Meaning
High-sensitivity gas detection technique measures the rate of tracer gas escape from a sealed battery cell to verify its hermetic integrity. Implementing helium mass spectrometry leak testing ensures that volatile organic solvents cannot escape the cell housing and that moisture cannot enter. The process involves evacuating the chamber containing the pressurized cell and analyzing the surrounding atmosphere for the presence of the tracer gas.
It represents the industry standard for high-volume quality control.
Process Execution
Placing the cell in a vacuum chamber is the first step in the dry testing or wet testing sequence. In a typical dry test, the empty cell casing is evacuated and connected to the mass spectrometer while helium is sprayed externally. For completed cells, the housing is filled with a mixture containing helium during the final sealing step, or the cell is placed in a pressurized helium chamber to force gas through any existing pathways before it is analyzed.
Sensitivity Limit
Extremely low leak rates down to one millionth of a cubic centimeter per second can be detected with this equipment. This level of precision is necessary because even microscopic gaps can allow enough moisture ingress over several years to degrade the cell chemistry. The mass spectrometer is tuned specifically to the atomic mass of helium to eliminate false positives from ambient gases.
Production Integration
Automated testing chambers are integrated directly into the assembly line to scan every cell before packaging.
