Upgrading KamLAND-Zen for improved sensitivity to neutrinoless double-beta decay

KamLAND is a 1 kton liquid scintillator antineutrino detector located underground in Kamioka, Japan. The KamLAND-Zen experiment began in 2011, using KamLAND to search for neutrinoless double-beta decay ($0\nu\beta\beta$). This process, if observed, would indicate that neutrinos are their own antiparticle and thus are Majorana fermions, a discovery that could help explain the matter-antimatter discrepancy in our universe. Currently, KamLAND-Zen is one of the most sensitive experiments to $0\nu\beta\beta$. In order to improve upon the present limits for $0\nu\beta\beta$, KamLAND is undergoing a series of upgrades to reduce background. This includes the construction of a new inner nylon chamber (``mini-balloon''). The current results and design considerations for the mini-balloon will be discussed.