Method and device for measuring self-discharge rate of lithium battery and readable storage medium

Abstract

The invention discloses a lithium battery self-discharge rate measurement method and device and a readable storage medium, and relates to the technical field of lithium battery detection, and the method comprises the steps: obtaining the charging capacity, the discharging capacity, the BMS power consumption capacity and the balance capacity of a lithium battery between two times of full charging; according to the charging capacity, the discharging capacity, the BMS power consumption capacity and the equalization capacity, calculating to obtain the self-discharging capacity of the lithium battery between the two times of full charging; and calculating the self-discharge rate of the lithium battery according to the self-discharge capacity. The method has the effect of improving the feasibility and accuracy of online calculation of the self-discharge rate of the lithium battery.

Description

Technical Field

[0001] The present application relates to the technical field of lithium battery detection, and in particular to a method and device for measuring the self-discharge rate of a lithium battery and a readable storage medium. Background Art

[0002] The self-discharge rate of a lithium battery refers to the rate of power loss when the lithium battery is not in use. Due to differences in lithium-ion battery raw material batches, production process deviations, operating conditions and other reasons, the self-discharge rates of different lithium batteries are inconsistent. The self-discharge rate of a lithium battery plays an important role in estimating the status of the BMS and evaluating the performance of the lithium battery.

[0003] At present, there are two main methods for calculating the self-discharge rate of lithium batteries: (1) Offline test method: A certain number of battery cells are selected in the laboratory, and are placed at a specific temperature and a specific initial SOC (State of Charge) for a certain period of time. Then, they are discharged at a constant current at 25°C. The remaining SOC after placement is calculated, and the difference between the SOC before and after placement is calculated, which is the self-discharge rate of the battery. This method requires a long period of static placement, and due to the inconsistency of lithium batteries, the specific test results of the battery cells selected in the laboratory cannot fully and accurately represent the characteristics of all lithium batteries. In addition, since the self-discharge rate of lithium batteries changes with the aging of lithium batteries, it is time-consuming and costly to test the self-discharge of the entire life cycle in the laboratory. (2) Online storage method: When the lithium battery is in the non-platform area of ​​the SOC-OCV (Open Circuit Voltage) curve (SOC < 25%) and meets the OCV correction conditions, the SOC0 is obtained by looking up the terminal voltage of the lithium battery at this time. After continuing to store for a certain period of time, the SOC1 is obtained by looking up the terminal voltage at this time. The difference in SOC before and after storage is calculated, and the power consumption of the BMS in this actual storage period is subtracted to finally obtain the self-discharge rate of the lithium battery. This method of online calculation of the self-discharge rate requires the lithium battery to be stored in the non-platform area for a long time, but in actual use conditions, the chances of meeting this condition are very small. Summary of the invention

[0004] The purpose of the present application is to solve at least one of the technical problems existing in the prior art, and to provide a method, device and readable storage medium for measuring the self-discharge rate of a lithium battery, so as to improve the feasibility and accuracy of online calculation of the self-discharge rate of a lithium battery.

[0005] In a first aspect, an embodiment of the present application provides a method for measuring the self-discharge rate of a lithium battery, which is applied to a battery management system connected to the lithium battery, and the method includes: Obtaining the charging capacity, discharging capacity, BMS power consumption capacity and balancing capacity of the lithium battery between two full charges; The self-discharge capacity of the lithium battery between the two full charges is calculated according to the charging capacity, the discharging capacity, the BMS power consumption capacity and the balancing capacity; The self-discharge rate of the lithium battery is calculated according to the self-discharge capacity.

[0006] According to the technical solution of the embodiment of the present application, at least the following beneficial effects are achieved: after the lithium battery is actually put into use, it often needs to undergo multiple charging and discharging processes, that is, multiple charging and discharging cycles. When the lithium battery is fully charged in the charging and discharging cycle, the SOC corresponding to the lithium battery is 100%. The charging capacity between two full charges is equal to the sum of the discharge capacity and other loss capacity. The other loss capacity mainly includes the BMS power consumption capacity, the balancing capacity and the self-discharge capacity. Therefore, by obtaining the charging capacity, the discharge capacity, the BMS power consumption capacity and the balancing capacity between two full charges, the self-discharge capacity of the lithium battery can be calculated and then the self-discharge rate of the lithium battery can be calculated. The lithium battery has more opportunities to be fully charged during normal use. Therefore, the calculation of the self-discharge rate of the lithium battery does not require long-term standing. , which greatly improves the feasibility of online calculation of self-discharge rate; in addition, since the basic calculation method of lithium battery self-discharge rate can be calculated by calculating the capacity consumption of lithium battery, therefore, obtaining the charging capacity parameters of lithium battery when fully charged to calculate the self-discharge rate can reduce the probability of self-discharge rate error caused by the error of charging capacity obtained when the battery SOC is not 100%, because the accuracy of battery management system in judging SOC as 100% is higher than that of judging SOC as other values, and even if the obtained charging capacity has an error, by obtaining the charging capacity of lithium battery when SOC is 100% twice when fully charged, that is, the parameters at the same state twice, the error of the obtained charging capacity can be reduced, and the accuracy of self-discharge rate calculation can be further improved.

[0007] According to some embodiments of the present application, the charging capacity is calculated by subtracting a first cumulative charging capacity corresponding to a first full charge of the two full charges from a second cumulative charging capacity corresponding to a second full charge of the two full charges.

[0008] According to some embodiments of the present application, the discharge capacity is calculated by subtracting the first cumulative discharge capacity corresponding to the first full charge of the two full charges from the second cumulative discharge capacity corresponding to the second full charge of the two full charges.

[0009] According to some embodiments of the present application, the BMS power consumption capacity is calculated based on the power consumption of the battery management system multiplied by the accumulated operating time of the battery management system between the two full charges.

[0010] According to some embodiments of the present application, the balancing capacity is calculated by multiplying the balancing current acquired by the battery management system by the balancing time recorded by the battery management system.

[0011] According to some embodiments of the present application, the self-discharge capacity is calculated by subtracting the discharge capacity, the BMS power consumption capacity and the balancing capacity from the charge capacity.

[0012] According to some embodiments of the present application, the self-discharge rate is calculated by dividing the self-discharge capacity by the total capacity of the lithium battery, and by the interval between the two full charges.

[0013] According to some embodiments of the present application, the interval between the two full charges is greater than 2 days and less than 7 days.

[0014] According to some embodiments of the present application, the temperature corresponding to the two full charges is greater than or equal to 20°C and less than or equal to 35°C.

[0015] According to some embodiments of the present application, the difference between the temperatures corresponding to the two full charges is less than or equal to 5°C.

[0016] According to some embodiments of the present application, the difference between the battery health status values ​​corresponding to the two full charges is less than or equal to 2%.

[0017] In a second aspect, an embodiment of the present application provides an operation control device, characterized in that it includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor executes the program to implement the method for measuring the self-discharge rate of a lithium battery as described in the first aspect above.

[0018] In a third aspect, an embodiment of the present application provides a battery management system, comprising the operation control device of the second aspect mentioned above.

[0019] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium storing computer-executable instructions, wherein the computer-executable instructions are used to enable a computer to execute the method for measuring the self-discharge rate of a lithium battery as described in the first aspect above.

[0020] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the structures specifically pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are used to provide further understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0022] The present application is further described below with reference to the accompanying drawings and embodiments; Figure 1 It is a flow chart of a method for measuring the self-discharge rate of a lithium battery provided in one embodiment of the present application; Figure 2 It is a schematic diagram of the internal structure of an operation control device for executing a method for measuring the self-discharge rate of a lithium battery provided in one embodiment of the present application. DETAILED DESCRIPTION

[0023] This section will describe in detail the specific embodiments of the present application. The preferred embodiments of the present application are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present application, but it cannot be understood as a limitation on the scope of protection of the present application.

[0024] In the description of the present application, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0025] In the description of this application, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0026] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0027] In some cases, the online measurement method of the self-discharge rate of a lithium battery is to obtain SOC0 by looking up the terminal voltage of the lithium battery at this time when the lithium battery is in the non-platform area of ​​the SOC-OCV curve and meets the conditions for OCV correction, and then continue to leave it for a certain period of time, and then obtain SOC1 by looking up the terminal voltage at this time, and calculate the difference in SOC before and after leaving it, and subtract the power consumption of the BMS in this actual leaving period, and finally obtain the self-discharge rate of the lithium battery; this method of online calculation of the self-discharge rate requires the lithium battery to be left in the non-platform area for a long time, and in actual usage conditions, the chances of meeting this condition are extremely small.

[0028] Based on the above situation, the embodiments of the present application propose a method, device, battery management system and readable storage medium for measuring the self-discharge rate of a lithium battery, aiming to improve the feasibility and accuracy of online calculation of the self-discharge rate of a lithium battery.

[0029] The following is combined with Figure 1-2 , various embodiments of the method for measuring the self-discharge rate of a lithium battery of the present application are further described.

[0030] like Figure 1 As shown, Figure 1 This is a flow chart of a method for measuring the self-discharge rate of a lithium battery provided in an embodiment of the present application. The method for measuring the self-discharge rate of a lithium battery is applied to a battery management system connected to a lithium battery. The method for measuring the self-discharge rate of a lithium battery may include but is not limited to step S110, step S120 and step S130.

[0031] Step S110, obtaining the charging capacity, discharging capacity, BMS power consumption capacity and balancing capacity of the lithium battery between two full charges; Step S120, calculating the self-discharge capacity of the lithium battery between two full charges according to the charging capacity, the discharging capacity, the BMS power consumption capacity and the balancing capacity; Step S130: Calculate the self-discharge rate of the lithium battery according to the self-discharge capacity.

[0032] In one embodiment, during the use and charging process of the lithium battery, the battery management system monitors the state of the lithium battery and obtains parameters including the voltage, current, and charge and discharge capacity of the lithium battery. Therefore, when the battery management system determines that the lithium battery has completed two full charges, the battery management system can obtain the charging capacity, discharge capacity, BMS power consumption capacity, and balancing capacity between the two full charges. The time between the two full charges can be the time between the two full charges, the time between the two full charges can also be the time between the battery capacity is fully charged, the time between the two full charges can also be the time between the two SOCs of 100%, and the time between the two full charges can also be the time between the two times when the open circuit voltage of the lithium battery reaches a specific relatively stable maximum value. The charging capacity of the lithium battery between two full charges can be the charging capacity calculated by the battery management system by directly collecting the current between the two full charges, or it can be the charging capacity indirectly calculated by monitoring the battery SOC change between the two full charges; The discharge capacity of a lithium battery between two full charges can be the discharge capacity calculated by the battery management system by directly collecting the current between the two full charges, or it can be the discharge capacity calculated indirectly by monitoring the battery SOC change between the two full charges; The BMS power consumption capacity of the lithium battery between two full charges can be calculated by the battery management system based on the time between two full charges combined with the pre-tested BMS power consumption; The equalization capacity of the lithium battery between two full charges can be calculated by the battery management system based on the time between the two full charges combined with the equalization current, wherein the equalization current is calculated by the collected cell voltage and the equalization resistance.

[0033] In one embodiment, obtaining the charging capacity, discharging capacity, BMS power consumption capacity and balancing capacity of the lithium battery between two full charges may be obtaining the charging capacity, discharging capacity, BMS power consumption capacity and balancing capacity between two times when the battery management system determines that the lithium battery is in a fully charged state. Determining that the lithium battery is in a fully charged state may be determining that the state parameters of the lithium battery meet a preset full charge condition. The preset full charge condition may include but is not limited to: (1) BMS is in charging state; (2) All monomer voltages are valid; (3) The maximum voltage does not reach the set full charge voltage value (for example, 3.65V); (4) The charging current is less than the set value (for example, 0.05C); When determining that the lithium battery is in a fully charged state, the battery may be determined to be in a fully charged state when one or more of the above conditions are met.

[0034] It is understandable that since the self-discharge rate is calculated based on the charge and discharge capacity of the lithium battery between two full charges, there is no specific requirement for the operating condition of the lithium battery between two full charges.

[0035] It can be understood that obtaining the charging capacity, discharging capacity, BMS power consumption capacity and balancing capacity of the lithium battery between two full charges may be obtaining the charging capacity, discharging capacity, BMS power consumption capacity and balancing capacity between two adjacent full charges, or may be obtaining the charging capacity, discharging capacity, BMS power consumption capacity and balancing capacity between two non-adjacent full charges; when obtaining the charging capacity, discharging capacity, BMS power consumption capacity and balancing capacity between two non-adjacent full charges, it may be between two adjacent determinations that the lithium battery is in a fully charged state, or between two adjacent determinations that the state parameters of the lithium battery meet the preset full charge conditions, that is, there may be a situation where the lithium battery is fully charged but the charging capacity, discharging capacity, BMS power consumption capacity and balancing capacity at this time are not obtained, that is, between two adjacent determinations that the lithium battery is in a fully charged state, the lithium battery may have been fully charged twice or more, and between two adjacent determinations that the state parameters of the lithium battery meet the preset full charge conditions, the lithium battery may also have been fully charged twice or more.

[0036] It can be understood that since it is necessary to obtain the parameters of the lithium battery between two full charges, when the battery management system determines that the lithium battery is in a fully charged state, it can be determined whether the current time the lithium battery is determined to be in a fully charged state is the first or second time. For example, the first full charge mark or the second full charge mark can be set when the lithium battery is determined to be in a fully charged state for the first time. The full charge mark refers to a mark that indicates that the battery management system has determined that the lithium battery is in a fully charged state. Therefore, when the battery management system determines that the lithium battery is in a fully charged state, it can retrieve whether the most recent full charge mark is the first full charge mark. If the most recent full charge mark can be retrieved as the first full charge mark, the second full charge mark can be set at present, so as to obtain the charging capacity, discharging capacity, BMS power consumption capacity and balancing capacity between the two full charges corresponding to the first full charge mark and the second full charge mark through the first full charge mark and the second full charge mark, thereby calculating the self-discharge rate; if the most recent full charge mark is retrieved as the second full charge mark or the first full charge mark cannot be retrieved, the first full charge mark can be set at present.

[0037] For example, when the battery management system determines that the lithium battery is fully charged, it determines whether the parameters of the lithium battery meet all of the following conditions: (1) BMS is in charging state; (2) All monomer voltages are valid; (3) The maximum voltage does not reach the set full charge voltage value (3.65V); (4) The charging current is less than the set value (0.05C); When it is determined that the parameters of the lithium battery meet all conditions, the full charge flag is set to 0; When it is determined next time that the lithium battery parameters meet all conditions, the full charge flag is set to 1, and the lithium battery parameters between the full charge flag 0 and the full charge flag 1 are obtained, that is, the charging capacity, discharging capacity, BMS power consumption capacity and balancing capacity of the lithium battery between two full charges.

[0038] It should be noted that there is no limitation on the method of determining whether the current time the lithium battery is determined to be in a fully charged state is the first or second time, and there is no limitation on the form of the full charge mark, as long as the battery management system can distinguish between the first time the lithium battery is in a fully charged state and the second time it is in a fully charged state.

[0039] In one embodiment, after obtaining the charging capacity, discharging capacity, BMS power consumption capacity and balancing capacity of the lithium battery between two full charges, the self-discharge capacity of the lithium battery between two full charges is calculated based on the charging capacity, discharging capacity, BMS power consumption capacity and balancing capacity, and then the self-discharge rate of the lithium battery is calculated based on the self-discharge capacity.

[0040] In one embodiment, the self-discharge rate of the lithium battery can be calculated based on the charge and discharge capacity difference between two full charges of the lithium battery, because the charge and discharge capacity difference between two full charges of the lithium battery can be obtained by calculating the sum of the charging capacity, the discharging capacity, the BMS power consumption capacity, the balancing capacity and the self-discharge capacity, wherein the charging capacity is a positive value, and the discharging capacity, the BMS power consumption capacity, the balancing capacity and the self-discharge capacity are negative values. Therefore, the self-discharge capacity can be obtained by the sum of the charging capacity, the discharging capacity, the BMS power consumption capacity and the balancing capacity, and then the self-discharge rate of the lithium battery is calculated based on the self-discharge capacity.

[0041] In one embodiment, the self-discharge rate can be estimated online based on the fact that the terminal voltage of the battery is consistent and the corresponding charge and discharge capacity difference is 0 at any two charging or discharging ends.

[0042] In the method for measuring the self-discharge rate of a lithium battery provided in some embodiments of the present application, the charging capacity is calculated by subtracting the first cumulative charging capacity corresponding to the first full charge of the two full charges from the second cumulative charging capacity corresponding to the second full charge of the two full charges.

[0043] It should be noted that the cumulative charging capacity refers to the total cumulative charging capacity of the lithium battery, among which the first cumulative charging capacity corresponding to the previous full charge may be the charging capacity accumulated at the time of the first full charge of the two full charges, and the second cumulative charging capacity corresponding to the second full charge may be the charging capacity accumulated at the time of the second full charge of the two full charges. Therefore, the second cumulative charging capacity corresponding to the second full charge is greater than the first cumulative charging capacity corresponding to the previous full charge. The charging capacity between the two full charges can be obtained by subtracting the first cumulative charging capacity corresponding to the previous full charge from the second cumulative charging capacity corresponding to the second full charge.

[0044] For example, the first cumulative charging capacity corresponding to the previous full charge is A, and the charging capacity between the two full charges between the previous full charge and the next full charge is B, then the second cumulative charging capacity corresponding to the next full charge is A+B. Conversely, the charging capacity B between the two full charges can be obtained by subtracting the first cumulative charging capacity A corresponding to the previous full charge from the second cumulative charging capacity A+B corresponding to the next full charge.

[0045] In the method for measuring the self-discharge rate of a lithium battery provided in some embodiments of the present application, the discharge capacity is calculated by subtracting the first cumulative discharge capacity corresponding to the first full charge of the two full charges from the second cumulative discharge capacity corresponding to the second full charge of the two full charges.

[0046] Specifically, the cumulative discharge capacity refers to the total cumulative discharge capacity of the lithium battery, wherein the first cumulative discharge capacity corresponding to the previous full charge may be the cumulative discharge capacity at the time of the first full charge of the two full charges, and the second cumulative discharge capacity corresponding to the second full charge may be the cumulative discharge capacity at the time of the second full charge of the two full charges. Therefore, the second cumulative discharge capacity corresponding to the second full charge is greater than the first cumulative discharge capacity corresponding to the previous full charge. The discharge capacity between the two full charges can be obtained by subtracting the first cumulative discharge capacity corresponding to the previous full charge from the second cumulative discharge capacity corresponding to the second full charge.

[0047] For example, the first cumulative discharge capacity corresponding to the previous full charge is A, and the discharge capacity between the two full charges between the previous full charge and the next full charge is B, then the second cumulative discharge capacity corresponding to the next full charge is A+B. Conversely, the discharge capacity B between the two full charges can be obtained by subtracting the first cumulative discharge capacity A corresponding to the previous full charge from the second cumulative discharge capacity A+B corresponding to the next full charge.

[0048] It should be noted that in the battery management system, if the cumulative discharge capacity and the cumulative charging capacity are statistically calculated through the change in the absolute value of the capacity, the cumulative discharge capacity may be expressed as a positive value, for example, 100mAh means that the cumulative discharge capacity is 100 mAh; and if the cumulative discharge capacity is statistically calculated through the outflow of the lithium battery discharge current and the cumulative charging capacity is statistically calculated through the inflow of the lithium battery charging current, the cumulative discharge capacity may be expressed as a negative value, for example, -100mAh means that the cumulative discharge capacity is 100 mAh.

[0049] In the lithium battery self-discharge rate measurement method provided in some embodiments of the present application, the BMS power consumption capacity is calculated based on the power consumption of the battery management system multiplied by the cumulative operating time of the battery management system between two full charges.

[0050] Specifically, the power consumption of the battery management system refers to the power consumption generated by the operation of the battery management system itself. In the present embodiment, the power consumption of the battery management system depends on the hardware design of the BMS. The power consumption of the battery management system can be obtained through advance testing. The power consumption of the battery management system can be the average power consumption of the battery management system. Therefore, the power consumption capacity of the BMS can be calculated by multiplying the power consumption of the battery management system by the cumulative operating time of the battery management system between two full charges.

[0051] It should be noted that the battery management system may not be running continuously between two full charges. When the battery management system is not running, the battery management system will not generate power consumption. Therefore, the BMS power consumption capacity can be obtained by multiplying the average power consumption of the battery management system by the cumulative operating time of the battery management system between two full charges.

[0052] It should be noted that the power consumption of the battery management system will not be included in the discharge capacity of the lithium battery. On the one hand, the battery management system can calculate the discharge capacity based on the discharge current of the lithium battery cell, and on the other hand, it can calculate the power consumption generated by its own operation. Therefore, when calculating the self-discharge capacity of the lithium battery, the discharge capacity and BMS power consumption capacity are calculated separately.

[0053] In the method for measuring the self-discharge rate of a lithium battery provided in some embodiments of the present application, the equalization capacity is calculated by multiplying the equalization current obtained by the battery management system by the equalization time recorded by the battery management system.

[0054] It is understandable that the battery management system usually has a battery balancing function, which can keep the power of each battery cell in the battery pack consistent. The activation time of the battery balancing function of the battery management system is usually determined by the BMS balancing control. When the battery management system turns on balancing, a balancing current will be generated. The balancing current can be calculated through the cell voltage and the balancing current resistance value. The corresponding balancing capacity can be obtained by multiplying the balancing current by the balancing time.

[0055] Specifically, between two full charges, the battery management system can record the length of time that balancing is turned on, that is, the balancing time, and the battery management system can simultaneously detect the cell voltage and the balancing current resistance when balancing is turned on, thereby calculating the balancing current through the cell voltage and the balancing current resistance, and then obtaining the balancing capacity by multiplying the balancing current by the balancing time.

[0056] In the method for measuring the self-discharge rate of a lithium battery provided in some embodiments of the present application, the self-discharge capacity is calculated by subtracting the discharge capacity, the BMS power consumption capacity and the balance capacity from the charge capacity.

[0057] It can be understood that the BMS power consumption capacity is the additional power consumption generated when the battery management system is running, and the balancing capacity is the additional capacity consumption generated by the battery management system to maintain the consistency of the power of each battery cell. Therefore, the discharge capacity calculated by the battery management system based on the directly collected discharge current does not include the BMS power consumption capacity and the balancing capacity, but the BMS power consumption capacity and the balancing capacity are also the capacity consumed by the lithium battery between two full charges, that is, between two full charges, the capacity consumed by the lithium battery includes the charging capacity, the BMS power consumption capacity and the balancing capacity, as well as the additional self-discharge capacity; Based on this, the self-discharge capacity can be obtained by subtracting the discharge capacity, BMS power consumption capacity and balancing capacity from the charge capacity.

[0058] In the method for measuring the self-discharge rate of a lithium battery provided in some embodiments of the present application, the self-discharge rate is calculated by dividing the self-discharge capacity by the total capacity of the lithium battery and by the interval between two full charges.

[0059] It can be understood that the basic calculation method of the self-discharge rate is to divide the self-discharge capacity by the total capacity of the lithium battery to obtain the self-discharge capacity ratio of the lithium battery, and then divide it by the interval between two full charges. Therefore, in this embodiment, the self-discharge rate is calculated by dividing the self-discharge capacity by the total capacity of the lithium battery and by the interval between two full charges.

[0060] In one embodiment, the unit of the self-discharge rate may be % / month, that is, the self-discharge rate of the lithium battery in a period of one month. The self-discharge rate may be calculated as follows: 100% *self-discharge capacity / total capacity of lithium battery / full charge interval time*30.

[0061] In the method for measuring the self-discharge rate of a lithium battery provided in some embodiments of the present application, the interval between two full charges is greater than 2 days and less than 7 days.

[0062] It is understood that lithium battery self-discharge refers to the phenomenon that the amount of electricity stored in the lithium battery decreases naturally without an external load. Under normal circumstances, the self-discharge rate of lithium batteries is usually slow. The self-discharge rate of lithium batteries refers to the rate at which the amount of electricity stored in the battery decreases naturally within a certain period of time without an external load. In addition, the self-discharge rate of lithium batteries is affected by many factors, including the use of lithium batteries; When it is necessary to test the self-discharge rate of a lithium battery, if the self-discharge rate of a lithium battery is tested within a short period of time, the self-discharge amount of the lithium battery is very small within the short period of time, and is affected by the use, discharge, storage conditions and charging conditions of the lithium battery; in addition, if the self-discharge rate of a lithium battery is tested within a long period of time, the lithium battery may undergo multiple cycles of charging within the long period of time, which will lead to a decrease in the accuracy of the self-discharge capacity measurement, and different storage states of the battery (such as full charge, half charge or empty charge) will affect the measurement of the self-discharge capacity of the lithium battery. That is, when it is necessary to measure the self-discharge rate of a lithium battery online, unlike the good environment without interference in the laboratory, there will be many factors that affect the measurement accuracy of the self-discharge capacity of the lithium battery after the lithium battery is actually put into use. Therefore, online measurement cannot be tested within a long period of time; In summary, when measuring the self-discharge rate of a lithium battery online, the time between two full charges needs to be controlled to improve the accuracy of the measured self-discharge rate of the lithium battery.

[0063] Based on this, when obtaining the charging capacity, discharging capacity, BMS power consumption capacity and equalizing capacity of the lithium battery between two full charges, you can first obtain the interval between the two full charges, and determine whether the interval between the two full charges is greater than 2 days and less than 7 days. If it is judged as no, you can pause the next step of calculating the self-discharge capacity of the lithium battery between the two full charges according to the charging capacity, discharging capacity, BMS power consumption capacity and equalizing capacity until the condition that the interval between the two full charges is greater than 2 days and less than 7 days is met. Then calculate the self-discharge capacity of the lithium battery. In other words, the interval between the two full charges being greater than 2 days and less than 7 days can be used as a condition for starting to calculate the self-discharge rate.

[0064] In the method for measuring the self-discharge rate of a lithium battery provided in some embodiments of the present application, the temperature corresponding to two full charges is greater than or equal to 20° C. and less than or equal to 35° C.

[0065] It is understandable that the temperature of the lithium battery is one of the important factors affecting the battery performance. The lithium battery can only work normally when the temperature of the lithium battery is within an appropriate range. Especially when charging, the temperature of the lithium battery will be higher than usual.

[0066] Based on this, when obtaining the charging capacity, discharging capacity, BMS power consumption capacity and equalizing capacity of the lithium battery between two full charges, the temperature of the lithium battery during the two full charges can be obtained first. The temperature of the lithium battery can be obtained through the monitoring of the battery management system to determine whether the temperature of the lithium battery during the two full charges is greater than or equal to 20°C and less than or equal to 35°C. If the judgment is no, the next step of calculating the self-discharge capacity of the lithium battery between the two full charges according to the charging capacity, discharging capacity, BMS power consumption capacity and equalizing capacity can be suspended until the condition that the temperature corresponding to the two full charges is greater than or equal to 20°C and less than or equal to 35°C is met, and then the self-discharge capacity of the lithium battery is calculated. That is to say, the temperature corresponding to the two full charges can be greater than or equal to 20°C and less than or equal to 35°C as a condition for starting to calculate the self-discharge rate.

[0067] In the method for measuring the self-discharge rate of a lithium battery provided in some embodiments of the present application, the difference between the temperatures corresponding to two full charges is less than or equal to 5°C.

[0068] It is understandable that controlling battery temperature is an important function of the battery management system. The battery management system can maintain the lithium battery within the optimal operating temperature range by controlling the battery heating or cooling system. The battery temperature is also one of the important factors in measuring the performance and health of the lithium battery. Within a certain period of time, the temperature fluctuation of a normal lithium battery during charging and discharging will not be too large. On the contrary, if the temperature fluctuation of the lithium battery during charging and discharging is large within a certain period of time, it means that the state of the lithium battery at this time is poor. If the self-discharge rate of the lithium battery is calculated at this time, the calculation result of the self-discharge rate will lead to inaccurate calculation result.

[0069] Based on this, when obtaining the charging capacity, discharging capacity, BMS power consumption capacity and equalizing capacity of the lithium battery between two full charges, the temperature of the lithium battery during the two full charges can be obtained first to determine whether the difference between the temperatures corresponding to the two full charges is less than or equal to 5°C. If the judgment is no, the next step of calculating the self-discharge capacity of the lithium battery between the two full charges according to the charging capacity, discharging capacity, BMS power consumption capacity and equalizing capacity can be suspended until the condition that the difference between the temperatures corresponding to the two full charges is less than or equal to 5°C is met, and then the self-discharge capacity of the lithium battery is calculated. In other words, the difference between the temperatures corresponding to the two full charges can be less than or equal to 5°C as a condition for starting to calculate the self-discharge rate.

[0070] In the method for measuring the self-discharge rate of a lithium battery provided in some embodiments of the present application, the difference between the battery health status values ​​corresponding to two full charges is less than or equal to 2%.

[0071] It is understandable that the battery health state (SOH) of a lithium battery is also one of the important factors for measuring the performance and health of a lithium battery. The battery health state of a lithium battery is usually expressed in percentage. When the battery health state of a lithium battery is 100%, the lithium battery is in the best working state. When the battery health state of a lithium battery is 0%, the lithium battery has completely failed. Within a certain period of time, the fluctuation degree of the battery health state of a normal lithium battery is small. On the contrary, if the battery health state of a lithium battery fluctuates greatly within a certain period of time, it means that the state of the lithium battery at this time is poor. If the self-discharge rate of the lithium battery is calculated at this time, the calculation result of the self-discharge rate will lead to inaccurate calculation result of the self-discharge rate.

[0072] Based on this, when obtaining the charging capacity, discharging capacity, BMS power consumption capacity and balancing capacity of the lithium battery between two full charges, the battery health status of the lithium battery during the two full charges can be obtained first, and it can be determined whether the difference between the battery health status corresponding to the two full charges is less than or equal to 2%. If the judgment is no, the next step of calculating the self-discharge capacity of the lithium battery between the two full charges according to the charging capacity, discharging capacity, BMS power consumption capacity and balancing capacity can be suspended until the condition that the difference between the battery health status corresponding to the two full charges is less than or equal to 2% is met, and then the self-discharge capacity of the lithium battery is calculated. In other words, the difference between the battery health status corresponding to the two full charges can be less than or equal to 2% as a condition for starting to calculate the self-discharge rate.

[0073] In one embodiment, (1) the interval between two full charges is greater than 2 days and less than 7 days; (2) The temperature corresponding to two full charges is greater than or equal to 20°C and less than or equal to 35°C; (3) The difference between the temperatures corresponding to two full charges is less than or equal to 5°C; (4) The difference between the battery health status corresponding to two full charges is less than or equal to 2%; The above conditions can all be used as conditions for starting to calculate the self-discharge rate. You can choose to start calculating the self-discharge rate when all the above conditions are met, or start calculating the self-discharge rate when one or more of the above conditions are met.

[0074] Based on the above-mentioned methods for measuring the self-discharge rate of lithium batteries in various embodiments, various embodiments of the operation control device, electronic device, computer-readable storage medium and computer program product of the present application are respectively proposed below.

[0075] like Figure 2 As shown, Figure 22 is a schematic diagram of an operation control device for executing a method for measuring the self-discharge rate of a lithium battery provided by an embodiment of the present application. The operation control device 200 implemented in the present application includes: a processor 220, a memory 210, and a computer program stored in the memory 210 and executable on the processor 220, such as executing Figure 1 The method steps S110 to S130, wherein: Figure 2 In the figure, a processor 220 and a memory 210 are taken as an example.

[0076] The processor 220 and the memory 210 may be connected via a bus or other means. Figure 2 The example of connecting through bus is taken in the following.

[0077] The memory 210, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer executable programs. In addition, the memory 210 may include a high-speed random access memory, and may also include a non-transitory memory, such as at least one disk storage device, a flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory 210 may optionally include a memory 210 remotely arranged relative to the processor 220, and these remote memories 210 may be connected to the operation control device 200 via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0078] Those skilled in the art will understand that Figure 2 The device structure shown in the figure does not constitute a limitation on the operation control device 200, and may include more or less components than shown in the figure, or combine certain components, or arrange the components differently.

[0079] exist Figure 2 In the operation control device 200 shown, the processor 220 can be used to call the control program stored in the memory 210, so as to implement the above-mentioned method for measuring the self-discharge rate of the lithium battery. Specifically, the non-transient software program and instructions required to implement the above-mentioned method for measuring the self-discharge rate of the lithium battery are stored in the memory 210. When executed by the processor 220, the above-mentioned method for measuring the self-discharge rate of the lithium battery is executed, for example, Figure 1 The method comprises steps S110 to S130.

[0080] It is worth noting that since the operation control device 200 of the embodiment of the present application can execute the lithium battery self-discharge rate measurement method of any of the above-mentioned embodiments, the specific implementation manner and technical effects of the operation control device 200 of the embodiment of the present application can refer to the specific implementation manner and technical effects of the lithium battery self-discharge rate measurement method of any of the above-mentioned embodiments.

[0081] In addition, an embodiment of the present application further provides a battery management system, which includes the operation control device 200 of the above embodiment.

[0082] It is worth noting that since the battery management system of the embodiment of the present application includes the operation control device of the above-mentioned embodiment, and the operation control device of the above-mentioned embodiment can execute the lithium battery self-discharge rate measurement method of any of the above-mentioned embodiments, therefore, the specific implementation methods and technical effects of the battery management system of the embodiment of the present application can refer to the specific implementation methods and technical effects of the lithium battery self-discharge rate measurement method of any of the above-mentioned embodiments.

[0083] In addition, an embodiment of the present application further provides a computer-readable storage medium, which stores computer-executable instructions, and the computer-executable instructions are used to execute the above-mentioned lithium battery self-discharge rate measurement method. Figure 1 The method steps in .

[0084] It is worth noting that since the computer-readable storage medium of the embodiment of the present application can execute the method for measuring the self-discharge rate of a lithium battery in any of the above-mentioned embodiments, the specific implementation manner and technical effects of the computer-readable storage medium of the embodiment of the present application can refer to the specific implementation manner and technical effects of the method for measuring the self-discharge rate of a lithium battery in any of the above-mentioned embodiments.

[0085] It will be appreciated by those skilled in the art that all or some of the steps and systems in the disclosed methods above may be implemented as software, firmware, hardware and appropriate combinations thereof. Some physical components or all physical components may be implemented as software executed by a processor, such as a central processing unit, a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium or a non-transitory medium and a communication medium or a temporary medium. As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information such as computer-readable instructions, data structures, program modules or other data. Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disk DVD or other optical disk storage, magnetic cassettes, magnetic tapes, disk storage or other magnetic storage devices, or any other medium that may be used to store desired information and may be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically embodies computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0086] In several embodiments provided in the present application, it should be understood that the disclosed systems, apparatuses and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely schematic, for example, the division of units is only a logical function division, and 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 apparatuses or units, which can be electrical, mechanical or other forms. The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the scheme of this embodiment.

[0087] It should also be understood that the various implementations provided in the embodiments of the present application can be combined arbitrarily to achieve different technical effects.

[0088] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in the technical field without departing from the purpose of the present application.

Claims

1. A method for measuring the self-discharge rate of a lithium battery, characterized in that: Applied to a battery management system connected to the lithium battery, the method comprises: Obtaining the charging capacity, discharging capacity, BMS power consumption capacity and balancing capacity of the lithium battery between two full charges; The self-discharge capacity of the lithium battery between the two full charges is calculated according to the charging capacity, the discharging capacity, the BMS power consumption capacity and the balancing capacity; The self-discharge rate of the lithium battery is calculated according to the self-discharge capacity.

2. The measuring method according to claim 1, characterized in that: The charging capacity is calculated by subtracting a first accumulated charging capacity corresponding to a first full charge of the two full charges from a second accumulated charging capacity corresponding to a second full charge of the two full charges.

3. The measuring method according to claim 1, characterized in that: The discharge capacity is calculated by subtracting a first accumulated discharge capacity corresponding to a first full charge of the two full charges from a second accumulated discharge capacity corresponding to a second full charge of the two full charges.

4. The measuring method according to claim 1, characterized in that: The BMS power consumption capacity is calculated according to the power consumption of the battery management system multiplied by the accumulated operation time of the battery management system between the two full charges.

5. The measuring method according to claim 1, characterized in that: The balancing capacity is calculated according to the balancing current acquired by the battery management system multiplied by the balancing time recorded by the battery management system.

6. The measuring method according to any one of claims 1 to 5, characterized in that: The self-discharge capacity is calculated by subtracting the discharge capacity, the BMS power consumption capacity and the balancing capacity from the charge capacity.

7. The measuring method according to any one of claims 1 to 5, characterized in that: The self-discharge rate is calculated by dividing the self-discharge capacity by the total capacity of the lithium battery and by the interval between the two full charges.

8. The measuring method according to any one of claims 1 to 5, characterized in that: The interval between the two full charges is greater than 2 days and less than 7 days.

9. The measuring method according to any one of claims 1 to 5, characterized in that: The temperature corresponding to the two full charges is greater than or equal to 20° C. and less than or equal to 35° C.

10. The measuring method according to any one of claims 1 to 5, characterized in that: The difference between the temperatures corresponding to the two full charges is less than or equal to 5°C.

11. The measuring method according to any one of claims 1 to 5, characterized in that: The difference between the battery health status values ​​corresponding to the two full charges is less than or equal to 2%.

12. An operation control device, characterized in that: It comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method for measuring the self-discharge rate of a lithium battery as claimed in any one of claims 1 to 11.

13. A battery management system, characterized in that: Includes the operation control device as claimed in claim 12.

14. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to enable a computer to execute the method for measuring the self-discharge rate of a lithium battery as described in any one of claims 1 to 11.

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