There are certain lithium mixtures that will not let a 'cold' battery release very much power. The chemical reaction of the lithium cell happens at temperature (remember all the 'stuck' Tesla's last January?) and a cold battery has little power. "Cold" is a relative term, determined by the individual battery's design (or construction, or lithium chemistry used).
Here's something you might try, which comes from old oilfield experience:
When coming to the bike, turn the key on and turn on the headlight for 3-5 seconds (maybe 10) before trying to start it. The discharge, if it have enough surface electrons available, will warm the individual cells very quickly. Then the chemistry will start, bringing up the free electrons you need.
In the oilfield, when our trucks would be in sub-zero (WAY sub, like -30 degrees F or more) for the night before, we would climb into the cabs and turn on all the lights on the truck, marker lights, spotlights, etc. Then about 45-60 seconds later the engines could turn over fast enough to start. If we just tried to jump in the cabs and start them, they turned over too slowly and flooded the engines with diesel, making them REAL hard to start, if at all. The discharge will fire up the chemistry in the lithium battery: you might have to experiment with the 'start delay' time to make it optimum.
