A flow field plate for improving the performance of a fuel cell

Abstract

The application discloses a flow field plate for improving the performance of a fuel cell, comprising a flow field plate body, a baffle, a flow channel and a flow channel ridge; the flow channel is arranged in a serpentine structure on the flow field plate body, and comprises a plurality of straight sections and turning sections; the turning sections are connected to the end portions of adjacent straight sections, and the flow channel ridges are formed between the adjacent straight sections; the baffle is arranged close to the side wall of the turning section, so that a channel is formed between the baffle and the end portion of the flow channel ridge; or the baffle is arranged close to the end portion of the flow channel ridge, so that a channel is formed between the baffle and the side wall of the turning section. When the baffle is dry, the pressure drop in the flow channel is reduced, and the mass transfer efficiency of the gas is improved; when the baffle absorbs water, the water flooding phenomenon is effectively prevented, and the flow resistance of the gas is reduced; through the above automatic adjustment mechanism, the fuel cell can automatically optimize the performance under different working conditions, reduce energy loss and improve overall energy efficiency.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and more specifically to a flow field plate for improving fuel cell performance. Background Technology

[0002] Fuel cells, with their advantages of high energy conversion efficiency, environmental friendliness, low noise, flexibility, reliability, and continuous power supply, have demonstrated enormous development potential and broad application prospects in the energy field. The flow field plate, as an indispensable and crucial component for the normal and efficient operation of a fuel cell, primarily guides the flow direction of the reactant gases, ensuring their uniform distribution throughout the electrodes and their passage through the electrode diffusion layer to the catalyst layer to participate in the electrochemical reaction. The design of the flow field plate is critical for improving the utilization efficiency of the reactant gases, drainage, and heat dissipation performance of the fuel cell.

[0003] Traditional serpentine flow field plates are widely used due to their unique serpentine gas flow path. The meandering flow channels of the serpentine flow field plate effectively extend the contact path between the gas and the electrode, increase the transmission area, and promote the uniformity of gas distribution, thereby helping to improve the efficiency of electrochemical reactions. Despite these advantages, serpentine flow field plates also have some significant drawbacks, particularly in the flow channel turning regions, where the gas velocity decreases significantly, easily leading to the accumulation of liquid water and causing localized flooding. This flooding not only hinders effective gas diffusion but may also exacerbate drainage difficulties, thus affecting the overall performance of the fuel cell. Furthermore, the design of serpentine flow field plates is accompanied by higher flow resistance and pressure drop issues. When gas flows in the meandering channels, it must overcome multiple sharp turns and flow channel friction, leading to pressure drops and increased energy losses. Especially at flow field turning points, if a large amount of liquid water accumulates, it will further increase flow resistance, causing additional power consumption, ultimately reducing energy conversion efficiency and affecting the stability and lifespan of the fuel cell.

[0004] Therefore, in the design of fuel cell flow field plates, it is necessary to balance the advantages of uniform gas distribution brought by serpentine flow field plates with the accompanying problems such as flow resistance and local flooding. By optimizing the flow channel structure and improving the drainage strategy, the performance of fuel cells can be maximized. Summary of the Invention

[0005] The purpose of this invention is to provide a flow field plate with porous baffles, which utilizes the water absorption effect of the porous baffles to solve the problems of local flooding, flow resistance and pressure drop caused by traditional serpentine flow field plates, thereby improving the overall performance of fuel cells.

[0006] To achieve the above objectives, the present invention provides a flow field plate for improving the performance of fuel cells, comprising a flow field plate body, a baffle, a flow channel, and a flow channel ridge;

[0007] The flow channel is arranged in a serpentine structure on the flow field plate body. The flow channel includes several direct flow sections and turning sections. The turning sections connect the ends of adjacent direct flow sections, and the flow channel ridge is formed between adjacent direct flow sections.

[0008] The stop block is positioned at the turning section and is flush against the side wall of the turning section, forming a channel between the stop block and the end of the flow channel ridge; or

[0009] The stop block is located at the turning section and is close to the end of the flow channel ridge, so that a channel is formed between the stop block and the side wall of the turning section.

[0010] Optionally, the width of the stop block is smaller than the width of the turning section, and the width of the stop block is larger than the width of the flow channel ridge.

[0011] Optionally, the width of the stop block is 1mm-2mm, the width of the turning section is 1.5mm-2.5mm, and the width of the flow channel ridge is 0.5mm-1.5mm.

[0012] Optionally, the shape of the stop block can be any one of a rectangle, a concave shape, a triangle, or a semicircle.

[0013] Optionally, the material of the stop block is any one of water-absorbing resin, hydrogel, and natural fiber.

[0014] Optionally, the baffle has a porous structure, and the baffle shrinks when it absorbs water and recovers when it loses water.

[0015] Optionally, the stop is provided at each of the steering segments.

[0016] Optionally, it also includes an air inlet and an air outlet, which are respectively connected to the two ends of the flow channel. Gas flows into the flow channel from the air inlet and flows out of the flow channel from the air outlet.

[0017] Optionally, the width of the DC section is 1mm-2mm and the depth is 1mm-2mm; the depth of the deflection section is 1mm-2mm; the thickness of the flow channel ridge is 1mm-2mm; and the thickness of the baffle is 1mm-2mm.

[0018] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0019] 1) This invention incorporates a highly absorbent baffle in the flow channel turning section of the fuel cell flow field plate. When the current density is low and the water production rate is slow, the baffle, in its dry state, reduces the gas flow path at the turning section, accelerating the gas flow rate and improving mass transfer efficiency. Simultaneously, due to the baffle's porous structure and loose internal structure, gas can pass through it, reducing pressure drop and thus improving the overall performance of the fuel cell. Furthermore, when a large amount of liquid water accumulates in the flow channel turning section, the baffle absorbs the moisture and contracts due to its strong absorbent properties. This not only increases the gas flow path at the turning section, reducing the internal pressure drop and gas flow resistance, but also significantly reduces the obstruction of liquid water to gas transmission, effectively preventing flooding and ensuring stable operation of the fuel cell in high humidity environments. Additionally, during the purging phase after fuel cell shutdown, gas flows through the surface and interior of the baffle, carrying away moisture and restoring the baffle's volume.

[0020] 2) Furthermore, through the aforementioned automatic adjustment mechanism, fuel cells can automatically optimize their performance under different operating conditions, reduce energy loss, and improve overall energy efficiency. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the fuel cell flow field plate in Embodiment 1 of the present invention.

[0022] Figure 2 This is a schematic diagram of the block transformation in the flow field plate of the fuel cell according to Embodiment 1 of the present invention.

[0023] Figure 3 This is a schematic diagram of the structure of the fuel cell flow field plate in Embodiment 2 of the present invention.

[0024] Figure 4 This is a schematic diagram of the block transformation in the fuel cell flow field plate of Embodiment 2 of the present invention.

[0025] Attached image labels:

[0026] Inlet 1

[0027] Air outlet 2

[0028] Flow channel ridge 3

[0029] end 31

[0030] Flow channel 4

[0031] DC section 41

[0032] Turning section 42

[0033] Sidewall 421

[0034] Block 5

[0035] Channel 6. Detailed Implementation

[0036] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for 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 invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] As described in the background section, while traditional serpentine flow field plates can promote uniform gas distribution and improve the electrochemical reaction efficiency of fuel cells, the gas velocity decreases significantly in the flow channel turning regions. This can easily lead to the accumulation of liquid water in these areas, causing localized flooding, hindering effective gas diffusion, and potentially exacerbating drainage difficulties. Furthermore, when gas flows through a meandering flow channel, it must overcome multiple sharp turns and pressure drops and increased energy losses due to flow channel friction. Particularly at flow field turning points, if a large amount of liquid water accumulates, it will further increase flow resistance, resulting in additional power consumption and ultimately reducing the energy conversion efficiency of the fuel cell.

[0039] To address the aforementioned issues, this invention incorporates a highly absorbent baffle at the flow channel turning section. When the current density is low, the fuel cell produces water slowly. The baffle reduces the gas flow path at the turning section, increasing the gas velocity and improving mass transfer efficiency. Furthermore, the baffle's porous structure allows gas to pass through without significantly increasing pressure drop, thus enhancing fuel cell performance. When a large amount of liquid water exists at the flow channel turning section, the baffle absorbs the water and contracts, preventing flooding, increasing the gas flow path, and reducing flow resistance. During post-shutdown purging, gas flows over the surface and interior of the baffle, carrying away moisture and restoring the baffle's original volume. Specifically, this invention provides a flow field plate for improving fuel cell performance, comprising a flow field plate body, a baffle, a flow channel, and a flow channel ridge, described in detail below.

[0040] like Figure 1 and Figure 3As shown, the flow field plate includes a flow field plate body, an inlet 1, an outlet 2, a flow channel ridge 3, a flow channel 4, and a baffle 5. The flow channel 4 is arranged in a serpentine structure on the flow field plate body. The flow channel 4 includes several direct current sections 41 and turning sections 42. The turning sections 42 connect to the ends of adjacent direct current sections 41, and a flow channel ridge 3 is naturally formed between adjacent direct current sections. The inlet 1 and the outlet 2 are respectively connected to the two ends of the flow channel 4. In this embodiment, the inlet 1 is connected to the inlet of the direct current section 41, and the outlet 2 is connected to the outlet of the direct current section 41. Gas flows into the flow channel 4 from the inlet 1 and flows out of the flow channel 4 from the outlet 2. As an example, such as... Figure 1 and Figure 2 As shown, the baffle 5 is provided in each turning section 42, and can be provided in close contact with the side wall 421 of the turning section 42, so that a channel 6 for gas flow is formed between the baffle 5 and the end 31 of the flow channel ridge 3, such as... Figure 3 and Figure 4 As shown, the baffle 5 can also be set at the end 31 of the flow channel ridge 3, so that a channel 6 for gas flow is formed between the baffle 5 and the side wall 421 of the turning section 42. The baffle 5 has a porous structure, shrinks in volume when absorbing water and recovers in volume when losing water, and its material can be any one of water-absorbing resin, hydrogel, or natural fiber.

[0041] In some embodiments, the shape of the stop 5 is any one of rectangle, concave, triangle, or semicircle.

[0042] In some embodiments, the width of the stop 5 is smaller than the width of the turning section 42 but larger than the width of the flow channel ridge 3, mainly to provide sufficient expansion and contraction space for the porous stop. As an example, the width of the stop 5 is 1mm-2mm, the width of the turning section 42 is 1.5mm-2.5mm, and the width of the flow channel ridge 3 is 0.5mm-1.5mm.

[0043] In some embodiments, the width of the DC section 41 is 1mm-2mm and the depth is 1mm-2mm; the depth of the deflection section 42 is 1mm-2mm; the thickness of the flow channel ridge 3 is 1mm-2mm; and the thickness of the baffle 5 is 1mm-2mm.

[0044] When the fuel cell current density is low and the water production rate is slow, the presence of baffle 5 reduces the channel of the turning section 42. Under the same flow rate, the narrower the channel of the turning section 42, the greater the gas velocity, which improves the gas mass transfer efficiency. Furthermore, baffle 5 has a porous structure with a relatively loose interior, allowing gas to pass through, which helps reduce pressure drop and thus improves the overall performance of the fuel cell. When the fuel cell operates at a high current density, the water production rate inside the cell is faster, and a large amount of liquid water accumulates in the turning section 42. Although the gas velocity is relatively high, it still easily increases the difficulty of drainage, leading to increased gas flow resistance and a significant increase in the pressure drop at the inlet and outlet of the flow channel 4. At this time, baffle 5 can strongly adsorb the accumulated liquid water. As the liquid gradually fills the pores inside baffle 5, due to surface tension, the liquid exerts pressure on the pore walls, causing the volume of baffle 5 to shrink (see...). Figure 2 and Figure 4 The increased gas flow channel at the turning section 42 reduces the pressure drop inside the flow channel 4 and the gas flow resistance, and also significantly reduces the obstruction of liquid water to gas transmission, effectively preventing flooding and ensuring the stable operation of the fuel cell in a high humidity environment.

[0045] After the fuel cell is shut down, a purging procedure must be performed. The purpose of purging is to effectively remove moisture from inside the fuel cell, reduce the risk of icing, protect the membrane electrode assembly, and maintain cell performance. The purging temperature is 50℃-60℃, the purging time is 100s-120s, and the relative humidity is 20%-40%. Figure 2 and Figure 4 As shown, during the purging process, the gas flows through the surface and interior of the baffle 5. Due to the convection of the gas and the evaporation of moisture, the moisture inside the baffle 5 is carried away by the gas, restoring its volume.

[0046] Through the aforementioned automatic adjustment mechanism, fuel cells can automatically optimize their performance under different operating conditions, reduce energy loss, and improve overall energy efficiency.

[0047] The flow field plate in this embodiment is suitable for either the cathode or anode of a fuel cell.

[0048] Example 1

[0049] like Figure 1 and Figure 2 As shown, the width and depth of the direct flow section 41 are 1 mm. The width and thickness of the flow channel ridge 3 are 1 mm. The width and depth of the flow channel turning section 42 are 1.5 mm and 3 mm. The baffle 5 is a rectangular absorbent resin with a length of 3 mm, a width of 1 mm, and a thickness of 1 mm. The baffle 5 is placed at each turning section 42 and is close to the side wall 421 of the turning section 42. A channel 6 for gas flow is formed between the baffle 5 and the end 31 of the flow channel ridge 3.

[0050] When a large amount of liquid water accumulates in the turning section 42, the baffle 5 absorbs water and mainly contracts in a direction perpendicular to the turning section 42 of the flow channel. When it contracts to its maximum extent, the width of the baffle 5 is 0.5 mm, and the distance between the end 31 of the flow channel ridge 3 and the baffle 5 is 1 mm.

[0051] During the purging process, the gas flows through the surface and interior of the baffle 5, and the moisture inside the baffle 5 evaporates and is carried away by the gas, thus restoring the volume of the baffle 5.

[0052] Example 2

[0053] like Figure 3 and Figure 4 As shown, the width and depth of the direct flow section 41 are 1 mm. The width and thickness of the end 31 of the flow channel ridge 3 are 0.5 mm. The width and depth of the flow channel turning section 42 are 1.5 mm, 1 mm, and 3 mm. The baffle 5 is a concave hydrogel with a length of 2 mm, a width of 1.5 mm, and a thickness of 1 mm. The groove length is 0.5 mm and the width is 0.75 mm. The baffle 5 is placed at each turning section 42 and is close to the end 31 of the flow channel ridge 3. A channel 6 for gas flow is formed between the baffle 5 and the side wall 421 of the turning section 42.

[0054] When a large amount of liquid water accumulates in the turning section 42, the baffle 5 absorbs water and mainly contracts in a direction perpendicular to the turning section 42 of the flow channel. When it contracts to its maximum extent, the width of the baffle 5 is 1.25 mm, and the distance between the side wall 421 of the turning section 42 and the baffle 5 is 1 mm.

[0055] During the purging process, the gas flows through the surface and interior of the baffle 5, and the moisture inside the baffle 5 evaporates and is carried away by the gas, thus restoring the volume of the baffle 5.

[0056] In summary, this invention incorporates a highly absorbent baffle in the flow channel turning section of the fuel cell flow field plate. On one hand, when the current density is low and the water production rate is slow, the baffle reduces the gas flow path in the turning section, accelerating the gas flow rate and improving mass transfer efficiency. Simultaneously, the relatively loose interior of the baffle allows gas to pass through, reducing pressure drop and thus improving the overall performance of the fuel cell. On the other hand, when a large amount of liquid water accumulates in the flow channel turning section, the baffle absorbs the water and contracts due to its strong absorbency. This not only reduces the internal pressure drop and gas flow resistance but also significantly reduces the obstruction of gas transport by liquid water, effectively preventing flooding and ensuring stable operation of the fuel cell in high humidity environments. During the purging phase after shutdown, gas flows through the surface and interior of the baffle, carrying away evaporated water and restoring the baffle's volume. Through this automatic adjustment mechanism, the fuel cell can automatically optimize its performance under different operating conditions, reducing energy loss and improving overall energy efficiency.

[0057] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A flow field plate for improving fuel cell performance, characterized in that, It includes the flow field plate body, baffles, flow channels, and flow channel ridges; The flow channel is arranged in a serpentine structure on the flow field plate body. The flow channel includes several direct flow sections and turning sections. The turning sections connect the ends of adjacent direct flow sections, and the flow channel ridge is formed between adjacent direct flow sections. The stop block is positioned at the turning section and is flush against the side wall of the turning section, forming a channel between the stop block and the end of the flow channel ridge; or The baffle is located at the turning section and is close to the end of the flow channel ridge, so that a channel is formed between the baffle and the side wall of the turning section; The block absorbs water and its volume shrinks; it loses water and its volume recovers.

2. The flow field plate for improving fuel cell performance as described in claim 1, characterized in that, The width of the stop block is smaller than the width of the turning section, and the width of the stop block is larger than the width of the flow channel ridge.

3. The flow field plate for improving fuel cell performance as described in claim 2, characterized in that, The width of the stop block is 1mm-2mm, the width of the turning section is 1.5mm-2.5mm, and the width of the flow channel ridge is 0.5mm-1.5mm.

4. The flow field plate for improving fuel cell performance as described in claim 1, characterized in that, The shape of the stop block can be any one of rectangle, concave, triangle, or semicircle.

5. The flow field plate for improving fuel cell performance as described in claim 1, characterized in that, The material of the block is any one of water-absorbing resin, hydrogel, or natural fiber.

6. The flow field plate for improving fuel cell performance as described in claim 1, characterized in that, The stop block has a porous structure.

7. The flow field plate for improving fuel cell performance as described in claim 1, characterized in that, The stop is provided at each of the aforementioned steering segments.

8. The flow field plate for improving fuel cell performance as described in claim 1, characterized in that, It also includes an air inlet and an air outlet, which are respectively connected to the two ends of the flow channel. Gas flows into the flow channel from the air inlet and flows out of the flow channel from the air outlet.

9. The flow field plate for improving fuel cell performance as described in claim 1, characterized in that, The width of the DC section is 1mm-2mm and the depth is 1mm-2mm; the depth of the deflection section is 1mm-2mm; the thickness of the flow channel ridge is 1mm-2mm; and the thickness of the baffle is 1mm-2mm.

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