A multi-channel serpentine flow field of SOFC with gradient ribs

Abstract

This invention provides a multi-channel serpentine flow field for SOFC with a gradient rib layout, belonging to the field of fuel cell technology. The SOFC multi-channel serpentine flow field includes gradient ribs, strip ribs, and serpentine channels. The gradient ribs are located on both sides of the U-shaped structure of the serpentine channel, and the strip ribs are located at the bottom of the U-shaped structure. This invention proposes a multi-channel serpentine flow field combined with a gradient rib structure. The multi-channel inlet reduces the number of bends in the flow channel, lowers the risk of gas accumulation, and avoids problems such as insufficient gas supply. The gradient rib layout is beneficial for gas mixing and diffusion and enhances mass transfer, reducing pressure drop and increasing net power density.

Description

Technical Field

[0001] This invention belongs to the field of fuel cell technology, specifically relating to a multi-channel serpentine flow field in SOFC with a gradient rib layout. Background Technology

[0002] Against the backdrop of increasingly scarce global oil resources and escalating climate change, hydrogen energy, as a zero-carbon energy carrier, has become a core focus of the clean energy transition. Fuel cells, with their ability to overcome the Carnot cycle limitations, can directly convert the chemical energy of fuel into electrical energy, exhibiting 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 field of distributed energy supply due to their advantages such as strong fuel adaptability and high waste heat utilization value. However, their industrialization process faces severe challenges: the traditional single-channel serpentine flow field results in insufficient concentration of reactant gas at the end due to excessive flow channel length, leading to local mass transfer deterioration and performance degradation; at the same time, multiple bends in the flow channel cause excessive pressure drop and excessive parasitic power loss; in addition, there is little optimization of the connector structure to match the serpentine flow field, and the traditional strip ribs cannot adapt to the dynamic gas transport requirements, further aggravating concentration polarization loss. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a multi-channel serpentine flow field for SOFC with a gradient rib layout, and proposes a flow field-connector collaborative optimization structure: by balancing the contradiction between flow channel length and pressure drop through multi-channel diversion design, and by combining gradient rib layout to enhance gas mixing and diffusion, the performance of SOFC is improved.

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

[0006] The present invention provides a multi-channel serpentine flow field of SOFC with gradient ribs, including 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 multi-channel serpentine flow field of SOFC with gradient ribs is provided with a gas inlet at one end and a gas outlet at the other end.

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

[0008] Furthermore, one end of the SOFC multi-channel serpentine flow field with gradient ribs is the gaseous fuel or air inlet, and the other end of the SOFC multi-channel serpentine flow field with gradient ribs is the residual gaseous fuel or air outlet. That is, the gaseous fuel or air enters from the inlet, diffuses through the serpentine flow channel, and then flows out from the other end outlet.

[0009] Furthermore, the single-sided ribs of the U-shaped structure at the junction in the middle position and near the gas outlet side are set as strip ribs or gradient ribs.

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

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

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

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

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

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

[0016] Figure 1 This is a schematic diagram of a traditional strip-ribbed five-channel serpentine flow field.

[0017] Figure 2 A schematic diagram of the SOFC five-channel serpentine flow field structure with gradient ribs provided in Example 1.

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

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

[0020] Figure 5 This is a schematic diagram of the SOFC five-channel serpentine flow field structure with gradient ribs provided in Example 2.

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

[0022] Figure 7 The graphs show the polarization curves and power density curves for three examples at two inlet velocities.

[0023] Figure 8 The hydrogen mole fraction distribution cloud map is shown for the three examples when the operating voltage is 0.3 V.

[0024] Figure 9 The cathode-side pressure distribution contour plots are for three examples when the operating voltage is 0.3 V.

[0025] The markings in the diagram are as follows: 1-gradient rib, 2-strip rib, 3-another strip rib. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings.

[0027] Example 1:

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

[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, this invention provides a five-channel serpentine flow field for SOFC with a gradient rib layout, including gradient rib 1, strip rib 2, and serpentine flow channel. The length and width of the flow field are 60 mm and 40 mm, respectively, the width of the serpentine flow channel is 2 mm, and the height of the serpentine flow channel is 1 mm.

[0031] The serpentine flow channel is configured with five channels, and the serpentine flow channel is combined with... Figure 1 The serpentine flow paths shown in channels I, II, III, IV, and V are consistent.

[0032] The gradient rib 1 and the strip rib 2 are both 2mm wide and 1mm high.

[0033] Gradient ribs 1 are positioned on both sides of the U-shaped structure of the serpentine flow channel, while strip ribs 2 are positioned at the bottom of the U-shaped structure. The single-sided side ribs of the U-shaped structure at the midpoint and near the gas outlet are also designed as gradient ribs, such as... Figure 2 , 3 As shown.

[0034] like Figure 4 As shown, the gradient ribs are right-angled trapezoidal prisms with an upper base of 1mm, a lower base of 2mm, and a height (i.e., gradient rib width) of 2mm. The height of the right-angled trapezoidal prism is 1mm. The gradient ribs are arranged at equal intervals along the serpentine flow channel with a spacing of 4mm.

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

[0036] like Figure 3 As shown, one end of the SOFC five-channel serpentine flow field with gradient ribs is the gaseous fuel or air inlet, and the other end is the residual gaseous fuel or air outlet. That is, the gaseous 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] Five inlet channels reduce the number of bends in the flow path, lower the risk of gas buildup, and avoid problems such as insufficient gas supply. The gradient rib layout is conducive to gas mixing and diffusion and enhances mass transfer, reducing pressure drop and increasing net power density.

[0038] Example 2:

[0039] Based on Example 1, Example 2 provides a five-channel serpentine flow field for SOFC with a gradient rib layout, including the same gradient rib 1, strip rib 2, and serpentine flow channel as in Example 1. The difference is that the single-side rib of the U-shaped structure at the junction in the middle position and near the gas outlet side is replaced by another strip rib 3, as shown below. Figure 5 , 6 As shown.

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

[0041] The five-channel diversion design balances the contradiction between channel length and pressure drop, and the gradient rib layout enhances gas mixing and diffusion. The presence of strip ribs at the end of the channel can improve the reaction rate.

[0042] Based on this, the SOFC five-channel serpentine flow field with gradient rib layout in Example 1 (structure as follows) Figure 2-3 As shown), the SOFC five-channel serpentine flow field with gradient rib layout in Example 2 (structure as shown) Figure 5-6 As shown) and the traditional strip-ribbed five-channel serpentine flow field (structure as shown) Figure 1 As shown in the figure, these 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 for three examples at two inlet velocities are shown, corresponding to the following operating conditions: Va=0.72m / s, Vc=1.8 m / s and Va=1.08m / s, Vc=2.7 m / s. Figure 7 The results show that, at both inlet velocities, the electrochemical performance of Examples 1 and 2 is superior to that of Example 3, with Example 2 exhibiting the best performance. This indicates that the electrochemical performance of the five-channel serpentine flow field with gradient ribs is superior to that of the conventional strip-rib five-channel serpentine flow field.

[0044] Figure 8 The figure shows the hydrogen mole fraction distribution contour plots for three examples at an operating voltage of 0.3 V. As shown, the hydrogen mole fraction in Example 3 decreases significantly along the flow direction, and its outlet mole fraction is lower than that in Examples 1 and 2, indicating that it has the largest gas concentration difference and the most uneven distribution within the flow field. The minimum hydrogen mole fractions for Examples 1 to 3 are 0.605, 0.611, and 0.485, respectively. Since the gradient rib layout has a lower restrictive effect on gas flow than the traditional strip rib, the gas diffusion resistance is smaller. Therefore, Examples 1 and 2 significantly improve the uniformity of hydrogen gas 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 to Example 1, Example 2 retains the traditional rib design on the left side of the outlet. Under the restriction of the rib, the gas accumulates in the middle section of the flow field and accelerates its outflow at the outlet section, enhancing the mass transfer effect in the outlet region, and its electrochemical performance is better than that of Example 1.

[0045] Figure 9 The diagrams show the cathode-side pressure distribution contours for three examples at an operating voltage of 0.3 V. The maximum cathode-side pressures for Examples 1 to 3 are 69.5 Pa, 104.7 Pa, and 212.2 Pa, respectively. In the strip-ribbed five-channel serpentine flow field (Example 3), the gas needs to change direction multiple times, leading to gas accumulation and a significant increase in pressure drop within the flow channel. In contrast, the trapezoidal prism rib structure of the gradient-ribbed five-channel serpentine flow fields (Examples 1 and 2) effectively guides gas flow and reduces flow resistance, thus significantly reducing their pressure drops.

[0046] The batteries employing the five-channel serpentine flow field with gradient ribs of this invention all exhibit superior electrochemical performance compared to the traditional strip-rib five-channel serpentine flow field. The gradient rib design effectively promotes gas mixing and mass transfer, reduces the pressure drop on the cathode and anode sides, and increases the net power density.

Claims

1. A multi-channel serpentine flow field of SOFC with gradient ribs, characterized in that: 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 ribs has a gas inlet at one end and a gas outlet at the other end. The gradient ribs are right-angled trapezoidal prisms, with different orientations for the right-angled trapezoidal prisms near the gas inlet, in the middle, and near the gas outlet. The inclined side of the right-angled trapezoidal prism near the gas inlet is located on the leeward side of the gas flow direction, and the lower end of the inclined side is close to the gas inlet. The inclined side of the right-angled trapezoidal prism near the gas outlet is located on the windward side of the gas flow direction, and the lower end of the inclined side is close to the gas outlet. The inclined side of the right-angled trapezoidal prism in the middle is located on the leeward side of the gas flow direction, and the lower end of the inclined side is close to the gas inlet. The right trapezoidal prism has an upper base of 1mm, a lower base of 2mm, and a height of 2mm, and the height of the right trapezoidal prism is 1mm.

2. 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 gradient ribs is the gaseous fuel or air inlet, and the other end is the residual gaseous fuel or air outlet. That is, the gaseous fuel or air enters from the inlet, diffuses through the serpentine flow channel, and then flows out from the other end outlet.

3. The SOFC multi-channel serpentine flow field with gradient rib layout according to claim 1, characterized in that: The single-sided ribs of the U-shaped structure at the junction in the middle and near the gas outlet are set as strip ribs or gradient ribs.

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

5. A multi-channel serpentine flow field with gradient ribs according to claim 1, characterized in that: The gradient ribs are arranged at equal intervals along the serpentine flow channel.

6. The SOFC multi-channel serpentine flow field with gradient rib layout according to claim 1, characterized in that: The serpentine flow channel has a width of 2mm and a height of 1mm. The gradient ribs and strip ribs both have a width of 2mm and a height of 1mm.

7. A multi-channel serpentine flow field with gradient ribs according to claim 5, characterized in that: The gradient ribs are arranged at equal intervals along the serpentine flow channel with a spacing of 4 mm.

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