Electrolysis or co-electrolysis reactor (SOEC) or fuel cell (SOFC) with electrochemical cell stacking by preassembled modules, and associated production process

An electrochemical device configured to function at high temperature, the device comprising:

• a stack comprising a first and a second preassembled module, in which each preassembled module is obtained by tightening applied by a bolt system and comprises:
• a stack of electrochemical cells comprising SOEC/SOFC solid oxides;
• a plurality of electrical and fluidic interconnectors, each interconnector comprising a component comprising gastight electrically conductive material to convey or collect the electrical current to the stack of electrochemical cells and to convey, collect, and circulate gases on each electrode of each electrochemical cell, the interconnectors being individually arranged on either side of each of the electrochemical cells;
• a first and a second stiffening plate between which the stack is arranged,
• wherein the first and second stiffening plates, arranged in the stack of modules, form electrical and fluidic interconnectors between modules, the first and second stiffening plate, arranged at the ends of the stack of modules, forming electrical and fluidic connectors to convey or collect the electrical current between the electrochemical device and the exterior and to convey, collect, and circulate the gases between the electrochemical device and the exterior, wherein at least one electrical contact member is arranged between two adjacent modules with contact between their stiffening plates, and
• wherein at least one seal is arranged between two adjacent modules to ensure the leaktightness around each gas inlet/outlet from one module to another.