Bipolar plate runner of proton exchange membrane fuel cell and hydrogen fuel cell

Abstract

The utility model provides a proton exchange membrane fuel cell bipolar plate runner and hydrogen fuel cell, including: a bipolar plate body, a plurality of runners extending along the same direction are formed on the bipolar plate body, the runners are non-linear runners of continuous circulation, and a plurality of throttling features are arranged in the runners. The non-linear flow channel is designed, the transverse mass transfer effect can be improved due to the existence of the transverse velocity component of the flow channel, and the flow velocity and pressure can be adjusted in the flow channel, turbulent flow is formed in the local part of the flow channel, and the under-ridge mass transfer capacity is enhanced due to the existence of the throttling characteristic.

Description

Technical Field

[0001] This utility model relates to the field of hydrogen fuel cells, specifically to a bipolar plate flow channel for a proton exchange membrane fuel cell and a hydrogen fuel cell. Background Technology

[0002] A proton exchange membrane hydrogen fuel cell (PEMFC) is a power generation device that uses hydrogen as fuel. Hydrogen undergoes an electrochemical reaction to produce water and generate electricity. The smallest unit in a fuel cell that completes the electrochemical reaction is called a single cell, which consists of an anode plate, a membrane electrode assembly (MEA), and a cathode plate. The bipolar plate, composed of the anode and cathode plates, is a core component of the fuel cell, serving to support the MEA, provide channels for reactant gases and coolant, and conduct charge and heat. Common bipolar plates are composed of one anode plate and one cathode plate joined together. The outer side of the anode plate has a hydrogen flow field, and the outer side of the cathode plate has an air flow field. A coolant flow field is formed inside the two plates. The outer flow field regions of the anode and cathode correspond to the active regions on the MEA and are crucial areas for the electrochemical reaction. The design of the flow channels determines the flow state of the reactant gases within these flow fields. A well-designed flow channel ensures the normal progress of the electrochemical reaction, improves the mass transfer efficiency of the reactants, and promptly removes the water product from the flow field, thereby enhancing the performance of the fuel cell. Currently, the most common flow channels are parallel flow channels, including straight-through channels, serpentine channels, and S-shaped channels.

[0003] However, while straight-through flow channels are simple in structure and easy to manufacture, with short flow channel lengths and low flow resistance and pressure drop, the residence time of reactant gases in the straight-through channel is short, resulting in low gas utilization. At the same time, the airflow in the channel is mostly laminar, lacking longitudinal gas exchange, which is not conducive to the transfer of reactant gases to the diffusion layer. On the other hand, the common S-shaped structure can improve gas mass transfer efficiency, but it will create greater flow resistance and pressure drop, which is not conducive to the discharge of liquid water. It also requires matching with a higher pressure ratio air compressor, resulting in power loss. Utility Model Content

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a bipolar plate flow channel for a proton exchange membrane fuel cell and a hydrogen fuel cell.

[0005] According to the present invention, a bipolar plate flow channel for a proton exchange membrane fuel cell includes: a bipolar plate body, wherein a plurality of flow channels extending in the same direction are formed on the bipolar plate body, the flow channels are continuous circulating non-linear flow channels, and a plurality of throttling features are provided in the flow channels.

[0006] Preferably, the flow channel is a continuously circulating S-shaped structure.

[0007] Preferably, the flow channel has a continuously circulating polygonal structure.

[0008] Preferably, the throttling feature is a smooth local boss or protrusion.

[0009] Preferably, the height of the throttling feature is 0-80% of the channel depth, and the height of the throttling feature increases with the increase of the liquid water content in the channel.

[0010] Preferably, in a polygonal flow channel, the throttling feature is arranged either at the inflection point of the polygon or at any position in the straight section of the polygon.

[0011] Preferably, the density of the throttling feature within the flow channel increases with the increase of the liquid water content within the flow channel.

[0012] Preferably, the throttling features are staggered in adjacent flow channels, and the arrangement includes:

[0013] Method 1: Arrange the throttling feature at the crest of one flow channel and the trough of the other flow channel;

[0014] Method 2: Along the direction of flow channel extension, arrange the throttling feature in the flow segment adjacent to the wave crest in one flow channel; and in the flow segment adjacent to the wave trough in another flow channel;

[0015] Method 3: Along the direction of the flow channel extension, the throttling feature is arranged at the crest and trough of one flow channel, and the flow section between the crest and trough of the other flow channel.

[0016] Preferably, the height of the throttling feature is a first height and a second height, and the first height is smaller than the second height;

[0017] For adjacent flow channels, the throttling feature in one flow channel adopts the first height, and the throttling feature in the other flow channel adopts the second height;

[0018] Alternatively, within a flow channel, two adjacent throttling features may employ a first height and a second height, respectively.

[0019] According to the present invention, a hydrogen fuel cell is provided, which adopts the above-mentioned proton exchange membrane fuel cell bipolar plate flow channel.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. This utility model designs a non-linear flow channel. Due to the presence of the transverse velocity component of the flow channel, the transverse mass transfer effect can be increased. Due to the existence of the throttling characteristic, the flow velocity and pressure can be adjusted in the flow channel, and turbulence can be formed locally in the flow channel to enhance the mass transfer capacity under the ridge.

[0022] 2. The height and density of the throttling feature in this invention are set according to the amount of liquid water in the flow channel, which is beneficial to the water management of the self-humidifying fuel cell.

[0023] 3. The throttling feature in this utility model adopts an alternating arrangement in adjacent flow channels, which generates velocity and pressure differences at the same position in adjacent flow channels, thereby enhancing the lateral mass transfer capacity between flow channels.

[0024] 4. The throttling feature in this utility model uses different heights in adjacent flow channels, which creates velocity and pressure differences at the same position in adjacent flow channels, thereby enhancing the lateral mass transfer capacity between flow channels. Attached Figure Description

[0025] Other features, objects and advantages of the present invention will become more apparent from the detailed description of the non-limiting embodiments with reference to the following drawings:

[0026] Figure 1 This is a top view of the throttling feature in this utility model arranged in configuration A;

[0027] Figure 2 This is a side view of the throttling feature in this utility model arranged in configuration A.

[0028] Figure 3 This is a partial schematic diagram of the throttling feature in this utility model, arranged in configuration A.

[0029] Figure 4 This is a top view of the throttling feature in this utility model, arranged in configuration B.

[0030] Figure 5 This is a side view of the throttling feature in this utility model arranged in the B configuration.

[0031] Figure 6 This is a partial schematic diagram of the throttling feature in this utility model, arranged in configuration B.

[0032] Figure 7 The top view shows the throttling feature of this utility model arranged in a C-shape.

[0033] Explanation of reference numerals in the attached figures:

[0034] Flow channel 1 throttling characteristic 2 Detailed Implementation

[0035] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0036] This utility model discloses a bipolar plate flow channel for a proton exchange membrane fuel cell. In the design of the bipolar plate flow channel, the flow channel 1 is arranged in a continuous S-shaped or zigzag pattern along the first direction (the direction of reactant gas flow, from the inlet end to the outlet end), such as... Figure 1 As shown. The dimensions of the S-curve or polygonal structure can be adjusted as needed. Due to the presence of the lateral velocity component in the S-curve or polygonal structure, the lateral mass transfer effect can be increased.

[0037] A throttling feature 2 is added inside the flow channel 1 to change the cross-section of the flow channel 1. Due to the presence of the throttling feature 2, the flow velocity and pressure can be adjusted in the flow channel 1, and turbulence can be formed locally in the flow channel 1 to enhance the mass transfer capacity under the ridge.

[0038] Throttling feature 2 is a smooth local protrusion or bump, which reduces the flow resistance generated by the local feature on the one hand, and generates gradient changes in velocity and pressure on the other hand for water management.

[0039] In the polygonal flow channel 1, the throttling feature 2 can be placed either near the inflection point of the polygon or at any position within the straight section of the polygon. In the S-shaped flow channel, the throttling feature 2 can be placed at any position in the flow channel 1.

[0040] The height of the throttling feature 2 is used as an adjustment parameter. Taking the protruding throttling feature 2 as an example, the lower limit of its protruding height is 0, that is, the feature completely disappears, and the upper limit of the protruding height is about 80% of the depth of the flow channel 1.

[0041] The size parameters of the throttling feature 2 can be adjusted according to the specific needs of water management: if more liquid water is generated in the flow channel 1, the height of the boss feature can be increased to enhance the variable cross-section feature of the flow channel 1; conversely, if less liquid water is generated in the flow channel 1, the height of the boss feature can be reduced to lower the flow resistance of this section, allowing the reactant gas to pass through quickly and reducing the amount of water carried away by the reactant gas, which is beneficial to the water management of the self-humidifying stack.

[0042] The density of the throttling feature 2 can be adjusted according to the specific needs of water management: if more liquid water is generated in the channel 1, the number of protrusion features can be increased, for example, multiple protrusion features can be arranged in a single straight segment; conversely, if less liquid water is generated in the channel 1, the number of protrusion features can be reduced, for example, the number of protrusion features in the same channel 1 can be halved, that is, only the protrusion features that were originally placed at intervals in the same channel 1 can be retained.

[0043] Throttling feature 2 can reduce the overall flow resistance of flow channel 1 by using a staggered arrangement, i.e., taking the polygonal flow channel 1 as an example:

[0044] (A) For every two adjacent flow channels 1, the throttling feature 2 is arranged at: 1) the crest of one flow channel, and 2) the trough of the other flow channel; refer to Figure 1-Figure 3 As shown.

[0045] (B) For every two adjacent flow channels 1, the throttling feature 2 is arranged in: 1) a straight line segment in the first positive direction adjacent to the crest of one flow channel, and 2) a straight line segment in the first positive direction adjacent to the trough of the other flow channel; (Refer to...) Figure 4-Figure 6 As shown.

[0046] (C) For every two adjacent flow channels 1, the throttling feature 2 is arranged at: 1) the crests and troughs of one flow channel, and 2) the straight segment of the other flow channel adjacent to the crests and troughs; refer to Figure 7 As shown.

[0047] By using the above arrangement, velocity and pressure differences are generated at the same locations in adjacent flow channels, thereby enhancing the lateral mass transfer capacity between flow channels.

[0048] The presence of the bosses reduces the cross-section of the flow channel. According to the Venturi effect and Bernoulli's principle, the gas velocity increases and the pressure decreases when passing through the bosses. The staggered arrangement creates a pressure difference at the throttling points of adjacent flow channels. This pressure difference forces the gas to be transferred laterally from the high-pressure area to the low-pressure area. The higher the boss height and the smaller the cross-section of the flow channel, the greater the pressure difference and the more obvious the mass transfer effect.

[0049] Based on the placement of the throttling feature 2, the height of the throttling feature 2 can be adjusted for every two adjacent flow channels 1. The height of the throttling feature 2 in one flow channel is uniformly set to the first height, and the height of the throttling feature 2 in the other flow channel is uniformly set to the second height.

[0050] Based on the above-mentioned placement of the throttling feature 2, the height of each pair of adjacent throttling features 2 in the same flow channel 1 can also be adjusted, with one throttling feature 2 having a first height and the other throttling feature 2 having a second height, and the two arranged at intervals.

[0051] In a preferred embodiment, the first height is smaller than the second height. The ratio of the throttling point height can be adjusted according to specific circumstances.

[0052] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0053] The specific embodiments of this utility model have been described above. It should be understood that this utility model is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the substantive content of this utility model. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A bipolar plate flow channel for a proton exchange membrane fuel cell, characterized in that, include: The bipolar plate body has several flow channels (1) extending in the same direction. The flow channels (1) are continuous circulating non-linear flow channels. Multiple throttling features (2) are provided in the flow channels (1). The throttling features (2) are staggered in adjacent channels (1), and the arrangement can be any of the following: Method 1: Arrange the throttling feature (2) at the crest of one flow channel (1) and at the trough of the other flow channel (1); Method 2: Along the direction of the flow channel (1), arrange the throttling feature (2) in the flow segment adjacent to the wave crest in one flow channel (1); and in the flow segment adjacent to the wave trough in another flow channel (1); Method 3: Along the direction of the flow channel (1), the throttling feature (2) is arranged at the crest and trough of one flow channel (1), and the flow segment between the crest and trough of the other flow channel (1); The height of the throttling feature (2) adopts a first height and a second height, and the first height is less than the second height; For adjacent flow channels (1), the throttling feature (2) in one flow channel (1) adopts the first height, and the throttling feature (2) in the other flow channel (1) adopts the second height; Alternatively, within a flow channel (1), two adjacent throttling features (2) may adopt a first height and a second height, respectively.

2. The proton exchange membrane fuel cell bipolar plate flow channel according to claim 1, characterized in that, The flow channel (1) is a continuously circulating S-shaped structure.

3. The proton exchange membrane fuel cell bipolar plate flow channel according to claim 1, characterized in that, The flow channel (1) is a continuously circulating polygonal structure.

4. The proton exchange membrane fuel cell bipolar plate flow channel according to claim 1, characterized in that, Throttling feature (2) is a smooth local protrusion or protrusion.

5. The proton exchange membrane fuel cell bipolar plate flow channel according to claim 4, characterized in that, The height of the throttling feature (2) is 0 to 80% of the depth of the channel (1), and the height of the throttling feature (2) increases with the increase of the liquid water content in the channel (1).

6. The proton exchange membrane fuel cell bipolar plate flow channel according to claim 3, characterized in that, In the broken-line flow channel (1), the throttling feature (2) is arranged at the turning point of the broken line, or at any position in the straight line segment of the broken line.

7. The proton exchange membrane fuel cell bipolar plate flow channel according to claim 5, characterized in that, The density of the throttling feature (2) set in the channel (1) increases with the increase of the liquid water content in the channel (1).

8. A hydrogen fuel cell, characterized in that, The proton exchange membrane fuel cell bipolar plate flow channel according to any one of claims 1-7 is adopted.

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