A lead-sodium battery

Abstract

The invention discloses a lead-sodium battery in the field of battery technology, comprising a positive plate, a negative plate, and an electrolyte: the positive plate comprises a positive lead paste and a positive grid, the positive lead paste comprises 100 parts of lead oxide powder, 6 to 12 parts of sulfuric acid, 5 to 15 parts of deionized water, 0.05 to 0.1 parts of short fibers or conductive graphite fibers, and 0.4 to 2 parts of a mixture; the negative plate comprises a negative lead paste and a negative grid, the negative lead paste comprises 100 parts of lead oxide powder, 6 to 12 parts of sulfuric acid, 5 to 15 parts of deionized water, 0.05 to 0.1 parts of short fibers or conductive graphite fibers, and 0.4 to 2 parts of a mixture. The invention discloses a lead-acid battery comprising: a first electrolyte solution comprising 0.01 to 0.6 parts of silicon dioxide, 30 to 50 parts of 98% anhydrous concentrated sulfuric acid, 2 to 7 parts of a sodium compound, 0.1 to 0.15 parts of stannous sulfate, 0.5 to 0.8 parts of phosphoric acid, 1 to 2 parts of vanillin, and 40 to 60 parts of deionized water. The lead-acid battery can effectively achieve good low-temperature resistance and extend the service life of the battery.

Description

Technical Field

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

[0002] Lead-acid batteries have a history of over 160 years, and their production process is relatively mature. However, drawbacks such as poor low-temperature performance and a short lifespan limit their application in some scenarios. National and industry standards for lead-acid batteries specify a minimum operating temperature of -30°C. In actual use, temperatures can drop below -40°C. Furthermore, the battery's charge acceptance deteriorates in low temperatures, shortening its cycle life. Therefore, a lead-sodium battery is needed to address these issues. 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 the lead-acid battery and extend the service life of the battery.

[0004] The object of the present invention is achieved as follows: A lead-sodium battery comprises a positive plate, a negative plate and an electrolyte.

[0005] The positive plate includes a positive lead paste and a positive grid, wherein the positive lead paste includes 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;

[0006] The negative electrode plate includes a negative electrode lead paste and a negative electrode grid. 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.

[0007] The electrolyte includes 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 compound, 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.

[0008] Furthermore, 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; and the sodium compound is one or more of sodium citrate stannate, sodium stannate, sodium tetraborate, sodium sulfate, sodium silicate, sodium sulfide, sodium polyacrylate, sodium tripolyphosphate, sodium dimercaptosuccinate, sodium dodecylbenzenesulfonate, sodium polyfluoroalkylsulfonate, sodium polyaspartate, and disodium nitrilotriacetate.

[0009] Furthermore, the preparation method of the positive electrode lead paste comprises the following steps:

[0010] S1. Premix calcium sulfate, stannous sulfate, and antimony trioxide according to a certain ratio to obtain a mixture A.

[0011] S2. Add lead dioxide and tetrabasic lead sulfate into a paste mixer and dry mix with lead oxide powder according to the proportion;

[0012] 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;

[0013] S4. Deionized water and sulfuric acid are added into a paste mixing machine, and the mixture is mixed with water and acid respectively, thereby preparing a positive electrode lead paste.

[0014] Furthermore, a ball mill is used for premixing in S1, the ball mill speed is 200-300 rpm, and the premixing time is 0.5-1h; the dry mixing time in S2 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 addition 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.

[0015] Furthermore, the preparation method of the positive electrode plate includes the following steps:

[0016] S1. Prepare a carbon black aqueous solution according to the following weight components: 0.5-1 part carbon black, 5-10 parts deionized water, and 0.1-0.2 parts sodium hydroxymethyl cellulose;

[0017] S2. Apply the positive electrode lead paste evenly to the positive electrode alloy grid;

[0018] S3. Spraying carbon black aqueous solution on the surface of the lead paste, rinsing with acid, drying the surface and then performing curing treatment to obtain a positive electrode plate.

[0019] Furthermore, the sodium hydroxymethyl cellulose is a thickener, the amount of the carbon black aqueous solution is 10-30 mg per gram of lead paste for double-sided spraying, and the acid density is 1.15 g / cm 3, the surface drying temperature is 120~140℃; the curing and drying process is as follows:

[0020] Step a: relative humidity is 95-100%, temperature is 65-70°C, and control time is 4-5 hours;

[0021] Step b: relative humidity is 85-90%, temperature is 70-76°C, and control time is 6-8 hours;

[0022] Step c: relative humidity is 85-90%, temperature is 50-55°C, and control time is 16-18 hours;

[0023] Step d: The relative humidity is 5-20%, the temperature is 75-80°C, and the control time is 30-32 hours.

[0024] Furthermore, the preparation method of the negative electrode lead paste comprises the following steps:

[0025] 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, then reduce and increase the pressure, mix thoroughly, and dry to obtain a mixture B;

[0026] S2. Add mixture B, barium sulfate and sodium sulfate in proportion to each other in a ball mill and mix them to obtain mixture C;

[0027] S3. Add the adhesive to deionized water and dissolve it in a certain proportion to prepare an adhesive solution;

[0028] S4. Add 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.

[0029] Furthermore, the stirring time of the stirring and dissolving in S1 is greater than 10 minutes. After adding the set proportion of silica particles to the prepared solution, the pressure is reduced to -0.1~-0.3MPa, and then increased to 0.1MPa. After thorough mixing, the drying process is performed at a drying temperature of ≥60°C and a time of 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 adhesive solution and the remaining deionized water and sulfuric acid are mixed with water and acid respectively. The water addition 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.

[0030] Furthermore, the preparation method of the electrolyte comprises the following steps:

[0031] S1. Add deionized water in proportion to the acid preparation tank. 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.

[0032] S2. Mix and modify the sodium compound, stannous sulfate, phosphoric acid, and vanillin according to a certain proportion to obtain a mixture D.

[0033] S3. Add mixture D to deionized water, heat and stir. After the temperature reaches the set temperature, stop heating, continue stirring until the solution is evenly cooled to room temperature, and obtain mixed solution E.

[0034] S4, add deionized water to the colloidal disperser, then add fumed silica, and disperse at high speed to form a uniform colloidal solution F;

[0035] 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 prepare an electrolyte.

[0036] Furthermore, 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 is raised to 48~52°C in S3; the high-speed dispersion is carried out for 1~3 h in S4; and the stirring speed in S5 is not less than 1500 rpm, and the time is not less than 20 min.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] In the positive lead paste of the present invention, calcium sulfate, stannous sulfate, and antimony trioxide are premixed to obtain a mixture A, achieving physical intercalation. The powder particles are uniform in size, ensuring that the ground mixture and paste can be evenly distributed in the active material. At the same time, the calcium sulfate particles become smaller, reducing their impact on the formation efficiency, thereby exerting their effect on the low-temperature performance of the battery. Lead dioxide replaces red lead, solving the problem of red lead purity on 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 plate, which can effectively increase the initial conductivity of the plate, making the high-current discharge performance at low temperatures more obvious.

[0039] The negative electrode lead paste of the present invention effectively improves the stability of additives and the uniformity of mixing. Mixture B has a more stable structure. Humic acid and sodium lignin sulfonate are immersed in silicon dioxide particles by increasing and decreasing the pressure, thereby solving the instability problem of sodium lignin sulfonate. During battery charging and discharging, the sodium lignin sulfonate in mixture B is not easily dissolved. At the same time, under the action of humic acid and silicon dioxide, 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 higher conductive network, improve the conductivity and the activity of ion migration under low temperature conditions. Mixture B is further added to a ball mill and mixed with barium sulfate and sodium sulfate to obtain mixture C, achieving physical intercalation. The powder particles are uniform in size, ensuring that the ground mixture and paste can be evenly distributed in the active material, so that the performance of each mixed component material in the battery is fully exerted. Under the joint action of other additives such as ammonium persulfate, vanillin, and glue, the stability, low-temperature resistance and service life of the battery are improved.

[0040] The electrolyte of the present invention reduces electrolyte viscosity and enhances ion migration efficiency by adding sodium to the mixture, thereby reducing internal resistance growth in low-temperature environments and improving the battery's discharge capacity and charge acceptance at low temperatures. A sodium compound, stannous sulfate, phosphoric acid, and vanillin are mixed and modified to produce mixture D, a composite additive with a smaller particle structure. This mixture is then heated and stirred in deionized water until the temperature reaches a set temperature, then stopped heating, stirred evenly, and cooled to room temperature to produce mixed solution E. The substances in mixed solution E are more dispersed, improving uniformity after the addition of sulfuric acid. Colloidal solution F, with a lower freezing point than sulfuric acid electrolyte, can improve low-temperature performance to a certain extent. It also effectively prevents electrolyte stratification, ensuring uniform density between the upper and lower electrolyte layers of the battery, and avoiding the lifespan shortening problem of conventional lead-acid batteries caused by concentration differences. The synergistic effect of mixture E and colloidal solution F further enhances low-temperature cycling stability. Furthermore, the improved electrolyte performance achieved by the addition of the sodium compound can enhance internal charge balance efficiency and optimize ion transport pathways, thereby stabilizing voltage and increasing overall capacity.

[0041] In summary, the present invention is beneficial to maintaining the cycle capacity of the battery and the low-temperature performance of the battery through the design improvement of the process, thereby effectively achieving the advantages of good low-temperature resistance of the battery and extending the service life of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0043] Figure 1 Schematic diagram of discharge under low temperature conditions for the embodiment of the present invention and the comparative example.

[0044] Figure 2 Schematic diagram of discharge at room temperature for the embodiment of the present invention and the comparative example.

[0045] Figure 3 Graph showing the cycle life of the embodiment of the present invention and the comparative example. DETAILED DESCRIPTION

[0046] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0047] Example 1

[0048] A lead-sodium battery comprises a positive plate, a negative plate and an electrolyte; the positive plate comprises a positive lead paste and a positive grid, and the negative plate comprises a negative lead paste and a negative grid.

[0049] Furthermore, the preparation method of the positive electrode plate includes:

[0050] S1. Prepare positive electrode lead paste.

[0051] The positive electrode lead paste includes 100 parts of lead oxide powder, 6 parts of sulfuric acid, 14 parts of deionized water, 0.05 parts of short fibers, 2 parts of lead dioxide, 1 part of tetrabasic lead sulfate, 0.5 parts of calcium sulfate, 0.05 parts of stannous sulfate, 0.05 parts of antimony trioxide, 0.5 parts of carbon black, 0.1 parts of sodium hydroxymethyl cellulose, and 0.1 parts of mixed carbon materials.

[0052] Specifically, the lead oxide powder has an oxidation degree of 72%, a particle size of 2-3 μm, and the mixed carbon material comprises 0.05% graphite, 0.025% acetylene black, and 0.025% graphene.

[0053] The specific steps are as follows:

[0054] S1-1. Premix 0.5 parts of calcium sulfate, 0.05 parts of stannous sulfate, and 0.05 parts of antimony trioxide in the above proportions using a ball mill at a speed of 200 rpm for 1 hour.

[0055] S1-2. Add 2 parts of lead dioxide and 1 part of tetrabasic lead sulfate to a paste mixer and dry mix with lead oxide powder for 1 minute.

[0056] S1-3. Add the product of S1-1, 0.05 parts of short fibers, and 0.1 parts of mixed carbon materials into a paste mixer and dry mix with lead powder for 5 minutes;

[0057] S1-4. Mix the lead paste with deionized water and sulfuric acid in a paste mixing machine, respectively. The water adding time is 1 minute, 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 obtaining a positive electrode lead paste.

[0058] S2 prepares a positive electrode plate, which includes a positive electrode lead paste and a positive electrode grid.

[0059] Furthermore, the steps for preparing the positive plate are as follows:

[0060] Step 2-1, prepare a carbon black aqueous solution according to the following weight components: 0.5 parts of carbon black, 5 parts of deionized water, and 0.1 parts of sodium hydroxymethyl cellulose as a thickener;

[0061] Step 2-2: The positive electrode lead paste prepared in step S1 is evenly applied to the positive electrode alloy grid;

[0062] Step 2-3: spray a carbon black aqueous solution on the surface of the lead paste, and then cure it after acid spraying and surface drying to obtain a positive plate. The amount of carbon black aqueous solution is 10 mg per gram of lead paste and sprayed on both sides. The acid spraying density is 1.15 g / cm3, and the surface drying temperature is 120°C.

[0063] Specifically, the curing and drying process is as follows:

[0064] Step 1: Relative humidity is 95-100%, temperature is 70°C, and control time is 4 hours;

[0065] Step 2: The relative humidity is 85-90%, the temperature is 76°C, and the control time is 8 hours;

[0066] Step 3: The relative humidity is 85-90%, the temperature is 55°C, and the control time is 18 hours;

[0067] Step 4: The relative humidity is 5-20%, the temperature is 80°C, and the control time is 30 hours.

[0068] 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 parts of short fibers, 0.3 parts of humic acid, 0.1 parts of sodium lignin sulfonate, 0.06 parts of silicon dioxide, 0.8 parts of barium sulfate, 0.1 parts of sodium sulfate, 0.04 parts of ammonium persulfate, 0.06 parts of vanillin, 0.2 parts of glue, and 0.2 parts of mixed carbon material.

[0069] Specifically, the lead powder has an oxidation degree of 72%, a particle size of 3-4 μm, silicon dioxide particles ≤ 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.

[0070] Furthermore, the preparation method of the negative electrode lead paste comprises the following steps:

[0071] S1. According to the proportion, 0.3 parts of humic acid and 0.1 parts of sodium lignin sulfonate were added to 1 part of deionized water and stirred for 20 minutes. 0.06 parts of silicon dioxide particles were added to the prepared solution, and the pressure was reduced to -0.1 MPa for 30 minutes, and then increased to 0.1 MPa. After thorough mixing, the mixture was dried at 90°C for 24 hours to obtain a mixture B.

[0072] S2. Add mixture B, 0.8 parts of barium sulfate and 0.1 parts of sodium sulfate in proportion to each other into a ball mill and mix them to obtain mixture C. The ball mill speed is 300 rpm and the premixing time is 0.5 h.

[0073] S3, dissolving 0.2 parts of adhesive in 0.8 parts of deionized water to prepare an adhesive solution;

[0074] S4. Add mixture C, 0.05 parts of short fibers, 0.04 parts of ammonium persulfate, 0.06 parts of vanillin, 0.1 parts of acetylene black, 0.05 parts of carbon black, and 0.05 parts of graphene into a paste mixer and dry mix with lead powder for 8 minutes. Then add 1 part of the glue solution and the remaining 9 parts of deionized water and 6 parts of sulfuric acid respectively for water mixing and acid mixing. The water adding time is 1.5 minutes, the water mixing time is 6 minutes, the density of sulfuric acid is 1.4 g / cm3, the acid adding time is 17 minutes, and the acid mixing time is 5 minutes, thereby preparing the negative electrode lead paste.

[0075] Furthermore, the electrolyte includes 0.2 parts of silicon dioxide, 30 parts of 98% anhydrous concentrated sulfuric acid, 2 parts of sodium compound, 0.05 parts of stannous sulfate, 0.5 parts of phosphoric acid, 1 part of vanillin, and 60 parts of deionized water.

[0076] Specifically, the sodium compound is 0.05 parts of sodium stannate citrate, 1 part of sodium tetraborate, 0.5 parts of sodium sulfate, 0.1 parts of sodium polyacrylate, 0.1 parts of sodium tripolyphosphate, 0.1 parts of sodium dodecylbenzenesulfonate, 0.1 parts of sodium polyaspartate, and 0.05 parts of disodium nitrilotriacetate.

[0077] Furthermore, the specific preparation steps of the electrolyte are as follows:

[0078] S1. Add 38 parts of deionized water to the acid preparation tank. Slowly add 30 parts of 98% concentrated sulfuric acid under constant stirring. After the addition is completed, wait until the solution temperature drops to room temperature.

[0079] S2. Mix and modify 2 parts of a sodium compound, 0.05 parts of stannous sulfate, 0.5 parts of phosphoric acid, and 1 part of vanillin according to the proportions at a speed of 200 rpm for 1.5 hours to obtain a mixture D.

[0080] S3. Add mixture D to 20 parts of deionized water, heat and stir until the temperature reaches 48°C, stop heating, continue stirring until the solution is cooled to room temperature, and obtain mixed solution E.

[0081] S4. Add 2 parts of deionized water to the colloidal disperser, then add 0.2 parts of fumed silica, and perform high-speed dispersion for 1 hour to form a uniform colloidal solution F;

[0082] S5. Slowly add the mixed solution E and the colloidal solution F to the sulfuric acid solution prepared in S1 and stir at a stirring speed of 1500 rpm for 30 minutes to prepare an electrolyte.

[0083] Example 2

[0084] A lead-sodium battery comprises a positive plate, a negative plate and an electrolyte; the positive plate comprises a positive lead paste and a positive grid, and the negative plate comprises a negative lead paste and a negative grid.

[0085] Furthermore, the preparation method of the positive electrode plate includes:

[0086] S1. Prepare positive electrode lead paste.

[0087] The positive electrode lead paste includes 100 parts of lead oxide powder, 8 parts of sulfuric acid, 19 parts of deionized water, 0.06 parts of short fibers, 5 parts of lead dioxide, 1.5 parts of tetrabasic lead sulfate, 1 part of calcium sulfate, 0.1 part of stannous sulfate, 0.1 part of antimony trioxide, 0.75 parts of carbon black, 0.15 parts of sodium hydroxymethyl cellulose, and 0.3 parts of mixed carbon materials.

[0088] Specifically, the lead oxide powder has an oxidation degree of 76%, a particle size of 3-4 μm, and the mixed carbon material is 0.2% graphite, 0.05% acetylene black, and 0.05% graphene.

[0089] The specific steps are as follows:

[0090] S1-1. Premix 1 part of calcium sulfate, 0.1 part of stannous sulfate, and 0.1 part of antimony trioxide in the above proportions using a ball mill at a speed of 250 rpm for 45 minutes.

[0091] S1-2. Add 5 parts of lead dioxide and 1.5 parts of tetrabasic lead sulfate to a paste mixer and dry mix with lead oxide powder for 3 minutes according to the above ratio.

[0092] S1-3. Add the product of S1-1, 0.06 parts of short fibers, and 0.3 parts of mixed carbon materials into a paste mixer and dry mix with lead powder for 7.5 minutes;

[0093] S1-4. Mix the lead paste with deionized water and sulfuric acid in a paste mixing machine, respectively. The water adding time is 2 minutes, the water mixing time is 7.5 minutes, the density of sulfuric acid is 1.4 g / cm3, the acid adding time is 17.5 minutes, and the acid mixing time is 7.5 minutes, thereby obtaining a positive electrode lead paste.

[0094] S2 prepares a positive electrode plate, which includes a positive electrode lead paste and a positive electrode grid.

[0095] Furthermore, the steps for preparing the positive plate are as follows:

[0096] Step 2-1, prepare a carbon black aqueous solution according to the following weight components: 0.75 parts of carbon black, 7.5 parts of deionized water, and 0.15 parts of sodium hydroxymethyl cellulose as a thickener;

[0097] Step 2-2: The positive electrode lead paste prepared in step S1 is evenly applied to the positive electrode alloy grid;

[0098] Step 2-3: spray a carbon black aqueous solution on the surface of the lead paste, and then cure it after acid spraying and surface drying to obtain a positive plate. The amount of carbon black aqueous solution is 20 mg per gram of lead paste and sprayed on both sides. The acid spraying density is 1.15 g / cm3, and the surface drying temperature is 130°C.

[0099] Specifically, the curing and drying process is as follows:

[0100] Step 1: Relative humidity is 95-100%, temperature is 67°C, and control time is 4.5 hours;

[0101] Step 2: The relative humidity is 85-90%, the temperature is 73°C, and the control time is 7 hours;

[0102] Step 3: The relative humidity is 85-90%, the temperature is 53°C, and the control time is 17 hours;

[0103] Step 4: The relative humidity is 5-20%, the temperature is 78°C, and the control time is 31 hours.

[0104] 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 parts of short fibers, 0.6 parts of humic acid, 0.2 parts of sodium lignin sulfonate, 0.08 parts of silicon dioxide, 1.2 parts of barium sulfate, 0.3 parts of sodium sulfate, 0.07 parts of ammonium persulfate, 0.08 parts of vanillin, 0.3 parts of glue, and 0.3 parts of mixed carbon material.

[0105] Specifically, the lead powder has an oxidation degree of 74%, a particle size of 4-5 μm, silicon dioxide particles ≤ 30 μm, and the carbon material is 0.2 parts of acetylene black, 0.05 parts of carbon black, and 0.05 parts of graphene.

[0106] Furthermore, the preparation method of the negative electrode lead paste comprises the following steps:

[0107] S1. According to the proportion, 0.6 parts of humic acid and 0.2 parts of sodium lignin sulfonate were added to 2 parts of deionized water and stirred for 20 minutes. 0.08 parts of silicon dioxide particles were added to the prepared solution, and the pressure was reduced to -0.1 MPa for 45 minutes, and then increased to 0.1 MPa. After thorough mixing, the mixture was dried at 75°C for 36 hours to obtain a mixture B.

[0108] S2. Add mixture B, 1.2 parts of barium sulfate and 0.3 parts of sodium sulfate in proportion to each other in a ball mill and grind them to obtain mixture C. The ball mill speed is 200 rpm and the premixing time is 1 hour.

[0109] S3, dissolving 0.3 parts of adhesive in 1.2 parts of deionized water to prepare an adhesive solution;

[0110] S4. Add mixture C, 0.06 parts of short fibers, 0.07 parts of ammonium persulfate, 0.08 parts of vanillin, 0.2 parts of acetylene black, 0.05 parts of carbon black, and 0.05 parts of graphene into a paste mixer and dry mix with lead powder for 6 minutes. Then, add 1.5 parts of the glue solution and 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 minute, the water mixing time is 6 minutes, the density of sulfuric acid is 1.4 g / cm3, the acid adding time is 16 minutes, and the acid mixing time is 6 minutes, thereby preparing a negative electrode lead paste.

[0111] Furthermore, the electrolyte includes 0.4 parts of silicon dioxide, 40 parts of 98% anhydrous concentrated sulfuric acid, 3 parts of sodium compound, 0.1 parts of stannous sulfate, 0.6 parts of phosphoric acid, 1.5 parts of vanillin, and 80 parts of deionized water.

[0112] Specifically, the sodium compound is 0.1 parts of sodium citrate stannate, 1.5 parts of sodium tetraborate, 1 part of sodium sulfate, 0.05 parts of sodium silicate, 0.15 parts of sodium polyacrylate, 0.15 parts of sodium polyaspartate, and 0.05 parts of disodium nitrilotriacetate.

[0113] Furthermore, the specific preparation steps of the electrolyte are as follows:

[0114] S1. Add 46 parts of deionized water to the acid preparation tank. Slowly add 40 parts of 98% concentrated sulfuric acid under constant stirring. After the addition is completed, wait until the solution temperature drops to room temperature.

[0115] S2. Mix 3 parts of a sodium compound, 0.1 parts of stannous sulfate, 0.6 parts of phosphoric acid, and 1.5 parts of vanillin according to the proportions, at a speed of 250 rpm for 1 hour to obtain a mixture D.

[0116] S3. Add mixture D to 30 parts of deionized water, heat and stir. After the temperature reaches 50°C, stop heating, continue stirring, and wait for the solution to cool to room temperature to obtain a mixed solution E.

[0117] S4. Add 4 parts of deionized water to the colloidal disperser, then add 0.4 parts of fumed silica, and perform high-speed dispersion for 2 hours to form a uniform colloidal solution F;

[0118] S5. Slowly add the mixed solution E and the colloidal solution F to the sulfuric acid solution prepared in S1 and stir at a stirring speed of 2000 rpm for 25 minutes to prepare an electrolyte.

[0119] Example 3

[0120] A lead-sodium battery comprises a positive plate, a negative plate and an electrolyte; the positive plate comprises a positive lead paste and a positive grid, and the negative plate comprises a negative lead paste and a negative grid.

[0121] Furthermore, the preparation method of the positive electrode plate includes:

[0122] S1. Prepare positive electrode lead paste.

[0123] The positive electrode lead paste includes 100 parts of lead oxide powder, 10 parts of sulfuric acid, 24 parts of deionized water, 0.07 parts of short fibers, 8 parts of lead dioxide, 2 parts of tetrabasic lead sulfate, 1.5 parts of calcium sulfate, 0.15 parts of stannous sulfate, 0.15 parts of antimony trioxide, 1 part of carbon black, 0.2 parts of sodium hydroxymethyl cellulose, and 0.5 parts of mixed carbon materials.

[0124] Specifically, the lead oxide powder has an oxidation degree of 80%, a particle size of 4-5 μm, and the mixed carbon material is 0.3% graphite, 0.1% acetylene black, and 0.1% graphene.

[0125] The steps for preparing positive lead paste are as follows:

[0126] S1-1, according to the above proportions, 1.5 parts of calcium sulfate, 0.15 parts of stannous sulfate, and 0.15 parts of antimony trioxide were premixed by ball mill at a speed of 300 rpm for 0.5 h;

[0127] S1-2. Add 8 parts of lead dioxide and 2 parts of tetrabasic lead sulfate into a paste mixer and dry mix with lead oxide powder for 5 minutes according to the above ratio.

[0128] S1-3. Add the product of S1-1, 0.07 parts of short fibers, and 0.5 parts of mixed carbon materials into a paste mixer and dry mix with lead powder for 10 minutes;

[0129] S1-4. Mix the lead paste with deionized water and sulfuric acid in a paste mixing machine, respectively. The water adding time is 3 minutes, the water mixing time is 10 minutes, the density of sulfuric acid is 1.4 g / cm3, the acid adding time is 20 minutes, and the acid mixing time is 10 minutes, thereby obtaining a positive electrode lead paste.

[0130] S2 prepares a positive electrode plate, which includes a positive electrode lead paste and a positive electrode grid.

[0131] The steps for preparing the positive plate are as follows:

[0132] Step 2-1, prepare a carbon black aqueous solution according to the following weight components: 1 part of carbon black, 10 parts of deionized water, and 0.2 parts of sodium hydroxymethyl cellulose as a thickener;

[0133] Step 2-2: The positive electrode lead paste prepared in step S1 is evenly applied to the positive electrode alloy grid;

[0134] Step 2-3: spray a carbon black aqueous solution on the surface of the lead paste, and then cure it after acid spraying and surface drying to obtain a positive plate. The amount of carbon black aqueous solution is 20 mg per gram of lead paste and sprayed on both sides. The acid spraying density is 1.15 g / cm3, and the surface drying temperature is 140°C.

[0135] Specifically, the curing and drying process is as follows:

[0136] Step 1: Relative humidity is 95-100%, temperature is 65°C, and control time is 5 hours;

[0137] Step 2: The relative humidity is 85-90%, the temperature is 70°C, and the control time is 6 hours;

[0138] Step 3: The relative humidity is 85-90%, the temperature is 50°C, and the control time is 18 hours;

[0139] Step 4: The relative humidity is 5-20%, the temperature is 75°C, and the control time is 32 hours.

[0140] 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 parts of short fibers, 0.9 parts of humic acid, 0.3 parts of sodium lignin sulfonate, 1 part of silicon dioxide, 1.6 parts of barium sulfate, 0.5 parts of sodium sulfate, 0.1 parts of ammonium persulfate, 0.1 parts of vanillin, 0.4 parts of glue, and 0.4 parts of mixed carbon material.

[0141] Specifically, the lead powder has an oxidation degree of 72%, a particle size of 3-4 μm, silicon dioxide particles ≤ 30 μm, and the carbon material is 0.2 parts of acetylene black, 0.15 parts of carbon black, and 0.05 parts of graphene.

[0142] Furthermore, the preparation method of the negative electrode lead paste comprises the following steps:

[0143] 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, stirred and dissolved for 15 minutes, 1 part of silicon dioxide particles was added to the prepared solution, and the pressure was reduced to -0.15 MPa for 20 minutes, and then increased to 0.1 MPa. After thorough mixing, the mixture was dried at 70°C for 40 hours to obtain a mixture B.

[0144] S2. Add mixture B, 1.6 parts of barium sulfate and 0.5 parts of sodium sulfate in proportion to each other in a ball mill and grind them to obtain mixture C. The ball mill speed is 250 rpm and the premixing time is 0.5 h.

[0145] S3, dissolving 0.4 parts of adhesive in 1.6 parts of deionized water to prepare an adhesive solution;

[0146] 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 the 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, 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.

[0147] 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.

[0148] The sodium compound is 0.1 part of sodium citrate stannate, 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.

[0149] Furthermore, the specific preparation steps of the electrolyte are as follows:

[0150] S1. Add 54 parts of deionized water to the acid preparation tank. 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.

[0151] S2. According to the proportion, 4 parts of the 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;

[0152] S3. Add mixture D to 40 parts of deionized water, heat and stir until the temperature reaches 52°C, stop heating, continue stirring until the solution is cooled to room temperature, and obtain mixed solution E;

[0153] S4. Add 6 parts of deionized water to the colloidal disperser, then add 0.6 parts of fumed silica, and disperse at high speed for 3 hours to form a uniform colloidal solution F;

[0154] S5. Slowly add the mixed solution E and the colloidal solution F to the sulfuric acid solution prepared in S1 and stir at a stirring speed of 2500 rpm for 20 minutes to prepare an electrolyte.

[0155] Comparative Example

[0156] A lead-acid battery comprises a positive plate, a negative plate and an electrolyte; the positive plate comprises a positive lead paste and a positive grid, and the negative plate comprises a negative lead paste and a negative grid.

[0157] Furthermore, the positive electrode lead paste includes 100 parts lead oxide powder, 8 parts sulfuric acid, 12 parts deionized water, 0.06 parts short fibers, 0.1 parts stannous sulfate, 0.1 parts antimony trioxide, and 0.3 parts graphite. The lead powder has an oxidation degree of 76% and a particle size of 3-4 μm.

[0158] The steps for preparing positive electrode lead paste are as follows: according to the proportion, 0.06 parts of short fibers, 0.1 parts of stannous sulfate, 0.1 parts of antimony trioxide, and 0.3 parts of graphite are added to a paste mixer and dry mixed with lead powder for 7.5 minutes; water-mixed and acid-mixed with deionized water and sulfuric acid are respectively carried out in the paste mixer, with the water adding time being 2 minutes and the water mixing time being 7.5 minutes. The density of sulfuric acid is 1.4 g / cm3, the acid adding time being 17.5 minutes, and the acid mixing time being 7.5 minutes.

[0159] The steps for preparing the positive plate are as follows: the prepared positive lead paste is evenly applied to the positive alloy grid, and then treated with acid leaching, surface drying, and then cured to produce the positive plate. The acid leaching density is 1.15g / cm3, and the surface drying temperature is 130°C.

[0160] The curing and drying process is as follows: Step 1, relative humidity is 95~100%, temperature is 70℃, and the control time is 4h; Step 2, relative humidity is 85~90%, temperature is 50℃, and the control time is 30h; Step 3, relative humidity is 5~20%, temperature is 75℃, and the control time is 30h.

[0161] 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, 12 parts of deionized water; 0.06 parts of short fibers, 0.6 parts of humic acid, 0.2 parts of sodium lignin sulfonate, 1.2 parts of barium sulfate, 0.2 parts of acetylene black, and 0.1 parts of carbon black.

[0162] Furthermore, a method for preparing a negative electrode lead paste is provided, wherein 0.06 parts of short fibers, 0.6 parts of humic acid, 0.2 parts of sodium lignin sulfonate, 1.1 parts of barium sulfate, 0.2 parts of acetylene black, and 0.1 parts of carbon black are added to a paste mixer and dry-mixed with lead powder for 6 minutes, and then mixed with 12 parts of deionized water and 9 parts of sulfuric acid for water and acid respectively, with the water adding time being 1 minute and the water mixing time being 6 minutes, the density of sulfuric acid being 1.4 g / cm3, the acid adding time being 16 minutes, and the acid mixing time being 6 minutes, thereby preparing a negative electrode lead paste.

[0163] Furthermore, the electrolyte includes 40 parts of 98% anhydrous concentrated sulfuric acid, 0.1 parts of stannous sulfate, 0.6 parts of phosphoric acid, 80 parts of deionized water, 1.5 parts of sodium tetraborate, and 1 part of sodium sulfate.

[0164] Furthermore, the specific preparation steps of the electrolyte are as follows:

[0165] S1. Add 80 parts of deionized water to the acid preparation tank. Slowly add 40 parts of 98% concentrated sulfuric acid under constant stirring. After the addition is completed, wait until the solution temperature drops to room temperature.

[0166] S2. Slowly add 0.1 parts of stannous sulfate, 0.6 parts 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 prepare an electrolyte.

[0167] The batteries prepared from the electrolytes of Example 1, Example 2, Example 3, and the comparative example were tested using the following test method:

[0168] 10-hour rate capacity test: After the fully charged battery is charged for 1 hour to 24 hours, 10 (A) Current discharge, the battery ambient temperature is maintained between 20 ~ 25 ℃. The change in current value during the discharge time should not exceed 1%. When the battery cell voltage reaches 1.80V, stop discharging and record the discharge time to calculate the discharge capacity.

[0169] -40℃ low temperature capacity test: Place the fully charged battery in a -40℃±2℃ environment for 20 hours. 10 (A) Discharge with a current. During the discharge process, the ambient temperature of the battery is maintained between -40°C ± 2°C, and the change in the current value should not exceed 1%. When the battery cell voltage reaches 1.80V, stop discharging and record the discharge time to calculate the discharge capacity.

[0170] Cycle life test: The battery ambient temperature is kept between 20 and 25 degrees Celsius. 10 (a) Discharge the battery until the cell voltage reaches 1.80V; b) Limit the voltage to 2.35V / cell and charge at 2.5I10(A) for 12 hours; c) Repeat steps a) and b). (The life test terminates when the discharge time in step a is less than 8 hours.)

[0171]

[0172] From the above, it can be seen that Figure 1-3 As shown, when comparing the schemes of Examples 1 to 3 with the comparative example, under conditions of similar 10-hour rate capacities, the lead dioxide content in the positive plate did not cause poor formation due to the addition of calcium sulfate, achieving the same results as the comparative example, while also demonstrating better low-temperature performance and cycle life. The lead paste and preparation method of the present invention can achieve even better low-temperature performance and cycle life. The present invention has simple components, low production costs, and the resulting battery has excellent low-temperature resistance and cycle life, making it widely applicable.

[0173] The above embodiments are only intended to help understand the method and core concept of the present invention. It should be noted that, without departing from the principles of the present invention, a number of improvements and modifications may be made to the present invention by those skilled in the art, and such improvements and modifications also fall within the scope of protection 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 includes a positive lead paste and a positive grid, wherein the positive lead paste includes 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. 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 includes 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 compound, 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 oxide powder in the positive electrode lead paste and the negative electrode lead paste has an oxidation degree of 72-80%, a particle size of ≤5 μm, and a particle size of ≤30 μm; the mixed carbon material in the positive electrode lead paste and the negative electrode lead paste includes graphite, acetylene black, and graphene; the sodium compound is one or more of sodium citrate stannate, sodium stannate, sodium tetraborate, sodium sulfate, sodium silicate, sodium sulfide, sodium polyacrylate, sodium tripolyphosphate, sodium dimercaptosuccinate, sodium dodecylbenzenesulfonate, sodium polyfluoroalkylsulfonate, 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. Deionized water and sulfuric acid are added into a paste mixing machine, and the mixture is mixed with water and acid respectively, thereby preparing a 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 ball mill speed is 200-300 rpm, and the premixing time is 0.5-1h; the dry mixing time in S2 is 1-5min, and the dry mixing time in step 3 is 5-10min; in S4, water mixing and acid mixing are carried out 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 carbon black, 5-10 parts deionized water, and 0.1-0.2 parts sodium hydroxymethyl cellulose; S2. Apply the positive electrode lead paste evenly to the positive electrode alloy grid; S3. Spraying carbon black aqueous solution on the surface of the lead paste, rinsing with acid, drying the surface and then performing curing treatment 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 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 4-5 hours; Step b: relative humidity is 85-90%, temperature is 70-76°C, and control time is 6-8 hours; Step c: relative humidity is 85-90%, temperature is 50-55°C, and control time is 16-18 hours; Step d: The relative humidity is 5-20%, the temperature is 75-80°C, and the 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, then reduce and increase the pressure, mix thoroughly, and dry to obtain a mixture B; S2. Add mixture B, barium sulfate and sodium sulfate in proportion to each other in a ball mill and mix them to obtain mixture C; S3. Add the adhesive to deionized water and dissolve it in a certain proportion to prepare an adhesive solution; S4. Add 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 increased to 0.1MPa. After thorough mixing, the solution is dried at a drying temperature of ≥60°C and a time of 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. The adhesive 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. 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 a certain proportion to obtain a mixture D. S3. Add mixture D to deionized water, heat and stir. After the temperature reaches the set temperature, stop heating, continue stirring until the solution is evenly cooled to room temperature, and obtain mixed solution E. S4, add deionized water to the colloidal 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 prepare 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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