Doesn’t excommunication send a person to hell?

No. The intention of an excommunication is just the opposite. It is intended to show the person that he is outside the communion of the Church and that he must turn away from the wrong he is committing and be reconciled. Christ said he came to save, not to condemn. Christ gave us the sacraments to bring us to heaven. It is these sacraments the Church wishes the excommunicated would return to.