CS262274B1 - Method of regeneration of secondary cells from accumulator batteries - Google Patents

Abstract

To the battery electrolyte at least one of the compounds is added, including borate trihydrate sodium, urea peroxohydrate, peroxide sodium, potassium peroxide, persulphate sodium, potassium persulfate, ammonium persulfate and sodium carbonate perhydrate in quantities that after conversion to peroxide % hydrogen corresponds to 0.1 to 40 wt. peroxide of hydrogen, based on the electrolyte weight.

Description

The present invention relates to a method for the regeneration of secondary cells worn, due to the low capacity, of non-compliant accumulator batteries of the conventional type, both with an alkaline electrolyte and with an acid electrolyte.

At present, the life of the secondary cells is prolonged during their manufacture, in particular by avoiding the formation of passivation coatings, which in operation reduce the active surface of the electrodes. Many different reagents are used for this purpose, which are added either to electrolytes or as anti-agglomeration agents to the electrode material. These methods have a limited efficiency and only act as preventive by retarding wear.

There are two methods used for cells already degraded by chemical processes during operation.

On the one hand, it is simply rinsing the cells and removing some soluble deposits and sludge with a stream of water and replacing the degraded electrolyte with a new one. This method has only very limited efficiency; for starter cells, the charging capacity can be increased by a maximum of 30% and the cells are very old or not usable for internal short-circuiting. A second method of regeneration involves the use of a commercially available desulfurizer to remove passivation layers in lead acid battery cells. This method has not found widespread application since the preparation also damages the lead plates in the cells.

It is further known to use hydrogen peroxide to regenerate both types of secondary cells, both alkaline and acidic. A solution of hydrogen peroxide at a concentration of 0.1 to 40%, preferably 0.5 to 3%, is used.

Handling an aqueous solution of concentrated hydrogen peroxide is subject to a number of precautions that may be difficult to achieve. Also, the security requirements for hydrogen peroxide storage can be costly.

These drawbacks are overcome by the method of regenerating secondary cells of accumulator batteries by the regeneration solution while replacing the electrolyte and rinsing the battery according to the invention. It consists in adding to the battery electrolyte at least one of sodium borate trihydrate, urea peroxide, sodium peroxide, potassium peroxide, sodium persulfate, potassium persulfate, ammonium persulfate and sodium carbonate peroxohydrate in amounts which, after conversion, % to hydrogen peroxide corresponds to 0.1 to 40 wt. hydrogen peroxide, based on the electrolyte weight.

The main advantage of the process according to the invention lies in the use of such compounds for the preparation of a regeneration solution which can be stored and, if appropriate, directly metered into the electrolyte in solid form.

Alkaline electrolyte accumulators can be directly dosed with alkali metal peroxides such as potassium peroxide and / or hydrogen peroxide addition compounds and alkali metal salts such as sodium carbonate peroxohydrate of Formula 2 200-200. . The dosing must be carried out in small quantities as the gaseous components are released.

The process according to the invention is described in more detail in several exemplary embodiments.

Example 1

Lead-acid battery with 6 cells and the original capacity of 37 Ah was discarded because its capacity dropped to 26% after the charging test. The battery was partially recharged at 3.7 amps for 6 hours. 300 ml of electrolyte was poured from the accumulator and replaced by a regeneration solution formed by dissolving 100 g of sodium persulfate in 300 ml of distilled water. The regeneration process took 45 minutes. The solution was then discarded and replaced with a conventional electrolyte which, after pouring, had a density of 1.28 kg / dm ³ . The capacity test showed an increase in capacity to 37%. After regeneration twice with a regeneration solution prepared by dissolving 80 g of sodium persulfate and 49 g of sulfuric acid, a capacity of 91 g

Example 2

Lead-acid battery with 6 cells and the original capacity of 37 Ah was discarded because its capacity fell to 28%. 105 g of a solid double carbonate compound consisting of sodium carbonate and hydrogen peroxide, 2 Na ₂ CO ₃ .3 H ₂ O ₂ , were gradually added to the accumulator, with strong gas evolution. The solution was left for 45 minutes. The solution was then discarded and the battery was purged 6 times with distilled water for 6 hours each. The battery was then filled with a new electrolyte which, after pouring, had a density of 1.28 kg / dm. A capacity test was then performed which showed an increase in capacity to 87%.

Example 3

Lead-acid battery with 6 cells and the original capacity of 37 Ah was discarded because its capacity fell to 27%. 100 g of solid double hydrated sodium borate compound and hydrogen peroxide NaBO ₂ .H ₂ O ₂ .3 H ₂ O were gradually added to the accumulator. The battery was then filled with a new electrolyte which, after pouring, had a density of 1.28 kg / dm. After 24 hours of standing, a capacity test was performed which showed an increase in capacity to 62%.

Example 1

The 5-cell Ni / Cd alkaline battery with an original 90 Ah capacity showed only 38% capacity after charging to 150% capacity (9 A) and 9 A discharge. It was therefore regenerated by adding 220 g of potassium peroxide K ₂ O ₂ , which was gradually added directly to the battery.

After the regeneration lasting 25 minutes, the electrolyte and sludge were discarded and, after removing the impurities, the electrolyte concentration was adjusted to 1.20 kg / dm after charging with distilled water. The electrolyte was returned to the battery and the 9 A capacitance test showed 88% capacity.

Example 5

Alkaline accumulator Ni / Cd with 5 cells with original capacity 90 A.h showed after charging to 150% capacity and after discharge with 9 A current only 27% capacity. It was therefore regenerated by adding 300 g of urea peroxohydrate, which was dosed into the filtered electrolyte in a beaker outside the battery. After a vigorous reaction, while the electrolyte was continuously cooled to 20 ° C, the regeneration solution was poured into an accumulator where regeneration was carried out for 35 minutes. The electrolyte was then discarded, filtered from the sludge and adjusted to a density of 1.20 kg / dm, measured after charging. The 9 A capacitance test showed 84% of the capacity.

Example 6

The 5-cell Ni-Cd alkaline battery with an original capacity of 90 Ah showed only 24% of capacity when charged to 150% capacity and discharged with 9 A. It was therefore regenerated by the addition of 400 g of a double compound of sodium carbonate and hydrogen peroxide 2 Na 2 O 2 .SH ₂ O ₂ , which was dosed into the original electrolyte after filtration from the sludge. The regeneration solution was left in the battery for 35 minutes, then poured out of the battery. The battery was flushed 6 times with distilled water for 20 minutes each, and then was charged with a new electrolyte to a density of 1.20 kg / dm, measured after charging. After 24 hours, a capacity test was performed that showed 77% of the original capacity.

Example 7

The 5-cell alkaline Ni / Cd battery with an original 90 Ah capacity showed only 26% of capacity when charged to 150 ·% capacity and discharged with 9 A. It was therefore regenerated by the addition of 120 g of double hydrated sodium borate compound and hydrogen peroxide NaBO ₂ · H ₂ O ₂ -3 H 10, dissolved in the original electrolyte after filtration from the sludge. The regeneration solution was left in the battery for 35 minutes and then discarded. The battery was flushed 6 times with distilled water for 20 minutes each, and then was charged with a new electrolyte to a density of 1.24 kg / dm as measured after charging. A capacity test was performed after 24 hours, showing 82% of the original capacity.

Example 8

Alkaline accumulator with 5 cells with original capacity 90 A.h showed after charging to 150% capacity and after discharge with 9 A current only 22% capacity. It was therefore regenerated by the addition of a mixture containing 150 g of a double compound consisting of sodium carbonate and hydrogen peroxide,

Na ₂ CO 3 H ₂ O ₂ and 60 g of a double hydrated compound consisting of sodium borate and hydrogen peroxide, NaBO ₂ .H ₂ O ₂ .3 H ₂ O. These substances were added to the original electrolyte. The regeneration solution was left in the battery for 40 minutes and then discarded. The battery was flushed with 2x distilled water for 20 minutes each, and then was charged with a new electrolyte to a density of 1.20 kg / dm as measured after charging. A capacity test was performed after 24 hours, showing 84% of the original capacity.

Claims (1)

object of the invention A method of regenerating secondary cells of a battery by treatment with a regeneration solution by replacing the electrolyte and rinsing the battery, comprising adding to the battery electrolyte at least one of borate-sodium trihydrate, urea peroxide, sodium peroxide, potassium peroxide, sodium persulfate, potassium persulfate, ammonium persulfate and sodium carbonate peroxohydrate in an amount corresponding to 0.1 to 40% by weight of hydrogen peroxide when converted to hydrogen peroxide. hydrogen peroxide, based on the electrolyte weight.