electric bike

Abstract

The invention relates to an electric bicycle comprising a drive unit, a power supply device for supplying power to the drive unit, and a control unit configured to control the drive unit. It is proposed that the electric bicycle, in particular the control unit or the power supply device, comprise an estimation unit configured to determine a performance characteristic, and that the control unit be configured to control the drive unit based on the performance characteristic.

Description

Prior ArtElectric bicycles with a drive unit are already known, which are supplied with energy via an energy supply. In addition to a state of charge that is too low, overheating of the battery pack can also lead to a reduction or a omission of the assistance power in the case of an electric bicycle.Disclosure of the InventionThe invention relates to an electric bicycle having a drive unit, having an energy supply device for supplying energy to the drive unit, and having a control unit which is designed to control the drive unit. It is proposed that the electric bicycle, in particular the control unit or the energy supply device, has an estimation unit which is designed to ascertain a performance characteristic variable, and the control unit is designed to actuate the drive unit on the basis of the performance characteristic variable. Advantageously, the control of the electric bicycle can thereby be optimized and a premature shutdown of the drive unit due to an excessively high temperature and / or an excessively high power consumption can be prevented.The drive unit of the electric bicycle has, in particular, an electric motor. The electric motor is preferably designed to assist the driver. The electric motor can be designed, for example, as a hub motor or as a middle motor. The control unit of the electric bicycle is assigned to an electronics of the electric bicycle. The electronics can be integrated into the electric bicycle as a detachable bicycle component, for example as a board computer. The control unit can be configured to control or regulate further bicycle components, such as an ABS device, an electronic bicycle shift, a display unit, a lighting unit or the like, in addition to the drive unit.The energy supply device is in particular designed as a rechargeable battery pack, preferably as a replaceable rechargeable battery pack. The battery pack is in particular part of a system which is composed of the battery pack and the electric bicycle, wherein the electric bicycle is supplied with energy via the battery pack during operation. The replaceable battery pack is preferably designed to be detachable with the consumer without tools. Alternatively, it is also conceivable for the battery pack to be fixedly attached or integrated in the housing of the electric bicycle. A tool-free separation is also to be understood here as a separation via a lock, for example a bicycle lock. The lock can be designed to be actuatable, for example, via a key or an electric actuator. The battery pack is in particular configured such that it can be connected to a charging device for charging the battery pack. Alternatively or additionally, the battery pack can also be designed in such a way that it can be charged in the state connected to the electric bicycle.The battery pack comprises in particular a housing. At least one battery cell is arranged in the housing of the battery pack. The housing of the battery pack is preferably designed as an outer housing. The battery pack, in particular the housing of the battery pack, can be configured to be detachably connectable or fixedly connected to the electric bicycle and / or a charging device via a mechanical interface. The housing preferably has at least one housing part which is designed as an outer housing part. The outer housing part in this case delimits the battery pack on the outside and can be touched by a user. In addition, the housing can have at least one inner housing part which is completely surrounded by the at least one housing part. The two housing parts are preferably connected to one another in a force-fit and / or form-fit manner. This can be effected, for example, via a screw connection, a clip connection or another type of connection known to the person skilled in the art.The battery pack can be connected to the electric bicycle in a force-fit and / or form-fit manner via a mechanical interface. The mechanical interface advantageously comprises at least one actuating element, via which the connection of the battery pack to the electric bicycle and / or to the charging device can be released. The actuating element can be designed, for example, as a lock, a button, a lever or as a button. The actuating element can be arranged on the battery pack or on the electric bicycle. In addition, the mechanical interface can comprise guide elements for guiding the battery pack during the connection process and / or centering elements for centering the battery pack during the connection process.In addition, the battery pack has at least one electrical interface, via which the battery pack can be electrically connected to the electric bicycle and / or to the charging device. The battery pack can be charged and / or discharged, for example, via the electrical connection. Alternatively or additionally, it is also conceivable that information can be transmitted from the battery pack to the electric bicycle and vice versa via the electrical interface. The electrical interface is preferably designed as a contact interface in which the electrical connection is effected via a physical contact of at least two conductive components. The electrical interface preferably comprises at least two electrical contact elements. In particular, one of the electrical contact elements is designed as a positive contact and the other electrical contact element is designed as a negative contact. In addition, the electrical interface can have at least one additional contact which is designed to transmit additional information to the electric bicycle and / or to the charging device. The additional contacts can be designed as signal contacts, coding contacts, temperature contacts, bus contacts, etc. The electrical contact elements can be designed, for example, as resilient contact elements in the form of contact tulips or as flat contacts in the form of contact blades. Alternatively or additionally, the electrical interface can have a secondary charging coil element for inductive charging. The mechanical interface and the electrical interface can be integrated or formed separately from one another.Furthermore, the battery pack preferably comprises an electronic system. The electronics can have, for example, a printed circuit board, a computing unit, a control unit, a transistor, a capacitor, and / or a memory unit. Additionally or alternatively, it is also conceivable that information is ascertained by the electronics. The electronics are designed for controlling or regulating the battery pack and / or the load. The electronics comprise in particular a BMS (engl. Battery Management System), which is designed to monitor the battery pack. The BMS is designed, in particular, to prevent overcharging and / or deep discharge of the battery pack. The BMS is preferably designed for correct cell balancing. The electronics can also have one or more sensor elements, for example a temperature sensor for determining the temperature within the battery pack or a motion sensor for determining movements. The electronics can alternatively or additionally have a coding element, such as a coding resistor. The electrical contact elements of the electrical interface of the battery pack can be arranged on the printed circuit board of the electronics system or connected to the printed circuit board. In the context of this application, a printed circuit board is to be understood as meaning a circuit carrier which has an organic or inorganic substrate, for example IMS. The printed circuit board can be designed as a rigid printed circuit board or as a flexible printed circuit board. In addition, the printed circuit board can be a populated or an unequipped printed circuit board. The printed circuit board can have a single layer or be formed in multiple layers.The battery cell can be designed as a galvanic cell which has a structure in which one cell pole comes to lie at one end and a further cell pole comes to lie at an opposite end. In particular, the battery cell has a positive cell pole at one end and a negative cell pole at an opposite end. The battery cells are preferably designed as NiMn or NiMn cells, particularly preferably as lithium-based battery cells or Li-ion battery cells. Alternatively, it is also conceivable, for example, for the rechargeable battery cell to be designed as a pouch cell or as a prismatic cell. The battery voltage of the battery pack is generally a multiple of the voltage of an individual battery cell and results from the circuit (parallel or serial) of the battery cells. In the case of conventional battery cells having a voltage of 3.6 V, this results in an example battery voltage of 3.6 V, 7.2 V, 10, 8 V, 14.4 V, 18 V, 36 V, 54 V, 108 V, etc. The battery cell is preferably designed as an at least substantially cylindrical round cell, the cell poles being arranged at ends of the cylindrical shape.Furthermore, it is proposed that the power characteristic has information which comprises available power of the energy supply device with a time component. Advantageously, the control of the electric bicycle can thereby be optimized. The available power of the power supply device preferably also comprises temporal information, for example whether the available power is available now or at a later point in time and / or how long the available power is expected to be available. Alternatively or additionally, it is also conceivable that the performance characteristic comprises a plurality of available powers with different temporal information, for example full power now, drop to 80% of the full power in the next 5 min or 5 km, or the like.It is furthermore proposed that the estimation unit is assigned to the energy supply device. In particular, the estimation unit is assigned to the electronics of the energy supply device. Alternatively, it would likewise be conceivable for the estimation unit to be assigned to the electronics of the electric bicycle.It is also proposed that the energy supply device has at least one temperature sensor, wherein a temperature characteristic variable of the energy supply device can be provided to the estimation unit via the temperature sensor. Advantageously, the determination of the performance characteristic can thereby be optimized. The temperature characteristic variable represents an input variable for the estimation unit, based on which the performance characteristic variable can be determined. The energy supply device can have one or more temperature sensors which are arranged in the interior or on the exterior of the housing of the battery pack.Furthermore, it is proposed that the control unit of the electric bicycle is designed to provide at least one input variable to the estimation unit. The input variable provided by the control unit of the electric bicycle can be designed, for example, as a power request, in particular as a power request at a specific time, to the energy supply device. Advantageously, the control of the electric bicycle can thereby be further optimized.It is furthermore proposed that the control unit is designed to actuate the drive unit at a lower power based on the performance characteristic variable of the estimation unit. Advantageously, the duration of the assistance of the drive unit can be extended by reducing the power of the electric bicycle, so that the driver does not remain completely without assistance power, for example on a hill.It is also proposed that the estimation unit has an adaptation unit which is designed to check a performance characteristic variable determined by the estimation unit, wherein the adaptation unit is designed to adapt the estimation unit if the determined performance characteristic variable deviates from the actually available power in particular by more than a threshold value. Advantageously, the estimation unit can thereby be adapted and improved to the electric bicycle and / or to the driver. The threshold value can be designed, for example, as a threshold value related to the power or a threshold value related to the time. The threshold value is based in particular on a deviation of 10%, preferably 25%, preferably 50%, of the determined performance characteristic variable.Furthermore, it is proposed that the estimation unit has an input characteristic variable in the form of a battery current variable. The battery current variable can be provided by the electric bicycle or the energy supply device.It is furthermore proposed that the adaptation unit has an adaptation parameter in the form of an environmental parameter. The environmental characteristic variable can be configured such that the environmental characteristic variable is dependent on an environmental temperature at the electric bicycle, a travel speed of the electric bicycle, a frame characteristic variable, such as a size of the bicycle frame in which the energy supply device is arranged, and / or a material of the bicycle frame.The invention also relates to a method for controlling an electric bicycle, comprising the following method steps:providing a temperature characteristic variable by a temperature sensor,providing at least one input variable in the form of a power request at a specific time by a control unit of the electric bicycle;determining a performance characteristic of an energy supply device by an estimating unit;controlling the electric bicycle, in particular reducing an assistance power of a drive unit of the electric bicycle, based on the determined power characteristic variable.DRAWINGSFurther advantages are evident from the following description of the drawings. The drawings, specification and claims contain numerous features in combination. The skilled person will expediently also consider the features individually and summarize them to form meaningful further combinations.The following are shown: FIG. 1 shows a perspective view of an electric bicycle with a battery pack according to the invention; FIG. 2 shows a perspective view of a battery pack having an estimation unit; FIG. 3 shows a schematic view of a first embodiment of an estimation unit; FIG. 4 shows a schematic view of a second embodiment of an estimation unit; FIG. 5 is a flowchart showing a control method based on an estimation unit of FIG. 4.DESCRIPTION OF THE EMBODIMENTSFIG. 1 shows a load 10 with an energy supply device 100 in the form of a battery pack 102 in a perspective side view. The load 10 is designed, for example, as an electrically driven means of transportation 12, in particular as an electric bicycle 14. The electric bicycle 14 can be designed, for example, as a pedelec or as an e-bike.The electric bicycle 14 has a frame 18. Two wheels 20 are connected to the frame 18. In addition, the consumer 10 has a drive unit 22, which comprises an electric motor. The electric motor is preferably designed as a permanent magnet-excited brushless direct current motor. The electric motor is designed as a central motor, for example, wherein a hub motor or the like is also conceivable.The drive unit 22 comprises a control unit (not shown) which is designed for controlling or regulating the electric bicycle 14, in particular the electric motor. The electric bicycle 14 has a pedal crank 24. The crank 24 is connected to a crank shaft (not shown).The control unit and the drive unit 22 with the electric motor and the pedal crank shaft are arranged in a drive housing 26 connected to the frame. The drive movement of the electric motor is preferably transmitted to the crankshaft via a transmission (not shown), wherein the amount of assistance by the drive unit 22 is controlled or regulated by means of the control unit.The electric bicycle 14 is electrically and mechanically connected to the battery pack 102 which is designed to supply energy to the drive unit 22. The battery pack 102 is designed, for example, as a replaceable battery pack. The battery pack 102 is, for example, completely accommodated in the frame 18 of the electric bicycle 14 in the connected state. The connection can be effected by axially pushing the battery pack 102 into the down tube of the frame 18 or by pivoting the battery pack 102 laterally into the frame 18. Alternatively, it is also conceivable that the battery pack 102 is designed such that the battery pack 102 can be fastened to an outer side of the frame 18.The energy supply device 100 has a housing 104, in which 20 battery cells (not shown) are arranged by way of example. The housing 104 is formed in multiple parts by way of example and has a tubular main body 110 which is formed from a metal part by way of example. At the end face, the housing 104 has two end plates 108, which are designed as connection plates 112 and each have at least one connecting element 116. The connecting elements 116 are assigned to a mechanical interface of the battery pack 102, which is designed for the mechanical connection of the battery pack 102 to the electric bicycle 14. The connecting elements 116 are formed, for example, as recesses in the connection plate 112, in which recesses a corresponding connecting element, not shown, of the electric bicycle 14 can engage. The tubular base body 110 additionally has, on its side surfaces, in each case, for example, two longitudinal grooves 105, which can likewise be assigned to the mechanical interface, for example, or can be used, for example, for connection to a cover.In addition, the battery pack 102 has a state-of-charge indicator 106. The charge state indicator 106 is connected to an electronic system, not shown, of the battery pack 102, which is arranged in the housing 104 of the battery pack 102. The charge state indicator 106 can be configured to be actuatable by the user via a button press or automatically actuatable, for example by actuating the electronics based on a signal of a motion sensor.Furthermore, the battery pack 102 comprises an electrical interface 114 for electrically connecting the battery pack 102 to the electric bicycle 14. The electrical interface 114 comprises five electrical contact elements, for example, wherein two electrical contact elements are designed as power contacts and at least one electrical contact element is designed for exchanging information between the battery pack 102 and the electric bicycle 14.The electronics of the battery pack 102 have a monitoring system, for example a BMS, for monitoring the battery pack 102, in particular the battery cells. The battery cells are monitored in terms of their voltage by means of a single-cell monitoring system and their temperature by means of a temperature sensor (not shown). In the case of too high a temperature of the battery pack 102, for example in the case of inadequate cooling of the battery pack ( 102) as a result of disadvantageous installation of the battery pack 102 in the electric bicycle 14 or in the case of a long hill climbing with a high power requirement by the driver, this can lead to emergency operation of the battery pack 102 or to disconnection of the battery pack 102, which can likewise have the consequence that the electric bicycle 14 cannot provide any assistance power for the driver by means of the drive unit 22.It is thus advantageous to delay the time at which the driver is no longer assisted by the drive unit 22 as far as possible. For this purpose, the electric bicycle 14, for example the energy supply device 100, has an estimation unit 120 which is designed to ascertain a performance characteristic variable 121, wherein the control unit of the electric bicycle 14 is designed to actuate the drive unit 22 on the basis of the performance characteristic variable.In FIG. 3, a schematic view of a first embodiment of the estimation unit 120 is shown. The estimation unit 120 is assigned to the electronics of the battery pack 102, in particular to the BMS of the battery pack 102. Via the electrical interface 114, input variables for ascertaining the performance characteristic variable 121 can be provided to the estimation unit 120. In addition, the power characteristic 121 can be provided to the electric bicycle 14, in particular to the control unit of the electric bicycle 14, via the electrical interface 114.The input variables are designed in particular as information, parameters, setting, etc., on the basis of which the estimation unit 120 ascertains the power variable 121.A first input variable is designed as a temperature characteristic variable 122 of the energy supply device 100. The temperature characteristic variable is detected by a temperature sensor of the energy supply device 100. It is likewise conceivable for the estimation unit 120 to have a plurality of first input variables in the form of temperature characteristic variables 122. The temperature characteristic variable can be designed, for example, as a temperature value or as a temperature gradient.A second input variable is designed as a power request 124. The power request 124 is provided by the electric bicycle 14, in particular by the control unit of the electric bicycle 14. The power request 124 can be determined by the control unit, for example, based on sensor data and / or navigation data. The sensor data are preferably provided by the sensor system of the electric bicycle 14, wherein the navigation data are preferably provided by an external unit, for example a smartphone, and / or a computing network, for example a cloud. The power request 124 can be designed, for example, as a request to provide only a predefined power characteristic 121. However, the power request 124 can also be designed in such a way that a required power, for example a maximum power of the system, is requested. Alternatively or additionally, a duration can also be requested as to how long the requested and / or maximum power can still be expected to be provided by the energy supply device 100. Alternatively or additionally, it is likewise possible to provide that the power request 124 comprises information about the time at which power is required or requested.The provision of the power request 124 can take place continuously, for example at regular and / or predefined time intervals. Alternatively, the time of the power request 124 can also be determined first by the control unit of the electric bicycle, for example based on sensor data, in particular sensor data in the form of an inertial sensor system. By way of example, it can be determined by the control unit on the basis of the sensor data of the inertial sensor system that the electric bicycle 14 is on a hill climbing surface and that a high assistance power is currently required for the driver. Based on navigation data, in particular based on route information, a power request 124 can likewise be determined, since, for example, essentially no power is required on a departure and a higher power is required on a steep slope in a driver-specific manner.On the basis of the first input variable and the second input variable, the power characteristic variable 121 is ascertained by the estimating unit 120, which is in turn provided to the control unit of the electric bicycle 14 by means of the electrical interface 114. The power characteristic 121 is determined in particular by a predefined algorithm. Alternatively, it would also be conceivable for the estimating unit 120 to have an algorithm which was determined on the basis of a machine learning system or is continuously trained. For optimization, the performance parameter 121 can additionally also be provided to an external device or a computing network. For this purpose, the electric bicycle 14 and / or the energy supply device can have a communication interface, preferably a wireless communication interface, such as Bluetooth or LTE.The control unit of the electric bicycle 14 controls the drive unit 22 of the electric bicycle 14 based on the performance characteristic 121 of the estimation unit 120.In Fig. 4 an alternative embodiment of the estimating unit 120a is shown. The estimation unit 120 adiffers here from the previously described estimation unit 120 in particular in that the estimation unit 120 acomprises an adjustment unit 125 awhich is configured to check a performance characteristic variable 121 adetermined by the estimation unit 120 a, wherein the adjustment unit 125 ais configured to adjust the estimation unit 120 a, in particular the algorithm of the estimation unit 120 a, if the determined performance characteristic variable 121 adiffers from an actually available performance, in particular deviates by more than a threshold value.The adaptation unit 125 ain this case has adaptation parameters in the form of an environmental parameter, in particular. The environmental parameter can be configured depending on the environmental temperature of the battery pack 102, the cooling of the battery pack 102, the geometry of the frame 20 of the electric bicycle 14, etc. In addition, the estimation unit 120 aincludes a third input variable in the form of a battery current characteristic variable 128 a.In FIG. 5, an exemplary flow chart for a method for controlling the electric bicycle 14 and adapting the estimating unit 120 ais shown.In a first step 200, a first input variable in the form of a temperature characteristic variable 122 is provided by the battery pack 102 to the estimation unit 120 a.In a second step 202, a second input variable in the form of a power request 124 is provided to the estimation unit 120 abased on navigation data by the electric bicycle 14. By way of example, the power request comprises a request as to how long a maximum power of the energy supply device 100 can be called up.In a third step 204, a third input variable in the form of a battery current characteristic variable 128 ais provided by the battery pack 102 to the estimation unit 120 a.In a fourth step 206, the power characteristic 121 is ascertained. The performance characteristic 121 is designed, for example, in such a way that the maximum performance can be called up for 10 minutes.In a fifth step 208, the performance characteristic 121 is provided to the control unit of the electric bicycle 14.In a sixth step 210, the control unit of the electric bicycle 14 drives the drive unit 22 with maximum power for 10 minutes. Alternatively, the control unit would drive the drive unit 22 with reduced power in a step 211 should the maximum power need for a longer time.In a seventh step 212, the ascertained performance characteristic 121 is checked by the adaptation unit 125 a. By way of example, the check takes place in a time-defined cycle, in particular a minute cycle. If the power of the battery pack 102 that can be provided matches the ascertained power characteristic 121, then no adaptation of the estimation unit 120 atakes place. If there is a deviation of the power that can actually be provided by more than a threshold value, for example 20%, then in a step 214 the environmental characteristic variable is adjusted by the adjusting unit 125 ato optimize the ascertainment of the performance characteristic variable. This would therefore be the case, for example, if the maximum power were no longer available after 7 minutes, since the battery pack 102 is overheated. Alternatively, it would also be conceivable to perform the adaptation first if the threshold value is exceeded several times. The adapted estimation unit 120 adetermines a different performance characteristic based on the same input variables.

Claims

Electric bicycle with a drive unit (22), with an energy supply device (100) for supplying energy to the drive unit (22) and with a control unit which is designed to control the drive unit (22), characterized in that the electric bicycle (14), in particular the control unit or the energy supply device (100), has an estimation unit (120) which is designed to ascertain a performance characteristic variable (121), and the control unit is designed to actuate the drive unit (22) on the basis of the performance characteristic variable (121).Electric bicycle according to claim 1, characterized in that the performance characteristic (121) comprises information comprising an available power of the energy supply device (100) with a time component.Electric bicycle according to one of the preceding claims, characterized in that the estimation unit (120) is assigned to the energy supply device (100).Electric bicycle according to one of the preceding claims, characterized in that the energy supply device (100) has at least one temperature sensor, wherein a temperature characteristic variable (122) of the energy supply device (100) can be provided via the temperature sensor of the estimation unit (120).Electric bicycle according to one of the preceding claims, characterized in that the control unit of the electric bicycle (100) is designed to provide at least one input variable to the estimation unit (120).Electric bicycle according to Claim 5, characterized in that the input variable of the control unit is designed as a power request (124), in particular as a power request at a specific time, to the energy supply device (100).Electric bicycle according to one of the preceding claims, characterized in that the control unit is designed to actuate the drive unit (22) at a lower power based on the performance characteristic variable (121) of the estimation unit (120).Electric bicycle according to one of the preceding claims, characterized in that the estimation unit (120a) has an adjustment unit (125a) which is designed to check a performance characteristic variable (121a) determined by the estimation unit (120a), wherein the adjustment unit (125a) is designed to adjust the estimation unit (120a) if the determined performance characteristic variable (121a) deviates from the actually available performance in particular by more than a threshold value.Electric bicycle according to Claim 8, characterized in that the estimating unit (120a) has an input characteristic in the form of a battery current characteristic (128a).Electric bicycle according to either of Claims 8 and 9, characterized in that the adaptation unit (125a) has an adaptation parameter in the form of an environmental parameter.Method for controlling an electric bicycle (14), comprising the following method steps: - providing a temperature characteristic variable (122) by a temperature sensor, - providing at least one input variable in the form of a power request (124) at a specific time by a control unit of the electric bicycle (14); - determining a power characteristic variable (121) of an energy supply device (100) by an estimating unit (120); - controlling the electric bicycle (14), in particular reducing an assistance power of a drive unit (22) of the electric bicycle (14), based on the determined power characteristic variable (121).

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