CN115343630A - Battery voltage drop identification method of power battery - Google Patents

Battery voltage drop identification method of power battery Download PDF

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Publication number
CN115343630A
CN115343630A CN202211049841.2A CN202211049841A CN115343630A CN 115343630 A CN115343630 A CN 115343630A CN 202211049841 A CN202211049841 A CN 202211049841A CN 115343630 A CN115343630 A CN 115343630A
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China
Prior art keywords
battery
string
voltage difference
vehicle
time
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CN202211049841.2A
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Chinese (zh)
Inventor
徐爱琴
秦李伟
刘舒龙
庞灿
姜点双
刘微
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Anhui Jianghuai Automobile Group Corp
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Anhui Jianghuai Automobile Group Corp
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Priority to CN202211049841.2A priority Critical patent/CN115343630A/en
Publication of CN115343630A publication Critical patent/CN115343630A/en
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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]
    • G01R31/382—Arrangements for monitoring battery or accumulator variables, e.g. SoC
    • G01R31/3835—Arrangements for monitoring battery or accumulator variables, e.g. SoC involving only voltage measurements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4285—Testing apparatus
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/48—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte
    • 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 battery voltage drop identification method of a power battery, which comprises the following steps: recording the voltage of each string of modules at preset time intervals when the vehicle is in a charging mode or a standing mode; calculating the voltage difference value of each string of modules at two adjacent recording moments; judging whether the battery cell corresponding to the current string module is abnormal or not according to the voltage difference value of the current string module at two adjacent recording moments and the voltage difference value of the current string module and other string modules; and if the battery core is abnormal, reporting the failure fault of the battery core. The battery voltage drop identification method of the power battery carries out power battery voltage drop calculation on each string module at preset time intervals, accurately identifies an abnormal failure battery cell and eliminates the possibility of false alarm according to the voltage self-comparison of the string modules at two adjacent recording moments and the voltage difference of other string modules, monitors the state of the battery in the charging or standing process of a vehicle, and reports the serious failure condition of the battery to remote monitoring in time without a sensor or a monitoring board.

Description

Battery voltage drop identification method of power battery
Technical Field
The invention relates to the technical field of power batteries, in particular to a battery voltage drop identification method of a power battery.
Background
In the running process of the electric automobile, the state of a power battery is one of the core factors of the normal running of the electric automobile, if the battery has serious self-discharge or serious electric core failure, the vehicle may have advanced power interruption and serious whole automobile fire catching, and the driving experience and the whole automobile safety are seriously influenced; therefore, it is very important to identify the voltage variation of the battery at any time and monitor the serious self-discharge or failure of the individual battery.
At present, the voltage of a battery pack generally adopts the voltage difference to identify the battery fault, and the identification of a failed battery core mostly adopts the methods of a sensor or a monitoring board and the like to identify an abnormal battery core, and the method has the following two defects: 1) By the formula differential pressure = V max -V min The voltage difference is identified, and only the highest and lowest voltage conditions of the batteries in the battery pack can be fed back; 2) There is a risk of false alarm of smoke or aerogel type sensors and monitoring boards; 3) The cost is high, and each vehicle is nearly 1000 yuan.
Therefore, a method for identifying the battery voltage drop of the power battery is needed.
Disclosure of Invention
The invention aims to provide a battery voltage drop identification method of a power battery, which aims to solve the problems in the prior art, can monitor the state of the battery in the charging or standing process of a vehicle, report the serious failure condition of the battery to remote monitoring in time, process the battery for the first time and does not need a sensor or a monitoring board.
The invention provides a battery voltage drop identification method of a power battery, which comprises the following steps:
recording the voltage of each string of modules at preset time intervals when the vehicle is in a charging mode or a standing mode;
calculating the voltage difference value of each string of modules at two adjacent recording moments;
judging whether the battery cell corresponding to the current string module is abnormal or not according to the voltage difference value of the current string module at two adjacent recording moments and the voltage difference value of the current string module and other string modules at two adjacent recording moments;
and if the battery core is abnormal, reporting the failure fault of the battery core.
The method for identifying the battery voltage drop of the power battery preferably records the voltage of each string of modules at preset time intervals when the vehicle is in a charging mode or a standing mode, and specifically includes:
the vehicle enters a charging mode, and a battery management system is initialized;
after the battery management system is initialized successfully, the battery controller records the voltage of each string of modules at preset time intervals;
the vehicle enters a standing mode, and a battery management system is initialized;
after the battery management system is initialized successfully, the battery controller records the voltage of each string of modules at preset time intervals.
The method for identifying the battery voltage drop of the power battery preferably includes that the battery controller records the voltage of each string of modules at preset time intervals when the vehicle is in a charging mode or a standing mode, and specifically includes:
the vehicle control unit judges whether the vehicle is in a relatively stable state;
if the vehicle is in a relatively stable state, the battery controller records all the string module voltages every 10s, so as to obtain V1 (t) -Vn (t), wherein n represents the number of string modules, vn (t) represents the voltage of the nth string module, t represents the recording time, and t takes the value of 0s,10s, 20s.
The method for identifying the battery voltage drop of the power battery preferably includes the following steps:
and the vehicle control unit judges whether the vehicle is in a relatively stable state or not according to the charging and discharging current and the change condition of the charging and discharging current.
The method for identifying battery voltage drop of a power battery as described above, wherein preferably, the calculating a voltage difference value of each string of modules at two adjacent recording moments specifically includes:
when the vehicle is in a charging mode or a standing mode, the battery controller calculates the voltage difference value of two adjacent recording moments of each string of modules at the time t and the time t-1 to obtain Δ V1 (t) = V1 (t) -V1 (t-1).. And Δ Vn (t) = Vn (t) -Vn (t-1).
The method for identifying battery voltage drop of a power battery as described above, wherein preferably, the determining whether the electric core corresponding to the current string module is abnormal according to the voltage difference of the current string module at two adjacent recording moments and the voltage difference of the current string module and the other string modules at two adjacent recording moments specifically includes:
and when the vehicle is in a slow charging mode, a fast charging mode or a standing mode, judging whether the electric core corresponding to the current string module is abnormal or not according to the voltage difference value of the current string module at two adjacent recording moments and the first voltage difference threshold value in the corresponding mode, and the voltage difference value of the current string module and other string modules at two adjacent recording moments and the second voltage difference threshold value in the corresponding mode.
The method for identifying battery voltage drop of a power battery as described above, wherein preferably, when the vehicle is in a slow charging mode, a fast charging mode, or a standing mode, determining whether an electric core corresponding to the current string module is abnormal according to a voltage difference between two adjacent recording times of the current string module and a first voltage difference threshold in the corresponding mode, and a voltage difference between two adjacent recording times of the current string module and another string module and a second voltage difference threshold in the corresponding mode, specifically includes:
when the vehicle is in a slow charging mode, if the voltage difference value delta Vm (t) of the mth string module at the time t and the time t-1 is less than or equal to-20 mV, and the voltage difference value delta Vm (t) of the mth string module at the time t and the time t-1 and the voltage difference value delta V (t) of all other string modules at the time t and the time t-1 are both less than or equal to-20 mV, judging that the battery cell corresponding to the mth string module is abnormal;
when a vehicle is in a fast charging mode, if the voltage difference value delta Vm (t) of the mth string module at the time t and the time t-1 is less than or equal to-50 mV, and the difference values between the voltage difference value delta Vm (t) of the mth string module at the time t and the time t-1 and the voltage difference values delta V (t) of all other string modules at the time t and the time t-1 are less than or equal to-50 mV, judging that the battery cell corresponding to the mth string module is abnormal;
and when the vehicle is in a standing mode, if the charging and discharging current is less than or equal to 2A, the voltage difference value delta Vm (t) of the mth string module at the time t and the time t-1 is less than or equal to-20 mV, and the difference values between the voltage difference value delta Vm (t) of the mth string module at the time t and the time t-1 and the voltage difference values delta V (t) of all other string modules at the time t and the time t-1 are less than or equal to-20 mV, judging that the battery cell corresponding to the mth string module is abnormal.
The method for identifying the battery voltage drop of the power battery, preferably, reporting the battery cell failure fault when the battery cell corresponding to the current string module is abnormal, specifically includes:
the vehicle controller reports a voltage abnormal fault code to a vehicle remote intelligent terminal;
and the whole vehicle remote intelligent terminal pushes the fault information to the remote monitoring system after receiving the fault information.
The invention provides a battery voltage drop identification method of a power battery, in the charging and standing process of a vehicle, voltage drop calculation is carried out on each string of modules at intervals of preset time, whether a battery cell corresponding to a current string module is abnormal or not is judged according to the voltage difference value of the current string module at two adjacent recording moments and the voltage difference value of other string modules, self comparison and mutual comparison are carried out, abnormal and invalid battery cells can be accurately identified, and the possibility of false alarm is eliminated; in the charging process of the vehicle, acquiring the battery information of the vehicle at the relatively stable state moment, thereby calculating the voltage change of the battery; compared with the scheme that only the pressure difference can be simply calculated and a sensor or a monitoring board needs to be matched, the method can more accurately identify the abnormal electric core, save the cost of 1000 yuan/vehicle, facilitate timely treatment and avoid safety accidents.
Drawings
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described with reference to the accompanying drawings, in which:
fig. 1 is a flowchart of an embodiment of a method for identifying a battery voltage drop of a power battery according to the present invention;
FIG. 2 is a voltage distribution curve of 32 strings of modules at time t and time t-1 in the embodiment.
Detailed Description
Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is in no way intended to limit the disclosure, its application, or uses. The present disclosure may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. It should be noted that: the relative arrangement of parts and steps, the composition of materials, numerical expressions and numerical values set forth in these embodiments are to be construed as merely illustrative, and not restrictive, unless specifically stated otherwise.
"first", "second" used in the present disclosure: and the like, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element preceding the word covers the element listed after the word, and does not exclude the possibility that other elements are also covered. "upper", "lower", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.
In the present disclosure, when a specific component is described as being located between a first component and a second component, there may or may not be intervening components between the specific component and the first component or the second component. When it is described that a specific component is connected to other components, the specific component may be directly connected to the other components without having an intervening component, or may be directly connected to the other components without having an intervening component.
All terms (including technical or scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs unless specifically defined otherwise. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate.
At present, the voltage of a battery pack generally adopts the voltage difference to identify the battery fault, and the identification of a failed battery core mostly adopts the methods of a sensor or a monitoring board and the like to identify an abnormal battery core, and the method has the following defects:
1) Excessive dynamic pressure difference in use
The using process refers to that the Battery pack is in a charging or discharging process, after a Battery Management System (BMS) is initialized successfully, the charging and discharging current at the moment is identified, and different differential pressure thresholds are set according to the current and the temperature of the Battery pack.
2) Excessive static pressure difference
After the BMS is initialized successfully, the charging and discharging current is less than or equal to 5A, and the detection is finished within 5s, and different pressure difference thresholds are set according to the electric quantity of a battery pack, the standing time and the temperature of the battery pack because the voltage curves of different types of batteries are different.
3) The aerogel thermal runaway sensor or the monitoring board of the power battery is used for monitoring the judgment of gas or dust and the like in a battery pack, the monitoring board judges through judging an open circuit signal, and once the gas concentration reaches a threshold value or the monitoring board opens a circuit, the signal is reported, so that the risk of false alarm is caused.
As shown in fig. 1, in an actual implementation process, the method for identifying a battery voltage drop of a power battery provided in this embodiment specifically includes the following steps:
and S1, recording the voltage of each string of modules at preset time intervals when the vehicle is in a charging mode or a standing mode.
In an embodiment of the method for identifying a battery voltage drop of a power battery according to the present invention, the step S1 may specifically include:
step S11, the vehicle enters a charging mode, and initializes a Battery Management System (BMS).
And S12, after the Battery Management System (BMS) is initialized successfully, the battery controller (LBC) records the voltage of each string of modules at preset time intervals.
And step S13, the vehicle enters a standing mode, and a Battery Management System (BMS) is initialized.
And S14, after the Battery Management System (BMS) is initialized successfully, the battery controller (LBC) records the voltage of each string of modules at preset time intervals.
Specifically, when the vehicle is in the charging mode or the standing mode, the steps S12 and S14 may specifically include:
and step A, the vehicle control unit judges whether the vehicle is in a relatively stable state.
Specifically, the vehicle control unit judges whether the vehicle is in a relatively stable state according to the charging and discharging current and the change condition of the charging and discharging current.
And step B, if the vehicle is in a relatively stable state, the battery controller (LBC) records all string module voltages at intervals of 10s to obtain V1 (t) -Vn (t), wherein n represents the number of string modules, vn (t) represents the voltage of the nth string module, t represents the recording time, and t is 0s,10s and 2 s.
It should be noted that the preset time interval and the initial recording time are not specifically limited in the present invention. In addition, the number of string modules is not particularly limited in the present invention.
And S2, calculating the voltage difference value of each string of modules at two adjacent recording moments.
Specifically, when the vehicle is in a charging mode or a standing mode, the battery controller (LBC) calculates the voltage difference value of each string of modules at two adjacent recording moments at the t moment and the t-1 moment to obtain Δ V1 (t) = V1 (t) -V1 (t-1).. DELTA Vn (t) = Vn (t) -Vn (t-1).
And S3, judging whether the electric core corresponding to the current string module is abnormal or not according to the voltage difference value of the current string module at two adjacent recording moments and the voltage difference value of the current string module and other string modules at two adjacent recording moments.
Specifically, when the vehicle is in a slow charging mode, a fast charging mode or a standing mode, whether the electric core corresponding to the current string module is abnormal or not is judged according to the magnitude of the voltage difference value of the current string module at two adjacent recording moments and the magnitude of the first voltage difference threshold value in the corresponding mode, and the magnitude of the voltage difference value of the current string module and other string modules at two adjacent recording moments and the magnitude of the second voltage difference threshold value in the corresponding mode.
In an embodiment of the method for identifying a battery voltage drop of a power battery according to the present invention, the step S3 may specifically include:
and S31, under the slow charging mode of the vehicle, if the voltage difference value delta Vm (t) of the mth string module at the time t and the time t-1 is less than or equal to-20 mV, and the voltage difference value delta Vm (t) of the mth string module at the time t and the time t-1 and the voltage difference value delta V (t) of all other string modules at the time t and the time t-1 are less than or equal to-20 mV, judging that the battery cell corresponding to the mth string module is abnormal.
And S32, under the condition that the vehicle is in a quick charging mode, if the voltage difference value delta Vm (t) of the mth string module at the time t and the time t-1 is smaller than or equal to minus 50mV, and the voltage difference value delta Vm (t) of the mth string module at the time t and the time t-1 and the voltage difference value delta V (t) of all other string modules at the time t and the time t-1 are smaller than or equal to minus 50mV, judging that the electric core corresponding to the mth string module is abnormal.
And S33, in a standing mode of the vehicle, if the charging and discharging current is less than or equal to 2A, the voltage difference value delta Vm (t) of the mth string module at the time t and the time t-1 is less than or equal to-20 mV, and the difference values between the voltage difference value delta Vm (t) of the mth string module at the time t and the time t-1 and the voltage difference values delta V (t) of all other string modules at the time t and the time t-1 are less than or equal to-20 mV, judging that the battery cell corresponding to the mth string module is abnormal.
It should be noted that, the present invention does not specifically limit the magnitudes of the first voltage difference threshold and the second voltage difference threshold corresponding to each of the slow charge mode, the fast charge mode, and the rest mode, and the charge/discharge current determination condition in the rest mode.
And S4, reporting a battery cell failure fault if the battery cell is abnormal.
In an embodiment of the method for identifying a battery voltage drop of a power battery according to the present invention, the step S4 may specifically include:
and S41, reporting a voltage abnormal fault code to a vehicle remote intelligent Terminal (TBOX) by a Vehicle Control Unit (VCU).
And S42, the vehicle remote intelligent Terminal (TBOX) pushes the fault information to a remote monitoring system after receiving the fault information.
The long-range intelligent terminal of whole car promotes fault information propelling movement to remote monitering system, reminds the user to cut off the power supply, and the service portion of simultaneously noticing is handled very first time, because of the positive pole material of lithium iron phosphate battery is olivine structure, compares with ternary battery, and its thermal stability is good, and the inefficacy energy of low capacity lithium iron phosphate battery is low, therefore single electric core inefficacy has enough long time to handle.
In an implementation mode, taking a certain type of lithium iron battery pure electric car as an example, the invention applies a plurality of parallel and multi-string battery packs of square battery cells, and the battery voltage drop identification method of the power battery comprises the following steps:
1) The vehicle enters a slow charging mode;
2) The method comprises the following steps that a Vehicle Control Unit (VCU) continuously judges whether a vehicle is in a relatively stable state, for example, the charging current is 7A-8A, and the current change delta I of a battery is less than or equal to +/-1A;
3) After the vehicle is in a relatively stable state, the battery controller (LBC) records all the string module voltages every 10s, namely t0=0s, t1=10s, t2=20s, and records the voltages of all the string modules at the time t as V1 (t) -Vn (t);
4) The battery controller (LBC) calculates the voltage difference value of all the string modules at the time t and the time t-1, namely delta V1 (t) = V1 (t) -V1 (t-1). -, and delta Vn (t) = Vn (t) -Vn (t-1);
5) As shown in fig. 2, Δ V32 (t) = V32 (t) -V32 (t-1) = -24mV, and the difference between Δ V32 (t) and all other Δ V (t) is less than or equal to-20 mV;
6) And (3) the Vehicle Control Unit (VCU) judges that the battery cell in the 32-string module is abnormal and is possibly abnormally invalid, and immediately reports the abnormal battery cell to remote monitoring processing.
According to the battery voltage drop identification method for the power battery, provided by the embodiment of the invention, in the vehicle charging and standing processes, voltage drop calculation is carried out on each string of modules at preset time intervals, whether the electric core corresponding to the current string module is abnormal or not is judged according to the voltage difference value of the current string module at two adjacent recording moments and the voltage difference value of the current string module and the voltage difference value of other string modules, self comparison and mutual comparison are carried out, abnormal and invalid electric cores can be accurately identified, and the possibility of false alarm is eliminated; in the charging process of the vehicle, acquiring the battery information of the vehicle at the relatively stable state moment, thereby calculating the voltage change of the battery; compared with the scheme that only the pressure difference can be simply calculated and a sensor or a monitoring board needs to be matched, the method can more accurately identify the abnormal electric core, save the cost of 1000 yuan/vehicle, facilitate timely treatment and avoid safety accidents.
Thus, various embodiments of the present disclosure have been described in detail. Some details that are well known in the art have not been described in order to avoid obscuring the concepts of the present disclosure. It will be fully apparent to those skilled in the art from the foregoing description how to practice the presently disclosed embodiments.
Although some specific embodiments of the present disclosure have been described in detail by way of example, it should be understood by those skilled in the art that the foregoing examples are for purposes of illustration only and are not intended to limit the scope of the present disclosure. It will be understood by those skilled in the art that various changes may be made in the above embodiments or equivalents may be substituted for elements thereof without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims (8)

1. A battery voltage drop identification method of a power battery is characterized by comprising the following steps:
recording the voltage of each string of modules at preset time intervals when the vehicle is in a charging mode or a standing mode;
calculating the voltage difference value of each string of modules at two adjacent recording moments;
judging whether the battery cell corresponding to the current string module is abnormal or not according to the voltage difference value of the current string module at two adjacent recording moments and the voltage difference value of the current string module and other string modules at two adjacent recording moments;
and if the battery core is abnormal, reporting the failure fault of the battery core.
2. The method for identifying the battery voltage drop of the power battery according to claim 1, wherein the recording the voltage of each string of modules at preset time intervals when the vehicle is in a charging mode or a standing mode specifically comprises:
the vehicle enters a charging mode, and a battery management system is initialized;
after the battery management system is initialized successfully, the battery controller records the voltage of each string of modules at preset time intervals;
the vehicle enters a standing mode, and a battery management system is initialized;
and after the battery management system is successfully initialized, the battery controller records the voltage of each string of modules at preset time intervals.
3. The method for identifying the battery voltage drop of the power battery according to claim 2, wherein when the vehicle is in a charging mode or a standing mode, the battery controller records the voltage of each string of modules at preset time intervals, and specifically comprises:
the vehicle control unit judges whether the vehicle is in a relatively stable state;
if the vehicle is in a relatively stable state, the battery controller records all string module voltages every 10s, obtaining V1 (t) -Vn (t), wherein n represents the number of string modules, vn (t) represents the voltage of the nth string module, t represents the recording time, and t has a value of 0s,10s, and 20s.
4. The method for identifying the battery voltage drop of the power battery according to claim 3, wherein the vehicle controller judges whether the vehicle is in a relatively stable state, and specifically comprises:
and the vehicle controller judges whether the vehicle is in a relatively stable state according to the charging and discharging current and the change condition of the charging and discharging current.
5. The method for identifying the battery voltage drop of the power battery according to claim 3, wherein the step of calculating the voltage difference value of each string of modules at two adjacent recording moments specifically comprises the following steps:
when the vehicle is in a charging mode or a standing mode, the battery controller calculates the voltage difference value of two adjacent recording moments of each string of modules at the time t and the time t-1 to obtain Δ V1 (t) = V1 (t) -V1 (t-1).. And Δ Vn (t) = Vn (t) -Vn (t-1).
6. The method for identifying the battery voltage drop of the power battery according to claim 1, wherein the determining whether the electric core corresponding to the current string module is abnormal according to the voltage difference of the current string module at two adjacent recording moments and the voltage difference of the current string module and the other string modules at two adjacent recording moments specifically comprises:
and when the vehicle is in a slow charging mode, a fast charging mode or a standing mode, judging whether the electric core corresponding to the current string module is abnormal or not according to the voltage difference value of the current string module at two adjacent recording moments and the first voltage difference threshold value in the corresponding mode, and the voltage difference value of the current string module and other string modules at two adjacent recording moments and the second voltage difference threshold value in the corresponding mode.
7. The method for identifying battery voltage drop of a power battery according to claim 6, wherein when a vehicle is in a slow charging mode, a fast charging mode, or a standing mode, whether a cell corresponding to a current string module is abnormal is determined according to a voltage difference between two adjacent recording times of the current string module and a first voltage difference threshold in the corresponding mode, and according to a voltage difference between two adjacent recording times of the current string module and another string module and a second voltage difference threshold in the corresponding mode, and specifically includes:
when the vehicle is in a slow charging mode, if the voltage difference value delta Vm (t) of the mth string module at the time t and the time t-1 is less than or equal to-20 mV, and the voltage difference value delta Vm (t) of the mth string module at the time t and the time t-1 and the voltage difference value delta V (t) of all other string modules at the time t and the time t-1 are both less than or equal to-20 mV, judging that the battery cell corresponding to the mth string module is abnormal;
when a vehicle is in a fast charging mode, if the voltage difference value delta Vm (t) of the mth string module at the time t and the time t-1 is less than or equal to-50 mV, and the difference values between the voltage difference value delta Vm (t) of the mth string module at the time t and the time t-1 and the voltage difference values delta V (t) of all other string modules at the time t and the time t-1 are less than or equal to-50 mV, judging that the battery cell corresponding to the mth string module is abnormal;
and when the vehicle is in a standing mode, if the charging and discharging current is less than or equal to 2A, the voltage difference value delta Vm (t) of the mth string module at the time t and the time t-1 is less than or equal to-20 mV, and the difference values between the voltage difference value delta Vm (t) of the mth string module at the time t and the time t-1 and the voltage difference values delta V (t) of all other string modules at the time t and the time t-1 are less than or equal to-20 mV, judging that the battery cell corresponding to the mth string module is abnormal.
8. The method for identifying the battery voltage drop of the power battery according to claim 1, wherein reporting the failure fault of the battery core when the battery core corresponding to the current string module is abnormal specifically comprises:
the vehicle controller reports a voltage abnormal fault code to a vehicle remote intelligent terminal;
and the whole vehicle remote intelligent terminal pushes the fault information to the remote monitoring system after receiving the fault information.
CN202211049841.2A 2022-08-30 2022-08-30 Battery voltage drop identification method of power battery Pending CN115343630A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116387651A (en) * 2023-05-26 2023-07-04 江苏正力新能电池技术有限公司 Early warning method and system for cell decline in battery pack and maintenance method of battery pack

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116387651A (en) * 2023-05-26 2023-07-04 江苏正力新能电池技术有限公司 Early warning method and system for cell decline in battery pack and maintenance method of battery pack
CN116387651B (en) * 2023-05-26 2023-08-11 江苏正力新能电池技术有限公司 Early warning method and system for cell decline in battery pack and maintenance method of battery pack

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