The energy storage container ‌ is a device that integrates battery, battery management system, power conversion system, thermal management system, control system and monitoring system. Its core principles include battery energy storage, power conversion and thermal management.

 1. Battery system: The core of the energy storage container is the battery system, usually using lithium battery packs. Lithium battery has the advantages of high energy density, high charge and discharge efficiency, and long cycle life. These battery packs are composed of multiple single cells in series and parallel to meet different voltage and capacity requirements. For example, in large-scale energy storage applications, thousands of individual batteries may be connected together to form a megawatt-hour level of energy storage capacity. The battery management system (BMS) is responsible for monitoring the voltage, temperature, current and other parameters of each battery to prevent the occurrence of abnormal conditions such as overcharge, overdischarge, and overheating of the battery, thereby extending the service life of the battery and ensuring the safe operation of the battery system ‌.

2. Power conversion system: Power conversion system (PCS) plays a key role in power conversion and control in energy storage containers. During the charging process, PCS converts the external input AC to direct current to meet the battery's charging requirements. For example, when electric energy is charged from the grid, the alternating current of the grid is rectified by the PCS and becomes direct current that conforms to the charging voltage and current characteristics of the battery pack. During the discharge process, PCS converts the direct current output from the battery into alternating current, so that the energy can be fed back to the grid or supplied to the local load. PCS can also adjust the frequency, voltage and other parameters of the output electric energy according to the demand of the power grid or the change of the load, to ensure that the quality of the output electric energy meets the requirements ‌.

 3. Thermal management system: Since the battery generates heat during charging and discharging, the thermal management system is crucial for the stable operation of the storage container. The thermal management system mainly consists of cooling fans and liquid cooling pipes. When the temperature of the battery rises, the cooling fan will start and dissipate the heat by means of air convection. In systems with liquid cooling technology, the coolant circulates through the pipes, taking away the heat generated by the battery. The thermal management system can control the working temperature of the battery in a suitable range, the best working temperature of the general lithium battery is between 15-35 ℃, which can ensure the performance and life of the battery ‌.

 4. Other key components:control system ‌ : responsible for the operation and management of the entire energy storage container, including the coordinated control of the battery system, PCS and thermal management system. It controls the various subsystems according to preset operating policies, such as charging policies and discharge policies ‌.

 monitoring system ‌ : real-time monitoring of various operating parameters of energy storage containers, such as SOC (state of charge), SOH (health status) of batteries, input and output of PCS ‌.

 Fire and safety system ‌ : usually equipped with an independent fire control system, including smoke alarm, fire extinguisher and gas extinguishing device, to prevent the occurrence of fire accidents, ensure the safety of equipment and personnel ‌.