Yes, Millo blender can be used both ways - when plugged in or without a cord.
When it is plugged in, it is automatically charging batteries and you are able to see that in App battery indication is green color:
or on blender it self, when you press once manual power on button and then LED indication will show you how much batteries are charged and blinking two LED's shows that it is charging right now.
If Millo blender is unplugged, then it is working from batteries, up to 10 smoothies, depends what kind of recipes and what type of ingredients you will use. After each smoothie App will show you battery status, so you will know how many smoothies you can still make on batteries alone.