Battery cell charging method, control processing unit and energy storage system

Abstract

The application discloses a battery cell charging method, a control processing unit and an energy storage system. The battery cell charging method comprises the following steps: acquiring characteristic parameters of a charging end of N continuous historical charges immediately before a current charging, the charging end being a time period from meeting condition one and / or condition two to the end of charging, the condition one being that a state of charge value of the battery cell is greater than a state of charge inflection point threshold, and the condition two being that a voltage of the battery cell is greater than a constant current charging upper inflection point critical potential; determining an abnormal risk level according to an average value of peak rates of the N historical charges and an abnormal alarm number; adjusting a charging current upper limit value and a constant voltage target voltage according to the overvoltage risk level, and adjusting the charging current upper limit value and a maximum charging power according to an overtemperature risk level; and performing the current charging. In the foregoing manner, active prediction and pre-protection of the charging risk can be realized, so as to overcome the defects that related technologies can only be remedied afterwards and cannot identify implicit hidden dangers.

Description

Technical Field

[0001] This application relates to the field of charging technology, and in particular to a battery cell charging method, a control processing unit, and an energy storage system. Background Technology

[0002] In energy storage systems composed of battery cells, safe control during the charging process is crucial. Traditional safety control methods mainly rely on real-time threshold monitoring: real-time acquisition of status parameters such as cell voltage, temperature, and charge level; when the cell voltage, temperature, or charge level reaches a preset alarm threshold, the system immediately stops charging, issues an alarm, or takes protective action.

[0003] However, existing control schemes have the following drawbacks: relying solely on threshold-triggered protection lacks the ability to proactively predict risks, making it a passive "remedial" protection mode. This not only leads to frequent alarms affecting user experience but also causes potential hazards to accumulate due to delayed responses, potentially inducing safety incidents such as abnormal thermal activity in the power cells. Summary of the Invention

[0004] This application provides a battery cell charging method, a control processing unit, and an energy storage system, which can achieve proactive prediction and prevention of charging risks, overcoming the shortcomings of related technologies that can only provide post-event remedies and cannot identify hidden dangers.

[0005] In a first aspect, embodiments of this application provide a battery cell charging method, comprising: acquiring characteristic parameters of the charging end of N consecutive historical charges that are sequentially adjacent to the current charge, wherein the characteristic parameters include the peak voltage rise rate and peak temperature rise rate of each charge, and the number of overvoltage alarms and overtemperature alarms of the N historical charges, the charging end being the time period from the satisfaction of condition one and / or condition two to the end of charging, condition one being that the state of charge value of the battery cell is greater than the state of charge inflection point threshold, condition two being that the voltage of the battery cell is greater than the inflection point critical potential of constant current charging, and N being a positive integer. The system counts the peak rates of N historical charging cycles and determines the abnormal risk level based on the average of the peak rates and the number of abnormal alarms. The peak rate is the rate of increase of peak voltage or peak temperature, the number of abnormal alarms is the number of overvoltage alarms or overtemperature alarms, and the abnormal risk level is the overvoltage risk level or overtemperature risk level. Based on the overvoltage risk level, the system adjusts the upper limit of the charging current and the constant voltage target voltage, and based on the overtemperature risk level, it adjusts the upper limit of the charging current and the maximum charging power. Finally, the system executes the current charging cycle based on the adjusted upper limit of the charging current, the constant voltage target voltage, and the maximum charging power.

[0006] In one or more embodiments, after performing the step of performing the current charge based on the adjusted upper limit of charging current, the constant voltage target voltage, and the maximum charging power, the method further includes: determining characteristic parameters of the charging end of the current charge.

[0007] In one or more embodiments, the step of determining the characteristic parameters of the charging end of the current charging cycle includes: acquiring the charging condition parameters of the battery cell, wherein the charging condition parameters include voltage, temperature, and charge; determining the peak rate based on the charging condition parameters when it is determined that condition one and / or condition two are met; and determining the number of abnormal alarms based on whether the charging has ended normally, wherein no overvoltage alarm or overtemperature alarm occurs during charging, which corresponds to normal charging end, and an overvoltage alarm or overtemperature alarm occurs during charging, which corresponds to charging not ending normally.

[0008] In one or more embodiments, the step of determining the peak rate based on charging condition parameters includes: determining the instantaneous rate corresponding to the Kth moment based on the ratio of the Kth difference to the Kth time interval during the charging process, thereby determining M instantaneous rates during the charging process, wherein the Kth difference is the difference between the voltage at the Kth moment and the voltage at the (K-1)th moment or the difference between the temperature at the Kth moment and the temperature at the (K-1)th moment, the Kth time interval is the time interval between the Kth moment and the (K-1)th moment, and the instantaneous rate is the instantaneous voltage rise rate or the instantaneous temperature rise rate, K and M are both integers, and 1≤K≤M; performing a moving average operation on the M instantaneous rates to obtain J average rates, wherein J is an integer, and 0<J<M; and taking the maximum value among the J average rates as the peak rate.

[0009] In one or more embodiments, the step of determining the number of abnormal alarms based on whether charging has ended normally includes: when charging ends normally, the number of abnormal alarms remains unchanged; when charging ends abnormally and the peak rate is greater than a first rate threshold, the number of abnormal alarms is incremented by one, wherein the first rate threshold is less than the abnormal alarm threshold, and the abnormal alarm threshold is an overvoltage alarm threshold or an overtemperature alarm threshold; when charging ends abnormally and the peak rate is less than or equal to the first rate threshold, the characteristic parameters of the charging end of that charging session are determined to be invalid parameters.

[0010] In one or more embodiments, the step of determining the abnormal risk level based on the average peak rate of N historical charging cycles and the number of abnormal alarms includes: determining the abnormal risk level as high risk when the average rate is greater than an abnormal alarm threshold, or when the number of abnormal alarms is greater than a first threshold; determining the abnormal risk level as medium risk when the average rate is greater than a first rate threshold and less than or equal to the abnormal alarm threshold, and when the number of abnormal alarms is less than or equal to the first threshold; and determining the abnormal risk level as low risk when the average rate is less than or equal to the first rate threshold.

[0011] In one or more embodiments, the step of adjusting the upper limit of the charging current and the constant voltage target voltage according to the overvoltage risk level includes: when the overvoltage risk level is high, reducing the upper limit of the charging current by a first percentage and reducing the constant voltage target voltage; when the overvoltage risk level is medium, reducing the upper limit of the charging current by a second percentage and keeping the constant voltage target voltage unchanged, wherein the second percentage is less than the first percentage; and when the overvoltage risk level is low, keeping the upper limit of the charging current and the constant voltage target voltage unchanged.

[0012] In one or more embodiments, the step of adjusting the upper limit of charging current and the maximum charging power according to the over-temperature risk level includes: when the over-temperature risk level is high, reducing the upper limit of charging current by a third percentage and limiting the maximum charging power to less than a first power threshold; when the over-temperature risk level is medium, reducing the upper limit of charging current by a fourth percentage and keeping the maximum charging power unchanged, wherein the fourth percentage is less than the third percentage; and when the over-temperature risk level is low, keeping the upper limit of charging current and the maximum charging power unchanged.

[0013] Secondly, embodiments of this application provide a control processing unit, including: at least one processor and a memory; the memory is coupled to the processor and is used to store instructions or programs, which, when executed by at least one processor, cause at least one processor to execute the battery cell charging method of the first aspect.

[0014] Thirdly, embodiments of this application provide an energy storage system, including at least one battery cell and a control processing unit as described in the second aspect. The control processing unit is electrically connected to the battery cell to control the charging process of the battery cell.

[0015] The beneficial effects of this application are as follows: The battery cell charging method of this application first obtains the characteristic parameters of the charging end of N consecutive historical charges that are immediately adjacent to the current charging in terms of timing. Then, based on the average peak rate of the N historical charges and the number of abnormal alarms, the abnormal risk level is determined. Subsequently, the upper limit of the charging current and the constant voltage target voltage are adjusted according to the overvoltage risk level, and the upper limit of the charging current and the maximum charging power are adjusted according to the overtemperature risk level. Finally, the current charging is executed based on the adjusted upper limit of the charging current, the constant voltage target voltage, and the maximum charging power. In this way, proactive prediction and prevention of charging risks can be achieved, overcoming the shortcomings of related technologies that can only remedy problems after the fact and cannot identify hidden dangers. At the same time, it can adaptively match the charging control parameters according to the differences in the historical charging characteristics of the battery cell, adapt to the individual differences and aging states of different battery cells, avoid aging battery cells being in critical operating conditions for a long time, delay battery cell degradation, and improve charging safety. In addition, a historical charging data memory and analysis mechanism is introduced, and the charging control strategy is continuously iterated and optimized based on multi-cycle historical data, so that the control logic can dynamically adapt to the performance evolution of the battery cell throughout its entire life cycle, significantly improving the accuracy of charging risk identification and control reliability. Attached Figure Description

[0016] 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.

[0017] Figure 1 This is the flow chart of the battery cell charging method provided in the embodiments of this application. Figure 1 ; Figure 2 This is the flow chart of the battery cell charging method provided in the embodiments of this application. Figure 2 ; Figure 3 This is the flow chart of the battery cell charging method provided in the embodiments of this application. Figure 3 ; Figure 4 This is the flow chart of the battery cell charging method provided in the embodiments of this application. Figure 4 ; Figure 5 This is the flow chart of the battery cell charging method provided in the embodiments of this application. Figure 5 ; Figure 6 This is the flow chart of the battery cell charging method provided in the embodiments of this application. Figure 6 ; Figure 7 This is the flow chart of the battery cell charging method provided in the embodiments of this application. Figure 7 ; Figure 8 This is the flow chart of the battery cell charging method provided in the embodiments of this application. Figure 8 ; Figure 9 This is a schematic diagram of the control processing unit provided in the embodiments of this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be described clearly and in detail below with reference to the accompanying drawings. Obviously, the embodiments in this application are only some embodiments, not all embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0019] It should be noted that when an element is described as "connected" to another element, it can be directly connected to the other element, or there can be one or more intermediate elements between them.

[0020] Furthermore, the technical features involved in the various embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0021] In related technologies, the safety control method for the charging process of battery cells is as follows: real-time acquisition of status parameters such as battery cell voltage, temperature, and charge; when the battery cell voltage, temperature, or charge reaches a preset alarm threshold, the system immediately stops charging, issues an alarm, or takes protective action.

[0022] For example, under normal charging conditions, the upper limit voltage for charging is generally set to 3.65V±0.05V and the maximum withstand temperature is 50℃. Once the monitored parameters reach the above critical threshold, the system will directly disconnect the charging path to complete passive protection.

[0023] However, the control schemes in related technologies have the following drawbacks: (1) The protection action is triggered entirely by real-time monitoring parameters touching a fixed critical threshold. It can only be remedied after the parameters such as cell voltage and temperature have exceeded the standard. The overall protection mode is a passive protection mode of post-incident handling. On the one hand, it is easy to trigger protection alarms frequently, which seriously reduces the user experience. On the other hand, the risk handling is delayed, and the safety hazards continue to accumulate, which can easily lead to further safety failures such as cell thermal runaway and thermal anomalies.

[0024] (2) Due to factors such as manufacturing process deviations and initial internal resistance differences, there are significant individual differences in the electrochemical characteristics, tolerance limits, and state change patterns of different cells and even the same cell throughout its entire life cycle at the charging end. Related technologies use fixed and uniform alarm thresholds to control all cells, which cannot adapt to the real-time health status and dynamic characteristics of a single cell. For aging cells with performance degradation and internal resistance deterioration, fixed thresholds easily keep them in the critical operating range for extended periods, continuously subjecting them to high voltage and high temperature conditions, thereby accelerating cell aging and shortening cell lifespan. Simultaneously, this accumulates long-term safety hazards, increasing the probability of thermal anomalies and overvoltage failures.

[0025] (3) The relevant technologies only make instantaneous judgments based on a single real-time sampling data, and do not have adaptive optimization capabilities, so they cannot adapt to the evolution of the entire battery cell life cycle. Long-term use will lead to a continuous decline in the accuracy of charging protection, an imbalance in risk identification sensitivity, difficulty in balancing charging safety and charging efficiency, and insufficient overall control robustness.

[0026] Based on this, this application provides a cell charging method based on historical charging end parameter memory, proactive risk identification, and adaptive adjustment to solve the above problems.

[0027] Please refer to Figure 1 , Figure 1 A flowchart illustrating a battery cell charging method provided in an embodiment of this application. Figure 1 As shown, the battery cell charging method includes the following steps S110 to S140.

[0028] Step S110: Obtain the characteristic parameters of the charging end of N consecutive historical charges that are immediately adjacent to the current charge in terms of time sequence. The characteristic parameters include the peak voltage rise rate and peak temperature rise rate of each charge, as well as the number of overvoltage alarms and overtemperature alarms of the N historical charges. The charging end is the time period from the satisfaction of condition one and / or condition two to the end of charging. Condition one is that the state of charge value of the cell is greater than the state of charge inflection point threshold. Condition two is that the voltage of the cell is greater than the inflection point critical potential of constant current charging. N is a positive integer.

[0029] Taking the current charge as the fifth charge, and using N=3 as an example. Specifically, before the current charge, there were a total of four charges. The three consecutive historical charges that are immediately adjacent to the current charge are the second to fourth charges.

[0030] The end of charging refers to the final period of a single complete charging process, which is the critical stage where the battery cell's condition is most prone to abnormalities and risks are most likely to accumulate. Specifically, it is defined as the entire period from the moment when any one or both of conditions one and two are met until the complete end of the current charging process.

[0031] Condition 1 is the state of charge inflection point condition, which means that the state of charge (SOC) value of the battery cell is greater than a preset inflection point threshold. This threshold is the critical SOC value in the middle and late stages of battery cell charging. When the SOC exceeds this value, the battery cell is about to leave the conventional constant current charging stage and enter the critical final stage of constant voltage charging, at which point the internal electrochemical state begins to change significantly. In some embodiments, the state of charge inflection point threshold is configured as any value in [75%, 85%].

[0032] Condition two is the voltage inflection point condition, meaning the real-time voltage of the battery cell is greater than the preset inflection point critical potential for constant current charging. This potential is the upper limit critical value of the voltage during the constant current charging stage of the battery cell. Once the voltage exceeds this value, the constant current charging stage ends, and the battery cell enters the final stage of high-voltage, low-current charging, which is highly susceptible to abnormal voltage and temperature fluctuations. The inflection point critical potential for constant current charging refers to the single-cell voltage value corresponding to the moment when the slope of the cell voltage change with SOC jumps under the standard temperature of 25℃ and rated constant current charging load conditions. This value is used to distinguish between the linear constant current charging stage and the nonlinear charging stage at the end of the charging process. In a specific embodiment, the battery cell is a lithium iron phosphate cell, and the inflection point critical potential for constant current charging is 3.4V.

[0033] Peak voltage rise rate refers to the maximum slope of the cell voltage change over time during the period at the end of each charge, and is used to quantify how fast the cell voltage changes at the end of the charge.

[0034] Peak temperature rise rate refers to the maximum slope of the cell temperature change over time during the period at the end of each charge, used to quantify the severity of the cell temperature rise at the end of the charge.

[0035] The number of overvoltage alarms refers to the cumulative number of times the cell voltage triggers the overvoltage alarm threshold within the time period at the end of N historical charging cycles.

[0036] The number of over-temperature alarms refers to the cumulative number of times the cell temperature triggers the over-temperature alarm threshold within the time period at the end of N historical charging cycles.

[0037] Specifically, this step is the foundational data collection step for risk prediction. It identifies the period at the end of each charge cycle with the highest risk for the battery cell and collects characteristic parameters from the most recent N historical charges adjacent to the current charge. The collected parameters include two core types of data: one is dynamic rate parameters reflecting the trend of changes in the battery cell's state, namely the peak voltage rise rate and peak temperature rise rate at the end of the charge cycle; the other is statistical parameters reflecting historical anomalies, namely the cumulative number of overvoltage and overtemperature alarms at the end of the N charges. This provides comprehensive, accurate, and targeted raw data support for the subsequent precise determination of the risk level.

[0038] Step S120: Determine the abnormal risk level based on the average of the peak rates of N historical charging cycles and the number of abnormal alarms, where the peak rate is the peak voltage rise rate or the peak temperature rise rate, the number of abnormal alarms is the number of overvoltage alarms or the number of overtemperature alarms, and the abnormal risk level is the overvoltage risk level or the overtemperature risk level.

[0039] The process involves calculating the arithmetic mean of the peak voltage rise rates corresponding to N historical charging cycles. This average peak voltage rise rate characterizes the overall voltage rise level at the end of the recent charging cycle, eliminating interference from occasional fluctuations in a single charge. Based on the average peak voltage rise rate across N historical charging cycles and the number of overvoltage alarms, an overvoltage risk level is determined. This overvoltage risk level characterizes the severity of any potential overvoltage risk during the current charging process and is categorized into low, medium, and high risk levels.

[0040] The arithmetic mean of the peak temperature rise rates corresponding to N historical charging cycles is calculated to obtain the average peak temperature rise rate. This average rate characterizes the overall temperature rise level of the battery cell at the end of a recent charge, eliminating the interference of occasional fluctuations in a single charge. Based on the average peak temperature rise rate corresponding to N historical charging cycles and the number of over-temperature alarms, the over-temperature risk level is determined. The over-temperature risk level characterizes the severity of the potential over-temperature hazard in the battery cell during this charging process, and is categorized into low risk, medium risk, and high risk levels.

[0041] Specifically, this step is the risk assessment step. This step abandons the traditional single threshold judgment logic and adopts a dual judgment dimension of trend rate combined with historical anomaly statistics. On the one hand, the average value of peak rate is used to judge the changing trend of cell voltage and temperature, and identify potential risks that have not yet reached the alarm threshold but have shown abnormal increases. On the other hand, the risk weight is adjusted by combining the number of historical alarms to quantify the degree of hidden danger of frequent cell anomalies. Finally, gradient-level overvoltage risk level and overtemperature risk level are output respectively.

[0042] In some embodiments, such as Figure 2 As shown, the specific implementation process of step S120 includes the following steps S210 to S230.

[0043] Step S210: When the average value is greater than the abnormal alarm threshold, or when the number of abnormal alarms is greater than the first alarm threshold, the abnormal risk level is determined to be high risk level.

[0044] Step S220: When the average value is greater than the first rate threshold and less than or equal to the abnormal alarm threshold, and the number of abnormal alarms is less than or equal to the first alarm threshold, the abnormal risk level is determined to be medium risk level.

[0045] Step S230: When the average value is less than or equal to the first rate threshold, the abnormal risk level is determined to be low risk level.

[0046] Among them, the abnormal alarm threshold is either an overvoltage alarm threshold or an overtemperature alarm threshold. The overvoltage abnormal alarm threshold is a preset rate threshold value in the voltage dimension, which indicates that the voltage rise rate at the end of the battery cell charging has approached the hardware overvoltage protection limit; the overtemperature abnormal alarm threshold is a preset rate threshold value in the temperature dimension, which indicates that the temperature rise rate at the end of the battery cell charging has approached the hardware overtemperature protection limit.

[0047] The first threshold is either the first overvoltage number threshold or the first overtemperature number threshold. The first overvoltage number threshold is a preset alarm count threshold based on voltage, indicating that the frequency of historical overvoltage anomalies has reached a level requiring close monitoring. The first overtemperature number threshold is a preset alarm count threshold based on temperature, indicating that the frequency of historical overtemperature anomalies has reached a level requiring close monitoring.

[0048] The first rate threshold is either a first voltage rate threshold or a first temperature rate threshold. The first voltage rate threshold is a preset upper limit reference value for normal rate in the voltage dimension, and its value is less than the overvoltage alarm threshold; the first temperature rate threshold is a preset upper limit reference value for normal rate in the temperature dimension, and its value is less than the overtemperature alarm threshold.

[0049] Specifically, the overvoltage risk level is determined to be high-risk when the arithmetic mean of the peak voltage rise rate is greater than the overvoltage alarm threshold, or when the number of overvoltage alarms is greater than the first overvoltage number threshold. The overvoltage risk level is determined to be medium-risk when the arithmetic mean of the peak voltage rise rate is greater than the first voltage rate threshold and less than or equal to the overvoltage alarm threshold, and the number of overvoltage alarms is less than or equal to the first overvoltage number threshold. The overvoltage risk level is determined to be low-risk when the arithmetic mean of the peak voltage rise rate is less than or equal to the first voltage rate threshold.

[0050] The overtemperature risk level is determined to be high-risk when the arithmetic mean of the peak temperature rise rate is greater than the over-temperature alarm threshold, or when the number of over-temperature alarms is greater than the first over-temperature number threshold. The overtemperature risk level is determined to be medium-risk when the arithmetic mean of the peak temperature rise rate is greater than the first temperature rate threshold but less than or equal to the over-temperature alarm threshold, and the number of over-temperature alarms is less than or equal to the first over-temperature number threshold. The overtemperature risk level is determined to be low-risk when the arithmetic mean of the peak temperature rise rate is less than or equal to the first temperature rate threshold.

[0051] Step S130: Adjust the upper limit of charging current and the constant voltage target voltage according to the overvoltage risk level, and adjust the upper limit of charging current and the maximum charging power according to the overtemperature risk level.

[0052] The upper limit of the charging current refers to the maximum charging current allowed to be output during the charging process of the battery cell. The upper limit of the charging current is a core parameter for regulating the charging rate and suppressing the temperature rise and voltage surge of the battery cell. The smaller the upper limit of the charging current, the smoother the charging rate and the more stable the battery cell.

[0053] The constant voltage target voltage refers to the preset target voltage value during the constant voltage charging stage of the battery cell. It directly determines the upper limit of the voltage at the end of the charging process, adapts to overvoltage risk control, and can effectively prevent voltage accumulation from exceeding the standard.

[0054] Maximum charging power refers to the maximum allowable charging power during the charging process of a battery cell. Maximum charging power is a parameter that integrates current and voltage control, primarily used to constrain the overall energy input rate of the charge, adapt to over-temperature risk regulation, and suppress abnormal temperature rise in the battery cell.

[0055] Specifically, this step achieves precise and adaptive management by matching corresponding control parameters to different risk types. For the determined overvoltage risk level, the upper limit of the adaptive charging current and the constant voltage target voltage are adjusted simultaneously to mitigate overvoltage risks from both the charging rate and voltage limit perspectives. For the determined overtemperature risk level, the upper limit of the charging current and the maximum charging power are adjusted accordingly to suppress cell temperature rise by reducing the energy input rate and slowing down the charging pace. Furthermore, the parameter adjustment range is matched to the risk level gradient; the higher the risk level, the greater the parameter adjustment range, achieving tiered and refined control.

[0056] In some embodiments, such as Figure 3 As shown, the specific implementation process of adjusting the upper limit of the charging current and the constant voltage target voltage according to the overvoltage risk level in step S130 includes the following steps S310 to S330.

[0057] Step S310: When the overvoltage risk level is high, reduce the upper limit of the charging current by a first percentage and reduce the constant voltage target voltage.

[0058] Step S320: When the overvoltage risk level is medium risk level, reduce the upper limit of the charging current by a second percentage while keeping the constant voltage target voltage unchanged, wherein the second percentage is less than the first percentage.

[0059] Step S330: When the overvoltage risk level is low, keep the upper limit of the charging current and the constant voltage target voltage unchanged.

[0060] Specifically, when the battery cell is determined to be at a high risk level of overvoltage, a voltage reduction and current limiting control is simultaneously implemented: on the one hand, the upper limit of the charging current is reduced by a percentage of the first percentage (the current upper limit of the charging current is reduced to I). MAX The adjusted upper limit of the charging current is (100% - A%) × I. MAX(where A% is the first percentage), slowing down the charging energy input speed and suppressing the rapid voltage rise; on the other hand, directly reducing the constant voltage target voltage and narrowing the upper limit of the voltage safety range at the end of the battery cell charging, thereby achieving bidirectional suppression of the overvoltage trend at the end of the battery cell charging.

[0061] Thus, in response to the serious overvoltage hazard, a dual protection method of high-proportion current limiting and voltage limiting is adopted to strongly suppress voltage surges at the end of battery cell charging, prevent the voltage from rapidly approaching the hardware protection threshold, and reduce the probability of lithium plating, overvoltage damage, and triggering forced power-off protection, thereby eliminating overvoltage safety hazards from the source.

[0062] If a battery cell is determined to be at a medium-risk level of overvoltage, the upper limit of the charging current will be slightly reduced by the second percentage point to slow down the charging rate and mitigate the voltage rise. At the same time, the standard constant voltage target voltage will remain unchanged to ensure that the battery cell can be charged normally. Furthermore, the reduction will be less than that for high-risk levels to minimize charging time and balance charging safety and charging efficiency.

[0063] If the battery cell is determined to be at a low risk level of overvoltage, the current upper limit of the charging current and the constant voltage target voltage will be maintained throughout the charging process, without any current limiting or voltage reduction correction.

[0064] In some embodiments, such as Figure 4 As shown, the specific implementation process of adjusting the upper limit of charging current and the maximum charging power according to the over-temperature risk level in step S130 includes the following steps S410 to S430.

[0065] Step S410: When the over-temperature risk level is high, reduce the upper limit of the charging current by a third percentage and limit the maximum charging power to less than the first power threshold.

[0066] Step S420: When the over-temperature risk level is medium risk level, reduce the upper limit of the charging current by a fourth percentage while keeping the maximum charging power unchanged, wherein the fourth percentage is less than the third percentage.

[0067] Step S430: When the over-temperature risk level is low, keep the upper limit of the charging current and the maximum charging power unchanged.

[0068] Specifically, when a battery cell is determined to be at a high risk level of overheating, current and power limiting regulation is implemented simultaneously: the upper limit of the charging current is reduced by a third percentage, thereby reducing the rate of heat generation in the battery cell from the source; at the same time, the maximum charging power of the whole machine is constrained not to exceed the first power threshold, limiting the total energy input during the charging stage, thus achieving a dual suppression of the temperature rise trend at the end of charging.

[0069] Thus, in response to severe thermal risks, the dual control method of significantly limiting current and capping power helps to reduce the heat generated per unit time of the battery cell, prevent the temperature rise from continuously approaching the hardware over-temperature protection threshold, and effectively avoid heat accumulation, battery cell thermal damage and forced power-off protection, thus eliminating over-temperature safety hazards from the source.

[0070] If a battery cell is determined to be at a medium-risk level for overheating, the upper limit of the charging current will be reduced by four percentage points to slow down the rate at which the cell heats up by slightly reducing the circuit current. At the same time, the original maximum charging power limit will remain unchanged to ensure the overall energy supply capacity of the charging system.

[0071] If the battery cell is determined to be at a low risk level of overheating, the current upper limit of charging current and maximum charging power will be maintained throughout the charging process, without any voltage reduction or power reduction correction.

[0072] Step S140: Execute the current charge based on the adjusted upper limit of charging current, constant voltage target voltage, and maximum charging power.

[0073] Specifically, the adjusted upper limit of charging current, constant voltage target voltage, and maximum charging power refer to the upper limit of charging current, constant voltage target voltage, and maximum charging power after executing step S130.

[0074] This step is the final execution step, applying the results of the preliminary risk assessment and parameter adjustment to the entire charging process. Using the upper limit of the charging current, the constant voltage target voltage, and the maximum charging power—adapted to the current risk state of the battery cell—as control benchmarks, the entire charging process is constrained. This achieves fully closed-loop adaptive control from parameter acquisition, risk assessment, parameter optimization to charging execution, completing intelligent and safe battery cell charging operations.

[0075] In this way, on the one hand, it enables proactive prediction and prevention of charging risks, overcoming the shortcomings of related technologies that can only provide post-event remedies and cannot identify hidden dangers. On the other hand, it can adaptively match charging control parameters based on the differences in historical charging characteristics of battery cells, adapting to the individual differences and aging states of different battery cells, preventing aging battery cells from being in critical operating conditions for a long time, delaying cell degradation, and improving charging safety. Furthermore, by introducing a historical charging data memory and analysis mechanism, and relying on multi-cycle historical data to continuously iterate and optimize the charging control strategy, the control logic can dynamically adapt to the performance evolution of the battery cell throughout its entire life cycle, significantly improving the accuracy of charging risk identification and the reliability of control.

[0076] In some embodiments, such as Figure 5 As shown, after performing step S140, the battery cell charging method further includes the following step S510.

[0077] Step S510: Determine the characteristic parameters of the charging end of the current charge.

[0078] After dynamically adjusting and completing the entire charging operation, the operation data of the charging end period in this charging process is captured, and all feature parameters corresponding to the charging end are calculated and extracted to complete the collection and storage of single charging sample features, so as to reserve the latest historical data for the risk level determination of the next round of charging.

[0079] In this way, the actual operational characteristics of each charging end are recorded in real time, and the historical charging database of the battery cells is continuously expanded and updated, realizing a closed-loop self-iteration of charging data. As a result, the sample basis can be updated accurately according to the aging process of the battery cells, so that the subsequent charging risk prediction results are more in line with the real-time health status of the battery cells, and the accuracy of risk identification and the adaptability of adaptive control can be continuously improved.

[0080] In some embodiments, such as Figure 6 As shown, the specific implementation process of step S510 includes the following steps S610 to S630.

[0081] Step S610: Obtain the charging condition parameters of the battery cell, including voltage, temperature and charge.

[0082] Step S620: When it is determined that condition one and / or condition two are met based on the charging condition parameters, the peak rate is determined based on the charging condition parameters.

[0083] Step S630: Determine the number of abnormal alarms based on whether charging has ended normally. Where no overvoltage alarm or overtemperature alarm occurs during charging, it corresponds to normal charging completion. If an overvoltage alarm or overtemperature alarm occurs during charging, it corresponds to charging not ending normally.

[0084] Normal charging completion means that no overvoltage or overtemperature alarms were triggered during the entire charging process, resulting in no protection interruption and the charging process being completed completely. Abnormal charging completion means that an overvoltage or overtemperature alarm was triggered during the charging process, causing the system to execute protection actions and interrupt charging.

[0085] Specifically, during the current charging process, the three basic operating parameters of the battery cell—real-time voltage, real-time temperature, and real-time power—are continuously collected in real time, and the status data of the entire charging process is completely retained.

[0086] When conditions one and / or two are met based on the charging operating parameters, the charging process is initiated at the end of the charging phase. Subsequently, all operating data within the charging end period are extracted, and the peak voltage rise rate and peak temperature rise rate corresponding to the charging end are calculated.

[0087] At the end of charging, the charging completion status is determined based on whether any overvoltage or overtemperature alarm signals were generated throughout the charging process: if no corresponding alarm was generated, charging is considered to have ended normally; if any type of alarm was generated, charging is considered to have not ended normally. Then, based on the charging completion status, the number of abnormal alarms is determined.

[0088] In some embodiments, such as Figure 7 As shown, the specific implementation process of determining the peak rate based on the charging condition parameters in step S620 includes the following steps S710 to S730.

[0089] Step S710: Determine the instantaneous rate corresponding to the Kth time point based on the ratio of the Kth difference to the Kth time interval during the charging process, so as to determine the M instantaneous rates during the charging process. Here, the Kth difference is the difference between the voltage at the Kth time point and the voltage at the (K-1)th time point or the difference between the temperature at the Kth time point and the temperature at the (K-1)th time point. The Kth time interval is the time interval between the Kth time point and the (K-1)th time point. The instantaneous rate is the instantaneous voltage rise rate or the instantaneous temperature rise rate. K and M are both integers, and 1≤K≤M.

[0090] Step S720: Perform a moving average operation on the M instantaneous rates to obtain J average rates, where J is an integer and 0 < J < M.

[0091] Step S730: Take the maximum value among the J average rates as the peak rate.

[0092] Here, time K-1 and time K refer to two consecutive adjacent data sampling times within the time period at the end of the charging process, with the timing sequence progressing sequentially.

[0093] The calculation process for the peak voltage rise rate is as follows: The instantaneous voltage rise rate R at time K U,K For: R U,K =ΔU K / Δt K =(U K -U K-1 ) / (t K -t K-1 ), where ΔU K Let Δt be the Kth difference. K For the Kth time interval, U K Let U be the voltage at time K. K-1 Let t be the voltage at time K-1. K For time k, t K-1 This is the (K-1)th time.

[0094] Iterate through all sampling points at the end of the charging process, and for each set of adjacent time-time samples, substitute them into the corresponding formula to solve for the instantaneous voltage rise rate R. U,K After traversing all K, M sets of instantaneous velocity sample sequences {R} are obtained. U,1 R U,2 , ..., R U,M}

[0095] Set the length of the sliding window to ω, and the moving average rate of the i-th group... for: After performing the moving average calculation, J average rates are obtained. The J average rates are: .

[0096] Peak voltage rise rate R U,peak for: , where max() means taking the maximum value.

[0097] The calculation process for the peak temperature rise rate is as follows: The instantaneous temperature rise rate T at time K U,K For: T U,K =ΔT K / Δt K =(T K -T K-1 ) / (t K -t K-1 ), where ΔT K Let Δt be the Kth difference. K For the Kth time interval, T K Let T be the temperature at time K. K-1 Let t be the temperature at time K-1. K For time k, t K-1 This is the (K-1)th time.

[0098] Iterate through all sampling points at the end of the charging process, and for each set of adjacent time-series sampling data, substitute the data into the corresponding formula to solve for the instantaneous temperature rise rate R. T,K After traversing all K, M sets of instantaneous velocity sample sequences {R} are obtained. T,1 R T,2 , ..., R T,M}

[0099] Set the length of the sliding window to ω, and the moving average rate of the i-th group... for: After performing the moving average calculation, J average rates are obtained. The J average rates are: .

[0100] Peak voltage rise rate R T,peak for: , where max() means taking the maximum value.

[0101] In some embodiments, such as Figure 8 As shown, the specific implementation process of step S630 includes the following steps S810 to S830.

[0102] Step S810: When charging ends normally, the number of abnormal alarms remains unchanged.

[0103] If no overvoltage or overtemperature protection is triggered during the charging process, the charging is considered to have ended normally. No new abnormal events are generated, and the original overvoltage alarm count and overtemperature alarm count remain unchanged. The counting accumulation operation is not performed.

[0104] Therefore, for healthy charging scenarios without abnormalities, the historical alarm statistics are not modified, avoiding interference from normal charging behavior with risk samples, ensuring that alarm counts only truthfully record valid abnormal operating conditions, and improving the objectivity of subsequent risk assessments.

[0105] Step S820: When the charging abnormality ends and the peak rate is greater than the first rate threshold, increment the number of abnormal alarms by one, where the first rate threshold is less than the abnormal alarm threshold, and the abnormal alarm threshold is the overvoltage alarm threshold or the overtemperature alarm threshold.

[0106] If charging is prematurely terminated due to an overvoltage / overtemperature alarm, and the peak rate at the end of the charging process is greater than the first rate threshold, it indicates that the interruption was caused by the deterioration of the cell's own condition, which is a valid abnormal sample. The number of abnormal alarms of the corresponding type will be incremented by one.

[0107] If charging is prematurely terminated due to an overvoltage alarm, and the peak voltage rise rate at the end of this charging cycle is greater than the first voltage rate threshold, it indicates that the charging interruption was caused by the deterioration of the cell voltage rise characteristics, which is a valid overvoltage anomaly sample, and the overvoltage alarm count is incremented by one.

[0108] If charging is prematurely terminated due to an over-temperature alarm, and the peak temperature rise rate at the end of this charging cycle is greater than the first temperature rate threshold, it indicates that the charging interruption was caused by the deterioration of the cell temperature rise characteristics, which is a valid over-temperature anomaly sample, and the over-temperature alarm count is incremented by one.

[0109] Step S830: When the charging ends abnormally and the peak rate is less than or equal to the first rate threshold, the characteristic parameters of the charging end of this charging are determined to be invalid parameters.

[0110] Invalid parameters refer to characteristic parameters such as the peak voltage rise rate and peak temperature rise rate obtained from the calculation of the charging end. These are determined to be false data generated by random interference and are not stored in the historical sample library or used in subsequent risk calculations.

[0111] Specifically, if charging is prematurely terminated due to an overvoltage / overtemperature alarm, and the peak rate at the end of the charging process is less than or equal to the first rate threshold, it indicates that the interruption was not caused by the deterioration of the cell's own condition and is therefore an invalid sample that should be discarded.

[0112] If charging is terminated prematurely due to an overvoltage alarm, but the peak voltage rise rate at the end of the current charging is less than or equal to the first voltage rate threshold, it is determined that the overvoltage protection was caused by sampling jitter or instantaneous interference, rather than by cell voltage characteristic degradation, and all characteristic parameters at the end of the current charging are marked as invalid parameters.

[0113] If charging is terminated prematurely due to an over-temperature alarm, but the peak temperature rise rate at the end of this charging period is less than or equal to the first temperature rate threshold, it is determined that the over-temperature protection was caused by external disturbances or sensor noise, rather than by cell temperature characteristic degradation, and all characteristic parameters at the end of this charging period are marked as invalid parameters.

[0114] In this way, on the one hand, voltage and temperature abnormalities are counted separately and independently, accurately distinguishing the two types of faults: cell overvoltage degradation and excessively rapid temperature rise; on the other hand, only actual cell degradation events with excessive rates are counted, filtering out invalid alarm records caused by accidental disturbances, providing accurate quantitative statistical basis for overvoltage and overtemperature risk classification, and reducing the probability of misjudgment.

[0115] Understandable, Figures 6 to 8 This paper demonstrates the complete extraction process of characteristic parameters at the end of the current charge. The parameter acquisition, rate calculation, and anomaly counting logic is universal. For any previous historical charge in the time series, the process of obtaining the characteristic parameters at the end of the charge uses the exact same processing logic and calculation rules. Only the corresponding operating condition sampling data for each charge needs to be replaced to complete the extraction of the corresponding characteristic parameters.

[0116] Please refer to Figure 9 , Figure 9 This is a schematic diagram of the control processing unit provided in an embodiment of this application. The control processing unit 900 can be a microcontroller unit (MCU) or a digital signal processing (DSP) controller, etc.

[0117] The control processing unit 900 includes at least one processor 910 and a memory 920. The memory 920 can be built into the control processing unit 900 or external to the control processing unit 900. The memory 920 can also be a remotely configured memory connected to the control processing unit 900 via a network.

[0118] Memory 920, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules. Memory 920 may include a program storage area and a data storage area, wherein the program storage area may store the operating system and application programs required for at least one function; the data storage area may store data created based on the use of the terminal, etc. Furthermore, memory 920 may include high-speed random access memory and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In some embodiments, memory 920 may optionally include memory remotely located relative to processor 910, and these remote memories can be connected to the terminal via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0119] The processor 910 performs various functions of the terminal and processes data by running or executing software programs and / or modules stored in the memory 920 and calling data stored in the memory 920, thereby performing overall monitoring of the terminal, such as implementing the battery charging method described in any embodiment of this application.

[0120] There can be one or more processors 910. Figure 9 The example provided uses a processor 910. The processor 910 and memory 920 can be connected via a bus or other means. The processor 910 may include a central processing unit (CPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a controller, a field-programmable gate array (FPGA) device, etc. The processor 910 can also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration.

[0121] This application also provides an energy storage system. The energy storage system includes at least one battery cell and a control processing unit 900 in any embodiment of this application. The control processing unit 900 is electrically connected to the battery cell to control the charging process of the battery cell.

[0122] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

[0123] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to 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 battery cell, characterized in that, include: The characteristic parameters of the charging end of N consecutive historical charges that are immediately adjacent to the current charge are obtained. The characteristic parameters include the peak voltage rise rate and peak temperature rise rate of each charge, as well as the number of overvoltage alarms and overtemperature alarms of the N historical charges. The charging end is the time period from the satisfaction of condition one and / or condition two to the end of charging. Condition one is that the state of charge value of the cell is greater than the state of charge inflection point threshold. Condition two is that the voltage of the cell is greater than the inflection point critical potential of constant current charging. N is a positive integer. The abnormal risk level is determined based on the average peak rate of N historical charging cycles and the number of abnormal alarms, wherein the peak rate is the peak voltage rise rate or the peak temperature rise rate, the number of abnormal alarms is the number of overvoltage alarms or the number of overtemperature alarms, and the abnormal risk level is the overvoltage risk level or the overtemperature risk level. The upper limit of the charging current and the constant voltage target voltage are adjusted according to the overvoltage risk level, and the upper limit of the charging current and the maximum charging power are adjusted according to the overtemperature risk level. The current charging cycle is performed based on the adjusted upper limit of the charging current, the constant voltage target voltage, and the maximum charging power.

2. The cell charging method according to claim 1, characterized in that, After performing the step of performing the current charge based on the adjusted upper limit of the charging current, the constant voltage target voltage, and the maximum charging power, the method further includes: Determine the characteristic parameters of the charging end of the current charge.

3. The cell charging method according to claim 2, characterized in that, The steps for determining the characteristic parameters of the charging end of the current charge include: Obtain the charging condition parameters of the battery cell, wherein the charging condition parameters include voltage, temperature and charge. When it is determined that condition one and / or condition two are satisfied based on the charging condition parameters, the peak rate is determined based on the charging condition parameters. The number of abnormal alarms is determined based on whether charging ends normally. Specifically, if no overvoltage or overtemperature alarm occurs during charging, it indicates that charging has ended normally. If an overvoltage or overtemperature alarm occurs during charging, it indicates that charging has not ended normally.

4. The cell charging method according to claim 3, characterized in that, The step of determining the peak rate based on the charging condition parameters includes: The instantaneous rate at time K is determined by the ratio of the Kth difference to the Kth time interval during the charging process, thereby determining the M instantaneous rates during the charging process. Here, the Kth difference is the difference between the voltage at time K and the voltage at time K-1 or the difference between the temperature at time K and the temperature at time K-1, the Kth time interval is the time interval between time K and time K-1, and the instantaneous rate is the instantaneous voltage rise rate or the instantaneous temperature rise rate. K and M are both integers, and 1≤K≤M. Perform a moving average operation on M instantaneous rates to obtain J average rates, where J is an integer and 0 < J < M; The maximum value among the J average rates is taken as the peak rate.

5. The cell charging method according to claim 3, characterized in that, The step of determining the number of abnormal alarms based on whether charging has ended normally includes: The number of abnormal alarms remains unchanged when charging ends normally; When charging abnormally ends and the peak rate is greater than the first rate threshold, the number of abnormal alarms is incremented by one, wherein the first rate threshold is less than the abnormal alarm threshold, and the abnormal alarm threshold is an overvoltage alarm threshold or an overtemperature alarm threshold. If charging ends abnormally and the peak rate is less than or equal to the first rate threshold, the characteristic parameters of the charging end of that charging session are determined to be invalid parameters.

6. The cell charging method according to claim 1, characterized in that, The steps for determining the anomaly risk level based on the average peak rate of N historical charging cycles and the number of abnormal alarms include: When the average value is greater than the abnormal alarm threshold, or when the number of abnormal alarms is greater than the first alarm threshold, the abnormal risk level is determined to be a high risk level. When the average value is greater than the first rate threshold and less than or equal to the abnormal alarm threshold, and the number of abnormal alarms is less than or equal to the first number threshold, the abnormal risk level is determined to be a medium risk level. When the average value is less than or equal to the first rate threshold, the abnormal risk level is determined to be a low risk level.

7. The cell charging method according to claim 1 or 6, characterized in that, The steps of adjusting the upper limit of the charging current and the constant voltage target voltage according to the overvoltage risk level include: When the overvoltage risk level is high, the upper limit of the charging current is reduced by a first percentage and the constant voltage target voltage is reduced; When the overvoltage risk level is medium risk level, the upper limit of the charging current is reduced by a second percentage while the constant voltage target voltage remains unchanged, wherein the second percentage is less than the first percentage; When the overvoltage risk level is low, the upper limit of the charging current and the constant voltage target voltage remain unchanged.

8. The cell charging method according to claim 1 or 6, characterized in that, The steps of adjusting the upper limit of the charging current and the maximum charging power according to the over-temperature risk level include: When the over-temperature risk level is high, the upper limit of the charging current is reduced by a third percentage and the maximum charging power is limited to be less than a first power threshold. When the over-temperature risk level is medium risk level, the upper limit of the charging current is reduced by a fourth percentage while the maximum charging power remains unchanged, wherein the fourth percentage is less than the third percentage; When the over-temperature risk level is low, the upper limit of the charging current and the maximum charging power remain unchanged.

9. A control processing unit, characterized in that, include: At least one processor and memory; The memory is coupled to the processor and is used to store instructions or programs that, when executed by the at least one processor, cause the at least one processor to perform the cell charging method as described in any one of claims 1-8.

10. An energy storage system, characterized in that, It includes at least one battery cell and a control processing unit as described in claim 9, the control processing unit being electrically connected to the battery cell to control the charging process of the battery cell.

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