Battery control device and method

Abstract

A battery control device according to one embodiment of the present invention is a battery control device located in a battery system including a plurality of batteries, and may include at least one processor; and a memory configured to store at least one instruction executed through the at least one processor. At least one of the above instructions may include: an instruction to confirm the operating mode of the battery system; an instruction to set a reference voltage based on a reference voltage setting criterion defined in correspondence with the confirmed operating mode; an instruction to select one or more target batteries having a voltage within a preset range of the reference voltage; and an instruction to control the target batteries so that they are connected in parallel with each other.

Description

Technical Field

[0001] This application claims the benefit of the filing date of Korean Patent Application No. 10-2024-0054516, filed with the Korean Intellectual Property Office on April 24, 2024, and all of the content disclosed in the document of the Korean patent application is incorporated herein.

[0002] The present invention relates to a battery control device and a control method thereof, and more specifically, to a battery control device and a control method thereof for improving the power efficiency of a battery system.

Background Art

[0003] A secondary battery is a battery that can be reused through charging even after discharging, and can be used as an energy source for small devices such as mobile phones, tablet PCs, and vacuum cleaners, and can also be used as an energy source for medium and large devices such as automobiles and energy storage systems (ESSs) for smart grids.

[0004] Secondary batteries are applied to a system in the form of an assembly such as a battery module in which a number of battery cells are connected in series or parallel according to the requirements of the system, or a battery rack in which battery modules are connected in series or parallel. In the case of medium and large devices such as an ESS for a smart grid, a high-capacity battery system in which a number of battery racks are connected in parallel can be applied to satisfy the required capacity of the device.

[0005] Generally, in a battery system including batteries connected in parallel, when trying to switch the batteries from a parallel-disconnected state to a parallel-connected state, in order to prevent an inrush current from occurring, after selecting a battery showing a low voltage difference, the selected battery is connected to a DC link and connected in parallel with each other. Here, the battery connected to the DC link (online battery) executes a charge / discharge process according to the operation mode of the battery system, and the battery not connected to the DC link (Offline battery) waits in an idle mode state.

[0006] To improve the power efficiency of a battery system, it is necessary to maximize the number of online batteries participating in the charging and discharging process and minimize the number of offline batteries.

[0007] A related prior document is KR 10-2018-0009569 A. [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The objective of the present invention, which aims to solve the above-mentioned problems, is to provide a battery control device for improving the power efficiency of a battery system.

[0009] Another objective of the present invention, in order to solve the above-mentioned problems, is to provide a battery control method using such a battery control device. [Means for solving the problem]

[0010] A battery control device according to one embodiment of the present invention for achieving the above objective is a battery control device located in a battery system including a plurality of batteries, and may include at least one processor; and a memory configured to store at least one instruction executed through the at least one processor.

[0011] At least one of the above instructions may include: an instruction to confirm the operating mode of the battery system; an instruction to set a reference voltage based on a reference voltage setting criterion defined in correspondence with the confirmed operating mode; an instruction to select one or more target batteries having a voltage within a preset range of the reference voltage; and an instruction to control the target batteries so that they are connected in parallel with each other.

[0012] The above operating modes may include one or more of the following: charging mode, discharging mode, and mixed charge / discharge mode.

[0013] The command to check the operating mode of the battery system may include a command to determine the current operating mode of the battery system based on charge / discharge schedule information, which includes operating modes for different time intervals.

[0014] The instruction for setting the reference voltage may include an instruction to set the lowest voltage value among the battery voltages as the reference voltage when the battery system is operating in charging mode.

[0015] The instruction for setting the reference voltage may include an instruction to set the highest voltage value among the battery voltages as the reference voltage when the battery system is operating in discharge mode.

[0016] The instruction for setting the above reference voltage may include an instruction to set the voltage value of a specific battery among the above batteries as the reference voltage when the battery system is operating in a mixed charge / discharge mode.

[0017] The command for setting the reference voltage may include, for each battery, a command to determine the number of other batteries whose voltage difference from the voltage value of that battery is within a predetermined range; and a command to set the voltage value of the battery with the largest number of other batteries as the reference voltage.

[0018] The above at least one instruction may further include an instruction to connect in parallel with the target battery one or more batteries whose parallel connection has been disconnected during the charging or discharging process of the target battery, and whose voltage difference with the target battery falls within a predetermined range.

[0019] The command to control the above target batteries so that they are connected in parallel may include a command to send a switch control signal to the battery management device of each of the target batteries, causing the switch connecting the battery to the DC link to be switched to the closed state.

[0020] A battery control method according to one embodiment of the present invention for achieving the above-mentioned other objective is a battery control method by a battery control device located in a battery system including a plurality of batteries, and includes the steps of: confirming the operating mode of the battery system; setting a reference voltage based on a reference voltage setting criterion defined in correspondence with the confirmed operating mode; selecting one or more target batteries having a voltage within a preset range of the reference voltage; and controlling the target batteries so that they are connected in parallel with each other.

[0021] The above operating modes may include one or more of the following: charging mode, discharging mode, and mixed charge / discharge mode.

[0022] The step of checking the operating mode of the battery system described above may include determining the current operating mode of the battery system based on charge / discharge schedule information, which includes operating modes for different time intervals.

[0023] The step of setting the reference voltage described above may include setting the lowest voltage value among the battery voltage values ​​as the reference voltage when the battery system is operating in charging mode.

[0024] The step of setting the reference voltage described above may include setting the highest voltage value among the battery voltage values ​​as the reference voltage when the battery system is operating in discharge mode.

[0025] The step of setting the reference voltage described above may include setting the voltage value of a specific battery among the batteries as the reference voltage when the battery system is operating in a mixed charge-discharge mode.

[0026] The step of setting the reference voltage may include, for each battery, determining the number of other batteries whose voltage difference from the voltage value of each battery is within a predetermined range; and setting the voltage value of the battery with the largest number of other batteries as the reference voltage.

[0027] In the process of charging or discharging the target battery, the above battery control method may further include a step of connecting in parallel one or more batteries, among the one or more batteries whose parallel connection has been released, whose voltage difference from the target battery falls within a preset range, to the target battery.

[0028] The step of controlling the target batteries to be connected in parallel with each other may include a step of transmitting a switch control signal for switching the switch connecting the battery and the DC link to the closed state to each battery management device of the target batteries.

Advantages of the Invention

[0029] According to the embodiment of the present invention as described above, the number of batteries participating in the charge-discharge process can be maximized, and the power efficiency of the battery system can be improved.

Brief Description of the Drawings

[0030] [Figure 1] It is a block diagram of a general energy storage system. [Figure 2] It is a graph for explaining a general battery control method. [Figure 3] It is a block diagram of a battery system according to an embodiment of the present invention. [Figure 4] It is an operation flowchart of a battery control method according to an embodiment of the present invention. [Figure 5] It is an operation flowchart of a battery control method according to another embodiment of the present invention. [Figure 6] It is a reference table for explaining a reference voltage setting method in a charge-discharge mixed mode according to an embodiment of the present invention, and is an illustration of the voltage difference between batteries. [Figure 7] It is a graph for explaining an active balancing method in a charging mode according to an embodiment of the present invention. [Figure 8] It is a graph for explaining an active balancing control method in a discharging mode according to an embodiment of the present invention. [Figure 9] This graph illustrates an active balancing control method in a charge-discharge mixing mode according to an embodiment of the present invention. [Figure 10] This is a block diagram of a battery control device according to an embodiment of the present invention. [Modes for carrying out the invention]

[0031] The present invention can be modified in various ways and has many embodiments; therefore, specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this should be understood not as limiting the present invention to specific embodiments, but rather as including all modifications, equivalents, or substitutes that fall within the spirit and technical scope of the present invention. Similar reference numerals are used for similar components in the description of each drawing.

[0032] Terms such as First, Second, A, B, etc., may be used to describe various components, but the components should not be limited by such terms. The terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the First component may be named the Second component, and similarly, the Second component may be named the First component. The term "and / or" includes a combination of multiple related items or one of multiple related items.

[0033] When it is stated that one component is "combined" or "connected" to another component, it should be understood that this may mean that it is directly combined or connected to the other component, but that another component may exist in between. Conversely, when it is stated that one component is "directly combined" or "directly connected" to another component, it should be understood that there is no other component in between.

[0034] The terms used in this application are used solely to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless they are clearly different in context. In this application, terms such as “includes” or “having” are intended to specify the presence of features, figures, steps, actions, components, parts, or combinations thereof as described in the specification, and should not be understood to preemptively exclude the presence or possibility of adding one or more other features, figures, steps, actions, components, parts, or combinations thereof.

[0035] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as those generally understood by a person of ordinary skill in the art to which this invention pertains. Terms as defined in commonly used dictionaries should be interpreted as having the meaning consistent with their meaning in the context of the relevant art, and not as ideal or overly formal unless explicitly defined herein.

[0036] Some terms used in this specification are defined as follows:

[0037] A battery cell is a basic unit that stores electricity, while a battery module refers to an assembly of multiple battery cells that are electrically connected.

[0038] A battery rack refers to a single-structure system in which modules, as defined by the battery manufacturer, are electrically connected and can be monitored and controlled through a Battery Management System (BMS). It can consist of multiple battery modules (or battery packs) and one BPU or protective device.

[0039] A battery bank can refer to a collection of large-scale battery rack systems, each consisting of multiple battery racks connected in parallel. Monitoring and control of individual battery rack BMSs (RBMSs) can be performed through a battery bank-level BMS.

[0040] A battery assembly refers to a collection comprising multiple electrically connected battery cells that is applied to a specific system or device to function as a power source. Here, a battery assembly can mean a battery module, battery pack, battery rack, or battery bank, but the scope of the present invention is not limited to these individuals.

[0041] SOC (State of Charge) represents the current charge level of a battery as a percentage [%], while SOH (State of Health) represents the current state of a battery compared to its ideal or initial state as a percentage [%].

[0042] Figure 1 is a block diagram of a typical energy storage system.

[0043] The basic unit of a battery that stores electricity in an energy storage system (ESS) is usually a battery cell. A series or parallel combination of battery cells forms a battery module, and a large number of battery modules can constitute a battery rack. In other words, a battery rack is a series or parallel combination of battery modules and can be the basic unit of a battery system. Here, depending on the device or system in which the battery is used, a battery module may also be called a battery pack.

[0044] Referring to Figure 1, a single battery rack 10 can include multiple battery modules and one battery protection unit (BPU) or other protection devices. The battery rack can be monitored and controlled through an RBMS (Rack BMS). The RBMS can monitor the current, voltage, and temperature of each battery rack under its control, calculate the State of Charge (SOC) of the batteries based on the monitoring results, and control charging and discharging.

[0045] On the other hand, a Battery Protection Unit (BPU) is a device for protecting batteries from abnormal and fault currents on a rack-by-rack basis. A BPU can include a main contactor (MC), fuse, circuit breaker (CB), or disconnect switch (DS). Here, the main contactor can include a positive and negative main contactor. The BPU can control the battery system on a rack-by-rack basis by switching the main contactor on / off according to the RBMS control. The BPU can also protect the batteries from short-circuit currents using a fuse in the event of a short circuit. Thus, a typical battery system can be controlled through protective devices such as a BPU and switchgear.

[0046] On the other hand, each battery section, which is composed of numerous batteries and peripheral circuits and devices, is provided with a Battery System Controller (BSC) 20 that can monitor and control controlled objects such as voltage, current, temperature, and circuit breakers. The BSC is the highest-level control device for a battery system, including a bank-unit battery system that includes multiple battery racks, and can also be used as a control device in a battery system with multiple bank-level structures.

[0047] Furthermore, a Power Conversion System (PCS) 40, provided for each battery section, is a device that performs actual charging and discharging based on charge / discharge commands from the EMS 30. The Power Conversion System may consist of a power conversion unit (DC / AC inverter) and a controller. On the other hand, the output of each BPU can be connected to a power generation device (e.g., a solar power generation system) and the PCS 40 via a DC link (or DC bus), and the PCS 40 can be connected to the grid. In addition, an Energy Management System (EMS) 30 or Power Management System (PMS) manages the ESS system as a whole.

[0048] Figure 2 is a graph illustrating a typical battery control method.

[0049] In a battery system containing multiple battery racks, when attempting to switch the racks from a disconnected to a connected state, select racks with low voltage differences and connect them in parallel to prevent inrush current from occurring within the battery system.

[0050] For example, if the voltages of the five racks (Rack #1 to #5) are [755V, 800V, 803V, 799V, 801V] and the predefined voltage range is defined as 10V, then Rack #2, Rack #3, Rack #4, and Rack #5 can be connected in parallel to each other via a DC link. Here, Racks #2 to #5 perform the charge and discharge process according to the operating mode of the battery system, while Rack #1, which is not connected to the DC link, remains in idle mode.

[0051] Generally, offline battery racks connect to the DC link when their voltage equals that of the online battery racks. However, in the case of ESSs that work in conjunction with PV (photovoltaic) systems, the charge / discharge schedule of the battery system is determined according to the power generation status of the PV system. Therefore, the period during which the battery system operates in charge mode or discharge mode is limited, and the period during which the offline battery rack cannot be switched online may be longer.

[0052] For example, as shown in Figure 2, when the battery system operates in charging mode, the voltages of Racks #2 to #5 will increase for a certain period of time due to the PV power. As a result, Rack #1, which is in an offline state, will remain offline for a long period of time without being able to switch to an online state.

[0053] Such common battery control methods can lead to longer periods during which not all battery racks can participate in the charging and discharging process, potentially reducing the charging and discharging efficiency of the battery system.

[0054] Figure 3 is a block diagram of a battery system according to an embodiment of the present invention.

[0055] Referring to Figure 3, the battery system according to an embodiment of the present invention may include a plurality of batteries 100, a plurality of battery management devices 200 provided in correspondence with each of the plurality of batteries for managing and controlling the corresponding batteries, and a battery control device 300 that works in conjunction with the plurality of battery management devices 200.

[0056] Battery 100 can refer to a battery rack, but the scope of the present invention is not limited thereto. That is, battery 100 according to the present invention can refer to a battery module, a battery pack, or a battery bank.

[0057] The batteries 100 can be configured by connecting them in parallel. Here, each of the batteries 100 can be electrically connected to a DC link and connected in parallel with the other batteries.

[0058] Each of the batteries 100 may include a switch located at its input / output terminal, and when the switch is switched from the closed state to the open state, the electrical connection to the DC link is interrupted and the parallel connection with other batteries is released.

[0059] The battery management device 200 can manage and control the corresponding battery 100 by collecting status information about the battery and performing predefined control operations based on the collected status information. In this case, the battery management device 200 can control the charging and discharging of the battery and diagnose whether or not there is a fault in the battery cell based on the battery status information.

[0060] The battery management device 200 can control the operation of the switches provided at the input / output terminals of the battery 100.

[0061] Each of the battery management devices 200 is connected to the battery control device 300 via a network and can transmit battery status information to the battery control device 300 and receive control commands from the battery control device 300 to operate. Here, the battery management device 200 can receive switch control signals from the battery control device 300 to control the operation of the switches and can control the on / off operation of the switches according to the switch control signals.

[0062] The battery control device 300 can monitor and control the operating status of each of the battery management devices 200.

[0063] The battery control device 300 can be a BSC (Battery System Controller), an EMS (Energy Management System), or a PMS (Power Management System).

[0064] The battery control device 300 collects the status values ​​of each battery when the parallel connection of the batteries 100 is disconnected, and can select one or more target batteries to be connected in parallel based on the collected status values.

[0065] Subsequently, the battery control device 300 can control the target batteries so that they are connected in parallel to each other. Here, the battery control device 300 can send a switch control signal to each battery management device of the target batteries so that the switch is turned to the closed state, thereby connecting the target batteries to the DC link.

[0066] Figure 4 is an operation flowchart of a battery control method according to an embodiment of the present invention.

[0067] The battery control method according to an embodiment of the present invention can be performed by a battery control device located within a battery system including multiple batteries. Here, the battery control device can correspond to a higher-level control device that works in conjunction with each battery management device of the batteries, and can correspond to, for example, a BSC, EMS, or PMS that works in conjunction with multiple BMSs.

[0068] The battery control device can set a reference voltage based on the state value of each battery when the parallel connection of the batteries is disconnected (S410). Here, if an event occurs in which the batteries must be connected in parallel (for example, an event in which the battery system switches from idle mode to operating mode), the battery control device can set the reference voltage at the time the event occurs.

[0069] The battery control unit can receive one or more status values ​​for each battery from each battery management device (e.g., a BMS). Here, the battery status value may include one or more of the voltage value and State of Charge (SOC) value for each battery.

[0070] The battery control device can check the operating mode of the battery system and set a reference voltage based on a reference voltage setting criterion defined in correspondence with the operating mode.

[0071] The operating mode may include one or more of the following: charging mode, discharging mode, and mixed charge / discharge mode. Here, the battery control device can determine whether the current battery system is operating in one of the following modes: charging mode, discharging mode, or mixed charge / discharge mode.

[0072] A battery control unit can receive information about the operating mode from a higher-level control unit and determine the current operating mode of the battery system based on the received information. For example, if the battery control unit is a BSC (Battery System Control Unit), it can receive information about the operating mode from its higher-level control unit, such as an EMS (Electronic System Management Unit) or PMS (Power Management System).

[0073] The battery control unit can determine the current operating mode of the battery system based on charge / discharge schedule information, which includes operating modes for different time intervals. The battery control unit can receive charge / discharge schedule information from a higher-level control unit.

[0074] For example, the charge / discharge schedule information can include data that defines the operating mode for each time interval, such as [00:00~11:00; discharge mode], [11:00~15:00; charge mode], [15:00~17:00; mixed charge / discharge mode], and [17:00~24:00; discharge mode]. The battery control unit can receive the charge / discharge schedule information from the higher-level control unit and store it in its memory. If a parallel connection event occurs at a specific point in time, the battery control unit can use the charge / discharge schedule information to determine the operating mode corresponding to that point in time.

[0075] The reference voltage setting criteria for each operating mode can be defined differently from one another.

[0076] In charging mode, the lowest voltage value among the battery's voltage values ​​is set as the reference voltage, and in discharging mode, the highest voltage value among the battery's voltage values ​​can be set as the reference voltage.

[0077] In charge-discharge mixed mode, the voltage value of a specific battery can be set as the reference voltage. Here, the battery with the voltage value used as the reference voltage can be the battery that has the largest number of other batteries that can be connected in parallel.

[0078] The battery control device can select one or more target batteries from among the batteries that have a voltage within a preset range from the reference voltage set in S410 (S420).

[0079] For example, if the voltage values ​​of the batteries (Bat #1 to Bat #5) are [755V, 805V, 810V, 795V, 765V] and the current operating mode of the battery system is charging mode, the reference voltage value can be set to 755V. Here, if the predefined voltage range for selecting the target battery is 10V, the battery control unit can determine Bat #1 and Bat #5 as the target batteries.

[0080] As another example, if the voltage values ​​of the batteries (Bat #1 to Bat #5) are [755V, 805V, 810V, 795V, 765V], and the current operating mode of the battery system is discharge mode, the reference voltage value can be set to 810V. Here, if the predefined voltage range for target battery selection is 10V, the battery control unit can determine Bat #2 and Bat #3 as target batteries.

[0081] The battery control device can control the target batteries selected in S420 to be connected in parallel with each other (S430).

[0082] Specifically, the battery control device can control each of the target batteries so that it is connected to a DC link. Here, the battery control device can control the target batteries so that they are connected in parallel with each other by sending a switch control signal to the battery management device of each target battery, which causes the switch connecting the battery to the DC link to be switched to the closed state.

[0083] Figure 5 is an operation flowchart of a battery control method according to another embodiment of the present invention.

[0084] When a parallel connection event occurs, the battery control unit can determine the current operating mode of the battery system (S510). Here, the battery control unit can determine whether the current battery system is operating in charging mode, discharging mode, or a mixed charge / discharge mode.

[0085] The battery control unit can either confirm the current operating mode through a higher-level control unit, or determine the current operating mode using charge / discharge schedule information and the current time received from the higher-level control unit.

[0086] The battery control unit can set the reference voltage based on the operating mode confirmed in S510.

[0087] If the current operating mode of the battery system is charging mode (Y in S521), the battery control device can set the lowest voltage value (Vmin) among the battery voltage values ​​as the reference voltage (Vref) (S531). For example, if the voltage values ​​of the batteries (Bat #1 to Bat #5) are [755V, 805V, 810V, 795V, 765V], the reference voltage value can be set to 755V.

[0088] If the current operating mode of the battery system is discharge mode (Y in S522), the battery control device can set the highest voltage value (Vmax) among the battery voltage values ​​as the reference voltage (Vref) (S532). For example, if the voltage values ​​of the batteries (Bat #1 to Bat #5) are [755V, 805V, 810V, 795V, 765V], the reference voltage value can be set to 810V.

[0089] If the current operating mode of the battery system is a mixed charge-discharge mode (Y in S523), the battery control device can select a specific battery from among the batteries as the reference battery (Bat_ref) and set the voltage value of the reference battery (Vbat_ref) as the reference voltage (Vref) (S533). Here, the battery control device can determine the battery with the largest number of other batteries that can be connected in parallel as the reference battery (Bat_ref).

[0090] The following describes in detail, with reference to Figure 6, the method for setting the reference voltage in the charge-discharge mixed mode according to an embodiment of the present invention.

[0091] Figure 6 is a reference table illustrating a method for setting a reference voltage in a charge-discharge mixed mode according to an embodiment of the present invention, and shows an example of the voltage difference between batteries.

[0092] The battery control device can calculate the difference in state values ​​for each battery compared to the other batteries. For example, if the voltage values ​​of batteries (Bat #1 to Bat #5) are [755V, 805V, 803V, 810V, and 765V], the battery control device can calculate the voltage difference for each battery (Bat #1 to Bat #5) compared to the other batteries, as shown in Figure 6.

[0093] Subsequently, the battery control device can determine the number of other batteries that can be connected in parallel with each battery. Here, the battery control device can determine the number of other batteries that can be connected in parallel with each battery by determining the number of other batteries whose voltage value is within a predetermined range that is different from the state value of each battery.

[0094] Subsequently, the battery control device can define the battery with the largest number of other batteries that can be connected in parallel as the reference battery.

[0095] For example, if the voltage difference between batteries (Bat #1 to Bat #5) is calculated as shown in Figure 6, and the predefined voltage range for selecting the reference battery is ±5V, then the number of batteries that can be connected in parallel for each of the batteries (Bat #1 to Bat #5) can be determined to be 0, 2, 1, 1, and 0. In this case, the battery control device can determine Bat #2, which has the largest number of batteries that can be connected in parallel, as the reference battery, and set the voltage value of Bat #2, 805V, as the reference voltage (Vref).

[0096] Referring again to Figure 5, the battery control device can select one or more target batteries having a reference voltage and a voltage within a preset range in S531 to S533 (S540).

[0097] For example, if the voltage values ​​of the batteries (Bat #1 to Bat #5) are [755V, 805V, 810V, 795V, 765V] and the current operating mode of the battery system is charging mode, the reference voltage value can be set to 755V (S531). Here, if the predefined voltage range for selecting the target battery is 10V, the battery control unit can determine Bat #1 and Bat #5 as the target batteries.

[0098] As another example, if the voltage values ​​of the batteries (Bat #1 to Bat #5) are [755V, 805V, 810V, 795V, 765V] and the current operating mode of the battery system is discharge mode, the reference voltage value can be set to 810V (S532). Here, if the predefined voltage range for target battery selection is 10V, the battery control unit can determine Bat #2 and Bat #3 as target batteries.

[0099] In another example, if the voltage values ​​of the batteries (Bat #1 to Bat #5) are [755V, 805V, 803V, 810V, 765V] and the current operating mode of the battery system is a mixed charge-discharge mode, the reference voltage value can be set to 805V (S533). Here, if the predefined voltage range for selecting the target battery is ±5V, the battery control unit can determine Bat #2, Bat #3, and Bat #4 as the target batteries.

[0100] The battery control device can control the target batteries selected in S540 to be connected in parallel with each other (S550).

[0101] Specifically, the battery control device can control each of the target batteries so that it is connected to a DC link. Here, the battery control device can control the target batteries so that they are connected in parallel with each other by sending a switch control signal to the battery management device of each target battery, which causes the switch connecting the battery to the DC link to be switched to the closed state.

[0102] Subsequently, the battery system can operate according to the current operating mode with the target battery connected to the DC link.

[0103] The battery control device can perform active balancing control during the operation of the battery system based on the voltage difference between the target battery (online battery) and the remaining batteries (offline battery) (S560).

[0104] Specifically, the battery control device can monitor the voltage difference between the target battery and the offline batteries during the charging or discharging process of the target battery according to its operating mode. Here, the battery control device can connect the offline batteries whose voltage difference with the target battery falls within a preset range to the DC link and connect them in parallel with the target battery.

[0105] The following describes the active balancing methods according to the operating mode of an embodiment of the present invention, with reference to Figures 7 to 9.

[0106] Figure 7 is a graph illustrating the active balancing method in charging mode according to an embodiment of the present invention.

[0107] If the voltage values ​​of the batteries (Bat #1 to Bat #5) are [755V, 805V, 810V, 795V, 765V], the reference voltage value can be set to 755V. Here, if the predefined voltage range for selecting the target batteries is 10V, the target batteries are determined to be Bat #1 and Bat #5, and Bat #1 and Bat #5 are connected to the DC link.

[0108] As the battery system operates in charging mode, the voltages of Bat #1 and Bat #5 gradually increase from the average voltage of 760V.

[0109] The battery control unit can monitor the average voltage of the online batteries (Bats #1 and #5) and the voltage difference between each of the offline batteries (Bats #2, #3, and #4). The battery control unit can then connect any of the offline batteries (Bats #2, #3, and #4) whose voltage difference with the online batteries (Bats #1 and #5) falls within a preset range to the DC link and switch them online.

[0110] If the predefined voltage range for switching an offline battery online is ±1V, the battery control unit can connect Bat #4 to the DC link at time t1 to switch it online. Then, at time t2, the battery control unit can connect Bat #2 to the DC link to switch it online. Then, at time t3, the battery control unit can connect Bat #3 to the DC link to switch it online.

[0111] In charging mode, the lowest voltage value among the battery voltages is set as the reference voltage, allowing batteries with lower voltage ranges to participate in the charging process at the start of the battery system's operation. Subsequently, as charging progresses, the remaining batteries join the charging process sequentially, until eventually all batteries are able to participate in the charging process.

[0112] Figure 8 is a graph illustrating the active balancing control method in discharge mode according to an embodiment of the present invention.

[0113] If the voltage values ​​of the batteries (Bat #1 to Bat #5) are [755V, 805V, 810V, 795V, 765V], the reference voltage value can be set to 810V. Here, if the predefined voltage range for selecting the target battery is 10V, the target batteries are determined to be Bat #2 and Bat #3, and Bat #2 and Bat #3 are connected to the DC link.

[0114] As the battery system operates in discharge mode, the voltages of Bat #2 and Bat #3 gradually decrease from the average voltage of 807.5V.

[0115] The battery control unit can monitor the average voltage of the online batteries (Bats #2 and #3) and the voltage difference between each of the offline batteries (Bats #1, #4, and #5). The battery control unit can then connect any of the offline batteries (Bats #1, #4, and #5) whose voltage difference with the online batteries (Bats #2 and #3) falls within a preset range to the DC link and switch them online.

[0116] If the predefined voltage range for switching an offline battery online is ±1V, the battery control unit can connect Bat #4 to the DC link at time t1 to switch it online. Then, at time t2, the battery control unit can connect Bat #5 to the DC link to switch it online. Then, at time t3, the battery control unit can connect Bat #1 to the DC link to switch it online.

[0117] In discharge mode, the highest voltage value among the battery voltages is set as the reference voltage, allowing batteries with a high voltage range to participate in the discharge process at the start of the battery system's operation. Subsequently, as the discharge progresses, the remaining batteries join the discharge process sequentially, until eventually all batteries are able to participate in the discharge process.

[0118] Figure 9 is a graph illustrating the active balancing control method in charge-discharge mixed mode according to an embodiment of the present invention.

[0119] If the voltage values ​​of the batteries (Bat #1 to Bat #5) are [755V, 805V, 803V, 810V, 765V], the reference voltage value can be set to 805V. Here, if the predefined voltage range for selecting the target battery is ±5V, the target batteries are determined to be Bat #2, Bat #3, and Bat #4, and Bat #2, Bat #3, and Bat #4 are connected to the DC link.

[0120] As the battery system operates in a mixed charge-discharge mode, the voltages of Bat #2, Bat #3, and Bat #4 can increase or decrease from the average voltage of 806V.

[0121] The battery control unit can monitor the average voltage of the online batteries (Bats #2, #3, #4) and the voltage difference between each of the offline batteries (Bats #1, #5). The battery control unit can then connect any of the offline batteries (Bats #1, #5) whose voltage difference with the online batteries (Bats #2, #3, #4) falls within a preset range to the DC link and switch them online.

[0122] If the predefined voltage range for switching an offline battery online is ±1V, the battery control unit can connect Bat #5 to the DC link at time t1 to switch it online. Subsequently, at time t2, the battery control unit can connect Bat #1 to the DC link to switch it online.

[0123] In mixed charge / discharge mode, the voltage of the battery with the largest number of other batteries that can be connected in parallel is set as the reference voltage. This allows as many batteries as possible to participate in the charging process at the start of the battery system's operation, provided that no inrush current occurs. Subsequently, as charging or discharging progresses, the remaining batteries sequentially participate in the charge / discharge process, allowing the maximum number of batteries to participate in the charge / discharge process.

[0124] Figure 10 is a block diagram of a battery control device according to an embodiment of the present invention.

[0125] The battery control device 1000 according to an embodiment of the present invention is located within a battery system and can be linked to each battery management device of the battery. For example, the battery control device 1000 may correspond to or be implemented as part of a BSC, EMS, or PMS, or as being included in any one of these.

[0126] The battery control device 1000 may include at least one processor 1010, a memory 1020 that stores at least one instruction executed through the processor, and a transceiver 1030 that is connected to a network and performs communication.

[0127] At least one of the above instructions may include: an instruction to confirm the operating mode of the battery system; an instruction to set a reference voltage based on a reference voltage setting criterion defined in correspondence with the confirmed operating mode; an instruction to select one or more target batteries having a voltage within a preset range of the reference voltage; and an instruction to control the target batteries so that they are connected in parallel with each other.

[0128] The above operating modes may include one or more of the following: charging mode, discharging mode, and mixed charge / discharge mode.

[0129] The command to check the operating mode of the battery system may include a command to determine the current operating mode of the battery system based on charge / discharge schedule information, which includes operating modes for different time intervals.

[0130] The instruction for setting the reference voltage may include an instruction to set the lowest voltage value among the battery voltages as the reference voltage when the battery system is operating in charging mode.

[0131] The instruction for setting the reference voltage may include an instruction to set the highest voltage value among the battery voltages as the reference voltage when the battery system is operating in discharge mode.

[0132] The instruction for setting the above reference voltage may include an instruction to set the voltage value of a specific battery among the above batteries as the reference voltage when the battery system is operating in a mixed charge / discharge mode.

[0133] The command for setting the reference voltage may include, for each battery, a command to determine the number of other batteries whose voltage difference from the voltage value of that battery is within a predetermined range; and a command to set the voltage value of the battery with the largest number of other batteries as the reference voltage.

[0134] The above at least one instruction may further include an instruction to connect in parallel with the target battery one or more batteries whose parallel connection has been disconnected during the charging or discharging process of the target battery, and whose voltage difference with the target battery falls within a predetermined range.

[0135] The command to control the above target batteries so that they are connected in parallel may include a command to send a switch control signal to the battery management device of each of the target batteries, causing the switch connecting the battery to the DC link to be switched to the closed state.

[0136] The battery control device 1000 may further include an input interface device 1040, an output interface device 1050, a storage device 1060, and the like. Each component included in the battery control device 1000 can communicate with one another via a bus 1070.

[0137] Here, processor 1010 can mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which the method according to the embodiment of the present invention is performed. Memory (or storage device) can consist of at least one of a volatile storage medium and a non-volatile storage medium. For example, memory can consist of at least one of a read-only memory (ROM) and a random access memory (RAM).

[0138] The operation of the method according to an embodiment of the present invention can be embodied as a computer-readable program or code on a computer-readable recording medium. A computer-readable recording medium includes all types of recording devices that store data that can be read by a computer system. Furthermore, computer-readable recording media can be distributed across networked computer systems, allowing computer-readable programs or code to be stored and executed in a distributed manner.

[0139] Some aspects of the present invention have been described in the context of apparatus, but they can also be described by corresponding methods, where a block or apparatus corresponds to a method step or a feature of a method step. Similarly, aspects described in the context of a method can be described by corresponding blocks or items or features of corresponding apparatus. Some or all of the method steps can be carried out by (or using) hardware devices such as, for example, a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, one or more of the most important method steps can be carried out by such devices.

[0140] While preferred embodiments of the present invention have been described above with reference to the present invention, those skilled in the art will understand that the present invention can be modified and altered in various ways without departing from the spirit and scope of the invention as set forth in the following claims. [Explanation of symbols]

[0141] 100:Battery 200:Battery management device 300, 1000: Battery control device

Claims

1. A battery control device located within a battery system containing multiple batteries, At least one processor; and Includes memory configured to store at least one instruction executed through the at least one processor, The at least one instruction is, A command to confirm the operating mode of the aforementioned battery system; An instruction to set the reference voltage based on the reference voltage setting criteria defined in correspondence with the confirmed operating mode; A command to select one or more target batteries having a voltage within a preset range of the aforementioned reference voltage; and A battery control device that includes commands for controlling the target batteries to be connected in parallel with one another.

2. The aforementioned operating mode is The battery control device according to claim 1, comprising one or more of a charging mode, a discharging mode, and a charge-discharge mixed mode.

3. The command to confirm the operating mode of the aforementioned battery system is: The battery control device according to claim 2, comprising a command to determine the current operating mode of the battery system based on charge / discharge schedule information including operating modes for different time intervals.

4. The command to set the aforementioned reference voltage is: The battery control device according to claim 1, which includes a command to set the lowest voltage value among the voltage values ​​of the battery as the reference voltage when the battery system is operating in charging mode.

5. The command to set the aforementioned reference voltage is: The battery control device according to claim 1, which includes a command to set the highest voltage value among the voltage values ​​of the battery as the reference voltage when the battery system is operating in discharge mode.

6. The command to set the aforementioned reference voltage is: The battery control device according to claim 1, which includes a command to set the voltage value of a specific battery among the batteries as a reference voltage when the battery system is operating in a charge-discharge mixed mode.

7. The command to set the aforementioned reference voltage is: A command to determine, for each battery, the number of other batteries whose voltage difference from the voltage of that battery is within a predetermined range; and The battery control device according to claim 6, which includes a command to set the voltage value of the battery with the largest number of other batteries as the reference voltage.

8. The at least one instruction is, The battery control device according to claim 1, further comprising a command to connect in parallel with the target battery one or more batteries whose parallel connection has been disconnected during the charging or discharging process of the target battery, the batteries whose voltage difference with the target battery falls within a preset range.

9. The command to control the target batteries so that they are connected in parallel is: The battery control device according to claim 1, comprising a command to transmit a switch control signal to each battery management device of the target battery, which causes the switch connecting the battery and the DC link to be switched to the closed state.

10. A battery control method using a battery control device located within a battery system containing multiple batteries, A step to confirm the operating mode of the battery system; A step of setting the reference voltage based on the reference voltage setting criteria defined in correspondence with the confirmed operating mode; The steps of selecting one or more target batteries having a voltage within a preset range of the aforementioned reference voltage; and A battery control method comprising the step of controlling the target batteries so that they are connected in parallel with one another.

11. The aforementioned operating mode is The battery control method according to claim 10, comprising one or more of a charging mode, a discharging mode, and a charge-discharge mixed mode.

12. The step of confirming the operating mode of the battery system is: The battery control method according to claim 11, comprising the step of determining the current operating mode of the battery system based on charge / discharge schedule information including operating modes for different time intervals.

13. The step of setting the reference voltage is: The battery control method according to claim 10, further comprising the step of setting the lowest voltage value among the battery voltage values ​​as the reference voltage when the battery system is operating in charging mode.

14. The step of setting the reference voltage is: The battery control method according to claim 10, further comprising the step of setting the highest voltage value among the battery voltage values ​​as the reference voltage when the battery system is operating in discharge mode.

15. The step of setting the reference voltage is: The battery control method according to claim 10, further comprising the step of setting the voltage value of a specific battery among the batteries as a reference voltage when the battery system is operating in a charge-discharge mixed mode.

16. The step of setting the reference voltage is: For each battery, the step of determining the number of other batteries whose voltage difference from the voltage of the battery is within a predetermined range; and The battery control method according to claim 15, further comprising the step of setting the voltage value of the battery with the largest number of other batteries as the reference voltage.

17. The battery control method according to claim 10, further comprising the step of connecting one or more batteries, whose parallel connection has been disconnected during the charging or discharging process of the target battery, in parallel with the target battery, one or more batteries whose voltage difference with the target battery falls within a preset range.

18. The step of controlling the target batteries so that they are connected in parallel is: The battery control method according to claim 10, further comprising the step of transmitting a switch control signal to each battery management device of the target battery, which causes a switch connecting the battery and the DC link to be switched to the closed state.

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