Overcharge
Definition
Condition where a lithium-ion cell voltage exceeds its maximum safe voltage, causing electrolyte decomposition, lithium plating, gas generation, and potential thermal runaway.
Why It Matters
- Leading cause of lithium-ion battery fires
- Causes permanent capacity loss even if thermal runaway avoided
- Prevention requires both BMS and charge control redundancy
- Testing overcharge scenarios required for safety validation
Common Pitfalls
- Single-fault vulnerability (no redundant overcharge protection)
- Not testing overcharge protection under all operating conditions
- Inadequate margin between nominal end-of-charge and protection voltage
- Not considering voltage measurement accuracy in protection thresholds