Solid oxide electrolysis cell interconnects with slotted rib structure and electrolysis cell stack based thereon

Abstract

The application discloses a solid oxide electrolysis cell connector with a slotted rib structure and an electrolysis cell stack based on the same, and belongs to the technical field of solid oxide electrolysis cells. The connector disclosed by the application comprises a connector base body; the upper and lower surfaces of the connector base body are respectively provided with a plurality of spaced rectangular straight ribs, and a gas flow channel is formed between adjacent rectangular straight ribs; a plurality of slots are arranged on at least one side of the rectangular straight rib and are spaced apart along the length direction; the slot extends inward from the side of the rectangular straight rib along the rib width direction; the depth of the slot is smaller than the rib width of the rectangular straight rib, so that the slot does not penetrate through the rectangular straight rib; the slots on the two sides of the same rectangular straight rib are alternately and staggeredly arranged along the length direction of the rib; and the upper and lower edges and the left and right edges of the connector base body are respectively provided with a second group of through holes for fuel gas flow and a first group of through holes for purge gas flow. The problem that the existing connector has the disadvantage that gas diffusion is difficult in the rib lower area is solved.

Description

Technical Field

[0001] This invention belongs to the field of solid oxide electrolytic cell technology, specifically relating to a slotted rib structure solid oxide electrolytic cell connector and an electrolytic cell stack based thereon. Background Technology

[0002] With the continuous growth of global energy demand and the increasing depletion of traditional fossil fuel reserves, fossil fuels, represented by coal, oil, and natural gas, not only struggle to meet the needs of long-term sustainable development, but their combustion processes also emit large amounts of greenhouse gases such as carbon dioxide, exacerbating global climate change. While renewable energy sources such as wind and solar power offer advantages in terms of cleanliness and environmental friendliness, their output power is intermittent and fluctuating, making it difficult to directly match user energy demands. Therefore, they must be combined with efficient energy storage technologies to improve their absorption and utilization rates. Hydrogen energy, as a clean and efficient secondary energy carrier, boasts the highest energy density per unit mass and achieves zero carbon emissions at the point of use, making it considered an ideal energy storage medium and a key component of the future energy system. The core bottleneck for the development and large-scale application of hydrogen energy lies in efficient and inexpensive hydrogen production technology. Solid oxide electrolysis cells (SOECs) can convert electrical and thermal energy into chemical energy under high-temperature conditions, offering advantages such as high hydrogen production rates, high theoretical hydrogen production efficiency, and the elimination of the need for precious metal catalysts. It is a hydrogen production device with great development potential and has received extensive research and development from academia and industry in recent years.

[0003] The connector is one of the main components constituting the SOEC electrolytic cell stack. Located between two electrolytic cell plates, the connector primarily functions to isolate the fuel flow channel from the air flow channel, guide gas flow in the fuel and air flow channels, and form a current path. The connector affects the distribution of physical fields such as flow field, temperature field, and electric field inside the SOEC, playing a crucial role in the electrolytic performance and internal reaction distribution of the SOEC. Existing methods using metal foam as the flow channel structure for SOEC can provide electrodes with good diffusion and conductivity conditions simultaneously, but they perform poorly in terms of flow resistance and airflow guidance, and the internal tortuous conductive path itself has high resistance. The rectangular straight-rib structure is currently the most commonly used SOEC connector structure. Its wide and straight flow provides low flow resistance and good airflow guidance capabilities. While the conductivity condition under the ribs is good, gas diffusion is difficult, and the flow channel region is the opposite, which limits further increases in electrolytic cell power under this structure. To address the drawback of poor water vapor diffusion in the rib region under existing rectangular straight-rib structures, grooves are made on both sides of the ribs to improve the diffusion conditions in the rib region and thus enhance the electrolytic performance of the SOEC. Summary of the Invention

[0004] The purpose of this invention is to provide a slotted rib structure solid oxide electrolytic cell connector and an electrolytic cell stack based thereon, which solves the disadvantage of existing connectors having difficulty in gas diffusion in the under-rib region.

[0005] To achieve the above objectives, the present invention employs the following technical solution: This invention discloses a slotted rib structure solid oxide electrolytic cell connector, including a connector substrate; the upper and lower surfaces of the connector substrate are respectively provided with a plurality of spaced rectangular straight ribs, and gas flow channels are formed between adjacent rectangular straight ribs; On both sides of at least one rectangular straight rib, a plurality of slots are spaced apart along the length direction; the slots extend inward from the side of the rectangular straight rib along the rib width direction; the depth of the slots is less than the rib width of the rectangular straight rib, so that the slots do not penetrate the rectangular straight rib; the slots on the two sides of the same rectangular straight rib are arranged alternately and staggered along the length direction of the rib. The upper and lower edges and the left and right edges of the connector substrate are respectively provided with a second set of through holes for fuel gas flow and a first set of through holes for purging gas flow.

[0006] Furthermore, the height of the slot is the same as the height of the rectangular straight rib and is consistent with the height of the gas flow channel.

[0007] Furthermore, the first set of through holes and the second set of through holes are respectively connected to the gas flow channel on the same side.

[0008] Furthermore, the width of the rectangular straight rib is greater than the width of the gas flow channel.

[0009] Furthermore, the slots are spaced equally on one side of the rectangular straight rib.

[0010] Furthermore, the rectangular straight ribs on the upper and lower surfaces of the connecting body substrate are arranged in an alternating flow pattern, that is, the extending directions of the rectangular straight ribs on the upper and lower surfaces are perpendicular to each other.

[0011] Furthermore, the slot is a rectangular slot, the width of which extends along the length of the rib.

[0012] Furthermore, the central region of the solid oxide electrolytic cell connector with the slotted rib structure is the flow field region where the rectangular straight ribs are set, and the slots are only set on the rectangular straight ribs at non-edge positions.

[0013] Furthermore, the upper and lower surfaces of the connector are respectively provided with gas buffers, which are located between the flow channel and the corresponding second set of through holes.

[0014] The present invention also discloses a solid oxide electrolytic cell stack, comprising at least two electrolytic cell plates and at least one solid oxide electrolytic cell connector with a slotted rib structure as described above; The connector is disposed between two adjacent electrolytic cell plates. The rectangular straight ribs on the upper surface of the connector are in contact with the cathode of one electrolytic cell plate, and the rectangular straight ribs on the lower surface of the connector are in contact with the anode of the other electrolytic cell plate.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a slotted rib structure connector for a solid oxide electrolytic cell. By setting rectangular straight ribs on the surface of the connector substrate and creating alternating, non-penetrating slots on both sides of the rectangular straight ribs, additional rapid diffusion channels are provided for the gas below the ribs. This significantly shortens the diffusion distance of the gas in the tortuous pores inside the electrode, thereby effectively reducing concentration polarization. Simultaneously, this structure eliminates the low-concentration gas region under the ribs, greatly improving the uniformity of the electrochemical reaction inside the electrolytic cell. Furthermore, since the slots do not penetrate the ribs, the main contact area between the ribs and the electrode is preserved, avoiding a significant increase in ohmic polarization. While retaining the advantages of the original rectangular straight rib structure, the gas diffusion conditions in the region under the ribs are improved, thereby further enhancing the electrolytic performance of SOEC.

[0016] Furthermore, by setting the rib width to be greater than the flow channel width, the contact area between the rib and the electrode is increased, providing more current conduction paths and effectively reducing ohmic polarization. In synergy with the slotting setting, it not only retains the advantage of the rib in reducing ohmic polarization, but also makes up for the diffusion bottleneck caused by the wide rib through the slotting, thereby breaking through the contradiction between the inverse relationship between ohmic polarization and concentration polarization in traditional designs.

[0017] Furthermore, by arranging the upper and lower surface ribs in a staggered flow pattern (with their extension directions perpendicular to each other), the fuel gas and air can form a cross flow on both sides of the electrolytic cell, which can significantly improve the uniformity of gas distribution over a large area of ​​the entire electrolytic cell, avoid local depletion of reactants or overheating, and improve the overall electrolysis performance and thermal management capabilities.

[0018] Furthermore, the slots are only placed on the ribs at non-edge locations. The edge ribs are close to the gas buffer zone, where the gas diffusion conditions are already better, so there is no need for slots. The slots are only placed on the ribs in the central region where the diffusion conditions are poor, which can precisely solve the gas diffusion problem while minimizing processing costs and structural weakening. Attached Figure Description

[0019] Figure 1 This is an isometric view of the slotted rib structure of the solid oxide electrolytic cell connector of the present invention; Figure 2 This is a top view of the slotted rib structure solid oxide electrolytic cell connector of the present invention; Figure 3 This is a partially enlarged view of the slotted rib structure of the solid oxide electrolytic cell connector of the present invention; Figure 4 The simulated water vapor concentration distribution within a SOEC is based on the design of the slotted rib structure connector of the present invention. Figure 5 The simulated current density distribution within the SOEC under the design of the slotted rib structure solid oxide electrolytic cell connector of the present invention; The components include: 1. Connector base; 2. Gas buffer zone; 3. Flow channel; 4. Rectangular straight rib; 5. First set of through holes; 6. Second set of through holes; 7. Groove. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0021] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] The present invention will now be described in further detail with reference to the accompanying drawings: This invention discloses a slotted rib structure solid oxide electrolytic cell connector, including, for example... Figures 1-3 As shown, the main features include a connector substrate 1, a gas buffer zone 2, a flow channel 3, a rectangular straight rib 4, a first set of through holes 5, a second set of through holes 6, and a slot 7.

[0023] Example 1 by Figure 1The upper surface is the fuel side, and the lower surface is the air side. The connector base 1 has a square plate structure. The upper and lower surfaces are provided with several rectangular straight ribs 4 with constant rib width. A flow channel 3 for gas flow is formed between adjacent rectangular straight ribs 4. The rib width of the rectangular straight ribs 4 is greater than the width of the flow channel 3 to increase the contact area between the ribs 4 and the electrodes and reduce the contact resistance and ohmic polarization. The upper and lower surfaces of the connector base 1 are provided with gas buffer zones 2. The upper and lower edges and the left and right edges of the connector 1 are provided with a first set of through holes 5 and a second set of through holes 6, respectively. The second set of through holes 6 is used for the introduction and discharge of fuel gas (water vapor in this embodiment), and the first set of through holes 5 is used for the introduction and discharge of purge gas. The first set of through holes 5 and the second set of through holes 6 are connected to the gas buffer zone 2 and the flow channel 3 on the same side, respectively.

[0024] Example 2 The connector base 1 has a square plate-like structure. Several rectangular straight ribs 4 with constant rib width are provided on its upper and lower surfaces. A flow channel 3 for gas flow is formed between adjacent rectangular straight ribs 4. The rib width of the rectangular straight ribs 4 is greater than the width of the flow channel 3 to increase the contact area between the ribs 4 and the electrodes, thereby reducing contact resistance and ohmic polarization. Gas buffer zones 2 are provided on the upper and lower surfaces of the connector base 1. A first set of through holes 5 and a second set of through holes 6 are provided on the upper and lower edges and the left and right edges of the connector 1, respectively. The second set of through holes 6 is used for the introduction and discharge of fuel gas (water vapor in this embodiment), and the first set of through holes 5 is used for the introduction and discharge of purge gas. The first set of through holes 5 and the second set of through holes 6 are connected to the gas buffer zone 2 and the flow channel 3 on the same side, respectively. On the two sides of the rectangular straight rib 4 located in the central region (non-edge position), and at the position between the two ends of the rectangular straight rib 4 along the length direction, a number of slots 7 are respectively provided at intervals along the length direction.

[0025] Example 3 The connector base 1 has a square plate-like structure. Several rectangular straight ribs 4 with constant rib width are provided on its upper and lower surfaces. A flow channel 3 for gas flow is formed between adjacent rectangular straight ribs 4. The rib width of the rectangular straight ribs 4 is greater than the width of the flow channel 3 to increase the contact area between the ribs 4 and the electrodes, thereby reducing contact resistance and ohmic polarization. Gas buffer zones 2 are provided on the upper and lower surfaces of the connector base 1. A first set of through holes 5 and a second set of through holes 6 are provided on the upper and lower edges and the left and right edges of the connector 1, respectively. The second set of through holes 6 is used for the introduction and discharge of fuel gas (water vapor in this embodiment), and the first set of through holes 5 is used for the introduction and discharge of purge gas. The first set of through holes 5 and the second set of through holes 6 are connected to the gas buffer zone 2 and the flow channel 3 on the same side, respectively. On the two sides of the rectangular straight rib 4 located in the central region (non-edge position), and at the position between the two ends of the rectangular straight rib 4 along the length direction, a number of slots 7 are respectively provided at intervals along the length direction. The slots 7 are evenly spaced on one side of the rectangular straight rib 4; the slots 7 extend inward from the side of the rectangular straight rib 4 along the rib width direction, and the depth of the slots 7 is less than the rib width of the rectangular straight rib 4, so that the slots 7 do not penetrate the rectangular straight rib 4; the height of the slots 7 is equal to the height of the rectangular straight rib 4 and is consistent with the height of the gas flow channel 3; the slots 7 on both sides of the same rectangular straight rib 4 are arranged alternately and staggered along the length of the rib 4.

[0026] Example 4 The connector base 1 has a square plate-like structure. Several rectangular straight ribs 4 with constant rib width are provided on its upper and lower surfaces. A flow channel 3 for gas flow is formed between adjacent rectangular straight ribs 4. The rib width of the rectangular straight ribs 4 is greater than the width of the flow channel 3 to increase the contact area between the ribs 4 and the electrodes, thereby reducing contact resistance and ohmic polarization. Gas buffer zones 2 are provided on the upper and lower surfaces of the connector base 1. A first set of through holes 5 and a second set of through holes 6 are provided on the upper and lower edges and the left and right edges of the connector 1, respectively. The second set of through holes 6 is used for the introduction and discharge of fuel gas (water vapor in this embodiment), and the first set of through holes 5 is used for the introduction and discharge of purge gas. The first set of through holes 5 and the second set of through holes 6 are connected to the gas buffer zone 2 and the flow channel 3 on the same side, respectively. On the two sides of the rectangular straight rib 4 located in the central region (non-edge position), and at the position between the two ends of the rectangular straight rib 4 along the length direction, a number of slots 7 are respectively provided at intervals along the length direction. The slots 7 are evenly spaced on one side of the rectangular straight rib 4; the slots 7 extend inward from the side of the rectangular straight rib 4 along the rib width direction, and the depth of the slots 7 is less than the rib width of the rectangular straight rib 4, so that the slots 7 do not penetrate the rectangular straight rib 4; the height of the slots 7 is equal to the height of the rectangular straight rib 4 and is consistent with the height of the gas flow channel 3; the slots 7 on both sides of the same rectangular straight rib 4 are arranged alternately and staggered along the length of the rib 4. The rectangular straight ribs 4 on the upper and lower surfaces of the connecting body base 1 are arranged in a staggered flow pattern, that is, the extension directions of the rectangular straight ribs 4 on the upper and lower surfaces are perpendicular to each other. The slot 7 is a rectangular slot, and its width extends along the length direction of the rib 4.

[0027] Example 5 Let's take the fuel side as an example: Water vapor flows in through the second set of through holes 6, is evenly distributed through the gas buffer zone 2, and then enters each flow channel 3. It flows along the length of the rectangular straight rib 4 in the flow channel 3. During the flow, the water vapor diffuses into the electrode below the rectangular straight rib 4 under the action of the concentration gradient. Since there are slots 7 on both sides of the rectangular straight rib 4, in addition to diffusing through the pores of the electrode itself, the water vapor can also first diffuse rapidly into the slots 7 (the diffusion speed of gas in the slots 7 is much faster than that in the porous electrode), and then diffuse from the slots 7 into the electrode area below the rectangular straight rib 4. The slots 7 provide an additional shortcut for water vapor, significantly shortening the diffusion distance, improving the gas diffusion conditions below the rectangular straight rib 4, and eliminating the low water vapor concentration area in the area under the ribs that is common in traditional structures. At the same time, since the slots 7 do not penetrate the rectangular straight rib 4, most of the contact area between the rectangular straight rib 4 and the electrode is preserved, and the current can still be smoothly conducted through the main body of the rectangular straight rib 4, and the ohmic polarization will not increase significantly.

[0028] Example 6 The working principle of the purging side is similar to that of the steam side. The purging gas flows in from the first set of through holes 5, passes through the gas buffer zone 2 and enters the air side flow channel. The flow direction is staggered with that of the fuel side, which is beneficial to the uniformity of temperature and gas distribution over a large area of ​​the entire electrolytic cell.

[0029] With the configuration of the first set of through holes 5, the second set of through holes 6 and the airflow buffer zone 2 in this invention, the gas flow rate in the flow channel 3 is uniform and the pressure difference is small. The slot 7 is not opened, which can retain the contact area between the rectangular straight rib 4 and the electrode and reduce the increase in ohmic polarization caused by the slot.

[0030] To verify the effectiveness of this improved connector design, an SOEC model using the connector design of this invention was established through numerical simulation. The calculation results are as follows: Figure 4 and Figure 5 As shown.

[0031] Figure 4 The water vapor concentration distribution at the cathode-electrolyte interface was shown. The results indicate that slot 7 effectively improves the diffusion conditions in the under-rib region, significantly increases the average water vapor concentration at the interface, and essentially eliminates the low-concentration region present in the traditional structure.

[0032] Figure 5 The distribution of current density across the cross section of the electrolyte is shown. The results indicate that although the slot 7 slightly reduces the contact area between the rib 4 and the electrode, the electrochemical reaction rate is improved due to the significant increase in water vapor concentration under the rib, and the overall electrolysis current density is still higher than that of the traditional slotless structure.

[0033] The simulation results above fully demonstrate that the present invention, through structural improvements such as alternating slots on both sides of the ribs, non-through slots, and slot height consistent with the flow channel, significantly reduces concentration polarization and eliminates the low-concentration reaction region at the cost of an acceptable increase in ohmic polarization, thereby achieving a comprehensive improvement in SOEC electrolysis performance and reaction uniformity.

[0034] The slotted rib structure solid oxide electrolytic cell connector provided by this invention has a reasonable structural design and moderate processing difficulty. It can be mass-produced using conventional machining or casting processes and is suitable for various types of solid oxide electrolytic cell stacks. It has good industrial practicality and prospects for promotion and application.

[0035] In summary, while retaining all the inherent advantages of rectangular straight-rib structures, such as low flow resistance, good airflow guidance, continuous conductive paths, and low ohmic polarization, this invention systematically solves the long-standing technical bottleneck of difficult gas diffusion under the ribs by creating alternating, staggered, non-penetrating slots 7 on both sides of the ribs, with minimal loss of conductive area and structural cost. Compared to metal foam structures, this invention avoids their inherent defects of high flow resistance, poor airflow guidance, tortuous conductive paths, and high ohmic resistance. Compared to slotting schemes that completely penetrate the ribs, this invention retains the main contact area between the ribs and the electrode and structural integrity, avoiding the problems of significantly increased ohmic polarization and decreased mechanical strength. From an electrochemical performance perspective, the slots 7 provide additional rapid diffusion channels for gas under the ribs, significantly shortening the diffusion distance of gas in the tortuous pores inside the electrode, effectively reducing concentration polarization, and eliminating the low-concentration gas region under the ribs, thus greatly improving the uniformity of the electrochemical reaction inside the electrolytic cell and the effective utilization rate of the reaction area. From a manufacturing and engineering perspective, this structure can be achieved using conventional machining, casting, or 3D printing processes. It exhibits good compatibility with existing connector production lines, low modification costs, and the depth, width, spacing, and number of slots can be flexibly optimized according to specific working conditions to achieve differentiated matching of diffusion requirements in different areas. From a system integration perspective, this connector is not only suitable for solid oxide electrolyzers but can also be directly applied to reversible solid oxide batteries, and is fully compatible with existing stack designs, facilitating technology upgrades. Furthermore, by setting the rib width to be greater than the flow channel width to further reduce ohmic polarization, by arranging the ribs on the upper and lower surfaces in a staggered flow pattern to improve the uniformity of gas distribution over a large area, and by minimizing processing costs by slotting only on the ribs at non-edge locations, these subordinate features, together with the core slotted structure, work synergistically to overcome the contradiction between the inverse relationship between ohmic polarization and concentration polarization in traditional designs, achieving a comprehensive improvement in electrolytic performance and reaction uniformity.

[0036] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A slotted rib structure connector for a solid oxide electrolytic cell, characterized in that, It includes a connector base (1); the upper and lower surfaces of the connector base (1) are respectively provided with a number of spaced rectangular straight ribs (4), and gas flow channels (3) are formed between adjacent rectangular straight ribs (4); On the two sides of at least one rectangular straight rib (4), a plurality of slots (7) are provided at intervals along the length direction; the slots (7) extend inward from the side of the rectangular straight rib (4) along the rib width direction; the depth of the slots (7) is less than the rib width of the rectangular straight rib (4), so that the slots (7) do not penetrate the rectangular straight rib (4); the slots (7) on the two sides of the same rectangular straight rib (4) are arranged alternately and staggered along the length direction of the rib (4); The upper and lower edges and the left and right edges of the connector base (1) are respectively provided with a second set of through holes (6) for fuel gas flow and a first set of through holes (5) for purging gas flow.

2. The slotted rib structure solid oxide electrolytic cell connector according to claim 1, characterized in that, The height of the slot (7) is the same as the height of the rectangular straight rib (4) and is consistent with the height of the gas flow channel (3).

3. The slotted rib structure solid oxide electrolytic cell connector according to claim 1, characterized in that, The first set of through holes (5) and the second set of through holes (6) are respectively connected to the gas flow channel (3) on the same side.

4. The slotted rib structure solid oxide electrolytic cell connector according to claim 1, characterized in that, The width of the rectangular straight rib (4) is greater than the width of the gas flow channel (3).

5. The slotted rib structure solid oxide electrolytic cell connector according to claim 1, characterized in that, The slots (7) are arranged at equal intervals on one side of the rectangular straight rib (4).

6. The slotted rib structure solid oxide electrolytic cell connector according to claim 1, characterized in that, The rectangular straight ribs (4) on the upper and lower surfaces of the connector substrate (1) are arranged in an alternating manner, that is, the extension directions of the rectangular straight ribs (4) on the upper and lower surfaces are perpendicular to each other.

7. A slotted ribbed solid oxide electrolytic cell connector according to claim 1, characterized in that, The slot (7) is a rectangular slot, and its width extends along the length of the rib (4).

8. The slotted rib structure solid oxide electrolytic cell connector according to claim 1, characterized in that, The central region of the solid oxide electrolytic cell connector with the slotted rib structure is the flow field region where the rectangular straight rib (4) is set, and the slot (7) is only set on the rectangular straight rib (4) at non-edge positions.

9. A slotted ribbed solid oxide electrolytic cell connector according to claim 1, characterized in that, The upper and lower surfaces of the connector (1) are respectively provided with gas buffers (2), and the gas buffers (2) are located between the flow channel (3) and the corresponding second set of through holes (6).

10. A solid oxide electrolytic cell stack, characterized in that, include At least two electrolytic cell plates, and at least one solid oxide electrolytic cell connector with a slotted rib structure as described in any one of claims 1 to 9; The connector is disposed between two adjacent electrolytic cell plates. The rectangular straight rib (4) on the upper surface of the connector is in contact with the cathode of one electrolytic cell plate, and the rectangular straight rib (4) on the lower surface of the connector is in contact with the anode of the other electrolytic cell plate.

Images