Battery management device for battery system that allows adding batteries and control method thereof

Abstract

A battery management device according to one embodiment of the present invention is a battery management device located in a battery system to which a new battery can be added, and may include at least one processor; and a memory for storing at least one instruction to be executed through the at least one processor. Here, the at least one command may include: an command to confirm a target SOC defined based on the SOH of the existing battery and the initial SOC of the new battery if the battery system is switched to a mode for adding a new battery; an command to control charging and discharging of the existing battery so that the existing battery has the target SOC; and an command to terminate charging and discharging control for the addition of the new battery if the existing battery reaches the target SOC.

Description

[Technical Field]

[0001] This application claims the benefit of the filing date of Korean Patent Application No. 10-2023-0024471, filed with the Korean Intellectual Property Office on February 23, 2022, and all of the contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a battery management device and a control method thereof, and more particularly to a battery management device located in a battery system to which a new battery can be added, and a control method thereof. [Background technology]

[0003] Secondary batteries are batteries that can be reused by recharging after discharge and can be used as energy sources for small devices such as mobile phones, tablet PCs, and vacuum cleaners, as well as medium- to large-sized devices such as automobiles and smart grid energy storage systems (ESS).

[0004] Secondary batteries are applied to systems in the form of assemblies such as battery modules in which a number of battery cells are connected in series and parallel, or battery packs in which battery modules are connected in series and parallel, depending on the requirements of the system.

[0005] Carbon materials are primarily used as the negative electrode active material for lithium secondary batteries, and lithium-containing cobalt oxide (LiCoO2) is primarily used as the positive electrode active material, although lithium-containing manganese oxide (LiMnO2, LiMn2O4, etc.) and lithium-containing nickel oxide (LiNiO2) are also being considered for use.

[0006] In recent years, lithium iron phosphate (LiFePO4)-based compounds have been used as the positive electrode active material in lithium secondary batteries. Lithium iron phosphate (LFP) batteries, which use lithium iron phosphate as the positive electrode active material, offer superior thermal stability and cost-effectiveness compared to other batteries. However, LFP batteries exhibit a flat characteristic with a voltage plateau in their charging characteristic curve (the relationship between open-circuit voltage and SOC), making it difficult to accurately estimate the State of Charge (SOC) during this plateau.

[0007] In order to resolve imbalances between batteries during the operation of a battery system, balancing control based on estimated SOC is essential. However, in the case of LFP batteries, it is difficult to accurately estimate the SOC in the flat section, so balancing control is only performed in non-flat sections (e.g., sections where the SOC is 90% or higher, or sections where the SOC is 10% or lower).

[0008] A new battery may be added or replaced in a battery system due to an increase in the capacity of the battery system or the failure of a specific battery. Generally, a new battery is connected when the existing battery has the shipping SOC of the new battery. During operation of the battery system after the new battery is connected, a difference in SOC between the existing battery and the new battery occurs due to a difference in SOH (State of Health) between the existing battery and the new battery. In particular, in a battery system using LFP batteries, the difference in SOC between the new battery and the existing battery becomes larger in the balancing control start section (e.g., the section where the SOC is 90% or more), which can lead to unnecessary repeated balancing control.

[0009] Therefore, there is a need for an appropriate control technology that can prevent unnecessary balancing control operations in a battery system that allows the addition of new batteries. Summary of the Invention [Problem to be solved by the invention]

[0010] SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to provide a battery management device that can prevent unnecessary balancing control operations in a battery system that allows the addition of new batteries.

[0011] Another object of the present invention to solve the above problems is to provide a method for controlling such a battery management device.

[0012] Another object of the present invention to solve the above problems is to provide a battery system including such a battery management device. [Means for solving the problem]

[0013] To achieve the above object, one embodiment of the present invention provides a battery system that allows the addition of one or more new batteries, and includes: an already installed battery; and a battery management device that monitors status information regarding the batteries included in the battery system and controls the batteries based on the status information.

[0014] Here, when the battery system is switched to a mode for adding a new battery, the battery management device checks a target SOC defined based on the SOH of the existing battery and the initial SOC of the new battery, controls charging and discharging so that the existing battery has the target SOC, and terminates the charging and discharging control when the target SOC is reached.

[0015] The target SOC may be defined as a value that allows the existing battery and the new battery to have the same SOC in an SOC section where balancing control is performed.

[0016] The target SOC can be calculated based on the SOH of the existing battery, the initial SOC of the new battery, and the balancing start SOC.

[0017] The target SOC can be calculated based on the following formula:

[0018] [Number 1] SOC_target=SOC_bal-K*(100 / SOH_old)

[0019] (SOC_target is the target SOC, SOC_bal is the balancing start SOC, SOH_old is the SOH of the existing battery, and K is the adjustment coefficient.)

[0020] Here, the adjustment coefficient K may be defined based on a difference between the balancing start SOC and the initial SOC of the new battery.

[0021] The new battery may be additionally installed in the battery system while the existing battery has the target SOC.

[0022] The battery management unit can start balancing control when one or more batteries reach a predefined balancing start SOC in a charge / discharge mode of the battery system.

[0023] In the battery system, the existing battery and the new battery may include one or more LFP battery cells.

[0024] In order to achieve the above-mentioned other object, a battery management device according to one embodiment of the present invention is a battery management device located in a battery system to which one or more new batteries can be added, and includes at least one processor; and a memory that stores at least one instruction to be executed through the at least one processor.

[0025] Here, the at least one command may include: a command to confirm a target SOC defined based on the SOH of the existing battery and the initial SOC of the new battery when the battery system is switched to a mode for adding a new battery; a command to control charging and discharging of the existing battery so that the existing battery has the target SOC; and a command to terminate charging and discharging control for adding the new battery when the existing battery reaches the target SOC.

[0026] The target SOC may be defined as a value that allows the existing battery and the new battery to have the same SOC in an SOC section where balancing control is performed.

[0027] The target SOC can be defined based on the SOH of the existing battery, the initial SOC of the new battery, and the balancing start SOC.

[0028] The target SOC can be calculated based on the following formula:

[0029] [Number 2] SOC_target=SOC_bal-K*(100 / SOH_old)

[0030] (SOC_target is the target SOC, SOC_bal is the balancing start SOC, SOH_old is the SOH of the existing battery, and K is the adjustment coefficient.)

[0031] Here, the adjustment coefficient K can be defined based on the difference between the balancing start SOC and the initial SOC of a new battery.

[0032] The at least one instruction may include an instruction to monitor the SOC of the new battery and the existing batteries when the battery system is switched to a charge / discharge mode; and an instruction to start balancing control when one or more batteries reach a predefined balancing start SOC.

[0033] To achieve the above-mentioned yet another object, a control method according to one embodiment of the present invention is a control method for a battery management device located in a battery system capable of adding one or more new batteries, and includes the steps of: when the battery system is switched to a mode for adding a new battery, confirming a target SOC defined based on the SOH of an existing battery and the initial SOC of the new battery; controlling the charging and discharging of the existing battery so that the existing battery has the target SOC; and, when the existing battery reaches the target SOC, terminating the charging and discharging control for the addition of the new battery.

[0034] The target SOC may be defined as a value that allows the existing battery and the new battery to have the same SOC in an SOC section where balancing control is performed.

[0035] The target SOC can be defined based on the SOH of the existing battery, the initial SOC of the new battery, and the balancing start SOC.

[0036] The target SOC can be calculated based on the following formula:

[0037] [Number 3] SOC_target=SOC_bal-K*(100 / SOH_old)

[0038] (SOC_target is the target SOC, SOC_bal is the balancing start SOC, SOH_old is the SOH of the existing battery, and K is the adjustment coefficient.)

[0039] Here, the adjustment coefficient K can be defined based on the difference between the balancing start SOC and the initial SOC of a new battery.

[0040] The control method of the battery management device may include the steps of: when the battery system is switched to a charge / discharge mode, monitoring the SOC of the new battery and the existing batteries; and, if one or more batteries reach a predefined balancing start SOC, starting balancing control. [Effects of the Invention]

[0041] According to the above-described embodiment of the present invention, it is possible to prevent unnecessary balancing control operations in a battery system in which a new battery can be added. [Brief explanation of the drawings]

[0042] [Figure 1] FIG. 1 is a block diagram of a typical energy storage system. [Figure 2] The charging characteristic curve of a lithium iron phosphate (LFP) battery is shown. [Figure 3] FIG. 1 is a reference diagram for explaining balancing logic of a general battery system. [Figure 4] 1 is a block diagram of a battery system according to an embodiment of the present invention. [Figure 5] FIG. 3 is an operational flow diagram of a control method for a battery management device according to an embodiment of the present invention. [Figure 6] FIG. 4 is a reference diagram for explaining a process for calculating a target SOC according to an embodiment of the present invention. [Figure 7] 10 is an operational flow diagram of a control method for a battery management device according to another embodiment of the present invention. [Figure 8] 1 is a block diagram of a battery management device according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0043] Since the present invention can be modified in various ways and can have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, it is understood that this is not intended to limit the present invention to the specific embodiments, but rather to include all modifications, equivalents, and alternatives within the spirit and technical scope of the present invention. Like reference numerals are used to refer to like elements throughout the drawings.

[0044] Terms such as "first," "second," "A," and "B" may be used to describe various components, but the components should not be limited by these terms. These terms are used only to distinguish one component from another. For example, a first component may be termed a "second component," and similarly, a second component may be termed a "first component," without departing from the scope of the present invention. The term "and / or" includes a combination of multiple associated listed items or any of multiple associated listed items.

[0045] When a component is referred to as being "coupled" or "connected" to another component, it is understood that the component may be directly coupled or connected to the other component, but that there may be other components in between. Conversely, when a component is referred to as being "directly coupled" or "directly connected" to another component, it is understood that there are no other components in between.

[0046] The terms used in this application are merely used to describe specific embodiments and are not intended to limit the present invention. The singular expressions include the plural expressions unless the context clearly indicates otherwise. It should be understood that in this application, the terms "comprise" or "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and do not preclude the presence or additional possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0047] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms as defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant art, and should not be interpreted as having an ideal or overly formal meaning unless expressly defined in this application.

[0048] Some terms used in this specification are defined as follows:

[0049] A battery cell is the smallest unit that serves to store power, and a battery module refers to an assembly of a plurality of battery cells that are electrically connected together.

[0050] A battery rack is a single-structure system that connects modules set by the battery manufacturer in series / parallel and can be monitored and controlled through a BMS (Battery Management System), and can be configured with multiple battery modules and one BPU or protection device.

[0051] A battery bank can refer to a large-scale collection of battery rack systems consisting of multiple racks connected in parallel. The battery bank BMS can monitor and control the rack BMS (RBMS) for each battery rack.

[0052] A battery assembly refers to an assembly including a plurality of electrically connected battery cells that is applied to a specific system or device and functions as a power supply source. Here, the battery assembly may refer to a battery module, a battery pack, a battery rack, a battery bank, or the like, but the scope of the present invention is not limited to these.

[0053] A BSC (Battery System Controller) is a device that performs top-level control of a battery system including a battery system in battery bank units, and can also be used as a control device in a battery system with a multi-bank level structure.

[0054] 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 [%].

[0055] FIG. 1 is a block diagram of a typical energy storage system.

[0056] The smallest unit of a battery that stores power in an energy storage system (ESS) is typically a battery cell. A series / parallel combination of battery cells forms a battery module, and a number of battery modules can form a battery rack. That is, a battery rack is a series / parallel combination of battery modules and can be the smallest unit of a battery system. Here, a battery module can also be called a battery pack depending on the device or system in which the battery is used.

[0057] Referring to FIG. 1, one battery rack 10 can include multiple battery modules and one BPU or protection device. The battery rack can be monitored and controlled through a rack BMS (RBMS). The RBMS monitors the current, voltage, and temperature of each battery rack under its control, calculates the battery SOC based on the monitoring results, and controls charging and discharging.

[0058] A Battery Protection Unit (BPU) is a device that protects batteries from abnormal current and fault current in each battery rack. The BPU can include a main contactor (MC), fuses, circuit breakers (CB), or disconnect switches (DS). The BPU can control the battery system in each rack by turning the main contactors on and off under the control of the RBMS. The BPU can also protect batteries from short-circuit current using fuses in the event of a short circuit. In this way, existing battery systems can be controlled through protection devices such as BPUs and switchgears.

[0059] Meanwhile, a BSC 20 is installed in each battery section, which includes a number of batteries and peripheral circuits and devices, and can monitor and control control targets such as voltage, current, temperature, and circuit breakers. The BSC is the highest-level control device in a battery system including a bank-unit battery system including a number of battery racks, and can also be used as a control device in a battery system with a multi-bank structure.

[0060] In addition, a power conversion system (PCS) 40 installed in each battery section is a device that actually charges and discharges based on a charge / discharge 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, 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.

[0061] Figure 2 shows the charging characteristic curve of a lithium iron phosphate (LFP) battery.

[0062] More specifically, Figure 2 shows the charging characteristic curve of an LFP (Lithium Iron Phosphate) battery, which uses lithium iron phosphate as the positive electrode active material. The charging characteristic curve shows the relationship between the open circuit voltage (OCV) measured during the charging process of the battery and the SOC.

[0063] During the operation of a battery system, a battery management system (BMS) can perform balancing control based on the battery's SOC. To calculate the battery's SOC, a common method is to measure the battery's open circuit voltage and estimate the battery's SOC based on the measured open circuit voltage.

[0064] Referring to Figure 2, the charging characteristic curve of an LFP battery has a voltage plateau in the SOC range of approximately 10% to approximately 90%. For an LFP battery with such a plateau characteristic, it is difficult to accurately estimate the SOC in the plateau range, and accurate estimation is possible only in the non-plateau range (e.g., the range where the SOC is 90% or more or the range where the SOC is 10% or less). Therefore, in a battery system using an LFP battery, balancing control is generally only performed in the non-plateau range.

[0065] FIG. 3 is a reference diagram for explaining the balancing logic of a general battery system.

[0066] In FIG. 1, if the capacity of the battery rack 10 needs to be increased or if a specific battery module included in the battery rack 10 needs to be replaced due to a failure, a new battery module can be added or the failed module can be replaced with a new battery module.

[0067] When a new battery module needs to be connected, the battery system is typically switched to a mode for adding a new battery (e.g., maintenance mode), and the charging and discharging process continues until the SOC of the existing battery module reaches the shipping SOC of the new battery module. For example, if the shipping SOC of the new battery module is 30%, the battery management device can control the charging and discharging of the existing battery module until the SOC of the existing battery module reaches 30%. Thereafter, when the existing battery module reaches the shipping SOC of the new battery module, the new battery module is electrically connected to the existing battery module.

[0068] After the new battery module is connected, when the battery system is switched to an operation mode (e.g., charge / discharge mode), both the new battery module and the existing battery modules are charged / discharged. At this time, the difference in SOH between the new battery module and the existing battery modules causes a difference in SOC between the batteries.

[0069] 3, when the SOC of an existing battery module is 30% (shipping SOC of a new battery module), if a new battery module is added to a battery system and the battery system is subsequently switched to a charge / discharge mode, a difference in SOC occurs between the new battery module and the existing battery module. This SOC difference occurs due to a difference in SOH between the batteries, and can increase as the charge / discharge period continues.

[0070] Meanwhile, in the case of a battery system using LFP batteries, balancing control is performed only in the non-flat section as described in Figure 2. However, if an already installed battery enters the balancing control start section (e.g., SOC 100%) first, a high imbalance state may be detected at this point, causing unnecessary repeated balancing control.

[0071] The present invention has been devised to solve these problems, and relates to a battery management device and a control method thereof that can prevent unnecessary balancing control operations in a battery system that allows the addition of new batteries.

[0072] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0073] FIG. 4 is a block diagram of a battery system according to an embodiment of the present invention.

[0074] Referring to FIG. 4A, a battery system according to an embodiment of the present invention may include pre-installed batteries (Bat #1 to Bat #N) 111 and a battery management device 120.

[0075] As shown in Fig. 4(B), the battery system according to the embodiment of the present invention may be configured by additionally installing a new battery (Bat #N+1) 112. Meanwhile, in the present invention, the new battery 112 refers to a battery that is additionally installed in addition to the existing batteries 111 or that replaces a specific battery (e.g., Bat #2) among the existing batteries 111 during operation of the battery system.

[0076] In the present invention, the batteries 111 and 112 may refer to battery modules, but the scope of the present invention is not limited to such objects. That is, the batteries 111 and 112 according to the present invention may refer to battery cells, battery racks, battery packs, or battery banks.

[0077] In an embodiment, the batteries 111 and 112 may correspond to battery cells (e.g., LFP battery cells) having at least a voltage plateau section in a charging characteristic curve, or may correspond to a battery assembly including one or more such battery cells.

[0078] In this embodiment, the existing batteries 111 may be configured to be connected in series with each other, and the new battery 112 may be configured to be connected in series with the existing batteries 111 when added to the battery system.

[0079] The battery management unit 120 monitors status information of the batteries 111 and 112 included in the battery system and can perform a predefined control operation based on the status information. For example, the battery management unit 120 can control the charging and discharging of the batteries based on the battery status information and can perform a predefined balancing control operation when an imbalance occurs between the batteries.

[0080] The battery management unit 120 may include sensors that collect status data of the batteries included in the battery system, or may be connected to such sensors via a network. For example, the battery management unit 120 may collect battery status data through a voltage sensor, a current sensor, and a temperature sensor.

[0081] The battery management unit 120 may calculate battery state information based on predefined state information calculation logic. For example, the battery management unit 120 may input specific state data (e.g., a voltage value, etc.) collected in real time into predefined SOC calculation logic to calculate the SOC of the battery. As another example, the battery management unit 120 may input specific state data (e.g., a voltage value, a current value, a cycle count, or an internal resistance value, etc.) into predefined SOH calculation logic to calculate the SOH of the battery.

[0082] When the battery system is switched to a mode for adding a new battery (e.g., maintenance mode), the battery management unit 120 can control the charging and discharging of the existing battery 111 so that the existing battery 111 has a predefined target SOC. Thereafter, when the SOC of the existing battery 111 reaches the target SOC, the battery management unit 120 can end the charging and discharging control and connect the new battery 112 to the existing battery 111.

[0083] FIG. 5 is a flowchart illustrating an operation of a control method for a battery management device according to an embodiment of the present invention.

[0084] When the battery system is switched to a mode for adding a new battery (for example, maintenance mode) (S510), the battery management device can check the target SOC of the already installed battery (S520).

[0085] The target SOC according to an embodiment of the present invention may be defined based on the SOH of the existing battery and the initial SOC of the new battery. Here, the target SOC may be defined as a value that allows the existing battery and the new battery to have the same SOC in an SOC section where balancing control is performed.

[0086] In an embodiment, the target SOC may be defined based on the SOH of the existing battery, the initial SOC of the new battery, and the balancing start SOC, where the target SOC may be calculated based on Equation 4 below.

[0087] [Number 4] SOC_target=SOC_bal-K*(100 / SOH_old)

[0088] where SOC_target is the target SOC, SOC_bal is the balancing start SOC, SOH_old is the SOH of the existing battery, and K is an adjustment coefficient defined based on the difference between the balancing start SOC and the initial SOC of the new battery. The target SOC will be described in detail later.

[0089] Thereafter, the battery management device can control the charging and discharging of the existing battery so that the existing battery has the target SOC (S530). Here, the battery management device can repeat the charging and discharging process by monitoring the SOC of the existing battery in real time, discharging the existing battery if the SOC of the existing battery is higher than the target SOC, and charging the existing battery if the SOC is lower than the target SOC (N in S540).

[0090] When the existing battery reaches the set target SOC (Y in S540), the battery management unit can terminate the charge / discharge control in order to add a new battery (S550).

[0091] When the charge / discharge operation in the mode for adding a new battery is completed, the existing battery has a target SOC (e.g., 12.5%), and in this state, the new battery (e.g., initial SOC 30%) can be electrically connected to the existing battery. Here, the target SOC is defined as a value that causes the existing battery and the new battery to have the same SOC in the SOC range (e.g., SOC 100%) where balancing control is performed. Therefore, if one or more batteries reach the balancing start SOC (e.g., SOC 100%) during the process of switching the battery system to the charge / discharge mode and operating, an imbalance due to SOH variations between the batteries does not occur, and unnecessary balancing control can be minimized.

[0092] Fig. 6 is a reference diagram for explaining the process of calculating the target SOC according to an embodiment of the present invention. Meanwhile, Fig. 6 shows the relationship between charging time and SOC when a new battery is connected to an existing battery and both are charged at a constant charge amount.

[0093] Referring to FIG. 6, the SOC of the battery can be calculated based on the following Equation 5.

[0094] [Number 5] SOC_t=SOC_0+(100 / SOH)*t

[0095] where SOC_t is the SOC at time t, and SOC_0 is the initial SOC.

[0096] That is, the amount of change in SOC per unit time is larger as the SOH is lower, and is smaller as the SOH is higher.

[0097] The SOC of the new battery and the existing battery can be calculated based on the following Equations 6 and 7.

[0098] [Number 6] SOC_new=SOC_new_int+(100 / SOH_new)*t

[0099] [Number 7] SOC_old=SOC_int_old+(100 / SOH_old)*t

[0100] Here, SOC_new_int is the initial SOC (or shipping SOC) of the new battery, SOC_int_old is the initial SOC of the already installed battery, SOH_new is the SOH of the new battery, and SOH_old is the SOH of the already installed battery.

[0101] The target SOC according to an embodiment of the present invention may be defined as a value at which the balancing control is initiated, such that the existing battery and the new battery have the same SOC. To calculate the target SOC, Equations 6 and 7 may be modified as follows:

[0102] [Number 8] SOC_bal=SOC_new_int+(100 / SOH_new)*t

[0103] [Number 9] SOC_bal=SOC_target+(100 / SOH_old)*t

[0104] Here, SOC_target is the target SOC of the installed battery, and SOC_bal is the balancing start SOC.

[0105] By rearranging the above Equations 8 and 9, the target SOC can be calculated as follows:

[0106] [Number 10] SOC_target=SOC_bal-K*(100 / SOH_old)

[0107] [Number 11] K=(SOC_bal-SOC_new_int)*(SOH_new / 100)

[0108] For example, if the balancing start SOC (SOC_bal) is set to 100%, the SOH of the existing battery (SOH_old) is 80%, the initial SOC of the new battery (SOC_new_int) is 30%, and the SOH of the new battery (SOH_new) is 100%, the target SOC can be calculated as 12.5% ​​(=100-70*(100 / 80)).

[0109] As another example, if the balancing start SOC (SOC_bal) is set to 90%, the SOH of the existing battery (SOH_old) is 80%, the initial SOC of the new battery (SOC_new_int) is 30%, and the SOH of the new battery (SOH_new) is 100%, the target SOC can be calculated as 15% (=90-60*(100 / 80)).

[0110] On the other hand, if the target SOC calculated based on the above formula has a value of 0 or less, the target SOC of the existing battery can be defined as a specific value of 0 or more and 5 or less.

[0111] When a new battery is installed while the existing battery has the target SOC according to the present invention, the existing battery will not reach the balancing start SOC first due to its low SOH (see FIG. 3). As a result, an imbalance due to SOH variations between batteries does not occur, and unnecessary balancing control can be minimized.

[0112] FIG. 7 is a flowchart showing an operation of a control method for a battery management device according to another embodiment of the present invention.

[0113] After completing the operation in the mode for adding a new battery (FIG. 5), when the installation of the new battery is completed (S710), the battery system can be switched to the charge / discharge mode (S720).

[0114] In the charge / discharge mode, the battery management device can monitor the status information of the batteries (new batteries and existing batteries) included in the battery system (S730).

[0115] The battery management unit may determine whether a defined balancing start condition is met based on the state information about the batteries (S740). Here, the balancing start condition may be defined as a state in which one or more batteries reach a predetermined balancing start SOC (e.g., SOC 100%).

[0116] If the balancing start condition is met (Y in S740), the battery management unit can operate in a balancing mode to perform a predefined balancing control operation (S750).

[0117] When the balancing mode is initiated, the battery management unit may determine whether a predefined imbalance condition is met based on battery status information (e.g., voltage or SOC) to determine whether balancing is necessary. For example, the imbalance condition may be defined as a state in which the difference between the minimum and maximum battery status values ​​(voltage or SOC) is equal to or greater than a predefined threshold. When the imbalance condition is met and it is determined that balancing is necessary, the battery management unit may perform a predefined balancing control operation. Here, the balancing control operation may include controlling a balancing circuit provided in the battery system to reduce the imbalance between the batteries. Meanwhile, known techniques such as passive and active balancing control methods may be applied to the balancing control method. Detailed descriptions of the balancing method and balancing circuit are not essential to the present invention, and therefore will not be provided here.

[0118] FIG. 8 is a block diagram of a battery management device according to an embodiment of the present invention.

[0119] The battery management device 800 according to an embodiment of the present invention may be located in a battery system to which a new battery can be added, and may correspond to a device that manages and controls the new battery and the existing battery. For example, the battery management device 800 may correspond to an RBMS, a BSC, an EMS, or a PMS, or may be embodied as being included in any one of them.

[0120] The battery management device 800 may include at least one processor 810, a memory 820 that stores at least one instruction executed by the processor, and a transceiver 830 that is connected to a network for communication.

[0121] The at least one instruction may include: an instruction to confirm a target SOC defined based on the SOH of the existing battery and the initial SOC of the new battery when the battery system is switched to a mode for adding a new battery; an instruction to control charging and discharging of the existing battery so that the existing battery has the target SOC; and an instruction to terminate charging and discharging control for adding the new battery when the existing battery reaches the target SOC.

[0122] The target SOC may be defined as a value that allows the existing battery and the new battery to have the same SOC in an SOC section where balancing control is performed.

[0123] The target SOC can be defined based on the SOH of the existing battery, the initial SOC of the new battery, and the balancing start SOC.

[0124] The target SOC can be calculated based on the following formula:

[0125] [Number 12] SOC_target=SOC_bal-K*(100 / SOH_old)

[0126] (SOC_target is the target SOC, SOC_bal is the balancing start SOC, SOH_old is the SOH of the existing battery, and K is the adjustment coefficient.)

[0127] Here, the adjustment coefficient K can be defined based on the difference between the balancing start SOC and the initial SOC of a new battery.

[0128] The at least one instruction may include an instruction to monitor the SOC of the new battery and the existing batteries when the battery system is switched to a charge / discharge mode; and an instruction to start balancing control when one or more batteries reach a predefined balancing start SOC.

[0129] The battery management device 800 may further include an input interface device 840, an output interface device 850, a storage device 860, etc. The components included in the battery management device 800 are connected to each other by a bus 870 to communicate with each other.

[0130] Here, the processor 810 may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which the method according to the embodiment of the present invention is performed. 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).

[0131] The operations of the methods according to the embodiments of the present invention can be embodied as a computer-readable program or code on a computer-readable recording medium. The computer-readable recording medium includes all kinds of storage devices in which data that can be read by a computer system is stored. In addition, the computer-readable recording medium can be distributed among computer systems connected via a network, so that the computer-readable program or code can be stored and executed in a distributed manner.

[0132] Some aspects of the invention have been described in the context of an apparatus, but they may also be described in terms of a corresponding method, where a block or apparatus corresponds to a method step or feature of a method step. Similarly, aspects described in the context of a method may be described in terms of a corresponding block or item or feature of a corresponding apparatus. Some or all of the method steps may be performed by (or using) a hardware apparatus, such as a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, one or more of the most important method steps may be performed by such an apparatus.

[0133] Although the present invention has been described above with reference to preferred embodiments, those skilled in the art will understand that various modifications and variations of the present invention can be made without departing from the spirit and scope of the present invention as set forth in the following claims. [Explanation of symbols]

[0134] 120, 800: Battery management device 111: Already installed battery 112: New battery

Claims

1. A battery system that allows the addition of one or more new batteries, Batteries already installed; and a battery management device that monitors status information related to a battery included in the battery system and controls the battery based on the status information; When the battery system is switched to a mode for adding a new battery, The battery management device confirming a target SOC defined based on the SOH of the existing battery and the initial SOC of the new battery, controlling charging and discharging so that the existing battery has the target SOC, and terminating the charging and discharging control when the target SOC is reached; Battery system.

2. The target SOC is It is defined as a value that makes the existing battery and the new battery have the same SOC in the SOC section where balancing control is performed. The battery system according to claim 1 .

3. The target SOC is Calculated based on the SOH of the existing battery, the initial SOC of the new battery, and the balancing start SOC. The battery system according to claim 1 .

4. The target SOC is It is calculated based on the following formula: The battery system according to claim 1 . SOC_target=SOC_bal-K*(100 / SOH_old) (SOC_target is the target SOC, SOC_bal is the balancing start SOC, SOH_old is the SOH of the existing battery, and K is an adjustment coefficient.)

5. The adjustment coefficient K is Defined based on a difference between the balancing start SOC and the initial SOC of the new battery. The battery system according to claim 4 .

6. The novel battery comprises: The battery is additionally installed in the battery system in a state where the already installed battery has the target SOC. The battery system according to claim 1 .

7. The battery management device When one or more batteries reach a balancing start SOC in a charge / discharge mode of the battery system, the balancing control is started. The battery system according to claim 6 .

8. the existing battery and the new battery include one or more LFP battery cells; The battery system according to claim 1 .

9. 1. A battery management device located in a battery system that allows for the addition of one or more new batteries, at least one processor; and a memory for storing at least one instruction to be executed by said at least one processor; The at least one instruction: instructions to confirm a target SOC defined based on the SOH of an existing battery and an initial SOC of the new battery when the battery system is switched to a mode for adding a new battery; An instruction to control charging and discharging of the already-installed battery so that the already-installed battery has the target SOC; and a command to terminate charge / discharge control for adding the new battery when the existing battery reaches the target SOC; Battery management device.

10. The target SOC is It is defined as a value that makes the existing battery and the new battery have the same SOC in the SOC section where balancing control is performed. The battery management device according to claim 9 .

11. The target SOC is Defined based on the SOH of the existing battery, the initial SOC of the new battery, and the balancing start SOC. The battery management device according to claim 9 .

12. The target SOC is It is calculated based on the following formula: The battery management device according to claim 9 . SOC_target=SOC_bal-K*(100 / SOH_old) (SOC_target is the target SOC, SOC_bal is the balancing start SOC, SOH_old is the SOH of the existing battery, and K is an adjustment coefficient.)

13. The adjustment coefficient K is Defined based on a difference between the balancing start SOC and the initial SOC of a new battery. The battery management device according to claim 12.

14. The at least one instruction: instructions for monitoring the SOC of the new battery and the existing battery when the battery system is switched to a charge / discharge mode; and instructions to initiate balancing control when one or more batteries reach a predefined balancing start SOC; The battery management device according to claim 9 .

15. 1. A method for controlling a battery management device located in a battery system that allows the addition of one or more new batteries, comprising: When the battery system is switched to a mode for adding a new battery, confirming a target SOC defined based on the SOH of the existing battery and the initial SOC of the new battery; Controlling charging and discharging of the already-installed battery so that the already-installed battery has the target SOC; and When the existing battery reaches the target SOC, terminating charge / discharge control to add the new battery. A method for controlling a battery management device.

16. The target SOC is It is defined as a value that makes the existing battery and the new battery have the same SOC in the SOC section where balancing control is performed. The method for controlling a battery management device according to claim 15.

17. The target SOC is Defined based on the SOH of the existing battery, the initial SOC of the new battery, and the balancing start SOC. The method for controlling a battery management device according to claim 15.

18. The target SOC is It is calculated based on the following formula: The method for controlling a battery management device according to claim 15. SOC_target=SOC_bal-K*(100 / SOH_old) (SOC_target is the target SOC, SOC_bal is the balancing start SOC, SOH_old is the SOH of the existing battery, and K is an adjustment coefficient.)

19. The adjustment coefficient K is Defined based on a difference between the balancing start SOC and the initial SOC of a new battery. The method for controlling a battery management device according to claim 18.

20. When the battery system is switched to a charge / discharge mode, monitoring the SOC of the new battery and the existing battery; and Initiating balancing control when one or more batteries reach a predefined balancing start SOC; The method for controlling a battery management device according to claim 15.

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