Energy storage systems and their control methods, controllers, battery clusters and energy storage components

Abstract

This application provides an energy storage system and its control method, controller, battery cluster, and energy storage component. The energy storage system includes at least one primary energy storage unit, and each primary energy storage unit includes at least one energy storage component. The energy storage component includes at least one secondary energy storage unit, a DC / DC converter, and a first capacitor. The at least one secondary energy storage unit and the first capacitor are connected in series. The positive and negative terminals of the first end of the DC / DC converter are respectively connected to the two ends of the at least one secondary energy storage unit, and the positive and negative terminals of the second end of the DC / DC converter are respectively connected to the two ends of the first capacitor. In this energy storage system, the DC / DC converter only needs to process a portion of the power, and the remaining power is directly transmitted through low-impedance wires. Therefore, the losses of the internal components of the DC / DC converter can be reduced, while the energy transmission efficiency of the system can be improved.

Description

Technical Field

[0001] This application relates to the field of energy storage system technology, and in particular to energy storage systems and their control methods, controllers, battery clusters and energy storage components. Background Technology

[0002] With the widespread application of renewable energy and the increasing demand for energy management, energy storage systems have become an important component of modern power systems. Energy storage systems balance power supply and demand by storing electrical energy and providing energy during peak demand periods, thereby improving system stability and reliability.

[0003] Energy storage systems typically employ multiple parallel energy storage units. To regulate the voltage and balance the energy among these units, a scheme involving connecting the energy storage units in series with a DC / DC converter can be used to achieve output voltage regulation and energy balancing among the parallel energy storage units. However, this results in higher losses in the internal components of the DC / DC converter and also affects the system's energy transfer efficiency. Summary of the Invention

[0004] The purpose of this application is to provide an energy storage system and its control method, controller, battery cluster and energy storage components, to reduce the losses of internal components of DC / DC converters, and at the same time improve the energy transfer efficiency of the system.

[0005] The objective of this application is achieved through the following technical solution:

[0006] In a first aspect, embodiments of this application provide an energy storage system, the energy storage system including at least one primary energy storage unit, the primary energy storage unit including at least one energy storage component; the energy storage component including at least one secondary energy storage unit, a DC / DC converter and a first capacitor, the at least one secondary energy storage unit and the first capacitor being connected in series, the positive and negative terminals of the first terminal of the DC / DC converter being respectively connected to the two terminals of the at least one secondary energy storage unit, and the positive and negative terminals of the second terminal of the DC / DC converter being respectively connected to the two terminals of the first capacitor.

[0007] In some embodiments, when the number of primary energy storage units in the energy storage system is greater than 1, multiple primary energy storage units are connected in parallel.

[0008] In some embodiments, when the number of energy storage components in the primary energy storage unit is greater than 1, multiple energy storage components are connected in series.

[0009] In some embodiments, when the number of secondary energy storage units in the energy storage component is greater than 1, multiple secondary energy storage units are connected in series.

[0010] In some embodiments, in the event of a high-voltage ride-through in the energy storage system, the voltage of the corresponding first capacitor is adjusted by at least a portion of the DC / DC converter in the primary energy storage unit to regulate the voltage of the primary energy storage unit.

[0011] In some embodiments, at least a portion of the energy storage components further includes a bypass switch, the two ends of which are respectively connected to the positive and negative terminals of the second terminal of the DC / DC converter; the bypass switch is closed to disable the corresponding DC / DC converter; or the bypass switch is open to enable the corresponding DC / DC converter to operate.

[0012] In some embodiments, in the event of a high-voltage ride-through in the energy storage system, at least a portion of the bypass switches are controlled to disconnect, thereby enabling the corresponding DC / DC converter to operate.

[0013] In some embodiments, if the energy storage system is not faulty, at least a portion of the bypass switches are closed to disable the corresponding DC / DC converter.

[0014] In some embodiments, the number of energy storage components in the primary energy storage unit is 1, and the number of secondary energy storage units in the energy storage components is greater than 1.

[0015] In some embodiments, when the voltage of the primary energy storage unit needs to be regulated, the voltage of the corresponding first capacitor is adjusted by a DC / DC converter to regulate the voltage of the primary energy storage unit.

[0016] In some embodiments, when the energy storage system needs to discharge, the voltage of the corresponding first capacitor is adjusted by the DC / DC converter in each energy storage component so that the discharge power of each primary energy storage unit is positively correlated with the battery state of charge; or, when the energy storage system needs to charge, the voltage of the corresponding first capacitor is adjusted by the DC / DC converter in each energy storage component so that the charging power of each primary energy storage unit is negatively correlated with the battery state of charge.

[0017] In some embodiments, the number of energy storage components in the primary energy storage unit is greater than 1, and the number of secondary energy storage units in the energy storage components is 1.

[0018] In some embodiments, when the energy storage component requires voltage regulation, the voltage of the corresponding first capacitor is adjusted by the DC / DC converter in the energy storage component to regulate the voltage of the energy storage component.

[0019] In some embodiments, when the energy storage system needs to discharge, in the first-level energy storage unit, the corresponding first current is adjusted by the DC / DC converter in each energy storage component so that the discharge power of each energy storage component is positively correlated with the battery state of charge; or, when the energy storage system needs to charge, in the first-level energy storage unit, the corresponding first current is adjusted by the DC / DC converter in each energy storage component so that the charging power of each energy storage component is negatively correlated with the battery state of charge.

[0020] In some embodiments, when the energy storage system needs to discharge, in each primary energy storage unit, the voltage of the corresponding first capacitor is adjusted by the DC / DC converter in each energy storage component so that the discharge power of each primary energy storage unit is positively correlated with the battery state of charge; or, when the energy storage system needs to charge, in each primary energy storage unit, the voltage of the corresponding first capacitor is adjusted by the DC / DC converter in each energy storage component so that the charging power of each primary energy storage unit is negatively correlated with the battery state of charge.

[0021] In some embodiments, the DC / DC converter includes one or more of non-isolated and isolated topologies.

[0022] In some embodiments, the primary energy storage unit further includes a first switch, which is connected in series with the at least one energy storage component.

[0023] In some embodiments, the primary energy storage unit is a battery cluster, and the secondary energy storage unit is a battery pack.

[0024] Secondly, embodiments of this application provide a control method for an energy storage system, applicable to any of the aforementioned energy storage systems. The method includes: when a primary energy storage unit requires voltage regulation, adjusting the voltage of a corresponding first capacitor through at least a portion of the DC / DC converters in the primary energy storage unit to regulate the voltage of the primary energy storage unit; or, when energy balancing is required among the primary energy storage units, adjusting the voltage of a corresponding first capacitor through at least a portion of the DC / DC converters in each primary energy storage unit, so that the discharge power of each primary energy storage unit in the discharge state is positively correlated with the battery's state of charge, or that the charging power of each primary energy storage unit in the charging state is negatively correlated with the battery's state of charge; or, in the primary energy storage unit, when energy balancing is required among the energy storage components, adjusting a corresponding first current through the DC / DC converters in each energy storage component, so that the discharge power of each energy storage component in the discharge state is positively correlated with the battery's state of charge, or that the charging power of each energy storage component in the charging state is negatively correlated with the battery's state of charge.

[0025] Thirdly, embodiments of this application provide a controller, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement any of the methods described above.

[0026] Fourthly, embodiments of this application provide a battery cluster, the battery cluster including multiple battery packs, a DC / DC converter and a first capacitor, the multiple battery packs and the first capacitor being connected in series, the positive and negative terminals of the first end of the DC / DC converter being respectively connected to the two ends of the multiple battery packs, and the positive and negative terminals of the second end of the DC / DC converter being respectively connected to the two ends of the first capacitor.

[0027] Fifthly, embodiments of this application provide an energy storage component, the energy storage component including a battery pack, a DC / DC converter and a first capacitor, the battery pack and the first capacitor being connected in series, the positive and negative terminals of the first end of the DC / DC converter being connected to the two ends of the battery pack respectively, and the positive and negative terminals of the second end of the DC / DC converter being connected to the two ends of the first capacitor respectively.

[0028] This application provides an energy storage system and its control method, controller, battery cluster, and energy storage component. The energy storage system includes at least one primary energy storage unit, and each primary energy storage unit includes at least one energy storage component. The energy storage component includes at least one secondary energy storage unit, a DC / DC converter, and a first capacitor. The at least one secondary energy storage unit and the first capacitor are connected in series. The positive and negative terminals of the first end of the DC / DC converter are respectively connected to the two ends of the at least one secondary energy storage unit, and the positive and negative terminals of the second end of the DC / DC converter are respectively connected to the two ends of the first capacitor. In the above-mentioned energy storage system, the DC / DC converter only needs to process a portion of the power, and the remaining power is directly transmitted through low-impedance wires. Only a portion of the current flows through the DC / DC converter, thus reducing the losses of the internal components of the DC / DC converter and improving the energy transmission efficiency of the system. Attached Figure Description

[0029] This application will be further described below with reference to the accompanying drawings and specific embodiments.

[0030] Figure 1 This is a structural block diagram of an energy storage battery system connected to a DC / DC converter, provided in an embodiment of this application.

[0031] Figure 2 This is a schematic diagram of the power flow direction of a partial power conversion topology provided in an embodiment of this application.

[0032] Figure 3 This is a structural block diagram of an energy storage component provided in an embodiment of this application.

[0033] Figure 4 This is a structural block diagram of an energy storage system provided in an embodiment of this application.

[0034] Figure 5 This is one of the embodiments provided in this application. Figure 4 A schematic diagram of voltage regulation of the energy storage components.

[0035] Figure 6a This is one of the embodiments provided in this application. Figure 4 A schematic diagram of the discharge power adjustment of the energy storage system.

[0036] Figure 6b This is one of the embodiments provided in this application. Figure 4 A schematic diagram of the charging power adjustment of the energy storage system.

[0037] Figure 7 This is a structural block diagram of another energy storage system provided in the embodiments of this application.

[0038] Figure 8 This is one of the embodiments provided in this application. Figure 7 A schematic diagram of voltage regulation of the energy storage components.

[0039] Figure 9a This is one of the embodiments provided in this application. Figure 7 A schematic diagram of the current direction of the energy storage component in discharge mode.

[0040] Figure 9b This is one of the embodiments provided in this application. Figure 7 A schematic diagram of the current direction of the energy storage component in charging mode.

[0041] Figure 10a This is one of the embodiments provided in this application. Figure 7 A schematic diagram of the discharge power adjustment of the energy storage system.

[0042] Figure 10b This is one of the embodiments provided in this application. Figure 7 A schematic diagram of the charging power adjustment of the energy storage system.

[0043] Figure 11 This is a flowchart illustrating a control method for an energy storage system provided in an embodiment of this application.

[0044] Figure 12 This is a structural block diagram of a controller provided in an embodiment of this application. Detailed Implementation

[0045] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0046] In the description of the embodiments of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0047] See Figure 1 , Figure 1 This is a structural block diagram of an energy storage battery system connected to a DC / DC converter, as provided in an embodiment of this application. Figure 1 In this diagram, RACK1 to RACKn represent battery clusters (as an example of an energy storage unit), DC / DC is a DC / DC converter, DC / AC is a DC / AC converter, BUS is the DC bus, BUS+ is the positive terminal of the DC bus, and BUS- is the negative terminal of the DC bus. Here, DC stands for Direct Current, and DC / DC is a DC-to-DC converter; AC stands for Alternating Current, and DC / AC is a DC-to-AC converter.

[0048] See Figure 2 , Figure 2 This is a schematic diagram of the power flow direction of a partial power conversion topology provided in an embodiment of this application. Figure 2 In the middle, P in For input power, P out For output power, P main P represents the portion of the power transmitted through the wire. DC / DC This refers to the portion of power transmitted through a partial power conversion topology.

[0049] See Figure 3 , Figure 3 This is a structural block diagram of an energy storage component provided in an embodiment of this application. Figure 3 In the diagram, BAT represents the secondary energy storage unit, and C represents the first capacitor.

[0050] To reduce the losses of internal components in a DC / DC converter and improve the energy transfer efficiency of the system, this application provides an energy storage system. The energy storage system includes at least one primary energy storage unit, and the primary energy storage unit includes at least one energy storage component. The energy storage component includes at least one secondary energy storage unit, a DC / DC converter, and a first capacitor. The at least one secondary energy storage unit and the first capacitor are connected in series. The positive and negative terminals of the first end of the DC / DC converter are respectively connected to the two ends of the at least one secondary energy storage unit, and the positive and negative terminals of the second end of the DC / DC converter are respectively connected to the two ends of the first capacitor.

[0051] In the above embodiment, the DC / DC converter has a first terminal and a second terminal, with the first terminal connected to a secondary energy storage unit and the second terminal connected to a first capacitor. This DC / DC converter processes a portion of the power and can therefore be called a partial-power DC / DC converter. Compared to a full-power conversion topology, a partial-power conversion topology does not need to process all the power, thus reducing costs. As an example, the power processing range of a partial-power conversion topology can be smaller than a first power range. This first power range can be selected or set according to actual needs, for example, it can be the power range that a full-power conversion topology can operate in, or a power range obtained through other means.

[0052] The above embodiments do not limit the hierarchical division of energy storage units. In some embodiments, the primary energy storage unit can be a battery cluster, and the secondary energy storage unit can be a battery pack. It should be noted that, in this document, a battery cluster, as a primary energy storage unit, can contain one or more energy storage components; the energy storage components can contain one or more battery packs (as an example of a secondary energy storage unit).

[0053] The above embodiments do not limit the number of primary energy storage units, energy storage components, and secondary energy storage units; each can be one or more. In some embodiments, when the number of primary energy storage units in the energy storage system is greater than one, multiple primary energy storage units can be connected in parallel. In some embodiments, when the number of energy storage components in the primary energy storage units is greater than one, multiple energy storage components can be connected in series. In some embodiments, when the number of secondary energy storage units in the energy storage components is greater than one, multiple secondary energy storage units can be connected in series.

[0054] Compared to a scheme where both ends of the battery pack are connected to the positive and negative input terminals of a DC / DC converter, the DC / DC converter in the aforementioned energy storage system only needs to process a portion of the power. The remaining power is transmitted directly through low-impedance wires, with only a portion of the current flowing through the DC / DC converter. This reduces losses in the internal components of the DC / DC converter and improves the system's energy transfer efficiency. Furthermore, since the DC / DC converter only processes a portion of the power, losses during energy equalization are reduced, improving equalization efficiency.

[0055] In some embodiments, in addition to the at least one primary energy storage unit described above, the energy storage system may also include at least one first energy storage unit. The first energy storage unit may, for example, adopt a scheme in which the two ends of the battery pack are connected to the positive and negative terminals of the input terminal of the DC / DC converter. That is, the DC / DC converter can be applied in a full-power conversion topology, and the above embodiments do not limit this.

[0056] The above embodiments do not limit the isolation topology type of the DC / DC converter. In some embodiments, the DC / DC converter may include one or more of non-isolated and isolated topologies. As an example, all DC / DC converters in the energy storage system may use a non-isolated topology. As another example, all DC / DC converters in the energy storage system may use an isolated topology. As yet another example, some DC / DC converters in the energy storage system may use a non-isolated topology, while the remaining DC / DC converters may use an isolated topology.

[0057] In practical applications, partial-power DC / DC converters can use either non-isolated or isolated topologies. For example, a partial-power DC / DC converter using an isolated topology can incorporate an isolation transformer. Energy storage systems have low requirements for source-load electrical isolation, a relatively narrow voltage transformation range, and allow the negative terminal to be ungrounded. Therefore, the DC / DC converters in these energy storage systems can use non-isolated topologies to achieve higher conversion efficiency and power density. Furthermore, compared to partial-power DC / DC converters using isolated topologies, non-isolated topologies reduce the use of isolation transformers, resulting in lower cost and smaller size.

[0058] The above embodiments do not limit the isolation topology used in the DC / DC converter. It may include, for example, one or more of a flyback converter, an LLC resonant converter (inductor-inductor-capacitor resonant converter), and a dual active bridge converter. In addition to these topologies themselves, improved topologies may also be included. The above embodiments do not limit the non-isolated topology used in the DC / DC converter. It may include, for example, one or more of a bidirectional boost circuit, a bidirectional buck circuit, and a bidirectional buck-boost circuit. In addition to these topologies themselves, derived topologies may also be included.

[0059] Energy storage systems may face high-voltage ride-through conditions during operation, such as voltage rises caused by grid faults or disturbances. Within a certain voltage rise range and time interval, the energy storage system needs to ensure continuous operation without disconnecting from the grid. To effectively cope with high-voltage ride-through conditions, in some embodiments, when a high-voltage ride-through occurs, the voltage of the corresponding first capacitor is adjusted by at least a portion of the DC / DC converters in the first-level energy storage unit, thereby regulating the voltage of the first-level energy storage unit. The advantage of this is that when a high-voltage ride-through occurs, the DC / DC converters can be controlled to operate, ensuring that the voltage of the corresponding first capacitor is greater than 0, thus raising the voltage of the corresponding first-level energy storage unit, thereby suppressing the high-voltage ride-through and ensuring that the energy storage system can operate continuously without disconnecting from the grid.

[0060] To reduce losses in the DC / DC converter, in some embodiments, at least a portion of the energy storage component may also include a bypass switch, the two ends of which are respectively connected to the positive and negative terminals of the second terminal of the DC / DC converter; the bypass switch is closed to disable the corresponding DC / DC converter; or the bypass switch is open to enable the corresponding DC / DC converter to operate.

[0061] The above embodiments do not limit the bypass switch, which may include one or more of DC relays and switching transistors. Its function is, for example, to switch the DC / DC converter on and off according to the actual operating conditions, so as to realize the non-full-cycle operation of the DC / DC converter and thus improve the overall system efficiency.

[0062] As one example, all energy storage components in the energy storage system are equipped with bypass switches, allowing all DC / DC converters to operate non-full-cycle. As another example, none of the energy storage components in the energy storage system are equipped with bypass switches, allowing all DC / DC converters to operate full-cycle. As yet another example, some energy storage components in the energy storage system are equipped with bypass switches, allowing their DC / DC converters to operate non-full-cycle; the remaining energy storage components are not equipped with bypass switches, allowing their DC / DC converters to operate full-cycle. Therefore, the choice of whether to install bypass switches can be made based on actual needs. On the one hand, installing bypass switches can improve the overall system efficiency; if full-cycle operation is required, the bypass switches can be removed without affecting the normal operation of the DC / DC converters.

[0063] For energy storage components equipped with a bypass switch, since the bypass switch is connected in parallel with the second terminal of the DC / DC converter (e.g., the two ends of the bypass switch are connected to the positive and negative terminals of the second terminal of the DC / DC converter), the bypass switch can be used to switch the DC / DC converter on and off, so that the DC / DC converter does not need to operate for the entire cycle. This reduces the operating time of the DC / DC converter, thereby reducing the losses of the internal components of the DC / DC converter.

[0064] To effectively handle high-voltage ride-through conditions, DC / DC converters are required to operate and perform voltage regulation. Therefore, if the energy storage module is equipped with a bypass switch, this bypass switch needs to be disconnected. In some embodiments, when a high-voltage ride-through occurs in the energy storage system, at least some bypass switches can be controlled to disconnect, thereby activating the corresponding DC / DC converters. The advantage of this is that, during a high-voltage ride-through, at least some bypass switches can be disconnected, causing the corresponding DC / DC converters to operate, resulting in a voltage greater than 0 for the corresponding first capacitor and a voltage increase for the corresponding first-stage energy storage unit. This suppresses high-voltage ride-through and ensures the energy storage system can operate continuously without disconnecting from the grid.

[0065] In the absence of a fault, the bypass switch can be closed to disable the corresponding DC / DC converter. In some embodiments, when the energy storage system is fault-free, at least some bypass switches can be controlled to close to disable the corresponding DC / DC converter. The advantage of this is that, under normal operating conditions (e.g., no high-voltage ride-through, low-voltage ride-through, or other faults), at least some bypass switches can be controlled to disable the corresponding DC / DC converter. Power is transferred through the bypass switch and wires without passing through the DC / DC converter, thereby reducing losses in the internal components of the DC / DC converter and improving system efficiency.

[0066] To enable switching of primary energy storage units, in some embodiments, the primary energy storage unit may further include a first switch, which is connected in series with the at least one energy storage component. This allows the corresponding primary energy storage unit to be disconnected in the event of a failure.

[0067] The above embodiments do not limit the source of the control signals used to control the on and off of each switch (e.g., bypass switch, first switch), which may be, for example, a battery cluster management unit, a battery pack management unit, a battery management system, a local controller, an energy storage converter, etc.

[0068] See Figure 4 , Figure 4 This is a structural block diagram of an energy storage system provided in an embodiment of this application. Figure 4 In this configuration, m primary energy storage units are connected in parallel. K1 to Km are the first switches, used to disconnect the primary energy storage unit that has failed. BAT11 to BAT1n...

[0069] BATm1 to BATmn are secondary energy storage units, C11 to Cm1 are first capacitors, and K11 to Km1 are bypass switches. The secondary energy storage units BAT11 to BAT1n, the DC / DC converter, the first capacitor C11, and the bypass switch K11 form an energy storage module. This energy storage module and the first switch K1 form a primary energy storage unit. Similarly, the secondary energy storage units BATm1 to BATmn, the DC / DC converter, the first capacitor Cm1, and the bypass switch Km1 form an energy storage module. This energy storage module and the first switch Km form a primary energy storage unit.

[0070] like Figure 4 As shown, in some embodiments, the number of energy storage components in the primary energy storage unit can be 1, and the number of secondary energy storage units in the energy storage components can be greater than 1.

[0071] In some embodiments, when voltage regulation is required for the primary energy storage unit, the voltage of the corresponding first capacitor can be adjusted via a DC / DC converter to regulate the voltage of the primary energy storage unit. Thus, the voltage of the first capacitor can be adjusted via the DC / DC converter, thereby achieving voltage regulation of the primary energy storage unit.

[0072] In the above embodiments, when the primary energy storage unit requires voltage regulation, if some or all of the energy storage components are equipped with bypass switches, at least some of the bypass switches can be disconnected to allow the corresponding DC / DC converter to operate. Conversely, when the primary energy storage unit does not require voltage regulation, if some or all of the energy storage components are equipped with bypass switches, at least some of the bypass switches can be closed to disable the corresponding DC / DC converter, thereby reducing the losses of the internal components of the DC / DC converter.

[0073] See Figure 5 , Figure 5 This is one of the embodiments provided in this application. Figure 4 A schematic diagram of voltage regulation for the energy storage components. Figure 5 In the middle, V BAT V represents the corresponding battery voltages of the secondary energy storage units BATm1 to BATmn. Cm1 V is the voltage across the first capacitor Cm1. rack V is the voltage of the energy storage component. Since the primary energy storage unit containing this energy storage component consists of only one energy storage component, therefore, V rack It is also the voltage of the first-level energy storage unit.

[0074] For example, suppose the primary energy storage unit has a bypass switch. When the primary energy storage unit does not require voltage regulation, to reduce the losses of the internal components of the DC / DC converter, the bypass switch Km1 can be closed, causing the DC / DC converter to stop working, and the primary energy storage unit charges and discharges through the bypass switch Km1. At this time, the voltage of the primary energy storage unit is: V rack =V BAT .

[0075] When the primary energy storage unit needs voltage regulation, the bypass switch Km1 can be opened, allowing the DC / DC converter to operate and regulate the voltage V of the first capacitor Cm1. Cm1 At this time, the voltage of the first-stage energy storage unit is: V rack =V BAT +V Cm1 The voltage V of the first capacitor Cm1 is adjusted by a DC / DC converter. Cm1 It can enable the voltage of the primary energy storage unit to be adjusted within a certain range.

[0076] In some embodiments, when the energy storage system needs to discharge, the voltage of the corresponding first capacitor can be adjusted by the DC / DC converter in each energy storage component to make the discharge power of each first-level energy storage unit positively correlated with the battery state of charge (SOC); or, when the energy storage system needs to charge, the voltage of the corresponding first capacitor can be adjusted by the DC / DC converter in each energy storage component to make the charging power of each first-level energy storage unit negatively correlated with the battery SOC. Specifically, when the energy storage system needs to discharge, the discharge power of each first-level energy storage unit is positively correlated with the battery SOC; for example, the higher the battery SOC of a first-level energy storage unit, the greater the discharge power; and the lower the battery SOC of a first-level energy storage unit, the smaller the discharge power. When the energy storage system needs to charge, the charging power of each first-level energy storage unit is negatively correlated with the battery SOC; for example, the higher the battery SOC of a first-level energy storage unit, the smaller the charging power; and the lower the battery SOC of a first-level energy storage unit, the greater the charging power. The battery state of charge (SOC) can be abbreviated as SOC. Therefore, by adjusting the voltage of each primary energy storage unit, the power distribution among the primary energy storage units can be affected, thereby achieving energy balance among the primary energy storage units.

[0077] In the above embodiments, when the primary energy storage unit requires charging and discharging power regulation, if some or all of the energy storage components are equipped with bypass switches, at least some of the bypass switches can be disconnected to allow the corresponding DC / DC converter to operate. Conversely, when the primary energy storage unit does not require charging and discharging power regulation, if some or all of the energy storage components are equipped with bypass switches, at least some of the bypass switches can be closed to disable the corresponding DC / DC converter, thereby reducing the losses of the internal components of the DC / DC converter.

[0078] See Figure 6a and Figure 6b , Figure 6a This is one of the embodiments provided in this application. Figure 4 A schematic diagram of the discharge power adjustment of the energy storage system in the diagram. Figure 6b This is one of the embodiments provided in this application. Figure 4 A schematic diagram of the charging power adjustment of the energy storage system. Figure 6a middle,

[0079] P discharge_rack1 To P discharge_rackm This represents the discharge power of each primary energy storage unit. Figure 6b In the middle, P charge_rack1 To P charge_rackm The charging power for each primary energy storage unit.

[0080] For example, as shown in Figure 6, for an energy storage system, the total charging and discharging power is determined by the energy storage system itself. The charging and discharging power distribution among the parallel-connected primary energy storage units can be determined based on the characteristics of each primary energy storage unit, such as its battery voltage. When multiple primary energy storage units are connected in parallel, the voltage of each unit is the same. Since the voltage of a primary energy storage unit is the sum of the battery voltage and the voltage of the corresponding first capacitor, adjusting the voltage of the first capacitors C11 to Cm1 via a DC / DC converter can change the battery voltage within the primary energy storage unit, thereby controlling the charging and discharging power distribution among the primary energy storage units.

[0081] like Figure 6a As shown, in discharge mode, during the energy balancing process of each primary energy storage unit, the voltage of the first capacitor in a high-SOC primary energy storage unit can be controlled to be lower via a DC / DC converter, resulting in a higher battery voltage and greater discharge power for that primary energy storage unit. Conversely, the voltage of the first capacitor in a low-SOC primary energy storage unit can be controlled to be higher via a DC / DC converter, resulting in a lower battery voltage and less discharge power for that primary energy storage unit. After a certain period, the SOC values ​​of each primary energy storage unit tend to be consistent, entering the energy balancing requirement range.

[0082] like Figure 6b As shown, in charging mode, during the energy balancing process of each primary energy storage unit, the voltage of the first capacitor in a primary energy storage unit with a high SOC can be controlled to be higher via a DC / DC converter, resulting in a lower battery voltage and lower charging power for that primary energy storage unit. Conversely, the voltage of the first capacitor in a primary energy storage unit with a low SOC can be controlled to be lower via a DC / DC converter, resulting in a higher battery voltage and higher charging power for that primary energy storage unit. After a certain period of time, the SOC values ​​of each primary energy storage unit tend to be consistent, entering the energy balancing requirement range.

[0083] See Figure 7 , Figure 7 This is a structural block diagram of another energy storage system provided in an embodiment of this application. Figure 7In this configuration, m primary energy storage units are connected in parallel. K1 to Km are the first switches, used to disconnect a faulty primary energy storage unit. BAT11 to BAT1n...BATm1 to BATmn are secondary energy storage units, C11 to C1n...Cm1 to Cmn are the first capacitors, and K11 to K1n...Km1 to Kmn are bypass switches. Specifically, secondary energy storage unit BAT11, the DC / DC converter, the first capacitor C11, and the bypass switch K11 form one energy storage component; secondary energy storage unit BAT12, the DC / DC converter, the first capacitor C12, and the bypass switch K12 form another energy storage component; and so on. Secondary energy storage unit BAT1n, the DC / DC converter, the first capacitor C1n, and the bypass switch K1n form another energy storage component. These n energy storage components and the first switch K1 form one primary energy storage unit. Similarly, the secondary energy storage unit BATm1, the DC / DC converter, the first capacitor Cm1, and the bypass switch Km1 are used to form an energy storage component; the secondary energy storage unit BATm2, the DC / DC converter, the first capacitor Cm2, and the bypass switch Km2 are used to form an energy storage component; and so on, the secondary energy storage unit BATmn, the DC / DC converter, the first capacitor Cmn, and the bypass switch Kmn are used to form an energy storage component; these n energy storage components and the first switch Km are used to form a primary energy storage unit.

[0084] like Figure 7 As shown, in some embodiments, the number of energy storage components in the primary energy storage unit can be greater than one, and the number of secondary energy storage units in the energy storage components can be one. Figure 4 Compared to energy storage systems in China, Figure 7 Each DC / DC converter in the system can form an energy storage component with a secondary energy storage unit, a first capacitor, and a bypass switch. In some embodiments, the secondary energy storage unit can be a battery pack. In this case, the DC / DC converter corresponds to the battery pack, and can be regarded as integrating the DC / DC converter into the energy storage unit at the battery pack level. This results in a high degree of modularity and enables pack-level energy balance control.

[0085] In some embodiments, when voltage regulation of the energy storage component is required, the voltage of the corresponding first capacitor can be adjusted by the DC / DC converter in the energy storage component to regulate the voltage of the energy storage component. Thus, the voltage of the first capacitor in the energy storage component can be adjusted by the DC / DC converter, achieving voltage regulation of the energy storage component. Based on this, by regulating the voltage of each energy storage component, the voltage regulation of the first-level energy storage unit can be achieved.

[0086] See Figure 8 , Figure 8 This is one of the embodiments provided in this application. Figure 7A schematic diagram of voltage regulation for the energy storage components. Figure 8 In the middle, V BATm1 V is the battery voltage of the secondary energy storage unit BATm1. Cm1 V is the voltage across the first capacitor Cm1. BAT_PACK This represents the voltage of the energy storage component.

[0087] For example, suppose the energy storage module is equipped with a bypass switch. When the energy storage module does not require voltage regulation, to reduce the losses of the DC / DC converter, the bypass switch Km1 can be closed, causing the DC / DC converter to stop working and charging and discharging to occur through the bypass switch Km1. At this time, the voltage of the energy storage module is: V BAT_PACK =V BATm1 .

[0088] When the energy storage component requires voltage regulation, the bypass switch Km1 can be opened, allowing the DC / DC converter to operate. The DC / DC converter can then regulate the voltage V of the first capacitor Cm1. Cm1 At this time, the voltage of the energy storage component is: V BAT_PACK =V BATm1 +V Cm1 By adjusting the voltage V of the first capacitor Cm1 Cm1 This can achieve the voltage V of the energy storage component. BAT_PACK It is adjustable within a certain range.

[0089] In some embodiments, when the energy storage system needs to discharge, in the first-level energy storage unit, the corresponding first current can be adjusted by the DC / DC converter in each energy storage component to make the discharge power of each energy storage component positively correlated with the battery state of charge (SOC); or, when the energy storage system needs to charge, in the first-level energy storage unit, the corresponding first current can be adjusted by the DC / DC converter in each energy storage component to make the charging power of each energy storage component negatively correlated with the battery SOC. Here, the first current refers to the current flowing through the DC / DC converter. When the energy storage system needs to discharge, the discharge power of each energy storage component is positively correlated with the battery SOC; for example, the higher the battery SOC of the energy storage component, the greater the discharge power; the lower the battery SOC of the energy storage component, the smaller the discharge power. When the energy storage system needs to charge, the charging power of each energy storage component is negatively correlated with the battery SOC; for example, the higher the battery SOC of the energy storage component, the smaller the charging power; the lower the battery SOC of the energy storage component, the greater the charging power. Therefore, the magnitude of the corresponding first current can be adjusted by the DC / DC converter, thereby changing the power processed by the DC / DC converter, and thus changing the output power of each energy storage component (e.g., in the form of charging and discharging power), achieving energy balance among the energy storage components in the primary energy storage unit.

[0090] See Figure 9a and Figure 9b , Figure 9a This is one of the embodiments provided in this application. Figure 7 A schematic diagram of the current direction of the energy storage component in discharge mode. Figure 9b This is one of the embodiments provided in this application. Figure 7 A schematic diagram of the current direction of the energy storage component in charging mode. Figure 9a middle, I discharge I is the discharge current of the energy storage module. main Main current, I DC / DC This is the first current flowing through the DC / DC converter. Figure 9b middle, I charge I is the charging current of the energy storage component. main Main current, I DC / DC This is the first current flowing through the DC / DC converter.

[0091] like Figure 9a and Figure 9b As shown, the current of the energy storage component (including the discharge current I) discharge and charging current I charge It can be divided into two parts, I main and I DC / DC Among them, the main current I main For example, the power distribution of the system and the external characteristics of the primary energy storage unit can be determined, while the secondary energy storage unit is difficult to control directly. The first current I can be adjusted through a DC / DC converter. DC / DC Size.

[0092] like Figure 9a As shown, in discharge mode, the discharge power of the energy storage module can be expressed as:

[0093] P discharge =I main ×V BAT +I DC / DC ×V BAT During the energy balancing process among series-connected energy storage components, I main The first current I in each energy storage component remains unchanged; it can be adjusted via a DC / DC converter. DC / DC The magnitude of the discharge current I of each energy storage component is adjusted accordingly. discharge This allows for the control of the discharge power of each energy storage component connected in series in the primary energy storage unit. For example, the discharge power of energy storage components with high SOC can be increased, while the discharge power of energy storage components with low SOC can be decreased. After a certain period of time, the SOC values ​​of each energy storage component tend to be consistent, entering the energy balance requirement range.

[0094] like Figure 9bAs shown, in charging mode, the charging power of the energy storage component can be expressed as:

[0095] P charge =I main ×V BAT +I DC / DC ×V BAT During the energy balancing process among series-connected energy storage components, I main The first current I in each energy storage component remains unchanged; it can be adjusted via a DC / DC converter. DC / DC The size of the current I is adjusted to regulate the charging current I of each energy storage component. charge This allows for control over the charging power of each energy storage component connected in series within the primary energy storage unit. For example, the charging power of energy storage components with high SOC can be reduced, while the charging power of energy storage components with low SOC can be increased. After a certain period of time, the SOC values ​​of each energy storage component tend to be consistent, entering the energy balance requirement range.

[0096] In some embodiments, when the energy storage system needs to discharge, the voltage of the corresponding first capacitor in each primary energy storage unit can be adjusted by the DC / DC converter in each energy storage component, so that the discharge power of each primary energy storage unit is positively correlated with the battery's state of charge; or, when the energy storage system needs to charge, the voltage of the corresponding first capacitor in each primary energy storage unit can be adjusted by the DC / DC converter in each energy storage component, so that the charging power of each primary energy storage unit is negatively correlated with the battery's state of charge. Thus, the voltage of the corresponding first capacitor can be adjusted by the DC / DC converter. Since the voltage of a primary energy storage unit is the sum of the battery voltage and the voltages of each first capacitor, adjusting the voltage of each first capacitor can adjust the battery voltage of the primary energy storage unit; adjusting the battery voltage of each primary energy storage unit can affect the power distribution among the primary energy storage units, achieving energy balance. Figure 4 The difference between the two solutions is that, Figure 7 The voltage of each energy storage component can be adjusted individually.

[0097] See Figure 10a and Figure 10b , Figure 10a This is one of the embodiments provided in this application. Figure 7 A schematic diagram of the discharge power adjustment of the energy storage system in the diagram. Figure 10b This is one of the embodiments provided in this application. Figure 7 A schematic diagram of the charging power adjustment of the energy storage system. Figure 10a In the middle, P discharge_rack1 To P discharge_rackm V represents the discharge power of each primary energy storage unit. rack1 V is the voltage of the first-level energy storage unit. PACK11 To V PACK1nV represents the voltage of each energy storage component. C11 V is the voltage across the first capacitor C11. BAT11 This refers to the voltage of the secondary energy storage unit BAT11. Figure 10b In the middle, P charge_rack1 To P charge_rackm The charging power for each primary energy storage unit.

[0098] like Figure 10a As shown, during the energy balancing process among the primary energy storage units, the voltage of the first capacitor in each primary energy storage unit can be controlled by the DC / DC converter. This results in the primary energy storage unit with a high SOC having a higher battery voltage and greater discharge power, while the primary energy storage unit with a low SOC has a lower battery voltage and less discharge power. After a certain period of time, the SOC values ​​of each primary energy storage unit tend to be consistent and enter the energy balancing requirement range.

[0099] like Figure 10b As shown, during the energy balancing process among the primary energy storage units, the voltage of the first capacitor in each primary energy storage unit can be controlled by the DC / DC converter. This results in the battery voltage of the primary energy storage unit with a high SOC being lower and the charging power being lower, while the battery voltage of the primary energy storage unit with a low SOC is higher and the charging power is greater. After a certain period of time, the SOC values ​​of each primary energy storage unit tend to be consistent and enter the energy balancing requirement range.

[0100] See Figure 11 , Figure 11 This is a flowchart illustrating a control method for an energy storage system provided in an embodiment of this application.

[0101] This application also provides a control method for an energy storage system, applicable to any of the above-mentioned energy storage systems. The method may include one or more of the following steps (i.e., steps S101 to S103).

[0102] Step S101: When the voltage of the primary energy storage unit needs to be regulated, the voltage of the corresponding first capacitor is regulated by at least part of the DC / DC converter in the primary energy storage unit to regulate the voltage of the primary energy storage unit.

[0103] Step S102: When energy balancing is required for each primary energy storage unit, the voltage of the corresponding first capacitor is adjusted by at least part of the DC / DC converter in each primary energy storage unit, so that the discharge power of each primary energy storage unit in the discharge state is positively correlated with the battery state of charge, or the charging power of each primary energy storage unit in the charging state is negatively correlated with the battery state of charge.

[0104] Step S103: In the first-level energy storage unit, when energy balancing is required for each energy storage component, the corresponding first current is adjusted by the DC / DC converter in each energy storage component so that the discharge power of each energy storage component in the discharge state is positively correlated with the battery state of charge, or so that the charging power of each energy storage component in the charging state is negatively correlated with the battery state of charge.

[0105] See Figure 12 , Figure 12 This is a structural block diagram of a controller provided in an embodiment of this application.

[0106] This application also provides a controller, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement any of the methods described above.

[0107] The controller may include a memory 110, a processor 120, and a communication interface 130. The memory 110, the processor 120, and the communication interface 130 are connected through internal connection paths.

[0108] The memory 110 is used to store computer programs, which in some implementations may include code for implementing the methods of the embodiments of this application.

[0109] The processor 120 executes the computer program stored in the memory 110 to control the communication interface 130 to receive input data and information, and output operation results and other data. In some implementations, when the solutions of the embodiments of this application are implemented by software or firmware, the computer program used to implement the solutions of the embodiments of this application can be stored in the processor 120 and executed by the processor 120.

[0110] The memory 110 may be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory may be random access memory (RAM). It should be noted that the memory 110 described herein is intended to include, but is not limited to, any memory of these and other suitable types. As an example, the memory 110 includes random access memory (RAM), cache memory, and read-only memory (ROM). The memory 110 stores a computer program that can be executed by processor 120, causing processor 120 to implement the steps of any of the methods described above.

[0111] The processor 120 can be a central processing unit (CPU), or it can be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor, or the processor 120 can be any conventional processor.

[0112] In implementation, each step of the above method can be completed by the integrated logic circuitry of the hardware in the processor 120 or by instructions in software form. The method disclosed in the embodiments of this application can be directly implemented by the hardware processor, or by a combination of hardware and software modules in the processor 120. The software modules can be located in mature storage media in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. This storage medium is located in the memory 110, and the processor 120 reads the information in the memory 110 and, in conjunction with its hardware, completes the steps of the above method. To avoid repetition, detailed descriptions are not provided here.

[0113] In some implementations, the controller may include not only the hardware units described above, but also software modules, such as an operating system, a Basic Input Output System (BIOS), and application software.

[0114] An operating system is used to manage one or more of the hardware and software resources of a controller; it is the kernel and foundation of the controller. The operating system handles fundamental tasks such as managing and configuring memory, determining the priority of system resource allocation and demand, controlling input and output devices, operating the network, and managing the file system. To facilitate user operation, most operating systems provide a user interface for interaction with the system.

[0115] The BIOS is used to perform hardware initialization during the power-on boot phase and to provide runtime services for the operating system and applications. In some implementations, the BIOS can also monitor and display processor temperature and execute temperature protection strategies.

[0116] Application software, also known as an application program, can be understood as software written for a specific user application purpose, and is one of the main categories of computer software. For example, application software can be a program used to achieve purposes such as power control and temperature management.

[0117] This application embodiment also provides a battery cluster, which includes multiple battery packs, a DC / DC converter, and a first capacitor. The multiple battery packs and the first capacitor are connected in series. The positive and negative terminals of the first end of the DC / DC converter are respectively connected to the two ends of the multiple battery packs, and the positive and negative terminals of the second end of the DC / DC converter are respectively connected to the two ends of the first capacitor.

[0118] This application embodiment also provides an energy storage component, which includes a battery pack, a DC / DC converter, and a first capacitor. The battery pack and the first capacitor are connected in series. The positive and negative terminals of the first end of the DC / DC converter are respectively connected to the two ends of the battery pack, and the positive and negative terminals of the second end of the DC / DC converter are respectively connected to the two ends of the first capacitor.

[0119] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements any of the above methods.

[0120] This application also provides a computer program product, which includes a computer program that, when executed by a processor, implements any of the methods described above.

[0121] The computer program product may be in the form of a portable compact disc read-only memory (CD-ROM) and include program code, and may run on a terminal device, such as a personal computer. However, the computer program product of this application is not limited thereto, and the computer program product may be in any combination of one or more computer-readable media.

[0122] This application also provides a chip for performing any of the above methods.

[0123] It is understood that the specific examples in this application are only intended to help those skilled in the art better understand the implementation of this application, and are not intended to limit the scope of protection of this application.

[0124] It is understood that in the various embodiments of this application, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of this application.

[0125] It is understood that the various implementation methods described in this application can be implemented individually or in combination, and this application does not limit them.

[0126] Unless otherwise stated, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The term "one or more" as used in this application includes any and all combinations of one or more of the associated listed items. The singular forms "a," "the," and "the" as used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0127] Those skilled in the art will recognize that the units and algorithm steps of the various examples 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 implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art 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.

[0128] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the embodiments described above can be referred to the corresponding processes in other embodiments, and will not be repeated here.

[0129] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0130] The units described as separate components may or may not be physically separate. 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 the units can be selected to achieve the purpose of the technical solution in this application, depending on actual needs.

[0131] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0132] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, essentially, or the part that contributes to the prior art, or 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 to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0133] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An energy storage system, characterized in that, The energy storage system includes at least one primary energy storage unit, and the primary energy storage unit includes at least one energy storage component. The energy storage component includes at least one secondary energy storage unit, a DC / DC converter, and a first capacitor. The at least one secondary energy storage unit and the first capacitor are connected in series. The positive and negative terminals of the first end of the DC / DC converter are respectively connected to the two ends of the at least one secondary energy storage unit, and the positive and negative terminals of the second end of the DC / DC converter are respectively connected to the two ends of the first capacitor.

2. The energy storage system according to claim 1, characterized in that, When the number of primary energy storage units in the energy storage system is greater than one, multiple primary energy storage units are connected in parallel; or, When the number of energy storage components in the primary energy storage unit is greater than one, multiple energy storage components are connected in series; or... When the number of secondary energy storage units in the energy storage component is greater than 1, multiple secondary energy storage units are connected in series.

3. The energy storage system according to claim 1, characterized in that, In the event of a high-voltage ride-through in the energy storage system, the voltage of the first capacitor is adjusted by at least a portion of the DC / DC converter in the first-level energy storage unit to regulate the voltage of the first-level energy storage unit.

4. The energy storage system according to claim 1, characterized in that, At least some of the energy storage components also include a bypass switch, the two ends of which are respectively connected to the positive and negative terminals of the second terminal of the DC / DC converter; The bypass switch is closed to disable the corresponding DC / DC converter; or the bypass switch is open to enable the corresponding DC / DC converter to operate.

5. The energy storage system according to claim 4, characterized in that, In the event of a high-voltage ride-through in the energy storage system, at least some bypass switches are disconnected to allow the corresponding DC / DC converter to operate.

6. The energy storage system according to claim 4, characterized in that, In the absence of a fault in the energy storage system, at least some bypass switches are closed to disable the corresponding DC / DC converters.

7. The energy storage system according to claim 1, characterized in that, The number of energy storage components in the primary energy storage unit is 1, and the number of secondary energy storage units in the energy storage components is greater than 1.

8. The energy storage system according to claim 7, characterized in that, When the voltage of the primary energy storage unit needs to be regulated, the voltage of the corresponding first capacitor is adjusted by a DC / DC converter to regulate the voltage of the primary energy storage unit.

9. The energy storage system according to claim 7, characterized in that, When the energy storage system needs to discharge, the voltage of the corresponding first capacitor is adjusted by the DC / DC converter in each energy storage component so that the discharge power of each primary energy storage unit is positively correlated with the battery's state of charge; or, When the energy storage system needs to be charged, the voltage of the corresponding first capacitor is adjusted by the DC / DC converter in each energy storage component so that the charging power of each first-level energy storage unit is negatively correlated with the battery state of charge.

10. The energy storage system according to claim 1, characterized in that, The number of energy storage components in the primary energy storage unit is greater than 1, and the number of secondary energy storage units in the energy storage components is 1.

11. The energy storage system according to claim 10, characterized in that, When the energy storage component requires voltage regulation, the voltage of the corresponding first capacitor is adjusted by the DC / DC converter in the energy storage component to regulate the voltage of the energy storage component.

12. The energy storage system according to claim 10, characterized in that, When the energy storage system needs to discharge, in the first-level energy storage unit, the corresponding first current is adjusted by the DC / DC converter in each energy storage component so that the discharge power of each energy storage component is positively correlated with the battery's state of charge; or, When the energy storage system needs to be charged, in the first-level energy storage unit, the corresponding first current is adjusted by the DC / DC converter in each energy storage component so that the charging power of each energy storage component is negatively correlated with the battery state of charge.

13. The energy storage system according to claim 10, characterized in that, When the energy storage system needs to discharge, in each primary energy storage unit, the voltage of the corresponding first capacitor is adjusted by the DC / DC converter in each energy storage component so that the discharge power of each primary energy storage unit is positively correlated with the battery's state of charge; or, When the energy storage system needs to be charged, in each primary energy storage unit, the voltage of the corresponding first capacitor is adjusted by the DC / DC converter in each energy storage component so that the charging power of each primary energy storage unit is negatively correlated with the battery state of charge.

14. The energy storage system according to any one of claims 1 to 13, characterized in that, The DC / DC converter includes one or more of non-isolated and isolated topologies.

15. The energy storage system according to any one of claims 1 to 13, characterized in that, The primary energy storage unit also includes a first switch, which is connected in series with the at least one energy storage component.

16. The energy storage system according to any one of claims 1 to 13, characterized in that, The primary energy storage unit is a battery cluster, and the secondary energy storage unit is a battery pack.

17. A control method for an energy storage system, characterized in that, The method, applied to the energy storage system according to any one of claims 1 to 16, comprises: When voltage regulation is required in the primary energy storage unit, the voltage of the corresponding first capacitor is adjusted by at least a portion of the DC / DC converter in the primary energy storage unit to regulate the voltage of the primary energy storage unit; or, When energy balancing is required among the primary energy storage units, the voltage of the corresponding first capacitor is adjusted by at least a portion of the DC / DC converters in each primary energy storage unit, so that the discharge power of each primary energy storage unit in the discharge state is positively correlated with the battery's state of charge, or, so that the charging power of each primary energy storage unit in the charging state is negatively correlated with the battery's state of charge; or... In the first-level energy storage unit, when energy balancing is required among the energy storage components, the corresponding first current is adjusted by the DC / DC converter in each energy storage component so that the discharge power of each energy storage component in the discharge state is positively correlated with the battery state of charge, or so that the charging power of each energy storage component in the charging state is negatively correlated with the battery state of charge.

18. A controller, characterized in that, The controller includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the method of claim 17.

19. A battery cluster, characterized in that, The battery cluster includes multiple battery packs, a DC / DC converter, and a first capacitor. The multiple battery packs and the first capacitor are connected in series. The positive and negative terminals of the first end of the DC / DC converter are respectively connected to the two ends of the multiple battery packs, and the positive and negative terminals of the second end of the DC / DC converter are respectively connected to the two ends of the first capacitor.

20. An energy storage component, characterized in that, The energy storage component includes a battery pack, a DC / DC converter, and a first capacitor. The battery pack and the first capacitor are connected in series. The positive and negative terminals of the first end of the DC / DC converter are respectively connected to the two ends of the battery pack, and the positive and negative terminals of the second end of the DC / DC converter are respectively connected to the two ends of the first capacitor.

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