Would it be safe to sleep in a car?

me and my sister are going up to crivitz wisconsin in about a week (45 min from greenbay). my aunt currently lives in her guest house because her home burned down and there is no room for me inside so i have two options 1. to sleep in a tent or 2. in my car. im worried about bears and raccons and i would feel more comfortable in the car with the door locked but is it safer? i have heard animals can try to break into cars but if i take the food out of my car and lock the doors and close the windows will i be ok?