Flow battery circulation loop system, control method and flow battery

Abstract

The invention discloses a flow battery circulation loop system, a control method and a flow battery. The system comprises an electric pile, a liquid storage device, a liquid storage exhaust device, a circulation control module and a circulation pipeline, the circulating pipeline comprises a first pipeline, a second pipeline and a third pipeline; the output end of the liquid storage device is communicated with the input end of the galvanic pile through a first pipeline, the output end of the galvanic pile is communicated with the input end of the liquid storage device through a second pipeline, and the liquid storage exhaust device is communicated with the second pipeline through a third pipeline; the circulation control module is started when the system is started, the electrolyte is pumped into the electric pile from the liquid storage device through the first pipeline, and the electrolyte is pumped into the liquid storage device from the electric pile through the second pipeline; and the liquid storage and exhaust device is used for storing the electrolyte when the system is started and exhausting gas in the circulating pipeline, and exhausting the stored electrolyte and sucking external gas when the system is closed. The exhaust efficiency of the circulating pipeline can be improved, a safety valve and an electronic switch are not needed, and the cost is reduced.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of battery technology, and in particular to a liquid flow battery circulation loop system, a control method and a liquid flow battery. Background Art

[0002] As a highly efficient and scalable energy storage technology, flow batteries have been widely used in various fields in recent years.

[0003] A typical liquid flow battery system includes a fuel cell stack, a liquid storage tank, a circulation pipeline, and a matching pump and valve control device. During operation, the electrolyte is driven by a pump to flow through the fuel cell stack and returns to the liquid storage tank after charging and discharging. After the system stops running, the electrolyte flows back to the liquid storage tank, and the fuel cell stack and the pipeline are refilled with air. In the standby state, the fuel cell stack will release hydrogen due to self-discharge. However, the exhaust efficiency of existing liquid flow battery systems is low during the startup phase. After shutdown, there will be residual electrolyte in the circulation pipeline, resulting in the risk of pipeline corrosion, and when the liquid flow battery is in the standby state, there will be a safety hazard of hydrogen accumulation. The existing technology usually uses various safety valves and electronic switches to achieve exhaust, and realizes gas management through real-time monitoring and frequent starting and stopping of pumps and valves. Although such solutions can partially improve performance, they significantly increase the complexity of the system. Summary of the invention

[0004] The present invention provides a liquid flow battery circulation loop system, a control method and a liquid flow battery, so as to improve the exhaust efficiency of a circulation pipeline without using a safety valve and an electronic switch, thereby reducing the cost.

[0005] In a first aspect, an embodiment of the present invention provides a liquid flow battery circulation loop system, the system comprising a battery stack, a liquid storage device, a liquid storage exhaust device, a circulation control module and a circulation pipeline;

[0006] The circulation pipeline includes a first pipeline, a second pipeline and a third pipeline; the output end of the liquid storage device is connected to the input end of the battery stack through the first pipeline, the output end of the battery stack is connected to the input end of the liquid storage device through the second pipeline, and the liquid storage exhaust device is connected to the second pipeline through the third pipeline;

[0007] The liquid storage device is used to store electrolyte; the battery stack is used to generate electricity through the electrolyte;

[0008] The circulation control module is used to start when the system is started, pump the electrolyte from the liquid storage device into the fuel cell stack through the first pipeline, and pump the electrolyte from the fuel cell stack into the liquid storage device through the second pipeline;

[0009] The liquid storage and exhaust device is used to store the electrolyte and exhaust the gas in the circulation pipeline when the system is started, and to exhaust the stored electrolyte and inhale external gas when the system is shut down.

[0010] Optionally, the circulation pipeline further includes a fourth pipeline;

[0011] The liquid storage and exhaust device is connected to the liquid storage device through a fourth pipeline; the liquid storage and exhaust device is also connected to the external environment;

[0012] The circulation control module is also used to shut down when the system is shut down; the fourth pipeline is also used to discharge the electrolyte in the liquid storage exhaust device to the liquid storage device when the system is shut down;

[0013] The third pipeline is also used to introduce the gas generated in the battery stack into the liquid storage and exhaust device when the system is in standby mode, and to exhaust the gas generated in the battery stack through the liquid storage and exhaust device.

[0014] Optionally, the circulation pipeline further includes a fifth pipeline;

[0015] The liquid storage exhaust device is connected to the external environment through a fifth pipeline.

[0016] Optionally, the gas comprises hydrogen.

[0017] Optionally, the liquid storage and exhaust device is located at a first height, the battery stack is located at a second height, and the liquid storage device is located at a third height;

[0018] The first height is greater than the second height and the third height.

[0019] Optionally, the highest point of the circulation pipeline is less than the first height.

[0020] Optionally, the circulation control module includes a first pump and a second pump, the first pump is arranged in the first pipeline, and the second pump is arranged in the second pipeline;

[0021] The first pump is used to pump the electrolyte from the liquid storage device into the fuel cell stack; the second pump is used to pump the electrolyte from the fuel cell stack into the liquid storage device.

[0022] Optionally, the circulation control module further includes a control module;

[0023] The control module is connected to the first pump and the second pump respectively;

[0024] The control module is used to control the first pump and the second pump to start working when the system is started, so that the electrolyte circulates between the liquid storage device and the battery stack, and the electrolyte in the second pipeline flows into the liquid storage exhaust device through the third pipeline, and the gas in the circulation pipeline is discharged through the liquid storage exhaust device; the control module is also used to control the first pump and the second pump to stop working when the system is shut down, so that the electrolyte in the battery stack flows into the liquid storage device through the second pipeline.

[0025] In a second aspect, an embodiment of the present invention further provides a control method for a liquid flow battery circulation loop system, the control method being applied to the liquid flow battery circulation loop system according to any embodiment of the present invention, the control method comprising:

[0026] When the system is started, the electrolyte is pumped from the liquid storage device into the fuel cell stack through the first pipeline, and the electrolyte is pumped from the fuel cell stack into the liquid storage device through the second pipeline.

[0027] In a third aspect, an embodiment of the present invention further provides a liquid flow battery, wherein the liquid flow battery comprises the liquid flow battery circulation loop system described in any embodiment of the present invention.

[0028] The present invention provides a liquid flow battery circulation loop system, a control method and a liquid flow battery. The liquid flow battery circulation loop system comprises a battery stack, a liquid storage device, a liquid storage exhaust device, a circulation control module and a circulation pipeline; the circulation pipeline comprises a first pipeline, a second pipeline and a third pipeline; the output end of the liquid storage device is connected to the input end of the battery stack through the first pipeline, the output end of the battery stack is connected to the input end of the liquid storage device through the second pipeline, the liquid storage exhaust device is connected to the second pipeline through the third pipeline, and the gas in the circulation pipeline can be quickly discharged through the third pipeline; the liquid storage device can store electrolyte; the battery stack can generate electricity through the electrolyte; The circulation control module can be started when the system is started, and the electrolyte is pumped from the liquid storage device into the battery stack through the first pipeline, and the electrolyte is pumped from the battery stack into the liquid storage device through the second pipeline; the liquid storage exhaust device can store electrolyte when the system is started, and discharge the gas in the circulation pipeline, so as to quickly reach the charging and discharging conditions of the battery stack, and the liquid storage exhaust device can also discharge the stored electrolyte and inhale external gas when the system is shut down, so as to avoid a large amount of electrolyte remaining in the circulation pipeline or the battery stack; in addition, when the system is on standby, the hydrogen generated by the battery stack can escape naturally through the third pipeline and the liquid storage exhaust device, without relying on a forced hydrogen discharge device. The present invention does not need to set redundant components such as safety valves and electronic switches, which reduces manufacturing costs, and can achieve efficient gas emissions and electrolyte control in the entire cycle of startup, operation, shutdown and standby, while avoiding reliability risks brought by complex additional devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of the structure of a liquid flow battery circulation loop system provided by an embodiment of the present invention;

[0030] Figure 2 A schematic structural diagram of another liquid flow battery circulation loop system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0032] The existing flow battery circulation loop faces multiple challenges in gas and electrolyte management. There is an urgent need for an integrated, low-cost solution that can achieve efficient gas emission and electrolyte control throughout the entire cycle of startup, operation, shutdown and standby, while avoiding the reliability risks brought by complex additional devices.

[0033] The embodiment of the present invention aims at solving the technical bottlenecks of gas management, electrolyte residue and system complexity of the existing liquid flow battery circulation loop, and provides a liquid flow battery circulation loop system. Through an integrated and low-cost solution, it can achieve efficient gas emission and electrolyte control in the entire cycle of startup, operation, shutdown and standby, while avoiding the reliability risks brought by complex additional devices. Figure 1 A schematic diagram of a flow battery circulation system according to an embodiment of the present invention is shown in FIG. Figure 1 As shown, the liquid flow battery circulation loop system includes a battery stack 110, a liquid storage device 120, a liquid storage exhaust device 130, a circulation control module 140 and a circulation pipeline 150.

[0034] The circulation pipeline 150 includes a first pipeline 151, a second pipeline 152 and a third pipeline 153; the output end of the liquid storage device 120 is connected to the input end of the fuel cell stack 110 through the first pipeline 151, the output end of the fuel cell stack 110 is connected to the input end of the liquid storage device 120 through the second pipeline 152, and the liquid storage exhaust device 130 is connected to the second pipeline 152 through the third pipeline 153.

[0035] The liquid storage device 120 is used to store electrolyte; the fuel cell stack 110 is used to generate electricity using the electrolyte; the circulation control module 140 is used to start when the system is started, pump the electrolyte from the liquid storage device 120 into the fuel cell stack 110 through the first pipeline 151, and pump the electrolyte from the fuel cell stack 110 into the liquid storage device 120 through the second pipeline 152; the liquid storage exhaust device 130 is used to store electrolyte when the system is started, and to exhaust the gas in the circulation pipeline 150, and to exhaust the stored electrolyte and inhale external gas when the system is shut down.

[0036] Among them, the liquid storage and exhaust device 130 can be an empty box. During the operation of the system, the electrolyte in the second pipe 152 will flow into the liquid storage and exhaust device 130 through the third pipe 153, so that the liquid storage and exhaust device 130 stores a certain amount of electrolyte during the operation of the system. The liquid flow battery circulation loop system and the liquid flow battery are started at the same time. The start time of the system is also the start time of the liquid flow battery, and the shutdown time of the system is also the shutdown time of the liquid flow battery. The liquid storage and exhaust device 130 can be connected to the external environment. When the system is started, the gas in the first pipe 151 and the second pipe 152 flows into the liquid storage and exhaust device 130 from the third pipe 153, so that the liquid storage and exhaust device 130 can discharge the gas in the circulation pipe 150, so that the battery stack 110 quickly reaches the charging and discharging conditions; and when the system is in standby, hydrogen will be generated due to the self-discharge of the battery stack 110. Because of the existence of the liquid storage and exhaust device 130, the hydrogen escapes upward, avoiding the accumulation of hydrogen in the circulation pipe 150 and reducing the safety risk. Furthermore, the liquid storage exhaust device 130 can discharge the stored electrolyte and inhale external gas when the system is shut down, so that the electrolyte quickly flows back to the liquid storage device 120, reducing the system shutdown time and preventing a large amount of electrolyte from remaining in the circulation pipe 150 or the battery stack 110. Optionally, the circulation control module 140 can be arranged on the first pipe 151 and the second pipe 152, or at both ends of the first pipe 151 and the second pipe 152. Figure 1 Only the situation where the circulation control module 140 is disposed on the first pipeline 151 and the second pipeline 152 is shown, and the flow of the electrolyte in the first pipeline 151 and the second pipeline 152 is controlled by the circulation control module 140 .

[0037] Specifically, the circulation pipeline 150 includes a first pipeline 151, a second pipeline 152 and a third pipeline 153; the output end of the liquid storage device 120 is connected to the input end of the fuel cell stack 110 through the first pipeline 151, and the output end of the fuel cell stack 110 is connected to the input end of the liquid storage device 120 through the second pipeline 152. The liquid storage device 120 stores electrolyte. The circulation control module 140 is started when the system is started, and the electrolyte is pumped from the liquid storage device 120 into the fuel cell stack 110 through the first pipeline 151, and the electrolyte is pumped from the fuel cell stack 110 into the liquid storage device 120 through the second pipeline 152, so that the fuel cell stack 110 can generate electricity through the electrolyte. The liquid storage and exhaust device 130 is connected to the second pipeline 152 through the third pipeline 153. The liquid storage and exhaust device 130 can store electrolyte when the system is started and discharge the gas in the circulation pipeline 150, so as to quickly reach the charging and discharging conditions of the battery stack 110. The liquid storage and exhaust device 130 can also discharge the stored electrolyte and inhale external gas when the system is shut down to avoid a large amount of electrolyte remaining in the circulation pipeline 150 or the battery stack 120; in addition, when the system is on standby, the hydrogen generated by the battery stack can escape naturally through the third pipeline 153 and the liquid storage and exhaust device 130 without relying on a forced hydrogen discharge device. The liquid flow battery circulation loop system implemented in the present invention eliminates redundant components such as safety valves and electronic switches, which can reduce manufacturing costs, and can achieve efficient gas exhaust and electrolyte control in the entire cycle of startup, operation, shutdown and standby, while avoiding reliability risks brought by complex additional devices.

[0038] The embodiment of the present invention provides a liquid flow battery circulation loop system, which includes a battery stack, a liquid storage device, a liquid storage exhaust device, a circulation control module and a circulation pipeline; the circulation pipeline includes a first pipeline, a second pipeline and a third pipeline; the output end of the liquid storage device is connected to the input end of the battery stack through the first pipeline, the output end of the battery stack is connected to the input end of the liquid storage device through the second pipeline, the liquid storage exhaust device is connected to the second pipeline through the third pipeline, and the gas in the circulation pipeline can be quickly exhausted through the third pipeline; the liquid storage device can store electrolyte; the battery stack can generate electricity through the electrolyte; the circulation control module The module can be started when the system is started, and the electrolyte is pumped from the liquid storage device into the battery stack through the first pipeline, and the electrolyte is pumped from the battery stack into the liquid storage device through the second pipeline; the liquid storage exhaust device can store electrolyte when the system is started, and discharge the gas in the circulation pipeline, so as to quickly reach the charging and discharging conditions of the battery stack, and the liquid storage exhaust device can also discharge the stored electrolyte and inhale external gas when the system is shut down, so as to avoid a large amount of electrolyte remaining in the circulation pipeline or the battery stack; in addition, when the system is on standby, the hydrogen generated by the battery stack can escape naturally through the third pipeline and the liquid storage exhaust device, without relying on a forced hydrogen discharge device. The present invention does not need to set redundant components such as safety valves and electronic switches, which reduces manufacturing costs, and can achieve efficient gas emissions and electrolyte control in the entire cycle of startup, operation, shutdown and standby, while avoiding reliability risks brought by complex additional devices.

[0039] The embodiment of the present invention is to further realize: Figure 2 A schematic diagram of another liquid flow battery circulation loop system provided by an embodiment of the present invention is shown in FIG. Figure 2 As shown,

[0040] The circulation pipeline 150 further includes a fourth pipeline 154 ; the liquid storage and exhaust device 130 is connected to the liquid storage device 120 via the fourth pipeline 154 ; the liquid storage and exhaust device 130 is also connected to the external environment.

[0041] The circulation control module 140 is also used to close when the system is shut down; the fourth pipeline 154 is also used to discharge the electrolyte in the liquid storage and exhaust device 130 to the liquid storage device 120 when the system is shut down; the third pipeline 153 is also used to introduce the gas generated in the battery stack 110 into the liquid storage and exhaust device 130 when the system is in standby mode, and discharge the gas generated in the battery stack 110 through the liquid storage and exhaust device 130.

[0042] Among them, the circulation control module 140 is turned off when the liquid flow battery circulation loop system is shut down, and turned on when the liquid flow battery circulation loop system is turned on. It is turned on and off synchronously with the liquid flow battery circulation loop system. When the circulation control module 140 is turned off, the electrolyte is stopped from being pumped from the liquid storage device 120 into the battery stack 110, and the electrolyte is also stopped from being pumped from the battery stack 110 into the liquid storage device 120, but the electrolyte in the battery stack 110 will naturally flow back to the liquid storage device 120.

[0043] Specifically, when the system is shut down, the electrolyte in the liquid storage and exhaust device 130 can be discharged to the liquid storage device 120 through the third pipe 153 and the fourth pipe 154, and because the liquid storage and exhaust device 130 is connected to the external environment, it can inhale air from the external environment, so that the electrolyte in the circulation pipeline 150 and the battery stack 110 can quickly flow back to the liquid storage device 120, thereby reducing the system shutdown time and avoiding a large amount of electrolyte remaining in the circulation pipeline 150 and the battery stack 110. In addition, because the liquid storage and exhaust device 130 is connected to the external environment, when the system is in the standby state, a certain amount of gas will still be generated in the battery stack 110. The third pipe 153 can introduce the gas generated in the battery stack 110 into the liquid storage and exhaust device 130, and discharge the gas generated in the battery stack 110 through the liquid storage and exhaust device 130, thereby avoiding the accumulation of gas generated in the battery stack 110 and improving the safety of the liquid flow battery.

[0044] Optionally, the gas comprises hydrogen.

[0045] Specifically, when the system is in standby mode, a certain amount of hydrogen will be generated in the fuel cell stack 110, and the gas in the fuel cell stack 110 needs to be discharged. When the system is in standby mode, the hydrogen generated by the fuel cell stack 110 can escape naturally through the third pipeline 153 and the liquid storage exhaust device 130, without relying on a forced hydrogen discharge device, and without installing redundant components such as safety valves and electronic switches, which significantly reduces the manufacturing cost, and can promptly discharge the hydrogen generated by the fuel cell stack 110 to avoid hydrogen accumulation and reduce safety issues.

[0046] Optionally, the circulation pipeline 150 further includes a fifth pipeline 155 ; the liquid storage and exhaust device 130 is connected to the external environment via the fifth pipeline 155 .

[0047] Specifically, the liquid storage exhaust device 130 is connected to the external environment through the fifth pipe 155. The external environment can be a safe atmospheric environment, which is conducive to the discharge of gas and hydrogen in the pipeline, so that the exhaust process of the circulation pipeline 150 is quickly completed during the system startup process, so as to quickly reach the charging and discharging conditions. At the same time, during the system standby process, the gas in the circulation loop can be discharged immediately. The liquid storage exhaust device 130 can also inhale external gas through the fifth pipe 155, so that the electrolyte in the circulation pipeline 150 and the battery stack 110 can quickly flow back to the liquid storage device 120, thereby reducing the system shutdown time and avoiding a large amount of electrolyte remaining in the circulation pipeline 150 and the battery stack 110.

[0048] Optionally, the liquid storage and exhaust device 130 is located at a first height, the fuel cell stack 110 is located at a second height, and the liquid storage device 120 is located at a third height; the first height is greater than the second height and the third height.

[0049] Specifically, since the first height is greater than the second height and the third height, that is, the height of the liquid storage and exhaust device 130 is greater than the heights of the battery stack 110 and the liquid storage device 120, it is convenient for the gas in the circulation pipe 150, the battery stack 110 and the liquid storage device 120 to escape to the liquid storage and exhaust device 130, and it is convenient for the liquid storage and exhaust device 130 to quickly discharge the gas in the circulation pipe 150, the battery stack 110 and the liquid storage device 120.

[0050] It should be noted that, since the liquid storage and exhaust device 130 is higher than the battery stack 110 and the liquid storage device 120, when the electrolyte rises to a certain height in the liquid storage and exhaust device 130, the gravity of the liquid and the liquid pressure in the circulation pipe 150 will reach a balance, and the height of the electrolyte in the liquid storage and exhaust device 130 will not continue to rise, and the liquid level will be fixed. The circulation control module 140 can control the liquid pressure in the circulation pipe 150, thereby controlling the liquid level of the electrolyte in the liquid storage and exhaust device 130.

[0051] Optionally, the highest point of the circulation pipe 150 is smaller than the first height.

[0052] Specifically, if the highest point of the circulation pipe 150 is lower than the first height, then the highest point of the circulation pipe 150 is lower than the height of the liquid storage and exhaust device 130, thereby facilitating the discharge of gas in the circulation pipe 150 and preventing part of the gas from accumulating in the circulation pipe 150 and being unable to be discharged.

[0053] It should be noted that in the prior art, when the existing liquid flow battery is in standby mode, the stack of the existing liquid flow battery will continue to produce a small amount of hydrogen due to the self-discharge reaction. Most existing systems use a safety valve combined with a downward extending hydrogen discharge pipeline to introduce hydrogen below the liquid level of the storage tank. However, the density of hydrogen is much lower than that of the electrolyte. This design forces the hydrogen to flow downward against the density gradient, resulting in low exhaust efficiency. During long-term operation, hydrogen tends to accumulate at the bends of the pipeline or at the top of the stack to form an explosive mixed gas (the explosion limit of hydrogen is 4%-75%). According to industry statistics, about 12% of liquid flow battery failures are directly related to improper hydrogen management, including sensor false alarms, leakage caused by aging of seals, etc. Through the settings of the above embodiments, the above problems can be solved, the accumulation of hydrogen can be avoided, and the cost is relatively low.

[0054] Optionally, the circulation control module 140 includes a first pump 141 and a second pump 142, the first pump 141 is arranged in the first pipeline 151, and the second pump 142 is arranged in the second pipeline 152; the first pump 141 is used to pump the electrolyte from the liquid storage device 120 into the fuel cell stack 110; the second pump 142 is used to pump the electrolyte from the fuel cell stack 110 into the liquid storage device 120.

[0055] Specifically, the first pump 141 is disposed in the first pipe 151, and the second pump 142 is disposed in the second pipe 152. The first pump 141 can pump electrolyte from the liquid storage device 120 into the battery stack 110; the second pump 142 can pump electrolyte from the battery stack 110 into the liquid storage device 120. When the second pump 142 pumps electrolyte from the battery stack 110 into the liquid storage device 120, the electrolyte is also pumped from the second pipe 152 into a portion of the third pipe 153, so that a certain height of electrolyte exists in the liquid storage and exhaust device 130.

[0056] It should be noted that the circulation control module 140 is not limited to the first pump 141 and the second pump 142 , and other pumps may be adaptively arranged in each pipeline in the circulation pipeline 150 to maintain the liquid pressure in the circulation pipeline 150 .

[0057] Optionally, the circulation control module 140 further includes a control module 143; the control module 143 is connected to the first pump 141 and the second pump 142 respectively.

[0058] The control module 143 is used to control the first pump 141 and the second pump 142 to start working when the system is started, so that the electrolyte circulates between the liquid storage device 120 and the battery stack 110, and the electrolyte in the second pipeline 152 flows into the liquid storage and exhaust device 130 through the third pipeline 153, and the gas in the circulation pipeline 150 is discharged through the liquid storage and exhaust device 130; the control module 143 is also used to control the first pump 141 and the second pump 142 to stop working when the system is shut down, so that the electrolyte in the battery stack 110 flows into the liquid storage device 120 through the second pipeline 152.

[0059] Specifically, when the system is started, the control module 143 controls the first pump 141 and the second pump 142 to start working, so that the electrolyte circulates between the liquid storage device 120 and the battery stack 110, and the electrolyte in the second pipe 152 flows into the liquid storage and exhaust device 130 through the third pipe 153, and the gas in the circulation pipe 150 is discharged through the liquid storage and exhaust device 130; when the system is shut down, the control module 143 controls the first pump 141 and the second pump 142 to stop working, so that the electrolyte in the battery stack 110 flows into the liquid storage device 120 through the second pipe 152.

[0060] Optionally, the liquid storage exhaust device 130 preferably adopts corrosion-resistant materials to prevent the electrolyte from causing serious corrosion to the liquid storage exhaust device 130.

[0061] It should be noted that in the prior art, after the liquid flow battery system is shut down, the electrolyte flows back to the liquid storage tank by gravity, and air remains in the stack and pipeline. When restarting, the electrolyte needs to be re-injected into the circulation loop and the internal gas is discharged. The prior art usually relies on the continuous operation of the circulation pump to gradually remove the gas, but due to the lack of a dedicated exhaust structure in the pipeline design, the gas is easy to form a gas blockage at the high point of the pipeline or in the stack, resulting in a slow electrolyte filling speed. Experiments show that the startup time of the traditional system accounts for about 15%-20% of the overall operating time, which seriously restricts the need for rapid response of the system. In addition, the presence of gas blockage may cause local overheating and accelerate the degradation of the stack membrane material. In addition, when the system is shut down, the electrolyte needs to be completely returned to the liquid storage tank to avoid residue. However, the existing pipeline design often has "liquid traps" (such as U-bends or horizontal sections), which causes part of the electrolyte to be retained. The active substances (such as vanadium ions) in the residual electrolyte will electrochemically corrode with the metal parts of the pipeline, shortening the life of the equipment. In addition, residual liquid may crystallize and block the pipeline, increasing the difficulty of restarting. In order to alleviate the above problems, the prior art usually adds electronic switch valves, gas sensors and multi-stage safety valves to achieve gas management through real-time monitoring and frequent start-stop of pump valves. Although such solutions can partially improve performance, they significantly increase the complexity of the system. In addition, the long-term stability of electronic components is greatly affected by humidity and temperature, and they are prone to failure in harsh environments. The structural design of the circulation pipeline 150 and the liquid storage and exhaust device 130 of the embodiment of the present invention can solve the above technical problems, and can achieve efficient gas emission and electrolyte control in the entire cycle of startup, operation, shutdown and standby, while avoiding the reliability risks brought by complex additional devices.

[0062] The embodiments of the present invention provide a liquid flow battery circulation loop system, which can achieve the following beneficial effects: 1. By quickly removing the gas in the circulation pipeline, the startup time of the system is reduced; 2. The hydrogen generated by the battery stack can be naturally released, which greatly reduces the risk of hydrogen accumulation; 3. By accelerating the discharge of the electrolyte in the circulation pipeline by inhaling gas, the shutdown time of the system is reduced, and the residual electrolyte in the circulation pipeline is greatly reduced, thereby reducing the corrosion risk of the circulation pipeline; 4. By eliminating redundant components such as safety valves and electronic switches, the manufacturing cost is reduced, and efficient gas emission and electrolyte control can be achieved in the entire cycle of startup, operation, shutdown and standby, while avoiding the reliability risks brought by complex additional devices.

[0063] An embodiment of the present invention further provides a control method for a liquid flow battery circulation loop system. The control method is applied to a liquid flow battery circulation loop system of any embodiment of the present invention. The control method includes:

[0064] When the system is started, the electrolyte is pumped from the liquid storage device into the fuel cell stack through the first pipe, and the electrolyte is pumped from the fuel cell stack into the liquid storage device through the second pipe.

[0065] Specifically, refer to Figure 1-2 When the system is started, the electrolyte is pumped from the liquid storage device 120 into the battery stack 110 through the first pipe 151, and the electrolyte is pumped from the battery stack 110 into the liquid storage device 120 through the second pipe 152. During this process, the gas in the first pipe 151, the second pipe 152 and the battery stack 110 can be discharged through the liquid storage exhaust device 130, so that the liquid flow battery can quickly reach the charging and discharging conditions. In addition, during the operation of the system, there will be a certain height of electrolyte in the liquid storage exhaust device 130, which can maintain the sealing of the system operation process. At the same time, the liquid storage exhaust device 130 can also timely discharge the gas in the circulation pipe 150, greatly improving the safety of the system.

[0066] The embodiment of the present invention provides a control method for a circulation loop system of a liquid flow battery, the control method comprising: when the system is started, the electrolyte is pumped from the liquid storage device into the battery stack through the first pipeline, and the electrolyte is pumped from the battery stack into the liquid storage device through the second pipeline, the liquid storage exhaust device can store the electrolyte when the system is started, and discharge the gas in the circulation pipeline, so as to quickly reach the charging and discharging conditions of the battery stack, and the liquid storage exhaust device can also discharge the stored electrolyte and inhale external gas when the system is shut down, so as to avoid a large amount of electrolyte remaining in the circulation pipeline or the battery stack; in addition, when the system is on standby, the hydrogen generated by the battery stack can escape naturally through the third pipeline and the liquid storage exhaust device, without relying on a forced hydrogen discharge device. The present invention does not need to set redundant components such as safety valves and electronic switches, which reduces manufacturing costs, and can achieve efficient gas discharge and electrolyte control in the entire cycle of startup, operation, shutdown and standby, while avoiding reliability risks brought by complex additional devices.

[0067] An embodiment of the present invention further provides a liquid flow battery, which includes the liquid flow battery circulation loop system in the above embodiment, thereby realizing the functions and technical effects of the liquid flow battery circulation loop system in the above embodiment.

[0068] In addition, the liquid flow battery of the embodiment of the present invention includes but is not limited to the liquid flow battery circulation loop system in the above embodiment, and corresponding modules can also be set according to the specific functional adaptability of the system in which the liquid flow battery is located.

[0069] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A liquid flow battery circulation loop system, characterized in that: The system includes a battery stack, a liquid storage device, a liquid storage exhaust device, a circulation control module and a circulation pipeline; The circulation pipeline includes a first pipeline, a second pipeline and a third pipeline; the output end of the liquid storage device is connected to the input end of the battery stack through the first pipeline, the output end of the battery stack is connected to the input end of the liquid storage device through the second pipeline, and the liquid storage exhaust device is connected to the second pipeline through the third pipeline; The liquid storage device is used to store electrolyte; the battery stack is used to generate electricity through the electrolyte; The circulation control module is used to start when the system is started, pump the electrolyte from the liquid storage device into the fuel cell stack through the first pipeline, and pump the electrolyte from the fuel cell stack into the liquid storage device through the second pipeline; The liquid storage and exhaust device is used to store the electrolyte and exhaust the gas in the circulation pipeline when the system is started, and to exhaust the stored electrolyte and inhale external gas when the system is shut down.

2. The liquid flow battery circulation loop system according to claim 1, characterized in that: The circulation pipeline also includes a fourth pipeline; The liquid storage and exhaust device is connected to the liquid storage device through the fourth pipeline; the liquid storage and exhaust device is also connected to the external environment; The circulation control module is also used to close when the system is shut down; the fourth pipeline is also used to discharge the electrolyte in the liquid storage and exhaust device to the liquid storage device when the system is shut down; The third pipeline is also used to introduce the gas generated in the battery stack into the liquid storage and exhaust device when the system is in a standby state, and to exhaust the gas generated in the battery stack through the liquid storage and exhaust device.

3. The liquid flow battery circulation loop system according to claim 2, characterized in that: The circulation pipeline also includes a fifth pipeline; The liquid storage and exhaust device is connected to the external environment through the fifth pipeline.

4. The liquid flow battery circulation loop system according to claim 2, characterized in that: The gas includes hydrogen.

5. The liquid flow battery circulation loop system according to claim 1, characterized in that: The liquid storage and exhaust device is located at a first height, the battery stack is located at a second height, and the liquid storage device is located at a third height; The first height is greater than the second height and the third height.

6. The liquid flow battery circulation loop system according to claim 5, characterized in that: The highest point of the circulation pipeline is smaller than the first height.

7. The liquid flow battery circulation loop system according to claim 1, characterized in that: The circulation control module includes a first pump and a second pump, wherein the first pump is arranged in the first pipeline, and the second pump is arranged in the second pipeline; The first pump is used to pump the electrolyte from the liquid storage device into the battery stack; the second pump is used to pump the electrolyte from the battery stack into the liquid storage device.

8. The liquid flow battery circulation loop system according to claim 7, characterized in that: The circulation control module also includes a control module; The control module is connected to the first pump and the second pump respectively; The control module is used to control the first pump and the second pump to start working when the system is started, so that the electrolyte circulates between the liquid storage device and the battery stack, and the electrolyte in the second pipeline flows into the liquid storage and exhaust device through the third pipeline, and the gas in the circulation pipeline is discharged through the liquid storage and exhaust device; the control module is also used to control the first pump and the second pump to stop working when the system is shut down, so that the electrolyte in the battery stack flows into the liquid storage device through the second pipeline.

9. A control method for a liquid flow battery circulation loop system, characterized in that: The control method is applied to the liquid flow battery circulation loop system according to any one of claims 1 to 8, and the control method comprises: When the system is started, the electrolyte is pumped from the liquid storage device into the fuel cell stack through the first pipeline, and the electrolyte is pumped from the fuel cell stack into the liquid storage device through the second pipeline.

10. A liquid flow battery, characterized in that: The liquid flow battery comprises the liquid flow battery circulation loop system according to any one of claims 1-8.

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