Meaning
Spatial temperature differences occur at the junction between the electrode current collectors and the external terminals during operation. These tab boundary thermal gradients are caused by the high current density and localized resistance at the terminal connections. The gradient’s impact is most severe during high-power discharge and fast charging cycles.
Managing these localized temperature differences is critical for cell safety.
Gradient Genesis
The physical transition from the thin current collector foil to the thicker tab creates a bottleneck for current flow. This constriction generates significant joule heat in a very small volume. If the heat is not removed quickly, the local temperature rises rapidly.
This rapid rise creates a sharp thermal gradient across the boundary.
Degradation Path
Sharp temperature differences across the tab boundary lead to non-uniform current distribution and localized chemical stress. The hotter regions experience faster solid electrolyte interphase growth and active material loss. This uneven aging can cause premature cell failure and reduce overall pack capacity.
It is a major focus of thermal management engineering.
Sourcing Strategy
Procurement teams analyze these localized thermal profiles to select cells with optimized tab designs. Cells that feature wider tabs or multiple tab connections exhibit much lower thermal gradients. This selection leads to safer battery packs and reduces the need for aggressive cooling.
It ensures higher reliability in demanding applications.
