IMPROVEMENTS IN SECONDARY GALVANIC BATTERIES
Year: 1882

page_text: LETTERS PATENT to Herbert John Haddan, of Kensington, Middlesex, for an
Invention of "IMPROVEMENTS IN SECONDARY GALVANIC BATTERIES." A
communication from abroad by Doctor Emil Boettcher, of Leipzig, in the
Kingdom of Saxony.
PROVISIONAL SPECIFICATION left by the said Herbert John Haddan at
IN
the Office of the Commissioners of Patents on the 11th January 1882..
HERBERT JOHN HADDAN, of Kensington, Middlesex. IMPROVEMENTS
SECONDARY GALVANIC BATTERIES. A communication from abroad by Doctor
Emil Boettcher, of Leipzig, in the Kingdom of Saxony.
This Invention relates to secondary galvanic batteries or accumulators and
consists in the application of zine vitriol as exciting liquid and of zinc and oxide of
lead as electrodes, the action of these elements being as follows:-An electric
current from a dynamo-machine passing through a solution of pure sulphate of
zinc (one part of the salt to three parts of water) decomposes the said salt and
causes a deposit of zinc on a thin plate of pure zinc, the diluted sulphuric acid
(1 to 10) being not strong enough to attach pure zinc. The other pole is formed
by thin lead foil folded several times in order to augment the active surface, and
covered with a thick layer of pure litharge. The oxygen coming in contact with
the said lead foil produces a very thin layer of peroxide of lead. By closing the
galvanic element thus formed, the zinc previously deposited is again dissolved, and
thereby the sulphate of zinc produced, while the hydrogen reduces not only the
peroxide formed on the lead plate, but also a layer of the oxide of lead, thereby
forming metallic lead. If now the current from the dynamo-machine is again
passed through the element, a new deposit of zinc is formed on the zinc plate,
while on the opposite pole not only the previously reduced peroxide of lead, but
also the lead formed from the oxide is again oxidized into peroxide of lead. By a
few repetitions of this process the secondary galvanic element is completed and has
acquired high electro motive power.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Herbert John Haddan in the Great Seal Patent Office on the
11th July 1882.
HERBERT JOHN HADDAN, of Kensington, Middlesex. IMPROVEMENTS IN
SECONDARY GALVANIC BATTERIES. A communication from abroad by Doctor
Emil Boettcher, of Leipzig, Saxony. -
A solution of pure sulphate of zinc (1 part of sulphate to three parts of water) is
decomposed by a current from a dynamo electric machine, and thereby zinc
deposited on a cathode or plate of very thin sheet zinc. The liberated sulphuric
acid in the state of dilution employed (1 part of acid to 10 parts of water) does
not attack the pure zinc, as shown by experience. As anode I use thin lead foil
(about 0.05 millimetres) which has been previously prepared by folding it length-
wise from top to bottom in order to increase the active surface, dipping it into an
aqueous emulsion of pure litharge (lithargyrum laevigatum) prepared with the
above zinc solution, and coating it with a thick layer of the said emulsion.
The oxygen coming in contact with the anode or lead-plate forms on its surface
an exceedingly thin layer of peroxide.
By closing the galvanic element or cell formed as described the previously
deposited zinc is re-dissolved and the original sulphate of zinc produced, while the
hydrogen reduces into finely divided metallic lead not only the peroxide formed on
the lead-plate but also a zone or layer of the oxide of lead coating. By a new
regenerative current zinc is again deposited on the zinc-plate, while on the anode
the recently reduced lead is oxidized into peroxide of lead.
A few repetitions of the process (" forming" process) render the secondary
element ready for use. It has the high electro-motive force of 2.2 Daniells, but
can be already practically utilized after the first decomposition, with an electro-
motive force of only 0-5 Daniell. The strength of current stored in the cell can be
completely recovered.
Owing to the material employed and the application of very thin plates the
element or cell can be constructed very light and at a low cost.
CLAIM:
The electrolytical formation of secondary cells or elements from pure zinc-vitriol,
and also the general arrangement of the thin lead plates coated with oxide of lead
and placed opposite the zinc plates, whereby great electro-motive force and
considerable quantities of electricity are attainable by elements of small weight.
In witness whereof I the said Herbert John Haddan have hereunto set my
band and seal this Eleventh day of July A.D. 1882.