Method for operating motor vehicle, corresponding motor vehicle and computer program product

Abstract

The invention relates to a method for operating a motor vehicle having an electric drive, a power battery which is electrically connected to the electric drive, and a charging interface which is electrically connected to the power battery via a switching device, the switching device is opened in a first switching state to interrupt an electrical connection between the power battery and the charging interface, and is closed in a second switching state to establish the electrical connection. When the switching device is adjusted to the second switching state, the charging power is determined during the charging of the power battery with the electrical energy provided at the charging interface, and the charging of the power battery is ended when the charging power is below a power threshold value. A time interval until the power battery is recharged is determined in a predictive manner on the basis of at least one state variable, the switching device is kept in the second switching state if the time interval is below a time threshold value, and the switching device is adjusted to the first switching state if the time interval exceeds the time threshold value. The invention also relates to a motor vehicle and a computer program product.

Description

TECHNICAL FIELD

[0001] The invention relates to a method for operating a motor vehicle having an electric drive device, a power battery electrically coupled to the drive device, and a charging interface electrically coupled to the power battery by means of a switching device, wherein the switching device is open in a first switching state to interrupt an electrical connection between the power battery and the charging interface, and is closed in a second switching state to establish the electrical connection. The invention also relates to a motor vehicle and to a computer program product. BACKGROUND

[0002] From the prior art, for example, the document DE 10 2022 126 413 A1 is known. This document describes a vehicle charging system comprising a contactor system containing at least one contactor and a control module programmed to command the at least one contactor to remain in a closed position at vehicle standstill when a charging event is predicted to be likely to occur after vehicle standstill. The at least one contactor, in the closed position, operably connects a power battery pack with a charging interface assembly of the vehicle charging system. For example, the at least one contactor remains in the closed position for a threshold amount of time after vehicle standstill. Preferably, the threshold amount of time is at least two minutes.

[0003] Furthermore, the document DE 10 2022 119 768 A1 discloses a method for charging an electrically powered vehicle, wherein a preset value of a charging current intensity or a charging power of a charging current taken up by the electrically powered vehicle is specified in time by means of a charging control device of the electrically powered vehicle.

[0004] Furthermore, the document DE 10 2011 089 230 A1 discloses a charging device for an electrically powered vehicle, which can be coupled to a power supply system of a building and has at least one data interface for receiving energy generation data, which contain information about the electrical energy provided by an energy generation device of the building to the power supply system. It is provided here that the at least one data interface is designed to receive consumption data, which contain information about the electrical energy taken up by at least one consumer of the building from the power supply system, and to charge an electrical energy store of the electrically powered vehicle in dependence on the energy generation data and the consumption data. SUMMARY

[0005] It is an object of the invention to propose a method for operating a motor vehicle, which has advantages over known methods, in particular enables charging of a power battery with low wear of a switching device and with varying electrical power of an electrical source.

[0006] According to the application, this is achieved by a method for operating a motor vehicle having the features of claim 1. It is provided that, in the event of the switching device being adjusted to the second switching state, during charging of the traction battery with electrical energy provided at the charging interface, the charging power is determined, charging of the traction battery being ended in the event of the charging power falling below a threshold value, wherein a time interval until the traction battery is recharged is determined in a predictive manner on the basis of at least one state variable, and if this time interval falls below a time threshold value, the switching device is maintained in the second switching state, and if this time interval exceeds the time threshold value, the switching device is adjusted to the first switching state.

[0007] Advantageous design schemes of the application with suitable refinements are given in the dependent claims. It is pointed out that the embodiments set forth in the description are not restrictive; rather, any variant of the features disclosed in the description, in the claims and in the drawings can be realized.

[0008] The method serves for operating a motor vehicle. The motor vehicle has at least an electric drive device, a traction battery, a switching device and a charging interface. The electric drive device serves for driving the motor vehicle, and thus for providing a drive torque intended to drive the motor vehicle. In order to provide the drive torque, the drive device has at least one drive unit which is designed as a traction electric machine. The motor vehicle can be designed as an electric vehicle or as a hybrid vehicle. In the latter case, in addition to the traction electric machine, the motor vehicle has a further drive unit, for example in the form of an internal combustion engine.

[0009] The traction electric machine is electrically coupled to the traction battery and is at least temporarily operated with electrical energy taken from the traction battery. It can additionally be provided that the energy provided by means of the traction electric machine is temporarily stored in the traction battery. The traction battery is sometimes charged with electrical energy provided by an external electrical source, for example a charging station or the like. To this end, the motor vehicle has a charging interface, for example in the form of a charging socket or the like, and is connectable to the electrical source. The charging interface is electrically coupled to the traction battery by means of the switching device. The switching device has at least one switch, i.e. for example only one single switch or a plurality of switches.

[0010] In the present description, if reference is made to the switching device, this always refers to the at least one switch. The at least one switch is preferably a contactor. The switching device, more precisely the at least one switch, serves for selectively establishing or interrupting the electrical connection between the traction battery and the charging interface. To this end, the switching device is adjustable to different switching states, i.e. at least a first switching state and a second switching state. In the first switching state, the electrical connection between the traction battery and the charging interface is interrupted, and in the second switching state, the electrical connection between the traction battery and the charging interface is established.

[0011] In order to charge the traction battery using the electrical energy provided at the charging interface, the switching device needs to be adjusted to the second switching state. It is preferably provided that the traction battery is electrically connected to an intermediate circuit by means of the switching device, which intermediate circuit is also electrically connected to the drive device and to the charging interface. If the switching device is in the first switching state, the traction battery is electrically disconnected from the intermediate circuit, whereas in the second switching state it is electrically connected to the intermediate circuit.

[0012] Thus, in order to perform a driving operation of the motor vehicle, during which a non-zero drive torque is provided by the drive device, and in order to charge the traction battery with electrical energy provided externally, the switching device must be closed and accordingly in the second switching state. On the other hand, outside of the driving operation and the charging, the switching device is adjusted to the first switching state in order to interrupt the electrical connection between the traction battery and the charging interface or the intermediate circuit. This serves on the one hand to achieve a high level of safety for the motor vehicle and on the other hand to avoid an undesired discharge of the traction battery.

[0013] Thus, it is in principle provided that the switching device is adjusted to the second switching state during charging of the traction battery and to the first switching state in the event of the end of the charging. If the traction battery subsequently needs to be charged again or to continue to be charged, the switching device must be switched from the first switching state to the second switching state again. If the traction battery is charged with electrical energy from an electrical power source that fluctuates, it can occur that the charging is ended due to a too low charging power and the switching device is accordingly switched from the second switching state to the first switching state. If sufficient electrical power is subsequently available again, the charging is resumed and for this purpose the switching device is switched from the first switching state to the second switching state. This can result in the switching device being switched very frequently between the first switching state and the second switching state and vice versa. As a result, a severe wear of the switching device can occur.

[0014] Thus, according to the application it is provided that during charging of the traction battery using the electrical energy provided at the charging interface, at which time the switching device is adjusted to the second switching state, a charging power is determined. The charging power is to be understood as meaning the electrical power with which the traction battery is charged during the charging. If the charging power at least corresponds to a power threshold value, i.e. is equal to or greater than the power threshold value, the charging of the traction battery is continued until the charging level of the traction battery corresponds to a desired charging level.

[0015] If, on the contrary, the charging power is below the power threshold value, i.e. is less than the power threshold value, the charging of the traction battery is ended. In this case, the switching device would normally be switched from the second switching state to the first switching state. According to the application, however, it is proposed that first a time interval is determined from at least one state variable, which time interval describes an estimated length of time after which the traction battery can be charged again as a result of a sufficiently large electrical power being provided again at the charging interface.

[0016] If the time interval is less than a time threshold, the switching device remains in the second switching state, i.e., it does not switch to the first switching state. If it is anticipated that the battery can be recharged after only a short period of time, the switching device is not disconnected, and the battery remains electrically connected to the charging interface or intermediate circuit. Conversely, if the time interval exceeds the time threshold, i.e., the time interval is greater than or equal to the time threshold, the switching device is switched from the second switching state to the first switching state according to common practice, and the electrical connection between the battery and the charging interface or intermediate circuit is interrupted accordingly.

[0017] This approach makes particular sense if the electrical energy supplied at the charging port is in the form of renewable energy, such as energy provided by a photovoltaic (PV) device. It is especially meaningful if at least one other power consumer is electrically connected to the PV device and operates using the electrical energy supplied by the PV device. In this case, the battery should only be charged with a portion of the electrical energy supplied by the PV device—that is, the excess electrical energy still available after powering at least one other power consumer.

[0018] In other words, the power battery is charged using only the equivalent of excess power, specifically, the power supplied by the photovoltaic equipment minus the power required for the operation of at least one power consumer. Because both the power supply and the power consumer vary over time, this typically results in frequent switching of the switching devices between their switching states, and consequently, high wear on the switching devices. This is reliably avoided by the method described.

[0019] The improved embodiment of the present invention specifies the use of electrical energy generated by a photovoltaic device to charge a power battery. This practice has already been mentioned. The photovoltaic device converts solar energy into electrical energy and provides this electrical energy at a defined power level, referred to as the power supply power. The power supply power can change rapidly due to environmental conditions, such as weather conditions and shading. Therefore, the described method is particularly advantageous when using a photovoltaic device to provide electrical energy.

[0020] The improved embodiment of the present invention specifies that both the vehicle's charging interface and the photovoltaic device are connected to the same power inlet of the building. The photovoltaic device is attached to the building, i.e., particularly arranged at the building or at least in the building environment. For example, the photovoltaic device is located on the roof of the building. Both the photovoltaic device and the vehicle's charging interface are electrically connected to the building's power inlet. For example, the charging interface is electrically connected to a charging device at a certain distance from the vehicle, particularly in a continuously conductive or wired connection or at least partially wireless connection.

[0021] The charging device takes the form of a wall-mounted charging box and is connected to the home access interface. This means that the wall-mounted charging box is powered by the photovoltaic equipment, the home access interface, or both. Particularly advantageously, it supplies power only to the charging device the electricity provided by the photovoltaic equipment and not needed by at least one other consumer appliance. Therefore, the advantages of the described approach are particularly evident.

[0022] An improved embodiment of the present invention specifies that the time interval is determined using a predicted change curve of at least one state parameter. This means that instead of using only the instantaneous value of the state parameter, multiple values ​​are used to determine the time interval. The multiple values ​​of the state parameter describe the time-varying curve of the state parameter, particularly the future change curve. In this sense, the change curve of the state parameter is a time-varying curve and includes future state parameter values ​​from the current moment. Based on the predicted change curve of the state parameter, the future availability of charging power can be determined with particular precision.

[0023] An improved embodiment of the present invention specifies that, as at least one state parameter, the photovoltaic power of the photovoltaic equipment and / or the building demand power of the building and / or the excess power determined from the photovoltaic power and the building demand power are used. The photovoltaic power is equivalent to the power supply already mentioned and provides the electrical power provided by the photovoltaic equipment. The building demand power describes the electrical power required by the building, more specifically, by at least one power-consuming appliance.

[0024] Similarly, excess power can be used as a state parameter. Excess power is the difference between the photovoltaic (PV) power and the building's required power, and describes the power difference when the PV power exceeds the building's required power. The lower limit of excess power is preferably limited to zero; therefore, if the building's required power is greater than the PV power, the excess power is zero; otherwise, the excess power corresponds to the difference between the PV power and the building's required power. It can be specified that only one of the above parameters is considered as a state parameter. However, it is particularly preferred to use multiple or even all of the above parameters to achieve particularly precise determination of time intervals.

[0025] The improved embodiment of this invention stipulates that after charging ends, if the available electrical power exceeds another power threshold, charging is resumed. Therefore, when the charging power is below the power threshold, charging is not completely interrupted, but only paused or suspended. If the available electrical power at the charging port is again sufficient to continue charging the power battery, charging is resumed or continues. Then, the power battery is charged, especially until the power battery's charging level meets the desired charging level or the charging power falls below the power threshold again.

[0026] If the electrical power exceeds, i.e., is greater than, another power threshold, charging resumes. This other power threshold can be equal to the power threshold already mentioned, but is preferably different from it. For example, this other power threshold is chosen to be greater than the power threshold, such that the termination and resumption of charging are delayed based on the available electrical power. This reliably avoids excessively frequent termination and resumption of charging. In summary, the advantages already mentioned are achieved through the described approach.

[0027] The improved embodiment of the present invention specifies that, in order to resume charging, if the switching device is in a first switching state, it is adjusted to a second switching state; if the switching device is in the second switching state, it is maintained in the second switching state. In this respect, when resuming charging, it is distinguished whether the switching device is in the first switching state or the second switching state. In each case, the switching device is adjusted to subsequently be in the second switching state. Therefore, the power battery can be easily charged using the electrical energy provided at the charging interface.

[0028] The improved embodiment of the present invention specifies that, to terminate charging, the charging power is adjusted to a lower first value by regulating the charging equipment of the vehicle, and when charging resumes, the charging power is adjusted to a higher second value. The charging equipment is preferably an integral part of the vehicle, but may also be part of a charging device or charging station. The charging equipment controls the charging power, that is, the electrical power supplied from the charging interface to the power battery.

[0029] If charging of the power battery is terminated due to the charging power falling below the power threshold, then although an electrical connection is still established between the power batteries and their charging interfaces, no electrical energy should be supplied, or only a small amount of electrical energy should be supplied. Accordingly, in this case, the charging power is adjusted to a first value. If charging resumes due to sufficient available power, the charging power is adjusted to a second value. The second value is greater than the first value. Preferably, the first value is equal to zero or at least close to zero. The described approach achieves the advantages already presented.

[0030] The present invention also relates to a motor vehicle, particularly for performing a method according to an embodiment described herein, wherein the motor vehicle has an electric drive unit, a power battery electrically connected to the electric drive unit, and a charging interface electrically connected to the power battery via a switching device, wherein the motor vehicle is configured and designed such that the switching device is opened in a first switching state to interrupt the electrical connection between the power battery and the charging interface, and closed in a second switching state to establish the electrical connection.

[0031] Here, the motor vehicle is also configured and designed to determine the charging power during the charging of the power battery using electrical energy provided at the charging interface when the switching device is adjusted to the second switching state, and to end the charging of the power battery when the charging power is lower than a power threshold. In this case, the time interval until the power battery is recharged is predicted based on at least one state parameter. If the time interval is lower than a time threshold, the switching device is kept in the second switching state. If the time interval exceeds the time threshold, the switching device is adjusted to the first switching state.

[0032] The advantages of these design schemes or practices for motor vehicles have already been pointed out. Motor vehicles and methods for operating them can be improved based on the descriptions in the specification, and reference can be made to these descriptions in this regard. Of course, the invention also relates to a motor vehicle combination system having the described motor vehicle, and additionally having, for example, photovoltaic equipment and / or power access interfaces and / or buildings and / or charging devices. The invention also relates to a method for operating such a motor vehicle combination system.

[0033] This invention also relates to a computer program product comprising instructions that cause a motor vehicle according to an embodiment of this specification to perform the described method. Advantages and feasible advantageous modifications can be fully referenced in this specification.

[0034] The features and combinations thereof described in this specification, especially those described and / or shown in the following description of the drawings, can be used not only in their respective given combinations, but also in other combinations or individually, without departing from the scope of the invention. Therefore, even embodiments not explicitly shown or described in the specification and / or drawings, but disclosed or derived from the described embodiments, should be considered part of the invention. Attached Figure Description

[0035] The invention will now be described in more detail with the aid of embodiments shown in the accompanying drawings, but these embodiments do not constitute a limitation thereof. Here, the only accompanying drawings are shown:

[0036] Figure 1 A schematic diagram of a motor vehicle assembly system is shown, which includes a motor vehicle having a power battery that is charged using electrical energy supplied via the motor vehicle's charging interface.

[0037] List of reference numerals

[0038] 1. Motor vehicle combination system

[0039] 2 Motor vehicles

[0040] 3 Charging ports

[0041] 4. Charging cable

[0042] 5. Charging device

[0043] 6. In-home interface

[0044] 7 buildings

[0045] 8. Photovoltaic equipment

[0046] 9 Photovoltaic Modules Detailed Implementation

[0047] This invention relates to a vehicle combination system 1, which includes a vehicle 2 having a drive unit (not shown) and a power battery (also not visible). The vehicle 2 has a charging interface 3 through which electrical energy is supplied, at least temporarily, to charge the power battery. In the illustrated embodiment, the charging interface 3 is electrically connected, for example via a charging cable 4, to a charging device 5, such as a wall-mounted charging box. The charging device 5 is electrically connected to an entrance interface 6 of a building 7 (shown only here). Similarly, a photovoltaic device 8, for example having multiple photovoltaic modules 9, is also connected to the entrance interface 6 and therefore to the charging device 5.

[0048] A switching device (not shown) is electrically connected between the charging interface 3 and the power battery. This switching device can be adjusted to different switching states; therefore, in the first switching state, the electrical connection between the power battery and the charging interface 3 is interrupted, while in the second switching state, the electrical connection between the power battery and the charging interface 3 is established. To charge the power battery, electrical energy generated by the photovoltaic device 8 should be supplied to the charging interface 3 via the charging device 5. In particular, only the portion of electrical energy not required for the operation of the building 7, such as the operation of appliances not required for the building 7, should be used to charge the power battery. In this respect, only the excess power from the photovoltaic power of the photovoltaic device 8 exceeding the building's required power is supplied via the charging interface 3.

[0049] If the available charging power is lower than the power threshold during the charging of the power battery, charging should be paused first. Furthermore, the expected time interval before the power battery is recharged is determined based on at least one state parameter. If this time interval is less than the time threshold, the switching device is held in a second switching state, thereby maintaining the electrical connection between the charging interface 3 and the power battery accordingly. If the subsequently available electrical power exceeds the power threshold or another power threshold, charging of the power battery continues.

[0050] Conversely, if the time interval exceeds a time threshold, charging is completely terminated, and the switching device is switched from the second switching state to the first switching state, thereby interrupting the electrical connection between the charging interface 3 and the power battery. This approach prevents the switching device from switching too frequently, thereby reducing the wear and tear associated with the switching device.

Claims

1. Method for operating a motor vehicle (2) having an electric drive device, a power battery electrically coupled to the electric drive device, and a charging interface (3) electrically coupled to the power battery by means of a switching device, wherein The switching device is opened in the first switching state to interrupt the electrical connection between the traction battery and the charging interface (3) and is closed in the second switching state to establish the electrical connection, characterized in that, in the event of a regulation of the switching device into the second switching state, during charging of the traction battery with electrical energy provided at the charging interface (3), a charging power is determined, charging of the traction battery is ended in the event of the charging power falling below a power threshold, wherein a time interval until the traction battery is recharged is determined predictively from at least one state variable, the switching device is maintained in the second switching state if the time interval falls below a time threshold, and the switching device is regulated into the first switching state if the time interval exceeds the time threshold.

2. The method of claim 1, wherein, The traction battery is charged using electrical energy generated by the photovoltaic device (8).

3. The method according to any of the preceding claims, characterized in that, The charging interface (3) of the motor vehicle (2) and the photovoltaic device (8) are both coupled to a same electricity supply connection (6) of the building (7).

4. The method according to any of the preceding claims, characterized in that, The time interval is determined using a predicted change curve of the at least one state variable.

5. The method according to any of the preceding claims, characterized in that, As the at least one state variable, the photovoltaic power of the photovoltaic device (8) and / or the building demand power of the building (7) and / or the excess power determined from the photovoltaic power and the building demand power are used.

6. The method according to any of the preceding claims, characterized in that, After ending the charging, the charging is resumed if the available electrical power exceeds a further power threshold.

7. The method according to any of the preceding claims, characterized in that, For resuming the charging, the switching device is regulated into the second switching state if the switching device is in the first switching state and is maintained in the second switching state if the switching device is in the second switching state.

8. The method according to any of the preceding claims, characterized in that, For ending the charging, the charging power is regulated to a lower first value by a regulation of the charging device of the motor vehicle (2), and for resuming the charging, the charging power is regulated to a higher second value.

9. Motor vehicle (2), in particular for carrying out the method according to one or more of the preceding claims, wherein The motor vehicle (2) has an electrical drive device, a traction battery electrically coupled to the electrical drive device, and a charging interface (3) electrically coupled to the traction battery by means of a switching device, wherein the motor vehicle (2) is provided and designed such that the switching device is opened in the first switching state to interrupt the electrical connection between the traction battery and the charging interface (3) and is closed in the second switching state to establish the electrical connection, characterized in that the motor vehicle (2) is further provided and designed such that, in the event of a regulation of the switching device into the second switching state, during charging of the traction battery with electrical energy provided at the charging interface (3), a charging power is determined, charging of the traction battery is ended in the event of the charging power falling below a power threshold, wherein a time interval until the traction battery is recharged is determined predictively from at least one state variable, the switching device is maintained in the second switching state if the time interval falls below a time threshold, and the switching device is regulated into the first switching state if the time interval exceeds the time threshold.

10. A computer program product comprising instructions for causing a motor vehicle (2) according to claim 9 to carry out a method according to one or more of claims 1 to 8.

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