Leaking cell detection system and method

Abstract

A leaking cell detection system according to an embodiment of the present invention may comprise: a gas sensor for generating, using a resistance value varying according to an electrolyte leaking from a battery cell, a measurement value that varies according to a concentration of the leaked electrolyte; and a control unit for calculating a time variation of the measurement value and Bollinger Bands of the time variation, generating a leaking cell determination graph for the battery cell by arranging the time variation, an upper band of the Bollinger Bands, and a lower band of the Bollinger Bands in chronological order, and determining whether the battery cell is a leaking cell, on the basis of whether the leaking cell determination graph includes a first point at which the time variation falls below the lower band of the Bollinger Bands and a second point at which the time variation rises above the upper band of the Bollinger Bands.

Description

Leak cell detection system and method

[0001] Cross-citation with related application(s)

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0157021 filed November 7, 2024, and all contents disclosed in the document of said Korean patent application are incorporated herein as part of this specification.

[0003] The present invention relates to a system and method for detecting a leak cell among a plurality of battery cells.

[0004] A leak cell refers to a battery cell among multiple cells contained within a battery that leaks electrolyte. Electrolyte leakage in battery cells can primarily occur due to factors such as excessive welding, leading to various problems. For instance, electrolyte leakage blocks the lithium ion migration pathway, degrading battery performance, and reduces battery lifespan due to internal chemical imbalances. Furthermore, leakage of electrolytes containing flammable substances increases the risk of fire or explosion, and if the electrolyte comes into contact with internal battery components, corrosion may occur, exacerbating cell damage.

[0005] In conventional technology, multiple gas sensors were assigned one-to-one to each of the multiple battery cells within a completed battery to determine whether there was electrolyte leakage. For example, multiple gas sensors were attached to a board and brought close to each of the multiple battery cells via a cylinder to check for electrolyte leakage at the top of the battery cell. In this case, when the gas sensor detects an organic compound, its resistance decreases and it generates an output value proportional to the resistance; electrolyte leakage is determined by whether the converted value calculated based on the gas sensor's output value exceeds a specific threshold value. However, conventional technology has problems, such as different determination results appearing for the same leak cell depending on the gas sensor due to deviations in each gas sensor.

[0006] The present invention aims to provide a method and system capable of accurately detecting leak cells despite variations among gas sensors by using Bollinger bands.

[0007] A leak cell detection system according to one embodiment of the present invention may include a gas sensor that generates a measurement value that changes according to the concentration of the leaked electrolyte using a resistance value that changes according to the electrolyte leaking from the battery cell, and a control unit that calculates the time change amount of the measurement value and the Bollinger band of the time change amount, generates a leak cell judgment graph for the battery cell by arranging the time change amount, the upper limit of the Bollinger band, and the lower limit of the Bollinger band in chronological order, and determines whether the battery cell is a leak cell based on whether the leak cell judgment graph includes a first point where the time change amount goes down through the lower limit of the Bollinger band and a second point where the time change amount goes up through the upper limit of the Bollinger band.

[0008] The above gas sensor can be transported by a transport device to be close to the battery cell and then transported away from the battery cell.

[0009] The control unit may include a calculation unit that receives the measurement value at each measurement cycle and calculates the time change amount by dividing the difference between the first measurement value generated in this measurement cycle and the second measurement value generated in the previous cycle by the measurement cycle.

[0010] The control unit may include a calculation unit that calculates the moving average and standard deviation of the time change amount, calculates the upper limit of the Bollinger band by arranging the values ​​obtained by adding a certain multiple of the standard deviation to the moving average in chronological order, and calculates the lower limit of the Bollinger band by arranging the values ​​obtained by subtracting a certain multiple of the standard deviation from the moving average in chronological order.

[0011] The control unit may include a leak cell determination unit that receives movement data of the gas sensor from a storage unit and, using the time at which the movement of the gas sensor starts and the time at which the movement of the gas sensor stops included in the movement data, extracts a gas sensor movement section corresponding to the time when the gas sensor approaches and moves away from the battery cell in the leak cell determination graph.

[0012] The control unit may include a leak cell determination unit that determines that the battery cell is a leak cell if the first point and the second point are included in the gas sensor movement section, and determines that the battery cell is not a leak cell if the first point or the second point is not included in the gas sensor movement section.

[0013] A leak cell detection method according to an embodiment of the present invention may include: a calculation unit calculating a time change amount of a measurement value and a Bollinger band of the time change amount using a measurement value received from a gas sensor; a leak cell determination unit generating a leak cell determination graph for a specific battery cell by arranging the time change amount received from the calculation unit and the upper and lower limits of the Bollinger band in chronological order; the leak cell determination unit extracting a gas sensor movement section corresponding to the time during which the gas sensor approaches and moves away from the specific battery cell in the leak cell determination graph; and the leak cell determination unit determining whether the battery cell is a leak cell based on whether the gas sensor movement section includes a first point where the time change amount goes down through the lower limit of the Bollinger band and a second point where the time change amount goes up through the upper limit of the Bollinger band.

[0014] The step of calculating the time change amount and Bollinger band may include receiving the measurement value at each measurement cycle, and calculating the time change amount by dividing the difference between the first measurement value generated in this measurement cycle and the second measurement value generated in the previous cycle by the measurement cycle.

[0015] The step of calculating the time change amount and the Bollinger band may include the step of calculating the moving average and standard deviation of the time change amount, the step of calculating the upper limit of the Bollinger band by arranging the values ​​obtained by adding a certain multiple of the standard deviation to the moving average in chronological order, and the step of calculating the lower limit of the Bollinger band by arranging the values ​​obtained by subtracting a certain multiple of the standard deviation from the moving average in chronological order.

[0016] The step of extracting the gas sensor movement section may include receiving movement data of the gas sensor from a storage unit, and extracting the gas sensor movement section from the leak cell judgment graph using the time when the movement of the gas sensor starts and the time when the movement of the gas sensor stops included in the movement data.

[0017] The step of determining whether the battery cell is a leak cell may include a step of determining that the battery cell is a leak cell if the first point and the second point are included in the gas sensor movement section, and a step of determining that the battery cell is not a leak cell if the first point or the second point is not included in the gas sensor movement section.

[0018] According to one embodiment of the present invention, a leak cell can be accurately determined among a plurality of battery cells included in a battery despite deviations between gas sensors.

[0019] The effects obtainable from the present disclosure are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure belongs from the description below.

[0020] FIG. 1 is a block diagram of a leak cell detection system according to one embodiment of the present invention.

[0021] FIG. 2 is a drawing for explaining a gas sensor according to one embodiment of the present invention.

[0022] FIG. 3 is a graph showing the measured values ​​generated over time as a gas sensor according to one embodiment of the present invention approaches and moves away from a battery cell that is not a leak cell.

[0023] FIG. 4 is a graph showing the measurement values ​​generated over time as a gas sensor according to one embodiment of the present invention approaches and moves away from a battery cell that is a leak cell.

[0024] FIG. 5 is an example of a graph showing the measured values ​​generated by a gas sensor according to one embodiment of the present invention arranged in chronological order.

[0025] FIG. 6 is an example of a leak cell determination graph generated by a control unit according to an embodiment of the present invention.

[0026] FIG. 7 is a flowchart of a leak cell detection method according to one embodiment of the present invention.

[0027] In describing the embodiments disclosed in this specification, detailed descriptions of related prior art are omitted if it is determined that such detailed descriptions may obscure the essence of the embodiments disclosed in this specification. Furthermore, the attached drawings are intended only to facilitate understanding of the embodiments disclosed in this specification, and the technical concept disclosed in this specification is not limited by the attached drawings; it should be understood that they include all modifications, equivalents, and substitutions that fall within the spirit and technical scope of the invention.

[0028] Terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but said components are not limited by said terms. These terms are used solely for the purpose of distinguishing one component from another.

[0029] When it is stated that one component is "connected" or "connected" to another component, it should be understood that while it may be directly connected or connected to that other component, there may also be other components in between. On the other hand, when it is stated that one component is "directly connected" or "directly connected" to another component, it should be understood that there are no other components in between.

[0030] In this application, terms such as “comprising” or “having” are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0031] The present invention will be described in detail below with reference to the attached drawings.

[0032] FIG. 1 is a block diagram of a leak cell detection system (100) according to one embodiment of the present invention.

[0033] Referring to FIG. 1, a leak cell detection system (100) according to one embodiment of the present invention may include a gas sensor (110), a control unit (120), and a storage unit (130).

[0034] The gas sensor (110) can generate a measurement value that varies according to the concentration of the leaked electrolyte by utilizing a resistance value that varies according to the electrolyte leaking from the battery cell. Here, the measurement value is data generated by detecting the concentration of the electrolyte leaking from the battery cell, is generated by the gas sensor (110), and is inversely proportional to the concentration of the electrolyte.

[0035] For example, the gas sensor (110) may include a Metal Oxide Semiconductor (MOS) element (111). Gas generated from the leaked electrolyte is adsorbed onto the surface of the MOS element (111) of the gas sensor (110), causing an oxidation or reduction reaction on the surface of the MOS element (111), thereby changing the resistance value of the MOS element (111). At this time, when the gas generated from the leaked electrolyte (e.g., volatile organic compounds or corrosive gases of the electrolyte) is adsorbed onto the MOS element (111), it improves the conductivity of the MOS element (111) and promotes the movement of electrons, so the resistance of the MOS element (111) decreases. That is, the higher the concentration of the leaked electrolyte, the higher the concentration of the gas generated from the leaked electrolyte, so the resistance value of the MOS element (111) decreases. The gas sensor (110) can measure the resistance value of the MOS element (111). Hereinafter, the resistance value of the MOS element (111) measured by the gas sensor (110) is described as a measurement value indicating the electrolyte leaked from a specific battery cell (hereinafter, leakage electrolyte concentration).

[0036] The control unit (120) can receive a measurement value for the concentration of electrolyte leaked from a specific battery cell from a gas sensor (110). The control unit (120) can calculate the time change amount of the measurement value and the Bollinger band of the time change amount. Based on the relationship between the time change amount and the Bollinger band, the control unit (120) can determine whether the battery cell is a leak cell. According to an embodiment, the control unit (120) may include a calculation unit (121) and a leak cell determination unit (122). The components of the control unit (120) according to an embodiment of the present invention will be described in more detail below with reference to FIGS. 5 and FIGS.

[0037] The storage unit (130) may store movement data of the gas sensor (110) and leak cell determination results, which will be described later.

[0038] According to an embodiment, the leak cell detection system (100) may include a display (not shown in the drawing). The display may receive a leak cell determination graph and a leak cell determination result including a time change amount and a Bollinger band from a control unit (120), and may provide the received leak cell determination graph and leak cell determination result to a user.

[0039]

[0040] FIG. 2 is a drawing for explaining a gas sensor (110) according to one embodiment of the present invention.

[0041] Referring to FIG. 2, a leak cell detection system (100) according to one embodiment of the present invention may include a plurality of gas sensors (110). The plurality of gas sensors (110) may be transported by a transport device (10) to be close to and away from a plurality of battery cells (20).

[0042] At this time, the transfer device (10) may be controlled by the control unit (120) of the leak cell detection system (100) or by an external device (not shown in the drawing), and information regarding the movement of a plurality of gas sensors (110) by the transfer device (10) may be transmitted and stored as movement data in the storage unit (130) of the leak cell detection system (100). Here, the movement data may include information regarding the direction of movement of the gas sensor (110), the time at which movement begins, and the time at which movement stops.

[0043] For example, each of the multiple battery cells (20) corresponding to the leak cell detection target can be transported by a transport roller (40) in a form stored in a cell tray (30). At this time, the cell tray (30) can move along the lower part of the transport device (10), and the transport roller (40) can temporarily stop operation when the cell tray (30) reaches a specific position. That is, the transport roller (40) can be controlled so that the cell tray (30) stops for a short time at a specific position. At this time, the specific position where the cell tray (30) stops for a short time may be a position where each of the multiple battery cells (20) is matched 1:1 with each of the multiple gas sensors (110). When the cell tray (30) reaches a specific position, the transport device (10) can perform the operation of lowering and then raising the multiple gas sensors (110). As a result, each of the multiple gas sensors (110) can move closer to and further away from each of the multiple battery cells (20).

[0044] In FIG. 2, a transfer device (10) is illustrated as comprising a board (11) on which a plurality of gas sensors (110) are installed and arranged, and a transfer member (12) (e.g., a cylinder, etc.) for transferring the board (11) up and down. However, the configuration of the transfer device (10) according to the present invention is not limited thereto, and the configuration and operation method of the transfer device (10) can be freely changed according to the embodiment.

[0045] Referring to FIG. 2, each of the plurality of gas sensors (110) can generate each of the plurality of measurement values ​​while moving closer to and further away from each of the plurality of battery cells (20). Each of the plurality of gas sensors (110) can transmit each of the plurality of measurement values ​​generated while moving closer to and further away from each of the plurality of battery cells (20) to the calculation unit (121). At this time, the measurement value generated by the gas sensor (110) may be inversely proportional to the concentration of the electrolyte detected by the gas sensor (110) while the gas sensor (110) moves closer to and further away from the battery cell (20).

[0046] FIG. 3 is a graph showing, over time, the measurement values ​​generated by a gas sensor (110) according to one embodiment of the present invention while approaching and moving away from a battery cell that is not a leak cell, and FIG. 4 is a graph showing, over time, the measurement values ​​generated by a gas sensor (110) according to one embodiment of the present invention while approaching and moving away from a battery cell that is a leak cell.

[0047] Referring to FIG. 3, changes in the measurement value generated by the gas sensor (110) can be seen while the gas sensor (110) approaches and moves away from the battery cell that is not the leak cell.

[0048] Sections A to B of FIG. 3 correspond to the period while the gas sensor (110) approaches the battery cell, and sections B to C of FIG. 3 correspond to the period while the gas sensor (110) moves away from the battery cell.

[0049] That is, when the battery cell is not a leak cell, there is no change in the concentration of the electrolyte detected by the gas sensor (110) while the gas sensor (110) approaches and moves away from the battery cell, so there is no change in the measurement value generated by the gas sensor (110).

[0050] Referring to FIG. 4, changes in the measurement value generated by the gas sensor (110) can be seen while the gas sensor (110) approaches and moves away from the battery cell that is the leak cell.

[0051] Sections A through B of FIG. 4 correspond to the period during which the gas sensor (110) approaches the leak cell. In this section (A → B), as the gas sensor (110) approaches the leak cell, the concentration of the electrolyte detected by the gas sensor (110) increases, so the measurement value generated by the gas sensor (110) decreases.

[0052] Sections B through C of Fig. 4 correspond to the period during which the gas sensor (110) moves away from the leak cell. In this section (B → C), as the gas sensor (110) moves away from the leak cell, the concentration of the electrolyte detected by the gas sensor (110) decreases, and thus the measurement value generated by the gas sensor (110) increases.

[0053] That is, when the battery cell is a leak cell, the measurement value measured by the gas sensor (110) decreases rapidly and then increases rapidly while the gas sensor (110) approaches and moves away from the battery cell.

[0054] FIG. 5 is an example of a graph in which measurement values ​​generated by a gas sensor (110) according to an embodiment of the present invention are arranged in chronological order, and FIG. 6 is an example of a leak cell determination graph generated by a control unit (120) according to an embodiment of the present invention.

[0055] Referring to FIG. 1, a control unit (120) according to one embodiment of the present invention may include a calculation unit (121) and a leak cell determination unit (122).

[0056] The calculation unit (121) can receive a measurement value for the concentration of the electrolyte leaking from the battery cell from the gas sensor (110) at each measurement cycle. Here, the measurement cycle refers to the period during which the gas sensor (110) detects the electrolyte leaking from the battery cell and generates a measurement value inversely proportional to the concentration of the electrolyte. At this time, the calculation unit (121) can receive a measurement value for each of the multiple battery cells corresponding to the leak cell detection target.

[0057] The calculation unit (121) can calculate the amount of time change of the measured value. Here, the amount of time change refers to the rate of change of the measured value over time, and means the amount of change of the measured value per unit time. According to the embodiment, the unit time of the amount of time change may be seconds (sec). At this time, the calculation unit (121) can calculate the amount of time change for each of the plurality of battery cells corresponding to the leak cell detection target.

[0058] According to an embodiment, the calculation unit (121) can calculate the amount of time change by dividing the difference between the first measurement value generated in this measurement cycle and the second measurement value generated in the previous measurement cycle by the measurement cycle. For example, if the gas sensor (110) generates a measurement value at a measurement cycle interval of 10 seconds, the calculation unit (121) can calculate the amount of time change by dividing the difference between the first measurement value generated in this measurement cycle and the second measurement value generated in the previous measurement cycle by 10 seconds.

[0059] The calculation unit (121) can calculate Bollinger bands using the time change amount (2). Here, Bollinger bands are a data analysis tool that visualizes the variability of data and can be calculated based on the moving average and standard deviation of the data. Bollinger bands may include an upper limit (1) and a lower limit (3). If the gap between the upper limit (1) and the lower limit (3) of the Bollinger band widens, it means that the variability of the data is large, and if the gap between the upper limit (1) and the lower limit (3) narrows, it means that the variability of the data is small. At this time, the calculation unit (121) can calculate Bollinger bands for each of the multiple battery cells corresponding to the leak cell detection target.

[0060] According to an embodiment, the calculation unit (121) can calculate the moving average and standard deviation of the time change amount (2). For example, the calculation unit (121) can calculate the moving average by calculating the average of the time change amounts over a predetermined number of measurement cycles. The calculation unit (121) can calculate the standard deviation based on the difference between the moving average and the time change amount. Meanwhile, various conventionally known methods can be applied to the method of calculating the moving average and standard deviation in the calculation unit (121).

[0061] According to an embodiment, the calculation unit (121) can calculate Bollinger bands using a moving average and a standard deviation. For example, the calculation unit (121) can calculate an upper limit (1) by listing values ​​obtained by adding a certain multiple of the standard deviation to the moving average in chronological order, and can calculate a lower limit (3) by listing values ​​obtained by subtracting a certain multiple of the standard deviation from the moving average in chronological order.

[0062] The calculation unit (121) can transmit the time change amount and Bollinger band to the leak cell determination unit (122). At this time, the time change amount and Bollinger band can be calculated for each of the multiple battery cells corresponding to the leak cell detection target and transmitted to the leak cell determination unit (122).

[0063] Hereinafter, with reference to FIGS. 5 and 6, the process of calculating the time change amount (2) and the Bollinger band by the calculation unit (121) according to one embodiment of the present invention will be explained.

[0064] Referring to FIG. 5, an example of a measurement value generated by a gas sensor (110) can be seen when one of the multiple gas sensors (110) performs the operation of approaching and moving away twice with respect to one of the battery cells corresponding to the leak cell among the multiple battery cells, and referring to FIG. 6, an example of a time change amount (2) and a Bollinger band calculated by the calculation unit (121) in the above case can be seen.

[0065] First, the output unit (121) can receive a measurement value for any one battery cell corresponding to a leak cell from the gas sensor (110). For example, the output unit (121) can receive a measurement value that is maintained constant in the 0 → A section, decreases rapidly in the A → B section, increases rapidly in the B → C section, is maintained constant again in the C → D section, decreases rapidly again in the D → E section, and increases rapidly again in the E → F section, as shown in FIG. 5.

[0066] Subsequently, the calculation unit (121) can calculate the time change amount (2) using the measurement value of FIG. 5. For example, as shown in FIG. 6, the calculation unit (121) can calculate a time change amount (2) close to 0 in the 0 → A section, a negative time change amount (2) in the A → B section, and a positive time change amount (2) in the B → C section. Additionally, the calculation unit (121) can again calculate a time change amount (2) close to 0 in the C → D section, a negative time change amount (2) in the D → E section, and a positive time change amount (2) in the E → F section. That is, referring to FIGS. 5 and 6, the calculation unit (121) calculates a negative time change amount (2) in the section where the measured value decreases rapidly (A → B, D → E), and calculates a positive time change amount (2) in the section where the measured value increases rapidly (B → C, E → F).

[0067] Subsequently, the calculation unit (121) can calculate the upper limit (1) and lower limit (3) of the Bollinger band using the amount of change in time (2). For example, as shown in FIG. 6, the calculation unit (121) can calculate a Bollinger band in which the gap between the upper limit (1) and the lower limit (3) is relatively narrow because the variability of the amount of change in time (2) is relatively small in the 0 → A section, and can calculate a Bollinger band in which the gap between the upper limit (1) and the lower limit (3) is relatively wide because the amount of change in time (2) decreases and increases rapidly in the A → B → C section, that is, the variability of the amount of change in time (2) is relatively large. Additionally, the output unit (121) can calculate a Bollinger band in which the gap between the upper limit (1) and the lower limit (3) narrows as the variability of the amount of change of time (2) decreases in the C → D section, and can calculate a Bollinger band in which the gap between the upper limit (1) and the lower limit (3) widens again as the variability of the amount of change of time (2) increases again in the D → E → F section.

[0068] The leak cell determination unit (122) can receive the time change amount (2) and Bollinger bands from the calculation unit (121) at each measurement cycle. At this time, the leak cell determination unit (122) can receive each of the multiple time change amounts (2) and multiple Bollinger bands calculated for each of the multiple battery cells corresponding to the leak cell detection target.

[0069] The leak cell judgment unit (122) can generate a leak cell judgment graph by arranging the time change amount (2), the upper limit (1) and lower limit (3) of the Bollinger band in chronological order. Here, the leak cell judgment graph generated by the leak cell judgment unit (122) may have time on the x-axis and the time change amount on the y-axis. For example, the leak cell judgment unit (122) can generate the leak cell judgment graph of FIG. 6 by arranging the time change amount (2) calculated using the measurement value of FIG. 5 and the upper limit (1) and lower limit (3) of the Bollinger band in chronological order. At this time, the leak cell judgment unit (122) can generate each of the plurality of leak cell judgment graphs for each of the plurality of battery cells corresponding to the leak cell detection target.

[0070] The leak cell determination unit (122) can determine whether a battery cell is a leak cell by utilizing the relationship between the time change amount (2) included in the leak cell determination graph for a specific battery cell and the Bollinger band. At this time, the leak cell determination unit (122) can determine whether each of the multiple battery cells is a leak cell by analyzing each of the multiple leak cell determination graphs.

[0071] Referring to FIGS. 5 and 6, the section from A to B of the leak cell judgment graph corresponds to the section while the gas sensor (110) approaches the leak cell. In this section (A → B), as the gas sensor (110) approaches the leak cell, the measurement value generated by the gas sensor (110) decreases rapidly, so a section occurs where the time change amount (2) becomes lower than the lower limit (3) of the Bollinger band. At this time, a first point (P) occurs where the time change amount (2) goes down past the lower limit (3) of the Bollinger band.

[0072] Sections B through C of the leak cell judgment graph correspond to the period during which the gas sensor (110) moves away from the leak cell. In this section (B → C), as the gas sensor (110) moves away from the leak cell, the measurement value generated by the gas sensor (110) increases rapidly, so a section occurs where the time change amount (2) exceeds the upper limit (1) of the Bollinger band. At this time, a second point (Q) occurs where the time change amount (2) breaks through the upper limit (1) of the Bollinger band. This is also the case in the D→E→F section of the leak cell judgment graph.

[0073] That is, when the battery cell is a leak cell, while the gas sensor (110) moves closer to and further away from the battery cell, a section where the time change amount (2) is lower than the lower limit (3) of the Bollinger band and a section where the time change amount (2) is higher than the upper limit (1) of the Bollinger band occur on the leak cell judgment graph. Accordingly, a first point (P) where the time change amount (2) goes down past the lower limit (3) of the Bollinger band and a second point (Q) where the time change amount goes up past the upper limit (1) of the Bollinger band occur on the leak cell judgment graph.

[0074] According to an embodiment, the leak cell determination unit (122) can determine that a battery cell is a leak cell when a first point (P) occurs where the time change amount (2) goes down through the lower limit (3) of the Bollinger band and a second point (Q) occurs where the time change amount (2) goes up through the upper limit (1) of the Bollinger band on a leak cell determination graph generated for a specific battery cell.

[0075] The time change amount (2) of the measurement value generated by the gas sensor (110) and the Bollinger band represent the change amount of the measurement value in the gas sensor (110) due to a leak cell in a state where the deviation of the gas sensor (110) itself due to the characteristics of the gas sensor (110) and environmental differences is reflected. Accordingly, if the deviation of the gas sensor (110) is constant, the influence of the deviation of the gas sensor (110) on the time change amount (2) of the measurement value and the Bollinger band of the gas sensor (110) is minimized. Therefore, when detecting a leak cell using the time change amount (2) and the Bollinger band, it is possible to accurately determine whether a specific battery cell is a leak cell even if there is a deviation between gas sensors (110).

[0076] In addition, even if a temporary error occurs in some gas sensors (110), the Bollinger Bands can filter out errors caused by temporary noise because they analyze data based on the moving average and standard deviation over a certain period rather than instantaneous fluctuations.

[0077] The leak cell determination unit (122) can extract the movement section of the gas sensor (110) corresponding to the time when the gas sensor (110) approaches and moves away from the battery cell in the leak cell determination graph for a specific battery cell. At this time, the leak cell determination unit (122) can receive movement data regarding the movement of the gas sensor (110) from the storage unit (130). Here, the movement data may include information regarding the direction of movement of the gas sensor (110), the time at which movement begins, and the time at which movement stops. At this time, the leak cell determination unit (122) can extract the movement section of the gas sensor (110) for each of the plurality of leak cell determination graphs for each of the plurality of battery cells.

[0078] According to an embodiment, the leak cell determination unit (122) can extract the movement section of the gas sensor (110) from the leak cell determination graph by using the time when the movement of the gas sensor (110) included in the movement data starts and the time when the movement of the gas sensor (110) stops.

[0079] The reason for extracting the movement section of the gas sensor (110) in the leak cell judgment unit (122) is that, as illustrated in X of FIG. 6, the first point and the second point may occur on the leak cell judgment graph even though the amount of time change due to the movement of the gas sensor (110) does not rapidly increase or rapidly decrease. This occurs because the gap between the upper limit (1) and the lower limit (3) of the Bollinger band, which had widened due to the movement of the gas sensor (110) prior to stopping, narrows again as the movement of the gas sensor (110) stops, thereby narrowing the gap between the upper limit (1) and the lower limit (3) of the Bollinger band. That is, in addition to the case caused by the movement of the gas sensor (110), a change in the relationship between the amount of time change and the Bollinger band may occur during the process in which the gap between the upper limit (1) and the lower limit (3) of the Bollinger band narrows again while the movement of the gas sensor (110) is stopped. That is, by extracting the section obtained while the gas sensor (110) is moving from the leak cell judgment graph and determining whether the first point and the second point occur only for that section, the case where the first point and the second point occur while the gas sensor (110) is stopped moving can be excluded.

[0080] The leak cell determination unit (122) can determine whether the battery cell is a leak cell by determining whether the first and second points occurred in the moving section of the gas sensor (110).

[0081] FIG. 7 is a flowchart of a leak cell detection method according to one embodiment of the present invention.

[0082] Referring to FIG. 7, a leak cell detection method according to one embodiment of the present invention may include a step of calculating a time change amount and a Bollinger band (S100), a graph generation step (S200), a segment extraction step (S300), and a leak cell determination step (S400).

[0083] In the step of calculating the time change amount and Bollinger band (S100), the calculation unit (121) can calculate the time change amount and Bollinger band using the measurement value received from the gas sensor (110). Here, the measurement value is data generated by detecting the concentration of the electrolyte leaking from the battery cell, is generated by the gas sensor (110), and is inversely proportional to the concentration of the electrolyte.

[0084] According to an embodiment, the step (S100) of calculating the time change amount and Bollinger band may include receiving a measurement value at each measurement cycle and calculating the time change amount by dividing the difference between the first measurement value generated in this measurement cycle and the second measurement value generated in the previous cycle by the measurement cycle.

[0085] According to an embodiment, the step (S100) of calculating the time change amount and the Bollinger band may include the step of calculating the moving average and standard deviation of the time change amount, the step of calculating the upper limit of the Bollinger band by listing the values ​​obtained by adding a certain multiple of the standard deviation to the moving average in chronological order, and the step of calculating the lower limit of the Bollinger band by listing the values ​​obtained by subtracting a certain multiple of the standard deviation from the moving average in chronological order.

[0086] In the graph generation step (S200), the leak cell determination unit (122) can generate a leak cell determination graph for a specific battery cell by arranging the time change amount, the upper limit and the lower limit of the Bollinger band received from the calculation unit (121) in chronological order.

[0087] In the section extraction step (S300), the leak cell judgment unit (122) can extract the gas sensor (110) movement section corresponding to the time when the gas sensor (110) approaches and moves away from a specific battery cell in the leak cell judgment graph.

[0088] According to an embodiment, the section extraction step (S300) may include the step of receiving movement data of the gas sensor (110) from the storage unit (130) and the step of extracting the movement section of the gas sensor (110) from the leak cell judgment graph using the time when the movement of the gas sensor (110) starts and the time when the movement of the gas sensor (110) stops included in the movement data.

[0089] In the leak cell determination step (S400), the leak cell determination unit (122) can determine whether the battery cell is a leak cell based on whether the gas sensor (110) movement section includes a first point (P) where the amount of time change goes down past the lower limit of the Bollinger band and a second point (Q) where the amount of time change goes up past the upper limit of the Bollinger band.

[0090] According to an embodiment, the leak cell determination step (S400) may include a step of determining that the battery cell is a leak cell if the first point (P) and the second point (Q) are included in the moving section of the gas sensor (110), and a step of determining that the battery cell is not a leak cell if the first point (P) or the second point (Q) is not included in the moving section of the gas sensor (110).

[0091] Meanwhile, the above-described method can be written as a program that can be executed on a computer and can be implemented in a general-purpose digital computer that operates the program using a computer-readable recording medium. The computer-readable recording medium may include a storage medium such as a magnetic storage medium such as ROM, RAM, USB, floppy disk, or hard disk, or an optical reading medium such as a CD-ROM or DVD.

[0092] The scope of the present invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of the present invention.

Claims

1. A gas sensor that generates a measurement value that varies according to the concentration of the leaked electrolyte using a resistance value that varies according to the electrolyte leaking from the battery cell; and A control unit comprising: calculating the time change amount of the above-mentioned measurement value and the Bollinger band of the said time change amount; generating a leak cell determination graph for the said battery cell by arranging the said time change amount, the upper limit of the said Bollinger band, and the lower limit of the said Bollinger band in chronological order; and determining whether the said battery cell is a leak cell based on whether the leak cell determination graph includes a first point where the said time change amount goes down through the lower limit of the said Bollinger band and a second point where the said time change amount goes up through the upper limit of the said Bollinger band. Leak cell detection system.

2. In Paragraph 1, The above gas sensor is, Transferred to be close to the battery cell by a transfer device and then transferred to be far from the battery cell, Leak cell detection system.

3. In Paragraph 1, The above control unit is, The above measurement values ​​are received at every measurement cycle, and A calculation unit comprising calculating the time change amount by dividing the difference between the first measurement value generated in this measurement cycle and the second measurement value generated in the previous cycle by the measurement cycle. Leak cell detection system.

4. In Paragraph 1, The above control unit is, Calculate the moving average and standard deviation of the above time change amount, and A calculation unit comprising: a calculation unit that calculates the upper limit of the Bollinger Band by arranging values ​​obtained by adding a certain multiple of the standard deviation to the moving average in chronological order, and calculates the lower limit of the Bollinger Band by arranging values ​​obtained by subtracting a certain multiple of the standard deviation from the moving average in chronological order. Leak cell detection system.

5. In Paragraph 1, The above control unit is, Receive movement data of the gas sensor from the storage unit, and A leak cell determination unit comprising, using the time at which the movement of the gas sensor included in the movement data and the time at which the movement of the gas sensor stops, extracts the gas sensor movement section corresponding to the time when the gas sensor approaches and moves away from the battery cell in the leak cell determination graph. Leak cell detection system.

6. In Paragraph 5, The above control unit is, If the first point and the second point are included in the above gas sensor movement section, the battery cell is determined to be a leak cell, and A leak cell determination unit comprising determining that the battery cell is not a leak cell if the first point or the second point is not included in the gas sensor movement section, Leak cell detection system.

7. A calculation unit calculates the time change amount of the measured value and the Bollinger band of the time change amount using the measured value received from the gas sensor; A leak cell determination unit generates a leak cell determination graph for a specific battery cell by arranging the time change amount received from the calculation unit and the upper and lower limits of the Bollinger band in chronological order; The above leak cell determination unit extracts a gas sensor movement section corresponding to the time when the gas sensor approaches and moves away from a specific battery cell in the leak cell determination graph; and The leak cell determination unit comprises a step of determining whether the battery cell is a leak cell based on whether the gas sensor moving section includes a first point where the time change amount goes down through the lower limit of the Bollinger band and a second point where the time change amount goes up through the upper limit of the Bollinger band. Leak cell detection method.

8. In Paragraph 7, The step of calculating the above time change amount and Bollinger bands is, A step of receiving the above measurement value at each measurement cycle; and A step comprising calculating the time change amount by dividing the difference between the first measurement value generated in this measurement cycle and the second measurement value generated in the previous cycle by the measurement cycle. Leak cell detection method.

9. In Paragraph 7, The step of calculating the above time change amount and Bollinger bands is, A step of calculating the moving average and standard deviation of the above-mentioned time change amount; A step of calculating the upper limit of the Bollinger Band by arranging values ​​obtained by adding a certain multiple of the standard deviation to the moving average in chronological order; and A step comprising calculating the lower limit of the Bollinger Band by arranging values ​​obtained by subtracting a certain multiple of the standard deviation from the moving average in chronological order. Leak cell detection method.

10. In Paragraph 7, The step of extracting the above gas sensor movement section is, A step of receiving movement data of the gas sensor from a storage unit; and A method comprising the step of extracting the gas sensor movement section from the leak cell determination graph using the time at which the movement of the gas sensor included in the movement data and the time at which the movement of the gas sensor stops. Leak cell detection method.

11. In Paragraph 7, The step of determining whether the above is a leak cell is, A step of determining that the battery cell is a leak cell when the first point and the second point are included in the above gas sensor movement section; and A step of determining that the battery cell is not a leak cell if the first point or the second point is not included in the gas sensor movement section, Leak cell detection method.

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