NOVELTY - The device (1) has a sensor (14) determining of a fluid level and a cell condition and provided in a lower area (13) and an electromagnetically operated valve (5) with magnets (10, 11). An adapter (8) for automatically filling an individual galvanic cell with fluid is provided in an upper area (6). The sensor detects temperature of the individual galvanic cell, and a data interface is provided for transferring data of the individual galvanic cell. A base body (2) is made of electrically insulating plastic and/or electrically conducting plastic.    USE - Used for closing and/or filling an access opening e.g. filling opening, of an individual galvanic cell of a rechargeable battery and/or battery, which is utilized for supplying power (claimed).    ADVANTAGE - The sensor determines the fluid level and the cell condition and is provided in the lower area, thus ensuring the operational reliability of the device in an improved and durable manner. The utilization of the electromagnetically operated valve enables accurate charging of the cell and avoiding the danger due to floating defects of refilling process of the galvanic cell. The device enables closing of the cell access opening and receiving desired information about the physical conditions of the galvanic cells of the battery or rechargeable battery, without utilizing a special testing device.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) an arrangement having a number of closing devices for closing access openings e.g. filler openings, of galvanic cells    (2) a method of determining a condition of cells    (3) a method of manufacturing a device for closing and/or filling an individual galvanic cell.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic perspective view of a device for closing and filling an access opening of an individual galvanic cell with an electromagnetically operated valve.    Individual galvanic cell`s access opening closing and/or filling device (1)    Base body (2)    Electromagnetically operated valve (5)    Upper area (6)    Adapter (8)    Magnets (10, 11)    Lower area (13)    Sensor (14)