Parallel battery system and method of predicting remaining charge time of parallel battery system

Abstract

In a parallel battery system and a method of predicting a remaining charging time for charging a plurality of battery packs connected in parallel to a final target state of charge (SOC), a battery management system (BMS) estimates an SOC of each of the plurality of battery packs and assigns a ranking number in ascending order; determines a connected group and an available group, the connected group including n (n is a natural number) battery packs among the plurality of battery packs connected to a charging device with a closed relay, the available group including m battery packs not connected to the charging device with a relay open; predicts a first remaining charging time required for a battery pack having a largest ranking number among the n battery packs to reach the final target SOC; calculates a second remaining charging time by adding m predicted remaining charging times of the m battery packs; and predicts a final remaining charging time by adding the first remaining charging time and the second remaining charging time.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2021-0138650, filed on October 18, 2021, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] This invention relates to a parallel battery system and a method for predicting the remaining charging time of the parallel battery system. Background Technology

[0004] Electric vehicles receive power from a battery system, and the battery system includes multiple battery packs. Depending on the electrical power to be supplied to the battery system, the multiple battery packs can be connected in parallel or in series, or battery packs connected in parallel in predetermined units can be connected in series.

[0005] In battery systems with two or more battery packs connected in parallel, there are considerations regarding predicting the remaining charging time compared to battery systems with two or more battery packs connected in series. This is because each of the multiple battery packs connected in parallel involves relay control. An efficient technique is needed to predict the remaining charging time based on the state of each battery pack connected in parallel and the relay control. Summary of the Invention

[0006] Technical issues

[0007] Efforts have been made to make this invention to provide a method for efficiently predicting remaining charging time in a battery system in which two or more battery packs are connected in parallel, based on the state of each of the parallel-connected battery packs and relay control.

[0008] Technical solution

[0009] An exemplary embodiment of the present invention provides a method for predicting the remaining charging time for charging multiple battery packs connected in parallel to a final target state of charge (SOC). The method includes: estimating the SOC of each of the multiple battery packs by a battery management system (BMS); assigning sort numbers to the multiple battery packs by the BMS in ascending order of SOC; determining a connected group group and an available group group by the BMS, the connected group group including battery packs connected to a charging device by a closed relay, the available group group including battery packs not connected to the charging device when the relay is open; predicting by the BMS a first remaining charging time required for the battery pack with the highest sort number among the n battery packs constituting the connected group group to reach the final target SOC; predicting by the BMS m remaining charging times for the m battery packs constituting the available group group, and calculating a second remaining charging time by adding the m remaining charging times; and predicting by the BMS a final remaining charging time by adding the first remaining charging time and the second remaining charging time, wherein n and m are natural numbers.

[0010] Estimating the SOC of each of the multiple battery packs may include: the SOC of each of the multiple battery packs is estimated by the BMS based on the following: the cell voltage of each of the multiple battery cells received from the battery monitoring integrated circuit (BMIC) included in each of the multiple battery packs, the battery current of the multiple battery packs, and the temperature information of the multiple battery packs.

[0011] Determining the connection group and available group may include: the BMS identifying battery packs with an estimated SOC value that is less than a reference SOC value as the connection group.

[0012] Determining the connection group and the available group may include: the BMS identifying battery packs among multiple battery packs that have an estimated SOC value equal to or greater than a reference SOC value as the available group.

[0013] Calculating the second remaining charging time may include: the BMS predicting the remaining charging time of the first battery pack out of m battery packs, excluding the battery pack with the largest sort number, as the charging time required for the estimated SOC of each of the first battery packs to reach the estimated SOC of the second battery pack corresponding to the next sort number.

[0014] Calculating the second remaining charging time may include: the BMS predicting the remaining charging time of the third battery pack with the highest sort number among the m battery packs as the charging time required for the estimated SOC of the third battery pack to reach the final target SOC.

[0015] Another exemplary embodiment of the present invention provides a battery system comprising: a plurality of battery packs connected in parallel; and a battery management system (BMS) that: estimates the state of charge (SOC) value of each of the plurality of battery packs; assigns a sorting number to the plurality of battery packs in ascending order of SOC; determines a connected group and an available group by the BMS, the connected group including battery packs connected to a charging device by a closed relay, the available group including battery packs not connected to the charging device when the relay is open; predicts a first remaining charging time for the connected group and calculates a second remaining charging time for the available group; and predicts a final remaining charging time for charging the plurality of battery packs to a final target SOC by adding the first remaining charging time and the second remaining charging time.

[0016] The BMS can estimate the SOC of each of the multiple battery packs based on the following: the cell voltage of each of the multiple battery cells received from the battery monitoring integrated circuit (BMIC) included in each of the multiple battery packs, the battery current of the multiple battery packs, and the temperature information of the multiple battery packs.

[0017] The BMS can set up a connection group for battery packs that have an estimated SOC value that is lower than the reference SOC value.

[0018] The BMS can set up an available group of battery packs that have an estimated SOC value equal to or greater than a reference SOC value.

[0019] BMS can predict the time required for the battery pack with the highest sort number among the n battery packs that make up the connection group to reach the final target SOC as the first remaining charging time, where n is a natural number.

[0020] BMS can predict the remaining charging time of m battery packs that make up the available group, and calculate the second remaining charging time by adding the m remaining charging times together, where m is a natural number.

[0021] BMS can predict the remaining charging time of the first battery pack, excluding the battery pack with the highest sort number, as the estimated charging time required for the estimated SOC of the first battery pack to reach the estimated SOC of the second battery pack corresponding to the next sort number.

[0022] The BMS can predict the remaining charging time of the third battery pack with the highest sort number among m battery packs as the charging time required for the estimated SOC of the third battery pack to reach the final target SOC, and calculate the second remaining charging time by adding the remaining charging time of the first battery pack and the remaining charging time of the third battery pack.

[0023] Beneficial effects

[0024] In a battery system in which two or more battery packs are connected in parallel, the remaining charging time can be effectively predicted by providing an efficient method for predicting the remaining charging time based on the state of each battery pack connected in parallel and relay control. Attached Figure Description

[0025] Figure 1 This is a diagram illustrating the configuration of a battery system and an external device connected to the battery system according to an exemplary embodiment.

[0026] Figure 2 This is a flowchart illustrating a method for predicting remaining charging time according to an exemplary embodiment.

[0027] Figure 3 This is a schematic diagram illustrating multiple battery packs and the state of charge of each battery pack for illustrative purposes. Figure 2 A diagram illustrating a method for predicting remaining charging time.

[0028] Figure 4 This is a flowchart illustrating a method for predicting remaining charging time according to an exemplary embodiment. Detailed Implementation

[0029] In the following description, exemplary embodiments of the invention will be described with reference to the accompanying drawings, in which, although the exemplary embodiments differ, similar reference numerals refer to similar elements throughout, and redundant descriptions are omitted. In the following description, the use of suffixes such as "module," "part," or "unit" to refer to elements is merely for the purpose of facilitating the description of the invention and has no significant meaning in itself. In describing the invention, detailed descriptions of related known functions or structures have been omitted if they are deemed unnecessary to depart from the essence of the invention, but will be understood by those skilled in the art. The accompanying drawings are intended to facilitate the understanding of the invention and should not be construed as limiting it to the drawings. Similarly, the invention is not limited to the particular form of disclosure without departing from the scope and spirit of the invention, but includes all modifications, equivalents, and substitutions.

[0030] It should be understood that although the terms first, second, etc., may be used in this document to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another.

[0031] It should be further understood that the terms "comprising" or "having" as used in this specification specify the presence of the stated features, steps, operations, components, parts or combinations thereof, but do not exclude the presence or addition of one or more other features, reference numerals, steps, operations, components, parts or combinations thereof.

[0032] A program, implemented as an instruction set of a control algorithm necessary for controlling another configuration, can be installed according to the configuration of the exemplary embodiment for controlling another configuration under specific control conditions. The control configuration can process input data and store data to generate output data according to the installed program. The control configuration may include non-volatile memory for storing the program and memory for storing the data.

[0033] Figure 1 This is a diagram illustrating the configuration of a battery system and an external device connected to the battery system according to an exemplary embodiment.

[0034] The battery system 1 includes multiple battery packs 10 to 50, a battery management system (BMS) 60, and a main relay 70. Figure 1 The invention is shown to have a number of battery packs 10 to 50, which is five in total, but the invention is not limited thereto, and the battery system 1 may include two or more battery packs. Hereinafter, the battery management system 60 is referred to as a BMS.

[0035] External device 2 may include loads such as inverters and converters, as well as charging devices. One end of the main relay 70 is connected to the battery system 1, while the other end of the main relay 70 is connected to at least one component of external device 2.

[0036] Multiple battery packs 10 to 50 can be connected in parallel with each other, and each of the multiple battery packs 10 to 50 can be connected in parallel with an external device 2 via a main relay 70. Each of the multiple battery packs 10 to 50 includes multiple corresponding battery cells (e.g., 11 to 15) among all battery cells 11 to 15, 21 to 25, 31 to 35, 41 to 45, and 51 to 55, a corresponding relay (e.g., 101) among multiple relays 101, 201, 301, 401, and 501, and a corresponding group battery monitoring integrated circuit (e.g., 102) among multiple group battery monitoring integrated circuits 102, 202, 302, 402, and 502. Hereinafter, the battery monitoring integrated circuit is referred to as a BMIC.

[0037] Multiple groups of BMICs 102 to 502 are connected to multiple battery cells 11 to 15, 21 to 25, 31 to 35, 41 to 45 and 51 to 55, for example 11 to 15, and obtain information about each of the multiple battery cells 11 to 15, 21 to 25, 31 to 35, 41 to 45 and 51 to 55, the battery current of the battery pack 10 to 50, the temperature of the battery pack 10 to 50, etc.

[0038] BMS 60 can control the charging and discharging of multiple battery packs 10 to 50 based on battery pack voltage, battery pack current, battery pack temperature, etc. received from multiple groups of BMICs 102 to 502, and control the single-cell balancing operation of multiple battery cells 11 to 15, 21 to 25, 31 to 35, 41 to 45, and 51 to 55.

[0039] BMS 60 can send control signals for charging / discharging, control signals for controlling cell balancing operations, etc., to multiple groups of BMICs 102 to 502 and the main relay 70. Each of the multiple groups of BMICs 102 to 502 can control the opening and closing of a corresponding relay among multiple relays 101, 201, 301, 401, and 501 based on the corresponding control signal received from BMS 60, and control the cell balancing operation of each of multiple corresponding battery cells among multiple battery cells 11 to 15, 21 to 25, 31 to 35, 41 to 45, and 51 to 55.

[0040] In the following text, reference will be made to Figure 2 The method described is used by BMS 60 to predict the remaining charging time of battery system 1 by receiving battery pack voltage, battery pack current, battery pack temperature, and whether each of the multiple groups of BMICs 102 to 502 is open or closed.

[0041] Figure 2 This is a flowchart illustrating a method for predicting remaining charging time according to an exemplary embodiment.

[0042] BMS 60 estimates the state of charge (SOC) of each of the plurality of battery packs 10 to 50 (S1). BMS 60 can estimate the state of charge and battery degradation of each battery pack 10 to 50 based on the individual cell voltages of each of the plurality of battery cells 11 to 15, 21 to 25, 31 to 35, 41 to 45, and 51 to 55 received from the plurality of battery packs 10 to 502, the battery pack current of the plurality of battery packs 10 to 50, and the battery pack temperature of the plurality of battery packs 10 to 50. In the following text, the state of charge of the battery is referred to as the state of charge (SOC), and the degradation of the battery is referred to as the state of health (SOH).

[0043] BMS 60 can estimate the SOC of each of the multiple battery cells 11 to 15, 21 to 25, 31 to 35, 41 to 45, and 51 to 55 based on information received from multiple groups of BMICs 102 to 502 regarding the cell voltages of multiple battery cells 11 to 15, 21 to 25, 31 to 35, 41 to 45, and 51 to 55, as well as the battery currents and temperatures of multiple battery packs 10 to 50.

[0044] BMS 60 can derive a representative SOC based on the SOC of multiple individual battery cells (e.g., 11 to 15) and estimate it as the SOC of the battery pack (e.g., 10). Methods for deriving the representative SOC include deriving maximum, minimum, average, etc. When the battery pack (e.g., 10) is charged, the maximum value among the SOCs of the multiple battery cells (e.g., 11 to 15) can be the representative SOC. The method for estimating the SOC of each of the multiple battery cells 11 to 15, 21 to 25, 31 to 35, 41 to 45, and 51 to 55 can be one of various known methods, such as current integration methods, SOC estimation methods based on battery equivalent circuit models, and methods combining current integration methods and SOC estimation methods based on equivalent circuit models using Kalman filters.

[0045] BMS 60 sorts the numbers of multiple battery packs, from 10 to 50, in ascending order of SOC (S2).

[0046] Figure 3 This is a schematic diagram illustrating multiple battery packs and the state of charge of each battery pack for illustrative purposes. Figure 2 A diagram illustrating a method for predicting remaining charging time.

[0047] Before sorting, BMS 60 assigns an index number to each of the multiple battery packs 10 to 50 to distinguish them from one another. For example, in Figure 3 In (a), multiple battery packs 10 to 50 are sequentially assigned index numbers 1, 2, 3, 4 and 5 from left to right.

[0048] exist Figure 3 In this context, the estimated SOC across multiple battery packs (10 to 50) can be schematically represented by the width of the shaded area within each battery pack. Figure 3 In (a), the index numbers are arranged in ascending order according to the SOC of multiple battery packs from 10 to 50 as 5, 1, 3, 2 and 4.

[0049] BMS 60 can arrange multiple battery packs 10 to 50 in ascending order of SOC through step S2, and assign sorting numbers to the multiple battery packs 10 to 50. The sorting number is the number assigned to each of the multiple battery packs 10 to 50 when arranging the multiple battery packs 10 to 50 in ascending order of SOC.

[0050] For example, in Figure 3 In (b), when the BMS 60 arranges multiple battery packs 10 to 50 in ascending order of SOC, they are arranged in the order of index numbers 5, 1, 3, 2, and 4. The BMS 60 can sequentially assign sorting numbers to the multiple arranged battery packs 10 to 50. Therefore, the sorting numbers of the multiple battery packs 10 to 50 are numbered sequentially from left to right as 1, 2, 3, 4, and 5. Similarly, in Figure 3 In (b), the index numbers of the multiple battery packs 10 to 50 are 5, 1, 3, 2 and 4 from the left.

[0051] BMS 60 can determine the final target SOC for multiple battery packs from 10 to 50. For example, BMS 60 can determine the final target SOC as 95% of the SOC of a fully charged battery pack.

[0052] BMS 60 can identify a connection group and an availability group, the connection group including a plurality of battery packs 10 to 50 that are connected to the charging device when relays 101 to 501 are closed, and the availability group including battery packs that are not connected to the charging device when relays 101 to 501 are open (S3).

[0053] In the following text, you can refer to Figure 4 Describes the operations of BMS 60 in determining connection groups and available groups.

[0054] Figure 4 This is a flowchart illustrating a method for predicting remaining charging time according to an exemplary embodiment.

[0055] BMS 60 sorts the battery packs 10 to 50 in ascending order of their SOC (S20) and determines whether the SOC of each battery pack 10 to 50 is less than a reference SOC (S31). As a result of the determination in step S31, battery packs with an SOC less than the reference SOC are identified as connected groups (S32). As a result of the determination in step S31, battery packs with an SOC equal to or greater than the reference SOC are identified as available groups (S33). Here, the reference SOC can be predetermined as initial information.

[0056] exist Figure 3In the example, BMS 60 can identify battery packs 50, 10 and 30 with sort numbers 1, 2 and 3 as connected group groups, and battery packs 20 and 40 with sort numbers 4 and 5 as available group groups.

[0057] Relays 501, 101, and 301 constituting the battery packs 50, 10, and 30 of the connected group are controlled to be in a closed state by control signals generated by BMS 60. Relays 201 and 401 constituting the battery packs 20 and 40 of the available group are controlled to be in an open state by control signals generated by BMS 60. Control signals for controlling the opening or closing of the relays are generated in BMS 60 and sent to the corresponding groups BMICs 102 to 502 of the battery packs, and groups BMICs 102 to 502 can generate relay drive control signals according to the control signals and supply the generated drive control signals to each relay 101 to 501.

[0058] To predict the final remaining charging time of battery system 1, BMS 60 derives the remaining charging time of connected groups and the remaining charging time of available groups.

[0059] In the following text, based on Figure 3 The following example illustrates the remaining charging time estimation steps S4 to S6.

[0060] BMS 60 can predict the remaining charging time of connected groups and the remaining charging time of available groups.

[0061] BMS 60 can estimate the remaining charging time of the battery pack cells by dividing the remaining energy of the battery pack by the power that can be supplied from the charging device. The remaining energy of the battery pack is the difference between the energy corresponding to the target SOC and the energy of the battery pack at the current estimated SOC. BMS 60 can store the energy of the battery pack corresponding to each SOC as a table. This is expressed by [Equation 1] below.

[0062] [Equation 1]

[0063] The target SOC for the remaining charging time of each battery pack can be determined differently for BMS 60 to select each battery pack based on whether the group to which each battery pack 10 to 50 belongs is a connected group or an available group.

[0064] BMS 60 predicts the remaining charging time (e.g., c) of the battery pack with the highest sort number among the n battery packs (e.g., 50, 10, and 30) constituting the connected group as the remaining charging time of the connected group (S4). Here, n is a natural number. Figure 3 In the example, n=3.

[0065] BMS 60 can predict the expected time required for the battery pack with the highest SOC in at least one battery pack belonging to the connected group to reach the final target SOC as the remaining charging time of the connected group.

[0066] In other words, BMS 60 assumes that the final target SOC (e.g., SOC 95%) is the target SOC when predicting the remaining charging time of battery packs belonging to the connected group.

[0067] refer to Figure 3 BMS 60 can predict the remaining charging time (c) of the battery pack 30 with the highest SOC among the three battery packs 50, 10 and 30 included in the connection group as the remaining charging time of the connection group.

[0068] Since battery packs 50, 10, and 30 are connected in parallel to the charging device, one-third of the charging power can be supplied to each battery pack. After charging of battery packs 50, 10, and 30 begins, charging can be terminated when any of the battery packs 50, 10, and 30 connected in parallel to the charging device reaches the target SOC. The remaining charging time (c) of battery pack 30 is used as a representative value of the remaining charging time of the connected battery packs because battery pack 30 has the highest SOC before charging, making it likely that battery pack 30 will reach the target SOC first.

[0069] BMS 60 predicts the remaining charging time of the available battery group (S5) by adding the m remaining charging times of each of the m battery packs (e.g., 20 and 40) that make up the available group. Here, m is a natural number. Figure 3 In the example, m=2.

[0070] BMS 60 can predict the remaining charging time of each of at least one battery pack belonging to an available group, and predict the remaining charging time of the available group by summing the predicted remaining charging times.

[0071] refer to Figure 3 BMS 60 can predict the remaining charging time of the available group by adding the remaining charging time (d) of battery pack 20 and the remaining charging time (e) of battery pack 40 included in the available group.

[0072] BMS 60 can predict the remaining charging time (d) required for the estimated SOC of battery pack 20 to reach the estimated SOC (target SOC) of battery pack 40 corresponding to the next sort number. BMS 60 can also predict the remaining charging time (e) required for the estimated SOC of battery pack 40 with the highest sort number in the available group to reach the final target SOC (target SOC).

[0073] In other words, when predicting the remaining charging time of the battery pack with the highest sort number among the battery packs belonging to the available group, BMS 60 assumes the estimated SOC of the battery pack corresponding to the next sort number as the target SOC. Furthermore, when predicting the remaining charging time of the battery pack with the highest sort number among the battery packs belonging to the available group, BMS 60 assumes the final target SOC (e.g., SOC 95%) is the target SOC.

[0074] The sum of the remaining charging times (d, e) of each of the battery packs 20 and 40 that constitute the available group (d+e) is the same as the estimated charging time to reach the final target SOC value based on the estimated SOC value of the battery pack 20 with the smallest sort number among the battery packs 20 and 40 that constitute the available group.

[0075] As described above, in the method for predicting remaining charging time according to the exemplary embodiment, the remaining charging time of the connection groups that can be connected to the charging device—battery packs 50, 10 and 30—and the remaining charging time of the available groups that can be used—battery packs 20 and 40—can be predicted in another way.

[0076] BMS 60 predicts the final remaining charging time by adding the remaining charging time of the connected groups and the remaining charging time of the available groups (S6). The method by which BMS 60 predicts the final remaining charging time of battery system 1 can be expressed by the following Equation 2.

[0077] [Equation 2]

[0078] ConnP's CRT = the last numbered CRT = c

[0079] AvailP's CRT = the sum of AvailP's CRTs = d + e

[0080] CRT = CRT of ConnP + CRT of AvailP = c + d + e

[0081] Here, CRT is the remaining charging time, ConnP is the connected battery group, and AvailP is the available battery group.

[0082] When charging of the battery packs 50, 10 and 30 that constitute the connection group is terminated from the charging device, the BMS 60 may repeat steps S1 to S6 again.

[0083] Although exemplary embodiments of the invention have been described in detail above, the scope of the invention is not limited thereto, and various modifications and improvements made by those skilled in the art to which the invention pertains are also within the scope of the invention.

Claims

1. A method for predicting the remaining charging time for charging multiple battery packs connected in parallel to a final target state of charge (SOC), the method comprising: The SOC of each of the plurality of battery packs is estimated by the BMS; The BMS assigns sorting numbers to the multiple battery packs in ascending order of SOC; The BMS determines the connection group and the availability group. The connection group includes the battery packs among the plurality of battery packs that are connected to the charging device by a closed relay, and the availability group includes the battery packs that are not connected to the charging device when the relay is open. The BMS predicts the first remaining charging time required for the battery pack with the highest sort number among the n battery packs constituting the connection group to reach the final target SOC. The BMS predicts m remaining charging times for m battery packs constituting the available group, and calculates a second remaining charging time by adding the m remaining charging times together. as well as The BMS predicts the final remaining charging time by adding the first remaining charging time and the second remaining charging time. Where n and m are natural numbers.

2. The method according to claim 1, wherein: Estimating the SOC of each of the plurality of battery packs includes: The BMS estimates the SOC of each of the plurality of battery packs based on the following: the cell voltage of each of the plurality of battery cells received from the battery monitoring integrated circuit (BMIC) included in each of the plurality of battery packs, the battery current of the plurality of battery packs, and the temperature information of the plurality of battery packs.

3. The method according to claim 1, wherein: Determining the connection group and the available group includes: The BMS identifies the battery packs among the plurality of battery packs that have an estimated SOC value less than a reference SOC value as the connection group.

4. The method according to claim 1, wherein: Determining the connection group and the available group includes: The BMS identifies the battery packs among the plurality of battery packs that have an estimated SOC value equal to or greater than a reference SOC value as the available group.

5. The method according to claim 1, wherein: The calculation of the second remaining charging time includes: The BMS predicts the remaining charging time of the first battery pack (excluding the battery pack with the highest sort number) among the m battery packs as the charging time required for the estimated SOC of each of the first battery packs to reach the estimated SOC of the second battery pack corresponding to the next sort number.

6. The method according to claim 1, wherein: The calculation of the second remaining charging time includes: The BMS predicts the remaining charging time of the third battery pack with the highest sort number among the m battery packs as the estimated charging time required for the third battery pack to reach the final target SOC.

7. A battery system, comprising: Multiple battery packs, which are connected in parallel; as well as BMS, which estimates the SOC value of each of the plurality of battery packs; The battery packs are assigned sorting numbers in ascending order of SOC; the BMS determines the connection group and the available group, the connection group including the battery packs connected to the charging device by a closed relay, and the available group including the battery packs not connected to the charging device when the relay is open; a first remaining charging time for the connection group is predicted and a second remaining charging time for the available group is calculated; And by adding the first remaining charging time and the second remaining charging time, the final remaining charging time for charging the plurality of battery packs to the final target SOC is predicted.

8. The battery system according to claim 7, wherein: The BMS estimates the SOC of each of the plurality of battery packs based on the following: the cell voltage of each of the plurality of battery cells received from the battery monitoring integrated circuit (BMIC) included in each of the plurality of battery packs, the battery current of the plurality of battery packs, and the temperature information of the plurality of battery packs.

9. The battery system according to claim 7, wherein: The BMS sets the battery packs with estimated SOC values ​​that are less than the reference SOC value into the connection group.

10. The battery system according to claim 7, wherein: The BMS sets the battery packs with an estimated SOC value equal to or greater than the reference SOC value as the available group.

11. The battery system according to claim 7, wherein: The BMS predicts the time required for the battery pack with the highest sort number among the n battery packs constituting the connection group to reach the final target SOC as the first remaining charging time, where n is a natural number.

12. The battery system according to claim 7, wherein: The BMS predicts m remaining charging times for the m battery packs that constitute the available group, and calculates a second remaining charging time by adding the m remaining charging times together, where m is a natural number.

13. The battery system according to claim 12, wherein: The BMS predicts the remaining charging time for the first battery pack, excluding the battery pack with the highest sort number, to reach the estimated SOC of the second battery pack corresponding to the next sort number.

14. The battery system according to claim 13, wherein: The BMS predicts the remaining charging time of the third battery pack with the highest sort number among the m battery packs as the charging time required for the estimated SOC of the third battery pack to reach the final target SOC, and calculates the second remaining charging time by adding the remaining charging time of the first battery pack and the remaining charging time of the third battery pack.

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