Ultralow-temperature-resistant storage battery negative electrode lead paste and preparation method thereof

Abstract

The invention relates to an ultralow-temperature-resistant storage battery negative electrode lead paste and a preparation method thereof. The ultralow-temperature-resistant storage battery negative electrode lead paste comprises the following components in parts by weight: 1000 parts of lead powder; 80 to 100 parts of sulfuric acid; 80 to 100 parts of water; 0.5 to 1.5 parts of short fibers; 5.0 to 15.0 parts of superfine barium sulfate; 1.2 to 11.0 parts of a conductive additive; 0.4 to 12.0 parts of a polymer; 0.1 to 3.0 parts of sodium dodecyl benzene sulfonate; 2.0 to 6.0 parts of humic acid; 2.0 to 6.0 parts of lignin; according to the invention, the stable composite polymer is introduced as a support body, so that the shrinkage of the polar plate can be effectively resisted at-40 DEG C or below, and a pore structure required by reaction is maintained, so that the battery can still keep effective discharge at extremely low temperature; the conductive performance of the superconducting carbon black-double-layer graphene-nano silver powder composite conductive system is obviously superior to that of a traditional material, and more importantly, a stable three-dimensional conductive framework is formed by functional complementation of all the components.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of storage battery production, and in particular to a super-low-temperature-resistant negative lead paste for storage batteries and a preparation method thereof. BACKGROUND

[0002] The negative electrode formula of a storage battery mainly comprises barium sulfate, lignin, humic acid, short fibers, carbon materials, graphite materials, trace amounts of hydrogen evolution inhibiting materials, etc. The purpose of adding these materials is to improve the strength, conductivity, shrinkage, and sulfuric acid crystallization degree of the negative plate. The mainstream technology for improving the low-temperature performance of the storage battery is to change the amount and physical parameters of these commonly used materials in the negative electrode, especially lignin, humic acid, carbon, and graphite materials. However, these materials are damaged to some extent or even lose their original functions due to decomposition and denaturation when they are subjected to high temperatures and electrochemical states during the production of the battery. On the other hand, when the battery is subjected to super-low temperature, i.e., below -40℃, the sponge-like lead structure of the negative electrode shrinks intensively, making it difficult for the inner active material to contact sulfuric acid and thus unable to effectively discharge, and the outer lead sulfate crystallizes too densely, further hindering the contact between sulfuric acid and the inner active material. Therefore, a super-low-temperature-resistant negative lead paste for storage batteries is proposed to solve this problem. SUMMARY

[0003] In view of the deficiencies in the prior art, the present application provides the following technical solutions: A super-low-temperature-resistant negative lead paste for storage batteries comprises the following components in parts by weight: 1000 parts of lead powder; 80-100 parts of sulfuric acid; 80-100 parts of water; 0.5-1.5 parts of short fibers; 5.0-15.0 parts of ultra-fine barium sulfate; 1.2-11.0 parts of conductive additives; 0.4-12.0 parts of composite polymers; 0.1-3.0 parts of sodium dodecylbenzenesulfonate; 2.0-6.0 parts of humic acid; and 2.0-6.0 parts of lignin.

[0004] As an improvement of the above technical solution, the conductive additives comprise super-conductive carbon black, double-layer graphene, and nano-silver powder, and the mass ratio of the super-conductive carbon black, double-layer graphene, and nano-silver powder is (0.1 ~ 3) : (1 ~ 3) : (0.1~ 5).

[0005] As an improvement of the above technical solution, the particle size of the double-layer graphene is 0.1-1.0 μm, the resistivity of the super-conductive carbon black is 0.8-1.0 Ω*m, the apparent specific volume is 4.0-5.0 cm3 / g, the silver content of the nano-silver powder is 99.99%, and the particle size is less than 100 nm.

[0006] As the improvement of the above technical scheme, the composite polymer comprises polystyrene, polyvinyl chloride, polypropylene and polyethylene, and the mass ratio of the polystyrene, polyvinyl chloride, polypropylene and polyethylene is (0.1-3):(0.1-3):(0.1-3):(0.1-3).

[0007] As the improvement of the above technical scheme, the particle size of the polyvinyl chloride, polystyrene, polypropylene and polyethylene is 1-1000 mu m.

[0008] In addition, the application provides a method for preparing the negative lead paste of the ultra-low temperature resistant storage battery. S1: first, lead powder, short fibers, ultra-fine barium sulfate humic acid and lignin are added into a vacuum stirring kettle, and after stirring for 5 minutes; S2: after adding 80% water, continue to stir for 5 minutes; S3: the conductive carbon black, double-layer graphene, polystyrene, polyvinyl chloride, polypropylene, polyethylene, sodium dodecyl benzene sulfonate, nano-silver powder and the remaining 20% water are uniformly stirred in advance, then are added into the kettle, stirred for 5 minutes, then sulfuric acid is slowly added for about 10 minutes, and finally stirred for 15 minutes to obtain the negative lead paste.

[0009] As the improvement of the above technical scheme, the apparent density of the negative lead paste is 4.40-4.50 g / mL, and the water loss rate is 9.0%-12.0%.

[0010] The application has the following beneficial effects: The application can effectively resist the shrinkage of the plate below-40 DEG C by introducing the composite polymer as the support, maintain the required pore structure of the reaction, and make the battery still maintain effective discharge under the extreme low temperature. The composite conductive system of the application, i.e. the "super-conductive carbon black-double-layer graphene-nano-silver powder", not only has the conductive performance significantly better than the traditional materials, but also more importantly, the functions of the components are complementary to form a stable three-dimensional conductive framework, the carbon black constructs the basic network, the graphene provides the high-speed channel, and the nano-silver powder strengthens the key nodes, which ensures that even after the dense lead sulfate covering layer is formed, the electrons can still be efficiently led out from the deep layer of the plate, and the active material utilization rate is significantly improved. The sodium dodecyl benzene sulfonate is distributed between the interfaces of the micro-plastic-lead paste, the lead paste-lead paste and the lead paste-separator, effectively reduces the surface tension of the sulfuric acid solution, significantly improves the wettability and flowability of the sulfuric acid when the viscosity of the sulfuric acid is sharply increased at low temperature, promotes the electrolyte to more uniformly and deeply penetrate into the three-dimensional porous structure maintained by the micro-plastic skeleton, guarantees the sufficient supply of HSO4⁻ ions, avoids the rapid densification of lead sulfate caused by the reaction concentrated on the surface, and further improves the overall discharge capacity. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 Results of 15 min r cycle life test for example 2 and comparative example 4. DETAILED DESCRIPTION

[0012] In order to make the objects, technical solutions and advantages of the present application clearer, further detailed description will be made to the present application in combination with examples. It should be understood that the specific examples described herein are only used to explain the present application and not used to limit the present application.

[0013] The present application provides a super-low-temperature-resistant negative lead paste for storage batteries, so as to solve the problem that the material is damaged to a certain extent or even loses the original function due to decomposition and degeneration when the material encounters high temperature and electrochemical state of charging and discharging in the production stage of the battery; meanwhile, when the battery is in super-low temperature, i.e. below-40℃, the negative lead sponge structure shrinks intensively, which causes the inner active material to be difficult to contact with sulfuric acid and unable to effectively discharge, and the outer lead sulfate crystal is too dense to further hinder the contact between sulfuric acid and the inner active material. The present application constructs a three-dimensional support skeleton through a composite polymer. When the temperature is reduced to below-40℃, the lead matrix shrinks due to thermal expansion and contraction effect, and the micro-plastic network in the formula acts as a physical support skeleton, which can effectively "support" the micro-pore channels of the plate to prevent the pores from collapsing and closing, thereby reserving key space for the storage and transmission of electrolyte and maintaining the structural integrity of the reaction interface at low temperature. Through a composite conductive system, global electron conduction is realized. The super-conductive carbon black, double-layer graphene and nano-silver powder complement each other in function and jointly construct a global, efficient and stable conductive system. The super-conductive carbon black, as a basic conductive additive, is closely adsorbed and filled between lead particles due to its high specific surface area and porous structure, forming a dense basic conductive network, which significantly reduces the internal resistance of the lead paste. The pore structure can also adsorb and store a small amount of sulfuric acid, locally increasing the concentration of reactants. The double-layer graphene, as a two-dimensional conductive bridge, is adsorbed on the surface of carbon black, lead paste and micro-plastic due to its excellent conductive performance, and constructs an electronic "highway" between particles, effectively relieving the increase in internal resistance caused by the addition of non-conductive materials. The nano-silver powder, with metal-level conductivity, is embedded in the key position of the conductive network, forming a strong conductive core, which ensures that the electrons generated by the deep active material of the plate can still be effectively collected and led out even under the lead sulfate cover layer. At the same time, sodium dodecyl benzene sulfonate is distributed in the interface between microplastic-lead paste, lead paste-lead paste and lead paste-separator, effectively reduces the surface tension of sulfuric acid solution, significantly improves its wettability and fluidity when the viscosity of sulfuric acid increases sharply at low temperature, promotes the electrolyte to penetrate more uniformly and deeply into the three-dimensional porous structure maintained by the microplastic skeleton, ensures sufficient supply of HSO4-ions, avoids rapid densification of lead sulfate caused by reaction concentration on the surface, and further improves the overall discharge capacity.

[0014] Example 1 1000 parts of lead powder; 80 parts of sulfuric acid; 100 parts of water; 0.5 parts of short fiber; 15.0 parts of superfine barium sulfate; 1.2 parts of conductive additive; 0.4 parts of composite polymer; 3.0 parts of sodium dodecyl benzene sulfonate, 2.0 parts of humic acid; 6.0 parts of lignin, The conductive additive includes 0.1 part of super-conductive carbon black, 3 parts of double-layer graphene and 0.1 part of nano-silver powder; The double-layer graphene has a particle size of 0.1 μm, the super-conductive carbon black has a resistivity of 1.0 Ω*m and a apparent specific volume of 4.0 cm3 / g, and the nano-silver powder has a silver content of 99.99% and a particle size of less than 100 nm; The composite polymer includes 0.1 part of polystyrene, 3 parts of polyvinyl chloride, 0.1 part of polypropylene and 3 parts of polyethylene; The above-mentioned lead powder, short fiber, superfine barium sulfate, humic acid, lignin are added into a vacuum stirring kettle, stirred for 5 min, then 80% of water is added, stirred for 5 min, the conductive carbon black, double-layer graphene, polystyrene, polyvinyl chloride, polypropylene, polyethylene, sodium dodecyl benzene sulfonate, nano-silver powder and the remaining 20% of water are pre-stirred uniformly, then added into the kettle, stirred for 5 min, then sulfuric acid is slowly added for about 10 min, finally stirred for 15 min to obtain the negative lead paste, the apparent density of the negative lead paste is 4.40 g / mL, and the water loss rate is 9.0%.

[0015] Example 2 1000 parts of lead powder; 90 parts of sulfuric acid; 90 parts of water; 1 part of short fiber; 10 parts of superfine barium sulfate; 6 parts of conductive additive; 6 parts of composite polymer; 2 parts of sodium dodecyl benzene sulfonate, 4 parts of humic acid; 4 parts of lignin, The conductive additive includes 1.5 parts of super-conductive carbon black, 2 parts of double-layer graphene and 2.5 parts of nano-silver powder; the double-layer graphene has a particle size of 0.5 μm, the super-conductive carbon black has a resistivity of 0.9 Ω*m and an apparent specific volume of 4.5 cm3 / g, and the nano-silver powder has a silver content of 99.99% and a particle size of less than 100 nm; The composite polymer includes 2 parts of polystyrene, 2 parts of polyvinyl chloride, 2 parts of polypropylene and 2 parts of polyethylene; The lead powder, short fibers, superfine barium sulfate, humic acid, and lignin are added into a vacuum stirring kettle, stirred for 5 min, then 80% of the water is added, stirred for 5 min, the conductive carbon black, double-layer graphene, polystyrene, polyvinyl chloride, polypropylene, polyethylene, sodium dodecyl benzene sulfonate, nano-silver powder, and the remaining 20% of the water are uniformly stirred in advance, then added into the kettle, stirred for 5 min, then sulfuric acid is slowly added for about 10 min, finally stirred for 15 min to end, to obtain the negative lead paste, the apparent density of the negative lead paste is 4.45 g / mL, and the water loss rate is 10%.

[0016] Example 3 1000 parts of lead powder; 100 parts of sulfuric acid; 80 parts of water; 1.5 parts of short fibers; 5.0 parts of superfine barium sulfate; 11.0 parts of conductive additive; 12.0 parts of composite polymer; 0.1 part of sodium dodecyl benzene sulfonate, 6.0 parts of humic acid; 2.0 parts of lignin, The conductive additive includes 3 parts of super-conductive carbon black, 1 part of double-layer graphene, and 5 nanometer silver powder. The double-layer graphene has a particle size of 1.0 μm, the super-conductive carbon black has a resistivity of 0.8-1.0 Ω*m and an apparent specific volume of 5.0 cm3 / g, and the nano-silver powder has a silver content of 99.99% and a particle size of less than 100 nm.

[0017] The composite polymer includes 3 parts of polystyrene, 0.1 part of polyvinyl chloride, 3 parts of polypropylene, and 0.1 part of polyethylene. The lead powder, short fibers, superfine barium sulfate, humic acid, and lignin are added into a vacuum stirring kettle, stirred for 5 min, then 80% of the water is added, stirred for 5 min, the conductive carbon black, double-layer graphene, polystyrene, polyvinyl chloride, polypropylene, polyethylene, sodium dodecyl benzene sulfonate, nano-silver powder, and the remaining 20% of the water are uniformly stirred in advance, then added into the kettle, stirred for 5 min, then sulfuric acid is slowly added for about 10 min, finally stirred for 15 min to end, to obtain the negative lead paste, the apparent density of the negative lead paste is 4.45 g / mL, and the water loss rate is 10%.

[0018] Comparative Example 1 The difference from Example 2 is that the conductive additive includes 1.5 parts of super-conductive carbon black and 2 parts of double-layer graphene.

[0019] Comparative Example 2 The difference from Example 2 is that the composite polymer includes 2 parts of polystyrene, 2 parts of polyvinyl chloride, and 2 parts of polypropylene.

[0020] Comparative Example 3 The difference from Example 2 is that no polymer is added. Comparative Example 4 1.0 parts of short fiber, 11 parts of superfine barium sulfate, 3.5 parts of carbon black, 2.0 parts of humic acid, 3.0 parts of lignin, 90 parts of sulfuric acid, 80 parts of water, 1000 parts of lead powder, the above lead powder, short fiber, superfine barium sulfate, humic acid, lignin are added into a vacuum stirred tank, stirred for 5 min, then 80% of water is added, stirred for 5 min, the carbon black and the remaining 20% of water are pre-stirred uniformly, then added into the tank, stirred for 5 min, then sulfuric acid is slowly added for about 10 min, finally stirred for 15 min to end, to obtain a negative lead paste, the density of the lead paste is 4.46 g / mL; the water loss rate of the lead paste is 10.5%; The negative lead paste of examples 1-3 and comparative examples 1-4 is coated, cured, dried to obtain a green plate, the green plate is brushed, assembled, welded into a groove and acidized to form a lead-acid battery for performance testing; The test results are shown in table 1 and table 2:

[0021] Table 1

[0022] Table 2 From table 1, table 2 and Figure 1 It can be seen that examples 1-3 can significantly improve the discharge capacity of the battery in the environment of-40℃ to-20℃, and ensure the high temperature floating life and cycle times, the present application takes into account the ultra-low temperature performance and high temperature life of the battery through the synergistic effect of the conductive additive (super-conductive carbon black, double-layer graphene, nano-silver powder) and the composite polymer, among which, the multi-element synergy of the conductive additive effectively solves the conductive bottleneck at low temperature, and the composite polymer lays a foundation for maintaining the reaction interface and structure stability.

[0023] The above are preferred embodiments of the present application, and are not limited to the protection scope of the present application, therefore: any equivalent changes made according to the structure, shape, principle of the present application shall be covered within the protection scope of the present application.

Claims

1. A lead paste for the negative electrode of an ultra-low temperature resistant storage battery, characterized in that, It comprises the following components by weight: 1000 parts lead powder; 80-100 parts sulfuric acid; 80-100 parts water; 0.5-1.5 parts short fibers; 5.0-15.0 parts ultrafine barium sulfate; 1.2-11.0 parts conductive additives; 0.4-12.0 parts composite polymer; 0.1-3.0 parts sodium dodecylbenzenesulfonate; 2.0-6.0 parts humic acid; and 2.0-6.0 parts lignin.

2. The ultra-low temperature resistant lead paste for the negative electrode of a storage battery according to claim 1, characterized in that: The conductive additive includes superconducting carbon black, bilayer graphene, and nano silver powder, and the mass ratio of the superconducting carbon black, bilayer graphene, and nano silver powder is (0.1 ~ 3): (1 ~ 3): (0.1 ~ 5).

3. The ultra-low temperature resistant lead paste for the negative electrode of a storage battery according to claim 2, characterized in that: The bilayer graphene has a particle size of 0.1–1.0 μm, the superconducting carbon black has a resistivity of 0.8–1.0 Ω*m and an apparent capacitance of 4.0–5.0 cm³ / g, and the nano silver powder has a silver content of 99.99% and a particle size of less than 100 nm.

4. The ultra-low temperature resistant lead paste for the negative electrode of a storage battery according to claim 1, characterized in that: The composite polymer includes polystyrene, polyvinyl chloride, polypropylene, and polyethylene, and the mass ratio of polystyrene, polyvinyl chloride, polypropylene, and polyethylene is (0.1 - 3): (0.1 - 3): (0.1 - 3): (0.1 - 3).

5. The ultra-low temperature resistant lead paste for the negative electrode of a storage battery according to claim 1, characterized in that: The particle size of the polyvinyl chloride, polystyrene, polypropylene, and polyethylene is 1–1000 μm.

6. A method for preparing a lead paste for the negative electrode of an ultra-low temperature resistant storage battery as described in any one of claims 15, characterized in that, Includes the following steps: S1: First, add lead powder, short fibers, ultrafine barium sulfate humic acid, and lignin to a vacuum mixing vessel and stir for 5 minutes; S2: After adding 80% water, continue stirring for 5 minutes; S3: Conductive carbon black, bilayer graphene, polystyrene, polyvinyl chloride, 1 part polypropylene, 1 part polyethylene, sodium dodecylbenzenesulfonate, nano silver powder and the remaining 20% ​​water are pre-stirred evenly, then added to the reactor and stirred for 5 minutes. Then sulfuric acid is slowly added for about 10 minutes and finally stirred for 15 minutes to finish, thus obtaining negative electrode lead paste.

7. The method for preparing a lead paste for the negative electrode of an ultra-low temperature resistant storage battery according to claim 6, characterized in that: The apparent density of the negative electrode lead paste is 4.40–4.50 g / mL, and the water loss rate is 9.0%–12.0%.

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