Battery cluster parallel connection method and device and electronic equipment

Abstract

The invention provides a battery cluster parallel connection method and device and electronic equipment, and the method comprises the steps: obtaining a first bus voltage and a first bus current of an energy storage system and a voltage of a target battery cluster to be connected to a bus of the energy storage system under the condition that the battery cluster needs to be connected to the bus of the energy storage system; and when the difference value between the first bus voltage and the voltage is smaller than or equal to a first difference value threshold value and the first bus current is smaller than or equal to a preset current threshold value, controlling the target battery cluster to be merged into a bus of the energy storage system, so that safe parallel connection of the battery clusters can be realized.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic energy storage equipment technology, and in particular relates to a method, device and electronic equipment for parallel connection of battery clusters. Background Technology

[0002] In the construction of large-scale energy storage power stations, multiple battery clusters are often connected in parallel and then connected to a high-power energy storage converter (PCS) to increase system capacity and power. The existing solution is to directly connect the battery clusters in parallel, but this solution may generate a large inrush current, damaging the contactor and the battery cells. Summary of the Invention

[0003] This application provides a method, apparatus, and electronic device for parallel connection of battery clusters, which can achieve safe parallel connection of battery clusters.

[0004] In a first aspect, embodiments of this application provide a method for parallel connection of battery clusters, including:

[0005] When it is necessary to connect a battery cluster to the bus of an energy storage system, the first bus voltage, the first bus current, and the voltage of the target battery cluster to be connected to the bus of the energy storage system are obtained. When the difference between the first bus voltage and the voltage is less than or equal to a first difference threshold and the first bus current is less than or equal to a preset current threshold, the target battery cluster is controlled to be connected to the bus of the energy storage system.

[0006] In some embodiments, the method further includes: Obtain the charging and discharging status information of the energy storage system; When the charging and discharging condition information is in the discharging condition, the battery clusters with voltages lower than the first bus voltage are identified as the target battery clusters to be connected to the bus of the energy storage system, and the connection order is determined based on the voltage of the target battery clusters from high to low. When the charging / discharging condition information is in the charging condition, the battery clusters with voltages greater than the first bus voltage are identified as the target battery clusters to be connected to the bus of the energy storage system, and the connection order is determined based on the voltage of the target battery clusters from low to high.

[0007] In some embodiments, the method further includes: If the charging / discharging condition information indicates a discharging condition and the difference between the first bus voltage and the voltage is greater than a second difference threshold, the second bus voltage of the bus will continue to be acquired. When the difference between the second bus voltage and the voltage is greater than a first difference threshold and less than or equal to the second difference threshold, the energy storage system is subjected to voltage loop regulation so that the difference between the adjusted third bus voltage and the voltage is less than or equal to the first difference threshold. When the difference between the adjusted third bus voltage and the voltage is less than or equal to the first difference threshold, the energy storage system is controlled to perform constant voltage discharge and the second bus current of the bus is obtained. When the second bus current is less than or equal to the preset current threshold, the target battery cluster is controlled to be connected to the bus, wherein the second difference threshold is greater than the first difference threshold.

[0008] In some embodiments, the method further includes: When the charging / discharging condition information is a discharging condition, and the difference between the first bus voltage and the voltage is greater than the first difference threshold and less than or equal to the second difference threshold, the energy storage system is subjected to voltage loop regulation so that the difference between the adjusted fourth bus voltage and the voltage is less than or equal to the first difference threshold. When the difference between the adjusted fourth bus voltage and the voltage is less than or equal to the first difference threshold, the energy storage system is controlled to perform constant voltage discharge and the third bus current of the bus is obtained. When the current of the third bus is less than or equal to the preset current threshold, the target battery cluster is controlled to be connected to the bus, wherein the second difference threshold is greater than the first difference threshold.

[0009] In some embodiments, the method further includes: If the charging / discharging condition information indicates a charging condition and the difference between the first bus voltage and the voltage is greater than the third difference threshold, the fifth bus voltage of the bus will continue to be acquired. If the difference between the fifth bus voltage and the voltage is less than or equal to a third difference threshold and greater than a first difference threshold, the energy storage system is subjected to voltage loop regulation so that the difference between the adjusted sixth bus voltage and the voltage is less than or equal to a first difference threshold. If the difference between the adjusted sixth bus voltage and the voltage is less than or equal to the first difference threshold, the energy storage system is controlled to perform constant voltage charging and the fourth bus current of the bus is obtained. When the current of the fourth bus is less than or equal to the preset current threshold, the target battery cluster is controlled to be connected to the bus, wherein the third difference threshold is greater than the first difference threshold.

[0010] In some embodiments, the method further includes: When the charging / discharging condition information is a charging condition and the difference between the first bus voltage and the voltage is greater than a first difference threshold and less than or equal to a third difference threshold, the energy storage system is subjected to voltage loop regulation so that the difference between the adjusted seventh bus voltage and the voltage is less than the first difference threshold. If the difference between the adjusted seventh bus voltage and the voltage is less than or equal to the first difference threshold, the energy storage system is controlled to perform constant voltage charging, and the fifth bus current of the bus is obtained. When the current of the fifth bus is less than or equal to the preset current threshold, the target battery cluster is controlled to be connected to the bus, wherein the third difference threshold is greater than the first difference threshold.

[0011] In some embodiments, the target battery cluster is connected to the bus via a pre-charging circuit, and the target battery cluster is also connected to the bus via a main contactor circuit. The pre-charging circuit is connected in parallel with the main contactor circuit. The pre-charging circuit includes a pre-charging contactor and a pre-charging resistor. The main contactor circuit includes a main contactor. The bus that controls the connection of the target battery cluster to the energy storage system includes: Control the precharge contactor to close; Obtain the voltage difference across the pre-charging circuit; When the voltage difference across the pre-charge circuit is less than or equal to the fourth difference threshold, the main contactor is controlled to close, and the pre-charge contactor is controlled to open.

[0012] In some embodiments, the method further includes: Determine the state of charge (SOC) value of each battery cluster connected to the energy storage system; The average state of charge (SOC) value is determined based on the SOC value of each battery cluster. When the energy storage system is in a discharge state and the state of charge (SOC) value of a battery cluster is less than the first SOC threshold, the energy storage system is controlled to enter constant voltage discharge. The first SOC threshold is determined based on the average SOC value and a preset first SOC deviation threshold. When the energy storage system is in a charging state and the state of charge (SOC) value of a battery cluster is greater than the second SOC threshold, the charging current of the energy storage system is reduced or the energy storage system is controlled to enter a constant voltage charging stage. The second SOC threshold is determined based on the average SOC value and a preset second SOC deviation threshold.

[0013] Secondly, embodiments of this application provide a battery cluster parallel connection device, comprising: The first acquisition module is used to acquire the first bus voltage, the first bus current, and the voltage of the target battery cluster to be connected to the bus of the energy storage system when it is necessary to connect the battery cluster to the bus of the energy storage system. The first integration module is used to control the target battery cluster to be integrated into the bus of the energy storage system when the difference between the first bus voltage and the voltage is less than or equal to a first difference threshold and the first bus current is less than or equal to a preset current threshold.

[0014] Thirdly, embodiments of this application provide an electronic device, 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 method described in any of the above-mentioned embodiments.

[0015] Fourthly, embodiments of this application provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method described in any of the preceding claims.

[0016] Fifthly, embodiments of this application provide a computer program product that, when run on a terminal device, causes the electronic device to execute any of the methods described above.

[0017] The beneficial effects of the embodiments in this application compared with the prior art are: This application provides a method for parallel connection of battery clusters. When a battery cluster needs to be connected to the bus of an energy storage system, the method acquires the first bus voltage, the first bus current, and the voltage of the target battery cluster to be connected to the bus of the energy storage system. If the difference between the first bus voltage and the target battery cluster is less than or equal to a first difference threshold, and the first bus current is less than or equal to a preset current threshold, the method controls the target battery cluster to be connected to the bus of the energy storage system. By acquiring the first bus voltage of the energy storage system and the voltage of the target battery cluster, and determining whether the difference between them is less than or equal to the first difference threshold, parallel connection is only allowed when the voltages are similar. This avoids excessive inrush current caused by large voltage differences during parallel connection, preventing electrical damage to the battery cluster and other equipment in the energy storage system, extending equipment lifespan, reducing the probability of failure, and ensuring the safe and stable operation of the entire energy storage system. While meeting the voltage matching conditions, the first bus current is also required to be less than or equal to the preset current threshold. This further limits the current level during parallel connection, preventing the battery cluster from being connected when the bus current is already large. This avoids safety issues such as overheating and short circuits caused by the current superposition exceeding the system's carrying capacity, thus enhancing the safety of parallel operation. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic diagram illustrating the implementation process of a parallel battery cluster method provided for the implementation of this application; Figure 2 A schematic diagram of a circuit structure provided in an embodiment of this application; Figure 3 This is a schematic diagram of the structure of a parallel battery cluster device provided in an embodiment of this application; Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0020] 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 this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0021] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0022] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0023] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrases "if determined" or "if detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once detected," or "in response to detection."

[0024] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] References to "one embodiment" or "some embodiments" in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized.

[0026] Based on the problems in related technologies, this application provides a method for parallel connection of battery clusters that can be applied to electronic devices. Electronic devices may include: mobile phones, tablets, wearable devices, augmented reality (AR) / virtual reality (VR) devices, laptops, ultra-mobile personal computers (UMPCs), netbooks, personal digital assistants (PDAs), PCS, battery management systems (BMS), etc. This application does not impose any restrictions on the specific type of electronic device. Figure 1 A schematic diagram illustrating the implementation process of a parallel battery cluster method provided for the purposes of this application is shown below. Figure 1 As shown, the parallel connection method for battery clusters includes: Step S101: When it is necessary to connect the battery cluster to the bus of the energy storage system, obtain the first bus voltage, the first bus current and the voltage of the target battery cluster to be connected to the bus of the energy storage system.

[0027] In this embodiment, a battery cluster is a collection of batteries composed of multiple individual cells connected in series, parallel, or series-parallel. It is the basic unit for storing and releasing electrical energy in an energy storage system, providing a certain voltage and current output to meet the energy demands of the system under different operating conditions. For example, in a large-scale energy storage power station, multiple battery clusters are connected in parallel to provide peak shaving and frequency regulation services to the power grid. An energy storage system is a system capable of storing electrical energy and releasing it when needed. It typically consists of battery clusters, a battery management system (BMS), and a power conversion system (PCS). In an energy storage system, a bus is a conductor used to collect and distribute electrical energy; it can be a DC bus or an AC bus, depending on the type and design of the energy storage system. The bus connects the battery clusters, power conversion system, and other components to achieve the transmission and exchange of electrical energy. The first bus voltage refers to the current voltage value of the energy storage system bus. This voltage value reflects the potential level on the bus and is one of the important parameters for determining whether a battery cluster can be connected to the bus. The first bus current is the current flowing through the energy storage system bus at the current moment. The magnitude and direction of the bus current reflect the flow of electrical energy on the bus. When connecting battery clusters in parallel, the magnitude of the bus current needs to be considered to avoid excessive current due to parallel operation, which could damage the system equipment. The voltage of the target battery cluster is the voltage value of the battery cluster to be connected to the energy storage system bus. This voltage value needs to be matched with the bus voltage. Only when the voltage difference between the two is within a certain range can the parallel connection process be guaranteed to proceed smoothly and the generation of inrush current be reduced.

[0028] In this embodiment, the voltage of the first bus can be measured in real time by installing a voltage sensor on the bus of the energy storage system. The voltage sensor converts the voltage signal of the bus into an electrical signal, which is then transmitted to the electronic equipment. Similarly, a voltage sensor can be installed at the output end of the target battery cluster to obtain its voltage value. A current sensor, such as a Hall current sensor, can be installed on the bus to measure the current of the first bus. The current sensor converts the current signal on the bus into a measurable electrical signal and transmits it to the electronic equipment.

[0029] Step S102: When the difference between the first bus voltage and the voltage is less than or equal to a first difference threshold and the first bus current is less than or equal to a preset current threshold, control the target battery cluster to be connected to the bus of the energy storage system.

[0030] In this embodiment, the first difference threshold is a pre-set upper limit for voltage difference. When the difference between the first bus voltage and the target battery cluster voltage is less than or equal to this threshold, the two voltages are considered close, satisfying the voltage conditions for parallel connection. The setting of this threshold needs to be reasonably selected based on the characteristics of the battery cluster and the energy storage system, typically taking into account factors such as the battery's charge / discharge characteristics and internal resistance. The preset current threshold is a pre-set upper limit for bus current. When connecting battery clusters in parallel, the first bus current is required to be less than or equal to this threshold to ensure that the parallel operation does not lead to excessive bus current, avoiding damage such as overload or overheating to the system equipment. The setting of the preset current threshold should comprehensively consider factors such as the energy storage system's capacity and the equipment's rated current.

[0031] In this embodiment, the obtained first bus voltage and the target battery cluster voltage can be subtracted to obtain the voltage difference. The calculated voltage difference is compared with a first difference threshold, and the first bus current is compared with a preset current threshold. The parallel connection condition is met only when the voltage difference is less than or equal to the first difference threshold and the first bus current is less than or equal to the preset current threshold. When the parallel connection condition is met, the controller generates a corresponding control signal. This control signal can be a digital signal or an analog signal, depending on the control method of the parallel switch. The control signal is transmitted to the parallel switch, such as a contactor or circuit breaker. After receiving the control signal, the parallel switch closes the switch, connecting the target battery cluster to the bus of the energy storage system, thus realizing the parallel operation.

[0032] The method provided in this application precisely controls the difference between the first bus voltage and the target battery cluster voltage to be within a first difference threshold, thus avoiding excessive inrush current generated during parallel connection due to excessive voltage difference. Excessive inrush current may damage individual battery cells, connecting lines, and other electrical equipment in the energy storage system, such as power conversion systems. This method effectively reduces this risk, ensuring the safety of equipment and personnel. It also requires the first bus current to be less than or equal to a preset current threshold to prevent the battery cluster from being connected when the bus current is already high, which could lead to a further increase in bus current, exceeding the rated load capacity of the system equipment, causing overload, overheating, or even fires and other safety accidents. This further enhances the safety of parallel operation. By explicitly setting thresholds for voltage difference and bus current as parallel connection conditions, parallel operation only occurs when these conditions are simultaneously met. This precise condition control method reduces failures caused by blind parallel connection, improves the success rate of parallel operation, ensures that the target battery cluster can be reliably connected to the energy storage system bus, and guarantees the normal operation of the energy storage system. Because voltage and current are strictly controlled during parallel connection, the paralleled battery clusters and energy storage system can work together better, reducing problems such as system voltage fluctuations and current instability caused by improper parallel connection. This helps maintain the stable operation of the energy storage system, improves system reliability and availability, and reduces power outage time and economic losses caused by system failures.

[0033] In some embodiments, prior to step S101, the method further includes: Step S1: Obtain the charging and discharging status information of the energy storage system.

[0034] In this embodiment, the charging / discharging status information describes whether the energy storage system is currently in a charging or discharging state. A charging state means the energy storage system absorbs and stores electrical energy from an external power source (such as the power grid, renewable energy generation equipment, etc.); a discharging state means the energy storage system releases the stored electrical energy to supply the load or feed it back to the power grid.

[0035] In this embodiment, the charging and discharging status of the energy storage system can be monitored in real time by installing current sensors, voltage sensors, and related power measurement devices. For example, the current sensor can measure the direction and magnitude of the current flowing into or out of the energy storage system. When current flows into the energy storage system, it can be preliminarily determined that it is in a charging state; when current flows out of the energy storage system, it can be preliminarily determined that it is in a discharging state. The current, voltage, and other data collected by the sensors are transmitted to an electronic device. The electronic device comprehensively analyzes these data according to a preset algorithm and logic to accurately determine whether the energy storage system is currently in a charging or discharging state, and generates corresponding charging and discharging status information.

[0036] Step S2: When the charging / discharging condition information is in the discharging condition, the battery clusters with voltages lower than the first bus voltage are identified as the target battery clusters to be connected to the bus of the energy storage system, and the connection order is determined based on the voltage of the target battery clusters from high to low.

[0037] In this embodiment, the target battery clusters are specifically defined based on the different charging and discharging conditions of the energy storage system. Under discharging conditions, the target battery clusters are those with a voltage lower than the first bus voltage; under charging conditions, the target battery clusters are those with a voltage higher than the first bus voltage. These target battery clusters are the objects to be subsequently connected to the energy storage system bus in a certain order. The connection order refers to the sequence in which multiple target battery clusters are connected to the energy storage system bus, provided that the parallel connection conditions are met. The connection order is determined according to different voltage sorting rules under different charging and discharging conditions. The purpose is to make the parallel connection process smoother, reduce the impact on the system, and improve the system's stability and efficiency.

[0038] In this embodiment, after obtaining the first bus voltage of the energy storage system, all battery clusters to be connected in parallel are traversed, and the voltage of each battery cluster is measured. The voltage of each battery cluster is compared with the first bus voltage, and battery clusters with voltages lower than the first bus voltage are selected. These battery clusters are the target battery clusters under discharge conditions. The selected target battery clusters can be sorted in descending order of voltage. Common sorting algorithms, such as bubble sort and quicksort, can be used to implement the voltage sorting function in the electronic device. After sorting, the target battery cluster with the highest voltage will be the first to be connected to the bus of the energy storage system, and so on, with the battery cluster with the second highest voltage being the second to be connected, thus determining the connection order of all target battery clusters.

[0039] Step S3: When the charging / discharging condition information is a charging condition, the battery clusters with voltages greater than the first bus voltage are identified as target battery clusters to be connected to the bus of the energy storage system, and the connection order is determined based on the voltage of the target battery clusters from low to high.

[0040] In this embodiment, battery clusters with voltages greater than the first bus voltage can be selected as target battery clusters under charging conditions. The target battery clusters under charging conditions are then sorted in ascending order of voltage. A suitable sorting algorithm can also be used to perform this sorting operation in the electronic device. After sorting, the target battery cluster with the lowest voltage is the first to be connected to the energy storage system bus, followed by the battery cluster with the second lowest voltage, and so on, determining the connection order of all target battery clusters.

[0041] The method provided in this application, under discharge conditions, connects the target battery cluster in descending voltage order. This avoids large circulating currents caused by excessive voltage differences during parallel connection, reducing the impact on the battery cluster and bus, thereby protecting the battery and power equipment and improving the stability of the energy storage system. Under charging conditions, connecting the target battery cluster in ascending voltage order also reduces the impact of circulating currents, making the charging process smoother, reducing system fluctuations caused by voltage mismatch, and ensuring reliable operation of the energy storage system. A reasonable connection sequence can reduce overcharging and over-discharging of the battery cluster during charging and discharging, preventing accelerated aging of the battery due to prolonged exposure to unreasonable charging and discharging conditions. By balancing the charging and discharging process of the battery cluster, the overall lifespan of the battery is extended, and the operation and maintenance costs of the energy storage system are reduced.

[0042] In some embodiments, after step S101, the method further includes: Step S103: If the charging / discharging condition information is a discharging condition and the difference between the first bus voltage and the voltage is greater than the second difference threshold, continue to obtain the second bus voltage of the bus.

[0043] In this embodiment, the second bus voltage is the bus voltage value obtained again when the difference between the first bus voltage and the target battery cluster voltage exceeds a second difference threshold. By obtaining the second bus voltage, it can be further determined whether voltage adjustment is required. The second difference threshold is a preset upper limit value for voltage difference, used to determine whether the difference between the first bus voltage and the target battery cluster voltage is too large. When the difference exceeds this threshold, it indicates a large voltage difference, requiring further operation to adjust the voltage.

[0044] In this embodiment, under discharge conditions, the electronic equipment of the energy storage system acquires the first bus voltage and the voltage of the target battery cluster in real time and calculates the difference between them. This difference is compared with a pre-set second difference threshold. If the difference between the first bus voltage and the target battery cluster voltage is greater than the second difference threshold, it indicates a large voltage difference. Since the energy storage system is in discharge condition, the system continues to discharge, and the electronic equipment continues to acquire the second bus voltage for subsequent judgment and adjustment.

[0045] Step S104: When the difference between the second bus voltage and the voltage is greater than the first difference threshold and less than or equal to the second difference threshold, voltage loop adjustment is performed on the energy storage system so that the difference between the adjusted third bus voltage and the voltage is less than or equal to the first difference threshold.

[0046] In this embodiment, voltage loop regulation is a closed-loop control system regulation method. By detecting the deviation between the bus voltage and the target voltage (here, the target voltage is the voltage that makes the voltage difference with the target battery cluster meet the requirements), the regulator (such as a proportional-integral-derivative regulator, PID regulator) outputs a control signal to adjust the power output of the energy storage system, thereby stabilizing the bus voltage near the target value.

[0047] In this embodiment, the electronic device can calculate the difference between the second bus voltage and the target battery cluster voltage, and compare this difference with a first difference threshold and a second difference threshold. If the difference between the second bus voltage and the target battery cluster voltage is greater than the first difference threshold and less than or equal to the second difference threshold, it indicates that the voltage difference is within the adjustable range, and the electronic device activates the voltage loop regulation function. By adjusting the power output of the energy storage system, a regulator (such as a PID regulator) outputs a control signal based on the voltage deviation to gradually adjust the bus voltage until the difference between the adjusted third bus voltage and the target battery cluster voltage is less than or equal to the first difference threshold.

[0048] Step S105: When the difference between the adjusted third bus voltage and the voltage is less than or equal to the first difference threshold, control the energy storage system to perform constant voltage discharge and obtain the second bus current of the bus.

[0049] In this embodiment, the third bus voltage is the voltage value reached by the bus after voltage loop regulation. The difference between this voltage value and the target battery cluster voltage should be less than or equal to the first difference threshold to meet the conditions for the battery cluster to be connected to the bus. Constant voltage discharge is a discharge method in which the energy storage system maintains a basically constant bus voltage during the discharge process. By controlling the output power of the energy storage system, the bus voltage is stabilized at a set value, providing a stable voltage supply to the load. The second bus current is the bus current value obtained during the constant voltage discharge process of the energy storage system. This current value reflects the load condition of the bus and is one of the important bases for determining whether the target battery cluster can be connected.

[0050] In this embodiment, when the difference between the adjusted third bus voltage and the target battery cluster voltage is less than or equal to a first difference threshold, the electronic device controls the energy storage system to enter a constant voltage discharge mode. By monitoring the bus voltage in real time, the output power of the energy storage system is adjusted according to the voltage deviation to keep the bus voltage stable at the set value. During the constant voltage discharge process of the energy storage system, the electronic device acquires the second bus current in real time to understand the load condition of the bus.

[0051] Step S106: When the second bus current is less than or equal to the preset current threshold, control the target battery cluster to be connected to the bus, wherein the second difference threshold is greater than the first difference threshold.

[0052] In this embodiment, the electronic device compares the acquired second bus current with a preset current threshold. If the second bus current is less than or equal to the preset current threshold, the electronic device sends a control signal to control the target battery cluster to connect to the bus, thus completing the parallel connection operation of the battery cluster.

[0053] The method provided in this application provides a graded judgment and adjustment of the difference between the bus voltage and the target battery cluster voltage by setting a second difference threshold and a first difference threshold. When the voltage difference is large, the second bus voltage is obtained first, and the energy storage system needs to be discharged to reduce the voltage difference, avoiding unreasonable connection operations directly, reducing the impact and failure caused by voltage mismatch, and improving the safety and stability of the battery cluster connection process. When the difference between the second bus voltage and the target battery cluster is greater than the first difference threshold and less than or equal to the second difference threshold, the bus voltage can be kept stable during voltage loop regulation and constant voltage discharge, providing a stable power supply to the load. At the same time, the connection of the target battery cluster is reasonably controlled according to the bus current, avoiding the greater burden on the system when the battery cluster is connected under heavy load, optimizing the discharge performance of the energy storage system, and improving power quality. A reasonable voltage regulation and battery cluster connection strategy can reduce overcharging, over-discharging, and overcurrent phenomena of batteries and power equipment during charging and discharging, reduce equipment losses and heat generation, thereby extending the service life of batteries and equipment and reducing the operation and maintenance costs of the energy storage system.

[0054] In some embodiments, after step S101, the method further includes: Step S107: When the charging / discharging condition information is a discharging condition and the difference between the first bus voltage and the voltage is greater than the first difference threshold and less than or equal to the second difference threshold, voltage loop adjustment is performed on the energy storage system so that the difference between the adjusted fourth bus voltage and the voltage is less than the first difference threshold.

[0055] In this embodiment, under discharge conditions, the electronic device can acquire the first bus voltage and the voltage of the target battery cluster in real time and calculate the difference between them. This difference is compared with a pre-set first difference threshold and a second difference threshold. If the difference between the first bus voltage and the target battery cluster voltage is greater than the first difference threshold and less than or equal to the second difference threshold, it indicates that the voltage difference is within the adjustable range, and the electronic device activates the voltage loop regulation function. By adjusting the power output of the energy storage system, a regulator (such as a PID regulator) outputs a control signal based on the voltage deviation, gradually adjusting the bus voltage until the difference between the adjusted fourth bus voltage and the target battery cluster voltage is less than or equal to the first difference threshold.

[0056] Step S108: When the difference between the adjusted fourth bus voltage and the voltage is less than or equal to the first difference threshold, control the energy storage system to perform constant voltage discharge and obtain the third bus current of the bus.

[0057] In this embodiment, the third bus current is the current flowing through the bus during the constant voltage discharge process of the energy storage system. This current reflects the load condition of the bus and is an important reference indicator for determining whether it can be connected to the target battery cluster.

[0058] In this embodiment, when the difference between the adjusted fourth bus voltage and the target battery cluster voltage is less than or equal to a first difference threshold, the electronic device controls the energy storage system to enter a constant voltage discharge mode. By monitoring the bus voltage in real time, the output power of the energy storage system is adjusted according to the voltage deviation to keep the bus voltage stable at the set value. During the constant voltage discharge process of the energy storage system, the electronic device acquires the third bus current in real time to understand the load condition of the bus.

[0059] Step S109: When the current of the third bus is less than or equal to the preset current threshold, control the target battery cluster to be connected to the bus, wherein the second difference threshold is greater than the first difference threshold.

[0060] In this embodiment, the electronic device compares the acquired third bus current with a preset current threshold. If the third bus current is less than or equal to the preset current threshold, the electronic device sends a control signal to control the target battery cluster to connect to the bus, thus completing the parallel connection operation of the battery cluster.

[0061] The method provided in this application embodiment classifies and adjusts the difference between the bus voltage and the target battery cluster voltage by setting a first difference threshold and a second difference threshold. Voltage loop adjustment is performed when the voltage difference is within an adjustable range, avoiding potential shocks and malfunctions caused by direct integration of the battery cluster due to voltage mismatch. This improves the safety and stability of the battery cluster integration process and reduces damage to the battery and power equipment. Voltage loop adjustment ensures that the bus voltage reaches a better match with the target battery cluster voltage before integration, while the constant voltage discharge mode guarantees the stability of the bus voltage during discharge, providing high-quality power to the load. Simultaneously, reasonable control of the integration of the target battery cluster based on the bus current avoids placing a greater burden on the system when integrating the battery cluster under heavy load, optimizing the discharge performance of the energy storage system. Reasonable voltage adjustment and battery cluster integration strategies can reduce overcharging, over-discharging, and overcurrent phenomena during the charging and discharging processes of batteries and power equipment, reducing equipment losses and heat generation, thereby extending the service life of batteries and equipment and reducing the operation and maintenance costs of the energy storage system.

[0062] In some embodiments, after step S101, the method further includes: Step S110: If the charging / discharging condition information is a charging condition and the difference between the first bus voltage and the voltage is greater than the third difference threshold, continue to obtain the fifth bus voltage of the bus.

[0063] In this embodiment, the third difference threshold is a pre-set, relatively large voltage difference limit value, used to determine whether the difference between the first bus voltage and the target battery cluster voltage is too large. When the difference is greater than this threshold, it indicates that the voltage difference is large, and subsequent operations cannot be performed directly; it is necessary to wait for the voltage situation to change.

[0064] In this embodiment, the electronic device first determines the current charging / discharging condition. When it is determined to be in a charging condition, it acquires the first bus voltage and the voltage of the target battery cluster in real time and calculates the difference between them. This difference is then compared with a pre-set third difference threshold. If the difference between the first bus voltage and the target battery cluster voltage is greater than the third difference threshold, it indicates a large voltage difference, and subsequent operations cannot be performed immediately. The electronic device then continues to acquire the fifth bus voltage and waits for the voltage situation to change.

[0065] Step S111: If the difference between the fifth bus voltage and the voltage is less than or equal to a third difference threshold and greater than a first difference threshold, voltage loop adjustment is performed on the energy storage system so that the difference between the adjusted sixth bus voltage and the voltage is less than or equal to a first difference threshold.

[0066] In this embodiment, the voltage value reached by the sixth bus after voltage loop adjustment should be less than or equal to the voltage of the target battery cluster, so as to meet the condition of the target battery cluster being connected to the bus.

[0067] In this embodiment, the electronic device calculates the difference between the fifth bus voltage and the target battery cluster voltage, and compares this difference with a third difference threshold and a first difference threshold. If the difference between the fifth bus voltage and the target battery cluster voltage is less than or equal to the third difference threshold and greater than the first difference threshold, it indicates that the voltage difference is within an adjustable range, and the electronic device activates the voltage loop regulation function. By adjusting the charging power of the energy storage system, a regulator (such as a PID regulator) outputs a control signal based on the voltage deviation to gradually adjust the bus voltage until the difference between the adjusted sixth bus voltage and the target battery cluster voltage is less than or equal to the first difference threshold.

[0068] Step S112: When the difference between the adjusted sixth bus voltage and the voltage is less than or equal to the first difference threshold, control the energy storage system to perform constant voltage charging and obtain the fourth bus current of the bus.

[0069] In this embodiment, when the difference between the adjusted fifth bus voltage and the target battery cluster voltage is less than or equal to a first difference threshold, the electronic device controls the energy storage system to enter a constant voltage charging mode. By monitoring the bus voltage in real time, the charging power of the energy storage system is adjusted according to the voltage deviation to keep the bus voltage stable at the set value. During the constant voltage charging process of the energy storage system, the electronic device acquires the fourth bus current in real time to understand the charging load of the bus.

[0070] Step S113: When the current of the fourth bus is less than or equal to the preset current threshold, control the target battery cluster to be connected to the bus, wherein the third difference threshold is greater than the first difference threshold.

[0071] In this embodiment, the electronic device compares the acquired fourth bus current with a preset current threshold. If the fourth bus current is less than or equal to the preset current threshold, it indicates that the bus charging load is light. At this time, the electronic device sends a control signal to control the target battery cluster to be connected to the bus, thus completing the parallel connection operation of the battery cluster.

[0072] The method provided in this application provides a tiered judgment and adjustment of the difference between the bus voltage and the target battery cluster voltage by setting a third difference threshold and a first difference threshold. When the voltage difference is large, it waits for an appropriate time; when the voltage difference is within an adjustable range, it performs voltage loop adjustment. This avoids potential shocks and malfunctions that might result from directly integrating the battery cluster due to voltage mismatch, improving the safety and stability of the battery cluster integration process and reducing damage to the batteries and power equipment.

[0073] In some embodiments, after step S101, the method further includes: Step S114: When the charging / discharging condition information is a charging condition and the difference between the first bus voltage and the voltage is greater than a first difference threshold and less than or equal to a third difference threshold, voltage loop adjustment is performed on the energy storage system so that the difference between the adjusted seventh bus voltage and the voltage is less than or equal to the first difference threshold.

[0074] In this embodiment, when the charging condition is determined, the voltage of the first bus and the voltage of the target battery cluster are acquired in real time, and the difference between them is calculated. This difference is compared with a preset first difference threshold and a third difference threshold. If the difference between the first bus voltage and the target battery cluster voltage is greater than the first difference threshold and less than or equal to the third difference threshold, it indicates that the voltage difference is within an adjustable range, and the electronic device activates the voltage loop regulation function. By adjusting the charging power of the energy storage system, a regulator (such as a PID regulator) outputs a control signal based on the voltage deviation, thereby gradually adjusting the bus voltage.

[0075] Step S115: When the difference between the adjusted seventh bus voltage and the voltage is less than or equal to the first difference threshold, control the energy storage system to perform constant voltage charging and obtain the fifth bus current of the bus.

[0076] In this embodiment, during the voltage loop adjustment process, the electronic device monitors the changes in the bus voltage in real time. When the difference between the adjusted seventh bus voltage and the target battery cluster voltage is less than or equal to a first difference threshold, it indicates that the voltage adjustment has achieved the expected effect. At this time, the electronic device controls the energy storage system to enter a constant voltage charging mode. By monitoring the bus voltage in real time and adjusting the charging power of the energy storage system according to the voltage deviation, the bus voltage is kept stable at the set value, providing a stable voltage environment for the subsequent integration of battery clusters.

[0077] Step S116: If the current of the fifth bus is less than or equal to the preset current threshold, control the target battery cluster to be connected to the bus, wherein the third difference threshold is greater than the first difference threshold.

[0078] In this embodiment, the acquired fifth bus current is compared with a preset current threshold. If the fifth bus current is less than or equal to the preset current threshold, it indicates that the bus charging load is light. At this time, the electronic device sends a control signal to control the target battery cluster to be connected to the bus, thus completing the parallel connection operation of the battery cluster.

[0079] The method provided in this application, by setting a first difference threshold and a third difference threshold, classifies and adjusts the difference between the bus voltage and the target battery cluster voltage. Voltage loop adjustment is performed when the voltage difference is within an adjustable range, avoiding potential shocks and malfunctions caused by directly integrating the battery cluster due to voltage mismatch. This improves the safety and stability of the battery cluster integration process and reduces damage to the battery and power equipment. Voltage loop adjustment ensures that the bus voltage reaches a good match with the target battery cluster voltage before integration, while the constant voltage charging mode guarantees the stability of the bus voltage during charging, providing high-quality charging energy to the battery. Simultaneously, by rationally controlling the integration of the target battery cluster based on the bus current, it avoids placing a greater burden on the system when integrating the battery cluster under heavy charging load, thus optimizing the charging performance and overall operating performance of the energy storage system.

[0080] In some embodiments, Figure 2 A schematic diagram of a circuit structure provided in an embodiment of this application, such as... Figure 2 As shown, each target battery cluster 100 is connected to the bus 200 via a pre-charging circuit 300. The battery cluster 100 is also connected to the bus 200 via a main contactor circuit 400. The pre-charging circuit 300 is connected in parallel with the main contactor circuit 400. The pre-charging circuit 300 includes a pre-charging contactor and a pre-charging resistor. The main contactor circuit 400 includes a main contactor.

[0081] In this embodiment, the pre-charging circuit 300 pre-charges the target battery cluster before it is connected to the bus. Its function is to limit the initial charging current, preventing excessive current from impacting the battery cluster and other equipment on the bus, thus protecting the equipment and extending its service life. The main contactor circuit 400 includes the circuitry of a main contactor, a high-capacity switching device used to control the on / off state of a circuit. After the target battery cluster completes pre-charging, closing the main contactor formally connects the target battery cluster to the bus, enabling it to participate normally in the charging and discharging process of the energy storage system. The pre-charging contactor is a key switching element in the charging circuit, used to control the on / off state of the pre-charging circuit. When pre-charging of the target battery cluster is required, the pre-charging contactor is closed, allowing current to flow into the target battery cluster through the pre-charging resistor; after pre-charging is complete, the pre-charging contactor is opened, disconnecting the pre-charging circuit. The pre-charging resistor is a resistive element connected in series in the pre-charging circuit, its main function being to limit the pre-charging current. When the target battery cluster is initially connected to the bus, the voltage difference between it and the bus will cause a large inrush current. The pre-charge resistor can effectively limit this current, protecting the battery cluster and other equipment on the bus. The main contactor is the core component of the main contactor circuit and is a high-capacity electromagnetic switching device. It can quickly and reliably connect or disconnect the main circuit under the action of control signals, realizing the formal connection or disconnection of the target battery cluster and the bus. It is an important electrical control element in the energy storage system.

[0082] In some embodiments, the busbar controlling the connection of the target battery cluster to the energy storage system includes: Step S201: Control the pre-charge contactor to close.

[0083] In this embodiment, the electronic device sends a control signal to close the pre-charge contactor in the pre-charge circuit 300. At this time, the pre-charge circuit is activated, and current begins to pre-charge the target battery cluster through the pre-charge resistor. The pre-charge resistor limits the magnitude of the initial charging current, preventing damage to the battery cluster and bus equipment due to excessive current.

[0084] Step S202: Obtain the voltage difference across the pre-charging circuit.

[0085] In this embodiment of the application, during the pre-charging process, the electronic device monitors the voltage across the pre-charging circuit in real time using a voltage sensor. The voltage sensor converts the collected voltage signal into an electrical signal and transmits it to the electronic device for analysis and processing, thereby obtaining the voltage difference across the pre-charging circuit.

[0086] In step S203, if the voltage difference across the pre-charge circuit is less than or equal to the fourth difference threshold, control the main contactor to close and control the pre-charge contactor to open.

[0087] In this embodiment, the electronic device compares the voltage difference across the pre-charge resistor with a fourth difference threshold. When the voltage difference is less than or equal to the fourth difference threshold, it indicates that the voltage of the target battery cluster is close to the bus voltage. At this time, the electronic device sends a control signal to close the main contactor, formally connecting the target battery cluster to the bus. Simultaneously, the electronic device sends another control signal to open the pre-charge contactor, cutting off the pre-charge circuit and completing the connection operation of the target battery cluster. The fourth difference threshold can be considered a relatively small value.

[0088] The method provided in this application effectively limits the inrush current when the target battery cluster is initially connected to the bus via the pre-charging circuit and pre-charging resistor. Excessive inrush current can damage individual cells in the battery cluster, affecting battery performance and lifespan, and can also impact other electrical equipment on the bus, accelerating equipment aging and damage. Through the pre-charging process, the voltage of the target battery cluster gradually rises to near the bus voltage before the main contactor is closed, avoiding the generation of inrush current, thus protecting the battery cluster and bus equipment and extending equipment lifespan. Pre-charging before the target battery cluster is connected to the bus ensures voltage matching between the battery cluster and the bus, reducing electrical faults and safety hazards caused by voltage mismatch. Closing the main contactor only when the voltage difference is less than or equal to the fourth difference threshold avoids dangerous situations such as arcing and short circuits caused by excessive voltage differences, improving the safety and reliability of the energy storage system.

[0089] In some embodiments, the method further includes: Step S117: Determine the state of charge (SOC) value of each battery cluster connected to the energy storage system.

[0090] In this embodiment, the State of Charge (SOC) describes the ratio of the battery's current remaining capacity to its capacity when fully charged, typically expressed as a percentage. For example, an SOC of 50% indicates that the battery currently has half its full capacity. The State of Charge is a crucial indicator of a battery's state of charge, directly impacting its charge / discharge performance and lifespan.

[0091] In this embodiment, the electronic device uses a battery management system (BMS) to collect parameters such as voltage, current, and temperature of individual cells in each battery cluster in real time. Using these parameters, combined with the battery's charge / discharge model and algorithms, the state of charge (SOC) value of each battery cluster is calculated. For example, using the ampere-hour integration method, the remaining charge of the battery is calculated by integrating the battery's charge / discharge current and combining it with the battery's initial charge and capacity information, thus obtaining the SOC value.

[0092] Step S118: Determine the average state of charge value based on the state of charge value of each battery cluster.

[0093] In this embodiment, the average state of charge (SOC) value is the average calculated from the SOC values ​​of each battery cluster connected to the energy storage system. It reflects the overall charge level of the batteries in the entire energy storage system, providing a reference for subsequent charge and discharge control based on the battery SOC status.

[0094] In this embodiment of the application, the electronic device sums the calculated state of charge values ​​of each battery cluster and then divides them by the number of battery clusters to obtain the average state of charge value.

[0095] Step S119: When the energy storage system is in a discharge state and the state of charge (SOC) value of a battery cluster is less than the first SOC threshold, the energy storage system is controlled to enter constant voltage discharge. The first SOC threshold is determined based on the average SOC value and a preset first SOC deviation threshold.

[0096] In this embodiment, the first state of charge threshold is a pre-set state of charge limit value used to determine whether the battery cluster's charge level is too low under discharge conditions. When the battery cluster's state of charge value is less than this threshold, it indicates that the battery charge is already low, and continued discharge may damage the battery, requiring corresponding control measures. The first state of charge threshold is determined based on the average state of charge value and a preset first state of charge deviation threshold. Specifically, the first state of charge threshold is obtained by subtracting the first state of charge deviation threshold from the average state of charge value. The first state of charge deviation threshold is a pre-set limit value used to measure the degree of deviation between the battery cluster's state of charge value and the average state of charge value.

[0097] In this embodiment, the electronic device monitors the charging and discharging status information of the energy storage system in real time. When a discharging condition is determined, the state of charge (SOC) value of each battery cluster is checked. It is determined whether any battery cluster has an SOC value lower than a first SOC threshold. If the condition is met, it indicates that a battery cluster has low charge, and the electronic device sends a control signal to cause the energy storage system to enter a constant-voltage discharge mode. By adjusting the discharge power of the energy storage system, the bus voltage is kept stable, preventing excessive voltage drop due to low battery cluster charge, which could affect the normal operation of the load.

[0098] Step S120: When the charging and discharging condition information of the energy storage system is a charging condition and the state of charge value of the battery cluster is greater than the second state of charge threshold, reduce the charging current of the energy storage system or control the energy storage system to enter the constant voltage charging stage, wherein the second state of charge threshold is determined based on the average state of charge value and the preset second state of charge deviation threshold.

[0099] In this embodiment, the second state-of-charge (SOC) threshold is a pre-set SOC limit value used to determine whether the battery cluster's charge is too high during charging. When the SOC value of the battery cluster exceeds this threshold, it indicates that the battery is nearly fully charged. Continuing high-current charging may lead to overcharging, affecting battery performance and lifespan, requiring adjustment of the charging strategy. The constant-voltage charging stage is a charging mode that maintains a relatively constant bus voltage of the energy storage system during charging. By controlling the charging power of the energy storage system and adjusting it in real time based on feedback information from the bus voltage, the bus voltage is stabilized near the set value, providing a stable charging voltage for the battery and avoiding problems such as overcharging and uneven charging. In this embodiment, the second SOC threshold can be equal to the average SOC value plus a pre-set second SOC deviation threshold.

[0100] In this embodiment, when the electronic device determines that the energy storage system is in charging mode, it checks the state of charge (SOC) value of each battery cluster. It determines whether any battery cluster has an SOC value greater than a second SOC threshold. If so, it indicates that some battery clusters have excessive charge. The electronic device can then adopt one of two control strategies: first, reduce the charging current of the energy storage system by adjusting the output power of the charging equipment to reduce the amount of charge entering the battery and prevent overcharging; second, control the energy storage system to enter a constant voltage charging stage to maintain a stable bus voltage, allowing the battery to charge at a stable voltage and avoiding overcharging and uneven charging.

[0101] The method provided in this application, under discharge conditions, promptly controls the energy storage system to enter a constant-voltage discharge mode when the state of charge (SOC) of a battery cluster is too low, thus preventing over-discharge. Over-discharge can lead to damage to the internal battery structure and loss of active materials, severely affecting battery performance and lifespan. Under charging conditions, when the SOC of a battery cluster is too high, the charging current is reduced or a constant-voltage charging stage is entered to prevent overcharging. Overcharging increases internal battery pressure and temperature, causing safety issues such as battery swelling, leakage, and even explosion, while also accelerating battery aging. These control measures effectively protect the battery and extend its lifespan. Under discharge conditions, maintaining a stable bus voltage is crucial for the normal operation of the load. When a battery cluster's charge is too low, potentially causing a drop in bus voltage, entering a constant-voltage discharge mode ensures that the bus voltage fluctuates within a reasonable range, providing stable power to the load and improving system stability. Under charging conditions, proper charging control can prevent system failures caused by uneven battery charging or overcharging, improving system reliability. Controlling charge and discharge based on the state of charge (SOC) of each battery cluster allows for a more balanced SOC across the clusters. During discharge, it prevents some clusters from over-discharging while others remain heavily charged; conversely, it prevents some clusters from overcharging while others are undercharged. This balanced charge and discharge control helps improve the overall energy storage system's efficiency and optimizes system performance.

[0102] Based on various embodiments, the embodiments of the present application provide a method for parallel connection of battery clusters. When a battery cluster needs to be connected in parallel with an operating bus, the master BMS continuously monitors the voltage V_cluster of the cluster to be connected and the bus voltage V_bus. Parallel connection in discharge condition: Find all clusters with cluster voltage less than V_bus, sort them in descending order according to voltage, and confirm the order of clusters to be connected. When V_bus > V_cluster and the difference is greater than the second difference threshold, according to the actual discharge condition of the system, V_bus will slowly approach V_cluster. At this time, the difference between V_bus and V_cluster is less than the second difference threshold and greater than the first difference threshold, and the second difference threshold is greater than the first difference threshold. The PCS controls the voltage loop regulation to stabilize V_bus within a difference less than or equal to the first difference threshold from V_cluster. The system is in constant voltage discharge, and the system discharge current dch_I_bus will slowly decrease. If it is detected that dch_I_bus < I_bus_set1 (according to the pre-charge resistor, system electrical circuit limitation conditions, etc.), start the connection of the cluster to be connected. After meeting the conditions, close the pre-charge contactor of the cluster to be connected, and connect the loop through the pre-charge resistor to limit the current. Detect the voltages on both sides of the pre-charge loop. If the voltage difference is less than ΔV1, then close the main contactor, and then disconnect the pre-charge contactor to complete the safe parallel connection. And so on, gradually connect the clusters to be connected in accordance with the parallel connection order.

[0103] Parallel connection in charge condition: Find all clusters with cluster voltage greater than V_bus, sort them in ascending order according to voltage, and confirm the order of clusters to be connected. When the difference between V_bus < V_cluster is greater than the third difference threshold, according to the actual charge condition of the system, V_bus will slowly approach V_cluster. At this time, the difference between V_bus and V_cluster is less than the third difference threshold and greater than the first difference threshold. The PCS controls the voltage loop regulation to stabilize V_bus within a difference less than ΔV_set from V_cluster. The system is in constant voltage charge, and the system charge current ch_I_bus will slowly decrease. If the BMS detects that ch_I_bus < I_bus_set2, start the connection of the cluster to be connected. After meeting the conditions, close the pre-charge contactor of the cluster to be connected, and connect the loop through the pre-charge resistor to limit the current. Detect the voltages on both sides of the pre-charge loop. If the voltage difference is less than ΔV2, then close the main contactor, and then disconnect the pre-charge contactor to complete the safe parallel connection. And so on, gradually connect the clusters to be connected in accordance with the parallel connection order.

[0104] In some embodiments, during parallel operation, the current I_n of each cluster and the total current I_total can be calculated in real time. The circulating current is then calculated using these two currents: I_circulating = |I_n - I_total / N|. A circulating current alarm threshold I_cir_th can be set. When I_circulating > I_cir_th, a maintenance alarm is issued, indicating a possible abnormal connection impedance. When the circulating current is within the alarm threshold range, a dynamic operating condition strategy can be used to suppress the circulating current. In some embodiments, the system average SOC_avg can be calculated. During discharge: if the SOC of a cluster is less than SOC_avg - ΔSOC_set1, when the voltage of the low-SOC cluster reaches the threshold, constant voltage is initiated, and the constant voltage discharge stage is entered earlier. The discharge current of that cluster decreases, indirectly allowing the high-SOC cluster to undertake more discharge tasks. During charging: if the SOC of a cluster is greater than SOC_avg + ΔSOC_set2, the main control BMS dynamically reduces the total system charging current or enters the constant voltage charging stage earlier, suppressing the charging speed of that cluster and allowing the low-SOC cluster to absorb more energy.

[0105] In this embodiment of the application, the SOC of each cluster is made to converge spontaneously through charge-discharge cycles, thereby reducing the circulating current caused by uneven SOC from the source.

[0106] The method provided in this application, through voltage synchronization and pre-charging processes, completely solves the inrush current problem in parallel connections under arbitrary voltage differences, thus protecting hardware devices. It eliminates the need for expensive hardware such as DC-DC converters, utilizing only existing sensors and actuators, and achieving advanced functions through software algorithm upgrades, resulting in extremely high cost-effectiveness. By employing a SOC-based power bias and circulating current monitoring strategy, circulating current is effectively suppressed, mitigating the "weakest link" effect and improving the system's available capacity and energy efficiency. This method is suitable for upgrading existing energy storage systems and designing new systems, and is easy to implement and promote.

[0107] 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 this application.

[0108] According to the foregoing embodiments, this application provides a parallel battery cluster device. The modules and units included in the device can be implemented by a processor in a computer device; of course, they can also be implemented by specific logic circuits. In the implementation process, the processor can be a central processing unit (CPU), a microprocessor unit (MPU), a digital signal processor (DSP), or a field programmable gate array (FPGA), etc.

[0109] This application provides a parallel connection device for battery clusters. Figure 3 This is a schematic diagram of a parallel battery cluster device provided in an embodiment of this application, as shown below. Figure 3 As shown, the parallel battery cluster device 300 includes: The first acquisition module 301 is used to acquire the first bus voltage, the first bus current, and the voltage of the target battery cluster to be connected to the bus of the energy storage system when it is necessary to connect the battery cluster to the bus of the energy storage system. The first integration module 302 is used to control the target battery cluster to be integrated into the bus of the energy storage system when the difference between the first bus voltage and the voltage is less than or equal to a first difference threshold and the first bus current is less than or equal to a preset current threshold.

[0110] In some embodiments, the battery cluster parallel connection device 300 further includes: The second acquisition module is used to acquire the charging and discharging status information of the energy storage system. The first determining module is used to determine the battery clusters with voltages lower than the first bus voltage as target battery clusters to be connected to the bus of the energy storage system when the charging and discharging condition information is a discharging condition, and to determine the connection order based on the voltage of the target battery clusters from high to low. The second determining module is used to determine, when the charging and discharging condition information is a charging condition, the battery clusters with voltages greater than the first bus voltage as target battery clusters to be connected to the bus of the energy storage system, and determine the connection order based on the voltage of the target battery clusters from low to high.

[0111] In some embodiments, the battery cluster parallel connection device 300 further includes: The third acquisition module is used to continue acquiring the second bus voltage of the bus when the charging and discharging condition information is a discharging condition and the difference between the first bus voltage and the voltage is greater than a second difference threshold. The first control module is used to perform voltage loop regulation on the energy storage system when the difference between the second bus voltage and the voltage is greater than a first difference threshold and less than or equal to the second difference threshold, so that the difference between the adjusted third bus voltage and the voltage is less than or equal to the first difference threshold. The second control module is used to control the energy storage system to perform constant voltage discharge and obtain the second bus current of the bus when the difference between the adjusted third bus voltage and the voltage is less than or equal to a first difference threshold. The second integration module is used to control the target battery cluster to integrate into the bus when the second bus current is less than or equal to the preset current threshold, wherein the second difference threshold is greater than the first difference threshold.

[0112] In some embodiments, the battery cluster parallel connection device 300 further includes: The third control module is used to perform voltage loop adjustment on the energy storage system when the charging and discharging condition information is a discharging condition and the difference between the first bus voltage and the voltage is greater than the first difference threshold and less than or equal to the second difference threshold, so that the difference between the fourth bus voltage of the adjusted bus and the voltage is less than or equal to the first difference threshold. The fourth control module is used to control the energy storage system to perform constant voltage discharge and obtain the third bus current of the bus when the difference between the adjusted fourth bus voltage and the voltage is less than or equal to the first difference threshold. The third integration module is used to control the target battery cluster to integrate into the bus when the third bus current is less than or equal to the preset current threshold, wherein the second difference threshold is greater than the first difference threshold.

[0113] In some embodiments, the battery cluster parallel connection device 300 further includes: The fourth acquisition module is used to continue acquiring the fifth bus voltage of the bus when the charging and discharging condition information is a charging condition and the difference between the first bus voltage and the voltage is greater than the third difference threshold. The fifth control module is used to perform voltage loop regulation on the energy storage system when the difference between the fifth bus voltage and the voltage is less than or equal to a third difference threshold and greater than a first difference threshold, so that the difference between the adjusted sixth bus voltage and the voltage is less than or equal to a first difference threshold. The sixth control module is used to control the energy storage system to perform constant voltage charging and to obtain the fourth bus current of the bus when the difference between the adjusted fifth bus voltage and the voltage is less than or equal to a first difference threshold. The fourth integration module is used to control the target battery cluster to integrate into the bus when the fourth bus current is less than or equal to the preset current threshold, wherein the third difference threshold is greater than the first difference threshold.

[0114] In some embodiments, the battery cluster parallel connection device 300 further includes: The seventh control module is used to perform voltage loop adjustment on the energy storage system when the charging and discharging condition information is charging condition and the difference between the first bus voltage and the voltage is greater than the first difference threshold and less than or equal to the third difference threshold, so that the difference between the seventh bus voltage and the voltage after adjustment is less than or equal to the first difference threshold. The eighth control module is used to control the energy storage system to perform constant voltage charging and to obtain the fifth bus current of the bus when the difference between the adjusted seventh bus voltage and the voltage is less than or equal to the first difference threshold. The fifth integration module is used to control the target battery cluster to integrate into the bus when the current of the fifth bus is less than or equal to the preset current threshold, wherein the third difference threshold is greater than the first difference threshold.

[0115] In some embodiments, the target battery cluster is connected to the bus via a pre-charging circuit, and the target battery cluster is also connected to the bus via a main contactor circuit. The pre-charging circuit is connected in parallel with the main contactor circuit. The pre-charging circuit includes a pre-charging contactor and a pre-charging resistor. The main contactor circuit includes a main contactor. Controlling the connection of the target battery cluster to the bus of the energy storage system includes: controlling the pre-charging contactor to close; acquiring the voltage across the pre-charging circuit; and controlling the main contactor to close and the pre-charging contactor to open when the difference between the voltage across the pre-charging circuit and the bus voltage is less than a fourth difference threshold.

[0116] In some embodiments, the battery cluster parallel connection device 300 further includes: The third determining module is used to determine the state of charge (SOC) value of each battery cluster connected to the energy storage system. The fourth determination module is used to determine the average state of charge value based on the state of charge value of each battery cluster. The ninth control module is used to control the energy storage system to enter constant voltage discharge when the charging and discharging condition information of the energy storage system is in discharge condition and the state of charge value of the battery cluster is less than the first state of charge threshold. The first state of charge threshold is determined based on the average state of charge value and a preset first state of charge deviation threshold. The tenth control module is used to reduce the charging current of the energy storage system or control the energy storage system to enter the constant voltage charging stage when the charging and discharging condition information of the energy storage system is a charging condition and the state of charge value of the battery cluster is greater than the second state of charge threshold. The second state of charge threshold is determined based on the average state of charge value and a preset second state of charge deviation threshold.

[0117] It should be noted that the information interaction and execution process between the above-mentioned devices / units are based on the same concept as the method embodiments of this application. For details on their specific functions and technical effects, please refer to the method embodiments section, and they will not be repeated here.

[0118] In addition, the battery cluster parallel device shown above can be a software unit, a hardware unit, or a combination of software and hardware. It can also be integrated into electronic devices as an independent component, or exist as an independent terminal device.

[0119] 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.

[0120] Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 4 As shown, the electronic device of this embodiment may include: at least one processor 30 ( Figure 4Only one processor 30, memory 31, and computer program 32 stored in memory 31 and executable on at least one processor 30 are shown. When the processor 30 executes the computer program 32, it implements the steps in any of the above method embodiments, or the processor 30 executes the computer program 32 to implement the functions of each module / unit in the above device or system embodiments.

[0121] For example, computer program 32 may be divided into one or more modules / units, one or more of which are stored in memory 31 and executed by processor 30 to complete this application. One or more modules / units may be a series of computer program 32 instruction segments capable of performing a specific function, which describe the execution process of computer program 32 in an electronic device.

[0122] This application also provides a computer-readable storage medium storing a computer program 32, which, when executed by a processor 30, implements the steps described in the above-described method embodiments.

[0123] This application provides a computer program product that, when run on an electronic device, enables the electronic device to perform the steps described in the various method embodiments above.

[0124] If the integrated 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 methods of the above embodiments of this application can be implemented by a computer program 32 instructing related hardware. The computer program 32 can be stored in a computer-readable storage medium, and when executed by the processor 30, it can implement the steps of the various method embodiments described above. The computer program 32 includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. A computer-readable medium can include at least: any entity or device capable of carrying computer program code to a terminal, a recording medium, 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. Examples include USB flash drives, portable hard drives, magnetic disks, or optical disks. In some jurisdictions, according to legislation and patent practice, computer-readable media cannot be electrical carrier signals or telecommunication signals.

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

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

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

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

[0129] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application 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 this application, and should all be included within the protection scope of this application.

Claims

1. A method for parallel connection of battery clusters, characterized in that, include: When it is necessary to connect a battery cluster to the bus of an energy storage system, the first bus voltage, the first bus current, and the voltage of the target battery cluster to be connected to the bus of the energy storage system are obtained. When the difference between the first bus voltage and the voltage is less than or equal to a first difference threshold and the first bus current is less than or equal to a preset current threshold, the target battery cluster is controlled to be connected to the bus of the energy storage system.

2. The method according to claim 1, characterized in that, The method further includes: Obtain the charging and discharging status information of the energy storage system; When the charging and discharging condition information is in the discharging condition, the battery clusters with voltages lower than the first bus voltage are identified as the target battery clusters to be connected to the bus of the energy storage system, and the connection order is determined based on the voltage of the target battery clusters from high to low. When the charging / discharging condition information is in the charging condition, the battery clusters with voltages greater than the first bus voltage are identified as the target battery clusters to be connected to the bus of the energy storage system, and the connection order is determined based on the voltage of the target battery clusters from low to high.

3. The method according to claim 2, characterized in that, The method further includes: If the charging / discharging condition information indicates a discharging condition and the difference between the first bus voltage and the voltage is greater than a second difference threshold, the second bus voltage of the bus will continue to be acquired. When the difference between the second bus voltage and the voltage is greater than a first difference threshold and less than or equal to the second difference threshold, the energy storage system is subjected to voltage loop regulation so that the difference between the adjusted third bus voltage and the voltage is less than or equal to the first difference threshold. When the difference between the adjusted third bus voltage and the voltage is less than or equal to the first difference threshold, the energy storage system is controlled to perform constant voltage discharge and the second bus current of the bus is obtained. When the second bus current is less than or equal to the preset current threshold, the target battery cluster is controlled to be connected to the bus, wherein the second difference threshold is greater than the first difference threshold.

4. The method according to claim 2, characterized in that, The method further includes: When the charging / discharging condition information is a discharging condition, and the difference between the first bus voltage and the voltage is greater than the first difference threshold and less than or equal to the second difference threshold, the energy storage system is subjected to voltage loop regulation so that the difference between the adjusted fourth bus voltage and the voltage is less than or equal to the first difference threshold. If the difference between the adjusted fourth bus voltage and the voltage is less than or equal to the first difference threshold, the energy storage system is controlled to perform constant voltage discharge and the third bus current of the bus is obtained. When the current of the third bus is less than or equal to the preset current threshold, the target battery cluster is controlled to be connected to the bus, wherein the second difference threshold is greater than the first difference threshold.

5. The method according to claim 2, characterized in that, The method further includes: If the charging / discharging condition information indicates a charging condition and the difference between the first bus voltage and the voltage is greater than the third difference threshold, the fifth bus voltage of the bus will continue to be acquired. If the difference between the fifth bus voltage and the voltage is less than or equal to a third difference threshold and greater than a first difference threshold, the energy storage system is subjected to voltage loop regulation so that the difference between the adjusted sixth bus voltage and the voltage is less than or equal to a first difference threshold. If the difference between the adjusted sixth bus voltage and the voltage is less than or equal to the first difference threshold, the energy storage system is controlled to perform constant voltage charging and the fourth bus current of the bus is obtained. When the current of the fourth bus is less than or equal to the preset current threshold, the target battery cluster is controlled to be connected to the bus, wherein the third difference threshold is greater than the first difference threshold.

6. The method according to claim 2, characterized in that, The method further includes: When the charging / discharging condition information is a charging condition and the difference between the first bus voltage and the voltage is greater than a first difference threshold and less than or equal to a third difference threshold, the energy storage system is subjected to voltage loop regulation so that the difference between the adjusted seventh bus voltage and the voltage is less than or equal to the first difference threshold. If the difference between the adjusted seventh bus voltage and the voltage is less than or equal to the first difference threshold, the energy storage system is controlled to perform constant voltage charging, and the fifth bus current of the bus is obtained. When the current of the fifth bus is less than or equal to the preset current threshold, the target battery cluster is controlled to be connected to the bus, wherein the third difference threshold is greater than the first difference threshold.

7. The method according to any one of claims 1 to 6, characterized in that, The target battery cluster is connected to the bus via a pre-charging circuit, and is also connected to the bus via a main contactor circuit. The pre-charging circuit is connected in parallel with the main contactor circuit. The pre-charging circuit includes a pre-charging contactor and a pre-charging resistor. The main contactor circuit includes a main contactor. The bus that controls the connection of the target battery cluster to the energy storage system includes: Control the precharge contactor to close; Obtain the voltage difference across the pre-charging circuit; When the voltage difference across the pre-charge circuit is less than or equal to the fourth difference threshold, the main contactor is controlled to close, and the pre-charge contactor is controlled to open.

8. The method according to any one of claims 1 to 6, characterized in that, The method further includes: Determine the state of charge (SOC) value of each battery cluster connected to the energy storage system; The average state of charge (SOC) value is determined based on the SOC value of each battery cluster. When the energy storage system is in a discharge state and the state of charge (SOC) value of a battery cluster is less than the first SOC threshold, the energy storage system is controlled to enter constant voltage discharge. The first SOC threshold is determined based on the average SOC value and a preset first SOC deviation threshold. When the energy storage system is in a charging state and the state of charge (SOC) value of a battery cluster is greater than the second SOC threshold, the charging current of the energy storage system is reduced or the energy storage system is controlled to enter a constant voltage charging stage. The second SOC threshold is determined based on the average SOC value and a preset second SOC deviation threshold.

9. A battery cluster parallel connection device, characterized in that, include: The first acquisition module is used to acquire the first bus voltage, the first bus current, and the voltage of the target battery cluster to be connected to the bus of the energy storage system when it is necessary to connect the battery cluster to the bus of the energy storage system. The first integration module is used to control the target battery cluster to be integrated into the bus of the energy storage system when the difference between the first bus voltage and the voltage is less than or equal to a first difference threshold and the first bus current is less than or equal to a preset current threshold.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method as described in any one of claims 1 to 8.

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