Neither EVs nor ICE cars spontaneously combust unless there's a design flaw. Even when this happens it tends to be very rare, but the Chevy Bolt fires for example were fixed with a recall. Similarly a Ford recall last year fixed a problem where fuel injectors could leak and cause an engine fire.

EVs and ICE cars can both catch on fire in a bad enough accident, but this is true regardless of the age of the vehicle, and tends to be more sudden and violent with gasoline explosions vs battery fires.