Meaning
Critical stress value at which small fragments begin to detach from a brittle material surface. In the context of ceramic separators or solid state electrolyte layers, the micro chipping threshold defines the point where mechanical handling causes physical loss of material. Exceeding this limit results in surface pits that act as points for dendrite growth.
Stress Limit
Tensile and compressive forces during manufacturing must stay below this value. When a roller applies too much pressure to a coated film, the micro chipping threshold is often reached at the edges. Overpressure creates fine debris that can contaminate the assembly area.
Maintaining the tension below the breaking point of the surface grains prevents this failure.
Production Impact
Throughput speeds are often limited by the fragility of the electrode coatings. If the machinery moves too fast, the vibration can cause the material to reach its micro chipping threshold through repeated contact with guides. Slower speeds or padded rollers help to keep the surface intact.
Yield rates improve when the process window is wide enough to avoid these mechanical fractures.
Failure Sequence
Damage usually starts at the grain boundaries of the material. Once the micro chipping threshold is crossed, the removal of one grain weakens the surrounding structure and leads to larger craters. These voids reduce the effective thickness of the separator layer.
Localized thinning increases the risk of a short circuit during the first charge cycle. The presence of loose particles also interferes with the wetting of the electrolyte and creates dry spots in the cell.
