CN113219351B - Monitoring method and device for power battery - Google Patents
Monitoring method and device for power battery Download PDFInfo
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- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
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Abstract
The invention provides a monitoring method and a monitoring device for a power battery, wherein the method comprises the following steps: acquiring at least one of charging data, discharging data and temperature data of the power battery cluster and capacity data; determining an abnormal electric core from the power battery cluster based on at least one of charging data, discharging data and temperature data of the power battery cluster; determining the internal resistance of the abnormal electric core; determining a charging capacity value of a target power battery based on the capacity data of the target power battery where the abnormal battery cell is located; and determining the battery health state of the target power battery based on the internal resistance and the charging capacity value. The monitoring method of the power battery provided by the invention reduces the influence of capacity error and temperature on the calculation of the health state of the battery, improves the accuracy of the health state of the battery, and is beneficial to more accurately evaluating the service life of the power battery.
Description
Technical Field
The invention relates to the technical field of power batteries, in particular to a monitoring method and a monitoring device for a power battery.
Background
The power battery is a power source of an electric vehicle, and common batteries include lead-acid batteries, lithium iron phosphate batteries and the like. The state of health of a power battery is an important evaluation parameter that affects the service life of the power battery and an electric vehicle. The existing method for calculating the health state of the power battery mainly comprises the steps of fully charging the power battery, reading and calculating capacity information of the power battery through a Battery Management System (BMS), calculating the health state of the power battery, and further predicting the service life of the power battery. Due to the fact that certain errors exist in reading and calculating capacity information of the power battery by the BMS, the calculation result of the health state of the power battery is inaccurate, and the service life of the power battery cannot be accurately evaluated.
Disclosure of Invention
The invention provides a monitoring method and a monitoring device for a power battery, which are used for solving the defect of inaccurate calculation of the health state of the power battery in the prior art.
The invention provides a monitoring method of a power battery, which comprises the following steps: acquiring at least one of charging data, discharging data and temperature data of the power battery cluster and capacity data;
determining an abnormal electric core from the power battery cluster based on at least one of charging data, discharging data and temperature data of the power battery cluster;
determining the internal resistance of the abnormal electric core;
determining a charging capacity value of a target power battery based on the capacity data of the target power battery where the abnormal battery cell is located;
and determining the battery health state of the target power battery based on the internal resistance and the charging capacity value.
According to the monitoring method of the power battery provided by the invention, the determining of the internal resistance of the abnormal battery cell comprises the following steps:
controlling the current magnitude to be target current through a class balancing circuit, and determining the direct current internal resistance of the abnormal electric core based on the target current;
wherein the class equalization circuit comprises: and the DC/DC module is electrically connected with each battery cell end to end and is connected with pulse current.
According to the monitoring method of the power battery provided by the invention, the determining the charging capacity value of the target power battery based on the capacity data of the target power battery where the abnormal battery core is located includes:
acquiring the pre-charging electric quantity and the post-charging electric quantity of the target power battery;
and determining the charging capacity value of the target power battery based on the pre-charging electric charge quantity, the post-charging electric charge quantity and the charging electric charge quantity.
The method for monitoring a power battery according to the present invention, wherein the determining the charge capacity value of the target power battery based on the pre-charge amount, the post-charge amount, and the charge amount includes:
using formulae
Cap＝AmpHrs/(SOC2-SOC1)
Determining the charge capacity value;
wherein Cap is the charging capacity value, ampHrs is the charging capacity, SOC2 is the post-charging charge, and SOC1 is the pre-charging charge.
According to the monitoring method of the power battery provided by the invention, the determining the battery health state of the target power battery based on the internal resistance and the charging capacity value comprises the following steps:
using formulas
HVBatSOH＝kCAP*(Cap/CAPBOL)-kRd*(DCRL/DCRL0)+koffset
Determining the battery state of health;
the HVBatSOH is the battery health state, the kCAP is a capacity correction parameter of the target power battery, kRd is an internal resistance correction parameter of the target power battery, koffset is a service life correction parameter of the target power battery, CAPBOL is an initial capacity value of the target power battery, cap is the charge capacity value, DCRL is the internal resistance, and DCRL0 is the initial internal resistance of the abnormal battery cell.
According to the monitoring method of the power battery provided by the invention, based on at least one of the charging data, the discharging data and the temperature data of the power battery cluster, an abnormal battery cell is determined from the power battery cluster, and the monitoring method comprises the following steps:
determining the target power battery from the power battery cluster, wherein the target power battery is provided with the abnormal battery core.
According to the invention, a monitoring method of a power battery is provided,
acquiring the balancing time of all power batteries in the power battery cluster; the determining the target power battery from the power battery cluster comprises:
acquiring the balancing time of all power batteries in the power battery cluster;
determining the target power battery from the power battery cluster, wherein the number of times that the balance time length of the target power battery is greater than the target time length is greater than a first target number of times;
or,
acquiring a low-voltage current value of the operation of all power batteries in the power battery cluster under the condition that the voltage of all power batteries is lower than a preset low voltage;
determining the target power battery from the power battery cluster, wherein the times that the low-voltage current value of the target power battery is larger than a first preset current value are larger than a second target times;
or,
acquiring a high-voltage current value of charging of all power batteries in the power battery cluster under the condition that the voltage of all power batteries is higher than a preset high voltage;
determining the target power battery from the power battery cluster, wherein the number of times that the high-voltage current value of the target power battery is greater than a second preset current value is greater than a third target number of times;
or,
acquiring a first load current value of all power batteries in the power battery cluster and a second load current value of charging under a normal working condition;
determining the target power battery from the power battery cluster, wherein the times that the first load current value of the target power battery is larger than a third preset current value are larger than a fourth target times, and/or the times that the second load current value of the target power battery is smaller than a fourth preset current value are larger than a fifth target times;
or,
acquiring the battery temperature of all power batteries in the power battery cluster;
and determining the target power battery from the power battery cluster, wherein the times that the battery temperature of the target power battery is higher than the target temperature are higher than a sixth target time. According to the monitoring method of the power battery provided by the invention, based on at least one of the charging data, the discharging data and the temperature data of the power battery cluster, an abnormal battery core is determined from the power battery cluster, and the monitoring method further comprises the following steps:
under the condition that the target power battery is fully charged, acquiring the charging stable voltage of all battery cores in the target power battery;
determining the abnormal cell from all the cells based on the charging stabilization voltage;
or,
after the target power battery runs for a preset time, acquiring discharge stable voltages of all battery cores in the target power battery;
determining the abnormal cell from the all cells based on the discharge stabilization voltage.
The invention provides a monitoring method of a power battery, which further comprises the following steps:
the P cells with the highest cell voltage in the charging stable voltages of all the cells are determined, and if the charging stable voltage of a certain cell is always located at the front P position, the cell is the abnormal cell;
wherein N is more than P and is more than or equal to 1,N is the number of all the battery cells;
or,
the lowest cell voltage of the discharge stable voltages of all the cells is Q, and if the charge stable voltage of a certain cell is always in the rear Q position, the cell is the abnormal cell;
wherein N is more than Q and is more than or equal to 1,N is the number of all the battery cells.
The invention also provides a monitoring device of the power battery, which comprises: the acquisition module is used for acquiring at least one of charging data, discharging data and temperature data of the power battery cluster and capacity data;
the determining module is used for determining an abnormal battery cell from the power battery cluster based on at least one of charging data, discharging data and temperature data of the power battery cluster;
the first calculation module is used for determining the internal resistance of the abnormal battery cell;
the second calculation module is used for determining a charging capacity value of a target power battery based on the capacity data of the target power battery where the abnormal battery core is located;
the third calculation module is used for determining the battery health state of the target power battery based on the internal resistance and the charging capacity value;
the monitoring device of the power battery is used for realizing the monitoring method of the power battery.
The invention also provides an electronic device, which comprises a memory, a processor and a computer program stored on the memory and capable of running on the processor, wherein the processor executes the program to realize the steps of the monitoring method of the power battery.
The invention also provides a non-transitory computer-readable storage medium having stored thereon a computer program which, when executed by a processor, carries out the steps of the method of monitoring a power cell as described in any one of the above.
According to the monitoring method and device for the power battery, provided by the invention, the abnormal electric core is screened out through the analysis of the historical data of the power battery, the health state of the battery is determined based on the internal resistance and the charging capacity value, the influence of capacity errors and temperature on the calculation of the health state of the battery is reduced, the accuracy of the health state of the battery is improved, and the service life of the power battery is more accurately evaluated.
Drawings
In order to more clearly illustrate the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a schematic flow chart of a monitoring method for a power battery provided by the present invention;
FIG. 2 is a circuit diagram of a class equalization circuit provided in the present invention;
fig. 3 is a schematic diagram illustrating determination of an abnormal cell according to the present invention;
FIG. 4 is a schematic flow chart of the present invention for determining the state of health of a battery;
FIG. 5 is a schematic structural diagram of a monitoring device for a power battery provided by the present invention;
fig. 6 is a schematic structural diagram of an electronic device provided in the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention.
The monitoring method of the power battery of the present invention is described below with reference to fig. 1 to 3. The execution main body of the method can be a monitor of a device end, or a cloud end, or an edge server.
The power battery is a power supply for providing a power source for tools, and is a storage battery for providing power for electric automobiles, electric trains, electric bicycles and electric operation machines.
The types of power batteries include lead-acid batteries, ternary lithium batteries, lithium iron phosphate batteries and the like.
The power battery comprises a battery core and a protection circuit board, wherein the battery core is an electric storage part in the power battery, the quality of the battery core directly determines the quality of the power battery, and the protection circuit board is an integrated circuit which plays a role in protection in the power battery.
The Battery Management System (BMS), also called a battery caregiver or a battery manager, is used for intelligently managing and maintaining the power battery, preventing the power battery from being overcharged and overdischarged, prolonging the service life of the power battery, and monitoring the state of the power battery.
The states of the power battery monitored by the BMS include: cell voltage, energy balance among cells, total battery voltage, total battery current, state of charge (SOC) of the battery, and operating state of the battery.
BMS still is used for carrying out real-time data display, record and analysis to the power battery's of control state, and BMS still has communication function, can transmit the power battery's of control state to high in the clouds or marginal server.
As shown in fig. 1, the monitoring method for a power battery provided by the present invention includes: step 110 and step 150.
And step 110, acquiring at least one of charging data, discharging data and temperature data of the power battery cluster and capacity data.
The power battery cluster comprises a plurality of power batteries, and the plurality of power batteries can be distributed on different electric tools or can be a plurality of power batteries on the same electric tool.
And acquiring the charging data, the discharging data, the temperature data and the capacity data of each power battery in the power battery cluster through the BMS.
The charging data of the power battery is battery performance data of the power battery in the charging process, and comprises data of voltage, current, temperature and the like in the charging process.
The discharge data of the power battery is battery performance data of the power battery in a discharge process, namely an operation process of the power battery, and comprises data such as voltage, current, temperature and the like of the power battery in operation.
The temperature data of the power battery are the battery temperature and the ambient temperature of the power battery, and the battery temperature is also related to the running condition of the power battery and the thermal management of the power battery besides the ambient temperature.
The capacity data of the power battery is battery capacity data of the power battery, and the battery capacity represents the electric quantity discharged by the power battery under the condition of a certain discharge rate, temperature or termination voltage.
Battery capacity is an important performance indicator that measures battery performance, usually in ampere hours (Ah).
The capacity data of the power battery can be divided into actual capacity, theoretical capacity and rated capacity according to different conditions.
For example, the rated capacity of the battery is 1300mAh, i.e., the battery can continue to operate for 10 hours with a current of 130mA discharging the battery.
The BMS is used for acquiring the relevant data of each power battery in the power battery cluster, and during specific implementation, the BMS can acquire at least one of the charging data, the discharging data and the temperature data of the power battery cluster and capacity data, and can also acquire the charging data, the discharging data, the temperature data and the capacity data of the power battery cluster at the same time.
The charging data, the discharging data, the temperature data and the capacity data of each power battery in the power battery cluster are obtained, the state of each power battery can be monitored according to the related data of each power battery, and the power batteries can be maintained in time.
And step 120, determining an abnormal electric core from the power battery cluster based on at least one of the charging data, the discharging data and the temperature data of the power battery cluster.
Consistency is one of the expression forms of power batteries, and mainly refers to the difference of parameters such as voltage, charge, capacity and decay rate thereof, internal resistance and change rate thereof, service life, temperature, self-discharge rate and the like among all battery cores in one power battery.
When parameters of all battery cores in the power battery have large differences, the power battery shows inconsistency.
The inconsistency of the power battery can lead the running loss of each electric core in the power battery to be different, and the use of the power battery is influenced.
The inconsistency of the power battery is already generated in the production stage, and in the use process, certain measures need to be taken to slow down, such as battery equalization and other measures, so that the further increase of the inconsistency of the power battery is avoided.
The power battery can be kept consistent only when the power battery runs and is charged under normal working conditions.
When the power battery works normally, the running and charging voltage, current, discharging power and battery temperature of the power battery have certain interval ranges.
And based on at least one of the charging data, the discharging data and the temperature data of each power battery of the power battery cluster, the power batteries which normally work and the power batteries which abnormally work can be judged.
The power battery which is abnormally operated shows inconsistency, the battery cell is an electricity storage part in the power battery, and the battery cell in an abnormal state in the power battery is a main factor which causes the power battery to show the inconsistency.
The abnormal cell in the power battery is a short plate of the power battery, and the service life of the abnormal cell is the service life of the power battery.
And judging whether the power battery cluster has the power battery which works abnormally or not according to at least one of the charging data, the discharging data and the temperature data of each power battery in the power battery cluster, and further determining the abnormal battery core.
In specific implementation, whether a certain battery cell is an abnormal battery cell or not can be judged according to the charging data, the discharging data or the temperature data of the certain battery cell and the data difference of other battery cells in the power battery.
The abnormal cells can be screened out by analyzing the charging data, the discharging data or the temperature data of all the cells in the power battery which works abnormally by using a principal component analysis method or a clustering method.
And collecting charging data, discharging data or temperature data of the abnormally working power battery after the power battery runs for a period of time through the BMS, and analyzing and screening the data.
For example, the BMS collects charging data, discharging data, or temperature data after one month of operation of an abnormally operated power battery, and uploads the data to a server platform for analysis.
In the battery of the month, the voltage of the cell No. 7 after being discharged is always the lowest voltage of all the cells after being discharged, or the voltage of the cell No. 7 after being recharged is always the highest voltage of all the cells after being charged, which indicates that the cell No. 7 may be an abnormal cell.
The voltage increase rate of the 7 # battery cell during charging and the voltage decrease rate of the 7 # battery cell during discharging can be further paid attention to, and whether the 7 # battery cell is an abnormal battery cell or not is further judged.
After 7 electric cores are screened out, prompt information and early warning information about 7 electric cores are carried out on the user, and the user can conveniently carry out further detection.
It should be noted that, the determination of whether the battery cell is an abnormal battery cell according to the voltage value of the No. 7 battery cell charging data and the discharging data is only an example, and during actual execution, the temperature data may also be analyzed, which may be specifically determined according to actual needs, and this is not limited in the embodiment of the present invention.
According to at least one of charging data, discharging data and temperature data in the power battery cluster, determining an abnormal battery cell in the power battery cluster, namely a main factor causing inconsistency of the power battery, and facilitating evaluation of the working state of the power battery.
And step 130, determining the internal resistance of the abnormal battery cell.
The abnormal electric core is a short plate of the power battery, and the service life of the abnormal electric core is the service life of the power battery.
The internal resistance of the abnormal cell is a cell performance parameter of the abnormal cell.
The internal resistance of the abnormal cell is direct current internal resistance which is the ratio of the voltage change of the battery to the corresponding discharge current change under the working condition.
The internal resistance of the abnormal cell can be expressed by DCR, which has the unit of ohm (Ω), and can be directly measured by an ohmmeter.
And determining the internal resistance of the abnormal battery cell, and further evaluating the service life and the quality state of the power battery according to the battery cell performance of the abnormal battery cell.
And step 140, determining a charging capacity value of the target power battery based on the capacity data of the target power battery where the abnormal battery core is located.
The target power battery is the power battery screened out in the abnormal working state after being analyzed based on at least one of the charging data, the discharging data and the temperature data of the power battery cluster.
The capacity data of the power battery, namely the state of charge (SOC) of the power battery under charging and running conditions, also called charge amount, is obtained by the BMS, and the state of charge represents the maximum amount of electricity that can be stored in the power battery.
The state of charge is typically the ratio of the current capacity of the power cell to its rated capacity, which can reflect the performance and life of the power cell.
The accuracy of acquiring the capacity data of the power battery through the BMS is not high, and under different application environments, different battery models are required to be adopted for estimating the capacity data.
The charging capacity value of the target power battery is the capacity value of the target power battery charged in the charging process.
The charging capacity value is the difference value of the charging states of the power battery under the charging and running conditions, the error of directly acquiring capacity data through the BMS can be eliminated, and the accuracy of reflecting the performance and the service life of the power battery by using the capacity data of the power battery is improved.
And 150, determining the battery health state of the target power battery based on the internal resistance and the charging capacity value.
Battery state of health (SOH) is the current battery's ability to store electrical energy relative to a new battery, i.e., the state of the battery from the beginning to the end of its life, usually expressed in percentage terms.
The battery temperature, the charge-discharge rate, the discharge depth, the cycle interval, the charge-discharge cut-off voltage and the like of the power battery all affect the health state of the battery.
The battery health state cannot be obtained by direct measurement, and currently, the calculation definition of the battery health state is not uniform, and is generally defined by capacity, electric quantity, internal resistance, cycle number or peak power and the like.
In the related art, the capacity of the battery in the state of health is defined as the ratio of the current capacity of the battery to the rated capacity of the battery, and the battery in the state of health defined by the capacity has low accuracy because a certain error exists in the process of directly obtaining the current capacity of the battery.
In the related art, the electric quantity of the battery health state is defined as the ratio of the current maximum discharge electric quantity of the battery to the new maximum discharge electric quantity of the battery, and is similar to the capacity definition of the battery health state, the electric quantity has a certain error, and the accuracy of the battery health state is low.
In the related art, the internal resistance of the battery in the state of health is defined as the ratio of the difference between the internal resistance at the end of the battery life minus the internal resistance of the current battery and the difference between the internal resistance at the end of the battery life minus the internal resistance of the new battery.
The internal resistance is related to the state of charge and the temperature, is difficult to measure, and the internal resistance definition operability of the battery health state is not strong.
The battery health state of the target power battery is calculated based on the internal resistance of the abnormal electric core and the charging capacity value of the target power battery.
Compared with the calculation of the internal resistance of the battery, the calculation of the internal resistance of the abnormal battery cell is simpler and more convenient, and the influence of the charge state and the temperature on the resistance calculation result can be greatly reduced.
The charging capacity value of the target power battery is the difference value of the charging states of the power battery under the charging and running conditions, and the error of directly acquiring capacity data through the BMS is eliminated.
The battery health state of the target power battery is defined by two performance parameters, namely the internal resistance of the abnormal battery core and the charging capacity value of the target power battery, and is more accurate than the battery health state defined by a single performance parameter.
And determining the battery health state of the target power battery based on the internal resistance of the abnormal battery core and the charging capacity value of the target power battery, and eliminating capacity errors and temperature influences to a certain extent.
According to the monitoring method of the power battery provided by the invention, the abnormal electric core is screened out through the analysis of the historical data of the power battery, the health state of the battery is determined based on the internal resistance and the charging capacity value, the influence of capacity errors and temperature on the calculation of the health state of the battery is reduced, the accuracy of the health state of the battery is improved, and the service life of the power battery is more accurately evaluated.
In some embodiments, determining the internal resistance of the abnormal cell includes: controlling the current magnitude to be a target current through a class balancing circuit, and determining the direct current internal resistance of the abnormal battery cell based on the target current;
wherein, class equalizer circuit includes: and the DC/DC module is electrically connected with each battery cell end to end and is connected with pulse current.
As shown in fig. 2, the equalization-like circuit is of a similar design to the equalization circuit, and each cell of the power battery in the equalization-like circuit has a DC/DC module 22 electrically connected to it.
The input end 21 of the DC/DC module 22 is connected with a pulse current for charging the battery cell.
The DC-DC module 22 performs pulse charging on the battery cell by using an external current, and calculates a direct current internal resistance (DCR) of the abnormal battery cell 23 according to the charged voltage difference and current.
In practical implementation, the input end 21 of the DC/DC module 22 is controlled to be connected to a pulse current of a target current, the magnitude of the target current is selected according to the cell performance, and preferably, the target current may be 5A.
The abnormal electric core has higher balancing frequency relative to other normal electric cores in the power battery, and the abnormal electric core is charged or discharged through the class balancing circuit, so that the internal resistance measurement state is consistent with the common working condition of the abnormal electric core, and the internal resistance measurement accuracy is improved.
It should be noted that the class balancing circuit is not used for balancing the power battery, but is only used for calculating the internal resistance of the abnormal battery cell in the target power battery.
Through class equalizer circuit, it is higher to measure the internal resistance degree of accuracy of unusual electric core under the common operating mode of unusual electric core, the reflection electric core performance that can be more accurate.
In some embodiments, the pre-charge and post-charge of the target power battery are obtained; and determining the charging capacity value of the target power battery based on the pre-charging electric quantity, the post-charging electric quantity and the charging electric quantity.
The state of charge of the power battery under the charging and running conditions is acquired through the BMS, and the state of charge of the target power battery before charging, namely the charging amount before charging, and the state of charge of the target power battery after completing charging, namely the charging amount after charging are acquired.
The charging electric quantity is the electric quantity output by the charger when the target power battery is connected with the charger for charging, and the charging electric quantity can be read by the charger and also can be read by the BMS.
According to the pre-charging electric quantity, the post-charging electric quantity and the charging electric quantity, the error of directly acquiring the state of charge through the BMS is eliminated, and the capacity value of the target power battery charged in the charging process can be accurately calculated.
In specific implementation, the formula is applied
Cap＝AmpHrs/(SOC2-SOC1)
And determining a charging capacity value, wherein Cap is the charging capacity value, ampHrs is the charging capacity, SOC2 is the charged capacity after charging, and SOC1 is the charged capacity before charging.
In the following description of a specific example, the capacity data of the target power battery obtained by the BMS is shown in table 1.
The charge capacity value is calculated from the capacity data in table 1, the pre-charge amount of charge SOC1, the post-charge amount of charge SOC2, and the charge amount of charge AmpHrs.
As shown in table 1, ampHrs is 11ah, soc2 is 91.8%, SOC1 is 7.1%, cap = AmpHrs/(SOC 2-SOC 1) =11 Ah/(91.8% -7.1%) =12.98Ah, and the obtained charge capacity value of the abnormal cell is 12.98Ah.
TABLE 1
| Item | Value of | Unit of |
| State of charge | Non-inserted charging gun | |
| Accumulated mileage data before charging | 99835 | km |
| Charging duration inserted into charging gun | 2771 | seconds |
| Charging capacity AmpHrs | 11 | Ah |
| Charge SOC1 before charging | 7.1 | ％ |
| Charged amount SOC2 after charging | 91.8 | ％ |
| Highest cell voltage after charging | 4107 | mv |
| Lowest cell voltage after charging | 4123 | mv |
| Cell voltage difference after charging | 16 | mv |
It should be noted that, the target power battery needs to be left standing for a period of time, and then the charged capacity data of the target power battery is read, so as to improve the accuracy of the acquired capacity data.
In some embodiments, the battery state of health of the target power battery is determined based on the internal resistance and charge capacity values, and a formula is applied
HVBatSOH＝kCAP*(Cap/CAPBOL)-kRd*(DCRL/DCRL0)+koffset
And determining the battery health state of the target power battery, wherein HVBatSOH is the battery health state, kCAP is a capacity correction parameter of the target power battery, kRd is an internal resistance correction parameter of the target power battery, koffset is a service life correction parameter of the target power battery, CAPBOL is an initial capacity value of the target power battery, cap is a charging capacity value, DCRL is an internal resistance, and DCRL0 is an initial internal resistance of an abnormal battery core.
kCAP, kRd, koffset is a calibrated parameter, and a corresponding specific value can be obtained only through a test of a target power battery.
CAPBOL is the initial capacity value of the target power battery and is the test capacity value of the target power battery when the target power battery leaves the factory.
The DCRL0 is the initial internal resistance of the abnormal electric core, and is the direct current internal resistance value obtained by testing the abnormal electric core of the target power battery when the battery leaves the factory.
Based on the internal resistance of the abnormal electric core and the charging capacity value of the target power battery, the battery health state obtained by calculation is combined, the capacity error and the temperature influence are eliminated to a certain extent, and the service life of the power battery can be more accurately evaluated.
In some embodiments, after determining the battery health status of the target power battery based on the internal resistance and the charging capacity value, the battery health status of the target power battery and the battery data of the abnormal battery cell may be sent to the user.
After the battery health state of the target power battery is determined, an early warning threshold value of the battery health state can be set, and when the battery health state reaches or exceeds the early warning threshold value, early warning is carried out to monitor the battery health state in time.
In some embodiments, a target power cell is determined from a power cell cluster; determining internal resistances of all battery cores in the target power battery; and determining an abnormal cell from the cells of the target power battery based on the internal resistances of all the cells in the target power battery.
After the target power battery is determined, the charging data, the discharging data or the temperature data of all the battery cores in the target power battery can be analyzed by using a principal component analysis method or a clustering method, and the battery core with larger difference with the battery core performance data of other battery cores, namely an abnormal battery core, is screened out.
After the target power battery is determined, the internal resistances of all the battery cores in the target power battery can be obtained, and abnormal battery cores with larger internal resistance difference with other battery cores are screened.
In specific implementation, the internal resistances of all the battery cores in the target power battery can be obtained by using the class equalizing circuit, and the average value and the variance of the internal resistances of all the battery cores are obtained.
When the difference between the internal resistance of the battery cell of a certain battery cell and the average value is large or the variance is large, the battery cell can be determined to be an abnormal battery cell.
In specific implementation, after the internal resistances of all the battery cells in the target power battery are obtained by using the class equalizing circuit, the internal resistance data of all the battery cells are screened by using a data analysis method such as a principal component analysis method or a clustering method.
The discrete degree of the internal resistance of the battery cell of a certain battery cell relative to the internal resistances of the battery cells of other battery cells is large, and the battery cell can be determined to be an abnormal battery cell.
And determining a target power battery from the power battery cluster, and determining an abnormal battery core from the battery cores of the target power battery based on the internal resistance, so that the accurate calculation of the health state of the battery is facilitated, and the service life of the power battery is evaluated.
The following specifically describes the embodiments of the present application from seven different implementation angles, respectively, with reference to fig. 3.
1. And determining the abnormal battery core 30 based on the equalization duration 31 of the power battery.
In the embodiment, the balancing duration of all the power batteries in the power battery cluster is obtained; and determining a target power battery from the power battery cluster, wherein the number of times that the balance time length of the target power battery is greater than the target time length is greater than the first target number.
And after the target power battery is determined according to the balancing duration, determining an abnormal battery cell from the battery cells of the target power battery.
After a period of time, voltages among the battery cells in the power battery are greatly different, and the voltage difference of the battery cells in the power battery in the running state needs to be balanced through the balancing circuit, so that the battery capacity is improved.
And balancing the power battery according to a preset period and the service state of the power battery, wherein the balancing process is a process of charging the power battery, and the balancing time belongs to charging data.
The method comprises the steps of obtaining the balance time of all power batteries in a power battery cluster, wherein the balance time of each power battery is different according to different use states of the power batteries, and the balance time of the same power battery in different stages is different.
Compared with other power batteries without abnormal electric cores, the target power battery with the abnormal electric core has higher balancing frequency and longer balancing time.
When the obtained balancing time of the power battery is longer than the target time, an abnormal electric core may exist in the power battery, so that the balancing time is too long.
In specific implementation, the target duration may be set according to the performance and the use condition of the power battery, for example, the target duration may be 1000 seconds.
When the obtained number of times that the equalization duration of the power battery is greater than the target duration is greater than the first target number, it may be determined that an abnormal electrical core exists in the power battery, where the power battery is a target power battery in a power battery cluster.
In specific implementation, the first target number may be set according to the performance and the use condition of the power battery, for example, the first target number may be 5.
In the following description of a specific embodiment, the equalization duration data of one power battery in the power battery cluster obtained by the BMS is shown in table 2:
TABLE 2
| Equalizing duration (seconds) | Number of equalizations |
| Equalizing duration<＝50 | 50 |
| 50<Equalizing duration<＝100 | 30 |
| 100<Equalizing duration<＝300 | 20 |
| 300<Equalizing duration<＝500 | 10 |
| 500<Equalizing duration<＝1000 | 3 |
| 1000<Equalizing duration | 1 |
As shown in table 2, the number of times that the equalization duration of the power battery is greater than the target duration by 1000 seconds is 1 time, and is less than the first target number of times by 5 times, and the battery performance of the power battery is good, and the power battery is not a target power battery in the power battery cluster.
When the number of times that the balance duration of a certain power battery is greater than the target duration for 1000 seconds is greater than the first target number of times for 5 times, an abnormal electric core exists in the power battery, and the power battery is a target power battery in a power battery cluster.
After the target power battery is determined, the charging data, the discharging data or the temperature data of all the battery cores in the target power battery can be analyzed by a principal component analysis method or a clustering method, and abnormal battery cores with large data difference of other battery cores are screened.
After the target power battery is determined, the internal resistances of all the battery cores in the target power battery can be obtained, and abnormal battery cores with larger internal resistance difference with other battery cores are screened.
2. The abnormal cell 30 is determined based on the low-voltage discharge current 32 of the power battery.
In the embodiment, the running low-voltage current value of all power batteries in the power battery cluster is obtained under the condition that the voltage of all power batteries is lower than the preset low voltage; and determining a target power battery from the power battery cluster, wherein the times that the low-voltage current value of the target power battery is greater than the first preset current value are greater than the second target times.
And after the target power battery is determined based on the low-voltage discharge current, determining an abnormal battery cell from the battery cells of the target power battery.
When the power battery runs under a normal working condition, the running voltage and current of the battery are within a certain range, and the voltage or current exceeding range is the performance of abnormal work of the power battery, which indicates that an abnormal battery core may exist in the power battery at the moment.
Under the condition that the voltage of the power battery is lower than the preset low voltage, the discharge current during operation is the low-voltage current value, and the low-voltage current value belongs to the discharge data of the power battery.
In specific implementation, the preset low voltage may be set according to performance and use condition of the power battery, for example, the preset low voltage may be 220 volts (V) or 240V.
Different preset low-voltage operation conditions are adopted, and the low-voltage current value has different current threshold values, for example, the preset low voltage is 220V, and the first preset current value is 300A (A); the predetermined low voltage is 240V, and the first predetermined current value is 200V.
When the number of times that the low-voltage current value is greater than the first preset current value is greater than the second target number of times, it can be determined that an abnormal electric core exists in the power battery, and the power battery is a target power battery in a power battery cluster.
When the method is specifically implemented, the second target times can be set according to the use condition of the power battery, and the second target times under different preset low-voltage operation conditions are different.
For example, the preset low voltage is 220V, the second target number of times may be 10 times, the preset low voltage is 240V, and the second target number of times may be 15 times.
In the following, a specific embodiment is described, and the low-voltage current value data of one power cell in the power cell cluster is obtained by the BMS, as shown in table 3:
TABLE 3
| Preset low voltage | Low voltage current value>A first preset current value | Number of times |
| 220V | Low voltage current value<＝-300A | 5 |
| 240V | Low voltage current value<＝-200A | 20 |
The current is negative during discharging, and the magnitude of the current is compared with the absolute value of the current value.
In the data of the low voltage current value shown in table 3, under the condition of the preset low voltage smaller than 220V, the number of times that the absolute value of the low voltage current value is larger than the first preset current value 300A appears 5 times and is smaller than 10 times, and no abnormal electric core is found.
Under the condition of the preset low voltage less than 240V, the times that the absolute value of the low-voltage current value is greater than the first preset current value 200A are 20 times and greater than 15 times, an abnormal cell exists in the power battery, and the power battery is a target power battery in the power battery cluster.
And the power battery is subjected to high-current use under the condition of low voltage, the high-current use frequency exceeds a second target frequency, and the power battery is a target power battery in the power battery cluster.
After the target power battery is determined, the charging data, the discharging data or the temperature data of all the battery cores in the target power battery can be analyzed by using a principal component analysis method or a clustering method, and abnormal battery cores with larger data difference from other battery cores are screened.
After the target power battery is determined, the internal resistances of all the battery cores in the target power battery can be obtained, and abnormal battery cores with larger internal resistance difference with other battery cores are screened.
3. The abnormal cell 30 is determined based on the high-voltage charging current 33 of the power battery.
In the embodiment, the charging high-voltage current value of all power batteries in the power battery cluster is obtained under the condition that the charging high-voltage current value is greater than the preset high voltage; and determining a target power battery from the power battery cluster, wherein the times that the high-voltage current value of the target power battery is greater than the second preset current value are greater than a third target time.
When the power battery is charged, the voltage and the current of the power battery are also within a certain range, and the voltage or the current exceeding the range is the expression that abnormal cells possibly exist in the power battery.
When the voltage of the power battery is higher than the preset high voltage, the discharge current during operation is the high voltage current value, and the high voltage current value belongs to the charging data of the power battery.
The preset high voltage is similar to the preset low voltage and can be set according to the performance and the use working condition of the power battery.
When charging is performed in different environments with preset high voltages, the high voltage current value has different current thresholds along with different preset high voltages, that is, different preset high voltages correspond to different second preset current values.
When the number of times that the high-voltage current value is greater than the second preset current value is greater than a third target number of times, it can be determined that an abnormal electric core exists in the power battery, and the power battery is a target power battery in a power battery cluster.
In specific implementation, the third target number may be set according to the usage condition of the power battery, for example, the third target number may be 10.
When the power battery is charged in a high-voltage environment, the charging times of the large current exceed the third target times, and the power battery is a target power battery in the power battery cluster.
After the target power battery is determined, the charging data, the discharging data or the temperature data of all the battery cores in the target power battery can be analyzed by a principal component analysis method or a clustering method, and the internal resistances of all the battery cores can also be analyzed to screen abnormal battery cores with larger data difference of other battery cores.
4. The abnormal cell 30 is determined based on the charging and discharging current 34 under the normal operating condition of the power battery.
In the embodiment, a first load current value of all the power batteries in the power battery cluster in operation and a second load current value of charging under normal working conditions are obtained.
And determining a target power battery from the power battery cluster, wherein the times that the first load current value of the target power battery is greater than the third preset current value are greater than a fourth target time, and/or the times that the second load current value of the target power battery is less than the fourth preset current value are greater than a fifth target time.
When the power battery runs under a normal working condition, the running voltage and current of the battery are within a certain range, and the voltage or current exceeding range is the performance of abnormal work of the power battery, which indicates that an abnormal battery core may exist in the power battery at the moment.
And the frequency that the first load current value exceeds the third preset current during running or the frequency that the second load current value exceeds the fourth preset current during charging is taken as a judgment standard for the possibility of abnormal electric cores in the power battery.
The first load current value is discharge data under a normal working condition, the second load current value is charge data under the normal working condition, and only one of the discharge data or the charge data can be used when judging the abnormal electric core.
The first load current value and the second load current value are the embodiment of the load capacity of the power battery, and if the first load current value and the second load current value are overlarge frequently, the situation that the power battery is in high-load operation frequently is shown, the battery condition is possibly poor, and an abnormal battery core may exist in the battery.
In specific implementation, the third preset current and the fourth preset current may be set according to performance and use conditions of the power battery, for example, the third preset current is set to-180A, and the fourth preset current is set to 180A.
When the number of times that the first load current value is greater than the third preset current is greater than the fourth target number of times, or the number of times that the second load current value is greater than the fourth preset current is greater than the fifth target number of times, it may be determined that an abnormal cell exists in the power battery, where the power battery is a target power battery in the power battery cluster.
In specific implementation, the fourth target frequency and the fifth target frequency can be set according to the use condition of the power battery, and the fourth target frequency and the fifth target frequency can be the same or different.
For example, the fourth target number and the fifth target number may be the same, and both are 10.
In the following, a specific embodiment is described, and the first load current value and the second load current value under the normal condition of one power battery in the power battery cluster are obtained by the BMS, as shown in table 4.
In the discharge data of the first load current value shown in table 4, the times that the absolute value of the first load current is greater than the third preset current value 180A are 16 times in total, and are greater than the fourth target time by 10 times, the power battery is often in high-load operation, and an abnormal battery core exists in the power battery.
In the heavy electricity data of the second load current value, the times that the second load current absolute value is greater than the fourth preset current value 180A are 51 times in total and 10 times greater than the fifth target time, the power battery is usually in high-load operation, and an abnormal battery core exists in the power battery.
TABLE 4
The current is negative during discharging, positive during charging, and the magnitude of the current is compared with the absolute value of the current value.
Under normal working conditions, the charging and discharging current of the power battery is too high, the power battery is usually in high-load operation, the power battery is a target power battery in a power battery cluster, and abnormal battery cores need to be screened.
After the target power battery is determined, the charging data, the discharging data or the temperature data of all the battery cores in the target power battery can be analyzed by a principal component analysis method or a clustering method, and the internal resistances of all the battery cores can also be analyzed to screen abnormal battery cores with larger data difference of other battery cores.
5. The abnormal cell 30 is determined based on the temperature data 35 of the power battery.
In the embodiment, the battery temperature of all the power batteries in the power battery cluster is obtained; and determining a target power battery from the power battery cluster, wherein the times that the battery temperature of the target power battery is higher than the target temperature are higher than the sixth target times.
When the power battery works normally, the battery temperature has a certain range, and the power battery is in an abnormal working state when the battery temperature exceeds the range.
The power battery generally operates in a room temperature environment, the battery temperature of the power battery is not much different from the room temperature, if the battery temperature of the power battery exceeds the room temperature too much, the power battery is overheated, and the service life of the power battery is greatly shortened.
And acquiring temperature data of the power batteries in the power battery cluster through the BMS, wherein the temperature data comprises the battery temperature of the power batteries and the ambient temperature.
In specific implementation, the preset low voltage of the threshold target temperature of the battery temperature can be set according to the performance of the power battery and the use environment, for example, the target temperature is set to 40 degrees celsius in a room temperature environment.
When the number of times that the battery temperature is higher than the target temperature is larger than the sixth target number of times, the battery temperature of the power battery is often greatly different from the ambient temperature, which indicates that the thermal management effect of the battery is poor, and an abnormal battery core exists in the power battery, and the power battery is the target power battery in the power battery cluster.
After the target power battery is determined, the charging data, the discharging data or the temperature data of all the battery cores in the target power battery can be analyzed by a principal component analysis method or a clustering method, and the internal resistances of all the battery cores can also be analyzed to screen abnormal battery cores with larger data difference of other battery cores.
6. The abnormal cell 30 is determined based on the charge stabilization voltage 36 of the power battery.
In this embodiment, under the condition that the target power battery is fully charged, the charging stabilization voltages of all the battery cores in the target power battery are obtained; and determining an abnormal cell from all the cells based on the charging stabilization voltage.
The target power battery can be the target power battery screened in the cases of one to five, and can also be the target power battery which is directly selected by a user and needs to be analyzed.
During specific implementation, after the target power battery is fully charged, the cell codes and cell performance data with the highest cell voltages of the preset number in the target power battery are counted, and abnormal cells are judged based on the frequency of the same cell.
The charging stable voltage is sorted according to the size of the battery cell, the battery cell code of a certain battery cell is often found in the highest ranking of the battery cell voltage, and the battery cell can be screened to be an abnormal battery cell.
In the following, a specific example is described, and the charging stabilization voltage data of the target power battery is obtained by the BMS, as shown in table 5:
TABLE 5
| The highest first 5 cell voltages | Battery core code | Voltage of | Unit of |
| High cell voltage 1 st | 65 | 4147 | mV |
| High cell voltage 2 nd name | 68 | 4146 | mV |
| High cell voltage 3 rd | 67 | 4145 | mV |
| High cell voltage 4 th | 2 | 4145 | mV |
| The cell voltage is higher than 5 th | 5 | 4145 | mV |
In the charging data of the charging stabilization voltage shown in table 5, the cell code and the voltage value of the cell with the highest voltage after each charging are determined, and if the frequency of the five cell codes appearing in the front is greater than the preset frequency, it is indicated that the cell is an abnormal cell.
For example, the preset frequency is 50%, and in 10 times of full charge data, a certain cell code appears 6 times in the first five cells, which indicates that the cell is an abnormal cell.
In actual execution, the highest cell voltage of P of the charging stable voltages of all the cells is obtained, and if the charging stable voltage of a certain cell is always located at the front P position, the cell is an abnormal cell;
wherein N is more than P and is more than or equal to 1,N is the number of all the battery cells.
For example, in the charging data of the charging stabilization voltage shown in table 5, the cell code and the voltage value of the cell with the highest voltage after each charging are determined, and if a certain cell code is always located at the first 5 bits, it is indicated that the cell is an abnormal cell.
7. The abnormal cell 30 is determined based on the discharge stabilization voltage 37 of the power battery.
In the embodiment, after the target power battery runs for a preset time, the discharge stable voltages of all the battery cores in the target power battery are obtained; and determining an abnormal cell from all the cells based on the discharge stabilization voltage.
The target power battery can be the target power battery screened in the former five cases, and can also be the target power battery selected by the user for analysis.
In specific implementation, after the target power battery runs for a preset time, counting the cell codes and cell performance data with the lowest cell voltages in the target power battery, and judging abnormal cells based on the frequency of the same cell.
After the target power battery runs for the preset time, the discharge stable voltage of all the battery cells is obtained, and the situation that the abnormal battery cells cannot be accurately screened due to the fact that the voltage difference of the battery cells in the short-time running of the power battery is not large is avoided.
The discharge stable voltages are sequenced according to the sizes of the battery cells, the battery cell codes of a certain battery cell often appear in the ranking with the lowest battery cell voltage of the discharge stable voltages, and the battery cell can be screened as an abnormal battery cell.
And after each operation, judging the cell code and the voltage value with the lowest cell voltage, and if the frequency of the last five cell codes is greater than the preset frequency, indicating that the cell is an abnormal cell.
For example, the preset frequency is 50%, and after 10 times of operation within the preset time, a certain cell code appears 6 times in the last five cells, which indicates that the cell is an abnormal cell.
In actual execution, the lowest cell voltages of the discharge stable voltages of all the cells are Q, and if the charge stable voltage of a certain cell is always in the rear Q position, the cell is an abnormal cell;
wherein N is more than Q and is more than or equal to 1,N is the number of all the battery cells.
For example, in the discharge data of the discharge stabilization voltages of all the battery cells, the battery cell code and the voltage value of the lowest battery cell voltage before each discharge are determined, and if a certain battery cell code is always located in the last 5 digits, it is indicated that the battery cell is an abnormal battery cell.
It should be noted that the voltage reading is required to be performed after a period of silence after charging or running, and the read voltage value is a stable voltage value including a charging stable voltage and a discharging stable voltage.
As shown in fig. 4, when the abnormal battery cell 420 is determined according to the conditions from one to seven, if any one of the conditions from one to seven satisfies 421, the target power battery that is abnormally operated is present, the target power battery is screened, the abnormal battery cell of the target power battery is determined, and the internal resistance 422 of the abnormal battery cell is determined.
The charge capacity information 410 of the target power battery satisfying the standing condition 411 is acquired, and the charge capacity value 412 of the target power battery is calculated.
And combining the charging capacity value 412 of the target power battery and the internal resistance 422 of the abnormal battery cell to obtain the battery health state 430 of the target power battery.
It can be understood that, based on one of the charging data, the discharging data and the temperature data of the power battery cluster, an abnormal cell may be determined from the power battery cluster.
The following describes a monitoring device for a power battery provided by the present invention, and the monitoring device for a power battery described below and the monitoring method for a power battery described above may be referred to correspondingly.
As shown in fig. 5, the present invention provides a monitoring device for a power battery, comprising:
an obtaining module 510, configured to obtain capacity data and at least one of charging data, discharging data, and temperature data of a power battery cluster;
the determining module 520 is configured to determine an abnormal electrical core from the power battery cluster based on at least one of charging data, discharging data, and temperature data of the power battery cluster;
a first calculating module 530, configured to determine an internal resistance of an abnormal cell;
the second calculating module 540 is configured to determine a charge capacity value of the target power battery based on capacity data of the target power battery where the abnormal electrical core is located;
and a third calculating module 550 for determining the battery health status of the target power battery based on the internal resistance and the charge capacity value.
According to the monitoring device of the power battery, provided by the invention, abnormal cells are screened out through analysis of historical data of the power battery, the health state of the battery is determined based on the internal resistance and the charging capacity value, the influence of capacity errors and temperature on the health state of the battery is reduced, the accuracy of the health state of the battery is improved, and the service life of the power battery is more accurately evaluated.
In some embodiments, the first calculating module 530 is configured to determine the internal resistance of the abnormal cell, and includes: acquiring a voltage difference and a balance current of the abnormal electric core in the class balance circuit based on the main average balance module; determining an internal resistance based on the voltage difference and the balancing current; and the resistance of the quasi-equalization circuit is greater than that of the equalization circuit of the power battery cluster.
In some embodiments, the second calculating module 540 is configured to determine, based on the capacity data of the target power battery where the abnormal electrical core is located, a charge capacity value of the target power battery;
the method comprises the following steps: acquiring the pre-charging charge quantity and the post-charging charge quantity of a target power battery; and determining the charging capacity value of the target power battery based on the pre-charging electric quantity, the post-charging electric quantity and the charging electric quantity.
In some embodiments, the second calculation module 540 is further configured to apply a formula
Cap＝AmpHrs/(SOC2-SOC1)
And determining a charging capacity value, wherein Cap is the charging capacity value, ampHrs is the charging capacity, SOC2 is the charged capacity after charging, and SOC1 is the charged capacity before charging.
In some embodiments, the third calculation module 450 is also used to apply formulas
HVBatSOH＝kCAP*(Cap/CAPBOL)-kRd*(DCRL/DCRL0)+koffset
Determining a battery state of health; the HVBatSOH is the state of health of the battery, the kCAP is a capacity correction parameter of the target power battery, kRd is an internal resistance correction parameter of the target power battery, the koffset is a service life correction parameter of the target power battery, CAPBOL is an initial capacity value of the target power battery, cap is a charging capacity value, DCRL is an internal resistance, and DCRL0 is an initial internal resistance of an abnormal battery cell.
In some embodiments, the determining module 520 is configured to determine the abnormal cell from the power battery cluster based on at least one of charging data, discharging data and temperature data of the power battery cluster, and includes:
determining a target power battery from the power battery cluster; determining internal resistances of all battery cores in a target power battery; and determining an abnormal cell from the cells of the target power battery based on the internal resistances of all the cells in the target power battery.
In some embodiments, the determining module 520 is configured to determine an abnormal cell from a power battery cluster, and includes:
acquiring the balance time of all power batteries in the power battery cluster;
and determining a target power battery from the power battery cluster, wherein the number of times that the balance time length of the target power battery is greater than the target time length is greater than the first target number.
In some embodiments, the determining module 520 is configured to determine an abnormal cell from a power battery cluster, and further includes:
acquiring a low-voltage current value of operation of all power batteries in the power battery cluster under the condition that the voltage of all power batteries is lower than a preset low voltage;
and determining a target power battery from the power battery cluster, wherein the times that the low-voltage current value of the target power battery is greater than the first preset current value are greater than the second target times.
In some embodiments, the determining module 520 is configured to determine an abnormal cell from a power battery cluster, and further includes:
acquiring a high-voltage current value of charging of all power batteries in the power battery cluster under the condition that the voltage of all power batteries is higher than a preset high voltage;
and determining a target power battery from the power battery cluster, wherein the times that the high-voltage current value of the target power battery is greater than the second preset current value are greater than a third target time.
In some embodiments, the determining module 520 is configured to determine an abnormal cell from a power battery cluster, and further includes:
acquiring a first load current value of all power batteries in a power battery cluster and a second load current value of charging under a normal working condition;
and determining a target power battery from the power battery cluster, wherein the times that the first load current value of the target power battery is greater than the third preset current value are greater than a fourth target time, and/or the times that the second load current value of the target power battery is less than the fourth preset current value are greater than a fifth target time.
In some embodiments, the determining module 520 is configured to determine an abnormal cell from a power battery cluster, and further includes:
acquiring battery temperatures of all power batteries in a power battery cluster;
and determining a target power battery from the power battery cluster, wherein the times that the battery temperature of the target power battery is greater than the target temperature are greater than a sixth target time.
In some embodiments, the determining module 520 is configured to determine the abnormal cell from the power battery cluster based on at least one of the charging data, the discharging data and the temperature data of the power battery cluster, and further includes:
under the condition that the target power battery is fully charged, acquiring the charging stable voltage of all battery cores in the target power battery; determining an abnormal cell from all cells based on the charging stabilization voltage;
or,
after the target power battery runs for a preset time, acquiring the discharge stable voltage of all the battery cores in the target power battery; and determining an abnormal cell from all the cells based on the discharge stabilization voltage.
Fig. 6 illustrates a physical structure diagram of an electronic device, which may include, as shown in fig. 6: a processor (processor) 610, a communication Interface (Communications Interface) 620, a memory (memory) 630 and a communication bus 640, wherein the processor 610, the communication Interface 620 and the memory 630 communicate with each other via the communication bus 640. The processor 610 may invoke logic instructions in the memory 630 to perform a method of monitoring a power battery, the method comprising: acquiring at least one of charging data, discharging data and temperature data of the power battery cluster and capacity data; determining an abnormal electric core from the power battery cluster based on at least one of charging data, discharging data and temperature data of the power battery cluster; determining the internal resistance of the abnormal cell; determining a charging capacity value of a target power battery based on capacity data of the target power battery where the abnormal battery cell is located; and determining the battery health state of the target power battery based on the internal resistance and the charging capacity value.
In addition, the logic instructions in the memory 630 may be implemented in the form of software functional units and stored in a computer readable storage medium when the logic instructions are sold or used as independent products. Based on such understanding, the technical solution of the present invention or a part thereof which substantially contributes to the prior art may be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and various media capable of storing program codes.
In another aspect, the present invention also provides a computer program product comprising a computer program stored on a non-transitory computer-readable storage medium, the computer program comprising program instructions which, when executed by a computer, enable the computer to perform the method for monitoring a power battery provided by the above methods, the method comprising: acquiring at least one of charging data, discharging data and temperature data of the power battery cluster and capacity data; determining an abnormal electric core from the power battery cluster based on at least one of charging data, discharging data and temperature data of the power battery cluster; determining the internal resistance of the abnormal cell; determining a charging capacity value of a target power battery based on capacity data of the target power battery where the abnormal battery core is located; and determining the battery health state of the target power battery based on the internal resistance and the charging capacity value.
In yet another aspect, the present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored, the computer program being implemented by a processor to perform the monitoring method of the power battery provided in the above aspects, the method including: acquiring at least one of charging data, discharging data and temperature data of the power battery cluster and capacity data; determining an abnormal electric core from the power battery cluster based on at least one of charging data, discharging data and temperature data of the power battery cluster; determining the internal resistance of the abnormal cell; determining a charging capacity value of a target power battery based on capacity data of the target power battery where the abnormal battery core is located; and determining the battery health state of the target power battery based on the internal resistance and the charging capacity value.
The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one position, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding, the above technical solutions may be embodied in the form of a software product, which may be stored in a computer-readable storage medium, such as ROM/RAM, a magnetic disk, an optical disk, etc., and includes several instructions for enabling a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the method according to the embodiments or some parts of the embodiments.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A monitoring method of a power battery is characterized by comprising the following steps:
acquiring at least one of the balance duration, charging data, discharging data and temperature data of the power battery cluster and capacity data;
determining an abnormal electric core from the power battery cluster based on at least one of charging data, discharging data and temperature data of the power battery cluster;
determining the internal resistance of the abnormal electric core;
determining a charging capacity value of a target power battery based on the capacity data of the target power battery where the abnormal battery core is located;
determining a battery state of health of the target power battery based on the internal resistance and the charge capacity value;
using formulas
HVBatSOH=kCAP*(Cap/CAPBOL)-kRd*(DCRL/DCRL0)+koffset
Determining the battery state of health;
wherein, HVBatSOH is the state of health of the battery, kCAP is a capacity correction parameter of the target power battery, kRd is an internal resistance correction parameter of the target power battery, koffset is a life correction parameter of the target power battery, CAPBOL is an initial capacity value of the target power battery, cap is the charging capacity value, DCRL is the internal resistance, and DCRL0 is the initial internal resistance of the abnormal electrical core;
using formulas
Cap=AmpHrs/(SOC2-SOC1)
Determining the charge capacity value;
wherein Cap is the charging capacity value, ampHrs is the charging capacity, SOC2 is the charged capacity of the target power battery after charging, and SOC1 is the charged capacity of the target power battery before charging.
2. The method for monitoring the power battery according to claim 1, wherein the determining the internal resistance of the abnormal cell comprises:
controlling the current magnitude to be target current through a class balancing circuit, and determining the direct current internal resistance of the abnormal electric core based on the target current;
wherein the class equalization circuit comprises: and the DC/DC module is electrically connected with each battery cell end to end and is connected with pulse current.
3. The method for monitoring the power battery according to claim 1, wherein the determining the charge capacity value of the target power battery based on the capacity data of the target power battery in which the abnormal battery cell is located includes:
acquiring the pre-charging electric quantity and the post-charging electric quantity of the target power battery;
and determining the charging capacity value of the target power battery based on the pre-charging electric charge quantity, the post-charging electric charge quantity and the charging electric charge quantity.
4. The method for monitoring the power battery according to any one of claims 1 to 3, wherein determining an abnormal cell from the power battery cluster based on at least one of an equalization time length, charging data, discharging data and temperature data of the power battery cluster comprises:
determining the target power battery from the power battery cluster, wherein the target power battery is provided with the abnormal battery core.
5. The method for monitoring the power battery according to claim 4, wherein the step of determining the target power battery from the power battery cluster comprises the following steps:
acquiring the balance time of all power batteries in the power battery cluster;
determining the target power battery from the power battery cluster, wherein the number of times that the balance time length of the target power battery is greater than the target time length is greater than a first target number of times;
or,
acquiring a low-voltage current value of the operation of all power batteries in the power battery cluster under the condition that the voltage of all power batteries is lower than a preset low voltage;
determining the target power battery from the power battery cluster, wherein the times that the low-voltage current value of the target power battery is larger than a first preset current value are larger than a second target times;
or,
acquiring a high-voltage current value of charging of all power batteries in the power battery cluster under the condition that the voltage of all power batteries is higher than a preset high voltage;
determining the target power battery from the power battery cluster, wherein the number of times that the high-voltage current value of the target power battery is greater than a second preset current value is greater than a third target number of times;
or,
acquiring a first load current value of charging and a second load current value of discharging of all power batteries in the power battery cluster under a high-load working condition;
determining the target power battery from the power battery cluster, wherein the times that the first load current value of the target power battery is larger than a third preset current value are larger than a fourth target times, and/or the times that the second load current value of the target power battery is smaller than a fourth preset current value are larger than a fifth target times;
or,
acquiring the battery temperature of all power batteries in the power battery cluster;
and determining the target power battery from the power battery cluster, wherein the times that the battery temperature of the target power battery is higher than the target temperature are higher than a sixth target time.
6. The method for monitoring the power battery according to any one of claims 1 to 3, wherein an abnormal cell is determined from the power battery cluster based on at least one of charging data, discharging data and temperature data of the power battery cluster, and further comprising:
under the condition that the target power battery is fully charged, standing for a first preset time to obtain the charging stable voltage of all battery cells in the target power battery;
determining the abnormal cell from all the cells based on the charging stabilization voltage;
or,
after the target power battery runs for a preset time and is kept stand for a second preset time, obtaining the discharge stable voltage of all the battery cores in the target power battery;
determining the abnormal cell from the all cells based on the discharge stabilization voltage.
7. The method for monitoring a power cell of claim 6, further comprising:
the P cells with the highest cell voltage in the charging stable voltages of all the cells are determined, and if the charging stable voltage of a certain cell is always located at the front P position, the cell is the abnormal cell;
wherein N is more than P and is more than or equal to 1,N is the number of all the battery cells;
or,
the lowest cell voltage of the discharge stable voltages of all the cells is Q, and if the charge stable voltage of a certain cell is always in the rear Q position, the cell is the abnormal cell;
wherein N is more than or equal to Q and is not less than 1,N is the number of all the battery cells.
8. A monitoring device for a power cell, comprising:
the acquisition module is used for acquiring at least one of the balance duration, the charging data, the discharging data and the temperature data of the power battery cluster and capacity data;
the determining module is used for determining an abnormal electric core from the power battery cluster based on at least one of the balance duration, the charging data, the discharging data and the temperature data of the power battery cluster;
the first calculation module is used for determining the internal resistance of the abnormal battery cell;
the second calculation module is used for determining a charging capacity value of a target power battery based on the capacity data of the target power battery where the abnormal battery cell is located;
the third calculation module is used for determining the battery health state of the target power battery based on the internal resistance and the charging capacity value;
the monitoring device of the power battery is used for realizing the monitoring method of the power battery according to any one of claims 1 to 7;
the third calculation module is used for applying a formula
HVBatSOH=kCAP*(Cap/CAPBOL)-kRd*(DCRL/DCRL0)+koffset
Determining the battery state of health;
wherein, HVBatSOH is the state of health of the battery, kCAP is a capacity correction parameter of the target power battery, kRd is an internal resistance correction parameter of the target power battery, koffset is a life correction parameter of the target power battery, CAPBOL is an initial capacity value of the target power battery, cap is the charging capacity value, DCRL is the internal resistance, and DCRL0 is the initial internal resistance of the abnormal electrical core;
using formulae
Cap=AmpHrs/(SOC2-SOC1)
Determining the charge capacity value;
wherein Cap is the charging capacity value, ampHrs is the charging capacity, SOC2 is the charged capacity of the target power battery after charging, and SOC1 is the charged capacity of the target power battery before charging.
9. An electronic device comprising a memory, a processor and a computer program stored on said memory and executable on said processor, characterized in that said processor implements the steps of the method for monitoring a power cell according to any one of claims 1 to 7 when executing said program.
10. A non-transitory computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method for monitoring a power cell according to any one of claims 1 to 7.
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| CN114384348A (en) * | 2021-10-20 | 2022-04-22 | 国网宁夏电力有限公司检修公司 | Method, medium and system for monitoring health margin of converter valve key assembly |
| CN113985288A (en) * | 2021-10-26 | 2022-01-28 | 广州小鹏汽车科技有限公司 | Method and device for reminding abnormality of component of vehicle battery, vehicle and storage medium |
| CN114035085A (en) * | 2021-12-15 | 2022-02-11 | 湖北德普电气股份有限公司 | Detection method for intelligent direct-current charging pile power battery of electric vehicle |
| CN114839541B (en) * | 2022-05-18 | 2024-08-02 | 山东大学 | Power battery pack inconsistency diagnosis method and system based on K-means clustering |
| CN114879053B (en) * | 2022-06-16 | 2023-05-23 | 珠海科创储能科技有限公司 | Method for predicting service life of energy storage lithium iron phosphate battery |
| CN117220389B (en) * | 2023-11-09 | 2024-04-02 | 宁德时代新能源科技股份有限公司 | Charging method, device, computer equipment and storage medium |
| CN118322941B (en) * | 2024-06-11 | 2024-08-09 | 长城汽车股份有限公司 | Equalizing method and equalizing device for vehicle battery pack, vehicle and storage medium |
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