Improvements in the Manufacture of Electric Accumulators.
Year: 1897

page_text: Date of Application, 7th Aug., 1897-Accepted, 6th Nov., 1897
Improvements in the Manufacture of Electric Accumulators.
I, FEDERICO PESCETTO, Lieutenant-Colonel of Engineers, of Via Pastrengo
15, Turin in the Kingdom of Italy, do hereby declare the nature of this invention
and in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement:-
-
The present invention relates to improvements in the manufacture of electric
accumulators, and has specially as its object improvements in the preparation of
the plates, before putting the paste upon them, and in the preparation of the
active material. The first improvement has for its scope, the retention of the
active material and to assure contact with the plates; the second has for its scope
the augmentation of the reacting surface of the electrodes with the consequent
advantages of a notable augmentation in the capacity of the element, and of the
possibility of subjecting it to considerable range of charge and discharge. Finally
both improvements have as object the reduction (in the same conditions of capacity
and range) of the weight of the batteries in comparison with those of other systems,
rendering them in this manner specially apt for traction service.
The Figures 1 and 2 of the annexed drawings represent respectively a transverse
and a longitudinal section of a plate obtained by casting in the usual manner and
in part fashioned as hereinafter described. Figure 3 is a plan of the same.
The plates obtained by casting are fashioned by hand, with a tool or knife, held
obliquely on the border of the hole and in such a manner that the blade leans over
the sides of the hole, which is to the right of the operator, in this way jags A
are cut. The operation is made thrice and turning the plate each time 90° and
the same operatious are repeated on the opposite face of the plate.
It is evident that by modifying the plate by the above mentioned fashioning the
object is attained of retaining the active material without preventing the perfect
formation of the pastils.
In the minium and in the litharge which serve to form the pastils of active
material of the plates, is mixed a special substance in the proportion of 5% to
10% of the respective weight of the above mentioned oxides.
This substance is ulmate of ulmin (a well defined chemical substance) and it is
obtained by the known chemical means preferably as described in the Specification
of a patent granted to Lake No. 1309287; it must however be reduced to only
1.5 degrees of acidity at the maximum, and must be used at the consistency of
putty.
To this state it must if dry be reduced by mixing it with distilled water.
The mixture of the oxides of lead with the ulmate of ulmin must be as intimate
as possible and in order to facilitate this the same acidulated water can be employed
which is commonly used for the imparting of the active material.
The ulmate of ulmin which deposits in very small grains lends itself admirably
to render the active material of the plates porous, augmenting at the same time
the reacting surface. Besides this, (being sufficiently conductive) it improves to
a great degree the continuity of the electric contacts, so permitting the maximum

page_text: of charge and discharge, such as no other element will permit. The separating
action, which with other plates manifests itself in unpleasant manner, is in the
case of the present invention totally eliminated; if only one succeeds in obtaining
the ulmate in a compact paste of microscopic grains, it serves to cement the active
material in a satisfactory manner in the holes of the plates.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is:-
1. Plates for electrodes of electric accumulators, with the holes fashioned as
described around their borders as hercin set forth.
2. The employment of ulmate of ulmin in the minium and in the litharge, and
in general in the active material of electric accumulators, in the manner described.
Dated this 7th day of August 1897.
FEDERICO PESCETTO.