A high energy density battery module may comprise a plurality of battery units. The battery units may be electronically coupled to at least one other battery unit and may further comprise a plurality of electrochemical battery cells. The battery units may comprise a cell retainer to fix cells in a predetermined arrangement comprising a first and second column of battery cells. The battery units may comprise protective wrapping of thermally insulating material woven between at least a portion of the first and second column of battery cells. An electrical contact may be may be disposed in or on each of the plurality of battery units.