WO1997023921A1 - Electrolytes for lead storage batteries and methods of producing and using same - Google Patents

Abstract

The invention relates to the following: a) additive made from combinations of sulphuric salt solutions as lead storage battery electrolyte, containing 1.00-3.00 % zinc ions and indium (III) ions (no more than 2.50%) and/or gallium (III) ions (no more than 2.50%), and other auxiliary agents suitable for modifying the density of the additive (the effect of the additive is synergistically increasing during the charging process); the proposed additive is used for improving the charge acceptance value and other characteristic values, for conditioning the battery and for regenerating old batteries; b) methods of producing the additive described in a); c) additives for the negative plate material of the lead storage battery, namely 0.20-0.60 % zinc and no more than 0.50 % indium (III) and/or no more than 0.50 % gallium (III) ions relative to the quantity of powder lead oxide.

Description

 ELECTROLYTE FOR LEAD BATTERIES AND

METHOD FOR THE PRODUCTION AND USE THEREOF

Technical field

The invention relates to an electrolyte concentrate having a density of approximately 1.28 kg / dm and containing various water-soluble sulfuric salts. The ready-to-use concentrate can be used as an additive mixed directly with the sulfuric acid, or its main active ingredients must be incorporated into the negative mass during the manufacturing process of the plates. By means of synergism, the active ingredients of the additive have a favorable effect on the characteristic value of charge acceptance, which expresses the operational safety of the battery, and on other characteristics of the battery. In addition, when using old batteries, the lost capacity partially comes back, i.e. the battery tapers.

The main components of the additive according to the invention are zinc, indium (III) and / or gallium (III) ions. To ensure the density of 1.28 kg / dm ³ , the additive also contains magnesium and aluminum ions.

State of the art

Trans. Electrochem. Soc. 92, 229 (1947)), obwohl nicht im Interesse der obererwahnten Zwecke. Anfangs wurde das Zinksulfat in der Plattenmasse als Bindematerial, später als ein Porositätsverbesserer angewandt (US.P. 566 531; 778 894; 1 603 291).Some water-soluble sulfates have been used in batteries since the 1920s (Ritchie, E.

Trans. Electrochem. Soc. 92, 229 (1947)), although not in the interest of the above-mentioned purposes. Zinc sulfate was initially used in the plate mass as a binding material, later as a porosity improver (USP 566,531; 778,894; 1,603,291).

The water-soluble sulfates have a field of application of a different kind in the production process of "without electrolyte storable batteries" (dry or wet charge type batteries, for example US.P. 580 319; 3 988 165), where the formed negative plates as a result of rinsing with the sulfate concentrate against oxidation and against the formation of lead sulfate of macrocrystalline structure. According to the last patent mentioned above, the zinc ion was used for the above purpose as "Excellent", which categorizes indium ion as "still usable". The gallium ion was not mentioned.

An extensive application of the water-soluble sulfates can be seen in numerous "battery rejuvenators". The role of sulfates in these products is that their presence in the battery prevents the formation of the so-called "secondary" lead sulfate, which is electrochemically inactive and consequently causes the aging and deterioration of the battery (US.P. 357 642;

398 194; 512 823; 681 329; 1 291 167). The newer rejuvenating agents generally contain the following cations: alkali metal, aluminum (e.g. Ger.P. 893 812), magnesium cadmium (e.g. Fr.P. 1 308 898; JP 6 118 312; HU P. 159 337) and Gallium (HUP. 209023) ions.

Using quantitative electrochemical methods, Kabanow, BN and his team - first in the literature - investigated the effect of some of the above water-soluble sulfates on the charging and discharging processes of the lead acid battery (Yampolskaya, EG - Boromissza-Varga, E. - Martinowa, MI - Smirnowa, IA - Kabanow, BN: Zh.prikL khim. 49, (1 1) 2421, (1976); 50, 11, 2509 (1977); Boromissza-Varga, £., Magy.Kem. Lapja, 40, 54, (1985)). It was determined that there are significant differences between the parameters in the presence of different cations. It was also found that the effect of the individual cations depends on the type of expander used in the negative mass.

From later investigations (unpublished results by Boromissza-Varga, E.) it can be concluded that the soluble sulfates exert their effect on the operation of the battery in those steps of the electrode process where the reaction rate is regulated by the dissolution of the lead sulfate. Those cations are more effective which, due to various morphological causes (isomorphism, double salt formation, trace elements present as construction errors, etc.), can be built into the crystal lattice of the lead sulfate and thereby favor its instability and dissolution. The degree of activity of soluble sulfates can mainly be found in the

Show characteristic values of charge absorption. In the past decades, the characteristic value of the charge acceptance has gained great importance because it Regeneration ability of the battery and thus the safety of starting the

Motor vehicle more precisely than the value of the capacity can reflect. That means, the circumstances of the determination of the charge acceptance (partially, to 50%)

State, constant potential) correspond to the circumstances in the operation of the starter accumulator rather than the circumstances when determining the capacity (fully charged state, decreasing potential).

Presentation of the invention

As a result of the above test results and considerations, the improvement of the charge acceptance in addition to the securing of the good values of all other characteristics of the battery was chosen as the central point of the conception of the present invention. A second purpose was to reduce or completely eliminate the use of the effective but extremely poisonous cadmium ion, thereby significantly reducing the environmental impact of the additive.

In the interest of realizing the above purposes, a number of suitable, water-soluble sulfates of the general "standard test specification for starter accumulators, M.Sz. 1840. 1-69." corresponding quantitative

Subjected to series of investigations. (For the method see the above-cited publication by Boromiszsza-Varga E.). The most important details of the overall test of the cations selected on the basis of the measurement results were summarized in Table 1.

The cell used in the experiments contained a negative plate between two isolated positive plates in the sulfuric acid-containing electrolyte (D = 1.28 kg / dm ³ ). All experiments were carried out with an equivalent amount of cations, namely the total valence charges of the metal ions in the entire volume was 7X10 ^"4 F. If there were several (N) cations in the electrolyte, the individual cations had a valence charge of

It can be seen from Table 1. that from the point of view of charge acceptance, the additive-free negative plate (lead oxide, sulfuric acid, water) (1.) has a maximum value (100%) (in addition to minimum capacity). In relation to this value, the expander-containing plate has the value of 54.1% and the same with Barium sulfate the value of 53.9%. The negative effect in the loading process: this

Surcharges are partially and differently compensated for by the individual cations (4th to 9th), consequently the above percent in their presence in the electrolyte is increased to 57-85%. The simultaneous presence of the cations in the electrolyte (10.) shows a synergistic effect, so the collective has a 6.7% higher value

(77.3%), as the mean of the sum of the value of individual components (70.6%) for the same amount of valence charges in the electrolyte.

As for the other characteristics of Table 1 in the presence of the cations examined, all have normal or improved values:

- The capacity is the best besides zinc, cadmium, gallium and indium ions;

- The steepness (n) of the Peukert's deflection curve (In i - In t) is favorably reduced by 23% by zinc, cadmium, gallium, and indium ions. It means a smaller loss of capacity in discharges with higher current densities than those used in the K20 regulations;

- From the standpoint of self-discharge, the steepness of Tafel's curve (b) is reduced in the presence of zinc, cadmium, gallium, indium ions;

- The internal resistance of the cell is reduced by all of the cations in Table 1, but mainly by the aluminum ion.

On the basis of the test results, the additive combinations were designed in such a way that the more effective components should play a key role in this. The less effective cations were used to ensure the appropriate density of the concentrate and to improve the internal resistance.

A combination of a reduced cadmium content was also produced, but according to the test results this component is replaceable and dispensable.

The percentage of cations in the additive is as follows: Zn ²⁺ : 1.00 - 3.00

In ³⁺ : O, OO - 2.5O Ga ³⁺ : O, OO - 2.5O Al ³⁺ : 1.50-3.00

Mg ²⁺ : 1.00 - 3.00

Cd ²⁺ : 0.00-1.20; (g cation in 100 ml concentrate).

The additive according to the invention contained the cations as sulfates, which, however, in certain cases are to be produced from the following inorganic compounds in the interest of lowering self-costs:

Zinc, magnesium, cadmium sulfates from the corresponding oxides,

Hydroxides and carbonates;

Gallium, indium and aluminum sulfates from the corresponding hydroxides and carbonates;

Zinc sulfate by direct dissolution of the metal in sulfuric acid;

Indium and gallium sulfates by anodic oxidation of the corresponding

Metals with adaptation of specialist literary methods (Hurlen, T.: Electrochim. Acta, 9,

1439 (1964); HU P. 158 042). The latter two processes have the further advantage that their excess of acid can be used to neutralize some other basic components.

In general, the additives for batteries sold also contain a complex-forming, organic acid, although the experts strive to avoid the so-called "acetic acid effect" in the battery. On the other hand, the "Kolbe's reaction" is known in which the acetic acid is oxidized to methane plus carbon dioxide on a lead electrode; it is therefore to be assumed that the other organic acids will become inert during the first electrolysis in the battery. No complex-forming acid was used in the electrochemical investigations because experience has shown that it has no effect on these processes. If, however, a complex-forming acid turns out to be necessary in certain cases (eg due to the promotion of the dissolution), tartaric acid in a quantity of 1.00-2.00% in the concentrate is preferred. Because the measurement results from Bushrod, CJ. and Hampson, NΛ. (Brit. Corros. J. 6, 129 (1971)) prove that this compound can reduce stress in the positive plate. As a result of suitable combinations of some effective sulfates, the additive according to the invention means a step forward in comparison with the prior art

Technology because it helped to solve several problems at the same time:

- improves the load absorption (to a greater extent in comparison with the previous combinations) and thereby increases the safety of starting the motor vehicle;

- Reduces the internal resistance of the cell (heating and loss of the

Electrolytes);

- prevents the formation of the electrochemically inactive secondary lead sulfate on the surface of the plates;

- reduces the loss of capacity when using higher current densities than those used to determine K ₂ O (steepness of the Peukerts deflection curve);

- dissolves the discharge of the secondary lead sulfate in the old batteries, the recently activated substance can thereby participate in the cyclization process, as well as increasing the capacity and extending the service life;

- enables the use of the effective but extremely poisonous cadmium ion to be reduced or eliminated, thereby significantly reducing the environmental damage to the additive; - consequently, that the additive is effective at an interface:

Plate / electrolyte, it is clear that it is applicable in any case where this area is given. In addition to conventional batteries, it can also be used in "dry or wet charge type" batteries or for jelly-like electrolytes.

The invention is illustrated by the examples below with the emphasis that the protection area does not refer only to these egg examples.

In view of the effect, the cells containing the additives according to the 1st to 4th examples were compared with the additive-free cells or with the cells containing cadmium-containing additives ("Neoakuvite") produced in accordance with HU P. 209 O23 (Table 2.). Table 2. contains two characteristics:

- The positive active mass in grams (g / Ah) required to generate 1 amp hour; - that in the test of charge absorption in the tenth minute at 0 ° C and at V =

2.40 V / cell amps absorbed by 1 gram of positive mass (A / g).

The average results show that those with the invention

Combinations of cells - in relation of g / Ah by 4.00% compared to the additive-free cells, by 1.00% compared to the cells containing "neoakuvite";

- in relation to A / g compared to the additive-free cells by 44.60% and compared to the cells with "Neoakuvit" produced 1.60% better values.

Best way to carry out the invention

Example 1.

In the cell box, metallic gallium serves as the anode and 24% sulfuric acid (6490 ml) serves as the electrolyte. This is dissolved during the electrolysis

Gallium ion checked gravimetrically.

The electrolysis ends at a concentration of 1.54% of the gallium ion.

Then zinc oxide (ZnO; 174.00 g), indium hydroxide (In (OH>; 15, OO g),

Magnesium oxide (MgO; 1 16, IO g), aluminum hydroxide (Al (OH)}; 578.00 g) dissolved in the electrolyte. After cooling, the solution is made up to 8OOO ml. This

The amount, corresponding to 100 parts, is sufficient for 100 starter batteries in such a way that 13 - 13 ml of additive is poured into each individual cell of the 12 volt battery.

The general weighting of the additive is: 18 ml concentrate / kg sulfuric acid.

Table 2 shows the test results relating to the effectiveness of the additive corresponding to Example 1.

Example 2.

The following chemically pure, crystalline compounds are heated in 25 ml of water with stirring until dissolved: zinc sulfate (ZnSO ₄ .7H ₂ O; 8.10 g), indium sulfate (In ₂ (SO ₄ ) ₃ ; 4, OO g), aluminum sulfate ( al ₂ (SO _{4) 3} .18H ₂ O; 22 OO g),

Magnesium sulfate (MgSO ₄ .7H ₂ O; 6.00 g) and tartaric acid (1.50 g). To

After cooling, the solution is made up to 78.0 ml. That amount is going into a battery of measured in Example 1. Table 2. shows the test results relating to the effectiveness of the example 2

Admixture.

Example 3.

The following materials are dissolved in 50 ml of a solution containing sulfuric acid (8.00 M / 1) with stirring and with slow gassing: aluminum hydroxide (Al (OH) ₃ ; 5.15 g), cadmium oxide (CdO; 1.00 g), gallium hydroxide (Ga (OH) ₃ ; 1.70 g), magnesium oxide (MgO; l, OO g), zinc carbonate (ZnCO ₃ ; 2.52 g). After cooling, the solution is made up to 78.0 ml. This quantity is measured in a battery in accordance with the instructions written down in example 1. Table 2 shows the test results relating to the effectiveness of the additive corresponding to Example 3.

Example 4.

Zinc sulfate (ZnSO ₄ .7H ₂ O; 8.10 g), gallium sulfate (Ga ₂ (SO ₄ ) ₃ .18H ₂ O; 5.75 g), aluminum sulfate (Al ₂ (SO ₄ ) ₃ .18H ₂ O; 22 , OO g), magnesium sulfate (MgSO ₄ .7H ₂ O; 6.00 g) and tartaric acid (1.50 g) are heated in 25 ml of water with stirring until dissolved. After cooling, the solution is made up to 78.0 ml. This quantity is measured in a battery in accordance with the instructions written down in example 1. Table 2 shows the test results relating to the effectiveness of the additive corresponding to Example 4.

Example 5. Using the substances corresponding to the technological regulations of the battery industry, a negative mass is compiled with the conventional technology from the following components: powdery lead oxide (PbO;

4OO, OO g), additives (expander, BaSO ₄ , soot, etc .; 2.30 g in total) “water

(25 ml), additive according to Example 1. (78.0 ml), sulfuric acid (D = 1.38 kg / dm ³ ; 32.5 ml). This amount is sufficient for 6 negative plates. The additive according to the invention has the same effect on the characteristics in the

Mass as in the electrolyte. Table 1.

Examination of the cation effect on the negative plate

Example additional discharge charging Peukert Tafel Innen¬

No. in the (Ah) (V = 2.4V; O ° C; wider)

Mass H ₂ SO ₄ O, 5OA 4.42A in 10 min.)

(A) (ή) (b) Ohm x lO ²

1. 2.10 0.63 0.665 (100%) l, OO O, 14 5.93

2nd exp. 2.14 1.00 0.360 (54.1%) 1.87 0.26 6.57 3rd exp. + BaSO ₄ 2.15 1.01 0.359 (53.9%) 1.88 0 , 26 6.57

4. AI 2.18 1.02 0.380 (57.1%) 1.77 0.23 5.01 5. Mg 2.22 L, O4 0.430 (64.6%) 1.82 0.24 5.22 6. Zn 2.20 1.27 0.420 (63.1%) 1.44 O, 21 5.60 7. Cd 2.10 1.22 0.488 (73.3%) 1.45 O, 21 5.62 8. Ga 2.38 1.30 0.534 (80.3%) 1.48 0.22 5.62 9. In 2.42 1.28 0.567 (85.2%) 1.44 0.19 5.59 10. All 2.44 1.51 0.514 (77.3%) 1.45 0.21 5.58

Table 2. Examination of admixture combinations on the positive plate

Addition: - Neoakuvite examples

1. 2. 3. 4.

Positives

Mass (g): 78.95 78.99 79.02 78.62 79.54 79.10

K2O (Ah): 10.48 10.86 11.10 10.93 10.98 10.91 g / Ah: 7.53 7.27 7.12 7.19 7.28 7.25

Charge pick-up in 10 min.

(A): 0.75 1.08 1.11 1.08 1.10 1.07

A / g.lO ³ 9.50 13.70 14.00 13.70 13.80 13.70

Claims

claims 1. Regenerating and improving the operational safety additive for starter batteries, characterized in that it contains 1.00 - 3.00% zinc ion and its effect in the charging process, increasing at most 2.50% indium (III) ion and / or at most 2.50 % Gallium (III) -ion and other auxiliary substances necessary for adjusting the density of the additive. 2. A process for the preparation of the additive according to claim 1, characterized in that one or more components of the additive is dissolved as metal in an amount of sulfuric acid equivalent to other or to all components of the additive, directly or by anodic oxidation, and then the excess acid is added neutralizing the other components added in the form of bases or carbonates. 3. electrolyte for conditioning the lead battery using the additive according to claim 1, characterized in that the additive in During the manufacturing process of the battery in the forming electrolyte is mixed in such a way that there is a concentration of the zinc ion of O, O2 - 0.10%, that of the indium ion of at most 0.06% and / or of the gallium ion of at most 0.06 % should train. 4. Electrolyte for the lead battery by using the additive corresponding to claim 1, characterized in that it contains, in addition to sulfuric acid and auxiliaries, O, O2 - 0.10% zinc ion and at most 0.06% indium ion and / or at most O, O6% gallium ion. 5. additives for plate mass of a lead battery, characterized in that in the production of the conventional negative plate mass, the following amounts of ions: O, 2O - 0.60% zinc in the form of either sulfate, oxide, hydroxide, or carbonate, and at most O, 5O % Indium and / or at most 0.50% gallium, both in the form of either sulfate, hydroxide or carbonate with respect to the amount of powdered lead oxide.