Use of a high capacity, closed phase, cryopreservation cell banking system for banking large volumes of cells, wherein the use comprises the following steps: a. connecting one of a plurality of high capacity cryopreservation bags to the high capacity, closed phase, cryopreservation cell banking system, wherein said plurality of cryopreservation bags each comprise features n to q below, and wherein the high capacity, closed phase, cryopreservation cell banking system comprises features i to m below; b. bringing a source of cells into fluid connection with the system; c. allowing the cells to come into fluid contact with the bags and to fill each bag to a desired capacity; d. aseptically thermo-sealing each of the inlet PVC tubes; e. withdrawing both the inlet tubing and the outlet tubing into each pouch; f. thermo-sealing each pouch to enclose and protect the PVC tubes and optional labeling; g. placing the bags into cassettes; and h. freezing the bags within their respective cassettes thereby banking the large volumes of cells, wherein the high capacity, closed phase, cryopreservation cell banking system comprises: i. a user interface for controlling and monitoring the dispensing of liquid biological materials into a plurality of cryopreservation bags; j. a plurality of cryopreservation bags; k. a plurality of fluid connections, adapted to fill the plurality of bags; l. a thermo-sealing means, for sealing tubing and bags; m. a plurality of metal cassettes for containing, freezing, storing & thawing the bags; further wherein said plurality of cryopreservation bags are each a high capacity cryopreservation bag, which is adapted for use in the high capacity, closed phase, cryopreservation cell banking system, and which is resistant to liquid nitrogen temperatures; and wherein said high capacity cryopreservation bag comprises: n. a first fluorinated ethylene propylene enclosure; o. at least one rigid FEP inlet conduit, in fluid connection with the first enclosure, and connectable to a first flexible sterile-weldable conduit which is PVC tubing; p. at least one rigid FEP outlet conduit, in fluid connection with the first enclosure, and connectable to a second flexible sterile-weldable conduit which is PVC tubing; and q. a FEP pouch, which is initially open at one end, and which is contiguous with the first enclosure, but thermosealed therefrom, and encircling both the rigid inlet conduit and the rigid outlet conduit, such that the pouch is neither in fluid communication with the first enclosure, nor the inlet nor outlet conduits; and wherein the pouch extends sufficiently far enough such that when the first enclosure has been filled with the biological material, the PVC tubes may be withdrawn into the pouch, which can then be thermosealed to form a second enclosure, which now contains both PVC tubes. a. connecting one of a plurality of high capacity cryopreservation bags to the high capacity, closed phase, cryopreservation cell banking system, wherein said plurality of cryopreservation bags each comprise features n to q below, and wherein the high capacity, closed phase, cryopreservation cell banking system comprises features i to m below; b. bringing a source of cells into fluid connection with the system; c. allowing the cells to come into fluid contact with the bags and to fill each bag to a desired capacity; d. aseptically thermo-sealing each of the inlet PVC tubes; e. withdrawing both the inlet tubing and the outlet tubing into each pouch; f. thermo-sealing each pouch to enclose and protect the PVC tubes and optional labeling; g. placing the bags into cassettes; and h. freezing the bags within their respective cassettes thereby banking the large volumes of cells, i. a user interface for controlling and monitoring the dispensing of liquid biological materials into a plurality of cryopreservation bags; j. a plurality of cryopreservation bags; k. a plurality of fluid connections, adapted to fill the plurality of bags; l. a thermo-sealing means, for sealing tubing and bags; m. a plurality of metal cassettes for containing, freezing, storing & thawing the bags; n. a first fluorinated ethylene propylene enclosure; o. at least one rigid FEP inlet conduit, in fluid connection with the first enclosure, and connectable to a first flexible sterile-weldable conduit which is PVC tubing; p. at least one rigid FEP outlet conduit, in fluid connection with the first enclosure, and connectable to a second flexible sterile-weldable conduit which is PVC tubing; and q. a FEP pouch, which is initially open at one end, and which is contiguous with the first enclosure, but thermosealed therefrom, and encircling both the rigid inlet conduit and the rigid outlet conduit, such that the pouch is neither in fluid communication with the first enclosure, nor the inlet nor outlet conduits; and wherein the pouch extends sufficiently far enough such that when the first enclosure has been filled with the biological material, the PVC tubes may be withdrawn into the pouch, which can then be thermosealed to form a second enclosure, which now contains both PVC tubes.