CN213184367U

CN213184367U - Water separator for fuel cell system and fuel cell system

Info

Publication number: CN213184367U
Application number: CN202022398501.3U
Authority: CN
Inventors: 赵后辽; 赵猛; 刘杨; 沈华梁; 吴宏斐
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2020-10-26
Filing date: 2020-10-26
Publication date: 2021-05-11
Anticipated expiration: 2030-10-26

Abstract

The present application relates to a water separator for a fuel cell system and a fuel cell system, the water separator including: the water separator comprises a shell, a separation component and a water drainage component, wherein the separation component is accommodated in the shell, the water drainage component is positioned below the separation component, the shell is provided with an inlet for mixed gas containing water to enter, an outlet for separated gas to be discharged and a water drainage outlet for separated water to be discharged, the water drainage component comprises a water collector integrating separation and collection functions, the separation component comprises separation devices for separating the mixed gas for three times respectively, and the water collector comprises a separation part for separating the mixed gas and a collection part for collecting the separated water. Adopt the water separator of this application for whole size reduces, and equipment structure is compact, and separation efficiency obtains improving, can also prevent to freeze in each parts department of water separator simultaneously.

Description

Water separator for fuel cell system and fuel cell system

Technical Field

The present application relates to a proton exchange membrane fuel cell system, and more particularly, to a water separator for a proton exchange membrane fuel cell.

Background

With the popularization of electric vehicles today, pem fuel cells are widely used, in which water vapor is generated along with the operation of the fuel cell, and a part of the generated water vapor is carried out of the fuel cell stack by the air flow, a part of the generated water vapor is discharged from the cathode, and a part of the generated water vapor enters the anode cycle. After the mixed gas is discharged out of the galvanic pile, the mixed gas is condensed due to temperature reduction, and therefore, a large amount of liquid water is generated in the anode circulating gas. If the mixed gas is not subjected to water-gas separation to discharge liquid water, a lot of liquid water enters the galvanic pile along with the mixed gas, and the anode is flooded. In addition, water accumulated in the anode cycle may also increase the workload of the hydrogen circulation pump, reduce its performance, and even cause a malfunction. Therefore, it is generally necessary to provide a water separator at the anode of the fuel cell system.

However, existing water separators are all designed to have a large volume, a high pressure drop, and low separation efficiency. These large size water separators make the overall fuel cell take up too much space and are not easy to install, and also result in a reduction in the volumetric power density of the overall fuel cell system, too much pressure drop also results in excessive energy loss in the fuel cell system, and too low separation efficiency results in the entry of unseparated water into the fuel cell stack, thereby rendering the fuel cell ineffective.

Further, in the conventional water separator, in order to separate gas and water at the anode outlet, a drain assembly is included in the vortex separation device, but such a drain assembly does not precisely adjust the drain flow rate, and also does not have a heating and defrosting function, so that the accumulation of water in the water separator in a low-temperature environment causes the freezing of ice on the seating surface of the drain valve.

Accordingly, there is a need for a high efficiency water separator that can precisely control the flow rate of the water discharge and that can be reduced in size without causing icing on the surface of the water discharge member.

SUMMERY OF THE UTILITY MODEL

It is an object of the present invention to overcome the above-mentioned drawbacks of the water separators in the prior art, and to provide a water separator for a fuel cell system, which can reduce the volume of the water separator, and at the same time, can precisely control the flow rate of discharged water, and has high separation efficiency.

To this end, the present application provides a water separator for a fuel cell system, comprising: the water separator comprises a shell, a separation component and a water drainage component, wherein the separation component is accommodated in the shell, the water drainage component is positioned below the separation component, the shell is provided with an inlet for mixed gas containing water to enter, an outlet for separated gas to be discharged and a water drainage outlet for separated water to be discharged, the water drainage component comprises a water collector integrating separation and collection functions, the separation component comprises separation devices for separating the mixed gas for three times respectively, and the water collector comprises a separation part for separating the mixed gas and a collection part for collecting the separated water.

Optionally, the water separator further comprises a heating unit disposed at an outer periphery of the sump.

Optionally, the water separator further comprises a drain valve disposed between the water collector and the drain port, one end of the drain valve is connected to the drain channel of the water collector, and the other end of the drain valve is connected to the drain port of the housing.

Alternatively, the drain valve is a solenoid-operated valve that is periodically opened or closed to quantitatively discharge water.

Alternatively, the water collector has a cylindrical shape having a central cavity including a separation-collection chamber having a tapered inner surface to centrifugally separate the mixed gas and a drain passage connected to the separation-collection chamber to collect and drain the separated water.

Optionally, the separation assembly includes a cylindrical center post, an upper plate and a lower plate connected to two ends of the center post, and an impeller member disposed outside the center post and located between the upper plate and the lower plate, the impeller member including a plurality of blades extending from the center post and a fixed cylinder plate extending coaxially with a surface of the center post and connecting the blades.

Optionally, the upper surface of the lower plate is an inclined surface inclined toward the housing, and the outer diameter of the lower plate is smaller than the outer diameter of the blade.

Optionally, the upper plate is fixed directly to an inner wall of the separator housing to fix the separation assembly relative to the housing, or the upper plate is fixed to the inner wall by a fixing element.

Optionally, the vanes are inclined or curved relative to the axial direction of the impeller member.

The present application also provides a fuel cell system comprising a water separator as described above.

By adopting the water separator disclosed by the invention, the drainage flow rate can be accurately controlled, the volume of the separator is reduced, the icing on the surface of a drainage component is avoided, the separation efficiency is high, and the safe and effective use of the whole fuel cell is ensured.

Drawings

The foregoing and other aspects of the present application will be more fully understood from the following detailed description, taken together with the following drawings. It is noted that the drawings may not be to scale for clarity of illustration and will not detract from the understanding of the present application. In the drawings:

fig. 1 is a schematic cross-sectional view of a water separator for a fuel cell system according to the present application.

FIG. 2 is a perspective schematic view of a separation assembly in the water separator of FIG. 1.

FIG. 3 is a schematic cross-sectional view of the separation assembly shown in FIG. 2.

Fig. 4 is a bottom view of the decoupling assembly of fig. 2.

Fig. 5 is a side view of the separator assembly of fig. 2.

Fig. 6 is a schematic diagram of a water separator for a fuel cell system according to another embodiment of the present application.

Detailed Description

In the various figures of the present application, features that are structurally identical or functionally similar are denoted by the same reference numerals.

As shown in fig. 1, a water separator for a fuel cell system according to the present application includes a case 1, a separation module 2 accommodated in the case 1, and a drain module 3 located below the separation module 2.

The housing 1 is cylindrical, and has an inlet 4 for the mixed gas to enter and an outlet 5 for the separated mixed gas to exit at the upper part of the side wall thereof, and the housing 1 has a drain port 6 for the separated water to exit at the bottom wall thereof.

The drain opening 6 may be provided at the bottom of the housing 1 or at a lower portion of the sidewall of the housing 1, depending on the need and the specific installation environment.

Fig. 2 shows in particular in perspective view the separating assembly 2 of the water separator shown in fig. 1, fig. 3 is a schematic cross-sectional view of the separating assembly 2, the separating assembly 2 being a scroll-type separating assembly, the separating assembly 2 comprising a central column 7 having a cylindrical shape and an internal passage, and an upper plate 8 and a lower plate 9 extending from or connected to the upper and lower ends of the central column 7, respectively, the upper plate 8 being fixed to the inner wall of the housing 1 at a level between the inlet 4 and the outlet 5, optionally the upper plate 8 being interference-fitted to the inner wall of the housing 1 or otherwise connected to the inner wall of the housing 1. As can be seen from fig. 3, wherein the lower plate 9 has a smaller outer diameter than the upper plate 8, and the upper surface 10 of the lower plate 9 is an inclined surface, the upper surface 10 is configured to be inclined downward as it goes away from the center post 1, so that the water-gas mixture can flow outwardly and downwardly along the upper surface 10 of the lower plate 9.

Between the upper plate 8 and the lower plate 9, an impeller member 11 is further provided around the center post 7, the impeller member 11 being arranged closer to the lower plate 9 in the axial direction. The impeller member 11 includes a plurality of blades 12 extending outward from an outer surface of the center post 7, and a fixed cylinder plate 13 extending coaxially with the center post 7 and connecting tail ends of the plurality of blades 12, and the fixed cylinder plate 13 is cylindrical. In one embodiment, the length of the fixed cylinder 13 in the axial direction is greater than the length of the blades 12 in the axial direction, so that all the blades 12 are located entirely within the extension of the fixed cylinder 13 in the axial direction, as shown in fig. 3, in which case it may be provided that the lower surface 14 of the lower plate 9 is flush with the lower end 15 of the fixed cylinder 13, i.e. at the same height, or the lower plate 9 may be displaced slightly upwards from the height of the lower end 15, so that the lower plate 9 inside the fixed cylinder 13 is not visible from the outside of the impeller member 11, as shown in fig. 5. In another embodiment, the lower plate 9 may also be provided so as to be located axially further downward than the lower end 15 of the fixed cylinder plate 13, so as to be axially outside the fixed cylinder plate 13. In each case, the outer diameter of the lower plate 9 is preferably set smaller than the inner diameter of the fixed cylinder plate 13, as can also be clearly seen in the bottom view of the separating assembly 2 shown in fig. 4.

In the present application, the outer diameter of the fixed barrel plate 13 is set slightly smaller than the inner diameter of the housing 1 to form a clearance fit therebetween, as shown in fig. 1.

The vanes 12 are arranged uniformly along the circumference of the center post 7 and may be inclined or curved with respect to the axial direction of the center post 7, as shown in fig. 2, and the shape and arrangement of the vanes 12 may also take other inclined or curved shapes known in the impeller art.

The outer diameter of the lower plate 9 may be set smaller than the outer diameter of the blades 12.

The center post 7, the upper plate 8, and the lower plate 9 may be integrally formed of a single material, or they may be formed as a single piece and then joined together by mechanical connection.

The impeller member 11 may be integrally formed with the center post 7 from a single material, or the vanes 12 and the fixed cylindrical plate 13 may be formed as separate members and then connected to the center post 7.

Alternatively, the entire separation assembly 2 may be integrally formed of a single material by molding.

As shown in fig. 1, a drain assembly 3 is disposed inside the housing 1 below the separation assembly 2, the drain assembly 3 mainly including a water collector 16, the water collector 16 being cylindrical with a central cavity including a separation-collection chamber 17 having a tapered shape and a drain passage 18 located at the bottom of the water collector 16 and communicating with the separation-collection chamber 17. The inner surface 19 of the separation-collection chamber 17 is a conical surface whose diameter gradually decreases as it extends towards the bottom of the water collector 16 until it meets the drainage channel 18. The drain passage 18 communicates with the drain opening 6, and water separated from the mixed gas is collected in the drain passage 18 and finally discharged out of the water separator through the drain opening 6. A sealing member 20 is provided between the sump 16 and the inner wall of the housing 1 to prevent the mixed gas and water from leaking out between the sump 16 and the housing 1.

The seal 20 may be an O-ring rubber, or other seal known in the art.

Fig. 6 shows another alternative embodiment of a water separator for a fuel cell system according to the present application, in which a heating element 21 is provided at the outer periphery of the water collector 16 for heating the area near the water collector 16 and the drain passage 18 to prevent ice formation at these locations in a low-temperature environment. The heating element 21 may be an electrical heating element, or other forms of heating elements known in the art.

In the embodiment shown in fig. 6, a drain valve 22 is further provided between the sump 16 and the drain opening 6 of the housing 1, the drain valve 22 is connected at one end to the drain passage 18 and at the other end to the drain opening 6, and the on-off control of the drain valve 22 is in the form of a PWM valve, which allows the separated water stored in the separation-collection chamber 17 and the drain passage 18 to be regularly and quantitatively drained out of the water separator, i.e., the drain valve 22 is provided such that the drainage of the water can be performed in a controlled manner.

The operation of the mixed gas in the water separator according to the present application is described in detail below with reference to fig. 1 and 6.

As shown in fig. 1 and 6, the unseparated mixed gas enters the interior of the separator from the inlet 4 of the housing 1, and first flows in a rotating manner around the center post 7, so that water is separated from the mixture, i.e., centrifuged (first separation), due to the difference in centrifugal force caused by the difference in density of the media in the mixed gas;

then, the mixed gas which is not separated travels downwards, on one hand, the mixed gas collides with the blades 12 of the impeller part 11, and due to the fact that the blades are in a three-dimensional bent shape, the medium in the mixed gas is subjected to baffle separation at the blades 12 through the difference of the collision speed of the blades 12, and on the other hand, the medium collides with the fixed cylinder plate 13 of the impeller part 11, and the baffle separation (secondary separation) occurs;

the unseparated mixed gas continues to travel downward and hits the lower plate 9, the lower plate 9 guides the separated water into the inner wall of the housing 1 of the water separator, so that the gas pushes the water flow along the inner wall, and in addition, the mixed gas flowing down from the inner passages between the blades 12 of the impeller member 11 undergoes baffle separation (third separation) on the upper surface 10 of the lower plate 9, and since the upper surface 10 is an inclined surface, a part of the separated water can also drip down along the upper surface 10 of the lower plate 9 into the underlying water collector 16;

the unseparated mixed gas travels further downwards into the conical separation-collection chamber 17 of the water collector 16, hits the conical inner surface 19, the mixed gas rotates along the conical inner surface 19 of the water collector 16, its velocity differs due to the different densities of the different media, so that water is centrifugally separated from the mixture (fourth separation), and the separated water is collected in the separation-collection chamber 17 and the drainage channel 18 and subsequently discharged out of the water separator through the drainage opening 6 or, alternatively, by being discharged out of the water separator under the control of the drainage valve 22. The separated gas travels upwardly and through an internal passage in the central column 7 and out into the outlet 5 of the outer shell 1 for further use.

Thus, in the present application, the mixed gas mixed with moisture is subjected to four separations, i.e., the first separation around the center post 7, the second separation striking the impeller member 11, the third separation striking the lower plate 9, and the fourth separation striking the tapered inner surface 19, so that the separation efficiency is greatly improved.

In addition, in the present application, on the one hand, three separation elements are integrated together by the design of the integrated vortex type separation assembly 2, so that the mixed gas is separated for three times in a short time, and on the other hand, the water collector 16 in the drainage assembly 3 is designed to integrate the separation function and the water collection function, so that the overall size of the whole separator is reduced, the structure is compact, and the pressure drop can be reduced while the separation efficiency is improved.

Moreover, in the impeller member 11, the vanes 12 are connected by two cylindrical surfaces with the vanes 12 uniformly arranged therebetween, so that the overall strength of the impeller member 11 is increased while the water separator volume is reduced, while the separation efficiency can meet the requirements of the fuel cell stack.

By arranging the water discharge valve 22 in the form of a PWM valve between the water collector 16 and the water discharge opening 6, regular and quantitative control of the discharge of water is also achieved in the present application, i.e. controlled discharge of separated water and precise control of the flow rate of water.

Also in this application, the provision of the heating unit 21 around the water collector 16 and the drain passage 18 allows the drain valve 22 to be subjected to a de-icing operation before it begins to operate, while also allowing the water vapor to be less likely to freeze around the water collector and drain member in a low temperature environment, thereby negatively affecting the operation of the water separator. The heating unit 21 may be tightly wrapped around the sump 16 to improve heating efficiency.

Although specific embodiments of the present application have been described herein in detail, they have been presented for purposes of illustration only and are not to be construed as limiting the scope of the application. Various substitutions, alterations, and modifications may be conceived without departing from the spirit and scope of the present application.

Claims

1. A water separator for a fuel cell system, comprising: a housing, a separator assembly housed in the housing, and a drain assembly located below the separator assembly,

wherein the housing has an inlet for the entry of a mixed gas containing moisture and an outlet for the exit of the separated gas, and a drain outlet for the exit of the separated water, the drain assembly includes a water collector integrating the separating and collecting functions, and

wherein the separation assembly includes separation devices that respectively perform three times of separation on the mixed gas, and the water collector includes a separation portion that performs separation on the mixed gas and a collection portion that collects separated water.

2. The water separator of claim 1, further comprising a heating unit disposed at an outer periphery of the sump.

3. The water separator of claim 1 further comprising a drain valve disposed between the sump and the drain opening, the drain valve having one end connected to the drain passage of the sump and another end connected to the drain opening of the housing.

4. A water separator according to claim 3, wherein the drain valve is a solenoid-operated valve that is periodically opened or closed to provide a metered discharge of water.

5. The water separator of claim 1, wherein the water collector is in the shape of a cylinder having a central cavity including a separation-collection chamber having a tapered inner surface to centrifugally separate the mixed gas and a drain passage connected to the separation-collection chamber to collect and drain separated water.

6. The water separator of any one of claims 1-5, wherein the separation assembly comprises a cylindrical center post and upper and lower plates connected to both ends of the center post, and an impeller member disposed outside the center post and between the upper and lower plates, the impeller member comprising a plurality of vanes extending from the center post and a stationary cylindrical plate extending coaxially with the surface of the center post and connecting the vanes.

7. The water separator of claim 6, wherein the upper surface of the lower plate is an inclined surface inclined toward the housing, and an outer diameter of the lower plate is smaller than an outer diameter of the vane.

8. The water separator of claim 6 wherein the upper plate is secured directly to an inner wall of the separator housing to secure the separation assembly relative to the housing, or the upper plate is secured to the inner wall by a securing element.

9. A water separator according to claim 6, wherein the vanes are inclined or curved with respect to the axial direction of the impeller member.

10. A fuel cell system, characterized by comprising a water separator according to any one of claims 1-9.