Lithium supplement effect detection method, device and system of lithium ion battery

Abstract

The invention discloses a lithium supplement effect detection method, device and system for a lithium ion battery, and relates to the technical field of batteries. A specific embodiment of the method comprises the following steps: measuring an open-circuit voltage of a battery in a discharge process of the battery to be detected, and constructing a change curve of the open-circuit voltage along with a charge state for the battery; extracting distortion characteristic parameters for the battery according to a curve segment not higher than a charge state threshold value in the change curve; wherein the state-of-charge threshold value is related to the disturbance of residual metal lithium introduced by the battery to the open-circuit voltage; and evaluating the lithium supplement effect of the battery based on the distortion characteristic parameters. According to the implementation mode, rapid nondestructive detection of the battery on the production line is achieved, the negative electrode lithium supplement effect can be quantitatively evaluated by analyzing the distortion characteristic parameters of the open-circuit voltage of the battery to be detected along with the change of the charge state, and compared with a traditional disassembly detection mode, the cost can be greatly reduced, and the detection efficiency can be greatly improved.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a method, apparatus, and system for detecting the lithium replenishment effect of lithium-ion batteries. Background Technology

[0002] Lithium-ion batteries are widely used in portable electronic devices, energy storage systems, and electric vehicles due to their advantages such as high energy density, long cycle life, and environmental friendliness. Traditional battery testing methods, such as disassembly and observation, scanning electron microscopy analysis, and neutron diffraction, are complex, costly, and destructive, making them unsuitable for online testing and thus affecting the accurate determination of battery lithium replenishment effectiveness. Summary of the Invention

[0003] In view of this, embodiments of the present invention provide a method, apparatus and system for detecting the lithium replenishment effect of lithium-ion batteries, which can at least solve the problems of complex operation, high cost and destructive nature of battery detection in the prior art.

[0004] To achieve the above objectives, according to one aspect of the present invention, a method for detecting the lithium replenishment effect of a lithium-ion battery is provided, comprising: The open-circuit voltage of the battery under test is measured during the discharge process to construct a curve of the open-circuit voltage versus state of charge for the battery. Based on the curve segments in the change curve that are not higher than the state of charge threshold, distortion characteristic parameters are extracted for the battery; wherein, the state of charge threshold is related to the disturbance of open circuit voltage caused by residual lithium metal introduced by the battery. The lithium replenishment effect of the battery is evaluated based on the aforementioned distortion characteristic parameters.

[0005] To achieve the above objectives, according to another aspect of the present invention, a lithium-ion battery lithium replenishment effect detection device is provided, comprising: The discharge measurement module is used to measure the open-circuit voltage of the battery during the discharge process of the battery under test, and to construct a curve of the change of open-circuit voltage with state of charge for the battery. The parameter extraction module is used to extract distortion characteristic parameters for the battery based on the curve segments in the change curve that are not higher than the state of charge threshold; wherein, the state of charge threshold is related to the disturbance of the open circuit voltage caused by the residual lithium metal introduced by the battery. An evaluation module is used to evaluate the lithium replenishment effect of the battery based on the distortion characteristic parameters.

[0006] To achieve the above objectives, according to another aspect of the present invention, a lithium-ion battery lithium replenishment effect detection system is provided, comprising: a state of charge detection device, an open circuit voltage detection device, and a lithium-ion battery lithium replenishment effect detection device.

[0007] To achieve the above objectives, according to another aspect of the present invention, an electronic device for detecting the lithium replenishment effect of a lithium-ion battery is provided.

[0008] The electronic device of this invention includes: one or more processors; and a storage device for storing one or more programs, which, when executed by the one or more processors, enable the one or more processors to implement the lithium replenishment effect detection method for any of the above-described lithium-ion batteries.

[0009] To achieve the above objectives, according to another aspect of the present invention, a computer-readable medium is provided having a computer program stored thereon, which, when executed by a processor, implements the lithium replenishment effect detection method for any of the above-described lithium-ion batteries.

[0010] To achieve the above objectives, according to another aspect of the present invention, a computing program product is provided. One computing program product of the present invention includes a computer program, which, when executed by a processor, implements the lithium-ion battery lithium replenishment effect detection method provided in the present invention.

[0011] According to the solution provided by the present invention, one embodiment of the invention has the following advantages or beneficial effects: it achieves rapid and non-destructive testing of batteries; by analyzing the distortion characteristic parameters of the battery's open-circuit voltage as a function of state of charge, it can quantitatively evaluate the quality of the negative electrode lithium replenishment process, including key indicators such as residual lithium replenishing agent and uniformity of distribution. Furthermore, the method is simple to operate, saves testing time, improves battery testing efficiency and quality control level, and provides effective technical support for optimizing battery manufacturing processes.

[0012] The further effects of the aforementioned unconventional alternative methods will be explained below in conjunction with specific implementation methods. Attached Figure Description

[0013] The accompanying drawings are provided to better understand the invention and are not intended to unduly limit the scope of the invention. Wherein: Figure 1 This is a schematic diagram of the main process of a lithium-ion battery lithium replenishment effect detection method according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the main modules of a lithium-ion battery lithium replenishment effect testing device according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the main architecture of a lithium-ion battery lithium replenishment effect detection system according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a computer system suitable for implementing the embodiments of the present invention, such as a mobile device or server. Detailed Implementation

[0014] The following description, in conjunction with the accompanying drawings, illustrates exemplary embodiments of the present invention, including various details to aid understanding. These details should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the invention. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0015] It should be noted that the collection, gathering, updating, analysis, processing, use, transmission, and storage of user personal information involved in this disclosed technical solution all comply with relevant laws and regulations, are used for legitimate purposes, and do not violate public order and good morals. Necessary measures are taken to prevent unauthorized access to user personal information data and to safeguard user personal information security, network security, and national security.

[0016] The following are explanations of the terms used in this plan: SOC (State of Charge) represents the ratio of a battery's current remaining charge to its total capacity. SOC describes the degree of battery charge and is usually expressed as a percentage.

[0017] OCV (Open Circuit Voltage) represents the voltage difference between the positive and negative terminals of a battery when no external load is connected. During OCV measurement, the battery is not charging or discharging and is in an open-circuit state.

[0018] See Figure 1 The diagram shows the main flowchart of a lithium-ion battery lithium replenishment effect detection method provided by an embodiment of the present invention, which includes the following steps: S101: Measure the open-circuit voltage of the battery during the discharge process of the battery under test, and construct a curve of the change of open-circuit voltage with state of charge for the battery. S102: Based on the curve segments in the change curve that are not higher than the state of charge threshold, extract distortion characteristic parameters for the battery; wherein, the state of charge threshold is related to the disturbance of open circuit voltage caused by residual lithium metal introduced by the battery. S103: Evaluate the lithium replenishment effect of the battery based on the distortion characteristic parameters.

[0019] As batteries age, their performance gradually declines, necessitating performance recovery through negative electrode lithium replenishment. Negative electrode lithium replenishment refers to the process of adding lithium ions to the negative electrode during lithium battery manufacturing or repair. This process aims to compensate for lithium ion loss during battery cycling, restoring battery capacity and performance. It is typically achieved by adding lithium compounds or metallic lithium to the negative electrode. This method is used to test the effectiveness of battery lithium replenishment and includes the following steps: In step S101, after the battery to be tested is charged and activated, it is then discharged. During the discharge process, the open-circuit voltage (OCV) of the battery is measured at preset state-of-charge (SOC) intervals to establish a correspondence between OCV and SOC. The preset SOC interval can be set according to actual needs, such as 1%, 0.5%, or 2%. Preferably, the battery's OCV is measured every 1% decrease in SOC. Then, based on the correspondence between OCV and SOC, a curve showing the change of OCV with SOC is constructed.

[0020] It should be noted that, to ensure measurement accuracy, the battery should be allowed to stand for a certain period of time (e.g., 2 hours) before each OCV measurement to eliminate the polarization effect generated during charging and discharging. Polarization can cause the measured voltage to deviate from the true open-circuit voltage. Allowing the battery to stand for a sufficient period of time allows it to reach an electrochemical equilibrium state, thereby improving the accuracy of OCV measurements.

[0021] In one alternative implementation, the battery's state of charge (OCC) needs to be reduced to a preset termination state. The preset termination state is such as 0%, meaning the battery is fully discharged; however, other values ​​can also be considered and are not limited here. For 0%, the measured OCV is the OCV of the battery from a fully charged state to a fully discharged state.

[0022] In one optimized implementation, to improve detection efficiency and reduce data acquisition, the fully charged battery can be discharged to a preset first range (e.g., 15-20%) before OCV measurement begins. For example, OCV measurement can begin when the battery's SOC drops to 18% and continue until the battery is fully discharged. This ensures the integrity of OCV data in the critical range while reducing unnecessary measurement points.

[0023] In another optional implementation, the battery can be discharged at a constant current at a preset discharge rate (e.g., 0.1C, where C is the battery's rated capacity). 0.1C is a low-rate discharge, which can effectively reduce polarization effects, obtain more accurate OCV, and has a relatively small impact on battery life. Depending on different detection accuracy requirements, other suitable discharge rates, such as 0.05C or 0.2C, can also be selected.

[0024] For step S102, after constructing the OCV versus SOC curve, distortion characteristic parameters are extracted from the curve. In an optional implementation, it is not necessary to extract distortion characteristic parameters from the entire curve; instead, a specific segment of the curve is selected for analysis. Considering the residual lithium metal introduced during the negative electrode lithium replenishment process, the oxidation reaction of this lithium metal mainly affects the OCV in the low SOC range, typically between 5% and 15%. Therefore, a state of charge threshold, such as 15%, can be set to consider only the segment of the curve with an SOC less than or equal to 15%.

[0025] In one optimized implementation, the state of charge (SOC) corresponding to this portion of the curve falls within a preset second interval, for example, 5% to 15%. Therefore, by focusing on analyzing the curve distortion characteristics of the second interval, the lithium replenishment effect can be reflected more effectively. The aforementioned preset first interval is assumed to be 20%, meaning that it extends forward and backward by 5% from 5% to 15%, thus measuring the OCV as a function of SOC between 0% and 20%. The second interval (5% to 15%) is typically smaller than the aforementioned first interval (15% to 20%). This interval setting strategy ensures sufficient detection of key disturbance areas while avoiding the influence of interference signals from other intervals, improving the targeting and accuracy of the detection.

[0026] The distortion characteristic parameters mainly include the hump voltage value ΔV, the standard deviation of the plateau slope σ, and the initial SOCs of the distortion. In an optional embodiment, the hump area A may also be included. The hump area A physically represents the total amount of residual lithium, but this parameter is not used in this scheme to reduce computational complexity. Taking the case where the SOC is located in the preset second range (5%~15%) as an example, the calculation method of each distortion characteristic parameter is as follows: The peak voltage value ΔV is calculated as follows: ΔV = max (OCV) - min (OCV), which is the difference between the maximum and minimum values ​​of OCV within this interval.

[0027] The standard deviation of the platform slope, σ, is calculated as follows: σ = std(dOCV / dSOC) @ 5%~15%SOC, representing the standard deviation of the derivative of OCV with respect to SOC within the SOC range of 5%~15%. Here, dOCV / dSOC is the derivative of OCV with respect to SOC, reflecting the slope of the SOC-OCV curve and describing the change in OCV for each unit change in SOC. A smaller standard deviation indicates a smoother OCV-SOC curve and a more uniform lithium replenishment distribution within that range.

[0028] The distortion initiation point (SOCs) is calculated as follows: the first time the OC is satisfied... -OC The SOC point >5mV (x≥5%) refers to the smaller SOC when the OCV difference between two adjacent SOC points exceeds 5mV. Where OC... Let OC be the open-circuit voltage corresponding to the current SOC point x. This represents the open-circuit voltage corresponding to the previous SOC point (x-1), with 5mV being a preset voltage difference threshold. This method can accurately locate the starting point of a significant voltage jump in the OCV curve.

[0029] The physical meaning of the distortion initiation point (SOCs) is: it represents the "starting point" where the most active residual lithium in the battery begins to undergo oxidation. The main reason for limiting x to ≥ 5% in the calculation is to avoid the "noise zone" of the low SOC region, ensuring that the detected signal is a genuine lithium replenishment signal rather than other interfering factors. The 0~5% SOC range is a high-noise, low-signal-to-noise ratio region, which is not conducive to accurate judgment. Therefore, detection is started from 5% SOC to improve the accuracy and reliability of the detection results.

[0030] For step S103, the lithium replenishment effect of the battery is evaluated based on the extracted distortion characteristic parameters, including indicators such as the residual amount and distribution uniformity of the lithium replenishing agent. In an optional embodiment, the cell grade can be determined based on these distortion characteristic parameters, and then the battery's qualification can be determined based on the cell grade. This scheme pre-sets a quantitative relationship between distortion characteristic parameters and lithium replenishment effect, as shown in Table 1: Table 1 Quantitative Relationship

[0031] Accordingly, this solution also pre-defines the judgment rules, with different characteristic parameter ranges corresponding to different cell grades, as shown in Table 2: Table 2 Cell Grade Determination Rules

[0032] The above criteria can be used to assess the quality of actual batteries. The test results are as follows: Battery No. 1: ΔV is 35.2mV, σ is 0.0028, SOCs is 2.1%, the judgment result is C level, and disassembly verification shows that there is surface lithium plating.

[0033] Battery No. 2: ΔV is 18.3mV, σ is 0.0015, SOCs is 4.8%, the judgment result is B grade, and disassembly verification shows that there is uniform residual lithium inside.

[0034] Battery No. 3: ΔV is 8.7mV, σ is 0.0035, SOCs is 5.3%, the judgment result is Grade A. Disassembly verification shows that residual lithium is deeply buried and there is no surface lithium plating.

[0035] Test results show that this solution can effectively distinguish batteries with different lithium replenishment effects and has good consistency with the disassembly verification results.

[0036] In one optional implementation, the test subjects of this scheme include: lithium batteries from the same batch treated with different lithium replenishment dosages or processes, and unreplenished lithium batteries as a control group. For each battery in the batch, the same technical solution is used to detect its battery health status, and corresponding evaluation results are obtained. Using the evaluation results of unreplenished batteries as a benchmark, the correlation between lithium replenishment dosage and lithium replenishment effect is established by comparing and analyzing the evaluation results of batteries with different lithium replenishment dosages, providing data support for optimizing the lithium replenishment process.

[0037] It is understood that the specific values ​​listed in the above hypothetical description of the lithium replenishment effect test of lithium-ion batteries are only illustrative examples and not restrictive. In practice, other values ​​can be set according to needs. Similarly, the specific values ​​listed in the subsequent embodiments are only examples and are not the only limitation.

[0038] The method provided in the above embodiments can quantitatively evaluate the effectiveness of the negative electrode lithium replenishment process by analyzing the distortion characteristic parameters of the open-circuit voltage of the battery under test as it changes with the state of charge. This includes key indicators such as the residual amount of lithium replenishing agent and its distribution uniformity. This method enables rapid non-destructive testing on the production line and can complete the evaluation of the lithium replenishment effect of the battery in a very short time (e.g., 1 minute). Compared with traditional disassembly and testing methods, it can significantly reduce costs and improve testing efficiency.

[0039] Furthermore, this method supports quality assessment during the initial capacity grading stage, significantly reducing testing time and substantially improving the testing efficiency and quality control level of battery production, providing effective technical support for optimizing battery manufacturing processes. The capacity grading stage is a crucial step in battery production, referring to the determination of the battery's actual capacity and performance parameters through charge-discharge testing. This process allows for precise grading of batteries according to their capacity, ensuring the consistency and reliability of performance within the same batch. Capacity grading is typically performed after the battery formation process and is an important quality control step before batteries leave the factory.

[0040] See Figure 2 The diagram shows the main modules of a lithium-ion battery lithium replenishment effect detection device 200 provided in an embodiment of the present invention, including: The discharge measurement module 201 is used to measure the open-circuit voltage of the battery during the discharge process of the battery under test, and to construct a curve of the change of open-circuit voltage with state of charge for the battery. The parameter extraction module 202 is used to extract distortion characteristic parameters for the battery based on the curve segments in the change curve that are not higher than the state of charge threshold; wherein, the state of charge threshold is related to the disturbance of the open circuit voltage caused by the residual lithium metal introduced by the battery. Evaluation module 203 is used to evaluate the lithium replenishment effect of the battery based on the distortion characteristic parameters.

[0041] In the device of the present invention, the discharge measurement module 201 is used to measure the open-circuit voltage of the battery during the discharge process in which the battery decreases from its current state of charge to a preset termination state.

[0042] In the device of the present invention, the discharge measurement module 201 is further configured to: start measuring the open-circuit voltage of the battery when the state of charge of the battery is detected to drop to a preset first range.

[0043] In the device of this invention, the preset first interval is 15%~20%.

[0044] In the device of the present invention, the discharge measurement module 201 is further used to measure the open-circuit voltage of the battery according to a preset state of charge interval.

[0045] In the device of this invention, the parameter extraction module 202 is used to: extract distortion feature parameters for the battery based on the curve segment in the change curve where the state of charge is located in a preset second interval.

[0046] In the apparatus of this invention, the preset second interval is 5%~15%.

[0047] In the device of this invention, the distortion characteristic parameters include at least one of the following: hump voltage value, plateau slope standard deviation, and distortion initiation state of charge. The process of determining the hump voltage value includes: obtaining the maximum open circuit voltage and the minimum open circuit voltage, and taking the difference between the maximum open circuit voltage and the minimum open circuit voltage as the hump voltage value; The process of determining the standard deviation of the platform slope includes: calculating the standard deviation of the derivative of the open-circuit voltage with respect to the state of charge, and using the standard deviation as the standard deviation of the platform slope; The process of determining the distortion initiation state of charge includes: starting from the minimum state of charge, calculating the voltage difference between the open circuit voltages corresponding to two adjacent states of charge, determining the target two adjacent states of charge with the first voltage difference greater than or equal to a preset voltage difference threshold, and taking the smaller state of charge among the target two adjacent states of charge as the distortion initiation state of charge.

[0048] In the apparatus of this invention, the evaluation module 203 is used for: The range in which the distortion characteristic parameters fall is determined, and the cell grade is matched based on the range. The lithium replenishment effect corresponding to the cell grade is taken as the lithium replenishment effect of the battery.

[0049] In the apparatus of the present invention, the discharge measurement module 201 is further configured to: discharge the battery at a preset discharge rate; wherein the preset discharge rate is determined based on a preset coefficient and the rated capacity of the battery.

[0050] The apparatus for implementing this invention further includes a comparison module, used for: The evaluation results of batteries with different lithium replenishment doses and the evaluation results of batteries without lithium replenishment are obtained from the same batch. The evaluation results of batteries without lithium replenishment are used as a benchmark to compare the evaluation results of batteries with different lithium replenishment doses, so as to generate the correspondence between lithium replenishment dose and lithium replenishment effect.

[0051] Furthermore, the specific implementation details of the device described in the embodiments of the present invention have been described in detail in the above-described method, so the details will not be repeated here.

[0052] See Figure 3 This invention also provides a lithium-ion battery lithium replenishment effect detection system 300, including a state of charge (SCC) detection device 301, an open-circuit voltage (OCV) detection device 302, and a lithium-ion battery lithium replenishment effect detection device 303. The SCC detection device 301 detects the battery's SCC and transmits the data to the lithium replenishment effect detection device 303. When the lithium replenishment effect detection device 303 detects that the SCC has decreased to a preset first range (e.g., 15%~20%), it sends a command to the open-circuit voltage detection device 302 to start measuring the open-circuit voltage. This causes the open-circuit voltage detection device 302 to measure the battery's open-circuit voltage and return the measured open-circuit voltage to the lithium replenishment effect detection device 303. Subsequently, the lithium replenishment effect detection device 303 sends an open-circuit voltage measurement command to the open-circuit voltage detection device 302 every time it detects a 1% decrease in the battery's SCC. The command stops being sent when the battery's SCC reaches a preset termination state. Finally, the lithium replenishment effect detection device 303 constructs a change curve based on the correspondence between the battery's state of charge and open circuit voltage to extract the curve segment where the state of charge is located in a preset second interval (such as 5%~15%), extracts the distortion characteristic parameters of the curve segment, and then evaluates the lithium replenishment effect of the battery based on the distortion characteristic parameters.

[0053] Furthermore, embodiments of the present invention also provide an electronic device. This electronic device may include: one or more processors; and a storage device for storing one or more programs, which, when executed by the one or more processors, cause the one or more processors to provide a method for detecting the lithium replenishment effect of a lithium-ion battery as described in the above embodiments.

[0054] The following is for reference. Figure 4It shows a schematic diagram of the structure of a computer system 400 suitable for implementing a terminal device of the present invention. Figure 4 The terminal device shown is merely an example and should not impose any limitations on the functionality and scope of use of the embodiments of the present invention.

[0055] like Figure 4 As shown, the computer system 400 includes a central processing unit (CPU) 401, which can perform various appropriate actions and processes based on programs stored in read-only memory (ROM) 402 or programs loaded from storage section 408 into random access memory (RAM) 403. The RAM 403 also stores various programs and data required for the operation of the system 400. The CPU 401, ROM 402, and RAM 403 are interconnected via a bus 404. An input / output (I / O) interface 405 is also connected to the bus 404.

[0056] The following components are connected to I / O interface 405: an input section 406 including a keyboard, mouse, etc.; an output section 407 including a cathode ray tube (CRT), liquid crystal display (LCD), etc., and speakers, etc.; a storage section 408 including a hard disk, etc.; and a communication section 409 including a network interface card such as a LAN card, modem, etc. The communication section 409 performs communication processing via a network such as the Internet. Drive 410 is also connected to I / O interface 405 as needed. Removable media 411, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., are installed on drive 410 as needed so that computer programs read from them can be installed into storage section 408 as needed.

[0057] In particular, according to the embodiments disclosed in this invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments disclosed in this invention include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication section 409, and / or installed from removable medium 411. When the computer program is executed by central processing unit (CPU) 401, it performs the functions defined above in the system of this invention.

[0058] It should be noted that the computer-readable medium shown in this invention can be a computer-readable signal medium or a computer-readable storage medium, or any combination thereof. A computer-readable storage medium can be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this invention, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In this invention, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media can also be any computer-readable medium other than computer-readable storage media, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to: wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0059] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0060] The modules described in the embodiments of the present invention can be implemented in software or hardware. The described modules can also be housed in a processor; for example, a processor may be described as including a discharge measurement module, a parameter extraction module, and an evaluation module. The names of these modules do not necessarily limit the module itself; for example, a discharge measurement module may also be described as a "voltage measurement module."

[0061] In another aspect, the present invention also provides a computer-readable medium, which may be included in the device described in the above embodiments; or it may exist independently and not assembled into the device. The computer-readable medium carries one or more programs that, when executed by the device, cause the device to perform any of the lithium-ion battery lithium replenishment effect detection methods described above.

[0062] The computer program product of the present invention includes a computer program that, when executed by a processor, implements the lithium replenishment effect detection method for lithium-ion batteries in the embodiments of the present invention.

[0063] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can occur depending on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for detecting the lithium replenishment effect of a lithium-ion battery, characterized in that, include: The open-circuit voltage of the battery under test is measured during the discharge process to construct a curve of the open-circuit voltage versus state of charge for the battery. Based on the curve segments in the change curve that are not higher than the state of charge threshold, distortion characteristic parameters are extracted for the battery; wherein, the state of charge threshold is related to the disturbance of open circuit voltage caused by residual lithium metal introduced by the battery. The lithium replenishment effect of the battery is evaluated based on the aforementioned distortion characteristic parameters.

2. The method according to claim 1, characterized in that, Measuring the open-circuit voltage of the battery during the discharge process of the battery under test includes: measuring the open-circuit voltage of the battery during the discharge process of the battery from the current state of charge to a preset termination state.

3. The method according to claim 1 or 2, characterized in that, Measuring the open-circuit voltage of the battery during the discharge process of the battery under test further includes: starting to measure the open-circuit voltage of the battery when the state of charge of the battery is detected to drop to a preset first range.

4. The method according to claim 3, characterized in that, The preset first range is 15%~20%.

5. The method according to claim 1, characterized in that, Measuring the open-circuit voltage of the battery during its discharge process further includes measuring the open-circuit voltage of the battery at preset state-of-charge intervals.

6. The method according to claim 1, characterized in that, The step of extracting distortion feature parameters for the battery based on the curve segments in the change curve that are not higher than the state of charge threshold includes: Based on the curve segment in the change curve where the state of charge is located in a preset second interval, distortion characteristic parameters are extracted for the battery.

7. The method according to claim 6, characterized in that, The preset second range is 5% to 15%.

8. The method according to claim 1 or 6, characterized in that, The distortion characteristic parameters include at least one of the following: hump voltage value, plateau slope standard deviation, and distortion initiation state of charge. The process of determining the hump voltage value includes: obtaining the maximum open circuit voltage and the minimum open circuit voltage, and taking the difference between the maximum open circuit voltage and the minimum open circuit voltage as the hump voltage value; The process of determining the standard deviation of the platform slope includes: calculating the standard deviation of the derivative of the open-circuit voltage with respect to the state of charge, and using the standard deviation as the standard deviation of the platform slope; The process of determining the distortion initiation state of charge includes: starting from the minimum state of charge, calculating the voltage difference between the open circuit voltages corresponding to two adjacent states of charge, determining the target two adjacent states of charge with the first voltage difference greater than or equal to a preset voltage difference threshold, and taking the smaller state of charge among the target two adjacent states of charge as the distortion initiation state of charge.

9. The method according to claim 8, characterized in that, The evaluation of the lithium replenishment effect of the battery based on the distortion characteristic parameters includes: The range in which the distortion characteristic parameters fall is determined, and the cell grade is matched based on the range. The lithium replenishment effect corresponding to the cell grade is taken as the lithium replenishment effect of the battery.

10. The method according to claim 1, characterized in that, The method further includes discharging the battery at a preset discharge rate; wherein the preset discharge rate is determined based on a preset coefficient and the rated capacity of the battery.

11. The method according to claim 1, characterized in that, After evaluating the lithium replenishment effect of the battery, the method further includes: The evaluation results of batteries with different lithium replenishment doses and the evaluation results of batteries without lithium replenishment are obtained from the same batch. The evaluation results of batteries without lithium replenishment are used as a benchmark to compare the evaluation results of batteries with different lithium replenishment doses, so as to generate the correspondence between lithium replenishment dose and lithium replenishment effect.

12. A device for detecting the lithium replenishment effect of a lithium-ion battery, characterized in that, include: The discharge measurement module is used to measure the open-circuit voltage of the battery during the discharge process of the battery under test, and to construct a curve of the change of open-circuit voltage with state of charge for the battery. The parameter extraction module is used to extract distortion characteristic parameters for the battery based on the curve segments in the change curve that are not higher than the state of charge threshold; wherein, the state of charge threshold is related to the disturbance of the open circuit voltage caused by the residual lithium metal introduced by the battery. An evaluation module is used to evaluate the lithium replenishment effect of the battery based on the distortion characteristic parameters.

13. A lithium-ion battery lithium replenishment effect detection system, characterized in that, It includes a state-of-charge detection device, an open-circuit voltage detection device, and a lithium-ion battery lithium replenishment effect detection device as described in claim 12.

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