US 2861117 A
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Nov. 18, 1958 J. SINDEL GALVANIC PLATE BATTERY Filed May 5. 1955 United States Patent GALVANIC PLATE BATTERY Johann Sindel, Ellwangen, Jagst, Germany, assignor to Pertrix-Union G. m. b. H., Frankfurt am Main, Germany Application May 5, 1955, Serial No. 506,291
4 Claims. (Cl. 136-111) In the manufacture of galvanic cells it has been found to be advantageous to enclose the structural elements of a cell in two plastic cups which are facing each other at their open ends, said cups being provided with openings for making electrical connections. In this device the rim of the lower cup which lies inside, is moldable more easily so that, upon pressure building up in the interior, the rim of that cup is pressed against the rim of the upper, outer cup, whereby the sealing of each cell against escape of electrolyte is improved.
Pressures are principally contemplated which arise in the assembly device when individual cells are combined to a group of cells; however, the increased safety to leakage will also be of value when the interior pressure rises during discharge or during storage in tropical climates.
The present invention relates to a further development of the above described device. According to the invention the inner, lower cup is made of a synthetic or synthetic-like material which has the property of becoming deformed when subjected to slight rise of temperature. When this happens, the rim of the inner cup will bend outward and provide a safe sealing, although no increase in pressure is taking place.
This effect can be obtained by adequate selection of wall thickness, by applying the proper shaping process, choosing the right materials, and operating at the suitable temperatures of shaping and processing.
When the inner cup is made, e. g. from a thin drawn foil of acetyl cellulose, the material flows less profusely at the outer rim due to less heat reaching that area. This part of the cup has the tendency upon a slight increase in temperature to return to its former position and therefore presses the rim outwardly. A similar eifect may be obtained when cups drawn from thicker material, consisting e. g. of PCU, are used and the drawing temperature is maintained at such a low level that the material flows incompletely. In such cups the rims have likewise a tendency of bending outwardly upon heating.
Finally thermoplastic materials, rubber, or rubber-like materials may be formed into cups at a temperature above their solidifying range, whereupon they are used for enclosing the structural parts of the cell below the temperature at which they lose their plasticity and elasticity; then, after assembly has taken place, the cups are again heated up to a temperature above their solidifying temperature so that they bend outwardly due to internal tension.
2,861,117 Patented Nov. 18, 1958 In all the above described methods an outer cup may be used which may be e. g. rigid, extruded or drawn; the outer cups may or may not have some of the properties described for the inner cup. Thus the wall thickness of the outer cup may be larger, the shaping process may be a different one, more rigid materials with more or less softening agents, higher shaping and solidifying temperature, etc., may be used than in the inner cups to be combined with said outer cups. One or several of the mentioned differences of materials or shaping characteristics may be present, as the case requires.
The cell according to the invention will now be more fully described with reference to the accompanying drawing, but it should be understood that this is given by way of illustration and not of limitation and that many changes in the details may be made without departing from the spirit of the invention.
In the drawing:
Fig. 1 is the outer cup;
Fig. 2 is the inner cup;
Fig. 3 shows the composed galvanic cell.
Referring to the drawing 1 is the outer cup, 2 the inner cup, 3 is a depolarisator, 4 a zinc electrode, 5 a conducting layer, and 6 the electrolyte carrier.
What I claim is:
1. As an article of manufacture, an enclosure for a galvanic cell, said enclosure comprising an outer cup and an inner cup, each said cup formed with a bottom portion and a rim portion, each of said bottom portions having a central opening therein, said rim portion of the outer cup being in overlapping and fitting relationship with said rim portion of the inner cup, the said bottom portions of said cups being spaced from each other for enclosing the galvanic cell, said inner cup being coldpressed of a material having a lower temperature at which internal mechanical stress becomes released than has the material of which the outer cup consists, and having the property of becoming deformed and having its rim portion bent outwardly when subjected to a slight rise in temperature above said stress relieving temperature; said outer cup made of a material less deformable by such slight rise in temperature, said enclosure having the rim of the inner cup in sealed relationship with the rim of the outer cup when at normal temperature, after having been subjected to such slight rise in temperature.
2. The article of claim 1, wherein the inner cup is formed from a thermoplastic material.
3. The article of claim 1, wherein the inner cup is formed of acetyl cellulose.
4. The article of claim 1, wherein the inner cup is formed of rubber.
References Cited in the file of this patent UNITED STATES PATENTS