DE1496116A1 - battery - Google Patents

Description

Patent attorneys

■ ötpl.lnq.F.Weickmann, Dr. Ing.A. Wefckmann i ^ ftVift

B Munich 27, MöhistraOa 22

battery

The invention relates to a battery, in particular an improved collector or accumulator.

A major class of common collectors uses lead-lead dioxide as an electrochemical pairing and is commonly called lead-acid collectors (Lead accumulator). Such collectors have found widespread use, especially as a starter battery for Motor vehicles. But they are not particularly cheap as sources of motive power, for pulling purposes, for example, where space and weight have to be limited. Lead-acid batteries have a low Energy density, i.e. output power per unit of battery weight. A conventional lead accumulator theoretically has a maximum energy dissipation of 76 watt hours per pound (454 g) of the reactants and in practice generates 5 to 20 att hours per Pounds "of total battery weight. The low energy yield per unit weight comes primarily from the high molecular weight of the plate material and the rather large excess of anodic and cathodic reactants that are necessary because not all of the electrodes can be broken down while the battery is discharging. The reversibility of the lead accumulator depends on the physical position of the reactants and the conversion products and makes the use of highly porous metal electrode plates is necessary in order to

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solid-pesticide reactions find a sufficient surface to offer..

The main aim of the invention is a collector with a high energy density. Furthermore, this collector should be easy and convenient to charge. Furthermore, the invention aims to create a collector, which is convenient to use and economical to manufacture, and which is trouble-free during discharge and recharge is working.

These and other features and advantages of the invention will become apparent from the following detailed description with reference to the accompanying drawings Drawings. Show it;

Figo1 is a perspective view with exploded Ropes that are a specific embodiment of a cell for one Collector shows;

FIG. 2 shows an enlarged partial section of the cell from FIG

3 is a schematic drawing of the flow of one of several Single cells according to Fig. 1 and 2 assembled battery.

In the drawings, a cell 10 is generally shown, which is formed according to the teaching of the invention and comprises an anode 12 made of zinc and a cathode 14 which is spaced from the anode and of oxygen dureli- ^; - ■ is flowing. An aqueous solution of a caustic electrolyte circulates between the anode 12 and the cathode 14.

The electrochemical zinc-oxygen pairing formed in this way has a high theoretical capacity and a high utilization factor for the aiiodic and cathodic reactants. ^L zinc is the lightest ^; irochelectröpositive solid element, which is in

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an aqueous solution in the undiluted state in plate form can be. Oxygen is light in weight and available from the atmosphere, which makes it among the possible gaseous Gives respondents a unique position as it does not require a heavy and space-consuming storage device. The theoretical reaction potential

Zn + 1/2 O ₂ ZnO

is 1.65 YoIt and 1.4 volts are as open terminal voltage actually available.

For the sake of clarity, the various components in the Pig. 1 and 2 are listed and explained from left to right. The battery 10 includes a practically rectangular anode back plate 16 to which the zinc anode 12 is attached, for example by means of electrolytic deposition. The anode back plate 16 is made of an electrical conductor that is insensitive to the caustic electrolyte, for example nickel. The back plate 16 contains channels 18 and 20 in the lower left and » upper right corner, which form a passage for an aqueous solution of a caustic electrolyte, such as potassium hydroxide solution, through the cell, as will be explained in more detail below. In the channels for the electrolyte, sealing rings 64 made of an insulating material, such as plastic, are provided, which are intended to prevent the electrolytic corrosion of the cathode plates, which could otherwise occur with short-circuited cells connected in series. In the lower right respectively. In the upper left corner, channels 22 and 24 are provided for the passage of an oxygen-containing gas, for example air, as will be described in more detail below.

The zinc anode 12 is from the oxygen cathode 14 by a

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practically rectangular, porous, inert septum 26 separated the for example made of porous plastic or other porous, non-conductive There is material that is not attacked by the caustic electrolyte, and the surfaces 28 are corrugated on both sides are. The grooved surfaces 28 lie on the anode backplate 16 opposite to allow the greatest possible zinc deposition on the surface of the back plate 16, and opposite the oxygen cathode H to get a free entry of the oxygenated Allow grass into the electrolyte.

As shown in 3? Ig.1, the heather wall is through a Line insert 30 made of a non-conductive material that is insensitive to the caustic electrolyte, such as polyethylene, ■ Polypropylene, phenol, etc., framed. The upper and lower horizontal branches of the insert 30 are .mit horizontally running Slits 32 and 34 are provided which serve as a manifold for a plurality of vertical drainage grooves 36 and 38 which extend between the slots 32 and 34 and the grooves in the surfaces of the septum 26 extend.

Between the line insert 30 and the rear plate 16 is located

sr

a sealing frame 40, which covers the slots 32 and 34 and the extraction grooves and thereby prevents the electrolyte from seeping out. The wire frame 40 is made of any suitable non-conductive material, for example plastic, such as polyethylene, polypropylene, phenols, etc., or of other materials which are not attacked by the caustic electrolyte.

In the illustrated embodiment, the J is the sealing frame 40 provided in its corners with channels 18, 20, 22 and 24, which together with the channels 18, 20, 22 and 24 in the anode back

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Plate 16 allow the electrolyte and the oxygen-containing gas to pass through the sealing frame. The ends of the slots 32 and 34 in the line insert 30 are located in areas which are connected to the channels for the electrolyte in the sealing frame, and thus enable the electrolyte to pass through . Slots 32 and 34 or in the same. The channels 22 and 24 in the lower right respectively. The upper left corner of the sealing frame is used for the passage of air.

As can be seen from FIGS. 1 and 2, the cathode 14 is on the right arranged by the insert 30? it comprises a porous component 44 with a middle piece 52, which consists of an electrical conductor that cannot be attacked by the electrolyte, such as mckel powder. That The component is made sufficiently porous to allow the oxygen-containing gas to diffuse through; preferably is for the cathode a finely powdered material is used to obtain a surface that is required for maximum output power. In particular if air is used as the oxygen-containing gas, should allowing air to pass through the porous cathode and bubble into the electrolyte.

The porous member 44 is provided with a fixed R _a hmen 50 provided in one piece, which consists of an insensitive to the electrolyte and electrically conductive material such as nickel. The fixed frame 50 serves as one side of the manifold in the insert 46. In the corners of the frame 50 are channels 18, 20, 22 and 24 which, together with the channels in the other cables, allow the passage of gas and electrolyte. The frame 50 also acts as a cover for the slots 54 and 56 and the extraction grooves 58 and 60 and prevents them from escaping

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of gas from these.

To the right of the cathode 44 is a cable insert 46 for the Arranged gas, which is formed substantially the same as the Insert 30 and made of a similar non-conductive material. Similarly, the insert 46 is horizontal Slits 54 and 56 are provided in its upper and lower branches, the connected by a plurality of vertical drainage grooves 58 and 60 to the interior of the space defined by the insert are. A filler made of a porous, electrically conductive material, for example of stainless steel chips or synthetic fibers with a nickel coating. Of the The insert rests firmly against the fixed frame and the frame serves to cover one side of the branch lines and drainage grooves.

In i * ig.1 channels 18 and 20 are respectively in the lower left. upper shown right corner of the line insert 46, which together with the channels 18 and 20 already described above, a Durciw occurs for the electrolyte to form in the cell. The slots in the insert extend into areas with the gas channels 22 and 24 are connected and take up gas from these.

A back plate 62 made of inert, electrically conductive material, such as nickel, is arranged to the right of the line insert 46 for the gas. The backplate can serve as an anode backplate for a subsequent cell (not shown) in a series arrangement of cells. The back plate 62 is equipped with channels 18, 20, 22 and 24 in the corresponding corners which allow the electrolyte and the air to pass into the subsequent cell and which are connected to the channels 18, 20j -22 ^;

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and 24 work together. TJm zu'verhappen that the electrolyte Cell 10 and in particular cells connected in series short-circuits ", the electrolyte channels 18 and 20 in the back plate 62 are equipped with inert, non-conductive sealing rings 64.

A battery 65 is shown in FIG. 3, which has a plurality of individual cells 10 according to 3? Ig.1 are used, which are held together by suitable components (not shown), for example by a plate and pressure frame are. Any number of individual cells can be used in the battery 65 10 can be used, which can be combined in different parallel and series circuits, depending on the desired Output power of the battery. It is for a series connection the desired number of cells in the air gap a non-conductive Filler is provided and the cathode frame and the back plate on both sides of the air space are made extra thick »On this one The cathode and this back plate are attached for the electrical connections (not shown) tabs. The neighboring groups of cells connected in series are connected in parallel

The arrangement of a number of cells connected in series with a common electrolyte leads to self-discharge currents between cells. In the example of Pig.1 these currents are ' kept within tolerable limits by making the electrolyte channels narrow and the number of in a single series circuit pooled cells are limited.

An oxygen-containing gas, such as air, is introduced into the battery 65 by means of a gas blower 66 and a gas line 68, through the gas channels 22 and the cathodes 14 of the individual cells 10 deletes. An electrolyte is supplied to the electrolyte channels 18 of the cells 10 in the battery 65 through the line 70. The electric

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lyt is withdrawn from the battery 65 via the line 74 and runs through a heat exchanger 76 into a storage tank 78 for " the electrolyte, where it is further cooled. From the storage tank 78, the electrolyte passes through a line 80 to the inlet of the pump 72 “The pump 72 pumps the electrolyte in a line 70 through the heat exchanger 76, which is in heat exchange with the line 74 stands; in this way a closed circuit is provided for the electrolyte.

In order to achieve the desired high energy densities, the zinc oxide reaction products generated during the discharge of the battery are used preferably removed from inside the cell. If the reaction products are not removed from the cell, or not be at least brought into circulation to prevent a deposit on the anode surface, it will .re required a large To use the amount of electrolyte to completely dissolve the zinc oxide breakdown products formed; however, the energy density is thereby per unit of the total battery weight greatly reduced. However, if the electrolyte circulates through the battery, the reaction products formed from the vicinity of the anode surface can be removed and the battery can be operated with a smaller amount of the saturated electrolyte. Of the Electrolyte dissolves the zinc oxide reaction products formed in the battery cell and takes them out of the cell, where they can then be precipitated from the electrolyte solution.

In operation, the caustic electrolyte enters each battery cell enters at the lower left corner through channel 18 and exits the battery at the upper right corner through channel 20, while the oxygen-containing gas is the battery at the bottom

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right corner enters through channel 22 and the cell at the top left corner through channel 24. After its entry, the electrolyte flows through the channel 18 into the slot 32 of the insert 30 and through the extraction grooves 36 into the space defined by the insert. Then he leaves this space through the trigger grooves 38, entering the slot 34 is raid out of the cell through the channel 20 derived.

In a similar way, the oxygen-containing gas flows through the Eanal 22 in the back plate 62 enters the battery cell, gets into the slot 54 in the insert 46 and through the extraction grooves 58 into the space formed by the insert. Part of that in these Interstitial gas passes through the porous surface 52 and thus forms an electrolytic cell between the face 52 and the zinc anode 12. The remaining gas that does not pass through the porous surface 52 flows, flows through the drainage grooves 56 into the Slot 60 and exits the battery cell at the upper left corner through channel 24 Gas that is released during operation of the electrolytic Cell has not been used up, leaves the battery together with the electrolyte through the electrolyte channel 20 identified above.

The aqueous caustic electrolyte, which is heated on its way through the battery, dissolves the zinc oxide degradation products in the Battery on and flows out of the battery through the line? 4 into the heat exchanger, where it meets the electrolyte in the line is in heat transferring connection; eventually it enters the storage tank 78, which is kept at room temperature. By doing Heat exchanger 76 and the storage tank is the the dissolved degradation products containing electrolyte cooled, the zinc oxide

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Reaction products are precipitated in the storage tank 78 «To the To enhance precipitation of the zinc oxide reaction products in the storage tank 78, the tank is filled with a pulp (not shown), such as aluminum silicate fibers, filled, which is responsible for the precipitation of the Zinc oxide offers a large surface. The cooled electrolyte is withdrawn from the storage tank 78 and returned to the battery, where further degraded zinc oxide is dissolved and withdrawn from the battery.

During the operation of the Batceriej, especially when the temperature is high above room temperature, water will evaporate. To refill the evaporated water, the storage tank can be in a suitable Way connected to a (not shown) water refill line be. The battery is preferably dimensioned such that the refilling of water only at the booth every charge-discharge cycle is required. In addition, the storage tank is also equipped with a suitable outlet for the air that is released from the electrolyte was taken along on its way through the cells »

When the battery is recharged, zinc becomes on the back plate Electrolytically deposited by applying a Q voltage to the cells is applied, the current densities up to a few hundred milliamperes

ο
per cm through the cells.

When the battery is being charged, the zinc can also be electrolytically deposited by an alternating current superimposed on a direct current will. The waveform of the alternating current is such, that during a half period of the alternating current a small one Reverse current flows through the battery. The zinc deposited in this way has a moderately coarse crystal structure, but is relative tight and adheres better to the back plate than that

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electricity separated. Because of this, the battery charge -preferable by means of alternating current if large capacities are desired

Most of the time, however, regardless of the specific charging technology used, both during charging and during As the battery discharges, some of the anodic zinc metal is secreted from the anode. The split off zinc metal particles are only sparingly soluble in the circulating caustic electrolyte and will be passed through the system as a suspension in the electrolyte guided; this will reduce the capacity of the battery g In order to avoid the occurrence of anodic zinc metal particles in the circulating electrolyte, in the electrolyte line Means for solubilizing the segregated anodic metal particles to be ordered.

As can be seen from Figure 5, the special means comprise the electrically conductive filter or shut-off member 82, which has a outer electrical lead 84 is electrically connected to a cathode in the vicinity of the outlet lead 74 of the battery 65. That Filter is made of metal, which is from the caustic electrolyte

ι is not attacked, for example made of nickel, platinum, etc. The filter has the shape of a perforated sieve of the order of 50 mesh or a coarse metal fiber plug can be used. The electrolyte circulating through the electrolyte line 74 establishes an electrolytic path between the cathode of the battery 64 and the electrically conductive filter 82; this creates an electrolytic cell between the cathode of the battery cell and any metallic zinc particles that are in contact with the filter. The cell thus formed is through the external electrical

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Conductor 84 short-circuited, as a result of which the split off zinc is anodically dissolved on the surface of the electrically conductive filter. The current flowing in the cell thus formed is passed through an in The variable resistor 86 introduced into the external electrical conduction path is controlled.

The filter is preferably inserted in the electrolyte line at a point where the least effort is made for the dissolved zinc oxide breakdown products exists to deposit on the filter surface. For this reason the filter is advantageous next to the outlet for the electrolyte from the battery cell attached · Although this puts the filter in the line at the point of the highest zinc oxide concentration is in the electrolyte, the temperature of the electrolyte in the vicinity of the outlet from the battery is at highest and the zinc oxide has a greater solubility in this area in the electrolyte, which results in less precipitation of zinc oxide particles on the filter surface. In addition, while the battery is being charged, the flow exiting the battery has the lowest zinc oxide concentration and therefore dissolves any zinc oxide deposits deposited on the filter during the discharge period. But the filter can also be arranged at other points of the circulation system, for example at the outlet of the storage tank, provided that both an external electrical line and a path for the electrolyte are connected to a cathode of the battery.

example

A collector battery is made up of 200 single zinc-acid fuel cells. Each individual zinc-oxygen cell measures 12 inches by 12 inches (-50 χ 30 em) and is 0.01 inch (0.25 mm) thick

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H96116

Nickel anode back plate with the $ 90 diene zinc anode being electrodeposited to a thickness of 0.03 inches (0.76 mm); This is followed by a 0.06 inch (1.5 mm) thick electrolyte lead insert made of polyethylene, a 0.02 inch (0.51 mm) thick, porous nickel cathode, a 0.03 inch (0.76 mm) thick polyethylene air duct insert and 0.01 inch (0.25 mm) thick uickel septum so that each cell is 0.12 inch (3 mm) thick Electrolyte line insert in the way of the electrical. lytes arranged so that the grooved surfaces face the anode and cathode. An electrically conductive laser filler made of iTickel-impregnated plastic fibers is introduced into the space defined by the air line insert. In every twentieth individual cell, the filler is electrically insulating and the cathode and anode are extra thick with protruding tabs for electrical connections. The cells are then arranged in parallel in 10 groups of 20 individual cells each. The cells are put together in a pressure plate frame and the lines in each individual cell for the passage of the electrolyte and the air through the cells are suitably connected to a circulation pump for the Electrolytes and an air blower connected * A 20 percent strength by weight solution of potassium hydroxide solution is pumped continuously through the battery by means of the electrolyte pump at a speed of 0.012 ft / sec (341 cm / sec) i

First of all, the battery is provided with a completely covered zinc anode surface on the anode back plate The blower delivers air at a pressure of 10 psi (0.70 kg / cm) to ■ · Oxygen cathode sent. The temperature in the battery is

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during the discharge of the battery about -70 C and the storage tank is kept at room temperature, ie approximately 30 ⁰ C to 40 ⁰ O, held.

While the battery is discharging, the voltage is everyone

2nd cell without load 1.4 volts; the voltage at 25 milliamps / cm

is 1.2 YoIt and the voltage at 100 milliamps / cm is 1 volt. The cell is preferably not discharged beyond the point where $ 90 of the zinc anode has broken down to zinc oxide. plus $ 90 of the zinc are broken down, the electrical values of the cell structure decrease.

The battery is charged by an external direct current

2 ^: source is connected, which sends a current of 25 milliamps / cm through the cells while the electrolyte flows through the cells. An alternating current is superimposed on the direct current to reverse the sighting of the current in the battery during a portion of the alternating current period. The battery is charged until $ 90 density zinc has deposited 0.03 inch (0.76 mm) thick on the surface of the anode backplate.

The battery supplies 75 kilowatt hours of electrical energy per charging cycle with a nominal output of 15 kilowatts. The battery has an energy density of 90 watt hours per pound and maintains this energy density even after repeated charging and discharging.

In addition to those specifically described, there are other means of directing the electrolyte and air through the battery cell are contemplated, and it is therefore not intended that the invention be limited to the particular ones described. You can of course other methods of removing the zinc oxide from the electrolyte outside the battery are used, for example a filter, that is periodically scraped off; no attempt should be made here

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enumerate all the possibilities for removing the zinc oxide.

It is also possible to cool down instead of the heat exchanger of the electrolyte to use an external cooling device. Further, the battery may be constructed in a shape other than that given as an example, such as a cylinder shape. Also can the arrangement of the adjacent cells can be modified, for example in such a way that each gas channel the oxygen-containing gas to two Conducts cathodes that make up its walls and each anode backplate has zinc deposited on both sides.

In the above, a zinc-acid battery with high Energy density described. The battery is particularly suitable for use as a drive energy source for pulling purposes and also for other purposes where space and weight restrictions apply prohibit conventional collectors. In addition, the battery is easy to use, trouble-free in operation and rarely needs to be charged will.

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Claims (11)

Claims Battery, characterized by a zinc anode (12), a porous, inert oxygen cathode (14) »a conduction path for the electrolyte between the anode and the cathode, means (72) for conducting of the electrolyte through the electrolyte conduction path and means (66) for supplying an oxygen-containing gas to the cathode. 2. Battery according to claim 1, characterized by a conduction path (22,24,54,58,60,56) for the gas on the one facing away from the anode (12) Side of the cathode (Η). 3. Battery according to claim 1 or 2, characterized in that the Electrolyte conduction path through an insert (30) between the anode and the cathode is formed, the branch lines (32,34) for accessories Discharge of the electrolyte to the respectively. contains from the conduction path. 4. Battery according to one of Claims 2 and 3, characterized in that that the conduction path for the gas, preferably air, is formed by a further insert (46) between the cathode and an impermeable plate (62) and branch lines (54,56) for the supply and discharge of the oxygen-containing gas to the respectively. having out of the conduction path. 5. Battery according to claim 4, characterized by channels (18.20 * 22.24) in the anode, the cathode of the impermeable plate (62) and the inserts (30,46), which supply and discharge the electrolyte respectively from the branch lines (32,34) in the electrolyte insert (30) 809902/0056 and the oxygen-containing gas to bezw. from the branch lines (54 »56) in the glass insert (46). 6. Battery according to one of claims 2 "to 5» characterized in that that in the lead electrolyte pathway a porous partition wall (26) and in the grass line pathway an electrically conductive fibrous filling compound (48) is arranged. 7 * battery according to one of claims 1 to 6, characterized in that that the porous oxygen cathode (52) consists of nickel and the electrolyte is an aqueous caustic solution. 8. Battery according to one of claims 1 to 7, characterized by Means for separating the zinc oxide from the electrolyte. 9. Battery according to claim 8, characterized in that the means to separate the zinc oxide from the electrolyte, a device for heating the electrolyte before it passes through include the battery to increase the solubility of the zinc oxide in it, as well as means for cooling the electrolyte after its Passes through the battery to reduce the solubility of the zinc oxide in it and precipitate the zinc oxide. 10. Battery according to one of claims 1 to 9 »characterized by an electrolyte storage tank (78) and a heat exchanger (76), which are switched into the electrolyte conduction path in such a way that the Ee ^ Lktrolyte before entering the storage tank with which the .Storage tank leaving electrolyte in the heat exchanger is in heat exchange. 809902/0056 11. Battery according to one of claims 1 to 10, characterized by one contained in the electrolyte conduction path outside the battery tetes electrically conductive! filter (82) and an electrical line (84) that connects the filter to the cathode. 12, battery assembly, characterized by a plurality of individual cells corresponding to the batteries according to one or more of claims 1 to 10, which are connected in series. 809902/0056