The invention discloses an electrochemical battery maintaining oxygen concentration by air recirculation and a method for operating the same. The electrochemical battery includes: a battery module comprising at least one electrochemical cell; an air supplier configured to supply air to the battery module and constantly maintain an oxygen concentration in the air that is supplied to the battery module; and an air recirculator configured to recirculate air exhausted from the battery module, wherein the battery module comprises an air inlet port though which air is introduced from the air supplier, and an air outlet port through which air remaining after a reaction in the at least one electrochemical cell is exhausted, and wherein the air recirculator is configured to recirculate the air exhausted through the air outlet port of the battery module to the air inlet port of the battery module.