CN114578229B - Power battery state of health determination method, apparatus and readable storage medium - Google Patents
Power battery state of health determination method, apparatus and readable storage medium Download PDFInfo
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- 230000036541 health Effects 0.000 title claims abstract description 64
- 238000000034 method Methods 0.000 title claims abstract description 51
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- 238000004422 calculation algorithm Methods 0.000 claims abstract description 31
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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]
- G01R31/367—Software therefor, e.g. for battery testing using modelling or look-up tables
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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]
- G01R31/385—Arrangements for measuring battery or accumulator variables
- G01R31/387—Determining ampere-hour charge capacity or SoC
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- 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
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Abstract
The invention discloses a method, a device and a computer readable storage medium for determining the health state of a power battery, wherein the method comprises the following steps: acquiring a real-time first SOC of the power battery according to a battery equivalent model of the power battery, and determining a first SOC change rate according to the real-time first SOC; acquiring a real-time second SOC of the power battery according to an SOC estimation algorithm, and determining a second SOC change rate according to the real-time second SOC; determining a capacity attenuation amount of the power battery according to the first SOC change rate and the second SOC change rate; and determining the health state of the power battery according to the capacity attenuation.
Description
Technical Field
The present invention relates to the field of vehicle battery detection technologies, and in particular, to a method and apparatus for determining a state of health of a power battery, and a readable storage medium.
Background
The power battery generally has a plurality of single batteries (also referred to as single battery cells), and due to the differences of the production, use environment, self-discharge and the like of the power battery, the battery health degree can be changed between the single batteries of the power battery in the random dynamic working condition operation process, so that a battery management system on a vehicle is required to have a battery health state estimation function, thereby ensuring that the health condition of the battery can be accurately estimated to provide a basis for vehicle control.
In the prior art, the current method mainly obtains the health state of the power battery by calculating the attenuation of the capacity of the power battery and checking a table by utilizing the relation between the total charge and discharge electric quantity and the attenuation, but the prior art usually has larger current integration error and battery SOC estimation error, and the table checking method is an open loop method, and has errors in the table checking method for the power battery with larger inconsistency, so the health state estimation method of the power battery in the prior art has lower accuracy.
Disclosure of Invention
The invention provides a method and a device for determining the health state of a power battery and a computer readable storage medium, which are used for solving the problem of low accuracy of a power battery health state estimation method in the prior art.
A power battery state of health determination method, comprising:
acquiring a real-time first SOC of the power battery according to a battery equivalent model of the power battery, and determining a first SOC change rate according to the real-time first SOC;
acquiring a real-time second SOC of the power battery according to an SOC estimation algorithm, and determining a second SOC change rate according to the real-time second SOC;
Determining a capacity attenuation amount of the power battery according to the first SOC change rate and the second SOC change rate;
and determining the health state of the power battery according to the capacity attenuation.
Further, the acquiring the real-time first SOC of the power battery according to the battery equivalent model of the power battery includes:
A second-order RC equivalent circuit model corresponding to the power battery is pre-built and used as the battery equivalent model;
Calculating the real-time open-circuit voltage of the power battery through the second-order RC equivalent circuit model, the real-time battery current and the output voltage of the power battery;
and acquiring the first SOC of the power battery in real time according to the relation between the open-circuit voltage and the residual electric quantity of the power battery.
Further, the acquiring the real-time second SOC of the power battery according to the SOC estimation algorithm includes:
And acquiring the second SOC of the power battery in real time through a preset ampere-hour integration algorithm.
Further, the obtaining the second SOC of the power battery in real time through a preset ampere-hour integration algorithm includes:
determining the second SOC of the power battery in real time by:
SOC2＝SOC0-IA/C；
wherein SOC 2 represents the second SOC, SOC 0 represents an initial SOC value of the power battery, η 1 represents coulombic efficiency of the power battery, η 2 represents charge-discharge efficiency of the power battery, C represents a total capacity of the power battery, and I is a battery current of the power battery.
Further, the determining the capacity fade amount of the power battery according to the first SOC change rate and the second SOC change rate includes:
And determining the capacity attenuation of the power battery through a least square identification method, the first SOC change rate and the second SOC change rate.
Further, the determining the capacity attenuation amount of the power battery by the least squares recognition method, the first SOC change rate, and the second SOC change rate includes:
Determining whether the first and second SOC change rates are different;
If the first and second SOC change rates are different, the following SOC estimation equation is constructed: SOC 1(1+dC)+off＝SOC2;SOC1 represents the first SOC, dC represents the capacity reduction amount of the power battery, off represents the capacity compensation value of the power battery, SOC 2 represents the second SOC, and C represents the total capacity of the power battery;
constructing the following attenuation result matrix according to the SOC estimation equation
bk＝[ΔSOC(1) ΔSOC(2) ... ΔSOC(k)]T；
ΔSOC＝SOC2-SOC1；
Wherein k represents a kth single battery in the power battery;
According to the attenuation result matrix And acquiring the capacity attenuation of the power battery.
A power battery state of health determination apparatus, comprising:
The first acquisition module is used for acquiring a real-time first SOC of the power battery according to a battery equivalent model of the power battery;
the first determining module is used for determining a first SOC change rate according to the first SOC in real time;
the second acquisition module is used for acquiring a real-time second SOC of the power battery according to an SOC estimation algorithm;
The second determining module is used for determining a second SOC change rate according to the real-time second SOC;
A third determining module, configured to determine a capacity attenuation amount of the power battery according to the first SOC variation rate and the second SOC variation rate;
and the fourth determining module is used for determining the health state of the power battery according to the capacity attenuation.
The power battery health state determining device comprises a memory, a processor and a computer program stored in the memory and capable of running on the processor, wherein the processor realizes the steps of the power battery health state determining method when executing the computer program.
A computer readable storage medium storing a computer program which when executed by a processor implements the steps of the power battery state of health determination method described above.
In one scheme provided by the method, the device and the storage medium for determining the state of health of the power battery, firstly, acquiring a real-time first SOC of the power battery according to a battery equivalent model of the power battery, and determining a first SOC change rate according to the real-time first SOC; acquiring a real-time second SOC of the power battery according to an SOC estimation algorithm, and determining a second SOC change rate according to the real-time second SOC; determining the capacity attenuation of the power battery according to the first SOC change rate and the second SOC change rate; and determining the health state of the power battery according to the capacity attenuation. Therefore, the scheme is characterized in that two kinds of SOCs of the power battery are determined through two different modes, including SOCs obtained by using an accurate battery equivalent model, then different SOCs change rates obtained in the two modes can be obtained, the SOCs obtained by using the accurate battery model are used as references, the attenuation condition of the capacity of the power battery can be judged, the health state of the battery is finally obtained, the stability and reliability are higher, the practicability is higher, and the accuracy of the health state estimation is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the embodiments of the present invention will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a method for determining a state of health of a power battery according to an embodiment of the invention;
FIG. 2 is a schematic diagram of a second order RC equivalent circuit model according to an embodiment of the present invention;
FIG. 3 is a schematic diagram showing a variation of the first SOC and the second SOC according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a power battery state of health determination device according to an embodiment of the present invention;
fig. 5 is a schematic diagram of another configuration of a power battery state of health determination device according to an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The present invention provides a power battery state of health determination method, which is applicable to various vehicles for estimating the state of health of a power battery in the vehicle, and is described in detail below.
In one embodiment, as shown in fig. 1, a method for determining a health status of a power battery is provided, including the following steps:
S10: and acquiring a real-time first SOC of the power battery according to a battery equivalent model of the power battery, and determining a first SOC change rate according to the real-time first SOC.
In the invention, a battery equivalent model corresponding to the power battery is firstly constructed, and then the battery equivalent model and the real-time parameters of the power battery can be utilized to obtain the real-time first SOC (State ofcharge ) of the power battery. That is, the first SOC referred to in the present invention refers to the SOC of the power battery in real time acquired using the battery equivalent model.
It should be noted that, after the real-time first SOC of the power battery is obtained, the first SOC value of each moment of time after the power battery runs for a period of time may be known, so that the SOC change rate corresponding to the first SOC value may be determined.
In addition, it should be noted that various manners of constructing the equivalent model of the battery may be adopted, and the present invention is not limited thereto.
S20: and acquiring a real-time second SOC of the power battery according to an SOC estimation algorithm, and determining a second SOC change rate according to the real-time second SOC.
In the invention, besides the first SOC change rate corresponding to the power battery is obtained by using the battery equivalent model, the real-time second SOC of the power battery is obtained according to the SOC estimation algorithm, that is, the second SOC refers to the real-time SOC of the power battery obtained by using the SOC estimation algorithm.
After the real-time second SOC of the power battery is obtained, the second SOC value of each moment of time after the power battery runs for a period of time can be known, so that the SOC change rate corresponding to the two SOC values can be determined.
It should be noted that, the SOC estimation algorithm of the present invention refers to a method for estimating the SOC value of the current power battery by using the relevant state parameter of the current power battery, and the embodiment of the present invention is not limited.
S30: and determining the capacity attenuation of the power battery according to the first SOC change rate and the second SOC change rate.
S40: and determining the health state of the power battery according to the capacity attenuation.
As can be seen from the above steps S10-S20, the first and second SOCs are SOCs obtained by two different modes, and the first and second SOCs change rates are SOCs corresponding to the two different modes, and since the first SOCs change rates are obtained by using an accurate battery equivalent model and the first SOCs change rates are obtained by using an SOC estimation algorithm, whether the capacity of the power battery is attenuated and the corresponding capacity attenuation amount can be continuously determined by using the difference between the first and second SOCs, and since the capacity attenuation amount of the power battery reflects the health condition of the power battery, the health state of the power battery can be determined according to the capacity attenuation amount of the power battery.
In one embodiment, the power battery may be considered to be in an unhealthy state if the capacity decay of the power battery is greater than a certain capacity threshold, and may be considered to be in a healthy state if the capacity decay of the power battery is less than or equal to the capacity threshold.
It can be seen that the embodiment of the invention provides a method for determining the state of health of a power battery, which is characterized in that two kinds of SOCs of the power battery are determined by two different modes, including SOCs obtained by using an accurate battery model, then different SOCs change rates obtained in the two modes can be obtained, the SOCs obtained by using the accurate battery model are used as references, the attenuation condition of the capacity of the power battery can be judged, and finally the state of health of the battery is obtained, so that the method is more stable and reliable, has stronger practicability, and improves the accuracy of estimating the state of health.
In an embodiment, in step S10, the method for acquiring the real-time first SOC of the power battery according to the battery equivalent model of the power battery specifically includes the following steps:
S101: and constructing a second-order RC equivalent circuit model corresponding to the power battery in advance to serve as the battery equivalent model.
Referring to fig. 2, the present invention can determine relevant parameters of a second-order RC equivalent circuit model according to table look-up of a discharging state, an SOC value, a temperature value, etc. of a power battery, thereby obtaining basic parameters of the second-order RC equivalent circuit model, including parameters such as an equivalent resistor and an equivalent capacitor, etc., and finally construct a second-order RC equivalent circuit model corresponding to the power battery as a battery equivalent model of the power battery.
It will be appreciated that for a power cell, the resistance of the power cell typically includes both the polarization resistance and the ohmic resistance, which typically includes the electrode material of the power cell, the electrolyte, and the contact resistance of the various components; the polarization resistance value is the resistance generated by polarization during the chemical reaction of the power battery, so that a second-order RC equivalent circuit model corresponding to the power battery can be constructed as an equivalent battery model of the power battery according to the characteristics of the power battery.
In the second-order RC equivalent circuit model corresponding to fig. 2, U OC represents the open circuit voltage of the power battery, U t represents the output voltage of the power battery, R 0、R1 and R 2 respectively represent the equivalent resistances in the circuit model, and C 1 and C 2 respectively represent the equivalent capacitances, and each equivalent parameter of the equivalent circuit model can be determined by the relevant parameter of the power battery, which is not described in detail herein. The relationships of the second-order RC equivalent circuit model can be as follows:
Ut＝UOC-U1-U2-IR0；
S102: and calculating the real-time open-circuit voltage of the power battery through the second-order RC equivalent circuit model, the real-time battery current and the output voltage of the power battery.
In the present invention, the real-time battery current I and the output voltage U t of the power battery can be obtained in real time and input into the relational expression of the constructed second-order RC equivalent circuit model, so that the real-time Open Circuit Voltage (OCV) of the power battery can be correspondingly obtained, that is, the open circuit voltage at this time is obtained based on the second-order RC equivalent circuit model.
S103: and acquiring the first SOC of the power battery in real time according to the mapping relation between the open-circuit voltage and the SOC of the power battery.
It can be understood that the open-circuit voltage of the power battery has a corresponding relation with the SOC value of the power battery, after the real-time open-circuit voltage of the power battery is obtained according to the second-order RC equivalent circuit model, the corresponding SOC value can be determined according to the real-time open-circuit voltage of the power battery, and the SOC value obtained correspondingly by using the second-order RC equivalent circuit model is referred to as the first SOC.
It should be noted that, in an application scenario, a mapping relationship between an open-circuit voltage of a power battery and an SOC of the power battery may be stored in an OCV-SOC mapping table, and when the open-circuit voltage of the power battery is obtained, a first SOC corresponding to the open-circuit voltage may be obtained by looking up the OCV-SOC mapping table.
It can be seen that the embodiment of the invention provides a specific second-order RC equivalent circuit model, and the feasibility of the scheme is improved according to the corresponding first SOC obtained according to the second-order RC equivalent circuit model. And because the second-order RC equivalent circuit model is an accurate equivalent model, an accurate reference basis can be provided for the follow-up assessment of whether the capacity of the power battery is attenuated and the attenuation amount, and the practicability of the scheme is improved.
In an embodiment, in step S20, the step of obtaining the real-time second SOC of the power battery according to an SOC estimation algorithm refers to obtaining the real-time second SOC of the power battery through a preset ampere-hour integration algorithm (AH integration algorithm).
It should be noted that, in the embodiment of the present invention, a plurality of different ampere-hour integration algorithms may be adopted as the preset ampere-hour integration algorithm, so as to obtain the real-time second SOC of the power battery.
In an embodiment, the acquiring the second SOC of the power battery in real time through a preset ampere-hour integration algorithm refers to:
determining the second SOC of the power battery in real time by:
SOC2＝SOC0-IA/C；
SOC 2 represents the second SOC, SOC 0 represents an initial SOC value of the power battery, η 1 represents coulomb efficiency of the power battery, η 2 represents charge/discharge efficiency of the power battery, C represents total capacity of the power battery, I represents battery current of the power battery, I A represents ampere-hour integrated current, and the initial SOC value, coulomb efficiency, charge/discharge efficiency and the like may be obtained by reading or converting power battery parameters, which are not described in detail herein.
In an embodiment, in step S30, that is, determining the capacity attenuation of the power battery according to the first SOC variation rate and the second SOC variation rate, the capacity attenuation of the power battery is determined by a least squares recognition method, the first SOC variation rate and the second SOC variation rate. It can be understood that the least square method is a mathematical tool widely applied in many fields of data processing such as error estimation, uncertainty, system identification, prediction, and forecasting, and in the present invention, a process of identifying the capacity attenuation of the power battery by using the least square method is called as a least square identification method.
In one embodiment, the capacity attenuation amount of the power battery is determined by a least square identification method, the first SOC change rate and the second SOC change rate, and specifically includes the following steps:
s301: determining whether the first and second rates of change of SOC are different.
In the present invention, after the first SOC change rate and the second SOC change rate are determined, it may be determined whether the first SOC change rate and the second SOC change rate are the same.
As shown in fig. 3, it can be understood that the capacity attenuation amount of the power battery is obtained, that is, the capacity of the power battery needs to be considered, and the line 2 shows a change schematic line of the first SOC, in which the change is performed with time t in a period of one charge and discharge; line 1 is a schematic line of the second SOC change obtained by ampere-hour integration calculation, and as is apparent from fig. 3, the different slopes of line 1 and line 2, that is, the different first SOC change rate and the first SOC change rate, may result in the first SOC change rate and the first SOC change rate, mainly due to the inaccurate total capacity of the power battery when the estimation algorithm (such as the ampere-hour integration algorithm) is adopted.
As can be seen, if it is determined that the first SOC variation rate and the second SOC variation rate are different or the difference exceeds the preset rate, it may be determined that the power battery has attenuation; if the first SOC change rate and the second SOC change rate are the same or the difference value does not exceed the preset rate, the power battery can default to have no attenuation.
If the first SOC change rate and the second SOC change rate are determined to be the same, it is indicated that there is no attenuation in the capacity of the power battery at this time, and if the first SOC change rate and the second SOC change rate are determined to be different, the capacity attenuation amount of the power battery may be continuously determined according to the relationship between the first SOC and the second SOC, as shown in steps S302-S304.
S302: if the first and second SOC change rates are different, the following SOC estimation equation is constructed.
If the first SOC change rate and the second SOC change rate are different, that is, if the difference between the first SOC change rate and the second SOC change rate is smaller than the preset rate or greater than the preset rate, the following SOC estimation equation may be constructed: SOC 1(1+dC)+off＝SOC2.
SOC 1 represents the first SOC, dC represents the capacity reduction amount of the power battery, off represents the capacity compensation value of the power battery, SOC 2 represents the second SOC, and C represents the total capacity of the power battery.
S303: constructing the following attenuation result matrix according to the SOC estimation equation
S304: according to the attenuation result matrixAnd acquiring the capacity attenuation of the power battery.
It should be noted that after constructing the SOC estimation equation, a corresponding recurrence formula may be constructed according to the least square method, in the present invention, the following attenuation result matrix is constructed according to the SOC 1(1+dC)+off＝SOC2
bk＝[ΔSOC(1) ΔSOC(2) ... ΔSOC(k)]T；
ΔSOC＝SOC2-SOC1；
Wherein k represents a kth single battery in the power battery;
Specifically, taking the second SOC as an example obtained through the ampere-hour calculation algorithm, the corresponding constructed SOC estimation equation is: SOC 1(1+dC)+off＝SOC0-IA/C, then we can simply write:
ΔSOC＝(SOC0-IA/C)-SOC1；
Continuing to convert to be available
Let b k＝[ΔSOC(1) ΔSOC(2) ... ΔSOC(k)]T be the case,Then the/>, after conversion, can be obtained
It can be seen that the attenuation result matrix can be obtained through the arrangementAnd the attenuation result matrix/>The capacity fade dC of the power cell is included. Therefore, according to the embodiment of the invention, the capacity attenuation condition and the corresponding capacity attenuation amount of the power battery can be known, so that the state of health of the power battery is judged according to the capacity attenuation of the power battery, the state of health evaluation result of the power battery is effectively improved, the evaluation error caused by current integration error and the like which are evaluated by adopting an ampere-hour algorithm in the prior art is avoided, and the accuracy of evaluating the state of health of the power battery is effectively improved.
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, and should not limit the implementation process of the embodiment of the present invention.
In an embodiment, a power battery state of health determining device is provided, which corresponds to the power battery state of health determining method in the above embodiment one by one. As shown in fig. 4, the power battery state of health determination apparatus includes a first acquisition module 101, a second acquisition module 102, a third acquisition module 103, and a fourth acquisition module 104. The functional modules are described in detail as follows:
a first obtaining module 101, configured to obtain a real-time first SOC of the power battery according to a battery equivalent model of the power battery;
a first determining module 102, configured to determine a first SOC variation rate according to the first SOC in real time;
A second obtaining module 103, configured to obtain a real-time second SOC of the power battery according to an SOC estimation algorithm;
A second determining module 104, configured to determine a second SOC change rate according to the real-time second SOC;
a third determining module 105 for determining a capacity attenuation amount of the power battery according to the first SOC variation rate and the second SOC variation rate;
and the fourth determining module is used for determining the health state of the power battery according to the capacity attenuation.
In an embodiment, the first obtaining module 101 is specifically configured to:
A second-order RC equivalent circuit model corresponding to the power battery is pre-built and used as the battery equivalent model;
Calculating the real-time open-circuit voltage of the power battery through the second-order RC equivalent circuit model, the real-time battery current and the output voltage of the power battery;
And acquiring the first SOC of the power battery in real time according to the mapping relation between the open-circuit voltage and the SOC of the power battery.
In an embodiment, the second obtaining module is specifically configured to:
And acquiring the second SOC of the power battery in real time through a preset ampere-hour integration algorithm.
The second acquisition module is specifically configured to:
determining the second SOC of the power battery in real time by:
SOC2＝SOC0-IA/C；
wherein SOC 2 represents the second SOC, SOC 0 represents an initial SOC value of the power battery, η 1 represents coulombic efficiency of the power battery, η 2 represents charge-discharge efficiency of the power battery, C represents a total capacity of the power battery, and I is a battery current of the power battery.
In an embodiment, the third determining module 105 is specifically configured to: and determining the capacity attenuation of the power battery through a least square identification method, the first SOC change rate and the second SOC change rate.
In an embodiment, the third determining module 105 is specifically configured to:
Determining whether the first and second SOC change rates are different;
If the first and second SOC change rates are different, the following SOC estimation equation is constructed: SOC 1(1+dC)+off＝SOC2;SOC1 represents the first SOC, dC represents the capacity reduction amount of the power battery, off represents the capacity compensation value of the power battery, SOC 2 represents the second SOC, and C represents the total capacity of the power battery;
constructing the following attenuation result matrix according to the SOC estimation equation
bk＝[ΔSOC(1) ΔSOC(2) ... ΔSOC(k)]T；
ΔSOC＝SOC2-SOC1；
Wherein k represents a kth single battery in the power battery;
According to the attenuation result matrix And acquiring the capacity attenuation of the power battery.
It can be seen that the embodiment of the invention provides a power battery health status determining device, which is characterized in that two kinds of SOCs of a power battery are determined by two different modes, including SOCs obtained by using an accurate battery model, then different SOCs change rates obtained in the two modes can be obtained, the SOCs obtained by using the accurate battery model are used as references, the attenuation condition of the capacity of the power battery can be determined, and finally the health status of the battery is obtained, so that the power battery health status determining device is more stable and reliable, has stronger practicability, and improves the accuracy of health status estimation.
For specific limitations on the power battery state of health determination device, reference may be made to the above limitations on the power battery state of health determination method, and no further description is given here. The respective modules in the above-described power battery state of health determination device may be implemented in whole or in part by software, hardware, and combinations thereof. The above modules may be embedded in hardware or may be independent of a processor in the controller, or may be stored in software in a memory in the controller, so that the processor may call and execute operations corresponding to the above modules.
In one embodiment, a power battery state of health determination device is provided, which may be a controller on a vehicle, the internal structure of which may be as shown in fig. 5. The power battery state of health determination device includes a processor, a memory, a network interface, and a database connected by a system bus. Wherein the processor of the power battery state of health determination device is configured to provide computing and control capabilities. The memory of the power battery state of health determination device includes a storage medium and an internal memory. The storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and computer programs in the storage media. The computer program is executed by a processor to implement a method of determining a state of health of a power battery.
In one embodiment, a power battery state of health determination apparatus is provided, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, the processor implementing the following steps when executing the computer program:
acquiring a real-time first SOC of the power battery according to a battery equivalent model of the power battery, and determining a first SOC change rate according to the real-time first SOC;
acquiring a real-time second SOC of the power battery according to an SOC estimation algorithm, and determining a second SOC change rate according to the real-time second SOC;
Determining a capacity attenuation amount of the power battery according to the first SOC change rate and the second SOC change rate;
and determining the health state of the power battery according to the capacity attenuation.
In one embodiment, a computer readable storage medium is provided having a computer program stored thereon, which when executed by a processor, performs the steps of:
acquiring a real-time first SOC of the power battery according to a battery equivalent model of the power battery, and determining a first SOC change rate according to the real-time first SOC;
acquiring a real-time second SOC of the power battery according to an SOC estimation algorithm, and determining a second SOC change rate according to the real-time second SOC;
Determining a capacity attenuation amount of the power battery according to the first SOC change rate and the second SOC change rate;
and determining the health state of the power battery according to the capacity attenuation.
Those skilled in the art will appreciate that implementing all or part of the above described methods may be accomplished by way of a computer program stored on a non-transitory computer readable storage medium, which when executed, may comprise the steps of the embodiments of the methods described above. Any reference to memory, storage, database, or other medium used in embodiments provided herein may include non-volatile and/or volatile memory. The nonvolatile memory can include Read Only Memory (ROM), programmable ROM (PROM), electrically Programmable ROM (EPROM), electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms such as Static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double Data Rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (SYNCHLINK) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), among others.
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 above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will 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 invention, and are intended to be included in the scope of the present invention.
Claims (8)
1. A method for determining a state of health of a power battery, comprising:
acquiring a real-time first SOC of the power battery according to a battery equivalent model of the power battery, and determining a first SOC change rate according to the real-time first SOC;
acquiring a real-time second SOC of the power battery according to an SOC estimation algorithm, and determining a second SOC change rate according to the real-time second SOC;
Determining a capacity attenuation amount of the power battery according to the first SOC change rate and the second SOC change rate;
Determining the health state of the power battery according to the capacity attenuation;
The determining the capacity attenuation amount of the power battery according to the first SOC change rate and the second SOC change rate includes:
Determining the capacity attenuation of the power battery through a least square identification method, the first SOC change rate and the second SOC change rate;
the determining the capacity attenuation of the power battery by the least square identification method, the first SOC change rate and the second SOC change rate includes:
Determining whether the first and second SOC change rates are different;
If the first and second SOC change rates are different, the following SOC estimation equation is constructed: SOC 1 (1+dC)+off＝SOC2;SOC1 represents the first SOC, dC represents the capacity reduction amount of the power battery, off represents the capacity compensation value of the power battery, SOC 2 represents the second SOC, and C represents the total capacity of the power battery;
constructing the following attenuation result matrix according to the SOC estimation equation ：
；
bk＝[ΔSOC(1) ΔSOC(2) ...ΔSOC(k)]T；
；
ΔSOC＝SOC2-SOC1；
Wherein k represents a kth single battery in the power battery;
According to the attenuation result matrix And acquiring the capacity attenuation of the power battery.
2. The method for determining a state of health of a power battery according to claim 1, wherein the acquiring the real-time first SOC of the power battery according to the battery equivalent model of the power battery comprises:
A second-order RC equivalent circuit model corresponding to the power battery is pre-built and used as the battery equivalent model;
Calculating the real-time open-circuit voltage of the power battery through the second-order RC equivalent circuit model, the real-time battery current and the output voltage of the power battery;
And acquiring the first SOC of the power battery in real time according to the mapping relation between the open-circuit voltage and the SOC of the power battery.
3. The power battery state of health determination method of claim 1, wherein said obtaining said power battery real-time second SOC according to an SOC estimation algorithm comprises:
And acquiring the second SOC of the power battery in real time through a preset ampere-hour integration algorithm.
4. The method for determining a state of health of a power battery according to claim 3, wherein said obtaining said second SOC of said power battery in real time by a preset ampere-hour integration algorithm comprises:
determining the second SOC of the power battery in real time by:
SOC2＝SOC0-IA/C；
；
Wherein SOC 2 represents the second SOC, SOC 0 represents an initial SOC value of the power battery, η 1 represents coulomb efficiency of the power battery, η 2 represents charge/discharge efficiency of the power battery, C represents a total capacity of the power battery, and I represents a battery current of the power battery.
5. A power battery state of health determination apparatus, characterized by being applied to the power battery state of health determination method of claim 1, comprising:
The first acquisition module is used for acquiring a real-time first SOC of the power battery according to a battery equivalent model of the power battery;
the first determining module is used for determining a first SOC change rate according to the first SOC in real time;
the second acquisition module is used for acquiring a real-time second SOC of the power battery according to an SOC estimation algorithm;
The second determining module is used for determining a second SOC change rate according to the real-time second SOC;
A third determining module, configured to determine a capacity attenuation amount of the power battery according to the first SOC variation rate and the second SOC variation rate;
and the fourth determining module is used for determining the health state of the power battery according to the capacity attenuation.
6. The power cell state of health determination apparatus of claim 5, wherein said first determination module is specifically configured to:
And determining the capacity attenuation of the power battery through a least square identification method, the first SOC change rate and the second SOC change rate.
7. A power battery state of health determination device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that the processor implements the steps of the power battery state of health determination method according to any one of claims 1 to 4 when executing the computer program.
8. A readable storage medium storing a computer program, characterized in that the computer program when executed by a processor implements the steps of the power battery state of health determination method of any one of claims 1 to 4.
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