Preparation method of positive lead paste for prolonging cycle life of lead storage battery

Abstract

The invention provides a synergist for preparing positive lead paste of a lead storage battery, an acidic auxiliary liquid for preparing the positive lead paste of the lead storage battery, and a preparation method of the positive lead paste for prolonging the cycle life of the lead storage battery. The synergist provided by the invention is helpful for optimizing the microstructure of the positive electrode active material, so that the crystal structure is more regular and stable; the synergist can significantly improve the reversibility of the electrode reaction and inhibit the occurrence of side reactions; in addition, through the cooperation of the components in the synergist and the conductive carbon material, a more effective conductive network is formed, the internal resistance of the battery is reduced due to good conductivity, the energy loss in the charging and discharging process is reduced, the charging and discharging efficiency is improved, and the cycle life of the battery is further prolonged.

Description

Technical Field

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

[0002] As a mature secondary battery technology, lead-acid batteries have the unique advantages of low manufacturing cost, mature technology, simple maintenance, and high-power discharge, etc., and are thus widely used in fields 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 energy storage systems, and green energy technologies, lead-acid batteries still play an important role in some specific application fields. At the same time, although new energy storage technologies such as lithium-ion batteries are gradually emerging, lead-acid batteries still have high market competitiveness in large-scale applications due to their high recovery rate and low-cost advantages.

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

[0004] The patent application with the publication number CN119447306A discloses a positive lead paste additive for lead-acid power batteries and its application. The additive is composed of a tin-antimony compound, 4BS, and graphite. Among them, the addition amount of the tin-antimony compound is 0.1% - 0.5% of the weight of the lead powder used in the positive electrode of the lead-acid power battery, the addition amount of 4BS is 0.5% - 2% of the weight of the lead powder used in the positive electrode of the lead-acid power battery, and the addition amount of graphite is 0.1% - 0.3% of the weight of the lead powder used in the positive electrode of the lead-acid power battery.

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

[0006] Although various positive electrode lead paste additives have been disclosed in the prior art to improve the charge and discharge efficiency and cycle service life of lead-acid batteries, there is still room for improvement in the charge and discharge performance and cycle service life of lead-acid batteries. Summary of the Invention

[0007] To solve the above 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 electrode lead paste of a lead-acid battery, which is prepared by mixing and reacting raw materials including the following parts by weight: 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.

[0009] Preferably, the preparation method of the synergist for preparing positive electrode lead paste of the lead-acid battery includes the following steps: mixing 5 - 12 parts of borane dimethylamine complex, 6 - 11 parts of dioctyltin maleate, 2 - 4 parts of trimethylamine with 100 - 150 parts of solvent DMF, stirring at 70 - 80 °C for 2.5 - 5 h, and removing DMF by vacuum distillation to obtain the synergist for preparing positive electrode lead paste of the lead-acid battery.

[0010] Reaction mechanism: The amino-olefin addition reaction of borane dimethylamine complex and dioctyltin maleate starts with nucleophilic attack. The lone pair of electrons on the nitrogen atom in borane dimethylamine complex acts as a nucleophile, attacking the double bond carbon atom of dioctyltin maleate with partial positive charge due to the electron-withdrawing effect of the carbonyl group, forming a new carbon-nitrogen bond and a carbanion intermediate.

[0011] The present invention also provides an acidic auxiliary liquid for preparing positive electrode lead paste of a lead-acid battery. The preparation method of the acidic auxiliary liquid includes the following steps: By weight, adding 1 - 4 parts of the above synergist to 10 - 40 parts of a dilute sulfuric acid solution with a mass percentage of 70% - 90%, and stirring and mixing for 60 - 100 minutes to obtain the acidic auxiliary liquid.

[0012] The present invention also provides a method for preparing positive electrode lead paste for improving the cycle life of a lead-acid battery, including the following steps: (1) Solid raw material feeding and dry mixing: The solid raw materials include lead powder and positive electrode additives, and the lead powder is 900 - 1100 parts by mass; (2) Pure water addition and wet stirring; (3) Addition of acidic auxiliary liquid: Pour in 1.5 to 2.5 parts by mass of the acidic auxiliary liquid, and continuously stir and mix evenly during the addition process; (4)Dilute sulfuric acid addition.

[0013] Preferably, in step (1), the positive electrode additive includes: 4-butyl sulfonate, antimony trioxide, polyester staple fiber, and conductive carbon material. The solid raw material feeding and dry mixing steps in step (1) include: placing 950 to 1100 parts by mass of high-purity lead powder in a paste mixer; adding 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 fiber, and 1.4 to 2.0 parts of conductive carbon material. After closing the paste mixer, dry mix for 5 to 8 minutes to make the solid raw materials mix evenly.

[0014] Further preferably, the length of the polyester staple fiber is 2 to 5 mm and the diameter is 15 to 30 μm; the conductive carbon material is selected from at least one of graphite, graphene, carbon black, and acetylene black.

[0015] Preferably, in step (2), the pure water addition and wet stirring steps include: 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, continue to stir for 5 to 8 minutes to form a preliminary wet mixture; in step (3), pour in 1.5 to 2.5 parts by mass of the acidic auxiliary liquid within 2 to 4 minutes.

[0016] Preferably, in step (4), the dilute sulfuric acid addition step includes: 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, control the temperature in the paste mixer within the process temperature range; after all the dilute sulfuric acid is added, continue to stir for 10 to 20 minutes to make each component fully react and mix, and finally obtain the positive electrode lead paste.

[0017] Preferably, the concentration of the dilute sulfuric acid is controlled at 4.8 to 5.5 mol / L; in step (4), the upper limit of the process temperature range is 22 - 35 °C.

[0018] The present invention also provides a positive electrode lead paste prepared by using the above positive electrode lead paste preparation method for improving the cycle life of a lead-acid battery.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1)Enhanced conductivity: The synergist plays a key role in improving the conductivity of the positive electrode lead paste. The components in the synergist cooperate 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, which can promote the rapid conduction of electrons in the lead paste. Good conductivity reduces the internal resistance of the battery, reduces the energy loss during charge and discharge, improves the charge and discharge efficiency, and thus extends the cycle life of the battery.

[0020] (2) Optimize the structure of the active material: The synergist helps to optimize the microstructure of the positive active material. During the curing and use of the lead paste, the synergist participates in the crystallization process of the active material, making the crystal structure more regular and stable. Components such as borane dimethylamine complex affect the crystallization kinetics of lead compounds, avoiding the formation of overly large or unstable crystals, and reducing the shedding and pulverization of the active material caused by volume changes during charge and discharge cycles. At the same time, the synergist interacts with components such as polyester staple fibers to strengthen the framework structure of the active material and improve its anti-deformation ability.

[0021] (3) Improve the reversibility of the electrode reaction: The synergist can significantly improve the reversibility of the electrode reaction. It can reduce the activation energy of the electrode reaction and promote the more efficient progress of the redox reaction on the electrode surface. During the charging process, the synergist adsorbs on the electrode surface, providing a favorable reaction environment for the oxidation of lead ions; during the discharging process, it can promote the reduction of lead oxide. In addition, the synergist can also inhibit the occurrence of side reactions, such as hydrogen evolution and oxygen evolution reactions, making the electrode reaction more specific, and improving the charge-discharge efficiency and cycle stability of the battery. Specific implementation method

[0022] Example 1 Step (1) Raw material addition and dry mixing: Place 1000 g of high-purity lead powder (purity not less than 99.9%) in a paste mixer. Subsequently, add 0.5 g of 4-butylsulfonate, 0.8 g of antimony trioxide, 1.0 g of polyester staple fiber with a length of 3 mm and a diameter of 20 μm, and 1.6 g of graphite conductive carbon material in sequence. After closing the paste mixer, dry mix at a speed of 60 rpm for 5 minutes to ensure that the solid components are fully pre-mixed.

[0023] Step (2) Pure water addition and wet stirring: Slowly pour in 100 g of pure water within 8 minutes, and maintain 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 is added, continue to stir at the same speed for 7 minutes to form a preliminary wet mixture.

[0024] Step (3) Addition of acidic auxiliary liquid: Preparation of acidic auxiliary liquid: Mix 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 DMF, stir at 75 °C for 4 hours, and then perform vacuum distillation to remove DMF to obtain a synergist. Then add 3 g of this synergist to 25 g of a dilute sulfuric acid solution with a mass percentage of 80%, and stir and mix for 75 minutes to obtain an acidic auxiliary liquid.

[0025] After the above steps are completed, slowly pour in 1.5 g of acidic auxiliary solution within 3 minutes, and maintain a stirring speed of 60 rpm during the addition process to ensure uniform distribution of the acidic auxiliary solution.

[0026] Step (4) Dilute sulfuric acid addition and temperature control: Within 12 minutes, slowly pour in 80 g of dilute sulfuric acid with a concentration of 5.0 mol / L. At the same time, start the cooling circulation cooling water machine and the cooling fan to keep the temperature in the paste mixer below 25 °C. After all the dilute sulfuric acid is added, continue to stir for 15 minutes under the stirring condition of 60 rpm to allow the components to react and mix fully, and finally obtain the positive electrode lead paste.

[0027] Example 2 Step (1) Raw material addition and dry mixing: Place 950 g of high-purity lead powder in the paste mixer. Sequentially add 0.4 g of 4-butylsulfonate, 0.7 g of antimony trioxide, 0.9 g of polyester short fibers with a length of 2 mm and a diameter of 15 μm, and 1.4 g of graphene conductive carbon material. After closing, dry mix at a rotation speed of 70 rpm for 6 minutes.

[0028] Step (2) Pure water addition and wet stirring: Within 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 to stir for 8 minutes.

[0029] Step (3) Addition of acidic auxiliary solution: Preparation of acidic auxiliary solution: Take 10 g of borane dimethylamine complex, 11 g of dioctyltin maleate, 4 g of trimethylamine, and 150 g of DMF, stir at 80 °C for 3 hours, and remove DMF by vacuum distillation to obtain a synergist. Subsequently, dissolve 1 g of this synergist in 30 g of dilute sulfuric acid with a mass percentage of 75%, and stir and mix for 60 minutes to prepare the acidic auxiliary solution.

[0030] After the above steps are completed, slowly pour in 2.0 g of acidic auxiliary solution within 4 minutes while maintaining a stirring speed of 70 rpm.

[0031] Step (4) Dilute sulfuric acid addition and temperature control: Within 10 minutes, slowly pour in 75 g of dilute sulfuric acid with a concentration of 4.8 mol / L. At the same time, start the cooling system to keep the temperature in the paste mixer below 30 °C. After the dilute sulfuric acid is added, continue to stir for 18 minutes to allow the components to react and mix fully, and finally obtain the positive electrode lead paste.

[0032] Example 3

[0033] Step (1) Raw material addition and dry mixing: Place 1050 g of high-purity lead powder into a paste mixer. Sequentially add 0.6 g of 4-butylsulfonate, 0.9 g of antimony trioxide, 1.1 g of polyester short fibers with a length of 4 mm and a diameter of 25 μm, and 1.9 g of carbon black conductive carbon material. After sealing, dry mix at a speed of 50 rpm for 7 minutes.

[0034] Step (2) Pure water addition and wet stirring: Slowly pour in 98 g of pure water within 6 minutes while maintaining a stirring speed of 50 rpm. After the pure water is added, continue stirring for 6 minutes.

[0035] Step (3) Addition of acidic auxiliary liquid: Preparation of acidic auxiliary liquid: Mix 5 g of borane dimethylamine complex, 6 g of dioctyltin maleate, 2 g of trimethylamine with 100 g of DMF, stir at 70 °C for 5 hours, and remove DMF by vacuum distillation to obtain a synergist. Then, add 4 g of this synergist to 10 g of a dilute sulfuric acid solution with a mass percentage of 90%, stir and mix for 100 minutes to prepare the acidic auxiliary liquid.

[0036] After the above steps are completed, slowly pour in 2.0 g of acidic auxiliary liquid within 2 minutes while maintaining a stirring speed of 50 rpm.

[0037] Step (4) Dilute sulfuric acid addition and temperature control: Slowly pour in 70 g of dilute sulfuric acid with a concentration of 5.2 mol / L within 15 minutes. At the same time, start the cooling system to keep the temperature in the paste mixer below 22 °C. After the dilute sulfuric acid is added, continue stirring for 20 minutes to allow the components to react and mix fully, finally obtaining the positive electrode lead paste.

[0038] Example 4

[0039] Step (1) Raw material addition and dry mixing: Place 1100 g of high-purity lead powder into a paste mixer. Sequentially add 0.7 g of 4-butylsulfonate, 1.0 g of antimony trioxide, 1.2 g of polyester short fibers with a length of 5 mm and a diameter of 30 μm, and 2.0 g of acetylene black conductive carbon material. After sealing, dry mix at a speed of 80 rpm for 8 minutes.

[0040] Step (2) Pure water addition and wet stirring: Slowly pour in 95 g of pure water within 5 minutes while maintaining a stirring speed of 80 rpm. After the pure water is added, continue stirring for 5 minutes.

[0041] Step (3) Addition of acidic auxiliary liquid: Preparation of acidic auxiliary liquid: 12 g of borane dimethylamine complex, 9 g of dioctyltin maleate, 2.5 g of trimethylamine and 130 g of DMF were mixed, stirred at 78 °C for 2.5 hours, and DMF was removed by reduced pressure distillation to obtain a synergist. Then, 2.5 g of the synergist was dissolved in 40 g of 70% by mass dilute sulfuric acid, stirred and mixed for 90 minutes to obtain the desired acidic auxiliary liquid.

[0042] 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.

[0043] Step (4) Addition of dilute sulfuric acid and temperature control: Slowly pour in 90 g of 5.5 mol / L dilute sulfuric acid over 8 minutes. At the same time, start the cooling system to keep the temperature in the paste mixer below 35°C. After adding the dilute sulfuric acid, continue stirring for 10 minutes to allow the components to fully react and mix, and finally obtain the positive lead paste.

[0044] Comparative Example 1 In this example, the acid auxiliary liquid is 70% by mass of dilute sulfuric acid, that is, no synergist is added. The rest of the process is the same as in Example 1.

[0045] Comparative Example 2 In this example, no borane dimethylamine complex was added during the preparation of the acidic auxiliary liquid. The remaining process was consistent with Example 1.

[0046] Comparative Example 3 In this example, no dioctyltin maleate is added during the preparation of the acid auxiliary liquid. The remaining processes are the same as those in Example 1.

[0047] Test Example 1 1. Initial capacity test Test instrument: constant current charge and discharge tester (Arbin test system) is used.

[0048] Sample preparation: According to each embodiment and comparative example, positive lead paste was prepared by the method of the present invention and the traditional process respectively, and positive plates were prepared by the same process. The positive plates used the same substrate and binder, kept other process parameters the same, and assembled into lead-acid batteries.

[0049] Test conditions: Charging: Constant current and constant voltage charging mode is adopted, and the charging cut-off voltage is 2.4 V.

[0050] Discharge: Constant current discharge is adopted, and the test current density is C / 10 (calculated according to the rated capacity).

[0051] Test indicators: 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.

[0052] 2. Cycling life test Test instrument: Use a cycling life test system equipped with a temperature control bath to ensure that the test temperature is kept constant at 25 ± 2 °C.

[0053] Sample preparation: The same as the sample described in the initial specific capacity test.

[0054] Test conditions: Adopt constant current discharge test, and the discharge depth is controlled at 80% (that is, when the capacity decays to 80% of the initial capacity, it is regarded as the end of the cycling life). The charge and discharge cycles are carried out at a current of C / 5.

[0055] Test index: Record the number of charge and discharge cycles when the positive electrode plate reaches 80% of the initial specific capacity to evaluate the cycling life.

[0056] 3. Plate adhesion test Test method: Adopt the peel test method.

[0057] Use a standard peel tester (such as an Instron tensile testing machine) to test the peel force between the lead paste and the current collector on the positive electrode plate at a certain peel speed.

[0058] Test conditions: The peel speed is 50 mm / min. Each sample is tested in at least 3 different areas, and the average value is taken as the final test result.

[0059] Test index: Expressed in peel force per unit area (N / cm²), the greater the peel force, the better the adhesion between the lead paste and the current collector.

[0060] Table 1: Test results of examples and comparative examples

[0061] 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 cycling life of the lead-acid battery are improved, proving the advantages 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 battery according to claim 1, characterized in that: 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 h, and DMF is removed by reduced pressure distillation to obtain the synergist for preparing the positive lead paste of the lead-acid battery.

3. An acidic auxiliary liquid for preparing positive lead paste of lead-acid batteries, characterized in that: The preparation method of the acid 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 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) Solid raw material addition 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 weight; (2) Adding pure water and wet stirring; (3) Addition of acid auxiliary liquid: Pour 1.5-2.5 parts by weight of the acid auxiliary liquid according to claim 3, and stir and mix continuously during the addition process; (4) Addition of dilute sulfuric acid.

5. 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 (1), the positive electrode additive includes: 4-butyl sulfonate, antimony trioxide, polyester short fiber and conductive carbon material. The solid raw material adding and dry mixing steps in step (1) include: 950-1100 parts by weight of high-purity lead powder are placed in a paste mixer; 0.4-0.7 parts by weight of 4-butyl sulfonate, 0.7-1.0 parts by weight of antimony trioxide, 0.9-1.2 parts of polyester staple fibers and 1.4-2.0 parts of conductive carbon materials are added, the paste mixer is closed, and dry-mixed for 5-8 minutes to evenly 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, characterized in that: 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, characterized in that: In step (2), the pure water addition and wet stirring step comprises: slowly pouring in 95 to 110 parts by weight 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), 1.5 to 2.5 parts by weight of the acid 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 to 90 parts by weight of dilute sulfuric acid within 8 to 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 to 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.

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