vehicle

Abstract

The invention relates to a vehicle (1). According to the invention, the vehicle (1) comprises: - a high-voltage system with a high-voltage battery, - a low-voltage system without a low-voltage battery, which can be supplied by electrical energy from the high-voltage battery, and - a low-voltage connection (4) for connecting a vehicle-external low-voltage energy source for supplying electrical energy to the low-voltage system, which is arranged in a vehicle compartment (6) closed by means of an emergency-releaseable locking element (5) and is accessible from the outside after the emergency release of the locking element (5). Furthermore, the invention relates to a method for starting a charging process for charging the discharged high-voltage battery of the vehicle (1).

Description

[0001] The invention relates to a vehicle according to the features of the preamble of claim 1 and a method for starting a charging process for charging a discharged high-voltage battery of the vehicle.

[0002] A portable device for jump-starting a vehicle engine is known from the prior art, as described in DE 10 2014 114 997 A1. The device comprises a rechargeable lithium-ion battery unit and a microcontroller. The lithium-ion battery is coupled via a FET smart switch to a current output interface of the device, which is operated by the microcontroller. A vehicle battery isolation sensor, connected to positive and negative polarity outputs in a circuit, detects the presence of a vehicle battery connected between the positive and negative polarity outputs.A reverse polarity sensor connected to the positive and negative polarity outputs in a circuit detects the polarity of a vehicle battery connected between the positive and negative charged outputs, allowing the microcontroller to supply voltage from the lithium-ion power unit to the output terminal only when a functioning battery is connected to the output terminal and only when the battery is connected with the correct polarity to the positive and negative terminals.

[0003] DE 10 2018 222 741 A1 describes a method and a device for charging a low-voltage battery in a vehicle's electrical system. Charging is performed by a generator using a DC / DC converter. The charging capacity of the low-voltage battery is divided into three capacity segments. The current state of charge of the low-voltage battery is determined. It is determined in which of the three capacity segments the current state of charge lies. The low-voltage battery is charged depending on the determined capacity segment.

[0004] DE 10 2016 109 337 A1 discloses a method and a system for controlling the charging of a low-voltage battery of a vehicle. The method comprises determining a state of charge of the low-voltage battery based on a voltage of the low-voltage battery and determining a state of charge of the low-voltage battery based on an amount of power consumed by a low-voltage direct-current (OC) converter that provides charging power to the low-voltage battery during a period in which a vehicle start-up is performed. A charging voltage for the low-voltage battery is then set based on a determination result of the state of charge of the low-voltage battery.

[0005] DE 10 2014 006 746 A1 discloses a device and method for providing electrical energy through a plurality of rechargeable battery cells, which can also be contacted at least individually. To avoid different charge levels among the battery cells, the respective charge level is measured, and depending on this, those modules with a high or highest charge level are connected to another electrical load. Conversely, individual battery cells can also be charged via an on-board electrical system and DC / DC converters.

[0006] The disclosure of DE 10 2021 132 972 A1 discloses a manually unlockable loading flap device of a motor vehicle, the loading flap of which is connected to a locking and unlocking unit which can be actuated by a power transmission means from a towing eye access.

[0007] DE 10 2021 200 323 A1, on the other hand, describes a charging connection with a plug-in device, wherein the connection cable between the charging connection and an energy storage device has another cable as an additional cable with a connection, so that the energy storage device can also be coupled via the additional cable with an additional connection.

[0008] DE 10 2021 111 450 A1 discloses a device for emergency power supply of a motor vehicle, by which an internal electrical power source can be supplied with external electrical power. For this purpose, at least one supply cable to the internal power source is arranged behind a cover device for closing a body-side opening.

[0009] The invention is based on the object of specifying a vehicle that is improved compared to the prior art and a method that is improved compared to the prior art for starting a charging process for charging a discharged high-voltage battery of the vehicle.

[0010] The object is achieved according to the invention by a vehicle having the features of claim 1 and a method for starting a charging process for charging a discharged high-voltage battery of the vehicle having the features of claim 5.

[0011] Advantageous embodiments of the invention are the subject of the subclaims.

[0012] According to the invention, a vehicle has a high-voltage system with a high-voltage battery. The vehicle is designed, in particular, as an electrically powered vehicle. It thus has at least one electric drive motor for driving the vehicle, which can be supplied with electrical energy by means of the high-voltage battery.

[0013] According to the invention, the vehicle further comprises a low-voltage system which can be supplied with electrical energy from the high-voltage battery and at least temporarily has no energy supply from a low-voltage battery. This can be the case if no low-voltage battery is present or provided in the vehicle or if the low-voltage battery is completely discharged and can no longer provide energy, so that energy supply from the low-voltage battery is not possible due to its charge state. A low-voltage battery for supplying the low-voltage system can basically be dispensed with if the low-voltage system can be supplied with energy from the high-voltage battery. A low-voltage battery, which is not present in the vehicle according to the invention or, if present, can be completely discharged, is understood in particular to be a rechargeable low-voltage on-board network battery.Such low-voltage on-board power supply batteries are provided in other vehicles to supply electrical power to components of the low-voltage system. Since the vehicle according to the invention has no low-voltage battery or no charged low-voltage battery, the electrical power supply to the low-voltage system is provided by the high-voltage battery, in particular via a DC-DC converter, by means of which a voltage of the high-voltage battery can be converted into a lower voltage of the low-voltage system.

[0014] A particular problem with this vehicle design is that a low-voltage electrical energy supply for the vehicle's control units, which are active in the vehicle's idle mode, must be ensured via the high-voltage battery. This applies, for example, to control units for communication or for opening the vehicle, but in particular to one or more control units that are required to carry out a charging process for the high-voltage battery from a high-voltage energy source external to the vehicle. If the high-voltage battery is completely or very heavily discharged, i.e.at least so heavily discharged that the low-voltage system, in particular the control unit or control units required to carry out the charging process, can no longer be supplied with the electrical energy required to carry out the charging process by the high-voltage battery, then the vehicle can no longer be opened and activated in the normal way and in particular it is then no longer possible to start the charging process because, in order to start the charging process, the necessary steps, in particular safety checks, must first be carried out by means of the control unit or control units and then the charging switches, in particular charging contactors, must be closed. Such a very heavily discharged state of the high-voltage battery can occur, for example, if the vehicle has been parked for a very long time, in particular after it has been parked with a very low state of charge of the high-voltage battery.

[0015] In particular, to solve this problem, the invention provides that the vehicle has a low-voltage connection for connecting a vehicle-external low-voltage energy source for supplying electrical energy to the low-voltage system, in particular to the at least one control unit or the plurality of control units required to carry out the charging process for charging the high-voltage battery from a vehicle-external high-voltage energy source. According to the invention, this low-voltage connection is arranged in a vehicle compartment of the vehicle that is closed by means of an emergency-releasable locking element and is accessible from the outside, i.e., from outside the vehicle, after the locking element has been emergency released.

[0016] In a method according to the invention for starting the charging process for charging the discharged high-voltage battery of the vehicle from a high-voltage energy source external to the vehicle, i.e. for starting the charging process in particular when the high-voltage battery is discharged, in particular completely discharged or at least so heavily discharged that the low-voltage system cannot be supplied with the electrical energy required to carry out the charging process by the high-voltage battery, the closure element is emergency unlocked, a low-voltage energy source external to the vehicle, for example a so-called power bank, is connected to the low-voltage connection and the low-voltage system or the at least one control unit required to carry out the charging process or the several control units of the low-voltage system required to carry out the charging process are supplied with electrical energy by the low-voltage energy source external to the vehicle.All necessary steps to start the charging process are carried out, in particular automatically, and the charging process is started, i.e. in particular safety checks are carried out and then the charging switches, in particular charging contactors, are closed.

[0017] In one embodiment, the low-voltage connection is protected from environmental influences, in particular against weather influences, dirt, moisture and / or liquid, by the closure element and / or by a protective cover.

[0018] In a first embodiment of the invention, the vehicle compartment of the vehicle in which the low-voltage connection is arranged is, for example, a charging recess of the vehicle. It is provided in particular that a charging connection for charging the high-voltage battery from a high-voltage energy source external to the vehicle is also arranged in this charging recess. The closure element is then in particular a charging flap for closing the charging recess, in particular from an external environment of the vehicle. After emergency unlocking of the closure element, i.e. the charging flap, both the low-voltage connection and the charging connection are thus accessible from the outside, i.e. from outside the vehicle. In this embodiment, the charging process for charging the high-voltage battery from the high-voltage energy source external to the vehicle can therefore be started without access to a vehicle interior, in particular the passenger compartment or trunk.

[0019] In a second embodiment of the invention, the vehicle compartment of the vehicle in which the low-voltage connection is arranged is, for example, a passenger compartment or trunk or another compartment, in particular the interior, of the vehicle, wherein the closure element is then, in particular, a vehicle door or trunk lid or another lid. After the emergency unlocking of this closure element, only the low-voltage connection is accessible from outside the vehicle, for example. In this embodiment, the charging flap closing the charging recess with the charging connection is unlocked, for example, only after the electrical power supply to the low-voltage system or at least to the at least one control unit or units required to carry out the charging process has been established by means of the vehicle-external low-voltage power source connected to the low-voltage connection in the manner described above.

[0020] It goes without saying that the charging process for the high-voltage battery in the method described above only starts after an external high-voltage energy source has been connected to the vehicle's charging port. In the first variant of the vehicle compartment being designed as a charging recess, in which both the low-voltage connection and the charging connection for the high-voltage energy source are located, this can thus occur, for example, directly after the emergency release of the locking element designed as a charging flap, in particular directly before or after the connection of the external low-voltage energy source to the low-voltage connection.In the second variant, in which the locking element is not the charging flap, this connection of the vehicle-external high-voltage energy source to the vehicle's charging port can, for example, only take place after the charging flap can be unlocked in the manner described above by the electrical energy supply using the vehicle-external low-voltage energy source.

[0021] For example, an emergency release mechanism for emergency release of the locking element can have a lock that is accessible from the outside and can be mechanically operated by means of a key.

[0022] For example, the emergency release mechanism for emergency release of the locking element can have an unlocking unit coupled to an externally accessible manual actuating element for moving the unlocking unit into an unlocking position. This actuating element is designed, for example, as a Bowden cable, pulling element, pressure element, pivoting element, or rotary element. The actuating element is arranged on the vehicle in a particularly concealed and thus particularly hidden manner, i.e., not visible, or at least not immediately visible, particularly when viewed from the outside. For example, the actuating element is arranged in a wheel arch of the vehicle.

[0023] According to the invention, if the charge level of the high-voltage battery falls below a predetermined minimum value, the locking element is automatically released by means of electrical energy from the high-voltage battery. The emergency release is thus carried out by means of an electrical emergency release unit which is supplied with electrical energy from the high-voltage battery. Since this would no longer be possible with a discharged high-voltage battery, the charge level of the high-voltage battery is monitored, and if the charge level falls below the predetermined minimum value, the emergency release is carried out. This minimum value is predetermined in such a way that it is ensured that if the charge level falls below this minimum value, in particular immediately if it is fallen below this minimum value, the high-voltage battery can still provide the emergency release unit with sufficient electrical energy to carry out the emergency release.

[0024] In this embodiment, the method described above provides in particular that the emergency release is carried out automatically by means of electrical energy from the high-voltage battery as soon as the predetermined minimum value of the charge state of the high-voltage battery is undershot.

[0025] In one embodiment, the low-voltage connection is bidirectional. In addition to the above-described electrical power supply to the vehicle's low-voltage system by means of a low-voltage energy source external to the vehicle, this embodiment also enables, for example, a connection of a low-voltage consumer external to the vehicle to the low-voltage connection and thus its electrical power supply via the vehicle, in particular via the high-voltage battery and the vehicle's low-voltage system, particularly when the high-voltage battery is fully or at least partially charged.

[0026] In one embodiment, the low-voltage connection is designed as a USB-C connector (USB = Universal Serial Bus). The USB-C connector is, for example, a USB-C socket. Alternatively, the counterpart, i.e., a USB-C plug, can also be used as the USB-C connector.

[0027] The described solution enables the charging process to be started via the low-voltage connection located on the vehicle, e.g., a USB-C socket. Access to the low-voltage connection is achieved via the emergency release of the locking element, for example, using the key to operate the lock or by manually operating the actuating element, or by automatically executing the emergency release before the high-voltage battery fails, i.e., when the high-voltage battery's charge level falls below the specified minimum value.

[0028] The vehicle has, in particular, a low-voltage connection control unit, in particular a bidirectional low-voltage connection control unit. When the low-voltage connection is configured as a USB-C connection, this low-voltage connection control unit is a, in particular bidirectional, USB-C control unit. This low-voltage connection control unit controls, in particular, the electrical energy supply of the low-voltage system, in particular of the at least one control unit or the plurality of control units required to carry out the charging process for charging the high-voltage battery from a vehicle-external high-voltage energy source, after the low-voltage energy source has been connected to the low-voltage connection of the vehicle, i.e.The control unit or control units required to start the charging process can be supplied with electrical energy in this way by the low-voltage connection control unit, in particular the USB-C control unit, which is in particular bidirectional.

[0029] It is particularly provided that during the electrical energy supply to the at least one control unit or the plurality of control units required to carry out the charging process for charging the high-voltage battery from a high-voltage energy source external to the vehicle, all other low-voltage consumers of the vehicle are or are switched off by means of the vehicle-external low-voltage energy source connected to the low-voltage connection, i.e. are not supplied with electrical energy by the vehicle-external low-voltage energy source. This prevents overloading of the vehicle-external low-voltage energy source. As a result, a particularly transportable, i.e. particularly small and lightweight, vehicle-external low-voltage energy source, for example a power bank, is sufficient to start the charging process of the high-voltage battery in the manner described above.

[0030] The described solution thus enables, in particular, an emergency power supply for the vehicle's low-voltage system, so that, in a vehicle that has no low-voltage battery or one that is not charged with energy, the vehicle can be activated even when the high-voltage battery is completely discharged, in particular to perform a system check and / or required safety checks and to close the charging switches, in particular charging contactors, and to start charging the high-voltage battery from a high-voltage energy source external to the vehicle. For this emergency power supply, the externally accessible low-voltage connection is used, which is located, for example, in the charging recess and is accessible via the emergency release of the charging flap.The low-voltage connection can be designed as a simple USB-C connection, which is either designed only to supply electrical energy to the low-voltage system from the outside or can be designed bidirectionally and is therefore also available as a normal USB connection on the outside of the vehicle in order to be able to supply low-voltage energy consumers outside the vehicle with electrical energy.

[0031] As described above, the low-voltage connection is particularly weatherproof. It is particularly important that the low-voltage connection is accessible from the outside after the emergency release. Furthermore, the design of this emergency release is particularly designed to protect the low-voltage connection, at least as far as possible, from unauthorized access. This can be achieved, for example, by the automatic emergency release described above, which only occurs when the high-voltage battery's charge level falls below the specified minimum, or by the lock described above, which can only be opened with a key, or by the concealed actuating element described above.

[0032] In the method described above, it is particularly provided that the locking element is emergency unlocked and the vehicle-external low-voltage energy source, for example a power bank, is connected to the low-voltage connection, which is designed in particular as a USB-C port. The low-voltage connection control unit, in particular a USB-C control unit, which is designed in particular as a bidirectional connection, is thereby supplied with energy. This low-voltage connection control unit can supply the control units required to start the charging process. All other low-voltage consumers are disconnected. This means that the at least one control unit required to carry out the charging process or the several control units of the low-voltage system required to carry out the charging process are / are supplied with electrical energy by the vehicle-external low-voltage energy source.

[0033] If the emergency-released locking element is not the charging flap, the charging flap is now unlocked to allow connection of an external high-voltage energy source (DC or AC), in particular a high-voltage charging cable connected to it, to the vehicle's charging port. If the charging flap is the locking element, it is already emergency-released and the charging port is accessible.

[0034] The vehicle-external high-voltage energy source, in particular the high-voltage charging cable connected to it, is now connected to the vehicle's charging port, in particular plugged into it.

[0035] All necessary steps to start the charging process are carried out, in particular automatically, and the charging process is started. This means that, in particular, safety checks are carried out, for example, insulation monitoring or interlock testing, and a charging protocol is created in accordance with specified standards, in particular by the control units and components involved in the vehicle. The charging switches, in particular charging contactors, are closed. For example, high-voltage pre-charging, for example for the charging path, is also carried out via this low-voltage energy supply using the vehicle-external low-voltage energy source. The charging process for charging the high-voltage battery at the vehicle-external high-voltage energy source is started, and energy is stored in the high-voltage battery.The regular low-voltage energy supply of the vehicle's low-voltage system by the high-voltage battery and / or the vehicle-external high-voltage energy source with which the high-voltage battery is charged is now taken up via the DC-DC converter and the low-voltage energy supply via the vehicle-external low-voltage energy source is deactivated.

[0036] Embodiments of the invention are explained in more detail below with reference to drawings.

[0037] Showing: Fig. 1 schematically shows an embodiment of a vehicle, Fig. 2 schematically shows another embodiment of the vehicle, and Fig. 3 schematically shows a loading trough of the vehicle.

[0038] Corresponding parts are provided with the same reference numerals in all figures.

[0039] The Fig. 1 and Fig. 2 show two exemplary embodiments of a vehicle 1. Fig. 3 shows an example of a loading trough 2 of the vehicle 1, which is in the Fig. 1 and Fig. 2 is closed by means of a loading flap 3.

[0040] The vehicle 1 has a high-voltage system with a high-voltage battery. The vehicle 1 is designed, in particular, as an electrically powered vehicle 1. It thus has at least one electric drive motor for driving the vehicle 1, which can be supplied with electrical energy by means of the high-voltage battery.

[0041] The vehicle 1 further comprises a low-voltage system without a low-voltage battery, which can be supplied by means of electrical energy from the high-voltage battery, in particular via a DC-DC converter.

[0042] A particular problem with this embodiment of vehicle 1 without a low-voltage battery is that a low-voltage electrical energy supply for control units of vehicle 1 that are active when vehicle 1 is in sleep mode must be ensured via the high-voltage battery. This applies, for example, to control units for communication or for opening vehicle 1, but in particular to control units that are required to carry out a charging process for charging the high-voltage battery using a high-voltage energy source external to the vehicle. If the high-voltage battery is discharged, vehicle 1 can no longer be opened and activated in the normal way and, in particular, starting the charging process is then no longer possible. This is because, for example, starting the charging process requires the necessary steps, in particular safety checks, to first be carried out by means of the control units and then the charging contactors must be closed.Such a discharged state of the high-voltage battery can occur, for example, if the vehicle 1 is parked for a very long time, in particular after it has been parked with a very low state of charge of the high-voltage battery.

[0043] In particular, to solve this problem, the vehicle 1 is provided with a low-voltage connection 4 for connecting a vehicle-external low-voltage energy source for supplying electrical energy to the low-voltage system, in particular to the control units required to carry out the charging process for charging the high-voltage battery from a vehicle-external high-voltage energy source. This low-voltage connection 4 is arranged in a vehicle compartment 6 of the vehicle 1, which is closed by means of an emergency-releaseable locking element 5 and is accessible from the outside after the locking element 5 has been emergency released.

[0044] The low-voltage connection 4 is advantageously protected from environmental influences, in particular against weather influences, dirt, moisture and / or liquid, by the closure element 5 and / or by a protective cover.

[0045] In the illustrated embodiments, the vehicle compartment 6 of the vehicle 1, in which the low-voltage connection 4 is arranged, is the above-mentioned charging recess 2 of the vehicle 1, in which a charging connection 7 for charging the high-voltage battery is also arranged. In the illustrated embodiments, the closure element 5 is thus the charging flap 3 for closing the charging recess 2. After the emergency release of the closure element 5, i.e. the charging flap 3, both the low-voltage connection 4 and the charging connection 7 are accessible from the outside. In this embodiment, the charging process for charging the high-voltage battery can therefore be started at the high-voltage energy source external to the vehicle without access to the vehicle interior.

[0046] In a further embodiment not shown, the vehicle compartment 6 of the vehicle 1, in which the low-voltage connection 4 is arranged, is, for example, an interior space, in particular the passenger compartment, of the vehicle 1, wherein the closure element 5 is then, in particular, a vehicle door or flap. After the emergency unlocking of this closure element 5, only the low-voltage connection 4 is accessible from outside the vehicle 1, for example. In this embodiment, the charging flap 3 closing the charging recess 2 with the charging connection 7 is unlocked, for example, only after the electrical energy supply to the low-voltage system or at least to the control devices required to carry out the charging process has been established by means of the vehicle-external low-voltage energy source connected to the low-voltage connection 4.

[0047] In an embodiment not shown, an emergency release mechanism for emergency release of the closure element 5 has a lock that is accessible from the outside and can be mechanically actuated by means of a key.

[0048] In the embodiment according to Fig. 1, the emergency release mechanism for emergency release of the locking element 5 comprises an unlocking unit which is coupled to an externally accessible manual actuating element 8 for moving the unlocking unit into an unlocking position. This actuating element 8 is designed, for example, as a Bowden cable. The actuating element 8 is in particular concealed and thus in particular hidden, ie, in particular not visible from the outside during a normal view of the vehicle 1, or at least not immediately visible, arranged on the vehicle 1. For example, the actuating element 8, as shown in Fig. 1 schematically indicated, arranged in a wheel housing of the vehicle 1. In Fig. In Figure 1, the wheel housing or a fender of the vehicle 1 is shown transparently in the area of ​​the actuating element 8, so that the actuating element 8 and its arrangement and path are clearly visible. In reality, the actuating element 8 is concealed by the opaque fender, as it is located in the wheel housing.

[0049] In the embodiment according to Fig. 2, it is provided that if the charge level of the high-voltage battery falls below a predetermined minimum value, the emergency release of the locking element 5 is automatically carried out using electrical energy from the high-voltage battery. The emergency release is thus carried out by means of an electrical emergency release unit which is supplied with electrical energy from the high-voltage battery. Since this would no longer be possible with a discharged high-voltage battery, the charge level of the high-voltage battery is monitored, and if the charge level falls below the predetermined minimum value, the emergency release is carried out. This minimum value is predetermined in such a way that it is ensured that if the charge level falls below this minimum value, in particular immediately if it is fallen below this minimum value, the high-voltage battery can still provide the emergency release unit with sufficient electrical energy to carry out the emergency release.In this embodiment, no manual actuating element 8, for example a Bowden cable, is required for the emergency release.

[0050] In one embodiment, the low-voltage connection 4 is bidirectional. In addition to the above-described electrical power supply to the low-voltage system of the vehicle 1 by means of a vehicle-external low-voltage energy source, this embodiment also enables, for example, a connection of a vehicle-external low-voltage consumer to the low-voltage connection 4 and thus its electrical power supply via the vehicle 1, in particular via the high-voltage battery and the low-voltage system of the vehicle 1, particularly when the high-voltage battery is fully or at least partially charged.

[0051] In the illustrated embodiments, the low-voltage connection 4 is designed as a USB-C connection 9, in particular as a USB-C socket. In the described solution, the charging process can be started via the low-voltage connection 4 located on the vehicle 1 and designed, for example, as a USB-C socket. Access to the low-voltage connection 4 is achieved via the emergency release of the locking element 5, for example, by means of the key for operating the lock or, in the embodiment according to Fig. 1, by manually actuating the actuating element 8, or, in the embodiment according to Fig. 2, by automatically carrying out the emergency release before the high-voltage battery fails, ie when the charge level of the high-voltage battery falls below the specified minimum value.

[0052] The vehicle 1 has, in particular, a low-voltage connection control unit, in particular a bidirectional low-voltage connection control unit. When the low-voltage connection 4 is configured as a USB-C port 9, this low-voltage connection control unit is a USB-C control unit, in particular a bidirectional one.

[0053] This low-voltage connection control unit controls in particular the electrical energy supply of the low-voltage system, in particular the control units required to carry out the charging process for charging the high-voltage battery from a high-voltage energy source external to the vehicle, after the connection of the low-voltage energy source to the low-voltage connection 4 of the vehicle 1, ie these control units required to start the charging process can in this way be supplied with electrical energy by the low-voltage connection control unit, in particular the USB-C control unit, which is in particular designed bidirectionally.

[0054] In particular, it is provided that during the electrical energy supply of the control units required to carry out the charging process for charging the high-voltage battery from a vehicle-external high-voltage energy source, all other low-voltage consumers of the vehicle 1 are switched off by means of the vehicle-external low-voltage energy source connected to the low-voltage connection 4.

[0055] The described solution thus enables, in particular, an emergency power supply for the low-voltage system of vehicle 1, so that, in the case of vehicle 1, which does not have a low-voltage battery, activation of vehicle 1 is possible even when the high-voltage battery is completely discharged, in particular to perform a system check and / or required safety checks and to close the charging contactors and start charging of the high-voltage battery from a high-voltage energy source external to the vehicle. For this emergency power supply, the externally accessible low-voltage connection 4 is used. In the examples shown, this connection is arranged in the charging recess 2 and is accessible via the emergency release of the charging flap 3.In the examples shown, the low-voltage connection 4 is designed as a simple USB-C connection 9, which is either designed only to supply electrical energy to the low-voltage system from the outside or is also designed bidirectionally and is therefore also available as a normal USB connection on the outside of the vehicle 1 in order to be able to supply low-voltage energy consumers external to the vehicle with electrical energy.

[0056] As described above, the low-voltage connection 4 is particularly weatherproof and accessible from the outside after the emergency release. Furthermore, the design of this emergency release is particularly such that the low-voltage connection 4 is protected, at least as far as possible, from unauthorized access.

[0057] In a method for starting the charging process for charging the discharged high-voltage battery of the vehicle 1 from a high-voltage energy source external to the vehicle, it is provided in particular that the locking element 5 is emergency unlocked and the vehicle-external low-voltage energy source, for example a power bank, is connected to the low-voltage connection 4, which is designed in particular as a USB-C connection 9. The low-voltage connection control unit, in particular a USB-C control unit, which is designed in particular as a bidirectional connection, is thereby supplied with energy. This low-voltage connection control unit can supply the control units required to start the charging process. All other low-voltage consumers are disconnected. This means that the control units of the low-voltage system required to carry out the charging process are supplied with electrical energy by the vehicle-external low-voltage energy source.

[0058] If the emergency-released closure element 5 is not the charging flap 3, the charging flap 3 is now unlocked in order to be able to connect a vehicle-external high-voltage energy source, in particular a high-voltage charging cable connected thereto, to the charging connection 7 of the vehicle 1. If the charging flap 3 is the closure element 5, as in the embodiments according to the Fig. 1 to 3, it is already emergency unlocked and the charging port 7 is already accessible.

[0059] The vehicle-external high-voltage energy source, in particular the high-voltage charging cable connected to it, is now connected to the charging port 7 of the vehicle 1, in particular plugged into it.

[0060] All necessary steps to start the charging process are performed, and the charging process is started. This means that safety checks, such as insulation monitoring or interlock checks, are performed, particularly by the relevant control units and components in vehicle 1. A charging protocol is created according to specified standards. The charging contactors are closed. For example, high-voltage pre-charging, for example for the charging path, is also performed via this low-voltage energy supply using the vehicle-external low-voltage energy source. The charging process for charging the high-voltage battery at the vehicle-external high-voltage energy source is started, and energy is stored in the high-voltage battery.The regular low-voltage energy supply of the low-voltage system of the vehicle 1 by the high-voltage battery and / or the vehicle-external high-voltage energy source with which the high-voltage battery is charged is now taken up via the DC-DC converter and the low-voltage energy supply via the vehicle-external low-voltage energy source is deactivated. List of reference symbols 1 vehicle 2 loading trough 3 tailgate 4 Low-voltage connection 5 locking element 6 Vehicle compartment 7 Charging port 8 Actuating element 9 USB-C port

Claims

[1] vehicle (1), comprising - a high-voltage system with a high-voltage battery, - a low-voltage system without a power supply from a low-voltage battery, which can be supplied by electrical energy from the high-voltage battery, and - a low-voltage connection (4) for connecting an external low-voltage power source to supply electrical power to the low-voltage system, characterized by , that the low-voltage connection (4) is arranged in a vehicle compartment (6) closed by means of an emergency release locking element (5) and, if a predetermined minimum value of the charge level of the high-voltage battery is undershot, an automatic emergency release of the locking element (5) is provided by means of electrical energy from the high-voltage battery, so that after the emergency release of the locking element (5) the compartment is accessible from the outside, wherein the enclosed vehicle compartment (6) - a charging recess (2) in which a charging port (7) for charging the high-voltage battery is further arranged, wherein the closing element (5) is a charging flap (3) for closing the charging recess (2), or - a passenger compartment or trunk, wherein the locking element (5) is a vehicle door or trunk lid. [2] Vehicle (1) according to claim 1, characterized by , that the low-voltage connection (4) is protected from environmental influences by the locking element (5) and / or by a protective cover. [3] Vehicle (1) according to claim 1 or 2, characterized by , that the low-voltage connection (4) is bidirectional. [4] Vehicle (1) according to any of the preceding claims, characterized by , that the low-voltage connection (4) is designed as a USB-C connection (9). [5] Method for starting a charging process to charge the discharged high-voltage battery of the vehicle (1) at an external high-voltage energy source according to one of the preceding claims, wherein - the locking element (5) is automatically unlocked by means of electrical energy from the high-voltage battery if the specified minimum value of the charge level of the high-voltage battery is undershot, - an external low-voltage power source is connected to the low-voltage connection (4), - the low-voltage system or at least one control unit of the low-voltage system required to carry out the charging process at an external high-voltage energy source is supplied with electrical energy by the vehicle's external low-voltage energy source, - all necessary steps to start the charging process of the high-voltage battery at an external high-voltage power source are carried out, and - the charging process of the high-voltage battery is started at an external high-voltage energy source.

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