DE2612712A1 - GALVANIC FILLING ELEMENT - Google Patents

Description

PATENTATTORNEYS P AT E N TA Ν W A LT E conseils en brevets

ϊ. Η. TISCHER dipl-ing. W. KERN

rA.-ÄKWAL + E M. TISCHER - W. KERN · D β MOMCI (ERi · TAL 71 · '· ■:? - * ".''. ·. l · ---

D 8 MUNICH 2

W.-CERMftNY

, Lf. VAL 71

TELEPHONE (089) 22 12 98

TELEGRAM ADDRESS / CABLE ADDRESS

CORE PATENT MUNICH

Frefoh-6203 oa ™: ^M - March 25, 1976

YOUR MARK i OUR ZElCJi ^ N:,. _ΛΛ ^ DATE- YOUR REF.i OUR REF .:

SUBJECT REF.I

Company C. Conradty Professor

P.O. Box 480 Dr.-Ing. Wolfgang Pietrulla

8500 Nuremberg Kastanienallee 15

1000 Berlin I9

Galvanic filling element

The invention relates to a galvanic filling element with a liquid cathodic reactant.

There are galvanic filling elements known, which from the system silver chloride as a cathodic reactant against consist of a magnesium anode in seawater (Elektrotechnische Zeitschrift 14, 587; 1962). Such silver chloride filler elements have particularly proven themselves as power sources for lightbulbs, for example together with the

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Füllelemert serve as distress lights or in life jackets can be used as signal signals.

Another well-known S7 / stew uses Kunf? R (I) -cl'ilorid as cathodic reactant, also in connection with a ^ arrnesiuiianodp. Furthermore, filling elements are also iiit Zinc anodes known

A characteristic of this filling element is that the electrolyte only enters the galvanic cell during commissioning. In the case of distress signals, the electrolyte consists of army water. After entering the cell, the electrical energy runs delivering reaction "up to. Consumption of the cathodic Heactants off. In the dissolution of the ragnesiuns will not be only electrons are released, but hydrogen is also developed.

In the case of silver chloride FaCTesiun-Fv ' ¹ 1-sl hurry, the working voltage can be 1.5 - 1.55 volts. Since the electrolyte is not besieged in the system, the energy content is relatively high and can reach values of 40 Wh / kg, while energy densities of 70 Wh / 1 are possible.

While magnesium both from the point of view of availability as a raw material as well as an extremely inexpensive anode material with regard to its environmental compatibility is to be considered, and Feerwasser is also problem-free as an electrolyte, are a wide use of silver chloride as a chloride of a noble metal, also for larger cells and batteries, the critical raw material situation and, therefore, the relatively high equipment costs. If-

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same. Silver chloride elements for special items Use accidents also, in large, very powerful units are used, therefore, other cathodic ones were also used .Reactants ϊώ not included in the considerations.

Oxygen in the air was the obvious choice, so that galvanic filling elements were developed from a "cor-like carbon electrode and a zinc anode, in which ammonium chloride forms the electrolyte after the addition of tap water _T O5 _-? 1 2 volt high Ener ⁰ · stop 260 to 300 Wh / Vg and a high energy density of 230 - 2po Wh / 1 (without "Ber ^ cksichtigunp · V / ater encore), but can only relatively deliver low currents.

Recently, the company has developed a magnesium-air cell. use as Electrolyte, for example 3 "to 10% T-sodium chloride solution, being of Heervrasser, "^ inre ^ surface water or tap water is assumed. These elements are filler ^ ducks, because they also only - as is characteristic of filling elements - are activated by adding water during commissioning. Magnesium alloys are used as anode metals can be selected according to the required current load. The atmospheric oxygen serving as the cathodic reactant becomes implemented on specially developed catalyst electrodes, for example made of silver or nickel meshes with platinum or Silver catalysts "are made. These catalyst electrodes are relatively expensive, but have a long service life. The cathodic seactant is available as atmospheric oxygen available in unlimited quantities.

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Sodium chloride solutions or similar salt solutions are vroblerratic electrolytes, apart from the undesirable metal corrosion.

S so-owned Ma ^ nesium-air cell kö ^ -nen work ss ^ ^ at -uncen of 1.3 volts at a En ^ rc-ieinhalt vo ^ ICO bio / ki 120 Wh? deliver at a relatively low energy density. They are suitably adjusted for repeated use by replenishing the anode and the electrolyte. Inefficient batteries have already been raised from five Haprnesiu ^ air cells. Such cells or batteries are to be regarded as very advantageous under the aforementioned Gesichtsnunkten securing raw materials U "^ the Urnweltfreur.dlichkeit. The use eif.fecher Salzlösimnren as the electrolyte is not dangerous even when dealing directly with the Ze ¹ I s or batteries. This advantage silt compared to well-known, powerful electrochemical odorants who use strongly acidic or strongly alkaline electrolytes, and of course in the other systems discussed so far, aqueous salt solutions are used as electrolytes. A major disadvantage of these magnesium-air cells, however, is dpirin see that the catalyst electrodes for the conversion of atmospheric oxygen are complicated and expensive, since they require three-phase metal catalysts and require special manufacturing techniques up to 1.7 volts relatively low.

To avoid these disadvantages, peroxodisulphates, also called persulphates, were first investigated for their usability as cathodic seactants. D-Vbei vrar assume that for the transition SpOr. + 2e> 2 S0 _{ZL on}

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Redox potential of +2.01 volts geezer- the MorTal hydrogen electrode, eaten in alkaline solution,? Rs: R? Ce> e ^ becomes. Despite this very * high positive. Redox potential uni to the high oxygen content there are the usual persulfates verhältnisnäßig harnlose Fabrics oersulfnt Above all Annoniu ^ is produced in considerable figs and used as an oxidant in the art häufiρ. Kslv;. ~ Tj ° rHulfat u ^ d ifatrium-oersulfat are used. Persulfates are already for that too. Use ir electrochemical stro ^ .cuoll er. became known (Philips Technische Rundschau, 2p- 2C1 C ^ 967)) Here it was proposed to use a mixture of ca 1 rurmersulfat, coal powder and breading fibers RIs cathodic I ^ eteri.?! to be used, x-rinsing with sodium chloride e; impregnated breading forms the electrolyte after moistening, in the case of KasrnesiuTi or zinc as anoierrr.etall. This system resembles a dry one. ent. The Kaliumnersulfat and the sodium chloride-containing paper chi CHT can de designed as films and r? t ± a Ableitfolie to form a sandwich pack zupaminenge ^ be aut.

This known system differs from the sensing elements of the type mentioned above in that it has the cathodic reactants not in dissolved ΙΌγτ. contains and thus also not the necessity of easy emptying and K "ach.fi" llens offers. Furthermore, its performance is relative small, but its structure, especially in the case of larger units, rather complicated.

After all, it has already become known, with high-energy, water soluble salts, e.g. B. Potash roerinanganate, to work as a cathodic reactantep, whereby, however, itself the difficulty in keeping the solution away from the anode, a requirement that can only be met through the use of diaphragms, which, however, is the inner one

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Cell resistance increased considerably. According to a ^ n another "prior proposal (US-FS 2656 85Ί) are Katicnenaustauscher between the Permangaratlösung u ^ d of the zinc anode arranged vcv de" to make use of dissolved cathodic reactants reddish ( "-Elektrochemische current it ζ eucrun ^", Verlag Chemie, 1969, pp. 56/57 ^.

Therefore, the giving up of the invention is to provide a filling galvanisch.es ei ent ent d ^ r zn unknown extent, does not have the disadvantages indicated, sorderr expensive at high eir.er RuhesOannurifi with a cheaper Eathode ^^ r-TERIAL eyelets catalysts A water-soluble cathodic reactant can work on it. JJas 5Ί ""'11-element should also offer the possibility of easily removing the water-soluble cathodic reactants from the element and replenishing them with a fresh reactant, with much higher performance achievable through a relatively simple structure of larger cells meant to be.

This object is achieved in that the Cathodic reactant is an aqueous solution of a peroxodisulfate (persulfate) and is attached to a reaction and discharge cathode made of highly porous carbon material and at the same time forms the electrolyte of the filling element, its Anode made from a base. Made of metal.

The galvanic filling element according to the invention, in which the cathodic implementation: is transferred to the AbIeitelektrode in terms ¹ = Umxireltfreundlichkeit and availability of raw materials needed met, operating and production costs sowi the requirements. Lie use

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of highly porous carbon material specific compression for the reaction and discharge cathode has proven, according to an advantageous embodiment of the invention, in particular in connection with Zormköroern made of carbon for current dissipation, the formation of the cathode ar itself is arbitrary, i.e. cathodes in the form of plates, Pipes, cylinders or the like are used 'k.ör.vev .. The size distribution of the entire cathodic layer and its thickness are ¹ "" ³ ! important parameters. Very good results are obtained with a highly horny, flexible, mat-like material.

Expediently known per se can be used as anode Use magnesium alloys or iron alloys, whereby it has proven advantageous to dimension the anodes in such a way that that avenge the consumption of the dissolved reactants and after its removal, fresh reactant solution is repeated can be filled into the element, whereby. sicJi._di_e .. Beirut service time, even with intermittent operation can be extended.

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According to a further development of the inventive proposal, peroxodisulfate (persulfate) has in particular proven to be sodium peroxodisulfate or Lithiraperoxodisulfat proven, with for Dissolution of the sodium peroxodisulfate or Lithiurv deroxodisulfate Deionized water can be used, for sodium persulfate also surface water, tap water or sea water. Ammonium peroxodisulfate is because of the possibility less suitable for the development of ammonia in the alkaline range; Potassium peroxodisulfate performs because of its poor solubility to lower energy yield ^.

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"The filling el em ent can be expediently with a device for the continuous supply of the 3-part solution provided, if discontinuous operation is undesirable is, in which case the used solution is also continuous can be removed from the filling element.

Several such galvanic filling elements can be found in Combine the known method by series and parallel connection to form batteries.

The invention is described below with reference to the in the drawing illustrated Ausführungsbeisrdels explained in more detail. In the Drawing shows:

Fig. 1 is a longitudinal sectional view of an empty filling element in the form of a box-shaped cell, consisting of Lid and base.

Fig. ?. a cross-sectional view of the lower part of FIG. 1 along the line ? - ?. in Fig. 1,

3 shows a cross-sectional view of the filling element from FIG. 1, however, with the anode, cathode and carbon conductor inserted,

Fig. 4- is a plan view of the lid of the box-shaped Cell of Fig. 1, ·

Fig. 5 is a longitudinally sectioned side view of the opened Cell of Fig. 1 with a view of the anode and

6 shows a longitudinally sectioned side view of the opened The cell of FIG. 1 with a view of the cathode and carbon diverter.

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A. An essential feature of the new galvanic filling element is that the aqueous persulfate solution, which serves as a liquid cathodic peak, forms the electrolyte solution at the same time. It is generally advantageous to prepare a persulfate solution with pure, preferably fully deionized, water and pour it into the cell. "Ds a high concentration of the persulfate is desired in the aqueous solution, is used Fa.triur.persulfat, which has the highest water solubility of the commercially available persulfates. Since lithium sulfate in he still strengthening ° rem dimensions wssserlös" ¹ · I is is also di ^ s ^ R Fersulf at Wrw ^ ndune: find. Depending on the TT ^ e d ^ s outside ^ wid ^ rstar.d ^ s, higher or lower work nsn ^ s result. Ss has shown that? Usable filling element ρ ^ can be built up with only a slightly decreasing working pressure of 2 years up to the consumption of the persulfate, if the external resistance to the internal resistance is in a suitable ratio.

The effect of persulfates in aqueous solution also n ° i use of fully deionized "! water as cathodic iioactant in a functional filling element, no other Containing electrolytes can be considered several folse Explain reaction steps. While z. B. dry IT ^ triutrpersulphate can be kept undecomposed, it disintegrates into water-freak Solution with evolution of oxygen to hydrogen sulfate. the The rate of decay is temperature dependent, so d-τΒ z. B. Persulfate pan can be destroyed by cooking. at If euro erat υ r tree, the disintegration is so slow that the functionality of the filling element is not impaired.

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He =. is a ^ geno ^ me ^ that the incipient disintegration fi to start ^reaction: r the dissolution of a non-noble ¹ "anode leads, since HSC + ions are supplied speaks 7ür this A ^ nnlyne that the ρττ value too." i EXAMPLE 1 M sodium persulfate solution in deionized water is about 4 ". The corrosion of the anode continues under the evolution of hydrogen. This is more violent in a per sulfate solution than i ^ a r ^ atrium sulfate solution As a result of their high positive 3edox potential, the persulfate anions have a strong tendency to go into bisulfate or sulfite anions, for which the pores serve as the reaction space. "Ste ¹ ^ serves as the cathode. The rotated electrons are quickly supplied when there are enough base metal as a node. Magnesium is particularly good in alloys, as they are also used for cathodic protection (see 3.) transition from magnesium to tasnesium cations, the evolution of hydrogen is unavoidable for electrical reasons. As is well known, such anodes are called "Iisch anodes". If the cells are not too large, the hydrogen can escape safely Its Umvar.dlunß: is in a known way by catalytic "combustion or by electrochemical oxidation, z. B. with an auxiliary electrode, I inögl.

As a result of the hydrogen evolution, magnesium hydroxide is formed, that depends on the selection of the magnesium alloy and the Strorabelastur.g deposited on the anode or ^ r

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Deposition on the bottom of the cell decreases. The hydroxides other alloy components such as zinc and I'-angan also deposited. Together with metallic particles ■ of the anode material, these hydroxides form a 3ode ~ sludge, which is removed with the used electrolyte. ρ value of the resulting solution in the cell is approaching. gradually 8 during their operation, with the evolution of hydrogen becomes less. In parallel to the effect of the anode when a current is supplied by such an element, a warning is generated. The temperature rise depends on the current load and can reach values up to about 50 ° G.

Should the hydrogen development in the filling eggs be reduced less base anode metals can be used will. As from the aforementioned economic and raw material considerations only metals and compounds should be used, which are available in very large quantities is excluded Nagnesium considered before sis en alone. Try advice Zinc have shown that this metal is generally concentrated Persulphate solutions are attacked too vigorously, while aluminum is normally too low as a result Activity proves less suitable.

Galvanic filling elements with an anode of ¹¹ ordinary steel ST 37 are quite suitable for the stated purpose, but in this case a lower resting tension of 1.0 must be expected to be - 1.1 volts to be accepted. When loaded with an external resistor which is designed for longer, continuous operation of the filling element, the result is a working value of 0.8 volts with a very favorable discharge characteristic. ΒρΛ insert, a larger anode made of sheet steel can replace the cell several times

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The trusted natural sodium sulphate solution can be regenerated and then shows the same performance. This emptying of the spent seactants and the 'falling down of the cell work through suitable facilities on an ongoing basis, with the possibility of kr.nn, also the anodes according to their: a consumption continuously to replace. In this way, the "operating time" becomes more such galvanic filling event considerably extended.

The best results are obtained with filling elements, the anor of which consist of napoiesium alloys of the gnawed '" ¹ ""type. For the concentration of sodium carbonate sulfate in water, 1m solutions are preferred, although higher concentrations are also preferred , optionally in the presence of Bodenkörr 's are possible. Although higher concentrations give higher performance, but then there is a risk, especially at smaller electrode gap ¹¹¹ that form crystalline precipitates. on the other hand, lower concentrations may be used.

As can be seen from the drawing figures 1 to 3, the filling elements can be in the form of flat, box-shaped cells 1 can be built, but round cells are also possible here are not shown. As a housing z. B. a plastic vessel 3 made of, for example, polyethylene with the dimensions 16 χ 14 χ 4 cm, which is secured by an attached lid 2 is closable, which, as can be seen from Fig. 4-, recesses 8 in its top for two discharge rails 7 made of carbon for the cathode 6 contains. These discharge rails are shown in section in Fig. 3 and are with the surface the cathode 6 in a conductive connection. The cover 2 contains two more AussDarimge ^ 9 for two tongues 10 of the

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Kas-nesiumanoöe 5? which, as can be seen from Fig. 5, via the Plastic vessel 3 protrude and extend through the recesses in the lid. Furthermore, the cover is 2 provided with an opening H for filling the element, the i * n Operating state remains open and the escape of the emerging Hydrogen allows as well as to remove the used solutions can serve.

The cathode has the dimensions 12 13 x 0.5 cm and its two conductor rails 7 connected to it are each 5 x 20 χ 0.5 cm in size. The anode has the dimensions 13 χ 19 x C, 25 cm. In the plastic vessel 3 675 ml of an in-TTatriu ^ vreroxodisulfatlösung are filled. The open-circuit voltage is? .35 volts. In the case of a load with an external resistance R. = 2.5 CIm, a working margin TJ results. = 1.73 volts with a working current I. = 0.635 office) ere. The internal resistance is R _± = 0.976 Ohm.

The box-shaped cell was operated continuously for 78 hours across an external resistance of 2.5 ohms during the daytime and 20 ohms during the nighttime. When operating with 20 ohms, the working voltage U, = 1.9 volts, the working current I. = 0.092 amperes. A total of 29.84 Wn were delivered, which corresponds to an energy content of 28.15 Wh / kg. The total weight of the element was taken into account for the calculation. However, since the required water only needs to be filled in with such a filling element immediately before start-up, the energy content of the Oraktisch can be specified as 69.55 Wh / kg. The temperature rose to about 35 0 within the first hours. After 78 hours it was

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the performance of the cell has dropped sharply; it was because of that the used solution removed and through, an equal K narrow fresh 1 M sodium persulfate solution replaced- afterwards resulted practically the same performance values again.

The replenishment with active solution can be repeated until the magnesium code has decreased too much. The cathode can be used indefinitely. Depending on the dimensioning the anode can thus operate the filling element for a very long time where ^ i by continuously exchanging the reactant solution: operation without interruption is possible. To. No anode can be used if necessary.

By reducing the distance between the cathode and anode, for example in the case of dog cells with a Magnpsium cylinder As an anode, cells can be used for heavier loads and produce more frequent regeneration. Such a round cell with a content of, for example, 500 ml of 1 m-TTntriuToersulfntlösung delivers, as tests have shown, when operated with an external resistance of 1.2 ohms for 6 hours Labor saving from 1.88 to 1.6? Volts at currents of 1.25 "to 1.1 amps. A similar cell that runs at 0.6 ohms is operated, provides 1.725 to 1.57 volts for 4 hours at currents of 2.35 *> is 2.2 Anroere.

A battery consisting of two round cells connected in series with a content of? 20 ml of 1 m- ^ atrium sulfate solution supplies for operation with 4, 7 ohms for 3 hours and 20 minutes Voltages from 4 to 3.6 volts with currents from 0.8 to 0.7 Anvoere.

By adding small amounts of polar organic compounds, such as alcohols with a chain length of C- to C ₁ -, or of sulfones, such as dimethyl sulfoxide, the energy yield can be increased significantly

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to increase. The energy yield is also dependent on the Composition of the anode material, size and spacing of the Electrodes and the external load. Ss can keep ener ~ i up to about 50 V / h / kg can be achieved, if the weight of the used Water is taken into account. Without the water used, the energy content is up to 160 Wh / kg.

The filling elements according to the invention show up to now known filling elements have significant advantages, to which the simple structure of the cathodes and the use of "well-known" Metal alloys as anodes include, as well as the possibility of not only small but also large powerful cells and batteries to manufacture inexpensively. The realizable energy contents have high values. 'Taking into account the fact that the water to be filled does not have to be stored in the cells, this results in particularly high energy contents. The cells can be easily regenerated by exchanging or renewing the reactant solution and anodes. With the appropriate Such cells can be dimensioned for the anodes be operated for a longer period of time by simply renewing the used reactant solution, with a continuous Operation is possible if appropriate facilities are provided for the filling elements. The anodically developed Hydrogen can escape safely from smaller cells, destroyed or otherwise used in larger cells will. The reactant is in dry. Condition indefinitely durable and despite the high positive redox potential *) relatively harmless. The "solutions of the reactants are only weakly acidic to weakly alkaline; they are neither toxic still corrosive and therefore harmless to handle. The solutions used are also largely harmless to the environment. Whore at If relatively large quantities are discarded, their high mineral salt content should be taken into account. After all, yes

*) as well as the high oxygen content ^ ₆

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determine that the Frill el em ent "materials required are produced from virtually present in unlimited Kenge raw materials and the carbon material" existing cathode are unlimited usable so that the erfindun ^ sgemäßen J ¹ UlIeIemente in this respect advantageous electrochemical Stronouellen are .

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Claims (1)

S u t ty claims Λ . Galvanic Füllelernent Rait a liquid, katrodischer R ^ actants, characterized ψ, e ke η ~ ζ eichret that the k ^ ological reactant is an aqueous solution of a Peroxodisulf ° ts (persulfate) and bleit cathode at a reaction and A "(6 ) It is made of highly porous coal and is made up of material and at the same time forms the electrolyte of the filler element (1), the latter of which consists of a base (5) of a base element. 2. Galvanic F ^ llele-rent according to claim 1, characterized in that the Re ^ .kticns- and A "lead cathode (6) consists of a flexible, highly conductive, irrattenartifcen carbon body" of any shape, which is used to conduct current with Foriikbody ^ (7) AJS compressed carbon can be combined. 3. Galvanic filling element according to claim 1 or 2, characterized characterized in that the anodes (5) from on There were even Hagnesium readings. 4-, galvanic filling element according to claim 1 or 2, characterized characterized in that the anodes (5) from on known iron alloys exist. 5. GaI varisches F'51 IeI em ent according to one of claims 1 to 4 ·, characterized in that the anodes (5) are dimensioned so that they f-'rr several fillings of the element can be used with the reactants which are consumed. 709840/0197 _ ORIGfNAL INSPECTHD 6. Galvanic filling element according to one of claims 1 to 5, characterized in that as Peroxodisulfate (persulfate) Lithium peroxodisulfate is used. 7 · Galvanic filling element according to claim 6, characterized in that for dissolving the lithium peroxodisulfate Deionized water is used. 8. Galvanic filling element according to one of claims 1 to 5 ^ characterized in that sodium eroxodisulfate is used as feroxodisulfate (persulfate). 9. Galvanic filling element according to Arspruch 8, characterized in that for dissolving the sodium ■ oeroxodisulfat Water of any kind is used. 10. Galvanic filling element according to one of claims 6 to 9 »characterized in that the concentration the peroxodisulfates in water in the range of 0.1 molar until saturated. 11. Galvanic filling element according to one of claims 1 to 10, characterized in that the filling element (1) has a device for continuous feeding the pJaictanten solution is provided. 12. Galvanic filling element according to claim 11, characterized in that the filling element (1) with a Means for the continuous discharge of the used solution from the slenent is provided. 13 · Galvanic battery made of filling elements according to Claims 1 to 12, characterized in that the Filling elements in a manner known per se by "row and / or parallel connection are connected to one another. 709840/0197 3 · 1A-. Galvanic filling element according to one of Claims 1 to 13, characterized in that alcohols with a chain length of Cp to C _{1 in a} concentration of up to 5% are added to the solution of the reactant. 15 · Galvanic filling element according to one of claims 1 to 13, characterized in that the solution of the reactant dimethyl sulfoxide is added in concentrations up to 5%. 16. Galvanic filling element according to one of claims 1 to 15 »characterized in that the filling element (1) with a device for continuous Feeding the anode (5) is provided. 709840/01 97