A power control apparatus for protecting a secondary battery from overheat comprising: a sensing unit configured to measure a temperature of a battery cell, an outside air temperature around the battery cell and a load current; an adjusting unit configured to adjust power supplied from the battery cell to a load; and a control unit configured to: - estimate a future temperature change trend of the battery cell based on the temperature of the battery cell, the outside air temperature around the cell and the load current measured by the sensing unit, using Equation 1: m ⋅ C p dT dt = 1 − k I 2 ⋅ R cell + T environment − T R th _ environment m: battery cell mass (kg) C p: specific heat of cell (J/kg·K) T: cell temperature (°C) t: time k: derating factor I: current R cell: internal cell resistance (Ω) T environment: outside air temperature around cell (°C) R th_environment: thermal resistance between cell and environment (K/W); - analyze the estimated future temperature change trend of the cell and determine whether the future temperature of the battery cell diverges or converges, wherein the control unit is further configured to, when the future temperature is determined to converge to a convergence temperature (T sat): - calculate a convergence time (Δt sat) required for the temperature of the battery cell to converge by using Equation 1; - when the convergence temperature of the battery cell is higher than or equal to a limit temperature (T limit) and the convergence time is less than or equal to a reference time (Δt ref), to control the adjusting unit to reduce the power supplied from the battery cell to the load; and - when the convergence temperature of the battery cell is less than the limit temperature or the convergence time exceeds the reference time, not to proceed with power derating of the battery cell. a sensing unit configured to measure a temperature of a battery cell, an outside air temperature around the battery cell and a load current; an adjusting unit configured to adjust power supplied from the battery cell to a load; and a control unit configured to: - estimate a future temperature change trend of the battery cell based on the temperature of the battery cell, the outside air temperature around the cell and the load current measured by the sensing unit, using Equation 1: m ⋅ C p dT dt = 1 − k I 2 ⋅ R cell + T environment − T R th _ environment m: battery cell mass (kg) C p: specific heat of cell (J/kg·K) T: cell temperature (°C) t: time k: derating factor I: current R cell: internal cell resistance (Ω) T environment: outside air temperature around cell (°C) R th_environment: thermal resistance between cell and environment (K/W); - analyze the estimated future temperature change trend of the cell and determine whether the future temperature of the battery cell diverges or converges, wherein the control unit is further configured to, when the future temperature is determined to converge to a convergence temperature (T sat): - calculate a convergence time (Δt sat) required for the temperature of the battery cell to converge by using Equation 1; - when the convergence temperature of the battery cell is higher than or equal to a limit temperature (T limit) and the convergence time is less than or equal to a reference time (Δt ref), to control the adjusting unit to reduce the power supplied from the battery cell to the load; and - when the convergence temperature of the battery cell is less than the limit temperature or the convergence time exceeds the reference time, not to proceed with power derating of the battery cell. - estimate a future temperature change trend of the battery cell based on the temperature of the battery cell, the outside air temperature around the cell and the load current measured by the sensing unit, using Equation 1: m ⋅ C p dT dt = 1 − k I 2 ⋅ R cell + T environment − T R th _ environment m: battery cell mass (kg) C p: specific heat of cell (J/kg·K) T: cell temperature (°C) t: time k: derating factor I: current R cell: internal cell resistance (Ω) T environment: outside air temperature around cell (°C) R th_environment: thermal resistance between cell and environment (K/W); m: battery cell mass (kg) C p: specific heat of cell (J/kg·K) T: cell temperature (°C) t: time k: derating factor I: current R cell: internal cell resistance (Ω) T environment: outside air temperature around cell (°C) R th_environment: thermal resistance between cell and environment (K/W); - analyze the estimated future temperature change trend of the cell and determine whether the future temperature of the battery cell diverges or converges, - calculate a convergence time (Δt sat) required for the temperature of the battery cell to converge by using Equation 1; - when the convergence temperature of the battery cell is higher than or equal to a limit temperature (T limit) and the convergence time is less than or equal to a reference time (Δt ref), to control the adjusting unit to reduce the power supplied from the battery cell to the load; and - when the convergence temperature of the battery cell is less than the limit temperature or the convergence time exceeds the reference time, not to proceed with power derating of the battery cell.