Two-stage centrifugal co-current series fuel cell air compressor with exhaust gas recovery device

Abstract

The present invention provides a two-stage centrifugal co-directional series fuel cell air compressor with an exhaust gas recovery device, comprising an electromechanical coaxial integrated rotor assembly (3), on which an electric motor (1), a two-stage co-directional series centrifugal compressor (2) and an exhaust gas recovery centripetal turbine (4) are sequentially arranged; the gas outlet of the two-stage co-directional series centrifugal compressor (2) is used to communicate with the air side inlet of the fuel cell stack, and the gas inlet of the exhaust gas recovery centripetal turbine (4) is used to communicate with the air side outlet of the fuel cell stack. The present invention has a compact structure, a simple air flow channel structure, a stable rotor installation, a good cooling effect, and reduced power consumption.

Description

Technical Field

[0001] The invention relates to a fuel cell air compressor, in particular to a two-stage centrifugal co-directional series fuel cell air compressor with an exhaust gas recovery device. Background Art

[0002] The current centrifugal two-stage direct-drive fuel cell air compressor technology without exhaust gas recovery device places the permanent magnet motor in the middle of the rotor assembly. The two-stage centrifugal compressor impellers are set at both ends of the main shaft, and a transition pipe is used between the stages to connect the first-stage volute outlet and the second-stage impeller inlet. This not only increases the pressure loss of the air flow channel, but also increases the weight of the air compressor itself, which is contrary to the lightweight design of fuel cell vehicles.

[0003] At present, the centrifugal direct-drive fuel cell air compressor technology with exhaust gas recovery device is mainly based on single-stage centrifugal compressor, which has limited ability to adapt to the full working conditions of current fuel cells. In addition, this technology requires a high rotor operating speed, which poses a high design difficulty for the motor and bearing system, and further reduces reliability. In terms of structure, most of the solutions adopted are to set the single-stage centrifugal impeller at one end of the rotor and the turbine with exhaust gas recovery device at the other end. Generally speaking, it cannot escape the traditional design layout of suspension at both ends, or there is a structural solution in which the single-stage centrifugal compressor impeller and the centripetal turbine are set back to back on one side of the permanent magnet motor. However, it is also impossible to take into account the cooling effect of the permanent magnet motor in a compact structural layout while reducing the air temperature at the inlet of the centrifugal compressor, and the power consumption is also difficult to effectively reduce. Summary of the invention

[0004] The purpose of the present invention is to provide a two-stage centrifugal co-directional series fuel cell air compressor with an exhaust gas recovery device in response to the shortcomings of the fuel cell air compressor described in the background technology, so as to improve the overall efficiency of the fuel cell system and overcome the defects of the current centrifugal fuel cell air compressor, such as high overall power consumption, non-compact structure, low pressure ratio and inability to reduce the operating speed.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A two-stage centrifugal co-directional series-connected fuel cell air compressor with an exhaust gas recovery device, characterized in that it has an electromechanical coaxial integrated rotor assembly, on which an electric motor, a two-stage co-directional series-connected centrifugal compressor and an exhaust gas recovery centripetal turbine are arranged in sequence; the gas outlet of the two-stage co-directional series-connected centrifugal compressor is used to communicate with the air side inlet of the fuel cell stack, and the gas inlet of the exhaust gas recovery centripetal turbine is used to communicate with the air side outlet of the fuel cell stack.

[0007] The two-stage centrifugal co-directional series fuel cell air compressor with an exhaust gas recovery device, wherein one side of the electromechanical coaxial integrated rotor assembly is the motor rotor shaft, a water cooling flow channel housing is installed on the motor rotor shaft through a first air bearing, a motor stator body assembly is installed on the inner side of the water cooling flow channel housing, an air channel heat conducting ring is installed on the outer side of the water cooling flow channel housing, and the air channel heat conducting ring is installed in the compressed air intake guide housing, an inlet air flow channel is formed between the compressed air intake guide housing and the water cooling flow channel housing, and the inlet air flow channel is connected to the ambient air through the air channel heat conducting ring.

[0008] The two-stage centrifugal co-directional series fuel cell air compressor with an exhaust gas recovery device has a water cooling channel between the water cooling channel housing and the air channel heat conduction ring.

[0009] The two-stage centrifugal co-directional series fuel cell air compressor with an exhaust gas recovery device, wherein an air filter assembly is provided at the inlet end of the air channel heat conduction ring.

[0010] The two-stage centrifugal co-directional series fuel cell air compressor with an exhaust gas recovery device, wherein metal fins are also provided in the air channel heat conduction ring.

[0011] The two-stage centrifugal co-directional series fuel cell air compressor with an exhaust gas recovery device, wherein a first-stage centrifugal impeller, a sleeve and a second-stage centrifugal impeller are installed on one side of the motor rotor shaft of the electromechanical coaxial integrated rotor assembly, the two-stage co-directional series centrifugal compressor has an inlet guide housing, a first-stage guide ring, a stage partition plate and an air induction volute installed in sequence, the gap between the inlet guide housing and the water cooling flow channel housing is connected to the inlet air flow channel, the first-stage guide ring is opposite to the first-stage centrifugal impeller, the stage partition plate is opposite to the sleeve, and is installed on the air induction volute by bolts, a U-shaped airflow channel is formed between the assembly formed by the stage partition plate and the air induction volute and the first-stage guide ring, the air induction volute is opposite to the second-stage centrifugal impeller, and the air induction volute outlet it has is connected to the air side inlet of the fuel cell stack.

[0012] The two-stage centrifugal co-directional series fuel cell air compressor with an exhaust gas recovery device adopts a non-contact labyrinth tooth seal between the first-stage centrifugal impeller and the second-stage centrifugal impeller.

[0013] The two-stage centrifugal co-directional series fuel cell air compressor with an exhaust gas recovery device is provided with a balancing piston ring on one side of the second-stage centrifugal impeller on the electromechanical coaxial integrated rotor assembly, and a second-stage sealing ring is provided on one side of the air induction volute, and the second-stage sealing ring is opposite to the balancing piston ring.

[0014] The two-stage centrifugal co-directional series fuel cell air compressor with an exhaust gas recovery device, wherein the exhaust gas recovery centripetal turbine includes a pre-stage guide housing, a guide ring, a guide vane assembly and an air bearing seat, and the side of the pre-stage guide housing is provided with an air collecting port, and the air collecting port is connected with the air side outlet of the fuel cell stack, and a centripetal turbine shaft is installed on the electromechanical coaxial integrated rotor assembly, and a centripetal turbine is fixed on the centripetal turbine shaft, and there is a dynamic and static gap between the guide ring and the centripetal turbine, and the dynamic and static gap is connected with the air collecting port of the pre-stage guide housing, and the guide vane assembly is also provided on the connecting path.

[0015] The two-stage centrifugal co-directional series fuel cell air compressor with an exhaust gas recovery device, wherein the air bearing seat is installed on the centripetal turbine shaft through the second air bearing, the pre-stage guide casing is fixedly connected to the air induction volute, and radially limited by the air bearing seat.

[0016] The invention has a compact structure, a simple air flow channel structure, a stable rotor installation, a good cooling effect, and reduced power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural longitudinal section view of the present invention;

[0018] Figure 2 yes Figure 1 AA partial cross-sectional view;

[0019] Figure 3 yes Figure 1 BB partial cross-sectional view;

[0020] Explanation of the reference numerals: electric motor 1; inlet air flow channel 1a; water cooling flow channel 1b; air filter assembly 11; compressed air intake guide housing 12; water cooling flow channel housing 13; end cover assembly 14; motor stator body assembly 15; air channel heat conduction ring 16; metal fin 16a; first air bearing 17; two-stage co-directional series centrifugal compressor 2; inlet guide housing 21; first-stage guide ring 22; stage partition 23; guide vane hole 23a; bleed air volute 24; second-stage sealing ring 25; electromechanical coaxial integrated rotor assembly 3; electric motor rotor shaft 31; first-stage centrifugal impeller 32; bushing 33; second-stage centrifugal impeller 34; balancing piston ring 35; centrifugal turbine shaft 36; centrifugal turbine 37; locking nut 38; exhaust gas recovery centrifugal turbine 4; pre-stage guide housing 41; guide ring 42; guide vane grid assembly 43; sealing ring 44; air bearing seat 45; second air bearing 46. DETAILED DESCRIPTION

[0021] Some specific embodiments of the present invention will be described in detail below in an exemplary and non-restrictive manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to true scale.

[0022] In order to solve the above-mentioned problems, the present invention adopts the following technical solutions:

[0023] like Figure 1 As shown, the present invention provides a two-stage centrifugal co-directional series fuel cell air compressor with an exhaust gas recovery device, which has an electromechanical coaxial integrated rotor assembly 3, on which a motor 1, a two-stage co-directional series centrifugal compressor 2 and an exhaust gas recovery centrifugal turbine 4 are arranged from left to right in sequence, the two-stage co-directional series centrifugal compressor 2 is arranged on the right side of the motor 1, and the exhaust gas recovery centrifugal turbine 4 is arranged on the right side of the two-stage co-directional series centrifugal compressor 2, and the turbine outlet and the impeller inlet direction of the two-stage co-directional series centrifugal compressor 2 are arranged oppositely along the axial direction of the electromechanical coaxial integrated rotor assembly 3 to balance part of the axial force;

[0024] The left side of the electromechanical coaxial integrated rotor assembly 3 is the motor rotor shaft 31, and a water cooling channel housing 13 is installed on the motor rotor shaft 31 through a first air bearing 17. A motor stator body assembly 15 is installed on the inner side of the water cooling channel housing 13 in an interference fit manner. An air channel heat-conducting ring 16 is installed on the outer side of the water cooling channel housing 13, and a water cooling channel 1b is left between the water cooling channel housing 13 and the air channel heat-conducting ring 16. The air channel heat-conducting ring 16 is installed in the compressed air intake guide housing 12, and an inlet air channel 1a is formed between the compressed air intake guide housing 12 and the water cooling channel housing 13. The inlet end of the air channel heat-conducting ring 16 is provided with an air filter assembly 11, and the outlet end is connected to the inlet air channel 1a; a metal fin 16a is also provided in the air channel heat-conducting ring 16, as shown in FIG. Figure 2 As shown, it is beneficial to heat exchange between the inlet gas and the water cooling channel 1b, and the number of metal fins 16a can be designed according to the situation; the outer end of the water cooling channel housing 13 is fixed by the end cover assembly 14 through bolts;

[0025] A first-stage centrifugal impeller 32, a sleeve 33, a second-stage centrifugal impeller 34 and a balancing piston ring 35 are installed from left to right on the right side of the motor rotor shaft 31 of the electromechanical coaxial integrated rotor assembly 3. The two-stage co-directional series centrifugal compressor 2 has an inlet guide housing 21, a first-stage guide ring 22, a stage partition plate 23, an air bleed volute 24 and a second-stage sealing ring 25 installed in sequence from left to right. The gap between the inlet guide housing 21 and the water cooling channel housing 13 is connected to the inlet air channel 1a. The first-stage guide ring 22 is opposite to the first-stage centrifugal impeller 32, which is fixed to the inner cavity of the inlet guide housing 21 and is assembled and fixed to the inlet guide housing 21 and the air bleed volute 24. The remaining processing error can be met through the assembly process; the stage partition plate 23 is fixed to the air bleed volute 24 by bolts, and the stage partition plate 23 and the air bleed volute are fixed to the air bleed volute 24. A certain number of airflow guide blades 23a are designed between 24, and the number of blades is set according to the situation. Bolt through holes are set in the guide blades 23a, and the stage partition plate 23 and the air induction volute 24 are fixedly installed together by bolts. The formed assembly is opposite to the shaft sleeve 33, and the processing tolerance of the U-shaped airflow channel formed with the first-stage guide ring 22 can be met through combined processing; the air induction volute 24 is opposite to the second-stage centrifugal impeller 34, and is fixedly connected to the inlet guide housing 21 by bolts; the second-stage sealing ring 25 is fixed to the right side of the air induction volute 24 and is opposite to the balance piston ring 35, and the balance piston ring 35 can balance part of the axial force; wherein, a non-contact labyrinth tooth seal is adopted between the first-stage centrifugal impeller 32 and the second-stage centrifugal impeller 34, and the outer ring of the balance piston ring 35 is provided with a non-contact labyrinth tooth seal structure; Figure 3 As shown, the air volute outlet 2a of the air volute 24 is connected to the air side inlet of the fuel cell stack through a pipeline to form an air pressurized air flow channel;

[0026] The exhaust gas recovery centrifugal turbine 4 includes a pre-stage guide casing 41, a guide ring 42, a guide vane assembly 43, a sealing ring 44 and an air bearing seat 45. A centrifugal turbine shaft 36 is installed on the right side of the balance piston ring 35 on the electromechanical coaxial integrated rotor assembly 3 by transition fit to improve the bending stiffness of the overall shaft system. The air bearing seat 45 is installed on the centrifugal turbine shaft 36 through a second air bearing 46. An air collecting port 4a is provided on the side of the pre-stage guide casing 41. The air collecting port 4a is connected to the air side outlet of the fuel cell stack through a pipeline to recycle the airflow. The pre-stage guide casing 41 is connected to the air induction volute 24 and the second stage sealing The sealing ring 25 is installed and fixed by bolts, and is radially limited by the air bearing seat 45. The sealing ring 44 is arranged on the right side of the air bearing seat 45. It should be noted that the right side surface of the air bearing seat 45 and the left side surface of the sealing ring 44 form a thrust air bearing limiting surface; the guide ring 42 is arranged on the right side of the pre-stage guide housing 41, and a centripetal turbine 37 is also fixed on the centripetal turbine shaft 36 and axially fixed with a locking nut 38. There is a dynamic and static gap between the installed guide ring 42 and the centripetal turbine 37, and there is no interference during operation. The dynamic and static gap is connected with the air collecting port 4a of the pre-stage guide housing 41, and the guide vane assembly 43 is also provided on the connecting path.

[0027] The electromechanical coaxial integrated rotor assembly 3 is supported by the first air bearing 17 and the second air bearing 46, which can improve the balance stability. The balance piston ring 35 can balance part of the pneumatic axial force, reduce the difficulty of thrust bearing design of the second air bearing 46, and improve the operation stability of the shaft system.

[0028] The present invention mainly drives the electromechanical coaxial integrated rotor assembly 3 to operate by the tangential torque generated by the magnetic field of the winding magnetic lines of force through the driver control, and then the rotor-main shaft drives the two-stage coinciding series centrifugal compressors 2 to rotate at high speed together. The different speed control of the electromechanical coaxial integrated rotor assembly 3 realizes the high-speed rotation of the two-stage coinciding series centrifugal compressors 2 to compress the air, so as to achieve a high pressure ratio and a large flow gas load output. The output gas is connected to the air side inlet of the fuel cell stack through a pipeline from the air inlet volute outlet 2a. At the same time, the high-pressure exhaust gas generated by the fuel cell stack is introduced into the air collecting port 4a of the pre-stage guide casing 41 through the pipeline. The airflow converts the high-pressure exhaust gas into kinetic energy through the guide vane assembly 43, and drives the centripetal turbine 37 to rotate at high speed together with the electromechanical coaxial integrated rotor assembly 3. The exhaust gas flow entering the pre-stage guide casing 41 is adjusted by the control logic, the output power of the motor is adaptively reduced, the speed of the electromechanical coaxial integrated rotor assembly 3 is stabilized, and the output air compressor flow and pressure ratio are stabilized. According to different input conditions, it can meet the air flow supply demand in a wide range of high-power automotive fuel cell engines.

[0029] The two-stage co-directional series centrifugal compressor 2 of the present invention has an inlet air flow channel 1a, which is connected to the air channel heat-conducting ring 16. The air channel heat-conducting ring 16 is adjacent to the water cooling channel shell 13 to form heat conduction contact. The ambient air is filtered and purified by the air filter 11, enters the air channel heat-conducting ring 16 and effectively exchanges heat with the water cooling channel shell 13, which can effectively reduce the intake temperature at the inlet of the first-stage centrifugal impeller 32, reduce the inlet gas specific volume, and improve the surge margin of the compressor.

[0030] In the present invention, the air bearing may be selected from but not limited to conventional foil type, static pressure type, static and dynamic pressure type and the like.

[0031] In the present invention, vent holes are provided on the axial right end surface of the water cooling channel housing 13 and the axial right end surface of the end cover assembly 14. The number of vent holes is set according to the situation so that the air flow can flow through the gap between the first air bearing 17 and the stator and rotor of the permanent magnet motor, thereby reducing the operating temperature of the rotor and the bearing and improving the operating reliability of the motor and the system.

[0032] In the present invention, an air filter is provided on the left end face of the compressed air intake guide housing 12 to purify the quality of the inlet air, improve the operating reliability of the air bearing, and prevent it from getting stuck during operation; and an air filter is also provided in the inner hole of the motor end cover assembly 14.

[0033] In the present invention, Figure 2 As shown, cooling ventilation holes 1c are axially arranged at the joint between the motor stator body assembly 15 and the water cooling channel housing 13. The number of cooling ventilation holes 1c is set according to the situation, which can effectively improve the heat dissipation efficiency and operation stability of the motor.

[0034] The above description is only illustrative rather than restrictive of the present invention. Those skilled in the art will understand that many modifications, changes or equivalents may be made without departing from the spirit and scope defined by the claims, but all will fall within the scope of protection of the present invention.

Claims

1. A two-stage centrifugal co-directional series fuel cell air compressor with an exhaust gas recovery device, characterized in that: The invention comprises an electromechanical coaxial integrated rotor assembly (3), on which an electric motor (1), a two-stage co-directional series-connected centrifugal compressor (2) and an exhaust gas recovery centripetal turbine (4) are sequentially arranged; the gas outlet of the two-stage co-directional series-connected centrifugal compressor (2) is used to communicate with the air side inlet of a fuel cell stack, and the gas inlet of the exhaust gas recovery centripetal turbine (4) is used to communicate with the air side outlet of the fuel cell stack; One side of the electromechanical coaxial integrated rotor assembly (3) is a motor rotor shaft (31), a water cooling channel housing (13) is mounted on the motor rotor shaft (31) via a first air bearing (17), a motor stator body assembly (15) is mounted inside the water cooling channel housing (13), an air channel heat conducting ring (16) is mounted on the outside of the water cooling channel housing (13), the air channel heat conducting ring (16) is mounted in a compressed air intake guide housing (12), an inlet air channel (1a) is formed between the compressed air intake guide housing (12) and the water cooling channel housing (13), and the inlet air channel (1a) is connected to ambient air via the air channel heat conducting ring (16); A first-stage centrifugal impeller (32), a shaft sleeve (33) and a second-stage centrifugal impeller (34) are installed on one side of the motor rotor shaft (31) of the electromechanical coaxial integrated rotor assembly (3); the two-stage co-directional series centrifugal compressor (2) comprises an inlet guide housing (21), a first-stage guide ring (22), a stage partition plate (23) and an air volute (24) which are installed in sequence; a gap between the inlet guide housing (21) and the water cooling flow channel housing (13) is connected to the inlet air flow channel (1a); The first-stage guide ring (22) is opposite to the first-stage centrifugal impeller (32), the stage partition plate (23) is opposite to the shaft sleeve (33), and is installed on the air induction volute (24) by bolts, and a U-shaped air flow channel is formed between the assembly formed by the stage partition plate (23) and the air induction volute (24) and the first-stage guide ring (22), the air induction volute (24) is opposite to the second-stage centrifugal impeller (34), and the air induction volute outlet (2a) thereof is connected to the air side inlet of the fuel cell stack; A water cooling channel (1b) is left between the water cooling channel housing (13) and the air channel heat conducting ring (16).

2. The two-stage centrifugal co-directional series fuel cell air compressor with an exhaust gas recovery device according to claim 1 is characterized in that: An air filter assembly (11) is provided at the inlet end of the air channel heat-conducting ring (16).

3. The two-stage centrifugal co-directional series fuel cell air compressor with an exhaust gas recovery device according to claim 1 is characterized in that: Metal fins (16a) are also provided in the air channel heat-conducting ring (16).

4. The two-stage centrifugal co-directional series fuel cell air compressor with an exhaust gas recovery device according to claim 1, characterized in that: A non-contact labyrinth tooth seal is used between the first-stage centrifugal impeller (32) and the second-stage centrifugal impeller (34).

5. The two-stage centrifugal co-directional series fuel cell air compressor with an exhaust gas recovery device according to claim 1, characterized in that: A balancing piston ring (35) is provided on one side of the second-stage centrifugal impeller (34) on the electromechanical coaxial integrated rotor assembly (3), and a second-stage sealing ring (25) is provided on one side of the air induction volute (24), wherein the second-stage sealing ring (25) is located opposite to the balancing piston ring (35).

6. The two-stage centrifugal co-directional series fuel cell air compressor with an exhaust gas recovery device according to claim 1, characterized in that: The exhaust gas recovery centrifugal turbine (4) comprises a pre-stage flow guide housing (41), a flow guide ring (42), a guide vane grid assembly (43) and an air bearing seat (45); a gas collecting port (4a) is provided on the side of the pre-stage flow guide housing (41); the gas collecting port (4a) is connected to the air side outlet of the fuel cell stack; a centrifugal turbine shaft (36) is installed on the electromechanical coaxial integrated rotor assembly (3); a centrifugal turbine (37) is fixed on the centrifugal turbine shaft (36); a dynamic and static gap exists between the flow guide ring (42) and the centrifugal turbine (37); the dynamic and static gap is connected to the gas collecting port (4a) of the pre-stage flow guide housing (41); and the guide vane grid assembly (43) is also provided on the connecting path.

7. The two-stage centrifugal co-directional series fuel cell air compressor with an exhaust gas recovery device according to claim 6, characterized in that: The air bearing seat 45 is mounted on the centripetal turbine shaft (36) via a second air bearing (46); the pre-stage guide casing (41) is fixedly connected to the bleed air volute (24) and radially limited via the air bearing seat (45).

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