Positive electrode plate and manufacturing method thereof

Abstract

The present invention discloses a positive electrode plate and a manufacturing method thereof, relating to the technical field of lead-acid batteries. While ensuring product quality, the present invention utilizes a high-aperture-density lead paste formula, incorporating a strongly acidic styrene-based cation exchange resin. The lead paste exhibits excellent fluidity, and coupled with an acid-free, rapid paste-mixing process, no excess water is precipitated during the paste extrusion process, eliminating the need for a supporting lead paste recovery and processing system. Furthermore, the lead paste formula does not contain sulfuric acid, resulting in no chemical reaction. Therefore, the paste-mixing equipment eliminates the need for water or air cooling or the use of acid-resistant, corrosion-resistant materials, thereby reducing the manufacturing cost of the paste-mixing equipment. Furthermore, the positive electrode plate curing process is eliminated, simplifying the processing technology and reducing battery production costs. Lead-acid batteries assembled using the positive electrode plates manufactured using the present invention exhibit significantly improved high-rate discharge performance.

Description

Technical Field

[0001] The present invention relates to the technical field of lead-acid batteries, and in particular to a positive electrode plate and a manufacturing method thereof. Background Art

[0002] There are three main methods for manufacturing positive plates for tubular lead-acid batteries: powder filling, paste extrusion, and grouting. The paste extrusion method involves extruding lead paste into a pre-prepared tubular grid (with sleeves installed on the grid's ribs). This process requires specialized extrusion equipment, which squeezes the pre-mixed lead paste into the tubular grid at a specific pressure and speed. The grid is then sealed with a bottom seal and sent to a curing and drying kiln for curing and drying.

[0003] When the lead paste is squeezed into the tubular grid, in order to ensure uniform distribution and filling rate of the lead paste in the grid, it is necessary to control the extrusion pressure, speed, fluidity of the lead paste and other parameters. If the fluidity of the lead paste is poor and the extrusion pressure is too high, it may cause the casing of the tubular grid to rupture or deform, and the active material to leak, resulting in battery short circuit or increased self-discharge. It may also cause uneven paste extrusion, resulting in flat tubes or empty tubes. Therefore, in order to produce a lead paste with good fluidity, the apparent density of the lead paste is generally controlled at 3.2-3.7g / cm 3 However, at this density, the moisture content in the lead paste is high. When the lead paste is squeezed into the tubular grid, some of the moisture in the lead paste will precipitate from the holes in the casing under the action of pressure (the apparent density of the lead paste in the casing is 4.8-5.1g / cm 3 ), the precipitated water is accompanied by a lot of lead sludge, making the casing surface dirty and requiring cleaning. If cleaning is not thorough, it will increase the internal resistance of the battery and reduce battery performance. Therefore, under normal circumstances, the casing surface is cleaned with a large amount of water and equipped with a dedicated lead paste recovery and processing system.

[0004] The lead paste recycling and treatment system primarily consists of a recovery tank, a sedimentation tank, a clean water tank, and a mixing tank. The recovery tank is equipped with a mixing system that must operate continuously to prevent lead sludge sedimentation. The sedimentation tank is equipped with a clean water and lead sludge separation device. The separated lead sludge is pumped into the mixing tank, and clean water is pumped into the clean water tank. The mixing tank is equipped with a stirring system that thoroughly mixes the lead sludge with an appropriate amount of clean water. When the density reaches the process requirement, the mixture in the mixing tank is then transferred to the paste mixing machine in a specified dosage. This lead paste recycling and treatment system achieves zero-emission sludge recycling, but its operation is complex, introducing significant inconveniences in production and operation. This is especially true for the lead pump in the mixing system, which must operate continuously to prevent lead sludge sedimentation. This places higher demands on equipment reliability and also wastes significant energy.

[0005] In addition, the traditional lead paste extrusion process uses a lead paste formula that mainly includes lead powder, sulfuric acid, water, and additives. During the lead paste preparation process, sulfuric acid reacts chemically with lead powder, releasing a large amount of heat. To prevent the paste temperature from exceeding 60°C, the acid addition time is usually controlled within 15-20 minutes. Therefore, the time required to prepare a box of lead paste is not less than 30 minutes. The requirements for the paste preparation equipment are also relatively high. It must be resistant to acid corrosion and equipped with two sets of cooling devices, air cooling and water cooling. At the same time, when the lead paste produced by this process reacts with sulfuric acid, basic lead sulfate is generated, making the lead paste structure more compact and relatively hard. When the apparent density of the lead paste is higher than 3.8g / cm 3 When the needle penetration of the lead paste is less than 45mm, the process performance during paste extrusion is not ideal, and it is easy to have phenomena such as expanded tubes, empty tubes, flat tubes, and the amount of paste extruded is not within the process requirements.

[0006] Therefore, it is urgent to develop a new manufacturing method to solve the above problems existing in the existing manufacturing method of positive electrode plates. Summary of the Invention

[0007] The technical problem to be solved by the present invention is: to overcome the shortcomings of the existing technology, provide a positive electrode plate and a manufacturing method thereof, adopt a high apparent density lead paste formula and an acid-free rapid paste mixing process while ensuring product quality, no excess water is analyzed out during the paste squeezing process, and no supporting lead paste recovery and processing system is required; at the same time, the positive electrode plate curing process is eliminated, the processing technology is simplified, and the battery production cost is reduced; the lead-acid battery assembled with the positive electrode plate manufactured by the present invention has greatly improved high-rate discharge performance.

[0008] The technical solution of the present invention is:

[0009] In one aspect, the present invention provides a method for manufacturing a positive electrode plate, comprising the following steps:

[0010] S1: preparing lead paste: the lead paste is made of the following raw materials in parts by weight: 100 parts of lead powder, 4-5 parts of strong acid styrene cation exchange resin, 0.5-1 parts of nano-silica and 9.3-10.5 parts of deionized water; the preparation method of the lead paste is as follows: adding the strong acid styrene cation exchange resin, nano-silica and 50 parts of lead powder to a paste mixing machine, and performing a first stage of stirring; then adding the remaining 50 parts of lead powder, and performing a second stage of stirring; then pouring deionized water into the paste mixing machine, and performing a third stage of stirring while pouring water, and the stirring speed of the three stages is gradually increased, so that the apparent density is 4.8-5.1g / cm 3 lead paste;

[0011] S2 acid dipping: squeeze the lead paste into the tubular grid and install the bottom seal. The dipping density is 1.6-1.65g / cm 3 sulfuric acid electrolyte;

[0012] S3 drying: After acid soaking, it is sent to the drying kiln for drying. The humidity of the first drying stage is 60-75% RH, the temperature is 50-60℃, and the time is 6-8h; the humidity of the second drying stage is ≤20% RH, the temperature is 70-80℃, and the time is 16-18h, and the positive plate is obtained.

[0013] Preferably, in step S1, the strongly acidic styrene-based cation exchange resin is a 001X7H strongly acidic styrene-based cation exchange resin.

[0014] Preferably, in step S1, the particle size of the strongly acidic styrene-based cation exchange resin is 0.3-0.6 mm.

[0015] Preferably, in step S1, the stirring speed in the first stage is 15-20 rpm, so that the strong acid styrene cation exchange resin evenly coats the lead powder; the stirring speed in the second stage is 30-40 rpm, forming a "lead powder-resin" core-shell structure; and the stirring speed in the third stage is 60-80 rpm, triggering the strong acid styrene cation exchange resin to swell and release lubricity.

[0016] Preferably, the stirring time in the first stage is 1-1.5 min, the stirring time in the second stage is 1-1.5 min, the deionized water pouring time is 3-5 min, and the stirring time in the third stage is 5-8 min.

[0017] Preferably, in step S1, the total time for mixing the paste is 7-11 minutes.

[0018] Preferably, in step S2, the pickling time is 3-5s.

[0019] In another aspect, the present invention provides a positive electrode plate manufactured by the above-mentioned method for manufacturing a positive electrode plate.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The lead paste of the present invention is manufactured by a high apparent density lead paste formula and an acid-free, rapid paste-making process, and has good fluidity. When the lead paste is squeezed into the tubular grid, the moisture in the lead paste will not precipitate from the holes of the sleeve under the action of pressure. The sleeve surface is clean and does not need to be cleaned. Therefore, there is no need for a supporting lead paste recovery and processing system, which simplifies the paste extrusion process.

[0022] 2. The acid-free rapid paste-making process of the present invention significantly shortens the paste-making time, improving equipment utilization. Furthermore, since sulfuric acid is not required during the lead paste manufacturing process, the paste-making equipment does not need to be acid-proofed or made of acid-proof materials, reducing equipment manufacturing costs.

[0023] 3. The lead-acid battery assembled with the positive plate manufactured by the present invention is comparable to the lead-acid battery manufactured by the traditional process, and has better high-rate discharge performance. This is because the H in the pores of the traditional positive plate is + The concentration decreases rapidly, but the H + The lack of acid in the plate leads to stagnation of the reaction, a sudden drop in voltage ("knee effect"), and premature termination of discharge. When the present invention uses a strong acid styrene-based cation exchange resin as an additive, its mechanism of action is as follows: When the battery is discharged at a high rate, due to the H + When the concentration drops rapidly and the diffusion rate of sulfuric acid cannot keep up, the H + With Pb in solution 2+ Exchange occurs, adsorption of Pb 2+ , release H + , thereby increasing the positive plate micropore H + The concentration of H increases the discharge capacity. During the discharge and charging process, due to diffusion, the H in the micropores of the positive electrode active material + The concentration gradually increased and the Pb adsorbed by the strong acid styrene cation exchange resin 2+ Exchange occurs, restoring the strongly acidic styrene cation exchange resin to its original state.

[0024] 4. The present invention adds nano-silica to the lead paste formula of the positive electrode. The hydroxyl groups on its surface form a hydrogen bond network with the sulfonic acid groups of the strong acid styrene-based cation exchange resin. Water molecules are bound in the hydrogen bond network, preventing the lead paste from dehydrating too quickly and avoiding the problem of high-density lead paste drying and cracking.

[0025] 5. The present invention is achieved by (1) high density (1.6-1.65g / cm 3 ) Sulfuric acid rapidly sulfonates the surface of the lead paste within 3-5 seconds, forming a dense PbSO4 layer, which can enhance the mechanical strength of the positive plate; (2) In the first drying stage, the strong acid styrene-based cation exchange resin absorbs heat and expands, and the internal moisture gradient diffuses. In the second drying stage, the strong acid styrene-based cation exchange resin dehydrates and shrinks, squeezing the lead powder particles and enhancing the bonding force, thereby achieving the performance of the positive plate manufactured after eliminating the curing process is not lower than that of the traditional cured product, simplifying the production process. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0027] In the following embodiments:

[0028] 001X7H strong acid styrene cation exchange resin, Zibo Dongda Chemical Co., Ltd.;

[0029] Nano-silicon dioxide, Wuxi Hengcheng Silicon Industry Co., Ltd.;

[0030] Lead powder, homemade in the laboratory.

[0031] Example 1

[0032] The manufacturing method of the 5DB500 positive electrode plate of this embodiment includes the following steps:

[0033] S1 Preparation of lead paste: Add 40 kg of 001X7H type strong acid styrene cation exchange resin (particle size 0.3 mm), 5 kg of nano-silica and 500 kg of lead powder to the paste mixer and stir at 15 rpm for 1 min; then add 500 kg of lead powder and stir at 30 rpm for 1 min; then pour 93 kg of deionized water into the paste mixer for 3 minutes. While pouring water, adjust the stirring speed to 60 rpm and stir at this speed for 5 minutes. Stop the machine to test the apparent density of the lead paste, which is 5.1 g / cm 3 , you get lead paste;

[0034] S2 acid dipping: Use the die-casting mold of 5DB500 lead-acid battery to die-cast 4800 positive grids. Use the casing machine to install the ribs of the die-cast positive grid in the polyester tube. Send the semi-finished positive grid with the polyester tube installed to the paste extruder, squeeze in the lead paste, the amount of paste extruded is 1468g / piece, and then automatically install the plastic bottom to obtain the wet positive plate; put the wet positive plate into the slurry containing sulfuric acid with a density of 1.6g / cm 3 Soak the positive plates in an acid tank for 3 seconds. After soaking, take out the positive plates and place them on a drying rack.

[0035] S3 Drying: Send the drying rack with the positive plates to the drying kiln for drying. The humidity of the first drying stage is 60% RH, the temperature is 50℃, and the time is 6 hours. The humidity of the second drying stage is 20% RH, the temperature is 70℃, and the time is 16 hours. The positive plates are obtained, and the moisture content of the positive plates is 0.5wt.%.

[0036] The positive electrode plates manufactured in this embodiment were assembled into a lead-acid battery of model 5DB500.

[0037] Example 2

[0038] The manufacturing method of the 5PzS625 positive electrode plate of this embodiment includes the following steps:

[0039] S1 Preparation of lead paste: Add 45 kg of 001X7H type strong acid styrene cation exchange resin (particle size 0.45 mm), 7.5 kg of nano-silica and 500 kg of lead powder to a paste mixer and stir at 17.5 rpm for 1.25 min; then add 500 kg of lead powder and stir at 35 rpm for 1.25 min; then pour 97 kg of deionized water into the paste mixer for 4 min. While pouring water, adjust the stirring speed to 70 rpm and stir at this speed for 6.5 min. Stop the machine to test the apparent density of the lead paste, which is 4.95 g / cm 3 , you get lead paste;

[0040] S2 acid dipping: Use the die-casting mold of 5PzS625 lead-acid battery to die-cast 2400 positive grids. Use the casing machine to install the ribs of the die-cast positive grid in the polyester tube. Send the semi-finished positive grid with the polyester tube installed to the paste extruder, squeeze in the lead paste, the paste amount is 1810g / piece, and then automatically install the plastic bottom to obtain the wet positive plate; put the wet positive plate into the slurry containing sulfuric acid with a density of 1.65g / cm 3 Soak the positive plates in an acid tank for 4 seconds. After soaking, take out the positive plates and place them on a drying rack.

[0041] S3 Drying: Send the drying rack with the positive plates to the drying kiln for drying. The humidity of the first drying stage is 67% RH, the temperature is 55°C, and the time is 7 hours. The humidity of the second drying stage is 15% RH, the temperature is 75°C, and the time is 17 hours. The positive plates are obtained, and the moisture content of the positive plates is 0.4wt.%.

[0042] The positive electrode plates manufactured in this embodiment were assembled into a lead-acid battery of model 5PzS625.

[0043] Example 3

[0044] The manufacturing method of the D-450 positive electrode plate of this embodiment includes the following steps:

[0045] S1 Preparation of lead paste: Add 50 kg of 001X7H type strong acid styrene cation exchange resin (particle size 0.6 mm), 10 kg of nano-silica and 500 kg of lead powder to a paste mixer and stir at 20 rpm for 1.5 min; then add 500 kg of lead powder and stir at 40 rpm for 1.5 min; then pour 105 kg of deionized water into the paste mixer for 5 min. While pouring water, adjust the stirring speed to 80 rpm and stir at this speed for 8 min. Stop the machine to test the apparent density of the lead paste, which is 4.8 g / cm 3 , you get lead paste;

[0046] S2 acid dipping: Use the die-casting mold of D-450 lead-acid battery to die-cast 4800 positive grids. Use the casing machine to install the ribs of the die-cast positive grid in the polyester tube. Send the semi-finished positive grid installed with the polyester tube to the paste extruder, squeeze in the lead paste, the amount of paste extruded is 730g / piece, and then automatically install the plastic bottom to obtain the wet positive plate; put the wet positive plate into the slurry containing sulfuric acid with a density of 1.65g / cm 3 Soak the positive plates in an acid tank for 5 seconds. After soaking, take out the positive plates and place them on a drying rack.

[0047] S3 Drying: Send the drying rack with the positive plates to the drying kiln for drying. The humidity of the first drying stage is 75% RH, the temperature is 60℃, and the time is 8h. The humidity of the second drying stage is 10% RH, the temperature is 80℃, and the time is 18h. The positive plates are obtained, and the moisture content of the positive plates is 0.25wt.%.

[0048] The positive electrode plates manufactured in this embodiment were assembled into a lead-acid battery of model D-450.

[0049] Comparative Example 1

[0050] The manufacturing method of the 5DB500 positive electrode plate of Comparative Example 1 comprises the following steps:

[0051] S1 manufactures recycled lead paste: transports the lead sludge and clean water from the lead paste recycling system to the mixing tank and adjusts its density to 1.8g / cm 3 stand-by;

[0052] S2: Make lead paste: add 500kg lead powder and 500kg red lead into the paste making machine and stir at 50rpm for 3min; add 110kg deionized water and stir at 50rpm for 3min; while stirring, add 100kg of 1.4g / cm 3 Add sulfuric acid to the paste machine and continue stirring for 10 minutes after the acid addition to obtain the lead paste. The apparent density of the lead paste is 4.25g / cm 3 To prevent the paste machine temperature from exceeding 60°C during the paste mixing process, it is necessary to open the paste machine cooling water and air cooling systems starting from the sulfuric acid addition stage. When the lead paste temperature in the paste machine is lower than 38°C, add 220kg of the recycled lead paste from step S1 into the paste machine and continue stirring at 50rpm for 10min. The apparent density of the lead paste is 3.2g / cm 3 ;

[0053] S3 Paste Extrusion: Using the die-casting mold of the 5DB500 lead-acid battery, 4,800 positive grids are die-cast. The ribs of the die-cast positive grids are installed in polyester tubes using a casing machine. The semi-finished positive grids with polyester tubes installed are sent to the paste extruder, where lead paste is squeezed in at a rate of 1,590 g per piece. The plastic bottom is then automatically installed to obtain wet positive plates. The wet positive plates are then sent to a cleaning station to clean the lead mud on the surface of the positive plates.

[0054] S4 curing and drying: The wet positive electrode plates after surface cleaning are sent to a curing and drying kiln, and the positive electrode plates are cured and dried according to the curing and drying parameters shown in Table 1-2 to obtain positive electrode plates, and the moisture content of the positive electrode plates is 0.5wt.%.

[0055] Table 1 Curing parameters of the positive electrode plate of Comparative Example 1

[0056]

[0057] Table 2 Drying parameters of the positive plate of Comparative Example 1

[0058]

[0059] The positive electrode plates manufactured in Comparative Example 1 were assembled into a lead-acid battery of model 5DB500.

[0060] Comparative Example 2

[0061] The difference from Example 1 is that in step S1, 001X7H type strong acid styrene cation exchange resin is not added.

[0062] Comparative Example 3

[0063] The difference from Example 1 is that in step S1, D201 type strong basic anion exchange resin (particle size 0.3 mm) is used instead of 001X7H type strong acid styrene type cation exchange resin in Example 1.

[0064] Comparative Example 4

[0065] The difference from Example 1 is that in step S1, the added amount of 001X7H type strong acid styrene-based cation exchange resin is 55 kg.

[0066] Comparative Example 5

[0067] The difference from Example 1 is that in step S1, no nano-silicon dioxide is added.

[0068] Comparative Example 6

[0069] The difference from Example 1 is that in step S1, the amount of nano-silicon dioxide added is 15 kg.

[0070] Comparative Example 7

[0071] The difference from Example 1 is that in step S1, 001X7H type strong acid styrene-based cation exchange resin, nano-silica, lead powder and deionized water are added to the paste making machine at one time and stirred together at a stirring speed of 60 rpm.

[0072] Comparative Example 8

[0073] The difference from Example 1 is that in step S1, the stirring speed of the paste mixing machine is always 80 rpm.

[0074] Comparative Example 9

[0075] The difference from Example 1 is that in step S1, the amount of deionized water poured in is 72.5 kg, and the apparent density of the obtained lead paste is 5.5 g / cm 3 .

[0076] Comparative Example 10

[0077] The difference from Example 1 is that in step S2, the density of sulfuric acid in the acid tank is 1.75 g / cm 3 .

[0078] Comparative Example 11

[0079] The difference from Example 1 is that in step S3, the drying rack on which the positive plates are placed is sent to a drying kiln for drying at a humidity of 20% RH, a temperature of 70°C, and a drying time of 22 hours to obtain positive plates, and the moisture content of the positive plates is 0.01 wt.%.

[0080] The performance of the lead-acid batteries assembled from Examples 1-3 and Comparative Examples 1-11 was tested in accordance with GB / T 7403.1-2018 Lead-acid Batteries for Traction Part 1: Technical Requirements. The test results are shown in Table 3.

[0081] Table 3 Performance test results of lead-acid batteries assembled from Examples 1-3 and Comparative Examples 1-11

[0082]

[0083] In Table 3, first-discharge capacity / rated capacity refers to the percentage of actual capacity to rated capacity during the first capacity test; discharge capacity / rated capacity refers to the percentage of the highest actual capacity to rated capacity during the first ten capacity tests.

[0084] As shown in Table 3, the initial capacities of the lead-acid batteries of Examples 1-3 and Comparative Example 1 all meet the requirements of GB / T 7403.1-2018 Lead-acid Batteries for Traction Use - Part 1: Technical Requirements. Furthermore, compared to the lead-acid battery manufactured using conventional manufacturing methods in Comparative Example 1, the lead-acid batteries of Examples 1-3 have comparable capacities and exhibit superior high-rate discharge performance. Furthermore, because the positive plates were not cured during the manufacturing process of Examples 1-3, the processing was simplified.

[0085] Compared with Example 1, the first capacity of the lead-acid battery manufactured in Comparative Example 2 and the highest capacity in the first ten capacity tests are basically the same, but the high-rate discharge performance decreases by about 13.6%, indicating that the addition of a strong acid styrene-based cation exchange resin can improve the rate discharge performance. The first capacity of the lead-acid battery manufactured in Comparative Example 3 and the highest capacity in the first ten capacity tests and the high-rate discharge performance are all significantly reduced. This is because the anions on the D201 strong base anion exchange resin react with SO4 in the electrolyte. 2- Competing for transmission channels, lead ions and SO4 2- Combined with forming PbSO4 reaction is hindered, affects the charge-discharge performance of battery.The first time capacity of the lead-acid battery that comparative example 4 makes and the highest capacity in the first ten capacity tests and high rate discharge performance are suitable with embodiment 1, illustrate that strongly acidic styrene-based cation exchange resin adds too much and does not improve the performance of battery, on the contrary increases manufacturing cost.The first time capacity of the lead-acid battery that comparative example 5 makes and the highest capacity in the first ten capacity tests and high rate discharge performance all obviously reduce, and during the first ten capacity tests, capacity does not reach standard requirement value, illustrate that the lead plaster that does not add nano silicon dioxide, drying speed is fast, makes the lead plaster shrink uneven, and the pole plate surface lead plaster cracks, affects battery capacity.The first time capacity of the lead-acid battery that comparative example 6 makes and the highest capacity in the first ten capacity tests and high rate discharge performance all obviously reduce, and high rate discharge performance does not reach standard requirement, and this is because nano silicon dioxide itself is insulating, and excessive adding may cause the electrode overall electrical conductivity to descend.

[0086] Compared with Example 1, the first time capacity of the lead-acid battery that Comparative Example 7 manufactures and the highest capacity in the first ten capacity tests and high rate discharge performance all obviously reduce, and the first time capacity is the highest, illustrate that the lead paste that this and paste mode obtain, composition is uneven, has affected the performance of battery.The first time capacity of the lead-acid battery that Comparative Example 8 manufactures and the highest capacity in the first ten capacity tests and high rate discharge performance slightly reduce, illustrate that the dry mixing stirring speed before adding water is too high, makes part strong acid styrene type cation exchange resin damaged, has affected the performance of battery.The first time capacity of the lead-acid battery that Comparative Example 9 manufactures and the highest capacity in the first ten capacity tests and high rate discharge performance all obviously reduce, and the highest capacity in the first ten capacity tests does not meet standard requirement, because adopt the lead paste of this process to manufacture, because lead paste apparent density is too high, paste squeezing difficulty, bulging tube, empty tube phenomenon occur in the positive plate of manufacture, has affected the capacity of battery. The first capacity of the lead-acid battery manufactured in Comparative Example 10, the highest capacity in the first ten capacity tests, and the high-rate discharge performance were all significantly reduced. This is because when the pickling density is increased, the lead sulfate layer formed on the surface becomes thicker, and the lead sulfate on the surface is difficult to be completely decomposed and converted into lead dioxide during the battery formation process, resulting in a decrease in battery capacity. The first capacity of the lead-acid battery manufactured in Comparative Example 11, the highest capacity in the first ten capacity tests, and the high-rate discharge performance were all significantly reduced, and the highest capacity in the first ten capacity tests did not meet the standard requirements. This is because the excessively high drying temperature causes a dense layer to form on the surface of the plate, hindering the uniform penetration of sulfuric acid during subsequent battery formation, resulting in incomplete formation, reduced active material utilization, and reduced battery capacity. At the same time, due to the addition of nano-silicon dioxide to the lead paste, the water content of the green plate (wet state) manufactured during the paste extrusion is about 15wt.%. Using a single drying method to lose water too quickly may also cause the nano-silicon dioxide to deteriorate in dispersion, form agglomerates, destroy the pore structure of the plate, and reduce its effect of improving battery performance.

Claims

1. A method for manufacturing a positive electrode plate, characterized in that: The following steps are involved: S1: preparing lead paste: the lead paste is made of the following raw materials in parts by weight: 100 parts of lead powder, 4-5 parts of strong acid styrene cation exchange resin, 0.5-1 parts of nano-silica and 9.3-10.5 parts of deionized water; the preparation method of the lead paste is as follows: adding the strong acid styrene cation exchange resin, nano-silica and 50 parts of lead powder to a paste mixing machine, and performing a first stage of stirring; then adding the remaining 50 parts of lead powder, and performing a second stage of stirring; then pouring deionized water into the paste mixing machine, and performing a third stage of stirring while pouring water, and the stirring speed of the three stages is gradually increased, so that the apparent density is 4.8-5.1g / cm 3 lead paste; S2 acid dipping: squeeze the lead paste into the tubular grid and install the bottom seal. The dipping density is 1.6-1.65g / cm 3 sulfuric acid electrolyte; S3 drying: After acid soaking, it is sent to the drying kiln for drying. The humidity of the first drying stage is 60-75% RH, the temperature is 50-60℃, and the time is 6-8h; the humidity of the second drying stage is ≤20% RH, the temperature is 70-80℃, and the time is 16-18h, and the positive plate is obtained.

2. The method for manufacturing a positive electrode plate according to claim 1, wherein: In step S1, the strongly acidic styrene-based cation exchange resin is a 001X7H strongly acidic styrene-based cation exchange resin.

3. The method for manufacturing a positive electrode plate according to claim 1, wherein: In step S1, the particle size of the strongly acidic styrene-based cation exchange resin is 0.3-0.6 mm.

4. The method for manufacturing a positive electrode plate according to claim 1, wherein: In step S1, the stirring speed in the first stage is 15-20 rpm, the stirring speed in the second stage is 30-40 rpm, and the stirring speed in the third stage is 60-80 rpm.

5. The method for manufacturing a positive electrode plate according to claim 4, wherein: The stirring time in the first stage is 1-1.5 minutes, the stirring time in the second stage is 1-1.5 minutes, the deionized water pouring time is 3-5 minutes, and the stirring time in the third stage is 5-8 minutes.

6. The method for manufacturing a positive electrode plate according to claim 5, wherein: In step S1, the total time for mixing the paste is 7-11 minutes.

7. The method for manufacturing a positive electrode plate according to claim 1, wherein: In step S2, the pickling time is 3-5s.

8. Positive electrode, characterized in that: The positive electrode plate is manufactured by the manufacturing method according to any one of claims 1 to 7.

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