Storing lithium-ion batteries in cold condition is no problem (even if there are myths that say so).
The only problem is that "electron flow" is much slower, means charging or decharging (=using/riding with motor support). Charging can be very slow with a frozen battery or even harm the battery, but the solution is easy. Do not charge in the morning before your trip after leaving the battery in a long&cold night. Charge directly after a ride, when battery is warm and it'll stay warm during charging, even if it's freezing outside. With decharging/riding with a full but frozen battery it depends on size of the battery and the load you try to squeeze out of it. You normally can't damage the battery here, but the maximum current the battery can give may be reduced until heated a little bit by the load. Creo's battery is quite small, but the load is as well, so I guess it will act like many other ebikes, where maximum support may be reduced with a really cold battery. Level1+2 of the SL drive should work fine I guess.
But I only know "german" standard, which means maximum maybe -15 till -10 degree Celsius outside in winter and maybe -5 or -8 for the battery in the garage. If we talk about -30 and -20 for the battery, this may be worse. But personally I can't ride bicycle or do sport outside below -10 degree Celsius...