A modular cell holder assembly includes a first cell holder member including a first cell receptacle and a second cell holder member including a second cell receptacle. The second cell holder member is connected with the first cell holder member forming a modular cell holder with the first cell receptacle and the second cell receptacle combining to form a cell receiving zone. A plurality of current connectors is provided on an outer surface of one of the first cell holder member and the second cell holder member. The plurality of current connectors is configured to establish a selected electrical configuration of energy storage cells in the cell receiving zone.