CN-114441978-B - Fault diagnosis method and device for battery cluster, terminal equipment and storage medium

CN114441978BCN 114441978 BCN114441978 BCN 114441978BCN-114441978-B

Abstract

The invention discloses a fault diagnosis method of a battery cluster, which comprises the steps of obtaining target temperature of the target battery cluster, determining target impedance spectrum curves corresponding to the target temperature in a preset curve library, wherein the preset curve library comprises impedance spectrum curves corresponding to different temperatures, each impedance spectrum curve is obtained according to alternating current excitation currents with different frequencies, the alternating current excitation currents with different frequencies are obtained from an external power grid, and obtaining fault diagnosis results of the target battery cluster according to the target impedance spectrum curves. The invention also discloses a fault diagnosis device of the battery cluster, terminal equipment and a storage medium. By using the method provided by the invention, the target impedance spectrum curve is excited by using the AC/AC alternating current, so that the disturbance to a direct current system can be reduced, the test reliability is improved, the accuracy of the target impedance spectrum curve is higher, and the accuracy of the obtained fault diagnosis result is higher.

Inventors

DONG PUYUN
QIAN CHAO
HE WEI
SHAO JUNWEI

Assignees

阳光储能技术有限公司

Dates

Publication Date: 20260508
Application Date: 20220127

Claims (13)

1. A fault diagnosis method of a battery cluster, the method comprising the steps of: acquiring a target temperature of a target battery cluster; Determining a target impedance spectrum curve corresponding to the target temperature in a preset curve library, wherein the preset curve library comprises impedance spectrum curves corresponding to different temperatures, each impedance spectrum curve is obtained according to alternating current excitation currents with different frequencies, and the alternating current excitation currents with different frequencies are obtained from an external power grid; obtaining a fault diagnosis result of the target battery cluster according to the target impedance spectrum curve; The target impedance spectrum curves are divided into a first impedance spectrum curve corresponding to a high-frequency impedance area and a second impedance spectrum curve corresponding to a low-frequency impedance area, so that a plurality of first impedance spectrum curves and a plurality of second impedance spectrum curves are obtained, fault diagnosis results comprise a first impedance analysis result of the high-frequency impedance area and a second impedance analysis result of the low-frequency impedance area, the first impedance analysis result is determined at least according to the impedance change trend of the high-frequency impedance area, and the second impedance analysis result is determined at least according to fitting semicircles of the second impedance spectrum curves.
2. The method of claim 1, wherein the target impedance spectrum curve comprises a plurality of target impedance spectrum curves, and wherein the step of obtaining the fault diagnosis result of the target battery cluster based on the target impedance spectrum curves comprises: analyzing the high-frequency impedance region according to a plurality of first impedance spectrum curves to obtain a first impedance analysis result; analyzing the low-frequency impedance region according to a plurality of second impedance spectrum curves to obtain a second impedance analysis result; and obtaining the fault diagnosis result according to the first impedance analysis result and the second impedance analysis result.
3. The method of claim 2, wherein the step of analyzing the high frequency impedance region according to a plurality of the first impedance spectroscopy curves to obtain a first impedance analysis result comprises: Obtaining impedance change trend information corresponding to the high-frequency impedance region according to a plurality of the first impedance spectrum curves; If the impedance change trend information is in an increasing state, determining a first impedance change rate within a first preset time period and a second impedance change rate within a second preset time period according to the impedance change trend information, wherein the first preset time period is longer than the second preset time period; And obtaining the first impedance analysis result according to the first impedance change rate and the second impedance change rate.
4. A method as claimed in claim 3, wherein said step of analyzing said low frequency impedance region based on a plurality of said second impedance spectra to obtain a second impedance analysis result comprises: determining a fitted semicircle of a plurality of the second impedance spectrum curves; When the diameter of the fitting semicircle is in an increasing state, judging whether a diameter rapid increasing region with the increasing multiplying power of the inner diameter being larger than that of the first preset diameter increasing rate in a third preset duration exists in the fitting semicircle; If the diameter rapid increase area exists, determining a target diameter increase rate of the semicircle diameter within a fourth preset time period in the fitted semicircle, wherein the third preset time period is longer than the fourth preset time period; and obtaining the second impedance analysis result according to the target diameter increase rate.
5. The method of claim 4, wherein, When the first impedance change rate is greater than or equal to a first preset impedance change rate and the battery cells of the target battery cluster are aged, the first impedance analysis result comprises aging degree information of the target battery cluster, or, When the first impedance change rate is greater than or equal to a first preset impedance change rate and the target battery cluster does not have battery cell aging, the first impedance analysis result comprises the initial stage of connecting piece failure and/or welding spot fatigue of the target battery cluster, or, When the second impedance change rate is smaller than a second preset impedance change rate, the first impedance analysis result comprises that the impedance of the electrolyte in the target battery cluster is increased, or, When the second impedance change rate is greater than or equal to a third preset impedance change rate, the first impedance analysis result includes an internal short circuit of the battery cell in the target battery cluster, the third preset impedance change rate is greater than the second preset impedance change rate, or, And when the second impedance change rate is smaller than the third preset impedance change rate and is larger than or equal to the second preset impedance change rate, the first impedance analysis result comprises that the aging speed of the battery cells in the target battery cluster is increased or micro short circuit occurs.
6. The method of claim 5, wherein after the step of determining whether there is a rapid increase in diameter region in the fitted semicircle having an increase rate of the inner diameter greater than the first predetermined increase rate of the diameter for a third predetermined period of time, the method further comprises: if the diameter rapid increase area does not exist, judging whether the high-frequency internal resistance of the target battery cluster is increased; if the high-frequency internal resistance of the target battery cluster is increased, obtaining a fault diagnosis result of the target battery cluster or, And if the high-frequency internal resistance of the target battery cluster is not increased, obtaining a fault diagnosis result of the aging of the battery cells of the target battery cluster.
7. The method of claim 6, wherein the step of obtaining the second impedance analysis result according to the target diameter increase rate comprises: and when the target diameter increase rate is smaller than a third preset diameter increase rate, obtaining a second impedance analysis result of normal reaction impedance in the target battery cluster, or, When the target diameter increase rate is greater than or equal to a fourth preset diameter increase rate, obtaining a second impedance analysis result of the slow aging of the battery cells in the target battery cluster, wherein the fourth preset diameter increase rate is greater than the third preset diameter increase rate, or, And when the target diameter increase rate is smaller than the fourth preset diameter increase rate and is larger than or equal to the third preset diameter increase rate, obtaining a second impedance analysis result of the accelerated aging speed of the battery cells in the target battery cluster.
8. The method of claim 1, wherein prior to the step of determining a target impedance spectrum profile corresponding to the target temperature in a library of preset profiles, the method comprises: acquiring the running state information of the target battery cluster in the running process of the target battery cluster; if the running state information meets the preset condition, acquiring the working temperature of the target battery cluster; If the working temperature is matched with a preset temperature interval, determining a preset frequency interval of alternating excitation current corresponding to the working temperature; determining a plurality of preset frequencies in the preset frequency interval according to the operation condition of the target battery cluster in the preset frequency interval at the working temperature; Drawing a preset impedance spectrum curve corresponding to the working temperature according to a plurality of preset alternating current excitation currents corresponding to a plurality of preset frequencies and the working temperature; adding the preset impedance spectrum curve to the preset curve library.
9. The method of claim 8, wherein the step of plotting a predetermined impedance spectrum curve corresponding to the operating temperature from a plurality of predetermined ac excitation currents corresponding to a plurality of predetermined frequencies and the operating temperature comprises: exciting the target battery cluster by using each preset alternating current excitation current at the working temperature to obtain excitation impedance corresponding to each preset alternating current excitation current; And drawing a preset impedance spectrum curve corresponding to the working temperature according to a plurality of excitation impedances corresponding to the preset alternating current excitation currents.
10. The method of claim 8, wherein prior to the step of adding the preset impedance spectrum curve to the preset library of curves, the method further comprises: obtaining a standard temperature corresponding to the target battery cluster; According to the standard temperature, the preset impedance spectrum curve is adjusted to obtain an adjusted preset impedance spectrum curve corresponding to the standard temperature; The step of adding the preset impedance spectrum curve to the preset curve library comprises the following steps: and adding the adjusted preset impedance spectrum curve to the preset curve library.
11. A fault diagnosis apparatus for a battery cluster, the apparatus comprising: the acquisition module is used for acquiring the target temperature of the target battery cluster; the determining module is used for determining a target impedance spectrum curve corresponding to the target temperature in a preset curve library, the preset curve library comprises impedance spectrum curves corresponding to different temperatures, each impedance spectrum curve is obtained according to alternating current excitation currents with different frequencies, and the alternating current excitation currents with different frequencies are obtained from an external power grid; The obtaining module is used for obtaining a fault diagnosis result of the target battery cluster according to the target impedance spectrum curve; The target impedance spectrum curves are divided into a first impedance spectrum curve corresponding to a high-frequency impedance area and a second impedance spectrum curve corresponding to a low-frequency impedance area, so that a plurality of first impedance spectrum curves and a plurality of second impedance spectrum curves are obtained, fault diagnosis results comprise a first impedance analysis result of the high-frequency impedance area and a second impedance analysis result of the low-frequency impedance area, the first impedance analysis result is determined at least according to the impedance change trend of the high-frequency impedance area, and the second impedance analysis result is determined at least according to fitting semicircles of the second impedance spectrum curves.
12. A terminal device, characterized in that it comprises a memory, a processor and a fault diagnosis program stored on the memory and running a battery cluster on the processor, which fault diagnosis program, when executed by the processor, implements the steps of the fault diagnosis method of a battery cluster according to any one of claims 1 to 10.
13. A storage medium, wherein a failure diagnosis program of a battery cluster is stored on the storage medium, which when executed by a processor, implements the steps of the failure diagnosis method of a battery cluster according to any one of claims 1 to 10.

Description

Fault diagnosis method and device for battery cluster, terminal equipment and storage medium Technical Field The present invention relates to the field of battery detection technologies, and in particular, to a method and an apparatus for diagnosing a fault of a battery cluster, a terminal device, and a storage medium. Background The battery cluster is formed by connecting a plurality of battery modules in series and parallel, the batches of the battery cells in the battery cluster are different, the initial capacity and the impedance of each battery cell are slightly different, and the influence of the factors on the impedance of each battery cluster is obvious, so that serious consequences can be caused if the identification and the diagnosis are not carried out. In the related art, an energy storage converter integrates direct current of a battery cluster into alternating current through a battery management system, the battery cluster is charged and discharged, and in the process of charging and discharging the battery cluster, impedance detection is carried out on the battery cluster, so that a fault diagnosis result of the battery cluster is further determined. However, by adopting the existing method, the accuracy of impedance detection of the battery cluster is low, so that the accuracy of fault diagnosis results of the battery cluster is low. Disclosure of Invention The invention mainly aims to provide a fault diagnosis method, device, terminal equipment and storage medium for a battery cluster, and aims to solve the technical problem that the accuracy of impedance detection of the battery cluster is low by adopting the existing method in the prior art, so that the accuracy of a fault diagnosis result of the battery cluster is low. In order to achieve the above object, the present invention provides a fault diagnosis method of a battery cluster, the method comprising the steps of: acquiring a target temperature of a target battery cluster; Determining a target impedance spectrum curve corresponding to the target temperature in a preset curve library, wherein the preset curve library comprises impedance spectrum curves corresponding to different temperatures, each impedance spectrum curve is obtained according to alternating current excitation currents with different frequencies, and the alternating current excitation currents with different frequencies are obtained from an external power grid; And obtaining a fault diagnosis result of the target battery cluster according to the target impedance spectrum curve. Optionally, the target impedance spectrum curve comprises a plurality of target impedance spectrum curves, and the step of obtaining the fault diagnosis result of the target battery cluster according to the target impedance spectrum curves comprises the following steps: Dividing each target impedance spectrum curve into a first impedance spectrum curve corresponding to a high-frequency impedance region and a second impedance spectrum curve corresponding to a low-frequency impedance region so as to obtain a plurality of first impedance spectrum curves and a plurality of second impedance spectrum curves; analyzing the high-frequency impedance region according to a plurality of first impedance spectrum curves to obtain a first impedance analysis result; analyzing the low-frequency impedance region according to a plurality of second impedance spectrum curves to obtain a second impedance analysis result; and obtaining the fault diagnosis result according to the first impedance analysis result and the second impedance analysis result. Optionally, the step of analyzing the high-frequency impedance region according to the plurality of first impedance spectrum curves to obtain a first impedance analysis result includes: Obtaining impedance change trend information corresponding to the high-frequency impedance region according to a plurality of the first impedance spectrum curves; If the impedance change trend information is in an increasing state, determining a first impedance change rate within a first preset time period and a second impedance change rate within a second preset time period according to the impedance change trend information, wherein the first preset time period is longer than the second preset time period; And obtaining the first impedance analysis result according to the first impedance change rate and the second impedance change rate. Optionally, the step of analyzing the low-frequency impedance region according to the plurality of second impedance spectrum curves to obtain a second impedance analysis result includes: determining a fitted semicircle of a plurality of the second impedance spectrum curves; When the diameter of the fitting semicircle is in an increasing state, judging whether a diameter rapid increasing region with the increasing multiplying power of the inner diameter being larger than that of the first preset diameter increasing rate in a third preset duration exist