Heating control method for energy storage, energy storage system, and photovoltaic energy storage system

An energy storage system, comprising:

• a controller, and
• a plurality of battery packs connected in parallel, a parallel connection point of the plurality of battery packs is connected to the controller or a direct-current bus, the battery pack comprises a cell pack, a temperature control module, a temperature sensing module, and a battery management system (BMS), the cell pack is electrically connected to the temperature control module and the BMS, the temperature sensing module is electrically connected to the BMS, the BMS is electrically connected to the controller, the temperature control module is configured to emit heat to increase a temperature of the battery pack, the temperature sensing module is configured to detect the temperature of the battery pack, the BMS is configured to receive, manage, and send information about the temperature, a current, a voltage, and an SOC of the battery pack, the controller is configured to receive a heating request of each of the plurality of battery packs and a state of charge (SOC) of each of the plurality of battery packs, the controller adjusts, based on a difference between a voltage of the direct-current bus and a charging voltage reference value of the energy storage system, a quantity N of battery packs whose temperature control modules are to be enabled, N is an integer greater than or equal to 1, and the controller determines, based on the SOCs of the plurality of battery packs, priorities for enabling the respective temperature control modules of the plurality of battery packs, and enables the temperature control modules of the N battery packs in the plurality of battery packs.

An energy storage system, comprising:

• an energy storage system including
• a controller, and
• a plurality of battery packs connected in parallel, a parallel connection point of the plurality of battery packs is connected to the controller or a direct-current bus, the battery pack comprises a cell pack, a temperature control module, a temperature sensing module, and a battery management system (BMS), the cell pack is electrically connected to the temperature control module and the BMS, the temperature sensing module is electrically connected to the BMS, the BMS is electrically connected to the controller, the temperature control module is configured to emit heat to increase a temperature of the battery pack, the temperature sensing module is configured to detect the temperature of the battery pack, the BMS is configured to receive, manage, and send information about the temperature, a current, a voltage, and an SOC of the battery pack, the controller is configured to receive a heating request of each of the plurality of battery packs and a state of charge (SOC) of each of the plurality of battery packs, the controller adjusts, based on a difference between a voltage of the direct-current bus and a charging voltage reference value of the energy storage system, a quantity N of battery packs whose temperature control modules are to be enabled, N is an integer greater than or equal to 1, and the controller determines, based on the SOCs of the plurality of battery packs, priorities for enabling the respective temperature control modules of the plurality of battery packs, and enables the temperature control modules of the N battery packs in the plurality of battery packs;
• and
• an inverter, the inverter comprises a DC/DC converter, a DC/AC converter, and a direct-current bus, the energy storage system is connected to the inverter by using the direct-current bus, the DC/AC converter is connected to a high-voltage direct-current side of the DC/DC converter, and the DC/AC converter is configured to implement bidirectional conversion between an alternating current and a direct current, so as to convert a direct current from the DC/DC converter or the energy storage system into an alternating current and transfer the alternating current to a power grid or a load, or convert an alternating current from a power grid into a direct current to charge the battery packs in the energy storage system.