Method for operating a motor vehicle during the charging process of a power battery, and motor vehicle

Abstract

The present invention relates to a method for operating a motor vehicle (1) for a charging process of a power battery (3) of the motor vehicle (1), wherein the power battery (3) is connected to a charging facility (14) outside the motor vehicle via a charging device (4) of the motor vehicle (1), wherein in a control device (6) assigned to the charging device (4) and constructed inside the motor vehicle (1): user information describing at least one user expectation with respect to the charging process is received; energy information related to the electrical energy provided by the charging facility (14) is received from the charging facility (14) via a communication connection with the charging facility (14); a charging time period that is expected to be available for the charging process is determined; time-resolved optimization information of the energy information related to the optimization target is used to determine a charging plan for the charging time period that is optimized with respect to at least one optimization target determined from the user information; and the charging process is carried out according to the charging plan.

Description

Technical Field

[0001] The present invention relates to a method for operating a motor vehicle while its power battery is being charged, wherein the power battery is connected to a charging facility external to the motor vehicle via a charging device of the motor vehicle. Background Art

[0002] Modern motor vehicles, such as electric vehicles and / or hybrid vehicles, in particular plug-in hybrid vehicles, have an electric traction battery whose stored electrical energy can be used to drive the vehicle. This traction battery can also be called a high-voltage battery. In order to be able to charge the high-voltage battery via external charging facilities, such as charging stations, wall boxes, etc., the motor vehicle usually has a charging device assigned to the traction battery, which is also called an on-board charger (OBC). The motor vehicle is connected to the charging facility via a corresponding connecting cable and the charging process can be carried out under the control of the control device assigned to the charging device. In this case, the charging process usually starts immediately when connecting to the charging device, in particular after the charging parameters have been determined. The charging process is limited by the acceptance capacity of the traction battery or the motor vehicle.

[0003] It has already been proposed to provide the possibility of influencing the actual execution of the charging process. For example, it is known to specify the departure time as the end-of-charging information so that the time window for charging the traction battery can be postponed if necessary. The charging current / charging power is limited only according to the specified acceptance capacity of the traction battery or the characteristics of the charging facility.

[0004] US 2015 / 0298567 A1 relates to a system and method for reducing power consumption in electric vehicles connected to a charging station. Communication between the electric vehicles and a tracking server is performed via a wireless network. The tracking server collects user information and location information for charging electric vehicles. If consumption reduction information is received from the tracking server, a charging interruption signal can be sent to the identified electric vehicles.

[0005] US 2013 / 0179061 A1 relates to an expert system for managing an electrical grid, wherein charging stations are connected to the grid. Electric vehicles can be connected to the charging stations, whereby the power generated by the connected electric vehicles can be fed back into the grid. In a more conventional application, the expert system can manage the charging process for the entire grid, taking into account user preferences, thereby avoiding grid overload.

[0006] JP 2014-096928 A relates to a charging plan management device for managing charging plans for power storage devices of multiple electric vehicles used by multiple users. The device stores usage histories of various electric vehicles. An estimation unit estimates the minimum required charge capacity for each electric vehicle based on the usage history, thereby determining a charging plan for each electric vehicle based on the minimum required charge capacity. Summary of the Invention

[0007] The object of the present invention is to propose a method for operating a motor vehicle during a charging process which is improved by comparison and which, in particular, does not require complex infrastructure measures.

[0008] To achieve this object, in a method of the type mentioned at the outset, it is provided according to the invention that in a control unit associated with the charging device and situated within the motor vehicle:

[0009] - receiving user information describing at least one user desire regarding the charging process,

[0010] - receiving from the charging facility via a communication connection with the charging facility energy information relating to the electrical energy provided by the charging facility,

[0011] - determining the estimated available charging time period for the charging process,

[0012] - Use of energy information related to optimization goals, time-resolved ) to determine, for the charging time period, a charging plan optimized in terms of at least one optimization target determined from the user information, and

[0013] -Carry out the charging process according to the charging plan.

[0014] The control device may, for example, be at least one controller of a motor vehicle, which is assigned to a charging device, also known as an on-board charger (OBC). The present invention utilizes the fact that modern charging facilities, or charging infrastructure, are generally standardized in terms of communication with connected motor vehicles and can transmit a large amount of useful energy information to the motor vehicle via corresponding communication protocols, such as those based on the ISO 15118 standard and / or the EEBus standard. This energy information inherently includes optimization information suitable for achieving optimization objectives for the motor vehicle. An optimization objective is understood to be the minimization or maximization of a cost function that describes at least one optimization variable. Optimization methods generally known in the prior art can be used for this purpose. In these optimization methods, the optimization parameters to be optimized are selected in such a way as to minimize or maximize the cost function. In the present case, the optimization parameters may describe how and when the vehicle's traction battery is charged by the charging facility via the charging device. Preferably, minimizing financial costs and / or maximizing green energy and / or minimizing power losses and / or minimizing CO2 emissions may be used as optimization objectives, and / or the energy information may include electricity prices and / or electricity composition and / or available charging power, broken down over time. For example, price / power information can be transmitted to the vehicle as energy information, preferably via the charging cable itself. This includes, for example, knowledge of when electricity is cheap, when particularly high charging power is available, what type of electricity is available (e.g., green electricity / renewable energy), or even whether electricity is free due to solar power usage. This energy information can be used to optimize the charging process, for example, with respect to cost, power loss (upstream emissions), green electricity, CO2 consumption, and / or the like. Accordingly, the present invention provides for creating a charging plan using all available information, in particular user-defined information, and subsequently implementing this charging plan. Based on the user's specifications and the available energy information, the charging plan is calculated in a manner that meets at least one specific optimization goal (e.g., cost-optimized and / or green electricity-optimized charging). If multiple optimization goals, in particular multiple optimization variables, are to be considered, these optimization goals can be achieved, in particular weighted, by corresponding contributions to the cost function, in particular the cost terms.

[0015] This not only enables the charging process to be tailored to user specifications and preferences, and allows for significant automation utilizing information transmitted by the charging infrastructure in accordance with modern standardization measures, but also particularly advantageously, the implementation scheme is selected so that the charging plan is determined solely within the vehicle, in particular without regard to other vehicles, so-called autarkically. Therefore, because the vehicle can autonomously determine the optimal charging strategy, there is no need for complex, defined, and / or implemented communication between the energy provider and the vehicle. The calculation of the charging plan within the vehicle is thus decentralized and independent of the infrastructure, which is only a limiting factor, for example, regarding charging power, knowledge of which is provided by energy information. Even without communication with the infrastructure, the charging process can be optimized based on cost, energy, and / or time considerations. As already mentioned, it is particularly advantageous if the energy information is transmitted via the charging cable, in particular via PLC (Power Line Communication).

[0016] The user information can be received at least partially from input devices of the vehicle, such as a man-machine interface (MMI) and / or an onboard computer, and transmitted to the control unit. However, within the scope of the present invention, it is particularly preferred to receive the user information at least partially from an application software on a mobile device and / or a desktop computer. This utilizes modern electronics to enable users to conveniently configure the autonomous charging plan optimization of the vehicle. Application software can be used in particular, which can also configure and / or control other aspects of the vehicle, such as activating the parking heater. In particular, as will be discussed in more detail below, it is also conceivable to allow charging plans to be at least partially manually created or modified via such an application software.

[0017] The end of the charging period can be conveniently determined based on charging end information contained in the user information and / or based on received schedule data of at least one user of the vehicle and / or based on a usage profile created, in particular, by analyzing historical data describing the past use of the vehicle. Thus, the user can input (perhaps at least) the desired duration for charging, while in principle, an automatic estimation of the charging period is also conceivable, either additionally or alternatively. Thus, for example, the user's schedule data can be analyzed to infer upcoming schedules for which the vehicle will be required. However, historical data can also be used to determine time-dependent usage profiles, such as whether and when the user drives to work during the week. Such estimation processes for vehicle usage, which can also at least partially utilize artificial intelligence, are generally known in the prior art and can also be advantageously utilized within the scope of the present invention.

[0018] In a particularly advantageous embodiment of the present invention, provision can be made for the charging time period to be divided into a plurality of charging intervals, particularly of equal length. Thus, the time from connecting the motor vehicle to the charging facility until the end of the charging time period is divided into time intervals or time periods that can particularly advantageously correspond to the time-dependent proportions of the energy information. In other words, an advantageous refinement of the present invention provides for the division into time periods corresponding to the optimization information in the energy information and / or based on a standard for communication between the charging device and the charging facility. For example, the energy information from the charging facility can convey the charging power, electricity price, electricity composition, etc., available at a given time. This is typically also based on a specific time discretization that can be used accordingly for the division of the charging intervals. Thus, specific, fixed optimization information exists for each charging interval, and parameter changes (e.g., cost and / or electricity composition) occur only at transitions between charging intervals. If a specification / standard is used for the communication protocol, this can already prescribe the corresponding time divisions, which are then also used by the vehicle control unit when determining the charging plan. For example, the duration of a corresponding time period that can be used as a charging interval segment can be obtained from the provisions of the ISO15118 standard.

[0019] Particularly advantageously, a cost value associated with at least one optimization objective can be determined for each charging interval of a charging time period. To determine the charging plan, the charging intervals of the charging time period can be selected sequentially for charging based on the optimization objective, such that at least one target state of charge of the power battery is achieved at least at the end of the charging interval. Thus, cost values can be determined for different time intervals based on the optimization information in the energy information, and these cost values can be aggregated into the cost term of the cost function. Such cost values can include, for example, financial costs (electricity costs), green electricity share, power losses, etc. This consideration simplifies the optimization process when optimizing according to an optimization objective (e.g., with respect to cost or with respect to the highest possible share of green electricity), as the charging intervals can ultimately be selected (filled / refilled) one by one for charging, in ascending order from the lowest cost value or descending order from the highest cost value, until the charging target is achieved.

[0020] It should be noted at this point that the target state of charge can be selected, for example, as the maximum state of charge that is reasonable with respect to the battery; it is of course also conceivable, in particular when using schedule data and / or usage profiles and / or when there is user information in this regard, to select a specific different target state of charge for the next scheduled trip.

[0021] In one advantageous embodiment of the present invention, the charging device can be designed to adjust the charging power, with the charging power being used as an optimization parameter for the charging plan. Adjusting the charging power is useful, for example, to optimize power losses in a motor vehicle and to determine different power losses at a certain charging power and, if necessary, in certain other situations—this can be determined, for example (as will be explained in greater detail) by evaluating appropriate vehicle information. Furthermore, a lower charging power may be advantageous if, for example, electricity must be used at a costly time in order to still achieve a target state of charge.

[0022] When determining the charging plan, vehicle information present in the motor vehicle regarding vehicle components involved in and / or affected by the charging process, in particular at least one characteristic curve, may also be preferably taken into account. To enable the most accurate possible calculation of the charging plan, internal vehicle knowledge in the form of vehicle information may be used. For example, characteristic curves and / or other vehicle information may be retrieved from the involved vehicle components and / or their controllers and / or already stored in the control unit. This can improve the quality of the charging plan. Relevant vehicle components or vehicle systems may include, for example, the charging device itself, the traction battery, the energy management controller, the thermal management controller, and / or correspondingly assigned actuators and / or power electronics.

[0023] In this case, a preferred refinement of the present invention provides that the vehicle information is used to determine the power loss in the motor vehicle, in particular for at least one charging power used. For example, if at least one of the at least one optimization objectives is to optimize the power loss, i.e., in particular, to minimize the power loss, the vehicle information, in particular the characteristic curve, can be used to estimate the power loss at a specific charging power, so that, for example, the charging power can be adjusted to minimize the losses. For example, the thermal management controller can provide information about the power loss that would be incurred when charging at a specific, specified charging power (e.g., 22 kW) in the current state of the motor vehicle.

[0024] The method according to the present invention can also be particularly advantageously expanded with respect to bidirectional operation, namely, the possibility of discharging the power battery into the power grid connected via the charging facility. Therefore, provision can be made for determining a charging plan that includes, in addition to the battery charging phase, also a battery discharging phase into the power grid connected via the charging facility. The benefits of the method according to the present invention are further increased when bidirectional charging is implemented, as planned discharging can also be performed according to the described principle. Specifically, provision can be made for the power battery to be operated as an intermediate storage of solar energy according to the charging plan, when connected via the charging facility to a home power grid that is also connected to a solar system that provides solar power, particularly without external energy supply costs. For example, provision can be made for charging the power battery with excess solar energy during the weekend or during the day, while at night, energy from the vehicle's power battery is used to power the home. In particular, usage profiles for the home power grid connected via the charging facility can be collected and created from this, from which consumption within the home power grid can be determined, and the bidirectional charging mode can be adjusted accordingly. For example, if the vehicle is only needed again at a significantly later time, it can be used as an intermediate storage of electrical energy during this period. It should be pointed out here that this utilization function is not limited to solar power systems, but is also conceivable, for example, to so-called collect cheap electricity and thus reduce the use of expensive electricity.

[0025] Within the scope of the present invention, it is also conceivable that when manual operating mode is selected, the user manually predefines a portion of the charging plan, particularly with the aid of the aforementioned software application. In principle, it is also conceivable for the user to create the charging plan entirely manually. This allows the user to create a charging plan and, therefore, charge in a cost-optimized manner. This is particularly advantageous if the user possesses knowledge not contained in the energy information. This knowledge, such as time limits for permitted charging, can of course also be incorporated into the automatic generation via user information. For example, the user information could specify that only nighttime electricity rates between 10 pm and 6 am should be used. For manual intervention in the charging plan, an interface is preferably provided to the user on a handheld mobile device, such as a smartphone, and / or on a desktop computer, as described above. For example, the charging plan can be manually created and / or edited in the form of a calendar.

[0026] In addition to the method, the present invention also relates to a motor vehicle having a traction battery and a charging device, and a control device assigned to the charging device, characterized in that the control device is designed to carry out the method according to the present invention. All embodiments relating to the method according to the present invention can be applied analogously to the motor vehicle according to the present invention, thereby also achieving the advantages already mentioned. The control device can include at least one memory element and at least one processor to be able to carry out the steps of the method according to the present invention. For example, the control device can have a first interface for receiving user information and a second interface for receiving energy information. Functional units for carrying out the steps of the method according to the present invention can be provided, in particular a charging time period determination unit, an optimization unit, and a control unit for carrying out the charging process according to the charging plan. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Further advantages and details of the invention will be found in the exemplary embodiments described below and based on the drawings.

[0028] The accompanying drawings show:

[0029] Figure 1 shows a flow chart of an embodiment of a method according to the present invention,

[0030] Figure 2 shows a schematic diagram of the principle of a motor vehicle according to the present invention,

[0031] Figure 3 shows the functional structure of a motor vehicle control device, and

[0032] Figure 4 A motor vehicle is shown connected to a domestic electrical grid via a charging facility. DETAILED DESCRIPTION

[0033] Figure 1 A flow chart of an embodiment of a method according to the invention is shown, which is used to operate a motor vehicle while performing a charging process of a power battery of the motor vehicle, from which an electric motor for driving the motor vehicle can be supplied with power. The power battery is connected to a charging facility, such as a charging station, a wall box, etc., via a charging device of the motor vehicle, which is assigned a control device, and which provides charging power from an electrical grid, such as a household electrical grid. This connection can be carried out in particular via a charging cable. Communication can also be carried out via the charging cable or by other means according to a communication protocol, for example according to the ISO15118 standard, within the framework of which the control device assigned to the motor vehicle charging device in the motor vehicle obtains energy information from the charging facility. This energy information can, for example, include electricity prices broken down over time, the available charging power, the available electricity composition (in particular with regard to green electricity), etc. According to Figure 1, receiving this energy information in step S1. In step S2, especially significantly earlier, user information is also received via a corresponding interface of the control unit, for example from an input device in the vehicle itself, but preferably from, for example, a tablet or smartphone and / or a desktop computer via a wireless interface of the vehicle. In any case, the user information includes user specifications regarding the optimization objective according to which the charging process should be performed optimally. Multiple optimization objectives can also be used, particularly in a weighted manner. Optimization objectives include, for example, the lowest possible financial costs, the lowest possible power loss, the highest possible share of green electricity, the lowest possible CO2 emissions from power generation, etc. The user information may also include charging end information, which describes the expected length of the charging period according to the user's plan. Other user specifications may also be part of the user information, such as restrictions on the time of day charging should occur and / or restrictions on the target state of charge of the traction battery. Furthermore, when the traction battery can be discharged into the power grid (bidirectional charging), the user information may also include specifications regarding whether the vehicle is to be used as a temporary storage device for electrical energy.

[0034] In step S3, the available charging time period is determined or estimated. If the user information does not contain information about the end of charging, for example, the user's schedule data, which may also be present in a mobile device and / or a desktop computer, may be used for this purpose. Alternatively and / or additionally, a usage profile determined by analyzing historical data describing the past use of the vehicle may also be used.

[0035] Then, in step S4, a charging plan is determined for the charging time period of step S3 based on the information obtained in steps S1 and S2. This determination of the charging plan and its execution in step S5 takes place exclusively in the vehicle, specifically in the control unit, so that the vehicle can, so to speak, autonomously determine and apply the optimal charging strategy.

[0036] In step S4, not only the time period during which charging is to take place, in particular the individual charging intervals, but also the charging power to be used is used as an optimization parameter, wherein various approaches can be used for the optimization method. A cost function can be minimized or maximized, wherein the cost function can, in particular, describe optimization variables related to the optimization objective—for example, the proportion of green electricity, financial costs, etc. If there are multiple optimization objectives and thus multiple optimization variables, these can be combined in a weighted manner into the cost function.

[0037] In step S4, the charging time period is first divided into a plurality of time periods, i.e., charging intervals. This division is based on the division on which the energy information is based, so that a parameter of the energy information can be clearly assigned to each time interval. For example, the time division according to ISO 15118 can be used.

[0038] In a specific design, each charging interval can be assigned information such as available charging power, the financial cost of electricity, and the composition of the electricity. The energy information share used subsequently ultimately depends on at least one optimization objective to be used, i.e., it includes parameters from which the optimization variables assigned to the optimization objective can be derived. Therefore, this energy information share should be referred to as optimization information. Based on the division into charging intervals and the clear assignment of optimization information to each time interval, the cost value of the optimization variable can be easily determined for each time interval, on which optimization can be performed.

[0039] In a specific design, when only one optimization objective is set, it can be specified that charging intervals are selected sequentially for charging, for example, in ascending order from the lowest cost value when minimizing, or in descending order from the highest cost value when maximizing. For example, if the goal is to minimize financial costs, the charging intervals with the lowest cost (i.e., the lowest cost value) can be considered first for charging, and then filled in ascending order until the target state of charge is reached. A similar approach can of course be used for other optimization objectives (such as maximizing the share of green electricity, etc.).

[0040] In a preferred embodiment, in addition to user and energy information, vehicle information—that is, internal knowledge of the vehicle—can also be used. This vehicle information can include, for example, characteristic curves, but can also include other useful data. For example, if the optimization is at least partially aimed at minimizing power loss in the vehicle, the vehicle information can include data, such as provided by the vehicle's thermal management system, on the power loss expected at a given charging power given the vehicle's current state. However, in addition to using power loss as an optimization criterion, the consideration of vehicle information also enables more precise and higher-quality determination of the charging plan, as it can, for example, determine how much of the absorbed electrical power is actually used to increase the state of charge in the traction battery.

[0041] As already mentioned, if "bidirectional charging" is possible, a charging plan can also be determined accordingly. In this case, user information is also particularly advantageously used to provide usage information on the home power grid, from which the control device can infer that solar energy should be collected from the solar system during the day when no one is at home and everyone is at work, and can then be used again in the evening.

[0042] In step S5 , as described above, the control device uses the charging plan to implement the charging process according to the charging plan, and then performs charging in particular in the charging intervals in which charging is to be performed, and optionally at a corresponding charging power.

[0043] Figure 2 A simplified schematic diagram of a motor vehicle 1 according to the present invention is shown. In the present case, the motor vehicle 1 is designed as an electric vehicle, and has an electric motor 2 that can be fed by a power battery 3 (a high-voltage battery, for example, with a voltage of 400 V). When connected to a charging facility via a charging connector 5, the power battery 3 can be charged by a charging device 4 (on-board charger - OBC). As described, the charging device 4 installed in the motor vehicle 1 is assigned a control device 6 that is designed to execute the method according to the present invention.

[0044] Figure 3 The functional structure of the control device 6 is shown in greater detail. The control device first includes a storage component 7, which can store required information, such as user information, energy information, vehicle information, and a determined charging plan. User information can be received via a first interface 8, and energy information can be received via a second interface 9. The charging time period determination unit 10 determines a charging time period according to step S3. Then, the optimization unit 11 determines a charging plan according to step S4. The control unit 12 uses the determined charging plan to control the charging device 4 according to step S5, thereby implementing the charging plan.

[0045] at last, Figure 4 The diagram shows a motor vehicle 1 connected to a charging facility 14, for example, in a garage, by means of a charging connector 5 via a charging cable 13. Energy information can also be transmitted via the charging cable 13 according to a standardized communication protocol. The charging facility 14 supplies charging power from an electrical grid 17, which is designed here as a household electrical grid 15 assigned to a house 16. A solar system 18 is also connected to the electrical grid 17. Furthermore, the electrical grid 17 is connected to another electrical grid, namely a general energy supply network 19. Using the method described here, in this configuration, the traction battery 3 can also be used in bidirectional charging mode as a buffer for the free, self-generated solar energy (more precisely, solar electricity) of the solar system 18.

Claims

1. A method for operating a motor vehicle (1) during a charging process of a power battery (3) of the motor vehicle (1), wherein: The power battery (3) is connected to a charging facility (14) outside the motor vehicle via a charging device (4) of the motor vehicle (1), and is characterized in that: In a control unit (6) assigned to a charging device (4) and arranged inside a motor vehicle (1): - receiving user information describing at least one user desire regarding the charging process, - receiving energy information related to the electrical energy provided by the charging facility (14) from the charging facility (14) via a communication connection with the charging facility (14), - determining the estimated available charging time period for the charging process, - using the time-resolved optimization information of the energy information, which is relevant to the optimization target, to determine, for the charging time period, a charging plan that is optimized with respect to at least one optimization target determined from the user information, and - Carry out the charging process according to the charging plan, Using green power maximization and / or power loss minimization and / or carbon dioxide emission minimization as optimization objectives, the energy information includes electricity prices segmented over time and / or electricity composition segmented over time and / or available charging power segmented over time, The charging plan is determined only in the motor vehicle (1), Divide the charging time period into multiple charging intervals. A cost value associated with at least one optimization objective is determined for each charging interval of a charging time period, and in order to determine a charging plan, the charging intervals of the charging time period are sequentially selected for charging according to the optimization objective, so that at least one target state of charge of the power battery (3) is achieved at least at the end of the charging time period.

2. The method according to claim 1, characterized in that User information is received at least in part from an input device of the motor vehicle (1) and / or from application software of a mobile device and / or a desktop computer.

3. The method according to claim 1 or 2, characterized in that The end of the charging period is determined based on charging end information contained in the user information and / or based on received schedule data of at least one user of the motor vehicle (1) and / or based on a usage profile created by analyzing historical data describing the past use of the motor vehicle (1).

4. The method according to claim 1 or 2, characterized in that The plurality of charging intervals are of equal length.

5. The method according to claim 1, wherein The division is performed according to division into time periods corresponding to the optimization information in the energy information, and / or the division is performed according to a standard for communication between the charging device and the charging facility.

6. The method according to claim 1 or 2, characterized in that The charging device (4) is designed to adjust the charging power, wherein the charging power is used as an optimization parameter for the charging plan.

7. The method according to claim 1 or 2, characterized in that When determining the charging plan, vehicle information present in the motor vehicle (1) about vehicle components involved in and / or affected by the charging process is also taken into account, the vehicle information being at least one characteristic curve.

8. The method according to claim 7, characterized in that The vehicle information is used to determine a power loss in the motor vehicle (1), the power loss being determined for at least one charging power used.

9. The method according to claim 1 or 2, characterized in that A charging plan is determined, which includes, in addition to a charging phase of the battery, a discharging phase of the battery into a power grid (17) connected via a charging facility (14).

10. The method according to claim 9, characterized in that When connected to a household electrical network (15) via a charging facility (14), which is also connected to a solar device (18) that provides solar power, the power battery (3) is operated as an intermediate storage for solar energy according to a charging plan.

11. The method according to claim 1 or 2, characterized in that When the manual operating mode is selected, a part of the charging plan is manually specified by the user.

12. The method according to claim 1 or 2, characterized in that The charging plan is determined without taking other motor vehicles into consideration.

13. A motor vehicle having a power battery (3) and a charging device (4) and a control device (6) assigned to the charging device, characterized in that The control device (6) is designed to carry out the method according to any one of claims 1 to 12.

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