DE2255845A1 - BIPOLAR ELECTRODE FOR ONE CELL OF A SECONDARY BATTERY WITH HIGH ENERGY DENSITY - Google Patents

Description

Bipolar electrode for one cell of a secondary battery with high energy density

The invention relates to a bipolar electrode for a cell of a device for storing electrical energy Energy ο

High energy density batteries that are rechargeable, light in weight have already been made (They deliver at least 50 watt hours per 453 g (= 1 am. pound) or more) and from easily accessible Materials are madeo Lately is various an attempt has been made to determine the ratio of work capacity to weight, the work parameters the battery and its reliability to improve batteries of this type for driving electric automobiles to make suitable. Batteries with a high energy density have also been proposed, '

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which use zinc / chlorine and zinc / bromine systems, some of these batteries containing electrodes made of graphite or porous carbon. While such batteries are useful in generating power and having satisfactory work capacity to weight ratios, difficulties have been encountered in their use. The contact between the halogen and the positive electrode was often insufficient and the ratio of work capacity to weight often left a lot to be desired »One of the proposals to improve the working parameters of the battery and its reliability in order to make such batteries suitable for driving electric automobiles, is the subject of US patent application 50 054 dated June 26, 1970. Bipolar electrodes have already been proposed as a simple means of operating rechargeable batteries with high energy density. Difficulties have been encountered in those systems in which a gas is available for unloading because this gas causes clogging of the flow channels. In addition, foreign gases, such as hydrogen, which are released during discharge, can form a locking bar. The object of the invention is to

reasons to overcome these disadvantages »

This task is solved by a bipolar electrode,

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which is characterized according to the invention in that it consists of a gas- and electrolyte-impermeable wall and a porous body on one side of the Wall is held and has several passages for passing an electrolyte from the Wall and the porous body are limited and extend across the wall almost over its entire length, and that the porous body is permeable to the electrolyte at right angles to the wall.

The invention also relates to batteries with high energy density and their cell components, which contain, as an important new feature, bipolar electrodes with an impermeable wall, preferably made of graphite, on the outside of which a strongly electropositive metal and on the inside of a porous anode or a positive body, preferably made of carbon (including porous graphite), the porous body forming with the wall a plurality of passages through which an electrolyte can pass through the porous body and enter the reaction zone of the cell. The other electrode of the cell is a strongly electropositive metal, e.g. zinc, on the impermeable wall of an adjacent bipolar electrode _{or the like}

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During the charging of the cell, zinc is deposited on the impermeable wall, for example by plating the negative electrode (cathode) made of a zinc chloride lead electrolyte, being connected to the positive during plating Electrode (anode) chlorine is released. Y / uring the discharge is a zinc chloride solution that is dissolved and contains gaseous chlorine, passed through the cell and electricity is generated as the zinc dissolves, to form zinc ions, and chlorine is converted to chloride ions. The electrolyte is then re-enriched with chlorine and fed back into the cell for further power generation. Instead of the cell and those from it To electrically charge existing cells, this can also be done by replacing the metal (preferably Zinc) - parts on the electrodes are "refueled".

Particular reactants, structural materials, and variously shaped electrodes are also included of the invention - as well as the cells and batteries made therefrom and methods for generating electricity.

To clog the electrolyte passages with gas eliminate or mitigate, are in a preferred embodiment of the invention in the upper range of

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Electrolyte through holes drilled, eliminating the held Gas can escape.

The invention therefore consists - in summary - in dai3 a bipolar electrode for a cell of a battery of high energy density from an impermeable Wall, a highly electropositive, often plated-on metal on one side of the wall, a porous body composed on the other side of the wall and several of the wall and the porous body limited passages is through which an electrolyte, e.g., an aqueous metal halide, is an elemental halogen contains, can pass through. The electrolyte is also able to pass through the porous wall, in particular from porous Carbon, through into a reaction zone between this wall and the metal part of another such electrode to enter. Through the overall reaction of the elemental halogen and the metal to form the metal halide des Electrolyte is generated by electricity

A preferred embodiment of the electrode according to the invention has a passage for an electrolyte, is dissolved in the gas, with one side of the electrode having holes for the discharge of undissolved gas »

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The invention is explained in more detail below with reference to the drawing. Show Karin

Pig. 1 is a vertical section through the middle of a pair of "bipolar electrodes according to the invention. which form a cell, with the flow of electrolyte into the electrode, through it and into the reaction space of the cell shown is j

Pig. 2 a side view of the electrode, of the metal-coated one seen from here »

Pig. 3 shows a plan of the Pig electrode. 2 who the Figure 8 shows the flatness of the electrode and the passages located therein; and

Pig. 4 is a front view of FIG. 1 along the section line 4-4, which is the face of the impermeable electrode with the holes in its upper part shows"

The electrolytic cell according to iPig. 1 has two bipolar Electrodes 13 and 15 with a seam 11 between the sheet metal

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dull, which is used for the electrolyte flow. The electrodes are clamped in a frame "or in a cell vessel (not shown) and are connected to an electrolyte supply line 17 and a discharge line 19. Each electrode has a gas- and electrolyte-impermeable wall.21 made of graphite, which extends vertically And on the outer surface of which, after charging or thanks to the secondary "battery to which the cell belongs, there is a coating or a plated layer 23 'of a highly electropositive metal, for example zinc. The inner surface of the impermeable wall is connected to a porous electrode base body 25 by an electrically conductive resin adhesive layer 27. Some suitable adhesives have been suggested in the United States patent application by Carr et al. Relating to a conductive adhesive for an electrode in an electrical storage device. This United States patent application has the same priority date as the present application (internal file number U 10 081). The porous body "includes a plurality of vertical passages 29, which are also shown in the I ¹ Xg. 2 and 3 and through which the electrolyte can pass and that usually from the bottom to the top of the electrode, as illustrated in the drawing, because

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the porous carbon body has pores or passages which extend from its vertical passages facing inside up to its outside facing the reaction zone of the cell, penetrates the electrolyte, when it is pumped into the line 17 by means of a pump (not shown), the porous body 25 and enters the reaction zone 31. As a result of dea the pressure exerted by the pump, the electrolyte flows vertically upwards and out through the discharge line 19, in which it mixes with other electrolytes that come from other cells. After enrichment with chlorine the electrolyte passed between the electrodes again. It is desirable that the impermeable wall Compared to the porous electrode it is relatively impermeable ο The electrolyte can pass through the impermeable electrode over time Leak through the wall, but the flow rate through the impermeable wall will be much less than which be through the porous body.

An important feature of the invention is that the inner surface 55 of the carbon porous body 25 in constant contact with dissolved chlorine contained in the electrolyte passing through the porous body enters the reaction zone. No boundary layer off

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resting electrolyte separates the electrode surface from chlorine, as it might if the electrolyte would only enter the cell at the bottom of the reaction zone ο -. .

By creating an excess of electrolyte at the inlet of the passages 29, the passages are always filled, the electrolyte resting on the porous carbon body and the lack of halogen in the upper cable of the cell are prevented, the desired direction of the electrolyte influence is maintained and prevents undesired backflows _o The proportions of the electrolyte can be adjusted with suitable means, for example by means of "valves (not shown) or by the pump pressure or the pump capacity.

Several of the cells described above can be combined in series to form batteries and these can continue be connected in series to increase the voltage, · parallel to increase the current output, or mixed in series and in parallel to achieve both. Manufactured according to the description and drawings Batteries have an improved work capacity to weight ratio, usually over 50, especially

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preferably over 100 Y / att hours per 0.45359 kg (1 am. pound) with a theoretical upper limit of 185 watt hours per 0.45559 kg, using a zinc chloride solution in which the ZnCl ₂ : HpO ratio is about 1: 8 . Such batteries are strong and suitable for use in cars and trucks, where they are "resistant to the usual vibrations which are associated with the use in these vehicles. Oie also have a long life, are relatively idle easy to manufacture, being easily accessible Materials are used, are easy to recharge or are easy to provide with new fuels and are effective and economical in operation. One of the most important advantages of the batteries, cells and electrodes according to the invention, which are made from the special materials and a special electrolyte, is light weight and even passage of the electrolyte through one of the walls of the bipolar electrode.As indicated by arrows 35, the passage of the electrolyte occurs completely uniformly over the entire length of the porous carbon body, while arrows 37, the size of which decreases from bottom to top, the Volume acceptance of the in d en passages 29 indicate flowing electrolyte. Arrows 39 accordingly show the increasing volume

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of the electrolyte as it flows through the reaction zone 31. It is evident that without the special mechanism for charging the surface 33 with chlorine-enriched electrolyte, the generation of electricity in the upper electrode area would decrease because of the loss of chlorine from the electrolyte flowing upwards. Such a one. uneven generation of electric potential at different points of the electrodes would even lead to inefficient operation, for ^r üeil to internal short-circuits. '

The frame or the cell vessel, which receives the components of the cell according to the invention, expediently exists made of an electrically non-conductive plastic, preferably made of polyvinyl chloride, PVDC, phenol-formaldehyde resin, chlorinated polyester, acrylonitrile butadiene styrene resin, polypropylene or polyethylene, it but can also consist of hard rubber or some other suitable IsolieTiumaterial that protects against damp chlorine and aqueous metal (zinc) salt solutions are stable. Preferably, the cell vessel is designed to accommodate multiple, e.g., 10 to 30, bipolar electrodes can, supply and discharge lines being provided for these electrodes. In some embodiments

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the cell vessel is divided into sections which, together with the electrodes, form battery units by means of pressure be held together. Some of these forms resemble a frame and decking Filter press by placing non-conductive spacers between the electrodes to keep the spaces within the cells and prevent short circuits due to mutual contact of electrodes. It is natural known per se how to design and manufacture suitable cell vessels in order to use them and the inventive To manufacture cells batteries in which the electrolyte circulation is ensured.

The impermeable wall that is usually perpendicular may be of any material suitable for having a metal electrode attached to it, Can be deposited or plated »Although synthetic resins and various types of rubbers are used it is advantageous to use carbon in a form that is sufficiently impermeable to allow the deposition of a uniform metal coating on the outside thereof without this metal coating by pressure inside the cell or pressure of the electrolyte is loosened because of this pressure by the

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TiTand. is not given. In some cases it can Porous carbon can be used, the outer surface of which has been treated with resins to make it suitable for To make gases and fluids impermeable. Preferably However, graphite is used because graphite is an excellent conductor does not react with the electrolyte and quickly with the metal of the electrode surface plated or otherwise connected. Although the thickness of the impermeable wall the existing electrode part is arbitrary, the Gfcräphitwand generally 0.1 to 2.5 mm, preferably 0.1 to 1 mm thick. The size of the electrode itself can be lie somewhere in a wide range, but electrodes with an outer surface area (correspondingly a simple, platable outer surface

p ρ

marriage) - from 30 to 1000 cm, preferably from 100 to 400 cm,

used, which is typically 5 "to 1000 amps per .929 cm (= 1 am. Square foot), preferably up to 1 A / cm, discharged. . '

The porous part of the electrode is about the same size and shape as the impermeable wall, see above that it is designed to fit the wall and

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together with it can form internal passages through which the electrolyte can enter the reaction zone of the cell. usually, is the porous component made of graphite or activated charcoal of animal or vegetable origin, which is known per se and has an extremely large ("inner") surface »The porous component can also be removed by burning or pyrolysis of oil or gas extracted carbon. In addition, other well-known Electrode materials are used, provided they are electrically conductive and sufficiently resistant to the environment or are inert, e.g. sintered titanium or rutile with a noble metal or oxide catalyst, e.g. platinum or Ruthenium oxide. The use of finely divided particles with a high surface improves the contact of the dissolved chlorine with the inner surface of the porous slectrode body, which forms one wall of the cell. The porosity of the base body, hereinafter referred to as carbon, since this is a preferred material, results from the fact that 20 to 80 $ of its cross-section is filled with carbon, while the remainder is made up of pores that allow the passage of the electrolyte. The carbon content is preferably between 30 and 60%. The porous carbon can be made from granules

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or powders of various' particle sizes made of activated or other carbon. By selecting the particle sizes and the proportionate amounts of resin the dimensions of the passages and the carbon content of the body can be adjusted »Usually Resins are used to "form the carbon". These resins can be burned off or after they have set be removed chemically, creating ways for the • The passage of the electrolyte is created. Suitable Electrode materials "are in the Kirk-Othmer ^" Encyclopedia of Chemical Technology "(2nd ed.), Volume 4, page 58,".

Typically, the pores or passages in the porous carbon have an average diameter of 5 to 500 microns, preferably 10 to 100 microns, especially 25 to 50 microns, in _o The minimum cross-sectional thickness of the porous carbon (transverse to the outer surface of the Slektrodenwäne) is between 0, 5 mm to 4, "mainly be 0.5 to 2 mm ο the wall made of porous carbon ~ em to turn at its thickest point as thick as the graphite wall to five times _o

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Although either the impermeable wall, below referred to as graphite because this is the "preferred material, or the porous carbon body is hollowed out or can be provided with grooves so that they have a variety contain vertical passages for the electrolyte, it is usually preferred to use the porous carbon, e.g. by compression molding, so that it has the passages of the passages connected to the cementing of the graphite wall with the porous carbon body, the Passages are only present as grooves in the surface of the porous carbon before cementing. The number the passages are generally between 5 and 25 »their dimensions are between 0.5 and 2 mm deep and 0.5 and 5 mm width. The width to depth ratio of the passages is generally in the range 2: 1 to 10: 1. The porous carbon is attached to the graphite wall with any suitable adhesive, preferably with a polymer resin which can be either thermosetting or thermoplastic »Zu

suitable resins include those which are inert to their environment, e.g., epoxy resins. The thickness of the Resin will normally be very little, for usual

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borrowed from 0.01 to 0.5 mm, which gives the best results. The resin usually covers the entire contact area ₀

It should be emphasized that the grooves could just as easily be made in the impermeable electrode. However, it is more advantageous if the grooves are in the porous electrode, because it is wider than the impermeable electrode and therefore structurally more robust ₀

The highly electropositive metal that is deposited on the outer graphite surface while the battery is charging can be made by passing direct current through a metal halide electrolyte, which with is in contact with the battery electrodes, any suitable metal with a sufficiently high electromotive force can be used Be a power that is sufficient to generate a sufficiently high battery voltage with the halogen used, 'e.g. Metals of groups II B and YIII of the periodic table. Though iron, cobalt and nickel are enough have high emf, zinc is the most preferred and most suitable metal as it is the most "practical" EIvIK and has the lowest comparable weight. Other suitable metals are in the United States patent application 50 054 with the designation "Halogen Hydrates"

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and proposed in a US patent application entitled "refuelable Electrical Energy storage device" (internal iikteneaeichen U 10 053) that the same priority date as the present application has _o On "both applications is hereby expressly incorporated lie ζ ug.

The zinc layer on the graphite electrode is normally 25 "to 4000 microns thick, preferably 100 _N to 1500 microns. However, there may be cases where it is useful to use other thicknesses and when other metals are used, the thickness ratios are similar.

The electrolyte is a metal salt that corresponds to the metal used as one of the electrode surfaces and the halogen used. Although some embodiments of the invention may employ bromine as the halogen, the use of chlorine is particularly preferred. As a result, the electrolyte sala will usually be zinc chloride. In the electrolyte, the concentration of metal halide in the aqueous medium can be between about 0.1 i * and saturation.

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registration 50 054 is to be compatible with struck storage of halogeruaydrat, a "preferred range of the metal chloride concentration is between 5" and 50 °, in particular between about 10 and about 35 °

The zinc / chlorine / zinc chloride system is technically superior to a system based on bromine because Chlorine is lighter than bromine, which contributes to the battery's "high energy density" and because chlorine is used during charging the battery can be more easily removed from the electrolyte. The lower solubility of chlorine in the electrolyte lowers the diffusion of chlorine towards the zinc electrode (in comparison to bromine), from which a lower level of self-discharge with the zinc results. Chlorine escapes because it is gaseous and can easily be recovered, preferably as a hydrate of chlorine, from which chlorine can be released as soon as the battery is discharged and the supply of Electricity to external motors etc. is desired.

The concentration of zinc chloride in the electrolyte is usually between 15 and 35%, both during the Charging as well as during discharging, the higher concentrations being at the beginning of charging and during discharging occur o

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? / R R R Λ

The temperature of the electrolyte may vary over a wide range, but it is usually zwisehen O ⁰ C and 80 ⁰ C, preferably between 1 5 ° C and 4O ⁰ C. The pressure is 0.5 ms 10 atm, preferably 0.8 to 2 atm, in particular 1 atm + 10 ^a / o .

Although other materials in the electrolyte are not required to make the battery operational, It is advisable to add substances that promote the deposition of zinc on and its removal from the cathode control by preventing dendrite formation. Such additives are in a US patent application with the Name "Battery Electrolyte Composition", the internal one File number U 10 079 and the priority date of the present application has been proposed.

The battery is switched on by placing a saturated or nearly saturated zinc chloride solution containing between 0.1 or 0.2 and 3 volumes of chlorine at a temperature of 15 to 40 ^° C., preferably at about 30 ° C., in the passages of the electrodes between into the layers of impermeable and porous carbon and through the pores of the porous carbon into the reaction zone of the cell - all in one

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ORIGINAL INSPECTED

Measures that the linear velocity in the upward direction is between 2 and 100 cm / second. The pressure difference to generate this flow is in the range of about 0.01 to 1 kg / cm. The cell voltage generated is around 2.1 "V in the open circuit and the fully charged battery has a working capacity γόη of around 5000" Wh _{0 with around 125 cells}

After the electrolyte streams have passed through the reaction zone, they are mixed together and additional chlorine is dissolved in the electrolyte to achieve the desired level, e.g. about 2 to 3 vol. The chlorine is preferably supplied from chlorohydrate and in some cases, for example, chlorohydrate can enter the SLIe with the electrolyte and release its chlorine there. The use of chlorohydrate is particularly preferred because the water added with the chlorine decreases the zinc chloride concentration that has been increased by the dissolution of some zinc and the ionization of chlorine during a previous passage of the electrolyte through the reaction zone so that the zinc chloride concentrations remain reasonably constant. The hydrate can be produced by processes described by the inventors in an ^Ü 8A patent application with the

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ORSGWAL II

27RF8A5

drawing "Manufacture of Chlorine Hydrate", the priority date of the present application and the internal File number 2802 or in U.S. Patent Application 50,054 have been suggested.

The fumigated electrodes make it possible during the discharge according to a preferred white embodiment of the invention, that the undissolved gas, preferably gaseous Chlorine, enter the porous electrode through openings or holes 40 and into the conduit 19 for circulation reach. This causes a constant flow of gaseous chlorine that is not dissolved in the electrolyte the circulation system. Generally the holes have in the electrode sizes from about 0.1 to 3 mm, preferably 0.5 to 1.5 mm and particularly preferably 0.7 to about 1.3 mnu of electrolyte wetted with dissolved gas normally the porous electrode, so that the gas bubbles not dissolved therein cannot pass through the porous electrode can pass through. The openings or holes in the upper part of the electrode therefore allow the gas to to escape into line 19 to circulate again »

After the battery is discharged, its cells are recharged, by using a direct current source

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ORIGINAL INSPECTED

the voltage is connected to the electrodes, where the positive pole of the power source with the electrode

porous carbon at one end of a block of several bipolar electrodes and the negative pole of the power source is connected to the impermeable graphite wall at the other end of the block. The current is allowed to flow until a sufficiently thick zinc layer has formed on the graphite wall, as a result of which the full load is indicated. The chlorine developed on the porous electrode base body during charging is removed and easily converted into hydrate of chlorine, in which form it is a source of chlorine when the battery is to be discharged. The zinc ions from the zinc chloride electrolyte are converted into metallic zinc, which is deposited on the side of the impermeable graphite electrode adjacent to the reaction zone. After passing through the reaction zone , the exhausted zinc chloride electrolyte comes into contact with a more concentrated zinc chloride solution or with solid zinc chloride, where it absorbs additional amounts of salt and regains the desired high salt content. Instead of plating in situ, the electrodes, cells or cell blocks can be replaced by new or refreshed elements as soon as the battery

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battery is almost discharged. The removed parts can be freshened up and then used as replacement parts at the following "Refueling" operations can be used as described in the United States patent application entitled "Refuela" ble Electric Energy Storage Device ", the internal file number U 10 055 and the priority date of the present Registration has been proposed.

The batteries produced in this way deliver electricity evenly after being switched on and are almost completely maintenance-free. If desired, a diaphragm can be placed between the porous carbon and the zinc to prevent contact between the chlorine and zinc. Although this increases the efficiency of the cell, the cells work satisfactorily even without diaphragms, which is why these are often omitted in the narrow cells of the present invention, any tendency of cheap diaphragm materials to sag, swell, stretch or crumble, disrupt the flow of electrolyte and render the cell unusable.

The invention is illustrated by the following examples

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explained in more detail. In it are given all-.e parts in parts by weight and all temperatures in ⁰ C, unless specifically noted. "

example 1

A bipolar electrode for a cell of a secondary battery high energy density is produced by an impermeable graphite layer to a preformed one porous carbon body (porous graphite · can also be used) glued and the impermeable Graphite is coated with a layer of a highly electropositive metal. The elec-

2 trodes are square with a surface area of around 170 cm. , are about 3 mm thick and are glued together with an epoxy resin ester adhesive that is resistant to the electrolytes used and to chlorine. The porous carbon, including the passages it contains, is now about 2.5 thick and the graphite is about 1/5 the thickness of the carbon. The passages are cut into the porous carbon to about half its thickness and. extend as in J ¹ Ig. 2, almost to the end of the electrode. They are rectangular and about twice as wide as they are thick. Of the

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Graphite is a non-porous graphite that is designated as ATJ by the manufacturer (Union Carbide Corp.). This graphite is of limited porosity (almost non-porous) and of fairly hol: he density, different; it was filled with resin and baked several times until it had sufficient light and gas impermeability. The porous araorphic carbon used is designated by the manufacturer (Union Carbide Corp.) as "Grade 45" or Grade 60. "The porosity of the carbon is such that 45 to 50 -fr are empty and the pore sizes range from 25 to 50 microns.

The electrolyte used is an aqueous zinc chloride which contains about 3 g / l of dissolved chlorine during the discharge of the cell. At the beginning of the discharge the electrolyte has about 15 ^! / ° Zinc chloride and on discharge this content has risen to about 35 '"fr . On the other hand, the electrolyte has 35" p zinc chloride at the start of charging and about 15 ' fr ' zinc chloride when fully charged. When discharging, the cell develops 2.1 V with an open circuit and 1.65 Ms 1.7 V at 8 A. An impurity of 24 cells, which are electrically connected in series and provided with common electrolyte supply and discharge lines , develops 50 V "open circuit and 40 V below

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a load of 8 A. While the battery is being charged, the electrolyte flow rate is approximately 600 ml per cell per minute and about 400 ml per cell per minute during discharging.

To start up the cell shown in the drawing, electrolyte (35 $> zinc chloride) is pumped through the anode made of porous carbon into the reaction zone of the cell with the aforementioned charging flow rate.

Typically in this example the pressure is maintained at about atmospheric pressure with an additional suction pressure to maintain flow of about 0.07 to 0.14 kg / cm ² (about 1 Ms 2 am. Pounds per square inch).

With about 60 V of voltage applied to the battery is, or about 2.5 V voltage that is applied to the single cell, the cells are circulating of the electrolyte is charged, causing chlorine to be released on the surface of each porous electrode and on the Graphite surface of each cathode zinc is deposited. Charging generally takes 2 hours, after which time zinc will settle in a flat layer of about 200

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itiikron thickness should have deposited, instead of in situ To load, such a zinc coating can also be attached to a graphite base in another way or plating outside the operating cell. Then the cell is ready for use (for Unloading).

During use, aqueous electrolyte with a zinc chloride concentration of 15 ° F , containing undissolved chlorine in an amount of about 3 g / l, is driven through the cell at a rate of about 400 ml per minute, the electrolyte penetrating the porous carbon and enters the reaction zone. An open circuit voltage of around 2.1 V per cell is generated, which corresponds to around 1.7 V per cell at 8 A. As indicated by the different sizes of the arrows in Fig. 1, the flow through the porous carbon is uniform, while the flow in the reaction zone increases as the head of the cell approaches. The electrolyte is changed approximately every 2.5 seconds.

After the electrolyte has flowed through the cell while discharging and the dissolved chlorine has been consumed, is

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is he going through. Saturation is refreshed with chlorine and returned to the cell, where the discharge operation continues. When discharging, the zinc in the cathode will be dissolved, as will the chlorine in the electrolyte driven through the porous anode, and the concentration of zinc chloride will approach 35 ° / ^a , at which point the discharge is usually complete and the cell is recharged or must be. The reverse reactions naturally occur during charging. During discharging, the total electrolyte flow can be reduced to about 70% of the total flow during charging.

In the most advantageous use of the cells in accordance with the invention, some batteries are made up of these cells used, dirty electric truck with about 50 km / h (about 30 am. miles per hour) over 160 km (over 100 am « Miles). Then either the batteries are exchanged or charged in a charging station, or their electrodes held together by a framework (or cell vessel) are in every battery replaced. Then the removed electrodes are reloaded with zinc ("refueled") and then installed in another bacterium »

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2755845 - 30 -

The time required for such a "refueling" is minimal, it is usually only 5 minutes, which includes checking the density of the electrolyte and its partial replacement, checking the chlorine concentration and refilling of chlorine hydrate, as well as replacing the electrodes. Compared to a similar battery, the electrodes of which are non-porous and in which the electrolyte is introduced directly into the reaction zones at their bottoms, greater degrees of charging and discharging are achieved when the devices and methods according to the invention are used. This is probably aa improved contact of gaseous chlorine with the anode surface, which resides in that the chlorine brought by penetrating the pores of the amorphous carbon and the passages in intimate contact therewith through surface v / ith _o

Example 2

The measures in accordance with Example 1 are repeated, the conditions being, however, modified such that the electrolyte Niekelchiorid and the electropositive metal is nickel "The batteries are heavier and the efficiency 'of the power generation is lower but such batteries are quite useful when some Wants to sacrifice advantages.

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ORIGINAL WSPECTED

If the dimensions of the cell are changed so that the reaction zones are twice as thick, the battery size must be increased and therefore such cells as those mentioned in Example 1 are not as advantageous. Neither modifications of the nature of the porous amorphous carbon beyond the porosity range from 30 to 60 fo , nor operation at temperatures other than 30 ^° C., as in Example 1, in the range 20 to 40 ° C. seriously affect the efficiency. If the amorphous carbon used has larger pores, the suffering and discharging efficiencies decrease so that a marked drop in efficiency is noticeable when the pores are larger than 300 microns in diameter. This is also the case if the circulation in the reaction zone is kept so high by increasing the pressure with which the electrolyte passes through the pores that the pores are widened so that gaseous chlorine comes into contact with the zinc electrode.

The invention is based on the drawing and the examples has been explained in more detail, but it is of course not limited to these, as for the individual According to the invention features or measures equivalents can be used without affecting the inventive concept

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Pa

is thereby left. In this sense it should be noted that "with the porous graphite electrode according to FIG. 4 a small hole (1.2 mm = 3/64") in each passage on the head have brought the same. These holes allow any gas that gets into the stack or block to escape can, so that a blockage from or by gas in the channels is prevented. There will be similar tensions obtained with an open circuit and at different discharge speeds as in Example 1.

The invention can also be applied to other cell systems, for example those of the zinc / alkaline type (Zincate) / oxygen, but the zinc / zinc chloride / chlorine systems appear much cheaper. In addition, equally good results are achieved if the holes are in of the electrode are 0.8 mm (= 1/32 ") in size«

The holes for the escape of the gas can also be in the impermeable electrode instead of in the one preferred for this purpose be attached porous electrode. The weak part of holes in the impermeable electrode is that electrolyte could then flow into another cell, which can lead to internal short circuits. By The arrangement of the holes in the porous electrode maintains the characteristics of the individual cell.

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Claims (1)

- 33 patent claims s 1. Bipolar electrode for one cell of a device for storing electrical energy, characterized in that it consists of a gas- and electrolyte-impermeable wall (21) and a porous body (25) ", which is held on one side of the wall and several passages (29) for passing through of an electrolyte, bounded by the wall and the porous body "and extending across the wall extend almost its entire length, and that the porous body at right angles to the wall is permeable to the electrolyte. 2. Electrode according to claim 1, characterized in that the impermeable wall (21) consists of graphite, a coating (23) made of a strongly electropositive metal is arranged on the side of the wall which is opposite the wall facing the porous body (25) , and the porous body is made of a type of carbon selected from the group consisting of amorphous carbon and graphite, and has a unitary structure with such a porosity that a cross section contains between 20 and 80 ° carbon, the - 34 309821/0797 Pores, in, or passages through, the porous carbon an average diameter of 5 ms 300 microns and the minimum thickness of the porous carbon is between 0.3 and 3 mm. '-j. Electrode according to Claims 1 and 2, characterized in that the graphite wall (21) is 0.5 to 4 mm thick, the porous wall (25) made of carbon is one to five times as thick as the graphite wall that it is transversely over the walls extending passages (29) for the electrolyte flow are arranged essentially straight, perpendicular, parallel to one another and in the porous carbon body, and that the porous carbon body is attached to the graphite wall with an electrolyte-resistant adhesive (27). 4. Electrode according to claim 2, characterized in that the metal coating (23) consists of a metal of the groups II B and YIII of the periodic table. 5. Electrode according to claim 2, characterized in that that the metal in the metal coating (23) is zinc. 6. Electrode according to claim 1 to 3, characterized in that that one of the walls (21, 25) of the electrode has holes 309821/0797 (40) for the passage of the undissolved gas portion, which is carried along by an electrolyte in which gas is dissolved. 7. Electrode according to claim 1 to 3 and 6, characterized in that that the electrolyte is an aqueous metal halide and the gas is a halogen. 8. Electrode according to claim 7, characterized in that the electrolyte is a halide of a metal Group HB of the periodic table is. 9. Electrode according to claim 6, characterized in that the gas is chlorine or bromine. 10. Electrode according to claim 6, characterized in that that the holes (40) through a part of the electrode for the passage of undissolved gas in the porous part (25) are arranged. 11. Electrode according to claim 6 and 10, characterized in that that the holes (40) have a diameter between about 0.1 and about 3.0 mm. - 36 - 309821/0797 - ± 56 - 12. Electrode according to claim. 1 and 2, characterized in that that the porous electrode (25) 'is grooved so that when the second part (21) is attached, the Passages (29) are formed for the flow of electrolyte. 13. Bipolar cell of a secondary battery of high Current density, characterized in that it consists of a pair of bipolar electrodes (13, 15) according to claim 1 and 2, the passages (29), a porous body (25) and a gas and electrolyte impermeable Wall (21) composed of a strongly electropositive metal (23) on one side thereof and consists of an organ designed to convey an aqueous electrolyte solution of a halide this ketalIs and the elemental halogen this Halogen! Ds through the passages between the impermeable and the porous parts can exert a pressure sufficient to cause the aqueous electrolyte to drive across the porous body in a reaction zone (31) between the porous body and the impermeable wall coated with a highly electropositive metal is arranged and the hood represents between the electrodes, in which metal and halogen react to form metal halide 309821/0797 and one between the metal and halogen electrodes can generate flowing electrical current. 14. Bipolar cell according to claim 13, characterized in that the impermeable walls (21) are made of graphite, that the highly electrolytic metal (23) is plated on the sides of the walls , that the porous IC body (25) made of amorphous carbon or Graphite and has such a porosity that a cross-section consists of 20 to 80 ° ß> carbon (including graphite) and the pores in, or passages through, the carbon have an average diameter of 5 to 300 microns that the passages (29) extend over almost the entire length of the walls, run vertically, are flat and have width-to-thickness ratios in the range of 2: 1 to 10s-1, that the electrodes are flat, that the organ for conveying the halogen-containing aqueous halide electrolyte solution through the passages and the porous carbon is a pump and that the organ for removing the electrolyte from the passages has a discharge line (19) which is denoted by me its passages is connected. - 38 - 309821/079? ORIGINAL WSPECTED 15ο bipolar cell according to claim. 14, characterized in that that the zinc (23) on the graphite parts of the cell and the parts (25) made of porous carbon the cell are held at a distance by a frame, the frame with the zinc electrodes, the electrodes the cell is made up of porous carbon and the electrolyte. 16. Bipolar cell according to claim 13 to 15, characterized in that that the electrolyte is an aqueous zinc chloride solution containing elemental chlorine and the zinc plating is between 25 and 4000 microns thick. 17 device for storing electrical energy, characterized in that an electrode vessel at least a positive (13) and a negative (15) electrode, the negative electrode being a surface (23) consists of an oxidizable metal which electrochemically combine with a halogen can, and contains an electrolyte in which gaseous halogen is dissolved and which is in electrical Contact is made with the positive and negative electrodes, at least one electrode being the electrode according to claim 1 is. - 39 309821/0797 ORIGINAL INSPECTED 18. The device according to claim 17 »characterized in that the electrodes" are bipolar electrodes and that the other side is impermeable to the gas and / or electrolyte flow _o 19. Gate direction according to claim 17 and 18, characterized in that the electrolyte is an aqueous metal halide and the gas is a halogen _o 20. Gate direction according to claim 17 'and 18, characterized in that that the electrolyte is a halide of a metal of Group II B of the periodic table. ο Device according to claims 17 and 18, characterized in that that the gas is chlorine or 3rom. - 22. Apparatus according to claim 17 and 18, characterized in that the electrolyte is zinc chloride _o 23. The device according to claim 6, 17 and 18, characterized in that the diameter of the holes (40)
between about 0.1 and about 3 mm. 24. Device according to claim 17 "to 23, characterized in that that multiple cells with "bipolar electrodes - 40 309821/0797 ORIGINAL INSPECTED ? ? S R R Λ (13, 15) electrically connected to other devices and with a device π around the corner of the electrolyte from the cells, a device for enriching the aqueous zinc chloride electrolyte with elemental Chlorine after completion of the electrolytic reaction and converting the chlorine to chloride and means for recirculating the enriched one Electrolytes are provided through the cells. 25. A method for generating electrical energy in a device for storing electrical energy Energy, characterized in that an aqueous metallic halide electrolyte, containing dissolved halogen into and through an electrode is passed through and out of this, the electrode vessel having at least one porous positive and contains a negative electrode and wherein the nef'ative Electrode has a surface made of an oxidizable metal, and that the electrolyte and dissolved Gas through the pores of the positive electrode and undissolved gas through the holes in the electrode relieved, whereby electricity is generated. 26. The method according to claim 25, characterized in that the aqueous zinc chloride electrolyte, the dissolved - 41 309821/079 "' ORIGINAL! MSPECTED Contains chlorine across a porous electrode Kohl'3113toff, after ionizing one Partly deο original chlorine enriched with chlorine, with that part of the electrolyte that makes up the. vo ^: .en '> e ± U.ii has flowed through, mixed and returned to the electrode vessel, where "the mixing is carried out either before or after the enrichment. 27. The method according to claim 25 »characterized - ^a e indicates that an electrode, which is impermeable to gas and electrolyte, is connected as a negative electrode. 28. The method according to claim 25 »characterized in that that a halide of a metal from group II B of the periodic table is used as the electrolyte. 29. The method according to claim 25 »characterized in that that rock gas chlorine or bromine are used. 30. The method according to claim 25, characterized in that that zinc chloride is used as the electrolyte. '31. Method according to claim 25 "to 30, characterized in that - 42-309821 /0797 ? ? .S S R 4 draws that the electrolyte at the bottom of the electrode introduced and <i> 3 un -elaste Gaa and the electrolyte ata head of the electrode must be removed. 52. The method according to claim 25 to 10, characterized in that i'ekenn—
shows that dos --aa is passed through holes in the positive porous electrode. 'yj' The method of claim j2, characterized in that the gas through the porous electrode located in holes having a diameter of about 0.1 to about; 3, Ö ^ mn eleitet iärd. 309821/0797 BATH ORIGINAL