IMPROVEMENTS IN SECONDARY BATTERIES
Year: 1881

page_text: LETTERS PATENT to Desmond Gerald Fitz-Gerald, of Brixton, in the
County of Surrey, Electrician, for an Invention of "IMPROVEMENTS IN
SECONDARY BATTERIES."
PROVISIONAL SPECIFICATION left by the said Desmond Gerald Fitz-Gerald
at the Office of the Commissioners of Patents on the 14th December 1881.
DESMOND GERALD FITZ GERALD of Brixton in the County of Surrey Electrician.
"IMPROVEMENTS IN SECONDARY BATTERIES."
My Invention consists in the use of carbon in conjunction with lead or compounds
of lead, for the electrodes of secondary batteries. In carrying my Invention into
effect I construct plates of carbon with perforations grooves or recesses which are
filled with lead, preferably in a state of fine division or with any suitable compound
of lead. The pores of the carbon also are filled with the same material which in
this case more especially may advantageously be produced by the decomposition of
a salt or of an oxide of lead. Or I place the divided lead or the compound of lead
within a tube or vessel of carbon within which the compound of lead may in
certain cases be heated. Such carbon tube may be perforated either in the first
place or after certain operations have been performed upon its contents. Or I
employ the carbon in the form of fraginents which should be in direct contact with
each other at one or more points whilst the interstices between the fragments are
filled with lead in a state of division or with certain compounds of lead alone or in
admixture with other bodies. The carbon fragments may be placed within a tube
or vessel of carbon or of lead perforated as aforesaid. In certain cases such frag-
ments may be coated with lead by electrolytic deposition or otherwise.
When one side of a plate of carbon is intended to constitute an anode and the
opposite side a cathode I prefer to construct the carbon plate in a compound form
i. e., I cement 2 plates of carbon together in such manner as effectually to prevent
any electrolytic communication between the two sides of the compound plates.
Such compound plates are used to divide a trough into cells as is well understood.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Desmond Gerald Fitz Gerald in the Great Seal Patent Office
on the 14th June 1882.
DESMOND GERALD FITZ-GERALD of Brixton in the County of Surrey Electrician.
"IMPROVEMENTS IN SECONDARY BATTERIES."
This Invention relates to "Improvements in Secondary Batteries."
According to my Invention I use carbon in conjunctions with lead or compounds
of lead for the electrodes of secondary batteries.
In carrying my Invention into effect I employ the carbon in the form of fragments
which should be in direct contact with each other at one or more points whilst the
interstices between the fragments are filled with lead in a state of division or with
an oxide of lead such as red lead or plumbic peroxide or with an insoluble salt of
lead such as-the-sulphate.-The-carbon-fragments-may-with-advantage-be-in-the-
first place impregnated or coated with lead by immersing them in a solution of a
salt of that metal such as the acetate and subsequently reducing the metal either
by heating the prepared fragments without access of air or by electrolysis the
prepared fragments being in the latter case made the cathode in a suitable electrolyte
preferably a solution of the acetate or nitrate of lead with which a plate of lead is
used as anode.
In the construction of a cell or couple with the carbon fragments the latter are
divided into two portions each of which is in contact with a plate of carbon to
which a suitable terminal is attached by the use of a binding screw or by casting
on to the carbon plate a lug or piece of lead in which a connecting or terminal
wire is embedded. The two portions of carbon fragments are prevented from
coming into contact by the use of a diaphragm of felt, of porous earthenware, of
Paris plaster, or other suitable material.
In carrying this portion of my Invention into effect I prefer to employ boxes or
vessels of wood rendered waterproof by immersion in melted paraffin the interior
portions being further coated with a waterproofing substance such as marine glue.
These boxes or containing vessels have two of their dimensions very considerable
in comparison with the other dimensions so that when one side of the box is
removed the remaining portion has the form of a square tray. A plate or strip of
gas carbon of smaller dimensions that the bottom of this tray is laid flat upon the
latter and is made to project through the side of the tray sufficiently to establish a
contact. A layer of carbon fragments of such thickness as nearly to half fill the
tray is then laid upon the bottom and lead in a state of fine division or an oxide or
insoluble salt of the metal is sifted on to the carbon and shaken down into its
interstices the layer being subsequently subjected to a pressure sufficient to bring
the carbon fragments into good conductive contact with each other and with the
carbon contact piece. A plate of porous earthenware a sheet of felt or other suitable
material to constitute a diaphragm is then laid upon the compressed layer the edges
of the diaphragm being preferably cemented to the tray. Or a layer of Paris plaster
may be run on to the layer of carbon fragments the plaster being used in conjunction
with the felt or otherwise. Upon the diaphragm is then placed a second layer of
carbon fragments with the intersticial spaces filled with lead or a compound of
that metal exactly as in the previous case. The side of the box constituting a lid
or cover to the tray is then applied with sufficient pressure to bring the carbon
fragments into conductive contact. To secure a watertight joint strips of
caoutchouc may be employed and for the purpose of introducing the electrolyte a
glass tube may be cemented into the upper portion of the box or containing vessel.

page_text: The electrolyte may be dilute sulphuric acid in the proportion of one of acid to ten
or twelve of water.
Or the diaphragm may take the form of a porous jar the elements in this case
being preferably cylindrical.
Another mode in which I employ the carbon fragments in conjunction with finely
divided lead or an oxide or a salt of lead for the construction of electrodes is to
enclose the fragments within a tube or vessel of carbon or of lead such tube or
vessel being perforated with apertures which are filled or covered by a substance
such as Paris plaster, parchment paper or felt which prevents the escape of the
enclosed material.
When one side of an electrode of carbon perforated or otherwise and impregnated
or charged with lead or a compound of that metal is intended to constitute an
anode and the opposite side a cathode I prefer to construct the carbon plate in a
compound form i. e. I cement two plates of carbon together in such manner as
effectually to prevent any electrolytic communication between the two sides of the
compound plates. Such compound plates are used to divide a trough into cells as
is well understood.
I claim as my Invention to be secured by the herein before in part recited Letters
Patent-
1. The use of carbon in fragments alone or impregnated or coated with lead in
conjunction with lead in a state of fine division or an oxide or a salt of lead and
also with a plate of carbon by means of which contact with the carbon fragments
is obtained.
2. The use of the aforesaid mixture of carbon fragments with lead in a state of
fine division or an insoluble compound of lead in conjunction with a tube or vessel
of carbon or of lead perforated with apertures which are closed with or covered by
a porous material substantially as described.
3. The construction of compound plates of carbon for use in batteries having the
form of Cruikshanks trough substantially as described.
In witness whereof I the said Desmond Gerald Fitz-Gerald have hereunto
set my hand and seal this Fourteenth day of June in the year of our
Lord One thousand eight hundred and eighty two.
Witness
JOHN W. GRAY C. E.
Patent Agent
27 Southampton Bldgs
W.C.
DESMOND G. FI1Z-GERALD. (L.S.)