Alumina material, preparation method thereof and application of alumina material in thermal runaway protection of lithium ion battery

Abstract

The invention relates to an aluminum oxide material, a preparation method thereof and application of the aluminum oxide material in thermal runaway protection of a lithium ion battery, and relates to the technical field of aluminum oxide materials and battery thermal runaway protection, and physicochemical property parameters of the aluminum oxide material are as follows: the chemical formula is Al2O3, the crystal structure is gamma phase, the particle size range is 2-5 microns, and the microstructure is in a flower-ball hollow shape. The aluminum oxide material provided by the invention can effectively adsorb hydrogen fluoride gas in lithium ion battery thermal runaway leaks when the lithium ion battery is in thermal runaway, and reduces the harm of leaked flue gas after the lithium ion battery is in thermal runaway. Experiments show that the concentration and flow of HF generated after thermal runaway of the battery are simulated, the protection effect on the HF under the conditions of 1000 ppm and 50 mL / min can reach 99% or above, the concentration of HF in gas is remarkably reduced, and harm caused after lithium electric thermal runaway is greatly weakened.

Description

Technical Field

[0001] The present invention relates to the technical field of alumina materials and battery thermal runaway protection, and particularly relates to an alumina material, a preparation method thereof, and an application thereof in the thermal runaway protection of lithium-ion batteries. Background Art

[0002] With the in-depth proposal and wide implementation of the new energy strategy, lithium-ion batteries (hereinafter referred to as "lithium batteries" or "batteries", and related expressions such as "lithium electricity" also refer to the same) have witnessed an unprecedentedly rapid development momentum and have been widely penetrated into various application fields by virtue of their excellent high energy density characteristics and significant green environmental protection advantages. From personal communication devices such as mobile phones and computers to large-scale power and energy storage facilities such as automobiles, ships, and energy storage power stations, the figure of lithium batteries can be found everywhere, becoming an indispensable energy source in modern life.

[0003] However, while the lithium battery industry is booming, a problem that cannot be ignored has emerged: the number of fire accidents caused by electric vehicle batteries is increasing year by year, posing a severe challenge to public safety. Due to the complexity of its internal structure and the high-density energy it carries, once a lithium battery catches fire, its combustion performance is completely different from that of traditional fuel vehicles, showing unique combustion characteristics. Among them, battery thermal runaway, as a common feature of this series of accidents, has sounded the alarm for safety, reminding us that battery safety issues must not be underestimated.

[0004] What is even more worthy of attention is that in certain specific situations, the gas and smoke emissions generated during the thermal runaway of lithium batteries may pose a greater threat than the fire itself. Especially in enclosed environments such as airplanes, submarines, mines, spacecraft, or homes equipped with battery energy storage systems, the accumulation of these harmful gases and smoke may quickly reach dangerous concentrations, posing a serious threat to the safety of personnel's lives and the normal operation of equipment. If this problem cannot be effectively solved, it is very likely to become an obstacle to the large-scale application of this new productive force of lithium batteries, thereby affecting the high-quality development process of the lithium battery industry.

[0005] Research reveals that toxic HF gas can be detected during the thermal runaway of different types of batteries, different states of charge (SOC values), and batteries with different degrees of aging. If a fire or explosion accident caused by the thermal runaway of a lithium battery occurs in a poorly ventilated environment, such as a basement or the interior of a car, the concentration of HF gas will quickly climb to an extremely high level, extremely likely to cause serious safety accidents and pose a great threat to the safety of personnel's lives and property.

[0006] In view of this, in recent years, scholars at home and abroad have conducted in-depth and extensive research on the thermal runaway problem of lithium batteries and proposed various prevention and control solutions. However, unfortunately, for the problem of HF gas leakage during the thermal runaway process, the current research and attention are still insufficient. Therefore, it is urgent to develop new materials and technical means to effectively solve the HF gas problem generated during the thermal runaway of lithium batteries, ensure the safety and reliability of lithium batteries during their wide application, and provide strong guarantee for the sustainable and healthy development of the lithium battery industry. Summary of the Invention

[0007] To solve the above problems, the present invention provides an alumina material, a preparation method thereof, and an application in the thermal runaway protection of lithium-ion batteries.

[0008] In the first aspect, the present invention provides an alumina material, which is a material with a hollow flower ball-like microstructure self-assembled by nanosheets.

[0009] Further, the diameter of the spheres in the microstructure of the alumina material is 2-5 micrometers.

[0010] Further, the X-ray diffraction pattern of the alumina material is as Figure 1 shown, and the scanning electron microscope image of the alumina material is as Figure 2 shown.

[0011] Further, the chemical formula of the alumina material is Al 2 O 3 , and the crystal structure of the alumina material is the γ phase.

[0012] In the second aspect, the present invention provides a preparation method of the alumina material according to any item of the first aspect, and the alumina material is prepared by a hydrothermal method or a combustion method.

[0013] Further, when the alumina material is prepared by the hydrothermal method, the preparation method includes the following steps:

[0014] Dissolve potassium alum and urea in water and stir continuously to obtain a first mixed solution;

[0015] Place the first mixed solution in a reaction kettle for hydrothermal synthesis, naturally cool to room temperature after the reaction, then wash and centrifuge to obtain a white solid;

[0016] Calcine the white solid to obtain the alumina material.

[0017] Further, the heating method for hydrothermal synthesis includes at least one of first microwave heating and external oven heating; the working condition parameters of the first microwave heating include: microwave heating power of 300 - 800 W and reaction time of 20 - 40 min; the working condition parameters of the external oven heating include: oven heating temperature of 150 - 180 °C and reaction time of 6 - 10 hours;

[0018] The steps of washing include washing 2 - 5 times with deionized water and anhydrous ethanol respectively;

[0019] The working condition parameters of the calcination include: heating up to 550 °C - 650 °C at a heating rate of 0.5 °C / min - 5 °C / min and holding for 2 - 4 hours.

[0020] Further, when preparing the alumina material by the combustion method, the preparation method includes the following steps:

[0021] Dissolve the fuel and aluminum nitrate in water and stir continuously to obtain a second mixed solution;

[0022] Perform external muffle furnace heating or second microwave heating on the second mixed solution to obtain the alumina material.

[0023] Further, the molar ratio of the fuel to the aluminum nitrate is 1:(1 - 5), and the fuel includes urea, glycine, sucrose or other hydrocarbons;

[0024] The working condition parameters of the second microwave heating include: microwave heating power of 300 - 800 W and reaction time of 20 - 40 min;

[0025] The working condition parameters of the external muffle furnace heating include: muffle furnace heating temperature of 200 - 600 °C and reaction time of 2 - 6 hours.

[0026] In the third aspect, the present invention provides the application of the alumina material according to any one of the first aspect or the alumina material prepared by the preparation method according to any one of the second aspect in the thermal runaway protection of lithium - ion batteries. The alumina material can effectively adsorb hydrogen fluoride gas in the leakage substances during the thermal runaway of lithium - ion batteries, reducing the harm of the flue gas leaked after the thermal runaway of lithium batteries.

[0027] Further, in the protection test method, by simulating the HF concentration and flow rate generated after the thermal runaway of the battery, the protection effect on HF can reach more than 99% under the conditions of 1000 ppm and 50 mL / min.

[0028] Further, in the protection test method, the material prepared by screening 40 - 80 mesh is filled into a dynamic adsorption tube for testing.

[0029] The above technical solution provided by the embodiment of the present invention has at least the following advantages compared with the prior art:

[0030] The embodiment of the present invention provides an alumina material, a preparation method thereof, and an application in the thermal runaway protection of lithium-ion batteries. The alumina material provided by the present invention can effectively adsorb hydrogen fluoride gas in the leakage of lithium-ion battery thermal runaway during thermal runaway of the lithium-ion battery, reducing the harm of the flue gas leaked after the thermal runaway of the lithium battery. Experiments show that for the HF concentration and flow rate generated after simulating the thermal runaway of the battery, the protection effect on HF can reach more than 99% under the conditions of 1000 ppm and 50 mL / min, significantly reducing the HF concentration in the gas and greatly weakening the harm after the thermal runaway of the lithium battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings herein are incorporated into the specification and constitute a part of this specification, showing embodiments consistent with the present invention and used together with the specification to explain the principles of the present invention.

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0033] Figure 1 It is an X-ray diffraction (XRD) pattern of an alumina material provided by an embodiment of the present invention.

[0034] Figure 2 It is a scanning electron microscope (SEM) image of an alumina material provided by an embodiment of the present invention.

[0035] Figure 3 It is a schematic diagram of a device for verifying the protection effect of the alumina material on HF gas in the present invention.

[0036] Figure 4 It is a breakthrough curve diagram of different methods in the present invention.

[0037] Figure 5 It is a breakthrough curve diagram of different ratios in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0039] Unless otherwise specifically stated, various raw materials, reagents, instruments, and equipment used in the present invention can be obtained through market purchases or prepared by existing methods.

[0040] In a first aspect, the present invention provides an alumina material, and the alumina material is a material with a spherical hollow morphology self-assembled from nanosheets.

[0041] The embodiments of the present invention provide an alumina material. The alumina material provided by the present invention can effectively adsorb hydrogen fluoride gas in the leakage of a lithium-ion battery during thermal runaway, reducing the harm of the flue gas leaked after the thermal runaway of the lithium battery. Experiments show that for the HF concentration and flow rate generated after simulating the thermal runaway of the battery, the protection effect against HF can reach more than 99% under the conditions of 1000 ppm and 50 mL / min, significantly reducing the HF concentration in the gas and greatly weakening the harm after the thermal runaway of the lithium battery.

[0042] In some specific embodiments, the diameter of the spheres in the microscopic morphology of the alumina material is 2 to 5 micrometers.

[0043] In some specific embodiments, the X-ray diffraction pattern of the alumina material is as Figure 1 shown, and the scanning electron microscope image of the alumina material is as Figure 2 shown.

[0044] In some specific embodiments, the chemical formula of the alumina material is Al 2 O 3 , and the crystal structure of the alumina material is the γ phase.

[0045] In a second aspect, the present invention provides a preparation method for the alumina material according to any one of the first aspect, and the alumina material is prepared by a hydrothermal method or a combustion method.

[0046] In some specific embodiments, when the alumina material is prepared by the hydrothermal method, the preparation method includes the following steps:

[0047] Dissolve potassium alum and urea in water and continuously stir to obtain a first mixed solution;

[0048] Place the first mixed solution in a reaction kettle for hydrothermal synthesis. After the reaction is completed, naturally cool it to room temperature, and then wash and centrifuge it to obtain a white solid.

[0049] Calcine the white solid to obtain the alumina material.

[0050] In some specific embodiments, the heating method for the hydrothermal synthesis includes at least one of first microwave heating and external oven heating; the working condition parameters of the first microwave heating include: the microwave heating power is 300 - 800 W, and the reaction time is 20 - 40 min; the working condition parameters of the external oven heating include: the oven heating temperature is 150 - 180 °C, and the reaction time is 6 - 10 hours.

[0051] The steps of the washing include washing 2 - 5 times with deionized water and anhydrous ethanol respectively.

[0052] The working condition parameters of the calcination include: heating up at a heating rate of 0.5 °C / min - 5 °C / min to 550 °C - 650 °C and holding for 2 - 4 hours.

[0053] In some specific embodiments, when preparing the alumina material by the combustion method, the preparation method includes the following steps:

[0054] Dissolve the fuel and aluminum nitrate in water and continuously stir to obtain a second mixed solution.

[0055] Perform external muffle furnace heating or second microwave heating on the second mixed solution to obtain the alumina material.

[0056] In some specific embodiments, the molar ratio of the fuel to the aluminum nitrate is 1:(1 - 5), and the fuel includes urea, glycine, sucrose, or other hydrocarbons.

[0057] The working condition parameters of the second microwave heating include: the microwave heating power is 300 - 800 W, and the reaction time is 20 - 40 min.

[0058] The working condition parameters of the external muffle furnace heating include: the muffle furnace heating temperature is 200 - 600 °C, and the reaction time is 2 - 6 hours.

[0059] In a third aspect, the present invention provides the application of the alumina material according to any one of the first aspect or the alumina material prepared by the preparation method according to any one of the second aspect in the thermal runaway protection of lithium - ion batteries. The alumina material can effectively adsorb hydrogen fluoride gas in the leakage of lithium - ion battery thermal runaway, reducing the harm of the flue gas leaked after the thermal runaway of the lithium battery.

[0060] In some specific embodiments, the protection test method simulates the HF concentration and flow rate generated after the battery thermal runaway, and the protection effect against HF can reach more than 99% under the conditions of 1000ppm and 50mL / min.

[0061] In some specific embodiments, the material prepared in the protection test method is screened with a mesh size of 40-80 and loaded into a dynamic adsorption tube for testing.

[0062] It should be noted that, unless otherwise specified or described, the components and raw materials involved in the aluminum oxide material and its preparation method and application provided in the embodiments of the present invention can be directly commercially available. At the same time, unless otherwise specified or described, the steps involved in the preparation method can be carried out according to the steps and parameters disclosed in the prior art or using existing equipment, and the present invention document will not repeat them one by one.

[0063] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples that do not specify specific conditions are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0064] Example 1

[0065] This example provides an aluminum oxide material, and is used as a protective material for hydrogen fluoride in thermal runaway leakage of lithium-ion batteries, and adsorbs HF in the treatment gas. The protective material is γ-Al 2 O 3 The hydrothermal preparation method of the protective material comprises the following steps: 2 O 3 Characterization spectra of adsorption materials such as Figure 1 and Figure 2 As shown, the particle size ranges from 2 to 5 microns;

[0066] S1. Dissolve potassium aluminum sulfate dodecahydrate and urea in water, mix thoroughly, stir for 5 to 15 minutes, put into a reactor, heat, and filter to obtain a precipitate;

[0067] S2. The precipitate was washed with water 2 to 5 times, washed with anhydrous ethanol 2 to 5 times, dried at 80°C for 5 hours, and calcined at 600°C for 3 hours to obtain a white solid γ-Al 2 O 3 ;

[0068] In S1, the molar concentrations of the aqueous solutions of potassium aluminum sulfate dodecahydrate and urea are 0.05 mol / L and 0.1 mol / L, respectively.

[0069] In S1, the heating method can be to heat in an oven at 170 °C for 7.5 hours, or use microwave with 300 w to heat for 30 min.

[0070] Or the preparation method of the protective material by combustion includes the following steps:

[0071] S1. Dissolve the fuel and aluminum nitrate in water, mix well, stir for 5 - 15 min, and then heat-treat to obtain white solid γ-Al 2 O 3 .

[0072] In S1, the fuel can be urea, glycine, sucrose or other hydrocarbons;

[0073] In S1, the molar ratio of the fuel to aluminum nitrate is 2.5;

[0074] In S1, the heating method can be to heat in a muffle furnace at 400 °C for 4 hours, or use microwave with 800 w to heat for 20 min.

[0075] A protective material and its application for treating hydrogen fluoride in the thermal runaway leakage of lithium-ion batteries. After using this material, the HF concentration in the gas can be significantly reduced, and the elimination rate of HF can still reach more than 99% after continuous treatment for 4 h.

[0076] Example 2: Device for verifying the protective effect on HF gas

[0077] According to the Figure 3 shown device for dynamic adsorption test. The HF gas is adsorbed and treated by the dynamic adsorption tube and then flows into the absorption liquid, where it exists in the form of fluoride ions. The fluoride ion concentration in the solution is monitored in real time using a fluoride ion selective electrode; through further calculation, the HF concentration in the adsorbed gas is determined.

[0078] The specific conditions are as follows: Load 0.1 g of the sample in a dynamic adsorption tube with an inner diameter of 6 mm and conduct a breakthrough experiment in HF gas with a concentration of 1000 ppm. The experiment is carried out at room temperature, and the flow rate is controlled at 50 ml·min-1. Select 10 ppm of the HF outlet concentration as the breakthrough end point.

[0079] The specific calculation method is as follows:

[0080] Set the gas flow rate as ν ml / min, the volume concentration of HF gas after adsorption by the dynamic tube is ω ppm, and the experimental reaction time is t min. Then, within this period of time, the cumulative gas volume introduced into the device is ν·t ml, and the volume of HF gas passing through is ν·t·ω·10 -6 ml, and the corresponding amount of substance under standard conditions:

[0081]

[0082] Assume that all HF gas is absorbed by V L of buffer solution, then the fluoride ion concentration in the solution:

[0083]

[0084] Thus, it can be seen that the partial derivative of c in the solution F- with respect to time is linearly related to the volume concentration ω of HF in the gas, that is, when the gas flow rate ν is determined:

[0085]

[0086] Example 3: Testing the HF adsorption effect of hydrothermal method and combustion method

[0087] Plot the breakthrough curves of the materials obtained by different methods as Figure 4 shown. The properties of the materials prepared by the two hydrothermal methods are similar, and the HF adsorption effects are similar, with similar protection times and adsorption amounts; while the alumina material prepared by the combustion method has better protection performance and can adsorb HF gas for a long time. The adsorption time of the alumina material prepared by the solution combustion method can reach 221 minutes. This is because the material prepared by the combustion method has a large specific surface area and rich microporous structure, providing more reactive sites, which can fully contact and react with the passing HF gas.

[0088] The specific protection times are shown in Table 1.

[0089] Table 1 Protection times of different methods

[0090] Material preparation method Combustion method - microwave Combustion method - heating Hydrothermal method - heating Hydrothermal method - microwave Protection time / min 209 221 170 185

[0091] Example 4: Testing the HF adsorption of different proportions of fuel in the combustion method

[0092] On the basis of Example 1, taking the fuel urea as an example, the alumina materials prepared with different ratios of aluminum nitrate to urea are subjected to adsorption tests. The concentration ratios of the two are set to 1.5, 1.75, 2, 2.25, and 2.5 respectively. The breakthrough curves of different ratios are as Figure 5 shown and the protection times of different ratios are shown in Table 2.

[0093] Table 2 Protection times of different ratios

[0094] Aluminum nitrate: urea 1.5 1.75 2 2.25 2.5 Protection time / min 221 240 282 263 221

[0095] In summary, the embodiments of the present invention provide an alumina material, a preparation method thereof, and an application in the thermal runaway protection of lithium-ion batteries. The alumina material provided by the present invention can effectively adsorb hydrogen fluoride gas in the leakage substances during the thermal runaway of lithium-ion batteries, reducing the harm of the flue gas leaked after the thermal runaway of lithium batteries. Experiments show that under the conditions of HF concentration and flow rate generated after the simulated battery thermal runaway of 1000 ppm and 50 mL / min, the protection effect on HF can reach more than 99%, significantly reducing the HF concentration in the gas and greatly weakening the harm after the thermal runaway of lithium batteries.

[0096] The various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be construed as a rigid limitation on the scope of the present invention; therefore, it should be considered that the description of the range has specifically disclosed all possible sub-ranges and individual values within that range. For example, it should be considered that the description of the range from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and individual numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0097] The above description is only the specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather will conform to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. An aluminum oxide material, characterized in that: The aluminum oxide material is a material formed by self-assembly of nanosheets and having a microscopic morphology of a hollow flower ball.

2. The aluminum oxide material according to claim 1, characterized in that: The diameter of the spheres in the microscopic morphology of the aluminum oxide material is 2 to 5 microns.

3. The aluminum oxide material according to claim 1, characterized in that: The X-ray diffraction pattern of the aluminum oxide material is shown in FIG1 , and the scanning electron microscope pattern of the aluminum oxide material is shown in FIG2 .

4. The aluminum oxide material according to claim 1, characterized in that: The chemical formula of the aluminum oxide material is Al2O3, and the crystal structure of the aluminum oxide material is γ phase.

5. A method for preparing the aluminum oxide material according to any one of claims 1 to 4, characterized in that: The alumina material is prepared by a hydrothermal method or a combustion method.

6. The method for preparing the aluminum oxide material according to claim 5, characterized in that: When the alumina material is prepared by a hydrothermal method, the preparation method comprises the following steps: Dissolving potassium aluminum sulfate and urea in water and continuously stirring to obtain a first mixed solution; The first mixed solution is placed in a reactor for hydrothermal synthesis, and after the reaction is completed, it is naturally cooled to room temperature, and then washed and centrifuged to obtain a white solid; The white solid is calcined to obtain the alumina material.

7. The method for preparing the aluminum oxide material according to claim 6, characterized in that: The heating method of the hydrothermal synthesis includes at least one of first microwave heating and oven external heating; the working condition parameters of the first microwave heating include: microwave heating power of 300-800W, reaction time of 20-40min; the working condition parameters of the oven external heating include: oven heating temperature of 150-180°C, reaction time of 6-10 hours; The washing step comprises washing with deionized water and anhydrous ethanol for 2 to 5 times respectively; The working condition parameters of the calcination include: heating to 550°C to 650°C at a heating rate of 0.5°C / min to 5°C / min and keeping the temperature for 2-4 hours.

8. The method for preparing the aluminum oxide material according to claim 5, characterized in that: When the alumina material is prepared by a combustion method, the preparation method comprises the following steps: Dissolving the fuel and aluminum nitrate in water and stirring continuously to obtain a second mixed solution; The second mixed solution is subjected to external muffle furnace heating or second microwave heating to obtain an aluminum oxide material.

9. The method for preparing the aluminum oxide material according to claim 8, characterized in that: The molar ratio of the fuel to the aluminum nitrate is 1:(1-5), and the fuel includes urea, glycine, sucrose or other hydrocarbons; The working condition parameters of the second microwave heating include: microwave heating power of 300-800W, reaction time of 20-40min; The working condition parameters of the muffle furnace external heating include: the muffle furnace heating temperature is 200-600° C., and the reaction time is 2-6 hours.

10. Use of the aluminum oxide material according to any one of claims 1 to 4 or the aluminum oxide material prepared by the method for preparing the aluminum oxide material according to any one of claims 5 to 8 in thermal runaway protection of lithium-ion batteries, characterized in that: The aluminum oxide material effectively absorbs hydrogen fluoride gas in the thermal runaway leakage of the lithium ion battery when the lithium ion battery is in thermal runaway, thereby reducing the hazard of smoke leakage after the lithium battery is in thermal runaway.

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