A dynamic control method for lithium battery energy storage system

Abstract

The present invention belongs to the field of battery energy storage control technology, and specifically discloses a method for dynamic control of a lithium battery energy storage system, the method comprising: importing the initial state of charge, rated capacity and charging setting parameters of the target battery group; collecting the current cumulative charging time and charging parameters of the target battery group, and storing them in a charging information library; verifying the charging status, if the verification result is safe, continuing to execute the charging instruction according to the charging setting parameters, otherwise confirming the charging control type of the target battery group and confirming the adjustment index value, and providing feedback, and then controlling the charging of the target battery group. The present invention effectively solves the problem of insufficient safety assurance of the current battery energy storage process, and can ensure that the battery is charged in the best state, thereby avoiding the occurrence of overcharging or over-discharging, thereby extending the battery's service life and improving its performance, while also ensuring the safety and controllability of the charging process.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery energy storage control and relates to a dynamic control method for a lithium battery energy storage system. Background Art

[0002] Lithium battery energy storage system is a system that uses lithium-ion batteries as energy storage media to store and release electrical energy through the charging and discharging process. It plays a vital role in the modern energy field, especially in renewable energy integration, power system balance, distributed energy management and microgrid applications. Therefore, in order to ensure the stability of the actual application of the energy storage system, its energy storage process needs to be dynamically controlled.

[0003] Energy storage system management and control mainly involves full process control of energy storage batteries, such as control of temperature, charging and discharging time, charging and discharging power during the charging and discharging process.

[0004] Prior art, such as the energy storage control method, device and energy storage control system disclosed in the Chinese invention patent application with application publication number CN113141038A, first obtains the state of charge of the energy storage system, and then controls the charging or discharging of the energy storage battery according to the state of charge of the energy storage system and the first remaining capacity of the battery, the second remaining capacity of the battery, the third remaining capacity of the battery and the fourth remaining capacity of the battery. It can reasonably control the charging and discharging of the energy storage battery in the energy storage system, thereby ensuring the service life of the energy storage battery.

[0005] Another example of the prior art is the charging and discharging power control method and device for the energy storage system disclosed in the Chinese invention patent application with application publication number CN116566020A, which obtains the peak power consumption period, the valley power consumption period, the energy storage capacity corresponding to the energy storage converter, the rated power of the input transformer and the first power of the input transformer, and adjusts the charging and discharging power of the energy storage converter by the above parameters according to the time period at the current moment. By adopting the above method, the charging and discharging power of the energy storage converter can be adjusted differently when the user load is constantly changing, which can not only prevent the input transformer from being overloaded, but also improve the operating efficiency of the input transformer, thereby reducing the customer's input transformer loss and increasing the incremental revenue for the customer.

[0006] Obviously, the above two technical solutions still have the following shortcomings: 1. Insufficient safety and redundancy design: Although the above technical solutions have taken safety control into consideration to a certain extent, the emergency response and redundancy design in large-scale deployment scenarios and in situations such as battery failure and overload still need to be strengthened, such as the safety margin setting of the charging process.

[0007] 2. Insufficient reliability of battery status assessment: Currently, battery power is adjusted only according to current capacity to control battery life, without combining information on changes in past charging processes, such as the environment and degree of discharge during the charging and discharging cycle, for comprehensive assessment, resulting in insufficient accuracy of battery status assessment.

[0008] 3. Insufficient safety assurance of the battery energy storage process: Currently, the factors considered in the battery energy storage process are relatively simple, such as single environment and single power analysis. There is no comprehensive analysis of the various factors that interfere with and influence each other in the charging process, which makes the safety assurance of the energy storage process still lacking, and thus the reliability and stability of the charging process cannot be guaranteed. Summary of the invention

[0009] In view of this, in order to solve the problems raised in the above background technology, a dynamic control method for a lithium battery energy storage system is now proposed.

[0010] The objective of the present invention can be achieved through the following technical solutions: The present invention provides a method for dynamic control of a lithium battery energy storage system, including: S1, charging setting import: recording the current charging battery group as the target battery group, importing the initial state of charge, rated capacity and charging setting parameters of the target battery group, wherein the charging setting parameters include setting the charging rate and setting the charging voltage margin.

[0011] S2. Charging parameter collection and storage: collect the current cumulative charging time and charging parameters of the target battery pack and store them in the charging information library.

[0012] S3, charging status verification: extract the cumulative charging tracking log of the target battery pack from the charging information library, and verify the charging status based on it. If the verification result is safe, continue to execute the charging instruction according to the charging setting parameters, otherwise execute step S4.

[0013] S4. Charging control analysis: confirming the charging control type of the target battery pack and confirming the adjustment index value, wherein the charging control type is one or more of the charging safety margin and the charging rate.

[0014] S5, charging control execution: feeding back the charging control type and adjustment index value of the target battery group to the charging control terminal of the target battery group, and performing charging control on the target battery group.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention collects the charging parameters of the battery pack and verifies the charging status and analyzes the charging control in combination with the accumulated charging tracking log of the battery pack, thereby ensuring that the battery is charged in the best condition and avoiding overcharging or over-discharging, thereby extending the battery life and improving its performance. At the same time, it also ensures the safety and controllability of the charging process, thereby further improving the management effect of the charging process.

[0016] (2) The present invention verifies the charging status by analyzing the temperature rise state, charge state and resistance state of the battery pack, thereby improving the accuracy of the battery charging status, thereby ensuring the reliability and authenticity of the charging status verification result, and also improving the verification coverage of the battery pack charging status. On another level, by comprehensively analyzing the temperature rise state, charge state and resistance state, reliable data support can be provided for maximizing charging efficiency and safety, which is convenient for the subsequent formulation of more scientific charging strategies and long-term maintenance plans.

[0017] (3) The present invention effectively solves the problem of insufficient safety assurance of the current battery energy storage process by comprehensively analyzing the temperature rise state, charge state and resistance state of the battery pack when confirming the charging control type of the target battery pack and confirming the adjustment index value, avoids the singleness of the current energy storage one-way analysis, and fully considers the interference and correlation between various factors in the charging process, thereby further ensuring the safety of the charging process as well as the reliability and stability of the charging process.

[0018] (4) The present invention effectively solves the current problems of insufficient charging safety and redundant design by considering the charging safety margin and charging rate when controlling the charging process, provides strong guarantees for emergency response and redundant design in scenarios of large-scale deployment, battery failure, overload, etc., and ensures the rationality and standardization of the charging safety margin and charging rate.

[0019] (5) The present invention analyzes the temperature rise state, charge state and resistance state of each battery cell in the battery pack, fully considering the differences and uniqueness of different battery cells in the battery pack, thereby ensuring the representativeness of the battery pack analysis results. At the same time, when analyzing the resistance state, by combining the accumulated charging tracking log, the health deviation trend factor of the target battery pack is set, and then the reference resistance value is set, which fully considers the change information of the battery pack's past charging process and improves the effectiveness, reliability and accuracy of the battery state assessment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0021] Figure 1 The present invention is a schematic flow chart of the steps for implementing the method. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] See also Figure 1 As shown, the present invention provides a method for dynamic control of a lithium battery energy storage system, the method comprising: S1, charging setting import: recording the current charging battery group as the target battery group, importing the initial state of charge, rated capacity and charging setting parameters of the target battery group, the charging setting parameters comprising setting the charging rate and setting the charging voltage margin.

[0024] S2. Charging parameter collection and storage: collect the current cumulative charging time and charging parameters of the target battery pack and store them in the charging information library.

[0025] Specifically, the charging parameters include but are not limited to the charging temperature, current and voltage of each battery cell at each charging time point.

[0026] It should be added that the charging temperature is acquired by a temperature sensor built into the battery cell, the current is monitored by a current sensor built into the battery cell, and the voltage is monitored by a voltage sensor built into the battery cell.

[0027] S3, charging status verification: extract the cumulative charging tracking log of the target battery pack from the charging information library, and verify the charging status based on it. If the verification result is safe, continue to execute the charging instruction according to the charging setting parameters, otherwise execute step S4.

[0028] S4. Charging control analysis: confirming the charging control type of the target battery pack and confirming the adjustment index value, wherein the charging control type is one or more of the charging safety margin and the charging rate.

[0029] The embodiments of the present invention effectively solve the current problems of insufficient charging safety and redundant design by considering the charging safety margin and charging rate when controlling the charging process, provide strong guarantees for emergency response and redundant design in scenarios of large-scale deployment, battery failure, overload, etc., and ensure the rationality and standardization of the charging safety margin and charging rate.

[0030] S5, charging control execution: feeding back the charging control type and adjustment index value of the target battery group to the charging control terminal of the target battery group, and performing charging control on the target battery group.

[0031] In a specific embodiment, in order to ensure the long-term safety and reliability of the battery, a certain safety margin is usually reserved when setting the voltage upper limit value. This means that the actual voltage upper limit value may be slightly lower than the maximum safe voltage of the battery. At the same time, in order to ensure the stability of charging, the charging rate is usually controlled. Therefore, when the present invention controls the battery charging safety level, it selects the charging safety margin and the charging rate to control in two dimensions to ensure the safety and stability of charging.

[0032] It should be added that the charging safety margin usually refers to the difference between the actual charging voltage and the maximum allowable charging voltage of the battery during the battery charging process. The safety margin is mainly used to protect the battery from overcharging damage and ensure the battery life and safety. For example, if the maximum allowable charging voltage of a lithium-ion battery is 4.2V, and the actual charging control circuit sets the charging cut-off voltage to 4.1V, then 0.1V is the charging safety margin.

[0033] Furthermore, the charging status verification is performed in the step S3, including: S31, extracting the charging temperature of each battery unit at each charging time point from the charging parameters.

[0034] S32, traversing the charging temperature of each battery cell at each charging time point, extracting the charging time point at which the highest temperature first appears for each battery cell, and recording it as the charging temperature peak time point.

[0035] S33, taking the interval between the charging temperature peak time point and the first charging time point as the temperature rise time, and calculating the temperature rise state consistency of the target battery pack based on this, recorded as .

[0036] S34, extracting the current of each battery cell at each charging time point from the charging parameters, and calculating the state of charge of each battery cell at each charging time point by a coulomb counting method.

[0037] It should be added that the specific calculation formula for calculating the state of charge of each battery cell at each charging time point by the coulomb counting method is as follows: , Indicates The battery cell is The state of charge at each charging time point is Indicates The battery cell is The current at each charging time point, represents the initial state of charge, Indicates the rated capacity, Indicates the battery cell number, , Indicates the charging time point number, .

[0038] In a specific embodiment, the initial state of charge refers to the known state of charge of the battery at a certain moment, which is usually measured or estimated before the battery is used, such as fully charging the battery to 100% of its rated capacity, or fully discharging it to 0%. In this case, the initial SoC is 100% or 0%, respectively.

[0039] S35, constructing a state-of-charge characteristic curve of each battery cell with the charging time point as the horizontal coordinate and the state-of-charge as the vertical coordinate, and calculating the state-of-charge conformity of the target battery pack based on the state-of-charge characteristic curve of each battery cell, which is recorded as .

[0040] S36, extracting the voltage of each battery cell at each charging time point from the charging parameters, and calculating the resistance of each battery cell at each charging time point , and then calculate the resistance state matching degree of the target battery pack, recorded as .

[0041] S37, Settings , and For each verification indicator value, if all verification indicator values ​​are greater than or equal to 0, safety is taken as the verification result. If there is a verification indicator value less than 0, unsafe is taken as the verification result.

[0042] The embodiment of the present invention verifies the charging status by analyzing the battery pack from three dimensions: temperature rise state, charge state and resistance state. This can improve the accuracy of the battery charging status, thereby ensuring the reliability and authenticity of the charging status verification result, while also improving the verification coverage of the battery pack charging status. On another level, the comprehensive temperature rise state, charge state and resistance state can provide reliable data support for maximizing charging efficiency and safety, which is convenient for the subsequent formulation of more scientific charging strategies and long-term maintenance plans.

[0043] It can be understood that the statistical temperature rise state consistency of the target battery pack in step S33 includes: A1, calculating the variance of the temperature rise time of each battery cell, and taking the calculation result as the temperature rise difference, recorded as .

[0044] A2. Compare the temperature rise time of each battery cell with the preset reference temperature rise time interval of the target battery pack. If the temperature rise time of a battery cell is within the reference temperature rise time interval, record the battery cell as a normal temperature rise cell.

[0045] A3. Count the number of cells with normal temperature rise and compare it with the number of battery cells. The ratio is taken as the temperature rise compliance ratio and recorded as .

[0046] A4. Statistical consistency of temperature rise status of target battery pack , , is the set allowable battery cell temperature rise difference, To set the reference temperature rise compliance ratio.

[0047] It should be added that Indicated in and Select the minimum value.

[0048] In a specific embodiment, when When the value is 0, it indicates that the temperature rise time of each battery cell is consistent, that is, the difference between each battery cell is small. The smaller the difference between the battery cells and the higher the temperature rise compliance ratio, the more consistent the temperature rise state of the battery pack. It can be set with 0 as the reference value. Specifically, You can set the value to 0.5. It is set according to the experience of temperature rise assessment. Specifically, The value can be 0.95.

[0049] It should be explained that the battery pack is composed of multiple battery cells connected in series or in parallel, and each battery cell is usually of the same model or at least has similar specifications and performance characteristics. In some specific applications, in order to ensure the stability and performance of the battery pack, all battery cells will have exactly the same specifications and parameters. This can avoid problems caused by performance differences of individual battery cells, such as voltage imbalance between battery cells, thereby extending the life and performance of the entire battery pack. The default specifications and performance characteristics of the battery cells inside the battery pack of the present invention are consistent in the initial state.

[0050] Understandably, calculating the SOC matching degree of the target battery pack in step S35 includes: B1, extracting a reference SOC characteristic curve of the target battery pack from a charging information database, and recording it as a reference curve.

[0051] It should be added that the reference state-of-charge characteristic curve of the target battery pack is usually provided by the battery manufacturer.

[0052] B2. Overlap the state of charge characteristic curve of each battery cell with the reference curve to obtain the overlap curve length of each battery cell.

[0053] B3. Compare the length of the overlap curve of each battery cell with the length of the state of charge characteristic curve of each battery cell, and record the ratio as the overlap curve ratio. .

[0054] B4. Select a curve segment under the current accumulated charging time from the reference curve and record it as a reference curve segment.

[0055] B5. Extract the slope of the state of charge characteristic curve as the state of charge change rate of each battery cell and record it as , and at the same time extract the slope of the reference curve segment as the reference charge state change rate .

[0056] B6. Set the first evaluation variable and the second evaluation variable of each battery cell, respectively and .

[0057] Specifically, set The first evaluation variable for each battery cell , For the preset reference coincidence curve ratio, set The second evaluation variable for each battery cell , is the preset state of charge change rate difference.

[0058] In a specific embodiment, It reflects the similarity between the curves. Specifically, The value can be 0.8. The details can be extracted from the technical manual of the target battery. For example, The value can be 0.1.

[0059] B7. Count the charge state consistency of each battery cell , , , and To set the conditions, express and Established or and Established, express and Established, express and Established.

[0060] B8. Filter out the minimum value from the state of charge consistency of each battery cell as the state of charge consistency of the target battery pack.

[0061] It can also be understood that the calculation of the resistance state conformity of the target battery pack in step S36 includes: E1, extracting the unit change of the target battery internal resistance with temperature from the charging information library, recorded as , and the charging temperature of each battery cell at each charging time point is recorded as .

[0062] E2. Count the corrected resistance value of each battery cell at each charging time point, recorded as , , is the set reference temperature.

[0063] It should be added that Indicates that between 0 and Select the maximum value from the above, and multiply the selected maximum value by the unit change of the target battery internal resistance with temperature. The value of The battery cell is The resistance value increased at each charging time point.

[0064] In a specific embodiment, in order to make the internal resistance data comparable, we can use a reference temperature, such as 25°C for calibration, and extract the unit change of the target battery internal resistance with temperature from the charging information library, such as 0.01OΩ per °C. Assuming that the charging temperature at a certain charging time point is 30°C, the change of the battery internal resistance with temperature is 0.05Ω. Because high temperature will increase the resistance, when the heating temperature does not exceed the reference temperature, there is no temperature-level compensation resistance value.

[0065] E3. Set the reference resistance value of each battery cell at each charging time point, recorded as .

[0066] E4. Compare the corrected resistance value of each battery cell at each charging time point with the reference resistance value.

[0067] E5. If the corrected resistance value of a battery cell at a certain charging time point is less than or equal to the reference resistance value, the charging time point is recorded as a resistance matching time point.

[0068] E6. Count the number of resistance matching time points of each battery cell and compare it with the number of charging time points. The ratio is used as the resistance matching degree of each battery cell, which is recorded as ,Will As the resistance state match of the target battery pack, To set the reference resistance fit.

[0069] Specifically, the setting of the reference resistance value of each battery cell at each charging time point in step E3 includes: E31, extracting the cumulative number of charge and discharge cycles from the cumulative charging tracking log of the target battery pack, recorded as .

[0070] E32. Extract the temperature, current and voltage at each charging time point during each cumulative charging from the cumulative charging tracking log.

[0071] E33, according to , and The calculation method is to calculate the verification index values ​​of each cumulative charge in turn, and set the health deviation trend factor of the target battery pack. .

[0072] Among them, setting a healthy deviation trend factor includes: recording the accumulated charging with a verification index value less than 0 as deviation charging, and recording the verification index value less than 0 as a deviation index value.

[0073] Count the number of deviation charging times and compare it with the cumulative number of charging times. The ratio is recorded as the deviation charging ratio. .

[0074] The number of deviation index values ​​corresponding to each deviation charging is counted and compared with the number of verification index values, and the ratio is recorded as the deviation index ratio.

[0075] The deviation index ratio corresponding to each deviation charging is averaged to obtain the deviation charging index ratio .

[0076] Setting the health deviation trend factor , , , and The reference charge and discharge cycle number, deviation charge ratio and deviation charge index ratio are set respectively. is a natural constant.

[0077] It should be added that the setting formula of the health deviation trend factor is obtained by referring to the Sigmoid function. The purpose is to map the value of the health deviation trend factor to between 0 and 1, and to ensure that the health deviation trend factor increases with the increase of the independent variable.

[0078] In a specific embodiment, , and The specific value of is mainly extracted from the technical manual of the target battery. And exemplarily, and The value can be 0.3.

[0079] E34. Extract the reference resistance of the target battery pack from the charging information database, denoted as , count the reference resistance value of each battery cell at each charging time point , , is the supplementary resistance value corresponding to the set unit health deviation trend factor, The temperature reference reduction ratio is set corresponding to the set unit health deviation trend factor.

[0080] In a specific embodiment, Indicates the corrected reference temperature. When the health deviation of the target battery pack is large, that is, when the health status is poor, the battery tends to age, and the aged battery is more sensitive to temperature changes. Adjusting the reference temperature can help better capture these changes. At this time, the reference temperature needs to be lowered to compensate for this change, ensuring that the temperature-corrected internal resistance value can more accurately reflect the true state of the battery.

[0081] It should be added that the supplementary resistance value corresponding to the unit health deviation trend factor and the set temperature reference reduction ratio corresponding to the unit health deviation trend factor can be extracted from sources such as the technical manual of the target battery and the performance test technical table of the target battery.

[0082] The embodiment of the present invention analyzes the temperature rise state, charge state and resistance state of each battery cell in the battery pack, fully considering the differences and uniqueness of different battery cells in the battery pack, thereby ensuring the representativeness of the battery pack analysis results. At the same time, when analyzing the resistance state, by combining the accumulated charging tracking log, the health deviation trend factor of the target battery pack is set, and then the reference resistance value is set, which fully considers the change information of the battery pack's past charging process and improves the effectiveness, reliability and accuracy of the battery state assessment.

[0083] Furthermore, in step S4, the charging control type of the target battery pack is confirmed, including: traversing the temperature rise state consistency of the target battery pack , Charge state consistency The consistency with the resistance state .

[0084] like Established and and are all greater than or equal to 0, and the charging safety margin is used as the charging control type of the target battery group.

[0085] like and Established or and The charging rate is established as the charging control type of the target battery pack.

[0086] like , and All less than 0 or and Or and It is established that the charging safety margin and charging rate are used as the charging control type of the target battery pack.

[0087] In a specific embodiment, the temperature rise state conformity of the battery reflects the temperature change of the battery during the charging process. If the temperature rises too quickly or exceeds the safety threshold, this may indicate that the charging rate is too fast. In this case, the charging rate may need to be reduced to avoid overheating. The charge state conformity refers to the degree of proximity of the battery's charging state to the ideal state. If the battery's state of charge changes rapidly, it indicates that the current charging rate may be unstable or inappropriate, and the charging rate needs to be adjusted to ensure that the battery can be charged more smoothly. The resistance state conformity refers to the degree of proximity between the resistance value and the reference value. The internal resistance of the battery will increase with the use time and the number of charges. High resistance may lead to reduced battery charging efficiency and increased heat generation. If the resistance value is high, it may be necessary to consider increasing the safety margin of charging to ensure that the charging current can be charged into the battery without exceeding the battery capacity. Therefore, setting the temperature rise state conformity and the charge state conformity is an associated evaluation indicator of the charging rate, and setting the resistance state conformity is an associated evaluation indicator of the charging margin.

[0088] The embodiment of the present invention effectively solves the problem of insufficient safety assurance of the current battery energy storage process by comprehensively analyzing the temperature rise state, charge state and resistance state of the battery group when confirming the charging control type of the target battery group and confirming the adjustment index value, avoids the singleness of the current energy storage unidirectional analysis, and fully considers the interference and correlation between various factors in the charging process, thereby further ensuring the safety of the charging process as well as the reliability and stability of the charging process.

[0089] Furthermore, in step S4, the adjustment index value is confirmed, including: U1, when the charging control type is the charging safety margin, the setting charging safety margin is recorded as , calculate and adjust the charging safety margin , , is the upper limit of the charging safety margin. As an adjustment indicator value.

[0090] It should be added that It reflects the increase rate of the charging safety margin. Too large a safety margin may cause the battery to not be fully charged, affecting the battery's efficiency. Too small a safety margin may increase the risk of overcharging the battery, shorten the battery life, or even cause a safety accident. Therefore, an upper limit value for the charging safety margin is set. The charging safety margin adjustment range is delineated to ensure the rationality of the charging safety margin setting, and in a specific embodiment, the charging safety margin upper limit value Can be extracted from the technical manual of the target battery.

[0091] U2. When the charging control type is charging rate, the set charging rate is recorded as , calculate and adjust the charging rate , , To set the reference charging rate lower limit, As an adjustment indicator value.

[0092] It should be added that The value of reflects the reduction ratio of the charging rate. Indicates that between 1 and Select the minimum value among When the value of is greater than or equal to 1, 1 is used as the reduction ratio of the charging rate, otherwise As the reduction factor of the charging rate, the minimum function is set to ensure that the adjustment of the charging rate does not exceed the set range.

[0093] It is also necessary to add that Points between 0 and Select the maximum value when When the difference is less than or equal to 0, 0 is taken as the final result. When it is greater than 0, As a final result, Similarly, set and Because when and Established or and The charging rate is the target battery pack charging control type, that is, when Under these conditions, there is only ,only as well as and These three situations are true at the same time. In order to distinguish the interference in these three situations, we set or When the reduction ratio is set to 0, the temperature rise state consistency and the charge state consistency are avoided. In a specific embodiment, the lower limit of the charging rate is referred to. Can be extracted from the technical manual of the target battery.

[0094] U3. When the charging control type is charging safety margin and charging rate, and As an adjustment indicator value.

[0095] The embodiment of the present invention collects the charging parameters of the battery pack and verifies the charging status and performs charging control analysis in combination with the cumulative charging tracking log of the battery pack, thereby ensuring that the battery is charged in the optimal state and avoiding overcharging or over-discharging, thereby extending the service life of the battery and improving its performance. At the same time, it also ensures the safety and controllability of the charging process, thereby further improving the management effect of the charging process.

[0096] The above contents are merely examples and explanations of the concept of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the present invention, they shall all fall within the protection scope of the present invention.

Claims

1. A method for dynamic control of a lithium battery energy storage system, characterized in that: include: S1. Importing charging settings: recording the current charging battery pack as the target battery pack, importing the initial state of charge, rated capacity and charging setting parameters of the target battery pack, wherein the charging setting parameters include setting the charging rate and setting the charging safety margin; S2. Charging parameter collection and storage: collect the current cumulative charging time and charging parameters of the target battery pack and store them in the charging information library; S3, charging status verification: extract the cumulative charging tracking log of the target battery pack from the charging information database, and verify the charging status based on it. If the verification result is safe, continue to execute the charging instruction according to the charging setting parameters, otherwise execute step S4; S4, charging control analysis: confirming the charging control type of the target battery pack and confirming the adjustment index value, wherein the charging control type is one or more of the charging safety margin and the charging rate; S5, charging control execution: feeding back the charging control type and adjustment index value of the target battery group to the charging control terminal of the target battery group, and performing charging control on the target battery group; The charging status verification includes: Extracting the charging temperature of each battery cell at each charging time point from the charging parameters; Traverse the charging temperature of each battery cell at each charging time point, extract the charging time point at which the highest temperature first appears for each battery cell, and record it as the charging temperature peak time point; The interval between the charging temperature peak time point and the first charging time point is taken as the temperature rise time, and the temperature rise state consistency of the target battery pack is calculated based on this, which is recorded as ; Extracting the current of each battery cell at each charging time point from the charging parameters, and calculating the state of charge of each battery cell at each charging time point by a coulomb counting method; With the charging time point as the horizontal coordinate and the state of charge as the vertical coordinate, the state of charge characteristic curve of each battery cell is constructed. Based on the state of charge characteristic curve of each battery cell, the state of charge conformity of the target battery pack is calculated, which is recorded as ; Extract the voltage of each battery cell at each charging time point from the charging parameters, and calculate the resistance of each battery cell at each charging time point , Indicates the battery cell number, , Indicates the charging time point number, , and then calculate the resistance state matching degree of the target battery pack, recorded as ; set up , and is the value of each verification indicator. If all verification indicator values ​​are greater than or equal to 0, safety is taken as the verification result. If there is a verification indicator value less than 0, unsafe is taken as the verification result. The determining the charging control type of the target battery pack includes: Traverse the temperature rise state of the target battery pack , Charge state consistency The consistency with the resistance state ; like Established and and All are greater than or equal to 0, and the charging safety margin is used as the charging control type of the target battery group; like and Established or and Established, taking charging rate as the charging control type of the target battery pack; like , and All less than 0 or and Or and Established, taking charging safety margin and charging rate as the charging control type of the target battery pack; The confirmation and adjustment of the index value includes: When the charging control type is charging safety margin, the setting charging safety margin is recorded as , calculate and adjust the charging safety margin , , is the upper limit of the charging safety margin. As an adjustment indicator value; When the charging control type is charging rate, the set charging rate is recorded as , calculate and adjust the charging rate , , To set the reference charging rate lower limit, As an adjustment indicator value; When the charging control type is charging safety margin and charging rate, and As an adjustment indicator value.

2. A method for dynamic control of a lithium battery energy storage system according to claim 1, characterized in that: The statistical target battery pack temperature rise state consistency includes: The variance of the temperature rise time of each battery cell is calculated, and the calculation result is used as the temperature rise difference, which is recorded as ; The temperature rise time of each battery cell is compared with the preset reference temperature rise time interval of the target battery group. If the temperature rise time of a battery cell is within the reference temperature rise time interval, the battery cell is recorded as a normal temperature rise cell. Count the number of cells with normal temperature rise and compare it with the number of battery cells. The ratio is taken as the temperature rise compliance ratio and recorded as ; Statistical consistency of temperature rise status of target battery pack , , is the set allowable battery cell temperature rise difference, To set the reference temperature rise compliance ratio.

3. A method for dynamic control of a lithium battery energy storage system according to claim 1, characterized in that: The calculating the charge state consistency of the target battery pack includes: Extracting a reference state-of-charge characteristic curve of the target battery pack from the charging information database and recording it as a reference curve; The state-of-charge characteristic curve of each battery cell is overlapped and compared with the reference curve to obtain the overlap curve length of each battery cell; The length of the overlap curve of each battery cell is compared with the length of the state of charge characteristic curve of each battery cell, and the ratio is recorded as the overlap curve ratio. The overlap curve ratio of each battery cell is recorded as ; A curve segment under the current accumulated charging time is selected from the reference curve and recorded as a reference curve segment; The slope of the state of charge characteristic curve is extracted as the state of charge change rate of each battery cell and recorded as , and at the same time extract the slope of the reference curve segment as the reference charge state change rate ; The first evaluation variable and the second evaluation variable of each battery cell are set as and ; Count the charge state consistency of each battery cell , , , and To set the conditions, express and Established or and Established, express and Established, express and Established; The minimum value is selected from the state of charge consistency of each battery unit as the state of charge consistency of the target battery pack.

4. A method for dynamic control of a lithium battery energy storage system according to claim 3, characterized in that: The step of setting the first evaluation variable and the second evaluation variable of each battery cell comprises: set up The first evaluation variable for each battery cell , is the preset reference coincidence curve ratio; set up The second evaluation variable for each battery cell , is the preset state of charge change rate difference.

5. A method for dynamic control of a lithium battery energy storage system according to claim 1, characterized in that: The calculating the resistance state consistency of the target battery pack includes: Extract the unit change of the target battery internal resistance with temperature from the charging information database, recorded as , and the charging temperature of each battery cell at each charging time point is recorded as ; The corrected resistance value of each battery cell at each charging time point is counted and recorded as , , is the set reference temperature; Set the reference resistance value of each battery cell at each charging time point, denoted as ; Comparing the corrected resistance value of each battery cell at each charging time point with the reference resistance value; If the corrected resistance value of a battery cell at a certain charging time point is less than or equal to the reference resistance value, then the charging time point is recorded as a resistance matching time point; The number of resistance matching time points of each battery cell is counted and compared with the number of charging time points. The ratio is taken as the resistance matching degree of each battery cell, which is recorded as ,Will As the resistance state match of the target battery pack, To set the reference resistance fit.

6. A method for dynamic control of a lithium battery energy storage system according to claim 5, characterized in that: The step of setting the reference resistance value of each battery cell at each charging time point includes: Extract the cumulative number of charge and discharge cycles from the cumulative charge tracking log of the target battery pack and record it as ; Extracting the temperature, current and voltage at each charging time point during each cumulative charging from the cumulative charging tracking log; according to , and The calculation method is to calculate the verification index values ​​of each cumulative charge in turn, and set the health deviation trend factor of the target battery pack. ; Extract the reference resistance of the target battery pack from the charging information database, denoted as , count the reference resistance value of each battery cell at each charging time point , , is the supplementary resistance value corresponding to the set unit health deviation trend factor, The temperature reference reduction ratio is set corresponding to the set unit health deviation trend factor.

7. A method for dynamic control of a lithium battery energy storage system according to claim 6, characterized in that: The setting of the health deviation trend factor includes: The accumulated charging with a verification index value less than 0 is recorded as deviation charging, and the verification index value less than 0 is recorded as deviation index value; Count the number of deviation charging times and compare it with the cumulative number of charging times. The ratio is recorded as the deviation charging ratio. ; Count the number of deviation index values ​​corresponding to each deviation charging, and compare it with the number of verification index values, and record the ratio as the deviation index ratio; The deviation index ratio corresponding to each deviation charging is averaged to obtain the deviation charging index ratio ; Setting the health deviation trend factor , , , and The reference charge and discharge cycle number, deviation charge ratio and deviation charge index ratio are set respectively. is a natural constant.

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