Energy storage system, battery self-heating control method, device and equipment and storage medium

Abstract

The embodiment of the invention provides an energy storage system, a battery self-heating control method, device and equipment and a storage medium. The energy storage system comprises a system controller, a switch module and a plurality of electric cabinets. One end of the switch module is connected with the high-voltage bus, and the other end of the switch module is connected with a connection point where the plurality of electric cabinets are connected in parallel; the system controller is in communication connection with the switch module and each electric cabinet. And the system controller is used for controlling the plurality of electric cabinets to form a charging and discharging loop under the condition that the plurality of electric cabinets meet the preset heating condition. When it is determined that the electric cabinet meeting the preset heating condition appears, the switch module is turned off, so that charging and discharging can be conducted between the electric cabinets, the alternating current flowing through the batteries in the multiple electric cabinets is formed, internal resistors of the batteries in the multiple electric cabinets are heated at the same time, the batteries in the multiple electric cabinets are heated at the same time, and the heating efficiency is improved.

Description

Energy storage system, battery self-heating control method, device, equipment and storage medium Technical Field

[0001] The present application relates to the field of battery technology, and in particular to an energy storage system, a battery self-heating control method, a device, a device, and a storage medium. Background Art

[0002] Some energy storage systems convert solar, wind, or nuclear energy into electricity and store it in batteries across multiple cabinets. For example, in a solar-storage system, photovoltaic (PV) sources convert solar energy into electricity and store it in batteries across multiple cabinets. Battery charge and discharge performance degrades significantly in low-temperature environments, significantly impacting the energy conversion performance of these energy storage systems. Therefore, battery heating is necessary in low-temperature environments.

[0003] In related technologies, a charging and discharging circuit is formed by a voltage converter in an electrical cabinet, capacitors on a high-voltage bus, and a power inverter connected to a load or a power grid. The battery and the capacitors on the high-voltage bus are alternately charged and discharged through the circuit, causing the internal resistance of the battery to heat up, thereby achieving the effect of heating the battery.

[0004] However, when the energy storage system has multiple electrical cabinets, the bus capacitor can only heat the batteries in each electrical cabinet in turn, which is very slow and inefficient.

[0005] Summary of the Invention

[0006] The embodiments of the present application provide an energy storage system, a battery self-heating control method, an apparatus, a device, and a storage medium, which perform charging and discharging between electrical cabinets, thereby heating batteries in multiple electrical cabinets at the same time and improving heating efficiency.

[0007] In a first aspect, an embodiment of the present application provides an energy storage system, including a system controller, a switch module, and a plurality of electrical cabinets;

[0008] The multiple electrical cabinets are connected in parallel, one end of the switch module is connected to the high-voltage bus, and the other end is connected to the connection point of the multiple electrical cabinets in parallel;

[0009] The system controller is respectively in communication with the switch module and each electrical cabinet;

[0010] The system controller is used to control the formation of a charging and discharging circuit between the multiple electric cabinets when there is an electric cabinet that meets the preset heating conditions among the multiple electric cabinets.

[0011] In this embodiment, a switch module is installed between each electrical cabinet and the high-voltage busbar in the energy storage system. When a cabinet meeting preset heating conditions is detected, a charge-discharge circuit is formed between the cabinets, allowing charging and discharging between the cabinets. This generates an alternating current flowing through the batteries in the multiple cabinets, causing the internal resistance of the batteries in the multiple cabinets to heat simultaneously. This achieves simultaneous heating of the batteries in multiple cabinets and improves heating efficiency.

[0012] In some embodiments, the electrical cabinet includes a battery, a battery management system, and a voltage converter;

[0013] The battery management system, the system controller and the voltage converter are all communicatively connected.

[0014] In this embodiment, the voltage converter in each electrical cabinet is electrically connected to a switch module and communicatively connected to a system controller. If a cabinet meeting preset heating conditions is detected, the switch module disconnects all cabinets from the high-voltage busbar, thereby forming a charge-discharge loop between the cabinets and enabling charging and discharging between the cabinets.

[0015] In some embodiments, the battery management system is used to detect the electrical parameters of the battery and transmit the electrical parameters to the system controller; the system controller is used to control the switch module to disconnect when it is determined that the electrical cabinet meets the preset heating conditions based on the electrical parameters.

[0016] In this embodiment, the battery temperature and battery charge are determined based on the battery's electrical parameters to determine whether they meet the preset heating conditions. This allows accurate identification of batteries requiring heating and prevents over-discharge caused by charging and discharging batteries with insufficient charge. If a battery is determined to meet the preset heating conditions, the switch module is controlled to disconnect, creating conditions for the subsequent formation of a charge-discharge circuit between multiple electrical cabinets, enabling inter-cabinet charging and discharging.

[0017] In some embodiments, the system controller is used to send a heating instruction to at least one electric cabinet when there is an electric cabinet that meets the preset heating conditions among the multiple electric cabinets, and the at least one electric cabinet includes the electric cabinet that meets the preset heating conditions; the at least one electric cabinet is used to construct a charging and discharging circuit between the electric cabinets based on the heating instruction, and control the batteries in the charging and discharging circuit to charge and discharge alternately.

[0018] In this embodiment, when it is determined that there is a battery that meets the preset heating conditions, a heating instruction is sent to the corresponding electric cabinet, so that the electric cabinet constructs a charge and discharge circuit including multiple electric cabinets based on the heating instruction, and alternately charges and discharges in the constructed charge and discharge circuit based on the heating instruction, thereby realizing charging and discharging between electric cabinets, and being able to heat multiple electric cabinets at the same time, thereby improving heating efficiency.

[0019] In some embodiments, the voltage converter includes at least one bridge arm having a flying capacitor and at least one energy storage element, and the bridge arm corresponds one-to-one to the energy storage element; one end of the energy storage element is connected to the positive pole of the battery in the electrical cabinet to which the voltage converter belongs, and the other end of the energy storage element is connected to the connection point of the upper bridge arm and the lower bridge arm in the bridge arm corresponding to the energy storage element.

[0020] In this embodiment, the voltage converter may be provided with a flying capacitor, and the number of bridge arms it includes may be one or more, so that the charging and discharging circuits between the electrical cabinets may have a variety of possible circuit structures.

[0021] In some embodiments, the voltage converter includes at least one bridge arm without a flying capacitor and at least two energy storage elements, and each bridge arm is connected to two energy storage elements respectively;

[0022] The bridge arm includes at least four switching tubes connected in sequence; the positive and negative poles of the battery in the electric cabinet to which the voltage converter belongs are respectively connected to the two energy storage elements connected to the bridge arm.

[0023] In this embodiment, the voltage converter may not have a flying capacitor, and may include one or more bridge arms, so that the charging and discharging circuits between the electrical cabinets may have a variety of possible circuit structures.

[0024] In a second aspect, an embodiment of the present application provides a battery self-heating control method, which is applied to the energy storage system described in the first aspect above, and the method includes:

[0025] Determining that there is at least one target electrical cabinet that meets a preset heating condition;

[0026] A plurality of electric cabinets including the target electric cabinet are controlled to form a charge-discharge loop, and batteries in the target electric cabinet are charged and discharged based on the charge-discharge loop.

[0027] In this embodiment, when an electric cabinet that meets the preset heating conditions is determined to have appeared, a charge-discharge circuit is formed between the multiple electric cabinets, so that charging and discharging can be performed between the electric cabinets, thereby forming an alternating current flowing through the batteries in the multiple electric cabinets, causing the internal resistance of the batteries in the multiple electric cabinets to heat up at the same time, thereby achieving simultaneous heating of the batteries in the multiple electric cabinets and improving heating efficiency.

[0028] In some embodiments, controlling multiple electrical cabinets including the target electrical cabinet to form a charge-discharge circuit includes:

[0029] Controlling the switch module to disconnect;

[0030] Determining a plurality of candidate electrical cabinets for forming a charge-discharge loop, wherein the plurality of candidate electrical cabinets include the target electrical cabinet;

[0031] The power devices in the voltage converters of the plurality of candidate electrical cabinets are controlled to be turned on and off, so as to form an alternating charging circuit and a discharging circuit.

[0032] In this embodiment, when a cabinet meeting preset heating conditions is detected, the switch module is disconnected, causing each cabinet to stop transmitting power to the grid and the energy storage to stop storing energy within the cabinet, thus paving the way for the subsequent establishment of a charge-discharge circuit between the cabinets. The system controller determines the cabinets that form the charge-discharge circuit and controls the on / off switching of the power devices in the voltage converters of these cabinets, forming a charge-discharge circuit between these cabinets. This enables charging and discharging between these cabinets, heats the internal resistance of the batteries in these cabinets simultaneously, and improves the efficiency of heating the batteries in multiple cabinets in the energy storage system.

[0033] In some embodiments, determining a plurality of candidate electrical cabinets for forming a charging and discharging loop includes:

[0034] Based on the electrical parameters of the batteries in the remaining electrical cabinets except the target electrical cabinet, determining the electrical cabinet that meets the preset charge and discharge conditions from the remaining electrical cabinets;

[0035] Select at least one electric cabinet from electric cabinets that meet preset charging and discharging conditions;

[0036] The target electric cabinet and the selected at least one electric cabinet are determined as a plurality of candidate electric cabinets for constituting a charge-discharge loop.

[0037] In this embodiment, at least one electric cabinet is selected from the electric cabinets that meet the preset charge and discharge conditions. Since the battery temperatures of the electric cabinets that meet the preset charge and discharge conditions are all higher than the preset low temperature threshold, the electric cabinets that meet the preset charge and discharge conditions are used to form a charge and discharge circuit with the target electric cabinet that needs to be heated. This helps to improve the efficiency of charging and discharging between the electric cabinets and further improve the heating efficiency of the batteries in multiple electric cabinets.

[0038] In some embodiments, controlling the on and off of power devices in the voltage converters of the plurality of candidate electrical cabinets to form alternatingly switched charging and discharging circuits includes:

[0039] Determining, based on the multiple candidate electrical cabinets, candidate electrical cabinets included in each of at least one charge-discharge circuit to be formed, wherein each charge-discharge circuit includes at least one target electrical cabinet that meets a preset heating condition;

[0040] The on and off of power devices of the voltage converters in the candidate electrical cabinets included in each charge and discharge circuit are controlled respectively to form an alternatingly switched charging circuit and discharging circuit in each charge and discharge circuit.

[0041] In this embodiment, the system controller determines the electrical cabinets included in each charging and discharging circuit to be constructed, and controls the on and off of the power devices of the voltage converters in the electrical cabinets included in each charging and discharging circuit, thereby realizing charging and discharging between the electrical cabinets in each charging and discharging circuit, and heating the batteries of multiple electrical cabinets at the same time.

[0042] In some embodiments, determining, based on the multiple candidate electrical cabinets, the candidate electrical cabinets included in each of the at least one charging and discharging circuit to be formed includes:

[0043] Determine that a charge-discharge loop is formed, divide the multiple candidate electric cabinets into a first electric cabinet group and a second electric cabinet group, and determine the first electric cabinet group and the second electric cabinet group as two groups of electric cabinets in the charge-discharge loop.

[0044] In some embodiments, determining, based on the multiple candidate electrical cabinets, the candidate electrical cabinets included in each of the at least one charging and discharging circuit to be formed includes:

[0045] Determine that multiple charge and discharge circuits are constituted, where the number of the multiple charge and discharge circuits is less than or equal to the number of the target electrical cabinets; divide the multiple candidate electrical cabinets into multiple groups of electrical cabinets, each group of electrical cabinets including at least two candidate electrical cabinets; and respectively determine the multiple groups of electrical cabinets as the candidate electrical cabinets included in each of the multiple charge and discharge circuits.

[0046] In this embodiment, the system controller can flexibly determine the electrical cabinets included in the charging and discharging circuits to be constructed, and then control the various charging and discharging circuits to alternately form charging circuits and discharging circuits based on the electrical cabinets included in the determined charging and discharging circuits, thereby achieving simultaneous heating of the batteries in the electrical cabinets included in each charging and discharging circuit, thereby improving heating efficiency.

[0047] In some embodiments, the separately controlling the on and off of power devices of the voltage converters in the candidate electrical cabinets included in each charge and discharge circuit to form alternatingly switched charging and discharging circuits in each charge and discharge circuit includes:

[0048] Sending a heating instruction to a voltage converter of an electrical cabinet in a first charge-discharge circuit, where the first charge-discharge circuit is any one of the charge-discharge circuits;

[0049] Based on the heating instruction, the first charge and discharge circuit is controlled to form a charging circuit and a discharging circuit that are alternately switched.

[0050] In this embodiment, the system controller sends a heating instruction to the voltage converters of the electrical cabinets in the first charge and discharge circuit, so that these voltage converters can control the on and off of their own power devices based on the heating instruction, thereby forming alternating charging circuits and discharging circuits in the first charge and discharge circuit, thereby achieving simultaneous heating of the batteries of each electrical cabinet in the first charge and discharge circuit, improving the heating efficiency, and increasing the temperature of the battery with too low a temperature and the charge and discharge performance of the battery.

[0051] In some embodiments, sending a heating instruction to a voltage converter of a power cabinet in the first charge-discharge circuit includes:

[0052] A heating instruction is sent to the voltage converter of each electrical cabinet in the first charge and discharge loop.

[0053] In this embodiment, the system controller can send a heating instruction to the voltage converter of each electrical cabinet in the first charge and discharge loop, so that the voltage converter of each electrical cabinet directly obtains the heating instruction, constructs the first charge and discharge loop according to the heating instruction, and controls the charging and discharging of each battery based on the heating instruction.

[0054] In some embodiments, sending a heating instruction to a voltage converter of a power cabinet in the first charge-discharge circuit includes:

[0055] A heating instruction is sent to a voltage converter of a target electrical cabinet in a first charge-discharge loop; and the heating instruction is forwarded to voltage converters of other electrical cabinets in the first charge-discharge loop via the voltage converter of the target electrical cabinet.

[0056] In this embodiment, the system controller can also send a heating instruction only to the voltage converter of the target electrical cabinet in the first charge-discharge loop. The voltage converter of the target electrical cabinet then forwards the heating instruction to the voltage converters of other electrical cabinets in the first charge-discharge loop. This provides another implementation for sending heating instructions, saving data traffic for the system controller.

[0057] In some embodiments, the first charge and discharge loop includes a first subset of electrical cabinets and a second subset of electrical cabinets, and the battery power corresponding to the first subset of electrical cabinets is greater than the battery power corresponding to the second subset of electrical cabinets;

[0058] The step of controlling the first charge-discharge circuit to form an alternating charging circuit and a discharging circuit based on the heating instruction includes:

[0059] Based on the heating instruction, in the first stage, a control is performed to form a circuit for charging the batteries of each electric cabinet in the first electric cabinet set to the batteries of each electric cabinet in the second electric cabinet set;

[0060] In the second stage, a control loop is formed for the batteries of each electric cabinet in the second electric cabinet set to charge the batteries of each electric cabinet in the first electric cabinet set.

[0061] In this embodiment, by controlling the on and off of the power devices in the voltage converter, the batteries in the first subset of electrical cabinets and the batteries in the second subset of electrical cabinets alternately charge each other, thereby achieving self-heating of the batteries in each electrical cabinet in the first charge and discharge loop and improving the battery heating efficiency.

[0062] In some embodiments, the first charge and discharge loop includes a first subset of electrical cabinets and a second subset of electrical cabinets, and the battery power corresponding to the first subset of electrical cabinets is equal to the battery power corresponding to the second subset of electrical cabinets;

[0063] The step of controlling the first charge-discharge circuit to form an alternating charging circuit and a discharging circuit based on the heating instruction includes:

[0064] Based on the heating instruction, in the first stage, a control is performed to form a circuit in which the batteries of each electric cabinet in the first electric cabinet subset respectively charge the energy storage elements of the voltage converters in the respective electric cabinets;

[0065] In the second stage, a circuit is formed by controlling the batteries of each electric cabinet in the first electric cabinet set and the energy storage element of the voltage converter to charge the batteries of each electric cabinet in the second electric cabinet set;

[0066] In the third stage, a control circuit is formed for the batteries of each electric cabinet in the second electric cabinet subset to charge the energy storage elements of the voltage converters in the respective electric cabinets;

[0067] In the fourth stage, a circuit is controlled to form in which the batteries of each electric cabinet in the second electric cabinet set and the energy storage elements of the voltage converter charge the batteries of each electric cabinet in the first electric cabinet set.

[0068] In this embodiment, by controlling the on and off of the power devices in the voltage converter, self-heating of the batteries in each electrical cabinet in the first charge and discharge loop is achieved, thereby improving the battery heating efficiency.

[0069] In some embodiments, the method further comprises:

[0070] When the number of batteries included in the first cabinet subset is greater than the number of batteries included in the second cabinet subset, the duration for which the first cabinet subset charges the second cabinet subset is controlled to be shorter than the duration for which the second cabinet subset charges the first cabinet subset.

[0071] In this embodiment, when the number of batteries included in the first subset of electrical cabinets is greater than the number of batteries included in the second subset of electrical cabinets, the problem of overcharging of the batteries in the second subset of electrical cabinets during the charging and discharging process can be avoided.

[0072] In some embodiments, the method further comprises:

[0073] Obtain the electrical parameters of the batteries in each electrical cabinet;

[0074] Based on the electrical parameters of the batteries in each electrical cabinet, it is determined whether there is a target electrical cabinet that meets the preset heating conditions.

[0075] In this embodiment, whether the battery meets the preset heating conditions is determined based on the battery's electrical parameters, and the battery that needs to be heated due to being too low in temperature can be accurately determined. The problem of battery over-discharge caused by charging and discharging the battery when the battery power is insufficient can also be avoided. The situation in which the charging and discharging process cannot be successfully completed due to a fault in the electrical cabinet can also be avoided.

[0076] In some embodiments, after charging and discharging the battery in the target electrical cabinet based on the charge-discharge circuit, the method further includes:

[0077] Based on the electrical parameters of the batteries in each electrical cabinet included in the charge-discharge circuit, determining whether a preset heating stop condition is met;

[0078] When it is determined that the preset heating stop condition is met, a heating stop instruction is sent to the voltage converter of the electrical cabinet in the charge-discharge circuit.

[0079] In this embodiment, during the charging and discharging process of the charge-discharge circuit formed between the electrical cabinets, a real-time determination is made as to whether a preset heating stop condition has been met based on the electrical parameters of the batteries in the electrical cabinets. When this condition is determined to have been met, the charge-discharge circuit is promptly controlled to stop charging and discharging. This avoids safety issues caused by continued charging and discharging when the battery temperature is abnormal, and also prevents excessive battery temperature from being caused by continued charging and discharging after the battery has reached the preset required temperature.

[0080] In a third aspect, an embodiment of the present application provides a battery self-heating control device, which is applied to the energy storage system described in the first aspect, and the device includes:

[0081] A determination module, configured to determine whether there is at least one target electrical cabinet that meets a preset heating condition;

[0082] The heating module is used to control multiple electric cabinets including the target electric cabinet to form a charge-discharge loop, and to charge and discharge the battery in the target electric cabinet based on the charge-discharge loop.

[0083] In a fourth aspect, an embodiment of the present application provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method described in the second aspect is implemented.

[0084] In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method described in the second aspect is implemented.

[0085] In a sixth aspect, an embodiment of the present application provides a computer program product, including a computer program, which is executed by a processor to implement the method described in the second aspect.

[0086] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0088] FIG1 is a circuit structure diagram of a charge and discharge circuit in which a battery is located in an energy storage system in the related art.

[0089] FIG2 is a schematic structural diagram of an energy storage system in related art.

[0090] FIG3 is a schematic structural diagram of an improved energy storage system according to an embodiment of the present application based on FIG2 .

[0091] FIG4 is a schematic structural diagram of an energy storage system provided in an embodiment of the present application.

[0092] FIG5 is another structural diagram of an energy storage system provided in an embodiment of the present application.

[0093] FIG6 is another structural diagram of an energy storage system provided in an embodiment of the present application.

[0094] FIG7 is a circuit diagram of a voltage converter with a flying capacitor provided in an embodiment of the present application.

[0095] FIG8 is a circuit diagram of a voltage converter without a flying capacitor provided in an embodiment of the present application.

[0096] FIG9 is a flow chart of a battery self-heating control method provided in an embodiment of the present application.

[0097] FIG10 is a schematic diagram of a circuit structure of a photovoltaic storage system provided in an embodiment of the present application.

[0098] FIG11 is a circuit diagram of a charging and discharging circuit between two electrical cabinets provided in an embodiment of the present application.

[0099] FIG12 is a schematic diagram of current flow when the battery 1 charges the inductor in the charge-discharge circuit shown in FIG11 .

[0100] FIG13 is a schematic diagram of current flow when battery 1 charges battery 2 in the charge-discharge circuit shown in FIG11 .

[0101] FIG14 is a schematic diagram of current flow when the battery 2 charges the inductor in the charge-discharge circuit shown in FIG11 .

[0102] FIG15 is a schematic diagram of current flow when battery 2 charges battery 1 in the charge-discharge circuit shown in FIG11 .

[0103] FIG16 is another circuit diagram of a charging and discharging circuit between two electrical cabinets provided in an embodiment of the present application.

[0104] FIG17 is a schematic diagram of current flow when the battery 1 charges the inductor in the charge-discharge circuit shown in FIG16 .

[0105] FIG18 is a schematic diagram of current flow when battery 1 charges battery 2 in the charge-discharge circuit shown in FIG16 .

[0106] FIG19 is a schematic diagram of current flow when battery 2 charges the inductor in the charge-discharge circuit shown in FIG16 .

[0107] FIG20 is a schematic diagram of current flow when battery 2 charges battery 1 in the charge-discharge circuit shown in FIG16 .

[0108] FIG21 is a flow chart of a method for controlling battery self-heating in a photovoltaic storage system according to an embodiment of the present application.

[0109] FIG22 is a schematic structural diagram of a battery self-heating control device provided in an embodiment of the present application.

[0110] FIG23 is a schematic structural diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0111] The following detailed description of the embodiments of the present application is provided in conjunction with the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present application, but are not intended to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0112] In the description of this application, it should be noted that, unless otherwise specified, "multiple" means more than two; the terms "upper", "lower", "left", "right", "inside", "outside", etc., indicating directions or positional relationships, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly perpendicular, but is within the allowable error range. "Parallel" is not strictly parallel, but is within the allowable error range.

[0113] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of this application. In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0114] Energy storage is paramount in the development and utilization of new energy sources. Related technologies typically convert new energy sources into electrical energy for storage. For example, new energy sources such as solar, wind, hydro, and nuclear energy are converted into electrical energy and stored in batteries in multiple electrical cabinets. However, low temperatures significantly degrade the charge and discharge performance of batteries, significantly impacting the energy conversion of these energy storage systems. Therefore, battery heating is necessary in low-temperature environments.

[0115] The energy storage system of the related art includes a battery and a voltage converter in the electrical cabinet. The battery is connected to the high-voltage bus through the voltage converter, and is connected to the power load or the power grid through the power converter. Among them, the bus capacitor is connected in parallel to the high-voltage bus. Figure 1 shows the circuit structure of the battery Temp in the energy storage system of the related art, where C1 and C2 are bus capacitors. When the temperature of the battery Temp is lower than a certain temperature, the battery Temp needs to be heated. In the related art, the battery Temp, the voltage converter, the power converter and the bus capacitor constitute a charge and discharge circuit. In one stage, the battery Temp charges the bus capacitor, and in the next stage, the bus capacitor charges the battery Temp. These two stages are performed alternately, thereby forming an alternating current flowing through the battery Temp, causing the internal resistance of the battery Temp to heat up, thereby realizing self-heating of the battery Temp.

[0116] However, while researching battery heating solutions for various energy storage systems, the inventors discovered that energy storage systems typically include numerous electrical cabinets connected in parallel to a high-voltage busbar. When the temperatures of batteries in multiple cabinets fall below a certain threshold and require heating, the aforementioned related technology requires sequentially heating the batteries in each cabinet. This sequential heating method, which requires heating all batteries in need of heating, takes a long time and is inefficient.

[0117] Taking a photovoltaic storage system utilizing solar energy as an example, the photovoltaic storage system in related art includes multiple photovoltaic sources, a solar controller corresponding to each photovoltaic source, multiple electrical cabinets, a power converter and a system controller.

[0118] Figure 2 shows a schematic diagram of a solar-to-energy storage system. It illustrates photovoltaic sources (PV1, PV2, ..., PVn) and the solar controllers (MPPT1, MPPT2, ..., MPPTn) connected to each source. The electrical cabinet includes a voltage converter and batteries, which are connected to the batteries. The voltage converter can be a DC-DC converter (DCDC), and the battery can be a battery module or battery pack. Figure 2 schematically illustrates three electrical cabinets, which respectively include DCDC1 and Battery 1, DCDC2 and Battery 2, and DCDC3 and Battery 3.

[0119] The voltage converter, each solar controller, and power converter in each electrical cabinet of the aforementioned solar-to-storage system are all connected in a common line. The power converter can be a DC / AC converter. As shown in Figure 2, the power converter can also be connected to the grid via a grid converter. The system controller can be a LEMS (Local Energy Management System), as shown in Figure 2.

[0120] As shown in FIG2 , in the related art, if the battery temperatures in the three electrical cabinets are all lower than the threshold, if the battery is heated using the charge and discharge circuit between the battery and the bus capacitor shown in FIG1 , the batteries in the three electrical cabinets can only be heated in turn, resulting in very low heating efficiency.

[0121] Based on this, the inventors of this application, through in-depth research, have designed an energy storage system and a battery self-heating control method applicable to the energy storage system. In this energy storage system, a switch module is provided between each electrical cabinet and the high-voltage busbar, and each electrical cabinet is connected in a common line. In the event that a battery temperature in a cabinet is below a threshold, the switch module disconnects the cabinet from the high-voltage busbar, forming a charge-discharge circuit between the cabinets. The battery whose temperature is below the threshold is heated by the charge-discharge circuit between the cabinets.

[0122] The present application forms a charging and discharging circuit between electrical cabinets. Through charging and discharging between electrical cabinets, an alternating current is formed flowing through the batteries in the electrical cabinets, causing the internal resistance of the batteries to heat up. This can simultaneously heat the batteries of multiple electrical cabinets, shortening the time required to heat the batteries of multiple electrical cabinets and improving the heating efficiency of the batteries in the electrical cabinets in the energy storage system.

[0123] The battery self-heating control method provided in the embodiment of the present application can be applied to any energy storage system including multiple electrical cabinets, such as energy storage systems that utilize solar energy, wind energy, nuclear energy, hydropower, geothermal energy, fossil energy and other energy sources. The energy storage system provided in the embodiment of the present application is provided with a switch module between the electrical cabinet and the high-voltage bus. The circuit structure shown in FIG3 is a circuit structure shown in FIG2 in which a switch module is provided between three electrical cabinets and the high-voltage bus. In this way, when it is necessary to heat any battery in the three electrical cabinets, the switch module can be disconnected, and a charge and discharge circuit between the electrical cabinets can be formed in the three electrical cabinets, thereby being able to heat the batteries in multiple electrical cabinets at the same time and improving the battery heating efficiency.

[0124] An embodiment of the present application provides an energy storage system. Referring to FIG4 , the energy storage system includes a system controller 10 , a switch module 20 , and a plurality of electrical cabinets 30 . FIG4 schematically shows two electrical cabinets 30 .

[0125] Multiple electrical cabinets 30 are connected in parallel. One end of the switch module 20 is connected to the high-voltage busbar 40, and the other end is connected to the connection point where the multiple electrical cabinets 30 are connected in parallel. A system controller 10 is in communication with the switch module 20 and each electrical cabinet 30. The system controller 10 is configured to control the formation of a charging and discharging circuit between the multiple electrical cabinets 30 if a cabinet 30 among the multiple electrical cabinets 30 meets preset heating conditions.

[0126] The parallel connection of multiple electric cabinets 30 can be achieved by connecting the multiple electric cabinets 30 to a line, which is then connected to the high-voltage bus. Alternatively, each electric cabinet 30 can be connected to the high-voltage bus via a line.

[0127] FIG4 only shows the circuit connection part, and the communication connection line is not shown. The communication connection between the system controller 10 and the switch module 20 and each electrical cabinet 30 can be a wired connection or a wireless connection. FIG4 only schematically shows the high-voltage bus 40. In actual application, as shown in FIG5 , the energy storage controller and the energy storage can be connected in sequence through the high-voltage bus 40, as well as the power converter and the power grid can be connected in sequence. Among them, the energy storage controller, the power converter and the switch module 20 are connected to the high-voltage bus 40 at one end in a collinear manner. The above-mentioned energy storage can be a photovoltaic source, a wind turbine, etc., and the power converter can be a DCAC.

[0128] The switch module 20 is a switch tube that can be controlled by a signal. Specifically, the switch module 20 can be a bus contactor, an IGBT (Insulated Gate Bipolar Transistor) or a MOS (Field Effect Transistor) tube that can be controlled by a signal.

[0129] The preset heating conditions may include the battery temperature being lower than a preset low-temperature threshold, the battery charge being higher than a preset charge threshold, and the electrical cabinet 30 being free of faults. The preset low-temperature threshold may be -10°C, -20°C, -30°C, etc. The preset charge threshold is the minimum charge level required to support battery charging and discharging.

[0130] When the present application determines that a cabinet 30 that meets the preset heating conditions has appeared, the switch module 20 is disconnected, causing each cabinet 30 to stop transmitting power to the grid and the energy storage to stop storing power in the cabinet 30. A charge-discharge loop is also formed between the multiple cabinets 30, allowing charging and discharging between the cabinets 30, thereby generating an alternating current flowing through the batteries in the multiple cabinets 30. This causes the internal resistance of the batteries in the multiple cabinets 30 to heat simultaneously, achieving simultaneous heating of the batteries in the multiple cabinets 30 and improving heating efficiency.

[0131] As shown in Figure 6 , the electrical cabinet 30 includes batteries 31, a battery management system 32, and a voltage converter 33. The battery management system 32, system controller 10, and voltage converter 33 are all communicatively connected, though this communication connection is not shown in Figure 6 and can be wired or wireless. The batteries 31 are electrically connected to the switch module 20 via the voltage converter 33.

[0132] Each electrical cabinet 30 in the energy storage system has the structure shown in Figure 6 . The voltage converter 33 in each electrical cabinet 30 is electrically connected to the switch module 20 and is in communication with the system controller 10. When a cabinet 30 that meets preset heating conditions appears, the switch module 20 disconnects all cabinets 30 from the high-voltage bus 40, thereby forming a charge-discharge loop between the multiple cabinets 30 and enabling charging and discharging between the cabinets 30.

[0133] The battery management system 32 in each electrical cabinet 30 is used to detect the electrical parameters of the batteries 31 in its respective electrical cabinet 30 and transmit these parameters to the system controller 10. These parameters include the battery 31's temperature, state of charge (SOC), voltage, and current. The system controller 10 receives the electrical parameters uploaded by the battery management system 32 in each electrical cabinet 30 and, based on each parameter, determines whether each electrical cabinet 30 meets the preset heating conditions. If a particular electrical cabinet 30 is determined to meet the preset heating conditions, the system controller 10 controls the switch module 20 to disconnect.

[0134] The battery management system 32 can periodically monitor the electrical parameters of the corresponding battery 31 and upload them to the system controller 10. After receiving the electrical parameters, the system controller 10 compares the temperature of the battery 31, included in the electrical parameters, with a preset low-temperature threshold. If the temperature of the battery 31 is greater than the preset low-temperature threshold, the system controller 10 determines that the battery 31 does not meet the preset heating condition. If the temperature of the battery 31 is less than or equal to the preset low-temperature threshold, the system controller 10 further determines whether the battery 31's charge level is greater than a preset charge threshold. If the battery 31's charge level is less than or equal to the preset charge threshold, the system controller 10 indicates that the battery 31's charge level is too low to support the required charge and discharge, and the system controller 10 determines that the battery 31 does not meet the preset heating condition. If the battery 31's charge level is determined to be greater than the preset charge threshold, the system controller 10 further detects whether the electrical cabinet 30 to which the battery 31 belongs is faulty. This fault may include a fault in the voltage converter 33, a fault in the battery 31, or a fault in the battery management system 32. If a fault is detected in the electrical cabinet 30 to which the battery 31 belongs, the system controller 10 determines that the battery 31 does not meet the preset heating condition. If it is determined that the temperature of the battery 31 is less than or equal to the preset low temperature threshold, the power of the battery 31 is greater than the preset power threshold, and there is no fault in the electrical cabinet 30 to which the battery 31 belongs, it is determined that the battery 31 meets the preset heating conditions.

[0135] When the system controller 10 determines that there are batteries 31 in each electrical cabinet 30 that meet the preset heating conditions, it sends a control instruction for controlling the switch module 20 to disconnect to the switch module 20, and the switch module 20 disconnects under the triggering of the control instruction.

[0136] Based on the electrical parameters of battery 31, the temperature and charge level of battery 31 are determined to determine whether they meet the preset heating conditions. This allows accurate identification of the battery 31 that requires heating and prevents over-discharge caused by charging and discharging when the battery 31 is under-charged. If a battery 31 that meets the preset heating conditions is determined to exist, the switch module 20 is controlled to disconnect, creating conditions for the subsequent formation of a charge-discharge circuit between multiple electrical cabinets 30, enabling charging and discharging between electrical cabinets 30.

[0137] When the system controller 10 determines that a cabinet 30 currently meets the preset heating conditions based on the electrical parameters of the batteries 31 in each cabinet 30, it sends a heating instruction to at least one cabinet 30, including the cabinet 30 that meets the preset heating conditions. Based on the heating instruction, the at least one cabinet 30 establishes a charge-discharge circuit between the cabinets 30, controlling the batteries 31 in the circuit to alternately charge and discharge.

[0138] The above-mentioned heating instruction is used to instruct the electrical cabinet 30 to form a charge-discharge circuit and to perform charge and discharge based on the formed charge-discharge circuit. The heating instruction may include identification information of each electrical cabinet 30 used to form the charge-discharge circuit, stage indication information of each charge and discharge stage, etc. Among them, the identification information of the electrical cabinet 30 may be a device serial number or MAC (Media Access Control Address, physical address) address used to uniquely identify the electrical cabinet 30. The stage indication information is used to indicate the charge and discharge stages included in the charge and discharge circuit, as well as information such as the duration of each stage, the charge and discharge current, etc. The charge and discharge stages included in the charge and discharge circuit may include the battery 31 of the first electrical cabinet 30 charging the battery 31 of the second electrical cabinet 30 in one stage, and the battery 31 of the second electrical cabinet 30 charging the battery 31 of the first electrical cabinet 30 in the next stage. Alternatively, the charging and discharging stages may include a stage in which the battery 31 of the first electrical cabinet 30 first charges the energy storage element in the voltage converter 33 of the first electrical cabinet 30, a next stage in which the battery 31 of the first electrical cabinet 30 and the energy storage element in the voltage converter 33 together charge the battery 31 of the second electrical cabinet 30, a next stage in which the battery 31 of the second electrical cabinet 30 charges the energy storage element in the voltage converter 33 of the second electrical cabinet 30, and a next stage in which the battery 31 of the second electrical cabinet 30 and the energy storage element in the voltage converter 33 together charge the battery 31 of the first electrical cabinet 30.

[0139] When it is determined that there is a battery 31 that meets the preset heating conditions, a heating instruction is sent to the corresponding electric cabinet 30, so that the electric cabinet 30 constructs a charge-discharge circuit including multiple electric cabinets 30 based on the heating instruction, and alternately charges and discharges in the constructed charge-discharge circuit based on the heating instruction, thereby realizing charging and discharging between electric cabinets 30 and electric cabinets 30, and can heat multiple electric cabinets 30 at the same time, thereby improving heating efficiency.

[0140] In some embodiments of the present application, the voltage converter 33 may include at least one bridge arm having a flying capacitor and at least one energy storage element, with the bridge arm and the energy storage element corresponding one to one. One end of the energy storage element is connected to the positive electrode of the battery 31 in the electrical cabinet 30 to which the voltage converter 33 belongs, and the other end of the energy storage element is connected to the connection point between the upper bridge arm and the lower bridge arm in the bridge arm corresponding to the energy storage element. The energy storage element may include at least one element capable of storing electrical energy, such as an inductor and / or a capacitor.

[0141] FIG7 shows a circuit diagram of a voltage converter 33 with a flying capacitor. FIG7 schematically illustrates two bridge arms. In actual applications, the voltage converter 33 may have only one bridge arm, or may have any number of two or more bridge arms. In FIG7 , the bridge arms are connected in parallel, with one end of each bridge arm collinearly connected to the positive terminal of the high-voltage bus 40, and the other end of each bridge arm collinearly connected to the negative terminal of the high-voltage bus 40 and the negative electrode of the battery 31 in the electrical cabinet 30 to which the voltage converter 33 belongs. The energy storage element connected to each bridge arm is connected to the positive electrode of the battery 31 in the electrical cabinet 30 to which the voltage converter 33 belongs. In FIG7 , the energy storage element is represented by an inductor. In FIG7 , each bridge arm schematically illustrates four switching transistors connected in sequence. One end of the flying capacitor is connected between the first two switching transistors, and the other end is connected between the last two switching transistors. That is, the flying capacitor is connected in parallel with the two middle switching transistors of the four switching transistors in the bridge arm.

[0142] The voltage converter 33 may include a flying capacitor, and may include one or more bridge arms, so that the charging and discharging circuits between the electrical cabinets 30 may have a variety of possible circuit structures.

[0143] In other embodiments, the voltage converter 33 includes at least one bridge arm without a flying capacitor and at least two energy storage elements, with each bridge arm connected to the two energy storage elements. Each bridge arm includes at least four switching transistors connected in sequence; the positive and negative electrodes of the battery 31 in the electrical cabinet 30 to which the voltage converter 33 belongs are respectively connected to the two energy storage elements connected to the bridge arm.

[0144] FIG8 shows a circuit diagram of a voltage converter 33 without a flying capacitor. FIG8 schematically illustrates two bridge arms. In actual applications, the voltage converter 33 may have only one bridge arm, or may have any number of two or more bridge arms. In FIG8 , the bridge arms are connected in parallel, with one end of each bridge arm collinearly connected to the positive terminal of the high-voltage bus 40, and the other end of each bridge arm collinearly connected to the negative terminal of the high-voltage bus 40. FIG8 schematically illustrates only four switching tubes connected in sequence in the bridge arms. One bridge arm is connected to two energy storage elements, and the energy storage elements in FIG8 are illustrated as inductors. One end of one of the inductors is connected to the connection point of the first two switching tubes in the bridge arm, and the other end of the inductor is connected to the positive terminal of the battery 31 in the electrical cabinet 30 to which the voltage converter 33 belongs. One end of the other inductor is connected to the connection point of the last two switching tubes in the bridge arm, and the other end of the other inductor is connected to the negative terminal of the battery 31 in the electrical cabinet 30 to which the voltage converter 33 belongs.

[0145] In this embodiment, the voltage converter 33 may not have a flying capacitor, and may include one or more bridge arms, so that the charging and discharging circuits between the electrical cabinets 30 may have various possible circuit structures.

[0146] In the above-mentioned voltage converter 33 with or without a flying capacitor, a switch module 20 is connected between each bridge arm and the positive terminal of the high-voltage bus 40. When it is necessary to heat the battery 31 in the electrical cabinet 30, the switch module 20 is first disconnected, thereby disconnecting the circuit between the voltage converter 33 and the battery 31 in the electrical cabinet 30 and the high-voltage bus 40, creating conditions for the subsequent construction of a charging and discharging circuit between the electrical cabinets 30.

[0147] In an embodiment of the present application, a switch module is provided between each electric cabinet and the high-voltage bus in the energy storage system, and the system controller is in communication with the voltage converter and the battery management system in each electric cabinet. When it is determined based on the electrical parameters of the batteries in each electric cabinet that an electric cabinet that meets the preset heating conditions appears, the switch module is disconnected, so that each electric cabinet stops transmitting electricity to the power grid, and the energy storage energy also stops storing electricity in the electric cabinet. A charge-discharge loop is formed between multiple electric cabinets, so that charging and discharging are carried out between the electric cabinets, thereby forming an alternating current flowing through the batteries in multiple electric cabinets, causing the internal resistance of the batteries in multiple electric cabinets to heat up at the same time, thereby achieving simultaneous heating of the batteries in multiple electric cabinets and improving heating efficiency.

[0148] The present application provides a method for controlling battery self-heating, which is applied to the energy storage systems provided in the above embodiments. Referring to the flowchart of the battery self-heating control method shown in FIG9 , the method specifically includes the following steps:

[0149] Step 101: Determine whether there is at least one target electrical cabinet that meets a preset heating condition.

[0150] The preset heating conditions may include the battery temperature being below a preset low-temperature threshold, the battery charge being above a preset charge threshold, and the presence of no faults in the electrical cabinet to which the battery belongs. The preset low-temperature threshold may be -10°C, -20°C, -30°C, etc. The preset charge threshold is the minimum charge required to support battery charging and discharging. The switch module is a signal-controlled switch tube, specifically a bus contactor, a signal-controlled IGBT, or a MOS tube.

[0151] Step 102: Control multiple electrical cabinets including the target electrical cabinet to form a charge-discharge loop, and charge and discharge the batteries in the target electrical cabinet based on the charge-discharge loop.

[0152] When the present application determines that an electrical cabinet that meets the preset heating conditions has appeared, the switch module is disconnected, causing each electrical cabinet to stop transmitting power to the power grid and the energy storage to stop storing power in the electrical cabinet, creating conditions for the subsequent construction of a charging and discharging circuit between the electrical cabinets. A charging and discharging circuit is formed between multiple electrical cabinets, allowing charging and discharging between electrical cabinets, thereby forming an alternating current flowing through the batteries in multiple electrical cabinets, causing the internal resistance of the batteries in multiple electrical cabinets to heat up simultaneously, thereby achieving simultaneous heating of the batteries in multiple electrical cabinets and improving heating efficiency.

[0153] The circuit structure of the battery self-heating control method provided in the embodiment of the present application is based on the structure of the energy storage system shown in Figure 4. In this energy storage system, each electrical cabinet includes a battery, a battery management system, and a voltage converter. The battery management system is respectively connected to the voltage converter and the system controller, and the voltage converter is also connected to the system controller. The battery management system is used to detect the electrical parameters of the battery, which include information such as the battery temperature, state of charge (SOC), voltage or current.

[0154] During the operation of the energy storage system, the battery management system in each electrical cabinet periodically detects the electrical parameters of the batteries in the cabinet and sends the detected electrical parameters to the system controller. The battery management system can detect and upload electrical parameters at a period of 1 minute, 5 minutes, 10 minutes, 30 minutes, 1 hour, or 2 hours, etc. This embodiment of the application does not limit the specific value of this period, and it can be set according to actual needs in actual applications.

[0155] After obtaining the electrical parameters of the batteries in each electrical cabinet, the system controller determines whether there is a target electrical cabinet that currently meets the preset heating conditions based on the electrical parameters of the batteries in each electrical cabinet. Specifically, for each electrical cabinet, the system controller parses the battery temperature and state of charge (SOC) from the electrical parameters corresponding to the electrical cabinet, determines whether the battery temperature is below a preset low-temperature threshold, and if so, further determines whether the battery SOC is greater than a preset charge threshold. If it is determined that the battery temperature is below the preset low-temperature threshold and the SOC is greater than the preset charge threshold, the system controller further detects whether the electrical cabinet to which the battery belongs is faulty. If it is determined that the electrical cabinet to which the battery belongs is not faulty, the electrical cabinet is determined to be a target electrical cabinet that meets the preset heating conditions. If it is determined that the battery temperature is higher than the preset low-temperature threshold, or if it is determined that the battery temperature is lower than the preset low-temperature threshold but the battery SOC is less than or equal to the preset charge threshold, or if a fault is detected in the electrical cabinet to which the battery belongs, the system controller determines that the electrical cabinet does not meet the preset heating conditions.

[0156] By judging whether the battery meets the preset heating conditions based on the battery's electrical parameters, it can accurately identify batteries that are too cold and need to be heated. It can also avoid battery over-discharge caused by charging and discharging when the battery is insufficiently charged, and it can also avoid the situation where the charging and discharging process cannot be successfully completed due to a fault in the electrical cabinet.

[0157] When the system controller determines that a target panel meeting the preset heating conditions exists, it sends a control instruction to the switch module, triggering it to disconnect. Once the switch module is disconnected, the subsequent charging and discharging currents from the panel will not flow to the high-voltage busbar, but instead to the other panels forming the charging and discharging loop, creating a structural condition for inter-panel charging and discharging.

[0158] Simultaneously with or after the system controller controls the switch module to disconnect, it controls multiple cabinets, including the target cabinet, to form a charge-discharge circuit. Specifically, the system controller determines multiple candidate cabinets for forming the charge-discharge circuit, including the target cabinet. The system controller controls the power devices in the voltage converters of the multiple candidate cabinets to switch on and off, forming alternating charging and discharging circuits.

[0159] The system controller determines the electrical cabinets that form the charge-discharge loop and controls the on-off switching of the power devices in the voltage converters of these electrical cabinets, thereby forming a charge-discharge loop between these electrical cabinets and realizing charging and discharging between these electrical cabinets. This can cause the internal resistance of the batteries in these electrical cabinets to heat up simultaneously, thereby improving the efficiency of heating the batteries in multiple electrical cabinets in the energy storage system.

[0160] Regarding the step of determining multiple candidate electrical cabinets for forming a charge-discharge loop, in some embodiments, if the system controller determines that there are multiple target electrical cabinets that meet the preset heating conditions, these multiple target electrical cabinets can be directly determined as multiple candidate electrical cabinets for forming a charge-discharge loop. In other words, a charge-discharge loop is formed between the multiple target electrical cabinets that require heating.

[0161] In other embodiments, if there is only one target electrical cabinet meeting the preset heating conditions, at least one electrical cabinet is selected from the electrical cabinets meeting the preset charging and discharging conditions to form a charging and discharging circuit between the selected at least one electrical cabinet and the target electrical cabinet. The preset charging and discharging conditions include a battery temperature greater than a preset low-temperature threshold and a battery charge greater than a preset charge threshold, meaning the battery charge can support the required charge and discharge.

[0162] If there are multiple target electrical cabinets that meet the preset heating conditions, at least one electrical cabinet can be selected from the electrical cabinets that meet the preset charging and discharging conditions, and at least one charging and discharging circuit can be formed between the at least one selected electrical cabinet and the multiple target electrical cabinets. Because the charging and discharging performance of batteries in target electrical cabinets whose battery temperatures are below the preset low-temperature threshold is affected by low temperatures, while the charging and discharging performance of batteries in electrical cabinets whose temperatures are above the preset low-temperature threshold is normal, forming a charging and discharging circuit using the electrical cabinets that meet the preset charging and discharging conditions and the target electrical cabinets that need to be heated helps improve the efficiency of charging and discharging based on this charging and discharging circuit, further improving the heating efficiency of the batteries in the multiple electrical cabinets.

[0163] If a cabinet meeting the preset charge / discharge conditions is needed to form a charge / discharge loop with the target cabinet, the system controller first identifies a cabinet meeting the preset charge / discharge conditions based on the electrical parameters of the batteries in the remaining cabinets, excluding the target cabinet. Specifically, it identifies cabinets whose battery temperatures exceed a preset low-temperature threshold and whose battery capacities exceed a preset charge threshold. The system controller then selects at least one cabinet from the cabinets meeting the preset charge / discharge conditions. The target cabinet and the at least one selected cabinet are then identified as candidate cabinets for forming the charge / discharge loop.

[0164] The number of the at least one selected electric cabinet may be equal to or different from the number of electric cabinets that meet the preset heating conditions.

[0165] Among them, the method of selecting at least one electric cabinet from the electric cabinets that meet the preset charging and discharging conditions can be to randomly select at least one electric cabinet, or to select at least one electric cabinet with the lowest battery temperature or the largest battery power from the electric cabinets that meet the preset charging and discharging conditions.

[0166] Randomly selecting at least one electrical cabinet from among the electrical cabinets that meet the preset charge and discharge conditions reduces the computational effort of the system controller and allows for rapid selection of the required electrical cabinet. Selecting at least one electrical cabinet with the lowest battery temperature from among the electrical cabinets that meet the preset charge and discharge conditions facilitates heating the batteries in these cabinets with lower battery temperatures after the charge and discharge circuit is subsequently established, raising the battery temperature and improving the charge and discharge performance of the batteries in these cabinets. Selecting at least one electrical cabinet with the highest battery capacity from among the electrical cabinets that meet the preset charge and discharge conditions prevents over-discharge of batteries during the charge and discharge process in the subsequently established charge and discharge circuit. Because the battery temperatures of the electrical cabinets that meet the preset charge and discharge conditions are all above the preset low-temperature threshold, forming a charge and discharge circuit using the electrical cabinets that meet the preset charge and discharge conditions and the target electrical cabinets that require heating helps improve the efficiency of inter-cabinet charging and discharging, further enhancing the heating efficiency of the batteries in multiple electrical cabinets.

[0167] After determining multiple candidate cabinets for forming the charge-discharge circuits, the system controller also determines, based on these candidate cabinets, the candidate cabinets for each of at least one of the charge-discharge circuits to be formed. Each charge-discharge circuit includes at least one target cabinet that meets preset heating conditions. In other words, the system controller needs to determine the number of charge-discharge circuits to be constructed and the cabinets that comprise each circuit. The system controller then controls the power devices of the voltage converters in the candidate cabinets included in each charge-discharge circuit to switch between them, forming alternating charging and discharging circuits within each circuit.

[0168] The system controller determines the electrical cabinets included in each charging and discharging circuit to be constructed, and controls the on and off of the power devices of the voltage converters in the electrical cabinets included in each charging and discharging circuit, thereby realizing charging and discharging between the electrical cabinets in each charging and discharging circuit, and heating the batteries of multiple electrical cabinets at the same time.

[0169] In some embodiments, the system controller may determine that only one charge-discharge loop is formed, divide the multiple candidate cabinets into a first cabinet group and a second cabinet group, and determine the first cabinet group and the second cabinet group as two groups of cabinets in one charge-discharge loop. That is, only one charge-discharge loop is formed, in which batteries in the first cabinet group and batteries in the second cabinet group charge and discharge each other.

[0170] If the number of candidate cabinets determined is an even number, the number of cabinets included in the first and second cabinet groups can be equal. If the number of candidate cabinets determined is an odd number, the number of cabinets included in the first and second cabinet groups can be unequal. One cabinet group can be divided into two groups with one more cabinet than the other. This minimizes the difference in the number of cabinets between the first and second cabinet groups, allowing for more balanced charging and discharging between the two cabinet groups.

[0171] In other embodiments, the system controller may also determine to constitute multiple charging and discharging circuits, where the number of the multiple charging and discharging circuits is less than or equal to the number of target electrical cabinets; divide the multiple candidate electrical cabinets into multiple groups of electrical cabinets, each group of electrical cabinets including at least two candidate electrical cabinets; and determine the multiple groups of electrical cabinets as candidate electrical cabinets included in each of the multiple charging and discharging circuits.

[0172] When the number of multiple charge-discharge circuits is equal to the number of target cabinets, each charge-discharge circuit can include one target cabinet. When the number of multiple charge-discharge circuits is less than the number of target cabinets, one charge-discharge circuit can include multiple target cabinets. For each charge-discharge circuit, the number of cabinets included in the charge-discharge circuit can be an even number or an odd number. When an even number of cabinets is included, the cabinets included in the charge-discharge circuit can be divided into two groups, and then charge and discharge can be performed between the two groups. When an odd number of cabinets is included, the cabinets included in the charge-discharge circuit can be divided into two groups, one of which has one more cabinet than the other, and then charge and discharge can be performed between the two groups.

[0173] As an example, every two cabinets from the multiple candidate cabinets identified can form a charge-discharge circuit. If the number of candidate cabinets identified is an odd number, every two cabinets can be controlled to form a charge-discharge circuit in a time-sharing manner. For example, assuming three candidate cabinets are identified, namely, cabinets 1, 2, and 3, cabinets 1 and 2 can be controlled to form a charge-discharge circuit first. After a period of time, cabinets 2 and 3 can be controlled to form a charge-discharge circuit. After a period of time, cabinets 2 and 3 can be controlled to form a charge-discharge circuit again. This cycle can be repeated so that two cabinets from among cabinets 1, 2, and 3 are heated simultaneously at the same time.

[0174] Whether multiple candidate electrical cabinets constitute one charge-discharge loop or multiple charge-discharge loops can be determined by pre-configuring a charge-discharge loop construction strategy in the system controller, and the system controller makes the determination based on the construction strategy.

[0175] The system controller can flexibly determine the electrical cabinets included in the charge and discharge circuits to be constructed, and then control the various charge and discharge circuits to alternately form charging circuits and discharging circuits based on the determined electrical cabinets included in each charge and discharge circuit, thereby achieving simultaneous heating of the batteries in the electrical cabinets included in each charge and discharge circuit, thereby improving heating efficiency.

[0176] After determining the number of charge-discharge circuits to be constructed and the electrical cabinets included in each charge-discharge circuit, the system controller generates heating instructions corresponding to each charge-discharge circuit and sends the heating instructions to the electrical cabinets in the corresponding charge-discharge circuit. Because the system controller generates heating instructions and controls the charging and discharging of the charge-discharge circuit based on the heating instructions in the same manner for each charge-discharge circuit, the present embodiment is described in detail using the first charge-discharge circuit as any of the charge-discharge circuits.

[0177] For the first charge-discharge loop, the system controller first generates a heating instruction corresponding to the first charge-discharge loop based on the electrical cabinets included in the first charge-discharge loop. The heating instruction instructs the electrical cabinets included in the first charge-discharge loop to form the first charge-discharge loop and perform charging and discharging. The heating instruction may include identification information of each electrical cabinet used to form the first charge-discharge loop and stage indication information for each charge and discharge stage.

[0178] The system controller sends the heating instruction to the voltage converter of the electric cabinet in the first charge-discharge circuit. Based on the heating instruction, the system controller controls the first charge-discharge circuit to form an alternating charging circuit and a discharging circuit.

[0179] The system controller sends a heating instruction to the voltage converters of the electrical cabinets in the first charge and discharge circuit, so that these voltage converters can control the on and off of their own power devices based on the heating instruction, thereby forming an alternating charging circuit and discharging circuit in the first charge and discharge circuit, thereby achieving simultaneous heating of the batteries of each electrical cabinet in the first charge and discharge circuit, improving the heating efficiency, and increasing the temperature of the battery with too low a temperature and the charge and discharge performance of the battery.

[0180] In some embodiments, the system controller can send a heating instruction to the voltage converter of each electrical cabinet in the first charge and discharge loop, so that the voltage converter of each electrical cabinet directly obtains the heating instruction, constructs the first charge and discharge loop according to the heating instruction, and controls the charging and discharging of each battery based on the heating instruction.

[0181] In other embodiments, the system controller may also send the heating instruction only to the voltage converter of the target panel in the first charge-discharge loop. Because all panels in the energy storage system are connected in parallel, the heating instruction can be forwarded by the voltage converter of the target panel to the voltage converters of other panels in the first charge-discharge loop. This provides another implementation for sending heating instructions, saving data traffic for the system controller.

[0182] When determining the electrical cabinets included in the first charge-discharge circuit, the system controller also determines a division method among the electrical cabinets included in the first charge-discharge circuit, dividing the included electrical cabinets into two groups, referred to in this embodiment as a first electrical cabinet subset and a second electrical cabinet subset, each of which includes at least one electrical cabinet. The system controller also determines the relationship between the battery power levels corresponding to each electrical cabinet in the first electrical cabinet subset and the battery power levels corresponding to each electrical cabinet in the second electrical cabinet subset. The battery power level corresponding to each electrical cabinet may be the sum of the power levels of the batteries in each electrical cabinet.

[0183] If the battery levels of the first and second cabinet subsets are unequal, the cabinet subset with the higher battery level can directly charge the cabinet subset with the lower battery level. However, if the battery levels of the first and second cabinet subsets are equal, neither the first nor the second cabinet subset can directly charge the other. Therefore, the batteries of each cabinet in one cabinet must first charge the energy storage elements of the voltage converter in their respective cabinets. Only then can the batteries of that cabinet and the voltage converter's energy storage elements be used together to charge the batteries of the other cabinet subset.

[0184] When determining the electrical cabinets included in each charge and discharge loop, the system controller can determine the electrical cabinets included in the charge and discharge loop based on the power level of the batteries in each candidate electrical cabinet, and try to make the battery power levels corresponding to the first electrical cabinet subset and the second electrical cabinet subset divided in the charge and discharge loop unequal. This can eliminate the need to first charge the energy storage element in the voltage converter with the battery, simplify the subsequent charge and discharge process of the charge and discharge circuit, and improve efficiency.

[0185] In some embodiments, if the battery power corresponding to the first subset of electrical cabinets is greater than the battery power corresponding to the second subset of electrical cabinets, the heating instruction sent by the system controller to the electrical cabinets in the first charging and discharging circuit may include two-stage stage indication information, one stage indication information is used to instruct the batteries of the first subset of electrical cabinets to charge the batteries of the second subset of electrical cabinets, and the other stage indication information is used to instruct the batteries of the second subset of electrical cabinets to charge the batteries of the first subset of electrical cabinets.

[0186] Specifically, after the voltage converters of each cabinet in the first charge-discharge circuit receive the heating instruction, in a first phase, the voltage converters of each cabinet in the first cabinet set, based on the heating instruction, all perform the same first power device on-off operation. Simultaneously, the voltage converters of each cabinet in the second cabinet set, based on the heating instruction, all perform the same second power device on-off operation. Thus, in the first phase, a circuit is formed in which the batteries in each cabinet in the first cabinet set charge the batteries in each cabinet in the second cabinet set. In a second phase, the voltage converters of each cabinet in the second cabinet set, based on the heating instruction, all perform the same first power device on-off operation. Simultaneously, the voltage converters of each cabinet in the first cabinet set, based on the heating instruction, all perform the same second power device on-off operation. Thus, in the second phase, a circuit is formed in which the batteries in each cabinet in the second cabinet set charge the batteries in each cabinet in the first cabinet set. That is, in the second phase, a circuit is formed in which the batteries in each cabinet in the first cabinet set discharge the batteries in each cabinet in the second cabinet set.

[0187] By cyclically executing the first and second stages, alternating charging and discharging circuits are formed in the first charge-discharge circuit. By controlling the on and off of the power devices in the voltage converter, the batteries in the first electrical cabinet subset and the batteries in the second electrical cabinet subset alternately charge each other, achieving self-heating of the batteries in each electrical cabinet in the first charge-discharge circuit and improving the battery heating efficiency.

[0188] In other embodiments, if the battery power corresponding to the first subset of electrical cabinets is equal to the battery power corresponding to the second subset of electrical cabinets, the heating instructions sent by the system controller to the electrical cabinets in the first charge-discharge circuit may include four stages of stage indication information, wherein the first stage indication information is used to instruct the batteries of the first subset of electrical cabinets to charge the energy storage elements of the voltage converter of the electrical cabinet to which the batteries belong. The second stage indication information is used to instruct the batteries of the first subset of electrical cabinets and the aforementioned energy storage elements to charge the batteries of the second subset of electrical cabinets together. The third stage indication information is used to instruct the batteries of the second subset of electrical cabinets to charge the energy storage elements of the voltage converter of the electrical cabinet to which the batteries belong. The fourth stage indication information is used to instruct the batteries of the second subset of electrical cabinets and the energy storage elements to charge the batteries of the first subset of electrical cabinets together.

[0189] Specifically, after the voltage converters of each cabinet in the first charge-discharge circuit receive the heating instruction, in a first phase, the voltage converters of each cabinet in the first cabinet set, based on the heating instruction, all perform the same third on-off operation of the power device. Simultaneously, the power devices of the voltage converters of each cabinet in the second cabinet set are all disconnected. Thus, in the first phase, a circuit is formed in which the batteries of each cabinet in the first cabinet set charge the energy storage elements of the voltage converters in their respective cabinets. In the second phase, the voltage converters of each cabinet in the first cabinet set all perform the same fourth on-off operation of the power device. Simultaneously, the power devices of the voltage converters of each cabinet in the second cabinet set all perform the same fifth on-off operation of the power device. Thus, in the second phase, a circuit is formed in which the batteries of each cabinet in the first cabinet set and the energy storage elements of the voltage converters charge the batteries of each cabinet in the second cabinet set.

[0190] Similarly, in the third stage, the voltage converters in each cabinet in the second cabinet set, based on the heating instruction, all perform the same fifth power device on-off operation, while the power devices of the voltage converters in each cabinet in the first cabinet set are all disconnected. This control, in the third stage, forms a circuit in which the batteries in each cabinet in the second cabinet set charge the energy storage elements of the voltage converters in their respective cabinets. In the fourth stage, the voltage converters in each cabinet in the second cabinet set all perform the same sixth power device on-off operation, while the power devices of the voltage converters in each cabinet in the first cabinet set all perform the same seventh power device on-off operation. This control, in the fourth stage, forms a circuit in which the batteries in each cabinet in the second cabinet set and the energy storage elements of the voltage converters charge the batteries in each cabinet in the first cabinet set.

[0191] By cyclically executing the above four stages from the first to the fourth, an alternating charging circuit and discharging circuit are formed in the first charging and discharging circuit. By controlling the on and off of the power devices in the voltage converter, self-heating of the batteries in each electrical cabinet in the first charging and discharging circuit is achieved, thereby improving the battery heating efficiency.

[0192] In some embodiments of the present application, when the number of batteries included in the first electrical cabinet subset is greater than the number of batteries included in the second electrical cabinet subset, the duration of charging from the first electrical cabinet subset to the second electrical cabinet subset is controlled to be shorter than the duration of charging from the second electrical cabinet subset to the first electrical cabinet subset based on the heating instruction. This prevents overcharging of the batteries in the second electrical cabinet subset during the charging and discharging process.

[0193] Each of the other charge-discharge circuits identified by the system controller is controlled to charge and discharge in the same manner as the first charge-discharge circuit. This allows the batteries of a greater number of electrical cabinets to be heated simultaneously, greatly improving heating efficiency.

[0194] While controlling the charging and discharging of each charging and discharging circuit in the above manner, a determination is made as to whether a preset heating stop condition has been met based on the electrical parameters of the batteries in each electrical cabinet included in the charging and discharging circuit. If the preset heating stop condition is determined to have been met, a heating stop instruction is sent to the voltage converter of the electrical cabinet in the charging and discharging circuit.

[0195] The preset heating stop conditions include the presence of a battery in the charge / discharge circuit whose temperature meets a preset abnormal condition, or the battery temperature of a target electrical cabinet in the charge / discharge circuit that requires heating reaching a preset required temperature. These abnormal conditions may include a battery temperature exceeding a preset temperature threshold, or a battery temperature rise rate exceeding a preset rate. The preset required temperature may be 10°C, 15°C, 20°C, etc.

[0196] Specifically, the battery management system in each electrical cabinet within each charging and discharging circuit monitors the temperature of the batteries in that cabinet in real time and determines whether the battery temperature meets a preset abnormality condition. When the battery management system detects that the battery temperature meets the preset abnormality condition, it sends a temperature abnormality message to the system controller. Upon receiving this temperature abnormality message, the system controller determines that the preset heating stop condition has been met.

[0197] If the battery management system determines that the battery temperature does not meet the preset abnormal condition, the battery management system also determines whether the battery temperature is greater than or equal to the preset required temperature. If so, the battery management system determines that the preset heating stop condition has been met and sends a temperature compliance message to the system controller. Upon receiving the temperature compliance message, the system controller determines that the preset heating stop condition has been met.

[0198] In some implementations, the battery management system may also directly transmit the detected battery temperature to the system controller, which then determines whether the battery temperature meets a preset abnormality condition and whether the battery temperature is greater than or equal to a preset required temperature. When it is determined that the battery temperature meets the preset abnormality condition or that the battery temperature is greater than or equal to the preset required temperature, it is determined that the preset heating stop condition has been met.

[0199] When the system controller determines that the battery in a particular electrical cabinet meets the preset heating stop condition, it sends a heating stop command to the voltage converters of each electrical cabinet in the charge-discharge circuit to which that electrical cabinet belongs. Upon receiving the heating stop command, each voltage converter restores the on / off state of its power device to its initial state, no longer forming a charge-discharge circuit, and stops charging and discharging. The initial state of the voltage converter's power device can be the on / off state of the power device before forming the charge-discharge circuit.

[0200] In other implementations, the battery management system may first determine whether the battery temperature meets a preset stop heating condition. If it determines that the preset stop heating condition is met, the battery management system sends the determination result to the voltage converter in the electrical cabinet to which the battery management system belongs. After receiving the determination result, the voltage converter determines that the preset stop heating instruction is currently met and controls the on / off state of its own power device to return to the initial state. At the same time, the voltage converter also sends a stop heating instruction to the voltage converters of other electrical cabinets in the charge and discharge circuit where the voltage converter is located, and sends instruction information for instructing to stop heating to the system controller. After receiving the stop heating instruction, the voltage converters of the other electrical cabinets also control the on / off state of their respective power devices to return to the initial state.

[0201] Because the communication distance between the battery management system and the voltage converter in the same electrical cabinet is shorter, the battery management system directly transmits the battery temperature judgment result to the voltage converter in the same electrical cabinet, which can stop charging and discharging more quickly when the battery meets the preset heating stop conditions, effectively reducing the safety hazards caused by abnormal battery temperature, and also effectively reducing the situation where the battery temperature continues to rise after reaching the preset required temperature, resulting in overtemperature.

[0202] During the charging and discharging process based on the charging and discharging circuit, the system controller can also detect in real time whether there is a fault in each electrical cabinet in the charging and discharging circuit. If a fault is detected in a certain electrical cabinet, a stop heating instruction is sent to the voltage converters of each electrical cabinet in the charging and discharging circuit to which the faulty electrical cabinet belongs. After receiving the stop heating instruction, each voltage converter controls the on and off state of its own power device to return to the initial state.

[0203] During the charging and discharging process, the charging and discharging circuits formed between the electrical cabinets determine in real time whether the preset heating stop conditions have been met based on the electrical parameters of the batteries in the cabinets. When this condition is determined to have been met, the charging and discharging circuits are promptly controlled to stop charging and discharging. This prevents safety issues caused by continued charging and discharging when the battery temperature is abnormal, and also prevents excessive battery temperatures from being caused by continued charging and discharging after the battery has reached the preset required temperature.

[0204] In an embodiment of the present application, when it is determined that an electrical cabinet meets the preset heating conditions, the switch modules between each electrical cabinet and the high-voltage busbar are controlled to disconnect, allowing the current discharged from the batteries of the subsequent electrical cabinet to flow to the batteries of other electrical cabinets, creating structural conditions for forming a charging and discharging circuit between electrical cabinets. A charging and discharging circuit is formed between multiple electrical cabinets, allowing charging and discharging between electrical cabinets, forming an alternating current flowing through the batteries in multiple electrical cabinets, causing the internal resistance of the batteries in multiple electrical cabinets to heat simultaneously, thereby achieving simultaneous heating of the batteries in multiple electrical cabinets and improving heating efficiency.

[0205] To facilitate understanding of the battery self-heating control method proposed in the embodiment of the present application, the following is an explanation with reference to a specific example. This example takes a photovoltaic storage system as an example. FIG10 shows a circuit structure diagram of the photovoltaic storage system. The photovoltaic storage system includes an electrical cabinet 1 and an electrical cabinet 2. The electrical cabinet 1 includes a battery 1, a battery management system 1, and a DCDC power module 1. The electrical cabinet 2 includes a battery 2, a battery management system 2, and a DCDC power module 2. The system controller of the photovoltaic storage system is a LEMS. The battery self-heating control method based on the photovoltaic storage system specifically includes the following steps:

[0206] A1: Battery management system 1 collects first electrical parameters of battery 1, such as temperature, SOC, voltage and current, and transmits the first electrical parameters to LEMS; battery management system 2 collects second electrical parameters of battery 2, and transmits the second electrical parameters to LEMS.

[0207] A2: The LEMS determines whether the temperature of battery 1 or battery 2 is lower than a preset low temperature threshold T1 based on the first electrical parameter and the second electrical parameter. If yes, step A3 is executed; if not, the process returns to step A1.

[0208] A3: LEMS determines whether the power level of battery 1 or battery 2 is lower than a preset power threshold based on the first electrical parameter and the second electrical parameter. If not, execute step A4; if yes, return to step A1.

[0209] A4: LEMS detects whether there is a fault in electrical cabinet 1 and electrical cabinet 2. If not, execute step A5; if yes, return to step A1.

[0210] A5: The LEMS control switch module is disconnected, and the LEMS sends a heating instruction to the DCDC power module 1 and the DCDC power module 2.

[0211] After the control switch module is disconnected, the system enters the cabinet heating mode for inter-cabinet charging and discharging. DCDC power modules 1 and 2 can use topologies with or without flying capacitors, and the bridge arms can adopt single-arm or multi-arm structures. The following examples illustrate DCDC power modules 1 and 2 using a three-arm structure with or without flying capacitors.

[0212] Example 1:

[0213] As shown in Figure 11, DCDC power module 1 and DCDC power module 2 adopt a three-bridge arm structure with a flying capacitor. The first bridge arm of DCDC power module 1 is connected to the four switching tubes VA1, VA2, VA3 and VA4 in sequence. The flying capacitor C fly1 The second bridge arm of the DCDC power module 1 is connected in parallel with the series-connected VA2 and VA3. The second bridge arm of the DCDC power module 1 is connected in sequence to the four switching tubes VA5, VA6, VA7 and VA8, and the flying capacitor C fly2 The third bridge arm of the DCDC power module 1 is connected in parallel with the series-connected VA6 and VA7. The third bridge arm of the DCDC power module 1 is connected in sequence to the four switching tubes VA9, VA10, VA11 and VA12. The flying capacitor C fly3 The switches VA10 and VA11 are connected in parallel. The connection point between switches VA2 and VA3 is connected to one end of inductor LA1. The connection point between switches VA6 and VA7 is connected to one end of inductor LA2. The connection point between switches VA10 and VA11 is connected to one end of inductor LA3. The other ends of inductors LA1, LA2, and LA3 are all connected to the positive terminal of battery 1.

[0214] As shown in FIG11 , the first bridge arm of the DCDC power module 2 is connected to the four switch tubes VB1, VB2, VB3 and VB4 in sequence, and the flying capacitor C fly4 The second bridge arm of DCDC power module 2 is connected in parallel with VB2 and VB3 in series. The second bridge arm of DCDC power module 2 is connected in sequence to the four switching tubes VB5, VB6, VB7 and VB8, and the flying capacitor C fly5 The third bridge arm of the DCDC power module 2 is connected in parallel with the series-connected VB6 and VB7. The third bridge arm of the DCDC power module 2 is connected in sequence to the four switching tubes VB9, VB10, VB11 and VB12, and the flying capacitor C fly6The switches VB10 and VB11 are connected in parallel. The connection point between switches VB2 and VB3 is connected to one end of inductor LB1. The connection point between switches VB6 and VB7 is connected to one end of inductor LB2. The connection point between switches VB10 and VB11 is connected to one end of inductor LB3. The other ends of inductors LB1, LB2, and LB3 are all connected to the positive electrode of battery 2.

[0215] The first bridge arm of the DCDC power module 1 is close to one end of VA1, the second bridge arm is close to one end of VA5, and the third bridge arm is close to one end of VA9, and the first bridge arm of the DCDC power module 2 is close to one end of VB1, the second bridge arm is close to one end of VB5, and the third bridge arm is close to one end of VB9 are connected in a collinear manner.

[0216] The first bridge arm of DCDC power module 1 is close to one end of VA4, the second bridge arm is close to one end of VA8, and the third bridge arm is close to one end of VA12; the first bridge arm of DCDC power module 2 is close to one end of VB4, the second bridge arm is close to one end of VB8, and the third bridge arm is close to one end of VB12, as well as the negative poles of batteries 1 and 2 are connected in a collinear manner.

[0217] As shown in FIG11 , capacitor CA2 is connected in parallel to both ends of battery 1, capacitor CB2 is connected in parallel to both ends of battery 2, capacitor CA1 is connected in parallel to the three bridge arms of DCDC power module 1, and capacitor CB1 is connected in parallel to the three bridge arms of DCDC power module 2.

[0218] Based on the circuit structure shown in FIG11 , the above-mentioned step A5 is followed by the following step B1 .

[0219] B1: The switch tubes VA3, VA4, VA7, VA8, VA11, and VA12 in the DCDC power module 1 are turned on, and VA1, VA2, VA5, VA6, VA9, and VA10 are turned off; all the switch tubes in the DCDC power module 2 are disconnected.

[0220] At this time, battery 1 is discharging, while inductors LA1, LA2, and LA3 in DCDC power module 1 are charging. The battery 1 discharge circuit is: Battery 1 positive electrode → LA1, VA3, VA4 / LA2, VA7, VA8 / LA3, VA11, VA12 → Battery 1 negative electrode. The current flow is shown in Figure 12.

[0221] After battery 1 charges inductors LA1, LA2, and LA3 for a certain period of time, step B2 is performed. The duration of battery 1 charging inductors LA1, LA2, and LA3 can be included in the heating instruction sent by the system controller. DCDC power module 1 and DCDC power module 2 control the duration of each stage based on the heating instruction.

[0222] B2: In DCDC power module 1, the switch tubes VA1, VA2, VA5, VA6, VA9, and VA10 are turned on, and VA3, VA4, VA7, VA8, VA11, and VA12 are turned off; in DCDC power module 2, VB1, VB2, VB5, VB6, VB9, and VB10 are turned on, and VB3, VB4, VB7, VB8, VB11, and VB12 are turned off.

[0223] At this time, battery 1 is discharged and battery 2 is charged. The current loop is: battery 1 positive electrode → LA1, VA1, VA2 / LA2, VA5, VA6 / LA3, VA9, VA10 → VB1, VB2, LB1 / VB5, VB6, LB2 / VB9, VB10, LB3 → battery 2 positive electrode → battery 2 negative electrode → battery 1 negative electrode. The current flow is shown in Figure 13.

[0224] Step B2 is executed for a certain time and then step B3 is executed. The heating instruction may include the certain time. Repeating steps B1 and B2 allows battery 1 to continuously charge battery 2.

[0225] B3: VB3, VB4, VB7, V`B8, VB11, and VB12 in DCDC power module 2 are turned on, VB1, VB2, VB5, VB6, VB9, and VB10 are turned off, and all switching tubes in DCDC power module 1 are disconnected.

[0226] At this time, battery 2 is discharging, while inductors LB1, LB2, and LB3 in DCDC power module 2 are charging. The battery 2 discharge circuit is: Battery 2 positive electrode → LB1, VB3, VB4 / LB2, VB7, VB8 / LB3, VB11, VB12 → Battery 2 negative electrode. The current flow is shown in Figure 14.

[0227] After the battery 2 charges the inductors LB1, LB2, and LB3 for a certain period of time, the operation of step B4 is performed. The period of time for the battery 2 to charge the inductors LB1, LB2, and LB3 can be included in the heating instruction.

[0228] B4: The switching tubes VA1, VA2, VA5, VA6, VA9, and VA10 in DCDC power module 1 are turned on, and VA3, VA4, VA7, VA8, VA11, and VA12 are turned off; the switching tubes VB1, VB2, VB5, VB6, VB9, and VB10 in DCDC power module 2 are turned on, and VB3, VB4, VB7, VB8, VB11, and VB12 are turned off.

[0229] At this time, battery 2 is discharging and battery 1 is charging. The current loop is: battery 2 positive electrode → LB1, VB2, VB1 / LB2, VB6, VB5 / LB3, VB10, VB9 → VA1, VA2, LA1 / VA5, VA6, LA2 / VA9, VA10, LA3 → battery 1 positive electrode → battery 1 negative electrode → battery 2 negative electrode. The current flow is shown in Figure 15.

[0230] The duration of Battery 2 charging Battery 1 can also be included in the heating instruction. Repeating steps B3 and B4 will enable Battery 2 to continuously charge Battery 1. Repeating steps B1-B4 will enable charging and discharging between cabinets 1 and 2, achieving the function of heating batteries 1 and 2 simultaneously.

[0231] In the charge and discharge circuit shown in Figures 11-15, the structure of the DCDC power modules 1 and 2 can also adopt a single-arm or multi-arm structure with a flying capacitor, as shown in Figure 7.

[0232] Example 2:

[0233] As shown in Figure 16, DCDC power modules 1 and 2 use a three-arm structure without flying capacitors. The first arm of DCDC power module 1 sequentially connects four switches: VA1, VA2, VA3, and VA4. The second arm of DCDC power module 1 sequentially connects four switches: VA5, VA6, VA7, and VA8. The third arm of DCDC power module 1 sequentially connects four switches: VA9, VA10, VA11, and VA12. The connection point between switches VA1 and VA2 is connected to one end of inductor LA1, the connection point between switches VA3 and VA4 is connected to one end of inductor LA2, the connection point between switches VA5 and VA6 is connected to one end of inductor LA3, the connection point between switches VA7 and VA8 is connected to one end of inductor LA4, the connection point between switches VA9 and VA10 is connected to one end of inductor LA5, and the connection point between switches VA11 and VA12 is connected to one end of inductor LA6. The other ends of the inductors LA1 , LA3 , and LA5 are all connected to the positive electrode of the battery 1 , and the other ends of the inductors LA2 , LA4 , and LA6 are all connected to the negative electrode of the battery 1 .

[0234] As shown in Figure 16, the first bridge arm of DCDC power module 2 sequentially connects four switching transistors: VB1, VB2, VB3, and VB4. The second bridge arm of DCDC power module 2 sequentially connects four switching transistors: VB5, VB6, VB7, and VB8. The third bridge arm of DCDC power module 2 sequentially connects four switching transistors: VB9, VB10, VB11, and VB12. The connection point between switching transistors VB1 and VB2 is connected to one end of inductor LB1, the connection point between switching transistors VB3 and VB4 is connected to one end of inductor LB2, the connection point between switching transistors VB5 and VB6 is connected to one end of inductor LB3, the connection point between switching transistors VB7 and VB8 is connected to one end of inductor LB4, the connection point between switching transistors VB9 and VB10 is connected to one end of inductor LB5, and the connection point between switching transistors VB11 and VB12 is connected to one end of inductor LB6. The other ends of inductors LB1, LB3, and LB5 are all connected to the positive terminal of battery 2, and the other ends of inductors LB2, LB4, and LB6 are all connected to the negative terminal of battery 2.

[0235] The first bridge arm of the DCDC power module 1 is close to one end of VA1, the second bridge arm is close to one end of VA5, and the third bridge arm is close to one end of VA9, and the first bridge arm of the DCDC power module 2 is close to one end of VB1, the second bridge arm is close to one end of VB5, and the third bridge arm is close to one end of VB9 are connected in a collinear manner.

[0236] The first bridge arm of the DCDC power module 1 is close to one end of VA4, the second bridge arm is close to one end of VA8, and the third bridge arm is close to one end of VA12, and the first bridge arm of the DCDC power module 2 is close to one end of VB4, the second bridge arm is close to one end of VB8, and the third bridge arm is close to one end of VB12 are connected in a collinear manner.

[0237] As shown in FIG16 , capacitor CA2 is connected in parallel to both ends of battery 1, capacitor CB2 is connected in parallel to both ends of battery 2, capacitor CA1 is connected in parallel to the three bridge arms of DCDC power module 1, and capacitor CB1 is connected in parallel to the three bridge arms of DCDC power module 2.

[0238] Based on the circuit structure shown in FIG16 , the above-mentioned step A5 is followed by the following step C1 .

[0239] C1: The switch tubes VA2, VA3, VA6, VA7, VA10, and VA11 in the DCDC power module 1 are turned on, and VA1, VA4, VA5, VA8, VA9, and VA12 are turned off; all the switch tubes in the DCDC power module 2 are turned off.

[0240] At this time, battery 1 is discharging, while inductors LA1, LA2, LA3, LA4, LA5, and LA6 in the DC-DC power module are charging. The battery 1 discharge circuit is: Battery 1 positive terminal → LA1, VA2, VA3, LA2 / LA3, VA6, VA7, LA4 / LA5, VA10, VA11, LA6 → Battery 1 negative terminal. The current flow is shown in Figure 17.

[0241] After the battery 1 charges the inductors LA1, LA2, LA3, LA4, LA5, and LA6 for a certain period of time, the operation of step C2 is performed. The heating instruction may carry the duration of the battery 1 charging the inductors.

[0242] C2: The switching tubes VA1, VA4, VA5, VA8, VA9, and VA12 in DCDC power module 1 are turned on, and VA2, VA3, VA6, VA7, VA10, and VA11 are turned off; the switching tubes VB1, VB4, VB5, VB8, VB9, and VB12 in DCDC power module 2 are turned on, and VB2, VB3, VB6, VB7, VB10, and VB11 are turned off.

[0243] At this time, battery 1 is discharging and battery 2 is charging. The current loop is: battery 1 positive electrode → LA1, VA1 / LA3, VA5 / LA5, VA9 → VB1, LB1 / VB5, LB3 / VB9, LB5 → battery 2 positive electrode → battery 2 negative electrode → LB6, VB12 / LB4, VB8 / LB2, VB4 → VA4, LA2 / VA8, LA4 / VA12, LA6 → battery 1 negative electrode. The current flow is shown in Figure 18.

[0244] After step C2 is executed for a certain period of time, step C3 is executed. The heating instruction may include the duration for battery 1 to charge battery 2. Repeating steps C1 and C2 can realize the process of battery 1 continuously charging battery 2.

[0245] C3: VB2, VB3, VB6, VB7, VB10, and VB11 in DCDC power module 2 are turned on, and VB1, VB4, VB5, VB8, VB9, and VB12 are turned off; all switching tubes in DCDC power module 1 are turned off.

[0246] At this time, battery 2 is discharging, while inductors LB1, LB2, LB3, LB4, LB5, and LB6 in DCDC power module 2 are charging. The battery 2 discharge circuit is: Battery 2 positive electrode → LB1, VB2, VB3, LB2 / LB3, VB6, VB7, LB4 / LB5, VB10, VB11, LB6 → Battery 2 negative electrode. The current flow is shown in Figure 19.

[0247] After the battery 2 charges the inductor for a certain period of time, the operation of step C4 is performed. The period of time for the battery 2 to charge the inductor may also be included in the heating instruction.

[0248] C4: In DCDC power module 1, VA1, VA4, VA5, VA8, VA9, and VA12 are turned on, and VA2, VA3, VA6, VA7, VA10, and VA11 are turned off; in DCDC power module 2, VB1, VB4, VB5, VB8, VB9, and VB12 are turned on, and VB2, VB3, VB6, VB7, VB10, and VB11 are turned off.

[0249] At this time, battery 2 is discharging and battery 1 is charging. The current loop is: battery 2 positive electrode → LB1, VB1 / LB3, VB5 / LB5, VB9 → VA1, LA1 / VA5, LA3 / VA9, LA5 → battery 1 positive electrode → battery 1 negative electrode → LA2, VA4 / LA4, VA8 / LA6, VA12 → VB4, LB2 / VB8, LB4 / VB12, LB6 → battery 2 negative electrode. The current flow is shown in Figure 20.

[0250] The duration of Battery 2 charging Battery 1 can also be included in the heating instruction. Repeating steps C3 and C4 allows Battery 2 to continuously charge Battery 1. Repeating steps C1-C4 allows charging and discharging between cabinets 1 and 2, achieving the function of heating both batteries 1 and 2 simultaneously.

[0251] In the charge and discharge circuits shown in Figures 16-20, the structure of the DCDC power modules 1 and 2 can also adopt a single-arm or multi-arm structure without a flying capacitor, as shown in Figure 8.

[0252] During the charging and discharging process between the electric cabinet 1 and the electric cabinet 2 shown in the above example 1 or example 2, the following steps are also performed in real time:

[0253] D1: Battery management system 1 determines whether the temperature of battery 1 is abnormal. If so, it sends the temperature abnormality information to LEMS; Battery management system 2 determines whether the temperature of battery 2 is abnormal. If so, it sends the temperature abnormality information to LEMS.

[0254] D2: If LEMS receives abnormal temperature information from battery management system 1 or 2, it sends a stop heating instruction to DCDC power modules 1 and 2 to stop heating.

[0255] During the charging and discharging process between the electric cabinet 1 and the electric cabinet 2 shown in the above example 1 or example 2, the following steps are also performed in real time:

[0256] E1: Battery management system 1 determines whether the temperature of battery 1 reaches the preset required temperature. If so, it sends a temperature compliance information to LEMS; Battery management system 2 determines whether the temperature of battery 2 reaches the preset required temperature. If so, it sends a temperature compliance information to LEMS.

[0257] E2: After LEMS determines that batteries 1 and 2 have reached the preset required temperature, it sends a stop heating instruction to DCDC power modules 1 and 2 to stop heating.

[0258] To further understand the battery self-heating control method in the aforementioned solar-storage system, the control process is illustrated using a flowchart. As shown in Figure 21, when the battery management system is fault-free, it collects the battery's current electrical parameters, such as temperature, SOC, and voltage, and transmits them to the LEMS. The LEMS then determines whether the battery temperature is below a preset low-temperature threshold. If not, the process ends. If so, the LEMS then determines whether the electrical cabinet has a fault based on the electrical parameters. If so, the process ends. If so, the LEMS then determines whether the cabinet has a fault. If so, the process ends. If not, the LEMS controls the switch module to disconnect and sends a heating command to the DC-DC power module in the cabinet. The DC-DC power module, based on the heating command, executes the cabinet's pulse heating mode. The LEMS then determines whether the battery temperature meets a preset abnormality condition. If so, it sends a stop heating command to the DC-DC power module, and the control process ends. If not, the LEMS determines whether the battery temperature has reached a preset target temperature. If so, it sends a stop heating command to the DC-DC power module, and the control process ends. If the preset required temperature is not reached, the DCDC power module returns to the step of executing the electric cabinet pulse heating mode based on the heating instruction control to continue heating.

[0259] In a solar-storage system, when a cabinet is identified that meets preset heating conditions, the switch module is controlled to disconnect, allowing the discharge current from the batteries in the subsequent cabinet to flow to the batteries in other cabinets, creating the structural conditions for forming a charge-discharge loop between cabinets. This inter-cabinet charge-discharge loop allows charging and discharging between cabinets, generating an alternating current flowing through the batteries in multiple cabinets. This causes the internal resistance of the batteries in multiple cabinets to heat simultaneously, achieving simultaneous heating of the batteries in multiple cabinets and improving heating efficiency.

[0260] The present application also provides a battery self-heating control device, which is applied to the energy storage system provided in the above embodiments. The device is used to execute the battery self-heating control method provided in the above embodiments. As shown in FIG22 , the device includes:

[0261] A determination module 201 is configured to determine whether there is at least one target electrical cabinet that meets a preset heating condition;

[0262] The heating module 202 is used to control multiple electrical cabinets including the target electrical cabinet to form a charge-discharge loop, and to charge and discharge the batteries in the target electrical cabinet based on the charge-discharge loop.

[0263] The heating module 202 is used to control the disconnection of the switch module; determine multiple candidate electrical cabinets for forming a charging and discharging circuit, and the multiple candidate electrical cabinets include a target electrical cabinet; control the on and off of power devices in the voltage converters of the multiple candidate electrical cabinets to form an alternating charging circuit and a discharging circuit.

[0264] The heating module 202 is used to determine the electrical cabinets that meet the preset charging and discharging conditions from the remaining electrical cabinets based on the electrical parameters of the batteries in the remaining electrical cabinets except the target electrical cabinet; select at least one electrical cabinet from the electrical cabinets that meet the preset charging and discharging conditions; and determine the target electrical cabinet and the at least one selected electrical cabinet as multiple candidate electrical cabinets for forming a charging and discharging circuit.

[0265] The heating module 202 is used to determine, based on multiple candidate electrical cabinets, the candidate electrical cabinets included in each of at least one charge-discharge circuit to be formed, each charge-discharge circuit including at least one target electrical cabinet that meets preset heating conditions; and to control the on and off of power devices of the voltage converters in the candidate electrical cabinets included in each charge-discharge circuit to form alternating charging and discharging circuits in each charge-discharge circuit.

[0266] The heating module 202 is configured to determine a charge-discharge loop, divide multiple candidate cabinets into a first cabinet group and a second cabinet group, and determine the first cabinet group and the second cabinet group as two cabinet groups of a charge-discharge loop.

[0267] The heating module 202 is used to determine the formation of multiple charging and discharging circuits, where the number of the multiple charging and discharging circuits is less than or equal to the number of target cabinets; divide the multiple candidate cabinets into multiple groups of cabinets, each group of cabinets including at least two candidate cabinets; and determine the multiple groups of cabinets as candidate cabinets included in each of the multiple charging and discharging circuits.

[0268] The heating module 202 is used to send a heating instruction to the voltage converter of the electrical cabinet in the first charge and discharge circuit, where the first charge and discharge circuit is any one of each charge and discharge circuit; based on the heating instruction, the charging circuit and the discharging circuit in the first charge and discharge circuit are controlled to form alternating switching.

[0269] The heating module 202 is used to send a heating instruction to the voltage converter of each electrical cabinet in the first charge and discharge circuit; or, send a heating instruction to the voltage converter of the target electrical cabinet in the first charge and discharge circuit; and forward the heating instruction to the voltage converters of other electrical cabinets in the first charge and discharge circuit through the voltage converter of the target electrical cabinet.

[0270] In an embodiment of the present application, the first charging and discharging circuit includes a first subset of electrical cabinets and a second subset of electrical cabinets, and the battery power corresponding to the first subset of electrical cabinets is greater than the battery power corresponding to the second subset of electrical cabinets; the heating module 202 is used to control, based on a heating instruction, in the first stage to form a circuit in which the batteries of each electrical cabinet in the first set of electrical cabinets charge the batteries of each electrical cabinet in the second set of electrical cabinets; and in the second stage to control the formation of a circuit in which the batteries of each electrical cabinet in the second set of electrical cabinets charge the batteries of each electrical cabinet in the first set of electrical cabinets.

[0271] In other embodiments, the first charging and discharging circuit includes a first subset of electrical cabinets and a second subset of electrical cabinets, and the battery power corresponding to the first subset of electrical cabinets is equal to the battery power corresponding to the second subset of electrical cabinets; the heating module 202 is used to control, based on the heating instruction, in the first stage, to form a circuit in which the batteries of each electrical cabinet in the first subset of electrical cabinets charge the energy storage elements of the voltage converters in their respective electrical cabinets; in the second stage, to control the formation of a circuit in which the batteries of each electrical cabinet in the first subset of electrical cabinets and the energy storage elements of the voltage converters charge the batteries of each electrical cabinet in the second subset of electrical cabinets; in the third stage, to control the formation of a circuit in which the batteries of each electrical cabinet in the second subset of electrical cabinets charge the energy storage elements of the voltage converters in their respective electrical cabinets; and in the fourth stage, to control the formation of a circuit in which the batteries of each electrical cabinet in the second subset of electrical cabinets and the energy storage elements of the voltage converters charge the batteries of each electrical cabinet in the first subset of electrical cabinets.

[0272] The heating module 202 is configured to control the first electrical cabinet subset to charge the second electrical cabinet subset for a shorter time than the second electrical cabinet subset to charge the first electrical cabinet subset when the number of batteries included in the first electrical cabinet subset is greater than the number of batteries included in the second electrical cabinet subset.

[0273] The device also includes: a heating condition judgment module, which is used to obtain the electrical parameters of the batteries in each electric cabinet; based on the electrical parameters of the batteries in each electric cabinet, determine whether there is a target electric cabinet that meets the preset heating conditions.

[0274] The device also includes: a stop control module, which is used to determine whether a preset stop heating condition is met based on the electrical parameters of the battery in each electrical cabinet included in the charging and discharging circuit; if it is determined that the preset stop heating condition is met, a stop heating instruction is sent to the voltage converter of the electrical cabinet in the charging and discharging circuit.

[0275] The battery self-heating control device provided in the above-mentioned embodiment of the present application and the battery self-heating control method provided in the embodiment of the present application are based on the same inventive concept and have the same beneficial effects as the methods adopted, run or implemented by the application programs stored therein.

[0276] Figure 23 shows a schematic block diagram of an electronic device 700 according to an embodiment of the present application. As shown in Figure 7 , the electronic device 700 includes a processor 710. Optionally, the electronic device 700 also includes a memory 720, wherein the memory 720 is used to store a computer program, and the processor 710 is used to read the computer program and execute the battery self-heating control method according to the various embodiments of the present application described above based on the computer program. The electronic device may include a system controller for the energy storage system, a voltage converter in the electrical cabinet, a battery management system, and the like.

[0277] An embodiment of the present application further provides a computer-readable storage medium for storing a computer program, which, when executed by a processor, implements the methods of the various embodiments of the present application described above.

[0278] An embodiment of the present application further provides a computer program product, including a computer program, which is executed by a processor to implement the methods of the various embodiments of the present application described above.

[0279] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0280] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0281] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0282] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of the solution of this embodiment according to actual needs.

[0283] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0284] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0285] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. An energy storage system, characterized in that: Includes system controller, switch module and multiple electrical cabinets; The multiple electrical cabinets are connected in parallel, one end of the switch module is connected to the high-voltage bus, and the other end is connected to the connection point of the multiple electrical cabinets in parallel; The system controller is respectively in communication with the switch module and each electrical cabinet; The system controller is used to control the formation of a charging and discharging circuit between the multiple electric cabinets when there is an electric cabinet that meets the preset heating conditions among the multiple electric cabinets.

2. The energy storage system according to claim 1, characterized in that The electrical cabinet includes batteries, a battery management system and a voltage converter; The battery management system, the system controller and the voltage converter are all communicatively connected.

3. The energy storage system according to claim 2, characterized in that: The battery management system is used to detect electrical parameters of the battery and transmit the electrical parameters to the system controller; The system controller is configured to control the switch module to disconnect when it is determined based on the electrical parameters that the electrical cabinet meets a preset heating condition.

4. The energy storage system according to any one of claims 1 to 3, characterized in that: The system controller is configured to send a heating instruction to at least one electric cabinet when there is an electric cabinet meeting the preset heating condition among the plurality of electric cabinets, wherein the at least one electric cabinet includes the electric cabinet meeting the preset heating condition; The at least one electric cabinet is used to construct a charge-discharge loop between the electric cabinets based on the heating instruction, and control the batteries in the charge-discharge loop to charge and discharge alternately.

5. The energy storage system according to claim 2 or 3, characterized in that: The voltage converter includes at least one bridge arm having a flying capacitor and at least one energy storage element, wherein the bridge arm corresponds to the energy storage element in a one-to-one manner; One end of the energy storage element is connected to the positive electrode of the battery in the electrical cabinet to which the voltage converter belongs, and the other end of the energy storage element is connected to the connection point of the upper bridge arm and the lower bridge arm in the bridge arm corresponding to the energy storage element.

6. The energy storage system according to claim 2 or 3, characterized in that: The voltage converter includes at least one bridge arm without a flying capacitor and at least two energy storage elements, and each bridge arm is connected to two energy storage elements respectively; The bridge arm includes at least four switching tubes connected in sequence; the positive and negative poles of the battery in the electric cabinet to which the voltage converter belongs are respectively connected to the two energy storage elements connected to the bridge arm.

7. A battery self-heating control method, characterized in that: Applied to the energy storage system according to any one of claims 1 to 6, the method comprises: Determining that there is at least one target electrical cabinet that meets a preset heating condition; A plurality of electric cabinets including the target electric cabinet are controlled to form a charge-discharge loop, and batteries in the target electric cabinet are charged and discharged based on the charge-discharge loop.

8. The method according to claim 7, characterized in that The controlling of multiple electrical cabinets including the target electrical cabinet to form a charge-discharge circuit includes: Controlling the switch module to disconnect; Determining a plurality of candidate electrical cabinets for forming a charge-discharge loop, wherein the plurality of candidate electrical cabinets include the target electrical cabinet; The power devices in the voltage converters of the plurality of candidate electrical cabinets are controlled to be turned on and off, so as to form an alternating charging circuit and a discharging circuit.

9. The method according to claim 8, characterized in that The step of determining a plurality of candidate electrical cabinets for forming a charge-discharge circuit includes: Based on the electrical parameters of the batteries in the remaining electrical cabinets except the target electrical cabinet, determining the electrical cabinet that meets the preset charge and discharge conditions from the remaining electrical cabinets; Select at least one electric cabinet from electric cabinets that meet preset charging and discharging conditions; The target electric cabinet and the selected at least one electric cabinet are determined as a plurality of candidate electric cabinets for constituting a charge-discharge loop.

10. The method according to claim 8, characterized in that The controlling of the on and off of power devices in the voltage converters of the plurality of candidate electrical cabinets to form an alternatingly switched charging circuit and a discharging circuit includes: Determining, based on the multiple candidate electrical cabinets, candidate electrical cabinets included in each of at least one charge-discharge circuit to be formed, wherein each charge-discharge circuit includes at least one target electrical cabinet that meets a preset heating condition; The on and off of power devices of the voltage converters in the candidate electrical cabinets included in each charge and discharge circuit are controlled respectively to form an alternatingly switched charging circuit and discharging circuit in each charge and discharge circuit.

11. The method according to claim 10, characterized in that The determining, based on the plurality of candidate electrical cabinets, a candidate electrical cabinet included in each charging and discharging circuit of at least one charging and discharging circuit to be formed comprises: Determine to form a charge-discharge loop, and divide the plurality of candidate electric cabinets into a first electric cabinet group and a second electric cabinet group; The first electric cabinet group and the second electric cabinet group are determined as two groups of electric cabinets for the one charging and discharging circuit.

12. The method according to claim 10, characterized in that The determining, based on the plurality of candidate electrical cabinets, a candidate electrical cabinet included in each charging and discharging circuit of at least one charging and discharging circuit to be formed comprises: Determining to constitute a plurality of charge-discharge circuits, where the number of the plurality of charge-discharge circuits is less than or equal to the number of the target electrical cabinets; Dividing the plurality of candidate electrical cabinets into a plurality of groups of electrical cabinets, each group of electrical cabinets including at least two candidate electrical cabinets; The multiple groups of electric cabinets are respectively determined as candidate electric cabinets included in each of the multiple charging and discharging circuits.

13. The method according to claim 10, characterized in that The method of controlling the on and off of power devices of the voltage converter in the candidate electrical cabinet included in each charging and discharging circuit to form an alternatingly switched charging circuit and discharging circuit in each charging and discharging circuit includes: Sending a heating instruction to a voltage converter of an electrical cabinet in a first charge-discharge circuit, where the first charge-discharge circuit is any one of the charge-discharge circuits; Based on the heating instruction, the first charge and discharge circuit is controlled to form a charging circuit and a discharging circuit that are alternately switched.

14. The method according to claim 13, characterized in that The step of sending a heating instruction to a voltage converter of an electrical cabinet in the first charge-discharge circuit includes: A heating instruction is sent to the voltage converter of each electrical cabinet in the first charge and discharge loop.

15. The method according to claim 13, characterized in that The step of sending a heating instruction to a voltage converter of an electrical cabinet in the first charge-discharge circuit includes: sending a heating instruction to a voltage converter of a target electrical cabinet in a first charge-discharge loop; The heating instruction is forwarded to the voltage converters of other electrical cabinets in the first charge and discharge loop through the voltage converter of the target electrical cabinet.

16. The method according to claim 13, characterized in that The first charge and discharge circuit includes a first subset of electric cabinets and a second subset of electric cabinets, and the battery power corresponding to the first subset of electric cabinets is greater than the battery power corresponding to the second subset of electric cabinets; The step of controlling the first charge-discharge circuit to form an alternating charging circuit and a discharging circuit based on the heating instruction includes: Based on the heating instruction, in the first stage, a control is performed to form a circuit for charging the batteries of each electric cabinet in the first electric cabinet set to the batteries of each electric cabinet in the second electric cabinet set; In the second stage, a control loop is formed for the batteries of each electric cabinet in the second electric cabinet set to charge the batteries of each electric cabinet in the first electric cabinet set.

17. The method according to claim 13, wherein The first charge and discharge circuit includes a first electric cabinet subset and a second electric cabinet subset, and the battery power corresponding to the first electric cabinet subset is equal to the battery power corresponding to the second electric cabinet subset; The step of controlling the first charge-discharge circuit to form an alternating charging circuit and a discharging circuit based on the heating instruction includes: Based on the heating instruction, in the first stage, a control is performed to form a circuit in which the batteries of each electric cabinet in the first subset of electric cabinets charge the energy storage elements of the voltage converters in the respective electric cabinets; In the second stage, a circuit is formed by controlling the batteries of each electric cabinet in the first electric cabinet set and the energy storage element of the voltage converter to charge the batteries of each electric cabinet in the second electric cabinet set; In the third stage, a control circuit is formed for the batteries of each electric cabinet in the second electric cabinet subset to charge the energy storage elements of the voltage converters in the respective electric cabinets; In the fourth stage, a circuit is controlled to form a circuit in which the batteries of each electric cabinet in the second electric cabinet set and the energy storage elements of the voltage converter charge the batteries of each electric cabinet in the first electric cabinet set.

18. The method according to claim 16 or 17, characterized in that The method further comprises: When the number of batteries included in the first cabinet subset is greater than the number of batteries included in the second cabinet subset, the duration for which the first cabinet subset charges the second cabinet subset is controlled to be shorter than the duration for which the second cabinet subset charges the first cabinet subset.

19. The method according to any one of claims 7 to 17, characterized in that: The method further comprises: Obtain the electrical parameters of the batteries in each electrical cabinet; Based on the electrical parameters of the batteries in each electrical cabinet, it is determined whether there is a target electrical cabinet that meets the preset heating conditions.

20. The method according to any one of claims 7 to 17, characterized in that After charging and discharging the battery in the target electrical cabinet based on the charge-discharge circuit, the method further includes: Based on the electrical parameters of the batteries in each electrical cabinet included in the charge-discharge circuit, determining whether a preset heating stop condition is met; When it is determined that the preset heating stop condition is met, a heating stop instruction is sent to the voltage converter of the electrical cabinet in the charge-discharge circuit.

21. A battery self-heating control device, characterized in that: Applicable to the energy storage system according to any one of claims 1 to 6, the device comprising: A determination module, configured to determine whether there is at least one target electrical cabinet that meets a preset heating condition; The heating module is used to control multiple electric cabinets including the target electric cabinet to form a charge-discharge loop, and to charge and discharge the battery in the target electric cabinet based on the charge-discharge loop.

22. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the method according to any one of claims 7 to 20 is implemented.

23. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 7 to 20 is implemented.

24. A computer program product comprising a computer program, characterized in that The computer program is executed by a processor to implement the method according to any one of claims 7 to 20.

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