Asymmetric wettability flat sheet membrane humidifier and proton exchange membrane fuel cell humidification system
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-10
- Publication Date
- 2026-08-11
Smart Images
Figure CN122552564A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of fuel cell humidification technology, specifically to an asymmetric wettability flat sheet membrane humidifier and a proton exchange membrane fuel cell humidification system. Background Technology
[0002] In proton exchange membrane fuel cells (PEMFCs), the conductivity of the proton exchange membrane is linearly related to its hydration level. Therefore, humidifying the reactant gas is a key technology for achieving high energy conversion efficiency. Currently, external humidifiers are mainly used to maintain the humidity of the proton exchange membrane. The properties of the membrane material used in the humidifier determine its humidification efficiency and service life.
[0003] Existing flat-panel membrane humidifiers based on ion exchange membranes typically employ a bilateral symmetrical wettability design, where dry air and humid air exchange moisture directly through the membrane. This structure has the following technical problems: low water supply efficiency on the wet side, reliance on gaseous water diffusion, and limited mass transfer driving force; the bilateral symmetrical wettability design cannot simultaneously optimize both water supply and humidification processes.
[0004] Therefore, improving the water supply efficiency of humidifiers, reducing drainage resistance, and increasing mass transfer flux have become urgent problems to be solved. Summary of the Invention
[0005] Therefore, the purpose of this invention is to provide an asymmetric wettability flat sheet membrane humidifier and a proton exchange membrane fuel cell humidification system to solve the technical problems of low water supply efficiency, high drainage resistance, and limited mass transfer flux of existing humidifiers.
[0006] The present invention provides a proton exchange membrane fuel cell, comprising: alternately stacked membrane electrode units and flow field plate units, wherein the membrane electrode unit includes an ion exchange membrane, a first gas diffusion layer disposed on the wet side of the ion exchange membrane, and a second gas diffusion layer disposed on the dry side of the ion exchange membrane, the ion exchange membrane being an ultrathin film, the first gas diffusion layer being a hydrophilic treatment layer, and the second gas diffusion layer being a hydrophobic treatment layer, the membrane electrode unit and the flow field plate units located on both sides thereon forming a wet-side flow channel and a dry-side flow channel, respectively.
[0007] Preferably, the ion exchange capacity of the ion exchange membrane is ≥0.4 mmol / g.
[0008] Further preferably, the water contact angle θ1 of the first gas diffusion layer satisfies θ1≤60°; and the water contact angle θ2 of the second gas diffusion layer satisfies θ2≥120°.
[0009] More preferably, the pore sizes of the first gas diffusion layer and the second gas diffusion layer are between 0.01 μm and 10 μm.
[0010] Further preferably, the first gas diffusion layer is hydrophilic by hydrophilic modification; the second gas diffusion layer is hydrophobic by hydrophobic modification.
[0011] Further preferred, in the hydrophilic modification process, the hydrophilic agent in the hydrophilic modification solution includes one or more of perfluorosulfonic acid resin, polyvinyl alcohol, hydrophilic silica, and hydrophilic titanium dioxide; in the hydrophobic modification process, the hydrophobic agent in the hydrophobic modification solution includes one or more of polytetrafluoroethylene, polyvinylidene fluoride, or fluorinated ethylene propylene copolymer.
[0012] Further preferably, the hydrophilic modified liquid comprises a hydrophilic agent and a polar solvent, wherein the mass fraction of the hydrophilic agent is 1-5%, and the polar solvent is isopropanol, ethanol, or N,N-dimethylformamide.
[0013] Further preferably, the hydrophobic modified liquid comprises a hydrophobic agent and a dispersant, wherein the mass fraction of the hydrophobic agent is 3-30%, and the dispersant is the surfactant Triton X-100.
[0014] The present invention also provides a humidification system for a proton exchange membrane fuel cell, comprising the above-mentioned asymmetric wettable flat sheet membrane humidifier and a proton exchange membrane fuel cell, wherein the wet side flow channel of the asymmetric wettable flat sheet membrane humidifier is connected to the wet exhaust port of the proton exchange membrane fuel cell, and the dry side flow channel of the asymmetric wettable flat sheet membrane humidifier is connected to the air inlet of the proton exchange membrane fuel cell, forming an exhaust humidification circulation loop.
[0015] Preferably, the wet-side air intake and dry-side air intake in the asymmetric wettability flat sheet membrane humidifier are countercurrent.
[0016] The asymmetric wettability flat-sheet membrane humidifier provided by this invention has higher mass transfer flux, stronger water supply stability, and higher drainage efficiency, and can be applied to scenarios requiring gas humidification, such as hydrogen fuel cell vehicles and stationary power plants. The proton exchange membrane fuel cell humidification system provided by this invention can stably and efficiently humidify the proton exchange membrane fuel cell through the above-mentioned asymmetric wettability flat-sheet membrane humidifier, thereby achieving efficient energy conversion of the battery. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1 A schematic diagram of the structure of the asymmetric wettability flat sheet membrane humidifier provided by the present invention;
[0019] Figure 2 This is a schematic diagram of the humidification film electrode structure;
[0020] Figure 3 The graph shows the humidification stability test results of the flat sheet membrane humidifier provided by the present invention under different inlet air humidity conditions. Detailed Implementation
[0021] To enable those skilled in the art to more clearly understand the content disclosed in this invention, the invention will be further described in detail below. The following description and specific embodiments are only for illustrating the principles, features, and processes of this invention, and are intended to further explain the invention, not to limit its scope. All other embodiments obtained by those skilled in the art based on the implementation examples of this invention without inventive effort are within the protection scope of this invention.
[0022] According to Fick's law, the transmembrane water flux J = -D·dC / dx, where D represents the membrane diffusion coefficient, and dC / dx is the water concentration gradient within the membrane, determined by the difference in water activity Δa across the membrane. Therefore, maximizing Δa is key to improving flux. To maximize Δa and significantly enhance the mass transfer driving force, this invention employs an asymmetric design for the wettability of the gas diffusion layers on both sides of the ion exchange membrane. The wet side is hydrophilic, with its micropores forming a concave liquid surface. Based on the Kelvin equation ln(p / p0) = -2γV... m • cosθ / (rRT), the hydrophilic pores (solid-liquid contact angle θ < 90°, cosθ > 0) facilitate water vapor condensation, maintaining a liquid water film on the membrane surface, making the wet-side membrane activity a_wet ≈ 1. Simultaneously, the "reservoir effect" of the hydrophilic pores can buffer fluctuations in inlet air humidity. The dry side is hydrophobically treated, with its micropores forming a convex liquid surface. The hydrophobic pores (θ > 90°, cosθ < 0) ensure that the equilibrium vapor pressure p / p0 > 1, promoting liquid water evaporation and reducing the dry-side membrane activity a_dry. Through the asymmetric design of wettability on both sides, Δa = a_wet - a_dry is maximized, significantly improving the mass transfer driving force, as detailed below:
[0023] like Figure 1 As shown, the present invention provides an asymmetric wettability flat-sheet membrane humidifier, comprising: alternately stacked membrane electrode units 1 and flow field plate units 2, wherein, as Figure 2As shown, the membrane electrode unit 1 includes an ion exchange membrane 11, a first gas diffusion layer 12 disposed on the wet side of the ion exchange membrane 11, and a second gas diffusion layer 13 disposed on the dry side of the ion exchange membrane 11. The ion exchange membrane 11 is an ultrathin membrane, preferably with a thickness ≤15μm. The first gas diffusion layer 12 is a hydrophilic treatment layer, and the second gas diffusion layer 13 is a hydrophobic treatment layer. The membrane electrode unit 1 and the flow field plate units 2 located on both sides of it respectively form a wet-side flow channel 3 and a dry-side flow channel 4.
[0024] This asymmetric wettability flat-sheet membrane humidifier boasts higher mass transfer flux, stronger water supply stability, and higher drainage efficiency. Through an asymmetric wettability design with a hydrophilic wet side and a hydrophobic dry side, combined with an ultra-thin ion exchange membrane, the mass transfer flux is significantly improved compared to traditional air-to-air humidifiers. The capillary condensation effect and reservoir buffering effect of the hydrophilic wet side layer can maintain high membrane activity when the inlet air humidity fluctuates, improving the stability of the humidity of the humidified air. The convex liquid surface effect of the hydrophobic dry side layer can promote evaporation and improve the wetting ability of the dry side air.
[0025] As an improvement to the technical solution, the ion exchange membrane 11 has an ion exchange capacity ≥ 0.4 mmol / g, preferably 0.9-1.2 mmol / g. The ion exchange membrane 11 can be a proton exchange membrane or anion exchange membrane, preferably with a thickness δ of 3-15 μm.
[0026] As an improvement to the technical solution, the water contact angle θ1 of the first gas diffusion layer 12 satisfies θ1≤60°; the water contact angle θ2 of the second gas diffusion layer 13 satisfies θ2≥120°.
[0027] As an improvement to the technical solution, the pore size of the first gas diffusion layer 12 and the second gas diffusion layer 13 is between 0.01 μm and 10 μm.
[0028] The strength of the gas diffusion layer needs to be sufficient to support the ion exchange membrane so that it does not deform when it is in a flow channel with a groove width of ≤2mm and a pressure difference of ≤0.1MPa across the membrane.
[0029] As an improvement to the technical solution, the first gas diffusion layer 12 is hydrophilic by hydrophilic modification; the second gas diffusion layer 13 is hydrophobic by hydrophobic modification. Preferably, both the first gas diffusion layer 12 and the second gas diffusion layer 13 are carbon paper modified layers, wherein the initial thickness of the carbon paper is selected to be 100-300 μm; and the initial porosity is 70-85%.
[0030] As an improvement to the technical solution, in the hydrophilic modification process, the hydrophilic agent in the hydrophilic modification liquid includes one or more of perfluorosulfonic acid resin, polyvinyl alcohol, hydrophilic silica, and hydrophilic titanium dioxide; in the hydrophobic modification process, the hydrophobic agent in the hydrophobic modification liquid includes one or more of polytetrafluoroethylene, polyvinylidene fluoride, or fluorinated ethylene propylene copolymer.
[0031] As an improvement to the technical solution, the hydrophilic modified liquid contains a hydrophilic agent and a polar solvent, wherein the mass fraction of the hydrophilic agent is 1-5%, and the polar solvent is isopropanol, ethanol, or N,N-dimethylformamide.
[0032] As an improvement to the technical solution, the hydrophobic modified liquid contains a hydrophobic agent and a dispersant, wherein the mass fraction of the hydrophobic agent is 3-30%, and the dispersant is the surfactant Triton X-100.
[0033] The present invention also provides a humidification system for a proton exchange membrane fuel cell, comprising the above-mentioned asymmetric wettable flat sheet membrane humidifier and a proton exchange membrane fuel cell, wherein the wet side flow channel 3 of the asymmetric wettable flat sheet membrane humidifier is connected to the wet exhaust port of the proton exchange membrane fuel cell, and the dry side flow channel 4 of the asymmetric wettable flat sheet membrane humidifier is connected to the air inlet of the proton exchange membrane fuel cell, forming an exhaust humidification circulation loop.
[0034] This proton exchange membrane fuel cell humidification system can stably and efficiently humidify the proton exchange membrane fuel cell through the aforementioned asymmetric wettability flat sheet membrane humidifier, thereby achieving efficient energy conversion of the battery.
[0035] As an improvement to the technical solution, the wet-side air intake and dry-side air intake in the asymmetric wettability flat sheet membrane humidifier are in counter-current.
[0036] As an improvement to the technical solution, the operating temperature range of the asymmetric wettability flat sheet membrane humidifier is 20-100℃.
[0037] Example 1
[0038] Preparation of asymmetric wettability flat sheet membrane humidifier:
[0039] (1) Preparation of hydrophilic gas diffusion layer (first gas diffusion layer): Take commercially available carbon paper (Toray TGP-H-060), immerse it in isopropanol solution containing 3wt% perfluorosulfonic acid resin (Nafion) for 5 min, take it out and dry it at 60℃ for 2 h, and measure the contact angle θ1 = 30°.
[0040] (2) Preparation of hydrophobic gas diffusion layer (second gas diffusion layer): Take commercially available carbon paper (Toray TGP-H-060), immerse it in an aqueous solution containing 10wt% polytetrafluoroethylene emulsion (60% solid content), add 0.5wt% Triton X-100 dispersant, soak for 3min, take it out and dry it at 80℃, and then heat treat it at 350℃ for 20min. The contact angle θ2 was measured to be 120°.
[0041] (3) Membrane electrode unit assembly: Take a 12 μm thick perfluorosulfonic acid proton exchange membrane (EW = 1100 g / mol), place it between the hydrophilic gas diffusion layer and the hydrophobic gas diffusion layer, and hot press it for 3 min at 140 °C and 1 MPa to obtain the membrane electrode unit.
[0042] (4) Humidifier encapsulation: Stack 10 membrane electrode units and flow field plate units, set up wet side flow channels and dry side flow channels, and encapsulate with end plates to obtain membrane humidifier sample A1.
[0043] Performance testing:
[0044] Test conditions 1: wet side temperature 60℃, wet side inlet relative humidity 100%, dry side inlet temperature 50℃, relative humidity 10%, gas flow rate 2m / s.
[0045] Test results: Transmembrane water flux J = 3.2 × 10⁻⁶ -3 mol / m 2 ·s.
[0046] Test conditions 2: wet side temperature 60℃, wet side inlet relative humidity 50-100%, dry side inlet temperature 50℃, relative humidity 10%, gas flow rate 2m / s.
[0047] Test results: When the relative humidity at the wet-side inlet changes from 50% to 100%, the fluctuation range of the relative humidity at the dry-side outlet decreases significantly (e.g., Figure 3 (As shown).
[0048] Example 2
[0049] In the hydrophilic modification solution, a hydrophilic precursor (butyl titanate) with a concentration of 3% was added. After impregnation, it was first hydrolyzed in deionized water, and the rest was the same as in Example 1.
[0050] The hydrophilic contact angle θ1 was measured to be 10°, and the hydrophobic contact angle θ2 was measured to be 120°.
[0051] The flux of membrane humidifier sample A2 is 3.5 × 10⁻⁶. -3 mol / m 2 ·s.
[0052] Comparative Example
[0053] Both the hydrophilic and hydrophobic sides utilize the hydrophobic side gas diffusion layer (contact angle θ = 120°) from Example 1, with the rest identical to Example 1. The flux of the obtained membrane humidifier sample was measured to be 2.4 × 10⁻⁶. -3 mol / m²·s.
[0054] As can be seen from the examples and comparative examples: the flux of Examples 1-2 (3.2-3.5×10⁻⁶) -3 mol / m 2 The ·s) was significantly higher than that of the comparative example 1 bis-hydrophobic design (2.4 × 10). -3 mol / m 2 The results (·s) demonstrate the advantages of the asymmetric wettability design in this invention.
[0055] Finally, it should be further noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. An asymmetrically wettable flat sheet membrane humidifier characterized by, include: Alternating stacked membrane electrode units (1) and flow field plate units (2), wherein the membrane electrode unit (1) includes an ion exchange membrane (11), a first gas diffusion layer (12) disposed on the wet side of the ion exchange membrane (11) and a second gas diffusion layer (13) disposed on the dry side of the ion exchange membrane (11), the ion exchange membrane (11) is an ultrathin film, the first gas diffusion layer (12) is a hydrophilic treatment layer; the second gas diffusion layer (13) is a hydrophobic treatment layer, and the membrane electrode unit (1) and the flow field plate units (2) located on both sides thereon form a wet side flow channel (3) and a dry side flow channel (4), respectively.
2. The asymmetric wetting flat sheet membrane humidifier according to claim 1, wherein, The ion exchange capacity of the ion exchange membrane (11) is ≥0.4 mmol / g.
3. The asymmetric wetting flat sheet membrane humidifier according to claim 1, wherein, The water contact angle θ1 of the first gas diffusion layer (12) satisfies θ1≤60°; the water contact angle θ2 of the second gas diffusion layer (13) satisfies θ2≥120°.
4. The asymmetric wetting flat sheet membrane humidifier according to claim 1, wherein, The pore sizes of the first gas diffusion layer (12) and the second gas diffusion layer (13) are between 0.01 μm and 10 μm.
5. The asymmetric wetting flat sheet membrane humidifier according to claim 1, wherein, The first gas diffusion layer (12) is hydrophilic by hydrophilic modification; the second gas diffusion layer (13) is hydrophobic by hydrophobic modification.
6. The asymmetric wettability flat sheet membrane humidifier according to claim 5, characterized in that, In the hydrophilic modification process, the hydrophilic agent in the hydrophilic modification solution includes one or more of perfluorosulfonic acid resin, polyvinyl alcohol, hydrophilic silica, and hydrophilic titanium dioxide; in the hydrophobic modification process, the hydrophobic agent in the hydrophobic modification solution includes one or more of polytetrafluoroethylene, polyvinylidene fluoride, or fluorinated ethylene propylene copolymer.
7. The asymmetric wetting flat sheet membrane humidifier according to claim 5, wherein, The hydrophilic modified liquid contains a hydrophilic agent and a polar solvent, wherein the mass fraction of the hydrophilic agent is 1-5%, and the polar solvent is isopropanol, ethanol, or N,N-dimethylformamide.
8. The asymmetric wetting flat sheet membrane humidifier according to claim 5, wherein, The hydrophobic modified liquid contains a hydrophobic agent and a dispersant, wherein the mass fraction of the hydrophobic agent is 3-30%, and the dispersant is the surfactant Triton X-100.
9. A proton exchange membrane fuel cell humidification system, characterized by, The invention includes the asymmetric wettable flat-sheet membrane humidifier and the proton exchange membrane fuel cell as described in any one of claims 1-8, wherein the wet side flow channel (3) of the asymmetric wettable flat-sheet membrane humidifier is connected to the wet exhaust port of the proton exchange membrane fuel cell, and the dry side flow channel (4) of the asymmetric wettable flat-sheet membrane humidifier is connected to the air inlet of the proton exchange membrane fuel cell, forming an exhaust humidification circulation loop.
10. The proton exchange membrane fuel cell humidification system of claim 9, wherein, The wet-side air intake and dry-side air intake in the asymmetric wettability flat sheet membrane humidifier are in countercurrent.