Bipolar plate of hydrogen fuel cell and hydrogen fuel cell

Abstract

The utility model relates to a bipolar plate of a hydrogen fuel cell and the hydrogen fuel cell, comprising a substrate on which a manifold region, a gap bridge region, a distribution region and an activation region are arranged; the activation area is used for catalyzing and reacting the gas; the activation area comprises a flow channel unit, the flow channel unit comprises a plurality of gas flow channels extending in the first direction, each gas flow channel comprises a straight area, a bent area, a first variable-diameter area and a second variable-diameter area which are sequentially arranged in the first direction, the first direction is the same as the length direction of the substrate, and the second direction is the same as the length direction of the substrate. The straight areas of every two adjacent gas flow channels are parallel to each other, and the bending directions of the bending areas of every two adjacent gas flow channels are parallel to each other. The bipolar plate disclosed by the utility model can improve the performance of the electric pile, and the electric pile adopting the variable-flow channel is higher in power for the electric pile with the same number of pieces. Moreover, the bipolar plate can reduce in-plane power generation deviation, so that electrochemical reaction is more uniform, the consistency of an electric pile is better, and the service life is effectively prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of hydrogen fuel cells, in particular to a bipolar plate of a hydrogen fuel cell and a hydrogen fuel cell. Background Art

[0002] There are many types of fuel cells, including solid oxide fuel cells, phosphoric acid fuel cells, alkaline fuel cells, direct methanol fuel cells, and proton exchange membrane fuel cells. Proton exchange membrane fuel cells have been widely used in recent years in automobiles, drones, power plants, and other fields. The hydrogen fuel cell stack is the core component of the fuel cell system, converting the chemical energy of hydrogen into electrical energy.

[0003] The flow channel structure of the active area of ​​the bipolar plate is varied, including serpentine flow channel (left), straight flow channel (right), meandering flow channel (center), etc. The flow channel structure diagram is as follows Figure 2 Conventional flow channel structures have some drawbacks, such as poor gas diffusion in the flow channel, poor gas diffusion along the back of the bipolar plate, poor drainage along the back, low pressure drop in straight channels, and high pressure drop in serpentine channels. The flow channel structure significantly impacts the performance and service life of the fuel cell stack. Utility Model Content

[0004] To this end, the technical problem to be solved by the present invention is to overcome the deficiencies in the existing technology and provide a hydrogen fuel bipolar plate. In response to the problems of slow mass transfer, poor drainage, and in-plane power generation deviation in the flow channels of traditional bipolar plates, the present invention can reduce the in-plane power generation deviation of the bipolar plate, making the electrochemical reaction more uniform and the stack more consistent, thereby effectively improving the service life.

[0005] To solve the above technical problems, the present invention provides a bipolar plate for a hydrogen fuel cell, comprising a substrate on which a manifold area, a bridge area, a distribution area, and an activation area are provided; a fluid enters or flows out of the bipolar plate through the manifold area; the bridge area is used to connect the manifold area and the distribution area to allow gas to flow between the manifold area and the distribution area; the distribution area is used to distribute the gas; and the activation area is used for catalysis and reaction of the gas;

[0006] The activation area includes a flow channel unit, which includes a plurality of gas flow channels extending along a first direction, each of the gas flow channels including a straight area, a bending area, a first diameter-changing area and a second diameter-changing area sequentially arranged along the first direction, the first direction is in the same direction as the length direction of the substrate, the straight areas of two adjacent gas flow channels are parallel to each other, the bending directions of the bending areas of two adjacent gas flow channels are parallel to each other, the bending area includes at least one bending portion, and the bending portion is bent toward the second direction, the cross-sectional diameter of the first diameter-changing area is periodically expanded and contracted, the cross-sectional diameter of the second diameter-changing area is periodically expanded and contracted, the expansion position and the contraction position of the two adjacent gas flow channels are opposite along the second direction, and the second direction is perpendicular to the first direction.

[0007] In one embodiment of the present invention, the activation area is provided with a ridge unit, the ridge unit includes at least one ridge component, the ridge component includes a first ridge and a second ridge extending along a first direction, the first ridge and the second ridge are spaced apart, and the gap between the first ridge and the second ridge forms the gas flow channel.

[0008] In one embodiment of the present invention, the first ridge includes a straight ridge, the second ridge includes a bent ridge, and the gap between the straight ridge and the bent ridge forms the first variable diameter area and the second variable diameter area; the thickness of the straight ridge is consistent, and the thickness of the bent ridge is consistent.

[0009] In one embodiment of the present invention, along the second direction, the bending amplitude of the bending ridge is 0.2-1.2 mm.

[0010] In one embodiment of the present invention, along the first direction, the swing period of the bending ridge gradually decreases.

[0011] In one embodiment of the present invention, the bending angle of the bending portion is 100-180°.

[0012] In one embodiment of the present invention, along a direction perpendicular to the substrate, the sum of the widths of the cross sections of two adjacent gas flow channels remains consistent.

[0013] In one embodiment of the present invention, the minimum width of the gas flow channel is a, 0.1mm<a<0.6mm, and the maximum width of the gas flow channel is b, 0.6mm<b<1.5mm.

[0014] In one embodiment of the present invention, the flow channel unit includes a first flow channel, a second flow channel, and a third flow channel that are sequentially spaced apart along the second direction, and the first flow channel and the third flow channel have the same shape and size.

[0015] The present invention also provides a hydrogen fuel cell, comprising a fuel cell stack, wherein the fuel cell stack comprises an end plate, an insulating member, a current collecting member, a fastener, a sealing member, a membrane electrode, and a bipolar plate of the hydrogen fuel cell as described above.

[0016] The above technical solution of the utility model has the following advantages compared with the prior art:

[0017] The bipolar plate of a hydrogen fuel cell described in the present invention includes a substrate and a manifold area, a bridge area, a distribution area and an activation area arranged on the substrate. The activation area includes a flow channel unit, and the flow channel unit includes a plurality of gas flow channels extending along a first direction. Each gas flow channel includes a straight area, a bending area, a first diameter-changing area and a second diameter-changing area arranged in sequence along the first direction; the cross-sectional diameter of the first diameter-changing area along the second direction expands and contracts periodically, and the cross-sectional diameter of the second diameter-changing area along the second direction expands and contracts periodically. The second direction is perpendicular to the first direction. The bipolar plate of the present invention can play a throttling role. , which promotes the diffusion of gas in the flow channel into the gas diffusion layer; the variable diameter flow channels in the first and second variable diameter regions can enhance the gas diffusion efficiency of adjacent flow channels, thereby intensifying the gas diffusion at the back of the bipolar plate, thereby enhancing the electrochemical reaction; and the variable diameter flow channels can enhance the drainage of water from the back of the bipolar plate, and also accelerate the drainage of water in the flow channels, thereby effectively reducing the probability of water flooding of the membrane electrode; compared with the bipolar plate structure in the prior art that only includes winding flow channels, straight flow channels, and serpentine flow channels, the bipolar plate of the present invention can improve the performance of the battery stack. For a battery stack with the same number of plates, the battery stack using the variable diameter flow channel has higher power. In addition, the bipolar plate of the present invention can reduce the in-plane power generation deviation, making the electrochemical reaction more uniform and the battery stack more consistent, thereby effectively improving the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings, wherein.

[0019] Figure 1 It is a schematic diagram of the fuel cell stack structure.

[0020] Figure 2 It is a schematic diagram of the flow channel structure in the prior art.

[0021] Figure 3 It is a schematic diagram of the overall structure of the bipolar plate in the prior art.

[0022] Figure 4 It is a schematic structural diagram of the activation zone of the bipolar plate in the preferred embodiment of the present invention.

[0023] Figure 5 yes Figure 4 Schematic diagram of gas flow.

[0024] Figure 6 yes Figure 4 Schematic diagram of the local structure.

[0025] Figure 7 It is a schematic diagram of gas flow in the flow channel cross section.

[0026] Explanation of the reference numerals in the specification: 1. Substrate; 2. Manifold area; 3. Bridge area; 4. Distribution area; 5. Activation area; 51. Straight area; 510. First arrow; 52. Bending area; 520. Second arrow; 521. Bending angle; 53. First diameter-changing area; 530. Third arrow; 54. Second diameter-changing area; 60. Catalytic layer; 61. GDL gas diffusion layer; 62. Wider part; 63. Narrower part; 64. Wider part; 7. Ridge assembly; 71. First ridge; 72. Second ridge; 81. First flow channel; 82. Second flow channel; 83. Third flow channel. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0028] The structural diagram of the battery stack is as follows Figure 1 As shown, the fuel cell stack primarily consists of end plates, insulating plates, current collectors, fasteners, seals, bipolar plates, and membrane electrodes. The bipolar plates and membrane electrodes are the core components of the fuel cell stack. The core of a fuel cell stack is formed by stacking multiple bipolar plates and membrane electrodes. The bipolar plates consist of cathode plates and anode plates, with oxygen flowing through the cathode plates and hydrogen flowing through the anode plates. A cooling water chamber is located between the cathode and anode plates. The bipolar plates provide rigid support for the core, separate the hydrogen, air, and water chambers, and ensure uniform distribution of fluid within each chamber, as well as electrical conductivity. Sealing strips are placed on both sides of the bipolar plates, which are compressed against the membrane electrode frame to achieve a seal. The membrane electrode is where the electrochemical reaction occurs and consists of a cathode and anode gas diffusion layer, a cathode and anode catalyst layer, and a proton exchange membrane. Example 1

[0029] Reference Figure 3 As shown, the present invention discloses a bipolar plate for a hydrogen fuel cell, comprising a substrate 1 , on which a manifold area 2 , a bridge area 3 , a distribution area 4 and an activation area 5 are provided.

[0030] The fluids in the three chambers enter or flow out of the bipolar plate through the manifold area 2, so that different fluids flow into the corresponding cavities respectively and are evenly distributed on each bipolar plate in the core. The manifold area 2 includes three manifold ports. The bridge area 3 is used to connect the manifold area 2 and the distribution area 4 to allow the gas to flow smoothly between the manifold area 2 and the distribution area 4. The distribution area 4 is used to evenly distribute the gas to ensure that the amount of gas in each flow channel is roughly equal. The activation area 5 is the reaction area of ​​the bipolar plate, where the gas can be catalyzed and reacted with the membrane electrode.

[0031] Specifically, refer to Figure 4 As shown, the activation zone 5 includes a flow channel unit, and the flow channel unit includes a plurality of gas flow channels extending along a first direction. Each of the gas flow channels includes a straight area 51, a bending area 52, a first variable diameter area 53 and a second variable diameter area 54 arranged in sequence along the first direction. The first direction is the same as the length direction of the substrate 1.

[0032] In detail, the straight areas 51 of two adjacent gas flow channels are parallel to each other;

[0033] The bending directions of the bending regions 52 of two adjacent gas flow channels are parallel to each other, and the bending region 52 includes at least one bending portion, and the bending portion bends toward the second direction;

[0034] The cross-sectional diameter of the first variable diameter region 53 along the second direction expands and contracts periodically;

[0035] The cross-sectional diameter of the second variable diameter region 54 along the second direction expands and contracts periodically;

[0036] The expansion position and the contraction position of two adjacent gas flow channels are opposite to each other along a second direction, and the second direction is perpendicular to the first direction.

[0037] Combine Figure 5 As shown, a schematic diagram of the flow and disturbance of gas in the flow channel unit is shown. The direction indicated by the arrow in the figure is the flow direction of the gas. The first arrow 510 indicates the flow direction of the gas in the straight area 51, the second arrow 520 indicates the direction of the gas disturbance in the bending area 52, and the third arrow 530 indicates the direction of the gas disturbance in the adjacent flow channel of the first variable diameter area 53. The gas disturbance intensity in the bending area 52 is relatively small, and the gas disturbance intensity in the first variable diameter area 53 is relatively large. The gas disturbance in the second variable diameter area 54 is stronger than the gas disturbance in the first variable diameter area 53. From the perspective of the entire flow field, from the straight area 51 to the second variable diameter area 54, the gas disturbance in the adjacent gas flow channels is gradually getting stronger.

[0038] From this, it can be known that the bipolar plate of a hydrogen fuel cell to be protected by the present invention comprises a substrate and a manifold area, a bridge area, a distribution area and an activation area arranged on the substrate, the activation area comprises a flow channel unit, the flow channel unit comprises a plurality of gas flow channels extending along a first direction, each gas flow channel comprises a straight area, a bending area, a first diameter-changing area and a second diameter-changing area arranged in sequence along the first direction; the cross-sectional diameter of the first diameter-changing area along the second direction expands and contracts periodically, the cross-sectional diameter of the second diameter-changing area along the second direction expands and contracts periodically, the second direction is perpendicular to the first direction, and the bipolar plate of the present invention can function The throttling effect promotes the diffusion of gas in the flow channel into the gas diffusion layer. The variable diameter flow channels in the first and second variable diameter regions can enhance the gas diffusion efficiency of adjacent flow channels, thereby intensifying the gas diffusion on the back of the bipolar plate, thereby enhancing the electrochemical reaction. Moreover, the variable diameter flow channels can enhance the drainage of water from the back of the bipolar plate, and also accelerate the drainage of water in the flow channels, thereby effectively reducing the probability of water flooding of the membrane electrode. Compared with the bipolar plate structure in the prior art that only includes winding flow channels, straight flow channels, and serpentine flow channels, the bipolar plate of the present invention can improve the performance of the battery stack. For battery stacks with the same number of plates, the battery stack using the variable diameter flow channel has higher power. In addition, the bipolar plate of the present invention can reduce the deviation of power generation within the surface, making the electrochemical reaction more uniform and the battery stack more consistent, thereby effectively improving the service life.

[0039] It should be noted that, combined with Figure 7 As shown, the gas flow in the flow channel cross section is schematically shown in the figure. In the first variable diameter region 53 and the second variable diameter region 54, the flow channel cross section becomes smaller, similar to a throttling point, causing a gas pressure difference between adjacent flow channels, thereby causing a strong gas movement in adjacent flow channels. 60 is a catalyst layer, 61 is a GDL gas diffusion layer, 62 and 64 are both wider parts of the gas flow channel, and 63 is a narrower part of the gas flow channel. The gas flow between adjacent flow channels is conducive to the diffusion of the back gas into the GDL of the membrane electrode. At the same time, the reaction water vapor generated by the cathode, before it accumulates too much, will be driven by this gas pressure difference and will be quickly blown out from the back of the bipolar plate into the flow channel. The pressure drop of the variable diameter flow field is relatively high, which can quickly discharge the water vapor in the flow channel out of the bipolar plate. This structure can not only improve the mass transfer of gas, but also accelerate the drainage in the flow field, reduce the probability of membrane electrode flooding, and thus improve the performance and service life of the stack.

[0040] Looking at the entire bipolar plate, after gas enters the plate, the gas concentration in the flow channel near the inlet is higher, while the gas concentration in the flow channel near the outlet is lower. Therefore, the gas needs to flow faster in the first half of the flow channel and slower in the second half to reduce the power generation deviation within the entire plate. Increasing the gas concentration in the second half of the flow channel increases the gas diffusion rate, which is more conducive to the reaction.

[0041] As a preferred embodiment, the activation area is provided with a ridge unit, and the ridge unit includes at least one ridge component 7, combined with Figure 6 As shown, the ridge assembly 7 includes a first ridge 71 and a second ridge 72 extending along a first direction. The first ridge 71 and the second ridge 72 are spaced apart, and the gap between the first ridge 71 and the second ridge 72 forms the gas flow channel.

[0042] Specifically, the first ridge 71 is configured as a straight ridge, the second ridge 72 is configured as a bent ridge, and the gap between the straight ridge and the bent ridge forms the first diameter-changing region 53 and the second diameter-changing region 54 .

[0043] As a preferred embodiment, the thickness of the straight ridge is consistent, and the thickness of the curved ridge is consistent. The thickness of the straight ridge and the curved ridge can be the same or different.

[0044] In detail, along the second direction, the bending amplitude AW of the bending ridge is 0.2-1.2 mm.

[0045] Specifically, along the first direction, the swing period of the bending ridge gradually decreases. Figure 7 As shown, the half swing period of the first diameter-varying region 53 is P1, the half swing period of the second diameter-varying region 54 is P2, and the length of P1 is greater than that of P2.

[0046] The sum P3 of two adjacent flow channel periods remains unchanged.

[0047] Of course, a plurality of half-oscillation period flow channels with intermediate values ​​between P1 and P2 can be set between P1 and P2.

[0048] As a preferred embodiment, refer to Figure 4 As shown, the bending angle 521 of the bending portion ranges from 100° to 180°.

[0049] Along the second direction, the sum of the widths of the cross sections of two adjacent gas flow channels remains consistent.

[0050] As a preferred embodiment, the minimum width of the gas flow channel is a, 0.1mm<a<0.6mm, and the maximum width of the gas flow channel is b, 0.6mm<b<1.5mm. In addition, the sum of the minimum width a and the maximum width b always remains consistent.

[0051] As a preferred embodiment, the flow channel unit includes a first flow channel 81, a second flow channel 82 and a third flow channel 83 that are sequentially spaced apart along the second direction, and the first flow channel 81 and the third flow channel 83 have the same shape and size. Example 2

[0052] A hydrogen fuel cell includes a stack, wherein the stack includes end plates, insulating members, current collectors, fasteners, seals, membrane electrodes, and a bipolar plate of a hydrogen fuel cell as described in Example 1.

[0053] In the description of the embodiments of the present invention, it should be noted that, unless otherwise specified or limited, the terms "disposed" and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0054] In the description of this utility model, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of this utility model, "plurality" means two or more, unless otherwise specifically defined.

[0055] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0056] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A bipolar plate for a hydrogen fuel cell, characterized in that: include, A substrate is provided with a manifold area, a bridge area, a distribution area, and an activation area; a fluid enters or flows out of the bipolar plate through the manifold area; the bridge area is used to connect the manifold area and the distribution area to allow gas to flow between the manifold area and the distribution area; the distribution area is used to distribute the gas; and the activation area is used for catalysis and reaction of the gas; The activation area includes a flow channel unit, which includes a plurality of gas flow channels extending along a first direction, each of the gas flow channels including a straight area, a bending area, a first diameter-changing area and a second diameter-changing area sequentially arranged along the first direction, the first direction is in the same direction as the length direction of the substrate, the straight areas of two adjacent gas flow channels are parallel to each other, the bending directions of the bending areas of two adjacent gas flow channels are parallel to each other, the bending area includes at least one bending portion, and the bending portion is bent toward the second direction, the cross-sectional diameter of the first diameter-changing area is periodically expanded and contracted, the cross-sectional diameter of the second diameter-changing area is periodically expanded and contracted, the expansion position and the contraction position of the two adjacent gas flow channels are opposite along the second direction, and the second direction is perpendicular to the first direction.

2. A bipolar plate for a hydrogen fuel cell according to claim 1, characterized in that: The activation area is provided with a ridge unit, the ridge unit includes at least one ridge component, the ridge component includes a first ridge and a second ridge extending along a first direction, the first ridge and the second ridge are spaced apart, and the gap between the first ridge and the second ridge forms the gas flow channel.

3. A bipolar plate for a hydrogen fuel cell according to claim 2, characterized in that: The first ridge includes a straight ridge, the second ridge includes a bent ridge, and a gap between the straight ridge and the bent ridge forms the first diameter-changing region and the second diameter-changing region; the straight ridge has a uniform thickness, and the bent ridge has a uniform thickness.

4. A bipolar plate for a hydrogen fuel cell according to claim 3, characterized in that: Along the second direction, the bending amplitude of the bending ridge is 0.2-1.2 mm.

5. A bipolar plate for a hydrogen fuel cell according to claim 3 or 4, characterized in that: Along the first direction, the swing period of the bending ridge gradually decreases.

6. The bipolar plate for a hydrogen fuel cell according to claim 1, characterized in that: The bending angle of the bending portion is 100-180°.

7. The bipolar plate for a hydrogen fuel cell according to claim 1, wherein: Along a direction perpendicular to the substrate, the sum of the widths of the cross sections of two adjacent gas flow channels remains consistent.

8. The bipolar plate for a hydrogen fuel cell according to claim 1, wherein: The minimum width of the gas flow channel is a, 0.1mm<a<0.6mm, and the maximum width of the gas flow channel is b, 0.6mm<b<1.5mm.

9. The bipolar plate for a hydrogen fuel cell according to claim 1, wherein: The flow channel unit includes a first flow channel, a second flow channel, and a third flow channel that are sequentially spaced apart along the second direction. The first flow channel and the third flow channel have the same shape and size.

10. A hydrogen fuel cell, characterized in that: The invention comprises a fuel cell stack, wherein the fuel cell stack comprises an end plate, an insulating member, a current collecting member, a fastener, a sealing member, a membrane electrode, and a bipolar plate of a hydrogen fuel cell as claimed in any one of claims 1 to 9.

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