Battery management device for a battery having a voltage plateau and its operating method

Abstract

A battery management device according to an embodiment of the present invention is a battery management device for managing and controlling a battery configured to be connected in parallel with other batteries, and may include at least one processor; and a memory for storing at least one instruction executed by the at least one processor; Here, the at least one instruction may include an instruction for diagnosing whether or not the battery is abnormal based on state information of the battery; and an instruction for controlling whether or not to release the parallel connection between the battery and other batteries based on whether or not the SOC (State of Charge) of the battery is within a threshold SOC range predefined as a SOC estimation impossible zone when the battery is determined to be in an abnormal state.

Description

[Technical Field]

[0001] This application claims the benefit of the filing dates of Korean Patent Application No. 10-2022-0122260 filed with the Korean Intellectual Property Office on September 27, 2022, and Korean Patent Application No. 10-2023-0006698 filed with the Korean Intellectual Property Office on January 17, 2023, and all of the contents disclosed in the documents of said Korean patent applications 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 and a control method thereof for stable operation of a battery system including a battery having a voltage plateau section. [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 ESS (Energy Storage Systems).

[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 curve between open-circuit voltage and SOC), making it difficult to accurately estimate the State of Charge (SOC) during this plateau.

[0007] During operation of a battery system in which battery assemblies are connected in parallel, if an abnormal condition occurs in a specific battery assembly, the battery assembly can be disconnected from the battery system (disconnected from the parallel connection), and can be reconnected to the battery system once the abnormal condition is resolved. Here, the battery assembly can be reconnected to the battery system if its SOC is the same as or very similar to the SOC of the other battery assemblies.

[0008] However, in the case of a battery system using LFP batteries, if an abnormal state occurs in a specific battery assembly during the voltage plateau period, the battery assembly must be fully charged or fully discharged in order to be reconnected after being disconnected from the battery system. This is because the SOC of an LFP battery cannot be accurately estimated during the voltage plateau period. As a result, it takes a considerable amount of time for the battery assembly to be reconnected to the battery system. Summary of the Invention [Problem to be solved by the invention]

[0009] SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to provide a battery management device for stable operation of a battery system including a battery having a voltage plateau section.

[0010] Another object of the present invention to solve the above problems is to provide a method for controlling such a battery management device.

[0011] 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]

[0012] To achieve the above object, a battery management device according to one embodiment of the present invention is a battery management device that manages and controls a battery that is connected in parallel with other batteries, and may include at least one processor; and a memory that stores at least one instruction to be executed through the at least one processor.

[0013] Here, the at least one command may include a command to diagnose whether or not there is an abnormality in the battery based on the state information of the battery; and, if the battery is determined to be in an abnormal state, a command to control whether or not to disconnect the parallel connection between the battery and another battery based on whether or not the SOC (State of Charge) of the battery is within a threshold SOC range predefined as an SOC estimation impossible zone.

[0014] Here, the threshold SOC range may be predefined as an SOC section in which the change in voltage relative to the change in SOC in the curve between the SOC and voltage of the battery is equal to or less than a predefined threshold.

[0015] The command to control whether to release the parallel connection may include a command to release the parallel connection between the battery and another battery when the SOC of the battery is outside the threshold SOC range.

[0016] The command for controlling whether to terminate the parallel connection may include a command for controlling whether to terminate the parallel connection between the battery and another battery depending on whether a predefined parallel connection maintenance condition based on the state information of the battery is satisfied when the SOC of the battery is within the threshold SOC range.

[0017] The instruction to control whether to release the parallel connection may include an instruction to maintain the parallel connection between the battery and another battery when a first condition defined as a state in which the amount of change in the cumulative current value of the battery is equal to or less than a predefined threshold is satisfied.

[0018] The instruction for controlling whether to terminate the parallel connection may include an instruction to maintain the parallel connection between the battery and another battery when a second condition is satisfied, the second condition being defined as a state in which a state value including at least one of a temperature value, a current value, and a voltage value of the battery is equal to or less than a predefined threshold value, or a state in which an amount of change in the state value is equal to or less than a predefined threshold value.

[0019] The command to control whether to release the parallel connection may include a command to release the parallel connection between the battery and another battery if the parallel connection maintenance condition is not satisfied.

[0020] To achieve the above-mentioned other object, a control method according to one embodiment of the present invention is a control method for a battery management device that manages and controls a battery that is configured to be connected in parallel with other batteries, and includes the steps of diagnosing whether or not there is an abnormality in the battery based on status information of the battery; and, if the battery is determined to be in an abnormal state, controlling whether or not to release the parallel connection between the battery and the other batteries based on whether or not the SOC (State of Charge) of the battery is within a threshold SOC range that is predefined as an SOC estimation impossible zone.

[0021] The threshold SOC range may be predefined as an SOC section in which the change in voltage relative to the change in SOC is equal to or less than a predefined threshold in a curve of the battery's SOC versus voltage.

[0022] The step of controlling whether to release the parallel connection may include the step of releasing the parallel connection between the battery and another battery when the SOC of the battery is outside the threshold SOC range.

[0023] The step of controlling whether to release the parallel connection may include a step of controlling whether to release the parallel connection between the battery and another battery depending on whether a predefined parallel connection maintenance condition is satisfied based on state information of the battery when the SOC of the battery is within the threshold SOC range.

[0024] The step of controlling whether to release the parallel connection may include a step of maintaining the parallel connection between the battery and another battery when a first condition defined as a state in which the amount of change in the cumulative current value of the battery is equal to or less than a predefined threshold is satisfied.

[0025] The step of controlling whether to release the parallel connection may include a step of maintaining the parallel connection between the battery and another battery when a second condition is satisfied, the second condition being defined as a state in which a state value including at least one of a temperature value, a current value, and a voltage value of the battery is equal to or less than a predefined threshold value, or a state in which an amount of change in the state value is equal to or less than a predefined threshold value.

[0026] The step of controlling whether to release the parallel connection may include the step of releasing the parallel connection between the battery and another battery if the parallel connection maintenance condition is not satisfied.

[0027] According to another embodiment of the present invention, a battery system may include a plurality of batteries connected in parallel; and a plurality of battery management devices provided corresponding to the plurality of batteries, respectively, for managing and controlling the corresponding batteries. Here, the battery management devices may diagnose whether or not a battery is abnormal based on battery status information, and if a battery is determined to be in an abnormal state, may control whether or not to terminate the parallel connection between the battery and other batteries based on whether or not the SOC (State of Charge) of the battery is within a threshold SOC range predefined as an SOC estimation impossible zone.

[0028] The threshold SOC range may be predefined as an SOC section in which the change in voltage relative to the change in SOC is equal to or less than a predefined threshold in a curve of the battery's SOC versus voltage.

[0029] The battery management device can disconnect the parallel connection between the battery and other batteries when the SOC of the battery is outside the threshold SOC range.

[0030] When the SOC of the battery is within the threshold SOC range, the battery management device can control whether to release the parallel connection between the battery and another battery depending on whether a predefined parallel connection maintenance condition is satisfied based on the state information of the battery.

[0031] The battery management device can maintain the parallel connection between the battery and other batteries when a first condition is satisfied, which is defined as a state in which the amount of change in the cumulative current value of the battery is less than or equal to a predefined threshold.

[0032] The battery management device can maintain the parallel connection between the battery and another battery when a second condition is satisfied, which is defined as a state in which a state value including at least one of a temperature value, a current value, and a voltage value of the battery is equal to or less than a predefined threshold value, or a state in which an amount of change in the state value is equal to or less than a predefined threshold value.

[0033] The battery management device can release the parallel connection between the battery and other batteries when the parallel connection maintaining condition is not satisfied. [Effects of the Invention]

[0034] According to the above-described embodiment of the present invention, abnormal battery shutdown during a voltage plateau period can be minimized, thereby improving the operational stability of the battery system. [Brief explanation of the drawings]

[0035] [Figure 1] FIG. 1 is a block diagram of a typical energy storage system. [Figure 2] The charging characteristic curve of an LFP battery is shown. [Figure 3] 1 is a block diagram of a battery system according to an embodiment of the present invention. [Figure 4] FIG. 3 is a flowchart of a control method for a battery management device according to an embodiment of the present invention. [Figure 5] FIG. 10 is a flowchart of a control method for a battery management device according to another embodiment of the present invention. [Figure 6] 1 is a block diagram of a battery management device according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which this invention pertains. Terms as defined in commonly used dictionaries should be interpreted as having 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.

[0041] Some terms used in this specification are defined as follows:

[0042] A battery cell is the smallest unit that serves to store power, and a battery module refers to an assembly of multiple battery cells that are electrically connected together.

[0043] A battery rack refers to a system with the smallest single structure that can be monitored and controlled through a Battery Management System (BMS) by connecting modules set by the battery manufacturer in series / parallel, and can be composed of multiple battery modules and one battery protection unit or any other protection device.

[0044] 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 for a battery bank can monitor and control the rack BMS (RBMS) for each battery rack, and each rack BMS manages the battery rack.

[0045] 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.

[0046] A BSC (Battery System Controller) is a device that performs top-level control for a battery system having a battery bank or a battery system having a multiple bank-level structure.

[0047] SOC (State of Charge) is the current charged state of the battery expressed as a percentage, and SOH (State of Health) is the current state of the battery compared to its ideal or original state expressed as a percentage.

[0048] FIG. 1 is a block diagram of a typical energy storage system.

[0049] 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 packs can form a battery rack. That is, a battery rack is a series / parallel combination of battery packs and can be the smallest unit of a battery system. Here, a battery pack can also be called a battery module depending on the device or system in which the battery is used.

[0050] Referring to FIG. 1, one battery rack 10 can include multiple battery modules and one battery protection unit (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's State of Charge (SOC) based on the monitoring results, and controls charging and discharging.

[0051] Meanwhile, 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), fuse, circuit breaker (CB), or disconnect switch (DS). The BPU can control the battery system in each rack by controlling the on / off of the main contactor through the control of the RBMS. The BPU can also protect the battery from short-circuit current using a fuse when a short circuit occurs. As such, conventional battery systems can be controlled through protection devices such as a BPU and switchgear.

[0052] Meanwhile, a BSC 20 is provided 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, which includes a bank-based battery system including multiple battery racks, and can also be used as a control device in a battery system with a multiple-bank structure.

[0053] In addition, a power conversion system (PCS) 40 provided for each battery section is a device that actually charges and discharges based on a charge / discharge command from the EMS 30, and may include a power conversion unit (DC / AC inverter) and a controller. Meanwhile, the output of each BPU may be connected to 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.

[0054] Figure 2 shows the charging characteristic curve of an LFP battery.

[0055] 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.

[0056] During the operation of the battery system, the battery management device can perform battery balancing control based on the SOC of the batteries or reconnect a battery that has been disconnected from the battery system to the battery system. To calculate the SOC of a battery, a method is commonly used in which the open-circuit voltage of the battery is measured and the SOC of the battery is estimated based on the measured open-circuit voltage.

[0057] 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). In other words, a battery system using an LFP battery can accurately estimate the SOC only in a very limited SOC range.

[0058] 1, if an abnormal condition occurs in a specific battery rack among the multiple battery racks 10 included in the battery system, the corresponding battery rack can be disconnected from the battery system by being disconnected from the parallel connection with the other battery racks. If the abnormal condition is subsequently resolved through inspection of the corresponding battery rack, the corresponding battery rack can be reconnected to the battery system. Here, for stable operation of the battery system, the corresponding battery rack needs to be reconnected to the battery system when the SOC of the corresponding battery rack is very similar to that of the other battery racks.

[0059] However, in the case of a battery rack equipped with LFP batteries, accurate SOC estimation is only possible in uneven sections (e.g., sections where the SOC is 90% or more or 10% or less), so the battery rack needs to be fully charged or fully discharged. Therefore, it takes a considerable amount of time for a disconnected battery rack to be reconnected to the battery system.

[0060] The present invention has been devised to solve the problems of the prior art, and relates to a battery management device and a control method thereof that can improve the operational stability of a battery system by minimizing abnormal battery shutdown measures in sections where accurate SOC estimation is not possible.

[0061] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0062] FIG. 3 is a block diagram of a battery system according to an embodiment of the present invention.

[0063] 3, a battery system according to an embodiment of the present invention may include a plurality of batteries 100 and a plurality of battery management devices 200 provided corresponding to each of the plurality of batteries and managing and controlling the corresponding battery. Here, the plurality of batteries 100 may be electrically connected in parallel to each other.

[0064] 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.

[0065] In an embodiment, the battery 100 may correspond to a battery assembly including one or more battery cells (e.g., LFP battery cells) having at least a voltage plateau section in a charging characteristic curve.

[0066] The BMS 200 can collect status information about the corresponding battery 100 and perform predefined control operations based on the collected status information to manage and control the corresponding battery 100. Here, the BMS 200 can control the charging and discharging of the battery and diagnose whether or not there is a failure in the battery cell based on the battery status information.

[0067] The battery management unit 200 controls the switching devices provided on the input / output side of the battery 100 to disconnect or reconnect the parallel connection with other batteries.

[0068] Each of the plurality of battery management devices 200 may be connected to a higher-level battery management device 300 via a network, configured to transmit battery status information to the higher-level battery management device 300, and to receive and operate control commands from the higher-level battery management device 300. Here, the higher-level battery management device 300 may correspond to a battery system controller (BSC), an energy management system (EMS), or a power management system (PMS).

[0069] Each battery management unit 200 can diagnose whether or not there is an abnormality in each battery based on the state information of the corresponding battery. For example, the battery management unit 200 can detect the occurrence of a fault such as a short circuit or a fire based on state information including one or more of the voltage value, current value, and temperature value of the battery.

[0070] When an abnormal state occurs in a specific battery, the battery management unit 200 corresponding to the abnormal battery can determine whether the SOC of the corresponding battery is within a threshold SOC range that is predefined as an SOC estimation impossible zone. Here, the battery management unit 200 can determine the current SOC of the corresponding battery by checking the voltage value of the corresponding battery when detecting the abnormal state of the battery, and checking the SOC corresponding to the checked voltage value through a pre-stored voltage-SOC relationship table.

[0071] The threshold SOC range may be predefined as an SOC interval in which the change in voltage relative to the change in SOC in a curve between the SOC and voltage of a battery is equal to or less than a predefined threshold. For example, the threshold SOC range may be defined as 5 to 95 or 10 to 90.

[0072] Thereafter, the battery management unit 200 can control whether or not to release the parallel connection between the abnormal battery and the other batteries based on whether or not the SOC of the abnormal battery is within the threshold SOC range.

[0073] If the SOC of an abnormal battery is outside a predefined threshold SOC range, the battery management unit 200 can control the input / output switch of the abnormal battery to an open state to disconnect the parallel connection with other batteries. That is, if the abnormal battery is in a state where the SOC can be estimated, the battery management unit 200 can disconnect the abnormal battery from the battery system, and once the abnormal state of the abnormal battery is resolved, control the corresponding battery to be reconnected to the battery system based on the calculated SOC.

[0074] If the SOC of an abnormal battery is within a predefined threshold SOC range, the battery management unit 200 can maintain the parallel connection between the abnormal battery and other batteries. Here, the battery management unit 200 can release the parallel connection with other batteries after the abnormal battery falls outside the threshold SOC range. That is, if the abnormal battery is in a state where SOC estimation is not possible, the battery management unit 200 does not immediately disconnect the abnormal battery from the battery system, but can disconnect it from the battery system after the state is switched to a state where SOC estimation is possible. This can reduce the unnecessary time it takes for the abnormal battery to be reconnected to the battery system.

[0075] FIG. 4 is a flowchart of a control method for a battery management device according to an embodiment of the present invention.

[0076] 4 may be performed by a battery management device that manages and controls a battery that is connected in parallel with other batteries. Here, the battery management device may correspond to a battery management system (BMS) that directly manages the battery, or may correspond to a higher-level BMS (e.g., a battery system controller (BSC), an energy management system (EMS), or a power management system (PMS)) of the BMS.

[0077] The battery management device collects battery status information and diagnoses whether or not there is an abnormality in the battery based on the collected status information (S410). For example, the battery management device collects status information including one or more of a voltage value, a current value, and a temperature value of the battery, and determines whether or not there is an abnormality such as a short circuit or a fire based on the collected status information.

[0078] If an abnormal state occurs in the battery (Y in S420), the battery management unit can determine whether the SOC of the battery is within a threshold SOC range defined in advance as an SOC estimation impossible zone (S430). Here, the battery management unit can control whether to release the parallel connection depending on whether the SOC of the battery is within the threshold SOC range.

[0079] The threshold SOC range can be predefined as an SOC interval in which the change in voltage relative to the change in SOC in the curve of the battery's SOC versus voltage is below a predefined threshold, and can be defined as, for example, 5 to 95, or 10 to 90.

[0080] If the SOC of the battery is outside the range of the predefined threshold SOC (N in S430), the battery management unit controls the input / output switch of the battery to the open state to disconnect the parallel connection with other batteries (S440). In other words, if the battery in which the abnormal state occurred is in a state where SOC estimation is possible, the battery management unit can disconnect the battery from the battery system.

[0081] If the SOC of the battery is within the predefined threshold SOC range (Y in S430), the battery management unit can maintain the parallel connection with other batteries (S450).

[0082] Thereafter, the battery management unit re-determines whether an abnormal state has occurred in the battery (S410, S420), and if the battery falls outside the threshold SOC range (N in S430), it can release the parallel connection with other batteries (S440).

[0083] Fig. 5 is a flow chart of a control method for a battery management device according to another embodiment of the present invention. The control method shown in Fig. 5 is an embodiment in which a step of determining whether a parallel connection is maintained is added to the control method shown in Fig. 4.

[0084] The battery management device collects battery status information and can diagnose whether or not there is an abnormality in the battery based on the collected status information (S510).

[0085] If an abnormal state occurs in the battery (Y in S520), the battery management device can determine whether the SOC of the battery is within a threshold SOC range that is predefined as an SOC estimation impossible section (S530).

[0086] If the SOC of the battery is outside the range of the predefined threshold SOC (N in S530), the battery management device can control the input / output switch of the battery to an open state to disconnect the parallel connection with other batteries (S540).

[0087] If the SOC of the battery is within a predefined threshold SOC range (Y in S530), the battery management device determines whether a predefined parallel connection maintenance condition is satisfied based on the battery state information (S550), and controls whether to terminate the parallel connection depending on the determination result. Here, if the parallel connection maintenance condition is not satisfied (N in S550), the battery management device can terminate the parallel connection with other batteries (S540), and if the parallel connection maintenance condition is satisfied (Y in S550), it can maintain the parallel connection with other batteries (S560).

[0088] The parallel connection maintaining condition may include a first condition defined as a state in which the amount of change in the cumulative current value of the battery is equal to or less than a predefined threshold value.

[0089] More specifically, when the abnormal battery is within the threshold SOC range (SOC estimation is not possible), the battery management device can check the accumulated current of the battery for a predetermined period of time. If the change in the accumulated current of the battery exceeds a predetermined threshold (first condition is not met), the parallel connection with the other batteries can be terminated, and if the change is equal to or less than the predetermined threshold (first condition is met), the parallel connection with the other batteries can be maintained.

[0090] In other words, even if the battery is in a state where SOC estimation is not possible (a state within the threshold SOC range) at the time of determining whether an abnormality has occurred, if the voltage subsequently fluctuates due to the accumulated current and the battery is switched to a state where SOC estimation is possible (the first condition is not satisfied), the parallel connection with other batteries can be terminated.

[0091] The parallel connection maintaining condition may include a second condition defined as a stable state of the battery. In one embodiment, the second condition may be defined as a state in which a state value including at least one of a temperature value, a current value, and a voltage value of the battery is equal to or less than a predefined threshold. In another embodiment, the second condition may be defined as a state in which a change in a state value including at least one of a temperature value, a current value, and a voltage value of the battery is equal to or less than a predefined threshold.

[0092] More specifically, when the abnormal battery is within the threshold SOC range (SOC estimation impossible state), the battery management device can monitor the battery state value for a predetermined period of time, and if the battery state value exceeds the predefined threshold (second condition not met), the parallel connection with other batteries can be terminated, and if the battery state value is equal to or less than the predefined threshold (second condition met), the parallel connection with other batteries can be maintained.

[0093] In other words, even if the battery is in a state where SOC estimation is not possible (a state within the threshold SOC range) at the time of abnormality determination, if the battery is in an unstable state (for example, a dangerous state where the temperature value exceeds the threshold value) (the second condition is not met), the parallel connection with other batteries can be disconnected.

[0094] In the embodiment, the battery management device may maintain the parallel connection with other batteries if both the first and second conditions included in the parallel connection maintenance conditions are satisfied, and may terminate the parallel connection with other batteries if either the first or second condition is not satisfied.

[0095] FIG. 6 is a block diagram of a battery management device according to an embodiment of the present invention.

[0096] The battery management device 600 according to an embodiment of the present invention may correspond to a device located in a battery system and managing and controlling a battery connected in parallel with other batteries. For example, the battery management device 600 may correspond to a rack battery management system (RBMS), a battery system controller (BSC), an energy management system (EMS), or a power management system (PMS), or may be embodied as being included in any one of them.

[0097] The battery management device 600 may include at least one processor 610, a memory 620 for storing at least one instruction executed by the processor, and a transceiver 630 for communicating with a network.

[0098] The at least one instruction may include an instruction to diagnose whether or not there is an abnormality in the battery based on the state information of the battery; and, if the battery is determined to be in an abnormal state, an instruction to control whether or not to disconnect the parallel connection between the battery and another battery based on whether or not the SOC (State of Charge) of the battery is within a threshold SOC range predefined as an SOC estimation impossible zone.

[0099] Here, the threshold SOC range may be predefined as an SOC section in which the amount of change in voltage relative to the amount of change in SOC is equal to or less than a predefined threshold in a curve corresponding to the SOC and voltage of the battery.

[0100] The command to control whether to release the parallel connection may include a command to release the parallel connection between the battery and another battery when the SOC of the battery is outside the threshold SOC range.

[0101] The command for controlling whether to terminate the parallel connection may include a command for controlling whether to terminate the parallel connection between the battery and another battery depending on whether a parallel connection maintenance condition predefined based on state information of the battery is satisfied when the SOC of the battery is within the threshold SOC range.

[0102] The instruction to control whether to release the parallel connection may include an instruction to maintain the parallel connection between the battery and another battery when a first condition defined as a state in which the amount of change in the cumulative current value of the battery is equal to or less than a predefined threshold is satisfied.

[0103] The instruction to control whether to release the parallel connection may include an instruction to maintain the parallel connection between the battery and another battery when a second condition is satisfied, the second condition being defined as a state in which a state value including at least one of a temperature value, a current value, and a voltage value of the battery is equal to or less than a predefined threshold, or a state in which an amount of change in the state value is equal to or less than a predefined threshold.

[0104] The command to control whether to release the parallel connection may include a command to release the parallel connection between the battery and another battery if the parallel connection maintenance condition is not satisfied.

[0105] The battery management device 600 may further include an input interface device 640, an output interface device 650, a storage device 660, etc. The components included in the battery management device 600 are connected to each other by a bus 670 to communicate with each other.

[0106] Here, the processor 610 may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which a method according to an 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).

[0107] 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.

[0108] 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.

[0109] 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 can be made to the present invention without departing from the spirit and scope of the present invention as set forth in the following claims. [Explanation of symbols]

[0110] 100:Battery 200:Battery management device 300: Upper battery management device 600:Battery management device

Claims

1. A battery management device that manages and controls a battery that is connected in parallel with one or more other 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: an instruction to control whether to release the parallel connection between the battery and the one or more other batteries based on whether the SOC (State of Charge) of the battery is within a threshold SOC range defined in advance as an SOC estimation impossible section; The instruction for controlling whether to release the parallel connection is and an instruction to control whether to release the parallel connection between the battery and the one or more other batteries depending on whether a parallel connection maintenance condition defined in advance based on state information of the battery is satisfied when the SOC of the battery is within the threshold SOC range. Battery management device.

2. The range of the threshold SOC is: A correlation curve showing the relationship between the SOC and voltage of the battery is predefined as an SOC section in which a change in voltage relative to a change in SOC is equal to or less than a predefined threshold. The battery management device according to claim 1 .

3. The instruction for controlling whether to release the parallel connection is and instructions for disconnecting a parallel connection between the battery and the one or more other batteries when the SOC of the battery is outside the threshold SOC range. The battery management device according to claim 1 .

4. The instruction for controlling whether to release the parallel connection is and an instruction to maintain a parallel connection between the battery and another battery when a first condition is satisfied, the first condition being defined as a state in which an amount of change in the cumulative current value of the battery is equal to or less than a predefined threshold. The battery management device according to claim 3 .

5. The instruction for controlling whether to release the parallel connection is and instructions to maintain a parallel connection between the battery and the one or more other batteries when a second condition is satisfied, the second condition being defined as a state in which a state value including at least one of a temperature value, a current value, and a voltage value of the battery is equal to or less than a predefined threshold value, or a state in which an amount of change in the state value is equal to or less than a predefined threshold value. The battery management device according to claim 3 .

6. The instruction for controlling whether to release the parallel connection is and an instruction to release the parallel connection between the battery and the one or more other batteries when the parallel connection maintenance condition is not satisfied. The battery management device according to claim 3 .

7. A control method for a battery management device that manages and controls a battery that is connected in parallel with one or more other batteries, controlling whether to release the parallel connection between the battery and the one or more other batteries based on whether the SOC (State of Charge) of the battery is within a threshold SOC range defined in advance as an SOC estimation impossible section; The step of controlling whether to release the parallel connection and when the SOC of the battery is within the threshold SOC range, controlling whether to release the parallel connection between the battery and the one or more other batteries depending on whether a parallel connection maintenance condition defined in advance based on state information of the battery is satisfied. A method for controlling a battery management device.

8. The range of the threshold SOC is: In a correspondence curve between the SOC and voltage of the battery, the SOC section is defined in advance as a section in which a change in voltage relative to a change in SOC is equal to or less than a predetermined threshold. A method for controlling a battery management device according to claim 7.

9. The step of controlling whether to release the parallel connection includes: If the SOC of the battery is outside the threshold SOC range, disconnecting the parallel connection between the battery and the one or more other batteries. A method for controlling a battery management device according to claim 7.

10. The step of controlling whether to release the parallel connection includes: maintaining a parallel connection between the battery and the one or more other batteries when a first condition is satisfied, the first condition being defined as a state in which a change in an accumulated current value of the battery is equal to or less than a predefined threshold; The method for controlling the battery management device according to claim 9.

11. The step of controlling whether to release the parallel connection includes: maintaining a parallel connection between the battery and the one or more other batteries when a second condition is satisfied, the second condition being defined as a state in which a state value including at least one of a temperature value, a current value, and a voltage value of the battery is equal to or less than a predefined threshold value, or a state in which an amount of change in the state value is equal to or less than a predefined threshold value; The method for controlling the battery management device according to claim 9.

12. The step of controlling whether to release the parallel connection includes: If the parallel connection maintaining condition is not satisfied, releasing the parallel connection between the battery and the one or more other batteries. The method for controlling the battery management device according to claim 9.

13. a plurality of batteries connected in parallel, the plurality of batteries comprising a first battery and one or more second batteries; and a plurality of battery management devices provided corresponding to the plurality of batteries, respectively, for managing and controlling the corresponding batteries; The battery management device controlling whether to release the parallel connection between the first battery and the one or more second batteries based on whether an SOC (State of Charge) of the first battery is within a threshold SOC range defined in advance as an SOC estimation impossible section; When the SOC of the first battery is within the threshold SOC range, controlling whether to release the parallel connection between the first battery and the one or more second batteries depending on whether a parallel connection maintenance condition predefined based on state information of the first battery is satisfied. Battery system.

14. The range of the threshold SOC is: The SOC section is defined in advance as a SOC section in which a change in voltage relative to a change in SOC is equal to or less than a predetermined threshold in a curve of the correspondence between the SOC and the voltage of the first battery. The battery system of claim 13.

15. The battery management device If the SOC of the first battery is outside the threshold SOC range, disconnecting the parallel connection between the first battery and the one or more second batteries. The battery system of claim 13.

16. The battery management device maintaining the parallel connection between the first battery and the one or more second batteries when a first condition is satisfied, the first condition being defined as a state in which a change in the accumulated current value of the first battery is equal to or less than a predefined threshold; The battery system of claim 15.

17. The battery management device maintaining the parallel connection between the first battery and the one or more second batteries when a second condition is satisfied, the second condition being defined as a state in which a state value including at least one of a temperature value, a current value, and a voltage value of the first battery is equal to or less than a predefined threshold value, or a state in which a change in the state value is equal to or less than a predefined threshold value; The battery system of claim 15.

18. The battery management device If the parallel connection maintaining condition is not satisfied, the parallel connection between the first battery and the one or more second batteries is released. The battery system of claim 15.

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