Hi,
inetdog:
...a large part of the connector appears to be totally missing, not just cut. That is more consistent with a high amperage vaporization of the metal than with a gas jet cut...
What´s remarkable is:
Screw just disappeared. Section of strap too.
The model is:
Short to ground (a fact) discharged (fortunately) the battery (reducing thermal runaway risks and duration) and this high (1,000 Amps +) current opened the battery (Voltage recorded, after fluctuation, went to zero)
...although both events may have occurred as slightly different times.
Fact is: 5 Kg of the battery, gone. (electrolyte)