An electrical circuit for monitoring corresponding temperatures of a plurality of charging contacts of a charging plug connector

Abstract

The present invention relates to an electrical circuit (1) for monitoring the corresponding temperatures of a plurality of charging contacts (2) of a charging plug connector (3) for an electric or hybrid vehicle, the electrical circuit (1) comprising a plurality of temperature-based resistors (4), each paired with a charging contact (2) and capable of being thermally coupled to the charging contact (2), and a plurality of constant resistors (5), each having a constant resistance, wherein each of the temperature-based resistors (4) is connected in series with one of the constant resistors (5) to provide a parallel circuit, wherein series circuits consisting of a corresponding temperature-based resistor (4) and a corresponding constant resistor (5) are connected in parallel with each other according to the parallel circuit, all of the constant resistors (5) having different resistances, and a voltage measuring device (6) by which a voltage drop across the parallel circuit can be determined. Thus, the present invention enables a simple and reliable method for determining which of a plurality of charging contacts of a charging plug connector for an electric or hybrid vehicle exhibits critical heating during operation.

Description

[Technical Field]

[0001]

[0001] The present invention relates to an electrical circuit for monitoring the corresponding temperatures of a plurality of charging contacts of a charging plug connector for an electric or hybrid vehicle, the electrical circuit comprising a plurality of temperature-based resistors, each paired with a charging contact and capable of being thermally coupled to the charging contact.

[0002] Electric and hybrid vehicles have a rechargeable energy storage device, typically a high-voltage battery, that supplies energy to the electric drive motor during driving. Because these high-voltage batteries have limited storage capacity, they must be periodically recharged at a charging station. The battery is charged via a charging cable installed between the charging station and the vehicle. For example, according to European Standard IEC 62196 Type 2, one side of the charging cable is provided with a charging plug that can be inserted into a charging socket installed at the charging station, and the other side is provided with a charging coupler that can be connected to an internal charging plug installed in the electric or hybrid vehicle. In this case, the charging socket, charging plug, charging coupler, and internal charging plug are all encompassed by the term "charging plug connector." The charging socket and charging coupler have contact sleeves as charging contacts, and the charging plug, as well as the internal charging plug that can be installed in the electric or hybrid vehicle, have contact pins as charging contacts that can be inserted into the contact sleeves.

[0003]

[0003] Charging plug connectors for electric and hybrid vehicles are subject to legal and user-specific requirements for temperature monitoring of AC and DC charging contacts. For DC charging, temperature measurement is typically required on both DC charging contacts. For this purpose, a component suitable for temperature measurement, typically an NTC resistor, is placed as close as possible to the heat source, i.e., the charging contacts, to enable real-time temperature monitoring for charging optimization and safety monitoring. NTC resistors are resistors used in electronic components. NTC resistors are also called thermistors or hot conductors. The abbreviation "NTC" stands for "negative temperature coefficient" and describes the property of a thermistor to have a negative temperature coefficient and therefore conduct electricity better as the temperature increases.

[0004]

[0004] AC charging typically requires either NTC temperature measurement or the simpler PTC temperature monitoring. PTC resistors, also known as thermistors or PTC thermistors ("positive temperature coefficient"), are also temperature-based resistors, but PTC resistors conduct current better at low temperatures than at high temperatures.

[0005]

[0005] The difference between using PTC elements and NTC elements is that while NTC elements allow for actual temperature measurement, PTC elements usually have a non-linear resistance behavior above a threshold temperature and can therefore be used to send a signal when a critical temperature is exceeded. PTC elements can therefore be used to achieve a kind of "safety" by returning a rapidly changing value to a reading system when a critical temperature is exceeded.

[0006] Depending on the standard and manufacturer specifications, actual temperature measurement or only detection of exceeding a temperature threshold is required for all AC charging contacts (e.g., L1, L2, L3 and N in the case of a connector according to European standard IEC 62196 Type 2), which may be required for each AC charging contact separately or collectively, i.e., for all AC charging contacts together.

[0007] German Patent Application Publication No. 102015106251 describes a temperature monitoring device with a carrier element extending flat along a plane and having openings. The carrier element can be designed as a circuit board. The contact elements are components of a contact assembly that can be attached to a plug insert as a modular unit. The contact assembly includes a temperature monitoring device with a carrier element. The temperature monitoring device serves to detect unacceptable heating at least on contact elements used to transmit high currents during operation of the plug connector part. For the necessary contact, the carrier element has a metal coating at each opening to provide a contact surface in the form of a through-hole. A sensor device 432 is arranged on the coupling part, which conducts heat from the contact elements to the sensor device. Conductor tracks lead from the sensor device to a higher-level control device. A sensor signal generated by the sensor device can be evaluated in the control device to control the current flowing through the contact element in response to the sensor signal. A sensor device can be provided for each contact element to be monitored, so that the temperature at each contact element to be monitored can be monitored individually and heating can be detected.

[0008]

[0008] WO 2021 / 004765 describes an electrical assembly with a temperature monitoring device. Described is a plug connector part having both AC and DC charging contacts. In particular, to monitor possible heating at the DC charging contacts, the plug connector part has an electrical assembly. The assembly consists of contact elements arranged on a carrier element and electrically connected to a pair of load wires. Each contact element is received in a pair of receiving openings in the carrier element. The temperature monitoring device has a temperature sensor. The temperature monitoring device is fixed to a surface of the carrier element. Heat from the contact elements is conducted to the temperature monitoring device.

[0009]

[0009] Based on this, the object of the present invention is a simple and reliable method for determining which of multiple charging contacts of a charging plug connector for an electric or hybrid vehicle exhibits critical heating during operation.

[0010]

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

[0011]

[0011] According to the present invention, there is provided an electrical circuit for monitoring corresponding temperatures of a plurality of charging contacts of a charging plug connector for an electric or hybrid vehicle, the electrical circuit comprising a plurality of temperature-based resistors, each paired with a charging contact and capable of being thermally coupled to the charging contact, and a plurality of constant resistors, each having a constant resistance, wherein each of the temperature-based resistors is connected to one of the constant resistors, a parallel circuit is provided, according to which interconnections consisting of corresponding temperature-based resistors and corresponding constant resistors are connected in parallel with each other, all of the constant resistors have different resistances, and a voltage measuring device is provided, by which the voltage drop across the parallel circuit can be determined.

[0012]

[0012] According to a preferred development of the invention, the electrical circuit is implemented so that it is provided with a plurality of temperature-based resistors, each paired with a charging contact and capable of being thermally coupled to the charging contact, and a plurality of constant resistors, each having a constant resistance, wherein each of the temperature-based resistors is connected in series with one of the constant resistors, a parallel circuit is provided, according to which series circuits consisting of a corresponding temperature-based resistor and a corresponding constant resistor are connected in parallel with each other, all of the constant resistors have different resistances, and a voltage measuring device is provided, by means of which the voltage drop across the parallel circuit can be determined.

[0013]

[0013] Thus, a substantial aspect of this embodiment is that an electrical path is "coded" through a corresponding temperature-based resistor, i.e., a constant resistor whose resistance is different from the resistance of all other constant resistors placed in the path of the other temperature-based resistors. For each charging contact whose temperature is to be monitored, there is a series circuit of a temperature-based resistor and a constant resistor, the temperature-based resistor intended to detect the temperature of the corresponding charging contact. These series circuits are connected in parallel with each other, so that the total resistance of this parallel circuit changes individually depending on which of the temperature-based resistors exhibits an increase in resistance due to the charging contact to which the temperature-based resistor is assigned heating up above a critical temperature.

[0014]

[0014] An alternative implementation form of the present invention is carried out according to a preferred development of the present invention, in which the electrical circuit according to the present invention further comprises a plurality of transistors, and such interconnections are provided, according to which a temperature-based resistor is connected to the base of a corresponding transistor, and a constant resistor is connected in series with the corresponding transistor via two other terminals, and a parallel circuit is provided, according to which interconnections each consisting of a constant resistor, a transistor and a temperature-based resistor are connected in parallel with each other.

[0015] According to this preferred embodiment of the present invention, a transistor is used for each charging contact, and the corresponding base of the transistor is pre-controlled via a circuit having a temperature-based resistor. The temperature-based resistor is preferably a PTC or NTC element. If the temperature-based resistor is a PTC element, the PTC element becomes highly resistant when a predetermined limit temperature is reached at the charging contact, which causes a voltage drop at the transistor base, thereby blocking the transistor. If an NTC element is used, the NTC element becomes less resistant when a limit temperature is reached at the charging contact, which causes a voltage rise at the transistor base, switching the transistor on. The "encoding" of the electrical path is achieved here by the transistor "switching on" or "switching off" a constant resistance of the corresponding electrical path.

[0016]

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

[0017]

[0017] Preferably, all the temperature-based resistors are of the same type and exhibit the same dependence of their resistance on temperature. In this preferred embodiment of the invention, it is advantageous not to ensure that the corresponding resistances of the temperature-based resistors and the constant resistors always match each other so that the individual resistances are achieved overall, which allows the ability according to the invention to draw conclusions about the temperature-based resistors located at the charging contacts whose temperature has exceeded a critical temperature from the total resistance of the parallel circuit.

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

[0019]

[0019] The present invention initially requires only that all of the constant resistors have different resistances. However, temperature-based detection of a critical temperature rise through the total resistance of the parallel circuit works particularly reliably if the resistance of the constant resistor with the second lowest resistance is at least twice as high as the resistance of the constant resistor with the lowest resistance. Preferably, the corresponding difference between the resistances of all constant resistors corresponds to at least the difference between the resistance of the constant resistor with the second lowest resistance and the resistance of the constant resistor with the lowest resistance. In other words, this means that the difference in resistance between any two constant resistors is at least as large as the difference between the resistance of the constant resistor with the second lowest resistance and the resistance of the constant resistor with the lowest resistance.

[0020]

[0020] In this context, it is very particularly preferred that the resistance of each constant resistor, except for the constant resistor with the lowest resistance, is at least twice the resistance of the constant resistor with the next lowest resistance. This means that the greater the resistance itself, the greater the difference between their resistances. A preferred embodiment in this context is that the resistances of the constant resistors obey the law of a diverging geometric progression. The calculation of the resistance for n constant resistors can be carried out, for example, using the following formula:

number

[0021] In this context, it is very particularly preferred that q is 2 or greater.

[0022] The present invention further relates to an electrical circuit board for installation in a charging plug connector for an electric or hybrid vehicle, having the electrical circuit described above.

[0023]

[0023] According to a preferred embodiment of the present invention, the electrical circuit board is designed so that the temperature-based resistors are arranged at thermal contact points of the electrical circuit board for thermally contacting the corresponding charging contacts of the charging plug connector, and the thermal contact points are provided with thermal contact elements that are in direct thermal contact with the corresponding temperature-based resistors and that can bring the charging contacts into physical contact. Such an electrical circuit board can be arranged in the charging plug connector so that it is located "between" the charging contacts, so to speak, and its thermal contact elements are in direct thermal contact with the charging contacts. In this way, the thermal contact elements are substantially in thermal equilibrium with the charging contacts, allowing the temperature-based resistors to detect the temperature prevailing at the corresponding charging contacts in almost real time.

[0024]

[0024] In this context, it is very particularly preferred that the thermal contact points are formed by recesses in the electrical circuit board, preferably by part-circular recesses, which are in direct contact with the circular charging contacts and can therefore ensure very good heat transfer.

[0025]

[0025] The present invention further relates to a charging plug connector for an electric or hybrid vehicle having the above-described electrical circuit or the above-described electrical circuit board. It is very particularly preferred that the temperature-based resistor be configured so that it can be used to detect the corresponding temperature of the AC charging contacts. Often, three or more AC contacts are provided in such a charging plug connector, so that the current temperature can be detected individually and efficiently at each AC charging contact using the above-described electrical circuit. The charging plug connector is preferably an internal charging plug that can be installed in the body of the electric or hybrid vehicle. For example, it is an internal charging plug conforming to European standard IEC 62196 Type 2 or American standard SAE J1772.

[0026]

[0026] The invention is explained in more detail below on the basis of preferred exemplary embodiments and with reference to the drawings. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is a diagram illustrating a schematic diagram of an electric circuit according to a first preferred exemplary embodiment of the present invention; [Figure 2] FIG. 2 shows the temperature-based resistance behavior of a PTC element as a temperature-based resistor in the circuit described in FIG. 1. [Figure 3] 2A-2C show temperature-based curves of measured voltage in the circuit shown in FIG. 1 for various AC charging contacts of a charging plug connector when using the circuit of FIG. 1. [Figure 4] 2 is a diagram showing a charging plug connector having an electric circuit board that supports the electric circuit shown in FIG. 1. [Figure 5a] FIG. 2 is a schematic diagram of an electric circuit according to a second preferred exemplary embodiment of the present invention; [Figure 5b] FIG. 5b shows in detail the individual interconnections of the electrical circuit of FIG. 5a. DETAILED DESCRIPTION OF THE INVENTION

[0028]

[0028] Figure 1 shows a schematic diagram of an electric circuit 1 according to a preferred exemplary embodiment of the present invention. Charging contacts 2 of a charging plug connector for an electric or hybrid vehicle, the corresponding temperatures of which should be monitored, are not part of the electric circuit 1 but are already shown in Figure 1.

[0029]

[0029] An electric circuit 1 according to a preferred exemplary embodiment of the present invention described herein includes a temperature-based resistor 4 and a constant resistor 5. The temperature-based resistor 4 is connected in series with the constant resistor 5. The description of the preferred exemplary embodiment of the present invention described herein is based on a charging plug connector 3 shown in detail in FIG. 4 in the form of an internal charging plug that can be installed in the body of an electric or hybrid vehicle in accordance with European Standard IEC 62196 Type 2. The charging contacts 2 shown in FIG. 1 are AC contacts of the internal charging plug 3, designated L1, L2, L3, and N according to this standard. At this point, there are four charging contacts 2 whose corresponding temperatures should be monitored. Therefore, four pairs of temperature-based resistors 4 and constant resistors 5 are provided, each connected in series with the other. These four series circuits are connected in parallel, and a voltage measuring device 6 is provided, by which the voltage drop across the parallel circuit can be determined.

[0030] An important aspect is that the temperature-based resistors 4 are all made from the same type of PTC element, i.e., they all exhibit the same temperature-based resistance behavior. In contrast, the constant resistors are all different from one another in that they all have different resistances.

[0031] In this case, the constant resistors have five different resistances that follow the law of a diverging geometric progression. Specifically, the resistances are 200 Ω, 400 Ω, 800 Ω, and 1600 Ω. In this way, the resistances of the constant resistors 5 are not too close to each other, so that it does not matter that the resistance of the corresponding series circuit, due to the temperature dependence of the temperature-based resistor 4, is already varying with temperature before the trigger threshold of the corresponding PTC element is reached.

[0032]

[0032] With regard to the temperature-based resistance behavior and trigger threshold of the PTC element provided as the temperature-based resistor 4, reference is made to Figure 2. Figure 2 shows how the resistance of the PTC element used here varies with temperature. It can be seen that the resistance of the PTC element in the temperature range from -40°C to 90°C is 618 to 1350 ohms. Above 90°C, the resistance of the PTC element increases sharply, so that at 100°C there is already a resistance of approximately 10,000 ohms. The trigger threshold here is therefore in the range above 1350 ohms.

[0033] This results in the resistance behavior of the parallel circuit shown in FIG. 1 of the corresponding pair of temperature-based resistor 4 and constant resistor 5, which is related to the measured voltage U detected by the voltage measuring device 6. Mess The resistance behavior is shown in Figure 3.

[0034]

[0034] Figure 3 shows in its upper region the temperature applied first to charging contact 2 designated PE according to this standard, and then to charging contacts N1, L1, L2 and L3. Since there is no temperature-based or constant resistance at the charging contact designated PE, the temperature dependence does not result in any change in the voltage detected by voltage measuring device 6. However, charging contacts 2 designated N, L1, L2 and L3 are each provided with a pair formed by temperature-based resistor 4 and constant resistor 5. The temperature-based resistance characteristic of temperature-based resistor 4 shown in Figure 2 results in the curve of the total resistance of electrical circuit 1 shown in Figure 1, which in turn results in the voltage curve shown in Figure 3.

[0035] In terms of shape, the various voltage curves at the charging contacts 2 designated N, L1, L2, and L3 are all qualitatively the same as the temperature increases. However, the different resistances of the corresponding constant resistors 5 result in qualitatively different voltages on the way to the trigger threshold of the corresponding PTC element. Specifically, the trigger threshold is reached for the charging contact 2 designated N when the voltage measuring device 6 measures a value of approximately 6 V. This voltage value increases successively to approximately 6.4 V, 6.8 V, and 7.2 V for the voltage contacts 2 having the designations L1, L2, and L3. In this way, each resistance path paired with the corresponding charging contact 2 is effectively "coded," which means that the measured voltage U can be used to determine which charging contact 2 has experienced a temperature increase that causes a change in the total resistance of the electrical circuit 1. Mess This is because the resulting total resistance of circuit 1 based on

[0036]

[0036] Furthermore, referring again to Figure 4, Figure 4 shows in detail the built-in charging plug 1 according to European standard IEC 62196 Type 2. From Figure 4, it can be seen that the electrical circuit board 7 on which the temperature-based resistors 4 are arranged is inserted substantially "between" the charging contacts 2 of the built-in charging plug 3. For clarity, the constant resistors 5 are not shown here. The temperature-based resistors are coupled to thermal contact elements 8 in corresponding partial circular cutouts 10 of the circuit board 7. These thermal contact elements 8 are therefore in direct contact with the corresponding charging contacts 2, thereby achieving very good heat exchange between the corresponding charging contacts 2 and the corresponding temperature-based resistors 4. In this way, the corresponding temperatures of the charging contacts 2 can be determined in almost real time using the temperature-based resistors 4. By further providing the electrical circuit 1 shown in Figure 1, which is also not shown in Figure 4 for clarity, the measured voltage U measured by the voltage measuring device 6, as described above, can be determined. Mess It can be determined exactly at which charging contact 2 the temperature rise that caused the change in temperature occurred.

[0037]

[0037] Next, Figure 5a shows a schematic diagram of an electric circuit according to a second preferred exemplary embodiment of the present invention, in which four interconnects 11 are connected in parallel, and each interconnect 11 is configured as shown schematically in Figure 5b.

[0038] Each interconnect 11 has a transistor 8, and a temperature-based resistor 4 is connected to the base of the corresponding transistor 8. Furthermore, a constant resistor 5 is connected in series with the transistor 8 via the other two terminals. All of the constant resistors 5 have different fixed resistances, and each constant resistor 5 is connected to the corresponding temperature-based resistor 4 at the end opposite the corresponding transistor 8 via a corresponding auxiliary constant resistor 12.

[0039]

[0039] Next, the second preferred exemplary embodiment of the present invention provides two options: if the temperature-based resistors 4 are each PTC elements, the PTC elements will become high resistance when a predetermined limit temperature is reached at the charging contact, which causes a voltage drop at the transistor base, thereby blocking the transistor 8. However, if an NTC element is used, the NTC element will become low resistance when a limit temperature is reached at the charging contact, which causes a voltage rise at the transistor base, switching on the transistor 8. This allows the corresponding electrical path to be effectively "switched on" or "switched off" by the corresponding transistor 8, so that the corresponding change in the total resistance of the electrical circuit can be used to determine which charging contact has exceeded its limit temperature. [Explanation of symbols]

[0040] 1 Electrical Circuits 2 charging contacts 3 Charging plug connector / built-in charging plug 4 Temperature-Based Resistors 5 Constant resistor 6. Voltage measuring device 7 Electrical circuit board 8 Thermal Contact Elements 9. Transistors 10 recess 11 Interconnection 12 Auxiliary constant resistor

Claims

1. An electrical circuit (1) for monitoring corresponding temperatures of a plurality of charging contacts (2) of a charging plug connector (3) for an electric or hybrid vehicle, comprising: a plurality of temperature-based resistors (4), each paired with a charging contact (2) and capable of being thermally coupled to said charging contact (2); a plurality of constant resistors (5), each having a constant resistance; Each temperature-based resistor (4) is connected to one of said constant resistors (5); a parallel circuit is provided, according to which interconnections consisting of corresponding temperature-based resistors (4) and corresponding constant resistors (5) are connected in parallel with each other; All of said constant resistors (5) have different resistances, An electric circuit (1) provided with a voltage measuring device (6) by means of which the voltage drop across the parallel circuit can be determined.

2. Each of the temperature-based resistors (4) is connected in series with one of the constant resistors (5); a parallel circuit is provided, according to which series circuits of corresponding temperature-based resistors (4) and corresponding constant resistors (5) are connected in parallel with each other; An electric circuit (1) according to claim 1.

3. Further comprising a plurality of transistors (8), The interconnection (11) is provided, and according to the interconnection (11), the temperature-based resistor (4) is connected to the base of the corresponding transistor (8), and the constant resistor (5) is connected in series with the corresponding transistor (8) through two other terminals; 2. The electric circuit (1) according to claim 1, wherein a parallel circuit is provided, according to which the interconnects (11) each consisting of a constant resistor (5), a transistor (8) and a temperature-based resistor (4) are connected in parallel with each other.

4. The electric circuit (1) according to any one of claims 1 to 3, wherein the temperature-based resistors (4) are all of the same type and the temperature-dependence of the resistance of the temperature-based resistors (4) is the same.

5. 5. The electric circuit (1) according to any one of claims 1 to 4, wherein the resistance of the constant resistor (5) having the second lowest resistance is at least twice as high as the resistance of the constant resistor (5) having the lowest resistance.

6. 6. The electric circuit (1) according to claim 5, wherein the corresponding difference between the resistances of all the constant resistors (5) corresponds at least to the difference between the resistance of the constant resistor (5) having the second lowest resistance and the resistance of the constant resistor (5) having the lowest resistance.

7. 7. The electric circuit (1) according to claim 5 or 6, wherein the resistance of each constant resistor (5), except for the constant resistor (5) having the lowest resistance, is at least twice the resistance of the constant resistor (5) having the next lowest resistance.

8. The electric circuit (1) according to any one of claims 5 to 7, wherein the resistance of the constant resistor (5) obeys the law of a diverging geometric progression.

9. The resistance R of the constant resistor (5) １ ,... ,R ｎ For [Equation 1] is applied, R １ constitutes the resistance of the constant resistor (5) having the lowest resistance, R ｎ constitutes the resistance of the constant resistor (5) having the highest resistance, 9. The electric circuit (1) according to claim 8, wherein q is any value greater than 1.

10. An electric circuit board (7) for installation in a charging plug connector (3) for an electric or hybrid vehicle, comprising an electric circuit (1) according to any one of claims 1 to 9.

11. 11. The electric circuit board (7) of claim 10, wherein a temperature-based resistor (4) is disposed at a thermal contact point of the electric circuit board (7) for thermally contacting a corresponding charging contact (2) of the charging plug connector (3), and the thermal contact point is provided with a thermal contact element (8) that is in direct thermal contact with the corresponding temperature-based resistor (4) and can bring the charging contact (2) into physical contact.

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

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

14. 14. The charging plug connector (3) of claim 13, wherein the temperature-based resistor (4) is configured to be used to detect a corresponding temperature of the AC charging contacts (2).

15. Charging plug connector (3) according to claim 13 or 14, wherein the charging plug connector (3) is designed as an internal charging plug that can be installed in the body of an electric or hybrid vehicle.

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