A hydrogen circulation pump and a hydrogen fuel cell system

Abstract

The present application provides a hydrogen circulation pump and a hydrogen fuel cell system, relating to the technical field of circulation pumps. The hydrogen circulation pump includes a pump housing, an impeller, a motor housing, a motor shaft, a shaft end fixing member, a sealing housing, a sealing ring and a sealing gasket. Along the direction from the front end to the rear end of the motor shaft, the outer side of the motor shaft is covered with the pump housing, the sealing housing and the motor housing which are sequentially connected. There are cavities between the pump housing, the sealing housing and the motor housing and the motor shaft; in the cavities between the pump housing and the motor shaft, a shaft end fixing member and an impeller are sequentially sleeved from the inside to the outside along the radial direction of the motor shaft. The sealing ring is arranged between the impeller and the pump housing, and the sealing gasket is arranged between the pump housing and the sealing housing. The hydrogen circulation pump can completely isolate hydrogen from the outside, and solve the problem of hydrogen leakage caused by the wear of dynamic seals due to high-speed rotation. The corresponding hydrogen fuel cell system can realize the circulation of hydrogen.

Description

Technical Field

[0001] The present invention relates to the technical field of circulation pumps, and more particularly, to a hydrogen circulation pump and a hydrogen fuel cell system. Background Art

[0002] A vehicle hydrogen fuel cell system is a process in which a certain amount of hydrogen and oxygen in the air are introduced into the fuel cell stack for an electrochemical reaction to generate electric energy. During the operation of the fuel cell, there is an obvious incomplete reaction situation, that is, a lot of hydrogen does not participate in the reaction. If the unreacted hydrogen is directly discharged into the atmosphere, it will not only cause waste of hydrogen, but also pose certain safety hazards.

[0003] Currently, the mainstream solution is to achieve the recirculation of hydrogen through a hydrogen circulation pump. The water generated inside the stack is carried out through the circulation of hydrogen. After steam-water separation, it is pressurized by a hydrogen pump and then returned to the anode of the stack for reuse.

[0004] Currently, the existing fuel cell hydrogen pressurization systems mainly use low-speed rotary positive displacement circulation pumps represented by scroll and "claw type". The positive displacement circulation pump relies on changing the volume to compress the gas for pressurization. The overall structure is relatively complex, which leads to a large overall size and weight. The operating efficiency of this structure is low, and the pump operating power consumption and noise are very large. The positive displacement type pressurizes the gas by changing the volume between two rotors. The gap between the two rotors in this structure is extremely small, and the rotors are prone to jamming problems during operation due to high and low temperature changes. The rotary positive displacement circulation pump still uses traditional lubricating oil for lubrication, and it cannot truly achieve oil-free operation, and there is a risk of polluting the system after leakage.

[0005] The centrifugal circulation pump has obvious advantages in this regard. The centrifugal circulation pump increases the kinetic energy of the gas working medium by doing work on the gas working medium through the rotation of the impeller. By increasing the rotational speed, the volume and weight of the centrifugal circulation pump can be reduced. At the same time, this centrifugal circulation pump has high efficiency and low power consumption.

[0006] However, the current application of centrifugal hydrogen pumps in fuel cell systems still has at least the following defects: poor sealing performance, which easily leads to hydrogen leakage. Summary of the Invention

[0007] One of the purposes of the present invention is to provide a hydrogen circulation pump, which can effectively solve the problem of poor sealing performance of the hydrogen circulation pump in the prior art, which easily leads to hydrogen leakage.

[0008] Another purpose of the present invention is to provide a hydrogen fuel cell system, which can achieve the recirculation of hydrogen.

[0009] The present application can be implemented as follows:

[0010] In a first aspect, the present application provides a hydrogen circulation pump, which includes a circulation pump structure, a magnetic levitation motor structure, and a sealing structure. The circulation pump structure includes a pump housing and an impeller. The magnetic levitation motor structure includes a motor housing, a motor shaft, and a shaft end fixing member. The sealing structure includes a sealing housing, a sealing ring, and a sealing gasket.

[0011] Along the direction from the front end to the rear end of the motor shaft, the outer side of the motor shaft is covered with a pump housing, a sealing housing, and a motor housing that are sequentially connected. There are cavities between the pump housing and the motor shaft, between the sealing housing and the motor shaft, and between the motor housing and the motor shaft.

[0012] In the cavity between the pump housing and the motor shaft, a shaft end fixing member and an impeller are sequentially sleeved from the inside to the outside along the radial direction of the motor shaft. The sealing ring is arranged between the impeller and the pump housing, and the sealing gasket is arranged between the pump housing and the sealing housing.

[0013] In an optional embodiment, the pump housing further has a mounting cavity, and a fixing part for fixing the housing of the impeller along the axial direction of the motor shaft is arranged in the mounting cavity.

[0014] In an optional embodiment, the sealing gasket is an O-ring.

[0015] In an optional embodiment, the material for preparing the motor shaft is a magnetic conductive material.

[0016] In an optional embodiment, the outer surface of the motor shaft is subjected to a plating treatment to prevent corrosion of the motor shaft after contact with water vapor.

[0017] In an optional embodiment, the cavity formed between the sealing housing and the motor shaft is a first bearing chamber. A front radial magnetic levitation bearing sleeved on the motor shaft is arranged in the first bearing chamber. The front radial magnetic levitation bearing abuts against the sealing housing along the radial direction of the motor shaft, and a first space near the front end of the motor shaft and a second space near the rear end of the motor shaft are also left on both sides of the front radial magnetic levitation bearing in the first bearing chamber.

[0018] In an optional embodiment, the front radial magnetic levitation bearing is a five-axis degree-of-freedom active magnetic levitation bearing.

[0019] In an optional embodiment, a first position sensor sleeved on the motor shaft is further arranged in the first bearing chamber, and the first position sensor is located in the second space.

[0020] In an optional embodiment, the magnetic levitation motor structure further includes a stator assembly, and the stator assembly is arranged in the cavity between the motor shaft and the motor housing.

[0021] In an alternative embodiment, the magnetic levitation motor structure further includes an electrical connector housing and a motor cover. The electrical connector housing covers the rear end of the motor shaft, one side of the electrical connector housing abuts against the motor housing, and the other side is sealed by connecting with the motor cover. There is also a cavity between the electrical connector housing and the motor shaft.

[0022] In an alternative embodiment, the cavity formed between the electrical connector housing and the motor shaft is a second bearing chamber. A rear radial magnetic levitation bearing sleeved on the motor shaft is provided in the second bearing chamber, and the rear radial magnetic levitation bearing abuts against the electrical connector housing along the radial direction of the motor shaft.

[0023] In an alternative embodiment, the rear radial magnetic levitation bearing is a five-axis degree-of-freedom active magnetic levitation bearing.

[0024] In an alternative embodiment, the motor shaft has a stepped front end step, an intermediate step, and a rear end step, and the front radial magnetic levitation bearing and the rear radial magnetic levitation bearing are respectively sleeved at the positions of the intermediate step and the rear end step.

[0025] In an alternative embodiment, a second position sensor sleeved on the motor shaft is further provided in the second bearing chamber, and the second position sensor is located on one side of the rear radial magnetic levitation bearing close to the end of the motor shaft.

[0026] In an alternative embodiment, a thrust disk sleeved on the motor shaft is further provided in the second bearing chamber, and the thrust disk is located on one side of the second position sensor close to the end of the motor shaft.

[0027] In an alternative embodiment, an axial magnetic levitation bearing is further provided in the second bearing chamber, and the axial magnetic levitation bearing is arranged outside the thrust disk along the radial direction of the motor shaft.

[0028] In an alternative embodiment, the axial magnetic levitation bearing is a five-axis degree-of-freedom active magnetic levitation bearing.

[0029] In an alternative embodiment, a heating sheet is further provided on the outer surface of the pump housing.

[0030] In an alternative embodiment, the heating sheet is a PTC heating sheet.

[0031] In an alternative embodiment, a low-voltage connector and a high-voltage connector are further provided on the outer surface of the electrical connector housing.

[0032] In a second aspect, the present application provides a hydrogen fuel cell system, which includes a hydrogen circulation pump according to any one of the foregoing embodiments.

[0033] The beneficial effects of the present application include:

[0034] In this application, a sealed housing is connected between the motor housing and the pump housing. At the same time, a sealing ring is provided between the pump housing and the sealed housing, and a sealing ring is provided between the impeller and the pump housing, which can completely isolate hydrogen from the outside and solve the problem of hydrogen leakage caused by wear of the dynamic seal due to high-speed rotation. Moreover, the above hydrogen circulation pump has a simple structure and a small volume. The hydrogen fuel cell system containing the above hydrogen circulation pump can realize the recirculation of hydrogen. The water generated inside the fuel cell stack is taken out through the circulation of hydrogen. After steam-water separation, it is pressurized by a hydrogen pump and then returned to the anode of the fuel cell stack for reuse. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0036] Figure 1 FIG. 9 is a schematic structural diagram of the hydrogen circulation pump provided by the embodiment of the present application from the first perspective;

[0037] Figure 2 FIG. 13 is a schematic structural diagram of the hydrogen circulation pump provided by the embodiment of the present application from the second perspective.

[0038] Reference numerals: 1 - pump housing; 2 - shaft end fixing member; 3 - fixing part; 4 - sealing ring; 5 - impeller; 6 - sealing ring; 7 - sealed housing; 8 - motor housing; 9 - front radial magnetic levitation bearing; 10 - first position sensor; 11 - motor shaft; 12 - stator assembly; 13 - rear radial magnetic levitation bearing; 14 - second position sensor; 15 - axial magnetic levitation bearing; 16 - thrust disc; 17 - motor cover; 18 - low-voltage connector; 19 - high-voltage connector; 20 - heating sheet; 21 - electrical connector housing; 31 - first space; 32 - second space; 41 - front end step; 42 - intermediate step; 43 - rear end step. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated in the drawings here can be arranged and designed in various different configurations.

[0040] Accordingly, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0041] It should be noted that like reference numerals and letters denote like items in the following drawings. Therefore, once an item is defined in one drawing, it does not require further definition and explanation in subsequent drawings.

[0042] In the description of the present invention, it should be noted that if terms such as "upper", "lower", "inner", "outer", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use. This is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0043] In addition, if terms such as "first", "second", etc. are used only for distinguishing descriptions and cannot be construed as indicating or implying relative importance.

[0044] It should be noted that the features in the embodiments of the present invention can be combined with each other without conflict.

[0045] The hydrogen circulation pump and the hydrogen fuel cell system provided in the present application will be specifically described below.

[0046] Please refer to Figure 1 and Figure 2 The present application provides a hydrogen circulation pump, which includes a circulation pump structure, a magnetic levitation motor structure, and a sealing structure. Among them, the circulation pump structure includes a pump housing 1 and an impeller 5, the magnetic levitation motor structure includes a motor housing 8, a motor shaft 11, and a shaft end fixing member 2, and the sealing structure includes a sealing housing 7, a sealing ring 4, and a sealing ring 6.

[0047] A shaft end fixing member 2 is provided at the front end of the motor shaft 11, and the shaft end fixing member 2 can be a shaft end nut or other common motor fixing components.

[0048] Along the direction from the front end to the rear end of the motor shaft 11, the outside of the motor shaft 11 is covered with a pump housing 1, a sealing housing 7, and a motor housing 8 that are sequentially connected. There are cavities between the pump housing 1 and the motor shaft 11, between the sealing housing 7 and the motor shaft 11, and between the motor housing 8 and the motor shaft 11.

[0049] In the cavity between the pump housing 1 and the motor shaft 11, a shaft end fixing member 2 and an impeller 5 are sequentially sleeved from the inside to the outside along the radial direction of the motor shaft 11.

[0050] It can also be understood that the impeller 5 and the pump casing 1 are sleeved on the outside of the shaft end fixing member 2 in sequence from the inside to the outside along the radial direction of the motor shaft 11. That is, the impeller 5 is sleeved on the outer surface of the shaft end fixing member 2, and the pump casing 1 is further sleeved on the outside of the impeller 5. Or it can be understood that the front end of the motor shaft 11 extends into the inside of the pump casing 1, and the impeller 5 is installed therein, so that the impeller 5 is clamped between the pump casing 1 and the shaft end fixing member 2, and thus the impeller 5 is pressed by the shaft end fixing member 2.

[0051] The sealing ring 4 is arranged between the impeller 5 and the pump casing 1. Specifically, the sealing ring 4 is sleeved on the outer surface of the impeller 5, and the pump casing 1 is further sleeved on the outside of the impeller 5. During the installation process of the pump casing 1, the pump casing 1 presses the sealing ring 4 downward, so that the sealing ring 4 plays a sealing role between the impeller 5 and the pump casing 1, avoiding the leakage of hydrogen. At the same time, the setting of the sealing ring 4 can also play a certain role in fixing and limiting the impeller 5, the shaft end nut and the motor shaft 11 in the radial direction, avoiding the generation of gaps between the impeller 5, the shaft end nut and the motor shaft 11 in the radial direction.

[0052] In a preferred embodiment, the sealing ring 4 can be processed into a groove form, and a throttling gap can be formed between the sealing ring 4 in this form and the pump casing 1 to achieve a throttling effect.

[0053] For reference, the pump casing 1 is also provided with an installation cavity, and a fixing part 3 for fixing the casing of the impeller 5 in the axial direction of the motor shaft 11 is arranged in the installation cavity. The fixing part 3 can be, for example, a screw.

[0054] The motor housing 8 covers the middle part of the motor shaft 11 and has a gap with the pump casing 1. For reference, the pump casing 1 is sleeved on the outside of the impeller 5 at the front end of the motor shaft 11 and extends to the middle part of the motor shaft 11. The motor housing 8 is also arranged in the middle part of the motor shaft 11. There is a gap between the extended part of the pump casing 1 and the motor housing 8, and the sealing housing 7 is arranged in the above gap. And the sealing housing 7 is connected to both the pump casing 1 and the motor housing 8.

[0055] For reference, the connection between the sealing housing 7 and the pump casing 1 is a flange connection, and the connection between the sealing housing 7 and the motor housing 8 can also be a flange connection.

[0056] The sealing ring 6 is arranged between the pump casing 1 and the sealing housing 7. The sealing ring 6 plays a sealing role between the pump casing 1 and the sealing housing 7, preventing hydrogen from leaking between the pump casing 1 and the sealing housing 7. At the same time, the setting of the sealing ring 6 can also play a certain role in fixing and limiting the pump casing 1, the sealing housing 7 and the motor shaft 11 in the radial direction, avoiding the generation of gaps between the pump casing 1, the sealing housing 7 and the motor shaft 11 in the radial direction.

[0057] In an alternative embodiment, the sealing ring 6 can be an O-ring or other forms of sealing rings 6.

[0058] In this application, the preparation material of the motor shaft 11 is a magnetically conductive material, so as to achieve the purpose of magnetic levitation.

[0059] Continuing from the above, in this application, the sealed housing 7 is connected to the motor housing 8 and the pump housing 1 to form an integral body. At the same time, a sealing ring 6 is provided between the pump housing 1 and the sealed housing 7, and a sealing ring 4 is provided between the impeller 5 and the pump housing 1. Through the setting of the above sealing structure, the traditional dynamic sealing structure is cancelled, achieving the effect of completely isolating hydrogen from the outside, and thoroughly solving the problem of hydrogen leakage caused by the wear of the dynamic seal due to high-speed rotation.

[0060] In this application, the enclosed cavity formed between the sealed housing 7 and the motor shaft 11 is the first bearing chamber. The first bearing chamber is provided with a front radial magnetic levitation bearing 9 sleeved on the motor shaft 11. And the front radial magnetic levitation bearing 9 abuts against the sealed housing 7 along the radial direction of the motor shaft 11. There are also a first space 31 near the front end of the motor shaft 11 and a second space 32 near the rear end of the motor shaft 11 on both sides of the front radial magnetic levitation bearing 9 in the first bearing chamber.

[0061] For reference, the above front radial magnetic levitation bearing 9 can be a five-axis degree-of-freedom active magnetic levitation bearing.

[0062] The first bearing chamber is also provided with a first position sensor 10 sleeved on the motor shaft 11, and the first position sensor 10 is located in the second space 32. The first position sensor 10 can be used to detect the position offset of the motor shaft 11. Specifically, it can simultaneously monitor the displacement of the motor shaft 11 in the X, Y, and Z directions.

[0063] For reference, the working principle of the first position sensor 10 can include: the inductive sensor sends an AC signal of 5 - 100KHz to the sensor probe, monitors the inductance values at different positions, and obtains the position offset. The rest of the principle can refer to the prior art and will not be elaborated here. The principle of the following second position sensor 14 also applies.

[0064] Furthermore, the magnetic levitation motor structure further includes a stator assembly 12, and the stator assembly 12 is arranged in the cavity between the motor shaft 11 and the motor housing 8. It should be noted that the stator assembly 12 can refer to the corresponding structure of the motor in the prior art and will not be elaborated here.

[0065] Furthermore, the magnetic levitation motor structure further includes an electrical connector housing 21 and a motor cover 17. The electrical connector housing 21 covers the rear end of the motor shaft 11, and one side of the electrical connector housing 21 abuts against the motor housing 8, and the other side is sealed by connecting with the motor cover 17. There is also a cavity between the electrical connector housing 21 and the motor shaft 11. In addition, the electrical connector housing 21 can also be flange-connected to the motor housing 8 and the motor cover 17.

[0066] Preferably, the first bearing chamber, the motor housing 8 and the electrical connector housing 21 are coaxially positioned front and rear by a spigot.

[0067] In the present application, the cavity formed between the electrical connector housing 21 and the motor shaft 11 is the second bearing chamber. A rear radial magnetic levitation bearing 13 sleeved on the motor shaft 11 is provided in the second bearing chamber. The rear radial magnetic levitation bearing 13 abuts against the electrical connector housing 21 along the radial direction of the motor shaft 11. The main functions of the front radial magnetic levitation bearing 9 and the rear radial magnetic levitation bearing 13 are to levitate the rotor.

[0068] For reference, the above-mentioned rear radial magnetic levitation bearing 13 can also be a five-axis degree-of-freedom active magnetic levitation bearing.

[0069] In the present application, the motor shaft 11 is a stepped motor shaft 11. Specifically, it has a front step 41, an intermediate step 42 and a rear step 43 in a stepped shape. The front radial magnetic levitation bearing 9 and the rear radial magnetic levitation bearing 13 are respectively sleeved on the left and right ends of the stepped motor shaft 11, specifically arranged at the positions of the intermediate step 42 and the rear step 43 of the stepped motor shaft 11. The shaft end fixing member 2 can be arranged on the front step 41. The first position sensor 10 is arranged between the front radial magnetic levitation bearing 9 and the front shaft shoulder of the motor shaft 11.

[0070] A motor rotor magnet is arranged between the front radial magnetic levitation bearing 9 and the rear radial magnetic levitation bearing 13. After the motor rotor assembly is installed, it is inserted into the motor cavity containing the stator assembly 12.

[0071] Furthermore, a second position sensor 14 sleeved on the motor shaft 11 is also provided in the second bearing chamber. The second position sensor 14 is located on the side of the rear radial magnetic levitation bearing 13 close to the end of the motor shaft 11.

[0072] Furthermore, a thrust disk 16 sleeved on the motor shaft 11 is also provided in the second bearing chamber. The thrust disk 16 is located on the side of the second position sensor 14 close to the end of the motor shaft 11. The above-mentioned thrust disk 16 is arranged at the rear end of the motor shaft 11.

[0073] Furthermore, an axial magnetic levitation bearing 15 is also provided in the second bearing chamber. The axial magnetic levitation bearing 15 is arranged on the outer side of the thrust disc 16 along the radial direction of the motor shaft 11 to form electromagnetic forces on both sides of the thrust disc 16 to ensure that the motor shaft 11 does not axially move. It can be understood that a second position sensor 14 is arranged between the rear radial magnetic levitation bearing 13 and the axial magnetic levitation bearing 15.

[0074] The functions of the above axial magnetic levitation bearing 15 include: controlling the axial displacement of the rotor and bearing the axial force of the rotor. For reference, the above axial magnetic levitation bearing 15 can also be a five-axis degree-of-freedom active magnetic levitation bearing.

[0075] Continuing from the above, since hydrogen has a small molecular weight, it is very difficult to compress it to the required pressure. The rotational speed must be increased to 150,000 revolutions per minute, which cannot be achieved by existing ordinary high-speed ordinary bearings. The present application can effectively avoid the above problems through the setting of magnetic levitation bearings. Moreover, since the entire system inside the hydrogen circulation pump needs to strictly achieve an oil-free condition, the entry of lubricating oil into the system will contaminate the fuel cell stack. The present application can also effectively avoid the above problems through the setting of magnetic levitation bearings.

[0076] Specifically, magnetic levitation bearing technology can solve the problem that high rotational speeds cannot be achieved by rolling, and can also overcome the problem that pneumatic bearings are worn during startup, resulting in limited startup times. At the same time, since magnetic levitation operates without contact and does not require oil lubrication, it can achieve complete oil-freeness. Such a magnetic levitation bearing can be controlled by an autonomous algorithm to automatically float the rotor before the circulation pump runs, and can achieve non-contact ultra-high-speed operation throughout the process (including the startup section). At the same time, during the operation process, when the circulation pump withstands external impacts, it can independently sense the position of the rotor and achieve active control. Therefore, the magnetic levitation technology bearing used in the present application can overcome all the technical problems of conventional high-speed circulation pumps, can use electromagnetic forces to achieve rotor suspension without contact, without friction, without lubrication, and with a long service life, and is suitable for high-speed rotor systems.

[0077] Furthermore, in the present application, a heating sheet 20, such as a PTC heating sheet, is also provided on the outer surface of the pump casing 1, so as to solve the current low-temperature ice-breaking startup problem of the hydrogen pump and enable the hydrogen pump to achieve low-temperature startup.

[0078] In addition, in the present application, the outer surface of the motor shaft 11, the internal magnets of the motor, and the rotor system can all be subjected to plating treatment to make the surfaces of the above structures compatible with hydrogen and water vapor, and prevent the above structures from rusting after contacting water vapor. It should be noted that the above plating treatment can refer to the prior art to deposit a coating that can effectively prevent the motor shaft 11 from rusting after contacting water vapor.

[0079] Continuing from the above, since the hydrogen gas carries saturated water vapor, the overall material system of the hydrogen pump needs to meet the compatibility with hydrogen and can also prevent rust. At the same time, since the water vapor will freeze at low temperature after shutdown, the problem of low-temperature startup also needs to be solved. In this application, the above problems can be effectively avoided through the setting of the PTC heating sheet combined with the plating treatment on the outer surface of the motor shaft 11.

[0080] Furthermore, a low-voltage connector 18 and a high-voltage connector 19 can also be provided on the outer surface of the electrical connector housing 21.

[0081] In addition, this application provides a hydrogen fuel cell system, which includes the above hydrogen circulation pump. The hydrogen fuel cell system containing the above hydrogen circulation pump can realize the recirculation of hydrogen. Through the circulation of hydrogen, the water generated inside the fuel cell stack is taken out. After steam-water separation, it is pressurized by the hydrogen pump and then returned to the anode of the fuel cell stack for repeated use.

[0082] It should be noted that other contents and principles regarding the hydrogen circulation pump and the hydrogen fuel cell system in this application can refer to the prior art and will not be elaborated here.

[0083] In summary, the technical solutions provided by this application have at least the following advantages:

[0084] First, by adopting the magnetic levitation bearing technology, the problem that high speeds cannot be achieved by rolling is solved, and the problem that the pneumatic bearing is worn during startup, resulting in limited startup times, can also be overcome. At the same time, since the magnetic levitation runs without contact and does not require oil lubrication, it can achieve completely oil-free. This kind of magnetic levitation bearing can be controlled by an independent algorithm, which can automatically float the rotor before the circulation pump runs, and can achieve non-contact ultra-high-speed operation throughout the whole process (including the startup section). At the same time, when the recirculation pump bears external impacts during the operation process, it can independently sense the rotor position and achieve active control. Therefore, this kind of magnetic levitation technology bearing overcomes all the technical problems of the previous high-speed circulation pump and is the optimal solution for the high-speed centrifugal hydrogen circulation pump.

[0085] Second, by adopting the integrated sealing technology of the motor and the circulation pump, the traditional dynamic sealing structure is cancelled, and the hydrogen can be completely isolated from the outside. In theory, zero leakage can be achieved, and the problem of hydrogen leakage caused by the wear of the dynamic seal due to high-speed rotation is completely solved.

[0086] Third, the surface plating technology is used to specially treat the internal magnetic steel and rotor system of the motor to achieve compatibility with hydrogen and water vapor. At the same time, the PTC heating technology is adopted to solve the problem of low-temperature ice-breaking startup of the hydrogen pump, and the hydrogen pump can achieve low-temperature startup.

[0087] That is to say, the hydrogen circulation pump provided by this application has a simple structure, can truly achieve oil-free, high-speed operation, is suitable for hydrogen compression with a small volume and a high pressure ratio, and has the advantages of no leakage, good compatibility, and achieving low-temperature startup.

[0088] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A hydrogen circulation pump, characterized in that, It includes a circulating pump structure, a magnetic levitation motor structure and a sealing structure. The circulating pump structure includes a pump housing and an impeller. The magnetic levitation motor structure includes a motor housing, a motor shaft and a shaft end fixing part. The sealing structure includes a sealing housing, a sealing ring and a sealing gasket. Along the direction from the front end to the rear end of the motor shaft, the outside of the motor shaft is covered with a pump housing, a sealing housing and a motor housing which are connected in sequence. There are cavities between the pump housing and the motor shaft, between the sealing housing and the motor shaft, and between the motor housing and the motor shaft. In the cavity between the pump housing and the motor shaft, a shaft end fixing part and an impeller are sleeved in sequence from the inside to the outside along the radial direction of the motor shaft. The sealing ring is arranged between the impeller and the pump housing, and the sealing gasket is arranged between the pump housing and the sealing housing. The material for preparing the motor shaft is a magnetic conductive material. The outer surface of the motor shaft is subjected to a plating treatment so that the outer surface of the motor shaft is compatible with hydrogen and water vapor, and a heating sheet is also provided on the outer surface of the pump housing.

2. The hydrogen circulation pump according to claim 1, wherein The pump housing also has an installation cavity, and a fixing part for fixing the housing of the impeller along the axial direction of the motor shaft is arranged in the installation cavity.

3. The hydrogen circulation pump according to claim 2, characterized in that, The sealing gasket is an O-ring.

4. The hydrogen circulation pump according to claim 1, characterized in that, The cavity formed between the sealing housing and the motor shaft is a first bearing chamber. A front radial magnetic levitation bearing sleeved on the motor shaft is arranged in the first bearing chamber. The front radial magnetic levitation bearing abuts against the sealing housing along the radial direction of the motor shaft, and a first space close to the front end of the motor shaft and a second space close to the rear end of the motor shaft are also left in the first bearing chamber on both sides of the front radial magnetic levitation bearing.

5. The hydrogen circulation pump according to claim 4, characterized in that, The front radial magnetic levitation bearing is a five-axis degree-of-freedom active magnetic levitation bearing.

6. The hydrogen circulation pump according to claim 4, characterized in that, A first position sensor sleeved on the motor shaft is also arranged in the first bearing chamber, and the first position sensor is located in the second space.

7. The hydrogen circulation pump according to claim 6, characterized in that, The magnetic levitation motor structure also includes a stator assembly, and the stator assembly is arranged in the cavity between the motor shaft and the motor housing.

8. The hydrogen circulation pump according to claim 7, characterized in that, The magnetic levitation motor structure also includes an electrical connector housing and a motor cover. The electrical connector housing covers the rear end of the motor shaft, one side of the electrical connector housing abuts against the motor housing, and the other side is sealed by connecting with the motor cover. There is also a cavity between the electrical connector housing and the motor shaft.

9. The hydrogen circulation pump according to claim 8, characterized in that, The cavity formed between the electrical connector housing and the motor shaft is a second bearing chamber. A rear radial magnetic levitation bearing sleeved on the motor shaft is arranged in the second bearing chamber. The rear radial magnetic levitation bearing abuts against the electrical connector housing along the radial direction of the motor shaft.

10. The hydrogen circulation pump according to claim 9, characterized in that, The rear radial magnetic levitation bearing is a five-axis degree-of-freedom active magnetic levitation bearing.

11. The hydrogen circulation pump according to claim 10, wherein, The motor shaft has a stepped front end step, an intermediate step and a rear end step, and the front radial magnetic levitation bearing and the rear radial magnetic levitation bearing are respectively sleeved at the positions of the intermediate step and the rear end step.

12. The hydrogen circulation pump according to claim 9, characterized in that, A second position sensor sleeved on the motor shaft is further disposed in the second bearing chamber, and the second position sensor is located on one side of the rear radial magnetic bearing close to the end of the motor shaft.

13. The hydrogen circulation pump according to claim 12, characterized in that, A thrust disk sleeved on the motor shaft is further disposed in the second bearing chamber, and the thrust disk is located on one side of the second position sensor close to the end of the motor shaft.

14. The hydrogen circulation pump according to claim 13, characterized in that, An axial magnetic bearing is further disposed in the second bearing chamber, and the axial magnetic bearing is disposed outside the thrust disk along the radial direction of the motor shaft.

15. The hydrogen circulation pump according to claim 14, wherein The axial magnetic bearing is a five-axis degree-of-freedom active magnetic bearing.

16. The hydrogen circulation pump according to claim 1, wherein The heating sheet is a PTC heating sheet.

17. The hydrogen circulation pump according to claim 8, characterized in that, A low-voltage connector and a high-voltage connector are further disposed on the outer surface of the electrical connector housing.

18. A hydrogen fuel cell system, characterized in that, Comprising the hydrogen circulation pump according to any one of claims 1-17.

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