Pulse repair charging method for inhibiting lithium precipitation of echelon utilization battery, battery system and charging control equipment
By introducing a pulse repair intervention during the charging process, combined with adaptive adjustment of battery parameters, the problem of lithium plating in secondary batteries was solved, resulting in extended battery life, improved safety, and enhanced charging and discharging efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-23
- Publication Date
- 2026-04-07
AI Technical Summary
Lithium plating is prone to occur during the charging process of batteries used in cascaded applications, which leads to a decrease in battery cycle stability and safety hazards. Existing pulse discharge repair methods cannot effectively suppress lithium plating and must be performed after charging is completed, resulting in incomplete repair.
By introducing a pulse repair intervention during the charging process, lithium plating is suppressed through a set charging current variation pattern and pulse discharge, including multiple repair pulses and constant current charging, combined with adaptive adjustment of battery parameters.
It significantly extends battery life, improves safety and charge/discharge efficiency, reduces battery capacity decay, improves the stability of the negative electrode SEI film, enhances overall battery performance, and possesses economic efficiency and adaptive potential.
Smart Images
Figure CN121812795A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of battery charging, and particularly relates to a pulse repair charging method for inhibiting lithium precipitation of a cascade utilization battery, a battery system and a charging control device. BACKGROUND
[0002] With the large-scale application of lithium ion batteries in the field of new energy vehicles and energy storage, the number of retired batteries continues to rise globally. As the core path to solve the waste of resources and environmental risks of retired batteries, cascade utilization has shown significant cost advantages in industrial scenarios such as forklifts and low-speed logistics vehicles, with a cost of only 30% to 50% of that of a new battery. However, the initial lithium precipitation phenomenon has occurred in cascade utilization batteries during the early service process due to factors such as charging and discharging cycles and high and low temperature environments. Under the traditional constant current-constant voltage charging mode, when the state of charge of the battery reaches more than 70%, the negative active material insertion site tends to be saturated, and lithium ions are more likely to deposit on the negative electrode surface to form metallic lithium, resulting in a positive correlation between the degree of lithium precipitation and capacity attenuation. Lithium precipitation not only accelerates the decline in the cycle stability of the battery, but also may cause internal short circuits and other safety hazards, which seriously restricts the large-scale application of cascade batteries in industrial scenarios.
[0003] In the prior art, a method of pulse discharge repair after charging is completed is proposed, but this method needs to wait until the charging is completely finished and the current is reduced to zero before starting the repair. However, lithium precipitation of cascade batteries occurs in the late charging stage, at which time lithium ions have already completed deposition or even formed initial lithium dendrites, resulting in incomplete repair effect.
[0004] The prior art needs to be improved in view of the above problems. SUMMARY
[0005] The purpose of the present application is to solve the problems in the background art, and to provide a pulse repair charging method for inhibiting lithium precipitation of a cascade utilization battery, a battery system, a charging control device and a computer readable storage medium, which effectively inhibits lithium precipitation of a cascade utilization battery during charging and prolongs the service life of the battery.
[0006] The technical solution adopted by the present application is: a pulse repair charging method for inhibiting lithium precipitation of a cascade utilization battery, comprising the following steps: charging the cascade utilization battery with a set charging current variation law in the initial charging stage; charging the battery with a pulse repair intervention method when the battery parameters reach the set threshold; after the pulse repair intervention method ends, charging the battery with constant voltage until the charging current is lower than the cutoff condition, and the charging is completed; the pulse repair intervention method is to execute multiple repair pulses at intervals to discharge the battery and inhibit lithium precipitation of the battery, and a constant current is used to charge the battery between adjacent repair pulses.
[0007] Further, the charging current variation rule is: As the battery SOC increases, the charging current decreases in stages, and the charging current is constant in each stage.
[0008] Further, the pulse repair intervention mode is: When the battery parameter reaches T i , the jth repair pulse is executed to discharge the battery; After the pulse discharge is completed, the battery is charged with constant current until the battery parameter reaches the next threshold value T i+1 . Repeat the threshold value triggering-pulse discharge-constant current charging to the next threshold value process; When the nth pulse discharge is completed, the pulse repair intervention mode is completed; Wherein, T i is the ith set threshold value corresponding to the battery parameter; i is the number of set threshold values, i takes value from 1, T i+1 >T i or T i+1 <T i ; j is the number of repair pulses, j=i; n is the total number of pulse repairs, n≥2.
[0009] Further, the repair pulse is to apply a constant reverse discharge current for a set time, and the reverse discharge current and the set time of multiple repair pulses are the same or different.
[0010] Further, the range of set threshold values, reverse discharge current and set time can be adaptively dynamically adjusted according to the battery parameter through a table lookup or an algorithm model, and the battery parameter is any one or more of the battery chemical system, the current state of health of the battery, the historical cycle data, and the battery temperature.
[0011] Further, the battery parameter is the battery SOC, or the battery voltage corresponding to the battery SOC.
[0012] Further, the constant current for charging the battery between adjacent repair pulses decreases in turn.
[0013] A battery system comprising a cascade utilization battery pack and a battery management system, the battery management system being configured to be able to coordinate a charger to execute the steps of the pulse repair charging method as described above.
[0014] A charging control device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, the processor executing the computer program to implement the steps of the pulse repair charging method as described above.
[0015] A computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements the steps of the pulse repair charging method as described above.
[0016] The present application has the following beneficial effects: The present application actively suppresses the deposition of lithium ions on the negative electrode surface by introducing real-time pulse discharge intervention during charging, resulting in significant benefits, which are manifested in the following aspects: (1) Significantly prolongs the service life of the battery The present application does not passively slow down the decay, but actively repairs the lithium deposition damage that has occurred through electrochemical means, converting irreversible capacity loss into reversible loss, directly slowing down the decay rate of battery capacity from the root cause.
[0017] After such a pulse repair strategy cycle, the capacity retention rate of the battery is greatly improved compared to the battery using traditional constant current-constant voltage charging. It is expected that after the same cycle period, the remaining capacity of the battery will be increased, thereby extending its effective service life in forklift and other application scenarios by several months or even years.
[0018] (2) Effectively improves the safety and reliability of the battery Suppresses lithium dendrite growth: Regularly and actively dissolves the deposited metal lithium, which can effectively prevent the continuous growth and accumulation of lithium dendrites, and fundamentally reduces the risk of thermal runaway caused by dendrite piercing the separator.
[0019] Improves the stability of the negative electrode SEI film (solid-state electrolyte interface film): Reducing lithium deposition helps maintain the stability of the negative electrode solid-state electrolyte interface film, reduces side reactions, reduces the risk of gas production and swelling during battery cycling, and improves the safety margin of battery use.
[0020] (3) Improves the overall performance of the battery Improves charging and discharging efficiency: Repair pulses help reduce battery polarization, making lithium ion intercalation / deintercalation smoother, which can reduce the internal resistance of the battery to some extent, thereby improving its large current discharge performance, which is particularly important for forklift working conditions that require instantaneous high power output.
[0021] Ensures charging depth and available capacity: By suppressing lithium deposition at high SOC, the battery can be safely charged to a higher SOC without unnecessarily conservative upper limit charging, thereby ensuring the available energy after each charge and avoiding capacity waste due to artificially reducing the charging depth due to fear of lithium deposition.
[0022] (4) Has extremely high economic efficiency and implementation convenience "Soft" upgrade, low cost: the core of the method is the control strategy and algorithm, without major changes to the existing battery Pack or charger hardware. Can be achieved by updating the BMS firmware or charger program, upgrade cost is very low, easy to quickly promote in the existing products and markets.
[0023] Maximize the value of the use of the value: the method significantly improves the economic value of the use of the battery, which is a "waste product", prolongs the period of creating profits, and provides key technical support for the entire power battery recycling industry chain, in line with the national strategy of green and sustainable development.
[0024] (5) has intelligent and adaptive potential The parameters (SOC trigger point, pulse strength and duration) described in the present application can constitute a flexible strategy set, providing a feasible technical framework for future adaptive optimization management of "one battery one strategy" combined with battery big data and health state model, so that the charging strategy can be dynamically adjusted with the aging of the battery, and the optimal repair effect is always maintained. BRIEF DESCRIPTION OF DRAWINGS
[0025] Figure 1 Flowchart of the charging method of the present application.
[0026] Figure 2 Schematic diagram of current-SOC change during the charging process of the present application. DETAILED DESCRIPTION
[0027] In the following description, specific details are set forth such as particular system configurations, techniques, etc., in order to provide a thorough understanding of the embodiments of the application. However, persons skilled in the art will understand that the application can be practiced without these specific details. In other instances, well-known systems, devices, circuits, and methods have not been described in detail so as not to unnecessarily obscure the description of the application.
[0028] It should be understood that the reference to "one embodiment" or "some embodiments" in the description of the application means that a particular feature, structure or characteristic described in connection with the embodiment is included in one or more embodiments of the application. Therefore, the statements "in one embodiment", "in some embodiments", "in other some embodiments", "in other some embodiments" and the like appearing in the specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized. The terms "include", "contain", "have" and their variants mean "include but not limited to", unless otherwise specifically emphasized.
[0029] As Figure 1、 Figure 2 As shown in the specification, the application proposes a pulse repair charging method for inhibiting lithium precipitation of cascade utilization battery, comprising the following steps: In the initial charging stage, the cascade utilization battery is charged with a set charging current variation rule; When the battery parameters reach the set threshold, the battery is charged by pulse repair intervention method; After the pulse repair intervention method ends, the battery is charged at constant voltage until the charging current is lower than the cutoff condition, and the charging ends; The pulse repair intervention method is to execute multiple repair pulses at intervals to make the battery discharge and inhibit the lithium precipitation phenomenon of the battery, and a constant current is used to charge the battery between adjacent repair pulses.
[0030] The charging method of the application is a charging strategy designed for lithium ion batteries that have been retired and used in cascade. The core is to introduce a specific pulse discharge operation during charging, actively intervene and dissolve the formed or about to form lithium dendrites, thereby inhibiting the lithium precipitation phenomenon of the battery negative electrode, prolonging the service life and safety of the battery.
[0031] For ease of understanding, some key terms in the present embodiment are explained as follows: Cascade utilization battery: refers to a lithium ion battery pack or battery module that has reached the retirement standard in its original application scenario (such as electric vehicles), but still has certain capacity and life after inspection, and can be applied to other lower requirement scenarios (such as forklifts, energy storage, etc.).
[0032] Lithium precipitation: refers to the phenomenon that lithium ions cannot be timely embedded in the interlayer of the negative electrode graphite during the charging process of lithium ion batteries, especially at low temperature, high rate or high state of charge, and are reduced and deposited on the negative electrode surface to form metallic lithium. Lithium precipitation irreversibly consumes active lithium, leading to battery capacity attenuation and potential safety hazards such as internal short circuit, which is a key factor affecting battery life and safety.
[0033] Initial charging stage: refers to the initial part of the battery charging process, usually from the start of charging until certain key parameters of the battery reach the preset specific state. In this stage, the charging strategy is usually aimed at quickly and stably increasing the battery power to prepare for subsequent fine charging and repair intervention.
[0034] Battery parameters: refer to physical or chemical quantities used to characterize the current state of the battery, such as state of charge (SOC), battery voltage, battery temperature, internal resistance, capacity decay rate, etc. These parameters are important basis for judging battery health and charging stage.
[0035] Threshold: refers to the pre-set critical value of battery parameters. When the battery parameters reach or exceed these thresholds, specific charging behaviors or interventions will be triggered, such as initiating pulse repair interventions.
[0036] Pulse repair intervention mode: refers to a repair operation that is periodically or conditionally inserted during charging. This mode aims to dissolve the deposited metal lithium on the negative electrode surface or inhibit the growth of lithium dendrites by performing short discharging pulses during charging gaps, thereby repairing battery performance.
[0037] Repair pulse: refers to a specific discharging operation in the pulse repair intervention mode. It usually manifests as a short-term interruption of charging during the charging process, and makes the battery discharge for a short time to achieve the purpose of dissolving lithium.
[0038] Constant current: refers to the charging current remaining a fixed value during a specific charging phase or the gap of pulse repair intervention. Using constant current charging helps to stabilize the battery state and provides a stable basis for the next repair pulse or charging phase.
[0039] Constant voltage charging: refers to the charging process in the later stage, when the battery voltage reaches the pre-set maximum charging voltage, the charger will keep the output voltage constant, while the charging current will gradually decrease with the increase of battery capacity. This is a common stage of lithium-ion battery charging, aiming to fully charge the battery and ensure safety.
[0040] Cut-off condition: refers to the criterion for ending the charging process, usually when the charging current drops to a certain pre-set minimum value in the constant voltage charging phase, the charging process is terminated.
[0041] The method proposed in this application realizes the active inhibition of lithium precipitation by timely introducing pulse repair interventions based on battery parameters during the charging process of the ladder utilization battery. The method uses a set current law in the initial charging stage, and discharges the battery by performing multiple repair pulses at intervals during the high-risk period of lithium precipitation, while charging with constant current in the pulse gap, effectively dissolving the potential metal lithium and avoiding the risk of lithium precipitation from the source. Therefore, this method can significantly improve the cycle stability and service life of the ladder utilization battery, while avoiding the problems of repair lag, efficiency damage, high hardware dependency and narrow scene adaptability of traditional repair schemes, meeting the needs of industrial scenarios for efficient and long-life charging.
[0042] In one embodiment, the application further proposes that in the initial charging stage, the charging current variation law is that as the battery SOC increases, the charging current decreases in stages, and the charging current is constant in each stage.
[0043] Specifically, the charging current variation rule refers to the preset or dynamically adjusted rule that governs the change of charging current with time or battery state (such as SOC, voltage, temperature, etc.) during battery charging. Its purpose is to optimize the charging process to balance charging speed, battery life, and safety. This rule can be implemented through a pre-programmed charging curve, a dynamic adjustment algorithm based on real-time battery parameters, or by consulting a preset current-SOC correspondence table.
[0044] Maintaining a constant charging current within each preset SOC stage helps simplify the charging control strategy and improves the stability of the charging process. Constant current charging can ensure charging efficiency to a certain extent, especially in the lower SOC stage, where a higher constant current can be used to quickly replenish the charge. At the same time, this phased constant current charging mode also facilitates accurate charge amount calculation and status monitoring by the charging management system. The charger uses closed-loop control to monitor the charging current in real time and adjust it according to the preset constant current target value to ensure that the current remains stable within the current SOC stage. For example, in the 0-30% SOC stage, a 0.5C constant current charging is set; in the 30-60% SOC stage, a 0.3C constant current charging is set, and so on.
[0045] Through the above technical solution, in the initial stage of charging, when the battery's SOC is low, a relatively high constant current can be used for fast charging to ensure charging efficiency. Conversely, when the battery's SOC is high, the constant current is reduced to provide more time for lithium ion insertion, significantly reducing the risk of lithium plating in the high SOC region. This staged, constant-current charging strategy not only simplifies the complexity of charging control and improves the stability of the charging process, but also allows for optimized adjustments based on the actual state of the battery. This effectively suppresses lithium plating in secondary batteries without significantly sacrificing charging efficiency, thus extending battery life.
[0046] In one embodiment, this application further proposes a pulse repair intervention method as follows: When the battery parameters reach T i At that time, the j-th repair pulse is executed to discharge the battery; After the pulse discharge ends, the battery is charged with a constant current until the battery parameters reach the next threshold T. i+1 ; Repeat the above process of threshold triggering, pulse discharge, and constant current charging to the next threshold. The pulse repair intervention ends when the nth pulse discharge ends. Among them, T i This is the preset threshold value corresponding to the battery parameters; i is the threshold number, starting from 1, T i+1 >T i or Ti+1 <T i j represents the number of times the repair pulse is executed, j=i; n represents the preset total number of pulse repairs, n≥2.
[0047] Specifically, when the battery parameters reach T i At that time, the j-th repair pulse is executed to discharge the battery. The battery parameters here can be battery SOC, battery voltage, battery internal resistance, or battery temperature, etc. When any one or more of these parameters reaches a preset threshold T... i At this time, the charging system will trigger a repair pulse. For example, the battery management system (BMS) can monitor the battery voltage or SOC in real time, and once it detects that it has reached a preset T... i Upon receiving the value, the system immediately sends a command to the charging controller to initiate a pulse discharge operation. Alternatively, the charging controller can predict the battery parameters to reach T based on the battery's charging history data and current state using an internal algorithm. i This mechanism, based on dynamic triggering of battery parameters, ensures that the repair pulse intervenes promptly when the risk of lithium plating increases or when initial signs of lithium plating appear, avoiding blind or delayed repair.
[0048] After the pulse discharge ends, the battery is charged with a constant current until the battery parameters reach the next threshold T. i+1 After completing a repair pulse discharge, the system switches back to constant current charging mode to continue the charging process and prepare for the next repair intervention. For example, the charging controller can charge the battery with a stable current value according to a preset charging strategy, while continuously monitoring battery parameters until it reaches the next preset threshold T. i+1 Alternatively, the charging device can dynamically adjust the constant current based on the battery's real-time status and charging stage to optimize charging efficiency and lithium plating suppression, ensuring that the charging process reaches T... i+1 Previously, the battery could accept charging smoothly, providing suitable conditions for subsequent pulse repair. This constant current charging avoids the risk of lithium plating that may arise from high-rate charging immediately after pulse discharge, while also providing a buffer for the next precise repair timing.
[0049] The entire pulse repair intervention is not completed in one go, but rather through multiple loops executing a sequence of "parameter monitoring - pulse discharge - constant current charging". For example, the charging control system can incorporate a state machine or loop control logic, based on a preset total number of repairs n and a series of thresholds T. iThe system automatically schedules the switching of charging modes to ensure that lithium plating can be suppressed in stages and multiple times throughout the charging process. This repetitive execution mechanism allows the repair intervention to cover different stages of battery charging, especially the later stages when lithium plating is most prevalent, thereby achieving continuous and comprehensive suppression of lithium plating and avoiding the limitations that may exist in a single repair.
[0050] To avoid excessive intervention and unnecessary extension of charging time, the pulse repair intervention method has a clearly defined termination condition. For example, a counter can be set inside the charging controller to record the number of pulse discharges executed. When the counter reaches the preset total number of pulse repairs, n, the system stops triggering new pulse discharges and exits the pulse repair intervention mode, transitioning to the next stage of the charging process, such as constant voltage charging. This clear termination condition ensures the effectiveness and efficiency of the repair process and avoids waste of resources.
[0051] It should be noted that T i As a preset threshold, it can be finely set according to factors such as the battery's chemical system, health status, and temperature. For example, for lithium iron phosphate batteries, T i It can be set to a specific voltage value or SOC percentage. `i` serves as the threshold number, starting from 1, ensuring the ordered nature of the threshold sequence. Setting `Ti+1>Ti` or `Ti+1<Ti` allows the threshold sequence to be flexibly adjusted according to the changing trends of battery parameters. For example, during charging, voltage or SOC usually increases, but certain specific parameters may decrease. `j` equals `i`, ensuring that each trigger corresponds to one repair pulse execution, maintaining precise intervention matching. `n≥2` guarantees at least two repair interventions to address the cumulative effect of lithium plating, while avoiding the incompleteness that a single repair might cause. The specific value of `n` can be optimized based on factors such as battery health, charging rate, and expected lifespan. For example, for batteries in good health for secondary use, two pulses can be executed only at 80% and 95% SOC to optimize charging efficiency; while for batteries with more severe aging, four pulses can be executed at four SOC points: 60%, 70%, 80%, and 90%, to provide more intensive repair protection.
[0052] Through the above technical solution, this application achieves precise and phased suppression of lithium plating during the charging process. This refined pulse repair intervention strategy enables the secondary battery to be more effectively protected during the charging process, significantly suppressing the occurrence and development of lithium plating, thereby extending the battery's service life. At the same time, it avoids problems such as delayed repair timing and impaired charging efficiency in traditional repair methods, improving the overall efficiency and safety of the charging process.
[0053] In one embodiment, this application further proposes that the repair pulse applies a constant reverse discharge current for a set time, and the reverse discharge current and set time of multiple repair pulses are the same or different.
[0054] Specifically, the repair pulse is achieved by applying a constant reverse discharge current. This constant reverse discharge current serves to stably and effectively dissolve the lithium deposits already formed on the surface of the battery's negative electrode, thereby suppressing lithium plating. In practice, the constant reverse discharge current can be applied in various ways. For example, the power conversion module inside the charging device can connect the battery to a controllable discharge circuit and precisely control the current output of that circuit to maintain it at a preset constant value, such as using a constant current source circuit to provide a stable reverse discharge current. Alternatively, the charging device can monitor the battery's voltage and current in real time and, in conjunction with a PID (proportional-integral-derivative) controller or other closed-loop control algorithms, dynamically adjust the load or conduction angle of the discharge circuit or power devices to ensure that the reverse current flowing through the battery is always maintained at the target constant value.
[0055] Simultaneously, the repair pulse is also set for a set duration. This set duration aims to ensure that the discharge process has sufficient duration to affect lithium plating, while avoiding excessively long discharges that could impact the overall charging progress. The method for achieving this set duration can include: the charging control unit incorporating a timer module that starts timing when the reverse discharge current begins to be applied and automatically cuts off the discharge circuit and stops reverse discharge after the preset set time is reached; or, the charging control system implementing time control through software programming, recording the start timestamp during the execution of the repair pulse, and continuously monitoring the current time. Once the difference between the current time and the start timestamp reaches or exceeds the preset set time, a command to stop discharging is triggered.
[0056] Furthermore, this application proposes that the reverse discharge current and set time of multiple repair pulses can be the same or different. This design makes the repair strategy flexible and adaptive, capable of dynamically adjusting according to the actual state of the battery. For example, the charging control system can preset multiple sets of reverse discharge current and set time parameters, and select one set of parameters to apply each time a repair pulse is executed, based on the current state of the battery (such as SOC, temperature, health status, etc.) or the preset repair strategy. When the risk of lithium plating is high, a larger reverse discharge current or a longer set time can be used; while when the risk is low, milder parameters can be used.
[0057] This application allows for flexible and adaptive repair strategies by enabling the reverse discharge current and set time of multiple repair pulses to be the same or different. This dynamic adjustment capability allows the repair process to better adapt to the complex characteristics and inconsistencies of second-generation batteries, thereby more thoroughly suppressing lithium plating and extending battery life without significantly reducing overall charging efficiency. Compared to repair methods with fixed parameters, this scheme can more effectively balance lithium plating suppression and charging efficiency, improving the practicality and effectiveness of the entire pulse repair charging method.
[0058] In one embodiment, this application further proposes that the range of setting threshold, reverse discharge current, and setting time can be adaptively and dynamically adjusted according to battery parameters through table lookup or algorithm model. The battery parameters are any one or more of the battery's chemical system, current battery health status, historical cycle data, and battery temperature.
[0059] The adaptive dynamic adjustment mechanism aims to flexibly optimize the parameters of the repair pulse based on the real-time or historical state of the battery, ensuring maximum repair effectiveness and maintained charging efficiency. One implementation method is through table lookup. The system pre-stores one or more parameter lookup tables, which preset corresponding threshold values, reverse discharge currents, and set times based on different battery parameters (such as chemical system, current battery health, battery temperature, etc.). During charging, the system acquires battery parameters in real time and searches the tables for the most matching combination of repair parameters. Another implementation method is through algorithmic models. The system can employ machine learning models (such as decision trees, neural networks), regression analysis models, or rule-based expert systems. These models, trained and learned from large amounts of battery data (including lithium plating and repair effects under different battery parameters), can calculate or predict the optimal threshold values, reverse discharge currents, and set times in real time based on the current battery parameters.
[0060] The battery parameters are the basis for adaptive dynamic adjustments. They reflect the battery's intrinsic characteristics and external environmental conditions, significantly impacting lithium plating behavior and repair effectiveness. The battery's chemical system refers to the types of positive and negative electrode materials, such as lithium iron phosphate and ternary lithium. Different chemical systems have different electrochemical characteristics and lithium plating tendencies, thus requiring different repair parameters. These parameters are typically determined during battery manufacturing and can be obtained through the Battery Management System (BMS) or battery specification information. The battery's current state of health (SOH) reflects its aging degree and performance degradation, such as internal resistance, usable capacity, and power performance. SOH can be estimated in real-time by the BMS (e.g., through trends in ohmic internal resistance and polarization internal resistance) or obtained through periodic capacity testing. Batteries with poorer SOH may have a higher risk of lithium plating and require more aggressive repair strategies. Historical cycle data includes the battery's cumulative charge-discharge cycle count, cumulative charge-discharge capacity, average operating temperature, and high / low temperature cycle count. This data reflects the battery's long-term service life and aging path, providing crucial information for predicting future lithium plating risks and optimizing repair parameters. This data is typically recorded and stored by the BMS. Battery temperature refers to the ambient or internal temperature of the battery during operation. Temperature significantly affects the migration rate of lithium ions in the electrolyte, the kinetics of the negative electrode insertion reaction, and the activation energy of the lithium plating reaction. For example, lithium ions are more likely to deposit and form metallic lithium at low temperatures. Battery temperature is typically monitored in real time using a built-in temperature sensor.
[0061] Through the above technical solution, this application can adaptively and dynamically adjust the key parameters in the pulse repair intervention method according to the actual working conditions and aging characteristics of the battery, thereby significantly improving the accuracy and effectiveness of suppressing lithium plating in secondary batteries.
[0062] In one embodiment, this application further proposes that the reverse discharge current and the set time be dynamically adjusted within the following ranges: the adjustment range of the reverse discharge current is 0.8C to 1.2C discharge rate; the adjustment range of the set time is 8s to 15s.
[0063] In pulse repair intervention, the reverse discharge current refers to the current used to discharge the battery. Its magnitude is typically expressed as the battery's C-rate, which is a multiple of the battery's rated capacity. For example, 1C discharge refers to discharging the battery at a current multiple that would empty its rated capacity in one hour. For a 100Ah battery, the 1C discharge current is 100A. This adjustment range is designed to ensure that the reverse discharge current effectively dissolves existing lithium deposits without causing excessive stress or damage to the battery. Specifically, the lower limit of 0.8C ensures that the discharge current has sufficient intensity to effectively trigger the electrochemical dissolution reaction of lithium deposits. For instance, when battery parameters (such as battery SOC and battery temperature) indicate a high risk of lithium plating, the system can adjust the reverse discharge current to 0.8C or slightly higher based on the algorithm model or lookup table results to provide sufficient energy density to promote lithium re-intercalation. The 1.2C upper limit restricts the maximum discharge current to prevent excessive current from causing a sharp rise in battery internal temperature, damage to electrode material structure, or accelerated battery aging. For example, even if battery parameters require intensive repair, the system will limit the reverse discharge current to within 1.2C to ensure the long-term health and safety of the battery.
[0064] The set time refers to the duration of each repair pulse (reverse discharge) in the pulse repair intervention method. Setting this adjustment range aims to ensure that the duration of each repair pulse guarantees the repair effect without significantly prolonging the overall charging time and affecting charging efficiency. Specifically, the lower limit of 8 seconds ensures that each pulse discharge has a sufficient time window, allowing lithium deposits ample opportunity for electrochemical dissolution. For example, when battery parameters indicate a mild degree of lithium plating or a less urgent repair need, the system can choose to adjust the set time to 8 seconds or slightly longer to achieve a gentle yet effective repair. The upper limit of 15 seconds restricts the maximum duration of each pulse discharge, preventing a significant extension of the charging cycle due to excessively long single discharge times, which could impact the stringent charging efficiency requirements of industrial applications. For example, even in cases requiring longer repair times, the system will limit the set time to within 15 seconds to balance repair effectiveness and charging efficiency.
[0065] Through the above technical solution, this application ensures that these parameters remain within the optimized range during adaptive adjustment by specifically limiting the dynamic adjustment range of reverse discharge current and set time. This effectively suppresses lithium plating while avoiding battery damage or charging efficiency loss. These range constraints work together to ensure that adaptive adjustment operates within a safe and effective range even when battery parameters change. This effectively suppresses lithium plating in secondary batteries without significantly reducing charging efficiency, extending battery life. It is particularly suitable for industrial applications with stringent charging efficiency requirements.
[0066] In one embodiment, this application further proposes that the aforementioned battery parameters refer to physical or chemical quantities used to characterize the current state of the battery, such as any one of the following: state of charge (SOC), battery voltage, battery temperature, internal resistance, capacity decay rate, etc. These parameters are important bases for judging the battery's health status and charging stage.
[0067] Specifically, the battery SOC refers to the percentage of the battery's current remaining charge relative to its total capacity, and is a key indicator for measuring the battery's state of charge. By directly monitoring the battery SOC, it is possible to accurately identify the stage where the battery is in a high state of charge (e.g., SOC ≥ 70%), where the negative electrode lithium-ion insertion sites are saturated and the risk of lithium plating is increased, thereby avoiding delays or erroneous triggering that may be caused by using indirect parameters. At this time, the corresponding multiple SOC thresholds can be adaptively adjusted as needed. For example, when executing three repair pulses, the adjustment ranges of the three SOC thresholds can be: S1 (60%~75%), S2 (75%~85%), and S3 (85%~95%), preferably 70%, 80%, and 90%.
[0068] Battery voltage, corresponding to battery SOC, refers to the specific relationship between the voltage across the battery terminals and the SOC under a particular operating state. In practical applications, battery voltage measurement is relatively simple and inexpensive, thus serving as an indirect but effective substitute for SOC. By pre-calibrating the battery's open-circuit voltage-SOC curve, a specific SOC value can be converted into a corresponding voltage threshold. This allows for real-time monitoring of the battery terminal voltage during charging, and judgments can be made based on the preset voltage threshold, which corresponds to the SOC range with a high risk of lithium plating. For example, based on the battery's OCV-SOC curve, the open-circuit voltage value corresponding to a 70% SOC can be determined, and this voltage value can be used as the threshold for triggering pulse repair intervention.
[0069] Through the above technical solution, this application clarifies that the battery parameter used to trigger pulse repair intervention is the battery SOC or the battery voltage corresponding to the battery SOC, thereby ensuring the accuracy and reliability of the threshold setting. Directly using the battery SOC as the monitoring indicator allows the threshold setting to be directly based on the battery's state of charge, which helps to accurately identify the high SOC stage prone to lithium plating and avoids delays or erroneous triggering that may result from using indirect parameters. Alternatively, using the battery voltage corresponding to the battery SOC provides operational convenience in practical applications, as voltage measurement is easier to implement and less costly. Furthermore, by ensuring the consistency between the voltage threshold and the SOC threshold, the continuity of the triggering logic is maintained, preventing malfunctions caused by parameter mismatch.
[0070] In one embodiment, this application further proposes that the constant current for charging the battery decreases sequentially between adjacent repair pulses.
[0071] This technical feature refers to the gradual decrease in the constant current applied during the constant current charging process before the next repair pulse, after each repair pulse ends and before the next repair pulse begins in the pulse repair intervention method. This "sequential decrease" strategy aims to adapt to the gradual increase in the battery's SOC during charging, thereby optimizing the charging process. One implementation method is to preset a series of decreasing constant current values. For example, multiple charging current values can be pre-determined based on the expected total number of pulse repairs, ensuring that each subsequent current value is less than the previous current value, and these current values are applied sequentially during the charging phase between each adjacent repair pulse. These current values can be calibrated based on factors such as battery type, capacity, and aging degree. Another implementation method is to dynamically adjust the constant current based on the real-time state of the battery. For example, after each repair pulse ends, the system can detect parameters such as the battery's current SOC, voltage, or temperature, and calculate the constant current value to be applied in the next charging phase according to a preset algorithm or lookup table method. This algorithm ensures that the calculated current value is less than the current value of the previous charging phase, thus achieving a sequential decrease in current.
[0072] Through the above technical solution, the constant current for charging the battery between adjacent repair pulses decreases sequentially. This application can effectively address the risk of lithium plating caused by the gradual increase of SOC during pulse repair charging of second-hand batteries. This refined current control strategy enables second-hand batteries to be charged more stably and safely during the repair process, extending their service life and meeting the charging efficiency requirements of industrial scenarios.
[0073] A preferred embodiment of the core method of this application includes the following steps: Step 1: Charging initialization and basic constant current charging.
[0074] Connect the charging device to the secondary battery pack. Initiate the charging process, initially charging the battery with a safe and efficient constant current I_charge (e.g., 0.3C to 0.5C rate). The battery management system monitors and calculates the battery's real-time state of charge (SOC). As the SOC increases, the charging current decreases in stages, remaining constant at each stage.
[0075] Step 2: Initial pulse repair intervention (at the first SOC threshold point).
[0076] When the BMS detects that the battery's SOC has reached a preset first threshold S1 (preferably 70%), it immediately sends a command to the charger to stop the constant current charging process. Subsequently, the charger executes the first repair pulse: applying a constant reverse discharge current I_pulse (ranging from 0.5C to 1.5C, preferably 1C) and maintaining it for a short duration T_pulse (ranging from 5 seconds to 30 seconds, preferably 10 seconds).
[0077] Step 3: Resume charging and secondary pulse repair intervention (at the second SOC threshold point).
[0078] After the first repair pulse ends, the charger immediately charges the battery at the set constant current. When the battery SOC continues to rise to the second threshold S2 (preferably 80%), charging is stopped again, and a second repair pulse with the same parameters as in step two is executed (i.e., 1C discharge for 10 seconds).
[0079] Step 4: Last pulse repair intervention and charging termination (at the third SOC threshold point).
[0080] After the second repair pulse ends, constant current charging resumes. When the battery SOC reaches the third threshold S3 (preferably 90%), a third repair pulse is executed, with parameters identical to the previous two. The completion of the third repair pulse marks the end of the core "repair phase" of this invention. Afterward, the charging program can transition to a conventional constant voltage charging phase, stabilizing the battery voltage at its upper limit and waiting for the charging current to naturally decay to the cutoff condition (e.g., 0.05C), ultimately completing the entire charging process.
[0081] This application also provides a battery system including a secondary battery pack and a battery management system, wherein the battery management system is configured to coordinate a charger to perform the steps of the pulse repair charging method as described above.
[0082] This application also provides a charging control device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the pulse repair charging method as described above.
[0083] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the pulse repair charging method described above.
[0084] In applications, the processor can be a Central Processing Unit (CPU), but it can also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.
[0085] In applications, memory can be an internal storage unit of an electronic device in some embodiments, such as a hard drive or RAM. In other embodiments, memory can be an external storage device of the electronic device, such as a plug-in hard drive, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card. Furthermore, memory can include both internal and external storage units of the electronic device. Memory is used to store operating systems, applications, bootloaders, data, and other programs, such as program code for computer programs. Memory can also be used to temporarily store data that has been output or will be output.
[0086] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments of this application can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. A computer-readable medium can include at least: any entity or device capable of carrying computer program code to a device / electronic device, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium. Examples include USB flash drives, portable hard drives, magnetic disks, or optical disks. In some jurisdictions, according to legislation and patent practice, computer-readable media cannot be electrical carrier signals or telecommunication signals.
[0087] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.
[0088] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.
[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit its scope of protection. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading the present invention, they can still make various changes, modifications, or equivalent substitutions to the specific implementation of the invention, but all such changes, modifications, or equivalent substitutions are within the scope of protection of the pending claims. Content not described in detail in this specification belongs to the prior art known to those skilled in the art.
Claims
1. A pulse repair charging method for suppressing lithium plating in secondary batteries, characterized in that: In the initial stage of charging, the batteries to be reused are charged according to the set charging current variation pattern. When the battery parameters reach the set threshold, the battery is charged using a pulse repair intervention method. After the pulse repair intervention ends, the battery is charged under constant voltage until the charging is complete; The pulse repair intervention method involves executing multiple repair pulses at intervals to discharge the battery and suppress lithium plating, while a constant current is used to charge the battery between adjacent repair pulses.
2. The pulse repair charging method for suppressing lithium plating in secondary-use batteries according to claim 1, characterized in that: The charging current variation pattern is as follows: As the battery's state of charge (SOC) increases, the charging current decreases in stages, with the charging current remaining constant in each stage.
3. The pulse repair charging method for suppressing lithium plating in secondary-use batteries according to claim 1, characterized in that: The pulse repair intervention method is as follows: When the battery parameters reach T i At that time, the j-th repair pulse is executed to discharge the battery; After the pulse discharge ends, the battery is charged with a constant current until the battery parameters reach the next threshold T. i+1 ; Repeat the above process of threshold triggering, pulse discharge, and constant current charging to the next threshold. The pulse repair intervention ends when the nth pulse discharge ends. Among them, T i This is the preset threshold value corresponding to the battery parameters; i is the number of the threshold value, starting from 1, T i+1 >T i or T i+1 <T i j represents the number of times the repair pulse is executed, j=i; n represents the preset total number of pulse repairs, n≥2.
4. The pulse repair charging method for suppressing lithium plating in secondary-use batteries according to claim 3, characterized in that: The repair pulse is the application of a constant reverse discharge current for a set time. The reverse discharge current and the set time of multiple repair pulses may be the same or different.
5. The pulse repair charging method for suppressing lithium plating in secondary-use batteries according to claim 4, characterized in that: The ranges for the set threshold, reverse discharge current, and set time can be adaptively and dynamically adjusted based on battery parameters through table lookup or algorithm model. The battery parameters are any one or more of the following: battery chemical system, current battery health status, historical cycle data, and battery temperature.
6. The pulse repair charging method for suppressing lithium plating in secondary-use batteries according to claim 1, characterized in that: The battery parameter is the battery SOC, or the battery voltage corresponding to the battery SOC.
7. The pulse repair charging method for suppressing lithium plating in secondary-use batteries according to claim 1, characterized in that: The constant current for charging the battery decreases sequentially between adjacent repair pulses.
8. A battery system comprising a secondary battery pack and a battery management system, characterized in that: The battery management system is configured to coordinate the charger to perform the steps of the pulse repair charging method as described in any one of claims 1 to 7.
9. A charging control device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, it implements the steps of the pulse repair charging method as described in any one of claims 1 to 7.
10. A computer-readable storage medium storing a computer program thereon, characterized in that: When the computer program is executed by the processor, it implements the steps of the pulse repair charging method as described in any one of claims 1 to 7.