Battery Tab Recess Design for Energy Density

The patent applies local quality by creating a recess in the active material layer specifically at the tab location. This recess provides localized mechanical support and stability for the tab element without requiring the entire current collector layer to be thicker. The solution addresses the mechanical stability issue only where needed (at the tab connection point) rather than uniformly across the entire battery structure, thereby maintaining high energy density while ensuring adequate mechanical strength for solderability and tab support.

The recess structure concentrates the current collection function at the tab location where it is most needed. By providing a localized recess that accommodates the tab element, the patent ensures adequate electrical contact and current collection efficiency at the critical connection point without requiring a uniformly thick current collector layer across the entire battery. This localized approach maintains low ESR at the connection interface while maximizing active material content in the remaining volume.

The patent resolves this contradiction by applying the local quality principle - creating a recess in the active material layer only at the specific location where the tab element connects. This localized structural modification provides the necessary mechanical stability and support for the tab connection without requiring the entire current collector layer to be of minimum thickness. The result is that the majority of the battery volume can be optimized with thinner current collector layers, thereby increasing energy density while maintaining adequate mechanical stability at the critical tab connection points.