Battery life prediction method and electronic equipment

Abstract

The invention provides a battery life prediction method and electronic equipment, and the method comprises the steps: determining the current reference battery capacity corresponding to n according to a preset first corresponding relation between the number n of cycles of a battery and the reference battery capacity if a preset condition is satisfied in the nth charge-discharge cycle of the battery; according to the difference delta between the current reference battery capacity and the current real capacity, whether the first corresponding relation is updated or not is judged. And if the first corresponding relation is updated, determining the number of life end cycles of the battery according to the updated first corresponding relation, otherwise, determining the number of life end cycles of the battery according to the first corresponding relation which is not updated. Therefore, according to the battery life prediction method and the electronic equipment provided by the invention, the first corresponding relation curve can be corrected according to different use environments, so that the accuracy of battery life prediction is improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery life prediction method and electronic equipment. Background Art

[0002] With the development of battery technology, lithium batteries have been more widely used. Among them, the life prediction of lithium batteries is of great significance to users. The life prediction of lithium batteries is usually calculated and obtained based on the relationship curve between the number of charge and discharge cycles and the battery capacity of the lithium battery. However, the relationship curve between the number of charge and discharge cycles and the battery capacity of the same model of lithium batteries in different usage environments is different. Therefore, how to accurately predict the life of lithium batteries based on the usage environment of lithium batteries has become an urgent problem to be solved. Summary of the invention

[0003] In view of the above problems, the present application provides a battery life prediction method and an electronic device.

[0004] In a first aspect, the present application provides a battery life prediction method, the method comprising: in the nth charge and discharge cycle of the battery, if the preset conditions are met, according to the preset first correspondence between the number of cycles n of the battery and the reference battery capacity, determine the current reference battery capacity corresponding to n, wherein n is a positive integer. According to the difference delta between the current reference battery capacity and the current true capacity, determine whether to update the first correspondence. If the first correspondence is updated, the number of cycles at which the battery's life ends is determined according to the updated first correspondence, otherwise the number of cycles at which the battery's life ends is determined according to the unupdated first correspondence. The present application determines whether to update the preset first corresponding relationship according to the difference delta between the current reference battery capacity and the current true capacity, so that the first corresponding relationship curve can be corrected according to different usage environments, thereby improving the accuracy of the battery life prediction.

[0005] In conjunction with the first aspect, in a possible implementation, satisfying a preset condition includes: a pre-stored abnormality mark value N is a first value and n is a multiple of a preset interval number, or the abnormality mark value N is greater than the first value.

[0006] In combination with the first aspect, in a possible implementation manner, the first corresponding relationship is a polynomial function of the cycle number n of the battery and the reference battery capacity, and updating the first corresponding relationship includes: updating a linear term coefficient of the polynomial function.

[0007] In combination with the first aspect, in a possible implementation method, whether to update the first corresponding relationship is determined based on the difference delta between the current reference battery capacity and the current actual capacity, including: if delta is greater than or equal to the minimum value of the preset interval, and less than or equal to the maximum value of the preset interval, based on the comparison result of delta with multiple preset interval endpoint values, whether to update the first corresponding relationship is determined, and whether to reset the abnormal mark value N to the first value, wherein the multiple preset interval endpoint values ​​are all greater than or equal to the minimum value of the preset interval, and less than or equal to the maximum value of the preset interval.

[0008] In combination with the first aspect, in a possible implementation, a preset interval is determined by a preset interval minimum value and a preset interval maximum value, a plurality of preset interval endpoint values ​​divide the preset interval into a plurality of preset sub-intervals, each preset sub-interval corresponds to a compensation value, the plurality of preset sub-intervals include a zero compensation interval and a non-zero compensation interval, and judging whether to update the first corresponding relationship based on the comparison result of delta with the plurality of preset interval endpoint values ​​includes: determining the preset sub-interval in which delta is located based on the comparison result of delta with the plurality of preset interval endpoint values. If delta is located in the zero compensation interval, the first corresponding relationship is not updated. If delta is located in the non-zero compensation interval, the coefficient of the first-order term of the polynomial function is increased by the corresponding compensation value to update the first corresponding relationship.

[0009] In combination with the first aspect, in a possible implementation method, whether to update the first corresponding relationship is determined based on the difference delta between the current reference battery capacity and the current actual capacity, including: if delta is less than the minimum value of the preset interval, or greater than the maximum value of the preset interval, the abnormal mark value N is increased by one, and whether to update the first corresponding relationship is determined based on the abnormal mark value.

[0010] In combination with the first aspect, in a possible implementation, determining whether to update the first correspondence relationship according to the abnormal mark value N includes: if the abnormal mark value N is a second value, obtaining a correction coefficient dn, and updating the coefficient of the first term of the polynomial function as the correction coefficient to update the first correspondence relationship, and resetting the abnormal mark value N to a first value, wherein the second value is greater than the first value. If the abnormal mark value N is greater than the first value and less than the second value, the first correspondence relationship is not updated.

[0011] In combination with the first aspect, in a possible implementation, the correction coefficient dn satisfies: , where R is the current real capacity, a, b, c, e are the coefficients of the fourth-order term, the third-order term, the second-order term, and the zero-order term of the polynomial function, respectively, and x is the current number of cycles.

[0012] In combination with the first aspect, in a possible implementation, the method further includes: in the nth charge and discharge cycle of the battery, if n does not meet a preset condition, controlling the battery to complete the nth charge and discharge cycle and enter the n+1th cycle.

[0013] In combination with the first aspect, in a possible implementation, determining the number of cycles before the battery's life ends includes: if a derivative of the polynomial function at at least one cycle number is greater than a preset threshold, taking the minimum value of at least one cycle number as the number of cycles before the battery's life ends.

[0014] In combination with the first aspect, in a possible implementation, in the nth charge and discharge cycle of the battery, if the preset conditions are met, before determining the current reference battery capacity corresponding to n based on the preset first correspondence between the number of cycles of the battery and the reference battery capacity, the method also includes: in the process of the battery being charged and discharged from zero cycles to the battery capacity being less than the preset capacity, collecting the battery capacities corresponding to multiple cycle numbers, and fitting to obtain the first correspondence.

[0015] In a second aspect, the present application provides an electronic device, the electronic device including a battery management system, the battery management system being used to execute the battery life prediction method provided by any possible implementation of the first aspect above. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of a first corresponding relationship curve of lithium batteries of the same model under different usage environments according to an embodiment of the present application.

[0017] Figure 2 A schematic diagram of a battery provided in accordance with an embodiment of the present application.

[0018] Figure 3 A flowchart of a battery life prediction method provided in one embodiment of the present application.

[0019] Figure 4 for Figure 3 Flowchart of step S33 in FIG.

[0020] Figure 5 for Figure 4 Flowchart of step S46 in FIG.

[0021] Figure 6 Another flow chart of a battery life prediction method provided in an embodiment of the present application.

[0022] Figure 7 A schematic diagram of a first corresponding relationship after updating of a battery life prediction method provided in an embodiment of the present application.

[0023] Figure 8A schematic diagram of the error of the first corresponding relationship after updating of the battery life prediction method provided in one embodiment of the present application. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application.

[0025] It is understandable that the connection relationship described in this application refers to direct or indirect connection. For example, the connection between A and B can be either a direct connection between A and B or an indirect connection between A and B through one or more other electrical components. For example, A and C can be directly connected, and C and B can be directly connected, so that A and B are connected through C. It is also understandable that the "A connects B" described in this application can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components.

[0026] In the description of this application, unless otherwise specified, " / " means "or", for example, A / B can mean A or B. "And / or" in this article is only a way to describe the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0027] In the description of this application, words such as "first" and "second" are only used to distinguish different objects, and do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit differences. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0028] With the development of battery technology, lithium batteries have been more widely used. Among them, the life prediction of lithium batteries is of great significance to users. The life prediction of lithium batteries is usually calculated and obtained based on the first corresponding relationship curve between the preset number of charge and discharge cycles of the lithium battery and the battery capacity. However, the first corresponding relationship curve is different for the same model of lithium batteries in different usage environments, such as Figure 1 As shown, in two different usage scenarios, the relationship curves between the number of charge and discharge cycles and the battery capacity of the same type of lithium battery are different. Therefore, how to accurately predict the life of the lithium battery according to the usage environment of the lithium battery has become an urgent problem to be solved.

[0029] Therefore, the present application provides a battery life prediction method and a battery, which can correct the first corresponding relationship curve of the battery according to different usage environments, thereby improving the accuracy of battery life prediction.

[0030] See also Figure 2 , Figure 2Schematic diagram of an electronic device 10 provided in the present application. In one embodiment of the present application, the electronic device 10 is a battery, specifically, the battery 10 includes a battery management system 11 and a battery cell module 12. In other embodiments, the electronic device 10 is a terminal, such as a mobile phone, a tablet, etc., and the battery management system 11 is provided in the terminal outside the battery.

[0031] The battery cell module 12 is used to output electrical energy to supply power to the load. The battery cell module 12 may include one battery cell, or more than two battery cells. When the battery cell module 12 includes more than two battery cells, the two or more battery cells may be connected in series, in parallel, in mixed connection, etc., and the present application does not impose any restrictions on the number of battery cells included in the battery cell module 12 and their connection methods. The load may include electrical equipment, energy storage equipment, and other equipment that receives electrical energy, such as terminal equipment, batteries, inverters, etc. The present application does not impose any restrictions on the type of load.

[0032] The battery management system 11 is electrically connected to the cell module 12. The battery management system 11 is used to detect the parameters of the cell module 12 and control the cell module 12 accordingly. For example, the battery management system 11 can adjust the output voltage, output current, output power, etc. of the cell module 12 by detecting the output voltage, output current, output power, temperature and other parameters of the cell module 12. For another example, the battery management system 11 can adjust the charging state or discharge state of the cell module 12 by detecting the state of charge, charging or discharging voltage, charging or discharging current, temperature, number of cycles and other parameters of the cell module 12 during the charging or discharging process. The charging state includes charging mode, charging parameters and the like. The charging mode includes one of the charging modes such as constant current charging, constant voltage charging, constant power charging, or different combinations of the above charging modes. The charging parameters include one of the parameters such as charging start voltage, charging start current, charging cut-off voltage, charging cut-off current, charging start state of charge, charging cut-off state of charge, or different combinations of the above parameters. Similarly, the discharge state is similar to the charging state and will not be repeated here.

[0033] See also Figure 3 , Figure 3 This is a flow chart of the battery life prediction method provided in this application. The battery life prediction method can be executed by the battery management system 11. The battery life prediction method includes the following steps.

[0034] Step S31, determining whether the state of the battery 10 satisfies a preset condition.

[0035] If the judgment result is yes, then execute step S32. If the judgment result is no, then execute step S36.

[0036] Among them, satisfying the preset condition may include that the abnormality mark value N pre-stored in the battery management system 11 is a first value and the current cycle number n of the battery 10 is a multiple of the preset interval number. Satisfying the preset condition may also include that the abnormality mark value N is greater than the first value. In some embodiments, the first value is 0 and the preset interval number is 10.

[0037] In some embodiments, the cycle number n of the battery 10 is pre-stored in a fuel gauge chip in the battery management system 11. Therefore, the current cycle number n of the battery 10 can be obtained by reading the cycle number n in the fuel gauge chip.

[0038] In some embodiments, the abnormality mark value is used to indicate an abnormal condition of the battery 10, and the battery management system 11 can change the pre-stored abnormality mark value according to the charge and discharge conditions of the battery 10. The larger the abnormality mark value N is, the more cycles that indicate the abnormal condition of the battery 10 are accumulated. That is, when the abnormality mark value N is a first value, it indicates that the battery 10 is not in an abnormal condition. When the abnormality mark value N is greater than the first value, it indicates that the battery 10 has an abnormal condition.

[0039] In this way, since the battery 10 is not in an abnormal condition and step S32 is executed only at multiples of the preset interval number, the number of executions of the battery life prediction method can be reduced, resource usage can be reduced, and efficiency can be improved. In addition, when the battery 10 has an abnormal condition, it is not restricted by the current cycle number being a multiple of the preset interval number, and the life prediction of the battery 10 can be performed in time in response to the abnormal condition of the battery 10, thereby enhancing the dynamic adaptability of the battery life prediction method.

[0040] Step S32 , determining a current reference battery capacity corresponding to the current cycle number n of the battery 10 according to a preset first corresponding relationship between the cycle number n of the battery 10 and the reference battery capacity.

[0041] The first corresponding relationship may be pre-stored in the battery management system 11, or may be obtained by performing a charge and discharge cycle experiment on the battery 10 or a battery of the same model as the battery 10. Specifically, the current cycle number n of the battery 10 may be matched with the cycle number in the first corresponding relationship, and the reference battery capacity corresponding to the matched cycle number may be used as the current reference battery capacity.

[0042] In some embodiments, the first corresponding relationship is a polynomial function of the cycle number n of the battery 10 and the reference battery capacity, wherein the polynomial function can be represented by the following formula (1).

[0043] e (1) Wherein, x is the number of cycles of battery 10, is the reference battery capacity of the battery 10. a is the coefficient of the nth order term in the polynomial function, b is the coefficient of the n-1th order term, c is the coefficient of the n-2nd order term, and so on, d is the coefficient of the 1st order term, and e is a constant.

[0044] Step S33, judging whether to update the first corresponding relationship according to the difference delta between the current reference battery capacity and the actual capacity.

[0045] If the judgment result is yes, then execute step S34. If the judgment result is no, then execute step S35.

[0046] In some embodiments, the real capacity of the battery 10 can be calculated by real-time detection of the fuel gauge chip. Therefore, the real capacity of the battery 10 can be obtained by reading the real capacity in the fuel gauge chip.

[0047] In some embodiments, updating the first corresponding relationship may include updating the coefficient of the first-order term in formula (1), for example, updating d in formula (1). However, the present application does not impose any limitation on the specific method of updating formula (1).

[0048] In this way, the reference battery capacity corresponding to the current cycle number n of the battery 10 can be obtained according to the preset first correspondence, and according to the difference between the actual capacity and the current reference battery capacity, it is determined whether to update the first correspondence, so that the life prediction of the battery 10 can be adapted to different usage environments, thereby improving the compatibility and accuracy of the battery life prediction method in different usage environments.

[0049] Step S34, determining the end-of-life cycle number of the battery according to the updated first corresponding relationship.

[0050] In some embodiments, the end-of-life cycle number of the battery may be the cycle number corresponding to a sharp decrease in the battery capacity of the battery. Therefore, the cycle number on the curve of the first corresponding relationship that meets the preset conditions can be obtained through the curve diagram of the first corresponding relationship. If multiple cycle numbers meet the preset conditions, the minimum value among the multiple cycle numbers is used as the end-of-life cycle number of the battery.

[0051] Therefore, after the first corresponding relationship is updated, the end-of-life cycle number of the battery can be obtained according to the curve diagram of the updated first corresponding relationship.

[0052] Step S35, determining the end-of-life cycle number of the battery according to the first corresponding relationship that has not been updated.

[0053] When the first corresponding relationship is not updated, the end-of-life cycle number of the battery can be obtained according to the curve diagram of the first corresponding relationship that has not been updated.

[0054] Specifically, obtaining the end-of-life cycle number of the battery according to the curve diagram of the updated or unupdated first corresponding relationship may include: obtaining the derivative of the polynomial function of the updated or unupdated first corresponding relationship, and taking the minimum value of the cycle number that meets the preset condition as the end-of-life cycle number of the battery 10. The preset condition may be met when the derivative is greater than the cycle number corresponding to the preset threshold.

[0055] In this way, when the derivative at a specific cycle number is greater than a preset threshold, it indicates that the battery capacity of the battery 10 drops sharply at the specific cycle number, and thus the minimum value of all cycle numbers that meet the preset conditions can be used as the end-of-life cycle number of the battery 10.

[0056] Step S36, controlling the battery 10 to complete the current charge and discharge cycle and enter the next cycle.

[0057] If the state of the battery 10 does not meet the preset condition, the battery 10 is controlled to enter the next charge and discharge cycle after completing the current charge and discharge cycle normally, that is, the number of cycles of the battery 10 is increased by 1. Then, the process returns to step S31 to determine whether the state of the battery 10 meets the preset condition again, and so on.

[0058] In some embodiments, before step S31, the battery life prediction method provided by the present application may further include step S30, obtaining a first corresponding relationship. Wherein, obtaining the first corresponding relationship may specifically include: in the process of charging and discharging the same type of battery 10 from zero cycle number to the battery capacity of the battery being less than a preset capacity, collecting the battery capacities corresponding to a plurality of cycle numbers, and fitting to obtain the first corresponding relationship.

[0059] Specifically, obtaining the first corresponding relationship may include the following steps.

[0060] Step 1: charging an experimental battery of the same type as battery 10 at a preset temperature until a charging cut-off condition is met.

[0061] The preset temperature may be room temperature, for example, 25°C. The number of cycles of the experimental battery before executing step 1 is zero. That is, the experimental battery has not undergone a charge and discharge cycle before executing step 1. The same model battery of battery 10 may be a battery having the same size, electrochemical system, electrical performance parameters, etc. as battery 10, wherein the size may include the battery's outer dimensions, thickness, width, and length, etc., the electrochemical system may include the type and ratio of positive and negative electrode materials, the type of electrolyte, etc., and the electrical performance parameters may include battery capacity, voltage range, internal resistance, charge and discharge rate, etc.

[0062] Among them, the charging method for charging the experimental battery can be constant current charging, constant voltage charging, constant current charging followed by constant voltage charging, etc. Constant current charging is used as an example for explanation, but the present application does not impose any limitation on the charging method of the experimental battery 10. In some embodiments, the charging current of the constant current charging of the experimental battery can be 0.2C.

[0063] Wherein, satisfying the charging cut-off condition may include that the voltage of the experimental battery reaches the charging cut-off voltage. In some embodiments, the charging cut-off voltage is related to the number of battery cell strings of the experimental battery. Wherein, the experimental battery may include a plurality of battery cells, and the plurality of battery cells may be connected in parallel to each other to form a battery cell string, thereby increasing the battery capacity of the experimental battery. A plurality of battery cell strings may be connected in series to increase the voltage of the experimental battery. That is, the voltage of the experimental battery and the charging cut-off voltage are determined based on the voltages of the plurality of battery cell strings and the charging cut-off voltage. For example, the experimental battery may include 4 battery cell strings, and the charging cut-off voltage of each battery cell string is 4.5V, then the charging cut-off voltage of the experimental battery is 18V.

[0064] Step 2: Leave the experimental battery to stand for a preset time.

[0065] In order to reduce the polarization of the experimental battery, extend the battery life, and improve the accuracy of the experimental battery parameter detection, the experimental battery can be left to stand for a preset time after each charging or discharging cycle. In some embodiments, the preset time can be 2 hours.

[0066] Step 3: Discharge the experimental battery at a preset temperature until a discharge cut-off condition is met.

[0067] The discharge method for discharging the experimental battery may be constant current discharge. In some embodiments, the discharge current of the constant current discharge of the experimental battery may be 0.2C.

[0068] Wherein, satisfying the discharge cut-off condition may include that the voltage of the experimental battery reaches the discharge cut-off voltage. In some embodiments, similar to the charge cut-off voltage, the discharge cut-off voltage of the experimental battery is determined according to the discharge cut-off voltages of multiple battery cell strings. For example, the experimental battery may include 4 battery cell strings, and the discharge cut-off voltage of each battery cell string is 3V, then the discharge cut-off voltage of the experimental battery is 12V.

[0069] Step 4: Leave the experimental battery to stand for a preset time.

[0070] Step 5, collecting the current battery capacity of the experimental battery, and determining whether the current battery capacity is less than or equal to the preset capacity.

[0071] If the judgment result is yes, the charge and discharge cycle of the experimental battery is terminated and step 7 is executed; otherwise, step 6 is executed.

[0072] The preset capacity may be 0. If the battery capacity is less than or equal to the preset capacity, it indicates that the life of the experimental battery has expired. At this point, the charge and discharge cycle of the experimental battery can be terminated.

[0073] Step 6: Use the current battery capacity as the reference battery capacity corresponding to the current number of cycles.

[0074] After executing step 6, the experimental battery enters the next charge and discharge cycle and returns to step 1. Similarly, the reference battery capacity corresponding to each cycle number can be obtained.

[0075] In some embodiments, in order to reduce the amount of measured data and improve the efficiency of the method for obtaining the first corresponding relationship, step 6 may be performed every preset number of cycles. When the number of cycles of step 6 is not performed, step 5 is performed and after the judgment result is no, the next charge and discharge cycle is entered and step 1 is returned to be executed. For example, the preset number of cycles may be 5, and when the number of cycles is 1, 6, and 11, the corresponding current battery capacity is measured and obtained respectively, thereby obtaining the number of cycles 1, 6, and 11 and their corresponding reference battery capacities.

[0076] Step 7: Obtain a first corresponding relationship according to a plurality of cycle numbers and their corresponding reference battery capacities.

[0077] The functional relationship corresponding to the first corresponding relationship can be obtained by fitting multiple cycle numbers and their corresponding reference battery capacities. The fitting method can be polynomial fitting, linear fitting, Fourier series fitting, etc. Here, polynomial fitting based on the least squares method is used as an example for explanation, but this application does not limit the fitting method in any way.

[0078] In some embodiments, a polynomial function corresponding to the first correspondence relationship can be obtained by polynomial fitting, for example, the functional relationship shown in formula (1). Since batteries of the same model have the same first correspondence relationship, the first correspondence relationship obtained by the experimental battery charge and discharge cycle experiment can be used as the first correspondence relationship of the battery 10.

[0079] See also Figure 4 , Figure 4 This is a flow chart of step S33 in the battery life prediction method provided in this application. Step S33 may specifically include the following steps.

[0080] Step S41, determining whether delta is greater than or equal to a minimum value of a preset interval and less than or equal to a maximum value of a preset interval.

[0081] If the judgment result is yes, execute step S42, otherwise execute step S46.

[0082] The preset interval minimum value and the preset interval maximum value determine a preset interval, and the preset interval is used to characterize the degree of deviation between the current reference battery capacity and the actual capacity. For example, when delta is greater than or equal to the preset interval minimum value, and less than or equal to the preset interval maximum value, that is, when delta falls within the preset interval determined by the preset interval minimum value and the preset interval maximum value, it characterizes that the degree of deviation between the current reference battery capacity and the actual capacity is small. In some embodiments, the preset interval minimum value is -100, and the preset interval maximum value is 100.

[0083] Step S42, determining the preset sub-interval in which delta is located according to the comparison result of delta and the endpoint values ​​of multiple preset intervals.

[0084] Among them, the preset interval includes multiple preset interval endpoint values, and the multiple preset interval endpoint values ​​divide the preset interval into multiple preset sub-intervals, and the multiple preset sub-intervals include a zero compensation interval and a non-zero compensation interval. For example, the multiple preset interval endpoint values ​​include -50, -25, 25, and 50, and the multiple preset sub-intervals are [-100, -50), (-50, -25), (-25, 25), (25, 50), and (50, 100). After comparing delta with the multiple preset interval endpoint values, the preset sub-interval where delta is located can be obtained. For example, when delta is greater than -25 and delta is less than 25, the preset sub-interval where delta is located is (-25, 25).

[0085] Step S43, determining whether delta is in the zero compensation interval.

[0086] If the judgment result is yes, execute step S44, otherwise execute step S45.

[0087] Among them, each preset sub-interval corresponds to a compensation value, and there are zero compensation intervals and non-zero compensation intervals in multiple preset sub-intervals, wherein the compensation value corresponding to the zero compensation interval is 0, and the compensation value corresponding to the non-zero compensation interval is not 0. The compensation value is used to characterize the correction or update amplitude of the first corresponding relationship. The larger the absolute value of the compensation value, the larger the amplitude of the correction or update of the first corresponding relationship. When the compensation value is 0, it indicates that there is no need to correct or update the first corresponding relationship. For example, the compensation values ​​corresponding to each of the above preset sub-intervals can be -0.02, -0.01, 0, 0.01, and 0.02, respectively.

[0088] Step S44: do not update the first corresponding relationship, and reset the abnormal flag value N to the first value.

[0089] After determining whether to update the first corresponding relationship, the abnormal flag value N is reset to the first value to restore the abnormal state of the battery 10. After executing step S44, the determination result of step S33 is no, and step S35 is continued.

[0090] Step S45, updating the first corresponding relationship, and resetting the abnormal flag value N to the first value.

[0091] In some embodiments, updating the first correspondence may include increasing the coefficient of the first-order term of the polynomial function in the first correspondence by the corresponding compensation value. For example, if the coefficient of the first-order term in formula (1) is d, the updated first correspondence is as shown in the following formula (2).

[0092] (2) Where D is the coefficient of the first term of the polynomial function in the updated first correspondence. D is the compensation value corresponding to d. For example, when delta is in the interval (50,100], since the compensation value corresponding to the interval (50,100] is 0.02, D = d + 0.02.

[0093] Step S46, increasing the abnormal mark value N by one, and determining whether to update the first corresponding relationship according to the abnormal mark value.

[0094] Among them, the initial value of the abnormal mark value N can be the first value. Since step S46 is a subsequent step executed when the judgment result of step S41 is no, that is, at this time, delta is less than the minimum value of the preset interval, or greater than the maximum value of the preset interval. When delta falls within the preset interval, it indicates that the deviation between the current reference battery capacity and the actual capacity is small. On the contrary, when delta is less than the minimum value of the preset interval, or greater than the maximum value of the preset interval, that is, when delta does not fall within the preset interval, it indicates that the deviation between the current reference battery capacity and the actual capacity is large, so it can be used as an abnormal state of the battery 10, and is recorded by adding one to the abnormal mark value N.

[0095] See also Figure 5 , judging whether to update the first corresponding relationship according to the abnormal mark value may specifically include the following steps.

[0096] Step S51, determining whether the abnormal flag value N is a second value.

[0097] If the judgment result is yes, execute step S52, otherwise execute step S53.

[0098] In some embodiments, the second value is greater than the first value, and the second value may be 5. Since the abnormal mark value N is increased by one when delta does not fall within the preset interval, that is, when the abnormal mark value N is the second value, it indicates that the state when delta does not fall within the preset interval has accumulated five cycles. At this time, since the deviation between the current reference battery capacity and the actual capacity is large and a large number of cycles have been accumulated, it is necessary to update the first corresponding relationship, so as to adapt to the abnormal state of the battery 10 to predict the life of the battery 10.

[0099] Step S52, obtaining a correction coefficient dn, and updating the first corresponding relationship according to the correction coefficient dn, and resetting the abnormal flag value N to the first value.

[0100] Wherein, updating the first corresponding relationship according to the correction coefficient dn may include updating the coefficient of the first-order term of the polynomial function in the first corresponding relationship to the correction coefficient dn. For example, updating d in formula (1) to the correction coefficient dn.

[0101] In some embodiments, the correction coefficient dn satisfies the following formula (3).

[0102] (3) Wherein, R is the reference battery capacity corresponding to the current cycle number according to the first corresponding relationship, a, b, c, e are the coefficients of the fourth term, the third term, the second term and the zero-order term of the polynomial function in the first corresponding relationship, respectively, and x is the current cycle number of the battery 10. Since the state where delta does not fall within the preset interval has accumulated five cycles, R here can be substituted into the current real capacity for calculation, so that the correction coefficient dn is associated with the current real capacity and the current cycle number of the battery 10, so that the correction coefficient dn can better reflect the real-time state of the battery 10, thereby improving the accuracy of the life prediction of the battery 10.

[0103] Step S53: Do not update the first corresponding relationship, and do not reset the abnormal flag value N to the first value.

[0104] Since step S53 is a subsequent step executed when the judgment result of step S51 is no, that is, at this time, the abnormal mark value N is greater than the first value and less than the second value, indicating that the deviation between the current reference battery capacity and the actual capacity is large and the cumulative number of cycles is still small. In order to reduce the accuracy of the life prediction method of the battery 10 caused by the acquisition error, when the deviation between the current reference battery capacity and the actual capacity is large and the cumulative number of cycles does not reach the second value, the first corresponding relationship is not updated, and the abnormal mark value N is not reset to the first value. In this way, if the deviation between the current reference battery capacity and the actual capacity is still large during the next charge and discharge cycle of the battery 10, according to the relevant description of step S46, the number of cycles corresponding to the large deviation between the current reference battery capacity and the actual capacity will be accumulated. When the cumulative number of cycles reaches the second value, it indicates that the probability that the actual capacity at this time is the acquisition error is small, and the probability that it is the actual acquisition value is large. Therefore, it is necessary to update the first corresponding relationship according to the correction coefficient dn, so as to improve the dynamic stability and accuracy of the life preset method of the battery 10.

[0105] The battery life prediction method provided by the present application is described below with reference to specific embodiments.

[0106] See also Figure 6 , Figure 6 Another flow chart of the battery life prediction method provided by the present application. In combination with a specific embodiment, the battery life prediction method may specifically include the following steps.

[0107] Step S61, obtaining the current cycle number n of the battery 10.

[0108] Step S62, determining whether the abnormal flag value N is a first value.

[0109] If the judgment result is yes, execute step S63, otherwise execute step S64.

[0110] Step S63, determining whether n is a multiple of a preset interval number.

[0111] If the judgment result is yes, execute step S64, otherwise execute step S613.

[0112] The detailed description of steps S61 to S63 can be found in Figure 3 The relevant description of step S31 will not be repeated here.

[0113] Step S64, obtaining a reference battery capacity corresponding to the current cycle number n according to the first corresponding relationship.

[0114] The specific description of step S64 can be found in Figure 3 The relevant description of step S32 will not be repeated here.

[0115] Step S65, obtaining the current real capacity of the battery 10.

[0116] Wherein, step S65 may be executed after step S64, or may be executed simultaneously with step S64, or may be executed before step S64. The present application does not impose any limitation on the execution order of step S64 and step S65.

[0117] Step S66, determining whether the difference delta between the reference battery capacity and the current actual capacity is greater than or equal to a minimum value of a preset interval, and less than or equal to a maximum value of a preset interval.

[0118] If the judgment result is yes, execute step S67, otherwise execute step S614.

[0119] The detailed description of steps S65 to S66 can be found in Figure 3 Step S33, Figure 4 The relevant description of step S41 will not be repeated here.

[0120] Step S67, determining whether delta is in the zero compensation interval.

[0121] If the judgment result is yes, execute step S68, otherwise execute step S69.

[0122] Step S68: Do not update the first corresponding relationship.

[0123] After executing step S68, step S610 is executed.

[0124] Step S69: updating the first corresponding relationship according to the compensation value corresponding to the non-zero compensation interval where delta is located.

[0125] Step S610, resetting the abnormal flag value N to a first value.

[0126] The detailed description of steps S67 to S610 can be found in Figure 4 The relevant descriptions of steps S42 to S45 are not repeated here.

[0127] Step S611, obtaining the derivative of the polynomial function of the updated or unupdated first correspondence.

[0128] Step S612 , taking the number of cycles corresponding to the derivative being greater than a preset threshold as the number of cycles at the end of life of the battery 10 .

[0129] The detailed description of step S611 to step S612 can be found in Figure 3 The relevant descriptions of steps S34 to S35 are not repeated here.

[0130] Step S613, controlling the battery 10 to enter the next charge and discharge cycle after normally completing the current charge and discharge cycle.

[0131] The specific description of step S613 can be found in Figure 3 The relevant description of step S36 will not be repeated here.

[0132] After executing step S613, return to execute step S61.

[0133] Step S614, increase the abnormal flag value N by one.

[0134] Step S6141, determine whether the abnormal mark value M is the second value.

[0135] If the judgment result is yes, execute step S6142, otherwise execute step S615.

[0136] Step S6142, obtain the correction coefficient dn, and update the first corresponding relationship according to the correction coefficient dn.

[0137] After executing step S6142, execute step S610.

[0138] Step S615: do not update the first corresponding relationship.

[0139] After executing step S615, step S611 is executed.

[0140] The specific description of steps S614 to S615 can be found in Figure 4 Step S46, Figure 5 The specific description of steps S51 to S53 will not be repeated here.

[0141] See also Figure 7 , Figure 7 This is a schematic diagram comparing the updated first corresponding relationship and the preset first corresponding relationship of the battery life prediction method provided by this application. Figure 7 As shown, the updated first correspondence is basically consistent with the first correspondence before the update, and through the battery life prediction method provided by the present application, after the preset first correspondence is updated, the first correspondence curve can be corrected according to different usage environments, thereby improving the accuracy of battery life prediction.

[0142] See also Figure 8 , Figure 8 This is a schematic diagram of the error of the first corresponding relationship after the battery life prediction method provided by this application is updated. Figure 8As shown, after 450 cycles, the error between the life end cycle number of the battery 10 predicted by the updated first correspondence and the first correspondence before the update is less than 2%, that is, the updated first correspondence has a higher accuracy.

[0143] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present application and are not intended to be limiting of the present application. As long as they are within the spirit and scope of the present application, appropriate changes and modifications to the above embodiments are within the scope of protection claimed in the present application.

Claims

1. A battery life prediction method, characterized in that: The method comprises: In an nth charge and discharge cycle of the battery, if a preset condition is met, determining a current reference battery capacity corresponding to n according to a preset first correspondence between the number of cycles n of the battery and the reference battery capacity, wherein n is a positive integer; Determining whether to update the first corresponding relationship according to a difference delta between the current reference battery capacity and the current actual capacity; If the first corresponding relationship is updated, the number of life end cycles of the battery is determined according to the updated first corresponding relationship; otherwise, the number of life end cycles of the battery is determined according to the first corresponding relationship that has not been updated.

2. The battery life prediction method according to claim 1, characterized in that: The satisfying of the preset conditions includes: The pre-stored abnormal flag value N is a first value and n is a multiple of a preset interval number; or, The abnormal flag value N is greater than the first value.

3. The battery life prediction method according to claim 1, characterized in that: The first corresponding relationship is a polynomial function of the cycle number n of the battery and the reference battery capacity, and updating the first corresponding relationship includes: The coefficients of the first-order terms of the polynomial function are updated.

4. The battery life prediction method according to claim 3, characterized in that: Determining whether to update the first corresponding relationship according to the difference delta between the current reference battery capacity and the current actual capacity includes: If delta is greater than or equal to the minimum value of the preset interval and less than or equal to the maximum value of the preset interval, determine whether to update the first corresponding relationship and whether to reset the abnormal mark value N to the first value based on the comparison result of delta and multiple preset interval endpoint values, wherein the multiple preset interval endpoint values ​​are all greater than or equal to the minimum value of the preset interval and less than or equal to the maximum value of the preset interval.

5. The battery life prediction method according to claim 4, characterized in that: The preset interval minimum value and the preset interval maximum value determine a preset interval, the multiple preset interval endpoint values ​​divide the preset interval into multiple preset sub-intervals, each of the preset sub-intervals corresponds to a compensation value, and the multiple preset sub-intervals include a zero compensation interval and a non-zero compensation interval. The determining whether to update the first corresponding relationship and to reset the abnormal flag value N to the first value according to the comparison result of delta and the multiple preset interval endpoint values ​​includes: Determine the preset sub-interval in which delta is located according to the comparison result between delta and the endpoint values ​​of the plurality of preset intervals; If delta is in the zero compensation interval, the first corresponding relationship is not updated, and the abnormal flag value N is reset to the first value; If delta is located in the non-zero compensation interval, the coefficient of the first-order term of the polynomial function is increased by the corresponding compensation value to update the first corresponding relationship, and the abnormal flag value N is reset to the first value.

6. The battery life prediction method according to claim 3, characterized in that: Determining whether to update the first corresponding relationship according to the difference delta between the current reference battery capacity and the current actual capacity includes: If delta is less than the minimum value of the preset interval, or greater than the maximum value of the preset interval, the abnormal mark value N is increased by one, and it is determined whether to update the first corresponding relationship according to the abnormal mark value.

7. The battery life prediction method according to claim 6, characterized in that: The determining whether to update the first corresponding relationship according to the abnormal flag value N includes: If the abnormal flag value N is a second value, obtaining a correction coefficient dn, and updating the coefficient of the first-order term of the polynomial function to the correction coefficient to update the first corresponding relationship, and resetting the abnormal flag value N to the first value, wherein the second value is greater than the first value; If the abnormal flag value N is greater than the first value and less than the second value, the first corresponding relationship is not updated, and the abnormal flag value N is not reset to the first value.

8. The battery life prediction method according to claim 7, characterized in that: The correction coefficient dn satisfies: Wherein, R is the current real capacity, a, b, c, e are respectively the coefficient of the fourth-order term, the coefficient of the third-order term, the coefficient of the second-order term and the coefficient of the zero-order term of the polynomial function, and x is the current number of cycles.

9. The battery life prediction method according to claim 1, characterized in that: The method further comprises: In the nth charge and discharge cycle of the battery, if n does not meet the preset condition, the battery is controlled to complete the nth charge and discharge cycle and enter the n+1th cycle.

10. The battery life prediction method according to claim 1, characterized in that: Determining the end-of-life cycle number of the battery includes: If the derivative of the polynomial function at at least one cycle number is greater than a preset threshold, the minimum value of the at least one cycle number is used as the end-of-life cycle number of the battery.

11. The battery life prediction method according to claim 1, characterized in that: In the nth charge and discharge cycle of the battery, if a preset condition is met, before determining the current reference battery capacity corresponding to n according to a preset first correspondence between the number of cycles of the battery and the reference battery capacity, the method further includes: In the process of charging and discharging batteries of the same type of the battery from zero cycle number to the battery capacity of the battery being less than or equal to the preset capacity, the battery capacities corresponding to a plurality of cycle numbers are collected and fitted to obtain the first corresponding relationship.

12. An electronic device, characterized in that: The electronic device comprises a battery management system, and the battery management system is used to execute the battery life prediction method according to any one of claims 1 to 11.

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