Proton exchange membrane fuel cell bipolar plate fluctuating type combined flow channel and bipolar plate

Abstract

The utility model provides a proton exchange membrane fuel cell bipolar plate fluctuating type combined flow channel and bipolar plate, including bipolar plate, the flow channel of bipolar plate includes ridge and groove that are spaced apart, the groove is variable period fluctuating groove, the flow channel of bipolar plate is provided with a plurality of groups of circulation along the reaction gas flow direction, flow channel inlet side is the first circulation, flow channel inlet side is the second circulation, flow channel inlet side is the second circulation, and flow channel inlet side is the second circulation. The lengths of the multiple groups of cycles are gradually reduced from the first cycle in the reaction gas flowing direction, the period of the first cycle is a first period, and the period lengths of the multiple groups of cycles are gradually reduced from the first period in the reaction gas flowing direction. By adopting a combination of various runner characteristics, the cycle length can be adjusted, the flow resistance can be reduced, the reaction gas can quickly pass through according to the liquid water generation characteristics of the fuel cell, the water management of the self-humidifying galvanic pile is more facilitated, the flow velocity and pressure can be adjusted in the runner, the under-ridge mass transfer effect can be improved, and the better liquid water discharge effect can be achieved; therefore, the performance of the fuel cell is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of proton exchange membrane hydrogen fuel cell systems, in particular to an undulating combined flow channel and a bipolar plate of a proton exchange membrane fuel cell bipolar plate. Background Art

[0002] A proton exchange membrane hydrogen fuel cell is a power generation device that uses hydrogen as fuel. Hydrogen generates water and electricity through electrochemical reactions. The smallest component unit that completes the electrochemical reaction in a fuel cell is called a single cell, which is composed of an anode plate, a membrane electrode, and a cathode plate. The bipolar plate composed of the anode plate and the cathode plate is one of the core components of the fuel cell, which plays the role of supporting the membrane electrode, providing reaction gas and coolant flow channels, and conducting charge and heat. Common bipolar plates are spliced ​​by one anode plate and one cathode plate. The outside of the anode plate has a hydrogen flow field, the outside of the cathode plate has an air flow field, and the two plates form a coolant flow field. The outer flow field area of ​​the anode and cathode corresponds to the active area on the membrane electrode, which is an important area for generating electrochemical reactions. The design of the flow channel determines the flow state of the reaction gas in the flow field. Reasonable flow channel design can ensure that the electrochemical reaction can proceed normally and improve the mass transfer efficiency of the reactants. At the same time, the water of the reaction product is discharged from the flow field in time, thereby improving the performance of the fuel cell. At present, the most common flow channels are parallel flow channels, including straight flow channels, serpentine flow channels, S-shaped flow channels, etc.

[0003] The straight-through flow channel has a simple structure and is easy to process. The flow channel is short, and the flow resistance and pressure drop are small. However, the reaction gas has a short residence time in the straight flow channel and the gas utilization rate is low. At the same time, the air flow in the flow channel is mostly laminar, lacking longitudinal gas exchange, which is not conducive to the transfer of the reaction gas to the diffusion layer. Although the existing undulating flow channel bottom structure can improve the gas mass transfer efficiency, it will form a large flow resistance and pressure drop, which is not conducive to the discharge of liquid water. At the same time, it also requires a compressor with a higher pressure ratio, resulting in power loss.

[0004] Therefore, the inventors believe that it is necessary to optimize the traditional flow channel, increase the mass transfer effect under the ridge, and make it have a better liquid water discharge effect to prevent flooding and improve the performance of the fuel cell. Utility Model Content

[0005] In view of the defects in the prior art, the purpose of the utility model is to provide an undulating combined flow channel and a bipolar plate of a proton exchange membrane fuel cell bipolar plate.

[0006] According to the utility model, a proton exchange membrane fuel cell bipolar plate undulating combined flow channel includes a bipolar plate, the flow channel of the bipolar plate includes ridges and grooves arranged at intervals, the grooves are variable period undulating grooves, the bipolar plate flow channel is provided with multiple groups of cycles along the flow direction of the reaction gas, the inlet side of the flow channel is the first cycle, the lengths of the multiple groups of cycles gradually decrease from the first cycle along the flow direction of the reaction gas, the period of the first cycle is the first period, and the period lengths of the multiple groups of cycles gradually decrease from the first period along the flow direction of the reaction gas.

[0007] Preferably, the variable period undulating grooves include sawtooth undulating grooves, one undulation of which is a straight line segment and an S-shaped curve segment tangent thereto, and the straight line segment has an upward trend along the flow direction of the reaction gas.

[0008] Preferably, the bipolar plate flow channel is provided with a first cycle and a second cycle along the flow direction of the reaction gas, the flow channel inlet end of the bipolar plate flow channel is a straight line segment of the first cycle, the bottom end of the straight line segment is the deepest part of the groove, and after multiple cycles, it becomes a second cycle, and the cycle period changes from the first cycle to the second cycle, and the S-shaped curve segment of the first cycle is connected to the straight line segment of the second cycle.

[0009] Preferably, the length of the second period is 55%-60% of the length of the first period, the slope of the straight line segment of the first period is 8.8%, the depth of the bottom end of the straight line segment is 0.13 mm, and the S-shaped curve segment is two arcs of R0.2.

[0010] Preferably, the variable-period undulating groove is replaced by a fixed-period sawtooth undulating groove, and one cycle of the fixed-period sawtooth undulating groove is a straight line segment and an S-shaped curve segment tangent thereto, and the straight line segment shows an upward trend along the flow direction of the reaction gas. The single cycle length of the fixed-period sawtooth undulating groove is 1.6 mm, the bottom end depth of the straight line segment is 0.1 mm, and the S-shaped curve segment is two arcs of R0.2.

[0011] Preferably, the variable period undulating groove comprises a wavy undulating groove, with the reaction gas flow direction as the x-axis, the undulation amplitude y of the wavy undulating groove satisfies the function y=A·sin(Bx+C)+D, A, C, and D are all constants, and the cycle period of the undulating groove is It is also necessary to satisfy the curve function based on the Sigmoid function k, m, n, and q are all constants.

[0012] Preferably, the flow channel inlet end of the bipolar plate flow channel is not the highest point in the cycle, and the depth of the groove of the bipolar plate flow channel is 0.17 mm-0.23 mm.

[0013] Preferably, the ridges of the bipolar plate flow channel are ridges of equal height, equal width and arranged in parallel, the grooves of the bipolar plate flow channel are grooves of equal width, the width of the ridges of the bipolar plate flow channel is 0.2 mm, and the width of the grooves of the bipolar plate flow channel is 0.3 mm.

[0014] Preferably, the bipolar plate includes a metal bipolar plate, a graphite bipolar plate or a composite material bipolar plate.

[0015] According to a bipolar plate provided by the utility model, the above-mentioned undulating combined flow channel of the bipolar plate of the proton exchange membrane fuel cell is adopted.

[0016] Compared with the prior art, the utility model has the following beneficial effects:

[0017] 1. The present invention adopts a variable-period zigzag undulating flow channel, and the transition of the groove bottom on the inlet side is relatively smooth, which reduces the flow resistance of this section and allows the reaction gas to pass quickly, which is more conducive to the water management of the self-humidifying fuel cell stack. As the flow channel extends, the reaction gas flow rate decreases and the humidity increases, and liquid water is gradually generated and accumulated in the middle and rear sections of the flow channel. It is necessary to reduce the cycle period of the flow channel to make the variable cross-section feature of the flow channel more intense, so as to bring the liquid water in the membrane electrode out of the flow channel as soon as possible to prevent the fuel cell stack from being flooded. The variable-period zigzag flow channel feature can be used to adjust the cycle length according to the liquid water generation characteristics of the fuel cell, increase the mass transfer effect under the ridge, and make it have a better liquid water discharge effect to prevent flooding and improve the performance of the fuel cell.

[0018] 2. The present invention adopts a fixed-period undulating flow channel to adjust the characteristic parameters of the straight segment and the S-shaped curve according to the liquid water generation characteristics of the fuel cell. For example, if more liquid water is generated, the cycle period of the undulating feature can be appropriately reduced and the slope of the straight segment can be increased to make the variable cross-section feature of the flow channel more intense; conversely, if less liquid water is generated, the cycle period of the undulating feature can be increased, the slope of the straight segment can be reduced, and the length of the straight segment can be lengthened to reduce the flow resistance of the segment and allow the reaction gas to pass quickly; by using the cross-sectional change method of the undulating groove bottom, the flow velocity and pressure can be adjusted in the flow channel, a certain amount of turbulence can be formed locally, and the mass transfer capacity under the ridge can be enhanced. At the same time, the pressure drop caused by the continuous and large changes in the cross-section can be reduced to a certain extent, and the liquid water discharge effect can be better, thereby preventing flooding and improving the performance of the fuel cell.

[0019] 3. The present invention adopts a variable-period wavy undulating flow channel, which can optimize the variable-period parameter control curve in detail according to the liquid water generation characteristics of the fuel cell. The initial section has a slow change rate, presents an approximate constant function, and the flow channel undulation cycle period is approximately equal to the cycle period. The middle section has a rapid increase in the change rate, and the flow channel undulation cycle period decreases rapidly. The tail section has a gradual decrease in the change rate until it presents an approximate constant function again, and the flow channel cycle period is approximately equal to the cycle period. Such a design is conducive to the transition of design features, and at the same time prevents the outlet side flow channel cycle period from being too small, thereby increasing the reaction gas flow stability of the inlet and outlet sections. Due to the change of the cross-section in the flow direction, the flow velocity and pressure can be adjusted in the flow channel, the mass transfer effect under the ridge can be increased, and the liquid water discharge effect can be better, thereby preventing flooding and improving the performance of the fuel cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Other features, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0021] Figure 1 This is a schematic diagram of the undulating combined flow channel of the bipolar plate of the proton exchange membrane fuel cell in Example 1 of the present invention;

[0022] Figure 2 The present invention mainly embodies a top view of the undulating combined flow channel of the bipolar plate of the proton exchange membrane fuel cell in Example 1;

[0023] Figure 3 The present invention mainly embodies a side view of an undulating combined flow channel of a bipolar plate of a proton exchange membrane fuel cell in Example 1;

[0024] Figure 4 This is a schematic diagram of the undulating combined flow channels of the bipolar plate of a proton exchange membrane fuel cell in Example 2 of the present invention;

[0025] Figure 5 The present invention mainly embodies a top view of the undulating combined flow channel of the bipolar plate of the proton exchange membrane fuel cell in Example 2;

[0026] Figure 6 This is a side view of the undulating combined flow channel of the bipolar plate of the proton exchange membrane fuel cell in Example 2 of the present invention;

[0027] Figure 7 This is a schematic diagram of the undulating combined flow channels of the bipolar plate of a proton exchange membrane fuel cell in Example 3 of the present invention;

[0028] Figure 8 The present invention mainly embodies a side view of an undulating combined flow channel of a bipolar plate of a proton exchange membrane fuel cell in Example 3;

[0029] Fig. 9The present invention mainly embodies the parameter characteristics of the flow channel variable period in Example 3.

[0030] Reference numerals:

[0031] Ridge 1 Groove 2 DETAILED DESCRIPTION

[0032] The utility model is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the utility model, but do not limit the utility model in any form. It should be pointed out that for those of ordinary skill in the art, several changes and improvements can be made without departing from the concept of the utility model. These all belong to the protection scope of the utility model.

[0033] Example 1

[0034] like Figure 1-3 As shown, according to the utility model, a proton exchange membrane fuel cell bipolar plate undulating combined flow channel includes a bipolar plate, the flow channel of the bipolar plate includes ridges 1 and grooves 2 arranged at intervals, the groove 2 is a variable period undulating groove, the bipolar plate flow channel is provided with multiple groups of cycles along the flow direction of the reaction gas, the inlet side of the flow channel is the first cycle, the length of the multiple groups of cycles gradually decreases from the first cycle along the flow direction of the reaction gas, the period of the first cycle is the first period, and the period length of the multiple groups of cycles gradually decreases from the first period along the flow direction of the reaction gas.

[0035] The variable period undulating grooves include sawtooth undulating grooves, one undulation of which is a straight line segment and an S-shaped curve segment tangent thereto, and the straight line segment presents an upward trend along the flow direction of the reaction gas.

[0036] The flow channel of the bipolar plate is composed of ridges 1 and grooves 2. A concave groove is formed between two adjacent ridges 1, so that the reaction gas flows therein. The flow channel of the bipolar plate of the present application has a continuous cyclic zigzag undulation feature at the bottom of the groove along the reaction gas flow direction (i.e., from the inlet end to the outlet end). The bottom line of the zigzag flow channel in each cycle is composed of a straight line segment and an S-shaped curve tangent thereto.

[0037] This application is explained by taking the bipolar plate flow channel as an example in which the first cycle and the second cycle are arranged along the flow direction of the reaction gas. The flow channel inlet end of the bipolar plate flow channel is a straight line segment of the first cycle, and the bottom end of the straight line segment is the deepest part of the groove 2. After multiple cycles, it becomes the second cycle, and the cycle period changes from the first cycle to the second cycle. The S-shaped curve segment of the first cycle is connected to the straight line segment of the second cycle. In practical applications, different cycles are set to meet the requirements of the reaction gas flow rate at different positions of the flow channel.

[0038] Further, the following data is used as an example for explanation. The length of the second cycle is 55%-60% of the length of the first cycle. The slope of the straight segment of the first cycle is 8.8%, and the depth of the bottom end of the straight segment is 0.13mm. The S-shaped curve segment is two arcs of R0.2. The ridge 1 of the bipolar plate flow channel is a ridge of equal height, equal width and parallel arrangement, and the groove 2 of the bipolar plate flow channel is a groove of equal width. The width of the ridge 2 of the bipolar plate flow channel is 0.2mm, and the width of the groove 2 of the bipolar plate flow channel is 0.3mm. In practical applications, it can be adjusted as needed without limitation.

[0039] The bipolar plates include metal bipolar plates, graphite bipolar plates or composite bipolar plates.

[0040] In practical applications, multiple sets of different cycle periods can also be set, not limited to two sets of cycle periods. Similarly, the cycle variation can also be adjusted.

[0041] In this way, the flow rate and pressure can be adjusted in the flow channel, and a certain amount of turbulence can be formed locally to enhance the mass transfer capacity under the ridge. The transition of the bottom of the groove on the inlet side is relatively gentle (large cycle), because the water content on the cathode inlet side is less, and a strong variable cross-section feature is not required to discharge liquid water. At the same time, the flow resistance of this section is reduced (compared to the back section of the flow channel), which allows the reactant gas to pass quickly, which is more conducive to the water management of the self-humidifying stack.

[0042] As the flow channel extends, the reaction gas flow rate decreases and the humidity increases, and liquid water gradually generates and accumulates in the middle and rear sections of the flow channel. It is necessary to reduce the circulation period of the flow channel to make the variable cross-section characteristics of the flow channel more intense, so as to bring the liquid water in the membrane electrode out of the flow channel as soon as possible to prevent the battery stack from being flooded.

[0043] By adopting the variable-period serrated flow channel characteristics, the lengths of the first and second periods can be adjusted according to the liquid water generation characteristics of the fuel cell: if liquid water accumulates in large quantities on the outlet side of the rear section of the flow channel, the length of the second period can be further shortened to improve the drainage performance; conversely, if there is less liquid water on the outlet side of the rear section of the flow channel, the length of the second period can be increased until it is greater than the length of the first period while meeting actual needs.

[0044] The present application optimizes the traditional flow channel and uses the cross-sectional variation of the undulating groove bottom to increase the mass transfer effect under the ridge and provide a better liquid water discharge effect, thereby preventing flooding and improving the performance of the fuel cell.

[0045] Example 2

[0046] like Figure 4-6As shown, based on Example 1, the variable period undulating grooves are replaced by fixed period zigzag undulating grooves, and the flow channel of the bipolar plate includes ridges 1 and grooves 2 arranged at intervals, and groove 2 is a continuously cyclic zigzag undulating groove, and one cycle of the zigzag undulating groove is a straight line segment and an S-shaped curve segment tangent thereto, and the straight line segment shows an upward trend along the flow direction of the reaction gas.

[0047] The flow channel of the bipolar plate is composed of ridges 1 and grooves 2. A concave groove is formed between two adjacent ridges 1, so that the reaction gas flows therein. The bipolar plate flow channel of the present application has a continuous cyclic zigzag undulation feature at the bottom of the groove along the reaction gas flow direction (i.e., from the inlet end to the outlet end). The bottom line of the zigzag flow channel in each cycle is composed of a straight line segment and an S-shaped curve tangent to it. The flow channel inlet end of the bipolar plate flow channel is a straight line segment.

[0048] This application is explained by taking the following data as an example. The slope of the straight line segment is 7.5%. The bottom depth of the straight line segment is 0.1 mm. The S-shaped curve segment is formed by splicing two arcs of R0.2. The single cycle length of the zigzag undulating groove is 1.6 mm. The width of the ridge 1 of the bipolar plate flow channel is 0.2 mm. The width of the groove 2 of the bipolar plate flow channel is 0.3 mm. It can be adjusted according to actual needs without limitation.

[0049] The bipolar plates include metal bipolar plates, graphite bipolar plates or composite bipolar plates.

[0050] In the prior art, sine and cosine function curves are common bottom undulation curves, but because they are continuous waveform functions, under the premise of constant channel width, the corresponding channel cross-sectional area is constantly changing, resulting in an increase in the overall pressure drop of the system; and if large-period sine and cosine curves are used, the longitudinal mass transfer capacity will be greatly reduced. The flow channel of the present application can adjust the flow rate and pressure in the flow channel, form a certain amount of turbulence locally, enhance the mass transfer capacity under the ridge, and reduce the pressure drop caused by continuous and large changes in the cross section to a certain extent.

[0051] By adopting the undulating flow channel characteristics, the characteristic parameters of the straight segment and the S-shaped curve can be adjusted according to the liquid water generation characteristics of the fuel cell: if more liquid water is generated, the cycle period of the undulating characteristics can be appropriately reduced and the slope of the straight segment can be increased to make the variable cross-section characteristics of the flow channel more intense; conversely, if less liquid water is generated, the cycle period of the undulating characteristics can be increased, the slope of the straight segment can be reduced, and the length of the straight segment can be lengthened to reduce the flow resistance of the segment and allow the reaction gas to pass quickly.

[0052] The present application optimizes the traditional flow channel and uses the cross-sectional variation of the undulating groove bottom to increase the mass transfer effect under the ridge and provide a better liquid water discharge effect, thereby preventing flooding and improving the performance of the fuel cell.

[0053] Example 3

[0054] like Figure 7-9 As shown, based on Example 1, the flow channel of the bipolar plate includes ridges 1 and grooves 2 arranged at intervals, and the groove 2 is a variable period undulating groove, with the flow direction of the reaction gas as the x-axis and the vertical direction as the y-axis. The undulation amplitude y of the undulating groove satisfies the sine (or cosine) function y=A·sin(Bx+C)+D, A, C, and D are all constants, and the cycle period of the undulating groove is It is also necessary to satisfy the curve function based on the Sigmoid function k, m, n, and q are all constants.

[0055] The flow channel of the bipolar plate is composed of ridges 1 and grooves 2, and a concave groove is formed between two adjacent ridges 1, so that the reaction gas flows therein. The flow channel of the bipolar plate of the present application has a continuous cyclic undulation at the bottom of the groove along the reaction gas flow direction (i.e., from the inlet end to the outlet end), and the period is continuously variable according to the parameter characteristic curve.

[0056] The flow channel inlet end of the bipolar plate flow channel is not the highest point in the cycle.

[0057] This application is explained by taking the following data as an example: The depth of the groove 2 of the bipolar plate flow channel is 0.17 mm-0.23 mm. The width of the groove 2 of the bipolar plate flow channel is 0.3 mm. The width of the ridge 1 of the bipolar plate flow channel is 0.2 mm.

[0058] The bipolar plates include metal bipolar plates, graphite bipolar plates or composite bipolar plates.

[0059] Depend on Figure 8 It can be found that the transition at the bottom of the groove at the inlet of the flow channel is relatively smooth. Because the water content on the cathode inlet side is less, a strong variable cross-section feature is not needed to discharge liquid water. At the same time (compared to the rear section of the flow channel), the flow resistance of this part is reduced, allowing the reaction gas to pass quickly, which is more conducive to the water management of the self-humidifying fuel cell stack.

[0060] As the flow channel extends, the reaction gas flow rate decreases and the humidity increases, and liquid water gradually generates and gathers in the middle and rear sections of the flow channel. It is necessary to reduce the circulation period of the flow channel to make the variable cross-section characteristics more intense. The resulting frequency of speed and pressure changes along the flow direction becomes higher, so as to bring the liquid water in the membrane electrode out of the flow channel as quickly as possible to prevent the stack from being flooded.

[0061] By adopting the variable period undulating flow channel characteristics, the variable period parameter control curve can be optimized in detail according to the liquid water generation characteristics of the fuel cell. Fig. 9It is a nonlinear change curve of the parameter characteristics of the flow channel variable period, which is characterized by a slow change rate in the initial section, presenting an approximate constant function, and the flow channel fluctuation cycle period is approximately equal to the cycle period, a rapid increase in the middle section change rate, and a rapid decrease in the flow channel fluctuation cycle period, and a gradual decrease in the tail section change rate until it presents an approximate constant function again, and the flow channel cycle period is approximately equal to the cycle period again. Such a design is conducive to the transition of design features, while preventing the outlet side flow channel cycle period from being too small, and increasing the reaction gas flow stability of the inlet and outlet sections.

[0062] The flow channel variable period parameter curve can be adjusted according to specific needs, such as linear change and nonlinear change, different change slopes and different nonlinear change curves. For example, change the value range of k, m, n, q, increase or decrease the length of the low change rate interval of the inlet section and the outlet section, increase or decrease the amplitude of the cycle change of the middle section; or replace the above nonlinear change curve function B with a linear function, such as B = kx + t (k, t are constants).

[0063] The present application optimizes the traditional flow channel and uses a cross-sectional change method of a variable-period undulating groove bottom. Due to the change of the cross-section in the flow direction, the flow velocity and pressure can be adjusted in the flow channel, the mass transfer effect under the ridge can be increased, and the liquid water discharge effect can be better, thereby preventing flooding and improving the performance of the fuel cell.

[0064] Example 4

[0065] According to a bipolar plate provided by the present invention, the undulating combined flow channel of the proton exchange membrane fuel cell bipolar plate of any one of Examples 1-3 is adopted.

[0066] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0067] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other at will.

Claims

1. A undulating combined flow channel of a bipolar plate of a proton exchange membrane fuel cell, characterized in that: The invention comprises a bipolar plate, wherein the flow channel of the bipolar plate comprises ridges (1) and grooves (2) arranged at intervals, wherein the grooves (2) are variable period undulating grooves, and the bipolar plate flow channel is provided with a plurality of groups of cycles along the flow direction of the reaction gas, wherein the inlet side of the flow channel is a first cycle, wherein the lengths of the plurality of groups of cycles gradually decrease from the first cycle along the flow direction of the reaction gas, wherein the period of the first cycle is a first period, and the period lengths of the plurality of groups of cycles gradually decrease from the first period along the flow direction of the reaction gas.

2. The undulating combined flow channel of the bipolar plate of a proton exchange membrane fuel cell according to claim 1, characterized in that: The variable period undulating groove comprises a sawtooth undulating groove, wherein one undulation of the sawtooth undulating groove is a straight line segment and an S-shaped curve segment tangent thereto, and the straight line segment presents an upward trend along the flow direction of the reaction gas.

3. The undulating combined flow channel of the bipolar plate of a proton exchange membrane fuel cell according to claim 2, characterized in that: The bipolar plate flow channel is provided with a first cycle and a second cycle along the flow direction of the reaction gas, the flow channel inlet end of the bipolar plate flow channel is a straight line segment of the first cycle, the bottom end of the straight line segment is the deepest part of the groove (2), and after multiple cycles, it becomes a second cycle, the cycle period changes from the first cycle to the second cycle, and the S-shaped curve segment of the first cycle is connected to the straight line segment of the second cycle.

4. The undulating combined flow channel of the bipolar plate of a proton exchange membrane fuel cell according to claim 3, characterized in that: The length of the second period is 55%-60% of the length of the first period, the slope of the straight line segment of the first period is 8.8%, the depth of the bottom end of the straight line segment is 0.13mm, and the S-shaped curve segment is two arcs of R0.

2.

5. The undulating combined flow channel of the bipolar plate of a proton exchange membrane fuel cell according to claim 1, characterized in that: The variable period undulating groove is replaced by a fixed period sawtooth undulating groove, one cycle of which is a straight line segment and an S-shaped curve segment tangent thereto, and the straight line segment is rising along the flow direction of the reaction gas, a single period length of the fixed period sawtooth undulating groove is 1.6 mm, the bottom end depth of the straight line segment is 0.1 mm, and the S-shaped curve segment is two arcs of R0.

2.

6. The undulating combined flow channel of the bipolar plate of a proton exchange membrane fuel cell according to claim 1, characterized in that: The variable period undulating groove includes a wavy undulating groove, with the reaction gas flow direction as the x-axis, the undulation amplitude y of the wavy undulating groove satisfies the function y=A·sin(Bx+C)+D, A, C, and D are all constants, and the cycle period of the undulating groove is It is also necessary to satisfy the curve function based on the Sigmoid function k, m, n, and q are all constants.

7. The undulating combined flow channel of the bipolar plate of a proton exchange membrane fuel cell according to claim 6, characterized in that: The flow channel inlet end of the bipolar plate flow channel is not the highest point in the cycle, and the depth of the groove (2) of the bipolar plate flow channel is 0.17mm-0.23mm.

8. The undulating combined flow channel of the bipolar plate of a proton exchange membrane fuel cell according to claim 1, characterized in that: The ridges (1) of the bipolar plate flow channel are ridges of equal height and width and are arranged in parallel, the grooves (2) of the bipolar plate flow channel are grooves of equal width, the width of the ridges (1) of the bipolar plate flow channel is 0.2 mm, and the width of the grooves (2) of the bipolar plate flow channel is 0.3 mm.

9. The undulating combined flow channel of the bipolar plate of a proton exchange membrane fuel cell according to claim 1, characterized in that: The bipolar plate includes a metal bipolar plate, a graphite bipolar plate or a composite material bipolar plate.

10. A bipolar plate, characterized in that: The undulating combined flow channel of the bipolar plate of a proton exchange membrane fuel cell is adopted as described in any one of claims 1 to 9.

Images