Single crystal electrolyte support SOC cell, SOC cell assembly, connector

Abstract

According to the novel SOC unit provided by the invention, the stable zirconium oxide single crystal is adopted as an electrolyte support body, and the electrolyte does not contain a grain boundary, so that the conductivity of oxygen ions in the electrolyte is greatly improved, the internal resistance of the electrolyte is reduced, and the electrochemical performance is excellent; and a matched SOC assembly, a connecting body and an SOC stack module are provided to guide the development of a single-crystal electrolyte supporting SOC technology and promote the development of the fields of fuel cell power generation and water electrolysis hydrogen production.

Description

Technical Field

[0001] The present invention relates to the technical field of solid oxide fuel cells (SOFCs) and solid oxide electrolyzers (SOECs), and particularly to SOC stack modules and sub-components, which are applicable to the fields of flat SOC cells, SOC cell components, interconnects, SOC stack modules, fuel cell power generation, and hydrogen production by electrolyzing water. Background Art

[0002] The Energy Law of the People's Republic of China has been implemented since January 1, 2025. Hydrogen energy has been explicitly included in the energy management system for the first time. As a clean and efficient energy form, hydrogen energy is an important cornerstone for building a future green living system. Solid oxide cells (SOCs) include solid oxide fuel cell (SOFC) technology and solid oxide electrolyzer (SOEC) technology, which are essentially reverse modes of each other and are important electrochemically energy conversion devices for hydrogen production and hydrogen utilization.

[0003] Cubic zirconia, also known as Soviet stone, exists in the form of cubic zirconia single crystals. It is an important synthetic gemstone and is widely used as a substitute for diamonds. In industrial synthesis, the "cold crucible" method is the main synthesis method. The sizes of individual crystals vary, and the largest can reach the size of a basketball, with low costs.

[0004] SOC can be classified into hydrogen electrode-supported SOC, electrolyte-supported SOC, and metal-supported SOC according to different supports. According to different ions transported by the electrolyte, it can also be classified into oxygen ion conductor SOC and proton conductor SOC. Doped zirconia electrolyte-supported SOC is of the oxygen ion conduction type. Doped zirconia powder materials are often used, and through processes such as tape casting, debinding, and sintering, a polycrystalline cubic zirconia phase structure electrolyte layer with a thickness of 100 - 300 μm and a relative density greater than 92% is synthesized. Oxygen ions need to pass through a large number of crystals, grain boundaries, and pores during conduction in the electrolyte, overcoming crystal energy barriers, grain boundary energy barriers, and spatial hindrances. The oxygen ion conductivity is often used to measure the oxygen ion conduction ability of materials. Existing literature shows that the grain boundary conductivity of doped zirconia crystals is 2 - 3 orders of magnitude lower than the crystal conductivity, and the conduction activation energy is more than 7 kJ / mol higher. Moreover, if there is segregation of impurity elements at the grain boundaries to form a second phase or multiple heterogeneous phases, the oxygen ion transport becomes more difficult and the oxygen ion conductivity is even lower. Summary of the Invention

[0005] The task of the present invention is to provide a novel single-crystal electrolyte-supported SOC cell to promote the development of the SOC field. And SOC cell components, interconnects, and SOC stack modules are provided to guide the application of the single-crystal electrolyte-supported SOC cell.

[0006] The present invention is completed through the following technical solutions: (1) Provide a single-crystal electrolyte-supported SOC unit, which includes a hydrogen electrode, an oxygen electrode, and a single-crystal electrolyte sheet disposed between the hydrogen electrode and the oxygen electrode; (2) Provide an SOC unit assembly, including a plurality of single-crystal supported SOC units and a carrier frame. The carrier frame is provided with a groove portion, a gas flow channel, an air inlet hole, an air outlet hole, a positioning hole, a bolt hole, a cavity, and a mechanical support portion; (3) Provide a connector, which is provided with an electrode current collector material mounting groove, a through hole in the groove, a conductive material filled in the through hole, a gas flow channel, an air inlet hole, an air outlet hole, a positioning hole, a bolt hole, a cavity, and a mechanical support portion; (4) Provide an SOC stack module, which is stacked by a plurality of stack repeating units and includes an SOC unit assembly, a connector, a current collector material, and a sealing material.

[0007] Compared with the prior art, the present invention has the following advantages or effects: The present invention provides an SOC unit, which uses stabilized zirconia single crystal as the electrolyte support, adding a new type of SOC support; because the electrolyte does not contain grain boundaries, it greatly improves the conduction ability of oxygen ions in the electrolyte, reduces the internal resistance of the electrolyte, and has excellent electrochemical performance; and provides corresponding SOC components, connectors, and stack modules to promote its development in the fields of fuel cell power generation and electrolytic water hydrogen production; at the same time, the application of the stabilized zirconia single-crystal electrolyte-supported SOC unit also broadens the application field of cubic zirconia and improves the added value level of cubic zirconia. Description of the Drawings

[0008] Figure 1 A cross-sectional view showing an embodiment of the single-crystal electrolyte-supported SOC unit of the present invention.

[0009] Figure 2 A schematic structural diagram showing an embodiment 100A of the SOC unit assembly of the present invention.

[0010] Figure 3 A cross-sectional view showing an embodiment 120a of the groove portion of the SOC unit assembly of the present invention.

[0011] Figure 4 A cross-sectional view showing an embodiment 120b of the groove portion of the SOC unit assembly of the present invention.

[0012] Figure 5 A schematic structural diagram showing an embodiment 100B of the SOC unit assembly of the present invention.

[0013] Figure 6 A schematic structural diagram showing an embodiment 100C of the SOC unit assembly of the present invention.

[0014] Figure 7 A schematic structural diagram showing an embodiment 100D of the SOC unit assembly of the present invention.

[0015] Figure 8 Schematic structural diagram showing an embodiment 300A of the connector of the present invention.

[0016] Figure 9 Schematic structural diagram showing an embodiment 300B of the connector of the present invention.

[0017] Figure 10 Schematic structural diagram showing an embodiment 300C of the connector of the present invention.

[0018] Figure 11 Schematic structural diagram showing an embodiment 300D of the connector of the present invention.

[0019] Figure 12 Schematic structural diagram showing an embodiment 300E of the connector of the present invention.

[0020] Figure 13 Schematic structural diagram showing an embodiment 300F of the connector of the present invention.

[0021] Figure 14 Schematic stacking structure diagram showing an embodiment of the repeating unit of the SOC stack module of the present invention.

[0022] Each numerical identifier in the drawings respectively represents: 100. SOC unit assembly; 110. Single crystal electrolyte supported SOC unit; 111. Single crystal electrolyte sheet; 112. Oxygen electrode; 113. Hydrogen electrode; 120. Groove part of the SOC unit assembly; 121. Cavity; 122. SOC unit mounting groove; 123. Electrode current collector material mounting groove 1; 124. Electrode current collector material mounting groove 2; 130. Inlet / outlet port; 140. Gas flow channel; 200. Sealing material; 300. Connector; 310. Electrode current collector material mounting groove; 320. Through hole in the groove; 330. Inlet / outlet air hole; 340. Gas flow channel. Detailed implementation mode

[0023] The first aspect of the present invention provides a single crystal electrolyte supported SOC unit, comprising a hydrogen electrode, an oxygen electrode, and a single crystal electrolyte sheet disposed between the hydrogen electrode and the oxygen electrode.

[0024] The single crystal electrolyte sheet comprises an electrolyte component, has a thickness of 50 - 300 μm, and the projected shape of the electrolyte surface perpendicular to the thickness direction is a regular shape, including a square, a rectangle, and a circle.

[0025] The electrolyte component is composed of a yttrium oxide or scandium oxide stabilized zirconia-based oxide, and the proportion of yttrium oxide or scandium oxide is between 6 - 18 mol%.

[0026] The second aspect of the present invention provides an SOC unit assembly, which is a flat structure with a thickness of 0.2 to 5 mm and includes a plurality of SOC units and a frame for carrying the SOC units.

[0027] The material of the frame for carrying the SOC units is any one of ferrochromium alloy, high-chromium ferritic stainless steel (chromium mass fraction between 12% and 30%), yttrium-stabilized zirconia ceramic, magnesium-stabilized zirconia ceramic, zirconia toughened alumina ceramic, zirconia toughened mullite ceramic, and glass-ceramics.

[0028] The frame for carrying the SOC units is provided with a groove part, a gas flow channel, an air inlet hole, an air outlet hole, a positioning hole, a bolt hole, a cavity, and a mechanical support part.

[0029] The grooves are distributed in an array on the SOC unit assembly. The groove is provided with an SOC unit installation groove, an electrode current collector material installation groove, and a cavity for exposing the active part of the SOC unit. The depth of the SOC unit installation groove is 0.05 to 2 mm, and the depth of the electrode current collector material installation groove is 0 to 1 mm.

[0030] The gas flow channels are distributed in an array on the SOC unit assembly, with a depth of 0 to 1.5 mm and a width of 0 to 50 mm.

[0031] The shapes, numbers, and positions of the air inlet hole, the air outlet hole, the positioning hole, the bolt hole, and the mechanical support part are not specifically restricted, as long as it is beneficial for assembly and gas diffusion.

[0032] In some embodiments, the SOC unit assembly is a flat circle, and the SOC units and the groove part are distributed in an annular array. Each groove contains 2 electrode current collector material installation grooves, which are symmetrically distributed above and below the flat circle.

[0033] In some embodiments, the SOC unit assembly is a flat ring, and there is a cavity in the middle for placing the inlet and exhaust pipes and the external circuit wires. The SOC units and the groove part are distributed in an annular array, and each groove contains 1 electrode current collector material installation groove.

[0034] In some embodiments, the SOC unit assembly is a flat square, and the SOC units, the groove part, and the gas flow channels are distributed in a grid array. Each groove contains 2 electrode current collector material installation grooves, which are symmetrically distributed above and below the flat circle.

[0035] In some embodiments, the SOC unit assembly is a flat square, and there is a cavity in the middle for placing the inlet and exhaust pipes and the external circuit wires. The SOC units and the groove part are distributed in a grid array, and there is no gas flow channel.

[0036] The third aspect of the present invention provides a connector, which is a flat plate structure with a thickness of 0.5 to 5 mm, and is provided with an electrode current collector material installation groove, a through hole in the groove, a conductive material filling the through hole, a gas flow channel, an air inlet hole, an air outlet hole, a positioning hole, a bolt hole, a cavity and a mechanical support part.

[0037] The material of the connector is any one of ferritic chromium alloy, high-chromium ferritic stainless steel (chromium mass fraction between 12% and 30%), yttrium-stabilized zirconia ceramic, magnesium-stabilized zirconia ceramic, zirconia toughened alumina ceramic, zirconia toughened mullite ceramic, and glass-ceramics.

[0038] The electrode current collector material installation grooves are arranged in an array on the connector, with a groove depth of 0 to 1 mm. The cross-sectional shape of the through hole in the groove in the thickness direction can be selected from a rectangle, a square, a trapezoid or a combination of the above three shapes, and the cross-sectional area of a single through hole is between 0 and 50 mm 2 , and the filling conductive material can be selected from ferritic chromium alloy, high-chromium ferritic stainless steel (chromium mass fraction between 12% and 30%), metallic nickel, nickel-iron alloy, metallic copper, metallic silver, metallic platinum, LnBaCo2O 5+δ (Ln = Pr, La, Gd, Sm, Nd, Y), La2Ni x Cu 1- x O 4+δ , La2NiO 4+δ , Pr2NiO 4+δ , Nd2NiO 4+δ , Cu 1.3 Mn 1.7 O4 spinel structure materials and at least one or more combinations of perovskite-type conductive materials. The molecular general formula of the perovskite-type conductive material is ABO3, and the A-site elements include one or more of lanthanum, praseodymium, strontium, barium, calcium, and magnesium, and the B-site elements include one or more of manganese, iron, cobalt, nickel, molybdenum, niobium, chromium, and copper.

[0039] The gas flow channels are arranged in an array on the connector, with a depth of 0 to 1.5 mm and a width of 0 to 50 mm.

[0040] The shapes, numbers and positions of the air inlet hole, the air outlet hole, the positioning hole, the bolt hole and the mechanical support part are not specifically restricted, as long as it is beneficial to assembly and gas diffusion.

[0041] In some embodiments, the connector is a flat plate ring, made of SUS441 stainless steel, with a cavity for placing the intake and exhaust pipes and the external circuit wires in the middle, and there is no electrode current collector material installation groove, through hole in the groove and gas flow channel.

[0042] In some embodiments, the connector is a flat plate square, made of Crofer22 stainless steel, and the gas flow channels are distributed in a grid array, and there is no electrode current collector material installation groove.

[0043] In some embodiments, the connector is a flat square made of glass-ceramics. The electrode current collector material mounting grooves, the through holes in the grooves, and the gas flow channel grid are distributed in an array. The cross-sectional shape of the through holes in the grooves in the thickness direction is trapezoidal, and the conductive material filled is SUS444 stainless steel.

[0044] The fourth aspect of the present invention provides an SOC stack module, which is stacked by a plurality of stack repeating units and includes at least one SOC unit component provided in the second aspect and at least one connector provided in the third aspect.

[0045] The stack repeating unit is formed by sequentially stacking a connector, a sealing material, a current collector material, an SOC unit component, a current collector material, a sealing material, and a connector.

[0046] To more clearly illustrate the solution of the present application, a kind of SOC unit, SOC unit component, connector, and SOC stack module applicable in the present application will be briefly described below. Embodiment

[0047] Referring to Figure 14 , the stack repeating unit of the SOC stack module includes one SOC unit component 100, two sealing material parts 200, two connector parts 300, 9 hydrogen electrode current collector parts, and 9 oxygen electrode current collector parts.

[0048] Referring to Figure 2 , the SOC unit component selects a flat square 100A, which includes 9 single-crystal electrolyte-supported SOC units 110 distributed in an array, 9 SOC unit component groove parts 120, 12 inlets / outlets 130, and 6 gas flow channels (3 on the other side in the thickness direction). The thickness of the carrier frame is 2 mm and the material is glass-ceramics. Among them, the SOC unit 110 has a three-layer structure, including an electrolyte sheet 111, an oxygen electrode 112, and a hydrogen electrode 113. The projection shape of the electrolyte in the thickness direction is circular, the electrolyte thickness is 200 ± 10 μm, and the electrolyte material is 13 mol% yttria-stabilized zirconia single crystal. Referring to Figure 1 ; the groove part 120 includes one cavity 121, one SOC unit mounting groove 122, and two electrode current collector material mounting grooves 123 / 124. The depth of the SOC unit mounting groove is 0.3 mm, and the depth of the electrode current collector material mounting groove is 0.15 mm; the depth of the gas flow channel is 0.2 mm and the width is 10 mm. Referring to Figure 3 .

[0049] Referring to Figure 8, the connecting body is selected as a flat square 300A with a thickness of 2 mm, and the material is glass-ceramics. It includes 9 electrode current collector material installation grooves 310, 9 through holes 320 in the grooves, 12 air inlet / outlet holes 330 and 3 gas flow channels 340. Among them, the depth of the electrode current collector material installation groove is 0.15 mm; the cross-sectional shape of the through hole in the groove in the thickness direction is square, and the conductive material filled in the through hole in the groove is Crofer22 stainless steel; the depth of the gas flow channel is 0.2 mm and the width is 10 mm.

[0050] As described above, the present invention can be preferably realized. The above embodiments are only some embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall all be equivalent substitution methods and are included in the protection scope of the present invention.

Claims

1. A single-crystal electrolyte-supported SOC cell, characterized in that, It includes a hydrogen electrode, an oxygen electrode, and a single-crystal electrolyte sheet disposed between the hydrogen electrode and the oxygen electrode.

2. The single-crystal electrolyte-supported SOC unit according to claim 1, wherein The single-crystal electrolyte sheet contains an electrolyte component, has a thickness of 50 - 300 μm, and the projected shape of the electrolyte surface perpendicular to the thickness direction is a regular shape, including square, rectangle, and circle. The electrolyte component is composed of a yttria- or scandia-stabilized zirconia-based oxide, and the proportion of yttria or scandia is between 6 - 18 mol%.

3. The SOC unit component, characterized in that, It includes an SOC unit and a frame for carrying the SOC unit. The component has a flat structure and a thickness of 0.2 - 5 mm.

4. The SOC unit component according to claim 3, wherein The material of the frame for carrying the SOC unit is any one of ferritic chromium alloy, high-chromium ferritic stainless steel (chromium mass fraction between 12 - 30%), yttria-stabilized zirconia ceramic, magnesia-stabilized zirconia ceramic, zirconia toughened alumina ceramic, zirconia toughened mullite ceramic, and glass-ceramic.

5. The SOC unit component according to claim 3, wherein The frame for carrying the SOC unit is provided with a groove part, a gas flow channel, an air inlet hole, an air outlet hole, a positioning hole, a bolt hole, a cavity, and a mechanical support part, where: The grooves are arrayed on the SOC unit component. The groove is provided with an SOC unit installation groove, an electrode current collector material installation groove, and a cavity for exposing the active part of the SOC unit. The depth of the SOC unit installation groove is 0.05 - 2 mm, and the depth of the electrode current collector material installation groove is 0 - 1 mm. The gas flow channels are arrayed on the SOC unit component, with a depth of 0 - 1.5 mm and a width of 0 - 50 mm.

6. Connecting body, characterized in that, It is provided with an electrode current collector material installation groove, a through hole in the groove, a conductive material filled in the through hole, a gas flow channel, an air inlet hole, an air outlet hole, a positioning hole, a bolt hole, a cavity, and a mechanical support part. The connector has a flat structure, a thickness of 0.5 - 5 mm, and the material is any one of ferritic chromium alloy, high-chromium ferritic stainless steel (chromium mass fraction between 12 - 30%), yttria-stabilized zirconia ceramic, magnesia-stabilized zirconia ceramic, zirconia toughened alumina ceramic, zirconia toughened mullite ceramic, and glass-ceramic.

7. The connector according to claim 6, characterized in that The electrode current collector material mounting groove arrays are distributed on the connector, the groove depth is 0 - 1 mm, the cross-sectional shape of the through hole in the groove in the thickness direction can be rectangular, square, trapezoidal or a combination of the above three shapes, and the cross-sectional area of a single through hole is between 0 - 50 mm 2 , and the gas flow channel arrays are distributed on the connector, with a depth of 0 - 1.5 mm and a width of 0 - 50 mm.

8. The connector according to claim 6, wherein The filling conductive material may be one or more of ferrochromium alloy, high-chromium ferritic stainless steel (chromium mass fraction between 12% and 30%), metallic nickel, nickel-iron alloy, metallic copper, metallic silver, metallic platinum, LnBaCo2O 5+δ (Ln = Pr, La, Gd, Sm, Nd, Y), La2Ni x Cu 1-x O 4+δ , La2NiO 4+δ , Pr2NiO 4+δ , Nd2NiO 4+δ , Cu 1.3 Mn 1.7 O4 spinel structure material and at least one or more combinations of perovskite-type conductive materials. The molecular general formula of the perovskite-type conductive material is ABO3, and the A-site elements include one or more of lanthanum, praseodymium, strontium, barium, calcium, and magnesium, and the B-site elements include one or more of manganese, iron, cobalt, nickel, molybdenum, niobium, chromium, and copper.

9. The SOC stack module is characterized in that, It is stacked by a plurality of stack repeat units, including at least one SOC unit component as described in claim 3 and at least one connector as described in claim 6. Among them, the stack repeat unit is stacked in sequence by a connector, a sealing material, a current collector material, an SOC unit component, a current collector material, a sealing material, and a connector.

10. A component and system constituted by any combination of the technical features described in claims 1, 3, 6, and 9.

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