Corrosion-resistant sealing glass material for lithium battery and preparation method of corrosion-resistant sealing glass material

Abstract

The invention discloses a corrosion-resistant sealing glass material for a lithium battery and a preparation method of the corrosion-resistant sealing glass material, and the sealing glass material comprises the following components in molar percentage: 20%-29% of SiO2, 12%-25% of Al2O3, 12%-25% of B2O3, 5%-15% of alkali metal oxide and 5%-15% of alkaline earth metal oxide. Wherein the alkali metal oxide comprises 1%-5% of LiO2, 1%-5% of K2O and 1%-5% of Na2O; the alkaline earth metal oxide comprises 1%-10% of BaO, 0%-5% of CaO and 0%-5% of SrO. By accurately controlling the content of each component, the sealing glass material with good sealing performance and excellent corrosion resistance is obtained, the corrosion of electrolyte to the glass material can be remarkably inhibited, and the stability and reliability of lithium battery products are remarkably improved; and the glass material has a thermal expansion coefficient matched with related metal, so that the thermal stress in the sealing process can be reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sealing glass materials, in particular to a corrosion-resistant sealing glass material for lithium battery and a preparation method thereof. BACKGROUND

[0002] With the rapid development of mobile devices, electric vehicles, energy storage systems and other fields, the market demand for lithium ion batteries has grown rapidly, and sealing glass, as one of the key protective materials for lithium ion batteries, has been widely used in the industry. Sealing glass not only needs to have excellent chemical corrosion resistance, but also needs to have good air tightness and insulation to ensure the safety and reliability of the battery.

[0003] The invention patent with application number 202210173208.8 discloses a lithium corrosion-resistant sealing glass, sealing cover group and lithium battery. The sealing glass comprises SiO2, Al2O3, B2O3, alkali metal oxide and alkaline earth metal oxide, and the alkali metal oxide comprises Li2O. The content of SiO2 is 10-19%, and the content of Al2O3 is 22-35%, based on 100% of the mass of the sealing glass. The sealing glass of the invention has low SiO2 content, high Al2O3 content and a small amount of Li2O added, which can inhibit the reaction between lithium metal and glass, maintain excellent mechanical strength, excellent lithium corrosion resistance and appropriate thermal expansion coefficient of the sealing glass, and improve the chemical stability and service life of the sealing glass.

[0004] However, the existing sealing glass material still has deficiencies in terms of electrolyte corrosion resistance, thermal expansion coefficient matching and sealing temperature, which limits its application in certain specific occasions. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application aims to provide a corrosion-resistant sealing glass material for lithium battery and a preparation method thereof, which aims to improve the corrosion resistance, thermal expansion coefficient matching and process adaptability of the sealing glass. By precisely controlling the content of each component, a sealing glass material with good sealing performance and excellent corrosion resistance is obtained, which can significantly inhibit the corrosion of electrolyte on the glass material and significantly improve the stability and reliability of lithium battery products. The glass material has a thermal expansion coefficient compatible with related metals, which helps to reduce thermal stress during sealing.

[0006] The technical scheme adopted by the present application to solve the technical problem is: a corrosion-resistant sealing glass material for lithium battery, the sealing glass material comprises the following components in terms of mole percentage: SiO2 20-29%, Al2O3 12-25%, B2O3 12-25%, alkali metal oxide 5-15%, alkaline earth metal oxide 5-15%; wherein the alkali metal oxide comprises: LiO2 1-5%, K2O 1-5%, Na2O 1-5%; the alkaline earth metal oxide comprises: BaO 1-10%, CaO 0-5%, SrO 0-5%.

[0007] A preparation method of a corrosion-resistant sealing glass material for lithium battery, comprising the following steps:

[0008] 1) Raw material weighing and crucible treatment: accurately weigh each component raw material according to the above formula; clean and dry the melting container-crucible to remove the impurities and moisture on the inner wall;

[0009] 2) Mixing: transfer the accurately weighed raw materials to the mixer for thorough mixing;

[0010] 3) Melting: melt the mixed material in a high-temperature furnace, the melting temperature is 1400-1600 DEG C, the high-temperature holding time is 55-80 min, and the molten glass liquid is obtained after high-temperature melting;

[0011] 4) Rod building and water quenching: pour part of the glass liquid into a graphite mold for annealing, the annealing temperature is 500-600 DEG C, and the holding time is more than 12 h, so as to fully eliminate the residual stress in the glass, facilitate subsequent processing and thermal performance characterization; pour the remaining glass liquid into a quenching solution-ice water mixture quickly, so that it quickly crosses the crystallization temperature and becomes a glass state, and then is dried at 100-150 DEG C for more than 5 h to obtain glass fragments;

[0012] 5) Ball milling: place the glass fragments in a ball mill and add agate grinding balls, ball mill for 60-90 min, and then sieve out glass powder below 200 mesh for use;

[0013] 6) Forming: place the -200 mesh glass powder in a mixed liquid for slurry preparation, and then granulate and press to obtain a sealing glass green body;

[0014] 7) Degumming: place the sealing glass green body in a muffle furnace for degumming, and the high-density sealing glass body is obtained after degumming.

[0015] Further, in step 2), the material is placed in a V-shaped mixer, and the mixing time is 45-60 min.

[0016] Further, in step 3), the glass material undergoes a temperature rising, high-temperature melting and temperature falling stage, and a staged temperature rising and holding process is adopted, so that the raw materials fully react to form a uniform phase.

[0017] Further, in step 3), the temperature rising rate in the initial temperature rising stage is 3℃ / min, and the time is 8-9h; the core principle of the high-temperature melting stage is to keep the raw materials at the melting boiling point for a long time to avoid thermal shock of the raw materials to cause the crucible to burst, the high-temperature melting temperature is 1400-1600℃, and the melting time is 12h; the temperature falling rate should be fast, and the discharge temperature is lower than the melting temperature by 100-200℃.

[0018] Further, in step 5), the ball mill is a planetary ball mill, and the mass of the glass fragments is 1.5-1.8 times the mass of the grinding balls.

[0019] Further, in step 6), the mixed liquid phase is composed of deionized water, a dispersing agent and a binder, the pulping time is 80-100min, and the rotation speed of the prilling tower is 2-5r / s.

[0020] Further, in step 7), the degumming temperature is 500-600℃, and the degumming time is 45-60min.

[0021] Further, the shell, the glass blank and the core column are subjected to high-temperature sealing in a high-temperature chain furnace, so that diffusion reaction occurs at the shell-glass and glass-core column interfaces to form a good sealing interface; in the sealing process, the sintering furnace is a chain furnace protected by a nitrogen atmosphere, the temperature of each temperature zone is 600-650℃, 750-835℃, 900-950℃, 900-950℃, 900-950℃, 780-880℃, 630-700℃ and 500-600℃, and the mesh belt feeding rate is 30-70mm / min.

[0022] Further, the shell material is 316L stainless steel, 304 stainless steel or 4J29 Kovar alloy, and the core column material is 4J28, 4J29 or 4J50.

[0023] The beneficial effects of the present application are: compared with the prior art, the corrosion-resistant sealing glass material for lithium battery and the preparation method thereof provided by the present application accurately control the content of each component, and by adjusting the molar ratio of SiO2, Al2O3 and alkali metal oxides (LiO2, K2O and Na2O), the prepared sealing glass material can significantly inhibit the reaction of thionyl chloride electrolyte and glass, and improve the corrosion resistance of lithium battery products. The glass material has a thermal expansion coefficient matching the shell and the core column, which helps to reduce the thermal stress in the sealing process; in addition, the sealing glass material of the present application has excellent airtightness and insulation, which can effectively protect the internal structure of the battery and improve the stability and reliability of the sealing structure. Attached Figure Description

[0024] Figure 1 This is a flowchart illustrating the preparation process of the glass material of this invention.

[0025] Figure 2 This is a front view of the lithium battery sealing product prepared according to the present invention.

[0026] 1 is the shell, 2 is the glass, and 3 is the core. Detailed Implementation

[0027] The present invention will be further illustrated below with specific embodiments. However, these examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0028] Example 1

[0029] A method for preparing a corrosion-resistant sealing glass material for lithium-ion batteries includes the following steps:

[0030] 1) Raw material weighing and crucible treatment: The sealing glass material comprises the following components by molar percentage: SiO2 25%, Al2O3 25%, B2O3 20%, LiO 25%, K2O 5%, Na2O 5%, BaO 10%, and CaO 5%. Each component raw material is accurately weighed according to the above formula; the melting container / crucible is cleaned and dried to remove impurities and moisture from the inner wall.

[0031] 2) Mixing: Transfer the accurately weighed raw materials to a V-type mixer for thorough mixing. The mixing time is 45-60 minutes.

[0032] 3) Melting: The mixture is melted in a high-temperature furnace at a temperature of 1400–1600℃ for 60–80 minutes to obtain molten glass. The glass material undergoes heating, high-temperature melting, and cooling stages, employing a phased heating and holding process to ensure sufficient reaction between the raw materials and the formation of a homogeneous phase. The initial heating rate is 3℃ / min for 8–9 hours. The core principle of the high-temperature melting stage is to keep the raw materials near their melting and boiling points for a longer period to prevent thermal shock that could cause the crucible to crack. The high-temperature melting temperature is 1400–1600℃ for 12 hours. The cooling rate should be relatively fast, with the furnace exit temperature 100–200℃ lower than the melting temperature.

[0033] 4) Molten glass forming and water quenching: Part of the molten glass is poured into a graphite mold for annealing at a temperature of 500-600℃ for more than 12 hours to fully eliminate residual stress inside the glass for subsequent processing and thermal property characterization; the remaining molten glass is quickly poured into a quenching solution-ice water mixture to rapidly pass through the crystallization temperature and become glassy, ​​and then dried at 100-150℃ for more than 5 hours to obtain glass fragments;

[0034] 5) Ball milling: Place the glass fragments in a planetary ball mill and add agate grinding balls (material:ball = 1.6:1). The mass of the glass fragments is 1.5 to 1.8 times the mass of the grinding balls. The ball milling time is 60 to 90 minutes. Then sieve out glass powder with a mesh size of less than 200 for later use.

[0035] 6) Molding: -200 mesh glass powder is placed in the mixed liquid phase for pulping, and then granulated and pressed to obtain sealed glass green body; the mixed liquid phase consists of deionized water, dispersant and binder, the pulping time is 80 to 100 min, and the granulation tower speed is 2 to 5 r / s.

[0036] 7) Degumming: Place the sealed glass preform in a muffle furnace for degumming at a temperature of 500-600℃ for 45-60 minutes. After degumming, a high-density sealed glass preform can be obtained.

[0037] Sealing: The shell, glass preform, and core are sealed at high temperature in a high-temperature chain furnace, causing a diffusion reaction at the shell-glass and glass-core interface to form a good sealing interface. During the sealing process, the sintering furnace is a chain furnace protected by a nitrogen atmosphere, with eight temperature zones of 620℃, 800℃, 940℃, 940℃, 940℃, 800℃, 650℃, and 520℃, and the mesh belt feeding rate is 45mm / min.

[0038] In this embodiment, the shell material is 316L stainless steel, and the core column material is 4J28.

[0039] Example 2

[0040] A method for preparing a corrosion-resistant sealing glass material for lithium-ion batteries includes the following steps:

[0041] 1) Raw material weighing and crucible treatment: The sealing glass material comprises the following components by molar percentage: SiO2 29%, Al2O3 21%, B2O3 24%, LiO2 3%, K2O 5%, Na2O 5%, BaO 4%, CaO 4%, and SrO 5%. Each component raw material is accurately weighed according to the above formula; the melting container / crucible is cleaned and dried to remove impurities and moisture from the inner wall.

[0042] 2) Mixing: the precisely weighed raw materials are transferred to a V-type mixer for thorough mixing, and the mixing time is 45-60 min;

[0043] 3) Melting: the mixed materials are melted in a high-temperature furnace, the melting temperature is 1400-1600℃, the high-temperature holding time is 60-80 min, and the molten glass is obtained after high-temperature melting; the raw materials are fully reacted to form a uniform phase by adopting the staged heating and holding process during the heating, high-temperature melting and cooling stages; the initial heating rate is 3℃ / min, and the time is 8-9 h; the core principle of the high-temperature melting stage is to hold the raw materials near the melting point for a long time to avoid thermal shock of the raw materials and cracking of the crucible, the high-temperature melting temperature is 1400-1600℃, and the melting time is 12 h; the cooling rate should be fast, and the furnace outlet temperature is 100-200℃ lower than the melting temperature.

[0044] 4) Rod building and water quenching: the glass liquid is poured into a graphite mold for annealing, the annealing temperature is 500-600℃, and the holding time is more than 12 h to fully eliminate the residual stress in the glass for subsequent processing and thermal performance characterization; the remaining glass liquid is quickly poured into a quenching solution-ice water mixture to quickly cross the crystallization temperature and become a glass state, and then dried at 100-150℃ for more than 5 h to obtain glass fragments;

[0045] 5) Ball milling: the glass fragments are placed in a planetary ball mill and marbled grinding balls (material: ball = 1.6:1) are added, the mass of the glass fragments is 1.5-1.8 times the mass of the grinding balls, the ball milling time is 60-90 min, and then the glass powder below 200 mesh is screened out for use;

[0046] 6) Forming: the -200 mesh glass powder is placed in a mixing liquid phase for pulping, and then granulated and pressed to obtain a sealing glass green body; the mixing liquid phase is composed of deionized water, a dispersing agent and a binder, the pulping time is 80-100 min, and the granulating tower rotation speed is 2-5 r / s.

[0047] 7) Degreasing: the sealing glass green body is placed in a muffle furnace for degreasing, the degreasing temperature is 500-600℃, and the degreasing time is 45-60 min; after degreasing, a high-density sealing glass biscuit is obtained.

[0048] Sealing: the shell, the glass blank, and the core column are sealed by a high-temperature chain furnace, so that a diffusion reaction occurs at the shell-glass and glass-core column interfaces to form a good sealing interface; the sealing process is carried out in a nitrogen atmosphere chain furnace with eight temperature zones at 640℃, 820℃, 920℃, 920℃, 920℃, 800℃, 670℃, and 550℃, respectively, and the web belt feeding rate is 30 mm / min.

[0049] In this embodiment, the shell material is 304 stainless steel, and the core column material is 4J29.

[0050] The performance test results of the glass-lithium battery terminals obtained in Examples 1 and 2 above are shown in Table 1 below:

[0051]

[0052] Comparative Example 1

[0053] Comparative Example 1 uses the same preparation method as Example 1, except that the sealing glass material has different components, which include the following components in terms of mole percentage: SiO2 15%, Al2O3 30%, B2O3 20%, LiO2 5%, K2O 5%, Na2O 5%, BaO 10%, CaO 5%, and SrO 5%.

[0054] Comparative Example 2

[0055] Comparative Example 1 uses the same preparation method as Example 1, except that the sealing glass material has different components, which include the following components in terms of mole percentage: SiO2 30%, Al2O3 10%, B2O3 24%, LiO2 3%, K2O 7%, Na2O 5%, BaO 10%, CaO 4%, and SrO 7%.

[0056] The performance test results of the glass-lithium battery terminals obtained in Comparative Examples 1 and 2 above are shown in Table 2 below:

[0057]

[0058] The lithium battery terminal sintered by the glass material of Comparative Examples 1 and 2 has excellent insulation and air tightness, but poor corrosion resistance, mainly because the Si and Al contents of the glass material are quite different. SiO2 is the main forming body of the glass network, based on the [SiO4] tetrahedral structure, connected by bridge oxygen (Si-O-Si) to form a three-dimensional network. When the SiO2 content is high, the glass network is more dense, and the chemical stability and mechanical strength are higher. Al2O3 exists in the form of [AlO4] tetrahedron or [AlO6] octahedron in the glass. When the Si and Al contents are quite different, Al2O3 may exist more in the form of [AlO6], which destroys the continuity of the glass network, resulting in a loose network structure. The large difference in Si and Al contents will lead to the non-uniformity of the glass network structure, which may reduce the chemical stability and mechanical strength of the glass. The sealing glass product prepared by using the ratio of the application has good corrosion resistance, and the glass and metal have good thermal adaptability, meeting the needs of industrial production.

[0059] The above embodiments are only used to illustrate the application, but not to limit the application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the application. Therefore, all equivalent technical solutions belong to the scope of the application, and the patent protection scope of the application should be defined by the claims.

Claims

1. A corrosion resistant sealing glass material for lithium battery, characterized by: The sealing glass material comprises the following components in terms of mole percentage: SiO2 20% to 29%, Al2O3 12% to 25%, B2O3 12% to 25%, alkali metal oxide 5% to 15%, alkaline earth metal oxide 5% to 15%; wherein the alkali metal oxide comprises: LiO2 1% to 5%, K2O 1% to 5%, Na2O 1% to 5%; the alkaline earth metal oxide comprises: BaO 1% to 10%, CaO 0% to 5%, SrO 0% to 5%.

2. The method for preparing a corrosion-resistant sealing glass material for lithium-ion batteries as described in claim 1, characterized in that, The method comprises the following steps: 1) raw material weighing and crucible processing: accurately weighing each component raw material according to the above formula; cleaning and drying the melting container-crucible to remove the impurities and moisture on the inner wall; 2) mixing: transferring the accurately weighed raw material to the mixer for sufficient mixing; 3) melting: melting the mixed material in a high-temperature furnace, the melting temperature is 1400 to 1600 ℃, the high-temperature holding time is 55 to 80 min, and the molten glass liquid is obtained after high-temperature melting; 4) rod building and water quenching: pouring part of the glass liquid into a graphite mold for annealing, the annealing temperature is 500 to 600 ℃, and the holding time is more than 12 h; the remaining glass liquid is quickly poured into a quenching solution-ice water mixture to quickly cross the crystallization temperature and become a glass state, and then is dried at 100 to 150 ℃ for more than 5 h to obtain glass fragments; 5) ball milling: placing the glass fragments in a ball mill and adding agate grinding balls, the ball milling time is 60 to 90 min, and then the glass powder below 200 mesh is screened out for use; 6) forming: placing the glass powder of-200 mesh in a mixing liquid phase for slurry preparation, and then granulating and pressing to obtain a sealing glass green body; 7) degumming: placing the sealing glass green body in a muffle furnace for degumming, and the high-density sealing glass biscuit is obtained after the degumming is completed.

3. The method for preparing a corrosion-resistant sealing glass material for lithium-ion batteries as described in claim 2, characterized in that: In step 2), the material is placed in a V-shaped mixer, and the mixing time is 45 to 60 min.

4. The method for preparing a corrosion-resistant sealing glass material for lithium-ion batteries as described in claim 2, characterized in that: In step 3), the glass material undergoes the stages of temperature rising, high-temperature melting and temperature falling, and the stage temperature rising and holding process is adopted.

5. The method for preparing a corrosion-resistant sealing glass material for lithium-ion batteries as described in claim 4, characterized in that: In step 3), the initial temperature rising stage has a temperature rising rate of 3 ℃ / min and a time of 8 to 9 h; the high-temperature melting stage has a melting temperature of 1400 to 1600 ℃ and a melting time of 12 h; and the furnace outlet temperature is 100 to 200 ℃ lower than the melting temperature.

6. The method for preparing a corrosion-resistant sealing glass material for lithium-ion batteries as described in claim 2, characterized in that: In step 5), the ball mill is a planetary ball mill, and the mass of the glass fragments is 1.5 to 1.8 times the mass of the grinding balls.

7. The method for preparing a corrosion-resistant sealing glass material for lithium-ion batteries as described in claim 2, characterized in that: In step 6), the mixing liquid phase is composed of deionized water, dispersant and binder, the slurry preparation time is 80 to 100 min, and the granulating tower rotates at a speed of 2 to 5 r / s.

8. The method for preparing a corrosion-resistant sealing glass material for lithium-ion batteries as described in claim 2, characterized in that: In step 7), the degumming temperature is 500 to 600 ℃, and the degumming time is 45 to 60 min.

9. The method for preparing a corrosion-resistant sealing glass material for lithium-ion batteries as described in claim 2, characterized in that: The shell, the glass blank and the core column are sealed by a high-temperature chain furnace, so that diffusion reaction occurs at the shell-glass and glass-core column interfaces to form a good sealing interface; the sealing process is carried out in a nitrogen atmosphere chain furnace, the temperature of each temperature zone is 600-650℃, 750-835℃, 900-950℃, 900-950℃, 900-950℃, 780-880℃, 630-700℃ and 500-600℃, and the mesh belt feeding rate is 30-70mm / min.

10. The method for preparing a corrosion-resistant sealing glass material for lithium-ion batteries as described in claim 9, characterized in that: The shell is made of 316L stainless steel, 304 stainless steel or 4J29 Kovar alloy, and the core column is made of 4J28, 4J29 or 4J50.

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