NOVELTY - The device (1) has a half-case (16) resting on a head (11) of a screw (23), and another half-case (17) resting on a heat sink (4) of a Peltier assembly directly above a thread (12) of the screw, where the half-cases are connected to each other by a connector (20). The head of the screw rests on another heat sink (3) of the Peltier assembly, and the thread is engaged on the former heat sink. The heat sinks respectively include heat exchange fins (8, 10) and bases (7, 9) that are in contact with a thermoelectric cell (2) of the Peltier assembly.    USE - Device for fixing a Peltier assembly that is utilized in a ventilation system of an air conditioning system for cooling or heating a battery (all claimed) of a motor vehicle i.e. electric vehicle.    ADVANTAGE - The half-cases are connected to each other by the connector, thus ensuring the mechanical connection between the half-cases to retain them one against the other and to maintain the Peltier assembly in place, and hence allowing the Peltier assembly to be installed in the ventilation system in a compact and easy manner. The screw head receives one of the half-cases and rests on one of the heat sinks, and the thread is engaged on the other heat sink, thus avoiding the transmission of mechanical force from the fixing device toward the thermoelectric cell, and hence ensuring the integrity of the cell so as to improve the reliability of the Peltier assembly.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) a ventilation system comprising a fixing device    (2) an air conditioning system of a battery, comprising a ventilation system.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic sectional view of a Peltier assembly fixing device.    Fixing device (1)    Thermoelectric cell (2)    Heat sinks (3, 4)    Bases of heat sinks (7, 9)    Heat exchange fins (8, 10)    Head of screw (11)    Thread of screw (12)    Half-cases (16, 17)    Connector (20)    Screw (23)