Lithium plating layer monitoring method and device of reference electrode, electronic equipment and storage medium

Abstract

The invention discloses a lithium plating layer monitoring method and device of a reference electrode, electronic equipment and a storage medium. The lithium plating layer monitoring method of the reference electrode comprises the following steps: acquiring voltage data in a reference electrode preparation process and voltage data in a reference electrode shelving process under different lithium plating influence factors; establishing a reference electrode standard library according to the voltage data in the reference electrode preparation process and the voltage data in the reference electrode shelving process under different lithium plating influence factors; acquiring voltage monitoring data of the reference electrode being monitored; and comparing the voltage monitoring data with voltage data in a reference electrode standard library, and evaluating the reference electrode being monitored according to a comparison result. The method can determine whether the quality of the lithium plating layer of the reference electrode is good or not, and is simple to operate, high in recognition degree and low in cost.

Description

Technical Field

[0001] The invention relates to the technical field of reference electrodes, and in particular to a method, a device, an electronic device and a storage medium for monitoring a lithium plating layer of a reference electrode. Background Art

[0002] The use of reference electrode technology can obtain information on positive and negative potentials and guide the formulation of fast charging strategies. However, during use, the instability of the lithium plating layer in the reference electrode often leads to failure midway, thus affecting the test results. Therefore, it is particularly important to identify the quality of the lithium plating layer in the reference electrode formed in the early stage.

[0003] In the prior art, it is generally necessary to disassemble the battery and take out the reference electrode to perform morphological characterization of the quality of the lithium plating layer. The operation is complicated and destroys the original structure of the battery, making it impossible to reuse it, and the evaluation cost is high. Summary of the invention

[0004] The invention provides a method, device, electronic equipment and storage medium for monitoring a lithium plating layer of a reference electrode, which are used to determine whether the quality of the lithium plating layer of the reference electrode is good with simple operation and low cost.

[0005] According to one aspect of the present invention, a method for monitoring a lithium plating layer of a reference electrode is provided, and the method for monitoring a lithium plating layer of a reference electrode comprises: Obtain voltage data during the reference electrode preparation process and voltage data during the reference electrode storage process under different lithium plating influencing factors; According to the voltage data of the reference electrode preparation process and the voltage data of the reference electrode storage process under different lithium plating influencing factors, a reference electrode standard library is established; Acquire voltage monitoring data of the reference electrode being monitored; The voltage monitoring data is compared with the voltage data in the reference electrode standard library, and the reference electrode being monitored is evaluated based on the comparison results.

[0006] Furthermore, factors affecting lithium plating include excessive charging current during the lithium plating process of the reference electrode, rough surface of the reference electrode, and impurities in the reference electrode electrolyte.

[0007] Furthermore, according to the voltage data of the reference electrode during the preparation process and the voltage data of the reference electrode during the storage process under different lithium plating influencing factors, a reference electrode standard library is established, including: Determine the corresponding relationship between the reference voltage and time during the preparation process and the corresponding relationship between the reference voltage and time during the shelving process according to the voltage data during the preparation process of the reference electrode and the voltage data during the shelving process of the reference electrode; A reference electrode standard library is established according to the corresponding relationship between the reference voltage and time during the preparation process and the corresponding relationship between the reference voltage and time during the storage process.

[0008] Furthermore, a reference electrode standard library is established according to the corresponding relationship between the reference voltage and time during the preparation process and the corresponding relationship between the reference voltage and time during the storage process, including: The lithium plating nucleation potential is determined according to the corresponding relationship between the reference voltage and time during the preparation process; The average depolarization rate is determined according to the corresponding relationship between the reference voltage and time during the shelf process; A reference electrode standard library was established based on the lithium plating nucleation potential and the average depolarization rate.

[0009] Further, according to the voltage data of the reference electrode during the preparation process and the voltage data of the reference electrode during the storage process, the corresponding relationship between the reference voltage and time during the preparation process and the corresponding relationship between the reference voltage and time during the storage process are determined, and then the method further includes: According to the corresponding relationship between the reference voltage and time in the preparation process of the reference electrode, the corresponding relationship between the first-order potential and time in the preparation process is determined; According to the corresponding relationship between the reference voltage and time during the shelving process of the reference electrode, the corresponding relationship between the first-order potential and time during the shelving process is determined.

[0010] Furthermore, the depolarization rate is determined based on the reference voltage data at the end of the preparation, the reference voltage data at the beginning of the preparation, and the preparation time.

[0011] According to another aspect of the present invention, a lithium plating layer monitoring device for a reference electrode is provided, and the lithium plating layer monitoring device for a reference electrode comprises: A voltage data acquisition module is used to acquire voltage data during the preparation process of the reference electrode and voltage data during the storage process of the reference electrode under different lithium plating influencing factors; A standard library establishment module is used to establish a reference electrode standard library according to the voltage data of the reference electrode during the preparation process and the voltage data of the reference electrode during the storage process under different lithium plating influencing factors; A voltage monitoring data acquisition module is used to acquire voltage monitoring data of a reference electrode being monitored; The evaluation module is used to compare the voltage monitoring data with the voltage data in the reference electrode standard library, and evaluate the reference electrode being monitored based on the comparison result.

[0012] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the lithium plating layer monitoring method of the reference electrode described in any embodiment of the present invention.

[0013] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the method for monitoring the lithium plating layer of a reference electrode described in any embodiment of the present invention when executed.

[0014] According to another aspect of the present invention, a computer program product is provided, the computer program product comprising a computer program, and the computer program, when executed by a processor, implements the method for monitoring the lithium plating layer of a reference electrode according to any embodiment of the present invention.

[0015] The lithium plating layer monitoring method of the reference electrode provided in the embodiment of the present invention obtains the voltage data of the reference electrode preparation process and the voltage data of the reference electrode during the storage process under different lithium plating influencing factors, and establishes a reference electrode standard library according to the voltage data of the reference electrode preparation process and the voltage data of the reference electrode during the storage process under different lithium plating influencing factors, and then obtains the voltage monitoring data of the reference electrode being monitored, compares the voltage monitoring data with the voltage data in the reference electrode standard library, and evaluates the reference electrode being monitored according to the comparison result. Compared with the prior art that requires disassembling the battery and taking out the reference electrode to perform morphological characterization of the quality of the lithium plating layer, the embodiment of the present invention can determine whether the quality of the lithium plating layer of the reference electrode is good by only obtaining the voltage monitoring data of the reference electrode being monitored and comparing the voltage monitoring data with the voltage data in the reference electrode standard library. The operation is simple, the recognition is high and the cost is low.

[0016] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 is a flow chart of a method for monitoring a lithium plating layer of a reference electrode provided in an embodiment of the present invention; Figure 2 is a schematic diagram of a lithium plating layer of a reference electrode under standard lithium plating parameters provided by an embodiment of the present invention; Figure 3 is a schematic diagram of a lithium plating layer of a reference electrode when a charging current is too large according to an embodiment of the present invention; Figure 4 is a schematic diagram of a lithium plating layer of a reference electrode when the roughness is too large according to an embodiment of the present invention; Figure 5 is a schematic diagram of a lithium plating layer of a reference electrode when the impurity concentration of an electrolyte is high according to an embodiment of the present invention; Figure 6 is a schematic diagram of the corresponding relationship between a positive electrode reference voltage and time provided according to an embodiment of the present invention; Figure 7 is a schematic diagram of a corresponding relationship between a negative electrode reference voltage and time provided according to an embodiment of the present invention; Figure 8 is a schematic diagram of the corresponding relationship between the positive electrode reference voltage and time during a standby process provided according to an embodiment of the present invention; Fig. 9 is a schematic diagram of the corresponding relationship between the negative electrode reference voltage and time during a standby process provided by an embodiment of the present invention; Fig.10 is a schematic diagram of the corresponding relationship between the first-order potential of a positive electrode and time according to an embodiment of the present invention; Fig.11 is a schematic diagram of the corresponding relationship between the first-order potential of a negative electrode and time according to an embodiment of the present invention; Fig.12 is a schematic diagram of the corresponding relationship between the first-order potential of the positive electrode and time during a shelf process provided by an embodiment of the present invention; Fig.13 is a schematic diagram of the corresponding relationship between the first-order potential of the negative electrode and time during a shelf process provided by an embodiment of the present invention; Fig.14 is a structural schematic diagram of a lithium plating layer monitoring device of a reference electrode provided in an embodiment of the present invention; Fig.15 A schematic diagram of the structure of an electronic device that can be used to implement an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0020] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0021] The embodiment of the present invention provides a method for monitoring the lithium plating layer of a reference electrode. Figure 1 is a flow chart of a lithium plating layer monitoring method of a reference electrode provided according to an embodiment of the present invention, with reference to Figure 1 , the lithium plating layer monitoring method of the reference electrode includes: S110, obtaining voltage data of the reference electrode during preparation and voltage data of the reference electrode during storage under different lithium plating influencing factors.

[0022] Among them, the factors affecting lithium plating include the charging current during the lithium plating process of the reference electrode, the surface roughness of the reference electrode, and the impurity concentration of the reference electrode electrolyte. For better explanation, it is defined here that when the charging current is ≥100μA, it is considered to be too large, and when the charging current is ≥10μA and <50μA, it is considered to be appropriate. In the following embodiments, when the charging current is selected as 200μA, it is considered to be too large. When the charging current of the standard group is selected as 20μA, it is considered to be appropriate. In order to avoid the cross-influence of multiple factors, the charging current is set to be appropriate when the roughness is large or the impurity concentration of the electrolyte is high. The charging current in the above two cases in the embodiment is selected as 20μA.

[0023] Specifically, Figure 2 is a schematic diagram of a lithium plating layer of a reference electrode under a standard lithium plating parameter provided in an embodiment of the present invention, with reference to Figure 2, the voltage data of the reference electrode preparation process can be obtained under the conditions of standard charging current, normal roughness and normal electrolyte concentration. For example, the reference electrode is formed by placing a smooth copper wire between the positive electrode sheet and the negative electrode sheet, and performing in-situ lithium plating on the positive electrode and the negative electrode. Figure 2 The lithium-plated structure shown in the figure has a uniform and flat surface of the lithium-plated layer without obvious defects, wherein the diameter of the copper wire is 40μm, the lithium-plated thickness is about 15μm, and 15μm is the thickness of the lithium-plated layer after reading from the device and deducting the diameter of the copper wire. The specific method is as follows: First, the three-electrode battery cell after capacity division is adjusted to a 50% state of charge with a constant current of 0.33C, wherein the charge and discharge ratio of the three-electrode battery cell marked by 0.33C is 0.33. Then, a charging current of 20μA is used to plate lithium on the reference electrode through the positive electrode for 2h, and then it is left for 6h, and the reference electrode is plated with lithium through the negative electrode with the same current and the same time, and the voltage data is obtained in real time during the preparation of the reference electrode, and then it is left for 6h.

[0024] Figure 3 is a schematic diagram of a lithium plating layer of a reference electrode when a charging current is too large according to an embodiment of the present invention, Figure 3 , it is also possible to obtain voltage data during the preparation of the reference electrode under the conditions of excessive charging current, normal roughness, and normal electrolyte impurity concentration. For example, at this time, the reference electrode is formed by placing a smooth copper wire between the positive electrode sheet and the negative electrode sheet, and performing in-situ lithium plating on the positive and negative electrodes. Figure 3 The lithium-plated structure shown in the figure has serious uneven deposition and block deposition on the surface of the lithium-plated layer. Among them, the copper wire diameter is 40μm, and the lithium plating thickness is about 30μm. 30μm is the thickness of the lithium-plated layer after reading from the device and deducting the copper wire diameter. Since the lithium plating is uniformly carried out according to time during the experiment, the greater the current, the thicker the lithium plating layer is at the same time. The specific method is as follows: First, the three-electrode battery cell after capacity division is adjusted to a 50% charge state with a constant current charge and discharge of 0.33C. Then, a charging current of 200μA is used to plate lithium on the reference electrode through the positive electrode for 2h, and then it is left for 6h, and the same current and the same time are used to plate lithium on the reference electrode through the negative electrode. The voltage data is obtained in real time during the preparation of the reference electrode, and then it is left for 6h.

[0025] Figure 4 is a schematic diagram of a lithium plating layer of a reference electrode when the roughness is too large according to an embodiment of the present invention, Figure 4 , it is also possible to obtain voltage data during the preparation of the reference electrode under the conditions of standard charging current, large roughness and normal electrolyte impurity concentration. For example, the reference electrode is formed by placing a copper wire with a rough surface and severe burrs between the positive electrode and the negative electrode, and performing in-situ lithium plating on the positive and negative electrodes. Figure 4The lithium-plated structure shown in the figure has defects of unplated lithium where there are burrs on the surface of the lithium-plated layer. Among them, the diameter of the copper wire is 40μm, and the thickness of the lithium plating is about 15μm. 15μm is the thickness of the lithium plating layer after reading from the device and deducting the diameter of the copper wire. The specific method is as follows: First, the three-electrode battery cell after capacity division is adjusted to a 50% charge state with a constant current charge and discharge of 0.33C. Then, a charging current of 20μA is used to plate lithium on the reference electrode through the positive electrode for 2h, and then it is left for 6h. The reference electrode is plated with lithium through the negative electrode with the same current and the same time. The voltage data is obtained in real time during the preparation of the reference electrode, and then it is left for 6h.

[0026] Figure 5 is a schematic diagram of a lithium plating layer of a reference electrode when the impurity concentration of an electrolyte is high according to an embodiment of the present invention, Figure 5 , it is also possible to obtain voltage data during the preparation of the reference electrode under the conditions of standard charging current, normal roughness and high impurity concentration in the electrolyte. For example, the reference electrode is prepared by placing a smooth copper wire between the positive electrode and the negative electrode. When the impurity elements in the electrolyte exceed the standard, for example, the impurity is Na2SO4, which accounts for less than 5% in the electrolyte. At this time, in-situ lithium plating is performed on the positive and negative electrodes to form a Figure 5 The lithium-plated structure shown in the figure has white contaminants on the surface of the lithium-plated layer, where the copper wire diameter is 40μm and the lithium-plated thickness is about 20μm, where 20μm is the thickness of the lithium-plated layer after reading from the device and deducting the copper wire diameter. The specific method is as follows: First, the three-electrode battery cell after capacity division is charged and discharged at a constant current of 0.33C to a charge state of 50%. Then, a charging current of 20μA is used to plate lithium on the reference electrode through the positive electrode for 2h, and then it is left for 6h, and the reference electrode is plated with lithium through the negative electrode with the same current and the same time. The voltage data is obtained in real time during the preparation of the reference electrode, and then it is left for 6h.

[0027] Exemplarily, the battery cell used in this embodiment is a lithium battery cell with a capacity of 2Ah and a size of 143mm*93mm with a three-electrode reference. The positive electrode material is a high-nickel ternary material, and the negative electrode material is a graphite system. However, the monitoring method provided in this embodiment is not limited to this battery system, and is also applicable to the quality judgment of the lithium plating layer of other battery systems.

[0028] S120. Establish a reference electrode standard library according to voltage data during the reference electrode preparation process and voltage data during the reference electrode storage process under different lithium plating influencing factors.

[0029] Specifically, the corresponding relationship between the reference voltage and time during the preparation process and the corresponding relationship between the reference voltage and time during the shelving process can be determined based on the voltage data during the reference electrode preparation process, and a reference electrode standard library can be established based on the corresponding relationship between the reference voltage and time during the preparation process and the corresponding relationship between the reference voltage and time during the shelving process.

[0030] S130, obtaining voltage monitoring data of the reference electrode being monitored.

[0031] The voltage monitoring data may be voltage data of a reference electrode in a monitoring state detected in real time.

[0032] S140, comparing the voltage monitoring data with the voltage data in the reference electrode standard library, and evaluating the reference electrode being monitored based on the comparison result.

[0033] Specifically, the voltage monitoring data of the reference electrode being monitored can be compared with the voltage data in the reference electrode standard library, and the reference electrode being monitored can be evaluated based on the comparison result. For example, if the voltage monitoring data of the reference electrode being monitored matches the voltage data under the standard charging current, normal roughness and normal electrolyte concentration in the reference electrode standard library, it means that the lithium plating layer of the reference electrode being monitored has good quality; if the voltage monitoring data of the reference electrode being monitored matches the voltage data under the reference electrode standard library with excessive charging current, normal roughness and normal electrolyte concentration, it means that the lithium plating layer of the reference electrode being monitored has poor quality. The quality of the lithium plating layer of the reference electrode being monitored is abnormal, and the cause of the abnormality is excessive charging current; if the voltage monitoring data of the reference electrode being monitored matches the voltage data under the standard charging current, large roughness and normal electrolyte impurity concentration in the reference electrode standard library, it means that the quality of the lithium plating layer of the reference electrode being monitored is abnormal, and the cause of the abnormality is the rough surface of the reference electrode; if the voltage monitoring data of the reference electrode being monitored matches the voltage data under the standard charging current, normal roughness and high electrolyte impurity concentration in the reference electrode standard library, it means that the quality of the lithium plating layer of the reference electrode being monitored is abnormal, and the cause of the abnormality is high electrolyte impurity concentration.

[0034] The lithium plating layer monitoring method of the reference electrode provided in the embodiment of the present invention obtains the voltage data of the reference electrode preparation process and the voltage data of the reference electrode during the storage process under different lithium plating influencing factors, and establishes a reference electrode standard library according to the voltage data of the reference electrode preparation process and the voltage data of the reference electrode during the storage process under different lithium plating influencing factors, and then obtains the voltage monitoring data of the reference electrode being monitored, compares the voltage monitoring data with the voltage data in the reference electrode standard library, and evaluates the reference electrode being monitored according to the comparison result. Compared with the prior art that requires disassembling the battery and taking out the reference electrode to perform morphological characterization of the quality of the lithium plating layer, the embodiment of the present invention can determine whether the quality of the lithium plating layer of the reference electrode is good by only obtaining the voltage monitoring data of the reference electrode being monitored and comparing the voltage monitoring data with the voltage data in the reference electrode standard library. The operation is simple, the recognition is high and the cost is low.

[0035] Furthermore, factors affecting lithium plating include the charging current during the lithium plating process of the reference electrode, the surface roughness of the reference electrode, and the impurity concentration of the reference electrode electrolyte.

[0036] Furthermore, according to the voltage data of the reference electrode during the preparation process and the voltage data of the reference electrode during the storage process under different lithium plating influencing factors, a reference electrode standard library is established, including: Determine the corresponding relationship between the reference voltage and time during the preparation process and the corresponding relationship between the reference voltage and time during the shelving process according to the voltage data during the preparation process of the reference electrode and the voltage data during the shelving process of the reference electrode; A reference electrode standard library is established according to the corresponding relationship between the reference voltage and time during the preparation process and the corresponding relationship between the reference voltage and time during the storage process.

[0037] Specifically, the corresponding relationship between the positive electrode reference voltage and time is determined according to the positive electrode voltage data during the lithium plating process of the reference electrode, and the corresponding relationship between the negative electrode reference voltage and time is determined according to the negative electrode voltage data during the lithium plating process of the reference electrode. For example, Figure 6 is a schematic diagram of the corresponding relationship between a positive electrode reference voltage and time provided according to an embodiment of the present invention, Figure 7 is a schematic diagram of the corresponding relationship between the negative electrode reference voltage and time provided according to an embodiment of the present invention, such as Figure 6 and Figure 7As shown in the figure, when the positive electrode and the negative electrode are plated with lithium, the voltage is: the voltage corresponding to the excessive charging current > the voltage corresponding to the larger roughness > the voltage corresponding to the normal lithium plating > the voltage corresponding to the higher electrolyte impurity concentration. The voltage magnitude relationship is the comparison of the reference electrode after the lithium plating is stable, where the time corresponding to the stability is about 500s, and the actual first 200s is the formation process of lithium crystal nuclei. It can be seen from the curve that the potential relationship of the crystal nucleus formation process is: the potential corresponding to the excessive charging current > the potential corresponding to the larger roughness > the potential corresponding to the normal lithium plating > the potential corresponding to the higher electrolyte impurity concentration. This is consistent with the above voltage relationship. The possible reason is that the initial deposition substrate is copper wire, which does not contain any lithium on the surface. Therefore, when depositing lithium on the copper surface, it is necessary to overcome the equilibrium potential of electrochemical lithium deposition on copper, that is, it is necessary to provide sufficient electrochemical polarization, and polarization is a prerequisite for promoting the smooth progress of electrochemical energy. When polarization is satisfied, first, lithium nuclei are formed on the copper substrate (i.e., lithium nucleation), and then the nuclei grow. Different factors have different degrees of influence on the nucleation potential of the nuclei. The factor corresponding to the maximum nucleation potential is excessive charging current. This is because the larger the charging current, the stronger the polarization, so the lithium deposition kinetics is strong and the nucleation potential is the largest; then normal lithium plating, because the charging current of normal lithium plating is smaller than that of excessive charging current, so the lithium deposition kinetics is relatively weak, and the nucleation potential is relatively small; secondly, the roughness is large, and the roughness is large because of its uneven surface. This unevenness will lead to additional lithium deposition impedance compared to normal lithium plating. The potential must be higher to deposit on copper, so the nucleation potential is higher than normal lithium plating; finally, the impurity group, when the impurity content is high, the impurities further dilute the lithium ion concentration in the electrolyte. Compared with normal lithium plating and large roughness, polarization can only occur when the lithium ion concentration near the copper wire is sufficient, so the lithium deposition kinetics is relatively weak, and the nucleation potential is also relatively small. Then, the positive electrode lithium plating nucleation potential is determined according to the corresponding relationship between the positive electrode reference voltage and time during the preparation process, and the positive electrode average depolarization rate is determined according to the corresponding relationship between the positive electrode reference voltage and time during the storage process.

[0038] According to the positive electrode voltage data of the reference electrode during the shelving process, the corresponding relationship between the positive electrode reference voltage and time during the shelving process is determined, and according to the negative electrode voltage data of the reference electrode during the shelving process, the corresponding relationship between the negative electrode reference voltage and time during the shelving process is determined. Exemplarily, Figure 8 is a schematic diagram of the corresponding relationship between the positive electrode reference voltage and time during a standby process provided according to an embodiment of the present invention, Fig. 9 is a schematic diagram of the corresponding relationship between the negative electrode reference voltage and time during a standby process according to an embodiment of the present invention, such as Figure 8 and Fig. 9As shown in the figure, in the standby stage after the reference electrode is lithium-plated by the positive and negative electrodes, the voltage reduction rate is as follows: the voltage reduction rate corresponding to the excessive charging current > the voltage reduction rate corresponding to the larger roughness > the voltage reduction rate corresponding to the higher electrolyte impurity concentration > the voltage reduction rate corresponding to the normal lithium plating. This is due to the difference in the stability of the lithium plating layer. The possible reasons are: when the lithium plating layer morphology is poor, its specific surface area is large, the contact area with the electrolyte becomes larger, the stability of the lithium plating layer becomes worse, and the rate of depolarization will become faster. The lithium plating layer formed by large current is relatively loose, the stability is the worst, and the voltage reduction rate is the fastest. The lithium plating layer with defects formed by large roughness has general stability and the voltage reduction rate is second. When the electrolyte impurity concentration is high, the surface lithium deposition morphology is better than that of large charging current and large roughness, and the voltage reduction rate is slightly lower. Normal lithium plating has a good surface flatness and no defects, so the voltage reduction rate is the smallest.

[0039] Furthermore, a reference electrode standard library is established according to the corresponding relationship between the reference voltage and time during the preparation process and the corresponding relationship between the reference voltage and time during the storage process, including: The lithium plating nucleation potential is determined according to the corresponding relationship between the reference voltage and time during the preparation process; The average depolarization rate is determined according to the corresponding relationship between the reference voltage and time during the shelf process; A reference electrode standard library was established based on the lithium plating nucleation potential and the average depolarization rate.

[0040] Among them, the lithium plating nucleation potential includes the positive electrode lithium plating nucleation potential and the negative electrode lithium plating nucleation potential, among which the positive electrode lithium plating nucleation potential can be understood as Figure 6 The peak voltage in the negative electrode, the lithium plating nucleation potential can be understood as Figure 7 The peak voltage in the curve. The metal deposition process includes nucleation and grain growth. Nucleation occurs first, that is, after a certain current or voltage is applied to the system, ions begin to aggregate to form nuclei. At this time, the potential corresponding to the process is the nucleation potential, that is, the peak potential of the curve. The average depolarization rate includes the average depolarization rate of the positive electrode and the average depolarization rate of the negative electrode. The average depolarization rate can be determined based on the reference voltage data at the end of the shelving, the reference voltage data at the beginning of the shelving, and the shelving time.

[0041] Further, according to the voltage data of the reference electrode during the preparation process and the voltage data of the reference electrode during the storage process, the corresponding relationship between the reference voltage and time during the preparation process and the corresponding relationship between the reference voltage and time during the storage process are determined, and then the method further includes: According to the corresponding relationship between the reference voltage and time in the preparation process of the reference electrode, the corresponding relationship between the first-order potential and time in the preparation process is determined; According to the corresponding relationship between the reference voltage and time during the shelving process of the reference electrode, the corresponding relationship between the first-order potential and time during the shelving process is determined.

[0042] Specifically, the voltage data of the reference electrode during the shelving process can be obtained under the conditions of standard charging current, normal roughness and normal electrolyte concentration, under the conditions of excessive charging current, normal roughness and normal electrolyte impurity concentration, under the conditions of standard charging current, large roughness and normal electrolyte impurity concentration, and under the conditions of standard charging current, normal roughness and high electrolyte impurity concentration. The voltage data includes positive electrode voltage data and negative electrode voltage data.

[0043] According to the corresponding relationship between the reference voltage and time of the positive electrode during the preparation of the reference electrode, the corresponding relationship between the first-order potential and time of the positive electrode during the preparation process is determined, and according to the corresponding relationship between the reference voltage and time of the negative electrode during the preparation of the reference electrode, the corresponding relationship between the first-order potential and time of the negative electrode during the preparation process is determined. Exemplarily, Fig.10 is a schematic diagram of the corresponding relationship between the first-order potential of a positive electrode and time according to an embodiment of the present invention, such as Fig.10 As shown, the first-order differential curve of positive electrode lithium plating can show the degree of change (intensity) of lithium deposition from polarization (nucleation) to nucleus growth, which corresponds to the fluctuation in the first 250s on the curve. After 250s, when lithium deposition stabilizes, the curve has almost no large fluctuations, that is, the fluctuation amplitude corresponding to the excessive charging current is greater than the fluctuation amplitude corresponding to the large roughness, the fluctuation amplitude corresponding to the high electrolyte impurity concentration, and the fluctuation amplitude corresponding to the normal lithium plating. The possible reason is that the three factors of excessive charging current, large roughness, and high electrolyte impurity concentration have a certain impact on the generation and growth of lithium nuclei, thus showing a phenomenon of greater fluctuations than normal lithium plating. This is consistent with the above. Figure 2-Figure 5 The conclusion of lithium deposition morphology is consistent with that of Fig.11 is a schematic diagram of the corresponding relationship between the first-order potential of a negative electrode and time according to an embodiment of the present invention, such as Fig.11As shown, the first-order differential curve of negative electrode lithium plating shows the degree of change (intensity) of lithium deposition from the occurrence of polarization (nucleation) to the growth of crystal nuclei, which corresponds to the fluctuation in the first 100 seconds on the curve. After 100 seconds, when the lithium deposition stabilizes, the curve has almost no large fluctuations, that is, the fluctuation amplitude corresponding to the excessive charging current is greater than the fluctuation amplitude corresponding to the large roughness, the fluctuation amplitude corresponding to the high electrolyte impurity concentration, and the fluctuation amplitude corresponding to normal lithium plating. The reasons for the above are the same as those for the difference in the fluctuation amplitude of lithium deposition in the above-mentioned positive electrode lithium plating process. It should be noted that since the positive electrode lithium plating is carried out first, a small amount of lithium can be deposited on the side of the copper wire of the reference electrode opposite to the negative electrode. Therefore, this size relationship does not Fig.10 It is obvious that, based on the above reasons, when the reference electrode surface is rough and has burrs, a small amount of lithium is plated on the negative electrode when lithium is plated on the positive electrode. At this time, the small amount of lithium plated on the negative electrode will fill the uneven base of part of the burrs, weakening the difference with other examples.

[0044] According to the corresponding relationship between the reference voltage of the positive electrode and time during the reference electrode shelving process, the corresponding relationship between the first-order potential of the positive electrode and time during the shelving process is determined, and according to the corresponding relationship between the reference voltage of the negative electrode and time during the reference electrode shelving process, the corresponding relationship between the first-order potential of the negative electrode and time during the shelving process is determined. Exemplarily, Fig.12 is a schematic diagram of the corresponding relationship between the first-order potential of the positive electrode and time during a shelf process provided by an embodiment of the present invention, Fig.13 1 is a schematic diagram of the corresponding relationship between the first-order potential of the negative electrode and time during a standby process according to an embodiment of the present invention. The first-order differential curve of the positive electrode lithium plating or negative electrode lithium plating standby process can show the degree of change (intensity) of the surface of the deposited lithium reference electrode tending to the equilibrium of the electrolyte. The fluctuation within the first 100s on the corresponding curve, and after 100s, the deposited lithium reference electrode reaches stability with the electrolyte, and the curve has almost no large fluctuations. Fig.12 and Fig.13 In the standby stage after the reference electrode is plated with lithium through the positive and negative electrodes, since the values ​​in the differential curve are mostly negative, after converting them into absolute values ​​for comparison, the voltage reduction rate is as follows: the fluctuation amplitude corresponding to the excessive charging current > the fluctuation amplitude corresponding to the large roughness > the fluctuation amplitude corresponding to the high electrolyte impurity concentration > the fluctuation amplitude corresponding to normal lithium plating.

[0045] Further, the average depolarization rate is determined based on the reference voltage data at the end of the shelf life, the reference voltage data at the beginning of the shelf life, and the shelf life time.

[0046] Specifically, the average depolarization rate of the positive electrode and the average depolarization rate of the negative electrode can be calculated respectively according to the average depolarization rate formula, wherein the calculation formula of the average depolarization rate is: ; in, is the average depolarization rate during the shelf process, in mV·h -1 ; V t is the reference voltage at the end of the shelf life, in mV; V0 is the reference voltage at the beginning of the shelf life, in mV; t is the duration of the entire shelf life, in h.

[0047] Specifically, the positive electrode lithium plating nucleation potential is determined according to the corresponding relationship between the positive electrode reference voltage and time during the preparation process, and the positive electrode average depolarization rate is determined according to the corresponding relationship between the positive electrode reference voltage and time during the shelving process; at the same time, the negative electrode lithium plating nucleation potential is determined according to the corresponding relationship between the negative electrode reference voltage and time during the preparation process, and the negative electrode average depolarization rate is determined according to the corresponding relationship between the negative electrode reference voltage and time during the shelving process, and a reference electrode standard library is established according to the positive electrode lithium plating nucleation potential, the negative electrode lithium plating nucleation potential, the positive electrode average depolarization rate and the negative electrode average depolarization rate.

[0048] Table 1 lists the characteristic values ​​of lithium plating under different factors affecting lithium plating. Among them, the characteristic values ​​of lithium plating include the positive electrode lithium plating nucleation potential, the negative electrode lithium plating nucleation potential, the positive electrode average depolarization rate and the negative electrode average depolarization rate.

[0049] Table 1 Lithium plating characteristic values ​​under different lithium plating influencing factors Positive electrode lithium plating nucleation potential / V <![CDATA[Average depolarization rate of the positive electrode / mV·h -1 > Negative electrode lithium plating nucleation potential / V <![CDATA[Average depolarization rate of the negative electrode / mV·h -1 > standard 3.9099~3.9238 1~2 0.2137~0.2235 1~2 High current problem ≥3.9450 10~20 ≥0.2419 10~20 Roughness Problem 3.9251~3.9389 5~6 0.2292~0.2390 5~6 High impurity concentration problem 3.9038~3.9177 3~4 0.2121~0.2220 3~4 After establishing a reference electrode standard library based on the positive electrode lithium plating nucleation potential, the negative electrode lithium plating nucleation potential, the positive electrode average depolarization rate and the negative electrode average depolarization rate, the voltage monitoring data of the reference electrode being monitored is obtained, and then the positive electrode lithium plating nucleation potential, the negative electrode lithium plating nucleation potential, the positive electrode average depolarization rate and the negative electrode average depolarization rate of the reference electrode being monitored are formed based on the voltage monitoring data of the reference electrode being monitored, and the positive electrode lithium plating nucleation potential, the negative electrode lithium plating nucleation potential, the positive electrode average depolarization rate and the negative electrode average depolarization rate of the reference electrode being monitored are compared with the data in the reference electrode standard library, thereby achieving an evaluation of the reference electrode being monitored.

[0050] The embodiment of the present invention provides a lithium plating layer monitoring device for a reference electrode. Fig.14 is a schematic diagram of a lithium plating layer monitoring device for a reference electrode according to an embodiment of the present invention, with reference to Fig.14 , the lithium plating layer monitoring device 200 of the reference electrode comprises: A voltage data acquisition module 210 is used to acquire voltage data of the reference electrode during preparation and voltage data of the reference electrode during storage under different lithium plating influencing factors; A standard library building module 220 is used to build a reference electrode standard library according to voltage data during the preparation process of the reference electrode and voltage data during the storage process of the reference electrode under different lithium plating influencing factors; A voltage monitoring data acquisition module 230 is used to acquire voltage monitoring data of a reference electrode being monitored; The evaluation module 240 is used to compare the voltage monitoring data with the voltage data in the reference electrode standard library, and evaluate the reference electrode being monitored according to the comparison result.

[0051] Furthermore, factors affecting lithium plating include excessive charging current during the lithium plating process of the reference electrode, rough surface of the reference electrode, and impurities in the reference electrode electrolyte.

[0052] Furthermore, the standard library building module 220 includes: A preparation process correspondence determination unit, used to determine the correspondence between the reference voltage and time in the preparation process and the correspondence between the reference voltage and time in the shelving process according to the voltage data in the reference electrode preparation process and the voltage data in the reference electrode shelving process; The standard library establishment unit is used to establish a reference electrode standard library according to the corresponding relationship between the reference voltage and time in the preparation process and the corresponding relationship between the reference voltage and time in the storage process.

[0053] Furthermore, the standard library building unit includes: A lithium plating nucleation potential determination subunit, used to determine the lithium plating nucleation potential according to the corresponding relationship between the reference voltage and time in the preparation process; A depolarization rate determination subunit, used for determining an average depolarization rate according to a corresponding relationship between a reference voltage and time during a shelf process; The standard library establishment subunit is used to establish a reference electrode standard library based on the lithium plating nucleation potential and the average depolarization rate.

[0054] Furthermore, the standard library building module 220 also includes: A first-order voltage data acquisition unit, for determining the corresponding relationship between the reference voltage and time in the preparation process and the corresponding relationship between the reference voltage and time in the shelving process according to the voltage data in the reference electrode preparation process and the voltage data in the reference electrode shelving process, and then determining the corresponding relationship between the first-order potential and time in the preparation process according to the corresponding relationship between the reference voltage and time in the reference electrode preparation process; The first-order shelf voltage data acquisition unit is used to determine the corresponding relationship between the first-order potential and time during the shelf process according to the corresponding relationship between the reference voltage and time during the shelf process of the reference electrode.

[0055] Further, the average depolarization rate is determined based on the reference voltage data at the end of the shelf life, the reference voltage data at the beginning of the shelf life, and the shelf life time.

[0056] The lithium plating layer monitoring device of the reference electrode provided in the embodiment of the present invention can execute the lithium plating layer monitoring method of the reference electrode provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0057] Fig.15 A schematic diagram of an electronic device that can be used to implement an embodiment of the present invention is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.) and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0058] like Fig.15 As shown, the electronic device 10 includes at least one processor 11, and a memory connected to the at least one processor 11, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., wherein the memory stores a computer program that can be executed by at least one processor, and the processor 11 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or the computer program loaded from the storage unit 18 to the random access memory (RAM) 13. In the RAM 13, various programs and data required for the operation of the electronic device 10 can also be stored. The processor 11, the ROM 12, and the RAM 13 are connected to each other through a bus 14. The input / output (I / O) interface 15 is also connected to the bus 14.

[0059] A number of components in the electronic device 10 are connected to the I / O interface 15, including: an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a disk, an optical disk, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0060] The processor 11 may be a variety of general and / or dedicated processing components with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The processor 11 performs the various methods and processes described above, such as a lithium plating layer monitoring method of a reference electrode.

[0061] In some embodiments, the lithium plating layer monitoring method of the reference electrode can be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as a storage unit 18. In some embodiments, part or all of the computer program can be loaded and / or installed on the electronic device 10 via the ROM 12 and / or the communication unit 19. When the computer program is loaded into the RAM 13 and executed by the processor 11, one or more steps of the lithium plating layer monitoring method of the reference electrode described above can be performed. Alternatively, in other embodiments, the processor 11 can be configured to perform the lithium plating layer monitoring method of the reference electrode by any other appropriate means (e.g., by means of firmware).

[0062] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0063] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when the computer program is executed by the processor, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer program may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0064] In the context of the present invention, a computer-readable storage medium may be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, device, or equipment. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or equipment, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0065] To provide interaction with a user, the systems and techniques described herein may be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

[0066] The systems and techniques described herein may be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0067] A computing system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The client and server relationship is generated by computer programs running on the corresponding computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services.

[0068] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0069] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for monitoring the lithium plating layer of a reference electrode, characterized in that: include: Obtain voltage data during the reference electrode preparation process and voltage data during the reference electrode storage process under different lithium plating influencing factors; According to the voltage data of the reference electrode preparation process and the voltage data of the reference electrode storage process under different lithium plating influencing factors, a reference electrode standard library is established; Acquire voltage monitoring data of the reference electrode being monitored; The voltage monitoring data is compared with the voltage data in the reference electrode standard library, and the reference electrode being monitored is evaluated based on the comparison result.

2. The method for monitoring the lithium plating layer of a reference electrode according to claim 1, wherein: The factors affecting lithium plating include the charging current during the lithium plating process of the reference electrode, the surface roughness of the reference electrode and the impurity concentration in the reference electrode electrolyte.

3. The lithium plating layer monitoring method of the reference electrode according to claim 1, characterized in that: According to the voltage data of the reference electrode preparation process and the voltage data of the reference electrode shelving process under different lithium plating influencing factors, a reference electrode standard library is established, including: Determine the corresponding relationship between the reference voltage and time during the preparation process and the corresponding relationship between the reference voltage and time during the shelving process according to the voltage data during the preparation process of the reference electrode and the voltage data during the shelving process of the reference electrode; A reference electrode standard library is established according to the corresponding relationship between the reference voltage and time in the preparation process and the corresponding relationship between the reference voltage and time in the storage process.

4. The method for monitoring the lithium plating layer of a reference electrode according to claim 3, wherein: A reference electrode standard library is established according to the corresponding relationship between the reference voltage and time in the preparation process and the corresponding relationship between the reference voltage and time in the storage process, including: Determining the lithium plating nucleation potential according to the corresponding relationship between the reference voltage and time in the preparation process; Determining an average depolarization rate according to the corresponding relationship between the reference voltage and time during the shelf process; A reference electrode standard library is established according to the lithium plating nucleation potential and the average depolarization rate.

5. The method for monitoring the lithium plating layer of a reference electrode according to claim 3, wherein: According to the voltage data in the reference electrode preparation process and the voltage data in the reference electrode shelving process, the corresponding relationship between the reference voltage and time in the preparation process and the corresponding relationship between the reference voltage and time in the shelving process are determined, and then the following is also included: According to the corresponding relationship between the reference voltage and time in the preparation process of the reference electrode, the corresponding relationship between the first-order potential and time in the preparation process is determined; According to the corresponding relationship between the reference voltage and time during the shelving process of the reference electrode, the corresponding relationship between the first-order potential and time during the shelving process is determined.

6. The method for monitoring the lithium plating layer of a reference electrode according to claim 4, wherein: The average depolarization rate is determined based on the reference voltage data at the end of the dwell, the reference voltage data at the beginning of the dwell, and the dwell time.

7. A lithium plating layer monitoring device for a reference electrode, characterized in that: include: A voltage data acquisition module is used to acquire voltage data during the reference electrode preparation process and voltage data during the reference electrode storage process under different lithium plating influencing factors; A standard library establishment module is used to establish a reference electrode standard library based on the voltage data during the reference electrode preparation process and the voltage data during the reference electrode storage process under different lithium plating influencing factors; A voltage monitoring data acquisition module is used to acquire voltage monitoring data of a reference electrode being monitored; The evaluation module is used to compare the voltage monitoring data with the voltage data in the reference electrode standard library, and evaluate the reference electrode being monitored according to the comparison result.

8. An electronic device, characterized in that: The electronic device comprises: at least one processor; and a memory communicatively connected to the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can perform the method for monitoring the lithium plating layer of the reference electrode according to any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the lithium plating layer monitoring method of a reference electrode according to any one of claims 1 to 6 when executed.

10. A computer program product, characterized in that The computer program product comprises a computer program, which, when executed by a processor, implements the method for monitoring the lithium plating layer of a reference electrode according to any one of claims 1 to 6.

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