Dry cell.

AS AFRICAN AND MALAGASY INDUSTRIAL PROPERTY PATENT

P. 887

In Yaounde (Cameroon) International Patent Classification : HR 01|VBE1|01732 DEGREES

O A. M.>E. I REQUEST THE 28 may 1965 to 16 hr 30 1 min. to the O.A.M.P.. (PP.V. N° 51,912) by

residing in France.

DELIVERED 15 December 1969

Publishes official ballot at no. 4 of 1969

PRIORITY:

the 1 June 1964 no. 976,643/sec.

20 november 1964 no. 995,716/sec.

on behalf of the applicant.

The present invention relates to a dry cell having at least one primary electrochemical element whose outer part is a cup, said stack being enveloped by a plastic liner and closed at its upper portion 5.

Many embodiments have already been proposed to avoid the leakage of electrolyte out of such cells, by various means providing ' good seal at the bottom of the cell and hence the 10 bottom of the plastic liner.

In particular, it has been proposed to mill the lower portion of the plastic liner in order to be able without oversize folded down against the bottom of the element.

15 Sealing at this level is then achieved by clamping the plastic either between a metal ring and the bottom of the element, either between a metal ring and a metal washer held against the bottom of the element.

Such embodiments are not without drawbacks, because they require, to be effective, the use of parts to highly accurate dimensions, and therefore is of actual difficulty, especially for the bucket of 1' element.

On the other hand, that is also flexible plastics used, cannot be expect by a simple crushing a true seal resists the action of high internal pressures.

Finally, this construction almost completely the use, as a soluble anode material, ^ of the lower part of the walls of the primary electrochemical element, receiving section receives the metal ring to provide 1' seal by compression of the plastic material.

By designing indeed easily that if the lower part of the wall of the element were to participate in the dissolution process that accompanies the flow of electrical power, the clamping obtained by compressing the plastic would not in its initial state and the risks of leakage of the electrolyte would increase accordingly.

the aim of the present invention is to provide simple and inexpensive means by a true seal at the bottom of the plastic liner, this seal to be able to withstand high internal pressures, with a stable performance under any conditions or use of the GMR stack.

For this purpose, a stack according to the invention is primarily characterized in that the jacket is clamped at its lower part between the hem of a basin and a seal on the outer periphery of a thickened portion provided on the bottom of the beaker.

In one embodiment of the invention to which it seems there is place of giving preference, the seal is placed into a groove provided on the outer periphery of the additional thickness, groove that may be trapezoidal in cross section.

Advantageously, the cup and the additional thickness are obtained in one piece by extrusion and the groove is then machined in the suré aissor - ^.

In one embodiment, the extra thickness provided as part of an independent metal, who wants to be joined to the bottom of the pot by welding points.

By designing that, by these arrangements, the seal is sufficiently compressed between the walls of the groove provided in the thickened portion and the lower portion of the plastic liner to ensure, by virtue of its elasticity, the required seal ., this as soon as the top of the raised rim of the bowl is folded inwardly, by a simple operation that can be assimilated to a crimping. The Sn also, the cup cannot, in any case, be torn, even if significant internal pressures develop within the stack and communicate in the space between the cup and the jacket. Finally, the manufacture of the various components of the stack is not difficult would affect the cost.

It should be noted however that it is necessary, either for providing electrical contact between the cup and the cup, or it allows other means at the bottom of the stack form one of the power outlets.

It is for this contact that, in a particularly simple construction, the bowl rests on the extra thickness and further comprises advantageously a recessed dome resting on the bottom of the bucket.

For some applications, however, it may

be advantageous in that no electronic connection cannot be established between the taking of negative polarity of the battery and any other metal part of a user apparatus in contact with the sidewalls of the stack.

For this purpose, a first solution consists in providing, for example using a varnish, isolation from outside the raised edge of the metal tray.

However, in an arrangement falling within the scope of the invention, the bowl can be widely apertured and isolated, by interposing a washer, a disk bearing on the allowance. Here the disk in question which provides the socket.

In one embodiment, the basin can be widely open and be in contact solely with the jacket and the seal, the excess being of sufficient height to reach at least leniveau LED ' ajcur 3a of bowl. Here the allowance itself which provides the socket.

The invention will be clearly understood in any case

by referring to the description which will follow, made opposite the accompanying drawings which show, as non-limiting examples, a number of embodiments of the invention and in which T

figure 1 - in cross-section represents a primary electrochemical element, cup-shaped, in a first stage of fahrication;

figure 2 - represents the same element in a second stage of manufacture;

figure 3 - sectional always watch, in exploded view, all the constituent parts of a dry cell according to the invention;

fig. 4 shows always - sectional, after mounting the dry cell *

figure 5 - is a partial view always sectional, enlarged scale but the stack according to Figure 4:

figures 6 - 8 show the same to variants.

Measured by the first Figure 1, see it represents a metallic housing 1 preferably made of zinc.

According to the invention, on the bottom of the pot, and to the part rérvehérique, a surénaisseur 2 has been provided. For execution facilities during the extrusion of the pot, the outer diameter of the surénaisseur is the same as the diameter of the bucket benzoylacetanilide dir cleanly, but it is pointed out that does not exit the the scope of the invention in rrévoyant this diameter smaller than that of the bucket.

It is emphasized further that during extrusion from a zinc pellet, it is very easy to obtain the extra thickness 2 - l'experience shows same as results in wear on the extruder relative to wear recorded for obtaining ordinary buckets.

Figure 2 shows that on the outer periphery of the extra thickness 2 has been machined a groove 3 circular, trapezoidal in cross section and a few millimeters depth.

Figure 3 shows that the bucket 1 which serves as a soluble anode material to the stack, receives at its bottom an insulating piece 4 and then the electrolyte optionally with its support 5, then the depolarizing mixture 6 agglomerate around a central electrode 7 formed for example by a pencil of coal.

Above this element, then disposes a jacket 8 generally cylindrical flexible plastic such as polyethylene, polypropylene or vinyl chloride, liner for one hand to close the open top of the stack and, on the other hand, to enclose the side walls of the bucket zinc 1. This jacket has a known manner an orifice 9 of diameter slightly smaller than that of the center electrode 7 which must pass through it, vent with a appendix 10 increasing height of bushing. After placement of the liner, the assembly is completed by a metal capsule 11 brass for example that is fitted onto the center electrode.

These various constituents are completed, in accordance with the invention, by a circular gasket 12 made of rubber or any other inert material and flexible. This circular seal, whose cross section is preferably O-ring is sized to fit within the circular groove 3 by being fitted with a slight forcing action.

Finally, underneath the joint shone in a stamped cup 13, thin metal, e.g. tin-plated iron.

This cup which will be described in detail in front of Figure 4 is of a diameter slightly greater than that of the plastic liner 8.

figures 4 and 5 show, how after forming the components 1 to 12, is capped by a metal disk 13 the lower part of the jacket, that extends slightly below the level of the seal 12 when the folder itself comes to abut the top of the cup on the wafer made of zinc.

Followed is a crimping operation on the metal edge of the basin 13, which rests on the extra thickness 2, and finally the O-ring is greatly collapsed against the circular bottom of the groove on the one hand and against the liner 8 on the other hand.

It thus appears clearly that it becomes impossible, irrespective of the pressure exerted, tearing the basin 13 by the O-ring retainer 12 that abuts on the wall ' - inclined outer - of the groove 13.

FARs also, in case of an abnormal use of the stack, and if the electrolyte tends to be rejected out of the bucket, the electrolyte will fill the free portion located above the cathode and even flow between the liner and the cup 1 8.

However, at the lower portion thereof, it will encounter the seal 12 which will oppose perfectly to its passage and will therefore ensure a complete seal. It cannot therefore, case Y liquid leak outwardly TDC you do will observe a slight forward metastases at potential deformation of the sleeve 8.

Is will be recalled in this connection that sealing is ensured at the top by the appendage 10 which clamps the center electrode 7.

Finally, it is important to ' observe that the jar of zinc can be used as a primary element over its entire height without that nothing can affect the efficiency of the O-ring 12 since the latter rests on the extra thickness 2, which is perfectly sheltered by electrochemical effects the operation of the cell.

Referring still to fig. 4 or optionally to the enlarged view of Figure 5, it is established that the basin 13 which bears on the surépaissaur 2 is further provided with a central cap 14 engaging the central area of the bottom of the loader 1? this contact that is additive to that made 15 at the surépaissaur 2 allows the bowl form taking negative polarity of the stack.

It may however prove necessary, for certain uses stacks of the type described that no electronic connection is no - seizure between the negative polarity of the battery and any other metal part of a user apparatus.

A first solution to achieve this objective of providing isolation from outside the raised edge of the metal tray 13 obtained for example by means of a " enameled lacquer.

Alternatively, as shown in Figure 6, to use an apertured metal bowl 17 and isolate a metal part 19 disposed resting on the bottom of the bowl or on the allowance, alone obtained by interposing an insulating washer 18. In the latter case, the metal disk 19 acts as a handle negative polarity * however, the bowl 17 has no connection with the bucket éleetronique allowance by 1 or 2 which it setrouve perfectly separated by the sleeve 8 and by the insulating disk 18. A possible contact of the cell with a metallic object adjacent a user apparatus is therefore safe.

According to yet another arrangement for isolating the bowl and forming - part of the present invention, is shown in Figure 7 arrangement, use is made of a metal bowl 20 largely ajouréer 21 the extra thickness of the bowl bottom metal 22 as well as the gasket 23 are then chosen shapes such that, during the crimping operation, the metal tray 20 is bearing against a portion only of the joint without contact with the underside of the base member or piece pressed against it. The esnace intermediate between the edge OD the bowl and the projecting portion of the bottom is occupied by the upset portion of the insulating ring under the clamping pressure of the metal tray.

Herewith the combination of the groove 7 taken from the bottom of the element, the seal 23 contained therein and bowl 20 clamping, both in sealing and electrical insulation OD this cup.

The stacks described according to Figures 1 to 7 all comprise a metallic housing forming a single piece with the extra thickness into which has been machined a circular groove.

However, if it is perfectly possible in the case of a metal such as zinc to obtain a cup of the shape indicated above by extrusion, it is not OD even with other metals such as magnesium and iron, for example, fan this case, it is necessary to apply other facilities such as that shown in Figure 8.

The stack according to Figure 8 differs from the preceding in that the metallic housing 24 serving as an anode has, as usual, a flat bottom as shown the I ' ohnir readily both by drawing that extrusion, but to the lower part of EO bucket 24 is located another metal part 25 forming part of the invention and that has a thickened peripheral portion 26 into which has been machined a circular groove 27 of trapezoidal section and a few millimeters depth, wherein to receive the seal 28.

Advantageously, the metal part 25 will be selected the same type as that of the bucket 24. It will also benefit welding the piece 25 and the cup bottom 24 therebetween, for example electrically, at one or more points 29 to obtain a perfect electronic connection.

The mounting of the stack according to Figure 8 is identical to that which has been ℮χη licité facing of Figures 1 to 5.

It is also clear that the invention is not limited to the examples described above, but that it would be possible, on the contrary delivered thereto various changes without departing from its scope.

In particular, it may be noted that under the term

"stack" of has been designated a set comprising at least

a primary electrochemical element. It emerges clearly that the invention is applicable in the case of the series connection of two or more elements arranged end to end within a single plastic liner, provided that the seal at the bottom of the shirt is ensured by clamping between the hem of a bowl and a seal carried by the trough of the lower member.

On the other hand, the examples of Figures 1 cells described according to 8 relate to dry cell batteries having a metallic housing serving as an anode. Of course that this disclosure is not limited and that the pot metal could merely providing a current collector and a non-sacrificial electrode; this is particularly true for certain alkaline cells whose anode is a cluster of zinc powder applied against a metal collector; this would also be the case of other alkaline cells whose depolarizing mixture is applied to the periphery of the member against, a metal collector, the center electrode then constituting the nrise negative polarity.