CN112485686A

CN112485686A - Method for determining battery impedance, electronic device and computer readable storage medium

Info

Publication number: CN112485686A
Application number: CN201910865485.3A
Authority: CN
Inventors: 谢洪; 孙亚青; 鲁丹丹
Original assignee: Dongguan Nvt Technology Co Ltd
Current assignee: Dongguan Nvt Technology Co Ltd
Priority date: 2019-09-12
Filing date: 2019-09-12
Publication date: 2021-03-12

Abstract

The present application relates to a method of determining battery impedance, an electronic device and a computer readable storage medium. A method of determining battery impedance according to one embodiment includes: acquiring a first voltage Vn, a first current In and a first temperature Tn of a battery at a time point Dn, wherein n is 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; the first impedance Rn is determined based on the first depth of discharge DODn determined at the point in time Dn. The method for determining the battery impedance, the electronic device and the computer-readable storage medium provided by the embodiment of the application can realize more accurate update of the battery impedance, so that the residual capacity of the battery can be accurately predicted.

Description

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

Technical Field

Embodiments of the present disclosure 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

At present, the lithium ion battery has the advantages of high energy density, high power density, multiple recycling times, long storage time and the like, and has wide application prospects in the aspects of large and medium-sized electric equipment such as electric vehicles and energy storage facilities, so the lithium ion battery becomes a key for solving global problems such as energy crisis, environmental pollution and the like.

In the using process of the lithium ion battery, the lithium ion battery can age gradually along with the time, and further the impedance of the lithium ion battery is obviously increased. If the impedance of the lithium ion battery cannot be updated in time, the accuracy of the electric quantity algorithm cannot be guaranteed, and further the residual capacity of the lithium ion battery is displayed inaccurately, so that the use of a user is influenced. For example, if the remaining capacity of the battery cannot be accurately predicted, the electric vehicle may lose kinetic energy while traveling on a highway, thereby causing a danger or an accident. For example, if the remaining capacity of the battery cannot be accurately predicted, it may not be possible to make a correct determination as to whether to charge the vehicle battery, and if the electric vehicle loses kinetic energy at a relatively long distance from the charging station (e.g., in a desert or wilderness), it may cause great inconvenience and even affect safety (e.g., lack of battery to provide heat energy in a low-temperature environment).

Therefore, there are many technical problems to be solved in the art regarding how to update the impedance of the battery timely and accurately.

Disclosure of Invention

An objective of the embodiments of the present disclosure is to provide a method, an electronic device and a computer-readable storage medium for determining an impedance of a battery, which can update the impedance of the battery timely and accurately, so as to achieve accurate prediction of a remaining capacity of the battery.

According to an embodiment of the present application, there is provided a battery including: acquiring a first voltage Vn, a first current In and a first temperature Tn of the battery at a time point Dn, wherein n is 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, a first current In and a first temperature Tn; a first impedance Rn is determined based on the first depth of discharge DODn determined at the point in time Dn.

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 a second impedance R1 n.

In some embodiments of the present application, when the first depth of discharge DODn is greater than the first proportion q1 and less than or equal to a second proportion q2, and when the first depth of discharge DODn is q1+ i × q3, where q3 is a third proportion and 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 proportion q1 is less than the second proportion q 2.

In some embodiments of the present application, when the first depth of discharge DODn is greater than a second ratio q2, and when the first depth of discharge DODn is 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 R3 n.

In some embodiments of the present application, the value of time point D0 is determined based on the response rate of the battery's concentration impedance.

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

In some embodiments of the present application, wherein the third ratio q3 is not equal to the fourth ratio q 4.

In some embodiments of the present application, wherein the first proportion q1 is equal to 10%, the second proportion q2 ranges from 70% to 80%.

In some embodiments of the present application, wherein the third proportion q3 ranges from 8% to 12%, and the fourth proportion q4 ranges from 2% to 5%.

In some embodiments of the present application, wherein the first depth of discharge DODn is smaller than the first proportion q1, the step of determining the first impedance Rn at the point in time Dn comprises: determining a first impedance Rn of the battery at a time point Dn 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.

In some embodiments of the present application, it further comprises determining a second aging parameter An of the battery at a point in time Dn based on the resulting second impedance R1n when the first depth of discharge DODn is equal to the first proportion q 1.

In some embodiments of the present application, it further comprises determining a second aging parameter An of the battery at a time point Dn based on the third impedance R2n obtained each time the third impedance R2n is obtained when the first depth of discharge DODn is greater than the first proportion q1 and less than or equal to the second proportion q 2.

In some embodiments of the present application, it further comprises determining a second aging parameter An of the battery at a time point Dn based on the fourth impedance R3n obtained each time the fourth impedance R3n is obtained when the first depth of discharge DODn is greater than the second proportion q 2.

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

In some embodiments of the present application, a relationship between a first voltage Vm of the battery at the second depth of discharge DODm and a 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, where the second depth of discharge DODm of the battery is equal to or greater than the first depth of discharge DODn, and m is 0,1,2,3.

In some embodiments of the present application, wherein DODm +1 differs from DODm by a fifth ratio q 5.

In some embodiments of the present application, wherein the fifth proportion q5 ranges from 3% to 8%.

In some embodiments of the present application, wherein said determining a relationship between a first voltage Vm of the battery at the second depth of discharge DODm and a discharged charge Qm of the battery at the second depth of discharge DODm further comprises: determining a temperature rise model of the battery based on the second resistance R1n, the third resistance R2n, or the fourth resistance R3 n.

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

In some embodiments of the present application, the 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 the maximum charge capacity Qmax of the battery.

In some embodiments of the present application, the discharged charge Q0 at the first depth of discharge DOD0 determines the full charge capacity FCC of the battery 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.

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.

According to an embodiment of the present application, an electronic device is provided, which includes: a processor; and a memory and a computer program stored on the memory and executable on the processor; the processor, the memory, and the computer program are configured to cause the electronic device to perform the steps of: acquiring a first voltage Vn, a first current In and a first temperature Tn of a battery at a time point Dn, wherein n is 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 acquired first voltage Vn, first current In and first temperature Tn; determining a first impedance Rn at a point in time Dn based on the first depth of discharge DODn determined at the point in time Dn.

According to an embodiment of the present application, a computer-readable storage medium is provided, on which a computer program is stored, which, when being executed by a processor, implements the method of any of the above embodiments.

The method for determining the impedance of the battery, the electronic device and the computer-readable storage medium provided by the embodiment of the application can timely and accurately update the impedance of the battery, and realize accurate prediction of the residual capacity of the battery.

Drawings

The drawings necessary for describing the embodiments of the present application or the prior art will be briefly described below in order to describe the embodiments of the present application. It is to be understood that the drawings in the following description are only some of the embodiments of the present application. It will be apparent to those skilled in the art that other embodiments of the drawings can be obtained from the structures illustrated in these drawings without the need for inventive work.

FIG. 1 is a schematic structural diagram of an electronic device according to an embodiment of the present application

FIG. 2 is a flow chart of a method for determining battery impedance according to an embodiment of the present application

FIG. 3 is a graph of battery depth of discharge versus battery operating voltage and open circuit voltage according to an embodiment of the present application

FIG. 4 is a graph of discharged charge of a battery, actual operating voltage of the battery, simulated operating voltage of the battery, and open-circuit voltage of the battery according to an embodiment of the present application

FIG. 5 is a flowchart of a method for obtaining a graph of discharged charge and simulated operating voltage of the battery shown in FIG. 4 according to an embodiment of the present application

FIG. 6 is a flowchart illustrating a method for determining a remaining charge of a battery according to an embodiment of the present application

FIG. 7 is a flowchart of a method for determining a full charge capacity of a battery according to an embodiment of the present application

FIG. 8 is a flowchart of a method for determining a state of charge of a battery according to an embodiment of the present application

FIG. 9 is a block diagram of a battery impedance determination apparatus according to an embodiment of the present application

FIG. 10 is a schematic diagram of a circuit of a battery impedance determination apparatus according to an embodiment of the present application

Detailed Description

Embodiments of the present application will be described in detail below. Throughout the specification, the same or similar components and components having the same or similar functions are denoted by like reference numerals. The embodiments described herein with respect to the figures are illustrative in nature, are diagrammatic in nature, and are used to provide a basic understanding of the present application. The examples of the present application should not be construed as limiting the present application.

As used herein, the terms "about", "substantially", are used to describe and illustrate minor variations. When used in conjunction with an event or circumstance, the terms can refer to instances where the event or circumstance occurs precisely as well as instances where the event or circumstance occurs in close proximity. For example, when used in conjunction with numerical values, the term can refer to a range of variation that is 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, two numerical values may be considered "substantially" the same if the difference between the two values is less than or equal to ± 10% of the mean of the values.

Moreover, for convenience in description, "first," "second," "third," etc. may be used herein to distinguish between different elements of a figure or series of figures. "first," "second," "third," etc. are not intended to describe corresponding components.

In this application, unless specified or limited otherwise, "disposed," "connected," "coupled," "secured," and words of similar import are used broadly and those skilled in the art will understand that the words used above apply to situations in which, for example, a fixed connection, a removable connection, or an integrated connection; it may also be a mechanical or electrical connection; it may also be directly connected or indirectly connected through intervening structures; or may be internal to both components.

Fig. 1 is a schematic structural diagram of an electronic device 100 according to an embodiment of the present application.

As shown in fig. 1, the electronic device 100 includes: memory 10, at least one processor 11, battery 12, analog-to-digital converter 13, and sensor 14. The above elements may be connected by a bus or directly. The battery impedance determination module 15 operates in the electronic device 100.

It should be noted that fig. 1 is only an example of the electronic device 100. In other embodiments, electronic device 100 may include more or fewer elements, or have a different configuration of elements. The electronic device 100 may be an electric motorcycle, an electric bicycle, an electric automobile, a mobile phone, a tablet computer, a digital assistant, a personal computer, or any other suitable rechargeable device.

The battery 12 is a rechargeable battery for supplying electric power 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, a lithium iron phosphate battery, or the like. 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 performed through the battery management system. The battery management system CAN be in communication connection with an energy storage inverter (PCS) through CAN or RS 485. The battery 12 includes a cell (not shown).

The analog-to-digital converter 13 is configured to measure a voltage and a current of the battery cell of the battery 12 during a charging, discharging, or standing process. In this embodiment, the analog-to-digital converter 13 includes a digital filter. The digital filter is used for filtering the voltage and current of the battery cell of the battery 12 in the charging, discharging or standing process. In one embodiment, the digital filter may be a first order low pass filter. The analog-to-digital converter 13 needs to process the acquired data, such as filtering. The analog-to-digital converter 13 cannot acquire data in the processing interval of the acquired data, which causes dead time of the analog-to-digital converter 13. The analog-to-digital converter 13 is a hardware circuit located in the entire apparatus 100. The analog-to-digital converter 13 can independently acquire, process and convert the required relevant data. The analog-to-digital converter 13 may be used in conjunction with the processor 11 to acquire, process and convert the desired associated data.

The sensor 14 is used to measure the temperature of the cells 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 pressure sensors, light sensors, gyroscopes, hygrometers, infrared sensors, etc.

The battery impedance determination module 15 may comprise a software module (software module) stored in, for example, the memory 10. The battery impedance determination module 15 may be executed by the processor 11.

In other embodiments, the battery impedance determination module 15 is a hardware circuit located throughout the apparatus 100 or a software module located in the processor 11. The battery impedance determination module 15 may be embodied using hardware circuitry. The battery impedance determination module 15 may independently embody the method of determining the battery impedance. The battery impedance determination module 15 may cooperate with the processor 11 to implement a method of determining battery impedance.

Fig. 2 is a flow chart of a method of determining battery impedance according to an embodiment of the present application. As shown in fig. 2, the method of determining the impedance of a battery may comprise the steps of:

in step S20, the relevant battery parameters are stored in the memory of the electronic device.

In this embodiment, the battery parameters may include: the corresponding relation between the battery open-circuit voltage OCV and the battery depth of discharge DOD, the battery temperature T and the battery aging parameter A is as follows: OCV ═ f (DOD, T, a); the corresponding relation between the battery discharge depth DOD and the battery open-circuit voltage OCV, the battery temperature T and the battery aging parameter A is as follows: DOD ═ g (OCV, T, a); the corresponding relation between the battery impedance R and the battery discharging depth DOD, the battery temperature T and the battery aging parameter A is as follows: r ═ h (DOD, T, a); pre-initial state of charge Pre _ SOC0 of the battery upon power up versus battery voltage and battery temperature: pre _ SOC0 is lookop (V, T). In other embodiments, the battery parameters may also include any desired correspondence and/or battery related parameters.

In this embodiment, the relevant battery parameters are stored in a memory of the electronic device. In other embodiments, the battery-related parameters may be stored in a memory of the electronic device and a random access memory of the electronic device.

In step S21, a first voltage Vn, a first current In and a first temperature Tn of the battery at a time point Dn are obtained.

In this embodiment, n is set to a non-negative integer equal to 0,1,2,3. Setting D0, D1, D2, D3.. Dn-1, Dn, Dn +1 as time points, wherein the time points Dn-1 and Dn may be different by a fixed value or a non-fixed value. The first voltage Vn represents an operating voltage of the battery at a time point Dn, the first current In represents an operating current of the battery at the time point Dn, and the first temperature Tn represents a 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.

The acquiring of the first voltage Vn, the first current In and the first temperature Tn of the battery at the time point Dn may be acquiring of the first voltage Vn and the first current In acquired at the time point Dn through an analog-to-digital converter, and acquiring of the first temperature Tn acquired at the time point Dn through a sensor. In other embodiments, the first voltage Vn, the first current In and the first temperature Tn at the time point Dn of the battery may be the first voltage Vn, the first current In and the first temperature Tn acquired by any suitable means at the time point Dn.

In step S22, a first depth of discharge DODn of the battery at the time point Dn is determined based on the acquired first voltage Vn, the first current In and the first temperature Tn.

The determining a first depth of discharge DODn of the battery at a point in time Dn comprises:

a1: an initial state of charge SOC0 of the battery at rest prior to charging and discharging is determined.

The determining the initial state of charge SOC0 of the battery at rest prior to charging and discharging includes:

a 1: the Pre-initial state of charge Pre _ SOC0 of the battery at the time of the power-on is determined from the first voltage Vn, the first current In, and the first temperature Tn of the battery at the time of the power-on.

In the present embodiment, the determining the Pre-initial state of charge Pre _ SOC0 of the battery at power-on based on the first voltage Vn, the first current In and the first temperature Tn of the battery at the time of the power-on includes: the Pre-initial state of charge Pre _ SOC0 that matches the first voltage Vn and the first temperature Tn at the time of the immediately preceding power-on is determined from the correspondence of the Pre-stored battery voltage and temperature with the Pre-initial state of charge Pre _ SOC 0.

In the present embodiment, the Pre-stored correspondence relationship between the voltage and temperature of the battery and the Pre-initial state of charge Pre _ SOC0 may be a relationship table Pre _ SOC0, which is lookeup (Vn, Tn), where Vn is the battery voltage immediately after power-on and Tn is the battery temperature immediately after power-on. In other embodiments, the Pre-stored battery voltage and temperature may be plotted versus the Pre-initial state of charge Pre _ SOC 0.

a 2: the effective open-circuit voltage Valid _ OCVn of the battery at the time point Dn is determined from the Pre-initial state of charge Pre _ SOC 0.

The determining of 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 certain period of time (specific values may be determined according to different models of the battery), an effective open-circuit voltage of the battery is determined according to the acquired first voltage Vn at the time point Dn, the first current In and the first temperature Tn through an open-circuit voltage method, that is, a formula Valid _ OCVn ═ Vn-inxr (Pre _ SOC0, Tn). Wherein Valid _ OCVn is an effective open-circuit voltage of the battery at the time point Dn, Vn is a first voltage of the battery at the time point Dn, In is a first current of the battery at the time point Dn, R (Pre _ SOC0, Tn) is a battery impedance, and R (Pre _ SOC0, Tn) is determined according to a Pre-stored Pre-initial state of charge Pre _ SOC0 and a corresponding relation table of temperature and battery impedance.

a 3: the initial state of charge SOC0 is determined from the effective open circuit voltage Valid _ OCVn.

The determining the initial state of charge SOC0 according to the effective open circuit voltage Valid _ OCVn includes: the initial state of charge SOC0 is determined from 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. The 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: and determining an initial state of charge SOC0 matched with the effective open-circuit voltage Valid _ OCV and the temperature at the time point Dn according to the corresponding relation between the prestored effective open-circuit voltage Valid _ OCV and the temperature of the battery and the initial state of charge SOC 0.

In the present embodiment, the correspondence relationship between the pre-stored effective open-circuit voltage Valid _ OCV and temperature of the battery and the initial state of charge SOC0 may be a LookUp table SOC0 (Valid _ OCVn, Tn). Wherein Valid _ OCVn is the effective open-circuit voltage of the battery at the time point Dn, and Tn is the first temperature Tn of the battery at the time point Dn. In other embodiments, the pre-stored effective open circuit voltage Valid _ OCV and the corresponding relationship between the temperature and the initial state of charge SOC0 of the battery may be a graph.

a 4: the above steps a2 and a3 are repeated to obtain the accurate initial state of charge SOC 0.

A2: the state of charge SOCn of the battery at the point in time Dn is determined.

Said determining the state of charge SOCn of the battery at the point in time Dn comprises: the state of charge SOCn of the cell at the point In time Dn is determined by coulomb integration method SOCn 0+ In x Δ t/Qmax. Where SOC0 is the initial state of charge determined In the foregoing steps a1 to a4, In is the first current at time point Dn, Δ t is the difference between Dn and D0, and Δ t is greater than 0, Qmax is the maximum capacity of the battery, which is a fixed value at the time of shipment of the battery.

A3: a first depth of discharge DODn at a point in time Dn is determined.

Said determining a first depth of discharge DODn at a point in time Dn comprises: after the determination of the state of charge SOCn of the battery at the point in time Dn, a first depth of discharge DODn at the point in time Dn is determined by the formula DODn-1-SOCn.

In step S23, a first impedance Rn at a time point Dn is determined based on the first depth of discharge DODn determined at the time point Dn.

Said determining a first impedance Rn at a point in time Dn based on the determined first depth of discharge DODn at the point in time Dn comprises: the first impedance Rn is determined according to the formula Rn (DODn, Tn, An) ═ OCV (DODn, Tn, An) -Vn)/In. Wherein DODn is a first depth of discharge of the battery at a point in time Dn; tn is a first temperature of the battery at time point Dn; an is An aging parameter of the battery at a time point Dn; in is a first current of the battery at a time point Dn; the OCV (DODn, Tn, An) is An open-circuit voltage of the battery at the time point Dn, and the OCV (DODn, Tn, An) is determined according to a correspondence relationship between the open-circuit voltage OCV of the battery and a depth of discharge DOD of the battery, a battery temperature, and a battery aging parameter. In this embodiment, the determining the first impedance Rn according to the formula Rn (DODn, Tn, An) ═ OCV (DODn, Tn, An) -Vn)/In includes:

b 1: the starting point of time D0 for the impedance calculation is determined.

The polarization effect exists at the moment when the battery is converted from the static state to the charge-discharge state or from the charge-discharge state to the static state. To minimize the effects of polarization effects, the starting time point D0 of the impedance calculation may be determined based on the response rate of the cell's concentration impedance.

As shown in fig. 3, fig. 3 is a graph of battery depth of discharge DODn, battery operating voltage Vn and open circuit voltage OCV according to an embodiment of the present application, with the abscissa representing battery depth of discharge DOD in percent and the ordinate representing voltage V in volts. Curve I is a curve of the open circuit voltage OCV of the battery as a function of the depth of discharge DOD of the battery, and curve II is a curve of the operating voltage Vn of the battery as a function of the depth of discharge DOD of the battery.

In the present embodiment, in order to prevent the disturbance effect caused by the instant loading, the starting time point D0 of the impedance calculation is selected to be about 600 seconds after the loading, that is, D0 is about 600 seconds. In other embodiments, the range of values for time point D0 is determined by the response rate of the concentration impedance for a particular cell, for example, about 500 seconds to about 800 seconds.

b 2: the value of the time interval Dn-Dn-1 for calculating the impedance Rn is determined.

In order to calculate the cell impedance Rn more accurately, the present embodiment sets the value of the time interval Dn-Dn-1 of the calculated impedance Rn in consideration of the ohmic impedance, the electrochemical impedance and the concentration impedance of the cell. In this embodiment, the time interval Dn-Dn-1 may have a value of about 60 seconds. In other embodiments, the value of the time interval Dn-Dn-1 may be set according to the ohmic impedance, the electrochemical impedance, and the concentration impedance of the cell, for example, about 100 seconds.

b 3: when the first depth of discharge DODn is smaller than the first ratio q1, a first impedance Rn at the point in time Dn is determined.

In the present embodiment, the first ratio q1 is 10%. In other embodiments, q may be set to any suitable value.

When the first depth of discharge DODn is smaller than the first ratio q1, determining the first impedance Rn at the time point Dn includes: every 60 seconds, the first impedance Rn is calculated according to the formula Rn (DODn, Tn, An) ═ OCV (DODn, Tn, An) -Vn)/In. Wherein DODn is a first depth of discharge of the battery at a point in time Dn; tn is a first temperature of the battery at time point Dn; a0 is a first aging parameter a0 of the battery, i.e. the aging parameter of the battery in the rest state, which can be considered to be a known value; in is a first current of the battery at a time point Dn; the OCV (DODn, Tn, a0) is an open-circuit voltage of the battery at the time point Dn, and the OCV (DODn, Tn, a0) is determined according to a correspondence relationship between the open-circuit voltage OCV of the battery and a depth of discharge DOD of the battery, a battery temperature T, and a battery aging parameter a.

b 4: when the first depth of discharge DODn is equal to the first proportion q1, a second impedance R1n and a second aging parameter An are determined.

When the first depth of discharge DODn is equal to the first proportion q1, the determining the second impedance R1n includes: a linear regression calculation is performed on the first impedance Rn obtained in the elapsed time period from the depth of discharge DOD0 to the depth of discharge DODn being equal to the first ratio q1 to obtain the second impedance R1 n. The linear regression equation is: y is w × x + b, where y is the second impedance R1n with DODn equal to the first ratio q1, x is the first ratio q1,

i and N are positive integers greater than or equal to 1.

When the first depth of discharge DODn is equal to the first proportion q1, the determining the second aging parameter An includes: a second aging parameter An of the battery at the point in time Dn is determined based on the resulting second impedance R1 n. The determining of the second aging parameter An of the battery at the time point Dn based on the obtained second impedance R1n comprises:

according to the corresponding relation between the pre-stored battery aging parameter A and the battery impedance R, determining a second aging parameter of the battery when the first depth of discharge DODn is equal to the first proportion q1

Wherein REOL (DODn, Tn) is the impedance of the battery when the battery capacity retention rate reaches 80% of the design capacity, is measured under laboratory conditions, is put in a memory as reference data, and can be determined according to the corresponding relation between the battery discharge depth and temperature pre-stored in the memory and the battery impedance; RNEW (DODn, Tn) is the impedance of the battery at the time of shipment, which is measured under laboratory conditions, placed in a memory as reference data, and can be determined according to the correspondence between the battery discharge depth and temperature, which are stored in the memory in advance, and the impedance of the battery; r1n (DODn, Tn) is the cell impedance at which the first depth of discharge DODn is equal to the first ratio q1, which is determined from the linear regression calculation described above.

Therefore, after determining the second aging parameter An of the battery at the time point Dn, the first impedance Rn +1 of the battery at the time point Dn +1 may be further determined based on the second aging parameter An. Therefore, the method for determining the battery impedance provided by the embodiment of the application can timely consider the aging parameters of the battery and the working temperature of the battery, so that the accuracy of determining the battery impedance is improved.

b 5: when the first depth of discharge DODn is greater than the first proportion q1 and less than or equal to the second proportion q2, the first impedance Rn at the point in time Dn is determined.

In the present embodiment, the first ratio q1 is smaller than the second ratio q2, and the second ratio q2 is 80%. In other embodiments, the second ratio q2 may be set to any suitable value, such as 70% to 80%.

The determining the first impedance Rn at the time point Dn when the first depth of discharge DODn is greater than the first proportion q1 and less than or equal to the second proportion q2 includes: every 60 seconds, the first impedance Rn is calculated according to the formula Rn (DODn, Tn, An) ═ OCV (DODn, Tn, An) -Vn)/In. Wherein DODn is a first depth of discharge of the battery at a point in time Dn; tn is a first temperature of the battery at time point Dn; in is a first current of the battery at a 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 is q1+ i × q3, where q3 is the third ratio and i is a positive integer, the battery aging parameter An is updated once based on the linearly calculated first impedance Rn, and thus An is the latest updated battery aging parameter, as described in detail below. The OCV (DODn, Tn, An) is An open-circuit voltage of the battery at the time point Dn, and is determined according to a correspondence relationship between the open-circuit voltage OCV of the battery and a depth of discharge DOD of the battery, a battery temperature T, and a battery aging parameter a.

In the present embodiment, the third ratio q3 is 10%. In other embodiments, the third ratio q3 may be set to any suitable value, for example, 8% to 12%.

b 6: when the first depth of discharge DODn is greater than the first proportion q1 and less than or equal to the second proportion q2, the third impedance R2n and the second aging parameter An are determined.

When the first depth of discharge DODn is greater than the first proportion q1 and less than or equal to the second proportion q2, the determining the third impedance R2n includes: when the first depth of discharge DODn is q1+ i × q3, a linear regression calculation is performed on all the first impedances Rn obtained during a period in which the depth of discharge increases from the third ratio q3 to the first depth of discharge DODn is q1+ i × q3 to obtain the third impedance R2 n. The linear regression equation is: y is w × x + b, where y is the third impedance R2n per increment of DODn by a third proportion q3, x is DODn per increment of q3,

i and N are positive integers greater than or equal to 1.

When the first depth of discharge DODn is greater than the first proportion q1 and less than or equal to the second proportion q2, the determining the third aging parameter a2 includes: a second aging parameter An of the battery at the point in time Dn is determined based on the resulting second impedance R2 n. The determining of the second aging parameter An of the battery at the time point Dn based on the obtained second impedance R2n comprises:

according to the pre-stored corresponding relation between the battery aging parameter A and the battery impedance R, when the first depth of discharge DODn is larger than a first proportion q1 and smaller than or equal to a second proportion q2, and when the first depth of discharge DODn is q1+ iSecond aging parameter at q3

Wherein REOL (DODn, Tn) is the impedance of the battery when the battery capacity retention rate reaches 80% of the design capacity, is measured under laboratory conditions, is put in a memory as reference data, and can be determined according to the corresponding relation between the battery discharge depth and temperature pre-stored in the memory and the battery impedance; RNEW (DODn, Tn) is the impedance of the battery at the time of shipment, which is measured under laboratory conditions, placed in a memory as reference data, and can be determined according to the correspondence between the battery discharge depth and temperature, which are stored in the memory in advance, and the impedance of the battery; r2n (DODn, Tn) is a cell impedance corresponding to the cell when the first depth of discharge DODn is greater than the first proportion q1 and less than or equal to the second proportion q2 and when the first depth of discharge DODn is q1+ i × q3, which is determined according to the above linear regression calculation.

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. Accordingly, when the first impedance Rn is calculated according to the formula Rn (DODn, Tn, An) ═ OCV (DODn, Tn, An) -Vn)/In every 60 seconds, it is possible to determine the battery impedance based on the aging parameter of the newly determined battery, that is, to determine the first impedance Rn +1 of the battery at the time point Dn +1 based on the second aging parameter An of the battery at the time point Dn, thereby improving the accuracy of the battery impedance determination.

b 7: when the first depth of discharge DODn is greater than the second ratio q2, a first impedance Rn at a point in time Dn is determined.

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: every 60 seconds, the first impedance Rn is calculated according to the formula Rn (DODn, Tn, An) ═ OCV (DODn, Tn, An) -Vn)/In. Wherein DODn is a first depth of discharge of the battery at a point in time Dn; tn is a first temperature of the battery at 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 proportion q1 and less than or equal to the second proportion q2, and when the first depth of discharge DODn is q2+ i × q4, where q4 is the fourth proportion, the battery aging parameter An is updated once based on the linearly calculated first impedance Rn, and thus An is the latest updated battery aging parameter, which is calculated as described In detail below. The OCV (DODn, Tn, An) is An open-circuit voltage of the battery at the time point Dn, and is determined according to a correspondence relationship between the open-circuit voltage OCV of the battery and a depth of discharge DOD of the battery, a battery temperature T, and a battery aging parameter a.

In the present embodiment, the fourth value is 3%. In other embodiments, the fourth value may be set to any suitable value, for example, 2% to 5%. Since the discharge end battery impedance changes greatly, to improve the accuracy of the calculation, the fourth value may be set according to the actual situation.

b 8: when the first depth of discharge DODn is greater than the second proportion q2, a fourth impedance R3n and a second aging parameter An are determined.

When the first depth of discharge DODn is greater than the second ratio q2, the determining a fourth impedance R3n includes: when the first depth of discharge DODn is q2+ i × q4, a linear regression calculation is performed on all the first impedances Rn obtained during a period in which the depth of discharge increases by a fourth value to obtain a fourth impedance R3 n. The linear regression equation is: y is w × x + b, where y is the fourth impedance R3n for each increment of the fourth value by DODn, x is the fourth impedance R3 for each increment of the fourth value by DODn,

i and N are positive integers greater than or equal to 1.

When the first depth of discharge DODn is greater than the second proportion q2, the determining the second aging parameter An includes: a second aging parameter An of the battery at the point in time Dn is determined based on the resulting fourth impedance R3 n. The determining of the second aging parameter An of the battery at the time point Dn based on the obtained fourth impedance R3n comprises:

according to a pre-stored relationship corresponding table of the battery aging parameter A and the battery impedance R, when the first depth of discharge DODn of the battery is larger than the second proportion q2, when the first depth of discharge DODn is q2+ iSecond aging parameter at q4

Wherein REOL (DODn, Tn) is the impedance of the battery when the battery capacity retention rate reaches 80% of the design capacity, is measured under laboratory conditions, is put in a memory as reference data, and can be determined according to the corresponding relation between the battery discharge depth and temperature pre-stored in the memory and the battery impedance; RNEW (DODn, Tn) is the impedance of the battery at the time of shipment, which is measured under laboratory conditions, placed in a memory as reference data, and can be determined according to the correspondence between the battery discharge depth and temperature, which are stored in the memory in advance, and the impedance of the battery; r3n (DODn, Tn) is the corresponding cell impedance of the cell when the first depth of discharge DODn is greater than the second ratio q2 and when the first depth of discharge DODn is q2+ i × q4, which is determined according to the linear regression calculation described above.

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. Accordingly, when the first impedance Rn is calculated according to the formula Rn (DODn, Tn, An) ═ OCV (DODn, Tn, An) -Vn)/In every 60 seconds, it is possible to update the impedance of the battery based on the newly determined aging parameter of the battery, that is, to determine the first impedance Rn +1 of the battery at the time point Dn +1 based on the second aging parameter An of the battery at the time point Dn, thereby improving the accuracy of the battery impedance determination.

Therefore, the embodiment of the application considers the influence of the battery aging factor and the temperature factor, can more accurately determine the impedances R0, R1, R2.. Rn of the battery at the time points D0, D1 and D2... Dn, and further obtains 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.

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 may be added to implement filtering and clipping. For example, the formula Rnew ═ a × rolld + (1-a) × Rnew is employed to achieve first-order low-pass filtering. Wherein a is a filtering factor, Rnew is an impedance value of the current moment, and Rold is an impedance value of the previous moment. For example, the formula | Rnew-rolll | <Δr is designed with robustness to achieve clipping. Where Δ R is the maximum allowable impedance change value.

Fig. 4 is a graph of discharged battery charge Q, actual battery operating voltage Vn, simulated battery operating voltage Vm, and open-circuit battery voltage OCV according to an embodiment of the present application. As shown in fig. 4, the abscissa represents the discharged charge Q of the battery in mAh, and the ordinate represents the voltage in volts (V). Curve I is a curve of the battery open-circuit voltage OCV varying with the battery discharged charge Q, curve II is a curve of the battery actual operating voltage Vn varying with the battery discharged charge Q, and curve III is a curve of the battery simulated operating voltage Vm varying with the battery discharged charge Q.

Fig. 5 is a flowchart of a method for obtaining a graph of the discharged charge Q of the battery and the simulated operating voltage Vm of the battery shown in fig. 4 according to an embodiment of the present application.

In conjunction with fig. 4 and 5, the method of obtaining the graph of the discharged charge Q of the battery and the simulated operating voltage Vm of the battery shown in fig. 4 may include the steps of:

in step S50, the first impedance Rn at the time point Dn is determined.

The determining of the first impedance Rn at the point in time Dn comprises: the first impedance Rn at the point in time Dn is determined based on the method of determining the battery impedance as shown in fig. 2.

In the present embodiment, when the discharged charge is equal to about 250mAh, the battery has a depth of discharge DOD0, where the corresponding discharged charge is labeled as Q0, and the time corresponding to the depth of discharge DOD0 is the starting time point D0 of the impedance calculation.

When the discharged charge Q is equal to 1000mAh, the battery has a depth of discharge DODn, where the corresponding discharged charge discharged from depth of discharge DOD0 to depth of discharge DODn is labeled Qn. In the time from the depth of discharge DOD0 to the depth of discharge DODn, the depth of discharge DODn at the time point Dn is determined by the electronic device shown In fig. 1 and the method of determining the impedance of the battery shown In fig. 2, 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 the first temperature Tn of the battery at the time point Dn and the first current In of the battery at the time point Dn are obtained by the electronic device shown In fig. 1.

In step S51, the simulation of the operating voltage Vm of the battery is started from the time corresponding to the depth of discharge DODn.

The sign DODm represents the depth of discharge of the battery in the simulation process, that is, the second depth of discharge DODm of the battery according to the embodiment of the present application, where m is 0,1,2,3, and m is a non-negative integer, and when m is equal to 0, DODm corresponds to the depth of discharge DODn corresponding to the start of the simulation. The second depth of discharge DODm of the battery is equal to or greater than the first depth of discharge DODn.

The simulation of the operating voltage of the battery from the time point corresponding to the depth of discharge DODn includes: the operating voltage simulation of the battery is started from when m is equal to 0. During the voltage simulation of the battery, the depth of discharge of the battery was increased at a rate of 5%. That is, DODm +1 differs from DODm by a fixed fifth ratio q 5. In the present embodiment, DODm +1 is DODm + 5%, that is, the fifth ratio q5 is 5%. In other embodiments, the fifth proportion q5 ranges from 3% to 8%.

In step S52, the first voltage Vm of the battery at the depth of discharge DODm is determined.

The determining the first voltage Vm of the battery at the depth of discharge DODm includes: according to ohm's law, the first voltage Vm at the depth of discharge DODm of the battery is determined as OCV (DODm, Tm, An) -In × Rn (DODm, Tm, An). Wherein OCV (DODm, Tm, An) is the open circuit voltage of the battery at depth of discharge DODm; an is a second aging parameter determined at the depth of discharge DODn of the battery, In is a first current obtained at the depth of discharge DODn of the battery, and Rn (DODm, Tm, An) is a battery aging parameter An determined at the depth of discharge DODn of the battery and a resistance taking into account the temperature Tm during the simulation. Tm is the battery temperature during the simulation.

To predict temperature changes during the simulation, a temperature rise model may be added:

wherein 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,

for the entropy coefficient, h is the battery heat dissipation coefficient, S is the surface area of the battery, Rnew is the second impedance R1n, the third impedance R2n or the fourth impedance R3n at the time point Dn determined according to the method of determining the battery impedance shown in fig. 2.

In step S53, the simulation is stopped when the first voltage Vm of the battery is equal to the cutoff voltage Vterm of the battery.

In the present embodiment, the cutoff voltage Vterm of the battery is a fixed value.

The open circuit voltage of the aged battery is smaller than the open circuit voltage of the battery immediately after shipment. If the aging factor is not considered, the battery open-circuit voltage value is larger, so that the determined initial discharge depth is larger, and the subsequent accuracy of battery impedance and battery capacity calculation is influenced. The battery impedance after aging is higher than the battery impedance immediately after shipment, and if the aging factor is not considered, the determined resistance at the time point Dn is small, which affects the accuracy of the subsequent capacity calculation.

Moreover, the open circuit voltage at 0 ℃ and the open circuit voltage at 25 ℃ may differ by 50mV for the same depth of discharge, and the calculation error of the depth of discharge increases by 0.5% regardless of the temperature variation. Also, temperature changes have a greater effect on the battery impedance. For example, at the same depth of discharge, the determined resistance at time point Dn of 0 ℃ may differ by 150m Ω from the determined resistance at time point Dn of 25 ℃, and the resistance calculation error at time point Dn may increase by 15% regardless of temperature variations.

Therefore, in the process of simulating the working voltage of the battery along with the discharged charge Q of the battery, the embodiment of the application can accurately predict the change of the working voltage of the simulated battery along with the discharged charge Q of the battery by considering the aging factor of the battery and the temperature change factor in the charging and discharging process of the battery so as to accurately display the electric quantity.

Fig. 6 is a flowchart of a method for determining a remaining charge of a battery according to an embodiment of the present application. As shown in fig. 6, the method of determining the remaining charge of the battery may include the steps of:

in step S60, the maximum depth of discharge DODmax is determined.

The determining the maximum depth of discharge DODmax includes: the simulation is stopped when the first voltage Vm of the battery is equal to the cut-off voltage Vterm of the battery, at which time the maximum depth of discharge doddmax is determined.

In step S61, the remaining charge Qres of the battery at the first depth of discharge DODn is determined based on the maximum depth of discharge DODmax.

The determining the remaining charge Qres of the battery at the first depth of discharge DODn based on the maximum depth of discharge DODmax includes: and determining the residual charge Qres | DODmax-DODn | × Qmax of the battery at the first depth of discharge DODn at the time of starting the simulation based on the determined maximum depth of discharge Dmax, the first depth of discharge DODn at the time of starting the simulation, and the maximum charge capacity Qmax of the battery, wherein the maximum charge capacity Qmax of the battery is a fixed value at the time of factory shipment of the battery.

The remaining charge Qres of the battery at the first depth of discharge DODm may also be determined. As shown in fig. 4, the remaining charge Qres ═ DODmax-DODm | × Qmax of the battery at the second depth of discharge DODm.

Fig. 7 is a flowchart of a method for determining the full battery charge capacity FCC according to an embodiment of the present application. As shown in fig. 7, the method of determining the full battery charge capacity FCC may include the steps of:

in step S70, the discharged charge Q0 at the first depth of discharge DOD0 determines the full charge capacity FCC of the battery, Q0+ Qn + Qres, based on the determined remaining charge Qres at the first depth of discharge DODn and the determined discharged charge Qn at the first depth of discharge DODn.

The full charge capacity FCC of the battery may also be determined as Q0+ Qm + Qres 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 DOD 0.

Fig. 8 is a flowchart of a method for determining a state of charge SOC of a battery according to an embodiment of the present application. As shown in fig. 8, the method of determining the state of charge SOC of a battery may comprise the steps of:

in step S80, the state of charge SOC of the battery is determined to be Qres/FCC based on the determined remaining charge Qres at the first depth of discharge DODn and the determined full charge capacity FCC of the battery.

Fig. 9 is a block diagram of a battery impedance determination apparatus according to an embodiment of the present application. In one embodiment, the battery impedance determination module 15 may be partitioned into one or more modules included in the memory 10. The battery impedance determination module 15 may comprise a software module (software module) stored in, for example, the memory 10. The battery impedance determination module 15 may be executed by the processor 11. In other embodiments, the battery impedance determination module 15 may be embodied using hardware circuitry. The battery impedance determination module 15 may independently embody the method of determining the battery impedance. The battery impedance determination module 15 may cooperate with the processor 11 to implement a method of determining battery impedance.

As shown in fig. 9, the battery impedance determination module 15 may be divided into an acquisition module 901, a depth of discharge determination module 902, a battery impedance determination module 903, and an aging parameter determination module 904. The obtaining module 901 may be configured to obtain a first voltage Vn, a first current In, and a first temperature Tn of the battery at a time point Dn. The depth of discharge determination module 902 may be configured to determine a first depth of discharge DODn of the battery at a time point Dn based on the obtained first voltage Vn, the first current In and the first temperature Tn. The battery impedance determination module 903 may be configured to determine a first impedance Rn at a point in time Dn based on the determined first depth of discharge DODn at the point in time Dn. The aging parameter determination module 904 may be configured to determine a second aging parameter An based on the determined first impedance Rn.

The battery impedance determining device of the embodiment can accurately and timely update the battery impedance. For details, reference may be made to the above-mentioned embodiments of the method for determining the impedance of the battery, and details will not be given here.

In this embodiment, the memory 10 may be an internal memory of the electronic device 100, that is, a memory built in the electronic device 100. In other embodiments, the memory 10 may also be an external memory of the electronic device 100, i.e., a memory externally connected to the electronic device 100. In some embodiments, the memory 100 is used for storing program code, various data and computer programs, for example a computer program storing a battery impedance determination module 15 installed in the electronic device 100, which is executable on the processor, and the processor, the memory and the computer program are configured to cause the electronic device 100 to implement the above-described method of determining battery impedance. The memory 10 may include random access memory and may also include non-volatile memory such as a hard disk, a memory, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), at least one magnetic disk storage device, a Flash memory device, or other volatile solid state storage device.

In an embodiment, the processor 11 may be a Central Processing Unit (CPU), other general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf Programmable Gate Array (FPGA) or other Programmable logic device, a discrete Gate or transistor logic device, a discrete hardware component, or the like. A general purpose processor may be a microprocessor or the processor may be any other conventional processor or the like.

The modules in the battery impedance determination module 15, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, all or part of the flow in the method of the embodiments described above can be realized by the present application, and the program can be stored in a computer-readable storage medium. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer readable medium may include: any entity or device capable of carrying the computer program code, recording medium, usb disk, removable hard disk, magnetic disk, optical disk, computer Memory, Read-Only Memory (ROM), Random Access Memory (RAM), electrical carrier wave signals, telecommunications signals, software distribution medium, and the like. It should be noted that the computer readable medium may contain content that is subject to appropriate increase or decrease as required by legislation and patent practice in jurisdictions, for example, in some jurisdictions, computer readable media does not include electrical carrier signals and telecommunications signals in accordance with legislation and patent practice.

It is understood that the above described division of modules is a logical division of functions, and that in actual implementation, there may be other divisions. In addition, functional modules in the embodiments of the present application may be integrated into the same processing unit, or each module may exist alone physically, or two or more modules are integrated into the same unit. The integrated module can be realized in a hardware mode, and can also be realized in a mode of hardware and a software functional module.

Fig. 10 is a schematic diagram of a circuit of a battery impedance determination apparatus according to an embodiment of the present application. As shown in fig. 10, the battery impedance determination apparatus circuit 200 includes: an acquisition circuit 201 and a parameter determination circuit 203.

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.

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

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

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

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

The circuit of the battery impedance determination device of the embodiment can accurately and timely update the battery impedance. For details, reference may be made to the above-mentioned embodiments of the method for determining the impedance of the battery, and details will not be given here. The battery impedance determination device circuit of the present embodiment may be implemented by a combination of conventional circuit elements (e.g., without limitation, filters, amplifiers, etc.), and will not be described in detail herein.

Claims

1. A method of determining battery impedance, comprising:

acquiring a first voltage Vn, a first current In and a first temperature Tn of the battery at a time point Dn, wherein n is 0,1,2,3, and n is a non-negative integer;

determining a first depth of discharge DODn of the battery at a point In time Dn based on the first voltage Vn, the first current In, and the first temperature Tn;

a first impedance Rn is determined based on the first depth of discharge DODn determined at the point in time Dn.

2. The method for determining battery impedance of claim 1 wherein a linear regression calculation is performed on the first impedance Rn to obtain a second impedance R1n when the first depth of discharge DODn is equal to a first ratio q 1.

3. The method of determining battery impedance of claim 2 wherein when the first depth of discharge DODn is greater than the first proportion q1 and less than or equal to a second proportion q2, and when the first depth of discharge DODn is q1+ i × q3, where q3 is a third proportion and i is 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 proportion q1 is less than the second proportion q 2.

4. The method of claim 3, wherein when the first depth of discharge DODn is greater than a second ratio q2, and when the first depth of discharge DODn is 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 R3 n.

5. The method for determining impedance of a battery as claimed in claim 1, wherein the value of time point D0 is determined according to a response rate of a concentration impedance of the battery.

6. The method of determining battery impedance of claim 5 wherein the value of time point D0 ranges from 500 seconds to 800 seconds.

7. The method of determining battery impedance of claim 4 wherein the third proportion q3 is not equal to the fourth proportion q 4.

8. The method of determining battery impedance of claim 3 wherein the first proportion q1 is 10% and the second proportion q2 ranges from 70% to 80%.

9. The method of determining battery impedance of claim 4 wherein the third proportion q3 ranges from 8% to 12% and the fourth proportion q4 ranges from 2% to 5%.

10. The method of determining battery impedance of claim 2 wherein, when the first depth of discharge DODn is less than the first proportion q1, the step of determining a first impedance Rn at a point in time Dn comprises: determining a first impedance Rn of the battery 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 resting state.

11. The method of determining battery impedance of claim 2 further comprising determining a second aging parameter An for the battery based on the resulting second impedance R1n when the first depth of discharge DODn is equal to the first proportion q 1.

12. The method of determining battery impedance of claim 3 further comprising determining a second aging parameter An of the battery based on the third impedance R2n derived whenever the third impedance R2n is derived when the first depth of discharge DODn is greater than the first proportion q1 and less than or equal to the second proportion q 2.

13. The method of determining battery impedance of claim 4 further comprising determining a second aging parameter An of the battery based on the fourth impedance R3n derived each time the fourth impedance R3n is derived when the first depth of discharge DODn is greater than the second ratio q2 f.

14. The method of determining battery impedance of any of claims 11-13, further comprising: determining a first impedance Rn +1 of the battery at a time point Dn +1 based on a second aging parameter An of the battery.

15. The method of determining battery impedance of any of claims 11-13, further comprising: determining a relationship between a first voltage Vm of the battery at the second depth of discharge DODm and a discharged charge Qm of the battery at the second depth of discharge DODm 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 is 0,1,2,3.

16. The method of determining battery impedance of claim 15 wherein DODm +1 differs from DODm by a fifth ratio q 5.

17. The method of determining battery impedance of claim 16 wherein said fifth proportion q5 ranges from 3% to 8%.

18. The method of determining battery impedance of claim 15 wherein said determining a relationship of a first voltage Vm of said battery at said second depth of discharge DODm to a discharged charge Qm of said battery at said second depth of discharge DODm further comprises: determining a temperature rise model of the battery based on the second resistance R1n, the third resistance R2n, or the fourth resistance R3 n.

19. The method of determining battery impedance of claim 15 further comprising determining a maximum depth of discharge doddmax when the first voltage Vm of the battery is equal to the cutoff voltage Vterm of the battery.

20. The method of determining battery impedance of claim 19, determining a remaining charge Qres of the battery at the second depth of discharge DODm based on the maximum depth of discharge DODmax, the second depth of discharge DODm, and a maximum charge capacity Qmax of the battery.

21. The method of determining battery impedance of claim 20 further comprising: the discharged charge Q0 at the first depth of discharge DOD0 determines the full charge capacity FCC of the battery based on the residual charge Qres at the second depth of discharge DODm, the discharged charge Qm at the second depth of discharge DODm.

22. The method of determining battery impedance of claim 21 further comprising: determining a state of charge, SOC, of the battery based on the determined remaining charge, Qres, at the second depth of discharge, DODm, and the determined full charge capacity, FCC, of the battery.

23. An electronic device, comprising:

a processor; and

a memory and a computer program stored on the memory and executable on the processor;

wherein the processor, the memory, and the computer program are configured to cause the electronic device to perform the steps of:

acquiring a first voltage Vn, a first current In and a first temperature Tn of a battery at a time point Dn, wherein n is 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 acquired first voltage Vn, first current In and first temperature Tn;

determining a first impedance Rn at a point in time Dn based on the first depth of discharge DODn determined at the point in time Dn.

24. The electronic device of claim 23, wherein when the first depth of discharge DODn is equal to a first ratio q1, a linear regression calculation is performed on the first impedance Rn to obtain a second impedance R1 n.

25. The electronic device of claim 24, wherein when the first depth of discharge DODn is greater than the first proportion q1 and less than or equal to a second proportion q2, and when the first depth of discharge DODn is q1+ i × q3, where q3 is a third proportion and 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 proportion q1 is less than the second proportion q 2.

26. The electronic device of claim 25, wherein when the first depth of discharge DODn is greater than a second ratio q2, and when the first depth of discharge DODn is 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 R3 n.

27. The electronic device of claim 23, wherein the value of time point D0 is determined from a response rate of a concentration impedance of the battery.

28. The electronic device of claim 27, wherein the value of time point D0 ranges from 500 seconds to 800 seconds.

29. The electronic device of claim 26, wherein the third ratio q3 is not equal to the fourth ratio q 4.

30. The electronic device of claim 25, wherein the first proportion q1 is equal to 10%, the second proportion q2 ranging from 70% to 80%.

31. The electronic device of claim 26, wherein the third proportion ranges from 8% to 12%, and the fourth proportion ranges from 2% to 5%.

32. The electronic device of claim 24, wherein when the first depth of discharge DODn is less than the first ratio q1, the step of determining a first impedance Rn at a point in time Dn comprises: determining a first impedance Rn of the battery at a time point Dn 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.

33. The electronic device of claim 24, further comprising determining a second aging parameter An of the battery at a point in time Dn based on the resulting second impedance R1n when the first depth of discharge DODn is equal to the first proportion q 1.

34. The electronic device of claim 25, further comprising determining a second aging parameter An of the battery at a point in time Dn based on the third impedance R2n obtained each time the third impedance R2n is obtained when the first depth of discharge DODn is greater than the first proportion q1 and less than or equal to the second proportion q2 f.

35. The electronic device of claim 26, further comprising determining a second aging parameter An of the battery at a point in time Dn based on the fourth impedance R3n obtained each time the fourth impedance R3n is obtained when the first depth of discharge DODn is greater than the second proportion q 2.

36. The electronic device of any one of claims 33-35, further comprising: determining a first impedance Rn +1 of the battery at a time point Dn +1 based on a second aging parameter An of the battery at the time point Dn.

37. The electronic device of any one of claims 33-35, further comprising: determining a relationship between a first voltage Vm of the battery at the second depth of discharge DODm and a discharged charge Qm of the battery at the second depth of discharge DODm 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 is 0,1,2,3.

38. The electronic device of claim 37 wherein DODm +1 differs from DODm by a fifth ratio q 5.

39. The electronic device of claim 38, wherein the fifth proportion q5 ranges from 3% to 8%.

40. The electronic device of claim 37, wherein said determining a relationship between a first voltage Vm of the battery at the second depth of discharge DODm and a discharged charge Qm of the battery at the second depth of discharge DODm further comprises: determining a temperature rise model of the battery based on the second resistance R1n, the third resistance R2n, or the fourth resistance R3 n.

41. The electronic device of claim 37, further comprising determining a maximum depth of discharge (DODmax) when a first voltage (Vm) of the battery is equal to a cutoff voltage (Vterm) of the battery.

42. The electronic device of claim 41, determining a remaining charge Qres of the battery at the second depth of discharge DODm based on the maximum depth of discharge DODmax, the second depth of discharge DODm, and a maximum charge capacity Qmax of the battery.

43. The electronic device of claim 42, further comprising: the discharged charge Q0 at the first depth of discharge DOD0 determines the full charge capacity FCC of the battery based on the determined residual charge Qres at the second depth of discharge DODm, the discharged charge Qm at the second depth of discharge DODm.

44. The electronic device of claim 43, further comprising: determining a state of charge, SOC, of the battery based on the determined remaining charge, Qres, at the second depth of discharge, DODm, and the determined full charge capacity, FCC, of the battery.

45. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the method of any one of claims 1-22.