CN116184236B

CN116184236B - Battery calibration method, battery calibration device, electronic equipment and storage medium

Info

Publication number: CN116184236B
Application number: CN202310461166.2A
Authority: CN
Inventors: 吴凯; 何斌斌; 王茂旭; 李洪雷; 孙昊
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2023-04-26
Filing date: 2023-04-26
Publication date: 2023-08-04
Anticipated expiration: 2043-04-26
Also published as: CN116184236A

Abstract

The application discloses a battery calibration method, a battery calibration device, electronic equipment and a storage medium. The method comprises the following steps: controlling the voltage of the battery to reach an initial cut-off voltage; under the condition that the voltage of the battery reaches the initial cut-off voltage, controlling the battery to sequentially enter a plurality of constant current testing phases, wherein each constant current testing phase comprises: the constant-current working sub-stage and the standing sub-stage are shorter in duration than the standing sub-stage, and the duration of the standing sub-stage does not exceed the preset duration; and calibrating to obtain an SOC-OCV curve of the battery according to the test data of the battery in a plurality of constant current test stages and a preset equivalent circuit model. Through this application scheme, can mark out the SOC-OCV curve of battery high accuracy fast, help promoting BMS to battery SOC's estimation accuracy.

Description

Battery calibration method, battery calibration device, electronic equipment and storage medium

Technical Field

The application belongs to the technical field of testing, and particularly relates to a battery calibration method, a battery calibration device, electronic equipment and a computer readable storage medium.

Background

The state of charge (SOC) of a battery is an important indicator of the battery, which indicates the ratio of the amount of power actually provided by the battery in the current state to the amount of power provided by the battery when the battery is fully charged. However, the SOC of the battery cannot be obtained by direct measurement and can be estimated only by a certain method.

Generally, there are two methods for estimating the SOC of the battery, respectively: open circuit voltage method and ampere-hour integration method. The open circuit voltage method is to measure an open circuit voltage (open circuit voltage, OCV) of a current battery and determine an SOC of the current battery from a correspondence relationship between the OCV and the SOC. When estimating the SOC using the open circuit voltage method, the accuracy of the estimation result depends on the accuracy of the SOC-OCV curve.

From this, it follows that the SOC-OCV curve is a basic parameter that often needs to be measured multiple times during the battery life cycle. However, the conventional calibration method requires a lot of time to obtain a relatively accurate SOC-OCV curve, which is difficult to perform during the service of the battery. This results in a large deviation of the SOC-OCV curve stored by the battery management system (Battery Management System, BMS) from the actual SOC-OCV curve after battery aging, which in turn results in a decrease in accuracy of estimation of the SOC by the BMS.

Disclosure of Invention

The application provides a battery calibration method, a battery calibration device, electronic equipment and a computer readable storage medium, which can quickly calibrate out an SOC-OCV curve of high precision of a battery and help to improve the estimation accuracy of BMS to the SOC of the battery.

In a first aspect, the present application provides a battery calibration method, including:

controlling the voltage of the battery to reach an initial cut-off voltage;

under the condition that the voltage of the battery reaches the initial cut-off voltage, controlling the battery to sequentially enter a plurality of constant current testing phases, wherein each constant current testing phase comprises: the constant-current working sub-stage and the standing sub-stage are shorter in duration than the standing sub-stage, and the duration of the standing sub-stage does not exceed the preset duration;

and calibrating to obtain an SOC-OCV curve of the battery according to the test data of the battery in a plurality of constant current test stages and a preset equivalent circuit model.

In a second aspect, the present application provides a battery calibration device comprising:

the first control module is used for controlling the voltage of the battery to reach the initial cut-off voltage;

the second control module is used for controlling the battery to sequentially enter a plurality of constant current test stages under the condition that the voltage of the battery reaches an initial cut-off voltage, wherein each constant current test stage comprises: the constant-current working sub-stage and the standing sub-stage are shorter in duration than the standing sub-stage, and the duration of the standing sub-stage does not exceed the preset duration;

And the calibration module is used for calibrating and obtaining the SOC-OCV curve of the battery according to the test data of the battery in a plurality of constant current test stages and a preset equivalent circuit model.

In a third aspect, the present application provides an electronic device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, the processor implementing the steps of the method of the first aspect when executing the computer program.

In a fourth aspect, the present application provides a computer readable storage medium storing a computer program which, when executed by a processor, performs the steps of the method of the first aspect described above.

In a fifth aspect, the present application provides a computer program product comprising a computer program which, when executed by one or more processors, implements the steps of the method of the first aspect described above.

Compared with the prior art, the beneficial effects that this application exists are: in order to reduce the test time required for calibrating the SOC-OCV curve, the application introduces an equivalent circuit model of the battery in the calibration process. It can be understood that the equivalent circuit model can simulate the charge-discharge dynamic process of the battery and provide various internal parameters of the battery in any state. Based on the above, when the electronic device tests the battery to collect test data of the battery, the battery is only required to stand for a short period of time in each constant current test stage; when the calibration is carried out based on the test data, the electronic equipment can carry out OCV calculation on the test data of the battery in each constant current test stage based on the equivalent circuit model, and an SOC-OCV curve close to a true value is obtained through an equivalent circuit strategy. Therefore, the electronic equipment can quickly calibrate the SOC-OCV curve of the battery with high precision, and helps to improve the estimation accuracy of the BMS on the battery SOC.

It will be appreciated that the advantages of the second to fifth aspects may be found in the relevant description of the first aspect, and are not described here again.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following description will briefly introduce the drawings that are needed in the embodiments or the description of the prior art, it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is an implementation flow diagram of a battery calibration method provided by an embodiment of the present application;

FIG. 2 is a schematic diagram of a Thevenin equivalent circuit model provided in an embodiment of the present application;

FIG. 3 is an exemplary graph of a discharge test curve provided by an embodiment of the present application;

FIG. 4 is a graph comparing effects provided by embodiments of the present application;

FIG. 5 is a block diagram of a battery calibration device according to an embodiment of the present application;

fig. 6 is a schematic structural diagram of an electronic device according to an embodiment of the present application.

Detailed Description

Embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical solutions of the present application, and thus are only examples, and are not intended to limit the scope of protection of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having" and any variations thereof in the description and claims of the present application and in the description of the figures above are intended to cover non-exclusive inclusions.

In the description of the embodiments of the present application, the technical terms "first," "second," etc. are used merely to distinguish between different objects and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, a particular order or a primary or secondary relationship.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

In the description of the embodiments of the present application, the term "and/or" is merely an association relationship describing an association object, which means that three relationships may exist, for example, a and/or B may mean: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.

In the description of the embodiments of the present application, the term "plurality" refers to two or more (including two) unless specifically defined otherwise.

Currently, the more widely used batteries are. The device can be applied to energy storage power supply systems such as hydraulic power, firepower, wind power and solar power stations, electric vehicles such as electric bicycles, electric motorcycles and electric automobiles, and even military equipment, aerospace and other fields. With the continuous expansion of the battery application field, the market demand thereof is also continuously expanding.

The SOC of the battery represents the current available power of the battery, and is an important index of the battery. Generally, there are two methods for identifying the SOC of a battery, respectively: open circuit voltage method and ampere-hour integration method. The open circuit voltage method is to measure the OCV of the current battery and determine the SOC of the current battery by the correspondence between the OCV and the SOC.

Since the BMS generally needs to determine a safe charge and discharge manner of the battery according to the SOC of the battery, optimize output efficiency of the battery pack, etc., a high-precision SOC is very important for the BMS, which can greatly improve the accuracy and effectiveness of BMS instructions. And when calculating the SOC using the open circuit voltage method, the accuracy of the calculation result thereof depends on the accuracy of the SOC-OCV curve.

The current calibration methods of the SOC-OCV curve mainly comprise two types: one type is to measure the OCV after standing for a long time (typically several hours) at a plurality of SOC points, and thus calibrate the SOC-OCV curve of the battery. The other type is to measure a static end-to-end voltage curve for a certain time at a plurality of SOC points, extrapolate to a certain moment (usually after a plurality of hours) after fitting by using a polynomial, so as to obtain an extrapolated stable end-to-end voltage, and calibrate the SOC-OCV curve.

For the first type of method set forth above, the resulting OCV curve is a true OCV curve. For each SOC point, the method requires a long rest time, typically 1-5 hours, due to: the longer the rest time, the closer the final resulting SOC-OCV curve is to the true value. Thus, if this method is used to obtain an SOC-OCV curve with a number of SOC points of 100, the required time will reach 100-500 hours.

For the second type of method set forth above, the resulting OCV curve is an extrapolated curve. The rest time required for the method is reduced for each SOC point, typically 0.5-2 hours. However, the method of extrapolation calculation is used, so that the final speculation of the obtained SOC-OCV curve has two defects:

the first type of defect is systematic offset. Compared with the SOC-OCV curve obtained by the first type of method, the SOC-OCV curve obtained by the method has systematic deviation, and the deviation is usually about 10-100 mV.

The second type of defect is a shape defect of the SOC-OCV curve. Because the OCV of each SOC point is independently fitted, certain fluctuation and error exist in each fitting process, and the instability of the fitting function is added, the obtained SOC-OCV curve has abnormal fluctuation and monotonicity change at certain parts.

The defects in the two aspects lead to lower accuracy of the SOC-OCV curve obtained by the second type of method, and limit the application scene of the SOC-OCV curve. In addition, if the method is adopted to obtain an SOC-OCV curve with the number of SOC points being 100, the time required for obtaining the SOC-OCV curve still reaches 50-200 hours.

From this, it is known that, after the battery is in service and aged, the SOC-OCV curve stored in the BMS has a larger deviation from the actual SOC-OCV curve, and the existing SOC-OCV calibration method is difficult to achieve high-precision calibration of the SOC-OCV curve in a shorter time, which may result in a decrease in accuracy of estimation of the SOC by the BMS.

Based on the above consideration, the embodiment of the application provides a battery calibration method, which realizes calibration of an SOC-OCV curve by introducing an equivalent circuit model. The equivalent circuit model can simulate the charge-discharge dynamic process of the battery and provide various internal parameters of the battery in any state, so that when the electronic equipment tests the battery to acquire test data of the battery, the battery is only required to stand for a short period of time in each constant current test stage; when the calibration is carried out based on the test data, the electronic equipment can carry out OCV calculation on the test data of the battery in each constant current test stage based on the equivalent circuit model, and an SOC-OCV curve close to a true value is obtained through an equivalent circuit strategy.

It is understood that the battery disclosed in the embodiments of the present application may be applied to an electric device. By way of example only, the powered device may be a cell phone, tablet, notebook computer, electric toy, electric tool, battery car, electric car, ship or spacecraft, etc., and the embodiments of the present application do not limit the specific type of powered device.

In order to illustrate the technical solutions proposed in the embodiments of the present application, the following description is made by specific embodiments.

The following describes a battery calibration method provided in the embodiment of the present application. Referring to fig. 1, the battery calibration method in the embodiment of the present application includes:

step 101, controlling the voltage of the battery to reach the initial cut-off voltage.

The initial cutoff voltage refers to the voltage at which the battery is expected to be prior to testing the battery.

Generally, the SOC-OCV curve of a battery can be subdivided into a charge SOC-OCV curve and a discharge SOC-OCV curve, which may be slightly different. Specifically, the charge SOC-OCV curve is an SOC-OCV curve obtained by calibration based on a charging process of the battery, and the discharge SOC-OCV curve is an SOC-OCV curve obtained by calibration based on a discharging process of the battery.

Therefore, in the practical application scenario, if the SOC of the battery in the discharging working state needs to be accurately estimated, the dependable SOC-OCV curve is specifically a discharging SOC-OCV curve, and if the SOC of the battery in the charging working state needs to be accurately estimated, the dependable SOC-OCV curve is specifically a charging SOC-OCV curve.

Therefore, in order to improve the test accuracy and the comprehensiveness, different test modes can be corresponding to different starting cut-off voltages. Wherein, the test mode of battery includes: a charge test mode and a discharge test mode. It will be appreciated that the charge test mode refers to a subsequent battery-based charging process for testing; similarly, discharge test mode refers to a subsequent battery-based discharge process for testing.

Specifically, the user can directly input the initial cut-off voltage of the test to the electronic equipment, so that the electronic equipment can judge the test mode of the battery according to the received value of the initial cut-off voltage and perform subsequent test operation; or the electronic equipment can also determine the test mode to be adopted for the battery at this time, then control the voltage of the battery to reach the initial cut-off voltage corresponding to the test mode, and perform subsequent test operation.

In some embodiments, the user may input, to the electronic device, a test mode to be adopted for the battery according to a test requirement of the user. For example, if the user focuses on the SOC of a certain battery during discharging, when testing the certain battery, the user may directly select the current test mode on the electronic device as follows: discharge test mode.

In other embodiments, the electronic device may also determine the test mode of the battery according to the application scenario of the battery. The application scene is used for indicating the main working state of the battery; that is, the application scenario may be used to indicate the operating state of the battery when an estimation of SOC is required. After determining the application scene of the battery, the electronic device can determine the test mode of the battery according to the application scene.

It can be understood that if the application scenario of the battery indicates that the main operation state of the battery is the charging operation state, the test mode of the battery can be correspondingly determined as the charging test mode; similarly, if the application scenario of the battery indicates that the main operation state of the battery is a discharge operation state, the test mode of the battery may be correspondingly determined as a discharge test mode.

In some examples, when the application scenario of the battery is an electric car, the application scenario indicates that the main operating state of the battery is a discharging operating state, for the following reasons: an electric automobile usually needs to display the SOC of a battery of the electric automobile to be referred to by an automobile owner in the driving process, and the driving process is actually a discharging process.

In other examples, when the application scenario of the battery is the energy storage bin, the application scenario indicates that the main working state of the battery is the charging working state, which is because: the energy storage bin needs to display the SOC of the battery to a user for reference in the energy storage process of the battery, and the energy storage process is actually a charging process.

It can be understood that, in the charging test mode, the test is performed based on the charging process of the battery, and the charging process requires the battery to be charged from a low power to a high power, so the starting cut-off voltage corresponding to the charging test mode is specifically the discharging cut-off voltage; that is, when the test mode of the battery is the charge test mode, the electronic device may control the battery to discharge at normal temperature until the voltage of the battery is less than or equal to the discharge cutoff voltage, thereby laying a foundation for the subsequent test based on the charge process.

Similarly, since the test is based on the discharging process of the battery in the discharging test mode, which requires the battery to be discharged from a high power to a low power, the starting cutoff voltage corresponding to the discharging test mode is specifically the charging cutoff voltage; that is, when the test mode of the battery is the discharge test mode, the electronic device may control the battery to charge at normal temperature until the voltage of the battery is greater than or equal to the charge cutoff voltage, thereby laying a foundation for the subsequent test based on the discharge process.

Further, the electronic device can control the battery to charge and discharge with a smaller constant current, so that the voltage of the battery can reach the initial cut-off voltage corresponding to the current test mode. The reason why the charge and discharge are performed with a small constant current is that: if the current is large, the temperature of the battery may rise, thereby affecting the performance of the battery, and the voltage of the battery may not actually reach the initial cut-off voltage corresponding to the current test mode. For example only, the constant current may be specifically less than 0.1C; when the test mode is a discharge test mode, the electronic equipment controls the battery to charge to a charge cut-off voltage with the constant current, and correspondingly, the C represents a standard capacity charging current; when the test mode is a charging test mode, the electronic device controls the battery to discharge to a discharge cut-off voltage at the constant current, and correspondingly, the C represents a standard capacity discharge current.

And 102, under the condition that the voltage of the battery reaches the initial cut-off voltage, controlling the battery to sequentially enter a plurality of constant current test stages.

After the voltage of the battery reaches the initial cutoff voltage, the electronic device may first rest the battery for a period of time, e.g., more than five minutes, to ensure accuracy of subsequent testing. After standing, the electronic device can start testing the battery, specifically: and controlling the battery to sequentially enter a plurality of constant current testing stages until the testing is finished. After the test is completed, the electronic device may also rest the battery for an additional period of time, e.g., more than five minutes.

Wherein each constant current test phase comprises: constant current working sub-stage and standing sub-stage.

It can be understood that the battery can work based on constant current in the constant current working sub-stage, and the working state is determined by the test mode, specifically: when the test mode is a discharge test mode, the battery discharges with constant current in the constant current working sub-stage; when the test mode is a charging test mode, the battery is charged with constant current in the constant current working sub-stage.

It will be appreciated that the battery does not perform any work (i.e., does not charge or discharge) during the rest sub-phase.

It should be noted that the duration of the constant current working sub-phase is shorter than the duration of the rest sub-phase, and the duration of the rest sub-phase is shorter, generally not longer than the preset duration. For example only, the preset duration may be 30 minutes.

And step 103, calibrating and obtaining an SOC-OCV curve of the battery according to test data of the battery in a plurality of constant current test stages and a preset equivalent circuit model.

In the testing process of the battery, various parameters of the battery can be read through the sensor, so that testing data of the battery, namely testing data of the battery in a plurality of constant current testing stages, can be obtained. For example only, the test data includes, but is not limited to, voltage data, current data, and a collection time corresponding to each data. It can be understood that the electric quantity of the battery is changed in a small extent in each constant current test stage, so that the battery is in a relatively stable SOC state after each constant current test stage; that is, each constant current test phase actually corresponds to one SOC point. Based on the above, the electronic device can calculate the corresponding SOC data of the battery in each constant current test stage according to the test data of the battery in each constant current test stage.

Based on this, in order to obtain OCV data corresponding to each SOC data of the battery, the embodiment of the present application introduces an equivalent circuit model of the battery. The equivalent circuit model may be used to describe internal resistance and polarization state inside the battery. The equivalent circuit model can simulate the charge-discharge dynamic process of the battery and provide various internal parameters of the battery in any state, including OCV data. In fact, the equivalent circuit model is introduced, so that the standing time after each constant current working sub-stage is shortened in the test process; that is, the shorter duration resting sub-stage proposed by the embodiments of the present application depends on the application of the equivalent circuit model.

In order to prevent the equivalent circuit model from deviating from the actual situation of the battery too much, the electronic device can comprehensively consider the test data of the battery in a plurality of constant current test stages and the equivalent circuit model, calculate the OCV data corresponding to the battery in each constant current test stage, that is, calculate the OCV data corresponding to each SOC data of the battery.

By way of example only, equivalent circuit models include, but are not limited to, the rint equivalent circuit model, the dyvalan equivalent circuit-based further optimized model, and the GNL model, etc., and are not described in detail herein.

In some embodiments, in order to reduce the influence of the battery temperature change on the test data during the test, and improve the accuracy of the SOC-OCV curve obtained by final calibration, the operation of controlling the battery to sequentially enter a plurality of constant current test phases in step 102 may include:

a1, controlling the battery to sequentially enter a plurality of first constant current testing stages until the voltage of the battery reaches a first preset voltage.

Wherein each first constant current test phase comprises: the first constant current working sub-stage and the standing sub-stage, and the first constant current working sub-stage is before the standing sub-stage. Since the foregoing has described that the operating state of the battery in this sub-stage is determined by the test mode, the electronic device will first control the battery to operate at a constant current in the operating state corresponding to the test mode, and then rest the battery, so as to cycle back and forth until the voltage of the battery reaches the first preset voltage.

Specifically, the electronic device may control the battery to operate at the same constant current in each of the first constant current operation sub-stages. In this case, the electronic device may first control the battery to operate at a first preset current constant current for a first preset period of time; then, standing the battery based on a preset standing time period; repeating the above process until the voltage of the battery reaches the first preset voltage.

Taking the test mode as a charging test mode as an example, the electronic device can control the battery to charge for a first preset time period with a first preset current constant current, then rest the battery for a preset rest time period, and repeat the above processes until the voltage of the battery reaches a first preset voltage.

Taking the test mode as a discharge test mode as an example, the electronic device can control the battery to discharge at a constant current for a first preset time period with a first preset current, then rest the battery for a preset rest time period, and repeat the above processes until the voltage of the battery reaches a first preset voltage.

A2, under the condition that the voltage of the battery reaches a first preset voltage, controlling the battery to sequentially enter a plurality of second constant current testing stages until the voltage of the battery reaches a second preset voltage;

similar to the first constant current test phase, each second constant current test phase comprises: the second constant current working sub-stage and the standing sub-stage, and the second constant current working sub-stage is before the standing sub-stage. Since the working state of the battery in the sub-stage is determined by the test mode as described above, the electronic device will control the battery to work with a constant current in the working state corresponding to the test mode, and then rest the battery, so as to cycle back and forth until the voltage of the battery reaches the second preset voltage.

Specifically, the electronic device may control the battery to operate at the same constant current in each second constant current operation sub-stage. In this case, the electronic device may first control the battery to operate at a second preset current constant current for a second preset period of time; then, standing the battery based on a preset standing time period; repeating the above processes until the voltage of the battery reaches a second preset voltage; so far, the test is ended.

Taking the test mode as a charging test mode as an example, the electronic device can firstly control the battery to charge for a second preset time period with a second preset current constant current, then rest the battery for a preset rest time period, and repeat the above processes until the voltage of the battery reaches a second preset voltage. So far, the test is ended.

Taking the test mode as a discharge test mode as an example, the electronic device can control the battery to discharge at a constant current for a second preset time period with a second preset current, then rest the battery for a preset rest time period, and repeat the above processes until the voltage of the battery reaches a second preset voltage. So far, the test is ended.

It should be noted that the first preset voltages corresponding to different test modes are also different; similarly, the second preset voltages corresponding to the different test modes are also different. And the first preset voltages corresponding to the same test mode may be the same or different. The embodiment of the application does not limit the first preset voltage and the second preset voltage.

For example only, in the case where the test mode is the charge test mode, the first preset voltage may be 3.65V, and the second preset voltage may be 3.65V; in the case that the test mode is the discharge test mode, the first preset voltage may be 3V, and the second preset voltage may be 2.5V. The electronic device may set the first preset voltage and the second preset voltage of the different types of batteries in different test modes according to actual situations, which will not be described herein.

It can be understood that the constant current working sub-stage included in the constant current test stage is actually divided into a first constant current working sub-stage and a second constant current working sub-stage. Whether the electronic equipment works in the first constant current working sub-stage or the second constant current working sub-stage, the electronic equipment works in constant current, and only the constant current corresponding to the first constant current working sub-stage (namely, the first preset current) is different from the constant current corresponding to the second constant current working sub-stage (namely, the second preset current), specifically: the first preset current is greater than the second preset current. The reason for this is that: when the battery is controlled to charge and discharge at a relatively large current, performance change of the battery can be caused due to temperature rise of the battery, and the battery still has residual charge and discharge practice; to solve this problem, it is necessary to control the battery to be charged and discharged with a relatively small current so that the battery can be charged and discharged in place. Accordingly, since the first preset current is greater than the second preset current, in order to enable relatively uniform arrangement of the SOC data obtained subsequently, the duration of the first constant current operation sub-stage may be set shorter than the duration of the second constant current operation sub-stage, that is, the first preset duration is shorter than the second preset duration.

For example only, the first preset current may have a value ranging from 0.5C to 1C and the second preset current may have a value ranging from 0.1C to 0.5C. When the test mode is a discharge test mode, the test is performed based on the discharge process of the battery, and the C represents the standard capacity discharge current; when the test mode is a charging test mode, the test is performed based on the charging process of the battery, and the C represents a standard capacity charging current.

For example only, the first predetermined duration may range from 10 seconds to 100 seconds and the second predetermined duration may range from 30 seconds to 300 seconds.

For easy understanding, the test preparation work and the test work in the battery calibration method according to the embodiments of the present application are fully described below based on different test modes. The test preparation corresponds to step 101 and the test preparation corresponds to step 102.

In the charge test mode:

1. the battery is controlled to discharge at constant current with current less than 0.1C at normal temperature until the voltage reaches the discharge cut-off voltage, and the battery is controlled to stop discharging and stand for a period of time, for example, more than 5 minutes.

2. And controlling the battery to charge for a first preset time period at a constant current of 0.5-1C. For example only, the first predetermined duration may range from 10 seconds to 100 seconds.

3. The battery is left standing for a period of time. By way of example only, the rest period may have a value in the range of 1 minute to 30 minutes.

4. And repeating the step 2 and the step 3 until the voltage of the battery is equal to or higher than the first preset voltage. For example only, the first preset voltage may be 3.65V.

5. And controlling the battery to charge for a second preset time period at the constant current of 0.1-0.5 ℃. For example only, the second predetermined time period may have a value in the range of 30 seconds to 300 seconds.

6. The battery is left standing for a period of time. The rest period is the same as that in step 3.

7. And (5) repeating the step (5) and the step (6) until the voltage of the battery is equal to or higher than a second preset voltage, and ending the test. For example only, the second preset voltage may also be 3.65V.

8. The cell is left for a period of time, for example, more than 5 minutes.

In discharge test mode:

1. the battery is controlled to charge at constant current at normal temperature and current less than 0.1C until the voltage reaches the charge cut-off voltage, and the battery is controlled to stop charging and stand for a period of time, for example, more than 5 minutes.

2. And controlling the battery to discharge at the constant current of 0.5-1C for a first preset time period. For example only, the first predetermined duration may range from 10 seconds to 100 seconds.

4. And repeating the step 2 and the step 3 until the voltage of the battery is equal to or lower than the first preset voltage. For example only, the first preset voltage may be 3V.

5. And controlling the battery to discharge at the constant current of 0.1-0.5 ℃ for a second preset time period. For example only, the second predetermined time period may have a value in the range of 30 seconds to 300 seconds.

7. And (5) repeating the step (5) and the step (6) until the voltage of the battery is equal to or lower than a second preset voltage, and ending the test. For example only, the second preset voltage may be 2.5V.

8. The cell is left for a period of time, for example, more than 5 minutes.

In some embodiments, the test data obtained by the electronic device may include: voltage data and current data obtained by continuously measuring the battery in the test process (namely in each constant current test stage), namely voltage data and current data at each moment; for convenience of description, the voltage data is referred to as test voltage data, and the current data is referred to as test current data. Based on the test data, step 103 may include:

B1, aiming at each constant current testing stage, determining SOC data corresponding to the battery in the constant current testing stage according to the testing current data of the constant current testing stage;

as described above, one constant current test phase may correspond to one SOC data. Based on the above, for any constant current test stage, the electronic device can identify test current data belonging to the constant current test stage from the test data; then, according to the test current data of the constant current test stage, calculating charge and discharge amount data (charge amount data corresponding to a charge test mode and discharge amount data corresponding to a discharge test mode) by an ampere-hour integration method; and finally, calculating the SOC data corresponding to the battery in the constant current test stage according to the charge and discharge amount data.

Of course, if the test data obtained by the electronic device includes the charge and discharge amount data of the battery in addition to the test voltage data and the test current data, the electronic device may also directly calculate the SOC data corresponding to the battery in each constant current test stage based on the charge and discharge data, which is not described herein.

And B2, fitting according to the test voltage data of the constant current test stage, the test current data of the constant current test stage and a preset equivalent circuit model to obtain OCV data corresponding to the battery in the constant current test stage.

Referring to fig. 2, fig. 2 shows a schematic diagram of the equivalent circuit model of the davin. Taking the Thevenin equivalent circuit model as an example, the following description refers to FIG. 2:

thevenin equivalent circuit model comprises 2 RC modules and R for describing ohmic impedance ₀ The method comprises the steps of carrying out a first treatment on the surface of the Uoc in fig. 2 represents OCV of the davin equivalent circuit model, UL represents terminal voltage of the davin equivalent circuit model, and I represents current flowing through the davin equivalent circuit model.

The equivalent circuit model may provide various internal parameters of the battery in any state, as described above. Specifically, for the Thevenin equivalent circuit model, the Thevenin equivalent circuit model is expressed by a differential equation, and an analytical solution is solved, and the analytical solution can quantitatively describe the dynamic response of the battery in any state, and the specific process is as follows:

wherein U is ₁ R represents ₁ Voltage (equivalent to C) ₁ Voltage of (2); u (U) ₂ R represents ₂ Voltage (equivalent to C) ₂ Voltage of (d) a voltage of (d).

Through the equivalent circuit model, the electronic equipment can simulate the testing process of the battery to obtain corresponding simulation data; after fitting the simulation data and the obtained test data (i.e. the real data of the battery), the values of the parameters (e.g. R, C and Uoc) in the davien equivalent circuit model can be obtained. Since the embodiment of the present application aims at calibrating the SOC-OCV curve, the real parameter of interest of the electronic device is only Uoc.

Based on the knowledge of the equivalent circuit model, the electronic equipment can determine simulation voltage data according to the test current data and the equivalent circuit model in a certain constant current test stage. By way of example only, the process may be specifically: and applying the test current data I (t) in the constant current test stage to the equivalent circuit model to obtain simulation voltage data UL_sim (t) output by the equivalent circuit model. Then, the electronic equipment can fit the simulation voltage data and the test voltage data in the constant current test stage through a preset fitting algorithm to obtain OCV data corresponding to the battery in the constant current test stage. By way of example only, the process may be embodied as; and performing nonlinear least square fitting on the test voltage data UL_real (t) and the simulation voltage data UL_sim (t) in the constant current test stage, so as to realize parameter identification of the equivalent circuit model, and obtaining each parameter of the equivalent circuit model, including R, C and Uoc, wherein the Uoc is OCV data corresponding to the battery in the constant current test stage.

And B3, calibrating an SOC-OCV curve of the battery according to the SOC data and the OCV data corresponding to each constant current test stage.

After the step B1 and the step B2, the electronic equipment can obtain SOC data and OCV data corresponding to each constant current test stage; that is, for the battery currently being tested, the electronic device may already obtain OCV data corresponding to each SOC data of the battery. The electronic equipment can calibrate the SOC-OCV curve of the battery according to the corresponding relation between the SOC data and the OCV data.

It can be understood that, for a constant current testing stage, since the constant current testing stage includes a constant current working sub-stage and a standing sub-stage, the battery only works with a constant current in the constant current working sub-stage, so that the voltage curve corresponding to the test voltage data in the constant current testing stage actually represents a pulse curve, and the current curve corresponding to the test current data in the constant current testing stage actually represents a pulse curve. Therefore, the electronic equipment can quickly identify the test current data and the test voltage data belonging to each constant current test stage.

Referring to fig. 3, an example of a discharge test curve is given in fig. 3. The test point serial numbers are used for representing the time sequences corresponding to the test data; the discharge test curve includes: a test voltage curve corresponding to the test voltage data in the discharge test mode, and a test current curve corresponding to the test current data in the discharge test mode.

In some embodiments, for the actual relaxation voltage curve of the battery, it can be considered as a linear superposition of the relaxation voltage curves of the RC modules of innumerable orders, where the relaxation voltage curve refers to: and the voltage is restored to the curve corresponding to the true voltage after standing for a period of time. That is, when the voltage of the battery after standing for a period of time is artificially specified as the OCV, the relaxation curve of this process can be practically decomposed into relaxation curves of several RC modules, and the coefficient of the relaxation curve of each RC module can be determined by the parameter identification of the equivalent circuit model shown above. However, in performing calibration of the SOC-OCV curve, the equivalent circuit model under consideration actually contains only RC-modules of several orders, e.g. the davin equivalent circuit model actually contains only RC-modules of two orders; that is, the calibration method proposed in the embodiment of the present application still has a certain limitation, and the duration of the rest sub-stage (i.e., the rest duration) cannot be too small. Based on this, the electronic device may determine the desired resting period of the battery first, and then determine the period of the resting sub-stage according to the desired resting period, where the period of the resting sub-stage and the desired resting period are in positive correlation.

For example only, a total duration of 300s for a constant current test phase, i.e., for that constant current test phase, 300s of test data may be obtained. The relaxation voltage curve of the battery in 300s can be formed by overlapping relaxation processes with time constants of 100s and 1000s, and the coefficient and the open circuit voltage of the battery can be determined through parameter identification. Wherein, the 300s test data includes all dynamic processes with time constant less than 10s and a small part of dynamic processes with time constant of 1000s, so that the longest time length of OCV identifiable by the 300s test data is 1000s×4=1.5 h. If the total duration of the constant current test phase is reduced, the signal content of the dynamic process with the time constant of 1000s is further reduced, so that the signal to noise ratio is too small to be recognized finally.

In some embodiments, the battery, while gradually aging from use to use, generally does not age too fast; that is, the performance of the battery is not generally greatly reduced in a short time. Based on this, it is necessary to calibrate the SOC-OCV curve of the battery only when there is a calibration demand for the battery. Specifically, when the electric automobile reaches the annual inspection time, the battery of the electric automobile is confirmed to have the calibration requirement; or, when the state of health (SOH) of the battery has fallen to a preset SOH value, confirming that the battery has a calibration requirement; or, when the battery is a brand new battery, the calibration requirement of the battery is confirmed, and the situation that the calibration requirement of the battery exists is not repeated here.

In order to facilitate understanding of the battery calibration method according to the embodiment of the present application, the following description is provided by way of specific examples:

when a certain lithium iron battery cell is normally in service and aged, the SOC-OCV curve of the lithium iron battery cell is greatly deviated from that before aging, and an original SOC-OCV curve is used in the BMS to estimate the SOC, so that the SOC-OCV curve needs to be recalibrated. In the existing battery calibration method, the OCV under a certain SOC is read after standing for 2-4 hours, and the process can consume a long time. When 70 OCVs are required to be measured continuously, the time spent reaches 140-280 hours, and the service of the iron-lithium battery cell is affected. Therefore, the battery calibration method provided by the embodiment of the application is used for calibrating the SOC-OCV curve.

In this example, only the discharge SOC estimation of the lithium iron cell is of interest, so that the test mode may be determined to be specifically a discharge test mode. First, the electronic device controls the constant current charging to 3.65V at normal temperature with a current of 0.04C, and stands for 5 minutes. Then, the electronic device controls the lithium iron battery cell to discharge for 60 seconds at a constant current of 1C, and to stand for 5 minutes, and the discharging and standing processes are repeated until the voltage of the lithium iron battery cell is equal to or lower than 3.0V. Then, the electronic device controls the lithium iron battery cell to discharge for 90 seconds at a constant current of 0.2 ℃ and to stand for 5 minutes, and the discharging and standing processes are repeated until the voltage of the lithium iron battery cell is equal to or lower than 2.5V, and the test is finished and the battery cell stands for 5 minutes. And finally, calibrating and obtaining the SOC-OCV curve of the lithium iron battery cell by the electronic equipment according to the test data of the lithium iron battery cell in the test process and a preset equivalent circuit model.

In order to verify the SOC-OCV curve obtained based on the battery calibration method provided in this embodiment, the same battery cell (i.e., the lithium iron battery cell) is kept stand for 2 hours under several SOCs and the OCV is measured, so as to obtain the corresponding relationship between the real SOC and the real OCV. The correspondence is plotted on the SOC-OCV curve obtained based on the battery calibration method proposed in the present embodiment, as shown in fig. 4. As can be seen from FIG. 4, the trend and the value are highly consistent, and the maximum deviation is only about 5 mV. Therefore, based on the battery calibration method provided by the embodiment of the application, a large amount of measurement time and measurement resources can be saved while the accuracy of the SOC-OCV curve is not excessively lost, so that the high-accuracy SOC-OCV curve of the battery in the using process can be updated.

From the above, in the embodiment of the present application, in order to reduce the test duration required for calibrating the SOC-OCV curve, the present application introduces an equivalent circuit model of the battery during the calibration process. It can be understood that the equivalent circuit model can simulate the charge-discharge dynamic process of the battery and provide various internal parameters of the battery in any state. Based on the above, when the electronic device tests the battery to collect test data of the battery, the battery is only required to stand for a short period of time in each constant current test stage; when the calibration is carried out based on the test data, the electronic equipment can carry out OCV calculation on the test data of the battery in each constant current test stage based on the equivalent circuit model, and an SOC-OCV curve close to a true value is obtained through an equivalent circuit strategy. Therefore, the electronic equipment can quickly calibrate the SOC-OCV curve of the battery with high precision, and helps to improve the estimation accuracy of the BMS on the battery SOC.

It should be understood that the sequence number of each step in the foregoing embodiment does not mean that the execution sequence of each process should be determined by the function and the internal logic of each process, and should not limit the implementation process of the embodiment of the present application in any way.

Corresponding to the battery calibration method provided above, the embodiment of the application also provides a battery calibration device. Referring to fig. 5, the battery calibration device 5 in the embodiment of the present application includes:

a first control module 501 for controlling the voltage of the battery to reach a starting cut-off voltage;

the second control module 502 is configured to control the battery to sequentially enter a plurality of constant current test phases when the voltage of the battery reaches an initial cutoff voltage, where each constant current test phase includes: the constant-current working sub-stage and the standing sub-stage are shorter in duration than the standing sub-stage, and the duration of the standing sub-stage does not exceed the preset duration;

and the calibration module 503 is configured to calibrate and obtain an SOC-OCV curve of the battery according to test data of the battery in a plurality of constant current test phases and a preset equivalent circuit model.

In some embodiments, the second control module 502 includes:

the first control unit is used for controlling the battery to sequentially enter a plurality of first constant current test stages until the voltage of the battery reaches a first preset voltage under the condition that the voltage of the battery reaches an initial cut-off voltage;

The second control unit is used for controlling the battery to sequentially enter a plurality of second constant current test stages until the voltage of the battery reaches a second preset voltage under the condition that the voltage of the battery reaches the first preset voltage;

wherein each first constant current test phase comprises: the first constant current working sub-stage and the standing sub-stage, and each second constant current testing stage comprises: the second constant current working sub-stage and the standing sub-stage, and the duration of the first constant current working sub-stage is shorter than that of the second constant current working sub-stage.

In some embodiments, the first control unit comprises:

the first control subunit is used for controlling the battery to work for a first preset time period with a first preset current constant current;

a first resting subunit for resting the battery based on a preset resting period;

the first control subunit and the first standing subunit are triggered to operate in sequence repeatedly until the voltage of the battery reaches a first preset voltage.

In some embodiments, the second control unit comprises:

the second control subunit is used for controlling the battery to work at a constant current of a second preset current for a second preset time period;

the second standing subunit is used for standing the battery based on a preset standing time period;

The second control subunit and the second standing subunit are triggered to operate in sequence repeatedly until the voltage of the battery reaches a second preset voltage.

In some embodiments, the test data comprises: test voltage data and test current data; the calibration module 503 includes:

the determining unit is used for determining SOC data corresponding to the battery in the constant current test stage according to the test voltage data and the test current data of the constant current test stage for each constant current test stage;

the fitting unit is used for fitting to obtain OCV data corresponding to the battery in the constant current test stage according to the test voltage data in the constant current test stage, the test current data in the constant current test stage and a preset equivalent circuit model;

and the calibration unit is used for calibrating the SOC-OCV curve of the battery according to the SOC data and the OCV data corresponding to each constant current test stage.

In some embodiments, the fitting unit comprises:

the determining subunit is used for determining simulation voltage data according to the test current data and the equivalent circuit model;

and the fitting subunit is used for fitting the simulation voltage data and the test voltage data through a preset fitting algorithm to obtain OCV data corresponding to the battery in the constant current test stage.

In some embodiments, the battery calibration device 5 further comprises:

the first determining module is used for determining a test mode of the battery according to the application scene of the battery;

accordingly, the first control module 501 is specifically configured to control the voltage of the battery to reach the initial cut-off voltage corresponding to the test mode.

In some embodiments, the battery calibration device 5 further comprises:

a second determining module for determining a desired rest period of the battery;

and the third determining module is used for determining the duration of the standing sub-stage according to the expected standing duration.

Corresponding to the battery calibration method provided above, the embodiment of the application also provides electronic equipment. Referring to fig. 6, the electronic device 6 in the embodiment of the present application includes: a memory 601, one or more processors 602 (only one shown in fig. 6) and computer programs stored on the memory 601 and executable on the processors. Wherein: the memory 601 is used for storing software programs and modules, and the processor 602 executes various functional applications and data processing by running the software programs and units stored in the memory 601 to acquire resources corresponding to the preset events. Specifically, the processor 602 implements the following steps by running the above-described computer program stored in the memory 601:

controlling the voltage of the battery to reach an initial cut-off voltage;

Assuming that the foregoing is a first possible embodiment, in a second possible embodiment provided by way of example of the first possible embodiment, the control unit sequentially enters a plurality of constant current test phases, including:

controlling the battery to sequentially enter a plurality of first constant current testing stages until the voltage of the battery reaches a first preset voltage;

under the condition that the voltage of the battery reaches a first preset voltage, controlling the battery to sequentially enter a plurality of second constant current testing stages until the voltage of the battery reaches a second preset voltage;

In a third possible implementation manner provided by the second possible implementation manner, the controlling the battery sequentially enters a plurality of first constant current test stages until the voltage of the battery reaches a first preset voltage includes:

controlling the battery to work for a first preset time period at a first preset current constant current;

standing the battery based on a preset standing time period;

Repeating the above process until the voltage of the battery reaches the first preset voltage.

In a fourth possible implementation manner provided by the second possible implementation manner, the controlling the battery sequentially enters a plurality of second constant current test stages until the voltage of the battery reaches a second preset voltage includes:

controlling the battery to work for a second preset time period at a second preset current constant current;

standing the battery based on a preset standing time period;

repeating the above process until the voltage of the battery reaches a second preset voltage.

In a fifth possible embodiment provided on the basis of the first possible embodiment described above, the test data includes: test voltage data and test current data; according to test data of the battery in a plurality of constant current test stages and a preset equivalent circuit model, calibrating to obtain an SOC-OCV curve of the battery, wherein the method comprises the following steps:

for each constant current testing stage, determining SOC data corresponding to the battery in the constant current testing stage according to the testing voltage data and the testing current data of the constant current testing stage;

fitting according to test voltage data in a constant current test stage, test current data in the constant current test stage and a preset equivalent circuit model to obtain OCV data corresponding to the battery in the constant current test stage;

And calibrating an SOC-OCV curve of the battery according to the SOC data and the OCV data corresponding to each constant current test stage.

In a sixth possible implementation manner provided by the fifth possible implementation manner as the basis, fitting to obtain OCV data corresponding to the battery in the constant current test stage according to the test voltage data in the constant current test stage, the test current data in the constant current test stage, and a preset equivalent circuit model includes:

determining simulation voltage data according to the test current data and the equivalent circuit model;

and fitting the simulation voltage data and the test voltage data through a preset fitting algorithm to obtain OCV data corresponding to the battery in the constant current test stage.

In a seventh possible implementation provided by the first possible implementation as a basis, before the voltage of the control battery reaches the initial cut-off voltage, the processor 602 further implements the following steps by running the above-mentioned computer program stored in the memory 601:

determining a test mode of the battery according to the application scene of the battery;

accordingly, controlling the voltage of the battery to reach the initial cutoff voltage includes:

the voltage of the battery is controlled to reach an initial cut-off voltage corresponding to the test mode.

In an eighth possible implementation provided on the basis of the first possible implementation, or the second possible implementation, or the third possible implementation, or the fourth possible implementation, or the fifth possible implementation, or the sixth possible implementation, or the seventh possible implementation, the processor 602 further implements the following steps by running the computer program stored in the memory 601:

determining a desired rest period of the battery;

and determining the duration of the standing sub-stage according to the expected standing duration.

It should be appreciated that in embodiments of the present application, the processor 602 may be a central processing unit (Central Processing Unit, CPU), which may also be other general purpose processors, digital signal processors (Digital Signal Processor, DSPs), application specific integrated circuits (Application Specific Integrated Circuit, ASICs), off-the-shelf programmable gate arrays (Field-Programmable Gate Array, FPGAs) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

Memory 601 may include read only memory and random access memory and provides instructions and data to processor 602. Some or all of the memory 601 may also include non-volatile random access memory. For example, the memory 601 may also store information of a device type.

It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-described division of the functional units and modules is illustrated, and in practical application, the above-described functional distribution may be performed by different functional units and modules according to needs, i.e. the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-described functions. The functional units and modules in the embodiment may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit, where the integrated units may be implemented in a form of hardware or a form of a software functional unit. In addition, specific names of the functional units and modules are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present application. The specific working process of the units and modules in the above system may refer to the corresponding process in the foregoing method embodiment, which is not described herein again.

In the foregoing embodiments, the descriptions of the embodiments are emphasized, and in part, not described or illustrated in any particular embodiment, reference is made to the related descriptions of other embodiments.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of external device software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

In the embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other manners. For example, the system embodiments described above are merely illustrative, e.g., the division of modules or units described above is merely a logical functional division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted, or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection via interfaces, devices or units, which may be in electrical, mechanical or other forms.

The units described above as separate components may or may not be physically separate, and components shown as units may or may not be physical units, may be located in one place, or may be distributed over a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

The integrated units described above, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the present application implements all or part of the flow of the method of the above-described embodiments, or may be implemented by a computer program to instruct associated hardware, where the computer program may be stored in a computer readable storage medium, where the computer program, when executed by a processor, may implement the steps of each of the method embodiments described above. The computer program comprises computer program code, and the computer program code can be in a source code form, an object code form, an executable file or some intermediate form and the like. The above computer readable storage medium may include: any entity or device capable of carrying the computer program code described above, a recording medium, a U disk, a removable hard disk, a magnetic disk, an optical disk, a computer readable Memory, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), an electrical carrier wave signal, a telecommunications signal, a software distribution medium, and so forth. It should be noted that the content of the computer readable storage medium described above may be appropriately increased or decreased according to the requirements of the jurisdiction's legislation and the patent practice, for example, in some jurisdictions, the computer readable storage medium does not include electrical carrier signals and telecommunication signals according to the legislation and the patent practice.

The above embodiments are only for illustrating the technical solution of the present application, and are not limiting thereof; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application.

Claims

1. A battery calibration method, comprising:

controlling the voltage of the battery to reach an initial cut-off voltage;

and under the condition that the voltage of the battery reaches the initial cut-off voltage, controlling the battery to sequentially enter a plurality of constant current testing phases, wherein each constant current testing phase comprises the following steps: the constant-current working sub-stage and the standing sub-stage, wherein the duration of the constant-current working sub-stage is shorter than that of the standing sub-stage, and the duration of the standing sub-stage does not exceed a preset duration;

calibrating and obtaining an SOC-OCV curve of the battery according to test data of the battery in the constant current test stages and a preset equivalent circuit model;

The control of the battery sequentially enters a plurality of constant current testing stages, including:

controlling the battery to sequentially enter a plurality of first constant current testing stages and a plurality of second constant current testing stages, wherein a first preset current is larger than a second preset current, the first preset current is the current of the battery when in constant current operation in the first constant current testing stage, and the second preset current is the current of the battery when in constant current operation in the second constant current testing stage;

wherein the test data comprises: test voltage data and test current data; in the SOC-OCV curve, for each constant current test stage, OCV data corresponding to the battery in the constant current test stage is obtained by the following steps:

determining simulation voltage data according to the test current data of the constant current test stage and the equivalent circuit model;

and fitting the simulation voltage data and the test voltage data of the constant current test stage through a preset fitting algorithm to obtain OCV data corresponding to the battery in the constant current test stage.

2. The method of calibrating a battery according to claim 1, wherein said controlling the battery to sequentially enter a plurality of constant current test phases comprises:

controlling the battery to sequentially enter a plurality of second constant current test stages under the condition that the voltage of the battery reaches the first preset voltage until the voltage of the battery reaches the second preset voltage;

wherein each of the first constant current test phases comprises: the first constant current working sub-stage and the standing sub-stage, and each second constant current testing stage comprises: the second constant current working sub-stage and the standing sub-stage, and the duration of the first constant current working sub-stage is shorter than that of the second constant current working sub-stage.

3. The method for calibrating a battery according to claim 2, wherein the controlling the battery to sequentially enter a plurality of first constant current test stages until the voltage of the battery reaches a first preset voltage comprises:

and controlling the battery to work for a first preset time period with a first preset current constant current, and standing the battery based on the preset standing time period until the voltage of the battery reaches the first preset voltage.

4. The method for calibrating a battery according to claim 2, wherein the controlling the battery to sequentially enter a plurality of second constant current test stages until the voltage of the battery reaches a second preset voltage comprises:

And controlling the battery to work for a second preset time period with a second preset current constant current, and standing the battery based on the preset standing time period until the voltage of the battery reaches the second preset voltage.

5. The battery calibration method according to claim 1, wherein the calibrating to obtain the SOC-OCV curve of the battery according to the test data of the battery in the plurality of constant current test phases and a preset equivalent circuit model includes:

for each constant current testing stage, determining SOC data corresponding to the battery in the constant current testing stage according to the testing current data of the constant current testing stage;

fitting according to the test voltage data of the constant current test stage, the test current data of the constant current test stage and a preset equivalent circuit model to obtain OCV data corresponding to the battery in the constant current test stage;

6. The battery calibration method of claim 1, wherein before the voltage of the control battery reaches an initial cutoff voltage, the battery calibration method further comprises:

the controlling the voltage of the battery to reach the initial cut-off voltage comprises:

and controlling the voltage of the battery to reach the initial cut-off voltage corresponding to the test mode.

7. The battery calibration method according to any one of claims 1 to 6, characterized in that the battery calibration method further comprises:

determining a desired resting period of the battery;

8. A battery calibration device, comprising:

the second control module is used for controlling the battery to sequentially enter a plurality of constant current test stages under the condition that the voltage of the battery reaches the initial cut-off voltage, wherein each constant current test stage comprises: the constant-current working sub-stage and the standing sub-stage, wherein the duration of the constant-current working sub-stage is shorter than that of the standing sub-stage, and the duration of the standing sub-stage does not exceed a preset duration;

the calibration module is used for calibrating and obtaining an SOC-OCV curve of the battery according to the test data of the battery in the constant current test stages and a preset equivalent circuit model;

The second control module is specifically configured to control the battery to sequentially enter a plurality of first constant current test phases and a plurality of second constant current test phases when the voltage of the battery reaches the initial cutoff voltage, where a first preset current is greater than a second preset current, the first preset current is a current when the battery works in a constant current in the first constant current test phase, and the second preset current is a current when the battery works in a constant current in the second constant current test phase;

9. An electronic device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the method of any one of claims 1 to 7 when the computer program is executed.

10. A computer readable storage medium storing a computer program, characterized in that the computer program when executed by a processor implements the method according to any one of claims 1 to 7.