Method for fabricating at least first and second electrochemical devices, such as electrochromic systems or energy storage systems, for example microbatteries, batteries or supercapacitors, comprising the following successive steps: a) providing a substrate comprising a first group of complete individual entities, each complete individual entity comprising: - a first current collector, of a first polarity, - a first electrode, - an ionically conductive and electrically insulating thin layer, - a second electrode, - a second current collector, of a second polarity, b) cutting the substrate so as to form at least second and third groups of individual entities (8, 9) each comprising a plurality of complete individual entities from the first group of complete individual entities, cutting being performed so as to form a plurality of non-complete individual entities in each of the second and third groups of individual entities (8, 9), all or part of the individual entities (8, 9) located at the periphery of the second group of individual entities (8, 9) and/or of the third group of individual entities (8, 9) being non-complete individual entities, c) electrically connecting the current collectors (4, 6) of the same polarity of the complete individual entities of the second group of individual entities in parallel without electrically connecting the non-complete individual entities to form the first electrochemical device, d) electrically connecting the current collectors (4, 6) of the same polarity of the complete individual entities of the third group of individual entities in parallel without electrically connecting the non-complete individual entities to form the second electrochemical device. a) providing a substrate comprising a first group of complete individual entities, each complete individual entity comprising: - a first current collector, of a first polarity, - a first electrode, - an ionically conductive and electrically insulating thin layer, - a second electrode, - a second current collector, of a second polarity, - a first current collector, of a first polarity, - a first electrode, - an ionically conductive and electrically insulating thin layer, - a second electrode, - a second current collector, of a second polarity, b) cutting the substrate so as to form at least second and third groups of individual entities (8, 9) each comprising a plurality of complete individual entities from the first group of complete individual entities, cutting being performed so as to form a plurality of non-complete individual entities in each of the second and third groups of individual entities (8, 9), all or part of the individual entities (8, 9) located at the periphery of the second group of individual entities (8, 9) and/or of the third group of individual entities (8, 9) being non-complete individual entities, c) electrically connecting the current collectors (4, 6) of the same polarity of the complete individual entities of the second group of individual entities in parallel without electrically connecting the non-complete individual entities to form the first electrochemical device, d) electrically connecting the current collectors (4, 6) of the same polarity of the complete individual entities of the third group of individual entities in parallel without electrically connecting the non-complete individual entities to form the second electrochemical device.