Slow-release composite additive for AGM start-stop battery and preparation method thereof

Abstract

Slow-release composite additive for AGM start-stop battery and preparation method thereof, characterized in that porous glass microspheres made of natural inorganic non-metallic salts (such as borosilicate, etc.) are used to adsorb the composite additive solution; the composite additive solution is prepared by mutually dissolving anhydrous sodium sulfate, trifluoromethanesulfonic acid, potassium perfluorobutanesulfonate and sulfuric acid solution in a weight ratio of 0.8∶0.1∶0.1∶100; the usage method is to fill the porous microspheres adsorbed with the composite additive in the voids inside the battery: on the one hand, it can slow down the expansion and deformation of the electrode plate during charge and discharge and the softening and shedding of the active material; at the same time, it can also slowly release the solution in the adsorbed state to supplement the loss of the electrolyte during the use of the battery, thereby greatly improving the cycle durability of the AGM start-stop battery.

Description

Technical Field

[0001] The present invention relates to a slow-release composite additive for an AGM start-stop battery and a preparation method thereof, belonging to the field of lead-acid batteries for start-stop applications. Background Art

[0002] Due to its high cost performance, lead-acid batteries play a crucial role in all secondary battery fields. Among all power supply systems with aqueous solutions, lead-acid batteries have a relatively high working voltage, good high-current discharge performance, and high and low-temperature discharge performance. Moreover, it is not only suitable for starting and energy storage, but also applicable as a power battery for cyclic use. Therefore, lead-acid batteries can be widely used in various application fields such as backup power supplies, start-stop power supplies, and power sources.

[0003] Since the invention of lead-acid batteries in the 19th century, more than 160 years have passed, and the technical route and manufacturing level have become increasingly mature. However, there are still some problems restricting the use of start-stop lead-acid batteries. During the use of start-stop lead-acid batteries, since they are always in the process of charging and discharging, they often dry out and fail due to water loss, greatly shortening the service life of the battery. Analyzing the main reason, it is due to overcharging that causes the decomposition of water. The oxygen and hydrogen gas released make the internal pressure of the battery increase, and the start-up exhaust valve discharges the gas out of the battery case, while taking out water and sulfuric acid at the same time. This is one of the main reasons for battery water loss, capacity attenuation, and even life termination. Another important reason for the failure of lead-acid batteries is that during the charging and discharging process, the lead paste on the electrode plate undergoes electrochemical reactions, resulting in expansion and contraction, leading to the sludging and even migration of the lead paste. Seriously, the grid ribs are deformed or even broken under stress, causing the direct contact and short circuit of the positive and negative electrode grids or lead paste, and ultimately damaging the entire battery and terminating its life and scrapping. Summary of the Invention

[0004] The purpose of the present invention is to provide a slow-release composite additive for an AGM start-stop battery that can slow down the softening and deformation of the electrode plate and solve the problem of rapid water loss due to high ambient temperature during use.

[0005] The technical solution of the present invention is: porous glass microspheres made of borosilicate are used to adsorb a composite additive composed of anhydrous sodium sulfate, trifluoromethanesulfonic acid, potassium perfluorobutanesulfonate, and sulfuric acid solution. The diameter of the glass microspheres is between 10 and 50 microns.

[0006] The present invention provides porous glass microspheres for an AGM start-stop battery adsorption composite additive. A glass hollow sphere with a diameter between a few micrometers and several hundred micrometers and having a large number of micropores uniformly distributed within its volume is called a porous glass microsphere, which can be used as a slow-release adsorption material, and its material composition is an inorganic non-metallic salt material that can stably exist in a strong acid medium, such as borosilicate, etc. Adsorb a composite additive (sulfuric acid aqueous solution of anhydrous sodium sulfate, trifluoromethanesulfonic acid, and potassium perfluorobutanesulfonate) with a certain formulation ratio using the glass microspheres, and the density of the sulfuric acid solution is less than or equal to 1.28 g / cm 3 ; the density of the solution adsorbed by the glass microspheres is not greater than the initial density of the electrolyte. Specific implementation method

[0007] Dissolve anhydrous sodium sulfate, trifluoromethanesulfonic acid, and potassium perfluorobutanesulfonate in a sulfuric acid solution of 1.270 g / cm 3 (25 °C), with a weight ratio of 0.8∶0.1∶0.1∶100; at this time, the density of the solution is about 1.278 g / cm 3 (25 °C) or so. Stir during the process and heat to a certain extent if necessary to ensure that the additive is completely dissolved in the sulfuric acid solution; then add a certain amount of porous glass microspheres thereto, stir properly for about 30 min, and then let it stand in a vacuum environment for 1 h to enable the solution to be sufficiently adsorbed in the voids of the glass microspheres.

[0008] Fill the glass microspheres containing the composite additive prepared by the above method in all the voids of 2 start-stop 6-QTF-70 batteries, mark them as "Test 1" and "Test 2", and conduct blank comparative experiments on the other 2 batteries, marked as "Comparison 1" and "Comparison 2". Among them, "Test 1" and "Comparison 1" conduct low-temperature starting ability tests and charge acceptance ability tests; "Test 2" and "Comparison 2" conduct cycle durability tests;

[0009] Detection equipment: Jiangsu Jinfan charge and discharge tester.

[0010] Test temperature: 25 ± 2 °C

[0011] Detection standard: Adopt the requirements of Article 4.4 "Low-temperature starting ability", Article 4.5 "Charge acceptance ability", and Article 4.8 "Cycle durability ability" in GB / T5008.1-2013 "Lead-acid batteries for starting - Part 1: Technical conditions and test methods";

[0012] Detection method: Conduct according to the test methods of Article 5.5 "Low-temperature starting ability", Article 5.6 "Charge acceptance ability", and Article 5.9 "Cycle durability ability" in GB / T5008.1-2013 "Lead-acid batteries for starting - Part 1: Technical conditions and test methods";

[0013] The test results are shown in Table 1 and Table 2 as follows:

[0014] Table 1. Comparison of Test Results of Low-temperature Starting Ability

[0015]

[0016] Table 2. Comparison of Test Results of Charge Acceptance Ability

[0017] Battery Number Test 1 Comparison 1 Charge Acceptance Ability 2.41 2.39

[0018] Table 3. Comparison of Results of Cycle Durability Ability

[0019] Battery Number Test 2 Comparison 2 Cycle Durability Ability 396 times 274 times

[0020] Test Conclusions and Analysis:

[0021] From the test data of "low-temperature starting ability" and "charge acceptance ability" in Table 1 and Table 2, it can be seen that when comparing the battery with the slow-release composite additive added with the blank comparison battery, both its low-temperature performance and charge acceptance ability have been improved, but the improvement amplitude is not obvious, indicating that the addition of the slow-release additive has little impact on its performance in the initial stage of battery use.

[0022] Through the dissection of the batteries of "Test 1" and "Comparison 1" in Table 3, it is found that:

[0023] For the "Comparison 2" battery: obvious problems such as dryness of the separator, softening of the positive plate, and migration of the active material of the negative plate occur;

[0024] For the "Test 2" battery: the degree of softening and shedding of the positive plate and the migration of the negative active material are basically the same as those of the "Comparison 1" battery, and the degree of dryness of the separator is slightly better. Considering that the number of cycles has increased by more than 30%, its cycle durability performance has still been significantly improved.

[0025] The present invention uses porous glass microspheres adsorbed with sulfuric acid solution of anhydrous sodium sulfate, trifluoromethanesulfonic acid and potassium perfluorobutanesulfonate to fill in the start-stop lead-acid battery, which can greatly slow down the dryness of the electrolyte and the softening and shedding of the active material of the electrode plate, so it can greatly improve the service life of the battery. The cycle durability ability has increased by more than 30%, and the low-temperature performance and charge acceptance ability can also be improved to a certain extent, which can greatly improve the market competitiveness of the AGM start-stop battery.

Claims

1. A slow-release composite additive for an AGM start-stop battery, characterized in that Porous glass microspheres are made of borosilicate. The composite additive solution is prepared by mutually dissolving anhydrous sodium sulfate, trifluoromethanesulfonic acid, potassium perfluorobutanesulfonate and sulfuric acid solution in a weight ratio of 0.8:0.1:0.1:

100. The density of the solution adsorbed by the glass microspheres is not greater than the initial density of the electrolyte, and it is filled in the voids inside the start-stop battery.

2. The sustained-release composite additive for AGM start-stop battery according to claim 1, characterized in that The density of the sulfuric acid solution is less than or equal to 1.28 g / cm 3 .

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