CN114578229A - Power battery state of health determination method, device and readable storage medium - Google Patents
Power battery state of health determination method, device and readable storage medium Download PDFInfo
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Abstract
The invention discloses a method and a device for determining the health state of a power battery and a computer readable storage medium, wherein the method part comprises the following steps: acquiring a real-time first SOC of the power battery according to the 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 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 amount.
Description
Technical Field
The invention relates to the technical field of vehicle battery detection, in particular to a method and a device for determining the health state of a power battery and a readable storage medium.
Background
The power battery is usually provided with a plurality of single batteries (also called single battery cores), and due to the reasons of the differences of the production, the use environment, the self-discharge and the like of the power battery, the battery health degree generated among the single batteries of the power battery can change in the random dynamic working condition operation process, so that a battery management system on a vehicle needs 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 obtains the health state of the power battery mainly by calculating the attenuation of the capacity of the power battery and looking up a table by utilizing the relation between the total charge and discharge capacity and the attenuation, but the method in the prior art usually has larger current integration error and battery SOC estimation error, and the table look-up method is an open-loop method, and for the power battery with larger inconsistency, the table look-up method also has error, so the method for estimating the health state 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 state of health of a power battery and a computer readable storage medium, which are used for solving the problem of low accuracy of a state of health estimation method of the power battery in the prior art.
A power battery state of health determination method includes:
acquiring a real-time first SOC of the power battery according to the 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 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 amount.
Further, the obtaining a 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 constructed in advance to serve 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 real-time first SOC of the power battery according to the relation between the open-circuit voltage and the residual capacity of the power battery.
Further, the obtaining of the real-time second SOC of the power battery according to the SOC estimation algorithm includes:
and acquiring the real-time second SOC of the power battery through a preset ampere-hour integration algorithm.
Further, the obtaining of the second SOC of the power battery in real time through a preset ampere-hour integration algorithm includes:
determining the real-time second SOC of the power battery by the following equation:
SOC2＝SOC0-IA/C；
therein, SOC2Representing said second SOC, SOC0Representing an initial SOC value, η, of the power cell1Representing the coulomb efficiency, eta, of the power cell2The charging and discharging efficiency of the power battery is represented, C represents the total capacity of the power battery, and I represents the battery current of the power battery.
Further, the determining the capacity decrement of the power battery according to the first SOC change rate and the second SOC change rate includes:
and determining the capacity attenuation amount of the power battery through a least square identification method and the first SOC change rate and the second SOC change rate.
Further, the determining the capacity decrement of the power battery by the least square recognition method, the first SOC change rate and the second SOC change rate includes:
determining whether the first and second rates of change of SOC are different;
if the first SOC change rate and the second SOC change rate are different, constructing an SOC estimation equation as follows: SOC1(1+dC)+off＝SOC2；SOC1Representing the first SOC, dC representing the capacity attenuation amount of the power battery, off representing the capacity compensation value of the power battery, and SOC2Representing the second SOC, and C representing the total capacity of the power battery;
constructing an attenuation quantity result matrix according to the SOC estimation equation
bk＝[ΔSOC(1) ΔSOC(2) ... ΔSOC(k)]T；
ΔSOC＝SOC2-SOC1；
Wherein k represents the kth single battery in the power battery;
according to the attenuation quantity result matrix
And acquiring the capacity attenuation amount 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 the battery equivalent model of the power battery;
the first determining module is used for determining a first SOC change rate according to the real-time first SOC;
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;
the third determination module is used for determining the capacity attenuation amount of the power battery according to the first SOC change rate and the second SOC change rate;
and the fourth determination module is used for determining the health state of the power battery according to the capacity attenuation amount.
A power battery state of health determination 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 state of health determination method when executing the computer program.
A computer-readable storage medium, in which a computer program is stored, which computer program, when being executed by a processor, carries out the steps of the above-mentioned power battery state of health determination method.
In one scheme provided by the method, the device and the storage medium for determining the state of health of the power battery, a first real-time SOC of the power battery is obtained according to a battery equivalent model of the power battery, and a first SOC change rate is determined according to the first real-time 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 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 amount. Therefore, the scheme is that the two SOCs of the power battery are determined in two different modes, the SOC obtained by the accurate battery equivalent model is utilized, then the difference of the SOC change rates obtained in the two modes can be obtained, the SOC obtained by the accurate battery model is utilized as a reference, the attenuation condition of the capacity of the power battery can be judged, the health state of the battery is obtained at last, the stability and reliability are improved, the practicability is high, and the accuracy of health state estimation is improved.
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In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments of the present invention will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without inventive labor.
Fig. 1 is a schematic flow chart of a method for determining the state of health of a power battery according to an embodiment of the invention;
FIG. 2 is a model diagram of a second order RC equivalent circuit model according to an embodiment of the present invention;
FIG. 3 is a schematic diagram illustrating a variation of the first SOC and the second SOC according to an embodiment of the invention;
FIG. 4 is a schematic structural diagram of a power battery state of health determination apparatus according to an embodiment of the present invention;
fig. 5 is another schematic structural diagram of the power battery state of health determination apparatus according to an embodiment 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 some, not all, embodiments of the present invention. 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 invention provides a power battery state of health determination method, which can be applied to various vehicles and is used 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 the state of health of a power battery is provided, which includes the following steps:
s10: the real-time first SOC of the power battery is obtained according to the battery equivalent model of the power battery, and a first SOC change rate is determined according to the real-time first SOC.
In the invention, a battery equivalent model corresponding to the power battery is constructed, and then a first real-time SOC (State of charge) of the power battery can be obtained by using the battery equivalent model and real-time parameters of the power battery. That is, the first SOC in the present invention refers to the real-time SOC of the power battery obtained by 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 the power battery at each time after a period of time operation is obtained, so that the SOC change rate corresponding to the first SOC value can be determined.
It should be noted that, various ways of constructing the battery equivalent model may be adopted, and the 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, namely 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 acquired, the second SOC value of the power battery at each time after a period of operation is passed can be known, so that the SOC change rate corresponding to the second SOC value can be determined.
It should be noted that the SOC estimation algorithm in 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 specifically.
S30: and determining the capacity attenuation amount of the power battery according to the first SOC change rate and the second SOC change rate.
S40: and determining the state of health 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 SOC values obtained by two different methods, and the first and second SOC change rates are SOC change rates corresponding to the two different methods, wherein the first SOC change rate is obtained by an accurate battery equivalent model, and the first SOC change rate is obtained by an SOC estimation algorithm, and by using the difference between the first and second SOC change rates, whether the capacity of the power battery is degraded or not and a corresponding capacity degradation amount can be continuously determined, and since the capacity degradation amount of the power battery reflects the health condition of the power battery, the health condition of the power battery can be determined according to the capacity degradation amount of the power battery.
In one embodiment, the power battery may be considered to be in an unhealthy state if the capacity fade of the power battery is greater than a certain capacity threshold, and may be considered to be in a healthy state if the capacity fade of the power battery is less than or equal to the capacity threshold.
Therefore, the embodiment of the invention provides a method for determining the health state of a power battery, which is characterized in that two kinds of SOC of the power battery are determined through two different modes, including the SOC obtained by using an accurate battery model, so that the difference of the change rates of the SOC obtained in the two modes can be obtained, the SOC obtained by using the accurate battery model is used as a reference, the attenuation condition of the capacity of the power battery can be judged, the health state of the battery is obtained finally, the method is more stable and reliable, the practicability is higher, and the accuracy of health state estimation is improved.
In an embodiment, in step S10, the obtaining a 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 pre-constructing a second-order RC equivalent circuit model corresponding to the power battery as the battery equivalent model.
Referring to fig. 2, the present invention may determine relevant parameters of the second-order RC equivalent circuit model according to a table lookup of a discharge state, an SOC value, a temperature value, etc. of the power battery, so as to obtain basic parameters of the second-order RC equivalent circuit model, including parameters such as an equivalent resistance and an equivalent capacitance, and finally construct the second-order RC equivalent circuit model corresponding to the power battery as the battery equivalent model of the power battery.
It is understood that, for a power battery, the resistance of the power battery generally includes polarization resistance and ohmic resistance, and the ohmic resistance generally includes contact resistance of electrode materials, electrolyte and various parts of the power battery; and 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 the 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, UOCIndicating the open circuit voltage, U, of the power celltRepresenting the output voltage, R, of the power cell0、R1And R2Respectively representing the equivalent resistance, C, in the circuit model1And C2Respectively representing the equivalent capacitance, 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 relations 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.
It should be noted that, in the present invention, the real-time battery current I and output voltage U of the power battery can be obtained in real timetAnd then, the Open Circuit Voltage (OCV) is obtained in real time by inputting the open circuit voltage into the relation of the second-order RC equivalent circuit model, that is, the open circuit voltage is obtained based on the second-order RC equivalent circuit model.
S103: and acquiring the real-time first SOC of the power battery 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 and the SOC value of the power battery have a corresponding relationship, 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 a first SOC.
In an application scenario, a mapping relationship between the open-circuit voltage of the power battery and the SOC of the power battery may exist 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.
Therefore, the embodiment of the invention provides a specific second-order RC equivalent circuit model, and the corresponding first SOC is obtained according to the second-order RC equivalent circuit model, so that the feasibility of the scheme is improved. And because the second-order RC equivalent circuit model is an accurate equivalent model, an accurate reference basis can be provided for subsequent evaluation of whether the capacity of the power battery is attenuated and the attenuation, and the practicability of the scheme is improved.
In one embodiment, in step S20, the obtaining of the second real-time SOC of the power battery according to the SOC estimation algorithm refers to obtaining the second real-time 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 used as the preset ampere-hour integration algorithm, so as to obtain the real-time second SOC of the power battery, in addition, the present invention may also use another SOC estimation algorithm to obtain the real-time second SOC of the power battery, for example, the estimation of the SOC of the power battery by using the kalman filter method is not limited specifically as the second SOC.
In an embodiment, the obtaining of the second real-time SOC of the power battery through a preset ampere-hour integration algorithm refers to:
determining the second SOC of the power battery in real time through the following equation:
SOC2＝SOC0-IA/C；
SOC2representing said second SOC, SOC0Representing an initial SOC value, η, of the power cell1Representing the coulomb efficiency, eta, of the power cell2Representing the charge-discharge efficiency of the power battery, C representing the total capacity of the power battery, I representing the battery current of the power battery, I representing the total capacity of the power batteryAThe ampere-hour integral current is represented, and the initial SOC value, the coulombic efficiency, the charge-discharge efficiency and the like can be obtained by reading or converting parameters of the power battery, and are not described in detail herein.
In one embodiment, the step S30, namely, determining the capacity attenuation amount of the power battery according to the first SOC variation rate and the second SOC variation rate, is to determine the capacity attenuation amount of the power battery through a least square recognition method and 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 subject fields of data processing such as error estimation, uncertainty, system identification and prediction, etc., and in the present invention, the process of identifying the capacity attenuation of the power battery by using the least square method is called as the least square identification method.
In one embodiment, the determining the capacity attenuation amount of the power battery by a least square identification method, the first SOC change rate and the second SOC change rate 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 and second rates of change of SOC are determined, it can be determined whether the first and second rates of change of SOC are the same.
As shown in fig. 3, it can be understood that, in the present invention, it is intended to obtain the capacity decrement of the power battery, that is, the change before and after the capacity of the power battery is considered, and line 2 is a line indicating the change of the first SOC with time t during one charge and discharge period; line 1 is a schematic line of the second SOC variation obtained by ampere-hour integration calculation, and as is apparent from fig. 3, the slope of line 1 is different from that of line 2, that is, the first SOC variation rate is different from the first SOC variation rate, which results in the first SOC variation rate and the first SOC variation rate, mainly due to the inaccurate total capacity of the power battery when the estimation algorithm (such as ampere-hour integration algorithm) is adopted.
If the first SOC change rate and the second SOC change rate are different or the difference value exceeds a preset rate, determining that the power battery has attenuation; if it is determined that the first and second rates of change of SOC are the same or the difference does not exceed a predetermined rate, then the absence of power battery degradation may be defaulted.
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 rates of change of SOC are different, then the following SOC estimation equation is constructed.
If the first SOC change rate and the second SOC change rate are different, that is, the difference between the first SOC change rate and the second SOC change rate is smaller than a preset rate, or larger than the preset rate, the first SOC change rate and the second SOC change rate may be set upThe SOC estimation equation is as follows: SOC1(1+dC)+off＝SOC2。
SOC1Representing the first SOC, dC representing the capacity attenuation amount of the power battery, off representing the capacity compensation value of the power battery, and SOC2And C represents the total capacity of the power battery.
S303: constructing the following attenuation quantity result matrix according to the SOC estimation equation
S304: according to the attenuation quantity result matrix
And acquiring the capacity attenuation amount of the power battery.
It should be noted that after the SOC estimation equation is constructed, the corresponding recursion formula can be constructed according to the least square method1(1+dC)+off＝SOC2Constructing the following attenuation result matrix
bk＝[ΔSOC(1) ΔSOC(2) ... ΔSOC(k)]T；
ΔSOC＝SOC2-SOC1；
Wherein k represents the kth single battery in the power battery;
specifically, taking the second SOC as an example obtained by the ampere-hour calculation algorithm, the corresponding constructed SOC estimation equation is as follows: SOC1(1+dC)+off＝SOC0-IA/C，It can be abbreviated as:
ΔSOC＝(SOC0-IA/C)-SOC1；
continue to convert to obtain
Let b bek＝[ΔSOC(1) ΔSOC(2) ... ΔSOC(k)]T，
Then conversion can obtain
As can be seen, the attenuation result matrix can be obtained through the arrangement
And 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 health state of the power battery is judged according to the capacity attenuation of the power battery, the health state evaluation result of the power battery is effectively improved, the estimation error caused by the current integral error and the like evaluated by adopting an ampere-hour algorithm in the prior art is avoided, and the accuracy of evaluating the health state of the power battery is effectively improved.
It should be understood that, the sequence numbers of the steps in the foregoing embodiments do not imply an execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.
In one embodiment, a power battery state of health determination device is provided, and the power battery state of health determination device corresponds to the power battery state of health determination method in the above embodiment one to one. As shown in fig. 4, the power battery state of health determination apparatus includes a first obtaining module 101, a second obtaining module 102, a third obtaining module 103, and a fourth obtaining module 104. The functional modules are explained in detail as follows:
the first obtaining module 101 is 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 change rate according to the first SOC in real time;
the second obtaining module 103 is used for obtaining 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 second SOC in real time;
a third determining module 105, configured to determine a capacity attenuation amount of the power battery according to the first SOC change rate and the second SOC change rate;
and the fourth determination module is used for determining the health state of the power battery according to the capacity attenuation amount.
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 constructed in advance to serve 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 real-time first SOC of the power battery 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 real-time second SOC of the power battery through a preset ampere-hour integration algorithm.
The second obtaining module is specifically configured to:
determining the real-time second SOC of the power battery by the following equation:
SOC2＝SOC0-IA/C；
therein, SOC2Representing said second SOC, SOC0Representing an initial SOC value, η, of the power cell1Representing the coulomb efficiency, eta, of the power cell2The charging and discharging efficiency of the power battery is represented, C represents the total capacity of the power battery, and I represents the battery current of the power battery.
In an embodiment, the third determining module 105 is specifically configured to: and determining the capacity attenuation amount of the power battery through a least square identification method and 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 rates of change of SOC are different;
if the first SOC change rate and the second SOC change rate are different, constructing an SOC estimation equation as follows: SOC1(1+dC)+off＝SOC2；SOC1Representing the first SOC, dC representing the capacity attenuation amount of the power battery, off representing the capacity compensation value of the power battery, and SOC2Representing the second SOC, and C representing the total capacity of the power battery;
constructing an attenuation quantity result matrix according to the SOC estimation equation
bk＝[ΔSOC(1) ΔSOC(2) ... ΔSOC(k)]T；
ΔSOC＝SOC2-SOC1；
Wherein k represents the kth single battery in the power battery;
according to the attenuation quantity result matrix
And acquiring the capacity attenuation amount of the power battery.
Therefore, the embodiment of the invention provides a power battery health state determining device, which is characterized in that two kinds of SOC of a power battery are determined through two different modes, including the SOC obtained by using an accurate battery model, so that the difference of SOC change rates obtained in the two modes can be obtained, the SOC obtained by using the accurate battery model can be used as a reference, the attenuation condition of the capacity of the power battery can be judged, the health state of the battery is obtained finally, the stability and the reliability are higher, the practicability is higher, and the accuracy of health state estimation is improved.
For specific limitations of the power battery state of health determination device, reference may be made to the above limitations of the power battery state of health determination method, which are not described herein again. The modules in the power battery state of health determination device can be implemented in whole or in part by software, hardware and a combination thereof. The modules can be embedded in a hardware form or independent from a processor in the controller, and can also be stored in a memory in the controller in a software form, so that the processor can call and execute operations corresponding to the 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 confirming device comprises a processor, a memory, a network interface and a database which are connected through a system bus. Wherein, the processor of the power battery state of health confirming device is used for providing calculation and control ability. The memory of the power battery state of health determination device comprises 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 operating system and computer programs in the storage medium to run. The computer program is executed by a processor to implement a power battery state of health determination method.
In one embodiment, a power battery state of health determination apparatus is provided, which includes a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor implements the following steps when executing the computer program:
acquiring a real-time first SOC of the power battery according to the 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 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 amount.
In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored which, when executed by a processor, performs the steps of:
acquiring a real-time first SOC of the power battery according to the 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 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 amount.
It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware instructions of a computer program, which can be stored in a non-volatile computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. Any reference to memory, storage, database, or other medium used in the embodiments provided herein may include non-volatile and/or volatile memory, among others. Non-volatile 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 DRAM (SLDRAM), Rambus Direct RAM (RDRAM), direct bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).
It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-mentioned division of the functional units and modules is illustrated, and in practical applications, the above-mentioned function distribution may be performed by different functional units and modules according to needs, that is, the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-mentioned functions.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present 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 solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.
Claims (10)
1. A method for determining the state of health of a power battery is characterized by comprising the following steps:
acquiring a real-time first SOC of the power battery according to the 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 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 amount.
2. The method for determining the state of health of the power battery according to claim 1, wherein the obtaining 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 constructed in advance to serve 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 real-time first SOC of the power battery according to the mapping relation between the open-circuit voltage and the SOC of the power battery.
3. The method for determining the state of health of the power battery according to claim 1, wherein the obtaining the real-time second SOC of the power battery according to the SOC estimation algorithm comprises:
and acquiring the real-time second SOC of the power battery through a preset ampere-hour integration algorithm.
4. The method for determining the state of health of the power battery according to claim 3, wherein the obtaining the real-time second SOC of the power battery through a preset ampere-hour integration algorithm includes:
determining the real-time second SOC of the power battery by the following equation:
SOC2＝SOC0-IA/C；
therein, SOC2Representing said second SOC, SOC0Representing an initial SOC value, η, of the power cell1Representing the coulomb efficiency, eta, of the power cell2The charging and discharging efficiency of the power battery is represented, C represents the total capacity of the power battery, and I represents the battery current of the power battery.
5. The power battery state of health determination method of any of claims 1-4, wherein the determining the capacity fade of the power battery from the first rate of change of SOC and the second rate of change of SOC comprises:
and determining the capacity attenuation amount of the power battery through a least square identification method and the first SOC change rate and the second SOC change rate.
6. The power battery state of health determination method of claim 5, wherein the determining the capacity fade of the power battery by a least squares identification method, the first rate of change of SOC, and the second rate of change of SOC comprises:
determining whether the first and second rates of change of SOC are different;
if the first SOC change rate and the second SOC change rate are different, the following SOC estimation equation is constructed: SOC1(1+dC)+off＝SOC2；SOC1Representing the first SOC, dC representing the capacity attenuation amount of the power battery, off representing the capacity compensation value of the power battery, and SOC2Representing the second SOC, and C representing the total capacity of the power battery;
constructing an attenuation quantity result matrix according to the SOC estimation equation
bk＝[ΔSOC(1) ΔSOC(2)...ΔSOC(k)]T；
ΔSOC＝SOC2-SOC1；
Wherein k represents the kth single battery in the power battery;
according to the attenuation quantity result matrix
And acquiring the capacity attenuation amount of the power battery.
7. A power cell state of health determining apparatus, comprising:
the first acquisition module is used for acquiring a real-time first SOC of the power battery according to the battery equivalent model of the power battery;
the first determining module is used for determining a first SOC change rate according to the real-time first SOC;
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;
the third determination module is used for determining the capacity attenuation amount of the power battery according to the first SOC change rate and the second SOC change rate;
and the fourth determination module is used for determining the health state of the power battery according to the capacity attenuation amount.
8. The power battery state of health determination device of claim 7, wherein the first determination module is specifically configured to:
and determining the capacity attenuation amount of the power battery through a least square identification method and the first SOC change rate and the second SOC change rate.
9. A power cell state of health determination apparatus 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 cell state of health determination method according to any one of claims 1 to 6 when executing the computer program.
10. A readable storage medium, in which a computer program is stored, which, when being executed by a processor, carries out the steps of the method for determining the state of health of a power cell according to any one of claims 1 to 6.
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