US724856A - Secondary-battery electrode. - Google Patents

Description

No. 724,856. PATENTED' APR, 7, 1903.

J. HAHMANN. SECONDARY BATTERY ELECTRODE.

APPLICATION FILED JULY 19, 1902. no MODEL] q/vi Bunsen mz NORRIS PETERS co. wno'roumouwunmumm u. c.

UNITED STATES- PATENT OFFICE.

JOSEF HAHMANN, OF BERLIN, GERMANY.

SECONDARY-BATTERY ELECTRODE.

s'Pno'IricATIon forming part of Letters Patent No. 724,856, dated April 7, 1903.

Application filed July 19, 1902. Serial No. 116,157. (No model.)

To all whom it may concern:

Be it known that I, J OSEF HAHMANN,.3. subject of the Emperor of Germany, residing at Waldstrasse 18, city of Berlin, Prussia, Empire of Germany, have invented certain new and useful Improvements in Secondary-Bate tery Electrodes, of which the following is a specification.

For secondary batteries I have produced a thin, light, and durable holder for the active material, and inthe claim I will point out the precise improvement.

In the accompanying drawings, Figure 1 shows in perspective the reticulated plate which forms the basin or base-frameofmy improved electrode. Fig. 2isa cross-section of the same. Fig. 3 shows the reticulated cover-plate for the basin. Fig. 4 is a crosssection of the same. Fig. 5shows in enlarged detail the corner part of the reticu'lated bottom base-frame. Fig. 6 shows enlarged a por-' tion of the reticulated bottom base-frame, its reticulated cover-frame, and the active material in the closure formed by the basin and the cover. Fig. 7 shows the corner of the base-fra me and the cast bottom strands without the frame-lip and in about the relative proportions of the mesh formed by the strands.

An oblong square frame 1 is molded'or cast with a reticulated bottom surface or back 2 on one side, leaving the other side of the frame open or uncovered. This reticulated bottom surface is comparatively thin and is strengthened and stiffened by intermediate bars 3, dividing the thin bottom into compartments. The reticulated thin bottom or back 2 covers the area within the frame-border, and the crossed strands forming said screen -surface are molded or cast with the frame and with the intermediate cross-bars, so as to form a bottom screen facing to the frame. The border of the base-framev stands above this screen-bottom and forms a sort of basin within the frame. The cross-bars 3 are flush with the border of the frame, as seen in Figs. 2' and 5, and divide the basin and its reticu-' lated bottom or back into squares to support the bottom. Into the basin-closure formed by this frame and the reticulated bottom the active material is packed and retained therein by the reticulated cover-plate 4, the border inner wall.

of which matchesor registers with the border of the base-frame and isfastened to the latter, preferably by soldering. This cover plate tis as thin as the reticulated bottom jecting from the inner wall edges of the base-.

frame flush with the back surface of the plate, as in Figs. 2 and 6, so that the lip 5 and the screen-strands are on a plane with the face of the plate, and the lip will thereby serve to hold the active material in packing it around and against the inner walls of the base frame, as in Fig. 6. The border of thecover-p1ate4 is wide enough to extend or overhang the inner wall of the base-plate to form a lip 6all around this wall corresponding with the lip 5 all around the base-frame, and thereby hold. the active material Within the base-frame all around its I prefer to make the screen-forming strands square in cross-section, so that they will form symmetrical interstices, give greater rigidity to the frame and locks for the active mass, which will be pressed in the bolt tom interstices. The active material in the form of paste is packed in the base-frame upon its reticulated bottom or back and smoothed off and'the cover-plate is placed on the open side of the base-frame, and the two border-frames are then soldered together, leaving the interstices of the cover-plate partially unfilled for the better circulation of the electrolyte fluid in the battery-cell. The reticulated bottom of strands crossing each other 'con'nect'the edges of the cross-bars and the frame-border, and the cover-plate with its crossed strands closes the base-frame over its cross-bars and its reticulated bottom and holds the active material intact and gives an efficient action to the electrode.

The base-plate, with its reticulated bottom and cross-bars, and the reticulated thin coverplate are molded or cast of a'nalloy of lead and antimony and form the current-collector in a way well understood in the art. As the electrode is used in the ordinary way and connected in the battery-cell by positive and negative wires with the battery-poles in the usual way, an illustration of such use is deemed unnecessary.

I have shown and prefer to mold or cast the 5 base-plate with the cross-bars, because the thin reticulated cover-plate can be soldered to them, and thereby prevent the possible bulging of the cover-plate, as in Fig. 6. I prefer to make the screen-strands compara- Io tively fine and the mesh about an eighth of an inch. With a cover-plate of fine strands the cross-bars are important to give the mesh the required stiifness and strength, and for this purpose the cross-bars are wide and divide the mesh into squares. Were it not for dividing the bottom mesh of fine strands by the cross-bars they would be without support and liable to break away from the borderframe, so that it is the molding of the fine mesh of the base-frame into compartments and the cover into squares by the cross-bars that allows the grid mesh to be formed of fine strands, which gives the advantage of increased cnrrent-collecting surface. Looking at Fig. 1 it will be noted that the division of the bottom of the basin into compartments renders it possible to make the back of the frame of a fine light mesh, because the crossbars form a frame-closure for each compartment, giving its bottom the required strength with lightness.

I claim- An electrode for secondary batteries consisting of a base-frame having a continuous lip on its inner wall flush with one of its faces, a back of strands connecting the continuous lip, and cross-bars flush with both sides of the frame connecting the back strands and dividing the back into compartments, the mesh bottom of each compartment bound and braced by the cross-bars, and a cover formed of a border, cross-bars and a mesh of fine strands between the bars and providing a. lip overhanging the base-frame lip.

In testimony whereof I affix my signature in presence of two witnesses.

JOSEF HAHMANN.

Witnesses:

A. E. H. JOHNSON, II. L. FRANC.

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