Battery cluster equalization control method and system based on multi-cluster parallel connection, and medium

Abstract

The invention relates to the technical field of energy storage systems, particularly provides a battery cluster equalization control method and system based on multi-cluster parallel connection and a medium, and aims to solve the technical problem of insufficient equalization precision caused by difficulty in effectively inhibiting circulating current in an existing method. In order to achieve the purpose, the battery cluster balance control method based on multi-cluster parallel connection comprises the steps that first operation state information of each battery cluster is acquired; judging the current running state of the energy storage system based on the running state information of each battery cluster; determining a state identification bit of each battery cluster according to the current operation state and the operation state information of the energy storage system; determining the equalization time of the battery cluster needing to be equalized based on the operation state information and the state identification bit; judging whether the energy storage system enters a static state or not based on the second operation state information of each battery cluster; if yes, the battery clusters needing to be balanced are controlled to execute static balancing operation according to the state identification bit and the balancing time, the voltage difference between the battery clusters is eliminated, and cluster merging circulation is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage systems, and specifically provides a battery cluster equalization control method and system based on multi-cluster parallel connection and a medium. BACKGROUND

[0002] With the requirement of energy storage scale in new energy power station, power grid frequency modulation and other scenarios jumping from kilowatt-hour level to megawatt-hour or even hundred megawatt-hour level, the capacity of a single battery cluster cannot meet the requirement. By connecting multiple standardized battery clusters in parallel on the DC side, a super large capacity energy storage system can be flexibly and economically combined like building blocks, and the system redundancy reliability is improved. However, this architecture also brings key technical challenges such as inter-cluster circulating current and consistency management.

[0003] The existing solutions mostly rely on equalization during charging and discharging. Such methods have a blind area in the key working condition of long time static state of the system, and cannot effectively suppress circulating current, resulting in insufficient equalization accuracy. Therefore, there is an urgent need for a new equalization strategy that can accurately act in a static state and fundamentally control the circulating current problem. SUMMARY

[0004] In order to overcome the above defects, the present application is proposed to solve or at least partially solve the technical problem that the existing method cannot effectively suppress circulating current, resulting in insufficient equalization accuracy. The present application provides a battery cluster equalization control method and system based on multi-cluster parallel connection and a medium.

[0005] In a first aspect, the present application provides a battery cluster equalization control method based on multi-cluster parallel connection, applied to an energy management system, the method comprising:

[0006] obtaining first running state information of each battery cluster;

[0007] determining the current running state of the energy storage system based on the running state information of each battery cluster;

[0008] determining the state identification bit of each battery cluster according to the current running state of the energy storage system and the running state information;

[0009] determining the equalization time of the battery cluster that needs to perform equalization based on the first running state information and the state identification bit;

[0010] determining whether the energy storage system enters a static state based on second running state information of each battery cluster;

[0011] If yes, controlling the battery cluster that needs to perform equalization to perform static equalization operation according to the state identification bit and the equalization time.

[0012] In one embodiment of the battery cluster equalization control method based on multi-cluster parallel connection in this application, the current operating state of the energy storage system includes charging state, discharging state and quiescent state; the operating state information includes the current of the battery cluster; the state identifier includes a first identifier and a second identifier.

[0013] The step of determining the status identifier bits of each battery cluster based on the current operating status of the energy storage system and the operating status information includes:

[0014] When the current operating state of the energy storage system is the discharge state, it is determined whether the difference between the current of the battery cluster and the average value of the cluster current is greater than a first preset threshold. If so, the state flag of the battery cluster is determined to be the first flag; otherwise, it is the second flag.

[0015] When the current operating state of the energy storage system is charging, it is determined whether the difference between the current of the battery cluster and the average value of the cluster current is less than a second preset threshold. If so, the state flag of the battery cluster is determined to be the first flag; otherwise, it is the second flag.

[0016] When the energy storage system is currently in a static state, it is determined whether the current of the battery cluster is positive. If it is, the status flag of the battery cluster is set as the first flag; otherwise, it is set as the second flag.

[0017] In one embodiment of the battery cluster equalization control method based on multi-cluster parallel connection in this application, the first operating state information of each battery cluster includes the cluster state of charge and total voltage of each battery cluster.

[0018] The step of determining the equalization time of the battery clusters requiring equalization based on the first operating status information and the status identifier bit includes:

[0019] The battery clusters that need to be balanced are determined based on the status flag bits;

[0020] The equalization current of the battery clusters that need to be equalized is determined based on the total voltage of the battery clusters.

[0021] The difference in the state of charge of the battery clusters that needs to be balanced is determined based on the cluster state of charge of the battery clusters.

[0022] Obtain the rated capacity of the battery cluster;

[0023] The equalization time for the battery clusters requiring equalization is determined based on the equalization current, the difference in state of charge of the clusters, and the rated capacity.

[0024] In one embodiment of the battery cluster equalization control method based on multi-cluster parallel connection in this application, the status flag bit includes a first flag bit and a second flag bit;

[0025] The step of determining the battery clusters that need to be balanced based on the status flag bit includes: determining the corresponding battery clusters that need to be balanced when the status flag bit is the first flag bit; and determining the corresponding battery clusters that do not need to be balanced when the status flag bit is the second flag bit.

[0026] In one embodiment of the battery cluster equalization control method based on multi-cluster parallel connection, determining the equalization time of the battery cluster to be equalized based on the equalization current, the cluster state of charge difference, and the rated capacity includes: using the ratio of the product of the cluster state of charge difference and the rated capacity to the equalization current as the equalization time of the battery cluster to be equalized.

[0027] In one embodiment of the battery cluster equalization control method based on multi-cluster parallel connection of this application, the step of determining whether the energy storage system is in a static state based on the second operating state information of each battery cluster includes:

[0028] The total bus current is determined based on the second operating status information of each battery cluster.

[0029] When the absolute value of the total current of the bus is less than the preset current threshold, the energy storage system is determined to be in a static state.

[0030] In one embodiment of the battery cluster equalization control method based on multi-cluster parallel connection in this application, the method further includes:

[0031] Obtain the terminal temperature and fault status of the battery cluster undergoing static equalization;

[0032] Determine whether the terminal temperature of the battery cluster is greater than a first preset temperature threshold and whether the fault state is a preset state;

[0033] If so, the static equalization operation for the battery cluster is terminated.

[0034] In one embodiment of the battery cluster equalization control method based on multi-cluster parallel connection in this application, the method further includes:

[0035] After the terminal temperature of the battery cluster drops to a second preset temperature threshold, a static equalization operation is performed on the battery cluster, wherein the second preset temperature threshold is less than the first preset temperature threshold.

[0036] In a second aspect, an energy storage system is provided, the energy storage system including an energy management system, the energy management system comprising:

[0037] At least one processor;

[0038] And, a memory communicatively connected to the at least one processor;

[0039] The memory stores a computer program, which, when executed by the at least one processor, implements the aforementioned battery cluster equalization control method based on multi-cluster parallel connection.

[0040] In a third aspect, a computer-readable storage medium is provided, wherein a plurality of program codes are stored therein, the program codes being adapted to be loaded and executed by a processor to perform the battery cluster equalization control method based on multi-cluster parallel connection as described in any of the preceding claims.

[0041] The above-described technical solutions of this application have at least one or more of the following beneficial effects:

[0042] The battery cluster equalization control method based on multi-cluster parallel connection in this application includes: acquiring the first operating state information of each battery cluster; determining the current operating state of the energy storage system based on the operating state information of each battery cluster; determining the state flag bit of each battery cluster according to the current operating state and operating state information of the energy storage system; determining the equalization time of the battery clusters that need to be equalized based on the operating state information and the state flag bit; determining whether the energy storage system has entered a static state based on the second operating state information of each battery cluster; if so, controlling the battery clusters that need to be equalized to perform static equalization operation according to the state flag bit and the equalization time. By accurately identifying the current operating state of the energy storage system and performing targeted static equalization, the method utilizes the stable parameter characteristics of battery clusters in the static state, improves the accuracy of equalization control, effectively reduces the parameter differences between battery clusters, avoids the impact of the weakest link effect on the capacity and lifespan of the energy storage system, and reduces the circulating current impact when battery clusters are connected in parallel; at the same time, static equalization is completed during non-working periods, without affecting the normal charging and discharging function of the energy storage system, taking into account both system operating efficiency and safety, and extending the overall cycle life of the battery clusters and the stability of the energy storage system. Attached Figure Description

[0043] The disclosure of this application will become more readily understood with reference to the accompanying drawings. It will be readily understood by those skilled in the art that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of this application. Furthermore, similar numbers in the drawings are used to denote similar components, wherein:

[0044] Figure 1 This is a schematic diagram of the energy storage system in one embodiment of this application;

[0045] Figure 2 This is a schematic diagram of the main process of a battery cluster equalization control method based on multiple parallel clusters in one embodiment of this application;

[0046] Figure 3 This is a schematic diagram of the main structure of a battery cluster equalization control device based on multiple parallel clusters in one embodiment of this application;

[0047] Figure 4 This is a schematic diagram of the energy management system in one embodiment of this application. Detailed Implementation

[0048] Some embodiments of this application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of this application and are not intended to limit the scope of protection of this application.

[0049] In the description of this application, "module" and "processor" can include hardware, software, or a combination of both. A module can include hardware circuitry, various suitable sensors, communication ports, memory, and can also include software components, such as program code, or a combination of software and hardware. A processor can be a central processing unit, microprocessor, image processor, digital signal processor, or any other suitable processor. The processor has data and / or signal processing capabilities. The processor can be implemented in software, in hardware, or a combination of both. Non-transitory computer-readable storage media includes any suitable medium capable of storing program code, such as magnetic disks, hard disks, optical disks, flash memory, read-only memory, random access memory, etc. The term "A and / or B" means all possible combinations of A and B, such as only A, only B, or A and B. The terms "at least one A or B" or "at least one of A and B" have a similar meaning to "A and / or B" and can include only A, only B, or A and B. The singular terms "a" or "this" can also include plural forms.

[0050] Current traditional methods typically employ active or passive balancing schemes under charging and discharging scenarios to achieve battery cluster balancing. However, these methods have poor adaptability in static conditions and suffer from inaccurate balancing. Therefore, this application proposes a battery cluster balancing control method, system, and dielectric based on multiple parallel battery clusters.

[0051] Next, we will first describe in detail the specific structure of the energy storage system in this application.

[0052] like Figure 1As shown, the energy storage system includes multiple parallel battery clusters, an energy management system (EMS), an energy storage converter (PCS), and a DC bus. Multiple battery clusters are connected to the energy storage converter via the DC bus. Each battery cluster contains a battery management unit (BMU) and a cluster-level battery management unit (BCMU). Each battery cluster has a resistor R and a switch SW for balancing, as well as a Hall sensor (HALL) and a temperature monitoring component (Temp) for current monitoring. The energy management system interacts with the energy storage converter and the cluster-level battery management units of each battery cluster via a communication link, and simultaneously sends control signals to the battery clusters to achieve functions such as monitoring the operating status and balancing management of the entire energy storage system. It should be understood that, in addition to using Hall sensors (HALL) to monitor the current of the battery clusters, other sensors can also be used to monitor the current; there are no specific limitations, as long as the monitoring of the current in the circuit can be achieved.

[0053] See appendix Figure 2 , Figure 2 This is a schematic flowchart of the main steps of a battery cluster equalization control method based on multiple parallel battery clusters according to an embodiment of this application.

[0054] like Figure 2 As shown, the battery cluster equalization control method based on multi-cluster parallel connection in this application embodiment mainly includes the following steps S10-S60.

[0055] Step S10: Obtain the first operating status information of each battery cluster.

[0056] A battery cluster is an independent energy storage unit formed by connecting multiple battery cells in series and in parallel. It is the core component of a large-scale parallel energy storage system and can realize the storage and release of electrical energy.

[0057] The first operating status information refers to the dynamic parameters generated by the battery cluster during the current operation, specifically including the cluster state of charge (SOC), and may also cover data such as the total voltage, current, and terminal temperature of the battery cluster.

[0058] Step S20: Determine the current operating status of the energy storage system based on the operating status information of each battery cluster.

[0059] The current operating state of an energy storage system includes charging / discharging state and static state.

[0060] The charging and discharging state is the working state of an energy storage system when it is receiving electrical energy (charging) or outputting electrical energy (discharging), which is different from the static state when there is no energy input or output.

[0061] The static state is the standby state of the energy storage system when it is not charging or discharging. At this time, the battery cluster has no energy input or output, and parameters such as voltage and SOC are in a stable state.

[0062] Step S30: Determine the status identifier bit of each battery cluster based on the current operating status of the energy storage system and the operating status information.

[0063] The status flag bits are binary bits used to indicate whether the battery clusters need to be balanced. Specifically, they include a first flag bit and a second flag bit, where the first flag bit is 1 and the second flag bit is 0.

[0064] Step S40: Determine the equalization time of the battery clusters that need to be equalized based on the first operating status information and the status identifier bit.

[0065] Equalization time is the specific duration used to complete energy regulation, calculated based on the degree of difference between the battery cluster that needs to be equalized and the target parameters.

[0066] Step S50: Determine whether the energy storage system has entered a static state based on the second operating state information of each battery cluster.

[0067] The second operating status information refers to the dynamic parameters generated by the battery cluster during its current operation, specifically including the cluster's state of charge (SOC), and may also cover data such as the battery cluster's total voltage, current, and terminal temperature. It should be noted that the first and second operating status information differ during charging and discharging; however, in a static state, the second operating status information can be the same as the first operating status information.

[0068] Step S60: Perform static balancing operation on the battery clusters that need to be balanced according to the status flag bit and the balancing time control.

[0069] Static balancing is a balancing control performed when the energy storage system is at rest. Specifically, it achieves uniformity of parameters among the battery clusters through energy transfer or adjustment.

[0070] Based on steps S10-S60 above, firstly, the first operating state information of each battery cluster is obtained; the current operating state of the energy storage system is determined based on the operating state information of each battery cluster; the status flag of each battery cluster is determined according to the current operating state and operating state information of the energy storage system; the balancing time of the battery clusters that need to be balanced is determined based on the operating state information and status flag; the second operating state information of each battery cluster is used to determine whether the energy storage system has entered a static state; if so, the static balancing operation of the battery clusters that need to be balanced is controlled according to the status flag and the balancing time. By accurately identifying the current operating state of the energy storage system and performing targeted static balancing, the stability of battery cluster parameters in the static state is utilized, improving the accuracy of balancing control, effectively reducing the parameter differences between battery clusters, avoiding the impact of the weakest link effect on the capacity and lifespan of the energy storage system, and reducing the circulating current impact when battery clusters are connected; at the same time, static balancing is completed during non-working periods, without affecting the normal charging and discharging function of the energy storage system, taking into account both system operating efficiency and safety, extending the overall cycle life of the battery clusters and the stability of the energy storage system.

[0071] The following provides further explanation of steps S10 to S60.

[0072] Specifically, in step S10 above, the cluster-level battery management unit (BCMU) of each battery cluster collects the total voltage (determined by the total output voltage of the individual battery cells connected in series), current (monitored by a Hall sensor), and temperature (collected by a temperature monitoring component) of the battery cluster, and uploads this data to the energy management system (EMS) via a communication link. This allows the EMS to acquire operational status information such as the total voltage, current, and terminal temperature of the battery cluster. Furthermore, the energy management system also obtains the fault status of each battery cluster from the BCMU via the communication link, such as whether the battery cluster is overvoltage, undervoltage, or overcurrent.

[0073] Each battery cluster's cluster-level battery management unit (BCMU) determines the cluster state of charge (SOC) based on the total voltage and current data of the battery cluster, combined with the capacity characteristic curve of the battery cluster, using the ampere-hour integration method or combining the open-circuit voltage-SOC correspondence, and then uploads the calculation results to the energy management system.

[0074] The above is a further explanation of step S10. Step S20 will be further explained below.

[0075] Specifically, regarding step S20 above, the energy management system reads the current operating command of the energy storage converter in real time through the communication link with the energy storage converter. This command clarifies whether the energy storage converter is in charging or discharging mode, and is one of the key bases for determining the system's charging and discharging status. When current is detected flowing from the external load to the battery cluster, and the energy storage converter's operating command is a charging command, it indicates that electrical energy is being stored in the battery cluster through the energy storage converter, thus determining that the energy storage system is in a charging state. When current is detected flowing from the battery cluster to the external load, and the energy storage converter's operating command is a discharging command, it indicates that the electrical energy stored in the battery cluster is being supplied to the external load through the energy storage converter, thus determining that the energy storage system is in a discharging state.

[0076] The energy management system calculates the total DC bus current of the energy storage system based on the current of each battery cluster. Specifically, if multiple battery clusters are connected to the grid, the total bus current is the algebraic sum of the currents of each connected battery cluster; if all battery clusters are off-grid, the total bus current is 0. When the absolute value of the total bus current is less than a preset current threshold, it indicates that the energy storage system is neither discharging to an external load nor receiving charging energy from an external source. The battery clusters and the entire system are in an idle state with no energy flow, thus indicating that the energy storage system is in a static state.

[0077] The above is a further explanation of step S20. Step S30 will be further explained below.

[0078] In a specific embodiment of the battery cluster equalization control method based on multi-cluster parallel connection in this application, the current operating state of the energy storage system includes a charging state, a discharging state, and a quiescent state; the operating state information includes the current of the battery cluster; the state identifier includes a first identifier and a second identifier; determining the state identifier of each battery cluster based on the current operating state of the energy storage system and the operating state information includes: when the current operating state of the energy storage system is a discharging state, determining whether the difference between the current of the battery cluster and the average value of the cluster current is greater than a first preset threshold; if so, determining the state identifier of the battery cluster as the first identifier, otherwise as the second identifier; when the current operating state of the energy storage system is a charging state, determining whether the difference between the current of the battery cluster and the average value of the cluster current is less than a second preset threshold; if so, determining the state identifier of the battery cluster as the first identifier, otherwise as the second identifier; when the current operating state of the energy storage system is a quiescent state, determining whether the current of the battery cluster is positive; if so, determining the state identifier of the battery cluster as the first identifier, otherwise as the second identifier.

[0079] The first and second preset thresholds are pre-set values, which can be adjusted adaptively according to the actual scenario, and no specific limitations are imposed on them.

[0080] Specifically, when the sum of the currents of all parallel battery clusters in the energy storage system (ΣI_cluster_x) exceeds the total bus current and reaches the circulating current threshold (I_circul_thre), it indicates that circulating current exists, i.e., |ΣI_cluster_x-I_total|>I_circul_thre. The average value of the currents of the N clusters currently connected to the energy storage system is obtained as I_avg = I_total / N.

[0081] In the discharge state, if the current of the battery cluster is significantly greater than the average value of the cluster current, it indicates that the battery cluster is not only discharging to the load, but also charging other clusters. The voltage of this battery cluster is high, and it is the source of circulating current. The status flag bit of this battery cluster is recorded as 1 (first flag bit). If the current of the battery cluster is significantly less than the average value of the cluster current, it indicates that this cluster cannot output normal discharge current. The voltage of this cluster is low, and the status flag bit of this battery cluster remains at 0 (second flag bit).

[0082] During charging, if the current of a battery cluster is significantly greater than the average value of the cluster current, it indicates that this battery cluster is not only obtaining charging current from the energy storage converter, but also obtaining circulating current from other clusters. The voltage of this cluster is relatively low, and the status flag bit of this battery cluster remains at 0 (second flag bit). If the current of a battery cluster is significantly less than the average value of the cluster current, it indicates that this cluster cannot receive normal charging current. The voltage of this cluster is high, and it is the source of circulating current. The status flag bit of this battery cluster is recorded as 1 (first flag bit).

[0083] When the battery cluster is in a static state and its state of charge is in the middle region (10% < SOC < 90%), the total current of the bus is 0. The currents I_cluster_1, I_cluster_2, ..., I_cluster_N of each parallel battery cluster are obtained. According to the principle that charging is negative and discharging is positive, if the current reading of a certain battery cluster is continuously positive (outflow), it means that the battery cluster is discharging to the energy storage system. The voltage of this cluster is relatively high and it is the source of circulating current. The status flag of this battery cluster is recorded as 1 (first flag). If it is continuously negative (inflow), it means that it is being charged. The voltage of this cluster is low, and the status flag of this battery cluster is kept at 0 (second flag).

[0084] The above is a further explanation of step S30. Step S40 will be further explained below.

[0085] Specifically, step S40 can be implemented through steps S401 to S405.

[0086] Step S401: Determine the battery clusters that need to be balanced based on the status flag bits.

[0087] In one specific embodiment, the status identifier bit includes a first identifier bit and a second identifier bit; determining the battery cluster that needs to be balanced based on the status identifier bit includes: determining the corresponding battery cluster that needs to be balanced when the status identifier bit is the first identifier bit; and determining the corresponding battery cluster that does not need to be balanced when the status identifier bit is the second identifier bit.

[0088] Specifically, when the status flag of a battery cluster is the first flag (i.e., 1), the corresponding battery cluster is determined to be a battery cluster that needs to be balanced; when the status flag of a battery cluster is the second flag (i.e., 0), the corresponding battery cluster is determined to be a battery cluster that does not need to be balanced.

[0089] Step S402: Determine the balancing current of the battery clusters that need to be balanced based on the total voltage of the battery clusters.

[0090] Specifically, the balancing current for the battery clusters requiring balancing can be determined based on the ratio of the total voltage of the battery cluster to the balancing resistance. For example, the formula for calculating the balancing current can be I_balance_x = V_cluster_x / R_balance, where V_cluster_x is the total voltage of the battery cluster and R_balance is the balancing resistance.

[0091] Step S403: Determine the difference in the state of charge of the battery clusters that need to be balanced based on the state of charge of the battery clusters.

[0092] Specifically, first, determine the average cluster state of charge (SOC) of the N battery clusters currently connected in parallel to the energy storage system. The specific calculation formula is: cluster SOC_avg = ΣSOC_cluster_x / N. Then, the absolute value of the difference between the battery cluster that needs to be balanced and the average cluster SOC (cluster SOC difference) is: ΔSOC_cluster_x = |SOC_cluster_x – SOC_avg|.

[0093] Step S404: Obtain the rated capacity of the battery cluster.

[0094] Rated capacity refers to the nominal total amount of electricity that a battery cluster can safely and stably release under specified standard conditions (including standard charge and discharge current, temperature, termination voltage, etc.), which is determined by the design.

[0095] Step S405: Determine the equalization time of the battery clusters to be equalized based on the equalization current, the cluster state of charge difference, and the rated capacity.

[0096] In one specific embodiment, determining the balancing time of the battery cluster to be balanced based on the balancing current, the cluster state of charge difference, and the rated capacity includes: using the ratio of the product of the cluster state of charge difference and the rated capacity to the balancing current as the balancing time of the battery cluster to be balanced.

[0097] Specifically, the product of the cluster state of charge difference and the rated capacity, and the ratio of this product to the balancing current, is used as the balancing time for the battery cluster that needs to be balanced. The specific calculation formula can be expressed as: T_balance_x=ΔSOC_cluster_x×Q_cluster_x / I_balance_x, where Q_cluster_x is the rated capacity of the battery cluster.

[0098] The above is a further explanation of step S40. Step S50 will be further explained below.

[0099] Specifically, step S50 can be implemented through steps S501 to S502.

[0100] Step S501: Determine the total bus current based on the second operating status information of each battery cluster.

[0101] Specifically, the energy management system calculates the total current of the energy storage system's DC bus by combining the current of each battery cluster (monitored in real time by Hall sensors configured in each cluster) with the grid-connected / off-grid status of the clusters. Furthermore, if multiple battery clusters are in a grid-connected state, the total bus current is the algebraic sum of the currents of each grid-connected cluster; if all battery clusters are in an off-grid state, the total bus current is 0.

[0102] Step S502: When the absolute value of the total current of the bus is less than the preset current threshold, the energy storage system is determined to be in a static state.

[0103] The preset current threshold is a small current value set according to the rated power of the energy storage system, the characteristics of the battery cluster, and the operational safety requirements. It is used to distinguish between states with energy input / output and states without energy input / output. For example, any current between 0.2A and 0.5A can be used as an example of the preset current threshold.

[0104] Specifically, when the absolute value of the total bus current is less than the preset current threshold, it indicates that the energy storage system is neither discharging to the external load nor receiving charging energy from the outside. Each battery cluster and the entire system are in an idle state with no energy flow, and the energy storage system is judged to be in a static state.

[0105] The system accurately determines the static state of the energy storage system by combining the total bus current with a preset threshold. The judgment logic is simple, efficient, and has a fast response speed.

[0106] The above is a further explanation of step S50. Step S60 will be further explained below.

[0107] Specifically, when the energy storage system enters a static state, the energy management system controls the contactors of the battery clusters ( Figure 1 The closing of Q) cuts off the battery cluster whose status flag is the first flag, causing it to disconnect from the bus, and controls the closing of the equalization resistor ( Figure 1 The switch (R) in the middle Figure 1 In the SW section, equalization is initiated for the battery clusters that need to be balanced according to the calculated equalization time T_balance_x.

[0108] By first acquiring the battery cluster operating status information and determining the energy storage system operating status, and then accurately determining the status identifier and equalization time of each cluster, targeted static equalization is performed after the system enters a static state. This achieves accurate selection of equalization targets and matching of equalization time, avoiding energy loss and equipment damage caused by ineffective equalization. It also ensures equalization efficiency and effectiveness in scenarios where there is no external energy output in a static state, effectively reducing the differences in voltage and state of charge between clusters to eliminate circulating current hazards. At the same time, it takes into account the safety, stability and battery cluster lifespan of the energy storage system, significantly improving the overall operational reliability and economy of the parallel energy storage system.

[0109] In one specific embodiment of the battery cluster equalization control method based on multi-cluster parallel connection in this application, the method further includes: acquiring the terminal temperature and fault status of the battery cluster performing static equalization; determining whether the terminal temperature of the battery cluster is greater than a first preset temperature threshold and whether the fault status is a preset status; if so, terminating the static equalization operation for the battery cluster.

[0110] The first preset temperature threshold is the critical temperature value set by the pre-defined heat resistance limit of the equalization circuit.

[0111] Fault status refers to the undervoltage, overvoltage, overcurrent, and other fault states of the battery cluster.

[0112] The preset state refers to the state in which the battery cluster experiences a pre-set fault state during the equalization process and lasts for a certain period of time.

[0113] Specifically, during the static balancing process of the battery cluster, the energy management system continuously collects the terminal temperature of the target battery cluster being balanced in real time. Then, it compares the collected terminal temperature with a preset temperature threshold. If the terminal temperature exceeds the preset temperature threshold, or if the battery cluster experiences a preset fault state during the balancing process and this state persists for a certain period of time, it means that there is an overheating risk and a preset fault during the balancing process. The energy storage system then immediately issues an instruction to terminate the static balancing operation of the battery cluster to prevent the risk from escalating.

[0114] By monitoring the terminal temperature and fault status in real time during the equalization process and setting safety thresholds for risk assessment, the system can quickly identify potential overheating hazards during the equalization process and terminate the operation in a timely manner. This effectively avoids thermal runaway and other preset faults caused by over-equalization of the battery cluster, ensuring the operational safety of the battery cluster and energy storage system. It further improves the reliability and safety of static equalization control and extends the service life of the battery cluster.

[0115] In one embodiment of the battery cluster equalization control method based on multi-cluster parallel connection in this application, the method further includes: after the terminal temperature of the battery cluster drops to a second preset temperature threshold, continuing to perform static equalization operation on the battery cluster, wherein the second preset temperature threshold is less than the first preset temperature threshold.

[0116] The second preset temperature threshold refers to the critical temperature value for the safe restart of static equalization of the battery cluster. It is lower than the first preset temperature threshold to ensure that there is no risk of overheating during restart equalization.

[0117] Specifically, after the terminal temperature of the battery cluster is detected to drop to the second preset temperature threshold, a static equalization operation is performed on the battery cluster again.

[0118] It should be noted that although the steps in the above embodiments are described in a specific order, those skilled in the art will understand that in order to achieve the effect of this application, different steps do not necessarily have to be executed in such an order. They can be executed simultaneously (in parallel) or in other orders, and these variations are all within the scope of protection of this application.

[0119] Furthermore, this application also provides a battery cluster equalization control device based on multiple clusters in parallel.

[0120] See appendix Figure 3 , Figure 3 This is a main structural block diagram of a battery cluster equalization control device based on multiple parallel clusters according to an embodiment of this application.

[0121] like Figure 3 As shown, the battery cluster equalization control device based on multi-cluster parallel connection in this application embodiment mainly includes an acquisition module 11, a first judgment module 12, a first determination module 13, a second determination module 14, a second judgment module 15, and an equalization module 16. In some embodiments, one or more of the acquisition module 11, the first judgment module 12, the first determination module 13, the second determination module 14, the second judgment module 15, and the equalization module 16 can be combined into a single module.

[0122] In some embodiments, the acquisition module 11 can be configured to acquire the first operating status information of each battery cluster.

[0123] The first judgment module 12 can be configured to judge the current operating status of the energy storage system based on the operating status information of each battery cluster.

[0124] The first determining module 13 can be configured to determine the status identifier bit of each battery cluster based on the current operating status of the energy storage system and the operating status information.

[0125] The second determining module 14 can be configured to determine the balancing time of the battery clusters that need to be balanced based on the operating status information and the status flag bit.

[0126] The second judgment module 15 can be configured to determine whether the energy storage system has entered a static state based on the second operating status information of each battery cluster.

[0127] The balancing module 16 can be configured to control the battery clusters that need to be balanced to perform static balancing operations when the energy storage system enters a static state, based on the status flag bit and the balancing time.

[0128] In one implementation, a description of the specific functions can be found in steps S10-S60.

[0129] The aforementioned battery cluster equalization control device based on multi-cluster parallel connection is used to perform Figure 2 The embodiments of the battery cluster equalization control method based on multi-cluster parallel connection shown are similar in technical principle, technical problem solved and technical effect. Those skilled in the art can clearly understand that, for the sake of convenience and brevity, the specific working process and related descriptions of the battery cluster equalization control device based on multi-cluster parallel connection can be found in the embodiments of the battery cluster equalization control method based on multi-cluster parallel connection, and will not be repeated here.

[0130] Furthermore, it should be understood that since the various modules are only provided to illustrate the functional units of the device described in this application, the physical devices corresponding to these modules may be the processor itself, or a part of the processor's software, hardware, or a combination of both. Therefore, the number of modules shown in the figures is merely illustrative.

[0131] Those skilled in the art will understand that the various modules in the device can be adaptively split or combined. Such splitting or combining of specific modules will not cause the technical solution to deviate from the principles of this application; therefore, the technical solutions after splitting or combining will fall within the protection scope of this application.

[0132] Those skilled in the art will understand that all or part of the processes in the method of the above-described embodiment 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 method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable file, or some intermediate form. The computer-readable storage medium can include any entity or device capable of carrying the computer program code, a medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory, a random access memory, an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0133] Furthermore, this application also provides an energy storage system, the energy storage system including an energy management system, the energy management system including:

[0134] At least one processor;

[0135] And, a memory communicatively connected to the at least one processor;

[0136] The memory stores a computer program that, when executed by the at least one processor, implements the aforementioned battery cluster equalization control method based on multi-cluster parallel connection. See also... Figure 4 As shown, Figure 4 The structure of an energy management system, including a processor 100 and a memory 200, is illustrated by way of example.

[0137] Furthermore, this application also provides a computer-readable storage medium. In one embodiment of the computer-readable storage medium according to this application, the computer-readable storage medium can be configured to store a program that executes the battery cluster equalization control method based on multi-cluster parallel connection described in the above-described method embodiments. This program can be loaded and run by a processor to implement the above-described battery cluster equalization control method based on multi-cluster parallel connection. For ease of explanation, only the parts related to the embodiments of this application are shown; for specific technical details not disclosed, please refer to the method section of the embodiments of this application. The computer-readable storage medium can be a memory device formed by various electronic devices. Optionally, in the embodiments of this application, the computer-readable storage medium is a non-transitory computer-readable storage medium.

[0138] The technical solution of this application has been described in conjunction with the specific embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.

Claims

1. A battery cluster equalization control method based on multi-cluster parallel connection, applied to an energy management system, characterized in that, The method includes: Obtain the initial operating status information of each battery cluster; The current operating status of the energy storage system is determined based on the operating status information of each battery cluster. The status identifier bits of each battery cluster are determined based on the current operating status of the energy storage system and the operating status information. The equalization time for the battery clusters that need to be equalized is determined based on the first operating status information and the status identifier bit. Determine whether the energy storage system has entered a static state based on the second operating status information of each battery cluster; If so, the battery clusters that need to be balanced according to the status flag bit and the balancing time control shall perform static balancing operation.

2. The battery cluster equalization control method based on multi-cluster parallel connection according to claim 1, characterized in that, The current operating status of the energy storage system includes charging status, discharging status, and quiescent status; the operating status information includes the current of the battery cluster; the status identifier includes a first identifier and a second identifier. The step of determining the status identifier bits of each battery cluster based on the current operating status of the energy storage system and the operating status information includes: When the current operating state of the energy storage system is the discharge state, it is determined whether the difference between the current of the battery cluster and the average value of the cluster current is greater than a first preset threshold. If so, the state flag of the battery cluster is determined to be the first flag; otherwise, it is the second flag. When the current operating state of the energy storage system is charging, it is determined whether the difference between the current of the battery cluster and the average value of the cluster current is less than a second preset threshold. If so, the state flag of the battery cluster is determined to be the first flag; otherwise, it is the second flag. When the energy storage system is currently in a static state, it is determined whether the current of the battery cluster is positive. If it is, the status flag of the battery cluster is set as the first flag; otherwise, it is set as the second flag.

3. The battery cluster equalization control method based on multi-cluster parallel connection according to claim 1, characterized in that, The first operating status information of each battery cluster includes the cluster state of charge and total voltage of each battery cluster; The step of determining the equalization time of the battery clusters requiring equalization based on the first operating status information and the status identifier bit includes: The battery clusters that need to be balanced are determined based on the status flag bits; The equalization current of the battery clusters that need to be equalized is determined based on the total voltage of the battery clusters. The difference in the state of charge of the battery clusters that needs to be balanced is determined based on the cluster state of charge of the battery clusters. Obtain the rated capacity of the battery cluster; The equalization time for the battery clusters requiring equalization is determined based on the equalization current, the difference in state of charge of the clusters, and the rated capacity.

4. The battery cluster equalization control method based on multi-cluster parallel connection according to claim 3, characterized in that, The status identifier includes a first identifier and a second identifier; The step of determining the battery clusters that need to be balanced based on the status flag bit includes: determining the corresponding battery clusters that need to be balanced when the status flag bit is the first flag bit; When the status flag is the second flag, the corresponding battery cluster is determined to be a battery cluster that does not require equalization.

5. The battery cluster equalization control method based on multi-cluster parallel connection according to claim 3, characterized in that, The step of determining the balancing time of the battery clusters to be balanced based on the balancing current, the cluster state of charge difference, and the rated capacity includes: using the ratio of the product of the cluster state of charge difference and the rated capacity to the balancing current as the balancing time of the battery clusters to be balanced.

6. The battery cluster equalization control method based on multi-cluster parallel connection according to claim 1, characterized in that, The step of determining whether the energy storage system is in a static state based on the second operating status information of each battery cluster includes: The total bus current is determined based on the second operating status information of each battery cluster. When the absolute value of the total current of the bus is less than the preset current threshold, the energy storage system is determined to be in a static state.

7. The battery cluster equalization control method based on multi-cluster parallel connection according to claim 1, characterized in that, The method further includes: Obtain the terminal temperature and fault status of the battery cluster undergoing static equalization; Determine whether the terminal temperature of the battery cluster is greater than a first preset temperature threshold and whether the fault state is a preset state; If so, the static equalization operation for the battery cluster is terminated.

8. The battery cluster equalization control method based on multi-cluster parallel connection according to claim 7, characterized in that, The method further includes: after the terminal temperature of the battery cluster drops to a second preset temperature threshold, continuing to perform static equalization operation on the battery cluster, wherein the second preset temperature threshold is less than the first preset temperature threshold.

9. An energy storage system, characterized in that, The energy storage system includes an energy management system, which includes: At least one processor; And, a memory communicatively connected to the at least one processor; The memory stores a computer program, which, when executed by the at least one processor, implements the battery cluster equalization control method based on multiple clusters in parallel as described in any one of claims 1 to 8.

10. A computer-readable storage medium storing a plurality of program codes, characterized in that, The program code is adapted to be loaded and run by a processor to perform the battery cluster equalization control method based on multi-cluster parallel connection as described in any one of claims 1 to 8.

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