Ceramic-based salt battery multi-component integrated sealing method

Abstract

The invention discloses a ceramic-based salt battery multi-component integrated sealing method, and relates to the technical field of new energy, and sealing components comprise a Na-beta-Al2O3 ceramic tube, first glass, a first alloy, an insulating alpha-Al2O3 ceramic ring, second glass, a second alloy and a positioning tool. The invention relates to an integrated sealing method for multiple components of a ceramic-based salt battery, and designs an integrated sealing method for multiple components of a ceramic tube related to a sodium salt battery. And the safety risk caused by the technical complexity and inconsistency of battery equipment due to step-by-step sealing of an insulating ceramic ring and stainless steel metal is avoided, and the whole method has the characteristics of low cost, simplicity in operation, easiness in industrialization, no need of large-scale equipment and the like, and adopts a glass system of a borosilicic acid system as a glass sealing material; the catalyst has good chemical stability, and is resistant to alkali steam and sulfur steam erosion.

Description

Technical Field

[0001] The invention relates to the field of new energy technology, and in particular to a multi-component integrated sealing method for a ceramic-based salt battery. Background Art

[0002] Sodium batteries with ceramic-based solid electrolytes are represented by sodium salt batteries and sodium sulfur batteries, with Na-beta-Al 2 O 3 Solid electrolyte ceramics are solid electrolytes. Na ions shuttle through the electrolyte to form electronic conduction in the external circuit to achieve battery charging and discharging. The sealing of the solid electrolyte and related components is the key to ensuring the assembly and long-life operation of this type of battery.

[0003] Taking sodium salt batteries as an example, sodium salt batteries use metallic sodium as the negative electrode and sodium chloride and other materials as the positive electrode. It is one of the few safe batteries that are not prone to combustion and explosion hazards. It has the advantages of high specific energy and high safety, and can be called high specific energy and near-zero hidden danger energy storage batteries. In view of the above advantages, sodium salt batteries have a wide range of applications, such as the storage of renewable energy power generation such as wind power and solar energy, peak shaving and valley filling, distributed energy storage systems, electric vehicles, communication base stations, etc. During the assembly and preparation process of sodium salt batteries, the positive and negative electrodes of the battery are in contact with multiple components at the same time. These components need to be combined through a high-performance sealing system to achieve safe operation and cycle life of the battery.

[0004] This type of ceramic-based sodium battery is composed of multiple components that are sealed together. In order to ensure the safety of the battery, a high-performance sealing system is essential to ensure the safe operation of the battery. Strict isolation between the positive and negative electrode working chambers of the battery is very important. There are multiple components that are in contact with the positive and negative electrodes of the battery at the same time. These components are combined together through various materials and technologies. In the design of most sodium batteries, electrically insulating alpha-Al 2 O 3 As an insulating layer for electrons and ions between the positive and negative electrodes, it also serves to strengthen the Na-beta-Al 2 O 3 The top of the solid electrolyte ceramic tube is then connected to the metal current collector and the annular alpha-Al 2 O 3The joints are sealed, and finally, the outermost metals are sealed to form a fully sealed sodium battery. The sealing structure of the battery has a great influence on the design of the battery and the electrochemical performance of the battery during use. For example, the seal will affect the battery's potential, limit the maximum temperature and pressure of the battery, and the specific energy of the battery. The fully sealed structure of the sodium salt battery includes three categories: metal-to-metal sealing, metal-to-ceramic sealing, and ceramic-to-ceramic sealing. Usually different components use different sealing processes. Currently, the commonly used sealing bonding methods include mechanical sealing, adhesive sealing, metal spraying, cold pressing sealing, solid phase or molten state bonding, hot pressing sealing bonding, etc. This makes the sodium salt battery preparation process cumbersome and the inconsistency of sealing performance lead to the risk of battery failure.

[0005] The metal-to-metal sealing is achieved by sealing the stainless steel tube and the stainless steel cap, as well as the positive electrode current collector and the sealing alloy and the top cover, using traditional laser welding.

[0006] The sealing of metal and ceramic is the sealing between the insulating ceramic joint and the stainless steel metal. It is the most difficult and critical process link because the expansion coefficients of the two are the largest and difficult to match. The commonly used sealing methods include mechanical sealing, adhesive sealing, metal spraying, cold pressing sealing, solid phase or molten state bonding, hot pressing sealing bonding, etc.

[0007] The sealing between ceramics refers to the sealing between the insulating ceramic ring and the solid electrolyte ceramic tube. Due to the physical properties of ceramic materials such as chemical inertness, low diffusion and high melting point, the sealing between ceramics is also relatively difficult. Similar to the sealing between metals and ceramics, the main sealing methods currently include brazing, reaction sintering connection, microwave connection and glass sealing.

[0008] The sealing structure of sodium salt batteries has a great influence on the design and electrochemical performance of the battery. For example, the seal will affect the battery's potential, limit the battery's maximum operating temperature, pressure and specific energy, etc. If the seal is not well combined, serious safety problems such as internal short circuits may even occur.

[0009] Therefore, designing a high-performance sealing system is crucial to ensure battery safety and cycle performance. Summary of the invention

[0010] The main purpose of the present invention is to provide a ceramic-based salt battery multi-component integrated sealing method, which can effectively solve the problems in the background technology.

[0011] To achieve the above object, the technical solution adopted by the present invention is:

[0012] A ceramic-based salt battery multi-component integrated sealing method includes the following steps:

[0013] S1: Prepare sealing components: Sealing components include Na-beta-Al 2 O 3 Ceramic tubes, first glass, first alloy, insulating alpha-Al 2 O 3 Ceramic ring, second glass, second alloy and positioning tool;

[0014] S2: Preliminary connection work: connect the first glass, the first alloy, and the insulating alpha-Al 2 O 3 The ceramic ring, the second glass and the second alloy form a sealing assembly, and the Na-beta-Al 2 O 3 The ceramic tube is mounted on top of the first glass;

[0015] S3: Modification treatment: The sealing assembly and Na-beta-Al 2 O 3 The ceramic tube is placed in a reduction furnace, and the temperature in the reduction furnace is slowly raised to 1000° C. in a reducing atmosphere with high-purity hydrogen and argon as sintering atmosphere, wherein the content of the high-purity hydrogen and argon is less than 1%, and the temperature is kept for 3 hours, and then the reduction furnace is cooled to reduce the metal oxides on the surfaces of the first alloy and the second alloy; then, under the condition of slight oxidation of the first alloy and the second alloy, the argon gas flow rate is controlled to be no more than 2%, and the alloy is kept in an argon atmosphere at 750° C. for 3 hours, and then the reduction furnace is cooled to generate oxides on the surfaces of the first alloy and the second alloy, and nitrogen is introduced into the reduction furnace as an inert protective atmosphere, and the nitrogen content is less than 0.5%, so as to prevent the oxidation of the first alloy and the second alloy and the precipitation of metal oxides from the first glass and the second glass;

[0016] S4: Sealing treatment: Adjust the temperature of the reduction furnace to seal the assembly and Na-beta-Al 2 O 3 The ceramic tube is slowly heated to 1200°C at a rate of 3.3°C / min and kept at this temperature for 30 minutes, so that the first glass and the second glass in the sealing assembly are completely melted and spread on the sealing assembly and the Na-beta-Al 2 O 3 The surface of the ceramic tube is then rapidly cooled to 560°C at a rate of 2.7°C / min until the first glass and the second glass undergo glass transition, and then slowly cooled to 360°C at a rate of 0.67°C / min, and finally cooled to room temperature with the reduction furnace to complete the Na-beta-Al 2 O 3 Sealing of ceramic tubes and sealing assemblies;

[0017] S5: Positioning treatment: Preparation with Na-beta-Al 2 O3 The positioning fixture is matched with the size and shape of the ceramic tube, and the positioning fixture is set on the Na-beta-Al 2 O 3 The outer wall of the ceramic tube has at least one positioning fixture on the upper and lower sides.

[0018] Preferably, the Na-beta-Al 2 O 3 The shape of the ceramic tube is not limited, including but not limited to round, square, and flower-shaped, and the positioning tool is made of ceramic material.

[0019] Preferably, the first glass, the first alloy, the insulating alpha-Al 2 O 3 The shapes of the ceramic ring, the second glass and the second alloy are not limited, including but not limited to round, square and flower-shaped. The first glass and the second glass are borosilicate system glasses.

[0020] Preferably, the types of the first alloy and the second alloy include, but are not limited to, Kovar alloy, tin-based alloy, silicon-based alloy, germanium-based alloy, aluminum-based alloy, antimony-based alloy, and magnesium-based alloy.

[0021] Beneficial Effects

[0022] Compared with the prior art, the present invention provides a ceramic-based salt battery multi-component integrated sealing method, which has the following beneficial effects:

[0023] 1. Traditional sealing methods use different methods for different sealing materials. The present invention aims to design an integrated sealing method for multiple components of a ceramic tube for sodium salt batteries, which solves the safety risks caused by the technical complexity and inconsistency of battery equipment due to the step-by-step sealing of the ceramic tube and the insulating ceramic ring, and the insulating ceramic ring and the stainless steel metal.

[0024] 2. The ceramic-based salt battery multi-component integrated sealing method has the characteristics of low cost, simple operation, easy industrialization, and no need for large equipment. The glass sealing material used is a borosilicate glass system with good chemical stability and resistance to alkaline steam and sulfur steam corrosion. It also designs thermal expansion matching of different metals and ceramic components, and thermal matching methods of ceramics and ceramic components. At the same time, this method can be fully automated and controllable without manual labor.

[0025] 3. The ceramic-based salt battery multi-component integrated sealing method is simple in method, simple in process operation, and easy to implement in large-scale production equipment. The sealing materials used for packaging are easily available, low in cost, and high in safety factor. The ceramic sleeve positioning process is convenient and effective, and can achieve excellent sealing effects. At the same time, the sealing components are highly reliable, ensuring battery performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the structure after sealing of the present invention;

[0027] Figure 2 It is an exploded view of the present invention after sealing;

[0028] Figure 3 It is a structural schematic diagram of the positioning tool of the present invention;

[0029] Figure 4 It is an exploded view of the positioning tool of the present invention.

[0030] In the figure: 1. Na-beta-Al 2 O 3 Ceramic tube; 2. First glass; 3. First alloy; 4. Insulating alpha-Al 2 O 3 Ceramic ring; 5. Second glass; 6. Second alloy; 7. Positioning tooling. DETAILED DESCRIPTION

[0031] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0032] like Figure 1-Figure 4 As shown, a ceramic-based salt battery multi-component integrated sealing method includes the following steps:

[0033] S1: Prepare sealing components: Sealing components include Na-beta-Al 2 O 3 Ceramic tube 1, first glass 2, first alloy 3, insulating alpha-Al 2 O 3 Ceramic ring 4, second glass 5, second alloy 6 and positioning tool 7, Na-beta-Al 2 O 3 The shape of the ceramic tube 1 is not limited, including but not limited to round, square, and flower-shaped. The first glass 2, the first alloy 3, the insulating alpha-Al 2 O 3 The shapes of the ceramic ring 4, the second glass 5 and the second alloy 6 are not limited, including but not limited to round, square, and flower-shaped. The first glass and the second glass are borosilicate glass. The types of the first alloy 3 and the second alloy 6 include but are not limited to Kovar alloy, tin-based alloy, silicon-based alloy, germanium-based alloy, aluminum-based alloy, antimony-based alloy, and magnesium-based alloy.

[0034] S2: Preliminary connection work: connect the first glass 2, the first alloy 3, and the insulating alpha-Al 2 O 3The ceramic ring 4, the second glass 5 and the second alloy 6 form a sealing assembly, which seals the Na-beta-Al 2 O 3 The ceramic tube 1 is installed on the top of the first glass 2;

[0035] S3: Modification treatment: The sealing assembly and Na-beta-Al 2 O 3 The ceramic tube 1 is placed in a reduction furnace, and the temperature in the reduction furnace is slowly raised to 1000° C. in a reducing atmosphere with high-purity hydrogen and argon as the sintering atmosphere, wherein the content of the high-purity hydrogen and argon is less than 1%, and the temperature is kept for 3 hours, and then the reduction furnace is cooled to reduce the metal oxides on the surfaces of the first alloy 3 and the second alloy 6; then, under the condition of slight oxidation of the first alloy 3 and the second alloy 6, the argon gas flow rate is controlled not to exceed 2%, and the alloy is kept in an argon atmosphere at 750° C. for 3 hours, and then the reduction furnace is cooled to generate oxides on the surfaces of the first alloy 3 and the second alloy 6, and nitrogen is introduced into the reduction furnace as an inert protective atmosphere, and the nitrogen content is less than 0.5%, which is used to prevent the oxidation of the first alloy 3 and the second alloy 6 and the precipitation of metal oxides from the first glass 2 and the second glass 5;

[0036] S4: Sealing treatment: Adjust the temperature of the reduction furnace to seal the assembly and Na-beta-Al 2 O 3 The temperature of the ceramic tube 1 is slowly raised to 1200°C at a rate of 3.3°C / min and kept at this temperature for 30 minutes, so that the first glass 2 and the second glass 5 in the sealing assembly are completely melted and spread on the sealing assembly and the Na-beta-Al 2 O 3 The surface of the ceramic tube 1 is then rapidly cooled to 560°C at a rate of 2.7°C / min until the first glass 2 and the second glass 5 undergo glass transition, and then slowly cooled to 360°C at a rate of 0.67°C / min, and finally cooled to room temperature with the reduction furnace, thereby completing the Na-beta-Al 2 O 3 Sealing the ceramic tube 1 and the sealing assembly;

[0037] S5: Positioning treatment: Preparation with Na-beta-Al 2 O 3 The size and shape of the ceramic tube 1 are matched with the positioning tool 7, and the positioning tool 7 is set on the Na-beta-Al 2 O 3 The outer wall of the ceramic tube 1 has at least one positioning tool 7 at the top and bottom. Specific embodiment one:

[0039] In step S3, in the reducing atmosphere, when the content of high-purity hydrogen and argon is higher than 1%, the airtightness of the sealing component will be poor;

[0040] Under the condition of slight oxidation of the first alloy 3 and the second alloy 6, when the argon gas flow rate exceeds 2%, the metal sealing component will not be reducible enough, resulting in a decrease in sealing performance;

[0041] When nitrogen is used as an inert protective gas, if its content exceeds 0.5%, insufficient oxidation of metal parts will occur;

[0042] When the temperature change during the sealing operation is not within the range of step S4 of the present invention, the glass sealing performance will be reduced; Specific embodiment 2:

[0044] The modification process of the first alloy 3 and the second alloy 6 also includes the following steps:

[0045] A: Annealing treatment: Place the first alloy 3 and the second alloy 6 raw materials in a vacuum diffusion annealing furnace, first start the mechanical pump to evacuate for 30 minutes, then start the diffusion pump to evacuate until the pressure in the furnace is less than 1×10 -3 Pa, rapidly heated to 1040℃ and kept at this temperature for 24h, and then cooled naturally in the furnace to obtain the first alloy 3 and the second alloy 6 after annealing;

[0046] B: The annealed first alloy 3 and the second alloy 6 are crushed by a crusher and placed in a material container, activated by high-pressure hydrogen absorption in a hydrogen absorption device, dehydrogenated at 150° C., and then sieved with a 200-mesh sieve to obtain powders of the first alloy 3 and the second alloy 6;

[0047] C: Silica coating: prepare vapor-deposited silica and water, and prepare sol with a molar ratio of vapor-deposited silica to water of 1:20, stir evenly, and after forming a uniform sol, add the first alloy 3 and the second alloy 6 powder to be coated while stirring, and stir vigorously until the powder is evenly distributed in the sol to complete the coating. The coated first alloy 3 and the second alloy 6 powder are made into spheres, first let them dry naturally in the air, and then put them into a vacuum carbon tube furnace for sintering, and keep them at 300°C for 2h;

[0048] D: Modification treatment: copper-plated the dried first alloy 3 and the second alloy 6 under acidic conditions, dissolved copper sulfate in water, then added the chelating agent EDTA, heated and stirred at 50°C for 30 minutes to complete the preparation of the solution, first moistened the prepared first alloy 3 and the second alloy 6 with anhydrous ethanol, added formaldehyde dropwise, stirred evenly, added the first alloy 3 and the second alloy 6 together into the solution, stirred vigorously for 10 minutes, filtered out the excess alloy powder, washed three times with deionized water, and dried naturally in the air to complete the modification, and the modified first alloy 3 and the second alloy 6 were made into the required size and shape for sealing.

[0049] Traditional sealing methods use different methods for different sealing materials. The present invention aims to design an integrated sealing method for sodium salt batteries involving multiple components of ceramic tubes, which solves the safety risks caused by the technical complexity and inconsistency of battery equipment due to the step-by-step sealing of ceramic tubes and insulating ceramic rings, and insulating ceramic rings and stainless steel metals. The overall method has the characteristics of low cost, simple operation, easy industrialization, and no need for large equipment. The glass sealing material used is a borosilicate glass system with good chemical stability and resistance to alkaline steam and sulfur steam corrosion. It also designs thermal expansion matching of different metals and ceramic components, and thermal matching methods of ceramics and ceramic components. At the same time, this method can be fully automated and controllable without manual labor. The method is simple, the process operation is simple, and large-scale production equipment is easy to implement. The sealing material used for packaging is easy to obtain, low cost, and high safety factor. The ceramic sleeve positioning process is convenient and effective, and can achieve excellent sealing effects. At the same time, the sealing components are highly reliable and ensure battery performance.

[0050] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for integrating multiple components of a ceramic-based salt battery, characterized in that: The steps include: S1: preparing sealing components: the sealing components include a Na-beta-Al2O3 ceramic tube (1), a first glass (2), a first alloy (3), an insulating alpha-Al2O3 ceramic ring (4), a second glass (5), a second alloy (6) and a positioning tool (7); S2: Preliminary connection work: the first glass (2), the first alloy (3), the insulating alpha-Al2O3 ceramic ring (4), the second glass (5) and the second alloy (6) are assembled into a sealing assembly, and the Na-beta-Al2O3 ceramic tube (1) is installed on the top of the first glass (2); S3: Modification treatment: placing the sealing assembly and the Na-beta-Al2O3 ceramic tube (1) in a reduction furnace, slowly raising the temperature in the reduction furnace to 1000°C in a reducing atmosphere with high-purity hydrogen and argon as the sintering atmosphere, wherein the content of the high-purity hydrogen and argon is less than 1%, maintaining the temperature for 3 hours, and then cooling the reduction furnace to reduce the metal oxides on the surfaces of the first alloy (3) and the second alloy (6); then, under the condition of slight oxidation of the first alloy (3) and the second alloy (6), controlling the argon gas flow rate to not more than 2%, maintaining the temperature in an argon atmosphere at 750°C for 3 hours, and then cooling the reduction furnace to generate oxides on the surfaces of the first alloy (3) and the second alloy (6), and introducing nitrogen as an inert protective atmosphere into the reduction furnace, wherein the nitrogen content is less than 0.5%, to prevent oxidation of the first alloy (3) and the second alloy (6) and precipitation of metal oxides from the first glass (2) and the second glass (5); S4: Sealing treatment: adjusting the temperature of the reduction furnace, slowly heating the sealing assembly and the Na-beta-Al2O3 ceramic tube (1) to 1200°C at a rate of 3.3°C / min and keeping the temperature for 30 minutes, so that the first glass (2) and the second glass (5) in the sealing assembly are completely melted and spread on the surface of the sealing assembly and the Na-beta-Al2O3 ceramic tube (1), then rapidly cooling to 560°C at a rate of 2.7°C / min until the first glass (2) and the second glass (5) undergo glass transition, then slowly cooling to 360°C at a rate of 0.67°C / min, and finally cooling to room temperature along with the reduction furnace, thereby completing the sealing of the Na-beta-Al2O3 ceramic tube (1) and the sealing assembly; S5: Positioning processing: preparing a positioning tool (7) that matches the size and shape of the Na-beta-Al2O3 ceramic tube (1), and sleeve the positioning tool (7) on the upper and lower outer walls of the Na-beta-Al2O3 ceramic tube (1), wherein the number of the positioning tool (7) is at least one.

2. A ceramic-based salt battery multi-component integrated sealing method according to claim 1, characterized in that: The shape of the Na-beta-Al2O3 ceramic tube (1) is not limited, including but not limited to round, square, and flower-shaped, and the positioning tool (7) is made of ceramic material.

3. A ceramic-based salt battery multi-component integrated sealing method according to claim 1, characterized in that: The shapes of the first glass (2), the first alloy (3), the insulating alpha-Al2O3 ceramic ring (4), the second glass (5) and the second alloy (6) are not limited, including but not limited to round, square, and flower-shaped. The first glass and the second glass are borosilicate system glasses.

4. A ceramic-based salt battery multi-component integrated sealing method according to claim 1, characterized in that: The types of the first alloy (3) and the second alloy (6) include, but are not limited to, Kovar alloy, tin-based alloy, silicon-based alloy, germanium-based alloy, aluminum-based alloy, antimony-based alloy, and magnesium-based alloy.

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