DE102022124443A1 - Method for electrically charging an energy storage device of a motor vehicle, control device and motor vehicle - Google Patents

Abstract

The invention relates to a method for electrically charging an energy storage device (13) of a motor vehicle (12) on a charging device (32) external to the vehicle, which draws a charging current for charging the energy storage device (13) at least partially from a regenerative energy source (38). A generation output (E) of the regenerative energy source (38) is determined as a function of at least one situation parameter (S; S1, S2, S3, S4) determined by means of at least one motor vehicle sensor (14, 16, 18, 20), which is an environmental characteristic Environment of the regenerative energy source (38) and / or a weather at the location of the regenerative energy source (38), and a charging power (L), with which the charging of the energy storage (13) is carried out, during charging depending on the determined generation power (E) regulated.

Description

The invention relates to a method for electrically charging an energy storage device of a motor vehicle on a charging device external to the vehicle, which draws a charging current for charging the energy storage device at least partially from a regenerative energy source. Furthermore, the invention also relates to a control device and a motor vehicle.

Renewable energy sources can be, for example, a PV (photovoltaic) system installed in or on a house and the vehicle-external charging device can be, for example, a wallbox that is integrated into a power network, for example a household power network, which is partly is fed via the PV system mentioned, and, for example, is also partly fed via a public power grid, for example if the energy generated by the PV system is not sufficient. More and more households have their own renewable energy source, such as a PV system. It would therefore be advantageous to optimally integrate electricity generation using such a PV system into the charging strategy for charging an energy storage device in a motor vehicle, for example on a wallbox connected to the household network. Wallboxes usually only provide a fixed charging power with which the motor vehicle is charged. As a result, it can happen that, for example, more electricity is required to charge the vehicle than the PV system is making available at that moment and although a lower charging power might also be sufficient to achieve the desired state of charge of the battery or the energy storage of the motor vehicle to be achieved at a specified time. The energy that is currently not available from the PV system and is additionally required for charging is then obtained from the public power grid, which is usually significantly more expensive for the user. However, the problem when adapting the charging strategy to electricity generation by a PV system is that there is usually no means of communication with the PV system from the vehicle or from the charging device to the PV system in order to find out how much electricity is currently being generated the PV system can be made available, or this can only be achieved with very complex means.

Furthermore, it is also known from the prior art that a weather forecast, in particular from the Internet, can be retrieved in order to determine the electrical energy available from solar cells, for example in DE 10 2018 201 045 A1 and the DE 10 2016 217 162 A1 described.

However, such weather forecasts are known to contain a certain and sometimes very high degree of inaccuracy.

The object of the present invention is therefore to provide a method, a control device and a motor vehicle which make it possible to optimize utilization of the energy provided by a renewable energy source when charging an energy storage unit of the motor vehicle.

This task is solved by a method, a control device and a motor vehicle with the features according to the respective independent patent claims. Advantageous embodiments of the invention are the subject of the dependent claims, the description and the figure.

In a method according to the invention for electrically charging an energy storage device of a motor vehicle on a charging device external to the vehicle, which draws a charging current for charging the energy storage device at least partially from a regenerative energy source, a generation output of the regenerative energy source is determined as a function of at least one situation parameter determined by at least one motor vehicle sensor, which relates to an environmental characteristic of an environment of the renewable energy source and / or a weather at the location of the renewable energy source. Furthermore, a charging power with which the energy storage is charged is regulated during charging depending on the determined generation power.

The invention is based on the knowledge that a motor vehicle typically already has sensors that make it possible to determine environmental properties or weather conditions that influence the current generation output of a renewable energy source. For example, a rain sensor in the motor vehicle or a brightness sensor can be used to determine whether the sun is currently shining or it is cloudy. In addition, such a motor vehicle is typically in close proximity to the renewable energy source at the time of charging, for example if it and the charging device are assigned to a common household. This means that the current weather conditions or other environmental characteristics, such as the time of year or the position of the sun, which influence energy production using the renewable energy source, can be determined extremely precisely at the location of the renewable energy source using motor vehicle sensors. Furthermore, this information does not necessarily have to be used as an alternative to weather data obtained from the Internet or similar, but can also be used additionally to determine weather conditions or environmental characteristics even more precisely. The accuracy in estimating or determining the generation output of the renewable energy source can thus be significantly increased, and accordingly this allows an optimization of the adaptation of the charging strategy to the determined generation output, in particular by selecting or regulating the charging power for charging the energy storage depending on the determined generation output . If, for example, it is determined that the generation output is very high, charging can be carried out with a higher power than in the case where it is determined that the generation output of the renewable energy source is currently very low. This allows optimal utilization of the energy provided by a renewable energy source and minimizes additional costs for a user.

The motor vehicle can be an electric vehicle or a hybrid vehicle with an external charging option for charging the energy storage device. The energy storage device can be designed, for example, as a high-voltage battery of the motor vehicle or also a medium-voltage battery. The charging device external to the vehicle is preferably a wall box, in particular in a private household. In principle, however, it can also be a public charging device, for example a public charging station, which can also have its own renewable energy source, for example in the form of a photovoltaic system. The charging device is also preferably designed in such a way that the charging current for charging the energy storage device can not only be obtained from the renewable energy source, but, for example if the current generated by the renewable energy source is not sufficient for charging, can additionally or alternatively be obtained from a power grid. Furthermore, the term “power supply from a renewable energy source” should be understood to mean both a direct power supply, according to which the power generated by the renewable energy source is used directly to charge the energy storage device without intermediate storage in another energy storage device, for example in the household, and a power supply from an intermediate storage device, for example in the household, for intermediate storage of the power generated by the renewable energy source. A renewable energy source is preferably understood to mean a photovoltaic system, in particular in a private household, but it can generally also be another renewable energy source, for example a wind turbine, in particular a private wind turbine. The charging current provided by the renewable energy source is therefore not a charging current provided via a public power grid. The renewable energy source should therefore represent a renewable energy source locally assigned to the charging device. In other words, the charging device and the renewable energy source are arranged in a predetermined proximity to one another, for example at a maximum distance of a few tens or a few hundred meters. Preferably, they are assigned to the same facility, in particular the same house or household.

In an advantageous embodiment of the invention, the at least one situation parameter is detected by a motor vehicle sensor of the motor vehicle and/or by a motor vehicle sensor of a second motor vehicle. So not only the motor vehicle sensors of the motor vehicle that is currently being charged at the charging device can be used to determine environmental properties and weather conditions for determining the generation output, but also motor vehicle sensors of other motor vehicles, which are then preferably in the vicinity of the one currently being charged motor vehicle. Under certain circumstances, it may be the case that no reliable or meaningful environmental data or weather data can currently be provided using the motor vehicle sensors of the charging motor vehicle, for example because it is currently parked in a garage for charging. On the other hand, another motor vehicle that is, for example, driving past the house or parked in the open air in the driveway of the same house may be able to record significantly more precise weather data and environmental characteristics. These can then be transmitted, for example, directly to the charging motor vehicle, or to a backend server, which forwards this data to the motor vehicle or itself determines the generation output. A backend server is an Internet server. The transmission of the recorded data, for example between the second motor vehicle and the charging motor vehicle, which can also be referred to as the first motor vehicle, or a backend server can be done, for example, by radio, for example via the Internet, or also via Car2X communication or Car2Car communication take place. This allows even more precise determination of current environmental properties and weather conditions.

In a further advantageous embodiment of the invention, the generation power is determined as the current generation power and the environmental characteristic represents a current environmental characteristic and/or the weather represents current weather. In other words, it is preferred to present current environmental characteristics and/or current weather to determine data and based on this to determine a current generation output of the renewable energy source, depending on which a current charging output is then regulated accordingly. This allows very precise adjustment to current weather conditions and the current generation output of a photovoltaic system, for example. However, it would also be conceivable to forecast the generation output for a future point in time, in particular depending on predicted future environmental properties or weather data. However, the current generation output can be determined much more precisely and the charging output can also be regulated very flexibly and quickly to other values, so that a forecast for future points in time is unnecessary.

In a further advantageous embodiment of the invention, the at least one situation parameter is detected by means of the motor vehicle sensor, which represents at least one of the following: a rain sensor, a brightness sensor, in particular for detecting an ambient brightness of the motor vehicle, a temperature sensor, in particular for detecting an ambient temperature of the motor vehicle, a Sun position sensor, an ultrasonic sensor, an outdoor camera, a lidar, a radar and a GPS receiver. The ultrasonic sensor as well as the lidar and radar are, in particular, surroundings sensors of the motor vehicle that are aimed at the surroundings of the motor vehicle. Overall, numerous different sensors of a motor vehicle can be used, depending on the equipment of the motor vehicle, to determine current environmental properties and weather conditions. From these, the current generation output of the renewable energy source can be determined very precisely. The GPS data that can be provided using the GPS receiver can, for example, calculate the current position of the sun, for example depending on the current season or the current date and time. The GPS data can also be used to obtain and use online weather data for the current location.

Therefore, it represents a further advantageous embodiment of the invention if the at least one situation parameter or at least one second situation parameter on the basis of which the generation power is determined is determined on the basis of online data, in particular online weather data, which is retrieved in particular from the motor vehicle. In other words, online data, in particular online weather data, can optionally also be used to determine the situation parameter or to determine a further second situation parameter. For example, it can also be provided to use online data whenever it is not possible to reliably determine the situation parameter using the at least one motor vehicle sensor. This can be the case, for example, if the motor vehicle is parked in a garage and therefore cannot determine environmental properties or weather conditions outside the garage or cannot do so reliably. However, this online weather data can not only be retrieved from the motor vehicle, but also, for example, from the above-mentioned backend server. In particular, it can be provided that the method described can be carried out by a control device that can be part of the motor vehicle, but can also be part of a backend server. The described method can also be executed partly by a motor vehicle control device and partly by a control device of a backend server.

However, not only online weather data can be used as online data. For example, additional useful data can also be accessed via the Internet, which enables an even more precise determination of the generation output, as will be explained in more detail later in connection with the calibration option. To give a few examples in advance, it can also be provided, for example, that an actual maximum usable generation output or residual output is determined from the generation output by also taking the household's own consumption into account. For example, location-specific household consumption curves can also be retrieved from the Internet and used to determine the usable remaining power. Swarm data from other households or motor vehicles collected in the backend server can also be accessed and used to enable the generation output or usable remaining power to be determined in an even more precise manner.

In a further advantageous embodiment of the invention, the situation parameter represents at least one of the following: a degree of cloudiness, a position of the sun, an outside temperature, an ambient brightness, a wind strength, a current location of the motor vehicle, a time of day, a season and / or a date. Depending on the design of the renewable energy source, knowledge of these situation parameters is very advantageous in order to be able to estimate the current generation output as accurately as possible. While knowledge of the wind strength is particularly useful for determining the generation output of a wind turbine, the other parameters mentioned are particularly useful for determining the current generation output of a photovoltaic system.

In a further advantageous embodiment of the invention, the generation output and/or a usable residual power determined depending on the generation output is determined as a function of at least one calibration parameter, which represents at least one of the following: a maximum generation output that can be provided by the renewable energy source, a household's own consumption, which is at least partially supplied with electricity generated by the renewable energy source, a parking location of the motor vehicle, which in particular indicates whether the motor vehicle is in a garage or a carport or in the open air, and feedback information relating to an unused amount of energy an energy generated by the renewable energy source or an additional amount of energy obtained from a public power grid in a predeterminable past period.

When determining the generation output, in particular the current generation output, the system parameters of the system providing the renewable energy source, for example the photovoltaic system, are very useful. Above all, knowing the maximum generation output that can be provided by this system is very helpful. This can, for example, be specified once by a user. If such information is missing or if such information is not provided by the user, a predefined standard value or average value can be used, for example. Taking into account a household's own consumption is also very advantageous. This can be used in particular to determine an actually usable remaining power. The usable remaining power can, for example, result from the difference between the current generation output and the self-consumption. The self-consumption of such a household can also be entered manually by a user, for example as an average value or as a consumption curve, which relates, for example, to a predeterminable period of time, e.g. a day, a week, a month or a year. It is also conceivable to retrieve such location-specific average household consumption curves for the current location of the motor vehicle from the Internet and make them available to the control device that carries out the method.

This means that the power required for another use, for example from other consumers in the power network of the photovoltaic system, such as a heat pump or other household electricity consumers, can also be advantageously taken into account when determining the usable remaining power. The user input, for example for the calibration parameter or user input explained in more detail below, can generally be made, for example, via an input mask in the vehicle or via an app, that is, an application program, on the user's mobile communication device or on the user's computer device. The user or vehicle owner can use this to specify the maximum output of their PV system, for example 5 kilowatts per hour.

A parking location of the motor vehicle can also be taken into account as a calibration parameter. The parking location typically corresponds to the location of the charging device when the motor vehicle is currently being charged. The storage location can also be specified accordingly through user input. The user can, for example, enter whether the charging device and the corresponding parking location of the motor vehicle is in a garage, in a carport or in the open air during charging. Accordingly, it may be that the environmental data and weather data provided by the motor vehicle sensors are only taken into account in part or in a modified manner. Ambient temperature, time of day or time can also be taken into account, for example, if the motor vehicle is parked in a garage. The brightness values recorded by the vehicle, on the other hand, are then less relevant. These can still be used in a carport, whereby, for example, it can be taken into account mathematically that the actual brightness value is probably higher than that currently recorded by the vehicle in the carport. Depending on the parking location, for example, more or less situational parameters detected by motor vehicle sensors can be included in the determination of the generation output and/or the situational parameters can be included with a corresponding higher or lower weighting depending on the parking location of the motor vehicle. The system can therefore advantageously be calibrated to the specific situation on site, for example by the user entering the general output of the photovoltaic system, the amount of electricity currently generated under various conditions into an input mask in the vehicle or an app, for example sun, clouds, Morning, midday, afternoon, spring, summer, autumn, winter, parking location in the garage or outdoors or in the sun or in a shaded area, and the vehicle or the control device does this with the currently available sensor data and the optional online weather data, for example For example, via Connect services, this enables a simulation of the amount of electricity generated by the renewable energy source in order to regulate the optimal charging power within the vehicle, for example in terms of the maximum self-consumption of the photovoltaic system.

Furthermore, it is also very advantageous to use feedback information for calibration. Such feedback information may relate to a past period and indicate whether energy generated by the renewable energy source within this period remained unused or whether additional electricity had to be purchased from a public power grid. This information can subsequently be used to adjust the charging power control accordingly for a current period of time and, for example, to set the charging power slightly higher or lower accordingly. Such feedback information can also be obtained, for example, via user input or, for example, via swarm data that is provided or collected by the backend.

In a further advantageous embodiment of the invention, the charging power is additionally regulated depending on a user specification, which specifies a final charge state of the energy storage to be achieved by charging, and/or a maximum duration of the charging process and/or a minimum and/or maximum charging power and/or a priority indication, which in particular specifies whether optimal use of the energy generated by the renewable energy source or reaching a specific final state of charge of the energy storage within a specific time is priority. A user can therefore advantageously provide additional information that can be taken into account when charging and depending on which the charging power can also be regulated. The user can therefore make appropriate specifications regarding general conditions. For example, this can specify the minimum or maximum charging power that should be used for charging. It can also specify which final charge state of the energy storage device should at least be reached, in particular by which point in time or within which maximum charging time period. For example, the user can also specify the time of the next trip. Such a user specification can, for example, be given higher priority than the optimal utilization of the power generated by the renewable energy source. Thus, for example, the charging power can be adjusted to the current generation power of the renewable energy source, as long as it is ensured that the minimum final charging state desired by the user is safely achieved by the time desired by the user. This increases user comfort. In addition, it can be avoided that the motor vehicle cannot be charged or cannot be charged sufficiently due to unfavorable weather conditions.

Furthermore, the invention also relates to a control device for controlling a charging process for electrically charging an energy storage device of a motor vehicle on a vehicle-external charging device, which is designed to obtain a charging current for charging the energy storage device at least partially from a regenerative energy source. The control device is designed to determine a generation output of the regenerative energy source as a function of a situation parameter determined by means of at least one motor vehicle sensor, which relates to an environmental characteristic of an environment of the regenerative energy source and / or a weather at the location of the regenerative energy source, and a charging power which charging of the energy storage is carried out is to be regulated during charging depending on the determined generation power.

The advantages described for the method according to the invention and its embodiments apply equally to the control device according to the invention.

Furthermore, the invention also relates to a motor vehicle with a control device according to the invention or one of its embodiments. A backend server with a control device according to the invention or one of its configurations should also be considered to be part of the invention.

The control device can have a data processing device or a processor device that is set up to carry out an embodiment of the method according to the invention. The processor device can have at least one microprocessor and/or at least one microcontroller and/or at least one FPGA (Field Programmable Gate Array) and/or at least one DSP (Digital Signal Processor). Furthermore, the processor device can have program code that is set up to carry out the embodiment of the method according to the invention when executed by the processor device. The program code can be stored in a data memory of the processor device. A processor circuit of the processor device can, for example, have at least one circuit board and/or at least one SoC (System on Chip).

The invention also includes further developments of the control device according to the invention, which have features as have already been described in connection with the further developments of the method according to the invention. For this reason, the corresponding developments of the control device according to the invention are not described again here.

The motor vehicle according to the invention is preferably designed as a motor vehicle, in particular as a passenger car or truck, or as a passenger bus or motorcycle.

The invention also includes the combinations of the features of the described embodiments. The invention therefore also includes implementations that each have a combination of the features of several of the described embodiments, provided that the embodiments have not been described as mutually exclusive.

Examples of embodiments of the invention are described below. The exemplary embodiments explained below are preferred embodiments of the invention. In the exemplary embodiments, the described components of the embodiments each represent individual features of the invention that are to be considered independently of one another and which also further develop the invention independently of one another. Therefore, the disclosure is intended to include combinations of the features of the embodiments other than those shown. Furthermore, the described embodiments can also be supplemented by further features of the invention that have already been described.

For this purpose, the only figure shows a schematic representation of a charging system arrangement 10 according to an exemplary embodiment of the invention. The charging system arrangement 10 is designed to carry out a method for electrically charging an energy storage device 13 of a motor vehicle 12 as part of the charging system arrangement 10 according to an exemplary embodiment of the invention. In this example, the motor vehicle 12 has several motor vehicle sensors, such as a temperature sensor 14, a sun position sensor 16, a brightness sensor 18, a GPS module 20. Additionally or alternatively, the motor vehicle 12 can also have other sensors for recording environmental or weather data . Furthermore, the motor vehicle 12 also has a communication module 22 for communication with an external server 24, for example an Internet server 24. Furthermore, the motor vehicle 12 has a control device 26 and a user interface 28 via which the user can make entries.

Furthermore, the motor vehicle 12 includes a charging system 30 for charging the energy storage 13 of the motor vehicle 12. The energy storage 13 can be a high-voltage battery 13, for example. The charging system 30 can be coupled, for example via a charging cable, to a charging device 32 external to the vehicle, which in this example is designed as a wallbox 32. This is connected to a power grid 34, in particular a household power grid 34, which in turn can be fed from a public power grid 36 on the one hand and, on the other hand, from a renewable energy source assigned to the household 40, in this example a PV system 38. In order to enable economically optimal use of the electricity generated by the PV system 38 to charge the motor vehicle 12, it is provided that the control device 26 detects at least one situation parameter S, which is provided by the motor vehicle sensors 14, 16, 18, 20 . In this example, the temperature sensor 14 provides, for example, a temperature, in particular a current ambient temperature of the motor vehicle 12, as the first situation parameter S1, the sun position sensor 16 provides the current position of the sun as the second situation parameter S2, and the brightness sensor 18 provides a current ambient brightness of the motor vehicle as the third situation parameter S3 12 and the GPS module 20 a current position of the motor vehicle 12 as a fourth situation parameter S4. Furthermore, in this example, a fifth situation parameter S5 can be obtained from the Internet server 24 via the communication module 22, for example in the form of online weather data. These situation parameters S can now be used to estimate a current generation output E of the photovoltaic system 38. This further makes it possible to regulate the power L with which the energy storage 13 is currently charged, depending on the determined current generation power E. Depending on the determined generation power E, the control device 26 can specify the current power value L to be set or regulated in accordance with the charging system 30 of the vehicle 12. This then requests a corresponding charging power from the charging device 32.

By using the available sensor data, it is advantageously possible to provide a simulation of the amount of electricity currently generated by the PV system 38 and to regulate the charging power L depending on this. This allows the amount of electricity generated by the PV system 38 to be optimally utilized. An additional grid purchase from the public power grid 36 as well as a feed into the public power grid 36 of electricity generated by the PV system 38 can thus be reduced to a minimum, which maximizes the economic efficiency of the charging process for the user.

In order to further refine and specify this procedure, additional parameters can also be taken into account. In particular, a household-specific or system-specific calibration can also be carried out. This is made possible by the control device 26 also takes into account one or more calibration parameters K to determine the generation power and in particular an actually usable residual power R. For example, the household's own consumption V 40 can also be taken into account, for example in the form of a location-specific household consumption curve provided by the Internet server 24. This internal consumption V can be subtracted from the current generation output E, resulting in the usable remaining power R. The charging power L to be adjusted can then be determined depending on this residual power R. Furthermore, one or more system parameters AP of the photovoltaic system 38 can also be received and taken into account by the control device 26 via the user interface 28 in order to determine the generation power E and/or the residual power R. Such a system parameter primarily represents the maximum generation output that can be output by the PV system 38, for example 5 kilowatts per hour. This system parameter AP can be entered once by a user via the user interface 28 and can be used again each time a charging process is carried out. The control device 26 can generally store the calibration parameters K accordingly. These then do not have to be obtained again every time. In this example, the user interface 28 is also part of the vehicle 12 itself and can be provided, for example, by an input mask in the vehicle 12. However, it is also conceivable to provide the user interface 28 as a user interface external to the vehicle, for example via a mobile communication device and an app running on it. The data specified there can then be transmitted to the motor vehicle 12 in a corresponding manner, for example via the communication module 22.

In addition, when determining the charging power L, other user specifications B that can be specified by the user can also be defined and taken into account as boundary conditions. For example, as such a user specification B, the user can specify the desired state of charge or final state of charge of the battery 13 at a specified time, the power desired for vehicle charging, in particular a minimum or maximum power or also a desired charging speed, for example in the form "as quickly as possible" , “medium”, “slow”, or it can be specified whether a maximum power supply from the PV system 38 is desired or whether the fill level of the battery 13 is priority.

Although not shown here, in further advantageous embodiments the use of sensor data from nearby vehicles can also be provided in order to enable even more precise simulation. In addition, continuous optimization of the calculations may be possible, for example through artificial intelligence, which can be implemented by the control device 26. For this purpose, the control device 26 can also receive or request user feedback from time to time, via which the control device 26 can be provided with feedback or information about whether the charging strategy or estimate of the generation power E provided by the control device 26 tends to be too high or is too low. For example, the user can use the interface 28 to indicate whether a lot of additional energy had to be obtained from the public power grid 36 in a given past period or whether there was a lot of renewable energy left that had to be fed into the power grid 36. Accordingly, the control device 26 can adapt the charging strategy, that is, the control strategy for regulating the charging power L, based on this feedback.

Overall, the examples show how the invention can be used to create a system for automatically regulating the charging power in a motor vehicle, in particular a purely battery-electric vehicle (BEV) or a plug-in hybrid electric vehicle (PHEV) by using the sensor data and online Weather data and a calibration option can be provided. The charging power control system can use the data from the temperature sensor, the brightness sensor, the sun position sensor, the GPS receiver and the online weather data to regulate the charging power of the motor vehicle when the motor vehicle is connected to a wallbox that is integrated into a power grid, which has electricity generation using a PV system. This enables economically optimal use of the electricity generated by the PV system to charge the motor vehicle.

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102018201045 A1 [0003]
• DE 102016217162 A1 [0003]

Claims (10)

Method for electrically charging an energy storage device (13) of a motor vehicle (12) at a vehicle-external charging device (32), which draws a charging current for charging the energy storage device (13) at least partially from a regenerative energy source (38), characterized in that - a generation power (E) of the regenerative energy source (38) is determined as a function of at least one situation parameter (S; S1, S2, S3, S4) determined by means of at least one motor vehicle sensor (14, 16, 18, 20), which relates to an environmental property of an environment of the regenerative energy source (38) and/or a weather at the location of the regenerative energy source (38), - wherein a charging power (L) with which the charging of the energy storage device (13) is carried out is regulated during charging as a function of the determined generation power (E). Procedure according to Claim 1 , characterized in that the at least one situation parameter (S; S1, S2, S3, S4) is detected by a motor vehicle sensor (14, 16, 18, 20) of the motor vehicle (12) and / or by a motor vehicle sensor of a second motor vehicle. Method according to one of the preceding claims, characterized in that the generation output (E) is determined as a current generation output (E) and the environmental characteristic represents a current environmental characteristic and/or the weather represents a current weather. Method according to one of the preceding claims, characterized in that the at least one situation parameter (S; S1, S2, S3, S4) is detected by means of the motor vehicle sensor (14, 16, 18, 20), which represents at least one of the following: - one Rain sensor, - a brightness sensor (18), - a temperature sensor (14), - a sun position sensor (16), - an ultrasonic sensor, - an outdoor camera, - a lidar, - a radar, - a GPS receiver (20). Method according to one of the preceding claims, characterized in that the at least one situation parameter (S; S1, S2, S3, S4) or at least one second situation parameter (S; S5), depending on which the generation power (E) is determined, in Dependence on online data, in particular online weather data, is determined, which is retrieved in particular by the motor vehicle (12). Method according to one of the preceding claims, characterized in that the situation parameter (S; S1, S2, S3, S4) represents at least one of the following: - a degree of cloudiness; - a position of the sun (S2); - a temperature (S1); - a brightness (S3); - a wind force; - a current location (S4) of the motor vehicle (12); - a time of day; - a season and/or a date. Method according to one of the preceding claims, characterized in that the generation power (E) and/or a usable residual power (R) determined as a function of the generation power (E) is determined as a function of at least one calibration parameter (K; AP, V) which represents at least one of the following: - a maximum generation power (AP) that can be provided by the regenerative energy source (38); - a self-consumption (V) of a household (40) that is at least partially supplied with electricity generated by the regenerative energy source (38); - a parking location of the motor vehicle (12), which in particular indicates whether the motor vehicle (12) is in a garage or a carport or in the open air; - feedback information relating to an unused amount of energy generated by the regenerative energy source (38) or an additional amount of energy obtained from a public power grid (36) in a predeterminable past period. Method according to one of the preceding claims, characterized in that the charging power (L) is additionally regulated depending on a user specification (B), which - specifies a final charge state of the energy storage (13) to be achieved by charging; and/or - specifies a maximum duration of the charging process; and/or - specifies a minimum and/or maximum charging power; and/or - a priority indication, which in particular specifies whether optimal use of the energy generated by the regenerative energy source (38) or reaching a specific final state of charge within a specific time is priority. Control device (26) for controlling a charging process for electrically charging an energy storage device (13) of a motor vehicle (12) on a vehicle-external charging device (32), which is designed to obtain a charging current for charging the energy storage (13) at least partially from a regenerative energy source (38), characterized in that the control device (26) is designed to - a generation power (E ) of the regenerative energy source (38) depending on a situation parameter (S; S1, S2, S3, S4) determined by means of at least one motor vehicle sensor (14, 16, 18, 20), which is an environmental characteristic of an environment of the regenerative energy source (38 ) and/or weather at the location of the renewable energy source (38); and - to regulate a charging power (L), with which the energy storage (13) is charged, during charging depending on the determined generation power (E). Motor vehicle (12) with a control device (26). Claim 9 .

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