Energy storage battery equalization management method, controller, storage medium and energy storage system

Abstract

The application provides a kind of energy storage battery equalization management method, controller, storage medium and energy storage system.The energy storage system to which the method is applied is connected in parallel with a DCDC module at the switch module in the high-pressure box of each battery cluster, and can determine whether there is an unbalanced battery cluster according to the electrical parameters of each battery cluster;if there is an unbalanced battery cluster, then the switch module corresponding to each battery cluster is controlled to disconnect the connection between the corresponding battery cluster and the DC bus;the DCDC module corresponding to each battery cluster is started, and the DCDC module corresponding to each battery cluster is controlled to balance the power of the corresponding battery cluster with the equalization power of each battery cluster respectively.The above-mentioned method can balance all battery clusters through DCDC module when the power of battery clusters is unbalanced, so as to realize the rapid equalization between battery clusters.

Description

Technical Field

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

[0002] A battery cluster consists of multiple batteries connected in series or in parallel. Series connection increases the battery terminal voltage, while parallel connection increases battery capacity. Each battery cluster is connected to an energy storage converter, 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 cause the entire system to shut down, resulting in a decrease in the usable capacity of the entire battery pack. Although existing cell control units are designed with passive balancing to address these inconsistencies, the power of this balancing method is too low. After long-term operation, the passive balancing capability cannot compensate for the cell's own degradation, leading to a gradual widening of inconsistencies between individual cells. Summary of the Invention

[0004] This invention provides a method, controller, storage medium, and energy storage system for equalizing energy storage batteries, in order to solve the problem of ever-increasing differences between battery clusters in the prior art.

[0005] In a first aspect, embodiments of the present invention provide an energy storage battery equalization management method, applied to an energy storage system, the energy storage system including multiple battery clusters and a high-voltage box corresponding to each battery cluster; the high-voltage box includes a switching module and a DC-DC module;

[0006] The first terminal of each switching module and the first terminal of each DCDC module are connected to the DC bus of the energy storage system, and the second terminal of each switching module and the second terminal of each DCDC module are connected to the corresponding battery cluster.

[0007] The method includes:

[0008] 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;

[0009] If there are battery clusters with uneven power levels, the corresponding switch module of each battery cluster will be controlled to disconnect the connection between the corresponding battery cluster and the DC bus.

[0010] Start the DC-DC module corresponding to each battery cluster and control the DC-DC module corresponding to each battery cluster to operate at its own equalization power, so that the power grid can balance the power of each battery cluster; the equalization power of each DC-DC module is related to the electrical parameters of the corresponding battery cluster.

[0011] 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 energy storage battery equalization management method as described in any possible implementation of the first aspect above.

[0012] 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 energy storage battery equalization management method as described in any possible implementation of the first aspect above.

[0013] Fourthly, embodiments of the present invention provide an energy storage system, which includes the controller described in the third aspect above.

[0014] This invention provides a battery equalization management method, controller, storage medium, and energy storage system. The method is applied to an energy storage system, where a DC-DC converter module is connected in parallel to the switching module in the high-voltage box of each battery cluster. This module can determine whether there are battery clusters with uneven charge levels based on their electrical parameters. If uneven battery clusters exist, the corresponding switching module for each battery cluster disconnects the connection between the corresponding battery cluster and the DC bus. The DC-DC converter module for each battery cluster is then activated and used to perform charge equalization for its respective battery cluster at its own equalization power. This method enables higher-power equalization management of battery clusters when there is an imbalance, thereby accelerating the equalization management speed and preventing the differences between battery clusters from increasing. Furthermore, the DC-DC converter module provided in this application only needs to equalize the difference in charge level 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

[0015] 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.

[0016] Figure 1This is an application scenario diagram of the structural schematic diagram of the energy storage system provided in the embodiments of the present invention;

[0017] Figure 2 This is a circuit diagram of the DC-DC module provided in an embodiment of the present invention;

[0018] Figure 3 This is a flowchart illustrating the implementation of the energy storage battery equalization management method provided in this embodiment of the invention.

[0019] Figure 4 This is a schematic diagram of the structure of the energy storage battery equalization management device provided in an embodiment of the present invention;

[0020] Figure 5 This is a schematic diagram of the controller provided in an embodiment of the present invention. Detailed Implementation

[0021] 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.

[0022] 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.

[0023] Figure 1 This is a schematic diagram of the energy storage system provided in an embodiment of the present invention. 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 switching module and a DC-DC module.

[0024] The first terminal of each switching module and the first terminal of each DC-DC module are connected to the DC bus of the energy storage system, and the second terminal of each switching module and the second terminal of each DC-DC module are connected to the corresponding battery cluster.

[0025] 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 DC-DC module is turned on, thereby balancing the power of the battery cluster through the DC-DC module.

[0026] In one possible implementation, the DC-DC module includes:

[0027] First capacitor, second capacitor, third capacitor, first inductor, first switching unit, second switching unit, third switching unit and fourth switching unit;

[0028] The first end of the first inductor is connected to the positive terminal of the first terminal of the DC-DC module. The second end of the first inductor is connected to the first terminal of the first switching unit, the first terminal of the third switching unit, and the first terminal of the first capacitor. The second terminal of the first switching unit is connected to the first terminal of the second switching unit. The second terminal of the second switching unit and the second terminal of the first capacitor are connected to the negative terminal of the DC-DC module. The second terminal of the third switching unit is connected to the first terminal of the fourth switching unit. The second terminal of the fourth switching unit is connected to the positive terminal of the second terminal of the DC-DC module. The first terminal of the second capacitor is connected to the first terminal of the second switching unit. The second terminal of the second capacitor is connected to the second terminal of the third switching unit. The third capacitor is connected between the positive and negative terminals of the output terminal of the DC-DC module.

[0029] Specifically, Figure 2 The proposed circuit structure of the DC-DC module enables the power grid to balance the power of each battery cluster by charging, thereby improving the battery cluster balancing efficiency.

[0030] In one possible implementation, such as Figure 1 As shown, with Figure 1 Taking the first battery cluster as an example, the switching module includes a main contactor KM1-1; the first end of the main contactor KM1-1 is connected to the DC bus, and the second end of the main contactor KM1-1 is connected to the corresponding battery cluster.

[0031] In one possible implementation, the switching module further includes a secondary contactor KM1-2 and a first resistor R1;

[0032] The first end of the first resistor R1 is connected to the DC bus, the second end of the first resistor R1 is connected to the first end of the auxiliary contactor KM1-2, and the second end of the auxiliary contactor KM1-2 is connected to the corresponding battery cluster.

[0033] In one possible implementation, the DC-DC module is a bidirectional DC-DC circuit. By setting a bidirectional DC-DC circuit, the charge balance of unbalanced battery clusters can be achieved by charging or discharging.

[0034] In one possible implementation, such as Figure 1 As shown, the high-voltage box also includes a disconnecting switch QS1;

[0035] The first end of the disconnecting switch QS1 is connected to the DC bus, and the second end of the disconnecting switch QS1 is connected to the first end of the switch module and the first end of the DC-DC module, respectively.

[0036] In one possible implementation, a fuse is connected between the battery cluster and the second end of the main contactor.

[0037] In one possible implementation, the cluster-level optimizer further includes a first filtering module;

[0038] The first end of the first filter module is connected to the DC bus, and the second end of the first filter module is connected to the first end of the DCDC module.

[0039] In one possible implementation, the cluster-level optimizer further includes a second filtering module;

[0040] The first end of the second filter module is connected to the second end of the DCDC module; the second end of the second filter module is connected to the corresponding battery cluster.

[0041] 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;

[0042] 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, DC-DC module, and battery control unit of each battery in the corresponding battery cluster. The battery control unit is communicatively connected to the corresponding battery.

[0043] In one possible implementation, the main control unit and each cluster-level control unit are connected via a CAN bus. The main control unit is connected to the energy storage converter via the CAN bus and dry contacts. Each cluster-level control unit is connected to its corresponding DC-DC module via dry contacts.

[0044] In one possible implementation, the cluster-level control unit and each battery control unit are connected via a CAN bus. Each battery control unit is connected to its corresponding battery via a dry contact.

[0045] In one possible implementation, the main control unit is also connected to the dehumidifier, liquid chiller and air conditioner of the energy storage system via RS485 bus, and is connected to devices such as operation lights, fault lights, fire alarm, fire action, UPS, emergency stop feedback, water immersion feedback and door status via dry contacts.

[0046] The aforementioned cluster-level optimizer and its energy storage system can perform offline, high-power energy balancing of all battery clusters when imbalances occur between them, thereby accelerating the cluster-level balancing efficiency of the energy storage system and preventing the increase of differences between battery clusters.

[0047] See Figure 2 The diagram illustrates the implementation flowchart of the energy storage battery balancing management method provided in this embodiment of the invention, which is described in detail below:

[0048] 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.

[0049] 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.

[0050] 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 determines 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.

[0051] In one possible implementation, the electrical parameters include battery voltage and SOC value; the specific implementation process of S101 includes:

[0052] 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.

[0053] 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.

[0054] 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.

[0055] Specifically, using the method described above for determining unbalanced battery clusters based on the maximum SOC value, after identifying the unbalanced clusters, a charging method is needed to balance all battery clusters to achieve equal power levels. During the charging process, when performing power balance detection, the SOC value of each battery cluster is the maximum SOC value among the SOC values ​​of all cells within that cluster. Similarly, using the method described above for determining unbalanced battery clusters based on the minimum SOC value, after identifying the unbalanced clusters, a discharging method is needed to balance all battery clusters to achieve equal power levels. During the discharging process, when performing power balance detection, the SOC value of each battery cluster is the minimum SOC value among the SOC values ​​of all cells within that cluster.

[0056] 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.

[0057] S102: If there are battery clusters with uneven power levels, control the corresponding switch module of each battery cluster to disconnect the connection between the corresponding battery cluster and the DC bus.

[0058] In this embodiment, when an unevenly charged battery cluster is detected, a switch module disconnect command and a DC-DC module start command are sent to each cluster-level control unit. After receiving the switch module disconnect command and the DC-DC module start command, the cluster-level control unit first disconnects the main contactor in the corresponding switch module, and then controls the DC-DC module corresponding to the battery cluster to start. The DC-DC module enables high-power charging and discharging of the battery cluster, thereby achieving rapid equalization of the battery cluster.

[0059] In one possible implementation, the specific implementation process of S102 includes:

[0060] If there are battery clusters with uneven charge levels, the energy storage converter will be prohibited from charging and discharging when the energy storage system is detected to have triggered a preset prohibition condition; the preset prohibition condition includes a charging prohibition condition and / or a discharging prohibition condition.

[0061] Upon receiving the user's cluster-level equalization confirmation command, the energy storage converter and all main contactors are shut down.

[0062] Accordingly, after activating the DC-DC modules corresponding to each battery cluster, the method provided in this embodiment further includes:

[0063] Control the start-up of the energy storage converter and release the restrictions on charging and discharging of the energy storage converter.

[0064] Specifically, if there are battery clusters with uneven charge levels, the main control unit will control the energy storage inverter 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, the main control unit will obtain the remaining available capacity of the energy storage system and generate a battery cluster balancing prompt message. After seeing the battery cluster balancing prompt message, if the user confirms the battery cluster balancing, the main control unit will generate a cluster-level balancing confirmation command and control the energy storage inverter to shut down according to the cluster-level balancing confirmation command. It will also send a switch module shutdown command to the cluster-level control unit corresponding to each battery cluster. The cluster-level control unit will control the main contactor of the corresponding switch module to disconnect based on the switch module shutdown command, so that all battery clusters are disconnected from the energy storage inverter PCS.

[0065] S103: Start the DC-DC module corresponding to each battery cluster, and control the DC-DC module corresponding to each battery cluster to operate at its own equalization power, so that the power grid can balance the power of each battery cluster; the equalization power of each DC-DC module is related to the electrical parameters of the corresponding battery cluster.

[0066] The above method can perform high-power equalization management of battery clusters using a DC-DC module 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 DC-DC module 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.

[0067] In one possible implementation, after the restrictions on charging and discharging of the energy storage converter are lifted, the method provided in this embodiment further includes:

[0068] When performing power balancing on the battery cluster in a charging manner, the energy storage converter is controlled to operate at a first voltage; the first voltage is greater than the total voltage of the target battery cluster.

[0069] When performing charge balancing on the battery cluster by discharging, the energy storage converter is controlled to operate at a second voltage, which is less than the total voltage of the target battery cluster.

[0070] In this embodiment, when the main control unit sends a switch module shutdown command to each cluster-level control unit, it simultaneously issues a DC-DC module start command. After the main contactor of the switch module corresponding to each battery cluster is disconnected, the cluster-level control unit controls the corresponding DC-DC module to start based on the DC-DC module start command and stops the pulse, so that the DC-DC module operates in constant voltage mode. Then, the cluster-level control unit sends DC-DC start information to the main control unit. After receiving the DC-DC start information, if the main control unit performs charge balancing on the battery cluster in charging mode, it adjusts the equalization charging voltage of the energy storage converter to the first voltage; if it performs charge balancing on the battery cluster in discharging mode, it controls the discharge voltage of the energy storage converter to adjust to the second voltage to ensure that there is a voltage difference between the energy storage converter and the battery cluster during the voltage boost (charging) or voltage buck (discharging) process.

[0071] For example, the difference between the first voltage and the total voltage of the target battery cluster can be 40V to 60V, and the difference between the second voltage and the total voltage of the target battery cluster can also be 40V to 60V. Preferably, the difference can be 50V.

[0072] Specifically, during charging, the target total voltage of the battery cluster can be the highest among all battery clusters; during discharging, the target total voltage of the battery cluster can be the lowest among all battery clusters.

[0073] In this embodiment, after determining the operating voltage of the energy storage converter, the energy storage converter is started and the charging and discharging restrictions on the energy storage converter are lifted. After lifting the charging and discharging restrictions on the energy storage converter, when performing charge balancing on the battery cluster in charging mode, the energy storage converter is controlled to operate at a first voltage; when performing charge balancing on the battery cluster in discharging mode, the energy storage converter is controlled to operate at a second voltage.

[0074] In one possible implementation, the electrical parameter includes the SOC value; the specific implementation process of S103 includes:

[0075] Control the parallel operation of the DCDC modules corresponding to each battery cluster;

[0076] During operation, the equalization power of the corresponding DC-DC module is determined based on the SOC equalization value of each battery cluster. The SOC equalization value is positively correlated with the equalization power. The SOC equalization value is the difference between the current SOC value and the target SOC value of the battery cluster.

[0077] Control the DC-DC modules corresponding to each battery cluster to operate at the corresponding balanced power.

[0078] Specifically, after the main control unit starts the energy storage converter, it simultaneously sends DC-DC parallel operation commands to each cluster-level control unit. Each cluster-level control unit controls the corresponding DC-DC module to operate in parallel and boost at the DC bus terminal according to the DC-DC parallel operation command. During operation, the equalization power of the corresponding DC-DC module is determined according to the SOC to be equalized value of each battery cluster, so as to ensure that the charging and discharging progress of each battery cluster is consistent as much as possible, reduce the difference in equalization completion time between each battery cluster, and accelerate the progress of the equalization task.

[0079] In one possible implementation, the electrical parameter includes the SOC value; after S103, the method provided in this embodiment further includes:

[0080] S201: Determine whether each battery cluster has completed power balancing, and control the DC-DC module corresponding to the battery cluster that has completed power balancing to prohibit charging and discharging.

[0081] S202: Determine whether all battery clusters have completed power balancing. If all battery clusters have completed power balancing, then turn off the DC-DC module corresponding to each battery cluster.

[0082] S203: Determine whether the difference between the maximum and minimum total voltage of all battery clusters is less than a preset voltage threshold. If the difference between the maximum and minimum total voltage of all battery clusters is less than the preset voltage threshold, then control each switch module to close the connection between the corresponding battery cluster and the DC bus.

[0083] In this embodiment, the method for determining power balance includes:

[0084] Determine whether the first battery cluster has triggered a preset prohibition condition. If the preset prohibition condition is triggered, it is determined that the first battery cluster has completed power balancing. The preset prohibition conditions include charging prohibition conditions and / or discharging prohibition conditions. The first battery cluster is any battery cluster in the energy storage system.

[0085] In this embodiment, if the battery cluster is balanced by charging, the grid signal is transmitted to the first battery cluster after passing through the PCS and DC-DC modules.

[0086] Specifically, when the cluster-level control unit corresponding to the first battery cluster detects that the total voltage of the first battery cluster reaches the full charge voltage threshold or the SOC value of the first battery cluster reaches the full charge SOC threshold, it triggers a charging prohibition condition and controls the DC-DC module corresponding to the first battery cluster to prohibit charging and discharging. The cluster-level control unit sends the charging prohibition condition trigger command and the total voltage of the battery cluster to the main control unit. After detecting the charging prohibition condition trigger command, the main control unit determines that the first battery cluster has completed power balancing.

[0087] In this embodiment, if the battery cluster is balanced by discharging, the first battery cluster is discharged to the power grid after passing through the DC-DC module and PCS.

[0088] Specifically, when the cluster-level control unit corresponding to the first battery cluster detects that the total voltage of the first battery cluster reaches the full discharge voltage threshold or the SOC value of the first battery cluster reaches the full discharge SOC threshold, it triggers the discharge restriction condition and controls the DC-DC module corresponding to the first battery cluster to prohibit charging and discharging. The cluster-level control unit sends the charge restriction condition trigger command and the total voltage of the battery cluster to the main control unit. After detecting the charge restriction condition trigger command, the main control unit determines that the first battery cluster has completed power balancing.

[0089] In this embodiment, when it is determined that the first battery cluster has completed power balancing, a DC-DC charging and discharging prohibition command is issued to the cluster-level control unit corresponding to the first battery cluster. The cluster-level control unit prohibits the corresponding DC-DC charging and discharging according to the DC-DC charging and discharging prohibition command and stops the pulse.

[0090] In one possible implementation, the specific implementation process of S202 includes:

[0091] If all battery clusters trigger the preset prohibition condition, or if the difference between the maximum value and the minimum value of the total voltage of all battery clusters is less than the preset voltage threshold, then it is determined that all battery clusters have completed power balancing.

[0092] The preset prohibition conditions include conditions prohibiting charging and / or conditions prohibiting discharging.

[0093] Specifically, in this embodiment, the conditions for determining that the battery clusters have completed power balancing can include not only full charge and full discharge, but also, during the charging and discharging process, if the difference between the total voltage of the largest battery cluster and the total voltage of the smallest battery cluster is not greater than a preset voltage difference, it indicates that the total voltage of all battery clusters is close, and it can be determined that all battery clusters have completed power balancing. This method requires precise calculation to determine the timing of power balancing, but it does not need to wait for all battery clusters to be fully charged / fully discharged before exiting the balancing mode, making the scheduling more flexible.

[0094] For example, the preset voltage difference can be 0.1V to 3V.

[0095] Specifically, after the main control unit detects that all battery clusters have completed power balancing, it controls the energy storage converter PCS and all DC-DC modules to shut down in tandem. Specifically, the main control unit first shuts down the energy storage converter, and then sends a DC-DC shutdown command to the cluster-level control units corresponding to all battery clusters. Each cluster-level control unit controls its corresponding DC-DC module to shut down according to the DC-DC shutdown command. Then, the cluster-level control unit sends the shutdown information of the corresponding DC-DC module to the main control unit. After detecting the shutdown information of the DC-DC modules corresponding to all battery clusters, the main control unit determines whether the difference between the maximum and minimum total voltage of all battery clusters is less than a preset voltage threshold. If the difference is less than the preset voltage threshold, it sends a switch module closing command to the cluster-level control units of all battery clusters. The cluster-level control units then close the main contactor of the corresponding switch module according to the switch module closing command. After the main contactor closes, each cluster-level control unit is also used to send the closing information of the switch modules to the main control unit. After receiving the closing information of all switch modules, the main control unit adjusts the operating voltage of the energy storage converter to the voltage under normal charging and discharging conditions. The main control unit updates the current available capacity of the energy storage system, and the energy storage system resumes normal operation.

[0096] The above method enables simultaneous high-power equalization management of all cells in each battery cluster, thereby improving equalization management efficiency, extending the life of the entire battery compartment, and avoiding increased differences between battery clusters. In scenarios where there is no scheduling requirement for the energy storage system and grid charging and discharging is permitted, it can quickly achieve equalization management at the battery cluster level. Furthermore, the software operation logic between the battery cluster-level optimizer, energy storage converter, and battery cluster provided by this solution is simple and does not require much adjustment within the existing software program framework. It is easy to implement and applicable to multiple application scenarios such as power generation-side power plants, grid-side power plants, and power consumption-side power plants.

[0097] 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.

[0098] The following are device embodiments of the present invention. For details not described in detail, please refer to the corresponding method embodiments described above.

[0099] Figure 4 A schematic diagram of the structure of the energy storage battery 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:

[0100] like Figure 4 As shown, the energy storage battery equalization management device 100 includes:

[0101] The equalization judgment module 110 is used to obtain the electrical parameters of each battery cluster and determine whether there are battery clusters with unbalanced power based on the electrical parameters of each battery cluster.

[0102] The switch module control module 120 is used to control the switch module corresponding to each battery cluster to disconnect the connection between the corresponding battery cluster and the DC bus if there are battery clusters with uneven power.

[0103] The DCDC control module 130 is used to start the DCDC module corresponding to each battery cluster and control the DCDC module corresponding to each battery cluster to operate at their respective equalization power, so that the power grid can balance the power of each battery cluster; the equalization power of each DCDC module is related to the electrical parameters of the corresponding battery cluster.

[0104] In one possible implementation, the electrical parameters include battery voltage and SOC value; the equalization judgment module 110 includes:

[0105] 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.

[0106] 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.

[0107] In one possible implementation, the energy storage system further includes an energy storage converter; the DC terminal of the energy storage converter is connected to the DC bus, and the AC terminal of the energy storage converter is connected to the power grid; the switching module includes a main contactor, one end of which is connected to the DC bus, and the other end is connected to the corresponding battery cluster.

[0108] The switch module control module 120 includes:

[0109] If there are battery clusters with uneven charge levels, the energy storage converter will be prohibited from charging and discharging when the energy storage system is detected to have triggered a preset prohibition condition; the preset prohibition condition includes a charging prohibition condition and / or a discharging prohibition condition.

[0110] Upon receiving the user's cluster-level equalization confirmation command, the energy storage converter and all main contactors are shut down.

[0111] Accordingly, the device 100 provided in this embodiment also includes an energy storage converter deactivation module, used for:

[0112] Control the start-up of the energy storage converter and release the restrictions on charging and discharging of the energy storage converter.

[0113] In one possible implementation, the device provided in this embodiment further includes an energy storage converter control module, comprising:

[0114] When performing power balancing on the battery cluster in a charging manner, the energy storage converter is controlled to operate at a first voltage; the first voltage is greater than the total voltage of the target battery cluster.

[0115] When performing charge balancing on the battery cluster by discharging, the energy storage converter is controlled to operate at a second voltage, which is less than the total voltage of the target battery cluster.

[0116] In one possible implementation, the electrical parameters include the SOC value; the DC-DC control module 130 includes:

[0117] Control the parallel operation of the DCDC modules corresponding to each battery cluster;

[0118] During operation, the equalization power of the corresponding DC-DC module is determined based on the SOC equalization value of each battery cluster. The SOC equalization value is positively correlated with the equalization power. The SOC equalization value is the difference between the current SOC value and the target SOC value of the battery cluster.

[0119] Control the DC-DC modules corresponding to each battery cluster to operate at the corresponding balanced power.

[0120] In one possible implementation, the electrical parameters include the SOC value; the device 100 provided in this embodiment further includes a recovery module, which specifically includes:

[0121] The single-cluster equalization completion judgment unit is used to determine whether each battery cluster has completed power equalization and to control the DCDC module corresponding to the battery cluster that has completed power equalization to prohibit charging and discharging.

[0122] The overall balancing completion judgment unit is used to determine whether all battery clusters have completed power balancing. If all battery clusters have completed power balancing, the DC-DC module corresponding to each battery cluster is turned off.

[0123] The recovery unit is used to determine whether the difference between the maximum and minimum total voltage of all battery clusters is less than a preset voltage threshold. If the difference between the maximum and minimum total voltage of all battery clusters is less than the preset voltage threshold, then each switch module is controlled to close the connection between the corresponding battery cluster and the DC bus.

[0124] In one possible implementation, the overall balance completion judgment unit includes:

[0125] If all battery clusters trigger the preset prohibition condition, or if the difference between the maximum value and the minimum value of the total voltage of all battery clusters is less than the preset voltage threshold, then it is determined that all battery clusters have completed power balancing.

[0126] The preset prohibition conditions include conditions prohibiting charging and / or conditions prohibiting discharging.

[0127] 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 embodiments of the energy storage battery equalization management method, for example... Figure 3 The steps S101 to S103 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 130 are shown.

[0128] 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 130 are shown.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] 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.

[0136] 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.

[0137] 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.

[0138] 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 energy storage battery 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.

[0139] 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 method for equalizing energy storage batteries, characterized in that, This is applied to an energy storage system, which includes multiple battery clusters and a high-voltage box corresponding to each battery cluster; the high-voltage box includes a switching module and a DC-DC module. The first terminal of each switching module and the first terminal of each DCDC module are connected to the DC bus of the energy storage system, and the second terminal of each switching module and the second terminal of each DCDC module are connected to the corresponding battery cluster. The method includes: 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; If there are battery clusters with uneven power levels, the corresponding switch module of each battery cluster will be controlled to disconnect the connection between the corresponding battery cluster and the DC bus. Start the DC-DC module corresponding to each battery cluster and control the DC-DC module corresponding to each battery cluster to operate at their respective equalization power, so that the power grid can balance the power of each battery cluster; the equalization power of each DC-DC module is related to the electrical parameters of the corresponding battery cluster. The electrical parameters include battery voltage and SOC value; The step of determining whether there are battery clusters with uneven power levels based on the electrical parameters of each battery cluster includes: 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. 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. The control of the DC-DC modules corresponding to each battery cluster to operate at their respective equalization power, so that the power grid performs power equalization for each battery cluster, includes: Control the parallel operation of the DCDC modules corresponding to each battery cluster; During operation, the equalization power of the corresponding DC-DC module is determined based on the SOC equalization value of each battery cluster. The SOC equalization value is positively correlated with the equalization power. The SOC equalization value is the difference between the current SOC value and the target SOC value of the battery cluster. Control the DC-DC modules corresponding to each battery cluster to operate at the corresponding balanced power.

2. The energy storage battery equalization management method according to claim 1, characterized in that, The energy storage system also includes an energy storage converter; the DC terminal of the energy storage converter is connected to the DC bus, and the AC terminal of the energy storage converter is connected to the power grid; the switch module includes a main contactor, one end of which is connected to the DC bus, and the other end is connected to the corresponding battery cluster. If there are battery clusters with uneven power levels, the corresponding switch module for each battery cluster will be controlled to disconnect the connection between the corresponding battery cluster and the DC bus, including: If there are battery clusters with uneven charge levels, the energy storage converter will be prohibited from charging and discharging when the energy storage system is detected to have triggered a preset prohibition condition; the preset prohibition condition includes a charging prohibition condition and / or a discharging prohibition condition. Upon receiving the user's cluster-level equalization confirmation command, the energy storage converter and all main contactors are shut down. Accordingly, after activating the DC-DC module corresponding to each battery cluster, the method further includes: Control the start-up of the energy storage converter and release the restrictions on charging and discharging of the energy storage converter.

3. The energy storage battery equalization management method according to claim 2, characterized in that, After the restrictions on charging and discharging of the energy storage converter are lifted, the method further includes: When performing power balancing on the battery cluster in a charging manner, the energy storage converter is controlled to operate at a first voltage; the first voltage is greater than the total voltage of the target battery cluster. When performing charge balancing on the battery cluster by discharging, the energy storage converter is controlled to operate at a second voltage, which is less than the total voltage of the target battery cluster.

4. The energy storage battery equalization management method according to claim 1, characterized in that, After controlling the DC-DC modules corresponding to each battery cluster to operate at their respective equalization power, so that the power grid performs power equalization for each battery cluster, the method further includes: Determine whether each battery cluster has achieved power balancing, and control the DC-DC module corresponding to the battery cluster that has achieved power balancing to prevent charging and discharging; Determine whether all battery clusters have completed power balancing. If all battery clusters have completed power balancing, then turn off the DC-DC module corresponding to each battery cluster. Determine whether the difference between the maximum and minimum total voltage of all battery clusters is less than a preset voltage threshold. If the difference is less than the preset voltage threshold, control each switch module to close the connection between the corresponding battery cluster and the DC bus.

5. The energy storage battery equalization management method according to claim 4, characterized in that, The determination of whether all battery clusters have completed power balancing includes: If all battery clusters trigger the preset prohibition condition, or if the difference between the maximum value and the minimum value of the total voltage of all battery clusters is less than the preset voltage threshold, then it is determined that all battery clusters have completed power balancing. The preset prohibition conditions include conditions prohibiting charging and / or conditions prohibiting discharging.

6. A controller, characterized in that, It includes a processor and a memory, the memory being used to store computer programs, and the processor being used to call and run the computer programs stored in the memory to perform the energy storage battery equalization management method as described in any one of claims 1 to 5.

7. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the energy storage battery equalization management method as described in any one of claims 1 to 5.

8. An energy storage system, characterized in that, Includes the controller as described in claim 6.

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