WO2022174585A1

WO2022174585A1 - Method for preparing positive plate and lead storage battery

Info

Publication number: WO2022174585A1
Application number: PCT/CN2021/119491
Authority: WO
Inventors: 庄建; 张天任; 周建中; 欧阳万忠; 陈勤忠; 周文渭; 房兆锟
Original assignee: 天能电池集团股份有限公司
Priority date: 2021-02-22
Filing date: 2021-09-22
Publication date: 2022-08-25
Also published as: CN112786898A; CN112786898B

Abstract

The present application relates to the technical field of lead storage batteries and discloses a method for preparing a positive plate and a lead storage battery. The method for preparing a positive plate comprises the following steps: (1) preparing a positive plate grid; (2) soaking of the positive plate grid: soaking the positive plate grid in a cobalt phosphate suspension containing 100 parts of pure water and 3-5 parts of cobalt phosphate; (3) drying and cooling of the positive plate grid: first putting the soaked positive plate grid in an environment having a relative humidity of 70%-80% and a temperature of 50-60°C for standing for 3-5 h, then putting same in an environment having a relative humidity of 30%-40% and a temperature of 50-60°C for standing for 5-8 h, and finally putting same in an environment having a relative humidity of 30%-40% for lowering the temperature to room temperature within 2 h; (4) preparing a paste; and (5) coating. The positive plate grid prepared in the present application is more corrosion-resistant, and the discharge cycle service life of the prepared lead storage battery is prolonged.

Description

A kind of preparation method of positive plate, lead storage battery

technical field

The application relates to the technical field of lead storage batteries, in particular to a method for preparing a positive plate and a lead storage battery.

Background technique

G. Plante invented the lead-acid battery in 1859, and has experienced nearly 160 years of development. The lead-acid battery has made great progress in theoretical research, product types and product electrical performance. Lead-acid batteries can be classified into lead-acid batteries for starting, backup-use lead-acid batteries, lead-acid batteries for energy storage, and lead-acid batteries for power use, etc., according to their uses. However, due to the different use conditions and occasions of various lead-acid batteries, the reasons for battery failure are also different. Even the same type of battery failure mode is the same for each part. For example, the lead-acid battery used for starting motorcycles is used for a long time. The failure modes of the battery during the daytime are mostly water loss and corrosion of the positive grid. When driving at night, the lighting battery is added. Most of the failure modes are insufficient charging, negative electrode vulcanization, etc.

Compared with starting batteries, energy storage batteries, and power batteries, backup batteries are charging throughout their entire life cycle. As a starting battery for motorcycles and automobiles, it is only charged when the vehicle is working; the battery for energy storage is affected by the time, angle, and wind power of the sun, and the battery is undercharged in most cases; the charging and discharging of the power battery are carried out separately, and normal charging The time in the high voltage area is 4 to 7 hours, and many users can ride for many days on a single charge.

The backup battery is generally charged by the mains power supply through the transformer device, and is only used in emergencies such as power failure, equipment maintenance, etc., so the battery is charged during the life cycle. When the battery is charging, the positive electrode of the battery has a high charging potential, and the positive electrode grid is prone to electrochemical corrosion. In order to obtain sufficient life of the backup battery, the general measures of the battery factory are to use thick plates to increase the floating life of the lead-acid battery.

Patent document CN109921022A discloses a method for improving the bonding force between the positive electrode grid of a lead-acid battery and the lead paste and the firmness of the lead paste itself. The main step is to dry the conventional positive grid at a certain temperature for a period of time. At the same time, add 0.025-0.125 g of additives to distilled water with a volume of 5-8 ml, and stir to form solution A. Then, add solution A to the fully ground lead powder, and then slowly add dilute sulfuric acid. After stirring, the positive lead paste is prepared. Take out the heat-treated positive electrode grid, apply the obtained lead paste evenly on it, then, after natural drying, make a positive electrode green plate, and finally, after forming it for 5 hours, the prepared positive electrode cooked plate is obtained. . The lead-acid battery positive plate obtained by the invention has no obvious peeling and peeling phenomenon under the same use conditions, has good cycle stability, and can significantly improve the service life of the lead-acid battery. The lead-acid battery prepared in this patent document is only aimed at the fact that the positive plate does not fall off under normal use conditions.

Patent document CN101841031B discloses a method for making a positive grid of a lead battery, which belongs to the technical field of electrode material preparation. Lead alloy is used as a raw material, and a lead alloy positive grid formed by melting and casting is used as an anode. The anode electrochemical oxidation method is used for surface modification, and rare earth is used to improve the performance of the surface of the lead alloy positive grid. The invention avoids the difficulty of preparing lead-rare earth alloys, and it is easy to uniformly and quantitatively mix some trace rare earth elements on the surface of the lead alloy positive electrode grid, so as to realize the regulation of electrode surface properties, and the electrochemical preparation of rare earth oxides has the operating conditions of rare earth oxides. It has the advantages of mildness, simplicity, low preparation cost, high purity of the prepared rare earth oxide, and adjustable microdomain structure of the rare earth oxide. The invention enables the lead alloy positive grid electrode to have good electrical and chemical properties and long service life, and is also beneficial to the production of the positive grid of the low-cost lead storage battery. The grid produced in this patent document needs to be electrochemically modified, the actual operation process is complicated, and the fabrication cost is high.

SUMMARY OF THE INVENTION

In order to solve the problem of the lifespan of a lead storage battery under long-term floating charging conditions, the present application discloses a preparation method of a positive plate and a lead storage battery.

A preparation method of a positive plate, comprising the following steps:

(1) Preparation of positive grid;

(2) Immersion of the positive grid,

According to the mass ratio, every 100 parts of pure water and 3 to 5 parts of cobalt phosphate are prepared into a cobalt phosphate suspension, and the positive grid is placed in the cobalt phosphate suspension to soak;

(3) Drying and cooling of the positive grid,

The immersed positive grid is first kept for 3h to 5h under the conditions of relative humidity of 70% to 80% and temperature of 50 to 60°C, and then placed under the conditions of relative humidity of 30% to 40% and temperature of 50 to 60°C. Under the condition of standing for 5 to 8 hours, a corrosion layer is formed on the surface of the grid, and the cobalt phosphate particles are attached to the outside of the corrosion layer. Finally, the temperature is lowered to room temperature within 2 hours under the condition of relative humidity of 30% to 40%;

(4) and paste to prepare positive lead paste;

(5) Coating, apply the positive lead paste to the positive grid.

In step (1), the alloy lead is first melted and then made into a lead strip, which is then rolled, punched, and knurled to obtain a positive grid.

The thickness of the lead strip after rolling is 2.2-3.2 mm, and the depth of the knurling is 0.1-0.15 mm.

In step (2), after heating to raise the temperature of the cobalt phosphate suspension to 45-55°C, the positive grid is immersed in the cobalt phosphate suspension, and heated to raise the water temperature to 45-55°C.

The purpose of heating is to improve the solubility of cobalt phosphate, but the effect is not obvious and has a certain effect. The purpose of soaking the cobalt phosphate on the positive grid is to attach cobalt phosphate particles on the surface of the grid, and the amount of cobalt phosphate attached has nothing to do with the soaking time.

Coating was carried out within 8 hours after drying and cooling was completed.

The mixing process of the positive lead paste is as follows: firstly mix and stir lead powder and fibers that account for 0.08% to 0.10% of the mass of the lead powder, and then add water that accounts for 11.5% of the mass of the lead powder and 8.2% to 9.2% of the mass of the lead powder. 1.40g/mL of sulfuric acid was carried out and paste.

The production process of negative lead paste: lead powder, barium sulfate accounting for 0.8%-1% by mass of lead powder, lignin accounting for 0.1%-0.3% by mass of lead powder, acetylene black accounting for 0.2%-0.4% by mass of lead powder, The fibers accounting for 0.07%-0.1% of the mass of the lead powder are mixed and stirred, and then water, which accounts for 11.3% of the mass of the lead powder, and sulfuric acid and paste, which accounts for 7.6%-8.6% of the mass of the lead powder and has a specific gravity of 1.4g/mL, are added to obtain the negative lead paste. , the negative lead paste is coated on both sides of the negative grid to obtain a negative plate.

This application has the following advantages:

In the present application, the continuous casting positive grid is first soaked in the cobalt phosphate suspension, and then the soaked positive grid is first placed in an environment with a relative humidity of 70% to 80% and a temperature of 50 to 60°C. For 3 to 5 hours, put it in an environment with a relative humidity of 30% to 40% and a temperature of 50 to 60°C for 5 to 8 hours. A corrosion layer is formed on the surface of the grid, and the cobalt phosphate particles are attached to the outside of the corrosion layer. Finally, the grid The temperature was lowered to room temperature within 2 hours in an environment with a relative humidity of 30% to 40%. After the treated positive grid is coated, cured, assembled and charged, cobalt phosphate penetrates into the grid corrosion layer, which increases the density of the grid corrosion film, enhances the bonding force between the positive grid and the active material, and reduces the positive electrode activity. The material softens the risk of falling off and improves the battery's resistance to overcharging.

Detailed ways

Example 1

The positive alloy lead is made into a lead tape with a thickness of 2.5mm, and the 6-GF-100 positive grid with a size of 151mm×151mm is made after punching, and then knurled with a size of 0.5×0.5mm and a depth of 0.12mm deal with.

In terms of mass percentage, mix 100 parts of pure water and 4 parts of cobalt phosphate, heat to raise the temperature of the suspension to 55°C, put the positive grid into the stirring cobalt phosphate suspension, and heat to make the water temperature rise to 55°C. After ℃, take out the positive grid and put it in an environment with a relative humidity of 80% and a temperature of 60 ℃ for 4 hours, and then put the positive grid in an environment with a relative humidity of 40% and a temperature of 60 ℃ for 6.5 hours. Finally, the positive electrode grid is placed in an environment with a relative humidity of 40% for 2 hours, and the temperature is lowered to room temperature to obtain a treated positive electrode grid.

Mix and stir 1T of positive lead powder and 1Kg of fiber, then add 115Kg of pure water, and then add 92Kg of sulfuric acid with a specific gravity of 1.40g/mL to make a paste, depending on the positive lead paste with a specific gravity of 4.30g/cm3. The positive electrode lead paste is coated on the treated positive electrode grid, and the positive electrode green plate is obtained after acid leaching, surface drying, curing, drying, and slice grinding.

Mix and stir 1T of negative lead powder, 10Kg of barium sulfate, 3Kg of lignin, 4Kg of acetylene black and 1Kg of fiber, then add 113Kg of pure water, and then add 86Kg of sulfuric acid with a specific gravity of 1.40g/mL to make a paste, and the apparent specific gravity is 4.40g. /cm3 of negative lead paste. The negative electrode lead paste is coated on the cast negative grid, and the negative electrode green plate is obtained after acid leaching, surface drying, curing, drying and slice grinding.

6-GF-100 long-life lead-acid battery for floating charge was prepared by wrapping, assembling, adding acid, charging, and grouping the prepared positive green plate and negative green plate.

Take one of the above-mentioned lead-acid batteries for 10-hour rate capacity testing, and the results are shown in Table 1. After the above-mentioned lead-acid battery is fully charged, it is continuously charged at a constant voltage of 13.80V for 30 days at a temperature of 60±2°C. 10.50V, calculate the discharge capacity of the battery. The above is a test cycle. When the battery discharge capacity is lower than 80% of the rated capacity, the battery is dissected at the end of the cycle test. The results are shown in Table 2. The last cycle is not included in the battery life cycle.

Example 2

The positive alloy lead is made into a lead tape with a thickness of 3.2mm, and the 6-GF-300 positive grid with a size of 237mm×151mm is made after punching the net, and then knurled with a size of 0.5×0.5mm and a depth of 0.15mm deal with.

In terms of mass percentage, mix 100 parts of pure water and 3 parts of cobalt phosphate, heat to make the temperature of the suspension rise to 45°C, put the positive grid into the stirring cobalt phosphate suspension, and heat to make the water temperature rise to 45°C. After ℃, take out the positive grid and put it in an environment with a relative humidity of 70% and a temperature of 50 ℃ for 3 hours, then put the positive grid in an environment with a relative humidity of 30% and a temperature of 50 ℃ for 8 hours, and finally The positive electrode grid is placed in an environment with a relative humidity of 30% for 2 hours, and the temperature is lowered to room temperature to obtain a treated positive electrode grid.

Mix and stir 1T of positive lead powder and 0.8Kg of fiber, then add 115Kg of pure water, and then add 82Kg of sulfuric acid with a specific gravity of 1.40g/mL to make a paste, and the positive lead paste with a specific gravity of 4.32g/cm3 can be obtained. The positive electrode lead paste is coated on the treated positive electrode grid, and the positive electrode green plate is obtained after acid dipping, surface drying, curing, drying and slice grinding.

Mix 1T of negative lead powder, 8Kg of barium sulfate, 1Kg of lignin, 2Kg of acetylene black and 0.7Kg of fiber, then add 113Kg of pure water, and then add 76Kg of sulfuric acid with a specific gravity of 1.40g/mL to make a paste, and the apparent specific gravity is 4.42. g/cm3 negative lead paste. The negative electrode lead paste is coated on the cast negative grid, and the negative electrode green plate is obtained after acid leaching, surface drying, curing, drying and slice grinding.

6-GF-300 long-life lead-acid battery for floating charge is prepared by wrapping the prepared positive electrode green plate and negative electrode green plate, assembling, adding acid, charging, and grouping.

Three above-mentioned lead-acid batteries were connected in series for 10-hour rate capacity detection. The results are shown in Table 1. After the above-mentioned lead-acid battery is fully charged, it is continuously charged at a constant voltage of 6.75V for 30 days at a temperature of 60±2°C. 5.25V, calculate the discharge capacity of the battery, the above is regarded as a cycle, when the discharge capacity of the battery is lower than 80% of the rated capacity, the battery is dissected at the end of the cycle test, the results are shown in Table 2, the last cycle is not included in the life of the battery cycle.

Example 3

The positive alloy lead is made into a lead tape with a thickness of 2.2mm, and the 6-FM-38 positive grid with a size of 150mm×122mm is made after punching the net, and then knurled with a size of 0.5×0.5mm and a depth of 0.10mm deal with.

In terms of mass percentage, mix 100 parts of pure water and 5 parts of cobalt phosphate, heat to raise the temperature of the suspension to 50 °C, put the positive grid into the stirring cobalt phosphate suspension, and heat to make the water temperature rise to 50 °C. After ℃, take out the positive grid and put it in an environment with a relative humidity of 75% and a temperature of 55 ℃ for 5 hours, and then put the positive grid in an environment with a relative humidity of 35% and a temperature of 55 ℃ for 5 hours, and finally The positive electrode grid was placed in an environment with a relative humidity of 35% for 2 hours, and the temperature was lowered to room temperature to obtain a treated positive electrode grid.

Mix 1T of positive lead powder with 0.9Kg of fiber, then add 115Kg of pure water, and then add 82Kg of sulfuric acid with a specific gravity of 1.40g/mL to make a paste, and the positive lead paste with a specific gravity of 4.30g/cm3 can be obtained. The positive electrode lead paste is coated on the treated positive electrode grid, and the positive electrode green plate is obtained after acid dipping, surface drying, curing, drying and slice grinding.

Mix and stir 1T of negative lead powder, 9Kg of barium sulfate, 2Kg of lignin, 3Kg of acetylene black and 0.8Kg of fiber, then add 113Kg of pure water, and then add 81Kg of sulfuric acid with a specific gravity of 1.40g/mL to make a paste, and the specific gravity is 4.41g /cm3 of negative lead paste. The negative electrode lead paste is coated on the cast negative grid, and the negative electrode green plate is obtained after acid leaching, surface drying, curing, drying and slice grinding.

The prepared positive electrode green plate and negative electrode green plate are packaged, assembled, acidified, charged, assembled and arranged to obtain 6-MF-38 long-life lead-acid battery for floating charge.

Take one of the above-mentioned lead-acid batteries for 10-hour rate capacity testing, and the results are shown in Table 1. After the above-mentioned lead-acid battery is fully charged, it is continuously charged at a constant voltage of 13.80V for 30 days at a temperature of 60±2°C. After taking out the lead-acid battery, it is left for 24h at a temperature of 25±2°C, and then discharged at a current of 3.8A. To 10.50V, calculate the discharge capacity of the battery. The above is a test cycle. When the battery discharge capacity is lower than 80% of the rated capacity, the battery is dissected at the end of the cycle test. The results are shown in Table 2. The last cycle is not included in the battery life cycle.

Comparative Example 1

Mix and stir 1T of positive lead powder and 1Kg of fiber, then add 115Kg of pure water, and then add 92Kg of sulfuric acid with a specific gravity of 1.40g/mL to make a paste, depending on the positive lead paste with a specific gravity of 4.30g/cm3. The 6-GF-100 positive electrode green plate is prepared by coating the positive electrode lead paste on the cast positive electrode grid, leaching acid, surface drying, curing, drying, and slicing polishing.

Mix and stir 1T of negative lead powder, 10Kg of barium sulfate, 3Kg of lignin, 4Kg of acetylene black and 1Kg of fiber, then add 113Kg of pure water, then add 86Kg of sulfuric acid with a specific gravity of 1.40g/mL to mix the paste, and the specific gravity is 4.40g/mL. cm3 negative lead paste. The negative electrode lead paste is coated on the casted 6-GF-100 negative electrode grid, and the negative electrode plate is obtained after acid leaching, surface drying, curing, drying and slice grinding.

6-GF-100 lead-acid battery is prepared by wrapping, assembling, adding acid, charging, and arranging the prepared positive electrode plate and negative electrode plate.

Take one of the above-mentioned lead-acid batteries for 10-hour rate capacity testing, and the results are shown in Table 1. After the lead-acid battery is fully charged, it is continuously charged at 13.80V at 60±2℃ for 30 days. After taking out the battery, let it stand at 25±2℃ for 24h, and then discharge it to 10.50V at a current of 10A. Calculate The discharge capacity of the battery. The above is a test cycle. When the battery discharge capacity is lower than 80% of the rated capacity, the battery is dissected at the end of the cycle test. The results are shown in Table 2. The last cycle is not included in the battery life cycle.

Comparative Example 2

Mix and stir 1T of positive lead powder and 0.8Kg of fiber, add 115Kg of pure water, and then add 82Kg of sulfuric acid with a specific gravity of 1.40g/mL to make a paste to obtain a positive lead paste with a specific gravity of 4.32g/cm3. The 6-GF-100 positive electrode green plate is prepared by coating the positive electrode lead paste on the cast positive electrode grid, leaching acid, surface drying, curing, drying, and slicing polishing.

Mix and stir 1T of negative lead powder, 8Kg of barium sulfate, 1Kg of lignin, 2Kg of acetylene black and 0.7Kg of fiber, then add 113Kg of pure water, and then add 76Kg of sulfuric acid with a specific gravity of 1.40g/mL to make a paste, and the apparent specific gravity is 4.42. g/cm3 negative lead paste. The negative electrode lead paste is coated on the casted 6-GF-300 negative electrode grid, and the negative electrode plate is obtained after acid leaching, surface drying, curing, drying and slice grinding.

6-GF-300 lead-acid battery is prepared by wrapping, assembling, adding acid, charging, and arranging the prepared positive electrode plate and negative electrode plate.

Three above-mentioned lead-acid batteries were connected in series for 10-hour rate capacity detection. The results are shown in Table 1. After the lead-acid battery is fully charged, it is continuously charged at 6.75V at 60±2℃ for 30 days. After taking out the battery, let it stand at 25±2℃ for 24h, and then discharge it to 5.25V at a current of 30A. Calculate The discharge capacity of the battery. The above is a test cycle. When the battery discharge capacity is lower than 80% of the rated capacity, the battery is dissected at the end of the cycle test. The results are shown in Table 2. The last cycle is not included in the battery life cycle.

Comparative Example 3

Mix and stir 1T of positive lead powder and 0.9Kg of fiber, then add 115Kg of pure water, and then add 92Kg of sulfuric acid with a specific gravity of 1.40g/mL to make a paste to obtain a positive lead paste with a specific gravity of 4.30g/cm3. The 6-MF-38 positive electrode green plate is prepared by coating the positive electrode lead paste on the positive electrode grid made by casting, and after acid leaching, surface drying, curing, drying, and slice grinding.

Mix and stir 1T of negative lead powder, 9Kg of barium sulfate, 2Kg of lignin, 3Kg of acetylene black and 0.8Kg of fiber, then add 113Kg of pure water, and then add 81Kg of sulfuric acid with a specific gravity of 1.40g/mL to mix the paste, and the specific specific gravity is 4.41. g/cm3 negative lead paste. The negative electrode lead paste is coated on the casted 6-MF-38 negative electrode grid, and the negative electrode plate is obtained after acid leaching, surface drying, curing, drying and slice grinding.

A 6-MF-38 lead-acid battery is prepared by wrapping, assembling, adding acid, charging, and arranging the prepared positive electrode plate and negative electrode plate.

Take one of the above-mentioned lead-acid batteries for 10-hour rate capacity testing, and the results are shown in Table 1. After the lead-acid battery is fully charged, it is continuously charged at 13.80V at 60±2℃ for 30 days. After taking out the battery, it is allowed to stand at 25±2℃ for 24h, and then discharged to 10.50V with a current of 3.8A. Calculate the discharge capacity of the battery. The above is a test cycle. When the battery discharge capacity is lower than 80% of the rated capacity, the battery is dissected at the end of the cycle test. The results are shown in Table 2. The last cycle is not included in the battery life cycle.

Comparative Example 4

In terms of mass percentage, 100 parts of pure water and 5 parts of cobalt phosphate were mixed, heated to raise the temperature of the solution to 55°C, and the stirring was stopped until the cobalt phosphate particles were precipitated to obtain a saturated aqueous solution of cobalt phosphate, and the undissolved part was precipitated and removed, The positive grid was placed in the cobalt phosphate aqueous solution, and heated to bring the water temperature back to 55°C. Take out the positive grid and put it in an environment with a relative humidity of 80% and a temperature of 60 °C for 4 hours, then put the positive grid in an environment with a relative humidity of 40% and a temperature of 60 °C for 6.5 hours, and finally put the positive electrode The grid is placed in an environment with a relative humidity of 40% for 2 hours, and the temperature is lowered to room temperature to obtain a treated positive grid.

Mix and stir 1T of positive lead powder and 1Kg of fiber, then add 115Kg of pure water, and then add 92Kg of sulfuric acid with a specific gravity of 1.40g/mL to make a paste, depending on the positive lead paste with a specific gravity of 4.30g/cm3. The positive electrode lead paste is coated on the treated positive electrode grid, and the positive electrode green plate is obtained after acid dipping, surface drying, curing, drying and slice grinding.

Table 1 Lead-acid battery for 10-hour rate capacity

As can be seen from Table 1, the 10-hour rate capacity of the lead storage battery prepared by the method in the present application is no different from that of the control group.

Table 2 The capacity inspection discharge cycle and effective cycle number of lead-acid battery

As can be seen from Table 2, the positive electrode grid after soaking and aging in the cobalt phosphate suspension in this application is more corrosion-resistant, and the corrosion resistance of the positive grid after soaking in the cobalt phosphate aqueous solution is slightly stronger than that of the non-immersed positive electrode plate grid; the positive electrode grid is soaked in cobalt phosphate suspension for aging, and the bonding force with the active material is enhanced, and the discharge cycle period of the lead battery prepared by using the positive grid in the solution of the present application is increased by more than 33.3%.

Those skilled in the art can understand that the accompanying drawing is only a schematic diagram of a preferred implementation scenario, and the modules or processes in the accompanying drawing are not necessarily necessary for implementing the embodiments of the present application.

Those skilled in the art can understand that the modules in the device in the implementation scenario may be distributed in the device in the implementation scenario according to the description of the implementation scenario, or may be located in one or more devices different from the implementation scenario with corresponding changes. The modules of the above implementation scenarios may be combined into one module, or may be further split into multiple sub-modules.

The above disclosures are only specific implementation scenarios of the embodiments of the present application, however, the embodiments of the present application are not limited thereto, and any changes that can be conceived by those skilled in the art should fall within the scope of service limitations of the embodiments of the present application.

Claims

A method for preparing a positive plate, comprising the following steps:

(1) Preparation of positive grid;

(2) Immersion of the positive grid,

According to the mass ratio, every 100 parts of pure water and 3 to 5 parts of cobalt phosphate are prepared into a cobalt phosphate suspension, and the positive grid is placed in the cobalt phosphate suspension to soak;

(3) Drying and cooling of the positive grid,

The immersed positive grid is first kept for 3h to 5h under the conditions of relative humidity of 70% to 80% and temperature of 50 to 60°C, and then placed under the conditions of relative humidity of 30% to 40% and temperature of 50 to 60°C. Under the condition of standing for 5-8 hours, the temperature is finally lowered to room temperature within 2 hours under the condition of relative humidity of 30%-40%;

(4) and paste to prepare positive lead paste;

(5) Coating, apply the positive lead paste to the positive grid.
The method for preparing a positive electrode plate according to claim 1, wherein in step (1), the alloy lead is first melted and then made into a lead strip, and then rolled, punched, and knurled to obtain a positive electrode grid.
The method for preparing a positive electrode plate according to claim 2, wherein the thickness of the lead strip after rolling is 2.2-3.2 mm.
The method for preparing a positive electrode plate according to claim 2, wherein the depth of the knurling is 0.1-0.15 mm.
The method for preparing a positive electrode plate according to claim 1, characterized in that, after heating in step (2) to raise the temperature of the cobalt phosphate suspension to 45-55°C, the positive electrode grid is immersed in the cobalt phosphate suspension again. In the liquid, heating to make the water temperature rise back to 45 ~ 55 ℃.
The method for preparing a positive plate according to claim 1, wherein the plate is coated within 8 hours after the drying and cooling are completed.
The method for preparing a positive plate according to claim 1, wherein the positive lead paste comprises lead powder and fibers accounting for 0.08% to 0.10% of the mass of the lead powder, water accounting for 11.5% of the mass of the lead powder and 8.2% of the mass of the lead powder % to 9.2% sulfuric acid with a specific gravity of 1.40 g/mL.
The method for preparing a positive plate according to claim 7, wherein the process of mixing the positive lead paste is as follows: firstly, the lead powder and the fiber are mixed and stirred, and then water and sulfuric acid are added to carry out the mixing process.
A lead storage battery, characterized in that it comprises a positive electrode plate and a negative electrode plate, and the positive electrode plate adopts the positive electrode plate prepared by any one of the preparation methods of claims 1-8.
The lead storage battery according to claim 9, wherein

The formula of negative lead paste: lead powder, barium sulfate accounting for 0.8%-1% by mass of lead powder, lignin accounting for 0.1%-0.3% by mass of lead powder, acetylene black accounting for 0.2%-0.4% by mass of lead powder, lead powder accounting for 0.2%-0.4% by mass 0.07%-0.1% of the powder mass of fiber, 11.3% of the lead powder mass of water and 7.6% to 8.6% of the lead powder mass of sulfuric acid with a specific gravity of 1.4g/mL;

The preparation process of the negative electrode plate is as follows: the lead powder, barium sulfate, lignin, acetylene black and fiber are mixed and stirred, and then water, sulfuric acid and paste are added to obtain the negative electrode lead paste, and the negative electrode lead paste is coated on both sides of the negative electrode grid. Get the negative plate.