Helium Mass Spectrometry for Micro Leak Detection in Battery Envelopes
Inline helium mass spectrometry detects sub-micron battery envelope leaks down to 10-8 mbar l/s, preventing moisture-induced HF corrosion and solvent loss.
Accumulation Chamber
Meaning
Sealed test volumes isolate a manufactured component to gather escaping tracer gas over a specified duration. In battery cell manufacturing, an accumulation chamber provides a controlled space to detect micro-leaks in the cell housing or seal. The method measures the rising concentration of helium or electrolyte solvent vapor under atmospheric pressure to determine the total leakage rate before the cell enters final assembly.
Measurement Mechanism
Gas sensors or mass spectrometers monitor the internal atmosphere of the enclosure continuously. The rate of tracer gas concentration increase correlates directly with the defect size in the cell casing. This approach avoids the complex vacuum systems required for high-vacuum chamber testing.
Leak Evaluation
Operators place cells inside the sealed volume and inject a tracer gas or rely on internal electrolyte volatility. If a cell contains a defect, the escaping gas rises in the surrounding airspace and is carried to the sensor by a recirculating carrier gas. The system then calculates the leakage rate by analyzing the signal drift over time.
Chamber Boundary
Atmospheric testing faces sensitivity limitations due to the natural background level of tracer gases in the ambient environment. Extreme micro-leaks below a certain threshold require high-vacuum alternatives instead. The process remains highly effective for high-throughput automated sorting lines.