Lithium battery charging method, charging control device, lithium battery device, electric device and computer readable storage medium

Abstract

The application relates to the technical field of batteries, and discloses a lithium battery charging method, a charging control device, a lithium battery device, a power consumption equipment and a computer readable storage medium. The method comprises the following steps: applying a forward charging pulse to a lithium battery, so that the lithium battery is charged based on the forward charging pulse; applying a target disturbance current to the lithium battery during the forward charging pulse, the frequency of the target disturbance current being greater than the characteristic frequency of a charge transfer process in the lithium battery; and performing depolarization processing on the lithium battery after the forward charging pulse ends. The application superimposes a high-frequency target disturbance current during the forward charging pulse, continuously agitates the ion distribution at the electrode interface by rapidly changing the current direction or size at the micro level, disperses the concentration gradient before it is formed, disturbs the Nernst diffusion layer, prevents the establishment of a stable concentration gradient, reduces polarization and the formation of lithium dendrites, and improves the charging efficiency and service life of the lithium battery.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a lithium battery charging method, a charging control device, a lithium battery device, an electrical device, and a computer-readable storage medium. Background Technology

[0002] Lithium-ion batteries, with their advantages of high energy density and long cycle life, have been widely used in various fields. However, during the charging process, factors such as polarization and diffusion impedance limit the charging performance of lithium-ion batteries. Summary of the Invention

[0003] This application aims to provide a lithium battery charging method, a charging control device, a lithium battery device, an electrical device, and a computer-readable storage medium to improve the poor charging performance of lithium batteries.

[0004] In a first aspect, this application proposes a lithium battery charging method, comprising: applying a positive charging pulse to the lithium battery to charge the lithium battery based on the positive charging pulse; applying a target perturbation current to the lithium battery during the period of the positive charging pulse, wherein the frequency of the target perturbation current is greater than the characteristic frequency of the charge transfer process in the lithium battery; and performing a depolarization treatment on the lithium battery after the positive charging pulse ends.

[0005] The technical solution of this application superimposes a high-frequency target perturbation current during the forward charging pulse. By rapidly changing the direction or magnitude of the current at a microscopic level, it continuously agitates the ion distribution at the electrode interface, breaking up the concentration gradient before it forms. This perturbs the Nernst diffusion layer, preventing the establishment of a stable concentration gradient, reducing polarization and lithium dendrite formation, and improving the charging efficiency and lifespan of the lithium battery. Furthermore, the technical solution of this application performs depolarization treatment after high-frequency microscopic perturbation. The high-frequency perturbation weakens the polarization basis, while the depolarization treatment removes residual polarization through natural diffusion or passive relaxation. The synergistic effect of these two processes allows lithium ions at the negative electrode interface to migrate in a timely manner, easily keeping the negative electrode potential above the lithium plating critical potential and preventing lithium plating during fast charging.

[0006] In some embodiments, the pulse width of the forward charging pulse is greater than the characteristic time constant of the charge transfer process in the lithium battery and less than the characteristic time constant of the Weber diffusion process, wherein the characteristic time constants of the charge transfer process and the Weber diffusion process are both obtained by electrochemical impedance spectroscopy testing of the lithium battery.

[0007] This embodiment limits the pulse width of the forward charging pulse to between the characteristic time constant of the charge transfer process and the characteristic time constant of the Weber diffusion process. This ensures that the interfacial double layer is established during the pulse, the Faraday charge transfer process proceeds smoothly, and a large number of lithium ions are truly embedded in the negative electrode, thus guaranteeing fast charging efficiency. It also ensures that the forward charging pulse ends before the concentration gradient develops into steady-state Weber diffusion, avoiding the formation of a polarization layer that is difficult to eliminate. This creates conditions for subsequent depolarization treatment and is beneficial to improving the effect of depolarization treatment.

[0008] In some embodiments, the current amplitude of the forward charging pulse is ,in, ; and / or, the pulse width of the positive charging pulse is ,in, ; and / or, the current waveform of the positive charging pulse is a sine wave, a square wave, a triangular wave, or a sawtooth wave.

[0009] This embodiment selects the current amplitude of the forward charging pulse within the range of 0.2C to 20C. This ensures sufficient lithium-ion flow to migrate to the negative electrode, achieving significant charge injection and improved charging speed. Furthermore, it enables fast charging while effectively suppressing polarization and maintaining a negative electrode potential greater than 0V through high-frequency perturbation and depolarization. Selecting the pulse width of the forward charging pulse within the range of 0.001s to 100s ensures sufficient charge is injected within a single forward charging pulse for fast charging, while preventing the concentration gradient from solidifying. This allows for rapid elimination of polarization during the subsequent depolarization period, effectively avoiding lithium plating at the negative electrode and significantly improving battery cycle life.

[0010] In some embodiments, the frequency of the target disturbance current is ,in, ; and / or, the current amplitude of the target disturbance current is ,in, , , The current amplitude of the forward charging pulse; and / or, the target disturbance duration during the forward charging pulse. ,in, , , The pulse width of the positive charging pulse; and / or, the current waveform of the target disturbance current is a sine wave, square wave, triangular wave, or sawtooth wave.

[0011] This embodiment selects the target perturbation current amplitude between 5% and 30% of the forward charging pulse current amplitude. This effectively perturbs the Nernst diffusion layer while providing sufficient interfacial disruption force, without interfering with the charging process or causing additional significant temperature rise and ohmic heat loss. Select the target perturbation duration within the range to ensure that high-frequency perturbations can be performed during the charging period to hinder the establishment of the concentration gradient.

[0012] In some embodiments, applying a target perturbation current to the lithium battery during a forward charging pulse includes: controlling the transfer of the target perturbation current to the lithium battery during the forward charging pulse according to a preset first perturbation duration, wherein... , The duration of the first disturbance, The pulse width is the positive charging pulse; or, during the period of the positive charging pulse, in response to the positive charging pulse experiencing a first charging duration, the target disturbance current is controlled to be transmitted to the lithium battery according to a preset second disturbance duration, wherein, , For the second disturbance duration, The first charging duration; or, during the period of the positive charging pulse, in response to the rising edge of the positive charging pulse, the target disturbance current is controlled to be transmitted to the lithium battery according to a preset third disturbance duration. , This is the duration of the third disturbance.

[0013] The target perturbation current continues from the start of the positive charging pulse until its end, with the perturbation time completely covering the pulse width of the entire positive charging pulse. This provides uninterrupted microscopic perturbation at the interface throughout the charging process, ensuring that the establishment of the microscopic concentration gradient can be disturbed at any moment during the injection of the positive charging pulse. This perturbs the formation of the Nernst diffusion layer throughout the entire process, maximally suppressing the accumulation of concentration polarization and ensuring that the negative electrode potential remains above 0V throughout the entire positive charging phase.

[0014] In some embodiments, before applying a target perturbation current to the lithium battery during a forward charging pulse, the method further includes: determining a current state of charge (SOC) value of the lithium battery; and, in response to the current SOC value being within a preset SOC range, proceeding to the step of applying a target perturbation current to the lithium battery during a forward charging pulse.

[0015] In some embodiments, the preset state of charge range is ,in, This is the value for a fully charged state. This represents the current state of charge.

[0016] This embodiment will and Set to a preset state of charge range, when the current state of charge value is within the preset state of charge range, the target perturbation current is applied to the lithium battery during the positive charging pulse. In this way, when the negative electrode potential is about to drop below 0V, the high-frequency perturbation method can ensure that the negative electrode potential is maintained above 0V throughout the process, thus avoiding lithium plating.

[0017] In some embodiments, the depolarization process includes any one or a combination of applying a reverse discharge pulse to the lithium battery, subjecting the lithium battery to zero-current rest, and applying a target charging pulse to the lithium battery, wherein the current direction of the target charging pulse is consistent with the current direction of the forward charging pulse, and the current amplitude of the target charging pulse is less than the current amplitude of the forward charging pulse.

[0018] In some embodiments, the depolarization process includes applying a reverse discharge pulse to the lithium battery; the current amplitude of the reverse discharge pulse is... ,in, , , , The current amplitude of the forward charging pulse; and / or, the pulse width of the reverse discharging pulse. ,in, , , The pulse width of the positive charging pulse.

[0019] This embodiment is in By selecting the pulse width of the reverse discharge pulse, it is ensured that the reverse discharge pulse has a sufficient effective duration to establish a stable reverse electric field, so that lithium ions at the interface can be truly pushed back into the electrolyte, improving the depolarization effect and avoiding the power loss caused by over-discharge, thus achieving the optimal balance between depolarization effect and charging efficiency.

[0020] Optionally, the depolarization treatment includes zero-current settling of the lithium battery, the settling time being [duration to be specified]. ,in, , , The pulse width of the positive charging pulse.

[0021] This embodiment is in The range is selected for the resting time width of zero current resting. High-frequency disturbances destroy the Nernst diffusion layer during charging. Zero current resting utilizes natural diffusion and electrochemical relaxation during the gap to eliminate the concentration polarization accumulated during forward charging, so that the ion concentration at the electrode interface tends to be uniform again, avoiding lithium plating.

[0022] Optionally, the depolarization process includes applying a target charging pulse to the lithium battery, the target charging pulse having a current amplitude of ,in, , , , The current amplitude of the forward charging pulse; and / or, the pulse width of the target charging pulse. ,in, , , The pulse width of the positive charging pulse.

[0023] This embodiment is in Selecting the pulse width of the target charging pulse range not only ensures that the small current has enough time to establish a stable electrochemical relaxation process, helping lithium ions to complete meaningful diffusion and migration within the negative electrode phase, but also improves charging efficiency, achieving an optimal balance between polarization suppression and fast charging efficiency.

[0024] Optionally, applying a positive charging pulse to the lithium battery to charge the lithium battery based on the positive charging pulse includes: determining the current state of charge (SOC) value of the lithium battery; and applying a positive charging pulse to the lithium battery in response to the current SOC value being within a target SOC range to charge the lithium battery based on the positive charging pulse.

[0025] This embodiment precisely cuts in the positive charging pulse within the target state of charge range, and can intervene in time at the dangerous inflection point where polarization begins to deteriorate sharply. Through the depolarization gap of the pulse itself, it forcibly interrupts the solidification of the concentration gradient, so that the negative electrode potential is pulled back to the safe zone before sinking, avoiding the microscopic lithium deposition phenomenon that occurs in the medium and high SOC range.

[0026] Optionally, in response to the current state of charge (SOC) value of the lithium battery being within the target SOC range, a positive charging pulse is applied to the lithium battery to charge the lithium battery based on the positive charging pulse, including: in response to the current SOC value of the lithium battery being within the target SOC range, determining the current amplitude corresponding to the target SOC range as the current amplitude of the positive charging pulse; and applying the positive charging pulse to the lithium battery to charge the lithium battery based on the positive charging pulse.

[0027] Lithium-ion batteries exhibit significant differences in negative electrode lithium intercalation vacancies, solid-phase diffusion resistance, and polarization limits at different State of Charge (SOC) stages. This embodiment determines a specific current amplitude corresponding to the current SOC range. In the low / medium SOC range, where the lithium battery has strong tolerance, a large current amplitude is allocated; in the high-SOC, high-risk range, this embodiment automatically allocates a small current amplitude. This avoids the negative electrode potential dropping below 0V due to forcibly injecting a large current at the end, while ensuring that charging is carried out at the maximum permissible current at each stage under safe conditions, thereby improving charging efficiency.

[0028] Optionally, in response to the current state of charge (SBC) value of the lithium battery being within the target SBC range, determining the current amplitude corresponding to the target SBC range as the current amplitude of the forward charging pulse includes: in response to the current SBC value of the lithium battery being greater than a first SBC value and less than or equal to a second SBC value, selecting a first current amplitude as the current amplitude of the forward charging pulse; in response to the current SBC value of the lithium battery being greater than a second SBC value and less than or equal to a third SBC value, selecting a second current amplitude as the current amplitude of the forward charging pulse, wherein the second current amplitude is less than the first current amplitude; in response to the current SBC value of the lithium battery being greater than a third SBC value and less than or equal to a fourth SBC value, selecting a third current amplitude as the current amplitude of the forward charging pulse, wherein the third current amplitude is less than the second current amplitude; and in response to the current SBC value of the lithium battery being greater than a fourth SBC value and less than or equal to a fifth SBC value, selecting a fourth current amplitude as the current amplitude of the forward charging pulse, wherein the fourth current amplitude is less than the third current amplitude.

[0029] This embodiment employs a stepped current reduction strategy based on the current state of charge (SOC). In the low SOC range, a high current is maintained to seize charging time, while in the high SOC range, the current is significantly reduced to ensure charging safety. This achieves maximum charging efficiency without preventing lithium plating. As the charging process progresses, lithium intercalation saturation at the negative electrode leads to a sharp increase in solid-phase diffusion resistance. The stepped current reduction actively lowers the lithium-ion migration rate, ensuring that lithium ions always match the declining diffusion capacity. This, combined with depolarization treatment, helps reduce the risk of lithium plating.

[0030] In a second aspect, this application provides a charging control device, including a memory and a processor. The memory is connected to the processor, and the processor is used to execute one or more computer programs stored in the memory. When the processor executes one or more computer programs, it causes the charging control device to implement the lithium battery charging method described above.

[0031] In a third aspect, this application provides a lithium battery device including the aforementioned charging control device.

[0032] In a fourth aspect, this application provides an electrical device including the aforementioned lithium battery device.

[0033] In a fifth aspect, this application provides a computer-readable storage medium storing a computer program, the computer program including program instructions, which, when executed by a processor, cause the processor to perform the aforementioned lithium battery charging method.

[0034] Additional aspects and advantages of this application will be described, shown, or illustrated in part by way of implementation of the embodiments in the following description. Attached Figure Description

[0035] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, which are not intended to limit the embodiments, and elements having the same reference numerals in the drawings are designated as similar elements.

[0036] Figure 1 This is a schematic diagram of the circuit structure of a lithium battery device according to some embodiments of this application; Figure 2 This is a schematic diagram of the circuit structure of a lithium battery device according to some other embodiments of this application; Figure 3 This is a schematic diagram of the circuit structure of a lithium battery device according to some other embodiments of this application; Figure 4 A schematic flowchart illustrating a lithium battery charging method provided in some embodiments of this application; Figure 5 A schematic diagram illustrating the superposition of a target disturbance current on a positive charging pulse under a full-cycle disturbance mode, provided for some embodiments of this application; Figure 6 A first schematic diagram provided for some embodiments of this application, in which a target disturbance current is superimposed on a positive charging pulse under a hysteresis disturbance mode; Figure 7 A second schematic diagram showing, for other embodiments of this application, a target disturbance current superimposed on a positive charging pulse in a hysteresis mode; Figure 8 A schematic diagram illustrating the superposition of a target disturbance current on a positive charging pulse in a synchronous partial disturbance mode, as provided for some embodiments of this application; Figure 9 This is a schematic diagram illustrating the application of a square-waveform reverse discharge pulse to a lithium battery after the positive charging pulse ends during depolarization processing of applying a reverse discharge pulse to a lithium battery, as provided in some embodiments of this application. Figure 10 A schematic diagram illustrating the application of a sinusoidal reverse discharge pulse to a lithium battery after the positive charging pulse ends during depolarization processing of applying a reverse discharge pulse to a lithium battery, as provided in other embodiments of this application. Figure 11 This is a schematic diagram illustrating the process of zero-current resting of a lithium battery during depolarization treatment in some embodiments of this application, after the positive charging pulse ends. Figure 12 This is a schematic diagram illustrating the application of a target charging pulse to a lithium battery after the positive charging pulse ends during the depolarization process of applying a target charging pulse to the lithium battery, as provided in some embodiments of this application. Figure 13This is a schematic diagram of the structure of a charging control device provided in some embodiments of this application. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly described below with reference to the accompanying drawings of some embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this application.

[0038] In this application, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with that embodiment can be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0039] In the description of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be interpreted as an indication or implication of relative importance, nor do they imply that the specified technical features have a specific meaning in terms of quantity, specific order, or primary and secondary relationship. In the description of this application, "multiple" refers to two or more, unless otherwise clearly and specifically defined.

[0040] In the description of this application, the term "and / or" is only one way to describe the relationship between related objects, and it can represent three relationships. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document usually indicates that the related objects are in an "or" relationship; " / " can also indicate a proportional relationship; when " / " is in a table, it can also indicate that the corresponding substance and parameter do not exist. The specific meaning depends on the actual scenario.

[0041] The technical features described in the different embodiments of this application below can be combined with each other as long as they do not conflict with each other.

[0042] Lithium-ion batteries, with their significant advantages such as high energy density and long cycle life, have been widely used in various fields including electric vehicles, energy storage systems, and consumer electronics. As application scenarios continue to expand, the market is placing more stringent demands on the charging speed, cycle stability, and safety of lithium-ion batteries. During the charging process of lithium-ion batteries, polarization is a key bottleneck restricting charging performance, mainly encompassing three forms: concentration polarization, ohmic polarization, and electrochemical polarization. Among these, concentration polarization arises because the diffusion rate of lithium ions inside the electrode lags behind the electrochemical reaction rate on the electrode surface, resulting in a significant concentration gradient between the electrode surface and the interior. This is the most prevalent type of polarization under high-rate charging conditions.

[0043] Furthermore, the presence of diffusion resistance further exacerbates the polarization effect, leading to problems such as increased battery temperature rise and reduced charging efficiency. Long-term accumulation will cause irreversible capacity decay and may even induce lithium plating at the negative electrode. When the negative electrode potential drops below the lithium-ion equilibrium potential (0V) due to polarization, lithium ions cannot be smoothly inserted into the negative electrode lattice and instead deposit as metallic lithium on the particle surface. These deposited metallic lithium react with the electrolyte to form an SEI film, consuming active lithium; they also form electrochemically inert "dead lithium," increasing the battery's internal resistance. More seriously, continuously growing lithium dendrites may pierce the separator, causing an internal short circuit and ultimately leading to thermal runaway.

[0044] In related technologies, conventional constant current charging, constant voltage charging, and their combinations, as well as simple pulse charging, all have significant technical limitations in practical applications. For conventional constant current charging, a continuous high current input induces a significant concentration gradient at the interface between the negative electrode and the electrolyte, leading to the continuous accumulation of concentration polarization. Even after the charging process enters the constant voltage stage, although the charging current automatically decreases as the voltage approaches the threshold, the accumulated polarization effect is difficult to completely eliminate in a short time. Especially in low-temperature environments or high-rate fast charging conditions, this residual polarization can easily cause the negative electrode surface potential to drop below the critical value, triggering lithium dendrite growth and irreversible lithium deposition, severely damaging the battery's cycle life and safety. For conventional pulse charging, the design of the pulse parameters lacks a deep correlation with the battery's internal diffusion polarization characteristics, resulting in a charging strategy that cannot accurately match the electrode's kinetic response. This method is difficult to effectively intervene in interfacial kinetic behavior and cannot fundamentally eliminate polarization accumulation; therefore, its effect on suppressing irreversible side reactions and improving charging efficiency is very limited.

[0045] Based on this, in the charging process of lithium batteries, some embodiments of this application avoid using continuous DC charging and instead choose pulse charging to depolarize the lithium battery. At the same time, during the application of a positive charging pulse to the lithium battery, a high-frequency target perturbation current is superimposed and transmitted to the lithium battery. This can reduce the equivalent resistance of the double-layer capacitor, improve the ion migration rate, perturb the Nernst diffusion layer, and prevent the establishment of a stable concentration gradient. This can effectively buffer the diffusion impedance, reduce polarization, reduce the formation of lithium dendrites, and simultaneously take into account charging efficiency and battery safety.

[0046] This application provides a lithium battery device in some embodiments, which can be applied to electrical devices. The electrical device is not particularly limited and can be any electronic device known in the prior art. For example, the electrical device includes, but is not limited to, Bluetooth headsets, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., while spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0047] Please see Figure 1 The lithium battery device 100 includes a lithium battery 11, a charging control device 12, a charging and discharging circuit 13, a current detection circuit 14, a voltage detection circuit 15, and a power detection circuit 16.

[0048] The lithium battery 11 is used to provide energy to a load or store energy. The lithium battery 11 can be a single cell, a battery module formed by connecting multiple single cells in series, or a battery module formed by connecting multiple single cells in parallel.

[0049] The charging control device 12 serves as the control core of the lithium battery device 100, controlling the operating status of various devices and circuits. The charging control device 12 can be a dedicated chip for a microcontroller unit (MCU), digital signal processor (DSP), or battery management system (BMS).

[0050] The charge / discharge circuit 13 is electrically connected to both the lithium battery 11 and the charging control device 12. Under the control of the charging control device 12, it provides a charging circuit for the lithium battery 11 to charge it based on an external power source. Alternatively, under the control of the charging control device 12, it provides a discharging circuit for the lithium battery 11 to transfer energy from the lithium battery 11 to a load, driving the load to operate. During each charging cycle, the charge / discharge circuit 13 can provide a forward charging pulse to the lithium battery 11. After the forward charging pulse ends, it performs a depolarization process on the lithium battery 11. The depolarization process includes applying a reverse discharge pulse to the lithium battery 11, performing zero-current rest on the lithium battery 11, and applying a target charging pulse to the lithium battery 11, or any combination thereof. The charge / discharge circuit 13 can employ a bidirectional converter, for example, a Buck-Boost circuit, an H-bridge power drive circuit, or a full-bridge power drive circuit.

[0051] The technical solution of this embodiment can apply a high-frequency perturbation target current to the lithium battery 11 during the application of a positive charging pulse to the lithium battery 11. There are several ways to apply the target perturbation current during the application of the positive charging pulse to the lithium battery 11: In some embodiments, any signal can be decomposed into a superposition of two signals. At the software level, the charging control device 12 generates a reference signal, which represents the generated positive pulse signal. Then, the charging control device 12 generates a target perturbation signal corresponding to the target perturbation current, for example, a target perturbation signal with a sine wave, triangular wave, or sawtooth wave waveform generated based on a sine wave modulation algorithm, a triangular wave modulation algorithm, or a sawtooth wave modulation algorithm. The reference signal and the target perturbation signal are superimposed to obtain a final control signal. Based on the final control signal, the charging and discharging circuit 13 is controlled to apply a charging current to the lithium battery 11. This charging current is the result of the superposition of the positive charging pulse and the target perturbation current, and the characteristics of this charging current reflect the superposition effect of the positive charging pulse and the target perturbation current.

[0052] In other embodiments, please refer to Figure 2 The lithium battery device 100 also includes a current generation circuit 17, which is electrically connected to both the lithium battery 11 and the charging control device 12. Under the control of the charging control device 12, the current generation circuit 17 generates a target disturbance current and applies it to the lithium battery 11 during a positive charging pulse. The current generation circuit 17 can be a signal generator or a DC-to-AC converter circuit, etc.

[0053] The charging and discharging circuit 13 and the current generation circuit 17 operate independently in parallel and are jointly controlled by the charging control device 13. They respectively apply a positive charging pulse and a high-frequency target disturbance current to the lithium battery 11. This can reduce the equivalent resistance of the double-layer capacitance, improve the ion migration rate, disturb the Nernst diffusion layer, prevent the establishment of a stable concentration gradient, reduce polarization and reduce the formation of lithium dendrites, and improve the charging efficiency and service life of the lithium battery 11.

[0054] The current detection circuit 14 is electrically connected to both the charge / discharge circuit 13 and the charging control device 12, and is used to detect the charging current of the lithium battery 11. The circuit topology of the current detection circuit 14 can have several variations: 1) The current detection circuit 14 consists of a sampling resistor and a differential amplifier circuit. The sampling resistor is set on the charging circuit of the charging and discharging circuit 13 to sample the current flowing through the lithium battery 11 and obtain the sampling voltage. The differential amplifier circuit is electrically connected to the sampling resistor and the charging control device 12 respectively. It is used to generate a differential amplified signal based on the sampling voltage and transmit the differential amplified signal to the charging control device 12 so that the charging control device 12 can adjust the charging state of the lithium battery 11 based on the differential amplified signal and the charging algorithm.

[0055] 2) The current detection circuit 14 is a Hall current sensor. The Hall current sensor is set on the charging circuit of the charging and discharging circuit 13 to sample the current flowing through the lithium battery 11, obtain the sampling voltage, and transmit the sampling voltage to the charging control device 12 so that the charging control device 12 can adjust the charging state of the lithium battery 11 based on the sampling voltage and the charging algorithm.

[0056] The voltage detection circuit 15 is electrically connected to both the lithium battery 11 and the charging control device 12. It samples the voltage across the lithium battery 11 and transmits this voltage to the charging control device 12, enabling the charging control device 12 to perform voltage monitoring and protection operations. The voltage detection circuit 15 can be an analog front-end chip (AFE) or composed of a resistor network.

[0057] The power detection circuit 16 is electrically connected to both the lithium battery 11 and the charging control device 12, and is used to detect the state of charge (SOC) of the lithium battery 11. The SOC of the lithium battery 11 is the percentage of its remaining usable capacity to its current maximum usable capacity. The power detection circuit 16 can be a coulomb counter.

[0058] To detect the charge transfer and diffusion characteristics of lithium battery 11, please refer to... Figure 3 The lithium battery device 100 also includes an EIS (Electrochemical Impedance Spectroscopy) testing unit 18. The EIS testing unit 18 is electrically connected to the lithium battery 11 and the charging control device 12, respectively.

[0059] The charging control device 12 monitors the operating status of the lithium battery 11 in real time, selecting the stable operating conditions of the lithium battery 11 during charging intervals or DC steady state as the EIS detection window period. This avoids detection errors caused by dynamic high current conditions and ensures the accuracy of electrochemical small signal detection. After determining the EIS detection window period, the charging control device 12 activates the EIS test unit 18. The disturbance generation module built into the EIS test unit 18 generates a small-amplitude AC current excitation signal with a specific frequency band, strictly adhering to the battery electrochemical linear small signal constraint standard to avoid excessive disturbance signals causing nonlinear reactions in the lithium battery and resulting in impedance spectrum distortion.

[0060] The EIS test unit 18 superimposes the generated AC current excitation signal onto the main charging current command and outputs a control signal to the charge / discharge circuit 13. The charge / discharge circuit 13 performs signal modulation and power conversion, accurately injecting the superimposed AC excitation current signal into the lithium battery 11, thus completing the active injection of EIS AC excitation. At the moment the EIS test unit 18 synchronously injects the AC excitation current signal, the current detection circuit 14 and voltage detection circuit 15 achieve high-precision synchronous sampling at a sampling rate far exceeding the highest frequency of EIS excitation. Specifically, the current detection circuit 14 acquires the AC excitation current signal injected into the lithium battery 11 by the charge / discharge circuit 13 in real time, while the voltage detection circuit 15 synchronously acquires the AC voltage signal across the lithium battery 11. These two high-precision sampling data streams are transmitted back to the EIS test unit 18 in real time, and then uploaded by the EIS test unit 18 to the charging control device 12. Simultaneously, the power detection circuit 16 monitors the battery's SOC state and charge / discharge amount in real time, providing basic data support for EIS test condition determination and subsequent parameter compensation.

[0061] The charging control device 12, in conjunction with the EIS test unit 18, completes data processing and preprocesses the received current and voltage sampling data. It separates the independent AC components at each frequency using the Discrete Fourier Transform (DFT) or Fast Fourier Transform (FFT) algorithm, calculates the complex impedance vector corresponding to each frequency point based on the frequency domain voltage and current ratio, including the real and imaginary impedance parameters, and then fits and constructs the real-time electrochemical impedance spectrum curve of the lithium battery 11.

[0062] The charging control device 12, based on the built-in Randle equivalent circuit model, performs nonlinear fitting calculations on the collected impedance spectrum data to accurately distinguish between the electrochemical reaction at the battery interface and the lithium-ion diffusion process, and extracts the characteristic frequencies corresponding to the charge transfer process in the mid-to-high frequency range. and the characteristic frequencies of the Weber diffusion process in the low-frequency band. Among them, the characteristic frequencies corresponding to the charge transfer process. The characteristic frequencies of the Weber diffusion process corresponding to interfacial electrochemical reactions This corresponds to lithium-ion solid-phase diffusion.

[0063] The charging control device 12, by combining the conversion relationship between the electrochemical time constant and the characteristic frequency, accurately calculates the characteristic time constant of the charge transfer process of the lithium battery 11. With the characteristic time constant of the Weber diffusion process .

[0064] The charging control device 12 determines the target frequency range of the high-frequency disturbance current (i.e., the target disturbance current) based on the characteristic time constant of the charge transfer process, ensuring that the frequency of the target disturbance current is greater than the characteristic frequency of charge transfer, thereby reducing the equivalent impedance of the double layer. Simultaneously, it sets the upper limit of the width of the forward charging pulse based on the characteristic time constant of the Weber diffusion process, ensuring that the pulse duration is less than the diffusion steady-state establishment time, thus utilizing the high mass transfer efficiency of unsteady-state diffusion to suppress concentration polarization. Therefore, the charging control device 12 uses the characteristic time constants of the charge transfer process and the Weber diffusion process as core quantitative bases, dynamically and adaptively adjusting the operating parameters of the charging and discharging circuit 13, such as the charging pulse width and charging current amplitude, to achieve refined and dynamic optimization of the battery charging strategy while ensuring lithium battery charging safety and suppressing lithium plating aging.

[0065] The following embodiments of this application provide a lithium battery charging method. Please refer to... Figure 4 In some embodiments of this application, the lithium battery is charged through steps S41 to S43, as detailed below: Step S41: Apply a positive charging pulse to the lithium battery so that the lithium battery is charged based on the positive charging pulse.

[0066] A forward charging pulse is a current signal that flows forward into a lithium battery to charge it, with a certain time width and current amplitude. The waveform of the forward charging pulse can be a square wave, etc. The technical solution of this embodiment outputs a forward charging pulse according to a preset current amplitude and pulse width, applying the forward charging pulse to the lithium battery to provide charging energy to the lithium battery at a higher rate. This causes lithium ions to be extracted from the positive electrode and migrate through the electrolyte to the negative electrode, thereby improving the battery's state of charge (SOC). Furthermore, this embodiment uses a pulsed forward charging pulse instead of a continuous large DC current, thus creating conditions for subsequent depolarization processing and preventing the polarization establishment process caused by a continuous large DC current.

[0067] In some embodiments, the current amplitude of the forward charging pulse is ,in, For example, the current amplitude of the forward charging pulse can be selected from any value between 0.2C and 20C, or a range between any two values, such as any value of 0.2C, 5C, 10C, 15C, 20C, or any range between 5C and 10C, 10C and 15C.

[0068] If the current amplitude of the forward charging pulse is less than 0.2C, the charging current of the lithium battery is too small, resulting in very little charge injected into the lithium battery per unit time. In this case, in order to achieve the target SOC of the lithium battery, the charging time needs to be extended, negating the purpose of fast charging. If the current amplitude of the forward charging pulse exceeds 20C, the instantaneous charging rate is high, and the influx rate of lithium ions at the negative electrode or electrolyte interface will exceed the physical limit that the target disturbance current can intervene in, thus negating the effect of the target disturbance current. Furthermore, a high charging current can easily cause the temperature of the lithium battery to rise, leading to thermal runaway safety hazards; at the same time, the negative electrode potential drops below 0V, directly causing irreversible and severe lithium plating and lithium dendrite growth.

[0069] The technical solution of this embodiment selects the current amplitude of the positive charging pulse in the range of 0.2C to 20C, which can ensure that there is enough lithium ion flow to migrate to the negative electrode, achieve significant power injection and charging speed improvement, and achieve fast charging while ensuring that polarization is effectively suppressed and the negative electrode potential is maintained above 0V through high-frequency perturbation and depolarization.

[0070] In some embodiments, the pulse width of the forward charging pulse is ,in, For example, the pulse width of the positive charging pulse can be selected from any value between 0.001s (i.e. 1ms) and 100s, or a range between any two values, such as any value of 0.001s, 0.01s, 0.1s, 1s, 10s, 100s, or any range between 1s and 10s, or between 10s and 100s.

[0071] If the pulse width of the forward charging pulse is less than 1 ms, the amount of electricity injected into the lithium battery is small within a short duration, resulting in low charging efficiency. Furthermore, timescales of 1 ms and below are close to or lower than the characteristic time constant of the charge transfer process. In this case, the applied forward pulse current primarily charges and discharges the double-layer capacitor, without actually triggering lithium-ion insertion into the bulk phase of the negative electrode particles, thus failing to achieve a charging effect. If the pulse width of the forward charging pulse exceeds 100 seconds, the lithium battery remains in a high-current injection state for too long. After a duration of tens of seconds, the microscopic agitation effect of the target perturbation current will be unable to counteract the huge ion concentration difference caused by the long-term continuous high current. Lithium ions on the negative electrode surface easily form a concentration polarization layer with extremely thick thickness, and the negative electrode potential easily drops below 0V, leading to lithium plating.

[0072] The technical solution of this embodiment selects the pulse width of the positive charging pulse within the range of 0.001s to 100s. This ensures that sufficient charge is injected within a single positive charging pulse to achieve fast charging, while also ensuring that the concentration gradient does not solidify. This allows for rapid elimination of polarization during the subsequent depolarization period, effectively preventing lithium plating on the negative electrode and significantly improving the cycle life of the battery.

[0073] The pulse width of the forward charging pulse is greater than the characteristic time constant of the charge transfer process in the lithium battery and less than the characteristic time constant of the Weber diffusion process. The characteristic time constants of the charge transfer process and the Weber diffusion process are both obtained by electrochemical impedance spectroscopy of the lithium battery.

[0074] The characteristic time constant of the charge transfer process describes the rate at which lithium ions complete the Faraday reaction at the electrode or electrolyte interface. This characteristic time constant reflects the threshold time at which a positive pulse charge can truly drive lithium ions to embed into the negative electrode lattice. The technical solution of this embodiment extracts the charge transfer resistance by fitting the semi-circular arc at the boundary between the high-frequency and mid-frequency regions of the Nyquist plot. and double-layer capacitor Based on charge transfer resistance and double-layer capacitor The characteristic time constant of the charge transfer process is obtained.

[0075] If the pulse width of the forward charging pulse is less than the characteristic time constant of the charge transfer process, the charging process merely charges and discharges the double-layer capacitor without triggering an actual lithium-ion insertion reaction, which is considered invalid charging. The pulse width of the forward charging pulse is greater than the characteristic time constant of the charge transfer process, thus ensuring that substantial lithium-ion insertion into the negative electrode phase occurs during the pulse.

[0076] The characteristic time constant of the Weber diffusion process describes the time required for lithium ions to establish a steady state within the electrode material and at the electrode or electrolyte interface due to concentration gradients. This embodiment's technical solution obtains the characteristic time constant of the Weber diffusion process from the characteristic cutoff frequency in the low-frequency region of the Nyquist plot. If the pulse width of the forward charging pulse is greater than the characteristic time constant of the Weber diffusion process, it means that under continuous injection of a large current, the lithium ion accumulation on the negative electrode surface has formed a steady-state concentration gradient, and concentration polarization has solidified and accumulated. By limiting the pulse width of the forward charging pulse to less than the characteristic time constant of the Weber diffusion process, it ensures that the forward current is forcibly cut off and depolarization is initiated before the concentration gradient is fully established.

[0077] The technical solution of this embodiment limits the pulse width of the forward charging pulse to between the characteristic time constant of the charge transfer process and the characteristic time constant of the Weber diffusion process. This ensures that the interface double layer is established during the pulse, the Faraday charge transfer process proceeds smoothly, and a large number of lithium ions are truly embedded in the negative electrode, thus guaranteeing fast charging efficiency. It also ensures that the forward charging pulse ends before the concentration gradient develops into steady-state Weber diffusion, avoiding the formation of a polarization layer that is difficult to eliminate. This creates conditions for subsequent depolarization treatment and is beneficial to improving the effect of depolarization treatment.

[0078] Step S42: During the positive charging pulse, a target perturbation current is applied to the lithium battery. The frequency of the target perturbation current is greater than the characteristic frequency of the charge transfer process in the lithium battery.

[0079] The target perturbation current is a high-frequency, low-amplitude alternating current signal superimposed on the forward charging pulse during its duration. The waveform of the target perturbation current can be a sine wave, square wave, triangular wave, or sawtooth wave. This embodiment applies a target perturbation current to the lithium battery during the forward charging pulse. The high-frequency alternating target perturbation current can accelerate the charge transfer rate at the electrode or electrolyte interface, improve the migration of lithium ions in the double layer, and thus reduce the equivalent resistance of the double-layer capacitance. Simultaneously, the target perturbation current can disrupt the concentration gradient of lithium ions that is steadily forming on the negative electrode surface, preventing the accumulation of concentration polarization and thus preventing the negative electrode potential from dropping below the lithium plating potential (e.g., 0V).

[0080] In some embodiments, the frequency of the target disturbance current is ,in, For example, the frequency of the target disturbance current can be selected from any value between 500Hz and 20kHz, or a range between any two values, such as any value of 500Hz, 1000Hz, 1500Hz, 2000Hz, 10kHz, 20kHz, etc., or any range between 2000Hz and 10kHz, 10kHz and 20kHz, etc.

[0081] If the frequency of the target perturbation current is below 500Hz, it exhibits slow, low-frequency fluctuations rather than high-frequency micro-perturbations. Such low-frequency fluctuations not only fail to effectively excite the low-resistance channels of the double-layer capacitor, but also, due to their excessively long cycle, cause lithium-ion directional accumulation to resume within half a cycle, failing to disrupt the establishment of the Nernst diffusion layer and easily affecting the depolarization effect. If the frequency of the target perturbation current exceeds 20kHz, the excessively high frequency leads to a sharp increase in the impedance of parasitic inductance and capacitance in the charging circuit. The technical solution of this embodiment selects the frequency of the target perturbation current between 500Hz and 20kHz, which ensures both the establishment of the Nernst diffusion layer and improves the electromagnetic compatibility of the charging hardware.

[0082] In some embodiments, the current amplitude of the target disturbance current is ,in, For example, the target disturbance current amplitude can be selected from any value between 5% and 30% of the positive charging pulse current amplitude, or a range between any two values, such as selecting... , , , , , , Equal to any value, or select to , to Any range of intervals.

[0083] If the amplitude of the target perturbation current is less than 5% of the amplitude of the forward charging pulse, the microscopic electric field force and ion oscillation displacement generated by the target perturbation current are small and easily covered by the forward charging pulse, making it difficult to disturb the Nernst diffusion layer. If the amplitude of the target perturbation current is greater than 30% of the amplitude of the forward charging pulse, the excessive AC component causes the lithium battery to withstand a large instantaneous peak current during charging, leading to increased internal temperature rise and damage to battery life. The technical solution of this embodiment selects the amplitude of the target perturbation current between 5% and 30% of the current amplitude of the forward charging pulse. This effectively perturbs the Nernst diffusion layer while providing sufficient interfacial destructive force, without interfering with the charging process or causing additional significant temperature rise and ohmic heat loss.

[0084] The target disturbance duration during the positive charging pulse is: ,in, For example, the target disturbance duration of the target disturbance current can be selected as any value from 0s (excluding 0s) to 100s, or a range between any two values, such as 0.001s, 0.1s, 1s, 10s, 100s, etc., or any range from 1s to 10s, 10s to 100s, etc. The technical solution of this embodiment selects the target disturbance duration within the above range to ensure that high-frequency disturbances can be performed during charging, hindering the establishment of the concentration gradient.

[0085] The characteristic frequencies of the charge transfer process are electrochemical characteristic parameters reflecting the rate of charge transfer at the electrode or electrolyte interface within a lithium battery. In the Nyquist plot of an electrochemical impedance spectroscopy, the characteristic frequencies of the charge transfer process correspond to the inflection point frequencies representing charge transfer impedance in the mid-to-high frequency region.

[0086] In electrochemistry, charge transfer processes exhibit a certain degree of inertia and time delay. If the frequency of the target perturbation current is less than or equal to the characteristic frequency of the charge transfer process in a lithium battery, the rate of change of the target perturbation current is slower than the response speed of the interfacial charge transfer. Charge transfer impedance becomes the primary obstacle, and the perturbation energy of the target perturbation current is consumed in overcoming reaction resistance, failing to generate an effective electric field driving force for ion distribution. When the frequency of the target perturbation current is greater than the characteristic frequency of the charge transfer process, the high-frequency target perturbation current can penetrate the interfacial impedance barrier, accelerating charge transfer and perturbing the diffusion layer, thereby reducing the equivalent resistance of the double layer, perturbing the Nernst diffusion layer, and preventing the establishment of a stable concentration gradient.

[0087] The target disturbance current can be disturbed throughout the entire period of the positive charging pulse, or it can be disturbed for a portion of the period of the positive charging pulse. Therefore, the disturbance modes of the target disturbance current include full-cycle disturbance mode, lag disturbance mode, and synchronous partial disturbance mode, as detailed below: 1) Full-cycle perturbation mode: In some embodiments, applying a target perturbation current to the lithium battery during a forward charging pulse includes the following steps: controlling the transfer of the target perturbation current to the lithium battery during the forward charging pulse according to a preset first perturbation duration, wherein, , The duration of the first disturbance, The pulse width of the positive charging pulse.

[0088] First disturbance duration This refers to the duration for which the target disturbance current is continuously applied within one cycle of a positive charging pulse. Please refer to [link / reference]. Figure 5The target perturbation current continues from the beginning of the positive charging pulse until the end of the positive charging pulse. The perturbation time of the target perturbation current completely covers the pulse width of the entire positive charging pulse, providing uninterrupted interface micro-perturbation throughout the charging process. This ensures that the establishment of the micro-concentration gradient can be perturbed at any moment during the injection of the positive charging pulse, and the formation of the Nernst diffusion layer is perturbed throughout the process. This maximizes the suppression of concentration polarization accumulation and ensures that the negative electrode potential is above 0V throughout the entire positive charging phase.

[0089] 2) Lag disturbance mode: In some embodiments, applying a target perturbation current to the lithium battery during a forward charging pulse includes the following steps: during the period of the forward charging pulse, in response to the forward charging pulse experiencing a first charging duration, controlling the transfer of the target perturbation current to the lithium battery according to a preset second perturbation duration, wherein, , For the second disturbance duration, This is the first charging time.

[0090] First charging time This refers to the period after the start of the forward charging pulse, during which no target disturbance current is applied, and only pure charging occurs. Second disturbance duration. This refers to the duration of the first charging cycle. Then, the target disturbance current is applied.

[0091] Please see Figure 6 Among them, when the duration of the second disturbance is At that time, the duration of the second disturbance This refers to the duration of the first charging cycle. Then, the target disturbance current is applied and continues until the positive charging pulse ends.

[0092] Please see Figure 7 When the second disturbance duration At that time, the duration of the second disturbance This refers to the duration of the first charging cycle. Then, the target disturbance current is applied, and the period ends before the positive charging pulse ends.

[0093] Based on the physical laws governing battery polarization, the technical solution of this embodiment addresses the initial charging stage where the lithium-ion concentration on the negative electrode surface has not yet significantly decreased and a concentration gradient has not yet formed; therefore, no target perturbation current is applied initially. After the first charging period, as the concentration gradient begins to form significantly, the technical solution of this embodiment then superimposes the target perturbation current to suppress the formation of the concentration gradient, thereby reducing the consumption of ineffective energy.

[0094] 3) Synchronous partial perturbation mode: In some embodiments, applying a target perturbation current to the lithium battery during a forward charging pulse includes the following steps: during the period of the forward charging pulse, in response to the rising edge of the forward charging pulse, controlling the transmission of the target perturbation current to the lithium battery according to a preset third perturbation duration. , This is the duration of the third disturbance.

[0095] The rising edge refers to the instant when the current of the positive charging pulse jumps from zero to the target amplitude. The third disturbance duration refers to the duration for which the target disturbance current is applied, starting from the rising edge of the positive charging pulse.

[0096] Please see Figure 8 The technical solution of this embodiment starts applying a target disturbance current to the lithium battery the instant a positive charging pulse is applied. The high-frequency target disturbance current can quickly activate the low-resistance channel of the double-layer capacitor, buffer the transient impact of the large current on the interface, and prevent the negative electrode potential from dropping sharply at the moment of charging, such as dropping below 0V and causing initial lithium plating.

[0097] The technical solution of this embodiment introduces an adaptive triggering mechanism based on the battery's state of charge (SOC) before applying the target perturbation current during the forward charging pulse. In some embodiments, before applying the target perturbation current to the lithium battery during the forward charging pulse, the lithium battery charging method further includes the following steps: determining the current state of charge value of the lithium battery, and in response to the current state of charge value being within a preset state of charge range, proceeding to the step of applying the target perturbation current to the lithium battery during the forward charging pulse.

[0098] The current state of charge (SOC) is the ratio of the actual remaining capacity of a lithium battery to its rated capacity when fully charged. It is used to quantitatively assess the charge and discharge state of a lithium battery. Because the concentration distribution of lithium ions, the degree of lithium intercalation at the electrodes, and the interfacial impedance vary greatly at different SOCs, the current state of charge can reflect the current electrochemical stage of the lithium battery.

[0099] A preset state of charge (SOC) range refers to a pre-defined range that represents the SOC range of a lithium battery at a specific electrochemical stage. In some embodiments, the preset SOC range is... ,in, This is the value for a fully charged state. This refers to the current state of charge (SOC). For example, when the current SOC of a lithium battery is between 60% and 100%, lithium plating is likely to occur. Therefore, the technical solution of this embodiment sets the SOC range between 60% and 100% as a preset state of charge.

[0100] When a lithium battery is in the low SOC stage, there are a large number of vacancies in the negative electrode, making it easy for lithium ions to intercalate. Concentration polarization is small, and the negative electrode potential is above 0V, so high-frequency perturbation is not required. When the lithium battery enters the high SOC stage, lithium intercalation in the negative electrode tends to saturate, the interface impedance rises sharply, and polarization accumulation easily leads to the negative electrode potential approaching the 0V lithium plating critical point.

[0101] When the current state of charge value is less than When a lithium battery is in a low to medium state of charge, there are many lithium intercalation vacancies within the graphite anode. Lithium ions can smoothly intercalate into the anode bulk phase after crossing the interface from the electrolyte. At this time, the lithium ion concentration difference between the anode surface and the interior is small, and the anode potential is above 0V. When the current state of charge is equal to... The lithium battery is fully charged and requires no further disturbance.

[0102] Technical solution settings of this embodiment and To preset the state of charge range, when the current state of charge value is within the preset state of charge range, a target perturbation current is applied to the lithium battery during the positive charging pulse. In this way, when the negative electrode potential is about to drop below 0V, the high-frequency perturbation method can ensure that the negative electrode potential is maintained above 0V throughout the process, thus avoiding lithium plating.

[0103] Step S43: After the positive charging pulse ends, the lithium battery is depolarized.

[0104] Depolarization treatment refers to the operation of eliminating or mitigating polarization phenomena inside the battery after the positive charging pulse ends, especially eliminating polarization phenomena on the surface of the negative electrode. The technical solution of this embodiment performs depolarization treatment on the lithium battery after the positive charging pulse ends, which can eliminate the interface concentration gradient formed during the positive charging pulse, reduce concentration polarization, and actively intervene in and eliminate the reversible lithium accumulation that has been formed.

[0105] The technical solution of this embodiment superimposes a high-frequency target perturbation current during the forward charging pulse. By rapidly changing the direction or magnitude of the current at a microscopic level, it continuously agitates the ion distribution at the electrode interface, breaking up the concentration gradient before it forms. This perturbs the Nernst diffusion layer, preventing the establishment of a stable concentration gradient, reducing polarization and the formation of lithium dendrites, thereby improving the charging efficiency and lifespan of the lithium battery. Following the high-frequency microscopic perturbation, this embodiment performs a depolarization process. The high-frequency perturbation weakens the polarization basis, while the depolarization process removes residual polarization through natural diffusion or passive relaxation. The synergistic effect of these two processes allows lithium ions at the negative electrode interface to migrate in a timely manner, easily keeping the negative electrode potential above the lithium plating critical potential and preventing lithium plating during fast charging.

[0106] The depolarization process includes any one or a combination of applying a reverse discharge pulse to the lithium battery, subjecting the lithium battery to zero-current rest, and applying a target charging pulse to the lithium battery, wherein the current direction of the target charging pulse is consistent with the current direction of the forward charging pulse, and the current amplitude of the target charging pulse is less than the current amplitude of the forward charging pulse.

[0107] For example, within one charging cycle, the technical solution of this embodiment applies a reverse discharge pulse to the lithium battery, performs zero-current resting on the lithium battery, or applies a target charging pulse to the lithium battery after the positive charging pulse ends. For example, within one charging cycle, the technical solution of this embodiment applies a reverse discharge pulse to the lithium battery after the positive charging pulse ends, and performs zero-current resting on the lithium battery after the reverse discharge pulse ends. For example, within one charging cycle, the technical solution of this embodiment applies a reverse discharge pulse to the lithium battery after the positive charging pulse ends, and applies a target charging pulse to the lithium battery after the reverse discharge pulse ends. For example, within one charging cycle, the technical solution of this embodiment applies a reverse discharge pulse to the lithium battery after the positive charging pulse ends, performs zero-current resting on the lithium battery after the reverse discharge pulse ends, and applies a target charging pulse to the lithium battery after the zero-current resting. For example, within one charging cycle, the technical solution of this embodiment applies a reverse discharge pulse to the lithium battery after the positive charging pulse ends, applies a target charging pulse to the lithium battery after the reverse discharge pulse ends, and performs zero-current resting on the lithium battery after the target charging pulse ends.

[0108] For example, within one charging cycle, the technical solution of this embodiment performs a zero-current rest period on the lithium battery after the positive charging pulse ends, and after the zero-current rest period ends, a reverse discharge pulse or a target charging pulse is applied to the lithium battery. For example, within one charging cycle, the technical solution of this embodiment performs a zero-current rest period on the lithium battery after the positive charging pulse ends, and after the zero-current rest period ends, a reverse discharge pulse is applied to the lithium battery. For example, within one charging cycle, the technical solution of this embodiment performs a zero-current rest period on the lithium battery after the positive charging pulse ends, and after the zero-current rest period ends, a target charging pulse is applied to the lithium battery. For example, within one charging cycle, the technical solution of this embodiment performs a zero-current rest period on the lithium battery after the positive charging pulse ends, and after the zero-current rest period ends, a reverse discharge pulse is applied to the lithium battery, and after the reverse discharge pulse ends, a target charging pulse is applied to the lithium battery. For example, in one charging cycle, the technical solution of this embodiment performs zero-current rest on the lithium battery after the positive charging pulse ends, applies a target charging pulse to the lithium battery after the zero-current rest ends, and applies a reverse discharge pulse to the lithium battery after the target charging pulse ends.

[0109] For example, within one charging cycle, the technical solution of this embodiment applies a target charging pulse to the lithium battery after the positive charging pulse ends, and then applies a reverse discharging pulse or performs zero-current resting on the lithium battery after the target charging pulse ends. For example, within one charging cycle, the technical solution of this embodiment applies a target charging pulse to the lithium battery after the positive charging pulse ends, and then applies a reverse discharging pulse to the lithium battery after the target charging pulse ends. For example, within one charging cycle, the technical solution of this embodiment applies a target charging pulse to the lithium battery after the positive charging pulse ends, and then performs zero-current resting on the lithium battery after the target charging pulse ends. For example, within one charging cycle, the technical solution of this embodiment applies a target charging pulse to the lithium battery after the positive charging pulse ends, and then applies a reverse discharging pulse to the lithium battery after the target charging pulse ends, and then performs zero-current resting on the lithium battery after the reverse discharging pulse ends. For example, within one charging cycle, the technical solution of this embodiment applies a target charging pulse to the lithium battery after the positive charging pulse ends, and then performs zero-current resting on the lithium battery after the target charging pulse ends, and then applies a reverse discharging pulse to the lithium battery.

[0110] The following descriptions of some embodiments of this application regarding applying a reverse discharge pulse to a lithium battery, subjecting the lithium battery to zero-current rest, and applying a target charging pulse to the lithium battery are as follows: 1) Depolarization treatment involves applying a reverse discharge pulse to the lithium battery.

[0111] In some embodiments, depolarization is performed by applying a reverse discharge pulse to the lithium battery. The reverse discharge pulse is a current signal that briefly discharges from the lithium battery after a forward charging pulse has ended. The current direction of the reverse discharge pulse is opposite to that of the forward charging pulse. See also... Figure 9 The technical solution of this embodiment applies a square-wave reverse discharge pulse to the lithium battery after the forward charging pulse ends. Please refer to [link / reference]. Figure 10 The technical solution of this embodiment applies a sinusoidal reverse discharge pulse to the lithium battery after the forward charging pulse ends. This reverse discharge pulse, by instantaneously reversing the electric field direction, actively generates a reverse electric field force at the interface between the negative electrode and the electrolyte. This forces lithium ions accumulated on the surface of the negative electrode but not yet embedded in the bulk phase back into the electrolyte or accelerates their diffusion into the negative electrode particles, thereby breaking the concentration gradient and causing the negative electrode potential to rise and move away from the 0V lithium plating critical line.

[0112] In some embodiments, the current amplitude of the reverse discharge pulse is ,in, , , This is an inverse proportionality coefficient. If... If the value is less than -1, the current of the reverse discharge pulse is greater than the current of the forward charging pulse. This will bring serious negative effects to the system. For example, the reverse discharge pulse will cause a severe ohmic heating effect, which will cause the internal temperature of the battery to deteriorate rapidly. An excessive reverse electric field will over-consume the effective charge that has been charged, resulting in a significant decrease in charging efficiency.

[0113] The technical solution of this embodiment is... By selecting a reverse proportional coefficient within the range to construct a reverse discharge pulse, it is ensured that sufficient reverse depolarization electric field force is provided without triggering additional serious thermal runaway risks, and the net injected capacity is positive throughout the overall charging cycle, maintaining the high efficiency of fast charging.

[0114] In some embodiments, the pulse width of the reverse discharge pulse is ,in, If the pulse width of the reverse discharge pulse is less than 0.5% of the pulse width of the forward charge pulse, the short reverse electric field duration is insufficient to displace the lithium ions accumulated on the negative electrode surface, thus failing to effectively eliminate concentration polarization. If the pulse width of the reverse discharge pulse is greater than 50% of the pulse width of the forward charge pulse, the discharge depolarization time is longer, which can lead to the lithium battery discharging more electricity than it charges during a complete charge-discharge cycle (resulting in a negative net charge).

[0115] The technical solution of this embodiment is... By selecting the pulse width of the reverse discharge pulse, it is ensured that the reverse discharge pulse has a sufficient effective duration to establish a stable reverse electric field, so that lithium ions at the interface can be truly pushed back into the electrolyte, improving the depolarization effect and avoiding the power loss caused by over-discharge, thus achieving the optimal balance between depolarization effect and charging efficiency.

[0116] 2) Depolarization treatment involves zero-current static treatment of the lithium battery.

[0117] In some embodiments, the depolarization process involves subjecting the lithium battery to zero-current resting, the resting time being [length missing]. ,in, .

[0118] Zero-current resting time refers to the period after the positive charging pulse ends when the lithium battery stops charging and discharging. Please refer to [link / reference]. Figure 11 The technical solution of this embodiment performs zero-current resting on the lithium battery after the positive charging pulse ends. Without inputting or extracting energy from the lithium battery, this technical solution relies on the natural diffusion and electrochemical relaxation of lithium ions inside the battery to eliminate the concentration polarization accumulated during positive charging, thereby making the ion concentration at the electrode interface tend to become uniform again.

[0119] If the resting time width of zero current is less than The extremely short time is insufficient for lithium ions to undergo meaningful physical diffusion and migration, and the interface concentration gradient still exists. If the resting time at zero current is greater than... This can easily prolong the overall charging cycle, negating the benefits of fast charging.

[0120] The technical solution of this embodiment is... The range is selected for the resting time width of zero current resting. High-frequency disturbances destroy the Nernst diffusion layer during charging. Zero current resting utilizes natural diffusion and electrochemical relaxation during the gap to eliminate the concentration polarization accumulated during forward charging, so that the ion concentration at the electrode interface tends to be uniform again, avoiding lithium plating.

[0121] 3) Depolarization treatment involves applying a target charging pulse to the lithium battery.

[0122] In some embodiments, the depolarization process involves applying a target charging pulse to the lithium battery, the target charging pulse having a current amplitude of [value missing]. ,in, , ,in, This refers to a small current coefficient. The target charging pulse is a pulse applied to the lithium battery during the depolarization phase, with the same current direction as the forward charging pulse but a significantly reduced current amplitude. Please refer to [link / reference]. Figure 12 The technical solution of this embodiment does not cut off the current or perform reverse discharge during the depolarization stage. Instead, it continues to inject charge into the lithium battery with a small current, maintaining the electric field activity at the interface and continuing to charge without causing new significant polarization.

[0123] If the small current coefficient is greater than 0.5, the current amplitude of the target charging pulse is at least half the current amplitude of the forward charging pulse, which is relatively large. This not only fails to eliminate concentration polarization but also further exacerbates polarization accumulation, preventing the negative electrode potential from effectively recovering. The technical solution of this embodiment... By selecting a small current coefficient, the small current provides a tiny driving force that is insufficient to form a new concentration gradient, but it can utilize natural diffusion to smooth out the existing concentration difference, achieving smooth, gentle, and continuous depolarization, effectively protecting the battery interface.

[0124] In some embodiments, the pulse width of the target charging pulse is ,in, If the pulse width of the target charging pulse is less than... A short time is insufficient for lithium ions to complete meaningful diffusion and migration within the negative electrode phase; the interface concentration difference still exists, and the actual depolarization effect is not achieved. If the pulse width of the target charging pulse is greater than... The duration of a small current is relatively long, which is not conducive to improving charging efficiency and can easily prolong the overall charging cycle.

[0125] The technical solution of this embodiment is... Selecting the pulse width of the target charging pulse range not only ensures that the small current has enough time to establish a stable electrochemical relaxation process, helping lithium ions to complete meaningful diffusion and migration within the negative electrode phase, but also improves charging efficiency, achieving an optimal balance between polarization suppression and fast charging efficiency.

[0126] It is understandable that applying a positive charging pulse to a lithium battery does not need to be done throughout the entire charging cycle of the lithium battery. The pulse charging strategy provided by the technical solution of this embodiment (i.e., a synergistic strategy including a positive charging pulse, superimposed target perturbation current, and depolarization treatment) can be used as an independent charging stage and flexibly superimposed with conventional charging methods for combined use to match the electrochemical characteristics of the battery under different states of charge, thereby achieving an optimal balance between efficiency and lifespan.

[0127] In some embodiments, during the initial charging phase, a conventional constant-current charging method is used to charge the lithium battery to a first specified SOC, for example, 0% to 60%. At this point, there are sufficient lithium intercalation vacancies in the negative electrode, resulting in a low risk of polarization. Subsequently, the system switches to the pulse charging strategy provided in this embodiment, applying a positive charging pulse to the lithium battery and superimposing a target perturbation current during this pulse to charge the battery to a second specified SOC or a preset voltage threshold. Finally, the system transitions to a conventional constant-current and constant-voltage charging phase until fully charged. This embodiment effectively blocks the establishment of a concentration gradient by utilizing the high-frequency perturbation of the target perturbation current in the polarization-prone middle section, and ensures full-charge accuracy using constant-voltage charging at the end.

[0128] In other embodiments, during the initial charging phase, the battery is first charged to a third specified SOC using a conventional constant current rate, for example, the third specified SOC being 0% to 60%; subsequently, the pulse charging strategy provided by this embodiment is used to charge the battery to 100%. This embodiment abandons the traditional high SOC end-current-reducing constant voltage process, and utilizes the pulse charging strategy provided by this embodiment to enable the lithium battery to withstand a large pulse current in the high SOC range without lithium plating.

[0129] In some embodiments, applying a positive charging pulse to a lithium battery to charge the lithium battery based on the positive charging pulse includes the following steps: determining the current state of charge (SOC) value of the lithium battery, and applying a positive charging pulse to the lithium battery in response to the current SOC value being within a target SOC range to charge the lithium battery based on the positive charging pulse.

[0130] The target state of charge (SOC) range is defined by the designer based on engineering experience. For example, the target SOC range is 60% to 80%. When the current SOC value is between 60% and 80%, the technical solution of this embodiment begins to apply a positive charging pulse to the lithium battery, allowing the lithium battery to be charged based on the positive charging pulse. When the current SOC value has not reached 60% to 80%, the lithium battery is charged using a conventional charging method.

[0131] When a lithium battery is in a low state of charge (e.g., 0%~60%), there are numerous lithium intercalation vacancies in the negative electrode, resulting in minimal resistance to lithium-ion diffusion and a negative electrode potential above 0V. At this stage, conventional constant current charging can achieve the most efficient charge injection. When the lithium battery's state of charge reaches 60%~80%, lithium intercalation in the negative electrode bulk phase tends to saturate, increasing the resistance to lithium-ion diffusion into the negative electrode. Macroscopic concentration polarization begins to accumulate exponentially, and the negative electrode potential approaches or even falls below the 0V lithium plating critical point. The technical solution in this embodiment precisely inserts a forward charging pulse within the target state of charge range, intervening at the dangerous inflection point where polarization begins to deteriorate rapidly. Through the depolarization gap inherent in the pulse, it forcibly interrupts the solidification of the concentration gradient, pulling the negative electrode potential back to a safe zone before it sinks, thus avoiding microscopic lithium plating in the mid-to-high SOC range.

[0132] In some embodiments, the method further includes: stopping the application of positive charging pulses to the lithium battery in response to the current state of charge (SOC) of the lithium battery reaching a state of charge termination value. The state of charge termination value is customized by the designer based on engineering experience; for example, the state of charge termination value is 100%. When the lithium battery is fully charged or has reached the desired charge level, the technical solution of this embodiment stops applying positive charging pulses to the lithium battery to avoid damaging the lithium battery by continuing to charge.

[0133] In response to the current state of charge (SOC) value of the lithium battery being within a target SOC range, a positive charging pulse is applied to the lithium battery to charge it based on the positive charging pulse, comprising the following steps: in response to the current SOC value of the lithium battery being within a target SOC range, determining the current amplitude corresponding to the target SOC range as the current amplitude of the positive charging pulse; applying the positive charging pulse to the lithium battery to charge it based on the positive charging pulse.

[0134] Lithium-ion batteries exhibit significant differences in negative electrode lithium intercalation vacancies, solid-phase diffusion resistance, and polarization limits at different State of Charge (SOC) stages. The technical solution in this embodiment determines a specific current amplitude corresponding to the current SOC range. In the low / medium SOC range, where the lithium battery has strong tolerance, this embodiment allocates a large current amplitude; in the high-SOC, high-risk range, this embodiment automatically allocates a small current amplitude. This avoids the negative electrode potential dropping below 0V due to forcibly injecting a large current at the end, while ensuring that charging is performed at the maximum permissible current at each stage under safe conditions, thus improving charging efficiency.

[0135] In some embodiments, in response to the current state of charge (SBC) value of the lithium battery being within a target SBC range, determining the current amplitude of the forward charging pulse corresponding to the target SBC range includes the following steps: in response to the current SBC value of the lithium battery being greater than a first SBC value and less than or equal to a second SBC value, selecting a first current amplitude as the current amplitude of the forward charging pulse.

[0136] For example, the first state of charge (SOC) value is 0%, and the second SOC value is 30%. When the current SOC value of the lithium battery is between 0% and 30%, the technical solution of this embodiment selects the first current amplitude. Let be the current amplitude of the positive charging pulse, where , The first current amplitude, The current amplitude of the positive charging pulse. For example, the first current coefficient, .

[0137] In some embodiments, in response to the current state of charge (SBC) value of the lithium battery being within a target SBC range, determining the current amplitude corresponding to the target SBC range as the current amplitude of the forward charging pulse includes the following steps: in response to the current SBC value of the lithium battery being greater than a second SBC value and less than or equal to a third SBC value, selecting a second current amplitude as the current amplitude of the forward charging pulse, wherein the second current amplitude is less than the first current amplitude.

[0138] For example, the second state of charge (SOC) value is 30%, and the third SOC value is 50%. When the current SOC value of the lithium battery is between 30% and 50%, the technical solution of this embodiment selects the second current amplitude. Let be the current amplitude of the positive charging pulse, where , This is the second current amplitude. The second current coefficient, For example, the second current coefficient It is 0.8.

[0139] In some embodiments, in response to the current state of charge (SBC) value of the lithium battery being within a target SBC range, determining the current amplitude corresponding to the target SBC range as the current amplitude of the forward charging pulse includes the following steps: in response to the current SBC value of the lithium battery being greater than a third SBC value and less than or equal to a fourth SBC value, selecting a third current amplitude as the current amplitude of the forward charging pulse, wherein the third current amplitude is less than a second current amplitude.

[0140] For example, the third state of charge (SOC) value is 50%, and the fourth SOC value is 80%. When the current SOC value of the lithium battery is between 50% and 80%, the technical solution of this embodiment selects the third current amplitude. Let be the current amplitude of the positive charging pulse, where , This is the third current amplitude. The third current coefficient, For example, the third current coefficient It is 0.4.

[0141] In some embodiments, in response to the current state of charge (SBC) value of the lithium battery being within a target SBC range, determining the current amplitude corresponding to the target SBC range as the current amplitude of the forward charging pulse includes the following steps: in response to the current SBC value of the lithium battery being greater than a fourth SBC value and less than or equal to a fifth SBC value, selecting a fourth current amplitude as the current amplitude of the forward charging pulse, wherein the fourth current amplitude is less than a third current amplitude.

[0142] For example, the fourth state of charge (SOC) is 80%, and the fifth SOC is 100%. When the current SOC of the lithium battery is between 80% and 100%, the technical solution of this embodiment selects the fourth current amplitude. Let be the current amplitude of the positive charging pulse, where , This is the fourth current amplitude. The fourth current coefficient, For example, the fourth current coefficient It is 0.1.

[0143] The technical solution of this embodiment employs a stepped current reduction strategy based on the current state of charge (SOC). In the low SOC range, a large current is maintained to seize charging time, while in the high SOC range, the current is significantly reduced to ensure charging safety. This achieves maximum charging efficiency without preventing lithium plating. As the charging process progresses, lithium intercalation saturation at the negative electrode leads to a sharp increase in solid-phase diffusion resistance. The stepped current reduction actively lowers the lithium-ion migration rate, ensuring that lithium ions always match the declining diffusion capacity. This, combined with depolarization treatment, helps reduce the risk of lithium plating.

[0144] The embodiments and comparative examples are given below to illustrate the embodiments of this application in more detail, as follows: Comparative Example 1: Step 1: The lithium battery has a SOC of 0% before charging. Charge the lithium battery with a constant current of 10C DC. Step 2: Stop charging when the lithium battery reaches 100% SOC.

[0145] Example 1-1: If the lithium battery has a state of charge (SOC) of 0% before charging, perform the following steps: Step 1: Set the current amplitude of the forward charging pulse to 10C, the pulse width to 1s, and the waveform to a square wave; Step 2: Apply a reverse discharge pulse to the lithium battery. The current amplitude of the reverse discharge pulse is -5C and the pulse width is 0.28s. Steps 1 and 2 form a step execution unit. This step execution unit is executed in each charging cycle until the lithium battery capacity reaches 100% SOC, at which point charging is stopped.

[0146] Examples 1-2: If the lithium battery has a state of charge (SOC) of 0% before charging, perform the following steps: Step 1: Set the current amplitude of the forward charging pulse to 10C, the pulse width to 1s, and the waveform to a square wave; Step 2: During the positive charging pulse, a target disturbance current is superimposed. The frequency of the target disturbance current is 10kHz, the pulse width is 0.5s, and the current amplitude is 1.8C.

[0147] Step 3: Apply a reverse discharge pulse to the lithium battery. The current amplitude of the reverse discharge pulse is -5C and the pulse width is 0.28s. Steps 1, 2 and 3 form a step execution unit. This step execution unit is executed in each charging cycle until the lithium battery capacity reaches 100% SOC, at which point charging is stopped.

[0148] Based on Examples 1-2, Examples 1-3 to 1-40 were designed respectively, wherein the SOC of any of Examples 1-3 to 1-40 is 0% before charging. In Example 1-2, the current amplitude of the forward charging pulse... Pulse width Among them, the current amplitude of the forward charging pulse The range of values ​​is The pulse width range is .

[0149] Since the current amplitude and pulse width of the forward charging pulse affect the current amplitude and pulse width of the reverse discharging pulse, zero-current rest, and target charging pulse, respectively, based on Examples 1-2, the current amplitude of the target disturbance current can be obtained. The range of values ​​is Target perturbation duration The range of values ​​is ,frequency The range of values ​​is The current amplitude of the reverse discharge pulse. The range of values ​​is The pulse width range is Zero-current settling time width The range of values ​​is The current amplitude of the target charging pulse. The range of values ​​is The pulse width range is .

[0150] Based on the value range of the above parameters, the parameters for Examples 1-3 to 1-40 are designed as shown in Table 1: Table 1

[0151] This application also includes Embodiments 1-41 to 1-45, as follows: Examples 1-41: The lithium battery has a state of charge (SOC) of 50% before charging. Perform the following steps: Step 1: Set the current amplitude of the forward charging pulse to 10C, the pulse width to 1s, and the waveform to a square wave; Step 2: During the positive charging pulse, a target disturbance current is superimposed. The frequency of the target disturbance current is 10kHz, the pulse width is 0.5s, and the current amplitude is 1.8C.

[0152] Step 3: Apply a reverse discharge pulse to the lithium battery. The current amplitude of the reverse discharge pulse is -5C and the pulse width is 0.28s. Steps 1, 2 and 3 form a step execution unit. This step execution unit is executed in each charging cycle until the lithium battery capacity reaches 100% SOC, at which point charging is stopped.

[0153] Following the method described in Examples 1-41, the parameters for Examples 1-42 to 1-45 are set as shown in Table 2: Table 2

[0154] Examples 1-46: If the lithium battery has a state of charge (SOC) of 0% before charging, perform the following steps: Step 1.1: Set the current amplitude of the forward charging pulse to 10C and the pulse width to 1s; Step 1.2: During the positive charging pulse, a target disturbance current is superimposed. The frequency of the target disturbance current is 10kHz, the pulse width is 0.5s, and the current amplitude is 1.8C. Step 1.3: Apply a reverse discharge pulse to the lithium battery. The current amplitude of the reverse discharge pulse is -5C and the pulse width is 0.28s. Steps 1.1, 1.2 and 1.3 form a step execution unit. This step execution unit is executed in each charging cycle until the lithium battery capacity is charged to 30% SOC.

[0155] then: Step 2.1: Set the current amplitude of the forward charging pulse to 6C and the pulse width to 1s; Step 2.2: During the positive charging pulse, a target disturbance current is superimposed. The frequency of the target disturbance current is 10kHz, the pulse width is 0.5s, and the current amplitude is 1.8C. Step 2.3: Apply a reverse discharge pulse to the lithium battery. The current amplitude of the reverse discharge pulse is -5C and the pulse width is 0.28s. Steps 2.1, 2.2 and 2.3 form a step execution unit. This step execution unit is executed in each charging cycle until the capacity of the lithium battery is charged from 30% to 50% SOC.

[0156] then: Step 3.1: Set the current amplitude of the forward charging pulse to 4C and the pulse width to 1s; Step 3.2: During the positive charging pulse, a target disturbance current is superimposed. The frequency of the target disturbance current is 10kHz, the pulse width is 0.5s, and the current amplitude is 1.8C. Step 3.3: Apply a reverse discharge pulse to the lithium battery. The current amplitude of the reverse discharge pulse is -5C and the pulse width is 0.28s. Steps 3.1, 3.2 and 3.3 form a step execution unit. This step execution unit is executed in each charging cycle until the capacity of the lithium battery is charged from 50% to 80% SOC.

[0157] then: Step 4.1: Set the current amplitude of the forward charging pulse to 1C and the pulse width to 1s; Step 4.2: During the positive charging pulse, a target disturbance current is superimposed. The frequency of the target disturbance current is 10kHz, the pulse width is 0.5s, and the current amplitude is 1.8C. Step 4.3: Apply a reverse discharge pulse to the lithium battery. The current amplitude of the reverse discharge pulse is -5C and the pulse width is 0.28s. Steps 4.1, 4.2 and 4.3 form a step execution unit. This step execution unit is executed in each charging cycle until the capacity of the lithium battery is charged from 80% to 100% SOC.

[0158] at last: When the lithium battery reaches 100% SOC, charging stops.

[0159] As described in Examples 1-1 to 1-46 and the comparative examples, the above lithium batteries were subjected to negative electrode potential monitoring and cycle life testing. The results are shown in Table 3. Table 3

[0160] Table 3 provides three key indicators: negative electrode potential, charging time, and cycle life. A higher negative electrode potential indicates better performance in this embodiment. A negative electrode potential below 0V indicates that lithium plating has occurred, and the lithium battery is damaged. Shorter charging time is better. A higher cycle life is better.

[0161] Compared to the comparative examples, Examples 1-1 to 1-46 all included a depolarization process, which resulted in the negative electrode potential of the lithium battery being higher than 0V (except for Examples 1-8) and significantly improved. This prevented the negative electrode potential from approaching or falling below the lithium plating potential, thus avoiding lithium plating inside the lithium battery. Consequently, it suppressed the occurrence of side reactions and the rapid consumption of electrolyte, thereby improving cycle life.

[0162] Compared to Example 1-1, Example 1-2 adds a target perturbation current process on the basis of adding depolarization treatment. Therefore, the embodiments of this application introduce a high-frequency perturbation method, and the negative electrode potential of the lithium battery is significantly increased compared to the method without adding high-frequency perturbation, from 7mV to 12mV, and the cycle life is increased from 1105 to 1305. Therefore, through micro-stirring, concentration polarization is blocked, and the concentration gradient that has not yet formed is physically dispersed, so that lithium ions cannot accumulate at the interface. At the same time, high-frequency perturbation prevents the accumulation of destructive polarization, which greatly delays the nucleation and growth of lithium dendrites.

[0163] From Examples 1-3 to Examples 1-8, it can be seen that the current amplitude of the forward charging pulse... The range of values ​​is In the case of, or, in the case where the pulse width of the forward charging pulse is within the range of, Under these conditions, both the negative electrode potential and cycle life are significantly improved. As shown in Examples 1-8, when the pulse width of the forward charging pulse is greater than 100s, the negative electrode potential drops below 0V, lithium plating occurs, and the cycle life drops sharply to below 700 cycles, verifying that the pulse width of the forward charging pulse must be less than the Weber diffusion characteristic time constant.

[0164] Through Examples 1-9 to 1-12, it can be seen that as the frequency increases from 100Hz to 500Hz, the negative electrode potential increases and the lifetime increases, indicating that the frequency needs to be greater than 500Hz to effectively disturb the Nernst diffusion layer; in the frequency range of 500Hz to 30kHz, the higher the frequency, the better the disturbance effect, but the improvement decreases marginally.

[0165] As can be seen from Examples 1-13 to 1-16, the larger the disturbance amplitude, the higher the negative electrode potential and the longer the lifespan. However, after exceeding 30%, the marginal benefit decreases and it is easy to cause additional temperature rise. Therefore, comprehensive consideration is required in engineering.

[0166] As can be seen from Examples 1-17 to 1-20, the larger the perturbation width, the higher the negative electrode potential, the longer the lifespan, and the better the effect.

[0167] Examples 1-21 to 1-27 show that when the pulse width of the reverse discharge pulse is less than 0.5% of the pulse width of the forward charging pulse, the reverse electric field effect time is too short to effectively depolarize. Within the range of 0.5% to 28% pulse width of the reverse discharge pulse, the negative electrode potential and lifespan improve with increasing width. When the pulse width of the reverse discharge pulse is greater than 28%, the depolarization effect is better, but the charging time is significantly prolonged, resulting in a trade-off between depolarization benefits and charging speed. A larger reverse amplitude results in a stronger depolarization effect, but it also prolongs the charging time. The reverse amplitude can be close to or even slightly larger than the forward amplitude; as long as the reverse effect time is short enough, the net cycle charge remains positive, the battery can still be fully charged, and better lifespan performance is achieved.

[0168] As can be seen from Examples 1-28 to 1-32, by introducing high-frequency perturbation and zero-current static mode, the negative electrode potential of lithium battery is significantly increased compared to the mode without high-frequency perturbation. Therefore, by micro-stirring, concentration polarization is blocked, and the unformed concentration gradient is physically dispersed, preventing lithium ions from accumulating at the interface. At the same time, high-frequency perturbation prevents the accumulation of destructive polarization, which greatly delays the nucleation and growth of lithium dendrites.

[0169] As can be seen from Examples 1-33 to 1-40, by introducing high-frequency perturbation and low-current depolarization, the negative electrode potential of the lithium battery is significantly increased compared to the method without adding high-frequency perturbation. Therefore, by micro-stirring, concentration polarization is blocked, and the unformed concentration gradient is physically dispersed, preventing lithium ions from accumulating at the interface. At the same time, high-frequency perturbation prevents the accumulation of destructive polarization, which greatly delays the nucleation and growth of lithium dendrites.

[0170] Through Examples 1-41 to 1-45, it can be seen that in the low to medium SOC range (0-80%), under the synergistic effect of high-frequency disturbance and reverse discharge, the negative electrode potential can be stably maintained above 11mV, and the cycle life can be maintained above 1280 cycles.

[0171] As can be seen from Examples 1-46, Examples 1-46 adopt a four-stage stepped current reduction strategy (10C→6C→4C→1C), with different current amplitudes matched in each SOC range. While ensuring an extremely high negative electrode potential (18mV, far from the lithium plating boundary), the longest cycle life of 1600 cycles is achieved.

[0172] Please see Figure 13 , Figure 13 This is a schematic diagram of a charging control device provided in some embodiments of this application. The charging control device 12 includes one or more processors 121 and a memory 122. The memory 122 is connected to one or more processors 121, for example, via a bus.

[0173] Processor 121 is configured to support the charging control device in performing the corresponding functions in the methods described in the above method embodiments. The processor may be a central processing unit (CPU), a network processor (NP), a hardware chip, or any combination thereof. The aforementioned hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The aforementioned PLD may be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof.

[0174] Memory 122 is used to store program code, etc. Memory may include volatile memory (VM), such as random access memory (RAM); memory may also include non-volatile memory (NVM), such as read-only memory (ROM), flash memory, hard disk drive (HDD), or solid-state drive (SSD); memory may also include combinations of the above types of memory.

[0175] The memory 122 can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules, such as the program instructions / modules corresponding to the lithium battery charging method in this embodiment. The processor executes various functional applications and data processing of the lithium battery charging method by running the non-volatile software programs, instructions, and modules stored in the memory, thereby realizing the functions of the lithium battery charging method provided in the above embodiment. The memory 122 may include a program storage area and a data storage area. The program storage area may store the operating system and at least one application program required for a function. The data storage area may store data created based on the use of the lithium battery charging method, etc.

[0176] The one or more modules are stored in the memory. When executed by the one or more processors, they perform the lithium battery charging method in any of the above method embodiments. For example, they perform the method steps described in the above method embodiments to realize the functions of the modules described in the above device embodiments.

[0177] Some embodiments of this application also provide a computer-readable storage medium storing a computer program, the computer program including program instructions that, when executed by a charging control device, cause the charging control device to perform the method described in the foregoing embodiments.

[0178] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0179] The above-disclosed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Therefore, any equivalent variations made in accordance with the claims of this application shall still fall within the scope of this application.

[0180] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of this application as described above, which are not provided in detail for the sake of brevity; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for charging a lithium battery, characterized in that, include: A positive charging pulse is applied to the lithium battery so that the lithium battery is charged based on the positive charging pulse; During the positive charging pulse, a target perturbation current is applied to the lithium battery, the frequency of which is greater than the characteristic frequency of the charge transfer process in the lithium battery; After the positive charging pulse ends, the lithium battery is subjected to depolarization treatment.

2. The method according to claim 1, characterized in that, The pulse width of the forward charging pulse is greater than the characteristic time constant of the charge transfer process in the lithium battery and less than the characteristic time constant of the Weber diffusion process. The characteristic time constants of the charge transfer process and the Weber diffusion process are both obtained by electrochemical impedance spectroscopy of the lithium battery.

3. The method according to claim 1, characterized in that, The current amplitude of the forward charging pulse is ,in, ; and / or, The pulse width of the forward charging pulse is ,in, ; and / or, The current waveform of the positive charging pulse is a sine wave, square wave, triangle wave, or sawtooth wave.

4. The method according to claim 1, characterized in that, The frequency of the target disturbance current is ,in, ; and / or, The current amplitude of the target disturbance current is ,in, , , The current amplitude of the positive charging pulse; and / or, The target disturbance current during the positive charging pulse has a target disturbance duration of [duration]. ,in, , , The pulse width of the positive charging pulse; and / or, The current waveform of the target disturbance current is a sine wave, square wave, triangular wave, or sawtooth wave.

5. The method according to claim 1, characterized in that, Applying a target perturbation current to the lithium battery during the forward charging pulse includes: According to a preset first disturbance duration, during the positive charging pulse, the target disturbance current is controlled to be transmitted to the lithium battery, wherein, , The duration of the first disturbance. The pulse width of the positive charging pulse; or, During the period of the positive charging pulse, in response to the positive charging pulse experiencing a first charging duration, the target disturbance current is controlled to be transmitted to the lithium battery according to a preset second disturbance duration, wherein, , The duration of the second disturbance. For the first charging duration; or, During the period of the positive charging pulse, in response to the rising edge of the positive charging pulse, the target disturbance current is controlled to be transmitted to the lithium battery according to a preset third disturbance duration. , The duration of the third disturbance.

6. The method according to claim 1, characterized in that, Before applying the target perturbation current to the lithium battery during the positive charging pulse, the method further includes: Determine the current state of charge (SOC) value of the lithium battery; In response to the current state of charge value being within a preset state of charge range, the step of applying a target disturbance current to the lithium battery during the positive charging pulse is initiated.

7. The method according to claim 6, characterized in that, The preset state of charge range is: ,in, This is the value for a fully charged state. This represents the current state of charge.

8. The method according to claim 1, characterized in that, The depolarization process includes any one or a combination of applying a reverse discharge pulse to the lithium battery, subjecting the lithium battery to zero-current rest, and applying a target charging pulse to the lithium battery, wherein the current direction of the target charging pulse is consistent with the current direction of the forward charging pulse, and the current amplitude of the target charging pulse is less than the current amplitude of the forward charging pulse.

9. The method according to claim 8, characterized in that, The depolarization process includes applying a reverse discharge pulse to the lithium battery; The current amplitude of the reverse discharge pulse is ,in, , , , The current amplitude of the positive charging pulse; and / or, The pulse width of the reverse discharge pulse is ,in, , , The pulse width of the positive charging pulse.

10. The method according to claim 8, characterized in that, The depolarization treatment includes subjecting the lithium battery to zero-current resting, the resting time being [duration missing]. ,in, , , The pulse width of the positive charging pulse.

11. The method according to claim 8, characterized in that, The depolarization process includes applying a target charging pulse to the lithium battery, wherein the current amplitude of the target charging pulse is [value missing]. ,in, , , , The current amplitude of the positive charging pulse; and / or, The pulse width of the target charging pulse is ,in, , , The pulse width of the positive charging pulse.

12. The method according to claim 1, characterized in that, The step of applying a positive charging pulse to the lithium battery to charge the lithium battery based on the positive charging pulse includes: Determine the current state of charge (SOC) value of the lithium battery; In response to the current state of charge (SOC) of the lithium battery being within the target SOC range, a positive charging pulse is applied to the lithium battery to charge it based on the positive charging pulse.

13. The method according to claim 12, characterized in that, The step of applying a positive charging pulse to the lithium battery in response to the current state of charge (SOC) value of the lithium battery being within the target SOC range, so that the lithium battery is charged based on the positive charging pulse, includes: In response to the current state of charge of the lithium battery being within the target state of charge range, the current amplitude corresponding to the target state of charge range is determined to be the current amplitude of the forward charging pulse. The positive charging pulse is applied to the lithium battery so that the lithium battery is charged based on the positive charging pulse.

14. The method according to claim 13, characterized in that, The step of determining the current amplitude corresponding to the target state of charge range as the current amplitude of the forward charging pulse in response to the current state of charge value of the lithium battery being within the target state of charge range includes: In response to the current state of charge value of the lithium battery being greater than the first state of charge value and less than or equal to the second state of charge value, a first current amplitude value is selected as the current amplitude value of the forward charging pulse. In response to the current state of charge value of the lithium battery being greater than the second state of charge value and less than or equal to the third state of charge value, a second current amplitude is selected as the current amplitude of the forward charging pulse, wherein the second current amplitude is less than the first current amplitude. In response to the current state of charge value of the lithium battery being greater than the third state of charge value and less than or equal to the fourth state of charge value, a third current amplitude is selected as the current amplitude of the forward charging pulse, wherein the third current amplitude is less than the second current amplitude. In response to the current state of charge (SOC) value of the lithium battery being greater than the fourth SOC value and less than or equal to the fifth SOC value, a fourth current amplitude is selected as the current amplitude of the forward charging pulse, wherein the fourth current amplitude is less than the third current amplitude.

15. A charging control device, characterized in that, The device includes a memory and a processor, the memory being connected to the processor, the processor being configured to execute one or more computer programs stored in the memory, the processor causing the charging control device to implement the lithium battery charging method as described in any one of claims 1-14 when executing the one or more computer programs.

16. A lithium battery device, characterized in that, Includes the charging control device as described in claim 15.

17. An electrical appliance, characterized in that, Includes the lithium battery device as described in claim 16.

18. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, the computer program including program instructions that, when executed by a processor, cause the processor to perform the lithium battery charging method as described in any one of claims 1-14.

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