CS214885B2 - Lead accumulator cell and method of making the said - Google Patents

Description

The essence of the invention of the lead-acid accumulator cell is that the active substance deposited on the support plate is composed of crystalline and polycrystalline lead oxide in which lead has its highest valency 4.

The process according to the invention consists in forming a continuous and adherent layer of lead on a lead, antimony lead alloy or inert non-conductive material covered with lead or antimony lead alloy. and cadmium, whereupon the carrier plate is immersed in a vessel containing a dilute sulfuric acid solution and a lead plate and connected to the positive terminal of the source of electromotive force, the lead plate being connected to the negative terminal of this source of electromotive force. lead-cadmium layer, with sulfuric acid, at the same time oxidation of lead in this lead-cadmium layer and formation of a mixture of crystalline and polycrystalline lead oxide in which lead has its highest valency equal to 4.

The lead-acid accumulator according to the invention is suitable for:. all applications that require the described new features.

The invention relates to a lead-acid accumulator cell and to a process for its manufacture. In particular, the present invention is directed to the active mass used in the manufacture of the electrodes of these cells and to a method of making the active mass.

The construction and operation of the cell are well known. The cell, both primary and secondary, is an electrochemical device consisting of two plates of conductive material immersed in an electrolyte. The primary cell is designed to generate electrical voltage and convert chemical energy into electrical energy in an irreversible manner. However, the operation of the secondary cell is reversible, so that the secondary cell can convert chemical energy into electrical energy and vice versa. Secondary cells are commonly called battery cells.

If the accumulator cell delivers electrical energy, it is said to discharge the cell in which chemical energy is converted into electrical energy. If power is supplied to the accumulator cell, the process is reversed and the cell is being charged.

Two or more cells connected in series or in parallel form a battery. A battery formed by combining multiple battery cells is known as a rechargeable battery. There are two main types of accumulator batteries: lead acid batteries or abbreviated lead batteries and nickel-alkaline (Edison) batteries, which are popularly called alkaline batteries. The invention relates to a first type of battery.

Lead acid battery cells consist of a positive lead of lead oxide and a negative lead of sponge lead, which are immersed in a dilute solution of sulfuric acid (electrolyte). The part in which chemical changes occur as the battery current flows is the active matter or material of each plate. The active material is deposited on a frame or grid of pure lead or lead alloy, for example lead-antimony alloy. The frame or grid serves two purposes, both carrying active mass and conducting electric current. In particular, the invention is directed to a new, particular and improved active substance.

The following reversible reactions describe the charging and discharging process of a typical lead acid battery:

charging discharging

PbO2 + 2H2SO4 + Pb ---- 2PbSO4 + 2H2O + plate - plate (anode) (cathode)

The active material of the positive plate is brown porous lead oxide, while the active material of the negative plate is gray, spongy porous lead in pure form.

Lead acid batteries, which are generally available on the market, have limited performance and capacity. Therefore, many attempts and suggestions have been made to improve these batteries. Improving the charging and discharging characteristics of these batteries, increasing the rate of current discharge, and reducing the internal resistance of the battery cells are just some of the parameters that have been the focus of attention to those skilled in the art. Some of them focused their attention on the electrodes, others designed electrolyte treatments to improve the performance of cells and devices containing these cells.

U.S. Pat. No. 2,933,547 discloses a battery made up of dry electrical cells consisting of silver and zinc electrodes and a solid electrolyte. A permeable plastic membrane is inserted between the electrodes to allow cation exchange.

U.S. Pat. No. 3,468,719 discloses a dry ion conductor made of a polycrystalline material whose structural lattice is composed of aluminum and oxygen ions, the sodium ion migrating due to the electric field in the crystal lattice. This material is used as a partition of cell halves in the battery construction, as described in more detail in Example 3 of this patent. U.S. Pat. No. 3,499,796 discloses a ceramic insert located between a pair of electrochemically and cationically conductive crystalline bodies between which cation exchange occurs and which are separated by a cationically conductive, electronically nonconductive crystalline body. The patent also discloses an accumulator composed of these components.

US-A-3,709,820 discloses an organic dry electrolyte consisting of a crystalline electron donor-acceptor complex comprising ionic crystals of 7,7,8,8-tetracyanoquinodimethane, an aromatic amine, and a crystal lattice impregnated liquid. The electrolyte described in this patent is used in capacitors to reduce their resistance.

U.S. Pat. No. 3,765,915 discloses the use of a ceramics of beta-modification of alumina as an electrolyte in cells or batteries of the sodium / sulfur type.

These patents represent only a small part of a series of patents that represent research activity and interest in this field. However, the basic design of the lead acid battery and its cells remained essentially unchanged. Lead acid batteries currently consist of a large number of cells (usually 3 or 6), as they were decades ago. The active mass of the positive plate is porous lead oxide, the negative plate consists of spongy porous oxide. the lead and electrolyte are dilute sulfuric acid.

The purpose of the present invention is to improve the accumulator cells and devices assembled therefrom.

The essence of a lead-acid accumulator cell comprising at least one support plate electrode of a material selected. from the group of lead, antimony lead and inert non-conductive substances coated with lead or cadmium or antimony lead alloy, the carrier plate being covered with an adhesive and durable active material layer according to the invention, characterized in that the active material is composed of of crystalline and polycrystalline lead oxide in which lead has its highest valency equal to 4.

The active material preferably contains a trace amount of metallic cadmium and is deposited on the positive electrode plate.

According to the invention, the process according to the invention is based on a lead, antimony lead alloy or an inert, non-conductive lead-coated material. or a lead-antimony alloy forms a continuous and adherent layer of lead and cadmium, whereupon the support plate is immersed in a vessel containing a dilute sulfuric acid solution and a lead plate and connected to a positive clamp. . sources of electromotive force, the lead plate being connected. to the negative terminal of this source of electromotive force, the electric current induces the reaction of cadmium in the lead-cadmium layer with sulfuric acid, at the same time oxidation of lead in this lead-cadmium layer and formation of a mixture of crystalline and polycrystalline lead oxide. in which he has his highest power equals. 4.

Continuous. and the adhesive layer of lead and cadmium is sprayed onto the surface of the support plate by spraying a hot molten mixture of lead and cadmium in a reducing atmosphere and sintered into the. the surface of the carrier plate without occurring. to form a lead-cadmium alloy.

The hot molten lead-cadmium mixture contains 30 to 70% lead by weight. A preferred embodiment of the process according to the invention is characterized in that the hot molten lead-cadmium mixture contains 45 to 55% by weight of lead. A particularly preferred embodiment of the process of the invention is that the weight ratio of lead to cadmium in the hot molten mixture of lead and cadmium is about 1: 1.

Another advantageous embodiment of the process according to the invention is that the continuous adhesive layer of lead with cadmium is formed from a relatively thin paste formed by mixing lead and cadmium with a reducing organic liquid, the paste being applied to a support plate and the solvent from the paste is evaporated. The reducing organic liquid may be methanol or ethanol.

Also, in a process in which the cadmium lead layer is formed from a relatively thin paste, it is preferred that the lead-cadmium layer contains 30 to 70% lead by weight. More preferably, the layer of lead and cadmium contains 45-55% by weight of lead. Particularly preferred is an embodiment in which the ratio of lead to cadmium by weight is 1: 1 in the lead-cadmium layer.

Another advantageous embodiment of the method according to the invention is that the continuous and adherent layer of lead and cadmium is formed on the surface of the support plate by electrolytic deposition by dipping two conductors, i.e. lead-antimony cathode and lead-cadmium anode into the electrolytic bath. which contains lead fluoroborate, lead metal, fluoroboric acid, boric acid, cadmium fluoroborate, cadmium metal, ammonium fluoroborate and water, whereupon the cathode and the anode are connected to the negative and to the other, respectively. positive terminal of the source of electromotive force.

Also, in a process in which an electrolytic coating is used, it is preferred that the coating be applied. when the anode is of a 1: 1 weight ratio lead-cadmium alloy. More preferred is an embodiment in which the anode. contains 30 to 70% lead by weight. It is particularly preferred that the anode comprises 45 to 55% by weight of lead.

The new and higher effect of the invention resides. in that lead accumulator. article has. Compared to conventional lead-acid battery cells, lower internal resistance and higher electromotive force. A further advantage of the lead-acid accumulator cell according to the invention is that it has a lead-cell battery cell. higher current charging and discharging capacity. and can. be charged at a much higher rate. Another advantage of the lead-acid accumulator according to the invention. rests. v. . that this article suffers considerably less from sulfatization.

The basis of the invention was an unexpected discovery of being useful. battery characteristics. Cells can be substantially improved if a special positive plate is provided in the cells with a crystalline and polycrystalline lead oxide active substance in the form of PbO2. . Lead crystalline batteries assembled from these cells have consequently been compared to conventional batteries. lead acid batteries significantly better performance.

In the following, the invention will be described in detail with reference to the construction of the accumulator cell and a battery made up of these accumulator cells. However, this description should not be construed as limiting the scope of the invention, since other accumulator batteries may also be constructed based on the described principles. batteries, which also fall within the scope of the invention.

It has been found that the accumulator cell constructed according to the invention achieves properties which were previously unattainable in the known types of accumulator cells. As a result, the accumulator batteries produced by the assembly of these accumulator cells have significantly better performance characteristics than conventional lead-acid batteries. These improved properties include, but are not limited to, lower internal resistance, higher activity, more advantageous charging and discharging characteristics, higher battery capacity, higher charging rate, and higher electromotive force per cell.

The particular active substance produced by the process of the invention consists essentially of crystalline and polycrystalline PbO2 in which lead reaches its highest valency of four, and sometimes called lead dioxide, to distinguish it from lead oxide in which PbO is only bivalent .

As used herein, the term "polycrystalline" refers to a cluster of individual crystalline formations of lead oxide, which crystals are at different stages of their growth or development. Thus, the active substance according to the invention is a mixture of individual crystalline PbCl 2 forms together with polycrystalline aggregates.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be further elucidated by means of an exemplary embodiment thereof, which is described by the accompanying drawings, in which:

FIG. 1 schematically illustrates a process for forming the active mass, i.e. crystalline and polycrystalline lead oxide of the present invention; FIG. 2 schematically illustrates the formation of positive and negative plates and the cell containing the plates; of the invention and a conventional lead acid cell.

Figure 1 shows a support plate 1, which is usually made of pure lead Pb or a lead alloy with antimony Pb-Sb. The support plate 1 is covered with a layer of lead and cadmium Pb-Cd, the method of depositing this layer will be described later. The support plate 1 so treated is immersed in a dilute sulfuric acid solution in the vessel 3. The support plate 1 used herein is typically a film of about 0.2 mm thickness and is made of a lead-antimony alloy. However, the thickness of the carrier plate 1 may be varied depending on the individual designs and the intended use of the battery.

Before immersion of the support plate 1 in a dilute sulfuric acid solution in the vessel 3, a hot lead-cadmium melt is applied to the surface of the film by means of a conventional spray nozzle or other suitable spray device. In this way, a continuous adhesive layer consisting of lead and cadmium is formed on both sides of the film. When spraying the hot melt onto the surface of the film, a reducing gas such as hydrogen is used. The sputtering is terminated when the thickness of the layer deposited on each of the surfaces reaches approximately 0.5 mm.

Again, this thickness can be varied depending on the individual designs, the desired resistance and the intended use of the device. The thickness of the lead-cadmium Pb-Cd layer on each of the surfaces can generally be selected in the range of 0.1 to 2 mm, preferably in the range of 0.5 to 1.2 mm. A layer thickness of approximately 1 mm is particularly preferred.

The lead-cadmium melt Pb-Cd is prepared from a cadmium wire of approximately 1 mm thickness on which a layer of lead is electrolytically or clad with a thickness of about 1: 1. The resulting wire is then melted and sprayed onto the surface of the film as described above at a temperature higher than the melting points of lead and cadmium but lower than the melting point of the particular lead-antimony alloy from which the support plate 1 is made. a mixture of lead-cadmium Pb-Cd on the surface of the carrier plate 1.

In order to increase the adhesion of the lead-cadmium layer to the surface of the carrier plate 1, the carrier plate 1 may be sanded for a few minutes to achieve roughening and thus an increase in surface so that the sintered lead-cadmium mixture will better bond to the film surface. It should be noted that the terms " foil ", " backing plate " and " header plate " are used interchangeably and refer to the lead-antimony alloy support plate 1 in this application.

FIG. 1 shows a container 3 made of a non-conductive material, such as glass, plastic, and the like, comprising a dilute sulfuric acid solution having approximately the same density as the solution of sulfuric acid used in ordinary lead acid accumulator batteries. The vessel 3 further houses a lead plate or lead plate 5, which serves as a negative electrode (cathode).

The collector or support plate 1 produced as described is immersed in the electrolyte (FIG. 1) and connected to the positive terminal of the 3 volt electric power source 7 (for example a battery), while the lead plate 5 is connected to the negative terminal of the electric power 7 Although a plurality of support plates 1 may be submerged in the electrolyte and suitably connected to the electric power source 7, the invention is further described and illustrated only as the preparation of a single positive plate, which contributes to clarity.

Once the electrical circuit described has been closed, the cadmium from the lead-cadmium layer on the support plate 1 reacts with sulfuric acid to cadmium sulphate, which as a porous sponge mass u214885 is deposited on the negative electrode 5. The water dissociates into hydrogen H2 and O2. Hydrogen appears in the form of gas bubbles on the surface of the negative electrode 5, while the oxygen reacts with the lead and rapidly forms lead PbO2 in the form of lead. crystalline and polycrystalline masses. Thus, the formation of the active mass is complete in a few minutes, after which the support plate 1 is removed from the electrolyte, rinsed clean - with water and dried. The electrode is now. ready for use in a lead crystalline battery or cell of the invention.

The crystalline and polycrystalline o-oxide active material is a dark brown to black material. The mass is hard, homogeneous, highly porous and has a considerably low internal resistance.

In the manufacture of the carrier plate 1 provided with active matter of crystalline and polycrystalline lead oxide, it is essential that the carrier plate 1 of lead-antimony alloy is covered with a layer of lead and cadmium which is sintered.

During manufacture, care must be taken to prevent the formation of a lead-cadmium alloy during sintering or sputtering of the lead-cadmium mixture onto the surface of the support plate 1. The presence of cadmium in the sintered matter is also essential, since cadmium - promotes or promotes the formation of crystals and polycrystals of lead oxide - PbO2. It should also be noted that although cadmium reacts with sulfuric acid in vessel 3 to form cadmium sulfate, which is removed from vessel 3, traces of cadmium still remain in the active mass.

In the construction of the lead crystal battery according to the invention, three identical support plates 1a, 1b, 1c, which have been produced in the manner described, are immersed in the container 9 shown in FIG. The design of the container 9 is similar to that of a lead acid battery container. The container 9 contains a dilute sulfuric acid solution, which is typically used in such batteries. Support plates 1a, 1c are connected together by conductor 11 and conductor 13 are connected to the negative terminal of a 3 V electric power source 15 (e.g., battery, battery charger, etc.), while the support plate 1b is connected to the positive terminal of the electric power source 15 by Once this electrical circuit is closed, lead oxide PbO2 is reduced on lead plates 1a, 1c to lead and these plates 1a, 1c are negatively charged. The lead oxide PbO2 on the support plate 1b does not chemically change and is charged positively. Thus, the lead plates will serve as the negative electrodes (cathode) and the lead oxide PbO2 plate will serve as the positive electrode (anode).

After several minutes, during which the cell is fully charged, the electromotive force source is disconnected and the electromotive force of the cell then decreases from about 2.9 V to about 2.4 V. At this value, the electromotive force remains substantially constant. The cell is now charged and stores the later energy - discharge.

If the cell produced in the manner described is combined with other cells, for example 3 or 6 additional cells, each comprising a plurality of plates (17 or 19) connected in parallel, a lead crystalline accumulator battery is formed which contains, depending on the number of plates in each cell. or - 57 plates. Of course, if necessary, more than three cells, for example 6 cells, and so on, can be connected in series.

The lead crystalline accumulator batteries according to the invention have significantly better properties compared to lead acid batteries. The lead crystalline accumulator battery containing 51 or 57 plates can be charged by 10 to 15 times the electrical current used to charge the lead acid batteries due to its low internal resistance. Thus, the lead crystalline accumulator battery can be charged much faster than a lead acid battery. Similarly, the discharging rate of a lead crystal battery is greatly increased, since it may emit electric current at a much higher rate than the lead acid battery.

Fig. 3 shows a discharge curve of a lead crystalline cell produced according to the invention. For comparison, the discharge curve of a typical lead acid cell is shown in FIG. The solid line in Fig. 3 represents the discharge curve of the lead crystalline cell and the dashed curve represents the discharge curve of the lead acid cell. A comparison of the two courses shows that during the first 16 minutes (i.e., approximately 80% of the discharge cycle), the electromotive force of the lead crystalline cell remains constant and then decreases very slowly from 2.32 - V to - 2.3 V. On the other hand, the electromotive force of the lead acid cell decreases monotonically from 2.1 V to 2.0 V in the same time interval. This difference is particularly noticeable for batteries composed of these cells and shows that lead-crystalline accumulator batteries the battery may hold a higher electromotive force than the lead acid battery, as a result of which the lead crystalline accumulator battery has more advantageous operating characteristics.

In addition, the lead crystalline battery according to the invention has a 10 to 50% higher capacity compared to conventional lead acid batteries. In addition, the lead crystalline cell can be more charged and discharged without subsequent reactions or self-discharge, as is common with lead acid cells. As a result, the lead crystalline accumulator battery has a higher charge capacity than a lead acid battery of comparable weight and volume. The cells produced by the method according to the invention have approximately 0.1 to 0.2 V higher electromotive force than conventional accumulator cells from which lead-acid batteries are assembled.

As previously described, sintered lead and cadmium were applied by hot sputtering to the collector plate surface, thereby depositing a homogeneous continuous and adherent lead-cadmium layer on the surface of the collector plate. Two other methods of depositing a lead-cadmium layer on the surface of a lead-antimony alloy plate will now be described.

In another method of the invention, a finely granulated mixture of lead and cadmium in a weight ratio of 1: 1 is dissolved in a suitable organic liquid, such as methanol or ethanol. The size of the individual granules is in the range of about 100 to 500 μη. The methanol is then evaporated, the plate is dried and the lead-cadmium mixture is sintered in a press at a temperature in the range of about 300 to 400 ° C for about 3 seconds.

Again, temperature and pressure must be carefully controlled during sintering to avoid the formation of lead-cadmium alloys.

The thickness of the lead-cadmium layer on the carrier plate · 1 can be controlled by selecting a suitable sieve and depositing a suitable amount of paste evenly over the surface of the plate. A lead-cadmium layer of approximately 0.5 mm thickness can thus be deposited on both sides of the support plates.

. After applying a layer of desired thickness, the carrier plate 1 is immersed in a container containing a dilute sulfuric acid solution. The lead plate described in connection with FIG. 1 is also placed in the vessel. Again, crystalline and polycrystalline lead oxide PbO2 is formed on the support plate surface again. Cadmium from the lead-cadmium layer reacts with sulfuric acid and is stored in the form of cadmium cdSC4, from which cadmium can be recovered and reused. The support plate (s) are then used to construct a lead crystalline accumulator battery. which has been described in connection with FIG. 2.

In another variant of the process according to the invention, the hard compact lead-cadmium alloy is deposited on the support layer 1 electrolytically in a fluoroborate bath. Two electrodes, one made from a lead-antimony alloy (cathode) and the other made from a lead-cadmium alloy (anode) in a 1: 1 weight ratio, are immersed in a fluoroborate bath of the following composition:

cadmium metal Cd 0,374 kg ammonium fluoroborate 0,25 kg water 4,564 1

The electrodes are then connected to the positive and negative terminals of a 5 V electromotive force source for 1 hour until a continuous cadmium and lead layer of approximately 0.1 mm thickness is deposited on each cathode surface. The source of electromotive force is then disconnected, the cathode is removed from the bath, rinsed clean with water and dried. In the production of three support plates with crystalline and polycrystalline carbon dioxide on the surface, three cathode support plates produced in the manner described are immersed in dilute sulfuric acid and subjected to the same treatment as described in connection with FIG. they are then used in the construction of a lead crystalline cell that has already been described in connection with FIG. 2.

It will be apparent from the foregoing detailed description that the lead crystalline accumulator battery of the invention has significantly better properties than the lead acid battery. In addition to several of the significant advantages already described, a lead crystal crystalline battery is usually about 15 to 30% lighter than a lead acid battery of comparable size and capacity and has about 25 to 30% greater capacity than a comparable lead acid battery size and weight. Its ability to absorb substantially greater amounts of energy over a substantially shorter period of time, which is due to a substantially lower internal resistance and higher activity, means that the battery of the invention is particularly suitable for vehicles requiring high acceleration, e.g. vehicles and automobiles and other electrically powered engines.

Lead crystalline accumulator batteries produced by the method of the invention suffer little or no sulfatization. This in practice means that batteries can be discharged to a state where their electromotive force is close to zero. In lead acid batteries, on the other hand, sulphation is more or less a general phenomenon, which means that lead acid batteries cannot be discharged to an electromotive force below 1.5 to 1.8 V, otherwise the lead grids carrying the active compound paste will become almost irreversible. sulfatizaci.

It should also be noted that the invention has been described and illustrated with a view to a particular embodiment. It will be apparent from the foregoing description that numerous changes and modifications may be made to the invention.

For example, instead of a lead-antimony alloy support plate, an inert non-conductive support plate (for example, of a suitable plastic such as polypropylene or cadmium boroborate Cd (BF4) 2 1.01 kg lead fluoroborate Pb (BF4) 2 3.7 kg can be used) metallic lead Pb 2.02 kg of fluoroboric acid (HBFa 0.031 kg of boric acid 0.25 kg) (to which lead or a mixture of lead with cadmium can be applied as described). Such carrier plates are noticeably lighter than lead-antimony alloy carrier plates, and consequently the resulting batteries will be considerably lighter:

In the foregoing description of the invention, the weight ratio of lead to cadmium was 1: 1. This proportion by weight of lead may vary between about 30 and 70%, preferably between about 45 and 55%. However, optimal results were obtained when the two components were used in a 1: 1 weight ratio. If lead is predominant in the mixture, for example 70% lead is used, the lead-cadmium layer will be softer and less porous, for example, if cadmium represents 70% by weight of the composition, the resulting lead-cadmium layer will be harder and more porous. Optimum hardness and porosity of the lead-cadmium layer is obtained when the weight ratio of the components of the mixture is about 1: 1.

Claims (18)

1. A lead-acid battery consisting of at least one support plate electrode of a material selected from the group consisting of lead, an antimony lead alloy and inert non-conductive substances covered with a layer of - lead or - lead alloy with - cadmium or - with antimony, the carrier plate is covered with an adhesive and durable layer of active material, characterized in that the active material is composed of crystalline and polycrystalline lead oxide in which the lead has its highest valency equal to 4. 2. The lead-acid accumulator element of claim 1, wherein the active matter comprises a trace amount of metallic cadmium. 3. The lead-acid accumulator element according to claim 1 or 2, characterized in that the active substance is deposited on the positive electrode plate. 4. A method according to any one of claims 1 to 3, wherein a continuous and adherent layer of lead and cadmium is formed on a support plate of lead, a lead-antimony alloy or an inert non-conductive lead-coated or lead-antimony alloy. whereupon the support plate is immersed in a vessel containing a dilute sulfuric acid solution and a lead plate and connected to the positive terminal of the source of electromotive force, the lead plate being connected to the negative terminal of the source of electromotive force, causing electric cadmium reaction in lead-cadmium at the same time oxidation of lead in this lead-cadmium layer and formation of a mixture of crystalline and polycrystalline lead oxide in which the lead has its highest thickness equal to 4. 5. The method of claim 4, wherein the continuous and adherent layer of lead and cadmium is applied to the surface of the support plate by spraying a hot molten mixture of lead and cadmium in a reducing atmosphere and sintered into the surface of the support plate without forming a lead alloy. with cadmium. 6. The process of claim 5 wherein the hot molten lead-cadmium mixture comprises 30 to 70% lead by weight. 7. The process of claim 5 wherein the hot molten lead / cadmium mixture contains 45-55% lead by weight. 8. The process of claim 5 wherein the weight ratio of lead to cadmium is about 1: 1 in the hot molten lead-cadmium mixture. 9. Method. according to claim 4, characterized in that the continuous and adherent layer of lead with cadmium is formed from a relatively thin paste formed by mixing lead and cadmium with a reducing organic liquid, the paste being applied to a carrier plate and the paste solvent was evaporated. 10. The process of claim 9 wherein the reducing organic liquid is methanol. 11. The process of claim 9 wherein the reducing organic liquid is ethanol. 12. The method of claim 9, wherein the lead-cadmium layer comprises 30-70% lead by weight. 13. The method of claim 9, wherein the lead and cadmium layer comprises 45-55% lead by weight. 14. The method of claim 9 wherein the weight ratio of lead to cadmium is 1: 1 in the lead-cadmium layer. Method according to claim 4, characterized in that the continuous adhesive layer of lead and cadmium is formed on the surface of the support plate by electrolytic deposition by dipping two conductors, i.e. a lead-antimony alloy cathode and a lead-cadmium anode. to an electrolytic bath containing lead fluoroborate, metallic lead, - fluroboric acid, boric acid, cadmium fluoroborate, metal cadmium, ammonium fluoroborate - and water, whereupon the cathode and the anode are connected to the negative and to the other, respectively. positive power supply terminal, electromotive force. 16. The method of claim 15, wherein the anode is of a lead-cadmium alloy in a weight ratio of about 1: 1. 17. The method of claim 15, wherein the anode comprises 30 to 70% lead weight. 18. The method of claim 15 wherein the anode comprises 45 to 55% lead by weight.