Meaning
Metrological procedures quantify the evolution of gas in sealed battery cells by tracking changes in buoyant force while the unit is submerged in a reference fluid. An archimedes gas volume test provides a non-destructive way to measure internal pressure changes that occur during the formation process or throughout aging. The method stops at the boundary of the cell exterior and cannot distinguish between different chemical species of gas without secondary analysis.
Fluid Displacement
Buoyancy force acting on a submerged object relates directly to the volume of the displaced liquid. By applying an archimedes gas volume test, technicians detect volume increases as small as 0.01 milliliters.
Measurement Precision
High resolution scales are required to capture the subtle weight changes involved in this procedure. Using an archimedes gas volume test requires the use of a reference fluid with a known, stable density such as deionized water or specialized oils. Bubbles clinging to the surface of the cell will invalidate the results by creating false volume readings.
Gas Evolution
Chemical decomposition of the electrolyte often appears as swelling within the pouch or can. Data from an archimedes gas volume test help engineers determine if the solid electrolyte interface is stable or if secondary reactions are consuming the active material. When the rate of gas production exceeds a specific threshold, the cell is flagged for potential safety risks.
This measurement identifies the point at which mechanical deformation might lead to a breach of the cell housing.
