A battery pack fault diagnosis method, system and storage medium

Abstract

The embodiments of the present invention provide a battery pack fault diagnosis method, system and storage medium, which belong to the technical field of circuit fault diagnosis. The diagnosis method includes: constructing an equivalent circuit model of a single cell; constructing a bonding graph model of the single cell according to the equivalent circuit model; constructing a bonding graph model of a battery pack according to the bonding graph model of the single cell; obtaining the voltage and current of each branch of the battery pack according to the bonding graph model of the single cell and the bonding graph model of the battery pack; parsing redundant relationships according to the voltage and current; constructing a fault feature matrix according to the redundant relationship to locate the faulty single cell. The bonding graph modeling method adopted by the present invention clearly describes each single cell of the battery pack. When performing fault diagnosis, the method can effectively identify and locate faulty single cells in the battery pack, thereby improving the reliability and safety of the battery pack.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit fault diagnosis, and in particular to a battery pack fault diagnosis method, system and storage medium. Background Art

[0002] There are a large number of single cells connected in series and parallel inside the battery pack. The abnormality of a single cell will cause the entire battery pack to malfunction, which poses a great challenge to the fault diagnosis of the battery pack. Traditional battery pack fault diagnosis needs to consider battery aging, battery operating conditions and other issues separately, and most of them cannot perform online fault diagnosis, which reduces the overall reliability of the battery pack. Summary of the invention

[0003] The purpose of the embodiments of the present invention is to provide a battery pack fault diagnosis method, system and storage medium, which solve the problem of online fault diagnosis of the battery pack.

[0004] In order to achieve the above object, an embodiment of the present invention provides a battery pack fault diagnosis method, the diagnosis method comprising:

[0005] Construct an equivalent circuit model of a single battery;

[0006] Constructing a bonding graph model of the single cell according to the equivalent circuit model;

[0007] Constructing a bonding graph model of a battery pack according to the bonding graph model of the single battery;

[0008] Obtaining the voltage and current of each branch of the battery pack according to the bonding graph model of the single battery and the bonding graph model of the battery pack;

[0009] Resolving a redundancy relationship based on the voltage and current;

[0010] A fault feature matrix is ​​constructed according to the redundant relationship to locate the faulty single cell.

[0011] Optionally, the equivalent circuit model includes:

[0012] Potential source;

[0013] a first resistor, one end of which is connected to the positive electrode of the potential source;

[0014] a second resistor, one end of the second resistor being connected to the other end of the first resistor;

[0015] A first capacitor, one end of the first capacitor is connected to one end of the second resistor, and the other end of the first capacitor is connected to the other end of the second resistor.

[0016] Optionally, obtaining the voltage and current of each branch of the battery pack according to the bonding graph model of the single battery and the bonding graph model of the battery pack includes:

[0017] According to formulas (1) to (6), the voltage and current of each branch of the battery pack are obtained.

[0018] , (1)

[0019] , (2)

[0020] , (3)

[0021] , (4)

[0022] , (5)

[0023] , (6)

[0024] in, For the Row, No. The ohmic internal resistance of the first resistor of the column, For the Row, No. The polarization internal resistance of the second resistor of the column, For the Row, No. The polarization capacitance of the first capacitor of the column, , , , , and are the currents on each branch of the bond graph model, , , , , and are the voltages on each branch of the bond graph model, is the differential of the voltage of branch number 5, For the Row, No. The potential source of the column, , , is an integer number, is the total number of parallel-connected single-cell rows, is the total number of series-connected cells.

[0025] Optionally, resolving a redundancy relationship according to the voltage and current includes:

[0026] According to formula (7), the redundant relationship is analyzed:

[0027] , (7)

[0028] in, Branch and The voltage, is the redundant relationship of the node “1” in the first column, is the voltage of branch numbered 6 of each single cell in column 1.

[0029] Optionally, constructing a fault feature matrix according to the redundant relationship to locate the faulty single battery includes:

[0030] According to formula (8), the fault feature matrix is ​​constructed:

[0031] , (8)

[0032] in, is the fault feature matrix, , …, , …, is the fault variable, for Each column has , , and Four parameters.

[0033] Optionally, constructing a fault feature matrix according to the redundant relationship to locate the faulty single battery includes:

[0034] According to formula (9), the fault variable of each single cell is determined:

[0035] , (9)

[0036] in, is the fault variable, For the Redundant Relationship , For the Fault parameters;

[0037] The failed single battery is determined according to the fault variable.

[0038] Optionally, determining the faulty single cell according to the fault variable includes, when the fault variable is 1, determining that the corresponding single cell is the faulty single cell.

[0039] On the other hand, the present invention provides a battery pack fault diagnosis system, the system comprising a processor, and the processor is configured to execute any of the diagnostic methods described above.

[0040] In yet another aspect, the present invention provides a computer-readable storage medium storing instructions, wherein the instructions are used to be read by a machine so as to enable the machine to execute any of the above-described diagnostic methods.

[0041] Through the above technical scheme, the present invention provides a battery pack fault diagnosis method, system and storage medium, which uses equivalent ohmic internal resistance to characterize battery aging, uses equivalent polarization capacitance and polarization resistance to characterize battery operating conditions, and establishes a system bond graph model to analyze redundant relationships to achieve fault diagnosis. Compared with the prior art, the bond graph modeling method used in the present invention clearly describes each single cell of the battery pack. When performing fault diagnosis, this method can effectively identify and locate faulty single cells in the battery pack, thereby improving the reliability and safety of the battery pack.

[0042] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings:

[0044] Figure 1 is a flow chart of a diagnostic method according to one embodiment of the present invention;

[0045] Figure 2 is a circuit diagram of an equivalent circuit model according to one embodiment of the present invention;

[0046] Figure 3 is a bonding graph model of a single cell according to one embodiment of the present invention;

[0047] Figure 4 is a bonding graph model of a battery pack according to an embodiment of the present invention;

[0048] Figure 5 is a flow chart of confirming a faulty single cell according to one embodiment of the present invention.

[0049] Description of Reference Numerals

[0050] , a first resistor; , a second resistor; , a first capacitor; , source of momentum. DETAILED DESCRIPTION

[0051] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0052] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that they can be implemented by ordinary technicians in the field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0053] Figure 1 is a flow chart of a diagnostic method according to one embodiment of the present invention, in which the diagnostic method comprises:

[0054] In step S1, an equivalent circuit model of a single battery is constructed.

[0055] In step S2, a bond graph model of a single cell is constructed according to the equivalent circuit model. According to the structure and energy conversion relationship of the equivalent circuit model, the bond graph model is constructed using the basic elements of the bond graph, such as potential source, resistive element, capacitive element, inductive element, etc. The model can reflect the energy transfer and conversion process between the components within the equivalent circuit model.

[0056] In step S3, a bonding graph model of the battery pack is constructed based on the bonding graph model of the single battery.

[0057] In step S4, the voltage and current of each branch of the battery pack are obtained according to the bonding graph model of the single battery and the bonding graph model of the battery pack.

[0058] In step S5, the redundancy relationship is resolved based on the voltage and current.

[0059] In step S6, a fault feature matrix is ​​constructed according to the redundancy relationship to locate the faulty single battery.

[0060] Compared with the prior art, the present invention establishes a system bond graph model and then analyzes the redundant relationship to achieve online fault diagnosis. The bond graph modeling method adopted by the present invention clearly describes each single cell. When performing fault diagnosis, the method can effectively identify and locate the faulty single cell in the battery pack, thereby improving the reliability and safety of the battery pack. By diagnosing the fault of the single cell, potential safety hazards can be discovered and handled in a timely manner, avoiding the performance degradation or safety accidents of the entire battery pack caused by the faulty single cell.

[0061] In this implementation, the specific composition of the equivalent circuit model can be various known to those skilled in the art. In one example of the present invention, Figure 2 As shown, the equivalent circuit model includes the potential source , the first resistor , the second resistor and the first capacitor . The first resistor One end and the potential source The positive connection of the second resistor One end of the first resistor The other end of the first capacitor is connected One end of the second resistor One end of the first capacitor is connected The other end of the second resistor The equivalent circuit model is the equivalent circuit diagram of a single battery.

[0062] In this embodiment, the manner of obtaining the voltage and current of each branch of the battery pack according to the bond graph model of the single cell and the bond graph model of the battery pack may be various methods known to those skilled in the art. In a preferred example of the present invention, the voltage and current of each branch of the battery pack are obtained by Kirchhoff's voltage law, Kirchhoff's current law and other physical relationships, including:

[0063] According to formulas (1) to (6), the voltage and current of each branch of the battery pack are obtained.

[0064] , (1)

[0065] , (2)

[0066] , (3)

[0067] , (4)

[0068] , (5)

[0069] , (6)

[0070] in, For the Row, No. The ohmic internal resistance of the first resistor of the column, For the Row, No. The polarization internal resistance of the second resistor of the column, For the Row, No. The polarization capacitance of the first capacitor of the column, , , , , and are the currents on each branch of the bond graph model, , , , , and are the voltages on each branch of the bond graph model, is the differential of the voltage of branch number 5, For the Row, No. The potential source of the column, , , is an integer number, is the total number of parallel-connected single-cell rows, is the total number of series-connected single-cell batteries. In the present invention, the equivalent ohmic internal resistance is used to characterize the battery aging, and the equivalent polarization capacitance and polarization resistance are used to characterize the battery operating condition, so that the aging and operating condition of the single-cell battery can be evaluated. Figure 3 As shown, Figure 3 For the Row, No. The bond graph model of the single battery in the column has 6 branches, of which the branch numbered 6 is the output branch. .

[0071] In this implementation, the method of deriving and parsing the redundant relationship using the bond graph model may be various methods known to those skilled in the art. In one example of the present invention, specifically, the redundant relationship is parsed based on voltage and current, including:

[0072] According to formula (7), the redundant relationship is analyzed:

[0073] , (7)

[0074] in, Branch and The voltage, is the redundant relationship of the node “1” in the first column, is the voltage of the branch numbered 6 of each single cell in column 1. Figure 4 As shown, Figure 4 is the bond graph model of the battery pack. The battery pack has string, And, which is equivalent to List, Row, in the figure is the equivalent load resistance, For the The unbalanced resistance of the series branch must be consistent with the redundancy relationship In Make a distinction.

[0075] In this embodiment, when the battery pack is working, the voltage and current of each branch can be measured by the sensor to calculate the fault feature matrix. Therefore, the fault feature matrix can be constructed according to the redundancy relationship to locate the faulty single battery, including:

[0076] According to formula (8), the fault feature matrix is ​​constructed:

[0077] , (8)

[0078] in, is the fault feature matrix, , …, , …, is the fault variable, for Each column has , , and Four parameters.

[0079] In this implementation, there may be various methods known to those skilled in the art for further confirming the faulty single cell. In one example of the present invention, a fault feature matrix may be constructed based on the redundancy relationship to locate the faulty single cell, such as: Figure 5 Specifically, it includes:

[0080] In step S61, the fault variable of each single cell is determined according to formula (9):

[0081] , (9)

[0082] in, is the fault variable, For the Redundant Relationship , For the Fault parameters.

[0083] In step S62, the faulty single cell is determined according to the fault variable. It can identify which column of single cells is faulty, and then It is determined that the single cell in the row of the column is a faulty single cell, thereby effectively identifying and locating the faulty single cell in the battery pack.

[0084] In this embodiment, further, when the fault variable is 1, it is determined that the corresponding single cell is a faulty single cell.

[0085] On the other hand, the present invention provides a battery pack fault diagnosis system, which includes a processor configured to execute any of the diagnostic methods described above.

[0086] In still another aspect, the present invention provides a computer-readable storage medium storing instructions, wherein the instructions are used to be read by a machine so as to enable the machine to execute any of the above-mentioned diagnostic methods.

[0087] Through the above technical scheme, the present invention provides a battery pack fault diagnosis method, system and storage medium, which uses equivalent ohmic internal resistance to characterize battery aging, uses equivalent polarization capacitance and polarization resistance to characterize battery operating conditions, and establishes a system bond graph model to analyze redundant relationships to achieve fault diagnosis. Compared with the prior art, the bond graph modeling method used in the present invention clearly describes each single cell of the battery pack. When performing fault diagnosis, this method can effectively identify and locate faulty single cells in the battery pack, thereby improving the reliability and safety of the battery pack.

[0088] The optional implementation modes of the examples of the present invention are described in detail above in conjunction with the accompanying drawings; however, the implementation modes of the present invention are not limited to the specific details in the above implementation modes; within the technical concept of the implementation modes of the present invention, a variety of simple modifications can be made to the technical solutions of the implementation modes of the present invention, and these simple modifications all belong to the protection scope of the implementation modes of the present invention.

[0089] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not further describe various possible combinations.

[0090] Those skilled in the art can understand that all or part of the steps in the above-mentioned implementation method can be completed by instructing the relevant hardware through a program, and the program is stored in a storage medium, including several instructions to enable a (which can be a single-chip microcomputer, chip, etc.) or a processor to execute all or part of the steps of the method described in each implementation of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0091] In addition, various different embodiments of the embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the embodiments of the present invention, they should also be regarded as the contents disclosed in the embodiments of the present invention.

Claims

1. A battery pack fault diagnosis method, characterized in that: The diagnostic method comprises: Construct an equivalent circuit model of a single battery; Constructing a bonding graph model of the single cell according to the equivalent circuit model; Constructing a bonding graph model of a battery pack according to the bonding graph model of the single battery; Obtaining the voltage and current of each branch of the battery pack according to the bonding graph model of the single battery and the bonding graph model of the battery pack; Resolving a redundancy relationship based on the voltage and current; Constructing a fault feature matrix according to the redundant relationship to locate the faulty single battery; The equivalent circuit model includes: Potential source; a first resistor, one end of which is connected to the positive electrode of the potential source; a second resistor, one end of the second resistor being connected to the other end of the first resistor; a first capacitor, one end of the first capacitor being connected to one end of the second resistor, and the other end of the first capacitor being connected to the other end of the second resistor; The voltage and current of each branch of the battery pack are obtained according to the bonding graph model of the single battery and the bonding graph model of the battery pack, including: According to formulas (1) to (6), the voltage and current of each branch of the battery pack are obtained. ，（1） ，（2） ，（3） ，（4） ，（5） ，（6） in, For the Row, No. The ohmic internal resistance of the first resistor of the column, For the Row, No. The polarization internal resistance of the second resistor of the column, For the Row, No. The polarization capacitance of the first capacitor of the column, , , , , and are the currents on each branch of the bond graph model, , , , , and are the voltages on each branch of the bond graph model, is the differential of the voltage of branch number 5, For the Row, No. The potential source of the column, , , is an integer number, is the total number of parallel-connected single-cell rows, is the total number of series-connected single-cell columns; Resolving a redundancy relationship based on the voltage and current includes: According to formula (7), the redundant relationship is analyzed: ， （7） in, Branch and The voltage, is the redundant relationship of the node "1" in the first column, is the voltage of the branch numbered 6 of each single cell in column 1; Constructing a fault feature matrix according to the redundant relationship to locate the faulty single battery, including: According to formula (8), the fault feature matrix is ​​constructed: ，（8） in, is the fault feature matrix, , …, , …, is the fault variable, for Each column has , , and Four parameters.

2. The diagnostic method according to claim 1, characterized in that Constructing a fault feature matrix according to the redundant relationship to locate the faulty single battery, including: According to formula (9), the fault variable of each single cell is determined: ，（9） in, is the fault variable, For the Redundant Relationship , For the Fault parameters; The failed single battery is determined according to the fault variable.

3. The diagnostic method according to claim 2, characterized in that Determining the faulty single cell according to the fault variable includes, when the fault variable is 1, determining that the corresponding single cell is the faulty single cell.

4. A battery pack fault diagnosis system, characterized in that: The system comprises a processor configured to execute the diagnostic method according to any one of claims 1 to 3.

5. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores instructions, and the instructions are used to be read by a machine so that the machine executes the diagnosis method according to any one of claims 1 to 3.

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