A positive plate for lead-acid batteries and a lead-acid battery

Abstract

The application discloses a lead storage battery positive plate and a lead storage battery and belongs to the technical field of lead storage batteries. The lead storage battery positive plate comprises a positive plate grid and positive lead paste coated on the positive plate grid, and the composition of the positive lead paste comprises lead powder, a sulfuric acid solution, pure water and an additive; the additive comprises a magnesium fluorosilicate solution. In the process of positive formula lead powder paste preparation, pure water and the prepared magnesium fluorosilicate solution are added to the mixed dry powder for wet mixing, and then a sulfuric acid solution is added to prepare the positive lead paste of the lead storage battery. The positive plate provided by the application has the characteristics of strong active material binding force, high temperature resistance and crack resistance, can improve the conductivity, long-life cycle charging and discharging characteristics and the like of the battery, has certain inhibiting effect on preventing early mudification and decomposition of active materials and active material shedding in the later period of the battery, and the charging and discharging efficiency of the battery is improved by more than 2.2%, and the service cycle life of the battery is improved by more than 8%.

Description

Technical Field

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

[0002] Since its invention in 1859, the lead-acid battery has undergone more than 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] Positive and negative plates are crucial components of a battery. The quality of the positive plate directly determines the battery's discharge capacity and cycle life. The positive electrode of a lead-acid battery consists of grids and lead dioxide (PbO2) particles. During discharge, the lead dioxide undergoes a reduction reaction to become lead sulfate. The efficiency of this conversion process affects the battery's performance and quality, primarily influenced by the lead paste formulation. Existing lead-acid battery lead pastes and their preparation methods do not meet the requirements for power 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 matching chargers. During the discharge process, valve-regulated batteries are limited by the active material of the positive electrode plate, capacity, and electrolyte. The active materials of the positive and negative electrodes are the main materials for electrochemical conversion, and their formulation and quality are necessary conditions for determining the battery capacity and cycle life.

[0005] Battery packs installed in electric vehicles on the market are subject to various factors. Due to riders' usage habits, such as frequent short-term charging followed by riding, the battery packs are often in a state of shallow charging and discharging for extended periods. This means they are used before being fully charged. As a result, the active material layer of the positive electrode plate reacts with the surface layer of the grid interface. Over a long period of time, inert substances are formed at the grid interface with the active material. In addition, the charging and discharging environment of electric vehicles directly affects the active material of the positive electrode 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, leading to rapid capacity decay or failure, which shortens the battery life of electric vehicles.

[0006] To address the defects in electric vehicle batteries, such as passivation of the active material interface on the positive electrode plate due to frequent shallow charging and discharging, which can further evolve into active material sludge shedding, increasing the bonding strength between the grid and lead paste is an effective solution. Patent document CN 104466195A discloses a salting treatment process for lead-acid batteries. The grid is immersed in a sodium bicarbonate solution for 2 hours, then placed in a high-concentration carbon dioxide environment to salt the grid surface. This process produces a certain amount of carbonates and lead oxide on the grid surface, which react rapidly with the lead paste, enhancing the corrosion resistance of the grid during curing and increasing the bonding strength between the grid and the lead paste. In addition, optimizing the positive electrode paste formulation and improving material processing are also solutions. However, how to improve the positive electrode lead paste formulation to enhance the bonding between the grid and the active material, improve the continuous effective performance of the battery plates, and enhance the market competitiveness of the manufacturer's products are problems that those skilled in the art need to solve. Summary of the Invention

[0007] The purpose of this invention is to provide a positive plate for lead-acid batteries suitable for valve-regulated lean electrolyte long-life power batteries, in order to solve the problems of passivation of the active material interface of the positive plate caused by frequent shallow charging and discharging, which affects the charge and discharge acceptance of the positive plate, reduces the battery capacity, and shortens the service life of the lead-acid battery.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] This invention provides a positive electrode plate for a lead-acid battery, comprising a positive electrode grid and a positive electrode lead paste coated on the positive electrode grid. The positive electrode lead paste comprises lead powder, sulfuric acid solution, pure water, and additives. Based on 100 parts by weight of lead powder, the sulfuric acid solution comprises 8.2–8.8 parts; the pure water comprises 10.0–11.0 parts; the additives comprise 0.2–0.4 parts of magnesium fluorosilicate solution, 0.08–0.10 parts of short fibers, 0.3–0.4 parts of colloidal graphite, 0.01–0.2 parts of antimony trioxide, and 0.25–0.3 parts of stannous sulfate; wherein the magnesium fluorosilicate solution is prepared by dissolving magnesium fluorosilicate crystals in pure water at a mass ratio of 1:1.

[0010] This invention reduces cracking and shedding of the positive electrode active material by adding magnesium fluorosilicate to the positive electrode lead paste, thereby lowering the internal resistance of the lead-acid battery and improving its charge-discharge efficiency and cycle life. Mixing magnesium fluorosilicate with lead powder in solution helps achieve better compatibility and uniformity.

[0011] Furthermore, the preparation method of the magnesium fluorosilicate solution includes: dissolving magnesium fluorosilicate crystals in pure water at a temperature of 25-30°C and a conductivity of 100-200 S / m at a mass ratio of 1:1, and filtering to obtain a magnesium fluorosilicate solution with an iron content ≤0.004% and a chloride content ≤0.004% by mass. Controlling the content of iron and chloride ions can effectively avoid the problem of excessive hydrogen gas during the battery chemical reaction.

[0012] Furthermore, the preparation method of the positive electrode lead paste includes:

[0013] (1) Lead powder, short fiber, colloidal graphite, antimony trioxide and stannous sulfate are dry mixed to obtain a mixed dry powder;

[0014] (2) Add pure water and prepared magnesium fluorosilicate solution to the mixed dry powder for wet mixing, and then add sulfuric acid solution to obtain the positive electrode lead paste.

[0015] Furthermore, in step (2), pure water and magnesium fluorosilicate solution are added simultaneously, within 1-2 minutes, followed by wet stirring for 5-8 minutes. Adding within a short time avoids water evaporation affecting the accuracy of the added amount.

[0016] Furthermore, in step (2), the addition time of the 1.40 g / mL sulfuric acid solution is controlled within 12–15 minutes. Adding the sulfuric acid solution within the specified time helps maintain a constant temperature during the stirring of the paste.

[0017] Furthermore, the apparent specific gravity of the lead paste for the positive electrode of the lead-acid battery is 4.42–4.52 g / cm³. 3 The moisture content and porosity of lead paste should be controlled to ensure its electrochemical performance.

[0018] Furthermore, before the positive electrode grid is coated with lead paste, it is pretreated by soaking it in a carbonate solution, wherein the carbonate solution is prepared by dissolving sodium bicarbonate or sodium carbonate and pure water in a mass ratio of 1:10.

[0019] This invention involves immersing the cast lead-tin-calcium alloy grid in a carbonate solution and then drying it to form an alkaline protective layer on the surface of each grid rib. This reduces the corrosion rate of the battery grid by the sulfuric acid electrolyte, thereby improving the grid's corrosion resistance.

[0020] Furthermore, the pretreatment involves immersing the cast lead-tin-calcium alloy grid in a carbonate solution for 5–10 minutes, followed by drying. Immersion in the carbonate solution forms a protective layer on the surface of the grid ribs, which neutralizes and resists the corrosive sulfuric acid.

[0021] Furthermore, the method for preparing the carbonate solution includes: mixing sodium bicarbonate or sodium carbonate with pure water at a temperature of 18-25°C and a conductivity of 100-200 S / m at a mass ratio of 1:10, dissolving and allowing it to stand, and then filtering to obtain a carbonate solution with an iron mass percentage content ≤0.004% and a chlorine mass percentage content ≤0.004%.

[0022] The present invention also provides a lead-acid battery, including the lead-acid battery positive plate.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] This invention relates to a lead-acid battery positive electrode paste preparation process. In this process, pure water and a prepared magnesium fluorosilicate solution are added to the mixed dry powder for wet mixing, followed by the addition of sulfuric acid solution. Magnesium fluorosilicate is readily soluble in water and dilute acid, facilitating solution preparation. In solution form, it is easier to mix evenly with lead powder. Furthermore, magnesium fluorosilicate is not easily deliquescent and exhibits solidification and shrinkage properties. As a lead-acid paste additive, it can improve the stability of the positive electrode active material, resulting in a more uniform PbO2 molecular structure. This creates a more balanced reaction with the electrolyte within a tightly packed pore framework, reducing the rapid decrease in active material density and the rapid separation and shedding of active material, effectively suppressing the rapid decay of battery discharge capacity. This formulation is suitable for use in lead-acid-starved valve-regulated electric vehicle power batteries.

[0025] Compared to finished batteries made with equivalent positive electrode grids and positive electrode paste, the positive electrode plate provided by this invention has the characteristics of strong binding force of active materials, high temperature resistance, and crack resistance. It can improve battery conductivity, long-life cycle charge and discharge characteristics, etc. It has a certain inhibitory effect on preventing premature mud decomposition of active materials and active material shedding in the later stage of battery life. The battery charge and discharge efficiency is increased by more than 2.2%, and the battery cycle life is increased by more than 8%. Attached Figure Description

[0026] Figure 1 The graph shows the cycle life test results of the battery pack in Example 2.

[0027] Figure 2 The graph shows the cycle life test results of the battery pack in Example 3.

[0028] Figure 3 The graph shows the cycle life test results of the battery pack in Comparative Example 1.

[0029] Figure 4 The graph shows the cycle life test results for Comparative Example 4 battery pack. Detailed Implementation

[0030] The present invention will be further described below with reference to specific embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Any modifications or substitutions made to the methods, steps, or conditions of the present invention without departing from the spirit and essence of the invention are within the scope of the invention.

[0031] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; the materials and reagents used are commercially available unless otherwise specified.

[0032] The technical requirements for sodium bicarbonate powder (NaHCO3) used in the following examples are as follows: Appearance: white powder or monoclinic crystalline powder; Density: 2.159 g / cm³ 3 Melting point: 270℃; Molecular weight: 84.01.

[0033] Magnesium fluorosilicate crystals (MgSiF6·6H2O) technical requirements: Appearance: colorless or white rhombic or needle-like crystals; Density: 1.788 g / cm³ 3 Melting point: 120℃; Molecular weight: 274.47.

[0034] Example 1

[0035] I. Preparation of sodium bicarbonate solution

[0036] Sodium bicarbonate powder is dissolved in pure water (conductivity 100-200 S / m) at a ratio of 1:10. Specifically, the sodium bicarbonate powder is dissolved in pure water by stirring, ultrasonication, and maintaining the water temperature at 18-25℃. After stirring for 10 minutes and letting it stand for 5 minutes to allow precipitation, impurities are filtered out to obtain the finished sodium bicarbonate solution. This solution is then kept at 25℃, containing impurities of iron (Fe content ≤ 0.004%) and chlorine (Cl content ≤ 0.004%).

[0037] II. Preparation of Magnesium Fluorosilicate Solution

[0038] Magnesium fluorosilicate crystals are dissolved in pure water (conductivity 100-200 S / m) at a 1:1 ratio. Specifically, the magnesium fluorosilicate is dissolved in pure water by stirring and ultrasonication, with the water temperature controlled at 25-30℃. After stirring for 10 minutes and letting it stand for 10 minutes to allow precipitation, impurities are filtered out, resulting in the finished magnesium fluorosilicate solution. This solution is then kept at 25℃, containing impurities such as iron (Fe content ≤ 0.004%) and chlorine (Cl content ≤ 0.004%).

[0039] III. Preparation of Positive Electrode Plates

[0040] 1. Pretreatment of grating

[0041] Take the lead-tin-calcium alloy grid of the finished cast lead-acid battery model 6-DZF-22 and immerse it in the sodium bicarbonate solution prepared in step 1 for 5 minutes.

[0042] 2. Preparation of lead paste

[0043] To every 1000 kg of lead powder, add 0.8 kg of short fibers, 3.0 kg of colloidal graphite, 1.0 kg of antimony trioxide, and 2.5 kg of stannous sulfate. Dry mix for 7 minutes. Within 1 minute, add 110 kg of pure water and 2.0 kg of the magnesium fluorosilicate solution prepared in step 2, and then wet stir for 5 minutes. Finally, within 14 minutes, add 82 kg of sulfuric acid with a specific gravity of 1.40 g / mL and mix. Prepare a separate amount of pure water to adjust the specific gravity of the resulting lead paste to be controlled between 4.42 and 4.46 g / mL.

[0044] 3. Apply lead paste to the pretreated grid according to conventional process, and then dry, cure, dry, and brush the edges to obtain the positive electrode plate.

[0045] Example 2

[0046] 1. Pretreatment of grating

[0047] Take the lead-tin-calcium alloy grid of the finished cast lead-acid battery model 6-DZF-22 and immerse it in the sodium bicarbonate solution prepared in step 1 for 5 minutes.

[0048] 2. Preparation of lead paste

[0049] To every 1000 kg of lead powder, add 1.0 kg of short fibers, 4.0 kg of colloidal graphite, 2.0 kg of antimony trioxide, and 3.0 kg of stannous sulfate. Dry mix for 8 minutes. Within 1 minute, add 100 kg of pure water and 3.0 kg of magnesium fluorosilicate solution prepared in step 2 of Example 1, and then wet stir for 6 minutes. Finally, within 14 minutes, add 86 kg of sulfuric acid with a specific gravity of 1.40 g / mL and mix. Prepare a separate amount of pure water to adjust the specific gravity of the resulting lead paste to be controlled between 4.44 and 4.48 g / mL.

[0050] 3. Apply lead paste to the pretreated grid according to conventional process, and then dry, cure, dry, and brush the edges to obtain the positive electrode plate.

[0051] Example 3

[0052] 1. Pretreatment of grating

[0053] Take the lead-tin-calcium alloy grid of the finished cast lead-acid battery model 6-DZF-22 and immerse it in the sodium bicarbonate solution prepared in step 1 for 5 minutes.

[0054] 2. Preparation of lead paste

[0055] To every 1000 kg of lead powder, add 1.0 kg of short fibers, 3.0 kg of colloidal graphite, 0.1 kg of antimony trioxide, and 3.0 kg of stannous sulfate. Dry mix for 9 minutes. Within 1 minute, add 100 kg of pure water and 4.0 kg of the magnesium fluorosilicate solution prepared in step 2 of Example 1, and then wet stir for 7 minutes. Finally, within 14 minutes, add 88 kg of sulfuric acid with a specific gravity of 1.40 g / mL and mix. Prepare a separate amount of pure water to adjust the specific gravity of the resulting lead paste to be controlled between 4.48 and 4.52 g / mL.

[0056] 3. Apply lead paste to the pretreated grid according to conventional process, and then dry, cure, dry, and brush the edges to obtain the positive electrode plate.

[0057] Comparative Example 1

[0058] 1. Preparation of lead paste

[0059] To every 1000 kg of lead powder, add 0.8 kg of short fiber, 3.0 kg of colloidal graphite, 1.0 kg of antimony trioxide, and 2.5 kg of stannous sulfate. Dry mix for 6 minutes, then add 110 kg of pure water within 1 minute and stir for another 6 minutes. Finally, add 82 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 4.46 and 4.47 g / mL.

[0060] 2. Lead paste is applied to the battery grid without pretreatment by soaking in sodium bicarbonate solution according to conventional process. After drying, curing, drying and brushing of the edges, the positive electrode green plate is obtained.

[0061] Comparative Example 2

[0062] 1. Preparation of lead paste

[0063] To every 1000 kg of lead powder, add 0.9 kg of short fiber, 3.5 kg of colloidal graphite, 0.15 kg of antimony trioxide, and 2.5 kg of stannous sulfate. Dry mix for 7 minutes, then add 112 kg of pure water within 1 minute and stir for another 7 minutes. Finally, add 84 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 between 4.47 and 4.48 g / mL.

[0064] 2. Lead paste is applied to the battery grid without pretreatment by soaking in sodium bicarbonate solution according to conventional process. After drying, curing, drying and brushing of the edges, the positive electrode green plate is obtained.

[0065] Comparative Example 3

[0066] 1. Preparation of lead paste

[0067] To every 1000 kg of lead powder, add 1.0 kg of short fiber, 4.0 kg of colloidal graphite, 0.2 kg of antimony trioxide, and 3.0 kg of stannous sulfate. Dry mix for 8 minutes, then add 115 kg of pure water within 1 minute and stir for 8 minutes. Finally, add 88 kg of sulfuric acid with a specific gravity of 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 controlled between 4.49 and 4.52 g / mL.

[0068] 2. Lead paste is applied to the battery grid without pretreatment by soaking in sodium bicarbonate solution according to conventional process. After drying, curing, drying and brushing of the edges, the positive electrode green plate is obtained.

[0069] Comparative Example 4

[0070] 1. Pretreatment of grating

[0071] Take the lead-tin-calcium alloy grid of the finished cast lead-acid battery model 6-DZF-22 and immerse it in the sodium bicarbonate solution prepared in step 1 for 5 minutes.

[0072] 2. Preparation of lead paste

[0073] To every 1000 kg of lead powder, add 1.0 kg of short fiber, 3.5 kg of colloidal graphite, 1.0 kg of antimony trioxide, and 2.5 kg of stannous sulfate. Dry mix for 8 minutes, then add 112 kg of pure water within 1 minute and stir for 7 minutes. Finally, add 86 kg of sulfuric acid with a specific gravity of 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 controlled between 4.47 and 4.49 g / mL.

[0074] 3. Apply lead paste to the pretreated grid according to conventional process, and then dry, cure, dry, and brush the edges to obtain the positive electrode plate.

[0075] Test Example 1

[0076] The positive electrode plates prepared in Examples 1-3 and Comparative Examples 1-4 were used to make lead-acid battery model 6-DZF-22 by combining them with negative electrode plates.

[0077] Battery performance test: In a laboratory environment of 25±2℃, four assembled battery packs were sampled. The battery packs were discharged at IC211.0A to the termination voltage of 1.75V / cell. The discharge time was recorded and the actual discharge capacity of the battery was calculated. The results are shown in Table 1 and Table 2.

[0078] Table 1. Battery Pack Performance Tests (Example)

[0079]

[0080] Table 2. Performance Tests of Comparative Battery Packs

[0081]

[0082] Based on the results in Tables 1 and 2, the average maximum capacity of the batteries prepared in Examples 1-3 during the third discharge was 22.47 Ah, while the average maximum capacity of the batteries prepared in Comparative Examples 1-3 was 21.43 Ah. The average high-current discharge time of the batteries in the Examples was 26.43 min, while that of the batteries in the Comparative Examples was 24.43 min. The batteries prepared using the method of this invention have a higher specific capacity (by approximately 4.85%) and a longer high-current discharge time (by 2 min).

[0083] Test Example 2

[0084] The positive electrode plates from Examples 2, 3, Comparative Example 1, and Comparative Example 4 were used to fabricate lead-acid batteries (model 6-DZF-22) by combining them with negative electrode plates. Four batteries from each group were sampled and assembled into 48V / 22Ah battery packs for cycle life testing. The test conditions were rapid cycle testing: charging at 10A with a charging voltage limit of 59.6V / pack for 6 hours; discharging at 11.0A with a discharging voltage limit of 42V / pack. The results are as follows. Figure 1-4 As shown.

[0085] like Figure 1 and Figure 3 As shown, the battery pack of Example 2 has a cycle life of 384 cycles, while the battery pack of Comparative Example 1 has a cycle life of 301 cycles. The battery pack prepared using the method of the present invention has a cycle life extended by approximately 83 cycles, which is an improvement of 27.5%.

[0086] like Figure 2 and Figure 4 As shown, the battery pack in Example 3 has a cycle life of 373 cycles, while the battery pack in Comparative Example 4 has a cycle life of 335 cycles. The battery pack prepared using the method of the present invention has a cycle life extended by approximately 38 cycles, representing an improvement of 11%.

[0087] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A positive electrode plate for a lead-acid battery, comprising a positive electrode grid and positive electrode lead paste coated on the positive electrode grid, characterized in that, The positive electrode lead paste comprises lead powder, sulfuric acid solution, pure water, and additives. Based on 100 parts by weight of lead powder, the sulfuric acid solution comprises 8.2–8.8 parts; the pure water comprises 10.0–11.0 parts; the additives include 0.2–0.4 parts magnesium fluorosilicate solution, 0.08–0.10 parts short fibers, 0.3–0.4 parts colloidal graphite, 0.01–0.2 parts antimony trioxide, and 0.25–0.3 parts stannous sulfate; wherein the magnesium fluorosilicate solution is prepared by dissolving magnesium fluorosilicate crystals in pure water at a mass ratio of 1:

1.

2. The positive electrode plate of a lead-acid battery as described in claim 1, characterized in that, The preparation method of the magnesium fluorosilicate solution includes: dissolving magnesium fluorosilicate crystals in pure water at a temperature of 25-30°C and a conductivity of 100-200 S / m at a mass ratio of 1:1, and then filtering to obtain a magnesium fluorosilicate solution with an iron mass percentage content ≤0.004% and a chlorine mass percentage content ≤0.004%.

3. The positive electrode plate of a lead-acid battery as described in claim 1, characterized in that, The preparation method of the positive electrode lead paste includes: (1) Lead powder, short fiber, colloidal graphite, antimony trioxide and stannous sulfate are dry mixed to obtain a mixed dry powder; (2) Add pure water and prepared magnesium fluorosilicate solution to the mixed dry powder for wet mixing, and then add sulfuric acid solution to obtain the positive electrode lead paste.

4. The positive electrode plate of a lead-acid battery as described in claim 3, characterized in that, In step (2), pure water and magnesium fluorosilicate solution are added simultaneously and completed within 1 to 2 minutes, followed by wet stirring for 5 to 8 minutes.

5. The positive electrode plate of a lead-acid battery as described in claim 3, characterized in that, In step (2), the addition time of the 1.40 g / mL sulfuric acid solution is controlled at 12 to 15 min.

6. The positive electrode plate of a lead-acid battery as described in claim 1, characterized in that, The apparent specific gravity of the lead paste for the positive electrode of the lead-acid battery is 4.42–4.52 g / cm³. 3 .

7. The positive electrode plate of a lead-acid battery as described in claim 1, characterized in that, Before being coated with lead paste, the positive electrode grid is pretreated by soaking it in a carbonate solution. The carbonate solution is prepared by dissolving sodium bicarbonate or sodium carbonate in pure water at a mass ratio of 1:

10.

8. The positive electrode plate of a lead-acid battery as described in claim 7, characterized in that, The pretreatment involves immersing the cast lead-tin-calcium alloy grid plate in a carbonate solution for 5–10 minutes, then removing and drying it.

9. The positive electrode plate of a lead-acid battery as described in claim 7, characterized in that, The method for preparing the carbonate solution includes: mixing sodium bicarbonate or sodium carbonate with pure water at a temperature of 18-25°C and a conductivity of 100-200 S / m at a mass ratio of 1:10, dissolving and allowing it to stand, and then filtering to obtain a carbonate solution with an iron mass percentage content ≤0.004% and a chlorine mass percentage content ≤0.004%.

10. A lead-acid battery, characterized in that, Includes the lead-acid battery positive plate as described in any one of claims 1-9.

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