A method and system for self-oscillating regulation of a flow battery

Abstract

This invention relates to the field of flow battery technology and discloses a method and system for regulating self-excited oscillation in flow batteries. By integrating a flow oscillation generator into the electrolyte circulation loop of the flow battery, the periodic vortex ring oscillation and acoustic-fluid positive feedback phenomenon generated by the flow within the resonant cavity of this device are utilized to achieve pulsating regulation of electrolyte flow rate and pressure. This fundamentally improves the convective mass transfer efficiency at the electrode / electrolyte / diaphragm interface within the flow battery stack, thereby alleviating concentration polarization at the battery reaction interface caused by factors such as uneven flow rate, thickened diffusion boundary layer, and restricted ion migration. Furthermore, this device eliminates the need for long-term, additional electrical drive and complex control components, exhibiting a simple structure and stable operation.

Description

Technical Field

[0001] This invention relates to the field of flow battery technology, specifically to a method and system for regulating self-excited oscillation in a flow battery. Background Technology

[0002] Flow batteries store active materials involved in electrochemical reactions as electrolytes in tanks of different polarities. These electrolytes are circulated into the flow battery stack via pumps, where oxidation or reduction reactions occur at the electrode interfaces of their respective polarities, achieving the conversion and storage of electrical and chemical energy. Separating the electrodes from the electrolyte improves the cycle life of the flow battery, allowing the output power and storage capacity of the flow battery energy storage system to be independent. This enables flexible design and installation, making it suitable for the long-term energy storage needs of large-scale renewable energy sources.

[0003] Meanwhile, a flow battery system consists of multiple subsystems, including the stack, electrolyte storage tank, circulation system, and control system. A failure in any of these components can affect the overall operation. Among these, precise matching of parameters such as electrolyte concentration, temperature, and flow rate is crucial for ensuring the charge-discharge performance and lifespan of the flow battery. Deviations in electrolyte concentration or excessively low flow rates can cause concentration polarization at the reaction interface formed by the electrodes, electrolyte, and separator within the stack. This polarization occurs due to factors such as uneven flow rates, thickened diffusion boundary layers, and restricted ion migration. Consequently, it leads to impaired mass transfer at the battery's reaction interface, increased internal resistance, side reactions, and reduced charge-discharge efficiency. Therefore, complex sensing and control devices are required for real-time monitoring of the flow battery system, increasing the system's failure rate and debugging difficulty. Summary of the Invention

[0004] In view of the problems existing in the prior art, the purpose of the present invention is to provide a method and system for regulating self-excited oscillation of flow batteries, so as to alleviate the problem of mass transfer obstruction in flow batteries and improve the charging and discharging efficiency of flow batteries.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for regulating self-excited oscillation in a flow battery, characterized in that it includes:

[0006] First, a liquid flow oscillation generator is connected in series in the electrolyte circulation loop of the flow battery. The liquid flow oscillation generator includes an inlet pipe, a resonant cavity, and an outlet pipe. The outlet pipe is connected to the inlet of the flow battery stack.

[0007] Second, the electrolyte circulation loop has a stable flow rate and pressure. The liquid flows into the resonant cavity through the inlet pipe. After the flow rate and pressure are controlled by the liquid flow oscillation generator, it forms an intermittent liquid flow or an alternating strong and weak liquid flow. The liquid flows through the outlet pipe to form a jet and enters the liquid flow battery stack.

[0008] Third, due to fluid viscosity, chamber boundary effect and external disturbance, the liquid flow in the resonant cavity exchanges momentum with the surrounding fluid, generates an axisymmetric vortex ring and moves downstream.

[0009] Fourth, after the vortex ring collides with the downstream inner wall of the liquid flow oscillation generator with a resonant cavity, it generates a pressure pulse that propagates upstream. The pressure pulse propagates in the opposite direction to the liquid flow and collides with the upstream inner wall again, generating a pressure pulse that propagates downstream again. This cycle repeats, forming a pressure oscillation of the liquid flow and a closed acoustic-fluid positive feedback loop.

[0010] Fifth, when the formation frequency of the vortex ring is close to the natural frequency of the resonant cavity, the circuit selectively amplifies the vortex ring oscillation, causing large-amplitude periodic changes in the liquid pressure and velocity, thereby achieving oscillatory regulation of the electrolytic liquid pressure and flow rate; wherein, the frequency of the vortex ring is... St is the Strouhal number, v is the fluid velocity, and d is the pipe diameter; the natural frequency of the resonant cavity is related to the structural characteristics of the resonant cavity, and different fluid oscillation generating devices have different structural characteristics of the resonant cavity.

[0011] In some embodiments, the fluid oscillation generating device includes, but is not limited to, a Helmholtz resonator and a self-excited oscillating jet generating device, and it includes at least one inlet pipe and one outlet pipe, wherein:

[0012] The inlet pipe can include an upstream nozzle, and the outlet pipe can include a downstream nozzle;

[0013] The inlet and outlet pipes can be located on the same side of the resonant cavity or on different sides;

[0014] The inlet and outlet pipelines can be shared or functionally separated.

[0015] In some implementations, when the fluid oscillation generator is a Helmholtz resonator, its natural frequency is determined as follows:

[0016] Based on the principle of fluid networks, the equivalent circuit of the fluid oscillation generator is obtained, and the equations for its flow rate and pressure are as follows:

[0017]

[0018]

[0019] The total impedance of the line is:

[0020]

[0021] In the above equation, when its imaginary part is zero, series resonance occurs, that is:

[0022]

[0023] Therefore, the resonant frequency can be expressed as:

[0024]

[0025] Combining the pipeline parameters L and flow capacity C, , Substituting into the above equation, we obtain the expression for the resonant frequency as follows:

[0026]

[0027] in, Let be the gas constant, T be the temperature, m be the polytropic index, A be the neck cross-sectional area, I be the neck length, and V be the fluid chamber volume. This refers to the local speed of sound.

[0028] In some implementations, if the natural frequency of the Helmholtz resonator is not close to the formation frequency of the vortex ring, the structural characteristics related to the flow rate L and flow capacity C can be changed to make the natural frequency of the resonant cavity close to the formation frequency of the vortex ring, thereby forming an oscillating jet.

[0029] In some implementations, when the fluid oscillation generator is a self-excited oscillating jet generator, the lumped parameter equivalent circuit method in fluid network theory is used to simplify the pulsation of the resonant cavity, establish a lumped parameter fluid network model of the self-excited oscillating pulse jet, and satisfy the following second-order differential equation to describe it:

[0030]

[0031] p(t) is the instantaneous pressure. For the system damping ratio, Let k be the system's natural frequency and k be the system's amplification factor. The system's natural frequency is determined by the following formula, based on the average incoming pressure:

[0032]

[0033] The flow rate in the upstream nozzle pre-nozzle pipeline is equal to the length of the pre-nozzle pipeline divided by the pipeline area. For upstream nozzle flow resistance, For downstream nozzle flow resistance, The current capacity of the resonant cavity is equal to the cavity volume divided by the square of the fluid wave velocity within the cavity. The system damping ratio is determined by the following formula:

[0034]

[0035] The system amplification factor is determined by the following formula:

[0036]

[0037] If the initial condition is given as p(0) = 0, (0) = 0, , Then the pressure transfer function of the system is:

[0038]

[0039] Where s is a Lagrange operator;

[0040] The corresponding frequency response function, spectral characteristics, and phase frequency characteristics are as follows:

[0041]

[0042]

[0043]

[0044] The natural frequency of the self-excited oscillating jet generator is related to the flow resistance ratio of the upstream and downstream nozzles and the product of the flow rate in the pipeline and the flow volume in the chamber. It is related not only to the structural parameters of the device but also to the wave velocity of the fluid in the device.

[0045] In some embodiments, if the natural frequency of the fluid flow oscillation generator is not close to the formation frequency of the vortex ring, the structural characteristics related to the flow rate, flow capacity, and flow resistance of the fluid flow oscillation generator can be adjusted so that the natural frequency of the resonant cavity is close to the formation frequency of the vortex ring, thereby forming an oscillating fluid flow.

[0046] In some embodiments, when the liquid flow oscillation generator is a self-excited oscillation jet generator, an atomizing expansion cone can be connected to the end of the downstream nozzle before it is connected to the inlet of the flow battery stack.

[0047] In some implementations, the atomizing expansion cone adopts a stepwise expansion or conical expansion form, so that the pulsating jet forms a shear layer at the outlet and is broken up, and produces an atomization effect under the action of pressure difference, thereby obtaining atomized droplets with controllable particle size.

[0048] In some embodiments, pressure sensors and flow / velocity sensors are respectively installed upstream and downstream of the liquid flow oscillation generator or the fuel cell stack to collect the frequency and amplitude signals and their changes before and after the liquid flow self-excited oscillation in real time, and to perform closed-loop control through the following steps:

[0049] Transmit sensor signals to the flow battery management system;

[0050] Based on the state of charge of the flow battery, the power requirements of input or output, and the current self-excited oscillation parameters of the flow, the head and flow rate of the circulating pump are dynamically adjusted by comparing them with the preset target values.

[0051] By dynamically adjusting the structural features related to the flow rate, flow capacity, and flow resistance of the fluid flow oscillation generator, the frequency and amplitude of the fluid flow self-excited oscillation are kept within a range that is conducive to improving and stabilizing mass transfer efficiency.

[0052] The present invention further provides a flow battery self-excited oscillation regulation system for performing the above-described method, comprising:

[0053] Install an integrated module, which is used to connect the liquid flow oscillation generator in series in the electrolyte circulation loop of the liquid flow battery. The liquid flow oscillation generator includes an inlet pipe, a resonant cavity and an outlet pipe, and the outlet pipe is connected to the inlet of the liquid flow battery stack.

[0054] The oscillation generation module is used to introduce a stable flow rate and pressure of liquid from the electrolyte circulation loop into the resonant cavity through the inlet pipe. After the flow rate and pressure are controlled by the liquid flow oscillation generator, an intermittent or alternating strong and weak liquid flow is formed and forms a jet through the outlet pipe, which enters the fuel cell stack. In the resonant cavity, due to fluid viscosity, chamber boundary effect and external disturbance, the liquid flow exchanges momentum with the surrounding fluid, generating an axisymmetric vortex ring that moves downstream. The vortex ring collides with the downstream inner wall of the liquid flow oscillation generator with the resonant cavity, generating a pressure pulse that propagates upstream. The pressure pulse propagates in the opposite direction to the liquid flow, collides with the upstream inner wall, and generates another pressure pulse that propagates downstream. This cycle repeats, forming a pressure oscillation of the liquid flow and a closed acoustic-fluid positive feedback loop.

[0055] The oscillation matching module is used to selectively amplify the vortex ring oscillation when its formation frequency is close to the natural frequency of the resonant cavity. This causes significant periodic changes in the fluid pressure and velocity, thereby achieving oscillatory regulation of the electrolytic fluid pressure and flow rate. The frequency of the vortex ring is... St is the Strouhal number, v is the fluid velocity, and d is the pipe diameter; the natural frequency of the resonant cavity is related to the structural characteristics of the resonant cavity, and different fluid oscillation generating devices have different resonant cavity structural characteristics.

[0056] The execution adjustment module is used to install pressure sensors and flow / velocity sensors upstream and downstream of the liquid flow oscillation generator and / or the flow battery stack, respectively, to collect the frequency and amplitude signals and their changes before and after the liquid flow self-excited oscillation in real time, and to perform closed-loop control through the following steps: transmitting the sensor signals to the flow battery management system; comparing the current liquid flow self-excited oscillation parameters with preset target values ​​based on the state of charge of the flow battery, the input or output power requirements, and the current liquid flow self-excited oscillation parameters, dynamically adjusting the head and flow rate of the circulating pump, and dynamically adjusting the structural characteristics related to the flow rate, flow capacity, and flow resistance of the liquid flow oscillation generator, so that the frequency and amplitude of the liquid flow self-excited oscillation are always kept within a range that is conducive to improving and stabilizing mass transfer efficiency.

[0057] The technical solution provided by this invention has the following advantages compared with the prior art:

[0058] This invention integrates a liquid flow oscillation generator into the electrolyte circulation loop of a flow battery. Utilizing the periodic vortex ring oscillations and acoustic-fluid positive feedback generated within the resonant cavity of this device, it achieves pulsating regulation of electrolyte flow rate and pressure. This fundamentally improves the convective mass transfer efficiency at the electrode / electrolyte / diaphragm interface within the flow battery stack, thereby mitigating concentration polarization at the battery reaction interface caused by factors such as uneven flow velocity, thickened diffusion boundary layer, and restricted ion migration. Simultaneously, this device eliminates the need for long-term, additional electrical drive and complex control components, offering a simple structure and stable operation. For electrolytes with different physical properties, it maintains the self-excited oscillation frequency and amplitude within a wide range of flow and pressure conditions under certain temperature conditions, ensuring improved and stable mass transfer efficiency, demonstrating a degree of adaptability. The pulsating jet further generates controllable micron-sized atomized droplets after passing through an atomizing expansion cone, further enhancing the local turbulence intensity in the stack reaction zone and strengthening the mass transfer rate at the electrode interface. Attached Figure Description

[0059] Figure 1 This is a schematic diagram of a self-excited oscillating jet generator connected to an atomizing expansion cone according to the present invention.

[0060] Figure 2 This is a schematic diagram of a Helmholtz resonator device according to the present invention and its equivalent circuit diagram.

[0061] Figure 3 This is an equivalent circuit diagram of a self-excited oscillating jet generator according to the present invention.

[0062] Figure 4 The diagram shows two types of fluid flow oscillation generators with adjustable resonant cavity volumes according to the present invention, and their equivalent circuit diagrams.

[0063] Figure 5This is a partial schematic diagram of a flow battery system including a flow oscillation generator according to the present invention.

[0064] Figure 6 This is a block diagram of a flow battery system module / block diagram that includes a flow battery self-excited oscillation regulation system according to the present invention. Detailed Implementation

[0065] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0066] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0067] To fully understand the content of this invention, a basic understanding of fluid network principles is first required: combining fluid mechanics, electrical network theory, and transmission line theory, using flow resistance, flow capacity, and flow flux to represent corresponding electrical parameters, and the three basic parameters of resistance, capacitance, and inductance, and utilizing electrical network theory to study fluid network problems. To analyze and study a fluid pulsating system with lumped parameter characteristics, the fluid system must first be converted into an equivalent circuit represented by several lumped parameters before analysis and calculation can be performed on the established equivalent circuit. Based on the linearized fluid circuit parameter formulas, i.e., the expressions for flow resistance R, flow flux L, and flow capacity C, within a defined operating frequency range, the dominant parameter is selected as the lumped parameter of the equivalent circuit. For example, in the mass flow rate unit system, it can be calculated using the following formula:

[0068] Flow resistance (dynamic) in the linear case

[0069]

[0070] Flow resistance (dynamic) in nonlinear cases

[0071]

[0072] influenza ; flow capacity

[0073] Where p is the fluid density and A is the pipe cross-sectional area. Let be the speed of sound, I be the pipe length, K be the characteristic constant of the flow resistance, and n be the characteristic index of the flow resistance.

[0074] The flu term is usually one order lower than the flow resistance and flow capacity terms, and therefore can be ignored in many cases. Only when the system is in a resonant state or operating at high frequencies does the flu term often appear simultaneously with the flow resistance term.

[0075] To fully understand this invention, a basic understanding of the principles of fluid-induced vibration and pulsed jets is necessary: ​​During natural excitation, a resonant cavity (such as a Helmholtz resonator or a cavity structure within a living organism) has a fixed inherent resonant frequency (determined by cavity volume, opening size, fluid density / viscosity, etc.). When the frequency of an external natural disturbance (such as fluid flow, pressure fluctuations, or environmental vibrations) approaches or matches the inherent frequency of the resonant cavity, resonance occurs: the disturbance energy accumulates and amplifies continuously within the cavity, causing periodic and violent fluctuations in the pressure and velocity of the fluid (or gas) within the cavity, ultimately forming a pulsating jet through the cavity opening. This process is a passive coupling process of "natural disturbance providing initial energy → resonant cavity amplifying energy through resonance → periodic release of energy to form a pulsating jet," requiring no human intervention. Pulsed jets alter the jet's loading characteristics, applying continuous energy to the target in stages, causing intermittent impacts (essentially, pulsed jets achieve energy redistribution through pressure step transmission, a process that satisfies the law of conservation of energy). In addition, compared to external excitation methods, generating pulsating jets through natural excitation does not require additional energy input.

[0076] This invention starts from fluid network theory, introduces the concept of a liquid flow oscillation generator, and couples the resonant cavity where it is located with the flow battery stack through a fluid network cascade (series) method, thereby introducing the (low-frequency) resonance enhancement function into the flow battery system.

[0077] To achieve the above objectives, a method for regulating the self-excited oscillation of a flow battery is proposed, comprising the following steps:

[0078] Step one: Connect the liquid flow oscillation generator in series in the electrolyte circulation loop of the flow battery. The liquid flow oscillation generator includes an inlet pipe, a resonant cavity, and an outlet pipe, which is connected to the inlet of the flow battery stack. The liquid flow oscillation generator here includes, but is not limited to, a Helmholtz resonator and a self-excited oscillating jet generator; wherein, for example... Figure 1As shown, the self-excited oscillating jet generator connected to the atomizing expansion cone includes an inlet pipe containing an upstream nozzle; the device also includes at least one outlet pipe containing a downstream nozzle. The two nozzles are located on opposite sides of the resonant cavity, and the end of the downstream nozzle can be connected to the atomizing expansion cone before being connected to the inlet of the flow battery stack. The atomizing expansion cone employs a step-by-step expansion or conical expansion method, causing the pulsating jet to form a shear layer at the outlet, breaking it up and generating an atomization effect under pressure difference, thus obtaining atomized droplets with controllable particle size, such as achieving micron-level atomization. The wave velocity in the impact shear flow is related to fluid parameters such as elastic modulus, viscosity, porosity, pressure, density, and the boundary characteristics of the fluid flow within the cavity.

[0079] Step 2: The electrolyte circulation loop with stable flow rate and pressure flows into the resonant cavity through the inlet pipe. After the flow rate and pressure are controlled by the liquid flow oscillation generator, it forms an intermittent liquid flow or an alternating strong and weak liquid flow, which then forms a jet through the outlet pipe and enters the flow battery stack.

[0080] Step 3: Due to fluid viscosity, chamber boundary effects, and external disturbances, the fluid flow in the resonant cavity exchanges momentum with the surrounding fluid, generating an axisymmetric vortex ring that moves downstream.

[0081] Step four: After the vortex ring collides with the downstream inner wall of the liquid flow oscillation generator with a resonant cavity, a pressure pulse is generated that propagates upstream. The pressure pulse propagates in the opposite direction to the liquid flow and collides with the upstream inner wall again, generating a pressure pulse that propagates downstream again. This cycle repeats, forming a pressure oscillation of the liquid flow and a closed acoustic-fluid positive feedback loop.

[0082] Step 5: If the natural frequency of the liquid flow oscillation generator is not close to the formation frequency of the vortex ring, adjust the structural features related to the flow rate, and / or flow capacity, and / or flow resistance of the liquid flow oscillation generator to make the natural frequency of the resonant cavity close to the formation frequency of the vortex ring, thus forming an oscillating liquid flow; when the formation frequency of the vortex ring is close to the natural frequency of the resonant cavity, the circuit selectively amplifies the vortex ring oscillation, causing large-amplitude periodic changes in the liquid flow pressure and velocity, thereby achieving oscillatory regulation of the electrolyte flow rate and pressure; wherein:

[0083] The frequency of the vortex ring is St is the Strouhal number, v is the fluid velocity, and d is the pipe diameter. The formation frequency of the vortex ring is related to the rheological properties of the fluid, such as viscosity, elasticity, multiphase state, and compressibility, and is also related to the fluid's physical properties, such as effective density and sound velocity. The natural frequency of the resonant cavity is related to the structural characteristics of the resonant cavity; different fluid oscillation generating devices have different resonant cavity structural characteristics.

[0084] When the fluid oscillation generator is a Helmholtz resonator, its natural frequency is determined as follows:

[0085] Based on the principle of fluid networks, the equivalent circuit of the fluid oscillation generator is obtained, such as... Figure 2 As shown, the equations for obtaining its flow rate and pressure are:

[0086]

[0087]

[0088] The total impedance of the line is:

[0089]

[0090] In the above equation, when its imaginary part is zero, series resonance occurs, that is:

[0091]

[0092] Therefore, the resonant frequency can be expressed as:

[0093]

[0094] Combining the pipeline parameters L and flow capacity C, , Substituting into the above equation, we obtain the expression for the resonant frequency as follows:

[0095]

[0096] in, Let be the gas constant, T be the temperature, m be the polytropic index, A be the neck cross-sectional area, I be the neck length, and V be the fluid chamber volume. This refers to the local speed of sound.

[0097] like Figure 2 The diagram shows a schematic of a Helmholtz resonator and its equivalent circuit diagram. Based on the fluid network principle, the equivalent circuit of the fluid oscillation generator, i.e., the oscillation frequency of the RLC series resonant circuit, is entirely determined by the relevant parameters of the circuit itself. This is an inherent property of the circuit, and each RLC series resonant circuit has only one corresponding resonant frequency for resonance to occur. In practical applications, depending on the operating conditions, methods such as changing the circuit parameters L and C, or changing the frequency of the applied force, can be used to make the circuit resonate at its resonant frequency. Conversely, if resonance is undesirable in the fluid system under study, the magnitudes of parameters L and C, or the frequency ω of the applied force, are often appropriately selected to prevent the relationship between these three factors from satisfying the resonance condition, thereby eliminating resonance. From the above, the impedance is obtained... The relationship between frequency and frequency can be calculated using the following formula:

[0098]

[0099] The frequency characteristics of flow rate and pressure are further obtained and calculated using the following formulas:

[0100]

[0101]

[0102]

[0103] Replacing jw with the Lagrange operator s, we obtain the system's transfer function as:

[0104]

[0105] This is a time constant rC and The oscillating element gives the output oscillating characteristics. When the frequency of the external forced action is equal to the critical frequency of the oscillator, the oscillator resonates.

[0106] When the fluid flow oscillation generator is a self-excited oscillating jet generator, the lumped parameter equivalent circuit method in fluid network theory is used to simplify the pulsation of the resonant cavity, and an equivalent circuit diagram of a self-excited oscillating pulse jet generator is established, such as... Figure 3 As shown, the system is described by the following second-order differential equation:

[0107]

[0108] p(t) is the instantaneous pressure. For the system damping ratio, Let k be the system's natural frequency and k be the system's amplification factor. The system's natural frequency is determined by the following formula, based on the average incoming pressure:

[0109]

[0110] The flow rate in the upstream nozzle pre-nozzle pipeline is equal to the length of the pre-nozzle pipeline divided by the pipeline area. For upstream nozzle flow resistance, For downstream nozzle flow resistance, The current capacity of the resonant cavity is equal to the cavity volume divided by the square of the fluid wave velocity within the cavity. The system damping ratio is determined by the following formula:

[0111]

[0112] The system amplification factor is determined by the following formula:

[0113]

[0114] If the initial condition is given as p(0) = 0, (0) = 0, , Then the pressure transfer function of the system is:

[0115]

[0116] s is a Lagrange operator.

[0117] The corresponding frequency response function, spectral characteristics, and phase frequency characteristics are as follows:

[0118]

[0119]

[0120]

[0121] As can be seen from the above formula, the natural frequency of the self-excited oscillating jet generator is related to the flow resistance ratio of the upstream and downstream nozzles and the product of the flow rate in the pipeline and the flow capacity in the chamber. It is not only related to the structural parameters of the nozzle device, but also to the wave velocity of the fluid in the device.

[0122] Based on the above theoretical analysis, a self-excited oscillating jet generator was designed and experimentally measured (including the design of the average incoming flow pressure, upstream nozzle diameter, downstream nozzle diameter, oscillation cavity diameter, and oscillation cavity length; calculation of the device's natural frequency, damping ratio, and amplification factor; and experimental measurement of the dimensionless pressure variation with frequency). It was found that the device's frequency characteristics are nonlinear. Incoming flows of different frequencies, after entering the upstream nozzle and exiting through the downstream nozzle, produce different output pressure responses. Furthermore, the pressure response of fluid oscillation pressure signals with incoming flow pulsations below the system's natural frequency is larger, while the pressure response of pressure signals above the natural frequency is smaller. This indicates that low-frequency vibrations have a preferential characteristic through this device. Additionally, if the velocity pulsations in the incoming flow contain broadband components, when a certain frequency component matches or approaches the device's natural frequency, a resonance effect (i.e., resonance is excited through energy transfer) will occur, increasing the output pressure amplitude. After fully understanding the inherent frequency characteristics of the device and the influence of its main parameters, the structure of the self-excited oscillating jet generator can be designed based on the dominant frequency component of the incoming flow pulsation. This ensures that the low-pass frequency band of the device includes the dominant frequency band of the incoming flow, and that the device's inherent frequency is close to the dominant frequency of the incoming flow pulsation, thereby achieving a good pressure oscillation effect. This device can be used to generate pulsed jets excited by the fluid flow's own frequency. Simultaneously, the fluid loading method at the device's output end can be changed.

[0123] In some embodiments, if the natural frequency of the fluid flow oscillation generator is not close to the formation frequency of the vortex ring, structural features related to the flow rate, and / or flow capacity, and / or flow resistance of the fluid flow oscillation generator are adjusted to bring the natural frequency of the resonant cavity closer to the formation frequency of the vortex ring, thereby forming an oscillating fluid flow. In an adjustable self-excited oscillating jet generator, the flow rate in the pipeline before the upstream nozzle can be affected by adjusting the length and cross-sectional area of ​​the upstream and downstream nozzles. For example, the flow rate in this part of the pipeline can be reduced by decreasing the length L of the pipeline before the upstream nozzle or increasing the area A of this pipeline. This can ultimately increase the natural frequency of the device; the resonant cavity current capacity can be affected by adjusting the volume of the resonant cavity. For example, the current capacity of this part of the cavity can be increased by increasing the volume V of the resonator. This can ultimately reduce the natural frequency of the device. In a cascaded Helmholtz resonator, multiple resonant cavities can be connected in series or parallel to form a wideband or multi-peak resonance, thereby further extending the effective frequency range of the device from a single cavity. For example... Figure 4 The diagram shows schematics and equivalent circuit diagrams of two types of fluid flow oscillation generators with adjustable resonant cavity volumes. The fluid flow oscillation generator can be generated by adjusting the resonant cavity flow capacity (…). Or, according to the structural parameters related to (C), the natural frequency of this type of device can be controlled. For example... Figure 4 (a) shows a self-excited oscillating jet generator with adjustable resonant cavity volume; as shown in Figure 1. Figure 4 (b) shows a Helmholtz resonator with adjustable cavity volume. Part of the outer wall of the resonant cavity in the self-excited oscillating jet generator is constructed of a stretchable and contractible bellows, which can be stretched or contracted under the drive of an external mechanism, thereby adjusting the cavity volume within a certain range. A movable piston is installed on one side wall of the Helmholtz resonator's cavity, which can expand or shrink its volume under the drive of an external actuator. Both of these mechanisms can affect the resonant cavity flow capacity (…). Or C), thereby further adjusting its resonant frequency to match the resonant frequencies of each reaction chamber in the flow battery. During the operation of the flow battery, it is necessary to adapt to the system's input or output power requirements in real time according to the state of charge of the flow battery. For this purpose, it is often necessary to use motor frequency conversion technology to dynamically adjust the head and flow rate of the circulating pump by adjusting the speed of the circulating pump in real time. However, after the flow rate and pressure are controlled by the flow oscillation generator, an intermittent or alternating strong and weak flow is formed and forms a jet through the outlet pipe and enters the flow battery stack, which can often cover this part of the adjustment needs. The above adaptive adjustment process helps to simplify the functional requirements of the circulating pump in the flow battery system, saves power consumption, and keeps the self-excited oscillation frequency and amplitude of the flow at a range that is conducive to improving and stabilizing mass transfer efficiency, thereby improving the charging and discharging efficiency of the flow battery. When it is necessary to actively control the inherent frequency of such devices, the actuators of the device, such as servo motors, pistons, sliders and other mechanical devices, or other manual adjustment devices, can be controlled by the flow battery management system to actively adjust the resonant capacity of the device's resonant cavity ( By adjusting structural parameters related to (or C) the resonant cavity (such as the cavity volume V and / or neck length l), the resonant cavity frequency can be actively adjusted. This, combined with fine-tuning of the pump head and flow rate, meets the requirements for electrolyte flow rate and pressure under specific operating conditions, achieving dynamic matching. This adaptive adjustment process simplifies the functional requirements of the pump in the flow battery system, saves energy, and keeps the self-excited oscillation frequency and amplitude of the flow within a range conducive to improving and stabilizing mass transfer efficiency, thereby increasing the charge and discharge efficiency of the flow battery.

[0124] In some implementations, a fluid pressure regulator and / or flow rate meter located in the downstream pipeline of the fluid oscillation generator feeds signals back to the fluid battery management system. This system then drives the actuator to adjust the volume of the resonant cavity of the self-excited oscillating jet generator or Helmholtz resonator, thereby changing the fluid capacity and resonant frequency of the cavity. Before the resonant frequency of the cavity is fully matched with the vortex ring frequency generated by the fluid flow entering the device from upstream, the fluid pressure and flow rate measured in the downstream pipeline have not reached their maximum values ​​and exhibit fluctuations with changes in the cavity volume. The goal of active regulation technology is to find and determine the resonant cavity volume that maximizes the fluid pressure and flow rate measured in the downstream pipeline during this process.

[0125] In some implementations, such as Figure 5The diagram shows a partial schematic of a flow battery system including flow oscillation generators. Flow oscillation generators I and II are connected in series in the circulation loops of the cathode and anolyte electrolytes of the flow battery, respectively. Flow oscillation generators I and II include inlet pipes, a resonant cavity, and an outlet pipe. The outlet pipe is connected to the cathode and anolyte inlets of the flow battery stack. Fluid pressure regulators and flow meters are installed upstream and downstream of the flow oscillation generators, respectively, to collect the frequency and amplitude signals (mainly related to flow rate and pressure) and their changes before and after the self-excited oscillation of the flow in real time, and transmit this data to the flow battery management system. The flow battery system collects relevant electrical signals to determine the state of charge of the flow battery. The energy management system obtains the input or output power requirements. The fluid pressure transmitter and flow meter collect the current flow self-excited oscillation parameters and compare them with the preset target values ​​in the flow battery management system. Then, the flow battery management system dynamically adjusts the head and flow rate of the circulating pump. The flow battery management system also dynamically adjusts the structural characteristics related to the flow capacity of the flow oscillation generator to keep the flow self-excited oscillation frequency and amplitude within a range that is conducive to improving and stabilizing mass transfer efficiency.

[0126] In some implementations, as an adaptive adjustment method, multiple flow oscillation generators with resonant cavities are connected in series and / or in parallel by setting a valve upstream of the electrolyte circulation loop in the flow battery and controlling it, forming a wideband or multi-peak resonance. This extends the effective frequency range of the combined devices beyond a single resonant cavity. By designing the inherent frequency parameters of each resonant cavity, the combined devices can generate strong responses at multiple frequency points or within a continuous frequency range during the series and / or parallel connection of multiple flow oscillation generators. For a flow oscillation generator with a single resonant cavity, a strong resonance occurs when the vortex ring frequency generated by the liquid flow entering the device from upstream matches the inherent resonant frequency of the resonant cavity, resulting in the highest energy transfer efficiency and a sharp single-peak resonant response. When multiple flow oscillation generators with resonant cavities are used in combination, and the structural parameters of each resonant cavity are designed differently, their inherent resonant frequencies can be different, but a set of resonance points dispersed within a specific frequency range can be formed. When the vortex ring frequency generated by the liquid flow entering the device assembly from upstream matches the inherent resonant frequencies of multiple resonant cavities, each resonant cavity will generate a strong response (concentrated energy absorption or amplification) at its own resonant frequency, manifesting as multiple independent peaks in the response curve, i.e., multi-peak resonance. If the inherent frequencies of the multiple resonant cavities are designed to be sufficiently close (e.g., the interval between adjacent frequencies is less than the bandwidth of a single resonant peak), and the resonant peak of each resonant cavity has a certain width, then adjacent resonant peaks will overlap, forming a continuous "wideband response." Combining multiple resonant cavities with a flow battery system can provide a jet-powered stack with continuous, superimposed resonant frequencies to meet multiple complex energy storage / load requirements. Therefore, by expanding the resonant frequency coverage of the liquid flow oscillation generator, the (self-)adaptive capability of the flow battery system to multiple complex energy storage / load requirements can be improved.

[0127] Typically, a flow battery system consists of several subsystems, including the flow battery stack, the flow battery circulation system (which includes the electrolyte storage tank and circulation pump), and the flow battery management system (which includes functions such as communication, sensing, monitoring, computing, and control).

[0128] In some implementations, such as Figure 6 The diagram shows a flow battery system module / block diagram including a self-excited oscillation regulation system. It can be seen that by integrating this oscillation regulation (sub-system) with other functional subsystems of the flow battery system, the functions of self-excited oscillation and regulation of the flow are realized, thereby improving the electrochemical reaction efficiency at the electrode / electrolyte / separator interface within the battery stack. This oscillation regulation (sub-system) includes the following functional modules:

[0129] 1. Install an integrated module for connecting the liquid flow oscillation generator in series in the electrolyte circulation loop of the flow battery. The liquid flow oscillation generator includes an inlet pipe, a resonant cavity, and an outlet pipe, which is connected to the inlet of the flow battery stack.

[0130] 2. The oscillation generation module is used to introduce a stable flow rate and pressure of liquid from the electrolyte circulation loop into the resonant cavity through the inlet pipe. After the flow rate and pressure are controlled by the liquid flow oscillation generator, an intermittent or alternating strong and weak liquid flow is formed and forms a jet through the outlet pipe, which enters the fuel cell stack. In the resonant cavity, due to fluid viscosity, chamber boundary effect and external disturbance, the liquid flow exchanges momentum with the surrounding fluid, generating an axisymmetric vortex ring that moves downstream. The vortex ring collides with the downstream inner wall of the liquid flow oscillation generator with the resonant cavity, generating a pressure pulse that propagates upstream. The pressure pulse propagates in the opposite direction to the liquid flow, collides with the upstream inner wall, and generates another pressure pulse that propagates downstream. This cycle repeats, forming a pressure oscillation of the liquid flow and a closed acoustic-fluid positive feedback loop.

[0131] 3. An oscillation matching module is used to selectively amplify the vortex ring oscillation when the formation frequency of the vortex ring is close to the natural frequency of the resonant cavity, causing large-amplitude periodic changes in the liquid flow pressure and velocity, thereby achieving oscillatory regulation of the electrolyte flow rate and pressure. The formation frequency of the vortex ring is related to the rheological properties of the liquid flow, such as viscosity, elasticity, multiphase state, and compressibility, and also to the liquid flow's physical properties, such as effective density and sound velocity. The natural frequency of the resonant cavity is related to its structural characteristics; different liquid flow oscillation generators have different resonant cavity structural characteristics. If the natural frequency of the liquid flow oscillation generator is not close to the formation frequency of the vortex ring, structural features related to the flow rate, and / or flow capacity, and / or flow resistance of the liquid flow oscillation generator are adjusted. For example, the neck cross-sectional area A, and / or neck length L, and / or fluid chamber volume V of the liquid flow oscillation generator are adjusted to make the natural frequency of the resonant cavity close to the formation frequency of the vortex ring, forming an oscillating jet.

[0132] 4. Execute the adjustment module by installing pressure sensors and flow / velocity sensors upstream and downstream of the liquid flow oscillation generator and / or the flow battery stack, respectively, to collect the frequency and amplitude signals and their changes before and after the liquid flow self-excited oscillation in real time, and to perform closed-loop control through the following steps: transmit the sensor signals to the flow battery management system; compare the current liquid flow self-excited oscillation parameters with preset target values ​​based on the state of charge of the flow battery, the input or output power requirements, and the current liquid flow self-excited oscillation parameters, and dynamically adjust the head and flow rate of the circulating pump; dynamically adjust the structural features related to the flow rate, and / or flow capacity, and / or flow resistance of the liquid flow oscillation generator, such as adjusting the neck cross-sectional area A, and / or neck length L, and / or fluid chamber volume V of the liquid flow oscillation generator, so that the frequency and amplitude of the liquid flow self-excited oscillation are always kept within a range that is conducive to improving and stabilizing mass transfer efficiency.

[0133] It should be noted that the active modulation of traditional flow battery systems requires additional energy to drive changes in the flow rate and head of the circulating pump or the valve opening (e.g., using a variable frequency pump, energy consumption typically increases by 10% to 30%). In contrast, the self-excited oscillating jet generator relies entirely on the energy of the electrolyte's own flow, consuming no additional energy. Furthermore, this device has no moving parts (relying solely on the interaction between the fluid and the chamber), and by using corrosion-resistant materials (such as PTFE and titanium alloys), its overall resistance to electrolyte corrosion can be improved, thereby extending its service life. It also effectively alleviates the problems of easy valve wear and pump seal failure in traditional flow battery systems. Compared to active pressure / flow control (such as using variable frequency pumps and solenoid valves), the use of the (adjustable) self-excited oscillating jet device in flow battery systems, and its synergistic modulation effect, offers significant advantages in terms of energy consumption, cost, and reliability.

[0134] Traditional vanadium redox flow batteries (VRBs) typically employ a constant electrolyte flow mode, with the pumping system consuming approximately 10% of the discharge power, becoming a bottleneck for system efficiency improvement. In some implementations, a pulsed electrolyte strategy combining flow and stop cycles is used to test and optimize the operating state of VRBs. Experimental results show that this strategy maintains an energy efficiency of 80.5%, while reducing pumping costs by over 50%. A well-designed pulsed electrolyte can optimize the mass transfer process within the VRB, reducing energy consumption and stabilizing operation, providing crucial support for improving VRB performance. Appropriate pulsed electrolyte parameters can also help stabilize the operating temperature within the VRB stack, preventing electrolyte decomposition caused by localized processes.

[0135] Traditional flow batteries often face problems such as insufficient electrolyte mass transfer at the electrode surface and significant concentration polarization, which limits the current density and voltage efficiency. In some implementations, a sinusoidal cross-section contraction structure flow channel is used to generate a pulsating electrolyte effect. The resulting pulsating jet technology enhances the interaction between the electrolyte and electrode interface, and the pulsating electrolyte fluid regime improves the mass transfer interface of traditional flow batteries. Related experimental results show that the pulsating secondary flow generated by the sinusoidal cross-section contraction structure increases the mass transfer coefficient at the electrode surface by 2.1 times; the average ion concentration is increased by 19.1% compared to the rectangular flow channel of a traditional flow battery; and the voltage efficiency at 90% charge state reaches 82.3%, which is 7.8% higher than the parallel flow channel of a traditional flow battery. In some implementations, a flow oscillation generator is used to provide the pulsating jet. By increasing the instantaneous flow rate, the diffusion boundary layer at the electrode surface is thinned, reducing the inhibition of electrochemical reactions by concentration polarization, further stabilizing the charge-discharge curve of the flow battery, and widening the high-efficiency operating range of the flow battery.

[0136] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0137] Those skilled in the art should understand that the above description is only a specific embodiment of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application.

Claims

1. A method for regulating self-excited oscillation in a flow battery, characterized in that, include: First, a liquid flow oscillation generator is connected in series in the electrolyte circulation loop of the flow battery. The liquid flow oscillation generator includes an inlet pipe, a resonant cavity, and an outlet pipe. The outlet pipe is connected to the inlet of the flow battery stack. Second, the electrolyte circulation loop has a stable flow rate and pressure. The liquid flows into the resonant cavity through the inlet pipe. After the flow rate and pressure are controlled by the liquid flow oscillation generator, it forms an intermittent liquid flow or an alternating strong and weak liquid flow. The liquid flows through the outlet pipe to form a jet and enters the liquid flow battery stack. Third, due to fluid viscosity, chamber boundary effect and external disturbance, the liquid flow in the resonant cavity exchanges momentum with the surrounding fluid, generates an axisymmetric vortex ring and moves downstream. Fourth, after the vortex ring collides with the downstream inner wall of the liquid flow oscillation generator with a resonant cavity, it generates a pressure pulse that propagates upstream. The pressure pulse propagates in the opposite direction to the liquid flow and collides with the upstream inner wall again, generating a pressure pulse that propagates downstream again. This cycle repeats, forming a pressure oscillation of the liquid flow and a closed acoustic-fluid positive feedback loop. Fifth, when the formation frequency of the vortex ring is close to the natural frequency of the resonant cavity, the circuit selectively amplifies the vortex ring oscillation, causing large-amplitude periodic changes in the liquid pressure and velocity, thereby achieving oscillatory regulation of the electrolytic liquid pressure and flow rate; wherein, the frequency of the vortex ring is... St is the Strouhal number, v is the fluid velocity, and d is the pipe diameter; the natural frequency of the resonant cavity is related to the structural characteristics of the resonant cavity, and different fluid oscillation generating devices have different structural characteristics of the resonant cavity.

2. The self-excited oscillation regulation method for a flow battery according to claim 1, characterized in that, The fluid oscillation generator includes, but is not limited to, a Helmholtz resonator and a self-excited oscillating jet generator, and it comprises at least one inlet pipe and one outlet pipe, wherein: The inlet pipe can include an upstream nozzle, and the outlet pipe can include a downstream nozzle; The inlet and outlet pipes can be located on the same side of the resonant cavity or on different sides; The inlet and outlet pipelines can be shared or functionally separated.

3. The self-excited oscillation regulation method for a flow battery according to claim 2, characterized in that, When the fluid oscillation generator is a Helmholtz resonator, its natural frequency is determined as follows: Based on the principle of fluid networks, the equivalent circuit of the fluid oscillation generator is obtained, and the equations for its flow rate and pressure are as follows: ； ； The total impedance of the line is: ； In the above equation, when its imaginary part is zero, series resonance occurs, that is: ； Therefore, the resonant frequency can be expressed as: ； Combining the pipeline parameters L and flow capacity C, , Substituting into the above equation, we obtain the expression for the resonant frequency as follows: ； in, Let be the gas constant, T be the temperature, m be the polytropic index, A be the neck cross-sectional area, I be the neck length, and V be the fluid chamber volume. This refers to the local speed of sound.

4. The self-excited oscillation regulation method for a flow battery according to claim 3, characterized in that, If the natural frequency of the Helmholtz resonator is not close to the formation frequency of the vortex ring, the structural characteristics related to the flow rate L and flow capacity C can be changed to make the natural frequency of the resonant cavity close to the formation frequency of the vortex ring, thus forming an oscillating jet.

5. The self-excited oscillation regulation method for a flow battery according to claim 2, characterized in that, When the fluid oscillation generator is a self-excited oscillating jet generator, the lumped parameter equivalent circuit method in fluid network theory is used to simplify the pulsation of the resonant cavity, establish a lumped parameter fluid network model of the self-excited oscillating pulse jet, and satisfy the following second-order differential equation to describe it: ； p(t) is the instantaneous pressure. For the system damping ratio, Let k be the system's natural frequency and k be the system's amplification factor. The system's natural frequency is determined by the following formula, based on the average incoming pressure: ； The flow rate in the upstream nozzle pre-nozzle pipeline is equal to the length of the pre-nozzle pipeline divided by the pipeline area. For upstream nozzle flow resistance, For downstream nozzle flow resistance, The current capacity of the resonant cavity is equal to the cavity volume divided by the square of the fluid wave velocity within the cavity. The system damping ratio is determined by the following formula: ； The system amplification factor is determined by the following formula: ； If the initial condition is given as p(0) = 0, (0) = 0, , Then the pressure transfer function of the system is: ； Where s is a Lagrange operator; The corresponding frequency response function, spectral characteristics, and phase frequency characteristics are as follows: ； ； ； The natural frequency of the self-excited oscillating jet generator is related to the flow resistance ratio of the upstream and downstream nozzles and the product of the flow rate in the pipeline and the flow volume in the chamber. It is related not only to the structural parameters of the device but also to the wave velocity of the fluid in the device.

6. The method for regulating the self-excited oscillation of a flow battery according to claim 3 or 5, characterized in that, If the natural frequency of the fluid flow oscillation generator is not close to the formation frequency of the vortex ring, the structural characteristics related to the flow rate, flow capacity, and flow resistance of the fluid flow oscillation generator can be adjusted to make the natural frequency of the resonant cavity close to the formation frequency of the vortex ring, thus forming an oscillating fluid flow.

7. The self-excited oscillation regulation method for a flow battery according to claim 5, characterized in that, When the liquid flow oscillation generator is a self-excited oscillation jet generator, the end of the downstream nozzle can be connected to an atomizing expansion cone before being connected to the inlet of the liquid flow battery stack.

8. The method for regulating self-excited oscillation of a flow battery according to claim 7, characterized in that, The atomizing expansion cone adopts a step-by-step expansion or conical expansion form, which causes the pulsating jet to form a shear layer at the outlet and generate an atomization effect under the action of pressure difference, thereby obtaining atomized droplets with controllable particle size.

9. The self-excited oscillation regulation method for a flow battery according to claim 1, characterized in that, Pressure sensors and flow / velocity sensors are installed upstream and downstream of the liquid flow oscillation generator or the liquid flow battery stack, respectively, to collect the frequency and amplitude signals and their changes before and after the liquid flow self-excited oscillation in real time, and to perform closed-loop control through the following steps: Transmit sensor signals to the flow battery management system; Based on the state of charge of the flow battery, the power requirements of input or output, and the current self-excited oscillation parameters of the flow, the head and flow rate of the circulating pump are dynamically adjusted by comparing them with the preset target values. By dynamically adjusting the structural features related to the flow rate, flow capacity, and flow resistance of the fluid flow oscillation generator, the frequency and amplitude of the fluid flow self-excited oscillation are kept within a range that is conducive to improving and stabilizing mass transfer efficiency.

10. A flow battery self-excited oscillation regulation system, used to perform the method according to any one of claims 1-9, characterized in that, include: Install an integrated module, which is used to connect the liquid flow oscillation generator in series in the electrolyte circulation loop of the liquid flow battery. The liquid flow oscillation generator includes an inlet pipe, a resonant cavity and an outlet pipe, and the outlet pipe is connected to the inlet of the liquid flow battery stack. The oscillation generation module is used to introduce a stable flow rate and pressure of liquid from the electrolyte circulation loop into the resonant cavity through the inlet pipe. After the flow rate and pressure are controlled by the liquid flow oscillation generator, an intermittent or alternating strong and weak liquid flow is formed and forms a jet through the outlet pipe, which enters the fuel cell stack. In the resonant cavity, due to fluid viscosity, chamber boundary effect and external disturbance, the liquid flow exchanges momentum with the surrounding fluid, generating an axisymmetric vortex ring that moves downstream. The vortex ring collides with the downstream inner wall of the liquid flow oscillation generator with the resonant cavity, generating a pressure pulse that propagates upstream. The pressure pulse propagates in the opposite direction to the liquid flow, collides with the upstream inner wall, and generates another pressure pulse that propagates downstream. This cycle repeats, forming a pressure oscillation of the liquid flow and a closed acoustic-fluid positive feedback loop. The oscillation matching module is used to selectively amplify the vortex ring oscillation when its formation frequency is close to the natural frequency of the resonant cavity. This causes significant periodic changes in the fluid pressure and velocity, thereby achieving oscillatory regulation of the electrolytic fluid pressure and flow rate. The frequency of the vortex ring is... St is the Strouhal number, v is the fluid velocity, and d is the pipe diameter; the natural frequency of the resonant cavity is related to the structural characteristics of the resonant cavity, and different fluid oscillation generating devices have different resonant cavity structural characteristics. The execution adjustment module is used to install pressure sensors and flow / velocity sensors upstream and downstream of the liquid flow oscillation generator and / or the flow battery stack, respectively, to collect the frequency and amplitude signals and their changes before and after the liquid flow self-excited oscillation in real time, and to perform closed-loop control through the following steps: transmitting the sensor signals to the flow battery management system; comparing the current liquid flow self-excited oscillation parameters with preset target values ​​based on the state of charge of the flow battery, the input or output power requirements, and the current liquid flow self-excited oscillation parameters, dynamically adjusting the head and flow rate of the circulating pump, and dynamically adjusting the structural characteristics related to the flow rate, flow capacity, and flow resistance of the liquid flow oscillation generator, so that the frequency and amplitude of the liquid flow self-excited oscillation are always kept within a range that is conducive to improving and stabilizing mass transfer efficiency.

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