BATTERY PACK AND ELECTRICAL DEVICE

A battery pack includes a first battery cell, a second battery cell, and a third battery cell. A positive electrode active substance of each battery cell is composed of lithium iron phosphate and a low-temperature additive. The low-temperature additive is selected from compounds containing at least two carbonyl groups, which are conjugated with an unsaturated structure or an atom having lone-pair electrons connected with the carbonyl groups, and a discharging cut-off voltage of the battery pack at a low temperature has the following rules: discharging cut-off voltages V, V, and V of the first battery cell, second battery cell, and third battery cell range from 1.95V to 2.1V, from 1.8 V to 2.0V, from 1.6V to 1.9V, respectively, and V, V, and V satisfy a relationship of V>V>V