Fuel cell membrane humidifier and fuel cell device

Abstract

The present invention discloses a fuel cell membrane humidifier and a fuel cell device, including an air inlet, a humidifying part and an air outlet that are connected in sequence; wherein the humidifying part forms a gas passage to be humidified and a wet hot water vapor passage from the inside to the outside, and the wet hot water vapor passage includes a steam inlet passage and a steam outlet passage connected to the outside; the gas passage to be humidified includes a plurality of fiber membrane tubes extending from the air inlet to the air outlet, and the diameter of the fiber membrane tube located on the outside is greater than the diameter of the fiber membrane tube located on the inside. Through the above design, the technical problem that the membrane humidifier of the fuel cell in the prior art humidifies the air unevenly, causing a large difference in the humidity of the humidified gas supplied to the inside of the fuel cell stack, which in turn has a significant impact on the humidification effect, thereby greatly affecting the service life and performance of the entire fuel cell device is solved.

Description

Technical Field

[0001] The present invention relates to the field of fuel cell structures, and in particular to a fuel cell membrane humidifier and a fuel cell device. Background Art

[0002] Proton exchange membrane fuel cells are a new type of battery that uses proton exchange membrane as a medium. When working, it must maintain proper moisture to ensure battery performance and good proton conductivity. In actual application, when the humidity is low, the proton exchange membrane will dry out, the proton conduction ability of the proton exchange membrane will decrease, the resistance will increase, the voltage will drop, and the output power will decrease, which may cause the proton exchange membrane to rupture and affect the operation of the fuel cell; when the humidity is high, the water in the fuel cell cannot be discharged in time, the water content is too high, and flooding is prone to occur, which hinders the transmission of oxygen and reduces the performance of the battery. Therefore, the key to the normal operation of the proton exchange membrane fuel cell is to maintain the humidity of the proton exchange membrane.

[0003] To address this phenomenon, a gas humidification method is usually used to humidify the air before it enters the fuel cell. Common humidifiers include enthalpy wheel humidifiers and membrane humidifiers.

[0004] Membrane humidifiers have the advantages of relatively mature preparation technology, compact structure, small pressure drop and easy operation. However, since the part to be humidified and the moisture supply part are independent and relatively concentrated, the part to be humidified inside is often difficult to be effectively humidified, and the overall humidification is uneven, resulting in large differences in the humidity of the humidified gas supplied to the fuel cell stack, which in turn has a significant impact on the humidification effect, thereby greatly affecting the service life and performance of the entire fuel cell device. Summary of the invention

[0005] The object of the present invention is to provide a fuel cell membrane humidifier and a fuel cell device to solve the technical problem that the membrane humidifier of the fuel cell in the prior art humidifies the air unevenly, resulting in large differences in the humidity of the humidified gas supplied to the inside of the fuel cell stack, which in turn has a significant impact on the humidification effect, thereby greatly affecting the service life and performance of the entire fuel cell device.

[0006] In order to solve the above technical problems, the present invention specifically provides the following technical solutions:

[0007] A fuel cell membrane humidifier comprises an air inlet, a humidifying part and an air outlet which are connected in sequence; wherein:

[0008] The humidifying part is formed with a to-be-humidified gas passage and a wet hot water vapor passage from the inside to the outside, and the wet hot water vapor passage includes a steam inlet passage and a steam outlet passage connected to the outside;

[0009] The gas passage to be humidified includes a plurality of fiber membrane tubes extending from the air inlet to the air outlet, and the diameter of the fiber membrane tube located on the outside is greater than the diameter of the fiber membrane tube located on the inside.

[0010] As a preferred embodiment of the present invention, a flow direction from the steam inlet passage to the steam outlet passage is opposite to a flow direction from the air inlet portion to the air outlet portion.

[0011] As a preferred embodiment of the present invention, the plurality of fiber membrane tubes are evenly distributed on a plurality of circular rings formed with the midpoint of the humidifying section as the center, and the plurality of fiber membrane tubes distributed on the same circular ring form a membrane tube group.

[0012] As a preferred solution of the present invention, the number of fiber membrane tubes in the multiple groups of membrane tube groups gradually decreases from the outside to the inside.

[0013] As a preferred embodiment of the present invention, the ratio of the number of fiber membrane tubes in two adjacent groups of membrane tube groups is 1:1.5-2.5.

[0014] As a preferred embodiment of the present invention, each of the fiber membrane tubes is a double-layer structure, and the inner layer is a stainless steel screen, and the outer layer is at least one layer of aramid paper tube;

[0015] A gap extending in a wave shape is formed between the aramid paper tube and the stainless steel screen, and the depth and width of the wave shape in the gap in the plurality of fiber membrane tubes extending from the outside to the inside decrease sequentially along the extension direction.

[0016] As a preferred embodiment of the present invention, the humidifying section at least includes an outer shell, and the gas passage 31 to be humidified and the wet hot water vapor passage 32 are formed in the outer shell 36 from the inside to the outside, and the wet hot water vapor passage 32 forms a first buffer section, a humidifying section and a second buffer section in sequence along the steam inlet passage 33 and the steam outlet passage 34, and the diameter of the part of the outer shell 36 forming the first buffer section and the second buffer section is larger than the diameter of the part forming the humidifying section, and the inner walls of the two ends of the outer shell close to the air inlet section and the air outlet section extend inward along the axial direction of the outer shell to form baffles, and the baffles and the first buffer section and the second buffer section respectively enclose a gas buffer zone with an opening.

[0017] As a preferred solution of the present invention, the air inlet and the air outlet extend outward from the humidifying part to form a truncated cone structure.

[0018] In order to solve the above technical problems, the present invention further provides the following technical solutions:

[0019] A fuel cell device comprises a fuel cell membrane humidifier according to the above, wherein the air inlet is connected to an air supply assembly, and the air outlet and the steam inlet passage are respectively connected to a fuel cell stack.

[0020] As a preferred solution of the present invention, the air supply assembly includes an intercooler, an air compressor and an air filter structure which are sequentially connected to the air intake portion.

[0021] As a preferred solution of the present invention, the steam outlet passage is also connected to an exhaust gas emission structure.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1) By combining the steam inlet passage with the fuel cell stack, the water generated during the reaction of the fuel cell stack can enter the humidifying part through the steam inlet passage to humidify the air, thereby effectively recycling the water in the entire fuel cell device;

[0024] 2) By orderly setting the diameters of the fiber membrane tubes, the diameter of the fiber membrane tubes located on the outside is larger than the diameter of the fiber membrane tubes located on the inside, further forming a sparse to compact arrangement from the outside to the inside, so that the wet and hot water vapor passage located on the outside can effectively achieve progressive humidification in layers, and further complete the full humidification of the dry air. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0026] Figure 1 A schematic structural diagram of a fuel cell device provided in an embodiment of the present invention;

[0027] Figure 2 A schematic diagram of the internal structure of a fuel cell membrane humidifier provided by an embodiment of the present invention;

[0028] Figure 3 A cross-sectional view of a humidifying unit provided by an embodiment of the present invention;

[0029] Figure 4 A schematic structural diagram of a fuel cell membrane humidifier provided by an embodiment of the present invention;

[0030] Figure 5 A cross-sectional view of a fiber membrane tube provided in an embodiment of the present invention.

[0031] The numbers in the figure represent the following:

[0032] 1-air inlet; 2-air outlet; 3-humidification; 4-fuel cell stack; 5-intercooler; 6-air compressor; 7-air filter structure; 8-exhaust exhaust structure;

[0033] 30-seal pad; 31-gas passage to be humidified; 32-wet hot water vapor passage; 33-steam inlet passage; 34-steam outlet passage; 35-fiber membrane tube; 36-housing; 37-baffle; 38-gas buffer zone; 39-partition plate;

[0034] 351-stainless steel screen; 352-aramid paper tube; 353-gap. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] like Figure 1-Figure 4 As shown, the present invention provides a fuel cell membrane humidifier, comprising an air inlet 1, a humidifying part 3 and an air outlet 2 which are connected in sequence; wherein,

[0037] The humidifying part 3 is formed with a to-be-humidified gas passage 31 and a wet hot water vapor passage 32 from the inside to the outside, and the wet hot water vapor passage 32 includes a steam inlet passage 33 and a steam outlet passage 34 connected to the outside;

[0038] The humidified gas passage 31 includes a plurality of fiber membrane tubes 35 extending from the air inlet 1 to the air outlet 2 , and the diameter of the fiber membrane tubes 35 on the outside is larger than the diameter of the fiber membrane tubes 35 on the inside.

[0039] The hollow fiber membrane tube 35 is used to allow dry air to enter the fiber membrane tube 35 from the air inlet 1, and the humid hot water vapor in the external humid hot water vapor passage 32 exchanges humidity through the tube wall of the fiber membrane tube 35, and the moist air with humidity flows out from the air outlet 2, completing the humidification of the overall dry air. At the same time, based on the adjustment of the diameter of the fiber membrane tube 35, the overall arrangement from the outside to the inside is formed from sparse to compact, and the humid hot water vapor in the external humid hot water vapor passage 32 is further humidified layer by layer, so that the dry air in the inner and outer fiber membrane tubes 35 can be fully humidified.

[0040] Furthermore, the use of fiber membrane tubes 35 with through holes of different diameters can effectively improve gas distribution so that the entire humidification section 3 can humidify the dry gas evenly. The fiber membrane tubes 35 with large through hole diameters reduce the flow resistance of dry and wet gases and reduce the overall pressure drop. Compared with the structure with additional partitions, the internal structure is simplified, the internal space is saved, and the assembly efficiency and humidification performance are improved.

[0041] In a preferred embodiment of the present invention, the flow direction from the steam inlet passage 33 to the steam outlet passage 34 is opposite to the flow direction from the air inlet 1 to the air outlet 2. This arrangement allows the dry air and the humid hot water vapor to flow in reverse directions, thereby improving the humidification efficiency.

[0042] In another preferred embodiment of the present invention, the plurality of fiber membrane tubes 35 are evenly distributed on a plurality of circular rings formed with the midpoint of the humidifying part 3 as the center, and the plurality of fiber membrane tubes 35 distributed on the same circular ring form a membrane tube group. Such an arrangement can better guide the progressive humidification of the humid hot water vapor and effectively improve the humidification effect.

[0043] Furthermore, the number of fiber membrane tubes 35 in the multiple groups of membrane tube groups gradually decreases from the outside to the inside, and the ratio of the number of fiber membrane tubes 35 in two adjacent groups of membrane tube groups is 1:1.5-2.5. Based on such a setting, the whole presents a radial distribution state, and on the basis of decreasing diameter from the outside to the inside and decreasing number from the outside to the inside, the larger the diameter of the fiber membrane tube 35 close to the outside, the relatively sparser the distribution, and the smaller the diameter of the fiber membrane tube 35 close to the inside, the relatively compacter the distribution, so that in the process of humid hot water vapor flowing from the outside to the inside, it first passes through the fiber membrane tube 35 with a larger diameter, and then passes through the fiber membrane tube 35 with a smaller diameter, which can better make the dry air inside that is not easy to humidify effectively humidified, thereby improving the consistency of the internal and external humidification effects.

[0044] In a more preferred embodiment, each of the fiber membrane tubes 35 is a double-layer structure, and the inner layer is a stainless steel mesh 351 , and the outer layer is at least one layer of aramid paper tube 352 .

[0045] Of course, the fiber membrane tube 35 here is a cylindrical tubular structure as a whole, and the axial directions of the multiple fiber membrane tubes 35 are parallel to each other, and the adjacent fiber membrane tubes 35 are arranged at intervals. Further, a partition 39 is formed at both ends of the fiber membrane tube 35, and a through hole corresponding to the through holes of the multiple fiber membrane tubes 35 is formed on the partition 39. The through holes of the fiber membrane tube 35 correspond to the through holes, and the ends of the fiber membrane tube 35 are sealed and fixed on the partition 39 through the sealing pad 30.

[0046] Furthermore, the stainless steel screen 351 is wrapped with aramid paper, and then the aramid paper is fixed by stainless steel wire to form an aramid paper tube 352, and the aramid paper tube 352 and the internal stainless steel screen 351 are combined to form the fiber membrane tube 35. The number of layers of the aramid paper tube 35235 can be 1-5 layers, which can be determined according to the requirements of the sustained release effect and air permeability. Specifically, if a good dehumidification effect is required, 1-2 layers can be used; if strict air permeability is required, 4-5 layers can be used.

[0047] In the above scheme, aramid paper is used as the permeable membrane. Aramid paper is a special paper made by deep processing of aramid fiber. In addition to having excellent properties such as ultra-high strength, high modulus, high temperature resistance, flame retardancy, electrical insulation, acid and alkali resistance, and light weight, aramid paper has 5-6 times the strength of steel wire, 2-3 times the modulus of steel wire or glass fiber, 2 times the toughness of steel wire, and only about one-fifth the weight of steel wire. It has good chemical stability, abnormally stable chemical structure, excellent resistance to hydrolysis and steam corrosion, and good hygroscopicity. The moisture absorption of aramid paper can reach 2-10 times of its own weight. Therefore, there is no need to use expensive polymer membrane materials, and the cost is low; the effective area of ​​humidification and heating is large, the water vapor diffusion flux is high, the humidifier is efficient, and the volume is small; due to the low density of aramid paper, the weight of the fuel cell membrane humidifier of the present invention is light, especially for the application of automobiles, which is more beneficial for weight-sensitive occasions.

[0048] In a more preferred embodiment, a gap 353 extending in a wave shape is formed between the aramid paper tube 352 and the stainless steel screen 351, and the depth and width of the wave shape in the gap 353 in the multiple fiber membrane tubes 35 extending from the outside to the inside decrease sequentially along the extension direction. Of course, it is further explained that the wave shape here refers to the gap 353 in the cross section after cutting along the radial direction of the fiber membrane tube 35, which is formed into a wave shape, and the gap 353 of the entire wave-shaped cross section extends along the axial direction of the fiber membrane tube 35. The above-mentioned gap 353 is formed between the aramid paper tube 352 and the stainless steel screen 351 in each fiber membrane tube 35, and the wave formed by the cross section of the above-mentioned gap 353 in the multiple fiber membrane tubes 35 arranged from the outside to the inside decreases sequentially, specifically, it means that the depth and width thereof decrease sequentially. The setting of such a gap 353 further matches the structure of the corresponding fiber membrane tube 35 and the setting of the internal through holes, effectively and specifically reserves humidification space, and further improves the humidification uniformity and humidification effect. This wavy structure is formed by pressing the inner surface of the aramid paper tube 352 to form a wavy surface, and then wrapping it with a stainless steel screen 351.

[0049] In a more preferred embodiment of the present invention, the humidifying section 3 at least includes an outer shell 36, in which the gas passage 31 to be humidified and the wet hot water vapor passage 32 are formed from the inside to the outside, and the wet hot water vapor passage 32 forms a first buffer section, a humidifying section and a second buffer section in sequence along the steam inlet passage 33 and the steam outlet passage 34, and the diameter of the part of the outer shell 36 forming the first buffer section and the second buffer section is larger than the diameter of the part forming the humidifying section, and the inner walls of the two ends of the outer shell 36 close to the air inlet section 1 and the air outlet section 2 extend inward along the axial direction of the outer shell 36 to form baffles 37, and the baffles 37 and the first buffer section and the second buffer section respectively enclose a gas buffer zone 38 with an opening.

[0050] In another preferred embodiment of the present invention, the air inlet portion 1 and the air outlet portion 2 extend outward from the humidifying portion 3 to form a truncated cone structure.

[0051] In another aspect of an embodiment of the present invention, a fuel cell device is also provided, comprising a fuel cell membrane humidifier according to the above description, wherein the air inlet 1 is connected to an air supply component, and the air outlet 2 and the steam inlet passage 33 are respectively connected to a fuel cell stack 4.

[0052] In a further preferred embodiment, the air supply assembly includes an intercooler 5, an air compressor 6 and an air filter structure 7 which are sequentially connected to the air intake portion 1. Furthermore, the steam outlet passage 34 is also connected to an exhaust gas discharge structure 8.

[0053] Specifically, the whole humidification process is as follows:

[0054] The air enters the air compressor 6 for compression, and passes through the intercooler 5 to reduce the temperature of the pressurized air. The obtained dry air passes through the air intake 1 and enters the humidification part 3 for humidification. The humidified air passes through the air outlet 2 and enters the fuel cell stack 4 to react with hydrogen. The generated humid hot water vapor enters the humid hot water vapor passage 32 from the steam inlet passage 33 and humidifies the dry air in the gas passage 31 to be humidified. The excess dry water vapor passes through the steam outlet passage 34 and is discharged through the exhaust gas emission structure 8.

[0055] The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present application within the essence and protection scope of the present application, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present application.

Claims

1. A fuel cell membrane humidifier, characterized in that: It comprises an air inlet (1), a humidifying part (3) and an air outlet (2) which are connected in sequence; wherein: The humidifying part (3) is formed with a to-be-humidified gas passage (31) and a wet hot water vapor passage (32) from the inside to the outside, and the wet hot water vapor passage (32) includes a steam inlet passage (33) and a steam outlet passage (34) connected to the outside; The gas passage (31) to be humidified comprises a plurality of fiber membrane tubes (35) extending from the air inlet (1) to the air outlet (2), and the diameter of the fiber membrane tubes (35) located on the outside is larger than the diameter of the fiber membrane tubes (35) located on the inside; The plurality of fiber membrane tubes (35) are evenly distributed on a plurality of circular rings formed with the midpoint of the humidifying portion (3) as the center, and the plurality of fiber membrane tubes (35) distributed on the same circular ring form a membrane tube group; The number of fiber membrane tubes (35) in the plurality of membrane tube groups gradually decreases from the outside to the inside; The ratio of the number of fiber membrane tubes (35) in two adjacent groups of membrane tubes is 1:1.5-2.5; Each of the fiber membrane tubes (35) has a double-layer structure, with the inner layer being a stainless steel screen (351) and the outer layer being at least one layer of aramid paper tube (352); A gap (353) extending in a wave shape is formed between the aramid paper tube (352) and the stainless steel screen (351), and the depth and width of the wave shape in the gap (353) in the plurality of fiber membrane tubes (35) extending from the outside to the inside decreases sequentially along the extension direction; The air inlet (1) and the air outlet (2) extend outward from the humidifying portion (3) to form a truncated cone structure.

2. A fuel cell membrane humidifier according to claim 1, characterized in that: The flow direction from the steam inlet passage (33) to the steam outlet passage (34) is opposite to the flow direction from the air inlet portion (1) to the air outlet portion (2).

3. A fuel cell membrane humidifier according to claim 1 or 2, characterized in that: The humidifying section (3) comprises at least an outer shell (36), wherein the gas passage (31) to be humidified and the wet hot water vapor passage (32) are formed from the inside to the outside in the outer shell (36), and the wet hot water vapor passage (32) is sequentially formed into a first buffer section, a humidifying section and a second buffer section along the steam inlet passage (33) and the steam outlet passage (34), and the diameter of the portion of the outer shell (36) forming the first buffer section and the second buffer section is larger than the diameter of the portion forming the humidifying section, and the inner walls of the two ends of the outer shell (36) close to the air inlet section (1) and the air outlet section (2) extend inwardly along the axial direction of the outer shell (36) to form baffles (37), and the baffles (37) and the first buffer section and the second buffer section respectively enclose a gas buffer zone (38) with an opening.

4. A fuel cell device, characterized in that: It comprises a fuel cell membrane humidifier according to any one of claims 1 to 3, wherein the air inlet (1) is connected to an air supply component, and the air outlet (2) and the steam inlet passage (33) are respectively connected to a fuel cell stack (4).

5. A fuel cell device according to claim 4, characterized in that: The air supply assembly comprises an intercooler (5), an air compressor (6) and an air filter structure (7) which are sequentially connected to the air intake portion (1).

6. A fuel cell device according to claim 4 or 5, characterized in that: The steam outlet passage (34) is also connected to an exhaust gas exhaust structure (8).

Images