Method for determining the condition of an external charging device and motor vehicle

Abstract

Method for determining the state of a vehicle-external charging device (3) for charging an electrical energy storage device (6) of a motor vehicle (2) with a charging port (8) to which a charging cable (9) of the charging device (3) is connected, wherein a temperature sensor (13) of the motor vehicle (2) detects a temperature in or on the charging port (8) during charging and a control device (14) of the motor vehicle (2) determines a quality information depending on temperature information describing the detected temperature, which describes the quality of at least one charging cable-side electrical contact (10) when it is contacted (12) on the charging port (8), characterized in that the determination of the quality information is additionally dependent on counter-contact information relating to the quality of at least one charging port-side counter-contact (11).

Description

[0001] The invention relates to a method for determining the state of an external charging device for charging an electrical energy storage device of a motor vehicle, having a charging port to which a charging cable of the charging device is connected. The invention also relates to a motor vehicle.

[0002] With the increasing capacity of energy storage devices in partially or fully electrically powered vehicles, the charging time of such an energy storage device is becoming increasingly important for the user-friendliness of the vehicle. It has been observed that for the same vehicle, charging times can vary considerably for comparable charging processes when connected to external charging devices of the same type. The charging time therefore depends on the technical condition of the charging device charging the vehicle's electrical energy storage device. The contact resistance at the contacts between the charging device-side charging cable and the vehicle-side charging connector plays a particularly important role, since the charging power decreases with increasing contact resistance.

[0003] EP 2 995 496 A1 discloses a charging device with a plug that supplies electrical energy to an electric vehicle via a plurality of plug contacts, and a plurality of temperature sensors arranged in the plug. A control unit determines whether the plug is overheating based on a temperature detected by the temperature sensors. If this temperature exceeds a threshold value, the charging intensity is reduced or charging is terminated.

[0004] Such a charging device therefore requires additional temperature sensors to be installed on the charging device. Furthermore, the technical condition of the charging device is only recorded in the charging device itself, making further processing of information describing this condition, particularly on the vehicle side, impossible for additional functions that improve user-friendliness.

[0005] DE 10 2010 022 140 A1 describes a connection device for an electric vehicle to which a charging cable from an external charging device can be connected. Various auxiliary devices, such as a temperature sensor, can be provided on the vehicle side. The temperature sensor measures a temperature signal that depends on the temperature in the area of ​​the plug connector and / or the temperature in the plug connector. The temperature signal measured by the temperature sensor is processed in a module and forwarded to an electronic vehicle control system, which detects whether there is a contact problem and / or excessive contact resistance within the connector.

[0006] DE 10 2009 034 886 A1 discloses a charging cable plug for connecting an electric vehicle to a charging station, which plug has a resistor for encoding the value of the current transmittable via the charging cable. Additionally, a temperature-dependent resistor can be provided, which can be arranged in the plug or in the motor vehicle. A charging current control device connected to the plug via a connection device can adjust the charging current via the total resistance resulting from the resistor used to encode the current and the temperature-dependent resistor. As temperatures rise and the resulting resistance change, a lower charging current is set.

[0007] WO 2015 / 169326 A1 discloses a method and arrangement for controlling the charging process of a motor vehicle-mounted energy storage device. The motor vehicle has a current collector with which contact can be made with an overhead line to charge the motor vehicle's energy storage device. A temperature sensor can be provided that measures the temperature of a contact point between the current collector and the overhead line, with a control device determining a power loss at the contact point from the temperature.

[0008] EP 2 995 496 A1 describes a charger comprising a plug which supplies an electric vehicle with electrical energy via a plurality of plug pins, a plurality of temperature sensors which are arranged in the plug and measure the temperatures of the plurality of plug pins, and a control unit which determines the presence or absence of overheating of the plug on the basis of the temperatures measured by the plurality of temperature sensors.

[0009] The invention is therefore based on the object of providing a possibility for determining the status of a vehicle-external charging device in a less complex and more user-friendly manner.

[0010] This object is achieved according to the invention in a method of the type mentioned at the outset in that a temperature sensor of the motor vehicle detects a temperature in or at the charging connection during charging and a control device of the motor vehicle determines quality information as a function of temperature information describing the detected temperature, which describes the quality of at least one electrical contact on the charging cable side when it makes contact with the charging connection, wherein the quality information is determined in additional dependence on mating contact information relating to the quality of at least one mating contact provided on the charging connection side.

[0011] The invention is based on the idea of ​​detecting heating of the charging port on the motor vehicle side and, based on the temperature information, determining quality information present in the motor vehicle, on the basis of which further user functions can be implemented. This heating results in particular from the total contact resistance of the contact between the charging cable contact and a corresponding mating contact on the charging port. The contact resistance of the charging cable contact increases with the number of plug-in cycles due to wear or aging. This leads to an increase in the temperature in the area of ​​the charging port during charging compared to an intact contact. Accordingly, the detected temperature is used as an indicator of the contact's transfer resistance, which simultaneously has a decisive influence on the performance of the charging process.The invention takes advantage of the fact that a large number of motor vehicles, particularly partially or fully electrically powered ones, already have a temperature sensor with one or more sensor elements in the area of ​​the charging port, also referred to as a charging socket. Based on the detection results of the temperature sensor, a conclusion can be drawn about the quality of at least one electrical contact of the charging cable, with the quality being represented by the quality information.

[0012] This eliminates the need for complex, additional temperature sensors within the charging device. This allows the quality information to be determined for a wide variety of charging devices, regardless of the vehicle's charging device configuration. Furthermore, the quality information is available on the vehicle side and can be further processed to improve the vehicle's user-friendliness.

[0013] Typically, within the scope of the method according to the invention, a charging device with a permanently installed charging cable is used, in particular one that cannot be removed by the user before, during, or after the charging process. The charging device preferably provides a direct voltage for charging the motor vehicle, although the method according to the invention is also generally applicable to charging the motor vehicle with single-phase or multi-phase alternating current. However, permanently installed charging cables are more common for charging with direct current. The charging device can be a freestanding charging device, typically publicly accessible, which is often also referred to as a charging station and is located in public spaces, for example, near parking lots. Alternatively, the charging device can be installed in a building. Such charging devices are typically not publicly accessible and are also referred to as wall chargers or wall boxes.

[0014] In the method according to the invention, it is preferred if the quality information is determined based on a deviation of the detected temperature from a predetermined reference value. This reference value is typically stored in the control device. Advantageously, the reference value describes a temperature that occurs when charging the energy storage device via an intact contact of a charging cable. A temperature described by the reference value, which occurs during charging via an unworn contact of the charging cable, can therefore serve as the basis for determining the quality information. For example, it is possible for the temperature to be obtained from a calibration measurement by the temperature sensor.Such a calibration measurement can, for example, initially be carried out using a standardized charging device, whereby the vehicle-side temperature sensor itself detects the temperature increase in or at the charging port that occurs during charging.

[0015] In order to account for the influence of the condition of the vehicle-side charging connector on the total contact resistance, the quality information is determined according to the invention in addition to mating contact information relating to the quality of at least one mating contact provided on the charging connector side. Since the total contact resistance is composed of the contact resistances of the charging cable-side contact and the mating contact of the charging connector, the quality information can be further refined by additionally considering the mating contact information. Thus, the aging or wear of the mating contacts of the charging connector is also incorporated into the determination of the quality information.

[0016] To determine the counter contact information, it can be provided that it describes a number of connection processes of the charging port in the past. Such modeling of the contact resistance of the counter contact based on the number of connection processes that have occurred enables particularly simple determination of the counter contact information, since only a counter needs to be incremented and stored on the control device side to record the number.

[0017] In the method according to the invention, it is further preferred if the control device, depending on the quality information, controls an output device of the motor vehicle to output a user message indicating the status of the charging device and / or the predicted duration of the charging process. The output can be optical, acoustic, or haptic, in particular. The output device can be, for example, an instrument cluster of the motor vehicle or a screen installed in the motor vehicle. Furthermore, a display device, for example a colored light, can be provided at the charging connection, which display device is controlled at least when quality information describing a quality below a predetermined threshold is present.When issuing the user information indicating the predicted duration of the charging process, it is further preferred if this duration is given taking into account the charging voltage and / or the charging current and / or the charging power.

[0018] Alternatively or additionally, the method according to the invention can advantageously provide for the quality information or information derived therefrom to be stored in a memory device on the motor vehicle and read out by a reading device external to the vehicle in order to output an indication indicating the status of the charging device. Such a memory device can, for example, be an error memory of the motor vehicle. The user of the motor vehicle can then be informed by a person using the reading device, for example workshop personnel during repair or maintenance of the motor vehicle, that a contact of a charging device in use is of only poor quality. This is particularly useful for charging devices installed on the building, for example the aforementioned wall box. The user of the motor vehicle orThe charging device can thus be encouraged to initiate a technical inspection of the charging device. In this context, it is preferable if, in addition to the quality information, identification information identifying the charging device is stored, so that it can be determined which of possibly several charging devices used in the past needs to be inspected.

[0019] Furthermore, the method according to the invention can provide for the quality information to be transmitted to a server external to the vehicle by means of a communication device on the vehicle. Such a server can, for example, be a backend that provides information to a plurality of motor vehicles, for example, within the framework of fleet management. Here, too, it is preferred if identification information identifying the charging device and / or position information describing the position of the charging device, for example based on geodetic coordinates, is additionally transmitted.

[0020] It is particularly preferred if the server transmits the quality information or information derived therefrom to another motor vehicle and / or a communication device, wherein the motor vehicle and / or the communication device, depending on the quality information or derived information, outputs an indication indicating the status of the charging device and / or selects a charging device to be used for another charging process. Such a communication device can be, for example, a portable telephone, in particular a smartphone, which has an internet connection that establishes a communication connection with the server.The server therefore distributes the quality information or the derived information to other motor vehicles and / or communication devices so that their users can be given an indication of the technical condition of charging facilities in their vicinity and / or an automated selection of a charging facility can be made based on its condition.

[0021] The object underlying the invention is further achieved according to the invention by a motor vehicle comprising an electrical energy storage device and a charging connection to which a charging cable of a charging device external to the motor vehicle can be connected for charging the energy storage device, a temperature sensor which is designed to detect a temperature at or in the charging connection, and a control device designed to carry out the method according to the invention.

[0022] All statements regarding the method according to the invention can be transferred analogously to the motor vehicle according to the invention, so that the aforementioned advantages can also be achieved with this.

[0023] Further advantages and details of the invention will become apparent from the exemplary embodiments described below and from the drawings. These are schematic representations and show: Fig. 1 shows a schematic diagram of an arrangement comprising a motor vehicle according to the invention, a vehicle-external charging device and a server; and Fig. 2 a flowchart of a method according to the invention.

[0024] Fig. Figure 1 shows a schematic diagram of an arrangement 1 comprising a motor vehicle 2, an off-board charging device 3, and an off-board server 4. The motor vehicle 2 has a drive device 5 for its partial or complete electric drive. An electrical energy storage device 6 is provided to supply the drive device 5 and is connected to a charging port 8 of the motor vehicle 2 via a charging control unit 7.

[0025] A charging cable 9, which is permanently installed on the charging device 3, is connected to the charging port 8, wherein contacts 10 of a plug-in connector of the charging cable 9 form a contact 12 with identically designed mating contacts 11 of the charging port 8 for charging the energy storage device 5. Furthermore, a temperature sensor 13 is provided in or on the charging port 8, which can, for example, be formed from a plurality of sensor elements distributed in the area of ​​the charging port 8. The contact 12 has a total contact resistance, which is made up of the respective contact resistances of the contacts 10 on the charging cable side and the mating contacts 11 on the charging port side. With increasing age and wear of the contacts 10 orof the mating contacts 11 through corresponding plug-in cycles, the respective contact resistances and accordingly also the total contact resistance increase, which leads to increased heating when charging the energy storage device 5, which can be detected by the temperature sensor 13.

[0026] The temperature sensor 13 is connected to a control device 14 of the motor vehicle 2, which is configured to carry out a method for determining a state of the vehicle-external charging device 3, which is explained in more detail below: Fig. 2 shows a flowchart of this method, which begins in a step S1 in which - as previously described - the charging cable 9 is connected to the charging port 8 and the energy storage device 5 is charged by the charging device 3.

[0027] In a step S2, the temperature sensor 13 detects a temperature in or at the charging port 8 and provides temperature information describing this temperature to the control device 14. In doing so, the temperature sensor 13 detects a temperature profile until it has assumed a substantially steady-state value for determining the temperature.

[0028] In a subsequent step S3, the control device 14 determines, depending on the temperature information and mating contact information retrieved from a storage unit 15, quality information which describes the quality of the electrical contacts 10 on the charging cable side when they make contact with the charging port 8. To do this, the control device 14 compares the temperature with a predetermined reference value. This is also stored in the storage unit 15 and can be obtained from an initial calibration measurement by the temperature sensor 13. As part of this calibration measurement, a standardized charging device with completely intact contacts on the charging cable side was connected to the charging port 8, and the highest possible heating generated was recorded as a reference value. The quality of the electrical contacts 10 is determined based on the deviation of the temperature described by the temperature information from the reference value.

[0029] To further specify this quality, the control device 14 retrieves the mating contact information from the memory unit 15, which describes a number of connection processes of the charging port 8 in the past. This number is used as a measure of the wear already incurred on the mating contacts 11, which also contribute to the overall contact resistance. With a high number of historical connection processes, the quality determined from the temperature is therefore adjusted downward, since the overall contact resistance is determined to a greater extent by the contact resistance of the mating contacts 11. The quality of the contacts 10 determined in this way by the control device 14 is represented by the quality information.

[0030] In a subsequent step S4, the control device 14 evaluates the quality information and, depending on this, controls an optical and / or acoustic and / or haptic output device 16 (cf. Fig. 1) to display a user message indicating the status of the charging device and the predicted duration of the charging process. For example, if the quality information indicates poor quality, the message "This charging station is not performing well - To optimize the charging time, please use another charging station if possible" can be displayed on the vehicle's instrument cluster. Alternatively, the quality of the contact 12 can be symbolized by a colored light (not shown) arranged in the area of ​​the charging port 8 as an output device 16.

[0031] Alternatively or in addition to step S4, the steps S5, S6 described below can be carried out as part of the method: In step S5, the control device 14 stores the quality information together with identification information identifying the charging device 3 in the memory unit 15, which is additionally designed as an error memory.

[0032] In the subsequent step S6—at a time after the motor vehicle has been charged—the storage unit 15 is read by a vehicle-external reading device (not shown), for example, during a workshop visit for maintenance or repair. A message is output on the reading device indicating whether quality information indicating poor quality has been determined for a regularly used charging device. Since such a regularly used charging device is often permanently integrated into a building belonging to the user of the motor vehicle 1, for example, for charging the energy storage device 6 overnight, the personnel operating the reading device can issue a message indicating that this charging device requires technical inspection.

[0033] Again alternatively or in addition to steps S4 and / or S5, S6, the following steps S7, S8 are carried out: In step S7, the control device 14 controls a communication device 17 that implements an Internet connection (cf. Fig. 1) for transmitting the quality information, the identification information and position information describing the position of the loading device 3 in geodetic coordinates to the server 4.

[0034] Subsequently, in step S8, the server 4 evaluates this information along with further similar information transmitted by other motor vehicles regarding other charging devices. The information derived therefrom is at least partially transmitted to a communication device (not shown), e.g., a smartphone, so that other users can be provided with a notification indicating the status of the charging device 3. Users can therefore assess the quality of the charging devices located nearby. Alternatively or additionally, the communication device can also independently select the most suitable charging station in the area. Alternatively or additionally to the transmission from the server 4 to the communication device, a corresponding transmission can also be made to the motor vehicle 2 or another motor vehicle.

Claims

[1] Method for determining a state of a vehicle-external charging device (3) for charging an electrical energy storage device (6) of a motor vehicle (2) having a charging connection (8) to which a charging cable (9) of the charging device (3) is connected, wherein a temperature sensor (13) of the motor vehicle (2) detects a temperature in or at the charging connection (8) during charging and a control device (14) of the motor vehicle (2) determines, as a function of temperature information describing the detected temperature, quality information which describes the quality of at least one electrical contact (10) on the charging cable side when it is contacted (12) at the charging connection (8), characterized by that the quality information is determined in additional dependence on counter-contact information relating to the quality of at least one counter-contact (11) provided on the charging connection side. [2] Method according to claim 1, characterized bythat the quality information is determined based on a deviation of the recorded temperature from a specified reference value. [3] Method according to claim 2, characterized by that the reference value describes a temperature, in particular obtained from a calibration measurement by the temperature sensor (13), which occurs when charging the energy storage device (6) via an intact contact of a charging cable. [4] Method according to claim 3, characterized by that the counter contact information describes a number of connection processes of the charging connection (8) in the past. [5] Method according to one of the preceding claims, characterized by that the control device (14), depending on the quality information, controls an output device (16) of the motor vehicle (2) to output a user instruction indicating the state of the charging device (3) and / or the predicted duration of the charging process. [6] Method according to one of the preceding claims, characterized by that the quality information is stored in a motor vehicle-side storage device (15) and read out by a motor vehicle-external reading device to output an indication indicating the status of the charging device (3). [7] Method according to one of the preceding claims, characterized by that the quality information is transmitted to a server (4) external to the vehicle by means of a motor vehicle-side communication device (17). [8] Method according to claim 7, characterized bythat the server transmits the quality information or information derived therefrom to another motor vehicle and / or a communication device, wherein the motor vehicle and / or the communication device, depending on the quality information or derived information, issues an indication indicating the status of the charging device and / or selects a charging device to be used for another charging process. [9] Motor vehicle, comprising an electrical energy storage device (6) and a charging connection (8) to which a charging cable (9) of a charging device (3) external to the motor vehicle can be connected for charging the energy storage device (6), a temperature sensor (13) which is designed to detect a temperature at or in the charging connection (8), and a control device (14) designed to carry out a method according to one of the preceding claims.

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