Lead-acid battery electrolyte additive

Abstract

The present invention discloses a lead-acid battery electrolyte additive, and relates to the technical field of lead-acid batteries and electrolyte preparation. The lead-acid battery electrolyte additive of the present invention comprises, by weight: 20-25 parts of lithium slag powder, 5-7 parts of stannous sulfate, 1-1.5 parts of sodium carboxymethyl cellulose, 0.3-0.8 parts of cerium hydroxide, 3-5 parts of lauryl phosphate, 0.8-1.4 parts of polyacrylamide, and 4-7 parts of gelatin. The present invention uses lithium slag powder as the main raw material, and the lithium slag powder contains highly active amorphous silica and aluminum oxide, supplemented by stannous sulfate, sodium carboxymethyl cellulose, cerium hydroxide, etc. to form an electrolyte additive. The electrolyte prepared by using the additive of the present invention can greatly weaken its own local density change rate during the battery charge and discharge process, thereby significantly delaying the stratification phenomenon of the electrolyte, and ultimately achieving the advantages of improving battery performance and service life.

Description

Technical Field

[0001] The invention belongs to the technical field of lead-acid batteries and electrolyte preparation, and particularly relates to an electrolyte additive for lead-acid batteries. Background Art

[0002] Today, large-scale industrialized batteries mainly include lead-acid batteries, nickel-cadmium batteries, nickel-hydrogen batteries and lithium-ion batteries. Among them, lead-acid batteries are still the most important secondary batteries due to their advantages such as low unit energy price, high recycling value, low overall cost and mature technology, and are widely used in many fields.

[0003] Lead-acid batteries primarily use lead dioxide as the positive electrode, sponge lead as the negative electrode, and aqueous sulfuric acid as the electrolyte. Aqueous sulfuric acid is a mixture of H2SO4 and water. Under the influence of gravity, heavier substances tend to sink. Therefore, when left standing, H2SO4 will precipitate and concentrate downward, causing the electrolyte to stratify. During actual charge and discharge, lead-acid batteries generate H2SO4 during charging and water during discharge, causing the local H2SO4 concentration to fluctuate continuously, accelerating stratification during cycling. The higher the plate height where the electrolyte is present, the more pronounced the stratification. Electrolyte stratification results in different charge and discharge reaction states at different altitudes, causing sulfation and accelerated self-discharge, ultimately reducing battery capacity and shortening battery life. It also affects the battery's low-temperature and high-current performance.

[0004] To address the stratification phenomenon in lead-acid battery electrolytes, colloidal electrolytes are currently commonly used. The gelling agent that makes up the electrolyte forms hydrogen bonds through the hydroxyl groups on its surface, forming a three-dimensional network structure in the system, encapsulating sulfuric acid and water. The gel-based electrolyte effectively prevents sulfuric acid stratification, increases battery discharge stability, and extends battery life. In the prior art, fumed silica is often used as a gelling agent. However, fumed silica is difficult to prepare, has limited varieties, and is expensive. It also contains impurities that impair lead-acid battery performance. The colloidal electrolyte prepared using it also requires a complex process to prepare the battery, which has obvious limitations. In view of this, considering the comprehensive production cost and battery performance, further research on lead-acid battery electrolytes is still needed. Summary of the Invention

[0005] In view of the problems in the practical application of lead-acid batteries mentioned in the background technology and the limitations of the existing technology, the purpose of the present invention is to provide a lead-acid battery electrolyte additive, which aims to overcome the stratification problem of lead-acid battery electrolyte, improve the performance of lead-acid batteries, expand their applicable fields, and enhance their market competitiveness.

[0006] To achieve the above object, the present invention specifically adopts the following technical solutions:

[0007] The present invention provides a lead-acid battery electrolyte additive, which comprises the following raw materials in parts by weight:

[0008] 20-25 parts of lithium slag powder, 5-7 parts of stannous sulfate, 1-1.5 parts of sodium carboxymethyl cellulose, 0.3-0.8 parts of cerium hydroxide, 3-5 parts of lauryl phosphate, 0.8-1.4 parts of polyacrylamide, and 4-7 parts of gelatin.

[0009] Preferably, the electrolyte additive comprises the following raw materials in parts by weight: 24 parts of lithium slag powder, 6 parts of stannous sulfate, 1.4 parts of sodium carboxymethyl cellulose, 0.6 parts of cerium hydroxide, 4 parts of lauryl phosphate, 1.1 parts of polyacrylamide, and 6 parts of gelatin.

[0010] Preferably, the lithium slag powder is obtained by mechanically grinding waste slag after lithium extraction using a lepidolite salt method, and has a particle size of less than 20 μm.

[0011] Preferably, the silicon dioxide content in the lithium slag is 46±2.25%, and the aluminum oxide content is 17±1.05%.

[0012] The present invention also adopts the additive to prepare lead-acid battery electrolyte.

[0013] Preferably, the method for preparing the lead-acid battery electrolyte comprises the following steps:

[0014] Step 1): Accurately weigh the raw materials according to the additive raw material formula ratio;

[0015] Step 2): lithium slag powder, stannous sulfate, cerium hydroxide, and polyacrylamide are put into water for shearing to obtain a lithium slag dispersion for later use;

[0016] Step 3): sodium hydroxymethyl cellulose and lauryl phosphate are added to the lithium slag dispersion obtained in step 2) and stirred thoroughly, and then gelatin and sulfuric acid aqueous solution are added and sheared to obtain an electrolyte.

[0017] Preferably, in step 2), the mass ratio of lithium slag powder to water is 1:30-40.

[0018] Preferably, in step 3), the amount of sulfuric acid aqueous solution added is 120-180 times the mass of the lithium slag powder, and the mass fraction of the sulfuric acid aqueous solution is 45%-55%.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] To address the stratification issues of aqueous sulfuric acid solutions in lead-acid battery electrolytes and the limitations of fumed silica gel coagulants, the present invention uses lithium slag powder as the primary raw material. The lithium slag powder contains highly active amorphous silica and alumina, supplemented with stannous sulfate, sodium carboxymethyl cellulose, cerium hydroxide, and the like to form an electrolyte additive. The additive formulated in the present invention can form an irregular, multi-branched, nanoporous, three-dimensional network gel with high permeability and long gelation time and good stability with the sulfuric acid solution. The resulting electrolyte can significantly reduce its own local density change rate during the battery's charge and discharge process, thereby significantly delaying the stratification of the electrolyte, ultimately achieving the advantages of improved battery performance and service life. DETAILED DESCRIPTION

[0021] To make the objects, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be described clearly and completely below in conjunction with the examples. Where specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or the conditions recommended by the manufacturer. Where the manufacturer of the reagents or instruments is not specified, all are commercially available conventional products.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art in the art. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] Example 1

[0024] An additive for lead-acid battery electrolyte:

[0025] Accurately weigh 24 parts of lithium slag powder, 6 parts of stannous sulfate, 1.4 parts of sodium carboxymethyl cellulose, 0.6 parts of cerium hydroxide, 4 parts of lauryl phosphate, 1.1 parts of polyacrylamide, and 6 parts of gelatin according to weight.

[0026] Example 2

[0027] An additive for lead-acid battery electrolyte:

[0028] Accurately weigh 20 parts of lithium slag powder, 7 parts of stannous sulfate, 1 part of sodium carboxymethyl cellulose, 0.8 parts of cerium hydroxide, 5 parts of lauryl phosphate, 0.8 parts of polyacrylamide, and 7 parts of gelatin according to weight.

[0029] Example 3

[0030] An additive for lead-acid battery electrolyte:

[0031] Accurately weigh 25 parts of lithium slag powder, 5 parts of stannous sulfate, 1.5 parts of sodium carboxymethyl cellulose, 0.3 parts of cerium hydroxide, 3 parts of lauryl phosphate, 1.4 parts of polyacrylamide, and 4 parts of gelatin according to weight.

[0032] The lithium slag used in the present invention is lepidolite slag, the main chemical components of which are shown in Table 1. Before the test, the slag was ground to a particle size of less than 20 μm.

[0033] Table 1 Main components of lepidolite slag

[0034]

[0035] Example 5

[0036] The raw materials were weighed according to the formula ratio of Example 1. First, lithium slag powder, stannous sulfate, cerium hydroxide, and polyacrylamide were put into water 36 times the mass of the lithium slag powder and sheared at high speed to obtain a lithium slag dispersion. Sodium hydroxymethyl cellulose and lauryl phosphate were added to the lithium slag dispersion and stirred thoroughly. Gelatin and a sulfuric acid aqueous solution (52%) 160 times the mass of the lithium slag powder were then added thereto and sheared at high speed to obtain an electrolyte.

[0037] Example 6

[0038] The raw materials were weighed according to the formula ratio of Example 2. First, lithium slag powder, stannous sulfate, cerium hydroxide, and polyacrylamide were put into water 30 times the mass of the lithium slag powder and sheared at high speed to obtain a lithium slag dispersion. Sodium hydroxymethyl cellulose and lauryl phosphate were added to the lithium slag dispersion and stirred thoroughly. Gelatin and a sulfuric acid aqueous solution (52%) 135 times the mass of the lithium slag powder were then added thereto and sheared at high speed to obtain an electrolyte.

[0039] Example 7

[0040] The raw materials were weighed according to the formula ratio of Example 3. First, lithium slag powder, stannous sulfate, cerium hydroxide, and polyacrylamide were put into water 40 times the mass of the lithium slag powder and sheared at high speed to obtain a lithium slag dispersion. Sodium hydroxymethyl cellulose and lauryl phosphate were added to the lithium slag dispersion and stirred thoroughly. Gelatin and a sulfuric acid aqueous solution (52%) 180 times the mass of the lithium slag powder were then added thereto and sheared at high speed to obtain an electrolyte.

[0041] Comparative Example 1

[0042] An electrolyte was prepared according to the additive formulation ratio of Example 1, except that cerium hydroxide was not added, and the step parameters were the same as those of Example 5.

[0043] Comparative Example 2

[0044] Silica sol (SiO2 concentration 35%) is used instead of the lithium slag used in the present invention, and the raw materials are weighed as electrolyte additives according to the formula ratio of Example 1, and the step parameters are the same as those of Example 5 to prepare an electrolyte.

[0045] Test example

[0046] First, the electrolytes prepared in Examples 5-7 and Comparative Examples 1-2 were compared. After 6 hours of infusion, the gelation of the electrolytes was observed. None of Examples 5-7 and Comparative Example 1 formed gel, while Comparative Example 2 did. This indicates that the electrolytes prepared using the additives of the present invention exhibit significantly longer gelation times and better stability.

[0047] The electrolytes prepared in Examples 5-7 and Comparative Example 1 were used to prepare closed lead-acid batteries using the same process parameters. The resulting batteries were subjected to cycle charge and discharge tests and inspections:

[0048] The obtained batteries were subjected to charge and discharge cycles under the same conditions, with charge and discharge twice a day for 5 consecutive months (each test group was divided into two groups with 2A discharge and 10A discharge, and each group was repeated multiple times, and the average value was finally taken). The electrolyte density tests of different test groups at different times are shown in Table 2.

[0049] Table 2

[0050]

[0051] The embodiments described above merely represent several preferred embodiments of the present invention. While the descriptions are relatively specific and detailed, they are not intended to limit the present invention. It should be noted that those skilled in the art will readily appreciate that the present invention is susceptible to various variations and modifications. Any modifications, equivalent substitutions, or improvements within the scope of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A lead-acid battery electrolyte additive, characterized in that The electrolyte additives include the following raw materials in parts by weight: 20-25 parts of lithium slag powder, 5-7 parts of stannous sulfate, 1-1.5 parts of sodium carboxymethyl cellulose, 0.3-0.8 parts of cerium hydroxide, 3-5 parts of lauryl phosphate, 0.8-1.4 parts of polyacrylamide, and 4-7 parts of gelatin; The lithium slag powder is obtained by mechanically grinding the waste slag after lithium extraction by the lepidolite salt method, and its particle size is less than 20 μm. The silicon dioxide content in the lithium slag is 46±2.25%, and the aluminum oxide content is 17±1.05%.

2. The lead-acid battery electrolyte additive according to claim 1, characterized in that The electrolyte additive includes the following raw materials in parts by weight: 24 parts of lithium slag powder, 6 parts of stannous sulfate, 1.4 parts of sodium carboxymethyl cellulose, 0.6 parts of cerium hydroxide, 4 parts of lauryl phosphate, 1.1 parts of polyacrylamide, and 6 parts of gelatin.

3. Use of the additive as claimed in claim 1 or 2 in the preparation of lead-acid battery electrolyte.

4. The application according to claim 3, characterized in that The preparation method of the lead-acid battery electrolyte comprises the following steps: Step 1): Accurately weigh the raw materials according to the additive raw material formula ratio; Step 2): Take lithium slag powder, stannous sulfate, cerium hydroxide, and polyacrylamide and put them into water for shearing to obtain a lithium slag dispersion for later use; Step 3): Add sodium hydroxymethyl cellulose and lauryl phosphate to the lithium slag dispersion obtained in step 2) and stir thoroughly, then continue to add gelatin and sulfuric acid aqueous solution and shear to obtain the electrolyte.

5. The application according to claim 4, characterized in that: Step 2) The mass ratio of lithium slag powder to water is 1:30-40.

6. The application according to claim 4, characterized in that: Step 3) adding a sulfuric acid aqueous solution in an amount of 120-180 times the mass of the lithium slag powder, wherein the mass fraction of the sulfuric acid aqueous solution is 45%-55%.

Images