Battery control device and method

Abstract

A battery control device according to an embodiment of the present invention is located in a battery system including a plurality of batteries, and may comprise: at least one processor; and a memory that stores at least one command that is executed through the at least one processor. The at least one command may include: a command for checking an operation mode of the battery system; a command for setting a reference voltage on the basis of a reference voltage setting criterion defined to correspond to the checked operation mode; a command for selecting target batteries having a voltage within a preset range of the reference voltage; and a command for controlling so that the target batteries are connected in parallel to each other.

Description

Battery control device and method

[0001] This application claims the benefit of Korean Patent Application No. 10-2024-0054516 filed with the Korean Intellectual Property Office on April 24, 2024, the entire disclosure of which is incorporated herein by reference.

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

[0003] Secondary batteries are batteries that can be reused by charging even after discharge, and can be used as an energy source for small devices such as mobile phones, tablet PCs, and vacuum cleaners, and are also used as an energy source for medium and large devices such as automobiles and ESS (Energy Storage Systems) for smart grids.

[0004] Secondary batteries are applied to systems in the form of assemblies, such as battery modules, in which multiple battery cells are connected in series and parallel, or battery racks, in which battery modules are connected in series and parallel, depending on the system requirements. For medium- to large-sized devices, such as ESS for smart grids, high-capacity battery systems, in which multiple battery racks are connected in parallel, can be applied to meet the device's capacity requirements.

[0005] Typically, a battery system including parallel-connected batteries selects batteries exhibiting a low voltage difference to prevent inrush current when switching from a parallel disconnected state to a parallel connected state, and then connects the selected batteries to a DC link to connect them in parallel. Here, batteries connected to the DC link (online batteries) perform a charge / discharge process according to the operating mode of the battery system, while batteries not connected to the DC link (offline batteries) wait in an idle mode.

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

[0007] Related prior literature includes KR 10-2018-0009569 A.

[0008] An object of the present invention to solve the above problems is to provide a battery control device for improving the power efficiency of a battery system.

[0009] Another object of the present invention to solve the above problems is to provide a battery control method using such a battery control device.

[0010] According to one embodiment of the present invention to achieve the above object, a battery control device is provided, which is located in a battery system including a plurality of batteries, and may include at least one processor; and a memory storing at least one command executed through the at least one processor.

[0011] The at least one command may include: a command for checking the operation mode of the battery system; a command for setting a reference voltage based on a reference voltage setting criterion defined in correspondence with the checked operation mode; a command for selecting target batteries having a voltage within a preset range from the reference voltage; and a command for controlling the target batteries to be connected in parallel with each other.

[0012] The above operation mode may include one or more of a charge mode, a discharge mode, and a charge-discharge mixed mode.

[0013] The command for checking the operation mode of the above battery system may include a command for determining the current operation mode of the battery system based on charge / discharge schedule information including the operation mode by time interval.

[0014] The command for setting the reference voltage may include a command for setting the lowest voltage value among the voltage values ​​of the batteries as the reference voltage when the battery system is operating in a charging mode.

[0015] The command for setting the reference voltage may include a command for setting the highest voltage value among the voltage values ​​of the batteries as the reference voltage when the battery system operates in discharge mode.

[0016] The command for setting the reference voltage may include a command for setting the voltage value of a specific battery among the batteries as the reference voltage when the battery system operates in a charge / discharge mixed mode.

[0017] The command for setting the reference voltage may include, for each battery, a command for determining the number of other batteries whose voltage values ​​differ from its own voltage value within a preset range; and a command for setting the voltage value of the battery with the largest number of other batteries as the reference voltage.

[0018] The at least one command may further include a command to connect, in parallel with the target batteries, one or more batteries from which the parallel connection is disconnected, the voltage difference with respect to the target batteries falling within a preset range, during the process of charging or discharging the target batteries.

[0019] The command for controlling the target batteries to be connected in parallel with each other may include a command for transmitting a switch control signal to the battery management device of each of the target batteries so that a switch connecting the battery and the DC link is turned into a closed state.

[0020]

[0021] According to one embodiment of the present invention for achieving the above other object, a battery control method is provided, which is a battery control method by a battery control device located in a battery system including a plurality of batteries, comprising: a step of identifying an operation mode of the battery system; a step of setting a reference voltage based on a reference voltage setting criterion defined in correspondence with the identified operation mode; a step of selecting target batteries having a voltage within a preset range and the reference voltage; and a step of controlling the target batteries to be connected in parallel with each other.

[0022] The above operation mode may include one or more of a charge mode, a discharge mode, and a charge-discharge mixed mode.

[0023] The step of checking the operation mode of the above battery system may include a step of determining the current operation mode of the battery system based on charge / discharge schedule information including the operation mode by time interval.

[0024] The step of setting the reference voltage may include a command for setting the lowest voltage value among the voltage values ​​of the batteries as the reference voltage when the battery system is operating in a charging mode.

[0025] The step of setting the reference voltage may include a step of setting the highest voltage value among the voltage values ​​of the batteries as the reference voltage when the battery system operates in discharge mode.

[0026] The step of setting the reference voltage may include a step of setting the voltage value of a specific battery among the batteries as the reference voltage when the battery system operates in a charge / discharge mixed mode.

[0027] The step of setting the reference voltage may include, for each battery, determining the number of other batteries whose voltage values ​​differ from its own voltage value within a preset range; and setting the voltage value of the battery with the largest number of other batteries as the reference voltage.

[0028] The above battery control method may further include a step of connecting, in parallel with the target batteries, one or more batteries from which the parallel connection is disconnected, the voltage difference with respect to the target batteries falling within a preset range, during the process of charging or discharging the target batteries.

[0029] The step of controlling the target batteries to be connected in parallel with each other may include the step of transmitting a switch control signal to a battery management device of each of the target batteries so that a switch connecting the battery and the DC link is switched to a closed state.

[0030] According to the above-described embodiment of the present invention, the power efficiency of the battery system can be improved by maximizing the number of batteries participating in the charging and discharging process.

[0031] Figure 1 is a block diagram of a typical energy storage system.

[0032] Figure 2 is a graph for explaining a general battery control method.

[0033] Figure 3 is a block diagram of a battery system according to an embodiment of the present invention.

[0034] Figure 4 is an operation flowchart of a battery control method according to an embodiment of the present invention.

[0035] Figure 5 is an operational flowchart of a battery control method according to another embodiment of the present invention.

[0036] FIG. 6 is a reference table for explaining a method for setting a reference voltage in a charge / discharge mixed mode according to an embodiment of the present invention, and is an example of a voltage difference between batteries.

[0037] FIG. 7 is a graph for explaining an active balancing method in a charging mode according to an embodiment of the present invention.

[0038] FIG. 8 is a graph for explaining an active balancing control method in discharge mode according to an embodiment of the present invention.

[0039] FIG. 9 is a graph for explaining an active balancing control method in a charge / discharge mixed mode according to an embodiment of the present invention.

[0040] Figure 10 is a block diagram of a battery control device according to an embodiment of the present invention.

[0041] 100: Battery

[0042] 200: Battery management device

[0043] 300, 1000: Battery control unit

[0044] The present invention is susceptible to various modifications and embodiments. Specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention. Throughout the description of each drawing, similar reference numerals have been used to designate similar components.

[0045] Terms such as "first," "second," "A," and "B" may be used to describe various components, but these components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, the first component could be referred to as the "second component," and similarly, the second component could also be referred to as the "first component." The term "and / or" includes any combination of multiple related items listed or any one of multiple related items listed.

[0046] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0047] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprise" or "have" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0048] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0049]

[0050] Some terms used in this specification are defined as follows:

[0051] A battery cell is the smallest unit that stores electricity, and a battery module is a collection of multiple battery cells that are electrically connected.

[0052] A battery rack is a single-structure system that electrically connects module units set by a battery manufacturer and can be monitored and controlled through a BMS (Battery Management System). It can be configured to include multiple battery modules (or battery packs) and one BPU or protection device.

[0053] A battery bank can refer to a large-scale battery rack system comprised of multiple battery racks connected in parallel. A battery bank-level BMS can monitor and control the rack BMS (RBMS) at the battery rack level.

[0054] A battery assembly is a collection of multiple electrically connected battery cells that function as a power source when applied to a specific system or device. Here, the battery assembly may refer to a battery module, battery pack, battery rack, or battery bank, but the scope of the present invention is not limited to these entities.

[0055] SOC (State of Charge) is the current charged state of the battery expressed as a percentage [%], and SOH (State of Health) is the current remaining state of the battery expressed as a percentage [%].

[0056]

[0057] Figure 1 is a block diagram of a typical energy storage system.

[0058] In an energy storage system (ESS), the smallest unit of a battery that stores power is typically a battery cell. A series / parallel combination of battery cells forms a battery module, and multiple battery modules can form a battery rack. In other words, a battery rack, consisting of a series / parallel combination of battery modules, can be the smallest unit of a battery system. Depending on the device or system in which the battery is used, a battery module may also be referred to as a battery pack.

[0059] Referring to Fig. 1, a single battery rack (10) may include multiple battery modules and a single BPU or protection device. The battery rack can be monitored and controlled through a Rack Battery Management System (RBMS). The RBMS monitors the current, voltage, and temperature of each battery rack it manages, and based on the monitoring results, calculates the battery's State of Charge (SOC) and controls charging and discharging.

[0060] Meanwhile, the Battery Protection Unit (BPU) is a device that protects batteries from abnormal current and fault current at the rack level. The BPU may include a main contactor (MC), a fuse, a circuit breaker (CB), or a disconnect switch (DS). The main contactor may include a positive main contactor and a negative main contactor. The BPU can control the battery system at the rack level by turning the main contactor on and off under the control of the RBMS. The BPU can also protect the battery from short-circuit current using a fuse in the event of a short-circuit. In this way, a typical battery system can be controlled through protective devices such as the BPU and switch gear.

[0061] Meanwhile, each battery section, which is composed of a plurality of batteries and peripheral circuits, devices, etc., is equipped with a BSC (Battery System Controller) (20) to monitor and control control targets such as voltage, current, temperature, circuit breakers, etc. The BSC is the top-level control device of a battery system including a bank-level battery system including a plurality of battery racks, and is also used as a control device in a battery system having a multiple bank-level structure.

[0062] In addition, the power conversion system (PCS) (40) installed in each battery section is a device that performs actual charging / discharging based on the charging / discharging command from the EMS (30), and may be configured to include a power conversion unit (DC / AC inverter) and a controller. Meanwhile, the output of each BPU may be connected to a power generation device (e.g., a solar power generation device) and the PCS (40) via a DC link (or DC bus), and the PCS (40) may be connected to the grid. In addition, the EMS (Energy Management System) (30) or PMS (Power Management System) manages the ESS system as a whole.

[0063]

[0064] Figure 2 is a graph for explaining a general battery control method.

[0065] A battery system including multiple battery racks selects racks having a low voltage difference and connects them in parallel with each other to prevent inrush current from occurring within the battery system when the racks are to be switched from a state of parallel disconnection to a state of parallel connection.

[0066] For example, if the voltages of each of the five racks (Rack #1 to #5) are [755 V, 800 V, 803 V, 799 V, 801 V] and the predefined voltage range is defined as 10 V, Rack #2, Rack #2, Rack #3, Rack #4, and Rack #5 can be connected to the DC link and connected in parallel with each other. Here, Rack #2 to #5 perform a charge / discharge process according to the operation mode of the battery system, and Rack #1, which is not connected to the DC link, waits in an idle mode.

[0067] Typically, an offline battery rack is connected to the DC link when the voltage of the online battery rack becomes the same. However, in the case of an ESS linked to a PV (Photovoltaic; solar power generation) system, the battery system's charge / discharge schedule is determined based on the PV system's power generation status. Therefore, the period during which the battery system operates in charge or discharge mode is limited, and the period during which the offline battery rack cannot be switched to the online state may be extended.

[0068] For example, as illustrated in Fig. 2, when the battery system operates in charging mode, the voltages of Racks #2 to #5 increase for a certain period of time due to PV power. Accordingly, Rack #1, which is in an offline state, cannot be switched online for a long period of time and remains in an offline state.

[0069] According to this general battery control method, the charge / discharge efficiency of the battery system may be reduced because the period during which not all battery racks participate in the charge / discharge process becomes longer.

[0070]

[0071] Figure 3 is a block diagram of a battery system according to an embodiment of the present invention.

[0072] Referring to FIG. 3, a battery system according to an embodiment of the present invention may include a plurality of batteries (100), a plurality of battery management devices (200) that are provided corresponding to each of the plurality of batteries and manage and control the corresponding batteries, and a battery control device (300) that is linked to the plurality of battery management devices (200).

[0073] The battery (100) may refer to a battery rack, but the scope of the present invention is not limited thereto. That is, the battery (100) according to the present invention may correspond to a battery module, a battery pack, or a battery bank.

[0074] The batteries (100) may be configured to be connected in parallel with each other. Here, each of the batteries (100) may be electrically connected to a DC link and connected in parallel with another battery.

[0075] Each of the batteries (100) may include a switch arranged at the input / output terminal, and when the switch is switched from a closed state to an open state, the electrical connection with the DC link is cut off, thereby releasing the parallel connection with other batteries.

[0076] The battery management device (200) can collect status information about the corresponding battery (100) and perform a predefined control operation based on the collected status information to manage and control the corresponding battery (100). Here, the battery management device (200) can control the charging and discharging of the battery and diagnose whether the battery cells are faulty based on the status information of the battery.

[0077] The battery management device (200) can control the operation of a switch provided at the input / output terminal of the battery (100).

[0078] Each of the battery management devices (200) is connected to the battery control device (300) via a network, transmits battery status information to the battery control device (300), and receives control commands from the battery control device (300) to operate. Here, the battery management device (200) receives a switch control signal for controlling the operation of the switch from the battery control device (300), and controls the on / off operation of the switch according to the switch control signal.

[0079] The battery control device (300) can monitor and control the operating status of each of the battery management devices (200).

[0080] The battery control device (300) may correspond to a BSC (Battery System Controller), an EMS (Energy Management System), or a PMS (Power Management System).

[0081] The battery control device (300) can collect the status values ​​of each battery while the parallel connection of the batteries (100) is disconnected, and select target batteries to be connected in parallel based on the collected status values.

[0082] Thereafter, the battery control device (300) can control the target batteries to be connected in parallel with each other. Here, the battery control device (300) can transmit a switch control signal to the battery management device of each of the target batteries to cause the switch to be switched to a closed state, thereby allowing the target batteries to be connected to the DC link.

[0083]

[0084] Figure 4 is an operation flowchart of a battery control method according to an embodiment of the present invention.

[0085] A battery control method according to an embodiment of the present invention may be performed by a battery control device located within a battery system including a plurality of batteries. Here, the battery control device may correspond to an upper control device that interfaces with the battery management devices of each battery, and may correspond to, for example, a BSC, EMS, or PMS that interfaces with a plurality of BMSs.

[0086] The battery control device can set a reference voltage based on the status values ​​of each battery when the batteries are disconnected from the parallel connection (S410). Here, when an event requiring the batteries to be connected in parallel occurs (e.g., 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 of the event occurrence.

[0087] The battery control device can receive status values ​​of each battery from each battery management device (e.g., BMS). Here, the battery status values ​​can include one or more of a voltage value and a SOC value for each battery.

[0088] The battery control device can check the operation mode of the battery system and set a reference voltage based on a reference voltage setting criterion defined in correspondence with the operation mode.

[0089] The operating mode may include one or more of a charge mode, a discharge mode, and a charge-discharge mixed mode. Here, the battery control device can determine whether the current battery system is operating in the charge mode, the discharge mode, or the charge-discharge mixed mode.

[0090] The battery control unit can receive information regarding 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, the battery control unit can receive information regarding the operating mode from its higher-level control unit, such as an EMS or PMS.

[0091] The battery control device can determine the current operating mode of the battery system based on charge / discharge schedule information including time-interval operation modes. Here, the battery control device can receive charge / discharge schedule information from a higher-level control device.

[0092] For example, the charge / discharge schedule information may include data defining an operation mode for each time interval, such as [00:00 ~ 11:00 ; discharge mode], [11:00 ~ 15:00 ; charge mode], [15:00 ~ 17:00 ; charge / discharge mixed mode], [17:00 ~ 24:00 ; discharge mode]. The battery control device may receive the charge / discharge schedule information from the upper control device and store it in a storage device. If a parallel connection event occurs at a specific time, the battery control device may use the charge / discharge schedule information to identify an operation mode corresponding to the time.

[0093] The reference voltage setting criteria for each of the operating modes can be defined differently.

[0094] In charge mode, the lowest voltage value among the voltage values ​​of the batteries may be set as the reference voltage, and in discharge mode, the highest voltage value among the voltage values ​​of the batteries may be set as the reference voltage.

[0095] 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 may correspond to the battery with the largest number of other batteries that can be connected in parallel.

[0096] The battery control device can select, among the batteries, target batteries having a reference voltage set in S410 and a voltage within a preset range (S420).

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

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

[0099] The battery control device can control the target batteries selected in S420 to be connected in parallel with each other (S430).

[0100] Specifically, the battery control device can control each of the target batteries to be connected to the DC link. Here, the battery control device can control the target batteries to be connected in parallel by transmitting a switch control signal to the battery management device of each of the target batteries so that a switch connecting the battery and the DC link is turned into a closed state.

[0101]

[0102] Figure 5 is an operational flowchart of a battery control method according to another embodiment of the present invention.

[0103] When a parallel connection event occurs, the battery control device can check the current operating mode of the battery system (S510). Here, the battery control device can check whether the current battery system is operating in either charge mode, discharge mode, or charge-discharge mixed mode.

[0104] The battery control device can determine the current operation mode by checking the current operation mode through the upper control device, or by using the charge / discharge schedule information and current time received from the upper control device.

[0105] The battery control device can set the reference voltage based on the operation mode identified in S510.

[0106] If the current operation mode of the battery system is the charging mode (Y of S521), the battery control device can set the lowest voltage value (Vmin) among the voltage values ​​of the batteries as the reference voltage (Vref) (S531). For example, if the voltage values ​​of the batteries (Bat #1 to Bat #5) are [755 V, 805 V, 810 V, 795 V, 765 V], the reference voltage value can be set to 755 V.

[0107] If the current operation mode of the battery system is the discharge mode (Y of S522), the battery control device can set the highest voltage value (Vmax) among the voltage values ​​of the batteries as the reference voltage (Vref) (S532). For example, if the voltage values ​​of the batteries (Bat #1 to Bat #5) are [755 V, 805 V, 810 V, 795 V, 765 V], the reference voltage value can be set to 810 V.

[0108] If the current operating mode of the battery system is a charge / discharge mixed mode (Y of S523), the battery control device can select a specific battery among the batteries as a reference battery (Bat_ref) and set the voltage value (Vbat_ref) of the reference battery 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).

[0109] Hereinafter, with reference to FIG. 6, a method for setting a reference voltage in a charge / discharge mixed mode according to an embodiment of the present invention will be described in detail.

[0110] FIG. 6 is a reference table for explaining a method for setting a reference voltage in a charge / discharge mixed mode according to an embodiment of the present invention, and is an example of a voltage difference between batteries.

[0111] The battery control device can calculate, for each battery, a difference value between the state values ​​of the batteries and other batteries. For example, if the voltage values ​​of each of the batteries (Bat #1 to Bat #5) are [755 V, 805 V, 803 V, 810 V, 765 V], the battery control device can calculate, for each of the batteries (Bat #1 to Bat #5), a difference value between the voltage values ​​of the batteries and other batteries, as illustrated in FIG. 6.

[0112] Thereafter, the battery control device can determine, for each battery, the number of other batteries that can be connected in parallel. Here, the battery control device can determine, for each battery, the number of other batteries that have voltage values ​​that differ from its own state value within a predetermined range, thereby determining the number of other batteries that can be connected in parallel.

[0113] Thereafter, 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.

[0114] For example, if the voltage difference value between batteries (Bat #1 to Bat #5) is calculated as in Fig. 6 and the predefined voltage range for selecting a reference battery is ±5 V, the number of batteries that can be connected in parallel for each of the batteries (Bat #1 to Bat #5) can be determined as 0, 2, 1, 1, and 0. Here, 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, 805 V, as the reference voltage (Vref).

[0115] Referring again to FIG. 5, the battery control device can select target batteries having a reference voltage and a voltage within a preset range in S531 to S533 (S540).

[0116] For example, if the voltage values ​​of each of the batteries (Bat #1 to Bat #5) are [755 V, 805 V, 810 V, 795 V, 765 V] and the current operation mode of the battery system is the charging mode, the reference voltage value can be set to 755 V (S531). Here, if the predefined voltage range for target battery selection is 10 V, the battery control device can determine Bat #1 and Bat #5 as the target batteries.

[0117] For another example, if the voltage values ​​of each of the batteries (Bat #1 to Bat #5) are [755 V, 805 V, 810 V, 795 V, 765 V] and the current operation mode of the battery system is the discharge mode, the reference voltage value can be set to 810 V (S532). Here, if the predefined voltage range for target battery selection is 10 V, the battery control device can determine Bat #2 and Bat #3 as the target batteries.

[0118] For another example, if the voltage values ​​of each of the batteries (Bat #1 to Bat #5) are [755 V, 805 V, 803 V, 810 V, 765 V] and the current battery system operation mode is a charge / discharge mixed mode, the reference voltage value can be set to 805 V (S533). Here, if the predefined voltage range for target battery selection is ±5 V, the battery control device can determine Bat #2, Bat #3, and Bat #4 as target batteries.

[0119] The battery control device can control the target batteries selected in S540 to be connected in parallel with each other (S550).

[0120] Specifically, the battery control device can control each of the target batteries to be connected to the DC link. Here, the battery control device can control the target batteries to be connected in parallel by transmitting a switch control signal to the battery management device of each of the target batteries so that a switch connecting the battery and the DC link is turned into a closed state.

[0121] Thereafter, the battery system can operate according to the current operating mode while the target batteries are connected to the DC link.

[0122] The battery control device can perform active balancing control based on the voltage difference between the target battery (online battery) and the remaining batteries (offline batteries) during the operation of the battery system (S560).

[0123] Specifically, the battery control device can monitor the voltage difference between the target batteries and the offline batteries during the process of charging or discharging the target batteries according to the operating mode. Here, the battery control device can connect the offline batteries, of which the voltage difference with the target batteries falls within a preset range, to a DC link and connect them in parallel with the target batteries.

[0124] Hereinafter, with reference to FIGS. 7 to 9, an active balancing method for each operation mode according to an embodiment of the present invention will be described.

[0125]

[0126] FIG. 7 is a graph for explaining an active balancing method in a charging mode according to an embodiment of the present invention.

[0127] When the voltage values ​​of each of the batteries (Bat #1 ~ Bat #5) are [755 V, 805 V, 810 V, 795 V, 765 V], the reference voltage value can be set to 755 V. Here, when the predefined voltage range for target battery selection is 10 V, the target batteries are determined as Bat #1 and Bat #5, and Bat #1 and Bat #5 are connected to the DC link.

[0128] As the battery system operates in charge mode, the voltage of Bat #1 and Bat #5 gradually increases from an average voltage of 760 V.

[0129] The battery control device can monitor the average voltage of the online batteries (Bat #1, #5) and the voltage difference between each of the offline batteries (Bat #2, #3, #4). Here, the battery control device can connect a battery among the offline batteries (Bat #2, #3, #4) whose voltage difference with the online batteries (Bat #1, #5) falls within a preset range to the DC link and switch it to the online state.

[0130] When the predefined voltage range for bringing an offline battery into an online state is ±1 V, the battery control unit can bring Bat #4 into an online state by connecting it to the DC link at time t1. Thereafter, the battery control unit can bring Bat #2 into an online state by connecting it to the DC link at time t2. Thereafter, the battery control unit can bring Bat #3 into an online state by connecting it to the DC link at time t3.

[0131] In charging mode, the lowest voltage value among the batteries is set as the reference voltage. Therefore, when the battery system starts operating, only batteries with lower voltage ranges can participate in the charging process. As charging progresses, the remaining batteries sequentially participate, until all batteries are fully charged.

[0132]

[0133] FIG. 8 is a graph for explaining an active balancing control method in discharge mode according to an embodiment of the present invention.

[0134] When the voltage values ​​of each of the batteries (Bat #1 to Bat #5) are [755 V, 805 V, 810 V, 795 V, 765 V], the reference voltage value can be set to 810 V. Here, when the predefined voltage range for target battery selection is 10 V, the target batteries are determined as Bat #2 and Bat #3, and Bat #2 and Bat #3 are connected to the DC link.

[0135] As the battery system operates in discharge mode, the voltages of Bat #2 and Bat #3 gradually decrease from an average voltage of 807.5 V.

[0136] The battery control device can monitor the average voltage of the online batteries (Bat #2, #3) and the voltage difference between each of the offline batteries (Bat #1, #4, #5). Here, the battery control device can connect a battery among the offline batteries (Bat #1, #4, #5) whose voltage difference with the online batteries (Bat #2, #3) falls within a preset range to the DC link and switch it to the online state.

[0137] When the predefined voltage range for bringing the offline battery into the online state is ±1 V, the battery control unit can bring Bat #4 into the online state by connecting it to the DC link at time t1. Then, the battery control unit can bring Bat #5 into the online state by connecting it to the DC link at time t2. Then, the battery control unit can bring Bat #1 into the online state by connecting it to the DC link at time t3.

[0138] In discharge mode, the highest voltage value among the batteries is set as the reference voltage. Therefore, when the battery system starts operating, only batteries with higher voltage ranges can participate in the discharge process. As the discharge process progresses, the remaining batteries sequentially participate, until all batteries are able to participate in the discharge process.

[0139]

[0140] FIG. 9 is a graph for explaining an active balancing control method in a charge / discharge mixed mode according to an embodiment of the present invention.

[0141] When the voltage values ​​of each of the batteries (Bat #1 to Bat #5) are [755 V, 805 V, 803 V, 810 V, 765 V], the reference voltage value can be set to 805 V. Here, when the predefined voltage range for target battery selection is ±5 V, the target batteries are determined as Bat #2, Bat #3, and Bat #4, and Bat #2, Bat #3, and Bat #4 are connected to the DC link.

[0142] As the battery system operates in mixed charge / discharge mode, the voltages of Bat #2, Bat #3, and Bat #4 may increase or decrease from the average voltage of 806 V.

[0143] The battery control device can monitor the average voltage of the online batteries (Bat #2, #3, #4) and the voltage difference between each of the offline batteries (Bat #1, #5). Here, the battery control device can connect a battery among the offline batteries (Bat #1, #5) whose voltage difference with the online batteries (Bat #2, #3, #4) falls within a preset range to the DC link and switch it to the online state.

[0144] When the predefined voltage range for bringing an offline battery into an online state is ±1 V, the battery control unit can bring Bat #5 into an online state by connecting it to the DC link at time t1. Thereafter, the battery control unit can bring Bat #1 into an online state by connecting it to the DC link at time t2.

[0145] In mixed charge / discharge mode, the voltage value of the battery with the largest number of parallel-connected batteries is set as the reference voltage. This allows the battery system to initiate charging as many batteries as possible without inrush current. As charging or discharging progresses, the remaining batteries sequentially participate in the charging / discharging process, ensuring that as many batteries as possible can participate in the charging / discharging process.

[0146]

[0147] Figure 10 is a block diagram of a battery control device according to an embodiment of the present invention.

[0148] The battery control device (1000) according to an embodiment of the present invention is positioned within a battery system and can be interoperable with the battery management devices of each battery. For example, the battery control device (1000) may correspond to a BSC, an EMS, or a PMS, or may be implemented as an integral part of any of these.

[0149] A battery control device (1000) may include at least one processor (1010), a memory (1020) that stores at least one command executed through the processor, and a transmission / reception device (1030) that is connected to a network and performs communication.

[0150] The at least one command may include: a command for checking the operation mode of the battery system; a command for setting a reference voltage based on a reference voltage setting criterion defined in correspondence with the checked operation mode; a command for selecting target batteries having a voltage within a preset range from the reference voltage; and a command for controlling the target batteries to be connected in parallel with each other.

[0151] The above operation mode may include one or more of a charge mode, a discharge mode, and a charge-discharge mixed mode.

[0152] The command for checking the operation mode of the above battery system may include a command for determining the current operation mode of the battery system based on charge / discharge schedule information including the operation mode by time interval.

[0153] The command for setting the reference voltage may include a command for setting the lowest voltage value among the voltage values ​​of the batteries as the reference voltage when the battery system is operating in a charging mode.

[0154] The command for setting the reference voltage may include a command for setting the highest voltage value among the voltage values ​​of the batteries as the reference voltage when the battery system operates in discharge mode.

[0155] The command for setting the reference voltage may include a command for setting the voltage value of a specific battery among the batteries as the reference voltage when the battery system operates in a charge / discharge mixed mode.

[0156] The command for setting the reference voltage may include, for each battery, a command for determining the number of other batteries whose voltage values ​​differ from its own voltage value within a preset range; and a command for setting the voltage value of the battery with the largest number of other batteries as the reference voltage.

[0157] The at least one command may further include a command to connect, in parallel with the target batteries, one or more batteries from which the parallel connection is disconnected, the voltage difference with respect to the target batteries falling within a preset range, during the process of charging or discharging the target batteries.

[0158] The command for controlling the target batteries to be connected in parallel with each other may include a command for transmitting a switch control signal to the battery management device of each of the target batteries so that a switch connecting the battery and the DC link is turned into a closed state.

[0159] The battery control device (1000) may further include an input interface device (1040), an output interface device (1050), a storage device (1060), etc. Each component included in the battery control device (1000) may be connected by a bus (1070) and communicate with each other.

[0160] Here, the processor (1010) may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. The memory (or storage device) may be composed of at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory may be composed of at least one of a read-only memory (ROM) and a random access memory (RAM).

[0161] The operations of the method according to an embodiment of the present invention can be implemented as a computer-readable program or code on a computer-readable recording medium. A computer-readable recording medium includes any type of recording device that stores data readable by a computer system. Furthermore, a computer-readable recording medium can be distributed across network-connected computer systems, allowing the computer-readable program or code to be stored and executed in a distributed manner.

[0162] While some aspects of the present invention have been described in the context of a device, they may also represent a description of a corresponding method, wherein a block or device corresponds to a method step or a feature of a method step. Similarly, aspects described in the context of a method may also be described as a corresponding block or item or a feature of a corresponding device. Some or all of the method steps may be performed by (or using) a hardware device, such as, for example, a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, one or more of the most significant method steps may be performed by such a device.

[0163] Although the present invention has been described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

Claims

1. A battery control device located within a battery system including a plurality of batteries, at least one processor; and A memory that stores at least one instruction to be executed through at least one processor, At least one of the above commands, A command to check the operation mode of the above battery system; A command to set a reference voltage based on a reference voltage setting criterion defined in correspondence with the identified operation mode; A command to select target batteries having a voltage within the above reference voltage and a preset range; and A battery control device comprising a command for controlling the target batteries to be connected in parallel with each other.

2. In claim 1, The above operation mode is, A battery control device comprising at least one of a charge mode, a discharge mode, and a charge-discharge mixed mode.

3. In claim 2, The command to check the operation mode of the above battery system is: A battery control device comprising a command for determining a current operation mode of a battery system based on charge / discharge schedule information including an operation mode by time interval.

4. In claim 1, The command to set the above reference voltage is: A battery control device, comprising a command to set the lowest voltage value among the voltage values ​​of the batteries as a reference voltage when the battery system is operating in a charging mode.

5. In claim 1, The command to set the above reference voltage is: A battery control device, comprising a command to set the highest voltage value among the voltage values ​​of the batteries as a reference voltage when the battery system operates in discharge mode.

6. In claim 1, The command to set the above reference voltage is: A battery control device, comprising a command to set the voltage value of a specific battery among the batteries as a reference voltage when the battery system operates in a charge / discharge mixed mode.

7. In claim 6, The command to set the above reference voltage is: For each battery, a command to determine the number of other batteries whose voltage values ​​differ from its own voltage value within a preset range; and A battery control device including a command to set the voltage value of the battery with the largest number of other batteries as the reference voltage.

8. In claim 1, At least one of the above commands, A battery control device further comprising a command to connect, in parallel with the target batteries, one or more batteries among which the parallel connection is disconnected, the voltage difference with respect to the target batteries falling within a preset range during the process of charging or discharging the target batteries.

9. In claim 1, The command to control the above target batteries to be connected in parallel with each other is: A battery control device comprising a command for transmitting a switch control signal to a battery management device of each of the target batteries so as to cause a switch connecting the battery and the DC link to be turned into a closed state.

10. A battery control method by a battery control device located in a battery system including a plurality of batteries, A step of checking the operation mode of the above battery system; A step of setting a reference voltage based on a reference voltage setting criterion defined in correspondence with the confirmed operation mode; A step of selecting target batteries having a voltage within the reference voltage and a preset range; and A battery control method comprising a step of controlling the target batteries to be connected in parallel with each other.

11. In claim 10, The above operation mode is, A battery control method comprising at least one of a charge mode, a discharge mode, and a charge-discharge mixed mode.

12. In claim 11, The step of checking the operation mode of the above battery system is: A battery control method, comprising a step of determining a current operation mode of a battery system based on charge / discharge schedule information including an operation mode by time interval.

13. In claim 10, The step of setting the above reference voltage is: A battery control method, comprising a command for setting the lowest voltage value among the voltage values ​​of the batteries as a reference voltage when the battery system is operating in a charging mode.

14. In claim 10, The step of setting the above reference voltage is: A battery control method, comprising the step of setting the highest voltage value among the voltage values ​​of the batteries as a reference voltage when the battery system operates in discharge mode.

15. In claim 10, The step of setting the above reference voltage is: A battery control method, comprising the step of setting the voltage value of a specific battery among the batteries as a reference voltage when the battery system operates in a charge / discharge mixed mode.

16. In claim 15, The step of setting the above reference voltage is: For each of the batteries, determining the number of other batteries whose voltage values ​​differ from its own voltage value within a preset range; and A battery control method, comprising the step of setting the voltage value of the battery having the largest number of other batteries as the reference voltage.

17. In claim 10, A battery control method further comprising a step of connecting, in parallel with the target batteries, one or more batteries from which the parallel connection is disconnected, the voltage difference with respect to the target batteries falling within a preset range during the process of charging or discharging the target batteries.

18. In claim 10, The step of controlling the above target batteries to be connected in parallel with each other is: A battery control method comprising the step of transmitting a switch control signal to a battery management device of each of the target batteries so as to cause a switch connecting a battery and a DC link to be switched to a closed state.

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