A flow battery temperature control system and energy-saving method

Abstract

This invention discloses a flow battery temperature control system and energy-saving method, comprising several structurally identical flow battery energy storage cells distributedly connected to a centralized temperature management module; the bottom ends of the positive electrode stack and the negative electrode stack are respectively connected to the bottom sidewalls of the positive electrode storage tank and the negative electrode storage tank via connecting pipeline structures; the connecting pipeline structure includes a secondary distribution system, a parallel branch module, a filter, a circulation pump, and a butterfly valve connected sequentially via pipelines; the parallel branch module includes a main circulation pipeline for use in non-cold operation mode and a temperature control branch for use in cold operation mode; the centralized temperature management module controls the opening and closing of the main circulation pipeline or the temperature control branch based on the real-time electrolyte temperature collected by a temperature sensor, thereby optimizing system energy consumption. This invention solves the problem that existing technologies struggle to achieve low static energy consumption, low pollution risk, and high system integration while ensuring efficient heat dissipation.

Description

Technical Field

[0001] This invention relates to the field of vanadium redox flow battery energy storage technology, and in particular to a flow battery temperature control system and energy-saving method. Background Technology

[0002] During the charging and discharging process of a flow battery, heat is generated due to electrochemical reactions, internal resistance heating, and pump consumption, leading to an increase in electrolyte temperature. Excessively high operating temperatures accelerate electrolyte decomposition and membrane material aging, affecting battery performance and lifespan. Conversely, excessively low temperatures may cause electrolyte crystallization and increased viscosity, impacting system efficiency. Therefore, the temperature control system is a crucial component for the stable operation of a flow battery energy storage system.

[0003] Currently, common temperature control solutions for flow batteries can be mainly divided into two categories: (1) Centralized cooling system: A large plate or shell-and-tube heat exchanger is installed on the main outlet pipeline of the battery stack to cool all the electrolyte through an external cold source (such as a chiller). This system has a simple structure but significant drawbacks. First, regardless of whether the battery needs cooling, as long as the pump is running, it must overcome the pipeline pressure drop caused by the heat exchanger, resulting in continuous additional pump consumption. Second, the refrigeration system (such as compressors and cooling towers) may still operate inefficiently or need to be frequently started and stopped when the battery heat generation is not large, resulting in energy waste. Third, the electrolyte is in contact with the metal heat exchanger for a long time and over a large area, which poses a risk of metal ion dissolution and contamination of the electrolyte, especially for electrolytes containing active substances or additives, which limits the use of metal heat exchangers. (2) Decentralized cooling system: An independent small heat exchanger is installed at each group of battery stacks or each module. Although this scheme can shorten the heat exchange flow path, the system is complex, costly, and has low integration, and it also has the problem of flow resistance loss during non-cooling periods.

[0004] As flow batteries advance towards higher power densities, the heat generated per unit volume increases significantly, placing higher demands on the efficiency, energy consumption, and reliability of temperature control systems. More precise temperature control leads to higher energy consumption, which accounts for a large proportion of total energy consumption; therefore, bypassing methods should be used to minimize heat exchange energy consumption. Current technologies struggle to simultaneously achieve low static energy consumption, low pollution risk, and high system integration while ensuring efficient heat dissipation. Summary of the Invention

[0005] This invention provides a flow battery temperature control system and energy-saving method to overcome the above-mentioned technical problems.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: A flow battery temperature control system includes several structurally identical flow battery energy storage cells that are distributedly connected to a centralized temperature management module. The flow battery energy storage cell includes a positive electrode stack and a negative electrode stack symmetrically arranged on both sides of a proton exchange membrane. The top of the positive electrode stack is connected to the top of the positive electrode storage tank, and the top of the negative electrode stack is connected to the top of the negative electrode storage tank. The bottom of the positive electrode stack and the bottom of the negative electrode stack are respectively connected to the bottom sidewall of the positive electrode storage tank and the bottom sidewall of the negative electrode storage tank through connecting pipeline structures. The connecting pipeline structure includes a secondary distribution system, a parallel branch module, a filter, a circulating pump, and a butterfly valve connected sequentially through pipelines; and a temperature sensor is installed on the pipeline between the secondary distribution system and the parallel branch module. The parallel branch module includes a main circulation pipeline for activation in non-cold operation mode and a temperature control branch for activation in refrigeration operation mode. The output terminal of the centralized temperature management module is electrically connected to the parallel branch module, and the input terminal of the centralized temperature management module is connected to the output terminal of the temperature sensor. The centralized temperature management module is used to obtain the real-time electrolyte temperature collected by the temperature sensor after the electrolyte in the positive or negative electrode storage tank flows through the butterfly valve, circulation pump, filter and parallel branch module in sequence, and to control the opening and closing of the main circulation pipeline or temperature control branch according to the real-time electrolyte temperature.

[0007] Furthermore, the main circulation pipeline is the main connection pipeline equipped with a second solenoid valve.

[0008] Furthermore, the temperature control branch is equipped with a heat exchanger, one end of which is connected to one end of a pipeline equipped with a temperature sensor via a branch connection pipeline, and the other end of which is connected to one end of a filter via a branch connection pipeline; a first solenoid valve is provided on the pipeline between the heat exchanger and the filter.

[0009] Furthermore, the pipelines connecting the input and output ends of the circulating pump are respectively equipped with a pump inlet expansion joint and a pump outlet expansion joint.

[0010] Furthermore, the secondary distribution system includes several stack inlet bellows connected in parallel with the positive or negative electrode stack. One end of the stack inlet bellows is connected to the secondary distribution buffer chamber, and the secondary distribution buffer chamber is connected to the inlet of the corresponding positive or negative electrode stack through at least two stack inlet bellows. Meanwhile, the other end of the secondary distribution buffer chamber is connected to a ball valve and a flow sensor in sequence through pipelines.

[0011] An energy-saving method for a flow battery temperature control system, specifically including the following steps: S1: The pre-installed battery management system (BMS) collects data from temperature sensors to monitor the current electrolyte temperature T in the corresponding pipeline in real time. S2: Set the temperature hysteresis range and determine the relationship between the current electrolyte temperature T and the temperature hysteresis range. If the current electrolyte temperature T is lower than the lower limit of the optimal operating temperature of the temperature hysteresis range, then execute S3; if the current electrolyte temperature T is within the temperature hysteresis range, then execute S4; if the current electrolyte temperature T is higher than the upper limit of the optimal operating temperature of the temperature hysteresis range, then execute S5. S3: The centralized temperature management module controls the flow battery temperature control system to be in non-cooling operation mode, that is, controls the first solenoid valve on the temperature control branch to close and the second solenoid valve on the main circulation pipeline to open, and maintains the electrolyte temperature stability by activating the pre-installed heat preservation device on the outside of the positive or negative electrode storage tank. S4: Maintain the current pipeline on / off status; S5: The centralized temperature management module controls the flow battery temperature control system to be in cooling operation mode. This means controlling the opening of the first solenoid valve on the temperature control branch and simultaneously closing the second solenoid valve on the main circulation pipeline, or adjusting the opening ratio between the second and first solenoid valves, thereby optimizing the pumping energy consumption of the flow battery temperature control.

[0012] Furthermore, the average pumping consumption corresponding to the optimization of pumping energy consumption for flow battery temperature control in S5 is:

[0013] In the formula: This indicates the percentage of runtime during which the system requires cooling. These represent the average pump consumption, the pump consumption of the corresponding main circulation pipeline, and the pump consumption of the temperature control branch where the heat exchanger is located, respectively.

[0014] Furthermore, the method for adjusting the opening ratio of the second solenoid valve and the first solenoid valve in S5 is as follows: S51: Obtain the temperature deviation between the current electrolyte temperature T and the set target temperature, and obtain the required cooling demand coefficient through a proportional-integral-derivative controller. for:

[0015]

[0016]

[0017] In the formula: Indicates temperature deviation; Indicates the current electrolyte temperature; This indicates that the target temperature is set and is a temperature value within the temperature hysteresis interval; Indicates intermediate variables; Represents the controller coefficients of a proportional-integral-derivative controller; Indicates used to Functions restricted to the interval [0,1]; Indicates a time parameter; Indicates the cooling demand coefficient; S52: Define the valve opening degree of the first solenoid valve and the second solenoid valve as... According to the cooling demand coefficient Construct a system for solving valve opening. The collaborative solution equations are used to obtain the corresponding cooling demand coefficients. Valve opening ; And the expression for the collaborative solution equation is:

[0018] In the formula: Indicates the total system traffic; This indicates the flow rate when the heat exchanger is operating at full capacity. This indicates the flow rate of the main circulation pipeline; Indicates valve opening degree and flow coefficient The calibration function; This indicates the voltage drop in the temperature control branch; This indicates the pressure drop in the main circulation pipeline; This indicates the pressure drop used to compensate for pipeline pressure.

[0019] This invention provides a flow battery temperature control system and energy-saving method, with the following beneficial effects: 1. Improved System Reliability and Integration: The system has a simple structure, with only one temperature control branch connected in parallel on the main circulation pipeline. This eliminates the need for independent heat exchange units for each module, reducing pipeline complexity and potential leakage points, and improving system integration and reliability. Simultaneously, the centralized temperature management module enables rapid intelligent control mode switching, allowing for precise adjustment of cooling based on the actual heat load of the battery, preventing overheating or undercooling of the battery stack, and enhancing the overall stability and safety of the system.

[0020] 2. Significantly Reduced Total System Energy Consumption: During extended periods when cooling is not required, the system shuts down the refrigeration equipment and cooling branches, eliminating energy consumption in the refrigeration system and pressure losses through the heat exchanger. It is estimated that this can reduce system auxiliary power consumption (pump consumption + refrigeration) by 30%-60% (depending on operating conditions and climate). During periods requiring cooling, the centralized temperature management module intelligently controls mode switching, avoiding inefficient operation of the cold source equipment and further optimizing refrigeration energy consumption.

[0021] 3. Directly reduces the operating cost of energy storage systems through energy conservation and consumption reduction: This invention can extend the replacement cycle of electrolyte and heat exchanger, reducing maintenance costs. It is especially suitable for large-scale flow battery energy storage power stations with high power density, large heat generation, and sensitivity to energy consumption and lifespan, and has good prospects for industrial application. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of a flow battery temperature control system according to the present invention; Figure 2 This is a flowchart of an energy-saving method for a flow battery temperature control system in this embodiment.

[0024] In the diagram: 1. Centralized temperature management module; 2. Cable; 3. Flow battery energy storage cell; 4. Positive electrode storage tank; 5. Butterfly valve; 6. Pump inlet expansion joint; 7. Pump outlet expansion joint; 8. First solenoid valve; 9. Second solenoid valve; 10. Flow sensor; 11. Ball valve; 12. Secondary distribution system buffer chamber; 13. Circulation pump; 14. Negative electrode storage tank; 15. Heat exchanger; 16. Positive electrode stack; 17. Proton exchange membrane; 18. Negative electrode stack; 19. Branch connection pipeline; 20. Main connection pipeline; 21. Temperature sensor; 22. Filter; 23. Stack inlet bellows. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] This embodiment provides a flow battery temperature control system, such as Figure 1As shown, it includes a centralized temperature management module 1 and several flow battery energy storage units 3 with the same structure that are distributedly connected to the centralized temperature management module 1; the flow battery energy storage unit 3 includes a positive electrode stack 16 and a negative electrode stack 18 symmetrically arranged on both sides of the proton exchange membrane 17. The top of the positive electrode stack 16 is connected to the top of the positive electrode storage tank 4, and the top of the negative electrode stack 18 is connected to the top of the negative electrode storage tank 14. The bottom ends of the positive electrode stack 16 and the bottom ends of the negative electrode stack 18 are respectively connected to the bottom side wall of the positive electrode storage tank 4 and the bottom side wall of the negative electrode storage tank 14 through a connecting pipeline structure. The connecting pipeline structure includes a secondary distribution system, a parallel branch module, a filter 22, a circulation pump 13, and a butterfly valve 5 connected in sequence through pipelines; and a temperature sensor 21 is provided on the pipeline between the secondary distribution system and the parallel branch module; specifically, in this embodiment, a temperature sensor 21 is set before the electrolyte inlet of the battery stack to monitor the electrolyte temperature in real time and transmit it to the centralized temperature management module 1 through a pre-installed cable 2; Specifically, the secondary distribution system includes several stack inlet bellows 23 connected in parallel with the positive electrode stack 16 or the negative electrode stack 18. One end of each stack inlet bellows 23 is connected to a secondary distribution buffer chamber 12, and the secondary distribution buffer chamber 12 is connected to the inlet of the corresponding positive electrode stack 16 or negative electrode stack 18 via at least two stack inlet bellows 23. The other end of the secondary distribution buffer chamber 12 is connected sequentially to a ball valve 11 and a flow sensor 10 via pipelines. For example, in this embodiment, the stack inlet bellows 23 are coded as 1,2,3,4,5,6,7,......,m-1,m; the stack inlet bellows 23 are divided into several bellows pairs {1,2},{3,4},{5,6},......,{m-1,m}, and the output end of each bellows pair corresponds to a secondary distribution buffer chamber 12. The parallel branch module includes a main circulation pipeline for activation in non-cold operation mode and a temperature control branch for activation in cold operation mode, namely, a temperature control branch is connected in parallel on the main pipeline between the outlet of circulation pump 13 and the inlet of battery stack. Specifically, the main circulation pipeline is the main connecting pipeline 20 equipped with a second solenoid valve 9. In this embodiment, the second solenoid valve 9 is installed in parallel with the temperature control branch on the main circulation pipeline and serves as a bypass valve. The temperature control branch is equipped with a heat exchanger 15. One end of the heat exchanger 15 is connected to one end of the pipeline equipped with a temperature sensor 21 through a branch connecting pipeline 19, and the other end of the heat exchanger 15 is connected to one end of the filter 22 through a branch connecting pipeline 19. A first solenoid valve 8 is installed on the pipeline between the heat exchanger 15 and the filter 22. In this embodiment, the heat exchanger is preferably a titanium tube heat exchanger 15 with excellent corrosion resistance. In this embodiment, considering the traditional flow battery temperature control system, the electrolyte must flow through the heat exchanger 15 throughout the entire process, regardless of whether cooling is required. The heat exchanger 15 and its connecting pipelines constitute a fixed and unavoidable flow resistance element, leading to continuous and unnecessary pumping energy loss. Therefore, this embodiment introduces a parallel temperature control branch with heat exchanger 15 that bypasses the main circulation pipeline, and uses a centralized temperature management module 1 to achieve intelligent valve control of the solenoid valve, realizing "on-demand loading / unloading" of this fixed flow resistance.

[0027] The total flow resistance of a traditional fixed flow path system is always:

[0028] In the formula: This indicates the pressure loss along the pipeline; Indicates the pressure loss of the fuel cell stack; This indicates the pressure loss caused by heat exchanger 15 and its branch valves and fittings; The theoretical power consumption of circulating pump 13 Proportional to total flow resistance With flow rate Q, regardless of whether cooling is required, The item always exists, which in turn leads to static pump consumption; In this embodiment, the system bypass mode, i.e., when the main circulation pipeline bypass valve is open and no cooling is required, results in a total system flow resistance of [missing information]. Always:

[0029] At this point, the heat exchanger with high flow resistance has 15 branches. Completely cut off, the electrolyte flows through the main bypass valve, i.e., the second solenoid valve 9, which has extremely low flow resistance. The design ensures that the flow resistance when the bypass valve is fully open is much lower than that of branch 15 of the heat exchanger, i.e.:

[0030] Therefore, the total flow resistance is:

[0031] Therefore, in bypass mode where cooling is not required, the total system flow resistance in this embodiment is the same as the total flow resistance of a conventional system without heat dissipation piping. .

[0032] The average pump consumption of the system described in this embodiment depends on the ratio of the operating time of the two modes, and the expression for the average pump consumption is as follows:

[0033] In the formula: This indicates the percentage of runtime during which the system requires cooling. These represent the average pump consumption, the pump consumption of the corresponding main circulation pipeline, and the pump consumption of the temperature control branch where heat exchanger 15 is located, respectively.

[0034] This implementation applies to most energy storage application scenarios (such as daily cycles and seasonal changes). It may be less than 50%. Therefore, the system operates in a low-pump-consumption bypass mode most of the time, thus achieving considerable cumulative pump energy savings. The reduced energy consumption due to the bypass flow resistance of the electrolyte and the elimination of the need to turn on the heat exchanger 15 save energy and further reduce losses along the pipeline.

[0035] The output terminal of the centralized temperature management module 1 is electrically connected to the parallel branch module, and the input terminal of the centralized temperature management module 1 is connected to the output terminal of the temperature sensor 21. The centralized temperature management module 1 is used to obtain the real-time electrolyte temperature collected by the temperature sensor 21 after the electrolyte in the positive electrode storage tank 4 or negative electrode storage tank 14 flows through the butterfly valve 5, circulation pump 13, filter 22 and parallel branch module in sequence. Based on the real-time electrolyte temperature, the module controls the opening and closing of the main circulation pipeline or temperature control branch, thereby optimizing the pumping energy consumption of the system.

[0036] In a specific embodiment, the pipelines connecting the input and output ends of the circulating pump 13 are respectively equipped with a pump inlet expansion joint 6 and a pump outlet expansion joint 7. The functions of the pump inlet expansion joint 6 and the pump outlet expansion joint 7 include at least: A. Thermal expansion compensation: When the pump is transporting a high-temperature medium, the metal pipeline will displace due to thermal expansion and contraction. The expansion joint absorbs the displacement through flexible deformation, avoiding rigid connection failure and preventing flange leakage or support damage caused by stress concentration in the pipeline. B. Mechanical vibration isolation: The rubber or metal corrugated structure of the expansion joint can attenuate the impact energy of the instantaneous water hammer pressure and long-term vibration generated when the pump starts and stops, reduce the system stiffness and reduce vibration transmission, and protect the pump and pipeline system.

[0037] An energy-saving method for a flow battery temperature control system, such as Figure 2 As shown, the specific steps include: S1: The temperature sensor 21 is used to monitor the current electrolyte temperature T in the corresponding pipeline in real time through the pre-installed battery management system (BMS). S2: Set the temperature hysteresis range and determine the relationship between the current electrolyte temperature T and the temperature hysteresis range. If the current electrolyte temperature T is lower than the lower limit of the optimal operating temperature of the temperature hysteresis range, then execute S3; if the current electrolyte temperature T is within the temperature hysteresis range, then execute S4; if the current electrolyte temperature T is higher than the upper limit of the optimal operating temperature of the temperature hysteresis range, then execute S5. Specifically, the system is set to have a temperature hysteresis range as follows:

[0038] In the formula: Indicates the upper and lower limits of the optimal operating temperature for the temperature hysteresis range; In this embodiment, to prevent frequent mode switching, the current operating mode is maintained when the temperature is within the hysteresis range. In addition, the system described in this embodiment simultaneously monitors the branch and main pressure p to ensure a smooth switching process and prevent water hammer.

[0039] S3: The centralized temperature management module 1 controls the flow battery temperature control system to operate in a non-cooling mode. This involves closing the first solenoid valve 8 on the temperature control branch and opening the second solenoid valve 9 on the main circulation pipeline. This activates the pre-installed insulation device around the positive or negative electrode storage tank 14 to maintain a stable electrolyte temperature. At this time, all the electrolyte flows through the main circulation pipeline, completely bypassing the heat exchanger. The system does not activate an external cold source, and the electrolyte flow resistance and pump consumption are minimized, achieving "zero static" temperature control standby.

[0040] S4: Maintain the current pipeline on / off status; S5: The centralized temperature management module 1 controls the flow battery temperature control system to operate in a cooling mode. This involves opening the first solenoid valve 8 on the temperature control branch while simultaneously closing the second solenoid valve 9 on the main circulation pipeline, or adjusting the opening ratio between the second solenoid valve 9 and the first solenoid valve 8. This optimizes the pumping energy consumption for the flow battery temperature control. Specifically, when the electrolyte temperature exceeds the set threshold optimal operating temperature upper limit T... high If the battery current I predicts that the heat generation power P will cause the temperature T to exceed the standard, the controller, i.e., the centralized temperature management module 1, opens the first solenoid valve 8 on the temperature control branch, while simultaneously closing or adjusting the second solenoid valve 9 on the main branch. At this time, all or part of the electrolyte is guided to flow through the heat exchanger of the temperature control branch for cooling; the external cold source starts or adjusts its power as needed. By adjusting the opening ratio of the two solenoid valves, precise and continuous control of the coolant flow rate and cooling intensity can be achieved.

[0041] Specifically, in this embodiment, the method for adjusting the opening ratio between the second solenoid valve and the first solenoid valve is as follows: S51: Obtain the temperature deviation between the current electrolyte temperature T and the set target temperature, and obtain the required cooling demand coefficient through a proportional-integral-derivative controller. Its physical meaning is the proportion of the flow rate that needs to pass through the heat exchanger to the total flow rate:

[0042]

[0043]

[0044] In the formula: Indicates temperature deviation; Indicates the current electrolyte temperature; This indicates that the target temperature is set and is a temperature value within the temperature hysteresis interval; Indicates intermediate variables; Represents the controller coefficients of a proportional-integral-derivative controller; Indicates used to Functions restricted to the interval [0,1]; Indicates a time parameter; Indicates the cooling demand coefficient; =0 indicates no cooling required (goal: full bypass). =1 indicates that maximum cooling is required (goal: full flow through the heat exchanger). S52: Define the valve opening degree of the first solenoid valve and the second solenoid valve as... According to the cooling demand coefficient Construct a system for solving valve opening. The collaborative solution equations are used to obtain the corresponding cooling demand coefficients. Valve opening ; Total system flow in this embodiment In the distribution between the main circulation pipeline (opening degree β) and the temperature control branch (opening degree α), the opening degrees α (first solenoid valve) and β (second solenoid valve) of the two valves need to be calculated collaboratively to satisfy the flow distribution coefficient k and maintain system pressure stability. Based on flow balance and valve characteristics, the expression of the collaborative calculation equation is as follows:

[0045] In the formula: Indicates the total system traffic; This indicates the flow rate when the heat exchanger is operating at full capacity. This indicates the flow rate of the main circulation pipeline; Indicates valve opening degree and flow coefficient The calibration function; This indicates the voltage drop in the temperature control branch; This indicates the pressure drop in the main circulation pipeline; This indicates the pressure drop used to compensate for pipeline pressure.

[0046] Based on the thermodynamic characteristics of flow batteries during charge and discharge, this embodiment develops a temperature control system suitable for high power density flow batteries. By employing a decentralized heat exchange and a centralized temperature control system, heat dissipation energy consumption is reduced, and it has the following advantages: 1. Eliminate or significantly reduce the static energy consumption of the energy storage system during periods when cooling is not required (such as low temperature environments or low load operation), including the energy consumption of the cooling system itself and the additional pump energy consumption caused by the flow resistance of the heat exchanger.

[0047] 2. Optimize the overall energy consumption of the energy storage system when cooling is required, and precisely control cooling as needed.

[0048] 3. Reduce the ineffective contact time between the electrolyte and the heat exchanger, reduce the risk of material corrosion and ion contamination caused by long-term contact, and extend the service life of the electrolyte and the heat exchanger.

[0049] 4. A specific flow path design, namely parallel temperature control branches and main circulation pipelines, makes it technically possible to use high-performance metal materials (such as titanium) for heat exchangers, leveraging their excellent thermal conductivity and corrosion resistance while controlling contamination risks. The electrolyte only flows through the titanium tube heat exchanger when cooling is required, significantly reducing its total contact time with the metal surface, slowing down corrosion and ion dissolution processes, and extending the service life of both the heat exchanger and the electrolyte itself. Because the contact time is controllable, a safe window is provided for using heat exchangers made of metal materials with better thermal conductivity and higher mechanical strength (such as titanium and special stainless steel), breaking the limitation of traditional flow batteries that often use plastic (such as PP and PFA) heat exchangers to avoid contamination, thus improving heat exchange efficiency and system compactness.

[0050] 5. Improve the integration and intelligence of the temperature control system, simplify the system structure, and reduce costs. Energy saving and consumption reduction directly lower the operating costs of the energy storage system.

[0051] 6. Enhanced project efficiency: Standardized modular design and centralized management system reduce on-site installation complexity, shorten construction cycle, and support rapid maintenance and expansion.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A flow battery temperature control system, characterized in that, Includes several flow battery energy storage cells (3) with the same structure that are distributedly connected to the centralized temperature management module (1). The flow battery energy storage cell (3) includes a positive electrode stack (16) and a negative electrode stack (18) symmetrically arranged on both sides of the proton exchange membrane (17). The top of the positive electrode stack (16) is connected to the top of the positive electrode storage tank (4), and the top of the negative electrode stack (18) is connected to the top of the negative electrode storage tank (14). The bottom of the positive electrode stack (16) and the bottom of the negative electrode stack (18) are respectively connected to the bottom side wall of the positive electrode storage tank (4) and the bottom side wall of the negative electrode storage tank (14) through a connecting pipeline structure. The connecting pipeline structure includes a secondary distribution system, a parallel branch module, a filter (22), a circulating pump (13), and a butterfly valve (5) connected in sequence through pipelines; and a temperature sensor (21) is provided on the pipeline between the secondary distribution system and the parallel branch module. The parallel branch module includes a main circulation pipeline for activation in non-cold operation mode and a temperature control branch for activation in refrigeration operation mode. The output of the centralized temperature management module (1) is electrically connected to the parallel branch module via a cable (2), and the input of the centralized temperature management module (1) is connected to the output of the temperature sensor (21). The centralized temperature management module (1) is used to obtain the real-time electrolyte temperature collected by the temperature sensor (21) after the electrolyte in the positive electrode storage tank (4) or negative electrode storage tank (14) flows through the butterfly valve (5), circulation pump (13), filter (22) and parallel branch module in sequence, and controls the opening and closing of the main circulation pipeline or temperature control branch according to the real-time electrolyte temperature.

2. The flow battery temperature control system according to claim 1, characterized in that, The main circulation pipeline is the main connection pipeline (20) equipped with a second solenoid valve (9).

3. The flow battery temperature control system according to claim 2, characterized in that, The temperature control branch is equipped with a heat exchanger (15). One end of the heat exchanger (15) is connected to one end of the pipeline equipped with a temperature sensor (21) through a branch connection pipeline (19). The other end of the heat exchanger (15) is connected to one end of the filter (22) through a branch connection pipeline (19). A first solenoid valve (8) is provided on the pipeline between the heat exchanger (15) and the filter (22).

4. The flow battery temperature control system according to claim 3, characterized in that, The pipelines connecting the input and output ends of the circulating pump (13) are respectively provided with a pump inlet expansion joint (6) and a pump outlet expansion joint (7).

5. The flow battery temperature control system according to claim 4, characterized in that, The secondary distribution system includes several stack inlet bellows (23) connected in parallel with the positive electrode stack (16) or the negative electrode stack (18). The stack inlet bellows (23) are connected to one end of the secondary distribution buffer chamber (12), and the secondary distribution buffer chamber (12) is connected to the inlet of the corresponding positive electrode stack (16) or negative electrode stack (18) through at least two stack inlet bellows (23). Meanwhile, the other end of the secondary distribution buffer chamber (12) is connected to a ball valve (11) and a flow sensor (10) in sequence through a pipeline.

6. An energy-saving method based on the flow battery temperature control system according to any one of claims 1 to 5, characterized in that, The specific steps include: S1: The temperature sensor (21) is used to monitor the current electrolyte temperature T in the corresponding pipeline in real time through the pre-set battery management system (BMS). S2: Set the temperature hysteresis range and determine the relationship between the current electrolyte temperature T and the temperature hysteresis range. If the current electrolyte temperature T is lower than the lower limit of the optimal operating temperature of the temperature hysteresis range, then execute S3; if the current electrolyte temperature T is within the temperature hysteresis range, then execute S4; if the current electrolyte temperature T is higher than the upper limit of the optimal operating temperature of the temperature hysteresis range, then execute S5. S3: The flow battery temperature control system is controlled to be in non-cooling operation mode by the centralized temperature management module (1), that is, the first solenoid valve (8) on the temperature control branch is closed and the second solenoid valve (9) on the main circulation pipeline is opened, and the electrolyte temperature is kept stable by opening the heat preservation device pre-set on the outside of the positive or negative electrode storage tank (14). S4: Maintain the current pipeline on / off status; S5: The centralized temperature management module (1) controls the flow battery temperature control system to be in the cooling operation mode, that is, controls the opening of the first solenoid valve (8) on the temperature control branch, and at the same time closes the second solenoid valve (9) on the main circulation pipeline or adjusts the opening ratio of the second solenoid valve (9) and the first solenoid valve (8), thereby optimizing the pumping energy consumption of the flow battery temperature control.

7. The energy-saving method for a flow battery temperature control system according to claim 6, characterized in that, The average pumping consumption corresponding to the optimization of pumping energy consumption for flow battery temperature control in S5 is: In the formula: This indicates the percentage of runtime during which the system requires cooling. These represent the average pump consumption, the pump consumption of the corresponding main circulation pipeline, and the pump consumption of the temperature control branch where the heat exchanger is located, respectively.

8. The energy-saving method for a flow battery temperature control system according to claim 7, characterized in that, The method for adjusting the opening ratio between the second solenoid valve and the first solenoid valve in S5 is as follows: S51: Obtain the temperature deviation between the current electrolyte temperature T and the set target temperature, and obtain the required cooling demand coefficient through a proportional-integral-derivative controller. for: In the formula: Indicates temperature deviation; Indicates the current electrolyte temperature; This indicates that the target temperature is set and is a temperature value within the temperature hysteresis interval; Indicates intermediate variables; Represents the controller coefficients of a proportional-integral-derivative controller; Indicates used to Functions restricted to the interval [0,1]; Indicates a time parameter; Indicates the cooling demand coefficient; S52: Define the valve opening degree of the first solenoid valve and the second solenoid valve as... According to the cooling demand coefficient Construct a system for solving valve opening. The collaborative solution equations are used to obtain the corresponding cooling demand coefficients. Valve opening ; And the expression for the collaborative solution equation is: In the formula: Indicates the total system traffic; This indicates the flow rate when the heat exchanger is operating at full capacity. This indicates the flow rate of the main circulation pipeline; Indicates valve opening degree and flow coefficient The calibration function; This indicates the voltage drop in the temperature control branch; This indicates the pressure drop in the main circulation pipeline; This indicates the pressure drop used to compensate for the pressure drop in the pipeline.

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