A method with battery state estimation may include: generating a plurality of electrochemical-thermal (ECT) models corresponding to modeling conditions based on an arbitrary parameter of an ECT model configured to perform modeling of a battery; determining a target parameter of the ECT model based on an error between an actual state of the battery and a model-derived state of the battery obtained by a parallel operation of the plurality of ECT models; and estimating a state of the battery based on the target parameter.