Improvements in the Mode of Filling Secondary Battery Plates.
Year: 1888

page_text: Date of Application, 31st May, 1888
Specification Accepted, 6th July, 1888
Improvements in the Mode of Filling Secondary Battery Plates.
We, HENRY GURNEY MORRIS, Engineer, and PEDRO GROTJAN SALOM, Chemist,
both of 209, South Third Street, in the City of Philadelphia, State of Pennsylvania,
one of the United States of America, do hereby declare the nature of our said
invention, and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :–
The object of our invention is to evenly distribute the active material of a secondary
battery plate upon the supporting plate, and to firmly and uniformly pack said material
in the interstices or cells of the plate.
This object we attain as fully described hereinafter, reference being had to the
accompanying drawings, in which-Figs. 1, 2, 3, 4, and 5, are sectional perspective
views illustrating the different steps of the process; and Fig. 6, is a sectional per-
spective view of a finished plate.
It is well understood that a secondary battery plate should have the active material
uniformly distributed, and of uniform density throughout, otherwise, the chemical
action at certain parts of the plate being greater than at others, owing to the currents
of electricity taking the line of least resistance, will cause the plate to buckle or warp,
and the active material to fall out.
In the present method of applying the paste to the grid or supporting frame, it is
customary to first put a quantity of the paste in the middle of the supporting frame
and then work it out to the edges, but in almost every instance the packing at the
centre of the plate is of greater density than at the periphery. To overcome this
objection and form a perfectly uniform plate, we proceed as follows:
Referring to Fig. 1 of the drawings, A, represents the supporting frame or grid,
which is placed upon a sheet, a, of metal or other suitable material, a frame, B, being
placed over the grid and adapted to fit snugly around the periphery of the same, said
frame being somewhat higher than the grid, and by preference, provided with a lip, c,
extending over the edge of said grid to a point adjacent to the first row of openings
therein. The active material, D, preferably in a powdered form, is then distributed
over the grid, filling the cells or interstices of the same, as shown in Fig. 1, after
which a scraper is passed over the frame, B, so as to remove all the superfluous
material, leaving a smooth and even surface, level with the top of the frame.

page_text: is
The frame is then removed, and a thin metal sheet, b, similar to the sheot, a,
placed upon the powdered material, as shown in Fig. 2, after which the grid is turned
over, so that the plate, b, is underneath and the plate, a, on top. The latter plate is
then removed, the frame, B, again placed upon the grid, and the powdered active
material dusted over the upper side of the latter, after which the scraper is passed over
the frame, B, to remove the surplus material, as shown in Fig. 3, the frame, B, being
then removed and the plate, a, replaced, as shown in Fig. 4. the active material being
now uniformly distributed to a certain depth above and below the grid, and in the
cells of the same.
The next step in the operation is to insert the grid, A, and plates, a, and b, with the
interposed active material, between the upper and lower dies, F, F, of a suitable press,
by which the active material is compressed into the cells of the grid, the quantity of
material previously applied having been properly gauged with reference to such
compression.
By this means the active material is uniformly distributed throughout the cells of
the grid and densely and uniformly packed therein.
In some instances, the active material may be placed upon one side only of the grid
prior to compression, but we prefer the above described method, as by it we obtain a
perfect plate of the nature herein before indicated.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner-the-same-is-to-be-performed,-we-declare that_what_we_
claim is ;-
1. The mode hereinbefore described of forming secondary battery plates, said mode
consisting in filling the cells or interstices of the grid with powdered active material,
placing a uniform layer of said active material on one or both sides of the grid, and
then compressing the surplus material into the cells of the grid.
2. The mode herein before described of filling a secondary battery plate, said mode
consisting in mounting the grid on a supporting plate, applying a retaining frame to
the top of the grid, placing the active material in the cells of the grid and piling it
above the same, removing the surplus material until it is level with the top of the
retaining frame, and then removing the latter and compressing the surplus imaterial
into the cells of the grid.
3. The mode hereinbefore described of filling a secondary battery plate, said mode
consisting in mounting the grid on a supporting plate, applying a retaining frame to
the top of the grid, filling the colls of the latter with active material, and piling the
latter above the same, removing the surplus material until it is level with the top of
the retaining frame, then reversing the grid and repeating such operations on the
other side of the same, and finally compressing the two layers of surplus material into
the cells of the grid.
Dated this 21st dor of No. 1000
DAY, DAVIES & HUNT,
321, High Holborn, London, W.C.,
Agents for the Applicants.