Vehicle State Estimation Apparatus and Operation Method Thereof

A vehicle state estimation apparatus includes a current sensor and a processor, wherein the processor may be configured to obtain a current profile of a battery pack of a vehicle via a current sensor, extract a low-frequency component of a predetermined frequency or less from the current profile, and estimate a first flat section in which a current value in the low-frequency component is equal to or greater than a first predetermined current value and a change in current is maintained less than or equal to a first threshold value over a predetermined period of time as a charging period of the battery pack.