Method for determining battery impedance, electronic device and computer readable storage medium

Abstract

The present application is about a method, an electronic device and a computer-readable storage medium for determining battery impedance. According to one embodiment, the method for determining battery impedance includes: obtaining a first voltage Vn, a first current In and a first temperature Tn of the battery at a time point Dn, where n=0, 1, 2, 3..., and n is a non-negative integer; determining a first depth of discharge DODn of the battery at a time point Dn based on the first voltage Vn, the first current In and the first temperature Tn; determining a first impedance Rn based on the first depth of discharge DODn determined at the time point Dn. The method, electronic device and computer-readable storage medium for determining battery impedance provided by the embodiments of the present application can realize a more accurate update of the battery impedance, and thus can accurately predict the remaining power of the battery.

Description

Technical Field

[0001] Embodiments of the present application relate to the field of batteries, and in particular, to a method for determining battery impedance, an electronic device, and a computer-readable storage medium. Background Art

[0002] At present, lithium-ion batteries have the advantages of high energy density, high power density, many cycles and long storage time. They have broad application prospects in large and medium-sized electric equipment such as electric vehicles and energy storage facilities. Therefore, lithium-ion batteries have become the key to solving global problems such as energy crisis and environmental pollution.

[0003] During the use of lithium-ion batteries, as time goes by, lithium-ion batteries will gradually age, which will cause the impedance of lithium-ion batteries to increase significantly. If the impedance of the lithium-ion battery cannot be updated in time, the accuracy of the power algorithm cannot be guaranteed, which will cause the remaining capacity of the lithium-ion battery to be displayed inaccurately, thus affecting the user's use. For example, if the remaining capacity of the battery cannot be accurately predicted, the electric vehicle may lose kinetic energy while driving on the highway, resulting in danger or accidents. For example, if the remaining capacity of the battery cannot be accurately predicted, it may not be possible to make a correct judgment on whether to charge the vehicle battery. If the electric vehicle loses kinetic energy at a relatively far distance from the charging station (for example, in a desert or wilderness), it will cause great inconvenience and even affect safety (lack of battery to provide heat energy in a low temperature environment).

[0004] Therefore, there are still many technical problems to be solved in the industry regarding how to update the battery impedance in a timely and accurate manner. Summary of the invention

[0005] One of the purposes of the embodiments of the present application is to provide a method for determining battery impedance, an electronic device, and a computer-readable storage medium, which can timely and accurately update the impedance of the battery, thereby realizing accurate prediction of the remaining capacity of the battery.

[0006] A battery provided according to an embodiment of the present application includes: obtaining a first voltage Vn, a first current In and a first temperature Tn of the battery at a time point Dn, wherein n=0, 1, 2, 3..., and n is a non-negative integer; determining a first depth of discharge DODn of the battery at the time point Dn based on the first voltage Vn, the first current In and the first temperature Tn; and determining a first impedance Rn based on the first depth of discharge DODn determined at the time point Dn.

[0007] In some embodiments of the present application, when the first depth of discharge DODn is equal to the first ratio q1, a linear regression calculation is performed on the first impedance Rn to obtain the second impedance R1n.

[0008] In some embodiments of the present application, when the first discharge depth DODn is greater than the first ratio q1 and less than or equal to the second ratio q2, and when the first discharge depth DODn=q1+i×q3, where q3 is a third ratio, i=1,2,3..., i is a positive integer, a linear regression calculation is performed on the first impedance Rn to obtain a third impedance R2n, where the first ratio q1 is less than the second ratio q2.

[0009] In some embodiments of the present application, when the first discharge depth DODn is greater than the second ratio q2, and when the first discharge depth DODn=q2+i×q4, where q4 is a fourth ratio, a linear regression calculation is performed on the first impedance Rn to obtain a fourth impedance R3n.

[0010] In some embodiments of the present application, the value of the time point D0 is determined according to the response rate of the concentration impedance of the battery.

[0011] In some embodiments of the present application, the value of the time point D0 ranges from 500 seconds to 800 seconds.

[0012] In some embodiments of the present application, the third ratio q3 is not equal to the fourth ratio q4.

[0013] In some embodiments of the present application, the first ratio q1 is equal to 10%, and the second ratio q2 is in the range of 70% to 80%.

[0014] In some embodiments of the present application, the third ratio q3 ranges from 8% to 12%, and the fourth ratio q4 ranges from 2% to 5%.

[0015] In some embodiments of the present application, when the first depth of discharge DODn is less than the first ratio q1, the step of determining the first impedance Rn at the time point Dn includes: determining the first impedance Rn of the battery at the time point Dn based on the first aging parameter A0 of the battery, wherein the first aging parameter A0 is an aging parameter of the battery in a static state.

[0016] In some embodiments of the present application, it further includes determining a second aging parameter An of the battery at a time point Dn based on the obtained second impedance R1n when the first depth of discharge DODn is equal to the first ratio q1.

[0017] In some embodiments of the present application, it further includes when the first discharge depth DODn is greater than the first ratio q1 and less than or equal to the second ratio q2, whenever the third impedance R2n is obtained, determining the second aging parameter An of the battery at the time point Dn based on the obtained third impedance R2n.

[0018] In some embodiments of the present application, it further includes when the first discharge depth DODn is greater than the second ratio q2, whenever the fourth impedance R3n is obtained, determining the second aging parameter An of the battery at the time point Dn based on the obtained fourth impedance R3n.

[0019] In some embodiments of the present application, the first impedance Rn+1 of the battery at the time point Dn+1 is determined based on the second aging parameter An of the battery at the time point Dn.

[0020] In some embodiments of the present application, the relationship between the first voltage Vm of the battery at the second discharge depth DODm and the discharged charge Qm of the battery at the second discharge depth DODm is determined based on the second aging parameter An and the second discharge depth DODm of the battery, wherein the second discharge depth DODm of the battery is equal to or greater than the first discharge depth DODn, and m=0,1,2,3..., m is a non-negative integer.

[0021] In some embodiments of the present application, there is a fifth ratio q5 between DODm+1 and DODm.

[0022] In some embodiments of the present application, the fifth ratio q5 ranges from 3% to 8%.

[0023] In some embodiments of the present application, determining the relationship between the first voltage Vm of the battery at the second discharge depth DODm and the discharged charge Qm of the battery at the second discharge depth DODm also includes: determining the temperature rise model of the battery based on the second impedance R1n, the third impedance R2n or the fourth impedance R3n.

[0024] In some embodiments of the present application, it further includes determining a maximum depth of discharge DODmax when the first voltage Vm of the battery is equal to a cut-off voltage Vterm of the battery.

[0025] In some embodiments of the present application, the remaining charge Qres of the battery at the second discharge depth DODm is determined based on the maximum discharge depth DODmax, the second discharge depth DODm, and the maximum charge capacity Qmax of the battery.

[0026] In some embodiments of the present application, the full charge capacity FCC of the battery is determined based on the determined remaining charge Qres at the second discharge depth DODm, the discharged charge Qm at the second discharge depth DODm, and the discharged charge Q0 at the first discharge depth DOD0.

[0027] In some embodiments of the present application, the state of charge SOC of the battery is determined based on the determined remaining charge Qres at the second depth of discharge DODm and the determined full charge capacity FCC of the battery.

[0028] According to one embodiment of the present application, an electronic device is provided, which includes: a processor; a memory and a computer program stored in the memory and executable on the processor; the processor, the memory and the computer program are configured to enable the electronic device to implement the following steps: obtaining a first voltage Vn, a first current In and a first temperature Tn of a battery at a time point Dn, wherein n=0, 1, 2, 3..., and n is a non-negative integer; determining a first depth of discharge DODn of the battery at a time point Dn based on the obtained first voltage Vn, first current In and first temperature Tn; determining a first impedance Rn at a time point Dn based on the first depth of discharge DODn determined at the time point Dn.

[0029] According to an embodiment of the present application, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the method described in any of the above embodiments is implemented.

[0030] The method for determining battery impedance, the electronic device, and the computer-readable storage medium provided in the embodiments of the present application can timely and accurately update the impedance of the battery and realize accurate prediction of the remaining capacity of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The following will briefly describe the drawings necessary for describing the embodiments of the present application or the prior art to facilitate the description of the embodiments of the present application. Obviously, the drawings described below are only some of the embodiments in the present application. For those skilled in the art, without the need for creative work, drawings of other embodiments can still be obtained based on the structures illustrated in these drawings.

[0032] Figure 1 A schematic diagram of the structure of an electronic device according to an embodiment of the present application

[0033] Figure 2 A flowchart of a method for determining battery impedance according to an embodiment of the present application

[0034] Figure 3 A graph showing the battery discharge depth, battery operating voltage and open circuit voltage according to an embodiment of the present application.

[0035] Figure 4 A graph showing the discharged charge of a battery, the actual working voltage of the battery, the simulated working voltage of the battery, and the open circuit voltage of the battery according to an embodiment of the present application.

[0036] Figure 5 To obtain according to an embodiment of the present application Figure 4 A flow chart of a method for generating a curve diagram of a battery discharged charge and a battery simulation working voltage

[0037] Figure 6 A flowchart of a method for determining the remaining charge of a battery according to an embodiment of the present application

[0038] Figure 7 A flowchart of a method for determining a battery full charge capacity according to an embodiment of the present application

[0039] Figure 8 A flowchart of a method for determining a battery state of charge according to an embodiment of the present application

[0040] Fig. 9 A module diagram of a battery impedance determination device according to an embodiment of the present application

[0041] Fig.10 A schematic diagram of a circuit diagram of a battery impedance determination device according to an embodiment of the present application DETAILED DESCRIPTION

[0042] The embodiments of the present application will be described in detail below. In the full text of the present application specification, the same or similar components and components with the same or similar functions are represented by similar reference numerals. The embodiments of the accompanying drawings described herein are illustrative, graphical, and are used to provide a basic understanding of the present application. The embodiments of the present application should not be interpreted as limiting the present application.

[0043] As used herein, the terms "about", "substantially", are used to describe and illustrate small variations. When used in conjunction with an event or circumstance, the term may refer to instances where the event or circumstance occurred exactly as well as instances where the event or circumstance occurred very approximately. For example, when used in conjunction with a numerical value, the term may refer to a range of variation less than or equal to ±10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±0.5%, or less than or equal to ±0.05%. For example, if the difference between two numerical values ​​is less than or equal to ±10% of the average of the values, then the two numerical values ​​may be considered to be "substantially" the same.

[0044] Furthermore, for ease of description, “first”, “second”, “third”, etc. may be used herein to distinguish different components in one figure or a series of figures. “First”, “second”, “third”, etc. are not intended to describe the corresponding components.

[0045] In the present application, unless otherwise specified or limited, the terms "set", "connect", "couple", "fixed" and similar terms are used broadly, and those skilled in the art can understand that the above terms can be, for example, fixed connection, detachable connection or integrated connection according to the specific circumstances; it can also be a mechanical connection or an electrical connection; it can also be a direct connection or an indirect connection through an intermediate structure; it can also be an internal communication between two components.

[0046] Figure 1 FIG. 1 is a structural diagram of an electronic device 100 according to an embodiment of the present application.

[0047] like Figure 1 As shown, the electronic device 100 includes: a memory 10, at least one processor 11, a battery 12, an analog-to-digital converter 13 and a sensor 14. The above components can be connected via a bus or directly. A battery impedance determination module 15 runs in the electronic device 100.

[0048] It should be noted that Figure 1 The electronic device 100 is merely an example. In other embodiments, the electronic device 100 may include more or fewer components, or have a different component configuration. The electronic device 100 may be an electric motorcycle, an electric bicycle, an electric car, a mobile phone, a tablet computer, a digital assistant, a personal computer, or any other suitable rechargeable device.

[0049] The battery 12 is a rechargeable battery used to provide electrical energy to the electronic device 100. For example, the battery 12 may be a lead-acid battery, a nickel-cadmium battery, a nickel-metal hydride battery, a lithium-ion battery, a lithium polymer battery, and a lithium iron phosphate battery. The battery 12 is logically connected to the processor 11 through a battery management system (BMS), so that functions such as charging and discharging are realized through the battery management system. The battery management system can be connected to the energy storage inverter (PCS) via CAN or RS485. The battery 12 includes a battery cell (not shown).

[0050] The analog-to-digital converter 13 is used to measure the voltage and current of the battery cell of the battery 12 during charging, discharging, or standing. In this embodiment, the analog-to-digital converter 13 includes a digital filter. The digital filter is used to filter the voltage and current of the battery cell of the battery 12 during charging, discharging, or standing. In one embodiment, the digital filter may be a first-order low-pass filter. The analog-to-digital converter 13 needs to process the collected data, such as filtering. The analog-to-digital converter 13 cannot collect data during the processing interval of the collected data, resulting in a dead time in the analog-to-digital converter 13. The analog-to-digital converter 13 is a hardware circuit located in the entire device 100. The analog-to-digital converter 13 can independently collect, process and convert the required relevant data. The analog-to-digital converter 13 can collect, process and convert the required relevant data together with the processor 11.

[0051] The sensor 14 is used to measure the temperature of the battery cell of the battery 12 during charging, discharging, or standing. In one embodiment, the sensor 14 may be a negative temperature coefficient (NTC) thermistor. It is understood that the electronic device 100 may also include other devices, such as a pressure sensor, a light sensor, a gyroscope, a hygrometer, an infrared sensor, etc.

[0052] The battery impedance determination module 15 may include a software module stored in, for example, the memory 10 . The battery impedance determination module 15 may be executed by the processor 11 .

[0053] In other embodiments, the battery impedance determination module 15 is a hardware circuit located in the entire device 100, or a software module located in the processor 11. The battery impedance determination module 15 can be embodied using a hardware circuit. The battery impedance determination module 15 can independently embody a method for determining battery impedance. The battery impedance determination module 15 can embody a method for determining battery impedance together with the processor 11.

[0054] Figure 2 FIG. 1 is a flow chart of a method for determining battery impedance according to an embodiment of the present application. Figure 2 As shown, the method for determining the battery impedance may include the following steps:

[0055] Step S20, storing the relevant battery parameters in the memory of the electronic device.

[0056] In this embodiment, the battery parameters may include: the corresponding relationship between the battery open circuit voltage OCV and the battery discharge depth DOD, the battery temperature T and the battery aging parameter A: OCV = f (DOD, T, A); the corresponding relationship between the battery discharge depth DOD and the battery open circuit voltage OCV, the battery temperature T and the battery aging parameter A: DOD = g (OCV, T, A); the corresponding relationship between the battery impedance R and the battery discharge depth DOD, the battery temperature T and the battery aging parameter A: R = h (DOD, T, A); the corresponding relationship between the pre-initial state of charge Pre_SOC0 of the battery when it is just powered on and the battery voltage and battery temperature: Pre_SOC0 = LookUp (V, T). In other embodiments, the battery parameters may also include any required corresponding relationship and / or battery related parameters.

[0057] In this embodiment, the relevant battery parameters are stored in the memory of the electronic device. In other embodiments, the relevant battery parameters can be stored in the memory of the electronic device and the random access memory of the electronic device.

[0058] Step S21, obtaining a first voltage Vn, a first current In, and a first temperature Tn of the battery at a time point Dn.

[0059] In this embodiment, n is set to a non-negative integer equal to 0, 1, 2, 3... Set D0, D1, D2, D3...Dn-1, Dn, Dn+1 as time points, and the time points Dn-1 and Dn may differ by a fixed value or a non-fixed value. The first voltage Vn represents the operating voltage of the battery at the time point Dn, the first current In represents the operating current of the battery at the time point Dn, and the first temperature Tn represents the temperature of the battery at the time point Dn. For example, the first voltage V0 represents the operating voltage of the battery at the time point D0, the first current I0 represents the operating current of the battery at the time point D0, and the first temperature T0 represents the temperature of the battery at the time point D0.

[0060] The obtaining of the first voltage Vn, the first current In, and the first temperature Tn of the battery at the time point Dn may be the obtaining of the first voltage Vn and the first current In collected at the time point Dn by an analog-to-digital converter, and the obtaining of the first temperature Tn collected at the time point Dn by a sensor. In other embodiments, the obtaining of the first voltage Vn, the first current In, and the first temperature Tn of the battery at the time point Dn may be the obtaining of the first voltage Vn, the first current In, and the first temperature Tn collected at the time point Dn by any suitable device.

[0061] Step S22: determining a first depth of discharge DODn of the battery at a time point Dn based on the acquired first voltage Vn, first current In and first temperature Tn.

[0062] Determining the first depth of discharge DODn of the battery at time point Dn comprises:

[0063] A1: Determine the initial state of charge SOC0 of the battery in a static state before charging or discharging.

[0064] Determining the initial state of charge SOC0 of the battery in a static state before charging or discharging includes:

[0065] a1: determining a pre-initial state of charge Pre_SOC0 of the battery when it is just powered on according to a first voltage Vn, a first current In and a first temperature Tn of the battery when it is just powered on.

[0066] In the present embodiment, determining the pre-initial state of charge Pre_SOC0 of the battery when it is powered on according to the first voltage Vn, the first current In and the first temperature Tn of the battery when it is just powered on includes: determining the pre-initial state of charge Pre_SOC0 that matches the first voltage Vn and the first temperature Tn when it is just powered on according to the pre-stored correspondence between the battery voltage and temperature and the pre-initial state of charge Pre_SOC0.

[0067] In this embodiment, the pre-stored corresponding relationship between the battery voltage and temperature and the pre-initial state of charge Pre_SOC0 can be a relationship table Pre_SOC0=LookUp(Vn, ​​Tn), where Vn is the battery voltage when just powered on, and Tn is the battery temperature when just powered on. In other embodiments, the pre-stored corresponding relationship between the battery voltage and temperature and the pre-initial state of charge Pre_SOC0 can be a curve graph.

[0068] a2: Determine the effective open circuit voltage Valid_OCVn of the battery at time point Dn according to the pre-initial state of charge Pre_SOC0.

[0069] The method of determining the effective open circuit voltage Valid_OCVn of the battery at the time point Dn according to the pre-initial state of charge Pre_SOC0 includes: after the battery is powered on for a period of time (the specific value can be determined according to different battery models), the effective open circuit voltage of the battery is determined according to the first voltage Vn, the first current In and the first temperature Tn obtained at the time point Dn by the open circuit voltage method, that is, the formula Valid_OCVn=Vn-In×R(Pre_SOC0,Tn). Wherein Valid_OCVn is the effective open circuit voltage of the battery at the time point Dn, Vn is the first voltage of the battery at the time point Dn, In is the first current of the battery at the time point Dn, R(Pre_SOC0,Tn) is the battery impedance, and R(Pre_SOC0,Tn) is determined according to the pre-stored correspondence table between the pre-initial state of charge Pre_SOC0 and the temperature and the battery impedance.

[0070] a3: Determine the initial state of charge SOC0 according to the effective open circuit voltage Valid_OCVn.

[0071] Determining the initial state of charge SOC0 according to the effective open circuit voltage Valid_OCVn includes: determining the initial state of charge SOC0 according to the effective open circuit voltage Valid_OCVn of the battery at the time point Dn and the first temperature Tn at the time point Dn. Determining the initial state of charge SOC0 according to the effective open circuit voltage Valid_OCVn of the battery at the time point Dn and the first temperature Tn at the time point Dn includes: determining the initial state of charge SOC0 matching the effective open circuit voltage Valid_OCV and temperature at the time point Dn according to the pre-stored correspondence between the effective open circuit voltage Valid_OCV and temperature of the battery and the initial state of charge SOC0.

[0072] In this embodiment, the correspondence between the pre-stored effective open circuit voltage Valid_OCV and temperature of the battery and the initial state of charge SOC0 can be a relationship table SOC0=LookUp(Valid_OCVn,Tn). Valid_OCVn is the effective open circuit voltage Valid_OCVn of the battery at time point Dn, and Tn is the first temperature Tn of the battery at time point Dn. In other embodiments, the correspondence between the pre-stored effective open circuit voltage Valid_OCV and temperature of the battery and the initial state of charge SOC0 can be a curve graph.

[0073] a4: Repeat the above steps a2 and a3 to obtain an accurate initial state of charge SOC0.

[0074] A2: Determine the battery state of charge SOCn at time point Dn.

[0075] The determining of the battery state of charge SOCn at the time point Dn comprises: determining the battery state of charge SOCn at the time point Dn by the Coulomb integration method SOCn=SOC0+In×△t / Qmax. Wherein SOC0 is the initial state of charge determined in the aforementioned steps a1 to a4, In is the first current at the time point Dn, △t is the difference between Dn and D0, and △t is greater than 0, and Qmax is the maximum capacity of the battery, which is a fixed value when the battery leaves the factory.

[0076] A3: Determine a first depth of discharge DODn at time point Dn.

[0077] The determining of the first depth of discharge DODn at the time point Dn comprises: after determining the battery state of charge SOCn at the time point Dn, determining the first depth of discharge DODn at the time point Dn by a formula DODn=1-SOCn.

[0078] Step S23: determining a first impedance Rn at the time point Dn based on the first discharge depth DODn determined at the time point Dn.

[0079] The determining of the first impedance Rn at the time point Dn based on the first discharge depth DODn determined at the time point Dn includes: determining the first impedance Rn according to the formula Rn(DODn, Tn, An) = (OCV(DODn, Tn, An) - Vn) / In. Where DODn is the first discharge depth of the battery at the time point Dn; Tn is the first temperature of the battery at the time point Dn; An is the aging parameter of the battery at the time point Dn; In is the first current of the battery at the time point Dn; OCV(DODn, Tn, An) is the open circuit voltage of the battery at the time point Dn, and OCV(DODn, Tn, An) is determined according to the corresponding relationship between the open circuit voltage OCV of the battery and the discharge depth DOD of the battery, the battery temperature and the battery aging parameter. In this embodiment, the determining of the first impedance Rn according to the formula Rn(DODn, Tn, An) = (OCV(DODn, Tn, An) - Vn) / In includes:

[0080] b1: Determine the starting time point D0 for impedance calculation.

[0081] There is a polarization effect when the battery switches from a static state to a charge-discharge state, or from a charge-discharge state to a static state. In order to minimize the influence of the polarization effect, the starting time point D0 of the impedance calculation can be determined according to the response rate of the concentration impedance of the battery.

[0082] like Figure 3 As shown, Figure 3 The graph of the battery discharge depth DODn, the battery operating voltage Vn and the open circuit voltage OCV according to an embodiment of the present application, wherein the horizontal axis represents the battery discharge depth DOD, in percentage, and the vertical axis represents the voltage V, in volts. Curve I is a curve showing the change of the battery open circuit voltage OCV with the battery discharge depth DOD, and curve II is a curve showing the change of the battery operating voltage Vn with the battery discharge depth DOD.

[0083] In this embodiment, in order to prevent the disturbance caused by instantaneous loading, the starting time point D0 of the impedance calculation is selected to be about 600 seconds after loading, that is, D0 = about 600 seconds. In other embodiments, the value range of the time point D0 is determined according to the response rate of the concentration impedance of the specific battery, for example, about 500 seconds to about 800 seconds.

[0084] b2: Determine the value of the time interval Dn-Dn-1 for calculating the impedance Rn.

[0085] In order to more accurately calculate the battery impedance Rn, this embodiment sets the value of the time interval Dn-Dn-1 for calculating the impedance Rn under the consideration of the ohmic impedance, electrochemical impedance and concentration impedance of the battery. In this embodiment, the value of the time interval Dn-Dn-1 may be about 60 seconds. In other embodiments, the value of the time interval Dn-Dn-1 may be set according to the ohmic impedance, electrochemical impedance and concentration impedance of the battery, for example, about 100 seconds.

[0086] b3: When the first depth of discharge DODn is less than the first ratio q1, the first impedance Rn at the time point Dn is determined.

[0087] In this embodiment, the first ratio q1 = 10%. In other embodiments, q can be set to any appropriate value.

[0088] When the first depth of discharge DODn is less than the first ratio q1, determining the first impedance Rn at the time point Dn includes: calculating the first impedance Rn once every 60 seconds according to the formula Rn(DODn,Tn,An)=(OCV(DODn,Tn,An)-Vn) / In. Wherein DODn is the first depth of discharge of the battery at the time point Dn; Tn is the first temperature of the battery at the time point Dn; A0 is the first aging parameter A0 of the battery, that is, the aging parameter of the battery in a static state, which can be regarded as a known value; In is the first current of the battery at the time point Dn; OCV(DODn,Tn,A0) is the open circuit voltage of the battery at the time point Dn, and OCV(DODn,Tn,A0) is determined according to the corresponding relationship between the open circuit voltage OCV of the battery and the depth of discharge DOD, the battery temperature T and the battery aging parameter A of the battery.

[0089] b4: When the first depth of discharge DODn is equal to the first ratio q1, the second impedance R1n and the second aging parameter An are determined.

[0090] When the first discharge depth DODn is equal to the first ratio q1, the second impedance R1n is determined by performing a linear regression calculation on the first impedance Rn obtained during the period from the discharge depth DOD0 to the discharge depth DODn being equal to the first ratio q1, so as to obtain the second impedance R1n. The linear regression equation is: y=w×x+b, where y is the second impedance R1n when DODn is equal to the first ratio q1, x is the first ratio q1, i and N are positive integers greater than or equal to 1.

[0091] When the first depth of discharge DODn is equal to the first ratio q1, determining the second aging parameter An includes: determining the second aging parameter An of the battery at the time point Dn based on the obtained second impedance R1n. Determining the second aging parameter An of the battery at the time point Dn based on the obtained second impedance R1n includes:

[0092] According to the correspondence between the pre-stored battery aging parameter A and the battery impedance R, the second aging parameter of the battery when the first discharge depth DODn is equal to the first ratio q1 is determined. Among them, REOL (DODn, Tn) is the impedance of the battery when the battery capacity retention rate reaches 80% of the design capacity. It is measured under laboratory conditions and placed in the memory as reference data. It can be determined based on the corresponding relationship between the battery discharge depth and temperature and the battery impedance pre-stored in the memory; RNEW (DODn, Tn) is the impedance of the battery when it leaves the factory. It is measured under laboratory conditions and placed in the memory as reference data. It can be determined based on the corresponding relationship between the battery discharge depth and temperature and the battery impedance pre-stored in the memory; R1n (DODn, Tn) is the battery impedance when the first discharge depth DODn is equal to the first ratio q1, which is determined based on the above-mentioned linear regression calculation.

[0093] Therefore, after determining the second aging parameter An of the battery at time point Dn, the first impedance Rn+1 of the battery at time point Dn+1 can be further determined based on the second aging parameter An. Therefore, the method for determining the battery impedance provided by the embodiment of the present application can timely take into account the aging parameters of the battery and the operating temperature of the battery, thereby improving the accuracy of determining the battery impedance.

[0094] b5: When the first depth of discharge DODn is greater than the first ratio q1 and less than or equal to the second ratio q2, the first impedance Rn at the time point Dn is determined.

[0095] In this embodiment, the first ratio q1 is smaller than the second ratio q2, and the second ratio q2 = 80%. In other embodiments, the second ratio q2 can be set to any appropriate value, such as f = 70% to 80%.

[0096] When the first discharge depth DODn is greater than the first ratio q1 and less than or equal to the second ratio q2, determining the first impedance Rn at the time point Dn includes: calculating the first impedance Rn once every 60 seconds according to the formula Rn(DODn,Tn,An)=(OCV(DODn,Tn,An)-Vn) / In. Where DODn is the first discharge depth of the battery at the time point Dn; Tn is the first temperature of the battery at the time point Dn; In is the first current of the battery at the time point Dn; and when the first discharge depth DODn is greater than the first ratio q1 and less than or equal to the second ratio q2, and when the first discharge depth DODn=q1+i×q3, where q3 is the third ratio, i=1,2,3..., i is a positive integer, the battery aging parameter An will be updated once based on the linearly calculated first impedance Rn, so An here is the latest updated battery aging parameter, and its calculation method is described in detail as follows. OCV (DODn, Tn, An) is the open circuit voltage of the battery at the time point Dn, which is determined according to the corresponding relationship between the open circuit voltage OCV of the battery and the depth of discharge DOD of the battery, the battery temperature T and the battery aging parameter A.

[0097] In this embodiment, the third ratio q3 = 10%. In other embodiments, the third ratio q3 can be set to any appropriate value, for example, 8% to 12%.

[0098] b6: When the first depth of discharge DODn is greater than the first ratio q1 and less than or equal to the second ratio q2, the third impedance R2n and the second aging parameter An are determined.

[0099] When the first discharge depth DODn is greater than the first ratio q1 and less than or equal to the second ratio q2, the determination of the third impedance R2n includes: when the first discharge depth DODn=q1+i×q3, a linear regression calculation is performed on all first impedances Rn obtained in the time period when the discharge depth increases from the third ratio q3 to the first discharge depth DODn=q1+i×q3 to obtain the third impedance R2n. The linear regression equation is: y=w×x+b, where y is the third impedance R2n when DODn increases by the third ratio q3, x is the DODn when the third ratio q3 increases, i and N are positive integers greater than or equal to 1.

[0100] When the first depth of discharge DODn is greater than the first ratio q1 and less than or equal to the second ratio q2, the determining of the third aging parameter A2 includes: determining the second aging parameter An of the battery at the time point Dn based on the obtained second impedance R2n. The determining of the second aging parameter An of the battery at the time point Dn based on the obtained second impedance R2n includes:

[0101] According to the correspondence between the pre-stored battery aging parameter A and the battery impedance R, the second aging parameter of the battery is determined when the first discharge depth DODn is greater than the first ratio q1 and less than or equal to the second ratio q2, and when the first discharge depth DODn = q1 + i × q3 Among them, REOL (DODn, Tn) is the impedance of the battery when the battery capacity retention rate reaches 80% of the design capacity. It is measured under laboratory conditions and placed in the memory as reference data. It can be determined based on the corresponding relationship between the battery discharge depth and temperature and the battery impedance pre-stored in the memory; RNEW (DODn, Tn) is the impedance of the battery at the time of leaving the factory. It is measured under laboratory conditions and placed in the memory as reference data. It can be determined based on the corresponding relationship between the battery discharge depth and temperature and the battery impedance pre-stored in the memory; R2n (DODn, Tn) is the battery impedance corresponding to the first discharge depth DODn when the battery is greater than the first ratio q1 and less than or equal to the second ratio q2 and when the first discharge depth DODn = q1 + i × q3, which is determined based on the above-mentioned linear regression calculation.

[0102] That is, when the first depth of discharge DODn is greater than the first ratio q1 and less than or equal to the second ratio q2, the second aging parameter An is updated every time the third impedance R2n is obtained. Therefore, when the first impedance Rn is calculated according to the formula Rn(DODn,Tn,An)=(OCV(DODn,Tn,An)-Vn) / In every 60 seconds, the battery impedance can be determined based on the latest determined battery aging parameter, that is, the first impedance Rn+1 of the battery at the time point Dn+1 is determined based on the second aging parameter An of the battery at the time point Dn, thereby improving the accuracy of the battery impedance determination.

[0103] b7: When the first depth of discharge DODn is greater than the second ratio q2, the first impedance Rn at the time point Dn is determined.

[0104] When the first depth of discharge DODn is greater than the second ratio q2, determining the first impedance Rn at the time point Dn includes: calculating the first impedance Rn once every 60 seconds according to the formula Rn(DODn,Tn,An)=(OCV(DODn,Tn,An)-Vn) / In. Wherein DODn is the first depth of discharge of the battery at the time point Dn; Tn is the first temperature of the battery at the time point Dn; In is the first current of the battery at the time point Dn, and when the first depth of discharge DODn is greater than the first ratio q1 and less than or equal to the second ratio q2, and when the first depth of discharge DODn=q2+i×q4, where q4 is the fourth ratio, the battery aging parameter An will be updated once based on the linearly calculated first impedance Rn, so An here is the latest updated battery aging parameter, and its calculation method is described in detail as follows. OCV (DODn, Tn, An) is the open circuit voltage of the battery at the time point Dn, which is determined according to the corresponding relationship between the open circuit voltage OCV of the battery and the depth of discharge DOD of the battery, the battery temperature T and the battery aging parameter A.

[0105] In this embodiment, the fourth value = 3%. In other embodiments, the fourth value can be set to any appropriate value, for example, 2% to 5%. Since the battery impedance at the end of discharge varies greatly, the fourth value can be set according to actual conditions to improve the accuracy of the calculation.

[0106] b8: When the first depth of discharge DODn is greater than the second ratio q2, the fourth impedance R3n and the second aging parameter An are determined.

[0107] When the first discharge depth DODn is greater than the second ratio q2, the determination of the fourth impedance R3n includes: when the first discharge depth DODn=q2+i×q4, performing a linear regression calculation on all first impedances Rn obtained in a time period when the discharge depth increases by a fourth value, so as to obtain the fourth impedance R3n. The linear regression equation is: y=w×x+b, wherein y is the fourth impedance R3n when DODn increases by a fourth value, x is the DODn when it increases by a fourth value, i and N are positive integers greater than or equal to 1.

[0108] When the first depth of discharge DODn is greater than the second ratio q2, determining the second aging parameter An includes: determining the second aging parameter An of the battery at the time point Dn based on the obtained fourth impedance R3n. Determining the second aging parameter An of the battery at the time point Dn based on the obtained fourth impedance R3n includes:

[0109] According to the pre-stored corresponding table of the relationship between the battery aging parameter A and the battery impedance R, the second aging parameter of the battery when the first discharge depth DODn is greater than the second ratio q2 and the first discharge depth DODn = q2 + i × q4 is determined. Among them, REOL (DODn, Tn) is the impedance of the battery when the battery capacity retention rate reaches 80% of the design capacity. It is measured under laboratory conditions and placed in the memory as reference data. It can be determined based on the corresponding relationship between the battery discharge depth and temperature and the battery impedance pre-stored in the memory; RNEW (DODn, Tn) is the impedance of the battery at the time of leaving the factory. It is measured under laboratory conditions and placed in the memory as reference data. It can be determined based on the corresponding relationship between the battery discharge depth and temperature and the battery impedance pre-stored in the memory; R3n (DODn, Tn) is the battery impedance corresponding to the first discharge depth DODn greater than the second ratio q2 and when the first discharge depth DODn = q2 + i × q4, which is determined based on the above-mentioned linear regression calculation.

[0110] That is, when the first depth of discharge DODn is greater than the second ratio q2, the second aging parameter An is updated every time the fourth impedance R3n is obtained. Therefore, when the first impedance Rn is calculated according to the formula Rn(DODn, Tn, An) = (OCV(DODn, Tn, An) - Vn) / In at every 60 seconds, the impedance of the battery can be updated based on the latest determined aging parameter of the battery, that is, the first impedance Rn+1 of the battery at the time point Dn+1 is determined based on the second aging parameter An of the battery at the time point Dn, thereby improving the accuracy of the battery impedance determination.

[0111] Therefore, the embodiment of the present application takes into account the influence of battery aging factors and temperature factors, and can more accurately determine the impedances R0, R1, R2...Rn of the batteries at time points D0, D1, D2...Dn, and further obtain the second impedance R1n, the third impedance R2n and the fourth impedance R3n through linear regression calculation, so as to further more accurately update the battery impedance at the time point Dn, thereby improving the accuracy of the battery impedance determination.

[0112] In addition, when the impedance Rn at the time point Dn is updated to the second impedance R1n, the third impedance R2n or the fourth impedance R3n calculated by linear regression, a protection mechanism can be added to achieve filtering and limiting. For example, the formula Rnew=a×Rold+(1-a)×Rnew is used to achieve first-order low-pass filtering. Where a is the filter factor, Rnew is the impedance value at the current moment, and Rold is the impedance value at the previous moment. For example, the robustness design formula |Rnew-Rold|<△R is used to achieve limiting. Where △R is the maximum impedance change value allowed.

[0113] Figure 4 Graph showing the discharged charge Q of the battery, the actual working voltage Vn of the battery, the simulated working voltage Vm of the battery, and the open circuit voltage OCV of the battery according to an embodiment of the present application. Figure 4 As shown, the horizontal axis represents the battery discharged charge Q, in units of mAh, and the vertical axis represents the voltage, in units of volts (V). Curve I is a curve showing the change of the battery open circuit voltage OCV with the battery discharged charge Q, curve II is a curve showing the change of the battery actual working voltage Vn with the battery discharged charge Q, and curve III is a curve showing the change of the battery simulation working voltage Vm with the battery discharged charge Q.

[0114] Figure 5 To obtain according to an embodiment of the present application Figure 4 Flow chart of the method for plotting a graph of a battery discharged charge Q and a battery simulation operating voltage Vm.

[0115] Combination Figure 4 and Figure 5 ,get Figure 4 The method for plotting a graph of the battery discharged charge Q and the battery simulation working voltage Vm may include the following steps:

[0116] Step S50, determining a first impedance Rn at time point Dn.

[0117] The determining of the first impedance Rn at the time point Dn comprises: based on Figure 2 The illustrated method of determining the impedance of a battery determines a first impedance Rn at a time point Dn.

[0118] In this embodiment, when the discharged charge is equal to about 250 mAh, the battery has a discharge depth DOD0, and the corresponding discharged charge is marked as Q0. The time corresponding to the discharge depth DOD0 is the starting time point D0 of the impedance calculation.

[0119] When the discharged charge Q is equal to 1000 mAh, the battery has a discharge depth DODn. Here, the discharged charge from the discharge depth DOD0 to the discharge depth DODn is marked as Qn. Figure 1 The electronic device and Figure 2 The method for determining the battery impedance shown in the figure determines the discharge depth DODn at the time point Dn, the second impedance R1n, the third impedance R2n and / or the fourth impedance R3n at the time point Dn to obtain the most accurate impedance at the time point Dn, and the second aging parameter An of the battery at the time point Dn, and by Figure 1 The electronic device shown obtains a first temperature Tn of the battery at a time point Dn, and a first current In of the battery at the time point Dn.

[0120] Step S51, starting the simulation of the working voltage Vm of the battery from the time point corresponding to the depth of discharge DODn.

[0121] The symbol DODm represents the discharge depth of the battery during the simulation process, that is, the second discharge depth DODm of the battery described in the embodiment of the present application, where m=0, 1, 2, 3..., m is a non-negative integer, and when m is equal to 0, DODm is equivalent to the discharge depth DODn corresponding to the start of the simulation. The second discharge depth DODm of the battery is equal to or greater than the first discharge depth DODn.

[0122] The starting of the battery operating voltage simulation from the time point corresponding to the discharge depth DODn includes: starting the battery operating voltage simulation from when m is equal to 0. During the battery voltage simulation process, the battery discharge depth increases at a rate of 5%. That is, there is a fixed fifth ratio q5 between DODm+1 and DODm. In this embodiment, DODm+1=DODm+5%, that is, the fifth ratio q5 is 5%. In other embodiments, the fifth ratio q5 ranges from 3% to 8%.

[0123] Step S52, determining a first voltage Vm of the battery at a depth of discharge DODm.

[0124] The method of determining the first voltage Vm of the battery at the discharge depth DODm includes: determining the first voltage Vm of the battery at the discharge depth DODm according to Ohm's law = OCV (DODm, Tm, An) - In × Rn (DODm, Tm, An). Wherein OCV (DODm, Tm, An) is the open circuit voltage of the battery at the discharge depth DODm; An is the second aging parameter determined when the battery is at the discharge depth DODn; In is the first current obtained when the battery is at the discharge depth DODn; and Rn (DODm, Tm, An) is the resistance that takes into account the battery aging parameter An determined when the battery is at the discharge depth DODn and the temperature Tm during the simulation process. Tm is the battery temperature during the simulation process.

[0125] In order to predict the temperature change during the simulation, a temperature rise model can be added: Where c is the specific heat capacity of the battery, m is the mass of the battery, T is the temperature of the battery, Tenv is the ambient temperature, is the entropy coefficient, h is the battery heat dissipation coefficient, S is the surface area of ​​the battery, and Rnew is based on Figure 2 The second impedance R1n, the third impedance R2n or the fourth impedance R3n at the time point Dn determined by the method for determining the battery impedance shown.

[0126] Step S53, stopping the simulation when the first voltage Vm of the battery is equal to the cut-off voltage Vterm of the battery.

[0127] In this embodiment, the cut-off voltage Vterm of the battery is a fixed value.

[0128] The open circuit voltage of the aged battery is lower than the open circuit voltage of the battery just leaving the factory. If the aging factor is not considered, the open circuit voltage value of the battery is too large, resulting in a larger initial discharge depth, which affects the accuracy of the subsequent battery impedance and battery capacity calculation. In addition, the battery impedance after aging is greater than the battery impedance just leaving the factory. If the aging factor is not considered, the resistance determined at the time point Dn will be too small, affecting the accuracy of the subsequent capacity calculation.

[0129] Moreover, at the same depth of discharge, the open circuit voltage at 0°C and the open circuit voltage at 25°C may differ by 50mV. If the temperature change is not considered, the calculation error of the depth of discharge will increase by 0.5%. Furthermore, temperature change has a greater impact on battery impedance. For example, at the same depth of discharge, the resistance determined at time point Dn at 0°C and the resistance determined at time point Dn at 25°C may differ by 150mΩ. If the temperature change is not considered, the calculation error of the resistance at time point Dn will increase by 15%.

[0130] Therefore, in the process of simulating the battery operating voltage changing with the battery discharged charge Q, the embodiment of the present application takes into account the battery aging factor and the temperature change factor during the battery charging and discharging process, and can accurately predict the change of the simulated battery operating voltage changing with the battery discharged charge Q to accurately display the power level.

[0131] Figure 6 FIG. 1 is a flow chart of a method for determining the remaining charge of a battery according to an embodiment of the present application. Figure 6 As shown, the method for determining the remaining charge of a battery may include the following steps:

[0132] Step S60, determining the maximum discharge depth DODmax.

[0133] The determining of the maximum discharge depth DODmax includes: stopping the simulation when the first voltage Vm of the battery is equal to the cut-off voltage Vterm of the battery, and determining the maximum discharge depth DODmax at this time.

[0134] Step S61: determining the remaining charge Qres of the battery at a first discharge depth DODn based on the maximum discharge depth DODmax.

[0135] The method of determining the residual charge Qres of the battery at the first discharge depth DODn based on the maximum discharge depth DODmax includes: determining the residual charge Qres = |DODmax-DODn| × Qmax of the battery at the first discharge depth DODn at the start of simulation based on the determined maximum discharge depth DODmax, the first discharge depth DODn at the start of simulation, and the maximum charge capacity Qmax of the battery, wherein the maximum charge capacity Qmax of the battery is a fixed value when the battery leaves the factory.

[0136] The remaining charge Qres of the battery at the first depth of discharge DODm can also be determined. Figure 4 As shown, the residual charge Qres of the battery at the second discharge depth DODm=|DODmax-DODm|×Qmax.

[0137] Figure 7 FIG. 1 is a flow chart of a method for determining a battery full charge capacity FCC according to an embodiment of the present application. Figure 7 As shown, the method for determining the full charge capacity FCC of a battery may include the following steps:

[0138] Step S70, determining the full charge capacity FCC of the battery = Q0 + Qn + Qres based on the determined residual charge Qres at the first depth of discharge DODn, the discharged charge Qn at the first depth of discharge DODn, and the discharged charge Q0 at the first depth of discharge DOD0.

[0139] The full charge capacity FCC=Q0+Qm+Qres of the battery may also be determined based on the determined remaining charge Qres at the first depth of discharge DODm, the discharged charge Qm at the first depth of discharge DODm, and the discharged charge Q0 at the first depth of discharge DOD0.

[0140] Figure 8 FIG. 1 is a flow chart of a method for determining a battery state of charge SOC according to an embodiment of the present application. Figure 8 As shown, the method for determining the battery state of charge SOC may include the following steps:

[0141] Step S80 , determining the state of charge SOC of the battery = Qres / FCC based on the determined residual charge Qres at the first depth of discharge DODn and the determined full charge capacity FCC of the battery.

[0142] Fig. 91 is a module diagram of a battery impedance determination device according to an embodiment of the present application. In one embodiment, in this embodiment, the battery impedance determination module 15 can be divided into one or more modules, and the one or more modules are contained in the memory 10. The battery impedance determination module 15 may include a software module (softwaremodule) stored in, for example, the memory 10. The battery impedance determination module 15 can be executed by the processor 11. In other embodiments, the battery impedance determination module 15 can be embodied using a hardware circuit. The battery impedance determination module 15 can independently embody a method for determining battery impedance. The battery impedance determination module 15 and the processor 11 can jointly embody a method for determining battery impedance.

[0143] like Fig. 9 As shown, the battery impedance determination module 15 can be divided into an acquisition module 901, a discharge depth determination module 902, a battery impedance determination module 903, and an aging parameter determination module 904. The acquisition module 901 can be used to acquire a first voltage Vn, a first current In, and a first temperature Tn of the battery at a time point Dn. The discharge depth determination module 902 can be used to determine a first discharge depth DODn of the battery at a time point Dn based on the acquired first voltage Vn, first current In, and first temperature Tn. The battery impedance determination module 903 can be used to determine a first impedance Rn at a time point Dn based on the first discharge depth DODn determined at the time point Dn. The aging parameter determination module 904 can be used to determine a second aging parameter An based on the determined first impedance Rn.

[0144] The battery impedance determination device of this embodiment can accurately and timely update the battery impedance. For details, please refer to the embodiment of the method for determining the battery impedance above, which will not be described in detail here.

[0145] In this embodiment, the memory 10 may be an internal memory of the electronic device 100, that is, a memory built into the electronic device 100. In other embodiments, the memory 10 may also be an external memory of the electronic device 100, that is, a memory external to the electronic device 100. In some embodiments, the memory 100 is used to store program codes, various data and computer programs, for example, a computer program for storing a battery impedance determination module 15 installed in the electronic device 100, which can be run on the processor, and the processor, the memory and the computer program are configured to enable the electronic device 100 to implement the above-mentioned method for determining battery impedance. The memory 10 may include a random access memory, and may also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0146] In one embodiment, the processor 11 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor, or the processor may be any other conventional processor, etc.

[0147] If the modules in the battery impedance determination module 15 are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the present application implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Me mory), electrical carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the content contained in the computer-readable medium may be appropriately increased or decreased according to the requirements of legislation and patent practices in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practices, computer-readable media do not include electrical carrier signals and telecommunication signals.

[0148] It is understandable that the module division described above is a logical function division, and there may be other division methods in actual implementation. In addition, the functional modules in each embodiment of the present application may be integrated in the same processing unit, or each module may exist physically separately, or two or more modules may be integrated in the same unit. The above-mentioned integrated modules may be implemented in the form of hardware or in the form of hardware plus software functional modules.

[0149] Fig.10 FIG. 1 is a schematic diagram of a circuit structure of a battery impedance determination device according to an embodiment of the present application. Fig.10 As shown, the battery impedance determination device circuit 200 includes: an acquisition circuit 201 and a parameter determination circuit 203 .

[0150] The acquisition circuit 201 acquires a first voltage Vn, a first current In, and a first temperature Tn of the battery at a time point Dn.

[0151] The parameter determination circuit 203 includes: a discharge depth determination circuit 203a, a battery impedance determination circuit 203b and an aging parameter determination circuit 203c.

[0152] The discharge depth determination circuit 203a may determine a first discharge depth DODn of the battery at a time point Dn based on the acquired first voltage Vn, first current In and first temperature Tn.

[0153] The battery impedance determination circuit 203b may determine a first impedance Rn at the time point Dn based on the first depth of discharge DODn determined at the time point Dn.

[0154] The aging parameter determination circuit 203c may determine a second aging parameter An based on the determined first impedance Rn.

[0155] The battery impedance determination device circuit of this embodiment can accurately and timely update the battery impedance. For details, please refer to the embodiment of the method for determining the battery impedance above, which will not be described in detail here. The battery impedance determination device circuit of this embodiment can be implemented by a combination of conventional circuit elements (for example, but not limited to, filters, amplifiers, etc.), which will not be described in detail here.

Claims

1. A method for determining battery impedance, include: Obtaining a first voltage Vn, a first current In, and a first temperature Tn of the battery at a time point Dn, where n=0, 1, 2, 3, ..., and n is a non-negative integer; Determine a first depth of discharge DODn of the battery at a time point Dn based on the first voltage Vn, the first current In and the first temperature Tn; determining a first impedance Rn based on the first discharge depth DODn determined at a time point Dn; When the first discharge depth DODn is equal to the first ratio q1, a linear regression calculation is performed on the first impedance Rn to obtain a second impedance R1n.

2. The method for determining battery impedance according to claim 1, wherein when the first depth of discharge DODn is greater than the first ratio q1 and less than or equal to the second ratio q2, and when the first depth of discharge DODn=q1+i×q3, where q3 is a third ratio, i=1,2,3..., i is a positive integer, a linear regression calculation is performed on the first impedance Rn to obtain a third impedance R2n, wherein the first ratio q1 is less than the second ratio q2.

3. The method for determining battery impedance according to claim 2, wherein when the first discharge depth DODn is greater than the second ratio q2, and when the first discharge depth DODn=q2+i×q4, where q4 is a fourth ratio, a linear regression calculation is performed on the first impedance Rn to obtain a fourth impedance R3n. 4 . The method for determining battery impedance according to claim 1 , wherein the value of time point D0 is determined according to a response rate of the concentration impedance of the battery. 5 . The method for determining battery impedance according to claim 4 , wherein the value of the time point D0 ranges from 500 seconds to 800 seconds. 6 . The method for determining battery impedance according to claim 3 , wherein the third ratio q3 is not equal to the fourth ratio q4 . 7 . The method for determining battery impedance according to claim 2 , wherein the first ratio q1 is 10%, and the second ratio q2 is in the range of 70% to 80%. 8 . The method for determining battery impedance according to claim 3 , wherein the third ratio q3 ranges from 8% to 12%, and the fourth ratio q4 ranges from 2% to 5%.

9. The method for determining battery impedance according to claim 1, wherein when the first discharge depth DODn is less than the first ratio q1, the step of determining the first impedance Rn at the time point Dn is: include: A first impedance Rn of the battery is determined based on a first aging parameter A0 of the battery, wherein the first aging parameter A0 is an aging parameter of the battery in a static state. 10 . The method for determining battery impedance according to claim 1 , further comprising determining a second aging parameter An of the battery based on the obtained second impedance R1 n when the first depth of discharge DODn is equal to the first ratio q1 .

11. The method for determining battery impedance according to claim 2, further comprising determining a second aging parameter An of the battery based on the obtained third impedance R2n whenever the third impedance R2n is obtained when the first depth of discharge DODn is greater than the first ratio q1 and less than or equal to the second ratio q2.

12. The method for determining battery impedance according to claim 3, further comprising determining a second aging parameter An of the battery based on the obtained fourth impedance R3n whenever the fourth impedance R3n is obtained when the first depth of discharge DODn is greater than the second ratio q2.

13. The method for determining battery impedance according to any one of claims 10 to 12, further comprising: include: A first impedance Rn+1 of the battery at a time point Dn+1 is determined based on a second aging parameter An of the battery.

14. The method of determining battery impedance according to claim 12, further comprising: include: The relationship between the first voltage Vm of the battery at the second depth of discharge DODm and the discharged charge Qm of the battery at the second depth of discharge DODm is determined based on the second aging parameter An and the second depth of discharge DODm of the battery, wherein the second depth of discharge DODm of the battery is equal to or greater than the first depth of discharge DODn, and m=0,1,2,3..., m is a non-negative integer. 15 . The method for determining battery impedance according to claim 14 , wherein DODm+1 differs from DODm by a fifth ratio q5 . 16 . The method for determining battery impedance according to claim 15 , wherein the fifth ratio q5 ranges from 3% to 8%.

17. The method for determining battery impedance according to claim 14, wherein the determining the relationship between the first voltage Vm of the battery at the second discharge depth DODm and the discharged charge Qm of the battery at the second discharge depth DODm further comprises: include: A temperature rise model of the battery is determined based on the second impedance R1n, the third impedance R2n or the fourth impedance R3n. 18 . The method of determining battery impedance according to claim 14 , further comprising determining a maximum depth of discharge DODmax when a first voltage Vm of the battery is equal to a cut-off voltage Vterm of the battery.

19. The method for determining battery impedance according to claim 18, wherein the remaining charge Qres of the battery at the second discharge depth DODm is determined based on the maximum discharge depth DODmax, the second discharge depth DODm, and the maximum charge capacity Qmax of the battery.

20. The method for determining battery impedance according to claim 19, further comprising: include: The full charge capacity FCC of the battery is determined based on the remaining charge Qres at the second depth of discharge DODm, the discharged charge Qm at the second depth of discharge DODm, and the discharged charge Q0 at the first depth of discharge DOD0.

21. The method for determining battery impedance according to claim 20, further comprising: include: The state of charge SOC of the battery is determined based on the determined remaining charge Qres at the second depth of discharge DODm and the determined full charge capacity FCC of the battery.

22. An electronic device, include: processor; and a memory and a computer program stored on the memory and executable on the processor; It is characterized in that the processor, the memory and the computer program are configured to enable the electronic device to implement the following steps: Obtaining a first voltage Vn, a first current In, and a first temperature Tn of the battery at a time point Dn, where n=0, 1, 2, 3, ..., and n is a non-negative integer; Determine a first depth of discharge DODn of the battery at a time point Dn based on the acquired first voltage Vn, first current In and first temperature Tn; Determining a first impedance Rn at a time point Dn based on the first discharge depth DODn determined at the time point Dn; When the first discharge depth DODn is equal to the first ratio q1, a linear regression calculation is performed on the first impedance Rn to obtain a second impedance R1n.

23. The electronic device according to claim 22, wherein when the first depth of discharge DODn is greater than the first ratio q1 and less than or equal to the second ratio q2, and when the first depth of discharge DODn=q1+i×q3, where q3 is a third ratio, i=1,2,3..., i is a positive integer, a linear regression calculation is performed on the first impedance Rn to obtain a third impedance R2n, wherein the first ratio q1 is less than the second ratio q2.

24. The electronic device according to claim 23, wherein when the first discharge depth DODn is greater than the second ratio q2, and when the first discharge depth DODn=q2+i×q4, where q4 is a fourth ratio, a linear regression calculation is performed on the first impedance Rn to obtain a fourth impedance R3n. 25 . The electronic device according to claim 22 , wherein the value of the time point D0 is determined according to a response rate of the concentration impedance of the battery. The electronic device according to claim 25 , wherein the value of the time point D0 ranges from 500 seconds to 800 seconds. The electronic device according to claim 24 , wherein the third ratio q3 is not equal to the fourth ratio q4 . 28 . The electronic device according to claim 23 , wherein the first ratio q1 is equal to 10%, and the second ratio q2 is in a range of 70% to 80%. 29 . The electronic device according to claim 24 , wherein the third ratio ranges from 8% to 12%, and the fourth ratio ranges from 2% to 5%.

30. The electronic device according to claim 22, wherein when the first discharge depth DODn is less than the first ratio q1, the step of determining the first impedance Rn at the time point Dn is: include: A first impedance Rn of the battery at a time point Dn is determined based on a first aging parameter A0 of the battery, wherein the first aging parameter A0 is an aging parameter of the battery in a static state. 31 . The electronic device according to claim 22 , further comprising determining a second aging parameter An of the battery at a time point Dn based on the obtained second impedance R1n when the first depth of discharge DODn is equal to the first ratio q1 .

32. The electronic device according to claim 23, further comprising determining a second aging parameter An of the battery at a time point Dn based on the obtained third impedance R2n whenever the third impedance R2n is obtained when the first depth of discharge DODn is greater than the first ratio q1 and less than or equal to the second ratio q2.

33. The electronic device according to claim 24, further comprising when the first depth of discharge DODn is greater than the second ratio q2, whenever the fourth impedance R3n is obtained, determining a second aging parameter An of the battery at a time point Dn based on the obtained fourth impedance R3n.

34. The electronic device according to any one of claims 31 to 33, further comprising: include: A first impedance Rn+1 of the battery at a time point Dn+1 is determined based on a second aging parameter An of the battery at a time point Dn.

35. The electronic device according to claim 33, further comprising: include: The relationship between the first voltage Vm of the battery at the second depth of discharge DODm and the discharged charge Qm of the battery at the second depth of discharge DODm is determined based on the second aging parameter An and the second depth of discharge DODm of the battery, wherein the second depth of discharge DODm of the battery is equal to or greater than the first depth of discharge DODn, and m=0,1,2,3..., m is a non-negative integer. The electronic device according to claim 35 , wherein DODm+1 differs from DODm by a fifth ratio q5 .

37. The electronic device according to claim 36, wherein the fifth ratio q5 ranges from 3% to 8%.

38. The electronic device according to claim 35, wherein the relationship between the first voltage Vm of the battery at the second discharge depth DODm and the discharged charge Qm of the battery at the second discharge depth DODm is determined. include: A temperature rise model of the battery is determined based on the second impedance R1n, the third impedance R2n or the fourth impedance R3n.

39. The electronic device of claim 35, further comprising determining a maximum depth of discharge DODmax when a first voltage Vm of the battery is equal to a cut-off voltage Vterm of the battery.

40. The electronic device of claim 39, wherein a remaining charge Qres of the battery at the second depth of discharge DODm is determined based on the maximum depth of discharge DODmax, the second depth of discharge DODm, and a maximum charge capacity Qmax of the battery.

41. The electronic device according to claim 40, further comprising: include: The full charge capacity FCC of the battery is determined based on the determined remaining charge Qres at the second depth of discharge DODm, the discharged charge Qm at the second depth of discharge DODm, and the discharged charge Q0 at the first depth of discharge DOD0.

42. The electronic device according to claim 41, further comprising: include: The state of charge SOC of the battery is determined based on the determined remaining charge Qres at the second depth of discharge DODm and the determined full charge capacity FCC of the battery.

43. A computer-readable storage medium having a computer program stored thereon, It is characterized in that When the computer program is executed by a processor, the method according to any one of claims 1 to 21 is implemented.

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