Pouch Cell Heat Seal Micro-Void Detection and Transport Leak Resistance
Pouch cell heat seals require precise thermal pressing and non-destructive inline acoustic or helium screening to prevent micro-void leaks during transit.
ASTM D3078
Meaning
Standardized test protocol establishes a method for determining leaks in flexible packaging by bubble emission. In battery manufacturing, astm d3078 is applied to verify the hermeticity of pouch cells under a vacuum. This test exposes the sealed cell to differential pressure while submerged in a fluid to locate physical breaches.
Vacuum Application
Submerging the pouch cell in a heavy liquid like silicone oil begins the evaluation. The chamber is sealed and a vacuum is drawn to create a pressure differential. This difference causes the flexible pouch to expand, forcing gas or solvent out through any imperfect seals.
Leakage Detection
Rising bubbles in the liquid reveal the exact location of any seal failure. Technicians observe the cell for a specified period to ensure even tiny micro-pores are caught. Sourcing teams use these observations to validate the parameters of the sealing equipment on the assembly line.
Quality Control
Passing this test guarantees that the cell can maintain its dry internal state during transportation and storage. It provides a simple method to check the reliability of the pouch seals before the batteries are integrated into larger packs. When seals fail the test, the thermal sealing parameters must be adjusted.
This action prevents the release of volatile compounds and protects subsequent assembly equipment from corrosive fluid contamination.