Exhaust gas treatment system and exhaust gas treatment method for flow battery

Abstract

The invention relates to an exhaust gas treatment system and an exhaust gas treatment method of a flow battery. The exhaust treatment system is used for treating gas exhausted by the flow battery, and the flow battery comprises a flow battery stack; the electrolyte storage device is provided with a liquid inlet, a liquid outlet, an air inlet and an air outlet, and is communicated with the flow battery stack through the liquid inlet and the liquid outlet to form an electrolyte loop; the exhaust treatment system comprises a carrier gas device which is communicated with the gas inlet and is configured to introduce carrier gas into the electrolyte storage device; and the exhaust gas pretreatment device communicates with the gas outlet and is configured to pretreat the gas flow discharged from the gas outlet. The exhaust treatment system can quickly exhaust hydrogen, the exhaust efficiency is improved, the safety risk caused by too high hydrogen concentration is effectively avoided, and the exhausted hydrogen can be recycled.

Description

Technical Field

[0001] The present application relates to the technical field of flow batteries, and particularly to an exhaust gas treatment system and an exhaust gas treatment method for flow batteries. Background Art

[0002] As an electrochemical energy storage method, a flow battery system has many advantages such as high safety, long cycle life, and the ability to store unstable energy from photovoltaic, wind power, etc. Among them, for example, a water-based flow battery energy storage system may generate hydrogen during operation. If the hydrogen is not quickly discharged, the flammability and explosiveness of hydrogen will increase the safety risk of the energy storage system, and the hydrogen generation process will consume electric energy and reduce the efficiency of the energy storage system. In addition, how to recycle the discharged hydrogen is also a difficult point in this field. Summary of the Invention

[0003] Based on this, it is necessary to provide an exhaust gas treatment system and an exhaust gas treatment method for a flow battery in view of the above-mentioned technical problems.

[0004] An exhaust gas treatment system for a flow battery is used to treat the gas discharged from the flow battery. Among them, the flow battery includes:

[0005] A flow battery stack;

[0006] An electrolyte storage device, which is provided with a liquid inlet, a liquid outlet, a gas inlet, and a gas outlet. The electrolyte storage device forms an electrolyte circuit with the flow battery stack through the liquid inlet and the liquid outlet.

[0007] The exhaust gas treatment system includes:

[0008] A carrier gas device, which includes a carrier gas pipeline. The carrier gas pipeline is connected to the gas inlet of the electrolyte storage device, and the carrier gas device is configured to introduce carrier gas into the electrolyte storage device.

[0009] An exhaust gas pretreatment device, the inlet of which is connected to the gas outlet. The exhaust gas pretreatment device is configured to pre-treat the gas flow discharged from the gas outlet.

[0010] In one of the embodiments, the exhaust gas pretreatment device includes a liquid storage device and a liquid blocking device;

[0011] The interior of the liquid storage device is configured to store cleaning liquid. The liquid storage device is provided with an inlet and an outlet. The inlet is connected to the gas outlet of the electrolyte storage device through a connecting pipe, and the end of the connecting pipe extends into the interior of the liquid storage device.

[0012] The liquid stopper is arranged inside the liquid storage device and located between the end of the connecting pipe and the outlet to separate the liquid level of the cleaning liquid from the outlet of the liquid storage device. The liquid stopper is configured to prevent liquid from passing through and allow gas to pass through;

[0013] The exhaust gas pretreatment device further includes a cooling pipe, a bubbler, and / or a temperature detector. The cooling pipe penetrates through the outer wall of the liquid storage device and extends into the interior of the liquid storage device. The interior of the cooling pipe is configured to store and circulate a coolant that can cool the cleaning liquid. The bubbler is connected to the end of the connecting pipe and is configured as a porous diffusion pipe for gas diffusion. The temperature detector is connected to the liquid storage device to monitor the temperature of the cleaning liquid.

[0014] In one embodiment, the exhaust gas pretreatment device includes a gas-liquid separation device. The inlet of the gas-liquid separation device is communicated with the gas outlet of the electrolyte storage device. The liquid outlet of the gas-liquid separation device is communicated with the interior of the electrolyte storage device, or the liquid outlet of the gas-liquid separation device is communicated with the outside.

[0015] In one embodiment, the exhaust gas pretreatment device includes an electrochemical hydrogen pump. The electrochemical hydrogen pump includes a power source and a proton exchange membrane, a catalytic reaction layer, a gas diffusion layer, an anode-side bipolar plate, and a cathode-side bipolar plate that are mutually attached. The proton exchange membrane is arranged between the anode-side bipolar plate and the cathode-side bipolar plate. The catalytic reaction layer is arranged between the proton exchange membrane and the anode-side bipolar plate and between the proton exchange membrane and the cathode-side bipolar plate. The gas diffusion layer is arranged between the catalytic reaction layer and the anode-side bipolar plate and between the catalytic reaction layer and the cathode-side bipolar plate. The anode-side bipolar plate is provided with a gas flow channel and an anode inlet and an anode outlet communicated with the gas flow channel. The cathode-side bipolar plate is provided with a cathode outlet. The power source is connected to the anode-side bipolar plate and the cathode-side bipolar plate to form an electric current loop;

[0016] The anode inlet is communicated with the gas outlet of the electrolyte storage device through an anode inlet pipeline. The anode outlet is communicated with the interior of the electrolyte storage device through an anode outlet pipeline. The cathode outlet is communicated with a cathode outlet pipeline.

[0017] In one embodiment, after the anode outlet pipeline and the carrier gas pipeline converge, they are communicated to the inlet of the electrolyte storage device;

[0018] The exhaust gas pretreatment device further includes a three-way valve, a first shunt pipe, and a second shunt pipe. One end of the first shunt pipe is connected to the carrier gas pipeline through the three-way valve, and the other end of the first shunt pipe is connected to the top space above the electrolyte liquid level in the electrolyte storage device. One end of the second shunt pipe is connected to the carrier gas pipeline through the three-way valve, and the other end of the second shunt pipe is immersed below the electrolyte liquid level in the electrolyte storage device.

[0019] In one embodiment, the exhaust gas pretreatment device further includes a first gas-liquid separator, a check valve, a stop valve, and a first liquid return pipeline. The first gas-liquid separator, the check valve, and the stop valve are arranged on the anode gas outlet pipeline, and the first gas-liquid separator is connected to the inside of the electrolyte storage device through the first liquid return pipeline; and / or

[0020] The exhaust gas pretreatment device further includes a second gas-liquid separator, a flow regulator, and a second liquid return pipeline. The second gas-liquid separator and the flow regulator are arranged on the cathode gas outlet pipeline, and the second gas-liquid separator is connected to the inside of the electrolyte storage device through the second liquid return pipeline; and / or

[0021] The exhaust gas treatment system further includes a gas storage tank, and the gas storage tank is arranged downstream of the exhaust gas pretreatment device; and / or

[0022] The electrochemcial hydrogen pump includes a voltage measurer and a current measurer. The voltage measurer is configured to measure the voltage of the current loop, and the current measurer is configured to measure the current of the current loop.

[0023] In one embodiment, the proton exchange membrane, the catalytic reaction layer, the gas diffusion layer, the anode-side bipolar plate, and the cathode-side bipolar plate are all arranged in a plate-like structure. The anode-side bipolar plate and the cathode-side bipolar plate are arranged opposite to each other, and the proton exchange membrane, the catalytic reaction layer, and the gas diffusion layer are stacked between the anode-side bipolar plate and the cathode-side bipolar plate; or

[0024] The proton exchange membrane, the catalytic reaction layer, the gas diffusion layer, the anode-side bipolar plate, and the cathode-side bipolar plate are all arranged in a tubular structure. The anode-side bipolar plate is sleeved outside the cathode-side bipolar plate, and the proton exchange membrane, the catalytic reaction layer, and the gas diffusion layer are sleeved along the radial direction between the anode-side bipolar plate and the cathode-side bipolar plate.

[0025] In one embodiment, the exhaust gas treatment system further includes a gas mixer, and the gas mixer is arranged downstream of the exhaust gas pretreatment device.

[0026] In one embodiment, the carrier gas device includes a carrier gas flow regulating valve, and the carrier gas flow regulating valve is disposed on the carrier gas pipeline;

[0027] The carrier gas device further includes a carrier gas filter, a carrier gas pressure regulator and / or a carrier gas pressure gauge. The carrier gas filter, the carrier gas pressure regulator and / or the carrier gas pressure gauge are disposed on the carrier gas pipeline, and the carrier gas filter, the carrier gas pressure regulator and / or the carrier gas pressure gauge are located upstream of the carrier gas flow regulating valve in the carrier gas delivery direction;

[0028] The exhaust gas treatment system further includes at least one first hydrogen concentration monitor, and the first hydrogen concentration monitor is connected to the electrolyte storage device and extends into the top space above the electrolyte liquid level in the electrolyte storage device.

[0029] In one embodiment, the exhaust gas treatment system further includes an exhaust gas measurement device and a control device. The exhaust gas measurement device is in communication with the outlet of the exhaust gas pretreatment device. The exhaust gas measurement device is configured to measure the hydrogen concentration, pressure, volume flow rate and temperature of the discharged gas so as to obtain the hydrogen discharge rate and the hydrogen discharge amount. The control device is electrically connected to the carrier gas device, the exhaust gas measurement device and the first hydrogen concentration monitor.

[0030] In one embodiment, the exhaust gas measurement device includes a concentration measurement component and a flow measurement component. The concentration measurement component is in communication with the outlet of the exhaust gas pretreatment device. The concentration measurement component is configured to measure the hydrogen concentration in the gas discharged from the outlet of the exhaust gas pretreatment device. The flow measurement component is in communication with the concentration measurement component. The flow measurement component is configured to measure the pressure, volume flow rate and temperature of the gas discharged from the outlet of the exhaust gas pretreatment device.

[0031] In one embodiment, the concentration measurement component includes a first measurement pipeline and a second hydrogen concentration monitor. The two ends of the first measurement pipeline are respectively in communication with the outlet of the exhaust gas pretreatment device and the concentration measurement component. The second hydrogen concentration monitor is disposed on the first measurement pipeline, and the second hydrogen concentration monitor is electrically connected to the control device; and / or

[0032] The flow measurement component includes a second measurement pipeline, an exhaust gas pressure monitor, an exhaust gas flow monitor and an exhaust gas temperature monitor. The second measurement pipeline is in communication with the concentration measurement component. The exhaust gas pressure monitor, the exhaust gas flow monitor and the exhaust gas temperature monitor are all disposed on the second measurement pipeline. The exhaust gas pressure monitor, the exhaust gas flow monitor and the exhaust gas temperature monitor are electrically connected to the control device.

[0033] An exhaust gas treatment method for a flow battery, implemented based on the above exhaust gas treatment system, the exhaust gas treatment method comprising the following steps:

[0034] Introduce carrier gas into the top space above the electrolyte liquid level in the electrolyte storage device through the carrier gas device to obtain a first mixed gas;

[0035] Pretreat the first mixed gas through the exhaust gas pretreatment device to obtain a second mixed gas; and

[0036] Measure the hydrogen concentration, pressure, volume flow rate and temperature in the second mixed gas through the exhaust gas measurement device, and calculate the hydrogen discharge rate and hydrogen discharge amount.

[0037] In one embodiment, the introducing carrier gas into the top space above the electrolyte liquid level in the electrolyte storage device through the carrier gas device includes:

[0038] Measure the hydrogen concentration in the top space above the electrolyte liquid level in the electrolyte storage device through the first hydrogen concentration monitor;

[0039] Judge whether the hydrogen concentration in the top space above the electrolyte liquid level in the electrolyte storage device exceeds a first threshold. If it exceeds the first threshold, open the carrier gas flow regulating valve to introduce carrier gas into the top space above the electrolyte liquid level in the electrolyte storage device to obtain a first mixed gas; and

[0040] Judge whether the hydrogen concentration in the top space above the electrolyte liquid level in the electrolyte storage device is lower than a second threshold. If it is lower than the second threshold, close the carrier gas flow regulating valve to stop introducing carrier gas into the top space above the electrolyte liquid level in the electrolyte storage device, where the second threshold is less than the first threshold.

[0041] In one embodiment, the measuring the hydrogen concentration, pressure, volume flow rate and temperature in the second mixed gas through the exhaust gas measurement device, and calculating the hydrogen discharge rate and hydrogen discharge amount includes:

[0042] Measure the hydrogen concentration in the second mixed gas through the second hydrogen concentration monitor;

[0043] Measure the pressure, volume flow rate and temperature of the second mixed gas through the exhaust gas pressure monitor, the exhaust gas flow monitor and the exhaust gas temperature monitor respectively;

[0044] Calculate the hydrogen discharge rate and hydrogen discharge amount based on the hydrogen concentration in the second mixed gas and the pressure, volume flow rate and temperature of the second mixed gas, and obtain the variation of the hydrogen discharge rate and hydrogen discharge amount with time;

[0045] Optionally, the exhaust gas treatment method further includes:

[0046] Calculating the power consumed by the flow battery due to hydrogen generation according to the hydrogen discharge amount; and / or

[0047] Changing at least one operating condition of the flow battery to obtain the hydrogen discharge rate, the hydrogen discharge amount, and their variations over time, and establishing the relationship between the operating condition and the hydrogen discharge rate and the hydrogen discharge amount, where the operating condition includes the charge-discharge condition of the flow battery, the operating condition of the electrolyte circulation system of the flow battery, and the operating condition of the reaction interface in the flow battery stack.

[0048] For the exhaust gas treatment system and the exhaust gas treatment method of the above flow battery, a carrier gas device is used to introduce a carrier gas into the top gas space of the storage cavity of the electrolyte storage device, so that the carrier gas is mixed with hydrogen to form a mixed gas. Thus, not only can the hydrogen concentration be regulated to maintain it within a suitable range, but also the hydrogen can be quickly discharged by regulating the carrier gas flow rate, improving the exhaust efficiency and effectively avoiding the safety risks caused by too high hydrogen concentration. Moreover, by using an exhaust gas pretreatment device to pretreat the mixed gas, functions such as removing trace salts, moisture and other impurities in the mixed gas, separating and purifying hydrogen, etc. can be realized, so as to facilitate the recycling of the discharged hydrogen. Description of the Drawings

[0049] Figure 1 It is a schematic diagram of the exhaust gas treatment system of the flow battery provided by an embodiment of the present application.

[0050] Figure 2 It is a schematic diagram of the exhaust gas treatment system of the flow battery provided by another embodiment of the present application.

[0051] Figure 3 It is a schematic diagram of the exhaust gas treatment system of the flow battery provided by still another embodiment of the present application.

[0052] Figure 4 is Figure 3 a schematic structural diagram of the exhaust gas pretreatment device in one embodiment.

[0053] Figure 5 is Figure 3 a schematic structural diagram of the exhaust gas pretreatment device in another embodiment.

[0054] Figure 6 is Figure 5 a schematic cross-sectional view of the exhaust gas pretreatment device.

[0055] Figure 7 It is a flowchart of the exhaust gas treatment method of the flow battery provided by an embodiment of the present application.

[0056] Figure 8 Flow chart of the exhaust gas treatment method for the flow battery provided in another embodiment of the present application.

[0057] Reference numerals in the accompanying drawings:

[0058] 10. Exhaust gas treatment system of the flow battery;

[0059] 100. Flow battery stack; 110. Anode side electrolyte inlet and outlet area; 120. Cathode side electrolyte inlet and outlet area;

[0060] 200. Electrolyte storage device; 210. Storage chamber; 220. Air inlet; 230. Air outlet; 240. Liquid return pipe; 250. Liquid supply pipe;

[0061] 300. Carrier gas device; 310. Carrier gas pipeline; 320. Carrier gas flow regulating valve; 330. Carrier gas filter; 340. Carrier gas pressure regulator; 350. Carrier gas pressure gauge;

[0062] 400. Exhaust gas pretreatment device; 410. Liquid reservoir; 411. Inlet; 412. Outlet; 420. Liquid block; 430. Connecting pipe; 440. Cooling pipe; 450. Bubbler; 460. Temperature measuring device;

[0063] 4100. Electrochemical hydrogen pump; 4110. Proton exchange membrane; 4120. Catalytic reaction layer; 4130. Gas diffusion layer; 4140. Anode side bipolar plate; 4141. Gas flow channel; 4142. Anode inlet; 4143. Anode outlet; 4150. Cathode side bipolar plate; 4151. Cathode outlet; 4160. Power supply; 4171. Voltage measuring device; 4172. Current measuring device; 4180. Seal; 4200. Anode inlet pipeline; 4300. Anode outlet pipeline; 4310. First gas-liquid separator; 4320. Check valve; 4330. Stop valve; 4340. First liquid return pipeline; 4400. Cathode outlet pipeline; 4410. Second gas-liquid separator; 4420. Flow regulator; 4430. Second liquid return pipeline; 4510. Three-way valve; 4520. First shunt pipe; 4530. Second shunt pipe;

[0064] 500. Exhaust gas measuring device; 510. Concentration measuring component; 511. First measuring pipeline; 513. Second hydrogen concentration monitor; 520. Flow measuring component; 521. Second measuring pipeline; 522. Exhaust gas pressure monitor; 523. Exhaust gas flow monitor; 524. Exhaust gas temperature monitor;

[0065] 600. Control device;

[0066] 700. First hydrogen concentration monitor;

[0067] 800, Gas mixer;

[0068] 910, Gas storage tank; 920, Gas release valve; 930, Hydrogen consumption area. Detailed implementation manners

[0069] To make the above objects, features, and advantages of the present application more apparent and understandable, the following will describe the detailed implementation manners of the present application with reference to the accompanying drawings. Many specific details are set forth in the following description to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0070] In the description of the present application, it should be understood that if terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or positional relationship indicated by these terms is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present application.

[0071] In addition, if terms such as "first" and "second" appear, these terms are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0072] In the present application, unless otherwise clearly specified and limited, if terms such as "installation", "connection", "connection", "fixation", "connection", etc. appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the connection inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0073] In this application, unless otherwise clearly specified and defined, if there is a description such as a first feature being "on" or "under" a second feature, its meaning can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature can be that the first feature is directly above or obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature can be that the first feature is directly below or obliquely below the second feature, or simply means that the horizontal height of the first feature is less than that of the second feature.

[0074] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or there can also be an intermediate element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intermediate element at the same time. If so, the terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used in this application are only for the purpose of illustration and do not represent the only implementation.

[0075] Referring to Figure 1 as shown, Figure 1 The figure shows a schematic diagram of the exhaust gas treatment system 10 of the flow battery in the embodiment of the present application. The exhaust gas treatment system 10 of the flow battery provided in the embodiment of the present application is used to treat the gas discharged from the flow battery. Among them, the flow battery includes a flow battery stack 100 and an electrolyte storage device 200. The exhaust gas treatment system 10 of the flow battery includes a carrier gas device 300 and an exhaust gas pretreatment device 400.

[0076] The flow battery stack 100 is the main place where the electrochemical reaction occurs. The flow battery stack 100 has an anode-side electrolyte inlet and outlet area 110 and a cathode-side electrolyte inlet and outlet area 120. In each flow battery unit in the flow battery stack 100, there are reaction interfaces and reaction chambers formed by positive and negative electrodes and related electrolytes. The spatial division of the electrolyte inlet and outlet areas on the cathode and anode sides of the stack is different from that of the reaction chambers on the cathode and anode sides in the stack. Only the electrolyte inlet and outlet areas on the cathode and anode sides are shown in the figure. Under the action of an external potential, the electrolyte on the anode side and the electrolyte on the cathode side each undergo an electrochemical reaction and a charge and discharge process in the reaction chambers in the flow battery stack 100, and at the same time, a side reaction of generating hydrogen may occur. Only the electrolyte circulation mode on the anode side is shown in the figure, and the corresponding exhaust gas treatment system 10 only shows the part for treating and measuring the hydrogen discharged from the anode side. It should be understood that the working principle of the exhaust gas treatment system on the cathode side is the same as that of the exhaust gas treatment system on the anode side, and will not be described in detail herein.

[0077] The electrolyte storage device 200 on the anode side is used to provide a continuous and stable electrolyte fluid for the flow battery stack 100. The interior of the electrolyte storage device 200 has a storage chamber 210, in which the electrolyte is stored. The electrolyte flows into and out of the storage chamber 210 of the electrolyte storage device 200, while the gas flows into and out of the top gas space in the storage chamber 210. The electrolyte storage device 200 is provided with a liquid inlet, a liquid outlet, an air inlet 220 and an air outlet 230. The storage chamber 210 of the electrolyte storage device 200 is communicated with the anode side of the flow battery stack 100 through the liquid inlet and the liquid outlet to form an electrolyte circuit. The electrolyte storage device 200 is provided with an air inlet 220 and an air outlet 230 that are communicated with the top gas space in the storage chamber 210. For example, the electrolyte storage device 200 can be an electrolyte storage tank. The liquid inlet of the electrolyte storage tank is communicated with the anode side of the flow battery stack 100 through a return pipe 240, and the liquid outlet of the electrolyte storage tank is communicated with the anode side of the flow battery stack 100 through a liquid delivery pipe 250. A circulation pump is arranged on the liquid delivery pipe 250 to realize the circulation of the electrolyte, thereby forming an electrolyte circuit. Specifically, the electrolyte in the electrolyte storage tank flows out from the liquid outlet at the bottom of the tank and enters the reaction chamber on the anode side of the flow battery stack 100 through the liquid delivery pipe 250 and the circulation pump. Hydrogen is mainly generated inside the flow battery stack 100. The generated hydrogen is carried by the electrolyte and flows back to the electrolyte storage tank through the return pipe 240 and the liquid inlet, and gas-liquid separation is completed at the end of the return pipe 240. The hydrogen bubbles diffuse into the gas space above the liquid level in the electrolyte storage tank. The top of the electrolyte storage tank is provided with a pressure relief valve, an air inlet 220 and an air outlet 230. The air inlet 220 is used to introduce carrier gas into the top gas space in the electrolyte storage tank, and the air outlet 230 is used to discharge the mixed gas in the top gas space in the electrolyte storage tank, thereby discharging hydrogen. It should be understood that the operating principle of the electrolyte storage device on the cathode side is the same as that of the electrolyte storage device 200 on the anode side, and will not be described in detail herein.

[0078] The carrier gas device 300 includes a carrier gas pipeline 310. The carrier gas pipeline 310 is communicated with the air inlet 220 of the electrolyte storage device 200. The carrier gas device 300 is configured to introduce carrier gas into the top gas space in the storage chamber 210. Exemplarily, the carrier gas flow is preferably an inert compressed gas such as high-purity nitrogen. In some cases, compressed air that has been deoiled, dehydrated and purified can also be selected. The carrier gas is transported into the top gas space of the storage chamber 210, so that the carrier gas is preliminarily mixed with gases such as hydrogen in the top gas space of the storage chamber 210. In this way, a stable mixed gas containing hydrogen with a certain concentration and pressure can be formed, which is beneficial to quickly discharging hydrogen, and is also beneficial to functions such as hydrogen treatment, quantitative measurement of hydrogen concentration and flow rate in subsequent processes.

[0079] The inlet of the exhaust gas pretreatment device 400 is in communication with the outlet 230. The exhaust gas pretreatment device 400 is configured to preprocess the gas flow discharged from the outlet 230. The pretreatment may specifically include cooling the gas flow, removing impurities, gas-liquid separation, purification, etc. Exemplarily, the exhaust gas pretreatment device 400 may be configured to remove salts and moisture from the gas flow discharged from the outlet 230 to avoid interference of the contained salts and moisture with the measurement results. It should be noted that the above salts and moisture come from the trace salts and moisture carried out from the electrolyte when hydrogen passes through the electrolyte and the trace water vapor generated by evaporation. In some embodiments, as Figure 1 shown, the exhaust gas pretreatment device 400 includes a gas-liquid separation device. The gas-liquid separation device may be optionally a mechanical or condensing gas-liquid separator. The inlet of the gas-liquid separation device is in communication with the outlet 230 of the electrolyte storage device 200, and the liquid outlet of the gas-liquid separation device is in communication with the interior of the electrolyte storage device 200, or the liquid outlet of the gas-liquid separation device is in communication with the outside. Exemplarily, the exhaust gas pretreatment device 400 may be a condenser, and the condenser is used to cool the gas flow discharged from the electrolyte storage device 200 to remove the trace salts and water vapor in the gas flow. For example, the condenser may be a coil type or shell-and-tube type condenser. The tube side of the condenser is in communication with the outlet 230 of the electrolyte storage device 200, and the shell side of the condenser is in communication with a cooling medium, such as chilled water, and the chilled water on the shell side is used to cool the gas flow in the tube side. Specifically, when a carrier gas is introduced into the top gas space of the storage cavity 210, under the action of the carrier gas, the high-temperature and high-humidity mixed gas in the top gas space of the storage cavity 210 flows into the condenser from the outlet 230. The shell side of the condenser is the chilled water circulation. When the mixed gas flows through the tube side of the condenser, it is cooled and the flow rate is reduced, so that the trace salts and water vapor carried in the mixed gas will be condensed into a liquid, and the condensate flows back to the storage cavity 210 through an independent pipeline or the condensate is directly discharged out of the system, thereby removing the trace salts and moisture from the mixed gas flowing out of the condenser.

[0080] The exhaust gas treatment system 10 of the above flow battery uses the carrier gas device 300 to introduce a carrier gas into the top gas space of the electrolyte storage device 200, so that the carrier gas is mixed with hydrogen to form a mixed gas. Thus, the hydrogen concentration can be regulated to maintain the hydrogen concentration within a suitable range, and the hydrogen can be quickly discharged by regulating the carrier gas flow rate, improving the exhaust efficiency and effectively avoiding the safety risks brought by too high hydrogen concentration. Moreover, using the exhaust gas pretreatment device 400 to preprocess the mixed gas can achieve functions such as removing trace salts and moisture and other impurities from the mixed gas and purifying hydrogen, so as to facilitate the safe discharge or further recycling of the discharged hydrogen.

[0081] Further, continue to refer to Figure 1As shown, the exhaust gas treatment system 10 of the flow battery provided by the embodiment of the present application further includes an exhaust gas measuring device 500 and a control device 600. The control device 600 is electrically connected to the carrier gas device 300 and the exhaust gas measuring device 500. This exhaust gas treatment system 10 can stably, accurately, and reliably measure the hydrogen concentration, pressure, volume flow rate, and temperature of the gas discharged from the flow battery, so as to obtain the hydrogen discharge rate and the hydrogen discharge amount.

[0082] Specifically, the exhaust gas measuring device 500 is communicated with the outlet of the exhaust gas pretreatment device 400. The exhaust gas measuring device 500 is configured to measure the hydrogen concentration, pressure, volume flow rate, and temperature of the discharged gas, so as to obtain the hydrogen discharge rate and the hydrogen discharge amount. Exemplarily, the control device 600 can adopt a programmable logic controller (PLC) or a distributed control system (DCS). The control device 600 is used to control the carrier gas flow rate of the carrier gas device 300, read the measured values of the exhaust gas measuring device 500, and perform calculations to obtain the hydrogen discharge rate and the hydrogen discharge amount.

[0083] Through the above structural design, the exhaust gas pretreatment device 400 is used to remove trace salts and moisture in the mixed gas, so that it can not only avoid the influence of impurities such as salts and moisture on the measurement results of hydrogen, improve the measurement accuracy, but also avoid the corrosion of subsequent exhaust gas measuring device 500 by impurities such as salts and moisture, resulting in the influence on the reliability and service life of the exhaust gas measuring device 500.

[0084] Therefore, the exhaust gas treatment system 10 of the embodiment of the present application can measure the hydrogen concentration, pressure, volume flow rate, and temperature of the gas discharged from the flow battery in real time and accurately, so as to obtain the hydrogen discharge rate and the hydrogen discharge amount, and at the same time safely and reasonably discharge the generated hydrogen. And, based on the measurement accuracy of the hydrogen discharge rate and the hydrogen discharge amount, the factors affecting the hydrogen discharge rate and the hydrogen discharge amount and the relationship and regularity between each factor and the hydrogen discharge rate and the hydrogen discharge amount can be found in combination with the charge and discharge process of the flow battery, which helps to select appropriate flow battery process parameters, and then prevent or reduce the generation of hydrogen by regulating appropriate working conditions, reduce the electric energy consumed due to the generation of hydrogen and the resulting safety problems, and is beneficial to improving the charge and discharge efficiency of the flow battery and reducing the operation safety risk.

[0085] In some embodiments, the exhaust gas treatment system further includes a gas mixer 800, which is disposed downstream of the exhaust gas pretreatment device 400. Herein, the "downstream" refers to the direction of gas flow, where the gas inlet is upstream and the gas outlet is downstream. Specifically, the gas mixer 800 is disposed between the outlet of the exhaust gas pretreatment device 400 and the exhaust gas measuring device 500. For example, the gas mixer 800 can be a static mixer, and the gas mixer 800 is disposed between the condenser and the exhaust gas measuring device 500. The hydrogen-containing mixed gas flow flowing out from the condenser enters the gas mixer 800, enabling the hydrogen-containing mixed gas flow to be fully mixed to obtain a mixed gas flow with a uniform hydrogen concentration, so as to accurately measure the hydrogen concentration of the mixed gas flow through the exhaust gas measuring device 500.

[0086] Refer to Figure 1 As shown, in some embodiments, the carrier gas device 300 includes a carrier gas pipeline 310 and a carrier gas flow regulating valve 320. The carrier gas pipeline 310 is communicated with the air inlet 220 of the electrolyte storage device 200. The carrier gas flow regulating valve 320 is disposed on the carrier gas pipeline 310 and is electrically connected to the control device 600. Specifically, one end of the carrier gas pipeline 310 is communicated with a gas source. For example, the gas source can be a high-purity compressed nitrogen tank. The other end of the carrier gas pipeline 310 is communicated with the air inlet 220 of the electrolyte storage device 200, thereby introducing a carrier gas into the top gas space in the storage chamber 210. The carrier gas flow regulating valve 320 is controlled by the control device 600 to control the carrier gas flow rate flowing through the carrier gas pipeline 310 within a suitable range.

[0087] Further, in some embodiments, the carrier gas device 300 further includes a carrier gas filter 330, a carrier gas pressure regulator 340, and / or a carrier gas pressure gauge 350 disposed on the carrier gas pipeline 310. The carrier gas filter 330, the carrier gas pressure regulator 340, and / or the carrier gas pressure gauge 350 are located upstream of the carrier gas flow regulating valve 320 in the carrier gas conveying direction. Exemplarily, the carrier gas filter 330, the carrier gas pressure regulator 340, the carrier gas pressure gauge 350, and / or the carrier gas flow regulating valve 320 are sequentially arranged along the carrier gas conveying direction. Thus, the carrier gas first passes through the carrier gas filter 330 to remove solid particulate impurities in the carrier gas; then passes through the carrier gas pressure regulator 340 to regulate the pressure of the carrier gas. For example, the carrier gas pressure regulator 340 can be set with a pressure reducing function; then passes through the carrier gas pressure gauge 350 to detect the pressure of the regulated carrier gas to ensure that the carrier gas is reduced to a suitable pressure. For example, the carrier gas pressure gauge 350 can be a pressure gauge; then passes through the carrier gas flow regulating valve 320 to regulate the carrier gas flow rate to form a carrier gas flow with a required flow rate. This carrier gas flow is finally conveyed into the top gas space in the storage chamber 210 and is fully mixed with gases such as hydrogen in the top gas space in the storage chamber 210 to form a hydrogen-containing mixed gas.

[0088] Since the electrolyte storage device 200 is generally in a closed space, if the hydrogen concentration in the top gas space of the storage chamber 210 is too high, there may be risks such as explosion. Therefore, in some embodiments, the exhaust gas treatment system 10 further includes at least one first hydrogen concentration monitor 700. The first hydrogen concentration monitor 700 is connected to the electrolyte storage device 200 and extends into the top gas space above the electrolyte liquid level in the storage chamber 210. The first hydrogen concentration monitor 700 is electrically connected to the control device 600. Exemplarily, the first hydrogen concentration monitor 700 may be a hydrogen concentration detector, a hydrogen concentration transmitter, etc. The first hydrogen concentration monitor 700 is used to detect the hydrogen concentration in the top gas space of the storage chamber 210 of the electrolyte storage device 200 in real time, and transmit the detected value to the control device 600, so that the opening degree of the carrier gas flow regulating valve 320 can be adjusted in real time according to the hydrogen concentration to regulate the carrier gas flow, thereby adjusting the hydrogen concentration in the hydrogen-containing mixed gas in the top gas space of the storage chamber 210, and further avoiding the problem of too high hydrogen concentration. And when the first hydrogen concentration monitor 700 detects that the hydrogen concentration in the top gas space of the storage chamber 210 of the electrolyte storage device 200 is relatively low, and at this time the hydrogen concentration is lower than the measurable range of the exhaust gas measurement device 500, the carrier gas flow regulating valve 320 can be shut down to stop introducing the carrier gas into the electrolyte storage device 200, and after stopping the introduction of the carrier gas, the measurement process can still continue.

[0089] In some embodiments, the exhaust gas measurement device 500 includes a concentration measurement component 510 and a flow measurement component 520. The concentration measurement component 510 is communicated with the outlet of the exhaust gas pretreatment device 400. The concentration measurement component 510 is configured to measure the hydrogen concentration in the gas discharged from the outlet of the exhaust gas pretreatment device 400. The flow measurement component 520 is communicated with the concentration measurement component 510. The flow measurement component 520 is configured to measure the gas pressure, volume flow rate and temperature of the gas discharged from the outlet of the exhaust gas pretreatment device 400. The hydrogen concentration in the mixed gas discharged from the outlet of the exhaust gas pretreatment device 400 and the pressure, volume flow rate and temperature of the mixed gas can be measured respectively by the concentration measurement component 510 and the flow measurement component 520, so that the hydrogen discharge rate and hydrogen discharge amount can be calculated.

[0090] Refer to Figure 1As shown, in some embodiments, the concentration measurement assembly 510 includes a first measurement pipeline 511 and a second hydrogen concentration monitor 513. The two ends of the first measurement pipeline 511 are respectively communicated with the outlet of the exhaust gas pretreatment device 400. The second hydrogen concentration monitor 513 is arranged on the first measurement pipeline 511, and the second hydrogen concentration monitor 513 is electrically connected to the control device 600. For example, the second hydrogen concentration monitor 513 can be a hydrogen concentration analyzer. The hydrogen-containing mixed gas flow flowing out of the exhaust gas pretreatment device 400 enters the first measurement pipeline 511, and then the hydrogen concentration of the mixed gas flow can be accurately measured by passing through the second hydrogen concentration monitor 513.

[0091] It can be understood that under continuous chemical conditions, the second hydrogen concentration monitor 513 can measure the instantaneous hydrogen concentration of the mixed gas flow and transmit the measured value of the instantaneous hydrogen concentration to the control device 600 in real time for calculation and processing. Moreover, the control device 600 can adjust the opening degree of the carrier gas flow regulating valve 320 according to the concentration value measured by the second hydrogen concentration monitor 513 to regulate the carrier gas flow, so as to keep the instantaneous hydrogen concentration within a suitable measurement range, ensure the system safety and the accuracy of the measurement result, and facilitate the safe and accurate measurement of the hydrogen concentration in the mixed gas flow.

[0092] Continue to refer to Figure 1 As shown, in some embodiments, the flow measurement assembly 520 includes a second measurement pipeline 521, an exhaust gas pressure monitor 522, an exhaust gas flow monitor 523 and an exhaust gas temperature monitor 524. The second measurement pipeline 521 is communicated with the concentration measurement assembly 510. The exhaust gas pressure monitor 522, the exhaust gas flow monitor 523 and the exhaust gas temperature monitor 524 are all arranged on the second measurement pipeline 521, and the exhaust gas pressure monitor 522, the exhaust gas flow monitor 523 and the exhaust gas temperature monitor 524 are electrically connected to the control device 600. For example, the exhaust gas pressure monitor 522 can be a pressure transmitter, a pressure gauge, etc., the exhaust gas flow monitor 523 can be a flow transmitter, a flow meter, etc., and the exhaust gas temperature monitor 524 can be a temperature transmitter, a thermocouple, a thermal resistor, etc. Specifically, the mixed gas flow flowing out of the concentration measurement assembly 510 sequentially flows through the exhaust gas pressure monitor 522, the exhaust gas flow monitor 523 and the exhaust gas temperature monitor 524, so as to respectively measure the pressure, volumetric flow and temperature values of the mixed gas flow in real time, and transmit these measured values to the control device 600 in real time. Finally, the mixed gas flow containing hydrogen is discharged to a safe place through the second measurement pipeline 521.

[0093] Thus, after the control device 600 obtains the instantaneous pressure, instantaneous volume flow rate, and instantaneous temperature values of the mixed gas stream in real time, based on the instantaneous pressure, instantaneous volume flow rate, instantaneous temperature, and the instantaneous hydrogen concentration measured by the concentration measurement component 510, the instantaneous flow rate of hydrogen under standard conditions (Standard State of Gas, which refers to the state of a gas under specific temperature and pressure conditions) can be calculated. Furthermore, the instantaneous value of the amount of substance of hydrogen can be calculated. By integrating the instantaneous value of the amount of substance of hydrogen with the time element, the total amount of hydrogen discharged within a certain period can be calculated (the specific calculation process can be found in the calculation steps described later).

[0094] Refer to Figure 2 As shown, which shows a schematic diagram of the exhaust gas treatment system 10 of a flow battery in another embodiment of the present application. Specifically, the exhaust gas pretreatment device 400 includes a liquid storage device 410 and a liquid blocking device 420; the interior of the liquid storage device 410 is configured to store cleaning liquid. The liquid storage device 410 is provided with an inlet 411 and an outlet 412. The inlet 411 of the liquid storage device 410 is connected to the gas outlet 230 of the electrolyte storage device 200 through a connecting pipe 430. The end of the connecting pipe 430 extends below the liquid level of the cleaning liquid stored in the liquid storage device 410. The outlet 412 of the liquid storage device 410 is connected to the exhaust gas measurement device 500; the liquid blocking device 420 is arranged inside the liquid storage device 410 and is located between the end of the connecting pipe 430 and the outlet 412. The amount of cleaning liquid used satisfies that the liquid level of the cleaning liquid is between the end of the connecting pipe 430 and the liquid blocking device 420.

[0095] For example, the liquid storage device 410 can be a deionized water tank, and the interior of the deionized water tank is filled with an appropriate volume of deionized water as the cleaning liquid. The liquid blocking device 420 is arranged inside the liquid storage device 410. The liquid blocking device 420 separates the liquid level of the cleaning liquid from the outlet 412 of the liquid storage device 410. For example, the liquid blocking device 420 can be a microporous hydrophobic membrane, a PTFE membrane, etc. The liquid blocking device 420 is used to prevent liquid droplets from entering the top space of the liquid storage device 410 and allow gas to pass through. Specifically, under the push of the carrier gas flow, the high-temperature and high-humidity mixed gas in the gas space at the top of the storage chamber 210 of the electrolyte storage device 200 is transported from the connecting pipe 430 and the inlet 411 into the deionized water in the deionized water tank, thereby cleaning the trace salts in the mixed gas stream flowing out of the gas space at the top of the storage chamber 210 of the electrolyte storage device 200. Then, after the mixed gas removes the liquid droplets through the liquid blocking device 420, it flows out from the outlet 412 at the top of the deionized water tank. Thus, the salts and moisture in the mixed gas can be effectively removed.

[0096] Continue to refer to Figure 2As shown, in some embodiments, the exhaust gas pretreatment device 400 further includes a cooling pipe 440, which penetrates through the outer wall of the liquid storage device 410 and extends into the cleaning liquid inside the liquid storage device 410. For example, at least part of the structure of the cooling pipe 440 is disposed inside the liquid storage device 410, and both ends of the cooling pipe 440 are located outside the liquid storage device 410. The inside of the cooling pipe 440 stores and circulates chilled water, and the chilled water and the cooling pipe 440 cooperate to cool the cleaning liquid inside the liquid storage device 410, so that the cleaning liquid maintains a relatively low temperature. Thus, the high-temperature and high-humidity mixed gas in the gas space at the top of the storage chamber 210 of the electrolyte storage device 200 is cleaned with the low-temperature cleaning liquid, so that the temperature of the mixed gas can be quickly reduced, thereby improving the safety of gas transportation. At the same time, the water vapor partial pressure in the subsequent air flow is reduced, which is conducive to further reducing the moisture content in the mixed gas.

[0097] Optionally, the exhaust gas pretreatment device 400 further includes a bubbler 450, and the bubbler 450 is connected to the end of the connecting pipe 430 that extends below the liquid level of the cleaning liquid. For example, the bubbler 450 can be set as a porous diffusion pipe, and the porous diffusion pipe is used for gas diffusion. The porous diffusion pipe is made of porous materials such as ceramsite and coarse porcelain mixed with adhesives such as phenolic resin and sintered into a porous diffusion pipe at high temperature. The porous diffusion pipe has the ability to resist strong acid and alkali corrosion. The porosity of the porous diffusion pipe is related to the composition of the electrolyte, and it should be ensured that the liquid-gas mixture will not be blocked when flowing through the porous diffusion pipe. Thus, when the mixed gas enters the cleaning liquid through the bubbler 450, uniform fine bubbles will be generated, and the mixed gas will be dispersed into a large number of tiny bubbles and sent into the cleaning liquid, so as to fully clean the mixed gas and further improve the removal effect of the salt entrained in the mixed gas.

[0098] Optionally, the exhaust gas pretreatment device 400 further includes a temperature detector 460, and the temperature detector 460 is connected to the liquid storage device 410 to monitor the temperature of the cleaning liquid. For example, the temperature detector 460 can be a bimetallic thermometer, and the bimetallic thermometer is used to monitor the temperature of the cleaning liquid to facilitate reasonable regulation of the temperature of the cleaning liquid.

[0099] Refer to Figures 3 to 6As shown, a schematic diagram of the exhaust gas treatment system 10 of the flow battery in another embodiment of the present application is shown. Specifically, the exhaust gas pretreatment device 400 includes an electrochemical hydrogen pump 4100. The electrochemical hydrogen pump 4100 includes a power source 4160 and a proton exchange membrane 4110, a catalytic reaction layer 4120, a gas diffusion layer 4130, an anode-side bipolar plate 4140, and a cathode-side bipolar plate 4150 that are closely attached to each other. The proton exchange membrane 4110 is disposed between the anode-side bipolar plate 4140 and the cathode-side bipolar plate 4150, and the proton exchange membrane 4110 is used for protons to migrate from the anode side to the cathode side. Catalytic reaction layers 4120 and gas diffusion layers 4130 are disposed on both the anode side and the cathode side of the electrochemical hydrogen pump 4100. The catalytic reaction layer 4120 on the anode side is disposed between the proton exchange membrane 4110 and the anode-side bipolar plate 4140, and the gas diffusion layer 4130 on the anode side is disposed between the catalytic reaction layer 4120 and the anode-side bipolar plate 4140. The catalytic reaction layer 4120 on the cathode side is disposed between the proton exchange membrane 4110 and the cathode-side bipolar plate 4150, and the gas diffusion layer 4130 on the cathode side is disposed between the catalytic reaction layer 4120 and the cathode-side bipolar plate 4150. The gas diffusion layer 4130 allows the reactant gas to diffuse to the catalytic reaction layer 4120, and the catalytic reaction layer 4120 is used to increase the reaction rate. The anode-side bipolar plate 4140 is provided with a gas flow channel 4141 and an anode inlet 4142 and an anode outlet 4143 that communicate with the gas flow channel 4141. The cathode-side bipolar plate 4150 is provided with a cathode outlet 4151. The power source 4160 is connected to the anode-side bipolar plate 4140 and the cathode-side bipolar plate 4150 to form an electric current loop, which is used to provide the electric energy required during the exhaust gas treatment process. The anode inlet 4142 is connected to the gas outlet 230 of the electrolyte storage device 200 through the anode inlet pipe 4200. The anode outlet 4143 is connected to the inside of the electrolyte storage device 200 through the anode outlet pipe 4300. The cathode outlet 4151 is connected to the exhaust gas measurement device 500 through the cathode outlet pipe 4400.

[0100] When the mixed gas in the gas space at the top of the storage chamber 210 of the electrolyte storage device 200 enters the electrochemical hydrogen pump 4100 through the anode inlet pipe 4200, hydrogen is oxidized to protons (H + ) and electrons (e - ) on the anode side: H2 → 2H + + 2e - . The protons migrate to the cathode side through the proton exchange membrane 4110 and are reduced to hydrogen on the cathode side: 2H + + 2e - → H2. Thus, through the above reaction, hydrogen can be separated from the mixed gas and discharged in a high-purity form on the cathode side, thereby realizing the separation and purification of hydrogen, and further effectively recycling the hydrogen generated by the flow battery.

[0101] Optionally, referring to Figure 4 As shown, in some embodiments, the proton exchange membrane 4110, the catalytic reaction layer 4120, the gas diffusion layer 4130, the anode-side bipolar plate 4140, and the cathode-side bipolar plate 4150 of the electrochemical hydrogen pump 4100 are all arranged in a plate-like structure and are closely attached to each other. The anode-side bipolar plate 4140 and the cathode-side bipolar plate 4150 are arranged opposite to each other. The proton exchange membrane 4110, the catalytic reaction layer 4120, and the gas diffusion layer 4130 are stacked between the anode-side bipolar plate 4140 and the cathode-side bipolar plate 4150. At the same time, a seal 4180, such as a sealing strip, is arranged between the anode-side bipolar plate 4140 and the cathode-side bipolar plate 4150 to avoid gas leakage. Thus, the electrochemical hydrogen pump 4100 is arranged in a plate-like structure, with low resistivity and low power consumption.

[0102] Optionally, referring to Figure 5 and Figure 6 As shown, in some embodiments, the proton exchange membrane 4110, the catalytic reaction layer 4120, the gas diffusion layer 4130, the anode-side bipolar plate 4140, and the cathode-side bipolar plate 4150 of the electrochemical hydrogen pump 4100 are all arranged in a tubular structure and are closely attached to each other. The anode-side bipolar plate 4140 is sleeved outside the cathode-side bipolar plate. The proton exchange membrane 4110, the catalytic reaction layer 4120, and the gas diffusion layer 4130 are sleeved along the radial direction between the anode-side bipolar plate 4140 and the cathode-side bipolar plate 4150. Thus, the electrochemical hydrogen pump 4100 is arranged in a tubular structure, making the overall structural strength of the electrochemical hydrogen pump 4100 high, and the sealing design can be reduced, and the gas transportation performance is better.

[0103] It should be understood that the structure shown in the drawings is only the minimum unit structure component of the electrochemical hydrogen pump 4100. In actual applications, according to the amount of hydrogen to be processed, multiple such minimum unit structure components can be assembled and used. For example, an electrochemical hydrogen pump 4100 group assembled from multiple plate-like structure electrochemical hydrogen pumps 4100 or tubular structure electrochemical hydrogen pumps 4100 can be obtained. The relevant structures are more modular and have a stronger ability to process hydrogen mixed gas, so as to meet the industrial requirements such as separation, purification, and storage of a large amount of hydrogen that may be discharged from a liquid flow battery independent energy storage power station. And, due to the hydrogen separation and purification function of the electrochemical hydrogen pump 4100, the hydrogen discharged by the electrochemical hydrogen pump 4100 has a higher purity. Therefore, in this embodiment, there is no need to set a gas mixer 800 to ensure uniform hydrogen dispersion, making the structure of the exhaust gas treatment system more compact.

[0104] Referring to Figure 3As shown, in some embodiments, after the anode gas outlet pipeline 4300 converges with the carrier gas pipeline 310, it is connected to the air inlet 220 of the electrolyte storage device 200. Specifically, one end of the anode gas outlet pipeline 4300 is connected to the anode outlet 4143, and the other end of the anode gas outlet pipeline 4300 is connected to the carrier gas pipeline 310. The anode gas outlet pipeline 4300 helps to send back part of the unreacted hydrogen mixture to the electrolyte storage device 200 to avoid hydrogen loss. At the same time, the anode gas outlet pipeline 4300 can timely discharge part of the saturated moisture (containing hydrogen) in the electrochemical hydrogen pump 4100, avoiding the occurrence of an overflow phenomenon on the anode side and even in the entire electrochemical hydrogen pump 4100, which may cause the gas flow channel 4141 to be blocked by water.

[0105] It should be noted that due to the need for heating and heat preservation of the electrolyte in the electrolyte storage device 200, the humidity of the gas space at the top inside the storage cavity 210 of the electrolyte storage device 200 is very high. Moreover, during the process of the electrolyte reflux (carrying hydrogen) of the flow battery stack 100, the corresponding liquid return pipe 240 will extend into the electrolyte liquid surface, resulting in hydrogen usually generating bubbles under the electrolyte liquid surface and continuously accumulating in the gas space at the top inside the storage cavity 210. Therefore, the gas mixture discharged from the electrolyte storage device 200 generally contains hydrogen, air, carrier gas, water vapor, and components of the electrolyte, that is, the gas processed before the electrochemical hydrogen pump 4100 should be a low-concentration and low-pressure hydrogen mixture. If the water content in the above gas mixture is too high, it may cause an overflow in the catalytic reaction layer 4120 and the gas diffusion layer 4130 on the anode side, resulting in the phenomenon that the gas flow channel 4141 is blocked by water; if the water content in the above gas mixture is too low, it will cause the water content of the proton exchange membrane 4110 to decrease, reducing the proton conductivity of the proton exchange membrane 4110. Therefore, if the proton exchange membrane 4110 cannot be maintained within a suitable water content range, it will affect the hydrogen separation and purification work efficiency of the electrochemical hydrogen pump 4100, and be accompanied by an increase in the resistance and voltage drop of the proton exchange membrane 4110, and an increase in the energy loss required for related electrochemical reactions.

[0106] It should also be noted that the carrier gas should be selected as a high-purity inert compressed gas or compressed air that has been dried and purified, so as to avoid side reactions between the carrier gas and the electrolyte during the exhaust process.

[0107] Continue to refer to Figure 3As shown, the exhaust gas pretreatment device 400 of this embodiment further includes a three-way valve 4510, a first shunt pipe 4520, and a second shunt pipe 4530. One end of the first shunt pipe 4520 is connected to the carrier gas pipeline 310 through the three-way valve 4510, and the other end of the first shunt pipe 4520 is connected to the top space above the electrolyte liquid level in the electrolyte storage device 200, thereby forming a first branch a communicating with the carrier gas pipeline 310. One end of the second shunt pipe 4530 is connected to the carrier gas pipeline 310 through the three-way valve 4510, and the other end of the second shunt pipe 4530 is immersed below the electrolyte liquid level in the electrolyte storage device 200, thereby forming a first branch b communicating with the carrier gas pipeline 310. Specifically, generally, the gas mixture passing through the first branch a can meet the requirement of the proton exchange membrane 4110 of the electrochemical hydrogen pump 4100 for water content. If in actual operation, the gas mixture passing through the first branch a still cannot meet the requirement of the proton exchange membrane 4110 of the electrochemical hydrogen pump 4100 for water content, then the second branch b can be partially opened (by controlling the three-way valve 4510 to adjust the duty ratio of the opening of the first branch a and the second branch b or the opening ratio of the first branch a and the second branch b) to increase the water content of the gas mixture entering the electrochemical hydrogen pump 4100. Of course, the second branch b can also work independently, which can enable the proton exchange membrane 4110 of the electrochemical hydrogen pump 4100 to quickly reach and maintain a certain water content, facilitating the normal operation of the electrochemical hydrogen pump 4100. Thus, through the above method, the proton exchange membrane 4110 can always be maintained in the required wet state, so that the hydrogen separation and purification working efficiency of the electrochemical hydrogen pump 4100 can be maintained at the desired level.

[0108] In some embodiments, the exhaust gas pretreatment device 400 further includes a first gas-liquid separator 4310, a check valve 4320, a stop valve 4330, and a first liquid return pipeline 4340. The first gas-liquid separator 4310, the check valve 4320, and the stop valve 4330 are arranged on the anode gas outlet pipeline 4300. The check valve 4320 is used to prevent gas backflow, and the stop valve 4330 controls the on-off of the anode gas outlet pipeline 4300. The first gas-liquid separator 4310 is internally connected to the electrolyte storage device 200 through the first liquid return pipeline 4340. Exemplarily, the first gas-liquid separator 4310 can be a mechanical or condensing gas-liquid separator. The first gas-liquid separator 4310 is used to separate the water vapor part in the hydrogen mixture and send the separated liquid phase part back into the electrolyte storage device 200 through the first liquid return pipeline 4340. It should be understood that in other alternative embodiments, the liquid phase part separated by the first gas-liquid separator 4310 can also be directly discharged outside the exhaust gas treatment system.

[0109] In some embodiments, the exhaust gas pretreatment device 400 further includes a second gas-liquid separator 4410, a flow regulator 4420, and a second liquid return line 4430. The second gas-liquid separator 4410 and the flow regulator 4420 are disposed on the cathode gas outlet line 4400, and the second gas-liquid separator 4410 is internally communicated with the electrolyte storage device 200 through the second liquid return line 4430. Exemplarily, the second gas-liquid separator 4410 may be a mechanical or condensing gas-liquid separator. The second gas-liquid separator 4410 is used to separate the water vapor portion in the hydrogen mixture, which helps remove the water vapor in the purified hydrogen, improve the hydrogen purity, and at the same time send the separated liquid phase portion back into the electrolyte storage device 200 through the second liquid return line 4430. It should be understood that in other alternative embodiments, the liquid phase portion separated by the second gas-liquid separator 4410 may also be directly discharged outside the exhaust gas treatment system. Exemplarily, the flow regulator 4420 includes a valve structure for regulating the flow rate such as a back pressure valve or an adjustment valve, so as to regulate the flow rate and increase the hydrogen pressure generated on the cathode side, so as to store the high-purity hydrogen in a high-pressure state in the subsequent gas storage tank 910.

[0110] Thus, in the exhaust gas treatment system 10 of the flow battery, when the gas mixture containing the electrolyte component enters the electrochemical hydrogen pump 4100, part of the electrolyte will remain in the electrochemical hydrogen pump 4100, part of the electrolyte will be discharged from the gas-liquid separator on the anode gas outlet line 4300 of the electrochemical hydrogen pump 4100 out of the system or refluxed into the electrolyte storage device 200, and part of the electrolyte will be discharged from the gas-liquid separator on the cathode gas outlet line 4400 of the electrochemical hydrogen pump 4100 out of the system or refluxed into the electrolyte storage tank along with the water migration, which helps reduce the unnecessary loss of the electrolyte in the electrolyte storage device 200.

[0111] In some embodiments, the exhaust gas treatment system further includes a gas storage tank 910, and the gas storage tank 910 is disposed downstream of the exhaust gas pretreatment device 400. Thus, the high-pressure and high-purity hydrogen discharged from the electrochemical hydrogen pump 4100 can be stored through the gas storage tank 910 and supplied to the outside. Exemplarily, the gas storage tank 910 can be connected to the hydrogen consumption area 930 through a pipeline, and a gas release valve 920 is provided on the pipeline. For example, the hydrogen consumption area 930 can be arranged with a fuel cell to supply hydrogen to the fuel cell.

[0112] Further, the exhaust gas measuring device 500 is arranged between the electrochemical hydrogen pump 4100 and the gas storage tank 910, and the gas storage tank 910 is connected to the outlet 412 of the exhaust gas measuring device 500. Specifically, in this embodiment, the hydrogen concentration in the top gas space in the storage chamber 210 of the electrolyte storage device 200 can be detected by the first hydrogen concentration monitor 700, and the concentration of the separated and purified hydrogen can be detected by the second hydrogen concentration monitor 513. According to the concentration value obtained, the control system is used to adjust the opening of the carrier gas flow regulating valve 320 on the carrier gas pipeline (in this embodiment, the initial adjustment of the carrier gas amount is mainly based on the measured concentration of the first hydrogen concentration monitor 700, and the real-time adjustment of the carrier gas amount is based on the real-time measured concentration of the first and second hydrogen concentration monitors). Through the real-time measurement of the exhaust gas measuring device 500, the amount of hydrogen released at the reaction interface in the battery stack during the charging and discharging process of the liquid flow battery is approximately obtained, and through the calculation process described later, the additional power consumed by hydrogen release in the process is further obtained.

[0113] In some embodiments, the electrochemical hydrogen pump 4100 includes a voltage measuring device 4171 and a current measuring device 4172. The voltage measuring device 4171 is configured to measure the voltage of the current loop (the potential difference between the cathode and anode sides when the electrochemical hydrogen pump 4100 is working), and the current measuring device 4172 is configured to measure the current of the current loop. Exemplarily, the voltage measuring device 4171 can be a voltmeter, and the current measuring device 4172 can be an ammeter. The voltmeter and the ammeter are installed on the external circuit of the electrochemical hydrogen pump 4100 to detect the power consumption in the process of hydrogen separation and purification, and compare with the power consumption results obtained in the relevant calculation formulas below, so as to facilitate the necessary correction of the detection results and improve the detection accuracy.

[0114] In addition, it should be noted that Figure 3 It is only shown that the electrochemical hydrogen pump 4100 and other components are arranged downstream of the electrolyte storage device 200 on the anode side of the liquid flow battery. It should be understood that in order to meet the exhaust requirements of the liquid flow battery system, at least two electrochemical hydrogen pumps 4100 need to be arranged to separate and purify the hydrogen mixture in the top space above the electrolyte liquid level in the electrolyte storage device 200 on the cathode and anode sides of the liquid flow battery.

[0115] See also Figure 7 As shown, a flow chart of the exhaust gas treatment method of the liquid flow battery in the embodiment of the present application is shown, and the exhaust gas treatment method is implemented based on the exhaust gas treatment system 10 in the above embodiment, and the exhaust gas treatment system 10 includes an exhaust gas measurement device 500 and a control device 600. Specifically, the exhaust gas treatment method of the liquid flow battery in the embodiment of the present application includes the following steps S10 to S30:

[0116] S10. Introduce carrier gas into the top space above the electrolyte liquid level in the electrolyte storage device 200 through the carrier gas device 300 to obtain a first mixed gas.

[0117] Exemplarily, the carrier gas device 300 may include a carrier gas pipeline 310, a carrier gas flow regulating valve 320, a carrier gas filter 330, a carrier gas pressure regulator 340, and a carrier gas pressure gauge 350. The carrier gas filter 330, the carrier gas pressure regulator 340, and the carrier gas pressure gauge 350 and the carrier gas flow regulating valve 320 are sequentially arranged on the carrier gas pipeline 310. Thus, the carrier gas first passes through the carrier gas filter 330 to remove solid particulate impurities in the carrier gas, then passes through the carrier gas pressure regulator 340 to adjust the pressure of the carrier gas, then passes through the carrier gas pressure gauge 350 to detect the pressure of the carrier gas after pressure regulation to ensure that the carrier gas is reduced to a suitable pressure, and then passes through the carrier gas flow regulating valve 320 to regulate the flow rate of the carrier gas to form a carrier gas stream with the required flow rate. This carrier gas stream is finally transported to the top gas space of the storage chamber 210 of the electrolyte storage device 200 and is fully mixed with gases such as hydrogen in the top gas space of the storage chamber 210 to obtain a first mixed gas containing hydrogen.

[0118] S20. Pretreat the first mixed gas through the exhaust gas pretreatment device 400 to remove salts and moisture in the first mixed gas to obtain a second mixed gas.

[0119] Exemplarily, the exhaust gas pretreatment device 400 may be configured to remove salts and moisture in the first mixed gas. Specifically, the exhaust gas pretreatment device 400 includes a liquid storage device 410, a liquid blocking device 420, a cooling pipe 440, a bubbler 450, and a temperature measuring device 460. The liquid storage device 410 stores a cleaning liquid for removing salts in the first mixed gas. The liquid blocking device 420 is arranged in the liquid storage device 410 for filtering and removing moisture. The cooling pipe 440 extends into the cleaning liquid inside the liquid storage device 410 for cooling down the cleaning liquid. The bubbler 450 is used to evenly disperse the first mixed gas in the cleaning liquid inside the liquid storage device 410. The temperature measuring device 460 is used to measure the temperature of the cleaning liquid. When the first mixed gas passes through the bubbler 450, the cleaning liquid, and the liquid blocking device 420 in sequence, a second mixed gas with salts and moisture removed can be obtained.

[0120] S30. Measure the hydrogen concentration, pressure, volume flow rate, and temperature in the second mixed gas through the exhaust gas measuring device 500, and calculate the hydrogen discharge rate and hydrogen discharge amount.

[0121] Accordingly, the exhaust gas treatment method of the embodiment of the present application uses the carrier gas device 300 to introduce the carrier gas into the top gas space of the storage chamber 210 of the electrolyte storage device 200, so that the carrier gas is mixed with hydrogen to form a mixed gas. Thus, not only can the hydrogen concentration be regulated to maintain the hydrogen concentration within a suitable range, but also the hydrogen can be quickly discharged by regulating the carrier gas flow rate, improving the exhaust efficiency and effectively avoiding the safety risks caused by too high hydrogen concentration. Moreover, the exhaust gas pretreatment device 400 is used to remove trace salts and moisture in the mixed gas, so that not only can the influence of impurities such as salts and moisture on the measurement result of hydrogen be avoided, improving the measurement accuracy, but also the corrosion of subsequent exhaust gas measurement device 500 caused by impurities such as salts and moisture can be avoided, affecting the reliability and service life of the exhaust gas measurement device 500. Accordingly, the exhaust gas treatment method of the embodiment of the present application can measure the hydrogen concentration, pressure, volume flow rate and temperature of the gas discharged from the flow battery in real time and accurately, so as to calculate the hydrogen discharge rate and hydrogen discharge amount.

[0122] Referring to Figure 8 As shown, in some embodiments, step S10 includes:

[0123] S11. Measure the hydrogen concentration in the top gas space of the storage chamber 210 through the first hydrogen concentration monitor 700.

[0124] Exemplarily, the first hydrogen concentration monitor 700 is connected to the electrolyte storage device 200 and extends into the top gas space of the storage chamber 210. Through the first hydrogen concentration monitor 700, the hydrogen concentration in the top gas space of the storage chamber 210 of the electrolyte storage device 200 can be detected in real time, and the detected value is transmitted to the control device 600.

[0125] S12. Determine whether the hydrogen concentration in the top gas space of the storage chamber 210 exceeds the first threshold. If it exceeds the first threshold, open the carrier gas flow regulating valve 320 to introduce the carrier gas into the top gas space of the storage chamber 210 to obtain the first mixed gas; and determine whether the hydrogen concentration in the top gas space of the storage chamber 210 is lower than the second threshold. If it is lower than the second threshold, close the carrier gas flow regulating valve 320 to stop introducing the carrier gas into the top gas space of the storage chamber 210, wherein the second threshold is less than the first threshold.

[0126] Exemplarily, the first threshold may be the lower explosion concentration limit of hydrogen, that is, when the hydrogen concentration exceeds the first threshold, there may be an explosion risk. When the control device 600 obtains the real-time hydrogen concentration measured by the first hydrogen concentration monitor 700, it is necessary to determine whether the real-time hydrogen concentration exceeds the first threshold. When the real-time hydrogen concentration approaches the first threshold, the carrier gas flow regulating valve 320 can be opened to provide the carrier gas so as to reduce the hydrogen concentration in the top gas space in the storage cavity 210, avoid safety risks caused by too high hydrogen concentration, and at the same time start measuring the hydrogen discharge rate and the hydrogen discharge amount. The second threshold is less than the first threshold. When the hydrogen concentration remains lower than the second threshold for a period of time and the hydrogen discharge rate shows a downward trend, the supply of the carrier gas can be stopped at this time. And, since the measurement of the hydrogen concentration in the top gas space in the storage cavity 210 is carried out in real time, there can be a certain time interval in the measurement process, that is, the sampling period of the hydrogen concentration. Therefore, when the hydrogen concentration is lower than the second threshold, the carrier gas can be stopped, but the measurement process of the hydrogen concentration in the top gas space in the storage cavity 210 will continue.

[0127] In some embodiments, the exhaust gas measurement device 500 may include a second hydrogen concentration monitor 513, an exhaust gas pressure monitor 522, an exhaust gas flow monitor 523, and an exhaust gas temperature monitor 524. At this time, step S30 includes:

[0128] S31. Measure the hydrogen concentration in the second mixed gas through the second hydrogen concentration monitor 513. Specifically, when the gas mixer 800 mixes the second mixed gas to make the hydrogen evenly dispersed, then the hydrogen concentration in the second mixed gas is measured through the second hydrogen concentration monitor 513, making the hydrogen concentration more accurate.

[0129] S32. Measure the pressure, volume flow rate, and temperature of the second mixed gas through the exhaust gas pressure monitor 522, the exhaust gas flow monitor 523, and the exhaust gas temperature monitor 524 respectively. Specifically, the pressure, volume flow rate, and temperature of the second mixed gas are measured through the exhaust gas pressure monitor 522, the exhaust gas flow monitor 523, and the exhaust gas temperature monitor 524 respectively, and the pressure, volume flow rate, and temperature data are transmitted to the control device 600.

[0130] S33. Calculate the hydrogen discharge rate and the hydrogen discharge amount based on the hydrogen concentration in the second mixed gas and the pressure, volume flow rate, and temperature of the second mixed gas, and obtain the change of the hydrogen discharge rate and the hydrogen discharge amount over time.

[0131] Therefore, based on the measured hydrogen concentration in the second mixed gas and the pressure, volume flow rate, and temperature values of the second mixed gas, the control device 600 can accurately calculate the hydrogen concentration, pressure, volume flow rate, and temperature, and thus calculate the hydrogen discharge rate and the total amount of hydrogen discharged within a certain period of time. The following shows a specific calculation process, which is executed by the control device 600:

[0132] Under the measurement conditions of normal temperature and pressure, the mixed gas formed by hydrogen and the carrier gas is an ideal gas. From the ideal gas state equation PV = nRT, we can obtain:

[0133]

[0134] In the formula, P STP is the pressure of the ideal gas under standard conditions, V STP is the volume of the ideal gas under standard conditions, n is the amount of substance of the ideal gas, R is the ideal gas constant, and T STP is the thermodynamic temperature of the ideal gas under standard conditions; P test is the pressure of the ideal gas under the measurement conditions, V test is the volume of the ideal gas under the measurement conditions (in this embodiment, V STP and V test are the volumes of the ideal gas flowing through per unit time, that is, the flow rate), and T test is the thermodynamic temperature of the ideal gas under the measurement conditions; it should be understood that due to the difference between the actual gas and the ideal gas, under different temperature and pressure conditions, the actual gas may need to consider the gas compression factor or other correction coefficients.

[0135] Then, the instantaneous volume of the mixed gas of hydrogen and the carrier gas under standard conditions per unit time, that is, the flow rate of the mixed gas:

[0136]

[0137] In the formula, P is the pressure of the mixed gas; V is the volume of the mixed gas flowing through per unit time, that is, the flow rate; T is the temperature of the mixed gas; the subscript test is the instantaneous value under the measurement conditions, and the subscript STP is the corresponding value under standard conditions.

[0138] Furthermore, from the measured instantaneous concentration of hydrogen in the mixed gas flow, the instantaneous volume of hydrogen flowing through per unit time, that is, the flow rate of hydrogen, can be obtained:

[0139]

[0140] In the formula, is the volume of hydrogen generated per unit time under standard conditions, that is, the flow rate. For example, its unit can be sccm, slm, or Nm 3 ·h-1 etc.; is the measured concentration of hydrogen in the mixed gas stream.

[0141] Thus, the amount of substance of hydrogen generated per unit time can be obtained:

[0142]

[0143] In the formula, is the amount of substance of hydrogen generated per unit time, i.e., the hydrogen discharge rate. For example, its unit can be mol·min -1 or mol·h -1 etc.

[0144] Then, integrating the instantaneous value of the amount of substance of hydrogen obtained by calculation with respect to the time element, the total amount of substance of hydrogen discharged during the time period from the start time T1 to the end time T2 can be obtained:

[0145]

[0146] In the formula, is the total amount of substance of hydrogen generated during the set time period T1~T2, i.e., the hydrogen discharge amount. For example, its unit can be mol.

[0147] Furthermore, in some embodiments, the exhaust gas treatment method further includes: calculating the electric charge consumed by the flow battery due to hydrogen generation according to the hydrogen discharge amount. Exemplarily, since 1 mol of hydrogen is generated, 2 mol of electrons are consumed, and oxygen is generated at the same time; and from relevant calculations, the amount of substance of electrons corresponding to 1 A·h of electric charge is about 0.03731 mol. Thus, the electric charge consumed for generating 1 mol of hydrogen, i.e., hydrogen with a volume of about 22.4 L under standard conditions, is about:

[0148]

[0149] As described above, from the measurement and calculation of hydrogen, the total amount of substance of hydrogen discharged during one charge-discharge cycle can be obtained: the sum of hydrogen on the anode side and hydrogen on the cathode side. Thus, according to the total amount of substance of hydrogen, the electric charge consumed due to hydrogen generation during this charge-discharge cycle can be obtained; and the relationship between the electric charge consumed due to hydrogen generation and the reduction of battery efficiency during this charge-discharge cycle, as well as the proportion of this electric charge in the total consumed electric charge:

[0150]

[0151] In the formula, : the relationship between the electric charge consumed due to hydrogen generation and the reduction of battery efficiency during one charge-discharge cycle, as well as the proportion of this electric charge in the total consumed electric charge; : The electric quantity consumed by the generation of hydrogen on the anode side, unit: A·h; : The electric quantity consumed by the generation of hydrogen on the cathode side, unit: A·h; : The total charging quantity within the charge-discharge cycle, unit: A·h; : The total discharging quantity within the charge-discharge cycle, unit: A·h.

[0152] From the numerical value, the proportion of the influence of hydrogen generation on the battery efficiency can be known, so that effective measures can be taken to reduce hydrogen generation and improve the efficiency of the flow battery.

[0153] Furthermore, referring to Figure 8 as shown, in some embodiments, the exhaust gas treatment method further includes: Step S40, changing at least one working condition of the flow battery to obtain the hydrogen discharge rate, the hydrogen discharge amount and their changes over time, and establishing the relationship between the working condition and the hydrogen discharge rate and the hydrogen discharge amount, wherein the working condition includes the charge-discharge condition of the flow battery, the working condition of the electrolyte circulation system of the flow battery, and the working condition of the reaction interface in the flow battery stack.

[0154] Specifically, for a metal deposition type flow battery, the factors affecting hydrogen generation in the flow battery may include the electrolyte temperature, i.e., the chemical reaction temperature, the electrolyte formulation and concentration characteristics, the electrolyte flow field, the surface area of the electrodes in the battery contacting the electrolyte, the morphological characteristics of the metal deposition layer on the electrode surface, the applied potential and current, etc. List these influencing factors, and then keep other measurement conditions the same, and only keep one or more of them as variables. Under such conditions, measure and calculate the hydrogen discharge rate and the hydrogen discharge amount respectively, so as to obtain the relationship map between the dependent variable and the hydrogen discharge rate and the hydrogen discharge amount. Exemplarily, when other conditions are certain, only change the temperature of the electrolyte, and the hydrogen discharge rate at different temperatures can be measured; then from the Arrhenius equation, the trend of the hydrogen discharge rate changing with the electrolyte temperature can be obtained, or its relationship formula can be obtained. Table 1 below exemplifies the experimental design table for exploring the relationship between different working conditions of the flow battery and the hydrogen discharge rate:

[0155] Table 1 The hydrogen discharge rate of a certain metal deposition type flow battery during spontaneous reaction under different working conditions

[0156] <![CDATA[Operating condition 1, hydrogen production rate / mol·min -1 > <![CDATA[Hydrogen production rate under operating condition 2 / mol·min -1 > <![CDATA[Operating condition 3, hydrogen production rate / mol·min -1 > …… <![CDATA[Operating condition n, hydrogen production rate / mol·min -1 > The electrolyte temperature, i.e., the chemical reaction temperature Measurements 1, 2,..., n, mean, variance Measurements 1, 2,..., n, mean, variance Measurements 1, 2,..., n, mean, variance Measurements 1, 2,..., n, mean, variance Measurements 1, 2,..., n, mean, variance Electrolyte formulation and concentration characteristics Electrolyte flow field Surface area of the electrode in contact with the electrolyte Morphological characteristics of the metal deposition layer on the electrode surface

[0157] Table 2 below exemplifies the variation of the hydrogen discharge rate during the electrolysis of water for hydrogen evolution in a flow battery under different applied potentials. Specifically, the discharge rate of hydrogen generated due to the electrolysis of water for hydrogen evolution is related to factors such as the applied potential and current. Further, under the condition of keeping other influencing factors constant, the total amount of hydrogen discharged under the conditions of no applied potential (this working condition exists in the self-discharge process of the flow battery system) and different applied potentials can be measured respectively; from the measurement results, the amount of substance of hydrogen generated due to the electrolysis of water for hydrogen evolution can be obtained: the amount of substance of hydrogen generated due to the electrolysis of water for hydrogen evolution = the total amount of hydrogen generated under the applied potential working condition - the amount of hydrogen generated by the spontaneous reaction without applied potential.

[0158] Table 2 Discharge rate of hydrogen generated by the electrolysis of water for hydrogen evolution under the action of an applied potential

[0159] <![CDATA[Without an applied potential, that is, the hydrogen production rate of the spontaneous reaction / mol·min -1 > <![CDATA[Total rate of hydrogen production at an applied potential of 1 - Rate of hydrogen production in the spontaneous reaction / mol·min -1 > <![CDATA[Total hydrogen production rate at an applied potential of 2 - Spontaneous reaction hydrogen production rate / mol·min -1 > <![CDATA[Total rate of hydrogen production at an applied potential of 3 - Rate of hydrogen production in the spontaneous reaction / mol·min -1 > …… <![CDATA[Total hydrogen generation rate at an applied potential of n - Spontaneous reaction hydrogen generation rate / mol·min -1 > Measurement 1 Measurement 2 …… Measurement n Average value Variance

[0160] Alternatively, it is also possible to select the working conditions in which different thicknesses and different states of metal deposition layers are accumulated on the electrode surface of a metal deposition type flow battery during different charge-discharge cycles, measure the amount of hydrogen generated by the electrolysis of water for hydrogen evolution under different applied potentials, and directly obtain the trend of the amount of substance of hydrogen generated by the electrolysis of water for hydrogen evolution with the change of the applied potential, or obtain its relational expression.

[0161] In summary, through the above process, the hydrogen concentration, pressure, volume flow rate and temperature of the gas discharged from the flow battery can be accurately calculated, so as to calculate the hydrogen discharge rate and the hydrogen discharge amount. And based on the hydrogen discharge rate and the hydrogen discharge amount, experiments can be further designed to find out the factors affecting the hydrogen discharge rate and the hydrogen discharge amount. Thus, by analyzing the factors affecting the hydrogen discharge rate and the hydrogen discharge amount, appropriate working conditions can be selected to avoid the problems of hydrogen generation caused by these influencing factors, thereby fundamentally reducing hydrogen generation and improving battery efficiency.

[0162] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0163] The above-described embodiments only represent several implementation manners of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. An exhaust gas treatment system for a liquid flow battery, used for treating the gas discharged from the liquid flow battery, wherein: The flow battery comprises: Liquid flow battery stack; An electrolyte storage device, wherein the electrolyte storage device is provided with a liquid inlet, a liquid outlet, an air inlet and an air outlet, and the electrolyte storage device is connected with the flow battery stack through the liquid inlet and the liquid outlet to form an electrolyte circuit; Characterized in that the exhaust gas treatment system comprises: A gas carrier device, the gas carrier device comprising a gas carrier pipeline, the gas carrier pipeline being in communication with the gas inlet of the electrolyte storage device, the gas carrier device being configured to introduce a carrier gas into the electrolyte storage device; An exhaust gas pre-treatment device, wherein the inlet of the exhaust gas pre-treatment device is communicated with the air outlet, and the exhaust gas pre-treatment device is configured to pre-treat the airflow discharged from the air outlet.

2. The exhaust gas treatment system according to claim 1, characterized in that: The exhaust gas pre-treatment device comprises a liquid reservoir and a liquid blocker; The interior of the liquid reservoir is configured to store cleaning liquid, the liquid reservoir is provided with an inlet and an outlet, the inlet is connected to the gas outlet of the electrolyte storage device through a connecting pipe, and the end of the connecting pipe extends into the interior of the liquid reservoir; The liquid blocker is arranged inside the liquid reservoir and between the end of the connecting pipe and the outlet to separate the liquid level of the cleaning liquid from the outlet of the liquid reservoir, and the liquid blocker is configured to prevent liquid from passing through and allow gas to pass through; The exhaust gas pretreatment device also includes a cooling pipe, a bubbler and / or a temperature detector. The cooling pipe is passed through the outer wall of the liquid reservoir and extends into the interior of the liquid reservoir. The interior of the cooling pipe is configured to store and circulate a coolant that can cool the cleaning fluid. The bubbler is connected to the end of the connecting pipe. The bubbler is configured as a porous diffusion tube for gas diffusion. The temperature detector is connected to the liquid reservoir to monitor the temperature of the cleaning fluid.

3. The exhaust gas treatment system according to claim 1, characterized in that: The exhaust gas pretreatment device includes a gas-liquid separation device, the inlet of the gas-liquid separation device is connected to the gas outlet of the electrolyte storage device, the liquid outlet of the gas-liquid separation device is connected to the interior of the electrolyte storage device, or the liquid outlet of the gas-liquid separation device is connected to the outside.

4. The exhaust gas treatment system according to claim 1, characterized in that: The exhaust gas pretreatment device comprises an electrochemical hydrogen pump, which comprises a power source and a proton exchange membrane, a catalytic reaction layer, a gas diffusion layer, an anode bipolar plate, and a cathode bipolar plate that are bonded to each other. The proton exchange membrane is arranged between the anode bipolar plate and the cathode bipolar plate, the catalytic reaction layer is arranged between the proton exchange membrane and the anode bipolar plate and between the proton exchange membrane and the cathode bipolar plate, the gas diffusion layer is arranged between the catalytic reaction layer and the anode bipolar plate and between the catalytic reaction layer and the cathode bipolar plate, the anode bipolar plate is provided with a gas flow channel and an anode inlet and an anode outlet communicated with the gas flow channel, the cathode bipolar plate is provided with a cathode outlet, and the power source is connected to the anode bipolar plate and the cathode bipolar plate to form a current loop; The anode inlet is connected to the gas outlet of the electrolyte storage device through an anode gas inlet pipeline, the anode outlet is connected to the interior of the electrolyte storage device through an anode gas outlet pipeline, and the cathode outlet is connected to the cathode gas outlet pipeline.

5. The exhaust gas treatment system according to claim 4, characterized in that: The anode gas outlet pipeline is connected to the gas inlet of the electrolyte storage device after merging with the carrier gas pipeline; The exhaust pretreatment device also includes a three-way valve, a first shunt pipe and a second shunt pipe. One end of the first shunt pipe is connected to the carrier gas pipeline through the three-way valve, and the other end of the first shunt pipe is connected to the top space above the electrolyte level in the electrolyte storage device. One end of the second shunt pipe is connected to the carrier gas pipeline through the three-way valve, and the other end of the second shunt pipe is immersed below the electrolyte level in the electrolyte storage device.

6. The exhaust gas treatment system according to claim 4, characterized in that: The exhaust gas pretreatment device further comprises a first gas-liquid separator, a check valve, a stop valve and a first liquid return pipeline, wherein the first gas-liquid separator, the check valve and the stop valve are arranged on the anode gas outlet pipeline, and the first gas-liquid separator is connected to the interior of the electrolyte storage device via the first liquid return pipeline; and / or The exhaust gas pretreatment device further comprises a second gas-liquid separator, a flow regulator and a second liquid return pipeline, wherein the second gas-liquid separator and the flow regulator are arranged on the cathode gas outlet pipeline, and the second gas-liquid separator is connected to the interior of the electrolyte storage device through the second liquid return pipeline; and / or The exhaust gas treatment system further comprises an air storage tank, wherein the air storage tank is arranged downstream of the exhaust gas pre-treatment device; and / or The electrochemical hydrogen pump includes a voltage measurer and a current measurer. The voltage measurer is configured to measure a voltage of the current loop, and the current measurer is configured to measure a current of the current loop.

7. The exhaust gas treatment system according to claim 4, characterized in that: The proton exchange membrane, the catalytic reaction layer, the gas diffusion layer, the anode bipolar plate, and the cathode bipolar plate are all arranged in a plate-like structure, the anode bipolar plate and the cathode bipolar plate are arranged opposite to each other, and the proton exchange membrane, the catalytic reaction layer, and the gas diffusion layer are stacked between the anode bipolar plate and the cathode bipolar plate; or The proton exchange membrane, the catalytic reaction layer, the gas diffusion layer, the anode side bipolar plate, and the cathode side bipolar plate are all arranged in a tubular structure. The anode side bipolar plate is sleeved outside the cathode side bipolar plate, and the proton exchange membrane, the catalytic reaction layer and the gas diffusion layer are radially sleeved between the anode side bipolar plate and the cathode side bipolar plate.

8. The exhaust gas treatment system according to any one of claims 1 to 3, characterized in that: The exhaust gas treatment system further includes a gas mixer, which is arranged downstream of the exhaust gas pretreatment device.

9. The exhaust gas treatment system according to any one of claims 1 to 7, characterized in that: The carrier gas device comprises a carrier gas flow regulating valve, and the carrier gas flow regulating valve is arranged on the carrier gas pipeline; The carrier gas device further comprises a carrier gas filter, a carrier gas pressure regulator and / or a carrier gas pressure gauge, wherein the carrier gas filter, the carrier gas pressure regulator and / or the carrier gas pressure gauge are arranged on the carrier gas pipeline, and the carrier gas filter, the carrier gas pressure regulator and / or the carrier gas pressure gauge are located upstream of the carrier gas flow regulating valve in the carrier gas delivery direction; The exhaust treatment system further includes at least one first hydrogen concentration monitor, which is connected to the electrolyte storage device and extends into a top space above the electrolyte level in the electrolyte storage device.

10. The exhaust gas treatment system according to claim 9, characterized in that: The exhaust gas treatment system also includes an exhaust gas measuring device and a control device. The exhaust gas measuring device is connected to the outlet of the exhaust pretreatment device. The exhaust gas measuring device is configured to measure the hydrogen concentration, pressure, volume flow rate and temperature of the exhausted gas to obtain the hydrogen exhaust rate and hydrogen exhaust amount. The control device is electrically connected to the carrier gas device, the exhaust gas measuring device and the first hydrogen concentration monitor.

11. The exhaust gas treatment system according to claim 10, characterized in that: The exhaust gas measurement device includes a concentration measurement component and a flow measurement component. The concentration measurement component is connected to the outlet of the exhaust pretreatment device, and the concentration measurement component is configured to measure the hydrogen concentration in the gas discharged from the outlet of the exhaust pretreatment device. The flow measurement component is connected to the concentration measurement component, and the flow measurement component is configured to measure the pressure, volume flow and temperature of the gas discharged from the outlet of the exhaust pretreatment device.

12. The exhaust gas treatment system according to claim 11, characterized in that: The concentration measurement assembly includes a first measurement pipeline and a second hydrogen concentration monitor, wherein both ends of the first measurement pipeline are respectively connected to the outlet of the exhaust pretreatment device and the concentration measurement assembly, and the second hydrogen concentration monitor is arranged on the first measurement pipeline, and the second hydrogen concentration monitor is electrically connected to the control device; and / or The flow measurement component includes a second measuring pipeline, an exhaust pressure monitor, an exhaust flow monitor and an exhaust temperature monitor. The second measuring pipeline is connected to the concentration measurement component. The exhaust pressure monitor, the exhaust flow monitor and the exhaust temperature monitor are all arranged on the second measuring pipeline. The exhaust pressure monitor, the exhaust flow monitor and the exhaust temperature monitor are electrically connected to the control device.

13. A method for treating exhaust gas of a liquid flow battery, characterized in that: Based on the exhaust gas treatment system according to any one of claims 10 to 12, the exhaust gas treatment method comprises the following steps: Passing a carrier gas into the top space above the electrolyte level in the electrolyte storage device through the carrier gas device to obtain a first mixed gas; Pre-treating the first mixed gas by the exhaust gas pre-treatment device to obtain a second mixed gas; and The exhaust gas measuring device measures the hydrogen concentration, pressure, volume flow rate and temperature in the second mixed gas, and calculates the hydrogen exhaust rate and hydrogen exhaust amount.

14. The exhaust gas treatment method according to claim 13, characterized in that: The step of introducing a carrier gas into the head space above the electrolyte level in the electrolyte storage device through the carrier gas device comprises: measuring the hydrogen concentration in the head space above the electrolyte level in the electrolyte storage device by the first hydrogen concentration monitor; determining whether the hydrogen concentration in the head space above the electrolyte level in the electrolyte storage device exceeds a first threshold value, and if it exceeds the first threshold value, opening the carrier gas flow regulating valve to pass the carrier gas into the head space above the electrolyte level in the electrolyte storage device to obtain a first mixed gas; and Determine whether the hydrogen concentration in the top space above the electrolyte level in the electrolyte storage device is lower than a second threshold value; if so, close the carrier gas flow regulating valve to stop the introduction of carrier gas into the top space above the electrolyte level in the electrolyte storage device, wherein the second threshold value is smaller than the first threshold value.

15. The exhaust gas treatment method according to claim 13, characterized in that: The method of measuring the hydrogen concentration, pressure, volume flow rate and temperature of the second mixed gas by the exhaust gas measuring device and calculating the hydrogen exhaust rate and hydrogen exhaust amount includes: measuring the hydrogen concentration in the second mixed gas by the second hydrogen concentration monitor; respectively measuring the pressure, volume flow and temperature of the second mixed gas by the exhaust pressure monitor, the exhaust flow monitor and the exhaust temperature monitor; Calculating a hydrogen discharge rate and a hydrogen discharge amount according to the hydrogen concentration in the second mixed gas and the pressure, volume flow rate and temperature of the second mixed gas, and obtaining changes in the hydrogen discharge rate and the hydrogen discharge amount over time; Optionally, the exhaust gas treatment method further includes: Calculating the amount of electricity consumed by the flow battery to generate hydrogen based on the hydrogen discharge; and / or At least one operating condition of the liquid flow battery is changed to obtain the hydrogen emission rate and the hydrogen emission amount and their changes over time, and a relationship between the operating condition and the hydrogen emission rate and the hydrogen emission amount is established, wherein the operating condition includes the charging and discharging condition of the liquid flow battery, the operating condition of the electrolyte circulation system of the liquid flow battery, and the operating condition of the reaction interface in the liquid flow battery stack.

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