All-vanadium redox flow battery system stack equalization control method and device, storage medium and computer equipment

Abstract

The application discloses a method and device for equalizing control of an electric pile in a vanadium redox flow battery system, a storage medium and computer equipment. The method comprises the following steps: in response to the vanadium redox flow battery system being in a charging state, acquiring voltage values of each electric pile in the vanadium redox flow battery system. Then, the electric pile with the highest voltage value in the vanadium redox flow battery system is determined as a first electric pile. In the case that the difference between the voltage value of the first electric pile and the average voltage value is greater than a first preset voltage difference value, the discharging control of the first electric pile is repeatedly performed until the difference between the voltage value of the first electric pile and the average voltage value after discharging is less than or equal to a second preset voltage difference value, and the discharging control of the first electric pile is stopped. The second preset voltage difference value is less than the first preset voltage difference value. The embodiments of the application can realize the equalizing control of the voltage of each electric pile in the vanadium redox flow battery system.

Description

Technical Field

[0001] This application relates to the field of vanadium redox flow battery management technology, and in particular to a method, apparatus, storage medium and computer equipment for stack balancing control in a vanadium redox flow battery system. Background Technology

[0002] With the rapid development of the energy storage industry, vanadium redox flow batteries have gradually become the mainstream technology in the field. To meet the demands of high voltage and high power output, a multi-stack series-parallel architecture is commonly used. Due to differences in pipeline resistance, the electrolyte supply flow rate of each series-connected stack is difficult to maintain. After long-term cyclic operation, the voltage of each stack gradually develops discrete deviations, leading to stack imbalance problems.

[0003] However, inconsistent stack voltages can reduce system capacity utilization and charge / discharge efficiency, and in severe cases, exacerbate stack overcharging and trigger multi-level system protection shutdowns. Therefore, how to achieve stable control of the voltage of each stack to ensure the continuous and reliable operation of the vanadium redox flow battery system has become an urgent problem to be solved. Summary of the Invention

[0004] In view of this, embodiments of this application provide a method, apparatus, storage medium, and computer equipment for equalizing the stacks in a vanadium redox flow battery system, which can achieve stable control of the voltage of each stack, thereby ensuring the continuous and reliable operation of the vanadium redox flow battery system.

[0005] In a first aspect, this application provides a method for stack equalization control in an all-vanadium redox flow battery system, including: In response to the vanadium redox flow battery system being in a charging state, the voltage values ​​of each stack in the vanadium redox flow battery system are obtained; The stack with the highest voltage value in the all-vanadium redox flow battery system is designated as the first stack. If the difference between the voltage value of the first battery stack and the average voltage value is greater than the first preset voltage difference, the discharge control of the first battery stack is repeatedly executed until the difference between the voltage value of the first battery stack and the average voltage value after discharge is less than the second preset voltage difference, and the discharge control of the first battery stack is stopped; wherein, the second preset voltage difference is less than the first preset voltage difference.

[0006] Secondly, this application provides a stack balancing control device for an all-vanadium redox flow battery system, comprising: The voltage acquisition module is used to acquire the voltage values ​​of each stack in the vanadium redox flow battery system in response to the vanadium redox flow battery system being in a charging state. The stack determination module is used to determine the stack with the highest voltage value in the vanadium redox flow battery system as the first stack. The electric propulsion control module is used to repeatedly perform discharge control on the first electric stack when the difference between the voltage value of the first electric stack and the average voltage value is greater than a first preset voltage difference, until the difference between the voltage value of the first electric stack and the average voltage value after discharge is less than a second preset voltage difference, and then stop the discharge control of the first electric stack; wherein, the second preset voltage difference is less than the first preset voltage difference.

[0007] Thirdly, this application provides a storage medium storing a computer program thereon, which, when executed by a processor, implements the above-described method for equalizing the stack within a vanadium redox flow battery system.

[0008] Fourthly, this application provides a computer device, including a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, wherein the processor executes the program to implement the above-described vanadium redox flow battery system internal stack equalization control method.

[0009] By utilizing the above technical solutions, the embodiments of this application provide a method, apparatus, storage medium, and computer device for equalizing the stacks in a vanadium redox flow battery system. Responding to the charging state of the battery system, the voltage of each stack is collected, and the stack with the highest voltage is locked as the correction target. Discharge equalization control is continuously applied to this high-voltage stack until the difference between its voltage and the average voltage of the stack meets a threshold requirement, at which point the equalization operation stops. This method can accurately target and correct abnormal stacks with excessively high voltages during charging, eliminating the need for uniform adjustment of all stacks and avoiding unnecessary losses to normal stacks. Through multiple gradual discharges, the voltage difference between stacks gradually converges, effectively reducing the voltage dispersion between series-connected stacks, alleviating stack imbalance problems, preventing electrolyte valence imbalance and accelerated aging of electrode membranes caused by continuous overcharging of high-voltage stacks, reducing the probability of triggering multi-level alarm shutdowns due to excessive stack voltage differences, and improving the charging and discharging efficiency, capacity utilization, and long-term operational stability of the vanadium redox flow battery system.

[0010] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0011] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 A schematic diagram of the topology of a fuel cell stack equalization control circuit provided in an embodiment of this application is shown; Figure 2A schematic flowchart of a stack equalization control method for an all-vanadium redox flow battery system provided in an embodiment of this application is shown. Figure 3 A schematic flowchart of another vanadium redox flow battery system stack equalization control method provided in an embodiment of this application is shown; Figure 4 This paper shows a schematic diagram of the structure of a stack equalization control device in an all-vanadium redox flow battery system according to an embodiment of this application; Figure 5 A schematic diagram of the structure of another vanadium redox flow battery system stack balancing control device provided in an embodiment of this application is shown. Detailed Implementation

[0012] To facilitate the explanation of the embodiments of this application, some technical terms and technical means related to the embodiments of this application, as well as the application scenarios of the embodiments of this application, will be introduced first below.

[0013] In some cases, due to the large number of electrolyte stacks within a vanadium redox flow battery (vanadium redox flow battery) and the presence of leakage current, the currents of the stacks connected in series within the battery cannot be completely synchronized. This makes it difficult to maintain a consistent electrolyte supply flow rate across the stacked electrolyte lines. After long-term cyclic operation, voltage differences will develop among the stacks. If no timely measures are taken, these voltage differences will gradually increase. Consequently, when the vanadium redox flow battery system is charging, the stack with the highest voltage will reach its upper voltage limit first, while when the system is discharging, the stack with the lowest voltage will reach its lower voltage limit first, ultimately causing the entire vanadium redox flow battery system to malfunction.

[0014] Correspondingly, to ensure the normal operation of the vanadium redox flow battery system, in the event of an abnormal voltage in any stack within the system, the faulty stack will be manually replaced to resolve the stack imbalance issue. However, this consumes a significant amount of manpower and resources, increasing the operation and maintenance costs of the vanadium redox flow battery system, and in severe cases, it can even affect the system's operating time.

[0015] Therefore, in order to reduce the operation and maintenance costs of a vanadium redox flow battery system while achieving stable voltage control of each stack, this application provides a stack equalization control method within a vanadium redox flow battery system, applied to the voltage control scenario of stacks within a vanadium redox flow battery system. In this method, in response to the vanadium redox flow battery system being in a charging state, the voltage values ​​of each stack within the vanadium redox flow battery system are acquired. Then, the stack with the highest voltage value within the vanadium redox flow battery system is determined as the first stack. Subsequently, if the difference between the voltage value of the first stack and the average voltage value is greater than a first preset voltage difference, discharge control of the first stack is repeatedly executed until, after discharge, the difference between the voltage value of the first stack and the average voltage value is less than or equal to a second preset voltage difference, at which point the discharge control of the first stack stops; wherein, the second preset voltage difference is less than the first preset voltage difference.

[0016] In this embodiment, in response to the battery system charging status, the voltage of each stack is collected, and the stack with the highest voltage is locked as the correction target. The high-voltage stack is continuously subjected to discharge equalization control until the difference between its voltage and the average voltage of the stack meets the threshold requirement, at which point the equalization operation stops. This can accurately target and correct abnormal stacks with high voltage under charging conditions without uniformly adjusting all stacks, avoiding unnecessary losses to normal stacks. Through multiple gradual discharges, the voltage difference between stacks is gradually converged, effectively reducing the voltage dispersion between series stacks, alleviating stack imbalance problems, preventing electrolyte valence imbalance and accelerated aging of electrode membranes caused by continuous overcharging of high-voltage stacks, reducing the probability of triggering multi-level alarm shutdowns due to excessive stack voltage difference, and improving the charge and discharge efficiency, capacity utilization, and long-term operational stability of the vanadium redox flow battery system.

[0017] The present application will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present application can be combined with each other.

[0018] Figure 1 This is a topology diagram of a battery stack balancing control circuit provided in an embodiment of this application. The battery stack balancing control circuit includes a direct current (DC) bus 110, a DC / DC converter 120, bypass branches 130, and a vanadium redox flow battery system 140. The DC / DC converter 120 includes multiple branches, each corresponding to a group of battery cells in the vanadium redox flow battery system 140. Each group of battery cells corresponds to two battery stacks connected in parallel. Furthermore, each branch can independently control the charging and discharging of its corresponding battery cells, and the branch current direction is completely independent. In other words, the DC / DC converter 120 can support some branches to perform charging functions and others to perform discharging functions.

[0019] The bypass branch 130 includes a current-limiting resistor 131 and a bypass switch 132. The bypass switch 132 can be a DC contactor with a coil voltage of DC 24V. Furthermore, considering the system cost and actual operating conditions of the vanadium redox flow battery system 140, the maximum charge / discharge current of the bypass branch 130 is 1 / 100 to 1 / 50 of the rated operating current of the battery stack. For example, taking a constant current of 300 amperes (A) for the vanadium redox flow battery system 140, the maximum charge / discharge current of the bypass branch 130 can be 1 / 50 × 300 = 6 A.

[0020] The aforementioned vanadium redox flow battery system 140 may include eight stacks 141, consisting of two stack groups connected in parallel and four stacks in each stack group connected in series. Each stack 141 is equipped with a corresponding stack identifier to facilitate automatic identification of faulty stacks in case of abnormal stack voltage. It can be seen that the vanadium redox flow battery system 140 is connected to the DC bus 110 via a DC / DC converter 120 to step down the bus power during the charging phase for charging and discharging each stack.

[0021] In some cases, the aforementioned vanadium redox flow battery system 140 also includes a vanadium redox flow battery management system. This management system can be used to collect and store the operating parameters of the vanadium redox flow battery system 140. In some embodiments of this application, the operating parameters can be the voltage values ​​of each battery stack within the vanadium redox flow battery system 140. In other embodiments, the operating parameters may also include total pipeline flow rate, total pipeline pressure, electrolyte temperature, positive and negative electrode tank levels, circulating pump current, circulating pump speed, battery string voltage, current in each branch, state of charge, electric valve status, alarm information, etc.

[0022] Correspondingly, the vanadium redox flow battery management system can establish a communication connection with the DC / DC converter 120 via the Modbus communication protocol. The vanadium redox flow battery management system acts as the control center, and the various branches of the DC / DC converter 120 act as execution units, so that the vanadium redox flow battery management system can send charging and discharging current values ​​and start / stop signals to each branch.

[0023] It should be noted that the execution entity of the aforementioned vanadium redox flow battery management system can be a computer device. For example, the computer device can be a mobile phone, tablet computer, desktop computer, laptop computer, handheld computer, notebook computer, ultra-mobile personal computer (UMPC), netbook, etc. The embodiments of this application do not impose any special restrictions on the specific form of the computer device.

[0024] Specifically, the current flow of the above-mentioned stack balancing control circuit under charging conditions is as follows: it is output from the DC bus 110, flows sequentially through the positive terminal of the DC / DC converter 120, the bypass branch 130, and the vanadium redox flow battery system 140, and then flows back to the DC bus 110 through the inside of the DC / DC converter 120, forming a complete charging circuit.

[0025] Furthermore, this embodiment provides a method for stack balancing control within a vanadium redox flow battery system, such as... Figure 2 As shown, the method includes: S201, in response to the vanadium redox flow battery system being in a charging state, acquires the voltage values ​​of each stack in the vanadium redox flow battery system.

[0026] Specifically, after the aforementioned vanadium redox flow battery system is in a charging state, the voltage values ​​of each stack within the vanadium redox flow battery system are collected.

[0027] In some cases, considering that various abnormal operating conditions of different severity, such as stack voltage deviation, may occur during the operation of a vanadium redox flow battery system, the vanadium redox flow battery management system can provide graded alarm protection functions. That is, the vanadium redox flow battery management system can execute different levels of alarm protection operations based on the severity of the abnormal operating conditions. These alarm protection operations can include audible and visual alarm operations, stopping the charging of the vanadium redox flow battery system, and performing emergency protection operations on the vanadium redox flow battery system.

[0028] In one implementation, the vanadium redox flow battery management system can pre-set multiple preset voltage values ​​according to actual conditions, and determine at least two preset voltage ranges based on these preset voltage values. Furthermore, the vanadium redox flow battery management system also pre-sets a preset cumulative duration within the preset voltage range where the stack voltage value falls, based on actual conditions. In some embodiments of this application, the multiple preset voltage values ​​can be divided into a first preset voltage value, a second preset voltage value, and a third preset voltage value, and their corresponding preset voltage ranges can be divided into a first preset voltage range and a second preset voltage range. In other embodiments, the multiple preset voltage values ​​can also be divided into four preset voltage values, five preset voltage values, etc., and the specific number is not limited.

[0029] Furthermore, based on the preset voltage range in which the stack voltage value of the vanadium redox flow battery system is located, and whether the cumulative duration of the stack voltage value within the preset voltage range has reached the preset cumulative duration, the alarm protection operation to be performed is determined.

[0030] In some embodiments, if the voltage value of any stack within the vanadium redox flow battery system falls within a first preset voltage range, and the cumulative duration of this voltage range reaches a preset cumulative duration, an audible and visual alarm is triggered. The lower limit of the first preset voltage range is the first preset voltage value, and the upper limit is a second preset voltage value. In other words, the second preset voltage value is greater than the first preset voltage value. This effectively filters false alarms caused by instantaneous voltage fluctuations, accurately identifies persistent faults where the stack operates under abnormal voltage conditions for extended periods, and promptly alerts maintenance personnel to investigate potential problems such as stack voltage imbalance, vanadium ion valence imbalance in the electrolyte, and abnormal branch control. It also helps eliminate inter-stack voltage differential circulation early, ensuring the capacity utilization and operational safety of the entire vanadium redox flow battery system. Furthermore, the audible and visual alarm provides a clear and conspicuous warning, facilitating rapid location of faulty stacks and enabling equalization and repair by on-site maintenance personnel.

[0031] In other embodiments, if the voltage value of any stack within the vanadium redox flow battery system falls within a second preset voltage range, and the cumulative duration of this voltage range reaches a preset cumulative duration, the vanadium redox flow battery system is controlled to stop charging. The lower limit of the second preset voltage range is the second preset voltage value, and the upper limit is a third preset voltage value. That is, the third preset voltage value is greater than the second preset voltage value. This effectively filters out false shutdowns caused by instantaneous voltage spikes, accurately identifies abnormal overcharging conditions of the stack, and promptly stops charging. This reduces irreversible damage to the stack caused by long-term overpressure, such as electrolyte gas evolution and electrode corrosion, thus preventing safety hazards like leakage and insulation degradation from the source. Simultaneously, by relying on the duration-based determination condition, system operational stability is considered, reducing unnecessary shutdowns while ensuring equipment lifespan and operational safety.

[0032] Specifically, stopping the charging of the vanadium redox flow battery system refers to switching the main charging and discharging circuit within the system. This main charging and discharging circuit is the backbone electrical circuit that carries the high-power electrical energy transmission during charging and discharging. This reliably disconnects the high-voltage charging circuit, quickly terminates the continuous overcharging of the battery stack, effectively avoids irreversible damage caused by overvoltage, and provides safety protection for the entire energy storage system.

[0033] In some embodiments, if the voltage value of any stack within the vanadium redox flow battery system exceeds a third preset voltage value, and the cumulative duration of this voltage exceeding the third preset voltage value reaches a preset cumulative duration, an emergency protection operation is performed on the vanadium redox flow battery system. This eliminates malfunctions caused by transient voltage disturbances, quickly responds to high-risk faults such as severe overvoltage of the stack, promptly cuts off the power circuit to block the overcharging process, prevents irreversible and severe damage to the stack such as severe gas evolution, membrane damage, and electrode corrosion, eliminates major safety risks such as leakage and insulation breakdown, and maximizes the safety of the entire vanadium redox flow battery equipment.

[0034] The aforementioned emergency protection operations may include at least one of the following: disconnecting the external charging / discharging circuit within the vanadium redox flow battery system, stopping the circulation pump within the vanadium redox flow battery system, and closing the electric valves within the vanadium redox flow battery system. The external charging / discharging circuit is an external electrical transmission line used to realize the input and output of electrical energy.

[0035] In another implementation, the vanadium redox flow battery management system can pre-set multiple preset stack pressure differences according to actual conditions, and determine at least two preset stack pressure difference intervals based on these multiple preset stack pressure differences. In some embodiments of this application, the multiple preset stack pressure differences can be divided into a first preset stack pressure difference, a second preset stack pressure difference, and a third preset stack pressure difference, and their corresponding preset stack pressure difference intervals can be divided into a first preset stack pressure difference interval and a second preset stack pressure difference interval. In other embodiments, the multiple preset stack pressure differences can also be divided into four preset stack pressure differences, five preset stack pressure differences, etc., and the specific number is not limited.

[0036] Furthermore, the vanadium redox flow battery management system can calculate the difference between the highest and lowest voltage values ​​within the vanadium redox flow battery system and determine this difference as the target stack pressure difference. Then, the vanadium redox flow battery management system can determine the alarm protection operation to be performed based on the preset stack pressure difference range within which the target stack pressure difference falls.

[0037] In some embodiments, when the target stack voltage difference is within a first preset stack voltage difference range, an audible and visual alarm is triggered. The lower limit of the first preset stack voltage difference range is the first preset stack voltage difference, and the upper limit is a second preset stack voltage difference. That is, the second preset stack voltage difference is greater than the first preset stack voltage difference. This allows for timely identification of moderate voltage inconsistencies among the fuel cells, alerting maintenance personnel to proactively implement balancing controls to prevent problems such as internal circulating currents, overcharging, and undercharging caused by continuously expanding voltage differences. Simultaneously, the voltage difference range helps filter out false alarms caused by instantaneous voltage fluctuations, balancing system stability and equipment protection.

[0038] In other embodiments, the vanadium redox flow battery system stops charging when the target stack pressure difference is within a second preset stack pressure difference range. The lower limit of the second preset stack pressure difference range is the second preset stack pressure difference, and the upper limit is a third preset stack pressure difference. That is, the third preset stack pressure difference is greater than the second preset stack pressure difference. This prevents continuous charging of the high-voltage stack from exacerbating voltage imbalance and generating internal circulating currents, reduces abnormal situations such as electrolyte gas evolution and electrode corrosion caused by overcharging of a single stack, and filters out instantaneous fluctuations, reducing unnecessary downtime and balancing equipment safety with system operational continuity.

[0039] In some other embodiments, when the target stack voltage difference exceeds a third preset stack voltage difference, an emergency protection operation is performed on the vanadium redox flow battery system. This allows for rapid handling of high-risk conditions with severe voltage imbalances in each stack, interrupting the system's charging and discharging power circuits, preventing large circulating currents caused by huge voltage differences from leading to overheating and insulation damage. It also fundamentally prevents permanent damage such as irreversible electrolyte valence state imbalance and membrane corrosion caused by severe overcharging or undercharging of the stacks, effectively avoiding major safety risks such as leakage and equipment failure, and maximizing the protection of the entire battery system.

[0040] S202, the stack with the highest voltage value in the all-vanadium redox flow battery system is determined as the first stack.

[0041] Specifically, after collecting the voltage values ​​of all stacks in the vanadium redox flow battery system, the stack with the highest voltage value in the vanadium redox flow battery system can be identified as the first stack.

[0042] In some cases, the stacks within a vanadium redox flow battery system can be ordered according to their voltage levels. The stack ranked first in this order is then designated as the first stack.

[0043] S203, determine whether the difference between the voltage value of the first stack and the average voltage value is greater than a first preset voltage difference.

[0044] Specifically, after determining the first battery stack, it can be determined whether the difference between the voltage value of the first battery stack and the average voltage value is greater than a first preset voltage difference. The average voltage value is calculated by averaging the voltage values ​​of all battery stacks in the vanadium redox flow battery system. The first preset voltage difference can be preset according to actual conditions. In some embodiments of this application, the first preset voltage difference can be 1V. In other embodiments, the first preset voltage difference can also be 0.8V, etc., and there is no specific limitation.

[0045] In some embodiments, if the difference between the voltage value of the first battery stack and the average voltage value is greater than a first preset voltage difference, it indicates that the voltage of the first battery stack is too high. Therefore, step S204 needs to be performed to reduce the voltage value of the first battery stack.

[0046] In other embodiments, if the difference between the voltage value of the first battery stack and the average voltage value is less than or equal to a first preset voltage difference, it indicates that the voltage differences between the battery stacks are in a balanced state, meaning that the vanadium redox flow battery system will not malfunction due to excessive voltage differences. Therefore, the first battery stack can be de-discharged, and the process can directly return to step S201 to continue monitoring for large voltage differences between battery stacks.

[0047] S204 controls the discharge of the first fuel cell stack.

[0048] Specifically, after determining that the difference between the voltage value of the first energy storage stack and the average voltage value is greater than a first preset voltage difference, discharge control can be applied to the first energy storage stack. This quickly levels out the excessively high terminal voltage of the energy storage stacks, reduces voltage inconsistencies between stacks, eliminates internal circulating currents caused by voltage differences between branches, balances the operating conditions of each stack, slows down stack degradation, and extends equipment lifespan. Furthermore, relying on the independent branch control characteristics, balancing operations can be completed online without interrupting the normal charging and discharging scheduling of the energy storage system, thus ensuring system operational safety, capacity utilization, and service life.

[0049] In one implementation, the discharge control process of the first fuel cell stack may specifically include: controlling the closing of the bypass switch corresponding to the first fuel cell stack. Then, the process of discharging the first fuel cell stack using the bypass branch corresponding to the first fuel cell stack according to the target discharge current is repeated. The target discharge current is the maximum charge / discharge current of the bypass branch corresponding to the first fuel cell stack, which is 1 / 100 to 1 / 50 of the fuel cell stack's rated operating current. For example, taking a fuel cell stack's rated operating current of 300 A as an example, the target discharge current could be 1 / 50 × 300 = 6 A.

[0050] Correspondingly, the bypass switch corresponding to the first battery stack can be closed by controlling the DC / DC converter. In this way, the first battery stack can be quickly and independently connected to the corresponding bypass branch. With the independent control capability of the DC / DC branch, the battery stack can be individually balanced for charging and discharging without disconnecting the main circuit of the entire vanadium redox flow battery system. This does not affect the normal external energy storage operation of other battery stacks, can accurately isolate individual stacks with abnormal voltage differences to complete voltage leveling, eliminate voltage difference circulating current between battery stacks, and avoid scheduling interruptions caused by system shutdown. This improves the system's balancing flexibility and operational continuity, and can also prevent overcharging and under-discharging damage to high-voltage differential battery stacks, ensuring the capacity utilization and service life of the entire energy storage system.

[0051] S205, determine whether the difference between the voltage value of the first stack and the average voltage value after discharge is less than the second preset voltage difference value.

[0052] Specifically, after discharging the first fuel cell stack, it can be determined whether the difference between the voltage value of the first fuel cell stack after discharge and the average voltage value is less than a second preset voltage difference. The second preset voltage difference is less than the first preset voltage difference. This second preset voltage difference can be preset according to actual conditions, as long as it is less than the first preset voltage difference; the specific value is not limited.

[0053] In some embodiments, if the difference between the voltage value of the first battery stack after discharge and the average voltage value is less than a second preset voltage difference, it indicates that the equalization discharge operation for the first battery stack has achieved its equalization target. Therefore, step S206 can be executed to stop the discharge control of the first battery stack.

[0054] In other embodiments, if the difference between the voltage value of the first stack and the average voltage value after discharge is greater than or equal to a second preset voltage difference, it indicates that the voltage difference between the first stack and other stacks is still large. Therefore, it is necessary to continue executing step S204 to continue discharging control of the first stack, thereby ensuring that the voltage difference between each stack meets the operational balance requirements.

[0055] S206, Stop the discharge control of the first fuel cell stack.

[0056] Specifically, once it is determined that the difference between the voltage value of the first battery stack and the average voltage value after the above discharge is less than the second preset voltage difference, the discharge control of the first battery stack can be stopped. In this way, the termination time of equalization discharge can be precisely controlled, ensuring that the voltage deviation between each battery stack is controlled within a safe and reasonable range, eliminating circulating current and charge / discharge capacity loss, and avoiding problems such as undervoltage and vanadium ion valence state imbalance caused by over-discharging the first battery stack. This reduces unnecessary equalization energy consumption, keeps each battery stack in a uniform and stable operating condition, and reduces battery stack losses and extends the service life of the entire battery system while ensuring the system's equalization effect, operational safety, and capacity utilization.

[0057] In one implementation, the discharge control of the first energy storage stack can be stopped by controlling the bypass switch corresponding to the first energy storage stack to open. Specifically, the bypass switch corresponding to the first energy storage stack is opened via a DC / DC converter. This quickly disconnects the electrical connection between the first energy storage stack and the equalization branch, promptly ending the equalization discharge process for that stack, accurately maintaining the voltage deviation of the single stack within a reasonable range, and avoiding undervoltage and vanadium electrolyte valence imbalance caused by continuous discharge. Simultaneously, this disconnection operation only affects the target energy storage stack branch and does not interfere with the normal charging and discharging operation of other energy storage stacks. The equalization process switching can be completed without shutting down the entire system, reducing additional energy consumption during the equalization process and ensuring the stable and continuous operation of the entire energy storage system.

[0058] The above section introduced how the vanadium redox flow battery management system (VRB) controls the discharge of the stack corresponding to the highest voltage value within the VRB system when faced with a significant difference between the highest and average voltage values, thereby ensuring that the voltage of each stack reaches a balanced state. The following section will further describe how the VRB system controls the charging of the stack corresponding to the lowest voltage value within the VRB system when faced with a significant difference between the average and lowest voltage values, thereby ensuring that the voltage of each stack reaches a balanced state.

[0059] Specifically, this embodiment provides another method for stack balancing control in a full vanadium redox flow battery system, such as... Figure 3 As shown, the method includes: S301, in response to the vanadium redox flow battery system being in a charging state, acquires the voltage values ​​of each stack in the vanadium redox flow battery system.

[0060] It should be noted that this step is related to Figure 2 Step S201 is similar and will not be repeated here.

[0061] S302, the stack with the lowest voltage value in the all-vanadium redox flow battery system is determined as the second stack.

[0062] Specifically, after collecting the voltage values ​​of all stacks in the vanadium redox flow battery system, the stack with the lowest voltage value in the vanadium redox flow battery system can be identified as the second stack.

[0063] In some cases, the individual stacks within a vanadium redox flow battery system can be ordered according to their voltage levels. The stack that appears last in the order can then be designated as the second stack.

[0064] S303, determine whether the difference between the average voltage value and the voltage value of the second stack is greater than the first preset voltage difference value.

[0065] Specifically, after determining the second battery stack, it can be determined whether the difference between the average voltage value and the voltage value of the second battery stack is greater than a first preset voltage difference. If the difference between the average voltage value and the voltage value of the second battery stack is greater than the first preset voltage difference, it indicates that the voltage of the second battery stack is low. Therefore, step S304 needs to be executed to increase the voltage value of the second battery stack. If the difference between the average voltage value and the voltage value of the second battery stack is less than or equal to the first preset voltage difference, it indicates that the voltage differences between the battery stacks are balanced, meaning that there will be no situation where the vanadium redox flow battery system cannot function properly due to excessively small voltage differences. Therefore, charging control of the second battery stack can be omitted, and the process can directly return to step S301 to continue monitoring for small voltage differences between battery stacks.

[0066] S304 controls the charging of the second fuel cell stack.

[0067] Specifically, after determining that the difference between the average voltage value and the voltage value of the second stack is greater than the first preset voltage difference, charging control can be applied to the second stack. This raises the potential of the second stack, which has a low voltage, reduces the voltage deviation between this stack and the other stacks, eliminates internal circulating currents caused by voltage differences in the series-connected branches of multiple stacks, prevents the low-voltage stack from reaching the discharge cutoff voltage prematurely during the discharge phase, thus preventing the entire battery cluster from failing to fully release its capacity, and prevents long-term undervoltage operation of the second stack from causing vanadium ion valence imbalance and electrode performance degradation. This also ensures that the voltages of all stacks are consistent, unifies the charging and discharging conditions of each stack, improves the overall capacity utilization of the energy storage system, and extends the service life of the entire vanadium redox flow battery system.

[0068] In one implementation, the charging control process of the second fuel cell stack may specifically include: controlling the closing of the bypass switch corresponding to the second fuel cell stack. Then, the charging control of the second fuel cell stack is repeatedly performed using the bypass branch corresponding to the second fuel cell stack according to the target discharge current. The target discharge current is the maximum charge / discharge current of the bypass branch corresponding to the first fuel cell stack, which is 1 / 100 to 1 / 50 of the fuel cell stack's rated operating current. For example, taking a fuel cell stack's rated operating current of 300 A as an example, the target discharge current could be 1 / 50 × 300 = 6 A.

[0069] Correspondingly, the bypass switch corresponding to the second stack can be closed via a DC / DC converter. This allows the second stack to be quickly and independently connected to its corresponding bypass branch. Utilizing the independent control capability of the DC / DC branch, this stack can be subjected to separate equalization charging and discharging operations without disconnecting the main circuit of the entire vanadium redox flow battery system. This does not affect the normal external energy storage operation of other stacks, accurately isolates individual stacks with abnormal voltage differences to achieve voltage leveling, eliminates inter-stack voltage differential circulating currents, and avoids scheduling interruptions caused by system shutdowns. This improves the system's equalization flexibility and operational continuity, and also prevents overcharging and under-discharging damage to high-voltage differential stacks, ensuring the capacity utilization and lifespan of the entire energy storage system.

[0070] S305, determine whether the difference between the average voltage value and the voltage value of the second stack after charging is less than a second preset voltage difference value.

[0071] Specifically, after controlling the charging of the second battery stack, it can be determined whether the difference between the average voltage value and the voltage value of the second battery stack after charging is less than a second preset voltage difference. The second preset voltage difference is less than a first preset voltage difference.

[0072] In some embodiments, if the difference between the average voltage value and the voltage value of the second battery stack after charging is less than a second preset voltage difference, it indicates that the equalization charging operation for the second battery stack has achieved its equalization target. Therefore, step S306 can be executed to stop the charging control of the second battery stack.

[0073] In other embodiments, if the difference between the average voltage value and the voltage value of the second stack after charging is greater than or equal to a second preset voltage difference, it indicates that the voltage difference between the second stack and other stacks is still small. Therefore, it is necessary to continue executing step S304 to continue charging control of the second stack, thereby ensuring that the voltage difference between each stack meets the operational balancing requirements.

[0074] S306, Stop charging control of the second fuel cell stack.

[0075] Specifically, once the difference between the average voltage value and the voltage value of the second battery stack after charging is determined to be less than a second preset voltage difference, the charging control of the second battery stack can be stopped. This allows for precise control of the termination timing of equalization charging, ensuring that the voltage deviation between each battery stack is kept within a safe and reasonable range, eliminating circulating current and charge / discharge capacity loss, while also avoiding overvoltage and vanadium ion valence imbalance caused by overcharging of the second battery stack. This reduces unnecessary equalization energy consumption, maintains uniform and stable operating conditions for each battery stack, and while ensuring system equalization effectiveness, operational safety, and capacity utilization, reduces battery stack losses and extends the lifespan of the entire battery system.

[0076] In one implementation, the charging control of the second energy storage stack can be stopped by controlling the bypass switch corresponding to the second energy storage stack to open. Specifically, the bypass switch corresponding to the second energy storage stack is opened via a DC / DC converter. This quickly disconnects the electrical connection between the second energy storage stack and the equalization branch, promptly ending the equalization charging process for that stack, accurately maintaining the voltage deviation of the single stack within a reasonable range, and avoiding overvoltage and vanadium electrolyte valence imbalance caused by continuous charging. Simultaneously, this disconnection operation only applies to the target energy storage stack branch and does not interfere with the normal charging and discharging operation of other energy storage stacks. The equalization process can be switched without shutting down the entire system, reducing additional energy consumption during the equalization process and ensuring the stable and continuous operation of the entire energy storage system.

[0077] Furthermore, as Figure 2 In a specific implementation of the method, this application provides a stack balancing control device for an all-vanadium redox flow battery system, such as... Figure 4 As shown, the device includes: a voltage acquisition module 401, a fuel cell stack determination module 402, and an electric propulsion control module 403.

[0078] The voltage acquisition module 401 is used to acquire the voltage values ​​of each stack in the vanadium redox flow battery system in response to the vanadium redox flow battery system being in a charging state. The stack determination module 402 is used to determine the stack with the highest voltage value in the vanadium redox flow battery system as the first stack. The electric propulsion control module 403 is used to repeatedly perform discharge control on the first electric stack when the difference between the voltage value of the first electric stack and the average voltage value is greater than a first preset voltage difference, until the difference between the voltage value of the first electric stack and the average voltage value after discharge is less than a second preset voltage difference, and then stop the discharge control of the first electric stack; wherein, the second preset voltage difference is less than the first preset voltage difference.

[0079] Furthermore, in one possible implementation of this embodiment, such as Figure 4 As shown, the electric propulsion control module 403 is also used to control the bypass switch corresponding to the first electric stack to close when the difference between the voltage value of the first electric stack and the average voltage value is greater than a first preset voltage difference. Repeatedly discharge the first battery stack using the bypass branch corresponding to the first battery stack according to the target discharge current until the difference between the voltage value of the first battery stack and the average voltage value after discharge is less than the second preset voltage difference. The bypass switch corresponding to the first fuel cell stack is disconnected to stop the discharge control of the first fuel cell stack.

[0080] Furthermore, in one possible implementation of this embodiment, such as Figure 4As shown, the electric propulsion control module 403 is also used to control the bypass switch corresponding to the first electric stack to close through a bidirectional DC-DC converter when the difference between the voltage value of the first electric stack and the average voltage value is greater than a first preset voltage difference. The bypass switch corresponding to the first fuel cell stack is disconnected by using a bidirectional DC-DC converter.

[0081] Furthermore, in one possible implementation of this embodiment, such as Figure 4 As shown, the stack determination module 402 is also used to determine the stack with the lowest voltage value in the vanadium redox flow battery system as the second stack. The electric propulsion control module 403 is also used to repeatedly perform charging control on the second electric stack when the difference between the average voltage value and the voltage value of the second electric stack is greater than the first preset voltage difference, until the average voltage value and the voltage value of the charged second electric stack are less than the second preset voltage difference, and then stop the charging control of the second electric stack.

[0082] Furthermore, in one possible implementation of this embodiment, such as Figure 4 As shown, the electric propulsion control module 403 is also used to control the bypass switch corresponding to the second electric stack to close when the difference between the average voltage value and the voltage value of the second electric stack is greater than the first preset voltage difference. Repeatedly execute the bypass branch corresponding to the second battery stack, and charge the second battery stack according to the target discharge current until the average voltage value and the voltage value of the second battery stack after charging are less than the second preset voltage difference. The bypass switch corresponding to the second fuel cell stack is disconnected to stop the charging control of the second fuel cell stack.

[0083] Furthermore, in one possible implementation of this embodiment, such as Figure 5 As shown, the stack balancing control device in the all-vanadium redox flow battery system also includes a protection control module 404.

[0084] The protection control module 404 is used to perform an audible and visual alarm operation when the voltage value of any stack in the vanadium redox flow battery system is within a first preset voltage range and the cumulative time of the voltage value within the first preset voltage range reaches a preset cumulative time; wherein, the lower limit value corresponding to the first preset voltage range is the first preset voltage value, and the upper limit value corresponding to the first preset voltage range is the second preset voltage value. If the voltage value of any stack in the vanadium redox flow battery system is within the second preset voltage range, and the cumulative time the voltage value is within the second preset voltage range reaches a preset cumulative time, the vanadium redox flow battery system is controlled to stop charging; wherein, the lower limit value corresponding to the second preset voltage range is the second preset voltage value, and the upper limit value corresponding to the second preset voltage range is the third preset voltage value. If, within the vanadium redox flow battery system, the voltage value of any stack exceeds a third preset voltage value, and the cumulative duration of the voltage value exceeding the third preset voltage value reaches a preset cumulative duration, an emergency protection operation is performed on the vanadium redox flow battery system.

[0085] Furthermore, in one possible implementation of this embodiment, such as Figure 5 As shown, the protection control module 404 is also used to determine the difference between the highest voltage value and the lowest voltage value in the vanadium redox flow battery system as the target stack pressure difference; When the target stack pressure difference is within the first preset stack pressure difference range, an audible and visual alarm is executed; wherein, the lower limit value corresponding to the first preset stack pressure difference range is the first preset stack pressure difference, and the upper limit value corresponding to the first preset stack pressure difference range is the second preset stack pressure difference. When the target stack pressure difference is within the second preset stack pressure difference range, the vanadium redox flow battery system is controlled to stop charging; wherein, the lower limit of the second preset stack pressure difference range is the second preset stack pressure difference, and the upper limit of the second preset stack pressure difference range is the third preset stack pressure difference. If the target stack pressure difference is greater than the third preset stack pressure difference, an emergency protection operation is performed on the vanadium redox flow battery system.

[0086] It should be noted that other corresponding descriptions of the functional units involved in the stack balancing control device of the all-vanadium redox flow battery system provided in this application embodiment can be found by referring to... Figures 2 to 3 The corresponding descriptions in the method will not be repeated here.

[0087] This application also provides a computer device, specifically a personal computer, server, network device, etc. The computer device includes a bus, processor, memory, and communication interface, and may also include input / output interfaces and a display device. The processor of the computer device provides computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The database of the computer device stores location information. The network interface of the computer device is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements the steps in the various method embodiments.

[0088] Those skilled in the art will understand that the structure of the computer device described above is only a partial structure related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. A specific computer device may include more or fewer components, or combine certain components, or have different component arrangements.

[0089] In one embodiment, a computer-readable storage medium is provided, which may be non-volatile or volatile, having stored thereon a computer program that, when executed by a processor, implements the steps in the above method embodiments.

[0090] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above method embodiments.

[0091] It should be noted that the user personal information involved in the embodiments of this application is all authorized (with the knowledge and consent) by the relevant parties or fully authorized by all parties, and the executing entity can obtain it through various legal and compliant means. The collection, storage, use, processing, transmission, provision, and disclosure of the information, data, and signals involved all comply with the relevant laws and regulations of the relevant countries and regions, and do not violate public order and good morals. It should be noted that if any software tools or components other than those of this company appear in the embodiments of this application, they are merely illustrative examples and do not represent actual use.

[0092] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, graphics processors, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0093] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0094] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for stack equalization control in a vanadium redox flow battery system, characterized in that, include: In response to the vanadium redox flow battery system being in a charging state, the voltage values ​​of each stack in the vanadium redox flow battery system are obtained; The stack with the highest voltage value in the vanadium redox flow battery system is defined as the first stack. If the difference between the voltage value of the first fuel cell stack and the average voltage value is greater than a first preset voltage difference, the discharge control of the first fuel cell stack is repeatedly executed until the difference between the voltage value of the first fuel cell stack and the average voltage value after discharge is less than a second preset voltage difference, and the discharge control of the first fuel cell stack is stopped; wherein, the second preset voltage difference is less than the first preset voltage difference.

2. The method according to claim 1, characterized in that, The step of repeatedly performing discharge control on the first battery stack when the difference between the voltage value and the average voltage value of the first battery stack is greater than a first preset voltage difference, until the difference between the voltage value and the average voltage value of the first battery stack after discharge is less than a second preset voltage difference, and then stopping the discharge control of the first battery stack, includes: If the difference between the voltage value of the first fuel cell stack and the average voltage value is greater than a first preset voltage difference, the bypass switch corresponding to the first fuel cell stack is controlled to close. Repeatedly discharge the first battery stack using the bypass branch corresponding to the first battery stack according to the target discharge current until the difference between the voltage value of the first battery stack and the average voltage value after discharge is less than the second preset voltage difference. The bypass switch corresponding to the first fuel cell stack is disconnected to stop the discharge control of the first fuel cell stack.

3. The method according to claim 2, characterized in that, When the difference between the voltage value of the first fuel cell stack and the average voltage value is greater than a first preset voltage difference, controlling the bypass switch corresponding to the first fuel cell stack to close includes: If the difference between the voltage value of the first fuel cell stack and the average voltage value is greater than the first preset voltage difference, the bypass switch corresponding to the first fuel cell stack is controlled to close through the bidirectional DC-DC converter. The control of the bypass switch corresponding to the first fuel cell stack to disconnect includes: The bypass switch corresponding to the first fuel cell stack is disconnected by controlling the bidirectional DC-DC converter.

4. The method according to any one of claims 1-3, characterized in that, After obtaining the voltage values ​​of each stack in the vanadium redox flow battery system, the method further includes: The stack with the lowest voltage value in the vanadium redox flow battery system is designated as the second stack. If the difference between the average voltage value and the voltage value of the second battery stack is greater than a first preset voltage difference, the charging control of the second battery stack is repeated until the average voltage value and the voltage value of the charged second battery stack are less than a second preset voltage difference, at which point the charging control of the second battery stack is stopped.

5. The method according to claim 4, characterized in that, When the difference between the average voltage value and the voltage value of the second battery stack is greater than a first preset voltage difference, the charging control of the second battery stack is repeatedly executed until the average voltage value and the voltage value of the charged second battery stack are less than the second preset voltage difference, and the charging control of the second battery stack is stopped, including: If the difference between the average voltage value and the voltage value of the second fuel cell stack is greater than a first preset voltage difference, the bypass switch corresponding to the second fuel cell stack is controlled to close. Repeatedly execute the bypass branch corresponding to the second stack, and charge the second stack according to the target discharge current until the average voltage value and the voltage value of the charged second stack are less than the second preset voltage difference. The bypass switch corresponding to the second fuel cell stack is disconnected to stop the charging control of the second fuel cell stack.

6. The method according to any one of claims 1-3, characterized in that, After obtaining the voltage values ​​of each stack in the vanadium redox flow battery system, the method further includes: If, within the vanadium redox flow battery system, the voltage value of any stack is within a first preset voltage range, and the cumulative duration of the voltage value within the first preset voltage range reaches a preset cumulative duration, an audible and visual alarm operation is executed; wherein, the lower limit value corresponding to the first preset voltage range is the first preset voltage value, and the upper limit value corresponding to the first preset voltage range is the second preset voltage value. If the voltage value of any stack in the vanadium redox flow battery system is within a second preset voltage range, and the cumulative duration of the voltage value within the second preset voltage range reaches a preset cumulative duration, the vanadium redox flow battery system is controlled to stop charging; wherein, the lower limit value corresponding to the second preset voltage range is the second preset voltage value, and the upper limit value corresponding to the second preset voltage range is the third preset voltage value. If, within the vanadium redox flow battery system, the voltage value of any stack exceeds a third preset voltage value, and the cumulative duration of the voltage value exceeding the third preset voltage value reaches a preset cumulative duration, an emergency protection operation is performed on the vanadium redox flow battery system.

7. The method according to any one of claims 1-3, characterized in that, After obtaining the voltage values ​​of each stack in the vanadium redox flow battery system, the method further includes: The difference between the highest and lowest voltage values ​​in the vanadium redox flow battery system is defined as the target stack pressure difference. When the target stack pressure difference is within the first preset stack pressure difference range, an audible and visual alarm is executed; wherein, the lower limit value corresponding to the first preset stack pressure difference range is the first preset stack pressure difference, and the upper limit value corresponding to the first preset stack pressure difference range is the second preset stack pressure difference. When the target stack pressure difference is within the second preset stack pressure difference range, the vanadium redox flow battery system is controlled to stop charging; wherein, the lower limit value corresponding to the second preset stack pressure difference range is the second preset stack pressure difference, and the upper limit value corresponding to the second preset stack pressure difference range is the third preset stack pressure difference. If the target stack pressure difference is greater than the third preset stack pressure difference, an emergency protection operation is performed on the vanadium redox flow battery system.

8. A stack balancing control device for an all-vanadium redox flow battery system, characterized in that, include: The voltage acquisition module is used to acquire the voltage values ​​of each stack in the vanadium redox flow battery system in response to the vanadium redox flow battery system being in a charging state. The stack determination module is used to determine the stack with the highest voltage value in the vanadium redox flow battery system as the first stack. The electric propulsion control module is used to repeatedly perform discharge control on the first electric stack when the difference between the voltage value and the average voltage value of the first electric stack is greater than a first preset voltage difference, until the difference between the voltage value and the average voltage value of the first electric stack after discharge is less than or equal to a second preset voltage difference, and then stop the discharge control of the first electric stack; wherein, the second preset voltage difference is less than the first preset voltage difference.

9. A storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method of any one of claims 1 to 7.

10. A computer device, comprising a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method of any one of claims 1 to 7.

Images