Method and device for estimating voltage of failed single battery and vehicle

Abstract

The invention discloses a voltage estimation method and device for a failed single battery and a vehicle. The method comprises the steps that the number of failed single batteries in a battery pack is determined; when the number of the failed single batteries is smaller than or equal to a preset threshold value, the charge-discharge state and the charge state of the battery pack are obtained; and when the battery pack is in the charging state and the state of charge is greater than or equal to a first preset electric quantity threshold, or when the battery pack is in the discharging state and the state of charge is less than or equal to a second preset electric quantity threshold, determining a target voltage value of a failed single battery based on the voltage values of non-failed single batteries in the battery pack. According to the method provided by the invention, voltage acquisition faults caused by voltage acquisition hardware problems in practical application can be effectively avoided, the influence caused by abnormal voltage acquisition values is reduced, the problem of overcharge and overdischarge of the battery is avoided, and the driving safety is improved.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and particularly relates to a method for estimating the voltage of a failed single battery, a vehicle, and a device for estimating the voltage of a failed single battery. Background Art

[0002] The single-cell voltage in a battery management system is collected by a battery sampling chip (Analog Front End, AFE). In the prior art, when collecting the single-cell voltage based on the battery sampling chip, if the collection is abnormal, the main reasons include that the single-cell voltage collection line has a disconnection fault, the single-cell voltage collection line interface is not connected in the correct order, the single-cell voltage collection chip has an abnormal collection, etc. In all these cases, an invalid voltage value will be collected, which will trigger a single-cell voltage collection fault and immediately cut off the high voltage to stop the vehicle, affecting the driver experience.

[0003] Currently, a method for processing the single-cell voltage when the single-cell collection is disconnected is proposed in the related art. First, identify the number of all abnormal single cells. If the number of effective single cells <= 5, it is considered that the number of single cells is too small and no processing is performed; otherwise, judge the single-cell numbers that meet the preset interval, calculate the single-cell voltage values in the current cycle and the previous cycle, and calculate the average voltage value of all effective single-cell collections and the difference between each single-cell voltage value and the average voltage value. If the number of effective single cells > 2, use the average value of all valid values at this time + (the difference between the voltage in the previous cycle and the average value at the previous moment) to replace the single-cell abnormal value. If <= 2, use the valid single-cell voltage at the previous moment to replace the abnormal voltage value collected in the current cycle. There is also a method of using the single-cell voltage at the previous moment to replace the abnormal voltage collected in this cycle. However, the above methods ignore the voltage change between this time and the previous moment, resulting in the voltage value used this time being actually higher, causing a large gap between the current power estimation and the actual value, and not considering the problem that overcharging or over-discharging of this single-cell may occur at the end of charge or discharge, which may even seriously affect driving safety in severe cases. Summary of the Invention

[0004] This application aims to solve at least one of the technical problems in the related art to some extent. For this purpose, the first object of this application is to propose a method for estimating the voltage of a failed single battery cell, determine the number of failed single battery cells in a battery pack, and when the number of failed single battery cells is less than or equal to a preset threshold, obtain the charge-discharge state and state of charge of the battery pack. When the battery pack is in a charging state and the state of charge is greater than or equal to the first preset power threshold, or when the battery pack is in a discharging state and the state of charge is less than or equal to the second preset power threshold, determine the target voltage value of the failed single battery cell based on the voltage values of the non-failed single battery cells in the battery pack. Thus, it can effectively avoid voltage acquisition failures caused by problems in voltage acquisition hardware in practical applications, reduce the impact of abnormal voltage acquisition values, and avoid overcharging and over-discharging problems of the battery, improving driving safety.

[0005] The second object of this application is to propose a vehicle.

[0006] The third object of this application is to propose a device for estimating the voltage of a failed single battery cell.

[0007] To achieve the above object, an embodiment of the first aspect of this application proposes a method for estimating the voltage of a failed single battery cell, the method includes: determining the number of failed single battery cells in a battery pack; when the number of failed single battery cells is less than or equal to a preset threshold, obtaining the charge-discharge state and state of charge of the battery pack; when the battery pack is in a charging state and the state of charge is greater than or equal to the first preset power threshold, or when the battery pack is in a discharging state and the state of charge is less than or equal to the second preset power threshold, determining the target voltage value of the failed single battery cell based on the voltage values of the non-failed single battery cells in the battery pack.

[0008] According to the method for estimating the voltage of a failed single battery cell of the embodiment of this application, determine the number of failed single battery cells in a battery pack, when the number of failed single battery cells is less than or equal to a preset threshold, obtain the charge-discharge state and state of charge of the battery pack, when the battery pack is in a charging state and the state of charge is greater than or equal to the first preset power threshold, or when the battery pack is in a discharging state and the state of charge is less than or equal to the second preset power threshold, determine the target voltage value of the failed single battery cell based on the voltage values of the non-failed single battery cells in the battery pack. Thus, this method can effectively avoid voltage acquisition failures caused by problems in voltage acquisition hardware in practical applications, reduce the impact of abnormal voltage acquisition values, and avoid overcharging and over-discharging problems of the battery, improving driving safety.

[0009] In addition, the method for estimating the voltage of a failed single battery cell according to the above embodiment of this application may also have the following additional technical features:

[0010] According to an embodiment of the present application, determining the target voltage value of the failed single battery based on the voltage values of the unfailed single batteries in the battery pack includes: when the battery pack is in a charging state and the state of charge is greater than or equal to a first preset power threshold, taking the maximum voltage value of the unfailed single batteries in the battery pack as the target voltage value of the failed single battery; when the battery pack is in a discharging state and the state of charge is less than or equal to a second preset power threshold, taking the minimum voltage value of the unfailed single batteries in the battery pack as the target voltage value of the failed single battery.

[0011] According to an embodiment of the present application, the method further includes: when the battery pack is in a charging state and the state of charge is less than the first preset power threshold, or when the battery pack is in a discharging state and the state of charge is greater than the second preset power threshold, or when the battery pack is in a non-charging state or a non-discharging state, determining the target voltage value of the failed single battery based on the single battery voltage values of the battery pack in the previous acquisition cycle.

[0012] According to an embodiment of the present application, determining the target voltage value of the failed single battery based on the single battery voltage values of the battery pack in the previous acquisition cycle includes: respectively obtaining the voltage differences between the voltage value of the failed single battery in the previous acquisition cycle and the voltage values of each single battery other than the failed single battery in the previous acquisition cycle; taking the single batteries within the previous acquisition cycle corresponding to the voltage differences less than a preset voltage threshold as a reference single battery set; obtaining the minimum distance between the positions of each reference single battery in the reference single battery set and the position of the failed single battery; taking the voltage value of the reference single battery corresponding to the minimum distance as the target voltage value of the failed single battery.

[0013] According to an embodiment of the present application, the method further includes: when the battery pack is in a charging state and the state of charge is greater than or equal to a third preset power threshold, controlling the battery pack to stop charging, where the third preset power threshold is greater than the first preset power threshold; when the battery pack is in a discharging state and the state of charge is less than or equal to a fourth preset power threshold, controlling the battery pack to stop discharging, where the fourth preset power threshold is less than the second preset power threshold.

[0014] According to an embodiment of the present application, the method further includes: determining the fault type of the failed single battery based on the local outlier factor algorithm; determining the fault reporting and handling strategy based on the fault type.

[0015] According to an embodiment of the present application, the fault type includes a disconnection fault or a harness connection reversal fault. The determining of the fault reporting and handling strategy based on the fault type includes: when the fault type is the disconnection fault or the harness connection reversal fault, obtaining, within the single power-on time, the first ratio of the number of single-cell battery failures in the battery pack to the total number of acquisitions; if the first ratio is greater than the first preset ratio, reporting the fault type and sending a maintenance reminder; if the first ratio is greater than or equal to the second preset ratio and less than or equal to the first preset ratio, storing and counting the current fault type, and when the count exceeds the first preset number, reporting the fault type and sending a maintenance reminder; if the first ratio is less than the second preset ratio, storing the current fault type.

[0016] According to an embodiment of the present application, the fault type includes an AFE acquisition fault. The determining of the fault reporting and handling strategy based on the fault type includes: when the fault type is the AFE acquisition fault and the fault acquisition rate of the AFE chip is greater than or equal to the preset chip failure rate, obtaining, within the single power-on time, the second ratio of the number of single-cell battery failures in the battery pack to the total number of acquisitions; if the second ratio is greater than the third preset ratio, reporting the fault type and sending a maintenance reminder; if the second ratio is greater than or equal to the fourth preset ratio and less than or equal to the third preset ratio, storing and counting the current fault type, and when the count exceeds the second preset number, reporting the fault type and sending a maintenance reminder; if the second ratio is less than the fourth preset ratio, storing the current fault type.

[0017] To achieve the above object, a vehicle proposed in the second aspect embodiment of the present application includes a memory, a processor, and a program stored in the memory and executable on the processor. When the processor executes the program, the voltage estimation method for the failed single-cell battery described above is implemented.

[0018] The vehicle according to the embodiment of the present application, by executing the voltage estimation method for the failed single-cell battery described above, can effectively avoid voltage acquisition failures caused by problems in the voltage acquisition hardware in actual applications, reduce the impact of abnormal voltage acquisition values, and avoid overcharging and over-discharging problems of the battery, thereby improving driving safety.

[0019] To achieve the above object, an embodiment of the third aspect of the present application provides a voltage estimation device for a failed single battery cell. The device includes: a determination module for determining the number of failed single battery cells in a battery pack; an acquisition module for acquiring the charge-discharge state and the state of charge of the battery pack when the number of failed single battery cells is less than or equal to a preset threshold; and an estimation module for determining a target voltage value of the failed single battery cell based on the voltage values of the non-failed single battery cells in the battery pack when the battery pack is in a charging state and the state of charge is greater than or equal to a first preset state-of-charge threshold, or when the battery pack is in a discharging state and the state of charge is less than or equal to a second preset state-of-charge threshold.

[0020] According to the voltage estimation device for a failed single battery cell of the embodiment of the present application, the determination module is used to determine the number of failed single battery cells in the battery pack, the acquisition module is used to acquire the charge-discharge state and the state of charge of the battery pack when the number of failed single battery cells is less than or equal to the preset threshold, and the estimation module is used to determine the target voltage value of the failed single battery cell based on the voltage values of the non-failed single battery cells in the battery pack when the battery pack is in a charging state and the state of charge is greater than or equal to the first preset state-of-charge threshold, or when the battery pack is in a discharging state and the state of charge is less than or equal to the second preset state-of-charge threshold. Thus, the device can effectively avoid voltage acquisition failures caused by problems in voltage acquisition hardware in practical applications, reduce the impact of abnormal voltage acquisition values, and avoid overcharging and over-discharging problems of the battery, improving driving safety.

[0021] Additional aspects and advantages of the present application will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a flowchart of a voltage estimation method for a failed single battery cell according to an embodiment of the present application;

[0023] Figure 2 is a flowchart of a voltage estimation method for a failed single battery cell according to a specific example of the present application;

[0024] Figure 3 is a block diagram of a vehicle according to an embodiment of the present application;

[0025] Figure 4 is a block diagram of a voltage estimation device for a failed single battery cell according to an embodiment of the present application. DETAILED DESCRIPTION

[0026] Embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present application, and should not be construed as limiting the present application.

[0027] The voltage estimation method for a failed single battery cell, a vehicle, and a voltage estimation device for a failed single battery cell proposed in the embodiments of the present application will be described below with reference to the accompanying drawings.

[0028] Figure 1 It is a flowchart of the voltage estimation method for a failed single battery cell according to an embodiment of the present application.

[0029] As Figure 1 shown, the voltage estimation method for a failed single battery cell in the embodiments of the present application may include the following steps:

[0030] S1. Determine the number of failed single battery cells in the battery pack.

[0031] S2. When the number of failed single battery cells is less than or equal to a preset threshold, obtain the charge-discharge state and state of charge of the battery pack. Here, the preset threshold can be determined according to the actual situation. For example, it can be determined based on the total number of single battery cells. For example, the preset threshold = total number of single battery cells / 8. For example, for 120 single battery cells, the threshold can be set to 15.

[0032] S3. When the battery pack is in a charging state and the state of charge is greater than or equal to a first preset state-of-charge threshold, or when the battery pack is in a discharging state and the state of charge is less than or equal to a second preset state-of-charge threshold, determine the target voltage value of the failed single battery cell based on the voltage values of the non-failed single battery cells in the battery pack. Here, the first preset state-of-charge threshold and the second preset state-of-charge threshold can be determined according to the actual situation. For example, the first preset state-of-charge threshold can be 95% (taking the full charge of the battery pack as 100%, accounting for 95% of the full charge), and the second preset state-of-charge threshold can be 5% (taking the full charge of the battery pack as 100%, accounting for 5% of the full charge).

[0033] Specifically, this application mainly addresses the problem of invalid values in the acquisition of single-cell voltages. During the charging and discharging process, when the battery pack is operating normally, if there are problems with voltage acquisition, in order not to affect the normal operation of the tram, it is necessary to estimate and process the invalid values, and make special treatments for the end stages of charging and discharging in combination with the actual situation of the battery pack. First, determine the number of failed single cells in the battery pack. The failed single cells may not work properly due to various reasons (such as overcharging, over-discharging, internal short circuit, etc.). For example, the BMS (Battery Management System) can continuously monitor parameters such as the voltage, current, and temperature of each single cell to identify those cells that exceed the normal operating range. If the parameters of a single cell do not match the preset safety range, it can be marked as failed.

[0034] After determining the number of failed single cells, judge the magnitude relationship between the number of failed single cells and a preset threshold. If the number of failed cells exceeds the preset threshold, it indicates that the current number of failed cells is relatively large, and other emergency measures need to be taken, such as cutting off the power supply or activating a safety protocol. If the number of failed single cells is less than or equal to the preset threshold, it means that the current number of failed single cells is within an acceptable range, and the charge-discharge state and state of charge of the battery pack can be obtained.

[0035] If the battery pack is in a charging state and the state of charge is greater than or equal to the first preset power threshold, or, if the battery pack is in a discharging state and the state of charge is less than or equal to the second preset power threshold, it indicates that the current battery pack is close to full charge during charging or close to being discharged during discharging. If a lower voltage value is used to replace the invalid value at the end of charging, it may cause the BMS system to misjudge the actual state of the battery, thinking that the battery is not fully charged, and thus continue charging. This may lead to overcharging of some single cells, damaging the battery and even causing safety problems. If a higher voltage value is used to replace the invalid value at the end of discharging, it may also cause the BMS system to misjudge the actual state of the battery, thinking that the battery has not been fully discharged, and thus continue discharging. This will lead to over-discharging of some single cells, damaging the battery and even causing safety problems. Therefore, in order to avoid overcharging or over-discharging problems, it is necessary to appropriately estimate the voltage of the failed single cell battery. The target voltage value of the failed single cell battery can be determined according to the voltage values of the non-failed single cell batteries in the battery pack. For example, when the battery pack is in a charging state and the state of charge is greater than or equal to the first preset power threshold, the larger voltage value among the voltage values of the non-failed single cell batteries currently close to the failed single cell battery can be selected as the target voltage value of the failed single cell battery. Or, the average value of the voltages of the non-failed single cell batteries can be calculated and added with a preset voltage value as the target voltage value of the failed single cell battery. Or, the maximum voltage value among the non-failed single cell batteries can be directly used as the target voltage value of the failed single cell battery. It should be noted that at the end of charging, the battery voltage should be close to its maximum safe voltage, and using a higher voltage value can prevent the problem of overcharging the battery. Similarly, when the battery pack is in a discharging state and the state of charge is less than or equal to the second preset power threshold, the smaller voltage value among the voltage values of the non-failed single cell batteries currently close to the failed single cell battery can be selected as the target voltage value of the failed single cell battery. Or, the average value of the voltages of the non-failed single cell batteries can be calculated and subtracted with a preset voltage value as the target voltage value of the failed single cell battery. Or, the minimum voltage value among the non-failed single cell batteries can be directly used as the target voltage value of the failed single cell battery. It should be noted that at the end of discharging, the battery voltage should be close to its minimum safe voltage, and using a smaller voltage value can prevent the problem of over-discharging the battery.

[0036] Thus, even in the case of partial single cell battery failure, it is possible to ensure that the battery pack can operate safely and effectively in different working states, which helps to protect the battery pack and thus extend the service life of the battery.

[0037] According to an embodiment of the present application, determining the target voltage value of a failed single battery based on the voltage values of the non-failed single batteries in the battery pack includes: when the battery pack is in a charging state and the state of charge is greater than or equal to a first preset charge threshold, using the maximum voltage value of the non-failed single batteries in the battery pack as the target voltage value of the failed single battery; when the battery pack is in a discharging state and the state of charge is less than or equal to a second preset charge threshold, using the minimum voltage value of the non-failed single batteries in the battery pack as the target voltage value of the failed single battery. For example, the first preset charge threshold can be 95% (assuming the full charge of the battery pack is 100%, accounting for 95% of the full charge), and the second preset charge threshold can be 5% (assuming the full charge of the battery pack is 100%, accounting for 5% of the full charge).

[0038] Specifically, when determining the target voltage value of a failed single battery based on the voltage values of the non-failed single batteries in the battery pack, the charge and discharge state and the state of charge of the battery pack are judged. When the battery pack is in a charging state and the state of charge is greater than or equal to a first preset charge threshold, the maximum voltage value of the non-failed single batteries in the battery pack can be used as the target voltage value of the failed single battery. The first preset charge threshold can be set according to the chemical characteristics, safety requirements and actual usage of the battery, and is used to identify the end of charging. For example, it is provided by the battery manufacturer or determined through experiments and tests. The first preset charge threshold is usually set at a safe point before the full charge state of the battery to avoid overcharging. Thus, when the battery pack is in a charging state and its state of charge reaches or exceeds the first preset charge threshold, it indicates that the battery pack is at the end of charging. In this case, to avoid overcharging, the maximum voltage value of the non-failed single batteries is used as the target voltage value of the failed single battery. This is because at the end of charging, the battery voltage should approach its maximum safe voltage, and using the maximum voltage value can ensure that the voltage of the failed single battery does not exceed this safety limit.

[0039] When the battery pack is in a discharging state and the state of charge is less than or equal to the second preset state-of-charge threshold, the minimum voltage value of the non-failed single cells in the battery pack can be used as the target voltage value of the failed single cell. The second preset state-of-charge threshold can be set according to the chemical characteristics, safety requirements and actual usage of the battery, and is used to identify the end of discharge. For example, it can be provided by the battery manufacturer or determined through experiments and tests, and can be set as a small safety margin after the battery is discharged to avoid over-discharge. Thus, when the battery pack is in a discharging state and its state of charge reaches or is lower than the second preset state-of-charge threshold, it indicates that the battery pack is at the end of discharge. In this case, to avoid over-discharge, the minimum voltage value among the non-failed single cells is used as the target voltage value of the failed single cell. This is because at the end of discharge, the battery voltage should be close to its minimum safety voltage, and using the minimum voltage value can ensure that the voltage of the failed single cell does not fall below this safety limit.

[0040] Therefore, the method of dynamically adjusting the target voltage value of the failed single cell based on the actual state of charge of the battery pack and the voltage values of the non-failed single cells can effectively protect the battery pack, prevent overcharge or over-discharge caused by the failure of a single cell, thereby extending the service life of the battery. Moreover, by using the voltage values of the non-failed single cells to estimate the target voltage value of the failed single cell, the voltage balance of the battery pack can be maintained, the overall performance and reliability of the battery pack can be improved, and it can ensure that the battery pack can operate safely and effectively under different working conditions.

[0041] According to an embodiment of the present application, the voltage estimation method of the failed single cell further includes: when the battery pack is in a charging state and the state of charge is less than the first preset state-of-charge threshold, or when the battery pack is in a discharging state and the state of charge is greater than the second preset state-of-charge threshold, or when the battery pack is in a non-charging state or a non-discharging state, determining the target voltage value of the failed single cell based on the single cell voltage values of the battery pack in the previous acquisition cycle.

[0042] Specifically, when the battery pack is in a charging state and the state of charge is less than the first preset power threshold, or when the battery pack is in a discharging state and the state of charge is greater than the second preset power threshold, that is, when the current battery pack is not at the end of charge or discharge, there is no need to consider the problem of overcharging or over-discharging. Therefore, the target voltage value of the failed single cell can be determined based on the voltage value of the failed single cell and the single cell voltage values of the battery pack in the previous acquisition cycle. That is to say, when the battery pack is in a charging state and its state of charge is less than the first preset power threshold (such as 95%), this means that the battery pack is not fully charged, or when the battery pack is in a discharging state and its state of charge is greater than the second preset power threshold (such as 5%), using the single cell voltage value of the previous acquisition cycle to determine the target voltage value of the failed single cell can provide a reference point to estimate the current battery state. In addition, when the battery pack is in a non-charging and non-discharging state, the voltage change of the battery pack is relatively small, but the continuity of voltage data and the integrity of fault diagnosis are still very important. Similarly, by determining the target voltage value of the failed single cell based on the single cell voltage values of the battery pack in the previous acquisition cycle, the continuity of voltage data can be ensured, misjudgment caused by a single invalid value can be avoided, and the stability and reliability of the system can be improved. This method is simple and efficient and is applicable to voltage estimation and fault diagnosis of the battery pack in a stationary state. For example, the single cell voltage values in the previous acquisition cycle can be obtained, and the single cell voltage value of the failed single cell in the previous cycle can be used as the voltage value of the failed single cell this time, or the single cell voltage value of the single cell whose position is relatively close to the position of the failed single cell in the previous cycle can also be used as the voltage value of the failed single cell this time.

[0043] Thereby, the continuity of voltage acquisition data can be ensured, the voltage value of the failed single cell can be effectively estimated, even if the failed single cell itself cannot provide a direct voltage reading, which helps to maintain the balance and safe operation of the battery pack.

[0044] Further, according to an embodiment of the present application, determining the target voltage value of the failed single cell based on the single cell voltage values of the battery pack in the previous acquisition cycle includes: respectively obtaining the voltage differences between the voltage value of the failed single cell in the previous acquisition cycle and the voltage values of each single cell other than the failed single cell in the previous acquisition cycle; taking the single cells in the previous acquisition cycle corresponding to the voltage differences less than the preset voltage threshold as the reference single cell set; obtaining the minimum distance between the positions of each reference single cell in the reference single cell set and the position of the failed single cell; taking the voltage value of the reference single cell corresponding to the minimum distance as the target voltage value of the failed single cell. Among them, the preset voltage threshold can be determined according to the actual situation.

[0045] Specifically, the voltage of the battery varies with time and usage conditions (such as temperature, current, etc.). By obtaining the individual cell voltage values in the previous acquisition cycle and directly using the individual cell voltage value of the failed individual cell in the previous cycle as the voltage value of the failed individual cell in this time, there is a situation where the voltage value of this individual cell changes compared to the previous time. This method will have a certain error compared to the actual situation. Therefore, when determining the target voltage value of the failed individual cell based on the individual cell voltage values of the battery pack in the previous acquisition cycle, in order to more accurately determine the target voltage value of the failed individual cell, the voltage differences between the voltage value of the failed individual cell in the previous acquisition cycle and the voltage values of each individual cell other than the failed individual cell in the previous acquisition cycle can be obtained respectively.

[0046] After obtaining the voltage differences, these voltage differences can be compared with a preset voltage threshold. The individual cells in the previous acquisition cycle corresponding to the voltage differences less than the preset voltage threshold are used as the reference individual cell set. Among them, the preset voltage difference can be 2V. That is to say, these individual cells are considered to be the closest to the voltage value of the failed individual cell after the voltage change this time compared to the previous time and can be selected as the reference individual cell set. This set contains the normal individual cells closest to the voltage of the failed individual cell. In the reference individual cell set, calculate the distance between the position of each reference individual cell and the position of the failed individual cell, and find the minimum distance. Here, the position refers to the physical position or electrical connection order of the individual cells in the battery pack, and the minimum distance can be determined according to the individual cell numbers. For example, the ones with the closest numbers can be regarded as the closest in distance. Finally, the voltage value of the reference individual cell corresponding to the minimum distance can be used as the target voltage value of the failed individual cell. That is to say, the voltage value of the individual cell closest to the position of the failed individual cell is selected as the estimated value.

[0047] For example, assume that a battery pack has 100 single cells, and the 50th single cell fails. Obtain the estimated voltage value of the 50th single cell in the previous acquisition cycle, and compare it with the voltage values of the other 99 single cells to determine the set of single cells with a voltage difference less than a preset threshold. Assume that this includes the 48th, 49th, 51st, and 52nd single cells. Calculate the distances between the 48th, 49th, 51st, and 52nd single cells and the 50th single cell, and find the minimum distance. Assume that the distances between the 49th and 51st single cells and the 50th single cell are the closest. Select the voltage value of the single cell corresponding to the minimum distance as the target voltage value of the 50th single cell. If the distances of the 49th and 51st single cells are the same, the voltage value of any one of them can be selected as the target voltage value of the 50th single cell. Thus, the voltage value of the failed single cell can be effectively estimated. Even if the failed single cell itself cannot provide a direct voltage reading, this estimation method helps to maintain the balance and safe operation of the battery pack, especially in the case of battery failure.

[0048] According to an embodiment of the present application, the method for estimating the voltage of a failed single cell further includes: when the battery pack is in a charging state and the state of charge is greater than or equal to a third preset state-of-charge threshold, controlling the battery pack to stop charging, where the third preset state-of-charge threshold is greater than the first preset state-of-charge threshold; when the battery pack is in a discharging state and the state of charge is less than or equal to a fourth preset state-of-charge threshold, controlling the battery pack to stop discharging, where the fourth preset state-of-charge threshold is less than the second preset state-of-charge threshold. Among them, the third preset state-of-charge threshold and the fourth preset state-of-charge threshold can be determined according to the actual situation.

[0049] Specifically, the charge-discharge state and state of charge of the battery pack are judged. When the battery pack is in the charging state and the state of charge is greater than or equal to the third preset power threshold, the charging of the battery pack can be controlled to stop. Among them, the third preset power threshold is greater than the first preset power threshold. That is to say, the third preset power threshold is a preset threshold higher than the first preset power threshold, which is used to identify the state that the battery charging is about to be completed. For example, the third preset power threshold can be 98%. When the state of charge reaches or exceeds the third preset power threshold, the charging of the battery will be controlled to end in advance. In addition, when the battery is close to full charge, if charging continues, it may cause the internal chemical reaction of the battery to be overly active, thus increasing the risk of battery overheating, swelling or even damage. And when the battery pack is in the charging state and the state of charge is greater than or equal to the first preset power threshold, when the maximum voltage value of the non-failed single cells in the battery pack is used as the target voltage value of the failed single cell, there may be a situation where after replacing the voltage value of the failed single cell with a larger voltage value, the current total voltage value is slightly larger. Therefore, by ending the charging in advance when the state of charge reaches the third preset power threshold, it can be ensured that the battery will not be in a high voltage state for a long time, thereby reducing battery aging and extending the battery life. In addition, from the perspective of safety, during the charging process of the battery, the voltage will gradually rise. When the voltage is close to the maximum safe voltage of the battery, even if the state of charge has not reached 100%, the charging needs to be stopped to protect the battery.

[0050] When the battery pack is in the discharging state and the state of charge is less than or equal to the fourth preset power threshold, the discharging of the battery pack can be controlled to stop. Among them, the fourth preset power threshold is less than the second preset power threshold. That is to say, a lower threshold, the second preset power threshold, is set to identify the end stage of discharging, and a lower fourth preset power threshold is set to actually stop discharging to ensure that the battery will not be discharged to a dangerous level. For example, the fourth preset power threshold can be 3%. That is, when the battery pack is in the discharging state and its state of charge reaches or is lower than the fourth preset power threshold, it indicates that the battery pack is close to the empty state, and the discharging of the battery pack can be controlled to stop. Thus, this method can effectively protect the battery pack, prevent overcharging or over-discharging caused by the failure of single cells, thereby extending the service life of the battery. And by using the preset power threshold to control charging and discharging, the voltage balance of the battery pack can be maintained, and the overall performance and reliability of the battery pack can be improved.

[0051] According to an embodiment of the present application, the voltage estimation method for failed single cells further includes: determining the fault type of the failed single cell based on the local outlier factor algorithm; determining the fault reporting and handling strategy based on the fault type.

[0052] Specifically, in the current related technologies, the number of invalid monomers collected by the battery sampling chip is identified, the fault diagnosis frequency is changed to improve the speed of fault identification, and whether a disconnection fault occurs is judged by diagnosing the number of disconnection faults, but the cause of the fault is not analyzed and a specific fault handling method is not adopted. The main reasons for the invalid values of the monomer voltage acquisition are mainly three situations: disconnection fault of the monomer voltage acquisition line, incorrect connection order of the monomer voltage acquisition line interface, and abnormal acquisition of the monomer voltage acquisition chip. Since the invalid value data distributions collected in these three situations have large differences, for example, 0V will appear when the acquisition line is broken, negative values may appear when the wiring order is connected incorrectly, and the invalid values may be continuous when the AFE fails.

[0053] Therefore, aiming at the characteristics of invalid value data collected for different faults, this application can determine the fault type of the failed monomer battery according to the local outlier factor algorithm, and after determining the fault type, the fault reporting and handling strategy can be determined according to the fault type. Among them, the Local Outlier Factor (LOF) algorithm is a machine learning method for identifying outliers in a dataset. The LOF algorithm determines whether a data point is an outlier by comparing the local density difference between each data point and its neighboring data points. That is, for each data point, the LOF algorithm calculates its LOF value, which reflects the local density difference between this point and its neighboring points. If a point has a high LOF value, it means that this point is more likely to be an outlier than its neighboring points. According to the characteristics of the collected invalid value data, an outlier probability distribution model suitable for different fault types is selected. For example, a disconnection of the acquisition line may generate an outlier of 0V, an incorrect wiring order may generate negative values, and an abnormal AFE acquisition chip may generate continuous invalid values. Statistical principles, such as comparing the actually measured voltage value and the monitored voltage value, are used to determine which outliers are caused by specific fault types. By analyzing the distribution characteristics of these outliers, different fault types can be identified. According to the LOF value and the selected probability distribution model, the most likely fault type that each outlier belongs to can be determined. For example, if the voltage value of a monomer battery is much lower than that of other batteries and conforms to the outlier distribution characteristics of the disconnection of the acquisition line, then it can be determined that the fault type is the disconnection of the acquisition line. Once the fault type is determined, the fault can be reported and processed according to the preset strategy. For example, for serious faults, such as disconnection or abnormal AFE acquisition chip, it may be necessary to immediately notify the maintenance personnel; while for relatively minor faults, it may only be necessary to record and monitor its development.

[0054] According to an embodiment of the present application, the fault types include open - circuit faults or faults where the harness sequence is reversed. Based on the fault types, a fault reporting and handling strategy is determined, including: in the case where the fault type is an open - circuit fault or a fault where the harness sequence is reversed, obtaining, within the single - power - on time, the first ratio of the number of single - cell battery failures in the battery pack to the total number of acquisitions; if the first ratio is greater than the first preset ratio, reporting the fault type and sending a maintenance reminder; if the first ratio is greater than or equal to the second preset ratio and less than or equal to the first preset ratio, storing and counting the current fault type, and when the count exceeds the first preset number of times, reporting the fault type and sending a maintenance reminder; if the first ratio is less than the second preset ratio, storing the current fault type. Among them, the first preset ratio, the second preset ratio, and the first preset number of times can be determined according to the actual situation. For example, the first preset ratio can be 5%, the second preset ratio can be 3%, and the first preset number of times is 3 times.

[0055] Specifically, the fault types may include open - circuit faults or faults where the harness sequence is reversed. When determining the fault reporting and handling strategy based on the fault types, in the case where the fault type is an open - circuit fault or a fault where the harness sequence is reversed, the first ratio of the number of single - cell battery failures in the battery pack to the total number of acquisitions can be obtained within the single - power - on time. For example, during each power - on (start - up) of the battery pack, the number of single - cell battery failures is counted, and this number is divided by the total number of acquisitions to obtain the first ratio (i.e., the failure rate). The size relationship between the first ratio and the first preset ratio is judged. When the first ratio is greater than the first preset ratio, it indicates that the fault occurrence frequency is too high, which may affect the safety and performance of the battery pack. Thus, the fault type can be directly reported and a maintenance reminder can be sent to the vehicle owner or maintenance personnel.

[0056] The size relationship between the first ratio and the first preset ratio and the second preset ratio is judged. When the first ratio is greater than or equal to the second preset ratio and less than or equal to the first preset ratio, the current fault type can be stored and counted. If the cumulative number of times exceeds the first preset number of times, then the fault type is reported and a maintenance reminder is sent. This method allows the system to monitor the fault occurrence frequency, avoid immediately triggering maintenance due to accidental faults, and at the same time take action when the faults occur frequently, reporting the fault type and sending a maintenance reminder to the vehicle owner or maintenance personnel. When the first ratio is less than the second preset ratio, it indicates that the current fault occurrence frequency is very low and is not sufficient to cause immediate attention, so the current fault type can be stored. This ensures that a complete voltage fault record can be provided in all cases, meets the compliance or safety consideration standards, and can be used for long - term fault analysis and trend monitoring.

[0057] For example, during a power-on cycle, fault collection is performed multiple times, such as 100 times, to ensure real-time monitoring of the battery status and timely detection of abnormalities. If the number of single-cell failures in the battery pack exceeds 5 times, and if single-cell failures occur 10 times during the current voltage acquisition process, the first ratio can be determined to be 10% (10 / 100). Since the first ratio (10%) is greater than the first preset ratio (5%), it can be determined that the fault occurrence frequency is too high, which may affect the safety and performance of the battery pack. Thus, the fault type can be directly reported, and a maintenance reminder can be sent to the vehicle owner or maintenance personnel. If single-cell failures occur 4 times during the current voltage acquisition process, the first ratio can be determined to be 4% (4 / 100). Since the first ratio (4%) is greater than the second preset ratio (3%) and less than the first preset ratio (5%), the current fault type can be stored and counted, and it can be determined whether the current count exceeds the first preset number (such as 3 times). If the current cumulative count exceeds 3 times, the fault type can be reported, and a maintenance reminder can be sent to the vehicle owner or maintenance personnel. If the current cumulative count does not exceed 3 times, and if the current cumulative count is 2 times, the battery status can continue to be monitored. If the first ratio is still between the first preset ratio and the second preset ratio during the next power-on, counting can continue until the cumulative count exceeds 3 times, at which point the fault type is reported and a maintenance reminder is sent to the vehicle owner or maintenance personnel. If single-cell failure occurs 1 time during the current voltage acquisition process, the first ratio can be determined to be 1% (1 / 100). Since the first ratio (1%) is less than the second preset ratio (3%), the current fault type can be stored. That is, for compliance or safety reasons, a complete operation record can be ensured in all cases and can be used for long-term fault analysis and trend monitoring. That is, the long-term accumulated data can still reflect potential problems.

[0058] Thus, it is possible to reasonably allocate maintenance resources according to the frequency and severity of fault occurrences, while reducing false alarms and missed reports, and improving the reliability and safety of the battery pack.

[0059] According to an embodiment of the present application, the fault type includes AFE acquisition faults. Based on the fault type, a fault reporting and handling strategy is determined, including: when the fault type is an AFE acquisition fault and the fault acquisition rate of the AFE chip is greater than or equal to the preset chip failure rate, obtaining the second ratio of the number of single-cell failures in the battery pack to the total number of acquisitions during a single power-on time; if the second ratio is greater than the third preset ratio, reporting the fault type and sending a maintenance reminder; if the second ratio is greater than the fourth preset ratio and less than the third preset ratio, storing and counting the current fault type, and when the count exceeds the second preset number, reporting the fault type and sending a maintenance reminder; if the second ratio is less than the fourth preset ratio, storing the current fault type. Among them, the third preset ratio, the fourth preset ratio, and the second preset number can be determined according to the actual situation.

[0060] Specifically, the fault types may include AFE acquisition faults. When determining the fault reporting and handling strategy based on the fault type, if the fault type is an AFE acquisition fault and the fault acquisition rate of the AFE chip is greater than or equal to the preset chip failure rate, the second ratio of the number of single-cell failures in the battery pack to the total number of acquisitions during a single power-on time can be obtained. For example, the preset chip failure rate can be determined according to the chip characteristics. For instance, the preset chip failure rate is 1 pmm. That is to say, when the AFE acquisition fault is less than this preset chip failure rate, no reporting or counting is performed, which belongs to the normal failure rate range of the chip. In this case, these faults are considered random and occasional and will not have a significant impact on the system performance. Therefore, no measures need to be taken. When the AFE acquisition fault is greater than or equal to this preset chip failure rate, it indicates that the fault frequency of the AFE chip is relatively high and may affect the normal operation of the system. Thus, during each power-on (start-up) of the battery pack, the number of single-cell failures is counted, and this number is divided by the total number of acquisitions to obtain the second ratio (i.e., the ratio of the number of failures). The magnitude relationship between the second ratio and the third preset ratio is judged. If the second ratio is greater than the third preset ratio, it means that the fault occurrence frequency is too high and may affect the safety and performance of the battery pack. Consequently, the fault type can be directly reported, and a maintenance reminder can be sent to the vehicle owner or maintenance personnel.

[0061] The magnitude relationship between the second ratio, the third preset ratio, and the fourth preset ratio is judged. If the second ratio is greater than or equal to the fourth preset ratio and less than or equal to the third preset ratio, the current fault type can be stored and counted. If the cumulative number of times exceeds the second preset number of times, the fault type is reported, and a maintenance reminder is sent. This method allows the system to monitor the fault occurrence frequency, avoid immediately triggering maintenance due to occasional faults, and take actions when faults occur frequently, reporting the fault type and sending a maintenance reminder to the vehicle owner or maintenance personnel. When the second ratio is less than the fourth preset ratio, it means that the current fault occurrence frequency is very low and is not sufficient to attract immediate attention. The current fault type can be stored, which ensures that a complete voltage fault record can be provided in all cases, meets the compliance or safety consideration standards, and can be used for long-term fault analysis and trend monitoring.

[0062] For example, during a power-on cycle, the AFE chip performs fault collection multiple times, such as 100 times, to ensure real-time monitoring of the battery status and timely detection of abnormalities. If the situation of single-cell battery failure occurs 8 times during the current voltage acquisition process, the second ratio can be determined as 8% (8 / 100). Since the second ratio (8%) is greater than the third preset ratio (6%), it can be determined that the fault occurrence frequency is too high, which may affect the safety and performance of the battery pack. Thus, the fault type can be directly reported, and a maintenance reminder can be sent to the vehicle owner or maintenance personnel. If the situation of single-cell battery failure occurs 5 times during the current voltage acquisition process, the second ratio can be determined as 5% (5 / 100). Since the second ratio (5%) is greater than the fourth preset ratio (3%) and less than the third preset ratio (6%), the current fault type can be stored and counted, and it is determined whether the current count exceeds the second preset number (such as 3 times). If the current cumulative count exceeds 3 times, the fault type can be reported, and a maintenance reminder can be sent to the vehicle owner or maintenance personnel. If the current cumulative count does not exceed 3 times, and if the current cumulative count is 1 time, the battery status can continue to be monitored. If the first ratio is still between the first preset ratio and the second preset ratio during the next power-on, the count can continue until the cumulative count exceeds 3 times, at which point the fault type is reported and a maintenance reminder is sent to the vehicle owner or maintenance personnel. If the situation of single-cell battery failure occurs 2 times during the current voltage acquisition process, the second ratio can be determined as 2% (2 / 100). Since the second ratio (2%) is less than the fourth preset ratio (3%), the current fault type can be stored. That is, for compliance or safety considerations, a complete operation record can be provided in all cases and can be used for long-term fault analysis and trend monitoring. That is, the data accumulated over a long period can still reflect potential problems.

[0063] Thus, it is possible to reasonably allocate maintenance resources according to the frequency and severity of fault occurrence, while reducing false alarms and missed alarms, and improving the reliability and safety of the battery pack.

[0064] According to an embodiment of the present application, the voltage estimation method for a failed single-cell battery further includes: obtaining the voltage value of each single-cell battery in the battery pack during the current acquisition cycle; and determining the corresponding single-cell battery as a failed single-cell battery when the voltage value of the single-cell battery is less than or equal to a preset voltage threshold. The preset voltage threshold can be determined according to the actual situation.

[0065] Specifically, the voltage values of each single battery in the battery pack during the current acquisition cycle are obtained. For example, in a battery management system, the voltage values of each single battery in the battery pack can be obtained based on an AFE chip to monitor the battery status in real time. The magnitude relationship between the voltage value of each single battery collected and a preset voltage threshold is judged. When the voltage value of a single battery is less than or equal to the preset voltage threshold, it can be considered that the single battery has failed or its performance has declined, and the corresponding single battery can be determined as a failed single battery. Among them, the preset voltage threshold is set based on the chemical characteristics and safe operating range of the battery. For example, for a lithium-ion battery, the preset voltage threshold can be 2V or lower.

[0066] The following describes the estimation method of the present application in conjunction with Figure 2 to describe the estimation method of this application.

[0067] As a specific example, the voltage estimation method for the failed single battery of the present application may include the following steps:

[0068] S101, obtain the voltage values of each single battery in the battery pack during the current acquisition cycle.

[0069] S102, when the voltage value of a single battery is less than or equal to the preset voltage threshold, determine the corresponding single battery as a failed single battery and determine the number of failed single batteries.

[0070] S103, determine the number of failed single batteries in the battery pack.

[0071] S104, judge whether the number of failed single batteries is less than or equal to a preset threshold. If so, execute step S105; if not, execute step S115.

[0072] S105, obtain the charge-discharge state and state of charge of the battery pack.

[0073] S106, judge whether the battery pack is in a charging state. If so, execute step S107; if not, execute step S112.

[0074] S107, judge whether the state of charge is greater than or equal to a first preset state-of-charge threshold. If so, execute step S108; if not, execute step S109.

[0075] S108, use the maximum voltage value of the non-failed single batteries in the battery pack as the target voltage value of the failed single battery and stop charging when the state of charge is greater than or equal to a third preset state-of-charge threshold.

[0076] S109, obtain the voltage difference between the voltage value of the failed single battery in the previous acquisition cycle and the voltage values of each single battery other than the failed single battery in the previous acquisition cycle.

[0077] S110, use the single cells in the previous acquisition period whose voltage difference is less than the preset voltage threshold as the reference single cell set.

[0078] S111, obtain the minimum distance between the position of each reference single cell in the reference single cell set and the position of the failed single cell, and use the voltage value of the reference single cell corresponding to the minimum distance as the target voltage value of the failed single cell.

[0079] S112, determine whether the battery pack is in a discharging state. If yes, execute step S113; if no, execute step S105.

[0080] S113, determine whether the state of charge is less than or equal to the second preset state-of-charge threshold. If yes, execute step S114; if no, execute step S109.

[0081] S114, use the minimum voltage value of the non-failed single cells in the battery pack as the target voltage value of the failed single cell, and stop discharging when the state of charge is less than or equal to the fourth preset state-of-charge threshold.

[0082] S115, stop charging and discharging.

[0083] In summary, according to the voltage estimation method of the failed single cell in the embodiment of the present application, the number of failed single cells in the battery pack is determined. When the number of failed single cells is less than or equal to the preset threshold, the charge and discharge state and the state of charge of the battery pack are obtained. When the battery pack is in a charging state and the state of charge is greater than or equal to the first preset state-of-charge threshold, or when the battery pack is in a discharging state and the state of charge is less than or equal to the second preset state-of-charge threshold, the target voltage value of the failed single cell is determined based on the voltage values of the non-failed single cells in the battery pack. Thus, this method can effectively avoid voltage acquisition failures caused by problems in the voltage acquisition hardware in practical applications, reduce the impact of abnormal voltage acquisition values, and avoid overcharging and over-discharging problems of the battery, improving driving safety.

[0084] Corresponding to the above embodiment, the present application also proposes a vehicle.

[0085] As Figure 3 shown, the vehicle 200 in the embodiment of the present application may include: a memory 210, a processor 220, and a program stored on the memory 210 and executable on the processor 220. When the processor 220 executes the program, the above-mentioned voltage estimation method of the failed single cell is implemented.

[0086] According to the vehicle of the embodiment of the present application, by implementing the above voltage estimation method for the failed single cell, it is possible to effectively avoid voltage acquisition failures caused by problems in the voltage acquisition hardware in practical applications, reduce the impact of abnormal voltage acquisition values, and avoid overcharging and over-discharging problems of the battery, thereby improving driving safety.

[0087] Corresponding to the above embodiment, the present application also proposes a voltage estimation device for a failed single cell.

[0088] As Figure 4 shown, the voltage estimation device 100 for a failed single cell according to the embodiment of the present application includes: a determination module 110, an acquisition module 120, and an estimation module 130.

[0089] Among them, the determination module 110 is used to determine the number of failed single cells in the battery pack. The acquisition module 120 is used to acquire the charge and discharge state and the state of charge of the battery pack when the number of failed single cells is less than or equal to a preset threshold. The estimation module 130 is used to determine the target voltage value of the failed single cell based on the voltage values of the non-failed single cells in the battery pack when the battery pack is in a charging state and the state of charge is greater than or equal to a first preset state-of-charge threshold, or when the battery pack is in a discharging state and the state of charge is less than or equal to a second preset state-of-charge threshold.

[0090] According to an embodiment of the present application, the determination module 110 determines the target voltage value of the failed single cell based on the voltage values of the non-failed single cells in the battery pack, specifically: when the battery pack is in a charging state and the state of charge is greater than or equal to a first preset state-of-charge threshold, taking the maximum voltage value of the non-failed single cells in the battery pack as the target voltage value of the failed single cell; when the battery pack is in a discharging state and the state of charge is less than or equal to a second preset state-of-charge threshold, taking the minimum voltage value of the non-failed single cells in the battery pack as the target voltage value of the failed single cell.

[0091] According to an embodiment of the present application, the estimation module 130 is further used to: when the battery pack is in a charging state and the state of charge is less than the first preset state-of-charge threshold, or when the battery pack is in a discharging state and the state of charge is greater than the second preset state-of-charge threshold, or when the battery pack is in a non-charging state or a non-discharging state, determine the target voltage value of the failed single cell based on the single cell voltage values of the battery pack in the previous acquisition cycle.

[0092] According to an embodiment of the present application, the estimation module 130 determines the target voltage value of the failed single cell based on the voltage values of the single cells in the battery pack in the previous acquisition cycle. Specifically, it is used to: respectively obtain the voltage differences between the voltage value of the failed single cell in the previous acquisition cycle and the voltage values of each single cell other than the failed single cell in the previous acquisition cycle; take the single cells within the previous acquisition cycle corresponding to the voltage differences less than the preset voltage threshold as the reference single cell set; obtain the minimum distance between the positions of each reference single cell in the reference single cell set and the position of the failed single cell; take the voltage value of the reference single cell corresponding to the minimum distance as the target voltage value of the failed single cell.

[0093] According to an embodiment of the present application, the estimation module 130 is further used to: when the battery pack is in a charging state and the state of charge is greater than or equal to the third preset state-of-charge threshold, control the battery pack to stop charging, where the third preset state-of-charge threshold is greater than the first preset state-of-charge threshold; when the battery pack is in a discharging state and the state of charge is less than or equal to the fourth preset state-of-charge threshold, control the battery pack to stop discharging, where the fourth preset state-of-charge threshold is less than the second preset state-of-charge threshold.

[0094] According to an embodiment of the present application, the estimation module 130 is further used to: determine the fault type of the failed single cell based on the local outlier factor algorithm; determine the fault reporting and handling strategy based on the fault type.

[0095] According to an embodiment of the present application, the fault type includes a disconnection fault or a harness sequence reverse connection fault. The estimation module 130 determines the fault reporting and handling strategy based on the fault type. Specifically, it is used to: when the fault type is a disconnection fault or a harness sequence reverse connection fault, obtain the first ratio of the number of single cell failures in the battery pack to the total number of acquisitions within a single power-on time; if the first ratio is greater than the first preset ratio, report the fault type and issue a maintenance reminder; if the first ratio is greater than the second preset ratio and less than the first preset ratio, store and count the current fault type, and when the count exceeds the first preset number, report the fault type and issue a maintenance reminder; if the first ratio is less than the second preset ratio, store the current fault type.

[0096] According to an embodiment of the present application, the fault type includes AFE acquisition fault. The estimation module 130 determines a fault reporting and handling strategy based on the fault type, specifically used for: when the fault type is AFE acquisition fault and the fault acquisition rate of the AFE chip is greater than or equal to the preset chip failure rate, obtaining the second ratio of the number of single-cell failures in the battery pack to the total acquisition times within a single power-on time; if the second ratio is greater than the third preset ratio, reporting the fault type and sending a maintenance reminder; if the second ratio is greater than the fourth preset ratio and less than the third preset ratio, storing and counting the current fault type, and when the count exceeds the second preset number, reporting the fault type and sending a maintenance reminder; if the second ratio is less than the fourth preset ratio, storing the current fault type.

[0097] It should be noted that for the details not disclosed in the voltage estimation device for failed single cells in the embodiments of the present application, please refer to the details disclosed in the voltage estimation method for failed single cells in the embodiments of the present application, and will not be elaborated here specifically.

[0098] According to the voltage estimation device for failed single cells in the embodiments of the present application, the determination module is used to determine the number of failed single cells in the battery pack. The acquisition module is used to obtain the charge and discharge state and state of charge of the battery pack when the number of failed single cells is less than or equal to the preset threshold. The estimation module is used to determine the target voltage value of the failed single cell based on the voltage values of the non-failed single cells in the battery pack when the battery pack is in a charging state and the state of charge is greater than or equal to the first preset power threshold, or when the battery pack is in a discharging state and the state of charge is less than or equal to the second preset power threshold. Thus, the device can effectively avoid voltage acquisition faults caused by problems in voltage acquisition hardware in practical applications, reduce the impact of abnormal voltage acquisition values, and avoid overcharging and over-discharging problems of the battery, improving driving safety.

[0099] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a definite sequence list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or in combination with these instruction execution systems, apparatus, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection portion with one or more wirings (electronic device), a portable computer diskette case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or other suitable processing as necessary, and then stored in a computer memory.

[0100] It should be understood that various parts of the present application can be implemented by hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application-specific integrated circuits having suitable combinational logic gate circuits, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), and the like.

[0101] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0102] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of this application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0103] In this application, unless otherwise clearly stipulated and defined, terms such as "installed", "connected", "linked", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0104] Although the embodiments of this application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting this application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A method for estimating the voltage of a failed single cell, characterized in that: The method comprises: Determine the number of failed cells in the battery pack; When the number of the failed single cells is less than or equal to a preset threshold, obtaining a charge / discharge state and a charge state of the battery pack; When the battery pack is in a charging state and the state of charge is greater than or equal to a first preset power threshold, or when the battery pack is in a discharging state and the state of charge is less than or equal to a second preset power threshold, a target voltage value of the failed single cell is determined based on the voltage value of a non-failed single cell in the battery pack.

2. The method for estimating the voltage of a failed single cell according to claim 1, characterized in that: Determining a target voltage value of the failed single cell based on the voltage value of the non-failed single cell in the battery pack includes: When the battery pack is in a charging state and the state of charge is greater than or equal to a first preset power threshold, taking the maximum voltage value of the non-failed single cells in the battery pack as the target voltage value of the failed single cell; When the battery pack is in a discharging state and the state of charge is less than or equal to a second preset power threshold, the minimum voltage value of the non-failed single cells in the battery pack is used as the target voltage value of the failed single cell.

3. The method for estimating the voltage of a failed single cell according to claim 1, characterized in that: The method further comprises: When the battery pack is in a charging state and the charge state is less than a first preset power threshold, or when the battery pack is in a discharging state and the charge state is greater than the second preset power threshold, or when the battery pack is in a non-charging state or a non-discharging state, the target voltage value of the failed single cell is determined based on the single cell voltage value of the battery pack in the previous acquisition cycle.

4. The method for estimating the voltage of a failed single cell according to claim 3, characterized in that: Determining the target voltage value of the failed single cell based on the single cell voltage value of the battery pack in the previous acquisition cycle includes: Respectively obtaining a voltage difference between a voltage value of the failed single cell in a previous acquisition cycle and a voltage value of each single cell except the failed single cell in the previous acquisition cycle; Taking the single cells in the previous acquisition cycle whose voltage difference is less than the preset voltage threshold as a reference single cell set; Obtaining a minimum distance between a position of each reference single cell in the reference single cell set and a position of the failed single cell; The voltage value of the reference single cell corresponding to the minimum distance value is used as the target voltage value of the failed single cell.

5. The method for estimating the voltage of a failed single cell according to claim 2, characterized in that: The method further comprises: When the battery pack is in a charging state and the state of charge is greater than or equal to a third preset power threshold, controlling the battery pack to stop charging, wherein the third preset power threshold is greater than the first preset power threshold; When the battery pack is in a discharging state and the state of charge is less than or equal to a fourth preset power threshold, the battery pack is controlled to stop discharging, wherein the fourth preset power threshold is less than the second preset power threshold.

6. The method for estimating the voltage of a failed single cell according to any one of claims 1 to 5, characterized in that: The method further comprises: Determine the fault type of the failed single cell based on the local outlier factor algorithm; A fault reporting and handling strategy is determined based on the fault type.

7. The method for estimating the voltage of a failed single cell according to claim 6, characterized in that: The fault type includes a disconnection fault or a wiring harness sequence reverse connection fault, and the fault reporting and handling strategy determined based on the fault type includes: When the fault type is the disconnection fault or the reverse connection fault of the wiring harness sequence, obtaining a first ratio of the number of single cell failures in the battery pack to the total number of acquisitions within a single power-on time; If the first ratio is greater than a first preset ratio, the fault type is reported and a maintenance reminder is issued; If the first ratio is greater than or equal to the second preset ratio and less than or equal to the first preset ratio, the fault type is stored and counted, and when the count exceeds the first preset number, the fault type is reported and a maintenance reminder is issued; If the first ratio is smaller than the second preset ratio, the current fault type is stored.

8. The method for estimating voltage of a failed single cell according to claim 6, characterized in that: The fault type includes an AFE acquisition fault, and the determining of a fault reporting and processing strategy based on the fault type includes: When the fault type is the AFE acquisition fault and the fault acquisition rate of the AFE chip is greater than or equal to the preset chip failure rate, obtaining a second ratio of the number of single cell failures in the battery pack to the total number of acquisitions within a single power-on time; If the second ratio is greater than the third preset ratio, the fault type is reported and a maintenance reminder is issued; If the second ratio is greater than or equal to the fourth preset ratio and less than or equal to the third preset ratio, the fault type is stored and counted, and when the count exceeds the second preset number, the fault type is reported and a maintenance reminder is issued; If the second ratio is smaller than the fourth preset ratio, the current fault type is stored.

9. A vehicle, characterized in that: include: A memory, a processor, and a program stored in the memory and executable on the processor, wherein when the processor executes the program, the method for estimating the voltage of a failed single cell according to any one of claims 1 to 8 is implemented.

10. A device for estimating voltage of a failed single cell, characterized in that: The device comprises: A determination module, used to determine the number of failed single cells in the battery pack; An acquisition module, used for acquiring a charge / discharge state and a charge state of a battery pack when the number of the failed single cells is less than or equal to a preset threshold; An estimation module is used to determine a target voltage value of the failed single cell based on the voltage value of a non-failed single cell in the battery pack when the battery pack is in a charging state and the charge state is greater than or equal to a first preset charge threshold, or when the battery pack is in a discharging state and the charge state is less than or equal to a second preset charge threshold.

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