IMPROVEMENTS IN SECONDARY BATTERIES
Year: 1882

page_text: LETTERS PATENT to Ludwig Epstein of No 144 High Holborn in the County
of Middlesex for an invention of “IMPROVEMENTS IN SECONDARY BATTERIES
"
PROVISIONAL SPECIFICATION left by the said Ludwig Epstein at the Office
of the Commissioners of Patents on the 14th June 1882.
LUDWIG EPSTEIN of No 144 High Holborn in the County of Middlesex
"IMPROVEMENTS IN SECONDARY BATTERIES"
This Invention has for its object improvements in secondary batteries. Each
cell of my secondary battery consists of an outer vessel of wood or other material,
and a porous cell within it; between the exterior of the porous cell and the sides
of the outer vessel I place a spiral scroll of sheet lead of several convolutions.
Within the porous cell I place a similar scroll of a smaller diameter. These scrolls
form the electrodes of the cell. To charge the battery I prepare a saturat d
solution of permanganate of potash, and to this I add ten per cent of sulphuric acid
and ten per cent of methylated spirit. I form the battery by passing through it
the current from a dynamo electric machine or other source of electricity. After
the connections have been reversed a few times the battery is ready for use in the
ordinary manner.
According to another method I prepare my cell with a number of flat plates of
lead parallel to each other and packed with powdered charcoal between. I couple
together the alternate plates, charge the cell with the permanganate solution and
apply the current as before.
The passage of the current causes the metal of one set of plates to become
rapidly peroxidised and on the reversal of the current this peroxide is reduced to a
spongy metallic state whilst the other plates in turn are peroxidised.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Ludwig Epstein in the Great Seal Patent Office on the 14th December
1882,
LUDWIG EPSTEIN of No 144 High Holborn in the County of Middlesex,
"IMPROVEMENTS IN SECONDARY BATTERIES
"
This Invention has for its object improvements in secondary batteries.
In my secondary batteries I form electrodes from metallic lead by the aid of an
electric current and of permanganate of potash or other permanganate or of
permanganic acid or analogous oxidizing agents as per-iodic or pyrosulphuric salts
any percbloric salt or metallic per iodates or any other analogous oxidizing agent
which I cause to be present in the cell. By this means I am able to obtain a much
more rapid formation than is otherwise possible and more efficient active coatings
upon the plates than are obtained by other methods.
I sometimes aid the formation by the employment of methylated spirit or other
like spirit in the cell.
My secondary battery cells may be of various forms and dimensions.
I will describe first the construction of a cell of cylindrical form. A convenient
size is 6 inches in diameter and 10 inches in height interiorly, Glazed earthenware
or wood lined with marine glue will be found suitable.
I prepare also two electrodes of sheet lead. I use sheet lead weighing about
three pounds to the square foot. I take two pieces of this lead 3 to 4 feet long
and 10 inches broad and lay one over the other with a water cushion of like
dimensions between. I roll altogether into a scroll of a size to enter the cell I
then let out the water and withdraw the cushion leaving the two electrodes
separated throughout by a space of uniform width.
Each electrode should have a strip of lead extending from it to form the
connection with the next cell. I charge the cell with a saturated solution of
permanganate of potash to which I have added at least ten per cent of commercial
sulphuric acid and ten per cent of methylated spirit.
The cells are then coupled together and connected with a dynamo-electric
machine or other source of electricity as is usual in forming secondary batteries.
The current should during the forming process be reversed at shorter intervals
than is usual as the presence of the permanganate and spirit hastens the operation.
If the current be suitable the appearance of gas in the cells in considerable
quantity indicates when the current should be reversed, the reversal may be made
at once or the battery may first be disconnected from the dynamo machine and its
circuit closed in order that it may discharge. Then it is reconnected with the
dynamo machine and the current passed in the reverse direction and so on. A
short time under this treatment will suffice to impart to the battery a considerable
storage capacity.
It is not necessary that methylated spirit and permanganate should be used
together but the addition of spirit is advantageous.
Sometimes I form a rectangular battery cell. In this case a suitable size for the
cell for a battery to be used with incandescent lamps is say 18 inches long by
6 inches wide and 10 inches high I make the vessel of wood and line it with
sheet lead. The lining in conjunction with an intermediate or partition plate or
plates attached to it forms one of the electrodes. The other electrode is a plate
doubled upon itself and so placed within the vessel as not to come into contact
with the lining or with the plate or plates attached thereto but so that all its
surfaces may face surfaces of the lining electrode, leaving a space of nearly uniform

page_text: width between the adjacent surfaces to receive the liquid with which the cell is
charged. I employ the same liquid in this cell as in that previously described. I
sometimes further accelerate the process of formation by passing into the cell
whilst exposed to the current the vapour of permanganic acid which I obtain by
the distillation of powdered permanganate of potash with commercial sulphuric
acid diluted with water.
Where the object is to store a large quantity of electricity the cell may be made
large enough to contain electrodes exposing many alternate positive and negative
surfaces in the manner described.
Having thus described the nature of my said Invention and the manner of
performing the same I would have it understood that I claim -
First. The employment of permanganate of potash or other permanganate or of
permanganic acid or of other analogous oxidizing agent in the manufacture of
secondary batteries substantially as described.
Second. The construction of secondary batteries substantially as described.
In witness whereof I the said Ludwig Epstein have hereunto set my hand
and seal this Twelth [sic] day of December in the year of our Lord One
thousand eight hundred and eighty two.
L EPSTEIN. (L.S.)