KR20160122997A - Ionic liquid for lead-acid battery and electrolyte for lead-acid battery containing the same and lead-acid battery containing the same - Google Patents

Abstract

Disclosed are an ionic liquid for a lead-acid battery, an electrolyte for a lead-acid battery containing the ionic liquid, and a lead-acid battery containing the electrolyte. The ionic liquid for a lead-acid battery is added to an electrolyte for a lead-acid battery including distilled water and sulfuric acid (H_2SO_4), and comprises distilled water, magnesium sulfate (MgSO_4), and Ethylenediaminetetraacetic acid disodium salt (EDTA-2Na). Furthermore, the electrolyte for a lead-acid battery comprises the ionic liquid for lead-acid battery, and the lead-acid battery comprises the electrolyte for a lead-acid battery.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ionic liquid for a lead-acid battery, an electrolytic solution for a lead-acid battery including the same, and a lead-acid battery including the same. BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

More particularly, the present invention relates to an ionic liquid added to an electrolytic solution of a lead-acid battery, an electrolytic solution for a lead-acid battery including such an ionic liquid, and a lead-acid battery including such an electrolytic solution for a lead-acid battery.

Approximately 5 billion waste batteries are produced annually worldwide, of which approximately 750 million waste batteries, approximately 15%, are dumped throughout the globe to contaminate the soil and atmosphere. Lead-Acid Battery is a rechargeable secondary battery that consumes about 30 million or more batteries per year in Korea. The amount of lead-acid batteries used is increasing year by year, and about 70 to 80% of rechargeable batteries are being abandoned. to be.

1 is a schematic view showing the structure of a lead-acid battery.

Referring to FIG. 1, a lead-acid battery is generally composed of six cells, each cell having two lead electrodes, and the lead electrodes are plate-shaped and the two lead electrodes are separated into plastic or rubber plates. The lead electrode is exposed to dilute sulfuric acid (H ₂ SO ₄ ), which is lead acid battery electrolyte, and the external electrode terminal is electrically connected to the lead electrode. The hole that is blocked by the stopper can supply water to the lead battery electrolyte and the gas generated by the chemical reaction can escape.

The chemical changes of the lead acid battery are changed to lead sulfate (PbSO ₄ ) in the case of lead dioxide (PbO ₂ ) of the anode, lead (Pb) of the anode, and diluted sulfuric acid (H2SO4) Water (H ₂ O) is produced in the electrolytic solution. In the case of charging, on the contrary, the original plate and dilute sulfuric acid (H2SO4) is. These chemical reaction equations are as follows.

[Anode]: E ₀ = -0.355 V

Pb + SO4 ^{2 -} ↔ PbSO4 + 2e ^-

[Cathode]: E ₀ = 1.70 V

PbO ₂ + SO ₄ ^{2 -} + 4H ⁺ + 2e ^- ↔PbSO ₄ + 2H ₂ O

PbO ₂ + Pb + 2H ₂ SO ₄ ↔ 2PbSO ₄ + 2H ₂ O

When the charge-discharge procedure of a lead acid battery is repeatedly lead sulfate (PbSO ₄₎ in the discharge process it does not completely decomposed when the lead sulfate (PbSO ₄₎ are determined to form a film on the electrode. Sulfate was used to form a lead sulfate ^{_{(PbSO 4) (SO 4 2-}} ) is again sulfuric acid (H ₂ SO ₄₎ did not get to return the fewer and sulfuric acid around the electrode active material (H ₂ SO ⁴⁾ becomes lean. Therefore, lead sulphate (PbSO ₄ ) formed on the electrode lowers the voltage of the lead-acid battery, and the flow of the current is reduced, thereby deteriorating the performance of the lead-acid battery.

In order to solve this problem, there is a method of overcharging a lead acid battery by a method for removing lead sulfate (PbSO ₄ ) formed on a lead battery electrode, and a method of charging a lead battery by a pulse-current charging method. There is a problem that the electrode of the lead-acid battery can be physically damaged.

Accordingly, the inventors of the present invention have invented an ionic liquid for a lead-acid battery and an electrolyte solution for a lead-acid battery including the lead-acid battery, which can maintain the performance of the lead-acid battery in a chemical manner without physically damaging the electrode of the lead-acid battery.

An object of the present invention is to provide an ionic liquid for a lead-acid battery which can prolong the lifetime of the lead-acid battery and maintain the performance of the lead-acid battery, an electrolyte solution for such lead-acid battery, and an electrolyte solution for such lead- A lead-acid battery.

In order to solve the above problems, an ionic liquid for a lead-acid battery which is added to an electrolytic solution for a lead-acid battery including distilled water and sulfuric acid (H ₂ SO ₄ ) according to an embodiment of the present invention includes distilled water; Magnesium sulfate (MgSO _4); And disodium ethylenediaminetetraacetic acid (EDTA.2 Na).

The electrolyte for the lead-acid battery according to another embodiment of the present invention may include the ionic liquid for the lead-acid battery.

In one embodiment, the amount of magnesium sulfate (MgSO ₄ ) is 1 to 5 wt% and the amount of disodium ethylenediaminetetraacetate (EDTA · 2Na) is 1 to 5 wt% based on the total weight of the electrolytic solution for lead acid battery .

In one embodiment, the magnesium sulfate (MgSO ₄ ) is 2.5% by weight based on the total weight of the electrolytic solution for the lead-acid battery, and the sodium disodium ethylenediamine acetic acid (EDTA · 2Na) is 2.5% by weight have.

In one embodiment, the sulfuric acid (H ₂ SO ₄ ) is 21.5% by weight based on the total weight of the electrolytic solution for the lead-acid battery.

The lead acid battery according to another embodiment of the present invention may include the electrolyte for the lead acid battery.

The present invention can prevent deterioration of the performance of the lead-acid battery due to the formation of lead sulfate (PbSO ₄ ) by chemically removing or ionizing the lead sulfate (PbSO ₄ ) formed on the lead electrode surface of the lead-acid battery , The lead electrode (PbSO ₄ ) formed on the lead electrode surface is removed or ionized, thereby prolonging the life of the lead electrode.

Further, the present invention can prevent deterioration of the performance of the lead-acid battery by replenishing the consumed electrolyte in accordance with repetition of charging and discharging of the lead-acid battery.

The invention also harmful sulfur dioxide to the human body caused by a sulfuric acid (H ₂ SO ₄₎ boiling due to high boiling point of the sulfuric acid (H ₂ SO ₄₎ compared with the electrolytic solution for the conventional lead-acid batteries by incorporating an ionic liquid for a lead acid battery ( SOx) can be reduced.

1 is a schematic view showing the structure of a lead-acid battery.
FIG. 2A is a graph showing the content of lead monoxide (PbO) in Examples 1 to 5 over time.
FIG. 2B is a graph showing the content of lead monooxide (PbO) in Examples 5 to 10 over time.
3A is a graph showing a change in surface component of a new lead electrode according to time in Experimental Example 1. FIG.
FIG. 3B is a graph showing changes in the surface component of the waste lead electrode according to the time of Experimental Example 6. FIG.
4 is a graph showing the lead (Pb) content of the lead electrode for each of the charge and discharge test examples 11 to 15.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. Wherein like reference numerals refer to like elements throughout.

Embodiment the ionic liquid for a lead acid battery according to an embodiment of the present invention is purified water, magnesium sulfate (MgSO ₄₎ and ethylene Guardia Civil acid include sodium (EDTA · 2Na).

Magnesium sulfate (MgSO ₄ ) and disodium ethylenediaminetetraacetate (EDTA · 2Na) were added to distilled water to prepare an ionic liquid for a lead-acid battery according to an embodiment of the present invention. The respective weight percentages for disodium magnesium sulfate and disodium ethylenediaminetetraacetate (EDTA · 2Na) can be determined in consideration of the total weight of the electrolytic solution for the lead-acid battery including the ionic liquid for the lead-acid battery according to the embodiment of the present invention, A detailed explanation of this is given below.

The electrolytic solution for a lead-acid battery according to another embodiment of the present invention includes distilled water, sulfuric acid (H ₂ SO ₄ ), magnesium sulfate (MgSO ₄ ), and disodium ethylenediamine acetic acid (EDTA · 2Na). Sulfuric acid (H ₂ SO ₄ ) is added to distilled water to prepare a sulfuric acid solution. For example, a sulfuric acid solution is prepared while controlling the specific gravity of the sulfuric acid (H ₂ SO ₄ ) solution to be about 1.26 to 1.28.

Next, magnesium sulfate (MgSO ₄ ) and disodium ethylenediaminetetraacetic acid (EDTA · 2Na) are added to the sulfuric acid solution to prepare an electrolytic solution for a lead-acid battery according to another embodiment of the present invention. For example, the weight percentage of sulfuric acid (H ₂ SO ₄ ) is set to 21.5 wt% based on the total weight of the electrolytic solution for a lead-acid battery according to an embodiment of the present invention, and the weight percentage of magnesium sulfate (MgSO ₄ ) 2.5% by weight based on the total weight of the electrolytic solution for a lead-acid battery according to the embodiment, and ethylenediamine disodium acetic acid (EDTA · 2Na) is 2.5% by weight based on the total weight of the electrolytic solution for a lead- Weight%.

Disodium ethylenediaminetetraacetic acid (EDTA · 2Na) contained in the electrolytic solution for a lead-acid battery according to another embodiment of the present invention removes or ionizes the lead sulfate (PbSO ₄ ) formed on the lead electrode surface of the lead acid battery, PbSO ₄ ) can be prevented from deteriorating in performance of the lead-acid battery. Also, by removing or ionizing the lead sulfate (PbSO ₄ ) formed on the lead electrode surface, it is possible to extend the service life of the lead electrode.

Further, magnesium sulfate (MgSO ₄ ) contained in the electrolyte for the lead-acid battery according to another embodiment of the present invention replenishes the electrolyte consumed by repeated charging and discharging of the lead-acid battery, thereby preventing deterioration of the performance of the lead-acid battery.

The electrolytic solution for a lead acid battery according to another embodiment of the present invention includes an ionic liquid for a lead acid battery including distilled water, magnesium sulfate (MgSO ₄ ), and disodium ethylenediaminetetraacetic acid (EDTA · 2Na) The boiling point of sulfuric acid (H ₂ SO ₄ ) is higher than that of the electrolytic solution, so that the generation of sulfur dioxide (SOx) harmful to the human body caused by boiling sulfuric acid (H ₂ SO ₄ ) can be reduced.

1. Experiment 1: Disodium ethylenediaminetetraacetate ( EDTA ·2 Na ) Of lead sulfate ( PbSO ₄ ) Removal effect experiment

Preparation of Experimental Solutions 1 to 5

Manufacture of secondary distilled water

The water vapor generated by heating the water is cooled and condensed to obtain the first distilled water, and the second distilled water having passed through the reverse osmosis system or the ion exchange resin can be produced.

Experimental solution 1

50 g of disodium ethylenediaminetetraacetic acid (EDTA.2Na) was added to the second distilled water prepared according to the second distilled water production method to prepare a total of 1 liter (liter) of 5% by weight of disodium ethylenediaminetetraacetic acid (EDTA.2Na) ) Was prepared.

Experimental solution 2

51 ml of a 98% sulfuric acid (H ₂ SO ₄ ) solution was added to the second distilled water prepared according to the above-mentioned second distilled water production method, and a total of 1 liter (ℓ) of sulfuric acid (H ₂ SO ₄ ) Solution 2 was prepared.

Experimental solution 3

50 g of sodium sulfate (Na ₂ SO ₄ ) was added to the second distilled water prepared according to the second distilled water production method to prepare a total 1 liter (l) of Experimental Solution 3 containing 5 wt% of sodium sulfate (Na ₂ SO ₄ ) .

Experimental solution 4

The secondary distilled water and two ammonium sulfate in deionized water manufactured according to the manufacturing method ((NH4) ₂ SO ₄₎ was added to 50g and ammonium sulfate ((NH4) ₂ SO ₄₎ 5% by weight of the total of 1 liters (ℓ) Experimental Solution 4 was prepared.

Experimental solution 5

50 g of magnesium sulfate (MgSO ₄ ) was added to the second distilled water prepared according to the second distilled water production method to prepare a total 1 liter (l) of Experimental Solution 5 containing 5% by weight of magnesium sulfate (MgSO ₄ ).

Experimental Examples 1 to 5 were prepared by injecting each of Experimental Solutions 1 to 5 into five beakers into which new lead electrodes were respectively put into each of the five beakers into which the waste lead electrodes were put, To 5 were added to prepare Experimental Examples 6 to 10. The new lead electrode is a lead electrode for use in the production of lead acid batteries, that is, an unused lead electrode, and the lead solder electrode is a lead electrode that is separated from the lead battery when the life of the lead is discarded.

FIG. 2A is a graph showing the content of lead monoxide (PbO) according to time in Examples 1 to 5, and FIG. 2B is a graph showing a content of lead monoxide (PbO) according to time in Examples 5 to 10.

Referring to FIGS. 2A and 2B, in the case of the new lead electrode, the lead (Pb) content change was least measured in Experimental Example 2 and Experimental Example 5. It is considered that there is no change in the lead (Pb) content on the lead electrode surface even after 28 days since the crystal stabilization by the sulfate ion (SO ₄ ^{2 -} ) proceeds on the surface of the lead electrode at the beginning.

In the case of the new lead electrode, in Example 1, the amount of lead (Pb) was greatly changed from the beginning, and after about 28 days, the content of lead (Pb) was reduced to about 65%. This is due to the fact that sodium ethyldiamineacetate (EDTA · 2Na) acts as a chelating agent with lead (Pb), lead (Pb) on lead electrode surface dissociates disodium ethylenediamine acetic acid (EDTA · 2Na) (Pb) and disodium ethylenediaminetetraacetic acid (EDTA · 2Na) form a complex. Also, in the case of the waste lead electrode, it was confirmed that the content of lead (Pb) in Experimental Example 6 decreased about 7% after about 28 days.

The performance of the lead-acid battery can be divided into the electrode part, the electrolyte part and the cell part. Particularly, the electrode part is deteriorated in the performance of the lead-acid battery due to the influence of the lead sulfate (PbSO ₄ ) . Therefore, it can be confirmed that disodium ethylenediaminetetraacetic acid (EDTA · 2Na) is effective for removing or ionizing lead sulfate (PbSO ₄ ) formed on the lead electrode surface.

FIG. 3A is a graph showing changes in surface component of new lead electrode according to time in Experimental Example 1, and FIG. 3B is a graph showing change in surface component of the lead electrode in the lead electrode according to Experimental Example 6.

3A and 3B, the lead (Pb) content tends to decrease with time in both of Experimental Example 1 and Experimental Example 6, and the decrease in the lead (Pb) content in Test Example 1 . This is because lead sulfate (PbSO ₄ ) is not formed on the surface of new lead electrode, lead (Pb) or lead monoxide (PbO) present on the surface of lead electrode is chelated with disodium ethylenediaminetetraacetic acid (EDTA · 2Na) This is because it is easy to proceed. On the contrary case, the waste lead electrode surface as compared to the new lead electrode of the waste lead electrode lead (Pb), monoxide, lead (PbO) and lead sulfate (PbSO ₄₎ this will be present, lead sulfate (PbSO ₄₎ ethylene to remove or ionizing (Pb) content in Experimental Example 6 is smaller than that in Experimental Example 1, since disodium disacinic acid acetic acid (EDTA · 2Na) acts. In addition, it was confirmed that tin (Sn) compound appeared as time passed in both Experimental Example 1 and Experimental Example 6. [ It was confirmed that tin (Sn) was added at the preparation of the lead electrode, which was detected at 2 weeks for Experimental Example 1 and 3 weeks for Experimental Example 6. This is because, when a certain period of time elapses, sodium EDTA · 2Na (EDTA · 2Na) forms a complex with metals other than lead (Pb), and thus it is inferred that both new lead electrodes and waste lead electrodes can be regenerated And it can be deduced that the disodium ethylenediaminetetraacetic acid (EDTA · 2Na) forms a complex with tin (Sn) to help dissolve the lead sulfate formed on the electrode plate.

2. Experiment 2: Experiment of electrolytic solution of lead-acid battery

Preparation of Experimental Solutions 6 to 10

Experimental solution 6

First, distilled water was obtained by cooling and condensing the water vapor generated by heating the water. Secondary distilled water passed through the reverse osmosis system or ion exchange resin was used as Experiment Solution 6.

Experimental solution 7

Sulfuric acid (H ₂ SO ₄ ) was added to the second distilled water prepared by the method for preparing the second distilled water to prepare Experimental Solution 7 so that the sulfuric acid (H ₂ SO ₄ ) was 21.5 wt% .

Experimental solution 8

Sulfuric acid (H ₂ SO ₄ ) and disodium ethylenediaminetetraacetic acid (EDTA · 2Na) were added to the second distilled water prepared by the method of producing the second distilled water, and sulfuric acid (H ₂ SO ₄ ) Experimental solution 8 was prepared so that the amount of disodium ethylenediaminetetraacetic acid (EDTA · 2Na) was 21.5% by weight based on the weight of the test solution 8, which was 2.5% by weight based on the total weight of the test solution 8.

Experimental solution 9

It said second sulfuric acid in a secondary distilled water prepared in the manner of producing the distilled water (H ₂ SO _4), ethylene dia civil acid disodium (EDTA · 2Na) and magnesium sulfate was added to (MgSO ₄₎ sulfuric acid (H ₂ SO ₄ ) Is 21.5% by weight based on the total weight of the test solution 9, 2.5% by weight based on the total weight of the test solution 9 of disodium ethylenediaminetetraacetic acid (EDTA. 2Na) and magnesium sulfate (MgSO ₄ ) Experimental solution 9 was prepared so as to have a weight of 2.5% by weight.

Experimental solution 10

Sulfuric acid (H ₂ SO ₄ ) and magnesium sulfate (MgSO ₄ ) were added to the secondary distilled water prepared by the method of producing the secondary distilled water, and sulfuric acid (H ₂ SO ₄ ) % And magnesium sulfate (MgSO ₄ ) were prepared to be 2.5% by weight based on the total weight of the test solution 10.

Experimental Examples 11 to 15 were prepared by injecting Experimental Solutions 6 to 10 into five lead acid batteries, respectively, and Experimental Examples 11 to 15 were respectively charged and discharged.

4 is a graph showing the lead (Pb) content of the lead electrode for each of the charged and discharged Experimental Examples 11 to 15.

Referring to FIG. 4, in the case of Experimental Example 11 using only distilled water as an electrolytic solution, dissociation of lead (Pb) proceeded to confirm that lead (Pb) content was the least. In the case of Experimental Example 14, it was confirmed that the reduction of the lead (Pb) content was about 2 to 3%, and in the case of Experimental Example 12, Experimental Example 13 and Experimental Example 15, the lead (Pb) . In addition, in Experimental Example 12 containing only sulfuric acid (H ₂ SO ₄ ), lead sulfate (PbSO 4) was formed on the surface of the lead electrode. Therefore, it can be deduced that the content of lead (Pb) is hardly changed. The reduction of the lead (Pb) content in Experimental Example 14 is greater than that of Experimental Example 12, Experimental Example 13 and Experimental Example 15, because the disodium ethylenediaminocyacetate (EDTA · 2Na) It is considered that magnesium sulfate (MgSO ₄ ) ionizes the lead sulfate (PbSO ₄ ), while it replenishes the electrolyte, for example, sulfate ion (SO ₄ ^2- ), which becomes deficient due to charge and discharge of the lead battery electrolyte.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims. Accordingly, the true scope of the present invention should be determined by the following claims.

Claims (6)

1. An ionic liquid for a lead-acid battery which is added to an electrolytic solution for a lead-acid battery containing distilled water and sulfuric acid (H ₂ SO ₄ )
Distilled water;
Magnesium sulfate (MgSO _4); And
An ionic liquid for lead-acid batteries, comprising disodium ethylenediaminacetate (EDTA. 2Na).
An electrolytic solution for a lead-acid battery comprising the ionic liquid for a lead-acid battery of claim 1.
3. The method of claim 2,
Wherein the magnesium sulfate (MgSO ₄ ) is contained in an amount of 1 to 5 wt% based on the total weight of the electrolytic solution for the lead-acid battery, and the amount of disodium ethylenediaminetetraacetic acid (EDTA · 2Na) is 1 to 5 wt% Electrolytic solution for battery.
3. The method of claim 2,
Wherein the magnesium sulfate (MgSO ₄ ) is 2.5% by weight based on the total weight of the electrolytic solution for the lead-acid battery, and the sodium disodium ethylenediamine acetic acid (EDTA · 2Na) is 2.5% by weight.
5. The method of claim 4,
Wherein the sulfuric acid (H ₂ SO ₄ ) is 21.5% by weight based on the total weight of the electrolytic solution for the lead-acid battery.
A lead-acid battery comprising an electrolyte for a lead-acid battery according to any one of claims 2 to 5.

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