A cell retainer assembly (130) for a battery powered, outdoor power equipment device includes a plurality of cell reception slots (140) configured to receive and retain respective ones of battery cells (120) and a plurality of cell retention structures (180). At least some of the cell reception slots (140) are formed by corresponding ones of the cell retention structures (180). At least one cell retention structure (180) are configured to extend around a periphery of a portion of a corresponding battery cell (120) inserted therein. The cell retention structure includes a series of cell engaging portions (184) separated from each other by respective spacing portions (188). The at least one cell retention structure (180) may be formed of flexible material.