Acceptance Quality Limit Sampling Plans for Lithium Cell Receiving Facilities
Enforce ANSI ASQ Z1.4 Level II sampling with AQL 0.010 for critical safety flaws and Kelvin OCV IR screening to reject defective lithium cells at receiving dock.
Computed Tomography Inspection
Meaning
Non-destructive evaluation using computer-processed X-rays provides three-dimensional internal imaging of a battery cell. In the context of cell manufacturing, computed tomography inspection allows engineers to visualize electrode alignment and internal physical defects without damaging the housing. It provides high-contrast spatial mapping that reveals the placement of internal components relative to one another, proving especially useful for identifying cathode and anode overlap margins.
This non-invasive assessment remains highly reliable across various chemistries, giving a precise view of the wound or stacked electrodes.
Scanning Resolution
Spatial fidelity depends on the sample size and detector configuration during the imaging run. For small cylindrical or pouch cells, computed tomography inspection typically operates at micron-scale resolutions to capture sub-millimeter defects. This scan determines whether the electrode layers have drifted or warped.
Larger packs require longer scan times and suffer from lower resolution due to increased material density.
Defect Classification
Internal deviations are categorized by risk levels to determine whether the cell should be rejected. During computed tomography inspection, engineers can identify metallic particles, delamination, or electrode folding that could lead to an internal short circuit. This measurement directly influences the cell sorting process before final pack assembly.
Standard safety protocols rely on this structural imaging to isolate outlier cells.
Quality Verification
Manufacturing lines deploy these scans as part of root-cause analysis and quality auditing. While computed tomography inspection is too slow for 100 percent inline testing, it is the definitive reference during validation phases or failure investigations. It establishes the baseline against which high-speed ultrasonic or 2D X-ray systems are calibrated.