IMPROVEMENTS IN ELECTRODES FOR BECONDARY BATTERIES
Year: 1884

page_text: I, RENÉ TAMINE, Engineer of Mons in the Kingdom of Belgium do hereby
declare the nature of my said invention for "IMPROVEMENTS IN ELECTRODES FOR
BECONDARY BATTERIES" to be as follows:-
The researches of electricians into the action of primary batteries of peroxide of.
lead and of peroxide of manganese have proved to them that the internal resistance
of an element is diminished when the portion forming the conductor is care-
fully surrounded by peroxide of lead, or peroxide of manganese, rather than by
liquid.
It has further been demonstrated, that the conducting power of such an
electrode increases with the approximation of the active elements, that is to say,
with the increased contiguity of the solid parts, and the diminution in the electrode
of the spaces filled with liquid. Bearing these principles in view, Leclanché
increased the approximation to the utmost by compressing the elements: he has
thus produced one of the most effective primary batteries hitherto constructed.
These considerations, of capital importance, have not apparently hitherto occurred
to the inventors of accumulators, who have proceeded on an opposite principle, that
of increasing the porosity of their electrodes, that is of increasing the open spaces
alluded to above.
The system of electrodes which forms the object of this application for Letters
Patent is devised according to the principles which guided Leclanché in the
construction of his primary batteries.
In accumulators constructed of lead on the surface of which substances such as
litharge, minium, spongy lead are deposited (accumulators belonging to the systems
of Faure, Sellon or Volkmar), it is found that these various deposits during their
conversion under the action of the electric current into brown peroxide do not
retain their original volume, but swell up and expand, consequently the adhesion
of this brown oxide to the support. being imperfect the resistance of the
accumulator increases until the electrodes cease to work altogether. Experience
shows that the positive plates become useless after one year's continuous service.
Moreover M. Faure states that the conversion into peroxide of the deposit upon
the negative plate (that which forms the positive pole) only takes place with a
small percentage of the total quantity of deposit, 10 per cent or thereabouts:
M. Faure attributes this to the resistance which the half solid matter offers to the
passage of the electrolytic wave: practically, the bulk of the substance, some
90 per cent, escapes the action of the current.
In short the accumulators with artificial deposit have two important defects
prejudicial to their industrial use: 1, The alteration in the volume of the deposit

page_text: by the transformation into brown poroxide involves the rapid deterioration of the
positive plates 2. A very large proportion of the layer of deposit oscapes the
action of the current.
In order to obviate these drawbacks, and finding by experience that the principlos
which have guided the inventors in the construction of primary batteries with
peroxide of lead and peroxide of manganese are applicable equally to secondary
batteries, the inventor has devised electrodes constructed as follows; a given
quantity of rosin heated to its fusing point, cements, under a pressure of upwards
of 100 atmospheres a mixture of brown peroxide of load (preferably obtained
electro chemically) and, of lead filings.
It is obvious that if the pressing of the mixture be effected by hand, a force of
only a few kilos per square centimetro can be exerted, and it is easy, to see that
cohesion and adherence can under theso circumstances be only imperfect. On the
other hand by means of the agglomerating process described, carried out by ineana
of a hydraulic press or other suitable mechanism, the particles of the peroxide are
in a manner soldered to a conducting material, that is, the lead filings and the
unoccupied spaces between the electrodes are reduced to a minimuin.
Independently of the coliesion thus obtained between the constituents of the
mass, it is evident that the resistance alluded to above as investigated by M. Fauro
can no longer occur here. In fact the mass of peroxide does not form a uniform
and homogeneous layer, but the particles of brown oxide, in a state of extremely
fine division nre intimately mixed with a conducting material, so that, by means of
the great pressure, the conductivity is considerably augmented, and all the brown
peroxide forming part of the electrode reacts usefully.
COMPLETE SPECIFICATION.
I, RENÉ TAMINE, Engineer of Mons in the Kingdom of Belgium do hereby
declare the nature of my said invention for IMPROVEMENTS IN ELECTRODES FOR
SECONDARY BATTERIES and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement::—
The researches of electricians into the action of primary batteries of peroxide of
lead and of peroxide of manganese have proved to them that the internal resistance
of an elemont is diminished when the portion forming the conductor is care-
fully surrounded by peroxide of lead or peroxide of manganese rather than by
liquid.

page_text: It has further been demonstrated, that the conducting power of such an electrode
increases with the approximation of the active elements, that is to say, with the
increased contiguity of the solid parts, and the diminution in the electrode of the
spaces filled with liquid. Bearing these principles in view, Leclanché increased
the approximation to the utmost by compressing the elements; he has thus pro-
duced one of the most effective primary batteries hitherto constructed.
These considerations, of capital importance, have not apparently hitherto occured
to the inventors of accumulators, who have proceeded on an opposite principle, that
of increasing the porosity of their electrodes, that is of increasing the open spaces
alluded to above.
The system of electrodes which forms the object of this application for Letters
Patent is devised according to the principles which guided Leclanché in the con-
struction of his primary batteries.
In accumulators constructed of lead on the surface of which substances such as
litharge, minium, spongy lead, are deposited (accumulators belonging to the systems
of Faure Sellon or Volkmar) it is found that these various deposits during their
conversion under the action of the electric current into brown peroxide do not
retain their original volume, but swell up and expand, consequently the adhesion
of this brown oxide to the support being imperfect the resistance of the accumu-
lator increases until the etectrodes cease to work altogether. Experience shows
that the positive plates become useless after one year's continuous service.
Moreover Mr Faure states that the conversion into peroxide of the deposit upon
the negative plate (that which forms the positive pole) only takes place with a
small per centage of the total quantity of deposit, ten per cent or thereabouts;
Mr Faure attributes this to the resistance which the half solid matter offers to the
passage of the electrolytic wave; practically, the bulk of the substance some ninety
per cent, escapes the action of the current.
In short, the accumulators with artificial deposit have two important defects,
prejudicial to their industrial use; 1. The alteration in the volume of the deposit
by the transformation into brown peroxide involves the rapid deterioration of the
positive plates. 2. A very large proportion of the layer of deposit escapes the
action of the current.
In order to obviate these drawbacks and finding by experience that the principles
which have guided the inventors in the construction of primary batteries with
peroxide of lead and peroxide of manganese are applicable equally to secondary
batteries, the inventor has devised electrodes constructed as follows: a given
quantity of rosin heated to its fusing point, cements, under a pressure of upwards
of one hundred atmospheres, a mixture of brown peroxide of lead (preferably
obtained electrochemically) and of lead filings.
It is obvious that if the pressing of the mixture be effected by hand, a force of
only a few kilos per square centimetre, can be exerted and it is easy to see that
cohesion and adherence can under these circumstances be only imperfect. On the
other hand by means of the agglomerating process described carried out by means
of a hydraulic press or other suitable mechanism the particles of the peroxide are
in a manner soldered to a conducting material, that is, the lead filings and the .
unoccupied spaces between the electrodes are reduced to a minimum.
Independently of the cohesion thus obtained between the constituents of the
mass it is evident that the resistance alluded to above, as investigated by
Mr Faure can no longer occur here. In fact the mass of peroxide does not form
a uniform and homogeneous layer, but the particles of brown oxide, in a state of
extremely fine division are intimately mixed with a conducting material, so that,
by means of the great pressure the conductivity is considerably augmented and all
the brown peroxide forming part of the electrode re-acts usefully.
To fix the pole of these electrodes a strip of lead a as wide as the thickness of
the electrode is passed through it zig zag fashion as shown in Figure 1. and is
prolonged at a¹, or the electrode is preferably constructed as follows: taking a sheet
of lead of about a millimetre in thickness (see Figure 2 of the drawings) the corners

page_text: -
aro cut out and the edges a. b. c. d, a a¹ all a¹¹¹, ¿ ¿¹. ¿¹¹ ¿¹ll are 'turned up by
placing it in a suitable mould, heating from 60 to 100 degrees centigrade and
pressing it until it takes the shape of a shallow dish; into this the above described
mixture is then placed, another similarly shaped pioce of lead is placed on top,
and the edges of the two covers soldered together. During the soldering the resin
liquefies, and the pross is turned to compress the whole mass strongly together:
one or both of the lead plates has a strip of lead attached forming the pole; or the
electrodo may be welded together as follows; the mixture as above described has a
little water acidulated with dilute sulphuric acid added to it. The whole is then
immersed in water heated to about boiling point, whereby the resin is liquefied and 1
forms an agglomerant; the whole is then taken out and pressed causing the whole
to cohere without soldering or melting the lead plates.
It is advisable to varnish over the projecting strip to enable it to resist the action
of the acidulated water. If required, the brown peroxide may be replaced by red
lead, (minium) but it has the drawback of increased bulk. The lead filings may 1
likewise be replaced by shot or by coke purified by acids, but agglomerations of
carbon have not given in practice as good results as those with lead filings.
The electrodes constructed in the manner indicated above may be employed (1) as
positive and negative electrodes of an accumulator, the bath of which is a solution
acidulated with aulphuric acid (2) as the negative electrode (giving the positive 2
pole) of an accumulator having for its positive electrode a plate of hard-carbon, the
bath being a solution of sulphate of copper, or of zinc, alightly acidulated with
sulphuric acid. (3) as positive or negative electrode of an accumulator, the other
electrode of which, consists of a piece or pieces of lead of any desired form, the bath
being of dilute sulphuric acid.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim is
2
In electrical accumulators, or secondary batteries, the use of electrodes constructed
substantially as above described and preferably composed, internally of the following 3
ingredients, in the following proportions. Resin. 6 per cent. Oxide or peroxide
of lead 45 per cent. Lead filings 50 per cent..