The disclosure relates to an application device for applying an application agent (e.g. heat-conducting paste) into a cavity, in particular in a battery module of an electric battery. The application device according to the disclosure comprises a nozzle for dispensing the application agent through the nozzle and a first pressure sensor for measuring a first pressure reading (pA, pB) of the application agent upstream of the nozzle. The disclosure additionally provides a second pressure sensor for measuring a second pressure reading (pD) of the coating agent downstream of the first pressure sensor, in particular in the nozzle. Furthermore, the disclosure comprises a corresponding application method.