Fuel cell pole plate and design method thereof

Abstract

The invention relates to a fuel cell polar plate and a design method thereof. An inlet confluence outlet and a confluence inlet of the fuel cell polar plate are diagonally arranged relative to an active part; the confluence outlet and the confluence inlet are both connected with a mixing part with a smooth surface; the mixing part is communicated with the flow channel of the active part through the shunting part; a plurality of ridges extending towards the active part are arranged on the surface of the shunting part, and each ridge is of a convex structure and is used for supporting a membrane electrode; a sub-runner is formed between every two adjacent ridges in a sunken manner; wherein the additionally arranged mixing part with the smooth surface realizes flow equalization by utilizing a fluid self-diffusion effect in a volume expanding manner, reduces the flow velocity through a runner-free cavity structure, realizes self-flow equalization by utilizing fluid inertia, reduces the speed, and enables water drops to be settled and separated by gravity; in addition, different shunting runners are arranged according to different parts of the active part, so that the unevenness of the active part is controlled within a reasonable fluctuation range.

Description

Technical Field

[0001] This application relates to the field of fuel cells, and in particular to a fuel cell electrode plate and its design method. Background Technology

[0002] Currently, hydrogen energy possesses clean and pollution-free chemical properties; its utilization can not only achieve energy storage but also ensure the diversity and stability of power supply in future industries. Proton exchange membrane fuel cells (PEMFCs) are simple in composition, compact in structure, lightweight, and portable; they directly generate low-voltage direct current through electrochemical reactions, have high operating current, and high specific power; they also offer advantages such as rapid start-up, low-temperature operation, high power density, and zero emissions.

[0003] During the reaction, the bipolar plates serve to separate and guide the gas, conduct electricity, provide support, dissipate heat, and drain water. A reasonable flow field structure can ensure that the reacting gases in the battery react fully and are evenly distributed, avoid local overheating of the battery, and drain the water generated in the reaction in a timely manner.

[0004] In existing hydrogen fuel cell single-cell or bipolar plate structures, fluid enters the splitting zone through the overflow port (gathering port), and after gas distribution in the splitting zone, it enters the active section to undergo an electrochemical reaction and generate electricity. However, this process has the following problems: The overpass is directly connected to the diversion zone. The airflow entering from the overpass is high-speed and concentrated, which directly impacts the diversion zone and causes overload in the first flow channel and insufficient air supply in the last flow channel. In addition, water droplets carried by the high-speed airflow are easy to collide and accumulate at the entrance of the diversion zone, causing local water blockage. Summary of the Invention

[0005] This application provides a fuel cell electrode plate and its design method to solve the problem in related technologies where the overpass is directly connected to the diversion zone, the airflow entering from the overpass is high-velocity and concentrated in direction, and the direct impact on the diversion zone will cause overload of the flow channel at the beginning of the diversion zone and insufficient air supply to the flow channel at the end.

[0006] In a first aspect, a fuel cell electrode plate is provided, comprising: Active part; Convergence point; The confluence outlet is diagonally positioned relative to the confluence inlet relative to the active part; both the confluence outlet and the confluence inlet are connected to a smooth-surfaced mixing section; the mixing section is connected to the flow channel of the active part through a diversion section; The surface of the shunt section is provided with multiple ridges extending toward the active section. The ridges are convex structures used to support the membrane electrode. The shunt channels are formed by recesses between adjacent ridges.

[0007] In some embodiments, the width of a single branch channel is less than or equal to 5 times the spine width and greater than or equal to 0.5 times the spine width.

[0008] In some embodiments, the plurality of said spines form a primary diversion channel, a secondary diversion channel, a tertiary diversion channel, and a quaternary diversion channel; The primary diversion channel has one inlet channel and one outlet channel; the secondary diversion channel has one inlet channel and two outlet channels; the tertiary diversion channel has one inlet channel and three outlet channels; and the quaternary diversion channel has one inlet channel and four outlet channels. The primary diversion channel is connected to the core reaction zone where the flow demand of the active part is constant; the secondary diversion channel is connected to the region of the active part where high flow uniformity is required; the tertiary and quaternary diversion channels are connected to the edge region of the electrode plate of the active part.

[0009] In some embodiments, in all primary diversion channels, some of the primary diversion channels are directly connected to the mixing section and the active section, while the remaining parts are connected to the secondary diversion channels; In all the secondary flow channels, some of the secondary flow channels are directly connected to the active part at their outlets, while the rest are connected to the tertiary flow channels; the tertiary flow channels are connected to the quaternary flow channels, and the quaternary flow channels are connected to the active part.

[0010] In some embodiments, in all primary diversion channels, some of the primary diversion channels are directly connected to the mixing section and the active section, while the remaining parts are connected to tertiary or quaternary diversion channels.

[0011] In some embodiments, the inlet channel of the secondary branch channel is d1, and the two branch channels are d3 and d4, respectively; wherein the width and included angle dimensions are configured as follows: d1=(1-1.1)×d4, d2=(1-1.1)×d4, d3=d4, and the included angle between d1 and d3 is >150°, and d2 is the first connecting transition channel at the junction of d4 and d1; The inlet channel of the three-stage branch channel is d1, and the three branch channels are d3, d4 and d5. The width and included angle dimensions are configured as follows: d1=(1.4-1.6)×d5, d2=(1.1-1.15)×d5, d6=(1-1.1)×d5, d3=d4=d5, and the included angle between d1 and d3 is greater than 150°. d6 is the second connecting transition channel at the junction of d5 and d2. The inlet channel of the four-stage branch flow channel is d1, and the four branch channels are d3, d4, d5 and d7. The width and included angle dimensions are configured as follows: d1=(1.7-1.8)×d7, d2=(1.2-1.3)×d7, d6=(1-1.1)×d7, d8=(0.6-0.7)×d7, d3=d4=d5=d7, and the included angle between d1 and d3 is greater than 150°. d8 is the third connecting transition channel at the junction of d7 and d6.

[0012] Secondly, a design method for fuel cell electrode plates is provided, comprising: Obtain the width of the shunt flow channel, establish a fuel cell electrode model, and then number the first-level, second-level, third-level, and fourth-level shunt flow channels according to their hierarchy. Based on the number of flow channels and flow distribution requirements of the active section, and referring to the hierarchical number, calculate the theoretical flow rate corresponding to each level of flow channel; Fluid simulation experiments were conducted on the established fuel cell plate model to obtain the actual flow distribution of each branch channel. Adjustments are made based on the actual flow distribution and corresponding theoretical flow of each branch channel, and then the simulation experiment is repeated until the flow non-uniformity of the active part is less than the first design value, and the flow of the channel with the number of edge targets is greater than the second design value.

[0013] In some embodiments, adjustments are made based on the actual flow distribution and corresponding theoretical flow of each branch channel, specifically including the following steps: The width of the branch channel, the angle between the branch channel and the corresponding main channel, and the radius of curvature between the branch channel and the corresponding main channel are adjusted according to the deviation between the actual flow distribution and the corresponding theoretical flow of each branch channel.

[0014] In some embodiments, in the secondary, tertiary, and quaternary branch channels, the corresponding channel width is calculated based on the number of channels in the active part corresponding to the branch channel.

[0015] In some embodiments, the calculation of the width of the branch channel further includes the following steps: In the secondary, tertiary, and quaternary branch flow channels, if the number of flow channels corresponding to the active parts of the branch flow channels is the same, then the width of the branch flow channels is the same. In a four-stage branched flow channel, the width of each branch channel is the same; If there is a flow channel in each branch flow channel that has fewer active sections than other branch flow channels, then the width of that flow channel is 70%-80% of the width of the other branch flow channels.

[0016] The beneficial effects of the technical solution provided in this application include: This application provides a fuel cell electrode plate and its design method. The inlet and outlet are diagonally positioned relative to the active part. Both the inlet and outlet are connected to a smooth-surfaced mixing section. The mixing section is connected to the flow channel of the active part via a branch section. The branch section has multiple ridges extending towards the active part, each ridge being a raised structure used to support the membrane electrode assembly. A branch channel is formed by recesses between adjacent ridges. The added smooth-surfaced mixing section achieves flow uniformity through the self-diffusion effect of the fluid by increasing its volume. It reduces the flow velocity through a channelless cavity structure and achieves self-flow uniformity through fluid inertia, thus reducing the velocity and allowing water droplets to separate due to gravity sedimentation. Furthermore, different branch channels are provided for different parts of the active part to control the non-uniformity of the active part within a reasonable fluctuation range. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the fuel cell electrode structure provided in an embodiment of this application; Figure 2 This is a schematic diagram of the structure of different flow channels of the flow divider provided in the embodiments of this application; Figure 3 A schematic diagram of a two-stage flow channel provided in an embodiment of this application; Figure 4 A schematic diagram of a three-stage flow channel provided in an embodiment of this application; Figure 5 A schematic diagram of a four-stage flow channel provided in an embodiment of this application; Figure 6 A schematic diagram illustrating the simple numbering and differentiation of different levels of diversion channels provided in the embodiments of this application; Figure 7 This is a schematic diagram of the flow channel structure of the actual battery electrode structure provided in the embodiments of this application; Figure 8 This application provides a schematic diagram of flow rate verification at each level under the specified number in an embodiment of the present application. Figure 9 A flow rate non-uniformity curve of the active section flow channel provided in the embodiments of this application.

[0019] In the diagram: 100, active section; 101, diversion section; 1011, spine; 102, confluence inlet; 103, confluence outlet; 104, mixing section. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] Terms that should be understood in this application: The high flow uniformity requirement region refers to the core region in the fuel cell electrode where the flow distribution uniformity needs to be strictly controlled, and it typically has the following characteristics: The active section in the middle: the main area where electrochemical reactions occur, and the flow deviation needs to be controlled within ±5%; the membrane electrode covered area: the area that directly participates in proton exchange, and uneven flow rate can lead to local overheating or reactant shortage; the straight section of the flow channel: the stable flow section far away from the inlet / outlet, and eddies or stagnation need to be avoided.

[0022] The core reaction zone with constant flow demand refers to the area where the fluid distribution within the active section has stabilized and no further diversion is required. This includes the following areas: located in the middle to rear section of the active section (≥60% of the channel length from the inlet); with a stable electrochemical reaction rate (current density fluctuation ≤±3%); and a pressure drop difference between channels <50Pa (verified by CFD simulation).

[0023] Directly connecting the overpass to the diversion area will cause the following technical problems: (1) The airflow entering from the overpass has a high velocity and a concentrated direction. If it directly impacts the diversion zone, it will cause: overload of the flow channel at the beginning of the diversion zone (increase the flow deviation); insufficient air supply at the end of the flow channel (reactant shortage); that is, uneven distribution caused by airflow impact, which is difficult to change through the structure of the subsequent diversion zone. (2) Pressure fluctuations caused by unstable flow state, unbuffered airflow is prone to eddies and pressure pulsations, affecting the consistency of electrochemical reaction.

[0024] (3) Water droplets carried by high-speed airflow are prone to collide and accumulate at the entrance of the diversion zone, causing local water blockage.

[0025] In addition, in the existing electrode flow field design, gas can exchange between adjacent flow channels in the split zone, and the flow path is not fixed. The flow rate of one active flow channel is often affected by multiple flow channels in the split zone. Therefore, when the flow rate of some active flow channels does not meet the requirements, it is not easy to modify, and it is easy to affect the flow rate of other channels. Moreover, it is often only the characteristics of some split zones near the active flow channel that are modified. The effect of such modification is not particularly good, and the direction of modification is relatively vague, so the effect of modification is not very good.

[0026] Therefore, this explanation will focus on the structure and design methods of fuel cell plates.

[0027] refer to Figure 1 and Figure 2 As shown, in a first aspect, a fuel cell electrode plate is provided, comprising: Active part 100; Convergence entrance 102; The confluence outlet 103 is diagonally arranged relative to the confluence inlet 102 with respect to the active part 100; both the confluence outlet 103 and the confluence inlet 102 are connected to a smooth-surfaced mixing part 104; the mixing part 104 is connected to the flow channel of the active part 100 through the diversion part 101. The surface of the shunt section 101 is provided with a plurality of ridges 1011 extending toward the active section 100. The ridges 1011 are protruding structures used to support the membrane electrode. A shunt channel is formed by the recess between adjacent ridges 1011.

[0028] The added smooth-surfaced mixing section 104 achieves uniform flow by expanding the volume and utilizing the fluid self-diffusion effect. It reduces the flow velocity through the channelless cavity structure and achieves self-uniform flow by utilizing fluid inertia, thereby reducing the velocity and allowing water droplets to settle and separate by gravity. In addition, different diversion channels are set according to different parts of the active section 100 to control the non-uniformity of the active section 100 within a reasonable fluctuation range.

[0029] In some preferred embodiments, the width of a single channel is less than or equal to 5 times the width of the spine 1011 and greater than or equal to 0.5 times the width of the spine 1011. This is because the channel width generally cannot be less than half the width of the spine, otherwise it is easy to clog, nor can it be greater than 5 times the width of the spine, otherwise the area will not provide sufficient support for the membrane electrode.

[0030] In some preferred embodiments, reference Figure 2 As shown, multiple spines 1011 form a primary flow channel, a secondary flow channel, a tertiary flow channel, and a quaternary flow channel; The primary flow channel has one inlet flow channel and one outlet flow channel; the secondary flow channel has one inlet flow channel and two outlet flow channels; the tertiary flow channel has one inlet flow channel and three outlet flow channels; and the quaternary flow channel has one inlet flow channel and four outlet flow channels. The primary diversion channel is connected to the core reaction zone of the active part 100 where the flow demand is constant; the secondary diversion channel is connected to the region of the active part 100 where the flow uniformity requirement is high; the tertiary and quaternary diversion channels are connected to the edge region of the electrode plate of the active part 100.

[0031] The active part 100 can also be called the active part. The reason for the above design of four flow distribution forms is as follows: The flow distribution is related to different parts of the active section. The two-stage flow distribution channel is suitable for areas with high flow uniformity requirements, such as the middle part of the active section. It has fewer branches, less influence from fluid inertia, and is easier to control flow deviation.

[0032] Three-stage and four-stage split channels are suitable for applications such as the edge of an electrode plate. By increasing the number of branches, the number of split stages can be reduced, but it is necessary to use a decreasing inlet width to suppress flow accumulation at the end.

[0033] The primary flow channel is used in areas with constant flow demand, simplifying the structure.

[0034] Due to the influence of fluid dynamic constraints, the inlet width needs to be significantly reduced after four levels of flow branching, resulting in a sharp increase in pressure loss; the flow deviation in the end flow channel also increases. When the channel spacing is less than 0.5 times the ridge width, the risk of water blockage increases.

[0035] Furthermore, in all primary flow channels, some primary flow channels are directly connected to the mixing section 104 and the active section 100, while the remaining sections are connected to secondary flow channels; In all the secondary diversion channels, the outlets of some secondary diversion channels are directly connected to the active part 100, while the rest are connected to the tertiary diversion channels; the tertiary diversion channels are connected to the quaternary diversion channels, and the quaternary diversion channels are connected to the active part 100.

[0036] This form represents a continuous connection, but it can also be a discontinuous connection, for example: In all primary flow channels, some primary flow channels are directly connected to the mixing section 104 and the active section 100, while the remaining parts are connected to the tertiary or quaternary flow channels.

[0037] That is, when the outline of the diversion zone is irregular, it can be connected in a skip-style manner, such as first-level diversion → third-level diversion, in conjunction with the curved flow channel to bypass it.

[0038] In this design, the inlet channel width of the secondary branch channel is d1, and the widths of the two branch channels are d3 and d4, respectively, where d1 = (1-1.1)×d4, d2 = (1-1.1)×d4, d3 = d4, and the angle α between d1 and d3 is greater than 150°; d2 is the first connecting transition channel at the junction of the branch channel d4 and the inlet channel, as shown in the reference diagram. Figure 3 As shown; if the number of active zone channels corresponding to d3 and d4 is the same, then the widths of d3 and d4 are the same. If it is a fourth-stage split, then the widths of d3 and d4 are the widths of the active zone channels. The inlet channel width of the three-stage branch flow channel is d1, and the widths of the three branch channels are d3, d4, and d5, respectively, where d1 = (1.4-1.6)×d5, d2 = (1.1-1.15)×d5, d6 = (1-1.1)×d5, d3 = d4 = d5, and the angle α between d1 and d3 is greater than 150°; d6 is the second connecting transition channel between the d5 branch channel and the first connecting transition channel; if the number of active zone channels corresponding to d6, d3, and d4 is the same, then the widths of d3, d4, and d5 are the same; if it is a fourth-stage branch flow channel, then the widths of d3, d4, and d5 are the active zone channel widths; Reference Figure 4 As shown; The inlet channel width of the four-stage branch flow channel is d1, and the widths of the four branch channels are d3, d4, d5, and d7, respectively. Where d1 = (1.7-1.8) × d7, d2 = (1.2-1.3) × d7, d6 = (1-1.1) × d7, and d8 = (0.6-0.7) × d7, d3 = d4 = d5 = d7, and the angle α between d1 and d3 is greater than 150°. d8 is the third connecting transition channel between the d7 branch channel and the second connecting transition channel. If the number of active zone channels corresponding to d3, d6, and d8 is the same, then the widths of d3, d4, d5, and d7 are the same. If it is a fourth-stage branch flow, then the widths of d3, d4, d5, and d7 are the active zone channel widths. Figure 5 As shown; CFD simulations verified that if α ≤ 150°, the fluid will deflect towards the terminal branch due to inertia. The minimum radius of curvature R1 of the four-stage split flow channel is ≥ 0.3 mm to prevent stress cracking. Secondly, this application provides a method for designing fuel cell electrode plates, comprising: Step 100: Obtain the width of the shunt channel in shunt section 101, establish the fuel cell electrode model, and then number the first-stage, second-stage, third-stage, and fourth-stage shunt channels according to their levels. The specific steps for numbering the first-stage, second-stage, third-stage, and fourth-stage shunt channels according to their levels are as follows: The first-level branch flow channel is labeled 1-a, the second-level branch flow channel is labeled 2-ab, the third-level branch flow channel is labeled 3-abc, and the fourth-level branch flow channel is labeled 4-abcd, where a, b, c, and d are the flow channel numbers of the corresponding levels. If a certain level of branch flow does not exist, the corresponding number is set to zero. The labeling can be referenced. Figure 6 and Figure 7 As shown.

[0039] Step 200: Calculate the theoretical flow rate corresponding to each level of the branch flow channel based on the number of flow channels and flow distribution requirements of the active part 100, and with reference to the hierarchical number. Step 300: Conduct fluid simulation experiments on the established fuel cell plate model to obtain the actual flow distribution of each branch channel; Step 400: Adjust the flow distribution of each branch channel based on the actual flow rate and the corresponding theoretical flow rate, and then repeat the simulation experiment until the flow rate non-uniformity of the active part 100 is less than the first design value, and the flow rate of the channels with the number of edge targets is greater than the second design value. Specifically, the adjustment involves adjusting the width of the branch channel, the angle between the branch channel and the corresponding main channel, and the radius of curvature between the branch channel and the corresponding main channel to address the flow rate deviation between the actual flow rate distribution and the corresponding theoretical flow rate of each branch channel.

[0040] In the above, the width of the flow channel is calculated based on the number of flow channels in the active part 100 corresponding to the branch flow channel in the secondary, tertiary, and quaternary branch flow channels. For example, the number of flow channels in the active section is N, the outlet width of the mixing section is D1, and the total flow rate at the outlet of the mixing section is Q.

[0041] Ideally, the flow rate of each active section should be the same. Of course, for some cases where there are special requirements for the flow rate of certain channels, calculations can also be performed, but here we are illustrating the calculation process by assuming that all channels have the same flow rate.

[0042] The primary diversion area connected to the mixing section outlet can be divided into two parts: the spine area and the flow passage area. The total width D2 of the spine area can be designed appropriately, and the total width D3 of the flow passage area is D1 = D2 + D3.

[0043] For any channel in the primary diversion flow zone, if the number of active flow channels that eventually flow into it is n, then its channel width is n / N*D3.

[0044] Similarly, the initial design of each width level is also adjusted based on its own width and the width of the active part.

[0045] If special design is required for the flow rate of certain channels, it can be multiplied by a coefficient α, but this coefficient is generally between 1 and 1.1, and it is not recommended to exceed 1.15, otherwise it may easily damage the membrane electrode.

[0046] The calculation of the width of the branch channel also includes the following steps: In the secondary, tertiary, and quaternary branch flow channels, if the number of flow channels in the active part 100 corresponding to the branch flow channels is the same, then the width of the branch flow channels is the same. In a four-stage branch flow channel, the width of each branch flow channel is the same.

[0047] If there is a flow channel in each branch flow channel where the number of active parts 100 is less than that of other branch flow channels, then the width of that flow channel is 70%-80% of the width of the other branch flow channels.

[0048] The above steps are used to obtain the widths of different flow channels; then, the following steps are performed during modeling: (1) After the design of the flow distribution zone is completed, fluid tests or simulations are performed to calculate the flow rate of each channel. To facilitate adjustment, each channel in the active part is first numbered (1, 2, 3, ..., n), and then each channel in the flow distribution zone is numbered according to the following rules: For the fourth-level diversion zone Level 1: Each flow channel is numbered 1-a, where 1 is the level 1 branch and a is the sequence number of the level 1 branch flow channel; Secondary (optional): Each flow channel is numbered 2-ab, where 2 represents the secondary branch, a is the sequence number of the primary branch flow channel, and b is the sequence number of the secondary branch flow channel under flow channel a. Level 3 (optional): Each flow channel is numbered 3-abc, where 3 represents the level 3 branch, a represents the sequence number of the level 1 branch flow channel, b represents the sequence number of the level 2 branch flow channel under flow channel a, and c represents the sequence number of the level 3 branch flow channel under flow channel b. If there is no level 2 branch, b is 0. Level 4: Each flow channel is numbered 4-abcd, where 4 represents the fourth-level flow branch, a is the sequence number of the first-level flow branch channel, b is the sequence number of the second-level flow branch channel under channel a, c is the sequence number of the third-level flow branch channel under channel c, and d is the sequence number of the fourth-level flow branch channel under channel c. If there are no second- or third-level flow branches, b and c are 0. (2) Then, based on the requirements of the diversion zone for each channel of the active part (common requirements include the non-uniformity of the active part channel within ±5, the flow rate of the 3-5 channels on both sides above 10%, or other special flow rate requirements), calculate the theoretical flow rate of each stage. (3) After numbering and calculation, experiments or simulations can be conducted to obtain the flow distribution results; (4)Calculate the actual flow rate of each level of flow channel based on the results, and then compare it with the theoretical flow rate in step (2), and all non-compliant structures can be traced quickly; reference Figure 8 Display of flow rate verification at each level (5)Then adjust the structural parameters of the flow splitting structures at each level (d2, R1 in the secondary flow splitting channel, d2, d6, R1 in the tertiary flow splitting channel, d2, d6, d8, R1 in the one-in-four splitting). Some common flow rate unevenness situations and adjustment methods are as follows: a.1 In the secondary flow splitting channel structure, when the flow rate of d3 is greater than d4 by n%, d2 can be reduced by n%; or by reducing R1 and increasing R2 by 2n%; or by reducing the α angle by 0.5n%. However, the method of adjusting the α angle has a greater impact on the structure of the flow splitting area and is generally not used. When α is too small, or d2 is too large, or R1 is too small, the fluid will tend to flow into d4 more.

[0049] a.2 In the secondary flow splitting channel structure, when the flow rate of d3 is less than d4 by n%, d2 can be increased by n%; or by increasing R1 and reducing R2 by 2n%; or by increasing the α angle by 0.5n%. However, the method of adjusting the α angle has a greater impact on the structure of the flow splitting area and is generally not used.

[0050] b.1 In the tertiary flow splitting channel structure, when the flow rates of the three branches are d3 < d4 < d5, with a ratio of n%, d2 can be reduced by n%, d6 can be reduced by 1.5n%. At the same time, it should be noted that d6 cannot be too small, otherwise the pressure loss will be too large. When the reduction ratio is greater than 25%, d5 can be reduced by 0.8n%; or by increasing R1 and reducing R2 by 2n%; or by increasing the α angle by n / 2%. However, the method of adjusting the α angle has a greater impact on the structure of the flow splitting area and is generally not used. When α is too small, or d2, d6 are too large, or R1 is too small, the fluid will tend to flow into d5 more.

[0051] b.2 In the tertiary flow splitting channel structure, when the flow rates of the three branches are d3 > d4 = d5, with a ratio of n%, d2 and d6 can be increased by n%; or by increasing R1 and reducing R2 by 2n%; or by increasing the α angle by n / 2%. However, the method of adjusting the α angle has a greater impact on the structure of the flow splitting area and is generally not used.

[0052] b.3 In the tertiary flow splitting channel structure, when the flow rates of the three branches are d3 < d4 = d5, with a ratio of n%, d2 and d6 can be increased by n%; or by increasing R1 and reducing R2 by 2n%; or by increasing the α angle by n / 2%. However, the method of adjusting the α angle has a greater impact on the structure of the flow splitting area and is generally not used.

[0053] b.4 In the three - stage split flow channel structure, when the flow rates of the three branch channels are d3 > d4, and d3 > d5 or d3 < d5, d3 is greater than d4m%, and d5 is greater than d4n%, d2 can be increased by m%, and d6 can be decreased by n%; or R1 and R2 can be decreased by m% and n% respectively.

[0054] c.1 In the four - stage split flow channel, when the flow rates of the four branch channels are d3 > d4 = d5 < d7, d3 is greater than or less than d7, d8 is greater than d46, d5m%, and d7 is greater than the n% of the flow rates of d4 and d5, d2 and d6 can be increased by m%, and d8 can be decreased by n%; or R1 and R2 can be decreased by m% and n% respectively.

[0055] c.2 In the four - stage split flow channel, when the flow rates of the four branch channels are d3 < d4 = d5 < d7, and the proportion is n%, d2 and d6 can be decreased by n%, and d8 can be decreased by 1.5n%. At the same time, it should be noted that d6 cannot be too small, otherwise the pressure loss will be too large. When the reduction ratio is greater than 25%, d7 can be decreased by 0.8n%; or R1 can be increased and R2 can be decreased by 2n%; or by increasing the α angle by n / 2%, but the method of adjusting the α angle has a greater impact on the split area structure and is generally not used.

[0056] When the number of branches ≥ 4, the fluid already has a strong tendency to flow from d1 through d2, d6, d8 and finally directly into d7. Therefore, the inlet width of the last flow channel is smaller than the width of the branch flow channels. So generally, the number of branches does not exceed 4, otherwise the inlet width will be too small, the pressure loss will be large, and it is easy to block water. When α is too small or d2, d6, d8 are too large or R1 is too small, the fluid will be more inclined to flow into d7.

[0057] (6) Repeat (1)-(5) until the result meets the requirements.

[0058] Through this method, the flow rate of the active part flow channel can be quickly controlled within a better range. The requirement for the active part is that the flow rates of the three flow channels on both sides are more than 10%, and the flow rate of the middle active part flow channel is within ±5%. The calculation method of the flow rate percentage a is:

[0059] is the flow rate of the nth flow channel in the active part, n = 1, 2, 3... is the total number of flow channels in the active part.

[0060] From Figure 9 it can be seen that the final version of the flow channel optimized by this method can achieve a very good effect and has a great improvement compared with the initial version.

[0061] The above steps enable rapid and effective iteration. By modifying only the dimensional parameters of some key features, a better flow distribution structure can be obtained. Each level of the flow channel affects the final flow rate of the active part. The hierarchical flow channel, combined with numbering and calculation, makes the direction of modification clearer and more specific. By modifying all flow channels that do not meet the requirements, the final design effect is better. This design method allows for flexible design of the flow distribution zone according to the user's requirements for the flow rate of the active part.

[0062] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and 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, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0063] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0064] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A fuel cell electrode plate, characterized in that, It includes: Active part (100); Convergence entrance (102); The confluence outlet (103) is diagonally arranged relative to the confluence inlet (102) with respect to the active part (100); both the confluence outlet (103) and the confluence inlet (102) are connected to a smooth-surfaced mixing part (104); the mixing part (104) is connected to the flow channel of the active part (100) through the diversion part (101); The surface of the shunt section (101) is provided with a plurality of ridges (1011) extending toward the active section (100). The ridges (1011) are protruding structures used to support the membrane electrode. A shunt channel is formed by recesses between adjacent ridges (1011).

2. The fuel cell electrode plate as described in claim 1, characterized in that: The width of a single branch channel is less than or equal to 5 times the width of the spine (1011) and greater than or equal to 0.5 times the width of the spine (1011).

3. The fuel cell electrode plate as described in claim 1, characterized in that: The multiple ridges (1011) form a primary diversion channel, a secondary diversion channel, a tertiary diversion channel, and a quaternary diversion channel; The primary diversion channel has one inlet channel and one outlet channel; the secondary diversion channel has one inlet channel and two outlet channels; the tertiary diversion channel has one inlet channel and three outlet channels; and the quaternary diversion channel has one inlet channel and four outlet channels. The first-level diversion channel is connected to the core reaction zone of the active part (100) with a constant flow requirement; the second-level diversion channel is connected to the high flow uniformity requirement area of ​​the active part (100); the third-level diversion channel and the fourth-level diversion channel are connected to the edge area of ​​the electrode plate of the active part (100).

4. The fuel cell electrode plate as described in claim 3, characterized in that: In all primary flow channels, some of the primary flow channels are directly connected to the mixing section (104) and the active section (100), while the remaining parts are connected to the secondary flow channels; In all secondary flow channels, the outlet of some secondary flow channels is directly connected to the active part (100), and the rest are connected to the tertiary flow channel; the tertiary flow channel is connected to the quaternary flow channel, and the quaternary flow channel is connected to the active part (100).

5. The fuel cell electrode plate as described in claim 3, characterized in that: In all primary flow channels, some of the primary flow channels are directly connected to the mixing section (104) and the active section (100), while the remaining parts are connected to the tertiary or quaternary flow channels.

6. The fuel cell electrode plate as described in claim 3, characterized in that: The inlet channel of the secondary branch channel is d1, and the two branch channels are d3 and d4 respectively; wherein the width and included angle dimensions are configured as follows: d1=(1-1.1)×d4, d2=(1-1.1)×d4, d3=d4, and the included angle between d1 and d3 is >150°, and d2 is the first connecting transition channel at the junction of d4 and d1; The inlet channel of the three-stage branch channel is d1, and the three branch channels are d3, d4 and d5. The width and included angle dimensions are configured as follows: d1=(1.4-1.6)×d5, d2=(1.1-1.15)×d5, d6=(1-1.1)×d5, d3=d4=d5, and the included angle between d1 and d3 is greater than 150°. d6 is the second connecting transition channel at the junction of d5 and d2. The inlet channel of the four-stage branch flow channel is d1, and the four branch channels are d3, d4, d5 and d7. The width and included angle dimensions are configured as follows: d1=(1.7-1.8)×d7, d2=(1.2-1.3)×d7, d6=(1-1.1)×d7, d8=(0.6-0.7)×d7, d3=d4=d5=d7, and the included angle between d1 and d3 is greater than 150°. d8 is the third connecting transition channel at the junction of d7 and d6.

7. A method for designing fuel cell plates as described in claim 3, characterized in that, It includes: Obtain the width of the shunt channel of the shunt section (101), establish the fuel cell plate model, and then number the first-level shunt channel, second-level shunt channel, third-level shunt channel and fourth-level shunt channel according to the hierarchy. Based on the number of flow channels and flow distribution requirements of the active part (100), and referring to the hierarchical number, calculate the theoretical flow rate corresponding to each level of the branch flow channel; Fluid simulation experiments were conducted on the established fuel cell plate model to obtain the actual flow distribution of each branch channel. Adjustments are made based on the actual flow distribution and corresponding theoretical flow of each branch channel, and then the simulation experiment is repeated until the flow non-uniformity of the active part (100) is less than the first design value, and the flow of the channel with the number of edge targets is greater than the second design value.

8. The design method for fuel cell plates as described in claim 7, characterized in that, Adjustments are made based on the actual flow distribution and corresponding theoretical flow of each branch channel, specifically including the following steps: The width of the branch channel, the angle between the branch channel and the corresponding main channel, and the radius of curvature between the branch channel and the corresponding main channel are adjusted according to the deviation between the actual flow distribution and the corresponding theoretical flow of each branch channel.

9. The design method for fuel cell plates as described in claim 7, characterized in that: In the secondary, tertiary, and quaternary branch channels, the corresponding channel width is calculated based on the number of channels in the active part (100) corresponding to the branch channel.

10. The design method for fuel cell plates as described in claim 9, characterized in that: The calculation of the width of the branch channel also includes the following steps: In the secondary, tertiary, and quaternary branch flow channels, if the number of flow channels in the active part (100) corresponding to the branch flow channel is the same, then the width of the branch flow channel is the same. In a four-stage branched flow channel, the width of each branch channel is the same; If there is a flow channel in each branch flow channel where the number of active parts (100) is less than that of other branch flow channels, then the width of that flow channel is 70%-80% of the width of the other branch flow channels.

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