Meaning
Gas analyzer systems utilize four parallel metal rods to filter and measure ion beams based on their mass-to-charge ratios. In battery research and quality control, quadrupole mass spectrometry is used to identify the gases evolved during cell cycling or thermal runaway events. This provides a clear picture of the chemical reactions taking place inside the cell.
Analytical Detection
An RF voltage is applied to the rod pairs to select only specific ions that can pass through to the collector. The quadrupole mass spectrometry system scans across a range of mass-to-charge ratios, allowing for the detection of carbon dioxide, hydrogen and other volatile gases. This provides highly resolved analysis of the outgassing events during cell aging.
This data helps engineers to understand the degradation mechanisms of the cell.
Sourcing Application
Sourcing managers use results from this analysis to compare the electrochemical stability of different electrolyte formulations. Electrolytes that produce fewer decomposition gases under quadrupole mass spectrometry testing are selected for high-voltage cells. This ensures that the sourced chemistry will have a lower rate of gas generation, which reduces the risk of cell swelling.
This analysis is critical for selecting high-quality cell suppliers.
Operational Requirement
Ultra-high vacuum environments are required for the analyzer to operate without background noise. If the pressure in the system is too high, the ion beams will collide with background molecules, which distorts the mass spectra. This requires the use of reliable turbomolecular pumps and vacuum chambers.
Sourcing specs must specify the vacuum thresholds required to ensure the accuracy of the gas analysis.
