A battery pack assembly includes at least one battery cell and a terminal connector mechanism. The at least one battery cell has at least one terminal which includes a terminal engagement portion. The terminal connector mechanism has a retention member and a biasing member. The retention member has retention portion and is configured to move between an engaged position and a disengaged position. The biasing member is positioned between the housing and the retention member to bias the retention member towards the engaged position. In the engaged position, the retention portion of the retention member engages with the terminal engagement portion to inhibit movement of the terminal connector mechanism. In the disengaged position, the retention portion of the retention member is disengaged from the terminal engagement portion to permit movement of the terminal connector mechanism.