A positive electrode paste, positive electrode plate, and battery of a lead-acid battery.

Abstract

This invention discloses a positive electrode paste, a positive electrode plate, and a lead-acid battery, relating to the field of lead-acid battery technology. This invention effectively suppresses the problem of rapid battery capacity decay and improves the charge / discharge capability of the battery's positive electrode by adding a composite stabilizer, aminosulfonic acid powder, as a special additive to the lead powder in the positive electrode formulation. The composite stabilizer, aminosulfonic acid powder, includes aminosulfonic acid powder and carbon aerogel. This formulation is suitable for use in lead-acid valve-regulated electric vehicle power batteries. The positive electrode plate made with this lead paste, in performance tests of finished batteries made with the same lead paste, shows an increase in battery charge / discharge efficiency of over 2% and an increase in battery cycle life of over 28%.

Description

Technical Field

[0001] This invention relates to the field of lead-acid battery technology, and in particular to a positive electrode paste, a positive electrode plate, and a lead-acid battery. Background Technology

[0002] Since its invention in 1859, the lead-acid battery has undergone 160 years of development. Despite challenges from newer secondary power sources, lead-acid batteries still maintain a place in the secondary power market due to their excellent safety, low manufacturing cost, and near 100% recyclability. However, their short lifespan and low specific energy remain significant disadvantages.

[0003] The positive and negative plates are crucial components of a battery, directly determining its discharge capacity and cycle life. The positive electrode of a lead-acid battery consists of grids and PbO2 (lead dioxide) particles. During discharge, the lead dioxide undergoes a reduction reaction to become lead sulfate. The efficiency of this conversion process, which affects the battery's performance and quality, is primarily influenced by the lead paste formulation. Existing lead-acid battery lead pastes and their preparation methods do not meet the requirements for energy storage lead-acid batteries.

[0004] Due to the characteristics of valve-regulated lead-acid batteries, the charging and discharging capacity of electric vehicle batteries are affected by factors such as ambient temperature, usage habits, and compatible chargers. During the discharge process, valve-regulated batteries are limited by the capacity of the positive electrode plate and the electrolyte. The positive and negative electrode active materials are responsible for electrochemical conversion, and the formulation and quality of the positive electrode active materials are also necessary conditions for determining the battery capacity and cycle life.

[0005] Battery packs installed in electric vehicles on the market are often in a state of shallow charging and discharging for a long time due to riders' usage habits, such as frequent short-term charging and riding. In addition, factors such as the charging and discharging environment of electric vehicles directly affect the active material of the positive plate inside the battery, causing it to become muddy and separate. This reduces the bonding between the grid and the active material, reduces the utilization rate, and reduces the discharge characteristics, resulting in rapid capacity decay or failure, that is, shortening the life of electric vehicle batteries.

[0006] To address the aforementioned issues, manufacturers conducted market research to investigate this common practice in the electric vehicle battery market. Their focus was on resolving the problem of frequent shallow charging and discharging, which leads to passivation of the active material interface on the positive electrode plate and further deteriorates into defects such as active material sludge shedding. They optimized the positive electrode paste formulation and improved material processing to enhance the sustained effectiveness of the battery plates and extend battery life. Improving the positive electrode lead paste formulation proved to be even more effective, thereby enhancing the market competitiveness of the manufacturers' products.

[0007] Patent application CN113394400A discloses a negative electrode paste, a negative electrode plate, and a lead-acid battery, belonging to the field of lead-acid battery technology. The negative electrode paste for a lead-acid battery includes lead powder and additives. The additives include the following components: barium sulfate 0.9–1 wt%, acetylene black 0.3–0.4 wt%, lignin 0.05–0.08 wt%, humic acid 0.5–0.8 wt%, short fibers 0.07–0.08 wt%, nano-silica sol 0.03–0.05 wt%, and aminosulfonic acid 0.55–0.7 wt%, based on the total mass of lead powder. The aminosulfonic acid added to the negative electrode paste increases the sulfate content, preventing sulfation in the lead-acid battery and preventing dendrite formation; the synergistic effect of aminosulfonic acid and acetylene black helps to improve the service life of the lead-acid battery. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a positive electrode paste, a positive electrode plate, and a lead-acid battery, suitable for use in valve-regulated deep-cycle power batteries. The composite stabilizer aminosulfonic acid powder added to the positive electrode paste in this solution has high conductivity, strong binding force, low expansion rate, and high temperature resistance, and plays a certain role in preventing premature mudding and decomposition of active materials in the later stages of battery life, as well as inhibiting the shedding of active materials.

[0009] The specific technical solution of the present invention is as follows:

[0010] This invention provides a positive electrode lead paste for lead-acid batteries, comprising lead powder and additives. Based on 100 parts by weight of lead powder, the additives contain the following raw materials in parts by weight:

[0011] The composite stabilizer contains 0.02–0.04 parts of aminosulfonic acid, 0.07–0.09 parts of short fiber, 0.2–0.3 parts of colloidal graphite, 0.1–0.15 parts of antimony trioxide, and 0.05–0.06 parts of stannous sulfate.

[0012] Among them, the composite stabilizer aminosulfonic acid powder includes aminosulfonic acid powder and carbon aerogel.

[0013] The addition of stannous sulfate to the positive electrode paste can reduce the contact resistance between the grid and the active material, reduce the internal resistance of the lead-acid battery, and improve the charging and discharging efficiency of the lead-acid battery.

[0014] Preferably, the mass ratio of the aminosulfonic acid powder to the carbon aerogel is 1:0.2-0.5. The particle size after mixing is 10-15 μm, and the particle size of the aminosulfonic acid is 8-12 μm. In certain applications, the use of composite aminosulfonic acid powder, combining two different molecular structures and shapes, produces a more advantageous conductivity.

[0015] Based on 100 parts by weight of lead powder, the lead-acid battery positive electrode paste also includes 11.5 to 12.5 parts of pure water and 85 to 88 parts of sulfuric acid solution with a concentration of 1.40 g / mL.

[0016] The present invention also provides a method for preparing the positive electrode lead paste of the lead-acid battery, comprising the following steps:

[0017] (1) Lead powder, composite stabilizer aminosulfonic acid powder, short fiber, colloidal graphite, antimony trioxide and stannous sulfate are dry mixed to obtain a mixed dry powder.

[0018] (2) Add pure water to the mixed dry powder obtained in step (1) for wet mixing, and then add sulfuric acid solution to obtain the lead-acid battery positive electrode paste.

[0019] Specifically, the preparation method of the composite stabilizer aminosulfonic acid powder mentioned in step (1) is as follows:

[0020] S1: Preparation of aminosulfonic acid powder:

[0021] A sulfamic acid solution was prepared by adding aminosulfonic acid crystals to pure water; the aminosulfonic acid solution was sprayed and recrystallized to obtain aminosulfonic acid powder.

[0022] S2: Pre-treat the carbon aerogel to obtain the pre-treated carbon aerogel;

[0023] S3: The aminosulfonic acid granules obtained in step S1 and the carbon aerogel pretreated in step S2 are mixed at a mass ratio of 1:0.2 to 0.5 to obtain a mixed powder, namely the composite stabilizer aminosulfonic acid powder.

[0024] In this invention, the addition of a composite stabilizer, aminosulfonic acid powder, to the additive enables dynamic equilibrium particle exchange between the gel region in the positive electrode active material and the electrolyte, forming a macroporous aggregate framework, preventing the hydrolysis of the hydration polymerization chain, and simultaneously preventing a decrease in the density of the active material.

[0025] In step S1, the mass ratio of aminosulfonic acid crystals to pure water is 1:1; the particle size of the aminosulfonic acid powder obtained by recrystallization is 8-12 μm; the impurities are iron (Fe content ≤ 0.005%) and chlorine (Cl content ≤ 0.005%). The particle size of the composite stabilizer aminosulfonic acid powder is 10-15 μm.

[0026] Specifically, in step S1, the spraying conditions are: spraying at a temperature of 80-90℃ and a flow rate of 1.0L / min; in step S2, the pretreatment conditions are: refrigerating at 5℃ for 8 hours and controlling the humidity at 30%RH.

[0027] Pretreated carbon aerogel is more likely to combine with active materials. It has a porous structure with extremely low density, higher adsorption capacity, and can reduce battery internal resistance and enhance active materials.

[0028] Technical requirements for aminosulfonic acid crystals (NH2SO3H):

[0029] Appearance: Colorless or white crystals, soluble in water, solubility in water: 146.8 g / L (20℃);

[0030] Density: 2.126 g / cm³ 3 ;

[0031] Melting point: 205~260℃;

[0032] The molecular weight of aminosulfonic acid is 97.09;

[0033] Water-insoluble matter ≤0.02%;

[0034] Sulfate content ≤ 0.4%;

[0035] Iron (Fe) content ≤ 0.01%;

[0036] Loss on drying ≤0.2%.

[0037] Carbon aerogel technology requirements:

[0038] Porous structure with high specific surface area and extremely low density;

[0039] High elasticity, strong adsorption, and high conductivity (25-100 S / cm).

[0040] Specifically, the time for adding sulfuric acid solution in step (2) is controlled at 14-16 minutes; the apparent specific gravity of the lead-acid battery positive electrode paste is 4.44-4.48 g / cm³. 3 .

[0041] The present invention also provides a positive electrode plate for a lead-acid battery, comprising positive electrode paste, wherein the positive electrode paste is the positive electrode paste of the lead-acid battery.

[0042] The present invention also provides a lead-acid battery, including a positive electrode plate, wherein the positive electrode plate is the aforementioned positive electrode plate.

[0043] Due to the common habits of cyclists, lead-acid batteries are frequently shallow-charged and shallow-discharged, meaning they are used before being fully charged. This causes a shallow reaction between the active material layer of the positive plate and the grid interface. Over a long period of time, this reaction leads to the formation of inert substances at the grid interface, which affects the charge and discharge acceptance of the positive plate, reduces the battery capacity, and shortens the lifespan of the lead-acid battery.

[0044] Compared with the prior art, the present invention has the following advantages:

[0045] This invention effectively suppresses the problem of rapid battery capacity decay and improves the charge / discharge capability of the battery's positive electrode by adding a composite stabilizer, aminosulfonic acid powder, as a special additive to the lead powder in the positive electrode formulation. This formulation is suitable for use in lead-acid valve-regulated electric vehicle power batteries. The positive electrode plate made with this lead paste, in performance tests of finished batteries made with the same lead paste, shows improved battery conductivity, bonding strength, and high-temperature resistance. It also has a certain inhibitory effect on preventing premature mudding and decomposition of active materials and the shedding of active materials in the later stages of battery life. The high-current discharge efficiency of the battery is increased by more than 12%, and the battery cycle life is increased by more than 28%. Attached Figure Description

[0046] Figure 1 The graphs are from the battery cycle life test in Examples 3-5.

[0047] Figure 2 The graphs show the cycle life test results for Comparative Examples 1-3.

[0048] Figure 3 This is a SEM image of the electrode plate after the lead paste of Example 5 has been cured.

[0049] Figure 4 This is a SEM image of the surface of the matured electrode plate after the lead paste formulation of Example 5 is formed.

[0050] Figure 5 This is a SEM image of the inner layer of the mature electrode plate prepared with lead paste according to Example 5. Detailed Implementation

[0051] Example 1

[0052] Prepare the composite stabilizer aminosulfonic acid powder.

[0053] (1) Soak and dissolve the raw material aminosulfonic acid crystals in pure water (conductivity 100-200 S / m). The mass ratio of raw material to water is 1:1. Stir for 20 minutes and let stand for 10 minutes to precipitate, and filter out the impurities.

[0054] (2) Spray the dissolved and filtered solution in a constant temperature rotating vessel heated to 80±2℃, with the flow rate controlled at 1.0L / min, to form secondary crystallized particles; control the particle size to be 8~12μm (1000~1250 mesh sieve) white powder, which is aminosulfonic acid crystal powder.

[0055] (3) Pre-treatment of finished carbon aerogel: refrigerate at 5°C for 8 hours in a low-temperature environment and control the humidity at 30%RH to make the carbon aerogel have a more stable molecular structure and prepare it into conductive polymer carbon aerogel.

[0056] (4) Mix the secondary crystallized aminosulfonic acid granules and carbon aerogel at a mass ratio of 1:0.2 to obtain a mixed powder with a particle size of 10-15 μm (sieved through 800-1000 mesh), thus obtaining the composite stabilizer aminosulfonic acid powder.

[0057] Example 2

[0058] Prepare the composite stabilizer aminosulfonic acid powder.

[0059] (1) Soak and dissolve the raw material aminosulfonic acid crystals in pure water (conductivity 100-200 S / m). The ratio of raw material to water is 1:1. Stir for 20 minutes and let stand for 10 minutes to precipitate, and filter out the impurities.

[0060] (2) Spray the dissolved and filtered solution in a constant temperature rotating vessel heated to 80±2℃, with the flow rate controlled at 1.0L / min, to form secondary crystallized particles; control the particle size to be 8~12μm (1000~1250 mesh sieve) white powder, which is aminosulfonic acid crystal powder.

[0061] (3) Pre-treatment of finished carbon aerogel: refrigerate at 5°C for 8 hours in a low-temperature environment and control the humidity at 30%RH to make the carbon aerogel have a more stable molecular structure and prepare it into conductive polymer carbon aerogel.

[0062] (4) Mix the secondary crystallized aminosulfonic acid granules and carbon aerogel at a mass ratio of 1:0.5 to obtain a mixed powder with a particle size of 10-15 μm (sieved through 800-1000 mesh), thus obtaining the composite stabilizer aminosulfonic acid powder.

[0063] Example 3

[0064] To every 1000 kg of lead powder, add 0.2 kg of the composite stabilizer aminosulfonic acid powder prepared in Example 1, 0.7 kg of short fibers, 2 kg of colloidal graphite, 1 kg of antimony trioxide, and 0.5 kg of stannous sulfate. Dry mix for 8 minutes, add 115 kg of pure water within 1 minute and stir for 6 minutes. Then, add 85 kg of sulfuric acid with a specific gravity of 1.40 g / mL within 14 minutes and mix. Prepare a separate amount of pure water to adjust the specific gravity of the resulting lead paste to be controlled at 4.44–4.45 g / mL.

[0065] Example 4

[0066] To every 1000 kg of lead powder, add 0.3 kg of the composite stabilizer aminosulfonic acid powder prepared in Example 1, 0.8 kg of short fibers, 3 kg of colloidal graphite, 1 kg of antimony trioxide, and 0.5 kg of stannous sulfate. Dry mix for 8 minutes, then add 120 kg of pure water within 1 minute and stir for 6 minutes. Finally, add 86 kg of sulfuric acid with a specific gravity of 1.40 g / mL within 14 minutes and mix. Prepare a separate amount of pure water to adjust the specific gravity of the resulting lead paste to be controlled at 4.45–4.46 g / mL.

[0067] Example 5

[0068] To every 1000 kg of lead powder, add 0.4 kg of the composite stabilizer aminosulfonic acid powder prepared in Example 1, 0.9 kg of short fibers, 2 kg of colloidal graphite, 1.5 kg of antimony trioxide, and 0.6 kg of stannous sulfate. Dry mix for 8 minutes, add 125 kg of pure water within 1 minute and stir for 6 minutes. Then, add 88 kg of sulfuric acid with a specific gravity of 1.40 g / mL within 14 minutes and mix. Prepare a separate amount of pure water to adjust the specific gravity of the resulting lead paste to be controlled at 4.46–4.48 g / mL.

[0069] Comparative Example 1

[0070] To every 1000 kg of lead powder, add 0.7 kg of short fiber, 2 kg of colloidal graphite, 1 kg of antimony trioxide, and 0.5 kg of stannous sulfate. Dry mix for 6 minutes, then add 115 kg of pure water within 1 minute and stir for another 6 minutes. Finally, add 88 kg of sulfuric acid (specific gravity 1.40 g / mL) within 12 minutes and mix thoroughly. Prepare a separate amount of pure water to adjust the specific gravity of the resulting lead paste to be between 4.44 and 4.45 g / mL.

[0071] Comparative Example 2

[0072] To every 1000 kg of lead powder, add 0.8 kg of short fiber, 2 kg of colloidal graphite, 1 kg of antimony trioxide, and 0.5 kg of stannous sulfate. Dry mix for 7 minutes, then add 120 kg of pure water within 1 minute and stir for another 7 minutes. Finally, add 87 kg of sulfuric acid (specific gravity 1.40 g / mL) within 13 minutes and mix thoroughly. Prepare a separate amount of pure water to adjust the specific gravity of the resulting lead paste to be controlled between 4.45 and 4.46 g / mL.

[0073] Comparative Example 3

[0074] To every 1000 kg of lead powder, add 0.9 kg of short fiber, 2 kg of colloidal graphite, 1 kg of antimony trioxide, and 0.5 kg of stannous sulfate. Dry mix for 8 minutes, then add 125 kg of pure water within 1 minute and stir for another 8 minutes. Finally, add 85 kg of sulfuric acid (specific gravity 1.40 g / mL) within 14 minutes and mix thoroughly. Prepare a separate amount of pure water to adjust the specific gravity of the resulting lead paste to be between 4.46 and 4.48 g / mL.

[0075] Test Example 1

[0076] The positive electrode paste formulations from Examples 3-5 and Comparative Examples 1-3 were applied to the positive electrode grid of a 6-DZF-35 lead-acid battery. The battery underwent a drying process at 150°C and a speed of 30 pcs / min. The curing and drying process is shown in Table 1. After edge finishing, a positive electrode green plate was obtained, which was then used to manufacture finished batteries in conjunction with negative electrode plates from the same batch of 6-DZF-35 batteries. The SEM image of the cured positive electrode green plate from Example 5 is shown below. Figure 3 As shown, observations revealed that the PbO2 grain structure was more compact after high-temperature and high-humidity curing, which is beneficial for the bonding of the grid and the positive electrode active material. Subsequently, the surface of the cured positive electrode plate after formation was scanned using an electron microscope, revealing... Figure 4 It can be seen that a dense protective layer of lead sulfate (PbSO4) forms on the surface of the electrode plate, which can reduce the expansion and loosening of the active material in the later stage; after formation, the mature positive electrode plate is peeled off and the inner layer is scanned with an electron microscope, from... Figure 5 It can be seen that the inner layer has a uniformly distributed active material crystal structure, which can improve the discharge stability of the battery's positive electrode.

[0077] High-current discharge efficiency test: One sample of each of the batteries in Examples 3, 4, 5 and Comparative Examples 1, 2, 3 was taken and placed in a laboratory environment at 25±2℃ for 1h to 4h. The batteries were then discharged at 3.6I2(A) until the battery terminal voltage was 1.75V / cell. The discharge time was recorded, with a standard of >25min.

[0078] Four discharge capacity tests: One sample of each of the batteries in Examples 3, 4, and 5 and Comparative Examples 1, 2, and 3 was taken. In a laboratory environment of 25±2℃, the batteries were discharged at IC317.5A to the termination voltage of 1.75V / cell, and then charged at 17A with a charging limit of 59.6V / group for 4 hours. Four cycles of capacity discharge tests were performed, the discharge time was recorded, and the actual discharge capacity of the batteries was calculated. The standard is ≥35Ah.

[0079] Cycle life test: One set of four 48V / 35Ah battery packs was sampled from both the example and comparative batteries for cycle life testing. The test conditions were rapid cycle test: charging at 17A with a charging voltage limit of 59.6V / pack for 4 hours; discharging at 17.5A with a discharge termination voltage limit of 42V / pack. The battery packs were placed in a constant temperature water bath with a cooling water temperature of 25±2℃.

[0080] Battery performance test data are shown in Tables 2 and 3, and the cycle life test results are as follows: Figure 1 and Figure 2 As shown.

[0081] Table 1

[0082]

[0083] Table 2 Battery performance test results for examples

[0084]

[0085] Table 3 Comparative Battery Performance Tests

[0086]

[0087] As shown in Table 2, the average maximum capacity of the batteries prepared in Examples 3-5 during the third discharge was 36.9 Ah; the high-current discharge time was 28 minutes for all examples. As shown in Table 3, the average maximum capacity of the batteries prepared in Comparative Examples 1-3 was 35.5 Ah; the high-current discharge time was 25 minutes for all examples. The comparison shows that the lead-acid battery formulated in this invention has an increased capacity of approximately 4.0% and an increased high-current discharge capability of 12%. Figure 1 and Figure 2 The results show that the cycle life of the example battery was extended by approximately 98 cycles compared to the comparative battery, representing a 28% improvement.

Claims

1. A positive electrode paste for a lead-acid battery, comprising lead powder and additives, characterized in that, Based on 100 parts by weight of lead powder, the additive comprises the following raw materials in parts by weight: The composite stabilizer contains 0.02–0.04 parts of aminosulfonic acid, 0.07–0.09 parts of short fiber, 0.2–0.3 parts of colloidal graphite, 0.1–0.15 parts of antimony trioxide, and 0.05–0.06 parts of stannous sulfate. Among them, the composite stabilizer aminosulfonic acid powder includes aminosulfonic acid powder and carbon aerogel; The mass ratio of aminosulfonic acid powder to carbon aerogel is 1:0.2-0.5, wherein the particle size of aminosulfonic acid powder is 8-12 μm; and the particle size of the composite stabilizer aminosulfonic acid powder is 10-15 μm. The carbon aerogel is a pretreated carbon aerogel. The pretreatment conditions are: refrigeration at 5°C for 8 hours and humidity control at 30%RH.

2. The positive electrode lead paste of the lead-acid battery as described in claim 1, characterized in that, Based on 100 parts by weight of lead powder, the lead-acid battery positive electrode paste also includes 11.5 to 12.5 parts of pure water and 85 to 88 parts of sulfuric acid solution with a density of 1.40 g / mL.

3. The method for preparing the positive electrode lead paste of the lead-acid battery according to claim 1 or 2, characterized in that, Includes the following steps: (1) Lead powder, composite stabilizer aminosulfonic acid powder, short fiber, colloidal graphite, antimony trioxide and stannous sulfate are dry mixed to obtain a mixed dry powder; (2) Add pure water to the mixed dry powder obtained in step (1) for wet mixing, and then add sulfuric acid solution to obtain the lead-acid battery positive electrode paste.

4. The preparation method according to claim 3, characterized in that, The preparation method of the composite stabilizer aminosulfonic acid powder mentioned in step (1) is as follows: S1: Preparation of aminosulfonic acid powder: A sulfamic acid solution was prepared by adding aminosulfonic acid crystals to pure water; the aminosulfonic acid solution was sprayed and recrystallized to obtain aminosulfonic acid powder; the particle size of the recrystallized aminosulfonic acid powder was 8-12 μm; the particle size of the composite stabilizer aminosulfonic acid powder was 10-15 μm. S2: Pre-treat the carbon aerogel to obtain the pre-treated carbon aerogel; the pre-treatment conditions are: refrigerate at 5℃ for 8 hours and control the humidity at 30%RH. S3: The aminosulfonic acid granules obtained in step S1 and the carbon aerogel pretreated in step S2 are mixed at a mass ratio of 1:0.2 to 0.5 to obtain a mixed powder, namely the composite stabilizer aminosulfonic acid powder.

5. The preparation method according to claim 4, characterized in that, In step S1, the mass ratio of aminosulfonic acid crystals to pure water is 1:

1.

6. The preparation method according to claim 4, characterized in that, In step S1, the spraying conditions are: spraying is carried out at a temperature of 80-90℃ and a flow rate of 1.0L / min.

7. The preparation method according to claim 3, characterized in that, The time for adding sulfuric acid solution in step (2) is controlled at 14-16 minutes; the apparent specific gravity of the lead-acid battery positive electrode paste is 4.44-4.48 g / cm³. 3 .

8. A positive electrode plate for a lead-acid battery, comprising positive electrode lead paste, characterized in that, The positive electrode paste is the positive electrode paste of the lead-acid battery as described in claim 1 or 2.

9. A lead-acid battery, comprising a positive electrode plate, characterized in that, The positive electrode plate is the positive electrode plate as described in claim 8.

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