Year: 1896

page_text: Date of Application, 15th Jan., 1896
Complete Specification Left, 3rd Feb., 1896-Accepted, 21st Mar., 1896
We, DESMOND GERALD FITZGERALD. of 94, Loughborough Road, London,
S.W. Electrician, and WALTER CHARLES BERSEY, of 39, Victoria Street, in the
City of Westminster, Engineer, do hereby declare the nature of this invention to
be as follows:-
Our invention relates to voltaic batteries and more particularly to batteries used
for traction purposes in which detrimental effects are liable to be produced if means
are not provided for preventing the spilling, splashing, and spraying of the
electrolyte.
It is desirable also to pack or support these elements with solid material so as to
be able to obtain a high rate of discharge without warping or buckling the plates
and without any shedding of the active material.
Another desideratum is to obviate the production of persulphuric acid in the
operation of charging a lead accumulator. This substance, reacting upon the
dilute sulphuric acid constituting the electrolyte, generates hydrogen dioxide
which is detrimental both by reducing lead dioxide and by oxidizing and
"sulphating" spongy lead.
The substances used to absorb the clectrolyte in so-called "dry" (or absorbent)
batteries, have hitherto been found objectionable either in consequence of the
resistance they introduce in the circuit which has rendered it impossible to obtain
the high rate of discharge required for electric traction; of their being chemically
acted on by the electrolyte of their high specific gravity and the insufficient
mobility of their particles; of the difficulty of obtaining and retaining a certain
granular condition; or of their insufficient porosity.
Now the object of our invention is to construct an absorbent battery of low
resistance in which the above objections are avoided.
In carrying our invention into effect we prefer to use three substances as follows,
or it may be two of them only, in conjunction, viz. :—
1. What we may call a mechanical absorbent consisting of a siliceous material
reduced to fragments or granules varying in size according to the nature of the
battery, from that of millet to that of hemp seed. This substance should be
absorbed throughout its mass, not merely in virtue of capillarity between its
particles, and it should be practically unaffected by dilute sulphuric acid. The
material we preferably employ is that known as "Tripoli " stone," but we do not,
however, limit ourselves in this respect but may employ granules or fragments of
pumice stone or porous earthenware, e.g. the substances of which clay pipes or
porous pots are made.
2. What we term a chemical absorbent, e.g. the so-called aluminic bi-hydrate-
which not only blends mechanically with a large quantity of water but remains
chemically combined with over 26% of this compound even after exposure to a red
heat. But the chemical absorbents we prefer to use are ferro-cyanide (or ferrid-
cyanide) salts, such as the ferro-cyanide of zinc, or that of iron, both of which are
insoluble in dilute sulphuric acid, and retain chemically, as well as mechanically, a
large, proportion of water. Another salt we find well adapted for the purpose in
view is a double ferro-cyanide of zinc and potassium.
3. In admixture with both (or it may be with one only) of the above, free

page_text: sulphuric acid of about the strength corresponding to the density 1:300 at which
persulphuric acid is no longer generated. In the case of ordinary "fluid"
accumulators, users are rightly warned not to use sulphuric acid of such high
specific gravity, but we have found that in accumulators mounted according to our
present invention such acid may be used without detriment, by reason of the
retarded circulation of the electrolyte.
Our invention is applicable not only to accumulators specially constructed to
secure lightness and a very high rate of discharge but also with more or less
advantage to many of the accumulators and batteries in present use when it is
required to render these portable or, in the case of accumulators, merely to
obviate "buckling" and the shedding of active material.
Dated this 15th day of January 1896..
A. M. & W M. CLARK,
53, Chancery Lane, London, Chartered Patent Agents.
Improvements in Voltaic Batteries.
We, DESMOND GERALD FITZGERALD of 94, Loughborough Road, London,
S.W. Electrician, and WALTER CHARLES BERSEY of 39, Victoria Street, in the
City of Westminster, Engineer, do hereby declare the nature of this invention
and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement :-
Our invention relates to voltaic batteries and more particularly to batteries used
for traction purposes in which detrimental effects are liable to be produced if means
are not provided for preventing spilling, splashing, and the blowing off of the
electrolyte in the form of spray by the bubbles of gas escaping from it.
It is desirable also to pack or support these elements with solid material so as to
thereby prevent warping or buckling of the plates and shedding of the active
material by a high rate of discharge.
Another desideratum is to obviate the production of persulphuric acid in the
operation of charging a lead accumulator. This substance reacting upon the dilute
sulphuric acid ordinarily constituting the electrolyte, generates hydrogen dioxide
which is detrimental both by reducing lead dioxide and by oxidizing and
"sulphating" spongy lead.
The substances which have been used experimentally or otherwise as absorbents
for the electrolyte in so-called "dry" (or absorbent) batteries have hitherto been
found objectionable in consequence either of the high internal resistance (which
has rendered it impossible to obtain the high rate of discharge required for electric
traction) or of their being chenically acted on by the electrolyte, or of their high
specific gravity and the insufficient mobility of their particles or of the difficulty
of obtaining and retaining a certain granular condition, or of their insufficient
porosity.
Now the object of our invention is to construct what may be termed a "dry"
"afluidic" or "solid" cell of low resistance permitting of a high rate of discharge
and which is free from all the other objections above mentioned.
In carrying our invention into effect we prefer to use for the purpose of
absorbing the electrolyte a mixture of two kinds of absorbents in conjunction with
the electrolyte :-
1st. A mechanical absorbent consisting of a siliceous material which by virtue of
its porosity is absorbent throughout its mass as well as absorbent in virtue of
capillarity between its particles and which is unaffected by the sulphuric acid
used.
2nd. An electrolytically conductive absorbent. The material we preferably

page_text: employ as the mechanical absorbent is that known as "Tripoli "stone which should
be reduced to fragments or granules varying in size according to the form and.
size of the battery, from that of millet to that of hemp seed the size of the granules.
increasing with the depth of the mass through which any gases generated must.
force their way in order to escape. We do not however limit ourselves to this
particular material but may employ granules or fragments of pumice stone or
porous earthenware similar to tobacco pipes or the porous pots used in voltaic
batteries.
Such mechanical absorbent materials may be used separately or in admixture
with each other in any proportions, but in consequence of the non-conductivity of
such materials the internal resistance of the battery would be comparatively high
were such a mechanical absorbent alone to be used, and we therefore prefer to employ
a mixture of a mechanical absorbent such as above described and of an absorbent
which is also by reason of its chemical constitution an electrolytic conductor so as.
thereby to reduce the internal resistance of the battery. Such an absorbent is the
so-called aluminic bihydrate which is obtained by subjecting gelatinous aluminic
hydrate to a high temperature in order to render it insoluble in the sulphuric acid
used. This bihydrate not only blends mechanically with a large quantity of
sulphuric acid but retains over 26% of water of hydration which reuders the
absorbent electrolytically conductive. But as electrolytically conductive absorbents
we prefer to use ferrocyanide (or ferridcyanide) salts such as the ferrocyanide of
zine or that of iron which are insoluble in the sulphuric acid used, are mechanically
absorbent of the acid by forming a paste or jelly therewith, and retain by their
chemical constitution a large proportion of water which renders them inherently
electrolytically conductive in addition to the conductivity conferred by the acid.
electrolyte.
The preferred ferrocyanide salt is a double ferrocyanide of zinc and potassium-
which we obtain by mixing ferrocyanide of potassium (yellow prussiate of potash).
dehydrated by heat and reduced to powder, with sulphate of zinc (Zn SO4, 7 H₂O),
also in powder.
The absorbent mixture containing the ingredients for the production of the
double ferrocyanide of zinc and potassium (K,Zn, (Fe Cy),) is compounded as.
follows:-
Sulphate of zinc (commercial)
Yellow prussiate of potash
Granulated pumice or Tripoli stone
-
30 parts by weight.
-
- 20
"
"
"
- 100 "
"
2
وو

page_text: the absence of persulphuric acid in charging and also as regards diminution of
resistance by reason of the strength of the acid decreasing (and in so decreasing
passing through the degree of strength which is likewise the point of highest
conductivity) in discharging the cell. Moreover by reason of the fact that the
electrolyte has no free circulation the local action on the plates of acid of such
high specific gravity is merely temporary and infinitesimal in effect since although
the bulk of the acid may be of a strength which would act detrimentally on the
plates were it free to circulate, the acid at the surface of contact with the element
becomes, by reason of such local action sufficiently reduced in specific gravity to
prevent any further detrimental action.
Our invention is applicable not only to accumulators specially constructed with
a view to lightness and a very high rate of discharge but may be advantageously
applied to many accumulators (at present in use for other purposes) in order to
obviate "buckling" and the shedding of active material.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. In a secondary voltaic cell the combination, with sulphuric acid, of a siliceous
material in fragments such as "Tripoli " stone, pumice stone, or porous earthen-
ware separately or together as a mechanical absorbent for the electrolyte and as
a packing for preventing the buckling of the plates and shedding of active material
as described.
2. In a secondary voltaic cell the combination, with sulphuric acid, of a
substance, such as one or other of those mentioned, insoluble in the sulphuric acid
used, mechanically absorbent of the acid and possessing inherently the property of
electrolytic conductivity as specified.
3. In a secondary voltaic cell the combination, with sulphuric acid, of a mixture
of siliceous material such as described and of a substance, such as one of those
mentioned, insoluble in and mechanically absorbent of the acid and possessing
inherently the property of electrolytic conductivity as specified.
. Dated this 3rd day of February 1896.
A. M. & WM. CLARK,
53, Chancery Lane, London, Chartered Patent Agents.