CN112986842B - Method, device and equipment for estimating state of charge of battery - Google Patents
Method, device and equipment for estimating state of charge of battery Download PDFInfo
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- CN112986842B CN112986842B CN201911300926.1A CN201911300926A CN112986842B CN 112986842 B CN112986842 B CN 112986842B CN 201911300926 A CN201911300926 A CN 201911300926A CN 112986842 B CN112986842 B CN 112986842B
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- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/382—Arrangements for monitoring battery or accumulator variables, e.g. SoC
- G01R31/3842—Arrangements for monitoring battery or accumulator variables, e.g. SoC combining voltage and current measurements
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/389—Measuring internal impedance, internal conductance or related variables
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Abstract
The application provides a method for estimating the state of charge of a battery, which comprises the following steps: according to the current battery temperature and the first battery state-of-charge value, searching in a relational mapping table to obtain the current battery internal resistance value of the battery, and determining the current open-circuit voltage of the battery according to the current battery voltage at two ends, the current battery internal resistance value and the current charging/discharging current; determining a first state of charge value of the battery at the current moment according to the open-circuit voltage of the battery at the current moment and a preset corresponding relation between the open-circuit voltage and the state of charge; and calculating to obtain the output state of charge value of the battery at the current moment according to the first state of charge value of the battery at the current moment, the change capacity of the battery from the first moment to the current moment and the rated capacity of the battery. By implementing the method and the device, the first state of charge value of the battery at the current moment is corrected, and the accuracy of estimation of the output state of charge value of the battery at the current moment is improved.
Description
Technical Field
The application relates to the technical field of batteries, in particular to a method, a device and equipment for estimating the state of charge of a battery.
Background
New energy vehicles are receiving more and more attention, and a power battery is a core component of an electric vehicle. In order to make a battery safer and more efficient, the battery needs to be managed, and the key point of battery management is to accurately estimate the State of the battery, and the State of Charge (SOC) of the battery reflects the available remaining capacity of the battery, which is one of the most important parameters in a battery management system, so that the battery management system has important significance in preventing over-Charge and over-discharge of the battery in a battery management system of an electric vehicle, improving the use efficiency, ensuring the use safety, prolonging the service life and estimating the endurance time and capacity.
In the prior art, the state of charge of a battery is estimated by using a method combining an open-circuit voltage method and an ampere-hour integration method, the open-circuit voltage method is to measure and obtain the voltages at two ends of the battery under the condition of no load connection as the open-circuit voltage of the battery at a first moment, and the state of charge value of the battery at the first moment is determined by using the corresponding relation between the open-circuit voltage and the state of charge, the ampere-hour integration method is to calculate the input and output charge number of the battery from the first moment to the current moment, and the current state of charge value is obtained from the state of charge value of the battery at the first moment and the input and output charge number of the battery from the first moment to the current moment.
Disclosure of Invention
The application provides an estimation method of a battery state of charge, which is used for correcting a first state of charge value of a battery at the current moment and improving the accuracy of estimation of the output state of charge of the battery at the current moment.
In a first aspect, an embodiment of the present application provides a method for estimating a state of charge of a battery, where the method includes:
according to the current battery temperature of a target battery and the state of charge value of the target battery at a first moment, searching a relation mapping table to obtain the current battery internal resistance value of the target battery, wherein the relation mapping table comprises the corresponding relation among the current battery internal resistance value, the battery temperature and the state of charge value of the target battery, and the first moment is the state of charge estimation moment which is away from the current moment by a first time interval;
obtaining the voltage of the target battery at two ends of the battery at the current moment, and determining the open-circuit voltage of the target battery at the current moment according to the voltage of the target battery at two ends of the battery at the current moment, the internal resistance value of the battery at the current moment and the charging/discharging current at the current moment;
determining a first state of charge value of the target battery at the current moment according to the open-circuit voltage of the target battery at the current moment and a preset corresponding relation between the open-circuit voltage and the state of charge;
and calculating to obtain an output state of charge value of the target battery at the current moment according to the first state of charge value of the target battery at the current moment, the change capacity of the target battery from the first moment to the current moment and the rated capacity of the target battery.
In a possible implementation manner, the step of obtaining, by searching in a map, a battery internal resistance value of a target battery at a current time according to a battery temperature of the target battery at the current time and a state of charge value of the target battery at a first time includes:
acquiring the voltage of the two ends of the target battery at the initial moment, and taking the voltage of the two ends of the target battery at the initial moment as the open-circuit voltage of the target battery at the initial moment; the initial time is the measurement time after the target battery is charged/discharged for the last time;
and determining an initial state of charge value of the target battery according to the open-circuit voltage of the target battery at the initial moment and the corresponding relation between the preset open-circuit voltage and the preset state of charge, wherein the initial state of charge value is a fixed value.
Further, the method further comprises:
and calculating to obtain the corrected rated capacity of the target battery according to the difference between the first state of charge value of the target battery at the current moment and the initial state of charge value of the target battery and the accumulated capacity of the target battery from the initial moment to the current moment, and taking the corrected rated capacity as the rated capacity of the target battery at the next time interval at the current moment.
Optionally, the method further includes:
acquiring a plurality of first state of charge values of the target battery at a plurality of different moments, and respectively calculating a plurality of rated capacities of the target battery after correction according to differences between the plurality of first state of charge values and an initial state of charge value of the target battery and a plurality of accumulated capacities of the target battery from the initial moment to the moments when the plurality of first state of charge values are respectively acquired;
and if the difference between the plurality of rated capacities corrected by the target battery and the average of the plurality of rated capacities corrected by the target battery is smaller than a first preset threshold, taking the average of the plurality of rated capacities corrected by the target battery as the rated capacity corrected by the target battery.
In one possible embodiment, the taking the corrected rated capacity as the rated capacity of the target battery for the next time interval at the current time includes:
and determining that the difference value between the first state of charge value of the target battery at the current moment and the initial state of charge value of the target battery is larger than a second preset threshold value.
In one possible implementation, the determining the first state of charge value of the target battery at the current time includes:
determining that the state of the target battery meets a preset condition, wherein the preset condition is that the state of charge value of the target battery at a first moment is in a first preset interval, and/or the charge/discharge current of the target battery at the current moment is smaller than a third preset threshold.
Optionally, the step of obtaining, according to the first state of charge value of the target battery at the current time, the change capacity of the target battery from the first time to the current time, and the rated capacity of the target battery includes:
integrating a first preset battery current from the first moment to the current moment to obtain the change capacity of the target battery from the first moment to the current moment, wherein the first preset battery current is the charge/discharge current of the target battery from the first moment to the current moment;
dividing the change capacity of the target battery from the first moment to the current moment by the rated capacity of the target battery to obtain the capacity change proportion of the target battery from the first moment to the current moment;
and subtracting the capacity change proportion of the target battery from the first moment to the current moment from the first state of charge value of the target battery at the current moment to obtain the state of charge value of the target battery at the current moment.
In a second aspect, an embodiment of the present application provides a battery state of charge estimation apparatus, including:
the system comprises a searching module, a relation mapping table and a control module, wherein the searching module is used for searching and obtaining the internal resistance value of a target battery at the current moment in the relation mapping table according to the battery temperature of the target battery at the current moment and the state of charge value of the target battery at a first moment;
the acquisition module is used for acquiring the voltage of the two ends of the target battery at the current moment;
the determining module is used for determining the open-circuit voltage of the target battery at the current moment according to the voltage of the two ends of the target battery at the current moment, the internal resistance value of the battery at the current moment and the charging/discharging current at the current moment;
the determining module is further configured to determine a first state of charge value of the target battery at the current moment according to the open-circuit voltage of the target battery at the current moment and a preset corresponding relationship between the open-circuit voltage and the state of charge;
and the calculation module is used for calculating to obtain the output state of charge value of the target battery at the current moment according to the first state of charge value of the target battery at the current moment, the change capacity of the target battery from the first moment to the current moment and the rated capacity of the target battery.
In a third aspect, an embodiment of the present application provides an electronic device, which includes a processor and a memory, where the processor is configured to execute a computer program stored in the memory, and implement the method steps of the foregoing aspects and any one of the possible embodiments.
In a fourth aspect, the present application further provides a computer-readable storage medium, which stores instructions that, when executed on a computer, cause the computer to perform the method steps of the above aspects and any one of the possible embodiments.
In the application, a battery state of charge estimation device searches a relation mapping table according to the current battery temperature of a target battery and the first-moment state of charge value of the target battery to obtain the current-moment internal resistance value of the target battery, obtains the voltages at two ends of the target battery at the current moment, and determines the current-moment open-circuit voltage of the target battery according to the current-moment voltage of the target battery, the current-moment internal resistance value of the battery and the current-moment charging/discharging current; determining a first state of charge value of the target battery at the current moment according to the open-circuit voltage of the target battery at the current moment and a preset corresponding relation between the open-circuit voltage and the state of charge; and calculating to obtain the output state of charge value of the target battery at the current moment according to the first state of charge value of the target battery at the current moment, the change capacity of the target battery from the first moment to the current moment and the rated capacity of the target battery. By implementing the method and the device, the first state of charge value of the target battery at the current moment is corrected, and the accuracy of estimation of the output state of charge value of the battery at the current moment is improved.
Drawings
Fig. 1 is a schematic flowchart of a method for estimating a state of charge of a battery according to an embodiment of the present disclosure;
fig. 2 is a graph of an open-circuit voltage and a state of charge of a battery according to an embodiment of the present disclosure;
fig. 3 is a battery equivalent model provided in an embodiment of the present application;
FIG. 4 is a schematic flow chart illustrating another method for estimating a state of charge of a battery according to an embodiment of the present disclosure;
fig. 5 is a device for estimating a state of charge of a battery according to an embodiment of the present application;
fig. 6 is an electronic device according to an embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The following describes embodiments of the present application in further detail with reference to the accompanying drawings. See fig. 1-3.
Referring to fig. 1, an embodiment of the present application provides a method for estimating a state of charge of a battery, where the method includes:
s100, searching a relation mapping table to obtain the internal resistance value of the target battery at the current moment according to the current-moment battery temperature of the target battery and the first-moment state-of-charge value of the target battery, wherein the relation mapping table comprises the corresponding relation among the internal resistance value of the target battery, the battery temperature and the state-of-charge value, and the first moment is the state-of-charge estimation moment which is a first time interval away from the current moment.
In a possible embodiment, the estimation device of the battery state of charge comprises, before executing step S100: the estimation device of the battery state of charge acquires the voltages of two ends of the target battery at the initial moment, and the voltages of two ends of the target battery at the initial moment are used as the open-circuit voltage of the target battery at the initial moment; the initial time is the measurement time after the target battery is charged/discharged for the last time; and determining an initial state of charge value of the target battery according to the open-circuit voltage of the target battery at the initial moment and the corresponding relation between the preset open-circuit voltage and the preset state of charge, wherein the initial state of charge value is a fixed value. Specifically, the voltage across the battery measured by standing for a certain period of time after the end of charge/discharge of the battery may be regarded as the open-circuit voltage of the battery, so the initial time may be a measurement time at which the target battery has been left standing for a long time after the end of the last charge/discharge of the target battery. For example, reference may be made to fig. 2 for the preset correspondence between the open-circuit voltage and the state of charge, where fig. 2 is a graph of the open-circuit voltage and the state of charge of the battery according to an embodiment of the present disclosure. Alternatively, the graph shown in fig. 2 may be plotted as a functional expression. And the estimation device of the state of charge of the battery acquires the open-circuit voltage of the target battery at the initial moment, and substitutes the open-circuit voltage of the target battery at the initial moment into the functional expression to determine the initial state of charge value of the target battery.
In one possible implementation, the state of charge value of the target battery at the first time is an initial state of charge value of the target battery.
In another possible implementation manner, the state of charge value of the target battery at the first time is calculated from the initial state of charge value of the target battery, and the specific calculation formula is as follows:
wherein SOC (t)1) Is at the t1State of charge value at time, when t1When the current time is the first time, the result calculated by the formula 1 is the state of charge value of the target battery at the first time; SOC (t)01) For the target battery at an initial time t01I is a charge/discharge current of the target battery from the initial time to the first time, and Q is a rated capacity of the target battery. It is understood that the estimation device of the state of charge of the battery calculates the state of charge of the target battery at a certain time interval, the first time differs from the current time by the first time interval, and the state of charge of the target battery at the first time can be considered as a known value stored in the estimation device of the state of charge of the battery.
The battery temperature of the target battery at the current moment can be measured by the temperature sensor in real time. The relation mapping table includes a corresponding relation among the battery internal resistance value, the battery temperature and the state of charge value of the target battery, the relation mapping table can also be regarded as a known condition pre-stored in the estimation device of the state of charge of the battery, and the relation mapping table is data obtained by carrying out a large number of experimental tests on the target battery or the battery which is of the same type as the target battery or even the battery of the same manufacturer and the same production batch. The following is an exemplary illustration of the RelationMap:
taking a battery with a rated capacity of 1200mAh as an example, discharging with a current of 1C, where 1C represents 1200mA (1 multiplying power of 1200 mAh), and referring to the method described above in connection with fig. 2 for obtaining the initial state of charge value of the battery, first placing the target battery in a thermostat at 25 ℃ to obtain the initial state of charge value of the target battery as 100%, and the battery temperature of the target battery is 25 ℃; in the experimental process, the current of 1C is used for discharging, 100% of the battery can be discharged in 1 hour, the electric quantity of the battery is reduced by 10% every 6 minutes, the battery internal resistance of the target battery at the initial moment can be identified in one recording cycle by taking 6 minutes as a recording cycle, illustratively, the voltage difference of the target battery within 6 minutes from the initial moment is obtained, and the battery internal resistance of the target battery at the initial moment is obtained by dividing the voltage difference by the discharging current of 1200mA according to ohm's law; after 6 minutes, the charge state of the target battery is 90%, the battery temperature of the target battery is still 25 ℃ in the thermostat, the voltage difference within the second 6 minutes is obtained, and the battery internal resistance value of the target battery at the moment is calculated to be 0.15 omega according to ohm's law; by analogy, the obtained mapping relation table is shown in table 1:
table 1
| State of charge SOC/%) | Temperature/. degree.C | Internal resistance/omega of |
| 100 | 25 | 0.1 |
| 90 | 25 | 0.2 |
| 80 | 25 | 0.22 |
| …… | …… | …… |
The estimation device of the state of charge of the battery obtains the t th by calculation according to a formula 11State of charge SOC (t) at time1) Then, after the first time interval, obtaining the battery temperature T of the target battery at the current moment T, and according to the battery temperature T of the target battery at the current moment T and the tth time1State of charge SOC (t) at time1) The internal resistance value of the target battery at the current time t is found in a relational mapping table such as table 1, optionally, a plurality of relational mapping tables can be established for the internal resistance values of the battery at different temperatures of the same SOC, and when different state of charge values of the target battery at the first time are obtained, the relational mapping tables corresponding to the different state of charge values are found, and the representation form of the relational mapping tables is not limited in the present application. For example, the estimation device of the battery state of charge obtains that the state of charge value of the target battery at the first time is 90%, the temperature of the target battery at the current time is 25 ℃, and the lookup table 1 determines that the internal resistance value of the target battery at the current time is 0.2 Ω.
S101, the estimation device of the state of charge of the battery acquires the voltages of the two ends of the target battery at the current moment, and the open-circuit voltage of the target battery at the current moment is determined according to the voltages of the two ends of the target battery at the current moment, the internal resistance value of the battery at the current moment and the charging/discharging current at the current moment. Specifically, the target battery is equivalent to a model in which a power supply is connected in series with a resistor, see fig. 3, and fig. 3 is a battery equivalent model provided in an embodiment of the present application. As shown in fig. 3, the open-circuit voltage OCV of the target battery at the present time is:
OCV ═ U + I × R formula 2
U is the voltage of the two ends of the target battery at the current moment, I is the charging/discharging current of the target battery at the current moment, and R is the internal resistance value of the target battery at the current moment. Illustratively, U is acquired by a voltage sensor, I is acquired by a hall current sensor, and R is acquired by looking up a mapping table in step S100.
S102, the estimation device of the battery state of charge determines a first state of charge value of the target battery at the current moment according to the open-circuit voltage of the target battery at the current moment and the preset corresponding relation between the open-circuit voltage and the state of charge. Specifically, the estimation device of the state of charge of the battery obtains the open-circuit voltage OCV of the target battery at the current time through calculation in step S101, and searches a graph between the open-circuit voltage and the state of charge shown in fig. 2 according to the open-circuit voltage OCV of the target battery at the current time to obtain the first state of charge value of the target battery at the current time. Optionally, the corresponding relationship between the open-circuit voltage and the state of charge of the target battery may also be represented by a functional expression, and the open-circuit voltage at the current time of the target battery is substituted into the functional expression, so as to calculate the first state of charge value at the current time of the target battery.
In one possible implementation, the determining, by the battery state-of-charge estimation device, the first state-of-charge value of the target battery at the current time includes: determining that the state of the target battery meets a preset condition, wherein the preset condition is that the state of charge value of the target battery at a first moment is in a first preset interval, and/or the charge/discharge current of the target battery at the current moment is smaller than a third preset threshold.
Specifically, referring to the graph between the open-circuit voltage and the state of charge of the battery shown in fig. 2, it can be found that within a certain interval of the state of charge value of the target battery, for example, within a range of 0.2 to 0.6, the open-circuit voltage of the target battery has a small variation range, i.e., it can be understood that a small variation of the open-circuit voltage causes a large variation of the state of charge value, in order to reduce the error of the state of charge value of the target battery at the first time, the battery state of charge estimation apparatus first determines whether the state of charge value of the target battery at the first time is within the range of the first preset interval, for example, within a range of 0 to 0.2 or within a range of 0.6 to 1, and if the state of charge value of the target battery at the first time is within the first preset interval, it is determined that the first state of charge value of the target battery at the current time obtained through steps S101 to S102 is relatively accurate, otherwise, the state of charge value at the initial moment is used as the first state of charge value of the target battery at the current moment.
Optionally, in order to reduce the influence of the battery polarization effect on the battery state of charge estimation, the battery state of charge estimation device first determines whether the charge/discharge current of the target battery at the current time is smaller than a third preset threshold, for example, 100mA, if the charge/discharge current of the target battery at the current time is smaller than 100mA, it is determined that the charge/discharge current I of the target battery in step S102 formula 2 can reduce the estimation influence caused by the polarization effect, and a relatively correct open-circuit voltage can be obtained from formula 2, so as to improve the accuracy of the first state of charge value of the target battery at the current time, otherwise, the above-mentioned state of charge value at the initial time is used as the first state of charge value of the target battery at the current time.
S103, calculating to obtain an output state of charge value of the target battery at the current moment according to the first state of charge value of the target battery at the current moment, the change capacity of the target battery from the first moment to the current moment and the rated capacity of the target battery by the estimation device of the state of charge of the battery. Specifically, the estimation device of the state of charge of the battery integrates a first preset battery current from the first moment to the current moment to obtain a change capacity of the target battery from the first moment to the current moment, wherein the first preset battery current is a charging/discharging current of the target battery from the first moment to the current moment; dividing the change capacity of the target battery from the first moment to the current moment by the rated capacity of the target battery to obtain the capacity change proportion of the target battery from the first moment to the current moment; subtracting the capacity change proportion of the target battery from the first moment to the current moment from the first state of charge value of the target battery at the current moment to obtain a state of charge value SOC (t) of the target battery at the current moment, wherein the formula is as follows:
SOC(t0) And the current value is a first state of charge value of the target battery at the current moment, I is the first preset current, and Q is the rated capacity of the target battery.
According to the method, a battery state of charge estimation device searches a relation mapping table according to the current battery temperature of a target battery and the first charge state value of the target battery to obtain the current battery internal resistance value of the target battery, obtains the voltages of two ends of the target battery at the current time, and determines the current open-circuit voltage of the target battery according to the current battery voltage of the target battery, the current battery internal resistance value and the current charge/discharge current; determining a first state of charge value of the target battery at the current moment according to the open-circuit voltage of the target battery at the current moment and a preset corresponding relation between the open-circuit voltage and the state of charge; and calculating to obtain the output state of charge value of the target battery at the current moment according to the first state of charge value of the target battery at the current moment, the change capacity of the target battery from the first moment to the current moment and the rated capacity of the target battery. According to the embodiment, the first state of charge value of the target battery at the current moment is corrected, and the accuracy of estimation of the output state of charge value of the target battery at the current moment is improved.
Based on the embodiments described above with reference to fig. 1 to 3, the present application may also correct the rated capacity of the target battery, so as to further improve the accuracy of the estimation of the output state of charge value of the target battery at the current time. Referring to fig. 4, fig. 4 is a schematic flow chart of another battery state of charge estimation method provided in the embodiment of the present application. As shown in fig. 4, the method for estimating the state of charge value of the battery further includes:
s400, calculating to obtain the corrected rated capacity of the target battery by the battery state-of-charge estimation device according to the difference between the first state-of-charge value of the target battery at the current moment and the initial state-of-charge value of the target battery and the accumulated capacity of the target battery from the initial moment to the current moment, and taking the corrected rated capacity as the rated capacity of the target battery at the next time interval at the current moment. Specifically, the initial time t of the target battery is obtained from the above step S10001Initial state of charge SOC (t)01) Noted SOC (0); the first state of charge SOC (t) of the target battery at the current time is obtained in the step S1020) Noted as SOC (1); step S103, calculating the initial time t of the target battery0The cumulative capacity Q (1) to the current time t is:
calculating the corrected rated capacity Q of the target batterycal(1) Comprises the following steps:
correcting the rated capacity Q of the target batterycal(1) As the rated capacity of the target battery for the next time interval at the present moment. Then, in the next time interval at the present moment, the battery soc estimation device calculates the soc value of the target battery in the next time interval at the present moment using the corrected rated capacity Q of the target battery while repeating the method steps described above with reference to fig. 1 to 3cal(1) Instead of the rated capacity Q of the target battery, expressed as:
in one possible embodiment, the taking the corrected rated capacity as the rated capacity of the target battery for the next time interval at the current time includes: and the estimation device of the state of charge determines that the difference value between the first state of charge value of the target battery at the current moment and the initial state of charge value of the target battery is greater than a second preset threshold value. Specifically, a first state of charge value of the target battery at the current time is recorded as SOC (1), an initial state of charge value of the target battery is recorded as SOC (0), and when a depth of discharge of the target battery meets a certain condition, that is, when a difference between SOC (1) and SOC (0) is greater than a second preset threshold, for example, 10%, a rated capacity of the target battery after being corrected is taken as a rated capacity of the target battery at a next time interval at the current time.
On the basis of step S400, the state of charge estimation device further processes the data of the rated capacity of the target battery, and the specific implementation steps further include:
s401, the estimation device of the state of charge acquires a plurality of first state of charge values of the target battery at a plurality of different moments, and respectively calculates a plurality of rated capacities of the target battery after correction according to a difference value between the plurality of first state of charge values and an initial state of charge value of the target battery, and a plurality of accumulated capacities of the target battery from the initial moment to the moment when the plurality of first state of charge values are respectively acquired. Specifically, step S401 may be understood as repeatedly performing step S400 to obtain a plurality of rated capacities of the target battery after being corrected, and a specific formula may be represented as:
wherein Qcal(n) is the rated capacity of the target battery after being corrected at the nth time, SOC (n) is a first state of charge value of the target battery at the nth time, SOC (0) is an initial state of charge value of the target battery, and Q (n) is the accumulated capacity of the target battery from the initial time to the moment when the first state of charge value SOC (n) is acquired.
S402, the estimation device of the battery state of charge acquires an average value of the plurality of rated capacities corrected by the target battery, and if the difference value between each of the plurality of rated capacities corrected by the target battery and the average value of the plurality of rated capacities corrected by the target battery is smaller than a first preset threshold value, the average value of the plurality of rated capacities corrected by the target battery is used as the rated capacity corrected by the target battery. Specifically, the estimation device of the state of charge of the battery obtains a plurality of rated capacities of the target batteries after being corrected through calculation in step S401 to obtain 3 corrected rated capacities Qcal(1)、Qcal(2) And Qcal(3) For example, an average Q of 3 corrected rated capacities is obtainedaveIf Q iscal(1) And the average value QaveDifference value of (Q)cal(2) And the average value QaveDifference of (a) and Qcal(3) And the average value QaveAre all smaller than the first preset threshold value, and the average value Q of rated capacityaveAs the corrected rated capacity of the target battery. Implementing the present embodiment, further charging the targetAnd carrying out averaging processing on the data of the rated capacity of the battery, comparing the difference value between each corrected rated capacity and the average value of the rated capacity with a first preset threshold value, further optimizing the corrected rated capacity of the target battery, and improving the accuracy of the estimation of the state of charge of the target battery.
An embodiment of the present application provides a device for estimating a state of charge of a battery, and referring to fig. 5, fig. 5 is the device for estimating a state of charge of a battery provided in the embodiment of the present application. As shown in fig. 5, the battery state of charge estimation device 50 includes:
the searching module 500 is configured to search a relation mapping table according to a battery temperature of a target battery at a current moment and a state of charge value of the target battery at a first moment to obtain a battery internal resistance value of the target battery at the current moment, where the relation mapping table includes a corresponding relation among the battery internal resistance value, the battery temperature, and the state of charge value of the target battery, and the first moment is a state of charge estimation moment at a first time interval from the current moment;
an obtaining module 501, configured to obtain voltages at two ends of the target battery at a current moment;
a determining module 502, configured to determine an open-circuit voltage of the target battery at the current moment according to a voltage across the target battery at the current moment, a battery internal resistance value at the current moment, and a charging/discharging current at the current moment;
the determining module 502 is further configured to determine a first state of charge value of the target battery at the current time according to the open-circuit voltage of the target battery at the current time and a preset corresponding relationship between the open-circuit voltage and the state of charge;
the calculating module 503 is configured to calculate an output state of charge value of the target battery at the current time according to the first state of charge value of the target battery at the current time, the change capacity of the target battery from the first time to the current time, and the rated capacity of the target battery.
In a possible implementation manner, the obtaining module 501 is further configured to obtain a voltage across the target battery at an initial time, and use the voltage across the target battery at the initial time as an open-circuit voltage of the target battery at the initial time; the initial time is the measurement time after the target battery is charged/discharged for the last time;
the determining module 502 is further configured to determine an initial state of charge value of the target battery according to the open-circuit voltage of the target battery at the initial time and the preset corresponding relationship between the open-circuit voltage and the state of charge, where the initial state of charge value is a fixed value.
Further, the calculating module 503 is further configured to calculate a corrected rated capacity of the target battery according to a difference between the first state of charge value of the target battery at the current time and the initial state of charge value of the target battery, and an accumulated capacity of the target battery from the initial time to the current time, and use the corrected rated capacity as a rated capacity of the target battery at a next time interval at the current time.
Optionally, the obtaining module 501 is further configured to obtain a plurality of first state of charge values of the target battery at a plurality of different times;
the calculating module 503 is further configured to calculate, respectively according to differences between the first state of charge values and the initial state of charge values of the target battery, and a plurality of accumulated capacities of the target battery from an initial time to times when the first state of charge values are respectively obtained, to obtain a plurality of rated capacities of the target battery after correction;
the obtaining module 501 is further configured to obtain an average value of the plurality of rated capacities after the target battery is modified, and if a difference between each of the plurality of rated capacities after the target battery is modified and the average value of the plurality of rated capacities after the target battery is modified is smaller than a first preset threshold, take the average value of the plurality of rated capacities after the target battery is modified as the rated capacity after the target battery is modified.
In a possible embodiment, the determining module 502 is further configured to determine that a difference between the first state of charge value of the target battery at the current time and the initial state of charge value of the target battery is greater than a second preset threshold.
In a possible implementation manner, the determining module 502 is further configured to determine that the state of the target battery meets a preset condition, where the preset condition is that a state of charge value of the target battery at a first time is in a first preset interval, and/or a charging/discharging current of the target battery at the current time is smaller than a third preset threshold.
Optionally, the calculating module 503 is further configured to integrate a first preset battery current from the first time to the current time to obtain a change capacity of the target battery generated from the first time to the current time, where the first preset battery current is a charging/discharging current of the target battery from the first time to the current time;
the calculating module 503 is further configured to divide a change capacity of the target battery from the first time to the current time by a rated capacity of the target battery, so as to obtain a capacity change ratio of the target battery from the first time to the current time;
the calculating module 503 is further configured to subtract the capacity change ratio of the target battery from the first time to the current time from the first state of charge value of the target battery at the current time to obtain the state of charge value of the target battery at the current time.
By implementing the embodiment, the first state of charge value of the target battery at the current moment is corrected, and the estimation accuracy of the output state of charge value of the target battery at the current moment is improved.
An electronic device is further provided in the embodiments of the present application, referring to fig. 6, and fig. 6 is an electronic device provided in the embodiments of the present application. As shown in fig. 6, the electronic device 60 comprises a processor 600 and a memory 601, wherein:
the processor 600 may be a Central Processing Unit (CPU), and may also be other general purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The memory 601 stores instructions, it is understood that the memory 601 stores a functional relationship between an open circuit voltage and a state of charge of the target battery and/or an initial state of charge value, etc., and the memory 601 may include a read only memory and a random access memory, for example, and provides instructions and data to the processor 601. A portion of the memory 601 may also include non-volatile random access memory. For example, the memory 601 may also store device type information.
The processor 600 is configured to execute the computer program stored in the memory to implement any one of the possible embodiments described above.
In a specific implementation, the electronic device may execute, through each built-in functional module, the implementation manners provided in the steps in fig. 1 to fig. 3, which may be specifically referred to the implementation manners provided in the steps in fig. 1 to fig. 3, and are not described herein again.
The present application provides a computer-readable storage medium having stored therein instructions, which when executed on a computer, cause the computer to perform any one of the possible embodiments described above.
It should be noted that the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the embodiments provided in the present application, it should be understood that the disclosed method, apparatus, and system may be implemented in other ways. The above-described embodiments are merely illustrative, for example, the division of the unit is only a logical functional division, and there may be other division ways in actual implementation, such as: multiple units or components may be combined, or may be integrated into another system, or some features may be omitted, or not implemented. In addition, the coupling, direct coupling or communication connection between the components shown or discussed may be through some interfaces, and the indirect coupling or communication connection between the devices or units may be electrical, mechanical or in other forms.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed on a plurality of network units; some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, all the functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may be separately regarded as one unit, or two or more units may be integrated into one unit; the integrated unit can be realized in a form of hardware, or in a form of hardware plus a software functional unit.
Those of ordinary skill in the art will understand that: all or part of the steps for implementing the method embodiments may be implemented by hardware related to program instructions, and the program may be stored in a computer readable storage medium, and when executed, the program performs the steps including the method embodiments; and the aforementioned storage medium includes: a mobile storage device, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
Alternatively, the integrated unit of the present invention may be stored in a computer-readable storage medium if it is implemented in the form of a software functional module and sold or used as a separate product. Based on such understanding, the technical solutions of the embodiments of the present invention may be essentially implemented or a part contributing to the prior art may be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the methods described in the embodiments of the present invention. And the aforementioned storage medium includes: a removable storage device, a ROM, a RAM, a magnetic or optical disk, or various other media that can store program code.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of the changes or substitutions within the technical scope of the present invention, and shall cover the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (9)
1. A method of estimating a state of charge of a battery, the method comprising:
according to the current battery temperature of a target battery and the state of charge value of the target battery at a first moment, searching a relation mapping table to obtain the current battery internal resistance value of the target battery, wherein the relation mapping table comprises the corresponding relation among the current battery internal resistance value, the battery temperature and the state of charge value of the target battery, and the first moment is the state of charge estimation moment which is away from the current moment by a first time interval;
obtaining the voltage of the target battery at two ends of the battery at the current moment, and determining the open-circuit voltage of the target battery at the current moment according to the voltage of the target battery at two ends of the battery at the current moment, the internal resistance value of the battery at the current moment and the charging/discharging current at the current moment;
determining a first state of charge value of the target battery at the current moment according to the open-circuit voltage of the target battery at the current moment and a preset corresponding relation between the open-circuit voltage and the state of charge;
calculating to obtain an output state of charge value of the target battery at the current moment according to the first state of charge value of the target battery at the current moment, the change capacity of the target battery from the first moment to the current moment and the rated capacity of the target battery;
dividing the accumulated capacity of the target battery from the initial time to the current time by the difference between the first state of charge value of the target battery at the current time and the initial state of charge value of the target battery to obtain the corrected rated capacity of the target battery, and taking the corrected rated capacity as the rated capacity of the target battery at the next time interval at the current time; the initial time is the measurement time after the target battery is charged/discharged for the last time;
and calculating to obtain the output state of charge value of the target battery at the next time interval at the current moment according to the output state of charge value of the target battery at the current moment, the change capacity of the target battery from the current moment to the next time interval at the current moment and the rated capacity of the target battery at the next time interval at the current moment.
2. The method of claim 1, wherein the step of finding the battery internal resistance value of the target battery at the current moment in the map according to the battery temperature of the target battery at the current moment and the state of charge value of the target battery at the first moment comprises:
acquiring voltages of two ends of the target battery at an initial moment, and taking the voltages of the two ends of the target battery at the initial moment as an open-circuit voltage of the target battery at the initial moment; the initial time is the measurement time after the target battery is charged/discharged for the last time;
and determining an initial state of charge value of the target battery according to the open-circuit voltage of the target battery at the initial moment and the corresponding relation between the preset open-circuit voltage and the preset state of charge, wherein the initial state of charge value is a fixed value.
3. The method of claim 1, further comprising:
acquiring a plurality of first state of charge values of the target battery at a plurality of different moments, and respectively calculating a plurality of rated capacities of the target battery after correction according to differences between the plurality of first state of charge values and an initial state of charge value of the target battery and a plurality of accumulated capacities of the target battery from the initial moment to the moments when the plurality of first state of charge values are respectively acquired;
and if the difference between the plurality of rated capacities corrected by the target battery and the average of the plurality of rated capacities corrected by the target battery is smaller than a first preset threshold, taking the average of the plurality of rated capacities corrected by the target battery as the rated capacity corrected by the target battery.
4. The method of claim 1, wherein said applying the modified rated capacity as the rated capacity of the target battery for a time interval next to the current time comprises:
and determining that the difference value between the first state of charge value of the target battery at the current moment and the initial state of charge value of the target battery is larger than a second preset threshold value.
5. The method of claim 1, wherein determining the first state of charge value for the target battery at the current time comprises:
determining that the state of the target battery meets a preset condition, wherein the preset condition is that the state of charge value of the target battery at a first moment is in a first preset interval, and/or the charge/discharge current of the target battery at the current moment is smaller than a third preset threshold.
6. The method of claim 1, wherein the determining the first state of charge value of the target battery at the current time, the change capacity of the target battery from the first time to the current time, and the rated capacity of the target battery comprises:
integrating a first preset battery current from the first moment to the current moment to obtain the change capacity of the target battery from the first moment to the current moment, wherein the first preset battery current is the charge/discharge current of the target battery from the first moment to the current moment;
dividing the change capacity of the target battery from the first moment to the current moment by the rated capacity of the target battery to obtain the capacity change proportion of the target battery from the first moment to the current moment;
and subtracting the capacity change proportion of the target battery from the first moment to the current moment from the first state of charge value of the target battery at the current moment to obtain the state of charge value of the target battery at the current moment.
7. An estimation device of a state of charge of a battery, the estimation device comprising:
the system comprises a searching module, a relation mapping table and a control module, wherein the searching module is used for searching a battery internal resistance value of a target battery at the current moment in the relation mapping table according to the battery temperature of the target battery at the current moment and the state of charge value of the target battery at a first moment, the relation mapping table comprises the corresponding relation among the battery internal resistance value, the battery temperature and the state of charge value of the target battery, and the first moment is a state of charge estimation moment which is a first time interval away from the current moment;
the acquisition module is used for acquiring the voltage of the two ends of the target battery at the current moment;
the determining module is used for determining the open-circuit voltage of the target battery at the current moment according to the voltage of the two ends of the target battery at the current moment, the internal resistance value of the battery at the current moment and the charging/discharging current at the current moment;
the determining module is further configured to determine a first state of charge value of the target battery at the current moment according to the open-circuit voltage of the target battery at the current moment and a preset corresponding relationship between the open-circuit voltage and the state of charge;
the calculation module is used for calculating to obtain an output state of charge value of the target battery at the current moment according to the first state of charge value of the target battery at the current moment, the change capacity of the target battery from the first moment to the current moment and the rated capacity of the target battery;
the calculation module is further configured to divide the accumulated capacity of the target battery from an initial time to a current time by a difference between a first state of charge value of the target battery at the current time and the initial state of charge value of the target battery to obtain a corrected rated capacity of the target battery; the initial time is the measurement time after the target battery is charged/discharged for the last time;
the determining module is further configured to use the corrected rated capacity as a rated capacity of the target battery at a next time interval at the current moment;
the calculation module is further configured to calculate an output state of charge value of the target battery at the current time and the next time interval according to the output state of charge value of the target battery at the current time, the change capacity of the target battery from the current time to the next time interval at the current time, and the rated capacity of the target battery at the next time interval at the current time.
8. An electronic device, characterized in that the electronic device comprises a processor and a memory, wherein the processor is configured to execute a computer program stored in the memory to implement the steps of the method according to any one of claims 1 to 6.
9. A computer-readable storage medium having stored therein instructions which, when run on a computer, cause the computer to perform the steps of the method according to any one of claims 1 to 6.
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| CN113466717A (en) * | 2021-06-25 | 2021-10-01 | 深圳移航通信技术有限公司 | Method and apparatus for estimating state of charge of battery |
| CN113687248B (en) * | 2021-08-27 | 2024-03-22 | Oppo广东移动通信有限公司 | Battery capacity determining method and device, electronic equipment and storage medium |
| CN113933729A (en) * | 2021-09-30 | 2022-01-14 | 蜂巢能源科技有限公司 | Battery state of charge processing method and device, vehicle and battery management system |
| CN115113070A (en) * | 2021-12-24 | 2022-09-27 | 长城汽车股份有限公司 | Estimation method of battery SOC and related device |
| CN115469239B (en) * | 2022-06-29 | 2023-09-08 | 四川新能源汽车创新中心有限公司 | Method and device for evaluating charge state consistency of battery system and electronic equipment |
| CN114859250B (en) * | 2022-07-07 | 2022-09-30 | 杭州华塑科技股份有限公司 | Method and device for determining state of charge information of battery and electronic equipment |
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