A method for preparing positive lead paste for improving the cycle life of lead-acid batteries

Abstract

The present invention provides a synergist for preparing positive electrode lead paste for lead-acid batteries, an acidic auxiliary liquid for preparing positive electrode lead paste for lead-acid batteries, and a method for preparing positive electrode lead paste for improving the cycle life of lead-acid batteries. The synergist of the present invention helps optimize the microstructure of the positive electrode active material, making the crystal structure more regular and stable; the synergist can significantly improve the reversibility of the electrode reaction and inhibit the occurrence of side reactions; and the components in the synergist cooperate with the conductive carbon material to form a more effective conductive network. The good conductivity reduces the internal resistance of the battery, reduces energy loss during the charge and discharge process, improves the charge and discharge efficiency, and thus extends the cycle life of the battery.

Description

Technical Field

[0001] The invention belongs to the technical field of lead-acid batteries, and particularly relates to a method for preparing positive lead paste for improving the cycle life of lead-acid batteries. Background Art

[0002] As a mature secondary battery technology, lead-acid batteries offer unique advantages such as low manufacturing costs, mature technology, simple maintenance, and high-power discharge capability. Consequently, they are widely used in applications such as automotive starting batteries, backup power supplies, communication base stations, and emergency power supplies. In recent years, with the development of electric vehicles, new energy storage systems, and green energy technologies, lead-acid batteries continue to hold a significant position in certain specific application areas. Furthermore, despite the rise of new energy storage technologies such as lithium-ion batteries, lead-acid batteries maintain a high market competitiveness in large-scale applications due to their high recycling rates and low cost.

[0003] In lead-acid batteries, the positive plate material is one of the key factors that determine battery performance. Positive lead paste is the core raw material in the manufacture of positive plates. Its microstructure, uniformity and adhesion with the current collector directly affect the battery's specific capacity, charge and discharge efficiency, cycle life and high-rate performance.

[0004] Patent application publication number CN119447306A discloses a lead paste additive for positive electrode of lead-acid power battery and its application. The additive consists of tin-antimony compound, 4BS and graphite, wherein the amount of tin-antimony compound added is 0.1% to 0.5% by weight of the lead powder used in the positive electrode of the lead-acid power battery, the amount of 4BS added is 0.5% to 2% by weight of the lead powder used in the positive electrode of the lead-acid power battery, and the amount of graphite added is 0.1% to 0.3% by weight of the lead powder used in the positive electrode of the lead-acid power battery.

[0005] Patent application publication number CN118888757A discloses a method for preparing an additive for the positive electrode of a high-capacity energy storage battery and a modified lead paste. Antimony trioxide is encapsulated using microencapsulation technology to produce a chitosan-sodium alginate-starch microcapsule-encapsulated antimony trioxide additive. The lead paste raw materials include lead powder, 4BS seed crystals, dilute sulfuric acid, deionized water, short fibers, and microcapsulated antimony trioxide. Antimony trioxide is encapsulated using microencapsulation technology to produce a sodium alginate-chitosan-starch microcapsule-encapsulated antimony trioxide additive. This additive can not only reduce the inhibitory effect of antimony trioxide on 4BS synthesis, but also increase the 4BS content in the lead paste, which is beneficial to increasing the porosity of the lead paste and strengthening the skeleton structure of the lead paste, but also avoid the influence of the "antimony-free effect" during the charge and discharge process of the battery through the "slow release" mechanism.

[0006] Although the prior art has disclosed a variety of positive lead paste additives that can improve the charge and discharge efficiency and cycle life of lead-acid batteries, there is still room for improvement in the charge and discharge performance and cycle life of lead-acid batteries. Summary of the Invention

[0007] In order to solve the above-mentioned technical problems existing in the prior art, the present invention provides a synergist for preparing positive electrode lead paste of a lead-acid battery, an acidic auxiliary liquid for preparing positive electrode lead paste of a lead-acid battery, and a method for preparing positive electrode lead paste for improving the cycle life of a lead-acid battery.

[0008] The present invention provides a synergist for preparing positive lead paste for lead-acid batteries, which is prepared by mixing and reacting the following raw materials in parts by weight:

[0009] 5-12 parts of borane dimethylamine complex (CAS: 74-94-2), 6-11 parts of dioctyltin maleate (CAS: 16091-18-2) and 2-4 parts of trimethylamine.

[0010] Preferably, the preparation method of the synergist for preparing the positive lead paste of the lead-acid battery comprises the following steps: 5 to 12 parts of borane dimethylamine complex, 6 to 11 parts of dioctyltin maleate, 2 to 4 parts of trimethylamine and 100 to 150 parts of solvent DMF are stirred at 70 to 80 ° C for 2.5 to 5 hours, and DMF is removed by reduced pressure distillation to obtain the synergist for preparing the positive lead paste of the lead-acid battery.

[0011] Reaction mechanism: The amino-olefin addition reaction of borane dimethylamine complex and dioctyltin maleate begins with a nucleophilic attack. The lone pair of electrons of the nitrogen atom in the borane dimethylamine complex acts as a nucleophile to attack the double-bonded carbon atom of dioctyltin maleate, which has a partial positive charge due to the electron-withdrawing effect of the carbonyl group, forming a new carbon-nitrogen bond and a carbon anion intermediate.

[0012] The present invention also provides an acidic auxiliary liquid for preparing positive lead paste of a lead-acid battery, and the preparation method of the acidic auxiliary liquid comprises the following steps:

[0013] By weight, 1 to 4 parts of the above synergist are added to 10 to 40 parts of a 70% to 90% by weight dilute sulfuric acid solution, and stirred for 60 to 100 minutes to obtain an acidic auxiliary liquid.

[0014] The present invention also provides a method for preparing positive lead paste for improving the cycle life of a lead-acid battery, comprising the following steps:

[0015] (1) Adding solid raw materials and dry mixing:

[0016] The solid raw material includes lead powder and a positive electrode additive, wherein the lead powder is 900 to 1100 parts by mass;

[0017] (2) Pure water addition and wet stirring;

[0018] (3) Addition of acidic auxiliary liquid:

[0019] Pour in 1.5 to 2.5 parts by weight of the acidic auxiliary liquid, stirring and mixing continuously during the addition process;

[0020] (4) Addition of dilute sulfuric acid.

[0021] Preferably, in step (1), the positive electrode additives include: 4-butyl sulfonate, antimony trioxide, polyester staple fiber and conductive carbon material, and the solid raw material adding and dry mixing steps in step (1) include: placing 950-1100 parts by mass of high-purity lead powder in a paste mixer; adding 0.4-0.7 parts by mass of 4-butyl sulfonate, 0.7-1.0 parts by mass of antimony trioxide, 0.9-1.2 parts by mass of polyester staple fiber and 1.4-2.0 parts by mass of conductive carbon material, closing the paste mixer, and dry mixing for 5-8 minutes to uniformly mix the solid raw materials.

[0022] Further preferably, the polyester staple fibers have a length of 2 to 5 mm and a diameter of 15 to 30 μm; and the conductive carbon material is selected from at least one of graphite, graphene, carbon black, and acetylene black.

[0023] Preferably, in step (2), the pure water addition and wet stirring step comprises: slowly pouring in 95 to 110 parts by mass of pure water within 5 to 8 minutes, and continuously stirring during the pouring process; after all the pure water is added, continuing to stir for 5 to 8 minutes to form a preliminary wet mixture; in step (3), pouring in 1.5 to 2.5 parts by mass of the acidic auxiliary liquid within 2 to 4 minutes.

[0024] Preferably, in step (4), the dilute sulfuric acid adding step comprises: slowly pouring in 70 to 90 parts by mass of dilute sulfuric acid within 8 to 15 minutes; during the pouring of the dilute sulfuric acid, controlling the temperature in the paste mixer within the process temperature range; after all the dilute sulfuric acid is added, continuing to stir for 10 to 20 minutes to allow the components to fully react and mix, and finally obtaining the positive electrode lead paste.

[0025] Preferably, the concentration of the dilute sulfuric acid is controlled at 4.8-5.5 mol / L; in step (4), the upper limit of the process temperature range is 22-35 °C.

[0026] The present invention also provides a positive electrode lead paste prepared by adopting the positive electrode lead paste preparation method for improving the cycle life of a lead-acid battery.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) Enhanced conductivity: Synergists play a key role in improving the conductivity of positive electrode lead paste. The components in the synergist work synergistically with the conductive carbon material to form a more effective conductive network. The reaction product of borane dimethylamine complex, dioctyltin maleate, and trimethylamine has a unique electronic structure that can promote the rapid conduction of electrons in the lead paste. Good conductivity reduces the internal resistance of the battery, reduces energy loss during the charge and discharge process, improves the charge and discharge efficiency, and thus extends the cycle life of the battery.

[0029] (2) Optimizing the structure of active materials: Synergists help optimize the microstructure of the positive electrode active material. During the curing and use of the lead paste, synergists participate in the crystallization process of the active material, making the crystal structure more regular and stable. Components such as borane dimethylamine complexes affect the crystallization kinetics of lead compounds, avoiding the formation of overly large or unstable crystals and reducing the shedding and pulverization of active materials due to volume changes during charge and discharge cycles. At the same time, synergists interact with components such as polyester staple fibers to strengthen the skeleton structure of the active material and improve its deformation resistance.

[0030] (3) Improving the reversibility of electrode reactions: Synergists can significantly improve the reversibility of electrode reactions. They can reduce the activation energy of electrode reactions and promote more efficient redox reactions on the electrode surface. During the charging process, synergists adsorb on the electrode surface, providing a favorable reaction environment for the oxidation of lead ions; during the discharge process, they can promote the reduction of lead oxides. In addition, synergists can also inhibit the occurrence of side reactions, such as hydrogen evolution and oxygen evolution, making the electrode reaction more specific and improving the battery's charge and discharge efficiency and cycle stability. DETAILED DESCRIPTION

[0031] Example 1

[0032] Step (1) Raw material addition and dry mixing:

[0033] Place 1000 g of high-purity lead powder (99.9% purity or higher) in a paste mixer. Then, add 0.5 g of 4-butylene sulfonate, 0.8 g of antimony trioxide, 1.0 g of polyester staple fibers (3 mm long and 20 μm in diameter), and 1.6 g of graphite conductive carbon material. After sealing the mixer, dry mix at 60 rpm for 5 minutes to ensure thorough premixing of the solid components.

[0034] Step (2) Pure water addition and wet stirring:

[0035] Over 8 minutes, slowly pour in 100 g of pure water, maintaining a stirring speed of 60 rpm during the pouring process to ensure uniform contact between the pure water and the solid components. After all the pure water has been added, continue stirring at the same speed for 7 minutes to form a preliminary wet mixture.

[0036] Step (3) Addition of acidic auxiliary liquid:

[0037] Preparation of the acidic auxiliary liquid: 2 g of borane dimethylamine complex (CAS: 74-94-2), 8 g of dioctyltin maleate (CAS: 16091-18-2), 3 g of trimethylamine, and 120 g of dimethylformamide were mixed and stirred at 75°C for 4 hours. The DMF was then removed by vacuum distillation to prepare the synergist. 3 g of this synergist was then added to 25 g of 80% by weight dilute sulfuric acid solution and stirred for 75 minutes to obtain the acidic auxiliary liquid.

[0038] After the above steps are completed, 1.5 g of acid auxiliary liquid is slowly poured in within 3 minutes. The stirring speed is maintained at 60 rpm during the addition process to ensure that the acid auxiliary liquid is evenly distributed.

[0039] Step (4) Addition of dilute sulfuric acid and temperature control:

[0040] Over 12 minutes, slowly pour in 80 g of 5.0 mol / L dilute sulfuric acid. Simultaneously, start the cooling water and fan to maintain the temperature inside the paste mixer below 25°C. After all the dilute sulfuric acid has been added, continue stirring at 60 rpm for 15 minutes to allow all components to fully react and mix, ultimately obtaining the positive lead paste.

[0041] Example 2

[0042] Step (1) Raw material addition and dry mixing:

[0043] Place 950 g of high-purity lead powder in a paste mixer. Add 0.4 g of 4-butylene sulfonate, 0.7 g of antimony trioxide, 0.9 g of polyester staple fibers (2 mm long and 15 μm in diameter), and 1.4 g of graphene conductive carbon material in that order. After sealing, dry mix at 70 rpm for 6 minutes.

[0044] Step (2) Pure water addition and wet stirring:

[0045] Over 7 minutes, slowly pour in 110 g of pure water while maintaining a stirring speed of 70 rpm. After the pure water is added, continue stirring for 8 minutes.

[0046] Step (3) Addition of acidic auxiliary liquid:

[0047] Preparation of an acidic auxiliary liquid: 10 g of borane dimethylamine complex, 11 g of dioctyltin maleate, 4 g of trimethylamine, and 150 g of dimethylformamide were stirred at 80°C for 3 hours. The DMF was removed by vacuum distillation to prepare a synergist. Subsequently, 1 g of this synergist was dissolved in 30 g of 75% by mass dilute sulfuric acid and stirred for 60 minutes to prepare an acidic auxiliary liquid.

[0048] After the above steps were completed, 2.0 g of acid auxiliary liquid was slowly poured in over 4 minutes, maintaining a stirring speed of 70 rpm.

[0049] Step (4) Addition of dilute sulfuric acid and temperature control:

[0050] Over 10 minutes, slowly pour in 75 g of 4.8 mol / L dilute sulfuric acid. Simultaneously, activate the cooling system to maintain the temperature inside the paste mixer below 30°C. After the addition of the dilute sulfuric acid, continue stirring for 18 minutes to allow the components to fully react and mix, ultimately obtaining the positive lead paste.

[0051] Example 3

[0052] Step (1) Raw material addition and dry mixing:

[0053] Place 1050 g of high-purity lead powder in a paste mixer. Add 0.6 g of 4-butylene sulfonate, 0.9 g of antimony trioxide, 1.1 g of polyester staple fibers (4 mm long and 25 μm in diameter), and 1.9 g of carbon black conductive material in that order. After sealing, dry mix at 50 rpm for 7 minutes.

[0054] Step (2) Pure water addition and wet stirring:

[0055] Over 6 minutes, slowly pour in 98 g of pure water while maintaining a stirring speed of 50 rpm. After the pure water is added, continue stirring for 6 minutes.

[0056] Step (3) Addition of acidic auxiliary liquid:

[0057] Preparation of the acidic auxiliary liquid: Mix 5 g of borane dimethylamine complex, 6 g of dioctyltin maleate, and 2 g of trimethylamine with 100 g of dimethylformamide (DMF). Stir at 70°C for 5 hours. Remove the DMF by vacuum distillation to obtain the synergist. Next, add 4 g of this synergist to 10 g of 90% by mass dilute sulfuric acid solution and stir for 100 minutes to obtain the acidic auxiliary liquid.

[0058] After the above steps are completed, slowly pour in 2.0 g of acid auxiliary liquid within 2 minutes, maintaining a stirring speed of 50 rpm.

[0059] Step (4) Addition of dilute sulfuric acid and temperature control:

[0060] Over 15 minutes, slowly pour in 70 g of 5.2 mol / L dilute sulfuric acid. Simultaneously, activate the cooling system to maintain the temperature inside the paste mixer below 22°C. After the addition of the dilute sulfuric acid, continue stirring for 20 minutes to allow the components to fully react and mix, ultimately obtaining the positive lead paste.

[0061] Example 4

[0062] Step (1) Raw material addition and dry mixing:

[0063] Place 1100 g of high-purity lead powder in a paste mixer. Add 0.7 g of 4-butylene sulfonate, 1.0 g of antimony trioxide, 1.2 g of polyester staple fibers (5 mm long and 30 μm in diameter), and 2.0 g of acetylene black conductive carbon material, in that order. After sealing, dry mix at 80 rpm for 8 minutes.

[0064] Step (2) Pure water addition and wet stirring:

[0065] Over 5 minutes, slowly pour in 95 g of pure water while maintaining a stirring speed of 80 rpm. After the pure water is added, continue stirring for 5 minutes.

[0066] Step (3) Addition of acidic auxiliary liquid:

[0067] Preparation of the acidic auxiliary liquid: 12 g of borane dimethylamine complex, 9 g of dioctyltin maleate, 2.5 g of trimethylamine, and 130 g of dimethylformamide were mixed and stirred at 78°C for 2.5 hours. The DMF was then removed by vacuum distillation to prepare the synergist. Subsequently, 2.5 g of this synergist was dissolved in 40 g of 70% by weight dilute sulfuric acid and stirred for 90 minutes to obtain the desired acidic auxiliary liquid.

[0068] After the above steps are completed, slowly pour in 2.5 g of acid auxiliary liquid within 3 minutes, maintaining a stirring speed of 80 rpm.

[0069] Step (4) Addition of dilute sulfuric acid and temperature control:

[0070] Over 8 minutes, slowly pour in 90 g of 5.5 mol / L dilute sulfuric acid. Simultaneously, activate the cooling system to maintain the temperature inside the paste mixer below 35°C. After the dilute sulfuric acid is added, continue stirring for 10 minutes to allow the components to fully react and mix, ultimately obtaining the positive lead paste.

[0071] Comparative Example 1

[0072] In this example, the acid auxiliary liquid is 70% by mass of dilute sulfuric acid, i.e. no synergist is added. The rest of the process is the same as in Example 1.

[0073] Comparative Example 2

[0074] In this example, no borane dimethylamine complex was added during the preparation of the acidic auxiliary liquid. The remaining process was the same as in Example 1.

[0075] Comparative Example 3

[0076] In this example, no dioctyltin maleate was added during the preparation of the acidic auxiliary liquid. The remaining process was the same as in Example 1.

[0077] Test Example 1

[0078] 1. Initial capacity test

[0079] Test instrument: constant current charge and discharge tester (Arbin test system) is used.

[0080] Sample Preparation: Positive lead pastes were prepared using the present invention and conventional processes, respectively, according to the Examples and Comparative Examples. Positive plates were then prepared using the same process. The positive plates used the same substrate and binder, and all other process parameters were kept consistent, before being assembled into lead-acid batteries.

[0081] Test conditions:

[0082] Charging: Constant current and constant voltage charging mode is adopted, and the charging cut-off voltage is 2.4 V.

[0083] Discharge: constant current discharge is adopted, and the test current density is C / 10 (calculated according to the rated capacity).

[0084] Test indicator: Determine the initial specific capacity of the positive plate (unit: mAh / g). The higher the specific capacity value, the better the utilization rate of the active material.

[0085] 2. Cycle life test

[0086] Test equipment: Utilize a cycle life test system equipped with a temperature control bath to ensure that the test temperature is constant at 25±2°C.

[0087] Sample preparation: The same as that described in the initial specific capacity test.

[0088] Test conditions: Constant current discharge test, depth of discharge controlled at 80% (i.e., cycle life is considered complete when capacity decays to 80% of initial capacity). Charge and discharge cycles are performed at C / 5.

[0089] Test indicators: Record the number of charge and discharge cycles when the positive plate reaches 80% of the initial specific capacity to evaluate the cycle life.

[0090] 3. Plate adhesion test

[0091] Test method: Peel test method.

[0092] Use a standard peel tester (such as an Instron tensile tester) to test the peel force between the lead paste on the positive plate and the current collector at a certain peel speed.

[0093] Test conditions: Peel speed 50 mm / min. Test at least three different areas of each sample, and take the average value as the final test result.

[0094] Test index: expressed as peel force per unit area (N / cm²). The greater the peel force, the better the adhesion between the lead paste and the current collector.

[0095] Table 1: Test results of Examples and Comparative Examples

[0096]

[0097] The test results are shown in Table 1. It can be seen that by adopting the solution of the present invention, the adhesion of the positive electrode lead paste is improved, and the charge and discharge efficiency and cycle life of the lead-acid battery are improved, which proves the advantage of the method of the present invention in improving the overall performance of the lead-acid battery.

Claims

1. A synergist for preparing positive lead paste for lead-acid batteries, characterized in that: The invention is prepared by mixing and reacting the following raw materials in parts by weight: 5 to 12 parts of borane dimethylamine complex, 6 to 11 parts of dioctyltin maleate and 2 to 4 parts of trimethylamine.

2. The synergist for preparing positive lead paste for lead-acid batteries according to claim 1, wherein The preparation method of the synergist for preparing positive lead paste of a lead-acid battery comprises the following steps: 5-12 parts of a borane dimethylamine complex, 6-11 parts of dioctyltin maleate, 2-4 parts of trimethylamine and 100-150 parts of a solvent DMF are stirred at 70-80° C. for 2.5-5 hours, and the DMF is removed by reduced pressure distillation to prepare the synergist for preparing positive lead paste of a lead-acid battery.

3. An acidic auxiliary liquid for preparing positive lead paste for lead-acid batteries, characterized in that: The preparation method of the acidic auxiliary liquid comprises the following steps: By weight, 1 to 4 parts of the synergist according to claim 1 or 2 are added to 10 to 40 parts of a 70% to 90% by weight dilute sulfuric acid solution, and the mixture is stirred to obtain an acidic auxiliary liquid.

4. A method for preparing positive lead paste for improving the cycle life of lead-acid batteries, characterized in that: The following steps are involved: (1) Adding solid raw materials and dry mixing: The solid raw material includes lead powder and a positive electrode additive, wherein the lead powder is 900 to 1100 parts by mass; (2) Pure water addition and wet stirring; (3) Addition of acid auxiliary liquid: Pour 1.5 to 2.5 parts by weight of the acidic auxiliary liquid according to claim 3 into the mixture, stirring and mixing continuously during the addition process; (4) Addition of dilute sulfuric acid.

5. The method for preparing a positive lead paste for improving the cycle life of a lead-acid battery according to claim 4, wherein: In step (1), the positive electrode additives include: 4-butyl sulfonate, antimony trioxide, polyester short fibers and conductive carbon materials. The solid raw material addition and dry mixing steps in step (1) include: 950 to 1100 parts by mass of high-purity lead powder are placed in a paste mixer; 0.4 to 0.7 parts by mass of 4-butyl sulfonate, 0.7 to 1.0 parts by mass of antimony trioxide, 0.9 to 1.2 parts of polyester staple fibers, and 1.4 to 2.0 parts of conductive carbon material are added, the paste mixer is sealed, and dry mixing is performed for 5 to 8 minutes to uniformly mix the solid raw materials.

6. The method for preparing positive lead paste for improving the cycle life of lead-acid batteries according to claim 5, wherein: The polyester staple fibers have a length of 2 to 5 mm and a diameter of 15 to 30 μm; The conductive carbon material is selected from at least one of graphite, graphene, carbon black, and acetylene black.

7. The method for preparing positive lead paste for improving the cycle life of lead-acid batteries according to claim 4, wherein: In step (2), the pure water addition and wet stirring step includes: slowly pouring in 95 to 110 parts by mass of pure water over 5 to 8 minutes, and continuously stirring during the pouring process; after all the pure water is added, continuing to stir for 5 to 8 minutes to form a preliminary wet mixture; In step (3), 1.5 to 2.5 parts by mass of the acidic auxiliary liquid is poured in within 2 to 4 minutes.

8. The method for preparing positive lead paste for improving the cycle life of lead-acid batteries according to claim 4, characterized in that: In step (4), the dilute sulfuric acid adding step comprises: Slowly pour in 70-90 parts by mass of dilute sulfuric acid over 8-15 minutes. During the pouring of dilute sulfuric acid, control the temperature in the paste mixer within the process temperature range. After all the dilute sulfuric acid is added, continue stirring for 10-20 minutes to allow the components to fully react and mix, and finally obtain the positive electrode lead paste.

9. The method for preparing positive lead paste for improving the cycle life of lead-acid batteries according to claim 8, characterized in that: The concentration of the dilute sulfuric acid is controlled at 4.8-5.5 mol / L; In step (4), the upper limit of the process temperature range is 22-35 °C.

10. A positive electrode lead paste prepared by the method for preparing a positive electrode lead paste for improving the cycle life of a lead-acid battery according to any one of claims 4 to 9.

Images