Bipolar plate cathode side runner structure for PEM electrolytic bath

Abstract

The utility model belongs to the technical field of bipolar plates of PEM electrolytic baths, and particularly relates to a bipolar plate cathode side runner structure for a PEM electrolytic bath. According to the technical scheme, the bipolar plate cathode side runner structure for the PEM electrolytic bath comprises a polar plate, and a cathode flow field is arranged on the polar plate; the cathode flow field comprises a main flow channel area, the two sides of the main flow channel area are both communicated with flow channel merging areas, and the other sides of the flow channel merging areas are communicated with flow field outlets. The utility model provides a cathode side runner structure of a PEM electrolytic bath, which improves the drainage and degassing efficiency and the fluid uniformity.

Description

TECHNICAL FIELD

[0001] The utility model belongs to PEM electrolytic cell bipolar plate technical field, especially related to a bipolar plate cathode side runner structure for PEM electrolytic cell. BACKGROUND

[0002] Hydrogen energy has the advantages of zero carbon, high efficiency, storage, safety and controllability, and is an ideal path to achieve the double carbon goals of carbon neutralization and carbon peak. Renewable energy electrolysis of water to produce hydrogen is the core hydrogen production method for obtaining green hydrogen in the future, among which the proton exchange membrane (PEM) water electrolysis hydrogen production technology has the most development potential. PEM electrolytic cell has the characteristics of compact structure, small land occupation, high electrolysis efficiency and fast response, and has good adaptability with intermittent wind and light renewable fluctuating power sources, so it has become the focus of the industry.

[0003] The bipolar plate is one of the main components of the PEM electrolytic cell, and its flow field structure determines the proportion of the effective reaction area of the electrolytic cell and the uniformity of the electrolytic water distribution. In addition, it also has an important influence on the hydrogen production efficiency of the electrolytic cell, the current density distribution on the bipolar plate, the voltage consistency between the plates and many other indicators, thereby determining the working performance and service life of the entire electrolytic cell. By improving the flow field design, it is expected to strengthen the mass transfer, timely discharge of oxygen or hydrogen generated during the electrolysis process, reduce the mass transfer resistance, and thereby reduce the voltage loss. At the same time, optimizing the flow field structure can also strengthen heat transfer, take away heat, and improve the operating stability of the electrolytic cell.

[0004] At present, the flow channel design of the PEM electrolytic cell bipolar plate mainly focuses on the selection of the flow channel type on the anode side and the optimization of the flow channel geometry, while there are few reports on the optimization of the flow channel structure on the cathode side. When the PEM electrolytic cell is operated at high current density, the amount of hydrogen produced on the cathode side increases, and the water transported from the anode side to the cathode side by electroosmotic drag force also increases. If the excess water cannot be effectively removed from the cathode side flow field, it will reduce the electrolysis efficiency and increase the hydrogen crossover risk, thereby affecting the performance and safe operation of the electrolytic cell. Therefore, in addition to having good exhaust performance, the flow channel structure on the cathode side of the PEM electrolytic cell also needs to have good water management, which is particularly important for the performance stability and safety of the electrolytic cell at high current density. Utility model content

[0005] In order to solve the above problems existing in the prior art, the purpose of the utility model is to provide a PEM electrolytic cell cathode side flow channel structure, which improves the drainage and degassing efficiency and fluid uniformity.

[0006] The technical scheme adopted by the utility model is:

[0007] The utility model provides a bipolar plate cathode side runner structure for PEM electrolytic cell, including polar plate, be provided with cathode flow field on polar plate, the cathode flow field includes main runner area, and the both sides of main runner area are connected with runner merging area, and the other side of runner merging area is connected with flow field export.

[0008] In the traditional PEM electrolytic cell bipolar plate, the cathode side adopts a serpentine runner or a simple parallel runner. The utility model discloses a parallel runner of main runner area, and the design of the flow field export and the runner merging area of the upper and lower ends of the symmetrical cathode flow field greatly shortens the length of a single runner, and the cathode flow field contains two flow field exports, so that the drainage and degassing efficiency of the cathode side is significantly improved.

[0009] The utility model discloses a runner merging area, which can adjust the flow distribution of water-gas two-phase flow, improve the uniformity of the flow, and be beneficial to the uniformity of the temperature field distribution of the cathode side, thereby improving the performance stability and service life of the electrolytic cell.

[0010] As a preferred scheme of the utility model, the two flow field exports of the cathode flow field are in angular symmetry.

[0011] As a preferred scheme of the utility model, the flow field export of the upper end of the cathode flow field is located at the one-third position of the width of the cathode flow field from left to right, and the flow field export of the lower end of the cathode flow field is located at the two-thirds position of the width of the cathode flow field from left to right.

[0012] As a preferred scheme of the utility model, the flow field export is provided with n main runners, each runner is connected with two branch runners, the branch runners of the flow field export and the runners of the runner merging area are in one-to-one correspondence, and the runners of the runner merging area correspond to the runners of the main runner area; wherein n is an odd number.

[0013] If the number of the runners of the flow field export is n, then the number of the runners of the runner merging area is m (m=2n). The number of the runners of the main runner area is determined by the width of the polar plate, and the relationship is as follows: l=4+a (m-2)=4+2a (n-1); wherein a is an integer.

[0014] As a preferred scheme of the utility model, the runner width and ridge width of the branch runner of the flow field export are both 1-1.5mm.

[0015] As a preferred scheme of the utility model, the runner width and ridge width of the main runner area are both 1-1.5mm.

[0016] As the preferred scheme of the utility model, 2n flow channels of the flow channel merging area of the upper end of the cathode flow field are divided into two groups, n-1 flow channels on the left side are bent 90 degrees to the left side, and n+1 flow channels on the right side are bent 90 degrees to the right side.

[0017] As the preferred scheme of the utility model, the flow channel merging area is provided with a chamfer, and the two ends of the ridge of the main flow channel area are also provided with a chamfer.

[0018] As the preferred scheme of the utility model, the two flow channels on the left side of the main flow channel area are communicated with the left first flow channel of the flow channel merging area of the upper end of the cathode flow field, the two flow channels on the right side of the main flow channel area are communicated with the right last flow channel of the flow channel merging area of the lower end of the cathode flow field, and any one of the 2n-2 flow channels in the middle of the flow channel merging area is communicated with the flow channels of the main flow channel area.

[0019] As the preferred scheme of the utility model, the flow channel type of the main flow channel area is parallel flow channel or wave-shaped flow channel.

[0020] The utility model has the advantages of:

[0021] 1. The utility model discloses a parallel flow channel of the main flow channel area, which is matched with the design of the flow field outlet and the flow channel merging area of the upper and lower ends of the symmetrical cathode flow field, so that the length of a single flow channel is greatly shortened, and the drainage and degassing efficiency of the cathode side is significantly improved due to the two flow field outlets of the cathode flow field.

[0022] 2. The utility model discloses a flow channel merging area, which can adjust the flow distribution of water-gas two-phase flow, improve the uniformity of the flow, and be beneficial to the uniformity of the temperature field distribution of the cathode side, so as to improve the performance stability and service life of the electrolytic cell. DRAWINGS

[0023] Figure 1 It is a PEM electrolytic cell cathode side flow field structure schematic view.

[0024] Figure 2 It is a cathode side flow field structure diagram in the embodiment.

[0025] Figure 3 It is a PEM electrolytic cell cathode flow field upper end flow field outlet cathode liquid water volume fraction diagram.

[0026] Figure 4 It is a PEM electrolytic cell cathode flow field lower end flow field outlet cathode liquid water volume fraction diagram.

[0027] In the figure: 1-main flow channel area; 2-flow channel merging area; 3-flow field outlet; 4-first flow channel on the left side of the main flow field in the cathode flow field; 5-second flow channel on the left side of the main flow field in the cathode flow field; 6-first flow channel on the right side of the main flow field in the cathode flow field; 7-second flow channel on the right side of the main flow field in the cathode flow field. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in combination with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. The components of the embodiments of the utility model described and shown in the drawings can be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of the utility model provided in the drawings is not intended to limit the scope of the claimed utility model, but only represents selected embodiments of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the utility model. It should be noted that the embodiments in the utility model and the features in the embodiments can be combined with each other without conflict.

[0030] As Figure 1 shown, the PEM electrolytic cell bipolar plate cathode side flow channel structure of the utility model, including polar plate, polar plate on the cathode flow field is provided with;The cathode flow field includes main flow channel area 1, both sides of main flow channel area 1 are communicated with flow channel merging area 2, and the other side of flow channel merging area 2 is communicated with flow field outlet 3.The flow channel type of main flow channel area 1 is parallel flow channel or wave-shaped flow channel.

[0031] Figure 1 In the figure, the dashed part is main flow channel area 1;The thin solid line part is flow channel merging area 2, located at both ends of the flow field;The thick solid line part is flow field outlet 3, located at both ends of the flow field and at 1 / 3 width position of the flow field.

[0032] In the traditional PEM electrolytic cell bipolar plate, the cathode side adopts a serpentine flow channel or a simple parallel flow channel. The utility model greatly shortens the length of a single flow channel by parallel flow channel of main flow channel area 1, and the design of flow field outlet 3 and flow channel merging area 2 at the upper and lower ends of the symmetrical cathode flow field, and the cathode flow field contains two flow field outlets 3, so that the drainage and degassing efficiency of the cathode side is significantly improved.

[0033] The utility model discloses by setting flow channel merging area 2, can adjust the flow distribution of water-gas two-phase flow, improve the fluid uniformity, be beneficial to the distribution uniformity of cathode side temperature field, thereby improve the performance stability and life of electrolytic cell.

[0034] Furthermore, the two flow field outlets 3 of the cathode flow field are angularly symmetrical. The upper flow field outlet 3 of the cathode flow field is located at one-third of the width of the cathode flow field from left to right, and the lower flow field outlet 3 of the cathode flow field is located at two-thirds of the width of the cathode flow field from left to right.

[0035] Specifically, the flow field outlet 3 is provided with n main channels, each channel is connected to two branch channels, and the branch channels of the flow field outlet 3 are connected to the channels of the flow channel merging region 2 in a one-to-one correspondence. The channels of the flow channel merging region 2 are connected to the channels of several main channel regions 1; where n is an odd number.

[0036] If the number of flow channels at flow field outlet 3 is n, then the number of flow channels in flow channel merging region 2 is m (m = 2n). The number of flow channels l in main flow channel region 1 is determined by the width of the electrode plate, and has the following relationship: l = 4 + a(m-2) = 4 + 2a(n-1); where a is an integer.

[0037] The channel width and ridge width of the branch channel at the flow field outlet 3 are both 1 to 1.5 mm. The channel width and ridge width of the main channel region 1 are both 1 to 1.5 mm.

[0038] Furthermore, the 2n channels in the channel merging region 2 at the upper end of the cathode flow field are divided into two groups: the n-1 channels on the left bend 90° to the left, and the n+1 channels on the right bend 90° to the right; the 2n channels in the channel merging region 2 at the lower end of the cathode flow field are divided into two groups: the n-1 channels on the right bend 90° to the right, and the n+1 channels on the left bend 90° to the left.

[0039] The flow channel merging zone 2 has chamfered corners at all flow channel corners, and the ridge ends of the main flow channel zone 1 also have chamfered corners.

[0040] The two flow channels on the left side of the main flow channel region 1 are connected to the first flow channel on the left side of the flow channel merging region 2 at the upper end of the cathode flow field. The two flow channels on the right side of the main flow channel region 1 are connected to the last flow channel on the right side of the flow channel merging region 2 at the lower end of the cathode flow field. Any one of the 2n-2 flow channels in the middle of the flow channel merging region 2 is connected to several flow channels in the main flow channel region 1.

[0041] Example:

[0042] like Figure 2 As shown, the bipolar plate cathode-side flow channel structure for the PEM electrolyzer in this embodiment includes a cathode flow field disposed on the plate. The cathode flow field includes a main flow channel region 1, two flow channel merging regions 2, and two flow field outlets 3. The two flow channel merging regions 2 are respectively connected to the upper and lower sides of the main flow channel region 1. The upper flow field outlet 3 is connected to the upper side of the upper flow channel merging region 2, and the lower flow field outlet 3 is connected to the lower side of the lower flow channel merging region 2. The flow channel type of the main flow channel region 1 is a parallel flow channel.

[0043] Further, the flow field outlet 3 has 7 main flow channels and 14 sub-flow channels, each main flow channel is communicated with 2 sub-flow channels, and the number of main flow channels is determined by the width of the flow field.

[0044] Further, the flow channel merging area 2 has 14 flow channels. The first flow channel 4 on the left side of the main flow field in the cathode flow field and the second flow channel 5 on the left side of the main flow field in the cathode flow field are communicated, and are communicated with the first flow channel on the left side of the flow channel merging area 2 at the upper end of the cathode flow field. The first flow channel 6 on the right side of the main flow field in the cathode flow field and the second flow channel 7 on the right side of the main flow field in the cathode flow field are communicated, and are communicated with the first flow channel on the right side of the flow channel merging area 2 at the lower end of the cathode flow field. The two flow channel merging areas 2 are in angular symmetry. The flow channels of the flow channel merging area 2 are arranged to ensure the consistency of the flow channel length as much as possible.

[0045] Further, the relationship between the number of flow channels l of the main flow channel area 1 and the number of flow channels 2n of the flow channel merging area 2 is as follows: l = 4 + 2a(n-1); wherein a is an integer. In different embodiments, according to the width of the flow field, the number of flow channels of the main flow channel area 1, the number of flow channels of the flow channel merging area 2 and the number of main flow channels of the flow field outlet 3 are arranged.

[0046] In some embodiments, the two flow field outlets 3 are arranged in a diagonal line, and are turned through the flow channel merging area 2 so that the flow field outlets 3 are located on both sides of the flow field width, thereby reducing the material cost, while ensuring the consistency of the flow channel length as much as possible.

[0047] In some embodiments, the relationship between the liquid water volume fraction of the flow field outlet 3 and the time is simulated by using simulation software, as shown in Figure 3 and Figure 4 With the extension of the running time of the electrolytic cell, the liquid water volume fraction of the flow field outlet 3 reaches the maximum after 10 minutes and remains stable, and the liquid water volume fraction remains at about 0.15.

[0048] The utility model is not limited to the above optional implementation, anyone can draw other various forms of products under the enlightenment of the utility model, but no matter in its shape or structure makes any change, all technical solutions falling within the scope defined by the claims of the utility model, fall within the protection scope of the utility model.

Claims

1. A bipolar plate cathode side flow channel structure for a PEM electrolyzer, characterized by: The cathode flow field comprises a main flow channel area (1), both sides of the main flow channel area (1) are communicated with flow channel merging areas (2), and the other side of the flow channel merging areas (2) is communicated with flow field outlets (3).

2. The bipolar plate cathode side flow field structure for a PEM electrolyzer of claim 1, wherein: The two flow field outlets (3) of the cathode flow field are in angular symmetry.

3. The bipolar plate cathode side flow field structure for a PEM electrolyzer of claim 2, wherein: The flow field outlet (3) at the upper end of the cathode flow field is located at the one-third position of the width of the cathode flow field from left to right, and the flow field outlet (3) at the lower end of the cathode flow field is located at the two-thirds position of the width of the cathode flow field from left to right.

4. The bipolar plate cathode side flow field structure for a PEM electrolyzer of claim 1, wherein: The flow field outlet (3) is provided with n main flow channels, each flow channel is communicated with two branch flow channels, the branch flow channels of the flow field outlet (3) are communicated with the flow channels of the flow channel merging areas (2) one by one, and the flow channels of the flow channel merging areas (2) are communicated with the flow channels of the main flow channel areas (1).

5. The bipolar plate cathode side flow field structure for a PEM electrolyzer of claim 4, wherein: The flow channel width and ridge width of the branch flow channels of the flow field outlet (3) are both 1-1.5 mm.

6. The bipolar plate cathode side flow field structure for a PEM electrolyzer of claim 4, wherein: The flow channel width and ridge width of the main flow channel area (1) are both 1-1.5 mm.

7. The bipolar plate cathode side flow field structure for a PEM electrolyzer of claim 4, wherein: The 2n flow channels of the flow channel merging area (2) at the upper end of the cathode flow field are divided into two groups, the n-1 flow channels on the left side are bent to the left by 90°, and the n+1 flow channels on the right side are bent to the right by 90°; the 2n flow channels of the flow channel merging area (2) at the lower end of the cathode flow field are divided into two groups, the n-1 flow channels on the right side are bent to the right by 90°, and the n+1 flow channels on the left side are bent to the left by 90°.

8. The bipolar plate cathode side flow field structure for a PEM electrolyzer of claim 7, wherein: The flow channel turning angle areas of the flow channel merging areas (2) are all provided with chamfers, and the two ends of the ridges of the main flow channel area (1) are also provided with chamfers.

9. The bipolar plate cathode side flow field structure for a PEM electrolyzer of claim 4, wherein: The two flow channels on the left side of the main flow channel area (1) are communicated with the first flow channel on the left side of the flow channel merging area (2) at the upper end of the cathode flow field, the two flow channels on the right side of the main flow channel area (1) are communicated with the last flow channel on the right side of the flow channel merging area (2) at the lower end of the cathode flow field, and any one of the 2n-2 flow channels in the middle of the flow channel merging area (2) is communicated with the flow channels of the main flow channel area (1).

10. The bipolar plate cathode-side flow channel structure for a PEM electrolyzer according to any one of claims 1 to 9, characterized in that: The flow channel type of the main flow channel area (1) is parallel flow channel or wave-shaped flow channel.

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