HVIL (High-Voltage Interlock Loop)
Definition
A safety circuit that monitors the physical integrity of all high-voltage connections. If any HV connector is disconnected, the HVIL circuit opens, triggering immediate system shutdown.
Why It Matters
- Prevents arc flash hazards during maintenance or connector disconnect
- Required safety feature for systems above 60V DC
- Provides hardware-level safety independent of software
- Industry standard for high-voltage battery safety architecture
Common Pitfalls
- Not implementing HVIL on all HV connectors (leaving safety gaps)
- Using high HVIL loop current (increases connector requirements)
- Not fail-safe design (HVIL should default to open/safe state)
- Ignoring connector contact resistance in HVIL loop