Lithium-ion Battery Electrode Density Gradient Design

The invention applies local quality by creating distinct high-density portions and low-density portions with different mixture densities within the same electrode plate. The high-density portions have higher active material concentration for capacity, while low-density portions have lower concentration for better electrolyte penetration. This local differentiation resolves the contradiction by allowing each region to optimize for its specific function rather than using a uniform structure throughout.

The invention employs asymmetry by making the high-density portions larger in area than the low-density portions, breaking the symmetric alternating pattern of equal-sized regions. This asymmetric design ensures that the total capacity-contributing high-density regions dominate the electrode plate area, while the smaller low-density regions provide sufficient electrolyte pathways without compromising overall capacity.

The invention applies preliminary action by incorporating the density differentiation directly into the initial electrode coating application process. Instead of applying a uniform coating and then adding a second layer to create high-density portions, the method initially applies the electrode coating material with spatially varying thickness or composition to directly form both high-density and low-density portions in a single step, eliminating subsequent re-application operations.

The invention merges the functions of creating density variations and forming the electrode structure into a single coating and drying process. By combining what would otherwise be separate operations (applying coating material, creating density variations, drying, rolling) into an integrated process where the coating application itself establishes the density pattern, the manufacturing complexity and cost are reduced while maintaining the conduction rate balance.