A flow battery system and method of implementing temperature control thereof, control device

Abstract

The application discloses a liquid flow battery system and a method and a control device for realizing temperature control, solves problems of poor reliability, uncontrollable shutdown, low energy efficiency and slow response of a liquid flow battery temperature control system through multi-point criterion, long-term shutdown temperature control, short-term shutdown low-power circulation, pre-stack heat exchange arrangement and other treatments, and realizes efficient temperature management in a full life cycle and under multiple working conditions. Embodiments of the application are suitable for temperature control of a liquid flow battery system under multiple temperature conditions, improve battery discharge efficiency, prolong battery life, and meet scheduling requirements of a power grid side.

Description

Technical Field

[0001] This application relates to, but is not limited to, the field of electrochemical energy storage system technology, and particularly to a flow battery system and the method and control device for achieving temperature control therewith. Background Technology

[0002] As new clean energy sources gradually replace traditional energy sources, energy storage systems, as a key component of the new energy system, play a vital supporting role in the development of the entire power generation industry. While clean energy resources such as wind and solar power are abundant, they are significantly affected by natural environmental factors, and their output power often fluctuates, making it difficult to provide a continuous and stable power supply to the grid. Therefore, utilizing energy storage batteries as a regulating link between the grid and new energy generation can effectively improve the stability and security of power supply.

[0003] Among various types of energy storage batteries, flow batteries have gradually gained widespread attention due to their advantages such as independent design of power and capacity, long cycle life, and high safety performance. However, the performance and lifespan of flow batteries are closely related to electrolyte temperature. When the electrolyte temperature deviates from the suitable range, it not only leads to a decrease in battery charging and discharging efficiency but may also cause long-term instability or even failure of the system. Therefore, ensuring the stable operation of flow batteries under different temperature conditions is of great significance for improving battery discharge efficiency, extending battery life, and meeting the dispatch requirements of the grid. Summary of the Invention

[0004] This application provides a flow battery system and a method and control device for temperature control, which can be applied to the temperature control of the flow battery system under multiple temperature conditions, improve battery discharge efficiency, extend battery life, and meet the dispatching requirements of the power grid.

[0005] This invention provides a flow battery system, comprising: a battery stack connected to a positive electrolyte circuit and a negative electrolyte circuit respectively; a positive electrolyte storage tank and a negative electrolyte storage tank respectively for storing the positive electrolyte and negative electrolyte; a first magnetic pump; a second magnetic pump; a temperature controller; a first heat exchanger; a second heat exchanger; and multiple electric valves and multiple temperature sensors; wherein,

[0006] The first magnetic pump is installed in the positive electrolyte circuit to drive the flow of the positive electrolyte;

[0007] The second magnetic pump is installed in the negative electrode electrolyte circuit to drive the flow of the negative electrode electrolyte;

[0008] The temperature controller has both cooling and heating functions. Its internal heat exchanger is led out and used as the first and second heat exchangers, respectively, and is set at the front end of the fuel cell inlet of the positive and negative electrolyte circuits, so that the refrigerant and electrolyte can directly exchange heat.

[0009] The flow battery system includes a positive electrode main circuit, a negative electrode main circuit, a positive electrode first bypass, a negative electrode first bypass, a positive electrode second bypass, and a negative electrode second bypass; among which,

[0010] The positive electrode main circuit and the negative electrode main circuit are used to realize the normal charge and discharge cycle of the electrolyte during normal operation. The positive electrode main circuit path includes: positive electrode electrolyte storage tank, first electric valve, first magnetic pump, first heat exchanger, second electric valve, positive electrode inlet of the fuel cell stack, positive electrode outlet of the fuel cell stack, and positive electrode electrolyte storage tank. The negative electrode main circuit path includes: negative electrode electrolyte storage tank, fifth electric valve, second magnetic pump, second heat exchanger, sixth electric valve, negative electrode inlet of the fuel cell stack, negative electrode outlet of the fuel cell stack, and negative electrode electrolyte storage tank.

[0011] The positive electrode first bypass and the negative electrode first bypass are used to independently regulate the temperature of the electrolyte when the system is shut down for a long period of time. The positive electrode first bypass path includes: positive electrode electrolyte storage tank, first electric valve, first magnetic pump, first heat exchanger, fourth electric valve, and positive electrode electrolyte storage tank (bypassing the fuel cell stack). The negative electrode first bypass path includes: negative electrode electrolyte storage tank, fifth electric valve, second magnetic pump, second heat exchanger, eighth electric valve, and negative electrode electrolyte storage tank.

[0012] The positive electrode second bypass and the negative electrode second bypass are branch pipelines set between the heat exchanger and the fuel cell stack in the main circuit. During short-term shutdowns, the electrolyte partially flows through the fuel cell stack and partially bypasses it. The positive electrode second bypass path includes: positive electrode electrolyte storage tank, first electric valve, first magnetic pump, third electric valve, and positive electrode electrolyte storage tank. The negative electrode second bypass path includes: negative electrode electrolyte storage tank, fifth electric valve, second magnetic pump, seventh electric valve, and positive electrode electrolyte storage tank.

[0013] In one exemplary instance, a control unit is also included for:

[0014] In normal operation mode, based on the temperature measurement point signals from the temperature sensor, if the temperature at at least two temperature measurement points simultaneously exceeds a first temperature threshold or falls below a second temperature threshold, the temperature controller is activated for cooling or heating; if the temperature at any one temperature measurement point returns to the target temperature, the temperature controller is turned off.

[0015] In long-term shutdown mode, when at least two temperature measuring points simultaneously exceed the third temperature threshold or fall below the fourth temperature threshold, the temperature controller is activated for cooling or heating until the temperature at any one of the measuring points returns to the target temperature. Then the temperature controller is shut down and switched to normal operation mode.

[0016] In short-term shutdown mode, when the temperature of at least two temperature measuring points is in the critical range, the temperature difference between the temperature measuring points before and after the positive and negative electrode stacks is collected respectively, and the opening of the corresponding shunt bypass valve is adjusted according to the temperature difference; when the temperature difference is less than the fourth temperature threshold, the bypass flow rate is increased and the main circuit flow rate is reduced accordingly until the temperature difference is greater than the fourth temperature threshold.

[0017] In one exemplary instance, the temperature points include 6 points, the positive electrode electrolyte circuit includes 3 temperature measuring points, and the negative electrode electrolyte circuit includes 3 temperature measuring points;

[0018] Each temperature measurement point is equipped with a temperature sensor;

[0019] The three temperature sensors installed in the positive electrode electrolyte circuit include: a third temperature sensor installed at the outlet of the positive electrode electrolyte tank, a first temperature sensor installed at the outlet of the first heat exchanger, and a second temperature sensor installed at the outlet of the fuel cell stack on the positive electrode side; the three temperature sensors installed in the negative electrode electrolyte circuit include: a sixth temperature sensor installed at the outlet of the negative electrode electrolyte tank, a fourth temperature sensor installed at the outlet of the second heat exchanger, and a fifth temperature sensor installed at the outlet of the fuel cell stack on the negative electrode side.

[0020] The plurality of electric valves may include:

[0021] The first electric valve is located between the outlet of the positive electrolyte storage tank and the first magnetic pump;

[0022] The second electric valve is installed on the positive main circuit near the positive inlet of the fuel cell stack;

[0023] The third electric valve is installed on the third positive electrode bypass and is used to control the electrolyte at the outlet of the first heat exchanger to bypass the fuel cell stack and directly return to the positive electrode electrolyte storage tank to achieve flow distribution.

[0024] The fourth electric valve is installed on the second positive electrode bypass near the inlet of the positive electrode electrolyte storage tank, so that the electrolyte bypasses the fuel cell stack and returns directly to the positive electrode electrolyte storage tank from the outlet of the first heat exchanger.

[0025] The fifth electric valve is located between the outlet of the negative electrode electrolyte storage tank and the second magnetic pump;

[0026] The sixth electric valve is located on the negative electrode main circuit near the negative electrode inlet of the fuel cell stack;

[0027] The seventh electric valve is installed on the third bypass of the negative electrode and is used to control the electrolyte at the outlet of the second heat exchanger to bypass the fuel cell stack and flow directly back to the negative electrode electrolyte storage tank to achieve flow distribution.

[0028] The eighth electric valve is installed on the second bypass of the negative electrode near the inlet of the negative electrode electrolyte storage tank, and is used to allow the electrolyte to bypass the fuel cell stack and return directly to the negative electrode electrolyte storage tank from the outlet of the second heat exchanger.

[0029] In one exemplary instance, during normal operation, the first electric valve, the second electric valve, the fifth electric valve, and the sixth electric valve are in the open state, while the third electric valve, the fourth electric valve, the seventh electric valve, and the eighth electric valve V8 are in the closed state.

[0030] When the temperature at at least two temperature measuring points in the positive electrode main circuit exceeds the first temperature threshold, the control unit controls the temperature controller to start cooling. When the temperature at any temperature measuring point in the positive electrode main circuit returns to the target temperature, the control unit controls the temperature controller to shut down. When the temperature at at least two temperature measuring points in the positive electrode main circuit is lower than the second temperature threshold, the control unit controls the temperature controller to start heating. When the temperature at any temperature measuring point in the positive electrode main circuit returns to the target temperature, the control unit controls the temperature controller to shut down.

[0031] When the temperature at at least two temperature measuring points in the negative electrode main circuit exceeds the first temperature threshold, the control unit controls the temperature controller to start cooling. When the temperature at any temperature measuring point in the positive electrode main circuit returns to the target temperature, the control unit controls the temperature controller to shut down. When the temperature at at least two temperature measuring points in the negative electrode main circuit is lower than the second temperature threshold, the control unit controls the temperature controller to start heating. When the temperature at any temperature measuring point in the negative electrode main circuit returns to the target temperature, the control unit controls the temperature controller to shut down.

[0032] In one exemplary instance, under the long-term shutdown mode, the first electric valve, the fourth electric valve, the fifth electric valve, and the eighth electric valve are in the open state, while the second electric valve, the third electric valve, the sixth electric valve, and the seventh electric valve are in the closed state.

[0033] When the temperature at at least two temperature measuring points in the first positive electrode bypass exceeds the third temperature threshold, the control unit controls the temperature controller to start cooling. At this time, the first electric valve and the fourth electric valve are opened, and the second electric valve and the third electric valve are closed. When the temperature at any temperature measuring point in the first positive electrode bypass returns to the target temperature, the control unit controls the temperature controller to shut down, and at the same time closes the fourth electric valve and opens the second electric valve.

[0034] When the temperature at at least two temperature measuring points in the first positive electrode bypass is lower than the fourth temperature threshold, the control unit controls the temperature controller to start heating. At this time, the first electric valve and the fourth electric valve are opened, and the second electric valve and the third electric valve are closed. When the temperature at any temperature measuring point in the first positive electrode bypass returns to the target temperature, the control unit controls the temperature controller to be turned off. At the same time, the fourth electric valve is closed and the second electric valve is opened.

[0035] When the temperature at at least two temperature measuring points in the first bypass of the negative electrode exceeds the third temperature threshold, the control unit controls the temperature controller to start cooling. At this time, the fifth electric valve and the eighth electric valve open, and the sixth electric valve and the seventh electric valve close. When the temperature at any temperature measuring point in the first bypass of the negative electrode returns to the target temperature, the control unit controls the temperature controller to shut down, and at the same time, closes the eighth electric valve and opens the sixth electric valve.

[0036] When the temperature at at least two temperature measuring points in the first bypass of the negative electrode is lower than the fourth temperature threshold, the control unit controls the temperature controller to start heating. At this time, the fifth electric valve and the eighth electric valve are opened, and the sixth electric valve and the seventh electric valve are closed. When the temperature at any temperature measuring point in the first bypass of the negative electrode returns to the target temperature, the control unit controls the temperature controller to shut down, and at the same time, the eighth electric valve is closed and the sixth electric valve is opened.

[0037] In one exemplary instance, when the temperatures of at least two temperature measuring points in the positive electrode main circuit and the positive electrode second bypass, as well as the negative electrode main circuit and the negative electrode second bypass, are in the first critical temperature range, the system switches to the low-temperature short-term shutdown mode.

[0038] In the short-term shutdown mode, the first electric valve, the second electric valve, the third electric valve, the fifth electric valve, the sixth electric valve, and the seventh electric valve are in the open state, while the fourth electric valve and the eighth electric valve are in the closed state.

[0039] When the temperature at least two temperature measuring points in the positive main circuit and the positive second bypass is greater than the fifth temperature threshold but less than the second temperature threshold, the control unit controls the temperature controller to start heating. At this time, the first electric valve opens, and the second and third electric valves operate according to the initial set opening degree. The opening ratio of the second and third electric valves is adjusted according to the temperature difference between the first and third temperature sensors. When the temperature difference is less than the fourth temperature threshold, the opening degree of the third electric valve is increased and the opening degree of the second electric valve is decreased until the temperature difference between the first and third temperature sensors is greater than the fourth temperature threshold.

[0040] When the temperature at least two temperature measuring points in the negative electrode main circuit and the negative electrode second bypass is greater than the fifth temperature threshold but less than the second temperature threshold, the control unit controls the temperature controller to start heating. At this time, the fifth electric valve opens, and the sixth and seventh electric valves operate according to the initial set opening degree. The opening ratio of the sixth and seventh electric valves is adjusted according to the temperature difference between the fourth and sixth temperature sensors. When the temperature difference is less than the fourth temperature threshold, the opening degree of the seventh electric valve is increased and the opening degree of the sixth electric valve is decreased until the temperature difference between the fourth and sixth temperature sensors is greater than the fourth temperature threshold.

[0041] In one exemplary instance, when the temperatures of at least two temperature measuring points in the positive electrode main circuit and the positive electrode second bypass, as well as the negative electrode main circuit and the negative electrode second bypass, are in the second critical temperature range, the system switches to the low-temperature short-term shutdown mode.

[0042] In the short-term shutdown mode, the first electric valve, the second electric valve, the third electric valve, the fifth electric valve, the sixth electric valve, and the seventh electric valve are in the open state, while the fourth electric valve and the eighth electric valve are in the closed state.

[0043] When the temperature at least two temperature measuring points in the positive main circuit and the positive second bypass is greater than the first temperature threshold but less than the third temperature threshold, the controlled temperature controller starts to cool. At this time, the first electric valve opens, and the second and third electric valves operate according to the initial set opening degree. The opening ratio of the second and third electric valves is adjusted according to the temperature difference between the first and third temperature sensors. When the temperature difference is less than the fourth temperature threshold, the opening degree of the third electric valve is increased and the opening degree of the second electric valve is decreased until the temperature difference between the first and third temperature sensors is greater than the fourth temperature threshold.

[0044] When the temperature at at least two temperature measuring points in the negative electrode main circuit and the negative electrode second bypass is greater than the first temperature threshold but less than the third temperature threshold, the control unit controls the temperature controller to start cooling. At this time, the fifth electric valve opens, and the sixth and seventh electric valves operate according to the initial set opening degree. The opening ratio of the sixth and seventh electric valves is adjusted according to the temperature difference between the fourth and sixth temperature sensors. When the temperature difference is less than the fourth temperature threshold, the opening degree of the seventh electric valve is increased and the opening degree of the sixth electric valve is decreased until the temperature difference between the fourth and sixth temperature sensors is greater than the fourth temperature threshold.

[0045] In one exemplary instance, the target temperature is 30 degrees Celsius; the first temperature threshold is 35 degrees Celsius; the second temperature threshold is 25 degrees Celsius; the third temperature threshold is 40 degrees Celsius; the fourth temperature threshold is 5 degrees Celsius; and the fifth temperature threshold is 0 degrees Celsius.

[0046] The temperature difference is 5°C.

[0047] This application also provides a method for achieving temperature control, characterized in that it is based on the flow battery system according to any one of claims 8; comprising:

[0048] Temperature values ​​at multiple measurement points are collected using multiple temperature sensors.

[0049] The electrolyte is circulated according to the corresponding working mode and the temperature controller is controlled based on the collected temperature value to ensure that the flow battery system operates within the target temperature range. The working modes are as follows: normal operation mode, positive and negative electrolytes circulate along the positive main circuit and negative main circuit, respectively; long-term shutdown mode, positive and negative electrolytes circulate along the positive first bypass and negative first bypass, respectively; and short-term shutdown mode, positive and negative electrolytes circulate along the positive second bypass and negative second bypass, respectively.

[0050] This application embodiment also provides a control device, including a memory and a processor, wherein the memory stores the following instructions that can be executed by the processor: steps for implementing the above-described temperature control method.

[0051] The flow battery system and its temperature control method provided in this application address the problems of poor reliability, uncontrollable shutdown, low energy efficiency, and slow response in flow battery temperature control systems through multi-point criteria, long-term shutdown temperature control, short-term shutdown low-power cycling, and in-pile heat exchange arrangement. This achieves efficient temperature management across the entire lifecycle and multiple operating conditions. This application is applicable to the temperature control of flow battery systems under various temperature conditions, improving battery discharge efficiency, extending battery life, and meeting the grid-side dispatch requirements.

[0052] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims and drawings. Attached Figure Description

[0053] The accompanying drawings are used to provide a further understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0054] Figure 1 This is a schematic diagram of the composition and structure of the flow battery system in the embodiments of this application;

[0055] Figure 2 This is a flowchart illustrating the method for temperature control in a flow battery system according to an embodiment of this application. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be arbitrarily combined with each other.

[0057] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be more thorough and complete.

[0058] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0059] It is understood that the terms "first" and "second" used in this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0060] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0061] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0062] The steps illustrated in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases the steps shown or described may be performed in a different order than that presented here.

[0063] While flow battery systems have developed some technical means for temperature control, several shortcomings remain. First, electrolyte temperature can typically only be regulated during normal battery operation. In cases of prolonged power outages, electrolyte temperature cannot be controlled independently, leading to deviations from the operating temperature range. Second, heat exchange devices are mostly installed only on the positive electrode side of the battery stack, lacking corresponding heat exchange units on the negative electrode side, making separate control of the positive and negative electrolytes difficult. Furthermore, when the electrolyte temperature is too high or too low, the system's protection mechanisms often prevent timely and rapid response to grid demands, weakening the flexibility of the energy storage system on the dispatch side.

[0064] Furthermore, heat exchangers in flow battery systems are often located at the stack outlet. While this structure can regulate electrolyte temperature to some extent, it increases the pressure of electrolyte entering the stack, which is detrimental to the safety of stack operation. Simultaneously, temperature control methods mostly rely on temperature signals from a single sensor. When the sensor malfunctions, the temperature control system will not function properly, posing a high risk of single point of failure. Finally, current systems primarily employ traditional cooling methods such as water cooling. These systems often require numerous auxiliary devices, resulting in high energy consumption. Their coefficient of performance (COP) is typically below 3, while direct cooling systems can achieve a COP greater than 5, thus also exhibiting certain shortcomings in energy efficiency.

[0065] To address any of the aforementioned technical problems, embodiments of this application provide a flow battery system, such as... Figure 1 As shown, it may include: a fuel cell stack connected to the positive electrolyte circuit and the negative electrolyte circuit respectively; a positive electrolyte storage tank and a negative electrolyte storage tank respectively for storing the positive electrolyte and the negative electrolyte; and a first magnetic pump (such as...). Figure 1 P1), second magnetic pump (such as ... Figure 1 P2), temperature controller, first heat exchanger (such as ... Figure 1 HT1), second heat exchanger (such as Figure 1 HT2), and multiple electric valves (such as Figure 1 (V1-V8), multiple temperature sensors (such as...) Figure 1 (01-06); among which,

[0066] The first magnetic pump is installed in the positive electrolyte circuit to drive the flow of the positive electrolyte;

[0067] The second magnetic pump is installed in the negative electrode electrolyte circuit to drive the flow of the negative electrode electrolyte;

[0068] The temperature controller has both cooling and heating functions. Its internal heat exchanger is led out and used as the first and second heat exchangers, respectively, and is set at the front end of the fuel cell inlet of the positive and negative electrolyte circuits, so that the refrigerant and electrolyte can directly exchange heat.

[0069] The flow battery system includes a positive electrode main circuit, a negative electrode main circuit, a positive electrode first bypass, a negative electrode first bypass, a positive electrode second bypass, and a negative electrode second bypass; among which,

[0070] Positive main circuit (e.g.) Figure 1 S1), negative main circuit (such as Figure 1 S4 is used to achieve the normal charge and discharge cycle of the electrolyte during normal system operation; the positive electrode main circuit path includes: positive electrode electrolyte storage tank, first electric valve, first magnetic pump, first heat exchanger, second electric valve, positive electrode inlet of the fuel cell stack, positive electrode outlet of the fuel cell stack, and positive electrode electrolyte storage tank; the negative electrode main circuit path includes: negative electrode electrolyte storage tank, fifth electric valve, second magnetic pump, second heat exchanger, sixth electric valve, negative electrode inlet of the fuel cell stack, negative electrode outlet of the fuel cell stack, and negative electrode electrolyte storage tank;

[0071] Positive first bypass (e.g.) Figure 1 S2), negative electrode first bypass (such as ... Figure 1 S5 is used to independently regulate the electrolyte temperature during long-term system shutdown to prevent the electrolyte from freezing or overheating due to excessively low temperature. The positive electrode first bypass path includes: positive electrode electrolyte storage tank, first electric valve, first magnetic pump, first heat exchanger, fourth electric valve, and positive electrode electrolyte storage tank (bypassing the fuel cell stack). The negative electrode first bypass path includes: negative electrode electrolyte storage tank, fifth electric valve, second magnetic pump, second heat exchanger, eighth electric valve, and negative electrode electrolyte storage tank (bypassing the fuel cell stack).

[0072] Positive second bypass (such as) Figure 1 S3), negative electrode second bypass (such as Figure 1S6), is a branch pipeline set between the heat exchanger and the fuel cell stack in the main circuit, so that during short-term shutdowns, part of the electrolyte flows through the fuel cell stack and part of it bypasses the fuel cell stack; the positive electrode second bypass path includes (diversion regulation bypass): positive electrode electrolyte storage tank, first electric valve, first magnetic pump, third electric valve, positive electrode electrolyte storage tank; the negative electrode second bypass path includes (diversion regulation bypass): negative electrode electrolyte storage tank, fifth electric valve, second magnetic pump, seventh electric valve, positive electrode electrolyte storage tank.

[0073] In one exemplary instance, the flow battery system of this application may further include a control unit for:

[0074] In normal operation mode, based on the temperature measurement signals from the temperature sensor, if the temperature at at least two measurement points simultaneously exceeds the first temperature threshold or falls below the second temperature threshold, the temperature controller is activated for cooling or heating; when the temperature at any one measurement point returns to the target temperature, the temperature controller is turned off.

[0075] In long-term shutdown mode, when at least two temperature measuring points simultaneously exceed the third temperature threshold or fall below the fourth temperature threshold, the temperature controller will be activated for cooling or heating until the temperature at any one of the measuring points returns to the target temperature. Then the temperature controller will be shut down and switched to normal operation mode.

[0076] In short-term shutdown mode, when the temperature of at least two temperature measuring points is in the critical range (such as 0℃-25℃ or 35℃-40℃), the control unit collects the temperature difference ΔT between the positive and negative electrode temperature measuring points before and after the stack, and adjusts the opening of the corresponding shunt bypass valve according to the temperature difference ΔT. When the temperature difference ΔT is less than the fourth temperature threshold, the bypass flow is increased and the main circuit flow is reduced accordingly until the temperature difference ΔT is greater than the fourth temperature threshold, thereby ensuring that the electrolyte still circulates through the stack at a low power during short-term shutdown to maintain electrolyte activity, and can quickly resume high-power operation when the grid has dispatch requirements.

[0077] The opening of the shunt valve is adjusted according to the temperature difference ΔT between the temperature measurement points before and after the fuel cell stack: when ΔT is less than the fourth temperature threshold, the third bypass flow is increased to maintain the electrolyte's low-power charging and discharging operation during short-term shutdowns, thereby maintaining the electrolyte's activity and ensuring that the system can quickly respond to grid dispatch requirements. In other words, ΔT is kept above the fourth temperature threshold, which allows the electrolyte to maintain low-power charging and discharging and keep its activity, while quickly restoring high-power response when the grid has dispatch requirements.

[0078] In one exemplary embodiment, the heat exchangers inside the temperature controller, namely the first and second heat exchangers, are located outside the temperature controller and directly connected to the electrolyte system pipeline, connecting them to the positive and negative electrolyte circuits, respectively. The refrigerant R410a circulates between the temperature controller and the heat exchangers, directly exchanging heat with the electrolyte within the heat exchangers, thereby achieving cooling or heating of the electrolyte. This embodiment of the application employs this direct-cooling heat exchange structure, reducing intermediate heat exchange links, improving heat exchange efficiency, and enabling the system to achieve a rated cooling efficiency ratio greater than 5.

[0079] In one exemplary instance, there are six temperature measurement points: three in the positive electrolyte circuit and three in the negative electrolyte circuit. In one embodiment, each temperature measurement point is equipped with at least one temperature sensor.

[0080] In one embodiment, such as Figure 1 As shown, the three temperature sensors installed in the positive electrode electrolyte circuit include: a third temperature sensor located at the outlet of the positive electrode electrolyte tank, a first temperature sensor located at the outlet of the first heat exchanger, and a second temperature sensor located at the outlet of the fuel cell stack on the positive electrode side. The three temperature sensors installed in the negative electrode electrolyte circuit include: a sixth temperature sensor located at the outlet of the negative electrode electrolyte tank, a fourth temperature sensor located at the outlet of the second heat exchanger, and a fifth temperature sensor located at the outlet of the fuel cell stack on the negative electrode side. This layout ensures that the temperature of the electrolyte can be monitored both before and after entering the stack. Furthermore, combined with the temperature difference ΔT control logic between the electrolyte tank outlet and the heat exchanger outlet, precise temperature control and bypass switching are achieved.

[0081] The flow battery system provided in this application addresses the problems of poor reliability, uncontrollable shutdown, low energy efficiency, and slow response inherent in flow battery temperature control systems through multi-point criteria, long-term shutdown temperature control, short-term shutdown low-power cycling, and pre-stack heat exchange arrangement. This achieves efficient temperature management across the entire lifecycle and multiple operating conditions. This application's embodiments are applicable to the temperature control of flow battery systems under various temperature conditions, improving battery discharge efficiency, extending battery life, and meeting grid-side dispatch requirements.

[0082] Specifically, the flow battery system provided in this application can satisfy the electrolyte temperature control function during normal system operation, and can also circulate and control the electrolyte temperature separately after the system has been shut down for a long time due to power failure; it can control the temperature of the positive and negative electrolytes separately; it can also quickly respond to the grid demand when the electrolyte temperature is too low or too high; the heat exchanger is installed in front of the stack to reduce the pressure of the electrolyte entering the stack; the temperature controller is only activated when the temperature of at least two temperature points exceeds the set temperature value, preventing the temperature control system from failing to operate normally due to sensor damage; only one temperature controller is needed outside the system to achieve simultaneous management of the electrolyte temperature of the positive and negative electrodes.

[0083] Furthermore, the temperature controller in the flow battery system provided in this application embodiment adopts a direct cooling method in which the refrigerant directly exchanges heat with the electrolyte, which greatly improves the energy efficiency ratio of the system, thereby reducing the power consumption during the cooling / heating process and lowering the operating cost of the energy storage system.

[0084] In one embodiment, during normal operation, the battery's operating path during normal charging and discharging includes a positive electrode main circuit path and a negative electrode main circuit path. In normal operation, when the temperature of at least two temperature measuring points in the same circuit simultaneously exceeds a first temperature threshold, the temperature controller is activated for cooling. In this case, the temperature controller is shut down when the temperature of any temperature measuring point in the circuit returns to the target temperature. Conversely, when the temperature of at least two temperature measuring points in the same circuit simultaneously falls below a second temperature threshold, the temperature controller is activated for heating. In this case, the temperature controller is shut down when the temperature of any temperature measuring point in the circuit returns to the target temperature.

[0085] In one embodiment, during long-term shutdown, the electrolyte does not enter the fuel cell stack. Instead, it circulates separately through the positive and negative electrode first bypass paths to prevent freezing or overheating due to excessively low electrolyte temperatures. During long-term shutdown, an electric valve switches to the first bypass (i.e., the bypass loop where the positive and negative electrode electrolytes circulate around the fuel cell stack), allowing the electrolyte to circulate only between the storage tank and the heat exchanger without passing through the fuel cell stack. This maintains the electrolyte temperature during shutdown, preventing freezing or overheating, and also avoids unnecessary flow exerting additional pressure on the fuel cell stack. When the temperature returns to the target temperature, the electric valve switches back to the main circuit, and the system resumes normal operation.

[0086] In one embodiment, during a short-term shutdown, the positive electrolyte circuit, through the proportional adjustment of diversion valves such as the second and third electric valves, allows part of the positive electrolyte to return to the positive electrolyte storage tank via the main positive circuit path through the fuel cell stack, and part to return to the positive electrolyte storage tank via the second positive bypass path, bypassing the fuel cell stack. Similarly, the negative electrolyte circuit, through the proportional adjustment of diversion valves such as the sixth and seventh electric valves, allows part of the negative electrolyte to return to the positive electrolyte storage tank via the main negative circuit path through the fuel cell stack, and part to return to the positive electrolyte storage tank via the second negative bypass path, bypassing the fuel cell stack. In short-term shutdown mode, the electric valves switch to a path that allows the electrolyte to circulate through the fuel cell stack at low power. The valve opening is controlled based on the temperature difference ΔT between the temperature measurement points before and after the electrolyte. When the temperature difference ΔT is less than a fourth temperature threshold (e.g., 5°C), the bypass valve opening is adjusted to increase the temperature difference ΔT, thereby maintaining low-power charging and discharging while the electrolyte temperature is within the critical range and responding promptly to grid dispatch.

[0087] Figure 2 This is a flowchart illustrating the method for temperature control in a flow battery system according to an embodiment of this application. Based on the flow battery system provided in this embodiment, such as... Figure 2 As shown, it may include:

[0088] Step 200: Collect temperature values ​​at multiple temperature measurement points using multiple temperature sensors.

[0089] In one exemplary instance, there are six temperature measurement points: three in the positive electrolyte circuit and three in the negative electrolyte circuit. In one embodiment, each temperature measurement point is equipped with at least one temperature sensor.

[0090] In one embodiment, three temperature sensors are installed in the positive electrolyte circuit, located at the outlet of the positive electrolyte tank, the outlet of the first heat exchanger, and the outlet of the fuel cell stack on the positive side, respectively. Similarly, three temperature sensors are installed in the negative electrolyte circuit, located at the outlet of the negative electrolyte tank, the outlet of the second heat exchanger, and the outlet of the fuel cell stack on the negative side, respectively. This arrangement ensures that the electrolyte temperature can be monitored both before and after entering the stack. Furthermore, combined with the temperature difference ΔT between the electrolyte tank outlet and the heat exchanger outlet, precise temperature control and bypass switching are achieved.

[0091] Step 201: Based on the corresponding operating mode, the electrolyte is circulated using the appropriate path. The temperature controller is adjusted according to the collected temperature values ​​to ensure the flow battery system operates within the target temperature range. Specifically, the operating modes are: normal operation mode (positive and negative electrolytes circulate along the positive and negative main circuits, respectively); long-term shutdown mode (positive and negative electrolytes circulate along the first positive and negative bypass circuits, respectively); and short-term shutdown mode (positive and negative electrolytes circulate along the second positive and negative bypass circuits, respectively).

[0092] In one exemplary instance, controlling a temperature controller based on collected temperature values ​​to ensure the flow battery system operates within a target temperature range includes:

[0093] In normal operation mode, based on the temperature measurement signals from the temperature sensor, if the temperature at at least two measurement points simultaneously exceeds the first temperature threshold or falls below the second temperature threshold, the temperature controller is activated for cooling or heating; when the temperature at any one measurement point returns to the target temperature, the temperature controller is turned off.

[0094] In long-term shutdown mode, when at least two temperature measuring points simultaneously exceed the third temperature threshold or fall below the fourth temperature threshold, the temperature controller will be activated for cooling or heating until the temperature at any one of the measuring points returns to the target temperature. Then the temperature controller will be shut down and switched to normal operation mode.

[0095] In short-term shutdown mode, when the temperature of at least two temperature measuring points is in the first critical temperature range (e.g., 0℃-25℃) or the second critical temperature range (e.g., 35℃-40℃), the control unit collects the temperature difference ΔT between the positive and negative electrode temperature measuring points before and after the stack, and adjusts the opening of the corresponding bypass valve according to the temperature difference ΔT. When the temperature difference ΔT is less than the fourth temperature threshold, the bypass flow is increased and the main circuit flow is reduced accordingly until the temperature difference ΔT is greater than the fourth temperature threshold, thereby ensuring that the electrolyte continues to circulate through the stack at a low power during short-term shutdown, maintaining the activity of the electrolyte, and can quickly resume high-power operation when the power grid has dispatch requirements.

[0096] The temperature control method for flow battery systems provided in this application addresses the problems of poor reliability, uncontrollable shutdown, low energy efficiency, and slow response inherent in flow battery temperature control systems through multi-point criteria, long-term shutdown temperature control, short-term shutdown low-power cycling, and in-pile heat exchange arrangement. This achieves efficient temperature management across the entire lifecycle and multiple operating conditions. This application's embodiments are applicable to the temperature control of flow battery systems under various temperature conditions, improving battery discharge efficiency, extending battery life, and meeting the grid-side dispatch requirements.

[0097] Specifically, the flow battery system provided in this application can satisfy the electrolyte temperature control function during normal system operation, and can also circulate and control the electrolyte temperature separately after the system has been shut down for a long time due to power failure; it can control the temperature of the positive and negative electrolytes separately; it can also quickly respond to the grid demand when the electrolyte temperature is too low or too high; the heat exchanger is installed in front of the stack to reduce the pressure of the electrolyte entering the stack; the temperature controller is only activated when the temperature of at least two temperature points exceeds the set temperature value, preventing the temperature control system from failing to operate normally due to sensor damage; only one temperature controller is needed outside the system to achieve simultaneous management of the electrolyte temperature of the positive and negative electrodes.

[0098] Furthermore, the temperature controller in the flow battery system provided in this application embodiment adopts a direct cooling method in which the refrigerant directly exchanges heat with the electrolyte, which greatly improves the energy efficiency ratio of the system, thereby reducing the power consumption during the cooling / heating process and lowering the operating cost of the energy storage system.

[0099] This application also provides a computer-readable storage medium storing computer-executable instructions for performing the temperature control method described in any of the preceding claims.

[0100] This application further provides a control device, including a memory and a processor, wherein the memory stores the following instructions executable by the processor: steps for performing the temperature control method described in any of the preceding claims.

[0101] In one exemplary instance, the plurality of electric valves in the embodiments of this application may include:

[0102] The first electric valve is installed between the outlet of the positive electrolyte storage tank and the first magnetic pump;

[0103] The second electric valve is located on the positive main circuit near the positive inlet of the fuel cell stack;

[0104] The third electric valve is installed on the third positive electrode bypass and is used to control the electrolyte at the outlet of the first heat exchanger to bypass the fuel cell stack and directly return to the positive electrode electrolyte storage tank to achieve flow distribution.

[0105] The fourth electric valve is located at the inlet of the positive electrode second bypass near the positive electrode electrolyte storage tank. It is used to allow the electrolyte to bypass the fuel cell stack and return directly to the positive electrode electrolyte storage tank from the outlet of the first heat exchanger.

[0106] The fifth electric valve is located between the outlet of the negative electrode electrolyte storage tank and the second magnetic pump;

[0107] The sixth electric valve is located on the negative electrode main circuit near the negative electrode inlet of the fuel cell stack.

[0108] The seventh electric valve, located on the third bypass of the negative electrode, is used to control the electrolyte at the outlet of the heat exchanger to bypass the fuel cell stack and flow directly back to the negative electrode electrolyte storage tank, thereby achieving flow distribution.

[0109] The eighth electric valve is located at the inlet of the negative electrode electrolyte storage tank on the second bypass of the negative electrode. It is used to allow the electrolyte to bypass the fuel cell stack and return directly to the negative electrode electrolyte storage tank from the outlet of the second heat exchanger.

[0110] The following is combined with Figure 1 Describe in detail the working principles under different working modes.

[0111] 1) Normal operating mode.

[0112] In normal operating mode, the system is in a regular charging and discharging state. At this time, the electrolyte temperature is generally controlled within the target temperature range, such as 25℃-35℃. Assuming the set operating temperature is 30℃ (i.e., the target temperature), for example... Figure 1 As shown, the positive and negative electrolytes circulate along path S1 (i.e., the positive main circuit), and the negative electrolyte circulates along path S4 (i.e., the negative main circuit). The temperature measuring points on path S1 on the positive side include measuring points 01, 02, and 03, and the temperature measuring points on path S4 on the negative side include measuring points 04, 05, and 06. At this time, the first electric valve V1, the second electric valve V2, the fifth electric valve V5, and the sixth electric valve V6 are in the open state, while the third electric valve V3, the fourth electric valve V4, the seventh electric valve V7, and the eighth electric valve V8 are in the closed state.

[0113] When the temperature at least two temperature measuring points in the positive electrode path S1 circulation system exceeds the first temperature threshold (e.g., 35℃), the temperature signal is fed back to the control unit, which controls the temperature controller to start cooling. When the temperature at any temperature measuring point in the positive electrode path S1 circulation system returns to the target temperature of 30℃, the control unit controls the temperature controller to shut down. When the temperature at at least two temperature measuring points in the positive electrode path S1 circulation system is lower than the second temperature threshold (e.g., 25℃), the temperature signal is fed back to the control unit, which controls the temperature controller to start heating. When the temperature at any temperature measuring point in the positive electrode path S1 circulation system returns to the target temperature of 30℃, the control unit controls the temperature controller to shut down.

[0114] When the temperature at least two temperature measuring points in the S4 circulation system on the negative electrode side exceeds the first temperature threshold (e.g., 35°C), the temperature signal is fed back to the control unit, which then controls the temperature controller to start cooling. When the temperature at any temperature measuring point in the S4 circulation system on the negative electrode side recovers to the target temperature of 30°C, the control unit controls the temperature controller to shut down. When the temperature at at least two temperature measuring points in the S4 circulation system on the negative electrode side is below the second temperature threshold (e.g., 25°C), the temperature signal is fed back to the control unit, which then controls the temperature controller to start heating. When the temperature at any temperature measuring point in the S4 circulation system on the negative electrode side recovers to the target temperature of 30°C, the control unit controls the temperature controller to shut down.

[0115] In this embodiment, under normal operating mode, to protect the battery system and further improve system reliability, three temperature measuring points are set on both the positive and negative electrode circulation systems. The temperature controller is only activated when the temperatures at two measuring points on each side exceed the set temperature value. During operation, the temperature controller stops if the temperature at even one measuring point exceeds the set temperature value, thus avoiding malfunctions caused by single-point sensor failures or deviations. Furthermore, in this embodiment, heat exchangers are installed on both the positive and negative electrode circulation systems, and these heat exchangers are located at the battery stack inlet to allow for temperature regulation before the electrolyte enters the battery stack, thereby reducing pressure fluctuations entering the battery stack. Through the above design, this embodiment requires only one temperature controller to achieve both cooling and heating of the positive and negative electrode electrolytes, and can independently control the temperature of the positive and negative electrode circuits respectively.

[0116] 2) Long-term shutdown mode.

[0117] In the long-term power outage shutdown mode, the system is in a power outage shutdown state. When the temperature at least two temperature measuring points in the positive electrode circulation system is below 0℃, and the temperature at least two temperature measuring points in the negative electrode circulation system is below 0℃; or, when the temperature at least two temperature measuring points in the positive electrode circulation system exceeds a third temperature threshold (e.g., 40℃), and the temperature at least two temperature measuring points in the negative electrode circulation system exceeds a third temperature threshold (e.g., 40℃), the system switches to long-term shutdown mode. In this case, if... Figure 1 As shown, the positive electrode electrolyte circulates along path S1-S2 (i.e., the first positive electrode bypass), and the negative electrode electrolyte circulates along path S4-S5 (i.e., the first negative electrode bypass). Temperature measuring points on path S1-S2 on the positive electrode side include measuring points 01 and 03, while temperature measuring points on path S4-S5 on the negative electrode side include measuring points 04 and 06. The corresponding electric valve states are: first electric valve V1, fourth electric valve V4, fifth electric valve V5, and eighth electric valve V8 are in the open state; second electric valve V2, third electric valve V3, sixth electric valve V6, and seventh electric valve V7 are in the closed state.

[0118] When the temperature at at least two temperature measuring points in the positive electrode side path S1-S2 circulation system exceeds the third temperature threshold (e.g., 40℃), the temperature signal is fed back to the control unit. The control unit then controls the temperature controller to start cooling. At this time, the first electric valve V1 and the fourth electric valve V4 are opened, while the second electric valve V2 and the third electric valve V3 are closed. When the temperature at any temperature measuring point in the positive electrode side path S1-S2 circulation system returns to the target temperature, such as reaching 30℃, the control unit controls the temperature controller to shut down, simultaneously closing the fourth electric valve V4 and opening the second electric valve V2, allowing the system to resume normal charging and discharging operation. When the temperature at least two temperature measuring points in the positive electrode path S1-S2 circulation system is lower than the fourth temperature threshold (e.g., 5℃), the temperature signal is fed back to the control unit. The control unit controls the temperature controller to start heating. At this time, the first electric valve V1 and the fourth electric valve V4 are opened, and the second electric valve V2 and the third electric valve V3 are closed. When the temperature at any temperature measuring point in the positive electrode path S1-S2 circulation system recovers to the target temperature, such as reaching 30℃, the control unit controls the temperature controller to shut down. At the same time, the fourth electric valve V4 is closed and the second electric valve V2 is opened, so that the system resumes normal charging and discharging operation.

[0119] When the temperature at at least two temperature measuring points in the negative electrode side path circulation system S4-S5 exceeds the third temperature threshold (e.g., 40℃), the temperature signal is fed back to the control unit. The control unit controls the temperature controller to start cooling. At this time, the fifth electric valve V5 and the eighth electric valve V8 are opened, and the sixth electric valve V6 and the seventh electric valve V7 are closed. When the temperature at any temperature measuring point in the negative electrode side path S4-S5 circulation system returns to the target temperature, such as reaching 30℃, the control unit controls the temperature controller to shut down. At the same time, the eighth electric valve V8 is closed and the sixth electric valve V6 is opened, so that the system resumes normal charging and discharging operation. When the temperature at at least two temperature measuring points in the negative electrode side path circulation system S4-S5 is lower than the fourth temperature threshold (e.g., 5℃), the temperature signal is fed back to the control unit. The control unit controls the temperature controller to start heating. At this time, the fifth electric valve V5 and the eighth electric valve V8 are opened, and the sixth electric valve V6 and the seventh electric valve V7 are closed. When the temperature at any temperature measuring point in the negative electrode side path circulation system S4-S5 recovers to the target temperature, such as reaching 30℃, the control unit controls the temperature controller to shut down. At the same time, the eighth electric valve V8 is closed and the sixth electric valve V6 is opened, so that the system resumes normal charging and discharging operation.

[0120] In long-term shutdown mode, to protect the battery system, three temperature measuring points are set on both the positive and negative electrode circulation systems. The temperature controller is only activated when at least two measuring points on each side exceed the set temperature value. During operation, the temperature controller stops as soon as any measuring point exceeds the set temperature value. This embodiment satisfies the system's temperature control requirements during normal operation and also enables independent electrolyte circulation temperature control via a first bypass after a long-term power outage. Furthermore, this solution requires only one temperature controller to simultaneously achieve cooling and heating.

[0121] 3) Short-term downtime mode.

[0122] In short-term shutdown mode, the system is in a non-charging / discharging state but needs to maintain electrolyte activity. When the temperature at least two temperature measuring points in the positive electrode loop system is within the first critical temperature range (e.g., 0℃-25℃), i.e., greater than 0℃ but less than the second temperature threshold (e.g., 25℃), and the temperature at least two temperature measuring points in the negative electrode loop system is greater than 0℃ but less than the second temperature threshold (e.g., 25℃), the system switches to low-temperature short-term shutdown mode. In this case, such as... Figure 1As shown, the positive electrode electrolyte circulates along paths S1 and S3 (i.e., the second positive electrode bypass), and the negative electrode electrolyte circulates along paths S4 and S6 (i.e., the second negative electrode bypass). The temperature measuring points on paths S1 and S3 on the positive electrode side include measuring points 01, 02, and 03; the temperature measuring points on paths S4 and S6 on the negative electrode side include measuring points 04, 05, and 06. The corresponding electric valve states are: first electric valve V1, second electric valve V2, third electric valve V3, fifth electric valve V5, sixth electric valve V6, and seventh electric valve V7 are in the open state; fourth electric valve V4 and eighth electric valve V8 are in the closed state.

[0123] In this embodiment, it is assumed that three temperature sensors are installed in the positive electrode electrolyte circuit: temperature sensor 03 at the outlet of the positive electrode electrolyte tank, temperature sensor 01 at the outlet of the first heat exchanger, and temperature sensor 02 at the outlet of the positive electrode stack. Three temperature sensors are installed in the negative electrode electrolyte circuit: temperature sensor 06 at the outlet of the negative electrode electrolyte tank, temperature sensor 04 at the outlet of the second heat exchanger, and temperature sensor 05 at the outlet of the negative electrode stack.

[0124] In the short-term shutdown mode of the system, when the temperature of at least two temperature measuring points in the circulation system on the positive electrode side is greater than the fifth temperature threshold (e.g., 0℃) but less than the second temperature threshold (e.g., 25℃), the temperature signal is fed back to the control unit. The control unit controls the temperature controller to start heating. At this time, the first electric valve V1 opens, and the second electric valve V2 and the third electric valve V3 operate according to the initial set opening degree. The system adjusts the opening ratio of the second electric valve V2 and the third electric valve V3 according to the temperature difference between temperature sensor 01 and temperature sensor 03. When the temperature difference is less than the fourth temperature threshold (e.g., 5℃), the opening degree of the third electric valve V3 is increased and the opening degree of the second electric valve V2 is decreased until the temperature difference between temperature sensor 01 and temperature sensor 03 is greater than the fourth temperature threshold (e.g., 5℃). This ensures that the electrolyte can be charged and discharged at low power through the stack, thereby maintaining the activity of the system and being able to respond to grid dispatch in a timely manner. When the temperature at at least two temperature measuring points in the circulation system on the negative electrode side is greater than the fifth temperature threshold (e.g., 0℃) but less than the second temperature threshold (e.g., 25℃), the temperature signal is fed back to the control unit. The control unit controls the temperature controller to start heating. At this time, the fifth electric valve V5 opens, and the sixth electric valve V6 and the seventh electric valve V7 operate according to the initial set opening degree. The system adjusts the opening ratio of the sixth electric valve V6 and the seventh electric valve V7 according to the temperature difference between temperature sensor 04 and temperature sensor 06. When the temperature difference is less than the fourth temperature threshold (e.g., 5℃), the opening degree of the seventh electric valve V7 is increased and the opening degree of the sixth electric valve V6 is decreased until the temperature difference between temperature sensor 04 and temperature sensor 06 is greater than the fourth temperature threshold (e.g., 5℃). This ensures that the electrolyte can be charged and discharged at low power through the stack, thereby maintaining the activity of the system and being able to respond to grid dispatch in a timely manner.

[0125] When the temperature at at least two temperature measuring points in the circulation system on the negative electrode side is within the second critical temperature range (e.g., 35℃-40℃), that is, greater than the first temperature threshold (e.g., 35℃) but less than the third temperature threshold (e.g., 40℃), such as Figure 1 As shown, the positive electrode electrolyte circulates along paths S1 and S3, and the negative electrode electrolyte circulates along paths S4 and S6. Temperature measuring points on paths S1 and S3 on the positive electrode side include measuring points 01, 02, and 03; temperature measuring points on paths S4 and S6 on the negative electrode side include measuring points 04, 05, and 06. The corresponding electric valve states are: first electric valve V1, second electric valve V2, third electric valve V3, fifth electric valve V5, sixth electric valve V6, and seventh electric valve V7 are in the open state; fourth electric valve V4 and eighth electric valve V8 are in the closed state.

[0126] When the temperature at at least two temperature measuring points in the positive electrode circulation system is greater than the first temperature threshold (e.g., 35℃) but less than the third temperature threshold (e.g., 40℃), the temperature signal is fed back to the control unit, which controls the start of the temperature controller to perform cooling. At this time, the first electric valve V1 opens, and the second electric valve V2 and the third electric valve V3 operate according to the initial set opening degree. The system adjusts the opening ratio of the second electric valve V2 and the third electric valve V3 according to the temperature difference between temperature sensor 01 and temperature sensor 03. When the temperature difference is less than the fourth temperature threshold (e.g., 5℃), the opening degree of the third electric valve V3 is increased and the opening degree of the second electric valve V2 is decreased until the temperature difference between temperature sensor 01 and temperature sensor 03 is greater than the fourth temperature threshold (e.g., 5℃). This ensures that the electrolyte undergoes low-power charging and discharging through the stack, thereby maintaining the activity of the system and enabling timely response to grid dispatch. When the temperature at at least two temperature measuring points in the circulation system on the negative electrode side is greater than the first temperature threshold (e.g., 35℃) but less than the third temperature threshold (e.g., 40℃), the temperature signal is fed back to the control unit. The control unit controls the temperature controller to start cooling. At this time, the fifth electric valve V5 opens, and the sixth electric valve V6 and the seventh electric valve V7 operate according to the initial set opening degree. The system adjusts the opening ratio of the sixth electric valve V6 and the seventh electric valve V7 according to the temperature difference between temperature sensor 04 and temperature sensor 06. When the temperature difference is less than the fourth temperature threshold (e.g., 5℃), the opening degree of the seventh electric valve V7 is increased and the opening degree of the sixth electric valve V6 is decreased until the temperature difference between temperature sensor 04 and temperature sensor 06 is greater than the fourth temperature threshold (e.g., 5℃). This ensures that the electrolyte undergoes low-power charging and discharging through the stack, thereby maintaining the activity of the system and enabling timely response to grid dispatch.

[0127] In short-term shutdown mode, to protect the battery system, three temperature measuring points are set on both the positive and negative electrode circulation systems. The temperature controller is only activated when the temperatures at two measuring points on each side exceed the set temperature value, thus avoiding malfunctions caused by single-point sensor failures. When the electrolyte temperature is in a low or high range, the system can still quickly respond to grid demands through low-power circulation. In this embodiment, only one temperature controller is needed to simultaneously achieve cooling and heating of both the positive and negative electrodes.

[0128] Although the embodiments disclosed in this application are as described above, the content described is merely for the purpose of understanding this application and is not intended to limit this application. Any person skilled in the art to which this application pertains may make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in this application; however, the scope of patent protection of this application shall still be determined by the scope defined in the appended claims.

Claims

1. A flow battery system, characterized in that, include: The device includes an electrode stack connected to the positive and negative electrolyte circuits respectively, positive and negative electrolyte storage tanks for storing the positive and negative electrolytes respectively, a first magnetic pump, a second magnetic pump, a temperature controller, a first heat exchanger, a second heat exchanger, multiple electric valves, and multiple temperature sensors; among which, The first magnetic pump is installed in the positive electrolyte circuit to drive the flow of the positive electrolyte; The second magnetic pump is installed in the negative electrode electrolyte circuit to drive the flow of the negative electrode electrolyte; The temperature controller has both cooling and heating functions. Its internal heat exchanger is led out and used as the first and second heat exchangers, respectively, and is set at the front end of the fuel cell inlet of the positive and negative electrolyte circuits, so that the refrigerant and electrolyte can directly exchange heat. The flow battery system includes a positive electrode main circuit, a negative electrode main circuit, a positive electrode first bypass, a negative electrode first bypass, a positive electrode second bypass, and a negative electrode second bypass; among which, The positive electrode main circuit and the negative electrode main circuit are used to realize the normal charge and discharge cycle of the electrolyte during normal operation. The positive electrode main circuit path includes: positive electrode electrolyte storage tank, first electric valve, first magnetic pump, first heat exchanger, second electric valve, positive electrode inlet of the fuel cell stack, positive electrode outlet of the fuel cell stack, and positive electrode electrolyte storage tank. The negative electrode main circuit path includes: negative electrode electrolyte storage tank, fifth electric valve, second magnetic pump, second heat exchanger, sixth electric valve, negative electrode inlet of the fuel cell stack, negative electrode outlet of the fuel cell stack, and negative electrode electrolyte storage tank. The positive electrode first bypass and the negative electrode first bypass are used to independently regulate the temperature of the electrolyte when the system is shut down for a long period of time. The positive electrode first bypass path includes: positive electrode electrolyte storage tank, first electric valve, first magnetic pump, first heat exchanger, fourth electric valve, and positive electrode electrolyte storage tank; the negative electrode first bypass path includes: negative electrode electrolyte storage tank, fifth electric valve, second magnetic pump, second heat exchanger, eighth electric valve, and negative electrode electrolyte storage tank. The positive electrode second bypass and the negative electrode second bypass are branch pipelines set between the heat exchanger and the fuel cell stack in the main circuit. During short-term shutdowns, the electrolyte partially flows through the fuel cell stack and partially bypasses it. The positive electrode second bypass path includes: positive electrode electrolyte storage tank, first electric valve, first magnetic pump, third electric valve, and positive electrode electrolyte storage tank. The negative electrode second bypass path includes: negative electrode electrolyte storage tank, fifth electric valve, second magnetic pump, seventh electric valve, and positive electrode electrolyte storage tank.

2. The flow battery system according to claim 1 further includes a control unit, configured to: In normal operation mode, based on the temperature measurement point signals from the temperature sensor, if the temperature at at least two temperature measurement points simultaneously exceeds a first temperature threshold or falls below a second temperature threshold, the temperature controller is activated for cooling or heating; if the temperature at any one temperature measurement point returns to the target temperature, the temperature controller is turned off. In long-term shutdown mode, when at least two temperature measuring points simultaneously exceed the third temperature threshold or fall below the fourth temperature threshold, the temperature controller is activated for cooling or heating until the temperature at any one of the measuring points returns to the target temperature. Then the temperature controller is shut down and switched to normal operation mode. In short-term shutdown mode, when the temperature of at least two temperature measuring points is in the critical range, the temperature difference between the temperature measuring points before and after the positive and negative electrode stacks is collected respectively, and the opening of the corresponding shunt bypass valve is adjusted according to the temperature difference; when the temperature difference is less than the fourth temperature threshold, the bypass flow rate is increased and the main circuit flow rate is reduced accordingly until the temperature difference is greater than the fourth temperature threshold.

3. The flow battery system according to claim 2, wherein, The temperature measuring points include 6 points, the positive electrode electrolyte circuit includes 3 temperature measuring points, and the negative electrode electrolyte circuit includes 3 temperature measuring points; Each temperature measurement point is equipped with a temperature sensor; The three temperature sensors installed in the positive electrode electrolyte circuit include: a third temperature sensor installed at the outlet of the positive electrode electrolyte tank, a first temperature sensor installed at the outlet of the first heat exchanger, and a second temperature sensor installed at the outlet of the fuel cell stack on the positive electrode side; the three temperature sensors installed in the negative electrode electrolyte circuit include: a sixth temperature sensor installed at the outlet of the negative electrode electrolyte tank, a fourth temperature sensor installed at the outlet of the second heat exchanger, and a fifth temperature sensor installed at the outlet of the fuel cell stack on the negative electrode side. The plurality of electric valves include: The first electric valve is located between the outlet of the positive electrolyte storage tank and the first magnetic pump; The second electric valve is installed on the positive main circuit near the positive inlet of the fuel cell stack; The third electric valve is installed on the third positive electrode bypass and is used to control the electrolyte at the outlet of the first heat exchanger to bypass the fuel cell stack and directly return to the positive electrode electrolyte storage tank to achieve flow distribution. The fourth electric valve is installed on the second positive electrode bypass near the inlet of the positive electrode electrolyte storage tank, so that the electrolyte bypasses the fuel cell stack and returns directly to the positive electrode electrolyte storage tank from the outlet of the first heat exchanger. The fifth electric valve is located between the outlet of the negative electrode electrolyte storage tank and the second magnetic pump; The sixth electric valve is located on the negative electrode main circuit near the negative electrode inlet of the fuel cell stack; The seventh electric valve is installed on the third bypass of the negative electrode and is used to control the electrolyte at the outlet of the second heat exchanger to bypass the fuel cell stack and flow directly back to the negative electrode electrolyte storage tank to achieve flow distribution. The eighth electric valve is installed on the second bypass of the negative electrode near the inlet of the negative electrode electrolyte storage tank, and is used to allow the electrolyte to bypass the fuel cell stack and return directly to the negative electrode electrolyte storage tank from the outlet of the second heat exchanger.

4. The flow battery system according to claim 3, wherein, In the normal operating mode, the first electric valve, the second electric valve, the fifth electric valve, and the sixth electric valve are in the open state, while the third electric valve, the fourth electric valve, the seventh electric valve, and the eighth electric valve are in the closed state. When the temperature at at least two temperature measuring points in the positive electrode main circuit exceeds the first temperature threshold, the control unit controls the temperature controller to start cooling. When the temperature at any temperature measuring point in the positive electrode main circuit returns to the target temperature, the control unit controls the temperature controller to shut down. When the temperature at at least two temperature measuring points in the positive electrode main circuit is lower than the second temperature threshold, the control unit controls the temperature controller to start heating. When the temperature at any temperature measuring point in the positive electrode main circuit returns to the target temperature, the control unit controls the temperature controller to shut down. When the temperature at at least two temperature measuring points in the negative electrode main circuit exceeds the first temperature threshold, the control unit controls the temperature controller to start cooling. When the temperature at any temperature measuring point in the negative electrode main circuit returns to the target temperature, the control unit controls the temperature controller to shut down. When the temperature at at least two temperature measuring points in the negative electrode main circuit is lower than the second temperature threshold, the control unit controls the temperature controller to start heating. When the temperature at any temperature measuring point in the negative electrode main circuit returns to the target temperature, the control unit controls the temperature controller to shut down.

5. The flow battery system according to claim 4, wherein, In the long-term shutdown mode, the first electric valve, the fourth electric valve, the fifth electric valve, and the eighth electric valve are in the open state, while the second electric valve, the third electric valve, the sixth electric valve, and the seventh electric valve are in the closed state. When the temperature at at least two temperature measuring points in the first positive electrode bypass exceeds the third temperature threshold, the control unit controls the temperature controller to start cooling. At this time, the first electric valve and the fourth electric valve are opened, and the second electric valve and the third electric valve are closed. When the temperature at any temperature measuring point in the first positive electrode bypass returns to the target temperature, the control unit controls the temperature controller to shut down, and at the same time closes the fourth electric valve and opens the second electric valve. When the temperature at at least two temperature measuring points in the first positive electrode bypass is lower than the fourth temperature threshold, the control unit controls the temperature controller to start heating. At this time, the first electric valve and the fourth electric valve are opened, and the second electric valve and the third electric valve are closed. When the temperature at any temperature measuring point in the first positive electrode bypass returns to the target temperature, the control unit controls the temperature controller to be turned off. At the same time, the fourth electric valve is closed and the second electric valve is opened. When the temperature at at least two temperature measuring points in the first bypass of the negative electrode exceeds the third temperature threshold, the control unit controls the temperature controller to start cooling. At this time, the fifth electric valve and the eighth electric valve open, and the sixth electric valve and the seventh electric valve close. When the temperature at any temperature measuring point in the first bypass of the negative electrode returns to the target temperature, the control unit controls the temperature controller to shut down, and at the same time, closes the eighth electric valve and opens the sixth electric valve. When the temperature at at least two temperature measuring points in the first bypass of the negative electrode is lower than the fourth temperature threshold, the control unit controls the temperature controller to start heating. At this time, the fifth electric valve and the eighth electric valve are opened, and the sixth electric valve and the seventh electric valve are closed. When the temperature at any temperature measuring point in the first bypass of the negative electrode returns to the target temperature, the control unit controls the temperature controller to shut down, and at the same time, the eighth electric valve is closed and the sixth electric valve is opened.

6. The flow battery system according to claim 5, wherein, When the temperatures of at least two temperature measuring points in the positive electrode main circuit and the positive electrode second bypass, as well as the negative electrode main circuit and the negative electrode second bypass, are in the first critical temperature range, switch to low temperature short-term shutdown mode. In the short-term shutdown mode, the first electric valve, the second electric valve, the third electric valve, the fifth electric valve, the sixth electric valve, and the seventh electric valve are in the open state, while the fourth electric valve and the eighth electric valve are in the closed state. When the temperature at least two temperature measuring points in the positive main circuit and the positive second bypass is greater than the fifth temperature threshold but less than the second temperature threshold, the control unit controls the temperature controller to start heating. At this time, the first electric valve opens, and the second and third electric valves operate according to the initial set opening degree. The opening ratio of the second and third electric valves is adjusted according to the temperature difference between the first and third temperature sensors. When the temperature difference is less than the fourth temperature threshold, the opening degree of the third electric valve is increased and the opening degree of the second electric valve is decreased until the temperature difference between the first and third temperature sensors is greater than the fourth temperature threshold. When the temperature at least two temperature measuring points in the negative electrode main circuit and the negative electrode second bypass is greater than the fifth temperature threshold but less than the second temperature threshold, the control unit controls the temperature controller to start heating. At this time, the fifth electric valve opens, and the sixth and seventh electric valves operate according to the initial set opening degree. The opening ratio of the sixth and seventh electric valves is adjusted according to the temperature difference between the fourth and sixth temperature sensors. When the temperature difference is less than the fourth temperature threshold, the opening degree of the seventh electric valve is increased and the opening degree of the sixth electric valve is decreased until the temperature difference between the fourth and sixth temperature sensors is greater than the fourth temperature threshold.

7. The flow battery system according to claim 5, wherein, When the temperature of at least two temperature measuring points in the positive electrode main circuit and the positive electrode second bypass, as well as the negative electrode main circuit and the negative electrode second bypass, is in the second critical temperature range, switch to low temperature short-term shutdown mode. In the short-term shutdown mode, the first electric valve, the second electric valve, the third electric valve, the fifth electric valve, the sixth electric valve, and the seventh electric valve are in the open state, while the fourth electric valve and the eighth electric valve are in the closed state. When the temperature at at least two temperature measuring points in the positive main circuit and the positive second bypass is greater than the first temperature threshold but less than the third temperature threshold, the control unit controls the temperature controller to start cooling. At this time, the first electric valve opens, and the second and third electric valves operate according to the initial set opening degree. The opening ratio of the second and third electric valves is adjusted according to the temperature difference between the first and third temperature sensors. When the temperature difference is less than the fourth temperature threshold, the opening degree of the third electric valve is increased and the opening degree of the second electric valve is decreased until the temperature difference between the first and third temperature sensors is greater than the fourth temperature threshold. When the temperature at at least two temperature measuring points in the negative electrode main circuit and the negative electrode second bypass is greater than the first temperature threshold but less than the third temperature threshold, the control unit controls the temperature controller to start cooling. At this time, the fifth electric valve opens, and the sixth and seventh electric valves operate according to the initial set opening degree. The opening ratio of the sixth and seventh electric valves is adjusted according to the temperature difference between the fourth and sixth temperature sensors. When the temperature difference is less than the fourth temperature threshold, the opening degree of the seventh electric valve is increased and the opening degree of the sixth electric valve is decreased until the temperature difference between the fourth and sixth temperature sensors is greater than the fourth temperature threshold.

8. The flow battery system according to claim 6, wherein, The target temperature is 30°C; the first temperature threshold is 35°C; the second temperature threshold is 25°C; the third temperature threshold is 40°C; the fourth temperature threshold is 5°C; and the fifth temperature threshold is 0°C. The temperature difference is 5°C.

9. A method for achieving temperature control, characterized in that, The flow battery system according to any one of claims 1-8; comprising: Temperature values ​​at multiple measurement points are collected using multiple temperature sensors. The electrolyte is circulated according to the corresponding working mode and the temperature controller is controlled based on the collected temperature value to ensure that the flow battery system operates within the target temperature range. The working modes are as follows: normal operation mode, positive and negative electrolytes circulate along the positive main circuit and negative main circuit, respectively; long-term shutdown mode, positive and negative electrolytes circulate along the positive first bypass and negative first bypass, respectively; and short-term shutdown mode, positive and negative electrolytes circulate along the positive second bypass and negative second bypass, respectively.

10. A control device, comprising a memory and a processor, wherein, The memory stores the following instructions that can be executed by the processor: for performing the steps of the method for implementing temperature control as described in claim 9.

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