Method for detecting charging boundary of lithium battery, charging detection method and application thereof

Abstract

The invention provides a method for detecting the charging boundary of a lithium battery, a charging detection method and application thereof, and relates to the field of lithium batteries. The method for detecting the charging boundary of the lithium battery comprises the following steps: constructing a lithium battery simulation model; the lithium battery simulation model is used for representing the relationship between input parameters and output parameters, and the input parameters comprise the charging temperature, the charging current and the state of charge of the lithium battery; the output parameter comprises a cathode potential; determining a test charging current based on the preset cathode potential, the preset charging temperature, the preset state of charge and the lithium battery simulation model; the method comprises the following steps: charging a lithium battery at a preset charging temperature and a preset charge state by adopting a test charging current, detecting whether a lithium precipitation phenomenon exists in the charging process of the lithium battery, and correcting a preset negative electrode potential according to a detection result to obtain a threshold negative electrode potential. Therefore, the polarity potential of the lithium battery can be compensated, the lithium battery simulation model is high in lithium battery simulation accuracy, and the charging boundary of the lithium battery can be accurately detected.

Description

Technical Field

[0001] The present application relates to the field of electronic information technology, in particular to the field of lithium battery technology, and specifically to a method for detecting a charging boundary of a lithium battery, a charging detection method and applications thereof. Background Art

[0002] As the power source of electric vehicles, batteries are directly related to the range, charging time and efficiency of electric vehicles. In order to improve charging efficiency and user experience, the main measure currently taken is to increase the charging current during the charging process.

[0003] Common negative electrode materials for lithium batteries are mostly carbon materials, which have a low potential for lithium, and are very likely to cause lithium deposition during the charging process of the negative electrode of the lithium battery. Lithium deposition will not only reduce the performance of the lithium battery, significantly shorten the cycle life, and limit the fast charging capacity of the lithium battery, but in severe cases it may even cause catastrophic consequences such as combustion and explosion. Therefore, during the charging process of the lithium battery, it is of great significance to accurately detect the charging boundary of the lithium battery, so as to achieve both good charging effect and good safety. Summary of the invention

[0004] The present application provides a method for detecting the charging boundary of a lithium battery, a charging detection method and its application, thereby compensating for the polarity potential generated by the polarization of the lithium battery electrodes, significantly improving the prediction accuracy of the lithium battery simulation model for the lithium battery, and better detecting the charging boundary of the lithium battery.

[0005] The technical solution of this application is as follows:

[0006] According to a first aspect of the present application, a method for detecting a charging boundary of a lithium battery is provided, comprising: constructing a lithium battery simulation model; the lithium battery simulation model is used to represent the relationship between input parameters and output parameters, the input parameters including the charging temperature, charging current and state of charge of the lithium battery; the output parameters including the negative electrode potential; determining a test charging current based on a preset negative electrode potential, a preset charging temperature, a preset state of charge and the lithium battery simulation model; charging the lithium battery with the test charging current at the preset charging temperature and the preset state of charge, detecting whether there is lithium deposition in the lithium battery during the charging process, and correcting the preset negative electrode potential according to the detection result to obtain a threshold negative electrode potential.

[0007] According to the above technical means, when the preset negative electrode potential in the lithium battery simulation model is determined, the preset charging temperature and the preset state of charge are input into the lithium battery simulation model, and by controlling the output parameters (preset negative electrode potential) and some input parameters (preset charging temperature, preset state of charge), some input parameters (test charging current) can be determined; at the preset charging temperature and the preset state of charge, the lithium battery is charged with a test charging current corresponding to the preset negative electrode potential to detect whether there is lithium deposition in the lithium battery during the charging process, and the preset negative electrode potential is corrected according to the detection result to obtain the threshold negative electrode potential. In this way, the polarity potential generated by the polarization of the lithium battery electrode can be compensated, which significantly improves the prediction accuracy of the lithium battery simulation model for the lithium battery, and can better detect the charging boundary of the lithium battery.

[0008] In a possible implementation, the preset negative electrode potential is corrected according to the detection result, including: when the lithium battery is detected to have lithium deposition during charging, the preset negative electrode potential is increased by a predetermined step length to obtain a first negative electrode potential. The preset negative electrode potential in this solution is generally small, for example, it can be 0V, 0.01V, etc.

[0009] According to the above technical means, when lithium deposition is detected in a lithium battery during charging, it is proved that the preset negative electrode potential corresponding to the lithium battery simulation model is small, and the correspondence between the lithium battery simulation model and its corresponding preset negative electrode potential and the actual lithium battery and its corresponding lithium deposition potential is poor. The first negative electrode potential is obtained by increasing the preset negative electrode potential by a predetermined step size. In this way, the polarity potential generated by the polarization of the lithium battery electrode can be compensated, thereby improving the prediction accuracy of the lithium battery simulation model for the lithium battery.

[0010] In a possible implementation, the method further includes: determining a first charging current based on a first negative electrode potential, a preset charging temperature, a preset state of charge, and a lithium battery simulation model; charging the lithium battery with the first charging current at the preset charging temperature and the preset state of charge, and determining the first negative electrode potential as an upper limit negative electrode potential when it is detected that there is no lithium deposition in the lithium battery during the charging process, and using the upper limit negative electrode potential as a threshold negative electrode potential. That is, in two adjacent charging processes, when there is lithium deposition in the first charging process and there is no lithium deposition in the second charging process, the negative electrode potential in the second charging process is determined to be the upper limit negative electrode voltage corresponding to the lithium battery simulation model.

[0011] According to the above technical means, the lithium battery is charged with the first charging current corresponding to the first negative electrode potential, and whether lithium deposition occurs during the charging process is detected, until it is detected that there is no lithium deposition during the charging process of the lithium battery (that is, during the charging process, the lithium battery changes from the presence of lithium deposition to the absence of lithium deposition), proving that the first negative electrode potential is the upper limit negative electrode potential, and the upper limit negative electrode potential is used as the threshold negative electrode potential. In this way, the upper limit negative electrode potential can be gradually detected by the approximation method, and the lithium battery is charged with the charging current corresponding to the upper limit negative electrode potential. After charging, the lithium battery will not have lithium deposition but is close to the occurrence of lithium deposition.

[0012] In a possible implementation, the preset negative electrode potential is corrected according to the detection result, including: when it is detected that there is no lithium deposition phenomenon in the lithium battery during the charging process, the preset negative electrode potential is reduced by a predetermined step length to obtain a second negative electrode potential. The preset potential negative electrode in this solution is generally larger, for example, it can be 0.06V, 0.05V, etc.

[0013] According to the above technical means, when it is detected that there is no lithium deposition phenomenon in the lithium battery during the charging process, it is proved that the preset negative electrode potential corresponding to the lithium battery simulation model may be large. The first negative electrode potential is obtained by reducing the preset negative electrode potential by a predetermined step size. In this way, the polarity potential generated by the polarization of the lithium battery electrode can be compensated, and the preset negative electrode potential can be alleviated, which leads to poor prediction accuracy of the lithium battery by the lithium battery simulation model.

[0014] In a possible implementation, the method further includes: determining a second charging current based on a second negative electrode potential, a preset charging temperature, a preset state of charge, and a lithium battery simulation model; charging the lithium battery with the second charging current at the preset charging temperature and the preset state of charge, and determining the preset negative electrode potential adjacent to the second preset electrode before correction as the upper limit negative electrode potential when lithium deposition is detected during the charging process of the lithium battery, and using the upper limit negative electrode potential as the threshold negative electrode potential. That is, in two adjacent charging processes, if there is no lithium deposition in the previous charging process and there is lithium deposition in the next charging process, the negative electrode potential in the previous charging process is determined to be the upper limit negative electrode voltage corresponding to the lithium battery simulation model.

[0015] According to the above technical means, the lithium battery is charged with the second charging current corresponding to the second negative electrode potential, and whether lithium deposition occurs during the charging process is detected until the lithium battery is detected to have lithium deposition during the charging process (that is, during the charging process, the lithium battery changes from no lithium deposition to lithium deposition), proving that the preset negative electrode potential before correction adjacent to the second preset electrode is the upper limit negative electrode potential, and the upper limit negative electrode potential is used as the threshold negative electrode potential. In this way, the upper limit negative electrode potential can be gradually detected by the approximation method, and the lithium battery is charged with the charging current corresponding to the upper limit negative electrode potential. After charging, the lithium battery will not have lithium deposition but is close to the occurrence of lithium deposition.

[0016] In a possible implementation, the upper limit charging current is determined based on the upper limit negative electrode potential, a preset charging temperature, a preset state of charge, and a lithium battery simulation model.

[0017] According to the above technical means, when the upper limit negative electrode potential is determined, the preset charging temperature and the preset state of charge are input into the lithium battery simulation model, and the upper limit charging current (i.e., the maximum safe current) under the preset charging temperature and the preset state of charge can be obtained. In this way, in the process of charging the lithium battery, it is beneficial to take into account both good charging effect and good safety.

[0018] In a possible implementation, the threshold negative electrode potential is 0V-0.06V, and the predetermined step length is 0.002V-0.005V. The change mode of the predetermined step length can be adjusted according to different application scenarios and requirements. For example, the predetermined step length can be a linear change or a nonlinear change.

[0019] According to the above technical means, the predetermined step length is controlled within the above range, the value of the predetermined step length is moderate, there is a high correspondence between the corrected preset negative electrode potential and the upper limit negative electrode potential, and the time consumed to correct the preset negative electrode potential to the upper limit negative electrode potential is short.

[0020] In some possible implementations, detecting whether lithium deposition occurs during charging of a lithium battery includes: white matter is deposited on the negative electrode plate of the lithium battery, proving that lithium deposition occurs during charging of the lithium battery.

[0021] According to the second aspect of the present application, a charging detection method is provided, which includes: determining the current negative electrode potential based on a preset charging temperature, a preset state of charge, a charging current and a lithium battery simulation model; the lithium battery simulation model is used to represent the relationship between input parameters and output parameters, the input parameters include the charging temperature, charging current and state of charge of the lithium battery; the output parameters include the negative electrode potential; based on the difference between the current negative electrode potential and the preset negative electrode potential, the charging current is corrected, and the lithium battery is charged with the corrected charging current.

[0022] In a possible implementation, correcting the current charging current includes: when it is determined that the current negative electrode potential is less than a predetermined negative electrode potential, increasing the charging current, and determining a first upper limit charging current.

[0023] In a possible implementation, correcting the current charging current includes: when it is determined that the current negative electrode potential is greater than a predetermined negative electrode potential, reducing the charging current, and determining a second upper limit charging current.

[0024] In a possible implementation, the charging detection method further includes: when the current negative electrode potential is about to be or has been less than a predetermined negative electrode potential, the battery management system will issue a warning message.

[0025] In some embodiments, the preset charging temperature in the second aspect is the preset charging temperature in the first aspect, the preset state of charge in the second aspect is the preset state of charge in the first aspect, the charging current in the second aspect is the charging current corresponding to the threshold negative electrode potential in the first aspect, and the predetermined negative electrode potential in the second aspect is the threshold negative electrode potential in the first aspect. The charging current corresponding to the threshold negative electrode potential represents: when the threshold negative electrode potential is determined, the charging current obtained by inputting the preset charging temperature and the preset state of charge into the lithium battery simulation model.

[0026] According to a third aspect of the present application, there is provided a device for detecting a charging boundary of a lithium battery, comprising: a modeling module for constructing a lithium battery simulation model; the lithium battery simulation model is used to represent the relationship between input parameters and output parameters, the input parameters including the charging temperature, charging current and state of charge of the lithium battery; the output parameters including the negative electrode potential; a processing module for obtaining a test charging current based on a preset negative electrode potential, a preset charging temperature, a preset state of charge and the lithium battery simulation model; a detection module for detecting lithium plating generated after the lithium battery is charged with the test charging current; the processing module is also used to obtain a threshold negative electrode potential obtained after correcting the preset negative electrode potential according to the detection result.

[0027] According to the fourth aspect of the present application, a battery management system is provided, including: a management module, used to determine the current negative electrode potential based on a preset charging temperature, a preset state of charge, a charging current and a lithium battery simulation model; the lithium battery simulation model is used to represent the relationship between input parameters and output parameters, the input parameters include the charging temperature, charging current and state of charge of the lithium battery; the output parameters include the negative electrode potential; a control module, used to correct the charging current based on the difference between the current negative electrode potential and the preset negative electrode potential, and charge the lithium battery with the corrected charging current.

[0028] According to the fifth aspect of the present application, a readable storage medium is provided. When the computer execution instructions stored in the readable storage medium are executed by the processor of the device for detecting the charging boundary of the lithium battery, the medium is used to implement the method for detecting the charging boundary of the lithium battery as described in the above embodiment; when the computer execution instructions stored in the readable storage medium are executed by the processor of the vehicle, the medium is used to implement the steps of the charging detection method as described in the above embodiment.

[0029] According to a sixth aspect of the present application, a vehicle is provided, comprising: a processor; and a memory for storing instructions executable by the processor; wherein the processor is configured to execute instructions for implementing the steps of the charging detection method as described in the above embodiment.

[0030] Therefore, the above technical features of the present application have the following beneficial effects:

[0031] (1) When the preset negative electrode potential in the lithium battery simulation model is determined, the preset charging temperature and the preset state of charge are input into the lithium battery simulation model. By controlling the output parameters (preset negative electrode potential) and some input parameters (preset charging temperature, preset state of charge), some input parameters (test charging current) can be determined; at the preset charging temperature and the preset state of charge, the lithium battery is charged with the test charging current corresponding to the preset negative electrode potential to detect whether there is lithium deposition in the lithium battery during the charging process. The preset negative electrode potential is corrected according to the detection result to obtain the threshold negative electrode potential. In this way, the polarity potential generated by the polarization of the lithium battery electrode can be compensated, which significantly improves the prediction accuracy of the lithium battery simulation model for the lithium battery and can better detect the charging boundary of the lithium battery.

[0032] (2) The lithium battery is charged with a first charging current corresponding to the first negative electrode potential, and whether lithium deposition occurs during the charging process is detected, until it is detected that the lithium battery does not deposit lithium during the charging process, proving that the first negative electrode potential is the upper limit negative electrode potential, and the upper limit negative electrode potential is used as the threshold negative electrode potential. In other words, in two adjacent charging processes, when lithium deposition occurs in the first charging process and does not occur in the second charging process, the negative electrode potential in the second charging process is determined to be the upper limit negative electrode voltage corresponding to the lithium battery simulation model. In this way, the upper limit negative electrode potential can be gradually detected by the approximation method, and the lithium battery is charged with the charging current corresponding to the upper limit negative electrode potential. After charging, the lithium battery will not deposit lithium but is close to depositing lithium.

[0033] (3) The lithium battery is charged with a second charging current corresponding to the second negative electrode potential, and whether lithium deposition occurs during the charging process is detected until lithium deposition is detected during the charging process, proving that the preset negative electrode potential adjacent to the second preset electrode before correction is the upper limit negative electrode potential, and the upper limit negative electrode potential is used as the threshold negative electrode potential. In other words, in two adjacent charging processes, if there is no lithium deposition in the first charging process and there is lithium deposition in the second charging process, the negative electrode potential in the first charging process is determined to be the upper limit negative electrode voltage corresponding to the lithium battery simulation model.

[0034] (4) When the upper limit negative electrode potential is determined, the preset charging temperature and the preset state of charge are input into the lithium battery simulation model, and the upper limit charging current (i.e., the maximum safe current) under the preset charging temperature and the preset state of charge can be obtained. In this way, in the process of charging the lithium battery, both good charging effect and good safety can be taken into account.

[0035] It should be noted that the technical effects brought about by the second, third, fourth, fifth and sixth aspects can refer to the technical effects brought about by the corresponding implementation methods in the first aspect, and will not be repeated here. It should be understood that the above general description and the detailed description below are only exemplary and explanatory, and cannot limit the present application.

[0036] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the specification are used to explain the principles of the present application, and do not constitute an improper limitation on the present application.

[0038] Figure 1 is a block diagram of a battery energy storage system according to an exemplary embodiment;

[0039] Figure 2 is a flow chart of a method for detecting a charging boundary of a lithium battery according to an exemplary embodiment;

[0040] Figure 3 is a block diagram of a device for detecting a charging boundary of a lithium battery according to an exemplary embodiment;

[0041] Figure 4 is a flow chart of a charging detection method according to an exemplary embodiment;

[0042] Figure 5 is a block diagram of a battery management system according to an exemplary embodiment;

[0043] Figure 6 is a block diagram of a vehicle according to an exemplary embodiment. DETAILED DESCRIPTION

[0044] In the specification and claims of the present application, the terms "first", "second", etc. 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 interchangeable where appropriate, so that the embodiments of the present application described here can be implemented in an order other than those illustrated or described here. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims.

[0045] Electric vehicles are a new energy vehicle with advantages such as environmental protection, energy saving and low operating costs. Batteries play a vital role in electric vehicles. Batteries are the power source of electric vehicles and are directly related to the range, charging time and efficiency of electric vehicles.

[0046] In order to improve charging efficiency and user experience, the main measure currently taken is to increase the charging current during the charging process. Common lithium battery negative electrode materials are mostly carbon materials. For example, the negative electrode material of lithium batteries is graphite. + ) The working potential of the intercalation layer in graphite is relatively low (for example, it can be 0.065V-0.2V), which causes the negative electrode of the lithium battery to easily undergo lithium deposition during the charging process. The lithium deposition phenomenon will not only reduce the performance of the lithium battery, significantly shorten the cycle life, and limit the fast charging capacity of the lithium battery, but in severe cases it will even cause catastrophic consequences such as combustion and explosion. Therefore, during the charging process of the lithium battery, the charging boundary of the lithium battery should be clearly defined so that both good charging effect and good safety can be taken into account. From another perspective, if the charging boundary is not clear, it is easy to cause the lithium battery to be overcharged, resulting in lithium deposition at the negative electrode of the lithium battery, making the charging effect and safety of the lithium battery poor, and shortening the service life of the lithium battery. It is also easy to cause the lithium battery to be undercharged or the charging time to be long, resulting in poor charging effect of the lithium battery.

[0047] During the charge and discharge process of a lithium battery, the passage of current may cause the electrode potential to deviate from its equilibrium state, causing the electrode of the lithium battery to polarize. The lithium deposition potential of a lithium battery is usually greater than 0V (for example, 0.06V). In the process of using a lithium battery simulation model to detect the charging boundary of a lithium battery, the lithium deposition potential of the lithium battery simulation model is usually set to 0V, which results in poor correspondence between the lithium battery simulation model and its corresponding preset negative electrode potential and the actual lithium battery and its corresponding lithium deposition potential. The lithium battery simulation model has low accuracy in simulating lithium batteries, which is not conducive to accurately detecting the charging boundary of a lithium battery.

[0048] At present, the detection of the charging boundary of lithium batteries mainly includes the following schemes. In some schemes, a "three-electrode battery" system is prepared according to different lithium battery characteristics to monitor the negative electrode potential of the lithium battery. If the negative electrode potential does not exceed the lithium deposition potential of the lithium battery, the charging current is further increased. The existing problems are: (1) During the charging and discharging process of the lithium battery, the current passing through may cause the electrode potential of the lithium battery to deviate from its equilibrium state, and the electrode of the lithium battery is polarized. However, the above scheme usually sets the lithium deposition potential to 0V. When the negative electrode potential is greater than 0V, it is considered that the negative electrode of the lithium battery begins to deposit lithium, which will cause a large deviation between the detection result and the actual situation; (2) The "three-electrode battery" system needs to be prepared according to the characteristics of the lithium battery, and the negative electrode potential of the lithium battery needs to be monitored in real time, which seriously limits the application prospects of the scheme. In other schemes, a method for determining the safety boundary of battery charging is provided, and the determination method includes: obtaining a dynamically adjusted charging strategy; after charging the battery using the adjusted charging strategy, obtaining the voltage information of the battery in the static stage; based on the voltage information of the battery in the static stage, detecting whether the battery has lithium deposition during the charging process; and determining the safety boundary of the battery charging strategy based on the detection results. The problems are: (1) This scheme does not take into account that the electrodes of lithium batteries may be polarized, so the lithium deposition potential is set to 0 V. When the negative electrode potential is greater than 0 V, it is considered that the negative electrode of the lithium battery begins to deposit lithium, which will cause a large deviation between the test results and the actual situation; (2) This scheme charges the battery and detects lithium deposition through experiments. The cost of implementing this scheme is high and it is difficult to achieve industrialization.

[0049] From the above analysis, it can be seen that in the process of charging a lithium battery, if the charging boundary is not clear, it is easy to cause the lithium battery to be overcharged, resulting in lithium deposition at the negative electrode of the lithium battery, poor charging effect and safety of the lithium battery, and a short service life of the lithium battery. It is also easy to cause the lithium battery to be undercharged, resulting in poor charging effect of the lithium battery. Based on this, in order to improve the accuracy of detecting the charging boundary of a lithium battery, an embodiment of the present application provides a method for detecting the charging boundary of a lithium battery.

[0050] For ease of understanding, the method for detecting the charging boundary of a lithium battery and the charging detection method provided in the present application are specifically introduced below in conjunction with the accompanying drawings.

[0051] The embodiments of the present application provide a method for detecting a charging boundary of a lithium battery and a charging detection method, which can be applied to a battery energy storage system. Figure 1 FIG. 1 is a schematic diagram showing a structure of a battery energy storage system according to an exemplary embodiment. Figure 1As shown, the battery energy storage system 10 includes: a battery system (battery system, referred to as BS) 11, a power conversion system (power conversion system, referred to as PCS) 12, a battery management system (battery management system, referred to as BMS) 13, and a monitoring system 14. It should be noted that those skilled in the art can understand that Figure 1 The battery energy storage system shown in the figure does not constitute a limitation on the battery energy storage system. The battery energy storage system may include Figure 1 More or fewer components, or combinations of certain components, or different component arrangements may be shown. The battery energy storage system described above may be used in a vehicle.

[0052] The battery system 11 is the main carrier for the battery energy storage system 10 to store and release electric energy. The capacity and operating state of the battery system 11 are directly related to the energy conversion capability and safety and reliability of the battery energy storage system 10. The battery system 11 may include a lithium battery.

[0053] The power conversion system 12 is a key component for the battery energy storage system 10 to exchange energy with the outside world. It can connect the battery system 11 and the AC power grid 20. The AC power in the AC power grid 20 can charge the battery system.

[0054] The battery management system 13 can monitor various states of the battery system 11 (such as voltage, current, temperature, state of charge, health status, etc.), perform safety management on the charging and discharging process of the battery system 11 (such as preventing overcharging and over-discharging management), alarm and perform emergency protection processing on possible faults of the battery system 11, and optimize the operation of the battery system. The battery management system 13 can also monitor the status information in the power conversion system 12.

[0055] The monitoring system 14 may monitor status information of the power conversion system 12 and the battery management system 13 .

[0056] The embodiment of the present application provides a method for detecting the charging boundary of a lithium battery, referring to Figure 2 ,include:

[0057] S100: constructing a lithium battery simulation model; the lithium battery simulation model is used to represent the relationship between input parameters and output parameters, the input parameters include the charging temperature, charging current and state of charge of the lithium battery; the output parameters include the negative electrode potential.

[0058] In some embodiments, the lithium battery simulation model includes an internal resistance model (Rint model), a Thevenin model (Thevenin model), a second-order RC model and a PNGV model. For example, the lithium battery simulation model includes the Thevenin model, and the lithium battery simulation model includes open circuit voltage, ohmic internal resistance, polarization internal resistance and polarization capacitance. The polarization internal resistance and polarization capacitance can constitute the polarization voltage. The Thevenin model can not only simulate the external characteristics of the lithium battery well, but also has a moderate amount of simulation calculation and high practical application universality.

[0059] In some embodiments, the lithium battery includes a shell, a positive electrode sheet, a negative electrode sheet, and a connector, etc. Among them, the static voltage in the lithium battery is the open circuit voltage (the open circuit voltage can be identified by SOC-OCV curve test), and the internal resistance between the electrode sheet and the connector and the shell is the ohmic internal resistance (the ohmic internal resistance can be identified by HPPC test under different temperature conditions); during the charge and discharge process, the passage of current may cause the electrode potential to deviate from its equilibrium state, and the electrodes of the lithium battery are polarized, resulting in polarization resistance and polarization capacitance (polarization internal resistance and polarization capacitance can be identified by HPPC test under different temperature conditions).

[0060] S200: Determine a test charging current based on a preset negative electrode potential, a preset charging temperature, a preset state of charge, and a lithium battery simulation model.

[0061] In this step, when the preset negative electrode potential in the lithium battery simulation model is determined, the preset charging temperature and the preset state of charge are input into the lithium battery simulation model. By controlling the output parameters (preset negative electrode potential) and some input parameters (preset charging temperature, preset state of charge), some input parameters (test charging current) can be determined.

[0062] In some possible implementations, the preset negative electrode potential may be 0 V to 0.06 V. In some possible implementations, the preset charging temperature may be -20° C. to 55° C. In some possible implementations, the preset state of charge may be 0% to 100%.

[0063] S300: charging the lithium battery with a test charging current at a preset charging temperature and a preset charge state, detecting whether lithium deposition occurs in the lithium battery during the charging process, and correcting the preset negative electrode potential according to the detection result to obtain a threshold negative electrode potential.

[0064] In this step, the lithium battery is charged with a test charging current at a preset charging temperature and a preset state of charge, and whether the lithium battery has lithium deposition during the charging process is detected. The preset negative electrode potential is corrected according to the detection result to obtain a threshold negative electrode potential. In this way, the polarity potential generated by the polarization of the lithium battery electrode can be compensated, which significantly improves the prediction accuracy of the lithium battery simulation model for the lithium battery, and can better detect the charging boundary of the lithium battery. In some possible implementations, the threshold negative electrode potential in step S300 can be the result of a single correction of the preset negative electrode potential, or it can be the result of multiple corrections of the preset negative electrode potential. In other words, the threshold negative electrode potential can be the same as or different from the subsequent upper limit negative electrode potential.

[0065] In some embodiments, the lithium battery simulation model includes a prediction algorithm. For example, the prediction algorithm may include a Kalman filter algorithm, a neural network algorithm, and a fuzzy algorithm. Since it is difficult to obtain the initial value and errors are prone to occur in actual applications, and there may also be system errors, by setting a prediction algorithm, the influence of errors on the lithium battery simulation model can be alleviated, and the accuracy of the lithium battery simulation model in simulating lithium batteries can be improved. Specifically, the prediction algorithm can predict the positive and negative electrode potentials of the lithium battery based on the test charging current, the preset charging temperature, and the preset state of charge. At the same time, the correction parameters in the prediction algorithm can be adjusted dynamically in real time based on the terminal voltage feedback between the positive and negative electrodes of the lithium battery, thereby improving the prediction accuracy of the lithium battery simulation model for the lithium battery.

[0066] In the embodiments of the present application, the lithium deposition potential corresponding to the lithium battery represents: when the negative electrode potential of the lithium battery exceeds the lithium deposition potential, lithium deposition will occur at the negative electrode of the lithium battery. For example, when the lithium deposition potential corresponding to the lithium battery is 0.05V, when the negative electrode potential of the lithium battery is 0.06V, lithium deposition will occur at the negative electrode of the lithium battery.

[0067] In the embodiment of the present application, the correction of the preset negative electrode potential according to the detection result in step S300 mainly includes the following two schemes:

[0068] In some embodiments, the first correction scheme for correcting the preset negative electrode potential according to the detection results is: when it is detected that the lithium battery has lithium deposition during the charging process, it is proved that the preset negative electrode potential corresponding to the lithium battery simulation model is small, and the correspondence between the lithium battery simulation model and its corresponding preset negative electrode potential and the actual lithium battery and its corresponding lithium deposition potential is poor. The first negative electrode potential is obtained by increasing the preset negative electrode potential by a predetermined step length, so that the polarity potential generated by the polarization of the lithium battery electrode can be compensated, and the prediction accuracy of the lithium battery simulation model for the lithium battery can be improved. In addition, the preset potential negative electrode in this scheme is generally small, for example, it can be 0V, 0.01V, etc.

[0069] In some embodiments, the first correction scheme mentioned above may also include: determining a first charging current based on a first negative electrode potential, a preset charging temperature, a preset state of charge, and a lithium battery simulation model; charging the lithium battery with the first charging current at the preset charging temperature and the preset state of charge, and determining the first negative electrode potential as the upper limit negative electrode potential when it is detected that there is no lithium deposition phenomenon in the lithium battery during the charging process, and using the upper limit negative electrode potential as the threshold negative electrode potential.

[0070] When lithium deposition is detected in the lithium battery, it is proved that the value of the preset negative electrode potential corresponding to the lithium battery simulation model is small, so the preset negative electrode potential is increased by a predetermined step size, and the preset negative electrode potential will increase to the first negative electrode potential; when the first negative electrode potential is determined, the preset charging temperature and the preset state of charge are input into the lithium battery simulation model, and the first charging current corresponding to the preset charging temperature and the preset state of charge can be obtained. At the preset charging temperature and the preset state of charge, the lithium battery is charged with the first charging current corresponding to the first negative electrode potential. Then, whether lithium deposition occurs during the charging process is detected. At this moment, there are two detection results, one of which is that it is detected that there is no lithium deposition during the charging process of the lithium battery (that is, during the charging process, the lithium battery changes from the presence of lithium deposition to the absence of lithium deposition), proving that the first negative electrode potential is the upper limit negative electrode potential, and the upper limit negative electrode potential is used as the threshold negative electrode potential; the other is that it is detected that lithium deposition still occurs during the charging process of the lithium battery, and the first correction scheme is repeated, that is, by increasing the first negative electrode potential by one or more predetermined steps to obtain a corrected first negative electrode potential, until there is no lithium deposition after charging the lithium battery with the charging current corresponding to the corrected first negative electrode potential, proving that the corrected first negative electrode potential at this moment is the upper limit negative electrode potential, and the upper limit negative electrode potential is used as the threshold negative electrode potential.

[0071] In other words, in two adjacent charging processes, if lithium deposition occurs in the first charging process but not in the second charging process, the negative electrode potential in the second charging process is determined to be the upper limit negative electrode voltage corresponding to the lithium battery simulation model.

[0072] In some embodiments, the second correction scheme for correcting the preset negative electrode potential according to the detection results is: when it is detected that there is no lithium deposition phenomenon in the lithium battery during the charging process, it is proved that the preset negative electrode potential corresponding to the lithium battery simulation model is large, and the first negative electrode potential is obtained by reducing the preset negative electrode potential by a predetermined step length. In this way, the polarity potential generated by the polarization of the lithium battery electrode can be compensated, and the preset negative electrode potential can be too large, which leads to the poor prediction accuracy of the lithium battery simulation model for the lithium battery. In addition, the preset potential negative electrode in this scheme is generally large, for example, it can be 0.06V, 0.05V, etc.

[0073] In some embodiments, the above-mentioned second correction scheme may also include: determining a second charging current based on a second negative electrode potential, a preset charging temperature, a preset state of charge and a lithium battery simulation model; using the second charging current to charge the lithium battery at a preset charging temperature and a preset state of charge, and when lithium deposition is detected in the lithium battery during the charging process, determining the preset negative electrode potential before correction adjacent to the second preset electrode as the upper limit negative electrode potential, and using the upper limit negative electrode potential as the threshold negative electrode potential.

[0074] When it is detected that there is no lithium deposition in the lithium battery, the preset negative electrode potential is reduced by a predetermined step length, and the preset negative electrode potential is reduced to a second negative electrode potential; when the second negative electrode potential is determined, the preset charging temperature and the preset state of charge are input into the lithium battery simulation model, and a second charging current corresponding to the preset charging temperature and the preset state of charge can be obtained; at the preset charging temperature and the preset state of charge, the lithium battery is charged with the second charging current corresponding to the second negative electrode potential. Then, whether lithium deposition occurs during the charging process is detected. At this moment, there are two detection results. One is that the lithium deposition phenomenon is detected during the charging process of the lithium battery (that is, during the charging process, the lithium battery changes from no lithium deposition phenomenon to lithium deposition phenomenon), proving that the preset negative electrode potential before the second negative electrode potential increases is the upper limit negative electrode potential, and the upper limit negative electrode potential is used as the threshold negative electrode potential. The other is that the lithium battery is detected to have no lithium deposition phenomenon during the charging process, and the second correction scheme is repeated, that is, the second negative electrode potential is reduced by one or more predetermined steps to obtain the corrected second negative electrode potential, until the charging current corresponding to the corrected second negative electrode potential is used to charge the lithium battery. There is lithium deposition phenomenon, proving that the negative electrode potential before the increase adjacent to the corrected second negative electrode potential is the upper limit negative electrode potential, and the upper limit negative electrode potential is used as the threshold negative electrode potential. In this way, the polarity potential generated by the polarization of the lithium battery electrode can be compensated, and the preset negative electrode potential can be alleviated, which leads to the poor prediction accuracy of the lithium battery simulation model for the lithium battery.

[0075] In other words, in two adjacent charging processes, if there is no lithium deposition in the previous charging process and there is lithium deposition in the next charging process, the negative electrode potential in the previous charging process is determined to be the upper limit negative electrode voltage corresponding to the lithium battery simulation model.

[0076] In the embodiment of the present application, the upper limit negative electrode potential corresponding to the lithium battery simulation model represents that the lithium battery simulation model and its corresponding upper limit negative electrode potential have the highest correspondence with the actual lithium battery and its corresponding lithium deposition potential.

[0077] In some embodiments, detecting whether there is lithium deposition during the charging process of a lithium battery includes: white substance precipitates from the negative electrode plate of the lithium battery, proving that there is lithium deposition during the charging process of the lithium battery. Specifically, after the charging of the lithium battery is completed (i.e., the battery cell at this moment is a fully charged cell), the battery cell of the lithium battery after the cycle is disassembled, and the negative electrode plate of the lithium battery is analyzed. If white substance precipitates from the negative electrode plate of the lithium battery, the white substance is metallic lithium, which can prove that there is lithium deposition during the charging process of the lithium battery; if there is no white substance precipitated from the negative electrode plate of the lithium battery, it can prove that there is no lithium deposition during the charging process of the lithium battery.

[0078] In some embodiments, when the upper limit negative electrode potential is determined, the preset charging temperature and the preset state of charge are input into the lithium battery simulation model, and the upper limit charging current (i.e., the maximum safe current) under the preset charging temperature and the preset state of charge can be obtained. The upper limit charging current can refer to the maximum safe current corresponding to a specific charging temperature and a specific state of charge, or it can refer to a charging current table of maximum safe currents corresponding to multiple charging temperatures and multiple states of charge. In this way, in the process of charging the lithium battery, it is beneficial to take into account both good charging effect and good safety.

[0079] In some possible implementations, by determining a charging current table of maximum safe currents corresponding to multiple charging temperatures and multiple states of charge, a charging rate table of upper limit charging rates corresponding to multiple charging temperatures and multiple states of charge can also be obtained. Since the change in charging temperature may cause the internal resistance in the lithium battery to change, affecting the charging rate of the lithium battery, the above charging rate table can better realize the charging of the lithium battery.

[0080] In some embodiments, the process of determining the upper limit negative electrode potential is described in detail: by controlling the charging temperature to a certain charging temperature and the charge state to a certain charge state during the charging process, the upper limit negative electrode potential corresponding to the lithium battery simulation model is evaluated, which can include two adjustment processes.

[0081] For example, the first adjustment process is: inputting a preset negative electrode potential (for example, the preset negative electrode potential is 0V), a preset charging temperature (for example, the preset charging temperature is 0°C), and a preset state of charge (for example, the preset state of charge is 50%) into a lithium battery simulation model to determine a test charging current;

[0082] At a preset charging temperature and a preset state of charge, a test charging current is used to charge the lithium battery to detect whether there is lithium deposition in the lithium battery during the charging process, and a predetermined step size (for example, the predetermined step size is 0.005V) is added to the preset negative electrode potential to obtain a first negative electrode potential (for example, the first negative electrode potential is 0.005V); when the first negative electrode potential is determined, a preset charging temperature (for example, the preset charging temperature is 0°C) and a preset state of charge (for example, the preset state of charge is 50%) are input into the lithium battery simulation model to determine the first charging current; at a preset charging temperature and a preset state of charge, a test charging current is used to charge the lithium battery to detect whether there is lithium deposition in the lithium battery during the charging process;

[0083] If the lithium battery at this moment has lithium deposition, it proves that the above adjustment process needs to be repeated to increase the first negative electrode potential in order to obtain the threshold negative electrode potential corresponding to the lithium battery simulation model (for example, the upper limit negative electrode potential is 0.03V, and the above adjustment process needs to be repeated 5 times); if the lithium battery at this moment does not have lithium deposition, it proves that the first negative electrode potential is the upper limit negative electrode potential corresponding to the lithium battery simulation model (for example, the upper limit negative electrode potential is 0.005V), and the upper limit negative electrode potential is the threshold negative electrode potential corresponding to the simulated lithium battery model. When the upper limit negative electrode potential is determined, the preset charging temperature and the preset state of charge are input into the lithium battery simulation model to determine the upper limit charging current corresponding to the simulated lithium battery model, and then the upper limit charging rate corresponding to the simulated lithium battery model is obtained. Similarly, by increasing or decreasing the preset charging temperature and repeating the first adjustment process, the upper limit charging rate at multiple specific temperatures can be obtained.

[0084] For another example, the second adjustment process is: inputting a preset negative electrode potential (usually the preset negative electrode potential at this moment is relatively large, for example, the preset negative electrode potential is 0.06V), a preset charging temperature (for example, the preset charging temperature is 0°C), and a preset state of charge (for example, the preset state of charge is 50%) into the lithium battery simulation model to determine the test charging current;

[0085] At a preset charging temperature and a preset state of charge, a test charging current is used to charge the lithium battery to detect whether there is lithium deposition during the charging process of the lithium battery, and a preset step size (for example, a preset negative electrode potential of 0.06V) is reduced to obtain a second negative electrode potential (for example, the second negative electrode potential is 0.055V); when the second negative electrode potential is determined, the preset charging temperature and the preset state of charge are input into the lithium battery simulation model to determine the second charging current; at a preset charging temperature (for example, the preset charging temperature is 0°C) and a preset state of charge (for example, the preset state of charge is 50%), a test charging current is used to charge the lithium battery to detect whether there is lithium deposition during the charging process of the lithium battery;

[0086] If the lithium battery at this moment has lithium deposition, it proves that the preset negative electrode potential before the second negative electrode potential is increased is the upper limit negative electrode potential; if the lithium battery at this moment does not have lithium deposition, it proves that the second negative electrode potential needs to be reduced according to the above adjustment method to obtain the upper limit negative electrode potential corresponding to the lithium battery simulation model, and the upper limit negative electrode potential is the threshold negative electrode potential corresponding to the simulation lithium battery model. When the upper limit negative electrode potential is determined, the preset charging temperature and the preset state of charge are input into the lithium battery simulation model to determine the upper limit charging current corresponding to the simulation lithium battery model, and then the upper limit charging rate corresponding to the simulation lithium battery model is obtained. Similarly, by increasing or decreasing the preset charging temperature and repeating the first adjustment process, the upper limit charging rate at multiple specific temperatures can be obtained.

[0087] In some embodiments, the threshold cathode potential is 0 V-0.06 V. For example, the threshold cathode potential may be 0 V, 0.01 V, 0.02 V, 0.03 V, 0.04 V, 0.05 V, and 0.06 V. In some possible implementations, the upper cathode potential is 0 V-0.06 V.

[0088] In some embodiments, the predetermined step size is 0.002 V-0.005 V. For example, the predetermined step size may be 0.002 V, 0.003 V, 0.004 V, 0.005 V.

[0089] The predetermined step length is controlled within the above range, the value of the predetermined step length is moderate, the corrected preset negative electrode potential and the upper limit negative electrode potential have a high correspondence, and the time consumed by the preset negative electrode potential to be corrected to the upper limit negative electrode potential is short. In addition, it can alleviate the situation that the value of the predetermined step length is too large, there may be a large difference between the corrected preset negative electrode potential and the upper limit negative electrode potential, and the correspondence between the corrected preset negative electrode potential and the upper limit negative electrode potential is poor. It can also alleviate the situation that the value of the predetermined step length is small, although the corrected preset negative electrode potential and the upper limit negative electrode potential have a high correspondence, the time consumed by the preset negative electrode potential to be corrected to the upper limit negative electrode potential is too long.

[0090] The embodiment of the present application provides a device for detecting the charging boundary of a lithium battery, referring to Figure 3 , the device 100 for detecting the charging boundary of a lithium battery includes: a modeling module 110, which is used to construct a lithium battery simulation model; the lithium battery simulation model is used to represent the relationship between input parameters and output parameters, and the input parameters include the charging temperature, charging current and state of charge of the lithium battery; the output parameters include the negative electrode potential; a processing module 120, which is used to obtain a test charging current based on a preset negative electrode potential, a preset charging temperature, a preset state of charge and the lithium battery simulation model; a detection module 130, which is used to detect the lithium precipitation phenomenon generated after the lithium battery is charged with the test charging current; the processing module 120 is also used to obtain a threshold negative electrode potential obtained after correcting the preset negative electrode potential according to the detection result. In this way, the charging boundary of the lithium battery can be accurately measured by a device with a simple structure, which can reduce the detection process and reduce the detection cost.

[0091] In addition, the device for detecting the charging boundary of a lithium battery can also be used to implement other operations of the above-mentioned method for detecting the charging boundary of a lithium battery.

[0092] The embodiment of the present application provides a charging detection method, referring to Figure 4 ,include:

[0093] S10: Determine the current negative electrode potential based on a preset charging temperature, a preset state of charge, a charging current and a lithium battery simulation model, wherein the lithium battery simulation model is used to represent the relationship between input parameters and output parameters, the input parameters include the charging temperature, charging current and state of charge of the lithium battery; the output parameters include the negative electrode potential.

[0094] In this step, the preset charging temperature, the preset state of charge, and the charging current are input into the lithium battery simulation model to obtain the current negative electrode potential.

[0095] In some embodiments, the preset charging temperature, preset state of charge, charging current corresponding to the threshold negative electrode potential, threshold negative electrode potential and lithium battery simulation model in the method for detecting the charging boundary of a lithium battery in the above embodiments are imported into a battery management system.

[0096] In other words, in the above-mentioned charging detection method, the preset charging temperature is the preset charging temperature in the above-mentioned method for detecting the charging boundary of a lithium battery, the preset state of charge is the preset state of charge in the above-mentioned method for detecting the charging boundary of a lithium battery, the charging current is the charging current corresponding to the threshold negative electrode potential in the above-mentioned method for detecting the charging boundary of a lithium battery, and the predetermined negative electrode potential is the threshold negative electrode potential in the above-mentioned method for detecting the charging boundary of a lithium battery. The charging current corresponding to the threshold negative electrode potential represents: when the threshold negative electrode potential is determined, the charging current obtained by inputting the preset charging temperature and the preset state of charge into the lithium battery simulation model.

[0097] S20: Based on the difference between the current negative electrode potential and the predetermined negative electrode potential, the charging current is corrected, and the lithium battery is charged with the corrected current charging current.

[0098] In this step, the preset charging temperature, the preset state of charge, the charging current corresponding to the predetermined negative electrode potential, and the lithium battery simulation model are imported into the charging system. In the process of charging the lithium battery using the battery management system, the charging current is corrected based on the difference between the current negative electrode potential and the predetermined negative electrode potential. The lithium battery is charged with the corrected current charging current, which can not only improve the charging efficiency of the battery management system, but also improve the safety during the charging process.

[0099] In some embodiments, the preset charging temperature, preset state of charge, charging current corresponding to the threshold negative electrode potential, threshold negative electrode potential, and lithium battery simulation model in the method for detecting the charging boundary of the lithium battery in the above embodiment are imported into the battery management system. Based on the difference between the current negative electrode potential and the threshold negative electrode potential, the charging current is corrected, and the lithium battery is charged with the corrected current charging current. The current negative electrode potential generated by the battery management system may be different from the threshold negative electrode potential because: the preset charging temperature, preset state of charge, charging current corresponding to the predetermined negative electrode potential, predetermined negative electrode potential, and lithium battery simulation model in the method for detecting the charging boundary of the lithium battery are imported into the battery management system. The battery management system is a new application scenario, which may cause the current negative electrode potential generated by the battery management system to be different from the threshold negative electrode potential.

[0100] In some embodiments, when it is determined that the current negative electrode potential is less than the predetermined negative electrode potential, the charging current is increased and the first upper limit charging current is determined. When it is determined that the current negative electrode potential is less than the predetermined negative electrode potential, it proves that the current negative electrode potential is small. If the charging current corresponding to the predetermined negative electrode potential is less than the maximum safe current that the battery management system can carry, therefore, by increasing the charging current to determine the first upper limit charging current, the first upper limit charging current is closer to the maximum safe current that the battery management system can carry, which is beneficial to improving the charging efficiency of the battery management system. The predetermined negative electrode potential here can be the upper limit negative electrode potential in the method for detecting the charging boundary of a lithium battery in the above-mentioned embodiment.

[0101] Furthermore, in the battery management system, at a preset charging temperature and a preset state of charge, the lithium battery is charged with a first upper limit charging current to determine the first negative electrode potential, and the first negative electrode potential is compared with the upper limit negative electrode potential. If the first negative electrode potential is still less than the upper limit negative electrode potential, the first upper limit charging current can be increased until the negative electrode potential corresponding to the increased first upper limit charging current is greater than and close to the upper limit negative electrode potential.

[0102] In some embodiments, when it is determined that the current negative electrode potential is greater than the predetermined negative electrode potential, the charging current is reduced and a second upper limit charging current is determined. When it is determined that the current negative electrode potential is greater than the predetermined negative electrode potential, it proves that the current negative electrode potential may be large, and the charging current corresponding to the predetermined negative electrode potential may be greater than the maximum safe current that the battery management system can carry. Therefore, by reducing the charging current to determine the second upper limit charging current, the second upper limit charging current is closer to the maximum safe current that the battery management system can carry, which is beneficial to improving the charging safety of the battery management system. The predetermined negative electrode potential here can be the upper limit negative electrode potential in the method for detecting the charging boundary of a lithium battery in the above-mentioned embodiment.

[0103] Furthermore, in the battery management system, at a preset charging temperature and a preset state of charge, the lithium battery is charged with a second upper limit charging current to determine the second negative electrode potential, and the second negative electrode potential is compared with the upper limit negative electrode potential. If the second negative electrode potential is still greater than the upper limit negative electrode potential, the second upper limit charging current can be further reduced until the negative electrode potential corresponding to the reduced second upper limit charging current is greater than and close to the upper limit negative electrode potential.

[0104] In some embodiments, it also includes: when the current negative electrode potential is about to or has been less than the predetermined negative electrode potential, the battery management system will issue a warning message. When the battery management system issues a warning message, it can remind the operator to reduce the charging current in time, realize early diagnosis and warning of overcharging, help optimize the use conditions of lithium batteries, and improve the safety of lithium batteries. The predetermined negative electrode potential here can be the upper limit negative electrode potential in the method for detecting the charging boundary of the lithium battery in the above embodiment.

[0105] For example, if the current negative electrode potential is 0.005V and the upper limit negative electrode potential is 0.002V, no warning information will be issued and normal charging can be performed. For another example, if the current negative electrode potential is 0.0025V and the upper limit negative electrode potential is 0.002V, since lithium battery charging is a dynamic process, in the case of inevitable acquisition errors, model errors, and prediction algorithm errors, the current negative electrode potential (0.0025V) may be close to the upper limit negative electrode potential (0.002V). There may be a risk of lithium plating during the charging process of the lithium battery. At this moment, the battery management system may issue a warning message to remind the operator to reduce the charging current in time so that the negative electrode potential is always higher than the lithium plating potential of the lithium battery during the charging process.

[0106] The embodiment of the present application provides a battery management system, referring to Figure 5 The battery management system 14 includes a management module 140, which is used to determine the current negative electrode potential according to the preset charging temperature, the preset state of charge, the charging current and the lithium battery simulation model; the lithium battery simulation model is used to represent the relationship between the input parameters and the output parameters, and the input parameters include the charging temperature, the charging current and the state of charge of the lithium battery; the output parameters include the negative electrode potential; the control module 141 is used to correct the charging current based on the difference between the current negative electrode potential and the preset negative electrode potential, and charge the lithium battery with the corrected charging current. In this way, the above battery management system has a simple structure and a better charging effect on the lithium battery.

[0107] In some embodiments, the battery management system 14 may further include an acquisition module (for example, the acquisition module may be a sensor), which may import the preset charging temperature, preset state of charge, charging current corresponding to the threshold negative electrode potential, threshold negative electrode potential, and lithium battery simulation model in the method for detecting the charging boundary of the lithium battery in the above-mentioned embodiment into the battery management system. The threshold negative electrode potential may be used as the predetermined negative electrode potential.

[0108] In some embodiments, the battery management system 14 may further include a diagnostic warning module for diagnosing that when the current negative electrode potential is about to or has been less than a threshold negative electrode potential, the battery management system will issue a warning message to implement a warning.

[0109] In addition, the battery management system mentioned above may be used to process other operations in the charging detection method mentioned above.

[0110] The embodiments of the present application provide a readable storage medium, on which a program or instruction is stored, and when the program or instruction is executed by a processor, a method for detecting the charging boundary of a lithium battery as in the above embodiment is implemented, and / or the steps of the charging detection method as in the above embodiment are implemented, and the same technical effect can be achieved. To avoid repetition, it is not repeated here. In some possible implementations, the readable storage medium includes at least one of a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0111] Figure 6 is a block diagram of a vehicle according to an exemplary embodiment. Figure 6 As shown, the vehicle 200 includes but is not limited to: a processor 201 and a memory 202. The memory 202 is used to store executable instructions of the processor 201, and the processor 201 is configured to execute instructions to implement the charging detection method in the above embodiment. In this way, the service life of the vehicle can be improved. It should be noted that those skilled in the art can understand that Figure 6 The vehicle structure shown in the figure does not constitute a limitation on the vehicle, and the vehicle may include Figure 6 More or fewer components may be shown, or certain components may be combined, or the components may be arranged differently.

[0112] The processor 201 is the control center of the vehicle, which uses various interfaces and lines to connect various parts of the entire vehicle, and executes various functions of the vehicle and processes data by running or executing software programs and / or modules stored in the memory 202, and calling data stored in the memory 202, so as to monitor the vehicle as a whole. The processor 201 may include one or more processing units. Optionally, the processor 201 may integrate an application processor and a modem processor, wherein the application processor mainly processes the operating system, user interface, and application programs, etc., and the modem processor mainly processes wireless communications. It is understandable that the above-mentioned modem processor may not be integrated into the processor 201.

[0113] The memory 202 can be used to store software programs and various data. The memory 202 can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, an application program required by at least one functional module (such as a determination unit, a judgment unit, a control unit), etc. In addition, the memory 202 can include a high-speed random access memory, and can also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0114] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for detecting the charging boundary of a lithium battery, characterized in that: include: Build a lithium battery simulation model; The lithium battery simulation model is used to represent the relationship between input parameters and output parameters, wherein the input parameters include the charging temperature, charging current and state of charge of the lithium battery; and the output parameters include the negative electrode potential; Determining a test charging current based on a preset negative electrode potential, a preset charging temperature, a preset state of charge, and the lithium battery simulation model; At the preset charging temperature and the preset state of charge, the lithium battery is charged with the test charging current to detect whether lithium deposition occurs in the lithium battery during the charging process, and the preset negative electrode potential is corrected according to the detection result to obtain a threshold negative electrode potential.

2. The method according to claim 1, characterized in that Correcting the preset negative electrode potential according to the detection result includes: When the lithium deposition phenomenon is detected during the charging process of the lithium battery, the preset negative electrode potential is increased by a predetermined step length to obtain a first negative electrode potential.

3. The method according to claim 2, characterized in that The method further comprises: Determining a first charging current based on the first negative electrode potential, the preset charging temperature, the preset state of charge, and the lithium battery simulation model; At the preset charging temperature and the preset state of charge, the lithium battery is charged with the first charging current, and when it is detected that the lithium battery does not have the lithium plating phenomenon during the charging process, the first negative electrode potential is determined to be the upper limit negative electrode potential, and the upper limit negative electrode potential is used as the threshold negative electrode potential.

4. The method according to claim 1, characterized in that: Correcting the preset negative electrode potential according to the detection result includes: When it is detected that the lithium battery does not have the lithium deposition phenomenon during the charging process, the preset negative electrode potential is reduced by a predetermined step length to obtain a second negative electrode potential.

5. The method according to claim 4, characterized in that The method further comprises: Determining a second charging current based on the second negative electrode potential, the preset charging temperature, the preset state of charge, and the lithium battery simulation model; At the preset charging temperature and the preset state of charge, the lithium battery is charged with the second charging current, and when the lithium plating phenomenon is detected in the lithium battery during the charging process, the preset negative electrode potential before correction adjacent to the second preset electrode is determined as the upper limit negative electrode potential, and the upper limit negative electrode potential is used as the threshold negative electrode potential.

6. The method according to claim 3 or 5, characterized in that: An upper limit charging current is determined based on the upper limit negative electrode potential, the preset charging temperature, the preset state of charge, and the lithium battery simulation model.

7. The method according to any one of claims 2 to 5, characterized in that: The threshold negative electrode potential is 0V-0.06V, and the predetermined step size is 0.002V-0.005V.

8. A charging detection method, characterized in that: Determine the current negative electrode potential based on a preset charging temperature, a preset state of charge, a charging current, and a lithium battery simulation model; the lithium battery simulation model is used to represent the relationship between input parameters and output parameters, the input parameters include the charging temperature, charging current, and state of charge of the lithium battery; the output parameters include the negative electrode potential; Based on the difference between the current negative electrode potential and the predetermined negative electrode potential, the charging current is corrected, and the lithium battery is charged by the corrected charging current.

9. The charging detection method according to claim 8, characterized in that: Correcting the charging current includes: When it is determined that the current negative electrode potential is less than the predetermined negative electrode potential, increasing the charging current and determining a first upper limit charging current; Or, when it is determined that the current negative electrode potential is greater than the predetermined negative electrode potential, the charging current is reduced and a second upper limit charging current is determined.

10. The charging detection method according to claim 8 or 9, characterized in that: Also includes: When the current negative electrode potential is about to be or has been less than the predetermined negative electrode potential, the battery management system will issue a warning message.

11. A device for detecting the charging boundary of a lithium battery, characterized in that: include: Modeling module, used to build lithium battery simulation model; The lithium battery simulation model is used to represent the relationship between input parameters and output parameters, wherein the input parameters include the charging temperature, charging current and state of charge of the lithium battery; and the output parameters include the negative electrode potential; A processing module, used for obtaining a test charging current based on a preset negative electrode potential, a preset charging temperature, a preset state of charge and the lithium battery simulation model; A detection module, used to detect lithium deposition caused by charging the lithium battery with the test charging current; The processing module is further used to obtain a threshold negative electrode potential obtained by correcting the preset negative electrode potential according to the detection result.

12. A battery management system, characterized in that: include: A management module, used to determine the current negative electrode potential according to a preset charging temperature, a preset state of charge, a charging current and a lithium battery simulation model; The lithium battery simulation model is used to represent the relationship between input parameters and output parameters, wherein the input parameters include the charging temperature, charging current and state of charge of the lithium battery; and the output parameters include the negative electrode potential; The control module is used to correct the charging current based on the difference between the current negative electrode potential and the predetermined negative electrode potential, and charge the lithium battery with the corrected charging current.

13. A readable storage medium, characterized in that: When the computer-executable instructions stored in the readable storage medium are executed by the processor of a device for detecting the charging boundary of a lithium battery, they are used to implement the method for detecting the charging boundary of a lithium battery as described in any one of claims 1 to 7; when the computer-executable instructions stored in the readable storage medium are executed by the processor of a vehicle, they are used to implement the charging detection method as described in any one of claims 8 to 10.

14. A vehicle, characterized in that: include: processor; A memory for storing instructions executable by the processor; wherein the processor is configured to execute the instructions to implement the charging detection method according to any one of claims 8 to 10.

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