Isothermal Terminal Calibration for High-Current Cell Testing
Active isothermal terminal calibration eliminates contact heat injection during high-current cell testing, preventing false capacity and cycle life data.
Cell Temperature Gradient
Meaning
Spatial variation in thermal energy measured between different points of an electrochemical unit during operation or rest. A cell temperature gradient develops when heat generation at the core exceeds the rate of dissipation at the surface. Persistent imbalances lead to non-uniform aging across the electrode surface.
Heat Distribution
Internal resistance generates thermal energy which must travel through layers of active material and current collectors. Poor conductivity in the thickness direction causes the center to stay hotter than the casing. This difference limits the maximum safe charging speed for the unit.
Thermal Management
Active cooling systems attempt to minimize the cell temperature gradient by extracting heat from the most accessible surfaces. Cold plates or liquid jackets are positioned to maximize the contact area. If the gradient becomes too steep, the internal chemical reactions occur at different rates in different layers.
Degradation Influence
Localized hot spots accelerate the growth of the solid electrolyte interphase layer in specific regions. This uneven wear reduces the total life of the pack even if the average temperature remains within limits. Operators monitor the cell temperature gradient to ensure that no single point reaches the threshold for separator damage.
Maintaining a uniform profile preserves the structural integrity of the lithium ion layers.