Improvements in the Production of a Filling Paste or Active Material for the Plates of Secondary Batteries.
Year: 1899

page_text: Date of Application, 28th Apr., 1899-Accepted, 19th Aug., 1899
Improvements in the Production of a Filling Paste or Active Material
for the Plates of Secondary Batteries.
We, CARL FRIEDRICH PHILIPP STENDEBACH, Electrical Engineer, of 45,
Plagwitzerstrasse, Leipzig, and HEINRICH MAXIMILIAN FRIEDRICH REITZ, Landed
Proprietor, of Dobitz, near Taucha, Leipzig, both in the Empire of Germany,
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 follow-
ing statement:-
-
This invention relates to the production of a filling paste or active material for
secondary batteries which differs from those hitherto known in the following
respects: In the processes hitherto known, materials are employed which, so far
as combination of lead are concerned, all contain more or less oxygen. The
process herein described embodies in addition to the combination of lead, con-
taining oxygen, a special combination of lead made for this particular purpose,
and which is either free from or contains but little oxygen but, on the other
hand, is hydrogenous, or rich in hydrogen.
66
The hydrogen in this combination of lead when combined with materials con-
taining oxygen takes the place of the oxygen therein, that is to say, mixes there-
with. As proof of the possibility of such an occurrence, reference is made to
the following works: Buchner Anorganische Chemic page 10 and page 11 etc.
as also Remsen Anorganische Chemie page 112 etc. Originating or Nascent
condition"; likewise Kolbe Kurzes Lehrbuch der anorganischen Chemie
page 45-54.
Hereby the internal resistance arising in the accumulators
where filling material, produced by any of the hitherto known methods,
was employed, is got rid of in the electrodes; instead of this resistance
there is in fact a certain electrochemical tension in the crude, that is to say,
the still un-formed electrodes. These electrodes thus possess the property of
readily producing and storing a proportionately large quantity of oxygen and
hydrogen through the medium of the electric current, because, as regards the
whole of the molecules of the collected filling material, the proportion of ingredients
necessary for the complete electrochemical conversion already exists; so that,
owing to the different stages of oxidation of the substances employed, the pene-
trating of the oxygen by the hydrogen or vice versa is considerably facilitated
according to the quantity of the hydrogen or oxygen produced by means of the
electric current. This is owing to the active particles in the filling material
being previously made very sensitive to the two substances hydrogen and oxygen;
thus it now only requires the action of the electric current in order to com-
pletely saturate the filling material on the one hand with oxygen and on the other
with hydrogen and to eliminate without resistance the substances acting in
opposition. If not absolutely necessary, it is desirable in order to allow of
the taking up of each quantity of oxygen or hydrogen and the elimination of the
hydrogen or oxygen acting in opposition, without impairing the stability of the
compressed material produced, to employ a number of forms of oxidation of

page_text: the material in succession, from peroxide down to the finest lead powder which
easily oxidises in the air.
The production of the combination of lead having but little oxygen but being
rich in hydrogen is effected as follows:-
Metallic lead is boiled gently in diluted nitric or nitrous acid and only as long
as there is no formation of crystal salts, or that a combination of the nitric acid
with the lead has not been completely effected, but the nitric acid only partly
combined with the water and the lead, and capable of being easily set free. If
the lead were to be boiled for a certain time in weak nitric acid, the nitric acid
would form a chemical combination with the lead in such a manner that the
separation of the nitric acid from the lead would no longer be possible, thus
nitrate of lead would result, whilst in the process described there is only a
technical combination of nitric acid and lead so that the former by suitable
treatment with sulphuric acid can easily be separated from the lead and whereby
the required lead preparation free from nitric acid would be obtained. After
removal of the metallic lead, zinc, coke, carbon, or the like, in the form of
strips or sticks or in other form are, introduced separately or in combination into
the cooling or cooled liquid. These strips or sticks become in a short time covered
with an exceedingly fine deposit of lead molecules which can be removed from the
strips and collected, and which is an important point, the residue of the nitric
acid is eliminated therefrom by means of diluted sulphuric acid and the com-
bination of lead kept excluded from the air, until the mixing with the rest of
the materials takes place. In mixing with oxides of lead various stages of lead
oxidation are formed, and after each formation metallic parts are also present in
the mass and heighten the effect.
These added materials consist, so far as the forming of positive electrodes is
concerned, either of binoxide of manganese in the form of powder peroxide
of lead
and
or
and
or
minium as well as litharge. Likewise, oxide of manganese, powdered
lead, binoxide of manganese
and
or
chromic acid, as also acetates of lead, graphite,
coke or carbon in the form of powder may also be added.
In the case of negative electrodes, litharge is added, or the substances as
used for the positive plates can easily be formed into negative and the negative
into positive ones. Finally, as binding material glycerin, sulphuric acid,
chloride of magnesia, sulphate of magnesia etc. may be employed.
The filling material thus produced has the following advantages:
Firstly, even when the accumulator is most strongly charged and discharged,
any damaging of the electrodes is obviated as any mechanical strain is avoided.
Secondly, the internal resistance is so reduced that it may be considered as
got rid of
Thirdly the tension of the battery remains nearly constant, until shortly before
the complete discharging.
Fourthly, the storage capacity of the electrodes, in consequence of these cir-
cumstances, is increased, likewise, the usual effect is considerably greater.
Fifthly, the tension resumes its normal condition in case the circuit is broken
or charged without impairing the elements.
Sixthly, the carriers for the filling mass, which also serve as conducting
electrodes, are scarcely affected at all, whereby the durability of these elements
is ensured for a longer time.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is:-
The improved production of a filling paste or active material for secondary
batteries, the distinguishing feature of which is that combinations of lead

page_text: (minium, litharge, etc.) are mixed with combinations of lead containing little
oxygen but being rich in hydrogen, and consisting of a preparation of lead,
produced by boiling metallic lead in diluted nitric acid, the removal of the
metallic lead, and the introduction of zinc, coke, or carbon strips or sticks
into the liquid on which strips or sticks the lead is deposited,
the residue of the nitric acid being eliminated therefrom by
means
of diluted sulphuric acid and the said preparation of lead kept excluded
from the air, until mixed, in order to avoid any premature oxidation; further
that in the mixing with oxides of lead various stages of lead oxidation are formed
and metallic parts are also present after the formation, which increase the effect,
for the purpose of obviating the internal resistance so that an exchange of oxygen
and hydrogen occurs without any disadvantageous strain of the electrodes.
Dated this 28th day of April 1899.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.