No, that's why I asked. I have not looked but there may be some recommendation in the manual for an acceptable storage temperature range for batteries.
Just as a guess I would say what's comfortable for us Humans.
So I would hazard a guess and say set the fridge to the highest setting you can to save energy and still keep the batteries cool.
Unless you plan to use it to keep drinks cool too but too cold is probably as bad for batteries as too hot.
Just found this:
How to Safely Store Lithium Ion Batterieshttps://www.uschemicalstorage.com/how-to-store-lithium-batteries/So looks like 59°F(15°C) is the place to be but they recommend following the manufacturers guidelines of course.
From a Festool cordless tool manual. I would imagine they all read about the same.
"Store in a cool, dry place at a temperature between 5 °C and 25 °C."