SOC determination device and SOC determination method for battery bank

Abstract

A state of charge (SOC) determination method and an SOC determination apparatus for a battery compartment are provided. A SOC determination method according to the present disclosure includes determining that a first SOC is equal to an average SOC of a plurality of battery packs. When the first SOC differs from or exceeds a reference SOC range, the SOC determination method further includes determining that the second SOC is equal to a maximum SOC or a minimum SOC of the plurality of battery packs, and determining an SOC of the battery bank by applying a weighted summation operation to the first SOC and the second SOC.

Description

Technical Field

[0001] This disclosure relates to the determination of the state of charge (SOC) of a battery bank comprising multiple battery packs.

[0002] This application is based on and claims priority to Korean Patent Application No. 10-2024-0047587 filed in Korea on April 8, 2024 and Korean Patent Application No. 10-2025-0039660 filed on March 27, 2025, the disclosures of which are incorporated herein by reference. Background Technology

[0003] In recent years, the demand for portable electronic products such as laptops, cameras and mobile phones has grown rapidly, and with the widespread development of electric vehicles, energy storage devices, robots and satellites, there is a great deal of research being conducted on high-performance batteries that can be repeatedly charged and discharged.

[0004] Currently, batteries on the market include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium batteries. Among them, lithium batteries have little or no memory effect, and therefore they receive more attention than nickel-based batteries due to the following advantages: they can be easily recharged at any time, have a very low self-discharge rate, and have high energy density.

[0005] In recent years, to achieve stable power management, it has been important not only for energy storage systems but also for electric vehicles to achieve the highest possible capacity. Therefore, a common control method is to selectively connect one or more of the multiple battery packs in a battery bank, which are installed in series, parallel, or both, according to the external power required.

[0006] Excessively high or low state of charge (SOC) can accelerate degradation, leading to uneven degradation across multiple battery packs, increasing the risk of explosion, and significantly reducing the overall charge / discharge performance of the battery bank. Therefore, it is necessary to control the battery bank to ensure that the SOC of each battery pack is within the optimal range and to reduce the SOC deviation between multiple battery packs.

[0007] There may be some differences between the average SOC of multiple battery packs and the SOC of an individual battery pack. When the SOC of at least one of the multiple battery packs exceeds the optimal SOC range, immediately stopping the charging or discharging of the battery pack can prevent the above problems to some extent.

[0008] However, when the average SOC is used to inform the user of the battery bank's SOC or to control the battery system, even if the average SOC (e.g., 98%) is within the optimal SOC range, charging or discharging may suddenly stop because the SOC of at least one battery pack (e.g., 100%) exceeds the optimal SOC range, causing some unexpected inconvenience to the battery bank's user and posing a serious safety threat to the battery system. Summary of the Invention

[0009] Technical issues

[0010] This disclosure is designed to address the aforementioned problems, and therefore aims to provide an apparatus and method for determining the state of charge (SOC) of a battery bank comprising multiple battery packs based on SOC factors (e.g., average SOC, maximum SOC, and / or minimum SOC) to a value that better satisfies the charge / discharge operating conditions of the battery bank compared to these SOC factors.

[0011] These and other objectives and advantages of this disclosure will be understood from the following description and will become apparent from embodiments of this disclosure. Furthermore, it will be readily understood that the objectives and advantages of this disclosure can be achieved by the means and combinations thereof set forth in the appended claims.

[0012] Technical solution

[0013] A method for determining the state of charge (SOC) of a battery bank comprising multiple battery packs, according to one aspect of this disclosure, includes determining a first SOC equal to the average SOC of the multiple battery packs. When the first SOC differs from or exceeds a reference SOC range, the SOC determination method further includes determining a second SOC equal to the maximum or minimum SOC of the multiple battery packs, depending on whether the battery bank is being charged or discharged, and determining the SOC of the battery bank by applying a weighted summation operation to the first and second SOCs.

[0014] Determining the SOC of the battery library may include determining a first weight and a second weight based on a second SOC, and determining the SOC of the battery library by applying the first weight and the second weight to the first SOC and the second SOC, respectively.

[0015] When the battery bank is being charged and the first SOC is greater than the reference SOC or the upper limit of the reference SOC range, determining the first weight and the second weight may include determining the second weight by applying a predetermined positive correspondence to the second SOC, and determining the first weight as a value whose sum with the second weight equals a predetermined set value.

[0016] When the battery bank is being discharged and the first SOC is less than the reference SOC or the lower limit of the reference SOC range, determining the first weight and the second weight may include determining the first weight by applying a predetermined positive correspondence to the second SOC, and determining the second weight as a value whose sum with the first weight is equal to a predetermined set value.

[0017] When the battery bank is being charged and the first SOC is greater than the reference SOC or the upper limit of the reference SOC range, determining the first weight and the second weight may include determining the first weight by applying a predetermined negative correspondence to the second SOC, and determining the second weight as a value whose sum with the first weight is equal to a predetermined set value.

[0018] When the battery bank is being discharged and the first SOC is less than the reference SOC or the upper limit of the reference SOC range, determining the first weight and the second weight may include determining the second weight by applying a predetermined negative correspondence to the second SOC, and determining the first weight as a value whose sum with the second weight equals a predetermined set value.

[0019] The SOC determination method may also include determining that the SOC of the battery bank is equal to the first SOC when the first SOC is equal to or falls within the range of the reference SOC.

[0020] Determining the second SOC may include: determining that the second SOC is equal to the maximum SOC when the battery bank is being charged, and determining that the second SOC is equal to the minimum SOC when the battery bank is being discharged.

[0021] The SOC determination method may also include stopping charging or discharging the battery bank when the SOC of the battery bank reaches the upper or lower limit of the allowable SOC range or exceeds the allowable SOC range.

[0022] A method for determining the State of Charge (SOC) of a battery bank comprising multiple battery packs, according to another aspect of this disclosure, includes determining a first SOC equal to the average SOC of the multiple battery packs. When the first SOC differs from or exceeds a reference SOC range, the SOC determination method further includes: determining a second SOC equal to the maximum or minimum SOC of the multiple battery packs, depending on whether the battery bank is being charged or discharged; determining a first weight and a second weight based on the second SOC; determining a third SOC by applying a first weighted summation operation to the first and second SOCs; and determining the SOC of the battery bank by applying a second weighted summation operation to the third SOC and a previous SOC of the battery bank.

[0023] The method for determining SOC may also include determining that the third SOC is equal to the first SOC when the first SOC is equal to or falls within the range of the reference SOC.

[0024] Determining the SOC of the battery library includes determining a third weight and a fourth weight based on the difference between the third SOC and the previous SOC of the battery library, and determining the SOC of the battery library by applying the third weight and the fourth weight to the third SOC and the previous SOC of the battery library, respectively.

[0025] According to another aspect of this disclosure, an apparatus for determining the State of Charge (SOC) of a battery bank comprising multiple battery packs includes a processor configured to determine that a first SOC is equal to the average SOC of the multiple battery packs. When the first SOC differs from or exceeds a reference SOC range, the processor is configured to perform the following operations: determining a second SOC equal to the maximum or minimum SOC of the multiple battery packs, depending on whether the battery bank is being charged or discharged; and determining the SOC of the battery bank by applying a weighted summation operation to the first SOC and the second SOC.

[0026] According to another aspect of this disclosure, an apparatus for determining the State of Charge (SOC) of a battery bank comprising multiple battery packs includes a processor configured to determine that a first SOC is equal to the average SOC of the multiple battery packs. When the first SOC differs from or exceeds a reference SOC range, the processor is configured to perform the following operations: determining a second SOC equal to the maximum or minimum SOC of the multiple battery packs, depending on whether the battery bank is being charged or discharged; determining a third SOC by applying a first weighted summation operation to the first and second SOCs; and determining the SOC of the battery bank by applying a second weighted summation operation to the third SOC and the previous SOC of the battery bank.

[0027] According to another aspect of this disclosure, the battery system includes a SOC determination device.

[0028] Beneficial effects

[0029] According to at least one embodiment of this disclosure, the SOC of the battery bank can be determined by applying mathematical operations corresponding to the charging / discharging operating conditions of the battery bank to the state of charge (SOC) factors (e.g., average SOC, maximum SOC, and / or minimum SOC) of the multiple battery packs included in the battery bank, to a value that better satisfies the charging / discharging operating conditions of the battery bank compared to these SOC factors.

[0030] The state of charge (SOC) of the battery bank as determined by this disclosure can replace the SOC factor in determining whether to stop charging or discharging the battery bank, thereby preventing sudden cessation of charging or discharging.

[0031] The effects of the embodiments disclosed herein are not limited to those described above, and those skilled in the art will clearly understand these and other effects from the appended claims. Attached Figure Description

[0032] The accompanying drawings illustrate exemplary embodiments of the present disclosure and, together with the following detailed description, are intended to provide a better understanding of the technical aspects of the present disclosure; therefore, the present disclosure should not be construed as being limited to the drawings.

[0033] Figure 1 This is a diagram illustrating, by way of example, the architecture of the battery system 1 according to the present disclosure.

[0034] Figure 2 This is a flowchart illustrating, by way of example, a method for determining the state of charge (SOC) according to a first embodiment of the present disclosure.

[0035] Figure 3 This is an example showing that it can be done Figure 2 The flowchart shows an example of a subroutine executed in step S242 of the method.

[0036] Figure 4 In describing Figure 3 The method is based on the diagram.

[0037] Figure 5 It is a schematic representation that can be Figure 2 The flowchart shows another example of the subroutine executed in step S242 of the method.

[0038] Figure 6 In describing Figure 5 The method is based on the diagram.

[0039] Figure 7 It is a schematic representation that can be Figure 2 The flowchart shows another example of the subroutine executed in step S242 of the method.

[0040] Figure 8 It is a schematic representation that can be Figure 2 The flowchart shows another example of the subroutine executed in step S242 of the method.

[0041] Figure 9 This is a flowchart illustrating, by way of example, a SOC determination method according to a second embodiment of the present disclosure.

[0042] Figure 10 This is a flowchart illustrating, by way of example, a SOC determination method according to a third embodiment of the present disclosure.

[0043] Figure 11 This is a flowchart illustrating, by way of example, a SOC determination method according to a fourth embodiment of the present disclosure. Detailed Implementation

[0044] In the following, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before the description, it should be understood that the terms or words used in this specification and the appended claims should not be construed as limited to their general and dictionary meanings, but should be interpreted based on their meanings and concepts corresponding to the technical aspects of the present disclosure, on the basis of the principle that the inventors are allowed to appropriately define the terms for the best interpretation.

[0045] Therefore, the embodiments described herein and the illustrations shown in the accompanying drawings are exemplary embodiments of this disclosure, used to describe the technical aspects of this disclosure, and are not intended to be restrictive. It should be understood that various other equivalents and modifications may be made thereto when this application is filed.

[0046] Terms including ordinal numbers such as “first” and “second” are used to distinguish one element from another among the various elements, rather than to limit the elements by these terms.

[0047] Unless the context clearly indicates otherwise, the terms “comprising” and “including” as used in this specification specify the presence of the stated elements without excluding the presence or addition of one or more other elements. Furthermore, as used herein, the term “unit” refers to a processing unit that performs at least one function or operation and may be implemented by hardware and software, alone or in combination.

[0048] Furthermore, throughout this specification, it will be further understood that when an element is referred to as being “connected to” another element, it can be directly connected to that other element or there can be an intermediate element.

[0049] Figure 1 This is a diagram illustrating, by way of example, the architecture of the battery system 1 according to the present disclosure.

[0050] refer to Figure 1 The battery system 1 includes a battery bank BB, a battery monitoring device 120, and a power conversion system 10.

[0051] The power conversion system 10 is electrically connected between the battery bank BB and the power grid 2 and / or the electrical load 3.

[0052] The power conversion system 10 uses a DC-AC inverter and / or DC-DC converter equipped therein to handle power transfer between the battery bank BB and the power grid 2 and / or between the battery bank BB and the electrical load 3. That is, during operation in battery charging mode, the power conversion system 10 can convert AC power supplied from the power grid 2 into DC power and supply it to the battery bank BB.

[0053] Furthermore, during operation in battery discharge mode, the power conversion system 10 can convert the DC input power generated by the discharge of the battery bank BB into AC power and supply it to the power grid 2 and / or the electrical load 3.

[0054] The battery monitoring device 120 can acquire the status information of the battery bank BB and send charging commands, discharging commands, and / or standby commands to the power conversion system 10 based on the acquired status information. In response to the charging command, the power conversion system 10 can operate the DC-AC inverter in battery charging mode. In response to the discharging command, the power conversion system 10 can operate the DC-AC inverter in battery discharging mode.

[0055] A charging command is a signal requesting DC power supply to battery bank BB. A discharging command is a signal requesting the release of DC power from battery bank BB. A standby command is a signal requesting the cessation of both charging and discharging operations.

[0056] The battery pack BB comprises multiple battery packs BG_1 to BG_m. m is a natural number of 2 or greater. In this specification, the symbol "BG" is appended to the battery pack in the description shared among the multiple battery packs BG_1 to BG_m. Depending on the application in which the battery pack BG is used, the battery pack BG may be referred to as a "battery pack" or a "battery rack".

[0057] For ease of description, although Figure 1 It is shown that m=6, that is, the battery library BB includes a total of six battery packs BG_1~BG_6, but the number of battery packs BG is not limited to a specific number and can be two or more.

[0058] A battery pack (BG) comprises one battery cell (BC) or two or more battery cells (BC) connected in series. In this specification, a battery cell (BC) refers to the basic unit of a battery and the smallest independent component that can be charged and discharged, and is not limited to a specific type and can include any rechargeable battery, such as a lithium-ion cell.

[0059] When the battery monitoring device 120 performs the state of charge (SOC) determination method as described below, the battery monitoring device 120 may be referred to as an "SOC determination device".

[0060] The battery monitoring device 120 can be configured to control the charging and discharging of multiple battery packs BG_1 to BG_m to suppress SOC deviation and / or state of health (SOH) deviation among the multiple battery packs BG_1 to BG_m.

[0061] The battery monitoring device 120 includes a processor 400. The battery monitoring device 120 may also include at least one of a plurality of switches 200_1 to 200_m and / or a plurality of sensing circuits 300_1 to 300_m.

[0062] Multiple switches 200_1~200_m are connected in series with multiple battery packs BG_1~BG_m in a one-to-one relationship. That is, any two or more battery packs BG_1~BG_m can be connected in parallel through multiple switches 200_1~200_m.

[0063] In this specification, the symbol "200" is appended to the description shared among the multiple switches 200_1 to 200_m. Switch 200 is not limited to a particular type and can include any type of switch that turns the current path between the battery pack BG and the power conversion system 10 on or off. As an example, switch 200 may include a semiconductor switch, such as a metal-oxide-semiconductor field-effect transistor (MOSFET), or a mechanical switch, such as a relay. As another example, switch 200 may include a bidirectional DC-DC converter.

[0064] When i is assumed to be a natural number equal to or less than m, battery pack BG_i can be charged and discharged simultaneously when switch 200_i is turned on. When switch 200_i is turned off, battery pack BG_i is electrically isolated from other battery packs in battery bank BB, and also from power conversion system 10.

[0065] Multiple sensing circuits 300_1 to 300_m are respectively provided to multiple battery packs BG_1 to BG_m. In this specification, in the description shared by the multiple sensing circuits 300_1 to 300_m, the symbol "300" is attached to the sensing circuit.

[0066] Sensing circuit 300 includes a voltage sensor 310 and a current sensor 320. Sensing circuit 300 uses voltage sensor 310 and current sensor 320 to measure the voltage and current of the connected battery pack BG. Voltage sensor 310 is connected in parallel to battery pack BG and measures the voltage across battery pack BG. Current sensor 320 is mounted in the power line connecting battery pack BG to switch 200 and measures the current flowing through battery pack BG. Sensing circuit 300 generates sensing signals indicating the measured voltage and measured current. The sensing signals can indicate a pair of voltage and current values ​​detected simultaneously.

[0067] The processor 400 can be individually and operably coupled to multiple switches 200_1~200_m, multiple sensing circuits 300_1~300_m, and the power conversion system 10. Here, "operably coupled" means to realize a connection for signal transmission and reception in one or two directions.

[0068] The processor 400 may be implemented in hardware using at least one of the following: application-specific integrated circuit (ASIC), digital signal processor (DSP), digital signal processing device (DSPD), programmable logic device (PLD), field-programmable gate array (FPGA), microprocessor, or electronic unit for performing other functions.

[0069] Processor 400 may have a memory device. The memory device may include at least one type of storage medium, such as flash memory, hard disk drive, solid-state drive (SSD), silicon disk drive (SDD), multimedia card microdisk, random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), or programmable read-only memory (PROM). The memory device may store data and programs required for operations performed by processor 400. The memory device may also store data indicating the results of operations performed by processor 400.

[0070] The processor 400 can periodically collect sensing signals from each of the multiple sensing circuits 300_1 to 300_m. The processor 400 can determine the SOC of each of the multiple battery packs BG_1 to BG_m based on the sensing signals and additionally determine the SOH.

[0071] State of Charge (SOC) indicates the ratio of remaining capacity to maximum capacity and is typically expressed as a range between 0% and 100%. Remaining capacity indicates the amount of charge currently stored in the battery pack (BG).

[0072] SOH indicates the ratio of maximum capacity to design capacity and is typically expressed as a range between 0% and 100%. Design capacity indicates the maximum amount of charge that can be stored in the battery pack (BG) when it is brand new. Maximum capacity indicates the maximum amount of charge that can be stored in the battery pack (BG) as it begins to degrade from its initial state. As the battery pack (BG) degrades, the maximum capacity gradually decreases from the design capacity. Each of SOC and SOH can be estimated using various known techniques or combinations thereof, and their detailed descriptions are omitted here.

[0073] In the following text, reference will be made to Figures 2 to 11 Various embodiments for determining the State of Charge (SOC) of battery bank BB based on its charging / discharging operating conditions are described. Charging / discharging operating conditions can be terms indicating the operating state of battery bank BB, such as whether battery bank BB is being charged or discharged, or the SOC of at least one of multiple battery packs BG_1 to BG_m.

[0074] Figure 2 This is a flowchart illustrating, by way of example, a SOC determination method according to a first embodiment of the present disclosure. Figure 2 The method can be derived from Figure 1 The battery monitoring device 120 shown in the figure performs this function. The battery monitoring device 120 can periodically determine the SOC of each battery pack during the charging or discharging of the battery bank BB.

[0075] See Figure 1 and Figure 2 In step S210, the processor 400 determines that the first SOC is equal to the average SOC of the multiple battery packs BG_1 to BG_m. For example, the first SOC may indicate the arithmetic mean or harmonic mean of the SOCs of the multiple battery packs BG_1 to BG_m.

[0076] In step S220, the processor 400 determines whether the first SOC is equal to the reference SOC. The reference SOC may be preset to the median (e.g., 50%) of a predetermined allowable SOC range (e.g., 0% to 100%, or 2% to 98%) of the battery pack BG. A value of "No" in step S220 indicates that the first SOC is different from the reference SOC. When the value of step S220 is "No", step S230 is executed. When the value of step S220 is "Yes", step S250 is executed.

[0077] In step S230, the processor 400 determines the second SOC to be equal to the maximum or minimum SOC of the multiple battery packs BG_1 to BG_m, depending on whether the battery bank BB is being charged or discharged. As an example, when the battery bank BB is being charged, the maximum SOC of the multiple battery packs BG_1 to BG_m can be determined as the second SOC. As another example, when the battery bank BB is discharging, the minimum SOC of the multiple battery packs BG_1 to BG_m can be determined as the second SOC.

[0078] In step S240, the processor 400 determines the SOC of the battery bank BB by applying a weighted summation operation to the first SOC and the second SOC (see relations 1 to 4 described below). Step S240 may include steps S242 and S244.

[0079] In step S242, the processor 400 determines a first weight and a second weight based on the second SOC. The first weight can be used for the first SOC, and the second weight can be used for the second SOC. Step S242 will be referred to below. Figure 4 and Figure 8 Describe it.

[0080] In step S244, the processor 400 determines the SOC of the battery bank BB by applying a first weight and a second weight to the first SOC and the second SOC, respectively. That is, the SOC of the battery bank BB can indicate a weighted sum of the first SOC and the second SOC using the first weight and the second weight.

[0081] In step S250, the processor 400 determines whether the SOC of the battery library BB is equal to the first SOC. The SOC of the battery library BB may be referred to, for example, as "library SOC", "representative SOC" or "system SOC".

[0082] Figure 3 It is a schematic representation that can be Figure 2 The flowchart shows an example of the subroutine executed in step S242 of the method, and Figure 4 In describing Figure 3 The method is based on the diagram.

[0083] refer to Figure 3 In step S310, the processor 400 determines whether the battery bank BB is being charged and whether the first SOC is greater than the reference SOC. When the battery bank BB is being discharged or is at rest, or when the first SOC is less than the reference SOC, the value of step S310 is "No". When the value of step S310 is "Yes", step S320 is executed. Figure 4 The case where m=5 and the first SOC=62% is shown. When the reference SOC=50%, the output value of step S310 is "Yes".

[0084] In step S320, the processor 400 determines the second weight by applying a predetermined first positive correspondence to the second SOC (e.g., the maximum SOC).

[0085] The following relation 1 can be an example of the first positive correspondence relation.

[0086] <Relation 1>

[0087] In relation 1, x represents the second SOC, U A A represents a preset positive integer. k This represents the predetermined k-th coefficient corresponding to index k, A0 represents a predetermined positive number (e.g., 0.5) equal to or greater than the reference value corresponding to the reference SOC, and y A (x) represents the second weight. y A The maximum value of (x) can be limited to a predetermined set value (e.g., 1).

[0088] The first positive correspondence is not limited to relation 1. When the second SOC lies between the reference SOC and the upper limit of the allowable SOC range, any mathematical operation other than relation 1 that makes the second weight increase with the increase of the second SOC can be used in the first positive correspondence.

[0089] In step S330, the processor 400 determines the first weight as a value whose sum with the second weight determined in step S320 equals a set value. That is, the second weight = set value - the first weight.

[0090] Figure 5 It is a schematic representation that can be Figure 2 The flowchart shows another example of the subroutine executed in step S242 of the method, and Figure 6 In describing Figure 5 The method is based on the diagram.

[0091] refer to Figure 5 In step S510, the processor 400 determines whether the battery bank BB is being discharged and whether the first SOC is less than the reference SOC. When the battery bank BB is being charged or in a resting state, or when the first SOC is greater than the reference SOC, the value of step S510 is "No". When the value of step S510 is "Yes", step S520 is executed. Figure 6 The case where m=5 and the first SOC=39% is shown. When the reference SOC=50%, the output value of step S510 is "Yes".

[0092] In step S520, the processor 400 determines the first weight by applying a predetermined second positive correspondence to the second SOC (e.g., the minimum SOC).

[0093] The following relation 2 can be an example of the second positive correspondence relation.

[0094] <Relation 2>

[0095] In relation 2, x represents the second SOC, U B B represents a preset positive integer. k Let B0 represent the predetermined k-th coefficient corresponding to index k, and let B0 represent a predetermined constant less than the reference value, and y B (x) represents the first weight. y B The maximum value of (x) can be limited to a reference value. B0 can be equal to a ratio value (e.g., 0, 0.02) corresponding to the lower limit of the allowable SOC range (e.g., 0%, 2%).

[0096] The second positive correspondence is not limited to relation 2. When the second SOC lies between the lower limit of the allowable SOC range and the reference value, any mathematical operation other than relation 2 that makes the first weight decrease as the second SOC decreases can be used for the second positive correspondence.

[0097] In step S530, the processor 400 determines the second weight as a value whose sum with the first weight determined in step S520 equals a predetermined set value. That is, second weight = set value - first weight. Because the second positive correspondence causes the first weight to decrease as the second SOC decreases, the second weight determined in step S530 can be larger as the second SOC decreases.

[0098] Figure 7 It is a schematic representation that can be Figure 2 The flowchart shows another example of the subroutine executed in step S242 of the method. To aid understanding, the description... Figure 7 When using this method, you can refer to it again. Figure 4 .

[0099] refer to Figure 7 In step S710, the processor 400 determines whether the battery bank BB is being charged and whether the first SOC is greater than the reference SOC. When the value of step S710 is "yes", step S720 is executed.

[0100] In step S720, the processor 400 determines the first weight by applying a predetermined first negative correspondence to the second SOC (e.g., the maximum SOC).

[0101] The following relation 3 can be an example of the first negative correspondence relation.

[0102] <Relationship 3>

[0103] In relation 3, x represents the second SOC, U C Represents a preset positive integer, C k C0 represents the preset k-th coefficient corresponding to index k, C0 represents the preset constant (e.g., equal to the reference value), and y C (x) represents the first weight. y C The maximum value of (x) can be restricted to a reference value.

[0104] The first negative correspondence is not limited to relation 3. When the second SOC lies between the lower limit of the allowable SOC range and the reference value, any mathematical operation other than relation 3 that makes the first weight decrease as the second SOC increases can be used for the first negative correspondence.

[0105] In step S730, the processor 400 determines the second weight as a value whose sum with the first weight determined in step S720 equals a preset value. Because the first negative correspondence causes the first weight to decrease as the second SOC increases, the second weight determined in step S730 can be larger as the second SOC increases.

[0106] Figure 8 It is a schematic representation that can be Figure 2 The flowchart shows another example of the subroutine executed in step S242 of the method. In the description Figure 8 When using this method, you can refer to it again. Figure 6 .

[0107] refer to Figure 8 In step S810, the processor 400 determines whether the battery bank BB is being discharged and whether the first SOC is less than the reference SOC. When the value of step S810 is "yes", step S820 is executed.

[0108] In step S820, the processor 400 determines the second weight by applying a predetermined second negative correspondence to the second SOC (e.g., the minimum SOC).

[0109] The following relation 4 can be an example of the second negative correspondence relation.

[0110] <Relation 4>

[0111] In relation 4, x represents the second SOC, U D D represents a preset positive integer. k Let yD(x) represent the predetermined k-th coefficient corresponding to index k, D0 represent a preset constant (e.g., equal to a set value), and yD(x) represent the second weight. The maximum value of yD(x) can be limited to a set value.

[0112] The second negative correspondence is not limited to relation 4. When the second SOC lies between the reference value and the lower limit of the allowable SOC range, any mathematical operation other than relation 4 that makes the second weight increase as the second SOC decreases can be used for the second negative correspondence.

[0113] In step S830, the processor 400 determines the first weight as a value whose sum with the second weight determined in step S820 equals a predetermined set value. Because the second negative correspondence causes the second weight to increase as the second SOC decreases, the first weight determined in step S830 can be smaller as the second SOC decreases.

[0114] when Figure 3 The value of step S310 in the middle, Figure 6The value of step S510 in the middle, Figure 7 The value of step S710 or Figure 8 If the value of step S810 is "No", then the following can be executed. Figure 2 Step S250.

[0115] When passing Figure 3 , Figure 5 , Figure 7 or Figure 8 When determining the first and second weights using the method, Figure 2 The SOC of the battery library BB determined in step S244 can satisfy the following relationship 5.

[0116] <Relation 5>

[0117] In relation 5, SOC Bank It's the SOC of the battery bank BB. 1_G It is the first SOC, SOC 2_G It is the second SOC, w1 is the first weight, and w2 is the second weight.

[0118] Based on the above, when battery bank BB is being charged, the SOC of battery bank BB can be determined to be equal to the upper limit of the allowable SOC range before or when the second SOC reaches the upper limit of the allowable SOC range. Therefore, it is possible to prevent the SOC of at least one battery pack from reaching the upper limit of the allowable SOC range before the average SOC reaches the upper limit of the allowable SOC range, thereby automatically avoiding a sudden stop in charging of battery bank BB.

[0119] While battery bank BB is being discharged, the SOC of battery bank BB can be determined to be equal to the lower limit of the allowable SOC range before or when the second SOC reaches the lower limit of the allowable SOC range. Therefore, it is possible to prevent the SOC of at least one battery pack from reaching the lower limit of the allowable SOC range before the average SOC reaches the lower limit of the allowable SOC range, thereby automatically avoiding the sudden stop of discharge of battery bank BB.

[0120] For reference, w1 and w2 could be due to execution Figure 3 , Figure 5 , Figure 7 and Figure 8 Obtained by any one of them. That is, by means of... Figure 3 , Figure 5 , Figure 7 and Figure 8 The combination of the first weight obtained by any of the four methods and the second weight obtained by any of the other three methods shall not be used as w1 and w2 in relation 5.

[0121] Figure 9 This is a flowchart illustrating, by way of example, a SOC determination method according to a second embodiment of the present disclosure. Figure 9 The method can be derived from Figure 1 The battery monitoring device 120 shown in the figure performs this function. The battery monitoring device 120 can periodically determine the SOC of each battery pack during the charging of the battery bank BB.

[0122] See Figure 1 and Figure 9 In step S910, the processor 400 determines that the first SOC is equal to the average SOC of the multiple battery packs BG_1 to BG_m.

[0123] In step S920, the processor 400 determines whether the first SOC is within the reference SOC range. The reference SOC range can be preset to be narrower than the preset allowable SOC range of the battery pack BG. The upper limit of the reference SOC range can be referred to as the first reference SOC (e.g., 60%), and the lower limit of the reference SOC range can be referred to as the second reference SOC (e.g., 40%). That is, when the first SOC is equal to or less than the first reference SOC and equal to or greater than the second reference SOC, the value of step S920 is "yes". When the value of step S920 is "no", step S930 is executed. When the value of step S920 is "yes", step S950 is executed.

[0124] In step S930, the processor 400 determines the second SOC to be equal to the maximum or minimum SOC of the multiple battery packs BG_1 to BG_m, depending on whether the battery bank BB is being charged or discharged.

[0125] In step S940, the processor 400 determines the SOC of the battery bank BB by applying a weighted summation operation to the first SOC and the second SOC. Step S940 may include steps S942 and S944.

[0126] In step S942, the processor 400 determines a first weight and a second weight. The first weight can be used for a first SOC, and the second weight can be used for a second SOC.

[0127] In step S944, the processor 400 determines the SOC of the battery bank BB by applying a first weight and a second weight to the first SOC and the second SOC, respectively.

[0128] In step S950, the processor 400 determines the SOC of the battery bank BB to be equal to the first SOC.

[0129] At the same time, refer to Figures 3 to 8The description of the first embodiment can be equally applied to the above references with the following modifications. Figure 9 Step S942 of the second embodiment described.

[0130] Will Figure 3 and Figure 7 The method is applied to Figure 9 The modification required for step S942 may be to refer to Figure 3 and Figure 7 The terms "reference SOC" and "reference value" in the description are replaced with "first reference SOC" and "first reference value," respectively. Here, the first reference value can be a ratio value between 0 and 1 corresponding to the first reference SOC. For example, when the first reference SOC is 60%, the first reference value can be 0.6.

[0131] Will Figure 5 and Figure 8 The method is applied to Figure 9 The modification required for step S942 may be to refer to Figure 5 and Figure 8 The terms "reference SOC" and "reference value" in the description are replaced with "second reference SOC" and "second reference value," respectively. Here, the second reference value can be a ratio value between 0 and 1 corresponding to the second reference SOC. For example, when the second reference SOC is 40%, the first reference value can be 0.4.

[0132] Figure 10 This is a flowchart illustrating, by way of example, a SOC determination method according to a third embodiment of the present disclosure. Figure 10 The method can be derived from Figure 1 The battery monitoring device 120 shown in the figure performs this function. The battery monitoring device 120 can periodically determine the SOC of each battery pack during the charging or discharging of the battery bank BB.

[0133] See Figure 1 and Figure 10 In step S1010, the processor 400 determines that the first SOC is equal to the average SOC of the multiple battery packs BG_1 to BG_m.

[0134] In step S1020, the processor 400 determines whether the first SOC is equal to the reference SOC. If the value of step S1020 is "no", then step S1030 is executed. If the value of step S1020 is "yes", then step S1050 is executed.

[0135] In step S1030, the processor 400 determines the second SOC to be equal to the maximum or minimum SOC of the multiple battery packs BG_1 to BG_m, depending on whether the battery bank BB is being charged or discharged.

[0136] In step S1040, the processor 400 determines the third SOC by applying a first weighted summation operation to the first SOC and the second SOC. Step S1040 may include steps S1042 and S1044.

[0137] In step S1042, the processor 400 determines the first weight and the second weight based on the second SOC.

[0138] Figure 10 Steps S1010, S1020, S1030, and S1042 can be respectively connected with... Figure 2 Steps S210, S220, S230 and S242 are basically the same.

[0139] In step S1044, the processor 400 determines the third SOC by applying the first weight and the second weight to the first SOC and the second SOC, respectively. The third SOC can be equal to the SOC of the battery bank BB determined in step S244. That is, relation 5 can be used as the first weighted summation operation in step S1040, and in this case, the SOC in relation 5 is... Bank The third SOC is indicated; the third SOC is a provisional SOC prior to determining the SOC of the battery bank BB.

[0140] In step S1050, the processor 400 determines that the third SOC is equal to the first SOC.

[0141] In step S1060, the processor 400 determines the SOC of the battery bank BB by applying a second weighted summation operation to the third SOC and the previous SOC of the battery bank BB. Since the SOC of the battery bank BB is updated periodically, in step S1062, the SOC is determined by... Figure 10 The SOC of the battery library BB determined in the previous cycle can be used as the previous SOC.

[0142] Step S1060 may include steps S1062 and S1064.

[0143] In step S1062, the processor 400 determines a third weight and a fourth weight based on the difference between the third SOC and the previous SOC of the battery bank BB. The sum of the third weight and the fourth weight can be equal to a set value.

[0144] The processor 400 can determine a third weight by applying a predetermined third positive correspondence to the difference (which may be an absolute value) between the third SOC and the previous SOC of the battery bank BB, either (i) when the battery bank BB is being charged and the third SOC is greater than the previous SOC of the battery bank BB, or (ii) when the battery bank BB is being discharged and the third SOC is less than the previous SOC of the battery bank BB. In this case, the fourth weight can be determined as equal to the value obtained by subtracting the third weight determined using the third positive correspondence from a set value. The following relation 6 can be an example of the third positive correspondence.

[0145] <Relation 6>

[0146] In relation 6, SOC 3_G Indicates the third SOC, SOC Bank_prv Let 'x' represent the previous SOC of battery BB, and 'x' represent the difference between the third SOC and the previous SOC. U E Represents a preset positive integer, and E k This represents the preset k-th coefficient corresponding to index k. E (x) represents the third weight. E0 can be a preset positive number less than the set value (e.g., half of the set value). y E The minimum value of (x) can be restricted to E0. E The maximum value of (x) can be limited to a first threshold. The first threshold can be a preset value that is less than or equal to a set value. That is, when y is calculated using the third positive correspondence... E When (x) is greater than the first threshold, the third weight can be determined to be equal to the first threshold.

[0147] Alternatively, the processor 400 may determine a fourth weight by applying a predetermined third negative correspondence to the difference (which may be an absolute value) between the third SOC and the previous SOC of the battery bank BB when (i) the battery bank BB is being charged and the third SOC is greater than the previous SOC of the battery bank BB, or (ii) the battery bank BB is being discharged and the third SOC is less than the previous SOC of the battery bank BB. In this case, the third weight may be determined as equal to the value obtained by subtracting the fourth weight determined using the third negative correspondence from a set value. The following relation 7 may be an example of the third negative correspondence.

[0148] <Relation 7>

[0149] In relation 7, U F F represents a preset positive integer. ky represents the predetermined k-th coefficient corresponding to index k. F (x) represents the fourth weight, and F0 represents a preset positive number less than the set value (e.g., half of the set value). x in relation 7 can be equal to x in relation 6. F The minimum value of (x) can be restricted to a second threshold. The second threshold can be a preset positive number less than F0. That is, when y is calculated using the third positive correspondence... F When (x) is less than the second threshold, the fourth weight can be determined to be equal to the second threshold.

[0150] In step S1064, the processor 400 determines the SOC of the battery bank BB by applying the third weight and the fourth weight to the third SOC and the previous SOC of the battery bank BB, respectively.

[0151] The following relation 8 is an example of the second weighted summation operation that can be used in step S1060.

[0152] <Relation 8>

[0153] In relation 8, SOC Bank This indicates the SOC of battery BB. 3_G Indicates the third SOC, SOC Bank_prv This represents the previous SOC of the battery library BB. w3 is the third weight, and w4 is the fourth weight.

[0154] Figure 11 This is a flowchart illustrating, by way of example, a SOC determination method according to a fourth embodiment of the present disclosure. Figure 11 The method can be derived from Figure 1 The battery monitoring device 120 shown in the figure performs this function. The battery monitoring device 120 can periodically determine the SOC of each battery pack during the charging or discharging of the battery bank BB.

[0155] See Figure 1 and Figure 11 In step S1110, the processor 400 determines that the first SOC is equal to the average SOC of the multiple battery packs BG_1 to BG_m.

[0156] In step S1120, the processor 400 determines whether the first SOC is within the range of the reference SOC. That is, when the first SOC is equal to or less than the first reference SOC and equal to or greater than the second reference SOC, the value of step S1120 is "yes". When the value of step S1120 is "no", step S1130 is executed. When the value of step S1120 is "yes", step S1150 is executed.

[0157] In step S1130, the processor 400 determines the second SOC to be equal to the maximum or minimum SOC of the multiple battery packs BG_1 to BG_m, depending on whether the battery bank BB is being charged or discharged.

[0158] In step S1140, the processor 400 determines the third SOC by applying a first weighted summation operation to the first SOC and the second SOC (see relations 1 to 4 above). Step S1140 may include steps S1142 and S1144.

[0159] In step S1142, the processor 400 determines the first weight and the second weight based on the second SOC.

[0160] Figure 11 Steps S1110, S1120, S1130, and S1142 can be respectively connected with Figure 9 The steps S910, S920, S930 and S942 are basically the same.

[0161] In step S1144, the processor 400 determines the third SOC by applying a first weight and a second weight to the first SOC and the second SOC, respectively. The third SOC may be equal to the SOC of the battery bank BB determined in step S944.

[0162] In step S1150, the processor 400 determines that the third SOC is equal to the first SOC.

[0163] In step S1160, the processor 400 applies a second weighted summation operation to the third SOC and the previous SOC of the battery bank BB to determine the SOC of the battery bank BB. Step S1160 may include steps S1162 and S1164.

[0164] In step S1162, the processor 400 determines a third weight and a fourth weight based on the difference between the third SOC and the previous SOC of the battery bank BB. The sum of the third weight and the fourth weight can be equal to a set value.

[0165] In step S1164, the processor 400 determines the SOC of the battery bank BB by applying the third weight and the fourth weight to the third SOC and the previous SOC of the battery bank BB, respectively.

[0166] Figure 11 Steps S1162 and S1164 can be respectively connected with Figure 10 Steps S1062 and S1064 are the same.

[0167] The processor 400 can determine whether to stop charging or discharging the battery bank BB based on the SOC of the battery bank BB determined in steps S240, S940, S1060 or S1160.

[0168] Specifically, when the State of Charge (SOC) of battery bank BB reaches the upper or lower limit of the allowable SOC range or exceeds the allowable SOC range, processor 400 can stop charging or discharging battery bank BB. Therefore, battery packs BG_1 to BG_m of battery bank BB can be protected from overcharging and over-discharging.

[0169] As an example, when the SOC of the battery bank BB reaches the upper limit of the allowable SOC range during charging of the battery bank BB, the processor 400 can send a standby command to the power conversion system 10 or turn off multiple switches 200_1~200_m.

[0170] As another example, when the SOC of the battery bank BB reaches the lower limit of the allowable SOC range during the discharge of the battery bank BB, the processor 400 can send a standby command to the power conversion system 10 or turn off multiple switches 200_1 to 200_m.

[0171] The embodiments of this disclosure described above are implemented not only by means of apparatus and methods, but also by means of a program that performs functions corresponding to the exemplary configuration of this disclosure or a recording medium on which such program is recorded, and those skilled in the art can easily implement such implementations based on the disclosure of the previously described embodiments.

[0172] Although this disclosure has been described above with reference to certain embodiments and drawings, it is not limited thereto, and it will be apparent to those skilled in the art that various modifications and changes can be made to the technical aspects of this disclosure and to the scope of the appended claims and their equivalents.

[0173] Furthermore, since many substitutions, modifications and changes can be made to this disclosure by those skilled in the art without departing from the technical aspects of this disclosure, this disclosure is not limited to the above embodiments and drawings, and some or all of these embodiments can be selectively combined to allow for various modifications.

Claims

1. A method for determining the State of Charge (SOC) of a battery bank comprising multiple battery packs, the SOC determination method comprising: The first SOC is determined to be equal to the average SOC of the plurality of battery packs; The SOC determination method further includes: When the first SOC is different from the reference SOC or exceeds the range of the reference SOC Depending on whether the battery bank is being charged or discharged, the second SOC is determined to be equal to either the maximum or minimum SOC of the plurality of battery packs; and The SOC of the battery bank is determined by applying a weighted summation operation to the first SOC and the second SOC.

2. The SOC determination method according to claim 1, in, Determining the SOC of the battery bank includes: The first weight and the second weight are determined based on the second SOC; and The SOC of the battery bank is determined by applying the first weight and the second weight to the first SOC and the second SOC, respectively.

3. The SOC determination method according to claim 2, in, Determining the first weight and the second weight includes: When the battery bank is being charged and the first SOC is greater than the reference SOC or the upper limit of the reference SOC range, The second weight is determined by applying a predetermined positive correspondence to the second SOC; and The first weight is determined to be a value whose sum with the second weight equals a predetermined value.

4. The SOC determination method according to claim 2, in, Determining the first weight and the second weight includes: When the battery bank is being discharged and the first SOC is less than the reference SOC or the lower limit of the reference SOC range, The first weight is determined by applying a predetermined positive correspondence to the second SOC; and The second weight is determined to be a value whose sum with the first weight equals a predetermined value.

5. The SOC determination method according to claim 2, in, Determining the first weight and the second weight includes: When the battery bank is being charged and the first SOC is greater than the reference SOC or the upper limit of the reference SOC range, The first weight is determined by applying a predetermined negative correspondence to the second SOC; and The second weight is determined to be a value whose sum with the first weight equals a predetermined value.

6. The SOC determination method according to claim 2, in, Determining the first weight and the second weight includes: When the battery bank is being discharged and the first SOC is less than the reference SOC or the upper limit of the reference SOC range, The second weight is determined by applying a predetermined negative correspondence to the second SOC; and The first weight is determined to be a value whose sum with the second weight equals a predetermined value.

7. The SOC determination method according to claim 2 further includes: When the first SOC is equal to or falls within the range of the reference SOC, the SOC of the battery bank is determined to be equal to the first SOC.

8. The SOC determination method according to claim 1, in, Determining the second SOC includes: When the battery bank is being charged, it is determined that the second SOC is equal to the maximum SOC, and When the battery bank is being discharged, the second SOC is determined to be equal to the minimum SOC.

9. The SOC determination method according to claim 1, further comprising: When the SOC of the battery bank reaches the upper or lower limit of the allowable SOC range or exceeds the allowable SOC range, charging or discharging of the battery bank shall be stopped.

10. A method for determining the State of Charge (SOC) of a battery bank comprising multiple battery packs, the SOC determination method comprising: The first SOC is determined to be equal to the average SOC of the plurality of battery packs; The SOC determination method further includes: When the first SOC is different from the reference SOC or exceeds the range of the reference SOC Depending on whether the battery bank is being charged or discharged, the second SOC is determined to be equal to the maximum or minimum SOC of the plurality of battery banks; The first weight and the second weight are determined based on the second SOC; The third SOC is determined by applying a first weighted summation operation to the first SOC and the second SOC; and The SOC of the battery bank is determined by applying a second weighted summation operation to the third SOC and the previous SOC of the battery bank.

11. The SOC determination method according to claim 10, further comprising: When the first SOC is equal to the reference SOC or falls within the range of the reference SOC, the third SOC is determined to be equal to the first SOC.

12. The SOC determination method according to claim 10, in, Determining the SOC of the battery bank includes: The third weight and the fourth weight are determined based on the difference between the third SOC and the previous SOC of the battery bank; and The SOC of the battery bank is determined by applying the third weight and the fourth weight to the third SOC and the previous SOC of the battery bank, respectively.

13. A SOC determination apparatus for a battery bank comprising multiple battery packs, the SOC determination apparatus comprising: A processor, configured to determine that a first SOC equals the average SOC of the plurality of battery packs, The processor is configured to perform the following operations: When the first SOC is different from the reference SOC or exceeds the range of the reference SOC Depending on whether the battery bank is being charged or discharged, the second SOC is determined to be equal to either the maximum or minimum SOC of the plurality of battery packs; and The SOC of the battery bank is determined by applying a weighted summation operation to the first SOC and the second SOC.

14. A SOC determination apparatus for a battery bank comprising multiple battery packs, the SOC determination apparatus comprising: A processor, configured to determine that a first SOC equals the average SOC of the plurality of battery packs, The processor is configured to perform the following operations: When the first SOC is different from the reference SOC or exceeds the range of the reference SOC Depending on whether the battery bank is being charged or discharged, the second SOC is determined to be equal to the maximum or minimum SOC of the plurality of battery banks; The third SOC is determined by applying a first weighted summation operation to the first SOC and the second SOC; and The SOC of the battery bank is determined by applying a second weighted summation operation to the third SOC and the previous SOC of the battery bank.

15. A battery system comprising the SOC determination device according to claim 13 or 14.

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