Battery lithium deposition detection method, device, readable storage medium and battery management system

Abstract

The present application belongs to the field of battery technology, and in particular, relates to a battery lithium plating detection method, device, readable storage medium and battery management system. The method includes: determining the cycle energy efficiency and health status of the battery in the charge and discharge test; determining the efficiency health change rate of the battery according to the cycle energy efficiency and the health status of the battery in the charge and discharge test; the efficiency health change rate characterizes the change of the cycle energy efficiency change with the change of the health status; determining the lithium plating detection result of the battery according to the efficiency health change rate and the change rate threshold; the change rate threshold characterizes the critical value of the efficiency health change rate when lithium plating occurs in the battery. Through the present application, the efficiency health change rate of the battery can be determined, and the lithium plating detection result of the battery can be determined accordingly. No high-precision equipment is required to perform any special tests. The whole process is simple and easy, with low complexity, and can be more widely used.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and in particular relates to a battery lithium deposition detection method, device, computer-readable storage medium and battery management system. Background Art

[0002] In the prior art, there are two methods for detecting lithium deposition in lithium-ion batteries. One is to visually inspect the lithium deposition status of the anode interface after destructive disassembly; the other method is to detect the battery without disassembling it, using means such as sound, light, and electromagnetics, and obtain an estimate of the amount of lithium deposition by analyzing the measured signal. Among them, the second method is the most commonly used measurement of electrical signals. By performing differential processing on the charge and discharge signals, the offset of the differential signal is obtained to analyze the state changes of the anode and cathode inside the battery. However, this method often requires high-precision equipment to perform special tests such as electrochemical impedance spectroscopy testing, which is highly complex and difficult to be widely used. Summary of the invention

[0003] In view of this, the embodiments of the present application provide a battery lithium deposition detection method, device, computer-readable storage medium and battery management system to solve the problem that the existing battery lithium deposition detection method is highly complex and difficult to be widely used.

[0004] A first aspect of an embodiment of the present application provides a battery lithium deposition detection method, which may include:

[0005] Determine the cycle energy efficiency and health status of the battery during charge and discharge tests;

[0006] The efficiency health change rate of the battery is determined according to the cycle energy efficiency and health status of the battery in the charge and discharge test; the efficiency health change rate represents the change of the cycle energy efficiency change with the health status change; the cycle energy efficiency change is the difference between the cycle energy efficiencies in different charge and discharge tests; the health status change is the difference between the health status in different charge and discharge tests;

[0007] The lithium plating detection result of the battery is determined based on the efficiency health change rate and the change rate threshold; the change rate threshold represents the critical value of the efficiency health change rate when lithium plating occurs in the battery.

[0008] Through the above method, the efficiency health change rate of the battery can be determined according to the cycle energy efficiency and health status of the battery in the charge and discharge test, and the lithium plating detection result of the battery can be determined according to the efficiency health change rate. No high-precision equipment is required for any special test. The whole process is simple and easy, with low complexity, and can be more widely used.

[0009] In a specific implementation of the first aspect, determining the efficiency health change rate of the battery according to the cycle energy efficiency and health status of the battery in a charge and discharge test may include:

[0010] Determining a first cycle energy efficiency and a first state of health of the battery in a first charge and discharge test; the first charge and discharge test characterizing a previous charge and discharge test;

[0011] Determine the second cycle energy efficiency and the second health state of the battery in the second charge and discharge test; the second charge and discharge test characterizes the subsequent charge and discharge test;

[0012] An efficiency health change rate of the battery is determined based on the first cycle energy efficiency, the first health state, the second cycle energy efficiency, and the second health state.

[0013] In a specific implementation of the first aspect, determining the efficiency health change rate of the battery according to the first cycle energy efficiency, the first health state, the second cycle energy efficiency, and the second health state may include:

[0014] determining a change in cycle energy efficiency between the second cycle energy efficiency and the first cycle energy efficiency;

[0015] determining a change in health state between the second health state and the first health state;

[0016] The ratio between the change in cycle energy efficiency and the change in health status is determined as the efficiency health change rate of the battery.

[0017] Through the above method, the change in the battery's cycle energy efficiency and health status before and after two times can be determined respectively. The efficiency health change rate obtained thereby can accurately reflect the changing trend of the battery's cycle energy efficiency with its health status.

[0018] In a specific implementation of the first aspect, determining a lithium plating detection result of a battery according to an efficiency health change rate and a change rate threshold may include:

[0019] When the efficiency health change rate is greater than or equal to the change rate threshold, it is determined that the lithium deposition test result of the battery is that no lithium deposition has occurred;

[0020] When the efficiency health change rate is less than the change rate threshold, it is determined that the lithium plating detection result of the battery is that lithium plating has occurred.

[0021] Through the above method, the objective standard of change rate threshold is adopted to determine whether lithium plating occurs in the battery, which can reduce the interference of subjective opinions of testers and effectively improve the accuracy of lithium plating test results.

[0022] In a specific implementation manner of the first aspect, the value range of the change rate threshold may include [0, 0.1].

[0023] In a specific implementation of the first aspect, before determining the lithium plating detection result of the battery according to the efficiency health change rate and the change rate threshold, the method may also include:

[0024] Determine the efficiency health change rate of the sample battery in the charge and discharge test; wherein the model of the sample battery is consistent with the model of the battery;

[0025] In the case where lithium deposition occurs in the sample battery, the efficiency health change rate corresponding to the lithium deposition occurs in the sample battery is determined as the change rate threshold.

[0026] Through the above method, the change rate threshold can be determined by actual sample measurement, so that the setting of the change rate threshold is more accurate and reasonable, thereby further improving the accuracy of the lithium plating detection result.

[0027] In a specific implementation of the first aspect, before determining the lithium plating detection result of the battery according to the efficiency health change rate and the change rate threshold, the method may also include:

[0028] According to the change rate threshold corresponding relationship, the change rate threshold corresponding to the battery is determined; the change rate threshold corresponding relationship represents the corresponding relationship between the battery and the change rate threshold.

[0029] Through the above method, different change rate thresholds can be set in advance for different batteries, so that the setting of the change rate threshold is more refined, thereby further improving the accuracy of the lithium plating detection result.

[0030] In a specific implementation of the first aspect, determining the cycle energy efficiency of the battery in a charge and discharge test may include:

[0031] Determine the charge energy of the battery during charge and discharge tests;

[0032] Determine the discharge energy of the battery during charge and discharge tests;

[0033] Based on the charging energy and discharging energy, the cycle energy efficiency of the battery in the charge and discharge test is determined.

[0034] In a specific implementation of the first aspect, determining a health status of a battery in a charge and discharge test may include:

[0035] Determine the current capacity of the battery during charge and discharge tests;

[0036] Determine the health status of the battery during charge and discharge tests based on the current capacity and rated capacity.

[0037] A second aspect of the embodiments of the present application provides a battery lithium deposition detection device, which may include:

[0038] A parameter determination module is used to determine the cycle energy efficiency and health status of the battery during charge and discharge tests;

[0039] The change rate determination module is used to determine the efficiency health change rate of the battery according to the cycle energy efficiency and health status of the battery in the charge and discharge test; the efficiency health change rate represents the change of the cycle energy efficiency change with the health status change; the cycle energy efficiency change is the difference between the cycle energy efficiencies in different charge and discharge tests; the health status change is the difference between the health status in different charge and discharge tests;

[0040] The lithium plating detection module is used to determine the lithium plating detection result of the battery according to the efficiency health change rate and the change rate threshold; the change rate threshold represents the critical value of the efficiency health change rate when lithium plating occurs in the battery.

[0041] Through the above device, the efficiency health change rate of the battery can be determined according to the cycle energy efficiency and health status of the battery in the charge and discharge test, and the lithium plating detection result of the battery can be determined according to the efficiency health change rate. No high-precision equipment is required for any special test. The whole process is simple and easy, with low complexity, and can be used in a wider range of applications.

[0042] In a specific implementation of the second aspect, the change rate determination module may include:

[0043] A first parameter determination unit, used to determine a first cycle energy efficiency and a first health state of the battery in a first charge and discharge test; the first charge and discharge test characterizes a previous charge and discharge test;

[0044] A second parameter determination unit is used to determine a second cycle energy efficiency and a second health state of the battery in a second charge and discharge test; the second charge and discharge test represents a subsequent charge and discharge test;

[0045] The change rate determination unit is used to determine the efficiency health change rate of the battery according to the first cycle energy efficiency, the first health state, the second cycle energy efficiency and the second health state.

[0046] In a specific implementation of the second aspect, the change rate determination unit can be specifically used to: determine the change in cycle energy efficiency between the second cycle energy efficiency and the first cycle energy efficiency; determine the change in health state between the second health state and the first health state; and determine the ratio between the change in cycle energy efficiency and the change in health state as the efficiency health change rate of the battery.

[0047] Through the above device, the change in cycle energy efficiency and health status of the battery before and after two times can be determined respectively. The efficiency health change rate obtained thereby can accurately reflect the changing trend of the battery's cycle energy efficiency with health status.

[0048] In a specific implementation of the second aspect, the lithium deposition detection module can be specifically used to: when the efficiency health change rate is greater than or equal to the change rate threshold, determine that the lithium deposition detection result of the battery is that lithium deposition has not occurred; when the efficiency health change rate is less than the change rate threshold, determine that the lithium deposition detection result of the battery is that lithium deposition has occurred.

[0049] Through the above device, the objective standard of change rate threshold is adopted to determine whether lithium plating occurs in the battery, which can reduce the interference of subjective opinions of testers and effectively improve the accuracy of lithium plating test results.

[0050] In a specific implementation manner of the second aspect, the value range of the change rate threshold may include [0, 0.1].

[0051] In a specific implementation of the second aspect, the battery lithium deposition detection device may further include:

[0052] The first threshold determination module is used to determine the efficiency health change rate of the sample battery in the charge and discharge test; wherein the model of the sample battery is consistent with the model of the battery; in the case that lithium deposition occurs in the sample battery, the efficiency health change rate corresponding to the lithium deposition of the sample battery is determined as the change rate threshold.

[0053] Through the above device, the change rate threshold can be determined by actual sample measurement, so that the setting of the change rate threshold is more accurate and reasonable, thereby further improving the accuracy of the lithium plating detection result.

[0054] In a specific implementation of the second aspect, the battery lithium deposition detection device may further include:

[0055] The second threshold determination module is used to determine the change rate threshold corresponding to the battery according to the change rate threshold corresponding relationship; the change rate threshold corresponding relationship represents the corresponding relationship between the battery and the change rate threshold.

[0056] Through the above device, different change rate thresholds can be set in advance for different batteries, making the setting of the change rate threshold more refined, thereby further improving the accuracy of the lithium plating detection result.

[0057] In a specific implementation of the second aspect, the parameter determination module may include:

[0058] The cycle energy efficiency determination unit is used to determine the charging energy of the battery in the charge and discharge test; determine the discharge energy of the battery in the charge and discharge test; and determine the cycle energy efficiency of the battery in the charge and discharge test based on the charging energy and the discharge energy.

[0059] In a specific implementation of the second aspect, the parameter determination module may include:

[0060] The health status determination unit is used to determine the current capacity of the battery during the charge and discharge test; and determine the health status of the battery during the charge and discharge test based on the current capacity and the rated capacity.

[0061] A third aspect of an embodiment of the present application provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps of any of the above-mentioned battery lithium deposition detection methods are implemented.

[0062] A fourth aspect of an embodiment of the present application provides a battery management system, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of any of the above-mentioned battery lithium deposition detection methods when executing the computer program.

[0063] A fifth aspect of an embodiment of the present application provides a computer program product. When the computer program product is run on a battery management system, the battery management system executes the steps of any one of the above-mentioned battery lithium deposition detection methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0065] Figure 1 It is a schematic diagram of the anode impedance when no lithium deposition occurs in the battery;

[0066] Figure 2 It is a schematic diagram of the anode impedance when lithium deposition occurs in the battery;

[0067] Figure 3 A trend chart showing the cycle energy efficiency of the battery as it changes with its health status after charge and discharge tests;

[0068] Figure 4 This is a schematic diagram of a large area of ​​lithium deposition on the internal anode plate of a battery;

[0069] Figure 5This is a flow chart of an embodiment of a battery lithium deposition detection method in an embodiment of the present application;

[0070] Figure 6 This is a structural diagram of an embodiment of a battery lithium deposition detection device in an embodiment of the present application;

[0071] Figure 7 This is a schematic block diagram of a battery management system in an embodiment of the present application. DETAILED DESCRIPTION

[0072] In order to make the purpose, features, and advantages of the invention of this application more obvious and easy to understand, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the embodiments described below are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0073] It should be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0074] It should also be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0075] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0076] As used in this specification and the appended claims, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined" or "if [described condition or event] is detected" may be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0077] In addition, in the description of the present application, the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0078] In the prior art, there are two methods for detecting lithium deposition in lithium-ion batteries. One is to visually inspect the lithium deposition status of the anode interface after destructive disassembly; the other method is to detect the battery without disassembling it, using means such as sound, light, and electromagnetics, and obtain an estimate of the amount of lithium deposition by analyzing the measured signal. Among them, the second method is the most commonly used measurement of electrical signals. By performing differential processing on the charge and discharge signals, the offset of the differential signal is obtained to analyze the state changes of the anode and cathode inside the battery. However, this method often requires high-precision equipment to perform special tests such as electrochemical impedance spectroscopy testing, which is highly complex and difficult to be widely used.

[0079] In view of this, the embodiments of the present application provide a battery lithium deposition detection method, device, computer-readable storage medium and battery management system (Battery Management System, BMS) to solve the problem that the existing battery lithium deposition detection method is highly complex and difficult to be widely used. The principle of battery lithium deposition detection in the embodiments of the present application will be described in detail below.

[0080] Figure 1 The figure shows the schematic diagram of the anode impedance of the battery when no lithium deposition occurs. When no lithium deposition occurs in the battery, the anode impedance of the battery is mainly composed of ohmic impedance, charge transfer impedance and diffusion impedance in series. As the battery ages, its ohmic impedance and diffusion impedance will continue to increase. The increase in impedance causes the battery's round trip efficiency (RTE) to decrease. Figure 2 The figure shows the schematic diagram of the anode impedance when the battery undergoes lithium deposition. When lithium deposition occurs in the battery, lithium metal is generated inside the anode and the solid electrolyte interface (SEI), which is equivalent to connecting a resistor in parallel to the original impedance, causing the overall impedance to decrease. The impedance reduction causes the battery's cycle energy efficiency to increase. When combined with the original downward trend in cycle energy efficiency, the battery's cycle energy efficiency will show a phenomenon in which the downward trend slows down significantly or tends to level off.

[0081] To verify this, in the embodiment of the present application, a predetermined number of batteries can be subjected to continuous cycle aging, and a charge and discharge test can be performed on the batteries every several days to determine the cycle energy efficiency and health state (State of Health, SOH) in each charge and discharge test. The health state in each charge and discharge test is used as the horizontal axis, and the cycle energy efficiency is used as the vertical axis, and the following can be obtained: Figure 3The cycle energy efficiency changes with the health state as shown in the figure. It can be seen from the figure that when the health state is around 90%, the cycle energy efficiency trend changes and tends to be flat. At this time, a parallel sample with a health state close to 90% is disassembled and observed. The state of its internal anode electrode is shown in 4, and a large area of ​​lithium deposition occurs, which proves that the battery has a large area of ​​lithium deposition when the health state is around 90%.

[0082] Based on the above principles, the embodiments of the present application can determine the efficiency health change rate of the battery according to the cycle energy efficiency and health status of the battery in the charge and discharge test, and determine the lithium plating detection result of the battery according to the efficiency health change rate. No high-precision equipment is required for any special testing. The whole process is simple and easy, with low complexity, and can be more widely used.

[0083] The execution entity of the battery lithium deposition detection method provided in the embodiment of the present application may include but is not limited to a battery management system.

[0084] See also Figure 5 In the embodiment of the present application, an embodiment of a battery lithium deposition detection method may include:

[0085] Step S501: Determine the cycle energy efficiency and health status of the battery in the charge and discharge test.

[0086] The battery may be any battery to be subjected to battery lithium deposition detection, and the embodiment of the present application does not specifically limit its specific model.

[0087] In the embodiment of the present application, the battery can be charged and discharged once every period of time (i.e., test cycle) to determine its cycle energy efficiency and health status. The specific value of the test cycle can be set according to actual conditions, for example, it can include but is not limited to 2 months, 3 months, half a year or other values.

[0088] In order to improve the reliability of the charge and discharge test results, the test conditions of each charge and discharge test should be as close and consistent as possible. For example, the same charge and discharge ambient temperature and constant charge and discharge rate can be maintained as much as possible. The specific value of the ambient temperature can be set according to the actual situation, for example, it can include but is not limited to 60°C, 50°C, 40°C or other values. The specific value of the charge and discharge rate can be set according to the actual situation, for example, it can include but is not limited to 0.33C, 0.2C, 0.5C or other values.

[0089] Each charge and discharge test process can include the following steps:

[0090] (1) Leave the battery to rest for the preset rest time.

[0091] The specific value of the static time can be set according to actual conditions, for example, it can include but is not limited to 30 minutes, 25 minutes, 20 minutes or other values.

[0092] (2) Discharge the battery at a preset charge and discharge rate until it reaches a preset lower cut-off voltage.

[0093] The specific value of the lower cut-off voltage may be set according to actual conditions, for example, it may include but is not limited to 2.5V, 2.45V, 2.4V or other values.

[0094] (3) Leave the battery to rest for a preset time.

[0095] (4) Charge the battery at a preset charge and discharge rate until it reaches a preset upper cut-off voltage.

[0096] The specific value of the upper cut-off voltage can be set according to actual conditions, for example, it can include but is not limited to 3.65V, 3.6V, 3.55V or other values.

[0097] (5) Leave the battery to rest for a preset time.

[0098] (6) Discharge the battery at a preset charge and discharge rate until it reaches a preset lower cut-off voltage.

[0099] It is easy to understand that step (2) can create the starting conditions for fully charging and discharging the battery, step (4) is the full charging process of the battery, and step (6) is the full discharging process of the battery.

[0100] In each charge and discharge test, the cycle energy efficiency and health status of the battery can be determined respectively. The specific determination method can be set according to the actual situation, and can include but is not limited to any cycle energy efficiency determination method and health status determination method in the prior art.

[0101] As an example, in a specific implementation of the embodiment of the present application, the charging energy and the discharging energy of the battery in the charging and discharging test can be determined respectively according to the following formulas:

[0102] Charging energy = Σ ((charging OCV + charging current × charging impedance) × charging current × Δ time))

[0103] Discharge energy = Σ ((discharge OCV - discharge current × discharge impedance) × discharge current × Δ time))

[0104] Among them, charging OCV (Open Circuit Voltage) is the open circuit voltage of the battery during charging, discharging OCV is the open circuit voltage of the battery during discharging, Δ time is the time differential unit, charging energy is the total energy charged into the battery in step (4), and discharging energy is the total energy discharged from the battery in step (6).

[0105] Then, the cycle energy efficiency of the battery in the charge and discharge test can be determined based on the charge energy and the discharge energy. That is, the cycle energy efficiency is the ratio between the discharge energy and the charge energy, as shown in the following formula:

[0106] Cycle energy efficiency = discharge energy / charge energy.

[0107] As an example, in a specific implementation of the embodiment of the present application, the capacity of the battery in the charge and discharge test can be determined according to the following formula:

[0108] Capacity in the charge and discharge test = Σ (charge and discharge current × Δ time).

[0109] That is, the capacity in the charge and discharge test is the cumulative value of the product of the charge and discharge current and the time differential unit. Among them, the capacity here can be the charging capacity, that is, the total capacity charged into the battery in step (4), then the charge and discharge current in the formula refers to the charging current; the capacity here can also be the discharge capacity, that is, the total capacity discharged from the battery in step (6), then the charge and discharge current in the formula refers to the discharge current. Since charging can often obtain better rate data, the polarization error after each full capacity is small, so it is more accurate to use the charging capacity at the same rate and temperature as the calculation data of the health status.

[0110] Then, the health state of the battery in the charge and discharge test can be determined according to the current capacity and the rated capacity of the battery in the charge and discharge test, that is, the health state is the ratio between the current capacity and the rated capacity in the charge and discharge test, as shown in the following formula:

[0111] Health status = current capacity during charge and discharge test / rated capacity.

[0112] Among them, the rated capacity is the maximum amount of electricity that the battery can output under ideal conditions (such as specific temperature, discharge rate and termination voltage).

[0113] After each charge and discharge test, the determined cycle energy efficiency and health status can be recorded and stored for subsequent analysis.

[0114] Step S502: Determine the efficiency health change rate of the battery according to the cycle energy efficiency and health status of the battery in the charge and discharge test.

[0115] Among them, the efficiency health change rate represents the change of the cycle energy efficiency change with the health status change; the cycle energy efficiency change is the difference between the cycle energy efficiencies in different charge and discharge tests; the health status change is the difference between the health status in different charge and discharge tests.

[0116] Since the battery is subjected to a charge and discharge test at regular intervals, in order to distinguish between the two charge and discharge tests, the previous charge and discharge test can be recorded as the first charge and discharge test, and the subsequent charge and discharge test can be recorded as the second charge and discharge test.

[0117] In a specific implementation of an embodiment of the present application, the cycle energy efficiency and health state of the battery in the first charge and discharge test can be determined, and for ease of distinction, they are recorded as the first cycle energy efficiency and the first health state, respectively. Similarly, the cycle energy efficiency and health state of the battery in the second charge and discharge test can be determined, and for ease of distinction, they are recorded as the second cycle energy efficiency and the second health state, respectively. Then, the efficiency health change rate of the battery can be determined based on the first cycle energy efficiency, the first health state, the second cycle energy efficiency, and the second health state.

[0118] In a specific implementation of the embodiment of the present application, the cycle energy efficiency change between the second cycle energy efficiency and the first cycle energy efficiency can be determined according to the following formula:

[0119] ΔRTE=RTE n+1 -RTE n

[0120] Among them, RTE n is the first cycle energy efficiency, RTE n+1 is the second cycle energy efficiency, ΔRTE is the second cycle energy efficiency RTE n+1 and the first cycle energy efficiency RTE n The change in cycle energy efficiency between .

[0121] The health state change amount between the second health state and the first health state may also be determined according to the following formula:

[0122] ΔSOH=SOH n+1 -SOH n

[0123] Among them, SOH n The first state of health, SOH n+1 is the second health state, ΔSOH is the second health state SOH n+1 and the first state of health SOH n The change in health status between.

[0124] Then, the efficiency health change rate of the battery can be determined according to the cycle energy efficiency change and the health state change, that is, the efficiency health change rate of the battery is the ratio between the cycle energy efficiency change and the health state change, as shown in the following formula:

[0125] k=ΔRTE / ΔSOH

[0126] Where k is the efficiency health change rate.

[0127] Step S503: determining the lithium plating detection result of the battery according to the efficiency health change rate and the change rate threshold.

[0128] Among them, the change rate threshold represents the critical value of the efficiency health change rate when lithium deposition occurs in the battery. After the efficiency health change rate is determined, it can be compared with the change rate threshold, and the lithium deposition detection result of the battery can be determined based on the comparison result. For example, when the efficiency health change rate is greater than or equal to the change rate threshold, it can be determined that the lithium deposition detection result of the battery is that no lithium deposition has occurred; when the efficiency health change rate is less than the change rate threshold, it can be determined that the lithium deposition detection result of the battery is that lithium deposition has occurred.

[0129] Among them, the specific value of the change rate threshold can be set according to actual conditions. For example, it can include but is not limited to [0, 0.1] or other value ranges. The value range of [0, 0.1] has a wide range of applicability and can be applied to a variety of different types of batteries, especially for the current mainstream lithium iron phosphate batteries, it can have a better detection effect.

[0130] In a specific implementation of the embodiment of the present application, different change rate thresholds can be set in advance for different battery models according to actual conditions, so as to establish a correspondence between each model and each change rate threshold, which is recorded as a change rate threshold correspondence relationship, for example, model A corresponds to change rate threshold 1, model B corresponds to change rate threshold 2, model C corresponds to change rate threshold 3, and so on. In the case where the change rate threshold needs to be determined, the battery model can be determined first, and then the change rate threshold corresponding to the battery can be determined according to the change rate threshold correspondence relationship.

[0131] In a specific implementation of the embodiment of the present application, the change rate threshold corresponding to the battery can be determined by testing. That is, the efficiency health change rate of the sample battery in the charge and discharge test is determined. In the case of lithium deposition in the sample battery, the efficiency health change rate corresponding to the lithium deposition of the sample battery is determined as the change rate threshold, wherein the model of the sample battery is consistent with the model of the battery to be measured. For example, the battery of this model can be placed at a typical operating temperature, and a cycle test can be performed in the range of 0% to 100% of the remaining power (State Of Charge, SOC), and the charge and discharge rate is the rated charge and discharge rate. After a certain number of cycles (for example, after 95% SOH), the charge and discharge rate of the cycle is gradually increased to create lithium deposition conditions, and the k value of each cycle is recorded. For example, when the SOH is between 95% and 92.5%, the charge and discharge rate can be 1.5 times the rated charge and discharge rate, and when the SOH is between 92.5% and 90%, the charge and discharge rate can be 2 times the rated charge and discharge rate. Disassemble each group of batteries after the test to observe whether lithium deposition occurs, and determine the relationship between the k value and lithium deposition through disassembly. For example, after disassembly, it is found that lithium deposition occurs in the group with a charge and discharge rate of 2 times the rated rate, and its corresponding k value is k1, while lithium deposition does not occur in the group with a charge and discharge rate of 1.5 times the rated rate, and its corresponding k value is k2. Then k1 can be used as the change rate threshold corresponding to this model.

[0132] In a specific implementation of the embodiment of the present application, when the lithium deposition detection result of the battery indicates that lithium deposition has occurred, an alarm message may be sent to a preset target device to remind relevant personnel to perform subsequent processing. The target device may include but is not limited to a vehicle control unit (VCU).

[0133] In summary, the embodiments of the present application determine the cycle energy efficiency and health status of the battery in the charge and discharge test; determine the efficiency health change rate of the battery according to the cycle energy efficiency and health status of the battery in the charge and discharge test; the efficiency health change rate characterizes the change of the cycle energy efficiency change with the health status change; the cycle energy efficiency change is the difference between the cycle energy efficiencies in different charge and discharge tests; the health status change is the difference between the health status in different charge and discharge tests; the battery lithium plating detection result is determined according to the efficiency health change rate and the change rate threshold; the change rate threshold characterizes the critical value of the efficiency health change rate when lithium plating occurs in the battery. Through the present application, the efficiency health change rate of the battery can be determined according to the cycle energy efficiency and health status of the battery in the charge and discharge test, and the battery lithium plating detection result can be determined according to the efficiency health change rate. No high-precision equipment is required for any special testing. The whole process is simple and easy, with low complexity, and can be more widely used.

[0134] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0135] Corresponding to a battery lithium deposition detection method in the above embodiment, Figure 6 A structural diagram of an embodiment of a battery lithium deposition detection device provided in an embodiment of the present application is shown.

[0136] In this embodiment, a battery lithium deposition detection device may include:

[0137] Parameter determination module 601, used to determine the cycle energy efficiency and health status of the battery in the charge and discharge test;

[0138] The change rate determination module 602 is used to determine the efficiency health change rate of the battery according to the cycle energy efficiency and health status of the battery in the charge and discharge test; the efficiency health change rate represents the change of the cycle energy efficiency change with the health status change; the cycle energy efficiency change is the difference between the cycle energy efficiencies in different charge and discharge tests; the health status change is the difference between the health status in different charge and discharge tests;

[0139] The lithium plating detection module 603 is used to determine the lithium plating detection result of the battery according to the efficiency health change rate and the change rate threshold; the change rate threshold represents the critical value of the efficiency health change rate when lithium plating occurs in the battery.

[0140] In a specific implementation of the embodiment of the present application, the change rate determination module may include:

[0141] A first parameter determination unit, used to determine a first cycle energy efficiency and a first health state of the battery in a first charge and discharge test; the first charge and discharge test characterizes a previous charge and discharge test;

[0142] A second parameter determination unit is used to determine a second cycle energy efficiency and a second health state of the battery in a second charge and discharge test; the second charge and discharge test represents a subsequent charge and discharge test;

[0143] The change rate determination unit is used to determine the efficiency health change rate of the battery according to the first cycle energy efficiency, the first health state, the second cycle energy efficiency and the second health state.

[0144] In a specific implementation of an embodiment of the present application, the change rate determination unit can be specifically used to: determine the change in cycle energy efficiency between the second cycle energy efficiency and the first cycle energy efficiency; determine the change in health state between the second health state and the first health state; and determine the ratio between the change in cycle energy efficiency and the change in health state as the efficiency health change rate of the battery.

[0145] In a specific implementation method of an embodiment of the present application, the lithium deposition detection module can be specifically used to: when the efficiency health change rate is greater than or equal to the change rate threshold, determine that the lithium deposition detection result of the battery is that lithium deposition has not occurred; when the efficiency health change rate is less than the change rate threshold, determine that the lithium deposition detection result of the battery is that lithium deposition has occurred.

[0146] In a specific implementation of the embodiment of the present application, the value range of the change rate threshold may include [0, 0.1].

[0147] In a specific implementation of the embodiment of the present application, the battery lithium deposition detection device may further include:

[0148] The first threshold determination module is used to determine the efficiency health change rate of the sample battery in the charge and discharge test; wherein the model of the sample battery is consistent with the model of the battery; in the case that lithium deposition occurs in the sample battery, the efficiency health change rate corresponding to the lithium deposition of the sample battery is determined as the change rate threshold.

[0149] In a specific implementation of the embodiment of the present application, the battery lithium deposition detection device may further include:

[0150] The second threshold determination module is used to determine the change rate threshold corresponding to the battery according to the change rate threshold corresponding relationship; the change rate threshold corresponding relationship represents the corresponding relationship between the battery and the change rate threshold.

[0151] In a specific implementation of the embodiment of the present application, the parameter determination module may include:

[0152] The cycle energy efficiency determination unit is used to determine the charging energy of the battery in the charge and discharge test; determine the discharge energy of the battery in the charge and discharge test; and determine the cycle energy efficiency of the battery in the charge and discharge test based on the charging energy and the discharge energy.

[0153] In a specific implementation of the embodiment of the present application, the parameter determination module may include:

[0154] The health status determination unit is used to determine the current capacity of the battery during the charge and discharge test; and determine the health status of the battery during the charge and discharge test based on the current capacity and the rated capacity.

[0155] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described devices, modules and units can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0156] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0157] Figure 7 A schematic block diagram of a battery management system provided in an embodiment of the present application is shown. For ease of explanation, only the parts related to the embodiment of the present application are shown.

[0158] like Figure 7 As shown, the battery management system 7 of this embodiment includes: a processor 70, a memory 71, and a computer program 72 stored in the memory 71 and executable on the processor 70. When the processor 70 executes the computer program 72, the steps in the above-mentioned battery lithium deposition detection method embodiments are implemented, for example Figure 5 Alternatively, when the processor 70 executes the computer program 72, the functions of each module / unit in the above-mentioned device embodiments are realized, for example Figure 6 The functions of the parameter calculation module 601 to the lithium deposition detection module 603 are shown.

[0159] Exemplarily, the computer program 72 may be divided into one or more modules / units, one or more modules / units are stored in the memory 71, and executed by the processor 70 to complete the present application. One or more modules / units may be a series of computer program instruction segments capable of completing specific functions, and the instruction segments are used to describe the execution process of the computer program 72 in the battery management system 7.

[0160] Those skilled in the art will understand that Figure 7 It is only an example of the battery management system 7 and does not constitute a limitation of the battery management system 7. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the battery management system 7 may also include input and output devices, network access devices, buses, etc.

[0161] The processor 70 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.

[0162] The memory 71 may be an internal storage unit of the battery management system 7, such as a hard disk or memory of the battery management system 7. The memory 71 may also be an external storage device of the battery management system 7, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the battery management system 7. Further, the memory 71 may also include both an internal storage unit of the battery management system 7 and an external storage device. The memory 71 is used to store computer programs and other programs and data required by the battery management system 7. The memory 71 may also be used to temporarily store data that has been output or is to be output.

[0163] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0164] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0165] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0166] In the embodiments provided in the present application, it should be understood that the disclosed device / battery management system and method can be implemented in other ways. For example, the device / battery management system embodiments described above are merely schematic. For example, the division of modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0167] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0168] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0169] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable storage medium may include: any entity or device capable of carrying computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable storage medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable storage medium does not include electric carrier signals and telecommunication signals.

[0170] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A battery lithium deposition detection method, It is characterized in that include: determining a first cycle energy efficiency and a first state of health of the battery in a first charge and discharge test; The first charge and discharge test represents the previous charge and discharge test; determining a second cycle energy efficiency and a second health state of the battery in a second charge and discharge test; The second charge and discharge test represents a subsequent charge and discharge test; determining a cycle energy efficiency change between the second cycle energy efficiency and the first cycle energy efficiency; determining a change in health state between the second health state and the first health state; Determining the efficiency health change rate of the battery according to the cycle energy efficiency change and the health state change; The lithium plating detection result of the battery is determined according to the efficiency health change rate and the change rate threshold; the change rate threshold represents the critical value of the efficiency health change rate when lithium plating occurs in the battery.

2. The battery lithium deposition detection method according to claim 1, It is characterized in that Determining the lithium plating detection result of the battery according to the efficiency health change rate and the change rate threshold, including: When the efficiency health change rate is greater than or equal to the change rate threshold, it is determined that the lithium deposition detection result of the battery is that no lithium deposition occurs; When the efficiency health change rate is less than the change rate threshold, it is determined that the lithium plating detection result of the battery is that lithium plating has occurred.

3. The battery lithium deposition detection method according to claim 1, It is characterized in that The value range of the change rate threshold includes [0, 0.1].

4. The battery lithium deposition detection method according to claim 1, It is characterized in that Before determining the lithium plating detection result of the battery according to the efficiency health change rate and the change rate threshold, the method further includes: Determine the efficiency health change rate of the sample battery in the charge and discharge test; wherein the model of the sample battery is consistent with the model of the battery; In the case where lithium deposition occurs in the sample battery, the efficiency health change rate corresponding to the lithium deposition occurs in the sample battery is determined as the change rate threshold.

5. The battery lithium deposition detection method according to claim 1, It is characterized in that Before determining the lithium plating detection result of the battery according to the efficiency health change rate and the change rate threshold, the method further includes: According to the change rate threshold corresponding relationship, the change rate threshold corresponding to the battery is determined; the change rate threshold corresponding relationship represents the corresponding relationship between the battery and the change rate threshold.

6. The battery lithium deposition detection method according to any one of claims 1 to 5, It is characterized in that Determine the cycling energy efficiency of batteries in charge and discharge tests, including: Determining the charging energy of the battery in the charging and discharging test; Determining the discharge energy of the battery in the charge and discharge test; The cycle energy efficiency of the battery in the charge and discharge test is determined according to the charge energy and the discharge energy.

7. The battery lithium deposition detection method according to any one of claims 1 to 5, It is characterized in that Determine the health of the battery during charge and discharge tests, including: determining a current capacity of the battery during the charge and discharge test; The health status of the battery in the charge and discharge test is determined according to the current capacity and the rated capacity.

8. A battery lithium deposition detection device, It is characterized in that include: a rate of change determination module, configured to determine a first cycle energy efficiency and a first health state of a battery in a first charge and discharge test; The first charge and discharge test represents the previous charge and discharge test; Determining a second cycle energy efficiency and a second health state of the battery in a second charge and discharge test; the second charge and discharge test characterizing a subsequent charge and discharge test; determining a change in cycle energy efficiency between the second cycle energy efficiency and the first cycle energy efficiency; determining a change in health state between the second health state and the first health state; Determining the efficiency health change rate of the battery according to the cycle energy efficiency change and the health state change; A lithium plating detection module is used to determine the lithium plating detection result of the battery according to the efficiency health change rate and the change rate threshold; the change rate threshold represents the critical value of the efficiency health change rate when lithium plating occurs in the battery.

9. A computer-readable storage medium storing a computer program. It is characterized in that When the computer program is executed by a processor, the steps of the battery lithium deposition detection method as described in any one of claims 1 to 7 are implemented.

10. A battery management system comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, It is characterized in that When the processor executes the computer program, the steps of the battery lithium deposition detection method as described in any one of claims 1 to 7 are implemented.

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