A battery state of charge estimation method and device, vehicle and storage medium

Abstract

The application relates to a battery state of charge estimation method and device, a vehicle and a storage medium, and relates to the technical field of computers. The method comprises the following steps: acquiring a voltage value of a battery at a current time; and determining an offset angle corresponding to the voltage value at the current time according to the voltage value at the current time; wherein the offset angle corresponding to the voltage value at the current time is used to represent the relationship between the battery capacity corresponding to the voltage value at the current time and the voltage value at the current time in the voltage characteristic curve of the battery; and then the SOC value of the battery at the current time is determined according to a mapping relationship and the offset angle corresponding to the voltage value at the current time; wherein the mapping relationship is a one-to-one correspondence relationship between the offset angle and the SOC value, which is determined based on the voltage value and the actual battery capacity of the battery during the running process. Therefore, the mapping relationship between the offset angle and the SOC value can more accurately reflect the actual running condition of the battery, thereby improving the estimation accuracy of the SOC value of the battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the computer field, in particular to the new energy vehicle battery management technical field, and in particular to a battery state of charge estimation method and device, a vehicle and a storage medium. BACKGROUND

[0002] The battery state of charge (SOC) is an index reflecting the remaining capacity of the battery, and is used to represent the ratio of the remaining battery capacity to the capacity under the fully charged state. As one of the most important state parameters of the battery, the SOC is used in the battery management system (BMS) to control the charging current, the use power and the estimation of the remaining mileage, and is a basic parameter for ensuring the normal and safe use of the battery.

[0003] The battery SOC value estimation method in the related art mainly includes the ampere-hour integration method, the open circuit voltage method, the Kalman filter, the internal resistance method and the like. Among them, the Kalman filter method has a limited use scenario and cannot be applied to the battery with a voltage platform in the voltage characteristic curve, for example, the lithium iron phosphate battery. The internal resistance method needs to estimate the internal resistance, which is difficult to realize in hardware. The open circuit voltage in the open circuit voltage method needs to be placed for a long time, which is difficult for the BMS to realize. The ampere-hour integration method only considers the integration of the current with respect to time, or modifies the capacity in combination with the dynamic discharge curve, and the dynamic discharge curve is affected by factors such as temperature, current, aging state and use condition, resulting in inaccurate estimation of the battery SOC value. Therefore, how to improve the accuracy of the battery SOC value is a problem to be solved at present. SUMMARY

[0004] The present application provides a battery state of charge estimation method and device, a vehicle and a storage medium to at least solve the technical problem of inaccurate battery SOC value estimation in the related art. The technical solution of the present application is as follows:

[0005] According to a first aspect of the present application, a battery state of charge estimation method is provided, which comprises: obtaining a voltage value of the battery at a current time; determining an offset angle corresponding to the voltage value at the current time according to the voltage value at the current time; the offset angle corresponding to the voltage value at the current time is used to represent the relationship between the battery capacity corresponding to the voltage value at the current time and the voltage value at the current time in the voltage characteristic curve of the battery; determining the SOC value of the battery at the current time according to the mapping relationship and the offset angle corresponding to the voltage value at the current time; the mapping relationship is a one-to-one correspondence between the offset angle and the SOC value determined based on the voltage value and the actual battery capacity of the battery during the running process.

[0006] According to the above technical means, the offset angle contains the relationship between the voltage value at the current moment and the corresponding electric quantity in the voltage characteristic curve. Compared with directly determining the SOC value of the battery based on the voltage value in the related art, the SOC value is determined based on the offset angle in the present application, which considers multiple parameters of the battery, so that the SOC value is more accurate. Moreover, the mapping relationship between the offset angle and the SOC value of the battery can be determined based on the voltage value and the actual battery electric quantity of the battery in the running process, so that the influence of the aging condition and the use condition of the battery on the battery capacity in the use process is considered, the mapping relationship can more accurately reflect the actual running state of the battery, and the estimation accuracy of the SOC value is improved.

[0007] In a possible implementation, the offset angle corresponding to the voltage value at the current moment is determined according to the voltage value at the current moment, including: obtaining the temperature and the current of the battery at the current moment; determining the voltage characteristic curve of the battery at the current moment based on the temperature and the current at the current moment; and determining the offset angle corresponding to the voltage value at the current moment according to the voltage value at the current moment and the voltage characteristic curve.

[0008] According to the above technical means, the voltage characteristic curve of the battery at the current moment under the condition of the temperature and the current at the current moment is determined, and then the offset angle corresponding to the voltage value at the current moment is further determined, so that the influence of the temperature and the current of the battery at the current moment on the offset angle corresponding to the voltage value at the current moment is considered, and the accuracy of the offset angle is improved.

[0009] In another possible implementation, the offset angle corresponding to the voltage value at the current moment is determined according to the voltage value at the current moment, including: determining a reference line and a reference point of the voltage characteristic curve in a target coordinate system; the coordinate system in which the voltage characteristic curve is located includes a first axis and a second axis perpendicular to each other; the first axis is used to represent the voltage value of the battery; the second axis is used to represent the electric quantity of the battery; the reference line is parallel to the second axis, and the voltage value at the intersection of the reference line and the first axis is the cut-off voltage of the battery; the reference point is the mapping point of the value point of the battery in the full charge state or the fully discharged state in the voltage characteristic curve on the reference line; the radial line segment corresponding to the voltage value at the current moment is determined according to the voltage value at the current moment and the reference point; the radial line segment is the line segment between the value point at the voltage value at the current moment in the voltage characteristic curve and the reference point in the target coordinate system; the offset angle corresponding to the voltage value at the current moment is determined according to the radial line segment and the reference line; the offset angle is the angle of the included angle between the radial line segment and the reference line.

[0010] According to the above technical means, the voltage characteristic curve of the battery can be placed in the target coordinate system, and the reference line and the reference point can be determined, so that the radial line segment of the voltage value at the current time in the target coordinate system can be determined based on the position of the voltage value at the current time on the voltage characteristic curve, and the offset angle corresponding to the voltage value at the current time can be determined, so that the offset angle contains multiple parameter factors such as the voltage value at the current time of the battery and the corresponding power in the voltage characteristic curve, so that the SOC value can be more accurately determined based on the offset angle, and the accuracy of the SOC value is improved.

[0011] In another possible implementation, the reference line and the reference point of the voltage characteristic curve in the target coordinate system are determined, including: in the case that the voltage characteristic curve is a charging voltage characteristic curve, determining, in the target coordinate system, a straight line parallel to the second axis of the charging voltage characteristic curve of the battery as the reference line; and determining a mapping point of a value point of the battery in the charging voltage characteristic curve with an empty power value on the reference line as the reference point.

[0012] According to the above technical means, when the battery is in a charging state, the reference line and the reference point in the target coordinate system can be determined based on the charging voltage characteristic curve and the charging cutoff voltage of the battery, different working states of the battery are considered, and the reference line and the reference point can more accurately determine the offset angle, so as to improve the accuracy of the SOC value.

[0013] In another possible implementation, the reference line and the reference point of the voltage characteristic curve in the target coordinate system are determined, including: in the case that the voltage characteristic curve is a discharging voltage characteristic curve, determining, in the target coordinate system, a straight line parallel to the second axis of the discharging voltage characteristic curve of the battery as the reference line; and determining a mapping point of a value point of the battery in the discharging voltage characteristic curve with a full power value on the reference line as the reference point.

[0014] According to the above technical means, when the battery is in a discharging state, the reference line and the reference point in the target coordinate system can be determined based on the discharging voltage characteristic curve and the discharging cutoff voltage of the battery, different working states of the battery are considered, and the reference line and the reference point can more accurately determine the offset angle, so as to improve the accuracy of the SOC value.

[0015] In another possible implementation, the offset angle corresponding to the voltage value at the current time is determined according to the voltage value at the current time, including: obtaining a current value and a temperature of the battery at the current time; and based on the current value, the temperature, the voltage value at the current time, and a standard offset angle spectrum, the offset angle corresponding to the voltage value at the current time is found; the standard offset angle spectrum is used to indicate a mapping relationship between the current value, the temperature, the voltage value of the battery and the offset angle.

[0016] According to the technical means, the offset angle corresponding to the voltage value at the current moment can be directly searched based on the current value, the temperature and the standard offset angle spectrum, so that the rate of determining the offset angle is improved, and the SOC value of the battery can be determined faster.

[0017] In yet another possible implementation, the mapping relationship includes any one of the following: linear mapping, trigonometric function mapping, exponential function mapping, logarithmic function mapping, power function mapping, polynomial function mapping and Gaussian function mapping.

[0018] According to the technical means, the mapping relationship between the offset angle and the SOC value can be any one of the mapping relationships that realize one-to-one correspondence between the offset angle and the SOC value, so that the mapping relationship can not only be a simple linear mapping relationship, but also be a nonlinear mapping relationship. The linear mapping relationship cannot accurately reflect the nonlinear characteristics of the battery, and the nonlinear mapping relationship or a more complex function can be used to fit the actual operation of the battery, so that the mapping relationship can more accurately reflect the correspondence between the offset angle and the SOC value, and the estimation accuracy of the SOC value is improved.

[0019] In yet another possible implementation, the target coordinate system includes any one of the following: polar coordinate system, spherical coordinate system and cylindrical coordinate system.

[0020] According to the technical means, the SOC value of the battery can be determined in various coordinate systems, so that a suitable coordinate system can be selected according to the characteristics of the battery, so that the SOC value can be more accurately determined.

[0021] According to the second aspect of the present application, a battery state of charge estimation device is provided. The device includes an acquisition module and a determination module. The acquisition module is configured to acquire a voltage value of a battery at a current moment. The determination module is configured to determine an offset angle corresponding to the voltage value at the current moment according to the voltage value at the current moment. The offset angle corresponding to the voltage value at the current moment is used to represent a relationship between a battery capacity corresponding to the voltage value at the current moment and the voltage value at the current moment in a voltage characteristic curve of the battery. The determination module is further configured to determine an SOC value of the battery at the current moment according to a mapping relationship and the offset angle corresponding to the voltage value at the current moment. The mapping relationship is a one-to-one correspondence between the offset angle and the SOC value, which is determined based on the voltage value and the actual battery capacity of the battery during the operation process.

[0022] In a possible implementation, the determination module is specifically configured to acquire a temperature and a current of the battery at the current moment, determine a voltage characteristic curve of the battery at the current moment based on the temperature and the current at the current moment, and determine the offset angle corresponding to the voltage value at the current moment according to the voltage value at the current moment and the voltage characteristic curve.

[0023] In another possible implementation manner, the determining module is specifically configured to determine a reference line and a reference point of the voltage characteristic curve in the target coordinate system; the coordinate system in which the voltage characteristic curve is located comprises a first axis and a second axis perpendicular to each other; the first axis is used to represent a voltage value of the battery; the second axis is used to represent a power value of the battery; the reference line is parallel to the second axis, and a voltage value at an intersection of the reference line and the first axis is a cut-off voltage of the battery; the reference point is a mapping point of a value point of the battery in a full charge state or a fully discharged state on the reference line; the radial line segment corresponding to the voltage value at the current time is determined according to the voltage value at the current time and the reference point; the radial line segment is a line segment between the value point of the voltage characteristic curve at the current time and the reference point in the target coordinate system; and the offset angle corresponding to the voltage value at the current time is determined according to the radial line segment and the reference line; the offset angle is an angle of an included angle between the radial line segment and the reference line.

[0024] In another possible implementation manner, when the voltage characteristic curve is a charging voltage characteristic curve, the determining module is specifically configured to determine, in the target coordinate system, a straight line parallel to the second axis and passing through a charging cut-off voltage of the battery in the charging voltage characteristic curve as the reference line, and determine a mapping point of a value point of the battery in the charging voltage characteristic curve, in which the power value is null, on the reference line as the reference point.

[0025] In another possible implementation manner, when the voltage characteristic curve is a discharging voltage characteristic curve, the determining module is specifically configured to determine, in the target coordinate system, a straight line parallel to the second axis and passing through a discharging cut-off voltage of the battery in the discharging voltage characteristic curve as the reference line, and determine a mapping point of a value point of the battery in the discharging voltage characteristic curve, in which the power value is full, on the reference line as the reference point.

[0026] In another possible implementation manner, the determining module is specifically configured to acquire a current value and a temperature of the battery at the current time, and find the offset angle corresponding to the voltage value at the current time based on the current value, the temperature, the voltage value at the current time and a standard offset angle spectrum; the standard offset angle spectrum is used to indicate a mapping relationship between the current value, the temperature, the voltage value and the offset angle of the battery.

[0027] In another possible implementation manner, the mapping relationship comprises any one of the following: a linear mapping, a trigonometric function mapping, an exponential function mapping, a logarithmic function mapping, a power function mapping, a polynomial function mapping and a Gaussian function mapping.

[0028] In another possible implementation manner, the target coordinate system comprises any one of the following: a polar coordinate system, a spherical coordinate system and a cylindrical coordinate system.

[0029] According to a third aspect provided in the present application, a vehicle is provided, comprising: a processor; a memory for storing processor-executable instructions; wherein the processor is configured to execute the instructions to implement the method of the first aspect and any possible implementation thereof.

[0030] According to a fourth aspect provided in the present application, a computer-readable storage medium is provided, when instructions in the computer-readable storage medium are executed by a processor of a vehicle, the vehicle is enabled to perform the method of the first aspect and any possible implementation thereof.

[0031] According to a fifth aspect provided in the present application, a computer program product is provided, the computer program product comprises computer instructions, when the computer instructions are run on a vehicle, the vehicle performs the method of the first aspect and any possible implementation thereof.

[0032] Therefore, the above technical features of the present application have the following beneficial effects:

[0033] (1) The offset angle contains the relationship between the voltage value at the current moment and the corresponding electric quantity in the voltage characteristic curve. Compared with directly determining the SOC value of the battery based on the voltage value in the related art, the SOC value is determined based on the offset angle in the present application, which considers multiple parameters of the battery, so that the SOC value is more accurate. Moreover, the mapping relationship between the offset angle and the SOC value of the battery can be determined based on the voltage value and the actual battery electric quantity during the running process of the battery, so as to consider the influence of the aging condition, the use condition and the like of the battery during use on the battery capacity, so that the mapping relationship can more accurately reflect the actual running state of the battery, and the estimation accuracy of the SOC value is improved.

[0034] (2) According to the above technical means, by determining the voltage characteristic curve of the battery under the conditions of the temperature and the current at the current moment, the offset angle corresponding to the voltage value at the current moment is further determined, so as to consider the influence of the temperature and the current of the battery at the current moment on the offset angle corresponding to the voltage value at the current moment, and the accuracy of the offset angle is improved.

[0035] (3) The voltage characteristic curve of the battery can be placed in the target coordinate system, and the reference line and the reference point can be determined, so that the radial line segment of the voltage value at the current moment in the target coordinate system can be determined based on the position of the voltage value at the current moment on the voltage characteristic curve, and the offset angle corresponding to the voltage value at the current moment is determined, so that the offset angle contains multiple parameter factors such as the voltage value at the current moment of the battery and the corresponding electric quantity in the voltage characteristic curve, so that the SOC value can be more accurately determined based on the offset angle, and the accuracy of the SOC value is improved.

[0036] (4) When the battery is in a charging state, the reference line and the reference point in the target coordinate system can be determined based on the charging voltage characteristic curve and the charging cutoff voltage of the battery, different working states of the battery are considered, the offset angle can be more accurately determined by the reference line and the reference point, and the accuracy of the SOC value is improved.

[0037] (5) When the battery is in a discharging state, the reference line and the reference point in the target coordinate system can be determined based on the discharging voltage characteristic curve and the discharging cutoff voltage of the battery, different working states of the battery are considered, the offset angle can be more accurately determined by the reference line and the reference point, and the accuracy of the SOC value is improved.

[0038] (6) The offset angle corresponding to the voltage value at the current time can also be directly found based on the current value, the temperature and the standard offset angle spectrum, so that the rate of determining the offset angle is improved, and the SOC value of the battery can be determined faster.

[0039] (7) The mapping relationship between the offset angle and the SOC value can be any kind of mapping relationship that realizes one-to-one correspondence between the offset angle and the SOC value, so that the mapping relationship can not only be a simple linear mapping relationship, but also be a nonlinear mapping relationship, avoiding the case that the linear mapping relationship cannot accurately reflect the nonlinear characteristics of the battery. The actual running condition of the battery can be fitted by using a nonlinear mapping relationship or a more complex function, so that the mapping relationship can more accurately reflect the corresponding relationship between the offset angle and the SOC value, thereby improving the estimation accuracy of the SOC value.

[0040] (8) The SOC value of the battery can be determined in a plurality of coordinate systems, so that a suitable coordinate system can be selected according to the battery characteristics, so that the SOC value can be more accurately determined.

[0041] It should be noted that the technical effects brought by any one of the implementation manners of the second aspect to the fifth aspect can be referred to the technical effects brought by the corresponding implementation manners in the first aspect, which will not be repeated here.

[0042] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0043] The drawings incorporated into the specification and constituting a part of the specification, show embodiments consistent with the present application, and together with the specification, serve to explain the principles of the present application, and do not constitute an improper limitation on the present application.

[0044] Figure 1 is a flowchart of a battery state of charge estimation method according to an exemplary embodiment;

[0045] Figure 2 is a mapping relationship diagram between a radial line segment, a voltage value and an SOC value of a battery during discharging according to an example embodiment;

[0046] Figure 3 is a flowchart of another battery state of charge estimation method according to an example embodiment;

[0047] Figure 4 is a flowchart of yet another battery state of charge estimation method according to an example embodiment;

[0048] Figure 5 is a discharging voltage characteristic curve diagram according to an example embodiment;

[0049] Figure 6 is another discharging voltage characteristic curve diagram according to an example embodiment;

[0050] Figure 7 is a mapping relationship diagram between an offset angle, a radial line segment and a voltage value of a battery during discharging according to an example embodiment;

[0051] Figure 8 is a flowchart of yet another battery state of charge estimation method according to an example embodiment;

[0052] Figure 9 is a flowchart of yet another battery state of charge estimation method according to an example embodiment;

[0053] Figure 10 is a charging voltage characteristic curve diagram according to an example embodiment;

[0054] Figure 11 is a flowchart of yet another battery state of charge estimation method according to an example embodiment;

[0055] Figure 12 is another discharging voltage characteristic curve diagram according to an example embodiment;

[0056] Figure 13 is a flowchart of yet another battery state of charge estimation method according to an example embodiment;

[0057] Figure 14 is a block diagram of a battery state of charge estimation device according to an example embodiment;

[0058] Figure 15 is a block diagram of a vehicle according to an example embodiment. DETAILED DESCRIPTION

[0059] In order for the ordinary person skilled in the art to better understand the technical solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings.

[0060] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Rather, they are merely examples of devices and methods consistent with some aspects of the present application, as detailed in the appended claims.

[0061] The SOC value of the battery is one of the most important state parameters of the battery, which can be used in the BMS to control the charging current, the use of power, and the estimation of the remaining mileage, etc. This parameter is a basic parameter to ensure the normal and safe use of the battery. Among them, SOC can be defined using the stoichiometric ratio of the positive and negative electrodes of the battery, or based on the proportion of the remaining available lithium ions in the battery. In the BMS calculation, the SOC value includes the real SOC value used for control inside the software and the SOC value displayed on the controller area network (CAN) after a certain mapping relationship.

[0062] The real SOC value is the ratio of the actual remaining available capacity inside the battery to the nominal capacity of the battery, and the real SOC value is affected by the temperature, aging state and use conditions of the battery. At present, there are many methods to determine the real SOC value, such as: coulomb method based on its definition, open circuit voltage (OCV)-SOC curve table lookup method, and filtering method based on battery performance parameters such as internal resistance, voltage, etc. and combined with equivalent circuit model.

[0063] In the related art, a lithium ion battery SOC estimation method based on SOC-OCV optimization curve with patent number CN111722118B obtains the SOC value through OCV lookup table. This method obtains the discharge OCV curve under different temperature conditions through small current discharge, hybrid pulse power characteristic (HPPC) test and other means, and uses the curve to expand the Kalman filter algorithm to improve the calculation accuracy of the SOC value. The SOC estimation method of the battery state of charge with patent number CN106501726B determines the SOC value of the battery based on ampere-hour integration and OCV lookup table combination. According to the voltage characteristics of the OCV-SOC curve, the SOC interval is divided into voltage platform area, high voltage area and low voltage area. In the platform area, the SOC is calculated by using the ampere-hour integration method, and in the high and low voltage areas, the SOC is calculated by using the combination method of OCV lookup table and ampere-hour integration. However, in these two methods, for the battery system with a very wide platform interval in the voltage characteristic curve, the Kalman filter algorithm cannot converge, thereby causing the SOC value to deviate from the true value. Moreover, for the voltage platform area, if only the ampere-hour integration algorithm is used, the inherent error of the current sensor will be accumulated, and when the battery is not fully charged for a long time, there is a large error in the SOC value. Therefore, how to improve the accuracy of the battery SOC value is a problem to be solved at present.

[0064] To solve the above problems, the present application provides a battery state of charge estimation and determination method. The offset angle includes the relationship between the voltage value at the current time and the corresponding electric quantity in the voltage characteristic curve. Compared with the related art of directly determining the SOC value of the battery based on the voltage value, the SOC value determined based on the offset angle in the present application considers multiple parameters of the battery, making the SOC value more accurate. Moreover, the mapping relationship between the offset angle and the SOC value of the battery can be determined based on the voltage value and the actual battery capacity during the operation of the battery, thereby considering the influence of the aging condition, the use condition and the like of the battery on the battery capacity during the use of the battery, so that the mapping relationship can more accurately reflect the actual running state of the battery, and the estimation accuracy of the SOC value is improved.

[0065] To facilitate understanding, the battery state of charge estimation method provided by the present application is specifically introduced below in combination with the drawings.

[0066] Figure 1 is a flow chart of a battery state of charge estimation method according to an exemplary embodiment, as Figure 1 shown, the battery state of charge estimation method comprises the following steps:

[0067] S101, obtaining the voltage value of the battery at the current time.

[0068] As a possible implementation, when the battery is in the working state, the estimating device can obtain the voltage value of the battery at the current time in real time, so that the estimating device can determine the SOC value at the current time according to the voltage value at the current time.

[0069] For example, the estimating device can detect the voltage value of the battery in real time through the data acquisition module in the BMS, so as to obtain the voltage value of the battery at the current time. Wherein, the estimating device can also obtain the voltage value at the current time through a voltmeter, a multimeter, a battery meter or any other means that can be used to measure the voltage value of the battery during charging or discharging. The above-mentioned through the data acquisition module in the BMS is only an example, and the embodiments of the present application are not limited thereto.

[0070] It can be understood that when the estimating device obtains the voltage value of the battery at the current time using a voltmeter, a multimeter, a battery meter or the like, the voltmeter, the multimeter, the battery meter or the like should meet the accuracy requirement of the voltage value at the current time of the present application, so as to ensure the accuracy of the voltage value at the current time. In addition, the voltmeter, the multimeter, the battery meter or the like should be adapted to the working state of the battery, so as to avoid short circuit, electric shock or other accidents during the process of obtaining the voltage value at the current time, which may cause device damage or large error of the voltage value at the current time.

[0071] S102, according to the voltage value at the current time, determine the offset angle corresponding to the voltage value at the current time.

[0072] Wherein, the offset angle corresponding to the voltage value at the current time is used to represent the relationship between the battery capacity corresponding to the voltage value at the current time and the voltage value at the current time in the voltage characteristic curve of the battery.

[0073] As a possible implementation, after the estimating device obtains the voltage value of the battery at the current time, the estimating device can determine the offset angle corresponding to the voltage value at the current time in the voltage characteristic curve corresponding to the current working state of the battery according to the voltage value at the current time, so as to determine the SOC value based on the offset angle.

[0074] For example, the estimating device can place the voltage characteristic curve of the battery in a target coordinate system, and determine the reference line and the reference point of the target coordinate system based on the cut-off voltage of the battery, the full charge state or the fully discharged state of the battery. Thus, the estimating device can determine the value point corresponding to the voltage value at the current time in the voltage characteristic curve of the battery, and determine the offset angle corresponding to the voltage value at the current time according to the reference line and the reference point.

[0075] It can be understood that the target coordinate system includes any one of the following: a polar coordinate system, a spherical coordinate system, and a cylindrical coordinate system. The relevant management personnel can select based on the characteristics of the battery, so that the target coordinate system can more accurately reflect the relationship between the voltage value and the offset angle at the current time, and the embodiments of the present application do not limit this.

[0076] S103, determining the SOC value of the battery at the current time according to the offset angle corresponding to the voltage value at the current time and the mapping relationship.

[0077] The mapping relationship is a one-to-one correspondence between the offset angle and the SOC value determined based on the voltage value and the actual battery capacity of the battery during operation.

[0078] As a possible implementation manner, after determining the offset angle corresponding to the voltage value at the current time, the estimating device can also determine the SOC value of the battery at the current time according to the mapping relationship between the offset angle and the SOC value.

[0079] For example, the estimating device can perform calibration testing on the battery in advance, monitor the offset angle of the battery in the working state in real time when the battery is in different use conditions and aging states, and determine the SOC value corresponding to each time of the battery, so as to calibrate and fit the mapping relationship between the offset angle and the SOC value, determine the mapping relationship, and thus can determine the SOC value of the battery at the current time based on the offset angle and the mapping relationship after determining the offset angle corresponding to the voltage value at the current time. The mapping relationship includes any one of the following: linear mapping, trigonometric function mapping, exponential function mapping, logarithmic function mapping, power function mapping, polynomial function mapping, and Gaussian function mapping, and the embodiments of the present application do not limit this. The relevant management personnel can select a suitable mapping relationship based on the characteristics, state and actual demand of the battery to fit the actual running state of the battery, so as to more accurately reflect the correspondence between the offset angle and the SOC value, and improve the estimation accuracy of the SOC value.

[0080] Specifically, when the mapping relationship between the offset angle and the SOC value is a simple linear mapping, the estimating device can represent the mapping relationship between the offset angle and the SOC value based on the following expression when the battery is in a charging state:

[0081]

[0082] SOC i represents the SOC value of the battery at the current time, θ i represents the offset angle corresponding to the voltage value at the current time, and the value range of the offset angle is

[0083] When the battery is in the discharging state, the estimating device can represent the mapping relationship between the offset angle and the SOC value based on the following expression:

[0084]

[0085] wherein SOC i represents the SOC value of the battery at the current time, and θ i represents the offset angle corresponding to the voltage value at the current time, the value range of the offset angle is

[0086] When the mapping relationship between the offset angle and the SOC value is a trigonometric function mapping, when the battery is in the charging state, the estimating device can represent the mapping relationship between the offset angle and the SOC value based on the following expression:

[0087] SOC i = (1 + sin(θ i ))*100%;

[0088] wherein SOC i represents the SOC value of the battery at the current time, and θ i represents the offset angle corresponding to the voltage value at the current time, the value range of the offset angle is

[0089] When the battery is in the discharging state, the estimating device can represent the mapping relationship between the offset angle and the SOC value based on the following expression:

[0090] SOC i = sin(θ i )*100%;

[0091] wherein SOC i represents the SOC value of the battery at the current time, and θ i represents the offset angle corresponding to the voltage value at the current time, the value range of the offset angle is

[0092] It can be understood that according to the above expression, the battery state of charge estimation method of the application does not need the current of the battery as input when determining the SOC value, so the accuracy of the current sensor does not affect the accuracy of the SOC value.

[0093] As an example, Figure 2 is a mapping relationship diagram between the radial line segment, the voltage value and the SOC value of a battery in discharging according to an exemplary embodiment, which represents the corresponding relationship between the radial line segment, the voltage value and the SOC value of a battery in discharging in a three-dimensional Cartesian coordinate system, as shown in Figure 2As shown, the coordinate system includes three mutually perpendicular coordinate axes, wherein the SOC coordinate axis is used to represent the SOC value, the unit is %, and the value range is 0%-100%; the r coordinate axis is used to represent the radial line segment, and the value range is 0.8-1.2; and the Voltage coordinate axis is used to represent the discharge voltage value of the battery, that is, the voltage value at the current moment, the unit is V, and the value range is 2.5V-3.5V. The mapping relationship between the radial line segment, the voltage value and the SOC value is shown as a curve in Figure 2 .

[0094] In some embodiments, the estimation device can establish a target coordinate system based on the voltage characteristic curve of the battery, and determine the position of the voltage value at the current moment in the target coordinate system, so as to determine the offset angle corresponding to the voltage value at the current moment. Alternatively, the estimation device can also directly query the offset angle corresponding to the voltage value at the current moment in the standard offset angle spectrum based on the voltage value at the current moment. Therefore, the above step S102 specifically includes the following two possible implementation manners.

[0095] In one possible implementation manner, the estimation device can determine the voltage characteristic curve of the battery under the condition of the temperature and the current at the current moment, and further determine the offset angle corresponding to the voltage value at the current moment based on the voltage characteristic curve and the voltage value at the current moment. Therefore, as shown in Figure 3 , the above step S102 can be specifically implemented as steps S301-S303:

[0096] S301, obtaining the temperature and the current of the battery at the current moment.

[0097] As one possible implementation manner, the estimation device can also obtain the current value and the temperature of the battery at the current moment, so as to determine the voltage characteristic curve of the battery at the current moment based on the current value and the temperature of the battery at the current moment.

[0098] For example, the estimation device can obtain the current value and the temperature of the battery at the current moment through any one of a current sensor, a temperature sensor, a data acquisition module in the BMS or a third-party monitoring device, and the present application embodiment does not limit this.

[0099] S302, determining the voltage characteristic curve of the battery at the current moment based on the temperature and the current at the current moment.

[0100] As one possible implementation manner, after obtaining the temperature and the current of the battery at the current moment, the estimation device can also determine the voltage characteristic curve of the battery at the current moment under the condition of the temperature and the current at the current moment based on the temperature and the current of the battery at the current moment, so as to determine the offset angle corresponding to the voltage value at the current moment based on the voltage characteristic curve.

[0101] For example, the estimation device can perform multiple charging and discharging tests on the battery under multiple different temperature conditions and multiple different current conditions, obtain voltage characteristic curves of the battery under the multiple different temperature conditions and the multiple different current conditions, and perform fitting processing on the voltage values under the multiple different temperature conditions and the capacity values of the battery to determine the voltage characteristic curves of the battery under the different temperature conditions, and perform fitting processing on the voltage values under the multiple different current conditions and the capacity values of the battery to determine the voltage characteristic curves of the battery under the different current conditions. Thus, the estimation device can query the voltage characteristic curve of the battery at the current time based on the temperature and the current of the battery at the current time. The fitting processing is any method of performing fitting processing on multiple data in the related art, and embodiments of the present application do not limit the fitting processing.

[0102] S303, determining the offset angle corresponding to the voltage value at the current time according to the voltage value at the current time and the voltage characteristic curve.

[0103] As a possible implementation, after the estimation device determines the voltage characteristic curve of the battery at the current time, the estimation device can determine the offset angle corresponding to the voltage value at the current time according to the voltage value at the current time and the voltage characteristic curve.

[0104] For example, the estimation device can perform coordinate system conversion on the voltage characteristic curve to determine the reference line and the reference point of the voltage characteristic curve in the target coordinate system, and determine the radial line segment corresponding to the voltage value at the current time according to the voltage value at the current time and the reference point, so as to determine the offset angle corresponding to the voltage value at the current time according to the radial line segment and the reference line.

[0105] In a possible implementation, the estimation device can determine the reference line and the reference point of the voltage characteristic curve in the target coordinate system, and determine the radial line segment based on the position of the reference point and the voltage value at the current time in the target coordinate system, so as to determine the offset angle corresponding to the voltage value at the current time based on the radial line segment and the reference line. Thus, as shown in FIG. 4, the above step S303 can be implemented as steps S401-S403. Figure 4

[0106] S401, determining the reference line and the reference point of the voltage characteristic curve in the target coordinate system.

[0107] The coordinate system in which the voltage characteristic curve is located includes a first axis and a second axis perpendicular to each other, the first axis is used to represent the voltage value of the battery, and the second axis is used to represent the capacity of the battery. The reference line is parallel to the second axis, and the voltage value at the intersection of the reference line and the first axis is the cut-off voltage of the battery. The reference point is the mapping point of the value point of the battery in the full charge state or the fully discharged state on the reference line in the voltage characteristic curve.

[0108] ​As a possible implementation, the estimating device can obtain a voltage characteristic curve corresponding to the working state of the battery at the current time, and determine the reference line and the reference point based on the voltage characteristic curve, and establish the target coordinate system.

[0109] For example, the estimating device can take a straight line parallel to the second axis of the coordinate system in which the voltage characteristic curve is located as the reference line of the voltage characteristic curve in the target coordinate system, and determine that the battery is in a full charge state or a completely discharged state at the initial time of the working state based on the working state of the battery at the current time, determine the reference point based on the value point of the voltage characteristic curve of the battery in the full charge state or the completely discharged state on the reference line, and establish the target coordinate system based on the reference line, the reference point, and the voltage characteristic curve of the battery. The target coordinate system includes any one of the following: a polar coordinate system, a spherical coordinate system, and a cylindrical coordinate system. The cut-off voltage of the battery includes a charge cut-off voltage and a discharge cut-off voltage.

[0110] Specifically, Figure 5 is a discharge voltage characteristic curve diagram according to an example embodiment, which represents the corresponding relationship between the voltage value and the battery capacity of the discharge voltage characteristic curve of a lithium iron phosphate battery (LFP) in a traditional rectangular coordinate system. As shown in Figure 5 , the ordinate of the coordinate system represents Voltage, i.e. the discharge voltage of the battery, with a unit of V and a value range of 0V-3.6V; the abscissa of the coordinate system represents Q, i.e. the current in the battery, which can be used to represent the capacity of the battery, with a unit of Ah and a value range of 0Ah-120Ah. The corresponding relationship between the voltage value and the capacity of the LEP battery in the rectangular coordinate system is shown by the curve in Figure 5 .

[0111] Figure 6 is another discharge voltage characteristic curve diagram according to an example embodiment, Figure 6 taking the polar coordinate system as the target coordinate system, the offset angle as the polar angle, the radial line segment as the polar radius, the reference as the polar axis, and the reference point as the polar point to represent Figure 5 the corresponding relationship between the discharge voltage characteristic curve of the LEP battery in the polar coordinate system and the polar angle and the polar radius. As shown in Figure 6 , the polar axis is the discharge cut-off voltage V cut-off of the battery, which is parallel to the second axis of the coordinate system in which the voltage characteristic curve is located. Figure 5A straight line parallel to the middle horizontal coordinate axis, with a pole point SOC=100%, i.e. the projection point of the value point on the pole axis corresponding to the discharging voltage curve when the battery is in a full charge state, a pole radius r representing the line segment between any value point on the discharging voltage curve and the pole point, and a pole angle θ representing the included angle between the pole radius r and the pole axis. The corresponding relationship between the pole angle and the pole radius of the LEP battery in the polar coordinate system is shown by the curve in FIG. 1. Figure 6

[0112] S402, determining a radial line segment corresponding to the voltage value at the current moment according to the voltage value at the current moment and the reference point.

[0113] The radial line segment is a line segment between the value point at the voltage value at the current moment on the voltage characteristic curve and the reference point in the target coordinate system.

[0114] As a possible implementation manner, after determining the reference line and the reference point of the voltage characteristic curve in the target coordinate system, the estimation device can determine the radial line segment corresponding to the voltage value at the current moment based on the voltage value at the current moment and the reference point.

[0115] For example, the estimation device can determine the position of the voltage value at the current moment in the voltage characteristic curve in the traditional coordinate system based on the voltage value at the current moment, thereby determining the corresponding position of the voltage value at the current moment on the voltage characteristic curve in the target coordinate system, and determining the line segment between the two points as the radial line segment based on the corresponding position of the voltage value at the current moment in the target coordinate system and the reference point.

[0116] S403, determining an offset angle corresponding to the voltage value at the current moment according to the radial line segment and the reference line.

[0117] The offset angle is the angle of the included angle between the radial line segment and the reference line.

[0118] As a possible implementation manner, after determining the radial line segment corresponding to the voltage value at the current moment, the estimation device can determine the angle of the included angle between the radial line segment and the reference line at the reference point as the offset angle according to the radial line segment and the reference line of the target coordinate system.

[0119] Specifically, the estimation device can determine the offset angle corresponding to the voltage value at the current moment based on the following expression:

[0120]

[0121]

[0122] wherein θ i represents the offset angle corresponding to the voltage value at the current moment, V i represents the voltage value at the current moment, and V​cut-off Indicates the battery's cutoff voltage, r i This represents the radial line segment corresponding to the voltage value at the current moment.

[0123] As an example, Figure 7 This is a schematic diagram illustrating the mapping relationship between the offset angle, radial segment, and voltage value of a battery during discharge, according to an exemplary embodiment. It shows the correspondence between the offset angle, radial segment, and voltage value of a battery during discharge in a three-dimensional Cartesian coordinate system. Figure 7 As shown, this coordinate system includes three mutually perpendicular coordinate axes. The θ axis represents the offset angle, with units of π and a range of 0π-0.5π. The Voltage axis represents the battery's discharge voltage, i.e., the current voltage value, with units of V and a range of 2.6V-3.8V. The r axis represents the meridional line segment, with a range of 0.4-1.2. The mapping relationship between the offset angle, the radial line segment, and the voltage value is as follows: Figure 7 The curve in the figure is shown.

[0124] In another possible implementation, the estimation device can also acquire the battery's current and temperature at the current moment, and then look up the offset angle corresponding to the current voltage value in a standard offset angle spectrum based on the current value, temperature, and current voltage value. Therefore, as... Figure 8 As shown, the above step S102 can be specifically implemented as the following steps S801-S802:

[0125] S801: Obtain the current value and temperature of the battery at the current moment.

[0126] As one possible implementation, the estimation device can also obtain the battery's current value and temperature at the current moment, so that it can look up the offset angle corresponding to the voltage value at the current moment in the standard offset angle spectrum based on the current value and temperature.

[0127] For example, the estimation device can obtain the current value and temperature of the battery at the current moment through any of the following methods: current sensor, temperature sensor, data acquisition module in BMS, or third-party monitoring equipment. This application embodiment does not limit this.

[0128] S802. Based on the current value, temperature, current voltage value, and standard offset angle spectrum, find the offset angle corresponding to the current voltage value.

[0129] The standard offset angle spectrum is used to indicate the mapping relationship between the battery's current, temperature, voltage and offset angle.

[0130] As a possible implementation, after obtaining the current value of the current and the temperature of the battery at the current time, the estimation device can search for a standard offset angle spectrum corresponding to the current value and the temperature based on the current value and the temperature, and then search for the offset angle corresponding to the voltage value at the current time in the standard offset angle spectrum.

[0131] It can be understood that the standard offset angle spectrum is established as follows: the estimation device performs a large number of charging and discharging tests on the battery, obtains the charging voltage characteristic curve and the discharging voltage characteristic curve of the battery under different current and temperature conditions, and determines the radial line segment and the offset angle corresponding to each voltage value of the battery based on the charging voltage characteristic curve and the discharging voltage characteristic curve under a plurality of different current conditions and a plurality of different temperature conditions, respectively, and determines the radial line segment and the offset angle of the battery under each current condition, temperature condition, charging state and discharging state by a mathematical fitting method, thereby establishing the standard offset angle spectrum for storing the mapping relationship between the current value, the temperature, the voltage value and the offset angle of the battery.

[0132] In other embodiments, when determining the reference line and the reference point of the voltage characteristic curve in the target coordinate system, the estimation device needs to be determined according to the current working state of the battery. When the battery is in a charging state, the estimation device can determine the reference line and the reference point in the target coordinate system based on the charging cutoff voltage of the battery and the value point of the battery in the charging voltage characteristic curve when the battery is empty. When the battery is in a discharging state, the estimation device can determine the reference line and the reference point in the target coordinate system based on the discharging cutoff voltage of the battery and the value point of the battery in the discharging voltage characteristic curve when the battery is fully charged. Therefore, the above step S401 specifically includes the following two possible implementation manners.

[0133] In a possible implementation, when the battery is in a charging state, the voltage characteristic curve is a charging voltage characteristic curve, and the estimation device can determine the reference line and the reference point in the target coordinate system based on the charging cutoff voltage of the battery and the value point of the battery in the charging voltage characteristic curve when the battery is empty. Therefore, as shown in Figure 9 the above step S401 can be specifically implemented as the following steps S901-S902:

[0134] S901, in the case where the voltage characteristic curve is a charging voltage characteristic curve, determining, in the target coordinate system, a straight line parallel to the second axis and passing through the charging cutoff voltage of the battery in the charging voltage characteristic curve as the reference line.

[0135] As a possible implementation, when the battery is in a charging state, the voltage characteristic curve of the battery is a charging voltage characteristic curve, and in the target coordinate system, the estimation device can determine a straight line parallel to the second axis and passing through the charging cutoff voltage of the battery in the charging voltage characteristic curve as the reference line.

[0136] For example, the estimation device can determine the position of the charge cut-off voltage on the charge voltage characteristic curve in the target coordinate system, and determine a straight line passing through the position of the charge cut-off voltage and parallel to the second axis of the conventional coordinate system of the charge voltage characteristic curve as the reference line based on the position of the charge cut-off voltage. The charge cut-off voltage is the voltage of the battery when it reaches the fully charged state during the charging process. When the voltage value of the battery reaches the charge cut-off voltage, the battery usually stops charging in the constant current mode to prevent overcharging from damaging the performance and life of the battery.

[0137] S902, determining the mapping point of the value point of the battery's electric quantity with a null value on the reference line as the reference point.

[0138] As a possible implementation, after determining the reference line of the target coordinate system, the estimation device can also determine the value point of the battery's electric quantity with a null value in the charge voltage characteristic curve, and determine the mapping point of the value point on the reference line as the reference point based on the value point.

[0139] For example, the estimation device can determine the value point of the battery's electric quantity with a null value in the charge voltage characteristic curve, i.e., the value point of the initial time when the charging starts, and determine the perpendicular projection point of the value point on the reference line as the reference point.

[0140] Specifically, in general, the charge cut-off voltage of the above-mentioned LEP battery under normal temperature conditions is The estimation device can define the horizontal straight line where the charge cut-off voltage is located as the reference line of the target coordinate system, and define the point corresponding to the empty state (SOC=0%) of the LEP battery on the reference line as the reference point. Thus, the radial line segment is the line segment from the voltage value of the current time actually collected by the LEP battery during the charging process to the reference point, and the offset angle is the included angle between the radial line segment and the reference line. Since the value of the charge cut-off voltage should be greater than the voltage value of each time during the charging process of the LEP battery, in the target coordinate system, the charge voltage characteristic curve should be below the reference line, and thus the value range of the offset angle during the charging process of the LEP battery is The relationship among the voltage value of the current time of the battery, the charge cut-off voltage, and the meridian line segment is as follows:

[0141]

[0142] wherein V represents the voltage value of the current time of the battery, represents the charge cut-off voltage of the battery, r represents the radial distance corresponding to the voltage value of the current time in the target coordinate system, and θ represents the offset angle corresponding to the voltage value of the current time in the target coordinate system.

[0143] As an example, Figure 10 is a charging voltage characteristic curve diagram according to an example embodiment, Figure 10 is a segment of the charging voltage characteristic curve in the target coordinate system when the battery is charged at a certain current. As shown, Figure 10 the vertical direction perpendicular to the polar axis represents Voltage, i.e. the charging voltage value of the battery, in units of V. During the charging process, the voltage value of the battery changes from V1 to V2, the radial line segment changes from r1 to r2, and the offset angle changes from θ1 to θ2. Among them, V1 = 3.2577 V, V2 = 3.3424 V, r1 = 0.4157, r2 = 0.6295, and θ1 = -1.235 and θ2 = -0.4995 can be obtained by the formula in the above steps. Therefore, when the mapping relationship between the offset angle and the SOC value is a linear mapping relationship, the SOC value corresponding to the offset angles θ1 and θ2 can be obtained based on the formula in the above step S103, SOC1 = 21.4%, and SOC2 = 68.2%.

[0144] In another possible implementation, when the battery is in a discharging state, the voltage characteristic curve is a discharging voltage characteristic curve, and the estimation device can determine the reference line and the reference point in the target coordinate system based on the discharging cutoff voltage of the battery and the value point of the battery when fully charged in the discharging voltage characteristic curve. Therefore, as shown in Figure 11 the above step S401 can be implemented as the following steps S1101-S1102:

[0145] S1101, in the case of a discharging voltage characteristic curve, in the target coordinate system, determining a straight line parallel to the second axis of the discharging voltage characteristic curve of the battery as the reference line.

[0146] As a possible implementation, when the battery is in a discharging state, the voltage characteristic curve of the battery is a discharging voltage characteristic curve, and in the target coordinate system, the estimation device can determine a straight line parallel to the second axis of the discharging voltage characteristic curve of the battery as the reference line.

[0147] For example, the estimation device can determine the position of the discharging cutoff voltage on the discharging voltage characteristic curve in the target coordinate system, and then determine a straight line passing through the position of the discharging cutoff voltage and parallel to the second axis of the conventional coordinate system of the discharging voltage characteristic curve as the reference line. The discharging cutoff voltage is the lowest working voltage of the battery when the voltage of the battery drops to the point where it cannot be discharged during discharging. When the voltage value of the battery reaches the discharging cutoff voltage, the battery will usually stop discharging to prevent the battery from being damaged by excessive discharge of the battery.

[0148] S1102, determine the mapping point of the value point of the battery in the discharge voltage characteristic curve with full value on the reference line as the reference point.

[0149] As a possible implementation, the estimation device determines the reference line of the target coordinate system, and then determines the value point of the battery in the discharge voltage characteristic curve with full value, so as to determine the mapping point of the value point on the reference line as the reference point.

[0150] For example, the estimation device can determine the value point of the battery in the discharge voltage characteristic curve with full value, that is, the value point of the initial time when the discharge starts in the discharge voltage characteristic curve, so as to determine the vertical projection point of the value point on the reference line as the reference point.

[0151] Specifically, generally, the discharge cut-off voltage of the above-mentioned LEP battery under normal temperature condition The estimation device can define the horizontal straight line where the discharge cut-off voltage is located as the reference line of the target coordinate system, and define the point on the reference line corresponding to the full charge state (SOC=100%) of the LEP battery as the reference point. Thus, the radial line segment is the line segment from the current voltage value of the LEP battery actually collected in the discharge process to the reference point, and the offset angle is the included angle between the radial line segment and the reference line. Since the value of the discharge cut-off voltage should be less than the voltage value of the LEP battery at each time in the discharge process, in the target coordinate system, the discharge voltage characteristic curve should be above the reference line, and thus the value range of the offset angle in the LEP battery discharge process is The relationship among the current voltage value of the battery, the discharge cut-off voltage and the meridian line segment is as follows:

[0152]

[0153] Wherein, V represents the current voltage value of the battery, represents the discharge cut-off voltage of the battery, r represents the radial distance corresponding to the current voltage value in the target coordinate system, and θ represents the offset angle corresponding to the current voltage value in the target coordinate system.

[0154] As an example, Figure 12 is another discharge voltage characteristic curve diagram shown according to an exemplary embodiment, Figure 12 is a discharge voltage characteristic curve of the battery in the target coordinate system when the battery is discharged at a certain current. As Figure 12As shown, the direction perpendicular to the polar axis represents Voltage, i.e., the battery's discharge voltage value, in V. During discharge, the battery voltage value changes from V1 to V2, the radial line segment changes from r1 to r2, and the offset angle changes from θ1 to θ2. Where V1 = 3.3097V, V2 = 3.2679V, r1 = 0.8213, r2 = 0.9441, and using the formulas in the above steps, we can obtain θ1 = 1.403 and θ2 = 0.9503. Therefore, when the mapping relationship between the offset angle and the SOC value is linear, based on the formula in step S103 above, we can obtain the SOC values ​​corresponding to the offset angles θ1 and θ2: SOC1 = 89.3% and SOC2 = 60.5%.

[0155] The above are embodiments of the battery state of charge estimation method provided in this application. For ease of understanding, the above battery state of charge estimation method will be further explained below in the form of examples.

[0156] Figure 13 This is a flowchart illustrating yet another method for estimating the state of charge of a battery according to an exemplary embodiment, such as... Figure 13 As shown, the process includes the following steps: S1301, Selecting suitable poles to establish a polar coordinate system (equivalent to step S401 above, determining the baseline and reference point of the voltage characteristic curve in the target coordinate system). S1302, Calculating the polar angle θ based on the voltage value and the polar radius (equivalent to step S402 above, determining the radial line segment corresponding to the current voltage value based on the current voltage value and the reference point, and step S403 above, determining the offset angle corresponding to the current voltage value based on the radial line segment and the baseline). S1303, Determining the mapping relationship between the polar angle θ and SOC and calculating SOC based on this mapping relationship (equivalent to step S103 above, determining the SOC value of the battery at the current moment based on the mapping relationship and the offset angle corresponding to the current voltage value).

[0157] The foregoing mainly describes the solutions provided by the embodiments of this application from a methodological perspective. To achieve the above functions, the battery state-of-charge estimation device or vehicle includes corresponding hardware structures and / or software modules for performing each function. Those skilled in the art should readily recognize that, based on the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0158] This application embodiment can, based on the above method, exemplarily divide a battery state of charge estimation device or vehicle into functional modules. For example, the battery state of charge estimation device or vehicle may include various functional modules corresponding to each functional division, or two or more functions may be integrated into one processing module. The integrated module can be implemented in hardware or as a software functional module. It should be noted that the module division in this application embodiment is illustrative and only represents one logical functional division; in actual implementation, there may be other division methods.

[0159] Figure 14 This is a block diagram illustrating a battery state-of-charge estimation device according to an exemplary embodiment. (Refer to...) Figure 14 The battery state of charge estimation device 1400 includes an acquisition module 1401 and a determination module 1402.

[0160] The acquisition module 1401 is used to acquire the battery voltage value at the current moment. The determination module 1402 is used to determine the offset angle corresponding to the current voltage value based on the current voltage value. The offset angle corresponding to the current voltage value is used to characterize the relationship between the battery capacity corresponding to the current voltage value and the current voltage value in the battery voltage characteristic curve. The determination module 1402 is also used to determine the SOC value of the battery at the current moment based on the mapping relationship and the offset angle corresponding to the current voltage value. The mapping relationship is a one-to-one correspondence between the offset angle determined based on the battery voltage value and the actual battery capacity during operation and the SOC value.

[0161] In one possible implementation, the aforementioned determining module 1402 is specifically used to acquire the battery's temperature and current at the current moment; determine the battery's voltage characteristic curve at the current moment based on the current temperature and current; and determine the offset angle corresponding to the current voltage value based on the current voltage value and voltage characteristic curve.

[0162] In a possible implementation, the determining module 1402 is specifically configured to: determine, in the target coordinate system, a reference line and a reference point of the voltage characteristic curve, the coordinate system in which the voltage characteristic curve is located includes a first axis and a second axis perpendicular to each other, the first axis is used to represent a voltage value of the battery, the second axis is used to represent a power value of the battery, the reference line is parallel to the second axis, and a voltage value at an intersection of the reference line and the first axis is a cut-off voltage of the battery, the reference point is a mapping point of a value point of the battery in a full charge state or a fully discharged state on the reference line, determine, according to the voltage value at the current moment and the reference point, a radial line segment corresponding to the voltage value at the current moment, the radial line segment is a line segment between the value point at the voltage value at the current moment in the voltage characteristic curve and the reference point in the target coordinate system, and determine, according to the radial line segment and the reference line, an offset angle corresponding to the voltage value at the current moment, the offset angle being an angle of an included angle between the radial line segment and the reference line.

[0163] In a possible implementation, the determining module 1402 is specifically configured to: in a case where the voltage characteristic curve is a charging voltage characteristic curve, determine, in the target coordinate system, a straight line parallel to the second axis and passing through the charging cut-off voltage of the battery in the charging voltage characteristic curve as the reference line, and determine, in the target coordinate system, a mapping point of a value point of the battery in the charging voltage characteristic curve, in which the power value is a null value, on the reference line as the reference point.

[0164] In a possible implementation, the determining module 1402 is specifically configured to: in a case where the voltage characteristic curve is a discharging voltage characteristic curve, determine, in the target coordinate system, a straight line parallel to the second axis and passing through the discharging cut-off voltage of the battery in the discharging voltage characteristic curve as the reference line, and determine, in the target coordinate system, a mapping point of a value point of the battery in the discharging voltage characteristic curve, in which the power value is a full value, on the reference line as the reference point.

[0165] In a possible implementation, the determining module 1402 is specifically configured to: obtain a current value and a temperature of the battery at the current moment, and find, based on the current value, the temperature, the voltage value at the current moment, and a standard offset angle spectrum, the offset angle corresponding to the voltage value at the current moment, the standard offset angle spectrum being used to indicate a mapping relationship between the current value, the temperature, the voltage value, and the offset angle of the battery.

[0166] In a possible implementation, the mapping relationship includes any one of the following: a linear mapping, a trigonometric function mapping, an exponential function mapping, a logarithmic function mapping, a power function mapping, a polynomial function mapping, and a Gaussian function mapping.

[0167] In a possible implementation, the target coordinate system includes any one of the following: a polar coordinate system, a spherical coordinate system, and a cylindrical coordinate system.

[0168] According to the above technical means, the offset angle contains the relationship between the voltage value at the current moment and the corresponding electric quantity in the voltage characteristic curve, compared with directly determining the SOC value of the battery based on the voltage value in the related art, the SOC value is determined based on the offset angle in the application, which considers multiple parameters of the battery, so that the SOC value is more accurate. Moreover, the mapping relationship between the offset angle and the SOC value of the battery can be determined based on the voltage value and the actual battery electric quantity of the battery in the running process, so that the influence of the aging condition, the use condition and the like of the battery on the battery capacity in the use process is considered, so that the mapping relationship can more accurately reflect the actual running state of the battery, and the estimation accuracy of the SOC value is improved.

[0169] As to the device in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be described in detail here.

[0170] Figure 15 is a block diagram of a vehicle according to an example embodiment. As shown in Figure 15 , the vehicle 1500 includes, but is not limited to, a processor 1501 and a memory 1502.

[0171] The memory 1502 described above is configured to store executable instructions of the processor 1501 described above. It can be understood that the processor 1501 is configured to execute the instructions to implement the battery state of charge estimation method in the above embodiment.

[0172] It should be noted that those skilled in the art can understand that Figure 15 the vehicle structure shown in the above embodiment does not constitute a limitation on the vehicle, and the vehicle can include more or fewer components than Figure 15 shown, or combine certain components, or different component arrangements.

[0173] The processor 1501 is the control center of the vehicle, which connects various parts of the vehicle through various interfaces and lines, executes software programs and / or modules stored in the memory 1502, and calls data stored in the memory 1502, to perform various functions of the vehicle and process data, thereby overall monitoring the vehicle. The processor 1501 can include one or more processing units. Optionally, the processor 1501 can integrate an application processor and a modem processor, wherein the application processor mainly processes the operating system, user interface and application programs, and the modem processor mainly processes wireless communication. It can be understood that the above-mentioned modem processor can also not be integrated into the processor 1501.

[0174] The memory 1502 can be used to store software programs and various data. The memory 1502 can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, application programs (such as a determination unit, a processing unit, etc.) required by at least one function module, and the like. In addition, the memory 1502 can include a high-speed random access memory, and can also include a non-volatile memory, for example, at least one magnetic disk storage device, a flash memory device, or other volatile solid-state memory device.

[0175] In the example embodiment, a computer readable storage medium including instructions, for example, the memory 1502 including instructions, is also provided, and the instructions can be executed by the processor 1501 of the vehicle 1500 to implement the battery state of charge estimation method in the above embodiment.

[0176] In actual implementation, Figure 14 The functions of the acquisition module 1401 and the determination module 1402 in the above embodiment can be implemented by the processor 1501 calling the computer program stored in the memory 1502. The specific execution process can refer to the description of the method part in the above embodiment, and will not be described here. Figure 15 The functions of the acquisition module 1401 and the determination module 1402 in the above embodiment can be implemented by the processor 1501 calling the computer program stored in the memory 1502. The specific execution process can refer to the description of the method part in the above embodiment, and will not be described here.

[0177] Alternatively, the computer readable storage medium can be a non-transitory computer readable storage medium, for example, the non-transitory computer readable storage medium can be a read-only memory (ROM), a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, and an optical data storage device, etc.

[0178] In the example embodiment, the embodiment of the present application also provides a computer program product including one or more instructions, which can be executed by the processor 1501 of the vehicle to complete the battery state of charge estimation method in the above embodiment.

[0179] It should be noted that the instructions in the above computer readable storage medium or the one or more instructions in the computer program product are executed by the processor of the vehicle to implement each process of the above method embodiment, and can achieve the same technical effect as the above method. To avoid repetition, it will not be described here.

[0180] Through the description of the above embodiments, those skilled in the art can clearly understand that, for the convenience and brevity of description, only the above division of functional modules is taken as an example for illustration, and in actual application, the above functions can be completed by different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete the above described full classification part or part of the function.

[0181] In several embodiments provided in the present application, it should be understood that the disclosed apparatus and method can be implemented by other manners. For example, the apparatus embodiments described above are merely illustrative, for example, the division of the modules or units is merely a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another apparatus, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units or components shown or discussed can be indirect coupling or communication connection through some interfaces, apparatuses or units, and can be electrical, mechanical or other forms.

[0182] The units described as separate components can or can not be physically separate, and the components shown as units can be one physical unit or a plurality of physical units, that is, can be located in one place, or can be distributed to a plurality of different places. Part or all of the classification units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0183] In addition, the functional units in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0184] If the integrated unit is realized in the form of a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solutions of the embodiments of the present application essentially or the part of the prior art that contributes to the technical solutions or the whole classification or part of the technical solutions can be embodied in the form of a software product, which is stored in a storage medium and includes a plurality of instructions for making a device (which can be a single chip, a chip, etc.) or a processor execute all or part of the steps of the method of the embodiments of the present application. The foregoing storage medium includes: U disk, mobile hard disk, ROM, RAM, magnetic disk or optical disk and various program code storage media.

[0185] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any change or replacement within the technical scope disclosed in the present application should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method of estimating a state of charge of a battery, characterized by, The method comprises: acquiring a voltage value of the battery at a current time; determining an offset angle corresponding to the voltage value at the current time according to the voltage value at the current time; the offset angle corresponding to the voltage value at the current time is used to represent a relationship between a battery capacity corresponding to the voltage value at the current time and the voltage value at the current time in a voltage characteristic curve of the battery; determining an SOC value of the battery at the current time according to a mapping relationship and the offset angle corresponding to the voltage value at the current time; the mapping relationship is a one-to-one correspondence between offset angles and SOC values determined based on voltage values and actual battery capacities of the battery in an operation process of the battery; the determination of the offset angle corresponding to the voltage value at the current time according to the voltage value at the current time comprises: acquiring a temperature and a current of the battery at the current time; determining a voltage characteristic curve of the battery at the current time based on the temperature and the current at the current time; determining a reference line and a reference point of the voltage characteristic curve in a target coordinate system; the coordinate system in which the voltage characteristic curve is located comprises a first axis and a second axis perpendicular to each other; the first axis is used to represent a voltage value of the battery; the second axis is used to represent an electric quantity of the battery; the reference line is parallel to the second axis, and a voltage value at an intersection of the reference line and the first axis is a cut-off voltage of the battery; the reference point is a mapping point of a value point of the battery in a full charge state or a fully discharged state on the reference line in the voltage characteristic curve; determining a radial line segment corresponding to the voltage value at the current time according to the voltage value at the current time and the reference point; the radial line segment is a line segment between the value point at the voltage value at the current time and the reference point in the voltage characteristic curve in the target coordinate system; determining the offset angle corresponding to the voltage value at the current time according to the radial line segment and the reference line; the offset angle is an angle of an included angle between the radial line segment and the reference line.

2. The method of claim 1, wherein, the determination of the reference line and the reference point of the voltage characteristic curve in the target coordinate system comprises: in a case where the voltage characteristic curve is a charging voltage characteristic curve, determining, in the target coordinate system, a straight line parallel to a charging cut-off voltage of the battery in the charging voltage characteristic curve and the second axis as the reference line; determining a mapping point of a value point of the battery in the charging voltage characteristic curve as the reference point, the value point being a null value of the electric quantity on the reference line.

3. The method of claim 2, wherein, the determination of the reference line and the reference point of the voltage characteristic curve in the target coordinate system comprises: in a case where the voltage characteristic curve is a discharging voltage characteristic curve, determining, in the target coordinate system, a straight line parallel to a discharging cut-off voltage of the battery in the discharging voltage characteristic curve and the second axis as the reference line; determining a mapping point of a value point of the battery in the discharging voltage characteristic curve as the reference point, the value point being a full value of the electric quantity on the reference line.

4. The method of claim 1, wherein, The mapping relationship includes any one of the following: linear mapping, trigonometric function mapping, exponential function mapping, logarithmic function mapping, power function mapping, polynomial function mapping, and Gaussian function mapping.

5. The method according to any one of claims 1 to 3, characterized in that, The target coordinate system includes any one of the following: polar coordinate system, spherical coordinate system, and cylindrical coordinate system.

6. A battery state-of-charge estimation device characterized by comprising: The device includes an acquisition module and a determination module. The acquisition module is configured to acquire a voltage value of the battery at a current time point. The determination module is configured to determine an offset angle corresponding to the voltage value at the current time point according to the voltage value at the current time point, wherein the offset angle represents a relationship between a battery capacity corresponding to the voltage value at the current time point and the voltage value at the current time point in a voltage characteristic curve of the battery. The determination module is further configured to determine an SOC value of the battery at the current time point according to a mapping relationship and the offset angle corresponding to the voltage value at the current time point, wherein the mapping relationship is a one-to-one correspondence between the offset angle and the SOC value, which is determined based on the voltage value and the actual battery capacity of the battery during operation. The determination module is specifically configured to: acquire a temperature and a current of the battery at the current time point; determine a voltage characteristic curve of the battery at the current time point based on the temperature and the current at the current time point; determine a reference line and a reference point of the voltage characteristic curve in a target coordinate system, wherein the coordinate system in which the voltage characteristic curve is located includes a first axis and a second axis perpendicular to each other, the first axis is used to represent the voltage value of the battery, the second axis is used to represent the capacity of the battery, the reference line is parallel to the second axis, and the voltage value at the intersection of the reference line and the first axis is the cutoff voltage of the battery, and the reference point is a mapping point of a value point of the battery in a full charge state or a fully discharged state on the reference line in the voltage characteristic curve; determine a radial line segment corresponding to the voltage value at the current time point according to the voltage value at the current time point and the reference point, wherein the radial line segment is a line segment between the value point at the voltage value at the current time point in the voltage characteristic curve and the reference point in the target coordinate system; determine an offset angle corresponding to the voltage value at the current time point according to the radial line segment and the reference line, wherein the offset angle is an angle of an included angle between the radial line segment and the reference line.

7. A vehicle characterized by comprising: include: a processor; a memory for storing instructions executable by the processor; wherein the processor is configured to execute the instructions to implement the method of any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, When the computer-executable instructions stored in the computer-readable storage medium are executed by the processor of the vehicle, the vehicle is capable of performing the method of any one of claims 1 to 5.

9. A computer program product, characterised in that, The computer program product includes computer instructions that, when executed on a vehicle, cause the vehicle to perform the method of any one of claims 1 to 5.

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