Improvements in Electric Accumulators.
Year: 1898

page_text: Date of Application, 19th July, 1898-Accepted, 4th Mar., 1899
COMPLETE SPECIFICATION.
Improvements in Electric Accumulators.
I, EWALD LEIMER, of 110, Kôpnickerstrasse, Berlin, in the Empire of Germany,
Engineer, do hereby declare the nature of my said invention and in what manner
the same is to be performed to be particularly described and ascertained in and
by the following statement:-
In many branches of the industry and traffic in which accumulators are employed,
the want of an accumulator battery capable of being rapidly charged and dis-
charged has been long felt. Of the three systems at present in vogue viz. 1: solid
mass plates, 2; grated plates and 3: Planté plates, the latter only comes into
consideration, and even this system would have to be modified in many respects
before it could be employed in connection with a tram line having combined
systems. Each of the above systems has its own capacity peculiar to the said
system, thus for instance a Planté accumulator for rapid charging (hour to 1 hour)
has a capacity of 2.8 Ampere hours per 1 kilogram total cell weight, all
accumulators having grated plates, of the later types of this system and capable
of being charged within from 3 to 10 hours and discharged within the same
time, have a capacity of 7 Ampere hours per kilo. total cell weight and all the
later type solid plate accumulators, for charging and discharging in 12 to 20 hours
show an average capacity of 15 Ampere hours per kilo, cell weight. In all, cases
the durability is low and the reason for this short durability in all systems is
probably the same, nor is it probable that the durability will be increased if
inventors continue to follow the course hitherto taken. Experiments have shown
that of the total loss of active mass of the positive electrodes, 85% takes place during
the charging and 15% during the discharge.
The active mass operates as a chemically composed conductor and as such is
constantly subjected to chemically and mechanically produced changes of its
condition, then again the electrolyte is chemically altered. As a product of these
chemical alterations, the energetic formation of gas bubbles may be considered, which
invariably takes place when large currents are charged and discharged. Since the
decomposition of the active mass or of the electrolyte takes place mainly at the
contact points of both and consequently at the points of contact with the lead grid
or frame, the active mass is washed and crumbled off by the local chemical effect on
Then again
the one hand and the mechanical action of the gas bubbles on the other.
the gases generated in the mass expand and cause the same to crumble from within,
owing to imperfect porosity of the mass. Schoop has determined that the active
mass, during the charging passes through several hundred different phases of its
chemical condition, of which phases about sixty only are known. All these facts
taken together give the reason of non-durability of the active mass. The present
invention comprises an accumulator system founded on an entirely new principle.
The object of the invention is to separate the double object of the electrodes
and to transmit the destroying influences to electro chemically indifferent
electrodes.
According to the present invention solid mass plates made by a special process äre
employed as discharge electrodes, which are charged by means of correspondingly

page_text: arranged Plante plates of hard metal composition and having a large superficial
area, in such manner as to cause the charging current to effect an even positive
charge, straight through the active mass of the discharge electrodes (mass) next which
the positive charging electrodes (Plante) are arranged, whilst an even negative charging
is effected, into the negative discharging electrode (mass) next which a negative
charging electrode (Plante) is arranged. Since the charging electrodes are insulated
from the similarly named discharging electrodes, and are only in contact with the
same through the electrolyte, the gas bubbles generated will only appear on the
surface of the charging electrodes and since these are made of non-oxydisable metal,
the bubbles will rise to the surface without attacking the same.
In order to render the mass electrodes suitable for a rapid discharge the whole of
their adjacent surfaces are covered by a thin comb-like plate of non-corrosive metal,
capable of resisting the action of acids, being an alloy of lead containing
from 4 to 10% of antimony, the said plates being tightly pressed on to the mass and
thus increasing the contact surface between the frame and the active mass, to such
an extent as to render the latter capable of being discharged as quickly as the Planté
plates.
And in order to render the present Specification more easily intelligible reference
is had to the accompanying drawing in which similar letters of reference denote
similar parts throughout the several views:
Fig. 1 shows a cell broken away to show the various layers of which the same is
formed and Fig. 2 is a horizontal section through the same.
In the receptacle a, which is of material capable of withstanding the action of
acids, the prismatic supporting beams 6 61 are mounted, which carry the plates and
the insulated system, composed in the following manner :-
The negative charging electrode c lies next the wall of the receptacle and insulated
from this by means of the ebonite comb or grate d¹-d is the negative discharging
electrode e. Next this latter electrode is a grid or grate 18 (11 of metal
composition and of the same shape as the grate d¹ d' on this lies a perforated
ebonite plate f, on this again a second grid or grate of metallic composition 1521.
The upwardly extending electrode arm i belongs to the negative discharging
electrode e and k to the charging electrode c, l to the positive charging electrode h
and m to the positive discharging electrode g. The cell is closed in the well
known manner by a cover n, which may be rendered tight by means of insulating
mass.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is performed I declare that what I
claim is
1-Accumulator construction for rapid charging and discharging, with strong
currents, and attaining greater durability of the electrodes, characterised by
a: Mass electrodes serving for the discharge only, and having their entire
effective superficial area covered with thin perforated plates of metal
of a non-oxydisable nature and capable of withstanding the action of
acids.
b: By charging the discharging electrodes from separate metal plates insulated
from the same, in such manner as to cause the charging current to
pass from these metal plates only, in a straight line past the surface
of the active mass of the discharging electrodes and thus charge the
same.
2: A special form of the device covered in Claim 1, according to which the positive
charging electrodes is insulated and with small intermediate space mounted between
two positive discharging solid mass plates, the latter having those of their surfaces
which are turned away from the positive charging electrode, covered by suitable
perforated metal plates, next each of which a negative, insulated discharge electrode

page_text: is arranged, having its surfaces which are adjacent the positive discharge electrodes
covered with similar metal plates, which are again embraced by a closely situated,
insulated negative charging electrode.
3: The combination of a number of the systems covered by Claim 2 in one cell in
order to attain a higher capacity substantially as described.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.