Modular vehicle system, with - an electric vehicle (2, 2'), particularly a light electric vehicle, with at least - an on-board power supply system (13, 101) for energy supply of an electric drive unit, - a control device, - an interface (4, 4', 114), connected to the on-board power supply system (13, 101) for connection of at least one module (3, 17, 120), and - a first locking means (9, 19) arranged at the interface (4, 4', 114); and - a module (3, 17, 120), with - an electric arrangement, - a module control (14, 125), which is configured to communicate with the control device and which is connected to an electrically operable locking drive (30, 121a), - a connecting element (6, 6', 121), separably connectable to the interface (4, 4', 114), for connection of the electric arrangement with the on-board power supply system (13, 101), and - a second locking means (11, 22) arranged at the connecting element (6, 6', 121), formed for engagement with the first locking means (9, 19), wherein - the locking drive (30, 121a) is arranged at least at one of the locking means (9, 11, 19, 22) to move at least one of the locking means (9, 11, 19, 22) between a free position and a locking position, - in the free position, the connecting element (6, 6', 121) is separable from the interface (4, 4', 114), and in the locking position, the connecting element (6, 6', 121) is mechanically locked with the interface (4, 4', 114), - the module control (14, 125) is further configured to send an identification signal to the control device upon connection of the connecting element (6, 6', 121) to the interface (4, 4', 114), and - the control device is configured to receive the identification signal, to compare the identification signal with at least one compatibility parameter, and in case that the identification signal corresponds to the compatibility parameter, to send an activation signal to the at least one locking drive (30, 121a) to lock the connecting element (6, 6', 121) to the interface (4, 4', 114). - an electric vehicle (2, 2'), particularly a light electric vehicle, with at least - an on-board power supply system (13, 101) for energy supply of an electric drive unit, - a control device, - an interface (4, 4', 114), connected to the on-board power supply system (13, 101) for connection of at least one module (3, 17, 120), and - a first locking means (9, 19) arranged at the interface (4, 4', 114); and - an on-board power supply system (13, 101) for energy supply of an electric drive unit, - a control device, - an interface (4, 4', 114), connected to the on-board power supply system (13, 101) for connection of at least one module (3, 17, 120), and - a first locking means (9, 19) arranged at the interface (4, 4', 114); and - a module (3, 17, 120), with - an electric arrangement, - a module control (14, 125), which is configured to communicate with the control device and which is connected to an electrically operable locking drive (30, 121a), - a connecting element (6, 6', 121), separably connectable to the interface (4, 4', 114), for connection of the electric arrangement with the on-board power supply system (13, 101), and - a second locking means (11, 22) arranged at the connecting element (6, 6', 121), formed for engagement with the first locking means (9, 19), wherein - an electric arrangement, - a module control (14, 125), which is configured to communicate with the control device and which is connected to an electrically operable locking drive (30, 121a), - a connecting element (6, 6', 121), separably connectable to the interface (4, 4', 114), for connection of the electric arrangement with the on-board power supply system (13, 101), and - a second locking means (11, 22) arranged at the connecting element (6, 6', 121), formed for engagement with the first locking means (9, 19), wherein - the locking drive (30, 121a) is arranged at least at one of the locking means (9, 11, 19, 22) to move at least one of the locking means (9, 11, 19, 22) between a free position and a locking position, - in the free position, the connecting element (6, 6', 121) is separable from the interface (4, 4', 114), and in the locking position, the connecting element (6, 6', 121) is mechanically locked with the interface (4, 4', 114), - the module control (14, 125) is further configured to send an identification signal to the control device upon connection of the connecting element (6, 6', 121) to the interface (4, 4', 114), and - the control device is configured to receive the identification signal, to compare the identification signal with at least one compatibility parameter, and in case that the identification signal corresponds to the compatibility parameter, to send an activation signal to the at least one locking drive (30, 121a) to lock the connecting element (6, 6', 121) to the interface (4, 4', 114).