Method and device for charging an electrically driven vehicle

Abstract

The invention relates to a method for charging an electrically driven vehicle (110), wherein, based on the resistance (R A , R B ) of at least one interface component (102, 104) of an interface (100) between a charging device (108) and the vehicle (110), which has been ascertained during at least one previous charging process, a maximum charging current (I MAX ) of the charging process (200) is pre-determined before the charging process (200) for charging the vehicle (110).

Description

Technical Field

[0001] The present invention relates to a method and a corresponding device for charging an electrically driven vehicle. Background Art

[0002] In order to quickly charge the traction battery of an electrically driven vehicle, a large electrical charging power is required. Since the voltage of the traction battery is specified, a high electrical magnetic flux causes a current path for quickly charging the traction battery. The magnetic flux causes heating of the components through which the current path is energized.

[0003] The components require a wire cross-section that is dimensioned sufficiently to achieve a low resistance and limit the heating during rapid charging to an acceptable value.

[0004] The charging socket of the vehicle and the charging plug of the charging device form the plugged-in interface in the current path. In particular, due to changes on the surfaces of the charging interface and the charging plug, a transfer resistance may be generated at the interface, which may cause more severe heating of the interface during rapid charging than in the rest of the current path.

[0005] In order to avoid damage at the interface, the temperature of the charging socket and the charging plug can be monitored and the charging power can be reduced, that is, the magnetic flux can be limited, when a specific temperature threshold is exceeded. Summary of the Invention

[0006] Therefore, the object of the present invention is to provide a method and a corresponding device for charging an electrically driven vehicle using devices that are as simple as possible in design.

[0007] This object is solved by the subject matter of the independent claims. Advantageous refinements of the present invention are described in the dependent claims, the description and the drawings. In particular, the independent claims of one claim category can also be refined analogously to the dependent claims of another claim category.

[0008] A method for charging an electrically driven vehicle is introduced, in which the maximum charging current of the charging process is pre-determined on the basis of the resistance ascertained during at least one previous charging process of at least one interface component of the interface between the charging device and the vehicle before the charging process for charging the vehicle.

[0009] "Charging of a vehicle" can refer to the charging of the traction battery of a vehicle. A releasable interface can be arranged between the charging device and the traction battery. The charging interface and the charging plug can be interface components of the interface. The interface components can be plugged together and released again. The interface components can have a plurality of plug connectors. A charging cable can be arranged between the charging device and the vehicle. The charging cable can have at least one feeder and one return line for transmitting electrical energy. The charging cable can also have data lines and signal lines. The conductors can be conductively connected and separated again at the interface. The charging cable can be a component of the charging device and be plugged onto the vehicle via the interface. The charging cable can also be plugged onto the vehicle via a first interface and onto the charging device via a second interface. Then, at least two interfaces are arranged between the charging device and the traction battery. The solutions presented here can be used at each arbitrary interface. The charging device can for example be manufactured as a wall box or as a charging station.

[0010] The charging process can be a certain time interval in which the interface components are connected to each other and the charging current flows through the feeder and the return line. The charging current is the electric magnetic flux for transmitting electric power from the charging device to the traction battery or the charging electronics of the traction battery. The maximum charging current can be a preset maximum value for the charging current. The maximum charging current limits the maximum possible transmitted power. The actual charging current may be less than the maximum charging current.

[0011] If the resistance of only one of the interface components is known, the maximum charging current can also be determined in advance. Thus, for example, a vehicle using the solutions presented here can also be charged on a conventional charging device. Conversely, a conventional vehicle can be charged on a charging device using the solutions presented here.

[0012] The maximum charging current can be pre-determined based on the resistance of at least one interface component of the charging device and the resistance of at least one interface component of the vehicle. If the interface is arranged between the cable and the vehicle, the maximum charging current can be pre-determined based on the resistance of at least one interface component of the cable and the resistance of at least one interface component of the vehicle. If the interface is arranged between the cable and the charging device, the maximum charging current can be pre-determined based on the resistance of at least one interface component of the cable and the resistance of at least one interface component of the charging device. The maximum charging current can be pre-determined based on two different resistances of the mutually connected interface components. Since the vehicle can be charged on different charging devices, different maximum charging currents can also be pre-determined on different charging devices. Similarly, different vehicles can be charged on the same charging device and different maximum charging currents can be pre-determined for different vehicles on the same charging device. By using the resistances of the two interface components, the maximum charging current can be pre-determined with increased accuracy.

[0013] During the current charging process, a resistance determination step for determining the current resistance of the interface can be performed using the current temperature of the interface and the current charging current flowing through the interface. The determined resistance can be used for the next charging process. By determining the resistance during the charging process, it is possible to track the stored resistance value used to limit the charging current due to the aging of at least one of the interface or the interface components. The resistance can be determined using a model. The model can be based on measurements of the resistance under defined framework conditions. The model can use at least one of the current temperature and the current charging current of the interface component as input quantities and provide the estimated resistance as an output quantity.

[0014] The resistance of the interface can be determined using the vehicle resistance value provided by the vehicle, which represents the estimated resistance of the interface component of the vehicle, and the charging device resistance value provided by the charging device, which represents the estimated resistance of the interface component of the charging device. The resistance values can be stored from one charging process to the next. The estimated resistances of the interface components can be added together. Through the transformed counterparts at the interface, other maximum charging currents can be pre-determined respectively.

[0015] It is possible to estimate the current resistance of the interface component of the vehicle using the current resistance of the interface and the resistance value of the charging device saved in the charging device during the previous charging process. It is possible to estimate the current resistance of the interface component of the vehicle in the charging device. All necessary values are present in the charging device for this purpose. The current resistance of the interface component of the vehicle can be depicted in the updated axle resistance value and provided by the charging device for the vehicle. The vehicle resistance value can be provided via the interface. The vehicle resistance value can also be provided via other communication paths. During the current charging process, the vehicle resistance value saved in the vehicle can be updated using the estimated resistance of the interface component of the vehicle.

[0016] It is possible to estimate the current resistance of the interface component of the charging device using the current resistance of the interface and the vehicle resistance value saved in the vehicle during the previous charging process. It is possible to estimate the current resistance of the interface component of the charging device in the vehicle. All required values are present in the vehicle for this purpose. The current resistance of the interface component of the charging device can be depicted in the updated charging device resistance value and provided by the vehicle for the charging device. The charging device resistance value can be provided via the interface. The charging device resistance value can also be provided via other communication paths. During the current charging process, the charging device resistance value saved in the charging device can be updated using the estimated resistance of the interface component of the charging device.

[0017] The method can be implemented, for example, in software form, or in hardware form, or in a hybrid form consisting of software and hardware, such as in a control device.

[0018] In addition, the solution presented here provides a control device that is configured to implement, control, or realize the steps of a variant of the method presented here in the corresponding mechanism.

[0019] The control device can be an electrical device, which has at least one computing unit for processing signals or data, at least one storage unit for storing signals or data, and at least one interface and / or communication interface for reading in or outputting data embedded in a communication protocol. The computing unit can be, for example, a signal processor, a so-called system ASIC, or a microcontroller for processing sensor signals and outputting data signals based on the sensor signals. The storage unit can be, for example, a flash drive, an EPROM, or a magnetic storage unit. The interface can be configured as a sensor interface for reading in sensor signals from sensors and / or as an actuator interface for outputting data signals and / or control signals to actuators. The communication interface can be configured to read in or output data wirelessly and / or wired. The interface can also be a software module that exists, for example, on a microcontroller in addition to other software modules.

[0020] Also advantageous is a computer program product or a computer program having program code that can be stored on a machine-readable carrier or storage medium, such as a semiconductor memory, a hard disk memory, or an optical memory, and in particular, when the program product or the program is executed on a computer or a device, is used to implement, realize, and / or control the steps of the method according to one of the previously described embodiments. Description of the Drawings

[0021] An advantageous embodiment of the present invention will be explained below with reference to the drawings. Among them:

[0022] Figure 1 A diagram showing the interface between a first interface component and a second interface component; and

[0023] Figure 2 A diagram showing the charging process in the case of using the method according to an embodiment.

[0024] The drawings are only schematic diagrams and are only used to explain the present invention. Identical or identically acting elements are consistently provided with the same reference numerals.

[0025] Detailed Description

[0026] For easier understanding, in the following description, the reference numerals regarding Figure 1-2 will be retained as references.

[0027] Figure 1A diagram of the interface 100 between the first interface component 102 and the second interface component 104 of the interface 100 is shown. The interface 100 is arranged in the wire 106 between two users A and B during the charging process. The user A can be, for example, a charging device 108 and the user B can be the traction battery of the vehicle 110. Similarly, the user A can be the traction battery of the vehicle 110 and the user B can be the charging device 108. Each of the users A and B has a control device (not shown here) for controlling the charging process. The control devices are configured to exchange data with each other and to predetermine the maximum charging current I flowing through the interface 100 based on the aging state of the interface components 102 and 104 before the start of the charging process. MAX .

[0028] The interface components 102 and 104 are configured as plug connectors. Here, the first interface component 102 is configured as a socket, for example, while the second interface component 104 is configured as a plug. Here, for simplicity, only one wire 106 of the interface 100 is shown. The interface 100 can have multiple additional wires 106. At least the interface 100 can have a feeder and a return line for transmitting the charging power for charging the traction battery.

[0029] The electric magnetic flux I flowing through the wire 106 A / B flows through the contact surface 112 between the interface components 102 and 104. Due to the transfer resistance R on the contact surface 112 K , a voltage U K drops on the contact surface 112, and the contact surface 112 heats up due to the generated power loss P V . Therefore, different voltages U A , U B can be measured at the users A and B, respectively. The electric magnetic flux I of the electricity at the users A and B A / B remains the same. Here, the electric magnetic flux I of the electricity at the two users A and B A / B can be measured separately. Due to the measurement accuracy, slightly different values for the electric magnetic flux I of the electricity flowing through the interface 100 A / B are generated here.

[0030] The interface components 102 and 104 are monitored for temperature. A first temperature value T A is collected at the first interface component 102. A second temperature value T B is collected at the second interface component 104. Since the temperature values T A , T B, so the temperature T of the contact surface 112 K may be different from the temperature value T A 、T B 。

[0031] Using the existing measured values, the transfer resistance R K and the loss power P V 。

[0032] The transfer resistance R K depends on the state of the contact surface 112. The state of the contact surface 112 is in turn determined by the state of the surfaces of the interface components 102, 104 that constitute the contact surface 112. For example, the surface may age due to environmental influences and may be at least partially covered by an oxide layer with a high resistance. Similarly, the coating that improves the transfer resistance R K of the surface may be damaged mechanically and / or thermally. If the temperature T of the contact surface 112 K at least locally and only briefly rises above the damage value due to the too high electrical flux I A / B flowing through the interface 100, then the coating may be damaged, for example. Such an overshoot can only be depicted with a delay by the temperature values T A 、T B , whereby when the temperature values T A 、T B have correspondingly high values, the coating may already be damaged.

[0033] With the solution presented here, such an overshoot of the temperature T of the contact surface 112 K can be actively prevented by pre-determining the maximum charging current I K for the current charging process taking into account the transfer resistance R MAX determined during the previous charging process.

[0034] Figure 2 shows a diagram of a charging process 200 carried out using the method according to an embodiment. The method can be applied, for example, at the interface as shown in Figure 1 . During the charging process 200, based on the resistance T A / B determined during at least the previous charging process of at least one of the interface components A, B of the interface 100 between the charging device 108 and the vehicle 110 before the charging process 200 for charging the vehicle 110, the maximum charging current I MAX。The previous charging process has ended before the current charging process 200 starts. The interface 100 has been separated between the previous charging process and the current charging process 200. In one embodiment, the previous charging process has been performed in combination with other charging devices or other vehicles. The interface 100 is also separated between the current charging process 200 and the next charging process.

[0035] The resistor R A / B Here, it consists of the resistor R of the first interface component A A and the resistor R of the second interface component B B The charging device 108 provides the resistor value R of the resistor R of the first interface component A during the previous charging process A depicting the charging device A,n , while the vehicle 110 provides the resistor value R of the resistor R of the second interface component B during the previous charging process B depicting the vehicle B,m . The resistor values R A,n 、R B,m are combined and the maximum charging current I for the current charging process 200 is predetermined MAX .

[0036] During the current charging process 200, the actual magnetic flux I and temperature T of the first interface component A are detected in the charging device A, and temperature T A, . In the case of using the model of the interface 100, the current resistance R of the interface is estimated during the current charging process 200 K . Since the charging device resistor value R A,n is known, the estimated resistor value of the second interface component B during the current charging process 200 can be determined using the current resistance R K depicting the estimated vehicle resistor value B for the estimated resistance R during the current charging process 200

[0037] In the vehicle, the actual magnetic flux I and temperature T of the second interface component B are detected during the current charging process 200 B , and temperature T B, . In the case of using the model of the interface 100, the current resistance R of the interface is estimated during the current charging process 200 K . Since the vehicle resistor value R B,m is known, the current resistance R can be used KDetermine the estimated resistance R of the first interface component A during the current charging process 200 A The estimated resistance value of the charging device depicted

[0038] The estimated vehicle resistance value And the estimated resistance value of the charging device Are exchanged during the data exchange 202 and used as the estimated values R A,n+1 、R B,m+1 In the case of using the corresponding at least one weighting factor to track the stored resistance values R A,n 、R B,m 。

[0039] In one embodiment, the tracked resistance values R A,n 、R B,m Are sent to the superior data processing system. There, the necessity of repairing the interface components A and / or B is estimated using the resistance values R A,n 、R B,m 。 Similarly, the resistance values R A,n 、R B,m Can be stored in the database, and through the database, a favorable pairing of the vehicle 110 and the charging device 108 can be found, for example. Therefore, for example, it can be avoided that a vehicle 110 with an interface component B as good as new is charged on a charging device 108 with a previously damaged interface component A

[0040] In other words, a method for determining the quality of the charging contact surface or for optimizing the charging strategy of an electric vehicle is introduced

[0041] The continuously increasing charging current in an electric vehicle makes it necessary to accurately determine the quality of the contact surface for transmitting the charging current to prevent thermal overload of the plug connection. The quality of the contact surface determines the transfer resistance on the plug pins here. Conventionally, the temperature of the contact can be determined and the charging current can be reduced according to the determined temperature. However, since the temperature can only be measured with a certain delay or lag time, the response time to a defective connection is limited and thermal overload cannot always be excluded

[0042] In the solution presented here, the measured pin temperature and the measured charging current are used to estimate the transfer resistance of the current plug connection. This value is continuously updated during the service life of the component, where the data exchange between the vehicle and the charging station is used to detect aging phenomena of the contact elements and thus determine the share of the transfer resistance on the vehicle side and the infrastructure side. Thereby, the current surface quality of each contact element participating in the charging process is determined and the charging strategy is adjusted predictively. That is to say, instead of when overheating is detected, the temperature-induced derating or reduction of the maximum charging current is already carried out in advance, thereby preventing premature aging of intact contact elements.

[0043] So far, reactive methods have been used to avoid overheating of the plug connection. For this purpose, the temperature of the contact element is continuously measured and the charging current is reduced in the case of too high a temperature. When the wear or damage of the contact element is very severe (which leads to a significantly increased transfer resistance of the plug connection), especially in the case of high charging currents such as 500 A and above, it is not always possible to reliably avoid temporary overheating of the contact and the accompanying further damage. In the most severe cases, when charging with severely worn contact elements on the infrastructure side, even the contact elements of the vehicle, such as the charging socket, are damaged. More precisely, it is now also possible to determine the transfer resistance, but there is a lack of knowledge about the contact surface state of the charging counterpart, so that the aging monitoring of its own contact elements cannot be carried out or can only be carried out imprecisely at most.

[0044] As an alternative, it is possible to use a charging socket in which particularly fast and precise temperature measurements can be carried out. However, the technical implementation of such temperature measurements is very cumbersome and expensive, especially if high dynamics of the measurement are to be achieved. The approach presented here of taking into account the measured data of the charging station can reduce the need for such expensive solutions, because the aging-induced and thus slowly occurring degradation of the contact can be continuously detected and the charging strategy can be adjusted preventively. The solution presented here can, for example, be integrated into future high-power charging infrastructures.

[0045] The "own" transfer resistance is continuously determined during each charging process and especially when the charging counterpart is replaced, whereby damage to intact contact elements during a charging attempt with a damaged charging counterpart can be prevented by adjusting the charging strategy before an increased temperature occurs.

[0046] For the solution presented here, the two parties involved in the charging process exchange the necessary data via communication between the vehicle and the infrastructure. This communication can be carried out here either wired via the interface or, as an alternative or supplement, wirelessly by means of radio or via the cloud.

[0047] The basis of the method shown here is to determine not only the contact temperature and charging current on the vehicle side but also the contact temperature and charging current on the infrastructure side, that is, on the charging station or wall box. The acquisition of these values has also been carried out with high precision to date.

[0048] Current measurement in the vehicle is one of the most important characteristic parameters to be determined in an electric vehicle. Current measurement on the infrastructure side is particularly necessary for the precise deduction of costs. (Keywords: calibration) The temperature of both aspects is an important function for safety to prevent overload in the case of high charging power. Here, independent measurements of the positive and negative poles are predefined according to the standard.

[0049] Thus, these measured values exist in control devices A and B as input information for determining the contact surface quality. The contact surface quality is directly related to the transfer resistance at the contact surface between components A and B here.

[0050] In the following, no distinction will be made specifically between the vehicle side and the infrastructure side, because the method can be applied equally to both aspects. Only a distinction is made between the parties involved in the charging process (A and B).

[0051] The transfer resistance between the charging contacts of A and B is directly depicted in the temperature measured on the contacts. Through the transfer resistance R K between the contacts, power loss directly related to the charging current I A / B occurs during charging.

[0052] P 损耗 = I A / B 2 · R K

[0053] To determine the power loss, the thermal model of the charging system is taken into account, which correlates the temperature values and the charging current with the power loss. For this purpose, the heat dissipation caused by the design, such as through active cooling or through the connected thermal inertia, such as cables or the vehicle body, should be taken into account. This characteristic can already be determined during the development of the components involved in the charging process under controlled conditions.

[0054] By recording the measurement results of the defined power loss and the temperature change curve over time on the contact element, a thermal equivalent circuit diagram composed of thermal resistance and heat capacity can be derived. Advantageously, this can be done at multiple locations throughout the thermal system. If a sufficiently accurate thermal equivalent circuit diagram is created, this model can be used as in the scenario presented here to "reverse" derive the recorded power loss from the temperature change curve.

[0055] In addition, to determine the power loss, the charging voltage of the charging pile can be compared with the measured voltage in the vehicle. The multiplication of the voltage difference and the charging current precisely yields the power loss. However, in this case, for example, the wire resistance has to be measured simultaneously, so this voltage measurement cannot be used alone to calculate the power loss at the plug contact.

[0056] Here it is assumed that the transfer resistance consists of the share specific to the surface of a single contact.

[0057] R K =R An +R B

[0058] At the beginning of the service life cycle of the charging contact, its specific share on the transfer resistance with R A,0 or R B,0 is determined and saved as an initial value in the control device of the corresponding charging user A or B. If a charging process is now carried out, the transfer resistance R K for this particular charging process is determined on both sides and the currently saved specific share R A or R B is deducted from it to determine an estimated value of the transfer resistance for the charging counterpart.

[0059] As a specific example, it is considered that A experiences a charging process for the first time (counting variable n = 0), which means that the initial value R A,0 has been saved. For this first charging process, the control device in A determines the total transfer resistance A ascertained by A through the current I A and the temperature T This total transfer resistance consists of the currently saved share R A,0 and the estimated share which is composed of.

[0060]

[0061] As the charging process ends, A transmits the estimated share to charging partner B and, in response, obtains the estimated value for its own share that is fed back. This process can be called "Voting" because the charging partners coordinate and evaluate each other.

[0062] The estimated value is now used by A to update the resistance share stored internally, thereby resulting in a new value R A,1 。

[0063]

[0064] The factor k is used here to standardize and weight the estimated resistance share. Since the quality of the current and temperature measurements varies at different charging partners and thus the accuracy of the estimated resistance share may also fluctuate, this estimated value is not accepted without further evaluation. For example, instead of using the actual resistance value, a comparable backup value is used, which represents the surface quality of the charging contact during standardization. The standardization can be displayed, for example, on a percentage scale with 100% = as-new contacts.

[0065] Now the new resistance share R A,1 is saved as the current value in the control device of A and used as the basis for share determination in the next charging process (n = 1). B implements the same method, so that the two users have updated their estimated resistance shares after the charging process. When changing charging partners, the result of this method is that the users learn from each other and can determine their own resistance shares with increased accuracy. As an example, a public fast charging station used daily by different vehicles can be assumed here. Thus, the deterioration of the contact surface quality caused by aging is gradually maintained at the charging station.

[0066] If the charging partners A and B are always the same, the share may be distorted because the aging of A may result in the same distribution of the increasing transfer resistance to the two users while the contact quality of B remains the same. The reason is that each user has the own contact quality of the previous charging process as the current value. However, if the contact quality has decreased since the previous charging process, i.e., the share of the transfer resistance has become larger, then this directly enters as an error into the voting and the increase in the own resistance is attributed to the partner.

[0067] Such extreme cases are compensated for by transformed charging pairs, since such errors are not aggregated but are distributed over a larger number of charging pairs and are likewise compensated for by these charging pairs. The significant aging of the contacts between two charging processes is regarded as an extreme case. As an alternative, the weighting factor k can be adjusted, which is reduced when charging is repeated with the same charging pairs, such that the corresponding errors do not accumulate with each charging cycle.

[0068] The method thus represents the following feasible solution, namely: for each charging contact (for which the temperature and current can be specifically determined), the aging phenomenon of the corresponding contact surface during the service life is determined for DC+ and DC- during DC charging.

[0069] Advantageously, this is particularly demonstrated in the case of a new electric vehicle with correspondingly new charging contacts. The vehicle is charged at a heavily used public charging station. It is to be assumed that the contacts of the charging station have contributed a significantly increased transfer resistance and thus rapid heating of all charging contacts occurs during high-power charging, for example during high-power charging at 500 A. Since the highly dynamic temperature measurement of the charging contacts can currently only be carried out very inadequately, the temperature on the charging contacts, especially directly on the contact surface, rises rapidly, which can be detected by integrated temperature measurement, but with a certain time delay and with reduced dynamics. Therefore, the measured temperature rise on the sensor does not correspond to the temperature rise at the contact, and the measured temperature on the sensor is particularly significantly lower than the temperature at the contact. Thus, if the sensor value is now reacted to and the charging current is reduced after the measured temperature rise, the temperature at the contact may already be significantly higher and thermal aging of the contact element may have occurred. For a new vehicle, this means that premature aging of the charging contacts occurs due to the lack of knowledge of the increased resistance share of the charging pairs. Therefore, in this case, a reactive charging strategy may not prevent damage / unnecessary aging of the charging contacts.

[0070] Now, with the method introduced, it is feasible for users A and B to exchange information in advance about the quality of their charging contacts and thus prophylactically adjust the charging strategy in order to prevent thermal aging of new contacts right from the start.

[0071] For this purpose, the same communication interface that is also required for said voting can be used. For this purpose, not only direct communication between the charging counterparts (e.g., via power line communication, CAN, or NFC) can be envisaged, but also cloud-based communication. In the latter variant, the contact quality can already be taken into account when looking for a suitable charging station.

[0072] Furthermore, the method provides suitable input information for a predictive maintenance scheme in which the charging contacts of the charging pile can be replaced before they can cause a thermal overload.

[0073] Since the devices and methods described in detail above are examples, they can be modified by those skilled in the art in a common manner within a wide range without departing from the scope of the invention. In particular, the mechanical arrangements and dimensional ratios of the individual elements relative to each other have been selected only by way of example.

[0074] List of reference numerals:

[0075] 100 Interface

[0076] 102 First interface component

[0077] 104 Second interface component

[0078] 106 Conductor

[0079] 108 Charging device

[0080] 110 Vehicle

[0081] 112 Contact surface

[0082] I A / B Electric magnetic flux

[0083] R K Transfer resistance

[0084] U K Voltage

[0085] P V Loss power

[0086] U A First voltage

[0087] U B Second voltage

[0088] T A First temperature value

[0089] T B Second temperature value

[0090] T KTemperature

[0091] I MAX Maximum charging current

[0092] 200 Charging process

[0093] 202 Data exchange

[0094] R A First resistor

[0095] R B Second resistor

[0096] R A,n Resistance value of the charging device

[0097] R B,m Resistance value of the vehicle

[0098] I A First magnetic flux linkage

[0099] Estimated resistance value of the vehicle

[0100] I B Second magnetic flux linkage

[0101] Estimated resistance value of the charging device

Claims

1. A method for charging an electrically driven vehicle, the method comprising: ascertaining the resistance of the interface using a vehicle resistance value provided by the vehicle, representing the estimated resistance of the interface component of the vehicle, and a charging device resistance value provided by the charging device, representing the estimated resistance of the interface component of the charging device; predetermining a maximum charging current for the charging process on the basis of the resistance ascertained during at least one previous charging process of at least one interface component of the interface between the charging device and the vehicle, prior to the charging process for charging the vehicle; and charging the vehicle on the basis of the predetermined maximum charging current; wherein during the current charging process, the current vehicle resistance value and the current charging device resistance value are ascertained using a model which uses the current temperature of at least one of the interface components of the vehicle and the interface components of the charging device and the current charging current as input variables and provides the estimated resistance as an output variable, and wherein the ascertained resistance is used for a subsequent charging process; and wherein the current resistance of the interface component of the vehicle is estimated using the current resistance of the interface and the charging device resistance value stored in the charging device during the previous charging process, and the current resistance of the interface component of the charging device is estimated using the current resistance of the interface and the vehicle resistance value stored in the vehicle during the previous charging process.

2. The method according to claim 1, wherein the maximum charging current is predetermined on the basis of the resistance of at least one interface component of the charging device and the resistance of at least one interface component of the vehicle.

3. The method according to claim 1, wherein the vehicle resistance value stored in the vehicle is updated during the current charging process using the estimated resistance of the interface component of the vehicle.

4. The method according to claim 1, wherein the charging device resistance value stored in the charging device is updated during the current charging process using the estimated resistance of the interface component of the charging device.

5. A control device configured to perform, implement and / or control the method according to any one of the preceding claims in a corresponding mechanism.

6. A computer program product configured to cause a processor to perform, implement and / or control the method according to any one of claims 1 to 4 when the computer program product is executed.

7. A machine-readable storage medium on which the computer program product according to claim 6 is stored.

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