Inter-cluster balance control method and device

Abstract

The embodiment of the invention provides an inter-cluster equalization control method and device, the inter-cluster equalization control method is applied to an energy storage system, the energy storage system comprises a first equalization bus, a second equalization bus and a plurality of battery clusters, and each battery cluster is connected in parallel to the first equalization bus and is connected in parallel to the second equalization bus. The second equalization bus is connected with an external power supply through a power supply conversion module. The method comprises the following steps: identifying a voltage value and a capacity value of each battery cluster; when it is determined that voltage balancing and capacity balancing need to be carried out on the multiple battery clusters according to the voltage value or the capacity value, balancing loops formed by the first battery cluster and the second battery cluster in the multiple battery clusters and the first balancing bus are controlled to be closed, and balancing loops formed by the remaining battery clusters and the second balancing bus are controlled to be closed; and charging and discharging the first battery cluster and the second battery cluster through the first equalization bus, and transmitting energy between the external power supply and the remaining battery clusters through the second equalization bus, so as to perform voltage and capacity equalization on the plurality of battery clusters.

Description

Technical Field

[0001] The embodiments in this specification relate to the field of battery energy storage technology, and in particular to inter-cluster equalization control methods. Background Technology

[0002] In energy storage systems, individual batteries are connected in series and parallel to form battery boxes, and battery boxes are connected in series and parallel to form battery clusters. Multiple battery clusters are directly connected in parallel to the same DC bus. Inter-cluster balancing in energy storage systems is a key technology to ensure the safe and efficient operation of the system.

[0003] However, current energy storage systems mostly employ a cluster balancing approach by sequentially merging each battery cluster. This method suffers from long balancing times and limited applicability, ultimately impacting system performance and lifespan. Therefore, an effective method is urgently needed to address these issues. Summary of the Invention

[0004] In view of this, embodiments of this specification provide an inter-cluster load balancing control method. One or more embodiments of this specification also relate to an inter-cluster load balancing control device, a computing device, a computer-readable storage medium, and a computer program, to address the technical deficiencies existing in the prior art.

[0005] According to a first aspect of the embodiments of this specification, an inter-cluster equalization control method is provided, applied to an energy storage system. The energy storage system includes a first equalization bus, a second equalization bus, and multiple battery clusters. The multiple battery clusters are connected in parallel to the first equalization bus and in parallel to the second equalization bus. The second equalization bus is connected to an external power source through a power conversion module. The method includes: Identify the voltage and capacity values ​​of each battery cluster; When it is determined that voltage balancing and capacity balancing of multiple battery clusters are required based on the voltage value or the capacity value, the balancing loops formed by the first battery cluster and the second battery cluster in the multiple battery clusters and the first balancing bus are controlled to close, and the balancing loops formed by the remaining battery clusters in the multiple battery clusters and the second balancing bus are controlled to close. The first battery cluster and the second battery cluster are charged and discharged through the first equalization bus, and energy is transferred between the external power source and the remaining battery clusters through the second equalization bus to balance the voltage and capacity of the multiple battery clusters.

[0006] Optionally, the first balancing bus includes a positive output bus and a negative output bus, with each battery cluster connected to the positive output bus and the negative output bus at both ends, respectively. The positive output bus and the negative output bus are connected to an energy storage converter. The method further includes: When the energy storage system is in normal operation, one end of the first target battery cluster is connected to the output positive bus via a main positive relay and a first switch, and the other end is connected to the output negative bus via a main negative relay and a second switch, and is charged or discharged through the energy storage converter; When the energy storage system is in an inter-cluster equilibrium state, one end of the first target battery cluster is connected to the positive output bus via a circulating current relay, a circulating current resistor, and the first switch, and the other end is connected to the negative output bus via the main negative relay and the second switch. The first target battery cluster is each of the plurality of battery clusters.

[0007] Optionally, the first battery cluster, the first circulating current relay, the first circulating current resistor, the first switch, the first main negative relay, and the second switch form a first balancing circuit with the first balancing bus, and the second battery cluster, the second circulating current relay, the second circulating current resistor, the third switch, the second main negative relay, and the fourth switch form a second balancing circuit with the first balancing bus.

[0008] Optionally, the inter-cluster balance control method further includes: The voltage imbalance and remaining capacity imbalance of each battery cluster are determined based on the voltage value and the capacity value. The battery clusters that require voltage and capacity balancing are determined based on the voltage imbalance or the remaining capacity imbalance.

[0009] Optionally, the energy transfer between the external power source and the remaining battery cluster via the second balancing bus includes: The power conversion module converts the electricity supplied by the external power source and transmits the converted electricity to the remaining battery clusters via the second balancing bus to charge the remaining battery clusters; or... The power conversion module converts the output power of the remaining battery cluster and transmits the converted power to the external power source through the second equalization bus to discharge the remaining battery cluster. Wherein, when the external power source provides AC power, the power conversion module is an AC-DC module; when the external power source provides DC power, the power conversion module is a DC-DC module.

[0010] According to a second aspect of the embodiments of this specification, another inter-cluster equalization control method is provided, applied to an energy storage system. The energy storage system includes a first equalization bus, a second equalization bus, and multiple battery clusters. The multiple battery clusters are connected in parallel to the first equalization bus and in parallel to the second equalization bus. The second equalization bus is connected to an external power source through a power conversion module. The method includes: Identify the capacity value of each battery cluster; When it is determined that capacity balancing of the second target battery cluster is required based on the capacity value, the balancing loop formed by the second target battery cluster and the second balancing bus is controlled to close, wherein the second target battery cluster is one or at least two of the plurality of battery clusters; The second target battery cluster is charged and discharged through the second equalization bus to equalize its capacity.

[0011] Optionally, the energy storage system further includes a third balancing bus, the two ends of which are respectively connected to the first balancing bus and the second balancing bus, and are connected in series with the DC-DC module; Accordingly, the method further includes: When it is determined that at least two battery clusters need to be balanced based on the capacity value, the balancing loop formed by the third battery cluster in the at least two battery clusters and the second balancing bus is closed, and the balancing loop formed by the remaining battery clusters in the at least two battery clusters and the third balancing bus is closed respectively. The third battery cluster is charged and discharged through the second equalization bus, and the remaining battery clusters in the at least two battery clusters are charged and discharged through the third equalization bus to achieve capacity equalization of the at least two battery clusters.

[0012] Optionally, the energy storage system may further include a control unit; Accordingly, the method further includes: The control unit controls the balancing current and balancing time of the second target battery cluster. If the conditions for battery cluster balancing to be completed are met, the balancing switch in the balancing circuit is disconnected by the control unit. The control unit controls the closing of the main positive relay and main negative relay of the second target battery cluster to enter the normal charging and discharging mode.

[0013] According to a third aspect of the embodiments of this specification, an inter-cluster equalization control device is provided, applied to an energy storage system. The energy storage system includes a first equalization bus, a second equalization bus, and multiple battery clusters. The multiple battery clusters are connected in parallel to the first equalization bus and in parallel to the second equalization bus. The second equalization bus is connected to an external power source through a power conversion module. The device includes: The first identification module is configured to identify the voltage and capacity values ​​of each battery cluster. The first control module is configured to, when it is determined that voltage balancing and capacity balancing of multiple battery clusters need to be performed based on the voltage value or the capacity value, control the balancing loops formed by the first battery cluster and the second battery cluster in the multiple battery clusters respectively with the first balancing bus to close, and control the balancing loops formed by the remaining battery clusters in the multiple battery clusters respectively with the second balancing bus to close. The first processing module is configured to charge and discharge the first battery cluster and the second battery cluster through the first balancing bus, and to transfer energy between the external power source and the remaining battery clusters through the second balancing bus, so as to balance the voltage and capacity of the multiple battery clusters.

[0014] According to a fourth aspect of the embodiments of this specification, another inter-cluster equalization control device is provided, applied to an energy storage system. The energy storage system includes a first equalization bus, a second equalization bus, and multiple battery clusters. The multiple battery clusters are connected in parallel to the first equalization bus and in parallel to the second equalization bus. The second equalization bus is connected to an external power source via a power conversion module. The device includes: The second identification module is configured to identify the capacity value of each battery cluster; The second control module is configured to control the balancing loop formed by the second target battery cluster and the second balancing bus to close when it is determined that the second target battery cluster needs to be balanced based on the capacity value, wherein the second target battery cluster is one or at least two of the plurality of battery clusters. The second processing module is configured to perform charge and discharge processing on the second target battery cluster through the second equalization bus to equalize the capacity of the second target battery cluster.

[0015] According to a fifth aspect of the embodiments of this specification, a computing device is provided, comprising: Memory and processor; The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement any of the steps of the inter-cluster balance control method.

[0016] According to a sixth aspect of the embodiments of this specification, a computer-readable storage medium is provided that stores computer-executable instructions, which, when executed by a processor, implement the steps of any of the inter-cluster load balancing control methods described herein.

[0017] According to a seventh aspect of the embodiments of this specification, a computer program is provided, wherein when the computer program is executed in a computer, it causes the computer to perform the steps of the above-described inter-cluster equalization control method.

[0018] The inter-cluster equalization control method provided in this specification is applied to an energy storage system. The energy storage system includes a first equalization bus, a second equalization bus, and multiple battery clusters. Each battery cluster is connected in parallel to the first equalization bus and also in parallel to the second equalization bus. The second equalization bus is connected to an external power source via a power conversion module. By identifying the voltage and capacity values ​​of each battery cluster, when it is determined that voltage and capacity equalization of multiple battery clusters is required based on the voltage or capacity values, the equalization loops formed by the first and second battery clusters and the first equalization bus are closed, and the equalization loops formed by the remaining battery clusters and the second equalization bus are also closed. The first and second battery clusters are charged and discharged through the first equalization bus, and energy is transferred between the external power source and the remaining battery clusters through the second equalization bus to achieve voltage and capacity equalization of multiple battery clusters. This specification embodiment can simultaneously achieve voltage and capacity equalization between any two clusters through multiple equalization buses and various equalization strategies. This not only helps reduce equalization time and increase applicable scenarios but also effectively improves the equalization capability of the energy storage system, thereby improving the safety of the energy storage system and extending its service life. Attached Figure Description

[0019] Figure 1 This is a flowchart of an inter-cluster balance control method provided in one embodiment of this specification; Figure 2 This is a schematic diagram of an energy storage system provided in one embodiment of this specification; Figure 3 This is a flowchart of another inter-cluster balance control method provided in one embodiment of this specification; Figure 4 This is a schematic diagram showing the flow direction of charging energy in an energy storage system according to one embodiment of this specification; Figure 5 This is a schematic diagram showing the flow direction of discharge energy in an energy storage system according to one embodiment of this specification; Figure 6 This is a schematic diagram of the structure of an inter-cluster equalization control device provided in one embodiment of this specification; Figure 7This is a schematic diagram of another inter-cluster equalization control device provided in one embodiment of this specification; Figure 8 This is a structural block diagram of a computing device provided in one embodiment of this specification. Detailed Implementation

[0020] Many specific details are set forth in the following description to provide a full understanding of this specification. However, this specification can be implemented in many other ways than those described herein, and those skilled in the art can make similar extensions without departing from the spirit of this specification. Therefore, this specification is not limited to the specific implementations disclosed below.

[0021] The terminology used in one or more embodiments of this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the one or more embodiments of this specification. The singular forms “a,” “described,” and “the” as used in one or more embodiments of this specification and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in one or more embodiments of this specification refers to and includes any or all possible combinations of one or more associated listed items.

[0022] It should be understood that although the terms first, second, etc., may be used to describe various information in one or more embodiments of this specification, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, first may also be referred to as second without departing from the scope of one or more embodiments of this specification, and similarly, second may also be referred to as first. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to a determination."

[0023] First, the terms and concepts used in one or more embodiments of this specification will be explained.

[0024] Busbar (BUS): A highly conductive metallic conductor used in an electric power system to collect and distribute electrical energy.

[0025] This specification provides an inter-cluster load balancing control method, and also relates to an inter-cluster load balancing control device, a computing device, a computer-readable storage medium, and a computer program, which will be described in detail in the following embodiments.

[0026] Figure 1A flowchart of an inter-cluster equalization control method according to an embodiment of this specification is shown. The method is applied to an energy storage system, which includes a first equalization bus, a second equalization bus, and multiple battery clusters. The multiple battery clusters are connected in parallel to the first equalization bus and in parallel to the second equalization bus. The second equalization bus is connected to an external power source through a power conversion module. The method specifically includes the following steps.

[0027] Step 102: Identify the voltage and capacity values ​​of each battery cluster.

[0028] A schematic diagram of an energy storage system provided in the embodiments of this specification is shown below. Figure 2 As shown. From Figure 2 As can be seen from the diagram, the energy storage system includes a first balancing bus, a second balancing bus, and multiple battery clusters. The multiple battery clusters are connected in parallel to the first balancing bus and in parallel to the second balancing bus. The second balancing bus is connected to an external power source through a power conversion module.

[0029] In practical applications, the power conversion module can be an AC-DC module or a DC-DC module.

[0030] Among them, for the first equalization bus, the output sides of multiple battery clusters are connected in parallel to the bus. By controlling the 511KM1~511KM12 contactors, through the 511RI~511R4 current-limiting resistors and the first equalization bus, voltage and capacity equalization between any target clusters can be achieved.

[0031] For the second equalization bus, multiple battery clusters are connected in parallel to the second equalization bus through current-limiting resistors and equalization switches within a single cluster. The second equalization bus is also connected in series with an AC-DC module or a DC-DC module. By controlling switches S1~S6, S11~S18, S23~S26, AC-DC modules or DC-DC modules, and through current-limiting resistors 511R7~511R13 and 511R17, and the second equalization bus, simultaneous voltage and capacity equalization between any two target clusters can be achieved.

[0032] 511R1~511R4, 511R7~511R13, 511R17: Used to limit current; Switches S1~S6, S11~S18, and S23~S26 are used to control the closing and opening of the circuit. AC-DC module: It can convert AC power to DC power and vice versa; DC-DC module: can control the voltage and current in a DC circuit.

[0033] from Figure 2It can also be seen that the energy storage system includes a control unit, so the voltage and capacity (remaining power) of each battery cluster can be identified through the control unit.

[0034] It should be noted that since each battery cluster contains multiple individual cells, the control unit identifies the total voltage and total capacity of each individual cell in any given battery cluster.

[0035] In addition, the inter-cluster equalization control method provided in the embodiments of this specification is applicable to use when the battery clusters in the energy storage system are in a static operating condition.

[0036] Step 104: When it is determined that voltage balancing and capacity balancing of multiple battery clusters are required based on the voltage value or the capacity value, control the balancing loops formed by the first battery cluster and the second battery cluster in the multiple battery clusters and the first balancing bus to be closed, and control the balancing loops formed by the remaining battery clusters in the multiple battery clusters and the second balancing bus to be closed.

[0037] In one alternative implementation, the voltage imbalance and remaining capacity imbalance of each battery cluster can be determined based on the voltage value and the capacity value. The battery clusters that require voltage and capacity balancing are determined based on the voltage imbalance or the remaining capacity imbalance.

[0038] Specifically, the voltage imbalance of each battery cluster is determined based on the voltage value, and the corresponding formula for calculating the voltage imbalance is as follows: Voltage imbalance = (Target single cluster voltage (V) - Average voltage of all target clusters (V)) / Rated voltage (V) 100% The remaining capacity imbalance of each battery cluster is determined based on its capacity value. The corresponding formula for calculating the capacity imbalance is as follows: Capacity imbalance = (Target single cluster available capacity (Ah) - Average available capacity of all target clusters (Ah)) / Rated capacity (Ah) 100% After determining the voltage imbalance and remaining capacity imbalance of each battery cluster, the battery clusters that need to be balanced in voltage and capacity can be determined based on the voltage imbalance or remaining capacity imbalance. Specifically, battery clusters with a voltage imbalance greater than the first threshold or a remaining capacity imbalance greater than the second threshold can be identified as battery clusters that need to be balanced in voltage and capacity.

[0039] In practical applications, the values ​​of the first and second thresholds can be set according to actual needs, and no restrictions are imposed here.

[0040] After determining the multiple battery clusters that need voltage and capacity balancing based on voltage or capacity imbalance, the system controls the balancing loops formed by the first and second battery clusters and the first balancing bus to close, and controls the balancing loops formed by the remaining battery clusters and the second balancing bus to close.

[0041] In one optional implementation, the first balancing bus includes a positive output bus and a negative output bus, with both ends of each battery cluster connected to the positive output bus and the negative output bus, respectively. The positive output bus and the negative output bus are connected to an energy storage converter. The method further includes: When the energy storage system is in normal operation, one end of the first target battery cluster is connected to the output positive bus via a main positive relay and a first switch, and the other end is connected to the output negative bus via a main negative relay and a second switch, and is charged or discharged through the energy storage converter; When the energy storage system is in an inter-cluster equilibrium state, one end of the first target battery cluster is connected to the positive output bus via a circulating current relay, a circulating current resistor, and the first switch, and the other end is connected to the negative output bus via the main negative relay and the second switch. The first target battery cluster is each of the plurality of battery clusters.

[0042] Furthermore, the first battery cluster, the first circulating current relay, the first circulating current resistor, the first switch, the first main negative relay, and the second switch form a first balancing circuit with the first balancing bus, and the second battery cluster, the second circulating current relay, the second circulating current resistor, the third switch, the second main negative relay, and the fourth switch form a second balancing circuit with the first balancing bus.

[0043] Specifically, such as Figure 2 As shown, the positive output bus of the first equalization bus is BUS+, and the negative output bus is BUS-. Taking the first target battery cluster as battery pack #1 as an example, the main positive relay (first main positive relay) corresponding to battery pack #1 is 511KM2, the corresponding main negative relay (first main negative relay) is 511KM1, the first switch and the second switch are 511QS1, the circulating current relay (first circulating current relay) corresponding to battery pack #1 is 511KM3, and the corresponding circulating current resistor (first circulating current resistor) is 511R1.

[0044] It should be noted that the first switch and the second switch belong to the same switch 511QS1, which means that there are two circuits on one switch housing, one positive circuit and one negative circuit. These two switches are mechanically interlocked and are simultaneously open / closed.

[0045] Battery pack #1, first circulating current relay 511KM3, first circulating current resistor 511R1, first switch and second switch 511QS1, first main negative relay 511KM1, and the first equalization bus form the first equalization circuit. Taking battery pack #4 as the second target battery pack as an example, battery pack #4, second circulating current relay 511KM12, second circulating current resistor 511R4, third switch and fourth switch 511QS4, second main negative relay 511KM10, and the first equalization bus form the second equalization circuit.

[0046] Taking the remaining battery clusters in multiple battery clusters as battery pack #2 and battery pack #3 as an example, battery pack #2, battery pack #3, power conversion modules 511T04 and 511T01, switches S24, S1, S14, S3, S16, S5, S18, S11, S12, S17, S6, S15, S4, S13, S2, S23, and S25, current limiting resistors 511R8, 511R10, 511R12, 511R11, 511R9, 511R7, and 511R17 together with the second equalization bus to form the second equalization circuit.

[0047] It should be noted that controlling the closure of the balancing loops formed by the first and second battery clusters from multiple battery clusters and the first balancing bus is equivalent to performing inter-cluster balancing on the first and second battery clusters through the first balancing bus; controlling the closure of the balancing loops formed by the remaining battery clusters from multiple battery clusters and the second balancing bus is equivalent to performing inter-cluster balancing on each pair of battery clusters within the remaining battery clusters through the second balancing bus. In practical applications, which two battery clusters need to be balanced, or which two battery clusters need to be balanced through which balancing bus, can be determined according to actual needs and is not restricted here.

[0048] Step 106: Charge and discharge the first battery cluster and the second battery cluster through the first equalization bus, and transfer energy between the external power source and the remaining battery clusters through the second equalization bus to equalize the voltage and capacity of the multiple battery clusters.

[0049] In one optional implementation, the energy transfer between the external power source and the remaining battery cluster via the second balancing bus includes: The power conversion module converts the electricity supplied by the external power source and transmits the converted electricity to the remaining battery clusters via the second balancing bus to charge the remaining battery clusters; or... The power conversion module converts the output power of the remaining battery cluster and transmits the converted power to the external power source through the second equalization bus to discharge the remaining battery cluster. Wherein, when the external power source provides AC power, the power conversion module is an AC-DC module; when the external power source provides DC power, the power conversion module is a DC-DC module.

[0050] Specifically, charging and discharging the first and second battery clusters via the first balancing bus is equivalent to achieving voltage and capacity balancing between the first and second battery clusters using the internal power supply of the energy storage system. Charging and discharging the remaining battery clusters via the second balancing bus is equivalent to achieving voltage and / or capacity balancing between each pair of battery clusters within the remaining battery clusters using an external power supply.

[0051] When an external power source provides AC power, energy is transferred between the external power source and the remaining battery clusters via the second balancing bus. Specifically, the AC-DC module converts the AC power supplied by the external power source into DC power, and then transmits the converted DC power to the remaining battery clusters via the second balancing bus to charge the remaining battery clusters. Alternatively, the AC-DC module converts the DC power output from the remaining battery clusters into AC power, and then transmits the converted AC power to the external power source via the second balancing bus to discharge the remaining battery clusters.

[0052] When an external power source provides DC power, energy is transferred between the external power source and the remaining battery clusters via the second equalization bus. Specifically, the DC-DC module converts the DC power supplied by the external power source into voltage, and then transmits the converted DC power to the remaining battery clusters via the second equalization bus to charge the remaining battery clusters. Alternatively, the DC-DC module converts the DC power output from the remaining battery clusters into voltage, and then transmits the converted DC power to the external power source via the second equalization bus to discharge the remaining battery clusters.

[0053] In addition, such as Figure 2 As shown, the energy storage system may also include a third equalization bus, which is located between the first and second equalization buses. The third equalization bus is connected in series with a DC-DC module. By controlling the DC-DC module, voltage and capacity equalization can be achieved between any two target clusters through the third equalization bus.

[0054] In practical applications, when the conditions for balancing total voltage and capacity are met between battery pack #1 and battery pack #4, the battery pack with the higher voltage value between battery pack #1 and battery pack #4 can be identified first, and a bus voltage can be established by connecting them in parallel. Then, the battery pack with the lower total voltage is closed, and the inter-cluster total voltage and capacity balancing between battery pack #1 and battery pack #4 is achieved through the first balancing bus.

[0055] Additionally, when the conditions for balancing total voltage and capacity are met between battery pack #2 and battery pack #3, the inter-cluster balancing between battery pack #2 and battery pack #3 needs to be activated simultaneously with the inter-cluster balancing of battery packs #1 and #4. In this case, the total voltage and capacity balancing between battery pack #2 and battery pack #3 can be achieved through the second or third balancing bus. Specifically, S14, S16, S13, and S15 can be disconnected first, and S3, S4, 511KM6, 511KM9, S1, S2, S5, S6, S24, S25, S11, S12, S23, S18, S17, and S26 can be closed to achieve the inter-cluster total voltage and capacity balancing between battery pack #2 and battery pack #3.

[0056] When balancing the total voltage and capacity between battery pack #2 and battery pack #3 through the second balancing bus, the AC-DC modules connected to the second balancing bus 511T04 and 511T01 can convert the AC power supplied by the external power source into DC power to charge battery pack #2 and battery pack #3 respectively. The charging stops when the target value calculated by the control unit is reached.

[0057] In the embodiments of this specification, the equalization current and equalization time can be controlled by the control unit. After the battery cluster equalization conditions are met, the equalization switch is disconnected by the control unit. The control unit also controls all non-high voltage battery cluster contactors (main positive and main negative relays) and current limiting resistors to sequentially complete the high voltage power-on of all battery clusters according to the power-on process.

[0058] It should be noted that the corresponding equalization circuits in the first equalization bus, the second equalization bus, and the third equalization bus include not only one equalization circuit, but also n equalization circuits; the target battery cluster number for equalization is selected by the control unit according to the calculation results of the strategy algorithm to achieve the highest utilization rate of the equalization system.

[0059] The inter-cluster equalization control method provided in this specification is applied to an energy storage system. The energy storage system includes a first equalization bus, a second equalization bus, and multiple battery clusters. Each battery cluster is connected in parallel to the first equalization bus and also in parallel to the second equalization bus. The second equalization bus is connected to an external power source via a power conversion module. By identifying the voltage and capacity values ​​of each battery cluster, when it is determined that voltage and capacity equalization of multiple battery clusters is required based on the voltage or capacity values, the equalization loops formed by the first and second battery clusters and the first equalization bus are closed, and the equalization loops formed by the remaining battery clusters and the second equalization bus are also closed. The first and second battery clusters are charged and discharged through the first equalization bus, and energy is transferred between the external power source and the remaining battery clusters through the second equalization bus to achieve voltage and capacity equalization of multiple battery clusters. This specification embodiment can simultaneously achieve voltage and capacity equalization between any two clusters through multiple equalization buses and various equalization strategies. This not only helps reduce equalization time and increase applicable scenarios but also effectively improves the equalization capability of the energy storage system, thereby improving the safety of the energy storage system and extending its service life.

[0060] Figure 3 A flowchart of another inter-cluster equalization control method according to an embodiment of this specification is shown. The method is applied to an energy storage system, which includes a first equalization bus, a second equalization bus, and multiple battery clusters. The multiple battery clusters are connected in parallel to the first equalization bus and in parallel to the second equalization bus. The second equalization bus is connected to an external power source through a power conversion module. The method specifically includes the following steps.

[0061] Step 302: Identify the capacity value of each battery cluster.

[0062] Step 304: If it is determined that the second target battery cluster needs to be balanced based on the capacity value, control the balancing loop formed by the second target battery cluster and the second balancing bus to close, wherein the second target battery cluster is one or at least two of the plurality of battery clusters.

[0063] Step 306: Charge and discharge the second target battery cluster through the second equalization bus to equalize the capacity of the second target battery cluster.

[0064] In one optional embodiment, the energy storage system further includes a third balancing bus, the two ends of which are respectively connected to the first balancing bus and the second balancing bus, and are connected in series with the DC-DC module. Accordingly, the method further includes: When it is determined that at least two battery clusters need to be balanced based on the capacity value, the balancing loop formed by the third battery cluster in the at least two battery clusters and the second balancing bus is closed, and the balancing loop formed by the remaining battery clusters in the at least two battery clusters and the third balancing bus is closed respectively. The third battery cluster is charged and discharged through the second equalization bus, and the remaining battery clusters in the at least two battery clusters are charged and discharged through the third equalization bus to achieve capacity equalization of the at least two battery clusters.

[0065] In one alternative implementation, the energy storage system further includes a control unit; Accordingly, the method further includes: The control unit controls the balancing current and balancing time of the second target battery cluster. If the conditions for battery cluster balancing to be completed are met, the balancing switch in the balancing circuit is disconnected by the control unit. The control unit controls the closing of the main positive relay and main negative relay of the second target battery cluster to enter the normal charging and discharging mode.

[0066] The embodiment of this specification provides another inter-cluster equalization control method, which is applicable to use when battery clusters in an energy storage system are in charging or discharging conditions.

[0067] When the battery clusters in the energy storage system are in charging mode, the control unit identifies the capacity difference of each battery cluster. The control unit determines whether any battery cluster needs to be balanced based on the unbalanced remaining capacity of each battery cluster. When multiple clusters in the battery stack need to be balanced simultaneously during charging, for example, when battery pack #1 needs to be balanced, S1, S2, S23, S26, 511KM1, and 511KM2 are first disconnected, and then S24, S25, and 511KM3 are closed. Other clusters that do not need to be balanced close the main positive and main negative contactors (relays). The charging capacity of battery pack #1 is balanced using the AC-DC module and the second balancing bus of 511T04. For example, while battery pack #1 is being balanced, battery pack #4 also needs to be balanced. First, disconnect S5, S6, S17, S18, 511KM10, and 511KM11, then close S11, S12, and 511KM12. The charging capacity of battery pack #4 is then balanced using the AC-DC module and the second balancing bus of 511T01. Alternatively, the charging capacity of battery pack #4 can be balanced using the DC-DC module and the third balancing bus.

[0068] The control unit sets the target state of charge (SOC) for battery cluster balancing, as well as the main circuit charging current and the balancing circuit charging current, based on the battery cluster capacity differences and the balancing battery adjustment capability. After determining that the battery cluster balancing conditions are met, the control unit controls the balancing switch to open and the main positive contactor and main negative contactor to enter normal charging mode.

[0069] Wherein, the target balancing capacity (Ah) = (Rated power of balancing bus (kW) / Voltage of balancing circuit (V)) Equilibrium time (h).

[0070] The schematic diagram of the flow direction of charging energy in an energy storage system provided in the embodiments of this specification is shown below. Figure 4 As shown. From Figure 4 It can be seen that when performing capacity balancing on the battery clusters in the energy storage system under charging conditions, the charging energy flow in the energy storage system is from the energy storage converter PCS to the battery clusters.

[0071] In addition, when the battery clusters in the energy storage system are in discharge mode, the control unit identifies the capacity difference of each battery cluster; the control unit determines whether any battery cluster needs to be balanced based on the remaining capacity imbalance of each battery cluster; when it is determined that multiple clusters in the battery stack need to be balanced at the same time under discharge mode, for example, when battery pack #1 needs to be balanced, S1, S2, S23, S26, 511KM1, and 511KM2 are first disconnected, and then S24, S25, and 511KM3 are closed, and the main positive and main negative contactors (relays) of other clusters that do not need to be balanced are closed. The discharge capacity of battery pack #1 is balanced using the AC-DC module and the second balancing bus of 511T04. For example, while battery pack #1 is being balanced, battery pack #4 also needs to be balanced. First, disconnect S5, S6, S17, S18, 511KM10, and 511KM11, then close S11, S12, and 511KM12. The discharge capacity of battery pack #4 is then balanced using the AC-DC module and the second balancing bus of 511T01. Alternatively, the discharge capacity of battery pack #4 can be balanced using the DC-DC module and the third balancing bus.

[0072] The control unit sets the target state of charge (SOC) for battery cluster balancing, as well as the main circuit discharge current and the balancing circuit discharge current, based on the battery cluster capacity differences and the balancing battery adjustment capability. After determining that the battery cluster balancing conditions are met, the control unit controls the balancing switch to open and the main positive contactor and main negative contactor to enter the normal discharge mode.

[0073] The schematic diagram of the discharge energy flow direction in an energy storage system provided in the embodiments of this specification is shown below. Figure 5 As shown. From Figure 5It can be seen that when the battery clusters in the energy storage system are balanced under discharge conditions, the discharge energy flow in the energy storage system flows from the battery clusters to the energy storage converter PCS.

[0074] The embodiments in this specification can simultaneously achieve capacity balancing between any clusters through multiple balancing buses and various balancing strategies. This not only helps to reduce balancing time and increase applicable scenarios, but also effectively improves the balancing capability of the energy storage system, thereby improving the safety of the energy storage system and extending its service life.

[0075] It should be noted that the other inter-cluster equalization control method provided in the embodiments of this specification is based on the same concept as the inter-cluster equalization control method in the foregoing embodiments. The difference is that the other inter-cluster equalization control method provided in the embodiments of this specification is applicable to battery clusters in energy storage systems when they are in charging or discharging conditions, and only performs capacity equalization on battery clusters. For details not described in detail in the technical solution of the other inter-cluster equalization control method provided in the embodiments of this specification, please refer to the description of the technical solution of the above-mentioned inter-cluster equalization control method.

[0076] Corresponding to the above method embodiment, this specification also provides an embodiment of an inter-cluster equalization control device. Figure 6 This specification illustrates a schematic diagram of an inter-cluster equalization control device according to an embodiment of the present specification. The device is applied to an energy storage system, which includes a first equalization bus, a second equalization bus, and multiple battery clusters. The multiple battery clusters are connected in parallel to the first equalization bus and in parallel to the second equalization bus. The second equalization bus is connected to an external power source via a power conversion module. Figure 6 As shown, the device includes: The first identification module 602 is configured to identify the voltage and capacity values ​​of each battery cluster. The first control module 604 is configured to, when it is determined that voltage balancing and capacity balancing of multiple battery clusters need to be performed based on the voltage value or the capacity value, control the balancing loops formed by the first battery cluster and the second battery cluster in the multiple battery clusters respectively with the first balancing bus to close, and control the balancing loops formed by the remaining battery clusters in the multiple battery clusters respectively with the second balancing bus to close. The first processing module 606 is configured to charge and discharge the first battery cluster and the second battery cluster through the first balancing bus, and to transfer energy between the external power source and the remaining battery clusters through the second balancing bus, so as to balance the voltage and capacity of the multiple battery clusters.

[0077] Optionally, the first balancing bus includes a positive output bus and a negative output bus, with each battery cluster connected to the positive output bus and the negative output bus at both ends, respectively. The positive output bus and the negative output bus are connected to an energy storage converter. The device further includes a first control module configured to: When the energy storage system is in normal operation, one end of the first target battery cluster is connected to the output positive bus via a main positive relay and a first switch, and the other end is connected to the output negative bus via a main negative relay and a second switch, and is charged or discharged through the energy storage converter; When the energy storage system is in an inter-cluster equilibrium state, one end of the first target battery cluster is connected to the positive output bus via a circulating current relay, a circulating current resistor, and the first switch, and the other end is connected to the negative output bus via the main negative relay and the second switch. The first target battery cluster is each of the plurality of battery clusters.

[0078] Optionally, the first battery cluster, the first circulating current relay, the first circulating current resistor, the first switch, the first main negative relay, and the second switch form a first balancing circuit with the first balancing bus, and the second battery cluster, the second circulating current relay, the second circulating current resistor, the third switch, the second main negative relay, and the fourth switch form a second balancing circuit with the first balancing bus.

[0079] Optionally, the first control module is further configured to: The voltage imbalance and remaining capacity imbalance of each battery cluster are determined based on the voltage value and the capacity value. The battery clusters that require voltage and capacity balancing are determined based on the voltage imbalance or the remaining capacity imbalance.

[0080] Optionally, the first processing module 606 is further configured to: The power conversion module converts the electricity supplied by the external power source and transmits the converted electricity to the remaining battery clusters via the second balancing bus to charge the remaining battery clusters; or... The power conversion module converts the output power of the remaining battery cluster and transmits the converted power to the external power source through the second equalization bus to discharge the remaining battery cluster. Wherein, when the external power source provides AC power, the power conversion module is an AC-DC module; when the external power source provides DC power, the power conversion module is a DC-DC module.

[0081] The above is a schematic scheme of an inter-cluster equalization control device according to this embodiment. It should be noted that the technical solution of this inter-cluster equalization control device and the technical solution of the inter-cluster equalization control method described above belong to the same concept. For details not described in detail in the technical solution of this inter-cluster equalization control device, please refer to the description of the technical solution of the inter-cluster equalization control method described above.

[0082] Corresponding to the other method embodiment described above, this specification also provides another embodiment of the inter-cluster equalization control device. Figure 7 This specification illustrates a schematic diagram of another inter-cluster equalization control device according to an embodiment. This device is applied to an energy storage system, which includes a first equalization bus, a second equalization bus, and multiple battery clusters. The multiple battery clusters are connected in parallel to the first equalization bus and in parallel to the second equalization bus. The second equalization bus is connected to an external power source via a power conversion module, such as... Figure 7 As shown, the device includes: The second identification module 702 is configured to identify the capacity value of each battery cluster; The second control module 704 is configured to control the balancing loop formed by the second target battery cluster and the second balancing bus to close when it is determined that the second target battery cluster needs to be balanced based on the capacity value, wherein the second target battery cluster is one or at least two of the plurality of battery clusters. The second processing module 706 is configured to perform charge and discharge processing on the second target battery cluster through the second equalization bus to perform capacity equalization on the second target battery cluster.

[0083] Optionally, the energy storage system further includes a third balancing bus, the two ends of which are respectively connected to the first balancing bus and the second balancing bus, and are connected in series with the DC-DC module; Accordingly, the device further includes a second control module configured to: When it is determined that at least two battery clusters need to be balanced based on the capacity value, the balancing loop formed by the third battery cluster in the at least two battery clusters and the second balancing bus is closed, and the balancing loop formed by the remaining battery clusters in the at least two battery clusters and the third balancing bus is closed respectively. The third battery cluster is charged and discharged through the second equalization bus, and the remaining battery clusters in the at least two battery clusters are charged and discharged through the third equalization bus to achieve capacity equalization of the at least two battery clusters.

[0084] Optionally, the energy storage system further includes a control unit; Accordingly, the second control module is also configured as follows: The control unit controls the balancing current and balancing time of the second target battery cluster. If the conditions for battery cluster balancing to be completed are met, the balancing switch in the balancing circuit is disconnected by the control unit. The control unit controls the closing of the main positive relay and main negative relay of the second target battery cluster to enter the normal charging and discharging mode.

[0085] The above is an illustrative scheme of another inter-cluster equalization control device in this embodiment. It should be noted that the technical solution of this inter-cluster equalization control device and the technical solution of the other inter-cluster equalization control method described above belong to the same concept. For details not described in detail in the technical solution of this inter-cluster equalization control device, please refer to the description of the technical solution of the other inter-cluster equalization control method described above.

[0086] Figure 8 A structural block diagram of a computing device 800 according to one embodiment of this specification is shown. The components of the computing device 800 include, but are not limited to, a memory 810 and a processor 820. The processor 820 is connected to the memory 810 via a bus 830, and a database 850 is used to store data.

[0087] The computing device 800 also includes an access device 840, which enables the computing device 800 to communicate via one or more networks 860. Examples of these networks include a Public Switched Telephone Network (PSTN), a Local Area Network (LAN), a Wide Area Network (WAN), a Personal Area Network (PAN), or a combination of communication networks such as the Internet. The access device 840 may include one or more of any type of wired or wireless network interface (e.g., a Network Interface Card (NIC)), such as an IEEE 802.11 Wireless Local Area Network (WLAN) interface, a Wi-MAX interface, an Ethernet interface, a Universal Serial Bus (USB) interface, a cellular network interface, a Bluetooth interface, a Near Field Communication (NFC) interface, and so on.

[0088] In one embodiment of this specification, the above-described components of the computing device 800 and Figure 8 Other components, not shown, can also be connected to each other, for example, via a bus. It should be understood that... Figure 8 The block diagram of the computing device shown is for illustrative purposes only and is not intended to limit the scope of this specification. Those skilled in the art can add or replace other components as needed.

[0089] The computing device 800 can be any type of stationary or mobile computing device, including mobile computers or mobile computing devices (e.g., tablet computers, personal digital assistants, laptop computers, notebook computers, netbooks, etc.), mobile phones (e.g., smartphones), wearable computing devices (e.g., smartwatches, smart glasses, etc.) or other types of mobile devices, or stationary computing devices such as desktop computers or PCs. The computing device 800 can also be a mobile or stationary server.

[0090] The processor 820 is used to execute the following computer-executable instructions, which, when executed by the processor, implement the steps of the above-described inter-cluster equalization control method.

[0091] The above is a schematic representation of a computing device according to this embodiment. It should be noted that the technical solution of this computing device and the technical solution of the inter-cluster load balancing control method described above belong to the same concept. Details not described in detail in the technical solution of the computing device can be found in the description of the technical solution of the inter-cluster load balancing control method described above.

[0092] An embodiment of this specification also provides a computer-readable storage medium storing computer-executable instructions that, when executed by a processor, implement the steps of the above-described inter-cluster equalization control method.

[0093] The above is an illustrative scheme of a computer-readable storage medium according to this embodiment. It should be noted that the technical solution of this storage medium and the technical solution of the inter-cluster leveling control method described above belong to the same concept. For details not described in detail in the technical solution of the storage medium, please refer to the description of the technical solution of the inter-cluster leveling control method described above.

[0094] An embodiment of this specification also provides a computer program, wherein when the computer program is executed in a computer, it causes the computer to perform the steps of the above-described inter-cluster balance control method.

[0095] The above is an illustrative scheme of a computer program according to this embodiment. It should be noted that the technical solution of this computer program and the technical solution of the inter-cluster equalization control method described above belong to the same concept. For details not described in detail in the technical solution of the computer program, please refer to the description of the technical solution of the inter-cluster equalization control method described above.

[0096] The foregoing has described specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0097] The computer instructions include computer program code, which may be in the form of source code, object code, executable file, or certain intermediate forms. The computer-readable medium may include any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium may be appropriately added to or subtracted according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media may not include electrical carrier signals and telecommunication signals.

[0098] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that the embodiments in this specification are not limited to the described order of actions, because according to the embodiments in this specification, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in this specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the embodiments in this specification.

[0099] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0100] The preferred embodiments disclosed above are merely illustrative of this specification. The optional embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the embodiments described herein. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the embodiments, thereby enabling those skilled in the art to better understand and utilize this specification. This specification is limited only by the claims and their full scope and equivalents.

Claims

1. A cluster-to-cluster equalization control method applied to an energy storage system, the energy storage system comprising a first equalization bus, a second equalization bus, and multiple battery clusters, the multiple battery clusters being connected in parallel to the first equalization bus and in parallel to the second equalization bus, the second equalization bus being connected to an external power source via a power conversion module, the method comprising: Identify the voltage and capacity values ​​of each battery cluster; When it is determined that voltage balancing and capacity balancing of multiple battery clusters are required based on the voltage value or the capacity value, the balancing loops formed by the first battery cluster and the second battery cluster in the multiple battery clusters and the first balancing bus are controlled to close, and the balancing loops formed by the remaining battery clusters in the multiple battery clusters and the second balancing bus are controlled to close. The first battery cluster and the second battery cluster are charged and discharged through the first equalization bus, and energy is transferred between the external power source and the remaining battery clusters through the second equalization bus to balance the voltage and capacity of the multiple battery clusters.

2. The inter-cluster equalization control method according to claim 1, wherein the first equalization bus includes a positive output bus and a negative output bus, both ends of each battery cluster are respectively connected to the positive output bus and the negative output bus, the positive output bus and the negative output bus are connected to an energy storage converter, and the method further includes: When the energy storage system is in normal operation, one end of the first target battery cluster is connected to the output positive bus via a main positive relay and a first switch, and the other end is connected to the output negative bus via a main negative relay and a second switch, and is charged or discharged through the energy storage converter; When the energy storage system is in an inter-cluster equilibrium state, one end of the first target battery cluster is connected to the positive output bus via a circulating current relay, a circulating current resistor, and the first switch, and the other end is connected to the negative output bus via the main negative relay and the second switch. The first target battery cluster is each of the plurality of battery clusters.

3. The inter-cluster equalization control method according to claim 2, wherein the first battery cluster, the first circulating current relay, the first circulating current resistor, the first switch, the first main negative relay, and the second switch form a first equalization circuit with the first equalization bus, and the second battery cluster, the second circulating current relay, the second circulating current resistor, the third switch, the second main negative relay, and the fourth switch form a second equalization circuit with the first equalization bus.

4. The inter-cluster balance control method according to claim 1 further includes: The voltage imbalance and remaining capacity imbalance of each battery cluster are determined based on the voltage value and the capacity value. The battery clusters that require voltage and capacity balancing are determined based on the voltage imbalance or the remaining capacity imbalance.

5. The inter-cluster equalization control method according to claim 1, wherein the energy transfer between the external power source and the remaining battery cluster via the second equalization bus comprises: The power conversion module converts the electricity supplied by the external power source and transmits the converted electricity to the remaining battery clusters via the second balancing bus to charge the remaining battery clusters; or... The power conversion module converts the output power of the remaining battery cluster and transmits the converted power to the external power source through the second equalization bus to discharge the remaining battery cluster. Wherein, when the external power source provides AC power, the power conversion module is an AC-DC module; when the external power source provides DC power, the power conversion module is a DC-DC module.

6. A cluster balancing control method applied to an energy storage system, the energy storage system comprising a first balancing bus, a second balancing bus, and multiple battery clusters, the multiple battery clusters being connected in parallel to the first balancing bus and in parallel to the second balancing bus, the second balancing bus being connected to an external power source via a power conversion module, the method comprising: Identify the capacity value of each battery cluster; When it is determined that capacity balancing of the second target battery cluster is required based on the capacity value, the balancing loop formed by the second target battery cluster and the second balancing bus is controlled to close, wherein the second target battery cluster is one or at least two of the plurality of battery clusters; The second target battery cluster is charged and discharged through the second equalization bus to equalize its capacity.

7. The inter-cluster equalization control method according to claim 6, wherein the energy storage system further includes a third equalization bus, the two ends of which are respectively connected to the first equalization bus and the second equalization bus, and are connected in series with a DC-DC module; Accordingly, the method further includes: When it is determined that at least two battery clusters need to be balanced based on the capacity value, the balancing loop formed by the third battery cluster in the at least two battery clusters and the second balancing bus is closed, and the balancing loop formed by the remaining battery clusters in the at least two battery clusters and the third balancing bus is closed respectively. The third battery cluster is charged and discharged through the second equalization bus, and the remaining battery clusters in the at least two battery clusters are charged and discharged through the third equalization bus to achieve capacity equalization of the at least two battery clusters.

8. The inter-cluster equalization control method according to claim 6, wherein the energy storage system further includes a control unit; Accordingly, the method further includes: The control unit controls the balancing current and balancing time of the second target battery cluster. If the conditions for battery cluster balancing to be completed are met, the balancing switch in the balancing circuit is disconnected by the control unit. The control unit controls the closing of the main positive relay and main negative relay of the second target battery cluster to enter the normal charging and discharging mode.

9. An inter-cluster equalization control device, applied to an energy storage system, the energy storage system including a first equalization bus, a second equalization bus, and multiple battery clusters, the multiple battery clusters being connected in parallel to the first equalization bus and in parallel to the second equalization bus, the second equalization bus being connected to an external power source through a power conversion module, the device comprising: The first identification module is configured to identify the voltage and capacity values ​​of each battery cluster. The first control module is configured to, when it is determined that voltage balancing and capacity balancing of multiple battery clusters need to be performed based on the voltage value or the capacity value, control the balancing loops formed by the first battery cluster and the second battery cluster in the multiple battery clusters respectively with the first balancing bus to close, and control the balancing loops formed by the remaining battery clusters in the multiple battery clusters respectively with the second balancing bus to close. The first processing module is configured to charge and discharge the first battery cluster and the second battery cluster through the first balancing bus, and to transfer energy between the external power source and the remaining battery clusters through the second balancing bus, so as to balance the voltage and capacity of the multiple battery clusters.

10. An inter-cluster equalization control device, applied to an energy storage system, the energy storage system including a first equalization bus, a second equalization bus, and multiple battery clusters, the multiple battery clusters being connected in parallel to the first equalization bus and in parallel to the second equalization bus, the second equalization bus being connected to an external power source through a power conversion module, the device comprising: The second identification module is configured to identify the capacity value of each battery cluster; The second control module is configured to control the balancing loop formed by the second target battery cluster and the second balancing bus to close when it is determined that the second target battery cluster needs to be balanced based on the capacity value, wherein the second target battery cluster is one or at least two of the plurality of battery clusters. The second processing module is configured to perform charge and discharge processing on the second target battery cluster through the second equalization bus to equalize the capacity of the second target battery cluster.

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