DC charging cable and method for determining a temperature of the DC charging cable

Abstract

The application relates to direct current, DC, charging cable including two DC conductors configured for transmitting electrical energy between an electrical vehicle and a charging device, at least a signal line having a first signal line end and a second, opposite signal line end and a control device, the first signal line end is connected at a first connection point to one of the DC conductors, and the control device is configured for measuring a voltage difference between the second signal line end and a second connection point of the one of the DC conductors distant to the first connection point for determining a temperature of the DC charging cable.

Claims

1. A direct current (DC), charging cable, comprising: two DC conductors configured for transmitting electrical current from a charging device to an electrical vehicle, at least a signal line having a first signal line end and a second, opposite signal line end, and a control device, wherein: the first signal line end is connected at a first connection point to one of the DC conductors, and the control device connects the second signal line end to the one of the DC conductors and is configured for measuring a voltage difference between the second signal line end and a second connection point of the one of the DC conductors distant to the first connection point due to an internal resistance of the one of the DC conductors for determining a temperature of the DC charging cable.

2. The DC charging cable according to claim 1, further comprising a voltage measurement device arranged between the second signal line end and the second connection point, and/or wherein the signal line runs between the first connection point and the second connection point parallel to the one of the DC conductors.

3. The DC charging cable according to claim 1, further comprising a second signal line having a respective first signal line end and a respective second, opposite signal line end, wherein the respective first signal line end is connected to the other one of the DC conductors at a respective first connection point, and the control device is configured for measuring a second voltage difference between the respective second signal line end and a respective second connection point of the other one of the DC conductors distant to the respective first connection point for determining a second temperature of the DC charging cable.

4. The DC charging cable according to claim 3, wherein the control device is configured for combining the measured voltage difference and the measured second voltage difference and/or the determined temperature and the determined second temperature.

5. The DC charging cable according to claim 1, wherein the DC charging cable comprises a first end and a second, opposite end, the first connection point is at the first end and the second connection point is at the second end.

6. The DC charging cable according to claim 1, comprising a charging connector to which a first end or a second, opposite end of the DC charging cable is connected, wherein the first connection point is arranged within the charging connector.

7. The DC charging cable according to claim 1, further comprising a charging device to which a first end or a second, opposite end of the DC charging cable is connected, whereby wherein the second connection point is arranged within the charging device.

8. The DC charging cable according to claim 1, wherein the control device is configured for calibrating the measured voltage difference in regard to the temperature and/or the control device is configured for measuring a current of at least one of the DC conductors.

9. The DC charging cable according to claim 1, wherein the control device is configured for determining the temperature based on a predetermined calibrated resistance at a known temperature of the DC conductors and/or the control device is configured for controlling a charging current of the DC conductors in response to the measured temperature.

10. A method for determining a temperature of a DC charging cable, comprising two DC conductors configured for transmitting electrical current from a charging device and an electrical vehicle, at least a signal line having a first signal line end and a second, opposite signal line end, wherein the first signal line end is connected at a first connection point to one of the DC conductors, and comprising: measuring, by a control device, a voltage difference between the second signal line end and the one of the DC conductors at a second connection point distant to the first connection point due to an internal resistance of the one of the DC conductors for determining the temperature of the DC charging cable.

11. The method according to claim 10, wherein the signal line runs between the first connection point and the second connection point parallel to the one of the DC conductors.

12. The method according to claim 11, further comprising a second signal line having a respective first signal line end and a respective second, opposite signal line end, wherein the respective first signal line end is connected to the other one of the DC conductors at a respective first connection point, and which further comprises measuring a second voltage difference between the respective second signal line end and a respective second connection point of the other one of the DC conductors distant to the respective first connection point for determining a second temperature of the DC charging cable.

13. The method according to claim 12, which further comprises combining the measured voltage difference and the measured second voltage difference and/or the determined temperature and the determined second temperature.

14. The method according to claim 12, wherein the DC charging cable comprises a first end and a second, opposite end, the first connection point is at the first end and the second connection point is at the second end.

15. The method according to claim 12, further comprising a charging connector to which a first end or a second, opposite end of the DC charging cable is connected, wherein the first connection point is arranged within the charging connector.

16. The method according to claim 12, further comprising a charging device to which a first end or a second, opposite end of the DC charging cable is connected, wherein the second connection point is arranged within the charging device.

17. The method according to claim 12, further comprising calibrating the measured voltage difference in regard to the temperature.

18. The method according to claim 10, further comprising measuring a current of at least one of the DC conductors.

19. The method according to claim 10, further comprising determining the temperature based on a predetermined resistance at a known temperature of the DC conductors.

20. The method according to claim 12, further comprising controlling a charging current of the DC conductors in response to the measured temperature.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

(2) In the drawings:

(3) FIG. 1 shows a direct current, DC, charging cable according to an exemplary implementation in a schematic view.

DESCRIPTION OF EMBODIMENTS

(4) FIG. 1 shows a direct current, DC, charging cable according to an exemplary implementation in a schematic view. The DC charging cable comprises two DC conductors 1, 2 for transmitting electrical energy between an electrical vehicle 3 and a charging device 4, with one DC conductor 1 having a positive potential and the other DC conductor 2 having a negative potential. The DC charging cable may comprise further conductors, such as a Proximity Pilot, PP, line for transmitting a PP signal, a Control Pilot, CP, line for transmitting a CP signal and/or a PE line for transmitting a PE signal, which are not depicted in FIG. 1. The DC conductors 1, 2 comprise a diameter of, typically, between 25 to 50 mm.sup.2 for transmitting typical charging currents of typically 500 A.

(5) A charging connector 5 is connected to a first end 6 of the DC charging cable, whereas a second, opposite end 7 of the DC charging cable is connected to the charging device 4. Such way the DC charging cable extends between its first end 6 and its second end 7 along a distance of 5 m. The charging connector 5 comprises contact pins 8, which are connected to the first ends 6 of the DC conductors 1, 2 for electrically connecting the electrical vehicle 3.

(6) In addition to the two DC conductors 1, 2, the DC charging cable comprises two signal lines 9, 10, depicted as dotted lines, which run in parallel in an insulated manner to the DC conductors 1, 2 along the distance of 5 m. Specifically, referring to FIG. 1, the upper signal line 9 runs parallel to the upper DC conductor 1 and is connected at its first signal line end 11 at a first connection point 12 to the upper DC conductor 1 at the upper contact pin 8. In an analogous manner, the lower signal line 10 runs parallel to the lower DC conductor 2 and is connected at its respective first signal line end 11 at a respective first connection point 12 to the lower DC conductor 2 at the respective lower contact pin 8.

(7) A second, opposite signal line end 13 of the upper signal line 9 is connected via a voltage measurement device 15 at a second connection point 14 arranged within the charging device 4 to the upper DC conductor 1. In an analogous manner, a respective second, opposite signal line end 13 of the lower signal line 9 is connected via a respective voltage measurement device 15 at a respective second connection point 14 arranged within the charging device 4 to the lower DC conductor 2. Such way the second connection point 14 is arranged distant to the first connection point 12.

(8) A computerized control device 16 is arranged within the charging device 4 and is configured for measuring a respective voltage difference between both second signal line ends 13 and both the second connection points 14. The control device 16 further measures a charging current of the DC conductors 1, 2. Based on a calibrated resistance of the DC conductors 1, 2 at a known temperature, the control device 16 determines from the measured voltage difference and the measure charging current an actual temperature of the DC conductors 1, 2 respectively of copper of the conductors 1, 2. Thereby, the control device 16 may combine or calculate an average of the measured voltage differences, charging currents and/or temperatures measured at respectively calculated for the upper DC conductor 9 and the lower conductor 10. It could be further required that the control device calibrates the measure voltage difference in regard to the temperature, for example by comparing with reference data for the voltage difference and temperature.

(9) In response to the determined temperature, the control device 16 may control the charging current of the DC conductors 1, 2. If the temperature of the DC conductors 1, 2 exceed a predefined threshold, the charging current can be reduced by a certain degree or even turned off. For example, charging may be stopped if the temperature exceeds 70° Celsius and can be resumed if the temperature has fallen to 50° Celsius. Alternatively, the control device 16 may control the charging current of the DC conductors 1, 2 such that the temperature of the DC conductors 1, 2 does not exceed a predefined threshold.

(10) While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to be disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting scope.

REFERENCE SIGNS LIST

(11) 1 (Upper) DC conductor 2 (Lower) DC conductor 3 Electrical vehicle 4 Charging device 5 Charging connector 6 First end 7 Second, opposite end 8 Contact pin 9 (Upper) Signal line 10 (Lower) Signal line 11 First signal line end 12 First connection point 13 Second, opposite signal line end 14 Second connection point 15 Measurement device 16 Control device