Meaning
Pressure-sensitive safety diaphragms integrated into cell caps or pack enclosures rupture at a designated pressure to release accumulated gases safely. A burst disc prevents the steel or aluminum casing of a battery from exploding when internal pressures rise due to off-gassing. It provides a non-reclosing relief path that bypasses standard electrical terminal seals.
This mechanical fail-safe represents the last line of physical defense against cell casing rupture.
Rupture Mechanism
Under normal operating conditions, the metallic sheet remains intact and holds the cell hermetically sealed. When internal temperature rises, electrolyte vaporization generates rapid gas buildup. The burst disc experiences tensile stress until the material reaches its ultimate tensile strength and tears open.
This design operates purely on pressure differentials, meaning it requires no sensor or electronic actuator.
Material Choice
Aluminum foil or stainless steel alloys are selected for their predictable mechanical failure thresholds. The thickness and pattern of the pre-scored lines on the burst disc govern the precise actuation pressure. This component must resist chemical corrosion from electrolyte vapors over a ten year service life.
If the material degrades prematurely, the cell may leak.
Procurement Audit
Cell buyers verify the statistical distribution of the rupture point. Batches with wide variance are rejected immediately.
