WO2010071539A1

WO2010071539A1 - Electric motor driven vehicle, production kit for producing an electric motor driven vehicle, and a method of producing an electric motor driven vehicle

Info

Publication number: WO2010071539A1
Application number: PCT/SE2009/000515
Authority: WO
Inventors: Thomas Bergfjord
Original assignee: Electroengine In Sweden Ab
Priority date: 2008-12-15
Filing date: 2009-12-15
Publication date: 2010-06-24
Also published as: WO2010071540A1

Abstract

The invention relates to a production kit comprising components to be installed in a vehicle, the vehicle comprising at least one drive shaft arrangement adapted for transmitting a torque to a single drive member for propelling the vehicle, the production kit comprising at least one electric motor comprising a stator and a rotor connectable with the drive shaft arrangement for applying the torque to the drive shaft arrangement, wherein the rotor is hollow so that at least a part of the drive shaft arrangement is extendable inside the rotor. The invention also relates to an electric motor driven vehicle and a method for producing an electric motor driven vehicle.

Description

Applicant: Electroengine in Sweden AB Our ref: P8556PC00

Electric motor driven vehicle, production kit for producing an electric motor driven vehicle, and a method of producing an electric motor driven vehicle

Field of the invention 10

The present invention relates to a production kit for producing an electric motor driven vehicle, an electric motor driven vehicle, and a method of producing an electric motor driven vehicle.

15 Prior art

Most vehicles in use today, so-called "conventional vehicles", are driven by fuel-burning engines. These engines are usually of the internal combustion type although a few vehicles use external combustion engines. In order to reduce the environmental impact of vehicles a

20 number of electric motor-driven vehicles (also called "electric vehicles") and hybrid vehicles (driven by the combination of any electric motor and a fuel-burning engine) have been conceived. These vehicles are produced in relatively small series which means that economies of scale have not been realised and they are relatively expensive when compared to conventional vehicles.

25

In an effort to reduce the cost of electric vehicles efforts have also been made to convert conventional vehicles to electric drive. US 3902565 describes an electric conversion arrangement for automobiles in which the internal combustion engine is removed and replaced by at least one electric motor and battery pack. The electric motor or motors are

30 connected to the original gearbox and transmission of the vehicle which simplifies the conversion and allows the driver of the vehicle to change gear as necessary. A problem with such a conversion is that the electric vehicle tends to have a low performance. Another problem is that electric vehicles quickly run out of energy, so that the effective range of a vehicle is severely limited.

35

Summary of the invention

One object of the present invention is to alleviate at least some of the problems of the prior art. 40

According to a first aspect of the invention this is achieved with a production kit comprising components to be installed in a vehicle, the vehicle comprising at least one drive shaft arrangement adapted for transmitting a torque to a single drive member for propelling the vehicle, the production kit comprising at least one electric motor comprising a stator and a rotor connectable with the drive shaft arrangement for applying the torque to the drive shaft arrangement and for propelling the vehicle, wherein the rotor is hollow, so that at least a part of the drive shaft arrangement is extendable inside the rotor. Alternatively, the production kit may also comprise one or more of the drive shafts.

According to a second aspect of the invention this is also achieved with an electric motor driven vehicle comprising at least one drive shaft arrangement adapted for transmitting a torque for propelling the vehicle, and at least one electric motor comprising a stator and a rotor connected with the drive shaft arrangement for applying the torque to the drive shaft arrangement and for propelling the vehicle, wherein the rotor is hollow and at least a part of the drive shaft arrangement is extended inside the hollow rotor.

According to a third aspect of the invention this is also achieved with a method for producing a vehicle comprising at least one drive shaft arrangement adapted for transmitting a torque for propelling the vehicle, the method comprising: installing an electric motor comprising a hollow rotor into the vehicle, and arranging at least a part of the drive shaft arrangement to extend inside the hollow rotor.

One advantage according to the aspects of the invention above is that due to that at least a part of the drive shaft arrangement may extend into the space inside the hollow rotor, the total length of the drive shaft arrangement together with the electric motor is shorter than if the drive shaft arrangement and electric motor are arranged one after the other. This is important since the space inside a motor compartment is limited, and the drive shafts need to be of a certain length, especially for land-based vehicles wherein the drive shafts need to allow a sufficient movement of the wheels due to vibrations and irregularities and bumps in the road, and also the electric motor needs to be sufficiently large in order to have an adequate performance. Hence the positioning of the electric motor and the drive shaft arrangement inside the motor compartment is simpler. Also, the drive shaft may be longer and/or the electric motor larger in relation to if the drive shaft were arranged completely outside the electric motor.

Another advantage of these aspects is that the same motor and/or production kit may be used for several different vehicles, since there is leeway in the distance that the drive shaft need to be inserted into the hollow rotor. This also allow for easier manufacturing, since the demands on the positioning of the electric motor within the motor compartment is lower. Preferably the drive shaft also comprises a universal joint for allowing angular movement of one end of the shaft in relation to the other end of the shaft, wherein the electric motor, rotor and interface system are designed so that the universal joint is at least partially positioned inside the hollow rotor.

The drive member is preferably a member arranged to exert a force relative to the environment of the vehicle in order to propulse the vehicle. According to one embodiment of the invention the vehicle is a land-based, motor-driven vehicle. Preferably the vehicle is a personal car, a bus, or a lorry. Preferably the drive member is then a drive wheel, making contact with the ground. Preferably the drive shaft arrangement is connectable with the drive wheel for transmitting a torque to the drive wheel for driving a rotation of the drive wheel and thus to propel the vehicle. In another embodiment the vehicle may be a vessel, such as a motor-driven ship or an aircraft, wherein the drive member preferably is a propeller, and the drive shaft arrangement is connectable with the propeller.

Preferably the production kit and hence the vehicle comprises an interface system for connecting the drive shaft with the rotor, which interface system is designed to allow connection of the rotor with at least two types of drive shafts. Thus the same production kit and interface system may be used for different types or models of vehicles. Preferably the interface system comprises an adapter plate comprising a concave inner surface for connecting with the drive shaft, wherein the adapter plate may connect with drive shafts of different thicknesses and/or lengths, and which are directed in different directions or angles.

According to one embodiment of the invention the electric motor and the rotor are adapted to be installed in the vehicle with a co-rotating connection between the rotor and the drive member via the drive shaft arrangement, so that the rotor, the drive shaft arrangement, and the drive wheel co-rotate with substantially the same rotational speed. Preferably the gearbox is also omitted or removed. Preferably the drive shaft arrangement is adapted to be connected with the drive wheel without a gear, or an intermediate gear or gear-box. The freed space may then be utilized for accommodating a larger energy storage, so that the range of the vehicle may be increased. Also, the freed space may then be utilized for receiving a larger electric motor, so that the speed and/or acceleration of the vehicle may be improved. Yet another advantage of omitting a gear or gear-box is that transmission losses due to the gear or gear-box are reduced. A gear-box typically has transmission losses due to the rotation and engagement of cogwheels within the gearbox.

According to one embodiment the electric motor is directly connected with the drive shaft, wherein transmission losses are decreased even further. Preferably the motor is directly connected to a half shaft connected with a drive wheel or wheels. Thus the electric motor may be connected to the drive shafts closer to the wheels. Thus the transmission, in this embodiment in the form of the drive shaft arrangement, may be shorter, wherein both transmission losses are reduced and the space taken inside the motor compartment may be decreased, so that there is even more room for the motor and energy storage. Preferably the drive shaft arrangement, or half-shaft, is connected directly with a wheel hub for attachment of a drive wheel.

According to one embodiment of the invention the rotor is rotationally fixedly connected with the drive shaft arrangement. Preferably the rotor is furthermore directly connected with the drive shaft arrangement. Preferably the drive shaft arrangement is also rotationally fixedly connected with the drive member, preferably directly connected with the drive member. The entire drive shaft arrangement is preferably arranged to rotate with substantially the same rotational speed, apart from possible vibration dampers, uptake of possible play in the drive shaft arrangement, and torsion in the drive shaft arrangement. A vibration damper may be a torsion spring or a viscous coupling. Preferably the difference in rotational speeds differ less than 10 % between the rotor and the drive wheel during stable conditions. More preferably, the rotational speeds differ less than 8 % between the rotor and the drive wheel during stable conditions. A stable condition may comprise a state of constant speed and torque.

According to one embodiment the production kit and hence the vehicle comprises a synchronous electric motor. Preferably the synchronous electric motor is designed to generate a maximum torque which is higher than or equal to 150 Nm. Preferably the synchronous motor is designed to generate a maximum torque which is higher than or equal to 250 Nm. Most preferably the synchronous motor is designed to generate a maximum torque which is higher than or equal to 300 Nm. The selection of maximum torque is of course dependent on the size and weight of the vehicle. Standard synchronous motors, which have been used in electrical vehicles up to the presentation of this application, have had a maximum torque of at the most about 50 Nm. The use of a stronger, non-standard synchronous motor allow a rotationally fixedly connection and/or a direct connection of the electric motor to the drive shaft, giving the advantages as stated above. Another advantage of using a non-standard, stronger, synchronous electric motor is that the torque generated, and hence the acceleration of the vehicle, is independent on motor speed, wherein a decent acceleration may be achieved at high speeds enabling safer overtakes. For the motors of the prior art connected to a gearbox, the torque is decreased at higher gears, meaning that it takes a longer time to achieve a temporary speed increase.

Preferably the synchronous motor is furthermore designed to rotate with a maximum rotation speed which is smaller than or equal to 2500 rpm. Preferably the synchronous motor is designed to rotate with a maximum rotation speed which is smaller than or equal to 2000 rpm. Most preferably the synchronous motor is designed to rotate with a maximum rotation speed which is smaller than or equal to 1800 rpm, preferably the rotation speed is about 1500 rpm. Since the motor is rotationally fixedly connected with the drive wheel the speed of the vehicle is determined by the rotational speed of the engine and the diameter of the drive wheel. By limiting the rotational speed of the electric motor the maximum speed of the vehicle is limited to safer speeds.

According to one embodiment the production kit and hence the vehicle comprises an electric motor which is a torque motor. Thus the electric motor may generate a torque while the rotor is immobile and without the motor being damaged. It is then possible to hold the vehicle immobile on, for example, an inclining surface. Preferably the motor is also a servo motor. It is then possible to position the rotor in a desired angle, which increases the precision when driving the vehicle. Preferably the one or more electric motor is a permanent magnet motor. Preferably the rotor is magnetized and comprises at least one permanent magnet. Hence it is not necessary to arrange brushes within the motor, which are prone to heavy wear and subsequent break-down, for example due to sparking, and also of contact issues with loss of functionality. Preferably the electric motor is also a synchronous motor, wherein the motor is frequency-controlled. This gives a better possibility to control both the motor speed and the torque in a simple and efficient manner. Preferably the one or more electric motor is a direct drive motor, wherein the rotor of the motor is directly connected with the drive shaft of the vehicle. Preferably the one or more electric motor is a permanent magnet synchronous direct drive torque servo motor.

In another embodiment the synchronous motor comprises at least two different windings arranged to be used at different motor speeds. Thus, the possible speed-range of the motor may be increased while maintaining the ability to generate a high torque.

Another embodiment of the invention comprises a converted conventional vehicle in which the engine and gearbox are omitted or removed, and replaced by one or more electric motors connected to one or more drive shaft of the vehicle. The production kit is then a conversion kit for converting a conventional combustion or hybrid vehicle comprising one or more drive shaft into an electric vehicle, the conversion kit comprising one electric motor for each of said one or more drive shaft. The method correspondingly comprises the steps of: a) omitting the installation of the conventional engine and gearbox and/or removing the conventional engine and gearbox from the vehicle; b) connecting an electric motor to each drive shaft exposed by the omitting and/or removal of the engine and gearbox. In one embodiment the method comprises the step of omitting the installation of the conventional engine and gearbox in a production line for the vehicle. In another embodiment the method may comprise removing the conventional engine and gearbox from a previously manufactured conventional vehicle. Preferably the at least one electric motor is adapted to be connected to the drive shafts already existing in the vehicle, and adapted to replace an omitted or removed conventional engine and/or gearbox. These drive shafts may become exposed upon removal of the original engine and gearbox.

One advantage of the invention is that the production of the vehicle is simplified. One reason for the simplification is that it is not necessary to do extensive rework of the already existing connections in the vehicle, in particular in regard of the drive shafts to the engine or motors. Thus, the combustion engine in the vehicle is replaced with an environmentally friendly alternative electric motor in a simple manner. The mounting of the new electric motor is almost as easy as replacing the combustion engine with another combustion engine of the same type.

Another reason is due to that it is not necessary to do any extensive changes in a production line for a conventional vehicle in order to change the production line into producing an electric vehicle. By omitting the step of installing the conventional engine and gearbox, the vehicle may be produced as usual in the production line. The production may then comprise connecting the electric motor either in a production step within the original production line, for example by replacing or changing the original engine installation step, or in a production step outside the production line, for example in an additional step following the production line or in a step in parallel with the production line.

According to one embodiment the invention comprises an interface system for connecting each drive shaft to its own electric motor. Preferably the interface system is arranged to allow connection of a drive shaft with a multitude of different dimensions and/or shapes to the electric motor. Thus, it is possible to use the same production kit for several different types and models of vehicles.

In one embodiment of the present invention the converted vehicle is a front-engined front- wheel driven vehicle in which the original engine and transmission have been replaced by two electric motors. Preferably, the rotor of one electric motor is connected to the left-hand drive shaft of the vehicle and the rotor of the second electric motor is connected to the right-hand drive shaft of the vehicle. Preferably, the two motors are individually controlled. Thus different functions such as anti-slip, anti-skid and others may be used by controlling the rotation speed of the motors and wheels.

For front engined, front-wheel drive vehicles and rear-engined rear-wheel drive vehicles a preferred embodiment of the invention comprises arranging two electric motors, one connected to the left-hand drive shaft and the other to the right-hand drive shaft of the vehicle.

Conversion kits for land vehicles in accordance with the present invention are suitable for front engined vehicles with front-wheel drive, front engined vehicles with rear-wheel drive, front engined vehicles with 4-wheel or all-wheel drive, rear engined vehicles with rear-wheel drive, rear engined vehicles with all-wheel drive and rear engined vehicles with front-wheel drive. Such kits may include one, two or more electric motors. Four or more wheel drive vehicles can use a combination of elements from the above arrangements for two-wheel drive vehicle.

According to one embodiment of the invention the conversion kit further comprises an electronic module adapted to connect the electric motors with an internal communication system in the vehicle. Preferably the electronic module also comprises a motor control module for controlling the torque, speed and/or position of the rotor in the electric motor. Preferably the method comprises providing the vehicle with an electronic module and/or a motor control module and interfacing the electronic module and/or the motor control module with an original data communication system in the vehicle.

According to one embodiment the conversion kit for converting a conventional vehicle to an electric vehicle comprises a number of major components and ancillary units which replace those used in a conventional in order to produce an electric vehicle with substantially the same functionality as the original conventional vehicle. Preferably the conversion kit comprises all necessary components needed to entirely replace the functions of the previous combustion engine, either directly or indirectly.

Preferably the original vehicle's engine and gearbox (together called the "drive package") are either omitted or removed, while the original half shafts (or prop shaft) can be retained in unmodified or modified form. Preferably, the removed or omitted components may be replaced by one or more electric motors, a battery pack and/or other electricity storage device and an interface system for connecting the one or more of the half shafts to the electric motor(s). Preferably the conversion kit is adapted so that the contents of the conversion kit may be accommodated within the original engine compartment of the vehicle.

According to a further embodiment the conversion kit or vehicle comprises an electricity storage for providing energy to the at least one or more electric motor. In one embodiment the electricity storage is e.g. a condenser. Preferably the electricity storage comprises a battery pack comprising at least one battery cell, preferably a plurality of battery cells. By providing a plurality of battery cells the cells may be positioned in different positions to shape the electricity storage to fit the shape of the engine compartment of a vehicle. Thus the same conversion kit may be more easily used in different vehicles.

Preferably the conversion kit or the vehicle comprises a battery charger which can convert mains electricity to DC electricity suitable for charging the batteries and any other electricity storage device. The vehicle may then be charged from a common household electric wall socket and may be driven on electric power only.

According to another embodiment of the invention the conversion kit and/or vehicle comprises a climate control system for controlling the climate in the internal passenger compartment, wherein the conversion kit is adapted to feed electric energy regenerated during braking to the climate control system, if the climate control system is active. The efficiency of recharging the energy storage is not 100 %. Hence, it is more energy efficient to use the regenerated electricity directly instead of wasting energy by first recharging the energy storage and then directly use the energy from the energy storage to energize the climate control system. The climate control system may for example comprise heating elements for heating incoming air or a cooling arrangement for cooling incoming air.

Further information regarding possible devices, kits, methods regarding conversion of conventional vehicles to electrically-driven vehicles is provided in the following detailed description.

Brief description of the drawings The invention is now to be described as a number of non-limiting examples of the invention with reference to the attached drawings.

Fig. Ia shows a schematic overview of a motor compartment of a vehicle comprising an electrical motor according to one example of the invention.

Fig. Ib shows an electric motor connected with a drive shaft arrangement in closer detail.

Fig. 2 shows a view from below of the electrical motor in fig. 1 mounted on a base frame.

Fig. 3 shows a side-view of an electricity storage pack and the electrical motor in fig. 1 provided with an interface system.

Fig. 4 shows a schematic view of the electrical connections between an electricity storage and the electrical motors.

Fig. 5 shows a production kit comprising a plurality of components according to one example of the invention.

Fig. 6 shows a diagram of a cooling system for the motor and a climate system for the passenger compartment according to one example of the invention.

Fig. 7 shows a method of producing a vehicle according to one example of the invention.

Fig. 8 shows another method of producing a vehicle according to another example of the invention.

Detailed description

In figs. 1-3, a motor compartment of a vehicle 1 is shown. The vehicle 1 comprises a frame 3 adapted to form part of the chassis of the vehicle, a drive shaft arrangement comprising drive shafts 7, and two wheels 5. The wheels 5 are connected with one drive shaft 7 each, in this case with a half shaft, and are each suspended on a shock absorber 9. In this example the vehicle 1 is a former conventional, combustion engine driven vehicle, meaning that the vehicle used to comprise or was designed to comprise an engine of the fuel-burning type, and a gearbox connecting the engine with the drive shafts 7 for transferring power to the wheels 5.

The vehicle in figs. 1-3 has in this example been converted into an electrically driven vehicle 5, wherein the original combustion engine, its power transmission and its gearbox, has been omitted or removed, and replaced by a production kit in the form of a conversion kit comprising one or more electric motors 11. In another example of the invention however, the production kit could equally well be installed in a conventional hybrid powered vehicle for replacing the combustion engine and the electric motor in the hybrid, or in a vehicle originally intended to be an electric vehicle.

The motors 11 are hollow and have annular, internal hollow rotors 17. In this example the electric motor comprises an annular, hollow rotor 17 with an inner diameter of at least 120 mm. Thus at least a part of the drive shaft arrangement may extend into and be positioned inside the rotor. The drive shaft must be sufficiently long in order to allow sufficient movement of the drive wheel, for example due to irregularities or bumps in the road. By using a hollow rotor and letting the drive shaft extend inside the rotor the drive shaft may be longer while the electric motor simultaneously may occupy a larger space within the motor compartment. Further, the freedom in the placement of the electric motor within the motor compartment is also improved. In order to allow even more flexing and movement of the wheels up and down, for example due to bumps in the road, the drive shaft further comprises one or more universal joints 18, arranged to allow a swinging movement between two shaft parts connected thereto. In this example one universal joint is arranged close to or at the end of the drive shaft being connected with the rotor. In this example one universal joint is at least partly arranged inside the hollow rotor. Thus the distance between the universal joint and the drive wheel is longer, wherein a turning in the universal joint gives a larger displacement of the drive wheel. In this example the universal joint is furthermore completely accommodated within the hollow rotor 17.

The production or conversion kit further comprises an interface system 15 for connecting the rotor of one motor to each drive shaft 7 exposed when the engine and gearbox of the original vehicle is removed. The interface system 15 is intended to rotationally fixedly connect the drive shaft of the vehicle with the annular hollow rotor 17, so that the drive shaft arrangement and the rotor co-rotate. The interface system is mounted directly against the existing drive shaft on each respective front wheel. In this manner the energy efficiency is optimized, and the need of a mechanical differential or reduction gear is eliminated, so that transmission losses decrease. The interface system 15 comprises an adapter plate 37 which is attachable at its periphery to the interior of the rotor at a position which is suitably deep inside the rotor 17 so that the power input end of the original drive shaft can be connected to it directly - thereby preserving the original geometry of the drive path.

In this example the converted vehicle 1 is a front-engined and front- wheel driven vehicle. The electric motors 11 are rotationally fixedly connected to the one or more drive shaft arrangements 7 of the vehicle. In this example the original engine and transmission have been replaced by two electric motors 11 , wherein the rotor 17 of one electric motor 11 is connected to the left-hand drive shaft of the vehicle, and the rotor of the second electric motor is directly connected to the right-hand drive shaft of the vehicle. The drive shaft arrangements 7 are furthermore arranged to co-rotationally connect the electric motors 11 with the wheels, so that the electric motors and the wheels co-rotate with the same rotational speed.

In this example, the replacement motors 11 in the conversion kit for converting the vehicle into an electric motor driven vehicle, and for replacing the combustion engine, are both complete and universal, wherein the motors 11 are adapted for mounting into several different models of vehicles. Hence the same production kit may be used for several vehicle models. In this example the original engine control system and exhaust system in the conventional vehicle are also be removed and the conversion kit comprises an electronic module 13 comprising a motor control unit. Furthermore, the conversion kit and the components therein, such as the motors and the electronic module, are directly connectible to existing actuation means or steering components in the vehicle. The production kit further comprises a battery pack or some other form of electrical storage 19, control units, replacement pumps and mounting means for supporting the motor and battery pack and mounting them to the vehicle. These components will be described in closer detail below in relation to fig. 5.

In this example the motor 11 is designed to generate a maximum torque which is higher than or equal to 150 Nm. In this example the synchronous electric motor 1 1 is designed to generate a maximum torque which is higher than or equal to 250 Nm. In this example the synchronous electric motor 11 is designed to generate a maximum torque which is higher than or equal to 300 Nm. In this example the synchronous electric motor 1 1 is furthermore designed to rotate with a maximum rotation speed which is smaller than or equal to 2500 rpm. In this example the synchronous electric motor 11 is designed to rotate with a maximum rotation speed which is smaller than or equal to 2000 rpm. In this example the synchronous electric motor 11 is designed to rotate with a maximum rotation speed which is smaller than or equal to 1500 rpm. The motor is thus adapted to have a low maximum number of revolutions and a high torque. One advantage of using an electric motor with high torque is that the torque is mostly constant regardless of the present rotation speed for the motor. Hence a constant, high acceleration is obtained at higher speeds as well as at low speeds. A combustion engine on the other hand is dependent on the gear, wherein the highest torque is obtained only at lower gears. Also, by providing two individually controlled motors, one for each drive shaft, the differential speed between the two drive wheels may be monitored, so that slipping may be avoided.

In this example the synchronous electric motor 11 is also a torque motor. Thus the electric motor may generate a torque while the rotor is immobile and without the motor being damaged. It is then possible to hold the vehicle immobile on, for example, an inclining surface. Preferably the electric motor is adapted to generate a torque while the rotor is immobile for an unspecified time period. Preferably the electric motor is a synchronous alternating current motor capable of applying a high torque from stand still of the vehicle. In this example the motor is also a servo motor. It is then possible to position the rotor in a desired angle, which increases the precision when driving the vehicle. In this example the electric motor 11 is a permanent magnet motor. In this example the rotor 17 comprises one or more permanent magnets. Hence it is not necessary to arrange brushes within the motor, which are prone to fast degeneration and subsequent break-down as well as contact problems. In this example the electric motor is also a synchronous motor. The electric motor 11 thus comprises a stator with at least one winding adapted to receive an alternating current. The design of the winding in combination with the alternating current induces a varying magnetic field affecting the rotor so that the rotor is rotated. Thus the electric motor is frequency-controlled. This gives better control both of the motor speed and of the torque generated. In this example the electric motor 11 also comprises at least two different windings arranged to be used at different motor speeds, so that the speed-range of the motor may be increased while maintaining a high torque. In this example the electric motor is a direct drive motor, wherein the rotor of the motor is directly connected with the drive shaft of the vehicle. In this example the one or more electric motor 11 is a permanent magnet synchronous direct drive torque servo motor.

The conversion kit, and thus the converted vehicle, also comprises an electricity storage 19 for supplying electricity to the electric motors as is better shown in fig. 3 and 4. In this example the electricity storage comprises a battery pack. The battery pack in turn comprises a plurality of battery cells 21. In another example the electricity storage may instead comprise a pack of capacitors, or a combination pack of capacitors and batteries, comprising both batteries and/or capacitor cells.

In this example the battery pack 19 comprises a number of battery cells, in this example 128 battery cells, each with a cell voltage of 3.2 V. The battery type is in this example lithium iron phosphate, but other types of battery cells may also be used. The battery pack is adapted to fill the physical space of the vehicle, and is adapted in number and size of the cells according to the weight of the vehicle.

The battery pack of 128 battery cells of Lithium gives a nominal voltage of about 410 V. The magnitude of 50 Ah per cell gives an energy content of about 20,5 kWh. This gives a standard vehicle a range of about 150 kilometers between charging. Lithium iron phosphate may cope with a current withdrawal of 10 CA, in this case 500 A. At the lowest voltage (about 2.6 V per cell) of about 330 V, this gives a maximum possible power of 165 kW. If the power use is to be increased one needs to increase the number of cells, increase the size of the cells, or use a more efficient type of cell.

The conversion kit and vehicle further comprises an electronic module 13 adapted to be installed inside the vehicle and to be connected with the internal data communication interface system 23 in the vehicle. The electronic module 13 may for example be positioned on top of the battery or electrical storage 19. In this example the electronic module 13 is adapted to be directly connected to the CAN-bus 23 of the vehicle or to some other type of I/O, in order for the conversion kit and the electronic module to be integrated into the rest of the vehicle's systems. In this example the electronic module is connected to all electrical systems of the vehicle through its CAN-bus.

The data communication interface system 23, such as the CAN communication bus is adapted for allowing communication with the vehicle's different control units. Typically the CAN-bus can transmit information from the original sensors arranged in the drive line and steering system concerning parameters such as wheel speed, steering angles, etc in order to calculate the speed differences between the wheels, activate anti-skid, traction control and anti-slip systems, control regenerative braking and integrate into the vehicle's safety systems.

Additionally signals can be transmitted to the vehicle's usual instrument panel so that the driver's environment is maintained intact following the conversion and incorporation of the conversion kit into the vehicle. In this example the electronic module is adapted to allow communication with the instrumental panel so that the speed indicator, speedometer, temperature displays, etc. work as usual. The electronic module 13 is further adapted to present signals so that the fuel consumption measuring device shows the remaining battery capacity and warns as usual when the remaining driving distance reaches a certain threshold. In this case the electronic module is further adapted to limit the maximum torque of the motors to further call for the attention of the driver. This does not necessarily make the car go slower, but decreases the possible acceleration markedly.

The electronic module 13 may furthermore communicate with other systems in the vehicle by the CAN-bus or I/O. Received signals may for example comprise information on: Wheel speeds, steering angle, throttle or acceleration, brakes or braking action, handbrake, heating need in the compartment, air condition, ignition locking, door contacts, warning systems, signal from box with gear control, speed control, and/or traction control (ABS, ESP). In essence, any signals in use in a conventional vehicle may be received. Emitted signals may, for example, comprise information to the instrumental panel, the cooling fan, the rear lights and/or the climate system.

The electronic module 13 also comprises a motor control unit 25 adapted for controlling the torque and speed of the two electric motors 11. The motor control unit is connected with the original CAN-bus of the vehicle for transmitting control signals to the electric motors. In this example the motor control comprises frequency modulation control of the electric motors. In this example the motor control comprises pulse-width modulation (PWM) control of each motor's torque and speed of rotation. By using PWM control the speed of a motor can be checked and changed thousands of times per second (i.e. at kHz rates). This means that anti-lock braking, anti-slip and traction control functions may be improved over the current mechanical/hydraulic systems which work at speeds in the order of single digit or at most low double digit Hertz rates. Each motor 11 can be controlled individually thereby providing locally adapted braking effect. In this example the motor control is also adapted to control the motors so that the differential speed of the wheels is limited. Thus an anti-spin or antiskid system is achieved, which reminds of a four wheel drive without any mechanical components.

In this example the motor control module 25 adapted to control the rotational speed of one electric motor and its associated drive wheel based on the rotational speed of the other drive wheels and/or electric motors. In this example the motor control module is adapted to control the rotational speed of one electric motor based on the present steering angle. In this example the motor control module controls the rotational speed of an electric motor controlling a wheel on one side of the vehicle to differ from the rotational speed of a motor controlling a wheel on the other side of the vehicle, so as to accommodate for the difference in travelling distance for the wheels when turning the vehicle.

Since the vehicle has electronic differentiation, the motor control module is further easily arranged to control the rotational speeds of the electric motors based on the wheel speeds and the steering angle, so that the difference in rotational speeds does not exceed the necessary difference for achieving the difference in travelling distance for the wheels. In this example, during start-up of the vehicle, the motor control module is arranged to control the electric motors to have rotational speeds differing less than 8 % from each other, to avoid that one wheel slips and rotates with high speed, while the other remains still. Hence one driving wheel will not slip and rotate with a high speed while the other remain still, as is sometimes the case with a mechanical differentiation. This also improves the accessibility considerably in relation to a traditional differential lock, since all driving wheels always work optimally irrespective of the footing for each wheel. The motor control module is also easily arranged to control the electric motors so as to incorporate features such as anti-skid and ABS-braking.

If the original vehicle had a hydraulic servo steering pump then the conversion kit may also comprises an electric servo steering pump 27, as depicted in fig. 5, and which replaces the original pump. The electronic module 13 also comprises a steering module adapted to control the steering servo pump 27. The electric steering servo pump may be connected to hoses leading to an adapter, which in turn is connected with the existing steering servo connections of the vehicle. The original cooling system for the hydraulic oil remains from the conventional vehicle. Since servo steering is controlled by torsion the electric servo pump is in this example arranged to operate at a basic mode for maintaining a desired pressure, and to increase the speed of rotation intermittently. This saves a lot of energy in relation to a servo pump of the band driven type.

The steering module may also generate a variable signal to the motor control unit determining the torque/speed of the motors. The steering module also stores error codes and operation times, in order to provide the information for analysis during a following service visit. Any cables (from the motors) connected with the electronic module 13 may be positioned inside the space of the motor or in a separate box. The conversion kit and vehicle further comprises a charger 29 for charging the electric storage. The charger 29 charges the electrical storage devices from mains electricity, such as a power grid, or from other sources of electricity. The charger 29 is in this example adapted to receive different types and sizes of currents from different types of power grids. It may be integrated in the electronic module and the power grid connection may be 230 V, 400V or any other voltage depending on the standard in different countries, and may receive currents typically in the order of 10 A, 16 A, or 32 A. Different connection cables may be provided for use with different currents and voltages, respectively. The cables may comprise codes giving the charger information about which current magnitude is present. This charger may result in a charging time (to 80 % charge) of 1-8 hours.

The electronic module 13 also comprises a DC-DC converter for converting the battery pack's voltage to 12V in order to provide power to the vehicle's ordinary 12-V system. This is of a switched-type and outputs the current that the existing electric systems of the vehicle 1 needs. The converter receives its current from the battery pack 19 and converts the current into 12 V. The initial power is in this example 1.5 kW. In case the vehicle is a lorry the converter may instead convert the current to 24 V, to fit the predominant systems in this type of vehicles.

The electronic module 13 further comprises a DC-AC converter which is able to convert the battery voltage of 380 V or more directly to a mains voltage such as 230 V 50 Hz AC which can be supplied to a standard domestic socket on the vehicle. The wiring to the socket can be dimensioned to allow currents of up to 10 Amps, or more preferably 16 Amps, thereby allowing mains-voltage electrical equipment such as electric tools to be powered directly from the vehicle. A 110 V 60 Hz (or other mains voltage) conversion of the battery voltage can be provided in addition to, or instead of, the 230 V 50 Hz AC conversion. The converters described may also work with a different number of cells.

The conversion kit or vehicle comprises a braking sensor 31. The braking sensor 31 may be arranged on the brake pedal of the original conventional vehicle. The braking sensor 31 gives a signal to the motor control unit in the electronic module 13 when the first part of the brake pedal is depressed. In this range the motors 11 are operated as generators, so that the kinetic energy of the vehicle is returned to the vehicle as electric energy. If a further braking force is necessary, for example during a further depression of the braking pedal, the regenerative braking remains in cooperation with the existing mechanical braking system of the vehicle. A further braking force may also be necessary if the systems for anti-spin or anti-skid are activated. If a differential wheel speed is detected during regenerative braking only, the torque of the motors 11 will be continuously adapted to the differential speed relative to the surface under the wheel for optimal braking action (6-8% slip). The regenerated electric energy is conducted to the charger 29, and the charger is correspondingly arranged to receive the regenerated energy from the electric torque motors during the braking. The charger 29 then charges the electrical storage 19 and the battery cells 21 with the regenerated energy.

The production kit further comprises a base frame 33, also shown in figure 5, for fitting the electric motors 11 to the vehicle 1. The base frame 33 is adapted to be connected with the original frame 3 of the vehicle 1, as shown in figs. 1-3. In this example the base frame 33 comprises a square shaped frame provided with a central beam, dividing the frame into two parts, wherein one motor is mounted in each part. The conversion kit further comprises one or more universal mounting plates 35, shown in fig 5, for holding components onto the base frame 33. The universal mounting plates 35 comprises a plurality of mounting holes at several in different positions, so that the mounting plates 35 may be used with several different types of vehicles, both with mounting holes provided in the original body of the vehicle and with different components of the production kit, including the base frame 33. The base frame 33 is similarly provided with a plurality of predrilled holes which permit one design of the base frame 33 to be used for more than one vehicle model.

In this example all parts of the conversion kit may be mounted onto the base frame 33, either directly or indirectly on components already mounted on the base frame 33. In particular the base frame 33 is adapted for mounting the electrical storage 19, including the battery cells 21, and the motors 11, onto the base frame. Most components being part of the conversion kit are thus fixedly mounted on the base frame 33 with universal mountings fitting many standard vehicles. The battery pack is attached to the base frame 33 and positioned so that the base frame 33 with components can be accommodated inside the engine compartment of the vehicle once the original drive package has been removed.

In figs. 1-3 and 5 the interface system 15 for connecting a drive shaft to the rotor of a motor is shown. In this example, the interface system 15 is adapted to rotationally fixedly connect the drive shaft to the rotor. The interface system 15 is arranged inside the hollow rotor 17 and comprises an adapter plate 37 provided with a concave, cone shaped inner surface which adaptively fits with the outer surface of a drive shaft and connects the drive shaft to the electric motor. Thus the same motor 11 and interface system 15 may be used for several different types of drive shafts. Furthermore, the motor may fit with the drive shaft regardless of the previous mounting angle of the combustion engine, and thus the present angular direction of the drive shaft, and regardless of the length of the drive shafts, since for longer drive shafts the connection is simply moved further inside the hollow rotors. Thus the motors may be accommodated at the same positions in the base frame 33 for several different configurations of the drive shafts, regardless of different distances between the two closest ends of the two front drive shafts. In another example the adapter plate 37 of the interface system 15 may be oriented and connected with the rotor 17 in the other direction, so that the outer cone shaped surface of the adapter plate is exposed and connected with the drive shaft instead of its inner surface. In particular, the motor and interface system 15 then also fits vehicles in which the distance between the existing drive shafts is less than the common width of the motors. Thus the interface system may fit vehicle both with large distances between the drive shafts and splines, and vehicles with small distances between the drive shafts and flanges. When connecting to splines the interface system is also provided with a container with a lubricant and with a connection for fitting with the existing bearing. The interface system is adapted for universal use in order to fit several different types and models of vehicles, in particular with different types of cars.

In this example the electric motors are adapted for liquid cooling as shown in fig. 6, and excess heat in the cooling liquid can be used for heating the passenger compartment of the vehicle. The electric motor control unit in the electronic module 13 can also be adapted for liquid cooling and the excess heat can be used for heating the passenger compartment of the vehicle. If the original vehicle had an engine-driven water pump then the conversion kit may, if liquid cooling of the motor(s) and/or motor control unit is needed, comprise an electric water pump 39, as shown in fig. 5, which replaces the original pump. In order to be able to use just one water pump it is preferable to position the motor control units close to the electric motors 11 and in fluid connection with their cooling systems. Thus the electronic module 13 may also be cooled by the original cooling system of the vehicle. In case the vehicle is originally intended to be an electric vehicle, the electric vehicle would of course also comprise such an electric water pump 39.

The energy for heating the passenger compartment is thus extracted in the first instance from the cooling liquid used to cool the motors 11 and their control unit(s) 13. However, since the electric motors 11 and the electronics 13 are very energy efficient, the excess heat energy generated will not be sufficient for heating the passenger compartment during very cold conditions. Hence, the heating of the passenger compartment can be complemented by an electrical heater 41 or a heat pump. In this example an electrical heater for heating the air to the passenger compartment is arranged inside the air channel to the passenger compartment. The electric heater is positioned downstream of the ordinary heat exchanger with the cooling system, wherein the electric heater will not heat the cooling liquid passing the motors, but only the air to the passenger compartment. The electrical heater is self regulating, wherein the electric heater heats the air depending on the heating needs, to a desired temperature.

In order to further save energy, the conversion kit and/or the vehicle is adapted to supply the regenerated electricity, for example from braking the vehicle, directly to a component in the vehicle, for example to the electric heater for heating the passenger compartment. Since some energy is wasted while charging the battery, it saves energy to direct the regenerated electricity directly to a component in the vehicle. In particular, it saves energy to direct the regenerated electricity to the electric heater for heating the air in the passenger compartment during cold conditions. This is also allows a less expensive vehicle, since electronics for controlling the recharge of the battery from regenerated electricity may be excluded.

In order to save energy even further the invention comprises limiting the movement of a recirculation damper controlling the recirculation of the air in the passenger compartment, so that a part of the air is recirculated into the passenger compartment. Thus the heat energy in the recirculated air is returned to the passenger compartment.

In this example the original conventional vehicle comprises an air conditioning system comprising a cooling compressor. During conversion of the conventional vehicle the cooling compressor is retained, however the conversion kit and the converted vehicle comprise an auxiliary electrical motor 43 which is mounted directly onto the shaft of the compressor. The auxiliary electrical motor is adapted to drive the compressor according to the current cooling needs.

A conventional vehicle usually comprises a circulation pump be driven by the combustion engine by use of a belt, and arranged to create a circulating flow of the cooling liquid. Hence, the conversion kit and vehicle comprises an electric circulation pump 39, shown in fig. 5, which is connected with and controlled by the electronic module 13 for replacing the original circulation pump. The replacement circulation pump may be mounted to the base frame 33 and may further comprise hoses connecting the circulation pump with the original cooling system with use of adapters. The electric circulation pump is in this example controlled by the electronic module 13 based on the temperature in the electric motor 11 and of the heating need in the passenger compartment. Thus the circulation pump is active only when needed, in difference to the belt-driven circulation pump of the prior art.

The air conditioning or heating system of the vehicle thus functions normally after the conversion. However the conversion gives the advantages of better control as described above. Furthermore the electronic module 13 is arranged to control the initiation of preheating of the vehicle dependent on information of intended use from a driver of the vehicle and on information about for example concerning a possible connection to the power grid, available energy in the electrical storage and outdoor temperature. The control of the pre-heating system may be carried out with a mobile phone by the user, and/or time periods for pre-heating may be predefined.

The conversion kit and vehicle also comprises control circuits in the electronic module 13 for providing driving mode selection. In this example the driving mode selection is connected to the original gear control. Thus, the conversion kit comprises electrical connections for adapting the original gear control with the driving selecting circuits. The communication may be carried out through the CAN-bus 23. The driving mode selection circuit is arranged to provide a first, neutral driving mode, in which the vehicle remain immobile, a second driving mode for forward motion, and a third driving mode for backward motion, as normally provided for conventional vehicles with automatic gear.

If the original vehicle had an engine-powered vacuum pump for supplying vacuum to the brakes, then the conversion kit comprises an electric vacuum pump 45 which replaces the original pump. The vacuum pump 45 is in this example mounted onto the battery box. The electric vacuum pump comprises a hose connected to an adapter, which in turn is connected with the original connection for vacuum of the converted vehicle. The vacuum pump is controlled by a vacuum switch, wherein the vacuum pump 45 is operational only during need, which saves energy.

Charging stations supplying power to the vehicle may be arranged wherever vehicles often are parked, for example in connection with parking lots. The charging station may also comprise a guide for guiding a contact unit provided on the vehicle into electrical contact with the charging station. The conversion kit or vehicle may comprise a contact unit mounted onto an arm, extending the contact unit from the vehicle, preferably so that the contact unit becomes visible by the driver of the vehicle. Thus, the driver may drive the vehicle, so that the contact unit is guided by the guide into electrical contact with the charging station, without having to leave the vehicle. In this example the arm also comprises a spring, preferably a gas operated spring, for dampening the impact during the connection. When leaving the charging station, the driver correspondingly only need to drive backward, and the contact unit detach from the charging station and is retracted automatically.

The electronic module also has an integrated GPS/GSM/3G-circuit arranged to transmit a notice to a service provider in case of a failure. Hence information is directly transmitted to the service partner who may carry out appropriate measures. The GPS-circuit is also arranged to provide protection from theft, in that the owner or service provider may inquire for the position of the vehicle from an external communication link. The electronic module is further arranged to transmit a notice, for example to the owner of the vehicle or to a service provider or server, in case of a service need. A server may then be adapted to automatically book time for a service visit.

Suitable vehicles for conversion or production comprise cars, such as private cars, and light lorries. In particular, light lorries may be provided with larger battery packs for extended range. The vehicle may also be provided with a voltage conversion circuit arranged to provide an alternating current for driving external equipment. For example, the vehicle may be provided with a tool voltage supply for supplying electricity to electrical tools used in the vicinity of the vehicle. Hence the vehicle may be used by workers both for transportation and as an energy source for tools, such as nail-guns etc. The vehicles may be provided with tool voltage supplies with a voltage of 230 V AC for handheld electric tools, or with 400 V AC for heavier equipment. The vehicle could also be provided with a direct current supply for driving tools or equipment adapted for direct currents. If the vehicle comprises four wheel drive, an additional motor may be connected with the prop shaft for driving the second pair of wheels. In case the original vehicle comprises a final gear provided in between the prop shaft and the driving wheels, the motor may be provided with a winding for higher rotational speed and lower torque, so that the gear may remain in the vehicle.

When driving the converted vehicle is started in the same manner as before conversion. When ignition is turned on the instrument panel acts as usual, though some information, for example on self-diagnosis, may be removed. When turning the starting key to the start position or when a starting button is pressed the system is indicated as active. The indication in the instrument panel depends on the design of the different car models. In car models with text based or a graphical display this is shown with a text or a symbol.

In neutral mode the brake is actuated (as on automatic cars) and driving direction is selected. The system then keeps the car in position until movement of the accelerator. The accelerator controls the torque of the motor, meaning that the electric drive feels as a conventional vehicle with a combustion engine. Since the torque of the motor is very large already at the beginning the current torque is limited for each respective motor so that the speed of the driving wheel does not exceed 8 % of the speed of the car, which is the breakpoint for optimal grip, after which further acceleration is unobtainable.

One example of the content of a conversion kit according to the invention comprises the following components:

Fixedly mounted parts

Base frame

2 or more electric torque motors

Battery box comprising individually connectible battery cells with associated protective caps

Electronic module

Drive electronics

Possibly an electric circulation pump

Accessories

Interface system

Universal mountings

Control computer program

Electric servo pump Electric vacuum pump

Electric auxiliary heater

Electric motor for driving cooling compressor

Electric cables with contacts adapted to vehicle type or model Adapter for possible hydraulics Adapter for cooling water system Adapter for vacuum

In fig. 7 one example of a method according to the invention is shown. The method comprises producing a new electrical vehicle in a production line. In this example the method comprises producing a new electrical vehicle in an original, but modified, production line for producing conventional vehicles. This method may for example be carried out in a production facility or manufacturing plant for producing vehicles, in particular land-based vehicle and most particularly cars or trucks.

In a first group of production steps, collectively referenced as 50 in fig 7, a vehicle is produced in a conventional manner up to the point of installation of the combustion engine and/or transmission comprising the gearbox. In this example, the group of steps 50 comprises substantially the same steps as the steps when producing a conventional vehicle in the production line. However, the method omits the steps of installing the combustion engine, the gearbox, and any components dependent on the combustion engine, such as belt driven pumps and the like.

In a second group of production steps, collectively referenced as 51 in fig. 7, the method comprises preparing the vehicle for installation of a production kit for producing an electric motor driven vehicle. This group of steps 51 may comprise for example adapting electrical or fluid connections, mountings or similar to the components in the production kit.

The method further comprises turning the vehicle into an electrical vehicle in a third group of steps 53. The group of steps 53 thus comprises installing a production kit comprising at least one electrical motor into the vehicle. In this example the electric motor comprises a hollow rotor, wherein the method further comprises arranging at least a part of the drive shaft arrangement to extend inside the hollow rotor. In this example the method comprises connecting an inner surface of the hollow rotor with the drive shaft arrangement by use of an adapter plate. In this example the method also comprises connecting the drive shaft arrangement with the rotor so that at least a part of the drive shaft is arranged inside the hollow rotor. In this example the drive shaft further comprises at least one universal joint for allowing angular movement of one end of the shaft in relation to the other end of the shaft, wherein the method comprises connecting the drive shaft arrangement to the hollow rotor so that the universal joint is at least partially positioned inside the hollow rotor. In this example the drive shaft arrangement and the electric motor are arranged so that the universal joint is completely accommodated inside the hollow rotor.

The method further comprises installing the production kit so that the electric motor is installed in the vehicle with a co-rotating connection between the rotor and the drive wheel via the drive shaft arrangement, so that the rotor, the drive shaft arrangement, and the drive wheel co-rotate with the same rotational speed. In this example, the electrical motor is installed so that the rotor is rotationally fixedly connected with a drive shaft, preferably directly connected with the drive shaft. The drive shaft in turn is co-rotationally connected with at least one drive wheel of the vehicle. Thus there will be no gearbox arranged in between the electric motor and the drive wheel, wherein power loss in the transmission is decreased.

In this example the method comprises installing an electrical motor having a high torque and a low maximum speed of revolutions. In this example the maximum speed of revolution is less than or equal to 2000 rpm, preferably less than or equal to 1700 rpm. Preferably the torque is also higher than or equal to 150 Nm, preferably higher than or equal to 250 Nm, and most preferably higher than or equal to 300 Nm.

In this example the third group of steps also comprises installing a production kit comprising an electricity storage, an electronic module, a base frame and/or other components as are described above.

The method further comprises additional manufacturing steps, such as connecting a 12 V output from the electronic module and/or electricity storage to the existing battery cables in the vehicle, connection of hoses to the different pumps in the kit and connection of other electrical or communication connections as described above. In particular the method comprises connecting the electronic module 13 to the internal data communication system and/or CAN-bus of the vehicle. The method also comprises installation of an external connection for receiving external electrical power for charging of the electrical storage.

Hence an electrical vehicle is produced by the method, which has been produced with the use of a conventional production line for producing conventional vehicles of the combustion or hybrid type. The first, second and third group of steps may be carried out in the same production cells as for a conventional vehicle. The second and third group of steps may for example be carried out in the same production cells as for the installation cells for the combustion motor. The second and third group of steps may however also be carried out in production cells arranged outside and/or in parallel with the conventional production line.

The first, second and third groups of production steps may furthermore be mixed with each other so that some or all of the adjustment steps for preparing the vehicle for electric propulsion, and installation steps for converting the vehicle into an electric vehicle are carried out at the same time or interspersed with the conventional production steps. Furthermore, part of the steps in the first and second groups may also be carried out after completion of the steps in the third group. Furthermore, steps for producing a conventional vehicle may also be omitted and/or delayed to a later stage of the production of the vehicle, to better fit the production of the electrical vehicle. In fig. 8 another example of a method according to the invention is shown. The method comprises conversion of an already produced conventional vehicle into an electric vehicle, and may for example be carried out in a repair shop or similar.

In a first group of conversion steps 61 the method comprise removing original components from the vehicle, which are not to remain in the new converted electrical vehicle. In particular, the method comprises removal of the original combustion engine. In this example the method also comprises removal of parts of the transmission of the vehicle, in particular removal of the gearbox from the vehicle. In addition the method may comprise removal of one or more of the exhaust system, the silencer, a catalytic converter, 12 V- battery, intake pipe, circulation pump, servo pump, and vacuum pump. The method may also comprise disconnection of one or more of the hoses for cooling liquid, the hoses for steering servo, the hoses for vacuum, the connections to the engine, the connections to the driving mode selector or gear lever, and the connections to the fuel tank. The first group of steps 61 may also comprise additional steps as described in the second group of production steps 53 in the method as shown in fig. 7.

In a following group of conversion steps 63 the method comprises installation of a conversion kit for converting the conventional vehicle into an electrical motor driven vehicle. The second group of steps 63 may for example contain the same or similar production steps as those in the third group in the method as shown in fig. 7.

The invention is not limited to the embodiments shown, which can be varied freely within the framework of the following claims. In particular, the features of the various embodiments and examples described may be freely combined with each other in order to reach additional embodiments, which are all considered part of the scope of the present application.

Claims

1. A production kit comprising components to be installed in a vehicle, the vehicle comprising at least one drive shaft arrangement adapted for transmitting a torque for propelling the vehicle, the production kit comprising an electric motor comprising a stator and a rotor for generating and applying said torque to the drive shaft arrangement, characterized in that the electric motor and rotor are adapted to be installed in a vehicle with a co-rotating connection between the rotor and a drive member via the drive shaft arrangement, so that the rotor, the drive shaft arrangement, and the drive member co-rotate with the same rotational speed, and in that the rotor is hollow so that at least a part of the drive shaft arrangement is extendable inside the rotor.

2. A production kit according to claim 1, characterized in that the electric motor is adapted to be installed in a vehicle comprising a drive shaft arrangement arranged to transmit a torque and a rotation from the rotor to a drive member without a gear-box.

3. A production kit according to claim 1 or 2, characterized in that the production kit comprises at least two electric motors, each adapted to be connected with a single drive shaft arrangement for driving a single drive member.

4. A production kit according to claim 1, 2 or 3, characterized in that the electric motor is a synchronous motor designed to generate a maximum torque which is higher than or equal to 150 Nm, preferably higher than or equal to 250 Nm, and most preferably higher than or equal to 300 Nm.

5. A production kit according to one of the claims 1-4, characterized in that the electric motor is a torque motor, and the electric motor is able to generate a torque with its rotor positioned immobile in a controlled position.

6. A production kit according to one of the claims 1-5, characterized in that the electric motor is a synchronous alternating current motor capable of applying a high torque from stand still.

7. A production kit according to one of the claims 1-6, characterized in that the electric motor and rotor are adapted to be installed in a vehicle in which the drive shaft arrangement and the drive member co-rotates, and are further adapted so that the rotor and the drive shaft arrangement form a co-rotating connection.

8. A production kit according to one of the claims 1-7, characterized in that the production kit comprises the drive shaft arrangement, wherein the drive shaft arrangement and the electric motor are adapted to be installed in a vehicle with a co-rotating connection between the rotor and the drive member via the drive shaft arrangement

9. A production kit according to claim 8, characterized in that the drive shaft arrangement is adapted for transmitting a torque to a single drive member for propelling the vehicle

10. A production kit according to claim 8 or 9, characterized in that the production kit comprises at least two drive shaft arrangements, adapted to drive a single drive member each, and at least two electric motors adapted to be connected with a single drive shaft arrangement each.

11. A production kit according to claim 8, 9 or 10, characterized in that the drive shaft comprises at least one universal joint for allowing angular movement of one end of the shaft in relation to the other end of the shaft, wherein the electric motor is adapted to allow a connection with the drive shaft arrangement so that the universal joint is positioned inside the hollow rotor.

12. A production kit according to one of the claims 1-11, characterized in that the drive member is a drive wheel.

13. A production kit according to one of the claims 1-11, characterized in that the drive member is a propeller.

14. An electric motor driven vehicle comprising at least one drive shaft arrangement adapted for transmitting a torque to a single drive member for propelling the vehicle, and at least one electric motor comprising a stator and a rotor connected with the drive shaft arrangement for generating and applying said torque to the drive shaft arrangement, characterized in that the drive shaft arrangement and the electric motor are connected with a co-rotating connection between the rotor and the drive member via the drive shaft arrangement, so that the rotor, the drive shaft arrangement, and the drive member co-rotate with the same rotational speed, and in that the rotor is hollow so that at least a part of the drive shaft arrangement is extended inside the rotor.

15. A method for producing an electric motor driven vehicle, the method comprising:

- installing at least one drive shaft arrangement in the vehicle, the drive shaft arrangement being adapted for transmitting a torque to a single drive member for propelling the vehicle, and to be connected with the drive member so that the drive member and drive shaft arrangement co-rotates,

- installing at least one electric motor comprising a stator and a hollow rotor into the vehicle,

- arranging at least a part of the drive shaft arrangement to extend inside the hollow rotor, and

- connecting the rotor with the drive shaft arrangement with a co-rotating connection, so that the electric motor may generate and apply said torque to the drive shaft arrangement, and so that the rotor, the drive shaft arrangement, and the drive member co-rotate with the same rotational speed.