A battery box assembly, comprising: a thermal management component configured to regulate temperature of a battery module; a frame fixed to an edge region of the thermal management component; a top cover covering the frame and forming, together with the frame and the thermal management component, a box for accommodating the battery module; a bottom protective plate fixed to the thermal management component in a direction away from the battery module and spaced from the thermal management component to form a sealed space; and an airflow pipeline arranged inside the box, wherein the airflow pipeline communicates with the sealed space on one end and communicates with the outside of the box on the other end; wherein the frame is provided with a balancing valve assembly allowing communication between the inside of the box and the outside of the box, wherein the airflow pipeline communicates with the outside of the box on the other end via the balancing valve assembly; and wherein the balancing valve assembly comprises a balancing valve body and a connector portion communicating with the balancing valve body, wherein the connector portion is embedded inside the frame, the balancing valve body extends out of the box, and the airflow pipeline communicates with the balancing valve body via the connector portion; characterized in that the balancing valve body comprises: a body portion, wherein the body portion comprises a bottom wall attached to an outer surface of the frame, an annular side wall bendingly extending from the bottom wall toward a direction leaving the frame and enclosing a chamber, a first opening made into the bottom wall and allowing the chamber to communicate with the connector portion, and a second opening enclosed by the annular side wall and opposite the first opening; a first sealing ring sandwiched between the outer surface of the frame and the bottom wall; a waterproof breathable film disposed inside the chamber and separating the first opening and the second opening on two opposite sides; a protective cover covering the second opening; and an air vent made into the annular side wall, wherein the air vent and the second opening are located on the same side of the waterproof breathable film. a thermal management component configured to regulate temperature of a battery module; a frame fixed to an edge region of the thermal management component; a top cover covering the frame and forming, together with the frame and the thermal management component, a box for accommodating the battery module; a bottom protective plate fixed to the thermal management component in a direction away from the battery module and spaced from the thermal management component to form a sealed space; and an airflow pipeline arranged inside the box, wherein the airflow pipeline communicates with the sealed space on one end and communicates with the outside of the box on the other end; wherein the frame is provided with a balancing valve assembly allowing communication between the inside of the box and the outside of the box, wherein the airflow pipeline communicates with the outside of the box on the other end via the balancing valve assembly; and wherein the balancing valve assembly comprises a balancing valve body and a connector portion communicating with the balancing valve body, wherein the connector portion is embedded inside the frame, the balancing valve body extends out of the box, and the airflow pipeline communicates with the balancing valve body via the connector portion; characterized in that the balancing valve body comprises: a body portion, wherein the body portion comprises a bottom wall attached to an outer surface of the frame, an annular side wall bendingly extending from the bottom wall toward a direction leaving the frame and enclosing a chamber, a first opening made into the bottom wall and allowing the chamber to communicate with the connector portion, and a second opening enclosed by the annular side wall and opposite the first opening; a first sealing ring sandwiched between the outer surface of the frame and the bottom wall; a waterproof breathable film disposed inside the chamber and separating the first opening and the second opening on two opposite sides; a protective cover covering the second opening; and an air vent made into the annular side wall, wherein the air vent and the second opening are located on the same side of the waterproof breathable film. a body portion, wherein the body portion comprises a bottom wall attached to an outer surface of the frame, an annular side wall bendingly extending from the bottom wall toward a direction leaving the frame and enclosing a chamber, a first opening made into the bottom wall and allowing the chamber to communicate with the connector portion, and a second opening enclosed by the annular side wall and opposite the first opening; a first sealing ring sandwiched between the outer surface of the frame and the bottom wall; a waterproof breathable film disposed inside the chamber and separating the first opening and the second opening on two opposite sides; a protective cover covering the second opening; and an air vent made into the annular side wall, wherein the air vent and the second opening are located on the same side of the waterproof breathable film.