Method for predicting remaining discharge time of battery pack, battery pack, and storage medium

Abstract

The application discloses a battery pack residual discharge time prediction method, a battery pack and a computer readable storage medium. The method comprises the following steps: determining the current state of charge, the current discharge voltage and the current discharge current of the battery pack when the load device is discharged at a constant power; determining the discharge power of the battery pack according to the current discharge voltage and the current discharge current; determining the residual energy of the battery pack according to the rated charge capacity, the current discharge voltage and the current state of charge of the battery pack; and determining the residual discharge time of the battery pack according to the residual energy and the discharge power. The above method determines the residual energy of the battery pack, and determines the residual discharge time according to the residual energy and the discharge power, thereby solving the problem of low accuracy in calculating the residual discharge time of the battery pack according to the discharge current in the related art, and effectively improving the accuracy of predicting the residual discharge time of the battery pack.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of batteries, in particular to a method for predicting the remaining discharge time of a battery pack, a battery pack and a computer readable storage medium. BACKGROUND

[0002] When the battery pack discharges the load device, for current type load device, the remaining capacity of the battery pack is usually calculated according to the discharge current, and then the remaining discharge time of the battery pack is calculated according to the remaining capacity. For power type load device, constant power discharge is needed. Since the power needs to be kept constant during discharge, as the discharge voltage of the battery pack gradually decreases, the discharge current continues to rise. If the remaining discharge time of the battery pack is calculated according to the discharge current, the calculated remaining discharge time is too large, resulting in inaccurate predicted remaining discharge time.

[0003] Therefore, when discharging the power type load device, how to improve the accuracy of predicting the remaining discharge time of the battery pack becomes a problem to be solved. SUMMARY

[0004] The present application provides a method for predicting the remaining discharge time of a battery pack, a battery pack and a computer readable storage medium, by determining the remaining energy of the battery pack and determining the remaining discharge time according to the remaining energy and the discharge power, solving the problem of low accuracy in calculating the remaining discharge time of the battery pack according to the discharge current in the related art, and effectively improving the accuracy of predicting the remaining discharge time of the battery pack.

[0005] In a first aspect, the present application provides a method for predicting the remaining discharge time of a battery pack, the method comprising:

[0006] When discharging the load device at constant power, the current state of charge, the current discharge voltage and the current discharge current of the battery pack are determined; the discharge power of the battery pack is determined according to the current discharge voltage and the current discharge current; the remaining energy of the battery pack is determined according to the rated charge capacity, the current discharge voltage and the current state of charge of the battery pack; and the remaining discharge time of the battery pack is predicted according to the remaining energy and the discharge power.

[0007] In a second aspect, the present application also provides a battery pack, comprising a memory and a processor;

[0008] The memory is configured to store a computer program.

[0009] The processor is configured to implement the above-mentioned method for predicting the remaining discharge time of the battery pack when executing the computer program.

[0010] In a third aspect, the present application also provides a computer readable storage medium, characterized by storing a computer program, wherein the computer program is executed by a processor to implement the method for predicting the remaining discharge time of the battery pack.

[0011] The present application discloses a method for predicting the remaining discharge time of a battery pack, a battery pack and a computer readable storage medium, which determines the remaining energy of the battery pack, and determines the remaining discharge time according to the remaining energy and the discharge power, so as to calculate the remaining discharge time according to the remaining energy and the discharge power, and solve the problem of low accuracy in calculating the remaining discharge time of the battery pack according to the discharge current in the related art, and effectively improve the accuracy of predicting the remaining discharge time of the battery pack. BRIEF DESCRIPTION OF DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0013] Figure 1 is a structural schematic diagram of a battery pack provided by an embodiment of the present application;

[0014] Figure 2 is a schematic flow chart of a method for predicting the remaining discharge time of a battery pack provided by an embodiment of the present application;

[0015] Figure 3 is a schematic flow chart of a sub-step of determining the remaining energy provided by an embodiment of the present application;

[0016] Figure 4 is a schematic flow chart of a sub-step of determining the open circuit voltage set of the battery pack provided by an embodiment of the present application;

[0017] Figure 5 is a schematic flow chart of a sub-step of determining the state of charge set of the battery pack provided by an embodiment of the present application;

[0018] Figure 6 is a schematic flow chart of a sub-step of determining the remaining energy of the battery pack provided by an embodiment of the present application. DETAILED DESCRIPTION

[0019] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described, obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present application.

[0020] The flow chart shown in the drawings is only an example, and does not necessarily include all the contents and operations / steps, nor does it necessarily execute in the order described. For example, some operations / steps can be further decomposed, combined or partially merged, so the actual execution order may be changed according to the actual situation.

[0021] It should be understood that the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification and the appended claims of the present application, unless otherwise clear from the context, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0022] It should also be understood that the term "and / or" used in the specification and the appended claims of the present application means any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0023] The embodiments of the present application provide a battery pack remaining discharge time prediction method, a battery pack and a computer readable storage medium. The battery pack remaining discharge time prediction method is applied to the battery pack, the remaining discharge time is calculated according to the remaining energy and the discharge power by determining the remaining energy of the battery pack and determining the remaining discharge time according to the remaining energy and the discharge power, which solves the problem of low accuracy in calculating the remaining discharge time of the battery pack according to the discharge current in the related art, and effectively improves the accuracy of predicting the remaining discharge time of the battery pack.

[0024] For example, the battery pack can be a battery pack in an energy storage device, wherein the energy storage device can be an energy storage device on a vehicle, and can also be a portable energy storage device, which is not limited here.

[0025] For example, the energy storage device can detect and display the remaining discharge time of the battery pack.

[0026] Please refer to Figure 1 , Figure 1 is a structural schematic diagram of a battery pack 1000 provided by the embodiments of the present application. The battery pack 1000 can include a processor 1001 and a memory 1002, wherein the processor 1001 and the memory 1002 can be connected through a bus, such as an I 2C (Inter-integrated Circuit, integrated circuit) bus, or any applicable bus.

[0027] The memory 1002 can include a storage medium and an internal memory. The storage medium can store an operating system and a computer program. The computer program includes program instructions which, when executed, cause the processor to perform any of the methods for predicting the remaining discharge time of a battery pack.

[0028] The processor 1001 is configured to provide computing and control capabilities to support the operation of the entire battery pack 1000. Of course, the processor 1001 can be a main processor in the energy storage device or a processor in another battery pack in addition to being built into the battery pack 1000.

[0029] The processor 1001 can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0030] In one embodiment, the processor 1001 is configured to execute the computer program stored in the memory 1002 to implement the following steps:

[0031] When the load device is discharged at a constant power, the current state of charge, the current discharge voltage, and the current discharge current of the battery pack are determined. The discharge power of the battery pack is determined according to the current discharge voltage and the current discharge current. The remaining energy of the battery pack is determined according to the rated charge capacity, the current discharge voltage, and the current state of charge of the battery pack. The remaining discharge time of the battery pack is predicted according to the remaining energy and the discharge power.

[0032] In one embodiment, when the processor 1001 implements the step of determining the remaining energy of the battery pack according to the rated charge capacity, the current discharge voltage, and the current state of charge of the battery pack, the processor 1001 is configured to implement:

[0033] determining a discharge cut-off voltage of the battery pack; dividing the current discharge voltage and the discharge cut-off voltage to determine a discharge voltage set of the battery pack, the discharge voltage set including a plurality of discharge voltages; determining an open circuit voltage set of the battery pack according to the discharge voltage set and the discharge power, the open circuit voltage set including open circuit voltages corresponding to different discharge voltages of the battery pack; determining a state of charge set of the battery pack according to the open circuit voltage set based on a preset open circuit voltage and state of charge relationship table, the state of charge set including states of charge corresponding to the open circuit voltages in the open circuit voltage set; and determining a residual energy of the battery pack according to the discharge voltage set, the state of charge set, and a rated charge capacity.

[0034] In one embodiment, the processor 1001, when determining the open circuit voltage set of the battery pack according to the discharge voltage set and the discharge power, is configured to:

[0035] performing current calculation according to the discharge power and the discharge voltage set to obtain a discharge current set of the battery pack, the discharge current set including a plurality of discharge currents; determining an impedance set of the battery pack according to the discharge voltage set and the discharge current set, the impedance set including impedances corresponding to the discharge currents in the discharge current set; and performing open circuit voltage calculation according to the discharge voltage set, the discharge current set, and the impedance set based on an equivalent circuit model to obtain the open circuit voltage set of the battery pack.

[0036] In one embodiment, the processor 1001, when determining the impedance set of the battery pack according to the discharge voltage set and the discharge current set, is configured to:

[0037] determining a rated impedance value set according to the discharge voltage set, the rated impedance value set including rated impedance values of each discharge voltage in the discharge voltage set under a target discharge current; determining a cell temperature of the battery pack; and performing impedance calculation according to the cell temperature, the rated impedance value set, and the discharge current set to obtain the impedance set.

[0038] In one embodiment, the processor 1001, when determining the rated impedance value set according to the discharge voltage set, is configured to:

[0039] determining a target state of charge table corresponding to the target discharge current based on a preset correspondence between discharge currents and state of charge tables; calculating target states of charge corresponding to each discharge voltage in the discharge voltage set based on the target state of charge table; and generating the rated impedance value set according to rated impedance values corresponding to the target states of charge.

[0040] In one embodiment, the processor 1001, when performing the open circuit voltage calculation according to the discharge voltage set, the discharge current set, and the impedance set based on the equivalent circuit model to obtain the open circuit voltage set of the battery pack, is configured to:

[0041] The discharge current in each discharge current set is multiplied by the impedance corresponding to the same discharge current in the impedance set, to obtain an internal resistance voltage corresponding to each discharge current; and each open circuit voltage in the open circuit voltage set is determined according to the sum of the internal resistance voltage corresponding to each discharge current and the discharge voltage corresponding to the same discharge current in the discharge voltage set.

[0042] In one embodiment, the open circuit voltage and state of charge relationship table includes a plurality of open circuit voltages corresponding to a plurality of states of charge; and when the processor 1001 determines the state of charge set of the battery pack according to the open circuit voltage set based on the preset open circuit voltage and state of charge relationship table, the processor 1001 is configured to:

[0043] determine an open circuit voltage interval to which each open circuit voltage in the open circuit voltage set belongs, the open circuit voltage interval including a first open circuit voltage and a second open circuit voltage; determine a state of charge interval corresponding to each open circuit voltage according to the open circuit voltage interval to which the open circuit voltage belongs, the state of charge interval including a first state of charge corresponding to the first open circuit voltage and a second state of charge corresponding to the second open circuit voltage; and calculate the state of charge corresponding to each open circuit voltage according to the open circuit voltage interval and the state of charge interval corresponding to the open circuit voltage.

[0044] In one embodiment, when the processor 1001 determines the remaining energy of the battery pack according to the discharge voltage set, the state of charge set and the rated charge capacity, the processor 1001 is configured to:

[0045] average two adjacent discharge voltages in the discharge voltage set to obtain a plurality of average voltage values arranged in sequence; subtract two adjacent states of charge in the state of charge set to obtain a plurality of state of charge difference values arranged in sequence; multiply each average voltage value arranged in sequence by the state of charge difference value corresponding to the same sequence, and multiply the sum of the products by the rated charge capacity to obtain the remaining energy.

[0046] Some embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the case of no conflict, the embodiments described below and the features in the embodiments can be combined with each other. Please refer to Figure 2 , Figure 2 is a schematic flowchart of a battery pack remaining discharge time prediction method provided by an embodiment of the present application. As shown in Figure 2 , the battery pack remaining discharge time prediction method includes steps S10 to S40.

[0047] In step S10, when the load device is discharged at a constant power, the current state of charge, the current discharge voltage and the current discharge current of the battery pack are determined.

[0048] It should be noted that the method for predicting the remaining discharge time of the battery pack in the embodiments of the present application can be applied to the scenario of constant power discharge of the battery pack to the load device. By determining the remaining energy of the battery pack and determining the remaining discharge time according to the remaining energy and the discharge power, the problem of low accuracy in calculating the remaining discharge time of the battery pack according to the discharge current in the related art is solved, and the accuracy of predicting the remaining discharge time of the battery pack can be effectively improved.

[0049] For example, the load device refers to an external power consumption device. For example, relative to the energy storage device, the load device can be various household appliances, and can also be various electronic devices or electronic instruments on a vehicle, and the like.

[0050] In some embodiments, when the load device is discharged at a constant power, the current state of charge, the current discharge voltage, and the current discharge current of the battery pack are determined.

[0051] It should be noted that constant power discharge refers to keeping the power unchanged during the discharge process, and as the discharge voltage decreases, the discharge current increases. The state of charge (SOC) refers to the percentage of the remaining capacity of the battery pack to the battery capacity in the fully charged state.

[0052] For example, when the load device is discharged at a constant power, the current state of charge, the current discharge voltage, and the current discharge current of the battery pack can be detected by the battery management system (BMS).

[0053] In the embodiments of the present application, the current state of charge, the current discharge voltage, and the current discharge current of the battery pack at any time during the constant power discharge of the load device can be obtained. For example, the current state of charge, the current discharge voltage, and the current discharge current of the battery pack at T0 time when the constant power discharge of the load device starts can be obtained. For another example, the current state of charge, the current discharge voltage, and the current discharge current of the battery pack at T1 time when the constant power discharge of the load device is performed can be obtained. For ease of description, the current state of charge can be denoted as SOC0, the current discharge voltage can be denoted as U0, and the current discharge current can be denoted as I0.

[0054] In step S20, the discharge power of the battery pack is determined according to the current discharge voltage and the current discharge current.

[0055] In the embodiments of the present application, after the current state of charge, the current discharge voltage, and the current discharge current of the battery pack are determined, the discharge power of the battery pack can be determined according to the current discharge voltage and the current discharge current.

[0056] For example, the discharge power of the battery pack can be calculated by multiplying the current discharge voltage and the current discharge current. For example, for the current discharge voltage U0, the current discharge current I0, the discharge power P of the battery pack is calculated as P = U0 x I0.

[0057] By determining the discharge power of the battery pack according to the current discharge voltage and the current discharge current, the remaining discharge time of the battery pack can be predicted according to the discharge power and the remaining energy of the battery pack.

[0058] In step S30, the remaining energy of the battery pack is determined according to the rated charge capacity of the battery pack, the current discharge voltage, and the current state of charge.

[0059] For example, the remaining energy (State of Energy, SOE) of the battery pack can be calculated according to the rated charge capacity Q0 of the battery pack, the current discharge voltage U0, and the current state of charge SOC0. The rated charge capacity of the battery pack recorded by the BMS system can be read. It should be noted that the rated charge capacity Q0 refers to the capacity that the battery pack can reach after design.

[0060] In step S40, the remaining discharge time of the battery pack is predicted according to the remaining energy and the discharge power.

[0061] In some embodiments, after determining the remaining energy of the battery pack, the remaining discharge time of the battery pack can be calculated according to the remaining energy and the discharge power.

[0062] For example, for the remaining energy SOE and the discharge power P, the remaining discharge time t of the battery pack can be calculated as t = SOE / P.

[0063] In the above embodiments, by determining the remaining energy of the battery pack and determining the remaining discharge time according to the remaining energy and the discharge power, the remaining discharge time can be calculated according to the remaining energy and the discharge power, which solves the problem of low accuracy in calculating the remaining discharge time of the battery pack according to the discharge current in the related art, and effectively improves the accuracy of predicting the remaining discharge time of the battery pack.

[0064] In the embodiments of the present application, how to determine the remaining energy will be described in detail. Please refer to Figure 3 , Figure 3 is a schematic flowchart of a sub-step of determining the remaining energy provided by the embodiments of the present application. The determination of the remaining energy in step S30 can include the following steps S301 to S305.

[0065] In step S301, the discharge cutoff voltage of the battery pack is determined.

[0066] It should be noted that the discharge cut-off voltage refers to the minimum working voltage value at which the battery pack is not suitable for further discharging when the battery pack is discharging. The termination voltage is different for different battery types and different discharge conditions. The discharge cut-off voltage can be represented as U_end.

[0067] For example, the discharge cut-off voltage of the battery pack recorded by the BMS system can be read. For example, when the state of charge of the battery pack is 100%, the corresponding discharge voltage can be 4000mV; when the state of charge of the battery pack is 0%, the corresponding discharge voltage can be 3000mV, that is, the discharge cut-off voltage U_end of the battery pack is 3000mV.

[0068] In step S302, the discharge voltage set of the battery pack is determined according to voltage division of the current discharge voltage and the discharge cut-off voltage. The discharge voltage set includes a plurality of discharge voltages.

[0069] In the embodiments of the present application, after the discharge cut-off voltage of the battery pack is determined, the discharge voltage set of the battery pack can be determined according to voltage division of the current discharge voltage and the discharge cut-off voltage.

[0070] For example, for the discharge cut-off voltage U_end and the current discharge voltage U0, if the current discharge voltage U0 is 4000mV and the discharge cut-off voltage U_end is 3000mV, voltage division can be performed between 4000mV and 3000mV to obtain a discharge voltage set including a plurality of discharge voltages. The division point of voltage division can be set according to actual conditions, and the specific value is not limited herein. For example, every 200mV can be taken as a division point, or every 100mV can be taken as a division point, etc.

[0071] For example, when the division point is 200mV, voltage division can be performed on 4000mV and 3000mV, and the corresponding discharge voltage set is {U0=4000mV, U1=3800mV, U2=3600mV, U3=3400mV, U4=3200mV, U5=3000mV}.

[0072] The above embodiments determine the discharge voltage set of the battery pack according to voltage division of the current discharge voltage and the discharge cut-off voltage. Subsequently, the open circuit voltage of the battery pack under different discharge voltages can be determined according to the discharge voltage set, and then the state of charge of the battery pack under different open circuit voltages can be determined.

[0073] In step S303, the open circuit voltage set of the battery pack is determined according to the discharge voltage set and the discharge power. The open circuit voltage set includes the open circuit voltage corresponding to the battery pack under different discharge voltages.

[0074] In the embodiment of the present application, after the discharge voltage set of the battery pack is determined, the open circuit voltage set of the battery pack can be determined according to the discharge voltage set and the discharge power. The open circuit voltage set includes the open circuit voltage corresponding to each discharge voltage of the battery pack.

[0075] For example, the open circuit voltage corresponding to each discharge voltage in the discharge voltage set can be determined respectively. The discharge power is used to determine the discharge current corresponding to each discharge voltage in the discharge voltage set, and then the open circuit voltage can be determined according to the discharge voltage and the discharge current based on the equivalent circuit model. Details of how to determine the open circuit voltage will be described below.

[0076] By determining the open circuit voltage set of the battery pack according to the discharge voltage set and the discharge power, the open circuit voltage corresponding to each discharge voltage of the battery pack can be obtained.

[0077] Please refer to Figure 4 , Figure 4 is a schematic flowchart of a sub-step of determining the open circuit voltage set of the battery pack provided in the embodiment of the present application. The step S303 of determining the open circuit voltage set of the battery pack can include the following steps S3031 to S3033.

[0078] In step S3031, current calculation is performed according to the discharge power and the discharge voltage set to obtain the discharge current set of the battery pack. The discharge current set includes a plurality of discharge currents.

[0079] In some embodiments, the discharge current set of the battery pack can be obtained by performing current calculation according to the discharge power and the discharge voltage set.

[0080] For example, for the discharge power P and the discharge voltage set {U0, U1, U2, U3, U4, U5}, the discharge current set of the battery pack can be calculated according to the current calculation formula I=P / U, for example, the discharge current set is {I0, I1, I2, I3, I4, I5}.

[0081] In step S3032, the impedance set of the battery pack is determined according to the discharge voltage set and the discharge current set. The impedance set includes the impedance corresponding to each discharge current in the discharge current set.

[0082] It should be noted that in the embodiment of the present application, the impedance of the battery pack is not a fixed value, but changes with the change of the discharge voltage and the discharge current, so the impedance of the battery pack needs to be determined according to the discharge voltage and the discharge current.

[0083] Exemplarily, the impedance set of the battery pack can be determined according to the discharge voltage set {U0, U1, U2, U3, U4, U5} and the discharge current set {I0, I1, I2, I3, I4, I5}. For example, the impedance set can be represented as {R0, R1, R2, R3, R4, R5}.

[0084] In the above embodiment, by determining the impedance set of the battery pack according to the discharge voltage set and the discharge current set, the impedance corresponding to each discharge current in the discharge current set can be obtained, and then the influence of the discharge current on the impedance can be introduced in the calculation of the remaining discharge time, thereby solving the problem that the influence of the discharge current on the impedance is ignored in the calculation of the remaining discharge time in the related art, and the accuracy of predicting the remaining discharge time of the battery pack can be effectively improved.

[0085] In the embodiments of the present application, how to determine the impedance set will be described in detail.

[0086] In some embodiments, determining the impedance set of the battery pack according to the discharge voltage set and the discharge current set can include: determining a rated resistance value set according to the discharge voltage set, the rated resistance value set including a rated resistance value of each discharge voltage in the discharge voltage set under a target discharge current; determining a temperature of the battery cell of the battery pack; and performing impedance calculation according to the temperature of the battery cell, the rated resistance value set and the discharge current set to obtain the impedance set.

[0087] Exemplarily, the impedance R can be calculated by the following impedance formula:

[0088] R = r * exp(A * I + BT)

[0089] In the formula, r is the rated resistance value of each discharge voltage under the target discharge current; A and B represent coefficients, T represents the temperature of the battery cell, and I represents the discharge current. The coefficients A and B can be set according to actual conditions, and the specific values are not limited herein. The target discharge current can be set according to actual conditions, and the specific value is not limited herein. For example, the target discharge current can be 0.1C.

[0090] In the above embodiment, by determining the rated resistance value set according to the discharge voltage set and performing impedance calculation according to the temperature of the battery cell, the rated resistance value set and the discharge current set, the factor that the rated resistance values of different discharge voltages under the target discharge current are different and can cause the impedance corresponding to the discharge current to change can be fully considered, the accuracy of determining the impedance of the battery pack can be improved, and the accuracy of predicting the remaining discharge time of the battery pack is further improved.

[0091] In some embodiments, when the set of rated resistances is determined according to the set of discharge voltages, the following operations can be included: determining a target state of charge table corresponding to a target discharge current based on a preset correspondence between the discharge current and the state of charge table; calculating a target state of charge corresponding to each discharge voltage in the set of discharge voltages based on the target state of charge table; and generating the set of rated resistances according to the rated resistance corresponding to each target state of charge.

[0092] It should be noted that different discharge currents correspond to different state of charge tables. The state of charge table can include a state of charge, a discharge voltage corresponding to the state of charge, and a rated resistance corresponding to the state of charge, and the like. In the embodiments of the present application, the discharge current and the corresponding state of charge table can be pre-stored in association. For example, when the discharge current is 0.1C, a state of charge table is corresponded, which is denoted as state of charge table 1.

[0093] For example, the target state of charge table corresponding to the target discharge current can be determined based on a preset correspondence between the discharge current and the state of charge table. For example, when the target discharge current is 0.1C, the target state of charge table can be determined as the state of charge table 1. Then, the target state of charge corresponding to each discharge voltage in the set of discharge voltages is calculated based on the state of charge table 1. For example, the target state of charge corresponding to each discharge voltage in the set of discharge voltages {U0, U1, U2, U3, U4, U5} can be calculated based on an interpolation calculation formula, and the target state of charge can be expressed as SOC goal_0 , SOC goal_1 , SOC goal_2 , SOC goal_3 , SOC goal_4 , SOC goal_5 . Finally, the set of rated resistances is generated according to the rated resistance corresponding to each target state of charge. For example, the set of rated resistances can be expressed as {r0, r1, r2, r3, r4, r5}.

[0094] In the embodiments of the present application, the temperature of the battery cell of the battery pack can be detected by a temperature sensor. Then, the impedance set is obtained by performing impedance calculation according to the cell temperature, the set of rated resistances, and the set of discharge currents.

[0095] For example, for the cell temperature T, the set of rated resistances {r0, r1, r2, r3, r4, r5}, and the set of discharge currents {I0, I1, I2, I3, I4, I5}, the impedance set {R0, R1, R2, R3, R4, R5} can be calculated by using the above impedance formula.

[0096] For example, when the rated resistance is r0, the cell temperature T, the rated resistance r0, and the discharge current I0 can be substituted into the impedance formula to obtain the impedance R0=r0*exp(A*I0+BT). For another example, when the rated resistance is r1, the cell temperature T, the rated resistance r1, and the discharge current I1 can be substituted into the impedance formula to obtain the impedance R1=r1*exp(A*I1+BT). Similarly, the impedance set is calculated. The specific calculation process is not described here.

[0097] In the above embodiment, by determining the target state of charge corresponding to the target discharge current, calculating the target state of charge corresponding to each discharge voltage based on the target state of charge table, and generating the rated resistance set according to the rated resistance corresponding to each target state of charge, the rated resistance of the battery pack under different discharge voltages and target discharge currents can be determined.

[0098] In step S3033, based on the equivalent circuit model, the open circuit voltage set of the battery pack is obtained by calculating the open circuit voltage based on the discharge voltage set, the discharge current set, and the impedance set.

[0099] In the embodiment of the present application, after obtaining the discharge current set and the impedance set, the open circuit voltage set of the battery pack can be obtained by calculating the open circuit voltage based on the equivalent circuit model, the discharge voltage set, the discharge current set, and the impedance set.

[0100] For example, the equivalent circuit model can include but is not limited to Rint equivalent circuit model, Thevenin equivalent circuit model, or PNGV equivalent circuit model, etc. In the embodiment of the present application, the Rint equivalent circuit model is taken as an example to illustrate how to calculate the open circuit voltage.

[0101] In some embodiments, based on the equivalent circuit model, the open circuit voltage set of the battery pack can be obtained by calculating the open circuit voltage based on the discharge voltage set, the discharge current set, and the impedance set, which can include: multiplying each discharge current in the discharge current set and the impedance corresponding to the same discharge current in the impedance set to obtain the internal resistance voltage corresponding to each discharge current; and determining each open circuit voltage in the open circuit voltage set according to the sum of the internal resistance voltage corresponding to each discharge current and the discharge voltage corresponding to the same discharge current in the discharge voltage set.

[0102] It should be noted that in the Rint equivalent circuit model, the discharge voltage U=OCV-IR, i.e. OCV=U+IR. Wherein, OCV represents the open circuit voltage, and IR represents the internal resistance voltage.

[0103] For example, for the discharge current set {I0, I1, I2, I3, I4, I5} and the impedance set {R0, R1, R2, R3, R4, R5}, the discharge current I0 can be multiplied by the impedance R0 to obtain the internal resistance voltage corresponding to the discharge current I0, the discharge current I1 can be multiplied by the impedance R1 to obtain the internal resistance voltage corresponding to the discharge current I1, and so on, so that the internal resistance voltage corresponding to each discharge current can be obtained.

[0104] For example, for the discharge current I0, the corresponding internal resistance voltage is I0R0, and the corresponding discharge voltage is U0, the open circuit voltage OCV0 can be determined as OCV0=U0+I0R0; for the discharge current I1, the corresponding internal resistance voltage is I1R1, and the corresponding discharge voltage is U1, the open circuit voltage OCV1 can be determined as OCV1=U1+I1R1; and so on, so that each open circuit voltage in the open circuit voltage set {OCV0, OCV1, OCV2, OCV3, OCV4, OCV5} can be determined.

[0105] The above embodiment determines the internal resistance voltage corresponding to each discharge current, and determines each open circuit voltage in the open circuit voltage set according to the sum of the corresponding internal resistance voltage and the discharge voltage corresponding to the same discharge current in the discharge voltage set, so that the accuracy of calculating the open circuit voltage can be effectively improved by considering the influence of the internal resistance voltage on the open circuit voltage.

[0106] In step S304, the state of charge set of the battery pack is determined according to the open circuit voltage set based on the preset open circuit voltage and state of charge relationship table, and the state of charge set includes the state of charge corresponding to each open circuit voltage in the open circuit voltage set.

[0107] In the embodiment of the present application, after the open circuit voltage set of the battery pack is determined, the state of charge set of the battery pack can be determined according to the open circuit voltage set based on the preset open circuit voltage and state of charge relationship table.

[0108] For example, the state of charge set can be represented as {SOC0, SOC1, …, SOC n Please refer to Table 1, which is an open circuit voltage and state of charge relationship table provided by the embodiment of the present application.

[0109] Table 1

[0110]

[0111] Referring to Figure 5 , Figure 5 is a schematic flowchart of a sub-step of determining a set of state of charge of a battery pack, the step S304 of determining a set of state of charge of a battery pack can include the following steps S3041-S3043.

[0112] Step S3041, determining an open-circuit voltage interval to which each open-circuit voltage in the set of open-circuit voltages belongs, the open-circuit voltage interval including a first open-circuit voltage and a second open-circuit voltage.

[0113] For example, in combination with Table 1, an open-circuit voltage interval to which each open-circuit voltage in the set of open-circuit voltages {OCV0, OCV1, OCV2, OCV3, OCV4, OCV5} belongs can be determined, wherein the open-circuit voltage interval includes a first open-circuit voltage and a second open-circuit voltage.

[0114] For example, for the open-circuit voltage OCV1, if the open-circuit voltage OCV1=4100mV, it can be determined that the open-circuit voltage OCV1 belongs to the open-circuit voltage interval (4152mV, 4051mV), wherein the first open-circuit voltage is 4152mV and the second open-circuit voltage is 4051mV. For another example, for the open-circuit voltage OCV2, if the open-circuit voltage OCV2=3900mV, it can be determined that the open-circuit voltage OCV2 belongs to the open-circuit voltage interval (3957mV, 3870mV), wherein the first open-circuit voltage is 3957mV and the second open-circuit voltage is 3870mV.

[0115] Step S3042, determining a state of charge interval corresponding to each open-circuit voltage according to the open-circuit voltage interval to which each open-circuit voltage belongs, the state of charge interval including a first state of charge corresponding to the first open-circuit voltage and a second state of charge corresponding to the second open-circuit voltage.

[0116] For example, after determining the open-circuit voltage interval to which each open-circuit voltage in the set of open-circuit voltages belongs, a state of charge interval corresponding to each open-circuit voltage can be determined according to the open-circuit voltage interval to which each open-circuit voltage belongs based on a preset open-circuit voltage and state of charge relationship table.

[0117] For example, based on the corresponding relationship between the open-circuit voltage and the state of charge in Table 1, if the open-circuit voltage interval corresponding to the open-circuit voltage OCV1 is (4152mV, 4051mV), it can be determined that the state of charge interval corresponding to the open-circuit voltage OCV1 is (80%, 70%), wherein the first open-circuit voltage 4152mV corresponds to the state of charge 80% and the second open-circuit voltage 4051mV corresponds to the state of charge 70%.

[0118] For example, if the open-circuit voltage interval corresponding to the open-circuit voltage OCV2 is (3957 mV, 3870 mV), it can be determined that the state of charge interval corresponding to the open-circuit voltage OCV2 is (60%, 50%), wherein the first open-circuit voltage 3957 mV corresponds to the state of charge 60%, and the second open-circuit voltage 3870 mV corresponds to the state of charge 50%.

[0119] In step S3043, the state of charge corresponding to each open-circuit voltage is calculated according to the open-circuit voltage interval and the state of charge interval corresponding to each open-circuit voltage.

[0120] For example, the state of charge corresponding to each open-circuit voltage can be calculated according to the open-circuit voltage interval and the state of charge interval corresponding to each open-circuit voltage based on an interpolation calculation formula.

[0121] The interpolation calculation formula is as follows:

[0122] SOC = k * OCV + b

[0123] In the formula, k and b denote parameters.

[0124] For example, for the open-circuit voltage OCV1, the open-circuit voltage interval (4152 mV, 4051 mV) and the state of charge interval (80%, 70%) corresponding to the open-circuit voltage OCV1 are substituted into the above interpolation calculation formula to calculate the values of the parameters k and b . Then, the open-circuit voltage OCV1=4100 mV is substituted into the above interpolation calculation formula to calculate the state of charge, and it can be determined that the state of charge SOC1 corresponding to the open-circuit voltage OCV1 is 74.8%. Similarly, the state of charge corresponding to each open-circuit voltage can be calculated. The specific calculation process is not described herein.

[0125] In the above embodiment, the state of charge corresponding to each open-circuit voltage can be conveniently and accurately calculated based on the interpolation calculation formula, and the accuracy of determining the state of charge of the battery pack is improved.

[0126] In step S305, the residual energy of the battery pack is determined according to the set of discharge voltages, the set of states of charge, and the rated charge capacity.

[0127] In the embodiments of the present application, after the set of states of charge of the battery pack is determined according to the set of open-circuit voltages, the residual energy of the battery pack can be determined according to the set of discharge voltages, the set of states of charge, and the rated charge capacity.

[0128] Please refer to Figure 6 , Figure 6is a schematic flowchart of a sub-step of determining the residual energy of the battery pack provided by the embodiment of the present application. The step S305 of determining the residual energy of the battery pack can include the following steps S3051 to S3053.

[0129] In step S3051, the average of two adjacent discharge voltages in the discharge voltage set is obtained, and a plurality of average voltage values arranged in sequence are obtained.

[0130] For example, the average of two adjacent discharge voltages in the discharge voltage set {U0, U1, U2, U3, U4, U5} can be obtained, and a plurality of average voltage values U0= (U0+U1) / 2, U1= (U1+U2) / 2, U2= (U2+U3) / 2, U3= (U3+U4) / 2, U4= (U4+U5) / 2 are obtained. n_avg i i+1 0_avg 1_avg 4_avg For example, the average of two adjacent discharge voltages in the discharge voltage set {U0, U1, U2, U3, U4, U5} can be obtained, and a plurality of average voltage values U0= (U0+U1) / 2, U1= (U1+U2) / 2, U2= (U2+U3) / 2, U3= (U3+U4) / 2, U4= (U4+U5) / 2 are obtained.

[0131] It should be noted that by taking the average of two adjacent discharge voltages in the discharge voltage set, the change of the discharge voltage can be more gentle, the fluctuation can be reduced, and the accuracy of calculating the residual energy can be improved.

[0132] In step S3052, the difference between two adjacent state of charges in the state of charge set is obtained, and a plurality of state of charge difference values arranged in sequence are obtained.

[0133] For example, for the state of charge set {SOC0, SOC1, SOC2, SOC3, SOC4, SOC5}, the difference between two adjacent state of charges in the state of charge set {SOC0, SOC1, SOC2, SOC3, SOC4, SOC5} can be obtained, and a plurality of state of charge difference values are obtained, for example, ΔSOC_0=SOC0–SOC1,... ΔSOC_n= SOCn–SOCn-1, wherein n represents the sequence number of the state of charge.

[0134] In step S3053, the plurality of average voltage values arranged in sequence are multiplied by the state of charge difference values corresponding to the same sequence respectively, and the sum of the products is multiplied by the rated charge capacity to obtain the residual energy.

[0135] For example, after obtaining the plurality of average voltage values arranged in sequence and the plurality of state of charge difference values arranged in sequence, the plurality of average voltage values arranged in sequence can be multiplied by the state of charge difference values corresponding to the same sequence respectively, and the sum of the products is multiplied by the rated charge capacity to obtain the residual energy.​​​​​

[0136] For example, the residual energy is calculated by the following formula:

[0137] Residual energy SOE = (U 0_avg *ΔSOC_0+...+U n_avg *ΔSOC_n) * Q0

[0138] The specific calculation process is not described here.

[0139] The above embodiment can calculate the residual energy by multiplying the plurality of average voltage values arranged in sequence with the state of charge difference corresponding to the same sequence respectively, and multiplying the sum of the products with the rated charge capacity.

[0140] The embodiment of the application also provides a computer readable storage medium, which stores a computer program, and the computer program includes program instructions. The processor executes the program instructions to realize any one of the prediction methods of the residual discharge time of the battery pack provided by the embodiments of the application.

[0141] For example, the program is loaded by the processor, and the following steps can be executed:

[0142] When the load device is discharged at a constant power, the current state of charge, the current discharge voltage and the current discharge current of the battery pack are determined. The discharge power of the battery pack is determined according to the current discharge voltage and the current discharge current. The residual energy of the battery pack is determined according to the rated charge capacity, the current discharge voltage and the current state of charge of the battery pack. The residual discharge time of the battery pack is predicted according to the residual energy and the discharge power.

[0143] The computer readable storage medium can be an internal storage unit of the battery pack of the foregoing embodiments, such as a hard disk or a memory of the battery pack. The computer readable storage medium can also be an external storage device of the battery pack, such as a plug-in hard disk, a smart media card (SMC), a secure digital card (SD card), a flash card and the like.

[0144] Further, the computer readable storage medium can mainly include a storage program area and a storage data area. The storage program area can store an operating system, programs required by at least one function and the like. The storage data area can store data created according to each program and the like.

[0145] The above merely provides the specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present application, and these modifications or replacements should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for predicting the remaining discharge time of a battery pack, characterized in that, The method is applied to a battery pack, and the method comprises: When discharging the load device at a constant power, determining a current state of charge, a current discharge voltage and a current discharge current of the battery pack; According to the current discharge voltage and the current discharge current, determining a discharge power of the battery pack; According to the rated charge capacity, the current discharge voltage and the current state of charge of the battery pack, determining a residual energy of the battery pack; According to the residual energy and the discharge power, predicting a residual discharge time of the battery pack; The method further comprises: determining a discharge cut-off voltage of the battery pack; dividing the current discharge voltage and the discharge cut-off voltage to determine a discharge voltage set of the battery pack, the discharge voltage set comprising a plurality of discharge voltages; according to the discharge voltage set and the discharge power, determining an open circuit voltage set of the battery pack, the open circuit voltage set comprising open circuit voltages corresponding to different discharge voltages of the battery pack; according to a preset open circuit voltage and state of charge relationship table, determining a state of charge set of the battery pack according to the open circuit voltage set, the state of charge set comprising a state of charge corresponding to each open circuit voltage in the open circuit voltage set; and according to the discharge voltage set, the state of charge set and the rated charge capacity, determining the residual energy of the battery pack.

2. The method of claim 1, wherein, The method further comprises: According to the discharge power and the discharge voltage set, performing current calculation to obtain a discharge current set of the battery pack, the discharge current set comprising a plurality of discharge currents; according to the discharge voltage set and the discharge current set, determining an impedance set of the battery pack, the impedance set comprising an impedance corresponding to each discharge current in the discharge current set; and according to the discharge voltage set, the discharge current set and the impedance set, performing open circuit voltage calculation based on an equivalent circuit model to obtain the open circuit voltage set of the battery pack. The method further comprises: According to the discharge voltage set, determining a rated impedance value set, the rated impedance value set comprising a rated impedance value of each discharge voltage in the discharge voltage set under a target discharge current; determining a cell temperature of the battery pack; and according to the cell temperature, the rated impedance value set and the discharge current set, performing impedance calculation to obtain the impedance set.

3. The method of claim 2, wherein, The method further comprises: According to a preset correspondence between a discharge current and a state of charge table, determining a target state of charge table corresponding to the target discharge current; according to the target state of charge table, calculating a target state of charge corresponding to each discharge voltage in the discharge voltage set; and according to a rated impedance value corresponding to each target state of charge, generating the rated impedance value set. ​ ​ 4. The method of claim 3, wherein, ​ ​ ​ ​ 5. The method of claim 2, wherein, The open-circuit voltage set of the battery pack is obtained by calculating the open-circuit voltage based on the discharge voltage set, the discharge current set and the impedance set, comprising: Multiplying each discharge current in the discharge current set by the impedance corresponding to the same discharge current in the impedance set to obtain the internal resistance voltage corresponding to each discharge current. Each open-circuit voltage in the open-circuit voltage set is determined according to the sum of the internal resistance voltage corresponding to each discharge current and the discharge voltage corresponding to the same discharge current in the discharge voltage set. 6.The method of claim 1, wherein, The open-circuit voltage and state of charge relationship table includes open-circuit voltages corresponding to a plurality of states of charge; The state of charge set of the battery pack is determined according to the open-circuit voltage set based on the preset open-circuit voltage and state of charge relationship table, comprising: Each open-circuit voltage interval to which each open-circuit voltage in the open-circuit voltage set belongs is determined, and the open-circuit voltage interval includes a first open-circuit voltage and a second open-circuit voltage; The state of charge interval corresponding to each open-circuit voltage is determined according to the open-circuit voltage interval to which each open-circuit voltage belongs, and the state of charge interval includes a first state of charge corresponding to the first open-circuit voltage and a second state of charge corresponding to the second open-circuit voltage; The state of charge corresponding to each open-circuit voltage is calculated according to the open-circuit voltage interval and the state of charge interval corresponding to each open-circuit voltage.

7. The method of claim 1, wherein, The remaining energy of the battery pack is determined according to the discharge voltage set, the state of charge set and the rated charge capacity, comprising: The average voltage values in a plurality of sequences are obtained by averaging adjacent two discharge voltages in the discharge voltage set; The state of charge difference values in a plurality of sequences are obtained by subtracting adjacent two states of charge in the state of charge set; The product of each average voltage value in a plurality of sequences and the state of charge difference value corresponding to the same sequence is obtained, and the sum of the products is multiplied by the rated charge capacity to obtain the remaining energy.

8. A battery pack, characterized by, The battery pack includes a memory and a processor; The memory is used to store a computer program; The processor is used to implement the prediction method of the remaining discharge time of the battery pack according to any one of claims 1 to 7 when the computer program is executed.

9. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, and the computer program is executed by the processor to implement the prediction method of the remaining discharge time of the battery pack according to any one of claims 1 to 7. The computer readable storage medium stores a computer program, and the computer program is executed by the processor to implement the prediction method of the remaining discharge time of the battery pack according to any one of claims 1 to 7.

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