Control method, control device, processor and storage medium of dual-branch high-power energy storage battery system

Abstract

The present invention relates to the field of new energy technology, and specifically discloses a control method, a control device, a processor and a storage medium for a dual-branch high-power energy storage battery system, wherein the dual-branch high-power energy storage battery system includes a first power supply branch and a second power supply branch, wherein the first power supply branch is connected to a first battery cluster, and the second power supply branch is connected to a second battery cluster, and the method includes: obtaining a first voltage of the first battery cluster and a second voltage of the second battery cluster; determining whether the voltage difference between the first voltage and the second voltage is greater than a first preset threshold; if so, obtaining the current operating condition; performing a discharge balancing operation under a discharge condition; performing a charge balancing operation under a charge condition; performing a standby balancing operation under a standby condition; and connecting the first battery cluster and the second battery cluster. A dual-branch control circuit is used to perform active voltage balancing on battery clusters of different branches, which greatly reduces circulating current and improves safety in use.

Description

Technical Field

[0001] The present invention relates to the field of new energy technology, and in particular to a control method for a dual-branch high-power energy storage battery system, a control device for a dual-branch high-power energy storage battery system, a processor and a computer-readable storage medium. Background Art

[0002] With the leapfrog development of new energy represented by wind power and photovoltaic power generation, the inherent intermittent and volatile nature of new energy has brought a series of problems to the consumption of new energy, peak / frequency regulation of the power grid, and safe and stable operation of the power grid. Taking the frequency regulation of the power system as an example, when the proportion of new energy is small, traditional power sources (thermal power, hydropower) can smooth these fluctuations in real time due to the inherent rotational inertia. However, when large-scale renewable energy sources are connected to the power grid, the power and frequency fluctuations they generate will exceed the regulation capacity of traditional power sources.

[0003] In order to solve the above technical problems, technicians connect battery energy storage systems to the power grid to balance the power grid. In actual applications, based on cost considerations, technicians often use standard energy storage systems or battery packs to connect to the power grid. However, directly connecting to a battery pack or connecting multiple battery packs in parallel has at least the following technical problems:

[0004] First, directly connecting multiple standard battery packs in parallel, because each standard battery pack is equipped with a corresponding main control cabinet, a large amount of space is occupied, which cannot meet the actual needs for application scenarios with limited space resources;

[0005] Secondly, multiple battery packs connected in parallel will have circulating current due to voltage differences, which will reduce the battery life and increase energy consumption, and cannot meet the actual energy storage needs. Summary of the invention

[0006] In order to overcome the above-mentioned technical problems existing in the prior art, the embodiments of the present invention provide a control method, a control device, a processor and a storage medium for a dual-branch high-power energy storage battery system. By adopting a dual-branch control circuit, active voltage balancing is performed on battery clusters in different branches, thereby greatly reducing the circulating current and improving the safety of use.

[0007] In order to achieve the above-mentioned purpose, an embodiment of the present invention provides a control method for a dual-branch high-power energy storage battery system, wherein the dual-branch high-power energy storage battery system includes a first power supply branch and a second power supply branch, wherein the first power supply branch is connected to a first battery cluster, and the second power supply branch is connected to a second battery cluster, and the control method includes: obtaining a first voltage of the first battery cluster and a second voltage of the second battery cluster; determining whether a voltage difference between the first voltage and the second voltage is greater than a first preset threshold; if so, obtaining a current operating condition; when the current operating condition is a discharging condition, performing a discharging balancing operation; when the current operating condition is a charging condition, performing a charging balancing operation; when the current operating condition is a standby condition, performing a standby balancing operation; and connecting the first battery cluster and the second battery cluster.

[0008] Preferably, the control method further comprises: obtaining a preset safety loop current and determining an internal resistance value of each battery cluster; determining a maximum voltage difference between clusters based on the preset safety loop current and the internal resistance value of each battery cluster; and determining the maximum voltage difference as the first preset threshold.

[0009] Preferably, the determining of the internal resistance value of each battery cluster includes: determining the ambient temperature and a preset collection interval; determining a plurality of internal resistance collection capacity points based on the preset collection interval; calibrating the unit discharge current of each battery cell to obtain a calibrated discharge current; performing an internal resistance detection operation at each internal resistance collection capacity point based on the calibrated discharge current to obtain an internal resistance value corresponding to each internal resistance collection capacity point; determining the average internal resistance of each battery cell based on the internal resistance values ​​corresponding to all internal resistance collection capacity points; and determining the internal resistance of the battery cluster based on the ambient temperature and the average internal resistance.

[0010] Preferably, the performing of the internal resistance detection operation includes: performing a full discharge operation on the current battery cell based on the calibrated discharge current; placing the battery cell for a first time to obtain a fully discharged battery cell, and obtaining a first internal resistance of the fully discharged battery cell, the first time being determined based on the discharge temperature rise data and the physical stability data of the current battery cell; performing a full charge operation on the fully discharged battery cell based on the calibrated discharge current; placing the battery cell for a second time to obtain a fully charged battery cell, and obtaining a second internal resistance of the fully charged battery cell, the second time being determined based on the charging temperature rise data and the physical stability data of the current battery cell; determining an upper limit value and a lower limit value of the maximum discharge current, based on the predicted Assume that the detection time is to perform a discharge operation on the fully charged battery cell according to the upper limit value; place a third time to obtain the battery cell after controlled discharge, and obtain the third internal resistance of the battery cell after controlled discharge, and the third time is determined based on the preset detection time, the discharge temperature rise data and the physical stability data; perform a charging operation on the battery cell after controlled discharge according to the lower limit value based on the preset detection time; place the third time to obtain the battery cell after controlled charge, and obtain the fourth internal resistance of the battery cell after controlled charge; determine the internal resistance value of the current battery cell at the current internal resistance acquisition capacity point based on the first internal resistance, the second internal resistance, the third internal resistance and the fourth internal resistance.

[0011] Preferably, the first power supply branch includes a first conduction circuit and a first current reduction circuit arranged in parallel with each other, and the second power supply branch includes a second conduction circuit and a second current reduction circuit arranged in parallel with each other, and the performing of the discharge balancing operation includes: determining a high-voltage battery cluster with a higher voltage and a low-voltage battery cluster with a lower voltage based on the first voltage and the second voltage; connecting the conduction circuit corresponding to the high-voltage battery cluster until the voltage difference between the high-voltage battery cluster and the low-voltage battery cluster is less than or equal to the first preset threshold value; and the performing of the charge balancing operation includes: connecting the conduction circuit corresponding to the low-voltage battery cluster until the voltage difference between the low-voltage battery cluster and the high-voltage battery cluster is less than or equal to the first preset threshold value.

[0012] Preferably, the execution of the standby balancing operation includes: controlling the current reduction circuit corresponding to the low-voltage battery cluster to be turned on, and controlling the conduction circuit corresponding to the high-voltage battery cluster to be turned on; real-time monitoring whether the voltage difference between the low-voltage battery cluster and the high-voltage battery cluster is less than a second preset threshold; if so, determining that the standby balancing operation is completed, and the second preset threshold is less than the first preset threshold.

[0013] Preferably, the first current drop circuit includes a first current drop resistor, the second current drop circuit includes a second current drop resistor, and the control method further includes: determining the resistance value of the first current drop resistor based on the preset safety loop current, the internal resistance of the first battery cluster and the rated voltage, and configuring the first current drop resistor in the first current drop circuit; determining the resistance value of the second current drop resistor based on the preset safety loop current, the internal resistance of the second battery cluster and the rated voltage, and configuring the second current drop resistor in the second current drop circuit.

[0014] Accordingly, an embodiment of the present invention provides a control device for a dual-branch high-power energy storage battery system, wherein the dual-branch high-power energy storage battery system includes a first power supply branch and a second power supply branch, wherein the first power supply branch is connected to a first battery cluster, and the second power supply branch is connected to a second battery cluster, and the control device includes: a voltage acquisition unit, used to acquire a first voltage of the first battery cluster and a second voltage of the second battery cluster; a judgment unit, used to judge whether a voltage difference between the first voltage and the second voltage is greater than a first preset threshold; an operating condition acquisition unit, used to acquire a current operating condition when the voltage difference is greater than the first preset threshold; a first balancing unit, used to perform a discharge balancing operation when the current operating condition is a discharge condition; a second balancing unit, used to perform a charge balancing operation when the current operating condition is a charge condition; a third balancing unit, used to perform a standby balancing operation when the current operating condition is a standby condition; and a connection control unit, used to connect the first battery cluster and the second battery cluster.

[0015] On the other hand, an embodiment of the present invention further provides a processor for running a program, wherein the program, when being run, is used to execute the control method described in the embodiment of the present invention.

[0016] On the other hand, an embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, which implements the method provided by the present invention when the program is executed by a processor.

[0017] Through the technical solution provided by the present invention, the present invention has at least the following technical effects:

[0018] By improving the existing energy storage battery system, adopting a dual-branch energy storage battery system, and using active balancing control to control the charging and discharging of each battery cluster, the technical problem of excessive circulation current can be effectively solved, the battery life can be protected, and the safety of use can be improved.

[0019] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings:

[0021] Figure 1 This is a specific implementation flow chart of the control method of the dual-branch high-power energy storage battery system provided by an embodiment of the present invention;

[0022] Figure 2 It is a structural schematic diagram of a dual-branch high-power energy storage battery system provided by an embodiment of the present invention;

[0023] Figure 3 It is a structural schematic diagram of a control device for a dual-branch high-power energy storage battery system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0025] The terms "system" and "network" in the embodiments of the present invention can be used interchangeably. "Multiple" means two or more than two. In view of this, "multiple" can also be understood as "at least two" in the embodiments of the present invention. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / ", unless otherwise specified, generally indicates that the previous and subsequent associated objects are in an "or" relationship. In addition, it should be understood that in the description of the embodiments of the present invention, the words "first", "second", etc. are only used to distinguish the purpose of description, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order.

[0026] See also Figure 1 The embodiment of the present invention provides a control method for a dual-branch high-power energy storage battery system, wherein the dual-branch high-power energy storage battery system comprises a first power supply branch and a second power supply branch, wherein the first power supply branch is connected to a first battery cluster, and the second power supply branch is connected to a second battery cluster, and the control method comprises:

[0027] S10: acquiring a first voltage of the first battery cluster and a second voltage of the second battery cluster;

[0028] S20: Determine whether the voltage difference between the first voltage and the second voltage is greater than a first preset threshold;

[0029] S30: If yes, obtain the current operating condition;

[0030] S41: When the current operating condition is a discharging condition, a discharging balancing operation is performed;

[0031] S42: When the current operating condition is a charging condition, performing a charging balancing operation;

[0032] S43: When the current operating condition is the standby condition, performing a standby balancing operation;

[0033] S50: Turn on the first battery cluster and the second battery cluster.

[0034] See also Figure 2 The control method provided in the embodiment of the present invention is applied to a dual-branch high-power energy storage battery system, which includes a first power supply branch and a second power supply branch, the first power supply branch is connected to a first battery cluster, and the second power supply branch is connected to a second battery cluster, so that multiple battery clusters can be comprehensively controlled and managed through a main control unit, effectively reducing the number of control cabinets required when multiple battery clusters are used for energy storage, reducing space occupancy, improving the energy density of the energy storage battery system, and reducing enterprise operating costs.

[0035] During use, since multiple battery clusters are connected in parallel, and since the internal resistance of each battery cell is very small, the internal resistance of the entire battery cluster is also very small. When there is a voltage difference between different battery clusters, even a voltage difference of only a few volts may cause a circulating current of thousands of amperes, causing the relay to stick or damage the battery cell, and even further leading to a safety accident. Therefore, it cannot meet actual needs.

[0036] In order to solve the above technical problems, during use, the access of the first battery cluster and the second battery cluster is controlled. Specifically, when the above energy storage battery system needs to be used, the first voltage of the first battery cluster and the second voltage of the second battery cluster are first obtained and compared to determine whether the voltage difference between the first voltage and the second voltage is greater than a first preset threshold. In an embodiment of the present invention, the first preset threshold is determined in advance according to the maximum voltage difference of the current energy storage battery system. If the voltage difference between the battery clusters exceeds the maximum voltage difference, the generated circulating current may damage the cells in the battery cluster.

[0037] In the specific implementation process, a threshold value can be pre-set by a technician based on actual experience as the first preset threshold value. However, due to the different production and manufacturing conditions and physical properties of each battery, their internal resistances are also different. Therefore, the use of a fixed setting method will inevitably have deviations and therefore cannot meet actual needs.

[0038] In an embodiment of the present invention, the method further includes: obtaining a preset safety loop current and determining the internal resistance value of each battery cluster; determining the maximum voltage difference between clusters based on the preset safety loop current and the internal resistance value of each battery cluster; and determining the maximum voltage difference as the first preset threshold.

[0039] In a possible implementation, the maximum voltage difference allowed to be connected to each battery cluster is determined according to its actual situation. Specifically, a preset safety loop current is first obtained, for example, the preset safety loop current is the maximum acceptable input / output current of the battery cell provided by the battery cell manufacturer. At this time, the actual internal resistance value of each battery cluster needs to be further accurately determined.

[0040] In an embodiment of the present invention, determining the internal resistance value of each battery cluster includes: determining the ambient temperature and a preset collection interval; determining a plurality of internal resistance collection capacity points based on the preset collection interval; calibrating the unit discharge current of each battery cell to obtain a calibrated discharge current; performing an internal resistance detection operation at each internal resistance collection capacity point based on the calibrated discharge current to obtain an internal resistance value corresponding to each internal resistance collection capacity point; determining an average internal resistance of each battery cell based on the internal resistance values ​​corresponding to all internal resistance collection capacity points; and determining the internal resistance of the battery cluster based on the ambient temperature and the average internal resistance.

[0041] In a possible implementation, since different ambient temperatures will also affect the internal resistance of the battery cell, the ambient temperature and the preset collection interval are first determined. For example, in this embodiment, in order to improve the detection accuracy of the internal resistance of the battery cell, the internal resistance value of the battery cell is obtained once every 5% of the capacity value, that is, the preset collection interval is 5%, that is, in this embodiment, it is necessary to collect the internal resistance value of the current battery cell at each internal resistance collection capacity point of 0%, 5%, 10%...90%, 95%, and 100% to ensure the accuracy of its internal resistance detection. Before detecting the internal resistance value of the battery cell, in order to avoid the situation where the actual unit discharge current of the battery cell is inconsistent with the rated discharge current, it is also necessary to calibrate the unit discharge current (1C) of each battery cell and determine the corresponding calibrated discharge current. The calibration method familiar to those skilled in the art can be used for calibration, and no further details will be given here. At this time, the detection of the internal resistance value begins.

[0042] In an embodiment of the present invention, the internal resistance detection operation includes: performing a full discharge operation on the current battery cell based on the calibrated discharge current; placing the battery cell for a first time to obtain a fully discharged battery cell, and obtaining a first internal resistance of the fully discharged battery cell, the first time being determined based on the discharge temperature rise data and physical stability data of the current battery cell; performing a full charge operation on the fully discharged battery cell based on the calibrated discharge current; placing the battery cell for a second time to obtain a fully charged battery cell, and obtaining a second internal resistance of the fully charged battery cell, the second time being determined based on the charging temperature rise data and the physical stability data of the current battery cell; determining an upper limit value and a lower limit value of the maximum discharge current, based on Perform a discharge operation on the fully charged battery cell according to the upper limit value at the preset detection time; place the battery cell for a third time to obtain a controlled-discharge battery cell, and obtain a third internal resistance of the controlled-discharge battery cell, wherein the third time is determined based on the preset detection time, the discharge temperature rise data and the physical stability data; perform a charging operation on the controlled-discharge battery cell according to the lower limit value based on the preset detection time; place the battery cell for the third time to obtain a controlled-charge battery cell, and obtain a fourth internal resistance of the controlled-charge battery cell; determine the internal resistance value of the current battery cell at the current internal resistance acquisition capacity point based on the first internal resistance, the second internal resistance, the third internal resistance and the fourth internal resistance.

[0043] In a possible implementation, since the actual capacity of the current battery cell is unclear, a full discharge operation is first performed on the current battery cell based on a calibrated discharge current. Specifically, for example, if the calibrated discharge current is 1C, the current battery cell is discharged at 1C until the voltage of the current battery cell reaches the termination voltage. On the one hand, the battery cell will release heat during discharge, and the temperature will affect the internal resistance of the battery cell; on the other hand, after the battery cell is discharged to the termination voltage, due to internal chemical reactions, there will be a voltage rebound during the placement process, which will cause a deviation in the internal resistance detection. Therefore, after the discharge is completed, the current battery cell is placed for a first time (for example, 30 minutes) to obtain a fully discharged battery cell. The first time is comprehensively determined based on the discharge temperature rise data of the current battery cell (that is, how much the temperature of the battery cell will change due to full discharge) and the physical stability data (that is, its chemical stability). For example, in this embodiment, it is necessary to keep the temperature of the current battery cell in a stable state (for example, the same as or close to room temperature), and the voltage in a stable state. At this time, the first internal resistance of the current battery cell is detected and obtained.

[0044] Then, based on the calibrated discharge current, the fully discharged cell is fully charged to reach a fully charged state. In a specific implementation, it can be first charged at 1C, and when it reaches the charge termination voltage, it is changed to constant voltage charging until the current is less than or equal to a given cutoff current (for example, 0.1C~0.05C), and the full charging operation is determined to be completed. At this time, based on the same principle, but because the cell generates more heat during the charging process and its internal chemical stability is weaker in the fully charged state, it is placed for a second time (for example, 60 minutes) to obtain a fully charged cell, and its second internal resistance is further obtained at this time.

[0045] Then, the internal resistance is further detected under the condition of maximum discharge. Specifically, the upper limit and lower limit of the maximum discharge current are first determined. For example, in an embodiment of the present invention, the maximum discharge current of the battery cell when it leaves the factory is determined as its upper limit, such as 2C, and the maximum discharge current of the battery cell when it reaches its service life (for example, its capacity decays to 70% of that when it leaves the factory) is determined as its lower limit, such as 1.4C. At this time, the charging operation is performed on the fully charged battery cell according to the above upper limit, and the discharging operation is performed according to the preset detection time. For example, in this embodiment, it is considered that discharging for 10s can reflect the influence of the discharge process on the internal resistance of the battery cell, that is, the preset detection time is determined to be 10s. At this time, the current battery cell is placed for a third time to obtain a controlled discharged battery cell, and its third internal resistance is obtained at this time. And further, according to the lower limit of the maximum discharge current, the charging operation is performed on the controlled discharged battery cell within the preset detection time. Since the preset detection time is short, it can be considered that the placement time required for its stability is the same, so the current battery cell is placed for a third time to obtain a controlled charged battery cell, and its fourth internal resistance is obtained.

[0046] On this basis, in order to further improve the detection accuracy of the internal resistance of the battery cell, the above-mentioned operation of discharging according to the upper limit value and charging according to the lower limit value can be repeated, for example, 15-25 times, to collect more abundant internal resistance data. Finally, the internal resistance obtained above is averaged to obtain the internal resistance value of the current battery cell at the current internal resistance collection capacity point.

[0047] Repeat the above operation to obtain the internal resistance value of the current battery cell at each internal resistance collection capacity point, and finally determine its average internal resistance during the charging process and the discharging process. For example, in one embodiment, it is detected that the average internal resistance value of the current battery cell is 0.8263 mΩ, the average internal resistance value of the charging is: 0.7540 mΩ, and the average internal resistance value of the charging and discharging battery cell is 0.7902 mΩ. At this time, further, according to how many of the above-mentioned battery cells are contained in the current battery cluster, and their connection methods, combined with the internal resistance of other electrical connectors (such as aluminum bars, etc.) in each battery cluster, for example, it is estimated to be 2 mΩ, and the internal resistance of the current battery cluster is calculated. For example, in this embodiment, the internal resistance of all battery cells is 268.8 mΩ, the internal resistance of the internal electrical connector is 2 mΩ, and the contact impedance of the line and the connector is 1.5 mΩ, then the impedance of the branch where the entire battery cluster is located is about 270 mΩ. In general, the above detection operation is performed at a standard ambient temperature (for example, 20-30°). If the current ambient temperature is not the standard ambient temperature, the internal resistance value detected above can be converted according to a preset conversion factor to obtain the accurate internal resistance of the battery cell.

[0048] After obtaining the internal resistance value of each battery cluster, for example, in this embodiment, if the internal resistance value of the branch where the battery cluster is located is 0.27Ω, the branch voltage difference will differ by 1V, and there will be a circulating current of 1 / 0.27=3.7A causing loss, that is, the power loss is 3.7W. For the energy storage battery system, the voltage difference between different branches can easily reach 3-5V, resulting in a large amount of energy waste. When the voltage difference is too large, it may even generate a very large circulating current that causes certain damage to the battery cell.

[0049] In the embodiment of the present invention, after the internal resistance value of each battery cluster is determined, the maximum voltage difference between the clusters can be determined according to the preset safety loop current and the internal resistance value, and the maximum voltage difference between the clusters is set to the first preset threshold value. That is, an accurate voltage difference threshold is determined for each battery cluster according to its actual situation, which greatly improves the control accuracy, effectively avoids the critical overcurrent risk due to the individual differences of each battery cluster, and improves the safety of the energy storage battery system.

[0050] After determining the threshold of each battery cluster, in the subsequent use process, the voltage difference between each battery cluster and the adjacent battery cluster can be calculated. If the voltage difference is greater than the first preset threshold, the battery cluster with lower voltage is not directly connected, but the voltage balancing operation is performed first, and then connected step by step to ensure its safety in use.

[0051] In an embodiment of the present invention, the first power supply branch includes a first conduction circuit and a first current reduction circuit arranged in parallel with each other, and the second power supply branch includes a second conduction circuit and a second current reduction circuit arranged in parallel with each other, and the performing of the discharge balancing operation includes: determining a high-voltage battery cluster with a higher voltage and a low-voltage battery cluster with a lower voltage based on the first voltage and the second voltage; connecting the conduction circuit corresponding to the high-voltage battery cluster until the voltage difference between the high-voltage battery cluster and the low-voltage battery cluster is less than or equal to the first preset threshold value; and the performing of the charge balancing operation includes: connecting the conduction circuit corresponding to the low-voltage battery cluster until the voltage difference between the low-voltage battery cluster and the high-voltage battery cluster is less than or equal to the first preset threshold value.

[0052] In a possible implementation, before the energy storage battery system is about to be used, if it is detected that the voltage between its battery clusters exceeds the maximum voltage difference between the clusters, the corresponding voltage balancing operation is performed according to its actual working condition. Specifically, the high-voltage battery cluster and the low-voltage battery cluster are determined according to the first voltage and the second voltage corresponding to the battery cluster. For the discharge working condition, the conduction circuit corresponding to the high-voltage battery cluster is first connected to discharge the high-voltage battery cluster first, until the voltage difference between its voltage and the low-voltage battery cluster is less than or equal to the first preset threshold, and then the conduction circuits of the two battery clusters are simultaneously connected to achieve the effect of the same voltage and parallel output. For the charging working condition, the opposite logic is adopted, and the conduction circuit corresponding to the low-voltage battery cluster is first connected to charge the low-voltage battery cluster first, until the voltage difference between its voltage and the high-voltage battery cluster is less than or equal to the first preset threshold, and then the conduction circuits of the two battery clusters are simultaneously connected to achieve the effect of the same voltage and parallel input.

[0053] For standby conditions, it is mainly because the battery cluster has been placed for too long, and its different degrees of natural discharge lead to a voltage difference. In order to avoid excessive circulating current damaging the battery, it needs to be actively balanced.

[0054] In an embodiment of the present invention, the execution of the standby balancing operation includes: controlling the current reduction circuit corresponding to the low-voltage battery cluster to be turned on, and controlling the conduction circuit corresponding to the high-voltage battery cluster to be turned on; real-time monitoring whether the voltage difference between the low-voltage battery cluster and the high-voltage battery cluster is less than a second preset threshold; if so, determining that the standby balancing operation is completed, and the second preset threshold is less than the first preset threshold.

[0055] In a possible implementation, firstly, the current reduction circuit corresponding to the low-voltage battery cluster is controlled to be turned on, and the conduction circuit corresponding to the high-voltage battery cluster is controlled to be turned on. In the embodiment of the present invention, the current reduction circuit may include but is not limited to components such as voltage divider resistors and transistors, which are used to reduce the current flowing through the loop to protect the battery cells. Through the above control method, the high-voltage battery cluster is allowed to charge the low-voltage battery cluster with a lower current, and at the same time, the voltage divider resistor consumes electric energy, so that the voltage between the two battery clusters is kept consistent as soon as possible.

[0056] During the discharge process, since the first preset threshold is the maximum voltage difference that does not cause damage to the battery cell, and the technicians expect the battery cluster to be able to charge and discharge as uniformly as possible, after determining the first preset threshold, the second preset threshold can be further determined. The second preset threshold is smaller than the first preset threshold and can be pre-set by the technicians according to actual conditions.

[0057] During the discharge process, the voltage difference between the two battery clusters is monitored in real time to see if it is less than a second preset threshold value. When it is detected that the voltage difference is less than the second preset threshold value, it is determined that the standby balancing operation is completed. At this time, the current reduction circuit corresponding to the low-voltage battery cluster can be closed and its conduction circuit can be turned on to use two battery clusters for output at the same time, thereby realizing the circulation control of the dual-branch battery cluster, allowing multiple battery clusters to be connected in parallel to the same battery management system for management, meeting actual use needs and improving the safety of the dual-branch energy storage battery system.

[0058] It should be noted that in the embodiment of the present invention, a high-power energy storage battery system with two branches is a preferred embodiment. For those skilled in the art, based on the embodiment of the present invention, it is possible to conceive of adopting a multi-branch energy storage battery system with more than two branches, which is a conventional expansion method and therefore also falls within the scope of protection of the present invention, and will not be elaborated on herein.

[0059] In the process of configuring the current reduction circuit, in order to meet the full current reduction effect when performing the standby balancing operation, it is necessary to configure a precise current reduction resistor to ensure that when the high voltage battery cluster is connected, the current flowing through the branch can be controlled within a safe range.

[0060] In an embodiment of the present invention, the first current drop circuit includes a first current drop resistor, the second current drop circuit includes a second current drop resistor, and the control method further includes: determining the resistance value of the first current drop resistor based on the preset safety loop current, the internal resistance of the first battery cluster and the rated voltage, and configuring the first current drop resistor in the first current drop circuit; determining the resistance value of the second current drop resistor based on the preset safety loop current, the internal resistance of the second battery cluster and the rated voltage, and configuring the second current drop resistor in the second current drop circuit.

[0061] In a possible implementation, the maximum output current of the battery cluster under short-circuit conditions can be calculated based on the calculated internal resistance of the first battery cluster and the rated voltage of the battery cluster. Combined with the preset safety loop current, the maximum resistance value of the resistor that needs to be configured in the power circuit of the battery cluster under short-circuit conditions can be determined. Since the voltage difference between battery clusters is often within a limited range in actual applications, the maximum voltage difference between battery clusters can be determined based on experience according to the rated voltage of the battery cluster, and the maximum resistance value of the resistor that needs to be configured can be determined, that is, the first current drop resistor of the first battery cluster and the second current drop resistor of the second battery cluster are determined. On this basis, when standby balancing operation is required, it can be ensured that the current between the two battery clusters is within a safe range, and the power of the high-voltage battery cluster can be appropriately consumed, thereby ensuring the safety of the energy storage battery system.

[0062] See also Figure 3 Based on the same inventive concept, an embodiment of the present invention provides a control device for a dual-branch high-power energy storage battery system, wherein the dual-branch high-power energy storage battery system comprises a first power supply branch and a second power supply branch, wherein the first power supply branch is connected to a first battery cluster, and the second power supply branch is connected to a second battery cluster, and the control device comprises: a voltage acquisition unit, configured to acquire a first voltage of the first battery cluster and a second voltage of the second battery cluster; a judgment unit, configured to judge whether a voltage difference between the first voltage and the second voltage is greater than a first preset threshold; an operating condition acquisition unit, configured to acquire a current operating condition when the voltage difference is greater than the first preset threshold; a first balancing unit, configured to perform a discharge balancing operation when the current operating condition is a discharge condition; a second balancing unit, configured to perform a charge balancing operation when the current operating condition is a charge condition; a third balancing unit, configured to perform a standby balancing operation when the current operating condition is a standby condition; and a connection control unit, configured to connect the first battery cluster and the second battery cluster.

[0063] Furthermore, an embodiment of the present invention further provides a processor for running a program, wherein the program, when being run, is used to execute the control method described in the embodiment of the present invention.

[0064] Furthermore, an embodiment of the present invention also provides a computer-readable storage medium on which a computer program is stored, and when the program is executed by a processor, the control method of the present invention is implemented.

[0065] The optional implementation modes of the embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above implementation modes. Within the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical scheme of the embodiments of the present invention, and these simple modifications all belong to the protection scope of the embodiments of the present invention.

[0066] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not further describe various possible combinations.

[0067] Those skilled in the art can understand that all or part of the steps in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a program, and the program is stored in a storage medium, including a number of instructions to enable a single-chip microcomputer, a chip or a processor to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0068] In addition, various implementation modes of the embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the embodiments of the present invention, they should also be regarded as the contents disclosed by the embodiments of the present invention.

Claims

1. A control method for a dual-branch high-power energy storage battery system, characterized in that: The dual-branch high-power energy storage battery system includes a first power supply branch and a second power supply branch, the first power supply branch is connected to a first battery cluster, and the second power supply branch is connected to a second battery cluster. The control method includes: acquiring a first voltage of the first battery cluster and a second voltage of the second battery cluster; Determining whether a voltage difference between the first voltage and the second voltage is greater than a first preset threshold; If yes, obtain the current operating conditions; When the current operating condition is a discharge condition, a discharge balancing operation is performed; When the current operating condition is a charging condition, a charging balancing operation is performed; When the current operating condition is the standby condition, a standby balancing operation is performed; connecting the first battery cluster and the second battery cluster; Obtain the preset safety loop current and determine the internal resistance value of each battery cluster; Determining the internal resistance value of each battery cluster includes: Determine the ambient temperature and preset collection interval; Determining a plurality of internal resistance acquisition capacity points based on the preset acquisition interval; Calibrate the unit discharge current of each battery cell to obtain the calibrated discharge current; Performing an internal resistance detection operation at each internal resistance acquisition capacity point based on the calibrated discharge current to obtain an internal resistance value corresponding to each internal resistance acquisition capacity point; Determine the average internal resistance of each battery cell based on the internal resistance values ​​corresponding to all internal resistance acquisition capacity points; An internal resistance of a battery cluster is determined based on the ambient temperature and the average internal resistance.

2. The control method according to claim 1, characterized in that: The control method further comprises: Determining a maximum voltage difference between clusters based on the preset safety loop current and an internal resistance value of each battery cluster; The maximum pressure difference is determined as the first preset threshold.

3. The control method according to claim 1, characterized in that: The performing of the internal resistance detection operation includes: Performing a full discharge operation on the current battery cell based on the calibrated discharge current; Placing the battery cell for a first time to obtain a fully discharged battery cell, and obtaining a first internal resistance of the fully discharged battery cell, wherein the first time is determined based on discharge temperature rise data and physical stability data of the current battery cell; Performing a full charging operation on the fully discharged battery cell based on the calibrated discharge current; Placing the battery cell for a second time to obtain a fully charged battery cell, and obtaining a second internal resistance of the fully charged battery cell, wherein the second time is determined based on the charging temperature rise data of the current battery cell and the physical stability data; Determine an upper limit value and a lower limit value of a maximum discharge current, and perform a discharge operation on the fully charged battery cell according to the upper limit value based on a preset detection time; placing the battery cell for a third time to obtain a controlled-discharged battery cell, and obtaining a third internal resistance of the battery cell after the controlled-discharge, wherein the third time is determined based on the preset detection time, the discharge temperature rise data, and the physical stability data; Performing a charging operation on the controlled-discharged battery cell according to the lower limit value based on the preset detection time; Placing the battery cell for the third time to obtain a controlled charged battery cell, and obtaining a fourth internal resistance of the battery cell after the controlled charged battery cell; An internal resistance value of a current battery cell at a current internal resistance acquisition capacity point is determined based on the first internal resistance, the second internal resistance, the third internal resistance, and the fourth internal resistance.

4. The control method according to claim 1, characterized in that: The first power supply branch includes a first conduction circuit and a first current reduction circuit arranged in parallel with each other, the second power supply branch includes a second conduction circuit and a second current reduction circuit arranged in parallel with each other, and the performing of the discharge balancing operation includes: determining a high-voltage battery cluster with a higher voltage and a low-voltage battery cluster with a lower voltage based on the first voltage and the second voltage; Turning on the conduction circuit corresponding to the high-voltage battery cluster until the voltage difference between the high-voltage battery cluster and the low-voltage battery cluster is less than or equal to the first preset threshold; The performing of the charging balancing operation comprises: The conduction circuit corresponding to the low-voltage battery cluster is turned on until the voltage difference between the low-voltage battery cluster and the high-voltage battery cluster is less than or equal to the first preset threshold.

5. The control method according to claim 4, characterized in that: The performing of the standby balancing operation comprises: Controlling the current reduction circuit corresponding to the low voltage battery cluster to be turned on, and controlling the conduction circuit corresponding to the high voltage battery cluster to be turned on; monitoring in real time whether the voltage difference between the low-voltage battery cluster and the high-voltage battery cluster is less than a second preset threshold; If so, it is determined that the standby balancing operation is completed, and the second preset threshold is less than the first preset threshold.

6. The control method according to claim 5, characterized in that: The first current reduction circuit includes a first current reduction resistor, the second current reduction circuit includes a second current reduction resistor, and the control method further includes: determining a resistance value of the first current reducing resistor based on the preset safety loop current, the internal resistance of the first battery cluster and the rated voltage, and configuring the first current reducing resistor in the first current reducing circuit; The resistance value of the second current reducing resistor is determined based on the preset safety loop current, the internal resistance of the second battery cluster and the rated voltage, and the second current reducing resistor is configured in the second current reducing circuit.

7. A control device for a dual-branch high-power energy storage battery system, characterized in that: The dual-branch high-power energy storage battery system includes a first power supply branch and a second power supply branch, the first power supply branch is connected to a first battery cluster, the second power supply branch is connected to a second battery cluster, and the control device includes: a voltage acquisition unit, configured to acquire a first voltage of the first battery cluster and a second voltage of the second battery cluster; a judging unit, configured to judge whether a voltage difference between the first voltage and the second voltage is greater than a first preset threshold; A working condition acquisition unit, used for acquiring the current operating condition when the pressure difference is greater than the first preset threshold; A first balancing unit, used for performing a discharge balancing operation when the current operating condition is a discharge condition; A second balancing unit, used for performing a charging balancing operation when the current operating condition is a charging condition; A third balancing unit, used for performing a standby balancing operation when the current operating condition is a standby condition; A connection control unit, used for connecting the first battery cluster and the second battery cluster; The control device is also used for: Obtain the preset safety loop current and determine the internal resistance value of each battery cluster; Determining the internal resistance value of each battery cluster includes: Determine the ambient temperature and preset collection interval; Determining a plurality of internal resistance acquisition capacity points based on the preset acquisition interval; Calibrate the unit discharge current of each battery cell to obtain the calibrated discharge current; Performing an internal resistance detection operation at each internal resistance acquisition capacity point based on the calibrated discharge current to obtain an internal resistance value corresponding to each internal resistance acquisition capacity point; Determine the average internal resistance of each battery cell based on the internal resistance values ​​corresponding to all internal resistance acquisition capacity points; An internal resistance of a battery cluster is determined based on the ambient temperature and the average internal resistance.

8. A processor, characterized in that: Used to run a program, wherein the program is used to execute the control method according to any one of claims 1 to 6 when being run.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the control method described in any one of claims 1 to 6 is implemented.

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