A battery in-situ lithium extraction and battery capacity restoration system and method

Abstract

The application relates to a battery in-situ lithium precipitation detection and battery capacity repair system and method, in particular to the technical field of battery detection, which comprises an acquisition module used for carrying out aging test on a fresh battery to acquire standard threshold values of various parameters of the target battery; a test module used for testing the target battery to obtain test data; an analysis module used for analyzing the target battery according to the standard threshold values and the test data and marking the target battery according to the lithium precipitation risk; a judgment module used for judging the battery state according to the marking of the target battery; a processing module used for processing the target battery according to the battery state to determine whether the target battery is an aging battery; and a repair module used for repairing the aging battery. The battery in-situ lithium precipitation detection and battery capacity repair system and method provided by the application can detect the lithium precipitation state of the power battery without disassembling the storage battery, partially eliminates the lithium precipitation on the surface of the battery, reduces the lithium precipitation detection cost of the battery, and improves the detection efficiency.

Description

Technical Field

[0001] This invention relates to the field of battery testing technology, and in particular to a battery in-situ lithium plating detection and battery capacity repair system and method. Background Technology

[0002] Lithium plating is prone to occur in batteries after frequent charge-discharge use. Lithium plating can negatively impact battery safety characteristics, making its detection and assessment crucial. Currently, common lithium plating methods include inserting a third electrode, advanced analytical characterization techniques, and visual inspection via disassembly. However, a current problem is that most common methods require damaging the battery to observe the lithium plating.

[0003] Chinese Patent Publication No. CN202210022682.0 discloses a method for detecting lithium plating in batteries, including acquiring voltage and current signals of the battery under test during a preset time period during discharge. A first target feature parameter is determined based on the signals, which characterizes the intrinsic mode functions (EMFs) in a stable state within the voltage signal. Based on the first target feature parameter and the current signal, it is determined whether lithium plating has occurred in the battery under test. This method requires determining multiple EMFs and their corresponding center frequencies using a variational mode decomposition algorithm. However, this approach suffers from high cost, low efficiency, and limited practicality in lithium plating detection. Summary of the Invention

[0004] Therefore, the present invention provides a battery in-situ lithium plating detection and battery capacity repair system and method to overcome the problems of high cost, low detection efficiency and low practicality of existing battery lithium plating detection technologies.

[0005] To achieve the above objectives, in one aspect, the present invention provides a battery in-situ lithium plating detection and battery capacity repair system, comprising,

[0006] The acquisition module is used to perform aging tests on fresh batteries to obtain standard thresholds for various parameters of the target battery;

[0007] The testing module is used to test the target battery and obtain test data. The testing module includes a multi-stage constant voltage discharge unit, a low-current charge-discharge unit, and a low-temperature AC impedance unit. The multi-stage constant voltage discharge unit is used to perform multi-stage constant voltage discharge tests on the target battery to obtain the capacity D3 of the first step discharge, the capacity D4 of the second step discharge, and the nominal capacity D5 of the target battery. The low-current charge-discharge unit is used to perform low-current charge-discharge tests on the target battery to obtain the discharge capacity D6 and the discharge voltage U1 of the target battery. The low-temperature AC impedance unit is used to perform low-temperature AC impedance tests on the target battery to obtain the ohmic impedance of the target battery and the sum of the solid electrolyte impedance and the solid electrolyte impedance.

[0008] The analysis module is used to analyze the target battery based on the standard threshold obtained by the acquisition module and the test data obtained by the test module. This includes analyzing the lithium plating risk of the target battery based on the capacity D3 of the first step discharge, analyzing the lithium plating risk of the target battery based on the differential capacity curve of the target battery, and analyzing the lithium plating risk of the target battery based on the ohmic impedance of the target battery, so as to determine the lithium plating risk of the target battery. The analysis module marks the target battery for different analysis processes, marking it as positive when there is a lithium plating risk and marking it as negative when there is no lithium plating risk.

[0009] The judgment module is used to determine the battery status based on the markings of the target battery in the battery analysis results. The battery status includes A-level risk, B-level risk, and no lithium plating risk.

[0010] The processing module is used to process the target battery according to the battery status, and to determine whether the target battery is an aged battery and whether it needs capacity repair.

[0011] The repair module is used to repair aging batteries.

[0012] Furthermore, the acquisition module performs aging tests on the fresh battery and uses the test results as standard thresholds for the corresponding parameters of the target battery. The aging tests include multi-stage constant voltage discharge tests, low-current charge-discharge tests, and low-temperature AC impedance tests.

[0013] During multi-stage constant voltage discharge testing, the acquisition module charges the fresh battery with constant current to a preset first voltage V1 under a preset first current C1, and then charges it with constant voltage to a preset second current C2 to obtain the capacity D1 of the standard first step discharge. After a preset first time interval ΔT1, the fresh battery is discharged with constant current to a preset second voltage V2 under a preset second current C2, and then discharged with constant voltage to a preset third current C3 to obtain the capacity D2 of the standard second step discharge. The first threshold is set as E0, and the nominal capacity of the battery is D. E0 = D2 / D. The nominal capacity of the battery is D, which refers to the discharge capacity of the battery when discharged at 0.2C, where C is the C-rate of the battery.

[0014] During the low-current charge-discharge test, the acquisition module charges the fresh battery with constant current to a preset third voltage V3 under a preset third current C3, then charges it with constant voltage to a preset fourth current C4, and sets it for a preset second time interval ΔT2. Under a preset fifth current C5, the battery discharges with constant current to a preset fourth voltage V4, and sets it for a preset second time interval ΔT2. Under a preset fifth current C5, the battery is charged with constant current to a preset fifth voltage V5, and then set for a preset second time interval ΔT2. The standard discharge capacity D0 and standard discharge voltage U0 are obtained. Incremental capacity analysis is performed based on the standard discharge capacity D0 and standard discharge voltage U0, and the dQ / dV-V differential capacity curve is plotted to obtain the standard differential capacity curve.

[0015] During the low-temperature AC impedance test, the acquisition module charges the fresh battery to a preset power battery charge SOC1 under preset first temperature T1 and preset sixth current C6 conditions. After being left to stand at a preset second temperature T2 for a preset third time interval ΔT3, the AC impedance test is performed, the real part-imaginary part curve of the AC impedance is plotted, and the standard ohmic impedance and the sum of the standard solid electrolyte impedance and the solid electrolyte impedance are obtained by fitting a second-order RC circuit using Z-view software. The standard ohmic impedance is set as F0, and the sum of the standard solid electrolyte impedance and the solid electrolyte impedance is set as G0.

[0016] Furthermore, when testing the target battery, the multi-stage constant voltage discharge unit charges the target battery with a constant current to a preset first voltage V1 under a preset first current C1, and then charges it with a constant voltage to a preset second current C2 to obtain the capacity D3 of the first step discharge of the target battery. After being left to stand for a preset first time interval ΔT1, it discharges with a constant current to a preset second voltage V2 under a preset second current C2, and then discharges it with a constant voltage to a preset third current C3 to obtain the capacity D4 of the second step discharge of the target battery.

[0017] The low-current charging and discharging unit charges the target battery with constant current to a preset third voltage V3 under a preset third current C3, then charges it with constant voltage to a preset fourth current C4, and sets it for a preset second time interval ΔT2. Then, it discharges the target battery with constant current to a preset fourth voltage V4 under a preset fifth current C5, sets it for a preset second time interval ΔT2, charges the target battery with constant current to a preset fifth voltage V5 under a preset fifth current C5, and sets it for a preset second time interval ΔT2. The discharge capacity D6 and discharge voltage U1 of the target battery are obtained. Incremental capacity analysis is performed based on the discharge capacity D6 and discharge voltage U1 of the target battery, and the dQ / dV-V differential capacity curve is plotted to obtain the differential capacity curve of the target battery.

[0018] The low-temperature AC impedance unit charges the target battery to SOC1 under a preset first temperature T1 and a preset sixth current C6. After being left to stand at a preset second temperature T2 for a preset third time interval ΔT3, an AC impedance test is performed. The real-imaginary part curve of the AC impedance is plotted, and a second-order RC circuit is used to fit the target battery to obtain the ohmic impedance and the sum of the solid electrolyte impedance and the solid electrolyte impedance. The ohmic impedance of the target battery is set as F1, and the sum of the solid electrolyte impedance and the solid electrolyte impedance is set as G1.

[0019] Furthermore, the analysis module compares the capacity D3 of the first step discharge of the target battery with the preset discharge capacity C0, and analyzes the lithium plating risk of the target battery based on the comparison results.

[0020] When D3 < C0, the target battery determination value is set to E1, and E1 = D4 / D5. The analysis module compares E1 with E0 and analyzes the lithium plating risk of the target battery based on the comparison result.

[0021] If E1≥E0, the analysis module determines that the target battery has a risk of lithium plating and marks the target battery as positive;

[0022] If E1 < E0, the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative;

[0023] When D3≥C0, the analysis module retests the target battery to obtain the capacity D3' of the first step discharge of the corrected target battery, where,

[0024] When D3'≥C0, the analysis module discards the test data of the multi-stage constant voltage discharge unit of the target battery;

[0025] When D3' < C0, the analysis module obtains the capacity D4' of the second step discharge of the target battery, sets the target battery determination value to E1', and E1' = D4' / D5. The analysis module compares E1' with E0 and analyzes the lithium plating risk of the target battery based on the comparison results.

[0026] If E1'≥E0, the analysis module determines that the target battery has a risk of lithium plating and marks the target battery as positive;

[0027] If E1' < E0, the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative.

[0028] Furthermore, the analysis module compares the peaks and valleys of the target battery's differential capacity curve obtained from the low-current charge-discharge unit test with the standard differential capacity curve at the preset sixth voltage V6 and preset seventh voltage V7, and determines the lithium plating risk of the target battery based on the comparison results.

[0029] When the peak and valley of the differential capacity curve of the target battery with the preset sixth voltage V6 shifts to the left relative to the peak and valley of the standard differential capacity curve, and the peak and valley of the differential capacity curve of the target battery with the preset seventh voltage V7 shifts to the right relative to the peak and valley of the standard differential capacity curve, the analysis module determines that data analysis of the target battery is required.

[0030] When the peak and valley of the differential capacity curve of the target battery with the preset sixth voltage V6 shifts to the left relative to the peak and valley of the standard differential capacity curve, and the peak and valley of the differential capacity curve of the target battery with the preset seventh voltage V7 shifts to the left relative to the peak and valley of the standard differential capacity curve, the analysis module determines that no data analysis of the target battery is required.

[0031] When the peaks and valleys of the differential capacity curve of the target battery with the preset sixth voltage V6 shift to the right relative to the peaks and valleys of the standard differential capacity curve, and the peaks and valleys of the differential capacity curve of the target battery with the preset seventh voltage V7 shift to the right relative to the peaks and valleys of the standard differential capacity curve, the analysis module determines that no data analysis of the target battery is required.

[0032] When the peak and valley of the differential capacity curve of the target battery with the preset sixth voltage V6 shifts to the right relative to the peak and valley of the standard differential capacity curve, and the peak and valley of the differential capacity curve of the target battery with the preset seventh voltage V7 shifts to the left relative to the peak and valley of the standard differential capacity curve, the analysis module determines that no data analysis of the target battery is required.

[0033] When data analysis of the target battery is required, the analysis module acquires the incremental capacity analysis threshold H0 of the standard differential capacity curve at the preset sixth voltage V6, the incremental capacity analysis threshold H1 of the differential capacity curve of the target battery at the preset sixth voltage V6, the incremental capacity analysis threshold H2 of the differential capacity curve of the target battery at the preset seventh voltage V7, and the incremental capacity analysis threshold H0' of the differential capacity curve of the target battery at the preset seventh voltage V7. The analysis module compares H0, H1, H0', and H2, and determines the lithium plating risk of the target battery based on the comparison results.

[0034] When H1 < H0, and H1 > H2, H2 < H0', the analysis module determines that the target battery has a risk of lithium plating and marks the target battery as positive;

[0035] When H1 < H0, and H1 > H2, and H2 ≥ H0', the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative;

[0036] When H1 < H0, and H1 ≤ H2, H2 < H0', the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative;

[0037] When H1≥H0, and H1>H2, H2≥H0', the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative;

[0038] When H1≥H0, and H1≤H2, H2≥H0', the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative;

[0039] When H1≥H0, and H1≤H2, H2<H0', the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative.

[0040] Furthermore, the analysis module compares the ohmic impedance of the target battery with the standard ohmic impedance, and the sum of the solid electrolyte impedance of the target battery and the standard solid electrolyte impedance with the standard solid electrolyte impedance, based on the test results of the low-temperature AC impedance unit. Based on the comparison results, it assesses the lithium plating risk of the target battery, setting the standard ohmic impedance as F0, the sum of the standard solid electrolyte impedance and the solid electrolyte impedance as G0, the ohmic impedance of the target battery as F1, and the sum of the solid electrolyte impedance of the target battery and the solid electrolyte impedance as G1.

[0041] When F1 < F0 and G1 > G0, the analysis module determines that the target battery has a risk of lithium plating and marks the target battery as positive.

[0042] When F1 < F0 and G1 ≤ G0, the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative.

[0043] When F1≥F0 and G1>G0, the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative;

[0044] When F1≥F0 and G1≤G0, the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative.

[0045] Furthermore, the judgment module determines the battery status based on the battery analysis results, wherein,

[0046] When the target battery is marked as positive in the multi-stage constant voltage discharge analysis, positive in the low current charge-discharge analysis, and positive in the low temperature AC impedance analysis, the judgment module determines that the lithium plating risk of the target battery is Class A risk.

[0047] When the target battery is marked as positive in the multi-stage constant voltage discharge analysis, negative in the low current charge-discharge analysis, and positive in the low temperature AC impedance analysis, the judgment module determines that the lithium plating risk of the target battery is Grade A.

[0048] When the target battery is marked as positive in the multi-stage constant voltage discharge analysis, positive in the low current charge-discharge analysis, and negative in the low temperature AC impedance analysis, the judgment module determines that the lithium plating risk of the target battery is Grade A.

[0049] When the target battery is marked as negative in the multi-stage constant voltage discharge analysis, positive in the low current charge-discharge analysis, and positive in the low temperature AC impedance analysis, the judgment module determines that the lithium plating risk of the target battery is grade B.

[0050] When the target battery is marked as positive in the multi-stage constant voltage discharge analysis, negative in the low current charge-discharge analysis, and negative in the low temperature AC impedance analysis, the judgment module determines that the lithium plating risk of the target battery is grade B.

[0051] When the target battery is marked as negative in the multi-stage constant voltage discharge analysis, positive in the low current charge-discharge analysis, and negative in the low temperature AC impedance analysis, the judgment module determines that the lithium plating risk of the target battery is grade B.

[0052] When the target battery is marked as negative in the multi-stage constant voltage discharge analysis, negative in the low current charge-discharge analysis, and positive in the low temperature AC impedance analysis, the judgment module determines that the lithium plating risk of the target battery is grade B.

[0053] When the target battery is marked as negative in the multi-stage constant voltage discharge analysis, negative in the low current charge-discharge analysis, and negative in the low temperature AC impedance analysis, the judgment module determines that the target battery does not have a risk of lithium plating.

[0054] Furthermore, the processing module processes the target battery according to its battery state, wherein...

[0055] When the target battery is classified as a Class A risk, the processing module determines that the target battery is an aged battery and requires capacity repair.

[0056] When the target battery is classified as a Class B risk, the processing module selects the test data marked as positive for the target battery, compares each test data with each standard threshold, and judges the target battery based on the comparison results. If there is a test data value greater than twice the standard threshold, the processing module determines that the battery is an aged battery and needs to be repaired. If there is no test data value greater than twice the standard threshold, the processing module determines that the battery is not an aged battery and can be restored during the next maintenance.

[0057] When the target battery does not have the risk of lithium plating, the processing module determines that the target battery is an aged battery and does not require capacity repair.

[0058] Furthermore, the repair module discharges the target battery that needs capacity repair with a preset first repair current C1' at a constant current. When the discharge reaches the cutoff voltage of the preset repair voltage V', the target battery is discharged at a constant voltage to the preset second repair current C2'.

[0059] On the other hand, the present invention also provides a method for in-situ lithium plating detection and battery capacity repair, comprising,

[0060] Step S1: Use the acquisition module to perform an aging test on the fresh battery to obtain the standard threshold values ​​for each parameter of the target battery.

[0061] Step S2: Test data is obtained by testing the target battery through the test module. During the test, the target battery is subjected to multi-stage constant voltage discharge test through the multi-stage constant voltage discharge unit to obtain the capacity D3 of the first step discharge, the capacity D4 of the second step discharge, and the nominal capacity D5 of the target battery. The target battery is subjected to small current charge and discharge test through the small current charge and discharge unit to obtain the discharge capacity D6 and the discharge voltage U1 of the target battery. The target battery is subjected to low temperature AC impedance test through the low temperature AC impedance unit.

[0062] Step S3: The target battery is analyzed by the analysis module according to the standard threshold and test data, and the lithium plating risk of the target battery is judged based on the analysis results. The battery is then marked according to the risk judgment results.

[0063] Step S4: The judgment module determines the battery status based on the target battery's markings.

[0064] Step S5: The processing module determines whether the target battery is an aged battery based on the battery status.

[0065] Step S6: Repair the aging battery using the repair module.

[0066] Compared with existing technologies, the beneficial effects of this invention are as follows: the system acquires standard threshold values ​​for various parameters of the target battery by performing aging tests on fresh batteries through an acquisition module, thereby obtaining various parameters for normal battery operation, ensuring data accuracy, and improving the efficiency of lithium plating detection. These parameters include the capacity of the first step discharge, the capacity of the second step discharge, the dQ / dV-V differential capacity curve, ohmic impedance, and the sum of the solid electrolyte impedance and solid electrolyte impedance. The testing module includes a multi-stage constant voltage discharge unit, a low-current charge-discharge unit, and a low-temperature AC impedance unit to test the target battery, obtaining various test data, thereby acquiring the actual state of the target battery, ensuring data reliability, and further improving the efficiency of lithium plating detection. After obtaining the test data, the analysis module analyzes the standard threshold and the test data, marking batteries with lithium plating risk as positive and batteries without lithium plating risk as negative, thus initially determining the lithium plating risk of the target battery based on the test data to improve the lithium plating detection efficiency. The judgment module judges the battery status based on the marking of the target battery in the battery analysis results, further determining the battery lithium plating risk, thereby improving the lithium plating detection efficiency. The processing module processes the target battery according to the battery status, determining whether the target battery is an aged battery and whether it needs capacity repair, thereby improving the lithium plating detection efficiency. The repair module is used to repair the target battery that needs repair, thereby restoring the battery's working state and partially eliminating lithium plating on the battery surface.

[0067] In particular, the acquisition module performs multi-stage constant voltage discharge test, low current charge-discharge test, and low temperature AC impedance test to obtain the capacity D1 of the first standard step discharge, the capacity D2 of the second standard step discharge, the first threshold E0, the standard discharge capacity D0, the standard discharge voltage U0, the standard differential capacity curve, the standard ohmic impedance, and the sum of the standard solid electrolyte impedance and the solid electrolyte impedance, thereby clarifying each standard threshold and determining the data for normal operation of the target battery, thus improving the efficiency of lithium plating detection.

[0068] In particular, the multi-stage constant voltage discharge unit tests the target battery to obtain the capacity D3 of the first step discharge and the capacity D4 of the second step discharge. The low current charge-discharge unit tests the target battery to obtain the discharge capacity D6, the discharge voltage U1, and the differential capacity curve. The low temperature AC impedance unit obtains the ohmic impedance of the target battery and the sum of the solid electrolyte impedance and the solid electrolyte impedance, thereby obtaining the actual state of the target battery, ensuring the validity of the data, and improving the lithium plating detection efficiency of the battery.

[0069] In particular, when analyzing the test data obtained from the multi-stage constant voltage discharge unit test, if the capacity D3 of the first step discharge of the target battery is greater than or equal to C0, the analysis module retests the target battery to obtain a corrected capacity D3' for the first step discharge of the target battery, thereby ensuring the validity of the test data and improving the lithium plating detection efficiency of the battery. If the capacity D3 of the first step discharge of the target battery is less than C0, the analysis module compares the target battery judgment value E1 with the first threshold E0, and obtains the lithium plating risk of the target battery based on the comparison result of E1 and E0, thereby initially determining whether the target battery is normal and improving the lithium plating detection efficiency of the battery. For lithium detection efficiency, after obtaining the capacity D3' of the first step discharge of the target battery, the analysis module analyzes the target battery. When the capacity D3' of the first step discharge of the target battery is greater than or equal to C0, the analysis module discards the test data of the multi-stage constant voltage discharge unit of the target battery to ensure the validity of the test data. When the capacity D3' of the first step discharge of the target battery is less than C0, the analysis module compares the judgment value E1' of the target battery with the first threshold E0. Based on the comparison result, the lithium plating risk of the target battery is obtained, thereby initially determining whether the target battery is normal and improving the lithium plating detection efficiency of the battery.

[0070] In particular, the analysis module compares the peaks and valleys of the differential capacity curve of the target battery in the low-current charge-discharge unit with the peaks and valleys of the standard differential capacity curve at the preset sixth voltage V6 and preset seventh voltage V7. When the peaks and valleys of the differential capacity curve of the target battery at the preset sixth voltage V6 shift to the left relative to the peaks and valleys of the standard differential capacity curve, and the peaks and valleys of the differential capacity curve of the target battery at the preset seventh voltage V7 shift to the right relative to the peaks and valleys of the standard differential capacity curve, the analysis module compares the incremental capacity analysis threshold H0 of the standard differential capacity curve at the preset sixth voltage V6, the incremental capacity analysis threshold H1 of the differential capacity curve of the target battery at the preset sixth voltage V6, the incremental capacity analysis threshold H2 of the differential capacity curve of the target battery at the preset seventh voltage V7, and the incremental capacity analysis threshold H0' of the differential capacity curve of the target battery at the preset seventh voltage V7, and marks the target battery according to the comparison results, thereby further determining that the target battery has the risk of lithium plating and improving the lithium plating detection efficiency of the battery.

[0071] In particular, the analysis module compares the ohmic impedance of the target battery with the standard ohmic impedance, and the sum of the solid electrolyte impedance of the target battery and the standard solid electrolyte impedance with the standard solid electrolyte impedance, based on the test results of the low-temperature AC impedance unit. Based on the comparison results, it further determines that the target battery has a risk of lithium plating, marks the target battery, and thus further determines that the target battery has a risk of lithium plating, thereby improving the lithium plating detection efficiency of the battery.

[0072] In particular, the judgment module determines the battery status based on the target battery's markings in the battery analysis results, thereby further determining the level of lithium plating risk and improving the lithium plating detection efficiency of the battery. Attached Figure Description

[0073] Figure 1 This is a schematic diagram of the battery in-situ lithium plating detection and battery capacity repair system in this embodiment;

[0074] Figure 2 This is a schematic diagram of the test module in the battery in-situ lithium plating detection and battery capacity repair system of this embodiment;

[0075] Figure 3 This is a flowchart illustrating the in-situ lithium plating detection and battery capacity repair method in this embodiment. Detailed Implementation

[0076] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0077] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0078] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0079] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0080] Please see Figure 1 As shown, this is the battery in-situ lithium plating detection and battery capacity repair system of this embodiment. The system includes,

[0081] The acquisition module is used to perform aging tests on fresh batteries to obtain standard thresholds for various parameters of the target battery;

[0082] The test module is used to test the target battery and obtain test data.

[0083] Please see Figure 2 The diagram shows the structure of the test module in the battery in-situ lithium plating detection and battery capacity repair system of this embodiment. The test module includes a multi-stage constant voltage discharge unit, a small current charge-discharge unit, and a low-temperature AC impedance unit. The multi-stage constant voltage discharge unit is used to perform multi-stage constant voltage discharge tests on the target battery to obtain the capacity D3 of the first step discharge, the capacity D4 of the second step discharge, and the nominal capacity D5 of the target battery. The small current charge-discharge unit is used to perform small current charge-discharge tests on the target battery to obtain the discharge capacity D6 and the discharge voltage U1 of the target battery. The low-temperature AC impedance unit is used to perform low-temperature AC impedance tests on the target battery to obtain the ohmic impedance of the target battery and the sum of the solid electrolyte impedance and the solid electrolyte impedance.

[0084] Please continue reading. Figure 1 As shown, the system described in this embodiment also includes,

[0085] The analysis module is used to analyze the target battery based on the standard threshold obtained by the acquisition module and the test data obtained by the test module. This includes analyzing the lithium plating risk of the target battery based on the capacity D3 of the first step discharge, analyzing the lithium plating risk of the target battery based on the differential capacity curve of the target battery, and analyzing the lithium plating risk of the target battery based on the ohmic impedance of the target battery, so as to determine the lithium plating risk of the target battery. The analysis module marks the target battery for different analysis processes, marking it as positive when there is a lithium plating risk and marking it as negative when there is no lithium plating risk.

[0086] The judgment module is used to determine the battery status based on the markings of the target battery in the battery analysis results. The battery status includes A-level risk, B-level risk, and no lithium plating risk.

[0087] The processing module is used to process the target battery according to the battery status, and to determine whether the target battery is an aged battery and whether it needs capacity repair.

[0088] The repair module is used to repair aging batteries.

[0089] Specifically, the system acquires standard threshold values ​​for various parameters of the target battery by performing aging tests on fresh batteries through an acquisition module. This allows for the determination of parameters necessary for normal battery operation, ensuring data accuracy and improving lithium plating detection efficiency. These parameters include the capacity of the first step discharge, the capacity of the second step discharge, the dQ / dV-V differential capacity curve, ohmic impedance, and the sum of the solid electrolyte impedance and solid electrolyte impedance. The testing module utilizes a multi-stage constant voltage discharge unit, a low-current charge-discharge unit, and a low-temperature AC impedance unit to test the target battery, obtaining various test data and thus assessing its actual state. This ensures data reliability and further improves lithium plating detection efficiency. The analysis module then analyzes the standard thresholds and test data, marking batteries with lithium plating risk as positive and those without as negative, thus initially determining the lithium plating risk of the target battery based on the test data to improve the lithium plating detection efficiency. The judgment module determines the battery status based on the markings of the target battery in the battery analysis results, further determining the lithium plating risk, thereby improving the lithium plating detection efficiency. The processing module processes the target battery according to its status, determining whether it is an aged battery and whether it needs capacity repair, thereby improving the lithium plating detection efficiency. The repair module repairs the target battery that needs repair, thereby restoring the battery's working state and partially eliminating lithium plating on the battery surface.

[0090] Specifically, the acquisition module performs aging tests on fresh batteries and uses the test results as standard thresholds for the corresponding parameters of the target battery. The aging tests include multi-stage constant voltage discharge tests, low-current charge-discharge tests, and low-temperature AC impedance tests. The fresh batteries are unused batteries of the same model as the target battery being tested.

[0091] During the multi-stage constant voltage discharge test, the acquisition module charges the fresh battery with a constant current to a preset first voltage V1 under a preset first current C1. In this embodiment, C1 = 1 / 3C and V1 = 4.3V. Then, it charges the battery with a constant voltage to a preset second current C2. In this embodiment, C2 = 0.02C, thus obtaining the capacity D1 of the standard first step discharge. After a preset first time interval ΔT1, the fresh battery is discharged with a constant current to a preset second voltage V2 under a preset second current C2. Then, it is discharged with a constant voltage to a preset third current C3, thus obtaining the capacity D2 of the standard second step discharge. In this embodiment, T1 = 30min, V2 = 2.8V, and C3 = 0.02C. The first threshold is set as E0, and the nominal battery capacity is D. E0 = D2 / D. The nominal battery capacity D refers to the discharge capacity of the battery at 0.2C discharge, where C is the C-rate of the battery.

[0092] During the low-current charge-discharge test, the acquisition module charges the fresh battery with constant current to a preset third voltage V3 under a preset third current C3, then charges it with constant voltage to a preset fourth current C4, and sets it for a preset second time interval ΔT2. Then, it discharges the battery with constant current to a preset fourth voltage V4 under a preset fifth current C5, sets it for a preset second time interval ΔT2, and then charges it with constant current to a preset fifth voltage V5 under a preset fifth current C5, and sets it for a preset second time interval ΔT2. This yields the standard discharge capacity D0 and standard discharge voltage U0. Incremental capacity analysis is performed based on the standard discharge capacity D0 and standard discharge voltage U0, and a dQ / dV-V differential capacity curve is plotted to obtain the standard differential capacity curve. In this embodiment, V3=4.3V, C4=0.02C, ΔT2=30min, C5=0.05C, V4=2.8Vc, and V5=4.3V.

[0093] During the low-temperature AC impedance test, the acquisition module charges the fresh battery to a preset power battery charge SOC1 under preset first temperature T1 and preset sixth current C6 conditions. It then places the battery at a preset second temperature T2 for a preset third time interval ΔT3, performs the AC impedance test, plots the real-imaginary part curve of the AC impedance, and uses Z-view software to fit a second-order RC circuit to obtain the standard ohmic impedance and the sum of the standard solid electrolyte impedance and the solid electrolyte impedance. In this embodiment, T1=25℃, C6=1 / 3C, SOC1=97%, T2=-20℃, ΔT3=12h, and the standard ohmic impedance is set as F0, and the sum of the standard solid electrolyte impedance and the solid electrolyte impedance is set as G0.

[0094] Specifically, in this embodiment, when the standard threshold of a certain parameter cannot be directly obtained through a single aging test, those skilled in the art can obtain several test values ​​of the parameter by performing aging tests on multiple different fresh batteries, and establish a parameter library for the measured test values ​​of the parameter. Based on the unified learning method, the data is analyzed to find outliers as the standard threshold. Those skilled in the art can also set other methods to obtain the standard threshold of the parameter, and this embodiment does not make specific limitations.

[0095] Specifically, the acquisition module performs multi-stage constant voltage discharge testing, low-current charge-discharge testing, and low-temperature AC impedance testing to obtain the standard first-stage discharge capacity D1, standard second-stage discharge capacity D2, first threshold E0, standard discharge capacity D0, standard discharge voltage U0, standard differential capacity curve, standard ohmic impedance, and the sum of standard solid electrolyte impedance and solid electrolyte impedance. This clarifies each standard threshold, determines the data for normal operation of the target battery, and thus improves the efficiency of lithium plating detection. It is understood that this embodiment does not specifically limit the method for determining lithium plating risk through standard thresholds. Those skilled in the art can also confirm this through large-sample statistical methods. If outliers exist in the data, their selection can be based on data from the same mileage or data from the same battery cell.

[0096] Specifically, when testing the target battery, the multi-stage constant voltage discharge unit charges the target battery with constant current to a preset first voltage V1 under a preset first current C1, and then charges it with constant voltage to a preset second current C2 to obtain the capacity D3 of the first step discharge of the target battery. After being left to stand for a preset first time interval ΔT1, it discharges with constant current to a preset second voltage V2 under a preset second current C2, and then discharges it with constant voltage to a preset third current C3 to obtain the capacity D4 of the second step discharge of the target battery.

[0097] The low-current charging and discharging unit charges the target battery with constant current to a preset third voltage V3 under a preset third current C3, then charges it with constant voltage to a preset fourth current C4, and sets it for a preset second time interval ΔT2. Then, it discharges the target battery with constant current to a preset fourth voltage V4 under a preset fifth current C5, sets it for a preset second time interval ΔT2, charges the target battery with constant current to a preset fifth voltage V5 under a preset fifth current C5, and sets it for a preset second time interval ΔT2. The discharge capacity D6 and discharge voltage U1 of the target battery are obtained. Incremental capacity analysis is performed based on the discharge capacity D6 and discharge voltage U1 of the target battery, and the dQ / dV-V differential capacity curve is plotted to obtain the differential capacity curve of the target battery.

[0098] The low-temperature AC impedance unit charges the target battery to SOC=97% under a preset first temperature T1 and a preset sixth current C6. After being left to stand at a preset second temperature T2 for a preset third time interval ΔT3, an AC impedance test is performed. The real-imaginary part curve of the AC impedance is plotted, and the ohmic impedance of the target battery and the sum of the solid electrolyte impedance and solid electrolyte impedance are obtained by fitting a second-order RC circuit using Z-view software. In this embodiment, C5=1 / 3C, the ohmic impedance of the target battery is set as F1, and the sum of the solid electrolyte impedance and solid electrolyte impedance is G1.

[0099] Specifically, the multi-stage constant voltage discharge unit tests the target battery to obtain the capacity D3 of the first step discharge and the capacity D4 of the second step discharge. The low-current charge-discharge unit tests the target battery to obtain the discharge capacity D6, the discharge voltage U1, and the differential capacity curve. The low-temperature AC impedance unit obtains the ohmic impedance and the sum of the solid electrolyte impedance and the solid electrolyte impedance of the target battery, thereby obtaining the actual state of the target battery, ensuring the validity of the data, and improving the lithium plating detection efficiency. The multi-stage constant voltage discharge test refers to the battery being discharged at a constant current from a fully charged state to the cutoff voltage. The battery is then discharged to a minimum current In using the cutoff voltage as a constant voltage. The cutoff current can have multiple values ​​to form a multi-stage discharge test. The low-current charge-discharge test refers to a process of fully charging – low-rate discharge – low-rate charging or fully charging – low-rate discharge, preferably the latter. The low-rate discharge process refers to low-current constant discharge to the lower cutoff voltage, and the low-rate charging process refers to low-current constant charging to the upper cutoff voltage. The low-temperature AC impedance test refers to three steps: adjusting the battery state at room temperature – low-temperature resting – AC impedance testing. The basic premise for the low-temperature AC impedance test is that a typical semi-circular curve of the real and imaginary parts of the AC impedance can be generated under specific low-temperature testing conditions. It is understood that this embodiment does not specifically limit the differential capacity curve of the target battery in the low-current charge-discharge unit. Those skilled in the art can freely set it according to actual needs, such as setting the differential capacity curve of the target battery in the low-current charge-discharge unit as a dV / dQ-Q curve.

[0100] Specifically, the analysis module compares the capacity D3 of the first step discharge of the target battery with the preset discharge capacity C0. In this embodiment, C0 = 2Ah. Based on the comparison results, the lithium plating risk of the target battery is analyzed.

[0101] When D3 < C0, the target battery determination value is set to E1, and E1 = D4 / D5. The analysis module compares E1 with E0 and analyzes the lithium plating risk of the target battery based on the comparison result.

[0102] If E1≥E0, the analysis module determines that the target battery has a risk of lithium plating and marks the target battery as positive;

[0103] If E1 < E0, the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative;

[0104] When D3≥C0, the analysis module retests the target battery to obtain the capacity D3' of the first step discharge of the corrected target battery, where,

[0105] When D3'≥C0, the analysis module discards the test data of the multi-stage constant voltage discharge unit of the target battery;

[0106] When D3' < C0, the analysis module obtains the capacity D4' of the second step discharge of the target battery, sets the target battery determination value to E1', and E1' = D4' / D5. The analysis module compares E1' with E0 and analyzes the lithium plating risk of the target battery based on the comparison results.

[0107] If E1'≥E0, the analysis module determines that the target battery has a risk of lithium plating and marks the target battery as positive;

[0108] If E1' < E0, the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative.

[0109] Specifically, when analyzing the test data obtained from the multi-stage constant voltage discharge unit test, if the capacity D3 of the first step discharge of the target battery is greater than or equal to C0, the analysis module retests the target battery to obtain a corrected capacity D3' for the first step discharge, thereby ensuring the validity of the test data and improving the lithium plating detection efficiency. If the capacity D3 of the first step discharge of the target battery is less than C0, the analysis module compares the target battery judgment value E1 with the first threshold E0. Based on the comparison result of E1 and E0, the lithium plating risk of the target battery is obtained, thereby initially determining whether the target battery is normal and improving the battery's performance. To improve lithium plating detection efficiency, after obtaining the capacity D3' of the first step discharge of the target battery, the analysis module analyzes the target battery. When the capacity D3' of the first step discharge of the target battery is greater than or equal to C0, the analysis module discards the test data of the multi-stage constant voltage discharge unit of the target battery to ensure the validity of the test data. When the capacity D3' of the first step discharge of the target battery is less than C0, the analysis module compares the judgment value E1' of the target battery with the first threshold E0. Based on the comparison result, the lithium plating risk of the target battery is obtained, thereby initially determining whether the target battery is normal and improving the lithium plating detection efficiency of the battery.

[0110] Specifically, the analysis module compares the peaks and valleys of the target battery's differential capacity curve obtained from the low-current charge-discharge unit test with the standard differential capacity curve at preset sixth voltage V6 and preset seventh voltage V7. In this embodiment, V6 = 3.6V and V7 = 3.8V. Based on the comparison results, the target battery's lithium plating risk is determined.

[0111] When the peak and valley of the differential capacity curve of the target battery with the preset sixth voltage V6 shifts to the left relative to the peak and valley of the standard differential capacity curve, and the peak and valley of the differential capacity curve of the target battery with the preset seventh voltage V7 shifts to the right relative to the peak and valley of the standard differential capacity curve, the analysis module determines that data analysis of the target battery is required.

[0112] When the peak and valley of the differential capacity curve of the target battery with the preset sixth voltage V6 shifts to the left relative to the peak and valley of the standard differential capacity curve, and the peak and valley of the differential capacity curve of the target battery with the preset seventh voltage V7 shifts to the left relative to the peak and valley of the standard differential capacity curve, the analysis module determines that no data analysis of the target battery is required.

[0113] When the peaks and valleys of the differential capacity curve of the target battery with the preset sixth voltage V6 shift to the right relative to the peaks and valleys of the standard differential capacity curve, and the peaks and valleys of the differential capacity curve of the target battery with the preset seventh voltage V7 shift to the right relative to the peaks and valleys of the standard differential capacity curve, the analysis module determines that no data analysis of the target battery is required.

[0114] When the peak and valley of the differential capacity curve of the target battery with the preset sixth voltage V6 shifts to the right relative to the peak and valley of the standard differential capacity curve, and the peak and valley of the differential capacity curve of the target battery with the preset seventh voltage V7 shifts to the left relative to the peak and valley of the standard differential capacity curve, the analysis module determines that no data analysis of the target battery is required.

[0115] When data analysis of the target battery is required, the analysis module acquires the incremental capacity analysis threshold H0 of the standard differential capacity curve at the preset sixth voltage V6, the incremental capacity analysis threshold H1 of the differential capacity curve of the target battery at the preset sixth voltage V6, the incremental capacity analysis threshold H2 of the differential capacity curve of the target battery at the preset seventh voltage V7, and the incremental capacity analysis threshold H0' of the differential capacity curve of the target battery at the preset seventh voltage V7. The analysis module compares H0, H1, H0', and H2, and determines the lithium plating risk of the target battery based on the comparison results.

[0116] When H1 < H0, and H1 > H2, H2 < H0', the analysis module determines that the target battery has a risk of lithium plating and marks the target battery as positive;

[0117] When H1 < H0, and H1 > H2, and H2 ≥ H0', the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative;

[0118] When H1 < H0, and H1 ≤ H2, H2 < H0', the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative;

[0119] When H1≥H0, and H1>H2, H2≥H0', the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative;

[0120] When H1≥H0, and H1≤H2, H2≥H0', the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative;

[0121] When H1≥H0, and H1≤H2, H2<H0', the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative.

[0122] Specifically, the analysis module compares the peaks and valleys of the differential capacity curve of the target battery in the low-current charge-discharge unit with the peaks and valleys of the standard differential capacity curve at the preset sixth voltage V6 and preset seventh voltage V7. When the peaks and valleys of the differential capacity curve of the target battery at the preset sixth voltage V6 shift to the left relative to the peaks and valleys of the standard differential capacity curve, and the peaks and valleys of the differential capacity curve of the target battery at the preset seventh voltage V7 shift to the right relative to the peaks and valleys of the standard differential capacity curve, the analysis module compares the incremental capacity analysis thresholds H0, H1, H2, and H0' of the differential capacity curve of the target battery at the preset sixth voltage V6, and marks the target battery according to the comparison results, thereby further determining that the target battery has the risk of lithium plating and improving the lithium plating detection efficiency of the battery.

[0123] Specifically, the analysis module compares the ohmic impedance of the target battery with the standard ohmic impedance, and the sum of the solid electrolyte impedance and the standard solid electrolyte impedance, based on the test results of the low-temperature AC impedance unit. Based on the comparison results, it assesses the lithium plating risk of the target battery, setting the standard ohmic impedance as F0, the sum of the standard solid electrolyte impedance and the standard solid electrolyte impedance as G0, the ohmic impedance of the target battery as F1, and the sum of the solid electrolyte impedance and the standard solid electrolyte impedance as G1.

[0124] When F1 < F0 and G1 > G0, the analysis module determines that the target battery has a risk of lithium plating and marks the target battery as positive.

[0125] When F1 < F0 and G1 ≤ G0, the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative.

[0126] When F1≥F0 and G1>G0, the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative;

[0127] When F1≥F0 and G1≤G0, the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative.

[0128] Specifically, the analysis module compares the ohmic impedance of the target battery with the standard ohmic impedance, and the sum of the solid electrolyte impedance of the target battery and the standard solid electrolyte impedance with the standard solid electrolyte impedance, based on the test results of the low-temperature AC impedance unit. Based on the comparison results, it further determines that the target battery has a risk of lithium plating, marks the target battery, and thus further determines that the target battery has a risk of lithium plating, thereby improving the lithium plating detection efficiency of the battery.

[0129] Specifically, the judgment module determines the battery status based on the battery analysis results, wherein...

[0130] When the target battery is marked as positive in the multi-stage constant voltage discharge analysis, positive in the low current charge-discharge analysis, and positive in the low temperature AC impedance analysis, the judgment module determines that the lithium plating risk of the target battery is Class A risk.

[0131] When the target battery is marked as positive in the multi-stage constant voltage discharge analysis, negative in the low current charge-discharge analysis, and positive in the low temperature AC impedance analysis, the judgment module determines that the lithium plating risk of the target battery is Grade A.

[0132] When the target battery is marked as positive in the multi-stage constant voltage discharge analysis, positive in the low current charge-discharge analysis, and negative in the low temperature AC impedance analysis, the judgment module determines that the lithium plating risk of the target battery is Grade A.

[0133] When the target battery is marked as negative in the multi-stage constant voltage discharge analysis, positive in the low current charge-discharge analysis, and positive in the low temperature AC impedance analysis, the judgment module determines that the lithium plating risk of the target battery is grade B.

[0134] When the target battery is marked as positive in the multi-stage constant voltage discharge analysis, negative in the low current charge-discharge analysis, and negative in the low temperature AC impedance analysis, the judgment module determines that the lithium plating risk of the target battery is grade B.

[0135] When the target battery is marked as negative in the multi-stage constant voltage discharge analysis, positive in the low current charge-discharge analysis, and negative in the low temperature AC impedance analysis, the judgment module determines that the lithium plating risk of the target battery is grade B.

[0136] When the target battery is marked as negative in the multi-stage constant voltage discharge analysis, negative in the low current charge-discharge analysis, and positive in the low temperature AC impedance analysis, the judgment module determines that the lithium plating risk of the target battery is grade B.

[0137] When the target battery is marked as negative in the multi-stage constant voltage discharge analysis, negative in the low current charge-discharge analysis, and negative in the low temperature AC impedance analysis, the judgment module determines that the target battery does not have a risk of lithium plating.

[0138] Specifically, the judgment module determines the battery state based on the target battery's markings in the battery analysis results, thereby further classifying the lithium plating risk level and improving the lithium plating detection efficiency. It is understood that this embodiment does not specifically limit the method for judging the battery state; those skilled in the art can freely set it according to actual needs, such as setting weights for parameters based on different scenarios and stages, and then scoring them for judgment.

[0139] Specifically, the processing module processes the target battery according to its battery state, wherein...

[0140] When the target battery is classified as a Class A risk, the processing module determines that the target battery is an aged battery and requires capacity repair.

[0141] When the target battery is classified as a Class B risk, the processing module selects the test data marked as positive for the target battery, compares each test data with each standard threshold, and judges the target battery based on the comparison results. If there is a test data value greater than twice the standard threshold, the processing module determines that the battery is an aged battery and needs to be repaired. If there is no test data value greater than twice the standard threshold, the processing module determines that the battery is not an aged battery and can be restored during the next maintenance.

[0142] When the target battery does not have the risk of lithium plating, the processing module determines that the target battery is an aged battery and does not require capacity repair.

[0143] Specifically, the repair module discharges the target battery that needs capacity repair with a preset first repair current C1'. When the discharge reaches the cutoff voltage, which is a preset repair voltage V', the target battery is discharged at a constant voltage to a preset second repair current C2'. In this embodiment, C1'=0.33C, V'=2.5V, and C2'=0.05C.

[0144] Please see Figure 3 As shown, this is a flowchart illustrating the in-situ lithium plating detection and battery capacity repair method of this embodiment. The method includes,

[0145] Step S1: Use the acquisition module to perform an aging test on the fresh battery to obtain the standard threshold values ​​for each parameter of the target battery.

[0146] Step S2: Test data is obtained by testing the target battery through the test module. During the test, the target battery is subjected to multi-stage constant voltage discharge test through the multi-stage constant voltage discharge unit to obtain the capacity D3 of the first step discharge, the capacity D4 of the second step discharge, and the nominal capacity D5 of the target battery. The target battery is subjected to small current charge and discharge test through the small current charge and discharge unit to obtain the discharge capacity D6 and the discharge voltage U1 of the target battery. The target battery is subjected to low temperature AC impedance test through the low temperature AC impedance unit.

[0147] Step S3: The target battery is analyzed by the analysis module according to the standard threshold and test data, and the lithium plating risk of the target battery is judged based on the analysis results. The battery is then marked according to the risk judgment results.

[0148] Step S4: The judgment module determines the battery status based on the target battery's markings.

[0149] Step S5: The processing module determines whether the target battery is an aged battery based on the battery status.

[0150] Step S6: Repair the aging battery using the repair module.

[0151] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A battery in-situ lithium plating detection and battery capacity repair system, characterized in that, include, The acquisition module is used to perform aging tests on fresh batteries to obtain standard thresholds for various parameters of the target battery; The testing module is used to test the target battery and obtain test data. The testing module includes a multi-stage constant voltage discharge unit, a low-current charge-discharge unit, and a low-temperature AC impedance unit. The multi-stage constant voltage discharge unit is used to perform multi-stage constant voltage discharge tests on the target battery to obtain the capacity D3 of the first step discharge, the capacity D4 of the second step discharge, and the nominal capacity D5 of the target battery. The low-current charge-discharge unit is used to perform low-current charge-discharge tests on the target battery to obtain the discharge capacity D6 and the discharge voltage U1 of the target battery. The low-temperature AC impedance unit is used to perform low-temperature AC impedance tests on the target battery to obtain the ohmic impedance of the target battery and the sum of the solid electrolyte impedance and the solid electrolyte impedance. The analysis module is used to analyze the target battery based on the standard threshold obtained by the acquisition module and the test data obtained by the test module. This includes analyzing the lithium plating risk of the target battery based on the capacity D3 of the first step discharge, analyzing the lithium plating risk of the target battery based on the differential capacity curve of the target battery, and analyzing the lithium plating risk of the target battery based on the ohmic impedance of the target battery, so as to determine the lithium plating risk of the target battery. The analysis module marks the target battery for different analysis processes, marking it as positive when there is a lithium plating risk and marking it as negative when there is no lithium plating risk. The judgment module is used to determine the battery status based on the markings of the target battery in the battery analysis results. The battery status includes A-level risk, B-level risk, and no lithium plating risk. The processing module is used to process the target battery according to the battery status, and to determine whether the target battery is an aged battery and whether it needs capacity repair. The repair module is used to repair aging batteries.

2. The battery in-situ lithium plating detection and battery capacity repair system according to claim 1, characterized in that, The acquisition module performs aging tests on fresh batteries and uses the test results as standard thresholds for corresponding parameters of the target battery. The aging tests include multi-stage constant voltage discharge tests, low-current charge-discharge tests, and low-temperature AC impedance tests. During multi-stage constant voltage discharge testing, the acquisition module charges the fresh battery with constant current to a preset first voltage V1 under a preset first current C1, and then charges it with constant voltage to a preset second current C2 to obtain the capacity D1 of the standard first step discharge. After a preset first time interval ΔT1, the fresh battery is discharged with constant current to a preset second voltage V2 under a preset second current C2, and then discharged with constant voltage to a preset third current C3 to obtain the capacity D2 of the standard second step discharge. The first threshold is set as E0, and the nominal capacity of the battery is D. E0 = D2 / D. The nominal capacity of the battery is D, which refers to the discharge capacity of the battery when discharged at 0.2C, where C is the C-rate of the battery. During the low-current charge-discharge test, the acquisition module charges the fresh battery with constant current to a preset third voltage V3 under a preset third current C3, then charges it with constant voltage to a preset fourth current C4, and sets it for a preset second time interval ΔT2. Under a preset fifth current C5, the battery discharges with constant current to a preset fourth voltage V4, and sets it for a preset second time interval ΔT2. Under a preset fifth current C5, the battery is charged with constant current to a preset fifth voltage V5, and then set for a preset second time interval ΔT2. The standard discharge capacity D0 and standard discharge voltage U0 are obtained. Incremental capacity analysis is performed based on the standard discharge capacity D0 and standard discharge voltage U0, and the dQ / dV-V differential capacity curve is plotted to obtain the standard differential capacity curve. During the low-temperature AC impedance test, the acquisition module charges the fresh battery to a preset power battery charge SOC1 under preset first temperature T1 and preset sixth current C6 conditions. After being left to stand at a preset second temperature T2 for a preset third time interval ΔT3, the AC impedance test is performed, the real part-imaginary part curve of the AC impedance is plotted, and a second-order RC circuit is used to fit the standard ohmic impedance and the sum of the standard solid electrolyte impedance and the solid electrolyte impedance. The standard ohmic impedance is set as F0, and the sum of the standard solid electrolyte impedance and the solid electrolyte impedance is set as G0.

3. The battery in-situ lithium plating detection and battery capacity repair system according to claim 1, characterized in that, When testing the target battery, the multi-stage constant voltage discharge unit charges the target battery with constant current to a preset first voltage V1 under a preset first current C1, and then charges it with constant voltage to a preset second current C2 to obtain the capacity D3 of the first step discharge of the target battery. After being left to stand for a preset first time interval ΔT1, it discharges with constant current to a preset second voltage V2 under a preset second current C2, and then discharges it with constant voltage to a preset third current C3 to obtain the capacity D4 of the second step discharge of the target battery. The low-current charging and discharging unit charges the target battery with constant current to a preset third voltage V3 under a preset third current C3, then charges it with constant voltage to a preset fourth current C4, and sets it for a preset second time interval ΔT2. Then, it discharges the target battery with constant current to a preset fourth voltage V4 under a preset fifth current C5, sets it for a preset second time interval ΔT2, charges the target battery with constant current to a preset fifth voltage V5 under a preset fifth current C5, and sets it for a preset second time interval ΔT2. The discharge capacity D6 and discharge voltage U1 of the target battery are obtained. Incremental capacity analysis is performed based on the discharge capacity D6 and discharge voltage U1 of the target battery, and the dQ / dV-V differential capacity curve is plotted to obtain the differential capacity curve of the target battery. The low-temperature AC impedance unit charges the target battery to SOC1 under a preset first temperature T1 and a preset sixth current C6. After being left to stand at a preset second temperature T2 for a preset third time interval ΔT3, an AC impedance test is performed. The real-imaginary part curve of the AC impedance is plotted, and a second-order RC circuit is used to fit the target battery to obtain the ohmic impedance and the sum of the solid electrolyte impedance and the solid electrolyte impedance. The ohmic impedance of the target battery is set as F1, and the sum of the solid electrolyte impedance and the solid electrolyte impedance is set as G1.

4. The battery in-situ lithium plating detection and battery capacity repair system according to claim 1, characterized in that, The analysis module compares the capacity D3 of the first step discharge of the target battery with the preset discharge capacity C0, and analyzes the lithium plating risk of the target battery based on the comparison results. When D3 < C0, the target battery determination value is set to E1, and E1 = D4 / D5. The analysis module compares E1 with E0 and analyzes the lithium plating risk of the target battery based on the comparison result. If E1≥E0, the analysis module determines that the target battery has a risk of lithium plating and marks the target battery as positive; If E1 < E0, the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative; When D3≥C0, the analysis module retests the target battery to obtain the capacity D3' of the first step discharge of the corrected target battery, where, When D3'≥C0, the analysis module discards the test data of the multi-stage constant voltage discharge unit of the target battery; When D3' < C0, the analysis module obtains the capacity D4' of the second step discharge of the target battery, sets the target battery determination value to E1', and E1' = D4' / D5. The analysis module compares E1' with E0 and analyzes the lithium plating risk of the target battery based on the comparison results. If E1'≥E0, the analysis module determines that the target battery has a risk of lithium plating and marks the target battery as positive; If E1' < E0, the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative.

5. The battery in-situ lithium plating detection and battery capacity repair system according to claim 4, characterized in that, The analysis module compares the peaks and valleys of the target battery's differential capacity curve obtained from the low-current charge-discharge unit test with the standard differential capacity curve at the preset sixth voltage V6 and preset seventh voltage V7, and determines the lithium plating risk of the target battery based on the comparison results. When the peak and valley of the differential capacity curve of the target battery with the preset sixth voltage V6 shifts to the left relative to the peak and valley of the standard differential capacity curve, and the peak and valley of the differential capacity curve of the target battery with the preset seventh voltage V7 shifts to the right relative to the peak and valley of the standard differential capacity curve, the analysis module determines that data analysis of the target battery is required. When the peak and valley of the differential capacity curve of the target battery with the preset sixth voltage V6 shifts to the left relative to the peak and valley of the standard differential capacity curve, and the peak and valley of the differential capacity curve of the target battery with the preset seventh voltage V7 shifts to the left relative to the peak and valley of the standard differential capacity curve, the analysis module determines that no data analysis of the target battery is required. When the peaks and valleys of the differential capacity curve of the target battery with the preset sixth voltage V6 shift to the right relative to the peaks and valleys of the standard differential capacity curve, and the peaks and valleys of the differential capacity curve of the target battery with the preset seventh voltage V7 shift to the right relative to the peaks and valleys of the standard differential capacity curve, the analysis module determines that no data analysis of the target battery is required. When the peak and valley of the differential capacity curve of the target battery with the preset sixth voltage V6 shifts to the right relative to the peak and valley of the standard differential capacity curve, and the peak and valley of the differential capacity curve of the target battery with the preset seventh voltage V7 shifts to the left relative to the peak and valley of the standard differential capacity curve, the analysis module determines that no data analysis of the target battery is required. When data analysis of the target battery is required, the analysis module acquires the incremental capacity analysis threshold H0 of the standard differential capacity curve at the preset sixth voltage V6, the incremental capacity analysis threshold H1 of the differential capacity curve of the target battery at the preset sixth voltage V6, the incremental capacity analysis threshold H2 of the differential capacity curve of the target battery at the preset seventh voltage V7, and the incremental capacity analysis threshold H0' of the differential capacity curve of the target battery at the preset seventh voltage V7. The analysis module compares H0, H1, H0', and H2, and determines the lithium plating risk of the target battery based on the comparison results. When H1 < H0, and H1 > H2, H2 < H0', the analysis module determines that the target battery has a risk of lithium plating and marks the target battery as positive; When H1 < H0, and H1 > H2, and H2 ≥ H0', the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative; When H1 < H0, and H1 ≤ H2, H2 < H0', the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative; When H1≥H0, and H1>H2, H2≥H0', the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative; When H1≥H0, and H1≤H2, H2≥H0', the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative; When H1≥H0, and H1≤H2, H2<H0', the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative.

6. The battery in-situ lithium plating detection and battery capacity repair system according to claim 5, characterized in that, The analysis module compares the ohmic impedance of the target battery with the standard ohmic impedance, and the sum of the solid electrolyte impedance and the standard solid electrolyte impedance, based on the test results of the low-temperature AC impedance unit. Based on the comparison results, it assesses the lithium plating risk of the target battery. The standard ohmic impedance is defined as F0, the sum of the standard solid electrolyte impedance and the standard solid electrolyte impedance as G0, the ohmic impedance of the target battery as F1, and the sum of the solid electrolyte impedance and the standard solid electrolyte impedance as G1. When F1 < F0 and G1 > G0, the analysis module determines that the target battery has a risk of lithium plating and marks the target battery as positive. When F1 < F0 and G1 ≤ G0, the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative. When F1≥F0 and G1>G0, the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative; When F1≥F0 and G1≤G0, the analysis module determines that the target battery does not have a risk of lithium plating and marks the target battery as negative.

7. The battery in-situ lithium plating detection and battery capacity repair system according to claim 1, characterized in that, The judgment module determines the battery status based on the battery analysis results, wherein... When the target battery is marked as positive in the multi-stage constant voltage discharge analysis, positive in the low current charge-discharge analysis, and positive in the low temperature AC impedance analysis, the judgment module determines that the lithium plating risk of the target battery is Class A risk. When the target battery is marked as positive in the multi-stage constant voltage discharge analysis, negative in the low current charge-discharge analysis, and positive in the low temperature AC impedance analysis, the judgment module determines that the lithium plating risk of the target battery is Grade A. When the target battery is marked as positive in the multi-stage constant voltage discharge analysis, positive in the low current charge-discharge analysis, and negative in the low temperature AC impedance analysis, the judgment module determines that the lithium plating risk of the target battery is Grade A. When the target battery is marked as negative in the multi-stage constant voltage discharge analysis, positive in the low current charge-discharge analysis, and positive in the low temperature AC impedance analysis, the judgment module determines that the lithium plating risk of the target battery is grade B. When the target battery is marked as positive in the multi-stage constant voltage discharge analysis, negative in the low current charge-discharge analysis, and negative in the low temperature AC impedance analysis, the judgment module determines that the lithium plating risk of the target battery is grade B. When the target battery is marked as negative in the multi-stage constant voltage discharge analysis, positive in the low current charge-discharge analysis, and negative in the low temperature AC impedance analysis, the judgment module determines that the lithium plating risk of the target battery is grade B. When the target battery is marked as negative in the multi-stage constant voltage discharge analysis, negative in the low current charge-discharge analysis, and positive in the low temperature AC impedance analysis, the judgment module determines that the lithium plating risk of the target battery is grade B. When the target battery is marked as negative in the multi-stage constant voltage discharge analysis, negative in the low current charge-discharge analysis, and negative in the low temperature AC impedance analysis, the judgment module determines that the target battery does not have a risk of lithium plating.

8. The battery in-situ lithium plating detection and battery capacity repair system according to claim 1, characterized in that, The processing module processes the target battery according to its battery status, wherein... When the target battery is classified as a Class A risk, the processing module determines that the target battery is an aged battery and requires capacity repair. When the target battery is classified as a Class B risk, the processing module selects the test data marked as positive for the target battery, compares each test data with each standard threshold, and judges the target battery based on the comparison results. If there is a test data value greater than twice the standard threshold, the processing module determines that the battery is an aged battery and needs to be repaired. If there is no test data value greater than twice the standard threshold, the processing module determines that the battery is not an aged battery and can be restored during the next maintenance. When the target battery does not have the risk of lithium plating, the processing module determines that the target battery is an aged battery and does not require capacity repair.

9. The battery in-situ lithium plating detection and battery capacity repair system according to claim 1, characterized in that, The repair module discharges the target battery that needs capacity repair with a preset first repair current C1'. When the discharge reaches the cutoff voltage of the preset repair voltage V', the target battery is discharged at a constant voltage to the preset second repair current C2'.

10. A method for in-situ lithium plating detection and battery capacity repair in batteries as described in any one of claims 1-9, characterized in that, include, Step S1: Use the acquisition module to perform an aging test on the fresh battery to obtain the standard threshold values ​​for each parameter of the target battery. Step S2: Test data is obtained by testing the target battery through the test module. During the test, the target battery is subjected to multi-stage constant voltage discharge test through the multi-stage constant voltage discharge unit to obtain the capacity D3 of the first step discharge, the capacity D4 of the second step discharge, and the nominal capacity D5 of the target battery. The target battery is subjected to small current charge and discharge test through the small current charge and discharge unit to obtain the discharge capacity D6 and the discharge voltage U1 of the target battery. The target battery is subjected to low temperature AC impedance test through the low temperature AC impedance unit. Step S3: The target battery is analyzed by the analysis module according to the standard threshold and test data, and the lithium plating risk of the target battery is judged based on the analysis results. The battery is then marked according to the risk judgment results. Step S4: The judgment module determines the battery status based on the target battery's markings. Step S5: The processing module determines whether the target battery is an aged battery based on the battery status. Step S6: Repair the aging battery using the repair module.

Images