Device and method for estimating state of battery

A device of estimating a balance state-of-health of a battery, the device comprising:

• a battery management system configured to measure voltage values of a plurality of cells constituting the battery;
• a memory configured to load a program for estimating the balance state-of-health of the battery in its entirety based on a state-of-health (SOH) of the battery and a state-of-balance (SOB) by voltage, wherein the SOH is a remaining capacity of the battery in its entirety, and the SOB by voltage is determined based on a voltage balance state of the voltage values of the plurality of cells of the battery measured by the battery management system;
• and
• a processor configured to execute instructions included in the program loaded by the memory,
• wherein according to executing of the program, the processor is configured to:
• set a voltage difference allowable limit value less than or equal to a voltage difference between a fully charged-state voltage and a discharged-state voltage of the battery,
• set an allowable limit quantile value based on which an allowable voltage limit range determined based on the voltage difference allowable limit value with respect to an average voltage value is subclassified into one or more analysis sections, the average voltage value being calculated based on the voltage values of the cells measured by the battery management system,
• determine a quantile drop rate based on the allowable limit quantile value, the quantile drop rate being a voltage drop rate in the allowable voltage limit range with respect to the average voltage value,
• determine a quantile degree, which is a degree of one of the analysis sections in which the voltage values measured for each cell are all included within a voltage range of the one of the analysis sections for a first time,
• determine the SOB by voltage based on the quantile drop rate and the quantile degree,
• estimate and output the balance state-of-health of the battery in its entirety based on the voltage balance state of the battery by applying the SOB by voltage to the SOH of the battery such that the balance state-of-health and the SOH for the battery in its entirety at a voltage measurement point in time are different from each other based on a difference between the voltage values of the plurality of cells, and
• stop charging and discharging of the battery based on the balance state-of-health of the battery in its entirety.