CN116804715A - Method for judging reasons for inconsistent occurrence of battery system - Google Patents
Method for judging reasons for inconsistent occurrence of battery system Download PDFInfo
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- CN116804715A CN116804715A CN202210269300.4A CN202210269300A CN116804715A CN 116804715 A CN116804715 A CN 116804715A CN 202210269300 A CN202210269300 A CN 202210269300A CN 116804715 A CN116804715 A CN 116804715A
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- 238000000034 method Methods 0.000 title claims abstract description 37
- 238000001914 filtration Methods 0.000 claims abstract description 20
- 238000004364 calculation method Methods 0.000 claims abstract description 11
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 7
- 229910052744 lithium Inorganic materials 0.000 claims description 7
- 238000003860 storage Methods 0.000 claims description 6
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical group [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims description 5
- 229910001416 lithium ion Inorganic materials 0.000 claims description 5
- 238000004146 energy storage Methods 0.000 claims description 4
- 238000001556 precipitation Methods 0.000 claims description 4
- 230000032683 aging Effects 0.000 claims description 3
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 claims description 2
- 238000009499 grossing Methods 0.000 claims description 2
- 238000009533 lab test Methods 0.000 claims description 2
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 claims description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- 229910052799 carbon Inorganic materials 0.000 description 5
- 238000006386 neutralization reaction Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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Abstract
The invention discloses a method for judging inconsistent reasons of battery systems, which comprises the steps of obtaining charging history data of a plurality of battery systems; acquiring and recording the voltage range and time of a battery system for storing the end time of each charge; filtering the obtained voltage range according to the time sequence to obtain a change curve of the voltage range along with time; carrying out differential calculation on the voltage pole difference curve to obtain a slope K; drawing a change curve of the slope and time for the slope K obtained in the step four; comparing the battery system with faults with the battery system without faults to obtain a judging threshold value of the slope K; and according to the judgment threshold value, giving a cause for the inconsistency of the battery system. The invention can locate the cause of the inconsistency of the battery system, and uses the voltage range at the time of the end of charging to conduct differential calculation to obtain the slope, and further conduct the judgment of the threshold value, thereby judging the specific cause of the inconsistency of the battery system.
Description
Technical Field
The invention belongs to the technical field of battery systems, and particularly relates to a method for judging reasons for inconsistent occurrence of a battery system.
Background
In recent decades, new energy automobiles are developed into a fast-driving lane, and the conservation amount of electric automobiles is higher and higher. The sales of electric automobiles in China are kept the first world for many years. The last year of China clearly puts forward at the congress of China, and the carbon dioxide emission strives to reach a peak before 2030 and strives to achieve carbon neutralization before 2060. The targets of carbon peak and carbon neutralization are firstly changed into the energy industry pattern, the specific gravity of renewable energy sources is improved, the use of fossil energy sources is reduced, and the necessary requirements of carbon peak and carbon neutralization are realized. For the automotive industry, the development of electric vehicles will face significant development opportunities, as well as significant challenges and risks.
The number of new energy automobiles is continuously increasing, but with this, the safety problem of electric automobiles is also increasingly prominent. In the use process of the electric automobile, a series of problems such as consistency, thermal runaway, battery attenuation and the like can occur, and the personal and property safety of a user is threatened. In a battery system on an electric automobile, a plurality of electric cells are included, and the difference between the production process and the use environment of each electric cell can cause inconsistent problems among all single electric cells, including voltage, internal resistance, capacity and the like. At present, many scholars and research institutions do a lot of research on the problem of non-uniformity of a battery system, and mainly focus on the following aspects: 1) Evaluating the consistency state of single battery cells in a battery system, wherein the evaluation indexes comprise voltage consistency, temperature consistency, internal resistance consistency, capacity consistency and the like; 2) Cell sorting is carried out by utilizing inconsistency among the cells, and cell sorting is carried out according to voltage or capacity; 3) And analyzing the influence of the inconsistency among the battery cells on the performance of the battery system. The above-described study on the consistency of the battery does not involve analysis of the cause of the problem of the inconsistency of the battery system, and does not determine the source of the problem of the inconsistency, but only evaluates and uses the current status of the consistency of the battery system. The method can judge the cause of the inconsistency problem, and can know and judge the safety of the battery system in the future use process.
In summary, it is necessary to determine the cause of the inconsistency of the battery system, and to guide the safe use of the battery system.
Disclosure of Invention
In order to overcome the above problems, the present invention provides a method of judging the cause of the inconsistency of the battery system.
The technical scheme adopted by the invention is as follows:
a method of determining a cause of an inconsistency in a battery system, comprising the steps of:
step one: acquiring charging history data of a plurality of battery systems;
step two: acquiring and recording the voltage range and time of a battery system for storing the end time of each charge;
step three: filtering the voltage range obtained in the second step according to the time sequence to obtain a change curve of the voltage range along with time;
step four: carrying out differential calculation on the voltage pole difference curve in the third step to obtain a slope K;
step five: drawing a change curve of the slope and time for the slope K obtained in the step four;
step six: comparing the battery system with faults with the battery system without faults to obtain a judging threshold value of the slope K;
step seven: and according to the judgment threshold value, giving a cause for the inconsistency of the battery system.
The lithium ion battery comprises a lithium iron phosphate battery, a ternary battery, a lithium manganate battery and a lithium cobaltate battery; the battery management system comprises a vehicle-mounted BMS and a cloud BMS, and the electric vehicle and the energy storage device which use the lithium ion battery comprise an electric bicycle, an electric automobile, a UPS, an energy storage battery cluster and a container.
The method comprises the steps that in the first step, a carrier for acquiring charging history data is a storage medium, and the storage medium comprises laboratory test equipment, a storage medium on equipment with a battery and a cloud platform for receiving and storing equipment operation data.
Wherein the battery system comprises a battery system with a failure tag comprising an internal short circuit or lithium evolution.
Wherein, the formula of the voltage range is as follows:
ΔV(i)＝V max (i)-V min (i),i＝1,2...n
where Δv (i) is the voltage range, the unit V (volt), vmax (i) is the single highest voltage at the i-th charge end time, vmin (i) is the single lowest voltage at the i-th charge end time, and i is the number of charges.
The filtering mode in the third step comprises a limiting filtering method, a median filtering method, an arithmetic average filtering method, a smoothing filtering method, a wiener filtering method and a Gaussian filtering method, and aims to eliminate abnormal points and fluctuation points.
The formula for obtaining the slope K by differential calculation in the fourth step is as follows:
wherein T (i) is the time corresponding to the charging end time of the ith time, i is the number of times of charging, j is the number of intervals of the number of times of charging, and the value range of the number of times of charging is 1.ltoreq.j.ltoreq.i-1.
The judgment threshold value obtained in the step six is A, and the cause of the inconsistency of the battery system is judged and positioned, 1) K is more than or equal to A in a K-T curve, and the cause of the inconsistency of the battery system is considered to be internal short circuit or lithium precipitation; 2) K < A, it is considered that the cause of the inconsistency of the battery system is the inconsistency of the internal resistances caused by the normal aging of the individual battery cells in the battery system.
Further, the voltage may be replaced with a capacity or energy or other physical quantity that is used to measure the state of the battery. Wherein the battery capacity refers to the electric quantity stored in the battery, and the unit is ampere hour (Ah); battery energy refers to stored energy in watt-hours (Wh).
Further, the time (T) may be replaced with the total mileage of the vehicle.
The innovation points and advantages of the invention are as follows:
the invention can locate the cause of the inconsistency of the battery system, and uses the extremely poor voltage (or other physical quantity such as capacity/energy which can measure the battery state) at the time of the end of charging to perform differential calculation to obtain the slope, and further to perform judgment of the threshold value, thereby judging the specific cause of the inconsistency of the battery system, and has very important practical value.
Drawings
FIG. 1 is a flow chart of a method of determining the cause of a battery system inconsistency according to the present invention;
FIG. 2 is a schematic diagram of V-T and K-T curves of a battery system with internal short circuit failure in an embodiment of a method of determining a cause of an inconsistency in the battery system according to the present invention;
FIG. 3 is a schematic view of V-T and K-T curves of a battery system that has not failed in an embodiment of a method of determining a cause of a non-uniformity in the battery system according to the present invention.
Detailed Description
The present invention will be further illustrated by the following specific examples, which are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the following examples. Some insubstantial modifications and variations of the invention as described above would be within the purview of one skilled in the art in light of the disclosure.
In an embodiment, as shown in fig. 1:
s101, firstly, acquiring operation history data of a battery system; the historical data is obtained through a data platform, and the data platform can receive data and information generated by a battery system of the electric automobile in real time; the obtained historical data comprises a battery system with an internal short circuit fault label and a normal battery system without faults;
s102, cleaning the acquired historical data, and calculating and storing the voltage range and time at the time of the charging end;
the calculation formula of the voltage range is as follows:
ΔV(i)＝V max (i)-V min (i),i＝1,2...n
where Δv (i) is the voltage range, vmax (i) is the highest voltage of the cell at the i-th charge end time, vmin (i) is the lowest voltage of the cell at the i-th charge end time, and i is the number of charges;
in the obtained history data, if there are 50 charges, a voltage range sequence (Δv (1), Δv (2) … Δv (50)) and a time sequence (T (1), T (2) … T (50)) can be obtained;
the obtained voltage range sequence is subjected to filtering treatment by Gaussian filtering according to a time sequence to obtain an original delta V-T curve, and a smooth delta V-T curve is obtained;
s103, calculating and storing the slope K of the obtained DeltaV-T curve, wherein the formula is as follows:
wherein T (i) is the time corresponding to the charging ending time of the ith time, i is the charging times, j is the interval number of the charging times, and the value range of the interval number is 1-j-1;
selecting i=50 and j=10, and performing calculation of K every 10 charges according to the following formula:
obtaining a sequence (K (1), K (2) … K (40)) with a slope K, and further obtaining a K-T curve;
s104, comparing and judging the K-T curve of the battery system with faults such as internal short circuit or lithium precipitation with the K-T curve of the battery system without faults according to the curve (K-T) of the K and the time T. As shown in fig. 2 and 3, by comparing fig. 2 and 3, the threshold value a is 1.
S105, judging and positioning the reasons for the inconsistency of the battery system according to the obtained threshold A, wherein in the K-T curve in FIG. 2, K is more than or equal to 1, and the reasons for the inconsistency of the battery system are mainly internal short circuit faults, and the voltage of the battery core is abnormally reduced due to the existence of the internal short circuit of the battery; in fig. 3, K < 1, it is considered that the cause of the inconsistency of the battery system is mainly due to the inconsistency of the internal resistances caused by the normal aging of the individual battery cells in the battery system.
In summary, the method for judging the cause of inconsistency of the battery systems provided by the embodiment of the invention acquires charging history data of a plurality of battery systems; acquiring and recording the extremely poor voltage (or physical quantity such as capacity/energy which can characterize the battery state) and time (or mileage) of the battery system at each charging end time; filtering the obtained extremely poor voltage (or physical quantity which can represent the battery state such as capacity/energy) according to the time (or mileage) sequence to obtain a change curve of the extremely poor voltage (or physical quantity which can represent the battery state such as capacity/energy) along with the time (or mileage); carrying out differential calculation on a voltage (or physical quantity which can represent the battery state such as capacity/energy) extremely poor curve to obtain a slope K; drawing a change curve of the slope and time for the slope K obtained in the step four; comparing the battery system with faults with the battery system without faults to obtain a judging threshold value of the slope K; and according to the judgment threshold value, giving a cause for the inconsistency of the battery system. The invention can locate the cause of the inconsistency of the battery system, and can judge the specific cause of the inconsistency of the battery system by utilizing the extremely poor voltage (or physical quantity which can represent the battery state such as capacity/energy) at the time of finishing charging, carrying out differential calculation to obtain the slope and further judging the threshold value.
The above examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above examples, and any other changes, modifications, substitutions, combinations, and simplifications that do not depart from the spirit and principle of the present invention should be made in the equivalent manner, and the embodiments are included in the protection scope of the present invention.
Claims (10)
1. A method of determining a cause of an inconsistency in a battery system, comprising: the method comprises the following steps:
step one: acquiring charging history data of a plurality of battery systems;
step two: acquiring and recording the voltage range and time of a battery system for storing the end time of each charge;
step three: filtering the voltage range obtained in the second step according to the time sequence to obtain a change curve of the voltage range along with time;
step four: carrying out differential calculation on the voltage pole difference curve in the third step to obtain a slope K;
step five: drawing a change curve of the slope and time for the slope K obtained in the step four;
step six: comparing the battery system with faults with the battery system without faults to obtain a judging threshold value of the slope K;
step seven: and according to the judgment threshold value, giving a cause for the inconsistency of the battery system.
2. The method of claim 1, wherein the step of determining a cause of the inconsistency in the battery system comprises: the battery is a lithium ion battery, and the lithium ion battery comprises a lithium iron phosphate battery, a ternary battery, a lithium manganate battery and a lithium cobaltate battery; the battery management system comprises a vehicle-mounted BMS and a cloud BMS, and the electric vehicle and the energy storage device which use the lithium ion battery comprise an electric bicycle, an electric automobile, a UPS, an energy storage battery cluster and a container.
3. The method of claim 1, wherein the step of determining a cause of the inconsistency in the battery system comprises: the carrier for acquiring the charging history data in the first step is a storage medium, and the storage medium comprises laboratory test equipment, a storage medium on equipment with a battery and a cloud platform for receiving and storing equipment operation data.
4. The method of claim 1, wherein the step of determining a cause of the inconsistency in the battery system comprises: the battery system comprises a battery system with a fault label, wherein the fault label comprises internal short circuit or lithium precipitation.
5. The method of claim 1, wherein the step of determining a cause of the inconsistency in the battery system comprises: the formula of the voltage range in the second step is as follows:
ΔV(i)＝V max (i)-V min (i),i＝1,2...n
where Δv (i) is the voltage range, the unit V (volt), vmax (i) is the single highest voltage at the i-th charge end time, vmin (i) is the single lowest voltage at the i-th charge end time, and i is the number of charges.
6. The method of claim 1, wherein the step of determining a cause of the inconsistency in the battery system comprises: the filtering mode in the third step comprises a limiting filtering method, a median filtering method, an arithmetic average filtering method, a smoothing filtering method, a wiener filtering method and a Gaussian filtering method.
7. The method of claim 1, wherein the step of determining a cause of the inconsistency in the battery system comprises: in the fourth step, the formula for obtaining the slope K by differential calculation is as follows:
wherein T (i) is the time corresponding to the charging end time of the ith time, i is the number of times of charging, j is the number of intervals of the number of times of charging, and the value range of the number of times of charging is 1.ltoreq.j.ltoreq.i-1.
8. The method of claim 1, wherein the step of determining a cause of the inconsistency in the battery system comprises: the judgment threshold value obtained in the step six is A, and the cause of the inconsistency of the battery system is judged and positioned, 1) K is more than or equal to A in a K-T curve, and the cause of the inconsistency of the battery system is considered to be internal short circuit or lithium precipitation; 2) K < A, it is considered that the cause of the inconsistency of the battery system is the inconsistency of the internal resistances caused by the normal aging of the individual battery cells in the battery system.
9. The method of claim 5 or 7, characterized in that the voltage is replaced by a capacity or energy or the like for measuring other physical quantities of the battery state.
10. Method according to claim 5 or 7 or 9, characterized in that the time (T) is replaced by the total vehicle mileage.
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| CN117148200A (en) * | 2023-10-26 | 2023-12-01 | 中能建储能科技(武汉)有限公司 | PACK inconsistency monitoring method and device based on piecewise aggregation approximation and clustering |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117148200A (en) * | 2023-10-26 | 2023-12-01 | 中能建储能科技(武汉)有限公司 | PACK inconsistency monitoring method and device based on piecewise aggregation approximation and clustering |
| CN117148200B (en) * | 2023-10-26 | 2024-03-15 | 中能建储能科技(武汉)有限公司 | PACK inconsistency monitoring method and device based on piecewise aggregation approximation and clustering |
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