A positive electrode paste for lead-acid batteries and its preparation method

Abstract

This invention provides a lead paste for the positive electrode of a lead-acid battery and its preparation method. This invention also provides a rare earth-carbon-based composite lead-acid battery positive electrode additive formulation, comprising, by weight: 25-35 parts of carbon material, wherein the carbon material includes carbon nanotubes, graphene, and expanded graphite, with a mass ratio of carbon nanotubes, graphene, and expanded graphite of 1:2:3; 20-30 parts of binder; 8-12 parts of SnO2-rare earth mixture, wherein the rare earth element includes Ce, with a molar ratio of Ce to Sn of 1:8-10; 30-40 parts of 4BS seed crystals; 50-80 parts of nano-red lead powder; 1-1.5 parts of polyester fiber; and 5-10 parts of sodium perborate. This invention constructs a multidimensional conductive network by combining carbon nanotubes, graphene, expanded graphite, and conductive binder to form a stable three-dimensional network, thus solving the problem of anisotropy in the conductivity of traditional lead paste. It also forms a heterojunction through a mixture of SnO2 and rare earth elements, reducing the oxygen evolution overpotential, refining the grains, and inhibiting the corrosion of the positive electrode grid.

Description

Technical Field

[0001] This invention relates to the field of lead-acid battery technology, specifically to a lead-acid battery positive electrode paste and its preparation method. Background Technology

[0002] Lead-acid batteries are widely used due to their low cost and high safety, but the performance of their positive electrode is a significant bottleneck:

[0003] Low utilization rate of active materials: Due to poor conductivity and ion diffusion resistance, only about 50% of the active materials participate in the reaction.

[0004] Short cycle life: The softening and shedding of active materials leads to rapid capacity decay, especially at deep discharge (DOD > 50%).

[0005] Poor low-temperature performance: Traditional lead paste exhibits increased electrolyte viscosity at low temperatures, hindering ion transport and causing a sharp drop in discharge capacity.

[0006] Therefore, improvements to the positive electrode of lead-acid batteries are particularly important.

[0007] For example, patent application CN117855467A discloses a positive electrode paste for lead-acid batteries, comprising lead powder and additives. By weight of the positive electrode paste, the additives include 0.3%–2% calcium peroxide, 0.2%–0.3% expanded graphite, 0.05%–0.1% graphene, 0.8%–1% tetrabasic lead sulfate, 0.1%–0.3% metal sulfate, and 0.1%–0.15% polyester staple fiber. A 4BS framework structure is formed through high-temperature curing. Calcium peroxide decomposes oxygen, promoting the oxidation of free lead and improving the binding force of the active material. This method can increase the cycle life of the product by 15%, but it does not solve the problem of conductive anisotropy, and the decomposition rate of calcium peroxide is difficult to control.

[0008] For example, patent application CN118472190A discloses a positive electrode paste for high-capacity, long-life batteries, comprising lead powder, dilute sulfuric acid, water, and additives. By weight, the additives added to every 1000 parts of lead powder include: 1-3 parts sodium perborate; 0.5-2 parts 4BS; 1-3 parts antimony trioxide; 1-3 parts tin pyrophosphate; 2-4 parts polyolefin; 2-4 parts conductive carbon material; and 1-1.5 parts polyester short fibers. The conductive carbon material is at least one of the following: acetylene black, graphite, graphene, fullerene, and carbon nanotubes. However, the added graphene, carbon nanotubes, and expanded graphite are prone to agglomeration and structural collapse.

[0009] In summary, existing technologies still have the following three major shortcomings:

[0010] (1) The conductive network of traditional carbon materials (such as graphite) is a two-dimensional or partially three-dimensional structure, which cannot penetrate the internal pores of lead paste, resulting in the break of electron transport path and the limited reaction area of ​​active material.

[0011] (2) The traditional curing temperature fluctuation (70-85℃) leads to large size differences in 4BS whiskers (length-to-diameter ratio <10:1) and a porosity of only about 40%, resulting in uneven electrolyte penetration, increased polarization, and decreased charging efficiency.

[0012] (3) SnO2 alone has limited catalytic activity and cannot effectively reduce the oxygen evolution energy barrier (the traditional scheme Δη≥200mV), which leads to increased water decomposition during charging and increased grid corrosion rate. Summary of the Invention

[0013] To address the aforementioned technical problems in the existing technology, this invention provides a lead-acid battery positive electrode paste and its preparation method.

[0014] This invention provides a rare earth-carbon-based composite lead-acid battery cathode additive formulation, comprising, by weight:

[0015] 25-35 parts of carbon material, wherein the carbon material includes carbon nanotubes, graphene and expanded graphite;

[0016] 20-30 parts of adhesive;

[0017] 8 to 12 parts of SnO2-rare earth mixture, wherein rare earth includes Ce element, and the molar ratio of Ce element to Sn element is 1:8 to 10;

[0018] 30-40 parts of 4BS seed crystals;

[0019] 50-80 parts of nano red lead powder;

[0020] 1 to 1.5 parts polyester fiber;

[0021] Sodium perborate, 5-10 parts.

[0022] Preferably, the binder is sulfonated polyaniline. Sulfonated polyaniline is hydrophilic, allowing for better and more uniform mixing in the lead paste. As a conductive agent, sulfonated polyaniline has high adsorption capacity, effectively adsorbing the electrolyte and thus improving the contact and penetration of the sulfuric acid electrolyte into the active material of the electrode plates, relatively increasing the utilization rate of the active material. Furthermore, it can increase the porosity of the active material, thereby improving the initial capacity and charge acceptance of the battery.

[0023] Preferably, the mass ratio of the carbon nanotubes, graphene, and expanded graphite is 1:2:3.

[0024] Preferably, the SnO2-rare earth mixture is a mixture of SnO2 and rare earth elements or a mixture of SnO2 and rare earth oxides.

[0025] The present invention also provides a method for preparing lead-acid battery positive electrode paste, wherein the raw materials for preparing lead-acid battery positive electrode paste include lead powder, dilute sulfuric acid, water and each material in the above-mentioned rare earth-carbon based composite lead-acid battery positive electrode additive formula.

[0026] The mass ratio of lead powder and carbon material in the rare earth-carbon-based composite lead-acid battery cathode additive formulation is 1000:25-35;

[0027] The preparation method includes the following steps:

[0028] (1) The red lead powder, 4BS seed crystals and SnO2-rare earth mixture of the formula amount were ball-milled and mixed in an inert gas atmosphere, and the nano-sized powder was obtained by sieving to prepare pre-additive A.

[0029] (2) Mix and emulsify the carbon material, binder and water in the specified amounts to obtain emulsion B;

[0030] (3) Dry mix the lead powder, sodium perborate, polyester fiber and pre-made additive A according to the formula, then add emulsion B and water, mix evenly, then add dilute sulfuric acid, mix evenly and then make paste.

[0031] Preferably, in the raw materials for preparing the positive electrode lead paste for lead-acid batteries, by mass, every 1000 parts of lead powder corresponds to 90-105 parts of dilute sulfuric acid, and every 1000 parts of lead powder corresponds to 110-130 parts of water.

[0032] Preferably, in step (1), the ball milling is carried out in a ball mill, and hard grinding balls are also added to the ball mill. The mass ratio of the hard grinding balls to the added raw materials is 10:1. The rotation speed of the ball mill is 500-1000 rpm, and the ball milling time is 20-30 hours. The sieve used for sieving has a sieve aperture of 60 nm. The red lead powder, 4BS seed crystals, and SnO2-rare earth mixture are ball-milled to a particle size ≤60 nm to improve the interfacial reaction activity.

[0033] Preferably, in step (2), an ultrasonic emulsifier is used for mixing and emulsification. The shearing speed of the ultrasonic emulsifier during mixing and emulsification is 2500-3000 r / min, and the mixing and emulsification time is 45-60 min.

[0034] Preferably, in step (3), the paste discharge temperature is not higher than 45°C.

[0035] The present invention also provides a lead-acid battery positive electrode paste, which is prepared by the above-mentioned method for preparing lead-acid battery positive electrode paste.

[0036] The present invention also provides a lead-acid battery, including a positive electrode plate, wherein the positive electrode plate is prepared by coating the positive electrode lead paste of the above-mentioned lead-acid battery onto the positive electrode plate grid and then curing it at high temperature. The high temperature curing temperature is 75-80°C, the time is 8-10 hours, and the ambient humidity is controlled within the range of 90%-95% relative humidity (RH).

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] (1) A multidimensional conductive network is constructed by combining carbon nanotubes (1D) + graphene (2D) + expanded graphite (3D) + conductive binder. Expanded graphite fills the gaps between graphene sheets, and the conductive bonding effect of the binder forms a stable three-dimensional network. Carbon nanotubes act as “wires” to connect graphene sheets, and expanded graphite provides pore support, solving the problem of anisotropy in conductivity of traditional lead paste and forming an omnidirectional conductive path.

[0039] (2) The SnO2-rare earth mixture forms a heterojunction, which reduces the oxygen evolution overpotential, refines the grains, inhibits the corrosion of the positive electrode grid, reduces the decomposition of water during the charging process, improves the charging efficiency, and extends the electrode life.

[0040] (3) Sodium perborate can improve the bonding force between the grid and the active material, prevent the active material of the plate from falling off, and sodium perborate will decompose in humid air or when slightly heated and release oxygen. Combined with 4BS seed crystals to guide the growth of three-dimensional whisker structure, it is conducive to the formation of PbO, reduces the content of free lead, and thus improves the performance of lead-acid battery. Detailed Implementation

[0041] Example 1

[0042] 1. Nano-scale pretreatment of additive component A:

[0043] (1) Add 50 parts of red lead powder, 30 parts of 4BS seed crystals and 8 parts of SnO2-rare earth mixture (SnO2-rare earth mixture is a mixture of SnO2 and Ce elements, wherein the molar ratio of Ce to Sn is 1:8) into a high-energy ball mill. Load hard grinding balls (zirconia and tungsten carbide in a mass ratio of 1:1) into the ball mill jar. The mass ratio of the added powder to the hard grinding balls is 1:10.

[0044] (2) Inert gas—argon—is introduced into the ball mill jar to prevent the powder material from being oxidized during the grinding process.

[0045] (3) Set the rotation speed (500 rpm) and grinding time (20 hours), and run intermittently to avoid overheating.

[0046] (4) After grinding, the grinding balls are separated by sieving, and the nano powder is sieved at the same time (sieve aperture is 60nm) to obtain pretreated nano-level additive A.

[0047] 2. Additive B component water emulsification treatment

[0048] Add 25 parts of composite carbon material (carbon nanotubes: graphene: expanded graphite mass ratio = 1:2:3) and 40 parts of deionized water to an ultrasonic emulsifier. Stir at low speed for 30 minutes to fully wet the material. Then add 20 parts of sulfonated polyaniline binder (supplier: Shanghai Chuangsai Technology Co., Ltd.; product name: polyaniline, 98%, sulfonic acid doped; the same below). Increase the shear speed of the emulsifier to 2500 r / min and emulsify for 45 minutes to obtain emulsion B.

[0049] 3. Lead paste preparation process

[0050] Add 1000 parts lead powder, 5 parts sodium perborate, 1 part polyester fiber, and premixed additive A to the paste mixer and start the dry mixing machine for 5 minutes. Then, spray the pretreated additive component B into the agitated lead paste in the paste mixer in a mist form over 5 minutes. Next, pour in 70 parts deionized water over 3 minutes, and continue stirring for 5 minutes after the addition is complete. Then, pour in 90 parts dilute sulfuric acid over 8 minutes, and continue stirring for 10 minutes after the addition is complete. Stop the machine when the temperature drops below 45 degrees Celsius.

[0051] 4. The electrode plate adopts high-temperature curing technology. The high-temperature curing stage is at 75℃ for 8 hours and 90%RH. This ensures that sodium perborate decomposes when heated to produce oxygen, which promotes grid oxidation and further oxidation of free lead in lead paste.

[0052] Example 2

[0053] 1. Nano-scale pretreatment of additive component A:

[0054] (1) Add 50 parts of red lead powder, 30 parts of 4BS seed crystals and 8 parts of SnO2-rare earth mixture (SnO2-rare earth mixture is a mixture of SnO2 and Ce element, wherein the molar ratio of Ce element to Sn element is 1:9) into a high-energy ball mill. Load hard grinding balls (zirconia and tungsten carbide in a mass ratio of 1:1) into the ball mill jar. The mass ratio of the added powder material to the hard grinding balls is 1:10.

[0055] (2) Inert gas—argon—is introduced into the ball mill jar to prevent the powder material from being oxidized during the grinding process.

[0056] (3) Set the rotation speed (500 rpm) and grinding time (20 hours), and run intermittently to avoid overheating.

[0057] (4) After grinding, the grinding balls are separated by sieving, and the nano powder is sieved at the same time (sieve aperture is 60nm) to obtain pretreated nano-level additive A.

[0058] 2. Additive B component water emulsification treatment

[0059] Add 25 parts of composite carbon material (carbon nanotubes: graphene: expanded graphite mass ratio = 1:2:3) and 40 parts of deionized water to an ultrasonic emulsifier, stir at low speed for 30 minutes to fully wet the material, then add 20 parts of sulfonated polyaniline binder, increase the shear speed of the emulsifier to 2500 r / min, and emulsify for 45 minutes to obtain emulsion B.

[0060] 3. Lead paste preparation process

[0061] Add 1000 parts lead powder, 5 parts sodium perborate, 1 part polyester fiber, and premixed additive A to the paste mixer and start the dry mixing machine for 5 minutes. Then, spray the pretreated additive component B into the agitated lead paste in the paste mixer in a mist form over 5 minutes. Next, pour in 70 parts deionized water over 3 minutes, and continue stirring for 5 minutes after the addition is complete. Then, pour in 90 parts dilute sulfuric acid over 8 minutes, and continue stirring for 10 minutes after the addition is complete. Stop the machine when the temperature drops below 45 degrees Celsius.

[0062] 4. The electrode plate adopts high-temperature curing technology. The high-temperature curing stage is at 75℃ for 8 hours and 90%RH. This ensures that sodium perborate decomposes when heated to produce oxygen, which promotes grid oxidation and further oxidation of free lead in lead paste.

[0063] Example 3

[0064] 1. Nano-scale pretreatment of additive component A:

[0065] (1) Add 50 parts of red lead powder, 30 parts of 4BS seed crystals and 8 parts of SnO2-rare earth mixture (SnO2-rare earth mixture is a mixture of SnO2 and Ce elements, wherein the molar ratio of Ce to Sn is 1:10) into a high-energy ball mill. Load hard grinding balls (zirconia and tungsten carbide in a mass ratio of 1:1) into the ball mill jar. The mass ratio of the added powder to the hard grinding balls is 1:10.

[0066] (2) Inert gas—argon—is introduced into the ball mill jar to prevent the powder material from being oxidized during the grinding process.

[0067] (3) Set the rotation speed (500 rpm) and grinding time (20 hours), and run intermittently to avoid overheating.

[0068] (4) After grinding, the grinding balls are separated by sieving, and the nano powder is sieved at the same time (sieve aperture is 60nm) to obtain pretreated nano-level additive A.

[0069] 2. Additive B component water emulsification treatment

[0070] Add 25 parts of composite carbon material (carbon nanotubes: graphene: expanded graphite mass ratio = 1:2:3) and 40 parts of deionized water to an ultrasonic emulsifier, stir at low speed for 30 minutes to fully wet the material, then add 20 parts of sulfonated polyaniline binder, increase the shear speed of the emulsifier to 2500 r / min, and emulsify for 45 minutes to obtain emulsion B.

[0071] 3. Lead paste preparation process

[0072] Add 1000 parts lead powder, 5 parts sodium perborate, 1 part polyester fiber, and premixed additive A to the paste mixer and start the dry mixing machine for 5 minutes. Then, spray the pretreated additive component B into the agitated lead paste in the paste mixer in a mist form over 5 minutes. Next, pour in 70 parts deionized water over 3 minutes, and continue stirring for 5 minutes after the addition is complete. Then, pour in 90 parts dilute sulfuric acid over 8 minutes, and continue stirring for 10 minutes after the addition is complete. Stop the machine when the temperature drops below 45 degrees Celsius.

[0073] 4. The electrode plate adopts high-temperature curing technology. The high-temperature curing stage is at 75℃ for 8 hours and 90%RH. This ensures that sodium perborate decomposes when heated to produce oxygen, which promotes grid oxidation and further oxidation of free lead in lead paste.

[0074] Example 4

[0075] 1. Nano-scale pretreatment of additive component A:

[0076] (1) Add 70 parts of red lead powder, 35 parts of 4BS seed crystals, and 10 parts of SnO2-rare earth mixture (SnO2-rare earth mixture is a mixture of SnO2 and Ce elements, wherein the molar ratio of Ce to Sn is 1:9) into a high-energy ball mill. Load hard grinding balls (zirconia and tungsten carbide in a mass ratio of 1:1) into the ball mill jar. The mass ratio of the added powder to the hard grinding balls is 1:10.

[0077] (2) Inert gas—argon—is introduced into the ball mill jar to prevent the powder material from being oxidized during the grinding process.

[0078] (3) Set the rotation speed (800 rpm) and grinding time (25 hours), and run intermittently to avoid overheating.

[0079] (4) After grinding, the grinding balls are separated by sieving, and the nano powder is sieved at the same time (sieve aperture is 60nm) to obtain pretreated nano-level additive A.

[0080] 2. Additive B component water emulsification treatment

[0081] Add 30 parts of composite carbon material (carbon nanotubes: graphene: expanded graphite mass ratio = 1:2:3) and 40 parts of deionized water to an ultrasonic emulsifier, stir at low speed for 30 minutes to fully wet the material, then add 25 parts of sulfonated polyaniline binder, increase the shear speed of the emulsifier to 2800 r / min, and emulsify for 50 minutes to obtain emulsion B.

[0082] 3. Lead paste preparation process

[0083] Add 1000 parts lead powder, 8 parts sodium perborate, 1.3 parts polyester fiber, and premixed additive A to the paste mixer and start the dry mixing machine for 5 minutes. Then, spray the pretreated additive component B into the agitated lead paste in the paste mixer over 5 minutes. Next, pour in 80 parts deionized water over 3 minutes, and continue stirring for 5 minutes after the addition is complete. Then, pour in 100 parts dilute sulfuric acid over 9 minutes, and continue stirring for 13 minutes after the addition is complete. Stop the machine when the temperature drops below 45 degrees Celsius.

[0084] 4. The electrode plate adopts high-temperature curing technology. The high-temperature curing stage is at 78℃ for 9 hours and 93%RH. This ensures that sodium perborate decomposes when heated to produce oxygen, which promotes grid oxidation and further oxidation of free lead in lead paste.

[0085] Example 5

[0086] 1. Nano-scale pretreatment of additive component A:

[0087] (1) Add 80 parts of red lead powder, 40 parts of 4BS seed crystals, and 12 parts of SnO2-rare earth mixture (SnO2-rare earth mixture is a mixture of SnO2 and Ce elements, wherein the molar ratio of Ce to Sn is 1:9) into a high-energy ball mill. Load hard grinding balls (zirconia and tungsten carbide in a mass ratio of 1:1) into the ball mill jar. The mass ratio of the added powder to the hard grinding balls is 1:10.

[0088] (2) Inert gas—argon—is introduced into the ball mill jar to prevent the powder material from being oxidized during the grinding process.

[0089] (3) Set the rotation speed (1000rpm) and grinding time (30 hours), and run intermittently to avoid overheating.

[0090] (4) After grinding, the grinding balls are separated by sieving, and the nano powder is sieved at the same time (sieve aperture is 60nm) to obtain pretreated nano-level additive A.

[0091] 2. Additive B component water emulsification treatment

[0092] Add 35 parts of composite carbon material (carbon nanotubes: graphene: expanded graphite mass ratio = 1:2:3) and 40 parts of deionized water to an ultrasonic emulsifier, stir at low speed for 30 minutes to fully wet the material, then add 30 parts of sulfonated polyaniline binder, increase the shear speed of the emulsifier to 3000 r / min, and emulsify for 60 minutes to obtain emulsion B.

[0093] 3. Lead paste preparation process

[0094] Add 1000 parts lead powder, 10 parts sodium perborate, 1.5 parts polyester fiber, and premixed additive A to the paste mixer and start the dry mixing machine for 5 minutes. Then, spray the pretreated additive component B into the agitated lead paste in the paste mixer in a mist form over 5 minutes. Next, pour in 90 parts deionized water over 3 minutes, and continue stirring for 5 minutes after the addition is complete. Then, pour in 105 parts dilute sulfuric acid over 10 minutes, and continue stirring for 15 minutes after the addition is complete. Stop the machine when the temperature drops below 45 degrees Celsius.

[0095] 4. The electrode plate adopts high-temperature curing technology. The high-temperature curing stage is at 80℃ for 10 hours and 95%RH. This ensures that sodium perborate decomposes when heated to produce oxygen, which promotes grid oxidation and further oxidation of free lead in lead paste.

[0096] Comparative Example 1

[0097] 1. Nano-scale pretreatment of additive component A:

[0098] (1) Add 70 parts of red lead powder and 35 parts of 4BS seed crystals into a high-energy ball mill. Load hard grinding balls (zirconia and tungsten carbide in a mass ratio of 1:1) into the ball mill jar. The mass ratio of the added powder to the hard grinding balls is 1:10.

[0099] (2) Inert gas—argon—is introduced into the ball mill jar to prevent the powder material from being oxidized during the grinding process.

[0100] (3) Set the rotation speed (800 rpm) and grinding time (25 hours), and run intermittently to avoid overheating.

[0101] (4) After grinding, the grinding balls are separated by sieving, and the nano powder is sieved at the same time (sieve aperture 60nm) to obtain pretreated nano-level additive A.

[0102] 2. Lead paste preparation process

[0103] Add 1000 parts lead powder, 8 parts sodium perborate, 1.3 parts polyester fiber, and premixed additive A to the paste mixing machine, and start the dry mixing machine for 5 minutes. Then, pour in 120 parts deionized water over 3 minutes, and continue mixing for 5 minutes after the addition is complete. Next, pour in 100 parts dilute sulfuric acid over 9 minutes, and continue mixing for 13 minutes after the addition is complete. Stop the machine when the temperature drops below 45 degrees Celsius. 3. The electrode plate adopts high-temperature curing technology. The high-temperature curing stage is at 78 degrees Celsius for 9 hours and 93% RH to ensure that sodium perborate decomposes upon heating to generate oxygen, promoting grid oxidation and further oxidation of free lead in the lead paste.

[0104] Comparative Example 2

[0105] 1. Nano-scale pretreatment of additive component A:

[0106] (1) Add 70 parts of red lead powder and 35 parts of 4BS seed crystals into a high-energy ball mill. Load hard grinding balls (zirconia and tungsten carbide in a mass ratio of 1:1) into the ball mill jar. The mass ratio of the added powder to the hard grinding balls is 1:10.

[0107] (2) Inert gas—argon—is introduced into the ball mill jar to prevent the powder material from being oxidized during the grinding process.

[0108] (3) Set the rotation speed (800 rpm) and grinding time (25 hours), and run intermittently to avoid overheating.

[0109] (4) After grinding, the grinding balls are separated by sieving, and the nano powder is sieved at the same time (sieve aperture is 60nm) to obtain pretreated nano-level additive A.

[0110] 2. Additive B component water emulsification treatment

[0111] Add 30 parts of composite carbon material (carbon nanotubes: graphene: expanded graphite mass ratio = 1:2:3) and 40 parts of deionized water to an ultrasonic emulsifier, stir at low speed for 30 minutes to fully wet the material, then add 25 parts of sulfonated polyaniline binder, increase the shear speed of the emulsifier to 2800 r / min, and emulsify for 50 minutes to obtain emulsion B.

[0112] 3. Lead paste preparation process

[0113] Add 1000 parts lead powder, 8 parts sodium perborate, 1.3 parts polyester fiber, and premixed additive A to the paste mixer and start the dry mixing machine for 5 minutes. Then, spray the pretreated additive component B into the agitated lead paste in the paste mixer over 5 minutes. Next, pour in 80 parts deionized water over 3 minutes, and continue stirring for 5 minutes after the addition is complete. Then, pour in 100 parts dilute sulfuric acid over 9 minutes, and continue stirring for 13 minutes after the addition is complete. Stop the machine when the temperature drops below 45 degrees Celsius.

[0114] 4. The electrode plate adopts high-temperature curing technology. The high-temperature curing stage is at 78℃ for 9 hours and 93%RH. This ensures that sodium perborate decomposes when heated to produce oxygen, which promotes grid oxidation and further oxidation of free lead in lead paste.

[0115] Comparative Example 3

[0116] 1. Nano-scale pretreatment of additive component A:

[0117] (1) Add 70 parts of red lead powder, 35 parts of 4BS seed crystals and 10 parts of SnO2-rare earth mixture into a high-energy ball mill. Load hard grinding balls (zirconia and tungsten carbide in a mass ratio of 1:1) into the ball mill jar. The mass ratio of the added powder to the hard grinding balls is 1:10.

[0118] (2) Inert gas—argon—is introduced into the ball mill jar to prevent the powder material from being oxidized during the grinding process.

[0119] (3) Set the rotation speed (800 rpm) and grinding time (25 hours), and run intermittently to avoid overheating.

[0120] (4) After grinding, the grinding balls are separated by sieving, and the nano powder is sieved at the same time (sieve aperture 60nm) to obtain pretreated nano-level additive A.

[0121] 2. Lead paste preparation process

[0122] Add 1000 parts lead powder, 8 parts sodium perborate, 1.3 parts polyester fiber, and premixed additive A to the paste mixer and start the dry mixing machine for 5 minutes. Then, spray 25 parts sulfonated polyaniline binder into the agitated lead paste in the paste mixer over 5 minutes. Next, pour in 120 parts deionized water over 3 minutes, and continue stirring for 5 minutes after the addition is complete. Then, pour in 100 parts dilute sulfuric acid over 9 minutes, and continue stirring for 13 minutes after the addition is complete. Stop the machine when the temperature drops below 45 degrees Celsius.

[0123] 3. The electrode plate adopts high-temperature curing technology. The high-temperature curing stage is at 78℃ for 9 hours and 93%RH. This ensures that sodium perborate decomposes when heated to produce oxygen, which promotes grid oxidation and further oxidation of free lead in lead paste.

[0124] Comparative Example 4

[0125] 1. Nano-scale pretreatment of additive component A:

[0126] (1) Add 70 parts of red lead powder, 35 parts of 4BS seed crystals and 10 parts of SnO2-rare earth mixture into a high-energy ball mill. Load hard grinding balls (zirconia and tungsten carbide in a mass ratio of 1:1) into the ball mill jar. The mass ratio of the added powder to the hard grinding balls is 1:10.

[0127] (2) Inert gas—argon—is introduced into the ball mill jar to prevent the powder material from being oxidized during the grinding process.

[0128] (3) Set the rotation speed (800 rpm) and grinding time (25 hours), and run intermittently to avoid overheating.

[0129] (4) After grinding, the grinding balls are separated by sieving, and the nano powder is sieved at the same time (sieve aperture 60nm) to obtain pretreated nano-level additive A.

[0130] 2. Additive B component water emulsification treatment

[0131] Add 30 parts of composite carbon material (carbon nanotubes: graphene: expanded graphite mass ratio = 1:2:3) and 40 parts of deionized water into an ultrasonic emulsifier. Stir at low speed for 30 minutes to fully wet the material. Then increase the shear speed of the emulsifier to 2800 r / min and emulsify for 50 minutes to obtain emulsion B.

[0132] 3. Lead paste preparation process

[0133] Add 1000 parts lead powder, 8 parts sodium perborate, 1.3 parts polyester fiber, and premixed additive A to the paste mixer and start the dry mixing machine for 5 minutes. Then, spray the pretreated additive component B into the agitated lead paste in the paste mixer over 5 minutes. Next, pour in 80 parts deionized water over 3 minutes, and continue stirring for 5 minutes after the addition is complete. Then, pour in 100 parts dilute sulfuric acid over 9 minutes, and continue stirring for 13 minutes after the addition is complete. Stop the machine when the temperature drops below 45 degrees Celsius.

[0134] 4. The electrode plate adopts high-temperature curing technology. The high-temperature curing stage is at 78℃ for 9 hours and 93%RH. This ensures that sodium perborate decomposes when heated to produce oxygen, which promotes grid oxidation and further oxidation of free lead in lead paste.

[0135] Detection Example 1

[0136] Positive electrode plates were prepared using the positive electrode lead paste from each embodiment and comparative example, and assembled into 6-DZF-20 batteries. The test results are shown in Table 1.

[0137] (1) 2h rate discharge (room temperature capacity): According to Clause 5.5 of the national standard GB / T22199-2017 for batteries, after the battery is fully charged, it is left to stand for 1 to 24 hours in an environment with a temperature of 25±2℃. When the battery voltage is 10.5V, the 2h rate capacity Ca should reach the C2 standard within three cycles.

[0138] (2) Cycle life: According to Clause 5.12 of the national standard GB / T22199-2017 for batteries, in an environment with a temperature of 25±5℃, discharge at a current of 10A for 1.6h, and then charge at a constant voltage of 16V (current limited to 4A) for 6.4h, which is one cycle. When the battery terminal voltage drops below 10.5V for three consecutive times after discharging for 1.6h, the battery cycle life ends. The total cycle life shall not be less than 350 cycles.

[0139] Table 1

[0140] Test sample Room temperature capacity / Ah Loop count / time Battery weight / kg Specific energy (wh / kg) Example 1 21.8 410 6.05 43.24 Example 2 21.9 411 6.06 43.37 Example 3 22.1 413 6.05 43.83 Example 4 22.2 426 6.06 43.96 Example 5 22.9 438 6.06 45.34 Comparative Example 1 20.1 360 6.05 39.87 Comparative Example 2 21.9 412 6.05 43.44 Comparative Example 3 21.6 406 6.06 42.77 Comparative Example 4 21.7 418 6.05 43.04

[0141] The data above shows that adding quaternary carbon materials (carbon nanotubes, graphene, expanded graphite, and sulfonated polyaniline) can promote capacity and lifetime improvement. Adding rare earth element-SnO2 can prevent the active material from agglomerating or detaching during cycling, maintaining the porous structure of the electrode and improving charging efficiency. Changes in the ratio of rare earth elements to SnO2, within a certain range, have no significant impact on performance. Adding a mixture of quaternary carbon materials and rare earth-SnO2 can increase specific energy by 10%, lifetime by 20%, and capacity by 10%.

Claims

1. A rare earth-carbon based composite lead-acid battery positive electrode additive formulation characterized in that, By weight, it includes: 25-35 parts of carbon material, wherein the carbon material includes carbon nanotubes, graphene and expanded graphite; 20-30 parts of adhesive, wherein the adhesive is sulfonated polyaniline; 8-12 parts of SnO2-rare earth mixture, wherein rare earth includes Ce element, and the molar ratio of Ce element to Sn element is 1:8-10; 30-40 parts of 4BS seed crystals; 50-80 parts of nano red lead powder; 1 to 1.5 parts polyester fiber; Sodium perborate, 5-10 parts.

2. The rare earth-carbon based composite lead-acid battery cathode additive formulation according to claim 1, characterized in that, The mass ratio of the carbon nanotubes, graphene, and expanded graphite is 1:2:

3.

3. A method for preparing lead paste for the positive electrode of a lead-acid battery, characterized in that, The raw materials for preparing the positive electrode lead paste for lead-acid batteries include lead powder, dilute sulfuric acid, water, and each material in the rare earth-carbon-based composite lead-acid battery positive electrode additive formulation as described in any one of claims 1 to 2; The mass ratio of lead powder and carbon material in the rare earth-carbon-based composite lead-acid battery cathode additive formulation is 1000:25~35; The preparation method includes the following steps: (1) The red lead powder, 4BS seed crystals and SnO2-rare earth mixture of the formula amount were ball-milled and mixed in an inert gas atmosphere, and the nano-sized powder was obtained by sieving to prepare pre-additive A. (2) Mix and emulsify the carbon material, binder and water in the specified amounts to obtain emulsion B; (3) Dry mix the lead powder, sodium perborate, polyester fiber and pre-made additive A according to the formula, then add emulsion B and water, mix evenly, then add dilute sulfuric acid, mix evenly and then make paste.

4. The method for preparing lead paste for the positive electrode of a lead-acid battery according to claim 3, characterized in that, In the raw materials for preparing the positive electrode lead paste for lead-acid batteries, by mass, every 1000 parts of lead powder corresponds to 90-105 parts of dilute sulfuric acid, and every 1000 parts of lead powder corresponds to 110-130 parts of water.

5. The method for preparing lead paste for the positive electrode of a lead-acid battery according to claim 3, characterized in that, In step (1), the ball milling is carried out in a ball mill, and hard grinding balls are also added to the ball mill. The mass ratio of the hard grinding balls to the added raw materials is 10:

1. The ball mill rotates at 500-1000 rpm, and the milling time is 20-30 hours. The sieve used for sieving has an aperture of 60 nm.

6. The method for preparing lead paste for the positive electrode of a lead-acid battery according to claim 3, characterized in that, In step (2), an ultrasonic emulsifier is used for mixing and emulsification. The shearing speed of the ultrasonic emulsifier during mixing and emulsification is 2500~3000 r / min, and the mixing and emulsification time is 45~60 min.

7. The method for preparing lead paste for the positive electrode of a lead-acid battery according to claim 3, characterized in that, In step (3), the temperature of the ointment should not exceed 45℃.

8. A positive electrode paste for lead-acid batteries, characterized in that, It is prepared using the method for preparing lead-acid battery positive electrode paste according to any one of claims 3 to 7.

9. A lead-acid battery, comprising a positive electrode plate, characterized in that, The positive electrode plate is prepared by coating the positive electrode lead paste of the lead-acid battery as described in claim 8 onto the positive electrode plate grid and then curing it at high temperature. The high temperature curing temperature is 75~80℃, the time is 8~10 hours, and the ambient humidity is controlled within the range of 90%~95% relative humidity.