SOFC (solid oxide fuel cell) multi-channel snakelike flow field with gradient rib layout

Abstract

The invention provides an SOFC (Solid Oxide Fuel Cell) multi-channel snakelike flow field with gradient rib layout, and belongs to the technical field of fuel cells. The SOFC multi-channel snakelike flow field comprises gradient ribs, strip-shaped ribs and a snakelike flow channel, the gradient ribs are arranged on the two sides of a U-shaped structure of the snakelike flow channel, and the strip-shaped ribs are arranged at the bottom of the U-shaped structure of the snakelike flow channel. The multi-channel snakelike flow field is combined with the gradient rib structure, a multi-channel inlet reduces the number of flow channel bending times, reduces the gas accumulation risk, avoids the problems of insufficient gas supply and the like, and the gradient rib layout is beneficial to gas mixing diffusion, mass transfer enhancement, pressure drop reduction and net power density improvement.

Description

Technical Field

[0001] The present invention belongs to the technical field of fuel cells, and in particular relates to a SOFC multi-channel serpentine flow field with a gradient rib layout. Background Art

[0002] Against the backdrop of increasingly scarce global oil resources and intensifying climate change, hydrogen, as a zero-carbon energy carrier, has become a core focus of the clean energy transition. Fuel cells, by breaking through the limitations of the Carnot cycle and directly converting the chemical energy of fuel into electricity, offer extremely high energy conversion efficiency and are considered one of the most promising power technologies.

[0003] Solid oxide fuel cells (SOFCs) hold a strategic position in the distributed energy supply sector due to their strong fuel adaptability and high waste heat utilization value. However, their industrialization faces severe challenges: the traditional single-channel serpentine flow field has an excessively long flow channel, resulting in insufficient concentration of the reactant gas at the end, causing localized mass transfer degradation and performance degradation. Furthermore, the multiple bends in the flow channel cause excessive pressure drop and high parasitic power loss. Furthermore, the connector structure that matches the serpentine flow field is poorly optimized, and traditional strip ribs cannot adapt to the dynamic transport requirements of gas, further exacerbating concentration polarization losses. Summary of the Invention

[0004] In response to the problems existing in the above-mentioned prior art, the present invention provides a SOFC multi-channel serpentine flow field with a gradient rib layout, and proposes a flow field-connector collaborative optimization structure: through a multi-channel diversion design to balance the contradiction between flow channel length and pressure drop, combined with a gradient rib layout to enhance gas mixing and diffusion, thereby improving SOFC performance.

[0005] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0006] The present invention provides a SOFC multi-channel serpentine flow field with a gradient rib layout, comprising gradient ribs, strip ribs and serpentine flow channels, wherein the gradient ribs are arranged on both sides of a U-shaped structure of the serpentine flow channel, and the strip ribs are arranged at the bottom of the U-shaped structure of the serpentine flow channel. A gas inlet is arranged at one end of the SOFC multi-channel serpentine flow field with a gradient rib layout, and a gas outlet is arranged at the other end.

[0007] Furthermore, the gradient ribs are right-angled trapezoidal prisms, and the orientations of the right-angled trapezoidal prisms near the gas inlet side, the middle position, and the gas outlet side are different; the inclined edge of the right-angled trapezoidal prism near the gas inlet side is set on the leeward side of the gas flow and the lower end of the inclined edge is close to the gas inlet side; the inclined edge of the right-angled trapezoidal prism near the gas outlet side is set on the windward side of the gas flow and the lower end of the inclined edge is close to the gas outlet side; the inclined edge of the right-angled trapezoidal prism in the middle position is set on the leeward side of the gas flow and the lower end of the inclined edge is close to the gas inlet side.

[0008] Furthermore, one end of the SOFC multi-channel serpentine flow field with a gradient rib layout is a gas fuel or air inlet, and the other end of the SOFC multi-channel serpentine flow field with a gradient rib layout is a residual gas fuel or air outlet, that is, the gas fuel or air enters from the inlet, diffuses through the serpentine flow channel, and then flows out from the outlet at the other end.

[0009] Furthermore, the single-side side rib of the U-shaped structure at the middle position and at the junction close to the gas outlet side is configured as a strip rib or a gradient rib.

[0010] Furthermore, the serpentine flow channel is configured as at least five channels.

[0011] Furthermore, the gradient ribs are arranged at equal distances along the direction of the serpentine flow channel.

[0012] Furthermore, the width of the serpentine flow channel is 2 mm, the height of the serpentine flow channel is 1 mm, and the width of the gradient ribs and the strip ribs are both 2 mm and the height are both 1 mm.

[0013] Furthermore, the upper base of the right-angled trapezoid of the right-angled trapezoidal prism is 1 mm, the lower base is 2 mm, and the height is 2 mm, and the height of the right-angled trapezoidal prism is 1 mm.

[0014] Furthermore, the gradient ribs are arranged at equal distances along the serpentine flow channel at a spacing of 4 mm.

[0015] The present invention has the following beneficial effects: the multi-channel serpentine flow field proposed in the present invention is combined with a gradient rib structure, and the multi-channel inlet reduces the number of flow channel bends, reduces the risk of gas accumulation, and avoids problems such as insufficient gas supply. The gradient rib layout is conducive to gas mixing and diffusion and enhanced mass transfer, reduces pressure drop, and improves net power density. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a structural diagram of the traditional strip-rib five-channel serpentine flow field.

[0017] Figure 2 Schematic diagram of the SOFC five-channel serpentine flow field structure with gradient rib layout provided in Example 1.

[0018] Figure 3 Schematic diagram of the gradient rib orientation layout of the five-channel serpentine flow field of the SOFC with gradient rib layout provided in Example 1.

[0019] Figure 4 Schematic diagram of the gradient rib structure provided in Example 1.

[0020] Figure 5 Schematic diagram of the SOFC five-channel serpentine flow field structure with gradient rib layout provided in Example 2.

[0021] Figure 6 Schematic diagram of the gradient rib orientation layout of the five-channel serpentine flow field of the SOFC with gradient rib layout provided in Example 2.

[0022] Figure 7 Polarization curves and power density curves of three examples at two inlet velocities.

[0023] Figure 8 The hydrogen mole fraction distribution cloud diagram of the three examples when the working voltage is 0.3 V.

[0024] Figure 9 The pressure distribution cloud diagrams on the cathode side of the three examples are shown when the working voltage is 0.3 V.

[0025] Marking instructions in the figure: 1- gradient rib, 2- strip rib, 3- another strip rib. DETAILED DESCRIPTION

[0026] The present invention is described in further detail below with reference to the embodiments and accompanying drawings.

[0027] Example 1:

[0028] like Figure 1 As shown, it is a traditional strip-rib five-channel serpentine flow field, the length and width of the flow field are 60 mm and 40 mm respectively, the serpentine flow channel width is 2 mm, and the serpentine flow channel height is 1 mm.

[0029] In this embodiment, the bipolar plate material is a metal plate with high mechanical strength.

[0030] like Figure 2 and Figure 3 As shown, the present invention provides a five-channel serpentine flow field with a gradient rib layout for SOFC, comprising gradient ribs 1, strip ribs 2, and serpentine flow channels. The flow field has a length and width of 60 mm and 40 mm, respectively, while the serpentine flow channels are 2 mm wide and 1 mm high.

[0031] The serpentine flow channel is set to five channels. Figure 1 The serpentine flow channels of channel I, channel II, channel III, channel IV, and channel V shown are consistent.

[0032] The gradient ribs 1 and the strip ribs 2 have a width of 2 mm and a height of 1 mm.

[0033] The gradient ribs 1 are set on both sides of the U-shaped structure of the serpentine flow channel, and the strip ribs 2 are set at the bottom of the U-shaped structure of the serpentine flow channel. The single-side ribs of the U-shaped structure at the middle position and near the junction of the gas outlet side are also set as gradient ribs, such as Figure 2 、 3 shown.

[0034] like Figure 4 As shown, the gradient ribs are rectangular trapezoidal prisms with an upper base of 1 mm, a lower base of 2 mm, and a height (i.e., the gradient rib width) of 2 mm. The height of the rectangular trapezoidal prisms is 1 mm. The gradient ribs are arranged equidistantly along the serpentine flow path, with a spacing of 4 mm.

[0035] like Figure 2 、 3 As shown, the orientations of the right-angled trapezoidal prisms near the gas inlet side, the middle position, and the gas outlet side are different; the inclined edge of the right-angled trapezoidal prism near the gas inlet side is set on the leeward side of the gas flow direction and the lower end of the inclined edge is close to the gas inlet side; the inclined edge of the right-angled trapezoidal prism near the gas outlet side is set on the windward side of the gas flow direction and the lower end of the inclined edge is close to the gas outlet side; the inclined edge of the right-angled trapezoidal prism at the middle position is set on the leeward side of the gas flow direction and the lower end of the inclined edge is close to the gas inlet side.

[0036] like Figure 3 As shown, one end of the SOFC five-channel serpentine flow field with a gradient rib layout is the gas fuel or air inlet, and the other end is the residual gas fuel or air outlet, that is, the gas fuel or air enters from the inlet, diffuses through the serpentine flow channel, and then flows out from the outlet at the other end.

[0037] The five channel entrances reduce the number of flow channel bends, lower the risk of gas accumulation, and avoid problems such as insufficient gas supply. The gradient rib layout is conducive to gas mixing and diffusion and enhanced mass transfer, reducing pressure drop and improving net power density.

[0038] Example 2:

[0039] Based on Example 1, Example 2 provides a five-channel serpentine flow field of SOFC with a gradient rib layout, including a gradient rib 1, a strip rib 2 and a serpentine flow channel consistent with Example 1, except that the single-side side rib of the U-shaped structure at the junction in the middle position and close to the gas outlet side is set as another strip rib 3, such as Figure 5 、 6 shown.

[0040] like Figure 6 As shown, one end of the SOFC five-channel serpentine flow field with a gradient rib layout is the gas fuel or air inlet, and the other end is the residual gas fuel or air outlet, that is, the gas fuel or air enters from the inlet, diffuses through the five-channel serpentine flow channel, and then flows out from the outlet at the other end.

[0041] The contradiction between flow channel length and pressure drop is balanced through the five-channel diversion design, and the gradient rib layout is combined to enhance gas mixing and diffusion. The strip rib 3 structure is retained at the end of the flow channel to improve the reaction rate.

[0042] On this basis, the five-channel serpentine flow field of SOFC with gradient rib layout in Example 1 (structure as shown in FIG Figure 2-3 As shown), the SOFC five-channel serpentine flow field with gradient rib layout of Example 2 (structure as shown Figure 5-6 As shown) and the traditional strip rib five-channel serpentine flow field (structure as shown Figure 1 As shown in the figure, they are defined as Example 1, Example 2, and Example 3 respectively. Numerical simulation analysis was performed using COMSOL Multiphysics software, and the results are as follows:

[0043] Figure 7 The polarization curves and power density curves of three examples at two inlet velocities are shown, corresponding to the working conditions of Va=0.72m / s, Vc=1.8m / s and Va=1.08m / s, Vc=2.7m / s. Figure 7 The results show that at the two inlet velocities, the electrochemical performance of Examples 1 and 2 is better than that of Example 3, with Example 2 performing best. This indicates that the electrochemical performance of the five-channel serpentine flow field with gradient ribs is better than that of the traditional five-channel serpentine flow field with strip ribs.

[0044] Figure 8 The hydrogen mole fraction distribution cloud diagrams for the three examples at an operating voltage of 0.3 V are shown. As shown in the figure, the hydrogen mole fraction of Example 3 decreases significantly along the flow direction, and its mole fraction at the outlet is lower than that of Examples 1 and 2, indicating that the gas concentration difference within its flow field is the largest and the distribution is the most uneven. The minimum hydrogen mole fractions of Examples 1 to 3 are 0.605, 0.611, and 0.485, respectively. Because the gradient rib layout has a lower restrictive effect on gas flow than traditional strip ribs and lowers gas diffusion resistance, Examples 1 and 2 significantly improve the uniformity of hydrogen distribution and reduce the concentration gradient compared to Example 3. This allows Examples 1 and 2 to maintain a higher gas concentration at the tail end of the flow channel, resulting in better overall performance. Compared with Example 1, Example 2 retains the traditional rib design on the left side of the outlet. Under the restriction of the ribs, gas accumulates in the middle of the flow field and flows out faster at the outlet, enhancing the mass transfer effect in the outlet area and achieving better electrochemical performance than Example 1.

[0045] Figure 9 The cathode-side pressure distribution cloud diagrams for three examples at an operating voltage of 0.3 V are shown. The maximum cathode-side pressures for Examples 1 to 3 are 69.5 Pa, 104.7 Pa, and 212.2 Pa, respectively. In the five-channel serpentine flow field with strip ribs (Example 3), the gas must make multiple turns, causing gas accumulation and a significant increase in the pressure drop within the flow channel. In contrast, the trapezoidal prismatic rib structure of the five-channel serpentine flow field with gradient ribs (Examples 1 and 2) effectively guides gas flow and reduces flow resistance, resulting in a significant reduction in pressure drop.

[0046] Batteries using the present invention's five-channel serpentine flow field with gradient ribs exhibit superior electrochemical performance compared to conventional strip-ribbed five-channel serpentine flow fields. The gradient rib design effectively promotes gas mixing and mass transfer, reduces pressure drop between the cathode and anode sides, and improves net power density.

Claims

1. A multi-channel serpentine flow field for SOFC with a gradient rib layout, characterized by: It includes gradient ribs, strip ribs and serpentine flow channels. The gradient ribs are arranged on both sides of the U-shaped structure of the serpentine flow channel, and the strip ribs are arranged at the bottom of the U-shaped structure of the serpentine flow channel. The SOFC multi-channel serpentine flow field with gradient rib layout has a gas inlet at one end and a gas outlet at the other end.

2. The SOFC multi-channel serpentine flow field with gradient rib layout according to claim 1, characterized in that: The gradient ribs are right-angled trapezoidal prisms, and the orientations of the right-angled trapezoidal prisms near the gas inlet side, the middle position, and the gas outlet side are different; the inclined edge of the right-angled trapezoidal prism near the gas inlet side is arranged on the leeward side of the gas flow direction and the lower end of the inclined edge is close to the gas inlet side; the inclined edge of the right-angled trapezoidal prism near the gas outlet side is arranged on the windward side of the gas flow direction and the lower end of the inclined edge is close to the gas outlet side; the inclined edge of the right-angled trapezoidal prism in the middle position is arranged on the leeward side of the gas flow direction and the lower end of the inclined edge is close to the gas inlet side.

3. The SOFC multi-channel serpentine flow field with gradient rib layout according to claim 1, characterized in that: One end of the SOFC multi-channel serpentine flow field with a gradient rib layout is a gas fuel or air inlet, and the other end of the SOFC multi-channel serpentine flow field with a gradient rib layout is a residual gas fuel or air outlet, that is, the gas fuel or air enters from the inlet, diffuses through the serpentine flow channel, and then flows out from the outlet at the other end.

4. The SOFC multi-channel serpentine flow field with gradient rib layout according to claim 1, characterized in that: The single-side side ribs of the U-shaped structure at the junction in the middle position close to the gas outlet side are configured as strip ribs or gradient ribs.

5. The SOFC multi-channel serpentine flow field with gradient rib layout according to claim 1, characterized in that: The serpentine flow channel is configured to have at least five channels.

6. The SOFC multi-channel serpentine flow field with gradient rib layout according to claim 1, characterized in that: The gradient ribs are arranged at equal distances along the direction of the serpentine flow channel.

7. The SOFC multi-channel serpentine flow field with gradient rib layout according to claim 1, characterized in that: The width of the serpentine flow channel is 2 mm, the height of the serpentine flow channel is 1 mm, and the width of the gradient ribs and the strip ribs are both 2 mm, and the height is both 1 mm.

8. The SOFC multi-channel serpentine flow field with gradient rib layout according to claim 2, characterized in that: The upper base of the right-angled trapezoid of the right-angled trapezoidal prism is 1 mm, the lower base is 2 mm, and the height is 2 mm. The height of the right-angled trapezoidal prism is 1 mm.

9. The SOFC multi-channel serpentine flow field with gradient rib layout according to claim 6, characterized in that: The gradient ribs are arranged equidistantly along the serpentine flow channel at a spacing of 4 mm.

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