JP5665684B2 - Fuel cell system - Google Patents

Description

  The present invention includes a power generation cell having an electrolyte membrane / electrode structure in which a cathode electrode and an anode electrode are provided on both sides of an electrolyte membrane, and is supplied to an oxidant gas supplied to the cathode electrode and the anode electrode. The present invention relates to a fuel cell system including a fuel cell that generates electricity by an electrochemical reaction of fuel gas.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure (MEA) provided with an anode electrode and a cathode electrode on both sides of an electrolyte membrane made of a polymer ion exchange membrane is sandwiched between a pair of separators. Yes.

  In the fuel cell, a fuel gas passage for supplying fuel gas to an anode electrode is usually formed between one separator and the electrolyte membrane / electrode structure, and the other separator and the electrolyte membrane / electrode are formed. An oxidant gas passage for supplying an oxidant gas to the cathode electrode is formed between the structure and the structure. Furthermore, a cooling medium flow path for flowing a cooling medium in the electrode range is formed between the separators constituting each fuel cell and adjacent to each other.

  This type of fuel cell may be mounted in a fuel cell box, particularly when mounted on a fuel cell electric vehicle. At that time, a fuel cell chamber for accommodating the fuel cell is formed in the fuel cell box, and a ventilation device for ventilating the fuel cell chamber is used. For example, when the ventilator detects that hydrogen has entered from the hydrogen line of the fuel cell, the ventilator has a function of discharging the hydrogen to the outside of the fuel cell box by a ventilation fan.

  In addition, in-vehicle fuel cells, there are cases where a fuel cell is mounted in a limited space such as under a vehicle body floor or a front box as a fuel cell chamber. For this reason, in the space where the fuel cell is arranged, that is, in the fuel cell room, it is necessary to ventilate similarly to the inside of the fuel cell box.

  Therefore, for example, a fuel cell box ventilation device disclosed in Patent Document 1 is known. As shown in FIG. 4, the fuel cell box ventilator includes a three-way valve 1, a ventilation pipe 2, a ventilation fan 3, a discharge port 4, a hydrogen detection sensor 5, and a control device 6.

  Then, when hydrogen inside the fuel cell box B is detected by the hydrogen detection sensor 5, the air supplied from the supercharger 7 to the fuel cell V by the three-way valve 1 is exhausted from the exhaust pipe 2 according to the detected value. To the fuel cell box B.

JP 2003-132916 A

  However, in Patent Document 1 described above, when power generation by the fuel cell V is continued while ventilation processing is performed by the fuel cell box ventilation device, the three-way valve 1 has an air flow path on the power generation side, that is, the fuel cell V. The air flow rate supplied to is reduced.

  For example, in this type of three-way valve 1, the air flow rate distributed to the fuel cell V and the ventilation pipe 2 becomes the same amount, which may affect the running of the fuel cell electric vehicle.

  An object of the present invention is to solve this kind of problem, and to provide a fuel cell system that has a simple configuration, eliminates the need for a large three-way valve, and can ensure a desired operation state. And

  The present invention includes a power generation cell having an electrolyte membrane / electrode structure in which a cathode electrode and an anode electrode are provided on both sides of an electrolyte membrane, and is supplied to an oxidant gas supplied to the cathode electrode and the anode electrode. The present invention relates to a fuel cell system including a fuel cell that generates power by an electrochemical reaction of fuel gas, a fuel cell box in which the fuel cell is accommodated, and an oxidant gas supply device that supplies the oxidant gas to the fuel cell. is there.

  In the fuel cell system, the oxidant gas supply device branches from the compressor, the oxidant gas supply path connected to the compressor and an oxidant gas supply port of the fuel cell, and the oxidant gas supply path. A cooling path for supplying an oxidant gas as cooling air to the compressor; and a ventilation path for cooling the compressor and supplying the cooling air discharged from the compressor as ventilation air into the fuel cell box. ing.

Then, the oxidizing gas supply passage, the intercooler is disposed downstream of the compressor, and the is disposed hydrothermal replaceable humidifier downstream of the intercooler Rutotomoni, cooling passage, and the intercooler said It branches out from between the humidifier.

  Furthermore, in this fuel cell system, it is preferable that the ventilation path is provided with an adjustment valve for adjusting the ventilation air flow rate.

  In the present invention, a part of the oxidant gas discharged from the compressor to the oxidant gas supply path is supplied as cooling air to the compressor through the cooling path and then ventilated into the fuel cell box through the ventilation path. It is supplied as air for use.

  For this reason, normally, after the compressor is cooled, the used cooling air discharged to the atmosphere can be further effectively used as ventilation air. Thereby, the efficiency fall of a fuel cell system can be suppressed as much as possible. In addition, a large three-way valve or the like can be eliminated, and a desired operation state can be ensured with an economical and lightweight configuration.

It is a schematic block diagram of a fuel cell system that are related to the present invention. 1 is a schematic configuration diagram of a fuel cell system according to a first embodiment of the present invention. It is a schematic block diagram of the fuel cell system which concerns on the 2nd Embodiment of this invention. It is a schematic explanatory drawing of the fuel cell box ventilation apparatus currently disclosed by patent document 1. FIG.

As shown in FIG. 1, the fuel cell system 10 that relate to the present invention, for example, constitute a vehicle fuel cell system mounted on a fuel cell electric fuel cell vehicle such as an automobile (not shown).

  The fuel cell system 10 includes a fuel cell 14 in which a plurality of power generation cells 12 are stacked (stacked) in a horizontal direction or a gravitational direction, and the fuel cell 14 is accommodated in a fuel cell box 15. In the fuel cell 14, an electrolyte membrane / electrode structure (MEA) 16 is sandwiched between a cathode separator 18 and an anode separator 20. The electrolyte membrane / electrode structure 16 includes, for example, a solid polymer electrolyte membrane 22 in which a perfluorosulfonic acid thin film is impregnated with water, and a cathode electrode 24 and an anode electrode 26 sandwiching the solid polymer electrolyte membrane 22. Prepare.

  The cathode electrode 24 and the anode electrode 26 are formed of a gas diffusion layer made of carbon paper or the like, and an electrode catalyst formed by uniformly applying porous carbon particles carrying a platinum alloy on the surface of the gas diffusion layer. And having a layer. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 22.

  An oxidant gas passage 28 is formed on the surface of the cathode separator 18 facing the electrolyte membrane / electrode structure 16. A fuel gas passage 30 is formed on the surface of the anode separator 20 facing the electrolyte membrane / electrode structure 16. A cooling medium passage (not shown) is formed between the cathode separator 18 and the anode separator 20 adjacent to each other.

  An oxidant gas supply device 32 is connected to the fuel cell 14. The oxidant gas supply device 32 includes an air pump 34. As the air pump 34, for example, a pump having internal components such as a Rishorum type or a turbine type, in particular, an air bearing that rotates at high speed is used, and a compressor 38 is integrated with a motor 36 including the air bearing.

  One end of an oxidant gas supply path 40 is connected to the air pump 34. The other end of the oxidant gas supply path 40 is connected to the fuel cell 14 and communicates with the inlet (oxidant gas supply port) side of the oxidant gas path 28.

  One end of an oxidant gas discharge passage 42 is connected to the fuel cell 14 in communication with the outlet side of the oxidant gas passage 28. The other end of the oxidant gas discharge path 42 is connected to the humidifier 44, while the oxidant gas supply path 40 is connected to the humidifier 44. The oxidant gas flowing through the oxidant gas supply path 40 exchanges moisture and heat with the used highly humidified and high-temperature oxidant exhaust gas flowing through the oxidant gas discharge path 42.

  An intercooler 46 is disposed in the middle of the oxidant gas supply path 40, and a cooling path 48 is branched from the upstream side of the intercooler 46. The cooling path 48 is a cooling air supply path for cooling the air pump 34, more specifically, the motor 36 (and a bearing (not shown)) constituting the air pump 34.

  Connected to the motor 36 is a ventilation path 50 for cooling the air pump 34 (substantially the motor 36) and supplying the cooling air discharged from the air pump 34 as ventilation air into the fuel cell box 15. Is done. The ventilation path 50 is opened to the fuel cell chamber 52 in the fuel cell box 15.

  The fuel cell 14 is disposed in a fuel cell chamber 52 formed in the fuel cell box 15. The fuel cell box 15 houses a fuel cell 14 and a hydrogen detection sensor 54 for detecting the hydrogen concentration. The hydrogen detection sensor 54 is disposed on the upper end side of the fuel cell chamber 52. An exhaust pipe 56 is connected to the fuel cell box 15 on the lower side of the wall surface.

  Operation of the fuel cell system 10 is controlled by the control unit 58. Although not shown, the fuel cell 14 is connected with a fuel gas supply device and a cooling medium supply device. The fuel gas supply device includes, for example, an ejector, a hydrogen circulation pump, a pressure reducing valve, a shutoff valve, and the like, and may be accommodated in the fuel cell box 15.

  The operation of the fuel cell system 10 configured as described above will be described below.

  First, during normal travel of a fuel cell electric vehicle (not shown) on which the fuel cell system 10 is mounted, the oxidant gas supply device 32 operates from the oxidant gas supply path 40 to the fuel cell under the drive action of the air pump 34. The oxidant gas (air) is supplied to the oxidant gas passages 14. On the other hand, in a fuel gas supply device (not shown), fuel gas (hydrogen gas) is supplied to the fuel gas passage 30 of the fuel cell 14 from a high-pressure hydrogen tank or the like.

  Accordingly, in each power generation cell 12, the oxygen in the oxidant gas supplied to the cathode electrode 24 and the hydrogen in the fuel gas supplied to the anode electrode 26 react electrochemically to generate power. For this reason, electric power is supplied from the fuel cell 14 to a travel motor (not shown), and the fuel cell electric vehicle travels.

  The oxidant gas discharged from the fuel cell 14 is supplied from the oxidant gas discharge path 42 to the humidifier 44 and then released to the outside. For this reason, the oxidant gas flowing through the oxidant gas supply path 40 is supplied to the fuel cell 14 after being humidified and heated.

In this case, the oxidation agent gas supply apparatus 32, a portion of the oxidant gas discharged from the air pump 34 to the oxidizing gas supply passage 40 is introduced into the motor 36 constituting the air pump 34 through the cooling passage 48 Is done. For this reason, the motor 36 is cooled well by the cooling air, while the used cooling air is led out from the motor 36 to the ventilation path 50 as ventilation air.

  The ventilation air flows through the ventilation path 50 and is supplied to the fuel cell chamber 52 of the fuel cell box 15. Therefore, the ventilation air and the residual hydrogen are discharged to the outside through the exhaust pipe 56, and the hydrogen concentration in the fuel cell chamber 52 decreases.

  In this way, a part of the oxidant gas discharged from the air pump 34 to the oxidant gas supply path 40 is supplied as cooling air to the air pump 34 through the cooling path 48, and then passes through the ventilation path 50 to form fuel. The battery box 15 is supplied as ventilation air.

  For this reason, normally, after cooling the air pump 34 (mainly the motor 36), the used cooling air discharged to the atmosphere can be effectively used as ventilation air, which reduces the efficiency of the fuel cell system 10. It can be suppressed as much as possible. Moreover, it is possible to eliminate the need for a large three-way valve and the like, and it is possible to obtain an effect that a desired operation state can be ensured with an economical and lightweight configuration.

FIG. 2 is a schematic configuration diagram of the fuel cell system 70 according to the first embodiment of the present invention. Note that the fuel cell system 10 same components and are denoted by the same reference numerals, and detailed description thereof will be omitted.

  The fuel cell system 70 includes an oxidant gas supply device 72. In the oxidant gas supply device 72, a cooling path 74 is branched from the downstream of the intercooler 46, more specifically, between the intercooler 46 and the humidifier 44, along the oxidant gas supply path 40. . The cooling path 74 supplies cooling air to the motor 36 of the air pump 34.

In the first embodiment configured as described above, a part of the oxidant gas discharged from the air pump 34 to the oxidant gas supply path 40 is cooled by the intercooler 46, and then passes through the cooling path 74. It is introduced into a motor 36 constituting the air pump 34.

Accordingly, since the motor 36 is supplied with relatively low-temperature cooling air that has passed through the intercooler 46, the motor 36 can be cooled more efficiently. Used cooling air is derived as ventilation air. Thereby, the effect that a desired driving | running state can be ensured with an economical and lightweight structure is acquired.

FIG. 3 is a schematic configuration diagram of a fuel cell system 80 according to the second embodiment of the present invention. Note that the fuel cell system 10 and 70 the same components as are denoted by the same reference numerals, and detailed description thereof will be omitted.

  The fuel cell system 80 includes an oxidant gas supply device 82. In the oxidant gas supply device 82, a valve 84 that adjusts or shuts off the flow rate of the ventilation air is arranged in series (or in parallel) along the ventilation path 50.

For this reason, in the second embodiment, for example, when the flow rate of ventilation air required in the fuel cell box 15 is small, the opening degree of the valve 84 can be reduced. On the other hand, when the hydrogen detection sensor 54 detects a hydrogen concentration exceeding a specified value in the fuel cell chamber 52, a large flow rate of ventilation air is supplied to the fuel cell chamber 52 by opening the valve 84. It becomes possible.

As a result, in the second embodiment, the same effects as those of the fuel cell systems 10 and 70 described above can be obtained, and the flow rate of the ventilation air supplied to the fuel cell box 15 can be precisely adjusted in accordance with changes in the situation. There is an advantage that it can be adjusted.

DESCRIPTION OF SYMBOLS 10, 70, 80 ... Fuel cell system 12 ... Power generation cell 14 ... Fuel cell 15 ... Fuel cell box 16 ... Electrolyte membrane and electrode structure 22 ... Solid polymer electrolyte membrane 24 ... Cathode electrode 26 ... Anode electrode 28 ... Oxidant gas Passage 30 ... Fuel gas passages 32, 72, 82 ... Oxidant gas supply device 34 ... Air pump 36 ... Motor 38 ... Compressor 40 ... Oxidant gas supply passage 42 ... Oxidant gas discharge passage 44 ... Humidifier 46 ... Intercooler 48, 74 ... Cooling path 50 ... Ventilation path 52 ... Fuel cell chamber 54 ... Hydrogen detection sensor 56 ... Exhaust piping 58 ... Control unit 84 ... Valve

Claims (2)

A power generation cell having an electrolyte membrane / electrode structure in which a cathode electrode and an anode electrode are provided on both sides of the electrolyte membrane, and an oxidant gas supplied to the cathode electrode and an electric power of a fuel gas supplied to the anode electrode A fuel cell that generates electricity through a chemical reaction;
A fuel cell box in which the fuel cell is housed;
An oxidant gas supply device for supplying the oxidant gas to the fuel cell;
A fuel cell system comprising:
The oxidant gas supply device includes a compressor,
An oxidant gas supply path connected to the compressor and an oxidant gas supply port of the fuel cell;
A cooling path branched from the oxidant gas supply path and supplying the oxidant gas as cooling air to the compressor;
A ventilation path for cooling the compressor and supplying the cooling air discharged from the compressor as ventilation air into the fuel cell box;
Equipped with a,
In the oxidant gas supply path, an intercooler is disposed downstream of the compressor, and a hot water exchange type humidifier is disposed downstream of the intercooler.
The cooling passage, the fuel cell system characterized that you branched from between said humidifier and said intercooler. In claim 1 Symbol placement of the fuel cell system, wherein the ventilation passage, the fuel cell system and providing a regulating valve for adjusting the ventilation air flow rates.

Images