Battery cluster-level equalization management methods, controllers, storage media, and energy storage systems

Abstract

This invention provides a battery cluster-level equalization management method, controller, storage medium, and energy storage system. The energy storage system using this method connects a converter module in parallel at the switching module of each battery cluster. This allows the system to determine whether any battery clusters have unbalanced charge levels based on their electrical parameters. If an unbalanced battery cluster is found, the corresponding switching module disconnects the cluster from the DC bus and activates the corresponding converter module, enabling the cluster to achieve charge equalization through the three-phase power distribution. This method allows for high-power equalization of some battery clusters without affecting the charging and discharging of the energy storage system, thus achieving rapid equalization between battery clusters.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and in particular to a battery cluster-level equalization management method, controller, storage medium, and energy storage system. Background Technology

[0002] A battery cluster consists of multiple batteries connected in series or parallel. Series connection increases the battery terminal voltage, while parallel connection increases battery capacity. Each battery cluster is connected to an energy storage converter via a switching module, which in turn connects to the power grid, forming an energy storage system. The battery cluster, as a key component for storing and releasing electrical energy, is a critical piece of equipment in the energy storage system and directly affects its safe and stable operation.

[0003] In the later stages of operation, traditional energy storage systems experience widening inconsistencies between individual cells. Premature overvoltage (triggering charge inactivity) or undervoltage (triggering discharge inactivity) in a single cell can lead to a system-wide shutdown, reducing the usable capacity of the entire battery pack. While existing cell control units employ both active and passive balancing methods to address these differences, active balancing, where each battery cluster is connected to the energy storage converter via a DC-DC converter and its charging / discharging and balancing management, requires a high-power DC-DC converter for each cluster, placing stringent demands on device specifications. Passive balancing, primarily addressing cell-to-cell inconsistencies, suffers from insufficient balancing power. Over long-term operation, the passive balancing capability fails to compensate for cell degradation, leading to a gradual widening of inconsistencies between cells. Summary of the Invention

[0004] This invention provides a battery cluster-level equalization management method, controller, storage medium, and energy storage system to address the problem of ever-increasing differences between battery clusters in the prior art.

[0005] In a first aspect, embodiments of the present invention provide a battery cluster-level equalization management method applied to an energy storage system. The energy storage system includes an energy storage converter, multiple battery clusters, and a high-voltage box corresponding to each battery cluster. The high-voltage box includes a switching module and a converter module. Each battery cluster is connected to the first terminal of the corresponding switching module and the first terminal of the converter module. The second terminal of each switching module is connected to the energy storage converter via a DC bus. The second terminal of each converter module is connected to the three-phase power distribution terminal of the energy storage system. The method includes:

[0006] Obtain the electrical parameters of each battery cluster, and determine whether there are battery clusters with uneven power based on the electrical parameters of each battery cluster;

[0007] If there are battery clusters with unbalanced power, the corresponding switch module of the battery cluster will disconnect the battery cluster from the DC bus and start the corresponding converter module of the battery cluster so that the battery cluster can be balanced through the three-phase power distribution terminal.

[0008] In a second aspect, embodiments of the present invention provide a controller, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the battery cluster-level equalization management method as described in any possible implementation of the first aspect above.

[0009] Thirdly, embodiments of the present invention provide a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the battery cluster-level equalization management method as described in any possible implementation of the first aspect above.

[0010] Fourthly, this application provides an energy storage system, including the controller described above.

[0011] This invention provides a battery cluster-level equalization management method, controller, storage medium, and energy storage system. The method is applied to an energy storage system in which a converter module is connected in parallel at the switching module of each battery cluster's high-voltage box. This converter module can determine whether there are battery clusters with uneven charge levels based on the electrical parameters of each cluster. If an unevenly charged battery cluster exists, the corresponding switching module is controlled to disconnect the battery cluster from the DC bus, and the corresponding converter module is activated to achieve charge equalization through the three-phase power distribution terminal. This method enables high-power equalization management of battery clusters when there is an imbalance between them, thereby accelerating the equalization management speed and preventing the continuous increase of differences between battery clusters. Furthermore, the converter module provided in this application only needs to equalize the charge difference between battery clusters and does not need to manage the full charge and discharge range of the battery cluster. Therefore, the requirements for the power and voltage withstand capability of the current module are not high, thus saving on device and heat dissipation costs. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the energy storage system provided in an embodiment of the present invention;

[0014] Figure 2 This is a circuit diagram of the converter module provided in an embodiment of the present invention;

[0015] Figure 3 This is a flowchart illustrating the implementation of the battery cluster-level equalization management method provided in this embodiment of the invention.

[0016] Figure 4 This is a schematic diagram of the battery cluster-level equalization management device provided in an embodiment of the present invention;

[0017] Figure 5 This is a schematic diagram of the controller provided in an embodiment of the present invention. Detailed Implementation

[0018] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0019] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments will be described below in conjunction with the accompanying drawings.

[0020] Figure 1 This diagram illustrates an application scenario of the battery cluster-level equalization management method provided in this embodiment of the invention. The method is applied to energy storage systems, such as... Figure 1 As shown, the energy storage system includes a power conversion system (PCS), multiple battery clusters, and a high-voltage box corresponding to each battery cluster. The high-voltage box includes a switch module and a converter module (ACDC). Each battery cluster is connected to the first terminal of the corresponding switch module and the first terminal of the converter module (ACDC). The second terminal of each switch module is connected to the power conversion system (PCS) via a DC bus. The second terminal of each converter module (ACDC) is connected to the three-phase power distribution terminal of the energy storage system.

[0021] In this embodiment, as Figure 1 As shown, the energy storage system includes multiple battery clusters, each of which includes multiple batteries. The batteries are connected in series and then connected to the DC bus of the energy storage converter through a switching module. The AC terminal of the energy storage converter PCS is connected to the power grid.

[0022] Specifically, when the battery cluster is performing normal charging and discharging tasks, the switching module controls the on and off of the battery cluster. When the battery cluster is undergoing equalization management, the switching module is turned off and the converter module is turned on, thereby balancing the power of the battery cluster through the converter module.

[0023] Specifically, the converter module is used to rectify the AC power from the three-phase distribution terminal into DC power and supply it to the battery pack, or to invert the DC power from the battery pack into AC power and supply it to the three-phase distribution terminal. The three-phase distribution terminal can be a station service distribution terminal, which is connected to the power grid via a transformer. In addition, the three-phase distribution terminal can also be a three-phase power supply terminal for other external applications.

[0024] In one possible implementation, the converter module includes a rectifier unit 101 and a DC-DC unit 103;

[0025] The AC terminal of the rectifier unit is connected to the power distribution terminal, the DC terminal of the rectifier unit is connected to the first terminal of the DC-DC unit, and the second terminal of the DC-DC unit is connected to the corresponding battery cluster.

[0026] In one possible implementation, such as Figure 2 As shown, the rectifier unit 101 includes a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, and a sixth diode D6;

[0027] The cathodes of the first diode D1, the second diode D2, and the third diode D3 are connected to the positive terminal of the DC rectifier unit. The positive terminal of the first diode D1 is connected to phase A of the three-phase distribution terminal and the cathode of the fourth diode D4. The positive terminal of the second diode D2 is connected to phase B of the three-phase distribution terminal and the cathode of the fifth diode D5. The positive terminal of the third diode D3 is connected to phase C of the three-phase distribution terminal and the cathode of the sixth diode D6. The positive terminals of the fourth diode D4, the fifth diode D5, and the sixth diode D6 are connected to the negative terminal of the DC rectifier unit.

[0028] In one possible implementation, such as Figure 2 As shown, the DC-DC unit 103 includes a first capacitor C2, a second capacitor C4, a first inductor L1, a first switching unit Q1, a second switching unit Q2, a third switching unit Q3, and a fourth switching unit Q4.

[0029] The first terminal of the first inductor L1 is connected to the positive terminal of the first terminal of the DC-DC unit. The second terminal of the first inductor L1 is connected to the first terminal of the first switching unit Q1, the first terminal of the third switching unit Q3, and the first terminal of the first capacitor C2. The second terminal of the first switching unit Q1 is connected to the first terminal of the second switching unit Q2. The second terminal of the second switching unit Q2 and the second terminal of the first capacitor C2 are connected to the negative terminal of the DC-DC unit. The second terminal of the third switching unit Q3 is connected to the first terminal of the fourth switching unit Q4. The second terminal of the fourth switching unit Q4 is connected to the positive terminal of the second terminal of the DC-DC unit. The first terminal of the second capacitor C4 is connected to the first terminal of the second switching unit Q2. The second terminal of the second capacitor C4 is connected to the second terminal of the third switching unit Q3.

[0030] In one possible implementation, such as Figure 2 As shown, the converter module also includes a buffer unit 102;

[0031] The buffer unit includes a first switch, a seventh diode D7, a second resistor R2, a buffer switch K_f, and a fuse fu;

[0032] The first switch is connected in series between the positive DC terminal of the sorting unit and the positive first terminal of the DCDC unit. The first terminal of the first switch, the anode of the seventh diode D7, the cathode of the seventh diode D7, the first terminal of the buffer switch K_f, the second terminal of the buffer switch K_f, the first terminal of the second resistor R2, the second terminal of the second resistor R2, the first terminal fu of the fuse, the second terminal fu of the fuse, and the second terminal of the first switch are connected in sequence to form a buffer circuit.

[0033] Specifically, Figure 2 The circuit structure of the given converter module enables the three-phase power distribution terminal to charge each battery cluster to achieve power balancing, thereby improving the battery cluster balancing efficiency.

[0034] In one possible implementation, the converter module further includes a first filtering unit;

[0035] The first end of the first filter unit is connected to the DC end of the rectifier unit, and the second end of the first filter module is connected to the first end of the DC-DC unit.

[0036] Specifically, the first filtering unit is an EMI filter.

[0037] In one possible implementation, the converter module further includes a second filtering unit;

[0038] The first end of the second filter unit is connected to the second end of the DCDC unit, and the second end of the second filter module is connected to the corresponding battery cluster.

[0039] Specifically, the second filtering unit is an EMI filter.

[0040] In one possible implementation, the converter module includes a fully controlled rectifier circuit for converting between the AC power from the three-phase distribution terminal and the DC power output from the battery cluster.

[0041] In one possible implementation, the switch module includes a main contactor KM1-1; a first terminal of the main contactor KM1-1 is connected to the battery cluster, and a second terminal of the main contactor KM1-1 is connected to the DC bus.

[0042] Specifically, the controller is used to disconnect the main contactor of the switching module corresponding to the battery cluster when an uneven charge level is detected.

[0043] Specifically, such as Figure 1 As shown, the high-voltage box A11 includes a main contactor KM1-1, a secondary contactor KM1-3, a disconnecting switch QS1, a first resistor R1, and a converter module ACCDC1. The first terminals of the main contactor KM1-1, the secondary contactor KM1-3, and the converter module ACCDC1 are all connected to the corresponding battery clusters. The second terminal of the secondary contactor KM1-3 is connected to the first terminal of the first resistor R1. The second terminals of the first resistor R1 and the main contactor KM1-1 are all connected to one terminal of the disconnecting switch QS1. The other terminal of the disconnecting switch QS1 is connected to the DC bus. The second terminal of the converter module ACCDC1 is connected to the three-phase power distribution terminal.

[0044] In one possible implementation, the controller includes a main control unit, a cluster-level control unit corresponding to each battery cluster, and a battery control unit corresponding to each battery in the battery cluster;

[0045] The main control unit is communicatively connected to the energy storage converter and each cluster-level control unit. The cluster-level control unit is communicatively connected to the switching module, converter module and battery control unit of each battery in the corresponding battery cluster. The battery control unit is communicatively connected to the corresponding battery.

[0046] In one possible implementation, the rectifier unit is a bidirectional synchronous rectifier circuit, and correspondingly, the DC-DC unit is a bidirectional DC-DC circuit. By setting the bidirectional synchronous rectifier circuit and the bidirectional DC-DC circuit, the power balance of unbalanced battery clusters can be achieved by charging the battery clusters from the three-phase power distribution terminal or discharging them from the battery clusters to the three-phase power distribution terminal.

[0047] To achieve online equalization management of battery clusters, this embodiment adds a converter module to each battery cluster. The first end of the converter module is connected to the battery cluster, and the second end of the converter module is connected to the three-phase power distribution terminal. Since the converter module requires a certain voltage difference between the DC bus and the battery to operate, online equalization is adopted. Due to the voltage difference issue, power cannot be directly drawn from the DC bus of the energy storage converter. Therefore, this application draws power from the power distribution terminal, which can achieve equalization between battery clusters and avoid interference of the equalization process on the energy storage charging and discharging process. It is suitable for scenarios where the energy storage system is not allowed to charge and discharge the grid, and has a wider range of applications.

[0048] See Figure 3 The flowchart illustrating the implementation of the battery cluster-level equalization management method provided in this embodiment of the invention is described in detail below:

[0049] S101: Obtain the electrical parameters of each battery cluster, and determine whether there are battery clusters with uneven power based on the electrical parameters of each battery cluster.

[0050] In this embodiment, the executing entity can be the controller of the energy storage system. The controller can be the main control unit of the energy storage system or a separate cluster-level optimization controller. This embodiment will use the main control unit as an example for subsequent explanation.

[0051] Specifically, electrical parameters include, but are not limited to, total battery cluster voltage, battery voltage, and battery cluster SOC (State of Charge). The battery voltage is acquired by the battery control unit and sent to the cluster-level control unit. The cluster-level control unit acquires the total battery cluster voltage based on the battery voltage of each cell within the cluster and sends the total battery cluster voltage, the voltage of each cell within the corresponding cluster, and the SOC value of the cluster to the main control unit. The main control unit determines whether there are battery clusters with uneven charge levels based on the total battery cluster voltage and / or SOC value of each cluster.

[0052] In one possible implementation, the electrical parameters include battery voltage and SOC value; the specific implementation process of S101 includes:

[0053] The difference between the current SOC value and the SOC reference value of each battery cluster is calculated to obtain the corresponding power deviation value of each battery cluster. Among them, when the battery clusters are charged for power balancing, the SOC reference value is the maximum SOC value of all battery clusters in the energy storage system; when the battery clusters are discharged for power balancing, the SOC reference value is the minimum SOC value of all battery clusters in the energy storage system.

[0054] If the power deviation of a battery cluster is greater than a preset deviation threshold, and the voltage difference between batteries within the battery cluster exceeds a preset voltage threshold, then the power of the battery cluster is determined to be unbalanced.

[0055] In this embodiment, if the power deviation of a battery cluster is greater than a preset deviation threshold, the difference between the maximum and minimum battery voltages of all batteries in the battery cluster is calculated. If the difference between the maximum and minimum battery voltages of all batteries in the battery cluster exceeds a preset voltage threshold, the power of the battery cluster is determined to be unbalanced.

[0056] Specifically, using the method described above for determining unbalanced battery clusters based on the maximum SOC value, after identifying the unbalanced battery clusters, they need to be charged to achieve charge balance between these clusters and other battery clusters. During the charging process, when performing charge balance detection, the SOC value of each battery cluster is the maximum SOC value among the SOC values ​​of all cells within that cluster. Alternatively, using the method described above for determining unbalanced battery clusters based on the minimum SOC value, after identifying the unbalanced battery clusters, they need to be discharged to achieve charge balance between these clusters and other battery clusters. During the discharging process, when performing charge balance detection, the SOC value of each battery cluster is the minimum SOC value among the SOC values ​​of all cells within that cluster.

[0057] For example, the power deviation value can be 1% to 10%, preferably 5%. The preset voltage threshold can be 0.1V to 0.6V, preferably 0.35V.

[0058] S102: If there are battery clusters with unbalanced power, control the switch module corresponding to the battery cluster to disconnect the battery cluster from the DC bus and start the converter module corresponding to the battery cluster so that the battery cluster can be balanced through the three-phase power distribution terminal.

[0059] In this embodiment, when a battery cluster with uneven power is detected, a switch module disconnect command and a converter module start command are sent to the corresponding cluster-level control unit. After receiving the switch module disconnect command and the converter module start command, the cluster-level control unit first disconnects the main contactor in the switch module, and then controls the converter module corresponding to the battery cluster to start. The converter module is used to charge and discharge the battery cluster to achieve power balance of the battery cluster.

[0060] The above method can perform high-power equalization management of battery clusters when there is an imbalance between battery clusters, thereby accelerating the equalization management speed of battery clusters and avoiding the continuous increase of differences between battery clusters. Moreover, the current converter provided in this application only needs to equalize the difference in charge between battery clusters and does not need to perform full-range charge and discharge management of battery clusters. Therefore, the requirements for the power and voltage withstand capability of the current module are not high, thereby saving device cost and heat dissipation cost.

[0061] In one possible implementation, the specific implementation process of controlling the switch module corresponding to the battery cluster to disconnect the battery cluster from the DC bus in S102 includes:

[0062] When the energy storage system is detected to have triggered a charging or discharging restriction condition, the energy storage converter is prohibited from charging and discharging.

[0063] The control module corresponding to the first battery cluster disconnects the connection between the first battery cluster and the DC bus; the first battery cluster is any battery cluster with uneven charge.

[0064] After the first battery cluster is disconnected from the DC bus, the restrictions on charging and discharging of the energy storage converter are lifted.

[0065] Specifically, if there are battery clusters with uneven power levels, the main control unit will control the energy storage converter to prohibit charging and discharging when the energy storage system is fully charged (triggering the charging restriction condition) or fully discharged (triggering the discharging restriction condition). Then, it will send a switch module disconnection command and a converter module start command to the cluster-level control unit corresponding to the first battery cluster. The cluster-level control unit corresponding to the first battery cluster will disconnect the main contactor of the switch module corresponding to the first battery cluster and control the corresponding converter module to start. After completing the above operations, the cluster-level control unit will send switch module disconnection information and converter module start information to the main control unit. After receiving the switch module disconnection information and converter module start information, the main control unit will release the charging and discharging restriction of the energy storage converter so that other normal battery clusters are still connected to the DC bus and waiting for scheduling operation.

[0066] In one possible implementation, after the main contactor in the control switch module is disconnected, the main control unit obtains the SOC value of each battery cluster and determines the charging and discharging strategy after removing the first battery cluster based on the SOC value of each battery cluster.

[0067] In one possible implementation, after S102, the method provided in this embodiment further includes:

[0068] S201: Determine whether the first battery cluster has completed power balancing; the first battery cluster is any battery cluster with unbalanced power.

[0069] S202: If the first battery cluster has completed power balancing, determine whether the total voltage of the first battery cluster is the same as the bus voltage of the DC bus.

[0070] S203: If the total voltage of the first battery cluster is the same as the bus voltage of the DC bus, then control the switch module corresponding to the first battery cluster to close the connection between the first battery cluster and the DC bus, and control the converter module corresponding to the first battery cluster to turn off.

[0071] In one possible implementation, the specific implementation process of S201 includes:

[0072] Determine whether the first battery cluster triggers a preset prohibition condition; the preset prohibition condition includes a charging prohibition condition or a discharging prohibition condition.

[0073] If the first battery cluster triggers the preset prohibition condition, it is determined that the first battery cluster has completed power balancing, and the converter module corresponding to the first battery cluster is controlled to prohibit charging and discharging.

[0074] In this embodiment, the preset prohibition conditions include charging prohibition conditions and / or discharge prohibition conditions.

[0075] Specifically, if the battery clusters are balanced by charging, the three-phase power distribution terminal will rectify and boost the AC power through the converter module before sending it to the first battery cluster.

[0076] Correspondingly, when the cluster-level control unit corresponding to the first battery cluster detects that the total voltage of the first battery cluster has reached the full-charge voltage threshold, it triggers a charging-discharge restriction condition and controls the corresponding converter module to prohibit charging and discharging. The cluster-level control unit sends the charging-discharge restriction trigger command and the total voltage of the battery cluster to the main control unit. After detecting the charging-discharge restriction trigger command, the main control unit determines that the first battery cluster has completed power balancing and determines whether the total voltage of the first battery cluster is the same as the bus voltage of the DC bus. If the total voltage of the first battery cluster is the same as the bus voltage of the DC bus, it sends a switch module closing command and a converter module closing command to the cluster-level control unit corresponding to the first battery cluster. The cluster-level control unit controls the main contactor of the switch module to close and controls the corresponding converter module to close. Then, it sends the switch module closing information and the converter module closing information to the main control unit. The main control unit controls the energy storage converter to release the prohibition on charging and discharging based on the switch module closing information and the converter module closing information, so as to realize the access of the battery cluster.

[0077] The above method can reconnect the battery clusters to the DC bus when they are fully charged, and the control method is simple and precise.

[0078] In this embodiment, if the battery cluster is balanced by discharging, the first battery cluster will step down the DC voltage and invert it through the converter module before being delivered to the three-phase power distribution terminal of the energy storage system.

[0079] Correspondingly, when the cluster-level control unit corresponding to the first battery cluster detects that the total voltage of the first battery cluster has reached the discharge voltage threshold, it triggers the discharge restriction condition and controls the corresponding converter module to prohibit charging and discharging. The cluster-level control unit sends the discharge restriction condition trigger command and the total voltage of the battery cluster to the main control unit. After detecting the discharge restriction condition trigger command, the main control unit determines that the first battery cluster has completed power balancing and determines whether the total voltage of the first battery cluster is the same as the bus voltage of the DC bus. If the total voltage of the first battery cluster is the same as the bus voltage of the DC bus, it sends a switch module closing command and a converter module closing command to the cluster-level control unit corresponding to the first battery cluster. The cluster-level control unit controls the main contactor of the switch module to close and controls the corresponding converter module to close. Then, it sends the switch module closing information and the converter module closing information to the main control unit. The main control unit controls the energy storage converter to release the prohibition on charging and discharging according to the switch module closing information and the converter module closing information, so as to realize the access of the battery cluster.

[0080] The above method can reconnect the battery clusters to the DC bus when they have zero charge. The control method is simple and precise.

[0081] In one possible implementation, another step in S201 includes:

[0082] When the difference between the total voltage of the first battery cluster and the maximum total voltage of the battery cluster in the energy storage system is not greater than a preset voltage threshold, it is determined that the first battery cluster has completed power balancing.

[0083] Specifically, in this embodiment, the conditions for determining that the battery cluster has completed power balancing can include not only full charge and full discharge, but also, during the charging and discharging process, if the total voltage difference between the first battery cluster and the maximum total voltage difference between other battery clusters is not greater than a preset voltage difference, the battery cluster can be connected to the DC bus. This method requires precise calculation to determine the timing of the battery cluster connection, but it does not need to wait for the timing of other battery clusters to be fully charged / fully discharged, making the scheduling more flexible.

[0084] For example, the preset voltage difference can be 0.1V to 3V.

[0085] In one possible implementation, prior to S202, the method provided in this embodiment further includes:

[0086] Determine whether the energy storage converter is in a first state, where the first state is either a charging state or a discharging state.

[0087] If the energy storage converter is in the first state, then after detecting that the energy storage system has triggered a preset prohibition condition, the charging and discharging of the energy storage converter will be prohibited.

[0088] Accordingly, after S203, the method further includes:

[0089] Remove the restrictions on charging and discharging of the energy storage converter.

[0090] In this embodiment, after monitoring that the battery cluster to be balanced has completed the power balancing, it is determined whether other battery clusters are currently charging or discharging. If they are charging or discharging, the charging and discharging of the energy storage converter is prohibited after the energy storage converter stops charging or discharging, and then the battery cluster to be balanced is controlled to be connected to the DC bus. If other battery clusters are not charging or discharging, the energy storage converter has triggered the charging or discharging prohibition condition, and the battery cluster to be balanced can be directly controlled to be connected to the DC bus.

[0091] The above method can achieve high-power equalization management at the battery cluster level, thereby improving equalization management efficiency, avoiding the increase of differences between battery clusters, and equalizing only individual battery clusters. The energy storage system can still carry out normal charging and discharging, making it more flexible in application. It can perform equalization management at any time and is suitable for multiple application scenarios such as power generation-side power stations, grid-side power stations, and power consumption-side power stations.

[0092] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0093] The following are device embodiments of the present invention. For details not described in detail, please refer to the corresponding method embodiments described above.

[0094] Figure 4 A schematic diagram of the battery cluster-level equalization management device provided in an embodiment of the present invention is shown. For ease of explanation, only the parts related to the embodiment of the present invention are shown, and are described in detail below:

[0095] like Figure 4 As shown, the battery cluster-level equalization management device 100 includes:

[0096] The battery imbalance judgment module 110 is used to obtain the electrical parameters of each battery cluster and determine whether there are battery clusters with uneven power based on the electrical parameters of each battery cluster.

[0097] The online balancing module 120 is used to control the corresponding switch module of the battery cluster to disconnect the battery cluster from the DC bus and start the corresponding converter module of the battery cluster if there is a battery cluster with unbalanced power, so that the battery cluster can be balanced through the three-phase power distribution terminal.

[0098] In one possible implementation, the electrical parameters include battery voltage and SOC value; the battery imbalance judgment module 110 includes:

[0099] The difference between the current SOC value and the SOC reference value of each battery cluster is calculated to obtain the corresponding power deviation value of each battery cluster. Among them, when the battery clusters are charged for power balancing, the SOC reference value is the maximum SOC value of all battery clusters in the energy storage system; when the battery clusters are discharged for power balancing, the SOC reference value is the minimum SOC value of all battery clusters in the energy storage system.

[0100] If the power deviation of a battery cluster is greater than a preset deviation threshold, and the voltage difference between batteries within the battery cluster exceeds a preset voltage threshold, then the power of the battery cluster is determined to be unbalanced.

[0101] In one possible implementation, the online equalization module 120 includes a switching module control unit for:

[0102] When the energy storage system is detected to have triggered a charging or discharging restriction condition, the energy storage converter is prohibited from charging and discharging.

[0103] The control module corresponding to the first battery cluster disconnects the connection between the first battery cluster and the DC bus; the first battery cluster is any battery cluster with uneven charge.

[0104] After the first battery cluster is disconnected from the DC bus, the restrictions on charging and discharging of the energy storage converter are lifted.

[0105] In one possible implementation, the battery cluster-level equalization management device 100 further includes a recovery module, specifically comprising:

[0106] The equalization completion judgment unit is used to determine whether the first battery cluster has completed the power equalization; the first battery cluster is any battery cluster with unbalanced power.

[0107] The voltage determination unit is used to determine whether the total voltage of the first battery cluster is the same as the bus voltage of the DC bus if the first battery cluster has completed power balancing.

[0108] The switch module closing unit is used to control the switch module corresponding to the first battery cluster to close the connection between the first battery cluster and the DC bus if the total voltage of the first battery cluster is the same as the bus voltage of the DC bus, and to control the converter module corresponding to the first battery cluster to turn off.

[0109] In one possible implementation, the equalization completion judgment unit includes:

[0110] Determine whether the first battery cluster triggers a preset prohibition condition; the preset prohibition condition includes a charging prohibition condition or a discharging prohibition condition.

[0111] If the first battery cluster triggers the preset prohibition condition, it is determined that the first battery cluster has completed power balancing, and the converter module corresponding to the first battery cluster is controlled to prohibit charging and discharging.

[0112] In one possible implementation, the equalization completion judgment unit includes:

[0113] When the difference between the total voltage of the first battery cluster and the maximum total voltage of the battery cluster in the energy storage system is not greater than a preset voltage threshold, it is determined that the first battery cluster has completed power balancing.

[0114] In one possible implementation, the recovery module further includes a converter control unit for:

[0115] Determine whether the energy storage converter is in a first state, where the first state is either a charging state or a discharging state.

[0116] If the energy storage converter is in the first state, then after detecting that the energy storage system has triggered a preset prohibition condition, the charging and discharging of the energy storage converter will be prohibited.

[0117] Accordingly, the recovery module also includes a charging / discharging disabling unit, used for:

[0118] Remove the restrictions on charging and discharging of the energy storage converter.

[0119] Figure 5 This is a schematic diagram of the controller provided in an embodiment of the present invention. Figure 5 As shown, the controller 5 in this embodiment includes a processor 50 and a memory 51. The memory 51 stores a computer program 52, and the processor 50 calls and runs the computer program 52 stored in the memory 51 to execute the steps described in the various battery cluster-level equalization management method embodiments above, for example... Figure 3 The steps S101 to S102 are shown. Alternatively, the processor 50 is used to call and run the computer program 52 stored in the memory 51 to implement the functions of each module / unit in the above-described device embodiments, for example... Figure 4 The functions of modules 110 to 120 are shown.

[0120] For example, the computer program 52 can be divided into one or more modules / units, which are stored in the memory 51 and executed by the processor 50 to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program 52 in the controller 5. For example, the computer program 52 can be divided into... Figure 4 Modules 110 to 120 are shown.

[0121] The controller 5 can be a computing device such as a desktop computer, laptop, handheld computer, or cloud server. The controller 5 may include, but is not limited to, a processor 50 and a memory 51. Those skilled in the art will understand that... Figure 5 This is merely an example of controller 5 and does not constitute a limitation on controller 5. It may include more or fewer components than shown, or combine certain components, or different components. For example, the controller may also include input / output devices, network access devices, buses, etc.

[0122] The processor 50 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0123] The memory 51 can be an internal storage unit of the controller 5, such as a hard disk or memory of the controller 5. The memory 51 can also be an external storage device of the controller 5, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card equipped on the controller 5. Furthermore, the memory 51 can include both internal storage units and external storage devices of the controller 5. The memory 51 is used to store the computer program and other programs and data required by the controller. The memory 51 can also be used to temporarily store data that has been output or will be output.

[0124] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0125] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0126] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0127] In the embodiments provided by this invention, it should be understood that the disclosed devices / controllers and methods can be implemented in other ways. For example, the device / controller embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0128] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0129] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0130] If the integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various battery cluster-level equalization management method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc. It should be noted that the content contained in the computer-readable medium may be appropriately added to or subtracted from the content as required by the legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium may not include electrical carrier signals and telecommunication signals.

[0131] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A battery cluster level equalization management method, characterized by, The application is applied to an energy storage system, the energy storage system comprises an energy storage converter, a plurality of battery clusters and a high-voltage box corresponding to each battery cluster; the high-voltage box comprises a switching module and a conversion module; each battery cluster is connected with the first end of the corresponding switching module and the first end of the conversion module, the second end of each switching module is connected with the energy storage converter through a DC bus, and the second end of each conversion module is connected with a three-phase power distribution end of the energy storage system; The method comprises: obtaining the electrical parameters of each battery cluster, and determining whether there is a battery cluster with unbalanced power according to the electrical parameters of each battery cluster; if there is a battery cluster with unbalanced power, controlling the switching module corresponding to the battery cluster to disconnect the connection between the battery cluster and the DC bus, and starting the conversion module corresponding to the battery cluster to make the battery cluster balance power through the three-phase power distribution end; the electrical parameters include battery voltage and SOC value; determining whether there is a battery cluster with unbalanced power according to the electrical parameters of each battery cluster comprises: calculating the difference between the current SOC value of each battery cluster and the SOC reference value to obtain the power deviation value corresponding to each battery cluster; when the battery cluster balances power in the charging mode, the SOC reference value is the maximum SOC value of all battery clusters in the energy storage system; when the battery cluster balances power in the discharging mode, the SOC reference value is the minimum SOC value of all battery clusters in the energy storage system; if the power deviation value of a battery cluster is greater than a preset deviation threshold value, and the battery voltage difference between the batteries in the battery cluster exceeds a preset voltage threshold value, it is determined that the power of the battery cluster is unbalanced.

2. The battery cluster level equalization management method of claim 1, wherein, The DC end of the energy storage converter is connected with the DC bus, and the AC end of the energy storage converter is connected with the power grid; controlling the switching module corresponding to the battery cluster to disconnect the connection between the battery cluster and the DC bus comprises: when it is monitored that the energy storage system triggers the forbidden charging condition or the forbidden discharging condition, the energy storage converter is prohibited from charging and discharging; controlling the switching module corresponding to the first battery cluster to disconnect the connection between the first battery cluster and the DC bus; the first battery cluster is any battery cluster with unbalanced power; after the first battery cluster is disconnected from the DC bus, the prohibition of charging and discharging of the energy storage converter is removed.

3. The battery cluster level equalization management method of claim 1, wherein, after starting the conversion module corresponding to the battery cluster, the method further comprises: determining whether the first battery cluster has completed power balancing; the first battery cluster is any battery cluster with unbalanced power; if the first battery cluster has completed power balancing, determining whether the total voltage of the battery cluster of the first battery cluster is the same as the bus voltage of the DC bus; if the total voltage of the battery cluster of the first battery cluster is the same as the bus voltage of the DC bus, controlling the switching module corresponding to the first battery cluster to close the connection between the first battery cluster and the DC bus, and controlling the conversion module corresponding to the first battery cluster to close.

4. The battery cluster level equalization management method of claim 3, wherein, determining whether the first battery cluster has completed power balancing comprises: determining whether the first battery cluster triggers a preset prohibition condition; the preset prohibition condition comprises a forbidden charging condition or a forbidden discharging condition; If the first battery cluster triggers the preset prohibition condition, it is determined that the first battery cluster has completed the power balance, and the current module corresponding to the first battery cluster is controlled to prohibit charging and discharging.

5. The battery cluster level equalization management method of claim 3, wherein, The method further includes: If the difference between the total voltage of the first battery cluster and the maximum total voltage of the battery clusters in the energy storage system is not greater than a preset voltage threshold, it is determined that the first battery cluster has completed the power balance.

6. The battery cluster level equalization management method according to claim 4 or 5, characterized by, The DC end of the energy storage converter is connected with the DC bus, and the AC end of the energy storage converter is connected with the power grid. Before the determination of whether the total voltage of the first battery cluster is the same as the bus voltage of the DC bus, the method further includes: It is determined whether the energy storage converter is in a first state, and the first state is a charging state or a discharging state. If the energy storage converter is in the first state, after it is monitored that the energy storage system triggers the preset prohibition condition, the energy storage converter is prohibited from charging and discharging. Correspondingly, after the control of the current module corresponding to the first battery cluster is closed, the method further includes: The prohibition of charging and discharging of the energy storage converter is released.

7. A controller characterized by comprising: The controller includes a processor and a memory, the memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to execute the battery cluster level balance management method.

8. A computer-readable storage medium storing a computer program, the computer-readable storage medium comprising: The computer program is executed by the processor to implement the battery cluster level balance management method.

9. An energy storage system characterized by, The controller includes the controller according to claim 7. The computer program is executed by the processor to implement the battery cluster level balance management method.

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