Aren’t Lithium Primaries compatible with everything AA/AAA?

  • Yes

If a flashlight takes 14500 or 10440 does this mean it can safely handle Lithium Primaries?
-No problem as long as the driver can accept 1,2-1,7V. Best way to know is totry it, no chance in harming your lights, the worst that can happen is that there will not be enough power to light up

How much safer are Lithium Primaries compared to 3.7V lithium batteries like 18650 etc?
— AFAIK, they might be the safest battery to use and store-
EDIT: Didn’t tought about the reactive aspect, was referring to the fact that since they can’t be recharged, a lot of potential problems are avoided

Can you leave them in a car under the scorching sun?
-heat and any type of battery is never a good mix altough lithium battery can endure more heat than a lot of other chemistry

Will they leak?
-not supposed to

Can they shortcircuit when loose in your bag?
-yes, like any battery with exposed contacts