Energy storage system and equalization method

Abstract

The invention discloses an energy storage system and an equalization method. The energy storage system comprises multiple battery clusters, the multiple battery clusters are connected in parallel to form a first node and a second node, each battery cluster comprises at least one battery pack and an equalization circuit, each equalization circuit comprises a first switch unit and a first adjustable resistor, and one end of each first adjustable resistor is electrically connected with the first end of the corresponding first switch unit and one end of the corresponding battery pack; the other end of the first adjustable resistor is electrically connected with the second end of the first switch unit, and the third end of the first switch unit is electrically connected with the second node; or one end of the first adjustable resistor is electrically connected with the second end of the first switch unit, the other end of the first adjustable resistor is electrically connected with the first end of the first switch unit and the second node respectively, and the third end of the first switch unit is electrically connected with one end of the battery pack, so that the first adjustable resistor can be adopted to carry out equalization adjustment on the battery cluster. Therefore, the consistency among the battery clusters in the energy storage system is higher.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to an energy storage system and a balancing method. Background Art

[0002] The driving range and battery life of electric vehicles are important factors restricting the development of electric vehicles. The consistency problem between the batteries in the energy storage system is an important factor affecting the driving range and battery life.

[0003] In related technologies, since the voltage internal resistance of each battery cell in the energy storage system varies, the differences become more significant after the battery cells are integrated into a battery cluster. Therefore, how to balance the battery clusters of the energy storage system to ensure consistency between battery clusters is a technical problem that needs to be solved urgently. Summary of the Invention

[0004] In response to the deficiencies of the prior art, the present application provides an energy storage system and a balancing method, which aim to solve the technical problem of poor consistency between battery clusters in the energy storage system in the prior art.

[0005] To solve the above problems, in a first aspect, the present application provides an energy storage system comprising a plurality of battery clusters connected in parallel to form a first node and a second node, wherein at least one battery cluster comprises: at least one battery pack; A balancing circuit includes a first switch unit and a first adjustable resistor, the first switch unit includes a first end, a second end, and a third end, one end of the first adjustable resistor is electrically connected to the first end of the first switch unit and one end of the battery pack, the other end of the first adjustable resistor is electrically connected to the second end of the first switch unit, and the third end of the first switch unit is electrically connected to the second node; or, one end of the first adjustable resistor is electrically connected to the second end of the first switch unit, the other end of the first adjustable resistor is electrically connected to the first end of the first switch unit and the second node, and the third end of the first switch unit is electrically connected to one end of the battery pack; When the battery cluster needs to be balanced, the first switch unit is configured to be conductive between the second terminal and the third terminal.

[0006] Furthermore, in the energy storage system provided in the present application, when the battery cluster does not need to be balanced, the first switch unit is configured to be conductive between the first end and the third end, and disconnected between the second end and the third end.

[0007] Furthermore, in the energy storage system provided in the present application, the first switch unit includes a first balancing switch and a second balancing switch; One end of the first balancing switch is electrically connected to one end of the first adjustable resistor and one end of the battery pack, the other end of the first balancing switch is electrically connected to one end of the second balancing switch and the second node, and the other end of the second balancing switch is electrically connected to the other end of the first adjustable resistor; When the battery cluster needs to be balanced, the first balancing switch is configured to be disconnected at both ends, and the second balancing switch is configured to be connected at both ends.

[0008] Furthermore, in the energy storage system provided in the present application, the first switch unit includes a single-pole double-throw switch; In which, the first end of the single-pole double-throw switch is electrically connected to one end of the battery pack and one end of the first adjustable resistor, the second end of the single-pole double-throw switch is electrically connected to the other end of the first adjustable resistor, and the third end of the single-pole double-throw switch is electrically connected to the second node; or, the first end of the single-pole double-throw switch is electrically connected to the other end of the first adjustable resistor and the second node, the second end of the single-pole double-throw switch is electrically connected to one end of the first adjustable resistor, and the third end of the single-pole double-throw switch is electrically connected to one end of the battery pack.

[0009] Furthermore, in the energy storage system provided in the present application, the balancing circuit further includes a second adjustable resistor; The first switch unit further includes a fourth terminal, one end of the second adjustable resistor is electrically connected to the first terminal of the first switch unit and one end of the battery pack, and the other end of the second adjustable resistor is electrically connected to the fourth terminal of the first switch unit; or, one end of the second adjustable resistor is electrically connected to the fourth terminal of the first switch unit, and the other end of the second adjustable resistor is electrically connected to the first terminal of the first switch unit and the second node, respectively; When the battery cluster needs to be balanced, the first switch unit is configured to be conductive between the third terminal and the fourth terminal.

[0010] Furthermore, in the energy storage system provided in the present application, the energy storage system further includes an energy storage converter, which includes: A first pre-charging circuit, wherein a first end of the first pre-charging circuit is electrically connected to the first node, a second end of the pre-charging circuit is electrically connected to the second node, and the first pre-charging circuit is configured to perform power-on protection on the DC side of the energy storage converter; an inverter circuit, wherein a first end of the inverter circuit is electrically connected to the third end of the first pre-charging circuit, a second end of the inverter circuit is electrically connected to the fourth end of the first pre-charging circuit, and the inverter circuit is configured to convert between alternating current and direct current; A rectifier circuit, wherein the first end of the rectifier circuit is electrically connected to the third end of the inverter circuit, the second end of the rectifier circuit is electrically connected to the fourth end of the inverter circuit, the third end of the rectifier circuit is electrically connected to the fifth end of the inverter circuit, the fourth end, the fifth end and the sixth end of the rectifier circuit are configured to be connected to the power grid, and the rectifier circuit is configured to perform rectification and filtering.

[0011] Furthermore, in the energy storage system provided in the present application, the first pre-charging circuit includes a first pre-charging switch, a second pre-charging switch, a third pre-charging switch, and a fourth pre-charging switch; Among them, one end of the first pre-charge switch is electrically connected to the first node, the other end of the first pre-charge switch is electrically connected to one end of the second pre-charge switch, the other end of the second pre-charge switch is electrically connected to the first end of the inverter circuit, one end of the third pre-charge switch is electrically connected to the second node, the other end of the third pre-charge switch is electrically connected to one end of the fourth pre-charge switch, and the other end of the fourth pre-charge switch is electrically connected to the second end of the inverter circuit.

[0012] Furthermore, in the energy storage system provided in the present application, the first pre-charging circuit further includes a fifth pre-charging switch and a pre-charging resistor; Among them, one end of the fifth pre-charge switch is electrically connected to the other end of the third pre-charge switch and one end of the fourth pre-charge switch, the other end of the fifth pre-charge switch is electrically connected to one end of the pre-charge resistor, and one end of the pre-charge resistor is electrically connected to the other end of the fourth pre-charge switch.

[0013] Furthermore, in the energy storage system provided in the present application, the energy storage converter further includes a second pre-charging circuit; Among them, the first end of the second pre-charging circuit is electrically connected to the third end of the rectifier circuit, the second end of the second pre-charging circuit is electrically connected to the fourth end of the rectifier circuit, the third end of the second pre-charging circuit is electrically connected to the fifth end of the rectifier circuit, the fourth end, the fifth end and the sixth end of the second pre-charging circuit are configured to be connected to the power grid, and the second pre-charging circuit is configured to power on protection of the AC side of the energy storage converter.

[0014] Furthermore, in the energy storage system provided in the present application, the battery cluster further includes a third pre-charging circuit; Among them, the first end of the third pre-charging circuit is electrically connected to one end of the battery pack, the second end of the third pre-charging circuit is electrically connected to the other end of the battery pack, the third end of the third pre-charging circuit is electrically connected to the first node, and the fourth end of the third pre-charging circuit is electrically connected to the balancing circuit. The third pre-charging circuit is configured to perform power-on protection on the battery pack.

[0015] Furthermore, in the energy storage system provided in the present application, the third pre-charging circuit includes a sixth pre-charging switch, a seventh pre-charging switch, and an eighth pre-charging switch; Among them, one end of the sixth pre-charge switch and one end of the seventh pre-charge switch are both electrically connected to one end of the battery pack, the other end of the sixth pre-charge switch and the other end of the seventh pre-charge switch are both electrically connected to the balancing circuit, one end of the eighth pre-charge switch is electrically connected to the other end of the battery pack, and the other end of the eighth pre-charge switch is electrically connected to the first node.

[0016] Furthermore, in the energy storage system provided in the present application, the energy storage system further includes an isolating switch; The first end of the isolation switch is electrically connected to the first node, the second end of the isolation switch is electrically connected to the second node, the third end and the fourth end of the isolation switch are respectively configured to be electrically connected to the target device, and the isolation switch is configured to open or close the circuit of the battery cluster.

[0017] Furthermore, in the energy storage system provided in the present application, the energy storage system also includes a battery array management unit, which is configured to control the on-off between the second end and the third end of the first switch unit and adjust the resistance value of the first adjustable resistor.

[0018] Furthermore, in the energy storage system provided in the present application, the battery array management unit further includes at least one battery cluster management unit, and the battery cluster management unit includes at least one battery pack management unit; Among them, the battery pack management unit is configured to collect the voltage signals of the single cells in the battery pack, the battery cluster management unit is configured to process the voltage signals, and the battery array management unit is configured to control the on and off between the second end and the third end of the first switch unit and adjust the resistance value of the first adjustable resistor based on the processing information of the voltage signal uploaded by the battery cluster management unit.

[0019] In a second aspect, the present application further provides a balancing method, which is applied to the energy storage system of the first aspect, and the balancing method includes: Obtaining a first voltage difference between two battery clusters; wherein the two battery clusters are a first battery cluster and a second battery cluster, and the first battery cluster and the second battery cluster are connected in parallel; If the first voltage difference is greater than a preset first voltage and less than a preset second voltage, adjusting the resistance value of the first adjustable resistor in the first battery cluster; The second terminal and the third terminal of the first switch unit in the first battery cluster are controlled to be conductive; wherein the cluster terminal voltage of the first battery cluster is greater than the cluster terminal voltage of the second battery cluster.

[0020] Furthermore, in the balancing method provided in the present application, before obtaining the first voltage difference between the two battery clusters, the method further includes: obtaining a second voltage difference between the two battery clusters; If the second voltage difference is less than or equal to a preset third voltage, controlling the seventh pre-charge switch and the eighth pre-charge switch in the first battery cluster to be closed; If the second voltage difference is greater than the third voltage, the sixth pre-charge switch and the eighth pre-charge switch in the first battery cluster are controlled to be closed, and after being closed for a preset first time, the sixth pre-charge switch is controlled to be opened and the seventh pre-charge switch is controlled to be closed.

[0021] Furthermore, in the balancing method provided in this application, the balancing method further includes: After the second terminal and the third terminal of the first switch unit in the first battery cluster are conducted for a preset second time, obtaining a third voltage difference between the first battery cluster and the second battery cluster; If the third voltage difference is less than or equal to a preset fourth voltage, controlling the first terminal and the third terminal of the first switch unit in the first battery cluster to be conductive, and the second terminal and the third terminal to be disconnected; If the third voltage difference is greater than the fourth voltage, fault information of the first battery cluster is generated.

[0022] The energy storage system provided in the present application includes multiple battery clusters, which are connected in parallel to form a first node and a second node. The battery cluster includes at least one battery pack and a balancing circuit. The balancing circuit includes a first switch unit and a first adjustable resistor. One end of the first adjustable resistor is electrically connected to the first end of the first switch unit and one end of the battery pack, the other end of the first adjustable resistor is electrically connected to the second end of the first switch unit, and the third end of the first switch unit is electrically connected to the second node; or one end of the first adjustable resistor is electrically connected to the second end of the first switch unit, the other end of the first adjustable resistor is electrically connected to the first end of the first switch unit and the second node, and the third end of the first switch unit is electrically connected to one end of the battery pack. Therefore, when the battery cluster needs to be balanced, it is only necessary to connect the second end and the third end of the first switch unit, and then the first adjustable resistor can be used to balance the battery cluster, which can make the consistency between the battery clusters in the energy storage system higher, improve the balancing efficiency of the battery cluster, and reduce the power loss during the balancing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] 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 description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0024] Figure 1 A first schematic diagram of an energy storage system provided in an embodiment of the present application; Figure 2 A second schematic diagram of the energy storage system provided in an embodiment of the present application; Figure 3 A first schematic diagram of the connection between a battery cluster and a battery array management unit provided in an embodiment of the present application; Figure 4 A second schematic diagram of the connection between the battery cluster and the battery array management unit provided in an embodiment of the present application; Figure 5 A third schematic diagram of the connection between the battery cluster and the battery array management unit provided in an embodiment of the present application; Figure 6A third schematic diagram of the energy storage system provided in an embodiment of the present application; Figure 7 A fourth schematic diagram of an energy storage system provided in an embodiment of the present application; Figure 8 A schematic diagram of the connection between the energy storage converter and the battery array management unit provided in an embodiment of the present application; Figure 9 A schematic diagram of a first flow chart of the balancing method provided in an embodiment of the present application; Figure 10 A second flow chart of the balancing method provided in an embodiment of the present application; Figure 11 This is a schematic diagram of the third flow chart of the balancing method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0026] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0027] It should also be understood that the terms used in this specification are for the purpose of describing specific embodiments only and are not intended to limit the present application. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0028] It should be further understood that the term "and / or" used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0029] In related technologies, one end of a battery cluster is typically equipped with two switches and a fixed resistor. The resistor is connected in series with one of the switches and then in parallel with the other. To balance the voltage of the battery cluster, one switch is closed and the other is open, allowing passive balancing to be performed using the resistor. However, even after balancing the battery cluster using this method, the fixed resistor means that the voltage consistency between the battery cluster and other battery clusters remains poor.

[0030] In order to solve the technical problem that the voltage consistency between the battery clusters 10 is still poor due to the above-mentioned passive balancing, the present application provides an energy storage system and a balancing method.

[0031] See also Figure 1 and Figure 2 , Figure 1 A schematic block diagram of an energy storage system provided in an embodiment of the present application; Figure 2 This is another schematic block diagram of the energy storage system provided in the embodiment of the present application. Figure 1 and Figure 2 As shown, an energy storage system includes a plurality of battery clusters 10, wherein the plurality of battery clusters 10 are connected in parallel to form a first node A and a first node B, and at least one battery cluster 10 includes: at least one battery pack 110; The balancing circuit 120 includes a first switch unit 121 and a first adjustable resistor 122. The first switch unit 121 includes a first end, a second end, and a third end. One end of the first adjustable resistor 122 is electrically connected to the first end of the first switch unit 121 and one end of the battery pack 110, respectively. The other end of the first adjustable resistor 122 is electrically connected to the second end of the first switch unit 121. The third end of the first switch unit 121 is electrically connected to the first node B. Alternatively, one end of the first adjustable resistor 122 is electrically connected to the second end of the first switch unit 121, the other end of the first adjustable resistor 122 is electrically connected to the first end of the first switch unit 121 and the first node B, respectively. The third end of the first switch unit 121 is electrically connected to one end of the battery pack 110. When the battery cluster 10 needs to be balanced, the first switch unit 121 is configured to be conductive between the second terminal and the third terminal.

[0032] Specifically, whether balancing is required among the battery clusters 10 can be determined by obtaining the cluster terminal voltage of each battery cluster 10 and then obtaining the voltage difference between the cluster terminal voltages. If balancing is determined to be necessary, the resistance value of the first adjustable resistor 122 can be adjusted, and the second and third terminals of the first switch unit 121 can be switched on to achieve balancing of the battery clusters 10, thereby ensuring consistency of the cluster terminal voltages among the battery clusters 10.

[0033] It can be understood that when the battery cluster 10 needs to be balanced, the second terminal and the third terminal of the first switch unit 121 in the battery cluster 10 are connected, and the first terminal and the third terminal of the first switch unit 121 are disconnected.

[0034] In addition, the connection between the first switch unit 121 and the first adjustable resistor 122 in the battery cluster 10 has at least the following connection modes: Figure 1 and Figure 2 There are two ways shown. Figure 1 As shown in FIG, the first switch unit 121 is provided between the first adjustable resistor 122 and one end of the battery pack 110. Figure 2 As shown, the first switch unit 121 is provided between the first adjustable resistor 122 and the first node B.

[0035] In this embodiment, since the resistance value of the first adjustable resistor 122 is adjustable, it provides greater flexibility during the balancing process of the battery clusters 10, ensuring greater voltage consistency among the battery clusters 10 after balancing. The amount of resistance adjustment of the first adjustable resistor 122 can be determined based on the voltage difference, thereby ensuring that after balancing, the voltage difference between the battery cluster 10 and other battery clusters 10 falls within a preset voltage range.

[0036] The energy storage system provided in the present application includes a plurality of battery clusters 10, wherein the plurality of battery clusters 10 are connected in parallel to form a first node A and a first node B. The battery cluster 10 includes at least one battery pack 110 and a balancing circuit 120. The balancing circuit 120 includes a first switch unit 121 and a first adjustable resistor 122. One end of the first adjustable resistor 122 is electrically connected to a first end of the first switch unit 121 and one end of the battery pack 110, respectively. The other end of the first adjustable resistor 122 is electrically connected to a second end of the first switch unit 121. The third end of the first switch unit 121 is electrically connected to the first node B; or one end of the first adjustable resistor 122 The second end of the first switch unit 121 is electrically connected, and the other end of the first adjustable resistor 122 is electrically connected to the first end of the first switch unit 121 and the first node B respectively. The third end of the first switch unit 121 is electrically connected to one end of the battery pack 110. Therefore, when the battery cluster 10 needs to be balanced, it is only necessary to connect the second end and the third end of the first switch unit 121, and then the first adjustable resistor 122 can be used to balance the battery cluster 10, which can make the consistency between the battery clusters 10 in the energy storage system higher, and at the same time improve the balancing efficiency of the battery cluster 10, and reduce the power loss during the balancing process.

[0037] In some embodiments, when the battery cluster 10 does not need to be balanced, the first switch unit 121 is configured to be conductive between the first terminal and the third terminal, and disconnected between the second terminal and the third terminal.

[0038] In this embodiment, when a battery cluster 10 does not require balancing, the second and third terminals of the first switch unit 121 are disconnected, thereby preventing the battery cluster 10 that does not require balancing from being balanced. At the same time, to ensure normal charging and discharging of the battery cluster 10, the first and third terminals of the first switch unit 121 can be connected. The condition for determining whether a battery cluster 10 does not require balancing can be determined by determining whether the voltage difference between the battery cluster 10 and other battery clusters 10 is within a preset voltage range. If so, it is determined that the battery cluster 10 does not require balancing.

[0039] In some embodiments, as Figure 3 As shown, the first switch unit 121 includes a first balancing switch and a second balancing switch; wherein one end of the first balancing switch is electrically connected to one end of the first adjustable resistor 122 and one end of the battery pack 110, respectively; the other end of the first balancing switch is electrically connected to one end of the second balancing switch and the first node B, respectively; and the other end of the second balancing switch is electrically connected to the other end of the first adjustable resistor 122; when the battery cluster 10 needs to be balanced, the first balancing switch is configured to be disconnected at both ends, and the second balancing switch is configured to be connected at both ends.

[0040] In this embodiment, the first adjustable resistor 122 may be a resistor R1. The first adjustable resistor 122 is connected in series with the second balancing switch and then in parallel with the first balancing switch, and is disposed between one end of the battery pack 110 and the first node B. One end of the first balancing switch may serve as the third end of the first switch unit 121. After the other end of the first balancing switch is connected to one end of the second balancing switch, the connection point formed therebetween may serve as the first end of the first switch unit 121. The other end of the second balancing switch may serve as the second end of the first switch unit 121.

[0041] When the battery cluster 10 needs to be balanced, the first balancing switch is in the off state, and the resistance value of the first adjustable resistor 122 is adjusted. After the resistance value of the first adjustable resistor 122 is adjusted, the second balancing switch is closed, and the battery cluster 10 can be balanced.

[0042] In some embodiments, as Figure 4 As shown, the first switch unit 121 includes a single-pole double-throw switch SPDT; wherein, the first end of the single-pole double-throw switch SPDT is electrically connected to the other end of the first adjustable resistor 122 and the first node B, respectively, the second end of the single-pole double-throw switch SPDT is electrically connected to one end of the first adjustable resistor 122, and the third end of the single-pole double-throw switch SPDT is electrically connected to one end of the battery pack 110.

[0043] In this embodiment, the first switch unit 121 may include a single-pole double-throw switch (SPDT). The first, second, and third ends of the SPDT may serve as the first, second, and third ends of the first switch unit 121, respectively. The SPDT may be disposed between the first node B and the first adjustable resistor 122. When balancing the battery cluster 10 is required, the second and third ends of the SPDT are electrically connected. When balancing is not required, the first and third ends of the SPDT are electrically connected.

[0044] In some embodiments, the first switch unit 121 includes a single-pole double-throw switch SPDT; wherein, the first end of the single-pole double-throw switch SPDT is electrically connected to one end of the battery pack 110 and one end of the first adjustable resistor 122, respectively, the second end of the single-pole double-throw switch SPDT is electrically connected to the other end of the first adjustable resistor 122, and the third end of the single-pole double-throw switch SPDT is electrically connected to the first node B.

[0045] In this embodiment, a single-pole double-throw switch SPDT is provided between one end of the battery pack 110 and the first adjustable resistor 122. Furthermore, when the battery cluster 10 needs to be balanced, the second end and the third end of the single-pole double-throw switch SPDT are electrically connected; when the battery cluster 10 does not need to be balanced, the first end and the third end of the single-pole double-throw switch SPDT are electrically connected.

[0046] In some embodiments, as Figure 5 As shown, the balancing circuit 120 further includes a second adjustable resistor; wherein the first switch unit 121 further includes a fourth end, one end of the second adjustable resistor is electrically connected to the first end of the first switch unit 121 and one end of the battery pack 110, respectively, and the other end of the second adjustable resistor is electrically connected to the fourth end of the first switch unit 121; or, one end of the second adjustable resistor is electrically connected to the fourth end of the first switch unit 121, and the other end of the second adjustable resistor is electrically connected to the first end of the first switch unit 121 and the first node B, respectively; wherein, when the battery cluster 10 needs to be balanced, the first switch unit 121 is configured to conduct between the third end and the fourth end.

[0047] Specifically, the second adjustable resistor provided in the present application can serve as a backup resistor for the first adjustable resistor 122 , and can be connected in parallel with the first adjustable resistor 122 , so that when the first adjustable resistor 122 cannot balance the battery cluster 10 , the second adjustable resistor can be used to balance the battery cluster 10 .

[0048] Continue reading Figure 5The first switch unit 121 includes a switch K1, a switch K11, and a switch K12. The first adjustable resistor 122 may be a resistor R1, and the second adjustable resistor may be a resistor R3. The resistor R1 is connected in series with the switch K11 and then connected in parallel with the switch K1. At the same time, the resistor R3 is connected in series with the switch K12 and then connected in parallel with the switch K12.

[0049] In some embodiments, as Figure 6 As shown, the energy storage system also includes an energy storage converter 20, which includes: a first pre-charging circuit 210, a first end of the first pre-charging circuit 210 electrically connected to the first node A, a second end of the pre-charging circuit electrically connected to the first node B, and the first pre-charging circuit 210 is configured to perform power-on protection on the DC side of the energy storage converter 20; an inverter circuit 220, a first end of the inverter circuit 220 electrically connected to the third end of the first pre-charging circuit 210, and a second end of the inverter circuit 220 electrically connected to the first pre-charging circuit 210. The fourth end of the circuit 210, the inverter circuit 220 is configured to convert between AC and DC; the rectifier circuit 230, the first end of the rectifier circuit 230 is electrically connected to the third end of the inverter circuit 220, the second end of the rectifier circuit 230 is electrically connected to the fourth end of the inverter circuit 220, the third end of the rectifier circuit 230 is electrically connected to the fifth end of the inverter circuit 220, the fourth end, the fifth end and the sixth end of the rectifier circuit 230 are configured to be connected to the power grid, and the rectifier circuit 230 is configured to perform rectification and filtering.

[0050] Specifically, the power conversion system (PCS) 20 may include a first pre-charging circuit 210 , an inverter circuit 220 , and a rectifier circuit 230 . When the battery cluster 10 is discharging, the power conversion system 20 may convert direct current (DC) into alternating current (AC). The power conversion system 20 may also convert AC into DC to charge the battery.

[0051] In this embodiment, the energy storage converter 20 is an integrated energy storage converter 20, which provides a larger space for the energy storage system, thereby facilitating better wiring of the energy storage system. A first pre-charging circuit 210 can be provided on the DC side of the energy storage converter 20, so that the energy storage converter 20 can be pre-charged before the energy storage converter 20 is powered on to ensure the power safety of the DC side of the energy storage converter 20. At the same time, a rectifier circuit 230 is provided on the AC side of the energy storage converter 20, which can realize rectification and filtering on the AC side of the energy storage converter 20. Among them, the DC side voltage range of the energy storage converter 20 is relatively wide, which can be 1000V~1500V.

[0052] Furthermore, in some embodiments, Figure 8As shown, the first pre-charge circuit 210 includes a first pre-charge switch QF1, a second pre-charge switch M1, a third pre-charge switch QF2 and a fourth pre-charge switch KA1; wherein, one end of the first pre-charge switch QF1 is electrically connected to the first node A, the other end of the first pre-charge switch QF1 is electrically connected to one end of the second pre-charge switch M1, the other end of the second pre-charge switch M1 is electrically connected to the first end of the inverter circuit 220, one end of the third pre-charge switch QF2 is electrically connected to the first node B, the other end of the third pre-charge switch QF2 is electrically connected to one end of the fourth pre-charge switch KA1, and the other end of the fourth pre-charge switch KA1 is electrically connected to the second end of the inverter circuit 220.

[0053] In this embodiment, the first pre-fill switch QF1 can be a circuit breaker, the second pre-fill switch M1 can be a DC connection switch, the third pre-fill switch QF2 can be a circuit breaker, and the fourth pre-fill switch KA1 can be a relay. The second pre-fill switch M1 is the main switch on the DC side of the energy storage converter 20. When the energy storage converter 20 needs to be powered on, the second pre-fill switch M1 needs to be closed first, and then the first pre-fill switch QF1, the third pre-fill switch QF2, and the fourth pre-fill switch KA1 need to be closed respectively. The first pre-fill switch QF1, the third pre-fill switch QF2, and the fourth pre-fill switch KA1 can also be disconnected in time when a short circuit occurs on the DC side of the energy storage converter 20, so as to provide short-circuit protection on the DC side of the energy storage converter 20.

[0054] At the same time, the present application may also provide a fuse FU4 between the first pre-charge switch QF1 and the second pre-charge switch M1, and a fuse FU5 between the third pre-charge switch QF2 and the fourth pre-charge switch KA1, so as to better and more comprehensively provide short-circuit protection for the energy storage system when short-circuit currents of different sizes appear on the DC side of the energy storage converter 20.

[0055] Continue reading Figure 8 The first pre-charging circuit 210 also includes a fifth pre-charging switch KA2 and a pre-charging resistor R2; wherein, one end of the fifth pre-charging switch KA2 is electrically connected to the other end of the third pre-charging switch QF2 and one end of the fourth pre-charging switch KA1, respectively, the other end of the fifth pre-charging switch KA2 is electrically connected to one end of the pre-charging resistor R2, and one end of the pre-charging resistor R2 is electrically connected to the other end of the fourth pre-charging switch KA1.

[0056] In this embodiment, the fifth pre-charging switch KA2 is connected in series with the pre-charging resistor R2 and then connected in parallel with the fourth pre-charging switch KA1. The fifth pre-charging switch KA2 and the pre-charging resistor R2 can be arranged at the positive end of the DC side of the energy storage converter 20. This can avoid the situation where the fifth pre-charging switch KA2 is closed first and the fourth pre-charging switch KA1 is disconnected due to the large instantaneous current when the energy storage converter 20 is powered on. The pre-charging resistor R2 can reduce the instantaneous current by generating heat, so that after the current at the positive end of the DC side stabilizes, the fourth pre-charging switch KA1 is closed and the fifth pre-charging switch KA2 is disconnected.

[0057] In some embodiments, as Figure 7 As shown, the energy storage converter 20 further includes a second pre-charging circuit 240; wherein, the first end of the second pre-charging circuit 240 is electrically connected to the third end of the rectifier circuit 230, the second end of the second pre-charging circuit 240 is electrically connected to the fourth end of the rectifier circuit 230, the third end of the second pre-charging circuit 240 is electrically connected to the fifth end of the rectifier circuit 230, the fourth end, the fifth end and the sixth end of the second pre-charging circuit 240 are configured to be connected to the power grid, and the second pre-charging circuit 240 is configured to perform power-on protection on the AC side of the energy storage converter 20.

[0058] Specifically, the present application may further provide a second pre-charging circuit 240 on the AC side of the energy storage converter 20. Furthermore, before the energy storage converter 20 is powered on, the first pre-charging circuit 210 and the second pre-charging circuit 240 may be used to pre-charge the energy storage converter 20 to ensure power safety on both the DC and AC sides of the energy storage converter 20. The power supply on the AC side of the energy storage converter 20 may be a three-phase AC power supply.

[0059] It should be noted that, in the present application, a pre-charging circuit may be provided only on the DC side of the energy storage converter 20 , or only on the AC side of the energy storage converter 20 , or a pre-charging circuit may be provided on both the DC side and the AC side of the energy storage converter 20 .

[0060] Continue reading Figure 8 The AC side of the energy storage converter 20 is three-phase AC power, and each phase is equipped with relays, fuses and circuit breakers. Therefore, the second pre-charging circuit 240 can include a relay KA3, a circuit breaker QF3, a fuse FU6 and a circuit breaker QF4 connected in series, a relay KA4, a circuit breaker QF5, a fuse FU7 and a circuit breaker QF6 connected in series, and a relay KA5, a circuit breaker QF7, a fuse FU8 and a circuit breaker QF8 connected in series.

[0061] Furthermore, if Figure 8As shown, inverter circuit 220 can be a DC / AC circuit, including a first terminal, a second terminal, a third terminal, a fourth terminal, and a fifth terminal. The first and second terminals of inverter circuit 220 are arranged on the DC side, and a capacitor C4 is arranged between the first and second terminals. The third, fourth, and fifth terminals are arranged on the AC side. Rectifier circuit 230 can be an LCL rectifier circuit 230, which can include capacitors C1, C2, C3, and inductors L1, L2, and L3.

[0062] In some embodiments, as Figure 3 、 Figure 4 and Figure 5 As shown, the battery cluster also includes a third pre-charging circuit; wherein, the first end of the third pre-charging circuit is electrically connected to one end of the battery pack 110, the second end of the third pre-charging circuit is electrically connected to the other end of the battery pack 110, the third end of the third pre-charging circuit is electrically connected to the first node A, and the fourth end of the third pre-charging circuit is electrically connected to the balancing circuit 120. The third pre-charging circuit is configured to perform power-on protection on the battery pack 110.

[0063] In this embodiment, the third pre-charging circuit is provided between the battery pack 110 and the balancing circuit 120. Before the energy storage system is powered on, the third pre-charging circuit is first used for power-on protection, and then the balancing circuit 120 is used to balance the voltages of the corresponding battery clusters 10, thereby ensuring that the voltages of the battery clusters 10 in the energy storage system are more consistent.

[0064] For further information, please refer to Figure 3 、 Figure 4 and Figure 5 The third pre-charging circuit includes a sixth pre-charging switch KA6, a seventh pre-charging switch KA7 and an eighth pre-charging switch KA8; wherein, one end of the sixth pre-charging switch KA6 and one end of the seventh pre-charging switch KA7 are both electrically connected to one end of the battery pack 110, the other end of the sixth pre-charging switch KA6 and the other end of the seventh pre-charging switch KA7 are both electrically connected to the balancing circuit 120, one end of the eighth pre-charging switch KA8 is electrically connected to the other end of the battery pack 110, and the other end of the eighth pre-charging switch KA8 is electrically connected to the first node A.

[0065] In this embodiment, one end of the battery pack 110 can be a positive electrode, and the other end can be a negative electrode. The sixth pre-charge switch KA6 and the seventh pre-charge switch KA7 are located at the positive electrode of the battery pack 110, and the eighth pre-charge switch KA8 is located at the negative electrode of the battery pack 110. The sixth pre-charge switch KA6, the seventh pre-charge switch KA7, and the eighth pre-charge switch KA8 can all be contactors. When the battery cluster 10 needs to be powered on, the seventh pre-charge switch KA7 and the eighth pre-charge switch KA8 can be closed first to perform pre-charging. After pre-charging is complete, the seventh pre-charge switch KA7 is opened, and the sixth pre-charge switch KA6 is closed.

[0066] Furthermore, in order to more comprehensively protect the battery cluster 10 , the present application may also set a fuse FU1 in the battery pack 110 , and connect a fuse FU3 in series at the sixth pre-charge switch KA6 , and a fuse FU2 in series at the eighth pre-charge switch KA8 .

[0067] In addition, a maintenance switch MSD can be set in the battery pack 110, a Hall current sensor Hall is connected in series at the eighth pre-charge switch KA8, a Hall current sensor Hall is connected in series at the sixth pre-charge switch KA6, and a shunt current sensor Shunt is set between the fuse FU3 and the positive pole of the battery pack 110.

[0068] In some embodiments, as Figure 1 、 Figure 2 、 Figure 6 as well as Figure 7 As shown, the energy storage system further includes an isolating switch 30; a first end of the isolating switch 30 is electrically connected to the first node A, a second end of the isolating switch 30 is electrically connected to the first node B, and a third end and a fourth end of the isolating switch 30 are respectively configured to be electrically connected to a target device. The isolating switch 30 is configured to open or close the circuit of the battery cluster 10. Specifically, the isolating switch 30 can be provided between the DC side of the energy storage converter 20 and the battery cluster 10, thereby isolating the energy storage converter 20 from the battery cluster 10.

[0069] In some embodiments, as Figure 3 、 Figure 4 and Figure 5 As shown, the energy storage system further includes a battery array management unit 40 , which is configured to control the on / off between the second terminal and the third terminal of the first switch unit 121 and adjust the resistance value of the first adjustable resistor 122 .

[0070] In this embodiment, the battery array management system (BAMS) 40 controls the connection between the second and third terminals of the first switch unit 121 and also adjusts the resistance of the first adjustable resistor 122. When the battery cluster 10 needs to be balanced, the BAMS 40 adjusts the resistance of the first adjustable resistor 122 to a preset value and connects the second and third terminals of the first switch unit 121. When the battery cluster 10 is balanced, the BAMS 40 connects the first and third terminals of the first switch unit 121 and disconnects the second and third terminals of the first switch unit 121.

[0071] Continue reading Figure 3 、 Figure 4 and Figure 5As shown, the battery array management unit 40 also includes at least one battery cluster management unit 410, and the battery cluster management unit 410 includes at least one battery pack 110 management unit; wherein, the battery pack 110 management unit is configured to collect the voltage signal of the single cell in the battery pack 110, and the battery cluster management unit 410 is configured to process the voltage signal, and the battery array management unit 40 is configured to control the connection and disconnection between the second end and the third end of the first switch unit 121 and adjust the resistance value of the first adjustable resistor 122 according to the processing information of the voltage signal uploaded by the battery cluster management unit 410.

[0072] In this embodiment, the battery array management unit 40 also includes at least one battery cluster management unit (BCMU) 410. Each BCMU 410 can control the connection between the second and third terminals of the first switch unit 121 and adjust the resistance of the first adjustable resistor 122. When the battery cluster 10 needs to be balanced, the BCMU 410 adjusts the resistance of the first adjustable resistor 122 to a preset value and connects the second and third terminals of the first switch unit 121. When the battery cluster 10 is balanced, the BCMU 410 connects the first and third terminals of the first switch unit 121 and disconnects the second and third terminals of the first switch unit 121.

[0073] Furthermore, the battery cluster management unit 410 includes at least one battery module management unit 4101 (BMU). Each battery pack 110 corresponds to a battery module management unit 4101. Battery module management can be used to collect current and voltage of each battery cell in the battery pack 110. The battery module management unit 4101 can send the collected information to the battery cluster management unit 410. The battery cluster management unit 410 can summarize and process the information sent by the battery module management unit 4101, and then enable the battery array management unit 40 to balance the corresponding battery cluster 10 according to the summarized and processed information of the battery cluster management unit 410.

[0074] In addition, voltage and / or current can be collected at the negative terminal of the DC side of the energy storage converter 20 through the battery cell management unit 4101 .

[0075] In some embodiments, as Figure 9 As shown, the present application further provides a balancing method, which is applied to the energy storage system in the above embodiment. The balancing method includes steps S110, S120 and S130.

[0076] S110, obtaining a first voltage difference between two battery clusters 10; wherein the two battery clusters 10 are a first battery cluster 10 and a second battery cluster 10, and the first battery cluster 10 and the second battery cluster 10 are connected in parallel; S120 , if the first voltage difference is greater than a preset first voltage and less than a preset second voltage, adjusting the resistance value of the first adjustable resistor 122 in the first battery cluster 10 ; S130 , controlling the second terminal and the third terminal of the first switch unit 121 in the first battery cluster 10 to be conductive; wherein the cluster terminal voltage of the first battery cluster 10 is greater than the cluster terminal voltage of the second battery cluster 10 .

[0077] In this embodiment, the first voltage and the second voltage are critical voltages at which one of the two battery clusters 10 needs to be balanced. When the voltage difference between the two battery clusters 10, i.e., the first voltage difference, is greater than the first voltage but less than the second voltage, the battery cluster 10 with the larger cluster terminal voltage among the two battery clusters 10 needs to be balanced. The balancing circuit 120 in the battery cluster 10 can then balance the battery clusters 10. The first voltage can be 5V, and the second voltage can be 20V.

[0078] Furthermore, when there are more than three battery clusters 10 in the energy storage system, the battery cluster 10 with the smallest cluster terminal voltage can be determined in advance, and then the first voltage difference between the battery cluster 10 and the other battery clusters 10 can be obtained. Then, it is determined whether each first voltage difference is between the first voltage and the second voltage. If so, the battery clusters 10 in the energy storage system other than the battery cluster 10 with the smallest cluster terminal voltage are balanced.

[0079] In some embodiments, as Figure 10 As shown, before step S110, steps S210, S220 and S230 are also included.

[0080] S210 , obtaining a second voltage difference between the two battery clusters 10 ; S220: If the second voltage difference is less than or equal to a preset third voltage, control the seventh pre-charge switch KA7 and the eighth pre-charge switch KA8 in the first battery cluster 10 to be closed; S230: If the second voltage difference is greater than the third voltage, control the sixth pre-charge switch KA6 and the eighth pre-charge switch KA8 in the first battery cluster 10 to be closed, and after the closing reaches a preset first time, control the sixth pre-charge switch KA6 to be opened and the seventh pre-charge switch KA7 to be closed.

[0081] In this embodiment, the second voltage difference is the cluster-terminal voltage difference before powering up the battery cluster 10 in the energy storage system. Before powering up, the battery cluster 10 must first be precharged using the third precharging circuit. After the precharging is complete, i.e., after the precharging reaches the first time, the battery clusters 10 in the energy storage system can be balanced, thereby better ensuring voltage consistency among the battery clusters 10. The third voltage is the critical voltage that determines whether the battery cluster 10 needs to be precharged, and the third voltage is greater than or equal to the second voltage.

[0082] In some embodiments, as Figure 11 As shown, the balancing method provided in this application further includes steps S310, S320 and S330.

[0083] S310, obtaining a third voltage difference between the first battery cluster 10 and the second battery cluster 10 after the conduction between the second terminal and the third terminal of the first switch unit 121 in the first battery cluster 10 reaches a preset second time; S320: If the third voltage difference is less than or equal to a preset fourth voltage, control the first switch unit 121 in the first battery cluster 10 to be conductive between the first terminal and the third terminal, and to be disconnected between the second terminal and the third terminal; S330 : If the third voltage difference is greater than the fourth voltage, generate fault information of the first battery cluster 10 .

[0084] Specifically, after the battery clusters 10 in the energy storage system are balanced for a preset second time, the voltage difference between the battery clusters 10, i.e., the third voltage difference, can be obtained again. It is then determined whether the third voltage difference is greater than a preset fourth voltage. If it is greater than the fourth voltage, it can be determined that a balancing failure has occurred in the battery cluster 10, and fault information for the battery cluster 10 can be generated. If it is not greater than the fourth voltage, it can be determined that the battery cluster 10 has been successfully balanced, and the first terminal and the third terminal of the first switch unit 121 in the battery cluster 10 can be controlled to be conductive, and the second terminal and the third terminal of the first switch unit 121 can be controlled to be disconnected, so as to power on the battery cluster 10. The fourth voltage is less than or equal to the first voltage.

[0085] 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 person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present application, and such modifications or substitutions 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: The invention comprises a plurality of battery clusters, wherein the plurality of battery clusters are connected in parallel to form a first node and a second node, and at least one of the battery clusters comprises: at least one battery pack; A balancing circuit, comprising a first switch unit and a first adjustable resistor, wherein the first switch unit comprises a first end, a second end and a third end, wherein one end of the first adjustable resistor is electrically connected to the first end of the first switch unit and one end of the battery pack, respectively, the other end of the first adjustable resistor is electrically connected to the second end of the first switch unit, and the third end of the first switch unit is electrically connected to the second node; or, one end of the first adjustable resistor is electrically connected to the second end of the first switch unit, the other end of the first adjustable resistor is electrically connected to the first end of the first switch unit and the second node, respectively, and the third end of the first switch unit is electrically connected to one end of the battery pack; Wherein, when the battery cluster needs to be balanced, the first switch unit is configured to be conductive between the second end and the third end.

2. The energy storage system according to claim 1, characterized in that: When the battery cluster does not need to be balanced, the first switch unit is configured to be conductive between the first terminal and the third terminal, and disconnected between the second terminal and the third terminal.

3. The energy storage system according to claim 1, characterized in that: The first switch unit includes a first balancing switch and a second balancing switch; One end of the first balancing switch is electrically connected to one end of the first adjustable resistor and one end of the battery pack, the other end of the first balancing switch is electrically connected to one end of the second balancing switch and the second node, and the other end of the second balancing switch is electrically connected to the other end of the first adjustable resistor; When the battery cluster needs to be balanced, the first balancing switch is configured to be disconnected at both ends, and the second balancing switch is configured to be connected at both ends.

4. The energy storage system according to claim 1, characterized in that: The first switch unit includes a single-pole double-throw switch; Among them, the first end of the single-pole double-throw switch is electrically connected to one end of the battery pack and one end of the first adjustable resistor, the second end of the single-pole double-throw switch is electrically connected to the other end of the first adjustable resistor, and the third end of the single-pole double-throw switch is electrically connected to the second node; or, the first end of the single-pole double-throw switch is electrically connected to the other end of the first adjustable resistor and the second node, the second end of the single-pole double-throw switch is electrically connected to one end of the first adjustable resistor, and the third end of the single-pole double-throw switch is electrically connected to one end of the battery pack.

5. The energy storage system according to claim 1, characterized in that: The equalization circuit also includes a second adjustable resistor; Wherein, the first switch unit further includes a fourth end, one end of the second adjustable resistor is electrically connected to the first end of the first switch unit and one end of the battery pack, and the other end of the second adjustable resistor is electrically connected to the fourth end of the first switch unit; or, one end of the second adjustable resistor is electrically connected to the fourth end of the first switch unit, and the other end of the second adjustable resistor is electrically connected to the first end of the first switch unit and the second node; Wherein, when the battery cluster needs to be balanced, the first switch unit is configured to be conductive between the third terminal and the fourth terminal.

6. The energy storage system according to claim 1, characterized in that: The energy storage system further includes an energy storage converter, which includes: A first pre-charging circuit, wherein a first end of the first pre-charging circuit is electrically connected to the first node, a second end of the pre-charging circuit is electrically connected to the second node, and the first pre-charging circuit is configured to perform power-on protection on a DC side of the energy storage converter; an inverter circuit, wherein a first end of the inverter circuit is electrically connected to a third end of the first pre-charging circuit, a second end of the inverter circuit is electrically connected to a fourth end of the first pre-charging circuit, and the inverter circuit is configured to convert between alternating current and direct current; A rectifier circuit, wherein a first end of the rectifier circuit is electrically connected to a third end of the inverter circuit, a second end of the rectifier circuit is electrically connected to a fourth end of the inverter circuit, a third end of the rectifier circuit is electrically connected to a fifth end of the inverter circuit, the fourth end, the fifth end and the sixth end of the rectifier circuit are configured to be connected to a power grid, and the rectifier circuit is configured to perform rectification and filtering.

7. The energy storage system according to claim 6, characterized in that: The first pre-charging circuit includes a first pre-charging switch, a second pre-charging switch, a third pre-charging switch and a fourth pre-charging switch; Among them, one end of the first pre-fill switch is electrically connected to the first node, the other end of the first pre-fill switch is electrically connected to one end of the second pre-fill switch, the other end of the second pre-fill switch is electrically connected to the first end of the inverter circuit, one end of the third pre-fill switch is electrically connected to the second node, the other end of the third pre-fill switch is electrically connected to one end of the fourth pre-fill switch, and the other end of the fourth pre-fill switch is electrically connected to the second end of the inverter circuit.

8. The energy storage system according to claim 7, characterized in that: The first pre-charging circuit further includes a fifth pre-charging switch and a pre-charging resistor; Among them, one end of the fifth pre-charge switch is electrically connected to the other end of the third pre-charge switch and one end of the fourth pre-charge switch, the other end of the fifth pre-charge switch is electrically connected to one end of the pre-charge resistor, and one end of the pre-charge resistor is electrically connected to the other end of the fourth pre-charge switch.

9. The energy storage system according to claim 6, characterized in that: The energy storage converter also includes a second pre-charging circuit; Among them, the first end of the second pre-charging circuit is electrically connected to the third end of the rectifier circuit, the second end of the second pre-charging circuit is electrically connected to the fourth end of the rectifier circuit, the third end of the second pre-charging circuit is electrically connected to the fifth end of the rectifier circuit, the fourth end, the fifth end and the sixth end of the second pre-charging circuit are configured to be connected to the power grid, and the second pre-charging circuit is configured to power on protection of the AC side of the energy storage inverter.

10. The energy storage system according to any one of claims 1 to 9, characterized in that: The battery cluster further includes a third pre-charging circuit; Among them, the first end of the third pre-charging circuit is electrically connected to one end of the battery pack, the second end of the third pre-charging circuit is electrically connected to the other end of the battery pack, the third end of the third pre-charging circuit is electrically connected to the first node, and the fourth end of the third pre-charging circuit is electrically connected to the balancing circuit. The third pre-charging circuit is configured to perform power-on protection on the battery pack.

11. The energy storage system according to claim 10, characterized in that: The third pre-charging circuit includes a sixth pre-charging switch, a seventh pre-charging switch and an eighth pre-charging switch; Among them, one end of the sixth pre-charge switch and one end of the seventh pre-charge switch are both electrically connected to one end of the battery pack, the other end of the sixth pre-charge switch and the other end of the seventh pre-charge switch are both electrically connected to the balancing circuit, one end of the eighth pre-charge switch is electrically connected to the other end of the battery pack, and the other end of the eighth pre-charge switch is electrically connected to the first node.

12. The energy storage system according to any one of claims 1 to 9, characterized in that: The energy storage system also includes an isolating switch; The first end of the isolation switch is electrically connected to the first node, the second end of the isolation switch is electrically connected to the second node, the third end and the fourth end of the isolation switch are respectively configured to be electrically connected to the target device, and the isolation switch is configured to turn on or off the circuit of the battery cluster.

13. The energy storage system according to any one of claims 1 to 9, characterized in that: The energy storage system further includes a battery array management unit, which is configured to control the on-off between the second end and the third end of the first switch unit and adjust the resistance value of the first adjustable resistor.

14. The energy storage system according to claim 13, characterized in that: The battery array management unit further comprises at least one battery cluster management unit, and the battery cluster management unit comprises at least one battery pack management unit; Among them, the battery pack management unit is configured to collect voltage signals of single cells in the battery pack, the battery cluster management unit is configured to process the voltage signals, and the battery array management unit is configured to control the on and off between the second end and the third end of the first switch unit and adjust the resistance value of the first adjustable resistor according to the processing information of the voltage signal uploaded by the battery cluster management unit.

15. A balancing method, characterized in that: Applied to the energy storage system according to any one of claims 1 to 14, the balancing method comprises: Obtaining a first voltage difference between the two battery clusters; wherein the two battery clusters are a first battery cluster and a second battery cluster, and the first battery cluster and the second battery cluster are connected in parallel; If the first voltage difference is greater than a preset first voltage and less than a preset second voltage, adjusting the resistance value of the first adjustable resistor in the first battery cluster; The second terminal and the third terminal of the first switch unit in the first battery cluster are controlled to be conductive; wherein the cluster terminal voltage of the first battery cluster is greater than the cluster terminal voltage of the second battery cluster.

16. The equalization method according to claim 15, characterized in that: Before obtaining the first voltage difference between the two battery clusters, the method further includes: acquiring a second voltage difference between the two battery clusters; If the second voltage difference is less than or equal to a preset third voltage, controlling the seventh pre-charge switch and the eighth pre-charge switch in the first battery cluster to be closed; If the second voltage difference is greater than the third voltage, the sixth pre-charging switch and the eighth pre-charging switch in the first battery cluster are controlled to be closed, and after being closed for a preset first time, the sixth pre-charging switch is controlled to be opened and the seventh pre-charging switch is controlled to be closed.

17. The equalization method according to claim 15, characterized in that: The balancing method further comprises: After the second terminal and the third terminal of the first switch unit in the first battery cluster are turned on for a preset second time, obtaining a third voltage difference between the first battery cluster and the second battery cluster; If the third voltage difference is less than or equal to a preset fourth voltage, controlling the first terminal and the third terminal of the first switch unit in the first battery cluster to be conductive, and the second terminal and the third terminal to be disconnected; If the third voltage difference is greater than the fourth voltage, fault information of the first battery cluster is generated.

Images