The present invention provides a unit cell for a nickel-zinc battery in the form of a cell pack having positive and negative electrodes reliably separated by a hydroxide ion-conductive separator, which can be readily handled and is very advantageous for forming an assembled battery. The nickel-zinc cell pack of the invention includes: a flexible bag comprising flexible films; a separation sheet liquid-tightly connected to the interior of the flexible bag to separate a positive-electrode chamber and a negative-electrode chamber for inhibiting liquid communication therebetween; a positive electrode and a positive-electrode electrolytic solution disposed in the positive-electrode chamber; a negative electrode and a negative-electrode electrolytic solution disposed in the negative-electrode chamber, wherein the separation sheet comprises a separator structure comprising a separator exhibiting hydroxide-ion conductivity and water impermeability.