Electrically controllable device having variable optical/energy properties in transmission or in reflection, comprising at least one carrier substrate provided with a stack of electrochromically functional layers, including at least two electrochromic active layers, separated by an electrolyte, the said stack being placed between two current leads, namely the lower current lead and the upper current lead respectively (“lower” corresponding to the current lead closest to the carrier substrate, as opposed to the “upper” current lead that is furthest from the said substrate), characterized in that the stack of functional layers is joined to at least one polymer film, the percentage shrinkage of which is between 0.6 and 2.0% and preferably between 0.8 and 1.5%.