Method for operating a motor vehicle that is at least partially electrically powered and motor vehicle

Abstract

Method for operating a motor vehicle (1) that is at least partially electrically powered, comprising a battery system (2), a charging system (3) and a high-voltage electrical system (4) with high-voltage components (14).The procedure comprises the following steps: Requesting operation of the high-voltage component (14) during the charging process; shutting down the high-voltage electrical system (14) to a de-energized state, in which the high-voltage electrical system (4) is disconnected from the battery system (2); maintaining the charging process so that an AC voltage from the AC power source (33) is present at the input (13) of the charging device (3) and no power is transferred to the high-voltage electrical system (4) at the output (23) of the charging device (3); connecting the high-voltage component (14) to the high-voltage electrical system (4); starting up the high-voltage electrical system (4) so ​​that the connected high-voltage component (14) is supplied with energy from the battery system (2); continuing the charging process with power transfer from the charging device (3) to the high-voltage electrical system (4).

Description

[0001] The present invention relates to a method for operating a motor vehicle that is at least partially electrically powered and to a motor vehicle. The motor vehicle comprises a battery system and a charging device for charging the battery system with alternating current from an external alternating current source. The motor vehicle comprises a high-voltage electrical system, which can be supplied with electrical energy by the battery system and includes at least one high-voltage component.

[0002] In such a vehicle, from an energy perspective, it makes sense to reduce the operating time of the high-voltage components that are not needed for the charging process. Therefore, the high-voltage components are usually switched off during the charging process.

[0003] However, a disadvantage of this is that the high-voltage components, which are switched off during the charging process, are also unavailable for other uses. For example, the electric drive system is completely switched off during charging. This means the drive system cannot be used to heat the vehicle (so-called drive heating).

[0004] For safety reasons, reactivating the deactivated high-voltage components during charging is only possible if the charging process is completely aborted or shut down. However, this leads to an undesirable delay in the charging process and can sometimes trigger unwanted error messages from the charging station. Another problem is that if you are charging at a charging station that required manual activation (e.g., a public charging point), the charging process cannot be automatically restarted after it has been aborted.

[0005] DE 10 2022 003 931 A1 discloses a method and a device for charging the high-voltage system of a commercial vehicle body using an AC charging device with an AC / DC converter. The AC / DC converter is electrically coupled to an energy smoothing device, which is electrically coupled to a DC / DC converter. The DC / DC converter is electrically coupled to the vehicle's high-voltage system. The AC charging device has a branch with a high-voltage connection, which is electrically coupled to an electrical connection between the AC / DC converter and the energy smoothing device, and to which the vehicle body is at least temporarily connected.

[0006] From DE 10 2021 101 600 A1, an electrical system for a motor vehicle and a method for operating the electrical system are known. The electrical system has a control unit, an energy storage device, and several components that can be operated via the energy storage device. The electrical system is divided into two subnetworks, each of which is assigned one of the components. The control unit can switch the subnetworks on and off via switching devices depending on operating status information that describes the current operating state of the motor vehicle.

[0007] German patent application DE 10 2019 007 030 A1 discloses an electrical system for an electric vehicle comprising a high-voltage energy storage device, a DC charging port, a high-voltage drive component, and a low-voltage component. The low-voltage component is supplied by the high-voltage energy storage device and is coupled to an isolating first high-voltage-to-low-voltage converter and an isolating second high-voltage-to-low-voltage converter. Each of the high-voltage-to-low-voltage converters is coupled to the high-voltage energy storage device via a switching device.

[0008] In contrast, the object of the present invention is to provide an improved method for charging a motor vehicle. In particular, the operating times of the high-voltage components during the charging process should be kept as short as possible. At the same time, the functions of the high-voltage components should also be available during the charging process.

[0009] This problem is solved by a method having the features of claim 1. A motor vehicle according to the invention is the subject of claim 9. Preferred embodiments of the invention are the subject of the dependent claims. Further advantages and features of the present invention will become apparent from the general description and the description of the exemplary embodiment.

[0010] The method according to the invention serves to operate a motor vehicle that is at least partially electrically powered, and for example, an electric vehicle and / or hybrid vehicle. The motor vehicle is, in particular, a passenger car. The motor vehicle comprises a battery system and a charging device for charging the battery system with alternating current from an external alternating current source during a charging process (so-called AC charging). The motor vehicle comprises a high-voltage electrical system with at least one high-voltage component, which can be supplied with electrical energy by the battery system. The charging device comprises an input and an output. The charging device can be connected to the alternating current source at the input. The charging device is connected to the high-voltage electrical system at the output. In particular, the battery system is charged during the method with alternating current from the external alternating current source by means of the charging device.The procedure includes at least the following steps: making and / or registering a request for the operation of the at least one high-voltage component during the charging process (in other words, during the charging process a function of the at least one high-voltage component is requested or...registered); in particular, the high-voltage component is disconnected from the high-voltage electrical system at least at the time of its operation; shutdown of the high-voltage electrical system to a voltage-free state in which the high-voltage electrical system is (galvanically) isolated from the battery system; maintenance of the charging process so that an alternating voltage from the alternating current source is present at the input of the charging device and no power is transferred to the high-voltage electrical system at the output of the charging device; connection of the high-voltage component to the high-voltage electrical system; startup of the high-voltage electrical system so that the high-voltage electrical system and thus also the connected high-voltage component are supplied with energy by the battery system; continuation of the charging process with power transfer through the charging device to the high-voltage electrical system (so that the battery system is charged).

[0011] The present invention offers many advantages. A significant advantage is the ability to shut down the high-voltage electrical system and maintain the charging process while the high-voltage component is being switched on. This allows the high-voltage components to be switched on safely and reliably as needed, ensuring their functions remain available even during charging. For example, drive heating can be performed during charging. Furthermore, switching on the components as needed avoids unwanted or unnecessary operating times during AC charging. In addition, the invention is structurally simple to implement and can be easily integrated into existing or previously developed motor vehicles.

[0012] Preferably, a request for heating via the high-voltage component is made and / or registered during the charging process. In particular, the operation of a high-voltage component is requested, which can generate heat through its operation. A request for another function of the high-voltage component is also possible.

[0013] In a particularly preferred embodiment, the at least one high-voltage component is designed as an electric drive unit. Preferably, heating is then achieved by selectively supplying current to the drive unit. In particular, the drive unit comprises at least one electric machine. Preferably, heating is achieved by selectively generating losses in the electric machine (without generating torque). Heating can also be achieved by supplying current to a high-voltage component of a different design.

[0014] Heating can be used, for example, to temper the drive system and / or the battery system and / or a coolant system and / or the interior of the vehicle to a desired temperature during the charging process.

[0015] It is possible and advantageous for at least one high-voltage component to be designed as an electric chassis control unit. Preferably, a request to actuate the electric chassis control unit during the charging process is made and / or registered. For example, the actuation may be for chassis adjustment or the like.

[0016] The high-voltage electrical system can comprise at least two and preferably a plurality of high-voltage components. One or more of these high-voltage components can be designed as described herein.

[0017] It is preferred and advantageous that a charging current with a setpoint of 0 A is set while maintaining the charging process. In particular, such a charging current is set at the output of the charging device.

[0018] In an advantageous embodiment, at least one contactor is connected between the output of the charging device and the high-voltage vehicle electrical system. The contactor preferably comprises at least one contactor. In particular, the at least one contactor remains closed while the charging process is being maintained. The contactor enables, in particular, a (galvanic) isolation of the output of the charging device from the high-voltage vehicle electrical system.

[0019] Preferably, the contactor assembly comprises at least two contactors. In particular, at least one contactor, and preferably only one of the at least two contactors, remains closed while the charging process is maintained. In particular, at least one of the at least two contactors is open while the charging process is maintained. However, it is also possible that both contactors remain closed while the charging process is maintained.

[0020] In all embodiments, it is preferred that the input of the charging device remains connected to the AC power source while the charging process is maintained. In particular, an AC voltage is present at the input of the charging device while the charging process is maintained, and especially preferably throughout the entire charging process.

[0021] The motor vehicle according to the invention is suitable and designed to be operated according to the method according to the invention or one of its further developments. In particular, the motor vehicle comprises the components described within the framework of the method. In particular, the motor vehicle comprises at least one control unit for carrying out the method steps.

[0022] The motor vehicle includes, in particular, at least one control unit. The control unit is operatively connected to the battery system and / or the charging system and / or the high-voltage electrical system. The control unit is specifically suitable and configured to execute the steps of the procedure. In particular, the control unit can control the components operatively connected to it. The control unit includes, in particular, at least one algorithm for implementing the procedure steps described herein. The control unit can be integrated into the battery system (for example, as a battery management system) or the vehicle electronics.

[0023] Further advantages and features of the present invention will become apparent from the exemplary embodiments, which are explained below with reference to the accompanying figures.

[0024] The figure shows: Fig. 1 a purely schematic detailed representation of a motor vehicle according to the invention.

[0025] The Fig. Figure 1 shows a motor vehicle 1 that can be operated according to the method of the invention, of which only a section of the high-voltage system is shown here for clarity. The motor vehicle 1 is, for example, a battery-electric passenger car with a battery unit 2 designed as a high-voltage battery. The motor vehicle 1 also includes a high-voltage electrical system 4 with several high-voltage components 14, which is supplied with energy by the battery unit 2. The high-voltage components 14 are integrated into the high-voltage electrical system 4 in such a way that they can be switched on and off as needed.

[0026] Furthermore, the vehicle 1 includes a charging device 3 for charging the battery device 2 using alternating current from an external AC power source 33, for example, a wallbox. The charging device 3 has an input 13 for connecting to the AC power source 33. The charging device 3 is connected to the high-voltage electrical system 4 via an output 23.

[0027] One high-voltage component 14 is configured here as a drive unit 5, which includes at least one electric machine for a drive system. Another high-voltage component 14 is configured here as an electric chassis unit. The high-voltage electrical system 4 preferably includes further high-voltage components 14, of which only one is shown here as a dashed line, purely by way of example.

[0028] The vehicle 1 is equipped with a control unit 3, which allows high-voltage components 14 to be switched on during an ongoing AC charging process without interrupting the charging process. The switching on of a high-voltage component 14 is described in more detail below using the drive unit 5 as an example. Switching on the drive unit 5 during the charging process allows, for example, so-called drive heating to pre-condition the vehicle before driving.

[0029] During the charging process, output 23 is connected to the high-voltage electrical system 4, allowing a charging current (via the high-voltage electrical system 4) to flow into the battery unit 2. For this purpose, the two contactors 17 of a contactor unit 7, located between output 23 and the high-voltage electrical system 4, are closed.

[0030] When a request is made for drive heating, this is registered by the control unit 8. Subsequently, the high-voltage electrical system 4 is switched off to a de-energized state. For this purpose, the high-voltage electrical system 4 is galvanically isolated from the battery system 2. A contactor device (battery contactor), not shown in detail here, is provided for this isolation.

[0031] Meanwhile, the charging process continues. The AC voltage from the AC power source 33 remains present at input 13. For example, a target current of 0 A is specified. However, no power is transferred to the high-voltage electrical system 4 at output 23. At least one contactor 17, or even both contactors 17, remain closed.

[0032] The drive unit 5 is now connected to the high-voltage electrical system 4. Once the drive unit 5 has been successfully connected, the high-voltage electrical system 4 is restarted. The drive unit 5 can now be supplied with energy by the battery unit 2. The charging process continues, with the charging current now set to a value greater than zero.

Claims

[1] Method for operating a motor vehicle (1) that is at least partially electrically powered, comprising a battery device (2), a charging device (3) for charging the battery device (2) by means of alternating current from an external alternating current source (33) during a charging process, and a high-voltage electrical system (4) that can be supplied with electrical energy by the battery device (2) and has at least one high-voltage component (14), wherein the charging device (3) is connectable to the alternating current source (33) at an input (13) and is connected to the high-voltage electrical system (4) at an output (23), characterized by the following steps: - Making and / or registering a requirement for the operation of at least one high-voltage component (14) during the charging process; - Shutting down the high-voltage electrical system (4) to a voltage-free state in which the high-voltage electrical system (4) is disconnected from the battery system (2); - Maintaining the charging process so that an alternating voltage from the alternating current source (33) is present at the input (13) of the charging device (3) and no power transfer to the high-voltage on-board network (4) takes place at the output (23) of the charging device (3); - Switching the high-voltage component (14) to the high-voltage on-board network (4); - Starting up the high-voltage electrical system (4) so ​​that the connected high-voltage component (14) is supplied with energy by the battery system (2); - Continuation of the charging process with a transfer of power through the charging device (3) into the high-voltage on-board network (4). [2] Method according to the preceding claim, wherein a request for heating by means of the high-voltage component (14) is made and / or registered during the charging process. [3] Method according to the preceding claim, wherein the at least one high-voltage component (14) is designed as an electric drive device (5) and wherein the heating is carried out by a targeted current supply to the drive device (5). [4] Method according to one of the preceding claims, wherein the at least one high-voltage component (14) is designed as an electric chassis device (6) and wherein a request to actuate the electric chassis device (6) during the charging process is made and / or registered. [5] Method according to one of the preceding claims, wherein a charging current with a setpoint of 0 amperes is set while maintaining the charging process. [6] Method according to one of the preceding claims, wherein at least one contactor device (7) with at least one contactor (17) is connected between the output (23) of the charging device (3) and the high-voltage on-board network (4) and wherein the at least one contactor (17) remains closed while maintaining the charging process. [7] Method according to one of the preceding claims, wherein the input (13) of the charging device (3) remains connected to the AC power source (33) while maintaining the charging process. [8] Motor vehicle (1) for operation according to the method of any of the preceding claims.

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