Balance control system and balance control method for vehicle battery module

Abstract

The invention relates to a balance control system and a balance control method for a vehicle battery module. A balance control system for a battery module includes a plurality of battery modules each including a battery outputting a battery voltage, a first DC / DC converter connected in parallel with the battery, and an inverter converting the battery voltage into an AC module voltage and outputting the AC module voltage, and a controller, the controller controls each of the plurality of battery modules. First DC / DC converters included in the plurality of battery modules are connected in parallel with each other, and the controller is configured to monitor a battery state including at least one of a state of charge of the battery or a battery voltage, and control the first DC / DC converters to an on state or an off state based on the battery state.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0119163 filed on September 7, 2023, in the Korean Intellectual Property Office, and Korean Patent Application No. 10-2024-0115691 filed on August 28, 2024, in the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to a balance control system and a balance control method for a battery module of a vehicle. Background Art

[0004] Recently, as concerns about issues such as energy efficiency, environmental pollution, depletion of fossil fuels, etc. have increased, research and development of environmentally friendly vehicles that can actually replace internal combustion engine vehicles are being actively conducted.

[0005] Such environmentally friendly vehicles may include battery electric vehicles (BEV) that use batteries as a power source (electricity source), fuel cell electric vehicles (FCEV) that use fuel cells as a main power source, hybrid electric vehicles (HEV) that use an engine and a motor together as a driving device to drive the vehicle, etc.

[0006] The above-mentioned environmentally friendly vehicles can be broadly referred to as electric vehicles (xEVs), and what they have in common is that they can be motor-driven vehicles and electric vehicles that drive the motor with electricity from a high-voltage power source such as a battery or a fuel cell.

[0007] On the other hand, a high-voltage battery pack formed of a plurality of battery cells may have performance differences due to degradation differences between the battery cells depending on battery use. At this time, differences in internal resistance are generated due to performance differences between the battery cells, and differences in voltage are generated between the battery cells during charging / discharging. When voltage differences are generated between the battery cells in this way, the charging time of the battery increases, and the driving time or distance is shortened. Summary of the invention

[0008] One aspect of the present invention is to improve battery charging / discharging efficiency by performing balancing control that maintains a deviation in state-of-charge (SoC) between a plurality of battery modules configured by a series / parallel combination of a plurality of battery modules operating at a low voltage within a specific range.

[0009] Furthermore, an aspect of the present invention is to perform active balancing control by controlling an on / off switch of a converter included in each battery module for balancing control.

[0010] The purpose of the present invention is not limited to the above-mentioned tasks, and other tasks not mentioned will be clearly understood by ordinary technicians through the following description.

[0011] In order to achieve the above objectives, the present invention provides the following balancing control system and balancing control method for a battery module.

[0012] According to one aspect of the present invention, a balancing control system for a battery module includes a plurality of battery modules and a controller, wherein the plurality of battery modules respectively include a battery that outputs a battery voltage, a first DC / DC converter connected in parallel to the battery, and an inverter that converts the battery voltage into an AC module voltage and outputs the AC module voltage, wherein the controller controls each battery module of the plurality of battery modules, wherein the first DC / DC converters included in the plurality of battery modules are connected in parallel to each other, and the controller is configured to monitor a battery status including at least one of a battery state of charge (SoC) or a battery voltage, and control the first DC / DC converter to an ON state or an OFF state based on the battery status.

[0013] According to another aspect of the present invention, a balancing control method for multiple battery modules is provided, each battery module including a battery, a first DC / DC converter connected in parallel to the battery, and an inverter, the method comprising: monitoring the state of charge (SoC) of each battery included in the multiple battery modules; and controlling the first DC / DC converter to an ON state or an OFF state based on the SoC. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The above and other aspects, features and advantages of the present invention will be more clearly understood from the following detailed description presented in conjunction with the accompanying drawings, in which:

[0015] Figure 1 An electric vehicle drive system including a conventional high voltage battery pack is shown.

[0016] Figure 2 and Figure 3 A battery module according to an embodiment of the present invention is shown.

[0017] Figure 4 is a schematic diagram illustrating a connection structure between a plurality of battery modules according to an embodiment of the present invention.

[0018] Figure 5 A single-phase battery system according to an embodiment of the present invention is shown.

[0019] Figure 6is a schematic diagram showing a connection relationship of inverters in a three-phase battery system according to an embodiment of the present invention.

[0020] Figure 7 is a schematic diagram showing a connection relationship of a first DC / DC converter in a three-phase battery system according to an embodiment of the present invention.

[0021] Figure 8 is a schematic diagram showing a connection relationship of a second DC / DC converter in a three-phase battery system according to an embodiment of the present invention.

[0022] Fig. 9 is a schematic diagram showing a structure of an inverter according to an embodiment of the present invention.

[0023] Fig.10 is a flowchart of a balancing control method of a battery module according to an embodiment of the present invention.

[0024] Fig.11 is a flowchart of a balancing control method of a battery module according to an embodiment of the present invention.

[0025] Fig.12 is a block diagram of a computing device that can fully or partially implement a battery module balancing control system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] In the following, specific embodiments of the present invention will be described with reference to the accompanying drawings. The following detailed description is provided to help fully understand the methods, devices and / or systems described in this specification. However, the detailed description is only for illustrative purposes and the present invention is not limited thereto.

[0027] When describing an embodiment of the present invention, when determining that the detailed description of the known technology related to the present invention may unnecessarily obscure the main idea of ​​the present invention, its detailed description will be omitted. In addition, the term to be described later is a term limited by considering the function in the present invention, which can change according to the intention or habit of the user or operator. Therefore, these terms should be limited based on the content in this specification. The term used herein is only used to describe the purpose of a specific embodiment and does not limit the embodiment. As used herein, the singular form is intended to also include the plural form, unless the context clearly indicates otherwise. As used herein, when using the term "including", "containing", "having" etc. in this specification, it is indicated that there are described features, numerical values, steps, operations, elements, components or combinations thereof, but does not exclude the existence or addition of one or more other features, numerical values, steps, operations, elements, components and / or its groups.

[0028] In addition, as described below, a “module voltage” may refer to a voltage output from a battery module, and a “system voltage” may refer to a voltage output from a battery system configured based on a battery module.

[0029] The battery module described below may include a battery module for a vehicle, and the battery system may include a single-phase battery system for a vehicle and a three-phase battery system for a vehicle, or a battery module balancing control system.

[0030] Furthermore, the present invention can be used in various devices and vehicles applicable to a battery module and a battery system.

[0031] Figure 1 An electric vehicle drive system including a conventional high voltage battery pack is shown.

[0032] refer to Figure 1 The electric vehicle driving system 1 may include a conventional high-voltage battery pack 11 and various power conversion devices 12 .

[0033] In this case, the conventional high-voltage battery pack 11 may be configured by a series / parallel combination of a plurality of battery cells, and may not include a separate power conversion device. In addition, the conventional high-voltage battery pack 11 may output a high voltage having a single size (e.g., 480V to 806.4V). In addition, the power conversion device 12 may be disposed in a separate space separated from the high-voltage battery pack 11, and the high-voltage battery pack 11 and the power conversion device 12 may be connected by a high-voltage cable.

[0034] An electric vehicle may have electric field loads with various functions, and since the magnitude and type of voltage required by each electric field load may be different, various types of power conversion devices 12 may be required. According to the electric vehicle drive system 1 including the conventional high-voltage battery pack 11, since the electric vehicle drive system 1 is based on a single high voltage, a high-voltage power conversion device 12 should be used.

[0035] More specifically, the electric vehicle drive system 1 can convert the high voltage output from the conventional high-voltage battery pack 11 into a DC low voltage to provide a driving voltage to the low-voltage load R1 or charge the low-voltage battery. In this case, energy loss may occur in the process of converting power from the high voltage to the low voltage, which may reduce efficiency, and since the voltage should be significantly reduced, a separate transformer may be additionally required. In addition, the electric vehicle drive system 1 can convert the voltage output from the conventional high-voltage battery pack 11 to provide a driving voltage to the high-voltage load R2, and can form a high-voltage three-phase alternating current to provide a driving voltage to the motor M. In this case, the SiC power semiconductor used for the high-voltage switch can be generally used as an inverter operating at a high voltage, but the yield of the SiC power semiconductor may be low compared to the high demand, making it difficult to smoothly supply and request current, and its relatively high price may increase production costs.

[0036] In addition, the electric vehicle drive system 1 may have a separate structure in which the high-voltage battery pack 11 and the power conversion device are each separated, each of which may occupy a separate space, and a high-voltage cable should be used to connect them, which may occupy a large volume. In addition, the electric vehicle drive system 1 may generate a large amount of heat due to the high-voltage output of the high-voltage battery pack 11, and a water cooling system may be required to control the heat, which may occupy a large volume and be relatively heavy.

[0037] Furthermore, according to the electric vehicle driving system 1 , since specifications thereof are different according to the type of vehicle, a battery system should be individually designed according to the specifications of the type of vehicle, which may complicate the process and increase production costs.

[0038] The battery system according to an embodiment of the present invention described below may be configured by a series / parallel combination of a plurality of battery modules, and each of the battery modules may include a low voltage battery and a power conversion device such as an inverter, a converter, etc. operating at a low voltage.

[0039] For example, since the battery system according to an embodiment of the present invention can be configured based on a battery module, and each battery module may include a power conversion device, the battery system can store / release electrical energy and perform power conversion in the battery module. Therefore, the battery module according to an embodiment of the present invention can convert direct current into alternating current or convert the size of the battery power and output the battery power as needed. In addition, the output of each battery module can be connected in series to form a high voltage output, or can be connected in parallel to form a high current output, and the voltage of each battery module can be monitored to perform balancing control. Hereinafter, the battery module according to an embodiment of the present invention and the battery system including the battery module will be described in more detail.

[0040] Figure 2 A battery module according to an embodiment of the present invention is shown.

[0041] refer to Figure 2 , a battery module 10 according to an embodiment of the present invention may include: a battery 110 , an inverter 120 , a first DC / DC converter 130 and a second DC / DC converter 140 .

[0042] The battery 110 may output a battery voltage and may charge or discharge electric energy. In addition, the battery voltage may constitute a reference voltage of the battery module 10 to provide an input voltage to the inverter 120 , the first DC / DC converter 130 , and the second DC / DC converter 140 .

[0043] In addition, the battery 110 may have a size ratio Figure 1 The conventional high voltage battery pack 11 described in FIG. 1 is smaller in size than the battery voltage. Therefore, since the battery module 10 for a vehicle according to the embodiment of the present invention can apply a power conversion device capable of operating at a low voltage, the manufacturing cost can be reduced.

[0044] According to the battery module 10 according to the embodiment of the present invention, various sizes and types of voltages can be output according to the series / parallel combination of the battery modules 10. Therefore, the battery module 10 can be applied to various vehicles of various specifications using a single specification of the battery module 10, and the manufacturing cost can be reduced.

[0045] For example, when the battery voltage is set to 100 V, a battery system that outputs a voltage of 400 V can be formed by connecting four battery modules 10 in series, and a battery system that outputs a voltage of 800 V can be formed by connecting eight battery modules 10 in series. In addition, for example, when the battery voltage is set to 50 V, a battery system that outputs a voltage of 400 V can be formed by connecting eight battery modules 10 in series, and a battery system that outputs a voltage of 800 V can be formed by connecting 16 battery modules 10 in series.

[0046] In addition, a single-phase battery system that outputs a high-voltage AC voltage can be configured by connecting the battery modules 10 in series and using an inverter output, and a three-phase AC voltage can be output by using multiple single-phase battery systems. In addition, a battery system through which a high current flows can be formed by combining the battery modules 10 in parallel.

[0047] The inverter 120 can convert the battery voltage into an AC module voltage, and can output the AC module voltage. In addition, the inverter 120 may include an input terminal and an output terminal, and the inverter input terminal may be connected in parallel to the battery to receive the battery voltage, and the inverter output terminal may output the AC module voltage. In addition, hereinafter, the inverter output terminal may be referred to as an AC module output terminal that outputs the AC module voltage. In addition, the inverter 120 may be configured to supply the AC power according to the AC module voltage to the AC load. In this case, the AC load may be a load (e.g., a motor, etc.) that uses an AC voltage as a driving voltage.

[0048] In addition, the first DC / DC converter 130 may convert the battery voltage into a first DC module voltage which is lower than the battery voltage, and may output the first DC module voltage.

[0049] The first DC module voltage can be set to a driving voltage of a low-voltage load. For example, the low-voltage load can be an electric field load such as various lights, radios, and infotainment systems of electric vehicles. The first DC module voltage can be set to a driving voltage of a low-voltage load such as 12V, 24V, 48V, etc. The magnitude of the voltage mentioned in this specification may only be an implementation scheme, and can be set to voltages of various magnitudes according to the design.

[0050] The first DC / DC converter may include input terminals 130a and 130b and output terminals 130c and 130d, and the input terminals 130a and 130b of the first DC / DC converter may be connected in parallel to the battery to receive the battery voltage, and the output terminals 130c and 130d of the first DC / DC converter may output the first DC module voltage. Hereinafter, the output terminals 130c and 130d of the first DC / DC converter may also be referred to as first DC module output terminals outputting the first DC module voltage.

[0051] In addition, the output terminals 130 c and 130 d of the first DC / DC converter may be directly connected to a low voltage load to provide a first DC block voltage.

[0052] In an embodiment, one end 130d of the output terminal of the first DC / DC converter can be grounded, and the other end 130c can be connected to a low voltage load to output the first DC module voltage. In another embodiment, both ends of the output terminal of the first DC / DC converter can be connected to both ends of the low voltage load to output the first DC module voltage.

[0053] The second DC / DC converter 140 may convert the battery voltage into a second DC module voltage and may output the second DC module voltage. The second DC module voltage may be set to a value greater than the first DC module voltage output from the first DC / DC converter 130. The second DC module voltage may be less than or equal to the battery voltage and may be greater than the battery voltage.

[0054] In addition, the second DC module voltage output from the second DC / DC converter 140 can be connected in series with the second DC module voltage output from a different battery module 10 to provide power to a high-voltage load. For example, the second DC module voltage output from the second DC / DC converter 140 may not be used as a single output to provide power to a high-voltage load, but may be connected in series with the second DC module voltage of a different battery module 10 to provide power to a high-voltage load. Since the battery voltage included in the battery module 10 can be configured as a low voltage, a plurality of battery modules 10 can be combined in series to provide a high voltage, thereby providing voltage to a high-voltage load such as an air conditioning system. For example, the output terminal of the second DC / DC converter can be connected in series with the output terminal of the second DC / DC converter of another battery module to form a high voltage, and power can be provided to a high-voltage load.

[0055] In addition, the second DC / DC converter may include input terminals 140a and 140b and output terminals 140c and 140d, the input terminals 140a and 140b of the second DC / DC converter may be connected in parallel to the battery 110 to receive the battery voltage, and the output terminals 140c and 140d of the second DC / DC converter may output the second DC module voltage. In addition, in this specification, the output terminals 140c and 140d of the second DC / DC converter may also be referred to as second DC module output terminals that output the second DC module voltage.

[0056] In addition, the output terminals 140c and 140d of the second DC / DC converter may be connected in series with the output terminals of the second DC / DC converter included in the different battery modules, or may be connected to a high voltage load. In this case, a specific connection structure with different battery modules 10 will be described later. The battery 110 may be configured to be connected in parallel with the input terminals 120a and 120b of the inverter, the input terminals 130a and 130b of the first DC / DC converter, and the input terminals 140a and 140b of the second DC / DC converter.

[0057] Figure 3 A battery module according to an embodiment of the present invention is shown.

[0058] refer to Figure 3The battery module 20 according to the embodiment of the present invention may include a battery 210, an inverter 220, a first DC / DC converter 230, a second DC / DC converter 240, and a common capacitor 250. The common capacitor 250 may be connected to the battery 210 in parallel. Figure 3 The battery module 20 shown in FIG. 1 may include Figure 2 All configurations of the battery module 10 are shown, and may further include a common capacitor 250 .

[0059] According to the battery module 20 according to the embodiment of the present invention, since a common capacitor can be shared without applying a separate capacitor to each inverter and converter device, the volume can be reduced, and since a low-voltage capacitor can be applied, the production cost can be reduced.

[0060] Figure 4 is a schematic diagram illustrating a connection structure between a plurality of battery modules according to an embodiment of the present invention.

[0061] refer to Figure 4 , the first battery module 10-1 and the second battery module 10-2 may include the same configuration and may be configured to have the same structure. Figure 2 As described above, the first battery module 10-1 and the second battery module 10-2 may include: batteries 110-1 and 110-2, inverters 120-1 and 120-2, first DC / DC converters 130-1 and 130-2, and second DC / DC converters 140-1 and 140-2, respectively. Figure 3 As mentioned above, the first battery module 10 - 1 and the second battery module 10 - 2 may further include a common capacitor.

[0062] In addition, a plurality of battery modules may be connected to configure a battery system, and a connection relationship between the plurality of battery modules included in the battery system may be the same as Figure 4 The structures shown are the same.

[0063] More specifically, the output terminals 120-1c and 120-1d of the inverter included in the first battery module 10-1 can be connected in series with the output terminals 120-2c and 120-2d of the inverter included in the second battery module 10-2. When the inverter outputs the AC module voltage, the inverter 120-1 included in the first battery module and the inverter 120-2 included in the second battery module can be connected in series to output an AC module voltage twice the size. For example, when the AC module voltage is set to 100V, the two inverters 120-1 and 120-2 connected in series can output an AC voltage of 200V. In this case, the magnitude of the AC voltage can represent the maximum value, effective value, or average value of the AC voltage.

[0064] The output terminals 130-1c and 130-1d of the first DC / DC converter included in the first battery module 10-1 and the output terminals 130-2c and 130-2d of the first DC / DC converter included in the second battery module 10-2 can be connected in parallel. In the embodiment, one end 130-1d of the first DC / DC converter included in the first battery module 10-1 can be grounded, and one end 130-2d of the output terminal of the first DC / DC converter included in the second battery module 10-2 can be grounded. The other end 130-1c of the output terminal of the first DC / DC converter included in the first battery module 10-1 and the other end 130-2c of the output terminal of the first DC / DC converter included in the second battery module 10-2 can be connected in parallel to output the first DC module voltage. The output terminal at the other end of the output terminal of the first DC / DC converter can be connected in parallel to output the first DC module voltage, and the first DC module voltage can be used as a driving voltage to be connected to a low-voltage load to provide a voltage.

[0065] In addition, the output terminals 140-1c and 140-1d of the second DC / DC converter included in the first battery module 10-1 can be connected in series with the output terminals 140-2c and 140-2d of the second DC / DC converter included in the second battery module 10-2. More specifically, one end 140-1d of the output terminal of the second DC / DC converter included in the first battery module 10-1 can be connected to the other end 140-2c of the output terminal of the second DC / DC converter of the second battery module 10-2.

[0066] When the second DC / DC converter outputs the second DC module voltage, the second DC / DC converter 140-1 included in the first battery module and the second DC / DC converter 140-2 included in the second battery module can be connected in series to output a second DC module voltage twice as large. For example, when the second DC module voltage is set to 100V, the two second DC / DC converters 140-1 and 140-2 connected in series can output 200V.

[0067] In summary, in the first battery module 10 - 1 and the second battery module 10 - 2 , the inverters may be connected in series, the first DC / DC converters may be connected in parallel, and the second DC / DC converters may be connected in series.

[0068] Figure 5 A single-phase battery system according to an embodiment of the present invention is shown.

[0069] refer to Figure 5, the single-phase battery system 100 according to the embodiment of the present invention may include a plurality of battery modules 10-1, 10-2, ..., and 10-N. Each of the plurality of battery modules 10-1, 10-2, ..., and 10-N included in the single-phase battery system 100 may be connected to Figure 2 or Figure 3 The battery modules 10 and 20 shown in FIG. 1 are the same. In addition, the plurality of battery modules 10-1, 10-2, ..., 10-N included in the single-phase battery system 100 may have Figure 4 The connection structure between the battery modules shown.

[0070] Reference again Figure 3 , a battery module according to an embodiment of the present invention may include: first DC module output terminals 130c and 130d corresponding to the output terminals of the first DC / DC converter, second DC module output terminals 140c and 140d corresponding to the output terminals of the second DC / DC converter, and AC module output terminals 120c and 120d corresponding to the output terminals of the inverter.

[0071] refer to Figure 5 , the single-phase battery system 100 according to the embodiment of the present invention may include first DC system output terminals 130c and 130d, which are configured by connecting in parallel the first DC module output terminals included in each of the plurality of battery modules. In this case, the first DC system output terminals 130c and 130d may output a first DC system voltage, and the first DC system voltage may have the same magnitude as the first DC module voltage output from the output terminal of the first DC / DC converter.

[0072] The single-phase battery system 100 according to an embodiment of the present invention may include second DC system output terminals 140-1c and 140-Nd, which are configured by connecting in series the second DC module output terminals included in each of the plurality of battery modules. In this case, the second DC system output terminals 140-1c and 140-Nd may output a second DC system voltage, and the second DC system voltage may have a magnitude that may be an integer (N) times the second DC module voltage output from the output terminal of the second DC / DC converter.

[0073] In addition, the single-phase battery system 100 according to the embodiment of the present invention may include AC system output terminals 120-1c and 120-Nd, which are configured by connecting in series the AC module output terminals included in each battery module of the plurality of battery modules. In addition, the AC system output terminals 120-1c and 120-Nd can output an AC system voltage, and the AC system voltage can have a size that is an integer (N) times the AC module voltage output from the output terminal of the inverter. The AC system output terminal can provide AC power to an AC load, and can provide an input voltage for one phase of a three-phase AC voltage.

[0074] In summary, the single-phase battery system 100 can provide various output voltages including a first DC system voltage, a second DC system voltage, and an AC system voltage by connecting each device of a plurality of battery modules in series or in parallel.

[0075] The electric vehicle may include a low voltage load R1 operating at a low voltage, a high voltage load R2 operating at a high voltage, and an AC load (e.g., a motor M, etc.) operating at a high voltage three-phase AC voltage. In addition, the low voltage load may utilize the first DC system voltage as a driving voltage, the high voltage load may utilize the second DC system voltage as a driving voltage, and the AC load may utilize the AC system voltage as a driving voltage.

[0076] Figure 6 is a schematic diagram showing a connection relationship of inverters in a three-phase battery system 1000 according to an embodiment of the present invention. Figure 7 is a schematic diagram showing the connection relationship of the first DC / DC converter in the three-phase battery system according to an embodiment of the present invention. In addition, Figure 8 is a schematic diagram showing a connection relationship of a second DC / DC converter in a three-phase battery system according to an embodiment of the present invention.

[0077] refer to Figures 6 to 8 , the three-phase battery system 1000 according to the embodiment of the present invention may include a plurality of single-phase battery systems 100 - 1 , 100 - 2 , and 100 - 3 , and each of the single-phase battery systems may include a plurality of battery modules.

[0078] refer to Figure 6 , the three-phase battery system 1000 according to the embodiment of the present invention may include three single-phase battery systems 100-1, 100-2 and 100-3. In addition, the single-phase battery system may include an AC system output terminal configured by connecting the inverter output terminals in series. In addition, each of the AC system output terminals included in the three single-phase battery systems may output different AC voltages having the same magnitude and the same phase difference.

[0079] For example, each of the AC system output terminals included in the three single-phase battery systems can output different AC voltages with a phase difference of 120 degrees from each other. Therefore, the three-phase battery system can output a three-phase AC voltage, and the three-phase AC voltage can be used as a driving voltage to provide a driving voltage to the motor.

[0080] refer to Figure 7 , each of the plurality of single-phase battery systems 100-1, 100-2, and 100-3 included in the three-phase battery system 1000 according to the embodiment of the present invention may include a first DC system output terminal, wherein the plurality of first DC / DC converters are connected in parallel to each other to output a first DC system voltage. The first DC system output terminals included in each of the plurality of single-phase battery systems 100 may be connected in parallel to each other.

[0081] For example, when the single-phase battery system 100 includes N first DC / DC converters, all 3×N first DC / DC converters included in the three-phase battery system 1000 can be connected in parallel to output a first DC module voltage or a first DC system voltage having the same magnitude as the first DC module voltage.

[0082] In addition, reference Figure 8 , each of the multiple single-phase battery systems 100 included in the three-phase battery system 1000 according to the embodiment of the present invention may include a second DC system output terminal, wherein the multiple second DC / DC converters are connected in series to output a second DC system voltage. In addition, the second DC system output terminals included in each of the multiple single-phase battery systems may be connected in parallel to each other. For example, in the single-phase battery system 100, the second DC module output terminals may be connected in series to form the second DC system output terminals, and in the three-phase battery system 1000, each of the multiple second DC system output terminals may be connected in parallel to each other.

[0083] In addition, the three-phase battery system may further include a controller (not shown). The controller may control each battery module individually, and may control the inverter, the first DC / DC converter, and the second DC / DC converter included in each battery module individually. Therefore, according to an embodiment of the present invention, energy efficiency can be improved by performing balancing control on each power conversion device and each battery module.

[0084] Furthermore, when a problem occurs in some of the N battery modules, the controller may block only the battery module in which the problem occurs to ensure the reliability of the entire system.

[0085] Furthermore, since the controller can control each battery module individually, even when each battery module deteriorates to a different extent, the degradation performance of each battery module can be actively controlled.

[0086] Fig. 9 is a schematic diagram showing a structure of an inverter according to an embodiment of the present invention.

[0087] refer to Fig. 9 , the inverter 120 may include a plurality of silicon metal oxide semiconductor field effect transistor (Si-MOSFET) devices 1201 , 1202 , 1203 , and 1204 , and may be configured as an H-bridge single-phase inverter structure.

[0088] In conventional electric vehicle systems, SiC power semiconductors may be mainly applied. Such SiC power semiconductors may have high efficiency and fast switching speed, but may be expensive.

[0089] Additionally, conventional electric vehicle systems may sometimes use insulated gate bipolar transistors (IGBTs) at low voltages, which may be relatively inexpensive but may have slow switching speeds.

[0090] Si-MOSFET devices can have fast switching speeds and can be relatively inexpensive, but their performance deteriorates at high voltages, making them difficult to apply to conventional high-voltage electric vehicle systems.

[0091] Since the battery module according to the embodiment of the present invention is driven at a low voltage, the Si-MOSFET device can be applied to the inverter. Therefore, the inverter included in the battery module according to the embodiment of the present invention can use a plurality of Si-MOSFET devices to reduce production costs while having a fast switching speed. Therefore, the power efficiency can be improved to increase the vehicle mileage, and as the mileage increases, the battery capacity can be reduced to reduce production costs.

[0092] Furthermore, the inverter according to the embodiment of the present invention may be configured as an H-bridge single-phase inverter structure to maintain stability even at a large current.

[0093] In addition, although Fig. 9 A case where the H-bridge circuit is configured using four Si-MOSFETs is shown as an example, but the H-bridge circuit can also be configured by connecting a plurality of Si-MOSFETs in parallel to switch a large current.

[0094] In addition, according to an embodiment of the present invention, the battery system may include a plurality of battery modules and a controller. In addition, the controller may perform balancing control on each of the plurality of battery modules to maintain the state-of-charge (SoC) or voltage of the battery included in each of the plurality of battery modules within a specific deviation.

[0095] More specifically, the battery system according to an embodiment of the present invention can perform balancing control of the battery module by controlling the on / off switch of the first DC / DC converter included in the battery module. As described above, the first DC / DC converter can be a power conversion device that supplies the first DC module voltage to the low-voltage load of the vehicle. In addition, although the first DC / DC converters included in each battery module of the plurality of battery modules are all connected in parallel, in order to disconnect one of them and not supply power to the low-voltage load, the first DC module voltage can be provided to the low-voltage load by the remaining first DC / DC converters that are turned on.

[0096] Fig.10 is a flowchart of a balancing control method of a battery module according to an embodiment of the present invention.

[0097] refer to Fig.10 , the controller may monitor the SoC or battery voltage of the battery included in each of the plurality of battery modules ( S11 ).

[0098] The controller may determine whether the SoC or battery voltage of the battery is within a set range (S12). In this case, the value of the set range may be a specific value smaller than the reference value. The reference value may be an average value, a median value, or an average value of the highest and lowest values ​​of the SoC or battery voltage of the battery included in each battery module of the plurality of battery modules. The reference value may not be a fixed value, but may vary over time and may be a value that decreases according to the use of the battery system. In an embodiment, the reference value may be set to have a value of 1% to 2%.

[0099] When the controller determines that the SoC or battery voltage of the battery is within the set range, the controller can control the first DC / DC converter included in the corresponding battery module to have an ON state (S13). In addition, when the controller determines that the SoC or battery voltage of the battery is outside the set range, the controller can control the first DC / DC converter included in the corresponding battery module to have an OFF state (S14).

[0100] For example, when the average SoC value of multiple battery modules is 70% and a specific value is set to 1%, the first DC / DC converter of the battery module with a SoC less than 69% can be controlled to an OFF state, and the first DC / DC converter of the battery module with a SoC greater than 69% can be controlled to an ON state.

[0101] Alternatively, when the SoC average value of multiple battery modules is 70% and the specific value is set to 2%, the first DC / DC converter of the battery module with a SoC less than 68% can be controlled to an OFF state, and the first DC / DC converter of the battery module with a SoC greater than 68% can be controlled to an ON state.

[0102] For example, the battery system may include 24 battery modules, of which 22 battery modules may have a SoC of 75%, and 2 battery modules may have a SoC of 70%. Then, the first DC / DC converter of the two battery modules with a SoC of 70% may be controlled to an OFF state, and the first DC / DC converter of the 22 battery modules with a SoC of 75% may be controlled to an ON state. Then, over time, the two battery modules with a SoC of 70% may consume less power than different battery modules to reduce the SoC deviation between the battery modules. Thereafter, the controller may continuously monitor the SoC or battery voltage of the battery, and when the SoC of the battery module falls within a set range, for example, when the SoC of the battery module is a value that is a specific value less than a reference value, the first DC / DC converter may be converted to have an ON state.

[0103] In addition, when the first DC / DC converter is in the ON state, the first DC / DC converter can convert the battery voltage into a first DC module voltage which is lower than the battery voltage, and can provide the first DC module voltage to the low-voltage load of the vehicle.

[0104] When the first DC / DC converter is in the OFF state, the first DC / DC converter may not convert the battery voltage and may not provide power to the low-voltage load of the vehicle. Therefore, when the first DC / DC converter is in the OFF state, the consumption of the battery SoC may be less than when the first DC / DC converter is in the ON state.

[0105] By doing so, the controller can reduce the SoC deviation between the battery modules and can perform a certain level of balancing control by supplying power to the low-voltage loads of the vehicle only from the battery modules having a battery voltage or SoC greater than a set value.

[0106] In addition, as described above, the controller may be configured to perform a balancing control method for a battery module.

[0107] The controller can set the maximum number of the first DC / DC converter in the OFF state. In the case where the number of the first DC / DC converter in the OFF state is not set, the number of the first DC / DC converter in the OFF state may be excessively increased, and low-voltage power cannot be smoothly supplied to the low-voltage load. Therefore, the controller can smoothly supply power to the low-voltage load by setting the maximum number of the first DC / DC converter in the OFF state or the minimum number of the first DC / DC converter in the ON state. In an embodiment, the maximum number of the first DC / DC converter in the OFF state or the minimum number of the first DC / DC converter in the ON state can be set based on the number of low-voltage loads that need power. For example, the more low-voltage loads that can be set to need power, the smaller the maximum number of the first DC / DC converter in the OFF state. Alternatively, the fewer low-voltage loads that can be set to need power, the larger the maximum number of the first DC / DC converter in the OFF state.

[0108] Fig.11 is a flowchart of a balancing control method of a battery module according to an embodiment of the present invention.

[0109] refer to Fig.11 The controller may monitor at least one of the SoC or the battery voltage of the battery included in each battery module including the plurality of battery modules (S21). Then, the controller may determine whether the first DC / DC converter included in each battery module of the plurality of battery modules can be in the ON state (S22).

[0110] When the first DC / DC converter is in the ON state, the controller may determine whether the SoC of the battery module is less than a reference value by a first value (S23). In this case, the reference value may be an average value, a median value, or an average value of the highest and lowest values ​​of the SoC or battery voltage of the battery included in each battery module of the plurality of battery modules. In an embodiment, the first value may be an error range of the reference value and may be set to have an error range of 1% to 2%.

[0111] When the first DC / DC converter is in the ON state and the SoC of the battery module is less than the reference value by a first value, the controller may convert the first DC / DC converter in the ON state to the OFF state (S24). In addition, when the SoC of the battery module is not less than the reference value by a first value, the controller may keep the first DC / DC converter in the ON state (S25).

[0112] When the first DC / DC converter is in the OFF state, the controller may determine whether the SoC of the battery module is less than the reference value by a second value (S26). In this case, the second value may be a value less than the first value. The reference value may be an average value, a median value, or an average value of the highest and lowest values ​​of the SoC or battery voltage of the battery included in each battery module of the plurality of battery modules. In an embodiment, the second value may be set to have a value of 1% to 2%.

[0113] When the first DC / DC converter is in the OFF state and the SoC of the battery module is less than the reference value by a second value, the controller may maintain the first DC / DC converter in the OFF state (S27). When the first DC / DC converter is in the OFF state and the SoC of the battery module is not less than the reference value by a second value, the controller may switch the first DC / DC converter to the ON state (S28).

[0114] In an embodiment, the first value may be set to have 2%. When the SoC average value of the battery is 70% and the SoC value of the battery module including the first DC / DC converter in the ON state drops to 68% or less, the controller may switch the first DC / DC converter to the OFF state. When the SoC value of the battery module including the first DC / DC converter in the ON state does not drop to 68% or less, the controller may keep the first DC / DC converter in the ON state.

[0115] The second value may be set to have 1%. When the SoC of the battery module including the first DC / DC converter in the OFF state is 1% less than the reference value, the first DC / DC converter may maintain the OFF state. When the SoC value of the battery module including the first DC / DC converter in the OFF state is not less than 1% less than the reference value, the controller may switch the first DC / DC converter to the ON state.

[0116] For example, to switch the first DC / DC converter from the ON state to the OFF state, the controller may determine whether the SoC is less than a reference value by a first value. To switch the first DC / DC converter from the OFF state to the ON state, the controller may determine whether the SoC is less than a reference value by a second value.

[0117] When the first value and the second value are set equal to each other and the SoC of the battery oscillates around the reference value, the on / off switch of the first DC / DC converter may be frequently switched, which may cause unnecessary power consumption.

[0118] Therefore, the controller may set the criterion for transitioning from the ON state to the OFF state to be lower than the case of transitioning from the OFF state to the ON state, so as to maintain the ON state for a long time. The controller may set the criterion for transitioning from the OFF state to the ON state to be higher or looser than the case of transitioning from the ON state to the OFF state, so as to maintain the OFF state for a long time.

[0119] In addition, as described above, the controller may be configured to perform a balancing control method for a battery module.

[0120] Fig.12 is a block diagram of a computing device that can fully or partially implement a battery module balancing control system according to an embodiment of the present invention.

[0121] like Fig.12 As shown, computing device 1200 may include at least one processor 1201 , a computer-readable storage medium 1202 , and a communication bus 1203 .

[0122] The processor 1201 may enable the computing device 1200 to operate according to the exemplary embodiments mentioned above. For example, the processor 1201 may execute one or more programs stored in the computer-readable storage medium 1202. The one or more programs may include one or more computer-executable instructions, and the computer-executable instructions may be configured to enable the computing device 1200 to perform operations according to the exemplary embodiments when executed by the processor 1201. As described above, the processor 1201 may implement a controller.

[0123] The computer-readable storage medium 1202 may be configured to store computer-executable instructions or program codes, program data, and / or other suitable forms of information. The program 1202a stored on the computer-readable storage medium 1202 may include an instruction set executable by the processor 1201. In an embodiment, the computer-readable storage medium 1202 may be a memory (volatile memory, such as random access memory, non-volatile memory, or a suitable combination thereof), one or more magnetic disk storage devices, one or more optical disk storage devices, one or more flash memory devices, or any other form of storage medium that can be accessed by the computing device 1200 and can store the desired information, or a suitable combination thereof.

[0124] The communication bus 1203 may include the processor 1201 and the computer-readable storage medium 1202 to interconnect various other components of the computing device 1200 .

[0125] The computing device 1200 may also include one or more input / output interfaces 1205 and one or more network communication interfaces 1206 that provide interfaces for one or more input / output devices 1204. The input / output interface 1205 and the network communication interface 1206 may be connected to the communication bus 1203. The input / output device 1204 may be connected to other components of the computing device 1200 via the input / output interface 1205. Exemplary input / output devices 1204 may include input devices and / or output devices, such as a pointer device (mouse, touchpad, etc.), a keyboard, a touch input device (touchpad, touch screen, etc.), a voice input device, a sound input device, various types of sensor devices and / or a photographic device, and the output device may be a display device, a printer, a speaker and / or a network card. Exemplary input / output devices 1204 may be included in the computing device 1200 as a component constituting the computing device 1200, or may be connected to the computing device 1200 as a separate device distinguished from the computing device 1200.

[0126] Embodiments of the present invention may include a program for executing the method described in this specification on a computer and a computer-readable recording medium including the program. The computer-readable recording medium may include program commands, local data files, local data structures, etc., individually or in combination. The medium may be those specially designed and configured for the present invention, or may be those commonly used in the field of computer software. Examples of computer-readable recording media may include magnetic media, optical recording media, and hardware devices, such as hard disks, floppy disks, and tapes, and the optical recording media may be CD-ROMs and DVDs, and the hardware devices may be specially configured to store and execute program commands, such as ROMs, RAMs, and flash memories, etc. The above program examples may include not only machine language codes generated by, for example, a compiler, but also high-level language codes that can be executed by a computer using an interpreter, etc.

[0127] Although the representative embodiments of the present invention have been described in detail above, it will be appreciated by those skilled in the art that various modifications may be made to the above embodiments without departing from the scope of the present invention. Therefore, the scope of the rights of the present invention should not be limited to the described embodiments, but should be limited not only by the appended claims, but also by their equivalents.

[0128] According to an embodiment of the present invention, battery charging time is reduced and driving time or distance is increased by performing balancing control, which keeps the deviation of SoC between multiple battery modules configured by a series / parallel combination of multiple battery modules operating at low voltage within a specific range.

[0129] Furthermore, according to the embodiment of the present invention, active balancing control may be performed for balancing control by controlling the on / off switch of the converter included in each battery module by the controller.

[0130] While exemplary embodiments have been illustrated and described above, it will be apparent to those skilled in the art that modifications and variations may be made without departing from the scope of the invention as defined by the appended claims.

Claims

1. A balancing control system for a battery module, comprising: A plurality of battery modules, each battery module comprising a battery, a first DC / DC converter and an inverter, the battery outputting a battery voltage, the first DC / DC converter being connected in parallel to the battery, the inverter converting the battery voltage into an AC module voltage and outputting the AC module voltage; a controller configured to control each battery module of the plurality of battery modules; Wherein, the first DC / DC converters included in the plurality of battery modules are connected in parallel with each other; The controller is configured to monitor a battery status including at least one of a battery power status or a battery voltage, and control the first DC / DC converter to be in an on state or an off state based on the battery status.

2. The balancing control system for a battery module according to claim 1, wherein: The controller is configured as follows: Determine whether the battery status is within the set range; When the battery state is within a set range, controlling the first DC / DC converter to be in an on state; When the battery state is outside the set range, the first DC / DC converter is controlled to be in a disconnected state.

3. The balancing control system for a battery module according to claim 2, wherein: The setting range is set to a range not less than a value smaller than a reference value by a specific value.

4. The balancing control system for a battery module according to claim 1, wherein: The controller is further configured to: determining whether the first DC / DC converter is in an on state; When the first DC / DC converter is in an on state, determining whether the battery state is less than a reference value by a first value; When the battery state is less than the reference value by a first value, converting the on state of the first DC / DC converter into an off state; When the battery state is not less than the reference value by a first value, the first DC / DC converter is kept in the on state.

5. The balancing control system for a battery module according to claim 4, wherein: The controller is further configured to: determining whether the first DC / DC converter is in an on state; When the first DC / DC converter is in the disconnected state, determining whether the battery state is less than a reference value by a second value; When the battery state is less than the reference value by a second value, keeping the first DC / DC converter in a disconnected state; When the battery state is not less than the reference value by a second value, the off state of the first DC / DC converter is converted into the on state.

6. The balancing control system for a battery module according to claim 5, wherein: The second value is smaller than the first value.

7. The balancing control system for a battery module according to claim 3, wherein: The reference value is set to an average value, a median value, or an average value of the highest value and the lowest value of the battery states of the plurality of battery modules.

8. The balancing control system for a battery module according to claim 1, wherein: The first DC / DC converter is configured to convert a battery voltage into a first DC module voltage in an on state, and provide the first DC module voltage to a low-voltage load of the vehicle.

9. The balancing control system for a battery module according to claim 1, wherein: Each of the plurality of battery modules further includes a second DC / DC converter, which converts the battery voltage into a second DC module voltage and outputs the second DC module voltage.

10. The balancing control system for a battery module according to claim 9, wherein: The second DC / DC converters included in the plurality of battery modules are connected in series with each other.

11. The balancing control system for a battery module according to claim 1, wherein: The inverters included in the plurality of battery modules are connected in series with each other.

12. A balancing control method for a plurality of battery modules, each battery module comprising a battery, a first DC / DC converter connected in parallel to the battery, and an inverter, the method comprising: monitoring, by a controller, a battery status, the battery status comprising at least one of a charge state or a battery voltage of a battery included in each of the plurality of battery modules; The first DC / DC converter is controlled to be in an on state or an off state based on the battery state.

13. The balancing control method for multiple battery modules according to claim 12, wherein: Controlling the first DC / DC converter to be in an on state or an off state comprises: Determine whether the battery status is within the set range; When the battery state is within a set range, controlling the first DC / DC converter to have an on state; When the battery state is outside the set range, the first DC / DC converter is controlled to have a disconnected state.

14. The balancing control method for multiple battery modules according to claim 12, wherein: Controlling the first DC / DC converter to be in an on state or an off state comprises: determining whether the first DC / DC converter is in an on state; When the first DC / DC converter is in an on state, determining whether the battery state is less than a reference value by a first value; When the battery state is less than the reference value by a first value, converting the on state of the first DC / DC converter into an off state; When the battery state is not less than the reference value by a first value, the first DC / DC converter is kept in the on state.

15. The method according to claim 14, wherein: Controlling the first DC / DC converter to be in an on state or an off state comprises: determining whether the first DC / DC converter is in an on state; When the first DC / DC converter is in the disconnected state, determining whether the battery state is less than a reference value by a second value; When the battery state is less than the reference value by a second value, keeping the first DC / DC converter in a disconnected state; When the battery state is not less than the reference value by a second value, the off state of the first DC / DC converter is converted into the on state.

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