Just to add some trivia to that question. Previously, the reserve teams were allowed to play Spanish Cup (Copa del Rey). In 1980, Castilla CF (Real Madrid's reserve team) played the final of that competition against Real Madrid. read more
So, since FC Barcelona play in La Liga, Barcelona B can be promoted only up to the Segunda Division. If (ever) the Barcelona first team is relegated to the Segunda Division, the B team may be allowed to move to La Liga (depending on their standing the Segunda Division, of course). read more
They have won second division before - Barcelona B is not allowed to get promoted to the First Division because of it's relationship to Barcelona. A youth team or development team of another team in La Liga is not allowed in La Liga. read more
Founded in 1970 as FC Barcelona Atlètic, it is the reserve team of FC Barcelona, and currently plays in Segunda División, holding home matches at the Mini Estadi. Reserve teams in Spain play in the same league system as the senior team, rather than in a reserve team league. read more