Lightweight All‐Solid‐State Pouch Cells Freed from High Stack Pressure

ABSTRACT

Since 2011, ionic conductivity of some sulfide‐ and halide‐based solid‐state electrolytes (SSEs) have already reached a level comparable to that of liquid electrolytes. Numerous companies worldwide have proposed diverse technical pathways for commercializing electric vehicles with ultra‐long driving ranges. However, the practical vehicular application of all‐solid‐state batteries (ASSBs) remains highly challenging and uncertain. One of the major obstacles is the requirement for high stack pressure, which typically relies on heavy metallic plates and thereby reduces the overall energy density of the module battery. This perspective compares practical all‐solid‐state pouch cells (ASSPCs) with conventional liquid batteries to analyze the origins of stack pressure requirements. The analysis is conducted from material, interfacial, and structural viewpoints, revealing the critical factors underlying this limitation. Subsequently, strategies are proposed to mitigate stack pressure from the current 20 MPa to 5 MPa for the first stage and to 2 MPa as the final target. The effect of stack pressure on cell‐to‐module energy density efficiency is also calculated to quantitative analysis. These insights provide practical suggestion from ASSPCs design to module‐level pressure management.