Lithium battery adaptive pulse charging and discharging dynamic regulation and control method based on ultrasonic feedback

Abstract

The invention relates to the technical field of new energy batteries, and provides a lithium battery adaptive pulse charging and discharging dynamic regulation and control method based on ultrasonic feedback, and the method comprises the steps: monitoring the state of charge of a battery in real time, and judging whether to execute a charging pulse period or not; a charging pulse period is executed, and each period sequentially comprises a front standing stage, a negative pulse stage, a rear standing stage and a positive pulse stage; detecting an ultrasonic attenuation coefficient after the positive pulse stage is ended; adjusting a positive pulse attenuation coefficient and a negative pulse time proportion; generating a charging waveform including front standing, negative pulse, rear standing and positive pulse; the lowest voltage is collected in the previous standing stage and compared with a set voltage threshold value to trigger charging termination. According to the invention, the technical problems of low efficiency, polarization accumulation and uncontrollable lithium precipitation in the final stage of traditional constant-voltage charging are solved.

Description

Technical Field

[0001] This invention belongs to the field of new energy battery technology, and in particular relates to a dynamic control method for adaptive pulse charge and discharge of lithium batteries based on ultrasonic feedback. Background Art

[0002] With the global energy structure transformation and the rapid development of renewable energy, lithium-ion batteries, as core energy storage devices, are increasingly widely used in new energy vehicles, consumer electronics, and energy storage systems. Their charging efficiency and safety directly affect the driving range of electric vehicles, user charging experience, and the total life cycle cost of batteries, making them a key technology for promoting green and low-carbon development. The current mainstream constant current-constant voltage (CC-CV) charging mode faces severe challenges at the end of the charging process (SOC≥80%): as the state of charge increases, the electrode polarization effect intensifies, and the lithium-ion diffusion rate decreases, resulting in an exponential decay of the charging current at the end of the constant voltage period. Studies have shown that the constant voltage stage accounts for 40%-60% of the total charging time during high-rate charging, becoming the core contradiction restricting the development of fast charging technology.

[0003] Driven by the "dual carbon" goals, the global new energy vehicle market has seen an average annual growth rate exceeding 30%. However, insufficient charging efficiency remains a core pain point for users, with 70% of users listing "charging time" as their primary consideration when purchasing a vehicle. Therefore, developing intelligent charging technology that integrates dynamic regulation and real-time monitoring to improve charging efficiency and enhance safety during the constant voltage phase has become a cutting-edge issue that urgently needs breakthroughs in the field of electrochemical energy storage. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, this invention proposes a dynamic control method for adaptive pulse charge and discharge of lithium batteries based on ultrasonic feedback. By deeply coupling ultrasonic non-destructive testing technology with positive and negative pulse coordinated control, the method solves the control lag problem caused by the lack of real-time sensing of the negative electrode microstate in the prior art. Furthermore, through parameter simplification and closed-loop logic design, it provides an engineering-ready solution for rapid, safe, and intelligent management of lithium-ion batteries at the end of charging. The technical solution designed in this invention includes: S10: Real-time monitoring of battery state of charge to determine whether to execute a charging pulse cycle; S20: Execute the charging pulse cycle, each cycle including the pre-rest phase, negative pulse phase, post-rest phase and positive pulse phase in sequence; S30: Detect the ultrasonic attenuation coefficient after the positive pulse phase ends; S40: Adjust the positive pulse attenuation coefficient and the negative pulse time ratio; S50: Generates a charging waveform that includes a pre-rest period, a negative pulse, a post-rest period, and a positive pulse; S60: Acquires the lowest voltage during the initial resting phase and compares it with a set voltage threshold to trigger charging termination.

[0005] Preferably, S10 further includes: Initialize the positive pulse current multiplier, negative pulse time ratio, and positive pulse attenuation coefficient.

[0006] Preferably, adjusting the positive pulse attenuation coefficient and the negative pulse time ratio includes: The ultrasonic attenuation coefficient is compared with a preset safety threshold. If the threshold is exceeded, the positive pulse attenuation coefficient is dynamically reduced and the negative pulse time ratio is increased.

[0007] Preferably, the dynamic reduction of the positive pulse attenuation coefficient includes: The adjustment range of the positive pulse attenuation coefficient is 2%-10% per cycle.

[0008] Preferably, the negative pulse phase includes: The current amplitude during the negative pulse phase is 1.5 to 3 times that during the positive pulse phase; The duration of the negative pulse phase is 5%-20% of the positive pulse duration.

[0009] Preferably, the set voltage threshold includes: The set voltage threshold is 98%-99.5% of the charging cutoff voltage.

[0010] Preferably, the ultrasonic attenuation coefficient includes: The detection result of the ultrasonic attenuation coefficient is positively correlated with the square of the lithium ion concentration gradient on the negative electrode surface and the linear combination of the interface overpotential.

[0011] Preferably, the duration of the pre-rest phase and the post-rest phase is equal to the duration of the negative pulse.

[0012] Preferably, S30 further includes: The operating frequency is 1-10MHz, and the detection sensitivity is not less than 0.1dB / cm.

[0013] Preferably, the method further includes: When the ultrasonic attenuation coefficient exceeds the safety threshold for two consecutive cycles, the charging current derating protection is triggered.

[0014] Beneficial effects: 1. This application uses ultrasonic technology to capture changes in the microscopic state inside the battery in real time, directly sensing the distribution of lithium ion concentration and the dynamics of interface reaction on the negative electrode surface. It breaks through the limitations of traditional methods that rely on macroscopic parameters such as voltage and current, providing highly sensitive and non-destructive online feedback for charging regulation, and significantly improving the timeliness and accuracy of state identification. 2. This application innovatively integrates the alternating action of positive and negative pulses with the diffusion homogenization mechanism of the resting stage. The active "backwashing" effect of the negative pulse eliminates local lithium-ion oversaturation, and the attenuation-type embedding strategy of the positive pulse simultaneously alleviates concentration polarization and charge transfer polarization, effectively reducing overpotential accumulation, improving charging efficiency and delaying battery capacity decay. 3. This application uses real-time analysis of the lithium plating tendency at the negative electrode interface based on ultrasonic signals, dynamically adjusts the positive and negative pulse parameters, and forms a closed-loop control chain of "monitoring-feedback-regulation" to achieve early warning and active suppression of lithium plating risk, thereby fundamentally improving the safety of the charging process. 4. This application simplifies the complex electrochemical model into two core control variables, which greatly reduces the algorithm complexity and ensures the efficient and real-time operation of the strategy in the vehicle battery management system; the ultrasonic detection module is highly compatible with existing battery packaging technology and can be deployed without changing the internal structure of the battery, which significantly reduces the cost of industrialization transformation. 5. This application significantly shortens the charging time at the end of the charging process while ensuring charging safety, and reduces temperature rise and side reactions during the charging process, thereby extending the battery cycle life and providing an integrated solution for fast charging and long life management of power batteries. Attached Figure Description

[0015] Figure 1 This is a flowchart illustrating a preferred embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the variation of polarization voltage with SOC in a preferred embodiment of the present invention; Figure 3 This is a schematic diagram of the dynamic change of battery voltage according to a preferred embodiment of the present invention; Figure 4 This is a schematic diagram showing the distribution of solid-phase lithium ion concentration along the normalized particle radial direction inside a single negative electrode particle according to a preferred embodiment of the present invention. Figure 5 This is a schematic diagram of the solid-phase lithium-ion distribution morphology of a preferred embodiment of the present invention; Figure 6 This is a schematic diagram showing the distribution of electrolyte salt concentration along the thickness direction of the battery in a preferred embodiment of the present invention. Detailed Implementation The embodiments of the present invention will be described in detail below. The embodiments described below are implemented based on the technical solution of the present invention, and detailed implementation methods and specific operation processes are given. However, the protection scope of the present invention is not limited to the embodiments described below.

[0016] This invention designs a dynamic control method for adaptive pulse charge and discharge of lithium batteries based on ultrasonic feedback, such as... Figure 1-6 As shown, it specifically includes: S10: Real-time monitoring of battery state of charge to determine whether to execute a charging pulse cycle; S20: Execute the charging pulse cycle, each cycle including the pre-rest phase, negative pulse phase, post-rest phase and positive pulse phase in sequence; S30: Detect the ultrasonic attenuation coefficient after the positive pulse phase ends; S40: Adjust the positive pulse attenuation coefficient and the negative pulse time ratio; S50: Generates a charging waveform that includes a pre-rest period, a negative pulse, a post-rest period, and a positive pulse; S60: Acquires the lowest voltage during the initial resting phase and compares it with a set voltage threshold to trigger charging termination.

[0017] Preferably, S10 further includes: Initialize the positive pulse current multiplier, negative pulse time ratio, and positive pulse attenuation coefficient.

[0018] Preferably, adjusting the positive pulse attenuation coefficient and the negative pulse time ratio includes: The ultrasonic attenuation coefficient is compared with a preset safety threshold. If the threshold is exceeded, the positive pulse attenuation coefficient is dynamically reduced and the negative pulse time ratio is increased.

[0019] Preferably, dynamically reducing the positive pulse attenuation coefficient includes: The positive pulse attenuation coefficient is adjusted by decreasing by 2%-10% per cycle.

[0020] Preferably, the negative pulse phase includes: The current amplitude during the negative pulse phase is 1.5 to 3 times that during the positive pulse phase; The duration of the negative pulse phase accounts for 5%-20% of the positive pulse duration.

[0021] Preferably, setting a voltage threshold includes: Set the voltage threshold to 98%-99.5% of the charging cutoff voltage.

[0022] Preferably, the ultrasonic attenuation coefficient includes: The ultrasonic attenuation coefficient is positively correlated with the square of the lithium ion concentration gradient on the negative electrode surface and the linear combination of the interface overpotential.

[0023] Preferably, the duration of the pre-rest phase and the post-rest phase are equal to the duration of the negative pulse.

[0024] Preferably, S30 further includes: The operating frequency is 1-10MHz, and the detection sensitivity is not less than 0.1dB / cm.

[0025] Specifically, this strategy is activated after the battery's state of charge (SOC) reaches 80%. The positive and negative pulses used at the end of the charging process consist of four phases within one cycle: pre-rest, negative pulse, post-rest, and positive pulse. During charging, the ultrasonic attenuation coefficient inside the battery is acquired in real time via an ultrasonic transmitter / receiver module. A quantitative relationship model is established between this coefficient and the lithium-ion concentration gradient and interface overpotential on the negative electrode surface. Two key parameters of the positive and negative pulses are dynamically adjusted based on the real-time value of the ultrasonic attenuation coefficient.

[0026] In addition, the functions of each stage of the positive and negative pulses are as follows: In the pre-resting stage, the battery is given a short period of rest time, allowing sufficient time for lithium ions and other electrolyte components inside the battery to homogenize through diffusion. This stage mainly reduces concentration polarization, also known as diffusion polarization, because during charging, local ion consumption and uneven electrolyte concentration can create concentration gradients on the electrode surface, leading to local potential fluctuations and side reactions. The resting time helps to smooth out these concentration differences, allowing the battery to enter a more stable state when entering the next stage.

[0027] Following this, in the negative pulse phase, a reverse current is applied to temporarily reverse the battery charging direction, with its amplitude typically set several times the positive pulse rate. This process acts as a "backwash," redispersing lithium ions that have accumulated at the electrode interface during forward charging, thereby reducing interfacial resistance caused by overcharging and helping to reduce charge transfer polarization. This polarization primarily reflects the problem of limited electrode reaction rates and lag in interfacial reaction kinetics. The negative pulse allows the electrode interface to regain activity, thus preparing it for the next stage of charging.

[0028] In the post-reset phase, a set resting period is established after the negative pulse ends to further stabilize the internal state of the battery. This phase not only allows the uneven ion distribution generated by the negative pulse to continue to be adjusted and diffused, but also gives the battery's open-circuit voltage a chance to recover, thereby mitigating the transient polarization caused by the negative pulse and the initial charging. The main improvement here is to address the local concentration polarization and partial interface polarization caused by the previous phase, creating a more stable starting condition for the positive pulse phase.

[0029] The positive pulse phase is the crucial part of the entire pulse charging process, aiming to steadily push the battery voltage towards the set target voltage. During this phase, when a forward charging current is applied, once the battery voltage reaches the predetermined target value, the duration of the positive pulse is recorded, and the charging rate is reduced in the next cycle. This reduction primarily helps control the overpotential of the battery as it approaches full charge, preventing uneven electrochemical reactions and overheating caused by excessive current, thereby reducing charge transfer polarization and ohmic polarization. By gradually reducing the positive pulse current, the battery can complete charging more smoothly towards the end of the charging process, reducing the risk of lithium plating and extending battery life.

[0030] Based on the above research, in-depth analysis of the mechanism of positive and negative pulses reveals that although the charging strategy involves multi-dimensional control parameters, only a few variables truly determine the charging effect and safety. Through parameter optimization and experimental verification, the control variables of the pulse charging method are finally simplified to two core parameters. This maintains the safety of the charging process while minimizing the complexity of the charging strategy, thus improving its practicality and engineering feasibility.

[0031] The first parameter is the reduction rate of the positive pulse current. This means that towards the end of the charging process, the amplitude of the positive pulse current is gradually reduced according to a certain attenuation coefficient to prevent excessive overpotential that could lead to lithium plating or enhanced side reactions near full charge. Studies have shown that as charging progresses, the lithium insertion at the negative electrode approaches saturation; continuing to apply a large current significantly increases the risk of lithium plating. Therefore, gradually reducing the positive pulse current allows the battery to complete charging more smoothly towards the end, effectively reducing charge transfer polarization and ohmic polarization, and minimizing internal heat accumulation. If this parameter is set too high, the positive pulse current decreases too quickly, potentially prolonging the charging time; conversely, if it is set too low, the decrease in positive pulse current is not significant, making it difficult to effectively suppress the risk of lithium plating. Therefore, optimizing this parameter requires striking a balance between charging time and battery safety.

[0032] The second parameter is the proportion of negative pulse duration, which is the ratio of the negative pulse duration to the positive pulse duration. The main function of the negative pulse is to redistribute lithium ions at the negative electrode interface through a "backwashing" mechanism, alleviating polarization and reducing the risk of lithium plating. However, setting the negative pulse duration requires balancing two factors: if the duration is too short, the negative pulse cannot fully exert its effect on alleviating concentration polarization, leading to a decrease in charging efficiency; if the duration is too long, it may cause additional energy loss and affect the total charging time. Therefore, the setting of this parameter needs to take into account both the polarization regulation capability of the negative pulse and the overall charging efficiency, so that the charging process is both safe and efficient.

[0033] By optimizing these two core parameters, the entire pulse charging strategy achieves the simplest control method while retaining its crucial roles in polarization regulation and lithium plating suppression. This simplified strategy not only adapts to different battery states but also facilitates practical engineering applications, enabling the charging system to achieve efficient and safe charging management in dynamic environments.

[0034] Furthermore, this application describes the electrochemical process of lithium-ion batteries at the end of charging based on a pseudo-two-dimensional (P2D) model. The model focuses on two key variables: the lithium-ion concentration in the negative electrode solid phase. Special attention should be paid to the surface concentration of particles. .

[0035] During the pre-resting phase (duration) With zero applied current, the battery primarily relies on diffusion to homogenize ions and reduce concentration polarization. To more accurately describe the diffusion process in spherical particles, the analytical solution of Fick's second law in spherical coordinates is used, and the solution is:

[0036] During the negative pulse phase, a reverse current is applied. Duration The change in surface concentration of negative electrode particles caused by a negative pulse is approximately as follows:

[0037] in The effective specific surface area of ​​the negative electrode. It is Faraday's constant. This represents the volume of the negative electrode active material. The "backwashing" effect at this stage helps reduce the local lithium-ion concentration, alleviating concentration differences and some interfacial polarization.

[0038] In the post-resting stage (duration) Similarly, without applying an external current, the concentration on the negative electrode surface continues to be homogenized through diffusion. Using the analytical solution of spherical diffusion, the concentration update in the post-resting stage can be described as:

[0039] in This represents the surface concentration at the end of the negative pulse. This stage helps to further homogenize the concentration, stabilize the interface state, and alleviate transient polarization.

[0040] During the positive pulse phase, a positive charging current is applied. (duration) This promotes lithium ion insertion into the negative electrode, increasing the concentration.

[0041] Consider a complete charging pulse cycle (cycle number) Assuming the initial concentration at the negative electrode surface is... and interface overpotential Within a complete pulse cycle, the evolution of the negative electrode surface concentration and interfacial overpotential is controlled through the combined effects of positive and negative pulses and two periods of rest. The closed-loop expression is:

[0042]

[0043]

[0044] in

[0045] This comprehensive model fully demonstrates the scientific validity of the positive and negative pulse strategy: positive pulses reduce the multiplier. It plays a decisive role in controlling the decay of the positive pulse current over the period, thereby reducing the interface overpotential. The accumulation of negative pulses helps to alleviate charge transfer and ohmic polarization; the proportion of negative pulse time This determines the effectiveness of the negative pulse's "backwashing" effect on lithium ions on the negative electrode surface, thereby reducing the risk of lithium plating caused by concentration polarization.

[0046] In lithium-ion batteries, the propagation of ultrasound in the negative electrode material is affected by local density. With elastic modulus The influence of ultrasonic waves, as well as the microstructural inhomogeneities in the material (such as lithium plating particles, interface roughness, and local defects), can also cause ultrasonic wave scattering, thereby increasing the ultrasonic attenuation coefficient. (Unit: dB / cm). In the negative electrode, the insertion or extraction of lithium ions alters the local material properties. Assuming the surface concentration of the negative electrode particles... With average particle concentration The deviation between them is

[0047] We can approximate the changes in local density and elastic modulus with lithium concentration as follows:

[0048] in and The constant describes the effect of concentration changes on physical properties, because lithium intercalation causes graphite lattice expansion, resulting in a slight decrease in local density and changes in crystal structure that alter the elastic modulus.

[0049] Local acoustic impedance Defined as:

[0050] Its change can be approximated as

[0051] Furthermore, according to Rayleigh scattering theory, when the local acoustic impedance is disturbed, the ultrasonic attenuation coefficient... The change can be approximated as being proportional to the square of the disturbance amplitude, that is:

[0052] in As the reference acoustic impedance, Let be a proportionality constant. Substitute it into... The expression, and for After normalization, we get:

[0053] Interface overpotential An increase in [a certain value] typically indicates suppressed interfacial reactions, which can easily lead to localized lithium ion accumulation and trigger lithium plating. Lithium plating forms tiny discontinuous regions or rough interfaces on the electrode surface, thereby increasing local scattering effects. To describe this phenomenon, a term related to [a certain factor] is introduced. Compensation term for linear correlation:

[0054] in This is a constant reflecting the effect of interfacial overpotential on ultrasonic attenuation. This formula indicates that when the concentration deviation at the negative electrode surface is large or the interfacial overpotential increases, the ultrasonic attenuation coefficient... It will increase significantly.

[0055] Integrating the above analysis, the closed-loop expression for a complete charging pulse cycle is:

[0056]

[0057]

[0058]

[0059] Based on this closed-loop model, when real-time ultrasound detects... Exceeding the safety threshold Adjustments are made through a feedback mechanism. and The value of , so that in the next period and This allows for improvements, enabling dynamic adaptive regulation and ensuring safe and efficient charging.

[0060] Through mathematical derivation based on the P2D model, the lithium-ion concentration on the surface of the negative electrode particles during the positive and negative pulse charging process at the end of the charging phase is described in detail. and interface overpotential The evolution of [the process]. A positive pulse attenuation coefficient was introduced. and the proportion of negative pulse time Two key parameters are described using a closed-loop expression to illustrate their influence on the internal state. To further optimize the charging process online, a method utilizing the ultrasonic attenuation coefficient is proposed. As a feedback parameter, an approximate model is given:

[0061] Among them, interface overpotential Increased elevation may lead to lithium plating or increased interface roughness, thereby enhancing the scattering effect of ultrasound waves, and consequently... Increase. Ultimately, by establishing a mapping relationship between ultrasonic attenuation and internal state and charging pulse parameters, dynamic adjustment can be achieved based on real-time ultrasonic feedback. and This enables adaptive control at the end of the charging process. This theoretical model not only mathematically describes the mechanism by which the positive and negative pulse charging strategy reduces battery polarization, controls interface overpotential, and prevents lithium plating, but also provides a scientific basis for subsequent dynamic optimization based on ultrasonic feedback, laying a solid theoretical foundation for achieving a safe and efficient charging strategy.

[0062] In addition, if Figure 2 As shown, the polarization voltage variation with SOC was revealed through constant current-constant voltage (HPPC) experiments. When SOC ≥ 80%, the polarization voltage rises sharply to above 0.11V, indicating a significant intensification of the polarization effect at the end of charging. This phenomenon verifies the fundamental reason for the decline in charging efficiency and deterioration of safety in the traditional CC-CV mode at the end of charging, providing experimental evidence for the intervention timing of the strategy in this invention (SOC ≥ 80%). Figure 3 The diagram illustrates the dynamic changes in battery voltage after employing the strategy of this invention at the end of the charging process. The charging process is divided into five stages: Pre-pulse stage: Voltage is stable, corresponding to the initial state at the end of constant current charging. Pre-resting stage: After current interruption, the voltage drops slightly, reflecting the initial relief of concentration polarization. Negative pulse stage: A reverse current is applied, causing a sharp voltage drop, forcing the lithium ions accumulated at the interface to detach through a "backwashing" effect, reducing local oversaturation. Post-resting stage: The voltage recovers, indicating that the diffusion homogenization in the resting stage effectively restores the stability of the electrode interface. Positive pulse stage: A positive decaying current is applied, and the voltage rises steadily to the target value, verifying the precise control of overpotential. Figure 4As shown, the distribution of solid-phase lithium ion concentration inside the negative electrode single particle along the normalized particle radial direction is displayed in the simulation under this charging condition, revealing the regulation path of concentration gradient evolution by the synergistic pulse mechanism of "diffusion-dominated homogenization-forced deintercalation-slow-release intercalation".

[0063] During the pre-pulse charging phase, lithium ions preferentially embed onto the particle surface (normalized position = 1.0), rapidly increasing its concentration to 9195 mol / m³. However, the concentration inside the particle (position = 0.0) is only 7250 mol / m³ due to solid-phase diffusion lag, creating a radial concentration gradient as high as 1945 mol / m³. This reflects a typical mismatch where the interfacial embedding rate is much faster than the intraparticle diffusion rate. After applying the pre-static strategy, the interruption of the charging current halts the embedding reaction. Driven by the concentration gradient, the lithium concentration inside the particle diffuses back to the surface, decreasing the surface concentration to 8927 mol / m³, while the internal concentration increases accordingly. This process conforms to the spontaneous homogenization mechanism regulated by Fickian diffusion, effectively mitigating the risk of surface oversaturation. During the negative pulse phase, the reverse current drives rapid delithiation at the interface, further reducing the surface concentration to 7690 mol / m³, forming a typical "local concentration depression" characteristic. This confirms the active "backwashing" effect of the negative pulse on interfacial lithium accumulation, thereby suppressing the limitations of electrochemical reaction kinetics. Subsequently, during the resting phase, a near-parabolic diffusion relaxation profile was observed, with the surface concentration recovering to 7831 mol / m³ and the concentration gradient further decreasing. This indicates that the lithium distribution inside and outside the particle gradually approached equilibrium, providing a safer and more uniform interface state for the subsequent application of a weak intercalation positive pulse. Finally, in the post-pulse phase, the concentration distribution was significantly smoother than before the pulse, with the surface concentration stabilizing below 8316 mol / m³ and the gradient slope also significantly decreasing. This demonstrates that the composite pulse strategy can effectively suppress the high concentration polarization phenomenon on the particle surface. To more intuitively illustrate the spatial heterogeneity of lithium distribution within the particle, such as... Figure 5 As shown, the solid-phase lithium-ion distribution morphology at different stages is further presented in the form of a three-dimensional concentration field. Compared with the radial cross-section plot, this three-dimensional graph more clearly reveals the concentration non-uniformity between the interface and the bulk phase and its dynamic evolution under the combined effects of diffusion and current. The lithium concentration at each stage in the figure ranges from early interface enrichment to a concave state after the negative pulse, and then to a more uniform distribution morphology after the pulse, fully demonstrating the active control effect of the composite pulse strategy on the location of concentration extrema and gradient distribution.

[0064] In summary, the results in the figure verify at the particle scale that the composite pulse charging strategy can synergistically regulate the lithium distribution inside the negative electrode through a "three-stage linkage mechanism" (diffusion homogenization, forced deintercalation, and decaying intercalation), thereby alleviating the imbalance between polarization and interface dynamics from the source. This provides quantitative support for further establishing a charging safety boundary based on lithium concentration gradient constraints.

[0065] In addition, if Figure 6As shown, the distribution of electrolyte salt concentration along the battery thickness direction (from negative electrode to positive electrode) under a composite pulse charging strategy simulation is illustrated. The horizontal axis represents spatial coordinates, with the left side corresponding to the negative electrode and the right side to the positive electrode. The vertical axis represents the electrolyte salt concentration, and its changes reflect the dynamic behavior of lithium ion transport and consumption in the electrolyte. In the pre-pulse stage, due to the continuous charging process, lithium ions are released from the positive electrode and migrate to the negative electrode for insertion, resulting in continuous consumption of lithium ions in the negative electrode electrolyte, forming a local concentration trough. On the positive electrode side, however, the concentration accumulates due to the lag in lithium ion migration after release, forming a clear gradient from right to left. This concentration difference not only exacerbates the polarization of the interfacial electrodes but also leads to local lithium salt dilution, affecting the interfacial reaction rate. When entering the pre-resting stage, the current is interrupted, allowing ion migration to diffuse freely, and the concentration gradient is alleviated. The concentration curve becomes significantly flatter, indicating that resting can quickly and slowly release the concentration polarization in the electrolyte phase and restore ion balance. During the negative pulse phase, an external reverse current drives lithium ions to flow back from the negative electrode to the electrolyte and migrate towards the positive electrode. During this process, the lithium salt concentration on the negative electrode side rapidly increases, while it decreases on the positive electrode side, resulting in a "reversed" concentration distribution—higher on the left and lower on the right. This artificial reverse migration process further eliminates the lithium ion scarcity problem at the negative electrode interface, while simultaneously alleviating the initial concentration buildup at the positive electrode and improving the overall electrolyte balance. In the post-resting phase, the system re-enters a free diffusion process, further leveling the concentration difference. After complete pulse strategy control, the electrolyte system has restored a good ion balance. This concentration evolution process fully demonstrates that by controlling the synergistic effect of the resting and pulse phases, the battery maintains a good ion transport environment even under high-rate charging conditions, which is beneficial for improving the battery's rate performance and lifespan stability.

[0066] Preferably, the method further includes: When the ultrasonic attenuation coefficient exceeds the safety threshold for two consecutive cycles, the charging current derating protection is triggered.

[0067] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for adaptive pulse charge / discharge dynamic control of lithium batteries based on ultrasonic feedback, characterized in that, include: S10: Real-time monitoring of battery state of charge to determine whether to execute a charging pulse cycle; S20: Execute the charging pulse cycle, each cycle including the pre-rest phase, negative pulse phase, post-rest phase and positive pulse phase in sequence; S30: Detect the ultrasonic attenuation coefficient after the positive pulse phase ends; S40: Adjust the positive pulse attenuation coefficient and the negative pulse time ratio; S50: Generates a charging waveform that includes a pre-rest period, a negative pulse, a post-rest period, and a positive pulse; S60: Acquires the lowest voltage during the initial resting phase and compares it with a set voltage threshold to trigger charging termination.

2. The adaptive pulse charge / discharge dynamic control method for lithium batteries based on ultrasonic feedback according to claim 1, characterized in that, S10 further includes: Initialize the positive pulse current multiplier, negative pulse time ratio, and positive pulse attenuation coefficient.

3. The adaptive pulse charge / discharge dynamic control method for lithium batteries based on ultrasonic feedback according to claim 1, characterized in that, The adjustment of the positive pulse attenuation coefficient and the negative pulse time ratio includes: The ultrasonic attenuation coefficient is compared with a preset safety threshold. If the threshold is exceeded, the positive pulse attenuation coefficient is dynamically reduced and the negative pulse time ratio is increased.

4. The adaptive pulse charge / discharge dynamic control method for lithium batteries based on ultrasonic feedback according to claim 3, characterized in that, The dynamic reduction of the positive pulse attenuation coefficient includes: The adjustment range of the positive pulse attenuation coefficient is 2%-10% per cycle.

5. The adaptive pulse charge / discharge dynamic control method for lithium batteries based on ultrasonic feedback according to claim 1, characterized in that, The negative pulse phase includes: The current amplitude during the negative pulse phase is 1.5 to 3 times that during the positive pulse phase; The duration of the negative pulse phase is 5%-20% of the positive pulse duration.

6. The adaptive pulse charge / discharge dynamic control method for lithium batteries based on ultrasonic feedback according to claim 1, characterized in that, The set voltage threshold includes: The set voltage threshold is 98%-99.5% of the charging cutoff voltage.

7. The adaptive pulse charge / discharge dynamic control method for lithium batteries based on ultrasonic feedback according to claim 1, characterized in that, The ultrasonic attenuation coefficient includes: The detection result of the ultrasonic attenuation coefficient is positively correlated with the square of the lithium ion concentration gradient on the negative electrode surface and the linear combination of the interface overpotential.

8. The adaptive pulse charge / discharge dynamic control method for lithium batteries based on ultrasonic feedback according to claim 1, characterized in that, The duration of the pre-rest phase and the post-rest phase are equal to the duration of the negative pulse.

9. The adaptive pulse charge / discharge dynamic control method for lithium batteries based on ultrasonic feedback according to claim 1, characterized in that, The S30 further includes: The operating frequency is 1-10MHz, and the detection sensitivity is not less than 0.1dB / cm.

10. The adaptive pulse charge / discharge dynamic control method for lithium batteries based on ultrasonic feedback according to claim 1, characterized in that, The method further includes: When the ultrasonic attenuation coefficient exceeds the safety threshold for two consecutive cycles, the charging current derating protection is triggered.

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