxidizing gas cooler 63.

[0069] (6th heat exchanger) In some embodiments, the above-described fuel cell system 1 further includes the above-described fourth heat exchanger 43 and a sixth heat exchanger 45 configured to exchange heat between the fuel gas flowing through the fuel gas supply line 4 and the cold medium flowing through the cold medium supply line 6, as shown in FIG. 11.

[0070] The fuel gas introduced to the sixth heat exchanger 45 has a lower temperature than the cold medium introduced to the sixth heat exchanger 45. Therefore, the cold medium is cooled and the fuel gas is heated by heat exchange in the sixth heat exchanger 45. In the illustrated embodiment, the sixth heat exchanger 45 is provided downstream of the fourth heat exchanger 43 on the fuel gas supply line 4. The sixth heat exchanger 45 is also provided on the bypass line 60B (cold medium supply line 6).

[0071] According to the above configuration, the cold medium flowing through the cold medium supply line 6 can be cooled by heat exchange in the sixth heat exchanger 45. By using the cold energy of the fuel gas before it is supplied to the fuel cell 2 to cool the cold medium, it is possible to suppress cold loss in the cooling system of the fuel cell 2 and simplify the structure of the fuel cell system 1.

[0072] In some embodiments, the fuel cell system 1 described above further includes the sixth heat exchanger 45 described above, as shown in Figure 12. As shown in Figure 12, the fuel cell system 1 does not necessarily include the fourth heat exchanger 43 described above.

[0073] According to the above configuration, the cold medium flowing through the cold medium supply line 6 can be cooled by heat exchange in the sixth heat exchanger 45. By using the cold energy of the fuel gas before it is supplied to the fuel cell 2 to cool the cold medium, it is possible to suppress cold heat loss in the cooling system of the fuel cell 2 and simplify the structure of the fuel cell system 1. Note that although the fuel cell system 1 includes the sixth heat exchanger 45, it may be configured without including at least one of the other heat exchangers or coolers, such as the oxidant gas cooler 63.

[0074] (Fuel gas storage device) In some embodiments, the above-described fuel gas storage device 41 is configured to store the fuel gas in a liquid state, as shown in Figures 5 to 7, 11, and 12. Here, storing the fuel gas in a liquid state means that most of the fuel gas stored in the fuel gas storage device 41 is in a liquid state.

[0075] According to the above configuration, the fuel gas to be supplied to the fuel cell 2 can be heated by heat exchange in the heat exchanger 43, 44, or 45 in the fuel gas supply line 4, using the fuel gas as a heat medium. This allows the fuel gas to be vaporized before being supplied to the fuel cell 2 and heated to a temperature close to that suitable for the chemical reaction in the fuel cell 2.

[0076] In some embodiments, the above-described fuel gas storage device 41 is configured to store the fuel gas in a gaseous state, as shown in Figures 1 to 4 and 8 to 10. Here, storing the fuel gas in a gaseous state means that the majority of the fuel gas stored in the fuel gas storage device 41 is in a gaseous state. The fuel gas is stored in a compressed state inside the fuel gas storage device 41, and the pressure of the fuel gas inside the fuel gas storage device 41 is relatively high.

[0077] According to the above configuration, the fuel gas to be supplied to the fuel cell 2 can be heated by heat exchange in the heat exchanger 43, 44, or 45 using the fuel gas as a heat medium in the fuel gas supply line 4. This allows the fuel gas to be supplied to the fuel cell 2 to be heated to a temperature suitable for the chemical reaction in the fuel cell 2 before being supplied to the fuel cell 2.

[0078] (Decompression device) In some embodiments, the above-described fuel gas storage device 41 is configured to store the fuel gas in a gaseous state, as shown in Figures 8 to 10. The above-described fuel cell system 1 further includes a pressure reducing device 46 that is provided in the fuel gas supply line 4 upstream of a heat exchanger 43, 44, or 45 that uses the fuel gas as a heat medium and is configured to reduce the pressure of the fuel gas. The pressure reducing device 46 is provided upstream of the most upstream heat exchanger among the multiple heat exchangers provided in the fuel gas supply line 4. The pressure reducing device 46 may be a pressure reducing valve or an expansion turbine as long as it is configured to reduce the pressure of the fuel gas.

[0079] According to the above configuration, the temperature of the fuel gas can be lowered by decompressing the fuel gas in the pressure reducing device 46. In this case, the temperature of the fuel gas supplied to the heat exchanger 43, 44, or 45 in the fuel gas supply line 4, which uses the fuel gas as a heat medium, can be lowered, and the oxidizing gas can be effectively cooled in the heat exchanger 43, 44, or 45 by utilizing the cold energy of the fuel gas.

[0080] In this specification, expressions expressing relative or absolute arrangement such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" not only express such an arrangement strictly, but also express a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions such as "identical," "equal," and "homogeneous" that indicate that something is in an equal state not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. Furthermore, in this specification, expressions representing shapes such as a rectangular shape or a cylindrical shape not only represent rectangular shapes or cylindrical shapes in the strict geometric sense, but also represent shapes including uneven portions, chamfered portions, etc., to the extent that the same effect can be obtained. Furthermore, in this specification, the expressions "comprise," "include," or "have" a component are not exclusive expressions that exclude the presence of other components.

[0081] The present disclosure is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0082] The contents of the above-described embodiments can be understood, for example, as follows.

[0083] 1) A fuel cell system (1) according to at least one embodiment of the present disclosure comprises: a fuel cell (2); an oxidizing gas supply line (3) for supplying oxidizing gas to the fuel cell (2); a compressor (31) provided in the oxidizing gas supply line (3) and configured to compress the oxidizing gas; a cooling medium supply line (6) for supplying a cooling medium for cooling the fuel cell (2) to the fuel cell (2); a cooling medium pump (61) provided in the cooling medium supply line (6) and configured to increase the pressure of the cooling medium; and an oxidizing gas cooler (63) configured to perform heat exchange between the cold medium flowing through the cold medium supply line (6) and the oxidizing gas compressed by the compressor (31) flowing downstream of the compressor (31) in the oxidizing gas supply line (3).

[0084] According to the above configuration 1), the oxidant gas to be supplied to the fuel cell (2) can be cooled by heat exchange in the oxidant gas cooler (63). As a result, the oxidant gas compressed in the compressor (31) and heated to a relatively high temperature (approximately 200°C) can be cooled to a temperature (approximately 60°C) suitable for the chemical reaction in the fuel cell (2) before being supplied to the fuel cell (2). The oxidant gas cooler (63) uses the cooling system of the fuel cell (2), such as the cooling medium supply line (6) and the cooling medium pump (61), to supply the cooling medium to the oxidant gas cooler (63). Therefore, dedicated lines and pumps are not required, and the structure of the fuel cell system (1) can be simplified.

[0085] 2) In some embodiments, the fuel cell system (1) described in 1) above, an exhaust gas line (5) for sending exhaust gas discharged from the fuel cell (2); a turbine (51) provided in the exhaust gas line (5) and configured to be driven by the exhaust gas; The system further includes a first heat exchanger (52) configured to exchange heat between the exhaust gas flowing downstream of the turbine (51) in the exhaust gas line (5) and the oxidizing gas flowing downstream of the compressor (31) in the oxidizing gas supply line (3).

[0086] According to the configuration 2), the oxidizing gas supplied to the fuel cell 2 can be cooled by heat exchange in the first heat exchanger 52. The exhaust gas, which has expanded in the turbine 51 and reached a relatively low temperature (approximately 10°C), is used to cool the oxidizing gas supplied to the fuel cell 2. This reduces the loss of cold energy in the cooling system of the fuel cell 2 and simplifies the structure of the fuel cell system 1.

[0087] 3) In some embodiments, the fuel cell system (1) described in 2) above, The fuel cell cooler (53) is further provided, which is configured to cool the fuel cell (2) by the exhaust gas flowing downstream of the turbine (51) in the exhaust gas line (5).

[0088] According to the configuration 3), the fuel cell 2 can be cooled in the fuel cell cooler 53. By utilizing the exhaust gas that has expanded in the turbine 51 and reached a relatively low temperature (approximately 10°C) to cool the fuel cell 2, it is possible to suppress the loss of cold energy in the cooling system of the fuel cell 2 and simplify the structure of the fuel cell system 1.

[0089] 4) In some embodiments, the fuel cell system (1) described in 1) above, an exhaust gas line (5) for sending exhaust gas discharged from the fuel cell (2); a turbine (51) provided in the exhaust gas line (5) and configured to be driven by the exhaust gas; The cooling medium supply system further includes a second heat exchanger (54) configured to exchange heat between the exhaust gas flowing downstream of the turbine (51) in the exhaust gas line (5) and the cooling medium flowing in the cooling medium supply line (6).

[0090] According to the configuration 4), the cold medium flowing through the cold medium supply line 6 can be cooled by heat exchange in the second heat exchanger 54. The cold medium is cooled by using the exhaust gas that has expanded in the turbine 51 and reached a relatively low temperature (approximately 10°C). This reduces the cold heat loss in the cooling system of the fuel cell 2 and simplifies the structure of the fuel cell system 1.

[0091] 5) In some embodiments, the fuel cell system (1) described in 1) above, an exhaust gas line (5) for sending exhaust gas discharged from the fuel cell (2); a turbine (51) provided in the exhaust gas line (5) and configured to be driven by the exhaust gas; The system further includes a third heat exchanger (55) configured to exchange heat between the exhaust gas flowing upstream of the turbine (51) in the exhaust gas line (5) and the oxidizing gas flowing downstream of the compressor (31) in the oxidizing gas supply line (3).

[0092] According to the configuration of 5), the oxidizing gas supplied to the fuel cell 2 can be cooled by heat exchange in the third heat exchanger 55. By using the exhaust gas at a relatively low temperature (about 80°C) before being introduced into the turbine 51 to cool the oxidizing gas supplied to the fuel cell 2, it is possible to suppress the loss of cold energy in the cooling system of the fuel cell 2 and simplify the structure of the fuel cell system 1.

[0093] According to the configuration of 5), the exhaust gas can be heated by heat exchange in the third heat exchanger (55) before being introduced into the turbine (51). By increasing the temperature of the exhaust gas to be introduced into the turbine (51), the amount of energy that can be recovered in the turbine (51) can be increased. In the case where the turbine (51) is connected to the compressor (31) via the rotating shaft (33), the amount of energy that can be recovered in the turbine (51) can be increased, thereby increasing the amount of assistance that the turbine (51) provides in driving (rotating) the compressor (31). This reduces the power required to drive (rotate) the compressor (31) (for example, the power consumption of the electric motor 32).

[0094] 6) In some embodiments, the fuel cell system (1) according to any one of 2) to 5) above, the compressor (31) includes an electric compressor (31A) configured to be driven by an electric motor (32) to compress the oxidizing gas; The fuel cell system (1) The air conditioning system further includes a motor cooler (56) configured to cool the electric motor (32) by the exhaust gas flowing downstream of the turbine (51) in the exhaust gas line (5).

[0095] According to the configuration 6), the electric motor (32) can be cooled in the motor cooler (56). By using the exhaust gas that has expanded in the turbine (51) and reached a relatively low temperature (approximately 10° C.) to cool the electric motor (32), it is possible to prevent the electric motor (32) from overheating and to simplify the structure of the fuel cell system (1).

[0096] 7) In some embodiments, the fuel cell system (1) described in 1) above, a fuel gas storage device (41) configured to store fuel gas; a fuel gas supply line (4) for sending the fuel gas stored in the fuel gas storage device (41) to the fuel cell (2); The system further includes a fourth heat exchanger (43) configured to exchange heat between the fuel gas flowing through the fuel gas supply line (4) and the oxidizing gas flowing upstream of the compressor (31) in the oxidizing gas supply line (3).

[0097] According to the configuration of 7) above, the oxidizing gas before being introduced into the compressor (31) is cooled by heat exchange in the fourth heat exchanger (43), thereby making it possible to lower the temperature of the oxidizing gas to be supplied to the fuel cell (2). As a result, the oxidizing gas compressed in the compressor (31) and heated to a relatively high temperature (approximately 200°C) can be cooled to a temperature (approximately 60°C) suitable for the chemical reaction in the fuel cell (2) before being supplied to the fuel cell (2). The fourth heat exchanger (43) uses the cold energy of the fuel gas before being supplied to the fuel cell (2), so that a dedicated line and pump are not required, and the structure of the fuel cell system (1) can be simplified.

[0098] According to the above configuration 7), the oxidizing gas before being introduced into the compressor (31) is cooled by heat exchange in the fourth heat exchanger (43), thereby reducing the power required to drive (rotate) the compressor (31) (for example, the power consumption of the electric motor 32).

[0099] 8) In some embodiments, the fuel cell system (1) described in 7) above, The system further includes a fifth heat exchanger (44) configured to exchange heat between the fuel gas flowing through the fuel gas supply line (4) and the oxidizing gas flowing downstream of the compressor (3) in the oxidizing gas supply line (3).

[0100] According to the configuration of 8), the oxidizing gas supplied to the fuel cell 2 can be cooled by heat exchange in the fifth heat exchanger 44. By using the cold energy of the fuel gas before being supplied to the fuel cell 2 to cool the oxidizing gas supplied to the fuel cell 2, it is possible to suppress cold energy loss in the cooling system of the fuel cell 2 and simplify the structure of the fuel cell system 1.

[0101] 9) In some embodiments, the fuel cell system (1) described in 7) above, The system further includes a sixth heat exchanger (45) configured to exchange heat between the fuel gas flowing through the fuel gas supply line (4) and the cooling medium flowing through the cooling medium supply line (6).

[0102] According to the configuration of 9), the cold medium flowing through the cold medium supply line 6 can be cooled by heat exchange in the sixth heat exchanger 45. By using the cold energy of the fuel gas before it is supplied to the fuel cell 2 to cool the cold medium, it is possible to suppress cold loss in the cooling system of the fuel cell 2 and simplify the structure of the fuel cell system 1.

[0103] 10) In some embodiments, the fuel cell system (1) described in 1) above, a fuel gas storage device (41) configured to store fuel gas; a fuel gas supply line (4) for sending the fuel gas stored in the fuel gas storage device (41) to the fuel cell (2); The system further includes a fifth heat exchanger (44) configured to exchange heat between the fuel gas flowing through the fuel gas supply line (4) and the oxidizing gas flowing downstream of the compressor (31) in the oxidizing gas supply line (3).

[0104] According to the configuration of 10), the oxidizing gas supplied to the fuel cell 2 can be cooled by heat exchange in the fifth heat exchanger 44. By using the cold energy of the fuel gas before being supplied to the fuel cell 2 to cool the oxidizing gas supplied to the fuel cell 2, it is possible to suppress cold energy loss in the cooling system of the fuel cell 2 and simplify the structure of the fuel cell system 1.

[0105] 11) In some embodiments, the fuel cell system (1) described in 1) above, a fuel gas storage device (41) configured to store fuel gas; a fuel gas supply line (4) for sending the fuel gas stored in the fuel gas storage device (41) to the fuel cell (2); The system further includes a sixth heat exchanger (45) configured to exchange heat between the fuel gas flowing through the fuel gas supply line (4) and the cold medium flowing through the cold medium supply line (6).

[0106] According to the configuration of 11), the cold medium flowing through the cold medium supply line 6 can be cooled by heat exchange in the sixth heat exchanger 45. By using the cold energy of the fuel gas before it is supplied to the fuel cell 2 to cool the cold medium, it is possible to suppress the cold heat loss in the cooling system of the fuel cell 2 and simplify the structure of the fuel cell system 1.

[0107] 12) In some embodiments, the fuel cell system (1) according to any one of 7) to 11) above, The fuel gas storage device (41) is configured to store the fuel gas in a liquid state.

[0108] According to the above configuration 12), the fuel gas to be supplied to the fuel cell (2) can be heated by heat exchange in the heat exchanger (43, 44 or 45) using the fuel gas as a heat medium in the fuel gas supply line 4. This allows the fuel gas to be vaporized before being supplied to the fuel cell (2) and heated to a temperature close to that suitable for the chemical reaction in the fuel cell (2).

[0109] 13) In some embodiments, the fuel cell system (1) according to any one of 7) to 11) above, The fuel gas storage device (41) is configured to store the fuel gas in a gaseous state.

[0110] According to the above configuration 13), the fuel gas to be supplied to the fuel cell (2) can be heated by heat exchange in the heat exchanger (43, 44 or 45) using the fuel gas as a heat medium in the fuel gas supply line 4. This allows the fuel gas to be supplied to the fuel cell (2) to be heated to a temperature suitable for the chemical reaction in the fuel cell (2) before being supplied to the fuel cell (2).

[0111] 14) In some embodiments, the fuel cell system (1) according to 13) above, The system further includes a pressure reducing device (46) that is provided in the fuel gas supply line (4) upstream of the heat exchanger (43, 44 or 45) that uses the fuel gas as a heat medium and that is configured to reduce the pressure of the fuel gas.

[0112] According to the above configuration 14), the temperature of the fuel gas can be lowered by reducing the pressure of the fuel gas in the pressure reducing device (46). In this case, the temperature of the fuel gas supplied to the heat exchanger (43, 44, or 45) in the fuel gas supply line 4, which uses the fuel gas as a heat medium, can be lowered, and the oxidizing gas can be effectively cooled in the heat exchanger (43, 44, or 45) by utilizing the cold energy of the fuel gas. [Explanation of symbols]

[0113] 1. Fuel cell system 2 fuel cell 3. Oxidizing gas supply line 4. Fuel gas supply line 5 Exhaust gas line 6 Cooling medium supply line 20 power generation cells 21 Air electrode 22 Fuel electrode 23 Electrolyte membrane 31 Compressor 31A Electric Compressor 32 Electric motor 41 Fuel gas storage device 42 First fuel gas flow control valve 43 4th heat exchanger 44 5th heat exchanger 45 6th heat exchanger 46 Pressure reducing device 51 Turbine 52 1st heat exchanger 53 Fuel cell cooler 54 Second heat exchanger 61 Cooling medium pump 62 Electric motor 63 Oxidizing gas cooler 64 Radiator

Claims

1. A fuel cell; an oxidizing gas supply line for supplying oxidizing gas to the fuel cell; a compressor provided in the oxidizing gas supply line and configured to compress the oxidizing gas; a cooling medium supply line for supplying a cooling medium for cooling the fuel cell to the fuel cell; a cooling medium pump provided in the cooling medium supply line and configured to increase the pressure of the cooling medium; an oxidizing gas cooler configured to perform heat exchange between the cold medium flowing through the cold medium supply line and the oxidizing gas compressed by the compressor flowing downstream of the compressor in the oxidizing gas supply line, a fuel gas storage device configured to store fuel gas; a fuel gas supply line for sending the fuel gas stored in the fuel gas storage device to the fuel cell; a fourth heat exchanger configured to exchange heat between the fuel gas flowing through the fuel gas supply line and the oxidizing gas flowing upstream of the compressor in the oxidizing gas supply line, Fuel cell system.

2. an exhaust gas line for sending exhaust gas discharged from the fuel cell; a turbine provided in the exhaust gas line and configured to be driven by the exhaust gas; a first heat exchanger configured to perform heat exchange between the exhaust gas flowing downstream of the turbine in the exhaust gas line and the oxidizing gas flowing downstream of the compressor in the oxidizing gas supply line, The fuel cell system according to claim 1 .

3. a fuel cell cooler configured to cool the fuel cell by the exhaust gas flowing downstream of the turbine in the exhaust gas line, The fuel cell system according to claim 2 .

4. an exhaust gas line for sending exhaust gas discharged from the fuel cell; a turbine provided in the exhaust gas line and configured to be driven by the exhaust gas; a second heat exchanger configured to perform heat exchange between the exhaust gas flowing downstream of the turbine in the exhaust gas line and the cold medium flowing in the cold medium supply line, The fuel cell system according to claim 1 .

5. an exhaust gas line for sending exhaust gas discharged from the fuel cell; a turbine provided in the exhaust gas line and configured to be driven by the exhaust gas; a third heat exchanger configured to exchange heat between the exhaust gas flowing in the exhaust gas line on an upstream side of the turbine and the oxidizing gas flowing in the oxidizing gas supply line on a downstream side of the compressor, The fuel cell system according to claim 1 .

6. the compressor includes an electric compressor configured to be driven by an electric motor to compress the oxidizing gas; The fuel cell system includes: a motor cooler configured to cool the electric motor by the exhaust gas flowing downstream of the turbine in the exhaust gas line, 5. The fuel cell system according to claim 2.

7. further comprising a fifth heat exchanger configured to exchange heat between the fuel gas flowing through the fuel gas supply line and the oxidizing gas flowing on a downstream side of the compressor in the oxidizing gas supply line; The fuel cell system according to claim 1 .

8. a sixth heat exchanger configured to exchange heat between the fuel gas flowing through the fuel gas supply line and the cooling medium flowing through the cooling medium supply line; The fuel cell system according to claim 1 .

9. The fuel gas storage device is configured to store the fuel gas in a liquid state. The fuel cell system according to claim 1 .

10. The fuel gas storage device is configured to store the fuel gas in a gaseous state. The fuel cell system according to claim 1 .

11. a pressure reducing device that is provided in the fuel gas supply line upstream of the heat exchanger that uses the fuel gas as a heat medium and that is configured to reduce the pressure of the fuel gas; The fuel cell system according to claim 10.

Images