IMPROVEMENTS IN ELECTRICAL STORAGE BATTERIES
Year: 1882

page_text: LETTERS PATENT to Edward Frankland F.R.S. of Reigate Hill in the County
of Surrey Professor of Chemistry for an Invention of "IMPROVEMENTS IN
ELECTRICAL STORAGE BATTERIES,"
PROVISIONAL SPECIFICATION left by the said Edward Frankland at the
Office of the Commissioners of Patents on the 9th September 1882.
EDWARD FRANKLAND F.RS of Reigate Hill in the County of Surrey Professor
of Chemistry "IMPROVEMENTS IN ELECTRICAL STORAGE BATTERIES."
This Invention relates to the construction of the plates of Storage Batteries.
These plates are commonly made of lead or an alloy of lead and antimony or
sometimes of Carbon and they are then coated with an oxide of lead or an insoluble
Salt of Lead, the coating being retained in its place by felt or other textile fabric
(Faure) To avoid the use of a very perishable substance like felt, these plates
have been perforated either by casting or boring (Sellon & Volkmar) and spongy
lead has been inserted into holes leaving the rest of the surface of the plate bare.
This arrangement is more permanent than that of Faure but the plates of a
given size are less active because a considerable area of their surfaces is uncovered
by spongy lead, oxide of lead, or other lead compound.
Now my Invention consists firstly in hardening oxide of lead upon the metallic
or other plates of Storage Batteries whether perforated or not and either on the
whole surface of the plate or in the perforations only so as to cause it to attach
itself firmly to the surface of the plate without the use of felt or other similar
retaining fabric, and secondly, where perforated plates are used in piercing the
coating material with holes through the perforations of the plates so as to establish
numerous liquid connections between the two sides of the plate and thus promote
a more free circulation of the electrolyte.
In carrying out this my Invention I employ by preference Minium or red lead
as the coating material but any other oxide of lead, except the peroxide, will answer
the purpose nearly as well I make the minium into a paste with water or dilute
sulphuric acid and I spread this paste over the surface of the plate at the same
71

page_text: time filling up the holes if the plate be perforated and piercing through the coating
material in these holes with a brad-awl or other suitable instrument I then dry
the coating on the plate either spontaneously or at a steam heat. In this condition
the coating is loose and friable and if the plate be immersed in a liquid the coating
immediately falls off.
To prevent this I now lightly brush over the coating of the plate with a liquid
or material which will have a hardening effect upon the coating or filling such as
dilute sulphuric acid and again dry at a steam heat. I repeat this process once,
or it may be repeated oftener; but I find that two applications of the sulphuric
acid each followed by steam heat are sufficient to render the coating hard and to
attach it so firmly to the plate as to prevent its removal when used in a storage
battery:
The plates so prepared take a high charge and their coating becomes harder by
use. They can be fixed in the battery very close to each other without risk of
short circuiting.
The sulphuric acid may be replaced by other acids which form insoluble or
sparingly soluble salts of lead. Dilute hydrochloric acid and moderately strong
solution of oxalic acid give fairly good results but I prefer to use dilute sulphuric
acid.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Edward Frankland in the Great Seal Patent Office on the
8th March 1883.
EDWARD FRANKLAND F R. S. of Reigate Hill in the County of Surrey Professor
of Chemistry " IMPROVEMENTS IN ELECTRICAL STORAGE BATTERIES "
My Invention relates to the construction of the plates constituting the elements
of electrical storage batteries.
These plates are commonly made of lead or an alloy of lead and antimony or
sometimes of carbon and they are then coated with an oxide of lead or an insoluble
salt of lead the coating being retained in its place by felt or other fabric as in the
Faure Battery. To avoid the use of a very perishable substance like felt these
plates have been perforated either by casting or boring as in the Sellon and
Volckmar battery and spongy lead has been inserted into holes leaving the rest of
the surface of the plate bare. This arrangement is more permanent than that of
Faure but the plates of a given size are less active because a considerable area of
their surfaces is uncovered by spongy lead oxide of lead or other lead compound.
Now my Invention consists in hardening oxide of lead upon the metallic or other
plates of electric storage batteries whether perforated or not and either on the
whole surface of the plate or in perforations only or otherwise so as to cause it to
attach itself firmly to the plate without the use of felt or other similar retaining
fabric and where perforated plates are used My Invention also consists in piercing
the coating material with holes through the perforations of the plates so as to
establish numerous liquid connections between the two sides of the plate and thus
promote a more free circulation of the electrolyte. The hardened oxide of lead may
if desired be used without a metallic or other supporting plate.
In carrying my Invention into effect I employ by preference minium or red lead
as the raw coating material but any other oxide of lead except the peroxide will
answer the purpose nearly as well and I harden this minium or oxide of lead before
the plate is used either as a positive or negative plate in the storage battery by
applying to it or mixing with it sulphuric acid, phosphoric acid, hydrochloric acid,
or other acid, which forms an insoluble or sparingly soluble salt of lead, the acid
used being either diluted with or dissolved in a suitable quantity of water and I
employ by preference sulphuric acid.
And in order that the said Invention may be fully understood I shall now
proceed more particularly to describe the different modes in which it may be
carried out.
1. In applying the coating to metallic, graphite, or carbon, plates (whether per-
forated or corrugated or embossed or not) or to metallic gauzes or frames I
sometimes make the minium or oxide of lead iuto a paste with water and I spread
this paste over the surface of the plate to the required thickness at the same time
filling up the holes if the plate be perforated and piercing through the coating and
material in these holes with a bradawl or other similar instrument. I then allow the
coating to dry either spontaneously or at a gentle heat. In this condition the
coating is loose and friable and if the plate were in this condition immersed in a
liquid the coating would immediately fall off.
To prevent this I lightly brush over the coating of the plate with a mixture of
one part by measure of concentrated sulphuric acid and nine parts by measure of
water or I moisten the coating with this mixture by means of a spray producer.
The plate is then allowed to dry either spontaneously or at a gentle heat and this
process is to be repeated once or oftener if necessary but I find that two applications

page_text: of the dilute sulphuric acid are generally sufficient to render the coating hard and
to attach it so firmly to the plate as to prevent its falling off when used in a storage
battery but I prefer to first place the coated plate for about 12 hours or more in
a bath of sulphuric acid diluted with nine times its volume of water.
2. Another, and preferable, mode of making the hardening mixture and applying
it to metallic or graphite or carbon plates whether perforated or corrugated or
embossed or not or to metallic gauzes or frames is the following. I add to the
minium or other oxide of lead a sufficient quantity of a mixture of one volume of
concentrated sulphuric acid and two volumes of water to form a thin paste and I
then spread by means of a trowel or spatula this paste upon the plate to the
required thickness so as also to fill up any perforations corrugations or interestices
if there be any and I then pierce holes through the composition with a bradawl as
hereinbefore described. After the coating has been thus applied I allow it to dry
either spontaneously or at a gentle heat and I then pour upon each side of it so as
to thoroughly saturate it sulphuric acid diluted with six times its volume of
water and afterwards immerse it in a bath of dilute sulphuric acid as hereinbefore
described.
3. Another mode of using the hardening mixture consists in casting it upon in
or around any suitable metallic graphite carbon or gauze plate. For this purpose
I make a suitable mould preferably of wood or plaster of Paris in the centre of
which I place the plate or gauze and then pour in the requisite quantity of a
sufficiently fluid hardening mixture composed of minium or other suitable oxide of
lead and sulphuric acid diluted with thrice its bulk of water as herein before
described. The casting is to be allowed to remain in the mould until the compo-
sition has become sufficiently hard which will be the case in from two to three
hours. After removing it from the mould I allow the plate to dry either
spontaneously or at a gentle heat. I afterwards saturate it with sulphuric acid
previously diluted with six times its volume of water and then immerse it in a
bath of dilute sulphuric acid for twelve hours or more as hereinbefore described.
It is then ready for mounting in the cell of a storage battery. These plates may be
pierced with holes as herein before described but it is best to perform this operation
before the plate gets too hard in the mould. These plates so cast in the moulds have
true and parallel surfaces and can therefore be placed very close to each other in
the storage cell which is of great advantage. But it is obvious that plates or blocks
of cylindrical or other shape can be manufactured by this method.
4. Another mode of using the hardening mixture especially adapted for plates of
curved or zigzag form consists in mixing the minium or other suitable oxide of lead
with sufficient sulphuric acid diluted with twice its volume of water to form a thick
cream and then dipping the plates into this mixture. The coating thus imparted
to the plate is allowed to dry as herein before described and the dipping operation
and subsequent drying may be repeated if necessary until the coating has attained
a sufficient thickness. Finally the plates should be saturated with dilute sulphuric
acid and immersed for 12 hours or more in a bath of the same as herein before
described.
5. Another mode of applying the hardening mixture to the construction of the
plates of storage batteries is the following. I make the hardening mixture of the
consistency of thick cream as herein before described and I then cast it in moulds
as hereinbefore described but without any carbon graphite metallic or other basis
or nucleus using the hardening mixture either alone or mixed with plumbago
powdered coke or filings or borings of lead or other suitable metal or alloy in order
to give the plate greater conductivity. The plates may be perforated in the moulds
as hereinbefore described and after being thoroughly dried either spontaneously or
at a gentle heat they should be saturated once at least with dilute sulphuric acid
and then immersed in a bath of the same as herein before described If the plates
have been made with the hardening material alone that is to say without any
admixture of plumbago powdered coke or filings or borings of lead or other
suitable metal I give to them the necessary conductivity by transforming the

page_text: material composing the plate which is to be negative in the storage cell into spongy
lead and the plate which is destined to be positive in the storage cell into peroxide
of lead by tying or otherwise temporarily attaching them to flat plates of lead or
other suitable metal which are then made the positive and negative electrodes
respectively of an electric current in a bath of dilute sulphuric acid. As soon as
the necessary transformation has been effected the storage plates are detached from
the leaden or other metallic plates and are then ready to be mounted in a storage
cell where they should be clamped in leaden or other suitable metal or carbon
holders or frames.
These cast plates have parallel and perfectly flat sides and can therefore be
placed very close to each other in the storage cell. They are however more fragile
than the plates which contain a metallic or carbon basis and must therefore be
handled with more care until they are finally mounted in their frames. Plates of a
cylindrical or other form manufactured according to this plan can be conveniently
connected in the storage cells by casting or subsequently boring perpendicular holes
of suitable depth in them and filling these holes with mercury By means of bars
or wires of copper bent at their ends and stretching from hole to hole these plates
can be electrically connected as may be required.
The plates prepared by any of the herein before described methods take a high
charge of electro chemical energy and the hardening material becomes still harder
by use. They can be fixed in the storage cells very close to each other without
risk of short circuiting.
In all cases in which dilute sulphuric acid is directed to be used in the herein-
before described operations it must be understood that the mixture of acid and water
must be allowed to cool before it is used. And in making the hardening material
required for the second third fourth and fifth modes of operation care must be
taken that the mixture of minium or oxide of lead with dilute sulphuric acid does
not become hot otherwise the material does not afterwards harden satisfactorily.
To prevent the heating of the mixture it is advisable not to make more than about
14 lbs of it in each operation and to add at once all the required dilute acid and
to make the mixture as rapidly as possible The mixture should then be allowed
to stand for four or five minutes before use during which time it swells up
considerably.
I further wish it to be understood that I do not confine myself to the weights
volumes or proportions of the materials used in carrying out my Invention for these
weights volumes or proportions may be considerably varied but I have given those
which I have found to answer best.
Having now described and particularly ascertained the nature of my said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that I do not claim as new or original the
use of a carbon nucleus or of leaden or other metallic bases or nuclei or the use of
oxides of lead in the manufacture of plates for storage batteries but what I consider
to be novel and original and therefore claim as the Invention secured to me by
the herein before in part recited Letters Patent is:-
First. The formation of a hard coating or enamel on the surface of leaden or
other plates or in the perforations corrugations or the like of such plates or gauzes
to be used in storage batteries in the mode or modes substantially as hereinbefore
described which hard coating or enamel is afterwards rendered active by the current
from a dynamo electric machine or other source of electricity.
Secondly. For plates for electric storage batteries the use of a hardening mixture
consisting of any oxide of lead except the peroxide with sulphuric acid more or
less dilute or a solution of phosphoric acid or hydrochloric acid or a solution of
oxalic acid or any other acid or solution thereof which forms an insoluble or nearly
insoluble salt of lead which mixture sets or hardens after a short time the said
mixture being applied as a coating upon any metallic or other plates to be used in
secondary or storage batteries in the mode or modes substantially as herein before
described.

page_text: Thirdly The use of the same mixture for casting upon in or around any plates
(perforated corrugated or otherwise formed) to be used in storage batteries
substantially as hereinbefore described.
Fourthly. The use of the same mixture for dipping the metal or other plates to
be used in storage batteries so as to cause the adhesion of one or more layers of the
bardening mixture to the plates substantially as herein before described.
Fifthly The use of the same hardening mixture for casting into plates cylinders
or blocks without any metallic or other basis or nucleus and either with or without
an admixture of powdered plumbago or coke or the filings or borings of lead or any
other suitable metal when the said plates cylinders or blocks are to be used in
storage batteries substantially as herein before described.
Sixthly The piercing of the coating or active material of storage batteries with
holes from one side to the other substantially as hereinbefore described.
In witness whereof I the said Edward Frankland have to this my Specification
set my hand and seal this first day of March One thousand eight hundred
and eighty three.
EDWARD FRANKLAND (L.S.)