US2648718A - Anode for primary galvanic cell - Google Patents

Description

Aug. 11, 1953 I R. c. SUNDEEN 2,643,718

ANODE FOR PRIMARY GALVANIC CELL Filed Feb. 23, 1950 INVENTOR ROY C. SUNDEEN A'TTORNEY Patented Aug. 11, 1953 ANODE FOR PRIMARY GALVANIO CELL Roy Carl Sundeen, Lakewood, Ohio, assignor to Union Carbide and Carbon Corporation, a corporation of New York Application February 23, 1950, Serial No. 145,723

4 Claims.

This invention relates to primary galvanic cells and refers more particularly to the manufacture of metal anodes for such cells.

The conventional cylindrical primary galvanic cell, the dry cell, of commerce comprises a zinc anode which serves also as the container of the cell. since the zinc anode is consumed during use of the cell, this type of construction is undesirable from many standpoints. For instance an excess of zinc over that required by the cell must be provided for the purpose of containing the non-consumable elements of the cell. Also sufiicient zinc must be provided to prevent leakage of liquid from the cell.

It has long been recognized that the use of a consumable electrode as a cell container is something less than ideal and from time to time suggestions have been advanced for ways of avoiding such construction. One of such suggestions is that the anode be placed inside the cell and that a non-corrodible container be employed. For instance, U. S. Patent 1,267,349 suggests that the anode be made of sheets of zinc assembled so as to form an X-shaped member which could be placed internally of the cell. However, by reason of manufacturing difficulties the suggested construction proved less economical and less practical than the conventional construction. Furthermore the anodes so made have been unsatisfactory by reason of mechanical weakness or a tendency to excessive local corrosion or both and the suggestion has come to naught as have other similar suggestions.

It is the principal object of this invention to provide an improved method of making a metal anode for rimary galvanic cells which anode is to be placed internally of the cell. Another object of the invention is a unitary anode for primary galvanic cells.

The invention by means of which these objects are attained comprises a method of forming a unitary anode from a sheet of metal by a series of cutting and bending operations explained in detail below and also includes the anode so formed, which anode comprises a plurality (preferably four) of radially disposed vanes connected by a yoke having a fiat area for terminal connection.

In the accompanying drawing:

Fig. 1 is a diagrammatic representation of a sheet of metal from which a plurality of anodes is to be formed;

Fig. 2 is a view of an anode blank cut from the sheet of Fig. 1;

Fig. 3 is a view of the blank of Fig. 2 after a bending operation;

Fig. 4 is an elevational view of a completed anode part being broken-away;

Fig. 5 is a perspective view of a completed anode; and

Fig. 6 is a horizontal sectional view of an anode according to the invention provided with a bibulous wrapper.

In accordance with this invention a unitary metal anode may be prepared from a sheet or strip of metal of desired thickness by cutting a blank comprising a plurality of plates joined together by a yoke which also spaces the plates apart from each other. By a series of bending operations an anode having a plurality of substantially uniformly spaced radial vanes connected by the yoke which also provides a, site for terminal connection to the anodes may be prepared. For example, the blank may be bent in the yoke about axes perpendicular to the longitudinal axes of the plates to bring the plates into proximity to each other and about the longitudinal axes of the yoke or plates so as to V the plates, thus providing radial vanes. Although the yoke may be bent about its longitudinal axis over its entire length, this is not necessary'and in general it is preferred not to bend the central part of the yoke.

Referring to the drawing by way of illustration, a plurality of blanks B are cut, suitably by a repetitive stamping operation from a sheet S of metal of suitable thickness. Each of the blanks B has a pair of plates II), II spaced apart from each other but connected by a yoke section I2. The plates I0, II are bent about the lines a-a and a'a' (Fig. 2) in the direction of the arrows to form vs (Fig. 3) but the central portion of the yoke I2 is preferably not bent in this operation. The plates I0, I I having been bent into V-shape, the blank B is now bent in the yoke about the lines bb, b'b' (Fig. 3) in the direction of the arrows to bring the apices of the Vd plates I0, I I into proximity to each other as shown in Fig. 4.

By this procedure a metal 'anode having a plurality of vanes and a substantially X-shaped cross section is formed in one piece from rolled sheet metal. By bending the yoke I2 as shown in Fig. 4 a flat section I3 is formed which serves as a terminal for the anode. By bending the plates I0, II substantially the vanes of the finished anode are uniformly, radially spaced apart from each other, making for uniform consumption of metal during use of a primary galvanic cell in which the anode is employed.

In accordance with conventional practice the active surfaces of the anode are enveloped by a bibulous separator or wrapper M of paper or textile or other conventional material (Fig. 6) which is insoluble in electrolyte, the surface of the wrapper next the anode being conventional starch paste or paste substitute. All surfaces of the anode which Would otherwise come into contact with the depolarizer mix of a cell should be covered by such wrapper. The wrapper may be provided at any convenient time during the formation of the anode and preferably should be so applied that there is no seam at the bottom edges of the anode.

The operations of the method of the invention are simple and lend themselves admirably to the continuous manufacture of anodes and may be performed by machines.

Since the anode produced by the method of the invention is one piece of metal, its performance in a cell is far superior to that of anodes of similar design but made up of several pieces; there are no mechanical joints or solder-ed or welded connections and consequently no discontinuities which tend to cause mechanical weakness and excessive localized corrosion. Further, since it is possible to make the plates I'll, II only long enough to be completely covered by depolarizer mix in a cell, the only metal unusable electrochemically is that in the yoke 12. This results not only in a saving of anode metal but also tends to minimize the difficulties caused by residual quantities of anode metal in contact with mix after the cell has delivered its normal service.

Oridinarily anodes for primary galvanic cells are composed of zinc. The method of the invention is especially Well suited to the manufacture of zinc anodes because of the workability of zinc, but it is equally adapted to use in making anodes of any desired metal or alloy.

Although for purposes of illustration the invention has been described with particular reference to the fabrication of an anode having four vanes substantially 90 apart, it Will be apparent to those skilled in the art that its principles are not limited solely to the manufacture of that particular form of anode. Furthermore the individual bending steps of the method of the invention need not necessarily be performed in any particular order.

I claim:

1. A method of making a metal anode for a primary galvanic cell which comprises preparing a unitary blank comprising a plurality of plates spaced apart from each other and connected by a yoke and bending said blank in said yoke about axes perpendicular to th longitudinal axes of said plates and about the longitudinal axis of said yoke thus providing a plurality of substantially uniformly spaced radial vanes connected by said yoke.

2. A method of making a metal anode for a primary galvanic cell which comprises preparing a unitary blank comprising a pair of plates spaced longitudinally apart from each other and connected by a yoke; bending said plates along their longitudinal axes, thus forming each of said plates into a V; and bending said blank in said yoke so as to bring the apices of said Vs into close proximity.

3. A method of making a metal anode for a primary galvanic cell which comprises preparing a unitary blank comprising a pair of plates spaced longitudinally apart from each other and connected by a yoke; bending said plates along their longitudinal axes about then forming each of said plates into a V; and bending said blank in said yoke so as to bring the apices of said Vs into close proximity.

4. A method of making a metal anode for a primary galvanic cell which comprises preparing a unitary blank comprising a pair of plates spaced longitudinally apart from each other and con nected centrally of their longitudinal axes a yoke; bending said plates along their longitudinal axes about 90 thus forming each of said plates into a V; and bending said blank in said yoke so as to bring the apices of said Vs into close proximity and substantially parallel to each other.

ROY CARL SUNDEEN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 368,608 Peyrusson Aug. 23, 1387 1,196,611 Tassin Aug. 29, 1916 1,266,166 Sangers :May 14, 1918 1,267,349 Smith May 21, 1918 1,631,568 Yngve June 7, 1927 2,212,054 Spicer Aug. 20, 1940 2,250,233 Parkington July 22, 1941

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