Meaning
Spatial profile of electrical current flow across the surface of an electrode during battery operation. Variations in the current density distribution lead to localized heating and uneven lithium depletion. If left unmanaged, these variations accelerate local aging and can cause safety hazards in high-energy cells.
Spatial Gradient
Electrodynamic variations emerge due to differences in path length, local temperature, and electrode thickness. Localized hotspots are formed where the current density distribution concentrates into narrow regions of the electrode surface. This non-uniformity shortens the lifetime of the cell by creating localized overpotentials.
In thick electrodes, the liquid phase resistance further concentrates the current near the separator, which leaves the deeper regions of the electrode underutilized and creates steep concentration gradients during rapid discharge events.
Degradation Vector
Fast-charging protocols can trigger localized lithium plating in areas where the flow is highly concentrated. If the current density distribution exceeds a threshold, the local potential falls below the deposition limit. This initiates dendritic growth that eventually penetrates the separator.
Optimization Pathway
Advanced tab placement and electrode thickness grading can minimize these lateral gradients. Modern manufacturing techniques adjust the current density distribution to be as uniform as possible. Uniform flow ensures that the active material is used efficiently across the entire surface.
