In a coil unit of a device for inductive transmission of electrical power with a cover, a base and a coil arranged between the cover and base. During operation of the device, the cover faces another coil unit and the base faces away from it. At least one support element, which mechanically supports the cover on the base, is arranged between the cover and the base. At least one cavity is formed between the cover and the support element by protrusions on the cover and/or on the support element, whereby the cover lies on the support element, and/or at least one cavity is formed between the base and the support element by protrusions on the support element and/or on the base, whereby the support element lies on the base. Sensors or elements for magnetic flux guidance can be arranged protected from mechanical load in such a cavity.