NOVELTY - A battery module comprises: a set of battery cells; a connecting member arranged to connect at least two electrodes of the set of battery cells to each other; and a voltage detector arranged to detect a voltage between a first region and a second region of the connecting member that are spaced apart from each other.    USE - The battery module and battery system are useful for an electric vehicle (claimed).    ADVANTAGE - The battery module is highly efficient and capable of detecting a current flowing through a set of battery cells with a simple configuration.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are:    (1) a battery system comprising: a battery module; and a current calculator, where the battery module includes: a set of battery cells; a connecting member arranged to connect at least two electrodes of the set of battery cells to each other; and a voltage detector arranged to detect a voltage between a first region and a second region of the connecting member that are spaced apart from each other, and the current calculator calculates a current flowing through the connecting member based on the voltage between the first and second regions detected by the voltage detector of the battery module; and    (2) an electric vehicle comprising: a battery module; a motor arranged to be driven by power supplied from the battery module; and a drive wheel rotated by a torque of the motor, where the battery module includes: a set of battery cells; a connecting member arranged to connect at least two electrodes of the set of battery cells to each other; and a voltage detector arranged to detect a voltage between a first region and a second region of the connecting member that are spaced apart from each other.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view plan for explaining connection between the set of bus bars and a detecting circuit.    First battery cell (10)    Detecting circuit (20)    Attachment portion (42)    Flexible printed circuit board (50)    Conductor lines (51, 52, 53)    Conductive plate (59)    Amplifying circuit (410)