US3623915A

US3623915A - Electric dry cells

Info

Publication number: US3623915A
Application number: US842274A
Authority: US
Inventors: Ching-Koon Pun; Ching-Chau Poon
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-07-11
Filing date: 1969-07-16
Publication date: 1971-11-30
Anticipated expiration: 1988-11-30

Abstract

AN ELECTRIC DRY CELL HAVING THE OPEN END OF ITS CUP ELECTRODE CLOSED BY A MOULDED PLASTICS PLUG WHICH IS GRIPPED AROUND ITS PERIPHERY BY THE INTURNED END OF THE CUP AND HAS A CENTRAL APERTURE EMBRACING THE ROD ELECTRODE, ANNULAR SPACES FILLED WITH SEALING MATERIAL BEING PROVIDED RESPECTIVELY BETWEEN THE PERIPHERY OF THE PLUG AND THE WALL OF THE CUP ELECTRODE, AND BETWEEN THE ROD ELECTRODE AND THE WALL OF THE CENTRAL APERTURE IN THE PLUG.

Description

/N VEN TORS CHI/VG 'Koo/v PUN BY Cfu/v6-F C/mu Poo/v dem; 1%4/ H TT'OR/VE YS ELECTRIC DRY" CELLS Filed July 16, 1969 CHING-KOON PUN ETAL Nov. so, 19'7-1 United States Patent O 3,623,915 ELECTRIC DRY CELLS Ching-Kaon Pun and Ching-Chau Poon, both of P.0. Box 5538, Kowloon, Hong Kong Filed July 16, 1969, Ser. No. 842,274 Claims priority, application Great Britain, July 11, 1969, 35,369/ 69 Int. Cl. H01m 1 02 U.S. Cl. 136--133 7 Claims ABSTRACT F THE DISCLOSURE An electric dry cell having the open end of its cup electrode closed by a moulded plastics plug which is gripped around its periphery by the inturned end of the cup and has a central aperture embracing the rod electrode, annular spaces lled with sealing material being provided respectively between the periphery of the plug and the wall of the cup electrode, and between the rod electrode and the wall of the central aperture in the plug.

This invention relates to electric dry cells of the kind which include an outer cup-like electrode or can and an inner rod-shaped electrode positioned centrally and coaxially of the cup electrode, which cells are those hereinafter referred to as being of the kind described. The invention is particularly directed to improvements in the sealing arrangements at the mouth of the cup electrode or can, where a plug is normally provided whose primary purposes are to close the open end of the cup and to maintain the rod electrode in its desired position centrally of the cup.

According to the invention there is provided an electric dry cell of the kind described, having a plug made of electrically insulating plastics material mounted in the open end of the cup electrode to seal such open end, said plug being gripped around its periphery by the inturned rim of the cup electrode and having a central aperture whose wall embraces the outer end region of the rod electrode, a first afnnular enclosed space being provided between a peripheral face of the plug and the inside surface of the inturned rim of the cup electrode, and a second annular enclosed space being provided between a face of the central aperture of the plug and the wall of the rod electrode, both of such spaces being filled with sealing material.

Such arrangement provides a much more efficient seal between the plug and the electrodes than is the case in conventional cells in which the inturned rim of the cup surrounds the periphery of the plug, and the plug surrounds the rod electrode, without the interposition of any sealing material. The cup electrode may still of course be provided with a conventional outer insulating sheath of cardboard or plastics material and with a further outer metal casing if desired. The sealing material may be of any convenient kind such as wax, asphalt, liquid asphalt, monolithium chloride and resin, adhesive material or the like.

[Preferably the said peripheral face of the plug is formed with an annular face portion extending obliquely to the longitudinal axis of the cell and defining the inner wall of the said first annular enclosed space. The said annular face portion of the peripheral face of the plug is preferably of outwardly concave configuration.

'Preferably the said face of the central aperture of the plug is formed with an annular face portion extending obliquely to the longitudinal axis of the cell and defining the outer wall of the said second annular enclosed space.

The said second annular enclosed space may conveniently be partly defined by the underneath face of a contact cap 'mounted on the outer end of the rod electrode. The said contact cap may be of the kind which does not extend radially outwardly from the rod electrode to any great extent, in which case the said plug will also constitute the end closure of the cell, or the contact cap may extend outwardly as far as the periphery of the plug and thus itself provide such end closure; in the latter case the periphery of the contact cap may be connected in known fashion to (but of course insulated from) the rim of the cup electrode.

Preferably an annular groove or slot is provided in the outer surface of the plug near to its periphery for the reception of the inwardly turned rim of the cup. If the cup is provided with an outer metal sheath the last mentioned groove or slot may be enlarged for the reception of the inturned rim of such sheath.

The plug may conveniently be of internally domed configuration to provide more space for the contents of the cell, whilst its central aperture may be defined by an elongate sleeve embracing the rod electrode. Preferably the inner end of the said sleeve engages the outer end face of a depolarizer dolly of the cell, or an end cover plate of said dolly, and the said inner end of the sleeve is formed with a rnumber of circumferentially spaced cut-outs for air circulation within the cell.

In order that the invention may be more readily understood one embodiment of the same, together with a modification thereof, will now be described by way of example and Iwith reference to the accompanying drawings, in which:

|FIG. 1 is an axial cross-sectional view of an electric dry cell according to the invention;

|FIG. 2 is a similar view of the top part of the cell of FIG. 1, but to an enlarged scale; and

FIG. 3 is a View similar to that of FIG. 2 but showing a modification.

This embodiment of an electric dry cell according to the invention comprises an outer cup electrode in the form of a cylindrical open-ended vzinc can 1, and an inner rod electrode 2 made of carbon and positioned centrally and coaxially of the cup electrode.

The major part of the annular space between the rod electrode 2 and the cup electrode 1 is filled by a conventional depolarizer dolly 3, the annular gap between the outside surface of such dolly and the inside wall of the cup electrode being filled with electrolytic paste 4; the dolly 3 is preferably supported and located centrally and coaxially of the cup electrode, and thus held spaced from the wall of the can, by a cup-like spacing element 5 as described and claimed in our co-pending U.S. Application, Ser. No. 842,119, filed July 16, 1969. A base plate 6 forming part of the spacing element 5, or some other separate and known element, is provided to insulate the lower end of the rod electrode 2 and the underside of the dolly 3 from the floor of the cup electrode 1.

The open end of the cup electrode 1 is closed by a plug 7 formed of electrically insulating plastics material, such plug being of annular form with its central aperture surrounding and gripping the top end region of the rod electrode whilst its peripheral region is gripped by the inturned rim of the cup electrode.

Referring now particularly to FIG. 2 the central aper ture in the plug is dened by a sleeve 8 which depends from a generally flat body portion 9 of the plug, whilst at its periphery the plug is formed with a dependent annular skirt 10 so that the plug as a whole is of generally hollow configuration. A number of radial strengthening webs 11 extend between the central sleeve 8 of the plug and its peripheral skirt 10.

The plug 7 is formed at its periphery, around the upper and outer region of its skirt 10, with a somewhat concave oblique face 12 which faces upwardly and outwardly towards the inner wall of the inturned rim of the cup electrode 1. An annular space is thus defined between such oblique face 12 and the inner wall of the cup, and before the rim of the cup is spun into engagement with the plug this space is filled with a sealing material 13 such as wax, asphalt, liquid asphalt, monolithium chloride and resin, adhesive material or the like.

A further but inwardly and upwardly facing oblique face 14 is formed at the inner and upper region of the central sleeve 8 of the plug 7. The top end of the rod electrode 2, which the sleeve 8 surrounds, is provided with a metal contact cap 15 having an outwardly extending annular ange portion 16. An annular space is thus defined between the underneath surface of the flange 16, the wall of the rod electrode 2 and the annular oblique face 14 of the plug sleeve 8. Before the contact cap 15 is mounted on the rod electrode '2 such space is filled with sealing material 17 similar to that used at the periphery of the plug.

The lower end of the sleeve 8 of the plug 7 rests on a top cover plate 21 of the depolarizing dolly 3, and is formed with a number of circumferentially spaced cutouts 22 to increase air circulation within the cell. The dolly cover plate 21 serves to bring about an even transmission of pressure from the inturned rim of the cup electrode 1 to the dolly 3 via the webs 11 of the plug 7.

The contact cap 1S on the rod electrode 2 may if desired extend outwardly to the periphery of the plug 7 so as to form and end closure of the cell. The edge of the cap may then be incorporated into the seal between the plug and the rim of the cup electrode 1, whilst of course being insulated from the latter. Such insulation may be achieved in known manner by mounting a ring of insulating plastics or rubber material around the edge of the contact cap before the rim of the cup electrode is spun over. Alternatively, the end region of an insulating sheath provided on the cup electrode can be arranged to engage between the rim of the cup and the edge of the contact cap.

The rim of the cup electrode 1 is spun over into engagement with the top surface of the plug 7 and is received in an annular groove 18 formed in such plug surface near to its periphery. FIG. 3 shows a modification in which the cup electrode is provided with an insulating sheath 19 of cardboard or plastics materials and an outer tubular metal casing 20, and in this embodiment the groove 18 is enlarged for the reception of the inturned ends of the insulating sheath and outer metal casing.

The sealing effect between the plug 7 and the electrodes 1 and 2 can be further enhanced if, as in a preferred form of the invention, the outside diameter of the plug is made slightly greater than the inside diameter of the cup, whilst the diameter of the central aperture in the plug is made slightly smaller than the outside diameter of the rod electrode, so that a very tight engagement is provided between such parts; to achieve such engagement the plug will be formed of a somewhat resilient plastics material. Further, a thin layer of coagulating adhesive material may be provided between the periphery of the plug and the cup electrode and between the inside of the plug and the rod electrode so as to enhance the seal still further.

In another modification, which is not illustrated, thev conventional longitudinal seam in the outer metal casing may be omitted, and space thus saved therewithin, by

4 spinning the bottom end of such casing over a metal or plastics ring which will serve to hold the casing in its cylindrical shape. The bottom corner of the cup electrode may then be formed with a shallow annular indentation for the reception of the ring.

It will thus be seen that the invention provides a dry cell in which the seal between the plug for the mouth of the cell and the electrodes thereof is substantially improved as compared with known arrangements.

We claim:

1. An electric dry cell comprising an outer cup-like electrode, an inner rod-shaped electrode positioned centrally of the cup electrode, and a centrally apertured plug made of electrically insulating plastics material mounted in the open end of the cup electrode and sealingly associated with the respective electrodes, the rim of the cup electrode being turned inwardly over the edge of the plug, characterized in that the seal between the plug and the cup electrode is provided by an outwardly opening annular channel between the outer peripheral face of the plug and the inside wall of the cup electrode adjacent the rim of the latter, said channel being filled with sealing material, the seal between the plug and the rod electrode being provided by an outwardly opening annular channel on the inner peripheral face of the plug between the plug face and the surface of the rod electrode, said channel being `filled with sealing material, and a flanged contact cap on the end of the rod electrode, enclosing the said channel.

2. A cell as claimed in claim 1, wherein the outer peripheral face of the plug is formed with an annular face obliquely to the longitudinal axis of the cell, to define one wall of the said annular channel between the plug and the cup electrode.

3. A cell as claimed in claim 1, wherein the inner peripheral face of the plug is formed with a part-conical portion to define one wall of the said annular channel between the plug and the rod electrode.

4. A cell as claimed in claim 1, wherein the said contact cap only covers the outer end of the rod electrode and the inner one of said channels, the said plug constituting the end closure of the cell.

S. A cell as claimed in claim 1, wherein an annular groove is provided in the outer surface of the plug near to its periphery receiving the inwardly turned rim of the cup.

6. A cell as claimed in claim S, wherein the cup electrode is provided with an outer metal sheath whose inturned rim is also received in said annular groove.

7. A cell as claimed in claim l, wherein the said plug is of internally domed configuration.

References Cited UNITED STATES PATENTS 2,712,034 6/1955 Seavey et al. 136-133 2,766,316 lO/1956 Stevens et al. 136-133 FOREIGN PATENTS 574,951 l/l946 Great Britain 136-133 61,689 5/1955 France 136-133 (First addition of 1,029,283)

DONALD L. WALTON, Primary Examiner U.S. Cl. X.Rv 136-169 UNTTED STATES PATENT OFFICE CERTIFICATE 0F CORRECTIN Patent No 3.623.915 Dated Nov- 3o 1971 Ilfnvencods) CHING-KooN PUN et al y It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column l, line 7, "July ll, 1969" should read July 24, 1968 line 8, "35,369/69" should `read 35, 3569/68 Signed and sealed this 25th day of April 19Y2.

(SEAL Attest:

FEJDLJAPJD IYLFLETCEL-, JH. ROBERT GOTTSGHALK Attesting Officer Commissioner o' Patents