Improvements connected with Accumulators or Secondary Batteries in Electrically Propelled Vehicles.
Year: 1897

page_text: Date of Application, 4th Jan., 1897
Complete Specification Left, 23rd-Oct., 1897-Accepted, 27th Nov., 1897
PROTIONAL DITUITUATION.
Improvements connected with Accumulators or Secondary Batteries
in Electrically Propelled Vehicles.
I, CARL RODERBOURG, of 26, Kornerstrasse, Hagen, Westphalia, in the German.
Empire, Engineer, do hereby declare the nature of this invention to be as
follows:-
Accumulators or secondary, batteries which are fitted in vehicles or cars propelled
by electromotors in order to drive such vehicles in those places in which there are
no leads for directly conducting the current to the electromotor in the vehicles and
which are charged during the journey, by the said conductors have hitherto been
simply connected up with the motor in parallel. The battery is, like the motor,
connected at one pole with the overhead conductor and at the other pole with the
rails, that is to say, with the earth conductor by means of the vehicle frame when
the vehicle is driven by the current from a dynamo.
In this manner the battery is charged at the same time as the vehicle or car
is propelled so that when a place is arrived at where there are no conductings
the motor is supplied with current from the secondary battery.
When charging the accumulators or secondary battery the said battery receives
current until its electromotive force, inclusive of the polarization occasioned towards
the end of the charging operation through the production of gas, is equal to the
voltage of the current in the conductors.
In practice it has been found that this method possesses two disadvantages.
Firstly, the efficiency of the batteries by this method of connecting up is consider-
ably reduced. If the accumulators be charged with a constant tension or difference
of potentials between their two poles it is necessary to employ in the circuit from
the first a voltage which is equal to the electromotive force of the battery towards
the end of the charging operation and which is considerably higher than would be
necessary, under other circumstances, for the larger part of the period of charging.
Secondly, the voltage in the system must above all be maintained constant
so that the battery of a car which is in the neighbourhood of the power station
does not become overcharged whilst those batteries which happen to be a con-
siderable distance from the said station do not remain insufficiently charged.
Both these difficulties are overcome by connecting the battery with the motor
in series instead of in parallel for the whole or at any rate towards the end of the
charging operation.
Batteries have already been charged in series with the motor in order, for instance,
to separately excite the magnets through the medium of a small battery for braking
by means of the motor. But in such cases the accumulators were small and the
electromotive force of the same could be left out of account in comparison with
the voltage of the current in the circuit.
Here, however, it is a question of batteries the electromotive force of which

page_text: is equal to the voltage of the leads or conductors or practically so and which are
employed to drive the car alone for certain distances.
My invention can be carried out in various ways.
The most advantageous method is to divide the battery into two equal parts
each designed for half the electromotive force of the circuit and to employ two
motors each likewise designed for half the voltage of the conductors or leads. In
this arrangement when charging the battery both halves of the same are connected
in series with their respective motors so that one battery with its motor is connected
up in parallel with the other battery with its motor.
•
The current proceding from the dynamo through the lead or conductor is divided
in the car and passes not only through the motors but also through the batteries
for the purpose of charging the same. These batteries, however, only consume
current corresponding to their difference of potential at this period when the current
strength or intensity is not very high whilst when the batteries are connected
up in parallel, as heretofore, either the battery takes so much current that the
polarization set up thereby in combination with the internal resistance raises the
difference of potential of the battery. to the same level as the tension in the con-
ducting wires or, in case the current strength. is. too high for the battery, the
current is reduced to the required limit by switching on resistances whereby in
both cases undue loss of energy is bound to: occur.
After the battery has been charged by the above described method of connection
and before a place is reached where there are no leads or conductors the two halves
of the battery are connected together in series, the two motors being also connected
together in series one of them being put in connection with the overhead lead or
conductor and the other with the earth connection. The two half batteries now
possess together exactly the average electromotive force and serve to maintain
the tension of the circuit in the neighbourhood of the car, approximately constant,
and when the car is running for instance give current to the motor which current
they again receive occasioning only a small consumption of the current supplied
to the car. The above described method of coupling or connecting the accumulator
or battery is hereinafter referred to as method No. 1.
When the car reaches a point at which there are no conductors the battery has
to furnish alone the current for propelling the same and for this purpose the con-
nection may remain unaltered. In such cases, however, at points where there
are no conductors the following method (hereinafter referred to as method No. 2)
of connecting up can be employed tamely both half batteries and both motors
can be connected up in parallel. In this case there is in the car a difference of
electrical potential equal to only half the voltage of the circuit. When the battery
is wholly discharged it can be again charged at first by coupling the batteries and
motors in the manner described in method No. 1 for discharging the batteries,
the number of cells being so chosen that this number multiplied by 2-2 is equal
to the voltage of the current flowing through the conductors. The charging opera-
tion is completed by coupling each battery in series with its motor and the two
pairs (each composed of battery and motor) in parallel as above described under
method No. 1..
If it be desired to dispense with the equalizing action of the battery on the
voltage of the conductors in method No. 1, and which takes place when the con-
ductors at the power station or at any other point of the circuit are connected up
in parallel with a larger stationary secondary battery for equalizing the tensions,
.I can employ instead of the two half batteries a single battery having half the
number of cells of double the size. By this means special advantages are obtained,
namely, the battery is on the whole cheaper and also lighter. This method is
hereinafter referred to as method No. 3. The stationary accumulator or secondary
battery is connected in parallel with the dynamo for generating the current.
In this case the motors, which are coupled together in parallel are connected
in series with the battery. When the charging of the battery is completed and
before the point is reached at which there are no conductors or leads the battery

page_text: is disconnected from the over head conductor as also from the motors and the latter
are coupled up in series. If desired, however, the battery can be connected up
in parallel with one of the two motors.
When the car arrives at a point unprovided with leads or conductors the motors
are arranged in parallel with the battery.
By the employment of two motors of half the electromotive force I do not lose
the advantage derived from the use of two motors that is to say should one motor be
injured or become useless the other motor can be utilized for propelling the car.
In some cases this is also possible after the connection with the injured motor has
been broken.
-
With the above described arrangement of accumulators or secondary batteries
in motor cars if it be arranged that the consumption of energy of the car, when
driven by the battery, is approximately the same as when driven by the dynamo
directly I can employ only one battery and one motor of half the electromotive
force. When current flows from the dynamo through the lead or conductor the
battery and motor are coupled up in series so as to charge the battery. When
the battery propels the car on the portion of its course having no conductors the
positive and negative poles of the battery are connected to the positive and negative
poles respectively of the motor.
This arrangement (hereinafter referred to as method No. 4) also has the advantage
that the battery is of low cost and of light weight in comparison with batteries
of the full electromotive force and having a double number of cells of half the size.
It can, however, only be employed when, as above described, the consumption of
energy on the part of the course having conductors is approximately equal to that
on the part of the course without conductors.
Cases may occur in which the battery is only required to propel the car over
street crossings, bridges or other approximately short distances at a slow speed.
In such cases a motor (or two motors) designed for the full voltage of the circuit
is employed and connected up according to methods 3 and 4 whilst the battery
is designed for the half or for any other fraction of the voltage. The charging
of the battery in these cases only takes place at starting or when the cars are running
slowly (otherwise it would be necessary to employ resistances) and costs practically
nothing as the energy if not so stored up would be transformed into heat by
resistance. For quicker journeys the battery is switched off and the motor is then
only connected with the conductors according to method No. 3. When the battery
is required to propel the car over street crossings, bridges, etc., the method of con-
nection described with reference to the said methods No. 3 or No. 4 is employed.
Dated the 4th day of Tonno 1807
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
Improvements connected with Accumulators or Secondary Batteries
in Electrically Propelled Vehicles.
I, CARL RODERBOURG, of 26, Kornerstrasse, Hagen, Westphalia, in the German
Empire, 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:
Accumulators or secondary batteries which are fitted in vehicles or cars propelled
by electromotors in order to drive such vehicles in those places in which there are

page_text: no leads for directly conducting the current to the electromotor in the vehicles and
which are charged during the journey by the said conductors have hitherto been
simply connected up with the motor in parallel. The battery, is, like the motor,
connected at one pole with the overhead conductor and at the other pole with the
rails, that is to say, with the earth conductor by means of the vehicle frame when
the vehicle is driven by the current from a dynamo.
In this manner the battery is charged at the same time as the vehicle or car
is propelled so that when a place is arrived at where there are no conductors
the motor is supplied with current. from the secondary battery.
When charging the accumulators or secondary battery the said battery receives
current until its electromotive force, inclusive of the polarization occasioned towards
the end of the charging operation through the production of gas, is equal to the
voltage of the current in the conductors."
In practice it has been found that this method possesses two disadvantages.
Firstly, the efficiency of the batteries by this method of connecting up is consider-
ably reduced.
If the accumulators be charged with a constant tension or difference
of potentials between their two poles it is necessary to employ in the circuit from
the first a voltage which is equal to the electromotive force of the wattery towards
the end of the charging operation and which is considerably higher than would be
necessary, under other circumstances, for the larger part of the period of charging.
Secondly, the voltage in the system must above all be maintained constant
so that the battery of a car which is in the neighbourhood of the power station
does rot become overcharged whilst those batteries which happen to be a con-
siderable distance from the said station do not remain insufficiently charged.
Both these difficulties are overcome by connecting the battery with the motor
in series instead of in parallel for the whole or at any rate towards the end of the
charging operation.
Batteries have already been charged in series with the motor in order, for instance,
to separately excite the magnets through the medium of a small battery for braking
by means of the motor. But in such cases the accumulators were small and the
electromotive force of the same could be left out of account in comparison with
the voltage of the current in the circuit.
Here, however, it is a question of batteries the electromotive force of which
is equal to the voltage of the leads or conductors or practically so and which are
employed to drive the car alone for certain distances.
My invention can be carried out in various ways and to enable it to be fully
understood I will describe it by reference to the accompanying drawings, in
which:-
:-
Figure 1 is a diagrammatic view illustrating the ordinary method of connecting
up:
Figures 2, 3 and 4 are similar views shewing methods of connecting un accord-
ing to my invention.
The most advantageous method of proceeding according to the invention is to
divide the battery into two equal parts each designed for half the electromotive
force of the circuit and to employ two motors each likewise designed for half the
voltage of the conductors or leads. This arrangement is shewn in figure 2,
car No. 1 being shewn with its battery arranged for being charged, and car No. II
with its battery driving the motor, When charging the battery of car 1 both
halves B₁, B, of the same are connected in series with their respective motors D₁, D
so that the battery B₁, with its motor D₁ is connected up in parallel with the other
battery B with its motor D₂.
The current proceeding from the dynamo M through the conductor L is divided
in the car and passes not only through the motors D₁, D, but also through the
batteries B, B₂ for the purpose of charging the same. These batteries B, B,
however, only consume current corresponding to their difference of potential
at this period when the current strength or intensity is not very high whilst when
the batteries are connected up in parallel, as shewn in Figure 1, either the

page_text: battery takes so much current that the polarization set up thereby in com-
bination with the internal resistance raises the difference of potential of the
battery to the same level as the tension in the conducting wires or, in case the
current strength is too high for the battery, the current is reduced to the required
limit by switching on resistances whereby in both cases undue loss of energy is
bound to occur.
After the battery of car 1 has been charged by the above described method of
connection and before a place is reached where there are no external conductors
as shewn in connection with car II, the two halves B, B, of the battery are con-
nected together in series, the two motors D, D₂ being also connected together in
series, one of them D, being put in connection with the overhead con-
ductor L and the other D, with the earth connection E. The two half
batteries B, and B, now possess together exactly the average electromotive force
.and serve to maintain the tension of the circuit in the neighbourhood of the car,
approximately constant, giving, for instance, current to the motor when the car
begins to run and receiving current again when only, a small consumption of current
is taking place in the car.
When the car reaches a point at which there are no conductors the battery,
has to furnish alone the current for propelling the same and for this purpose
the connection may remain unaltered. In such cases, however, at points where
there are
no conductors the following method (illustrated by car No. III) of
connecting up can be employed, namely both half batteries B₁, B, and both
motors D, D can be connected up in parallel. In this case there is in the car
a difference of electrical potential equal to only half the voltage of the circuit.
When the battery is wholly discharged it can be again charged at first by coupling
the batteries and motors in the manner illustrated by car II Figure 2, the number
of cells being so chosen that this number multiplied by 2.2 is equal to the
voltage of the current flowing through the conductors. The charging operation
is completed by coupling each battery in series with its motor and the two pairs
(each composed of battery and motor) in parallel as shewn by car No. 1.
If it be desired to dispense with the equalizing action of the battery on the voltage
of the conductors as shewn by car II Figure 2, and which takes place when the
conductors at the power station or at any other point of the circuit are connected
up in parallel with a larger stationary secondary battery for equalizing the
tensions, I can employ instead of the two half batteries a single battery having
half the number of cells of double the size. By this means special advantages
are obtained, namely, the battery is on the whole cheaper and also lighter. This
method is illustrated in Figure 3. The stationary accumulator or secondary battery P
is connected in parallel with the dynamo M for generating the current.
In this case the motors 1), D, in the car I, which motors are coupled together
in parallel, are connected in series with the battery B. When the charging of
the battery B is completed and before the point is reached at which there are no
conductors the battery B is disconnected from the overhead conductor L as also
from the motors D₁, D, and the latter are coupled up in series as illustrated in car
No. II. If desired, however, the battery B can be connected up in parallel with
one of the two motors.
When the car arrives at a point unprovided with conductors the motors D, D
are arranged in parallel with the battery B as shewn in car III Figure 3.
By the employment of two motors of half the electromotive force I do not lose
the advantage derived from the use of two motors, that is to say, should one motor
be injured or become useless the other motor can be utilized for propelling the
In some cases as in car III Figures 2 and 3 this is also possible after the
connection with the injured motor has been broken.
car.
With the above described arrangement of accumulators or secondary batteries
5 in motor cars if it be arranged that the consumption of energy of the car, when
driven by the battery, is approximately the same as when driven by the dynamo

page_text: directly I can employ only one battery B and one motor, D. of half the electro-
motive force as illustrated in figure 4. When current flows from, the dynamo M
through the conductor L. the battery B.and motor are coupled up as shewn in car I
so as to charge the battery. When the battery propels the car on the portion of
its course having no conductors the positive and negative poles of the battery
are connected to the positive and negative poles respectively, of the motor
as indicated in car No. II. This arrangement also, has the advantage that
the battery is of low cost and of light weight in comparison with batteries of the
full electromotive force and having a double number of cells of half, the size. It
can, however, only be employed when, as above described, the consumption of
energy on the part, of the course having.conductors is approximately equal to that
on the part of the course without conductors.
رف
Cases may occur in which the battery is only required to propel the car over
street crossings, bridges or other approximately short distances at a slow speed.
In, such cases a motor (or two motors) designed, for the full voltage of the circuit
is employed and connected up as illustrated in Figures 3 and 4 whilst the battery
is designed for the half or for any other fraction of the voltage. The charging
of the battery in these cases only takes place at starting or when the cars are
running slowly (otherwise it would be necessary to employ resistances) and costs
practically, nothing as the energy if not so stored up would be transformed into
heat by resistance. For quicker journeys the battery is switched off and tho
motor is then only connected with the conductors according to the method shewn
in car II Figure 3. When the battery is required to propel the car over street
crossings, bridges, etc., the method of connection described with reference to car III
Figure 3 or car II Figure 4 is employed.
.
Having now particularly described and ascertained the nature of my said
invention and in what manner the sanie is to be performed, I declare that what
I claim is:-
In electrically propelled cars wherein batteries are employed for driving the
motors over distances not supplied with conductors in connection with a dynamo,
connecting up the battery, when the motor is supplied with current from the
external conductors, in series with the motor, substantially as, and for the purposes,
hereinbefore described.
.
WITC
SER way
TA
October
1001.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.