Traction battery charging station

A traction battery charging station for charging a traction battery of a motor vehicle having an electric traction motor, said traction battery charging station comprising:

• a power/voltage converter that is configured to feed an electrical DC voltage charging power into a pair of two charging lines during a charging operation;
• a charging controller;
• and
• an insulation monitor having two electrical measuring resistors that are each connected to a charging line and are configured to be connected to protective earth via a respective resistor switch, wherein the insulation monitor is configured to monitor the electrical insulation of the pair of charging lines with respect to the protective earth during non-charging and during charging of the traction battery,
• wherein the insulation monitor has a test mode controller that has stored and is configured to control a non-restricted non-charging test mode in which one of the resistor switches is closed and the other resistor switch is open at the same time, and a symmetric charging test mode in which both of the resistor switches are either closed at the same time or open at the same time, and
• wherein the pair of charging lines opens into a charging station-side charging plug that has a connection sensor that is configured to detect connection of the charging station-side charging plug to a vehicle-side charging socket, wherein the test mode controller activates only the charging test mode when connection is reported by the connection sensor.

A method for operating a traction battery charging station for charging a traction battery of a motor vehicle having an electric traction motor, said traction battery charging station including (a) a power/voltage converter that is configured to feed an electrical DC voltage charging power into a pair of two charging lines during a charging operation, (b) a charging controller, and (c) an insulation monitor having a test mode controller and two electrical measuring resistors that are each connected to a respective one of the two charging lines and are configured to be connected to protective earth via a respective resistor switch, wherein the insulation monitor is configured to monitor the electrical insulation of the pair of charging lines with respect to the protective earth during non-charging and during charging of the traction battery, said method comprising:

• wherein, when the vehicle is electrically connected to the charging station via the two charging lines and the charging station is not charging the vehicle, the test mode controller performs:
• (i) a non-symmetric non-restricted non-charging test mode in which one of the resistor switches is closed and the other resistor switch is open at the same time, and
• (ii) a symmetric charging test mode in which both of the resistor switches are either closed at the same time or open at the same time,
• wherein, when the vehicle is electrically connected to the charging station via the two charging lines and the charging station is charging the vehicle, the test mode controller performs the symmetric charging test mode without performing the non-symmetric non-restricted non-charging test mode.