CONTROL DEVICE FOR CONTROLLING THE CHARGING PROCESS OF AN ELECTRIC VEHICLE

Abstract

A control device (10) for an electric vehicle (5) for controlling a charging process of the electric vehicle (5) comprises a vehicle-side part (6) of a control pilot circuit (1) which is configured to influence a value of a control pilot voltage in a control pilot circuit in the event of a fault such that this is interpreted by a charging station-side part (3) of the control pilot circuit (1) connected via a control pilot connection (4) as a disconnection of the control pilot connection (4). In particular, an emergency stop switch (7) may be provided in the vehicle-side part (6) of the control pilot circuit (1), which is closed during normal operation and is configured to be opened in the event of a fault in order to interrupt the control pilot circuit.

Description

[0001] The present invention relates to the field of electric vehicles. In particular, the invention is directed to a control device for controlling a charging process of an electric vehicle, especially with a control-pilot circuit.

[0002] A key focus in the development of electric or hybrid vehicles, especially those at least partially powered by electric motors, is the battery that powers the electric motor (hence also called "drive battery" or "traction battery"). Various battery cells have been developed for this purpose, such as lithium-ion cells. It should be understood that the term "battery" in the following refers specifically to a rechargeable battery ("accumulator" or "rechargeable battery"). Charging the battery of electric vehicles is a central aspect of using these vehicles and can be done in various ways.

[0003] An electric vehicle can, for example, be charged simply by using a standard household outlet as a "charging station." This type of charging is best suited for occasional use or overnight charging, as no additional installation is required. There are also dedicated wall-mounted charging stations, also known as wallboxes, designed for private or semi-public use. These are safer and more efficient, offering faster charging times, making them a popular choice for home use. In addition, public charging stations are available, located in parking garages, on the street, or in supermarket parking lots. Public charging stations are particularly convenient for charging while parked in the city or while shopping. Furthermore, there are fast-charging stations that allow a vehicle to be charged in a very short time.

[0004] Various plug types and charging modes for electric vehicles are regulated, in particular, by the international standard IEC 62196, for example, the Type 2 plug. The Type 2 plug has three live conductor contacts L1, L2, and L3, a neutral contact, and a protective earth (PE) contact. It also features the PP contact (Proximity Pilot or Plug Present) to detect the presence of the plug and the Control Pilot (CP) contact to exchange control signals between the electric vehicle and the charging station. The Control Pilot is part of the communication system between the electric vehicle and the charging station. It serves to control the charging process and ensure that the vehicle and the charging station are properly and safely connected.

[0005] If the CP detects a secure connection between the charging station and the vehicle, the charging process can take place, for example, via the electric vehicle's onboard charger (OBC). The OBC monitors and controls the entire charging process and is primarily responsible for converting alternating current (AC) to direct current (DC). It also ensures that the battery is charged efficiently and safely by, for example, adjusting the charging speed, stopping the charging process when the battery is full, and monitoring the battery temperature.

[0006] Charging stations and vehicles are typically equipped with protective mechanisms that stop the charging process if a fault is detected (e.g., reverse polarity, communication error, overheating, overvoltage, short circuit, etc.). Safety mechanisms are also necessary for charging infrastructures that do not differentiate between AC and DC charging plugs. If these protective mechanisms fail, the charging process can continue despite a potentially dangerous situation. For example, a charging station might apply the maximum possible DC voltage, even if the vehicle is not designed for it.

[0007] However, a certain amount of time, e.g., several seconds, can often pass before a shutdown mechanism engages, potentially causing damage to the vehicle. According to the standard for electric vehicle charging stations (IEC 61851), a rapid and immediate shutdown, specifically within 100 milliseconds, is only required if the charging plug is disconnected during active charging, as this can pose a life-threatening situation in the high-voltage system. Disconnection of the plug is primarily detected by the interruption of the CP connection.

[0008] A common CP circuit, known to experts (see also Fig. 1) The charging station (on the vehicle side) has a diode which is connected to a protective conductor via a (first) resistor (usually 2740 ohms). When the CP connection between the charging station and the electric vehicle is established, i.e., when a charging plug is inserted into the charging socket of the electric vehicle, the CP line of the charging cable is connected to the protective conductor via the diode and the resistor. This signals to the charging station that the vehicle is connected. The CP voltage at the charging station drops from 12 V, which is present when the vehicle is not running. By switching on a further resistor (usually 1300 or 270 ohms) in the CP circuit in the vehicle, the active charging process is started, i.e., the current flow begins. Communication between the charging station and the vehicle takes place via pulse-width modulation of a square wave voltage, a principle familiar to those skilled in the art.When the CP connection is disconnected by unplugging the charging plug, the CP voltage at the charging station, which initially dropped from 12 V when the CP connection was established, rises again to the open-circuit voltage of 12 V, causing the HV voltage to be switched off immediately.

[0009] It is an object of the present invention to provide an improved control device for controlling the charging process of an electric vehicle. In particular, it aims to increase safety during a charging process.

[0010] The solution to this problem is achieved according to the teaching of the independent claims. Various embodiments and further developments of the invention are the subject of the dependent claims.

[0011] A first aspect of the invention relates to a control device for an electric vehicle for controlling a charging process of the electric vehicle (in particular its traction battery). The control device comprises a vehicle-side part of a control-pilot circuit which is configured, in the event of a fault, to influence a value of the control-pilot voltage in a control-pilot circuit such that this is interpreted by a charging station-side part of the control-pilot circuit, connected via a control-pilot connection, as a disconnection of the control-pilot connection, i.e., in particular, as the unplugging of a charging plug, especially in accordance with the standard IEC 61851.

[0012] The invention is therefore based in particular on the provision of a control unit with a modified control-pilot circuit in an electric vehicle. In the event of a fault, the control-pilot circuit, or more precisely the vehicle-side part thereof, can influence the control-pilot voltage to simulate a disconnection of the CP connection and thus essentially an unplugging of the charging connector. This voltage change, like an actual unplugging of the charging connector, is detected by a charging station due to the standard continuous monitoring of the CP voltage during the charging process. According to the standard, the charging station must then be de-energized within a very short time (in particular 100 ms). According to the standard, this is also the only way to bring about such a rapid shutdown ("emergency shutdown").

[0013] The control unit thus enables a simple, improved safety mechanism with a very short reaction time. It can utilize existing processes, particularly those implemented in the relevant standard. This can be especially relevant for specific functional safety requirements, for example, if the positive and negative terminals of the high-voltage supply are reversed in the charging station. The very rapid emergency shutdown reduces the risk of damage to the vehicle. The control unit is particularly advantageous for chargers controlling DC charging processes, but it can also coordinate both AC and DC charging processes.

[0014] The term "charging process" refers specifically to the period during which an electric vehicle is connected to a charging station. The charging process thus begins when the vehicle is connected to a charging station and ends when the connection is disconnected, which can be detected, in particular, by a control-pilot connection. During the charging process, current does not necessarily flow to the traction battery at all times. The term "charging station" encompasses all facilities that can be used to charge an electric vehicle. Examples of these were mentioned earlier. A charging station can also be referred to as "Electric Vehicle Supply Equipment" (EVSE).

[0015] The term "vehicle" as used here refers specifically to a passenger car, including all types of motor vehicles, hybrid and battery-powered electric vehicles, as well as vehicles such as sedans, vans, buses, trucks, delivery vans, and the like. The term "electric vehicle" (EV) then refers specifically to electric or hybrid vehicles, particularly vehicles that are at least partially powered by an electric motor. An electric vehicle can be, in particular, a passenger car, but also a vehicle such as a van, bus, truck, delivery van, and the like, or a two-wheeler, such as an (electric) motorcycle, (electric) scooter, e-bike, e-scooter, and the like. As mentioned at the outset, an electric vehicle is primarily powered by its traction battery.

[0016] The terms “comprises”, “includes”, “includes”, “has”, “with”, or any other variant thereof, as used herein, are intended to cover non-exclusive inclusion. For example, a method or apparatus that includes or has a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent in such method or apparatus.

[0017] Furthermore, unless explicitly stated otherwise, "or" refers to an inclusive or and not an exclusive "or". For example, a condition A or B is satisfied by one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

[0018] The terms "ein" or "eine," as used here, are defined as "one or more." The terms "ein anderer" and "ein Weitere," as well as any other variant thereof, are to be understood as "at least one more."

[0019] The term "plural", as used here, is to be understood in the sense of "two or more".

[0020] The terms "configured" or "set up" to perform a specific function (and their respective variations) are understood within the meaning of the invention to mean that the corresponding device already exists in a configuration or setting in which it can perform the function, or at least that it is adjustable—i.e., configurable—so that it can perform the function after appropriate adjustment. Configuration can be achieved, for example, by adjusting parameters of a process sequence or by using switches or similar devices to activate or deactivate functionalities or settings. In particular, the device can have several predetermined configurations or operating modes, so that configuration can be carried out by selecting one of these configurations or operating modes.

[0021] Preferred embodiments of the control device according to the first aspect are described below, which, unless expressly excluded or technically impossible, can be combined with each other as desired and with the other described aspects of the invention.

[0022] In some embodiments, the vehicle-side part of the Control Pilot circuit is configured to raise the Control Pilot voltage to the value of a Control Pilot open-circuit voltage, in particular 12 V, in the event of a fault. If the CP voltage (suddenly) reaches this open-circuit value, this is interpreted according to the standard as if the charging plug had been disconnected, resulting in immediate shutdown.

[0023] In some embodiments, an emergency stop switch is provided in the vehicle-side part of the control-pilot circuit. This switch is closed during normal operation and is designed to open in the event of a fault to interrupt the circuit within the control-pilot circuit. The control-pilot circuit, which can be designed in a known manner, thus additionally features an emergency stop switch that serves to simulate the disconnection of the charging plug. This occurs upon detection of a fault by (automatically) opening the emergency stop switch, which is normally closed during normal operation, thereby interrupting the circuit within the control-pilot circuit. This causes, in particular, an increase in the control-pilot voltage, specifically to the open-circuit value of 12 V, so that, as explained in accordance with the standard, an immediate shutdown of the high-voltage voltage takes place.

[0024] In some designs, the emergency stop switch includes a transistor. A CP circuit is typically a 12 V circuit, so the emergency stop switch can be implemented as a simple transistor. The transistor is normally closed during normal operation. Opening the transistor interrupts the CP circuit, thus simulating, as explained above, the unplugging of the charger.

[0025] The emergency stop switch can be located at various points in the CP circuit, or more precisely, in the vehicle-side part of the CP circuit, in order to interrupt the CP circuit in the event of a fault, as described above. This causes the CP voltage at the charging station, which initially drops from 12 V when the CP connection is established, to rise back to the open-circuit value of 12 V, resulting in the immediate shutdown of the HV voltage.

[0026] In some embodiments, the emergency stop switch is connected upstream of the diode in the CP circuit. In some alternative embodiments, the emergency stop switch is located between the diode and the (first) resistor of the CP circuit. In some alternative embodiments, the emergency stop switch is located downstream of the (first) resistor of the CP circuit. In some alternative embodiments, the emergency stop switch is again located in the protective conductor of the CP circuit.

[0027] In some embodiments, the control unit further includes a fault detection device, which is connected to the emergency stop switch and configured to detect a fault and, in the event of a fault, transmit a fault signal to the emergency stop switch to open it. The fault detection device can, for example, be configured to recognize an overvoltage or reverse polarity as a fault. Other fault scenarios are conceivable, particularly those where a rapid emergency shutdown is advantageous. For example, suitable software can then generate a fault signal and transmit it to the emergency stop switch, causing it to open and thereby triggering the emergency shutdown.

[0028] A second aspect of the invention relates to a method, particularly a computer-implemented method, for controlling a charging process of an electric vehicle, which has a control device according to the first aspect, wherein in the event of a fault a value of the control pilot voltage in a control pilot circuit is influenced in such a way, in particular raised to an open-circuit value, that this is interpreted by a charging station-side part of the control pilot circuit connected via a control pilot connection as a disconnection of the control pilot connection, in particular according to the standard IEC 61851.

[0029] A third aspect of the invention relates to a method, particularly a computer-implemented method, for controlling the charging process of an electric vehicle, which includes a control device according to the first aspect with an emergency stop switch, wherein the emergency stop switch is opened upon detection of a fault, thus interrupting the circuit in the control-pilot circuit. The opening occurs, in particular, automatically by means of a corresponding fault signal, i.e., without user intervention.

[0030] A fourth aspect of the invention relates to an electric vehicle with a control device according to the first aspect.

[0031] The features and advantages explained in relation to the first aspect of the invention also apply accordingly to the other aspects of the invention.

[0032] Further advantages, features and possible applications of the present invention will become apparent from the following detailed description in conjunction with the drawings.

[0033] This shows: Fig. 1 a circuit diagram of a control-pilot circuit known from the prior art; Fig. 2 schematically a control device according to one embodiment; and Fig. 3 different variants of the vehicle-side part of a control pilot circuit with emergency stop switch.

[0034] In Fig. Figure 1 shows a circuit diagram of a conventional control-pilot circuit 1 known from the prior art. This comprises a charging station-side part 3 in a charging station 2 and a vehicle-side part 6 in an electric vehicle 5, which are configured as shown in Figure 1. Fig. 1 shown via a control pilot connection 4 in a charging cable are connected to each other, so that the control pilot circuit is closed.

[0035] Between the pilot contact CP and the protective conductor PE, the charging station 2 initially applies an (open-circuit) voltage of 12 V. When the electric vehicle 5 is connected via a charging cable, a square wave voltage is applied across a 1 kΩ resistor (R1). On the electric vehicle 5 side, the circuit between CP and PE is closed by a resistor (R3) connected in series with a diode D. A pulse-width modulation (PWM) generator is used to produce a pulse-width modulation of the square wave voltage, which the charging station 2 uses to signal to the vehicle 5 the maximum current that the charging station 2 can supply.

[0036] The electric vehicle 5 communicates with the charging station 2 via the selection of resistors and the associated change in the voltage drop across resistor R1. Specifically, resistor R3 (2740 Ω) signals that a connection to vehicle 5 has been established (although no current is yet flowing). Closing switch S2 then signals, via resistor R2, that vehicle 5 is ready for charging (possibly with ventilation).

[0037] During the charging process, charging station 2 continuously monitors the voltage Va. This allows it to detect, in particular, when the voltage Va rises back to the open-circuit value of 12 V. This occurs especially if the charging plug is, for example, forcibly or accidentally disconnected while charging current is flowing, thereby disconnecting the CP connection 4 and thus interrupting the CP circuit. Since this can be a particularly dangerous situation, an emergency shutdown within 100 ms is provided in accordance with the IEC 61851 standard.

[0038] Other fault conditions, such as reverse polarity or overvoltage, may also be detected by the system. However, a shutdown by a conventional safety mechanism may then occur much more slowly.

[0039] To ensure an immediate emergency shutdown even in these cases, an emergency stop switch 7 is provided in the vehicle-side part 6 of the CP circuit 1, as described below with reference to Fig. 2 and Fig. 3 explained.

[0040] In Fig. Figure 2 schematically illustrates a control unit 10. This unit includes, in particular, the vehicle-side part 6 of the CP circuit 1. Furthermore, a fault detection device 8 is provided, which is connected to the emergency stop switch 7 via a data line 9. The fault detection device 8 can, for example, detect an overvoltage or a reverse polarity and generate a corresponding fault signal, which is used to control the emergency stop switch 7. The fault signal is transmitted via the data line 9 to the emergency stop switch 7, which is normally closed, in order to open it. Suitable software can be used for this control. Opening the emergency stop switch 7 interrupts the CP circuit and thus simulates a (mechanical) disconnection of the charging plug, i.e., a separation of the CP connection 4.

[0041] The emergency stop switch 7, which is designed in particular as a transistor, can be arranged at various locations in the vehicle-side part 6 of the CP circuit 1. According to the variant from Fig. 2 The emergency stop switch 7 is connected upstream of diode D. Further variants are described in Fig. 3 shown. According to the variant from Fig. 3a The emergency stop switch 7 is arranged between diode D and resistor R3. According to the variant from Fig. 3b, the emergency stop switch 7 is connected downstream of resistor R3. According to the variant from Fig. In section 3c, the emergency stop switch 7 is again located in the protective conductor. The vehicle body 5 serves as the ground.

[0042] While at least one exemplary embodiment has been described above, it should be noted that a large number of variations exist. It should also be noted that the described exemplary embodiments are merely non-limiting examples, and it is not intended to restrict the scope, applicability, or configuration of the devices and methods described herein. Rather, the preceding description will provide the person skilled in the art with guidance for implementing at least one exemplary embodiment. It is understood that various modifications to the function and arrangement of the elements described in an exemplary embodiment can be made without derogating from the subject matter defined in the appended claims and their legal equivalents. REFERENCE MARK LIST 1 CP circuit 2 charging stations 3. Charging station-side part of the CP circuit 4 CP connection 5 Electric vehicle 6. Vehicle-side part of the CP circuit 7 emergency stop switches 8 Fault detection device 9 data lines 10 Control unit

Claims

Control device (10) for an electric vehicle (5) for controlling a charging process of the electric vehicle (5), wherein the control device (10) comprises a vehicle-side part (6) of a control pilot circuit (1) which is configured to influence a value of a control pilot voltage in a control pilot circuit in the event of a fault such that this is interpreted by a charging station-side part (3) of the control pilot circuit (1) connected via a control pilot connection (4) as a disconnection of the control pilot connection (4). Control device according to claim 1, wherein the vehicle-side part (6) of the control pilot circuit (1) is configured to raise the value of the control pilot voltage to a value of a control pilot open-circuit voltage in the event of a fault. Control device according to claim 1 or 2, wherein an emergency stop switch (7) is provided in the vehicle-side part (6) of the control pilot circuit (1), which is closed in normal operation and is configured to be opened in the event of a fault in order to interrupt the circuit in the control pilot circuit (1). Control device according to claim 3, wherein the emergency stop switch (7) comprises a transistor. Control device according to claim 3 or 4, wherein the emergency stop switch (7) is connected upstream of a diode (D) of the control pilot circuit (1). Control device according to claim 3 or 4, wherein the emergency stop switch (7) is arranged between a diode (D) and a resistor (R3) of the control pilot circuit (1). Control device according to claim 3 or 4, wherein the emergency stop switch (7) is connected downstream of a resistor (R3) of the control pilot circuit (1). Control device according to claim 3 or 4, wherein the emergency stop switch (7) is arranged in a protective conductor of the control pilot circuit (1). Control device according to one of the preceding claims, further comprising a fault detection device (8) which is connected to the emergency stop switch (7) and is configured to detect a fault and, in the event of a fault, to transmit a fault signal to the emergency stop switch (7) in order to open it. Method for controlling a charging process of an electric vehicle (5) which has a control device (10) according to one of the preceding claims, wherein in the event of a fault a value of a control pilot voltage in a control pilot circuit is influenced in such a way that this is interpreted by a charging station-side part (3) of the control pilot circuit (1) connected via a control pilot connection (4) as a disconnection of the control pilot connection (4). Method for controlling a charging process of an electric vehicle (5) which has a control device (10) according to one of claims 3 to 9, wherein the emergency stop switch (7) is opened when a fault is detected, so that the circuit in the control pilot circuit (1) is interrupted. Electric vehicle (5) with a control device (10) according to one of claims 1 to 9 .

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