Rechargeable battery monitoring and control is provided using a non-linear rate-of-change failure threshold. A non-linear rate-of-change failure threshold is obtained indicative of an operational state abnormality in a rechargeable battery cell, and during the operational state of the rechargeable battery cell, a control compares an actual voltage rate-of-change of the rechargeable battery cell to the non-linear rate-of-change failure threshold. Based on the actual voltage rate-of-change of the rechargeable battery cell exceeding the non-linear rate-of-change failure threshold, the control identifies the operational state abnormality in the rechargeable battery cell. Based on identifying the operational state abnormality in the rechargeable battery cell, the control discontinues the operational state of the rechargeable battery cell.