Meaning
Destructive physical examination of a degraded or failed electrochemical cell under controlled environmental conditions establishes the root cause of capacity loss, impedance growth, or physical damage. Performing battery post-mortem analysis requires harvesting cells from modules, discharging them to safe voltage thresholds, and dismantling the casing inside an inert atmosphere glovebox. This diagnostic process measures active material dissolution, separator tearing, lithium plating, and electrode delamination.
The boundary of this evaluation begins after non-destructive electrical diagnostics finish and ends when chemical, structural, and morphological characterization of all harvested components concludes.
Analytical Procedure
Dismantling cell structures occurs inside argon filled containment chambers to prevent reaction between ambient oxygen, moisture, and reactive lithium compounds. Executing battery post-mortem analysis involves sectioning the current collectors, separator layers, and electrode coatings for sub-micron imaging and spectroscopy. Solvents wash away residual electrolyte salts from harvested electrode samples to prepare them for solid state surface evaluation.
Scanning electron microscopes record cross sectional images of active particles to identify microcracking and surface coating degradation. X-ray diffraction measures changes in electrode lattice parameters that correlate with loss of lithium inventory over extended cycling history. Inductively coupled plasma atomic emission spectroscopy determines transition metal dissolution rates from cathode materials into liquid electrolyte mixtures.
Degradation Verification
Observed physical alterations in extracted materials are matched against recorded electrical performance logs from cycle testing. Applying battery post-mortem analysis differentiates between active lithium loss and passive degradation of conductive carbon networks within composite electrodes. Thickness measurements on harvested negative electrodes reveal the spatial distribution of solid electrolyte interphase growth and metallic lithium deposition.
Differential scanning calorimetry on extracted components assesses thermal stability changes resulting from high voltage operational exposure. Chemical characterization of isolated gas samples identifies decomposition pathways of organic carbonates under abnormal voltage conditions.
Evidence Preservation
Chain of custody protocols protect harvested samples from atmospheric exposure and mechanical damage during transfer between analytical instruments. Conducting battery post-mortem analysis provides legal and technical evidence for warranty disputes, manufacturing quality claims, and field failure investigations. Sealed transfer containers filled with inert gas prevent oxidation of air sensitive anode surfaces during transport to electron microscope facilities.
Standardized photographic records document mechanical deformation, corrosion, and melting before microstructural characterization proceeds. Physical samples remain stored in controlled environments to allow independent re-evaluation by third party forensic laboratories.
