DE2338544A1 - ELECTROCHEMICAL ENERGY CELL - Google Patents

Description

The invention relates to an electrochemical energy cell and in particular to an electrochemical cell with high energy and current capacity.

For many purposes it is necessary to set free a very large amount of electrical energy in a short time. Therefore, efforts are being made to develop cells that can deliver a high current output per unit volume and weight. The total energy that an electrochemical primary cell is able to deliver is of course largely dependent on the amount of predetermined electrochemical reactants in the cell. However, different electrochemical cells may be available Release energy within different periods of time. That is true

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even if the same electrochemical conversion is used. The rate at which a cell's energy is released and the total energy available per unit of volume and weight are therefore not just a function the chemical reactants, but also a function of other parameters of the cell, including physical and with the chemical conversions of related parameters. In particular, it has long been known that the physico-chemical structure the electrodes are essential for the activity or the maximum current delivery capacity of an electrochemical Cell is.

The invention relates to electrochemical cells of high energy and current capacity. I.e. it concerns electrochemical cells, which per weight and volume unit a strong current and able to give off great energy. The invention relates to both electrochemical reserve cells in which the electrolyte kept separate from the electrodes until the battery is made ready for use, as well as conventional electrochemical Cells in which the electrolyte is introduced into the electrode structure during manufacture. Though in the cells In principle, any electrode structure can be used according to the invention, a specific electrode structure is used below described for these cells. With this special electrode structure, the cells are capable of each weight and volume unit to emit a very strong current and high energy.

So that electrochemically a high energy or current output can be achieved it is essential to select highly reactive electrochemical reactants, being among the most suitable cells those include the anodes made from magnesium, zinc or aluminum and cathodes made from silver oxide, copper oxide, nickel oxide or mercury dioxide own. However, the electrode structure according to the invention is not directed to a specific pair of electrodes or to one of the above-mentioned electrode materials, but is

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suitable for most, if not all, cell systems Current or. Energy capacity per unit of weight and volume to improve.

One of the main characteristics of the electrode structure according to the invention is the physico-chemical structure of the Cathode. Conventionally, the cathode is a primary cell of an electrically conductive inert support element and a coating made of the cathodically active electrochemical material made on it. It has now been found that the activity of the cathode can be greatly improved if the support element a coating made by sintering together nickel ammonium sulfate is generated on its surface, so that this coating between the support elements and the electrochemical reactive cathode material.

Another essential feature of the electrode structure according to the invention is based on the discovery that the energy capacity of a cell can be improved considerably if the electrodes and especially the anodesi are perforated in this way are designed that their surface is increased per unit volume. To this end, special measures will continue in the manufacture of the interacting elements of the cell taken in such a way that they follow the contour of the Electrode gaps follow and thereby the electrochemical effect of the perforated electrode and the chemical content of the cell to the maximum.

Show in the drawings

Figure 1 shows a first embodiment of a reserve battery according to the invention;

FIG. 2 is a plan view of one of the cathode plates of FIG Battery of Figure 1;

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FIG. 3 shows a section through the cathode plate of FIG. 2;

FIG. 4 is a plan view of an anode disk of the battery of FIG. 1;

FIG. 5 shows a section through the anode disk of FIG. 4;

FIG. 6 shows a cross section through the support for the anode of the battery from FIG. 1;

Figure 7 is an end view of the carrier of Figure 6;

Figure 8 is an end view of the positive terminal end of the battery of Figure 1;

Figure 9 is an end view of the cathode end of the battery of Figure 1;

Figure 10 is a detailed view of the activation plunger and release valve of the battery of Figure 1;

FIG. 11 shows a thin cylindrical reserve battery according to the invention;

Figure 12 is an end view of the battery of Figure 11 from the cathode side;

Figure IJ) is an end view of the battery of Figure 11 from the anode side;

FIG. 14 shows a third embodiment of a reserve battery according to the invention;

Figure 15 is a side view of the battery of Figure 14;

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ORIGINAL INSPECTED

Figure 16 is another side view of the battery of Figure 14;

FIG. 17 is a side view of the battery of FIG. 14 after the battery has been activated;

FIG. 18 is a schematic view of the disassembled parts of part of a battery of cells according to FIG the invention;

Figure 19 is a front view of an electrode structure according to the invention;

Figure 20 is a fragmentary cross-section showing the details of a sub-battery of cells made according to the teachings of the invention are constructed - shows; and

Figure 21 illustrates one effective way of arranging the anode and cathode of a cell in accordance with the invention.

For purposes of illustration, the invention will hereinafter be described for a magnesium / magnesium perchloride, lithium perchloride / vlercurioxid cell or battery. As mentioned above, however, the invention does not apply to such a cell or Battery limited.

Reference is first made to FIGS. 18 to 21. Figure shows the disassembled parts of a part of a battery or cell. According to FIG. 18, this sub-battery has two anodes and one cathode. The anodes 111 are made of magnesium foil, for example a magnesium foil such as that manufactured by Dow Chemical Co. under the ASTM designation AZ-21. or AZ-31, the is preferably about 0.013 cm (0.005 inches) thick. The cathode 112 has a stainless steel sheet 113 about 0.0025 cm (0.001 inches) thick as a support member, both sides of which have

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are covered with a base layer of mercury dioxide. A thin absorbent separator 115 made of fibrous material, for example may be made of paper, lies between each anode and cathode 112 and contains an electrolyte solution.

The anodes 111 and the cathode base element 113 - made of stainless steel Steel are practically the same in their physical structure and are illustrated by FIG. 19 in their front view. Both electrode elements 111 and 112 have stamped Holes 116 on. One has proven to be particularly cheap

approximately

Hole diameter of / 0.16 cm (1/16 inch) and the holes are preferably evenly distributed so that there are about 7.9 holes per cm of surface (about 20 holes per inch of surface area), so that the ratio of hole surface to total surface area is about 0.066: 1. For each electrode element is a connection lug 117 is provided.

According to the invention, the perforated base element made of stainless steel is heated in a hydrogen atmosphere (or another reducing atmosphere) for about 20 minutes to a temperature of about 300 ^° C. in order to remove all oxide from the surface before the application of the mercury dioxide. Nickel carbide is then vacuum sprayed onto this element to form a surface coating between about 0.00076 and 0.0020 cm (about 0.0003 and O.OOO8 inches) thick. Then a thin layer of nickel-ammonium sulfate crystals is placed over the surface of the electrode element 113.

Stroke p so that about 0.15 g of salt per cm of total area (about one gram of salt per square inch of overall area), and the salt is then sintered by placing it heated to about 360 ° C in nitrogen or another inert atmosphere. The processing of the basic element made of stainless Steel, after it has been freed of surface oxide and until sintering has ended, is of course done as much as possible Absence of oxygen.

3E (nickelous ammonia sulfate)

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ORIGINAL INSPECTED

The electrode element Hj5, which is provided with a coating of sintered nickel ammonium sulfate in this way, is ready to receive the mercury oxide paste. This paste is prepared by ■% carboxymethylcellulose mixed Mercurioxid to improve its conductivity with carbon black in a weight ratio of about 9 »5SL as well as a small amount of a suitable binder, such as 0.05 wt. *. This mixture is dry milled in a ball mill for about 1 hour. Then enough water is added that a thick paste is formed, and this paste is ground in the ball mill for a further hour. The resulting mixture is applied as a thin layer approximately 0.08 cm (about 1/52 inch) thick over both surfaces of the electrode element 112 produced as described above.

2 spreads. Approximately 0.23 g paste is required per cm of total electrode surface (about 1-1 / 2 grams per square inch). The electrode thus prepared is in an oven for about J> 0 minutes at about 93 ⁰ C (200 ° fahrenheit) dried.

In the manufacture of an electrode such as the electrode 112 shown in FIG. 1, the base element 113 is made of stainless steel The steel is coated on both sides and the paste penetrates the punched holes 116. Through this there is a connection between the paste and the base element, so that the assembled electrode system is mechanical is solidified.

In Figure 20 is an enlarged fraction of a cross section of cells connected in series. To from the surface enlargement produced by the punchings in the anodes 111 To take advantage, the separators 115 are adapted to the holes and follow the spaces thus formed, so that a maximum of electrode anode boundary surface arises. The surfaces of the cathodic mercuric oxide layers also follow the contour of the perforated anode, so that the content of the cells of chemical reactants is a maximum. This we-

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kung can be achieved by removing the surfaces of the layers of the mercuric oxide paste when the cathodes are formed, shapes by embossing with a stencil before the paste is dried. Then anodes and cathodes with between them embedded fibrous separators 115 joined together, the fiber layers adapting to the contour of the cathode surface and take the form shown in FIG. If so desired Of course, fibrous electrolyte carriers or separators 115 can be sprayed directly onto the anodes 111 or made of paper stock be shaped.

The battery illustrated in Figure 20, which is a conventional battery in which the electrolyte is used during manufacture of the Battery is introduced, is so by the usual superimposing of flat anode and cathode plates with embedded Separators manufactured. An alternative very effective form of cell structure is illustrated in FIG. A first electrode strip 121 is sinusoidally deformed into a number of contiguous, superimposed sheets, while the other electrode strip 122 is guided in the same way sinusoidally orthogonally to the first strip. the Lugs 123 and 124 provide the connections for both electrodes represents. One of these electrode strips represents the anode and ε ^ φ rricht completely the anodes 111 described above, while the other electrode strip represents the cathode and corresponds completely to the cathodes 112 described above. The separator or separators between the opposing parts of the two electrode strips 121 and 122 is not shown so that the drawing is clearer. The required function can of course be achieved by separator strips, attached to both sides of one of the electrode strips. Alternatively, the separator layers can be produced on a strip by spraying or by deforming paper stock. It is best to shape the cell of Figure 21 before applying a Mereurite oxide coating

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has dried on the cathode and while it is still in a plastic state. After the cell is formed and pressed so that all the adjacent surfaces in contact with each other and are physically matched each other, the unit to a temperature of about 93 ⁰ C (200 Fahrenheit) heated to dry it.

The electrolyte that is formed along with those as described above Electrodes can be used is a 5.n aqueous perchlorate solution of magnesium and lithium in weight ratio 95: 5. In the battery shown in FIG. 20 and in the electrode arrangement illustrated by FIG. 18, the electrolyte incorporated into fibrous carriers or separators 115 during assembly of the battery. The storage stability however, a battery with the active materials described above is quite limited. Therefore, for most purposes the cells or batteries with the electrode structures according to FIG Invention designed as reserve cells or batteries. In such batteries there is a inside the battery housing its own electrolyte container, and means are provided to break the container when the battery is in use shall be. If the container is broken, the electrolyte will spread itself in the separator made of fiber material and the porous anode.

Reserve batteries or cells in which an electrode structure can be used in accordance with the invention are illustrated by Figures 1-17. Figures 1 to 10 show a cylindrical molded reserve battery. The battery is in a metal container 1, at one end of which is an insulating plastic disc 2, which carries the anode terminal j5, is included. The anode has an anode shaft 6 to which the disk-shaped anodes 4 are welded at the connection points 5. The cathodes 7 are welded to the cylindrical metal housing 1. When assembling the battery, the cathodes 7

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and the anodes 4 alternatively in the container of the battery with a tool intended for this purpose, which makes it possible to To connect anodes and cathodes by laser welding with the specified surfaces, introduced. I.e. the disc-shaped Anodes are welded to the anode shaft 6 and the cathodes 7 are welded to the container 1. That way will the container or housing 1 becomes the cathode of the battery and the cylindrical shaft 6 becomes the anode,

The electrolyte 13 is held in the container 10 until the point in time at which the battery is to be activated. Of the Container 10 can be made of glass, plastic, or other suitable fragile material. When the container 10 is broken, the electrolyte IJ flows down into the Electrode structure. To allow the electrolyte 13 to flow into the To facilitate the electrode structure, the shaft 6 has a central bore 9 and is provided with a number of holes 8. Four rows of holes or perforations 8 are provided along the length of the shaft 6.

The cathode disks 7 are also constructed in such a way that they do the distribution of the electrolyte 13 facilitate. FIG. 2 shows a plan view of a cathode disk 7. As shown in this figure As can be seen, a cathode disk 7 has slots 12. When the cathode disks are placed in a battery container 1 are, an opening is formed through these slots 12 between the container 1 and the cathode disks, so that electrolyte can flow down between the inside of the container and the cathode disks. Figure 3 merely illustrates a cross section through the 'cathode disk of Figure 2. The porous separators 115 shown in FIGS. 18 and 20 are not shown in FIG. If in the battery of figure the electrode structure of FIGS. 18 to 20 or the electrode structure of FIG. 21 are used, porous separators are also used, as shown in these figures. Of the

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Electrolyte would then be absorbed by the porous separators.

Figure 8 is an end view of the anode terminal of the battery of Figure 1. As shown in Figure 1, this is the bottom of the battery Battery. Figure 8 shows that the anode connection 3 against the battery housing or the container 1 by an insulating Washer 2 is isolated. This figure also shows that the battery is cylindrical.

The device for breaking the frangible container is shown in FIGS. 1, 9 and 10. As shown in these figures, the fragile envelope is broken 10 a spring loaded plunger 16 is used. To prevent unintentional lowering of the plunger 16, there is a stop 18 provided. The stop 18 is removed by pulling it away from under the plunger 16 and the plunger 16 then becomes depressed to break the envelope 10. When the envelope 10 breaks, electrolyte 13 flows as described above into the electrode structure. When energy is drawn from the battery, gases are generated within the battery. Included the gas pressure could become so high that the battery is damaged. Therefore, in the plunger 16, a drain port 17 * is through which the gases can escape is provided. Normally, the opening 17 is made by the action of the spring of the spring-loaded Plungers 16 closed. When the pressure in the battery container 1 increases so far that the spring of the plunger is pulled apart, the gas flows through the hole 17 through the plunger 16 into the ambient air, in which it opens the valve 19 raises.

Figures 11 to IJ show a second reserve cell or battery according to the invention in which the electrode structure according to the invention can be used. As in these figures shown, this second embodiment also has a cylindrical shape, each

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but the shape of a thin cylinder. Given the diameter of this cylinder, the battery is very thin. Of the Structure of the battery shown in Figures 11 to 13 is very similar to that of the battery shown in FIGS. 1 to 10, with the difference, however, that the electrolyte 38 is stored in a container 31 placed in the middle of the battery. At one end of the short metallic container 32 a plastic disk 33 is attached. The plastic disk 33 isolates the anode connector 34 from the metal container 32. The other end of the metal container 32 holds a flexible plastic disk 35. The anode disk 40 and the cathode disk 41 are essentially the same as the anodes and cathodes of the battery shown in FIGS.

Figure 13 shows the anode terminal end of the battery of Figure 11, and Figure 12 shows the other end of the battery of Figure 11. The Figures 11 and 12 show the activation mechanism of this battery. This activation mechanism is the same as the activation mechanism of the battery of FIGS. 1 to 10. Here, too, a plunger 36 acted upon by a spring 44 is provided. Unintentional activation of the battery is prevented by a stop 37. To activate the battery, the stop 37 is pulled away from under the plunger 36, and the plunger 36 is lowered to enclose the fragile envelope 31 breaks. If the frangible envelope 31 is broken, the electrolyte can enter the space 39 between the Electrodes flow and thus activate the battery. A drain hole 42 is provided to allow the escape of gases generated in the battery. A "valve 43 holds the hole 42 normally closed. When the pressure rises sufficiently, the valve 43 opens and enables the The gases escape from the interior. As in the case of the battery shown in FIGS. 1 to 10, the batteries in FIG. 11 are also porous Separators 115 not shown. However, if the above-described electrode structure in the battery or cells like them

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are illustrated in Figures 11 to 13, can be used, Porous separators 115 must also be used in these batteries.

Figures 14-17 illustrate a third reserve battery or cell according to the invention. The battery or cells shown in FIGS. 18 to 20 can also be used in this battery or cells illustrated electrode structure or the electrode structure of Figure 21 can be used.

As shown in Figures 14 to 17, this battery or cell is designed as a flat, right-angled pack. The battery has a flexible plastic housing 50 which contains the electrodes 51. The terminals 52 are leads outwardly overall ■, lh as shown in FIGS to I7 shown. The electrolyte is contained in a thin, fragile envelope of glass or any other suitable material. The metal plates 56 are so connected to a joint 55 in that they can be separated from each other and folded over plastic plates 50, as indicated by the Figures 15> 16 and 17 illustrated.

When the metal plates 50 are folded around the plastic container 50 and are pressed against it, they break the fragile container 53 and force the electrolyte into the space 57 between the electrodes, which in turn can contain the separators 115 shown in FIGS. When the electrolyte is pressed into the space 57 between the electrodes, the battery or cell is activated. The plates 56 can then of the joint 55 can be released or, if desired, held in the position shown in FIG. However, if the metal plates 56, since the battery is relatively flexible, it can be bent into a number of desired configurations will.

In the three reserve batteries shown in FIGS

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any conventional electrodes and chemicals can of course be used. However, these batteries are supposed to or cells have a high energy and current capacity. Therefore, in these batteries or cells, the Electrode structure and chemicals as described above with reference to Figures 18 to 20 and 21, used. The two illustrated in Figures 1 to 13 Batteries are cylindrical batteries. Therefore, the basic element shown in Figure 19 should be circular with a concentric one central hole so that the electrodes the anode post of the two illustrated in Figures 1-13 Batteries or cells can be watched. In all other respects, however, the cathodes and anodes would have to be manufactured, as described with reference to FIGS. I.e. the basic elements of the electrodes would be perforated elements, and the cathode would contain the sintered nickelo-ammonium sulfate between the base element and the cathode active material. In addition, separators 115 would be placed between each anode and cathode disks. If, on the other hand, the in Figure 1 illustrated embodiment with interlocking strips were used, the anodes and cathodes could be formed to fit the contours of the cylindrical battery case are closely matched.

In the case of the reserve battery or cell shown in FIG For example, the electrode structure shown in Figs. 18 to 20 and 21 can be used as it is because this battery or cell is generally rectangular. In the case of reserve cells or batteries, the electrolyte solution is removed from the porous ones Separators 115 absorb when the frangible envelope is broken, activating the battery. Because of the cavities or holes 116 in the electrodes, there is a complete electrolytic equalization of the potential between all cells of a battery. This naturally increases the output efficiency of a battery.

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As mentioned above, the batteries or cells according to the invention have a high energy and current capacity. For example the energy capacity and activity of cells or batteries according to the invention is illustrated by that a single battery with the electrodes and electrolytes described above with a total volume of 16.4 cm (one cubic inch) can provide an output of 5 amps at 1.5 volts for 60 minutes.

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Claims (16)

:,: July 30, 1973 P ate η claims Electrochemical primary energy cell, thereby marked that they a) an anode; and b) a cathode with a support element, an electrochemically active cathode material and a through Sintering of nickelo-ammonium sulfate formed coating between the support element and the active cathode material having. 2. Electrochemical cell according to claim 1, characterized in that it is an electrolyte contains. 2. Electrochemical cell according to claim 1, characterized characterized in that the support element is made of stainless steel and is practically free of surface oxides is. 4. Electrochemical cell according to claim 3, characterized characterized in that the support member has a coating of nickel carbide between its surface and which has a coating of sintered nickelo-ammonium sulphate. 5. Electrochemical cell according to claim 4, characterized in that the anode is perforated is that a porous separator lies over the perforated anode and the surface contour of the perforations is adapted in the perforated anode and that the cathode covers the porous separator and also the - 16 -509811/0412 Surface contour of the perforations in the perforated anode is adapted. 6. Electrochemical cell according to claim 5> characterized in that both anode and Cathode consists of a strip that is sinusoidally bent around itself, so that a number is contiguous to one another opposite leaves are formed and a folded one Strip is arranged transversely to the other and its sheets are between those of the other strip is formed are. 7. Electrochemical cell according to claim 6, characterized characterized in that the arrangement is practically orthogonal transversely to one another. 8. Electrochemical cell according to one of claims 5 * 6 or 7, characterized in that the cell is a reserve energy cell, the electrolyte of which is stored in a fragile envelope. 9. Electrochemical cell according to claim 8, characterized in that the reserve cell is cylindrical and has means for breaking the frangible envelope. 10. Electrochemical cell according to claim 9, characterized in that the means for breaking the fragile envelope of a spring loaded plunger 1st. 11. Electrochemical cell according to claim 10, characterized characterized in that a number of them are combined to form a battery. - 17 509811/0412 12. Electrochemical cell according to claim 8, since d u r c h characterized in that the reserve cell as is formed in a flat rectangular package and has means for breaking the frangible envelope. 1J>. An electrochemical cell according to claim 12, characterized in that the means for rupturing the frangible envelope consists of a pair of hinged plates attached to the cell. 14. Electrochemical cell according to claim 1J>, characterized in that several of them are combined to form a battery, such that all cells are contained in a single container. 15. Electrochemical cell according to one of claims 1, 10 or 15, dadur.ch characterized in that the Cathode is made by removing practically all oxides from the support element, the practically oxide-free support element is then coated with nickel carbide, the support element coated with nickel carbide with nickelo-ammonium sulfate is coated and the sulfate is then sintered in an inert atmosphere. 16. Electrochemical cell according to claim 15 * thereby characterized in that the cathodically active paste is applied as a coating to the sintered surface is. - 18 - 509 * 311/0412 -49- Blank page