Abstract: A fixing device for releasable fixing an electrical energy accumulator to a carrying structure of a motor vehicle includes at least one insertion bolt and a receiver unit for the insertion bolt which are provided on the carrying structure and on the energy accumulator (or vice versa). The insertion bolt includes a retaining protrusion and the receiver unit includes a cage and a locking element mounted in the cage. The cage includes an insertion opening into which the insertion bolt can be introduced along an insertion direction, and the locking element can be moved between a release position and a locked position. In the release position, the locking element opens the insertion opening for introduction of the insertion bolt and in the locked position engages behind the retaining protrusion of the insertion bolt when the insertion bolt is introduced in the insertion opening of the cage.