Lead-sodium battery

Abstract

The invention discloses a lead-sodium storage battery in the technical field of storage batteries, which comprises a positive plate, a negative plate and electrolyte: the positive plate comprises positive lead plaster and a positive grid, and the positive lead plaster comprises 100 parts of lead oxide powder, 6-12 parts of sulfuric acid, 5-15 parts of deionized water, 0.05-0.1 part of short fiber or conductive graphite fiber and 0.4-2 parts of mixture; the negative plate comprises negative lead paste and a negative plate grid, and the negative lead paste comprises 100 parts of lead oxide powder, 6-12 parts of sulfuric acid and 5-15 parts of deionized water; 0.05-0.1 part of short fibers or conductive graphite fibers and 1-10 parts of a mixture; and the electrolyte comprises 0.01-0.6 part of silicon dioxide, 30-50 parts of 98% anhydrous concentrated sulfuric acid, 2-7 parts of a sodium compound, 0.1-0.15 part of stannous mono-sulphate, 0.5-0.8 part of phosphoric acid, 1-2 parts of vanillin and 40-60 parts of deionized water. According to the lead-acid storage battery electrolyte, good low-temperature resistance of the lead-acid storage battery can be effectively realized, and the service life of the storage battery is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of storage batteries, and particularly relates to a lead-sodium storage battery. Background Art

[0002] Lead-acid storage batteries have a history of more than 160 years, and the production process is relatively mature. However, the disadvantages of lead-acid storage batteries, such as poor low-temperature performance and short service life, limit the application of storage batteries in some scenarios. In the national standards and industry standards of lead-acid storage batteries, the lowest operating temperature of lead-acid storage batteries is -30°C. In actual use, the low temperature can even reach below -40°C, and the charging acceptance ability of the storage battery becomes poor and the cycle life is short under low-temperature conditions. Therefore, a lead-sodium storage battery is needed to solve the above problems. Summary of the Invention

[0003] In view of the deficiencies in the prior art, the present invention provides a lead-sodium battery, which can effectively achieve good low-temperature resistance of lead-acid storage batteries and extend the service life of storage batteries.

[0004] The object of the present invention is achieved as follows: A lead-sodium battery includes a positive electrode plate, a negative electrode plate, and an electrolyte. The positive electrode plate includes positive electrode lead paste and a positive electrode grid. The positive electrode lead paste includes the following weight components: 100 parts of lead oxide powder, 6-10 parts of sulfuric acid, 14-24 parts of deionized water, 0.05-0.07 parts of short fibers, 2-8 parts of lead dioxide, 1-2 parts of tribasic lead sulfate, 0.5-1.5 parts of calcium sulfate, 0.05-0.15 parts of stannous sulfate, 0.05-0.15 parts of antimony trioxide, 0.5-1 part of carbon black, 0.1-0.2 parts of sodium carboxymethyl cellulose, and 0.1-0.5 parts of mixed carbon materials. The negative electrode plate includes negative electrode lead paste and a negative electrode grid. The negative electrode lead paste includes the following weight components: 100 parts of lead oxide powder, 6-12 parts of sulfuric acid, 11-20 parts of deionized water, 0.05-0.07 parts of short fibers, 0.3-0.9 parts of humic acid, 0.1-0.3 parts of sodium lignosulfonate, 0.06-1 part of silicon dioxide, 0.8-1.6 parts of barium sulfate, 0.1-0.5 parts of sodium sulfate, 0.04-0.1 parts of ammonium persulfate, 0.06-0.1 parts of vanillin, 0.2-0.4 parts of tannin extract, and 0.2-0.4 parts of mixed carbon materials. The electrolyte includes the following weight parts of materials: 0.2-0.6 parts of silicon dioxide content, 30-50 parts of 98% anhydrous concentrated sulfuric acid, 2-4 parts of sodium compounds, 0.05-0.15 parts of stannous sulfate, 0.5-0.7 parts of phosphoric acid, 1-2 parts of vanillin, and 60-100 parts of deionized water.

[0005] Furthermore, the oxidation degree of the lead powder is 72-80%, the particle size is ≤5 μm, and the particle size of the silicon dioxide particles is ≤30 μm; the mixed carbon material includes graphite, acetylene black, and graphene; the sodium compound is one or more of sodium stannous citrate, sodium stannate, sodium tetraborate, sodium sulfate, sodium silicate, sodium sulfide, sodium polyacrylate, sodium tripolyphosphate, sodium dimercaptosuccinate, sodium dodecylbenzenesulfonate, sodium perfluoroalkylsulfonate, sodium polyaspartate, and disodium nitrilotriacetate.

[0006] Furthermore, the preparation method of the positive electrode lead paste includes the following steps: S1. According to the ratio, premix calcium sulfate, stannous sulfate, and antimony trioxide to obtain mixture A; S2. According to the ratio, add lead dioxide and tribasic lead sulfate to a paste mixer and dry-mix with lead oxide powder; S3. Add mixture A, short fibers in proportion, and the mixed carbon material to the paste mixer and dry-mix with the product of step 2; S4. Add deionized water and sulfuric acid to the paste mixer respectively for water mixing and acid mixing to obtain the positive electrode lead paste.

[0007] Furthermore, when premixing in S1, a ball mill is used, the rotation speed of the ball mill is 200-300 rpm, and the premixing time is 0.5-1 h; the dry-mixing time in S2 is 1-5 min, and the dry-mixing time in step 3 is 5-10 min; in S4, water mixing and acid mixing are carried out with deionized water and sulfuric acid respectively in the paste mixer, the water addition time is 1-3 min, the water mixing time is 5-10 min, the density of the sulfuric acid is 1.4 g / cm 3 , the acid addition time is 15-20 min, and the acid mixing time is 5-10 min.

[0008] Furthermore, the preparation method of the positive electrode plate includes the following steps: S1. Prepare an aqueous solution of carbon black according to the following weight components: 0.5-1 part of carbon black, 5-10 parts of deionized water, and 0.1-0.2 part of sodium carboxymethyl cellulose; S2. Uniformly coat the positive electrode lead paste on the positive electrode alloy grid; S3. Spray the aqueous solution of carbon black on the surface of the lead paste, and after acid showering and surface drying, carry out a curing treatment to obtain the positive electrode plate.

[0009] Furthermore, the sodium carboxymethyl cellulose is a thickening agent, and the dosage of the aqueous solution of carbon black is sprayed on both sides according to 10-30 mg per gram of lead paste, the density of the acid shower is 1.15 g / cm 3 , the surface drying temperature is 120-140 °C; the curing and drying treatment process is as follows: Step a. The relative humidity is 95-100%, the temperature is 65-70 °C, and the controlled duration is 4-5 h; Step b: The relative humidity is 85 - 90%, the temperature is 70 - 76°C, and the controlled duration is 6 - 8 h; Step c: The relative humidity is 85 - 90%, the temperature is 50 - 55°C, and the controlled duration is 16 - 18 h; Step d: The relative humidity is 5 - 20%, the temperature is 75 - 80°C, and the controlled duration is 30 - 32 h.

[0010] Furthermore, the preparation method of the negative electrode lead paste includes the following steps: S1: According to the proportion, add humic acid and sodium lignosulfonate to deionized water and stir to dissolve. After adding silica particles in a set proportion to the prepared solution, carry out decompression and pressurization, fully mix and then perform drying treatment to obtain mixture B; S2: Add mixture B, barium sulfate and sodium sulfate in accordance with the proportion to a ball mill for mixing to obtain mixture C; S3: According to the proportion, add quebracho extract to deionized water to dissolve and prepare a quebracho extract solution; S4: After adding mixture C, short fibers, ammonium persulfate, vanillin, and mixed carbon materials to a paste mixer and dry - mixing with lead powder, add the quebracho extract solution, the remaining deionized water, and sulfuric acid respectively for water mixing and acid mixing to prepare the negative electrode lead paste.

[0011] Furthermore, in S1, the stirring time for stirring and dissolving > 10 min. After adding silica particles in a set proportion to the prepared solution, decompress to - 0.1 - 0.3 MPa and then pressurize to 0.1 MPa, fully mix and then perform drying treatment, the drying temperature ≥ 60°C and the time > 5 h; in S2, the ball mill rotation speed is 200 - 300 rpm and the mixing time is 0.5 - 1 h; in S4, the dry - mixing time is 5 - 12 min, and perform water mixing and acid mixing with the quebracho extract solution, the remaining deionized water, and sulfuric acid respectively. The water - adding time is 1 - 3 min, the water - mixing time is 5 - 10 min, the density of the sulfuric acid is 1.4 g / cm 3 , the acid - adding time is 15 - 20 min, and the acid - mixing time is 5 - 10 min.

[0012] Furthermore, the preparation method of the electrolyte includes the following steps: S1: Add deionized water in accordance with the proportion to a acid - preparation tank. Under the condition of continuous stirring, slowly add 98% anhydrous sulfuric acid. After the addition is completed, wait for the solution temperature to drop to room temperature; S2: Mix and modify sodium compounds, stannous sulfate, phosphoric acid, and vanillin in accordance with the proportion to obtain mixture D; S3: Add mixture D to deionized water, heat and stir. After heating to the set temperature, stop heating, continue to stir evenly and then wait for the solution to cool to room temperature to obtain mixed liquid E; S4. Add deionized water to the colloid disperser, then add fumed silica and disperse at high speed to form a uniform colloidal solution F. S5. Slowly add the mixed solution E and the colloidal solution F in proportion to the sulfuric acid solution prepared in S1 and stir to obtain the electrolyte.

[0013] Furthermore, in S2, the grinding and modification speed is not less than 200 rpm and the time is not less than 0.5 h; in S3, the temperature is raised to 48 - 52 °C; in S4, the high-speed dispersion is carried out for 1 - 3 h; in S5, the stirring speed is not less than 1500 rpm and the time is not less than 20 min.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: In the positive electrode lead paste of the present invention, calcium sulfate, stannous sulfate, and antimony trioxide are premixed to obtain a mixture A, achieving physical embedding. The powder particles are of uniform size, ensuring that the mixture after grinding can be evenly distributed in the active material during pasting. At the same time, the particles of calcium sulfate become smaller, reducing its impact on the formation efficiency, thereby exerting its role in the low-temperature performance of the battery; lead dioxide replaces red lead, solving the problems brought by the purity of red lead to the battery and improving the formation efficiency; lead dioxide and tetrabasic lead sulfate are preferentially dry-mixed with lead oxide powder, effectively achieving uniform distribution; the carbon black aqueous solution is sprayed on the surface of the positive electrode plate, which can effectively increase the initial conductivity of the electrode plate, and the high-current discharge performance at low temperature is more obvious.

[0015] In the negative electrode lead paste of the present invention, the stability of the additive and the mixing uniformity are effectively improved. The mixture B has a more stable structure. Humic acid and sodium lignosulfonate are immersed in the silica particles through pressure increase and decrease, solving the instability problem of sodium lignosulfonate. During the charge and discharge of the battery, sodium lignosulfonate in the mixture B is not easily dissolved. At the same time, under the action of humic acid and silica, it has better low-temperature performance and also has an excellent effect on inhibiting hydrogen evolution at the negative electrode; the mixed carbon material can construct a better conductive network, improving the conductivity and the activity of ion migration at low temperature; further, the mixture B, barium sulfate, and sodium sulfate are added to a ball mill for mixing to obtain a mixture C, achieving physical embedding. The powder particles are of uniform size, ensuring that the mixture after grinding can be evenly distributed in the active material during pasting, enabling the performance of each component material in the mixture to be fully exerted. Under the combined action of other additives such as ammonium persulfate, vanillin, and tannin extract, the stability, low-temperature performance, and service life of the battery are improved.

[0016] In the electrolyte of the present invention, by adding a mixture containing sodium, the viscosity of the electrolyte can be reduced, the ion migration efficiency can be enhanced, thereby reducing the increase in internal resistance in a low-temperature environment, and improving the discharge capacity and charge acceptance ability of the battery at low temperatures. A compound of sodium, stannous sulfate, phosphoric acid, and vanillin are mixed and modified to obtain mixture D, which is a composite additive with a smaller particle structure. Then, it is heated and stirred in deionized water. After heating to the set temperature, heating is stopped, and stirring is continued until uniform. After the solution is cooled to room temperature, mixture E is obtained. The substances in mixture E are more dispersed, improving the uniformity after adding sulfuric acid. The freezing point of colloid solution F is lower than that of the sulfuric acid electrolyte, which can improve certain low-temperature performance, effectively prevent the electrolyte from stratifying, ensure that the electrolyte density of the upper and lower layers of the battery is consistent, and avoid the problem of shortened battery life caused by concentration difference in traditional lead-acid batteries. With the synergistic effect of mixture E and colloid solution F, the low-temperature cycle stability can be further improved. More preferably, by adding a compound of sodium, the performance of the electrolyte can be improved, the charge balance efficiency inside the battery can be enhanced, the ion transport path can be optimized, thereby stabilizing the voltage and increasing the overall capacity.

[0017] In summary, through the design improvement of the process, the present invention is beneficial to maintaining the cycle capacity of the battery and the low-temperature performance of the battery, thus effectively realizing the advantages of good low-temperature resistance of the storage battery and extending the service life of the storage battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] 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 the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the provided drawings.

[0019] Figure 1 It is a schematic diagram of discharge at low temperature for the embodiment and comparative example of the present invention.

[0020] Figure 2 It is a schematic diagram of discharge at normal temperature for the embodiment and comparative example of the present invention.

[0021] Figure 3 It is a cycle life curve graph for the embodiment and comparative example of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of 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.

[0023] Example 1 A lead - sodium battery includes a positive electrode plate, a negative electrode plate, and an electrolyte; the positive electrode plate includes positive electrode paste and a positive electrode grid, and the negative electrode plate includes negative electrode paste and a negative electrode grid.

[0024] Furthermore, the preparation method of the positive electrode plate includes: S1. Prepare the positive electrode paste.

[0025] The positive electrode paste includes 100 parts of lead oxide powder, 6 parts of sulfuric acid, 14 parts of deionized water, 0.05 part of short fiber, 2 parts of lead dioxide, 1 part of tribasic lead sulfate, 0.5 part of calcium sulfate, 0.05 part of stannous sulfate, 0.05 part of antimony trioxide, 0.5 part of carbon black, 0.1 part of sodium carboxymethyl cellulose, and 0.1 part of mixed carbon material.

[0026] Specifically, the oxidation degree of the lead oxide powder is 72%, the particle size is 2 - 3μm, and the mixed carbon material is 0.05 of graphite, 0.025 of acetylene black, and 0.025 of graphene.

[0027] The specific steps are as follows: S1 - 1. According to the above ratio, premix 0.5 part of calcium sulfate, 0.05 part of stannous sulfate, and 0.05 part of antimony trioxide through a ball mill, with the ball mill rotating at 200 rpm and the premixing time being 1 h; S1 - 2. According to the above ratio, add 2 parts of lead dioxide and 1 part of tribasic lead sulfate to a paste mixer and dry - mix with the lead oxide powder for 1 min; S1 - 3. Add the product of S1 - 1, 0.05 part of short fiber, and 0.1 part of mixed carbon material to the paste mixer and dry - mix with the lead powder for 5 min; S1 - 4. In the paste mixer, conduct water mixing and acid mixing with deionized water and sulfuric acid respectively. The water - adding time is 1 min, the water - mixing time is 5 min, the density of sulfuric acid is 1.4 g / cm3, the acid - adding time is 15 min, and the acid - mixing time is 5 min, thereby obtaining the positive electrode paste.

[0028] S2. Prepare the positive electrode plate. The positive electrode plate includes positive electrode paste and a positive electrode grid.

[0029] Furthermore, the steps for preparing the positive electrode plate are as follows: Step 2 - 1. Prepare an aqueous solution of carbon black, with the following weight components: 0.5 part of carbon black, 5 parts of deionized water, and 0.1 part of thickener sodium carboxymethyl cellulose; Step 2 - 2. Evenly apply the positive electrode paste prepared in S1 onto the positive electrode alloy grid; Step 2-3: Spray an aqueous solution of carbon black on the surface of the lead paste. After acid drenching and surface drying, perform a curing treatment to obtain the positive electrode plate. The dosage of the aqueous solution of carbon black is 10 mg per gram of lead paste for spraying on both sides. The acid drenching density is 1.15 g / cm3, and the surface drying temperature is 120°C.

[0030] Specifically, the curing and drying treatment process is as follows: Step 1: The relative humidity is 95 - 100%, the temperature is 70°C, and the controlled duration is 4 h; Step 2: The relative humidity is 85 - 90%, the temperature is 76°C, and the controlled duration is 8 h; Step 3: The relative humidity is 85 - 90%, the temperature is 55°C, and the controlled duration is 18 h; Step 4: The relative humidity is 5 - 20%, the temperature is 80°C, and the controlled duration is 30 h.

[0031] Furthermore, the negative electrode lead paste includes the following materials in parts by weight: 100 parts of lead oxide powder, 6 parts of sulfuric acid, 11 parts of deionized water, 0.05 part of short fiber, 0.3 part of humic acid, 0.1 part of sodium lignosulfonate, 0.06 part of silicon dioxide, 0.8 part of barium sulfate, 0.1 part of sodium sulfate, 0.04 part of ammonium persulfate, 0.06 part of vanillin, 0.2 part of tannin extract, and 0.2 part of mixed carbon material.

[0032] Specifically, the oxidation degree of the lead powder is 72%, the particle size is 3 - 4 μm, the silicon dioxide particles are ≤30 μm, and the carbon material is 0.1 part of acetylene black, 0.05 part of carbon black, and 0.05 part of graphene.

[0033] Furthermore, the preparation method of the negative electrode lead paste includes the following steps: S1: According to the ratio, add 0.3 part of humic acid and 0.1 part of sodium lignosulfonate to 1 part of deionized water and stir to dissolve. The stirring time is 20 min. After adding 0.06 part of silicon dioxide particles to the prepared solution, reduce the pressure to -0.1 MPa, and the pressure reduction time is 30 min. Then increase the pressure to 0.1 MPa, fully mix, and perform a drying treatment. The drying temperature is 90°C, and the time is 24 h to obtain mixture B; S2: Add mixture B and 0.8 part of barium sulfate and 0.1 part of sodium sulfate according to the ratio to a ball mill for mixing to obtain mixture C. The rotation speed of the ball mill is 300 rpm, and the premixing time is 0.5 h; S3: Dissolve 0.2 part of tannin extract in 0.8 part of deionized water to prepare a tannin extract solution; S4. Add 0.05 part of short fibers, 0.04 part of ammonium persulfate, 0.06 part of vanillin, 0.1 part of acetylene black, 0.05 part of carbon black, and 0.05 part of graphene to mixture C in a paste mixer and dry-mix for 8 min. Then add 1 part of tannin solution, 9 parts of the remaining deionized water, and 6 parts of sulfuric acid respectively for water mixing and acid mixing. The water addition time is 1.5 min, the water mixing time is 6 min, the density of sulfuric acid is 1.4 g / cm3, the acid addition time is 17 min, and the acid mixing time is 5 min to obtain the negative electrode lead paste.

[0034] Further, the electrolyte includes 0.2 part of silicon dioxide, 30 parts of 98% anhydrous concentrated sulfuric acid, 2 parts of sodium compound, 0.05 part of stannous sulfate, 0.5 part of phosphoric acid, 1 part of vanillin, and 60 parts of deionized water.

[0035] Specifically, the sodium compound is 0.05 part of sodium stannous citrate, 1 part of sodium tetraborate, 0.5 part of sodium sulfate, 0.1 part of sodium polyacrylate, 0.1 part of sodium tripolyphosphate, 0.1 part of sodium dodecylbenzenesulfonate, 0.1 part of sodium polyaspartate, and 0.05 part of disodium nitrilotriacetate.

[0036] Further, the specific preparation steps of the electrolyte are as follows: S1. Add 38 parts of deionized water to the acid mixing tank, and slowly add 30 parts of 98% concentrated sulfuric acid under continuous stirring. After the addition is completed, wait for the solution temperature to drop to room temperature. S2. Mix and modify 2 parts of sodium compound, 0.05 part of stannous sulfate, 0.5 part of phosphoric acid, and 1 part of vanillin according to the ratio at a rotation speed of 200 rpm for 1.5 h to obtain mixture D. S3. Add mixture D to 20 parts of deionized water, heat and stir. Stop heating after the temperature rises to 48 °C, continue to stir evenly, and wait for the solution to cool to room temperature to obtain mixed solution E. S4. Add 2 parts of deionized water to a colloid disperser, then add 0.2 part of fumed silica, and perform high-speed dispersion for 1 h to form a uniform colloidal solution F. S5. Slowly add mixed solution E and colloidal solution F to the sulfuric acid solution prepared in S1 and stir at a stirring speed of 1500 rpm for 30 min to obtain the electrolyte.

[0037] Example 2 A lead-sodium battery includes a positive electrode plate, a negative electrode plate, and an electrolyte; the positive electrode plate includes a positive electrode lead paste and a positive electrode plate grid, and the negative electrode plate includes a negative electrode lead paste and a negative electrode plate grid.

[0038] Further, the preparation method of the positive electrode plate includes: S1. Prepare the positive electrode lead paste.

[0039] The positive electrode lead paste comprises 100 parts of lead oxide powder, 8 parts of sulfuric acid, 19 parts of deionized water, 0.06 part of short fiber, 5 parts of lead dioxide, 1.5 parts of tribasic lead sulfate, 1 part of calcium sulfate, 0.1 part of stannous sulfate, 0.1 part of antimony trioxide, 0.75 part of carbon black, 0.15 part of sodium carboxymethyl cellulose, and 0.3 part of mixed carbon material.

[0040] Specifically, the oxidation degree of the lead oxide powder is 76%, the particle size is 3 - 4 μm, and the mixed carbon material is 0.2 of graphite, 0.05 of acetylene black, and 0.05 of graphene.

[0041] The specific steps are as follows: S1 - 1: According to the above - mentioned ratio, premix 1 part of calcium sulfate, 0.1 part of stannous sulfate, and 0.1 part of antimony trioxide by a ball mill. The rotation speed of the ball mill is 250 rpm, and the premixing time is 45 min. S1 - 2: According to the above - mentioned ratio, add 5 parts of lead dioxide and 1.5 parts of tribasic lead sulfate to a paste mixer and dry - mix with the lead oxide powder for 3 min. S1 - 3: Add the product of S1 - 1, 0.06 part of short fiber, and 0.3 part of mixed carbon material to the paste mixer and dry - mix with the lead powder for 7.5 min. S1 - 4: In the paste mixer, conduct water - mixing and acid - mixing with deionized water and sulfuric acid respectively. The water - adding time is 2 min, the water - mixing time is 7.5 min, the density of sulfuric acid is 1.4 g / cm3, the acid - adding time is 17.5 min, and the acid - mixing time is 7.5 min, thus obtaining the positive electrode lead paste.

[0042] S2: Prepare the positive electrode plate, which includes the positive electrode lead paste and the positive electrode grid.

[0043] Furthermore, the steps for preparing the positive electrode plate are as follows: Step 2 - 1: Prepare an aqueous carbon black solution according to the following weight components: 0.75 part of carbon black, 7.5 parts of deionized water, and 0.15 part of thickening agent sodium carboxymethyl cellulose. Step 2 - 2: Evenly apply the positive electrode lead paste prepared in S1 onto the positive electrode alloy grid. Step 2 - 3: Spray the aqueous carbon black solution on the surface of the lead paste. After acid - spraying and surface drying, conduct a curing treatment to obtain the positive electrode plate. The dosage of the aqueous carbon black solution is 20 mg per gram of lead paste for spraying on both sides. The density of acid - spraying is 1.15 g / cm3, and the surface drying temperature is 130 °C.

[0044] Specifically, the curing and drying treatment process is as follows: Step 1: The relative humidity is 95 - 100%, the temperature is 67 °C, and the controlled duration is 4.5 h. Step 2: The relative humidity is 85 - 90%, the temperature is 73 °C, and the controlled duration is 7 h. Step 3: The relative humidity is 85 - 90%, the temperature is 53°C, and the control duration is 17 h; Step 4: The relative humidity is 5 - 20%, the temperature is 78°C, and the control duration is 31 h.

[0045] Furthermore, the negative electrode lead paste includes the following materials in parts by weight: 100 parts of lead oxide powder, 9 parts of sulfuric acid, 15 parts of deionized water, 0.06 part of short fiber, 0.6 part of humic acid, 0.2 part of sodium lignosulfonate, 0.08 part of silicon dioxide, 1.2 parts of barium sulfate, 0.3 part of sodium sulfate, 0.07 part of ammonium persulfate, 0.08 part of vanillin, 0.3 part of tannin extract, and 0.3 part of mixed carbon materials.

[0046] Specifically, the oxidation degree of the lead powder is 74%, the particle size is 4 - 5 μm, the silicon dioxide particles are ≤30 μm, and the carbon materials are 0.2 part of acetylene black, 0.05 part of carbon black, and 0.05 part of graphene.

[0047] Furthermore, the preparation method of the negative electrode lead paste includes the following steps: S1: According to the proportion, add 0.6 part of humic acid and 0.2 part of sodium lignosulfonate to 2 parts of deionized water and stir to dissolve. The stirring time is 20 min. After adding 0.08 part of silicon dioxide particles to the prepared solution, reduce the pressure to -0.1 MPa, and the pressure reduction time is 45 min. Then increase the pressure to 0.1 MPa, fully mix and then perform drying treatment. The drying temperature is 75°C and the time is 36 h to obtain mixture B; S2: Add 1.2 parts of barium sulfate and 0.3 part of sodium sulfate in proportion to mixture B and add them to a ball mill for mixing and grinding to obtain mixture C. The rotation speed of the ball mill is 200 rpm and the premixing time is 1 h; S3: Dissolve 0.3 part of tannin extract in 1.2 parts of deionized water to prepare a tannin extract solution; S4: Add mixture C, 0.06 part of short fiber, 0.07 part of ammonium persulfate, 0.08 part of vanillin, 0.2 part of acetylene black, 0.05 part of carbon black, and 0.05 part of graphene to a paste mixer and dry - mix with lead powder. The dry - mixing time is 6 min. Then add 1.5 parts of the tannin extract solution, the remaining 11.8 parts of deionized water, and 9 parts of sulfuric acid respectively for water mixing and acid mixing. The water - adding time is 1 min, the water - mixing time is 6 min, the density of sulfuric acid is 1.4 g / cm3, the acid - adding time is 16 min, and the acid - mixing time is 6 min, thereby obtaining the negative electrode lead paste.

[0048] Furthermore, the electrolyte includes 0.4 part of silicon dioxide content, 40 parts of 98% anhydrous concentrated sulfuric acid, 3 parts of sodium compound, 0.1 of stannous sulfate, 0.6 part of phosphoric acid, 1.5 parts of vanillin, and 80 parts of deionized water.

[0049] Specifically, the sodium compound is 0.1 part of sodium stannous citrate, 1.5 parts of sodium tetraborate, 1 part of sodium sulfate, 0.05 part of sodium silicate, 0.15 part of sodium polyacrylate, 0.15 part of sodium polyaspartate, and 0.05 of disodium nitrilotriacetate.

[0050] Furthermore, the specific preparation steps of the electrolyte are as follows: S1. Add 46 parts of deionized water to the acid mixing tank. Under continuous stirring, slowly add 40 parts of 98% concentrated sulfuric acid. After the addition is complete, wait for the solution temperature to drop to room temperature. S2. According to the ratio, mix and modify 3 parts of the sodium compound, 0.1 part of stannous sulfate, 0.6 part of phosphoric acid, and 1.5 parts of vanillin at a rotation speed of 250 rpm for 1 hour to obtain mixture D. S3. Add mixture D to 30 parts of deionized water, heat and stir. Stop heating after the temperature rises to 50°C, continue to stir evenly, and wait for the solution to cool to room temperature to obtain mixed solution E. S4. Add 4 parts of deionized water to the colloid disperser, then add 0.4 part of fumed silica, and perform high-speed dispersion for 2 hours to form a uniform colloidal solution F. S5. Slowly add mixed solution E and colloidal solution F to the sulfuric acid solution prepared in S1 and stir at a stirring speed of 2000 rpm for 25 minutes to obtain the electrolyte.

[0051] Example 3 A lead-sodium battery includes a positive electrode plate, a negative electrode plate, and an electrolyte; the positive electrode plate includes positive electrode lead paste and a positive electrode plate grid, and the negative electrode plate includes negative electrode lead paste and a negative electrode plate grid.

[0052] Furthermore, the preparation method of the positive electrode plate includes: S1. Prepare the positive electrode lead paste.

[0053] The positive electrode lead paste includes 100 parts of lead oxide powder, 10 parts of sulfuric acid, 24 parts of deionized water, 0.07 part of short fiber, 8 parts of lead dioxide, 2 parts of tribasic lead sulfate, 1.5 parts of calcium sulfate, 0.15 part of stannous sulfate, 0.15 part of antimony trioxide, 1 part of carbon black, 0.2 part of sodium carboxymethyl cellulose, and 0.5 part of mixed carbon material.

[0054] Specifically, the oxidation degree of the lead oxide powder is 80%, the particle size is 4 - 5 μm, and the mixed carbon material is 0.3 of graphite, 0.1 of acetylene black, and 0.1 of graphene.

[0055] The steps for preparing the positive electrode lead paste are as follows: S1-1. According to the above ratio, premix 1.5 parts of calcium sulfate, 0.15 part of stannous sulfate, and 0.15 part of antimony trioxide through a ball mill at a ball mill rotation speed of 300 rpm for 0.5 hour. S1-2. According to the above ratio, add 8 parts of lead dioxide and 2 parts of tribasic lead sulfate into the paste mixer and dry mix with lead oxide powder for 5 min; S1-3. Add the product of S1-1, 0.07 part of short fiber, and 0.5 part of mixed carbon material into the paste mixer and dry mix with lead powder for 10 min; S1-4. Conduct water mixing and acid mixing with deionized water and sulfuric acid respectively in the paste mixer. The water addition time is 3 min, the water mixing time is 10 min, the density of sulfuric acid is 1.4 g / cm3, the acid addition time is 20 min, and the acid mixing time is 10 min, thereby obtaining the positive electrode lead paste.

[0056] S2. Prepare the positive electrode plate, which includes the positive electrode lead paste and the positive electrode grid.

[0057] The steps for preparing the positive electrode plate are as follows: Step 2-1. Prepare an aqueous solution of carbon black, with the following weight components: 1 part of carbon black, 10 parts of deionized water, and 0.2 part of thickening agent sodium carboxymethyl cellulose; Step 2-2. Uniformly apply the positive electrode lead paste prepared in S1 onto the positive electrode alloy grid; Step 2-3. Spray the aqueous solution of carbon black on the surface of the lead paste, and after acid drenching and surface drying, conduct a curing treatment to obtain the positive electrode plate. The dosage of the aqueous solution of carbon black is 20 mg per gram of lead paste for spraying on both sides. The density of acid drenching is 1.15 g / cm3, and the surface drying temperature is 140 °C.

[0058] Specifically, the curing and drying treatment process is as follows: Step 1. The relative humidity is 95 - 100%, the temperature is 65 °C, and the controlled duration is 5 h; Step 2. The relative humidity is 85 - 90%, the temperature is 70 °C, and the controlled duration is 6 h; Step 3. The relative humidity is 85 - 90%, the temperature is 50 °C, and the controlled duration is 18 h; Step 4. The relative humidity is 5 - 20%, the temperature is 75 °C, and the controlled duration is 32 h.

[0059] Furthermore, the negative electrode lead paste includes the following materials in parts by weight: 100 parts of lead oxide powder, 12 parts of sulfuric acid, 20 parts of deionized water; 0.07 part of short fiber, 0.9 part of humic acid, 0.3 part of sodium lignosulfonate, 1 part of silicon dioxide, 1.6 parts of barium sulfate, 0.5 part of sodium sulfate, 0.1 part of ammonium persulfate, 0.1 part of vanillin, 0.4 part of tannin extract, and 0.4 part of mixed carbon material.

[0060] Specifically, the oxidation degree of the lead powder is 72%, the particle size is 3 - 4 μm, the silicon dioxide particles are ≤ 30 μm, and the carbon material is 0.2 part of acetylene black, 0.15 part of carbon black, and 0.05 part of graphene.

[0061] Furthermore, the preparation method of the negative electrode lead paste comprises the following steps: S1. According to the proportion, 0.9 parts of humic acid and 0.3 parts of sodium lignin sulfonate were added to 3 parts of deionized water and stirred to dissolve for 15 minutes. After adding 1 part of silicon dioxide particles to the prepared solution, the pressure was reduced to -0.15MPa for 20 minutes, and then the pressure was increased to 0.1MPa. After being fully mixed, the mixture was dried at 70°C for 40 hours to obtain a mixture B. S2, adding mixture B and 1.6 parts of barium sulfate and 0.5 parts of sodium sulfate in proportion into a ball mill for mixing and grinding to obtain mixture C, the ball mill speed is 250 rpm, and the premixing time is 0.5 h; S3, adding 0.4 parts of glue into 1.6 parts of deionized water to dissolve, to prepare glue solution; S4. Add mixture C, 0.07 parts of short fibers, 0.1 parts of ammonium persulfate, 0.1 parts of vanillin, 0.2 parts of acetylene black, 0.15 parts of carbon black and 0.05 parts of graphene into a paste mixer and dry mix with lead powder for 10 minutes. Then add 2 parts of glue solution and the remaining 15.4 parts of deionized water and 12 parts of sulfuric acid respectively for water mixing and acid mixing. The water adding time is 1 minute and the water mixing time is 5 minutes. The density of sulfuric acid is 1.4 g / cm3. The acid adding time is 15 minutes and the acid mixing time is 5 minutes, thereby preparing a negative electrode lead paste.

[0062] Furthermore, the electrolyte includes 0.6 parts of silicon dioxide, 50 parts of 98% anhydrous concentrated sulfuric acid, 4 parts of sodium compound, 0.15 parts of stannous sulfate, 0.7 parts of phosphoric acid, 2 parts of vanillin, and 100 parts of deionized water.

[0063] The sodium compound is 0.1 part of sodium stannate citrate, 0.1 part of sodium stannate, 2 parts of sodium tetraborate, 1.5 parts of sodium sulfate, 0.1 part of sodium silicate, 0.1 part of sodium polyaspartate, and 0.1 part of disodium nitrilotriacetate.

[0064] Furthermore, the specific preparation steps of the electrolyte are as follows: S1. Add 54 parts of deionized water to the acid preparation tank, and slowly add 50 parts of 98% concentrated sulfuric acid under constant stirring. After the addition is completed, wait until the solution temperature drops to room temperature; S2, according to the proportion, 4 parts of sodium compound, 0.15 parts of stannous sulfate, 0.7 parts of phosphoric acid, and 2 parts of vanillin were mixed and modified at a speed of 300 rpm for 0.5 h to obtain a mixture D; S3, the mixture D is added to 40 parts of deionized water, heated and stirred, and the heating is stopped after the temperature reaches 52°C, and the mixture is stirred evenly and then cooled to room temperature to obtain a mixed solution E; S4. Add 6 parts of deionized water to the colloid disperser, then add 0.6 part of fumed silica, and disperse at high speed for 3 h to form a uniform colloidal solution F. S5. Slowly add the mixture E and the colloidal solution F to the sulfuric acid solution prepared in S1 and stir. The stirring speed is 2500 rpm and the time is 20 min to obtain the electrolyte.

[0065] Comparative example A lead-acid battery includes a positive plate, a negative plate, and an electrolyte; the positive plate includes a positive lead paste and a positive plate grid, and the negative plate includes a negative lead paste and a negative plate grid.

[0066] Furthermore, the positive lead paste includes 100 parts of lead oxide powder, 8 parts of sulfuric acid, 12 parts of deionized water, 0.06 part of short fiber, 0.1 part of stannous sulfate, 0.1 part of antimony trioxide, and 0.3 part of graphite. The oxidation degree of the lead powder is 76%, and the particle size is 3 - 4 μm.

[0067] The steps for preparing the positive lead paste are as follows: According to the proportion, add 0.06 part of short fiber, 0.1 part of stannous sulfate, 0.1 part of antimony trioxide, and 0.3 part of graphite to the paste mixer and dry-mix with the lead powder for 7.5 min; in the paste mixer, perform water mixing and acid mixing with deionized water and sulfuric acid respectively. The water addition time is 2 min, the water mixing time is 7.5 min, the density of sulfuric acid is 1.4 g / cm3, the acid addition time is 17.5 min, and the acid mixing time is 7.5 min.

[0068] The steps for preparing the positive plate are as follows: The prepared positive lead paste is evenly coated on the positive alloy plate grid, and after acid spraying and surface drying, it is subjected to a curing treatment to obtain the positive plate. The density of the acid spraying is 1.15 g / cm3, and the surface drying temperature is 130 °C.

[0069] The curing and drying treatment process is as follows: Step 1, the relative humidity is 95 - 100%, the temperature is 70 °C, and the controlled duration is 4 h; Step 2, the relative humidity is 85 - 90%, the temperature is 50 °C, and the controlled duration is 30 h; Step 3, the relative humidity is 5 - 20%, the temperature is 75 °C, and the controlled duration is 30 h.

[0070] Furthermore, the negative lead paste includes the following materials in parts by weight: 100 parts of lead oxide powder, 9 parts of sulfuric acid, 12 parts of deionized water; 0.06 part of short fiber, 0.6 part of humic acid, 0.2 part of sodium lignosulfonate, 1.2 part of barium sulfate, 0.2 part of acetylene black, and 0.1 part of carbon black.

[0071] Further, for the preparation method of the negative electrode paste, 0.06 parts of short fibers, 0.6 parts of humic acid, 0.2 parts of sodium lignosulfonate, 1.1 parts of barium sulfate, 0.2 parts of acetylene black, and 0.1 part of carbon black are added to a paste mixer and dry-mixed with lead powder for 6 minutes. Then, they are mixed with 12 parts of deionized water and 9 parts of sulfuric acid respectively for water mixing and acid mixing. The water addition time is 1 minute, the water mixing time is 6 minutes, the density of sulfuric acid is 1.4 g / cm3, the acid addition time is 16 minutes, and the acid mixing time is 6 minutes, thereby obtaining the negative electrode paste.

[0072] Further, the electrolyte includes 40 parts of 98% anhydrous concentrated sulfuric acid, 0.1 part of stannous sulfate, 0.6 part of phosphoric acid, 80 parts of deionized water, 1.5 parts of sodium tetraborate, and 1 part of sodium sulfate.

[0073] Further, the specific preparation steps of the electrolyte are as follows: S1. Add 80 parts of deionized water to a acid mixing tank. Under continuous stirring, slowly add 40 parts of 98% concentrated sulfuric acid. After the addition is complete, wait for the solution temperature to drop to room temperature. S2. Slowly add 0.1 part of stannous sulfate, 0.6 part of phosphoric acid, 1.5 parts of sodium tetraborate, and 1 part of sodium sulfate to the sulfuric acid solution prepared in S1, and stir to obtain the electrolyte.

[0074] For the storage batteries made from the above electrolyte Examples 1, 2, 3, and the comparative example, the following test methods are used for testing: 10-hour rate capacity test: For a fully charged storage battery, within 1 h to 24 h after the end of charging, discharge it with a current of I 10 (A). The temperature around the storage battery should be maintained between 20~25°C. During the discharge time, the change in the current value should not be greater than 1%. When the voltage of a single battery of the storage battery reaches 1.80 V, stop discharging and record the discharge time, and calculate the discharge capacity.

[0075] -40°C low-temperature capacity test: Place a fully charged storage battery in an environment of -40°C ± 2°C and let it stand for 20 h. Discharge the storage battery with a current of I 10 (A). During the discharge process, the temperature around the storage battery should be maintained between -40°C ± 2°C, and the change in the current value should not be greater than 1%. When the voltage of a single battery of the storage battery reaches 1.80 V, stop discharging and record the discharge time, and calculate the discharge capacity.

[0076] Cycle life test: The temperature around the storage battery is maintained between 20~25°C. a) Discharge with a current of I 10 (A) until the voltage of a single battery of the storage battery reaches 1.80 V; b) Limit the voltage to 2.35 V / single battery and charge with 2.5I10 (A) for 12 h; c) Repeat steps a) and b). (When the discharge time in step a is less than 8 hours, the life test terminates) As can be seen from the above, as Figures 1-3 shown, when the solutions of Examples 1 to 3 are compared with the comparative example, with the 10-hour rate capacity being close, the lead dioxide content in the positive plate does not cause poor formation due to the addition of calcium sulfate, achieving the same effect as the comparative example. At the same time, it can be concluded that its low-temperature performance and cycle life are better. By using the paste and manufacturing method of the present invention, better low-temperature performance and cycle life can be obtained. The components of the present invention are simple, the production cost is relatively low, the manufactured storage battery has good low-temperature resistance performance and cycle life, and has a wide range of applications.

[0077] The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and modifications can also be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A lead-sodium battery, comprising a positive plate, a negative plate and an electrolyte, characterized in that: The positive plate comprises a positive lead paste and a positive grid, wherein the positive lead paste comprises the following components by weight: 100 parts of lead oxide powder, 6-10 parts of sulfuric acid, 14-24 parts of deionized water, 0.05-0.07 parts of short fibers, 2-8 parts of lead dioxide, 1-2 parts of tetrabasic lead sulfate, 0.5-1.5 parts of calcium sulfate, 0.05-0.15 parts of stannous sulfate, 0.05-0.15 parts of antimony trioxide, 0.5-1 parts of carbon black, 0.1-0.2 parts of sodium hydroxymethyl cellulose, and 0.1-0.5 parts of mixed carbon materials; The negative electrode plate includes a negative electrode lead paste and a negative electrode grid, and the negative electrode lead paste includes the following components by weight: 100 parts of lead oxide powder, 6-12 parts of sulfuric acid, 11-20 parts of deionized water; 0.05-0.07 parts of short fibers, 0.3-0.9 parts of humic acid, 0.1-0.3 parts of sodium lignin sulfonate, 0.06-1 parts of silicon dioxide, 0.8-1.6 parts of barium sulfate, 0.1-0.5 parts of sodium sulfate, 0.04-0.1 parts of ammonium persulfate, 0.06-0.1 parts of vanillin, 0.2-0.4 parts of glue, and 0.2-0.4 parts of mixed carbon material The electrolyte comprises the following materials in parts by weight: 0.2 to 0.6 parts of silicon dioxide, 30 to 50 parts of 98% anhydrous concentrated sulfuric acid, 2 to 4 parts of sodium compounds, 0.05 to 0.15 parts of stannous sulfate, 0.5 to 0.7 parts of phosphoric acid, 1 to 2 parts of vanillin, and 60 to 100 parts of deionized water.

2. A lead-sodium battery according to claim 1, characterized in that: The lead powder has an oxidation degree of 72-80%, a particle size of ≤5 μm, and a particle size of ≤30 μm; the mixed carbon material includes graphite, acetylene black, and graphene; the sodium compound is one or more of sodium stannate citrate, sodium stannate, sodium tetraborate, sodium sulfate, sodium silicate, sodium sulfide, sodium polyacrylate, sodium tripolyphosphate, sodium dimercaptosuccinate, sodium dodecylbenzene sulfonate, sodium polyfluoroalkyl sulfonate, sodium polyaspartate, and disodium nitrilotriacetate.

3. A lead-sodium battery according to claim 1 or 2, characterized in that: The preparation method of the positive electrode lead paste comprises the following steps: S1. Premix calcium sulfate, stannous sulfate and antimony trioxide according to a certain ratio to obtain a mixture A. S2. Add lead dioxide and tetrabasic lead sulfate into a paste mixer and dry mix with lead oxide powder according to the proportion; S3, adding mixture A, short fibers and mixed carbon materials in proportion to a paste mixer and dry mixing with the product of step 2; S4. Add deionized water and sulfuric acid into a paste mixing machine, mix them with water and acid, respectively, to prepare positive electrode lead paste.

4. A lead-sodium battery according to claim 3, characterized in that: In S1, a ball mill is used for premixing, the speed of the ball mill is 200-300 rpm, and the premixing time is 0.5-1h; in S2, the dry mixing time is 1-5min, and the dry mixing time in step 3 is 5-10min; in S4, water mixing and acid mixing are performed with deionized water and sulfuric acid in a paste mixer, respectively, the water adding time is 1-3min, and the water mixing time is 5-10min. The density of the sulfuric acid is 1.4g / cm 3 , acid adding time is 15~20min, and acid mixing time is 5~10min.

5. A lead-sodium battery according to claim 1 or 2, characterized in that: The method for preparing the positive electrode plate comprises the following steps: S1. Prepare a carbon black aqueous solution according to the following weight components: 0.5-1 part of carbon black, 5-10 parts of deionized water, and 0.1-0.2 parts of sodium hydroxymethyl cellulose; S2. Apply the positive electrode lead paste evenly to the positive electrode alloy grid; S3. Spray a carbon black aqueous solution on the surface of the lead paste, and then perform a curing treatment after acid rinsing and surface drying to obtain a positive electrode plate.

6. A lead-sodium battery according to claim 5, characterized in that: The sodium hydroxymethyl cellulose is a thickener, and the amount of the carbon black aqueous solution is 10-30 mg per gram of lead paste for spraying on both sides, and the acid spraying density is 1.15 g / cm 3 , the surface drying temperature is 120~140℃; the curing and drying process is as follows: Step a, relative humidity is 95-100%, temperature is 65-70°C, and control time is 4-5h; Step b, relative humidity is 85-90%, temperature is 70-76°C, and control time is 6-8h; Step c, relative humidity is 85-90%, temperature is 50-55°C, and control time is 16-18h; Step d: relative humidity is 5-20%, temperature is 75-80°C, and control time is 30-32 hours.

7. A lead-sodium battery according to claim 1 or 2, characterized in that: The preparation method of the negative electrode lead paste comprises the following steps: S1. Add humic acid and sodium lignin sulfonate to deionized water according to the proportion, stir and dissolve, add silicon dioxide particles in a set proportion to the prepared solution, reduce pressure and increase pressure, mix thoroughly and dry to obtain a mixture B; S2, adding mixture B and barium sulfate and sodium sulfate in proportion into a ball mill and mixing them to obtain mixture C; S3, adding the adhesive to deionized water to dissolve according to the proportion to prepare an adhesive solution; S4. Add the mixture C, short fibers, ammonium persulfate, vanillin, and mixed carbon materials into a paste mixer and dry mix with lead powder. Then, add the glue solution and the remaining deionized water and sulfuric acid respectively for water mixing and acid mixing to prepare a negative electrode lead paste.

8. A lead-sodium battery according to claim 7, characterized in that: The stirring time of the stirring and dissolving in S1 is greater than 10 minutes. After adding the set proportion of silicon dioxide particles to the prepared solution, the pressure is reduced to -0.1~-0.3MPa, and then the pressure is increased to 0.1MPa. After sufficient mixing, the solution is dried at a drying temperature of ≥60°C and the time is greater than 5 hours. The ball mill speed in S2 is 200~300rpm, and the mixing time is 0.5~1h. The dry mixing time in S4 is 5~12 minutes, and the glue solution and the remaining deionized water and sulfuric acid are mixed with water and acid respectively. The water adding time is 1~3 minutes, and the water mixing time is 5~10 minutes. The density of the sulfuric acid is 1.4g / cm 3 , acid adding time is 15~20min, and acid mixing time is 5~10min.

9. A lead-sodium battery according to claim 1 or 2, characterized in that: The preparation method of the electrolyte comprises the following steps: S1. Add deionized water in proportion to the acid preparation tank, and slowly add 98% anhydrous concentrated sulfuric acid under constant stirring. After the addition is completed, wait for the solution temperature to drop to room temperature; S2. Mix and modify the sodium compound, stannous sulfate, phosphoric acid and vanillin according to the proportion to obtain a mixture D; S3, adding mixture D into deionized water, heating and stirring, heating to the set temperature, stopping heating, continuing to stir evenly, and waiting for the solution to cool to room temperature, to obtain a mixed solution E; S4, adding deionized water to the colloidal disperser, and then adding fumed silica, and dispersing at high speed to form a uniform colloidal solution F; S5. Slowly add the mixed solution E and the colloidal solution F in proportion to the sulfuric acid solution prepared in S1 and stir to obtain an electrolyte.

10. A lead-sodium battery according to claim 9, characterized in that: The grinding and modification speed in S2 is not less than 200 rpm, and the time is not less than 0.5 h; the temperature in S3 is raised to 48~52°C; the high-speed dispersion in S4 is 1~3 h; the stirring speed in S5 is not less than 1500 rpm, and the time is not less than 20 min.

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