A bipolar plate, an AEM electrolytic cell and a processing method of the bipolar plate
Patent Information
- Application Number
- CN202611135796.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-29
- Publication Date
- 2026-10-13
AI Technical Summary
目前市面上的AEM电解槽的双极板所采用的流道结构多为固定截面的平直流道、平行流道或简单蛇形流道，此类传统流道结构在实际应用过程中，存在传质效率低、气泡难以及时排出等技术缺陷
双极板的阳极面发生析氢反应，流体进入本申请实施例的双极板的阳极流道区，在相同的流量下，收缩段的流通截面积逐渐减小，流体的流速逐渐加快，扩张段的流通截面积逐渐增大，流体的流速逐渐变慢，因此流体在交替设置的收缩段和扩张段中流动时会周期性加速和减速。流体的流速变化能够增强流体扰动，破坏流体在流道的壁面形成的稳定边界层，使得流道的壁面附近的反应物浓度得到补充，由浓差极化造成的传质阻力减小。
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Figure CN122898906A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of AEM electrolytic cell technology, specifically to a bipolar plate, an AEM electrolytic cell, and a method for processing the bipolar plate. Background Technology
[0002] Anion exchange membrane (AEM) electrolyzers, as a highly efficient and environmentally friendly hydrogen production device, offer advantages such as high energy conversion efficiency, use of non-precious metal catalysts, high product purity, and environmental friendliness, making them promising candidates for application in the field of new energy hydrogen production. The bipolar plate, as one of the core components of the AEM electrolyzer, plays a crucial role in separating the electrolyte, conducting current, supporting the membrane electrodes, and distributing the reaction fluid. Its structural design directly affects the mass transfer efficiency, operational stability, energy consumption, and service life of the electrolyzer.
[0003] As the core functional area of the bipolar plate, the flow channel is the main channel for fluid transport and reaction. The flow channel structure is a key factor affecting the performance of the bipolar plate and even the entire AEM electrolyzer. Currently, the flow channel structures used in the bipolar plates of AEM electrolyzers on the market are mostly flat straight channels, parallel channels, or simple serpentine channels with fixed cross-sections. In practical applications, these traditional flow channel structures have technical defects such as low mass transfer efficiency and difficulty in timely removal of bubbles. Summary of the Invention
[0004] This application aims to solve at least one of the technical problems existing in the prior art. To this end, this application proposes a bipolar plate that can increase mass transfer efficiency, facilitate the discharge of bubbles generated in the reaction, and whose variable diameter flow channel is not easily deformed.
[0005] This application also proposes a method for processing an AEM electrolytic cell and bipolar plates.
[0006] According to the bipolar plate provided in the first aspect of the embodiments of this application, one side of the bipolar plate has an anode surface; An anode flow channel region is provided on the anode surface. The anode flow channel region has multiple variable diameter flow channels arranged at intervals. The variable diameter flow channels are used for fluid flow. The variable diameter flow channels include multiple expansion points and multiple contraction points. The expansion points and contraction points are arranged alternately along the flow direction of the fluid. Along the flow direction of the fluid, a contraction section of the variable diameter flow channel is formed between the expansion point and the next contraction point. The flow cross-sectional area of the contraction section gradually decreases. An expansion section of the variable diameter flow channel is formed between the contraction point and the next expansion point. The flow cross-sectional area of the expansion section gradually increases.
[0007] The bipolar plate according to the embodiments of this application has at least the following beneficial effects: Hydrogen evolution occurs at the anode surface of the bipolar plate. Fluid enters the anode flow channel region of the bipolar plate in this embodiment. At the same flow rate, the cross-sectional area of the contraction section gradually decreases, and the fluid velocity gradually increases; conversely, the cross-sectional area of the expansion section gradually increases, and the fluid velocity gradually decreases. Therefore, the fluid periodically accelerates and decelerates as it flows through the alternating contraction and expansion sections. This velocity variation enhances fluid turbulence, disrupts the stable boundary layer formed on the channel wall, replenishes the reactant concentration near the channel wall, and reduces the mass transfer resistance caused by concentration polarization.
[0008] Furthermore, the high fluid velocity in the contraction section generates strong shear force, which can be used to detach bubbles attached to the flow channel wall. After the bubbles are detached, they enter the expansion section, where the fluid velocity is slow and the local pressure decreases. This low-pressure environment causes an imbalance between the internal and external pressures of the bubbles, making large bubbles in the fluid easily break into multiple smaller bubbles. These smaller bubbles are easily carried out of the flow channel by the flowing fluid, thus achieving rapid bubble discharge and effectively preventing bubbles from clogging the flow channel.
[0009] According to some embodiments of this application, the anode flow channel region has multiple protruding ridges, and the sidewall contours on both sides of the ridges are continuous undulating curves, so that multiple peaks and multiple troughs are formed on the sidewalls of the ridges. The variable-diameter flow channel is formed between the opposite sidewalls of two adjacent ridges, the wave crests on the opposite sidewalls of two adjacent ridges are arranged opposite each other, and the contraction is formed between the oppositely arranged wave crests. The wave troughs on the opposite sidewalls of two adjacent ridges are arranged opposite each other, and the expansion is formed between the oppositely arranged wave troughs.
[0010] According to some embodiments of this application, the sidewalls on both sides of the spine are symmetrically arranged, the width of the spine corresponding to the trough of the spine is a first width W1, the width of the spine corresponding to the peak of the spine is a second width W2, the width of the expansion is W3, the width of the contraction is W4, W1:W3=1:2, W2:W4=2:1.
[0011] According to some embodiments of this application, an anode flow channel groove is provided on the anode surface, the ridge is disposed in the anode flow channel groove, the depth of the anode flow channel groove is greater than the height of the ridge, and a diffusion layer for placing an electrolytic cell is placed between the top of the anode flow channel groove and the upper surface of the ridge.
[0012] According to some embodiments of this application, the width W4 of the contraction portion is set to a range of 0.6mm to 0.8mm, and the width W3 of the expansion portion is set to a range of 1.0mm to 1.2mm; According to some embodiments of this application, the ratio of the flow cross-sectional area of the contraction portion to the expansion portion ranges from 1:1.2 to 1:1.8.
[0013] According to some embodiments of this application, the distance between adjacent expansion points and contraction points in the same variable diameter flow channel is L, and the expansion points and contraction points in the same variable diameter flow channel vary periodically with L, and the range of L is 8mm to 20mm.
[0014] According to some embodiments of this application, the depth of the variable diameter channel gradually decreases along the flow direction of the fluid.
[0015] According to some embodiments of this application, the anode surface is further provided with an anode inlet, an anode outlet, a first anode distribution area, and a second anode distribution area. The anode inlet and the anode outlet are respectively located at both ends of the anode flow channel area. The first anode distribution area is located between the anode inlet and the anode flow channel area, and the second anode distribution area is located between the anode inlet and the anode flow channel area.
[0016] According to some embodiments of this application, the first anode distribution region is arrayed with a plurality of first protrusions, and / or the second anode distribution region is arrayed with a plurality of second protrusions.
[0017] The AEM electrolytic cell provided according to the second aspect of the embodiments of this application includes: Multiple bipolar plates as described above are stacked together. In two adjacent bipolar plates, the anode surface of one bipolar plate is opposite to the cathode surface of the other bipolar plate, and a membrane electrode assembly is provided between them.
[0018] A method for processing a bipolar plate according to a third aspect of an embodiment of this application includes the following steps: Provide substrate; A photosensitive layer is coated on one side of the substrate. A preset pattern is transferred to the photosensitive layer by exposure, so that an exposed area corresponding to the preset pattern is formed on the photosensitive layer. The unexposed area of the photosensitive layer is removed by development. The unexposed areas on the surface of the substrate are etched to form variable diameter flow channels on the surface of the substrate; Remove the residual photosensitive layer from the surface of the substrate to obtain the anode surface of the bipolar plate.
[0019] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description
[0020] The accompanying drawings are used to provide a further understanding of the technical solutions disclosed in this application and form part of the specification. They are used together with the embodiments disclosed in this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions disclosed in this application.
[0021] Figure 1 This is a schematic diagram of the bipolar plate structure from a first perspective in an embodiment of this application; Figure 2 for Figure 1 Enlarged view of detail A in the middle; Figure 3 for Figure 1 A magnified view of detail B in the middle; Figure 4 This is a schematic diagram of the bipolar plate structure from a second perspective in an embodiment of this application; Figure 5 for Figure 4 Enlarged view of detail C in the middle; Figure 6 This is a schematic diagram of the cross-section of the variable diameter flow channel parallel to the fluid flow direction in an embodiment of this application; Figure 7 This is a partial structural schematic diagram of the AEM electrolytic cell in an embodiment of this application; Figure 8 The distribution of inlet flow rate between each channel in Comparative Example 1; Figure 9 The distribution of liquid inlet flow rate between each channel in Example 1; Figure 10 This is a flowchart of the bipolar plate processing method in the embodiments of this application.
[0022] Reference numerals: 100, anode surface; 110, anode flow channel area; 120, variable diameter flow channel; 130, ridge; 140, anode inlet; 150, anode outlet; 160, first anode distribution area; 161, first protrusion; 170, second anode distribution area; 200, cathode surface; 210, cathode inlet; 220, first cathode distribution area; 230, cathode flow channel area; 231, straight flow channel; 240, second cathode distribution area; 250, cathode outlet; 310, anode diffusion layer; 320, first cover plate; 330, second cover plate. Detailed Implementation
[0023] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.
[0024] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.
[0025] In the description of this application, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.
[0026] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.
[0027] In the description of this application, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0028] According to an embodiment of this application, an AEM electrolytic cell includes multiple bipolar plates stacked together. In two adjacent bipolar plates, the anode surface 100 of one bipolar plate is opposite to the cathode surface 200 of the other bipolar plate, and a membrane electrode assembly is provided between them.
[0029] After the AEM electrolyzer starts working, in two adjacent bipolar plates, the fluid (water) undergoes an oxygen evolution reaction at the anode surface 100 of one of the bipolar plates. Water molecules are oxidized to generate oxygen, hydrogen protons, and electrons. Oxygen is discharged in the form of bubbles from the variable-diameter flow channel 120 of the anode surface 100. Hydrogen protons pass through the anion exchange membrane in the membrane electrode assembly and migrate to the cathode surface 200 of the other bipolar plate. A hydrogen evolution reaction occurs in the cathode surface 200, and the generated hydrogen gas is discharged from the flow channel of the cathode surface 200.
[0030] like Figures 1 to 3As shown, according to an embodiment of the present application, the bipolar plate has an anode flow channel region 110 on its anode surface 100. The anode flow channel region 110 has a plurality of variable diameter flow channels 120 spaced apart. The variable diameter flow channels 120 are used for fluid flow. The variable diameter flow channels 120 include a plurality of expansion sections and a plurality of contraction sections. The expansion sections and contraction sections are arranged alternately in sequence along the flow direction of the fluid. Along the flow direction of the fluid, a contraction section of the variable diameter flow channel 120 is formed between the expansion section and the next contraction section. The flow cross-sectional area of the contraction section gradually decreases. An expansion section of the variable diameter flow channel 120 is formed between the contraction section and the next expansion section. The flow cross-sectional area of the expansion section gradually increases.
[0031] like Figure 2 As shown, Figure 2 The x-direction represents the flow direction of the fluid. The flow cross-sectional area is the cross-sectional area of the variable diameter channel 120 perpendicular to the flow direction.
[0032] During the operation of the AEM electrolyzer, fluid enters the anode flow channel region 110 of the bipolar plate in this embodiment of the application and participates in the oxygen evolution reaction at the anode. As the fluid passes through the variable-diameter flow channel 120, at the same flow rate, the flow cross-sectional area of the contraction section gradually decreases, and the fluid velocity gradually increases; conversely, the flow cross-sectional area of the expansion section gradually increases, and the fluid velocity gradually decreases. Therefore, the fluid periodically accelerates and decelerates as it flows through the alternating contraction and expansion sections. This change in fluid velocity enhances fluid turbulence, disrupts the stable boundary layer formed on the flow channel wall, and replenishes the reactant concentration near the flow channel wall. This ensures that the rate at which reactants are replenished to the membrane electrode assembly matches the rate at which reactants are consumed on the surface of the membrane electrode assembly, preventing concentration polarization on the membrane electrode assembly surface due to a lower reactant concentration than the bulk fluid solution concentration, ultimately reducing mass transfer resistance.
[0033] Furthermore, the high fluid velocity in the contraction section generates strong shear force, which can be used to detach bubbles attached to the channel wall. After the bubbles are detached, they enter the expansion section, where the fluid velocity is slow and the local pressure decreases. This low-pressure environment causes an imbalance between the internal and external pressures of the bubbles, making large bubbles with a diameter ≤500μm easily break into multiple smaller bubbles with a diameter ≤100μm. These smaller bubbles are easily carried out of the channel by the flowing fluid, thus achieving rapid bubble discharge and effectively preventing bubble blockage of the channel.
[0034] According to some embodiments of this application, such as Figures 1 to 3 As shown, multiple ridges 130 protrude from the anode flow channel region 110. The sidewall profiles on both sides of the ridges 130 are continuous undulating curves, so that multiple peaks and multiple troughs are formed on the sidewalls of the ridges 130. A variable-diameter flow channel 120 is formed between the opposite sidewalls of two adjacent ridges 130. The crests on the opposite sidewalls of two adjacent ridges 130 are arranged opposite each other, and a contraction is formed between the opposite crests. The troughs on the opposite sidewalls of two adjacent ridges 130 are arranged opposite each other, and an expansion is formed between the opposite troughs.
[0035] Because the AEM electrolytic cell of the large standard requires multiple bipolar plates and multiple membrane electrode assemblies to be stacked sequentially during the assembly process, and then pressed together. In the embodiment of this application, the sidewall contours of the bipolar plates on both sides of the spine 130 are continuous undulating curves. This structure enhances the load-bearing capacity of the spine 130, improves the overall mechanical rigidity and compressive strength of the bipolar plate, and the variable diameter flow channel 120 formed between adjacent spines 130 is not easily deformed during the assembly and pressing process.
[0036] According to some embodiments of this application, the sidewalls on both sides of the spine 130 are symmetrically arranged. The width of the spine 130 corresponding to the trough of the spine 130 is the first width W1, the width of the spine 130 corresponding to the peak of the spine 130 is the second width W2, the width of the expansion is W3, and the width of the contraction is W4. W1:W3=1:2, W2:W4=2:1.
[0037] According to some embodiments of this application, such as Figures 1 to 3 As shown, the width W4 of the contraction section is set to range from 0.6 mm to 0.8 mm, and the width W3 of the expansion section is set to range from 1.0 mm to 1.2 mm. The ratio of the flow cross-sectional area of the contraction section to the expansion section ranges from 1:1.2 to 1:1.8.
[0038] According to some embodiments of this application, the distance between adjacent expansion and contraction points in the same variable diameter flow channel 120 is L, and the expansion and contraction points in the same variable diameter flow channel 120 vary periodically with L, and the range of L is 8mm to 20mm.
[0039] like Figure 2 As shown, since the expansion and contraction sections in the same variable-diameter flow channel 120 change periodically with a velocity L, the fluid entering the variable-diameter flow channel 120 will periodically accelerate and decelerate as it flows through the alternating contraction and expansion sections. This periodic velocity change can enhance fluid turbulence, disrupt the stable boundary layer formed by the fluid on the channel wall, and replenish the reactant concentration near the channel wall, thus reducing the mass transfer resistance caused by concentration polarization. In some embodiments, L is set to 8 mm, 10 mm, 15 mm, 18 mm, or 20 mm.
[0040] like Figures 1 to 3As shown, preferably, the bipolar plate parameters in this embodiment are set as W1:W3=1:2, W2:W4=2:1, the flow cross-sectional area ratio of the contraction and expansion sections is set to 1:1.2, the width W4 of the contraction section is set to 0.8mm, and the width W3 of the expansion section is set to 1.2mm. In the fluid flow direction, the height of the ridge 130 gradually changes from 0.8mm to 0.4mm, and the expansion and contraction sections in the same variable diameter flow channel 120 change periodically with L=8mm. The above-mentioned bipolar plate has undergone strength testing and can withstand pressures of over 20MPa, exhibiting high overall rigidity and being less prone to warping deformation.
[0041] According to some embodiments of this application, such as Figure 6 As shown, the depth of the variable diameter channel 120 gradually decreases along the flow direction of the fluid.
[0042] The reference depth of the variable diameter flow channel 120 is set to D. Along the flow direction of the fluid, the depth of the variable diameter flow channel 120 continuously varies within the range of 30% to 70% of the reference depth D. Along the flow direction of the fluid, the depth of the variable diameter flow channel 120 decreases from 70%D to 30%D. As an example, the depth of the variable diameter flow channel 120 gradually changes from 0.8 mm to 0.4 mm.
[0043] The variable diameter flow channel 120 is designed with a depth-gradient structure. The inlet section of the variable diameter flow channel 120 is relatively deep, resulting in low fluid flow resistance and reduced pumping power consumption. Besides the impact of the periodic expansion and contraction of the variable diameter flow channel 120 on the fluid velocity, in this embodiment, the depth of the variable diameter flow channel 120 gradually decreases along the fluid flow direction. This depth gradient creates a fluid velocity gradient, causing the fluid velocity in the flow direction to gradually increase, generating strong shear force. This shear force can be used to peel off air bubbles attached to the flow channel wall, ensuring efficient bubble removal and discharge, achieving a compatible balance between flow resistance and bubble discharge efficiency.
[0044] According to some embodiments of this application, the anode surface 100 is further provided with an anode inlet 140, an anode outlet 150, a first anode distribution area 160 and a second anode distribution area 170. The anode inlet 140 and the anode outlet 150 are respectively disposed at both ends of the anode flow channel area 110; the first anode distribution area 160 is disposed between the anode inlet 140 and the anode flow channel area 110, and the second anode distribution area 170 is disposed between the anode inlet 140 and the anode flow channel area 110.
[0045] Specifically, in the actual operation of the AEM electrolyzer, the membrane electrode assembly includes an anode diffusion layer 310 and a cathode diffusion layer (not shown in the figure). The anode surface 100 of the bipolar plate is covered with the anode diffusion layer 310, and the cathode surface 200 of the bipolar plate is covered with the cathode diffusion layer. Fluid enters from the anode inlet 140, passes through the first anode distribution zone 160, and enters the anode flow channel zone 110. The fluid undergoes an oxygen evolution reaction in the anode flow channel zone 110. The oxygen generated by the reaction and the unreacted fluid are collected in the second anode distribution zone 170 and flow out through the anode outlet 150.
[0046] In large-format AEM electrolytic cells, the bipolar plates have a large area, which can easily lead to flow concentration and flow deviation at the anode inlet 140. The first anode distribution zone 160 in this application is a transition area connecting the anode inlet 140 and the anode flow channel region 110, and it can evenly distribute the fluid to the variable-diameter flow channels 120 within the anode flow channel region 110. The second anode distribution zone 170 is a transition area connecting the anode flow channel region 110 and the anode outlet 150, and it serves to collect and smoothly discharge the fluid.
[0047] In some embodiments, the first anode distribution area 160 and the second anode distribution area 170 are configured as a plurality of protrusions arranged in an array, or the first anode distribution area 160 and the second anode distribution area 170 are configured as a plurality of branch channels.
[0048] According to some embodiments of this application, such as Figures 1 to 3 As shown, a plurality of first protrusions 161 are arrayed in the first anode distribution area 160, and / or a plurality of second protrusions are arrayed in the second anode distribution area 170.
[0049] The width range of the first anode distribution area 160 and the second anode distribution area 170 is set to 15mm to 50mm.
[0050] Example 1: The width of the first anode distribution area 160 and the second anode distribution area 170 is 50 mm. The first protrusion 161 and the second protrusion are cylindrical, and the cross-sectional diameter of the first protrusion 161 and the second protrusion perpendicular to the axial direction is 2 mm. In the first anode distribution area 160, the axial distance between two adjacent first protrusions 161 is set to 3 mm. In the second anode distribution area 170, the axial distance between two adjacent second protrusions is set to 3 mm. The fluid passing through the first protrusions 161 and the second protrusions forms natural turbulence, which enables the fluid to be evenly distributed to each variable diameter flow channel 120.
[0051] Comparative Example 1: The only difference between Comparative Example 1 and Example 1 is that the first anode distribution area 160 in Comparative Example 1 does not have a first protrusion 161, and the second anode distribution area 170 does not have a second protrusion.
[0052] like Figure 8 and Figure 9 As shown, Figure 8 To use the inlet flow rate distribution results between the channels of Comparative Example 1, Figure 9 This shows the distribution of inlet flow rate between the channels in Example 1. Figure 8 As shown, the horizontal axis represents the channel number of the variable diameter flow channel 120, and the vertical axis represents the water mass flow rate in kg / s. Each data point represents the water mass flow rate value tested for different channels in Comparative Example 1. Figure 8 It can be seen that the flow rate fluctuation range of the first anode distribution zone 160 in Comparative Example 1 is -6.60% to 5.65%. The data points are highly dispersed around the mean, and the flow rate of some channels deviates significantly from the mean. This indicates that the uniformity of the liquid inlet flow rate in each channel under the distribution method of Comparative Example 1 is generally poor, which will affect the stability of the subsequent process.
[0053] like Figure 9 As shown, the horizontal axis represents the channel number of the variable diameter flow channel 120, and the vertical axis represents the water mass flow rate in kg / s. Each data point represents the water mass flow rate value tested for different channels in Example 1. Figure 9 It can be seen that the flow fluctuation range of the first anode distribution zone 160 in Example 1 is only -2.43% to 3.20%, and the dispersion of data points around the mean is small, compared to Figure 8 , Figure 9 The distribution of data points is more concentrated and the overall fluctuation is smaller, indicating that compared with Comparative Example 1, Example 1 has better uniformity of liquid inlet flow rate in each channel and more balanced flow distribution.
[0054] Further flow channel flow simulation calculations were performed on Example 1 and Comparative Example 1 respectively. In Example 1, the difference in inlet flow rate between each flow channel was less than 5%, and the difference in flow distribution between each flow channel was controlled within 10%, which ensured the uniform distribution of fluid in the flow channel and effectively avoided the problem of uneven fluid distribution and local fluid accumulation in the flow channel, which led to local hot spots on the membrane electrode.
[0055] According to some embodiments of this application, such as Figure 1 and Figure 7 As shown, the anode surface 100 has an anode flow channel groove, which forms an anode flow channel region 110. The bottom of the anode flow channel groove has a protruding ridge 130. The depth of the anode flow channel groove is greater than the height of the ridge 130. An accommodating space is formed between the top of the anode flow channel groove and the top of the ridge 130. The accommodating space is used to place the anode diffusion layer 310 of the electrolytic cell.
[0056] In an AEM electrolyzer, the membrane electrode assembly includes an anode diffusion layer 310, an anode catalyst layer, an anion exchange membrane, a cathode catalyst layer, and a cathode diffusion layer stacked sequentially. The anode surface 100 of the bipolar plate is attached to the anode diffusion layer 310, and the anode diffusion layer 310 is in contact with the fluid within the variable-diameter flow channel 120 of the bipolar plate. In this embodiment, the anode surface 100 is recessed to a certain depth to form an anode flow channel groove, and a ridge 130 is disposed within the anode flow channel groove. A receiving space is formed between the top of the anode flow channel groove and the top of the ridge 130. This receiving space can form a positioning structure for the anode diffusion layer 310, facilitating rapid alignment of the anode diffusion layer 310 and the bipolar plate during assembly, thus improving the assembly efficiency of the electrolyzer. No additional positioning structure needs to be designed on the bipolar plate, further simplifying the structural design of the bipolar plate.
[0057] Furthermore, the difference between the depth of the anode flow channel groove and the height of the ridge 130 is set to be 0.3–0.8 mm. It can be understood that the depth of the anode flow channel groove is designed according to the thickness of the anode diffusion layer 310 of the electrolytic cell, so that after the anode diffusion layer 310 is placed in the accommodating space, the top of the anode diffusion layer 310 is exactly flush with the anode surface 100.
[0058] like Figure 1 As shown, according to some embodiments of this application, the anode surface 100 is further provided with a first anode distribution groove and a second anode distribution groove. The first anode distribution groove and the second anode distribution groove are respectively disposed at both ends of the anode flow channel groove along the fluid flow direction. The first anode distribution groove is connected to the anode flow channel groove and forms a first anode distribution area 160. The second anode distribution groove is connected to the anode flow channel groove and forms a second anode distribution area 170.
[0059] A first protrusion 161 is disposed within a first anode distribution groove, the depth of which is less than the height of the first protrusion 161. The first anode distribution groove is used to house a first cover plate 320, which is placed on top of the first protrusion 161. A second protrusion is disposed within a second anode distribution groove, the depth of which is less than the height of the second protrusion. The second anode distribution groove is used to house a second cover plate 330, which is placed on top of the second protrusion. The first cover plate 320 and the second cover plate 330 both seal the opening of the first anode distribution groove, preventing fluid overflow.
[0060] According to some embodiments of this application, such as Figure 4 and Figure 5As shown, the side of the bipolar plate opposite to the anode surface 100 has a cathode surface 200. The cathode surface 200 is provided with a cathode flow channel region 230, a cathode inlet 210, a cathode outlet 250, a first cathode distribution region 220 and a second cathode distribution region 240. The cathode inlet 210 and the cathode outlet 250 are respectively located at both ends of the cathode flow channel region 230. The first cathode distribution region 220 is located between the cathode inlet 210 and the cathode flow channel region 230, and the second cathode distribution region 240 is located between the cathode inlet 210 and the cathode flow channel region 230.
[0061] According to some embodiments of this application, the anode flow channel region 110 has a plurality of horizontally spaced straight channels 231, the cross-sectional area of which remains constant. Since the cathode surface 200 of the bipolar plate typically only has gas flow, designing the anode flow channel region 110 as a horizontally spaced straight channel 231 can reduce the processing difficulty and cost of the bipolar plate.
[0062] According to some embodiments of this application, such as Figure 1 As shown, the aspect ratio of the bipolar plate is set to 3:2. The specific proportions and dimensions of the bipolar plate can be matched according to the actual hydrogen production.
[0063] like Figure 10 As shown, the processing method of the bipolar plate according to an embodiment of this application includes the following steps: S100: Provides a substrate; The substrate is made of 316L stainless steel, carbon steel or pure nickel. If stainless steel or carbon steel is selected as the base material, the substrate surface needs to be nickel plated to improve the bipolar plate's resistance to alkali corrosion in the alkaline environment of the AEM electrolytic cell.
[0064] The substrate is formed by machining or etching processes. Specifically, the etching process includes the following steps: S200: A photosensitive layer is deposited on one side of the substrate. A preset pattern is transferred to the photosensitive layer through exposure, so that an exposure area corresponding to the preset pattern is formed on the photosensitive layer. The unexposed area of the photosensitive layer is removed by development. S300: Etching the unexposed area on the substrate surface to form a variable diameter flow channel 120 on the substrate surface; S400: Remove the residual photosensitive layer on the substrate surface to obtain the anode surface 100 of the bipolar plate.
[0065] S500: A photosensitive layer is placed on the other side of the substrate. A preset pattern is transferred to the photosensitive layer through exposure, so that an exposure area corresponding to the preset pattern is formed on the photosensitive layer. The unexposed area of the photosensitive layer is removed by development. S600: Etches the unexposed areas on the substrate surface to form a flat DC channel 231 on the substrate surface.
[0066] S700: Remove the residual photosensitive layer on the substrate surface to obtain the cathode surface 200 of the bipolar plate.
[0067] The bipolar plate processing method of this application embodiment is used to process the bipolar plate as described above. The bipolar plate prepared by it can increase the mass transfer efficiency, facilitate the discharge of bubbles generated in the reaction, and its flow channel is not easily deformed.
[0068] In some alternative embodiments, the functions / operations mentioned in the block diagrams may not occur in the order shown in the operation diagrams. For example, depending on the functions / operations involved, two consecutively shown blocks may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order. Furthermore, the embodiments presented and described in the flowcharts of this application are provided by way of example to provide a more comprehensive understanding of the technology. The disclosed methods are not limited to the operations and logic flows presented herein. Alternative embodiments are contemplated in which the order of various operations is changed and sub-operations described as part of a larger operation are executed independently.
[0069] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application. Furthermore, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other.
Claims
1. A bipolar plate, characterized in that, One side of the bipolar plate has an anode surface; An anode flow channel region is provided on the anode surface. The anode flow channel region has multiple variable diameter flow channels arranged at intervals. The variable diameter flow channels are used for fluid flow. The variable diameter flow channels include multiple expansion points and multiple contraction points. The expansion points and contraction points are arranged alternately along the flow direction of the fluid. Along the flow direction of the fluid, a contraction section of the variable diameter flow channel is formed between the expansion point and the next contraction point. The flow cross-sectional area of the contraction section gradually decreases. An expansion section of the variable diameter flow channel is formed between the contraction point and the next expansion point. The flow cross-sectional area of the expansion section gradually increases.
2. The bipolar plate according to claim 1, characterized in that, The anode flow channel region has multiple protruding ridges, and the sidewalls on both sides of the ridges are continuous undulating curves, so that multiple peaks and multiple troughs are formed on the sidewalls of the ridges. The variable-diameter flow channel is formed between the opposite sidewalls of two adjacent ridges, the wave crests on the opposite sidewalls of two adjacent ridges are arranged opposite each other, and the contraction is formed between the oppositely arranged wave crests. The wave troughs on the opposite sidewalls of two adjacent ridges are arranged opposite each other, and the expansion is formed between the oppositely arranged wave troughs.
3. The bipolar plate according to claim 2, characterized in that, The sidewalls on both sides of the spine are symmetrically arranged. The width of the spine corresponding to the trough of the spine is the first width W1, the width of the spine corresponding to the peak of the spine is the second width W2, the width of the expansion is W3, and the width of the contraction is W4. W1:W3=1:2, W2:W4=2:
1.
4. The bipolar plate according to claim 1, characterized in that, The width W4 of the contraction section is set to a range of 0.6mm to 0.8mm, and the width W3 of the expansion section is set to a range of 1.0mm to 1.2mm; The ratio of the flow cross-sectional area of the contraction point to the expansion point is in the range of 1:1.2 to 1:1.
8.
5. The bipolar plate according to claim 1, characterized in that, The distance between adjacent expansion and contraction points in the same variable diameter flow channel is L. The expansion and contraction points in the same variable diameter flow channel vary periodically with L as the period, and the range of L is 8mm to 20mm.
6. The bipolar plate according to claim 1, characterized in that, The depth of the variable diameter flow channel gradually decreases along the flow direction of the fluid.
7. The bipolar plate according to claim 1, characterized in that, The anode surface is further provided with an anode inlet, an anode outlet, a first anode distribution area, and a second anode distribution area, with the anode inlet and the anode outlet respectively located at both ends of the anode flow channel area; The first anode distribution area is disposed between the anode inlet and the anode flow channel area, and the second anode distribution area is disposed between the anode inlet and the anode flow channel area.
8. The bipolar plate according to claim 7, characterized in that, The first anode distribution area is arrayed with a plurality of first protrusions, and / or the second anode distribution area is arrayed with a plurality of second protrusions.
9. An AEM electrolytic cell, characterized in that, include: A plurality of bipolar plates as described in any one of claims 1 to 8, wherein the bipolar plates are stacked, and in two adjacent bipolar plates, the anode surface of one bipolar plate is disposed opposite to the cathode surface of the other bipolar plate, and a membrane electrode assembly is provided between them.
10. A method for processing a bipolar plate as described in any one of claims 1 to 8, characterized in that, Including the following steps: Provide substrate; A photosensitive layer is coated on one side of the substrate. A preset pattern is transferred to the photosensitive layer by exposure, so that an exposed area corresponding to the preset pattern is formed on the photosensitive layer. The unexposed area of the photosensitive layer is removed by development. The unexposed areas on the surface of the substrate are etched to form variable diameter flow channels on the surface of the substrate; Remove the residual photosensitive layer from the surface of the substrate to obtain the anode surface of the bipolar plate.