Apparatus (100) and method for testing cell contact of battery cells (102) of a battery module (104), which battery cells are electrically connected in parallel via a contacting system (106, 107). The apparatus includes a sensor positioning system (108) for positioning a sensor device (110) at a plurality of test points (112) of the battery module, which is movable along a longitudinal axis (X), a transverse axis (Y), and a vertical axis (Z), and a current generation circuit (114) for generating a battery cell current (I), which is a discharging current from the battery cell or a charging current into the battery cell. The sensor device includes at least one field sensor (118), which, after the sensor device is positioned at one of the test points, detects a field in the region of the test point, which is generated by the battery cell current generated with the current generation circuit.

Presented herein are a flux detection circuit for sensing magnetic flux via a magnetic flux probe and method therein. A magnetic flux probe comprising circuit elements and forming a loop around a magnetic core avails interconnection of a flux-sensitive trace across a winding window. The flux detection circuit is configured to measure an electromotive force (emf) of one or more elements of the loop; and at least one of the circuit elements may be adjustable (e.g., may comprise a variable resistance). In this manner the magnetic flux probe and flux detection circuit may be calibrated to accurately detect a signal proportional to the time-varying magnetic flux and to provide the signal across a winding window.

Magnetic sensing device integrated in a magnetic switch device that makes or breaks contact in the presence of an external magnetic field, comprising: a first transistor biased at a first terminal by a first bias voltage and a first magnetoresistive element having a first resistance variable with the external magnetic field. At a reference field strength, the first resistance has a first reference resistance value, and the first bias voltage is adjustable to control a first current at the second terminal of the first transistor at a first reference current value. When the external magnetic field is varied around the reference field strength, the first variable resistance varies around the first reference resistance value by a resistance delta, such that the first current modulates around the first reference current value by a current delta. A magnetic switch device comprising the magnetic sensing device is also disclosed.