US1509650A - Hermetically-sealed dry cell - Google Patents

Description

5. w. HEI SE' HERMETICALLY. SEALED DRY CELL Filed Jun'e 5Q. 1921 till) hil l' atented Sept. 23, 1.924.

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GEORGE W. HEISE, F ELMHURST, NEW YORK, ASSIGNOH, T0 NATIONAL CARBON comrenv, mo,

A CORPORATION OF NEW YORK.

HEEMETICALLY-SEALED DRY CELL.

Application filed June 30, 1921. Serial No. 481,715.

To all whom it may concern Be it-knovvn that l, GEORGE WV. Hnisn, a-citizen of the United States, residing at Elmhurst, in the county of 'Queens and State of New York, have invented certain new and useful lm rovements in Hermetically-Sealed Dry ells, of which the following is a specification.

.Tlhis invention relates in general to the prevention of detrimental gas pressure in dry cells. More specifically, it comp-rises the use of reagents capable of fixing gases evolved in hermetically sealed cells durin 'their storage or shelf-life period.

it is known that the pro-service deterioration of -dry cells is due in large part to the non-hermetic character of the seal. Moisture continuously escapes through crevices between the seal and the electrodes or through the pores of the carbon rod, and it is probable also that air enters throu h these openings, increasing zinc corrosion by depolarizing the centers of local action.

lt'leretofore it has been regarded as impracticable to provide a true hermetic seal on dry cells of standard construction and reagent composition because of the evolution of ga es,- position of the mix, or other causes. nless these gases find an exit, the internal pressure may become sufficient to distort or rupture some portion of the cell. It is an object of the present invention to provide a hermetically sealed cell in which the generation of excessive gas pressure is prevented. This object is. attained. by scaling to the cell a removable impervious cap which may be so constructed as to form an expansion chamber having avolume adequate to receive cell gases Without an excessive development of pressure.

Reagents capable of fixing the evolved gases in the form oi compounds having low vapor pressure at ordinary temperature may be used in such cap-s as an additional protection against the accumulation of gases. Ur, when the reagent employed is an active absorbent, it maybe supplied in a sealing cap of relatively small volume.

The invention will. be described in detail in connection with the accompanying drawrug, in whichig. l is a vertical longitudinal section through a hermetically sealed cell,

due to local action, decom- Fig. 2 is a fragmentary side elevation showing the sealing means, and

Fig. 3 is a vertical longitudinal section through a cell having a modified form of cap Which contains agas absorbent.

Reference numeral 1 denotes a zinc con tainer, 2 a lining of bibulous material and 3 a mix bobbin containing a carbon rod 4. The zinc container has a marginal depression 5 to which a binding post may be attachedso as to lie Wholly Within the outline of the container. A plastic seal 6 of the usual type is provided. This seal is nonhermetic but-is sufficiently close fitting to prevent undue evaporation of moisture after the removal of the absolutely airtight closure now to be described.

The hermetic seal comprises a cap 7, of metal or other impervious material, having a cross section corresponding to that of the container 1. The cap and container, placed with their margins in abutting relation, are secured together by means of a band 8 overlying their junction. The band 8 may be attached in any manner Which will give a secure and air-tight joint, as, for example, by soldering it to both the cap and container. A tongue 9 is provided on the band 8 'and'is' adapted to be passed through an opening 10 in key 11. When it is desired to remove the hermetic sealing cap 7 the band may be severed by engaging the tongue in the key and rotating the latter to tear the metal along the lines of the sides of the tongue extended, in a Well known manner. A clip 12 may be provided on the to of cap 7, or elsewhere on the cell, for hoding the key in handy position.

The cap preferably has a volume about five times as large as the volume oi gas, measured at atmospheric temperature and pressure, which will normally be evolved from the cell contents. Experience has shown that a cap about 1 inches in height is suitable for application to 6 inch cell, and the same relative proportions may be used in sealed cells of other sizes. The volume of a cap of this type is relatively very large as'compared to the interstitial volume below the pitch inner seal. F nch an expansion chamber is capable of receiving without undue strain a quantity of which would exert a distorting or. disrupt ing pressure ii confined below the inner seal. The cap is preferably made of thinner metal than the usual zinc can and is formed with a concave top which can spring outwardly into convex shape to enlarge the ex pansion chamber, should the pressure of the gas require it.

of gas pressure in hermetically sealed cells is the formation of carbon dioxid b interaction ofthe mix and electrolyte. ilocal action upon the zinc is substantially prevented by sealing the cell from contact with air, so that the hydrogen production is negligible. As carbon dioxid is the only gas which under ordinary conditions is likely to cause excessive ressure, hermetically sealed cells maybe adiiquately protected by the use of an alkaline absorbent. Hydrated lime may be mentione by way of example, as a suitable material. A large number of alkaline solids capable of reacting with carbon dioxid at ordinary temperatures are known, however, and my invention includes the use of anv of these bodies.

As shown in Fig. 3, a cap 13 is sealed upon a cell in the manner described above. A material 14, such as lime, is contained in I have discovered that the principal cause the cap and is preferably spaced from the carbon electrode by an heavy paper or the like.

line liquids as absorbents of'carbon dioxid is also within the scope of my invention. When these are used, any suitable precautions may be taken to prevent electrical conmotion between the carbon and zinc inverted cup 15 of The use of alkapoles.

Another convenient way dioxid is by the use of ammonia gas. may be introduced into the of ways,

This cap in a variety for example by evacuating the cap through a suitable opening, passing in ammonia, and sealing the opening. Carbon dioxid evolved from, the mix will pass through crevices between the plastic seal 6 and the electrodes, or through pores in the carbon rod and spacing cup 15, into contact and combination with the ammonia, lime, or other absorbent.

Instead of supplying a material capable of reacting with carbon dioxid, the same ultlmate result may be obtained by the use of any gas or vapor which will react chemically with a the cell to produce a solid gen produced by local action on the zinc,

the corrosion of the metal being accelerated by the presence of the oxygen, or it may be fixed in other ways, as by the formation of of fixing carbon.

or liquid compound. In this zinc oxid. The reduction of pressure within the cell produced by the union of oxygen with hydrogen, zinc, or other substances is appreciable even when the cap contains air. The amount of oxygen in the ca is inSufiicient to produce the harmful eii ects which would be caused by continued ingress of air, if the seal were non-hermetic. In some cases, also, ammonia supplied as described above, may react to .form compounds with zinc chlorid or other cell constituent, before having 0 portunit to combine with carbon dioxid. 1e resut of such reaction is a reduction of gas volume compensatin for subsequent generation of gases in the cc 1.

When the cell is to be put in service, the sealing cap will be disconnected as described and the spacing cup removed from its position over the carbon pole. The serv ice characteristics of cells so protected from the deleterious effects of access of atmospheric oxygen, or other causes due to incomplete isolation from the atmosphere, will be found substantially equal to those of freshly pre ared cells.

The above described ex ients for preventing gas pressure may b: used singly or in any desired combination according to the requirements of any particular case. If gases other than carbon dioxid are given off in objectionable quantities, a suitable spe' cifio absorbent for such gases may be read ily selected in accordance with known chem ical properties. Some of the beneficial results of my invention may be obtained in non-hermetically sealed cells, as, for exam' ple, by placing a layer of gas absorbent material below the pitch seal. The shape and mode of attachment of the sealing cap may also be modified to fit it for use with cells of non-cylindrical type, and various other changes in construction and relative arrangement of parts may be made withln the scope of the appended claims.

I claim:

1. A dry cell containing a material capable of react-ing'chemicully with a substance in said cell to produce a reduction of pressure in said cell.

2. A dry cell containing a material capable of preventing excessive gas pressure therein by chemical combination with gas evolved from cell constituents.

3. A dry cell containing an alkaline ll) sorbent material capable of fixing gas evolved in-said cell.

loss of moisture,

reacting chemically with gases generated in the cell.

7. lln a dry cell a hermetic seal comprising a cap having a volume adapting it to serve as an expansion chamber for gases generated Within the cell.

8.; in a dry cell, a seal permitting the passage cf gases, an air-tight cap enclosing said. seal and a material in said cap capable of reaclin chemically with gases generaiecl in the cel 9. In a dry cell, a seal permitting the passage of gases, an air-tight cap enclosing said seal, anol a material in saiel cap capable of reacting chemically Willi gases generated in the cell, said cap having a top capable of yielding without rupture under gas pressure.

In testimony whereof, I allix my signalure.

GEQRGE HEISE.

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