A method for upgrading an energy storage system remotely, applied to an energy storage system, wherein the energy storage system comprises an energy management system, a battery management system, and a power conversion system, and the method for upgrading an energy storage system remotely comprises: receiving, by a communications gateway in the battery management system, a to-be-upgraded file sent by the energy management system, wherein the to-be-upgraded file is obtained by the energy management system; controlling, by the energy management system by using the power conversion system, the energy storage system to disconnect from high voltage when current operating status of the energy storage system allows a program upgrade, and detecting status of high voltage connection of the energy storage system by using the battery management system; and sending the to-be-upgraded file to the battery management system after receiving a notification sent by the battery management system about completion of disconnecting the energy storage system from high voltage; detecting a type of a to-be-upgraded node in the to-be-upgraded file; and performing the program upgrade on the to-be-upgraded node according to the type of the to-be-upgraded node by using the to-be-upgraded file; wherein the type of the to-be-upgraded node comprises the communications gateway; and the performing the program upgrade on the to-be-upgraded node according to the type of the to-be-upgraded node by using the to-be-upgraded file comprises: setting an update flag bit in a non-volatile memory of the communications gateway; copying upgrade data in the to-be-upgraded file to a designated area of the communications gateway after an upgrade request comprised in the to-be-upgraded file to upgrade the communications gateway is detected; verifying the upgrade data in the designated area after completion of copying the upgrade data; and running the upgrade data in the designated area of the communications gateway after the upgrade data in the designated area passes the verification, so as to complete the program upgrade for the communications gateway. receiving, by a communications gateway in the battery management system, a to-be-upgraded file sent by the energy management system, wherein the to-be-upgraded file is obtained by the energy management system; controlling, by the energy management system by using the power conversion system, the energy storage system to disconnect from high voltage when current operating status of the energy storage system allows a program upgrade, and detecting status of high voltage connection of the energy storage system by using the battery management system; and sending the to-be-upgraded file to the battery management system after receiving a notification sent by the battery management system about completion of disconnecting the energy storage system from high voltage; detecting a type of a to-be-upgraded node in the to-be-upgraded file; and performing the program upgrade on the to-be-upgraded node according to the type of the to-be-upgraded node by using the to-be-upgraded file; wherein the type of the to-be-upgraded node comprises the communications gateway; and the performing the program upgrade on the to-be-upgraded node according to the type of the to-be-upgraded node by using the to-be-upgraded file comprises: setting an update flag bit in a non-volatile memory of the communications gateway; copying upgrade data in the to-be-upgraded file to a designated area of the communications gateway after an upgrade request comprised in the to-be-upgraded file to upgrade the communications gateway is detected; verifying the upgrade data in the designated area after completion of copying the upgrade data; and running the upgrade data in the designated area of the communications gateway after the upgrade data in the designated area passes the verification, so as to complete the program upgrade for the communications gateway. setting an update flag bit in a non-volatile memory of the communications gateway; copying upgrade data in the to-be-upgraded file to a designated area of the communications gateway after an upgrade request comprised in the to-be-upgraded file to upgrade the communications gateway is detected; verifying the upgrade data in the designated area after completion of copying the upgrade data; and running the upgrade data in the designated area of the communications gateway after the upgrade data in the designated area passes the verification, so as to complete the program upgrade for the communications gateway.