Improvements in Plates or Electrodes for Secondary Batteries.
Year: 1888

page_text: Date of Application, 26th Oct., 1888
Complete Specification Left. 26th July, 1889-Accepted, 7th Sept., 1889
PROVISIONAL SPECIFICATION.
[Communicated from abroad by LOUIS DUNCAN, of the City of Baltimore, in the
County of Baltimore, and State of Maryland, United States of America,
Electrician.]
Improvements in Plates or Electrodes for Secondary Batteries.
I THOMAS JOHN HANDFORD of 50 Bedford Row in the County of Middlesex,
Patent Agent, do hereby declare the nature of this invention to be as follows:-
:-
The object of this invention is to increase the efficiency and economy of secondary
batteries by overcoming certain difficulties which have heretoforo arisen with such
batteries. There have been hitherto two kinds of plates used as electrodes for
secondary batteries. In one of these, known as the Planté form, the plates consist
of a core of lead or lead alloy on which peroxide of lead, which forms the activo
material, is electrolytically formed; and the other, the Faure plate, has a core of
lead or lead alloy which is provided with cells or recesses in which the active material
is placed mechanically.
In the Planté form, the lead plate or core has to be thick and heavy, and the
active material therefore must be thickly deposited in order to bear an effective
ratio to the weight of the inactive part of the plate. The process of producing
this thick deposit is a slow and tedious one. In a cell of such size as can be con-
veniently handled and used, only a comparatively small number of these thick heavy
plates can be placed, and the discharging surface per pound of material is small.
Another very important difficulty is the local action between the peroxide of lead
and the lead plates, and also in the peroxide itself between the different layers of the
deposit. Such local action is a cause of loss, and results also in the destruction and
falling off of the active material, which produces an uneven discharge from the
surface of the plate; and in the buckling of the plate which causes short circuiting;
and gradually the whole plate will be reduced to peroxide of lead and it will fall to
pieces.
In the Faure plate the same difficulties occur. The plate is heavy and bulky and
the local action occurs and this disintegrates the active material so that it falls out
of the cells.
My foreign correspondent overcomes these difficulties, that is he decreases the
size and weight of the plates, enables the surface to be increased in proportion to
the size of the plates, simplifies and quickens the process of formation increases the
ratio of the active to the inactive inaterial of the plate and does away with the
local action and the ill effects consequent upon it.
To this end, the invention consists mainly in providing the supporting and con-
ducting base plate or core of the electrode with a protecting covering which is
impervious to the acid solution used as an electrolyte in the battery and outside of
which the active material is placed. This protecting covering consists of a hard
dense coating of an oxide of lead which is produced in the following way:
The supporting plate or core which is usually of lead or an alloy of lead, but
may be of any suitable conducting material and any suitable shape, is made the anode
in an electrolytic bath which contains an alkaline solution of a salt of lead; a
saturated solution of litharge in caustic soda or potash is found best for this purpose.
A very weak current is applied to the bath, the cathode of which should be a
lead plate, and while the electrolysis is going on, the liquid is agitated either by
shaking the bath, or, shaking, the plates, by stirring the liquid by means of a blast of
air, by keeping up a circulation of the liquid or in any other suitable and convenient
way.
This results in the formation upon the anode of the bath, of a deposit of an oxide

page_text: of lead which coats the same completely. This coating is of a black color, is very
dense, hard, homogeneous and even, adheres with great tenacity to the plate, and i
impervious to such acid solutions as are used with secondary batteries. It may be
made as thin as desired. It increases the stiffness of the plate but is sufficiently
flexible to permit the plate to bend if necessary.
On the outside of the impervious coating the active material is applied. This may
be done mechanically or electrolytically. The process which my said foreign corre-
spondent prefers to use is to deposit rapidly from an alkaline solution of salt of lead,
using a heavy current and heating the solution. This produces on the outside of
the protecting coating another coating or layer of peroxide of lead, which is of a
loose or porous formation, but which adheres with sufficient firmness to the plate and
may be made of any desired thickness.
It will be seen that the impervious layer placed between the core and the active
material shuts off the core from all electrolytic action when in use, so that the core
is merely a support and a conductor, and is not appreciably affected or changed in
using the battery.
This being the case, my said foreign correspondent is enabled to greatly decrease the
thickness and weight of the plate, and if desired to make it of metals other than lead
and which have the advantage of greater strength or greater conductivity than lead.
Furthermore the layer of active material may be made much thinner than heretofore,
whereby the amount of local action within the active material itself will be much
decreased. My said foreign correspondent can however, further, make the active
layer thick enough to bear a much greater ratio than heretofore to the thickness of
the inactive material or core, which evidently will increase the efficiency of the
plate.
It will also be seen that with the thin plates a much greater surface and greater
charging and discharging capacity is obtained in proportion to the weight and a
much greater number of plates can be assembled in a cell of convenient size.
The durability of the plates is of course also much increased, since the core or
base plate remains unchanged, in use, and since there is little or no effect in the
active material; the charge and discharge is more even throughout the surface,
and therefore the battery can be charged and discharged more quickly.
It is evident that the invention is applicable, either to plates having a plain
surface, or to those having cells or depressions for holding the active material.
As above stated, the use of the protecting coating enables my said foreign
correspondent to use for the core or supporting plate, metals other than lead
or lead alloy, such as iron or copper for instance, which metals are superior in
strength or in conductivity to lead or its alloys. My said foreign correspondent
has found, however, that although he may use such metals for the main portion
of the core, it is often advantageous that at least the surface of the core should
be of lead, because the protecting coating applied in the manner above set forth,
adheres well to a lead surface, and because if local action should occur by any
possibility, it will be less injurious with a lead surface than with one of a different
metal. A feature of the invention is therefore the use of a plate consisting mainly
of some other metal than lead, and having a surface coating of lead, when such 4
plate is provided with an impervious protecting coating as above described. My
said foreign correspondent takes a thin plate of iron, copper, bronze or such other
material as may be selected and which may have a plain surface or be provided
with cells or depressions, and he washes this plate with lead so as to form a thin
surface coating of that metal. He then proceeds to apply the impervious coating and 5
the active material as above described. Of course the active material may be applied
mechanically after the manner of the Faure process above referred to.
Dated this 26th day of October 1888.
THOS. J. HANDFORD,
50, Bedford Row, London, W.C.-

page_text: COMPLETE SPECIFICATION.
Improvements in Plates or Electrodes for Secondary Batteries.
I, THOMAS JOHN HANDFORD, of 50 Bedford Row, in the County of Middlesex,
Patent Agent, do hereby declare the nature of this invention, a communication to me
from abroad by Louis Duncan, of the City of Baltimore, in the County of Baltimore,
and State of Maryland, United States of America, Electrician, and in what manner
the same is to be performed, to be particularly described and ascertained in and by
the following statement :-
The object of this invention is to increase the efficiency and economy of secondary
batteries by overcoming certain difficulties which have heretofore arisen with such
batteries. There have been hitherto two kinds of plates used as electrodes for
secondary batteries. In one of these, known as the Planté form, the plates consist
of a core of lead or lead alloy, on which peroxide of lead, which forms the active
material, is electrolytically formed; and the other, the Faure plate, has a core of lead
or lead alloy, which is provided with cells or recesses, in which the active material is
placed mechanically.
In the Planté form, the lead plate or core has to be thick and heavy, and the active
material therefore must be thickly deposited in order to bear an effective ratio to
the weight of the inactive part of the plate. The process of producing this
thick deposit is a slow and tedious one. In a cell of such size as can be con-
veniently handled and used, only a comparatively small number of these thick heavy
plates can be placed, and the discharging surface per pound of material is small.
Another very important difficulty is the local action between the peroxide of lead and
the lead plates, and also in the peroxide itself between the different layers of the
deposit. Such local action is a cause of loss, and results also in the destruction and
falling off of the active material, which produces an uneven discharge from the
surface of the plate; and in the buckling of the plate, which causes short circuiting;
and gradually the whole plate will be reduced to peroxide of lead and it will fall to
pieces.
In the Faure plate the same difficulties occur. The plate is heavy and bulky, and
the local action occurs, and this disintegrates the active material, so that it falls
out of the cells.
This inventor overcomes these difficulties, that is, he decreases the size and weight
of the plates, enables the surface to be increased in proportion to the size of the
plates, simplifies and quickens the process of formation, increases the ratio of the
inactive to the active material of the plate, and does away with the local action and
the ill effects consequent upon it.
To this end the invention consists mainly in providing the supporting and con-
ducting base plate or core of the electrode with a protecting covering, which is
impervious to the acid solution used at an electrolyte in the battery, and outside of
which the active material is placed. This protecting covering consists of a hard
dense coating of an oxide of lead, which is produced in the following way.
The supporting plate or core, which is usually of lead or an alloy of lead, but
may be of any suitable conducting material, and any suitable shape, is made the anode
in an electrolytic bath which contains an alkaline solution of a salt of lead; a saturated
solution of litbarge in caustic soda or potash is found best for this purpose. A very
weak current is applied to the bath, the cathode of which should be a lead plate,
and while the electrolysis is going on, the liquid is agitated, either by shaking the
bath, or shaking the plates, by stirring the iiquid by means of a blast of air, by
keeping up a circulation of the liquid, or in any other suitable and convenient way.
This results in the formation upon the anode of the bath, of a deposit of an oxide
of lead, which coats the same completely. This coating is of a black color, is very
dense, hard, homogeneous, and even, adheres with great tenacity to the plate, and is
impervious to such acid solutions as are used with secondary batteries. It may be
made as thin as desired. It increases the stiffness of the plate, but is sufficiently
flexible to permit the plate to bend if necessary.

page_text: the outside of the impervious coating the active material is applied. This m
be done mechanically or electrolytically. The process which the inventor prefers
use is to deposit rapidly from an alkaline solution of salt of lead, using a hea
current and heating the solution. This produces on the outside of the protecti
coating, another coating or layer of peroxide of lead, which is of a loose or poro
formation, but which adheres with sufficient firmness to the plate and may be made
any desired thickness.
It will be seen that the impervious layer placed between the core and the acti
material, shuts off the core from all electrolytic action when in use, so that the core
merely a support and a conductor, and is not appreciably affected or changed i
using the battery.
This being the case, the inventor is enabled to greatly decrease the thickness an
weight of the plate, and if desired to make it of metals other than lead and whic
have the advantage of greater strength or greater conductivity than lead. Further
more, the layer of active material may be made much thinner than heretofore, whereby
the amount of local action within the active material itself will be much decreased
The inventor can however, further, make the active layer thick enough to bear a much
greater ratio than heretofore to the thickness of the inactive material or core, which
evidently will increase the efficiency of the plate.
It will also be seen that with the thin plates, a much greater surface and greater
charging and discharging capacity is obtained in proportion to the weight, and a much
greater number of plates can be assembled in a cell of convenient size.
The durability of the plates is of course also much increased, since the core or base
plate remains unchanged, in use, and since there is little or no effect in the active
material; the charge and discharge is more even throughout the surface, and there-
fore the battery can be charged and discharged more quickly.
It is evident that the invention is applicable either to plates having a plain surface,
or to those having cells or depressions for holding the active material.
As above stated, the use of the protecting coating enables the inventor to use for
the core or supporting plate, metals other than lead or lead alloy, such as iron or
copper, for instance, which metals are superior in strength or in conductivity to lead
or its alloys. The inventor has found however, that although he may use such metals
for the main portion of the core, it is often advantageous that at least the surface of
the core should be of lead, because the protecting coating applied in the manner above
set forth, adheres well to a lead surface, and because if local action should occur by
any possibility, it will be less injurious with a lead surface than with one of a
different metal. A feature of the invention is therefore the use of a plate consisting
mainly of some other metal than lead and having a surface coating of lead, when
such plate is provided with an impervious protecting coating as above described. The
inventor takes a thin plate of iron, copper, bronze, or such other material as may be 4
selected and which may have a plain surface or be provided with cells or depressions,
and he washes this plate with lead so as to form a thin surface coating of that metal.
He then proceeds to apply the impervious coating and the active material as above t
described. Of course the active material may be applied mechanically after the
manner of the Faure process above referred to.
My invention is illustrated in the accompanying drawing.
Figure 1 is a view in clevation of a simple plate embodying the invention,
portions of the different layers of the material being broken away to show those
beneath them.
Figure 2, a cross section of part of the plate.
Figure 3, a cross section of part of a plate which is provided with cells or recesses
for the active material, such active material being however omitted in the drawing in
order to illustrate the plate more clearly.
Figure 4 is a view similar to figure 1, of a compound plate, and Figure 5, a cross
section of a portion of the same.
In figures 1 and 2, A is the plate of lead or lead alloy, B is the impervious pro-
ecting coating applied in the manner above set forth, and C is the external layer of
4.
50
55

page_text: active material. In figure 3 the lead plate A is formed with cells or depressions a, as
will be well understood, and all the surface of the plate is covered with the impervious
protecting material B. In figures 4 and 5, D is a thin plate of metal other than lead,
such as iron, copper, bronze, etc. E is a thin coating of lead produced by washing
in lead as above described, B is the impervious protecting coating, and C the
external layer of active material.
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. The construction and use of plates or electrodes for secondary batteries, in
which the core or supporting plate is provided with an impervious protecting covering,
and external to which protecting covering is placed the active material, substantially
as hereinbefore described.
2. The construction and use of plates or electrodes for secondary batteries, in which
the supporting plate or core is made of a metal other than lead, which has a
surface coating of lead, when such plate is provided with an impervious protecting
covering between it and the active material, substantially as herein before described.
THOMAS JOHN HANDFORD.
By Harris & Mills,
23, Southampton Buildings, London, Agents.
THOMAS JOHN HANDFORD.
By Harris & Mills,
23, Southampton Buildings, London, Agents.