If the sheet vinyl has cracked in the cold and the crack has now closed with warmer weather so that both sides of the crack are touching, you can repair the crack with vinyl seam sealer.
You will need the sealer and the dispenser bottle that distributes the sealer against the sides of the crack (it has a special applicator nozzle). AFAIK, seam sealer and the bottle are only sold at flooring installation distributors. Every large metro area has one of these stores.
Edit: I guess the big-box stores are now selling the
seam sealer and applicator