Year: 1887

page_text: I, HENRY HARRIS LAKE of the firm of Haseltine, Lake & Co., Patent Agents
Southampton Buildings, in the County of Middlesex, 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 :-
My invention has relation to that class of batteries which are used for storing up
energy for future re-development and use, and the first part of the invention has for its
particular object the production of a battery which shall have a higher electro-motive
force than any hitherto known.
I have discovered that an accumulating battery, possessing very remarkable
properties, may be constructed by immersing plates of zinc and lead in a cell con-
taining a mercury solution, such as sulphate of mercury; a zinc solution, such as
sulphate of zinc, and free sulphuric acid; the lead plate being preferably, but not
necessarily, amalgamated. If a current be passed through this cell from the lead
(negative) to the zinc (positive) plate a porous and highly absorptive layer of mercury
and zinc will be formed on the posive plate, while at the same time the negative plate
is oxidized; the cell so prepared yielding in discharge a current of three volts electro-
motive force, and maintaining its charge without material diminution for very
considerable lengths of time. The action of this battery is conceived to be in its
principal outline as follows:
During charge, zinc and mercury are deposited on the positive plate, hydrogen at
the same time being occluded in that deposit, and proxide of lead formed on the

page_text: negative plate. If mercury is present on the negative plate, which is, as I have above
stated, thought to be desirable, it will serve to replenish the solution, preventing the
bath from being partially or wholly depleted of mercury, and promoting regular
action. In discharge the occluded hydrogen no doubt, to some extent, unites with
the excess of oxygen on the negative plate, as in the Planté battery; but the current
of discharge believe to be principally due to the following more complex reaction:
The deposit of zinc and mercury breaks up and is redissolved, the zinc, by reason of
its superior affinity, displacing the mercury in part of the molecules of mercury
sulphate. This displaced mercury in turn displaces hydrogen in the free sulphuric
acid, which in turn draws off the oxygen of the pre-oxidized negative plate. A part
of the mercury set free is also, no doubt, thrown upon the negative plate in the form
of an oxide.
The electro-motive force of the cell should therefore be equal, speaking broadly, to
that developed by the zine replacing the mercury in the mercury sulphate, supple-
mented by that developed by the liberated mercury in replacing hydrogen in the
diluted sulphuric acid, and by the displaced hydrogen in uniting with the oxygen of
the peroxide. The well known Marie Davie primary battery has an electro-motive
force of one and a-half volts developed by the displacement of mercury in mercury
sulphate by zinc; but in this battery the liberated mercury is inactive, being merely
deposited on a carbon pole-piece, while in my cell this mercury engages in further
reactions, to which the increased electro-motive force is no doubt largely due. I have
observed that this electro-motive force is not exhibited until the plates are fully
formed and charged; that is, until a substantial deposit of spongy or porous metallic
zinc and mercury is formed on the positive plate, and of peroxide on the negative
plate. The constancy of the secondary current depends upon the substantial character
of these deposits, particularly that of the zinc-mercury sponge; and the capacity of
the battery to retain its charge, which it possesses in a very remarkable degree when
properly formed, depends upon the presence of a considerable quantity of mercury on
the positive plate. In this respect the function of the mercury seems to prevent the
free sulphuric acid of the bath from acting on the zine of the positive plate.
In the ordinary zinc-lead accumulator the free acid of the solution combines with
the zinc and large volumes of hydrogen are given off. This action takes place with
the circuit open or closed, and the deposit of zine being thus rapidly redissolved the
cell soon becomes inactive. In my cell such action is prevented by the mercury
present on the positive plate protecting the zinc from attack except in discharge, and
by the capacity of the zinc-mercury sponge to occlude hydrogen. When my cell is
in perfect condition no hydrogen is given off either in charge or discharge, from
which the inference is clear that its liberation is prevented or that it is fixed or
occluded in large quantities or both in part, of which the last seems to be the most
reasonable hypothesis.
Having thus given a general view of my improved battery in what I now believe to
be its best form, and having indicated in general my theory of its action, I shall now
advert to certain subsidiary peculiarities of its action, and suggest certain modifications
which may enable the gist of my invention to be seen in a clearer light.
As to the metal used for the negative plate, it is only requisite that it be capable of
taking up oxygen to excess. By reason of cheapness and its other suitable qualities,
I have found lead to be the most valuable material, but it is evident that any con-
ducting metal, capable of taking up and giving off oxygen readily, would be in this
battery the equivalent of lead. As above suggested, the function of the positive plate,
where zinc is used in the solution, is only to furnish a conducting support for the
zinc-mercury deposit. Any metal, therefore, capable of performing this function
would be an equivalent of the zinc plate in my cell. I have found that in use a
positive plate made up of thin exterior sheets of zinc packed or filled with lead, is the
most satisfactory.
As I have indicated above, the important part is played in my battery by the
spongy porous zinc-mercury deposit, and while I desire to claim and protect herein

page_text: the described process of producing that deposit, I wish it understood that I also claim
its use in an accumulating battery, however it may be obtained; and also I claim the
described process independently of the particular form or chemical compositer of the
resulting battery plate. This deposit is altogether different in character from
the amalgamated zinc plate. The latter has a smooth and polished surface, not at
all adapted to the occlusion of hydrogen, while the electrolytically-formed surface
described is more or less rough, crystalline and spongy in appearance.
There are doubtless a considerable variety of ways in which it may be obtained
besides that which has been herein described; thus, sulphides of oxides of mercury
and zinc, with or without the addition of finely divided pure metal, might be pressed
into proper form or applied to a proper supporting and conducting structure and
reduced to the condition of spongy metal by electrolytic action in a suitable bath, the
current in such case being aided by local chemical action. I have, in fact, found by
experiment that this is a fairly effective way to form the battery, though inferior to
that first described; and I sometimes also apply mercury and lead oxides or sulphides
to the negative plate, which will more readily supply high oxidation than pure metal.
So, too, it would perhaps be practicable to make a mechanical mixture of zinc and
mercury for the positive plates, grinding up these metals, mixing them in suitable
proportions and pressing them into proper shape and forming them up clectrolytically
in the manner suggested for the treatment of sulphides and oxides.
So, too, the materials may be placed in porous cups or saucers, the deposit being in
this case formed on the top surface of the liquid.
I have selected zinc as a constituent element of my battery, for the reason that it
gives a highly electro-positive action, and also because the zinc-mercury combination
is passive in the solution when no current is flowing, but any other highly electro-
positive metal which would maintain its metallic condition in the presence of an acid
bath when associated with mercury, would probably be an equivalent of zinc in this
cell. The relative proportions of mercury and zinc, it need hardly be said, may be
widely varied without changing the essential action of the battery, and the same may
be said of the relative proportions of the salts and acids composing the electrolyte.
I believe that in actual use sulphides and sulphates of zinc, mercury and lead are
formed on the two battery plates, as well as the various oxides of those metals, and it
is probable that their presence has an effect relative to the high electro-motive force
exhibited. I wish it understood, therefore, that I regard the metals in these forms as
equivalents in my battery of pure spongy inetal. While, as above stated, any material
may be used for the positive plate which will act as a conducting support for the
mercury-zinc deposit, still I believe a zinc plate to be preferable, for the reason that a
deposit of zinc is more readily made upon a zinc plate than upon a plate of another
metal, and enters into closer and more compact union with the plate than it would
with a plate of other material. For this reason, as stated, I consider a thin plate of
zinc, furnished with the requisite strength by backing of lead or other conducting
material, to be the best form of plate.
A further explanation of the remarkable electro-motive force of this battery may be
found in the superior capacity of the electrolytic zinc-mercury sponge to occlude
hydrogen and the peculiar qualities of the hydrogen so occluded, due to the conditions
under which it is taken up. And again, the efficiency of the positive plate being for
this reason exceptionally great it is probable that superior efficiency is induced thereby
in the negative plate, causing an exceptionally favorable oxidation of the latter plate.
am inclined to believe that in the process of charging oxygen in the form of ozone
is taken up on the negative plate, and that the electro-motive force exhibited may be
in part due to this fact.
I
With regard to the action of my battery I should further say that 1 believe the
mercury upon the negative plate to have a value in the battery as an active material,
especially when electrolytically deposited as in my cell; and further, that its presence
on that plate facilitates oxidation and deoxidation of the other active materials of that
plate, adding in this way to the electro-motive force of the cell; and further, that

page_text: there are probably reactions among the various salts and basic compounds of mercury
which are formed in the cell and between these salts and bases and the other materials
contained in the cell, which are too obscure to be followed theoretically. I therefore
do not rest my application upon the explanation advanced, although it is the best
which I am now able to offer, and I believe it to correspond with the facts. I proceed
upon the supposition that my patent will be construed to cover the battery I have
invented, whether or not the theory of its action advanced proves to be in whole or in
part accurate.
In my use of the term "single fluid," as applied to secondary batteries in this
specification, I intend to distinguish between a battery of the sort shown herein and
a battery having multiple electrolytic fluids, in which latter class I place all batteries
in which the two electrodes are immersed respectively in solutions differing from each
other in chemical composition and chemical equivalency, and in which the separation
of these solutions from each other is maintained by a porous partition or the like. I
intend to include all other secondary batteries under the term "single fluid" secondary
batteries.
Having now particularly described and ascertained the nature of the said invention
and in what manner the same is to be performed as communicated to me by my
foreign correspondent I declare that what I claim is
1. The improvement in preparing secondary batteries which consists in forming up
the positive and negative pole pieces or plates, by immersing them in a single Huid
bath of mercury and zinc solutions and passing an electrical current through them
and the liquid.
2. The improvement in preparing secondary batteries, which consists in forming up
zinc and lead plates, therefore by immersing such plates in a single fluid bath
containing a solution of mercury and passing an electrical current through them and
the bath.
3. The improvement in preparing secondary batteries, which consists in immersing
the plates in a single fluid bath, containing mercury and zinc in solution, together
with a free acid and forming up the same in use by passing an electrical current
through the plates and the bath.
4. A secondary battery in which both plates are immersed in an electrolyte which
contains sulphate of mercury and the positive plate or pole piece is composed wholly
or in part of zinc.
5. A secondary battery in which both plates are immersed in an electrolyte composed
of a solution of mercury mixed with a solution of zinc with or without free acid."
6. A secondary battery in which both plates are immersed in an electrolyte composed
of sulphate of mercury and sulphate of zinc, with or without free sulphuric acid.
7. In a secondary battery a positive pole piece made up of a thin zinc plate backed
by a separate plate of lead or other conducting material.
8. A secondary battery having a single electrolytic fluid in which the active
material of the positive element consists of an electrolytically formed layer of zinc
and mercury, substantially as set forth.
9. A single fluid secondary battery in which the active material of the positive
plate is electrolytically combined zinc and mercury, and the active material of the
negative plate is lead, substantially as set forth.
10. A single fluid secondary battery in which the active material of the positive
plate consists of zinc and mercury electrolytically combined, and the active material
of the negative plate consists of lead and mercury, substantially as set forth.
11. A single fluid secondary battery in which the active material of the positive
plate is mercury electrolytically combined with zinc and the electrolyte whereof
contains mercury in solution, substantially as set forth.
12. A single fluid secondary battery in which the active material of the positive
plate consists of mercury electrolytically combined with zinc and the electrolytic
fluid whereof contains mercury and zinc in solution, substantially as set forth.

page_text: 13. A single fluid secondary battery, in which the active material of the positive
plate consists of mercury electrolytically combined with zinc, the active material of
the negative plate is lead, and the electrolyte whereof contains mercury in solution,
substantially as set forth.
14. A single fluid secondary battery, wherein the active material of the positive
plate consists of a layer of mercury and zinc electrolytically formed, the active
material of the negative plate is lead, and the electrolyte whereof contains zinc and
mercury in solution, substantially as set forth.
Dated this 22nd day of March 1887
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London,
Agents for the Applicant.