It can be either. Officially, they are "The Black Eyed Peas," but someone saying, "Black Eyed Peas," is not incorrect.
The Black Eyed Peas took that name because black eyed peas are their favorite food.
because they say black eyed peas are food for the soul and the black eyed peas sing from their soul!
black eyed peas are beans,the Black eyed peas named themselves that because they said black eyed peas are soul food and their music comes from the soul.( true fact comment by Toni best )
Will.I.Am