JPH06203846A - Reaction gas compression system utilizing regenerative braking - Google Patents

Abstract

PURPOSE:To operate a fuel cell to yield high outputs by utilizing regenerative braking energy in compressing the reaction gas of the fuel cell, and storing the energy in gas so that it is used in operations such as separation and refinement. CONSTITUTION:When an automobile (FC-EV) carrying a hydrogen-oxygen fuel call is braked at some speed, a reaction gas compression system 01 stops the supply of power from a fuel cell 31 to a drive motor 34 and releases the clutch 35 to open a valve 17a and close a valve 17c. Then methanol gas from a reformer 15 is forcibly fed to a fuel-gas separator 12 by a force feed pump 11. The separator 12 separates H2 from CO2 and the H2 is stored in a hydrogen tank 23. Then air A is allowed to pass through a valve 27a and O2 is separated therefrom by an oxidizer-gas separator 22 and stored in an oxygen tank 23. Therefore the concentrations of H2 and O2 for supply to the fuel cell are increased, so that high-output operation is made possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reaction gas compression system for a fuel cell using regenerative braking in a vehicle equipped with a fuel cell.

[0002]

2. Description of the Related Art Conventionally, in a vehicle equipped with a hydrogen-oxygen type fuel cell as a power source (hereinafter referred to as "FC-EV"), hydrogen is loaded in the form of a metal hydride and regenerative braking is applied. Water is electrolyzed by the electric power generated by the above, the hydrogen obtained by this is led to the above metal hydride, and the obtained oxygen is sent to the fuel cell as it is for storage and reuse. A system has been proposed (Japanese Patent Laid-Open No. 50-15).
8016, JP-A-50-158017).
It should be noted that when the brake pedal is depressed during braking of the vehicle, the changeover switch incorporated in the brake mechanism is activated, and the drive motor acts as a generator to generate electric power to apply braking action to the vehicle. This is known as regenerative braking. By the way, in the reaction gas generation system 50 based on the regenerative braking, as shown in FIG.
Further, hydrogen H ₂ generated from the metal hydride and air (oxygen O ₂ ) A from the atmosphere are supplied from the conduits 59a and 59b, respectively. In addition, as water consumed in the water electrolysis device 55, water H ₂ O generated in the fuel cell 51 is used as a conduit 59.
Introduced by c. The decomposed hydrogen H ₂ generated in the water electrolyzer 55 is pressure-fed from the conduit 59d to the metal hydride storage tank 57 by the hydrogen compressor 56, stored in the form of gas or metal hydride, and supplied to the fuel cell 51 as necessary. It On the other hand, the decomposed oxygen O ₂ is introduced into the fuel cell 51 through the conduits 59e and 59b and used as an oxidant. Reference numerals 52 and 54 denote brake pedals and drive motors, which are connected to the controller 53 by lead wires, respectively, and generate regenerative braking. The metal hydride releases hydrogen H ₂ by heating it to a predetermined temperature, but this heating can be performed by an appropriate method, and the heating is controlled, for example, by detecting the internal pressure of the metal hydride storage tank 57. The operation is performed by a command from the controller 53 by operating the pressure detector 58 or the like.

[0003]

However, in the above-mentioned conventional reaction gas generation system by regenerative braking, the electric power obtained by regenerative braking is used to electrolyze water to effectively use the braking energy that would otherwise be a loss. However, it is possible to refuel by using it to supply the pure reaction gas during high-power operation or low load, and high load when high power is required such as when starting or accelerating.
It is impossible to operate the fuel cell in detail, such as realizing high-efficiency operation.

The present invention has been made against the background of such conventional problems. The regenerative braking energy is used for compressing a reaction gas of a fuel cell to store energy in the gas and perform work such as separation and purification. Another object of the present invention is to provide a reaction gas compression system by regenerative braking that enables high output and high efficiency operation by supplying pure reaction gas regardless of high output and low load.

[0005]

DISCLOSURE OF THE INVENTION The present invention vaporizes methanol and water in a vehicle which is driven by a hydrogen-oxygen fuel cell to drive a drive motor through a controller for regenerative braking by the operation of a brake. From the reformer that inhales through the device, the pressure pump connected to the transmission,
A return route that supplies hydrogen to the fuel cell by the normal route via the fuel gas separator, the check valve, the hydrogen tank and the back pressure valve, or via the bypass route by the bypass conduit, and has another back pressure valve from the fuel cell. A system for concentrating hydrogen in methanol reformed gas by regenerative braking, in which unreacted gas is guided to the reformer by means of a refueling system, and an oxidant gas separator from a pressure feed pump connected to the transmission, and a reverse compressor Oxygen is supplied to the fuel cell by a normal route through a stop valve, an oxygen tank and a back pressure valve or by a bypass route by a bypass conduit, and the unreacted gas is rectified from the fuel cell by a reflux route having another back pressure valve. The reaction gas compression system by regenerative braking, which is characterized by being combined with an oxygen concentration system in the air by regenerative braking configured to lead to a quality device. It is intended to provide a Temu.

[0006]

In the reaction gas compression system by regenerative braking according to the present invention having the above-mentioned structure, when the FC-EV is braked from a certain speed, the power supply from the fuel cell to the drive motor is stopped and the clutch is disengaged to bypass the bypass conduit. Both pressure pumps became compression pumps by closing, and in the hydrogen concentration system in methanol reformed gas, the hydrogen / carbon dioxide mixed gas from the reformer was compressed and subsequently separated by the gas separator. Hydrogen is stored in the hydrogen tank. On the other hand, in the oxygen concentration system in air, the oxygen in the atmosphere is sent under pressure and separated by the gas separator is stored in the oxygen tank. The supply of the reaction gas to the fuel cell at the time of low load uses the pressure pump as a gas supply pump by closing the normal route and passing through the bypass route. When high output is required during high load / high efficiency operation, starting / accelerating, etc., the reaction gas pressure is increased via the bypass route along the normal route to prevent fuel cell voltage drop during high current density operation. Achieve high load operation. The reaction gas and the unreacted gas that have finished working in the fuel cell are guided to the combustion section in the reformer through the reflux route.
Further, unnecessary carbon dioxide and nitrogen separated by the respective gas separators are directly removed from the gas separators to the outside.

[0007]

Embodiments of the present invention will now be described with reference to the drawings, but the present invention is not limited to these embodiments. The FC-EV to which the present invention is applied is a brake pedal 3
The wheel drive device 30 that sends power from the hydrogen-oxygen type fuel cell 31 to the drive motor 34 connected to the clutch 35 via the controller 33 that performs regenerative braking by the operation of 2.
And the transmission 41, the propulsion shaft 42, which are connected to the clutch 35,
The driving force transmission device 40 includes a differential gear 43, a drive shaft 44, and a rear wheel 45.

By the way, in the reaction gas compression system 01 by regenerative braking of the present embodiment, as shown in FIG. 1, the hydrogen concentration system 10 in the methanol reformed gas and the oxygen concentration system 20 in the air drive the wheels. It is configured in combination with the device 30. In the hydrogen concentration system 10 in the reformed gas of methanol, a vaporizer 16 for heating the supplied methanol M and water W by a heater and a reformer 15 for the methanol M are provided.
A pressure feed pump 11 for compressing and supplying the methanol reformed gas (CO ₂ , H ₂ ) by regenerative braking, a valve 17a,
Fuel gas separator for separating and concentrating hydrogen H ₂ used for fuel cell reaction into pure hydrogen by gas separation methods such as adsorption separation and membrane separation of hydrogen, carbon dioxide and a trace amount of carbon monoxide in methanol reformed gas 12, the check valve 18, the hydrogen tank 13, the back pressure valve 19a, and the valve 17b are connected to form a normal route 10a reaching the fuel cell 31. In addition, the valve 17c is connected from the pressure pump 11 to the fuel cell 31.
A bypass route 10b is also provided having a bypass conduit 14 connected via the. Further, the fuel cell 31
The hydrogen H ₂ and the unreacted H _{2 that} have finished their action in step 1 are equipped with a reflux route 10c that is piped so as to be guided to the reformer 15 via the back pressure valve 19b.

In the air oxygen enrichment system 20, a pressure feed pump 21 for compressing and supplying the inhaled air A in the atmosphere, a valve 27a, and oxygen and nitrogen in the air compressed by regenerative braking are separated by adsorption or membrane separation. An oxidant gas separator 22 for separating (separation / concentration of oxygen) by a gas separation method, a check valve 28, an oxygen tank 23, a back pressure valve 29a, and a valve 2
Normal route 20 connecting to 7b and reaching fuel cell 31
a is formed. Further, a bypass conduit 24 connected from the pressure pump 21 to the fuel cell 31 via a valve 27c.
A bypass route 20b having the above is also provided. Further, oxygen O ₂ and unreacted O _{2 which} have finished working in the fuel cell 31 are provided with a reflux route 20c which is piped so as to be guided to the reformer 15 via the back pressure valve 29b.

With the above-mentioned structure, in the reaction gas compression system 01 by regenerative braking of this embodiment, in order to concentrate the hydrogen H ₂ in the methanol reformed gas by regenerative braking, a certain speed of FC-EV is required. When the brake is applied, the power supply from the fuel cell 31 to the drive motor 34 is stopped, the valve 17a is opened with the clutch 35 disengaged, and the valve 17c is closed, so that the pressure pump 11 becomes a compression pump and the reformer 15 Hydrogen H ₂ and carbon dioxide CO _{2 from}
The mixed gas of and is sent under pressure to the fuel gas separator 12. Therefore, the separator 12 has a predetermined pressure (6 to 7 kg /
cm ² · G) hydrogen H ₂ and carbon dioxide CO ₂ are separated, and the separated hydrogen H ₂ is sent to the hydrogen tank 13 and stored by the check valve 18 blocking the reverse flow. on the other hand,
The separated carbon dioxide CO ₂ is excluded to the outside.

When the clutch 35 is disengaged, the valve 27a opens and the valve 27c closes when the clutch 35 is disengaged, so that the pressure pump 21 serves as a regenerative braking source and the compression pump 21 as a regenerative braking source. The air A in the atmosphere is compressed and pressure-fed to the oxidant gas separator 22, and the separator 22 causes a predetermined pressure (6 to 7 kg / cm ₂ ·
G) is separated into oxygen O ₂ and nitrogen N _2, and the nitrogen N ₂
Are excluded to the outside. On the other hand, the separated oxygen O ₂ is sent to the oxygen tank 23 and stored by being blocked by the check valve 28 from backflow. Brake pedal 3 when the vehicle is stopped
The above-mentioned valve opening / closing operation does not occur in the stepping-in operation of 2.

The reaction gas supply to the fuel cell at low load is
In the case of fuel gas, in the hydrogen concentration system 10 in the reformed methanol gas, the valves 17a and 17b are closed, and the valve 17
The pressure feed pump 11 is used for supply in the state where the bypass route 10b in which c is opened is used, and the gas is supplied to the fuel cell in the state of H ₂ CO ₂ mixed gas. The fuel gas pressure at this time is determined by the gas supply amount of the pressure pump 11 and the opening degree of the back pressure valve 19b. The pressure pump 11 has both functions of gas supply and gas compression. That is, when the back pressure valve is fully opened, it functions as a gas supply pump that creates a flow through the normal route 10a and the reflux route 10c, but when the back pressure valve is closed to a certain setting, it changes to a gas compression pump. On the other hand, in the case of the oxidant gas, in the oxygen concentration system 20 in the air, the pressure feed pump 2 is used with the bypass route 20b in which the valves 27a and 27b are closed and the valve 27c is opened.
1 is used for supply, and oxygen O ₂ is supplied to the fuel cell 31 in a state of being included in the air A. The oxidant gas pressure at this time is determined by the gas supply amount of the pressure pump 21 and the opening degree of the back pressure valve 29b. The pressure pump 21 has both a gas supply function and a gas compression function. That is, when the back pressure valve is fully opened, it functions as a gas supply pump that creates a flow through the normal route 20a and the return route 20c, but when the back pressure valve is closed to a certain setting, it changes to a gas compression pump.

When high output such as starting and acceleration is required during high load and high efficiency operation, the hydrogen concentration system 10 described above is used.
In the state of the normal route 10a in which the valve 17c is closed and the valve 17b is opened, the hydrogen pressure in the fuel gas is increased to prevent the voltage drop of the fuel cell 31 during high current density operation (pressure increase effect by pressure gain). It is possible to realize high load operation. At this time, hydrogen separation is also performed with the valve 17a open. Since the pressure feed pump 11 is operating even under a high load, when the valve 17a is opened while the valve 17c is closed, gas pressure rise occurs between the pressure feed pump 11 and the fuel gas separator 12 and the pressure is 6 to 7 kg / cm ^2. When G is reached, hydrogen can be separated. On the other hand, in the oxygen concentrating system 20, the oxygen pressure in the oxidant gas can be increased with the valve 27c open and the valve 27b closed to realize the high load operation as described above. At this time, oxygen concentration is also performed at the same time in the state of the normal route 10a with the valve 27a opened.

When the fuel cell 31 is activated and the amount of pure reaction gas is insufficient, the system is activated by the electric power of the auxiliary secondary battery to start FC-EV. Since the hydrogen-oxygen fuel cell unit cell itself can be started even at room temperature, it is necessary to supply energy at the time of start-up to supply the fuel gas and the oxidant gas to the fuel cell stack and the reformer. Is the start of. If hydrogen is present in the hydrogen tank 13, the fuel cell 31 can be started by the hydrogen, but if not, the next step S is required. S1 Reforming a specific reforming tube in the reformer 15 with an auxiliary secondary battery by a heater S2 Reheating the vaporizer 16 in front of the reformer 15 with a heater S3 Supplying methanol M and water W to the reformer 15 Then, the reforming is started. S4 The drive motor 34 is rotated by the secondary battery, and the clutch 35 is connected. S5 The power of the drive motor 34 is switched so as to be transmitted only to the pressure pumps 11 and 21 in the transmission 41 (fuel cell 31 startup). S6 The supply source of the electric energy in each of the above steps S1 to 5 is gradually switched from the auxiliary secondary battery to the fuel cell 31. Although the embodiment of the present invention has been described above, the present invention is not necessarily limited to this embodiment, and a design change and the like without departing from the scope of the invention are included in the present invention.

[0015]

The reaction gas compression system by regenerative braking of the present invention uses regenerative braking energy to compress the reaction gas of the fuel cell to store energy in the gas and perform work such as separation and purification. The partial pressure of hydrogen and oxygen supplied to the fuel cell is increased by compressing the reaction gas of the fuel cell by regenerative braking, that is, air / oxygen that is the oxidant gas and methanol reformed hydrogen that is the fuel gas. The high output operation of the fuel cell can be performed including the above. In addition, hydrogen, carbon dioxide and a trace amount of carbon monoxide in the methanol reformed gas compressed by regenerative braking, and oxygen and nitrogen in the air are used for the fuel cell reaction by gas separation methods such as adsorption separation and membrane separation. By separating and concentrating hydrogen and oxygen, respectively, pure hydrogen and pure oxygen can be supplied to the fuel cell, and high output operation of the fuel cell can be performed, including measures for partial load. Furthermore, since the unreacted gas is returned to the reformer for use, the gas utilization rate is improved. It should be noted that hydrogen in the methanol reformed gas compressed and separated by regenerative braking and oxygen in the air are boosted and stored by regenerative braking and supplied to the fuel cell at high pressure to support high power operation. You can

[Brief description of drawings]

FIG. 1 is a system diagram of a reaction gas compression system by regenerative braking according to an embodiment of the present invention.

FIG. 2 is a system diagram of a conventional reaction gas generation system by regenerative braking.

[Explanation of symbols]

 01 Reaction gas compression system by regenerative braking 10 Hydrogen concentration system in methanol reformed gas 10a Normal route 10b Bypass route 10c Reflux route 11 Pressure feed pump 12 Fuel gas separator 13 Hydrogen tank 14 Bypass conduit 15 Reformer 16 Vaporizer 18 Reverse Stop valve 19a Back pressure valve 19b Back pressure valve 20 Oxygen enrichment system in air 20a Normal route 20b Bypass route 20c Reflux route 21 Pressure pump 22 Oxidizer gas separator 23 Oxygen tank 24 Bypass conduit 28 Check valve 29a Back pressure valve 29b Back pressure valve 31 Fuel cell 32 Brake pedal 33 Controller 34 Drive motor 41 Transmission M Methanol W Water A Air

Front page continuation (72) Inventor Hideo Kato 1-4-1 Chuo 1-4-1, Wako-shi, Saitama Honda R & D Co., Ltd.

Claims (1)

[Claims] 1. A reformer in which methanol and water are sucked in through a vaporizer in a vehicle that runs by sending power from a hydrogen-oxygen fuel cell to a drive motor through a controller that performs regenerative braking by operating a brake. From the vessel
Pressure pump connected to transmission, fuel gas separator, check valve,
Hydrogen is supplied to the fuel cell by the normal route via the hydrogen tank and the back pressure valve or by the bypass route by the bypass conduit, and the unreacted gas is fed from the fuel cell to the reformer by the reflux route having another back pressure valve. A hydrogen concentration system in the methanol reformed gas by regenerative braking that is configured to lead, and an oxidant gas separator, a check valve, an oxygen tank and a back pressure valve from a pressure-feeding pump connected to the transmission that sucks and compresses air and supplies it. Regenerative braking configured to supply oxygen to the fuel cell via the normal route via the bypass conduit or via the bypass route via the bypass conduit, and to guide the unreacted gas from the fuel cell to the reformer via the reflux route with another back pressure valve. The reaction gas compression system by regenerative braking characterized by being combined with the oxygen concentration system in the air.