US1370055A - Dry cell and method of manufacturing the same - Google Patents

Description

. w.,.. SCHUHE. DBY CELL AND METHODOF MANUFACTURING THIAS'AMF. 4 APPLICATION met MAY fsw; 1929;.v

UNITED STATES PATENT roFFlcE.

WALTER is. sCIIoLTE, or MADISON, wIsCONsIIxI,` AssIGNOR TO BURGEss BATTERY' COMPANY, A CORPORATION or WISCONSIN.

DRY CELL ANnMETIIon OF MANUFACTURING THESAME.

do hereby declare the following to 'be a full,

clear, and exact description ofy the invention, such as will enable others skilled in the art to which it appertains to make and use the same. 5

The present invention relates Ato dry cells and particularly to the cathodes of suchv Cells, and to the method by which the cathodes are provided with a wrapping of bibulous material to prevent the electrode from disintegrating into the electrolyte, particularly` during the assembly of the several parts into a complete dry cell.l

It is an object of the present invention to eliminate ,air bubbles within the bibulous envelop or between the envelop and the gelatinized paste commonly used in dry cells of the sO-called bag` type. f

It is a further object of the invention to eliminate -some of the tedious hand labor incident to the use of'a cheesecloth bag or envelop held` in place by a wrapping of thread.

Other objects and advantagesof the present invention will be made Aclear vby the following detailed description, which is to be taken in conjunction with the accompanying drawings, wherein Figure 1 is a perspective view of a dry cell cathode constructed in accordance with the present invention, and Fig. 2 is a sectional elevation through a complete dryfcell.

In the manufacture of dry cells, ,it is customary to prepare a mixture or mix of manganese dloxid, such as pyrolusite, together with' carbonaceous material,.su ch as graphite and retort carbon, and'usual salts and water as explained, for instance, in BurgessU.S.15 ber 30, 1915, and then to compress this damp and plastic mixture about a carbon rodlto form al core, or cathode, for the dry call. Thismolding. of the plastic mix into cylin- Specication of Letters Patent. v Application l'ed Hay l1li, 19,20. Serial No. 381,653.

atent No. 1,162,449, dated Novem- Patented Mam, 1921;

drical form with a carbon rod in the center may be Adone lin suitable apparatus, as, for instance, inthetamping machine of Hambuechen U. SI Patent No, 1,232,297, dated July 3, 1917. r1"he cathodes so formed, although strong enough for. manipulation on a' factory basis, are nevertheless fragile in character and subject to disintegration, Y

particularly if their moisture content isv changed substantially from that at which they are molded. As'they come from the molding machine, ready for wrapping, they are s0,4 soft that it is possible for. the operatorl easily to crush them between his -thumb and forefinger.

A customary molded cathode Vfrom disintegration during the further 'steps in the assembly is to wrap vthelcore with cheesecloth. The cheesecloth ordinarily used isa fine grade, unsized mater1al, and 1n conformity with usual pracwrapping of thread. The cloth is brought wayof protecting such a.

A tice, is held in'place around the core with a around the bottom-,of the core and over the top, and the thread is wound ',not `only around the perimeter of the core,- but also longitudinally and parallel with the carbon Y.

pencil. The wrapped core so produced can then'with advantage be dipped vinto a very shallow 'layer of melted paraffin to form an insulating layer or film across the bottom, as

explained, for instance, in Burgess U. S.

Patent No. 1,211,363, dated January 2, 1917.

.The cheesecloth is expensive, and the operation, of winding the wrapped cores with thread, being a hand'operation, is tedious and likewise expensive.- Also, there is danger that through unskilled handling, the

v soft and plastic' cores will be deformed.

Also some of the activemixmay nd its way to they outside of the cheesecloth wrapping, and on assembly of the dry cell, be washed over into' contact with the zinc, where it can produce local action with destructive results.

In conformity with the method of the present invention, the `bibul'ous envelop or" wrapping for the cathode is held in place, not by winding with thread, but by means of an adhesive. This method permits the tionable.

" the most suitable is one that is thin but use either of paper or of cheesecloth as the bibulous material, and there is some economy in labor. But of more importance than'this is the gain in the quality of the 6 dry cell because of the absence of air bubbles within and without the bibulous enl v'elop, as hereinafter explained more at length.

If cheesecloth is to be used as the bibulous 1`0 envelop', it may be Iof the quality .now commonly used for this purpose. I paper is to be used, as the wrapplng, it should be a od uality,'-thin and porous tissue paper. slig tly calendered surface is not objec- The adhesive which I have found does not settle. A starch ,paste suitable for this work may be made by adding arrowroot to boiling water to the extent of about 20`one per -1 cent. by weight, though other The procedure for applying the envelop to the core consists in dippingv each molded core into the arrowroot solution and then, while the core is still wet from the adhesive, Wrapplng it with the drycheesecloth or v paper and folding down'the wrapping at both ends of the core to cover its top nd bottom, care being taken to press out any air bubbles and to secure intimateunion between the wrapping andthe sticky surface 10 beneath. This operation calls for some skill and jud ent. The diiliculties are' that the core is iable to an incipient breaking up `when it is dipped into the adhesive, thereby soiling and lmpairin the adhesive. Furthermore, the coreta es up in its poresan appreciable quantity of the adhesive, therebag type having a bibulous envelop pasted by becoming softer and morev diicult to manlpulate durin subsequent manufacturlng operations. fter being wrapped, the

I l cores must be separatedfrom each other in the trays during the' time that they" are drying, as otherwise they may stick,v to one,

another because of the soaking through of some of the adhesive' held by the core.

There is a tendency, also, for the carbon to loosen from the core just during the time that the paste is setting. These dificulties are not, however, serious, and onceappreciated, can be adequately guarded against.

After the cores have been wrapped and dried, they can be yintroduced into their respective zinc cups and a gelatinizable electrolyte can be poured in to fill the space between the zinc and the bibulous envelop.

Then, after cooking or such other treatment,

\ concurrently herewith, I have described and if any, as is necessary to gelatinize-the electrolytic paste, the cell can be nished oii' in usual manner.

The construction above described is illustrated in the drawing, where 1 is the car- 70 formed by dipping the core into a thm layer of meltedparain. 7is the zinc electrode or anode, 8 lis the gelatinized-paste, 9 is a par` 80 aHin paper washer, and 10ris a layer of pltch or sealing wax. A

Becausevof the method by which the envelop is applied to the core, no air bubbles need be entrapped between it and the core.

EnoughA of4 the adhesive comes out of the pores of the core to lill the pores of the wrapping, and, consequently, after 'the core has .been placed in its zinc cup, and the gelatinizable electrolyte hasv been introduced, the electrolyte will wet and make good contact with the outer face` of the" starch-filled envelop, thereby avoiding entrapment of air on the outer face of the' envelop. The envelop is of uniform electrical conductivity, and because of the ab sence of. air bubbles, vthe Hash of the bat- The process effectsa saving both of labor and material, and permitsl the tery ishigher.

easy substitution 'of paper for the more yexpensive cheesecloth wrapping no-W commonly used.

It is not readily feasible vmerely to suby stitute paper for cheesecloth and wrap it around with thread, for the paper is. stiif and tears, Vand air bubbles are formed within the envelop which give a low flash to the battery and otherwiseimpair its quality.

Inmy application Serial No. 381,652,f1led claimed broadly a dry cell'v cathode of the in place, and I have claimed the step which consists in pasting the bibulous envelop to the cathode preparatory to addition of the electrolyte.

vI clalmz- '1. A dry-cell ycathode impregnated in part, at least, with an adhesive, and having a bibulous envelop held in place by said adhesive substantial y as described.

2. A dry-cell cathode impregnated in part, at least, with a starch adhesive, and having a bibulous envelop held in place by said adhesive substantially as described.

3. A dry-cell cathode impregnated in part, at least, with a starch adhesive, and 'having a paper envelop held in place by j said adhesive, substantially as described.

4. In the manufacture of dry-cells, the 180 ammat-ically illus- `I5 steps which consist in partially impregnating a molded cathode with an adhesive, and then wrapping said cathode with a, bibulous envelop and thus securing said envelop in place, substantially as described. A

5. In the manufacture of dry-cells, the steps which consist in partially impregnating the molded cathode with a starch adhesive, and then wrapping said cathode with a paper envelop and thus securing said en- 10 velop in place, substantially as described.

6. In the manufacture 4of dry-cells, the steps which consist in dipping the molded cathode in a suitable adhesive, and then wrapping said cathode in tially as described.

In testimony whereof I aiix m si ature.

WALTER B.SC TE.

paper, substan- 15

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