Battery system open circuit diagnosis method and device based on power detection, and electronic equipment

Abstract

The invention discloses a battery system open circuit diagnosis method and device based on power detection and electronic equipment, and relates to the field of battery fault diagnosis or other related technical fields, and the method comprises the steps: reading the initial accumulated power of each battery branch in a multi-branch battery system of a target vehicle at an initial moment; under the condition that a preset condition is met, reading first accumulated power of each battery branch in the multi-branch battery system at a target moment; calculating a power difference value and a power difference threshold value of each battery branch; comparing the power difference value of each battery branch circuit with a power difference threshold value to obtain a power difference value comparison result, and determining whether a candidate battery branch circuit with an open circuit exists or not; and verifying the open circuit condition of the candidate battery branch, and generating an open circuit diagnosis result of the multi-branch battery system based on a verification result. According to the invention, the technical problem of low accuracy of the judgment result of judging the open circuit condition of the battery branch through the current value in the related technology is solved.

Description

Technical Field

[0001] The present invention relates to the field of battery fault diagnosis or other related technical fields, and in particular to a method and device for diagnosing a battery system short circuit based on power detection, and electronic equipment. Background Art

[0002] With the development of battery technology in applications such as electric vehicles, hybrid vehicles, and energy storage systems, multi-branch battery systems are becoming more and more common due to their higher energy density, better thermal management, and more flexible configuration. However, accurate diagnosis of branch circuit breaks in these systems is critical to ensure the safe and efficient operation of the battery system.

[0003] In the related technology, the detection of branch circuit breakage is carried out by the high-voltage interlocking method of the high-voltage connector. This method is extremely dependent on the performance of the connector. The operation of the whole vehicle under different working conditions may cause the connector to loosen, or the connector may be damaged after multiple plugging and unplugging, which will affect the accuracy of branch circuit breakage detection. The second is to detect the current value flowing through each branch, and infer whether each branch has a circuit break by judging the current size. This can effectively avoid misjudgment caused by the performance of the high-voltage connector, but due to the differences in the battery cells of each branch, at the end of charging, a circulating current phenomenon may occur, that is, a branch has a large current, while the current flowing through individual branches is extremely small. There is a risk of false alarms, resulting in low accuracy of the detection results. If a branch falsely reports a circuit break, the vehicle will be unable to go on high voltage, affecting the user experience and even driving safety.

[0004] To address the above-mentioned problems, no effective solution has been proposed yet. Summary of the invention

[0005] The embodiments of the present invention provide a method and device for diagnosing a battery system short circuit based on power detection, and an electronic device, so as to at least solve the technical problem in the related art that the accuracy of the judgment result is low in judging the short circuit condition of a battery branch by current value.

[0006] According to one aspect of an embodiment of the present invention, a method for diagnosing a battery system open circuit based on power detection is provided, comprising: after detecting that a target vehicle performs a high-voltage operation, reading the initial cumulative power of each battery branch in a multi-branch battery system of the target vehicle at an initial moment; if the multi-branch battery system meets a preset condition within a target time period, reading the first cumulative power of each battery branch in the multi-branch battery system at a target moment, wherein the target moment is later than the initial moment; calculating a power difference based on the initial cumulative power and the first cumulative power, and calculating a power difference threshold of each of the battery branches; comparing the power difference of each of the battery branches with the power difference threshold to obtain a power difference comparison result, and determining whether there is a candidate battery branch with an open circuit based on the power difference comparison result; if there is a candidate battery branch with an open circuit in the multi-branch battery system, verifying the open circuit condition of the candidate battery branch to obtain a verification result, and generating a circuit open diagnosis result of the multi-branch battery system based on the verification result.

[0007] Optionally, the step of verifying the short circuit condition of the candidate battery branch to obtain the verification result includes: counting the cumulative power of each battery branch at each moment in a preset time period, wherein the duration of the preset time period is greater than the duration of the target time period; sorting the cumulative power of each battery branch at each moment to obtain a sorting result; and verifying the short circuit condition of the candidate battery branch based on the sorting result at each moment to obtain a verification result.

[0008] Optionally, the step of verifying the open circuit condition of the candidate battery branch based on the sorting result at each moment to obtain the verification result includes: extracting the maximum and minimum cumulative power values ​​at each moment from the sorting result at each moment, and calculating the difference between the maximum and minimum cumulative power values ​​at each moment to obtain the maximum power difference at each moment; obtaining a preset maximum power difference threshold, and verifying the open circuit condition of the candidate battery branch based on the maximum power difference at each moment and the preset maximum power difference threshold to obtain the verification result.

[0009] Optionally, a preset maximum power difference threshold is obtained, and the open circuit condition of the candidate battery branch is verified based on the maximum power difference value at each moment and the preset maximum power difference threshold, to obtain the step of obtaining the verification result, including: comparing the maximum power difference value at each moment with the maximum power difference threshold to obtain the maximum power difference comparison result at each moment; counting the maximum power difference comparison results at all moments within a preset time period, and generating a verification result based on the maximum power difference comparison results at all moments within the preset time period, wherein, when the maximum power difference comparison results at all moments within the preset time period indicate that the maximum power difference value is greater than the maximum power difference threshold, it is determined that the candidate battery branch is open circuit, and the open circuit verification result is obtained.

[0010] Optionally, before reading the first accumulated power of each battery branch in the multi-branch battery system at the target time, it also includes: collecting the total current of the battery branches of the multi-branch battery system within the target time period; collecting the single cell voltage of each battery branch of the multi-branch battery system within the target time period; comparing the total current of the battery branches with a preset total current threshold to obtain a first comparison result; comparing the single cell voltage of each battery branch with a preset single cell voltage threshold range to obtain a second comparison result.

[0011] Optionally, after obtaining the second comparison result, it also includes: when the first comparison result indicates that the total current of the battery branch within the target time period is greater than a preset total current threshold, determining that the battery branch meets the total current preset condition; when the second comparison result indicates that the single cell voltage of each of the battery branches is within a preset single cell voltage threshold range, determining that the battery branch meets the single cell voltage preset condition; when the battery branch meets the total current preset condition and the single cell voltage preset condition, determining that the multi-branch battery system meets the preset condition within the target time period.

[0012] Optionally, the step of calculating the power difference threshold of each of the battery branches includes: reading the branch current of each of the battery branches based on a current sensor; counting the number of battery cell strings in each of the battery branches; obtaining a preset first voltage reference value, and calculating the product of the branch current of each of the battery branches, the number of battery cell strings and the first voltage reference value to obtain the power difference threshold of each of the battery branches.

[0013] Optionally, the maximum power difference threshold is pre-calculated, and the steps of calculating the maximum power difference threshold include: reading the branch current of each battery branch based on the current sensor, and obtaining the maximum value of the branch current; counting the number of battery cell strings in each battery branch, and obtaining the maximum number of battery cell strings; obtaining a preset second voltage reference value, and calculating the product of the maximum value of each branch current, the maximum number of battery cell strings and the second voltage reference value to obtain the maximum power difference threshold.

[0014] Optionally, after generating a verification result based on the comparison result of the maximum power difference at all times within a preset time period, it also includes: when the verification result is a short circuit verification result, generating an alarm message based on the battery branch with a short circuit; generating a lower high voltage request based on the alarm message, and performing a lower high voltage operation on the target vehicle based on the lower high voltage request.

[0015] In the present application, the following steps are performed: after detecting that the target vehicle performs a high-voltage operation, the initial cumulative power of each battery branch in the multi-branch battery system of the target vehicle at the initial moment is read, and when the multi-branch battery system meets preset conditions within the target time period, the first cumulative power of each battery branch in the multi-branch battery system at the target moment is read, wherein the target moment is later than the initial moment, and then the power difference is calculated based on the initial cumulative power and the first cumulative power, and the power difference threshold of each battery branch is calculated, and finally the power difference of each battery branch is compared with the power difference threshold to obtain a power difference comparison result, and based on the power difference comparison result, it is determined whether there is a candidate battery branch with a circuit break; when there is a candidate battery branch with a circuit break in the multi-branch battery system, the circuit break condition of the candidate battery branch is verified to obtain a verification result, and a circuit break diagnosis result of the multi-branch battery system is generated based on the verification result.

[0016] In the present application, power detection is used to identify branches with broken circuits in a multi-branch battery system, and based on the accumulated power of each branch, it is determined whether there is a suspected broken branch, and a verification mechanism is configured to ensure the accuracy of the broken circuit fault diagnosis results. Based on power detection, the current entering the circuit can be effectively filtered out to avoid the circulation phenomenon caused by the differences in the battery cells in each branch, thereby achieving the purpose of reducing the risk of false alarms and the technical effect of improving the accuracy of broken circuit diagnosis in multi-branch battery systems, thereby solving the technical problem of low accuracy in the related art of judging the broken circuit condition of the battery branch by the current value. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 is a flow chart of an optional battery system circuit breaker diagnosis method based on power detection according to an embodiment of the present invention;

[0019] Figure 2 is an architecture diagram of an optional circuit breaker diagnosis system for an electric vehicle battery system according to an embodiment of the present invention;

[0020] Figure 3 It is a schematic diagram of an optional branch circuit breaking diagnosis process of a battery system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0022] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0023] To facilitate those skilled in the art to understand the present invention, some terms or nouns involved in the embodiments of the present invention are explained below:

[0024] Main Service Disconnect, referred to as MSD, is mainly used to provide a physical disconnect point between the battery pack and the high-voltage electrical system in the battery system. When the system needs maintenance or fails, MSD can safely disconnect the high-voltage circuit to protect maintenance personnel from electric shock hazards and protect the battery system from damage.

[0025] BMS master, namely Battery Management System main controller, is the core component of the battery management system, responsible for coordinating and controlling the operation of the entire battery system.

[0026] It should be noted that the power detection-based battery system short circuit diagnosis method and device thereof in the present application can be used in the field of battery fault diagnosis. When the short circuit fault diagnosis of the branch of the battery system is performed based on power detection, it can also be used in any field except the field of battery fault diagnosis. When the short circuit fault diagnosis of the branch of the battery system is performed based on power detection, the application field of the power detection-based battery system short circuit diagnosis method and device thereof is not limited in the present application.

[0027] It should be noted that the relevant information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are information and data authorized by the user or fully authorized by all parties, and the collection, storage, use, processing, transmission, provision, disclosure and application of the relevant data comply with the relevant laws, regulations and standards of the relevant regions, take necessary confidentiality measures, do not violate public order and good customs, and provide corresponding operation entrances for users to choose to authorize or refuse. For example, an interface is set up between this system and relevant users or organizations. Before obtaining relevant information, it is necessary to send an acquisition request to the aforementioned user or organization through the interface, and obtain relevant information after receiving the consent information fed back by the aforementioned user or organization.

[0028] It should be noted that in this application, when collecting and analyzing customer information, corresponding operation entrances are provided for users to choose to agree or reject the automated decision-making results; if the user chooses to reject, the expert decision-making process will be entered.

[0029] The following embodiments of the present invention can be applied to the diagnosis system / application / device of branch circuit breaking fault in various battery systems. The present invention uses the method of judging the cumulative power to detect branch circuit breaking, without adding additional devices, effectively reducing costs and reducing the complexity of logical control. Through power detection, there is no need to measure the branch current separately, which can avoid the current circulation phenomenon, make the relay report the correct state, reduce the risk of false alarms, and improve the accuracy of circuit breaking fault diagnosis. Based on the continuous detection within the target period, the initial verification result is verified to ensure the accuracy of the diagnosis result.

[0030] The present invention will be described in detail below with reference to specific embodiments.

[0031] According to an embodiment of the present invention, an embodiment of a battery system circuit short diagnosis method based on power detection is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0032] Figure 1 is a flow chart of an optional battery system open circuit diagnosis method based on power detection according to an embodiment of the present invention, such as Figure 1 As shown, the method comprises the following steps:

[0033] Step S101, after detecting that the target vehicle performs a high voltage operation, reading the initial accumulated power of each battery branch in the multi-branch battery system of the target vehicle at the initial moment.

[0034] It should be noted that the target vehicle can be an electric vehicle or hybrid vehicle using a multi-branch battery system. Based on the multi-branch battery system, each branch can be independently monitored and managed, and each branch may contain battery cells connected in series and in parallel. When the vehicle is started, it is necessary to perform a high-voltage operation. High voltage refers to connecting the vehicle's high-voltage battery system to the vehicle's high-voltage electrical system, so that the high-voltage battery can provide power to the motor and other high-voltage electrical equipment, so that the vehicle can operate normally. After detecting that the target vehicle performs a high-voltage operation, it is necessary to perform fault detection on the electric vehicle. Among them, the circuit breaker detection of the multi-branch battery system is one of the indispensable steps of fault detection. The circuit breaker of the battery branch has a significant impact on battery performance, vehicle safety, user driving experience, vehicle maintenance costs, etc.

[0035] It should be noted that after detecting high voltage on the vehicle, in order to ensure the accuracy of the collected signals and the read numbers, initialization filtering and waiting are required. The subsequent operations can be performed after the waiting signals (such as the current signals collected by the current sensor, etc.) and the BMS main control voltage are stable, so as to improve the accuracy of the diagnostic results. The waiting time can be set according to human experience.

[0036] It should be noted that after the multi-branch battery system is in a stable state, the initial cumulative power of each branch in the multi-branch battery system of the target vehicle is read at the initial moment. The cumulative power refers to the total power obtained by multiplying the current flowing through the battery branch by the branch voltage within a certain period of time. The initial cumulative power is the cumulative power over a period of time read at the initial moment. At the same time, the diagnostic system uses a timer to time and sets the values ​​of timer 1 and timer 2 to 0. The timer can set the accumulation period.

[0037] It should be noted that the accumulated power can be directly read by the BMS main control without installing additional plug-ins in the circuit. The BMS main control collects the voltage data and current data of each branch through the voltage sensor and current sensor. The voltage sensor is usually installed at the voltage end of each battery cell or branch, while the current sensor is installed on the current path of the branch to measure the current flowing through the branch. The accumulated power of each battery branch can be calculated through the voltage data and current data.

[0038] Optionally, before reading the first accumulated power of each battery branch in the multi-branch battery system at the target time, it also includes: collecting the total current of the battery branches of the multi-branch battery system within the target time period; collecting the single cell voltage of each battery branch of the multi-branch battery system within the target time period; comparing the total current of the battery branches with a preset total current threshold to obtain a first comparison result; comparing the single cell voltage of each battery branch with a preset single cell voltage threshold range to obtain a second comparison result.

[0039] It should be noted that when diagnosing a circuit breaker fault on each branch, it is first necessary to determine whether the multi-branch battery system meets the preset conditions, and perform circuit breaker fault diagnosis when the preset conditions are met. The preset conditions include: the total current of the battery branches is greater than the preset total current threshold, and the single cell voltage of each battery branch is within the preset single cell voltage threshold range, thereby eliminating the influence of small current on branch circuit breaker faults and the influence of single cell abnormalities on branch circuit breaker faults. Specifically, the total current of the battery branches of the multi-branch battery system within the target time period and the single cell voltage of each battery branch are collected. The target time period can be an accumulation cycle of a timer, and then the total current of the battery branches is compared with the preset total current threshold, and the single cell voltage of each battery branch is compared with the preset single cell voltage threshold range to determine whether the multi-branch battery system meets the preset conditions.

[0040] Optionally, after obtaining the second comparison result, it also includes: when the first comparison result indicates that the total current of the battery branch within the target time period is greater than a preset total current threshold, determining that the battery branch meets the total current preset condition; when the second comparison result indicates that the single cell voltage of each battery branch is within a preset single cell voltage threshold range, determining that the battery branch meets the single cell voltage preset condition; when the battery branch meets the total current preset condition and the single cell voltage preset condition, determining that the multi-branch battery system meets the preset condition within the target time period.

[0041] It should be noted that for a multi-branch battery system to meet the preset conditions, it is necessary to ensure that the total current of the battery branches within the target time period is greater than the preset total current threshold and the single cell voltage of each battery branch is within the preset single cell voltage threshold range, so as to determine whether the multi-branch battery system meets the preset conditions within the target time period. The accuracy of the observation data can be ensured by continuously observing whether the multi-branch battery system meets the preset conditions within multiple target time periods, so as to improve the accuracy of the open circuit fault diagnosis. If the multi-branch battery system does not meet the preset conditions within the preset time period, continue to wait until the multi-branch battery system meets the preset conditions.

[0042] Step S102: when the multi-branch battery system meets a preset condition within a target time period, read the first accumulated power of each battery branch in the multi-branch battery system at the target time.

[0043] It should be noted that after determining that the multi-branch battery system meets the preset conditions, timer 1 is used to count the time and read the first cumulative power of each battery branch at the target time. The target time is later than the initial time, that is, the first cumulative power at the target time is actually the cumulative power of the battery branch in the entire time period before the target time.

[0044] Step S103: Calculate the power difference based on the initial accumulated power and the first accumulated power, and calculate the power difference threshold of each battery branch.

[0045] It should be noted that after reading the initial cumulative power and the first cumulative power, the absolute value of the difference between the first cumulative power and the initial cumulative power is calculated through the difference algorithm, and the power difference threshold of each battery branch is calculated. The power difference threshold is determined by the voltage reference value determined based on experience and the number of battery cell strings and branch current of each battery branch.

[0046] Optionally, the step of calculating the power difference threshold of each battery branch includes: reading the branch current of each battery branch based on a current sensor; counting the number of battery cell strings in each battery branch; obtaining a preset first voltage reference value, and calculating the product of the branch current of each battery branch, the number of battery cell strings and the first voltage reference value to obtain the power difference threshold of each battery branch.

[0047] It should be noted that the operation and maintenance personnel can set the voltage reference value based on historical experience to obtain the first voltage reference value. The voltage reference value is generally relatively small, for example, 5mV. In the real-time short-circuit fault diagnosis process, the pre-set first voltage reference value is called, and the branch current of each battery branch is read through the current sensor, and the number of battery cell strings of each battery branch is counted, so as to calculate the power difference threshold of each battery branch based on the first voltage reference value, the branch current and the number of battery cell strings. The power difference threshold limits the minimum value of the power change of the battery branch. If the cumulative power of each battery branch is less than the power difference threshold, the power change of the battery branch can be ignored, that is, the power of the battery branch does not rise or fall within a detection cycle, and it is determined that the branch is suspected of having a short circuit fault.

[0048] Step S104, comparing the power difference of each battery branch with the power difference threshold to obtain a power difference comparison result, and determining whether there is a candidate battery branch with a circuit breaker based on the power difference comparison result.

[0049] It should be noted that after comparing the power difference of each battery branch with the power difference threshold, if the power difference of a branch is less than the power difference threshold, the branch is regarded as a candidate battery branch with a short circuit, and the short circuit condition of the candidate battery branch is subsequently verified. Conversely, if the power difference of the battery branches are all less than the power difference threshold, it indicates that the power of each branch has increased or decreased, and there is no risk of branch short circuit.

[0050] Step S105, when there is a candidate battery branch with a circuit break in the multi-branch battery system, verify the circuit break status of the candidate battery branch to obtain a verification result, and generate a circuit break diagnosis result of the multi-branch battery system based on the verification result.

[0051] It should be noted that if there are candidate battery branches with short circuits in the multi-branch battery system, it is also necessary to verify the short circuit status of the candidate battery branch to determine whether the candidate battery branch does have a short circuit fault, and then generate a short circuit diagnosis result for the multi-branch battery system.

[0052] Optionally, the step of verifying the short circuit condition of the candidate battery branch to obtain the verification result includes: counting the cumulative power of each battery branch at each moment in a preset time period, wherein the duration of the preset time period is greater than the duration of the target time period; sorting the cumulative power of each battery branch at each moment to obtain a sorting result; and verifying the short circuit condition of the candidate battery branch based on the sorting result at each moment to obtain a verification result.

[0053] It should be noted that when checking the circuit breakage, timer 2 is used to count the cumulative power of each battery branch at each moment within a preset time period. The preset time period can be an observation time starting from the target moment, which is much longer than the target time period for observing whether the multi-branch battery system meets the preset conditions. Then the cumulative power at each moment is sorted, and the maximum and minimum cumulative power at each moment are used to determine whether the battery branch does have a circuit breakage fault. When the performance of the battery cells is not much different and there is no branch circuit breakage, the difference between the maximum and minimum cumulative power of each branch should not be too large. If the difference between the maximum and minimum cumulative power of the battery branch is very different for a period of time, it proves that a battery branch is broken and no charging or discharging is performed, resulting in the stability of the cumulative power of this battery branch. Therefore, the difference between the maximum and minimum cumulative power is so large.

[0054] Optionally, the open circuit condition of the candidate battery branch is verified based on the sorting result at each moment to obtain the step of verification result, including: extracting the maximum and minimum cumulative power values ​​at each moment from the sorting result at each moment, and calculating the difference between the maximum and minimum cumulative power values ​​at each moment to obtain the maximum power difference at each moment; obtaining a preset maximum power difference threshold, and verifying the open circuit condition of the candidate battery branch based on the maximum power difference at each moment and the preset maximum power difference threshold to obtain the verification result.

[0055] Specifically, the cumulative power at each moment is sorted, the maximum cumulative power and the minimum cumulative power are selected, and the difference between the maximum cumulative power and the minimum cumulative power is calculated to obtain the maximum power difference at each moment, and the maximum power difference at each moment is compared with the preset maximum power difference threshold, thereby determining the verification result of the candidate battery branch circuit breaker condition based on the comparison result.

[0056] Optionally, the maximum power difference threshold is calculated in advance, and the steps of calculating the maximum power difference threshold include: reading the branch current of each battery branch based on the current sensor, and obtaining the maximum value of the branch current; counting the number of battery cell strings in each battery branch, and obtaining the maximum number of battery cell strings; obtaining a preset second voltage reference value, and calculating the product of the maximum value of each branch current, the maximum number of battery cell strings and the second voltage reference value to obtain the maximum power difference threshold.

[0057] It should be noted that the maximum power difference threshold can be calculated based on the maximum voltage reference value (i.e., the second voltage reference value) obtained from historical experience and the number of battery cell strings and the branch current in the battery branch. The maximum voltage reference value is slightly larger than the first voltage reference value, and can be set to 40mV, for example. Specifically, the maximum branch current value of each battery branch is read and the maximum number of battery cell strings of each battery branch is determined, and the product of the preset maximum voltage base value and the maximum branch current value and the maximum number of battery cell strings is calculated to obtain the maximum power difference threshold of each branch.

[0058] Optionally, a preset maximum power difference threshold is obtained, and the open circuit condition of the candidate battery branch is verified based on the maximum power difference value at each moment and the preset maximum power difference threshold, and the step of obtaining the verification result includes: comparing the maximum power difference value at each moment with the maximum power difference threshold to obtain the maximum power difference comparison result at each moment; counting the maximum power difference comparison results of all moments within a preset time period, and generating a verification result based on the maximum power difference comparison results of all moments within the preset time period, wherein, when the maximum power difference comparison results of all moments within the preset time period indicate that the maximum power difference is greater than the maximum power difference threshold, it is determined that the candidate battery branch is open circuit, and the open circuit verification result is obtained.

[0059] It should be noted that the maximum power difference at each moment is compared with the maximum power difference threshold. If the maximum power difference is greater than the maximum power difference threshold, it indicates that there is a broken battery branch in the multi-branch battery system and no charging or discharging is performed, resulting in the stability of the cumulative power of this branch. Therefore, the difference between the maximum and minimum cumulative power values ​​is quite large. After obtaining the maximum power difference threshold at each moment, the maximum power difference comparison results at all moments in the preset time period are statistically analyzed. If the maximum power difference is continuously greater than the maximum power difference threshold within the target time period, it is determined that the candidate battery branch is missing and there is a broken circuit, and then the broken circuit verification result is generated.

[0060] Optionally, after generating a verification result based on the comparison result of the maximum power difference at all times within a preset time period, it also includes: when the verification result is a short circuit verification result, generating an alarm message based on the battery branch with a short circuit; generating a low-voltage request based on the alarm message, and performing a low-voltage operation on the target vehicle based on the low-voltage request.

[0061] It should be noted that the high-voltage operation after the branch circuit is disconnected is an important safety measure in the battery system. It can timely cut off the connection between the battery and the high-voltage system, prevent potential dangers and damage, and ensure the safety of the system and personnel. In order to ensure the safety of the vehicle, after detecting that there is a battery branch with a circuit breaker fault in the multi-branch battery system, an alarm information is generated according to the battery branch with the circuit breaker, and then a high-voltage request is generated to request the target vehicle to lower the high voltage. In a multi-branch battery system, if a branch circuit is broken, the battery cell of the branch will not be able to participate in the normal charging and discharging process. However, current may still flow through other branches, resulting in uneven current and voltage distribution in the entire system. In a high-voltage system, this imbalance may cause the battery cells of the remaining branches to be subjected to abnormally high current or voltage, thereby increasing the risk of fire, explosion or electric shock. The high-voltage operation can quickly cut off the connection between the battery and the high-voltage electrical system to avoid dangerous situations. In addition, branch circuit breaking may cause some parts of the system to be overloaded, such as overcurrent or overvoltage, which not only damages the battery cell itself, but also may damage other components in the high-voltage electrical system, such as inverters, motor drivers, etc. Lowering the voltage prevents this overload condition and protects sensitive components in the system from damage.

[0062] Through the above steps, after detecting that the target vehicle performs a high-voltage operation, the initial cumulative power of each battery branch in the multi-branch battery system of the target vehicle at the initial moment is read, and when the multi-branch battery system meets the preset conditions within the target time period, the first cumulative power of each battery branch in the multi-branch battery system at the target moment is read, wherein the target moment is later than the initial moment, and then the power difference is calculated based on the initial cumulative power and the first cumulative power, and the power difference threshold of each battery branch is calculated, and finally the power difference of each battery branch is compared with the power difference threshold to obtain a power difference comparison result, and based on the power difference comparison result, it is determined whether there is a candidate battery branch with a circuit break; when there is a candidate battery branch with a circuit break in the multi-branch battery system, the circuit break condition of the candidate battery branch is verified to obtain a verification result, and a circuit break diagnosis result of the multi-branch battery system is generated based on the verification result.

[0063] In this embodiment, power detection is used to identify branches with broken circuits in a multi-branch battery system, and based on the accumulated power of each branch, it is determined whether there is a suspected broken branch, and a verification mechanism is configured to ensure the accuracy of the broken circuit fault diagnosis results. Based on power detection, the current entering the circuit can be effectively filtered out to avoid the circulation phenomenon caused by the differences in the battery cells in each branch, thereby achieving the purpose of reducing the risk of false alarms and the technical effect of improving the accuracy of broken circuit diagnosis in multi-branch battery systems, thereby solving the technical problem of low accuracy in the related art of judging the broken circuit condition of the battery branch by the current value.

[0064] Another optional specific implementation is described in detail below.

[0065] Figure 2 is an optional circuit breaker diagnosis system architecture diagram of an electric vehicle battery system according to an embodiment of the present invention, such as Figure 2 As shown in the figure, the disconnection diagnosis system of the electric vehicle battery system is based on the BMS main control, current sensor and shunt to collect and read data, and determine whether there is a branch disconnection fault in the electric vehicle battery system by accumulating power. Specifically, the shunt is connected to the negative electrode of the battery branch to detect the total current flowing through the battery branch, and the current sensor is connected to the negative electrode of each battery branch ( Figure 3 The negative poles of battery branch 1, battery branch 2 and battery branch 3 are used to detect each battery branch ( Figure 3 The figure shows three battery branches, namely battery branch 1, battery branch 2 and battery branch 3). The positive pole of the battery branch is connected to its corresponding main isolating switch (MSD). The BMS master control can obtain the battery cell voltage and the cumulative total voltage of each branch through internal communication, and then calculate the cumulative power of each battery branch based on the branch current obtained by the current sensor.

[0066] Figure 3 is a schematic diagram of an optional branch circuit breaker diagnosis process of a battery system according to an embodiment of the present invention, such as Figure 3 As shown in FIG. 1 , the branch circuit breaking diagnosis process of the battery system specifically includes:

[0067] Step 1: Initialization: First, filter and wait for 100ms (other values ​​are also possible, 100ms is used as an example here) to wait for the signal (such as the current data collected by the current sensor) and the BMS main control voltage to stabilize;

[0068] Step 2: After 100ms of initialization, read the value of the accumulated power P_Back (corresponding to the above initial accumulated power) of each branch, and set the timer T1 (corresponding to the above timer 1 and timer 2) and T2 to 0, and the timer has a 10ms accumulation period;

[0069] Step 3: Determine whether the total current is greater than the preset total current threshold and the cell voltage meets the preset cell voltage threshold. If so, execute step 4. If not, return to step 2. The total current read by the shunt is greater than 50A (an example value of the total current threshold, or other values), indicating that the target vehicle is in a relatively large current discharge or charging process at this moment, eliminating the influence of small current on branch circuit breaker faults. And the read cell voltage needs to be within the threshold range of 2.8V to 3.5V (an example value of the cell voltage threshold range, or other values), eliminating the influence of cell abnormality on branch circuit breaker faults;

[0070] Step 4: Determine whether T1 is greater than the first preset time threshold. If so, execute step 5. If not, return to step 3. When the total current value and the single cell voltage meet the preset conditions, determine whether the timer T1 is greater than 100ms. If not, continue to wait. The purpose is to filter and eliminate the impact of current and single cell voltage jumps. Because the call cycle is 10ms, the total current and single cell voltage will be detected 10 times in 100ms. If the detection is within the normal range for 10 times, the data is considered reliable;

[0071] Step 5, read the accumulated power P of each branch;

[0072] Step 6: Calculate the difference between the P_Back value and the P value to get |P-P_Back|, and determine whether |P-P_Back| is less than the power difference threshold. If so, it proves that the power of the branch has not increased or decreased in the past 100ms, and there may be a branch disconnection. Go to step 7. If not, it proves that the power of each branch has increased or decreased, and there is no risk of branch disconnection, and return to step 2;

[0073] Step 7, calculate the maximum and minimum accumulated power of each branch, and determine whether the maximum and minimum accumulated power of each branch are greater than the maximum power difference threshold, so as to check the branch with possible circuit breaker fault in step 6, if yes, execute step 8, if not, return to step 2;

[0074] When the performance of the battery cells is not much different and there is no branch circuit breakage, the difference between the maximum and minimum cumulative power of each branch should not be too large. If the difference between the maximum and minimum cumulative power of each branch is greater than the maximum power difference threshold, it proves that the branch that may have a circuit breakage fault is not charged or discharged, resulting in the stability of the cumulative power of this branch, so the difference between the maximum and minimum cumulative power is large.

[0075] Step 8, determine whether T2 is greater than the second preset time threshold, if not, return to step 6, if yes, execute step 9, continue to judge within the second preset time threshold, if both the maximum and minimum values ​​of the accumulated power of each branch are greater than the maximum power difference threshold, it proves that there is indeed a branch circuit breaker fault;

[0076] Step nine, determine that the branch circuit is broken, issue an alarm, and request high voltage to be applied to the target vehicle.

[0077] In the embodiment of the present invention, the branch circuit is detected by judging the accumulated power, without adding additional devices, effectively reducing costs and reducing the complexity of logic control. Through power detection, there is no need to measure the branch current separately, which can avoid the current circulation phenomenon, make the relay report the correct state, reduce the risk of false alarms, and improve the accuracy of circuit breaker fault diagnosis. Based on the continuous detection within the target cycle, the initial verification result is verified to ensure the accuracy of the diagnosis result.

[0078] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0079] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0080] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0081] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0082] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0083] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

[0084] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A battery system circuit breaker diagnosis method based on power detection, characterized in that: include: After detecting that the target vehicle performs a high voltage operation, reading the initial accumulated power of each battery branch in the multi-branch battery system of the target vehicle at the initial moment; When the multi-branch battery system meets a preset condition within a target time period, reading a first accumulated power of each battery branch in the multi-branch battery system at a target time, wherein the target time is later than the initial time; Calculating a power difference value based on the initial cumulative power and the first cumulative power, and calculating a power difference threshold value of each of the battery branches; Comparing the power difference of each of the battery branches with the power difference threshold to obtain a power difference comparison result, and determining whether there is a candidate battery branch with a circuit breaker based on the power difference comparison result; In the case that there are candidate battery branches with circuit breaks in the multi-branch battery system, the circuit break conditions of the candidate battery branches are verified to obtain verification results, and circuit break diagnosis results of the multi-branch battery system are generated based on the verification results.

2. The method according to claim 1, characterized in that The step of verifying the disconnection condition of the candidate battery branch to obtain a verification result comprises: Counting the cumulative power of each battery branch at each moment in a preset time period, wherein the duration of the preset time period is greater than the duration of the target time period; Sorting the accumulated power of each battery branch at each moment to obtain a sorting result; Based on the ranking result at each moment, the circuit breaking condition of the candidate battery branch is verified to obtain a verification result.

3. The method according to claim 2, characterized in that The step of verifying the disconnection condition of the candidate battery branch based on the sorting result at each moment to obtain the verification result comprises: Extracting the maximum and minimum values ​​of the cumulative power at each moment from the sorting results at each moment, and calculating the difference between the maximum and minimum values ​​of the cumulative power at each moment to obtain the maximum power difference at each moment; A preset maximum power difference threshold is obtained, and the disconnection condition of the candidate battery branch is verified based on the maximum power difference value at each moment and the preset maximum power difference threshold to obtain a verification result.

4. The method according to claim 3, characterized in that The step of obtaining a preset maximum power difference threshold, verifying the disconnection condition of the candidate battery branch based on the maximum power difference value at each moment and the preset maximum power difference threshold, and obtaining a verification result includes: Compare the maximum power difference value at each moment with the maximum power difference threshold to obtain a maximum power difference comparison result at each moment; The maximum power difference comparison results at all moments within a preset time period are counted, and a verification result is generated according to the maximum power difference comparison results at all moments within the preset time period, wherein, when the maximum power difference comparison results at all moments within the preset time period indicate that the maximum power difference is greater than the maximum power difference threshold, it is determined that there is a short circuit in the candidate battery branch, and a short circuit verification result is obtained.

5. The method according to claim 1, characterized in that Before reading the first accumulated power of each battery branch in the multi-branch battery system at the target time, the method further includes: Collecting the total current of the battery branches of the multi-branch battery system within a target time period; Collecting the single cell voltage of each battery branch of the multi-branch battery system within a target time period; Comparing the total current of the battery branch with a preset total current threshold to obtain a first comparison result; The cell voltage of each of the battery branches is compared with a preset cell voltage threshold range to obtain a second comparison result.

6. The method according to claim 5, characterized in that After obtaining the second comparison result, the method further includes: When the first comparison result indicates that the total current of the battery branch within the target time period is greater than a preset total current threshold, determining that the battery branch meets a preset total current condition; When the second comparison result indicates that the cell voltages of the battery branches are all within a preset cell voltage threshold range, determining that the battery branches meet a preset cell voltage condition; When the battery branch meets the total current preset condition and the single cell voltage preset condition, it is determined that the multi-branch battery system meets the preset condition within the target time period.

7. The method according to claim 1, characterized in that The step of calculating the power difference threshold of each battery branch includes: Reading the branch current of each of the battery branches based on the current sensor; Counting the number of battery cell strings in each of the battery branches; A preset first voltage reference value is obtained, and the product of the branch current of each battery branch, the number of battery cell strings and the first voltage reference value is calculated to obtain a power difference threshold of each battery branch.

8. The method according to claim 3, characterized in that The maximum power difference threshold is calculated in advance, and the step of calculating the maximum power difference threshold includes: Reading the branch current of each battery branch based on the current sensor, and obtaining the maximum value of the branch current; Counting the number of battery cell strings of each battery branch and obtaining the maximum number of battery cell strings; A preset second voltage reference value is obtained, and the product of the maximum value of each branch current, the maximum value of the number of battery cell strings and the second voltage reference value is calculated to obtain the maximum power difference threshold.

9. The method according to claim 4, characterized in that After generating the verification result according to the maximum power difference comparison result at all times within the preset time period, the method further includes: If the verification result is a circuit-breaking verification result, generating an alarm message based on the battery branch circuit having a circuit-breaking; A lower high-voltage request is generated based on the warning information, and a lower high-voltage operation is performed on the target vehicle based on the lower high-voltage request.

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