Battery cell voltage measurement method and battery system

Abstract

A battery system according to one embodiment of the present invention may comprise: a plurality of battery cells electrically connected to each other; a BMIC which is connected to both ends of each of the plurality of battery cells and measures each of a plurality of cell voltages at each cell voltage measurement cycle, and which includes a terminal through which a cell balancing current for cell balancing of the plurality of battery cells flows when the cell balancing is performed; and an MCU which, when the difference between the cell voltage of a first battery cell, including a positive electrode connected to the terminal, among the plurality of cell voltages in the current cell voltage measurement cycle and the cell voltage of the first battery cell in the immediately preceding cell voltage measurement cycle is greater than or equal to a predetermined correction value, determines whether the cell balancing has ended on the basis of the cell voltage of the first battery cell in the current cell voltage measurement cycle and each of a plurality of cell voltages of each of the remaining plurality of battery cells.

Description

Battery Cell Voltage Measurement Method and Battery System

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

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0136643 filed on October 8, 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 method for accurately measuring the cell voltage of a plurality of battery cells included in a battery and a battery management system.

[0004] Batteries are an eco-friendly technology that plays a key role in various fields, such as electric vehicles and renewable energy storage. As batteries can replace existing energy systems dependent on fossil fuels, they are an important means of reducing carbon emissions and enabling cleaner and more sustainable energy use. In particular, the importance of battery technology is increasing day by day alongside the growth of electric vehicles and energy storage systems (ESS).

[0005] Cell balancing is essential for the efficient and safe use of batteries. In a battery system, multiple battery cells are connected to form a single pack; if an imbalance occurs between these cells, it can lead to performance degradation, a shortened lifespan, and, in severe cases, even safety issues. Cell balancing ensures uniform operation by minimizing differences in voltage and capacity among individual battery cells, thereby playing a crucial role in maintaining the performance and safety of the battery pack.

[0006] Accurate cell balancing requires technology that measures the voltage of battery cells very accurately. This is because even minute voltage differences between battery cells can lead to significant imbalances over the long term.

[0007] The present invention aims to provide a method and a battery management system capable of accurately measuring the cell voltage of a plurality of battery cells included in a battery.

[0008] A battery system according to one embodiment of the present invention may include a plurality of electrically connected battery cells, a BMIC connected to each end of each of the plurality of battery cells to measure each of the plurality of cell voltages at each cell voltage measurement cycle, and a first battery cell including a positive electrode connected to the terminal among the plurality of cell voltages, wherein the difference between the cell voltage in the current cell voltage measurement cycle and the cell voltage in the previous cell voltage measurement cycle is greater than or equal to a predetermined correction value, and an MCU that determines whether the cell balancing is terminated based on the cell voltage in the current cell voltage measurement cycle of the first battery cell and each of the plurality of cell voltages of the remaining plurality of battery cells.

[0009] The above correction value can be calculated by multiplying the number of battery cells among the plurality of battery cells for which cell balancing is being performed, the size of the resistance connected between the terminal and the first battery cell, and the amount of current consumed in the first battery cell when cell balancing is performed for one battery cell.

[0010] The MCU may include a cell voltage correction unit that receives each of the plurality of cell voltages from the BMIC at each cell voltage measurement cycle and determines whether correction is required for the cell voltage of the first battery cell based on a change in the magnitude of the cell voltage of the first battery cell, and a cell balancing control unit that generates a control signal to terminate the cell balancing and transmits it to the BMIC according to the result of determining whether the cell balancing is terminated.

[0011] The MCU can generate a first cell voltage of the first battery cell by adding the correction value to the cell voltage of the first battery cell in the current cell voltage measurement cycle when the difference between the cell voltage of the first battery cell in the current cell voltage measurement cycle and the cell voltage of the previous cell voltage measurement cycle is less than the correction value, and determine whether to terminate the cell balancing based on the first cell voltage and each of the multiple cell voltages of the remaining multiple battery cells.

[0012] The MCU can generate a first cell voltage of the first battery cell by adding the correction value to the cell voltage of the first battery cell in the current cell voltage measurement cycle when the difference between the cell voltage in the previous cell voltage measurement cycle of the first battery cell and the cell voltage in the current cell voltage measurement cycle is greater than or equal to the correction value, and determine whether to terminate the cell balancing based on the first cell voltage and each of the plurality of cell voltages of the remaining plurality of battery cells.

[0013] The MCU can determine whether to terminate cell balancing based on the cell voltage of the first battery cell in the current cell voltage measurement cycle and each of the multiple cell voltages of the remaining multiple battery cells when the difference between the cell voltage in the previous cell voltage measurement cycle of the first battery cell and the cell voltage in the current cell voltage measurement cycle is less than the correction value.

[0014] A battery cell voltage measurement method according to one embodiment of the present invention may include: a step in which a BMIC performs cell balancing for at least one battery cell among a plurality of battery cells included in a battery; a step in which the BMIC measures each of a plurality of cell voltages of each of the plurality of battery cells while the cell balancing is being performed; a step in which an MCU corrects the cell voltage of a first battery cell, including a positive electrode connected to a terminal through which a cell balancing current flows, among the plurality of cell voltages received from the BMIC, by adding a predetermined correction value to the cell voltage of the first battery cell; and a step in which the MCU determines whether the cell balancing is terminated based on the corrected cell voltage of the first battery cell and each of the plurality of cell voltages of each of the remaining plurality of battery cells.

[0015] The step of correcting the cell voltage of the first battery cell may include: a step in which, if the difference between the cell voltage of the first battery cell in the current cell voltage measurement cycle and the cell voltage of the previous cell voltage measurement cycle is greater than or equal to the correction value, the cell voltage of the first battery cell in the current cell voltage measurement cycle and each of the multiple cell voltages of each of the remaining multiple battery cells are transmitted to the cell balancing control unit of the MCU without correcting the cell voltage of the first battery cell in the current cell voltage measurement cycle; and if the difference between the cell voltage of the first battery cell in the current cell voltage measurement cycle and the cell voltage of the previous cell voltage measurement cycle is less than the correction value, the correction value is added to the cell voltage of the first battery cell in the current cell voltage measurement cycle to generate a first voltage of the first battery cell, and each of the first cell voltage and each of the multiple cell voltages of the remaining multiple battery cells are transmitted to the cell balancing control unit.

[0016] The step of transmitting the cell voltage of the first battery cell in the current cell voltage measurement cycle and each of the plurality of cell voltages of each of the remaining plurality of battery cells to the cell balancing control unit of the MCU may include: the step of the cell voltage correction unit, when the difference between the cell voltage in the previous cell voltage measurement cycle of the first battery cell and the cell voltage in the current cell voltage measurement cycle is greater than or equal to the correction value, adding the correction value to the cell voltage in the current cell voltage measurement cycle of the first battery cell to generate the first cell voltage of the first battery cell and transmitting each of the first cell voltage and each of the plurality of cell voltages of each of the remaining plurality of battery cells to the cell balancing control unit; and when the difference between the cell voltage in the previous cell voltage measurement cycle of the first battery cell and the cell voltage in the current cell voltage measurement cycle is less than the correction value, transmitting each of the cell voltage in the current cell voltage measurement cycle of the first battery cell and each of the plurality of cell voltages of each of the remaining plurality of battery cells to the cell balancing control unit of the MCU without correction of the cell voltage in the current cell voltage measurement cycle of the first battery cell.

[0017] The step of determining whether the cell balancing is terminated may include: a step of determining whether the cell balancing is terminated based on the cell voltage of the first battery cell in the current cell voltage measurement cycle and each of the multiple cell voltages of each of the remaining multiple battery cells when the difference between the cell voltage of the first battery cell in the current cell voltage measurement cycle and the cell voltage of the previous cell voltage measurement cycle is greater than or equal to the correction value in the step of correcting the cell voltage of the first battery cell; and a step of determining whether the cell balancing is terminated based on the first cell voltage and each of the multiple cell voltages of each of the remaining multiple battery cells when the difference between the cell voltage of the first battery cell in the current cell voltage measurement cycle and the cell voltage of the previous cell voltage measurement cycle is less than the correction value in the step of correcting the cell voltage of the first battery cell.

[0018] According to one embodiment of the present invention, the cell voltage of each of a plurality of battery cells can be accurately measured regardless of cell balancing, COV (Charge over voltage) control, and CUV (Charge under voltage) control of the BMIC.

[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 battery system according to one embodiment of the present invention.

[0021] FIG. 2 is a flowchart of a battery cell voltage measurement method according to one embodiment of the present invention.

[0022] FIG. 3 is a flowchart of the cell voltage correction step of a first battery cell according to one embodiment of the present invention.

[0023] 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 the drawings include all modifications, equivalents, and substitutions that fall within the spirit and technical scope of the invention.

[0024] 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.

[0025] When it is stated that a component is connected to or coupled with another component, it should be understood that while it may be directly connected or coupled to that other component, there may also be other components in between. Conversely, when it is stated that a component is directly connected to or directly coupled with another component, it should be understood that there are no other components in between.

[0026] 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.

[0027] The present invention will be described in detail below with reference to the attached drawings.

[0028] FIG. 1 is a block diagram of a battery system according to one embodiment of the present invention.

[0029] Referring to FIG. 1, a battery system according to one embodiment of the present invention may include a battery (10) and a battery management system (20).

[0030] The battery (10) is configured to supply power and may be a secondary battery capable of charging and discharging. The battery (10) may be a plurality of battery cells (Cell: Cell1~Cell) electrically connected in series and / or parallel. nIt may include ). Although FIG. 1 is illustrated as a plurality of battery cells connected in series constituting a single battery (10), the configuration and structure included in the battery (10) are not limited thereto. For example, the battery (10) may include a plurality of battery modules, each comprising a plurality of battery cells connected in series. At this time, the number of battery modules and battery cells included in the battery (10) can be determined in various ways depending on the choice.

[0031] A battery management system (20) (BMS) can be electrically connected to the battery (10) as a configuration for monitoring and controlling the battery (10). For example, the BMS (20) can obtain status information for a plurality of battery cells by measuring or predicting the status of a plurality of battery cells included in the battery (10), and can control the plurality of battery cells using the status information for the plurality of battery cells. The BMS (20) may include a BMIC (100) and an MCU (200).

[0032] The BMIC (100) can measure the voltage, temperature, current, etc. of multiple battery cells and can transmit the measured status information of multiple battery cells to the MCU (200).

[0033] The BMIC (100) can be electrically connected to a plurality of battery cells (Cell) included in the battery (10). For example, as shown in FIG. 1, the BMIC (100) can be electrically connected to the first battery cell (Cell1) through the nth battery cell (Cell n All battery cells (Cell1~ Cell) up to ) n The positive terminals of ) and the nth battery cell (Cell nIt can be electrically connected to the negative terminal of the battery. The BMIC (100) can receive the positive potential and negative potential of each of the multiple battery cells included in the battery (10), and can measure the cell voltage of each of the multiple battery cells by calculating the difference between the positive potential and negative potential of each of the multiple battery cells.

[0034] The BMIC (100) can receive a signal from the MCU (200) to control cell balancing and can control cell balancing for a plurality of battery cells. Here, cell balancing refers to the process of controlling a plurality of battery cells to maintain the same voltage and state of charge (SOC).

[0035] The BMIC (100) may include a terminal (N) through which a cell balancing current flows when cell balancing is performed for a plurality of battery cells. For example, as shown in FIG. 1, when cell balancing is performed for at least one of a plurality of battery cells in the BMIC (100), a cell balancing current for cell balancing may flow through a terminal (N) connected to the positive terminal of the first battery cell (Cell1). At this time, a resistor (R) may be connected between the positive terminal of the first battery cell (Cell1) and the terminal (N) of the BMIC (100).

[0036] According to an embodiment, the BMIC (100) may include a cell voltage measuring unit (110), a cell balancing circuit (120), and a COV and CUV control unit (130).

[0037] The cell voltage measuring unit (110) is connected to both ends of each of the multiple cell voltages of each of the multiple battery cells, and can measure the multiple cell voltages at each cell voltage measuring cycle. According to an embodiment, the cell voltage measuring unit (110) can measure each of the multiple cell voltages of each of the multiple battery cells at each cell voltage measuring cycle when cell balancing is performed for the multiple battery cells. The cell voltage measuring unit (110) can transmit the measured multiple cell voltages to the COV and CUV control unit (130) and MCU (200) at each cell voltage measuring cycle.

[0038] The cell balancing circuit (120) can receive a signal from the MCU (200) to control cell balancing. The cell balancing circuit (120) can perform, maintain, and terminate cell balancing in response to the control signal received from the MCU (200).

[0039] When cell balancing is performed on at least one of the plurality of battery cells in the cell balancing circuit (120), a cell balancing current for cell balancing may flow through a specific terminal (N) of the BMIC (100).

[0040] At this time, the BMIC (100) consumes the current of the battery cell (Cell) containing the positive electrode connected to the terminal (N) through which the cell balancing current flows. Accordingly, an error occurs in the measurement of the cell voltage of the battery cell (Cell) containing the positive electrode connected to the terminal (N) through which the cell balancing current flows. Meanwhile, the cell balancing control of the MCU (200) is performed based on the cell voltage measured by the BMIC (100). Therefore, for accurate cell balancing control, correction of the cell voltage of the battery cell (Cell) containing the positive electrode connected to the terminal (N) through which the cell balancing current flows is required. Regarding the correction of the cell voltage of the battery cell (Cell) containing the positive electrode connected to the terminal (N) through which the cell balancing current flows, the configuration of the cell voltage correction unit (210) of the MCU (200) will be explained in detail below.

[0041] The COV and CUV control unit (130) can perform COV (Charge Over Voltage) control when the voltage of one or more of the plurality of battery cells exceeds a preset maximum allowable voltage. For example, the COV and CUV control unit (130) can control the charging and discharging of the plurality of battery cells to be temporarily suspended when the voltage of any one of the plurality of battery cells exceeds a preset maximum allowable voltage. Through this, the COV and CUV control unit (130) can prevent overcharging of the battery (10).

[0042] The COV and CUV control unit (130) can perform CUV (Charge Under Voltage) control when the voltage of one or more of the plurality of battery cells falls below a preset minimum allowable voltage. For example, the COV and CUV control unit (130) can control the charging and discharging of the plurality of battery cells to be temporarily suspended when the voltage of any one of the plurality of battery cells falls below a preset minimum allowable voltage. Through this, the COV and CUV control unit (130) can prevent over-discharge of the battery (10).

[0043] Since the COV control or CUV control of the COV and CUV control unit (130) temporarily suspends the charging and discharging of multiple battery cells, the cell balancing being performed by the cell balancing circuit (120) may be temporarily suspended by the COV control or CUV control. The suspension of cell balancing by the COV and CUV control unit (130) is executed prior to the cell balancing control signal received by the cell balancing circuit (120) from the MCU (200), and is executed regardless of the control of the MCU (200). Therefore, the MCU (200) cannot know whether the cell balancing of the cell balancing circuit (120) has been suspended by the COV control or CUV control of the COV and CUV control unit (130).

[0044] The MCU (200) can control the charging and discharging of the battery (10) based on the status information of a plurality of battery cells received from the BMIC (100), and can execute a control algorithm to optimize the performance of the battery (10).

[0045] According to an embodiment, the MCU (200) may include a cell voltage correction unit (210) and a cell balancing control unit (220).

[0046] The cell voltage correction unit (210) can receive each of the multiple cell voltages of each of the multiple battery cells from the BMIC (100) at each cell voltage measurement cycle.

[0047] The cell voltage correction unit (210) can correct the cell voltage of the first battery cell (Cell1) among a plurality of cell voltages. Here, the first battery cell (Cell1) refers to a battery cell including a positive electrode connected to the terminal (N) through which the cell balancing current of the BMIC (100) flows.

[0048] The reason for correcting the cell voltage of the first battery cell (Cell1) in the cell voltage correction unit (210) is that when cell balancing is performed on at least one of the plurality of battery cells (Cell) by the cell balancing circuit (120), the current of the first battery cell (Cell1), which includes a positive electrode connected to the terminal (N) through which the cell balancing current flows in the BMIC (100), is consumed, and as a result, a voltage drop phenomenon occurs in the cell voltage of the first battery cell (Cell1).

[0049] The cell voltage correction unit (210) can correct the cell voltage of the first battery cell (Cell1) by adding a predetermined correction value to the cell voltage of the first battery cell (Cell1). According to an embodiment, the cell voltage correction unit (210) can generate a first cell voltage of the first battery cell (Cell1) by adding a predetermined correction value to the cell voltage of the first battery cell (Cell1). At this time, the first cell voltage refers to the value obtained by adding a predetermined correction value to the cell voltage of the first battery cell (Cell1) in this cell voltage measurement cycle.

[0050] Here, the correction value can be calculated by multiplying the number of battery cells undergoing cell balancing among multiple battery cells, the size of the resistor (R) connected between the terminal (N) of the BMIC (100) and the first battery cell (Cell1), and the amount of current consumed in the first battery cell (Cell1) when cell balancing is performed for one battery cell. At this time, the size of the resistor (R) connected between the terminal (N) of the BMIC (100) and the first battery cell (Cell1) used to calculate the correction value, and the amount of current consumed in the first battery cell (Cell1) when cell balancing is performed for one battery cell, may be set differently depending on the characteristics of the BMIC (100), and may be set at the time of design of the BMS (20) and stored in the memory of the MCU (200) (not shown in the drawing).

[0051] For example, in the battery system of FIG. 1, a plurality of battery cells (Cell-1 to Cell n ) among the first battery cell (Cell1), the second battery cell (Cell2) and the nth battery cell (Cell n Assuming that cell balancing is being performed for ) and that the resistance (R) connected between the positive terminal and the terminal (N) of the first battery cell (Cell1) is 2kΩ and the amount of current consumed by the BMIC when performing cell balancing operation for one battery cell is 35uA, in the above example, the correction value can be calculated as 0.21V, which is the value obtained by multiplying the number of battery cells (3) for which cell balancing is being performed, the size of the resistance (2kΩ), and the amount of current consumed per battery cell (35uA).

[0052] The cell voltage correction unit (210) can determine whether correction is required for the cell voltage of the first battery cell (Cell1) based on the change in magnitude of the cell voltage of the first battery cell (Cell1). At this time, the cell voltage correction unit (210) can calculate the change in magnitude of the cell voltage of the first battery cell (Cell1) by comparing the cell voltage in the current cell voltage measurement cycle with the cell voltage in the previous cell voltage measurement cycle.

[0053] The reason the cell voltage correction unit (210) determines whether correction is necessary for the cell voltage of the first battery cell (Cell1) is because when COV control or CUV control is performed by the COV and CUV control unit (130), the cell balancing being performed by the cell balancing circuit (120) is temporarily suspended. When cell balancing is temporarily suspended by COV control or CUV control, the current consumption of the first battery cell (Cell1) by the BMIC (100) is also temporarily suspended, and the voltage drop phenomenon occurring in the cell voltage of the first battery cell (Cell1) is not occurring for a while, so there is no need to correct the measurement error caused by the voltage drop in the cell voltage of the first battery cell (Cell1) caused by cell balancing.

[0054] Meanwhile, the amount of change in cell voltage of the first battery cell (Cell1) due to the interruption or resumption of cell balancing by COV control or CUV control changes rapidly in a relatively short period of time, so it is distinguished from the amount of change in cell voltage of the first battery cell (Cell1) that occurs during cell balancing, which changes slowly over a relatively long period of time. Therefore, when cell balancing being performed in the cell balancing circuit (120) by the COV and CUV control unit (130) is temporarily interrupted, the correction of the cell voltage of the first battery cell (Cell1) by the cell voltage correction unit (210) is no longer necessary, so the cell voltage correction unit (210) can determine whether correction of the cell voltage of the first battery cell (Cell1) is necessary based on the change in magnitude of the cell voltage of the first battery cell (Cell1).

[0055] According to an embodiment, the cell voltage correction unit (210) can determine whether correction is required for the cell voltage of the first battery cell (Cell1) based on the difference between the cell voltage in the current cell voltage measurement cycle and the cell voltage in the previous cell voltage measurement cycle. This is because when COV control or CUV control by the COV and CUV control unit (130) starts, cell balancing is temporarily suspended and the magnitude of the cell voltage of the first battery cell (Cell1) increases instantaneously.

[0056] For example, the cell voltage correction unit (210) may determine that no correction is required for the cell voltage of the first battery cell (Cell1) if the difference between the cell voltage of the first battery cell (Cell1) in the current cell voltage measurement cycle and the cell voltage of the previous cell voltage measurement cycle is greater than or equal to a predetermined correction value. At this time, the cell voltage correction unit (210) may transmit the cell voltage of the first battery cell (Cell1) in the current cell voltage measurement cycle and each of the multiple cell voltages of each of the remaining multiple battery cells to the cell balancing control unit (220) without correction for the cell voltage of the first battery cell (Cell1) in the current cell voltage measurement cycle.

[0057] As another example, the cell voltage correction unit (210) may determine that correction is required for the cell voltage of the first battery cell (Cell1) when the difference between the cell voltage in the current cell voltage measurement cycle of the first battery cell (Cell1) and the cell voltage in the previous cell voltage measurement cycle is less than a predetermined correction value. At this time, the cell voltage correction unit (210) may generate the first cell voltage of the first battery cell (Cell1) by adding a predetermined correction value to the cell voltage in the current cell voltage measurement cycle of the first battery cell (Cell1), and transmit the first cell voltage and each of the multiple cell voltages of each of the remaining multiple battery cells to the cell balancing control unit (220).

[0058] According to an embodiment, the cell voltage correction unit (210) can determine whether correction is required for the cell voltage of the first battery cell (Cell1) based on the difference between the cell voltage in the previous cell voltage measurement cycle of the first battery cell (Cell1) and the cell voltage in the current cell voltage measurement cycle. This is because when COV control or CUV control by the COV and CUV control unit (130) is stopped, cell balancing is restarted and the magnitude of the cell voltage of the first battery cell (Cell1) is instantaneously reduced.

[0059] For example, the cell voltage correction unit (210) may determine that correction is required for the cell voltage of the first battery cell (Cell1) when the difference between the cell voltage in the previous cell voltage measurement cycle of the first battery cell (Cell1) and the cell voltage in the current cell voltage measurement cycle is greater than or equal to a predetermined correction value. At this time, the cell voltage correction unit (210) may generate the first cell voltage of the first battery cell (Cell1) by adding a predetermined correction value to the cell voltage in the current cell voltage measurement cycle of the first battery cell (Cell1), and transmit the first cell voltage and each of the multiple cell voltages of each of the remaining multiple battery cells to the cell balancing control unit (220).

[0060] As another example, the cell voltage correction unit (210) may determine that no correction is required for the cell voltage of the first battery cell (Cell1) when the difference between the cell voltage in the previous cell voltage measurement cycle of the first battery cell (Cell1) and the cell voltage in the current cell voltage measurement cycle is less than a predetermined correction value. In this case, the cell voltage correction unit (210) may transmit the cell voltage of the first battery cell (Cell1) in the current cell voltage measurement cycle and each of the multiple cell voltages of each of the remaining multiple battery cells to the cell balancing control unit (220) without correction for the cell voltage of the first battery cell (Cell1) in the current cell voltage measurement cycle.

[0061] The cell balancing control unit (220) can receive the cell voltage of the first battery cell (Cell1) and each of the multiple cell voltages of each of the remaining multiple battery cells from the cell voltage correction unit (210). At this time, the cell voltage of the first battery cell (Cell1) received by the cell balancing control unit (220) from the cell voltage correction unit (210) may be the cell voltage of the first battery cell (Cell1) in this cell voltage measurement cycle, or the first cell voltage generated by adding a predetermined correction value to the cell voltage of this cell voltage measurement cycle.

[0062] The cell balancing control unit (220) can determine whether to terminate cell balancing for the plurality of battery cells (Cell) based on the cell voltage of the first battery cell (Cell1) and each of the plurality of cell voltages of each of the remaining plurality of battery cells.

[0063] The cell balancing control unit (220) can generate a control signal to maintain cell balancing or a control signal to terminate cell balancing based on the result of determining whether to terminate cell balancing for a plurality of battery cells (Cell) and transmit it to the BMIC (100).

[0064] FIG. 2 is a flowchart of a battery cell voltage measurement method according to one embodiment of the present invention.

[0065] Referring to FIG. 2, a battery cell voltage measurement method according to one embodiment of the present invention may include a cell balancing execution step (S100), a cell voltage measurement step (S200), a cell voltage correction step of a first battery cell (S300), and a step of determining whether to end cell balancing (S400).

[0066] In the cell balancing execution step (S100), the BMIC (100) can perform cell balancing on at least one of the plurality of battery cells (Cell) included in the battery (10).

[0067] In the cell voltage measurement step (S200), the BMIC (100) can measure each of the multiple cell voltages of each of the multiple battery cells while cell balancing is being performed. At this time, the cell voltage measurement unit (110) of the BMIC (100) can transmit each of the multiple cell voltages to the COV and CUV control unit (130) and the MCU (200).

[0068] In the cell voltage correction step (S300) of the first battery cell, the MCU (200) can correct the cell voltage of the first battery cell (Cell1) among a plurality of cell voltages. At this time, the MCU (200) can correct the cell voltage of the first battery cell (Cell1) by adding a predetermined correction value to the cell voltage of the first battery cell (Cell1) which includes a positive electrode connected to a terminal (N) through which cell balancing current flows, which is included in the BMIC (100).

[0069] In the cell balancing termination determination step (S400), the MCU (200) can determine whether cell balancing is terminated based on the cell voltage of the corrected first battery cell (Cell1) and each of the multiple cell voltages of each of the remaining multiple battery cells.

[0070] According to an embodiment, the MCU (200) can determine whether the cell balancing being performed in the BMIC (100) is sufficient based on the cell voltage of the corrected first battery cell (Cell1) and the remaining second cell voltage. If the MCU (200) determines that the cell balancing is sufficient, it can generate a control signal to terminate the cell balancing and transmit it to the BMIC (100); if it determines that the cell balancing is not sufficient, it can generate a control signal to maintain the cell balancing and transmit it to the BMIC (100). At this time, the BMIC (100) can terminate or maintain the cell balancing in response to the control signal of the MCU (200).

[0071] FIG. 3 is a flowchart of the cell voltage correction step (S300) of the first battery cell according to one embodiment of the present invention.

[0072] Referring to FIG. 3, in the cell voltage correction step (S300) of the first battery cell according to one embodiment of the present invention, the MCU (200) can determine whether correction of the cell voltage of the first battery cell (Cell1) is necessary based on the magnitude change of the cell voltage of the first battery cell (Cell1).

[0073] In the cell voltage correction step (S300) of the first battery cell, the cell voltage correction unit (210) of the MCU (200) can determine whether correction is required for the cell voltage of the first battery cell (Cell1) based on the difference between the cell voltage in the current cell voltage measurement cycle and the cell voltage in the previous cell voltage measurement cycle (S310, S321, S322).

[0074] According to an embodiment, in the cell voltage correction step (S300) of the first battery cell, the cell voltage correction unit (210) can determine whether the difference between the cell voltage in the current cell voltage measurement cycle and the cell voltage in the previous cell voltage measurement cycle of the first battery cell (Cell1) is greater than or equal to a predetermined correction value (S310).

[0075] According to an embodiment, in the cell voltage correction step (S300) of the first battery cell, if the difference between the cell voltage of the first battery cell (Cell1) in the current cell voltage measurement cycle and the cell voltage in the previous cell voltage measurement cycle is greater than or equal to a predetermined correction value (S310, Y), the cell voltage of the first battery cell (Cell1) in the current cell voltage measurement cycle and each of the multiple cell voltages of each of the remaining multiple battery cells can be transmitted to the cell balancing control unit (220) of the MCU (200) without correction of the cell voltage of the first battery cell (Cell1) in the current cell voltage measurement cycle (S321). At this time, the cell balancing control unit (220) can determine whether to terminate cell balancing based on the cell voltage of the first battery cell (Cell1) in the current cell voltage measurement cycle and each of the multiple cell voltages of each of the remaining multiple battery cells.

[0076] According to an embodiment, in the cell voltage correction step (S300) of the first battery cell, if the difference between the cell voltage of the first battery cell (Cell1) in the current cell voltage measurement cycle and the cell voltage in the previous cell voltage measurement cycle is less than a predetermined correction value (S310, N), the cell voltage correction unit (210) can generate the first cell voltage of the first battery cell (Cell1) by adding a predetermined correction value to the cell voltage of the first battery cell (Cell1) in the current cell voltage measurement cycle, and transmit the first cell voltage and each of the plurality of cell voltages of each of the remaining plurality of battery cells to the cell balancing control unit (220) (S322). At this time, the cell balancing control unit (220) can determine whether to terminate cell balancing based on the first cell voltage and each of the plurality of cell voltages of each of the remaining plurality of battery cells.

[0077] In the cell voltage correction step (S300) of the first battery cell, the cell voltage correction unit (210) of the MCU (200) can determine whether correction is required for the cell voltage of the first battery cell (Cell1) based on the difference between the cell voltage in the previous cell voltage measurement cycle and the cell voltage in the current cell voltage measurement cycle (S330, S341, S342).

[0078] According to the embodiment, in the cell voltage correction step (S300) of the first battery cell, the cell voltage correction unit (210) can determine whether the difference between the cell voltage in the previous cell voltage measurement cycle and the cell voltage in the current cell voltage measurement cycle of the first battery cell (Cell1) is greater than or equal to a predetermined correction value (S330).

[0079] According to an embodiment, in the cell voltage correction step (S300) of the first battery cell, if the difference between the cell voltage in the previous cell voltage measurement cycle of the first battery cell (Cell1) and the cell voltage in the current cell voltage measurement cycle is greater than or equal to a predetermined correction value (S330, Y), the cell voltage correction unit (210) can generate the first cell voltage of the first battery cell (Cell1) by adding a predetermined correction value to the cell voltage in the current cell voltage measurement cycle of the first battery cell (Cell1), and transmit the first cell voltage and each of the plurality of cell voltages of each of the remaining plurality of battery cells to the cell balancing control unit (220) (S341). At this time, the cell balancing control unit (220) can determine whether to terminate cell balancing based on the first cell voltage and each of the plurality of cell voltages of each of the remaining plurality of battery cells.

[0080] According to an embodiment, in the cell voltage correction step (S300) of the first battery cell, if the difference between the cell voltage in the previous cell voltage measurement cycle of the first battery cell (Cell1) and the cell voltage in the current cell voltage measurement cycle is less than a predetermined correction value (S330, N), the cell voltage in the current cell voltage measurement cycle of the first battery cell (Cell1) and each of the plurality of cell voltages of each of the remaining plurality of battery cells can be transmitted to the cell balancing control unit (220) without correction of the cell voltage in the current cell voltage measurement cycle of the first battery cell (Cell1) (S342). At this time, the cell balancing control unit (220) can determine whether to terminate cell balancing based on the cell voltage in the current cell voltage measurement cycle of the first battery cell (Cell1) and each of the plurality of cell voltages of each of the remaining plurality of battery cells.

[0081] According to the embodiment, the cell voltage correction step (S300) of the first battery cell may be performed repeatedly until cell balancing is terminated in the cell balancing termination determination step (S400).

[0082] 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.

[0083] 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. Multiple electrically connected battery cells; When cell balancing is performed on the plurality of battery cells, a BMIC including a terminal through which a cell balancing current for the cell balancing flows, and connected to both ends of each of the plurality of battery cells to measure each of the plurality of cell voltages at each cell voltage measurement cycle; and A MCU comprising, when the difference between the cell voltage in the current cell voltage measurement cycle and the cell voltage in the previous cell voltage measurement cycle of the first battery cell including the positive electrode connected to the terminal among the plurality of cell voltages is greater than or equal to a predetermined correction value, the MCU determining whether to terminate the cell balancing based on the cell voltage in the current cell voltage measurement cycle of the first battery cell and each of the plurality of cell voltages of each of the remaining plurality of battery cells. Battery system.

2. In Paragraph 1, The above correction value is, Calculated by multiplying the number of battery cells among the plurality of battery cells for which cell balancing is being performed, the size of the resistance connected between the terminal and the first battery cell, and the amount of current consumed in the first battery cell when cell balancing is performed for one battery cell, Battery system.

3. In Paragraph 1, The above MCU is, A cell voltage correction unit that receives each of the plurality of cell voltages from the BMIC at each cell voltage measurement cycle and determines whether correction is required for the cell voltage of the first battery cell based on a change in the magnitude of the cell voltage of the first battery cell; and A cell balancing control unit comprising, based on a determination result regarding whether the cell balancing is terminated, a control signal for terminating the cell balancing and transmitting it to the BMIC. Battery system.

4. In Paragraph 1, The above MCU is, When the difference between the cell voltage of the first battery cell in the current cell voltage measurement cycle and the cell voltage in the previous cell voltage measurement cycle is less than the correction value, the correction value is added to the cell voltage of the first battery cell in the current cell voltage measurement cycle to generate the first cell voltage of the first battery cell, and the cell balancing is determined based on the first cell voltage and each of the plurality of cell voltages of the remaining plurality of battery cells. Battery system.

5. In Paragraph 1, The above MCU is, When the difference between the cell voltage in the previous cell voltage measurement cycle of the first battery cell and the cell voltage in the current cell voltage measurement cycle is greater than or equal to the correction value, the correction value is added to the cell voltage in the current cell voltage measurement cycle of the first battery cell to generate the first cell voltage of the first battery cell, and the cell balancing is determined based on the first cell voltage and each of the plurality of cell voltages of the remaining plurality of battery cells. Battery system.

6. In Paragraph 1, The above MCU is, When the difference between the cell voltage in the previous cell voltage measurement cycle of the first battery cell and the cell voltage in the current cell voltage measurement cycle is less than the correction value, determining whether to terminate the cell balancing based on the cell voltage in the current cell voltage measurement cycle of the first battery cell and each of the plurality of cell voltages of each of the remaining plurality of battery cells. Battery system.

7. A step in which the BMIC performs cell balancing on at least one battery cell among a plurality of battery cells included in the battery; The above BMIC measures each of the plurality of cell voltages of each of the plurality of battery cells while the cell balancing is being performed; The MCU corrects the cell voltage of a first battery cell, which includes a positive electrode connected to a terminal through which a cell balancing current flows, among the plurality of cell voltages received from the BMIC, by adding a predetermined correction value to the cell voltage of the first battery cell; and The above MCU includes a step of determining whether to terminate the cell balancing based on the cell voltage of the corrected first battery cell and each of the plurality of cell voltages of each of the remaining plurality of battery cells. Battery cell voltage measurement method.

8. In Paragraph 7, The step of correcting the cell voltage of the first battery cell is, A step in which, if the difference between the cell voltage of the first battery cell in the current cell voltage measurement cycle and the cell voltage in the previous cell voltage measurement cycle is greater than or equal to the correction value, the cell voltage of the first battery cell in the current cell voltage measurement cycle and each of the plurality of cell voltages of each of the remaining plurality of battery cells are transmitted to the cell balancing control unit of the MCU without correction of the cell voltage of the first battery cell in the current cell voltage measurement cycle; and If the difference between the cell voltage of the first battery cell in the current cell voltage measurement cycle and the cell voltage in the previous cell voltage measurement cycle is less than the correction value, the correction value is added to the cell voltage of the first battery cell in the current cell voltage measurement cycle to generate a first voltage of the first battery cell, and each of the first cell voltage and the plurality of cell voltages of each of the remaining plurality of battery cells is transmitted to the cell balancing control unit. Battery cell voltage measurement method.

9. In Paragraph 8, The step of transmitting the cell voltage of the first battery cell in this cell voltage measurement cycle and each of the plurality of cell voltages of each of the remaining plurality of battery cells to the cell balancing control unit of the MCU is: The cell voltage correction unit, when the difference between the cell voltage in the previous cell voltage measurement cycle of the first battery cell and the cell voltage in the current cell voltage measurement cycle is greater than or equal to the correction value, adds the correction value to the cell voltage in the current cell voltage measurement cycle of the first battery cell to generate a first cell voltage of the first battery cell, and transmits the first cell voltage and each of the plurality of cell voltages of each of the remaining plurality of battery cells to the cell balancing control unit; and If the difference between the cell voltage in the previous cell voltage measurement cycle of the first battery cell and the cell voltage in the current cell voltage measurement cycle is less than the correction value, the method comprises the step of transmitting the cell voltage in the current cell voltage measurement cycle of the first battery cell and each of the plurality of cell voltages of each of the remaining plurality of battery cells to the cell balancing control unit of the MCU without correction for the cell voltage in the current cell voltage measurement cycle of the first battery cell. Battery cell voltage measurement method.

10. In Paragraph 8, The step of determining whether the above cell balancing is terminated is, In the step of correcting the cell voltage of the first battery cell, if the difference between the cell voltage of the first battery cell in the current cell voltage measurement cycle and the cell voltage in the previous cell voltage measurement cycle is greater than or equal to the correction value, the step of determining whether to terminate the cell balancing based on the cell voltage of the first battery cell in the current cell voltage measurement cycle and each of the plurality of cell voltages of each of the remaining plurality of battery cells; and A step of correcting the cell voltage of the first battery cell, wherein if the difference between the cell voltage of the first battery cell in the current cell voltage measurement cycle and the cell voltage in the previous cell voltage measurement cycle is less than the correction value, a step of determining whether to terminate the cell balancing based on the first cell voltage and each of the plurality of cell voltages of each of the remaining plurality of battery cells. Battery cell voltage measurement method.

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