Lead-acid battery and acid circulation equalization formation charging method thereof

Abstract

This invention belongs to the field of lead-acid battery technology, specifically relating to lead-acid batteries and their acid cycle equalization formation and charging method. It includes: firstly, preparing positive and negative electrode plates, wherein single-walled carbon nanotubes are added during the preparation of the negative electrode lead paste, which is then cured and dried to obtain the negative electrode plate; the positive electrode lead paste is diluted and slurryed, then injected into a pipe through an extrusion process, and cured and dried in sections to obtain the positive electrode plate, which is then assembled into a battery to be formed. The battery is connected to an acid cycle system via an equalization connector equipped with an air agitator extending to the bottom of the battery. After electrolyte is filled, the acid cycle system and circulation pump are started, causing the electrolyte to circulate vertically, while current is applied for formation. Pulse charging is used in the early stages of formation. By constructing an acid cycle equalization formation system through an equalization connector equipped with an air agitator, and combining this with early pulse charging to improve formation efficiency, along with the electrode plate modification scheme of adding single-walled carbon nanotubes to the negative electrode and introducing 4BS to the positive electrode, comprehensive optimization of battery performance is achieved.

Description

Technical Field

[0001] This invention belongs to the field of lead-acid battery technology, specifically relating to lead-acid batteries and their acid cycle equalization and charging methods. Background Technology

[0002] Lead-acid batteries, as a power source, have wide applications in many fields. Currently, the formation methods for lead-acid batteries are mainly divided into two categories: internal formation and acid cycle formation. Internal formation involves filling the battery with electrolyte, allowing it to stand, then connecting it in series before charging it with a charger. However, during this process, the electrolyte is prone to stratification, resulting in inconsistent electrolyte density across the battery, a problem particularly pronounced in tall, thin batteries. Acid cycle formation connects the batteries in series to a charger and simultaneously connects them to an acid cycle system via connectors to achieve dynamic acid circulation during formation. However, traditional connector interfaces are only located at the top of the battery, making it difficult to achieve effective acid circulation in the lower region of tall, thin batteries, ultimately failing to solve the problem of uneven electrolyte density across the battery. From a product performance perspective, inconsistent electrolyte density will directly cause differences in the composition and reaction degree of active materials on the upper and lower plates inside the battery. This will not only reduce the battery's charging and discharging efficiency and capacity consistency, but also shorten the battery's cycle life, seriously affecting the battery's overall performance and reliability.

[0003] Given the shortcomings of the traditional formation methods, developing a lead-acid battery acid cycle equalization formation and charging method that can achieve uniform acid circulation and effectively improve electrolyte stratification is of great significance for improving the product performance and market competitiveness of lead-acid batteries. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a method for equalizing and charging lead-acid batteries during acid cycle formation. In the acid cycle formation process, an equalization connector with air stirring function is used to connect the battery to the acid cycle system to achieve equalization. In the initial stage of formation, pulse charging is used to activate the active materials, providing sufficient reaction time and improving formation efficiency. To improve the composition of the active materials in the positive electrode plate and enhance formation efficiency, a paste-making and pouring process is used for the positive electrode, and 4BS seed crystals are added to the positive electrode formulation as a nucleating agent to improve curing and formation effects, optimize the active material composition, and thus improve battery performance.

[0005] Another object of the present invention is to provide a lead-acid battery with good consistency and large capacity.

[0006] The technical solution adopted in this invention is as follows:

[0007] The aforementioned lead-acid battery acid cycle equalization and charging method includes the following steps:

[0008] (1) Shimadzu lead powder, acetylene black, single-walled carbon nanotubes, sodium lignosulfonate, short fibers, ultrafine barium sulfate, sulfuric acid solution and pure water are mixed to make negative electrode lead paste and adjust its apparent density; the negative electrode lead paste is coated on the grid and cured and dried to obtain negative electrode plate;

[0009] Barton lead powder, red lead powder, tetrabasic lead sulfate (4BS), sulfuric acid solution and pure water are mixed to make positive electrode lead paste and adjust its apparent density; pure water is added to the positive electrode lead paste to dilute it and make positive electrode lead slurry and adjust its apparent density; the positive electrode lead slurry is injected into the pipe through the extrusion process and then cured and dried in stages to obtain the positive electrode plate.

[0010] (2) Assemble the positive and negative electrode plates into a battery to be formed;

[0011] (3) Connect the assembled battery to be formed to the acid circulation system through the equalization connector. The equalization connector is equipped with an air stirring device and a circulation pump that extend into the bottom of the battery to be formed.

[0012] (4) Fill the battery to be formed with electrolyte, start the acid circulation system and circulation pump to make the electrolyte circulate up and down inside the battery to be formed; at the same time, apply charging current to the battery to be formed to form it. The formation process includes: using pulse charging in the early stage of formation, followed by constant current charging, constant current discharging and constant current charging operations in sequence.

[0013] The negative electrode lead paste comprises the following raw materials in parts by weight: 100 parts Shimadzu lead powder, 6-8 parts sulfuric acid solution, 0.1-0.3 parts acetylene black, 0.3-0.8 parts single-walled carbon nanotubes, 0.1-0.3 parts sodium lignosulfonate, 0.1-0.2 parts short fibers, 0.1-0.2 parts ultrafine barium sulfate, and 9-11 parts pure water; wherein the diameter of the single-walled carbon nanotubes is 10-30 nm; the particle size of the ultrafine barium sulfate is 0.3-0.6 μm; the length of the short fibers is 4-6 mm; and the density of the sulfuric acid solution is 1.390-1.410 g / cm³. 3 .

[0014] The positive electrode lead paste comprises the following raw materials in parts by weight: 100 parts Barton lead powder, 20-40 parts red lead powder, 1.5-3.5 parts tetrabasic lead sulfate, 7-9 parts sulfuric acid solution, and 9-11 parts pure water; wherein the particle size of the tetrabasic lead sulfate is 2-5 μm; and the density of the sulfuric acid solution is 1.390-1.410 g / cm³. 3 .

[0015] The preparation method of the negative electrode lead paste includes: adding 40-60 wt.% Shimadzu lead powder to a paste mixer, then adding acetylene black, single-walled carbon nanotubes, sodium lignosulfonate, short fibers, and ultrafine barium sulfate, and finally adding the remaining Shimadzu lead powder. After dry mixing for 5 minutes, pure water is added and stirred for 5 minutes. Then, sulfuric acid solution is added at a rate of 0.43-0.50 kg / min and stirred for 15 minutes. Finally, pure water is added, and the density of the negative electrode lead paste is adjusted to 4.3-4.4 g / cm³. 3 ;

[0016] The preparation method of the positive electrode lead paste includes: adding 40-60 wt.% Barton lead powder to a paste mixer, then adding red lead powder and tetrabasic lead sulfate, and finally adding the remaining Barton lead powder. After dry mixing for 5 minutes, pure water is added and stirred for 5 minutes. Then, sulfuric acid solution is added at a rate of 0.43-0.50 kg / min and stirred for 15 minutes. Finally, pure water is added to adjust the apparent density of the positive electrode lead paste to 4.0-4.2 g / cm³. 3 .

[0017] The preparation method of the positive electrode lead paste includes: adding pure water to the positive electrode lead paste, stirring and diluting, and adjusting the apparent density to 3.3~3.5 g / cm³. 3 A needle penetration of 65~75mm is used to obtain positive electrode lead paste;

[0018] The extrusion process includes: transferring the positive lead paste into a working tank and continuously stirring it at a speed of 50-100 r / min. Using fully automatic extrusion equipment, the paste is injected into the pipe through an extrusion pump at an injection pressure of 0.5-2.0 MPa. After sealing, rinsing, and weighing, it is hung on a drying rack to obtain a wet positive lead plate.

[0019] The curing and drying process of the negative electrode plate includes: coating the negative electrode lead paste onto the grid, drying the surface, controlling the moisture content of the wet negative electrode plate to be 8.6%~9.6%, and then hanging the wet negative electrode plate on a drying rack for curing and drying to obtain the negative electrode plate.

[0020] The segmented curing and drying process of the positive electrode plate includes: sending the drying rack with the wet positive electrode plate into the curing and drying kiln, and sequentially carrying out the following six stages of curing and drying to obtain a positive electrode plate with a moisture content ≤1%:

[0021] Phase 1: Temperature 40~50℃, humidity 80%~90%, air volume 40%~50%, time 3~4 hours;

[0022] Phase 2: Temperature 40~50℃, humidity 90%~95%, air volume 30%~40%, time 6~8h;

[0023] Phase 3: Temperature 50~60℃, humidity 70%~80%, air volume 40%~50%, time 6~8h;

[0024] Stage 4: Temperature 55~60℃, humidity 40%~50%, air volume 60%~70%, time 6~8h;

[0025] Stage 5: Temperature 60~70℃, humidity 20%~30%, air volume 70%~80%, time 11~13h;

[0026] Stage 6: Temperature 60~70℃, humidity 10%~20%, air volume 90%~100%, time 11~13h.

[0027] The equalization connector includes a connector, an air stirring tube, an acid inlet tube, an acid outlet tube, a manifold, and a circulation pump. The connector is connected to the electrolyte filling cap of the battery to be formed; the air stirring tube is connected to the bottom acid inlet of the connector; the acid inlet tube is connected to the external acid inlet of the connector; and the acid outlet tube is connected to the external acid outlet of the connector. The acid inlet tubes of each battery to be formed are connected to the acid inlet pipe of the acid circulation system, and the acid outlet tubes of each battery to be formed are connected to the manifold. The manifold is connected to the circulation pump, and the circulation pump is connected to the acid return pipe of the acid circulation system. The power of the circulation pump is 0.8~2.0kW. The air stirring tube has a diameter of 5~10mm, extends 1~3cm into the bottom of the battery, and has an air flow rate of 0.5~1.0L / min.

[0028] The working principle of the equalization connector is as follows;

[0029] The acid circulation system is activated, and acid flows through the inlet pipe to the inlet pipe of each battery to be formed. It then enters the battery through the external inlet of the connector, while an air agitator acts on the bottom of the battery. Once the battery is full of acid, the circulation pump is activated. Under the pump's suction, the acid flows from the battery through the external outlet of the connector into the outlet pipe. The acid discharged from each battery is collected by a manifold and then pumped back to the return pipe of the acid circulation system, ultimately flowing back into the system. During this process, the acid continuously and dynamically circulates between the battery and the acid circulation system, achieving a uniform distribution of acid throughout the battery.

[0030] The formation process includes the following steps performed in sequence:

[0031] Phase 1: Pulse charging is used, with a pulse current of 0.2~0.5C5A, and an interval of 5 minutes of charging followed by 5 minutes of pausing charging, for a total duration of 2~3 hours;

[0032] Phase 2: Charge at a constant current of 0.1~0.2C5A for 1~2 hours;

[0033] Phase 3: Charge at a constant current of 0.2~0.3C5A for 3~5 hours;

[0034] Stage 4: Discharge at a current of -0.25C5A for 1 hour;

[0035] Stage 5: Charge at a constant current of 0.2~0.3C5A for 3~5 hours;

[0036] Stage 6: Charge at a constant current of 0.1~0.2C5A for 8~10 hours.

[0037] The lead-acid battery is prepared using the lead-acid battery acid cycle equalization and charging method described above.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] (1) The lead-acid battery of the present invention effectively improves the conductivity of the negative electrode active material by adding single-walled carbon nanotubes with a diameter of 10~30nm to the negative electrode, thereby improving the initial capacity of the battery.

[0040] (2) The lead-acid battery of the present invention adopts the paste-making and filling process for the positive electrode, and adds 4BS seed crystals as nucleating agents in the positive electrode formula to improve the solidification and formation effect, optimize the active material composition, and thus improve the overall performance of the battery.

[0041] (3) The lead-acid battery acid cycle equalization formation and charging method of the present invention uses an equalization connector equipped with an air stirring device and a circulation pump to connect the battery to the acid cycle system during formation, thereby achieving the function of equalization formation. This connector can continuously flip the sulfuric acid electrolyte at the bottom of the tall and thin battery upward, so that the battery interior forms a dynamic state of up and down circulation, which solves the problem of inconsistent electrolyte density at the top and bottom of the tall and thin battery, improves the consistency of battery performance, and extends the battery life;

[0042] (4) The lead-acid battery acid cycle equalization formation and charging method of the present invention adopts pulse charging in the early stage of formation. In the early stage of the conversion process between negative lead and lead sulfate, and positive lead dioxide and lead sulfate, an intermittent buffer period is formed, so that the rate of chemical reaction to generate lead sulfate and the rate of electrochemical reaction to convert lead sulfate reach a balanced state, thereby improving the formation efficiency. When combined with the above-mentioned equalization connector, the formation efficiency of the present invention is significantly improved compared with the traditional formation method, and the production cost is reduced. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the structure of the equalization connector described in this invention;

[0044] In the diagram: 1. Connector; 2. Air agitator; 3. Acid inlet pipe; 4. Acid outlet pipe; 5. Manifold; 6. Circulation pump; 7. Battery; 8. Acid inlet pipe; 9. Acid return pipe.

[0045] Figure 2 This is a schematic diagram of the structure of a conventional connector as described in this invention;

[0046] In the diagram: 1. Connector; 3. Acid inlet pipe; 4. Acid outlet pipe; 7. Battery; 8. Acid inlet pipe; 9. Acid return pipe. Detailed Implementation

[0047] The present invention will be further described below with reference to the embodiments, but these embodiments do not limit the implementation of the present invention.

[0048] Unless otherwise specified, the raw materials used in the examples and comparative examples are all commercially available materials, and the process methods used in the examples and comparative examples are all conventional methods in the art.

[0049] The following is a description of some of the raw materials used in the examples and comparative examples:

[0050] The ultrafine barium sulfate has a particle size of 0.6 μm;

[0051] The short fiber has a length of 4 mm.

[0052] The equalization connectors used in the embodiments and comparative examples are as follows: Figure 1 As shown, the system includes a connector 1, an air stirring tube 2, an acid inlet tube 3, an acid outlet tube 4, a manifold 5, and a circulation pump 6. The connector 1 is connected to the electrolyte filling cap of the battery to be formed 7. The air stirring tube 2 is connected to the bottom acid inlet of the connector 1. The acid inlet tube 3 is connected to the external acid inlet of the connector 1. The acid outlet tube 4 is connected to the external acid outlet of the connector 1. The acid inlet tube 3 of each battery to be formed 7 is connected to the acid inlet pipe 8 of the acid circulation system. The acid outlet tube 4 of each battery to be formed 7 is connected to the manifold 5. The manifold 5 is connected to the circulation pump 6. The circulation pump 6 is connected to the acid return pipe 9 of the acid circulation system. The air stirring tube has a diameter of 8 mm, extends 2 cm into the bottom of the battery, and has an air flow rate of 0.8 L / min.

[0053] The conventional connector used in Comparative Example 3, such as Figure 2 As shown, it includes a connector 1, an acid inlet pipe 3, and an acid outlet pipe 4; wherein the connector 1 is connected to the liquid filling cap of the battery to be formed 7, the acid inlet pipe 3 is connected to the external acid inlet of the connector 1, and the acid outlet pipe 4 is connected to the external acid outlet of the connector 1; the acid inlet pipe 3 of each battery to be formed 7 is connected to the acid inlet pipe 8 of the acid circulation system, and the acid outlet pipe 4 of each battery to be formed 7 is connected to the acid return pipe 9.

[0054] Example 1

[0055] The aforementioned lead-acid battery acid cycle equalization and charging method includes the following steps:

[0056] (1) Preparation of negative electrode lead paste: 40 kg of Shimadzu lead powder was added to the paste mixer, followed by 0.1 kg of acetylene black, 0.3 kg of single-walled carbon nanotubes with a diameter of 10 nm, 0.1 kg of sodium lignosulfonate, 0.1 kg of short fibers, and 0.1 kg of ultrafine barium sulfate. Finally, the remaining 60 kg of Shimadzu lead powder was added. After dry mixing for 5 min, 9 kg of pure water was added within 5 min. The mixture was stirred for 5 min, and then a paste with a density of 1.390 g / cm³ was added at a rate of 0.43 kg / min. 3 Add 6 kg of sulfuric acid solution, stir for 15 minutes, and finally add pure water. Adjust the density of the negative electrode lead paste to 4.4 g / cm³. 3 ;

[0057] Preparation of positive electrode lead paste: Add 40 kg of Barton lead powder to a paste mixer, then add 20 kg of red lead powder and 1.5 kg of 4BS with a particle size of 2 μm. Finally, add the remaining 60 kg of Barton lead powder, dry mix for 5 min, then add 9 kg of pure water and stir for 5 min. Then, add a paste with a density of 1.390 g / cm³ at a rate of 0.43 kg / min. 3 9 kg of sulfuric acid solution was added and stirred for 15 minutes. Finally, pure water was added, and the apparent density of the positive electrode lead paste was adjusted to 4.2 g / cm³. 3 .

[0058] Preparation and extrusion of positive electrode lead paste: Add 60 kg of pure water to the positive electrode lead paste, stir for 10 min to dilute, and adjust the apparent density to 3.5 g / cm³. 3 A needle penetration of 65mm was used to obtain positive lead paste. The positive lead paste was then transferred to a working tank, which was continuously stirred at a speed of 50 r / min. A fully automatic extrusion device was used to inject the paste into the pipe through an extrusion pump at an injection pressure of 2.0 MPa. After automatic sealing, rinsing, and weighing, the paste was hung on a drying rack to obtain a wet positive lead plate.

[0059] The curing and drying process of the negative electrode plate: The negative electrode lead paste is coated on the grid according to the weight requirements. After the surface is dried quickly, the moisture content of the wet negative electrode plate is controlled to be 8.6%. Then the wet negative electrode plate is hung on the drying rack for curing and drying to obtain the negative electrode plate.

[0060] The segmented curing and drying process of the positive electrode plate: The drying rack with the wet positive electrode plate is sent into the curing and drying kiln, and the following six stages of curing and drying are carried out in sequence to obtain positive electrode plates with a moisture content ≤1%:

[0061] Stage 1 curing: Temperature 40℃, humidity 80%, air volume 40%, time 4h;

[0062] Second stage curing: temperature 40℃, humidity 90%, air volume 30%, time 8h;

[0063] Stage 3 curing: Temperature 50℃, humidity 70%, air volume 40%, time 8h;

[0064] Stage 4 curing: Temperature 55℃, humidity 40%, air volume 60%, time 8h;

[0065] Stage 5 drying: temperature 60℃, humidity 20%, air volume 70%, time 13h;

[0066] Stage 6 drying: temperature 60℃, humidity 10%, air volume 90%, time 13h.

[0067] (2) Assemble the positive and negative electrode plates into a 2V600Ah forklift-powered unformed battery, and assemble a total of 24 batteries;

[0068] (3) After the assembled cells to be formed are connected in series, they are connected to the acid circulation system through the equalization connector. The equalization connector is equipped with an air stirring pipe and a circulation pump that extend into the bottom of the cells to be formed. The power of the circulation pump is 0.8kW.

[0069] (4) The filling density into the battery to be formed is (1.290±0.005) g / cm³. 3 The sulfuric acid electrolyte is used to start the acid circulation system and circulation pump, so that the electrolyte circulates up and down inside the battery to be formed; at the same time, a charging current is applied to the battery to be formed, and the formation process and parameters are as follows:

[0070] Phase 1: Pulse charging is used with a pulse current of 0.2C5 (120) A, and the interval is 5 minutes of charging followed by 5 minutes of stopping charging, for a total duration of 3 hours;

[0071] Phase 2: Charge at a constant current of 0.1C5 (60) A for 2 hours;

[0072] Phase 3: Charge at a constant current of 0.2C5 (120) A for 5 hours;

[0073] Stage 4: Discharge at a current of -0.25C5 (150) A for 1 hour;

[0074] Stage 5: Charge at a constant current of 0.2C5 (120) A for 5 hours;

[0075] Stage 6: Charge at a constant current of 0.1C5 (60) A for 10 hours.

[0076] Example 2

[0077] The aforementioned lead-acid battery acid cycle equalization and charging method includes the following steps:

[0078] (1) Preparation of negative electrode lead paste: 50 kg of Shimadzu lead powder was added to a paste mixer, followed by 0.2 kg of acetylene black, 0.5 kg of single-walled carbon nanotubes with a diameter of 20 nm, 0.2 kg of sodium lignosulfonate, 0.15 kg of short fibers, and 0.15 kg of ultrafine barium sulfate. Finally, the remaining 50 kg of Shimadzu lead powder was added. After dry mixing for 5 min, 10 kg of pure water was added within 5 min. The mixture was stirred for 5 min, and then a paste with a density of 1.400 g / cm³ was added at a rate of 0.47 kg / min. 3 7 kg of sulfuric acid solution was added and stirred for 15 minutes. Finally, pure water was added, and the density of the negative electrode lead paste was adjusted to 4.35 g / cm³. 3 ;

[0079] Preparation of positive electrode lead paste: Add 50 kg of Barton lead powder to a paste mixer, then add 30 kg of red lead powder and 2.5 kg of 4BS with a particle size of 3 μm. Finally, add the remaining 50 kg of Barton lead powder, dry mix for 5 min, then add 10 kg of pure water and stir for 5 min. Then, add a paste with a density of 1.400 g / cm³ at a rate of 0.47 kg / min. 3 8 kg of sulfuric acid solution was added and stirred for 15 minutes. Finally, pure water was added, and the apparent density of the positive electrode lead paste was adjusted to 4.1 g / cm³. 3 .

[0080] Preparation and extrusion of positive electrode lead paste: Add 70 kg of pure water to the positive electrode lead paste, stir for 10 min to dilute, and adjust the apparent density to 3.4 g / cm³. 3 A needle penetration of 70 mm yields positive lead paste. The positive lead paste is then transferred to a working tank, which is continuously stirred at a mixer speed of 80 r / min. A fully automated extrusion pump is used to inject the paste into the pipe at an injection pressure of 1.2 MPa. After automatic sealing, rinsing, and weighing, the paste is hung on a drying rack to obtain a wet positive lead plate.

[0081] The curing and drying process of the negative electrode plate: The negative electrode lead paste is coated on the grid according to the weight requirements. After the surface is dried quickly, the moisture content of the wet negative electrode plate is controlled to be 9.0%. Then the wet negative electrode plate is hung on the drying rack for curing and drying to obtain the negative electrode plate.

[0082] The segmented curing and drying process of the positive electrode plate: The drying rack with the wet positive electrode plate is sent into the curing and drying kiln, and the following six stages of curing and drying are carried out in sequence to obtain positive electrode plates with a moisture content ≤1%:

[0083] Stage 1 curing: Temperature 45℃, humidity 85%, air volume 45%, time 3.5h;

[0084] Second stage curing: temperature 45℃, humidity 93%, air volume 35%, time 7h;

[0085] Stage 3 curing: Temperature 55℃, humidity 75%, air volume 45%, time 7h;

[0086] Stage 4 curing: Temperature 60℃, humidity 45%, air volume 65%, time 7h;

[0087] Stage 5 drying: temperature 65℃, humidity 25%, air volume 75%, time 12h;

[0088] Stage 6 drying: temperature 65℃, humidity 15%, air volume 95%, time 12h.

[0089] (2) Assemble the positive and negative electrode plates into a 2V600Ah forklift-powered unformed battery, and assemble a total of 24 batteries;

[0090] (3) After the assembled cells to be formed are connected in series, they are connected to the acid circulation system through the equalization connector. The equalization connector is equipped with an air stirring pipe and a circulation pump that extend into the bottom of the cells to be formed. The power of the circulation pump is 1.4kW.

[0091] (4) The filling density into the battery to be formed is (1.290±0.005) g / cm³. 3 The sulfuric acid electrolyte is used to start the acid circulation system and circulation pump, so that the electrolyte circulates up and down inside the battery to be formed; at the same time, a charging current is applied to the battery to be formed, and the formation process and parameters are as follows:

[0092] Phase 1: Pulse charging is used with a pulse current of 0.3C5 (180) A, and the interval is 5 minutes of charging followed by 5 minutes of stopping charging, for a total duration of 2.5 hours;

[0093] Phase 2: Charge at a constant current of 0.15C5 (90) A for 1.5 hours;

[0094] Stage 3: Charge at a constant current of 0.25C5 (150) A for 4 hours;

[0095] Stage 4: Discharge at a current of -0.25C5 (150) A for 1 hour;

[0096] Stage 5: Charge at a constant current of 0.25C5 (150) A for 4 hours;

[0097] Stage 6: Constant current charging at 0.15C5 (90) A for 9 hours.

[0098] Example 3

[0099] The aforementioned lead-acid battery acid cycle equalization and charging method includes the following steps:

[0100] (1) Preparation of negative electrode lead paste: 60 kg of Shimadzu lead powder was added to the paste mixer, followed by 0.3 kg of acetylene black, 0.8 kg of single-walled carbon nanotubes with a diameter of 30 nm, 0.3 kg of sodium lignosulfonate, 0.2 kg of short fibers, and 0.2 kg of ultrafine barium sulfate. Finally, the remaining 40 kg of Shimadzu lead powder was added. After dry mixing for 5 min, 11 kg of pure water was added within 5 min. The mixture was stirred for 5 min, and then added at a rate of 0.50 kg / min with a density of 1.410 g / cm³. 3 8 kg of sulfuric acid solution was added and stirred for 15 minutes. Finally, pure water was added, and the density of the negative electrode lead paste was adjusted to 4.3 g / cm³. 3 ;

[0101] Preparation of positive electrode lead paste: Add 60 kg of Barton lead powder to a paste mixer, then add 40 kg of red lead powder and 3.5 kg of 4BS with a particle size of 5 μm. Finally, add the remaining 40 kg of Barton lead powder, dry mix for 5 min, then add 11 kg of pure water and stir for 5 min. Then, add a paste with a density of 1.410 g / cm³ at a rate of 0.50 kg / min. 3 7 kg of sulfuric acid solution was added and stirred for 15 minutes. Finally, pure water was added, and the apparent density of the positive electrode lead paste was adjusted to 4.0 g / cm³. 3 .

[0102] Preparation and extrusion of positive electrode lead paste: Add 80 kg of pure water to the positive electrode lead paste, stir for 10 min to dilute, and adjust the apparent density to 3.3 g / cm³. 3 A needle penetration of 75 mm yields positive lead paste. The positive lead paste is then transferred to a working tank, which is continuously stirred at a mixer speed of 50 r / min. A fully automated extrusion pump is used to inject the paste into the pipe at an injection pressure of 0.5 MPa. After automatic sealing, rinsing, and weighing, the paste is hung on a drying rack to obtain a wet positive lead plate.

[0103] The curing and drying process of the negative electrode plate: The negative electrode lead paste is coated on the grid according to the weight requirements. After the surface is dried quickly, the moisture content of the wet negative electrode plate is controlled to be 9.6%. Then the wet negative electrode plate is hung on the drying rack for curing and drying to obtain the negative electrode plate.

[0104] The segmented curing and drying process of the positive electrode plate: The drying rack with the wet positive electrode plate is sent into the curing and drying kiln, and the following six stages of curing and drying are carried out in sequence to obtain positive electrode plates with a moisture content ≤1%:

[0105] Stage 1 curing: Temperature 50℃, humidity 90%, air volume 50%, time 3 hours;

[0106] Second stage curing: temperature 50℃, humidity 95%, air volume 40%, time 6h;

[0107] Stage 3 curing: Temperature 60℃, humidity 80%, air volume 50%, time 6 hours;

[0108] Stage 4 curing: Temperature 60℃, humidity 50%, air volume 70%, time 6 hours;

[0109] Stage 5 drying: temperature 70℃, humidity 30%, air volume 80%, time 11h;

[0110] Stage 6 drying: temperature 70℃, humidity 20%, air volume 100%, time 11h.

[0111] (2) Assemble the positive and negative electrode plates into a 2V600Ah forklift-powered unformed battery, and assemble a total of 24 batteries;

[0112] (3) After the assembled cells to be formed are connected in series, they are connected to the acid circulation system through the equalization connector. The equalization connector is equipped with an air stirring pipe and a circulation pump that extend into the bottom of the cells to be formed. The power of the circulation pump is 2.0kW.

[0113] (4) The filling density into the battery to be formed is (1.290±0.005) g / cm³. 3 The sulfuric acid electrolyte is used to start the acid circulation system and circulation pump, so that the electrolyte circulates up and down inside the battery to be formed; at the same time, a charging current is applied to the battery to be formed, and the formation process and parameters are as follows:

[0114] Phase 1: Pulse charging is used, with a pulse current of 0.5C5 (300) A, and the interval is 5 minutes of charging followed by 5 minutes of stopping charging, for a total duration of 2 hours;

[0115] Phase 2: Charge at a constant current of 0.2C5 (120) A for 1 hour;

[0116] Phase 3: Charge at a constant current of 0.3C5 (180) A for 3 hours;

[0117] Stage 4: Discharge at a current of -0.25C5 (150) A for 1 hour;

[0118] Stage 5: Charge at a constant current of 0.3C5 (180) A for 3 hours;

[0119] Stage 6: Charge at a constant current of 0.2C5 (120) A for 8 hours.

[0120] Comparative Example 1

[0121] The difference from Example 3 is that no single-walled carbon nanotubes were added to the negative electrode lead paste; otherwise, it is the same as Example 3.

[0122] Comparative Example 2

[0123] The difference from Example 3 is that the preparation process of the wet positive electrode plate is as follows:

[0124] After premixing 100 kg of Shimadzu lead powder and 20 kg of red lead powder evenly, the mixture was poured into a discharge pipe using a powder filling tool, the bottom was sealed, and a container with a density of 1.100 g / cm³ was placed inside. 3 Soaking in sulfuric acid solution for 2 hours yields wet positive electrode plates.

[0125] This method does not include the preparation of positive electrode lead paste, positive electrode lead slurry, and extrusion process as described in Example 3; otherwise, it is the same as in Example 3.

[0126] Comparative Example 3

[0127] The difference from Example 3 is that, after the assembled battery to be formed is connected in series, it is connected to the acid cycle system through a conventional connector. A schematic diagram of this conventional connector is shown below. Figure 2 As shown.

[0128] Its formation process and parameters are as follows:

[0129] Phase 1: Charge at a constant current of 0.025C5(15)A for 0.5h;

[0130] Phase 2: Charge at a constant current of 0.05C5(30)A for 0.5h;

[0131] Phase 3: Charge at a constant current of 0.1C5 (60) A for 1 hour;

[0132] Stage 4: Charge at a constant current of 0.2C5 (120) A for 7 hours;

[0133] Stage 5: Charge at a constant current of 0.25C5 (150) A for 10 hours;

[0134] Stage 6: Discharge at a current of -0.25C5 (150) A for 0.5 hours;

[0135] Stage 7: Charge at a constant current of 0.25C5 (150) A for 15 hours;

[0136] Stage 8: Charge at a constant current of 0.15C5 (90) A for 8 hours;

[0137] The total time for the formation was 42.5 hours.

[0138] Everything else is the same as in Example 3.

[0139] Using the positive and negative electrode plates formed in Examples 1-3 and Comparative Examples 1-3, 2V 600Ah forklift power lead-acid batteries were assembled respectively. The specific process is as follows:

[0140] 1) The outer shell is made of PP material;

[0141] 2) The partitions are made of PE material;

[0142] 3) The positive grid is produced by die casting of a low-antimony pentagonal alloy. The mass percentage of each component of the alloy is: 2.8% Sb, 0.12% As, 0.15% Sn, 0.01% Cu, with the balance being Pb.

[0143] 4) The negative grid is produced by gravity casting of a low-antimony hexa-element alloy. The mass percentage of each component of the alloy is: 1.8%Sb, 0.12%As, 0.03%Se, 0.09%Sn, 0.035%Cu, with the balance being Pb.

[0144] 5) Battery assembly adopts conventional processes.

[0145] The performance of the assembled lead-acid batteries was tested separately, and the test methods are as follows:

[0146] 120A discharge capacity (Ah): Tested according to GB / T 7403.1-2018;

[0147] The percentage of discharge capacity to rated capacity (%): tested in accordance with GB / T 7403.1-2018;

[0148] 600A discharge (min): Tested according to GB / T 7403.1-2018;

[0149] The test results are shown in Table 1.

[0150] Table 1 Performance Test Results

[0151]

[0152] As can be seen from Table 1, the discharge capacity and high-rate discharge of the lead-acid batteries prepared in Examples 1-3 are significantly higher than those prepared in Comparative Examples 1-3, indicating that the charging method for acid cycle equalization formation of lead-acid batteries described in this invention can significantly improve battery capacity.

Claims

1. A method for equalizing and charging a lead-acid battery during acid cycle, characterized in that, Includes the following steps: (1) Shimadzu lead powder, acetylene black, single-walled carbon nanotubes, sodium lignosulfonate, short fibers, ultrafine barium sulfate, sulfuric acid solution and pure water are mixed to make negative electrode lead paste and adjust its apparent density; the negative electrode lead paste is coated on the grid and cured and dried to obtain negative electrode plate; Barton lead powder, red lead powder, tetrabasic lead sulfate, sulfuric acid solution and pure water are mixed to make positive electrode lead paste and its apparent density is adjusted; pure water is added to the positive electrode lead paste to dilute it and make positive electrode lead slurry and its apparent density is adjusted; the positive electrode lead slurry is injected into the pipe through the extrusion process and then cured and dried in stages to obtain the positive electrode plate. (2) Assemble the positive and negative electrode plates into a battery to be formed; (3) Connect the assembled battery to be formed to the acid circulation system through the equalization connector. The equalization connector is equipped with an air stirring device and a circulation pump that extend into the bottom of the battery to be formed. (4) Fill the battery to be formed with electrolyte, start the acid circulation system and circulation pump to make the electrolyte circulate up and down inside the battery to be formed; at the same time, apply charging current to the battery to be formed to form it. The formation process includes: using pulse charging in the early stage of formation, followed by constant current charging, constant current discharging and constant current charging operations in sequence. The equalization connector includes a connector, an air stirring tube, an acid inlet pipe, an acid outlet pipe, a manifold, and a circulation pump. The connector is connected to the electrolyte filling cap of the battery to be formed; the air stirring tube is connected to the bottom acid inlet of the connector; the acid inlet pipe is connected to the external acid inlet of the connector; and the acid outlet pipe is connected to the external acid outlet of the connector. The acid inlet pipes of each battery to be formed are connected to the acid inlet pipe of the acid circulation system, and the acid outlet pipes of each battery to be formed are connected to the manifold. The manifold is connected to the circulation pump, and the circulation pump is connected to the acid return pipe of the acid circulation system. The power of the circulation pump is 0.8~2.0kW. The formation process includes the following steps performed in sequence: Phase 1: Pulse charging is used, with a pulse current of 0.2~0.5C5A, and an interval of 5 minutes of charging followed by 5 minutes of pausing charging, for a total duration of 2~3 hours; Phase 2: Charge at a constant current of 0.1~0.2C5A for 1~2 hours; Phase 3: Charge at a constant current of 0.2~0.3C5A for 3~5 hours; Stage 4: Discharge at a current of -0.25C5A for 1 hour; Stage 5: Charge at a constant current of 0.2~0.3C5A for 3~5 hours; Stage 6: Charge at a constant current of 0.1~0.2C5A for 8~10 hours.

2. The lead-acid battery acid cycle equalization and charging method according to claim 1, characterized in that, The negative electrode lead paste comprises the following raw materials in parts by weight: 100 parts Shimadzu lead powder, 6-8 parts sulfuric acid solution, 0.1-0.3 parts acetylene black, 0.3-0.8 parts single-walled carbon nanotubes, 0.1-0.3 parts sodium lignosulfonate, 0.1-0.2 parts short fibers, 0.1-0.2 parts ultrafine barium sulfate, and 9-11 parts pure water; wherein the diameter of the single-walled carbon nanotubes is 10-30 nm; the particle size of the ultrafine barium sulfate is 0.3-0.6 μm; the length of the short fibers is 4-6 mm; and the density of the sulfuric acid solution is 1.390-1.410 g / cm³. 3 .

3. The lead-acid battery acid cycle equalization and charging method according to claim 1, characterized in that, The positive electrode lead paste comprises the following raw materials in parts by weight: 100 parts Barton lead powder, 20-40 parts red lead powder, 1.5-3.5 parts tetrabasic lead sulfate, 7-9 parts sulfuric acid solution, and 9-11 parts pure water; wherein the particle size of the tetrabasic lead sulfate is 2-5 μm; and the density of the sulfuric acid solution is 1.390-1.410 g / cm³. 3 .

4. The lead-acid battery acid cycle equalization and charging method according to claim 1, characterized in that, The preparation method of the negative electrode lead paste includes: adding 40-60 wt.% Shimadzu lead powder to a paste mixer, then adding acetylene black, single-walled carbon nanotubes, sodium lignosulfonate, short fibers, and ultrafine barium sulfate, and finally adding the remaining Shimadzu lead powder. After dry mixing, pure water is added and stirred. Then, sulfuric acid solution is added at a rate of 0.43-0.50 kg / min and stirred. Finally, pure water is added to adjust the density of the negative electrode lead paste to 4.3-4.4 g / cm³. 3 ; The preparation method of the positive electrode lead paste includes: adding 40-60 wt.% Barton lead powder to a paste mixer, then adding red lead powder and tetrabasic lead sulfate, and finally adding the remaining Barton lead powder. After dry mixing, pure water is added and stirred. Then, sulfuric acid solution is added at a rate of 0.43-0.50 kg / min while stirring. Finally, pure water is added, and the density of the positive electrode lead paste is adjusted to 4.0-4.2 g / cm³. 3 .

5. The lead-acid battery acid cycle equalization and charging method according to claim 1, characterized in that, The preparation method of the positive electrode lead paste includes: adding pure water to the positive electrode lead paste, stirring and diluting, and adjusting the apparent density to 3.3~3.5 g / cm³. 3 A needle penetration of 65~75mm is used to obtain positive electrode lead paste; The extrusion process includes: transferring the positive lead paste into the working tank and stirring continuously; using an extrusion pump to inject the paste into the drain pipe at an injection pressure of 0.5~2.0MPa; after sealing the bottom, rinsing, and weighing, hanging it on a drying rack to obtain a wet positive lead plate.

6. The lead-acid battery acid cycle equalization and charging method according to claim 1, characterized in that, The curing and drying process of the negative electrode plate includes: coating the negative electrode lead paste onto the grid, drying the surface, controlling the moisture content of the wet negative electrode plate to be 8.6%~9.6%, and then hanging the wet negative electrode plate on a drying rack for curing and drying to obtain the negative electrode plate.

7. The lead-acid battery acid cycle equalization and charging method according to claim 1, characterized in that, The segmented curing and drying process of the positive electrode plate includes: sending the drying rack with the wet positive electrode plate into the curing and drying kiln, and sequentially carrying out the following six stages of curing and drying to obtain a positive electrode plate with a moisture content ≤1%: Phase 1: Temperature 40~50℃, humidity 80%~90%, air volume 40%~50%, time 3~4 hours; Phase 2: Temperature 40~50℃, humidity 90%~95%, air volume 30%~40%, time 6~8h; Phase 3: Temperature 50~60℃, humidity 70%~80%, air volume 40%~50%, time 6~8h; Stage 4: Temperature 55~60℃, humidity 40%~50%, air volume 60%~70%, time 6~8h; Stage 5: Temperature 60~70℃, humidity 20%~30%, air volume 70%~80%, time 11~13h; Stage 6: Temperature 60~70℃, humidity 10%~20%, air volume 90%~100%, time 11~13h.

8. A lead-acid battery, characterized in that, It is prepared by the lead-acid battery acid cycle equalization and charging method according to any one of claims 1 to 7.

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