A wire breakage detection method and system, battery device

Abstract

The application provides a disconnection detection method and system and a battery device, which respectively perform pull-up and pull-down on different collection channels, and detect the voltage values of the battery cells after the collection channels are turned on; the detected voltage values are respectively judged in the a-th period and the b-th period, in the a-th period, whether the positive and negative collection channels of the corresponding battery cell exist disconnection is judged according to the relationship between the voltage value corresponding to each battery cell and the first range; for the collection channels without detected disconnection, in the b-th period, whether the positive and negative collection channels of the corresponding battery cell exist disconnection is judged according to the change degree of the voltage value corresponding to each battery cell compared with the voltage value corresponding to each battery cell in the a-th period; the method can greatly accelerate the disconnection detection speed on one hand, and does not need to consider the initial value of the battery cell, thus avoiding the misjudgment caused by the voltage difference of different battery cells and the channel impedance difference.

Description

Technical Field

[0001] This invention relates to the field of batteries, and more particularly to a method and system for detecting broken wires, and a battery device. Background Technology

[0002] In the Battery Management System (BMS), a key component of new energy vehicles, a cell acquisition chip is used to detect the status of the battery cells. Specifically, each cell's positive and negative terminals correspond to a data acquisition channel coupled to the cell acquisition chip, which then detects the status of each cell through these channels. Please refer to [reference needed]. Figure 1 In this system, each acquisition channel consists of a channel bundle, with one end connected to the positive and negative terminals of the battery cell via a resistor, and the other end connected to the acquisition pins of the battery cell acquisition chip via a resistor. Simultaneously, to ensure balanced discharge of the battery cell, a corresponding equalization pin is provided on the battery cell acquisition chip, connected to the acquisition channel bundle of the corresponding channel via a resistor. Traditional technology typically encapsulates the channel portion near the acquisition and equalization pins and mounts it on a PCB board, while the channel portion near the positive and negative terminals of the battery cell acts as a connector. Therefore, disconnection detection between the battery cell acquisition chip and the battery cell is crucial.

[0003] Existing broken line detection solutions mainly include:

[0004] 1. Wire breakage detection is performed by monitoring the on / off state of the equalization switch inside the battery cell acquisition chip. However, this solution has a problem: it can only detect wire breakage in the connector section of the acquisition channel; if the wire breakage occurs on the PCB board within the acquisition channel, it cannot be detected.

[0005] 2. This method uses the built-in current source of the battery cell acquisition chip to pull up / down current through each channel to detect open circuit faults. When a cell's voltage is detected to be above / below a set voltage range, the corresponding channel for that cell's positive and negative terminals is considered open. While this solution can detect open circuits across the entire acquisition channel, it has a drawback: when a channel is open, the corresponding cell is not immediately detected as being above / below the set voltage range. The detected voltage increases / decreases over a period of time until it exceeds / belows the set voltage range. This delay is primarily caused by the port capacitance at the acquisition pins of the battery cell acquisition chip and the built-in current source used for pull-up / pull-down current. This excessively long detection time prevents the battery management system from promptly detecting open circuits in the acquisition channel, potentially leading to other vehicle malfunctions.

[0006] Therefore, providing a fast and comprehensive method for detecting broken wires across the entire acquisition channel has become a pressing technical problem for the industry. Summary of the Invention

[0007] To address the above problems, the present invention provides a method and system for detecting broken wires, and a battery device.

[0008] According to a first aspect of the present invention, a method for detecting broken wires is provided for detecting broken wires in a cascaded battery cell structure and a data acquisition channel connecting each battery cell data acquisition chip; wherein the cascaded battery cell structure includes n battery cells connected in series, and the positive and negative terminals of each battery cell are respectively connected to the corresponding detection ports of the data acquisition chips of each battery cell through a data acquisition channel; wherein the data acquisition channels are sequentially ordered, the data acquisition channel connected to the negative terminal of the first battery cell is denoted as the 0th data acquisition channel, and the data acquisition channel connected to the positive terminal of the nth battery cell is denoted as the nth data acquisition channel; n is a positive integer, and n≥2; the method includes:

[0009] Pull up or pull down the positive and negative acquisition channels of the first cell to the nth cell respectively;

[0010] Starting with the first cell, the positive and negative acquisition channels of each cell are sequentially turned on within one cycle, and the voltage value corresponding to each cell is detected. The voltage value corresponding to each cell is used to characterize the voltage difference between the positive and negative acquisition channels of the corresponding cell when they are turned on.

[0011] During the a-th cycle, based on the relationship between the voltage value of each cell and the first range, it is determined whether there is a break in the positive and negative electrode acquisition channel of the corresponding cell;

[0012] For acquisition channels where no disconnection was detected, in the b-th cycle, based on the degree of change of the voltage value corresponding to each cell compared to the voltage value corresponding to the a-th cycle, it is determined whether there is a disconnection in the positive and negative acquisition channels of the corresponding cell.

[0013] Where i, a, and b are all positive integers, and 1 ≤ a < b, 1 ≤ i < n.

[0014] Optionally, within the a-th cycle, based on the relationship between the voltage value of each cell and the first range, it is determined whether there is a break in the positive and negative electrode acquisition channels of the corresponding cell, specifically including:

[0015] If the positive and negative acquisition channels of the battery cell are pulled up, then based on whether the voltage value of the corresponding battery cell is lower or higher than the first range, it is determined that there is a break in the negative acquisition channel or the positive acquisition channel of the corresponding battery cell.

[0016] If the positive and negative electrode acquisition channels of the battery cell are pulled down, it can be determined that there is a break in the negative electrode acquisition channel or the positive electrode acquisition channel of the corresponding battery cell, depending on whether the voltage value of the corresponding battery cell is higher or lower than the first range.

[0017] Optionally, for cells where no open circuit was detected in the positive and negative electrode acquisition channels, during the b-th cycle, the degree of change in the voltage value of each cell compared to the voltage value in the a-th cycle is used to determine whether there is an open circuit in the positive and negative electrode acquisition channels of the corresponding cell. Specifically, this includes:

[0018] If the positive and negative electrode acquisition channels of the battery cell are pulled up and no open circuit is detected, then in the b-th cycle, if the voltage value of the corresponding battery cell decreases or increases by more than the first threshold compared to the voltage value in the a-th cycle, it is determined that the negative electrode acquisition channel or the positive electrode acquisition channel of the corresponding battery cell is open.

[0019] If the positive and negative electrode acquisition channels of a battery cell are pulled down and no disconnection is detected, then in the b-th cycle, if the voltage value of each battery cell increases or decreases by more than the second threshold compared to the voltage value in the a-th cycle, it is determined that the negative electrode acquisition channel or the positive electrode acquisition channel of the corresponding battery cell is disconnected.

[0020] Optionally, in the b-th cycle, if the positive and negative acquisition channels of the battery cell are pulled up and a break in the positive or negative acquisition channel is detected, then the positive and negative acquisition channels of the battery cell are pulled down in the subsequent cycles; if the positive and negative acquisition channels of the battery cell are pulled down and a break in the positive or negative acquisition channel is detected, then the positive and negative acquisition channels of the battery cell are pulled up in the subsequent cycles.

[0021] Optionally, if a disconnection is detected in the positive acquisition channel of the j-th cell, but no disconnection is detected in the negative acquisition channel of the i-th cell, then it is determined that the positive acquisition channel of the i-th cell also has a disconnection; where i and j are positive integers, and i = j + 1, 1 ≤ j < i ≤ n.

[0022] Optionally, if a disconnection is detected in the negative electrode acquisition channel of the j-th cell, but no disconnection is detected in the positive electrode acquisition channel of the i-th cell, then it is determined that the negative electrode acquisition channel of the i-th cell is also disconnected; where i and j are positive integers, and j = i + 1, 1 ≤ i < j ≤ n.

[0023] Optionally, the positive and negative acquisition channels of the second cell to the (n-1)th cell can be pulled up or pulled down respectively. Specifically, this includes: pulling up the positive and negative acquisition channels of the second cell to the jth cell; and pulling down the positive and negative acquisition channels of the i-th cell to the (n-1)th cell. Here, i and j are positive integers, and i = j + 1, 1 ≤ j < i ≤ n-1.

[0024] Optionally, the positive and negative acquisition channels of the second cell to the (n-1)th cell can be pulled up or pulled down respectively. Specifically, from the second cell to the (n-1)th cell, the positive and negative acquisition channels of even-numbered cells are pulled up, and the positive and negative acquisition channels of odd-numbered cells are pulled down.

[0025] Optionally, the duration of one cycle is in milliseconds.

[0026] According to a second aspect of the present invention, a wire breakage detection system is provided for implementing the wire breakage detection method provided in the first aspect and optional embodiments of the present invention. The system includes:

[0027] The pull-up / pull-down module is used to pull up or pull down the positive and negative acquisition channels of the first cell to the nth cell respectively.

[0028] A multiplexer module is coupled to the pull-up / pull-down module; the multiplexer module is used to control the positive and negative acquisition channels of each cell to be turned on sequentially within one cycle;

[0029] A detection module is coupled to the pull-up / pull-down module; the detection module is used to detect the voltage value corresponding to each cell; wherein, the voltage value corresponding to each cell is used to characterize the voltage difference between the positive and negative acquisition channels of the corresponding cell when they are turned on;

[0030] A judgment module is coupled to the detection module; the judgment module is used to determine whether there is a break in the positive and negative electrode acquisition channel of the corresponding cell within the a-th cycle, based on the relationship between the voltage value of each cell and the first range.

[0031] For acquisition channels where no disconnection was detected, in the b-th cycle, based on the degree of change of the voltage value corresponding to each cell compared to the voltage value corresponding to the a-th cycle, it is determined whether there is a disconnection in the positive and negative acquisition channels of the corresponding cell.

[0032] Where a and b are both positive integers, and 1 ≤ a < b.

[0033] Optionally, the pull-up / pull-down module specifically includes several bus channels and corresponding pull-up units; wherein, each bus channel is used to integrate several acquisition channels, and pulls up or down the integrated acquisition channels through the corresponding pull-up unit.

[0034] According to a third aspect of the present invention, a battery device is provided, including the wire breakage detection system provided in the second aspect of the present invention.

[0035] The open circuit detection method provided by this invention involves pulling up / down different acquisition channels and detecting the voltage value of the battery cell after the acquisition channel is turned on. Within the first cycle (a), based on the relationship between the voltage value of each battery cell and a first range, it is determined whether there is an open circuit in the positive and negative acquisition channels of the corresponding battery cell. If an open circuit is detected within this cycle, it indicates that the open circuit time of the corresponding acquisition channel has exceeded the time mentioned in the background art. For acquisition channels where no open circuit is detected, within the second cycle (b), based on the degree of change of the voltage value of each battery cell compared to the voltage value in the first cycle (a), it is determined whether there is an open circuit in the positive and negative acquisition channels of the corresponding battery cell. After two cycles (b), the voltage value of the battery cell is detected again. If the degree of change of the voltage value detected in the first cycle (a) exceeds a set threshold, an open circuit can be determined. Compared to existing technologies that only judge open circuits based on a single voltage value, judging open circuits by the difference in voltage values ​​detected at similar times can greatly shorten the detection time. Attached Figure Description

[0036] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0037] Figure 1 A circuit diagram corresponding to existing technology for detecting broken wires;

[0038] Figure 2 The circuit structure diagram corresponding to the open circuit detection method provided in the first embodiment of the present invention;

[0039] Figure 3 A flowchart of a wire breakage detection method provided in the first embodiment of the present invention. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of the present invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the present invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0041] Before explaining the embodiments of the present invention, the design concept of the present invention will be briefly described first:

[0042] The principle behind existing technologies for detecting open circuits by pulling up / down the acquisition channel using a built-in current source is as follows: Cell voltage detection is achieved by measuring the voltage difference between the positive and negative terminals of the corresponding acquisition channel. When there is no open circuit in the acquisition channel, pulling up / down will not affect the voltage. Therefore, the detected voltage will be within a normal range; for example, if the voltage of a single cell is 4V, a measured voltage between 3.5V and 4.5V is within the normal range. If an open circuit occurs in the positive acquisition channel of any cell, pulling up / down will increase / decrease the voltage of the acquisition channel. When the acquisition channel is fully pulled up or down, the detected voltage value of the corresponding cell will be higher / lower than the normal range; pulling up the positive acquisition channel of the corresponding cell will result in a detected voltage value higher than 4.5V, for example, 5V-6V; pulling down the positive acquisition channel of the corresponding cell will result in a detected voltage value lower than 3.5V, for example, 1V-2V. Of course, the specific values ​​will depend on the selected pull-up / pull-down current source, switch on-resistance, and battery voltage, and are not limited here. However, in the initial stage of a disconnection, the voltage of the acquisition channel will not increase / decrease rapidly due to the port capacitance at the pins of the battery cell acquisition chip. Therefore, existing technologies require a long time to detect a disconnection in the acquisition channel, making timely detection difficult and potentially leading to other malfunctions. As can be seen above, detecting a disconnection in the acquisition channel by solely judging the battery cell voltage value is affected by the port capacitance and cannot be detected in a timely manner. Although the channel voltage will not cause the detected voltage value to quickly exceed the normal range when a disconnection occurs, it will still cause a change in the detected voltage value. Therefore, if a change in voltage value is detected within a short period of time, it can be determined that there is a disconnection in the positive and negative acquisition channels of the battery cell, and the direction of the voltage change can be used to determine whether the disconnection occurred in the positive or negative acquisition channel. Of course, the above-mentioned detected voltage change value will have a normal range, but this normal voltage change is generally due to the normal charging and discharging of the battery cell, usually measured in hours. The cell voltage does not change significantly in a short period of time, especially on a second-by-second basis, unless a disconnection occurs. Therefore, judging whether a disconnection has occurred in the acquisition channel by whether the voltage value changes within a short period of time can help detect disconnection problems in the acquisition channel in a timely manner.

[0043] Please refer to Figure 2 and Figure 3The first embodiment of the present invention provides a disconnection detection method for detecting disconnections in a data acquisition channel connecting a cascaded battery cell structure and individual battery cell acquisition chips. The cascaded battery cell structure includes n battery cells connected in series, with the positive and negative terminals of each cell connected to the corresponding detection port of the individual battery cell acquisition chip via a data acquisition channel. The data acquisition channels are sequentially ordered, with the data acquisition channel connected to the negative terminal of the first battery cell designated as acquisition channel 0, and the data acquisition channel connected to the positive terminal of the nth battery cell designated as acquisition channel n. n is a positive integer, and n ≥ 2. The method includes:

[0044] S1: Pull up or pull down the positive and negative acquisition channels of the first cell to the nth cell respectively. Of course, the current source in the figure is only one way to implement pull up / pull down. Pull up and pull down resistors can also be used to pull up and down the acquisition channels. It should be noted that all devices with pull up and pull down functions fall within the protection scope of this invention.

[0045] Specifically, the positive and negative electrode acquisition channels of the first to the nth battery cell are pulled up or down. This involves dividing the first to the nth battery cells into three groups, pulling up all positive and negative electrode acquisition channels in the first group; pulling up all positive and negative electrode acquisition channels of the even-numbered cells in the second group, and pulling down all positive and negative electrode acquisition channels of the odd-numbered cells in the second group; and pulling down all positive and negative electrode acquisition channels of the cells in the third group. Of course, dividing the first to the nth battery cells into three groups is just one implementation method; it can be divided into i groups as needed, without limitation. Here, i is a positive integer, and 1 ≤ i ≤ n. Furthermore, the number of cells in each group and the pull-up / pull-down settings for the positive and negative electrode acquisition channels can be configured according to requirements, without limitation.

[0046] S2: Starting from the first cell, control the positive and negative acquisition channels of each cell to be turned on sequentially within one cycle, and detect the voltage value corresponding to each cell; wherein, the voltage value corresponding to each cell is used to characterize the voltage difference between the positive and negative acquisition channels of the corresponding cell when they are turned on.

[0047] S3: During the a-th cycle, based on the relationship between the voltage value of each cell and the first range, determine whether there is a break in the positive and negative electrode acquisition channel of the corresponding cell.

[0048] S4: For cells where no open circuit was detected in the positive and negative electrode acquisition channels, in the b-th cycle, determine whether there is an open circuit in the positive and negative electrode acquisition channels of the corresponding cells based on the degree of change of the corresponding voltage value in the a-th cycle.

[0049] Where i, a, and b are all positive integers, and a≥1, b≥1, 1≤i<n.

[0050] The first embodiment of the present invention achieves full coverage and rapid disconnection detection of the acquisition channel through the above-described technical solution. Its principle is as follows:

[0051] From acquisition channel 0 to acquisition channel n, the voltage corresponding to each acquisition channel continuously increases. For low acquisition channels, due to the lower voltage, pull-up pull-ups are suitable for disconnection detection. For high acquisition channels, due to the higher voltage, pull-down pull-ups are suitable for disconnection detection. Of course, the choice of acquisition channels for pull-down and pull-up pull-ups can be made based on actual needs and is not limited here. Next, the positive and negative acquisition channels of each cell are sequentially turned on within one cycle to detect the voltage value of each cell. Pull-ups or pull-downs of the acquisition channels do not have an immediate effect; therefore, the voltage value of each cell is detected only after several cycles.

[0052] For the pull-up acquisition channel, if the detected voltage value is below the first range (i.e., below the normal range of the cell voltage), it can be determined that there is a break in the negative acquisition channel of the corresponding cell. This is because when the negative acquisition channel of the cell is broken and fully pulled up, while the positive acquisition channel is normal, the detected voltage value—the difference between the voltages of the corresponding positive and negative channels—will decrease and fall below the normal range. If the detected voltage value is above the first range, it can be determined that there is a break in the positive acquisition channel of the corresponding cell. This is because when the positive acquisition channel of the cell is broken and fully pulled up, while the negative acquisition channel is normal, the detected voltage value will increase and rise above the normal range. If the detected voltage value is within the normal range, it indicates that there is no break in the positive and negative acquisition channels of the corresponding cell, or that a break has occurred but occurred only recently, thus not immediately causing the voltage value to exceed the normal range. To quickly determine the latter situation, the voltage value of each cell is re-detected after several cycles. If the voltage value of each cell is detected to be lower than the voltage value of the previous test, and the degree of drop exceeds the set threshold, it is determined that there is a break in the negative electrode acquisition channel of the corresponding cell. This is because when the negative electrode acquisition channel of a cell is broken, it is pulled up by the current source or pull-up resistor, and gradually increases due to the presence of port capacitance. Although the detected voltage value is within the normal range, because the cell voltage does not fluctuate by the set threshold value in a short period of time, the current detected voltage value is lower than the previous detected voltage value and exceeds the set threshold, thus indicating a break in the negative electrode acquisition channel of the corresponding cell. If the voltage value of each cell is detected to be higher than the voltage value of the previous test, and the degree of increase exceeds the set threshold, it is determined that there is a break in the positive electrode acquisition channel of the corresponding cell. When the positive electrode acquisition channel of the battery cell is disconnected, it will be pulled by the pull-up current source or pull-up resistor, and gradually increase due to the presence of port capacitance. Although the detected voltage value is within the normal range, the battery cell voltage will not fluctuate by the set threshold size in a short period of time. Therefore, the voltage value detected this time is higher than the voltage value detected last time and exceeds the set threshold, which can determine that there is a disconnection in the positive electrode acquisition channel of the corresponding battery cell.

[0053] The principle for detecting disconnection in the pull-down acquisition channel is the opposite of that in the pull-up acquisition channel, and will not be elaborated here.

[0054] Furthermore, since the time of a cycle is set to the millisecond level, the time difference for detecting the cell voltage value is also in the millisecond level. That is, the time for detecting the disconnection of the acquisition channel is in the millisecond level. Compared with the detection time of the existing technology which requires the second level, this greatly speeds up the detection speed of the acquisition channel and can achieve the same detection coverage as the existing technology.

[0055] The following explains other aspects of the wire breakage detection method:

[0056] As a specific implementation method, in S3, during the a-th cycle, based on the relationship between the voltage value corresponding to each cell and the first range, it is determined whether there is a break in the positive and negative electrode acquisition channels of the corresponding cell, specifically including:

[0057] During the a-th cycle, if the positive and negative electrode acquisition channels of the battery cell are pulled up, then based on whether the voltage value of the corresponding battery cell is lower or higher than the first range, it is determined that there is a disconnection in the negative electrode acquisition channel or the positive electrode acquisition channel of the corresponding battery cell.

[0058] If the positive and negative electrode acquisition channels of the battery cell are pulled down, it can be determined that there is a break in the negative electrode acquisition channel or the positive electrode acquisition channel of the corresponding battery cell, depending on whether the voltage value of the corresponding battery cell is higher or lower than the first range.

[0059] As a specific implementation, in S4, for battery cells where no open circuit was detected in the positive and negative electrode acquisition channels, during the b-th cycle, the degree of change in the voltage value corresponding to each battery cell compared to the voltage value corresponding to the a-th cycle is used to determine whether there is an open circuit in the positive and negative electrode acquisition channels of the corresponding battery cell. Specifically, this includes:

[0060] If the positive and negative electrode acquisition channels of the battery cell are pulled up and no open circuit is detected, then in the b-th cycle, if the voltage value of the corresponding battery cell decreases or increases by more than the first threshold compared to the voltage value in the a-th cycle, it is determined that the negative electrode acquisition channel or the positive electrode acquisition channel of the corresponding battery cell is open.

[0061] If the positive and negative electrode acquisition channels of a battery cell are pulled down and no disconnection is detected, then in the b-th cycle, if the voltage value of each battery cell increases or decreases by more than the second threshold compared to the voltage value in the a-th cycle, it is determined that the negative electrode acquisition channel or the positive electrode acquisition channel of the corresponding battery cell is disconnected.

[0062] In one specific implementation, if a break in the positive or negative acquisition channel of a battery cell is detected during the b-th cycle, a reverse load method is used to apply load to the positive and negative channels of the cell for several cycles to avoid false positives. For example, if the positive and negative channels of the cell were previously pulled upwards, they are now pulled downwards for several cycles; if the positive and negative channels of the cell were previously pulled downwards, they are now pulled upwards for several cycles. After several cycles of reverse load application, if a break in the positive or negative acquisition channel of the cell is still detected, the accuracy of the break is confirmed. The number of reverse load cycles can be set according to requirements and is not limited here.

[0063] In one specific implementation, if a break in the positive electrode acquisition channel of the j-th cell is detected, but no break in the negative electrode acquisition channel of the i-th cell is detected, then it is determined that the positive electrode acquisition channel of the i-th cell also has a break; where i and j are positive integers, and i = j + 1, 1 ≤ j < i ≤ n. The principle is as follows: When a break in the positive electrode acquisition channel of the j-th cell is detected, and this acquisition channel also serves as the negative electrode acquisition channel of the i-th cell, when detecting the voltage value of the i-th cell, if the detected voltage value is within a first range in the a-th cycle, and the change in the detected voltage value compared to the voltage value detected in the a-th cycle is less than a first threshold in the b-th cycle, then it indicates that the negative electrode acquisition channel of the i-th cell does not have a break, but a break in the positive electrode acquisition channel of the j-th cell is detected, then it can be determined that the positive electrode acquisition channel of the i-th cell also has a break. When the positive and negative acquisition channels of each battery cell are disconnected, the corresponding channel voltages will change synchronously. Therefore, it is impossible to detect whether there is a disconnection in the acquisition channel by the voltage difference between the positive and negative channel voltages. In this case, the disconnection status of the next battery cell can be determined by detecting the disconnection of the previous battery cell.

[0064] As a supplementary embodiment, if a break in the positive electrode acquisition channel of the j-th cell is detected, while no break is detected in the negative electrode acquisition channel of the (j+1)-th cell or the negative electrode acquisition channels of subsequent cells, then it is determined that a break exists in the positive electrode acquisition channel of the i-th cell and the positive electrode acquisition channels of subsequent cells. The principle can be extended from the above embodiment; for example, if a break is detected in the positive electrode acquisition channel of the second cell, but no break is detected in the negative electrode acquisition channel of the third cell, then it can be determined that a break exists in the positive electrode acquisition channel of the third cell. If no break is detected in the negative electrode acquisition channels of subsequent cells, then based on the third cell, it can also be determined that a break exists in the positive electrode acquisition channels of subsequent cells.

[0065] In one specific implementation, if a break in the negative electrode acquisition channel of the j-th cell is detected, but no break in the positive electrode acquisition channel of the i-th cell is detected, then it is determined that the negative electrode acquisition channel of the i-th cell also has a break; where i and j are positive integers, and j = i + 1, 1 ≤ i < j ≤ n. The principle is as follows: when a break in the negative electrode acquisition channel of the j-th cell is detected, and this acquisition channel also serves as the positive electrode acquisition channel of the i-th cell, when detecting the voltage value of the i-th cell, if the detected voltage value is within a first range in the a-th cycle, and the change in the detected voltage value compared to the voltage value detected in the a-th cycle is less than a first threshold in the b-th cycle, then it indicates that the positive electrode acquisition channel of the i-th cell does not have a break, but a break in the negative electrode acquisition channel of the j-th cell is detected, then it can be determined that the negative electrode acquisition channel of the i-th cell also has a break. When both the positive and negative acquisition channels of each battery cell are disconnected, the corresponding channel voltages will change synchronously. Therefore, it is impossible to detect whether there is a disconnection in the acquisition channel by the voltage difference between the positive and negative channel voltages. In this case, the disconnection status of the previous battery cell can be determined by detecting the disconnection of the next battery cell.

[0066] As a supplementary embodiment, if a break in the negative electrode acquisition channel of the j-th cell is detected, while no break in the positive electrode acquisition channels of the (j-1)-th cell to the first cell is detected, then it is determined that all the positive electrode acquisition channels of the (j-1)-th cell to the first cell are broken. The principle can be extended from the above embodiment; for example, if a break in the negative electrode acquisition channel of the 5th cell is detected, while no break in the positive electrode acquisition channel of the 4th cell is detected, then it can be determined that the negative electrode acquisition channel of the 4th cell is broken. If no break in the positive electrode acquisition channels of the preceding cells is detected, then based on the 4th cell, it can also be determined that the negative electrode acquisition channels of the preceding cells are also broken.

[0067] In one specific implementation, the time of one cycle is on the order of milliseconds; for example, 1ms can be set as one cycle. The voltage value of each cell is checked after 10 cycles, and then checked again after another 10 cycles. This allows for disconnection detection in just 20ms, significantly accelerating the detection speed compared to existing technologies that require seconds. Of course, the time of one cycle can be set according to requirements and is not limited here. The first range can be set on the order of millivolts; for example, 100mV-200mV, to improve the accuracy of disconnection detection in the acquisition channel. The specific value of the first range can also be set according to requirements and is not limited here.

[0068] In summary, the disconnection detection method provided in the first embodiment of the present invention determines whether there is a disconnection in the corresponding acquisition channel by detecting whether the voltage value of the battery cell fluctuates beyond a set threshold within a short period of time. On the one hand, it can greatly speed up the disconnection detection process; on the other hand, it does not need to consider the initial value of the battery cell, thus avoiding misjudgments caused by voltage differences and channel impedance differences between different battery cells.

[0069] Please refer to Figure 2 A second embodiment of the present invention provides a wire breakage detection system for implementing the wire breakage detection method provided in the first embodiment; the system includes:

[0070] The pull-up / pull-down module is used to pull up or pull down the positive and negative acquisition channels of the first cell to the nth cell respectively.

[0071] A multiplexer module is coupled to the pull-up / pull-down module; the multiplexer module is used to control the positive and negative acquisition channels of each cell to be turned on sequentially within one cycle;

[0072] A detection module is coupled to the pull-up / pull-down module; the detection module is used to detect the voltage value corresponding to each cell; wherein, the voltage value corresponding to each cell is used to characterize the voltage difference between the positive and negative acquisition channels of the corresponding cell when they are turned on;

[0073] The judgment module is coupled to the detection module;

[0074] The judgment module is used to determine whether there is a disconnection in the positive and negative electrode acquisition channels of the corresponding battery cell within the a-th cycle, based on the relationship between the voltage value of each battery cell and the first range.

[0075] For acquisition channels where no disconnection was detected, in the b-th cycle, based on the degree of change of the voltage value corresponding to each cell compared to the voltage value corresponding to the a-th cycle, it is determined whether there is a disconnection in the positive and negative acquisition channels of the corresponding cell.

[0076] Where i, a, and b are all positive integers, and a≥1, b≥1, 1≤i<n.

[0077] Please refer to Figure 2As a supplementary explanation, to facilitate control of the acquisition channels, the n acquisition channels can be divided into two parts based on the degree of voltage accumulation. Acquisition channels 1 to 1 are integrated through a first bus channel, and acquisition channels (i+1) to n are integrated through a second bus channel. Then, the first bus channel is pulled up or pulled down using a first pull-up unit, and the second bus channel is pulled up or pulled down using a second pull-up unit, reducing the number of pull-up units and lowering circuit costs. For example, with a total of 16 acquisition channels, acquisition channels 0 to 8 are integrated into a first bus channel, and acquisition channels 9 to 16 are integrated into a second bus channel. Then, the first bus channel is pulled up, and the second bus channel is pulled down. Of course, the n acquisition channels can also be divided into 3, 4, or more bus channels; the specific number of divisions can be set according to requirements and is not limited here.

[0078] Please refer to Figure 2 In one specific implementation, the load-pull unit includes a current source; it may also include a load-pull resistor or other devices with load-pull capability. Of course, the specific choice can be made according to requirements and is not limited here. It should be noted that if the bus channel is pulled up, the bus channel is connected to the pull-up power supply through the load-pull unit; if the bus channel is pulled down, the bus channel is connected to ground through the load-pull unit.

[0079] A third embodiment of the present invention provides a battery device including the aforementioned wire breakage detection system.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for detecting broken wires, used to detect broken wires in a data acquisition channel connecting a cascaded battery cell structure and a battery cell acquisition chip; wherein, The cascaded battery cell structure comprises n battery cells connected in series. The positive and negative terminals of each battery cell are connected to the corresponding detection ports of the battery cell acquisition chip via a separate acquisition channel. The acquisition channels are sequentially ordered, with the acquisition channel connected to the negative terminal of the first battery cell designated as acquisition channel 0, and the acquisition channel connected to the positive terminal of the nth battery cell designated as acquisition channel n. n is a positive integer, and n ≥ 2. The method is characterized by comprising: Pull up or pull down the positive and negative acquisition channels of the first cell to the nth cell respectively; Starting with the first cell, the positive and negative acquisition channels of each cell are sequentially turned on within one cycle, and the voltage value corresponding to each cell is detected. The voltage value corresponding to each cell is used to characterize the voltage difference between the positive and negative acquisition channels of the corresponding cell when they are turned on. During the a-th cycle, based on the relationship between the voltage value of each cell and the first range, it is determined whether there is a break in the positive and negative electrode acquisition channel of the corresponding cell; For cells where no open circuit was detected in the positive and negative electrode acquisition channels, in the b-th cycle, the degree of change of the corresponding voltage value of the corresponding cell compared with the corresponding voltage value in the a-th cycle is used to determine whether there is an open circuit in the positive and negative electrode acquisition channels of the corresponding cell. Where a and b are both positive integers, and 1 ≤ a < b; If the positive and negative acquisition channels of the battery cell are pulled up, then based on whether the voltage value of the corresponding battery cell is lower or higher than the first range, it is determined that there is a break in the negative acquisition channel or the positive acquisition channel of the corresponding battery cell. If the positive and negative electrode acquisition channels of the battery cell are pulled down, it can be determined whether the negative electrode acquisition channel or the positive electrode acquisition channel of the corresponding battery cell is disconnected, depending on whether the voltage value of the corresponding battery cell is higher or lower than the first range. If the positive and negative electrode acquisition channels of the battery cell are pulled up and no open circuit is detected, then in the b-th cycle, if the voltage value of the corresponding battery cell decreases or increases by more than the first threshold compared to the voltage value in the a-th cycle, it is determined that the negative electrode acquisition channel or the positive electrode acquisition channel of the corresponding battery cell is open. If the positive and negative electrode acquisition channels of the battery cell are pulled down and no disconnection is detected, then in the b-th cycle, if the voltage value of each battery cell increases or decreases by more than the second threshold compared to the voltage value in the a-th cycle, it is determined that the negative electrode acquisition channel or the positive electrode acquisition channel of the corresponding battery cell is disconnected. In the b-th cycle, if the positive and negative acquisition channels of the battery cell are pulled up and a break in the positive or negative acquisition channel is detected, then the positive and negative acquisition channels of the battery cell will be pulled down in the following cycles; if the positive and negative acquisition channels of the battery cell are pulled down and a break in the positive or negative acquisition channel is detected, then the positive and negative acquisition channels of the battery cell will be pulled up in the following cycles.

2. The wire breakage detection method according to claim 1, characterized in that, If a disconnection is detected in the positive acquisition channel of the j-th cell, but no disconnection is detected in the negative acquisition channel of the i-th cell, then it is determined that the positive acquisition channel of the i-th cell also has a disconnection; where i and j are positive integers, and i = j + 1, 1 ≤ j < i ≤ n.

3. The wire breakage detection method according to claim 1, characterized in that, If a disconnection is detected in the negative electrode acquisition channel of the j-th cell, but no disconnection is detected in the positive electrode acquisition channel of the i-th cell, then it is determined that the negative electrode acquisition channel of the i-th cell also has a disconnection; where i and j are positive integers, and j = i + 1, 1≤i<j≤n.

4. The wire breakage detection method according to claim 1, characterized in that, Pull-up or pull-down can be applied to the positive and negative acquisition channels of the first cell to the nth cell, including: pulling up all positive and negative acquisition channels of the first cell to the nth cell, or pulling down all positive and negative acquisition channels of the first cell to the nth cell.

5. The wire breakage detection method according to claim 1, characterized in that, The positive and negative acquisition channels of the first cell to the nth cell are pulled up or pulled down respectively. Specifically, from the first cell to the nth cell, the positive and negative acquisition channels of even-numbered cells are pulled up, and the positive and negative acquisition channels of odd-numbered cells are pulled down.

6. The wire breakage detection method according to claim 1, characterized in that, The duration of one cycle is in milliseconds.

7. A wire breakage detection system, used to implement the wire breakage detection method according to any one of claims 1 to 5; characterized in that, The system includes: The pull-up / pull-down module is used to pull up or pull down the positive and negative acquisition channels of the first cell to the nth cell respectively. A multiplexer module is coupled to the pull-up / pull-down module; the multiplexer module is used to control the positive and negative acquisition channels of each cell to be turned on sequentially within one cycle; A detection module is coupled to the pull-up / pull-down module; the detection module is used to detect the voltage values ​​corresponding to the positive and negative terminals of each cell; wherein, the voltage value corresponding to each cell is used to characterize the voltage difference between the positive and negative terminal acquisition channels of the corresponding cell when they are turned on; A judgment module is coupled to the detection module; the judgment module is used to determine whether there is a break in the positive and negative electrode acquisition channel of the corresponding cell within the a-th cycle, based on the relationship between the voltage value of each cell and the first range. For acquisition channels where no disconnection was detected, in the b-th cycle, based on the degree of change of the voltage value corresponding to each cell compared to the voltage value corresponding to the a-th cycle, it is determined whether there is a disconnection in the positive and negative acquisition channels of the corresponding cell. Where a and b are both positive integers, and 1 ≤ a < b.

8. The wire breakage detection system according to claim 7, characterized in that, The pull-up / pull-down module specifically includes several bus channels and corresponding pull-up units; wherein, each bus channel is used to integrate several acquisition channels, and pulls up or down the integrated acquisition channels through the corresponding pull-up unit.

9. A battery device, characterized in that, Includes the wire breakage detection system as described in claim 7 or 8.

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