Battery management system, battery device, and balancing method

Abstract

A battery management system connected to a battery module including a plurality of battery cells includes a plurality of cell balancing circuits and a control circuit to control the plurality of cell balancing circuits. Each cell balancing circuit includes: a DC / DC converter shared by a corresponding odd-numbered battery cell and a corresponding even-numbered battery cell among the plurality of battery cells and having an output terminal connected to a positive terminal of the battery module; a first switch connected between the corresponding odd-numbered battery cell and an input terminal of the DC / DC converter; and a second switch connected between the corresponding even-numbered battery cell and the input terminal.

Description

Battery management system, battery device, and balancing method

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2025-0015594 filed on February 7, 2025, and all contents disclosed in the document of said Korean patent application are incorporated herein as part of this specification.

[0003] The disclosure relates to a battery management system, a battery device, and a balancing method.

[0004] Electric or hybrid vehicles are vehicles that generate power by driving a motor primarily using a battery as a power source, and active research is being conducted on them as an alternative capable of solving the pollution and energy problems associated with internal combustion engine vehicles. In addition, batteries are used in various external devices other than vehicles.

[0005] Multiple battery cells are connected in series inside the battery, and voltage deviations between battery cells can cause over-discharge or over-charge of the battery cells and reduce the lifespan of the battery cells. To improve these voltage deviations, a cell balancing circuit is designed inside the battery management system.

[0006] Cell balancing circuits can be classified into active balancing circuits and passive balancing circuits. Conventional active balancing circuits have one DC (direct current) / DC converter connected to each battery cell, so the size and unit cost of the battery management system increase due to the many DC / DC converters. In addition, conventional active balancing circuits only balance even-numbered battery cells or only odd-numbered battery cells, so when balancing even-numbered battery cells, components for balancing odd-numbered battery cells are wasted, and when balancing odd-numbered battery cells, components for balancing even-numbered battery cells may be wasted.

[0007] Some embodiments may provide a battery management system, a battery device, and a balancing method capable of efficiently performing active balancing.

[0008] According to some embodiments, a battery management system connected to a battery module comprising a plurality of battery cells may include a plurality of cell balancing circuits and a control circuit for controlling the plurality of cell balancing circuits. Each cell balancing circuit may include a DC / DC converter, which is shared by a corresponding odd-numbered battery cell and a corresponding even-numbered battery cell among the plurality of battery cells and whose output terminal is connected to the positive terminal of the battery module, a first switch connected between the odd-numbered battery cell and the input terminal of the DC / DC converter, and a second switch connected between the even-numbered battery cell and the input terminal.

[0009] According to some embodiments, a battery device may include a battery module comprising a plurality of battery cells, a plurality of cell balancing circuits, and a control circuit for controlling the plurality of cell balancing circuits. Each cell balancing circuit includes a DC / DC converter that is shared by a corresponding odd-numbered battery cell and a corresponding even-numbered battery cell among the plurality of battery cells, and whose output terminal is connected to the positive terminal of the battery module, and may balance one of the odd-numbered battery cell and the even-numbered battery cell through the DC / DC converter in response to the control of the control circuit, and then balance the other battery cell.

[0010] According to some embodiments, a balancing method for a battery module including a plurality of battery cells may include the steps of: discharging an odd-numbered group of battery cells among the plurality of battery cells to charge the battery module; after discharging the odd-numbered group of battery cells, discharging the battery module to charge the odd-numbered group of battery cells; discharging an even-numbered group of battery cells among the plurality of battery cells to charge the battery module; and after discharging the even-numbered battery cells, discharging the battery module to charge the even-numbered group of battery cells.

[0011] FIG. 1 is a block diagram showing a battery device according to some embodiment.

[0012] FIG. 2 is a drawing showing a battery device according to a certain embodiment.

[0013] FIGS. 3, FIGS. 4, FIGS. 5 and FIGS. 6 are drawings illustrating the balancing operation of a battery device according to some embodiment.

[0014] FIG. 7 is a diagram showing a cell balancing circuit according to a certain embodiment.

[0015] FIG. 8 is a diagram showing a cell balancing circuit according to a certain embodiment.

[0016] FIG. 9 is a flowchart illustrating a balancing method according to a certain embodiment.

[0017] Embodiments of the present invention are described below with reference to the attached drawings so that those skilled in the art can easily implement them. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. Furthermore, in order to clearly explain the present invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification are denoted by similar reference numerals.

[0018] When it is stated that a component is "connected" to another component, it should be understood that it may be directly connected to that other component, or that there may be other components in between. On the other hand, when it is stated that a component is "directly connected" to another component, it should be understood that there are no other components in between.

[0019] Expressions written in the singular in the description below may be interpreted as singular or plural unless explicit expressions such as "one" or "singular" are used.

[0020] In the flowchart described with reference to the drawings, the order of operations may be changed, multiple operations may be merged or some operations may be divided, and specific operations may not be performed.

[0021] FIG. 1 is a block diagram showing a battery device according to some embodiment.

[0022] Referring to FIG. 1, the battery device (100) may include a battery module (110), a battery management system (BMS) (120), and switches (131, 132). The battery device (100) may be electrically connected to an external device through a positive link terminal (P+) and a negative link terminal (P-). In some embodiments, if the external device is a load, the battery device (100) may be discharged by operating as a power source that supplies power to the load. If the external device is a charger, the battery device (100) may be charged by receiving external power through the charger. In some embodiments, the external device operating as a load may be, for example, an electronic device, a means of transportation, or an energy storage system (ESS), and the means of transportation may be, for example, a vehicle such as an electric vehicle, a hybrid vehicle, or smart mobility. The battery device (100) may be a battery pack.

[0023] A battery module (110) may include a plurality of battery cells (not shown). In some embodiments, the plurality of battery cells may be connected in series. In some embodiments, a battery device (100) may include a plurality of battery modules (110). Each of the plurality of battery cells of the battery module (110) may be connected to a battery management system (120) via wiring.

[0024] Switch (131) may be connected between the positive terminal (B+) and the positive link terminal (P+) of the battery module (110), and switch (132) may be connected between the negative terminal (B-) and the negative link terminal (P-) of the battery module (110). Switches (131, 132) may be controlled by a battery management system (120) to control the connection between the battery device (100) and an external device. In some embodiments, switches (131, 132) may each include a contactor including a relay. In some embodiments, switches (131, 132) may each include an electrical switch such as a transistor. In some embodiments, the battery device (100) may further include a driving circuit (not shown) that drives switches (131, 132) in response to a control signal from the battery management system (120).

[0025] The battery management system (120) can collect and analyze information about the battery cells to control the charging and discharging of the battery cells, cell balancing, protection operations, etc. The battery management system (120) may include a balancing circuit (121), a battery monitoring circuit (122), and a processor (123).

[0026] A battery monitoring circuit (122) can be connected to a plurality of battery cells included in a battery module (110) via wiring to monitor the state of the battery cells (e.g., cell voltage). In some embodiments, the battery monitoring circuit (122) may include a plurality of battery monitoring circuits (122) corresponding to each of the plurality of battery modules (110). In some embodiments, one battery monitoring circuit (122) may correspond to two or more battery modules (110), or two or more battery monitoring circuits (122) may correspond to one battery module (110). In some embodiments, the battery monitoring circuit (122) may be provided as an integrated circuit (IC), and the battery monitoring circuit (122) provided as an integrated circuit is referred to as a battery monitoring IC (BMIC).

[0027] The balancing circuit (121) can balance multiple battery cells based on the voltage of the battery cells measured by the battery monitoring circuit (122). The balancing circuit (121) may include multiple cell balancing circuits (not shown), and each cell balancing circuit may be connected to two corresponding battery cells among the multiple battery cells to perform balancing of the two corresponding battery cells. Thus, two battery cells may share one cell balancing circuit. In some embodiments, each cell balancing circuit is shared by adjacent odd-numbered battery cells and even-numbered battery cells, and after balancing one of the odd-numbered battery cells and the even-numbered battery cells, balancing of the other battery cell may be performed. While balancing odd-numbered battery cells in each cell balancing circuit, balancing of corresponding odd-numbered battery cells in other cell balancing circuits can be performed, and while balancing even-numbered battery cells in each cell balancing circuit, balancing of corresponding even-numbered battery cells in other cell balancing circuits can be performed.

[0028] The processor (123) receives monitoring information from the battery monitoring circuit (122) and can control the operation of the battery monitoring circuit (122). The processor (123) can control the operation of the switches (131, 132). The processor (123) is a processing circuitry, and may be, for example, a microcontroller unit (MCU).

[0029] In some embodiments, the battery monitoring circuit (122) and / or processor (123) may operate as a control circuit that controls the operation of the balancing circuit (121).

[0030] FIG. 2 is a drawing showing a battery device according to some embodiment, and FIG. 3, FIG. 4, FIG. 5 and FIG. 6 are drawings explaining the balancing operation of a battery device according to some embodiment.

[0031] Referring to FIG. 2, the battery device (200) comprises a battery module (210), a battery monitoring circuit (220), and a plurality of cell balancing circuits (2301, 2302, ..., 230 N / 2 It may include a control circuit (240).

[0032] The battery module (210) consists of a plurality of battery cells (C1, C2, ..., C) connected in series. N It may include a plurality of battery cells (C1-C N The last battery cell among ) (e.g., the top battery cell) (C N The positive terminal of ) is connected to the positive terminal (B+) of the battery module (210), and a plurality of battery cells (C1-C N The negative terminal of the first battery cell (e.g., the lowest battery cell) (C1) among the batteries can be connected to the negative terminal (B-) of the battery module (210).

[0033] The battery monitoring circuit (220) comprises a plurality of battery cells (C1-C N Connected to the positive and negative electrodes of the battery cell (C1-C) through wiring N The voltage of ) can be monitored. In some embodiments, the battery monitoring circuit (220) may be provided as a BMIC (220).

[0034] Each cell balancing circuit (230 i ) is a plurality of battery cells (C1-C N The two corresponding battery cells among ), that is, the corresponding odd-numbered battery cell (C 2i-1 ) and the even-numbered battery cell (C) corresponding to it 2i Connected to ), two battery cells (C 2i-1 , C 2i ) can be balanced. Here, i is an integer between 1 and N / 2.

[0035] Each cell balancing circuit (230 i ) is a DC / DC converter (231 i It may include a DC / DC converter (231 i ) may be a dual-input single-output DC / DC converter. In some embodiments, the DC / DC converter (231 i ) can be an inductor-based DC / DC converter. DC / DC converter (231 i One of the dual inputs (the first input) of ) is the corresponding odd-numbered battery cell (C 2i-1 Connected to the odd-numbered battery cell (C 2i-1 The voltage of ) is received as input, and the other input (second input) is the corresponding even-numbered battery cell (C 2i Connected to ) even-numbered battery cells (C 2i It can receive the voltage of ). DC / DC converter (231 i The output of ) is the positive terminal (B+) of the battery module (210), that is, the last battery cell (C N It can be connected to the positive (B+) of ).

[0036] In some embodiments, each cell balancing circuit (230 i ) is a DC / DC converter (231 i The odd-numbered battery cell (C) corresponding to the negative input of the first input among the dual inputs of ) 2i-1 A switch (232) connected between the negative electrodes of ) i ) and the odd-numbered battery cell (C) corresponding to the positive input of the first input among the dual inputs. 2i-1 A switch (233) connected between the positive and negative poles of ) i It may further include ). Each cell balancing circuit (230 i ) is a DC / DC converter (231 i The even-numbered battery cell (C) corresponding to the negative input of the second input among the dual inputs of ) 2i A switch (234) connected between the negative electrodes of ) i) and the even-numbered battery cell (C) corresponding to the positive input of the second input among the dual inputs. 2i A switch (235) connected between the positive and negative poles of ) i It may include additional switches (232 i , 233 i When the DC / DC converter (231) is turned on, i ) is the odd-numbered battery cell (C 2i-1 After operating with the voltage of ) as input, it can operate with the voltage of the battery module (210) as input. Switch (234 i , 235 i When the DC / DC converter (231) is turned on, i ) is the even-numbered battery cell (C 2i After operating with the voltage of ) as input, it can operate with the voltage of the battery module (210) as input. In some embodiments, the switch (232 i , 233 i , 234 i , 235 i ) is a DC / DC converter (231 i It can be provided in the composition of ).

[0037] The control circuit (240) monitors the battery cells (C1-C) monitored by the battery monitoring circuit (220). N Cell balancing circuit based on the voltage of ) (2301-230 N / 2 ) can be controlled. In some embodiments, the control circuit (240) can control the battery cells (C1-C N The lowest voltage among the voltages of the battery cells (C1-C) up to the battery cell voltage N Cell balancing circuit (2301-230) so that ) discharges N / 2 Can control ).

[0038] The control circuit (240) is an odd-numbered battery cell (C1, C3, ..., C N-1 ) group and even-numbered battery cells(C2, C4, ..., C NA cell balancing circuit (2301-230) to balance one group first and then balance the other group. N / 2 ) can be controlled. For example, the control circuit (240) can control odd-numbered battery cells (C1, C3, C N-1 After balancing only ), the even-numbered battery cells (C2, C4, C N Cell balancing circuit (2301-230) to balance only ) N / 2 ) can be controlled. As another example, the control circuit (240) can control the even-numbered battery cells (C2, C4, C N After balancing only ), the odd-numbered battery cells (C1, C3, C N-1 Cell balancing circuit (2301-230) to balance only ) N / 2 Can control ).

[0039] Odd-numbered battery cells (C1, C3, C N-1 When balancing ), as shown in FIG. 3, the control circuit (240) is an odd-numbered battery cell (C 2i-1 A cell balancing circuit (230) to discharge ) i ) DC / DC converter (231 i ) can be controlled (S310). Discharged battery cell (C 2i-1 The energy of ) is the positive terminal (B+) of the battery module (210), that is, the uppermost battery cell (C N The energy can be transferred to the positive electrode of the battery module (210) and charged (S320). For example, the energy of the discharged odd-numbered battery cells can be transferred to a plurality of battery cells (C1-C) included in the battery module (210). N It can be charged in ). Next, as shown in FIG. 4, the control circuit (240) discharges the battery module (210) by using a DC / DC converter (231 i ) can be controlled (S410). The energy of the discharged battery module (210) is used to control the corresponding odd-numbered battery cell (C 2i-1 As it is transferred to the battery cell (C1-C NTo make the voltage of the battery cells (C1-C) uniform, N ) can be charged (S420). In this case, the odd-numbered battery cell (C 2i-1 Switch (232) connected to ) i , 233 i ) is turned on, and the even-numbered battery cell (C 2i The switch (234) connected to ) i , 235 i ) can be turned off. In some embodiments, the battery cell (C 2i-1 When ) is discharged, the cell balancing circuit (230 i ) DC / DC converter (231 i ) operates in dual-input single-output boost mode, and the battery cell (C 2i-1 When ) is charged, the DC / DC converter (231 i ) can operate in single-input dual-output buck mode.

[0040] Likewise, the even-numbered battery cells (C2, C4, C N When balancing ), as shown in FIG. 5, the control circuit (240) is an even-numbered battery cell (C 2i A cell balancing circuit (230) to discharge ) i ) DC / DC converter (231 i ) can be controlled (S510). Discharged battery cell (C 2i The energy of ) is the positive terminal (B+) of the battery module (210), that is, the uppermost battery cell (C N The energy can be transferred to the positive electrode of the battery module (210) and charged (S520). For example, the energy of the discharged even-numbered battery cells can be transferred to a plurality of battery cells (C1-C) included in the battery module (210). N It can be charged in ). Next, as illustrated in FIG. 6, the control circuit (240) allows the cell balancing circuit (230) to discharge the battery module (210). i) can be controlled (S610). The energy of the discharged battery module (210) is used to control the corresponding odd-numbered battery cell (C 2i As it is transferred to the battery cell (C1-C N To make the voltage of the battery cells (C1-C) uniform, N ) can be charged (S620). In some embodiments, the battery cell (C 2i When ) is discharged, the cell balancing circuit (230 i ) DC / DC converter (231 2i ) operates in dual-input single-output boost mode, and the battery cell (C 2i When ) is charged, the DC / DC converter (231 i ) can operate in single-input dual-output buck mode.

[0041] In FIGS. 3 to 6, the odd-numbered battery cells (C1, C3, C N-1 Among ) battery cells (C 2i-1 ) even-numbered battery cells (C2, C4, C N Among ) battery cells (C 2i Although ) was illustrated as a representative example, the battery cell (C 2i-1 When ) is balanced, the remaining odd-numbered battery cells are also balanced simultaneously, and battery cell (C 2i When ) is balanced, the remaining even-numbered battery cells can also be balanced at the same time.

[0042] In some embodiments, the control circuit (240) may be a processor of the battery management system (e.g., 123 in FIG. 1). In some embodiments, the battery monitoring circuit (220) may operate as the control circuit (240).

[0043] As explained above, the odd-numbered battery cell (C 2i-1 ) and even-numbered battery cells (C 2i ) is a DC / DC converter (231 i Sharing ), and odd-numbered battery cells (C 2i-1 While balancing ), the even-numbered battery cell (C2i Without balancing ), the even-numbered battery cell (C 2i While balancing ), the odd-numbered battery cell (C 2i-1 By not balancing ), the DC / DC converter (231 i By reducing the number of ), the unit cost and size of the battery management system can be reduced. In some embodiments, battery cells (C 2i-1 or C 2i After charging the entire battery module (210) with the energy discharged from the battery module (210), the battery cell (C) is charged with the energy charged in the battery module (210). 2i-1 or C 2i By recharging the battery, the voltage can be made uniform across multiple battery cells.

[0044] FIG. 7 is a diagram showing a cell balancing circuit according to a certain embodiment.

[0045] Referring to FIG. 7, the cell balancing circuit (700) may include a DC / DC converter (710) in the form of a boost converter. The cell balancing circuit (700) may include a plurality of battery cells (e.g., C1-C of FIG. 2). N The corresponding odd-numbered battery cell among ) (e.g., C 2i-1 ) and the corresponding even-numbered battery cell (e.g., C 2i Connected to ), battery cell (C 2i-1 , C 2i It can control the balancing of ).

[0046] The DC / DC converter (710) may include an inductor (711), switches (712, 713), and a capacitor (714). The inductor (711) may be connected between the input terminal (IN) of the DC / DC converter (710) and a node (N1). For example, a first terminal of the inductor (711) may be connected to the input terminal (IN), and a second terminal of the inductor (711) may be connected to the node (N1). The switch (712) may be connected between the node (N1) and the ground terminal, and the switch (713) may be connected between the node (N1) and the output terminal (OUT) of the DC / DC converter (710). In some embodiments, the switches (712, 713) may each be transistors. For example, the switches (712, 713) may each be n-channel field effect transistors (FETs). In this case, the drain of the FET (712, 713) may be connected to the node (N1), the source of the FET (712) may be connected to the ground terminal, and the source of the FET (713) may be connected to the output terminal (OUT). The switches (712, 713) may be controlled by a control circuit (e.g., 240 in FIG. 2). In some embodiments, the cell balancing circuit (700) may further include a driver (715) that drives the switches (712, 713) under the control of the control circuit (240). A capacitor (714) may be connected between the output terminal (OUT) and the ground terminal. For example, a first terminal of the capacitor (714) may be connected to the output terminal (OUT), and a second terminal of the capacitor (714) may be connected to the ground terminal. The output terminal (OUT) may be connected to the positive terminal of the battery module (e.g., 210 in FIG. 2).

[0047] The cell balancing circuit (700) is an odd-numbered battery cell (C 2i-1 A switch (721) connected between the negative terminal and the ground terminal of ), odd-numbered battery cells (C 2i-1A switch (722) connected between the positive electrode of ) and the input terminal (IN) of the DC / DC converter (710), and an even-numbered battery cell (C 2i A switch (723) connected between the negative electrode and the ground terminal of ) and an even-numbered battery cell (C 2i It may further include a switch (724) connected between the positive terminal of the DC / DC converter (710) and the input terminal (IN).

[0048] Odd-numbered battery cells (C 2i-1 When balancing ), the control circuit (240) states that the voltage of the battery module (210) is the battery cell (C 2i-1 Since the voltage is higher than that of ), the DC / DC converter (710) can be operated in boost mode first. In response to the control of the control circuit (240), switches (721, 722) are turned on, and the switch (712) of the DC / DC converter (710) can be turned on. In this case, switches (723, 724, 713) may be in the off state. Then the battery cell (C 2i-1 As the battery cell (C) is discharged, current is supplied to the inductor (711), and the current in the inductor (711) can increase. Next, in response to the control of the control circuit (240), the switch (712) of the DC / DC converter (710) can be turned off and the switch (713) can be turned on. Then, the battery cell (C) is energized by the energy charged in the inductor (711). 2i-1 The voltage of ) is discharged so that the battery module (210) can be charged.

[0049] Next, the control circuit (240) operates the DC / DC converter (710) in buck mode to transfer energy from the battery module (210) to the odd-numbered battery cell (C 2i-1It can be discharged by ). In response to the control of the control circuit (240), switches (721, 722) can be turned on and switch (713) of the DC / DC converter (710) can be turned on. In this case, switches (723, 724, 712) may be in an off state. Then, as the battery module (210) is discharged, the current in the inductor (711) may increase. In some embodiments, the current may flow through the body diode of the switch (713). Next, in response to the control of the control circuit (240), switch (713) of the DC / DC converter (710) can be turned off and switch (712) can be turned on. Then, the battery cell (C) is discharged by the energy charged in the inductor (711). 2i-1 ) can be charged. In some embodiments, current can flow through the body diode of the switch (712).

[0050] Even-numbered battery cells (C 2i When balancing ), the odd-numbered battery cell (C 2i-1 Similar to the balancing of ), the control circuit (240) can first operate the DC / DC converter (710) in boost mode. In response to the control of the control circuit (240), switches (723, 724) are turned on, and the switch (712) of the DC / DC converter (710) can be turned on. In this case, switches (721, 722, 713) may be in the off state. Then the battery cell (C 2i As the battery cell (C) is discharged, current is supplied to the inductor (711), and the current in the inductor (711) can increase. Next, in response to the control of the control circuit (240), the switch (712) of the DC / DC converter (710) can be turned off and the switch (713) can be turned on. Then, the battery cell (C) is energized by the energy charged in the inductor (711). 2i The voltage of ) is discharged so that the battery module (210) can be charged.

[0051] Next, the control circuit (240) can operate the DC / DC converter (710) in buck mode to discharge the energy of the battery module (210) to the even-numbered battery cells. In response to the control of the control circuit (240), switches (723, 724) can be turned on, and switch (713) of the DC / DC converter (710) can be turned on. In this case, switches (721, 722, 712) can be in the off state. Then, as the battery module (210) is discharged, the current of the inductor (711) can increase. Next, in response to the control of the control circuit (240), switch (713) of the DC / DC converter (710) can be turned off and switch (712) can be turned on. Then, the battery cell (C) is discharged by the energy charged in the inductor (711). 2i ) can be charged.

[0052] FIG. 8 is a diagram showing a cell balancing circuit according to a certain embodiment.

[0053] Referring to FIG. 8, the cell balancing circuit (800) may include a DC / DC converter (810) in the form of a buck-boost converter. The cell balancing circuit (800) may include a plurality of battery cells (e.g., C1-C of FIG. 2). N The corresponding odd-numbered battery cell among ) (e.g., C 2i-1 ) and the corresponding even-numbered battery cell (e.g., C 2i Connected to ), battery cell (C 2i-1 , C 2i It can control the balancing of ).

[0054] The DC / DC converter (810) may include an inductor (811), switches (812, 813, 814, 815), and a capacitor (816). The inductor (811) may be connected between a first node (N1) and a second node (N2). For example, a first terminal of the inductor (811) may be connected to the second node (N2), and a second terminal of the inductor (811) may be connected to the first node (N1). A switch (812) may be connected between the first node (N1) and a ground terminal, and a switch (813) may be connected between the first node (N1) and an output terminal (OUT) of the DC / DC converter (810). A switch (814) may be connected between an input terminal (IN) of the DC / DC converter (810) and a second node (N2), and a switch (815) may be connected between an input terminal (IN) and a ground terminal. In some embodiments, the switch (815) may be removed. In some embodiments, the switches (812, 813, 814, 815) may each be transistors. For example, the switches (812, 813, 814, 815) may each be n-channel FETs. In this case, the drain of the FET (812, 813) may be connected to a first node (N1), the source of the FET (814) and the drain of the FET (815) may be connected to an input terminal (IN), the drain of the FET (814) may be connected to a second node (N2), the source of the FET (812, 815) may be connected to a ground terminal, and the source of the FET (813) may be connected to an output terminal (OUT). Switches (812, 813, 814, 815) can be controlled by a control circuit (e.g., 240 in FIG. 2). In some embodiments, the cell balancing circuit (800) may further include a driver (817) that drives the switches (812, 813, 814, 815) under the control of the control circuit (240). A capacitor (816) may be connected between an output terminal (OUT) and a ground terminal. For example, a first terminal of the capacitor (816) may be connected to the output terminal (OUT), and a second terminal of the capacitor (816) may be connected to the ground terminal.The output terminal (OUT) can be connected to the positive terminal of the battery module (e.g., 210 in FIG. 2).

[0055] The cell balancing circuit (800) is for odd-numbered battery cells (C 2i-1 A switch (821) connected between the negative terminal and the ground terminal of ), odd-numbered battery cells (C 2i-1 A switch (822) connected between the positive electrode of ) and the input terminal (IN) of the DC / DC converter (810), and an even-numbered battery cell (C 2i A switch (823) connected between the negative terminal and the ground terminal of ) and an even-numbered battery cell (C 2i It may further include a switch (824) connected between the positive terminal of the DC / DC converter (810) and the input terminal (IN).

[0056] Odd-numbered battery cells (C 2i-1 When balancing ), the control circuit (240) ensures that the voltage of the battery module (210) is the battery cell (C 2i-1 Since the voltage is higher than that of ), the DC / DC converter (810) can be operated in boost mode first. In response to the control of the control circuit (240), switches (821, 822) are turned on, and switches (812, 814) of the DC / DC converter (810) can be turned on. In this case, switches (823, 824, 813, 815) may be in the off state. Then, the battery cell (C 2i-1 As the battery cell (C) is discharged, current is supplied to the inductor (811), and the current in the inductor (811) may increase. In some embodiments, the current may flow through the body diode of the switch (814). Next, in response to the control of the control circuit (240), the switch (812) of the DC / DC converter (810) may be turned off and the switch (813) may be turned on. Then, the battery cell (C) is energized by the energy charged in the inductor (811). 2i-1 The voltage of ) is discharged so that the battery module (210) can be charged.

[0057] Next, the control circuit (240) can operate the DC / DC converter (810) in buck mode to discharge the energy of the battery module (210) to the odd-numbered battery cells. In response to the control of the control circuit (240), switches (821, 822) can be turned on, and switches (813, 814) of the DC / DC converter (810) can be turned on. In this case, switches (823, 824, 812, 815) can be in an off state. Then, as the battery module (210) is discharged, the current of the inductor (811) can increase. In some embodiments, the current can flow through the body diode of the switch (813). Next, in response to the control of the control circuit (240), the switch (813) of the DC / DC converter (810) can be turned off and the switch (812) can be turned on. Then, the battery cell (C) is charged with energy in the inductor (811). 2i-1 ) can be charged. In some embodiments, current can flow through the body diode of the switch (812).

[0058] Even-numbered battery cells (C 2i When balancing ), the odd-numbered battery cell (C 2i-1 Similar to the balancing of ), the control circuit (240) can first operate the DC / DC converter (810) in boost mode. In response to the control of the control circuit (240), switches (823, 824) are turned on, and switches (812, 814) of the DC / DC converter (810) can be turned on. In this case, switches (821, 822, 813, 815) may be in the off state. Then the battery cell (C 2i As the battery cell (C) is discharged, current is supplied to the inductor (811), and the current in the inductor (811) can increase. Next, in response to the control of the control circuit (240), the switch (812) of the DC / DC converter (810) can be turned off and the switch (813) can be turned on. Then, the battery cell (C) is energized by the energy charged in the inductor (811). 2iThe voltage of ) is discharged so that the battery module (210) can be charged.

[0059] Next, the control circuit (240) can operate the DC / DC converter (810) in buck mode to discharge the energy of the battery module (210) to the even-numbered battery cells. In response to the control of the control circuit (240), switches (823, 824) can be turned on, and switches (813, 814) of the DC / DC converter (810) can be turned on. In this case, switches (821, 822, 812, 815) can be in the off state. Then, as the battery module (210) is discharged, the current of the inductor (811) can increase. Next, in response to the control of the control circuit (240), switch (813) of the DC / DC converter (810) can be turned off and switch (812) can be turned on. Then, the battery cell (C) is discharged by the energy charged in the inductor (811). 2i ) can be charged.

[0060] FIG. 9 is a flowchart illustrating a balancing method according to a certain embodiment.

[0061] Referring to FIG. 9, the control circuit of the battery management system can charge the battery module by operating the DC / DC converter in boost mode to discharge one of the groups of odd-numbered battery cells and even-numbered battery cells (e.g., the group of odd-numbered battery cells) (S910). The control circuit can charge the odd-numbered battery cells by operating the DC / DC converter in buck mode to discharge the battery module (S920).

[0062] The control circuit can charge the battery module by operating the DC / DC converter in boost mode to discharge the other group among the odd-numbered battery cell group and the even-numbered battery cell group (e.g., the even-numbered battery cell group) (S930). The control circuit can charge the even-numbered battery cell by operating the DC / DC converter in buck mode to discharge the battery module (S940).

[0063] Although embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims also fall within the scope of the present invention.

Claims

1. A battery management system connected to a battery module including multiple battery cells, Multiple cell balancing circuits, and It includes a control circuit that controls the plurality of cell balancing circuits above, and Each cell balancing circuit is A direct (DC) / DC converter in which the corresponding odd-numbered battery cell and the corresponding even-numbered battery cell among the plurality of battery cells share, and the output terminal is connected to the positive terminal of the battery module. A first switch connected between the corresponding odd-numbered battery cell and the input terminal of the DC / DC converter, and A second switch connected between the corresponding even-numbered battery cell and the input terminal. A battery management system including 2. In Paragraph 1, The first switch includes a switch connected between the positive electrode of the corresponding odd-numbered battery cell and the input terminal, and a switch connected between the negative electrode of the corresponding odd-numbered battery cell and the ground terminal. The second switch comprises a switch connected between the positive electrode of the corresponding even-numbered battery cell and the input terminal, and a switch connected between the negative electrode of the corresponding even-numbered battery cell and the ground terminal. Battery management system.

3. In Paragraph 1, A battery management system in which the above control circuit balances one of the corresponding odd-numbered battery cells and the corresponding even-numbered battery cells through the above DC / DC converter, and then balances another battery cell.

4. In Paragraph 3, The above control circuit is When balancing the corresponding odd-numbered battery cells, the first switch is turned on and the second switch is turned off, and Turning on the second switch and turning off the first switch when balancing the corresponding even-numbered battery cells. Battery management system.

5. In Paragraph 3, The above control circuit is When balancing the corresponding odd-numbered battery cells, the DC / DC converter is operated in boost mode and then operated in buck mode, When balancing the corresponding even-numbered battery cells, the DC / DC converter is operated in boost mode and then operated in buck mode. Battery management system.

6. In Paragraph 3, When balancing the corresponding odd-numbered battery cell, the DC / DC converter discharges the odd-numbered battery cell to charge the battery module, and then discharges the battery module to charge the odd-numbered battery cell. When balancing the corresponding even-numbered battery cells, the DC / DC converter discharges the even-numbered battery cells to charge the battery module, and then discharges the battery module to charge the even-numbered battery cells. Battery management system.

7. In Paragraph 1, The above DC / DC converter is An inductor connected between the above input terminal and the node, A third switch connected between the above node and the ground terminal, A fourth switch connected between the above node and the above output terminal, and A capacitor connected between the above output terminal and the ground terminal A battery management system including 8. In Paragraph 7, The above control circuit during balancing The operation of turning on the third switch and turning off the fourth switch, and then turning off the third switch and turning on the fourth switch, and After turning off the third switch and turning on the fourth switch The operation of turning on the third switch and turning off the fourth switch. A battery management system that performs the following in sequence.

9. In Paragraph 1, The above DC / DC converter is An inductor connected between the first node and the second node, A third switch connected between the first node and the ground terminal, A fourth switch connected between the first node and the output terminal, A fifth switch connected between the second node and the input terminal, and A capacitor connected between the above output terminal and the ground terminal A battery management system including 10. In Paragraph 9, The above control circuit during balancing The operation of turning on the third and fifth switches and turning off the fourth switch, then turning off the third switch and turning on the fourth and fifth switches, and After turning off the third switch and turning on the fourth and fifth switches The operation of turning on the third and fifth switches and turning off the fourth switch. A battery management system that performs the following in sequence.

11. A battery module comprising multiple battery cells, Multiple cell balancing circuits, and It includes a control circuit that controls the plurality of cell balancing circuits above, and Each cell balancing circuit includes a DC / DC converter whose output terminal is connected to the positive terminal of the battery module and which is shared by a corresponding odd-numbered battery cell and a corresponding even-numbered battery cell among the plurality of battery cells; and, in response to the control of the control circuit, balances one of the odd-numbered battery cell and the even-numbered battery cell through the DC / DC converter, and then balances the other battery cell. Battery device.

12. In Paragraph 11, The above control circuit is When balancing the odd-numbered battery cells, the DC / DC converter is operated in boost mode and then operated in buck mode, When balancing the even-numbered battery cells, the DC / DC converter is operated in boost mode and then operated in buck mode. Battery device.

13. In Paragraph 11, When balancing the odd-numbered battery cells, the DC / DC converter discharges the odd-numbered battery cells to charge the battery module, and then discharges the battery module to charge the odd-numbered battery cells. When balancing the even-numbered battery cells, the DC / DC converter discharges the even-numbered battery cells to charge the battery module, and then discharges the battery module to charge the even-numbered battery cells. Battery device.

14. A method for balancing a battery module comprising a plurality of battery cells, wherein A step of charging the battery module by discharging the odd-numbered group of battery cells among the plurality of battery cells, After discharging the odd-numbered battery cell group, the step of discharging the battery module to charge the odd-numbered battery cell group, A step of charging the battery module by discharging an even-numbered group of battery cells among the plurality of battery cells, and After discharging the even-numbered battery cells, the step of discharging the battery module to charge the even-numbered battery cell group A balancing method including 15. In Paragraph 14, One odd-numbered battery cell among the odd-numbered battery cell groups and one even-numbered battery cell among the even-numbered battery cell groups corresponding to the odd-numbered battery cell share one DC / DC converter, and The step of discharging the odd-numbered battery cell group includes the step of operating the DC / DC converter in boost mode, and The step of discharging the even-numbered battery cell group includes the step of operating the DC / DC converter in boost mode, The step of discharging the battery module includes the step of operating the DC / DC converter in buck mode. Balancing method.

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