Battle points, also known as B points. Are a type of currency designed for the use of lowering the cost of euro capsules. They are awarded in the completion of daily challenges and when you get a "Lucky Shot".
Your count of Battle points are found next to your "Aeria Points" in the bottom left of the game screen. The icon is a capital "B" which is inside a silver circle.
In order to reduce the cost of a euro capsule, you will be required to have atleast 50. The price of each individual capsule will be lowered from 3000 euros, to 1000. Thus making the cost easier on your euros.
The MAXIMUM amount of BP a player is allowed to have is 1000 BP.