Positive electrode lead paste for high-capacity and long-service-life storage battery and preparation method therefor

Abstract

A positive electrode lead paste for a high-capacity and long-service-life storage battery and a preparation method therefor. The formula of the positive electrode lead paste comprises lead powder, dilute sulfuric acid, water and additives. In parts by mass, the additives added to every 1000 parts of the lead powder comprise: 1-3 parts of sodium perborate; 0.5-2 parts of 4BS; 1-3 parts of antimony trioxide; 1-3 parts of tin pyrophosphate; 2-4 parts of a polyolefin; 2-4 parts of a conductive carbon material; and 1-1.5 parts of a polyester staple fiber. By adding tin pyrophosphate and the polyolefin in the positive electrode lead paste, the capacity of a lead storage battery can be effectively increased and the service life thereof can be prolonged; and tin pyrophosphate and the polyolefin can work synergistically, and the addition of the two together achieves a better effect.

Description

A positive electrode paste for high-capacity, long-life storage batteries and its preparation method Technical Field

[0001] This invention belongs to the field of lead-acid battery technology, specifically relating to a positive electrode lead paste for high-capacity, long-life batteries and its preparation method. Background Technology

[0002] The structure of a lead-acid battery includes a battery case and electrode groups and electrolyte disposed within the battery case. The electrode groups consist of positive plates, negative plates and separators. The performance of the positive and negative plates plays a key role in the performance of the lead-acid battery.

[0003] The positive electrode plate consists of the positive electrode grid and the positive electrode lead paste. The formulation of the positive electrode lead paste plays a decisive role in the performance of the positive electrode plate. Therefore, one direction for improving the capacity and lifespan of lead-acid batteries is to improve the formulation of the positive electrode lead paste and the paste mixing process.

[0004] For example, invention application CN117855467A discloses a positive electrode paste for lead-acid batteries and its preparation method. Calcium peroxide is added to the positive electrode active material formula of the battery, which provides both oxygen to promote the continuous oxidation of free lead and the corrosion of the grid ribs to improve the bonding force with the active material, and calcium sulfate to improve the discharge performance of the battery. Simultaneously, combined with a vacuum high-temperature paste-forming process, the temperature can be controlled by reducing pressure when the lead paste temperature exceeds 85°C, thus achieving the goal of controlling the paste-forming temperature through pressure.

[0005] For example, invention application CN117936772A discloses a positive electrode lead paste formula and its preparation method for improving the cycle life and low-temperature performance of lead-acid batteries. The positive electrode lead paste formula includes lead powder, conductive ground carbon fiber powder, 4BS seed crystals, red lead, ultra-strong polyester short fibers, bamboo-like carbon nanotubes, SnSO4, Sb2O3, Bi2O3, CMC+SBR mixture, ultra-strong polyester short fibers, bamboo-like carbon nanotubes, red lead, dilute sulfuric acid, and deionized water. Without changing the existing paste preparation process, using the CMC and SBR mixture as a binder can improve the problem of positive electrode lead paste falling off during use; the addition of conductive ground carbon fiber powder and bamboo-like carbon nanotubes can replace short fibers and graphite, and can alleviate the deformation problem caused by the large volume change of PbO2 electrode during charging and discharging, thus improving the high-current discharge capability at low temperatures; antimony trioxide, 4BS seed crystals, etc., increase the cycle performance of the battery.

[0006] However, developing new positive electrode lead paste formulations is still of positive significance. Summary of the Invention

[0007] To address the aforementioned shortcomings in the prior art, this invention provides a positive electrode paste for high-capacity, long-life storage batteries and its preparation method.

[0008] This invention first provides a positive electrode lead paste for high-capacity, long-life storage 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 of sodium perborate; 0.5-2 parts of 4BS; 1-3 parts of antimony trioxide; 1-3 parts of tin pyrophosphate; 2-4 parts of polyolefin; 2-4 parts of conductive carbon material; and 1-1.5 parts of polyester short fiber.

[0009] Preferably, the dilute sulfuric acid is 90-110 parts, the density of the dilute sulfuric acid is 1.3-1.5 g / cm3, and the water is 105-130 parts.

[0010] Preferably, the polyolefin is poly4-methyl-1-pentene.

[0011] Preferably, the conductive carbon material is at least one of the following: acetylene black, graphite, graphene, fullerene, and carbon nanotubes.

[0012] This invention further provides a method for preparing the positive electrode lead paste for the high-capacity, long-life storage battery, comprising the following steps:

[0013] (1) Add the prescribed amounts of sodium perborate and tin pyrophosphate to a portion of dilute sulfuric acid and stir to dissolve to obtain auxiliary solution A;

[0014] (2) The polyolefin and conductive carbon material in the specified amounts are mixed and coated to obtain composite material B;

[0015] (3) Add the formulated amount of lead powder, 4BS, antimony trioxide, composite material B obtained in step (2), and polyester short fiber to the paste mixing machine for dry mixing; then pour water in while stirring; then pour in the auxiliary liquid A obtained in step (1) while stirring; finally pour in the remaining dilute sulfuric acid while stirring, and stir to obtain positive electrode lead paste.

[0016] Preferably, in step (1), the prescribed amounts of sodium perborate and tin pyrophosphate are added to 10 parts of dilute sulfuric acid, stirred and mixed at 50-70°C for 10-20 minutes to fully dissolve, and then cooled to obtain the auxiliary solution A.

[0017] Preferably, in step (2), polyolefin and conductive carbon material are added into a nano-resonance coating machine for resonance coating for 60-90 minutes to obtain composite material B.

[0018] The present invention also provides a positive electrode plate for a storage battery, comprising positive electrode paste, wherein the positive electrode paste is the same as the positive electrode paste for high-capacity, long-life storage batteries.

[0019] Adding trace amounts of sodium perborate to the positive electrode lead paste improves the crystal structure of the active material, significantly enhancing the paste's viscosity and permeability. This also increases the bonding force between active materials, resulting in more uniform crystal sizes, which improves electron transport quality and battery consistency.

[0020] Sodium perborate reacts during the paste preparation process to generate hydrogen peroxide and sodium borate. After ionization, hydrogen peroxide increases the oxygen ion content in the lead paste. The strong oxidizing property of hydrogen peroxide helps to accelerate and improve the oxidation degree of lead powder, reduce curing time, and help form a stable conductive network structure of active material, thereby improving the positive electrode's charge acceptance capacity. At the same time, due to the increased deep oxidation, the bonding force between the active material and the grid is also enhanced. During the charge and discharge reaction of the electrode plate, the bonding force of the active material is strengthened, ensuring that the active material does not loosen, soften, or fall off.

[0021] Adding 4BS seeds to positive electrode lead paste has the following advantages:

[0022] 1. It lowers the barrier to conversion from 3BS to 4BS, thereby reducing the curing temperature and shortening the curing time;

[0023] 2. Because the active material grows on the 4BS seed crystals during the reaction process, the 4BS grains are evenly distributed after curing, and the grain size is relatively uniform, resulting in good plate consistency.

[0024] 3. 4BS crystals are abundant and have high porosity of active materials.

[0025] After 4BS is added to the positive electrode lead paste, the 4BS crystals continue to grow to over 10μm in size after curing, and their quantity is abundant. This provides a more stable framework and increases the active area, which is beneficial for improving the positive electrode plate's resistance to softening and preventing high-rate charge-discharge softening failure (PCL-2) of the lead-acid battery positive electrode plate. It also increases the battery's specific energy. Positive electrode plates with added 4BS seed crystals exhibit excellent cycle stability, and the utilization rate of active materials is higher than that of ordinary positive electrode plates.

[0026] The conductive carbon material used in this invention is a nanoscale carbon material such as acetylene black, graphite, graphene, fullerene, or carbon nanotubes. Adding conductive carbon material to the positive electrode paste reduces electrode resistance, improves the conductivity of the paste, promotes the formation of α-PbO2 after formation, and also increases the porosity and roughness of the active material. When added to the battery, the conductive carbon material undergoes an oxidation reaction on the surface of the positive electrode plate during charging. The addition of conductive carbon material increases the porosity of the active material in the positive electrode plate, thereby improving the utilization rate of the active material.

[0027] The antimony in antimony trioxide added to the positive electrode lead paste acts as a PbO2 nucleating agent, increasing the initial capacity of the positive electrode plate. At the same time, the presence of antimony changes the corrosion layer formation mechanism, which not only prevents the active material from falling off the grid, but also effectively prevents the formation of a passivation layer between the lead-calcium alloy grid and the active material, preventing early capacity decay of the battery, increasing the battery's service life, reducing the battery's internal resistance, and improving the grid's corrosion resistance.

[0028] Tin pyrophosphate (also known as stannous pyrophosphate) is a white crystalline or amorphous powder, insoluble in water, but slowly dissolves in dilute acid. Therefore, tin pyrophosphate is dispersed in dilute sulfuric acid before use. During the reaction, tin pyrophosphate slowly decomposes into phosphate ions and tin ions. In this invention, by adding tin pyrophosphate to the positive electrode lead paste, the low solubility of tin pyrophosphate in dilute sulfuric acid ensures a constant presence of phosphate and tin ions in the electrolyte. Phosphate ions can slow down the softening and shedding of the positive electrode active material, thereby improving the electrode plate lifespan. Phosphate ions can reduce the content of PbSO4 and PbO2 in the corrosion film and increase the PbO content, effectively reducing the softening and shedding of the active material during charging and discharging, inhibiting sulfation, reducing grid alloy corrosion, and improving the positive electrode lifespan. Positive electrode active materials containing tin-based additives can almost completely restore the lead sulfate produced during discharge to lead dioxide after charging, thereby reducing the shedding of positive electrode active materials during charge and discharge reactions, significantly improving charge and discharge cycle performance, and thus extending lifespan.

[0029] Polyolefins are structural conductive polymers with an average particle size of 150 μm and a porous structure. When added to lead paste, they increase the porosity of PAM and the battery discharge rate. After being doped with highly conductive carbon materials, the conductivity of polyolefin polymers is greatly improved, reaching the conductivity level of metals. Adding polyolefin / conductive carbon composite materials can effectively improve the conductivity of active materials, thereby improving the deep discharge performance and charge acceptance of the battery.

[0030] After being resonantly coated with highly conductive materials, polyolefins can form a porous system in lead paste, improving the utilization rate of active materials and thus increasing the electrode capacity. At the same time, polyolefins also act as a binder in lead paste, delaying the softening and shedding time of active materials, thereby improving the cycle life of active materials.

[0031] This invention effectively improves the capacity and lifespan of lead-acid batteries by adding tin pyrophosphate and polyolefin to the positive electrode lead paste. Furthermore, the two work synergistically, and adding them together yields even better results. Detailed Implementation

[0032] In the following examples, the number of parts specified in the ingredient addition amount are all by weight.

[0033] Example 1

[0034] In this embodiment, the density of the dilute sulfuric acid solution is 1.3 g / cm³. 3 The process of preparing the positive electrode lead paste in this embodiment is as follows:

[0035] (1) Preparation of auxiliary acid solution

[0036] Add 1 part sodium perborate and 1 part tin pyrophosphate to 10 parts dilute sulfuric acid solution, stir and mix at 50°C for 10 minutes until fully dissolved, cool to room temperature and use to obtain auxiliary solution A.

[0037] (2) Coating and mixing

[0038] Two parts of nanoporous polyolefin and two parts of conductive carbon material (acetylene black) were added into a nano-resonance coating machine and subjected to resonance coating and doping at room temperature for 60 minutes to obtain nanoporous polyolefin / conductive carbon material composite material B.

[0039] (3) Paste preparation process

[0040] 1000 parts of lead powder were placed into a paste-making machine, followed by 0.5 parts of 4BS, 1 part of antimony trioxide, the prepared composite material B, and 1 part of polyester short fiber. The paste-making machine was then sealed and dry-stirred for 3 minutes. Then, 105 parts of pure water were poured in over 5 minutes, with continuous stirring during the pouring process. After the pouring was completed, stirring was continued for another 5 minutes. Then, auxiliary liquid A was poured in over 2 minutes, with continuous stirring during the pouring process. Next, 80 parts of dilute sulfuric acid were poured in over 10 minutes, with the cooling circulating water machine and cooling fan turned on during the pouring process. After the pouring was completed, stirring was continued for 10 minutes before the machine was stopped, thus obtaining the positive electrode lead paste.

[0041] Example 2

[0042] In this embodiment, the density of the dilute sulfuric acid solution is 1.4 g / cm³. 3 The process of preparing the positive electrode lead paste in this embodiment is as follows:

[0043] (1) Preparation of auxiliary acid solution

[0044] Add 2 parts of sodium perborate and 2 parts of tin pyrophosphate to 10 parts of dilute sulfuric acid solution, stir and mix at 60°C for 15 minutes until fully dissolved, cool to room temperature and use to obtain auxiliary solution A.

[0045] (2) Coating and mixing

[0046] Three parts of nanoporous polyolefin and three parts of conductive carbon material (acetylene black) were added to a nano-resonance coating machine and subjected to resonance coating and doping at room temperature for 75 minutes to obtain nanoporous polyolefin / conductive carbon material composite material B.

[0047] (3) Paste preparation process

[0048] 1000 parts of lead powder were placed into a paste-making machine, followed by 1 part of 4BS, 2 parts of antimony trioxide, the prepared composite material B, and 1.2 parts of polyester short fibers. The paste-making machine was then sealed and dry-stirred for 4 minutes. Then, 120 parts of pure water were poured in over 8 minutes, with continuous stirring during the pouring process. After the pouring was completed, stirring was continued for 5 minutes. Then, auxiliary liquid A was poured in over 2.5 minutes, with continuous stirring during the pouring process. Next, 90 parts of dilute sulfuric acid were poured in over 12 minutes, with the cooling circulating water machine and cooling fan turned on during the pouring process. After the pouring was completed, stirring was continued for 10 minutes before the machine was stopped, thus obtaining the positive electrode lead paste.

[0049] Example 3

[0050] In this embodiment, the density of the dilute sulfuric acid solution is 1.5 g / cm³. 3 The process of preparing the positive electrode lead paste in this embodiment is as follows:

[0051] (1) Preparation of auxiliary acid solution

[0052] Add 3 parts of sodium perborate and 3 parts of tin pyrophosphate to 10 parts of dilute sulfuric acid solution, stir and mix at 70°C for 20 minutes until fully dissolved, cool to room temperature and use to obtain auxiliary solution A.

[0053] (2) Coating and mixing

[0054] Four parts of nanoporous polyolefin and four parts of conductive carbon material (acetylene black) were added into a nano-resonance coating machine and subjected to resonance coating and doping at room temperature for 90 minutes to obtain nanoporous polyolefin / conductive carbon material composite material B.

[0055] (3) Paste preparation process

[0056] 1000 parts of lead powder were placed into a paste-making machine, followed by 2 parts of 4BS, 3 parts of antimony trioxide, the prepared composite material B, and 1.5 parts of polyester short fibers. The paste-making machine was then sealed and dry-stirred for 5 minutes. Then, 130 parts of pure water were poured in over 10 minutes, with continuous stirring during the pouring process. After the pouring was completed, stirring was continued for another 5 minutes. Then, auxiliary liquid A was poured in over 3 minutes, with continuous stirring during the pouring process. Next, 100 parts of dilute sulfuric acid were poured in over 15 minutes, with the cooling circulating water machine and cooling fan turned on during the pouring process. After the pouring was completed, stirring was continued for 10 minutes before the machine was stopped, thus obtaining the positive electrode lead paste.

[0057] Comparative Example 1

[0058] In this embodiment, the density of the dilute sulfuric acid solution is 1.4 g / cm³. 3 The process of preparing the positive electrode lead paste in this embodiment is as follows:

[0059] (1) Preparation of auxiliary acid solution

[0060] Add 2 parts of sodium perborate to 10 parts of dilute sulfuric acid solution, stir and mix at 60°C for 15 minutes until fully dissolved, cool to room temperature and use to obtain auxiliary solution A.

[0061] (2) Coating and mixing

[0062] Three parts of nanoporous polyolefin and three parts of conductive carbon material (acetylene black) were added to a nano-resonance coating machine and subjected to resonance coating and doping at room temperature for 75 minutes to obtain nanoporous polyolefin / conductive carbon material composite material B.

[0063] (3) Paste preparation process

[0064] 1000 parts of lead powder were placed into a paste-making machine, followed by 1 part of 4BS, 2 parts of antimony trioxide, the prepared composite material B, and 1.2 parts of polyester short fibers. The paste-making machine was then sealed and dry-stirred for 4 minutes. Then, 120 parts of pure water were poured in over 8 minutes, with continuous stirring during the pouring process. After the pouring was completed, stirring was continued for 5 minutes. Then, auxiliary liquid A was poured in over 2.5 minutes, with continuous stirring during the pouring process. Next, 90 parts of dilute sulfuric acid were poured in over 12 minutes, with the cooling circulating water machine and cooling fan turned on during the pouring process. After the pouring was completed, stirring was continued for 10 minutes before the machine was stopped, thus obtaining the positive electrode lead paste.

[0065] Comparative Example 2

[0066] In this embodiment, the density of the dilute sulfuric acid solution is 1.4 g / cm³. 3 The process of preparing the positive electrode lead paste in this embodiment is as follows:

[0067] (1) Preparation of auxiliary acid solution

[0068] Add 2 parts of sodium perborate and 2 parts of tin pyrophosphate to 10 parts of dilute sulfuric acid solution, stir and mix at 60°C for 15 minutes until fully dissolved, cool to room temperature and use to obtain auxiliary solution A.

[0069] (2) Paste preparation process

[0070] 1000 parts of lead powder were placed into a paste mixing machine, followed by 1 part of 4BS, 2 parts of antimony trioxide, 3 parts of conductive carbon material (acetylene black), and 1.2 parts of polyester short fiber. The paste mixing machine was then sealed and dry-stirred for 4 minutes. Then, 120 parts of pure water were poured in over 8 minutes, with continuous stirring during the pouring process. After the pouring was completed, stirring was continued for 5 minutes. Then, auxiliary liquid A was poured in over 2.5 minutes, with continuous stirring during the pouring process. Next, 90 parts of dilute sulfuric acid were poured in over 12 minutes, with the cooling circulating water machine and cooling fan turned on during the pouring process. After the pouring was completed, stirring was continued for 10 minutes before the machine was stopped to obtain the positive electrode lead paste.

[0071] Comparative Example 3

[0072] In this embodiment, the density of the dilute sulfuric acid solution is 1.4 g / cm³. 3 The process of preparing the positive electrode lead paste in this embodiment is as follows:

[0073] (1) Preparation of auxiliary acid solution

[0074] Add 2 parts of sodium perborate to 10 parts of dilute sulfuric acid solution, stir and mix at 60°C for 15 minutes until fully dissolved, cool to room temperature and use to obtain auxiliary solution A.

[0075] (2) Paste preparation process

[0076] 1000 parts of lead powder were placed into a paste mixing machine, followed by 1 part of 4BS, 2 parts of antimony trioxide, 3 parts of conductive carbon material (acetylene black), and 1.2 parts of polyester short fiber. The paste mixing machine was then sealed and dry-stirred for 4 minutes. Then, 120 parts of pure water were poured in over 8 minutes, with continuous stirring during the pouring process. After the pouring was completed, stirring was continued for 5 minutes. Then, auxiliary liquid A was poured in over 2.5 minutes, with continuous stirring during the pouring process. Next, 90 parts of dilute sulfuric acid were poured in over 12 minutes, with the cooling circulating water machine and cooling fan turned on during the pouring process. After the pouring was completed, stirring was continued for 10 minutes before the machine was stopped to obtain the positive electrode lead paste.

[0077] Detection Example 1

[0078] The positive lead paste prepared in each embodiment and comparative example was used to produce electrode plates, which were then assembled into 6-DZF-20 batteries.

[0079] (1) 2h rate discharge: According to Clause 5.5 of the national standard GB / T22199-2017 for batteries, after the battery is fully charged, it should be 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.

[0080] (2) High current discharge: Follow the provisions of GB / T22199-2017, the national standard for batteries, after the battery is fully charged, let it stand for 1 to 4 hours in an environment with a temperature of 25±5℃, and then discharge it with a current of 3.6A until the battery voltage reaches 10.5V. The discharge duration should not be less than 25 minutes.

[0081] (3) 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.

[0082] The test results are shown in Table 1.

[0083] Table 1

[0084] As shown in Table 1, the additives and additive pre-processing technology of this invention can significantly improve the room temperature capacity by about 8%, the high current discharge by about 15%, and the lifespan by about 15%.

Claims

1. A positive electrode paste for high-capacity, long-life storage batteries, comprising lead powder, dilute sulfuric acid, water, and additives, characterized in that, The additives added per 1000 parts by weight 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 staple fiber.

2. The positive electrode lead paste for high-capacity, long-life storage batteries according to claim 1, characterized in that, The dilute sulfuric acid is 90-110 parts, and the density of the dilute sulfuric acid is 1.3-1.5 g / cm3; the water is 105-130 parts.

3. The positive electrode lead paste for high-capacity, long-life storage batteries according to claim 1, characterized in that, The polyolefin is poly4-methyl-1-pentene.

4. The positive electrode lead paste for high-capacity, long-life storage batteries according to claim 1, characterized in that, The conductive carbon material is at least one of the following: acetylene black, graphite, graphene, fullerene, and carbon nanotubes.

5. The method for preparing the positive electrode lead paste for high-capacity, long-life storage batteries according to any one of claims 1 to 4, characterized in that, Includes the following steps: (1) Add the prescribed amounts of sodium perborate and tin pyrophosphate to a portion of dilute sulfuric acid and stir to dissolve to obtain auxiliary solution A; (2) The polyolefin and conductive carbon material in the specified amounts are mixed and coated to obtain composite material B; (3) Add the formulated amount of lead powder, 4BS, antimony trioxide, composite material B obtained in step (2), and polyester short fiber to the paste mixing machine for dry mixing; then pour water in while stirring; then pour in the auxiliary liquid A obtained in step (1) while stirring; finally pour in the remaining dilute sulfuric acid while stirring, and stir to obtain the positive electrode lead paste for high-capacity long-life storage batteries.

6. The method for preparing positive electrode lead paste for high-capacity, long-life storage batteries according to claim 5, characterized in that, In step (1), the prescribed amounts of sodium perborate and tin pyrophosphate are added to 10 parts of dilute sulfuric acid, stirred and mixed at 50-70°C for 10-20 minutes to fully dissolve, and then cooled to obtain the auxiliary solution A.

7. The method for preparing positive electrode lead paste for high-capacity, long-life storage batteries according to claim 5, characterized in that, In step (2), polyolefin and conductive carbon materials are added to a nano-resonance coating machine for resonance coating for 60-90 minutes to obtain composite material B.

8. A positive electrode plate for a storage battery, characterized in that, Includes positive electrode paste, wherein the positive electrode paste is the high-capacity, long-life battery positive electrode paste according to any one of claims 1 to 4.

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