CN1268024C - Compressor-expander system of fuel battery - Google Patents

Abstract

A compressor-expander system for fuel cells, which is applicable to both low-pressure fuel cell systems and high-pressure fuel cell systems, and includes: a primary compressor and a secondary compressor for compressing air, one of which supplies the system with A power motor and an energy recovery expander are connected through pipelines, solenoid valves and electromagnetic clutches. Through the action of electromagnetic valve and electromagnetic clutch, for low-voltage fuel cell systems, the motor drives the primary compressor, the compressed air is directly supplied to the fuel cell stack, and the air discharged from the fuel cell stack is directly discharged into the atmosphere; for high-voltage fuel cell systems, the air After being compressed by the primary compressor, it continues to enter the secondary compressor for compression, and then it is supplied to the fuel cell stack. The air discharged from the fuel cell stack enters the expander to expand and perform work, and then is discharged into the atmosphere.

Description

Compressor-expander system for fuel cell

technical field

The invention belongs to the technical field of compressors, in particular to a fuel cell compressor-expander system using compressed air as an oxidant.

Background technique

A fuel cell is an electrochemical device that uses the action of a fuel (eg hydrogen) and an oxidant (eg oxygen) to continuously generate electrical energy. Because of its high efficiency and no pollution to the environment, it has become a key technology for energy substitution. Proton exchange membrane (PEM) fuel cell is a typical hydrogen-oxygen fuel cell, which can be applied to mobile power, backup power, and electric vehicles. Proton exchange membrane fuel cells have two types of systems operating at low pressure and operating at high pressure. Both low pressure and high pressure systems have their advantages.

In the fuel cell system, in addition to the fuel cell itself, other auxiliary devices are needed to ensure the reliable and continuous operation of the fuel cell system. One of the important auxiliary parts is the compressor-expander system that provides compressed air to the fuel cell. For low-pressure fuel cell systems, due to the low pressure of the air discharged from the fuel cell, only a compressor can be used; while for a high-pressure fuel cell system, since the air discharged from the fuel cell has a relatively high pressure, in order to improve the fuel cell System efficiency, expanders are often used in the system to recover energy. The pressure of the fuel cell system changes with the working conditions, but the expansion ratio of the expander is constant. When the inlet pressure of the expander is lower than the design pressure, overexpansion will occur in the expander, resulting in additional power consumption .

Contents of the invention

The purpose of the present invention is to provide a compressor-expander system suitable for both low-pressure and high-pressure fuel cell systems, which has a simple structure, and the expander can be selected according to different situations.

In order to achieve the above object, the technical solution adopted by the present invention is: comprising a motor and a first-stage compressor connected to the output shaft of the motor, the outlet of the first-stage compressor communicates with the inlet of the fuel cell stack through a pipeline, and its characteristics are: The outlet pipeline of the fuel cell stack is also connected in parallel with a solenoid valve and an expander solenoid valve. The expander communicates with the fuel cell stack through the pipeline and the expander solenoid valve. The pipeline connecting the primary compressor and the fuel cell stack is also provided with a Solenoid valve, the outlet of the primary compressor can also be connected with the inlet of the secondary compressor through the solenoid valve of the secondary compressor, the outlet of the secondary compressor is connected with the inlet of the fuel cell stack through the check valve, and the secondary compressor The machine is connected with the output shaft of the motor through the electromagnetic clutch and transmission device of the secondary compressor, and the other output shaft of the motor is connected with the expander through the expander clutch.

Another feature of the present invention is: the motor can also be directly connected with the second-stage compressor through the electromagnetic clutch of the second-stage compressor, and the other output shaft of the motor is connected with the first-stage compressor and the expander through a transmission device. An expander electromagnetic clutch is arranged between the transmission device 7; the expander includes an expansion chamber composed of a movable scroll and a fixed scroll, and an axial gas passage communicated with the expansion chamber is opened on the fixed scroll and connected with the expander. The radial gas channel connected to the air inlet of the fixed scroll is also equipped with a spring and a piston on the radial gas channel on the back of the static scroll, and a gas channel that can communicate with the axial gas channel is opened on the piston.

Because the motor of the present invention is connected with the secondary compressor and the expander through the electromagnetic clutch, and at the same time, the electromagnetic valve on the pipeline can selectively connect the primary compressor with the secondary compressor and the expander, that is, it is suitable for low-pressure It is also suitable for high-voltage fuel cell systems. For low-voltage fuel cell systems, the motor drives a first-stage compressor, and the air compressed by the first-stage compressor enters the fuel cell stack and then is discharged into the atmosphere; for high-voltage fuel cell systems, the air is compressed by the first stage. After being compressed by the compressor, it continues to enter the secondary compressor for compression, and then it is supplied to the fuel cell stack. The air discharged from the fuel cell stack enters the expander to expand and perform work, and then is discharged into the atmosphere.

Description of drawings

Fig. 1 is the overall structural representation of the present invention, wherein Fig. 1 (a) is the structural representation of embodiment 1 of the present invention, Fig. 1 (b) is the structural representation of embodiment 2 of the present invention;

Fig. 2 is a schematic structural view of the expander 12 of the present invention.

Detailed ways

The structural principle and working principle of the present invention will be further described in detail below in conjunction with the accompanying drawings.

Embodiment 1, referring to Fig. 1 (a), Fig. 2, the present invention comprises motor 1 and the primary compressor 2 that is connected with the output shaft of motor 1, the output shaft of motor 1 also passes through secondary compressor electromagnetic clutch 6 and The transmission device 7 is connected with the secondary compressor 5, and the other output shaft of the motor 1 is connected with the expander 12 through the expander clutch 13. The expander 12 includes an expansion chamber 14 composed of a movable scroll 15 and a fixed scroll 16. The fixed scroll 16 is provided with an axial gas passage 22 communicating with the expansion chamber 14 and a radial gas passage 20 communicating with the air inlet 21 of the expander 12. The back of the fixed scroll 16 is also covered with a spring 17 and Piston 18, piston 18 is in communication with radial gas channel 20, and piston 18 is also provided with the gas channel 19 that can communicate with axial gas channel 22 simultaneously, and the outlet of first-stage compressor 2 is respectively connected with solenoid valve 3, The solenoid valve 4 of the secondary compressor communicates with the inlet of the fuel cell 9 and the secondary compressor 5, the outlet of the secondary compressor 5 communicates with the inlet of the fuel cell stack 9 through the check valve 8, and the outlet of the fuel cell stack 9 A solenoid valve 10 and an expander solenoid valve 11 are also connected in parallel on the pipeline, and the expander 12 communicates with the fuel cell stack 9 through the pipeline and the expander solenoid valve 11 . In the low-pressure fuel cell system, the working process of the present invention is as follows: the motor 1 drives the primary compressor 2, the electromagnetic clutch 6 of the secondary compressor and the electromagnetic clutch 13 of the expander are disconnected, that is, the secondary compressor 5 and the expander 12 are not connected. Work. The solenoid valve 4 of the secondary compressor is disconnected, the solenoid valve 3 is connected, and the air is compressed by the primary compressor 2 and then directly enters the low-pressure fuel cell stack 9 after passing through the solenoid valve 3 . At this time, the solenoid valve 10 is turned on, and the expander solenoid valve 11 is turned off, so the air discharged from the fuel cell stack 9 passes through the solenoid valve 10 and then is discharged into the atmosphere. In the high-pressure fuel cell system, the working process of the present invention is as follows: the motor 1 directly drives the primary compressor 2, and drives the secondary compressor 5 through the transmission device 7. The electromagnetic clutch 6 of the secondary compressor and the electromagnetic clutch 13 of the expander are connected, the solenoid valve 3 and the solenoid valve 10 are disconnected, the solenoid valve 4 of the secondary compressor is connected with the solenoid valve 11 of the expander, and the air is compressed by the primary compressor 2 Then enter the secondary compressor 5 through the solenoid valve 4 of the secondary compressor, then enter the high-pressure fuel cell stack 9 through the check valve 8, and the air discharged from the fuel cell stack 9 enters the expander 12 for expansion after passing through the solenoid valve 11 of the expander Work is done and then released into the atmosphere. The work generated by the expansion is transmitted to the first-stage compressor to achieve the purpose of recovering work. The piston 18 in the expander 12 is subjected to the two-way action of the intake pressure and the force of the spring 17. When the actual intake pressure of the intake hole 21 of the expander 12 is greater than or equal to the design intake pressure of the expander 12, since the gas pressure is greater than that of the spring 17, the gas pressure pushes the piston 18 through the radial gas passage 20, so that the gas passage 19 on the piston 18 cannot communicate with the axial passage 22 on the fixed scroll 16, and the expansion process of the gas in the expander 12 continues To the designed exhaust process, when the actual intake pressure of the expander 12 is lower than the design intake pressure, the gas force acting on the piston 18 decreases, and the piston moves downward under the action of the spring 17. At this time, the static The axial channel 22 on the scroll 16 communicates with the radial gas channel 20 on the piston 18, so that the exhaust process of the expander 12 is advanced, thereby avoiding the extra power consumption caused by over-expansion.

Embodiment 2: referring to Fig. 1 (b), Fig. 2, motor 1 of the present invention is directly connected with secondary compressor 5 by secondary compressor electromagnetic clutch 6, and another output shaft of motor 1 is connected with a transmission device 7 The first-stage compressor 2 is connected to the expander 12, and an expander electromagnetic clutch 13 is arranged between the expander 12 and the transmission device 7. The other connections and working principles are the same as those in Embodiment 1.

In the present invention, through the action of the electromagnetic valve and the electromagnetic clutch in the system, for the low-voltage fuel cell system, the motor drives the first-stage compressor, and the air compressed by the first-stage compressor enters the fuel cell stack, and then is discharged into the atmosphere; for the high-voltage fuel cell system, After being compressed by the primary compressor, the air continues to enter the secondary compressor for compression, and then is supplied to the fuel cell stack. The air discharged from the fuel cell stack enters the expander to expand and perform work, and then is discharged into the atmosphere, which is suitable for both low pressure and in high-voltage fuel cell systems.

Claims (2)

1, a kind of fuel cell compressor-expander system, comprise a motor [1] and a stage compressor [2] that is connected with the output shaft of motor [1], the outlet of one stage compressor [2] is connected by the inlet of pipeline with fuel cell pack [9], it is characterized in that: also be parallel with electromagnetically operated valve [10] and decompressor electromagnetically operated valve [11] on the outlet conduit of fuel cell pack [9], decompressor [12] is connected with fuel cell pack [9] by pipeline and decompressor electromagnetically operated valve [11], also be provided with electromagnetically operated valve [3] on one stage compressor [2] and the pipeline that fuel cell pack [9] is connected, the outlet of one stage compressor [2] is connected by the inlet of split-compressor electromagnetically operated valve [4] with split-compressor [5], the outlet of split-compressor [5] is connected by the inlet of unidirectional valve [8] with fuel cell pack [9], split-compressor [5] links to each other with the output shaft of transmission device [7] with motor [1] by split-compressor electromagnetic clutch [6] again, and another output shaft of motor [1] links to each other with decompressor [12] by decompressor clutch [13].

2, fuel cell compressors-expander system according to claim 1, it is characterized in that: said decompressor [12] comprises the expansion chamber of being made up of movable orbiting scroll [15] and quiet whirlpool dish [16] [14], on quiet whirlpool dish [16], offer axial gas passage [22] that is connected with expansion chamber [14] and the radial gas passages [20] that is connected with the air inlet [21] of decompressor [12], also be set with spring [17] and piston [18] on the back side radial gas passages [20] of quiet whirlpool dish [16], also offer the gas passage [19] that can be connected on the piston [18] with axial gas passage [22].

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