Battery management device and battery balancing method using the same

Abstract

A battery management device according to one embodiment of the present invention is a battery management device located in a battery system including a plurality of batteries, and may include at least one processor and a memory for storing at least one instruction executed through the at least one processor. Here, at least one of the above instructions may include an instruction to collect state information including the charge state value of the battery, an instruction to check whether one or more charge state values ​​of the battery belong to a predetermined low charge state interval or a high charge state interval, an instruction to determine whether the balancing start condition defined in correspondence with the current charge state interval is met based on the state information of the battery, and an instruction to determine whether or not to start a balancing mode for balancing the battery according to the determination result.

Description

Technical Field

[0001] This application claims the benefit of the filing date of Korean Patent Application No. 10-2023-018,8254, filed with the Korean Intellectual Property Office on December 21, 2023, and all of the contents disclosed in the document of the Korean Patent Application are incorporated herein.

[0002] The present invention relates to a battery system and a battery balancing method thereof, and more specifically, to a battery management device and a battery balancing method therefor for balancing batteries having a voltage plateau in a charging characteristic curve.

Background Art

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

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

[0005] As the negative electrode active material of a lithium secondary battery, a carbon material is mainly used, and as the positive electrode active material, mainly lithium-containing cobalt oxide (LiCoO2) is used. In addition, the use of lithium-containing manganese oxides (LiMnO2, LiMn2O4, etc.) and lithium-containing nickel oxides (LiNiO2) is also considered.

[0006] In recent years, lithium iron phosphate (LiFePO4) compounds have been used as the positive electrode active material for lithium secondary batteries. LFP (Lithium Iron Phosphate) batteries, which use lithium iron phosphate as the positive electrode active material, are superior to other batteries in terms of thermal stability and cost-effectiveness. However, LFP batteries exhibit a flat characteristic with a voltage flat section (plateau) in their charging characteristic curve (the curve relating open-circuit voltage and SOC), and there is a problem that the SOC (State of Charge) cannot be accurately estimated in the flat section.

[0007] Cell balancing control based on estimated State of Charge (SOC) is essential to resolve imbalances between battery cells during the operation of a battery system. However, in the case of LFP batteries, it is difficult to accurately estimate the SOC in flat sections, so cell balancing control is performed only in non-flat sections (for example, sections where the SOC is 90% or higher).

[0008] Therefore, appropriate control techniques are needed for balancing batteries such as LFP batteries, which have a voltage flat section in their charging characteristic curve. [Overview of the project] [Problems that the invention aims to solve]

[0009] The objective of the present invention, in order to solve the above-mentioned problems, is to provide a battery management device for balancing batteries having a voltage flat section in their charging characteristic curve.

[0010] Another object of the present invention, in order to solve the above-mentioned problems, is to provide a battery balancing method using such a battery management device.

[0011] Another objective of the present invention, in order to solve the problems described above, is to provide a battery system including such a battery management device. [Means for solving the problem]

[0012] A battery management device according to one embodiment of the present invention for achieving the above objective is a battery management device located in a battery system including a plurality of batteries, and may include at least one processor and a memory for storing at least one instruction executed through the at least one processor.

[0013] Here, at least one of the above instructions may include an instruction to collect state information including the charge state value of the battery, an instruction to check whether one or more charge state values ​​of the battery belong to a predetermined low charge state interval or a high charge state interval, an instruction to determine whether the balancing start condition defined in correspondence with the current charge state interval is met based on the state information of the battery, and an instruction to determine whether or not to start a balancing mode for balancing the battery according to the determination result.

[0014] The low-charge state interval described above is defined as an interval where the charge state value is less than or equal to a preset first charge state value, and the high-charge state interval described above may be defined as an interval where the charge state value is greater than or equal to a preset second charge state value.

[0015] The conditions for initiating balancing in the low-charge state range may include one or more of the following: a first condition in which the difference between the State of Health (SOH) of the battery is within a predetermined threshold range; a second condition in which the battery temperature is above a predetermined threshold temperature; and a third condition in which the battery's rest period exceeds a predetermined first period.

[0016] The balancing initiation conditions in the above-mentioned high-charge state section may include one or more of the following: a second condition in which the battery temperature is above a preset threshold temperature, and a fourth condition in which the battery's rest period exceeds a preset second period.

[0017] The above at least one instruction may further include an instruction to determine which battery to balance based on the difference between the charge state values ​​of the batteries once the balancing mode is started, and an instruction to execute a predefined balancing control on the battery to be balanced.

[0018] The command for determining the batteries to be balanced may include, when the balancing mode is started in the low-charge state section, a command to determine a battery with a charge state value whose difference from the minimum charge state value is equal to or greater than a preset first threshold, as the battery to be balanced, and when the balancing mode is started in the high-charge state section, a command to determine a battery with a charge state value whose difference from the minimum charge state value is equal to or greater than a preset second threshold, as the battery to be balanced.

[0019] Here, the first threshold value may be set to a value greater than the second threshold value.

[0020] The instruction to perform the balancing control described above may include an instruction to calculate the balancing period based on the capacity of the battery to be balanced, and an instruction to perform the balancing control during the balancing period.

[0021] The instruction to perform the balancing control described above may include an instruction to monitor whether one or more of the charge state values ​​of the batteries enter the high-charge state interval during the process of performing the balancing control.

[0022] The instruction to perform the balancing control described above may include an instruction to re-determine the battery to be balanced if one or more of the charge state values ​​of the batteries enter the high-charge state range and the balancing start condition in the high-charge state range is met.

[0023] The instruction for executing the above balancing control includes an instruction for monitoring whether one or more state-of-charge values of the above batteries decrease below a predefined third state-of-charge value during the process of executing the above balancing control, and an instruction for interrupting the above balancing control if the decrease is below the third state-of-charge value.

[0024] A battery balancing method according to an embodiment of the present invention for achieving the above another object is a battery balancing method by a battery management device for managing a plurality of batteries, including steps of collecting state information including the state-of-charge value of the above batteries, confirming whether one or more state-of-charge values of the above batteries belong to a predefined low state-of-charge range or high state-of-charge range, judging whether to meet a balancing start condition defined corresponding to the current state-of-charge range based on the state information of the above batteries, and determining whether to start a balancing mode for balancing the above batteries according to the judgment result.

[0025] The above low state-of-charge range may be defined as a range below a predefined first state-of-charge value, and the above high state-of-charge range may be defined as a range above a predefined second state-of-charge value.

[0026] The balancing start condition in the above low state-of-charge range may include one or more of the following: a first condition that the difference between the SOH (State of Health) of the above batteries is within a predefined threshold range, a second condition that the temperature of the above batteries is above a predefined threshold temperature, and a third condition that the rest period of the above batteries exceeds a predefined first period.

[0027] The balancing start condition in the above high state-of-charge range may include one or more of the following: a second condition that the temperature of the above batteries is above a predefined threshold temperature, and a fourth condition that the rest period of the above batteries exceeds a predefined second period.

[0028] If the above battery balancing method starts the above balancing mode, it may further include the steps of determining a battery to be balanced based on the difference between the state-of-charge values of the above batteries, and executing a predefined balancing control on the above battery to be balanced.

[0029] The step of determining the above battery to be balanced includes, when the balancing mode starts in the above low state-of-charge section, determining a battery having a state-of-charge value whose difference from the minimum state-of-charge value is greater than or equal to a preset first threshold as the above battery to be balanced, and, when the balancing mode starts in the above high state-of-charge section, determining a battery having a state-of-charge value whose difference from the minimum state-of-charge value is greater than or equal to a preset second threshold as the above battery to be balanced.

[0030] Here, the above first threshold may be set to a value greater than the above second threshold.

[0031] The step of executing the above balancing control may include the steps of calculating a balancing period based on the capacity of the above battery to be balanced, and executing the above balancing control during the above balancing period.

[0032] The step of executing the above balancing control may include the step of monitoring whether one or more state-of-charge values of the above batteries enter the above high state-of-charge section during the process of executing the above balancing control.

[0033] The step of executing the above balancing control may include the step of re-determining the above battery to be balanced if one or more state-of-charge values of the above batteries enter the above high state-of-charge section and meet the balancing start condition in the above high state-of-charge section.

[0034] The step of performing the balancing control described above may include the step of monitoring whether the charge state value of one or more of the batteries decreases to or below a predetermined third charge state value during the process of performing the balancing control, and the step of interrupting the balancing control if it decreases to or below the third charge state value.

[0035] A battery system according to one embodiment of the present invention for achieving the above-mentioned or other objectives may include a plurality of batteries and a battery management device that collects state information of the batteries and manages and controls the batteries based on the collected state information.

[0036] Here, the battery management device can check whether one or more of the battery's charge state values ​​belong to a predetermined low-charge state interval or high-charge state interval, determine whether the balancing start conditions defined in correspondence with the current charge state interval are met based on the battery's state information, and decide whether or not to start a balancing mode for balancing the battery according to the determination result. [Effects of the Invention]

[0037] According to the embodiments of the present invention described above, more balancing control can be performed on a battery having flat characteristics, the battery's charge state can be maintained more uniformly, and the capacity of the battery system can be utilized to the fullest extent. [Brief explanation of the drawing]

[0038] [Figure 1] The charging characteristic curve of the LFP battery is shown. [Figure 2] This is a block diagram illustrating the battery system according to the present invention. [Figure 3] This is an operational flowchart of a battery balancing method according to an embodiment of the present invention. [Figure 4] This is an operational flowchart of the battery balancing method after the start of the balancing mode according to an embodiment of the present invention. [Figure 5]This is an operational flowchart of a battery balancing method according to another embodiment of the present invention. [Figure 6] This is an operational flowchart of a battery balancing method according to another embodiment of the present invention. [Figure 7] This is a block diagram of a battery management device according to an embodiment of the present invention. [Modes for carrying out the invention]

[0039] The present invention can be modified in various ways and may have many different embodiments, but specific embodiments are illustrated in the drawings and described in detail in the detailed description. This is not intended to limit the present invention to specific embodiments, but should be understood to include all modifications, equivalents, or substitutes that fall within the spirit and technical scope of the present invention. Similar reference numerals are used for similar components in the description of each drawing.

[0040] Terms such as First, Second, A, B, etc., may be used to describe various components, but the components should not be limited by these terms. These terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the First component may be named the Second component, and similarly, the Second component may be named the First component. The term "and / or" includes a combination of multiple related items or one of multiple related items.

[0041] When it is stated that one component is "linked" or "connected" to another component, it should be understood that this may mean that it is directly linked or connected to that other component, but that there may also be another component in between. Conversely, when it is stated that one component is "directly linked" or "directly connected" to another component, it should be understood that there is no other component in between.

[0042] The terms used in this application are used solely to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless they are clearly different in context. In this application, terms such as “includes” or “having” are intended to specify the existence of features, figures, steps, actions, components, parts, or combinations thereof described in the specification, and should not be understood to preemptively exclude the existence or possibility of adding one or more other features, figures, steps, actions, components, parts, or combinations thereof.

[0043] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as those generally understood by a person of ordinary skill in the art to which this invention pertains. Terms as defined in commonly used dictionaries should be interpreted as having the meaning consistent with their meaning in the context of the relevant art, and not as ideal or overly formal unless explicitly defined herein.

[0044] Some terms used in this specification are defined as follows:

[0045] A battery cell is the smallest unit that stores electricity, while a battery module refers to an assembly of multiple battery cells that are electrically connected.

[0046] A battery rack refers to a single-structure system in which modules, as defined by the battery manufacturer, are connected in series or parallel and can be monitored and controlled through a Battery Management System (BMS). It may consist of multiple battery modules and one Battery Protection Unit (BPU) or protective device. Depending on the device or system in which the batteries are used, the battery modules may also be called a battery pack.

[0047] A battery bank can refer to a collection of large-scale battery rack systems, each consisting of multiple battery racks connected in parallel. Monitoring and control of the rack-based battery management systems (RBMS) at the battery rack level can be performed through a battery bank-level BMS.

[0048] A battery assembly refers to a collection comprising multiple electrically connected battery cells that is applied to a specific system or device to function as a power source. Here, a battery assembly can mean a battery module, battery pack, battery rack, or battery bank, but the scope of the present invention is not limited to these individuals.

[0049] SOC (State of Charge) represents the current charge level of a battery as a percentage [%], while SOH (State of Health) represents the current remaining charge level of a battery as a percentage [%].

[0050] Nominal Capacity (Nominal Capa.) can refer to the battery's initial capacity [Ah] set by the battery manufacturer during development.

[0051] Figure 1 shows the charging characteristic curve of the LFP battery.

[0052] More specifically, Figure 1 shows the charging characteristic curve of an LFP (Lithium Iron Phosphate) battery in which lithium iron phosphate oxide is used as the positive electrode active material. The charging characteristic curve shows the correspondence between the open circuit voltage (OCV) measured during the battery charging process and the state of charge (SOC).

[0053] To resolve imbalances between battery cells during the operation of a battery system, a battery management system can compare the State of Charge (SOC) of the battery cells to determine the state of imbalance. If the imbalance exceeds a predetermined threshold, balancing control can be performed. In this process, the most commonly used method for determining the state of imbalance between battery cells is to measure the open-circuit voltage of the battery and estimate the SOC of the battery based on the measured open-circuit voltage.

[0054] Referring to Figure 1, the charging characteristic curve of an LFP battery has a voltage plateau in the state of charge (SOC) range of approximately 10% to 90%. In the case of an LFP battery with such a plateau characteristic, it is difficult to accurately estimate the SOC in the plateau range, so balancing control needs to be performed in the non-flat range.

[0055] When performing balancing on LFP batteries in the low SOC range (for example, the range where the SOC is 10% or less), it is difficult to accurately select the unbalanced batteries (the batteries to be balanced), and the balancing control can cause a rapid decrease in battery voltage, potentially leading to over-discharge.

[0056] Therefore, in battery systems where LFP is applied, balancing control is generally performed in the SOC range (for example, the range where the SOC is 90% or higher). However, in the case of battery systems linked with PV (photovoltaic, solar power generation systems), it is often not possible to reach a fully charged state (high SOC range) due to weather conditions, resulting in a lower frequency of balancing control execution. This can lead to an unresolved imbalance between batteries and the potential for state variability.

[0057] The present invention was devised to solve these problems, and preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0058] Figure 2 is a block diagram illustrating the battery system according to the present invention.

[0059] Referring to Figure 2, the battery system may include a battery assembly 100 containing multiple batteries 10 and a battery management device 200.

[0060] Multiple batteries 10 may be electrically connected to each other to form a battery assembly.

[0061] Battery 10 can mean a battery cell, a battery module, or a battery rack.

[0062] The battery 10 may correspond to an LFP battery cell, or to a battery module or battery rack containing a plurality of LFP batteries. However, the scope of the present invention is not limited to these embodiments. That is, the battery according to the present invention may correspond to a battery having at least a portion of the voltage flat section in its charging characteristic curve, or to a battery module or battery rack containing such a battery.

[0063] The battery management device 200 can collect status information about multiple batteries 10 and manage and control the battery assembly 100 by executing predefined control operations based on the collected status information. Here, the battery management device 200 can control the charging and discharging of batteries, diagnose whether or not there are battery failures, determine the imbalance state of the batteries and perform balancing control.

[0064] The battery management device 200 may correspond to a BMS located inside the battery system, or may be implemented as part of the BMS.

[0065] The battery system according to the embodiment of the present invention may be implemented within an Energy Storage System (ESS), but the scope of the present invention is not limited to these embodiments. That is, the battery system according to the present invention may be applied to a variety of devices, such as electric vehicles.

[0066] Figure 3 is an operational flowchart of a battery balancing method according to an embodiment of the present invention.

[0067] The battery balancing method according to an embodiment of the present invention may be performed by a battery management device located within the battery system.

[0068] The battery management device can collect battery status information (S310). Here, the status information may include one or more of the following for each battery: charge status value, temperature, and SOH.

[0069] In the present invention, the charge state value means a value indicating the charge state of the battery, and may include one or more of the battery's state of charge (SOC), voltage value, and open-circuit voltage (OCV).

[0070] The battery management device can determine whether the battery system belongs to a predetermined charge state interval based on the charge state values ​​of the batteries (S320). Here, the battery management device can determine whether one or more charge state values ​​of the batteries belong to a predetermined low charge state interval or a high charge state interval.

[0071] A low-charge state interval may be defined as an interval where the charge level is below a preset first charge level value, and a high-charge state interval may be defined as an interval where the charge level is above a preset second charge level value. For example, a low-charge state interval may be defined as an interval where the SOC is 35% or less, and a high-charge state interval may be defined as an interval where the SOC is 95% or more.

[0072] In this embodiment, the battery management device can determine that the battery system belongs to a low-charge state range if the number of batteries with a charge state value less than or equal to a first charge state value is N or more, as set in advance. For example, if it is confirmed that the charge state value of all batteries is 35% or less, the battery management device can determine that the battery system belongs to a low-charge state range.

[0073] In this embodiment, the battery management device can determine that the battery system belongs to a high-charge state section if the number of batteries with a charge state value equal to or greater than a second charge state value is M or more, which is a preset value. For example, if it is confirmed that there is one or more batteries with a charge state value of 95% or higher, the battery management device can determine that the battery system belongs to a high-charge state section.

[0074] If the battery system is in a low-charge state section or a high-charge state section (Y in S320), the battery management device can determine whether or not the predefined balancing start conditions are met (S330). Here, the battery management device can confirm whether or not the balancing start conditions defined in correspondence with the current charge state section are met, based on the battery state information.

[0075] The conditions for initiating balancing in the low-charge state may include one or more of the following: a first condition in which the difference between the State of Health (SOH) of the battery is within a preset threshold range; a second condition in which the battery temperature is above a preset threshold temperature; and a third condition in which the battery's rest period exceeds a preset first period.

[0076] For example, the conditions for starting balancing in a low-charge state can include a first condition where the difference between the SOH of the batteries is within 3%, a second condition where the temperature of all batteries is 0 degrees Celsius or higher, and a third condition where the battery rest period exceeds 60 minutes. If the current charge state period confirmed in S320 is a low-charge state period, the battery management device can check whether the first, second, and third conditions are met based on the battery status information.

[0077] The balancing initiation conditions in the high-charge state section may include one or more of the following: a second condition in which the battery temperature is above a preset threshold temperature, and a fourth condition in which the battery rest period exceeds a preset second period. Here, the second period may be defined as a period shorter than the first period.

[0078] For example, the balancing initiation conditions in a high-charge state section may include a second condition that the temperature of all batteries is 0 degrees Celsius or higher, and a fourth condition that the battery rest period exceeds 10 minutes. If the current charge state section confirmed in S320 is a high-charge state section, the battery management device can check whether the second and fourth conditions are met based on the battery status information.

[0079] On the other hand, the balancing start conditions in the low-charge state section differ from those in the high-charge state section and may further include conditions related to the equilibrium of SOH (first condition). This allows balancing control to be performed in both the low-charge and high-charge states if there is little or no variation in SOH between batteries. Conversely, if there is a large variation in SOH between batteries (for example, if a particular battery is replaced), balancing control may not be performed in the low-charge state but only in the high-charge state. When there is a large variation in SOH between LFP batteries, it is difficult to accurately determine the charge state value of the batteries in the low-charge state section. According to the above embodiment, when there is a large variation in SOH between batteries, the problem of reduced accuracy in balancing control can be resolved by performing balancing control only in the high-charge state section.

[0080] The battery management device can decide whether or not to start a balancing mode for balancing the batteries, depending on the result of the determination in S330.

[0081] If it is determined that the current charging state interval and the corresponding balancing start conditions are met (Y in S330), the battery management device can start the balancing mode (S340).

[0082] If it is determined that the balancing start conditions are not met (N in S330), the battery management device may return to S310 without starting the balancing mode.

[0083] Figure 4 is an operation flowchart of the battery balancing method after the start of the balancing mode according to an embodiment of the present invention.

[0084] Once balancing mode is started (S410), the battery management device can determine one or more batteries to be balanced based on the difference in charge states between the batteries (S420).

[0085] Specifically, the battery management device can select batteries that meet predefined conditions based on the difference between the charge state values ​​of the batteries, and determine the selected batteries to be balanced. Here, the battery management device can determine batteries to be balanced if their charge state value is greater than or equal to a pre-set threshold value, compared to the minimum charge state value.

[0086] The conditions for selecting the batteries to be balanced may be defined in accordance with the current charge state interval.

[0087] When balancing mode is initiated in a low-charge state, the battery management device can determine batteries with a charge state value that is greater than or equal to a preset first threshold value from the minimum charge state value as batteries to be balanced. For example, the battery management device can determine batteries with an SOC value that is 5% or more greater than or equal to the minimum SOC value as batteries to be balanced.

[0088] When balancing mode is initiated in a high-charge state, the battery management device can determine batteries with a charge state value that is greater than or equal to a preset second threshold value from the minimum charge state value as batteries to be balanced. Here, the first threshold value may be set to a value greater than the second threshold value. For example, the battery management device can determine batteries with an SOC value that is greater than or equal to the minimum SOC value as batteries to be balanced.

[0089] By setting the second threshold to a value smaller than the first threshold, the frequency of balancing control can be increased in the high-charge state range, and misconfiguration of the battery to be balanced in the low-charge state can be minimized.

[0090] Once the batteries to be balanced are determined, the battery management device can calculate the balancing period (S430).

[0091] A battery management device can calculate the balancing period based on the capacity of the batteries to be balanced. Here, the battery management device can set a predetermined percentage of the capacity of the batteries to be balanced as the balancing limit, and calculate the balancing period based on the balancing limit and the balancing rate. For example, the battery management device can set 0.1% of the lowest capacity of each of the batteries to be balanced as the balancing limit, and calculate the balancing period based on the set balancing limit and the discharge rate (amount of discharge per unit time) by the balancing circuit.

[0092] The battery management device can perform predefined balancing control on the batteries to be balanced (S440).

[0093] A battery management device can perform balancing control by controlling the balancing circuit provided in the battery system to reduce imbalances between battery cells. For example, a battery management device can reduce variations in the charge state between batteries by controlling the passive balancing circuit included in the battery system and forcing the batteries to be balanced to discharge.

[0094] The battery management device can perform balancing control during the balancing period calculated in S430. Specifically, after the balancing control is started, the battery management device monitors whether the balancing period has been completed (S450), and if the balancing period is completed (Y in S450), it can terminate the balancing control (end of balancing mode) (S460).

[0095] During the process of balancing control being performed (N in S450), the battery management device can confirm whether the conditions for starting balancing in the high-charge state are met based on the battery status information (S470).

[0096] Specifically, the battery management device can monitor whether one or more of the battery charge states enter the high-charge state range during the balancing control process. If one or more of the battery charge states enter the high-charge state range and the conditions for starting balancing in the high-charge state range are met, the battery management device returns to S420 and can re-determine which batteries to balance.

[0097] After the balancing mode is started in a low-charge state, the battery system can be switched to a high-charge state by charging. Therefore, during the process of balancing control, the battery management device checks whether the high-charge state section has been entered and whether the balancing start conditions in the high-charge state section (for example, the second and fourth conditions) are met. If the conditions are met, the battery to be balanced can be updated and then the balancing control can be executed.

[0098] The battery management device can monitor whether the charge state value of one or more batteries decreases to or below a predetermined third charge state value during the balancing control process. If it does decrease to or below the third charge state value, the battery management device can interrupt the balancing control. For example, during the balancing control process, the battery management device can monitor the battery voltage values ​​and, if it confirms that the minimum voltage value has decreased to 2.7V or less, it can interrupt the balancing control.

[0099] After balancing control is interrupted, the battery management device can monitor whether the charge state value of one or more of the batteries increases to or above a predetermined fourth charge state value. If it does increase to or above the fourth charge state value, the battery management device can release the interruption of balancing control and resume balancing control. For example, if it is confirmed that the minimum voltage value has increased to or above 3.22V after balancing control has been interrupted, the battery management device can release the interruption of balancing control and resume balancing control.

[0100] Figures 5 and 6 are operational flowcharts of a battery balancing method according to another embodiment of the present invention. Specifically, Figures 5 and 6 are concrete examples of the battery balancing method shown in Figures 3 and 4.

[0101] First, referring to Figure 5, the battery management device can collect battery status information. Here, the status information may include the charge status value, temperature, and SOH for each battery.

[0102] The battery management device can check whether the battery temperature is above a preset threshold temperature (Td) (whether the second condition is met) (S510).

[0103] If the temperature of all batteries is above the threshold temperature (Td) (Y in S510), the battery management device can check whether the difference between the SOH of the batteries is within a preset threshold range (SOHd) ​​(whether the first condition is met) (S520).

[0104] If the difference between the SOH values ​​of the batteries is within a preset threshold range (SOHd) ​​(Y in S520), the battery management device can confirm whether the battery system currently belongs to the low-charge state section and whether the battery's idle period exceeds a preset first period (t1) (whether the third condition is met) (S531). If the battery belongs to the low-charge state section and the idle period exceeds the first period (Y in S531), the battery management device can determine which batteries to balance (S541). Specifically, the battery management device can determine which batteries to balance are those having a charge state value whose difference from the minimum charge state value is greater than or equal to a preset first threshold value.

[0105] If the battery does not belong to the low-charge state section, or if the rest period is less than or equal to the first period (N in S531), the battery management device can check whether the battery system currently belongs to the high-charge state section and whether the battery rest period exceeds a preset second period (t2) (whether the fourth condition is met) (S532). On the other hand, if the difference between the SOH of the batteries is outside a preset threshold range (SOHd) ​​(N in S520), the battery management device can execute S532. If the battery belongs to the high-charge state section and the rest period exceeds the second period (Y in S532), the battery management device can determine which batteries are to be balanced (S542). Specifically, the battery management device can determine which batteries are to be balanced if their charge state value is greater than or equal to a preset second threshold value. Here, the first threshold value may be set to a value greater than the second threshold value.

[0106] If there is one or more batteries to be balanced (Y in S541, Y in S542), the battery management device can set the balancing period (S550). Here, the battery management device sets a predetermined ratio to the capacity of the batteries to be balanced as the balancing limit, and can calculate the balancing period based on the balancing limit and the balancing speed.

[0107] The battery management device can initiate balancing control for the batteries to be balanced (S560). For example, the battery management device can reduce variations in the charge state between batteries by controlling the passive balancing circuit included in the battery system to forcibly discharge the batteries to be balanced.

[0108] Next, referring to Figure 6, once balancing control is started, the battery management device can monitor whether or not the balancing period has been completed (S610).

[0109] Once the balancing period is complete (Y in S610), the battery management device terminates the balancing control (end of balancing mode) (S620) and can initialize the parameters related to the balancing control (S630).

[0110] During the process of balancing control being performed (N in S610), the battery management device can confirm, based on the battery status information, whether or not the conditions for starting balancing in the high-charge state section are met (S640).

[0111] If the battery system enters a high-charge state and the conditions for starting balancing in the high-charge state are met (Y in S640), the battery management device can re-determine which battery to balance (S650).

[0112] If there is one or more batteries to be balanced (Y in S650), the battery management device can set the balancing period for the newly determined batteries to be balanced (S550) and then start balancing control (S560).

[0113] If the conditions for starting balancing in the high-charge state are not met (N in S640), the battery management device can check whether the minimum value of the battery voltage decreases to or below the set value (V1, the third charge state value) (S660). If it decreases to or below the set value (Y in S660), the battery management device can interrupt the balancing control (S670).

[0114] If the battery voltage has not decreased below the third charge state value (N in S660), the battery management device can check whether the minimum value of the battery voltage increases to or above the set value (V2, the fourth charge state value) (S680). If it increases to or above the set value, the battery management device can release the interruption of balancing control and restart balancing control (S690).

[0115] Figure 7 is a block diagram of a battery management device according to an embodiment of the present invention.

[0116] An embodiment of the present invention, the battery management device 700, is located within a battery system including multiple batteries and can manage and control the batteries.

[0117] The battery management device 700 may be a BMS located inside the battery system, or it may be implemented as part of the BMS.

[0118] The battery management device 700 may include at least one processor 710, a memory 720 for storing at least one instruction executed through the processor, and a transceiver 730 connected to a network for communication.

[0119] The above-mentioned at least one instruction may include an instruction to collect state information including the charge state value of the battery, an instruction to check whether one or more charge state values ​​of the battery belong to a predetermined low-charge state interval or a high-charge state interval, an instruction to determine whether the balancing start condition defined in correspondence with the current charge state interval is met based on the state information of the battery, and an instruction to determine whether or not to start a balancing mode for balancing the battery according to the determination result.

[0120] The low-charge state interval described above is defined as an interval where the charge state value is less than or equal to a preset first charge state value, and the high-charge state interval described above may be defined as an interval where the charge state value is greater than or equal to a preset second charge state value.

[0121] The conditions for initiating balancing in the low-charge state range may include one or more of the following: a first condition in which the difference between the State of Health (SOH) of the battery is within a predetermined threshold range; a second condition in which the battery temperature is above a predetermined threshold temperature; and a third condition in which the battery's rest period exceeds a predetermined first period.

[0122] The balancing initiation conditions in the above-mentioned high-charge state section may include one or more of the following: a second condition in which the battery temperature is above a preset threshold temperature, and a fourth condition in which the battery's rest period exceeds a preset second period.

[0123] The above at least one instruction may further include an instruction to determine which battery to balance based on the difference between the charge state values ​​of the batteries once the balancing mode is started, and an instruction to execute a predefined balancing control on the battery to be balanced.

[0124] The command for determining the batteries to be balanced may include, when the balancing mode is started in the low-charge state section, a command to determine a battery with a charge state value whose difference from the minimum charge state value is equal to or greater than a preset first threshold, as the battery to be balanced, and when the balancing mode is started in the high-charge state section, a command to determine a battery with a charge state value whose difference from the minimum charge state value is equal to or greater than a preset second threshold, as the battery to be balanced.

[0125] Here, the first threshold value may be set to a value greater than the second threshold value.

[0126] The instruction to perform the balancing control described above may include an instruction to calculate the balancing period based on the capacity of the battery to be balanced, and an instruction to perform the balancing control during the balancing period.

[0127] The instruction to perform the balancing control described above may include an instruction to monitor whether one or more of the charge state values ​​of the batteries enter the high-charge state interval during the process of performing the balancing control.

[0128] The instruction to perform the balancing control described above may include an instruction to re-determine the battery to be balanced if one or more of the charge state values ​​of the batteries enter the high-charge state range and the balancing start condition in the high-charge state range is met.

[0129] The instruction to perform the balancing control described above may include an instruction to monitor whether the charge state value of one or more of the batteries decreases to or below a predetermined third charge state value during the process of performing the balancing control, and an instruction to interrupt the balancing control if the charge state value decreases to or below the third charge state value.

[0130] The battery management device 700 may further include an input interface device 740, an output interface device 750, a storage device 760, and the like. Each component included in the battery management device 700 can communicate with one another via a bus 770.

[0131] Here, processor 710 can mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which the method according to the embodiment of the present invention is performed. The memory (or storage device) may consist of at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory may consist of at least one of a read-only memory (ROM) and a random access memory (RAM).

[0132] The operation of the method according to the embodiment of the present invention can be embodied as a computer-readable program or code on a computer-readable recording medium. A computer-readable recording medium includes all types of recording devices on which data that can be read by a computer system is stored. Furthermore, computer-readable recording media may be distributed across a network of computer systems, and computer-readable programs or code may be stored and executed in a distributed manner.

[0133] Some aspects of the present invention have been described in the context of apparatus, but they can also be described by corresponding methods, where a block or apparatus corresponds to a method step or a feature of a method step. Similarly, aspects described in the context of a method can be described by corresponding blocks or items or features of corresponding apparatus. Some or all of the method steps can be carried out by (or using) hardware devices such as, for example, a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, one or more of the most important method steps can be carried out by such devices.

[0134] While preferred embodiments of the present invention have been described above with reference to the present invention, those skilled in the art will understand that the present invention can be modified and altered in various ways without departing from the spirit and scope of the invention as set forth in the following claims. [Explanation of Symbols]

[0135] 10:Battery 100: Battery Assembly 200, 700: Battery management device

Claims

1. A battery management device located within a battery system containing multiple batteries, At least one processor, and Includes memory for storing at least one instruction executed through the at least one processor, The at least one instruction is, A command to collect status information including the charge status value of the aforementioned battery, A command to check whether one or more of the charge state values ​​of the aforementioned batteries belong to a predetermined low-charge state interval or high-charge state interval. A command to determine whether the balancing start condition defined in correspondence with the current charging state interval is met, based on the battery state information, and A battery management device including a command to determine whether or not to start a balancing mode for balancing the batteries according to the judgment result.

2. The low-charge state interval is defined as an interval in which the charge state value is less than or equal to a predetermined first charge state value. The battery management device according to claim 1, wherein the high-charge state interval is defined as an interval in which the charge state value is equal to or greater than a preset second charge state value.

3. The conditions for initiating balancing in the aforementioned low-charge state section are: The battery management device according to claim 1, comprising one or more of the following conditions: a first condition in which the difference between the State of Health (SOH) of the battery is within a preset threshold range; a second condition in which the temperature of the battery is above a preset threshold temperature; and a third condition in which the idle period of the battery exceeds a preset first period.

4. The conditions for starting balancing in the aforementioned high-charge state section are: The battery management device according to claim 1, comprising one or more of the following conditions: a second condition that the temperature of the battery is above a preset threshold temperature, and a fourth condition that the battery's idle period exceeds a preset second period.

5. The at least one instruction is, Once the balancing mode is started, a command is issued to determine the battery to be balanced based on the difference between the charge state values ​​of the batteries, and The battery management device according to claim 1, further comprising an instruction to execute a predefined balancing control for the battery to be balanced.

6. The command for determining the battery to be balanced is: When the balancing mode is started in the low-charge state section, a command is given to determine the battery to be balanced as the battery having a charge state value whose difference from the minimum charge state value is equal to or greater than a preset first threshold, and, When the balancing mode is started in the high-charge state section, the command includes determining the battery to be balanced as the battery having a charge state value whose difference from the minimum charge state value is equal to or greater than a preset second threshold, The battery management device according to claim 5, wherein the first threshold is set to a value greater than the second threshold.

7. The instruction that performs the balancing control is: A command to calculate the balancing period based on the capacity of the battery to be balanced, and The battery management device according to claim 5, comprising an instruction to perform the balancing control during the balancing period.

8. The instruction that performs the balancing control is: The battery management device according to claim 5, further comprising a command to monitor whether one or more of the battery charge state values ​​enter the high charge state interval during the process of performing the balancing control.

9. The instruction that performs the balancing control is: The battery management device according to claim 8, which includes an instruction to re-determine the battery to be balanced if one or more of the charge state values ​​of the batteries enter the high charge state section and the balancing start condition in the high charge state section is met.

10. The instruction that performs the balancing control is: During the process of performing the balancing control, a command is given to monitor whether one or more of the charge state values ​​of the batteries decrease to or below a predetermined third charge state value, and The battery management device according to claim 5, which includes an instruction to interrupt the balancing control if the charge level falls below a third charge level.

11. A battery balancing method using a battery management device that manages multiple batteries, A step of collecting status information including the charge state value of the battery, A step of checking whether one or more of the charge state values ​​of the aforementioned batteries belong to a predetermined low-charge state interval or a high-charge state interval. A step of determining whether the balancing start condition defined in correspondence with the current charge state interval is met based on the battery state information, and A battery balancing method comprising the step of determining whether or not to start a balancing mode for balancing the batteries according to the judgment result.

12. The low-charge state interval is defined as an interval in which the charge state value is less than or equal to a predetermined first charge state value. The battery balancing method according to claim 11, wherein the high-charge state interval is defined as an interval in which the charge state value is equal to or greater than a preset second charge state value.

13. The conditions for initiating balancing in the aforementioned low-charge state section are: The battery balancing method according to claim 11, comprising one or more of the following conditions: a first condition in which the difference between the State of Health (SOH) of the batteries is within a preset threshold range; a second condition in which the temperature of the batteries is above a preset threshold temperature; and a third condition in which the idle period of the batteries exceeds a preset first period.

14. The conditions for starting balancing in the aforementioned high-charge state section are: The battery balancing method according to claim 11, comprising one or more of the following conditions: a second condition that the temperature of the battery is above a preset threshold temperature, and a fourth condition that the battery's rest period exceeds a preset second period.

15. Once the balancing mode is started, the process involves determining the battery to be balanced based on the difference between the charge state values ​​of the batteries, and The battery balancing method according to claim 11, further comprising the step of performing a predefined balancing control on the battery to be balanced.

16. The step of determining the battery to be balanced is: When the balancing mode is started in the low-charge state section, the battery having a charge state value whose difference from the minimum charge state value is equal to or greater than a preset first threshold value is determined to be the battery to be balanced, and When the balancing mode is started in the high-charge state section, the process includes the step of determining a battery with a charge state value such that the difference from the minimum charge state value is equal to or greater than a preset second threshold value as the battery to be balanced. The battery balancing method according to claim 15, wherein the first threshold is set to a value greater than the second threshold.

17. The step of performing the balancing control is: A step of calculating the balancing period based on the capacity of the battery to be balanced, and The battery balancing method according to claim 15, further comprising the step of performing the balancing control during the balancing period.

18. The step of performing the balancing control is: The battery balancing method according to claim 15, further comprising the step of monitoring whether one or more of the battery charge state values ​​enter the high charge state interval during the process of performing the balancing control.

19. The step of performing the balancing control is: The battery balancing method according to claim 18, further comprising the step of re-determining the batteries to be balanced if one or more of the charge state values ​​of the batteries enter the high charge state section and the balancing start conditions in the high charge state section are met.

20. The step of performing the balancing control is: During the process of performing the balancing control, the steps include monitoring whether the charge state value of one or more of the batteries decreases to or below a predetermined third charge state value, and The battery balancing method according to claim 15, further comprising the step of interrupting the balancing control if the charge level falls below a third charge level.

21. Multiple batteries, and Includes a battery management device that collects the state information of the battery and manages and controls the battery based on the collected state information, The aforementioned battery management device, A battery system that checks whether one or more of the charge state values ​​of the batteries belong to a predetermined low charge state interval or high charge state interval, determines whether the balancing start conditions defined in correspondence with the current charge state interval are met based on the battery state information, and determines whether or not to start a balancing mode for balancing the batteries according to the determination result.

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