When the Battery Dies, So Does Everything Else
An incident involving a Cadillac Lyriq electric vehicle has highlighted a potential safety gap in modern EV design that is receiving renewed scrutiny. When the Lyriq's battery discharged completely, the vehicle's electrical systems went offline—including the electronic door locks—leaving a baby stranded inside the car until emergency responders were able to access the vehicle. The incident raises questions about how EVs should be designed to maintain critical safety functions even when the traction battery is fully depleted.
The Difference Between EVs and Traditional Cars in a Dead-Battery Scenario
Internal combustion vehicles have a clear hierarchy of electrical systems. The 12-volt auxiliary battery handles door locks, windows, and interior electronics, and is completely separate from the engine's cranking function. A car with a dead starter battery can still have its doors unlocked manually via a physical key or by jumping the 12-volt battery. Even if both the engine and the auxiliary battery fail simultaneously—an extraordinarily rare scenario—most traditional vehicles have mechanical door lock overrides accessible from inside the cabin.
Electric vehicles complicate this architecture. While many EVs do include a small 12-volt auxiliary battery for low-voltage systems, the relationship between the traction battery and auxiliary systems varies significantly across manufacturers and models. In some configurations, a completely depleted traction battery can take the auxiliary battery offline with it, or prevent it from being charged. The result is a vehicle where every electrical system—including door locks—becomes unresponsive simultaneously.
