Circuit arrangement for monitoring respective temperature of plurality of charging contacts of charging plug

Abstract

The invention relates to a circuit arrangement (1) for monitoring the temperature of a plurality of charging contacts (2) of a charging plug (3) of an electric or hybrid vehicle, comprising: a plurality of temperature-dependent resistors (4), each of which is associated with a charging contact (2) and can be thermally coupled thereto; a plurality of constant resistors (5), each having a constant resistance value, each temperature-dependent resistor (4) being connected in series to one of the constant resistors (5), a parallel circuit being provided in which series circuits formed by a respective temperature-dependent resistor (4) and a respective constant resistor (5) are connected in parallel to each other, the constant resistors (5) all have different resistance values from one another, and a voltage measuring device (6) is provided, by means of which a voltage drop can be determined over the parallel circuit. As a result, it is possible to determine, in a simple and reliable manner, which of a plurality of charging contacts of a charging plug for an electric or hybrid vehicle generates critical heat during operation.

Description

Technical Field

[0001] The invention relates to a circuit arrangement for monitoring the respective temperatures of a plurality of charging contacts of a charging plug of an electric or hybrid vehicle, the circuit arrangement having a plurality of temperature-dependent resistors which are respectively assigned to the charging contacts and can be connected to the charging contacts. Background Art

[0002] Electric vehicles and hybrid vehicles have a rechargeable energy storage device, usually a high-voltage battery, which supplies energy to the drive motor during driving operation. The energy storage capacity of the high-voltage battery is limited, so that the high-voltage battery must be recharged at a charging station at regular intervals. The battery is charged via a charging cable arranged between the charging station and the vehicle, wherein the charging cable (for example, according to the European standard IEC 62196 type 2) is provided on one side with a charging plug that can be inserted into a charging socket arranged at the charging station, and on the other side with a charging adapter that can be connected to an internal charging plug installed in the electric vehicle and hybrid vehicle. In this document, the charging socket, charging plug, charging adapter and internal charging plug are all covered by the term "charging plug connector". The charging socket and the charging adapter have contact sleeves as charging contacts, and the charging plug and the internal charging plug that can be installed in the electric vehicle or hybrid vehicle have contact pins that can be inserted into the contact sleeves as charging contacts.

[0003] Charging connectors for electric and hybrid vehicles must meet regulatory requirements and user-specific requirements, which involve temperature monitoring of AC charging contacts and DC charging contacts. For DC charging, temperature measurement is usually required at the two DC charging contacts. To this end, in order to enable real-time temperature monitoring for charging optimization and safety monitoring, structural elements suitable for temperature measurement (usually NTC resistors) are arranged as close to the heat source, i.e. the charging contacts, as possible. NTC resistors are resistors used in electronic components. NTC resistors are also called thermistors or thermal conductors. The abbreviation "NTC" stands for "negative temperature coefficient" and describes the property of a thermal conductor that conducts current better as the temperature increases, because the thermal conductor has a negative temperature coefficient.

[0004] For AC charging, either NTC temperature measurement or simpler PTC temperature monitoring is usually required. PTC resistors (also called cold conductors or PTC thermistors (“positive temperature coefficient”)) are also temperature-dependent resistors, but they conduct current better at low temperatures than at high temperatures.

[0005] The difference between using PTC elements and NTC elements is that NTC elements enable real temperature measurement, while PTC elements usually have a nonlinear resistance behavior starting from a temperature threshold and can therefore be used to signal that a critical temperature has been exceeded. PTC elements can therefore be used to implement a type of "safety" in that if a critical temperature is exceeded, the PTC element feeds back a sudden change in value to the reading system.

[0006] Whether a real temperature measurement is required or only a detection of whether a temperature threshold is exceeded depends on the standard and manufacturer specifications. For all AC charging contacts (e.g. L1, L2, L3 and N in a plug connector according to European standard IEC 62196 type 2), this may require individual measurements for each AC charging contact or may require a bundled measurement, i.e. a common measurement for all AC charging contacts.

[0007] DE 10 2015 106 251 A1 describes a temperature monitoring device, which has a carrier element extending flatly along a plane and having an opening. For this purpose, the carrier element can be designed as a circuit board. The contact element is a component of a contact assembly, and the contact assembly can be attached to the plug insert as a module unit. The contact assembly has a temperature monitoring device with a carrier element. The temperature monitoring device is used to detect any unallowed heating at the contact element for transmitting a strong current at least when the plug connector part is working. For the necessary contact, the carrier element has a metal coating at the opening for providing a contact surface in the form of a feed-through contact. The sensor device 432 is arranged at the connection section, and the connection section guides the heat of the contact element to the sensor device. The conductor track is guided from the sensor device to the upper control device. At the control device, the sensor signal generated by the sensor device can be evaluated so that the current flowing through the contact element is controlled according to the sensor signal. The sensor device can be set for each contact element to be monitored, so that the temperature can be monitored separately at each contact element to be monitored and heating can be detected.

[0008] WO 2021 / 004765 A1 describes an electrical component with a temperature monitoring device. Here, a plug connector component is described that has both an alternating current (AC) charging contact and a direct current (DC) charging contact. In order to monitor possible heating, especially at the direct current (DC) charging contacts, the plug connector component has an electrical component. The component is formed by contact elements arranged on a carrier element and electrically connected to the assigned load wires. To this end, each contact element is received in a receiving opening of the assigned carrier element. The temperature monitoring device has a temperature sensor. The temperature monitoring device is fixed to the surface of the carrier element. The heat of the contact element is conducted to the temperature monitoring device. Summary of the invention

[0009] The object of the present invention is therefore to determine in a simple and reliable manner which of a plurality of charging contacts of a charging plug for an electric or hybrid vehicle experiences critical heating during operation.

[0010] This object is achieved by the subject matter of the independent claim. Preferred developments of the invention are described in the dependent claims.

[0011] Therefore, according to the present invention, a circuit device is provided for monitoring the respective temperatures of a plurality of charging contacts of a charging plug for an electric vehicle or a hybrid vehicle, the circuit device having a plurality of temperature-dependent resistors and a plurality of constant resistors, wherein the plurality of temperature-dependent resistors are respectively assigned to each charging contact and can be thermally coupled to the charging contacts, and the plurality of constant resistors each have a constant resistance value, wherein each temperature-dependent resistor is connected to one of the constant resistors, a parallel circuit is provided in which circuits formed by a respective temperature-dependent resistor and a respective constant resistor are connected in parallel with each other, the constant resistors all have resistance values ​​different from each other, and a voltage measuring device is provided by which a voltage drop across the parallel circuit can be determined.

[0012] According to a preferred improvement of the present invention, the circuit device is implemented in such a way that a plurality of temperature-dependent resistors and a plurality of constant resistors are provided, the temperature-dependent resistors are respectively assigned to the charging contacts and can be thermally coupled with the charging contacts, and the constant resistors each have a constant resistance value, wherein each temperature-dependent resistor is connected in series with one of the constant resistors, a parallel circuit is provided in which series circuits formed by a corresponding temperature-dependent resistor and a corresponding constant resistor are connected in parallel with each other, the constant resistors all have resistance values ​​different from each other, and a voltage measuring device is provided by which a voltage drop across the parallel circuit can be determined.

[0013] An important aspect of the design is therefore that the electrical path is "coded" by the respective temperature-dependent resistor, more precisely by means of a constant resistor whose resistance value differs from the resistance values ​​of all other constant resistors arranged in the path of the other temperature-dependent resistors. Thus, for each charging contact whose temperature is to be monitored, a series circuit of a temperature-dependent resistor and a constant resistor is realized, wherein the temperature-dependent resistor is provided for detecting the temperature of the respective charging contact. The series circuits are then connected in parallel with one another, so that the total resistance of the parallel circuit changes individually depending on which of the temperature-dependent resistors exhibits an increase in resistance value, because the charging contact corresponding to this resistor has heated up above a critical temperature.

[0014] According to a preferred improvement of the present invention, the present invention is alternatively implemented in that the circuit arrangement according to the present invention is additionally provided with a plurality of transistors, wherein a circuit is provided in which a temperature-dependent resistor is respectively connected to the base of a respective transistor and a constant resistor is respectively connected in series with the transistor via two further connections of the transistor, and a parallel circuit is provided in which circuits formed by a constant resistor, a respective transistor and a respective temperature-dependent resistor are connected in parallel with each other.

[0015] Therefore, according to this preferred design of the present invention, a transistor is used for each charging contact, which is pre-controlled by a circuit with a temperature-dependent resistor at its corresponding base. Here, the temperature-dependent resistor is preferably a PTC element or an NTC element. If the temperature-dependent resistor is a PTC element, the resistance value of the PTC element increases when a predefined temperature limit is reached at the charging contact, which causes the voltage at the base of the transistor to drop, so that the transistor is blocked. If an NTC element is used, it is applicable that the resistance value of the NTC element decreases when the temperature limit is reached at the charging contact, which causes the voltage at the base of the transistor to rise, so that the transistor is turned on. Therefore, the "coding" of the electrical path is achieved in the following way: the constant resistance of the corresponding electrical path is "switched on" or "cut off" by means of a transistor.

[0016] The preferred developments of the invention described below apply generally to the invention and therefore also to the two alternatives described above.

[0017] Preferably, the temperature-dependent resistors are all of the same type and the temperature dependence of resistors of this type is also the same. In this preferred embodiment of the invention, it is advantageous that it is not necessary to pay attention to whether the respective resistance values ​​of the temperature-dependent resistors and the constant resistors are always matched to one another in such a way that a single resistance value is achieved overall that enables the function according to the invention, i.e., it is possible to infer which temperature-dependent resistor is located at the charging contact whose temperature exceeds the critical temperature by means of the total resistance of the parallel circuit.

[0018] In principle, different temperature-dependent resistors can be used within the scope of the present invention. However, as mentioned above, according to a preferred improvement of the present invention, the temperature-dependent resistor is a PTC element or an NTC element. The resistance change process of a PTC element is generally nonlinear and can vary in the range of 618Ω to 1350Ω, for example, in a temperature range of -40°C to 90°C. Above 90°C, the resistance increases rapidly and significantly, so that at 100°C the resistance already reaches 10,000Ω. Therefore, the trigger threshold that can be used to detect the critical temperature is above 90°C / 1350Ω.

[0019] The present invention only requires that all constant resistors have different resistance values. However, if the resistance value of the constant resistor with the next smallest resistance value is at least twice the resistance value of the constant resistor with the smallest resistance value, the function of detecting the temperature-related resistance (a critical temperature rise has been detected) by the total resistance of the parallel circuit is particularly reliable. It is also preferably applicable that the corresponding difference between the resistance values ​​of all constant resistors is at least equivalent to the difference between the resistance value of the constant resistor with the next smallest resistance value and the resistance value of the constant resistor with the smallest resistance value. In other words, this means that the difference in the resistance values ​​of any two constant resistors is at least equal to the difference between the resistance value of the constant resistor with the next smallest resistance value and the resistance value of the constant resistor with the smallest resistance value.

[0020] In this regard, it is particularly preferred that, except for the constant resistor with the smallest resistance value, the resistance value of any constant resistor is at least twice the resistance value of the constant resistor with the next smallest resistance value. This means that the greater the resistance value itself, the greater the difference between the resistance values. In this regard, a preferred design is that the resistance values ​​of the constant resistors follow the provisions of a divergent geometric series. Here, for example, in the case of n constant resistors, the resistance value calculation is achieved by means of the following equation:

[0021]

[0022] in,

[0023] R1 is the resistance value of the constant resistor with the minimum resistance value,

[0024] R n is the resistance value of the constant resistor with the maximum resistance value, and

[0025] q is any value greater than 1.

[0026] In this context, it is particularly preferred if q is greater than or equal to 2.

[0027] Furthermore, the present invention also relates to a circuit board for installation in a charging connector for an electric vehicle or a hybrid vehicle, the circuit board having the circuit arrangement as described above.

[0028] According to a preferred improvement of the invention, the circuit board is designed in this case so that the temperature-dependent resistors are arranged at thermal contact locations of the circuit board for thermal contact with the corresponding charging contacts of the charging plug, and the thermal contact locations are provided with thermal contact elements, which are in direct thermal contact with the respective temperature-dependent resistors and can be in physical contact with the charging contacts. A circuit board of this type can be arranged in the charging plug in such a way that the circuit board is, so to speak, located "between" the charging contacts and is now in direct thermal contact with the charging contacts using the thermal contact elements of the circuit board. In this way, the thermal contact elements are essentially in thermal equilibrium with the charging contacts, so that the temperature-dependent resistors can detect the temperature existing on the corresponding charging contacts almost in real time.

[0029] In this regard, it is particularly preferred that the thermal contact point is formed by a notch in the circuit board, preferably by a partially circular notch. This type of semicircular notch can directly abut against the circular charging contact and thus ensure very good heat transfer.

[0030] The present invention also relates to a charging connector for an electric vehicle or a hybrid vehicle, the charging connector having a circuit device as described above or a circuit board as described above. It is particularly preferred that the temperature-dependent resistor is arranged in such a way that the corresponding temperature of the AC charging contact can be detected using the temperature-dependent resistor. That is, more than two AC contacts are often provided in this type of charging connector, so that the current temperature can be detected individually on each AC charging contact in an efficient manner using the circuit device described above. The charging connector is preferably a built-in charging plug that can be installed in the body of the electric vehicle or hybrid vehicle. For example, the charging connector is a built-in charging plug according to the European standard IEC62196 type 2 or according to the American standard SAEJ1772. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention will be described in more detail below based on preferred embodiments with reference to the accompanying drawings.

[0032] in:

[0033] Figure 1 Schematically shows a circuit arrangement according to a first preferred embodiment of the present invention,

[0034] Figure 2 Shown in accordance with Figure 1 The temperature-dependent resistance behavior of the PTC element as a temperature-dependent resistor in a circuit arrangement of

[0035] Figure 3 Shown in use Figure 1 In the case of a circuit arrangement in FIG. 1 , the different AC charging contacts of the charging connector are Figure 1The temperature-dependent profile of the measured voltage in the circuit arrangement shown in FIG.

[0036] Figure 4 shows a Figure 1 The charging connector of the circuit board of the circuit arrangement shown in FIG.

[0037] Figure 5a schematically shows a circuit arrangement according to a second preferred embodiment of the present invention, and

[0038] Figure 5b Shown in detail Figure 5a A single circuit of a circuit device. DETAILED DESCRIPTION

[0039] Figure 1 The circuit device 1 according to a preferred embodiment of the present invention is schematically shown. Figure 1 Shown in FIG. 1 are charging contacts 2 for a charging connector of an electric vehicle or hybrid vehicle, the respective temperature of which is to be monitored.

[0040] The circuit arrangement 1 according to the preferred exemplary embodiment of the invention described herein has a temperature-dependent resistor 4 and a constant resistor 5. In this case, the temperature-dependent resistor 4 is connected in series with the constant resistor 5. The explanation of the preferred exemplary embodiment of the invention described here is based on the partial description in Figure 4 The charging plug 3 shown in the figure is in the form of a built-in charging plug that can be installed in the body of an electric vehicle or a hybrid vehicle according to the European standard IEC62196 type 2. Figure 1 The charging contacts 2 shown in the figure are AC contacts of a built-in charging plug 3, which are marked as L1, L2, L3 and N according to the standard in this document. Therefore, there are four charging contacts 2 whose respective temperatures should be monitored in this document. Therefore, four resistor pairs are also provided, each consisting of a corresponding temperature-dependent resistor 4 and a corresponding constant resistor 5, and the temperature-dependent resistors and the constant resistors are connected in series with each other. These four series circuits are connected in parallel with each other, wherein a voltage measuring device 6 is provided, by which the voltage drop on the parallel circuit can be determined.

[0041] Now, an important aspect is that the temperature-dependent resistors 4 are all designed as PTC elements of the same type, ie all exhibit the same temperature-dependent resistance behavior. In contrast, the constant resistors are all different from one another, in that all have different resistance values.

[0042] Here, the constant resistor 5 has different resistance values, that is, these resistance values ​​follow the law of divergent geometric series. Specifically, the resistance values ​​are 200Ω, 400Ω, 800Ω and 1600Ω. In this way, the resistance values ​​of the constant resistor 5 will not be too close to each other, so that the following problem cannot be shown: due to the temperature dependence of the temperature-dependent resistor 4, the resistance value of the corresponding series circuit has basically fluctuated with the temperature before reaching the triggering threshold of the corresponding PTC element.

[0043] With regard to the temperature-dependent resistance behavior and the triggering threshold of the PTC element configured as a temperature-dependent resistor 4, reference should be made to Figure 2 .exist Figure 2 , how the resistance of currently used PTC elements changes as a function of temperature. It can be seen that in the temperature range of -40°C to 90°C, the resistance of the PTC element is in the range between 618Ω and 1350Ω. Above 90°C, the resistance of the PTC element increases significantly, so that at 100°C resistance values ​​of approximately 10,000Ω are already present. The triggering threshold is therefore here in the range above 1350 ohms.

[0044] Therefore, we get Figure 1 The resistance behavior of the parallel circuit of a resistor pair formed by a temperature-dependent resistor 4 and a constant resistor 5 is shown in FIG. Mess The measurement voltage itself is detected by means of a voltage measuring device 6. Figure 3 The resistance behavior is shown in FIG.

[0045] Figure 3 In its upper region, the temperature is shown, which, according to the standard in this document, is first applied to the charging contact 2 marked with PE and then to the charging contacts L1, L2 and L3. Since there is no temperature-dependent resistor and no constant resistor at the charging contact marked with PE, the temperature dependence does not lead to a voltage change detected by means of the voltage measuring device 6 here. However, the charging contacts 2 marked with N, L1, L2 and L3 are each provided with a resistor pair formed by a temperature-dependent resistor 4 and a constant resistor 5. Since at Figure 2 The temperature-dependent resistance characteristic of the temperature-dependent resistor 4 shown in FIG. Figure 1 The total resistance of the circuit arrangement 1 shown here varies, which results in Figure 3 The voltage variation curve shown in .

[0046] From the perspective of shape, when the temperature rises, the different voltage change curves on the charging contacts 2 marked with N, L1, L2 and L3 are essentially the same. However, due to the different resistance values ​​of the various constant resistors 5, voltages with different values ​​are obtained in the process of reaching the trigger threshold of each PTC element. Specifically, in the charging contact 2 marked with N, the trigger threshold is reached when the voltage measuring device 6 measures a value of approximately 6V. For the voltage contacts 2 marked with L1, L2 and L3, this voltage value gradually increases to approximately 6.4V, 6.8V and 7.2V. In this way, each resistance path assigned to the corresponding charging contact 2 is "encoded" to a certain extent, because the total resistance of the circuit device 1 obtained (which itself can be measured according to the measured voltage U Mess Determination) can identify to which charging contact 2 the change in the total resistance of the circuit arrangement 1 is attributed the temperature increase.

[0047] In addition, refer again Figure 4 , Figure 4 A partial view of a built-in charging plug 1 according to European standard IEC 62196 type 2 is shown. Figure 4 As can be seen, a circuit board 7 is actually embedded "between" the charging contacts 2 of the built-in charging plug 3, on which a temperature-dependent resistor 4 is arranged. For the sake of clarity, the constant resistor 5 is not shown here. The temperature-dependent resistor is connected to a thermal contact element 8, which is located in a corresponding partially circular notch 10 of the circuit board 7. Therefore, the thermal contact element 8 directly contacts the corresponding charging contact 2, so that a very good heat exchange can be achieved between the corresponding charging contact 2 and the corresponding temperature-dependent resistor 4. In this way, the corresponding temperature of the charging contact 2 can be determined almost in real time via the temperature-dependent resistor 4. By additionally providing Figure 1 The circuit arrangement 1 shown in FIG. 1 (which is shown in FIG. 1 for the sake of clarity) Figure 4 (also not shown), it is possible to determine exactly at which charging contact 2 the measuring voltage U measured by the voltage measuring device 6 occurs, as described above. Mess The temperature at which the change occurs increases.

[0048] Now, Figure 5a A circuit arrangement according to a second preferred embodiment of the present invention is schematically shown. Here, four circuits 11 are connected in parallel, wherein the construction of a single circuit 11 is schematically shown in FIG. Figure 5b It shows:

[0049] Each circuit 11 has a transistor 8, wherein a temperature-dependent resistor 4 is respectively connected to the base of the corresponding transistor 8. In addition, a constant resistor 5 is respectively connected in series with the transistor 8 via two other connections of the transistor. The constant resistors 5 all have different fixed resistance values, and each constant resistor 5 is connected to the corresponding temperature-dependent resistor 4 via its end remote from the respective transistor 8 via a corresponding auxiliary constant resistor 12.

[0050] Now, the second preferred embodiment of the invention provides two options: If the temperature-dependent resistor 4 is a PTC element, then when a predefined temperature limit is reached on the charging contact, the resistance of the PTC element increases, which causes a voltage drop at the transistor base, so that the transistor 8 is blocked. However, if an NTC element is used, it is applicable that when the temperature limit is reached on the charging contact, the resistance of the NTC element decreases, which causes a voltage increase at the transistor base, so that the transistor 8 is turned on. Thus, the corresponding electrical path can be "switched on" or "cut off" to a certain extent by means of the corresponding transistor 8, so that the charging contact that has exceeded the temperature limit can be inferred by a corresponding change in the total resistance of the circuit arrangement.

[0051] List of reference numerals:

[0052] 1 Circuit Device

[0053] 2 Charging contacts

[0054] 3 Charging connector / built-in charging plug

[0055] 4 Temperature-dependent resistance

[0056] 5 Constant resistance

[0057] 6 Voltage measuring device

[0058] 7 Circuit Board

[0059] 8 Thermal contact elements

[0060] 9 Transistors

[0061] 10 Gap

[0062] 11 Circuit

[0063] 12 Auxiliary constant resistance

Claims

1. A circuit device (1) for monitoring the respective temperatures of a plurality of charging contacts (2) of a charging plug connector (3) for an electric vehicle or a hybrid vehicle, the circuit device comprising: A plurality of temperature-dependent resistors (4), each of which is assigned to each charging contact (2) and can be thermally coupled to the corresponding charging contact. A plurality of constant resistors (5), each of which has a constant resistance value, in, Each temperature-dependent resistor (4) is connected to one of the constant resistors (5), A parallel circuit is provided in which circuits formed by a respective temperature-dependent resistor (4) and a respective constant resistor (5) are connected in parallel with each other, The constant resistors (5) all have resistance values ​​different from each other, A voltage measuring device (6) is provided, by means of which the voltage drop across the parallel circuit can be determined.

2. The circuit arrangement (1) according to claim 1, characterized in that Each temperature-dependent resistor (4) is connected in series with one of the constant resistors (5). In the provided parallel circuit, series circuits formed by a respective temperature-dependent resistor (4) and a respective constant resistor (5) are connected in parallel with each other.

3. The circuit arrangement (1) according to claim 1, further comprising a plurality of transistors (8), A circuit is provided in which a respective temperature-dependent resistor (4) is connected to the base of a respective transistor (8), and a constant resistor is connected in series with the transistor (8) through two other connections of the respective transistor. In the parallel circuit provided, the circuits (11) each formed by a constant resistor (5), a respective transistor (8) and a respective temperature-dependent resistor (4) are connected in parallel with one another.

4. The circuit arrangement (1) according to claim 1, characterized in that The temperature-dependent resistors (4) are all of the same type and have the same temperature dependency.

5. The circuit arrangement (1) according to any one of the preceding claims, characterized in that The resistance value of the constant resistor (5) having the next smallest resistance value is at least twice the resistance value of the constant resistor (5) having the smallest resistance value.

6. The circuit arrangement (1) according to claim 5, characterized in that The respective differences between the resistance values ​​of all constant resistors (5) are at least equivalent to the difference between the resistance value of the constant resistor (5) having the next smallest resistance value and the resistance value of the constant resistor (5) having the smallest resistance value.

7. The circuit arrangement (1) according to claim 5 or 6, characterized in that Except for the constant resistor (5) having the smallest resistance value, the resistance value of each constant resistor (5) is at least twice the resistance value of the constant resistor (5) having the next smallest resistance value.

8. The circuit arrangement (1) according to any one of claims 5 to 7, characterized in that The resistance value of the constant resistor (5) follows the rule of a divergent geometric series.

9. The circuit arrangement (1) according to claim 8, characterized in that For the constant resistor (5) with resistance values ​​R1,...,R n , satisfying the following formula: in, R1 is the resistance value of the constant resistor (5) with the minimum resistance value, R n is the resistance value of the constant resistor (5) having the maximum resistance value, q is any value greater than 1.

10. A circuit board (7) for installation in a charging connector (3) for an electric vehicle or a hybrid vehicle, the circuit board having a circuit arrangement (1) according to any one of the preceding claims.

11. The circuit board (7) according to claim 10, characterized in that: The temperature-dependent resistor (4) is arranged at a thermal contact position of the circuit board (7) for thermal contact with the corresponding charging contact (2) of the charging connector (3), and the thermal contact position is provided with a thermal contact element (8), which is in direct thermal contact with the corresponding temperature-dependent resistor (4) and can be in physical contact with the charging contact (2) through the thermal contact element.

12. The circuit board (7) according to claim 11, characterized in that: The thermal contact point is formed by a recess (10) in the printed circuit board (7).

13. A charging plug (3) for an electric vehicle or a hybrid vehicle, comprising a circuit arrangement (1) according to any one of claims 1 to 10 or a printed circuit board (7) according to claim 12 or 13.

14. The charging connector (3) according to claim 13, characterized in that: The temperature-dependent resistor (4) is arranged in such a way that the corresponding temperature of the AC charging contact (2) can be detected by means of the temperature-dependent resistor.

15. The charging connector according to claim 13 or 14, characterized in that: The charging connector (3) is designed as a built-in charging plug which can be installed in the body of an electric vehicle or a hybrid vehicle.

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