A fuel cell air compressor air cooling and sealing system

Abstract

The present invention discloses an air cooling and sealing system for a fuel cell air compressor, comprising an air compressor; an airway flow structure, wherein the airway flow structure is arranged in the air compressor, and the airway flow structure comprises a main air inlet, an axial air inlet duct and a radial air inlet duct; a sealing structure, wherein the sealing structure is arranged at both axial ends of the air compressor; while satisfying a reasonable air cooling flow ratio of each part, the structure of the air cooling flow channel system is simplified, and the additional annular structure of the above-mentioned patent is avoided; in terms of sealing design, the sealing structure takes into account the balanced axial force, determines the direct size, adopts a labyrinth seal design, and optimizes the geometric size, thereby reducing leakage and improving the compression efficiency of the air compressor.

Description

Technical Field

[0001] The invention relates to the technical field of fuel cell air compressor sealing, and in particular to an air cooling and sealing system for a fuel cell air compressor. Background Art

[0002] As technology matures and costs continue to fall, fuel cell vehicles are increasingly recognized by governments and companies as the development direction of new energy vehicles, and many well-known companies have increased their investment in the research and development of fuel cell systems. As an important component, the air compressor for fuel cell vehicles provides high-pressure air for the cathode reaction of the fuel cell. Its cost and energy consumption account for about 20% of the fuel cell system, and its performance directly affects the performance of the fuel cell system.

[0003] The mainstream fuel cell air compressors currently on the market and developed by various companies all use permanent magnet synchronous motors + air foil bearings, and the air cooling system is directly used to cool the bearing system, taking away the wind loss between the rotor and the stator and the heat of the rotor. The diameter of the air cooling system is related to the reliability of the entire rotor system. At the same time, in order to ensure the efficiency of air cooling, it is necessary to effectively separate the cooling air duct and the high-pressure gas at the pressure wheel. Due to the high-speed rotation of the rotor, an efficient and reliable sealing system needs to be designed.

[0004] Garrett (formerly affiliated with Honeywell) is the earliest company to commercialize fuel cell air compressors. Regarding the cooling system and sealing system of its products, patent US_2015_0275920_A1 discloses a cooling and sealing system for a fuel cell air compressor, but its air cooling flow channel is complex, and a large number of holes need to be reserved on the shell and the back plate, which is difficult to manufacture; and the air-cooling gas of the low-pressure stage and the high-pressure stage is directly sprayed radially onto the high-speed rotor, which firstly increases the flow loss of the air-cooling gas, and secondly brings many uncertainties to the stability of the rotor, and there is a great risk of failure; the sealing mechanism of the low-pressure stage and the high-pressure stage uses sealing rings, which are relatively difficult to install, and there is a risk of friction between the sealing ring and the high-speed rotor, which brings the risk of rotor instability. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] In view of the above problems existing in the air cooling and sealing systems of the existing fuel cell air compressors, the present invention is proposed.

[0007] It is therefore an object of the present invention to provide a fuel cell air compressor air cooling and sealing system.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions: including an air compressor; an air duct circulation structure, which is arranged in the air compressor, and the air duct circulation structure includes a main air intake duct, an axial air intake duct and a radial air intake duct; a sealing structure, which is arranged at both axial ends of the air compressor.

[0009] As a preferred solution of the air cooling and sealing system of the fuel cell air compressor of the present invention, the air compressor includes a motor housing, a motor rotor system located inside the motor housing, the motor rotor system includes a low-pressure end and a high-pressure end, a back plate matching the motor housing is provided on one side of the motor housing where the low-pressure end is located, an air bearing is provided between the motor housing and the motor rotor system, the main air inlet duct is located in the radial direction inside the motor housing, and the axial air inlet duct is located in the axial direction inside the motor housing.

[0010] As a preferred solution of the fuel cell air compressor air cooling and sealing system of the present invention, the radial air intake duct includes a low-pressure end air intake duct and a high-pressure end air intake duct, wherein the low-pressure end air intake duct is located on the back plate, and the high-pressure end air intake duct is located at the high-pressure end direction of the motor housing.

[0011] As a preferred solution of the fuel cell air compressor air cooling and sealing system of the present invention, a positioning ring is arranged between the motor housing and the back plate, a plurality of cooling air ducts are arranged on the positioning ring, and a rotating part is arranged between the positioning ring and the motor rotor system.

[0012] As a preferred solution of the fuel cell air compressor air cooling and sealing system of the present invention, the cooling air duct is arranged tangentially to the motor rotor system, and the tangential direction of the cooling air duct is consistent with the rotation direction of the motor rotor system.

[0013] As a preferred solution of the fuel cell air compressor air cooling and sealing system of the present invention, wherein: the sealing structure is arranged between the motor rotor system and the back plate; a baffle is arranged between the motor housing and the motor rotor system, and the sealing structure is arranged between the baffle and the motor rotor system.

[0014] As a preferred solution of the fuel cell air compressor air cooling and sealing system of the present invention, the sealing structure includes a sealing rod and multiple groups of protrusions located on the sealing rod, wherein gaps are left between the protrusions and the back plate and the baffle, and the protrusions are arranged in at least three groups.

[0015] As a preferred solution of the fuel cell air compressor air cooling and sealing system of the present invention, wherein: the gap between the top of the protrusion and the back plate and the baffle is defined as gap K, the height of the protrusion is defined as tooth height H, the distance between two adjacent groups of the protrusions is defined as tooth pitch L, and the annular diameter of the protrusion itself is defined as diameter M.

[0016] As a preferred solution of the fuel cell air compressor air cooling and sealing system of the present invention, the gap K is 0.1mm~0.5mm, the tooth height H is 0.5mm~2mm, the tooth pitch L is 1mm~3mm, and the diameter M is 30mm~50mm.

[0017] As a preferred solution of the fuel cell air compressor air cooling and sealing system of the present invention, the gap K is 0.3 mm, the tooth height H is 1 mm, the tooth pitch L is 2.5 mm, and the diameter M is 40 mm.

[0018] The beneficial effects of the present invention are as follows: while satisfying the reasonable air-cooling flow ratio of each part, the structure of the air-cooling flow channel system is simplified, avoiding the extra annular structure of the above-mentioned patent; at the low-pressure stage, the air cooling gas is evenly distributed through the holes of the positioning ring, and the air intake of the air cooling is changed to tangential intake, and the direction is the same as the rotation direction, which improves the cooling efficiency, reduces unnecessary air flow loss, and avoids direct radial excitation of the air flow to the rotor; at the high-pressure stage, the air-cooling intake uses a stationary baffle to change the last radial intake to axial intake, and avoids direct radial excitation of the air flow to the rotor; in the sealing design, the sealing structure takes into account the balanced axial force, determines the direct size, adopts a labyrinth seal design, and optimizes the geometric size, so as to reduce the leakage and improve the compression efficiency of the air compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0020] Figure 1 It is a schematic cross-sectional view of the overall structure of the air cooling and sealing system of the fuel cell air compressor of the present invention.

[0021] Figure 2 This is a schematic diagram of the positioning ring structure of the fuel cell air compressor air cooling and sealing system of the present invention.

[0022] Figure 3 This is a schematic diagram of the sealing structure of the air cooling and sealing system of the fuel cell air compressor of the present invention.

[0023] Figure 4 It is a schematic diagram of the gas flow direction in the air cooling and sealing system of the fuel cell air compressor of the present invention.

[0024] Figure 5 This is a schematic diagram of the gas flow direction in the positioning ring of the fuel cell air compressor air cooling and sealing system of the present invention.

[0025] Figure 6 This is a schematic diagram of the streamline distribution of the sealing structure of the fuel cell air compressor air cooling and sealing system of the present invention.

[0026] Figure 7 This is a schematic diagram of the pressure distribution of the sealing structure of the fuel cell air compressor air cooling and sealing system of the present invention.

[0027] Figure 8 This is a diagram of the impeller pressure distribution of the motor rotor system of the fuel cell air compressor air cooling and sealing system of the present invention.

[0028] Fig. 9 This is a schematic diagram of the impeller pressure distribution analysis of the fuel cell air compressor air cooling and sealing system of the present invention. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0030] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0031] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0032] Secondly, the present invention is described in detail with reference to the schematic diagram. When describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0033] Example 1

[0034] Reference Figure 1 , provides a schematic diagram of the overall structure of the fuel cell air compressor air cooling and sealing system, such as Figure 1 , a fuel cell air compressor air cooling and sealing system includes an air compressor 100, an air passage flow structure 200 and a sealing structure 300;

[0035] Specifically, the main structure of the present invention includes an airway flow structure 200, which is arranged in the air compressor 100, and the airway flow structure 200 includes a main air inlet 201, an axial air inlet pipe 202 and a radial air inlet pipe 203; a sealing structure 300, and the sealing structure 300 is arranged at both axial ends of the air compressor 100.

[0036] Furthermore, the main air intake duct 201 is used to introduce external air flow into the motor housing, wherein the axial air intake duct 202 is mainly used to guide the gas to the left and right sides of the motor housing, and then the gas enters the left and right sides and then enters the radial air intake duct 203, thereby guiding the gas to the air bearing in the fuel cell air compressor. At the same time, sealing structures 300 are provided at both ends of the air compressor 100 to reduce gas leakage.

[0037] Example 2

[0038] Reference Figure 1 , 2 , 4, 5, this embodiment is different from the first embodiment in that: the air compressor 100 includes a motor housing 101, a motor rotor system 102 located inside the motor housing 101, the motor rotor system 102 includes a low-pressure end 102a and a high-pressure end 102b, a back plate 103 matching the motor housing 101 is provided on one side of the motor housing 101 where the low-pressure end 102a is located, the back plate 103 and the motor housing 101 are detachably connected, an air bearing 104 is provided between the motor housing 101 and the motor rotor system 102, the main air inlet duct 201 is located in the radial direction inside the motor housing 101, and the axial air inlet duct 202 is located in the axial direction inside the motor housing 101, and is arranged parallel to the motor rotor system 102.

[0039] Specifically, the radial air intake duct 203 includes a low-pressure air intake duct 203a and a high-pressure air intake duct 203b, wherein the low-pressure air intake duct 203a is located on the back plate 103, that is, a groove is provided on the back plate 103 to serve as the low-pressure air intake duct 203a, and the high-pressure air intake duct 203b is located in the high-pressure end direction of the motor rotor system 102, that is, on the left side of the motor housing 101, and a positioning ring 105 is installed between the motor housing 101 and the back plate 103, and a plurality of groups of windings are provided on the positioning ring 105. The cooling air duct 105a is arranged in a circular ring shape on the motor rotor, and the cooling air duct 105a is arranged tangentially along the positioning ring 105. Its function is to change the direction of the intake air, prevent the cooling gas from blowing directly to the impeller of the motor rotor, avoid direct radial excitation of the rotor by the airflow, and improve the cooling efficiency, thereby improving the performance of the air compressor. A rotating part 106 is arranged between the positioning ring 105 and the motor rotor system 102, that is, the rotating part 106 is sleeved on the rotating shaft of the motor rotor system 102.

[0040] Furthermore, a sealing structure 300 is provided between the motor rotor system 102 and the back plate 103. Similarly, on the right side of the motor housing 101, a baffle 107 is provided between the motor housing 101 and the motor rotor system 102, and a sealing structure 300 identical to that on the left side is provided between the baffle 107 and the motor rotor system 102. The function of the baffle 107 here is to change the direction of the air flow entering the high-pressure end air intake pipe 203b, so that the gas can change its path and enter the high-pressure end air bearing 104, so that the high-pressure end air bearing 104 can work. Similarly, at the low-pressure end, the direction of the gas is changed by the cooling air duct 105a on the positioning ring 105, and it is introduced into the low-pressure end air bearing 104, so that the air bearings 104 on both sides can work by relying on the gas entering from the same direction.

[0041] The specific working principle is as follows: after the gas enters the axial intake duct 202 and the radial intake duct 203 from the main intake duct 201, when the gas flows downward along the high-pressure end intake duct 203b, it will encounter the isolation of the baffle 107, causing the gas to turn and flow to the high-pressure end air bearing 104. At this time, part of the gas will flow out from the sealing structure 300, but because the impeller outside the sealing structure 300 causes the internal air pressure to be lower than the external air pressure, a part of the external gas will flow back and enter the air bearing 104 and supply it to the air bearing 104. Similarly, when entering the low-pressure side The gas at the air duct 203a will enter the positioning ring 105 and flow tangentially along the cooling air channel 105a on the positioning ring 105. On the one hand, it avoids radial excitation of the impeller, and on the other hand, it can improve the cooling efficiency. At the same time, the sealing structure 300 reduces the gas leakage in the entire motor housing 101 to a minimum, and the gas flowing out from the cooling air channel 105a enters the low-pressure air bearing 104 and is supplied to the low-pressure air bearing 104 for operation. Part of the gas flowing out from the high-pressure air bearing 104 flows out from the internal air leakage channel of the motor housing 101.

[0042] Example 3

[0043] Reference Figure 3 This embodiment is different from the above embodiments in that the sealing structure 300 includes a sealing rod 302 and a plurality of groups of annular protrusions 301 located on the sealing rod 302. A preferred solution here is that the number of groups of the annular protrusions 301 is 3.

[0044] Specifically, there is a certain gap between the protrusion 301 and the back plate 103 and the baffle 107, and this gap is defined as gap K, and the height of the protrusion 301 itself is defined as tooth height H, and the distance between two adjacent groups of protrusions 301 is defined as tooth pitch L, and the annular diameter of the annular protrusion 301 itself is defined as diameter M.

[0045] Furthermore, the size of the gap (K) is 0.1mm~0.5mm, the size of the tooth height (H) is 0.5mm~2mm, the size of the tooth pitch (L) is 1mm~3mm, and the size of the diameter (M) is 30mm~50mm. When the above four standard values ​​are within the above value range, the overall cooling efficiency and sealing degree of the fuel cell air compressor are within a better range.

[0046] Example 4

[0047] Referring to Tables 1 to 5, this embodiment is different from the above embodiments in that when the number of groups of the protrusions 301 is 4, the gap K is 0.3 mm, the tooth height H is 1 mm, the tooth pitch L is 2.5 mm, and the diameter M is 40 mm, the fuel cell air compressor has the best working efficiency and can reduce the leakage to the minimum value.

[0048] Specifically, Table 1 is the control experimental data of changing the number of protrusions 301, Table 2 is the control experimental data of changing the diameter M value based on the test results of Table 1, Table 3 is the control experimental data of changing the height of the protrusion 301 based on the test results of Tables 1 and 2, Table 4 is the control experimental data of changing the tooth pitch L value based on the test results of Tables 1, 2 and 3, and Table 5 is the control experimental data of only changing the gap K value based on the above four values.

[0049] It can be seen from the test results that when the gap K is 0.3mm, the tooth height H is 1mm, the tooth pitch L is 2.5mm, the diameter M is 40mm, and the number of protrusions 301 is 4, the sealing performance of the fuel cell air compressor is optimal.

[0050] Table 1

[0051] Number of tooth Height of tooth Distance of tooth (tooth pitch L) Clearance Radius(radius H / 2) Pressure up Pressure down Tooth type Leaked airmass flow mm mm mm mm Mpa Mpa kg / s 2 3 3 0.5 25 0.2 0.1 Tooth interlocking 0.0214 3 3 3 0.5 25 0.2 0.1 Tooth interlocking 0.0167 4 3 3 0.5 25 0.2 0.1 Tooth interlocking 0.0144

[0052] Table 2

[0053] Number of tooth Height of tooth Distance of tooth (tooth pitch L) Clearance Radius(radius H / 2) Pressure up Pressure down Tooth type Leaked airmass flow mm mm mm mm Mpa Mpa kg / s 4 3 3 0.5 25 0.2 0.1 Tooth interlocking 0.0144 4 3 3 0.5 22.5 0.2 0.1 Tooth interlocking 0.0130 4 3 3 0.5 20 0.2 0.1 Tooth interlocking 0.0117

[0054] Table 3

[0055] Number of tooth Height of tooth Distance of tooth (tooth pitch L) Clearance Radius(radius H / 2) Pressure up Pressure down Tooth type Leaked airmass flow mm mm mm mm Mpa Mpa kg / s 4 3 3 0.5 22.5 0.2 0.1 Tooth interlocking 0.0130 4 2 3 0.5 22.5 0.2 0.1 Tooth interlocking 0.0128 4 1.5 3 0.5 22.5 0.2 0.1 Tooth interlocking 0.0127 4 1 3 0.5 22.5 0.2 0.1 Tooth interlocking 0.0126

[0056] Table 4

[0057] Number of tooth Height of tooth Distance of tooth (tooth pitch L) Clearance Radius(radius H / 2) Pressure up Pressure down Tooth type Leaked airmass flow mm mm mm mm Mpa Mpa kg / s 4 2 3 0.5 22.5 0.2 0.1 Tooth interlocking 0.012805 4 2 2 0.5 22.5 0.2 0.1 Tooth interlocking 0.012809 4 2 1 0.5 22.5 0.2 0.1 Tooth interlocking 0.012819

[0058] Table 5

[0059] Number of tooth Height of tooth Distance of tooth (L) Clearance Radius(radius H / 2) Pressure up Pressure down Tooth type Leaked airmass flow (Leakage volume) mm mm mm mm Mpa Mpa kg / s 6 1 2 0.5 22.5 0.2 0.1 tooth interlocking 0.010083 6 1 2 0.4 22.5 0.2 0.1 tooth interlocking 0.008042 6 1 2 0.3 22.5 0.2 0.1 tooth interlocking 0.006010 6 1 2 0.2 22.5 0.2 0.1 tooth interlocking 0.003990

[0060] Importantly, it should be noted that the construction and arrangement of the present application shown in a number of different exemplary embodiments are only exemplary. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible (e.g., the size, scale, structure, shape and proportion of various elements, and parameter values ​​(e.g., temperature, pressure, etc.), mounting arrangements, use of materials, color, changes in orientation, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in the application. For example, an element shown as integrally formed may be composed of multiple parts or elements, the position of the element may be inverted or otherwise changed, and the nature or number or position of the discrete element may be altered or changed. Therefore, all such modifications are intended to be included within the scope of the present invention. The order or sequence of any process or method steps may be changed or reordered according to an alternative embodiment. In the claims, any "device plus function" clause is intended to cover the structure described herein that performs the function, and is not only structurally equivalent but also equivalent structure. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present invention. Therefore, the invention is not limited to a specific embodiment, but extends to numerous modifications still falling within the scope of the appended claims.

[0061] Additionally, in order to provide a concise description of exemplary embodiments, all features of an actual embodiment may not be described (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those features that are not relevant to implementing the invention).

[0062] It will be appreciated that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but will be a routine task of design, fabrication, and production for those of ordinary skill having the benefit of this disclosure without undue experimentation.

[0063] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A fuel cell air compressor air cooling and sealing system, characterized in that: include, Air compressor (100); An air passage flow structure (200), the air passage flow structure (200) being arranged in the air compressor (100), the air passage flow structure (200) comprising a main air intake duct (201), an axial air intake duct (202) and a radial air intake duct (203); A sealing structure (300), wherein the sealing structure (300) is arranged at two axial ends of the air compressor (100); The air compressor (100) comprises a motor housing (101), and a motor rotor system (102) located inside the motor housing (101); the motor rotor system (102) comprises a low-pressure end (102a) and a high-pressure end (102b); a back plate (103) matching the motor housing (101) is provided on one side of the motor housing (101) where the low-pressure end (102a) is located; an air bearing (104) is provided between the motor housing (101) and the motor rotor system (102); the main air inlet duct (201) is located in a radial direction inside the motor housing (101); and the axial air inlet duct (202) is located in an axial direction inside the motor housing (101); The radial air intake pipeline (203) comprises a low-pressure air intake pipeline (203a) and a high-pressure air intake pipeline (203b), wherein the low-pressure air intake pipeline (203a) is located on the back plate (103), and the high-pressure air intake pipeline (203b) is located in the high-pressure end direction of the motor housing (101); A positioning ring (105) is provided between the motor housing (101) and the back plate (103); a plurality of cooling air channels (105a) are provided on the positioning ring (105); and a rotating member (106) is provided between the positioning ring (105) and the motor rotor system (102); The cooling air channel (105a) is arranged tangentially to the motor rotor system (102), and the tangential direction of the cooling air channel (105a) is consistent with the rotation direction of the motor rotor system (102); The sealing structure (300) is provided between the motor rotor system (102) and the back plate (103); a baffle (107) is provided between the motor housing (101) and the motor rotor system (102); and the sealing structure (300) is provided between the baffle (107) and the motor rotor system (102); The sealing structure (300) comprises a sealing rod (302) and a plurality of groups of protrusions (301) located on the sealing rod (302), wherein gaps are left between the protrusions (301) and the back plate (103) and the baffle plate (107), and at least three groups of the protrusions (301) are provided.

2. The fuel cell air compressor air cooling and sealing system according to claim 1, characterized in that: The gap between the top of the protrusion (301) and the back plate (103) and the baffle (107) is defined as a gap (K), the height of the protrusion (301) is defined as a tooth height (H), the distance between two adjacent groups of the protrusions (301) is defined as a tooth pitch (L), and the annular diameter of the protrusion (301) itself is defined as a diameter (M).

3. The fuel cell air compressor air cooling and sealing system according to claim 2, characterized in that: The gap (K) is 0.1 mm to 0.5 mm, the tooth height (H) is 0.5 mm to 2 mm, the tooth pitch (L) is 1 mm to 3 mm, and the diameter (M) is 30 mm to 50 mm.

4. The fuel cell air compressor air cooling and sealing system according to claim 3, characterized in that: The gap (K) is 0.3 mm, the tooth height (H) is 1 mm, the tooth pitch (L) is 2.5 mm, and the diameter (M) is 40 mm.

Images