US1331762A - Dry cell - Google Patents

Description

C. W. HAZELET'T.

- DRY CELL. APPLICATION FILED MAY 9.1919.

Patented Feb. 24, 1920.

A TTORNE UNITED STATES PATENT OFFICE.

CLARENCE W. HAZELETT, OF LAKEWOOD, OHIO, ASSIGN'OR TO NATIONAL CARBON i I COMPANY,INC., A CORPORATION OF NEW YORK.

. DRY CELL.

To all whom it may concern..-

Be it known that I, CLARENCE W. HAZE- LETT, a citizen of the United States, residing at Lakewood, in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Dry Cells, of which the following is a full, clear, and exact description.

This invention relates to dry cells.

It is well known that dry cells are made from zinc cans which contain an electrolyte mix tamped around a central carbon electrode with a paper or other bibulous lining between themix and the can. When paper is used as a bibulous lining it is the usual custom to use a lining that is considerably longer than the compacted mass of mix in the can, so that it may be folded over or otherwise crumpled into position on top of the mix. sand is usually added on top of the folded over portion of the lining, and then a seal 7 as molten pitch, is poured on top of the sand until it is substantially level with the top of the can. With dry cells made as specified it is found that there is considerable trouble experienced through the corrosion of the zinc immediately below the layer of sand. The corrosion at this point is much more rapid than in other portions of the cell, and frequently the top portion of the zinc will be entirely separated from the lower portion before the useful life of the cell would otherwise have terminated.

It has been found that the excessive corrosion of the zinc near the top is caused by the greater concentration of electrolyte in this neighborhood, due to the increased amount of electrolyte in the crumpled-over portion'of the lining. During the action of the cell the surface of the paper lining adjacent the zinc is depleted of electrolyte and this must be supplied by the diffusion of other electrolyte from the interior portion of the lining and from the adjacent mix. Since there is a greater mass of the paper lining at the top due to the crumpled-over portion, the electrolyte will diffuse more rap-idly to raise the concentration of the electrolyte in the surface adjacent the zinc, than it will in the lower portions of the lining where there is only one thickness of lining. Consequently there results a higher concentration of electrolyte adjacent the surface of the zinc where the lining is folded Specification of Letters Patent.

To complete the cell a layer of Patented Feb. 24, 1920.

Application filed May 9, 1919. Serial No. 295,988.

over the top of the mix. The difference in concentration between the top of the zinc and the other portions causes continual electrolytic action that eventually dissolves away the zinc at the top.

It has also been found that the excessive corrosion near the top is caused in part by the good conducting path between the electrode and-the zinc furnished by the bentover portion of the lining which of course is more or less saturated with good conducting electrolyte. In applying the paper lining to zinc cans it is usual to use such length of paper or pulpboard'that the ends overlap in a vertical direction. This has been found to cause corrosion of the zinc adjacent to this overlapping portion, which is due to theexcess of electrolyte retained by the double thickness of lining, for substantially the same reason as previously described in connection with the bent-over portion at the top of the mix. My invention aims to overcome these disadvantages and the manner in which the result is accomplished will now be described, reference being had to the drawings in which:

Figure 1 is a view of a sheet of paper containing my improvement.

Fig. 2 is a section of a battery can wit-h the lining in position.

Fig. 8 is a section taken on the lines AA of Fig. 1, a portion only of the lining being shown.

Fig. 4 is a view of a dry cell involving my improvement.

Referring to the drawings, I take a sheet of pulp or other form of paper board 1 and cut or saturate the topportion 3 and at least one side portion 2 with some material impervious to electrolyte and moisture, preferably one that is a non-conductor of electricity. Various materials may be used, but satisfactory ones are paraflin, tar and petroleum or other suitable oils.

The oils will be particularly serviceable where it is desired to saturate the edges of the lining instead of applying an outside coating. However, by using such coating materials'as paraffin and tar in hot condition, the lining edges may be saturated therewithin the same way as when oils are used. In Fig. 3 the coating 2 is shown greatly exaggerated in thickness in relation to the lining 1. It will be understood that the top portion of the lining 3 will be surrounded or saturated With the insulating material 4 in the same way as the edge portion 2.

After the linings are coated or impreg nated in the manner specified, they are rolled up and placed inside the zinc can 5 with the edge portion 3 at the top of the can and the edge 2 overlapping the edge 6, the edge 6 being preferably located adjacent the zinc.

The'inix 7 istampeld inside the lining 1 in any Way, and the saturated orcoated edge ishent over the top of the mix as shown in, Fig. 4E. The layer of sand 8 may be then added and the pitch or other seal 9 poured on ,topof the sand to complete the cell 7 A jacket is usually added to the outsideof the zinc can, but this forms no partof the invention and it is not shown on the drawings. I With this construction it Will be found that the corrosion adjacent the pitch seal is no more energetic than in any other portion of the can. Also the corrosion adjacent to theoverlapped portions 2 and 5 is the same as at any other point on the zinc. Consequently by the treatment of thebibulous lining in the Way specified, the life of the cell is very materially increased.

Having described my invention, 'What I claim, is h 1. In dry cells, a bibulous lining having a coating of impervious insulating material adjacent-one edge.

2. In dry cells, a bibulous lining having a coatingor impervious material on both sides adjacent to one edge andon said edge. 3. In dry cells, a bibulous lining having a portion thereof adjacent one edge impre nated With insulating material impervious to electrolyte or moisture. r Y

4. In dry cells, a container electrode having an electrolyte mix therein, an electrode in said mix, a bibulous lining around the mix with the side edges overlapping each other, and insulating waterproof material in one of said qvrh ping edges.

5. In dry ce ls, a container electrode having an electrolyte mix therein, central electrode in said mix, a bibulous lining around the mix, said lining having the top edge folded over the top of the mix and Waterproof and insulatingmateiial in the overlapping ortion or said lining. I

6. In dry cells, a container electrode having an electrolyte inix therein, a second electrode in said mix, bibulous lining around the mix with the side edges overlappin ea h other and with the top edge folded over the mix, and Water-proof and insulating inaterial in one of said overlapping edges and in said folded over edge, H

In testimony whereof, I hereunto aflix my signature.

W. HAZELETT.

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