Apparatus and method for controlling battery

Abstract

An apparatus for controlling a battery according to one embodiment of the present invention is located in a battery system including a plurality of batteries, and may comprise: at least one processor; and memory storing at least one instruction that is executed through the at least one processor. The at least one instruction may comprise: an instruction for monitoring the voltages of online batteries, connected to a DC bus and being charged, during a charging process of the battery system; an instruction for disconnecting the connection between the DC bus and at least one battery, among the plurality of online batteries being charged, when the corresponding online battery satisfies a predefined target voltage, and thereby switching the corresponding online battery to an offline state; and an instruction for controlling cell balancing for at least one of the offline batteries switched to the offline state.

Description

Battery control device and method

[0001] This application claims the benefit of Korean Patent Application No. 10-2024-0066209, filed with the Korean Intellectual Property Office on May 22, 2024, and Korean Patent Application No. 10-2025-0050649, filed with the Korean Intellectual Property Office on April 18, 2025, the entire contents of which are incorporated herein by reference.

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

[0003] Secondary batteries are batteries that can be reused through 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] In general, a battery system has a disadvantage in that when one battery cell in a battery rack is fully charged, the charging process of the entire battery system, including the battery rack, is terminated even if the other battery cells are not fully charged, resulting in a decrease in the charging efficiency of the battery system.

[0006] An object of the present invention to solve the above problems is to provide a battery control device for improving the stability of a battery system.

[0007] Another object of the present invention to solve the above problems is to provide a battery control method using such a battery control device.

[0008] According to one embodiment of the present invention for achieving the above object, a battery control device is provided, which is located in a battery system including a plurality of batteries, and includes at least one processor and a memory storing at least one command executed by the at least one processor, wherein the at least one command includes a command for monitoring voltages of online batteries connected to a DC bus and being charged during a charging process of the battery system, a command for switching an online battery into an offline state by disconnecting its connection to the DC bus when at least one battery among the plurality of online batteries being charged satisfies a predefined target voltage, and a command for controlling cell balancing for at least one offline battery switched into an offline state.

[0009] Here, the command for controlling the cell balancing may include a command for controlling cell balancing of the online battery to be performed immediately after the at least one online battery is switched to an offline state.

[0010] More specifically, the command for controlling the cell balancing may include a command for controlling the battery management device connected to at least one offline battery to transmit a balancing mode switching signal so that the battery management device performs cell balancing of the offline battery.

[0011] Meanwhile, according to one embodiment, the command to switch to the offline state may include a command to check whether, among the plurality of online batteries being charged, one online battery satisfies a predefined target voltage, the online battery has reached the predefined target voltage again, and a command to transmit a switch control signal to a battery management device connected to the online battery to cut off the connection of the online battery to the DC bus, if the online battery has reached the predefined target voltage again.

[0012] Additionally, the command to switch to the offline state may include a command to transmit a charge speed control signal to a battery management device connected to the online battery to lower the charge speed of the online battery when the online battery first reaches a predefined target voltage, and a command to transmit a recalibration signal to the battery management device connected to the online battery to readjust the charge state of the online battery.

[0013] According to another embodiment, the command to switch to the offline state may include a command to check whether any one of the plurality of online batteries being charged satisfies a predefined target voltage, a command to transmit a charge speed control signal to a battery management device connected to the online battery to lower the charge speed of the online battery if the online battery satisfies the predefined target voltage, a command to transmit a recalibration signal to the battery management device connected to the online battery to readjust the charge state of the online battery, and a command to transmit a switch control signal to the battery management device connected to the online battery to cut off the connection of the online battery to the DC bus if the online battery is in a fully charged state.

[0014] Meanwhile, the command to switch to the offline state can be performed until all of the plurality of online batteries are switched to the offline state.

[0015] Additionally, the at least one command may further include a command to bring at least one offline battery into an online state during a discharging process of the battery system.

[0016] At this time, the command to switch to the online state may include a command to switch to the online state at least one of the offline batteries for which cell balancing has been completed.

[0017] Additionally, the command to switch to the online state may include, when the battery system is in discharge mode, a command to switch a target offline battery to the online state, and thereafter, a command to sequentially switch a plurality of offline batteries, excluding the target offline battery, to the online state.

[0018] Here, the target offline battery may be the battery that is switched to an offline state last among the plurality of online batteries.

[0019] Additionally, the command for sequentially switching the plurality of offline batteries to an online state may include a command for monitoring a voltage of at least one offline battery, a command for obtaining a reference voltage of at least one online battery, a command for comparing a difference between the reference voltage of the online battery and the voltage of the offline battery, and a command for switching at least one offline battery to an online state when the difference falls within a predefined voltage range.

[0020] Meanwhile, the command to switch to the online state can be performed until all of the plurality of offline batteries are switched to the online state.

[0021]

[0022] According to one embodiment of the present invention for achieving the above-described other object, a battery control method by a battery control device located in a battery system including a plurality of batteries includes the steps of: monitoring voltages of online batteries connected to a DC bus and being charged during a charging process of the battery system; switching the online battery to an offline state by disconnecting the connection to the DC bus when at least one battery among the plurality of online batteries being charged satisfies a predefined target voltage; and controlling cell balancing for at least one of the offline batteries switched to an offline state.

[0023] Here, the step of controlling the cell balancing may include a step of controlling that the cell balancing of the online battery is performed immediately after the at least one online battery is switched to an offline state.

[0024] More specifically, the step of controlling the cell balancing may include a step of transmitting a balancing mode switching signal to a battery management device connected to at least one of the offline batteries, thereby controlling cell balancing of the offline battery to be performed by the battery management device.

[0025] Meanwhile, according to one embodiment, the step of switching to the offline state may include the step of, when any one of the plurality of online batteries being charged satisfies a predefined target voltage, checking whether the online battery has reached the predefined target voltage again, and, when the online battery has reached the predefined target voltage again, the step of transmitting a switch control signal to a battery management device connected to the online battery to cut off the DC bus connection of the online battery.

[0026] Additionally, the step of switching to the offline state may include the step of transmitting a charge speed control signal to a battery management device connected to the online battery to lower the charge speed of the online battery when the online battery first reaches a predefined target voltage, and the step of transmitting a recalibration signal to the battery management device connected to the online battery to readjust the charge state of the online battery.

[0027] According to another embodiment, the step of switching to an offline state may include the steps of: checking whether any one of the plurality of online batteries being charged satisfies a predetermined target voltage; if the online battery satisfies the predetermined target voltage, transmitting a charge speed control signal to a battery management device connected to the online battery to lower a charge speed of the online battery; transmitting a recalibration signal to the battery management device connected to the online battery to readjust a charge state of the online battery; and if the online battery is in a fully charged state, transmitting a switch control signal to the battery management device connected to the online battery to cut off a connection of the online battery to a DC bus.

[0028] The step of switching to the offline state may be performed until all of the plurality of online batteries are switched to the offline state.

[0029] Additionally, the battery control method may further include a step of switching at least one offline battery to an online state during a discharging process of the battery system.

[0030] At this time, the step of switching to the online state may include a step of switching to the online state at least one of the offline batteries for which cell balancing has been completed.

[0031] Additionally, the step of switching to the online state may include a step of switching a target offline battery to the online state when the battery system is in a discharge mode, and a step of sequentially switching a plurality of offline batteries, excluding the target offline battery, to the online state thereafter.

[0032] Here, the target offline battery may be the battery that is switched to an offline state last among the plurality of online batteries.

[0033] Additionally, the step of sequentially switching the plurality of offline batteries to an online state may include the step of monitoring a voltage of at least one offline battery, the step of obtaining a reference voltage of at least one online battery, the step of comparing a difference between the reference voltage of the online battery and the voltage of the offline battery, and the step of switching at least one offline battery to an online state when the difference falls within a predefined voltage range.

[0034] Meanwhile, the step of switching to the online state can be performed until all of the plurality of offline batteries are switched to the online state.

[0035] According to the above-described embodiment of the present invention, the battery control device can improve the charging efficiency of the battery system by switching the state of an online battery that has reached a target voltage to an offline state in a charging mode, thereby allowing the charging of batteries in an online state other than the online battery to continue.

[0036] In addition, according to an embodiment of the present invention, the battery control device can perform additional cell-by-cell balancing on an offline battery that has completed charging at the battery level, thereby minimizing deviation between cells within the battery, thereby enabling precise battery charging and discharging control.

[0037] Figure 1 is a block diagram of a typical energy storage system.

[0038] Figure 2 is a block diagram of a battery system according to an embodiment of the present invention.

[0039] Figure 3 is an operation flowchart of a battery control method in a charging process according to one embodiment of the present invention.

[0040] Figure 4 is an operational flowchart of a battery control method during a charging process according to another embodiment of the present invention.

[0041] FIG. 5 is a reference diagram for explaining a battery control method during a charging process according to an embodiment of the present invention.

[0042] Figure 6 is an operation flowchart of a battery control method in a discharge process according to an embodiment of the present invention.

[0043] Figure 7 is a reference diagram for explaining a battery control method during a discharge process according to an embodiment of the present invention.

[0044] Figure 8 is a block diagram of a battery control device according to an embodiment of the present invention.

[0045] 100: Battery 200: Battery Management Device

[0046] 300: Battery control unit 810: Processor

[0047] 820: Memory 830: Transmitter / Receiver

[0048] 840: Input interface device 850: Output interface device

[0049] 860: Storage device

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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 exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0054] 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.

[0055]

[0056] Some terms used in this specification are defined as follows:

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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 [%].

[0062]

[0063] Figure 1 is a block diagram of a typical energy storage system.

[0064] 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.

[0065] 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 under its control, and based on the monitoring results, calculates the battery's SOC (Status Of Charge) and controls charging and discharging.

[0066] 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.

[0067] 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.

[0068] 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 bus (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.

[0069]

[0070] Figure 2 is a block diagram of a battery system according to an embodiment of the present invention.

[0071] Referring to FIG. 2, 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).

[0072] The battery (100) may be a battery assembly comprising a plurality of unit cells electrically connected to each other. For example, 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.

[0073] 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 bus and connected in parallel with another battery.

[0074] Each of the batteries (100) may include a switch positioned at the input / output terminal. When the switch is switched from a closed state to an open state, the electrical connection with the DC bus is cut off, thereby releasing the parallel connection with other batteries. Conversely, when the switch of the battery (100) is switched from an open state to a closed state, the battery (100) is electrically connected to the DC bus, thereby allowing the battery to be connected in parallel with other batteries.

[0075] 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). More specifically, the battery management device (200) can control charging and discharging of the battery and diagnose whether battery cells are faulty based on the status information of the battery. Here, the status information can include at least one of a voltage value and a SOC value of the battery and a voltage value and a SOC value of each of the unit cells included in the battery.

[0076] The battery management device (200) can control the operation of a switch provided at the input / output terminal of the battery (100).

[0077] 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.

[0078] The battery control device (300) can monitor and control the operating status of each of the battery management devices (200).

[0079] The battery control device (300) may correspond to a BSC (Battery Section Controller), an EMS (Energy Management System), or a PMS (Power Management System).

[0080] The battery control device (300) monitors the voltage of the online battery and the voltage of the offline battery during the charging and discharging process of at least one online battery by the battery management device (200), and can sequentially disconnect batteries that have reached a predetermined target voltage from the DC bus.

[0081] The battery control device (300) can perform a control process defined in response to the operation mode of the battery system.

[0082] The battery control device (300) monitors the voltage of each battery during the process of charging the batteries while they are connected in parallel to the DC bus (online state), and can sequentially remove batteries that have reached a predetermined target voltage from the DC bus.

[0083] Thereafter, the battery control device (300) can reconnect the selected target battery to the DC bus and bring it online.

[0084]

[0085] Figure 3 is an operation flowchart of a battery control method in a charging process according to one embodiment of the present invention.

[0086] Referring to FIG. 3, 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. Here, the battery control device may be an upper control device that interfaces with battery management devices corresponding to each of a plurality of batteries. Furthermore, the plurality of batteries may be provided in an online state during initialization.

[0087] The battery control device can monitor the charge voltage of each battery connected in parallel to the DC bus and in an online state (S310). For example, the battery control device can receive the voltage of each battery or the voltage of each unit cell from the battery management devices corresponding to each battery in an online state.

[0088] The battery control device can determine whether, among the batteries in the online state, a battery has reached a predefined target voltage (S320). More specifically, the battery control device can determine whether, among the voltage values ​​of the unit cells contained in a specific battery in the online state, the maximum voltage value reaches the target voltage.

[0089] Here, if there is a battery among the online batteries that has reached a predefined target voltage (Yes in S320), the battery control device can determine whether the battery has reached the target voltage again (S330). For example, the battery control device can count information on batteries that have reached the target voltage or receive charging speed information from a battery management device corresponding to the battery to determine whether the battery has reached the target voltage again.

[0090] According to one embodiment, if the corresponding battery is not a battery that has reached the target voltage again (No in S330), in other words, if the corresponding battery is a battery that has reached the target voltage for the first time, the battery control device may transmit a charge speed control signal to the battery management device corresponding to the corresponding battery (S340). Accordingly, the battery management device may adjust the charge voltage of the corresponding battery in order to lower the charge speed (C-rate) of the corresponding battery. For example, if any one of the batteries in the online state that is being charged at a charge speed of 0.5 C-rate reaches a predefined target voltage, the battery control device may transmit a charge speed control signal to the battery management device corresponding to the corresponding battery so that the corresponding battery is charged at a 0.05 C-rate. Accordingly, the battery management device may lower the charge voltage of the corresponding battery in order to lower the charge speed (C-rate) of the corresponding battery. Here, the predefined target voltage may be 3.6 V.

[0091] Thereafter, the battery control unit may transmit a recalibration signal to the battery management unit of the corresponding battery to readjust the state of charge of the corresponding battery (S350). Accordingly, the state of charge of the corresponding battery may be readjusted.

[0092] Afterwards, the battery control device can return to step S310 and continue to monitor the charging voltage of the batteries in the online state.

[0093] Meanwhile, according to another embodiment, if the corresponding battery is a battery that has reached the target voltage again (Yes in S330), the battery control device may transmit a switch control signal to a battery management device corresponding to the corresponding battery (S360). Accordingly, the battery management device may switch the switch connecting the corresponding battery to the DC bus to an open state. Accordingly, the corresponding battery may be disconnected from the DC bus and maintained in an offline state. At this time, while steps S320 to S360 are being performed, batteries in an online state, excluding the corresponding battery, may be continuously charged at a preset charging rate (e.g., 0.5 C-rate) by the corresponding battery management devices until the preset target voltage is reached.

[0094] Thereafter, the battery control device can transmit a cell balancing mode switching signal to the battery management device of the corresponding battery in the offline state (S370). For example, the battery control device can transmit a mode switching signal to the battery management device corresponding to the corresponding battery so that the corresponding battery is switched to the cell balancing mode when a preset time has elapsed based on the time at which the corresponding battery is switched to the offline state. Accordingly, the corresponding battery in the offline state can perform cell balancing under the control of the battery management device connected to the corresponding battery. For example, the preset time may be 10 minutes. However, without being limited to what has been disclosed, the battery control device can also transmit the cell balancing mode switching signal to the battery management device managing the corresponding battery so that cell balancing can be performed as soon as the corresponding battery is disconnected from the DC bus, that is, so that cell balancing can be performed immediately after the corresponding battery is switched to the offline state.

[0095] Afterwards, the battery control device can check whether the battery is the last battery that is online (S380).

[0096] At this time, if the battery that has reached the target voltage is not the last online battery (No in S380), the battery control device can repeat steps S310 to S380 until the last online battery.

[0097] In a typical battery system, when a specific cell voltage within a single battery reaches a predetermined target voltage during the charging process of multiple batteries, the system determines that the battery has met the target voltage and terminates the charging process. Consequently, charging of other batteries, even if they fail to reach the target voltage, is halted by the system, resulting in reduced system efficiency.

[0098] In addition, during the charging process of multiple batteries, there is a disadvantage in that the voltage deviation between unit cells within the battery is greater the first battery to reach the predefined target voltage.

[0099] Meanwhile, a battery control device according to an embodiment of the present invention can switch a battery among online batteries that reaches a predetermined target voltage to an offline state, and continuously perform charging so that a plurality of online batteries excluding the battery are charged to the target voltage.

[0100] Additionally, the battery control device according to an embodiment of the present invention can transmit a balancing execution signal to the battery management device of an offline battery that has reached a target voltage. Accordingly, the offline battery is subjected to cell balancing by the battery management device, thereby minimizing voltage deviation between cells, thereby improving the charging efficiency of the battery system.

[0101]

[0102] Figure 4 is an operational flowchart of a battery control method during a charging process according to another embodiment of the present invention.

[0103] Referring to FIG. 4, the battery control device can monitor the charging voltage of each of the batteries connected in parallel to the DC bus and in an online state (S410).

[0104] The battery control device can determine whether, among the batteries in the online state, any battery has reached a predefined target voltage (S420). More specifically, the battery control device can determine whether, among the voltage values ​​of the unit cells contained in a specific battery in the online state, the maximum voltage value reaches the target voltage.

[0105] At this time, if there is a battery among the online batteries that has reached a predefined target voltage (Yes in S420), the battery control device can transmit a charging speed control signal to the battery management device corresponding to the battery (S430). Accordingly, the battery management device can lower the charging voltage of the battery so that the charging speed (C-rate) of the battery is lowered.

[0106] Thereafter, the battery control unit may transmit a recalibration signal to the battery management unit of the corresponding battery to readjust the state of charge of the corresponding battery (S440). Accordingly, the state of charge of the corresponding battery may be readjusted.

[0107] Thereafter, the battery control device can monitor the charging state of the battery being charged (S450). At this time, if the battery reaches a full charge state (S460), the battery control device can transmit a switch control signal to a battery management device corresponding to the battery (S470). Accordingly, the battery management device can open the switch connecting the battery and the DC bus. Accordingly, the battery can be disconnected from the DC bus and maintained in an offline state. At this time, while steps S420 to S470 are being performed, batteries in an online state, excluding the battery in question, can be continuously charged at a preset charging rate (e.g., 0.5 C-rate) by the corresponding battery management devices.

[0108] Thereafter, the battery control device can transmit a cell balancing mode switching signal to the battery management device of the corresponding battery in the offline state (S480). For example, the battery control device can transmit a mode switching signal to the battery management device corresponding to the corresponding battery so that the corresponding battery is switched to the cell balancing mode when a predetermined time has elapsed from the time when the corresponding battery is switched to the offline state. Accordingly, the corresponding battery in the offline state can perform cell balancing under the control of the battery management device connected to the corresponding battery. For example, the predetermined time may be 10 minutes. However, without being limited to what has been disclosed, the battery control device can also transmit the cell balancing mode switching signal to the battery management device managing the corresponding battery so that cell balancing can be performed as soon as the corresponding battery is disconnected from the DC bus, i.e., so that cell balancing can be performed immediately after the corresponding battery is switched to the offline state.

[0109] Afterwards, the battery control device can check whether the battery is the last battery that is online (S490).

[0110] At this time, if the battery that has reached the target voltage is not the last online battery (No in S490), the battery control device can repeat steps S410 to S480 until the last online battery.

[0111]

[0112] FIG. 5 is a reference diagram for explaining a battery control method during a charging process according to an embodiment of the present invention.

[0113] Hereinafter, with reference to FIG. 5, a battery control method in a charging mode according to an embodiment of the present invention will be described using a battery system including four battery racks connected in parallel as an example.

[0114] The battery control unit can monitor the voltage of each of the battery racks (Rack #1 to #4) that are being charged online.

[0115] According to an embodiment, at time t1, if the maximum voltage value (hereinafter, maximum cell voltage value) among the voltage values ​​of the unit cells included in Rack #1 reaches a target voltage (e.g., 3.6 V), the battery control device may, at time t1, disconnect Rack #1 from the DC bus and switch it to an offline state. Thereafter, the battery control device may transmit a cell balancing mode switching signal to the battery management device connected to Rack #1. Accordingly, Rack #1 may be cell balanced by the battery management device.

[0116] Thereafter, at time t2, when the maximum cell voltage value of Rack #2 reaches the target voltage, the battery control unit can, at time t2, disconnect Rack #2 from the DC bus and switch it to an offline state. At this time, the battery control unit can transmit a cell balancing mode switching signal to the battery management unit connected to Rack #2. Accordingly, Rack #2 can be cell balanced by the battery management unit.

[0117] Thereafter, at time t3, when the maximum cell voltage value of Rack #4 reaches the target voltage, the battery control unit can, at time t3, disconnect Rack #4 from the DC bus and switch it to an offline state. At this time, the battery control unit can transmit a cell balancing mode switching signal to the battery management unit connected to Rack #4. Accordingly, Rack #4 can be cell balanced by the battery management unit.

[0118] Thereafter, at time t4, if the maximum cell voltage value of Rack #3 reaches the target voltage, the battery control unit may, at time t4, disconnect Rack #3 from the DC bus and switch it to an offline state. At this time, the battery control unit may transmit a cell balancing mode switching signal to the battery management unit connected to Rack #3. Accordingly, Rack #3 may be cell balanced by the battery management unit.

[0119] Afterwards, when the charging process is interrupted, the battery control device can wait until the discharge process of the battery system is in progress.

[0120]

[0121] Figure 6 is an operation flowchart of a battery control method in discharge mode according to an embodiment of the present invention.

[0122] Referring to Figure 6, when the battery system switches to discharge mode while all batteries are offline, the battery control device may select one of the multiple offline batteries as the target battery (S610). For example, the target battery may be the last battery among the multiple online batteries to switch to offline mode.

[0123] Thereafter, the battery control device can bring the offline target battery back online by reconnecting it to the DC bus (S620). More specifically, the battery control device can transmit a switch control signal to the battery management device of the target battery so that the switch connecting the offline battery and the DC bus is turned on (closed). Accordingly, the target battery can be reconnected to the DC bus.

[0124] Thereafter, the battery control device can monitor the reference voltage of the battery system and the voltages of the remaining offline batteries, excluding the target battery, during the process of discharging the online battery (S630). Here, the reference voltage of the battery system can be defined as the average voltage of the online batteries.

[0125] Thereafter, the battery control device can check whether, among the offline batteries, there is an offline battery whose voltage difference from the reference voltage of the battery system is within a predefined range (S640).

[0126] If there is a specific offline battery whose voltage difference from the reference voltage of the battery system is within a predefined range (Yes in S640), in other words, if the average voltage difference between the specific offline battery and the online batteries is within a predefined range, the battery control device can switch the offline battery to an online state. More specifically, the battery control device can transmit a switch control signal to the battery management device of the offline battery to turn on (close) the switch connecting the offline battery and the DC bus. Accordingly, the offline battery can be reconnected to the DC bus and switched to an online state.

[0127] Meanwhile, if the battery that has reached the target voltage is not the last battery in the offline state (No in S660), the battery control device may repeat steps S610 to S650 until the last battery in the offline state is switched to the online state.

[0128]

[0129] Figure 7 is a reference diagram for explaining a battery control method in discharge mode according to an embodiment of the present invention.

[0130] Hereinafter, with reference to FIG. 7, a battery control method in a discharge mode according to an embodiment of the present invention will be described using a battery system including four battery racks connected in parallel as an example.

[0131] According to an embodiment, at time t5, when the battery system switches to the discharge mode, the battery control device can switch Rack #3, which was last switched to the offline state during the charging process among the offline battery racks (Rack #1 to #4), to the online state.

[0132] Thereafter, the battery control device can monitor the voltage of each of the battery racks (Rack #1 to #4) during the discharge process of Rack #3, which has been switched online. Here, the battery racks (Rack #1 to #4) may be racks in which cell balancing has been completed.

[0133] Afterwards, when the voltage of Rack #3, which is online, gradually decreases and reaches the voltage of Rack #4 at time t6, the battery control unit can switch Rack #4, which is offline at time t6, to online.

[0134] Afterwards, when the voltage of Rack #3 and Rack #4, which are online, gradually decreases and reaches the voltage of Rack #2 at time t7, the battery control unit can switch Rack #2, which is offline at time t7, to online.

[0135] Afterwards, the voltages of Rack #2, Rack #3, and Rack #4, which are online, gradually decrease and reach the voltage of Rack #1 at time t8, so that the battery control unit can switch Rack #1, which is offline at time t8, to online.

[0136] Accordingly, all battery racks (Rack #1 to #4) that have been brought online can be discharged by being connected in parallel to the DC bus.

[0137]

[0138] Figure 8 is a block diagram of a battery control device according to an embodiment of the present invention.

[0139] Referring to FIG. 8, a battery control device according to an embodiment of the present invention may include at least one processor (810), a memory (820) that stores at least one command executed through the processor, and a transmission / reception device (830) that is connected to a network and performs communication.

[0140] The at least one command includes a command for monitoring voltages of online batteries connected to a DC bus and being charged during a charging process of the battery system, a command for switching the online battery to an offline state by disconnecting the connection to the DC bus when at least one battery among the plurality of online batteries being charged satisfies a predefined target voltage, and a command for controlling cell balancing for at least one offline battery switched to an offline state.

[0141] Here, the command controlling the cell balancing may include a command controlling cell balancing to be performed as soon as the at least one battery is switched to an offline state.

[0142] More specifically, the command for controlling the cell balancing may include a command for controlling the battery management device connected to at least one offline battery to transmit a balancing mode switching signal so that the battery management device performs cell balancing of the offline battery.

[0143] Meanwhile, according to one embodiment, the command to switch to the offline state may include a command to check whether, among the plurality of online batteries being charged, one online battery satisfies a predefined target voltage, the online battery has reached the predefined target voltage again, and a command to transmit a switch control signal to a battery management device connected to the online battery to cut off the connection of the online battery to the DC bus, if the online battery has reached the predefined target voltage again.

[0144] Additionally, the command to switch to the offline state may include a command to transmit a charge speed control signal to a battery management device connected to the online battery to lower the charge speed of the online battery when the online battery first reaches a predefined target voltage, and a command to transmit a recalibration signal to the battery management device connected to the online battery to readjust the charge state of the online battery.

[0145] According to another embodiment, the command to switch to the offline state may include a command to check whether any one of the plurality of online batteries being charged satisfies a predefined target voltage, a command to transmit a charge speed control signal to a battery management device connected to the online battery to lower the charge speed of the online battery if the online battery satisfies the predefined target voltage, a command to transmit a recalibration signal to the battery management device connected to the online battery to readjust the charge state of the online battery, and a command to transmit a switch control signal to the battery management device connected to the online battery to cut off the connection of the online battery to the DC bus if the online battery is in a fully charged state.

[0146] Meanwhile, the command to switch to the offline state can be performed until all of the plurality of online batteries are switched to the offline state.

[0147] Additionally, the at least one command may further include a command to bring at least one offline battery into an online state during a discharging process of the battery system.

[0148] At this time, the command to switch to the online state may include a command to switch to the online state at least one of the offline batteries for which cell balancing has been completed.

[0149] Additionally, the command to switch to the online state may include, when the battery system is in discharge mode, a command to switch a target offline battery to the online state, and thereafter, a command to sequentially switch a plurality of offline batteries, excluding the target offline battery, to the online state.

[0150] Here, the target offline battery may be the battery that is switched to an offline state last among the plurality of online batteries.

[0151] Additionally, the command for sequentially switching the plurality of offline batteries to an online state may include a command for monitoring a voltage of at least one offline battery, a command for obtaining a reference voltage of at least one online battery, a command for comparing a difference between the reference voltage of the online battery and the voltage of the offline battery, and a command for switching at least one offline battery to an online state when the difference falls within a predefined voltage range.

[0152] Meanwhile, the command to switch to the online state can be performed until all of the plurality of offline batteries are switched to the online state.

[0153] The battery control device (800) may further include an input interface device (840), an output interface device (850), a storage device (860), etc. Each component included in the battery control device (700) may be connected by a bus (870) and communicate with each other.

[0154] Here, the processor (810) 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 (820) or storage device (860) may be configured with at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory (820) may be configured with at least one of a read-only memory (ROM) and a random access memory (RAM).

[0155] 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.

[0156] 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.

[0157] 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, During the charging process of the above battery system, a command to monitor the voltage of online batteries connected to the DC bus and being charged; A command to disconnect the connection of the DC bus of the online battery and switch it to an offline state when at least one battery among the plurality of online batteries being charged satisfies a predetermined target voltage, and A battery control device comprising commands for controlling cell balancing of at least one offline battery that has been switched to an offline state.

2. In claim 1, The command controlling the above cell balancing is: A battery control device comprising a command for controlling cell balancing of the online battery to be performed immediately after at least one of the online batteries is switched to an offline state.

3. In claim 1, The command controlling the above cell balancing is: A battery control device comprising a command for controlling cell balancing of the offline battery by transmitting a balancing mode switching signal to a battery management device connected to at least one of the offline batteries, thereby performing cell balancing of the offline battery by the battery management device.

4. In claim 1, The command to switch to the above offline state is: A command to check whether, among the plurality of online batteries being charged, one online battery satisfies a predefined target voltage, the online battery has reached the predefined target voltage again; and A battery control device, comprising a command to transmit a switch control signal to a battery management device connected to the online battery when the online battery has re-reached a predetermined target voltage, thereby disconnecting the connection of the online battery to the DC bus.

5. In claim 4, The command to switch to the above offline state is: A command to transmit a charge speed control signal to a battery management device connected to the online battery to lower the charge speed of the online battery when the online battery first reaches a predetermined target voltage, and A battery control device, comprising a command for transmitting a recalibration signal to the battery management device connected to the online battery to readjust the state of charge of the online battery.

6. In claim 1, The command to switch to the above offline state is: A command to check whether any one of the plurality of online batteries being charged satisfies a predetermined target voltage; When the online battery satisfies a predetermined target voltage, a command to transmit a charge speed control signal to a battery management device connected to the online battery to lower the charge speed of the online battery; A command for transmitting a recalibration signal to the battery management device connected to the online battery to readjust the charge state of the online battery, and A battery control device, comprising a command to transmit a switch control signal to a battery management device connected to the online battery when the online battery is fully charged, thereby cutting off the connection of the online battery to the DC bus.

7. In claim 1, The command to switch to the above offline state is: A battery control device that is performed until all of the above-mentioned multiple online batteries are switched to an offline state.

8. In claim 1, A battery control device further comprising a command for switching at least one offline battery to an online state during a discharge process of the battery system.

9. In claim 8, The command to switch to the above online state is: A battery control device comprising a command for switching at least one offline battery, for which cell balancing has been completed, to an online state.

10. In claim 8, The command to switch to the above online state is: When the above battery system is in discharge mode, a command to bring the target offline battery into online state, and A battery control device including a command to sequentially switch a plurality of offline batteries, excluding the target offline battery, to an online state.

11. In claim 10, The above target offline battery is, A battery control device, which is the last battery among the above-mentioned plurality of online batteries to be switched to an offline state.

12. In claim 10, The command to sequentially bring the above multiple offline batteries into an online state is: A command to monitor the voltage of at least one of the above offline batteries, A command to obtain a reference voltage of at least one of the above online batteries, A command to compare the difference between the reference voltage of the online battery and the voltage of the offline battery, and A battery control device comprising a command to bring at least one of the offline batteries into an online state when the difference falls within a predefined voltage range.

13. In claim 8, The command to switch to the above online state is: A battery control device that is performed until all of the above-mentioned multiple offline batteries are switched to an online state.

14. A battery control method by a battery control device located in a battery system including a plurality of batteries, During the charging process of the above battery system, a step of monitoring the voltage of online batteries connected to the DC bus and being charged; A step of switching to an offline state by disconnecting the connection of the DC bus of the online battery when at least one battery among the plurality of online batteries being charged satisfies a predetermined target voltage; and A battery control method comprising the step of controlling cell balancing for at least one offline battery that has been switched to an offline state.

15. In claim 14, The step of controlling the above cell balancing is: A battery control method comprising a step of controlling cell balancing of the online battery to be performed immediately after at least one online battery is switched to an offline state.

16. In claim 14, The step of controlling the above cell balancing is: A battery control method comprising the step of transmitting a balancing mode switching signal to a battery management device connected to at least one of the offline batteries, thereby controlling cell balancing of the offline battery to be performed by the battery management device.

17. In claim 14, The steps to switch to the above offline state are: A step of checking whether, among the plurality of online batteries being charged, one of the online batteries satisfies a predetermined target voltage, the online battery has reached the predetermined target voltage again; and A battery control method, comprising the step of transmitting a switch control signal to a battery management device connected to the online battery to disconnect the connection of the online battery to the DC bus when the online battery has re-reached a predetermined target voltage.

18. In claim 17, The steps to switch to the above offline state are: When the online battery first reaches a predetermined target voltage, a step of transmitting a charge speed control signal to a battery management device connected to the online battery to lower the charge speed of the online battery; and A battery control method, comprising a step of transmitting a recalibration signal to the battery management device connected to the online battery to readjust the charging state of the online battery.

19. In claim 14, The steps to switch to the above offline state are: A step of checking whether any one of the plurality of online batteries being charged satisfies a predetermined target voltage; When the online battery satisfies a predetermined target voltage, a step of transmitting a charging speed control signal to a battery management device connected to the online battery to lower the charging speed of the online battery; A step of transmitting a recalibration signal to the battery management device connected to the online battery to readjust the charging state of the online battery; and A battery control method, comprising a step of transmitting a switch control signal to a battery management device connected to the online battery when the online battery is fully charged, thereby cutting off the connection of the online battery to the DC bus.

20. In claim 14, The steps to switch to the above offline state are: A battery control method performed until all of the above-mentioned multiple online batteries are switched to an offline state.

21. In claim 14, A battery control method further comprising a step of switching at least one offline battery to an online state during a discharge process of the battery system.

22. In claim 21, The steps to switch to the above online status are: A battery control method, comprising a step of switching at least one offline battery, for which cell balancing has been completed, to an online state.

23. In claim 21, The steps to switch to the above online status are: When the above battery system is in discharge mode, a step of switching the target offline battery to an online state; and A battery control method comprising a step of sequentially switching a plurality of offline batteries, excluding the target offline battery, to an online state.

24. In claim 23, The above target offline battery is, A battery control method, wherein the battery is the last one among the above multiple online batteries to be switched to an offline state.

25. In claim 23, The step of sequentially switching the above-mentioned multiple offline batteries to an online state is as follows: A step of monitoring the voltage of at least one of the above offline batteries; A step of obtaining a reference voltage of at least one of the above online batteries; A battery control method comprising: a step of comparing a difference between a reference voltage of the online battery and a voltage of the offline battery; and a step of switching at least one of the offline batteries, when the difference falls within a predefined voltage range, to an online state.

26. In claim 21, The steps to switch to the above online status are: A battery control method performed until all of the above-mentioned multiple offline batteries are switched to an online state.

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