Hi RR NDB
To make your conclusion requires the circuit breaker to have failed. That is unlikely.
To make your conclusion requires the geometry of the deficit to resemble other melted events, which it does not.
The geometry resembles, clearly, the action of a gas Jet, not a fusing failure.
Look again at the deficit on the top of the Battery. It too is shaped in a triangular, wedge form, suggesting an explosive escape of typical gas flares from this type of battery.
If the Thales designed system worked (I think it did), there would have been no battery voltage available to separate the connecting bar.
This damage is from Thermal runaway; the entire design is structured to avoid the type of event you describe.
I also believe the quantity of heat necessary to so seriously corrupt that connector is not available via Battery voltage alone.
Occam is our friend?