A method and system for detecting the lithium plating safety performance of a lithium-ion battery

Abstract

The present invention discloses a method and system for detecting the lithium plating safety performance of a lithium-ion battery, which relates to the field of battery detection. First, the output power and output voltage of the battery are collected, and corresponding templates are constructed and correlated with each other. Through feature dimension reduction and equivalence comparison of the output power template, a representative reference output power template is extracted. Then, the real-time collected battery output power is compared with the reference template to determine the corresponding reference output voltage template. Finally, the real-time output voltage is compared based on the reference output voltage template, and whether the battery has a lithium plating phenomenon is judged according to the voltage difference characteristics. Through the above technical solutions, the present invention realizes efficient, accurate, and real-time detection of the lithium plating situation of the lithium-ion battery, and improves the safety performance of the battery.

Description

Technical Field

[0001] The present invention relates to the technical field of battery detection, and particularly to a method and system for detecting the lithium plating safety performance of a lithium-ion battery. Background Art

[0002] As a green energy source, lithium-ion batteries have been widely used in many fields such as electric vehicles, energy storage systems, and consumer electronics in recent years due to their advantages of high voltage, large energy density, and no memory effect. However, with the popularization of lithium-ion batteries, their safety problems have become increasingly prominent. Among them, the lithium plating phenomenon is one of the key factors leading to the decline of battery performance and even causing safety problems.

[0003] The lithium plating phenomenon mainly occurs during the battery charging process, especially under fast charging or low-temperature charging conditions. When the potential of the graphite negative electrode is lower than that of lithium, lithium ions accumulate on the surface of the negative electrode and cannot be embedded in time, forming lithium metal deposition, that is, lithium plating. Lithium plating will not only cause the battery capacity to decay rapidly and shorten the service life, but also the precipitated lithium metal may pierce the battery separator, causing the battery to short-circuit, and then generating serious safety problems such as overheating, fire, and even explosion.

[0004] Therefore, how to detect the lithium plating situation of lithium-ion batteries in a timely and accurate manner and evaluate their safety performance has become a technical problem that needs to be solved urgently by lithium-ion battery manufacturers and researchers. Most traditional lithium plating detection methods rely on disassembling the battery for internal observation, which is not only complex and inefficient in operation, but also unable to monitor the lithium plating situation of the battery in real time. Summary of the Invention

[0005] The purpose of the present invention is to provide a method and system for detecting the lithium plating safety performance of a lithium-ion battery that can timely detect the existence of lithium plating in the lithium-ion battery.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] A method for detecting the lithium plating safety performance of a lithium-ion battery includes:

[0008] Collect the output power and output voltage of the battery, construct an output power template of the battery based on the collected output power, construct an output voltage template of the battery based on the collected output voltage, and correlate the output power template and the output voltage template in an equivalent time-corresponding manner;

[0009] Perform feature dimensionality reduction on the output power template, determine the template feature data corresponding to the output power template, and classify the output power templates with matching template feature data once to obtain several first output power template groups;

[0010] Compare the output power templates in each first output power template group. Based on the preset equivalence determination criteria, classify the output power templates that meet the equivalence requirements again to obtain the second output power template group;

[0011] Perform an averaging calculation on the output power templates in the second output power template group to obtain an average output power template, and determine the reference degree of the average output power template based on the number of output power templates in the second output power template group. If the reference degree is greater than or equal to the preset value, then recognize the average output power template as the reference output power template;

[0012] Compare the real-time output power of the battery collected in real time with different reference output power templates, determine the matching reference output power template, and recognize the output voltage template corresponding to the reference output power template as the reference output voltage template;

[0013] Compare the real-time output voltage of the battery collected in real time based on the reference output voltage template, and determine whether lithium is precipitated from the battery based on the voltage difference characteristics.

[0014] In some embodiments disclosed by the present invention, the method for constructing an output power template includes:

[0015] Taking time as the horizontal coordinate and output power as the vertical coordinate, construct an output power coordinate system, and based on the collected output power, configure power coordinate points in the output power coordinate system. Connect the power coordinate points smoothly according to the progress direction of the time axis to obtain an output power curve, and record the output power curve as the output power template;

[0016] The method for constructing an output voltage template includes:

[0017] Taking time as the horizontal coordinate and output voltage as the vertical coordinate, construct an output voltage coordinate system, and based on the collected output voltage, configure voltage coordinate points in the output voltage coordinate system. Connect the voltage coordinate points smoothly according to the progress direction of the time axis to obtain an output voltage curve, and record the output voltage curve as the output voltage template.

[0018] In some embodiments disclosed by the present invention, the method for performing feature dimensionality reduction on the output power template includes:

[0019] Set an output power threshold array [v1, v2,..., vn], where v1 is the first preset output power threshold, v2 is the second preset output power threshold, vn is the nth preset output power threshold, and v1 < v2 <... < vn;

[0020] Randomly collect a preset number of output power points on the output power curve, and record the combination of the output power V0 corresponding to the output power points as the output power collection group;

[0021] Analyze the output power threshold interval to which each output power in the output power acquisition group belongs:

[0022] If v1 ≤ V0 < v2, then mark the corresponding V0 in the output power acquisition group as the preset characteristic parameter (v1 + v2) / 2;

[0023] If v2 ≤ V0 < v3, then mark the corresponding V0 in the output power acquisition group as the preset characteristic parameter (v2 + v3) / 2; ...;

[0025] If vn-1 ≤ V0 < vn, then mark the corresponding V0 in the output power acquisition group as the preset characteristic parameter (vn-1 + vn) / 2;

[0026] Combine the characteristic parameters corresponding to each output power in the output power acquisition group, and perform a size sorting during the combination process to form a characteristic parameter group.

[0027] In some embodiments disclosed by the present invention, the method for comparing the power templates in the first output power template group for equivalence includes:

[0028] Randomly combine the output power curves in the first output power template group in pairs to obtain a number of output power curve groups;

[0029] Align the output power curves in each output power curve group to coincide. The method for aligning to coincide includes dynamically translating one of them left and right, and after each dynamic translation, judging the coincidence situation between the output power curves. If the coincidence situation between the two meets the preset standard, it is determined that they are aligned to coincide at this time;

[0030] Calculate whether the output power curves after alignment to coincide meet the equivalence judgment conditions. If they meet, determine the corresponding output power curve group as the output power curve group to be concerned;

[0031] If there are duplicate output power curves between the output power curve groups to be concerned, then merge the duplicate output power curve groups to obtain a second output power template group.

[0032] In some embodiments disclosed by the present invention, the method for judging the coincidence situation between output power curves includes:

[0033] Conduct a trend analysis on the output power curves, and mark the curve segments with an upward trend and a downward trend that are greater than or equal to the preset time period;

[0034] Compare the marked curve segments between the output power curves. If the time period with consistent trends is greater than or equal to a preset value within a preset time period, it is determined that the coincidence situation between the output power curves meets the preset standard.

[0035] In some embodiments disclosed by the present invention, the method for determining the reference degree of the average output power template based on the number of output power templates in the second output power template group includes:

[0036] A template number threshold array [a1, a2,..., an] is set for the number of output power templates, where a1 is the first preset template number threshold, a2 is the second preset template number threshold, an is the nth preset template number threshold, and a1 < a2 <... < an. A reference degree array [g1, g2,..., gn] is set, where g1 is the first reference degree, g2 is the second reference degree, gn is the nth reference degree, and g1 < g2 <... < gn;

[0037] Judge the preset template number threshold interval to which the number A0 of output power templates in the second output power template group belongs:

[0038] If A0 < a1, it is determined that the reference degree of the average output power template is g1;

[0039] If a1 ≤ A0 < a2, it is determined that the reference degree of the average output power template is g2;

[0040] If a2 ≤ A0 < a3, it is determined that the reference degree of the average output power template is g3; ...;

[0042] If an-1 ≤ A0 < an, it is determined that the reference degree of the average output power template is gn.

[0043] In some embodiments disclosed by the present invention, the method for comparing the real-time output power of the battery collected in real time with different reference output power templates includes:

[0044] Substitute the real-time output power of the battery collected in real time into the reference output power curves corresponding to different reference output power templates, and calculate the vertical difference between the real-time output power and the reference output power curves at different time nodes;

[0045] Analyze the continuous characteristics of the vertical difference, determine the number of consecutive time nodes of the vertical difference greater than or equal to the preset value within the preset time period, and based on the number of consecutive time nodes and the cumulative amount of the vertical difference within the preset time period, determine the matching parameter between the real-time output power and the reference power template, and based on the matching parameter, determine the matching reference output power template.

[0046] In some embodiments disclosed by the present invention, a method for determining a compliance parameter between a real-time output power and a reference power template includes:

[0047] An accumulation threshold array [h1, h2,..., hn] is set, where h1 is the first preset accumulation threshold, h2 is the second preset accumulation threshold, hn is the nth preset accumulation threshold, and h1 < h2 <... < hn; an abnormal parameter array [s1, s2,..., sn] is set, where s1 is the first preset abnormal parameter, s2 is the second preset abnormal parameter, sn is the nth preset abnormal parameter, and s1 < s2 <... < sn; a continuous time node quantity threshold array [f1, f2,..., fn] is set, f1 is the first preset continuous time node quantity threshold, f2 is the second preset continuous time node quantity threshold, fn is the nth preset continuous time node quantity threshold, and f1 < f2 <... < fn; an abnormal parameter adjustment coefficient array [k1, k2,..., kn] is set, k1 is the first preset abnormal parameter adjustment coefficient, k2 is the second preset abnormal parameter adjustment coefficient, kn is the nth preset abnormal parameter adjustment coefficient, k1 < k2 <... < kn; and a maximum compliance parameter Ymax is set.

[0048] Judge the preset accumulation threshold interval to which the accumulation amount H0 of the vertical difference within a preset time period belongs:

[0049] If H0 < h1, then the first preset abnormal parameter s1 is determined as the reference abnormal parameter;

[0050] If h1 ≤ H0 < h2, then the second preset abnormal parameter s2 is determined as the reference abnormal parameter; ...;

[0052] If hn-1 ≤ H0 < hn, then the nth preset abnormal parameter sn is determined as the reference abnormal parameter.

[0053] Judge the preset continuous time node quantity threshold interval to which the number F0 of continuous time nodes belongs:

[0054] If F0 < f1, then the determined compliance parameter Y = Ymax - k1 * s1;

[0055] If f1 ≤ F0 < f2, then the determined compliance parameter Y = Ymax - k2 * s2; ...;

[0057] If fn-1 ≤ F0 < fn, then the determined compliance parameter Y = Ymax - kn * sn.

[0058] In some embodiments disclosed by the present invention, a lithium-ion battery lithium plating safety performance detection system is also disclosed, including:

[0059] The first module is used to collect the output power and output voltage of the battery, construct an output power template of the battery based on the collected output power, construct an output voltage template of the battery based on the collected output voltage, and correlate the output power template and the output voltage template in an equivalent time corresponding manner;

[0060] The second module is used to perform feature dimensionality reduction on the output power template, determine the template feature data corresponding to the output power template, and classify the output power templates with matching template feature data once to obtain several first output power template groups;

[0061] The third module is used to perform equivalence comparison on the output power templates in each first output power template group, and based on a preset equivalence determination standard, classify the output power templates that meet the equivalence requirements twice to obtain a second output power template group;

[0062] The fourth module performs an averaging calculation on the output power templates in the second output power template group to obtain an average output power template, and determines the reference degree of the average output power template based on the number of output power templates in the second output power template group. If the reference degree is greater than or equal to a preset value, the average output power template is determined as a reference output power template;

[0063] The fifth module is used to compare the real-time output power of the battery collected in real time with different reference output power templates, determine the matching reference output power template, and determine the output voltage template corresponding to the reference output power template as a reference output voltage template;

[0064] The sixth module is used to compare the real-time output voltage of the battery collected in real time based on the reference output voltage template, and determine whether lithium is precipitated from the battery based on the voltage difference feature.

[0065] The present invention discloses a method and system for detecting the lithium precipitation safety performance of a lithium-ion battery, which relates to the field of battery detection. First, the output power and output voltage of the battery are collected, corresponding templates are constructed and correlated with each other. By performing feature dimensionality reduction and equivalence comparison on the output power template, a representative reference output power template is extracted. Then, the real-time output power of the battery collected in real time is compared with the reference template to determine the matching reference output voltage template. Finally, the real-time output voltage is compared based on the reference output voltage template, and whether lithium precipitation occurs in the battery is judged according to the voltage difference feature. Through the above technical solutions, the present invention realizes efficient, accurate and real-time detection of the lithium precipitation situation of the lithium-ion battery, and improves the safety performance of the battery. Description of the Drawings

[0066] Figure 1This is a method step diagram of a method for detecting the lithium plating safety performance of a lithium-ion battery proposed by the present invention. Detailed implementation manners

[0067] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0068] The purpose of the present invention is to provide a method and system for detecting the lithium plating safety performance of a lithium-ion battery that can timely detect the lithium plating situation in the lithium-ion battery.

[0069] To achieve the above purpose, the present invention adopts the following technical solutions:

[0070] Refer to Figure 1 , a method for detecting the lithium plating safety performance of a lithium-ion battery, including:

[0071] Step S100, collect the output power and output voltage of the battery, construct an output power template of the battery based on the collected output power, construct an output voltage template of the battery based on the collected output voltage, and correlate the output power template and the output voltage template in an equivalent time corresponding manner.

[0072] The output power and output voltage of the battery are important parameters reflecting its working state. By collecting these parameters, an output power template and an output voltage template of the battery can be constructed. These two templates are correlated in an equivalent time corresponding manner, which means that at each time point, there is a corresponding output power value and output voltage value. In this way, the working state of the battery can be comprehensively and accurately described through these two templates, providing basic data for subsequent lithium plating detection.

[0073] In some embodiments disclosed by the present invention, the method for constructing the output power template includes:

[0074] Step S101, with time as the horizontal coordinate and output power as the vertical coordinate, construct an output power coordinate system, and based on the collected output power, configure power coordinate points in the output power coordinate system, and smoothly connect the power coordinate points in the progress direction of the time axis to obtain an output power curve, and record the output power curve as the output power template.

[0075] The method for constructing the output voltage template includes:

[0076] Step S102: Taking time as the horizontal coordinate and output voltage as the vertical coordinate, construct an output voltage coordinate system. Based on the collected output voltage, configure voltage coordinate points in the output voltage coordinate system, and smoothly connect the voltage coordinate points in the direction of the time axis to obtain an output voltage curve, which is denoted as the output voltage template.

[0077] Step S200: Perform feature dimensionality reduction on the output power template, determine the template feature data corresponding to the output power template, and classify the output power templates with matching template feature data once to obtain several first output power template groups.

[0078] Since the output power template of the battery may contain a large amount of data, direct processing would be very complex. Therefore, it is necessary to perform feature dimensionality reduction on it to extract the most representative template feature data. The purpose of screening each output power template group is to classify the output power templates under the same working state of the battery. Through feature dimensionality reduction and classification, the data processing process can be simplified, the efficiency of subsequent steps can be improved, and a foundation for subsequent equivalence analysis can be laid.

[0079] In some embodiments disclosed by the present invention, the method for performing feature dimensionality reduction on the output power template includes:

[0080] Step S201: Set an output power threshold array [v1, v2,..., vn], where v1 is the first preset output power threshold, v2 is the second preset output power threshold, vn is the nth preset output power threshold, and v1 < v2 <... < vn.

[0081] Step S202: Randomly collect a preset number of output power points on the output power curve, and denote the combination of the output power V0 corresponding to the output power points as the output power collection group.

[0082] Step S203: Analyze the output power threshold interval to which each output power in the output power collection group belongs.

[0083] If v1 ≤ V0 < v2, then mark the corresponding V0 in the output power collection group with the preset characteristic parameter (v1 + v2) / 2.

[0084] If v2 ≤ V0 < v3, then mark the corresponding V0 in the output power collection group with the preset characteristic parameter (v2 + v3) / 2.

[0085] ...

[0086] If vn - 1 ≤ V0 < vn, then mark the corresponding V0 in the output power collection group with the preset characteristic parameter (vn - 1 + vn) / 2.

[0087] Step S204: Combine the characteristic parameters corresponding to each output power in the output power acquisition group, and perform size sorting during the combination process to form a characteristic parameter group.

[0088] Step S300: Perform equivalence comparison on the output power templates in each first output power template group. Based on the preset equivalence determination criteria, classify the output power templates that meet the equivalence requirements for a second time to obtain a second output power template group.

[0089] Based on the first output power template group, it is necessary to further screen out more representative output power templates. This is achieved through equivalence comparison, that is, comparing the similarity between different templates and selecting the eligible templates according to the preset equivalence determination criteria. Each output power template in each second output power template group is equivalent, and they jointly represent a specific working state of the battery. Through equivalence analysis, templates with similar output power characteristics can be classified into one category to form a second output power template group. In this way, output power templates that can more accurately reflect different working states of the battery are obtained.

[0090] In some embodiments disclosed in the present invention, the method for performing equivalence comparison on the power templates in the first output power template group includes:

[0091] Step S301: Randomly combine the output power curves in the first output power template group in pairs to obtain several output power curve groups.

[0092] Step S302: Align the output power curves in each output power curve group to coincide. The method of coincident alignment includes dynamically translating one of them left and right, and after each dynamic translation, judge the coincidence status between the output power curves. If the coincidence status between the two meets the preset standard, it is determined that the two are aligned in coincidence at this time.

[0093] Step S303: Calculate whether the output power curves after coincident alignment meet the equivalence judgment conditions. If they meet, the corresponding output power curve group is determined as the output power curve group to be concerned.

[0094] Step S304: If there are duplicate output power curves between the output power curve groups to be concerned, merge the duplicate output power curve groups to obtain a second output power template group.

[0095] In some embodiments disclosed in the present invention, the method for judging the coincidence status between output power curves includes:

[0096] Step S3021: Perform trend analysis on the output power curves, and mark the curve segments with an upward trend and a downward trend that are greater than or equal to the preset time period.

[0097] Step S3022, compare the marked curve segments between the output power curves. If the time period with consistent trends is greater than or equal to a preset value within a preset time period, it is determined that the coincidence situation between the output power curves meets the preset standard.

[0098] Step S400, perform an averaging calculation on the output power templates in the second output power template group to obtain an average output power template, and determine the reference degree of the average output power template based on the number of output power templates in the second output power template group. If the reference degree is greater than or equal to the preset value, it is determined that the average output power template is the reference output power template.

[0099] Each template in the second output power template group represents the battery under different working states. By performing an averaging calculation on these templates, an average output power template can be obtained, which represents the average output power of the battery under normal working conditions. At the same time, the reference degree of the average output power template can also be evaluated according to the number of templates in the second output power template group. If the reference degree is greater than or equal to the preset value, then it can be determined that this average output power template is reliable and can be used as a reference for subsequent detection. The purpose of this step is to obtain a reference output power template that can accurately reflect the normal working state of the battery.

[0100] In some embodiments disclosed in the present invention, the method for determining the reference degree of the average output power template based on the number of output power templates in the second output power template group includes:

[0101] Step S401, set a template number threshold array [a1, a2,..., an] for the number of output power templates, where a1 is the first preset template number threshold, a2 is the second preset template number threshold, an is the nth preset template number threshold, and a1 < a2 <... < an. Set a reference degree array [g1, g2,..., gn], where g1 is the first reference degree, g2 is the second reference degree, gn is the nth reference degree, and g1 < g2 <... < gn.

[0102] Step S402, determine the preset template number threshold interval to which the number A0 of output power templates in the second output power template group belongs:

[0103] If A0 < a1, it is determined that the reference degree of the average output power template is g1.

[0104] If a1 ≤ A0 < a2, it is determined that the reference degree of the average output power template is g2.

[0105] If a2 ≤ A0 < a3, it is determined that the reference degree of the average output power template is g3.

[0106] ...。

[0107] If \(a_{n - 1}\leq A_0\lt a_n\), then the reference degree of the mean output power template is determined as \(g_n\).

[0108] Step S500: Compare the real-time output power of the battery collected in real time with different reference output power templates, determine the matching reference output power template, and determine the output voltage template corresponding to the reference output power template as the reference output voltage template.

[0109] In the real-time detection stage, it is necessary to compare the real-time output power of the battery with the previously obtained reference output power templates. Through comparison, the reference output power template that most matches the real-time output power can be found, and the corresponding output voltage template is determined as the reference output voltage template. The purpose of this step is to find the reference output voltage under the current working state of the battery, providing a basis for subsequent judgment of whether the battery has lithium plating phenomenon. By comparing the real-time output power and the reference output power templates, the current working state of the battery can be determined, and the corresponding reference output voltage template can be found.

[0110] In some embodiments disclosed in the present invention, the method for comparing the real-time output power of the battery collected in real time with different reference output power templates includes:

[0111] Step S501: Substitute the real-time output power of the battery collected in real time into the reference output power curve corresponding to different reference output power templates, and calculate the vertical difference between the real-time output power and the reference output power curve at different time nodes;

[0112] Step S502: Analyze the continuous characteristics of the vertical difference, determine the number of consecutive time nodes of the vertical difference greater than or equal to the preset value within the preset time period, and based on the number of consecutive time nodes and the cumulative amount of the vertical difference within the preset time period, determine the matching parameter between the real-time output power and the reference power template, and based on the matching parameter, determine the matching reference output power template.

[0113] In some embodiments disclosed in the present invention, the method for determining the matching parameter between the real-time output power and the reference power template includes:

[0114] Step S5021, set an accumulation threshold array [h1, h2,..., hn], where h1 is the first preset accumulation threshold, h2 is the second preset accumulation threshold, hn is the nth preset accumulation threshold, and h1 < h2 <... < hn. Set an abnormal parameter array [s1, s2,..., sn], where s1 is the first preset abnormal parameter, s2 is the second preset abnormal parameter, sn is the nth preset abnormal parameter, and s1 < s2 <... < sn. Set a continuous time node quantity threshold array [f1, f2,..., fn], f1 is the first preset continuous time node quantity threshold, f2 is the second preset continuous time node quantity threshold, fn is the nth preset continuous time node quantity threshold, and f1 < f2 <... < fn. Set an abnormal parameter adjustment coefficient array [k1, k2,..., kn], k1 is the first preset abnormal parameter adjustment coefficient, k2 is the second preset abnormal parameter adjustment coefficient, kn is the nth preset abnormal parameter adjustment coefficient, k1 < k2 <... < kn. Set a maximum matching parameter Ymax.

[0115] Step S5022, determine the preset accumulation threshold interval to which the accumulation amount H0 of the vertical difference amount within the preset time period belongs:

[0116] If H0 < h1, then determine the first preset abnormal parameter s1 as the reference abnormal parameter.

[0117] If h1 ≤ H0 < h2, then determine the second preset abnormal parameter s2 as the reference abnormal parameter.

[0118] ...

[0119] If hn - 1 ≤ H0 < hn, then determine the nth preset abnormal parameter sn as the reference abnormal parameter.

[0120] Step S5023, determine the preset continuous time node quantity threshold interval to which the number F0 of continuous time nodes belongs:

[0121] If F0 < f1, then the determined matching parameter Y = Ymax - k1 * s1.

[0122] If f1 ≤ F0 < f2, then the determined matching parameter Y = Ymax - k2 * s2.

[0123] ...

[0124] If fn - 1 ≤ F0 < fn, then the determined matching parameter Y = Ymax - kn * sn.

[0125] Step S600, compare the real-time output voltage of the battery collected in real time with the reference output voltage template, and determine whether lithium is precipitated from the battery based on the voltage difference characteristics.

[0126] Finally, compare the real-time output voltage of the battery collected in real time with the reference output voltage template. By comparing the differences between the two, it is possible to determine whether there is a phenomenon of lithium deposition in the battery. If there is a significant difference between the real-time output voltage and the reference output voltage, then it can be considered that lithium deposition may have occurred in the battery. The principle of this step is based on the characteristic that the output voltage of the battery changes when lithium is deposited for detection. Through this method, the lithium deposition situation of the battery can be discovered in a timely and accurate manner, and corresponding measures can be taken to ensure the safe use of the battery. By comparing the real-time output voltage and the reference output voltage template, the lithium deposition phenomenon of the battery can be effectively detected, and corresponding safety measures can be taken in a timely manner.

[0127] In some embodiments disclosed by the present invention, there is also disclosed a lithium deposition safety performance detection system for a lithium-ion battery, including:

[0128] A first module, configured to collect the output power and output voltage of the battery, construct an output power template of the battery based on the collected output power, construct an output voltage template of the battery based on the collected output voltage, and correlate the output power template and the output voltage template in an equivalent time corresponding manner.

[0129] A second module, configured to perform feature dimensionality reduction on the output power template, determine the template feature data corresponding to the output power template, and perform a first classification on the output power templates with matching template feature data to obtain several first output power template groups.

[0130] A third module, configured to perform equivalence comparison on the output power templates in each first output power template group, and based on a preset equivalence determination standard, perform a second classification on the output power templates that meet the equivalence requirements to obtain a second output power template group.

[0131] A fourth module, configured to perform an averaging calculation on the output power templates in the second output power template group to obtain an average output power template, and determine the reference degree of the average output power template based on the number of output power templates in the second output power template group. If the reference degree is greater than or equal to a preset value, the average output power template is determined as the reference output power template.

[0132] A fifth module, configured to compare the real-time output power of the battery collected in real time with different reference output power templates, determine the matching reference output power template, and determine the output voltage template corresponding to the reference output power template as the reference output voltage template.

[0133] A sixth module, configured to compare the real-time output voltage of the battery collected in real time based on the reference output voltage template, and determine whether lithium is deposited in the battery based on the voltage difference characteristics.

[0134] The present invention discloses a method and system for detecting the lithium plating safety performance of a lithium-ion battery, which relates to the field of battery detection. First, the output power and output voltage of the battery are collected, and corresponding templates are constructed and correlated with each other. Through feature dimensionality reduction and equivalence comparison of the output power template, a representative reference output power template is extracted. Then, the real-time collected battery output power is compared with the reference template to determine the corresponding reference output voltage template. Finally, the real-time output voltage is compared based on the reference output voltage template, and whether there is a lithium plating phenomenon in the battery is judged according to the voltage difference characteristics. Through the above technical solutions, the present invention realizes efficient, accurate and real-time detection of the lithium plating situation of the lithium-ion battery, and improves the safety performance of the battery.

[0135] As mentioned above, the above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A method for detecting the safety performance of lithium ion battery lithium deposition, characterized in that: include: The output power and output voltage of the battery are collected, and an output power template of the battery is constructed based on the collected output power, and an output voltage template of the battery is constructed based on the collected output voltage, and the output power template and the output voltage template are mutually associated in a manner of equivalent time correspondence; Performing feature dimension reduction on the output power template, determining template feature data corresponding to the output power template, and classifying the output power templates that match the template feature data to obtain a plurality of first output power template groups; Performing an equivalence comparison on the output power templates in each first output power template group, and based on a preset equivalence recognition standard, performing a secondary classification on the output power templates that meet the equivalence requirements to obtain a second output power template group; The output power templates in the second output power template group are averaged to obtain a mean output power template, and based on the number of output power templates in the second output power template group, a reference degree of the mean output power template is determined, and if the reference degree is greater than or equal to a preset value, the mean output power template is identified as a reference output power template; Compare the real-time output power of the battery collected in real time with different reference output power templates, determine the matching reference output power template, and identify the output voltage template corresponding to the reference output power template as the reference output voltage template; The real-time output voltage of the battery collected in real time is compared based on the reference output voltage template, and based on the voltage difference characteristics, it is determined whether the battery has lithium precipitation; With time as the horizontal coordinate and output power as the vertical coordinate, an output power coordinate system is constructed, and based on the collected output power, power coordinate points are configured in the output power coordinate system, and the power coordinate points are smoothly connected according to the progress direction of the time axis to obtain an output power curve, and the output power curve is recorded as an output power template; Methods for constructing an output voltage template include: With time as the horizontal coordinate and output voltage as the vertical coordinate, an output voltage coordinate system is constructed, and based on the collected output voltage, voltage coordinate points are configured in the output voltage coordinate system, and the voltage coordinate points are smoothly connected according to the progress direction of the time axis to obtain an output voltage curve, and the output voltage curve is recorded as an output voltage template; An output power threshold array [v1, v2, ..., vn] is set, wherein v1 is a first preset output power threshold, v2 is a second preset output power threshold, vn is an nth preset output power threshold, and v1<v2<...vn; Randomly collect a preset number of output power points on the output power curve, and record the combination of output power V0 corresponding to the output power points as an output power collection group; Analyze the output power threshold range to which each output power in the output power collection group belongs: If v1≤V0<v2, the corresponding V0 in the output power acquisition group is marked as the preset characteristic parameter (v1+v2) / 2; If v2≤V0<v3, the corresponding V0 in the output power acquisition group is marked as the preset characteristic parameter (v2+v3) / 2; ...； If vn-1≤V0<vn, the corresponding V0 in the output power acquisition group is marked as the preset characteristic parameter (vn-1+vn) / 2; The characteristic parameters corresponding to each output power in the output power acquisition group are combined, and are sorted in size during the combination process to form a characteristic parameter group.

2. A lithium ion battery lithium deposition safety performance detection method according to claim 1, characterized in that: The method for performing equivalence comparison on power templates in the first output power template group includes: Randomly combining the output power curves in the first output power template group in pairs to obtain a plurality of output power curve groups; The output power curves in each output power curve group are overlapped and aligned. The overlapped alignment method includes dynamically translating one of the output power curves to the left and right, and after each dynamic translation, judging the overlap between the output power curves. If the overlap between the two curves meets the preset standard, it is determined that the two curves have completed the overlapped alignment. Calculate whether the output power curves after overlap and alignment meet the equivalence judgment condition. If so, identify the corresponding output power curve group as the output power curve group requiring attention. If it is to be noted that there are repeated output power curves between the output power curve groups, the repeated output power curve groups are merged to obtain a second output power template group.

3. A lithium ion battery lithium deposition safety performance detection method according to claim 2, characterized in that: Methods for determining the overlap between output power curves include: Perform trend analysis on the output power curve and mark the curve segments with rising and falling trends that are greater than or equal to a preset time period; By comparing the curve segments marked between the output power curves, if within the preset time period, the time period with the same trend is greater than or equal to the preset value, it is determined that the overlap between the output power curves meets the preset standard.

4. A lithium ion battery lithium deposition safety performance detection method according to claim 1, characterized in that: The method for determining the reference degree of the mean output power template based on the number of output power templates in the second output power template group includes: A template quantity threshold array [a1, a2, ..., an] is set for the number of output power templates, wherein a1 is the first preset template quantity threshold, a2 is the second preset template quantity threshold, an is the nth preset template quantity threshold, and a1<a2<...<an is set, and a reference degree array [g1, g2, ..., gn] is set, wherein g1 is the first reference degree, g2 is the second reference degree, gn is the nth reference degree, and g1<g2<...<gn is set; Determine the preset template quantity threshold interval to which the number A0 of the output power templates in the second output power template group belongs: If A0<a1, the reference degree of the mean output power template is determined to be g1; If a1≤A0<a2, the reference degree of the mean output power template is determined to be g2; If a2≤A0<a3, the reference degree of the mean output power template is determined to be g3; ...； If an-1≤A0<an, then the reference degree of the mean output power template is determined to be gn.

5. A lithium ion battery lithium deposition safety performance detection method according to claim 1, characterized in that: The method for comparing the real-time output power of the battery collected in real time with different reference output power templates includes: Substitute the real-time output power of the battery collected in real time into the reference output power curve corresponding to different reference output power templates, and calculate the vertical difference between the real-time output power corresponding to different time nodes and the reference output power curve; The continuous characteristics of the vertical difference are analyzed to determine the number of continuous time nodes of the vertical difference that is greater than or equal to the preset value within the preset time period, and based on the number of continuous time nodes and the accumulation of the vertical difference within the preset time period, the matching parameters of the real-time output power and the reference power template are determined, and based on the matching parameters, the matching reference output power template is determined.

6. A lithium ion battery lithium deposition safety performance detection method according to claim 5, characterized in that: The method for determining the matching parameters of the real-time output power and the reference power template includes: Set an accumulation threshold array [h1,h2,...,hn], where h1 is the first preset accumulation threshold, h2 is the second preset accumulation threshold, hn is the nth preset accumulation threshold, and h1<h2<...<hn, set an abnormal parameter array [s1,s2,...,sn], where s1 is the first preset abnormal parameter, s2 is the second preset abnormal parameter, sn is the nth preset abnormal parameter, and s1<s2<...<sn, set a continuous time node number threshold array [f1,f2 ,...,fn], f1 is the first preset continuous time node number threshold, f2 is the second preset continuous time node number threshold, fn is the nth preset continuous time node number threshold, and f1<f2<...<fn, an abnormal parameter adjustment coefficient array [k1,k2,...,kn] is set, k1 is the first preset abnormal parameter adjustment coefficient, k2 is the second preset abnormal parameter adjustment coefficient, kn is the nth preset abnormal parameter adjustment coefficient, k1<k2<...<kn, and a maximum matching parameter Ymax is set; Step S5022, determining the preset accumulation threshold interval to which the accumulation H0 of the vertical difference within the preset time period belongs: If H0<h1, the first preset abnormal parameter s1 is identified as the reference abnormal parameter; If h1≤H0<h2, the second preset abnormal parameter s2 is identified as the reference abnormal parameter; ...； If hn-1≤H0<hn, the preset abnormal parameter sn is identified as the reference abnormal parameter. Determine the preset continuous time node quantity threshold interval to which the continuous time node quantity F0 belongs: If F0<f1, then the determined corresponding parameter Y=Ymax-k1*s1; If f1≤F0<f2, then the determined corresponding parameter Y=Ymax-k2*s2; ...； If fn-1≤F0<fn, then the determined corresponding parameter Y=Ymax-kn*sn.

7. A lithium-ion battery lithium deposition safety performance detection system, characterized in that: A method for detecting the safety performance of lithium deposition in a lithium-ion battery according to any one of claims 1 to 6, comprising: The first module is used to collect the output power and output voltage of the battery, and construct an output power template of the battery based on the collected output power, and construct an output voltage template of the battery based on the collected output voltage, and correlate the output power template and the output voltage template with each other in a manner of equivalent time correspondence; The second module is used to perform feature dimension reduction on the output power template, determine the template feature data corresponding to the output power template, and classify the output power templates that match the template feature data to obtain a plurality of first output power template groups; The third module is used to perform an equivalence comparison on the output power templates in each first output power template group, and based on a preset equivalence recognition standard, perform a secondary classification on the output power templates that meet the equivalence requirements to obtain a second output power template group; The fourth module averages the output power templates in the second output power template group to obtain a mean output power template, and determines the reference degree of the mean output power template based on the number of output power templates in the second output power template group. If the reference degree is greater than or equal to a preset value, the mean output power template is identified as a reference output power template. The fifth module is used to compare the real-time output power of the battery collected in real time with different reference output power templates, determine the matching reference output power template, and identify the output voltage template corresponding to the reference output power template as the reference output voltage template; The sixth module is used to compare the real-time output voltage of the battery collected in real time based on the reference output voltage template, and determine whether the battery has lithium precipitation based on the voltage difference characteristics.

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