A Tubular Battery Non-Uniform Electrolyte and Its Preparation Method

Abstract

The present invention relates to the technical field of storage batteries, and specifically proposes a tubular battery non-uniform electrolyte, including a first colloidal electrolyte, a second colloidal electrolyte and a third colloidal electrolyte, wherein the three electrolytes are respectively distributed in the interior of the pole group of the tubular battery, between the periphery of the pole group and the bus bar, and the area above the bus bar, and the first colloidal electrolyte, the second colloidal electrolyte and the third colloidal electrolyte all include a mother liquor, and the mother liquor is calculated by weight, including 10 parts of water, 1.5-2.5 parts of mesoporous SiO2 nanoparticles, 0.8-1.2 parts of polystyrene-b-poly(2-vinylpyridine) micelles, 0.01-0.05 parts of photoinitiators, 0.01-0.05 parts of antioxidants and 0.3 parts of dispersants, and the first colloidal electrolyte and the second colloidal electrolyte also include sulfuric acid solution. The synergistic effect of the gradient electrolyte design and the mesoporous SiO2 / micelle composite system is adopted to significantly improve the comprehensive performance of the tubular colloidal battery.

Description

Technical Field

[0001] The present invention relates to the technical field of storage batteries, and particularly to a non-uniform electrolyte for tubular batteries and a preparation method thereof. Background Art

[0002] As an important innovation direction of lead-acid batteries, colloidal lead-acid batteries are widely used in fields such as electric vehicles and energy storage systems due to characteristics such as electrolyte solidification, no acid mist leakage, and excellent low-temperature performance. However, traditional colloidal electrolytes generally have technical bottlenecks such as poor gel network stability, easy hydration stratification, and out-of-control microcracks. For example, in an electrolyte system using fumed silica or silica sol as a gelling agent, although sulfuric acid can be fixed through a three-dimensional silicon-oxygen network, the gel has poor thixotropy and insufficient mechanical strength, and is prone to colloidal shrinkage and microcrack expansion due to the expansion stress of the electrode plate during charge and discharge cycles, thereby causing problems such as electrolyte stratification and active material shedding. In addition, although the existing technology can partially improve the gel strength by adding modified glass fibers or increasing the concentration of silica, new contradictions such as a decrease in ionic conductivity and an increase in cost are brought about.

[0003] Current patented technologies for improving colloidal electrolytes mostly focus on single-performance optimization and lack a systematic design for mechanical-electrochemical co-regulation. For example, enhancing the gel network by chemically grafting quaternary ammonium salts onto glass fibers increases the gel strength to an insertion depth of 1.42 mm, but the interface compatibility between its rigid inorganic fibers and the organic colloidal matrix is poor, resulting in blocked ion migration channels; preparing a highly dispersed colloidal mother liquor using a nano-high-speed cutting process achieves particle size control and Zeta potential optimization, but still relies on the traditional staged gelling process and cannot suppress the gradient stress mismatch during the colloidal solidification process.

[0004] In view of the above problems, there is an urgent need to develop an innovative solution for colloidal electrolytes that takes into account mechanical stability, electrochemical performance, and process compatibility. Summary of the Invention

[0005] In view of this, the present invention proposes a non-uniform electrolyte for tubular batteries and a preparation method thereof, aiming to improve the cycle performance of colloidal storage batteries.

[0006] The technical solution of the present invention is implemented as follows: The present invention provides a tubular battery non-uniform electrolyte, which includes a first colloidal electrolyte, a second colloidal electrolyte and a third colloidal electrolyte. The three electrolytes are respectively distributed in the interior of the pole group of the tubular battery, between the periphery of the pole group and the bus bar, and the area above the bus bar. The first colloidal electrolyte, the second colloidal electrolyte and the third colloidal electrolyte all include a mother liquor, which is calculated by weight and includes 10 parts of water, 1.5-2.5 parts of mesoporous SiO2 nanoparticles, 0.8-1.2 parts of polystyrene-b-poly(2-vinylpyridine) micelles, 0.01-0.05 parts of photoinitiator, 0.01-0.05 parts of antioxidant and 0.3 parts of dispersant. The first colloidal electrolyte and the second colloidal electrolyte also include a sulfuric acid solution.

[0007] In this application, mesoporous SiO2 nanoparticles and polystyrene-b-poly(2-vinylpyridine) micelles are introduced to overcome the problem of stress concentration during infusion of traditional gas-phase SiO2 due to the lack of docking and strong hydrogen bonding. The hydrophobic PS core of the polystyrene-b-poly(2-vinylpyridine) micelle is adsorbed on the surface of the mesoporous SiO2, and the pyridine group of the P2VP shell hydrogen bonds with the SiO2 hydroxyl group to form a steric hindrance layer, so that the SiO2 dispersed particle size D90 is less than 200 nm. The hydrophilic segment of the micelle shell P2VP and the mesopores of the mesoporous SiO2 cooperate to construct a graded wetting channel, which greatly improves the penetration rate of the sulfuric acid solution.

[0008] Traditional gas-phase SiO2 relies on physical adsorption to fix sulfuric acid, so the gel shrinkage rate is high, resulting in microcracks in the later stage. The polystyrene-b-poly (2-vinylpyridine) micelles of the present application can cause the pyridine groups therein to transition under the excitation of ultraviolet light, triggering the activation of the CH bonds of adjacent micelles to form a covalent cross-linked network. The silanol groups on the inner wall of the SiO2 mesopores form a hydrogen bond network with the micelle P2VP chain segments, making the gel storage modulus higher than that of pure SiO2 gel. Therefore, the cross-linked network synergistically dissipates mechanical energy through the entropic elastic deformation of the micelles and the plastic deformation of the mesoporous structure under the plate expansion stress.

[0009] The high-mesoporous SiO2 acid storage inside the pole group is combined with high micelle toughening to match the pole plate expansion stress. The medium-concentration mesoporous SiO2 outside the pole group is combined with high acid concentration to enhance ion conduction and mechanical support. The bus area uses low acid concentration and low SiO2 to inhibit acid mist escape and corrosion.

[0010] In some embodiments, the first colloidal electrolyte is composed of a mother liquor and a sulfuric acid solution in a volume ratio of 1:1.2, wherein the concentration of the sulfuric acid solution is 38%, and the mother liquor, calculated by weight, includes 10 parts of water, 2-2.5 parts of mesoporous SiO2 nanoparticles, 1-1.2 parts of polystyrene-b-poly(2-vinylpyridine) micelles, 0.01-0.05 parts of photoinitiator, 0.01-0.05 parts of antioxidant and 0.3 parts of dispersant.

[0011] A higher concentration of mesoporous SiO2 nanoparticles helps to form a rigid skeleton network with a higher storage modulus, which effectively inhibits the propagation of microcracks caused by basic expansion stress.

[0012] In some embodiments, the second colloidal electrolyte is composed of a mother liquor and a sulfuric acid solution in a volume ratio of 1:1.5, wherein the concentration of the sulfuric acid solution is 45%, and the mother liquor, calculated by weight, includes 10 parts of water, 1.5-2 parts of mesoporous SiO2 nanoparticles, 0.8-1 parts of polystyrene-b-poly(2-vinylpyridine) micelles, 0.01-0.05 parts of photoinitiator, 0.01-0.05 parts of antioxidant and 0.3 parts of dispersant.

[0013] By reducing the amount of mesoporous SiO2 nanoparticles in the second colloidal electrolyte, the micelles form a dynamic network through hydrophobic association, triggering the shear thickening effect under high stress, inhibiting the expansion of micro-attendants, and high concentration of sulfuric acid increases the oxygen evolution overpotential and inhibits water decomposition; at the same time, the adsorption effect of mesoporous SiO2 reduces the precipitation of free acid and reduces the interfacial impedance.

[0014] In some embodiments, the third colloidal electrolyte is composed of a mother liquor, which is calculated by weight and includes 10 parts of water, 1 part of mesoporous SiO2 nanoparticles, 0.8 parts of polystyrene-b-poly(2-vinylpyridine) micelles, 0.01-0.05 parts of photoinitiator, 0.01-0.05 parts of antioxidant and 0.3 parts of dispersant.

[0015] A dense protective layer is constructed by the hydrophobic core (PS) of the PS-b-P2VP micelle, which has a lower water vapor permeability and solves the problem of late drying and cracking of traditional colloids.

[0016] In some embodiments, the method for preparing mesoporous SiO2 nanoparticles comprises:

[0017] Step 1: Mix the template agent hexadecyltrimethylammonium p-toluenesulfonate with deionized water and triethanolamine, adjust the pH to 9-10, heat to 75-85°C and stir until clear;

[0018] Step 2: Tetraethyl orthosilicate is added dropwise at a rate of 0.5 ml / min, and the molar ratio of cetyltrimethyl-p-toluenesulfonate to tetraethyl orthosilicate is 1:5. Stir at 300 rpm for 1.5 - 2.5 h while maintaining the temperature to obtain a white precipitate;

[0019] Step 3: Filter and wash, then heat at a rate of 2 °C / min to 500 - 600 °C and calcine for 1 - 2 h to obtain mesoporous SiO₂ nanoparticles;

[0020] The obtained mesoporous SiO₂ nanoparticles have a particle size of 50 - 200 nm and a pore diameter of 3.2 - 7.6 nm.

[0021] In some embodiments, in Step 3, after filtering and washing and before calcining at 500 - 600 °C for 1 - 2 h, the precipitate is dispersed in an ethanol aqueous solution, resorcinol and formaldehyde are added, and stirred for 8 - 12 h, then filtered and washed again, where the mass ratio of resorcinol to the precipitate is (0.5 - 0.8):1, and the molar ratio of resorcinol to formaldehyde is 1:2.

[0022] A uniform coating layer is formed on the surface of the SiO₂ particles using resorcinol and formaldehyde. When calcining at 500 - 600 °C subsequently, the coating layer is carbonized to form an amorphous carbon layer. This carbon layer and the SiO₂ skeleton form a core - shell heterostructure, which improves the ion transport efficiency. This composite structure enhances the compressive strength and helps reduce the cyclic shrinkage rate.

[0023] In some embodiments, the preparation method of the polystyrene - b - poly(2 - vinylpyridine) micelles includes:

[0024] Dissolve 1 g of polystyrene - b - poly(2 - vinylpyridine) powder in 50 ml of a solvent with THF:methanol = 95:5 (v:v). After ultrasonic treatment at 150 W for 20 min, perform evaporation treatment at 20 - 30 °C and a humidity ≤ 30% environment for 12 h to form a micelle film. After vacuum drying, polystyrene - b - poly(2 - vinylpyridine) micelles are obtained, where the molecular weight of the polystyrene - b - poly(2 - vinylpyridine) powder is 25000 - 30000 g / mol.

[0025] In some embodiments, the dispersant is PEG - 4000, the photoinitiator is Irgacure 2959, and the antioxidant is benzotriazole.

[0026] In a second aspect, the present invention also provides a preparation method of the non - uniform electrolyte for the above - mentioned tubular battery, including the following steps:

[0027] Step 1: Mix the mother liquor of the first colloidal electrolyte raw material and the sulfuric acid solution, ultrasonically disperse them, then pour them into the battery and do not exceed the top of the electrode group, place them in a water bath at 15 - 20 °C, and perform a primary charge formation under ultraviolet light irradiation. When the state of charge (SOC) reaches 95%, extract the free acid under vacuum negative pressure to obtain the first colloidal electrolyte;

[0028] Step 2: Mix the mother liquor of the second colloidal electrolyte raw material and the sulfuric acid solution, ultrasonically disperse them, then pour them into the battery and cover the top of the electrode group, not exceeding the bus bar, place them in a water bath at 15 - 20 °C, and perform a primary charge formation. During the charge and discharge process, perform pulsed ultraviolet irradiation. When the SOC reaches 95%, extract the free acid under vacuum negative pressure to obtain the second colloidal electrolyte;

[0029] Step 3: Ultrasonically disperse the mother liquor of the third colloidal electrolyte raw material, then pour it into the battery and cover the bus bar, place it in a water bath at 45 - 60 °C, and perform a primary charge formation to obtain the third colloidal electrolyte.

[0030] In some embodiments, in Step 2, after pouring into the battery and covering the top of the electrode group, before performing the water bath heat preservation, it further includes centrifuging at 8000×g for 10 min at 15 - 20 °C, and then centrifuging at 12000×g for 20 min. The centrifugal force during the above centrifugation process is perpendicular to the axis of the tubular battery.

[0031] In the above embodiments, the colloidal particles are rapidly sedimented by high centrifugal force to remove large - sized pores and undispersed aggregates at the top of the electrode group, forming a preliminary dense layer; subsequent higher centrifugal force drives the colloid to penetrate into the micropores of the electrode plate and the fiber gaps of the separator, forming a multi - level pore structure with more nano - sized pores.

[0032] The present invention has the following beneficial effects compared with the prior art:

[0033] This application adopts the synergistic effect of gradient electrolyte design and mesoporous SiO2 / micelle composite system, significantly improving the comprehensive performance of the tubular colloidal battery. The hierarchical structure precisely matches the functional requirements of high acid storage and anti - swelling inside the electrode group, high ion conduction in the periphery, and acid mist prevention and sealing in the bus bar area. Combining the ordered pores of mesoporous SiO2 and the dynamic cross - linked network of PS - b - P2VP micelles, the efficient adsorption and directional transport of the electrolyte are realized. The ultraviolet curing process and vertical centrifugation control further ensure the uniformity of the gel network and the interfacial bonding strength, improving the battery cycle life, increasing the high - temperature capacity retention rate, and effectively inhibiting the micro - cracks caused by electrode plate swelling and electrolyte stratification. Specific Embodiments

[0034] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0035] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this application, "a plurality" means two or more, unless otherwise specifically defined.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the embodiments of the present invention belong. If the definitions stated in this part are contrary to or inconsistent with the definitions stated in the patents, patent applications, published patent applications, and other publications incorporated herein by reference, the definitions listed in this part shall prevail over the definitions incorporated herein by reference.

[0037] Unless otherwise specified, the methods used in the following examples are all conventional methods. The materials, reagents, and instruments used, unless otherwise specified, are all conventional materials, reagents, and instruments in this field, and those skilled in the art can obtain them through commercial channels.

[0038] When an equivalent, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper limit preferred values and lower limit preferred values, it should be understood that all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value are specifically disclosed, regardless of whether the ranges are separately disclosed. For example, when the range "1 to 5" is disclosed, the described range should be interpreted as including the ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described in this application, unless otherwise stated, the range is intended to include its end values and all integers and fractions within the range. In the specification and claims of this application, range limitations can be combined and / or interchanged, and if not otherwise stated, these ranges include all sub-ranges contained therein.

[0039] Example 1

[0040] This example provides a technical solution for a non-uniform electrolyte of a tubular battery, using carbon-coated mesoporous SiO2 nanoparticles and polystyrene-b-poly(2-vinylpyridine) micelles.

[0041] Its structure includes three layers of electrolyte, and the raw materials of the three layers of electrolyte are as follows:

[0042] The first layer: the mother liquor and sulfuric acid solution are composed of a volume ratio of 1:1.2, wherein the mass concentration of the sulfuric acid solution is 38%, and the mother liquor is calculated by weight and consists of 10 kg of water, 2.5 kg of mesoporous SiO2 nanoparticles, 1.2 kg of polystyrene-b-poly(2-vinylpyridine) micelles, 0.05 kg of photoinitiator Irgacure 2959, 0.05 kg of antioxidant benzotriazole and 0.3 kg of dispersant PEG-4000.

[0043] The second layer: the mother liquor and sulfuric acid solution are composed of a volume ratio of 1:1.5, wherein the mass concentration of the sulfuric acid solution is 45%, and the mother liquor is calculated by weight and consists of 10 kg of water, 2 kg of mesoporous SiO2 nanoparticles, 1 kg of polystyrene-b-poly(2-vinylpyridine) micelles, 0.03 kg of photoinitiator Irgacure 2959, 0.03 kg of antioxidant benzotriazole and 0.3 kg of dispersant PEG-4000.

[0044] The third layer contains only the mother solution, which consists of 10 kg of water, 1 kg of mesoporous SiO2 nanoparticles, 0.8 kg of polystyrene-b-poly(2-vinylpyridine) micelles, 0.01 kg of photoinitiator Irgacure 2959, 0.01 kg of antioxidant benzotriazole, and 0.3 kg of dispersant PEG-4000.

[0045] The preparation method of mesoporous SiO2 nanoparticles is as follows:

[0046] Step 1: Mix 100 g of the template agent hexadecyltrimethylammonium p-toluenesulfonate with 5 L of deionized water, add triethanolamine to adjust the pH to 9.5, heat to 78°C and stir until clear;

[0047] Step 2: Add 229 g of tetraethyl orthosilicate at a rate of 0.5 ml / min, with a molar ratio of hexadecyltrimethylammonium p-toluenesulfonate to tetraethyl orthosilicate of 1:5, and stir at 300 rpm for 2 h to obtain a white precipitate;

[0048] Step 3: Filter, wash, dry and weigh. Disperse the precipitate in an ethanol aqueous solution, add resorcinol and formaldehyde, stir for 10 hours, and then filter and wash again. The mass ratio of resorcinol to precipitate is 0.6:1, and the molar ratio of resorcinol to formaldehyde is 1:2. Heat to 550°C at a heating rate of 2°C / min under nitrogen protection and calcine for 1.5 hours to obtain mesoporous SiO2 nanoparticles.

[0049] The obtained mesoporous SiO2 nanoparticles were subjected to dynamic light scattering, and the detected hydrodynamic diameter was found to be in line with 50 - 200 nm. Through nitrogen adsorption - desorption detection, its BET specific surface area > 500 m 2 / g, and the pore size distribution was in line with 3.2 - 7.6 nm.

[0050] The preparation method of the polystyrene - b - poly(2 - vinylpyridine) micelles is as follows:

[0051] Dissolve 1 g of polystyrene - b - poly(2 - vinylpyridine) powder in a mixed solvent of 50 ml of THF and methanol with a volume ratio of 95:5. After ultrasonic treatment at 150 W for 20 min, perform evaporation treatment at 25 °C and a humidity ≤ 30% environment for 12 h to form a micelle film. After vacuum drying, polystyrene - b - poly(2 - vinylpyridine) micelles are obtained, where the molecular weight of the polystyrene - b - poly(2 - vinylpyridine) powder is 28000 g / mol.

[0052] Electrolyte preparation:

[0053] Mix the mother liquor of the first - layer colloidal electrolyte raw material and sulfuric acid solution, then perform ultrasonic dispersion, and then pour it into the battery without exceeding the top of the electrode group. Place it in a 15 °C water bath and perform the first charge formation under ultraviolet light irradiation at 365 nm and 10 mW / cm 2 When the state of charge (SOC) reaches 95%, extract the free acid under vacuum negative pressure to obtain the first colloidal electrolyte;

[0054] Mix the mother liquor of the second - layer colloidal electrolyte raw material and sulfuric acid solution, then perform ultrasonic dispersion, and then pour it into the battery to cover the top of the electrode group without exceeding the bus bar. First, perform centrifugation at 8000×g for 10 min at 15 °C, and then perform centrifugation at 12000×g for 20 min. The centrifugal force during the above - mentioned centrifugation process is perpendicular to the axis of the tubular battery. Then place it in a 15 °C water bath and perform the first charge formation. During the charging process, perform pulsed ultraviolet irradiation, irradiate for 5 s and stop for 10 s. When the SOC reaches 95%, extract the free acid under vacuum negative pressure to obtain the second colloidal electrolyte;

[0055] Ultrasonically disperse the mother liquor of the third - layer colloidal electrolyte raw material, then pour it into the battery to cover the bus bar, and place it in a 45 °C water bath to perform the first charge formation to obtain the third colloidal electrolyte.

[0056] Example 2

[0057] Based on Example 1, the mesoporous SiO2 nanoparticles used in this example were not subjected to carbon coating treatment. Specifically, in step three, after filtration and washing, directly heat it to 550 °C at a rate of 2 °C / min under nitrogen protection and perform calcination treatment for 1.5 h to obtain mesoporous SiO2 nanoparticles.

[0058] The obtained mesoporous SiO2 nanoparticles were subjected to dynamic light scattering, and the detected hydrated particle size was in line with 50 - 200 nm. Nitrogen adsorption - desorption detection showed that its BET specific surface area > 500 m 2 / g, and the pore size distribution was in line with 3.2 - 7.6 nm.

[0059] Other conditions remain unchanged.

[0060] Example 3

[0061] Based on Example 1, in this example, after the second - layer perfusion, centrifugation was not carried out. The specific steps are as follows:

[0062] After mixing the mother liquor of the second - layer colloidal electrolyte raw material and the sulfuric acid solution, ultrasonic dispersion was carried out, and then it was poured into the battery and covered the top of the electrode group, not exceeding the bus bar. Then it was placed in a 15°C water bath for a primary charge formation. During the charging process, pulsed ultraviolet irradiation was carried out, irradiating for 5 s and stopping for 10 s. When the SOC reached 95%, free acid was extracted under vacuum negative pressure to obtain the second colloidal electrolyte.

[0063] Other conditions remain unchanged.

[0064] Example 4

[0065] Based on Example 3, the mesoporous SiO2 nanoparticles used in this example were not subjected to carbon coating treatment. Specifically, in step three, after filtration and washing, it was directly calcined under nitrogen protection by heating to 550°C at a rate of 2°C / min for 1.5 h to obtain mesoporous SiO2 nanoparticles.

[0066] The obtained mesoporous SiO2 nanoparticles were subjected to dynamic light scattering, and the detected hydrated particle size was in line with 50 - 200 nm. Nitrogen adsorption - desorption detection showed that its BET specific surface area > 500 m 2 / g, and the pore size distribution was in line with 3.2 - 7.6 nm.

[0067] Other conditions remain unchanged.

[0068] Comparative Example 1

[0069] This comparative example did not adopt a multi - layer electrolyte structure

[0070] It only adopted the formulation of the second - layer electrolyte in Example 1.

[0071] The preparation method includes:

[0072] After mixing the mother liquor of the second - layer colloidal electrolyte raw material and the sulfuric acid solution, ultrasonic dispersion was carried out, and then it was poured into the battery until it covered the bus bar, placed in a 15°C water bath, and irradiated at 365 nm, 10 mW / cm 2One charge formation is carried out under ultraviolet light irradiation. When the state of charge (SOC) reaches 95%, free acid is extracted under vacuum negative pressure to obtain the electrolyte.

[0073] Comparative Example 2

[0074] This comparative example uses conventional gas-phase SiO₂ nanoparticles (average particle size 20 nm, specific surface area 220 m 2 / g) and adopts a uniform electrolyte structure.

[0075] Specifically, the electrolyte raw material consists of a mother liquor and a sulfuric acid solution with a volume ratio of 1:1.5. The mass concentration of the sulfuric acid solution is 45%. The mother liquor, calculated by weight, consists of 10 kg of water, 2 kg of gas-phase SiO₂ nanoparticles, 0.03 kg of antioxidant benzotriazole, and 0.3 kg of dispersant PEG-4000.

[0076] The preparation method includes:

[0077] After mixing the electrolyte raw materials, ultrasonic dispersion is carried out, and then it is poured into the battery and covers the bus bar. It is placed in a 15°C water bath, and one charge formation is carried out. When the SOC reaches 95%, free acid is extracted under vacuum negative pressure to obtain the electrolyte.

[0078] Comparative Example 3

[0079] Based on Example 1, this comparative example uses an electrolyte raw material system without polystyrene-b-poly(2-vinylpyridine) micelles, and each layer of polystyrene-b-poly(2-vinylpyridine) micelles is equally mass-replaced with PEG-4000. Others remain unchanged.

[0080] Cyclic tests and ion conductivity tests are carried out on different tubular gel batteries prepared by the above-mentioned schemes. Among them, the cyclic tests are carried out according to the standard of GB / T 22473-2008. The cyclic tests are charged and discharged at 1C at 25°C, and the cut-off voltage is 2.0V - 2.4V. The ion conductivity is measured by the four-electrode method.

[0081] The test results are specifically shown in the following table:

[0082]

[0083] It can be seen from the data of Example 1 and Comparative Example 1 that the use of a hierarchical structure design has better adaptability to the plate expansion stress than a single-layer structure. The cycle life of the battery is greatly improved, and it is beneficial to reduce the crack propagation. By using a low-acid mother liquor to seal the bus bar through the hierarchical structure, the acid mist oxidation is greatly inhibited.

[0084] From the data comparison between Example 1 and Example 2, it can be seen that the mesoporous structure of the mesoporous silica after carbon coating treatment is better protected, and the acid etching rate drops significantly. Moreover, after setting the carbon coating structure, the compressive strength is also greatly improved, which should be due to the introduction of the carbon interface forming a mechanical interlock.

[0085] From the data comparison between Example 1 and Example 3, it can be seen that through centrifugation treatment, the deviation of the colloidal filling density drops significantly, and the basic crack rate is also greatly reduced. At the same time, a more uniform gel network is beneficial to reducing the ion migration resistance, thus greatly improving the ionic conductivity.

[0086] From the data comparison between Example 1 and Example 4, it can be seen that through the carbon coating treatment on the surface of silica, not only the acid etching problem of silica is significantly reduced, but also the carbon coating and micelles play a certain composite toughening effect, thus improving the compressive effect.

[0087] From the data comparison between Example 1 and Comparative Example 2, it can be seen that compared with conventional fumed silica, the mesoporous channels are beneficial to providing a directional transmission path, resulting in a huge improvement in the performance of ionic conductivity, and the acid storage capacity is also larger than that of conventional fumed silica.

[0088] From the data comparison between Example 1 and Comparative Example 3, it can be seen that after the micelles are missing, the dynamic cross-linked network formed by mesoporous silica and micelles is missing, the compressive strength drops significantly, and the ionic conductivity also drops significantly. This shows that after the micelles are protonated, they play a certain auxiliary role in the migration of ions. Moreover, the crack rate of the electrode plate also increases significantly, indicating that after the micelles are missing, the gel network cannot adapt to the expansion of the electrode plate during the cyclic charging process, thus generating stress concentration.

[0089] The above is only the preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A non-uniform electrolyte for a tubular battery, characterized in that, It comprises a first colloidal electrolyte, a second colloidal electrolyte and a third colloidal electrolyte, wherein the three electrolytes are respectively distributed in the interior of the pole group, between the periphery of the pole group and the bus, and the area above the bus of the tubular battery, wherein the first colloidal electrolyte, the second colloidal electrolyte and the third colloidal electrolyte all comprise a mother liquor, wherein the mother liquor comprises, by weight, 10 parts of water, 1.5-2.5 parts of mesoporous SiO2 nanoparticles, 0.8-1.2 parts of polystyrene-b-poly(2-vinylpyridine) micelles, 0.01-0.05 parts of a photoinitiator, 0.01-0.05 parts of an antioxidant and 0.3 parts of a dispersant, and the first colloidal electrolyte and the second colloidal electrolyte also comprise a sulfuric acid solution; The first colloidal electrolyte is composed of a mother liquid and a sulfuric acid solution in a volume ratio of 1:1.2, wherein the mass concentration of the sulfuric acid solution is 38%, and the mother liquid, calculated by weight, includes: 10 parts of water, 2-2.5 parts of mesoporous SiO2 nanoparticles, 1-1.2 parts of polystyrene-b-poly(2-vinylpyridine) micelles, 0.01-0.05 parts of photoinitiator, 0.01-0.05 parts of antioxidant and 0.3 parts of dispersant; The second colloidal electrolyte is composed of a mother liquid and a sulfuric acid solution in a volume ratio of 1:1.5, wherein the mass concentration of the sulfuric acid solution is 45%, and the mother liquid, calculated by weight, includes: 10 parts of water, 1.5-2 parts of mesoporous SiO2 nanoparticles, 0.8-1 parts of polystyrene-b-poly(2-vinylpyridine) micelles, 0.01-0.05 parts of photoinitiator, 0.01-0.05 parts of antioxidant and 0.3 parts of dispersant; The third colloidal electrolyte is composed of a mother liquid, which is calculated by weight and includes: 10 parts of water, 1 part of mesoporous SiO2 nanoparticles, 0.8 parts of polystyrene-b-poly(2-vinylpyridine) micelles, 0.01-0.05 parts of photoinitiator, 0.01-0.05 parts of antioxidant and 0.3 parts of dispersant; The preparation method of mesoporous SiO2 nanoparticles comprises: Step 1: Mix the template agent hexadecyltrimethylammonium p-toluenesulfonate with deionized water, adjust the pH to 9-10 with triethanolamine, heat to 75-85°C and stir until clear; Step 2: Add ethyl orthosilicate, keep warm and stir for 1.5-2.5 hours to obtain a white precipitate; Step 3, filtering, washing, and calcining at 500-600°C for 1-2h to obtain mesoporous SiO2 nanoparticles; The obtained mesoporous SiO2 nanoparticles have a particle size of 50-200 nm and a pore size of 3.2-7.6 nm; The preparation method of polystyrene-b-poly(2-vinylpyridine) micelles comprises: Dissolve 1 g of polystyrene-b-poly(2-vinylpyridine) powder in a mixed solvent of 50 ml of THF and methanol with a volume ratio of 95:

5. After ultrasonic treatment at 150 W for 20 min, perform evaporation treatment at 20 - 30 °C and humidity ≤ 30% for 12 h to form a micelle film. After vacuum drying, obtain polystyrene-b-poly(2-vinylpyridine) micelles, where the molecular weight of the polystyrene-b-poly(2-vinylpyridine) powder is 25000 - 30000 g / mol.

2. The non-uniform electrolyte of the tubular battery according to claim 1, wherein In step three, after filtration and washing, before the calcination treatment at 500 - 600 °C for 1 - 2 h, it also includes dispersing the precipitate in an ethanol aqueous solution, adding resorcinol and formaldehyde, stirring for 8 - 12 h, and then filtering and washing again.

3. The non-uniform electrolyte of the tubular battery according to claim 1, wherein The dispersant is PEG-4000, the photoinitiator is Irgacure 2959, and the antioxidant is benzotriazole.

4. The preparation method of the tubular battery non-uniform electrolyte according to any one of claims 1-3, characterized in that, It includes the following steps: Step 1: Mix the mother liquor of the first colloidal electrolyte raw material and the sulfuric acid solution, perform ultrasonic dispersion, then pour it into the battery not exceeding the top of the electrode group, place it in a water bath at 15 - 20 °C, and perform the first charge formation under ultraviolet light irradiation. When the state of charge (SOC) reaches 95%, vacuum negative pressure is used to extract free acid to obtain the first colloidal electrolyte; Step 2: Mix the mother liquor of the second colloidal electrolyte raw material and the sulfuric acid solution, perform ultrasonic dispersion, then pour it into the battery to cover the top of the electrode group and not exceed the bus bar, place it in a water bath at 15 - 20 °C, perform the first charge formation, and perform pulsed ultraviolet irradiation during the charge and discharge process. When the SOC reaches 95%, vacuum negative pressure is used to extract free acid to obtain the second colloidal electrolyte; Step 3: Ultrasonically disperse the mother liquor of the third colloidal electrolyte raw material, then pour it into the battery to cover the bus bar, place it in a water bath at 45 - 60 °C, and perform the first charge formation to obtain the third colloidal electrolyte.

5. The preparation method according to claim 4, characterized in that, In step two, after pouring it into the battery to cover the top of the electrode group and before the water bath heat preservation, it also includes centrifuging at 8000×g for 10 min at 15 - 20 °C, and then centrifuging at 12000×g for 20 min.

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