WO2007015686A1

WO2007015686A1 - Additive to a positive electrode electrolyte and paste and method for improving characteristics of storage batteries

Info

Publication number: WO2007015686A1
Application number: PCT/UA2006/000011
Authority: WO
Inventors: Mykola Pavlovych Soldatenko; Vitalii Oleksandrovych Kozhukhovskyi; Vitalii Mykolaievych Soldatenko
Original assignee: Mykola Pavlovych Soldatenko; Kozhukhovskyi Vitalii Oleksand; Soldatenko Vitalii Mykolaievyc
Priority date: 2005-08-02
Filing date: 2006-03-15
Publication date: 2007-02-08
Also published as: EA011566B1; EA200800088A1; UA77899C2

Abstract

The invention relates to the electrotechnical industry and can be used for producing and operating lead-acid and alkaline batteries. Said invention excludes the active mass sulfatation, slipping and falling in lead-acid batteries and to eliminate dendrite formation in alkaline batteries associated with a reduced material peeling and falling. The inventive additive to the electrolyte and paste of the positive electrode comprises a distilled water and an ethylenediamine tetraacetic acid tetra or disodium salt, wherein said acid content in the mixture ranges from 0.05 to 99.95 mass %. Said additive is introducible into the electrolyte mainly during a storage battery charging mode.

Description

Positive electrode additive and electrolyte paste and method for improving battery performance

Technical field

The invention relates to electrical engineering and can be used in the manufacture of chemical current sources, as well as in the manufacture and operation of lead-acid and alkaline batteries.

BACKGROUND OF THE INVENTION Typically, a lead-acid battery contains lattice lead plates lowered into a solution of sulfuric acid with a density of 1, 2-1,29 g / cm (28-38 wt.% H ₂ SO ₄ ).

PbO lead oxide is deposited on the plates, and the plates themselves are separated by non-conductive separators. In a solution of sulfuric acid, the surface of the plates is coated with sparingly soluble lead sulfate PbSO ₄ by the reaction:

PbO + H ₂ SO ₄ -> PbSO ₄ + 2H ₂ O

When the lead battery is discharged, the following reactions occur:

Pb + SO ₄ ^" → PbSO ₄ + 2e ^" ,

PbO ₂ + SO ₄ ^{2 '} + 4H ⁺ + 2e ^~ -> PbSO ₄ + 2H ₂ O

As a result of each reaction, an insoluble substance is formed - lead sulfate PbSO ₄ deposited on the plates, which forms a dielectric layer between the down conductors and the active mass. This is one of the disadvantages that affects the life of a lead-acid battery.

The main processes of wear of lead-acid batteries are:

- sulfation of the plates, which consists in the formation of large crystallites of lead sulfate, which prevents the reversal of current-forming processes;

- corrosion of the electrodes, i.e. electrochemical processes of oxidation and dissolution in the electrolyte, which causes shedding of the material of the down conductors; - poor mechanical strength or poor adhesion of the active mass to the down conductors, which leads to the fall of the active mass;

- creep and shedding of the active mass of positive electrodes associated with loosening, violation of uniformity.

5 The main disadvantage of alkaline batteries is the formation of dendrites (tree growths), oxygen evolution and migration, mass transfer of electrodes, swelling during cyclic processes, accompanied by peeling and shedding of the battery materials. To solve these problems and improve the electrical and operational characteristics of batteries, various additives to the electrolyte and battery electrodes have been proposed.

So, for example, an additive to the electrolyte for the regeneration of a lead-acid battery is known, which is introduced into the sulfate 15 electrolyte, including aluminum, cadmium and magnesium sulfates (see Chinese patent N21332483, MPK H01M10 / 08, H01 M10 / 42, 01/23/2002) .

The disadvantages of the known additive are that it increases the concentration of sulfuric acid, which improves the solubility of lead sulfate PbSO ₄ , but enhances the corrosion of down conductors and not 20 prevents the active mass of the electrodes from falling off, and the metal formed as a result of the recovery of cadmium ions changes the potential difference between the electrodes of the battery and also enhances corrosion of down conductors.

Known additive to the electrolyte for lead-acid 25 batteries containing aniline or its salts of mineral acids selected from the group comprising phosphate, sulfate, aniline hydrochloride (USSR patent Ne 1820963, IPC H 01 M 4/20, 07/07/1993).

A disadvantage of the known additive is its limited use only for the process of electrode formation, as well as the uneven deposition of the polymer of the aniline structure, which has a relatively low conductivity.

The lead acid battery electrolyte additive, including aniline or aniline salt of mineral acid, does not active on the electrode, an electrolyte-soluble polydentant ligand and an acid with an activity greater than sulfuric acid partially solves the problems associated with plate sulfation and electrode corrosion, but is a rather complex composition (RF patent 5 Ns 2252468 C2, H01 M10 / 06; H01 M10 / 08, 20.1 1.2004).

Known electrolyte for alkaline batteries and an additive in an electrolyte containing alkali metal hydroxide and distilled water into which polyacrylamide is added in an amount of 0.001-6.0 wt.% Based on the basic substance. The additive increases the viscosity of the electrolyte, which prevents slipping, shedding and leaching of the active mass of the electrodes (RF patent 2257647 C1, H01M10 / 26, 07.27.2005). However, this supplement does not completely prevent these harmful processes.

It should be noted that from the prior art not a single additive was found that would change the course of the chemical reaction in lead

15 acid battery in such a way as to completely eliminate the formation of lead sulfate.

Therefore, to expand the assortment of additives that provide a solution to existing problems, a simple, universal, composition of the additive and its application method was proposed that improves the characteristics of both

20 lead-acid and alkaline batteries (discharge capacity, emf, service life, environmental safety).

As a prototype for the second invention, a method for improving the electrical and operational characteristics of batteries is adopted, which involves the introduction of 0.02-0.4% of a mixture of spatially

25 hindered phenols: agidol-1 and bisalkophene, taken in the mass ratio (50-99): (50-1), moreover, for alkaline batteries, this mixture of phenols is introduced into the electrolyte or paste used to form one or both electrodes, and for acidic ones into paste (RF patent Ns 2166815 C1, H01 M10 / 12, H01 M10 / 26, 05/10/2001). The method involves the use of a universal additive that increases the service life by reducing self-discharge, preventing the formation of a dielectric layer of lead sulfate in an acid battery. The downside is that it doesn't reduces the swelling of the active mass of the positive electrode and does not increase its strength, and in an acid battery does not completely eliminate sulfation, which affects the battery life. In addition, the disadvantages of the method include the toxicity of compounds 5 of phenol and, in this regard, the problems associated with the implementation of the method and waste disposal.

Disclosure of invention

The present invention is the creation of an additive to the electrolyte and paste of the positive electrode of a chemical source of current and a method for improving the electrical and operational characteristics of lead-acid and alkaline batteries, allowing to increase the discharge capacity and service life of chemical current sources, including batteries, both new and and in operation.

The task is achieved by a group of inventions, united by 15 single inventive concept.

Indeed, to improve the electrical and operational characteristics of the batteries, a new additive was developed, which is introduced into the electrolyte of both the lead-acid and alkaline batteries during charging of the battery, as well as

20 is used in the formation of a positive electrode.

According to the first invention, the problem is solved in that the addition to the electrolyte and paste of a positive electrode of a chemical current source includes distilled water and tetrasodium or disodium salt of ethylenediamine-tetraacetic acid in the following 25 ratio of ingredients, wt%: tetrasodium or disodium salt of ethylene diamine-tetraacetic acid 0.05 -99.95; water the rest.

According to the second invention, the problem is solved by the fact that in the method of improving the electrical and operational characteristics of lead-acid and alkaline batteries, comprising treating the positive electrodes of the battery with a paste with an additive or introducing an additive into an electrolyte, an aqueous solution of ethylenediamine-disodium or disodium salt is taken as an additive tetraacetic acid, moreover, the additive is introduced either into the electrolyte, mainly in charging mode of the battery, or added to the paste during the formation of positive electrodes in an amount of 0.5 - 1, 2 wt.% in terms of salt for a lead-acid battery and 0.1 - 40.0 wt% for alkaline.

5 In the proposed method, the electrolyte and the additive for the lead-acid battery are taken in the following ratio of ingredients, wt.%: Concentrated sulfuric acid 28-38; tetrasodium or disodium salt of ethylenediamine-tetraacetic acid 0.7-0.8; distilled water the rest. S A electrolyte and an additive for an alkaline battery are taken in the following ratio of ingredients, wt.%: alkali metal hydroxide 0.5-30.0; tetrasodium or disodium salt of ethylenediamine-tetraacetic acid 0.1-4.0; distilled water the rest.

Tetrasodium or disodium salt of ethylenediamine - tetraacetic

15 acid, which is included in the additive, contains ionogenic groups, which, along with alkali and acid ions, are carriers of electric current, that is, they significantly reduce the internal resistance of the battery, while increasing the battery capacity, Ah and its EMF.

The increase in sodium ions in the electrolyte as for lead acid,

20 and for alkaline batteries, it increases the viscosity of the electrolyte, reduces its friction coefficient, which significantly reduces such harmful processes as creeping, shedding and leaching of the active mass of the positive electrode.

And the presence of ethylene diamine group in solution allows increasing

25 the adhesion of the active mass with the electrodes, which ensures the formation on the surface of the positive electrodes of the polymer, highly conductive permeable to electrolyte frame, holding the active mass, preventing its shedding.

In addition, the manufacture and use of the proposed additives zo meets environmental safety standards.

In an electrolyte for a lead-acid battery, including the aforementioned additive, reciprocal current-forming processes proceed according to the following chemical reaction: NaOOC-HoC CH ₂ COONa discharge

Pb + PbO ₂ + 2H ₂ SO ₄ + N-CH ₂ -CH ₂ -N>

NaOOC-HiC 4

CH ₂ COONa charge

discharge ^ - 0OC-H ₂ C CH ₂ COO

+ 2Na ₂ SO ₄ + Pb. N-CH ₂ -CH ₂ -N Pb + 2H ₂ O

“- charge 0OC-H ₂ C ^• CH-, COO

As can be seen from the equation, the chemical reaction of reciprocal current-forming processes occurs without the formation of lead sulfate, which completely prevents sulfation of the battery, and as a result significantly increases its life.

In addition, the salts mentioned above are non-toxic, and therefore the use of additives and the proposed method provides environmental safety.

Thus, the totality of the proposed features makes it possible to completely prevent (and not partially, as in the analogs) the sliding, shedding and washing out of the active mass of the positive electrodes of the batteries, and, in addition, to completely eliminate sulfation of the plates in a lead-acid battery.

Embodiments of the invention and industrial applicability

The preparation of an additive to the electrolyte and paste of a positive electrode of a chemical current source is carried out by mixing distilled water and tetrasodium or disodium salt of ethylenediamine-tetraacetic acid in the following ratio of ingredients, wt%: tetrasodium salt of ethylenediamine-tetraacetic acid or disodium salt of ethylene diamine-tetraacetic acid 0,0 95.5; distilled water the rest.

The following are examples of proposed formulations of additives and electrolytes with additives. Example 1. The additive to the paste of the positive electrode of a chemical current source of small capacity contains wt.%: Tetrasodium or disodium salt of ethylenediamine-tetraacetic acid 0.05; distilled water 99.95. Example 2. The additive to the electrolyte and paste of the positive electrode of a lead-acid battery contains wt.%: Tetrasodium or disodium salt of ethylenediamine-tetraacetic acid 50.0; distilled water 50.0.

Example 3. The additive to the electrolyte and paste of the positive electrode of an alkaline battery contains wt.%: Tetrasodium or disodium salt of ethylenediamine-tetraacetic acid 2.0; distilled water 98.0.

The method is as follows.

Electrolyte is poured into the battery. Then the battery is connected to the charger and the estimated amount of additive is introduced.

(0.5-1, 2 wt.% In terms of the amount of salt for a lead-acid battery and 0.1-40.0 wt.% For an alkaline battery), and then kept under tension until the battery is fully charged.

The estimated amount of additive can be introduced into the paste in the manufacture of positive electrodes of the battery. In this case, the introduction of an additive to the electrolyte is not performed.

The tables provide examples of electrolyte compositions. Table 1. The electrolyte compositions for the lead-acid battery.

Table 2. The composition of the electrolyte alkaline battery

The proposed additive to the electrolyte or paste of the positive electrode and the method can be used both in the manufacture of new batteries and to improve the performance of batteries in use.

For batteries in use, the additive is introduced into the electrolyte once for the entire life of the battery.

Prototypes of lead-acid batteries have been in operation for over 10 years (since January 1996) without any maintenance, while maintaining their energy characteristics and electrolyte composition. The shedding and subsidence of the active mass of the electrodes were not observed.

At the LIK enterprise in Cherkasy, Ukraine, two prototypes of 6CT-60 batteries made from one batch of lead plates were tested. Sample 1 was filled with sulfuric acid electrolyte and charged, sample 2 was formed using the proposed additives and way.

The test results are presented in tables 3-5. Table 3

Table 4

Starter test

Table 5

Traction tests

As can be seen from the test results, the battery formed using the claimed technical solutions, according to verified indicators, significantly exceeds the battery formed without the use of additives.

Claims

Claim

1. Additive to the electrolyte and paste of the positive electrode of a chemical current source, including distilled water and tetrasodium or disodium salt of ethylenediamine-tetraacetic

5 acids in the following ratio of ingredients, wt%:

Ethylenediamine-tetraacetic acid tetrasodium salt or ethylenediamine-tetraacetic acid disodium salt 0.05-99.95 Distilled water the rest.

2. A method of improving the electrical and operational characteristics of lead-acid and alkaline batteries, comprising treating the positive electrode of the battery with a paste with an additive or introducing an additive into an electrolyte, characterized in that an aqueous solution of tetrasodium or disodium salt of ethylenediamine-tetraacetic acid is taken as an additive, moreover, the additive 15 is introduced either into the electrolyte, mainly in the charging mode of the battery, or added to the paste during the formation of positive electrodes in an amount of 0.5 - 1, 2 wt.% in terms of salt for lead-acid battery and 0.1-40 , 0 wt% - for alkaline.

20 3. The method according to claim 2, characterized in that the electrolyte and the additive for the lead-acid battery are taken in the following ratio of ingredients, wt.%:

Concentrated Sulfuric Acid 28-38

Ethylenediamine-tetraacetic acid tetrasodium salt or ethylenediamine-tetraacetic acid 25 disodium salt 0.7-0.8

Distilled water rest.

4. The method according to claim 2, characterized in that the electrolyte and the additive for an alkaline battery are taken in the following ratio of ingredients, wt.%: Zo Alkali metal hydroxide 0.5-30.0

Ethylenediamine-tetraacetic acid tetrasodium salt or ethylenediamine-tetraacetic acid disodium salt 0.1-4.0 Distilled water the rest.