[amluto]

Speculation, since I’m not an expert:

The battery is big, so it has high thermal mass and lots of area for cooling. The motor is small. Motors can also easily be thermally limited. A permanent magnet motor that overheats will demagnetize and be destroyed. Induction motors and other non-permanent-magnet motors are less sensitive, but resistance goes up and metals and glues soften at higher temperature.