FI81462C - Improved alkaline plate battery design - Google Patents

Description

81 462

IMPROVED STRUCTURE OF ITS ALKALI DISK BATTERY

The present invention relates to an early disk battery whose cells are vacuum-packed in a plastic foil acting as a cell shell. Such cells can be connected in series to an arbitrary number of batteries with the desired voltage. The contact between the cells is provided by a meta-11pi to 11 attached to the positive current collectors 1 of the cells, which, when the battery is assembled, penetrate the negative side of the cells through a tough and adhesive insulating layer and the a mixture of sodium hydroxide solution and gel substance.

Finnish patent No. 65688 describes the original structure of such a battery. Suggestions for improvement have since been made in U.S. Pat. in patents A, 505,996, A, 525, A39 and A, 55A, 226. There is one fundamental flaw in all these solutions presented so far that has caused a lot of inconvenience in factory-made production. The plastic shell of the cell, which is a polyamide-polyethylene laminate, is quite a flexible and tough material. The permeation of the contact is also resisted by an adhesive and tough insulation layer, which in the permeation phase adheres around the peak in a thin sheath-like layer which may insulatively cover a considerable part of the contact peak surface, reducing battery power at high currents. Although the contact spike is sharpened, pushing it through these layers requires considerable force. Therefore, before the final permeation, the soft jelly-like zinc mass beneath these layers gives up. A pit is formed in it, and the zinc paste protrudes radially outward from the penetration point. The shell foil insulation material of the cell bends accordingly, and at the time of penetration outside the cell, radial grooved recesses are formed around the contact peak. Once the cells are finally compressed, these grooves remain as air ducts outward from the contact spike, and such a duct may even extend to the outside air if the sealant layer is uneven or if the compression of the cells does not take place completely perpendicularly. The result may be a detectable leakage of electrolyte from the cell after some time, when the electrolyte has first been able to penetrate the above-mentioned air ducts along the contact, e.g. In the finished battery, the cells are subjected to a compressive pressure, which can gradually cause the alkaline electrolyte of the surfactant to find its way along said grooves between the lid foil of the adjacent cell and the sealant layer out of the battery. Such a phenomenon has been found to occur within a few hours at the temperature of + 71 ° C required by international quality tests.

The three U.S. in the case of the patent, the electrolyte leakage phenomenon described above is particularly troublesome because it states that the spot contact must penetrate through two separate plastic foils before it comes into contact with the zinc mass.

The object of the present invention is to improve the structure of the above-mentioned time-lapse disk batteries so that electrolyte leakage from the cells cannot occur as described. The invention also facilitates the industrial manufacturing process of batteries. At the same time, the quality of the batteries is also improved because the cells are made homogeneous with each other, due to the uniform thickness of the zinc mass layers and the fact that the contact spikes penetrating the zinc mass have a clean surface and are free of insulating layers.

The invention is characterized by a cell structure as defined in the claim. A preferred embodiment thereof which achieves the above-mentioned advantages, as well as some other structural improvements, will become apparent from the following drawings and related descriptions.

Figure 1 shows a side view of a cell battery cell provided with a stiffening 1 according to the invention.

Figure 2 shows a top view of a rigid sheet according to the invention and a sealant applied to this sheet.

Figure 3 shows a side view of a second embodiment of the invention, in which the stiffening plate is arranged as a cell shell

II

3,81462 inside a working plastic foil cup.

Figure k shows a 6 volt battery according to the invention, corresponding to battery type 4 L R 2 5.

In Fig. 1, the positive electrode comprises a hard-pressed pulp tablet 1 having the same composition as in the above-mentioned known early-runon stone batteries, an electrolyte-repellent, electrically conductive carbon mass layer 2, an iron plate 3 and a steel spike welded thereto. Between the iron plate 3 acting as a current collector and the plastic foil 5 acting as a cell cover, there is a thin tight paste layer 6, which is e.g. adhesive 1 atibibitum and prevents the electrolyte from entering the contact peak k and the cell shell foil 5.

The negative electrode is a paste 7 containing gelled amalgamated zinc powder, KOH solution and this electrolyte-binding gel, such as CMC, prepared in a known manner and sealed in a flat, uniformly thick package in the same manner and in a heat-sealable nonwoven fabric similar to U.S. Pat. in Patent No. A, ^ 87,021 is shown in Figure 6. On each side of this electrode package there is a cup-like layer 8 of electrolyte-absorbing felt, e.g. rayon, reinforced with polypropylene fibers. This electrolyte-charging felt material 1 in should weigh about 200 g / m 2, as it has been found that the free electrolyte absorbed into the nonwovens must be abundant on both sides of the zinc mass to achieve efficient diffusion, resulting in a zinc utilization efficiency of 85-95%.

The parts 1, 7 * 8 are stacked in a plastic foil cup 9 acting as a cell shell. · The lower electrolyte felt 8 has a round hole 10 stamped in the middle to facilitate the passage of the contact spike. When, as the last step of the cell assembly, the lid foil 5 is heat-sealed in a vacuum along the edges of the cup 9, an airtight cell is formed, and the outside air forms the zinc paste bag 7 so that a lens-like thickening forms at the hole 10 at the contact point.

* · 81462

In Figure 1, a stiffening 1 evy 11, e.g. In Figure 2, this plate, which is a rigid but sharp metal, is readily permeable to plastic, e.g. in a 4R25 type battery 0.25 mm to 0.4 mm PVC, impact resistant polystyrene, HD polyethylene or polypropylene. For each battery type 1 1 e, depending on its size and quality, the appropriate stiffening 1 plate material and its dimensions can be optimized by experimenting. This stiffening plate can be, for example, round or rectangular in shape, and it is advantageous if it is slightly convex outwards in the middle, so that when the contact peak penetrates through it, the plate does not buckle inwards. This avoids the formation of an air bubble causing electrolyte leakage at the root of the contact peak.

Figure 2 shows the stiffening plate 11 from above, coated with hotme1t-I i ima layers 1 1 a 12. In dimensions, this plate can be approximately half the width and length of the cell. It is sufficient that the layer of hotmelt or other sealing paste 12 covers only a small area, e.g. 2 cm in diameter, in the middle of the stiffening plate, and in the factory battery product such a layer is on both sides of the stiffening plate. When such a plate is pressed against the bottom of the cell, the next cell is immediately pressed with this s Arja connection, and the electrolyte tight contact from the positive contact of the latter cell to the zinc electrode of the previous cell is formed. Compared to known structures and methods, a qualitatively more reliable product is achieved in a surprisingly simple manner.

The principle of the invention, which essential part is placed on the negative side of the cell kuorikalvoon reinforcement that can be implemented in many different ways. In Figure 3, such a stiffening plate is placed inside the cell cup. This plate 13 is attached by hotmelt gluing, hot or ultrasonic melting to either the plastic-1 amino acid before or after the hot molding of the cup. The advantage of this structure is that the stiffening plate effectively cleans the sealing paste of the contact peak before it penetrates the zinc coating. The disadvantage is that when assembling the battery, an additional step is required to apply the sealing layer 14.

II

5,81462 to the outer surface of the negative shell surface of the cell to provide a leak-proof penetration. Of course, heat or ultrasonic coating can also be used in the structure according to Fig. 1 instead of gluing, especially if multilayer-1 amine is used as the cell shell, the outer layer being sealable with the stiffening plate. Of course, a thinner stiffening plate can also be welded to each side of the cup either before or after it is formed in a deep drawing machine. The stiffness of the plate 11 can also be increased by shaping the ridges and grooves used for this purpose in a known manner.

Figure h shows a battery according to the invention. The negative end plate 15 is an iron plate to which a contact yoke is welded. Attached to this plate is a dashed wire 16 to the contact spring 17. At the positive end, the contact spike is partially cut off, and the wire 18 welded to it is attached to the second contact spring 15 at one end. Practice has shown that the cells should not be compressed with great force, because then the electrolyte absorbed into the cup 8 is squeezed out between the cell parts, where it is needed when the battery is operating. A 0-ring around the 23 positive contact points ensures that the electrolyte cannot leak out of the battery under any circumstances.

Claims (1)

An improved structure of an alkaline disk battery, characterized in that a stiffening plate (11) is attached to the end wall of each cell on the zinc electrode (7) side, which resists inward bending of said end wall when the contact spike (4) is pushed through said end wall (7). The construction of the alkaline skate battery, which also comprises a shielding cell, is provided with a sheave (11) which is connected to the main electrode (7) side; vilken skiva hindrar nämnda gavelvägg frän att böja sig inät när en kontaktpigg (4) inskjutes genom nämnda gavelvägg i skiktet (7) av zinkmassa. Il