Battery management system, battery pack having the same, and method for detecting poor contact module using the same

Abstract

To provide, in relation to a battery management system and a battery pack having the same, the battery management system capable of detecting a poor contact module using a cell balancer, and to provide the battery pack having the same.SOLUTION: A battery management system includes: a plurality of slave management units arranged to correspond to a plurality of battery modules, respectively, and perform a balancing operation to uniformly adjust cell voltages of a plurality of battery cells that constitute a battery module; a master management unit for detecting a defective module that is a battery module having a poor contact inside using a voltage deviation being a difference between a maximum value and a minimum value of cell voltages; and a data transfer unit for electrically connecting the master management unit and the slave management unit to each other to exchange data.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a battery management system, a battery pack including the same, and a method for detecting a poorly contacted module using the same, and more particularly to a battery management system capable of detecting a poorly contacted module in a battery pack, a battery pack including the same, and a method for detecting a poorly contacted module using the same. [Background technology]

[0002] 2. Description of the Related Art In order to use secondary batteries as a power source for vehicles and industrial equipment, battery packs in which a large number of battery modules each consisting of a large number of secondary battery cells are connected together are widely used.

[0003] The overall capacity of a battery pack is affected not only by the capacity of each unit module but also by voltage imbalance between the battery cells. For example, even if some battery modules in a battery pack have sufficient charge capacity, if other battery modules are discharging, the entire battery pack may be discharged.

[0004] Generally, voltage imbalance in a battery pack occurs due to normal discharge caused by normal use of the battery module and resistive discharge caused by poor contact within the battery module.

[0005] Normal discharge is battery discharge that occurs during normal use of the battery pack. While the battery pack is operating, the degree of deterioration of each battery cell constituting a battery module varies depending on the inherent process characteristics of the battery cells, the operating environment, and the operating conditions applied to each battery cell, resulting in voltage deviations between each battery cell and between each battery module made up of battery cells.

[0006] Therefore, as the usage time of the battery pack increases, the individual battery modules are normally discharged, which causes voltage imbalance between the battery modules, resulting in a decrease in performance.

[0007] In contrast, resistive discharge is battery discharge that occurs not from the battery cell but from a locally generated fault point due to poor contact within the battery module.

[0008] Defective points frequently occur due to poor contact such as disconnection during the manufacturing process of a battery module, or due to foreign matter entering the battery or external forces such as vibration during use of the manufactured battery module. The defective points act as current leakage paths, and a battery module with a defective point, which is a poorly contacted module, has a relatively low charging voltage, causing a voltage imbalance.

[0009] In this case, voltage imbalance of individual battery modules due to normal discharge can be detected using a battery management system (BMS), and can be easily improved by cell balancing.

[0010] However, to detect voltage imbalance due to resistive discharge, the battery pack is disassembled into individual battery modules, and then an open circuit voltage-internal resistance (OCV-IR) test device is used to detect poor contact in the battery modules.

[0011] In particular, disassembling a battery pack requires a lot of time and money because it interrupts the operation of the vehicle or industrial machine equipped with the battery pack and requires reinstallation after removing the loose contact module.

[0012] This has led to an increasing demand for a new battery management system that can detect a loose contact module without interrupting operation or disassembling the pack, and a battery pack including the same. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] Korean Patent Publication No. 10-2023-0116149 Summary of the Invention [Problem to be solved by the invention]

[0014] The present invention has been made in consideration of the above problems, and one object of the present invention is to provide a battery management system that can detect a poorly contacted module using a cell balancer.

[0015] Another object of the present invention is to provide a battery pack including the above-mentioned battery management system.

[0016] Another object of the present invention is to provide a method for detecting a loosely contacted module in a battery pack using the battery management system described above. [Means for solving the problem]

[0017] To achieve the above object, one embodiment of the present invention provides a battery management system that includes a plurality of slave management units that are arranged to correspond to a plurality of battery modules, respectively, and that perform a balancing operation to uniformly adjust the cell voltages of a plurality of battery cells that constitute the battery modules; a master management unit that detects a defective module, which is a battery module having poor internal contact, using a voltage deviation that is the difference between the maximum and minimum cell voltages; and a data transfer unit that electrically connects the master management unit and the slave management unit to each other and exchanges data.

[0018] To achieve the above object, a battery pack according to one embodiment of the present invention may include a lower case accommodating a plurality of battery modules aligned in a row; a plurality of slave management units individually disposed on top of the plurality of battery modules and performing a balancing operation to uniformly adjust the cell voltages of a plurality of battery cells constituting the battery module; a cover body covering the lower case and positioned on top of the slave management units and the battery modules; a master management unit disposed on the top surface of the cover body, connected to the plurality of slave management units, and detecting a defective module, which is a battery module having poor internal contact, using a voltage deviation that is the difference between the maximum and minimum cell voltages; and an upper case covering the master management unit and coupled to the lower case.

[0019] To achieve the above object, a method for detecting a poorly contacted module in a battery pack according to another embodiment of the present invention is disclosed. The method includes the steps of: first, generating a voltage deviation, which is a difference between a maximum value and a minimum value of cell voltages for a plurality of battery cells constituting a battery module, as a module deviation for the battery module; comparing the module deviation with a first reference value for performing a balancing operation on the battery module and a second reference value for checking for poor contact for the battery module; if the module deviation is a poor contact deviation that is smaller than the first reference value and larger than the second reference value, designating the battery module corresponding to the poor contact deviation as a fault-determined module; connecting a voltage regulator to all battery cells of the fault-determined module and performing an instantaneous discharge; generating a detection deviation for the voltage deviation of the fault-determined module subjected to the instantaneous discharge; and designating the fault-determined module having a detection deviation larger than a predetermined fault criterion as a faulty module. [Effects of the Invention]

[0020] According to the battery management system, the battery pack including the same, and the method for detecting a poorly contacted module using the same according to the present invention, a module to be suspected to be defective is selected based on a predetermined reference value, and the defective module can be detected by comparing the detected deviation, which is the voltage deviation after instantaneous discharge by a voltage regulator that performs cell balancing, with the module deviation.

[0021] This makes it possible to easily detect poor contact of the battery modules included in the battery pack without disassembling the battery pack. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a structural diagram showing a battery pack according to an embodiment of the present invention; [Figure 2] 2 is an exploded perspective view showing a battery module included in the battery pack shown in FIG. 1. [Figure 3] FIG. 2 is a diagram illustrating a battery management system for the battery pack shown in FIG. [Figure 4] 4 is a circuit diagram showing a cell balancer provided in the voltage regulator shown in FIG. 3. [Figure 5a] FIG. 10 is a diagram showing voltage deviation after applying instantaneous discharge to a normal battery module without poor contact. [Figure 5b] FIG. 10 is a diagram showing voltage deviation after applying instantaneous discharge to a normal battery module without poor contact. [Figure 5c] FIG. 10 is a diagram showing voltage deviation after applying instantaneous discharge to a normal battery module without poor contact. [Figure 6a] 10 is a diagram showing a voltage deviation after applying an instantaneous discharge to a battery module in which a contact failure has occurred. [Figure 6b] 10 is a diagram showing a voltage deviation after applying an instantaneous discharge to a battery module in which a contact failure has occurred. [Figure 6c]10 is a diagram showing a voltage deviation after applying an instantaneous discharge to a battery module in which a contact failure has occurred. [Figure 7] 4 is a flowchart illustrating a method for detecting a faulty module using the battery management system shown in FIG. 3. DETAILED DESCRIPTION OF THE INVENTION

[0023] <Summary of the Invention> To solve the above technical problems, a slave management unit according to one embodiment of the present invention may include a voltage detector that is individually connected to a plurality of battery cells and periodically detects cell voltages, a voltage regulator that is individually connected to the plurality of battery cells and has a plurality of cell balancers that perform balancing operations, and a module controller that obtains the cell voltages from the voltage detector, generates a voltage deviation for each battery module, and controls the operation of the battery module according to a control operation transferred from the master management unit.

[0024] A module controller according to one embodiment of the present invention for solving the above technical problems may include a module deviation generation unit that sets a voltage deviation periodically generated by a voltage detector as a module deviation for a corresponding battery module; a balance control unit that performs balancing operation by driving a voltage regulator for a balancing module, which is a corresponding battery module, for a first set time in response to a balancing signal transferred from a master management unit; and a detection deviation generation unit that drives a voltage regulator for a second set time shorter than the first set time in response to a fault detection signal transferred from the master management unit in response to a fault estimation module, which is a corresponding battery module, to generate a detection deviation, the voltage deviation for the fault estimation module.

[0025] To solve the above technical problems, a module controller according to one embodiment of the present invention includes an analog-to-digital signal converter, and module deviations, detection deviations, balancing signals, and fault detection signals can be transferred as digital data via a data transfer unit.

[0026] A data transfer unit according to an embodiment of the present invention for solving the above technical problems may include a wireless communication unit.

[0027] In one embodiment of the present invention to solve the above technical problem, the first set time may have a range of 1 hour or more, and the second set time may have a range of 20 seconds to 40 seconds.

[0028] To solve the above technical problems, a voltage regulator according to one embodiment of the present invention may be configured to separate even-numbered battery cell groups and odd-numbered battery cell groups of a fault estimation module, and apply half of the second set time to each battery cell group.

[0029] A voltage regulator according to one embodiment of the present invention for solving the above technical problem can be configured to simultaneously connect to all battery cells of a module that is estimated to be faulty and has a voltage distribution that does not require balancing because the module deviation is smaller than a first reference value set for balancing.

[0030] To solve the above technical problems, a cell balancer according to one embodiment of the present invention includes a passive balancer having a resistor and a discharge switch connected in parallel to the battery cells, and a voltage regulator may be configured to discharge all battery cells of a fault estimation module for a second set time.

[0031] A master management unit according to one embodiment of the present invention for solving the above technical problems may include: a control operation setter that stores module deviations transferred from the module controller, compares them with a predetermined reference value, and selects a control operation for a battery module corresponding to the module deviation; a balancing controller that, when the module deviation is a balance deviation greater than a first reference value that is a reference value set for a balancing operation, sets the battery module corresponding to the balance deviation as a balancing module and generates a balancing signal to control the balancing operation for the balancing module; and a fault detection controller that, when the module deviation is a poor contact deviation that is smaller than the first reference value and greater than a second reference value that is a reference value for poor contact detection, sets the battery module corresponding to the poor contact deviation as a fault estimation module and generates a fault detection signal to control the detection deviation generation operation for the fault estimation module.

[0032] A fault detection controller according to one embodiment of the present invention for solving the above technical problem may include a detection signal generation unit that generates and transmits a fault detection signal to a module controller through a control operation, a detection deviation storage unit that retrieves and stores a detection deviation for a fault estimation module from the detection deviation generation unit through the fault detection signal, and a fault judgment unit that judges the fault estimation module as a faulty module if the detection deviation is greater than a predetermined fault judgment criterion.

[0033] In one embodiment of the present invention to solve the above technical problem, the defect determination criteria are set to have a range of 40% to 60% of the module deviation for a defective module, and if the detected deviation is 0.4 to 0.6 times or more of the module deviation, the defective module can be determined to be a defective module.

[0034] According to an embodiment of the present invention for solving the above technical problem, the first reference value may have a range of 50 mV to 80 mV, and the second reference value may have a range of 30 mV to 40 mV.

[0035] To solve the above technical problems, a battery module according to one embodiment of the present invention includes a flat plate holder that fixes bus bars that sequentially connect a plurality of battery cells, and a signal transmission board that is fixed to the flat plate holder, and a slave management unit may be disposed on the signal transmission board.

[0036] To solve the above technical problems, a slave management unit according to one embodiment of the present invention may include a voltage detector that is individually connected to a plurality of battery cells and periodically detects cell voltages, a voltage regulator that is individually connected to the plurality of battery cells and has a plurality of cell balancers that perform balancing operations, and a module controller that obtains the cell voltages from the voltage detector, generates a voltage deviation for each battery module, and controls the operation of the battery module according to a control operation transferred from the master management unit.

[0037] A module controller according to one embodiment of the present invention for solving the above technical problems may include a module deviation generation unit that sets a voltage deviation periodically generated by a voltage detector as a module deviation for a corresponding battery module; a balance control unit that performs balancing operation by driving a voltage regulator for a balancing module, which is a corresponding battery module, for a first set time in response to a balancing signal transferred from a master management unit; and a detection deviation generation unit that drives a voltage regulator for a second set time shorter than the first set time in response to a fault detection signal transferred from the master management unit in response to a fault estimation module, which is a corresponding battery module, to generate a detection deviation, the voltage deviation for the fault estimation module.

[0038] A master management unit according to one embodiment of the present invention for solving the above technical problems may include: a control operation setter that stores module deviations transferred from the module controller, compares them with predetermined reference values, and selects a control operation for a battery module corresponding to the module deviation; a balancing controller that, when the module deviation is a balance deviation greater than a first reference value that is a reference value set for a balancing operation, sets the battery module corresponding to the balance deviation as a balancing module and generates a balancing signal to control the balancing operation for the balancing module; and a fault detection controller that, when the module deviation is a poor contact deviation that is smaller than the first reference value and greater than a second reference value that is a reference value set for poor contact detection, sets the battery module corresponding to the poor contact as a fault estimation module, generates a fault detection signal, and controls the detection deviation generation operation for the fault estimation module.

[0039] A fault detection controller according to one embodiment of the present invention for solving the above technical problem may include a detection signal generation unit that generates and transmits a fault detection signal to a module controller through a control operation, a detection deviation storage unit that retrieves and stores a detection deviation for a fault estimation module from the detection deviation generation unit through the fault detection signal, and a fault judgment unit that judges the fault estimation module as a faulty module if the detection deviation is greater than a predetermined fault judgment criterion.

[0040] <Detailed Description of the Invention> FIG. 1 is a structural view showing a battery pack according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view showing a battery module included in the battery pack shown in FIG.

[0041] Referring to FIGS. 1 and 2, a battery pack 1000 according to an embodiment of the present invention may include a plurality of battery modules 700 housed in a case 600, and a battery management system 500 including a slave manager 100 and a master manager 200.

[0042] For example, the case 600 includes a lower case 610 and an upper case 620, and a plurality of battery modules 700 and battery management systems 500 are disposed in an enclosed space formed by combining the lower case 610 and the upper case 620. Therefore, the case 600 may be made of various materials as long as it can accommodate the battery modules 700 and the battery management systems 500, stably protect them from external impact, and sufficiently dissipate the heat generated by the operation of the battery modules 700.

[0043] A large number of battery modules 700 can be arranged in a row inside the lower case 610 provided in the shape of a container.

[0044] The battery module 700 may include a battery frame 710 having a plurality of battery cells 711 and a flat plate holder 720 for fixing bus bars 721. A slave manager 100, which is a module battery management system (BMS) that controls the plurality of battery cells 711 individually, may be located on the flat plate holder 720.

[0045] FIG. 2 shows the configuration of an arbitrary battery module 700, and the plurality of battery modules 700 shown in FIG. 1 have substantially the same configuration.

[0046] As one example, the battery module 700 may include a hexahedral battery frame 710 and a plurality of battery cells 711 aligned in one direction and fixed within the battery frame 710. The plurality of battery cells 711 may be aligned in one direction on a bottom plate (not shown) and fixed by end plates 712 and side plates 713.

[0047] The battery cell 711 may include various unit cells capable of generating electrical energy. In the present invention, the battery cell 711 may be a secondary battery capable of reversibly charging and discharging. The plurality of battery cells 711 may be electrically connected to each other by a bus bar 721 that connects adjacent positive and negative terminals to each other.

[0048] The bus bar 721 may be made of a conductive member that electrically connects the positive or negative terminals of adjacent battery cells 711 by connecting them to each other. For example, the bus bar 721 may be made of a low-resistance metal plate and may be connected to the positive or negative terminals of adjacent battery cells 711. In this way, the plurality of battery cells 711 included in the battery frame 710 may be electrically connected to each other by the bus bar 721.

[0049] The flat plate holder 720 is provided as a flat plate that covers the top of the battery frame 710, fixes the bus bar 721, and can be fitted with a slave management unit 100 on top that can control the operation of the battery module 700, or a cooling means (not shown) that can absorb the heat generated by driving each battery cell 711.

[0050] The slave management unit 100 is individually disposed on top of the plurality of battery modules 700 and can perform a balancing operation to uniformly adjust the cell voltages of the plurality of battery cells 711 that constitute the battery module 700. The configuration and operation of the slave management unit 100 will be described in detail below.

[0051] A lid (C) is disposed to cover the top of the lower case, thereby sealing the slave management unit 100 from the outside. As a result, the battery module 700 and the slave management unit 100 are separated from the outside by the lid (C) while housed in the lower case 610. For example, the lid (C) is made of a resin composition having insulating properties and sufficient strength, and can electrically separate the slave management unit 100 located at the bottom from the master management unit 200 located at the top.

[0052] In this embodiment, the cover (C) is made of plastic and has a flat top surface to stably support the master manager 200. The master manager 200, which controls the multiple slave managers 100 and controls the multiple battery modules 700 to operate as a single energy source, is disposed on the top surface of the cover (C). As a result, the master manager 200, together with the slave managers 100, functions as a battery management system 500 for a battery pack that can manage the battery pack 1000. In particular, the master manager 200 is connected to the multiple slave managers 100 and can detect a defective module, which is a battery module with internal poor contact, using a voltage deviation, which is the difference between the maximum and minimum cell voltages. This allows for easy detection of a defective module, which is a battery module that is experiencing internal resistive discharge due to poor contact, without disassembling the battery modules 700 from the battery pack 1000.

[0053] FIG. 3 is a diagram illustrating a battery management system of the battery pack shown in FIG.

[0054] 3, one embodiment of the present invention discloses a battery management system 500 capable of adjusting the operation of a battery pack 1000 including a plurality of battery modules 700. For example, the battery management system 500 may include a slave manager 100 disposed on top of each battery module 700 and individually adjusting the operation of the corresponding battery module 700, and a master manager 200 connected to the slave manager 100 via a data transfer unit 300 and controlling the plurality of slave managers 100.

[0055] A plurality of slave management units 100 are provided according to the number of battery modules 700, whereas the master management unit 200 is provided as a single management unit for controlling the plurality of slave management units 100. However, it is clear that a plurality of master management units 200 can be arranged according to the characteristics of the battery pack 1000.

[0056] As an example, the slave management unit 100 is arranged to correspond to each of the plurality of battery modules 700, detects the operating characteristics of the battery modules 700, and can individually control the operation of the battery modules 700 based on the detected operating characteristics. For example, the slave management unit 100 can detect the cell voltage of each battery cell 711 using a voltage detector 110 (described later) and the cell temperature of each battery cell 711 using a temperature detector (not shown). The temperature and voltage of the battery cells 711 constituting each battery module 700 can be detected and processed to control the battery modules 700 so that they can be driven efficiently. Thus, the voltage and temperature act as operating characteristic factors that can control the operation of the battery modules 700.

[0057] In this embodiment, the use of cell voltage is disclosed to detect a defective module, which is a battery module 700 having poor contact inside, and operation control of the battery module 700 using cell temperature is not explicitly disclosed, but it is clear that each battery cell 711 or each battery module 700 can be appropriately cooled using cell temperature.

[0058] For example, the slave management unit 100 may include a voltage detector 110, a voltage regulator 120, and a module controller 130. The voltage detector 110 is individually connected to the positive and negative terminals of the battery cells 711 and can detect the cell voltage, which is the voltage across the battery cells 711. Therefore, the same number of voltage detectors 110 as the number of battery cells 711 can be provided. In particular, the voltage detectors 110 are configured to repeatedly detect the cell voltages of the battery cells 711 at predetermined intervals while the battery pack 1000 is operating. As the usage time of the battery pack 1000 increases, the degree of deterioration of each battery cell 711 varies depending on the individual manufacturing process characteristics and operating conditions. As a result, voltage deviations occur among the battery cells 711, and therefore voltage deviations also occur in the battery module 700 made up of the battery cells 711.

[0059] Thus, while the battery pack 1000 is operating, the voltage detector 110 periodically detects the cell voltages to observe the voltage distribution among the battery cells 711. In this embodiment, the cell voltage distribution of the battery module 700 is evaluated as a voltage deviation, which is the difference between the maximum voltage and the minimum voltage. However, this is merely an example, and the cell voltage distribution can be expressed as various physical quantities that can accurately describe the actual voltage distribution of the battery module 700.

[0060] The voltage detector 110 transfers the cell voltage of the corresponding battery module 700 to the module controller 130, and the voltage deviation is obtained through the module controller 130. For example, the voltage regulator 120 may be individually connected to a plurality of battery cells 711 and perform a balancing operation to uniformly distribute the cell voltages. Thus, if a specific battery module 700 exceeds an allowable voltage deviation, the balancing operation is performed by the voltage regulator 120. In this embodiment, the voltage regulator 120 may include a cell balancer (B) individually connected in parallel to each battery cell 711.

[0061] FIG. 4 is a circuit diagram showing a cell balancer provided in the voltage regulator shown in FIG.

[0062] 4, the voltage regulator 120 comprises a number of cell balancers (B) connected in parallel to each battery cell 711. As a result, similar to the voltage detector 110, the voltage regulators 120 can be arranged in the same number as the battery cells 711.

[0063] For example, the cell balancer (B) is provided as a passive balancer including a discharge resistor 121 and a discharge switch 122 and connected in parallel to the battery cells 711. When a balancing signal is applied to the battery module 700, the discharge switch 122 is connected and discharges from the battery cells 711 through the discharge resistor 121, thereby reducing the cell voltage of the battery cells 711. As a result, the battery cells 711 having a relatively high voltage are discharged, thereby reducing the voltage deviation between the battery cells 711 constituting the battery module 700.

[0064] For example, the module controller 130 obtains cell voltages from the voltage regulator 120, generates a voltage deviation for each battery module 700, and controls the operation of the battery module 700 according to a control operation signal transferred from the master manager 200. The module controller 130 controls the operation of the corresponding battery module 700 according to a control operation signal transferred from the master manager 200. For example, the module controller 130 can adjust the balancing operation or cooling operation for the battery module 700.

[0065] For example, the module controller 130 may include a module deviation generating unit 131, a balance control unit 132, and a detection deviation generating unit 133. The module deviation generating unit 131 can set the voltage deviation periodically generated by the voltage detector 110 as the module deviation for the corresponding battery module 700. The maximum cell voltage and the minimum cell voltage are detected by comparing the multiple cell voltages transferred from the voltage detector 110 with each other, and the voltage deviation is obtained from the difference between them. The voltage deviation is obtained for each battery module 700 and can be set as the module deviation for that battery module 700.

[0066] Therefore, the module deviation generating unit 131 can generate a module deviation, which is a voltage deviation divided for each battery module 700 .

[0067] The balance control unit 132 can drive the voltage regulator 120 for the balancing module, which is the corresponding battery module 700, for a first set time in response to the balancing signal transmitted from the master management unit 200, thereby performing a balancing operation on the balancing module.

[0068] As will be described later, a balancing signal is generated when a balance deviation, which is a module deviation greater than a predetermined comparison value, is detected, and a balancing operation can be performed on the balancing module, which is the battery module 700 corresponding to the balance deviation. Therefore, when the balancing signal is applied from the master manager 200 to the module controller 130, the balance control unit 132 can perform a balancing operation on the balancing module.

[0069] The detection deviation generating unit 133 can generate a voltage deviation for the fault estimation module as a detection deviation by driving the voltage regulator 120 for a second set time that is shorter than the first set time for the fault estimation module, which is the corresponding battery module 700, in response to the fault detection signal transferred from the master management unit 200. The detection deviation generating unit 133 performs instantaneous discharge using the voltage regulator 120 for the fault estimation module in response to the fault detection signal, and then detects the voltage deviation to obtain the detection deviation.

[0070] The signal converter 134 can convert the module deviation, the detection deviation, the balancing signal, and the fault detection signal into digital signals. This allows data transfer between the slave management unit 100 and the master management unit 200 to be performed as digital signals. For example, the signal converter 134 can be configured as an analog-to-digital converter. In particular, by transferring data between the slave management unit 100 and the master management unit 200 as digital signals, the data transfer unit 300 can also be configured as wireless communication means.

[0071] The balancing operation for the battery modules 700 is performed over a relatively long period of time, but the discharging operation for detecting a defective module is performed instantaneously.

[0072] As will be described later, the discharge operation for detecting a faulty module is performed on battery modules 700 that do not have a voltage deviation large enough to require a balancing operation. Therefore, if a module deviation is large enough to require a balancing operation, the voltage deviation is first reduced by a balancing operation before the contact failure detection operation is performed. Therefore, for battery modules 700 that do not require a balancing operation, discharge is performed for a short period of time that does not impair the stabilized voltage deviation.

[0073] For example, the first set time is set to be one hour or more, or in the range of several hours to several tens of hours, and the second set time is set to be in the range of about 20 seconds to about 40 seconds. In particular, when the voltage regulator 120 performs an instantaneous discharge on the fault estimation module, it is preferable to group the battery cells 711 and perform the instantaneous discharge sequentially on each group, rather than simultaneously on all the battery cells 711, in order to improve the uniformity of the instantaneous discharge. For example, the battery cells 711 of the fault estimation module may be divided into even-numbered battery cell groups and odd-numbered battery cell groups, and an instantaneous discharge may be applied to each battery cell group sequentially for half the second set time.

[0074] 5a to 5c and 6a to 6c are diagrams illustrating a process of checking whether or not there is a contact failure in the failure estimation module using a momentary discharge by a voltage regulator.

[0075] 5a to 5c are diagrams showing voltage deviations after applying an instantaneous discharge to a normal battery module without poor contact.

[0076] Fig. 5a is a diagram showing the voltages in each battery cell 711 of a normal module, Fig. 5b is a diagram showing the voltages in each battery cell 711 due to instantaneous discharge applied to the normal module, and Fig. 5c is a diagram in which Fig. 5a and Fig. 5b are superimposed.

[0077] The battery module in Figure 5a is a normal module (NM) with no poor contact, and there is some deviation in the cell voltage of each battery cell 711. In Figure 5a, the size of the hatching filling each battery cell 711 indicates the cell voltage. Therefore, the voltage deviation of a normal module (NM) can be determined by the difference between the maximum cell voltage (Vmax) and the minimum cell voltage (Vmin).

[0078] 5b, the voltage regulator 120 is momentarily connected to all battery cells 711 of the normal module (NM) to perform an instantaneous discharge. When the discharge switch is connected for a short time, such as the second set time, the same amount of electrical energy is discharged from all battery cells 711. In particular, the instantaneous discharge allows the potential deviation of the normal module (NM) to remain stable.

[0079] FIG. 5c is a superposition of FIG. 5a and FIG. 5b, showing a state in which the discharge voltage of FIG. 5b is removed from the cell voltage of FIG. 5a and a residual voltage (RV) is applied to each battery cell 711.

[0080] Because the uniform discharge voltage (DV) is removed from the cell voltage (CV) in Figure 5a, the voltage distribution of the cell voltage (CV) becomes the same as the voltage distribution of the residual voltage (RV). As a result, even if an instantaneous discharge is applied to a normal module (NM), the voltage deviation remains the same. However, as shown in Figures 6a to 6c, if a contact failure occurs within the battery module, the current deviation changes due to resistive discharge from the fault point.

[0081] 6a to 6c are diagrams showing voltage deviations after applying an instantaneous discharge to a battery module in which a contact failure has occurred.

[0082] The battery module in Figure 6a is a defective module (AM) where poor contact has occurred, and there is some deviation in the cell voltage (CV) of each battery cell 711. In Figure 6a, the size of the hatching filling each battery cell 711 indicates the cell voltage. Therefore, the voltage deviation of the defective module (AM) can be determined by the difference between the maximum cell voltage (Vmax) and the minimum cell voltage (Vmin).

[0083] Referring to Figure 6b, the voltage regulator 120 is momentarily brought into contact with all battery cells 711 of the defective module (AM) to perform an instantaneous discharge. When the discharge switch is connected for a short time, such as the second set time, the same amount of electrical energy is discharged from all battery cells 711. In particular, as in Figure 5b, the instantaneous discharge allows the potential deviation of the defective module (AM) to remain stable.

[0084] FIG. 6c is a superposition of FIG. 6a and FIG. 6b, showing a state in which the discharge voltage of FIG. 6b is removed from the cell voltage of FIG. 6a and a residual voltage (RV) is applied to each battery cell 711.

[0085] Although a uniform discharge voltage (DV) should be removed from the cell voltage (CV) in FIG. 6a, the defective cell (DC) with poor contact discharges more than the battery cell 711 without poor contact due to excessive resistive discharge. As a result, the defective module (AM) has the same maximum cell voltage (Vmax), but the residual voltage (RV) of the defective cell (DC) becomes the new minimum cell voltage (Vmin), resulting in a greater voltage deviation in FIG. 6c than that in FIG. 6a. When voltage regulator 120 performs an instantaneous discharge on a module with a stable voltage deviation, normal cells exhibit a residual voltage reduced by the discharge voltage, whereas a defective cell with poor contact experiences a further reduction in residual voltage (RV) due to resistive discharge caused by the poor contact, increasing the current deviation. Therefore, if the voltage deviation before and after instantaneous discharge by voltage regulator 120 exceeds the reference value, it can be determined that there is a defective cell causing poor contact.

[0086] Since it is necessary to determine whether there is a contact failure based on the degree of discharge of the battery cell 711, the voltage regulator 120 is configured as a passive balancer.

[0087] In one embodiment, the master manager 200 may include a control operation setter 210 , a balancing controller 220 , and a fault detection controller 230 .

[0088] The control action setter 210 stores the module deviations transferred from the module controller 130, compares them with predetermined reference values, and selects a control action for the battery module corresponding to the module deviation. Due to the periodic operation of the voltage detector 110, the module deviations of each battery module 700 are periodically transferred to the control action setter 210. The control action setter 210 compares the module deviations with the stored reference values, detects battery modules that require operational control, and performs the required control action.

[0089] In this embodiment, the control operations of the master manager 200 for the battery modules 700 may include a balancing operation and a contact failure detection operation. The reference values ​​may include a first reference value for performing the balancing operation and a second reference value for performing the contact failure detection operation. In this embodiment, the first reference value may range from 50 mV to 80 mV, and the second reference value may range from 30 mV to 40 mV. For example, if the first reference value is 80 mV and the second reference value is 40 mV, the balancing operation is performed for battery modules 700 whose transferred module deviation is 80 mV or more, and the contact failure detection operation is performed for battery modules 700 whose transferred module deviation is 50 mV.

[0090] Therefore, when the module deviation is a balance deviation greater than the first reference value, which is a reference value set for the balancing operation, the balancing controller 220 sets the battery module 700 corresponding to the balance deviation as a balancing module, generates a balancing signal, and controls the balancing operation for the balancing module.

[0091] Furthermore, when the module deviation is a poor contact deviation that is smaller than a first reference value and larger than a second reference value that is a reference value for detecting poor contact, the fault detection controller 230 may set the battery module 700 corresponding to the poor contact deviation as a fault estimation module, generate a fault detection signal, and control a detection deviation generation operation for the fault estimation module. For example, the fault detection controller 230 may include a detection signal generation unit 231 that generates and transmits a fault detection signal to the module controller 130 through a control operation, a detection deviation storage unit 232 that retrieves and stores the detection deviation for the fault estimation module from the detection deviation generation unit in accordance with the fault detection signal, and a fault determination unit 233 that determines the fault estimation module as a faulty module when the detection deviation is larger than a predetermined fault determination criterion.

[0092] If a module deviation between the first reference value and the second reference value is detected, it is set as a contact failure deviation, and the battery module 700 corresponding to the contact failure deviation is set as a fault estimation module. At the same time, a fault detection signal is generated and transmitted to the module controller 130. The module controller 130 drives the detection deviation generating unit 133 by the fault detection signal to obtain the detection deviation for the fault estimation module.

[0093] As described above, the voltage regulator 120 is applied simultaneously to all battery cells 711 of the fault estimation module, and an instantaneous discharge is performed for the second set time. After the instantaneous discharge, the voltage detector 110 detects the cell voltage of each battery cell 711 of the fault estimation module, and the difference between the maximum cell voltage and the minimum cell voltage is obtained as the detection deviation. The detection deviation is stored in the detection deviation storage unit 232.

[0094] The fault determination unit 233 compares the transferred module deviation with a predetermined fault determination criterion to determine whether the module is faulty. If the module deviation of the fault-presumed module satisfies the fault determination criterion, the module is determined to be faulty; if it does not, the module is determined to be normal. For example, the fault determination criterion can be set to fall within the range of 40% to 60% of the module deviation for the fault-presumed module. In this case, if the detected deviation is 0.4 to 0.6 times or more the module deviation, the fault-presumed module is determined to be faulty.

[0095] If a defective module is detected, the battery pack 1000 is disassembled into battery modules, and the defective module is replaced with a new module.

[0096] A battery pack having the above-described battery management system can select a module to be suspected of being defective based on a predetermined reference value, and detect the defective module by comparing the module deviation with a detected deviation, which is a voltage deviation after instantaneous discharge by the voltage regulator 120 that performs cell balancing. This makes it possible to easily detect poor contact of a battery module included in a battery pack without disassembling the battery pack.

[0097] FIG. 7 is a flowchart illustrating a method for detecting a faulty module using the battery management system shown in FIG.

[0098] Referring to FIG. 7, first, a voltage deviation, which is the difference between the maximum and minimum values ​​of cell voltages for a plurality of battery cells 711 constituting a battery module 700, is generated as a module deviation for the battery module 700 (step S100).

[0099] The battery pack 1000 is made up of a plurality of battery modules 700. While the battery pack 1000 is operating, the voltage detector 110 periodically detects the cell voltage of each battery module 700, and the module controller 130 obtains the voltage deviation for each battery module 700 and sets it as the module deviation. The module deviation is transferred to the master manager 200 and compared with a reference value.

[0100] Next, the master manager 200 compares the module deviation with a first reference value for performing a balancing operation on the battery module 700 and a second reference value for checking for poor contact on the battery module 700 (step S200), and determines a control operation for the battery module. At this time, the first reference value and the second reference value may be input via an interface 400 connected to the master manager 200.

[0101] If the module deviation is a contact failure deviation between the first reference value and the second reference value, the battery module corresponding to the contact failure deviation is set as a fault estimation module (step S300), and a voltage regulator is connected to all battery cells of the fault estimation module to perform instantaneous discharge (step S400).

[0102] Since the voltage deviation of the fault estimation module is lower than the first reference value, each battery cell 711 maintains a stable state, so when an instantaneous discharge is applied to the fault estimation module, each battery cell 711 discharges at the same rate.

[0103] After generating the voltage deviation of the defective estimated module that has undergone instantaneous discharge as a detected deviation (step S500), the defective estimated module having a detected deviation greater than a predetermined defect determination criterion is set as a defective module (step S600).

[0104] If there is no poor contact, all battery cells 711 discharge evenly, so there is no difference in voltage deviation before and after the instantaneous discharge. However, if there is poor contact, a resistive discharge occurs from the defective cell with the poor contact, resulting in a higher discharge voltage.

[0105] As a result, if the increase in the detected deviation exceeds 40% to 60% of the module deviation, the module is detected as a defective module.

[0106] According to the above-described battery management system, the battery pack including the same, and the method for detecting a poorly contacted module using the same, a module to be suspected to be defective is selected based on a predetermined reference value, and the defective module can be detected by comparing the detected deviation, which is the voltage deviation after instantaneous discharge by a voltage regulator that performs cell balancing, with the module deviation.

[0107] This makes it possible to easily detect poor contact of the battery modules included in the battery pack without disassembling the battery pack. [Explanation of symbols]

[0108] 100 Slave Management Department 200 Master Management Department 300 Data Transfer Unit 400 Interface 500 Battery Management System 600 cases 700 Battery Module 1000 battery pack

Claims

1. a plurality of slave management units arranged to correspond to the plurality of battery modules, respectively, and performing a balancing operation to uniformly adjust the cell voltages of the plurality of battery cells constituting the battery modules; a master management unit that detects a defective module, which is the battery module having a poor internal contact, using a voltage deviation that is a difference between the maximum and minimum values ​​of the cell voltage; a data transfer unit electrically connecting the master management unit and the slave management unit to each other and exchanging data.

2. The slave management unit a voltage detector connected to each of the plurality of battery cells and configured to periodically detect the cell voltage; a voltage regulator including a plurality of cell balancers individually connected to the plurality of battery cells and performing the balancing operation; a module controller that obtains the cell voltages from the voltage detectors, generates the voltage deviation for each battery module, and controls an operation of the battery module according to a control operation transferred from the master manager.

3. The module controller a module deviation generating unit that sets the voltage deviation periodically generated by the voltage detector as a module deviation for the corresponding battery module; a balance control unit that drives the voltage regulator for a first set time to perform the balancing operation for the balancing module, which is the corresponding battery module, in response to the balancing signal transferred from the master management unit; and a detection deviation generating unit configured to drive the voltage regulator for a second set time period shorter than the first set time period for a failure estimation module that is the corresponding battery module in response to the failure detection signal transferred from the master management unit, and generate the voltage deviation for the failure estimation module as a detection deviation.

4. 4. The battery management system according to claim 3, wherein the module controller includes an analog-to-digital converter, and the module deviation, the detection deviation, the balancing signal, and the fault detection signal are transferred as digital data via the data transfer unit.

5. The battery management system according to claim 4 , wherein the data transfer unit includes a wireless communication unit.

6. The battery management system of claim 3 , wherein the first set time period has a range of one hour or more, and the second set time period has a range of 20 seconds to 40 seconds.

7. 7. The battery management system according to claim 6, wherein the voltage regulator is configured to divide the even-numbered battery cell group and the odd-numbered battery cell group of the fault estimation module into groups and apply half of the second set time to each of the groups.

8. 4. The battery management system of claim 3, wherein the voltage regulator is configured to simultaneously connect to all battery cells of the fault estimation module having a voltage distribution for which the balancing operation is unnecessary because the voltage deviation is smaller than a first reference value set for the balancing operation.

9. 9. The battery management system of claim 8, wherein the cell balancer includes a passive balancer including a resistor and a discharge switch connected in parallel to the battery cells, and the voltage regulator is configured to discharge all of the battery cells of the fault estimation module for the second set time.

10. The master management unit a control action setter that stores the module deviation transferred from the module controller, compares it with a predetermined reference value, and selects a control action for the battery module corresponding to the module deviation; a balancing controller that, when the module deviation is a balance deviation greater than a first reference value that is a reference value set for the balancing operation, sets the battery module corresponding to the balance deviation as the balancing module, generates the balancing signal, and controls the balancing operation for the balancing module; and a fault detection controller that, when the module deviation is a poor contact deviation that is smaller than the first reference value and larger than a second reference value that is a reference value for poor contact detection, sets the battery module corresponding to the poor contact deviation as the fault estimation module, generates the fault detection signal, and controls a detection deviation generation operation for the fault estimation module.

11. The fault detection controller a detection signal generating unit that generates and transmits the fault detection signal to the module controller according to the control operation; a detection deviation storage unit that retrieves the detection deviation for the fault estimation module from the detection deviation generation unit and stores it in response to the fault detection signal; The battery management system according to claim 10 , further comprising: a fault determination unit that determines the fault estimation module as a faulty module when the detected deviation is greater than a predetermined fault determination criterion.

12. 12. The battery management system of claim 11, wherein the fault determination criterion is set to have a range of 40% to 60% of the module deviation for the fault estimation module, and when the detected deviation is 0.4 to 0.6 times or more of the module deviation, the fault estimation module is determined to be the faulty module.

13. The battery management system of claim 10 , wherein the first reference value has a range of 50 mV to 80 mV, and the second reference value has a range of 30 mV to 40 mV.

14. a lower case that accommodates a plurality of battery modules aligned in a row; a plurality of slave management units disposed individually on top of the plurality of battery modules and performing a balancing operation to uniformly adjust cell voltages of a plurality of battery cells constituting the battery modules; a cover that covers the lower case and is positioned on the slave management unit and the battery module; a master management unit disposed on an upper surface of the cover, connected to the plurality of slave management units, and configured to detect a defective module, which is a battery module having a poor internal contact, using a voltage deviation that is a difference between a maximum value and a minimum value of the cell voltages; an upper case covering the master management unit and coupled to the lower case.

15. the battery module includes a flat plate holder that fixes bus bars that sequentially connect the plurality of battery cells, and a signal transmission board that is fixed to the flat plate holder, The battery pack according to claim 14 , wherein the slave management unit is disposed on the signal transfer board.

16. The slave management unit a voltage detector connected to each of the plurality of battery cells and configured to periodically detect the cell voltage; a voltage regulator including a plurality of cell balancers individually connected to the plurality of battery cells and performing the balancing operation; a module controller that obtains the cell voltages from the voltage detectors, generates the voltage deviation for each battery module, and controls an operation of the battery module according to a control operation transferred from the master management unit.

17. The module controller a module deviation generating unit that sets the voltage deviation periodically generated by the voltage detector as a module deviation for the corresponding battery module; a balance control unit that drives the voltage regulator for a first set time to perform the balancing operation for the balancing module, which is the corresponding battery module, in response to the balancing signal transferred from the master management unit; and a detection deviation generating unit configured to drive the voltage regulator for a second set time shorter than the first set time for a fault estimation module that is the corresponding battery module in response to the fault detection signal transferred from the master management unit, and generate the voltage deviation for the fault estimation module as a detection deviation.

18. The master management unit a control action setter that stores the module deviation transferred from the module controller, compares it with a predetermined reference value, and selects a control action for the battery module corresponding to the module deviation; a balancing controller that, when the module deviation is a balance deviation greater than a first reference value that is the reference value set for the balancing operation, sets the battery module corresponding to the balance deviation as a balancing module, generates the balancing signal, and controls the balancing operation for the balancing module; a fault detection controller that, when the module deviation is a poor contact deviation that is smaller than the first reference value and larger than a second reference value that is the reference value set for poor contact detection, sets the battery module corresponding to the poor contact as the fault estimation module, generates a fault detection signal, and controls a detection deviation generation operation for the fault estimation module.

19. The fault detection controller a detection signal generating unit that generates and transmits the fault detection signal to the module controller according to the control operation; a detection deviation storage unit that retrieves the detection deviation for the fault estimation module from the detection deviation generation unit and stores it in response to the fault detection signal; 19. The battery pack according to claim 18, further comprising: a fault determination unit that determines the fault estimation module as a faulty module when the detected deviation is greater than a predetermined fault determination criterion.

20. generating a voltage deviation, which is a difference between a maximum value and a minimum value of cell voltages for a plurality of battery cells constituting a battery module, as a module deviation for the battery module; comparing the module deviation with a first reference value for performing a balancing operation on the battery module and a second reference value for checking for poor contact on the battery module; If the module deviation is a contact failure deviation that is smaller than the first reference value and larger than the second reference value, setting the battery module corresponding to the contact failure deviation as a failure estimation module; connecting a voltage regulator to all the battery cells of the fault estimation module and performing instantaneous discharge; generating the voltage deviation of the fault estimation module in which instantaneous discharge has occurred as a detection deviation; and setting the defective estimation module having the detection deviation greater than a predetermined defective criterion as a defective module.

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