High-capacity lead paste as well as preparation method and application thereof

Abstract

The invention discloses a high-capacity lead paste and a preparation method and application thereof, and belongs to the technical field of lead-acid storage battery manufacturing, the preparation method of the high-capacity lead paste comprises the following steps: S1, adding lead powder, sulfuric acid, short fibers, graphite, xanthan gum and modified sodium lignin sulfonate into a paste mixer, and carrying out dry stirring and mixing for 5-10 min; then adding water into the paste mixer, and stirring for 5-9 minutes; and S2, sulfuric acid is added into the paste mixing machine while stirring is conducted, the time of the sulfuric acid adding process is 16-20 min, the temperature of the sulfuric acid adding process is 57-60 DEG C, stirring continues to be conducted for 10-15 min after the sulfuric acid is added, the high-capacity lead paste is obtained, and when the temperature of the high-capacity lead paste is lower than 45 DEG C, the high-capacity lead paste can be discharged for plate coating. When the prepared lead paste is applied to a lead-acid storage battery, the cycle performance and the capacity of the battery can be improved.

Description

Technical Field

[0001] The invention belongs to the technical field of lead-acid battery manufacturing, and in particular relates to a high-capacity lead paste and a preparation method and application thereof. Background Art

[0002] Lead-acid batteries are popular in the market due to their low cost, safety, reliability, mature production technology, long service life, easy recycling and stable electrical performance. However, their application is limited by their weaknesses in terms of weight-to-energy ratio and recycling. The core component of the battery is the plate, and the performance of the plate depends on the grid and lead paste.

[0003] The patent with the patent announcement number CN108400304B discloses a positive lead paste for lead-acid batteries. The patent uses lead powder, sulfuric acid, water, short fibers, xanthan gum and graphite as raw materials. By studying the dosage ratio of each raw material, a positive lead paste for lead-acid batteries is prepared. The lead-acid battery prepared by using the positive lead paste has high initial capacity, slow decay, long cycle life, and large large current discharge and low temperature charge and discharge performance. However, materials such as graphite are easy to agglomerate and have poor dispersibility. After agglomeration, the capacity and cycle performance of the lead-acid battery prepared by the positive lead paste will be affected. Summary of the invention

[0004] In order to solve the problem that materials such as graphite in the prior art are easy to agglomerate and have poor dispersibility, and the agglomeration will affect the capacity and cycle performance of lead-acid batteries prepared with positive electrode lead paste, the purpose of the present invention is to provide a high-capacity lead paste and a preparation method and application thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] In a first aspect, the present invention provides a high-capacity lead paste, comprising the following raw materials, by weight: 70-80 parts of lead powder, 3-7 parts of sulfuric acid, 6-18 parts of water, 0.5-1 parts of short fibers, 0.1-0.3 parts of graphite, 0.1-0.3 parts of xanthan gum, and 0.4-0.8 parts of modified sodium lignin sulfonate.

[0007] Graphite can improve the electronic conductivity between lead dioxide particles, while increasing the porosity of the positive plate, effectively improving the utilization rate of the positive active material; in addition, graphite can make full use of the active materials in the middle and lower parts of the plate, disperse the current density of the entire plate, and effectively inhibit the attenuation of the utilization rate of the positive active material, thereby increasing the capacity of the battery and improving the service life of the battery.

[0008] Furthermore, the density of sulfuric acid is 1.4 g / cm 3 .

[0009] Furthermore, the short fibers are polyester fibers with a length of 2-6 mm.

[0010] Furthermore, the particle size of the xanthan gum is 20-200 mesh.

[0011] Furthermore, the preparation method of modified sodium lignin sulfonate is:

[0012] Step A1: dissolving acrylic acid and mercaptoethylamine in deionized water, stirring evenly, adding 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS), reacting at 20-30° C. for 20-30 min, washing, and freeze-drying to obtain an intermediate;

[0013] Among them, the usage ratio of acrylic acid, mercaptoethylamine, deionized water, EDC and NHS is 0.72g:0.77g:50mL:3.83g:2.31g.

[0014] In the above reaction steps, under the catalytic action of EDC and NHS, the carboxyl group of acrylic acid and the amino group of mercaptoethylamine undergo amide reaction to obtain an intermediate.

[0015] Step A2: the intermediate is mixed with deionized water, sodium lignin sulfonate is added, the temperature is raised to 60° C., and then hydrogen peroxide and ascorbic acid with a mass concentration of 30% are added, the mixture is reacted for 4-5 hours, and then freeze-dried to obtain thiolated sodium lignin sulfonate;

[0016] The usage ratio of the intermediate, deionized water, sodium lignin sulfonate, hydrogen peroxide and ascorbic acid is 8.1 g: 100 mL: 32.7 g: 2.18 g: 0.654 g.

[0017] In the above reaction steps, under the action of initiators hydrogen peroxide and ascorbic acid, sodium lignin sulfonate undergoes graft copolymerization reaction with the intermediate to obtain thiolated sodium lignin sulfonate. Sodium lignin sulfonate itself has a relatively complex composition, low surface activity, and poor dispersion effect. By graft copolymerizing sodium lignin sulfonate with the intermediate, the intermediate contains hydrophilic groups such as thiol and amide groups, which can improve the dispersibility of sodium lignin sulfonate and can be better adsorbed on the surface of the particles. In the subsequent preparation of lead paste, it is beneficial to further improve the dispersibility of the raw materials.

[0018] Step A3: Add thiolated sodium lignin sulfonate into water, then add silver nitrate aqueous solution, mix well, then add sodium borohydride aqueous solution, stir and react at room temperature for 8-9 hours to obtain modified sodium lignin sulfonate.

[0019] The usage ratio of thiolated sodium lignin sulfonate, water, silver nitrate aqueous solution and sodium borohydride aqueous solution is 9g:100mL:100mL:20-25mL.

[0020] In the above reaction steps, silver nitrate is ionized into silver ions in water, and sodium borohydride, as a strong reducing agent, can reduce silver ions to silver atoms, thereby forming nano silver particles. The thiolated sodium lignin sulfonate contains thiol groups, which have a strong coordination effect with silver. The sulfonic acid groups contained can give the prepared silver nanoclusters good water solubility, thereby stabilizing the nano silver particles and preventing them from agglomerating, so that the nano silver is evenly dispersed in the thiolated sodium lignin sulfonate.

[0021] Furthermore, the concentration of the silver nitrate aqueous solution is 0.01 mol / L, and the concentration of the sodium borohydride aqueous solution is 0.5 mol / L.

[0022] In a second aspect, the present invention provides a method for preparing a high-capacity lead paste, comprising the following steps:

[0023] Step S1: Add lead powder, sulfuric acid, short fibers, graphite, xanthan gum, and modified sodium lignin sulfonate into a paste mixer and stir for 5-10 minutes; then add water into the paste mixer and stir for 5-9 minutes;

[0024] Step S2: Add sulfuric acid to the paste mixer while stirring. Continue stirring for 10-15 minutes after the sulfuric acid is added to obtain a high-capacity lead paste. When the temperature of the high-capacity lead paste is lower than 45°C, the paste can be taken out for coating the board.

[0025] Furthermore, in step S2, the time of adding sulfuric acid is 16-20 minutes, and the temperature of adding sulfuric acid is 57°C-60°C.

[0026] In a third aspect, the present invention provides an application of a high-capacity lead paste in a lead-acid battery.

[0027] Beneficial effects of the present invention:

[0028] 1. The present invention adds modified sodium lignin sulfonate in the process of preparing lead paste, and the modified sodium lignin sulfonate is prepared by thiolated sodium lignin sulfonate composite nanosilver. The long-chain molecular structure of the modified sodium lignin sulfonate can form a steric hindrance layer around the solid particles. This steric hindrance layer can prevent direct contact and agglomeration between particles, thereby improving the dispersion stability of graphite. At the same time, the molecular chain of the modified sodium lignin sulfonate can form a network structure in water, increase the viscosity of the system, make the particles better suspended in the system, prevent the particles from sinking and stratification, thereby increasing the capacity of the battery and the service life of the battery. Nanosilver has a nanoscale effect and excellent electrical conductivity. The uniformly dispersed nanosilver forms a conductive network in the lead paste matrix, significantly improving the electrical conductivity of the lead paste. This improvement in electrical conductivity accelerates the transmission speed of charge in the lead paste, reduces the internal resistance of the battery, thereby improving the charge and discharge rate, energy density and cycle stability of the lead-acid battery, and ultimately prolongs the service life of the battery.

[0029] 2. Modified sodium lignin sulfonate is a colloid, and the sulfonic acid group and amide group in the modified sodium lignin sulfonate are hydrophilic, which can form more lead dioxide hydration areas when combined with lead dioxide, which is beneficial to improve the utilization rate of lead dioxide; and the colloidal modified sodium lignin sulfonate can be more effectively dispersed in the lead paste, preventing the agglomeration of lead powder and graphite particles, thereby improving the uniformity and stability of the lead paste, which is beneficial to form a uniform conductive network, thereby improving the overall performance of the battery. DETAILED DESCRIPTION

[0030] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Example 1

[0032] This embodiment provides a high-capacity lead paste, which includes the following raw materials by weight: 70 parts of lead powder, 3 parts of sulfuric acid, 6 parts of water, 0.5 parts of short fibers, 0.1 parts of graphite, 0.1 parts of xanthan gum, and 0.4 parts of modified sodium lignin sulfonate. The density of sulfuric acid is 1.4 g / cm 3 , the short fiber is polyester fiber with a length of 4 mm, and the particle size of xanthan gum is 100.

[0033] The preparation method of modified sodium lignin sulfonate is:

[0034] Step A1: 0.72 g of acrylic acid and 0.77 g of mercaptoethylamine were dissolved in 50 mL of deionized water, stirred evenly, and then 3.83 g of EDC and 2.31 g of NHS were added, reacted at 20° C. for 20 min, washed, and freeze-dried to obtain an intermediate;

[0035] Step A2: 8.1 g of the intermediate was mixed with 100 mL of deionized water, and 32.7 g of sodium lignin sulfonate was added at the same time, and the temperature was raised to 60° C., and then 2.18 g of hydrogen peroxide with a mass concentration of 30% and 0.654 g of ascorbic acid were added. After reacting for 4 hours, the mixture was freeze-dried to obtain thiolated sodium lignin sulfonate;

[0036] Step A3: Add 9 g of thiolated sodium lignin sulfonate to 100 mL of water, then add 100 mL of 0.01 mol / L silver nitrate aqueous solution, mix well, add 20 mL of 0.5 mol / L sodium borohydride aqueous solution, stir and react at room temperature for 8 h to obtain modified sodium lignin sulfonate.

[0037] The preparation method of high-capacity lead paste comprises the following steps:

[0038] Step S1: Add lead powder, sulfuric acid, short fibers, graphite, xanthan gum, and modified sodium lignin sulfonate into a paste mixer and stir for 5 minutes; then add water into the paste mixer and stir for 5 minutes;

[0039] Step S2: Add sulfuric acid to the paste mixer while stirring. The time for adding sulfuric acid is 16 minutes and the temperature for adding sulfuric acid is 57°C. After the addition of sulfuric acid is completed, continue stirring for 10 minutes to obtain high-capacity lead paste. When the temperature of the high-capacity lead paste is lower than 45°C, the paste can be taken out for coating the board.

[0040] Example 2

[0041] This embodiment provides a high-capacity lead paste, which includes the following raw materials by weight: 72 parts of lead powder, 4 parts of sulfuric acid, 9 parts of water, 0.75 parts of short fibers, 0.2 parts of graphite, 0.2 parts of xanthan gum, and 0.5 parts of modified sodium lignin sulfonate. The density of sulfuric acid is 1.4 g / cm 3 , the short fiber is polyester fiber with a length of 4 mm, and the particle size of xanthan gum is 100 mesh.

[0042] The preparation method of modified sodium lignin sulfonate is:

[0043] Step A1: 0.72 g of acrylic acid and 0.77 g of mercaptoethylamine were dissolved in 50 mL of deionized water, stirred evenly, and then 3.83 g of EDC and 2.31 g of NHS were added, reacted at 25° C. for 25 min, washed, and freeze-dried to obtain an intermediate;

[0044] Step A2: 8.1 g of the intermediate was mixed with 100 mL of deionized water, and 32.7 g of sodium lignin sulfonate was added at the same time, and the temperature was raised to 60° C., and then 2.18 g of 30% hydrogen peroxide and 0.654 g of ascorbic acid were added. After reacting for 4.5 hours, the mixture was freeze-dried to obtain thiolated sodium lignin sulfonate;

[0045] Step A3: Add 9 g of thiolated sodium lignin sulfonate to 100 mL of water, then add 100 mL of 0.01 mol / L silver nitrate aqueous solution, mix well, add 23 mL of 0.5 mol / L sodium borohydride aqueous solution, stir and react at room temperature for 8.5 h to obtain modified sodium lignin sulfonate.

[0046] The preparation method of high-capacity lead paste comprises the following steps:

[0047] Step S1: Add lead powder, sulfuric acid, short fibers, graphite, xanthan gum, and modified sodium lignin sulfonate into a paste mixer and stir and mix for 8 minutes; then add water into the paste mixer and stir for 5-9 minutes;

[0048] Step S2: Add sulfuric acid to the paste mixer while stirring. The time for adding sulfuric acid is 18 minutes and the temperature for adding sulfuric acid is 59°C. After the addition of sulfuric acid is completed, continue stirring for 12 minutes to obtain high-capacity lead paste. When the temperature of the high-capacity lead paste is lower than 45°C, the paste can be taken out for coating the board.

[0049] Example 3

[0050] This embodiment provides a high-capacity lead paste, which includes the following raw materials by weight: 75 parts of lead powder, 5 parts of sulfuric acid, 12 parts of water, 0.75 parts of short fibers, 0.2 parts of graphite, 0.2 parts of xanthan gum, and 0.6 parts of modified sodium lignin sulfonate. The density of sulfuric acid is 1.4 g / cm 3 , the short fiber is polyester fiber with a length of 4 mm, and the particle size of xanthan gum is 100 mesh.

[0051] The preparation method of modified sodium lignin sulfonate is:

[0052] Step A1: 0.72 g of acrylic acid and 0.77 g of mercaptoethylamine were dissolved in 50 mL of deionized water, stirred evenly, and then 3.83 g of EDC and 2.31 g of NHS were added, reacted at 30° C. for 30 min, washed, and freeze-dried to obtain an intermediate;

[0053] Step A2: 8.1 g of the intermediate was mixed with 100 mL of deionized water, and 32.7 g of sodium lignin sulfonate was added at the same time, and the temperature was raised to 60° C., and then 2.18 g of hydrogen peroxide with a mass concentration of 30% and 0.654 g of ascorbic acid were added. After reacting for 5 hours, the mixture was freeze-dried to obtain thiolated sodium lignin sulfonate;

[0054] Step A3: Add 9 g of thiolated sodium lignin sulfonate to 100 mL of water, then add 100 mL of 0.01 mol / L silver nitrate aqueous solution, mix well, add 25 mL of 0.5 mol / L sodium borohydride aqueous solution, stir and react at room temperature for 9 hours to obtain modified sodium lignin sulfonate.

[0055] The preparation method of high-capacity lead paste comprises the following steps:

[0056] Step S1: Add lead powder, sulfuric acid, short fibers, graphite, xanthan gum, and modified sodium lignin sulfonate into a paste mixer and stir for 10 minutes; then add water into the paste mixer and stir for 5-9 minutes;

[0057] Step S2: Add sulfuric acid to the paste mixer while stirring. The time for adding sulfuric acid is 20 minutes and the temperature for adding sulfuric acid is 60°C. After the addition of sulfuric acid is completed, continue stirring for 15 minutes to obtain high-capacity lead paste. When the temperature of the high-capacity lead paste is lower than 45°C, the paste can be taken out for coating the board.

[0058] Example 4

[0059] Compared with Example 3, this embodiment is different in that:

[0060] A high-capacity lead paste comprises the following raw materials, by weight: 78 parts of lead powder, 6 parts of sulfuric acid, 15 parts of water, 0.75 parts of short fibers, 0.2 parts of graphite, 0.2 parts of xanthan gum, and 0.7 parts of modified sodium lignin sulfonate. The remaining raw materials and steps are the same as those in Example 3.

[0061] Example 5

[0062] Compared with Example 3, this embodiment is different in that:

[0063] A high-capacity lead paste comprises the following raw materials, by weight: 80 parts of lead powder, 7 parts of sulfuric acid, 18 parts of water, 1 part of short fiber, 0.3 parts of graphite, 0.3 parts of xanthan gum, and 0.8 parts of modified sodium lignin sulfonate. The remaining raw materials and steps are the same as those in Example 3.

[0064] Comparative Example 1

[0065] Compared with Example 1, this comparative example is different in that:

[0066] The preparation method of modified sodium lignin sulfonate is:

[0067] Step A1: 0.72 g of acrylic acid and 0.77 g of mercaptoethylamine were dissolved in 50 mL of deionized water, stirred evenly, and then 3.83 g of EDC and 2.31 g of NHS were added, reacted at 20° C. for 20 min, washed, and freeze-dried to obtain an intermediate;

[0068] Step A2: 8.1 g of the intermediate was mixed with 100 mL of deionized water, and 32.7 g of sodium lignin sulfonate was added at the same time. The temperature was raised to 60° C., and then 2.18 g of 30% hydrogen peroxide and 0.654 g of ascorbic acid were added. After reacting for 4 hours, the mixture was freeze-dried to obtain thiolated sodium lignin sulfonate.

[0069] The remaining materials and steps are the same as in Example 1.

[0070] Comparative Example 2

[0071] Compared with Example 1, this comparative example is different in that the modified sodium lignin sulfonate is replaced by sodium lignin sulfonate, and the remaining raw materials and steps are the same as Example 1.

[0072] Comparative Example 3

[0073] The difference between this comparative example and Example 1 is that modified sodium lignin sulfonate is not added, and the other raw materials and steps are the same as Example 1.

[0074] The lead pastes prepared in Examples 1 to 5 and Comparative Examples 1 to 3 were used to produce polar plates, which were then assembled into 6-DZF-20 batteries. The test items were as follows, and the test results are shown in Table 1:

[0075] (1) 2h rate discharge: According to Article 5.5 of the national battery standard GB / T22199-2017, after the battery is fully charged, it should be kept at rest for 1-24h in an environment with a temperature of 25±2℃, and discharged at a constant current of 10A until the battery voltage reaches 10.5V. The 2h rate capacity Ca should reach the C2 standard within three cycles.

[0076] (2) High current discharge: According to Article 5.5 of the national battery standard GB / T22199-2017, after the battery is fully charged, it should be placed in an environment with a temperature of 25±5℃ for 1-4 hours, and then discharged at a current of 3.6A until the battery voltage reaches 10.5V. The discharge duration should be no less than 25min.

[0077] (3) Cycle life: In accordance with Article 5.12 of the national battery standard GB / T22199-2017, in an environment with a temperature of 25±5°C, discharge at a current of 10A for 1.6h, and then charge at a constant voltage of 16V (current limit 4A) for 6.4h as one cycle. When the terminal voltage of the battery is lower than 10.5V for three consecutive times after discharging for 1.6h, the battery cycle life is terminated. The total cycle life is not less than 350 times.

[0078] Table 1

[0079]

[0080]

[0081] It can be seen from Table 1 that the comprehensive performance of Examples 1 to 5 is better than that of Comparative Examples 1 to 3.

[0082] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0083] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-capacity lead paste, characterized in that: The raw materials are as follows, measured by weight: 70-80 parts of lead powder, 3-7 parts of sulfuric acid, 6-18 parts of water, 0.5-1 parts of short fibers, 0.1-0.3 parts of graphite, 0.1-0.3 parts of xanthan gum, and 0.4-0.8 parts of modified sodium lignin sulfonate.

2. The high-capacity lead paste according to claim 1, characterized in that: The density of sulfuric acid is 1.4 g / cm 3 .

3. The high-capacity lead paste according to claim 1, characterized in that: The staple fibers are polyester fibers with a length of 2-6 mm.

4. The high-capacity lead paste according to claim 1, characterized in that: The particle size of xanthan gum is 20-200 mesh.

5. The high-capacity lead paste according to claim 1, characterized in that: The preparation method of modified sodium lignin sulfonate is: Step A1: dissolve acrylic acid and mercaptoethylamine in deionized water, stir well, add EDC and NHS, react at 20-30° C. for 20-30 min, wash, and freeze-dry to obtain an intermediate; Step A2: the intermediate is mixed with deionized water, sodium lignin sulfonate is added, the temperature is raised to 60° C., and then hydrogen peroxide and ascorbic acid with a mass concentration of 30% are added, the mixture is reacted for 4-5 hours, and then freeze-dried to obtain thiolated sodium lignin sulfonate; Step A3: Add thiolated sodium lignin sulfonate into water, then add silver nitrate aqueous solution, mix well, then add sodium borohydride aqueous solution, stir and react at room temperature for 8-9 hours to obtain modified sodium lignin sulfonate.

6. The high-capacity lead paste according to claim 5, characterized in that: In step A1, the usage ratio of acrylic acid, mercaptoethylamine, deionized water, EDC, and NHS is 0.72 g: 0.77 g: 50 mL: 3.83 g: 2.31 g.

7. The high-capacity lead paste according to claim 5, characterized in that: In step A2, the usage ratio of the intermediate, deionized water, sodium lignin sulfonate, hydrogen peroxide, and ascorbic acid is 8.1 g: 100 mL: 32.7 g: 2.18 g: 0.654 g.

8. The high-capacity lead paste according to claim 5, characterized in that: In step A3, the usage ratio of thiolated sodium lignin sulfonate, water, silver nitrate aqueous solution, and sodium borohydride aqueous solution is 9 g: 100 mL: 100 mL: 20-25 mL.

9. The method for preparing a high-capacity lead paste according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step S1: Add lead powder, sulfuric acid, short fibers, graphite, xanthan gum, and modified sodium lignin sulfonate into a paste mixer and stir for 5-10 minutes; then add water into the paste mixer and stir for 5-9 minutes; Step S2: Add sulfuric acid to the paste mixer while stirring. The time for adding sulfuric acid is 16-20 minutes, and the temperature for adding sulfuric acid is 57°C-60°C. After the addition of sulfuric acid is completed, continue stirring for 10-15 minutes to obtain high-capacity lead paste. When the temperature of the high-capacity lead paste is lower than 45°C, the paste can be taken out for coating the board.

10. Use of the high-capacity lead paste according to any one of claims 1 to 8 in a lead-acid battery.

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