Standard Equivalent Air Leak Rate Conversions for Sealed Commercial Pouch Cells
Standard air equivalent leak conversions transform empirical helium mass spectrometer readings into precise air ingress and solvent loss metrics for pouch cells.
Tab Sealant Delamination
Meaning
Loss of adhesion between the polymer sealant and the metallic terminal lead of a pouch cell creates an open leakage path. This separation process is called tab sealant delamination, and it impairs the hermetic seal of the cell. The failure allows moisture to penetrate the casing and dry the electrolyte.
This separation is a critical defect that can lead to rapid cell failure.
Mechanical Strain
External forces and thermal cycling accelerate the separation of the sealant from the metal surface. During normal operation, the expansion and contraction of the electrode stack apply stress to the terminal region, triggering tab sealant delamination in weak bonds. Continuous vibrations in vehicle applications further weaken the adhesive interface.
This mechanical wear is common when the sealant material lacks elasticity.
Failure Pathway
Capillary pathways form as the adhesive layer separates from the copper or aluminum lead. When tab sealant delamination occurs, moisture from the ambient air enters the cell along the metal-polymer boundary. This ingress reacts with the internal chemistry, causing gas generation and swelling of the pouch cell.
The resulting internal pressure can force the pouch open, leading to a complete loss of function. If the cell swell is severe, it can damage surrounding cells in a packed module, making tab sealant delamination a danger to the entire system.
Purchasing Risk
Procurement specifications require strict peel-strength testing of the terminal seals to verify adhesive quality. Sourcing teams analyze tab sealant delamination rates to compare the reliability of pouch cell suppliers. Purchasing decisions depend on the cells passing long-term thermal humidity chamber tests without seal failures.
This step avoids the high cost of field campaigns to replace leaking battery packs.