My experience is that cells don't like sub-zero storage.
I use Draegrsorb and have never had an issue with it. It is stored in the shed. In a cold winter we may see -25C on occasion. Just make sure the cannister and sorb charge are warm before the dive. This takes 4 or more hours for a couple of kilo in the cannister.
I have found that to do a dive to 40 mfw with a unit left in the boot overnight charged and ready in 0 C conditions is really not a bright idea.
Dale