Earlier quoted context omitted.
Nearly all EV's today would run just fine on 3.7 volts fewer. My car's high voltage circuitry seems to work down to about half of the nominal voltage.
Is the failure mode of whatever chemistry is in an EV that they just conduct electricity? Li-Po usually fail in more spectacular ways than so.
Yes, this happens sometimes.
Search this page for "PTC": https://www.electricbike.com/inside-18650-cell/
The PTC protects the rest of the battery if a single cell internally fails short.