Symmetrical sealing method for solid oxide electrolysis cells

Abstract

The present application relates to the technical field of solid oxide electrolysis cell, and particularly relates to a symmetrical sealing method of solid oxide electrolysis cell. The method is to seal the four edges of a single solid oxide electrolysis cell on a cell frame, and the cell frames on the two sides of the single solid oxide electrolysis cell are symmetrically arranged, and the single solid oxide electrolysis cell and the cell frame are sealed by a sealant to form a single cell unit. The present application forms symmetrical stress on the upper and lower surfaces of the ceramic electrolysis single cell, and can effectively alleviate the problem of stress concentration caused by single-sided sealing. Due to the protection of the cell frame, the electrolysis single cell will not be damaged when the pressure is applied during the assembly of the stack, thereby ensuring the safety and reliability of the stack.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of solid oxide electrolysis cell technology, and particularly relates to a symmetrical sealing method for solid oxide electrolysis cell. BACKGROUND

[0002] The solid oxide electrolysis cell (SOEC) is an energy conversion device that converts electrical energy into chemical energy, and has the advantages of being clean and efficient.

[0003] The SOEC mainly has two structural forms of tube type and flat plate type. Since the voltage and power provided by a single electrolysis cell are very limited, in order to meet the use requirements, multiple single cells need to be assembled into a cell stack in various ways (series, parallel, and mixed connection). Compared with the tube type structure, the flat plate type structure has the advantages of short current flow path, small ohmic loss, and high energy density. However, the main disadvantage of the flat plate type structure is that high-temperature sealing is difficult, which is one of the technical difficulties limiting its development.

[0004] Glass and glass-ceramics are the most widely studied and applied sealing materials. Compared with other forms of sealing materials such as flexible metal, mica substrate, and metal brazing, glass has the advantages of good high-temperature sealing performance, adjustable coefficient of thermal expansion (CTE), and easy preparation and use. The most commonly used sealing method is to pre-seal the electrolysis single cell to the cell frame with a glass sealant before the assembly of the cell stack, and then seal the cell frame and the metal bipolar plate during the assembly of the cell stack. This sealing scheme first heats to a temperature (T s ) above the softening temperature of the glass to ensure the softening and flow of the glass to infiltrate the sealing part, and then cools to a temperature (T s ) below the solidification temperature to solidify. However, when the temperature decreases, the mismatch between the coefficients of thermal expansion of the electrolysis cell material, the sealing glass, and the metal bipolar plate causes stress at the sealing interface, especially during the subsequent cell stack assembly and pressurization operation, the edges of the electrolysis single cell made of ceramic material are prone to cracking, and in severe cases, the entire cell may even be broken. Therefore, seeking a simple and reliable sealing scheme to effectively alleviate the stress concentration in the sealing area of the electrolysis cell is a problem that needs to be solved by those skilled in the art. SUMMARY

[0005] In view of the above problems, the purpose of the present application is to provide a symmetrical sealing method for solid oxide electrolysis cell to overcome the stress concentration problem in the sealing process of the prior art and improve the sealing performance of the electrolysis cell.

[0006] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0007] The application provides a solid oxide electrolysis cell symmetrical sealing method, which seals the four edges of a single cell of a solid oxide electrolysis cell on a cell frame, and the cell frames on the two sides of the single cell are symmetrically arranged, the single cell and the cell frame are sealed by a sealing agent, and a single cell unit is formed.

[0008] The cell frame is provided with a mounting groove, the solid oxide electrolysis cell single cell is arranged in the mounting groove of the cell frame, and the solid oxide electrolysis cell single cell can expose the entire area of the electrode.

[0009] The solid oxide electrolysis cell single cell comprises a first electrode of an electrolysis single cell, a second electrode of an electrolysis single cell arranged in parallel, and an electrolyte of an electrolysis single cell arranged between the first electrode and the second electrode.

[0010] The cell frame is made of metal.

[0011] The cell frame is provided with a hole corresponding to the gas inlet and outlet channel of the solid oxide electrolysis cell single cell.

[0012] The cell frame comprises an upper cell frame and a lower cell frame, and the solid oxide electrolysis cell single cell is arranged between the upper cell frame and the lower cell frame.

[0013] The upper cell frame and the lower cell frame are of the same structure and are provided with embedding grooves; the embedding grooves of the upper cell frame and the lower cell frame are coated with a sealing agent, and the solid oxide electrolysis cell single cell is embedded in the embedding grooves of the upper cell frame and the lower cell frame to form a symmetrical structure of the upper cell frame-sealing agent-solid oxide electrolysis cell single cell-sealing agent-lower cell frame.

[0014] The lower cell frame is provided with an embedding groove, the solid oxide electrolysis cell single cell is embedded in the embedding groove of the lower cell frame, the upper cell frame is a flat frame structure and is arranged above the lower cell frame, and the thicknesses of the upper cell frame and the lower cell frame on the two sides of the solid oxide electrolysis cell single cell are equal.

[0015] Three side frames of the lower cell frame are provided with insertion grooves, the solid oxide electrolysis cell single cell is inserted into the insertion grooves of the three side frames of the lower cell frame, the upper cell frame is a strip-shaped plate and is arranged on a side frame of the lower cell frame without an insertion groove to fix the solid oxide electrolysis cell single cell.

[0016] The sealing agent is a high-temperature-resistant sealing agent capable of resisting 400-1000 DEG C.

[0017] The application has the following advantages and beneficial effects:

[0018] 1. The present application adopts solid sealing method to seal the electrolytic single cell to the battery frame to form a single cell unit, and presents a symmetrical structure of battery frame-sealant-electrolytic single cell-sealant-battery frame in the sealing area, forms symmetrical stress on the upper and lower surfaces of the ceramic electrolytic single cell, and can effectively alleviate the stress concentration problem caused by single sealing.

[0019] 2. The ceramic electrolytic single cell is completely wrapped in the metal battery frame, and the single cell is protected, and when pressure is applied in the subsequent stack assembly process, the pressure acts on the battery frames on both sides, and the electrolytic single cell will not be damaged. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a sealing area schematic diagram of embodiment 1 of the present application;

[0021] Figure 2 is a cooperation schematic diagram of the battery frame and the solid oxide electrolytic cell single cell of embodiment 1 of the present application;

[0022] Figure 3 is a sealing area schematic diagram of embodiment 2 of the present application;

[0023] Figure 4 is a cooperation schematic diagram of the battery frame and the solid oxide electrolytic cell single cell of embodiment 2 of the present application;

[0024] Figure 5 is a sealing area schematic diagram of embodiment 3 of the present application;

[0025] Figure 6 is a cooperation schematic diagram of the battery frame and the solid oxide electrolytic cell single cell of embodiment 3 of the present application;

[0026] Figure 7 is a top view of the lower part of the battery frame of embodiment 3 of the present application;

[0027] Figure 8 is an A-A partial sectional view of the lower part of the battery frame of embodiment 3 of the present application;

[0028] In the figure: 1-solid oxide electrolytic cell single cell, 2-electrolytic single cell first electrode, 3-electrolytic single cell electrolyte, 4-electrolytic single cell second electrode, 5-battery frame, 5(a)-upper part of the battery frame, 5(b)-lower part of the battery frame, 6-sealant. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application will be described in detail below with reference to the drawings and specific embodiments.

[0030] As Figures 1-2As shown, the present application provides a solid oxide electrolysis cell symmetrical sealing method, the four peripheral edges of a solid oxide electrolysis cell single cell 1 are packaged on a cell frame 5 by solid sealing, and the cell frames 5 on both sides of the solid oxide electrolysis cell single cell 1 are symmetrically arranged, and the solid oxide electrolysis cell single cell 1 and the cell frame 5 are sealed by a sealant 6 to form a single cell unit. The sealing area is symmetrically arranged from top to bottom as cell frame, sealant, electrolysis cell single cell, sealant, and cell frame. The solid oxide electrolysis cell single cell 1 is completely wrapped in the cell frame 5, which protects the single cell unit, and when pressure is applied in the subsequent stack assembly process, the pressure acts on the cell frames on both sides, and the electrolysis single cell will not be damaged.

[0031] In an embodiment of the present application, the cell frame 5 is provided with a mounting groove, and the solid oxide electrolysis cell single cell 1 is arranged in the mounting groove of the cell frame 5, and the solid oxide electrolysis cell single cell 1 can expose the entire area of the electrode.

[0032] Specifically, the solid oxide electrolysis cell single cell 1 includes a parallelly arranged electrolysis cell first electrode 2 and an electrolysis cell second electrode 4, and an electrolysis cell electrolyte arranged between the electrolysis cell first electrode 2 and the electrolysis cell second electrode 4.

[0033] In an embodiment of the present application, the cell frame 5 is made of metal material. Specifically, the base material of the cell frame 5 is one or more than two of Fe-based or Ni-based heat-resistant alloy.

[0034] Further, the cell frame 5 is provided with holes corresponding to the gas inlet and outlet channels of the solid oxide electrolysis cell single cell 1.

[0035] In an embodiment of the present application, the sealant 6 is a high-temperature-resistant sealant that can withstand 400-1000℃, and the base material can be glass, glass-ceramic, silicate, high-temperature-resistant oxide, etc. In the sealing process, according to the different sealants 6 used, it can be realized at room temperature, or it can be realized by increasing the temperature, and the sealing process does not need to be pressurized.

[0036] In an embodiment of the present application, the cell frame 5 includes a cell frame upper part 5(a) and a cell frame lower part 5(b), and the solid oxide electrolysis cell single cell 1 is arranged between the cell frame upper part 5(a) and the cell frame lower part 5(b), and the shapes of the cell frame upper part 5(a) and the cell frame lower part 5(b) can be the same or different.

[0037] Embodiment 1

[0038] As Figures 1-2As shown, in this embodiment, the upper part 5(a) and the lower part 5(b) of the battery frame have the same structure, and their opposite surfaces are provided with grooves. A sealant 6 is applied to the grooves of the upper part 5(a) and the lower part 5(b) of the battery frame. The solid oxide electrolytic cell 1 is embedded in the grooves of the upper part 5(a) and the lower part 5(b) of the battery frame, thereby forming a symmetrical structure of upper part 5(a)-sealant 6-solid oxide electrolytic cell 1-sealant 6-lower part 5(b) of the battery frame, and exposing the entire area of ​​the first electrode 2 of the electrolytic cell.

[0039] Specifically, both the upper part 5(a) and the lower part 5(b) of the battery frame are made of Fe-based heat-resistant alloy. The sealant 6 used is based on glass and can withstand high temperatures of 800℃.

[0040] The specific sealing process is as follows:

[0041] A glass sealant is applied to the sealing area within the groove of the lower part 5(b) of the battery frame. A solid oxide electrolytic cell 1 is placed on the lower part 5(b). A glass sealant is then applied to the sealing area within the groove of the upper part 5(a) of the battery frame. The upper part 5(a) and the lower part 5(b) of the battery frame are then joined together, and the temperature is raised to 780℃ for high-temperature sealing. The sealing area, from top to bottom, consists of the battery frame, sealant, electrolytic cell, sealant, and battery frame, presenting a symmetrical structure of battery frame-sealant-electrolytic cell-sealant-battery frame, effectively alleviating uneven stress on both sides of the solid oxide electrolytic cell 1. Furthermore, due to the protection of the upper and lower parts of the metal battery frame, the solid oxide electrolytic cell 1 is not subjected to pressure during the stack assembly process, thus preventing damage.

[0042] Example 2

[0043] like Figures 3-4 As shown, in this embodiment, the lower part 5(b) of the battery frame has a groove, and the upper part 5(a) of the battery frame has a flat frame structure. Both the upper part 5(a) and the lower part 5(b) of the battery frame are made of Ni-based heat-resistant alloy. The solid oxide electrolytic cell 1 is embedded in the groove of the lower part 5(b) of the battery frame, and the upper part 5(a) of the battery frame is located above the lower part 5(b). The thickness of the upper part 5(a) and the lower part 5(b) of the battery frame on both sides of the solid oxide electrolytic cell 1 is equal, and the solid oxide electrolytic cell 1 exposes the entire area of ​​the first electrode 2 of the electrolytic cell. In addition, the lower part 5(b) of the battery frame also has holes corresponding to the gas inlet and outlet channels of the electrolytic cell. The sealant 6 used is based on silicate and can withstand a high temperature of 1080°C.

[0044] The specific sealing process is as follows:

[0045] Apply glass sealant to the groove to be sealed in the lower part 5(b) of the battery frame. Place a solid oxide electrolytic cell 1 in the groove in the lower part 5(b) of the battery frame. Apply glass sealant to the groove to be sealed in the upper part 5(a) of the battery frame. Combine the upper part 5(a) and the lower part 5(b) of the battery frame and dry at room temperature to complete the sealing.

[0046] Example 3

[0047] like Figures 5-8 As shown, in this embodiment, the lower part 5(b) of the battery frame has slots on three sides, the upper part 5(a) of the battery frame is slatted, and both the upper part 5(a) and the lower part 5(b) of the battery frame are made of Fe-based heat-resistant alloy. The sealant 6 is a glass-based sealant. The solid oxide electrolytic cell 1 is inserted into the slots on the three sides of the lower part 5(b) of the battery frame; the upper part 5(a) of the battery frame is located on the side of the lower part 5(b) of the battery frame without slots, for fixing the solid oxide electrolytic cell 1.

[0048] The specific sealing process is as follows:

[0049] A glass-based sealant is applied to the slots on the three sides of the lower part 5(b) of the battery frame. The solid oxide electrolytic cell 1 is inserted from one end into the slots on the three sides of the lower part 5(b) of the battery frame. Then, the upper part 5(a) of the battery frame coated with glass sealant is placed in the corresponding area, that is, on the side of the lower part 5(b) of the battery frame without slots. The temperature is raised to 780°C for high-temperature sealing.

[0050] This invention employs a solid-sealing method to seal individual electrolytic cells onto a battery frame to form a single-cell unit. The sealing area exhibits a symmetrical structure of battery frame-sealant-electrolytic cell-sealant-battery frame, creating symmetrical stress on both the upper and lower surfaces of the ceramic electrolytic cell. This effectively alleviates the stress concentration problem caused by single-sided sealing. The ceramic electrolytic cell is completely enclosed within the metal battery frame, providing protection for the cell. During subsequent stack assembly, when pressure is applied, the pressure acts on the battery frames on both sides, preventing damage to the electrolytic cell and thus ensuring the safety and reliability of the stack.

[0051] The above description is merely an embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, extensions, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A method of sealing a solid oxide electrolysis cell symmetrically, characterized in that, The four peripheral edges of the solid oxide electrolysis cell single cell are packaged on the cell frame, and the cell frames on both sides of the solid oxide electrolysis cell single cell are symmetrically arranged, the solid oxide electrolysis cell single cell and the cell frame are sealed by a sealing agent, and a single cell unit is formed; The cell frame is provided with a mounting groove, the solid oxide electrolysis cell single cell is arranged in the mounting groove of the cell frame, and the solid oxide electrolysis cell single cell can expose the whole area of the electrode; The solid oxide electrolysis cell single cell comprises a first electrolysis cell electrode and a second electrolysis cell electrode arranged in parallel and an electrolyte arranged between the first electrolysis cell electrode and the second electrolysis cell electrode; The cell frame is made of metal material; the cell frame is provided with holes corresponding to the gas inlet and outlet channels of the solid oxide electrolysis cell single cell; The sealant is a high-temperature resistant sealant capable of withstanding 400 to 1000 o C. The cell frame comprises a cell frame upper part and a cell frame lower part, and the solid oxide electrolysis cell single cell is arranged between the cell frame upper part and the cell frame lower part; The cell frame upper part and the cell frame lower part have the same structure and are provided with embedding grooves; the embedding grooves of the cell frame upper part and the cell frame lower part are coated with a sealing agent, and the solid oxide electrolysis cell single cell is embedded in the embedding grooves of the cell frame upper part and the cell frame lower part to form a symmetric structure of cell frame upper part-sealing agent-solid oxide electrolysis cell single cell-sealing agent-cell frame lower part; Or, the cell frame lower part is provided with an embedding groove, the solid oxide electrolysis cell single cell is embedded in the embedding groove of the cell frame lower part, the cell frame upper part is a flat frame structure and is arranged above the cell frame lower part, and the thickness of the cell frame upper part on both sides of the solid oxide electrolysis cell single cell and the cell frame lower part is equal; Or, three side frames of the cell frame lower part are provided with insertion grooves, the solid oxide electrolysis cell single cell is inserted into the insertion grooves of the three side frames of the cell frame lower part; the cell frame upper part is a batten and is arranged on the frame without the insertion groove of the cell frame lower part to fix the solid oxide electrolysis cell single cell.

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