A negative electrode lead paste for extending the cycle life of a start-stop battery and a preparation method thereof

Abstract

The present invention discloses a negative lead paste for extending the cycle life of a start-stop battery and a preparation method thereof. An additive for the negative lead paste for extending the cycle life of a start-stop battery is used. The additive comprises, by mass, 0.05-0.1 parts of polyester staple fibers, 0.5-1 parts of lamp black, 0.3-0.8 parts of superconducting carbon black, 0.3-0.8 parts of precipitated silica, 0.1-0.4 parts of superconducting graphite, 0.6-1.2 parts of ultrafine barium sulfate, 0.1-0.4 parts of lignin aqueous solution, and 0.1-0.4 parts of humic acid aqueous solution. In the present application, the superconducting carbon black is lead-coated nano superconducting carbon black. The surface of the nano superconducting carbon black is coated with lead, tin, and pyrrole functional groups to obtain lead-coated nano superconducting carbon black. The lead-coated nano superconducting carbon black cooperates with other additives to accelerate the kinetic process of the reaction during the battery charging and discharging process and help slow down the decay rate of the battery capacity, so that the battery can still maintain a high performance after a longer period of use.

Description

Technical Field

[0001] The invention belongs to the technical field of lead-acid batteries, and in particular relates to a negative electrode lead paste for extending the cycle life of a start-stop battery and a preparation method thereof. Background Art

[0002] In recent years, the start-stop technology of automobiles has developed rapidly. After the automobile is equipped with a start-stop system, it can save 5% to 8% of fuel. As an important part of the start-stop system, the start-stop battery has a broad market prospect. The start-stop lead-acid battery needs to be fast in charge and discharge, and also needs to have a high capacity to ensure the normal operation of the electrical appliances in the car after the engine is stopped. Therefore, the start-stop lead-acid battery frequently works under the high-rate partial state of charge (HRPSoC) and is prone to battery failure caused by irreversible sulfation of the negative electrode. Sulfation is the gradual generation of white coarse-grained lead sulfate on the surface of the plate. This grain is very hard and difficult to dissolve. It is not easy to react with the electrolyte during charging, thereby reducing the active substances. In addition, the coarse-grained lead sulfate blocks the pores of the plate, making it difficult for the electrolyte to penetrate, and increases the internal resistance, which reduces the active substances participating in the reaction in the plate. This phenomenon is called "irreversible sulfation". This failure mode often occurs in start-stop batteries because the battery has the following reasons in frequent start-stop:

[0003] (1) Insufficient charging or insufficient charging at the bottom of the acid layer;

[0004] (2) The dissolution and precipitation of lead sulfate are related to temperature. Due to temperature changes (such as temperature increase), part of the lead sulfate on the electrode plate dissolves into the electrolyte. When the temperature drops, the lead sulfate dissolved in the electrolyte will re-precipitate, resulting in recrystallization, forming coarse grains that are deposited on the electrode plate.

[0005] (3) The electrolyte density is too large, the discharge current is too large, the chemical reaction is intensified, and the lead sulfate produced is quickly deposited on the plate, which also promotes sulfidation;

[0006] (4) Since the acid density at the bottom of the plate is higher than that at the top, the charge acceptance capacity at the bottom of the plate is also lower than that at the top, and the sulfidation at the bottom of the plate is more serious than that at the top and middle.

[0007] The invention application with publication number CN117832411A discloses a method for preparing a negative plate of a lead-carbon battery for energy storage. The raw material of the negative plate of the lead-carbon battery comprises: based on 100 parts of lead powder by weight, 0.5-2 parts of a carbon-based additive, 0.05-0.8 parts of barium sulfate, 0.05-0.2 parts of humic acid, 0.05-0.18 parts of acetylene black, 0.05-0.13 parts of short fibers, 0.05-0.2 parts of sodium lignin sulfonate, 10-15 parts of deionized water and 8-10 parts of sulfuric acid. The raw material of the negative plate of the lead-carbon battery of the present invention can suppress the problems of sulfation and hydrogen evolution reaction of the negative electrode active material, and improve the charging acceptance and cycle life of the battery under energy storage application conditions.

[0008] In addition, the invention application with publication number CN116598506A discloses a composite expander and its application in the negative plate of a lead-acid battery. The composite expander includes the following raw materials in parts by weight: 1 to 3 parts of a conductive monomer, 1 to 3 parts of sodium lignin sulfonate, 1 to 5 parts of acrylamide, 10 to 40 parts of anhydrous ethanol and 3 to 9 parts of ammonium persulfate solution. When the negative lead paste prepared based on the composite expander is used in the negative plate of the battery, the deposition of a continuous lead sulfate passivation layer on the negative electrode can be suppressed during discharge of the battery, thereby improving the cycle performance of the battery.

[0009] Although the prior art has disclosed negative electrode additives for extending the cycle life of start-stop batteries, it is still of great significance to develop new negative electrode additives to address the problem of battery failure caused by irreversible sulfation of the negative electrode when the start-stop battery frequently works under HRPSoC. Summary of the invention

[0010] The purpose of the present invention is to provide a negative electrode lead paste for extending the cycle life of a start-stop battery and a preparation method thereof, so as to develop a new negative electrode lead paste formula for extending the cycle life of a start-stop battery, improve the structure and properties of the negative electrode material to make the negative electrode charge and discharge reaction more uniform, and to a certain extent improve the battery's charge acceptance, discharge capacity at different rates and high rate partial state of charge (HRPSoC) cycle life performance.

[0011] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0012] The invention provides an additive for negative electrode lead paste for extending the cycle life of a start-stop battery. The additive comprises, by weight, 0.05-0.1 parts of polyester staple fibers, 0.5-1 parts of lamp black, 0.3-0.8 parts of superconducting carbon black, 0.3-0.8 parts of precipitated silica, 0.1-0.4 parts of superconducting graphite, 0.6-1.2 parts of ultrafine barium sulfate, 0.1-0.4 parts of lignin aqueous solution, and 0.1-0.4 parts of humic acid aqueous solution, wherein the concentrations of the lignin aqueous solution and the humic acid aqueous solution are respectively 10%-15%.

[0013] The present invention uses polyester staple fibers, lamp black, superconducting carbon black and superconducting graphite to cooperate with each other, so that the negative electrode plate absorbs a large amount of oxygen and establishes a channel under the action of the fibers, allowing the superconducting carbon black and superconducting graphite to continuously transmit electrons to the inside and outside of the electrode plate, thereby enhancing the activity of the negative electrode, improving the conductivity, and improving the large current discharge capacity. During the cycle, the structure of the negative electrode pores is optimized, the negative electrode porosity is improved, and the surface area of ​​the electrode plate surface is greatly increased. The addition of superconducting carbon black and superconducting graphite can significantly increase the 17.5% DOD cycle life under low temperature conditions.

[0014] The present invention adopts lignin aqueous solution and humic acid aqueous solution to replace lignin powder and humic acid, which can greatly improve the dispersibility of lignin and humic acid, enable the expander to be more effectively attached to the negative electrode sponge-like lead paste, reduce the surface energy of the negative electrode, thereby better inhibiting the surface shrinkage in the charge and discharge cycle process, more effectively maintaining the porosity and high dispersibility of the negative electrode lead, improving the electrochemical performance of the negative electrode, greatly improving the low-temperature starting ability of the battery, and delaying the premature failure of lignin and humic acid during high-temperature formation or battery use, especially when the start-stop battery is discharged at a high rate and discharged at a low temperature and with a large current; in addition, after the lignin aqueous solution and humic acid aqueous solution replace lignin powder and humic acid, the speed at which lignin and humic acid are dissolved from the negative electrode can be effectively reduced, and the migration of lignin and humic acid organic matter to the positive electrode in the electric field is reduced, so that they are oxidized and decomposed by the positive electrode, thereby extending the cycle life of the battery.

[0015] Preferably, the superconducting carbon black is lead-coated nano superconducting carbon black, and the lead-coated nano superconducting carbon black is subjected to a surface treatment of lead coating, and the steps include:

[0016] Nano superconducting carbon black, lead acrylate, 3-(2-pyrrole)ethyl acrylate, (Z)-3-tributyltin ethyl acrylate, dioctadecylamine and triethylamine are mixed and coated to obtain lead-coated nano superconducting carbon black.

[0017] The present invention uses acrylic lead to provide a lead source and adjust the electrode potential. Carboxyl lead, as a lead source, can provide sufficient lead ions on the electrode surface, which is beneficial to the formation and repair of the lead electrode. In addition, the carboxyl functional group in the carboxyl lead has a certain electronegativity, which can adjust the electrode potential, make the electrode reaction more balanced, and is beneficial to the stable operation of the battery.

[0018] The use of 3-(2-pyrrole) ethyl acrylate can enhance electrode stability and improve electrode interface: pyrrole and its derivatives have good chemical stability and electrochemical activity, can form stable complexes with electrode materials, and enhance the structural stability and corrosion resistance of the electrode; in addition, the nitrogen atom in the pyrrole molecule has lone pairs of electrons, which can form coordination bonds with metal atoms on the electrode surface, improve the electrode interface properties, reduce electrode polarization, and improve the charge and discharge efficiency of the battery.

[0019] The use of (Z)-3-tributyltin ethyl acrylate can inhibit sulfation and promote electron transfer: during the charge and discharge process of lead-acid batteries, the negative electrode lead easily combines with sulfate ions to form insoluble lead sulfate crystals, resulting in a decrease in active substances on the electrode surface and a decrease in battery capacity; tributyltin, as an organic metal compound, can compete with sulfate ions for adsorption, reduce the formation of lead sulfate, and thus inhibit sulfation; in addition, tributyltin has good conductivity and can form a conductive film on the electrode surface, reducing the electrode interface resistance, improving the electron transfer efficiency, and facilitating the battery's charge and discharge reactions.

[0020] Preferably, by mass, for every 100 parts of nano superconducting carbon black, 0.2-0.5 parts of lead acrylate, 0.002-0.04 parts of ethyl 3-(2-pyrrole)acrylate, 0.0003-0.003 parts of (Z)-3-tributyltin ethyl acrylate, 1-4 parts of dioctadecylamine and 0.02-0.3 parts of triethylamine are added.

[0021] The invention adopts lead acrylate, 3-(2-pyrrole)ethyl acrylate and (Z)-3-tributyltin alkylethyl acrylate to react with dioctadecylamine respectively to undergo amino-olefin Michael addition reaction, and the reaction is coated on the surface of nano-scale superconducting carbon black particles to obtain lead-coated nano-superconducting carbon black containing lead, tin and pyrrole functional groups on the surface. The nano-scale superconducting carbon black coated with lead, tin and pyrrole functional groups can effectively extend the cycle life of lead-acid batteries: the tin and lead contained on the surface can be used as active points of electrochemical reactions, and these metal points can be used as media for the conversion of lead dioxide and lead during the battery charging and discharging process, thereby accelerating the kinetic process of the reaction; at the same time, the presence of the pyrrole functional group provides additional chemical active points for improving charge transmission and uniformity of the reaction surface, which helps to maintain the performance of the battery under high load; this configuration reduces the decay rate of the battery capacity, so that the battery can maintain high performance after a longer period of use.

[0022] Preferably, the mixing and coating is carried out in a high-speed mixer, the mixing and coating temperature is 50-70° C., the mixing and coating time is 3-10 min, and the mixing and coating speed is 500-1000 rad / min.

[0023] Preferably, the superconducting carbon black in the additive is lead-coated nano superconducting carbon black with a particle size of 10-50 nm, a resistivity of 0.3-0.5 Ω·cm, and a specific surface area of ​​90-140 m 2 / g.

[0024] Nanoscale superconducting carbon black itself has good electrical conductivity. When its surface is coated with lead complex, it can serve as an effective conductive bridge to enhance the electron transfer efficiency inside the electrode material and between the electrode and the current collector, which is beneficial to the charge and discharge operation of the battery at high current density and improves the overall electrochemical performance of the battery. In addition, superconducting carbon black with high specific surface area can provide a fast double-layer charge and discharge structure. This substance has good affinity with lead and can quickly promote the conversion of divalent lead ions, thereby greatly extending the life of the battery.

[0025] Preferably, the single fiber diameter of the polyester staple fiber in the additive is 10-20 μm and the length is 4-5 mm; the specific surface area of ​​the precipitated silica in the additive is 120-150 m 2 / g.

[0026] The precipitated silica used in the present invention has a porous structure, wherein the primary particles and aggregates inside thereof are combined together to form a macroporous region with a size greater than 50 nm, and is a pore-forming agent with a very obvious effect. The precipitated silica is added to the negative electrode lead paste formula to significantly improve the size and number of the negative electrode pores, firmly adsorb the acid liquid inside the plate, and can not only delay the failure of the negative electrode due to acid stratification, but also well protect the structure of the negative electrode, avoid the expansion of the negative electrode, and thus extend the service life of the battery.

[0027] The present invention further provides a negative electrode lead paste formula for extending the cycle life of a start-stop battery, comprising lead powder, dilute sulfuric acid, pure water and additives, wherein, by mass, the components and addition amounts of the additives corresponding to every 100 parts of lead powder include: 0.05-0.1 parts of polyester staple fibers, 0.5-1 parts of lamp black, 0.3-0.8 parts of superconducting carbon black, 0.3-0.8 parts of precipitated silica, 0.1-0.4 parts of superconducting graphite, 0.6-1.2 parts of ultrafine barium sulfate, 0.1-0.4 parts of lignin aqueous solution, and 0.1-0.4 parts of humic acid aqueous solution, wherein the concentrations of the lignin aqueous solution and the humic acid aqueous solution are each 10%-15%.

[0028] Preferably, the density of dilute sulfuric acid at a temperature of 27°C is 1.4 g / cm3 , by mass, the amount of dilute sulfuric acid added is 7 to 8.5 parts per 100 parts of lead powder; the conductivity of the pure water is ≤1.5 μS / cm, and by mass, the amount of pure water added is 14 to 15 parts per 100 parts of lead powder.

[0029] The present invention also provides a method for preparing the negative electrode lead paste formula for extending the cycle life of the start-stop battery, comprising the following steps:

[0030] (1) First add some lead powder, then spray in some pure water;

[0031] (2) Add the remaining lead powder and spray into some pure water, and mix under normal pressure;

[0032] (3) spraying the remaining amount of pure water except for the amount in steps (1) and (2) and mixing under normal pressure;

[0033] (4) Pause mixing, add the formulated amount of additives and stir;

[0034] (5) After evacuating the vacuum, add the formulated amount of dilute sulfuric acid, mix under vacuum and then mix under normal pressure to obtain the negative electrode lead paste for extending the cycle life of the start-stop battery.

[0035] A vacuum paste machine is used to prepare negative electrode lead paste. The inclined paste machine automatically moves toward the agitator under the action of gravity to assist mixing. The mixing disk of the vacuum paste machine rotates at a certain speed, and the agitator and the mixing disk move in opposite directions, ensuring a high relative speed between the lead paste and the agitator.

[0036] The speed of adding lead powder in steps (1) and (2) of the preparation method is 200-270 kg / min.

[0037] In steps (1) to (3) of the preparation method, atomized pure water is sprayed using a pure water nozzle with a size of 60 to 100 μm; wherein, by mass, 30 to 35 parts of atomized pure water are added for every 100 parts of pure water, and the flow rate of pure water is 7 to 15 min.

[0038] Preferably, the amount of lead powder added in step (1) is 50% of the total amount of lead powder, and the amount of pure water added is 35% of the total amount of pure water;

[0039] The amount of pure water added in step (2) is 30% of the total amount of pure water.

[0040] By stirring the lead powder and atomized pure water for many times, the lead powder and the atomized pure water can be fully contacted, the reaction area of ​​the lead powder and the atomized pure water is increased, and the reaction efficiency is improved.

[0041] In step (2) of the preparation method, the mixture is mixed at normal pressure for 2 to 3 minutes, in step (3), the mixture is mixed at normal pressure for 1.5 to 2 minutes, and in step (5), the mixture is mixed at normal pressure for 10 seconds.

[0042] The acid addition rate of the formulated amount of dilute sulfuric acid added in step (5) of the preparation method is 10-15 kg / min.

[0043] In step (5) of the preparation method, the vacuuming time is 30 s, and the vacuuming is performed by applying a vacuum pressure of 100-120 mbar, and the mixing is performed under vacuum conditions for 240-300 s.

[0044] The vacuum and paste machine controls the temperature of the lead paste by adjusting the vacuum pressure and is not affected by the external environment.

[0045] The beneficial effects of the present invention are:

[0046] (1) The negative electrode lead paste for extending the cycle life of a start-stop battery provided by the present invention uses polyester staple fiber, lamp black, superconducting carbon black, superconducting graphite, precipitated silica, ultrafine barium sulfate, lignin aqueous solution and humic acid aqueous solution as additives to cooperate with each other, wherein the superconducting carbon black is subjected to lead-coated surface treatment to obtain lead-coated nano superconducting carbon black, which can form a more uniform and stable conductive network on the electrode surface, help improve the reversibility of the battery during charging and discharging, reduce the degradation and structural damage of the electrode material, increase the active surface area of ​​the electrode, and provide more electrochemical reaction sites, which helps to maintain the performance of the battery under high load. This material configuration reduces the decay rate of the battery capacity, allowing the battery to maintain high performance after longer use.

[0047] (2) The preparation method of negative electrode lead paste provided by the present invention adopts vacuum paste machine equipment, atomized pure water and additives to cooperate with each other to prepare negative electrode lead paste. In the preparation method and process, the vacuum paste machine controls the temperature of the lead paste by vacuum pressure and is not affected by the external environment, so that the composition of the prepared lead paste is more stable and more uniform, thereby greatly extending the service life of the battery. DETAILED DESCRIPTION

[0048] Example 1

[0049] First, weigh the following components according to the following weight ratios: 100 parts lead powder, 14.2 parts pure water, density 1.4 g / cm 3 7 parts of dilute sulfuric acid (temperature 27 °C), 0.05 parts of polyester staple fiber, 0.5 parts of lamp black, 0.4 parts of lead-coated nano superconducting carbon black (particle size 10 nm, resistivity 0.4 Ω·cm, specific surface area 90 m 2 / g), 0.3 parts of precipitated silica, 0.1 parts of superconducting graphite, 0.7 parts of ultrafine barium sulfate, 0.15 parts of lignin aqueous solution, and 0.2 parts of humic acid aqueous solution.

[0050] Preparation steps of lead-coated nano superconducting carbon black:

[0051] Nano superconducting carbon black was placed in a high-speed mixer, and 0.2 parts of lead acrylate, 0.002 parts of 3-(2-pyrrole)ethyl acrylate, 0.0003 parts of (Z)-3-tributyltin ethyl acrylate, 1 part of dioctadecylamine and 0.02 parts of triethylamine were added to every 100 parts of nano superconducting carbon black, by weight. The mixture was mixed in a high-speed mixer, and the mixing and coating time was 3 min at 50°C, and the mixing and coating speed was 500 rad / min to obtain lead-coated nano superconducting carbon black.

[0052] Prepare lead paste as follows:

[0053] 1) Based on 100 parts of lead powder, add 50 parts of lead powder into the vacuum paste machine, and the feeding speed of lead powder is 200 kg / min;

[0054] 2) Use pure water nozzle 1 (size is 60 μm) to add atomized pure water. By mass, 35 parts of atomized pure water are sprayed for every 100 parts of pure water. The flow rate of pure water is 7 L / min.

[0055] 3) Add the remaining lead powder into the vacuum paste machine at a feeding rate of 200 kg / min;

[0056] 4) Use pure water nozzle 2 (size is 80 μm) to add atomized pure water. By mass, 30 parts of atomized pure water are sprayed for every 100 parts of pure water. The flow rate of pure water is 10 L / min.

[0057] 5) Mix at normal pressure for 2 min;

[0058] 6) Use pure water nozzle 2 (size is 80 μm) to add atomized pure water. By mass, 35 parts of atomized pure water are sprayed for every 100 parts of pure water. The flow rate of pure water is 10 L / min.

[0059] 7) Mix at normal pressure for 1.5 min;

[0060] 8) Pause the vacuum and paste machine, add the prepared polyester staple fiber, lamp black, lead-coated nano superconducting carbon black, precipitated silica, superconducting graphite, ultrafine barium sulfate, lignin aqueous solution and humic acid aqueous solution and stir for 4 minutes;

[0061] 9) Vacuum for 30 s, vacuum pressure 100 mbar;

[0062] 10) Add the formulated amount of dilute sulfuric acid at a rate of 10 kg / min;

[0063] 11) Vacuum mix for 240 s;

[0064] 12) Mix at normal pressure for 10 s.

[0065] After vacuum and paste, negative lead paste is obtained, and the apparent density range is 3.75 g / cm 3 The calculation formula is ρ=(m2-m1) / V, where ρ is the apparent density of the lead paste, m2 is the total weight of the lead cup and the lead paste to be tested, m1 is the known weight of the lead cup, and V is the internal volume of the lead cup.

[0066] Example 2

[0067] First, weigh the following components according to the following weight ratios: 100 parts lead powder, 14.6 parts pure water, density 1.4 g / cm 3 7.6 parts of dilute sulfuric acid (temperature 27 °C), 0.08 parts of polyester staple fiber, 0.7 parts of lamp black, 0.7 parts of lead-coated nano superconducting carbon black (particle size 30 nm, resistivity 0.4 Ω·cm, specific surface area 115 m 2 / g), 0.5 parts of precipitated silica, 0.2 parts of superconducting graphite, 0.8 parts of ultrafine barium sulfate, 0.15 parts of lignin aqueous solution, and 0.15 parts of humic acid aqueous solution.

[0068] Preparation steps of lead-coated nano superconducting carbon black:

[0069] Nano superconducting carbon black was placed in a high-speed mixer, and 0.3 parts of lead acrylate, 0.001 parts of 3-(2-pyrrole)ethyl acrylate, 0.001 parts of (Z)-3-tributyltin ethyl acrylate, 2 parts of dioctadecylamine and 0.08 parts of triethylamine were added to every 100 parts of nano superconducting carbon black, and mixed in a high-speed mixer. The mixing and coating time was 7 min at 60 ° C, and the mixing and coating speed was 700 rad / min to obtain lead-coated nano superconducting carbon black.

[0070] Prepare lead paste as follows:

[0071] 1) Based on 100 parts of lead powder, add 50 parts of lead powder into the vacuum paste machine, and the feeding speed of lead powder is 235 kg / min;

[0072] 2) Use pure water nozzle 1 (size is 70 μm) to add atomized pure water. By mass, 35 parts of atomized pure water are sprayed for every 100 parts of pure water. The flow rate of pure water is 9.5 L / min.

[0073] 3) Add the remaining lead powder into the vacuum paste machine at a feeding rate of 235 kg / min;

[0074] 4) Use pure water nozzle 2 (size is 90 μm) to add atomized pure water. By mass, 30 parts of atomized pure water are sprayed for every 100 parts of pure water. The flow rate of pure water is 13 L / min.

[0075] 5) Mix at normal pressure for 2.5 min;

[0076] 6) Use pure water nozzle 2 (size is 90 μm) to add atomized pure water. By mass, 35 parts of atomized pure water are sprayed for every 100 parts of pure water. The flow rate of pure water is 13 L / min.

[0077] 7) Mix at normal pressure for 2 min;

[0078] 8) Pause the vacuum and paste machine, add the prepared polyester staple fiber, lamp black, lead-coated nano superconducting carbon black, precipitated silica, superconducting graphite, ultrafine barium sulfate, lignin aqueous solution and humic acid aqueous solution, and stir for 4.5 minutes;

[0079] 9) Vacuum for 30 s, vacuum pressure 110 mbar;

[0080] 10) Add the formulated amount of dilute sulfuric acid at a rate of 13 kg / min;

[0081] 11) Vacuum mixing for 270 s;

[0082] 12) Mix at normal pressure for 10 s.

[0083] After vacuum and paste, negative lead paste is obtained, and the apparent density range is 3.85 g / cm 3 The calculation formula is ρ=(m2-m1) / V, where ρ is the apparent density of the lead paste, m2 is the total weight of the lead cup and the lead paste to be tested, m1 is the known weight of the lead cup, and V is the internal volume of the lead cup.

[0084] Example 3

[0085] First, weigh the following components according to the following weight ratios: 100 parts lead powder, 14.8 parts pure water, density 1.4 g / cm 3 8.2 parts of dilute sulfuric acid (temperature 27 °C), 0.07 parts of polyester staple fiber, 1.0 parts of lamp black, 0.5 parts of lead-coated nano superconducting carbon black (particle size 50 nm, resistivity 0.5 Ω·cm, specific surface area 140 m 2 / g), 0.7 parts of precipitated silica, 0.2 parts of superconducting graphite, 1.0 parts of ultrafine barium sulfate, 0.25 parts of lignin aqueous solution, and 0.25 parts of humic acid aqueous solution.

[0086] Preparation steps of lead-coated nano superconducting carbon black:

[0087] Nano superconducting carbon black was placed in a high-speed mixer, and 0.5 parts of lead acrylate, 0.04 parts of 3-(2-pyrrole)ethyl acrylate, 0.003 parts of (Z)-3-tributyltin ethyl acrylate, 4 parts of dioctadecylamine and 0.3 parts of triethylamine were added to every 100 parts of nano superconducting carbon black by weight. The mixture was mixed in a high-speed mixer, and the mixing and coating time was 10 min at 70 ° C. The mixing and coating speed was 1000 rad / min to obtain lead-coated nano superconducting carbon black.

[0088] Prepare lead paste as follows:

[0089] 1) Based on 100 parts of lead powder, add 50 parts of lead powder into the vacuum paste machine, and the feeding speed of lead powder is 270 kg / min;

[0090] 2) Use pure water nozzle 1 (size is 80 μm) to add atomized pure water. By mass, 35 parts of atomized pure water are sprayed for every 100 parts of pure water. The flow rate of pure water is 10 L / min.

[0091] 3) Add the remaining lead powder into the vacuum paste machine at a feeding rate of 270 kg / min;

[0092] 4) Use pure water nozzle 2 (size is 100 μm) to add atomized pure water. By mass, 30 parts of atomized pure water are sprayed for every 100 parts of pure water. The flow rate of pure water is 15 L / min.

[0093] 5) Mix at normal pressure for 3 min;

[0094] 6) Use pure water nozzle 2 (size is 100 μm) to add atomized pure water. By mass, 35 parts of atomized pure water are sprayed for every 100 parts of pure water. The flow rate of pure water is 15 L / min.

[0095] 7) Mix at normal pressure for 2 min;

[0096] 8) Pause the vacuum and paste machine, add the prepared polyester staple fiber, lamp black, lead-coated nano superconducting carbon black, precipitated silica, superconducting graphite, ultrafine barium sulfate, lignin aqueous solution and humic acid aqueous solution, and stir for 5 minutes;

[0097] 9) Vacuum for 30 s, vacuum pressure 120 mbar;

[0098] 10) Add the formulated amount of dilute sulfuric acid at a rate of 15 kg / min;

[0099] 11) Vacuum mix for 300 s;

[0100] 12) Mix at normal pressure for 10 s.

[0101] After vacuum and paste, negative lead paste is obtained, and the apparent density range is 3.95 g / cm 3 The calculation formula is ρ=(m2-m1) / V, where ρ is the apparent density of the lead paste, m2 is the total weight of the lead cup and the lead paste to be tested, m1 is the known weight of the lead cup, and V is the internal volume of the lead cup.

[0102] Comparative Example 1

[0103] First, weigh the following components according to the following weight ratio: 100 parts lead powder, 9 parts pure water, density 1.4 g / cm 3 7 parts of dilute sulfuric acid (temperature 27°C), 0.07 parts of polyester staple fiber, 0.2 parts of lamp black, 0.65 parts of precipitated barium sulfate, and 0.2 parts of lignin.

[0104] Prepare lead paste as follows:

[0105] 1) Pour the prepared formula into the paste mixing machine;

[0106] 2) Add 100 parts of lead powder into the vacuum paste machine at a feeding rate of 300 kg / min;

[0107] 2) Add 9 parts of pure water, 80 L / min;

[0108] 3) Mix at normal pressure for 2 min;

[0109] 4) Evacuate the pressure to 80 mbar and add the formulated amount of dilute sulfuric acid at a rate of 12 kg / min;

[0110] 5) Vacuum mixing for 240 s;

[0111] 6) Mix at normal pressure for 10 s.

[0112] After vacuum and paste, negative lead paste is obtained, and the apparent density range is 4.5 g / cm 3 The calculation formula is ρ=(m2-m1) / V, where ρ is the apparent density of the lead paste, m2 is the total weight of the lead cup and the lead paste to be tested, m1 is the known weight of the lead cup, and V is the internal volume of the lead cup.

[0113] Test Example 1

[0114] The negative electrode lead paste prepared in each embodiment and comparative example 1 is applied to the negative electrode grid to obtain a negative electrode plate, and then an EFB start-stop battery is made through the automobile start-stop battery preparation process, and the battery model is 6-QTPE-70 (700). The prepared battery is tested according to the German Volkswagen VW 75073-2019 test standard at 27 ° C, 17.5% DOD cycle life (≥18 units) and 17.5% DOD cycle life under continuous state (≥1020 times). Combined with the EFB start-stop battery 6-QTPE-70 (700) prepared in Examples 1 to 3 and Comparative Example 1, the comparison test life results are shown in Table 1 below:

[0115] Table 1

[0116]

[0117] It can be seen from the results in Table 1 that the cycle life of Examples 1 to 3 meets the requirements of the German Volkswagen standard, while the cycle life of Comparative Example 1 does not meet the requirements of the German Volkswagen standard.

Claims

1. An additive for negative electrode lead paste for extending the cycle life of a start-stop battery, characterized in that: The invention comprises, by weight: 0.05-0.1 parts of polyester staple fibers, 0.5-1 parts of lamp black, 0.3-0.8 parts of superconducting carbon black, 0.3-0.8 parts of precipitated silica, 0.1-0.4 parts of superconducting graphite, 0.6-1.2 parts of superfine barium sulfate, 0.1-0.4 parts of lignin aqueous solution, and 0.1-0.4 parts of humic acid aqueous solution, wherein the concentrations of the lignin aqueous solution and the humic acid aqueous solution are 10%-15% respectively; the superconducting carbon black is lead-coated nano superconducting carbon black, and the surface of the nano superconducting carbon black is subjected to lead-coating surface treatment to obtain the lead-coated nano superconducting carbon black, and the steps include: Nano superconducting carbon black, lead acrylate, 3-(2-pyrrole)ethyl acrylate, (Z)-3-tributyltin ethyl acrylate, dioctadecylamine and triethylamine are mixed and coated to obtain lead-coated nano superconducting carbon black.

2. The additive according to claim 1, characterized in that By mass, for every 100 parts of nano superconducting carbon black, 0.2-0.5 parts of lead acrylate, 0.002-0.04 parts of 3-(2-pyrrole)ethyl acrylate, 0.0003-0.003 parts of (Z)-3-tributyltin ethyl acrylate, 1-4 parts of dioctadecylamine and 0.02-0.3 parts of triethylamine are added.

3. The additive according to claim 1, characterized in that The mixing and coating is carried out in a high-speed mixer, the mixing and coating temperature is 50-70°C, the mixing and coating time is 3-10 min, and the mixing and coating speed is 500-1000 rad / min.

4. The additive according to claim 1, characterized in that The superconducting carbon black is lead-coated nano superconducting carbon black with a particle size of 10-50 nm, a resistivity of 0.3-0.5 Ω·cm, and a specific surface area of ​​90-140 m 2 / g.

5. The additive according to claim 1, characterized in that The single fiber diameter of the polyester staple fiber is 10-20 μm and the length is 4-5 mm; the specific surface area of ​​the precipitated silica is 120-150 m 2 / g.

6. A negative electrode lead paste for extending the cycle life of a start-stop battery, comprising lead powder, dilute sulfuric acid, pure water and additives, characterized in that: The components and addition amounts of the additives corresponding to every 100 parts of lead powder include: 0.05-0.1 parts of polyester staple fibers, 0.5-1 parts of lamp black, 0.3-0.8 parts of superconducting carbon black, 0.3-0.8 parts of precipitated silica, 0.1-0.4 parts of superconducting graphite, 0.6-1.2 parts of ultrafine barium sulfate, 0.1-0.4 parts of lignin aqueous solution, and 0.1-0.4 parts of humic acid aqueous solution, wherein the concentrations of the lignin aqueous solution and the humic acid aqueous solution are 10%-15% respectively; the superconducting carbon black is lead-coated nano superconducting carbon black, and the surface of the nano superconducting carbon black is subjected to lead-coating surface treatment to obtain the lead-coated nano superconducting carbon black, and the steps include: Nano superconducting carbon black, lead acrylate, 3-(2-pyrrole)ethyl acrylate, (Z)-3-tributyltin ethyl acrylate, dioctadecylamine and triethylamine are mixed and coated to obtain lead-coated nano superconducting carbon black.

7. The negative electrode lead paste for extending the cycle life of a start-stop battery according to claim 6, characterized in that: The density of the dilute sulfuric acid at a temperature of 27°C is 1.4 g / cm 3 , by mass, the amount of dilute sulfuric acid added is 7-8.5 parts per 100 parts of lead powder; The conductivity of the pure water is ≤1.5 μS / cm. The amount of pure water added is 14-15 parts per 100 parts of lead powder.

8. The method for preparing the negative electrode lead paste for extending the cycle life of a start-stop battery according to claim 6 or 7, characterized in that: The following steps are involved: (1) First add some lead powder, then spray in some pure water; (2) Add the remaining lead powder and spray into some pure water, and mix under normal pressure; (3) spraying the remaining amount of pure water except for the amount in steps (1) and (2) and mixing under normal pressure; (4) Pause mixing, add the formulated amount of additives and stir; (5) After evacuating the vacuum, add the formulated amount of dilute sulfuric acid, mix under vacuum and then mix under normal pressure to obtain the negative electrode lead paste for extending the cycle life of the start-stop battery.

9. The method for preparing the negative electrode lead paste for extending the cycle life of the start-stop battery according to claim 8, characterized in that: The amount of lead powder added in step (1) is 50% of the total amount of lead powder, and the amount of pure water added is 35% of the total amount of pure water; The amount of pure water added in step (2) is 30% of the total amount of pure water.

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