DE1812518A1 - Accumulator water loss reduction - Google Patents

Abstract

The hydrogen-oxygen gas mixture resulting from accumulator overloading is catalytically combined to form water which is returned to the accumulator. The catalyst may contain 0.1 to 1% Pt-gp. metal (e.g. Pd) in an aluminium silicate or oxide base, made hydrophobic by treatment with dimethyldichlorosilane.

Description

Process for reducing water losses in accumulators.

The invention relates to a method for reducing the overload and discharge through formation of hydrogen and oxygen occurring water losses in accumulators.

In the case of the usual lead-acid batteries, the disadvantage is that Overcharge and discharge some of the water of the dilute sulfuric acid under Formation of hydrogen and oxygen is decomposed electrolytically. One is therefore forced to replace the lost water at relatively short intervals. This constant monitoring of the water level of such lead-acid batteries is in in most cases cumbersome and restricts-the application possibilities, in particular in hard-to-reach places.

The invention was based on the task at hand, a method for Reduction in overcharging and discharging due to the formation of hydrogen and Oxygen to indicate water losses occurring in Rkuiulatoren, by means of which there is no need to replace the lost water.

The characteristic end of the invention is to be seen in the fact that the resulting The hydrogen-oxygen mixture is catalytically burned and demineralized in the form of water Accumulator is fed back.

To carry out the catalytic combustion are preferably Supported catalysts are used, which are based on a mineral-based carrier consist of aluminum silicate or oxide, which act as a catalyzing substance Metal the Platinum group, in particular palladium, is applied, Such catalysts are already effective at room temperature and are essential Part of the resulting hydrogen-oxygen mixture is converted back into water.

The effectiveness of such catalysts is, however, to a certain extent Time reduced by absorption of the water formed into the capillary spaces of the carrier, whereby they lose their dimensional stability and, moreover, their catalytic function can.

The effectiveness and dimensional stability of these catalysts can be now, surprisingly, improve significantly by treating this with Organohalosilanes on their surface or the surface of the carrier material hydrophobic properties are imparted. Your wetting behavior towards water is completely changed here. That from the through electrolysis to hydrogen and Oxygen and catalytic combustion of the gas mixture is formed water no longer wet but condense on the outermost surface of the catalyst to larger droplets, the interiors of the catalysts or their supports unwetted and dimensional stability and catalytic effectiveness are fully retained.

For the hydrophobization of such catalysts or their carrier materials these are for example with organohalosilanes, especially dimethyldichlorosilane, Treated in the vapor phase or the carrier masses are treated before they are shaped. e.g. to pellets, already mixed with hydrophobic material or the total amount of Carrier material replaced by finely divided carrier material that has already been hydrophobized.

Hydrophobized silicas can be used as such hydrophobized substances or aluminum oxide or silicates are used9 which both on, synthetically, as well as consist of natural substances.

In practical tests it has been found that when using this Iiatalyaatorcn the water loss from accumulators can be reduced by about 9/10 can be increased and thus the maintenance times <1cs batteries ontsprochond.

A preferred form of attachment of these accumulators is in enclosed schematic drawing; nn recognizes an accumulator 1 with electrodes 7 and 8 and an electrolyte clay 12, above which, the cathode compartment 11 of the accumulator 1 finally upwards, s @@ ch first a filter, e.g. a Glass fleece 2, and above this glass fleece 2 at a certain distance above a perforated Plastic plate 3 catalysts 4, e.g. in the form of pellets, are arranged. That The hydrogen-oxygen mixture emerging from the cathode space 11 initially flows through it the glass fleece 2 untl is then burned on the catalyst elements 4 to form water. The water flowing back is filtered in the glass fleece 2, so that for example small amounts of the catalyst substance, which with the relatively long periods of use can exit from the catalyst bed 4, but not get into the cathode compartment may be caught.

also recognizes a potting plate 5 which closes the accumulator and which feeds the electrodes, which have been stripped of the tanned catalyst bed 4 and 81 are broken. The filler neck is closed by a plug 6. For the sake of clarity, the conductive connections between the individual plus electrodes and minus electrodes are not shown.

In the following, the mode of operation is illustrated using comparative examples explain the process according to the invention in more detail: The tests were carried out on commercial Batteries (2 v, 66 A / H).

filled with a 6 igen silicic acid battery acid gel. The effectiveness of various palladium catalysts was tested for: a. Continuous overloading with different amperages, in the case of shock overloading with regular Alternation of overload and rest periods and c, exposure to moisture the catalyst.

The palladium catalysts used differ according to the concentration of palladium and / hydrophilic resp.

hydrophobic character and were filled in an amount of 40 g.

To a) particularly applies to batteries in motor vehicles, depending on the alternator and setting the controller to different levels of overcharge current. This amperage is in the order of magnitude of a few amperes as it increases Overcharge current increases the amount of non-catalyzed oxyhydrogen and thus the water loss.

; 3ci the experiments showed that the water loss is dout lich decreased, the hydrophobized catalysts being more effective than the unchanged ones hydrophilic catalysts. In addition, with the hydrophobic types after a The shorter the duration of the catalysis increases the effectiveness.

If you consider the water loss of a conventional lead battery per A / h overcharging starts at 100%, the loss with the addition of a catalyst is of the order of magnitude from 1-50. the The best results were obtained with a 1% (palladium) water repellent catalyst achieved.

In Table 1 are the results using various Catalysts shown in comparison to a blind test.

Regarding b) After the start of the shock overload, every catalyst needs a catalytic converter a certain time / until the catalysis starts. This manifests itself in a higher one Water loss compared to permanent overload with the same current passage. By application the hydrophobic catalysts could reduce the water loss Akkv to approx. 10% will.

In Table II the results are given using various Catalysts shown in comparison with a blank test.

Re c) The effectiveness of the catalysts is only maintained as long as when the oxyhydrogen gas has unimpeded access to the palladium particles. Catalyzed However, water and moisture soon cover the catalysts, which only start again after the water has dripped off. With hydrophilic catalysts there is therefore a risk that this will after a certain period of time be caused by the drawing in of water in the capillary spaces lose effectiveness and become passive and only after drying able to catalyze again.

Hydrophobic catalysts, on the other hand, do not wet even when immersed in water and catalyze the oxyhydrogen gas again immediately as soon as the water has drained off (see Table III), Table I Overload Overload time loss of charge and weight of the battery per day amperage catalyst with: without 0.1% Pd 1% Pd 0.1% Pd 1% Pd catalysis (hydrophobic) (hydrophobic) gate (Days) (A) (g) (g) (g) (g) (g) 2 2.6 4.9 2.9 2.3 2.3 18.4 4 2.4 1.7 1.6 1.6 0.4 16.7 2 2.2 0.5 # 0 0.4 # 0 15.3 30 1.0 0.5 0.6 0.1 0.1 7.0 3 3.0 4.5 1.7 3.4 0.8 20.9 7 3.3 4.9 4.8 1.0 0.2 23.0 1 5.0 18.7 10.5 12.1 5.1 34.8 Table II Water loss with shock overload per 24 hours: 8 hours alternating 1 hour at 3 A overload and 1 hour rest; then 16 hours of rest. Readings Overload time (days) 8 Overcharge current (A) 3 Weight loss of the battery pro Day continuous overload Catalyst with 0.1% Pd (g) 4.9 1% Pd (g) 2.4 0.1% Pd (g) 3.0 (hydrophobic.) 1% Pd (g) 1.5 (hydrophobic.) Weight anticipation without catalyst (g) 20.9 .l.tI t lt 'III Effectiveness of the catalysts in the event of moisture exposure 10 g of catalyst were placed in a glass tube and an amount of oxyhydrogen gas of 172 ml / h (0.3 A) was passed through the glass tube. Remarks Catalyst with 1% Pd after 2 hours 0.5 ml non- katalysiortos oxyhydrogen (practically complete implementation) Catalyst with 1% Pd result as with hydrophilom (hydrophobized) catalyst Both catalysts were then covered with a layer of water; the water not absorbed was drained off again.

When the same amount of gas was passed through, the following picture emerged: Catalyst with 1% Pd after 1 hour 136 ml non-catalytic lysed oxyhydrogen Catalyst with 1% Pd as soon as the first 1 - 2 catalysts (hydrophobized) sator beads when draining the Water out of the liquid- protrude, catalysis starts. Pre@ table complete implementation.

Claims (6)

P A T E N T A N 5 P R Ü C H E 1.) Procedure to reduce the overload and discharge through Formation of hydrogen and oxygen occurring water losses in accumulators, characterized in that the resulting hydrogen-oxygen mixture is catalytic burned in water and this is fed back to the accumulator. 2.) The method according to claim 1, characterized in that for catalysis a hydrophobized KatalyvaDr is used. will. 3.) Method according to claim 1 and 2, characterized in that a Catalyst with platinum group metals is used. 4.) The method according to claim 1 to 3, characterized in that a Palladium catalyst is used. 5.) Process according to claims 1 to 4, characterized in that that a catalyst is used with 0.1 to 1.0% of the catalytically active metal will. 6.) Process according to claims 1 to 5 thereby gekennzeicinet, that the catalyst through a filter material from the electrode compartment of the accumulator used separately. Blank page