The invention relates to a structure comprising at least one thermal management element comprising: a composite body (3) containing at least one phase change material (PCM) in a structuring rigid matrix, such that the composite body is self-supporting regardless of the phase of the phase change material contained, the composite body (3) being shaped to locally externally present at least one elongated depression (11) which by itself defines a channel wall (13) suitable for the circulation of a fluid.