A battery cell SOC low fault diagnosis method and system and a readable storage medium

Abstract

The embodiment of the application provides a battery cell SOC low fault diagnosis method, system and readable storage medium, the method comprises determining the total voltage data corresponding to each battery cluster in a lithium battery energy storage system, wherein each battery cluster comprises a plurality of battery cells; according to the total voltage data corresponding to the corresponding battery cluster, and the total number of battery cells included, the average voltage value corresponding to each battery cluster is calculated; for each battery cell in the same battery cluster, according to the average voltage value, the preset single cell voltage calibration value, the preset voltage difference value and the single cell voltage value of the battery cell in the preset working stage, the fault decision condition is determined; when it is determined that the corresponding target battery cell meets the fault decision condition, the fault diagnosis result that the battery cell SOC is low and there is a fault is output. The false positive rate of the SOC low fault diagnosis can be reduced by using the method.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of SOC management, in particular to a battery cell SOC low fault diagnosis method and system and a readable storage medium. BACKGROUND

[0002] The direct current side of a lithium battery energy storage system is composed of multiple groups of battery cells connected in series. If the SOC (State of Charge) of a single battery cell in a certain battery cluster decreases to 0 during the discharging process of the lithium battery energy storage system, not only the battery cluster will stop discharging, but also all the battery clusters under the same lithium battery energy storage system will stop discharging, otherwise it is extremely likely to cause over-discharge of the single battery cell and eventually cause a serious safety accident. Therefore, the minimum single battery cell SOC directly determines the overall efficiency of the lithium battery energy storage system.

[0003] The low SOC of the single battery cell is a long-term accumulation. Once the low SOC occurs, it may be a special situation in the discharging process, and it can be restored after being fully charged. In the existing technical solution, whether the lithium battery SOC is low and inconsistent is usually judged based on the SOC at a certain moment, which will also lead to high false positive rate and low accuracy. SUMMARY

[0004] The purpose of the embodiments of the application is to provide a battery cell SOC low fault diagnosis method, system and readable storage medium, which can reduce the false positive rate of the SOC low fault diagnosis.

[0005] The application further provides a battery cell SOC low fault diagnosis method, comprising the following steps:

[0006] Determine the total voltage data corresponding to each battery cluster in the lithium battery energy storage system, wherein each battery cluster includes a plurality of battery cells;

[0007] According to the total voltage data corresponding to the corresponding battery cluster and the total number of battery cells included, calculate the average voltage value corresponding to each battery cluster;

[0008] For each battery cell in the same battery cluster, determine a fault decision condition according to the average voltage value, a preset single cell voltage calibration value, a preset voltage difference value, and a single cell voltage value of the battery cell in a preset working stage; the working stage includes at least one of a discharging stage, a standing stage after discharging, and a charging stage;

[0009] When it is determined that the corresponding target battery cell satisfies the fault decision condition, output a fault diagnosis result representing that the SOC of the battery cell is low and there is a fault.

[0010] Secondly, embodiments of this application also provide a fault diagnosis system for low SOC of a single battery cell, the system comprising a data acquisition module, a first calculation module, a second calculation module, and a fault judgment module, wherein:

[0011] The data acquisition module is used to determine the total voltage data corresponding to each battery cluster in the lithium battery energy storage system, wherein each battery cluster includes multiple battery cells.

[0012] The first calculation module is used to calculate the average voltage value corresponding to each battery cluster based on the total voltage data corresponding to the corresponding battery cluster and the total number of battery cells included.

[0013] The second calculation module is used to determine fault judgment conditions for each battery cell in the same battery cluster based on the average voltage value, a preset cell voltage calibration value, a preset voltage difference value, and the cell voltage value of the battery cell in a preset working stage; the working stage includes at least one of a discharge stage, a post-discharge rest stage, and a charging stage.

[0014] The fault judgment module is used to output a fault diagnosis result indicating that the SOC of the corresponding target battery cell is low and there is a fault when it is determined that the corresponding target battery cell meets the fault judgment condition.

[0015] Thirdly, embodiments of this application also provide a readable storage medium, which includes a battery cell low SOC fault diagnosis method program. When the battery cell low SOC fault diagnosis method program is executed by a processor, it implements the steps of a battery cell low SOC fault diagnosis method as described in any of the above claims.

[0016] As can be seen from the above, the battery cell low SOC fault diagnosis method, system and readable storage medium provided in this application analyze the voltage characteristics of the battery cell throughout the entire charging and discharging stage. Compared with the prior art which only analyzes the SOC at a certain moment, this method can effectively improve the overall diagnostic accuracy of the battery cell, improve the overall operating efficiency of the lithium battery energy storage system, and reduce the false alarm rate of low SOC fault diagnosis.

[0017] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing embodiments of this application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart of a method for diagnosing low SOC of a single battery cell provided in an embodiment of this application.

[0020] Figure 2 This is a schematic diagram of a low SOC fault diagnosis system for a single battery cell provided in an embodiment of this application. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0022] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0023] Please refer to Figure 1 , Figure 1 This is a flowchart illustrating a method for diagnosing a low SOC (State of Charge) fault in a single battery cell, as described in some embodiments of this application. The method is illustrated using an example of its application to a computer device (specifically, a terminal or server; the terminal can be, but is not limited to, various personal computers, laptops, smartphones, tablets, and portable wearable devices; the server can be a standalone server or a server cluster composed of multiple servers). The steps include:

[0024] S101. Determine the total voltage data corresponding to each battery cluster in the lithium battery energy storage system, wherein each battery cluster includes multiple battery cells.

[0025] Specifically, when the computer device confirms that it has successfully connected to the lithium battery energy storage system, it acquires the voltage data V of each battery cell in the lithium battery energy storage system, and determines the total voltage data corresponding to each battery cluster based on the voltage data V determined above.

[0026] In one embodiment, when it is determined that the corresponding battery cluster A includes B battery cells, then when the voltage data V of each battery cell is known, the total voltage data of battery cluster A is B*V. Of course, the current embodiment is not limited to the above calculation method, and the above formula can be adjusted according to actual calculation needs. This application embodiment does not limit this.

[0027] S102. Based on the total voltage data corresponding to the corresponding battery cluster and the total number of battery cells included, calculate the average voltage value corresponding to each battery cluster.

[0028] Specifically, based on the total voltage data corresponding to the corresponding battery cluster and the total number of battery cells included, the average voltage value corresponding to each battery cluster is calculated, including: dividing the total voltage data corresponding to the corresponding battery cluster and the total number of battery cells included, and determining the average voltage value corresponding to each battery cluster based on the division result.

[0029] In one embodiment, the computer device will calculate the average voltage value V corresponding to each battery cluster, on a cluster-by-cluster basis. avg =V 总 / n. Where V avg This represents the average voltage of the battery cluster, V. 总 This represents the total voltage of the battery cluster, and n represents the total number of cells in the battery cluster, i.e., the total number of individual battery cells.

[0030] S103. For each battery cell in the same battery cluster, determine the fault judgment conditions based on the average voltage value, the preset cell voltage calibration value, the preset voltage difference value, and the cell voltage value of the battery cell in the preset working stage; the working stage includes at least one of the discharge stage, the post-discharge rest stage, and the charging stage.

[0031] S104. When it is determined that the corresponding target battery cell meets the fault judgment condition, output the fault diagnosis result indicating that the SOC of the battery cell is low and there is a fault.

[0032] Specifically, when the computer equipment is connected to the user terminal, it will output the fault diagnosis results to the user terminal when it determines that the corresponding target battery cell meets the fault judgment conditions, so that the user terminal can keep abreast of the real-time operation of the lithium battery energy storage system and troubleshoot the fault in a timely manner.

[0033] In one embodiment, the computer device has a built-in display screen, audio equipment, and lighting equipment. The computer device can also display fault diagnosis results through the built-in display screen and / or provide voice prompts through the built-in audio equipment. Of course, the computer device can also display fault diagnosis results in other ways. For example, when a fault diagnosis result is determined to be output, the built-in lighting equipment can be triggered to display lights, indicating to the user that there is a current operational fault. This application embodiment does not limit the display method of fault diagnosis results.

[0034] As can be seen from the above, the battery cell low SOC fault diagnosis method provided in this application analyzes the voltage characteristics of the battery cell throughout the entire charging and discharging phase. Compared with the prior art which only analyzes the SOC at a certain moment to diagnose the lowest battery cell SOC, this method can effectively improve the overall diagnostic accuracy of the battery cell, improve the overall operating efficiency of the lithium battery energy storage system, and reduce the false alarm rate of low SOC fault diagnosis.

[0035] In one embodiment, the fault determination condition includes: during the discharge phase, when it is determined that the average voltage value is greater than or equal to the single-cell voltage calibration value, and within a consecutive preset number of times, there exists a voltage difference between the average voltage and the single-cell voltage value that is greater than or equal to a preset first multiple of the voltage difference, a first fault determination condition.

[0036] Specifically, during the discharge phase, the computer equipment performs the following analysis on each individual cell within the same battery cluster: when the V corresponding to the respective cell is determined... avg When ≥M, and V exists consecutively multiple times (e.g., 3 times): avg -V e If the voltage is ≥N, then the battery cell is considered to meet the first fault judgment condition. In this case, it can be determined that the voltage during the discharge phase of the battery cell is significantly low, and it can be preliminarily determined that the state of charge (SOC) of the battery cell is low, indicating a fault. Wherein, V e M represents the individual cell voltage value in the current discharge analysis phase, M is a fixed calibration value of an individual cell voltage (i.e., a preset individual cell voltage calibration value), and N is a fixed voltage difference value.

[0037] During the discharge phase, when it is determined that the average voltage is less than the rated value of the single cell voltage, and, after a preset number of consecutive cycles, there exists a second fault judgment condition where the voltage difference between the average voltage and the single cell voltage value is greater than or equal to a preset second multiple of the voltage difference; wherein, the second multiple is greater than the first multiple.

[0038] Specifically, during the discharge phase, the computer equipment also performs the following analysis on each individual cell within the same battery cluster: when the V corresponding to the respective cell is determined... avg When <M, and V exists consecutively multiple times. avg -Ve If the value is ≥2N, the battery cell is considered to meet the second fault judgment condition. In the current embodiment, the value of the second multiple is 2. Of course, the setting of the second multiple is not limited to this value, and this application embodiment does not limit it.

[0039] During the post-discharge resting phase, and within a predetermined number of consecutive preset times, there exists a third fault judgment condition where the voltage difference between the average voltage and the individual cell voltage is greater than or equal to a preset third multiple of the voltage difference; wherein, the second multiple is greater than the third multiple.

[0040] Specifically, during the post-discharge resting phase, the computer equipment also performs the following analysis on each individual cell within the same battery cluster: when it is determined that V appears consecutively multiple times... avg -V e When the value is ≥0.75N, the corresponding battery cell is considered to meet the third fault judgment condition. In the current embodiment, the value of the third multiple is 0.75. Of course, the setting of the third multiple is not limited to this value, and this application embodiment does not limit it.

[0041] The fourth fault determination condition is that during the charging phase, the individual cell voltage is less than the average voltage, and the voltage difference between the individual cell voltage and the average voltage is greater as the charging process nears its end.

[0042] Specifically, during the charging phase, the computer equipment also performs the following analysis on each individual cell within the same battery cluster: when the cell voltage V corresponding to the given cell is determined... e Below average voltage V avg Furthermore, as the charging process nears its end, the individual cell voltage V... e and average voltage V avg The greater the pressure difference between them, the more likely the corresponding battery cell meets the fourth fault judgment condition.

[0043] In the above embodiments, the voltage characteristics of each battery cell during the charging and discharging process are fully analyzed, rather than the voltage characteristics at a certain moment. This helps to improve the accuracy of the overall diagnosis and reduce the false alarm rate of low SOC fault diagnosis.

[0044] In one embodiment, in step S104, when it is determined that the corresponding target battery cell meets the fault judgment condition, a fault diagnosis result indicating that the SOC of the battery cell is low and there is a fault is output, including: when it is determined that the corresponding target battery cell meets any one of the first fault judgment condition to the fourth fault judgment condition within multiple consecutive analysis cycles, the fault diagnosis result indicating that the SOC of the target battery cell is low and there is a fault is output to the corresponding terminal device, so that the terminal device can display the information.

[0045] Specifically, when the computer equipment determines that a target battery cell meets any one of the first to fourth fault judgment conditions, it determines that the voltage of the target battery cell is significantly low in the late stage of discharge and also low in the late stage of charging. This preliminarily indicates that the target battery cell has a low State of Charge (SOC) and is faulty. Furthermore, if the computer equipment determines that the target battery cell exhibits the above characteristics within a preset analysis cycle (e.g., three analysis cycles), it ultimately diagnoses that the target battery cell has a low SOC fault and requires timely repair to ensure the normal operation of the lithium battery energy storage system.

[0046] Please refer to Figure 2 As shown in the figure, this application embodiment also provides a battery cell low SOC fault diagnosis system 200. The system 200 includes a data acquisition module 201, a first calculation module 202, a second calculation module 203, and a fault judgment module 204, wherein:

[0047] The data acquisition module 201 is used to determine the total voltage data corresponding to each battery cluster in the lithium battery energy storage system, wherein each battery cluster includes multiple battery cells.

[0048] The first calculation module 202 is used to calculate the average voltage value corresponding to each battery cluster based on the total voltage data corresponding to the corresponding battery cluster and the total number of battery cells included.

[0049] The second calculation module 203 is used to determine fault judgment conditions for each battery cell in the same battery cluster based on the average voltage value, the preset cell voltage calibration value, the preset voltage difference value, and the cell voltage value of the battery cell in the preset working stage; the working stage includes at least one of the discharge stage, the post-discharge rest stage, and the charging stage.

[0050] The fault judgment module 204 is used to output a fault diagnosis result indicating that the SOC of the corresponding target battery cell is low and there is a fault when it is determined that the corresponding target battery cell meets the fault judgment conditions.

[0051] In one embodiment, the first calculation module 202 is further configured to perform a division calculation on the total voltage data corresponding to the corresponding battery cluster and the total number of battery cells included, and determine the average voltage value corresponding to each battery cluster based on the obtained division result.

[0052] In one embodiment, the second calculation module 203 is further configured to: during the discharge phase, when it is determined that the average voltage value is greater than or equal to the single-cell voltage calibration value, and within a consecutive preset number of times, there exists a voltage difference between the average voltage and the single-cell voltage value that is greater than or equal to a preset first multiple of the voltage difference; during the discharge phase, when it is determined that the average voltage is less than the single-cell voltage calibration value, and within a consecutive preset number of times, there exists a voltage difference between the average voltage and the single-cell voltage value that is greater than or equal to a preset second multiple of the voltage difference; wherein the second multiple is greater than the first multiple; during the post-discharge resting phase, and within a determined consecutive preset number of times, there exists a voltage difference between the average voltage and the single-cell voltage value that is greater than or equal to a preset third multiple of the voltage difference; wherein the second multiple is greater than the third multiple; and during the charging phase, when the single-cell voltage value is less than the average voltage, and near the end of charging, a fourth fault judgment condition is established whereby the voltage difference between the single-cell voltage value and the average voltage is greater.

[0053] In one embodiment, the fault judgment module 204 is further configured to output a fault diagnosis result indicating that the target battery cell has a low SOC and is faulty to the corresponding terminal device when it is determined that the corresponding target battery cell meets any one of the first fault judgment conditions to the fourth fault judgment conditions within multiple consecutive analysis cycles, so that the terminal device can display the information.

[0054] As can be seen from the above, the battery cell low SOC fault diagnosis system provided in this application analyzes the voltage characteristics of the battery cell throughout the entire charging and discharging phase. Compared with the prior art which only analyzes the SOC at a certain moment, the system can effectively improve the overall diagnostic accuracy of the battery cell, improve the overall operating efficiency of the lithium battery energy storage system, and reduce the false alarm rate of low SOC fault diagnosis.

[0055] This application provides a storage medium in which, when the computer program is executed by a processor, the method in any optional implementation of the above embodiments is performed. The storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0056] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0057] Furthermore, the units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0058] Furthermore, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0059] In this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, without necessarily requiring or implying any such actual relationship or order between these entities or operations.

[0060] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for diagnosing low SOC (State of Charge) faults in battery cells, characterized in that, Includes the following steps: The voltage data of each battery cell in the lithium battery energy storage system is obtained, and the total voltage data corresponding to each battery cluster is determined. Each battery cluster includes multiple battery cells. Based on the total voltage data corresponding to the corresponding battery cluster and the total number of battery cells included, calculate the average voltage value corresponding to each battery cluster. For each battery cell in the same battery cluster, fault judgment conditions are determined based on the average voltage value, the preset cell voltage calibration value, the preset voltage difference value, and the cell voltage value of the battery cell in the preset working stage; the working stage includes at least one of the following: discharge stage, post-discharge rest stage, and charging stage. During the discharge phase, when it is determined that the average voltage value is greater than or equal to the single-cell voltage calibration value, and within a consecutive preset number of times, there exists a voltage difference between the average voltage and the single-cell voltage value that is greater than or equal to the voltage difference value of a preset first multiple, a first fault judgment condition is established. During the discharge phase, when it is determined that the average voltage is less than the single-cell voltage calibration value, and, after a preset number of consecutive tests, there exists a second fault judgment condition where the voltage difference between the average voltage and the single-cell voltage value is greater than or equal to a preset second multiple of the voltage difference; wherein, the second multiple is greater than the first multiple; During the post-discharge resting phase, and within a predetermined number of consecutive preset times, there exists a third fault judgment condition where the voltage difference between the average voltage and the individual cell voltage value is greater than or equal to a preset third multiple of the voltage difference; wherein, the second multiple is greater than the third multiple; During the charging phase, the individual cell voltage value is less than the average voltage, and the voltage difference between the individual cell voltage value and the average voltage is greater as the charging phase approaches its end; this is the fourth fault determination condition. When it is determined that the corresponding target battery cell meets the fault judgment condition, a fault diagnosis result is output indicating that the SOC of the battery cell is low and there is a fault.

2. The method according to claim 1, characterized in that, The step of calculating the average voltage value corresponding to each battery cluster based on the total voltage data corresponding to the corresponding battery cluster and the total number of battery cells included includes: The total voltage data corresponding to the corresponding battery cluster and the total number of battery cells included are divided, and the average voltage value corresponding to each battery cluster is determined based on the division result.

3. The method according to claim 1, characterized in that, When it is determined that the corresponding target battery cell meets the fault judgment condition, a fault diagnosis result is output indicating that the battery cell has a low SOC and a fault exists, including: When it is determined that within multiple consecutive analysis cycles, the corresponding target battery cell meets any one of the first to the fourth fault judgment conditions, a fault diagnosis result indicating that the target battery cell has a low SOC is output to the corresponding terminal device for information display.

4. A fault diagnosis system for low SOC of a single battery cell, characterized in that, The system includes a data acquisition module, a first calculation module, a second calculation module, and a fault determination module, wherein: The data acquisition module is used to acquire the voltage data of each battery cell in the lithium battery energy storage system and determine the total voltage data corresponding to each battery cluster, wherein each battery cluster includes multiple battery cells. The first calculation module is used to calculate the average voltage value corresponding to each battery cluster based on the total voltage data corresponding to the corresponding battery cluster and the total number of battery cells included. The second calculation module is used to determine fault judgment conditions for each battery cell in the same battery cluster based on the average voltage value, a preset cell voltage calibration value, a preset voltage difference value, and the cell voltage value of the battery cell in a preset operating stage; the operating stage includes at least one of a discharge stage, a post-discharge rest stage, and a charging stage; in the discharge stage, when it is determined that the average voltage value is greater than or equal to the cell voltage calibration value, and within a preset number of consecutive times, there exists a voltage difference between the average voltage and the cell voltage value that is greater than or equal to the voltage difference value of a preset first multiple, a first fault judgment condition is met; in the discharge stage, when it is determined that the average voltage is less than the cell voltage calibration value, a fault judgment condition is met. During voltage calibration, a second fault judgment condition is established where, within a predetermined number of consecutive cycles, the voltage difference between the average voltage and the individual cell voltage value is greater than or equal to a predetermined second multiple of the voltage difference; wherein the second multiple is greater than the first multiple. During the post-discharge resting phase, a third fault judgment condition is established where, within a predetermined number of consecutive cycles, the voltage difference between the average voltage and the individual cell voltage value is greater than or equal to a predetermined third multiple of the voltage difference; wherein the second multiple is greater than the third multiple. During the charging phase, a fourth fault judgment condition is established where the individual cell voltage value is less than the average voltage, and, as the charging nears its end, the voltage difference between the individual cell voltage value and the average voltage increases. The fault judgment module is used to output a fault diagnosis result indicating that the SOC of the corresponding target battery cell is low and there is a fault when it is determined that the corresponding target battery cell meets the fault judgment condition.

5. The system according to claim 4, characterized in that, The first calculation module is also used to divide the total voltage data corresponding to the corresponding battery cluster and the total number of battery cells included, and determine the average voltage value corresponding to each battery cluster based on the division result.

6. The system according to claim 4, characterized in that, The fault judgment module is also used to output a fault diagnosis result indicating that the target battery cell has a low SOC and is faulty when it is determined that the corresponding target battery cell meets any one of the first fault judgment conditions to the fourth fault judgment conditions within multiple consecutive analysis cycles, so that the terminal device can display the information.

7. A readable storage medium, characterized in that, The readable storage medium includes a method program for diagnosing low SOC of a battery cell, which, when executed by a processor, implements the steps of the method as described in any one of claims 1 to 3.

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