In a connector system for a battery system, the connector system includes: a connector configured to electrically connect to a counterpart of the connector, wherein the connector comprises a negative connection element and a positive connection element; a first temperature sensor thermally connected to the negative connection element; a second temperature sensor thermally connected to the positive connection element; and a control unit configured to receive a first temperature signal from the first temperature sensor and to receive a second temperature signal from the second temperature sensor; wherein the control unit configured to generate a first value based on the first temperature signal and a second value based on the second temperature signal; and wherein the control unit is further configured to generate an alert signal in response to an absolute value of a difference between the first value and the second value exceeding a predefined threshold.