CN114646892B - Method and device for obtaining SOC-OCV curve and lithium intercalation-OCV curve of secondary battery - Google Patents

Method and device for obtaining SOC-OCV curve and lithium intercalation-OCV curve of secondary battery Download PDF

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CN114646892B
CN114646892B CN202210541048.8A CN202210541048A CN114646892B CN 114646892 B CN114646892 B CN 114646892B CN 202210541048 A CN202210541048 A CN 202210541048A CN 114646892 B CN114646892 B CN 114646892B
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CN114646892A (en
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陈新虹
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Suzhou Yilai Kede Technology Co ltd
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    • G—PHYSICS
    • 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]
    • G01R31/396—Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
    • G—PHYSICS
    • 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]
    • G01R31/378—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC] specially adapted for the type of battery or accumulator
    • G—PHYSICS
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries

Abstract

The invention discloses a method and a device for acquiring a secondary battery SOC-OCV curve and a lithium intercalation amount-OCV curve, wherein the method for acquiring the secondary battery SOC-OCV curve comprises the following steps: acquiring multiple groups of discharge current and voltage data of the full battery based on the given discharge depth; drawing a discharge current-voltage curve based on the obtained multiple groups of discharge current and voltage data of the full battery; determining target voltage data based on the drawn discharge current-voltage curve; based on the given depth of discharge and the target voltage data, an SOC-OCV curve is obtained. According to the method, the open-circuit voltage OCV can be quickly and accurately determined only by drawing a plurality of groups of discharge current-voltage curves based on large discharge current and voltage data.

Description

Method and device for obtaining SOC-OCV curve and lithium intercalation-OCV curve of secondary battery
Technical Field
The invention relates to the field of secondary batteries, in particular to a method and a device for acquiring a secondary battery SOC-OCV curve and acquiring a lithium intercalation amount-OCV of a secondary battery electrode material.
Background
In the using process of the lithium ion battery, the SOC (state of charge) of the lithium ion battery is an important index, represents the percentage of the remaining available electric quantity of the battery to the total electric quantity, is one of the most important states in a battery management system, and provides important references for the functions of battery safety management, charge and discharge control, vehicle energy management and the like of the electric vehicle. Therefore, performing SOC estimation with high accuracy is a problem that all electric vehicle BMS software development must face. Accurate calibration of the battery SOC will affect the service life of the battery, as well as the dynamic and safety performance of the electric vehicle. At present, most of the SOC calibration of the whole vehicle is calibrated by combining an ampere-hour integration method with a voltage method, and a power battery manufacturer is required to provide an accurate SOC-OCV (system on chip-OCV) meter for charging and discharging before the calibration is carried out. The method for calibrating the SOC-OCV curve in the prior art has long calibration period, high difficulty in calibrating the SOC-OCV and large influence of large current relaxation in the calibration process.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention provides a method and a device for acquiring a secondary battery SOC-OCV curve and a secondary battery electrode material lithium intercalation amount-OCV curve.
In order to achieve the purpose, the invention adopts the technical scheme that:
in a first aspect, there is provided a method of acquiring a secondary battery SOC-OCV curve, comprising the steps of:
acquiring multiple groups of discharge current and voltage data of the full battery based on the given discharge depth;
drawing a discharge current-voltage curve based on the obtained multiple groups of discharge current and voltage data;
obtaining target voltage data based on the drawn discharge current-voltage curve;
based on the given depth of discharge and the target voltage data, an SOC-OCV curve is obtained.
In the present application, SOC is a State of Charge (State of Charge) of the battery, and OCV is an Open Circuit Voltage (Open Circuit Voltage) of the battery. Generally, according to the Tafel formula, when the current approaches 0, the internal resistance of the battery is basically unchanged, so the voltage of the battery at this time is the OCV of the battery. By the method, the measurement mode of long period and great difficulty in measuring the OCV of the battery at a small current (when the current approaches to 0) is avoided. And drawing a target discharge current-voltage curve based on a plurality of groups of large discharge current, composite Tafel linear stages and voltage data according to a linear fitting mode. And then, determining the area with basically unchanged internal resistance through the curve, thereby quickly and accurately determining the open-circuit voltage OCV data.
Further, wherein a plurality of sets of discharge current and voltage data of the full cell are acquired based on a given depth of discharge, comprising the steps of:
respectively obtaining discharge curves of the full battery under different discharge rates;
and acquiring multiple groups of discharge current and voltage data under a given discharge depth based on the obtained discharge curve.
In the application, the Discharge curve is a DOD-V curve, the DOD is Depth of Discharge (Depth of Discharge), the DOD-V is Depth of Discharge-voltage, the data of the Depth of Discharge and the voltage can be obtained through the Discharge curves under different Discharge multiplying powers, the data are data conventionally provided by battery manufacturers, and the data are very accurate to obtain. Of course, the above data can also be obtained by measuring with a test device at a plurality of different depths of discharge.
Further, wherein the target voltage data is determined based on the plotted discharge current-voltage curve, comprising the steps of:
extending the drawn discharge current-voltage curve to a position where the discharge current is less than or equal to 0.020C according to a curve extension trend to obtain a target curve;
obtaining target voltage data of corresponding positions of the target curve when the discharge current is less than or equal to 0.020C based on the target curve;
the target voltage data is the OCV of the full battery.
Specifically, the manner in which the curve extending tendency is extended may be a linear fit or other various manners. The target curve obtained by the above method can be used to obtain an OCV quickly without direct measurement by simply searching a voltage point at which the discharge current is 0.020C or less based on the target curve to obtain an equivalent usable target voltage (equivalent to an OCV). Of course, considering the influence of polarization, the optimum voltage point is when the discharge current is equal to 0C, and the resulting voltage is the most accurate OCV.
In a second aspect, there is provided a method of obtaining a lithium intercalation amount-OCV curve of a secondary battery electrode material, comprising:
acquiring a plurality of groups of discharge current and voltage data of the electrode material based on the given discharge depth;
drawing a discharge current-voltage curve based on the obtained multiple groups of discharge current and voltage data of the electrode material;
determining target voltage data based on the drawn discharge current-voltage curve;
obtaining an electrode material SOC-OCV curve based on the given discharge depth and the target voltage data;
based on the obtained electrode material SOC-OCV curve, an electrode material lithium intercalation amount-OCV curve is obtained.
As mentioned above, according to the Tafel formula, when the current approaches 0, the internal resistance of the battery is substantially unchanged, so the voltage of the battery at this time is the open-circuit OCV of the battery. By the method, the measurement mode of long period and great difficulty in measuring the OCV of the battery at a small current (when the current approaches to 0) is avoided. Only a plurality of groups of discharge current-voltage curves drawn by large discharge current and voltage data are needed, so that the open-circuit voltage OCV data can be quickly and accurately determined. And the amount of lithium insertion is converted from SOC in a known manner.
Further, wherein the step of obtaining multiple sets of discharge current and voltage data for the electrode material based on a given depth of discharge comprises the steps of:
respectively measuring discharge curves of the electrode material under different discharge multiplying powers;
based on the measured discharge curve, multiple sets of discharge current and voltage data at a given depth of discharge are obtained.
Similarly, the Discharge curve is a DOD-V curve, the DOD is the Depth of Discharge (Depth of Discharge), the DOD-V is the Depth of Discharge-voltage, the data of the Depth of Discharge and the voltage can be obtained through the Discharge curves under different Discharge multiplying powers, and the data are data conventionally provided by battery manufacturers and are very accurate to obtain. Of course, the data can also be obtained by direct measurement by the test equipment under a plurality of different discharge depths.
Further, the method for respectively measuring the discharge curves of the electrode material under different discharge rates comprises the following steps:
implanting a third electrode in the lithium battery;
connecting the third electrode with the positive electrode material or the negative electrode material:
and measuring the discharge curves of the anode material or the cathode material under different discharge multiplying powers.
The DOD-V curve of the measuring electrode can not be directly measured by connecting the anode and the cathode, the measuring electrode needs to be measured by implanting a third electrode, at the moment, the DOD-V curve of the corresponding full cell and the DOD-V curve of the anode (or the cathode) can be measured by simultaneously connecting the anode and the cathode, and the anode (or the cathode) and the third electrode, and the DOD-V curve of the cathode (or the anode) can be obtained by simple calculation.
Further, wherein the target voltage data is determined based on the plotted discharge current-voltage curve, comprising the steps of:
and extending the drawn discharge current-voltage curve to a position where the current is less than or equal to 0.020C according to the curve extension trend to obtain a target curve. The manner in which the curve extending tendency is extended may be a linear fit or other various manners.
And obtaining target voltage data of the corresponding position of the target curve when the current is less than or equal to 0.020C based on the target curve.
The target voltage data is the OCV of the electrode material.
As with the full cell, for the electrode material, the target curve obtained by the above method, based on which only the voltage point at which the discharge current is 0.02C or less needs to be found, the OCV can be obtained quickly without direct measurement in terms of obtaining a usable target voltage (equivalent to OCV) equally. Of course, considering the influence of polarization, the optimum voltage point is when the discharge current is equal to 0C, and the resulting voltage is the most accurate OCV.
Further, the method for obtaining the lithium intercalation amount-OCV curve of the electrode material comprises the following steps:
the chemical formula of the cathode material is Li x MO 2 Wherein M can be one or more of Ni or Co or Mn elements, and the stoichiometric ratio is 1, 0<x<1；
x satisfies the following formula:
Figure DEST_PATH_IMAGE001
wherein the content of the first and second substances,
Figure DEST_PATH_IMAGE002
is a DOD value;
Figure 933651DEST_PATH_IMAGE003
when SOC =100%, the positive electrode material is embedded correspondinglyThe amount of lithium;
Figure DEST_PATH_IMAGE004
SOC =0%, the amount of lithium insertion corresponding to the positive electrode material,
Figure 585212DEST_PATH_IMAGE004
=
Figure 161687DEST_PATH_IMAGE003
+ full cell capacity/theoretical capacity of the positive electrode material.
As for the state of the positive electrode material of the lithium battery, the positive electrode material molecule Li x MO 2 The change of the quantity of the middle Li electrons is inversely related to the SOC, namely the lithium insertion quantity is smaller when the SOC is larger, and the SOC can be converted into the lithium insertion quantity of the cathode material through the above formula. Further, when the SOC is changed from 0% to 100%, x is changed in a narrower interval. Through the mode, the positive electrode material lithium insertion amount-OCV curve can be obtained through the technical scheme of the application in a mode of directly measuring and obtaining the discharge current-voltage curve under the large current. And DOD-V curve data under different discharge rates can also be directly used, and the anode material lithium insertion amount-OCV curve is obtained through conversion by the technical scheme method of the application.
Further, the method for obtaining the lithium intercalation amount-OCV curve of the electrode material comprises the following steps:
the chemical formula of the cathode material is Li y C 6 Wherein 0 is<y<1；
y satisfies the following formula:
Figure 291317DEST_PATH_IMAGE005
wherein the content of the first and second substances,
Figure 105689DEST_PATH_IMAGE002
is a DOD value;
Figure DEST_PATH_IMAGE006
when SOC =100%, the intercalation amount corresponding to the negative electrode material;
Figure 459310DEST_PATH_IMAGE007
SOC =0%, the amount of lithium insertion corresponding to the negative electrode material,
Figure 726344DEST_PATH_IMAGE007
=
Figure 721982DEST_PATH_IMAGE006
full battery capacity/theoretical capacity of the negative electrode material.
For the state of the negative electrode material of a lithium battery, the negative electrode material molecule Li y C 6 The change of the quantity of the middle Li electrons is positively correlated with the SOC, namely the larger the SOC is, the larger the lithium embedding quantity is, and the SOC can be converted into the lithium embedding quantity of the cathode material through the above formula. Further, when the SOC is changed from 0% to 100%, y is changed in a narrower interval. Through the mode, the lithium insertion amount-OCV curve of the negative electrode material can be obtained through the technical scheme of the application in a mode of directly measuring and obtaining the discharge current-voltage curve under large current. And the DOD-V curve data under different discharge multiplying powers can also be directly used, and the lithium insertion amount-OCV curve of the negative electrode material can be obtained by the technical scheme of the application.
In a third aspect, an apparatus for obtaining a secondary battery SOC-OCV curve and a secondary battery electrode material lithium insertion amount-OCV curve is provided.
In order to make the aforementioned and other objects, features and advantages of the invention comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a DOD-V curve of full cell depth of discharge for the present invention;
FIG. 2 is a full cell discharge current-voltage curve of the present invention;
FIG. 3 is a full cell SOC-OCV curve of the present invention;
FIG. 4 is a DOD-V curve of the depth of discharge of the positive electrode material of the present invention;
FIG. 5 is a discharge current-voltage curve of the positive electrode material of the present invention;
FIG. 6 is a SOC-OCV curve of the positive electrode material of the present invention;
FIG. 7 is a plot of the amount of embedded lithium in the positive electrode material of the present invention versus OCV;
FIG. 8 is a DOD-V curve of the depth of discharge of the anode material of the present invention;
fig. 9 is a discharge current-voltage curve of the negative electrode material of the present invention;
fig. 10 is a SOC-OCV curve of the negative electrode material of the present invention;
fig. 11 is a plot of lithium insertion versus OCV for the negative electrode material of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. 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 invention.
The first embodiment is as follows:
a method for acquiring a full-cell SOC-OCV curve of a secondary battery includes the following steps:
as shown in fig. 1, discharge curves (DOD-V curves) of the secondary battery at discharge rates of 0.3C, 1C, 2C, and 3C were obtained, respectively;
based on the obtained discharge curve (DOD-V curve), a plurality of sets of discharge current and voltage data at a given depth of discharge are obtained.
Drawing a discharge current-voltage curve as shown in fig. 2 based on the obtained plurality of sets of discharge current and voltage data;
and extending the drawn discharge current-voltage curve to a position where the discharge current is 0C according to a linear fitting mode to obtain a target curve. Wherein the target curve is a discharge current-voltage curve with the current increasing from 0C.
Based on the target curve, the target voltage data of the corresponding position of the target curve can be determined when the discharge current is 0C;
the target voltage data is the OCV of the full cell;
finally, based on the given depth of discharge and the target voltage data, the SOC-OCV curve as shown in fig. 3 is obtained.
The DOD-V data can be obtained through discharge curves under different discharge rates, and the data is conventionally provided by battery manufacturers and is very accurate to obtain. Of course, the above data can also be obtained by measuring with a test device at a plurality of different depths of discharge.
In addition, the target curve obtained by the method just needs to find a voltage point with the discharge current of 0.020C or less based on the target curve, so that the usable target voltage (equivalent to the OCV) is obtained equivalently, and the OCV can be obtained quickly without direct measurement. Of course, considering the influence of polarization, the optimum voltage point is when the discharge current is equal to 0C, and the resulting voltage is the most accurate OCV.
Example two:
the method for obtaining the lithium intercalation amount-OCV curve of the cathode material by adopting a third electrode test under an NCM 333/graphite system comprises the following steps:
implanting a third electrode in the lithium battery;
and connecting the third electrode with a positive electrode, wherein the positive electrode is made of NCM 333.
As shown in fig. 4, discharge curves (DOD-positive electrode potential curves) at discharge rates of the positive electrode material at 0.3C, 0.5C, 1C, and 2C were measured;
acquiring a plurality of groups of discharge current and voltage data under a given discharge depth based on the measured positive electrode discharge curve (DOD-V curve);
drawing a discharge current-voltage curve as shown in fig. 5 based on the obtained sets of discharge current and voltage data;
and extending the drawn discharge current-voltage curve to a position where the current is equal to 0C according to a linear fitting mode to obtain a target curve. Wherein the target curve is a discharge current-voltage curve with the current increasing from 0C.
And obtaining target voltage data of the corresponding position of the target curve when the current is 0C based on the target curve.
The target voltage data is OCV of the positive electrode material.
Based on the given depth of discharge and the target voltage data, the positive electrode material SOC-OCV curve was obtained as shown in fig. 6. Wherein the conversion of the amount of lithium intercalation and SOC is obtained by the following formula:
the chemical formula of the state of the anode material is Li x MO 2 (M = one or more of Ni, Co, Mn elements, the sum of the stoichiometric ratios being 1, 0<x<1）；
x satisfies the following formula:
Figure 390860DEST_PATH_IMAGE001
wherein:
Figure 118645DEST_PATH_IMAGE002
is a DOD value;
Figure 182895DEST_PATH_IMAGE003
the corresponding lithium insertion amount of the positive electrode material is SOC = 100%;
Figure 919907DEST_PATH_IMAGE004
SOC =0%, the amount of lithium insertion corresponding to the positive electrode material,
Figure 177713DEST_PATH_IMAGE004
=
Figure 607558DEST_PATH_IMAGE003
+ full cell capacity/theoretical capacity of the anode material;
based on the obtained SOC-OCV curve of the cathode material, a lithium intercalation amount-OCV curve of the cathode material as shown in fig. 7 was obtained.
Example three:
under an NCM 333/graphite system battery system, the negative electrode is made of graphite materials, and a third electrode battery test is carried out to obtain the method for obtaining the lithium intercalation amount-OCV curve, which comprises the following steps:
implanting a third electrode in the lithium battery;
connecting the third electrode with a negative electrode, wherein the negative electrode material is a graphite material;
measuring the discharge curve (DOD-negative electrode potential curve) of the negative electrode material at the discharge rate of 0.3C, 0.5C, 1C and 2C as shown in FIG. 8;
based on the measured negative electrode discharge curve (DOD-V curve), acquiring a plurality of groups of discharge current and voltage data under a given discharge depth;
based on the obtained sets of discharge current and voltage data, a discharge current-voltage curve is plotted as shown in fig. 9;
and extending the discharge current-voltage curve to the position with the current of 0C according to the drawn discharge current-voltage curve in a linear fitting mode to obtain a target curve. Wherein the target curve is a discharge current-voltage curve with a current increasing from 0C.
And obtaining target voltage data of the corresponding position of the target curve when the current is 0C based on the target curve.
The target voltage data is OCV of the negative electrode material;
based on the given depth of discharge and the target voltage data, as shown in fig. 10, the negative electrode material SOC-OCV curve was obtained. Wherein the conversion of the amount of lithium intercalation and SOC is obtained by the following formula:
the chemical formula of the cathode material is Li y C 6 (0<y<1)；
y satisfies the following formula:
Figure 645921DEST_PATH_IMAGE005
wherein:
Figure 655465DEST_PATH_IMAGE002
is the DOD value;
Figure 298936DEST_PATH_IMAGE006
when SOC =100%, the intercalation amount corresponding to the negative electrode material;
Figure 430840DEST_PATH_IMAGE007
the insertion amount corresponding to the negative electrode material is SOC =0%,
Figure 159762DEST_PATH_IMAGE007
=
Figure 972997DEST_PATH_IMAGE006
full battery capacity/theoretical capacity of the negative electrode material.
Based on the obtained negative electrode material SOC-OCV curve, a negative electrode material lithium intercalation amount-OCV curve as shown in fig. 11 was obtained.

Claims (6)

1. A method of obtaining a lithium intercalation amount-OCV curve of a secondary battery electrode material, comprising:
acquiring a plurality of groups of discharge current and voltage data of the anode material based on the given discharge depth;
drawing a discharge current-voltage curve based on the obtained multiple groups of discharge current and voltage data of the anode material;
determining target voltage data based on the drawn discharge current-voltage curve;
obtaining an SOC-OCV curve of the anode material based on the given discharge depth and the target voltage data;
based on the obtained SOC-OCV curve of the cathode material, obtaining a lithium insertion amount-OCV curve of the cathode material,
wherein a positive electrode material lithium insertion amount-OCV curve is obtained, comprising the following steps:
the chemical formula of the cathode material is Li x MO 2 Wherein M can be one or more of Ni, Co or Mn, and the sum of the stoichiometric ratio is 1, 0<x<1；
x satisfies the following formula:
Figure FDA0003779949650000011
wherein the content of the first and second substances,
DOD i is a DOD value;
Figure FDA0003779949650000012
when SOC is 100%, the corresponding lithium insertion amount of the positive electrode material;
Figure FDA0003779949650000013
when SOC is 0%, the corresponding lithium insertion amount of the anode material,
Figure FDA0003779949650000014
Figure FDA0003779949650000015
2. a method of obtaining a lithium intercalation amount-OCV curve of a secondary battery electrode material, comprising:
acquiring a plurality of groups of discharge current and voltage data of the cathode material based on the given discharge depth;
drawing a discharge current-voltage curve based on the obtained multiple groups of discharge current and voltage data of the cathode material;
determining target voltage data based on the drawn discharge current-voltage curve;
obtaining an SOC-OCV curve of the cathode material based on the given discharge depth and the target voltage data;
obtaining a negative electrode material lithium insertion amount-OCV curve based on the obtained negative electrode material SOC-OCV curve;
wherein obtaining the lithium insertion amount-OCV curve of the negative electrode material comprises the following steps:
the chemical formula of the cathode material is Li y C 6 Wherein 0 is<y<1；
y satisfies the following formula:
Figure FDA0003779949650000021
wherein the content of the first and second substances,
DOD i is a DOD value;
Figure FDA0003779949650000022
when the SOC is 100%, the intercalation amount corresponding to the negative electrode material;
Figure FDA0003779949650000023
when SOC is 0%, the lithium insertion amount corresponding to the negative electrode material,
Figure FDA0003779949650000024
Figure FDA0003779949650000025
3. the method for obtaining the lithium intercalation amount-OCV curve of the electrode material of the secondary battery according to claim 1 or 2, wherein a plurality of sets of discharge current and voltage data of the electrode material are obtained based on a given depth of discharge, comprising the steps of:
respectively measuring discharge curves of the electrode material under different discharge multiplying powers;
based on the measured discharge curve, multiple sets of discharge current and voltage data at a given depth of discharge are obtained.
4. The method for obtaining the lithium intercalation amount-OCV curve of the electrode material of the secondary battery according to claim 3, wherein the discharge curves of the electrode material at different discharge rates are respectively measured, comprising the steps of:
implanting a third electrode in the lithium battery;
connecting the third electrode with the positive electrode material or the negative electrode material:
and measuring the discharge curves of the anode material or the cathode material under different discharge multiplying powers.
5. The method for obtaining a lithium intercalation amount-OCV curve of a secondary battery electrode material according to claim 1 or 2, wherein the target voltage data is determined based on the plotted discharge current-voltage curve, comprising the steps of:
extending the drawn discharge current-voltage curve to a position where the current is less than or equal to 0.020C according to the curve extension trend to obtain a target curve;
obtaining target voltage data of corresponding positions of the target curve when the current is less than or equal to 0.020C based on the target curve;
the target voltage data is OCV of the electrode material.
6. An apparatus for obtaining a lithium intercalation amount-OCV curve of a secondary battery electrode material, characterized in that: the device comprises a memory and a processor, wherein the memory is stored with at least one program instruction, and the processor is used for realizing the method for the lithium intercalation amount-OCV curve of the secondary battery electrode material according to any one of claims 1-5 by loading and executing the at least one program instruction.
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