Method for determining a temperature of a pin; and connector for power transmission

Abstract

The present disclosure relates to a method for determining the temperature of a pin (1) on a connector for power transmission, in particular a charging connector (2) for an electric vehicle. Furthermore, the present disclosure relates to a connector for power transmission, in particular a charging connector (2) for an electric vehicle, comprising at least one pin (1), a temperature sensor (4) spaced apart from the pin (1), and a control unit (3), preferably integrated in the charging connector (2), which is configured to carry out the disclosed method.

Description

[0001] The disclosure relates to a method for determining a temperature of a pin or current contact on a connector for power transmission, in particular on a charging connector for an electric vehicle.

[0002] Common electric vehicles typically have an electrical energy storage device, such as a battery, that provides the electrical energy for the drive. If this electrical energy storage device is fully or partially discharged, the electric vehicle's energy storage device must be connected to the power grid at a charging point and recharged. There are essentially two options for charging electric vehicles. For example, electric vehicles can be charged at publicly accessible charging columns or charging stations or at home using a standard electrical outlet.

[0003] The first option allows charging at permanently installed charging stations (charging columns or so-called wall boxes). For this purpose, a charging cable is plugged into the charging station. Alternatively, the charging cable can already be permanently connected to the charging station. Such a charging cable is also called a passive charging cable and is used to conduct the power from the charging station to the energy storage unit located in the vehicle. The second option allows the electric vehicle's energy storage unit to be charged at so-called permanent power sockets. For this purpose, a charging cable with an integrated control unit (ICCB: In-Cable Control Box) is required. The ICCB has the function of verifying the vehicle's readiness for charging via communication with the electric vehicle, switching on the power when required, and continuously monitoring the secure electrical connection to the electric vehicle. It can also disconnect it in the event of a fault.

[0004] Regardless of the charging method, electric vehicle drivers expect a fast, yet uncomplicated, simple charging process. The demand for the shortest possible charging times for electric vehicles inevitably leads to high charging currents. As charging currents increase, so does the temperature stress on charging cables and charging plugs, especially high-voltage (HV) charging plugs. Therefore, temperature monitoring is essential for safe operation.

[0005] Charging systems with temperature monitoring are already known from the prior art. For example, DE 10 2011 084 527 A1 describes a charging infrastructure or charging system in which a temperature sensor is provided on the electrical plugs or connectors. This sensor monitors the temperature of the plug and, if the temperature rises, initiates a reduction in the charging current via a control system.

[0006] Furthermore, DE 10 2021 203 362 A1 discloses a charging cable with a switching unit which is configured to de-energize the current flow through the charging cable depending on a fault current and temperature monitoring, thereby increasing the safety of the charging process.

[0007] DE 20 2015 009 850 U1 also discloses a connector for a charging cable of an electric or hybrid vehicle. The connector comprises a connector housing and live current contacts (pins / pins) for a charging current, in particular of a battery of the electric or hybrid vehicle. Furthermore, at least one temperature sensor for charging control and / or charging monitoring is arranged in the connector housing. The temperature sensor is embedded in a chamber in which at least one live area of ​​the current contacts is guided.

[0008] However, the current state of the art always has the disadvantage that the temperature sensors are located in close proximity to or in the pins / power contacts of the charging connectors. This means that temperature measurement in electric vehicle charging connectors is achieved by placing and physically touching insulated temperature sensors in or on the pin. The insulation required for this makes temperature measurement slow.

[0009] The object of the disclosure is therefore to avoid or at least mitigate the disadvantages of the prior art. In particular, a method for determining the temperature of a pin on a connector for power transmission, in particular a charging connector for an electric vehicle, with high accuracy and a fast response time is to be provided.

[0010] This task is solved in a generic method according to the disclosure by the following steps: - Detecting a measuring temperature by a temperature sensor spaced from the pin; - Determining a compensation temperature based on a predefined characteristic map; and - Calculate the temperature of the pin by adding the measured temperature and the compensation temperature.

[0011] This has the advantage that no insulation is required for the temperature sensor, so that it ensures a quick provision of the temperature of the pin and thus enables fast and reliable charging current control.

[0012] Advantageous embodiments are claimed in the subclaims and are explained in more detail below.

[0013] The disclosed method is preferably used for charging connectors for electric vehicles. However, it can also be used to determine the temperature of a pin on any other connector for power transmission.

[0014] In an advantageous embodiment, the characteristic map can represent a heat transfer function which depends on operating data (such as a structural design) and on environmental influences.

[0015] The operating data can preferably include at least one parameter from the thickness of an insulation layer, a heat transfer area, a distance between the pin and the temperature sensor, and a supply voltage. The thickness of an insulation layer corresponds to the spatial extent of a layer of thermally and / or electrically insulating material. The heat transfer area is defined as an area over which the pin and the temperature sensor exchange heat, in particular via radiation and convection, whereas the supply voltage is the voltage with which the charging process is carried out.

[0016] Furthermore, it may be expedient for the environmental influences to include at least one parameter from an initial temperature, an ambient temperature, and an air fraction. The initial temperature is the temperature of the plug or charging connector at the beginning of the charging process or at the beginning of the temperature determination according to the disclosure, while the ambient temperature is the temperature of the ambient air. The air fraction essentially determines the amount of heat transferred convectively.

[0017] According to a particularly preferred embodiment, the heat transfer function can also depend on aging variables, in particular a corrosion component. This means that the heat transfer function makes it possible to consider wear or aging processes and their influence on temperature development.

[0018] Furthermore, the present disclosure relates to a connector for power transmission, and in particular to a charging connector for an electric vehicle, comprising at least one pin, a temperature sensor spaced apart from the pin, and a preferably integrated control unit. According to the disclosure, the control unit is configured to carry out the method according to the disclosure.

[0019] In this case, it can be particularly advantageous if the temperature sensor is spaced from the pin by a spacer element. The spacer element can preferably have a receiving opening for receiving the pin and at least one locking means, preferably a snap hook, which engages with a corresponding counterstructure, in particular an undercut / recess, of the pin, thus securing the spacer element to the pin. According to a particularly preferred embodiment, the at least one locking means can be designed as at least one snap hook projecting radially inward from an inner circumferential surface of the receiving opening.

[0020] In other words, the disclosure relates to a method for determining a temperature in which an algorithm for a temperature measurement correction can be created by using various parameters, so that the temperature difference between the temperature of the real measurement object and the measured temperature at the measurement sensor can be compensated.

[0021] The disclosure is explained below with the help of a drawing. It shows: Fig. 1 a partial perspective view of a pin of a charging plug according to the disclosure in accordance with a preferred embodiment; Fig. 2 a plan view of a spacer element of the disclosed charging plug according to the preferred embodiment; Fig. 3 is a perspective view of the pin and the spacer element of the disclosed charging plug according to the preferred embodiment in an unassembled state; Fig. 4 a perspective view of the pin and the spacer element of the charging plug according to the disclosed preferred embodiment in an assembled state; and Fig. 5 a time-temperature diagram.

[0022] The figures are merely schematic in nature and serve solely to facilitate understanding of the disclosure. The same elements are provided with the same reference numerals. The features of the individual embodiments can be interchanged.

[0023] In Fig. 1 shows a pin 1 of a charging connector 2 for an electric vehicle. Pin 1 is, as known from DE 20 2015 009 850 U1, a live current contact in a Fig. 1 not shown. To charge the electric vehicle, the charging plug 2 is inserted into a charging socket of a charging station so that pin 1 can make contact with the charging socket and thus ensure a current flow. This increases the temperature of pin 1. If the temperature of pin 1 exceeds a threshold temperature, a control unit 3 housed in the plug housing regulates the current flow. The control unit 3 is in Fig. 1 is shown only schematically.

[0024] To determine the temperature of pin 1, a temperature sensor 4 is arranged on pin 1. The temperature sensor 4 is attached to pin 1 via a spacer element 5, so that a defined distance exists between pin 1 and the temperature sensor 4. This means that the temperature sensor 4 is spaced apart from pin 1.

[0025] As in Fig. 2, the spacer element 5 has a substantially circular shape, with a receiving portion 6 in the form of a radially outwardly projecting tongue being formed on a peripheral portion. The temperature sensor 4 is received in the receiving portion 6. A receiving opening 7 is formed in the center of the spacer element 5, so that the spacer element 5, as shown in Fig. 3 and Fig. 4, must be pushed over pin 1 for assembly so that pin 1 protrudes through the receiving opening 7.

[0026] In order to fasten the spacer element 5 and thus the temperature sensor 4 to the pin 1, a plurality of snap hooks / latching tabs 8 are formed on an inner circumferential surface of the receiving opening 7. These snap hooks 8 are evenly distributed over the circumference and, when the spacer element 5 is mounted on the pin 1, engage behind a corresponding counterstructure formed or arranged on the pin 1, preferably in the form of an undercut. In other words, the spacer element 5 has snap hooks 8 projecting radially into the receiving opening 7 in order to be able to fasten the spacer element 5 to the pin 1 in a form-fitting manner. The snap hooks 8 latch with the counterstructure of the pin 1.

[0027] As mentioned above, the temperature sensor 4 is provided to output the temperature at pin 1 so that the control unit 3 can regulate the current flow based on the temperature of pin 1. Furthermore, the temperature sensor 4 is spaced apart from pin 1. This spacing leads to a deviation or difference between a measured temperature determined by the temperature sensor 4 and the actual temperature present at pin 1. Such a temperature difference can have critical consequences for the safety of the charging system. If the actual temperature is higher than the measured temperature, the control unit 3 does not regulate the current flow or regulates it too late, which can lead to damage.

[0028] Therefore, the control unit 3 of the charging plug 2 according to the disclosure is configured to execute a compensation method according to the disclosure. For this purpose, the measurement temperature is first measured by the temperature sensor 4 located at a distance from pin 1. Subsequently, the control unit 3 determines a compensation temperature based on a predefined characteristic map stored in the control unit 3. This compensation temperature is then added to the measurement temperature to obtain a corrected temperature at pin 1. Using this corrected temperature, the control unit 3 then performs the temperature monitoring.

[0029] As mentioned above, the characteristic map is stored in the control unit 3. The characteristic map was defined in advance through measurements and / or computer-aided simulations. According to the disclosure, the characteristic map represents a heat transfer function between the temperature sensor 4 and pin 1. The influencing parameters for the heat transfer function in the characteristic map include an initial temperature, an ambient temperature, a thickness of an insulation layer, a heat transfer surface, a distance between the temperature sensor 4 and pin 1, a supply voltage, air fractions, and a corrosion parameter.

[0030] This means that the characteristic map reflects both design and operational parameters, as well as environmental influences and aging variables. Furthermore, material variables, such as a heating gradient, can also be taken into account.

[0031] In Fig. 5, the temperature T is plotted against time t. The actual temperature at pin 1 is shown as a solid line. The measured temperature at temperature sensor 4 is shown as a dashed line, whereas the temperature corrected using the compensation method is shown as a dash-dot line. Fig. Figure 5 shows the temperature difference between the actual temperature and the measured temperature. It also shows that the compensation method makes it possible to adjust the measured temperature to the actual temperature, making the temperature difference negligible.

[0032] The disclosure is explained above using a preferred embodiment. The disclosed method is used to determine the temperature of pin 1 of charging plug 2. However, the present disclosure is in no way limited to application to charging plugs. Of course, the disclosed method can also be used to determine the temperature of a pin or current contact of any power transmission plug. List of reference symbols 1 pin 2 charging plugs 3 Control unit 4 Temperature sensor 5 spacer element 6 Recording section 7 Receiving opening 8 snap hooks / locking tabs QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2011 084 527 A1

[0005] DE 10 2021 203 362 A1

[0006] DE 20 2015 009 850 U1 [0007, 0023]

Claims

[1] Method for determining a temperature of a pin (1) on a connector for power transmission, in particular a charging connector (2) for an electric vehicle, comprising the following steps: - detecting a measuring temperature by a temperature sensor (4) spaced from the pin (1); - Determining a compensation temperature based on a predefined characteristic map; and - Calculate the temperature of pin (1) by adding the measuring temperature and the compensation temperature. [2] Method according to claim 1, characterized by that the characteristic map represents a heat transfer function which depends on operating data (a structural design) and environmental influences. [3] Method according to claim 2, characterized bythat the operating data include at least one parameter from a thickness of an insulation layer, a heat transfer area, a distance between the pin (1) and the temperature sensor (4) and a supply voltage. [4] Method according to claim 2 or 3, characterized by that the environmental influences include at least one parameter from an initial temperature, an ambient temperature and an air content. [5] Method according to one of the preceding claims 2 to 4, characterized by that the heat transfer function also depends on aging parameters, in particular a corrosion component. [6] Plug for power transmission, in particular charging plug (2) for an electric vehicle, with at least one pin (1), a temperature sensor (4) spaced from the pin (1) and a control unit (3), preferably integrated in the plug, characterized bythat the control unit (3) is arranged to carry out the method according to one of the preceding claims 1 to 5. [7] Plug according to claim 6, characterized by that the temperature sensor (4) is spaced from the pin (1) via a spacer element (5). [8] Plug according to claim 7, characterized by that the spacer element (5) has a receiving opening (7) for receiving the pin (1) and at least one locking means (8) which locks with a corresponding counter-structure of the pin (1) in order to fasten the spacer element (5) to the pin (1). [9] Plug according to claim 8, characterized by that the at least one locking means is designed as at least one snap hook (8) projecting radially inwardly from an inner circumferential surface of the receiving opening (7).

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