Battery system and method for controlling parallel packs using the same

Abstract

The present invention relates to a battery system and a method for controlling a parallel pack using the same. The battery system includes a plurality of battery packs connected in parallel, a plurality of switches connected in series to one of both ends of each of the plurality of battery packs, a battery monitoring integrated circuit (BMIC) that acquires state information including a plurality of pack voltages for the plurality of battery packs, generates a plurality of candidate groups including at least one battery pack of the plurality of battery packs based on the plurality of pack voltages, estimates the capacity of each of the plurality of battery packs based on the state information, determines one final connection group that performs a power operation among the plurality of candidate groups based on the capacity of each of the plurality of battery packs, and a main control unit (MCU) that transmits a pack control signal to the BMIC to turn on the switches connected to the battery packs belonging to the final connection group among the plurality of switches.

Description

Technical Field

[0001] [Cross - Reference to Related Applications] This application claims the benefit of priority based on Korean Patent Application No. 10 - 2022 - 0147905 filed on November 8, 2022 and Korean Patent Application No. 10 - 2023 - 0073573 filed on June 8, 2023, and all the contents disclosed in the documents of the Korean patent applications are included as part of this specification.

[0002] The present disclosure relates to a battery system and a method for controlling a parallel pack using the same.

Background Art

[0003] In a system where battery packs are connected in parallel, one combination of a plurality of battery packs can be selected and operated in parallel. In order to find such a combination of battery packs operating in parallel, the state of charge (SOC) of each of the plurality of battery packs can be considered.

[0004] However, since it may be difficult to fully represent the performance of a battery pack only by the SOC, there may be cases where a battery device in which battery packs combined considering only the SOC are connected in parallel cannot exhibit optimal performance.

Summary of the Invention

Problems to be Solved by the Invention

[0005] Provided are a battery system and a method for controlling a parallel pack that determine a combination of battery packs to be operated in parallel among a plurality of battery packs included in a battery system including a plurality of battery packs, and connect the determined combination of packs in parallel.

Means for Solving the Problems

[0006] A battery system according to a certain feature of the invention includes a plurality of battery packs connected in parallel, a plurality of switches connected in series to one of both ends of each of the plurality of battery packs, a battery monitoring integrated circuit (BMIC) that acquires state information including a plurality of pack voltages for the plurality of battery packs, generates a plurality of candidate groups including at least one battery pack of the plurality of battery packs based on the plurality of pack voltages, estimates the capacity of each of the plurality of battery packs based on the state information, determines one final connection group that performs a power operation among the plurality of candidate groups based on the capacity of each of the plurality of battery packs, and a main control unit (MCU) that transmits a pack control signal to the BMIC to turn on the switches connected to the battery packs belonging to the final connection group among the plurality of switches.

[0007] The MCU can sort the plurality of battery packs in descending order of pack voltage, and for each of the plurality of battery packs according to the sorting order as a reference pack, determine a group including battery packs having a pack voltage equal to or lower than the pack voltage of the reference pack and having a voltage deviation from the pack voltage of the reference pack equal to or lower than a predetermined reference voltage as the candidate group.

[0008] The MCU can estimate the state of charge (SOC) and state of health (SOH) of each of the plurality of battery packs, and estimate the capacity of each of the plurality of battery packs based on the SOC and SOH of each of the plurality of battery packs.

[0009] The MCU can derive a combined capacity by adding up the capacities of at least one battery pack belonging to each of the plurality of candidate groups based on the capacity of each of the plurality of battery packs.

[0010] The MCU can determine one of the plurality of candidate groups as the final connection group based on the calculated capacity.

[0011] When the BMIC receives the pack control signal from the MCU, it can generate a switch control signal to close at least one first switch connected to at least one battery pack belonging to the final connection group among the plurality of switches, and open the remaining switches except the first switch among the plurality of switches, and transmit the switch control signal to the plurality of switches.

[0012] The MCU can determine available battery packs among the plurality of battery packs, arrange the available battery packs in descending order of pack voltage, use each of the available battery packs as the reference pack according to the arrangement order, and determine a group including battery packs having a pack voltage equal to or lower than the pack voltage of the reference pack and a voltage deviation from the pack voltage of the reference pack being equal to or lower than a predetermined reference voltage as the candidate group.

[0013] The method for controlling the parallel pack according to other features of the invention includes the steps that the battery management system (BMS) receives a signal indicating that the vehicle is in the driving mode from the vehicle control unit (VCU); the BMS groups a plurality of candidate groups, each including at least one battery pack among the plurality of battery packs connected in parallel, based on the pack voltage of each of the plurality of battery packs; the BMS estimates the state of charge (SOC) and the state of health (SOH) of each of the plurality of battery packs, and estimates the capacity of each of the plurality of battery packs based on the SOC and the SOH of each of the plurality of battery packs; and the BMS determines one final connection group among the plurality of candidate groups based on the capacity of each of the plurality of battery packs.

[0014] The step of grouping the plurality of candidate groups may include the steps of arranging the plurality of battery packs in descending order of pack voltage, and determining, as the candidate group, a group including battery packs having a pack voltage lower than that of the reference pack among the plurality of battery packs and having a voltage deviation from the pack voltage of the reference pack within a predetermined reference voltage, with each of the plurality of battery packs serving as the reference pack according to the arrangement order.

[0015] The step of determining one final connection group among the plurality of candidate groups may include the steps of deriving a combined capacity by adding up the capacities of at least one battery pack belonging to each of the plurality of candidate groups based on the capacity of each of the plurality of battery packs, and determining one of the plurality of candidate groups as the final connection group based on the combined capacity.

[0016] The BMS may further include a step of generating a switch control signal for closing a first switch connected to a battery pack belonging to the final connection group among a plurality of switches connected in series to one end of each of the plurality of battery packs, and transmitting the switch control signal to the plurality of switches to open the remaining switches except the first switch among the plurality of switches.

[0017] The step of grouping the plurality of candidate groups may include determining available battery packs among the plurality of battery packs, arranging the available battery packs in descending order of pack voltage, using each of the available battery packs as the reference pack according to the arrangement order, and determining a group including battery packs having a pack voltage equal to or lower than the pack voltage of the reference pack and a voltage deviation from the pack voltage of the reference pack being equal to or lower than a predetermined reference voltage as the candidate group.

Advantages of the Invention

[0018] Determine a combination of packs to be connected in parallel considering the energy amount of each of the plurality of battery packs, so that the battery system including this can have the maximum energy.

[0019] Estimate the capacity of the battery by considering both the SOC and SOH of the combination of packs to be connected in parallel, and thereby determine an optimal combination of packs considering the deviation between SOHs.

[0020] Even if each of the plurality of battery packs deteriorates differently, when a battery system connected in parallel with an optimal combination of packs is connected to a vehicle, the driving distance of the vehicle can be improved.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0022] Hereinafter, with reference to the accompanying drawings, the embodiments disclosed in this specification will be described in detail. However, the same or similar components are assigned the same or similar drawing numbers, and duplicate descriptions thereof are omitted. The suffixes “module” and / or “section” for the components used in the following description are given or mixed only for the ease of preparing the specification, and do not have meanings or roles that are distinguishable from each other by themselves. Also, when it is determined that a specific description of such known technology may obscure the gist of the embodiments disclosed in this specification in explaining the embodiments disclosed in this specification, the detailed description thereof is omitted. Furthermore, the accompanying drawings are only for facilitating the understanding of the embodiments disclosed in this specification, and the technical idea disclosed in this specification is not limited by the accompanying drawings, and it should be understood that all modifications, equivalents, or alternatives included in the idea and technical scope of the present invention are included.

[0023] Terms including ordinal numbers such as first, second, etc. can be used to describe various components, but the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

[0024] In this application, terms such as "comprising" or "having" are intended to specify the presence of the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and it should be understood that they do not preclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0025] In the configuration that controls other configurations under specific control conditions among the configurations according to an embodiment, a program realized by a set of instruction words that embody the control algorithm necessary to control the other configurations may be installed. The control configuration can process input data and stored data by the installed program to generate output data. The control configuration can include a non-volatile memory for storing the program and a memory for storing data.

[0026] FIG. 1 is a diagram showing a battery system according to an embodiment.

[0027] The battery system 1 can include a battery device 100, a battery management system (BMS) 200, relays 300 and 301, and a plurality of switches SW1 - SW5.

[0028] The battery device 100 can include a plurality of battery packs 110, 120, 130, 140, 150 connected in parallel. In FIG. 1, the number of battery packs 110, 120, 130, 140, 150 is shown as five, but the invention is not limited thereto, and the battery system 1 can include three or more battery packs.

[0029] Each of the plurality of battery packs 110, 120, 130, 140, 150 can include a plurality of battery cells. For example, the battery pack 110 can include a plurality of battery cells 111-114 connected in series. In FIG. 1, the number of the plurality of battery cells 111-114 is shown as four, but the invention is not limited thereto. Each of the plurality of battery packs 110, 120, 130, 140, 150 can be realized by two or more battery cells connected in series, two or more battery cells connected in parallel, a plurality of battery cells in which two or more battery cells connected in parallel are connected in series, or two or more battery cells connected in parallel.

[0030] One end of the relays 300, 301 is connected to the battery device 100, and the other end of the relays 300, 301 is connected to at least one configuration in the external device 2. The closing and opening of the relays 300, 301 can be controlled according to the relay control signals RCS1, RCS2 supplied from the BMS 200.

[0031] The battery system 1 can be connected to the external device 2. The external device 2 can include loads such as inverters and converters and charging devices. When the external device 2 is a charger, both ends P+, P- of the battery system 1 can be connected to the charger and charged by receiving power from the charger. When the external device 2 is a load, both ends P+, P- of the battery system 1 can be connected to the load and the power supplied by the battery pack 10 can be discharged through the load.

[0032] The external device 2 can include a vehicle control unit (VCU) 21 contained in the vehicle. The BMS 200 can communicate with the VCU 21 to exchange signals with each other. The VCU 21 can receive a request for an operation mode for the vehicle from the BMS 200. The operation mode can include a plurality of vehicle modes such as a driving mode with the gear position in the "D" range, a parking mode with the gear position in the "D" range and the vehicle stopped, a parking mode with the gear position in the "P" range, and an inspection mode for inspecting the vehicle. When receiving the operation mode request, the VCU 21 can transmit a signal indicating one of the plurality of vehicle modes to the BMS 200 as a response to the request.

[0033] When the operation mode indicated by the signal received by the BMS 200 from the VCU 21 is the driving mode, the BMS 200 can determine a battery pack that performs a power operation among the plurality of battery packs 110, 120, 130, 140, 150, and can turn on the switch connected to the determined battery pack among the plurality of switches SW1 - SW5. Then, the battery pack can be connected to the node N1. The power operation can include a discharging operation for supplying power externally and a charging operation by the power supplied from outside. Here, when there are two or more battery packs among the plurality of battery packs 110, 120, 130, 140, 150 that perform a power operation, the battery packs can be connected in parallel with each other.

[0034] One end of each of the plurality of switches SW1 - SW5 is connected to each other at the node N1, and the other end of each of the plurality of switches SW1 - SW5 may be connected in series to one end of each of the plurality of battery packs 110, 120, 130, 140, 150.

[0035] One end of switch SW1 is connected to relay 300 at node N1, and the other end of switch SW1 is connected to the positive terminal of battery pack 110. One end of switch SW2 is connected to relay 300 at node N1, and the other end of switch SW2 is connected to the positive terminal of battery pack 120. One end of switch SW3 is connected to relay 300 at node N1, and the other end of switch SW3 is connected to the positive terminal of battery pack 130. One end of switch SW4 is connected to relay 300 at node N1, and the other end of switch SW4 is connected to the positive terminal of battery pack 140. One end of switch SW5 is connected to relay 300 at node N1, and the other end of switch SW5 is connected to the positive terminal of battery pack 150.

[0036] BMS200 can include a battery monitoring integrated circuit (BMIC) 210 and a main control unit (MCU) 220.

[0037] BMIC 210 can monitor a plurality of pack voltages for the plurality of battery packs 110, 120, 130, 140, 150. BMIC 210 can receive a plurality of voltage measurement signals VS1-VS5 from one end of each of the plurality of battery packs 110, 120, 130, 140, 150. BMIC 210 can include a plurality of terminals P1_1-P1_5. Each of the plurality of terminals P1_1-P1_5 is connected to one end of each of the plurality of battery packs 110, 120, 130, 140, 150 via the plurality of wirings LN1-LN5 respectively. BMIC 210 can receive the plurality of voltage measurement signals VS1-VS5 via the plurality of terminals P1_1-P1_5.

[0038] The positive terminal of the battery pack 110 is connected to the terminal P1_1 via the wiring LN1, and the BMIC 210 can acquire the voltage measurement signal VS1 measured from the positive terminal of the battery pack 110 via the terminal P1_1. The positive terminal of the battery pack 120 is connected to the terminal P1_2 via the wiring LN2, and the BMIC 210 can acquire the voltage measurement signal VS2 measured from the positive terminal of the battery pack 120 via the terminal P1_2. The positive terminal of the battery pack 130 is connected to the terminal P1_3 via the wiring LN3, and the BMIC 210 can acquire the voltage measurement signal VS3 measured from the positive terminal of the battery pack 130 via the terminal P1_3. The positive terminal of the battery pack 140 is connected to the terminal P1_4 via the wiring LN4, and the BMIC 210 can acquire the voltage measurement signal VS4 measured from the positive terminal of the battery pack 140 via the terminal P1_4. The positive terminal of the battery pack 150 is connected to the terminal P1_5 via the wiring LN5, and the BMIC 210 can acquire the voltage measurement signal VS5 measured from the positive terminal of the battery pack 150 via the terminal P1_5.

[0039] The BMIC 210 can derive the pack voltages of the plurality of battery packs 110, 120, 130, 140, and 150 from the plurality of voltage measurement signals VS1-VS5. When the BMIC 210 receives a request signal from the MCU 220, it can acquire the state information of the plurality of battery packs 110, 120, 130, 140, and 150 according to the request signal and transmit a signal indicating the acquired state information to the MCU 220. The state information of the plurality of battery packs 110, 120, 130, 140, and 150 can include the pack voltage, pack temperature, pack current, etc. of each battery pack. For example, when the BMIC 210 receives a request signal for requesting the battery pack voltage or the battery pack temperature from the MCU 220, it can measure the pack voltage or the pack temperature of each of the plurality of battery packs 110, 120, 130, 140, and 150 and transmit a signal indicating the measured pack voltage or pack temperature to the MCU 220.

[0040] The battery device 100 can further include current sensors 101-105 corresponding to a plurality of battery packs 110, 120, 130, 140, 150 respectively. The current sensors 101-105 can periodically measure the pack current of each of the plurality of battery packs 110, 120, 130, 140, 150 and provide signals (hereinafter, "current measurement signals") CS1-CS5 indicating the current measurement results to the MCU 220. The MCU 220 can receive the plurality of current measurement signals CS1-CS5 from the plurality of current sensors 101-105 and use the received current measurement signals CS1-CS5 for estimating the SOC for each of the plurality of battery packs. For example, when the MCU 220 uses the current integration result, the value indicated by the current measurement signals CS1-CS5 can be integrated to estimate the SOC. Also, the MCU 220 can use the current measurement signals CS1-CS5 received from each of the current sensors 101-105 to calculate the amount of charge charged or discharged to each battery pack in order to estimate the capacity of each of the plurality of battery packs.

[0041] In FIG. 1, it is shown that the plurality of current sensors 101-105 directly provide current measurement signals to the MCU 220, but the invention is not limited thereto. The plurality of current sensors 101-105 can transmit the current measurement signals to the BMIC 210. When the BMIC 210 receives a request signal for requesting the battery pack current from the MCU 220, the BMIC 210 can transmit information regarding the plurality of current measurement signals acquired from the plurality of current sensors to the MCU 220.

[0042] The MCU 220 can generate a plurality of candidate groups based on the pack voltage of each of the plurality of battery packs 110, 120, 130, 140, 150, and determine one group that performs a power operation among the plurality of candidate groups based on the state information of the plurality of battery packs 110, 120, 130, 140, 150. Then, the MCU 220 can transmit a pack control signal to the BMIC 210 to turn on the switch connected to the battery pack belonging to the determined one group among the plurality of switches SW1-SW5.

[0043] The MCU 220 can generate a plurality of candidate groups including at least one battery pack among the plurality of battery packs 110, 120, 130, 140, 150 based on signals indicating a plurality of pack voltages received from the BMIC 210. The MCU 220 can estimate the State Of Charge (SOC) and State Of Health (SOH) of each of the plurality of battery packs 110, 120, 130, 140, 150, and can estimate the capacity of each of the plurality of battery packs 110, 120, 130, 140, 150 based on the estimated SOC and SOH. The MCU 220 can determine one group (hereinafter, "final connection group") that performs a power operation among the plurality of candidate groups based on the capacity of each of at least one battery pack belonging to each of the plurality of candidate groups.

[0044] The SOC for a battery can indicate the remaining capacity charged in the battery and can be utilized as one of the indicators showing the performance of the battery.

[0045] The MCU 220 can estimate the state of charge (SOC) of each battery cell unit included in each of the plurality of battery packs 110, 120, 130, 140, 150, and can estimate the representative value (average value or median value) of the SOC of the battery cells constituting each of the plurality of battery packs 110, 120, 130, 140, 150 as the SOC of the pack. The MCU 220 can estimate the SOC of the cell unit by using a current integration method, a method using a relational function or table of open circuit voltage (OCV) and SOC, or the like. Alternatively, the MCU 220 can estimate the SOC of the pack based on values such as the pack current of each of the plurality of battery packs 110, 120, 130, 140, 150, the cell voltage of the battery cells constituting each of the plurality of battery packs 110, 120, 130, 140, 150, and the cell temperature. Alternatively, the MCU 220 can estimate the SOC of the pack based on an equivalent circuit (model equivalent circuit) that models the electrical characteristics of the battery pack. The model equivalent circuit can include a resistance component and a capacitance component of the cells constituting the battery pack, and a wiring resistance connecting a plurality of cells. The method by which the MCU 220 estimates the SOC for each of the plurality of battery packs 110, 120, 130, 140, 150 may be one of various known methods.

[0046] The state of health (SOH) of a battery can indicate the degree of degradation or remaining life of the battery, and can be utilized as one of the indicators showing the performance of the battery. The SOH indicates the current capacity compared to the initial capacity of each of the battery cells constituting each of the plurality of battery packs 110, 120, 130, 140, 150. Here, the capacity indicates the total amount of charge that can be stored in each cell.

[0047] The MCU 220 can estimate the SOH of battery cell units included in each of the plurality of battery packs 110, 120, 130, 140, 150, and estimate the representative value (average value or median value) of the SOH of the battery cells constituting each of the plurality of battery packs 110, 120, 130, 140, 150 as the SOH of the pack. The MCU 220 can estimate the SOH of each cell unit by using methods such as estimating the SOH of a cell based on the SOC of each battery cell, or measuring the capacity of the cell based on the amount of charge required for charging or discharging. The method by which the MCU 220 estimates the SOH for each of the plurality of battery packs 110, 120, 130, 140, 150 may be one of various known methods.

[0048] The MCU 220 can generate a pack control signal for connecting at least one battery pack belonging to the final connection group, and transmit it to the BMIC 210. Upon receiving the pack control signal, the BMIC 210 can generate a plurality of switch control signals SS1 - SS5 based on the pack control signal, and transmit them to the plurality of switches SW1 - SW5 to control the opening or closing operations of the plurality of switches SW1 - SW5.

[0049] The plurality of switch control signals SS1 - SS5 may be signals for closing the switches corresponding to at least one battery pack belonging to the final connection group among the plurality of switches SW1 - SW5, and opening the remaining switches. For example, when the battery packs belonging to the final connection group are the battery pack 140 and the battery pack 150, the switch control signals SS4, SS5 are on - level signals, and the switch control signals SS1 - SS3 are off - level signals.

[0050] A plurality of switches SW1 - SW5 can perform a switching operation according to a plurality of switch control signals SS1 - SS5. A switch that receives an on - level switch control signal may be closed, and a switch that receives an off - level switch control signal may be opened. For example, switches SW4 and SW5 that receive on - level switch control signals SS4 and SS5 may be closed.

[0051] Figure 2 is a detailed configuration diagram of the MCU shown in Figure 1.

[0052] MCU220 can include a communication unit 221, a connection pack determination unit 222, and a control unit 223.

[0053] The communication unit 221 can communicate with the VCU21 to transmit and receive information. The control unit 223 can control the communication unit 221 to transmit an operation mode request to the VCU21. The communication unit 221 can transmit the signal received from the VCU21 to the control unit 223. In this way, the control unit 223 can transmit an operation mode request to the VCU21 via the communication unit 221 and receive a signal indicating one of a plurality of vehicle modes from the VCU21. The VCU21 can generate a signal indicating the operation mode of the vehicle based on any point in time during the period from the time when it receives an operation mode request from the BMS200 to the time when it generates a signal indicating one of a plurality of vehicle modes to the BMS200.

[0054] When the control unit 223 receives a signal indicating a driving mode, it can instruct the connection pack determination unit 222 to determine the final connection group among a plurality of battery packs 110, 120, 130, 140, 150. The connection pack determination unit 222 can perform an operation (hereinafter, connection group determination operation) for determining the final connection group among a plurality of battery packs 110, 120, 130, 140, 150 according to the instruction.

[0055] The control unit 223 generates a pack control signal for controlling to close a switch connected to at least one battery pack belonging to the final connection group determined by the connection pack determination unit 222 among the plurality of switches SW1 - SW5, and can transmit the pack control signal to the BMIC 210 via the communication unit 221.

[0056] Hereinafter, with reference to FIGS. 3 and 4, the specific operations of the communication unit 221, the connection pack determination unit 222, and the control unit 223 will be described.

[0057] FIG. 3 is a flowchart of a method for controlling parallel packs according to an embodiment.

[0058] The communication unit 221 can receive a signal instructing that the vehicle is in the driving mode from the VCU 21 (S1). The communication unit 221 can transmit the signal received from the VCU 21 to the control unit 223. When the control unit 223 receives a signal instructing that it is in the driving mode as a response to the operation mode request, it can instruct the connection pack determination unit 222 to determine the final connection group among the plurality of battery packs 110, 120, 130, 140, 150. The connection pack determination unit 222 can perform a connection group determination operation according to the instruction.

[0059] The connection pack determination unit 222 can determine the available packs among the plurality of battery packs 110, 120, 130, 140, 150 (S2). Here, the available packs may be the battery packs excluding the defective packs among the plurality of battery packs 110, 120, 130, 140, 150.

[0060] The defective pack can indicate a pack among the plurality of battery packs 110, 120, 130, 140, 150 in which a failure has occurred in the battery pack and it is difficult to perform a discharging operation and / or a charging operation.

[0061] The connection pack determination unit 222 can derive the pack voltage of each of the plurality of battery packs 110, 120, 130, 140, 150 based on the signals received from each of the plurality of battery packs 110, 120, 130, 140, 150, and can derive the pack temperature and / or pack current of each of the plurality of battery packs 110, 120, 130, 140, 150 based on the signals received from the temperature sensors and / or current sensors provided in each of the plurality of battery packs 110, 120, 130, 140, 150. The connection pack determination unit 222 can determine a battery pack in which at least one of the pack voltage, pack temperature, and pack current of each of the plurality of battery packs 110, 120, 130, 140, 150 exceeds a predetermined normal range as a defective pack.

[0062] At the time of booting of the MCU 220, the connection pack determination unit 222 can determine a problematic battery pack among the plurality of battery packs 110, 120, 130, 140, 150 as a defective pack by ROM (Read Only Memory) diagnosis.

[0063] Hereinafter, in FIG. 1, the plurality of battery packs 110, 120, 130, 140, 150 will be described on the assumption that all are usable packs.

[0064] The connection pack determination unit 222 can group a plurality of candidate groups including packs having a pack voltage equal to or lower than the pack voltage of a reference pack and having a voltage deviation equal to or lower than a predetermined reference voltage, with each of the usable battery packs as a reference pack (S3).

[0065] In FIG. 3, it is described that the connection pack determination unit 222 groups a plurality of candidate groups based on usable packs, but the invention is not limited thereto. After the S1 step, the connection pack determination unit 222 may group a plurality of candidate groups including packs having a pack voltage equal to or lower than the pack voltage of a reference pack and having a voltage deviation equal to or lower than a predetermined reference voltage, with each of the plurality of battery packs 110, 120, 130, 140, 150 as a reference pack.

[0066] The BMIC210 can transmit a signal instructing a plurality of pack voltages to the MCU220. The connection pack determination unit 222 can generate a plurality of candidate groups based on a plurality of pack voltages based on the signal received from the BMIC210. Hereinafter, with reference to the example of FIG. 4, the operation of the connection pack determination unit 222 will be described.

[0067] FIG. 4 is a table showing examples of the pack voltage, SOC, and SOH of each of a plurality of battery packs.

[0068] In FIG. 4, "first pack", "second pack", "third pack", "fourth pack", and "fifth pack" can correspond to the battery pack 110, battery pack 120, battery pack 130, battery pack 140, and battery pack 150 of FIG. 1, respectively.

[0069] Referring to FIG. 4, the pack voltage of the battery pack 110 is 360V, the pack voltage of the battery pack 120 is 360V, the pack voltage of the battery pack 130 is 365V, the pack voltage of the battery pack 140 is 380V, and the pack voltage of the battery pack 150 is 390V. Hereinafter, it will be described assuming that a predetermined reference voltage, which is a reference value of the voltage deviation, is 10V.

[0070] The connection pack determination unit 222 arranges a plurality of battery packs 110, 120, 130, 140, 150 in descending order of pack voltage, sets one of the plurality of battery packs 110, 120, 130, 140, 150 as a reference pack according to the arrangement order, and compares the voltage deviation between the pack voltage of the battery pack below the pack voltage of the reference pack and the pack voltage of the reference pack among the plurality of battery packs 110, 120, 130, 140, 150 with a predetermined reference voltage.

[0071] Alternatively, the connection pack determination unit 222 can arrange the available battery packs among the plurality of battery packs 110, 120, 130, 140, 150 in descending order of pack voltage, set one of the available battery packs as a reference pack according to the arrangement order, and compare the voltage deviation between the pack voltage of the battery packs among the available battery packs that are below the pack voltage of the reference pack and the pack voltage of the reference pack with a predetermined reference voltage.

[0072] The connection pack determination unit 222 can arrange the plurality of battery packs 110, 120, 130, 140, 150 in the order of the battery pack 150 with the highest pack voltage, the battery pack 140, the battery pack 130, the battery pack 120, and the battery pack 110. The connection pack determination unit 222 can derive a plurality of candidate groups with the battery packs 150, 140, 130, 120, and 110 as reference packs respectively. Since the plurality of candidate groups are derived with the plurality of battery packs 110, 120, 130, 140, 150 as reference packs respectively, the maximum value of the number of candidate groups may be the same as the number of battery packs.

[0073] The connection pack determination unit 222 can use the battery pack 150 as a reference pack and determine the battery pack 140 and the battery pack 150 with a voltage deviation of 10 V or less based on the pack voltage of the battery pack 150 (390 V) as the first group.

[0074] The connection pack determination unit 222 can use the battery pack 140 as a reference pack and determine the battery pack 140 with a voltage deviation of 10 V or less based on the pack voltage of the battery pack 140 (380 V) as the second group.

[0075] The connection pack determination unit 222 can determine the battery packs 110, 120, and 130 with a voltage deviation of 10V or less with respect to the pack voltage (365V) of the battery pack 130 as the reference pack as the third group, with the battery pack 130 as the reference pack.

[0076] The connection pack determination unit 222 can determine the battery packs 110 and 120 with a voltage deviation of 10V or less with respect to the pack voltage (360V) of the battery pack 120 as the reference pack as the fourth group, with the battery pack 120 as the reference pack.

[0077] When the group generated with each reference pack as the reference overlaps with other groups, the connection pack determination unit 222 may use one of the overlapping groups as the candidate group. When the connection pack determination unit 222 uses the battery pack 110 as the reference pack, the fifth group including the battery packs 110 and 120 with a voltage deviation of 10V or less with respect to the pack voltage (360V) of the battery pack 110 overlaps with the fourth group. Therefore, the connection pack determination unit 222 can determine the first to fourth groups excluding the fifth group as the candidate groups.

[0078] The connection pack determination unit 222 can estimate the capacity of each of the plurality of battery packs 110, 120, 130, 140, and 150 (S4). The connection pack determination unit 222 can estimate the SOC and SOH of each of the plurality of battery packs 110, 120, 130, 140, and 150, and can estimate the capacity of each of the plurality of battery packs 110, 120, 130, 140, and 150 based on the initial capacity, SOC, and SOH values of the battery packs.

[0079] The connection pack determination unit 222 can estimate the state of charge (SOC) of each of the plurality of battery packs 110, 120, 130, 140, 150. Referring to FIG. 4, the connection pack determination unit 222 can estimate the SOC of the battery packs 110, 120, 130, 140, 150 to be 70%, 70%, 75%, 85%, and 90% respectively.

[0080] The connection pack determination unit 222 can estimate the state of health (SOH) of each of the plurality of battery packs 110, 120, 130, 140, 150. Referring to FIG. 4, the connection pack determination unit 222 can estimate the SOH of the battery packs 110, 120, 130, 140, 150 to be 80%, 70%, 70%, 95%, and 95% respectively.

[0081] The connection pack determination unit 222 can estimate the initial capacity of each of the plurality of battery packs 110, 120, 130, 140, 150 based on the initial capacity of the battery cells that make up each of the plurality of battery packs 110, 120, 130, 140, 150. Hereinafter, for the sake of convenience of explanation, it will be assumed that the initial capacity of each of the plurality of battery packs 110, 120, 130, 140, 150 is 50 Ah for explanation.

[0082] The connection pack determination unit 222 can estimate the capacity of each of the plurality of battery packs 110, 120, 130, 140, 150 based on the initial capacity, SOC, and SOH values of each of the plurality of battery packs 110, 120, 130, 140, 150. The connection pack determination unit 222 can multiply all of the initial capacity, SOC value, and SOH value of each of the plurality of battery packs 110, 120, 130, 140, 150 to estimate the capacity of each of the plurality of battery packs 110, 120, 130, 140, 150.

[0083] Referring to FIG. 4, the capacity of battery pack 110 is 50 Ah * 0.7 * 0.8 = 28 Ah, the capacity of battery pack 120 is 50 Ah * 0.7 * 0.7 = 24.5 Ah, the capacity of battery pack 130 is 50 Ah * 0.75 * 0.7 = 26.2 Ah, the capacity of battery pack 140 is 50 Ah * 0.85 * 0.95 = 40.3 Ah, and the capacity of battery pack 150 is 50 Ah * 0.9 * 0.95 = 42.7 Ah.

[0084] Based on the capacities of the plurality of battery packs 110, 120, 130, 140, and 150, the connection pack determination unit 222 can determine one of the plurality of candidate groups as the final connection group (S5). The connection pack determination unit 222 can sum the capacities of at least one battery pack belonging to each of the plurality of candidate groups and determine the candidate group having the largest value among the summed capacities as the final connection group.

[0085] Referring to FIG. 4, the summed capacity of the first group including battery pack 140 and battery pack 150 is 40.3 Ah + 42.7 Ah = 83.0 Ah. The summed capacity of the second group including battery pack 140 is 40.3 Ah. The summed capacity of the third group including battery pack 110, battery pack 120, and battery pack 130 is 28 Ah + 24.5 Ah + 26.2 Ah = 78.7 Ah. The summed capacity of the fourth group including battery pack 110 and battery pack 120 is 28 Ah + 24.5 Ah = 52.5 Ah.

[0086] The connection pack determination unit 222 can determine the first group having the largest value (83.0 Ah) among the summed capacities of the plurality of battery packs 110, 120, 130, 140, and 150 as the final connection group. Therefore, the battery packs connected to node N1 among the plurality of battery packs 110, 120, 130, 140, and 150 are battery pack 140 and battery pack 150 belonging to the first group.

[0087] When the connection pack determination unit 222 determines the final connection group, the control unit 223 can generate a pack control signal to cause at least one battery pack belonging to the final connection group to perform a power operation. Referring to FIG. 4, the pack control signal can include signals to cause the battery pack 140 and the battery pack 150 to perform a power operation. The communication unit 221 transmits the pack control signal to the BMIC 210, and the BMS 200 can control the switches corresponding to the battery packs belonging to the final connection group via the BMIC 210 (S6).

[0088] The BMIC 210 can control the switching operations of the plurality of switches SW1 - SW5 based on the pack control signal. The BMIC 210 that has received the pack control signal can generate a plurality of switch control signals SS1 - SS5 to close the switches corresponding to at least one battery pack belonging to the final connection group among the plurality of switches SW1 - SW5 and open the remaining switches. For example, when the battery packs belonging to the final connection group are the battery pack 140 and the battery pack 150 respectively, the switch control signals SS4 and SS5 corresponding to them can be at the on level, and the switch control signals SS1 - SS3 can be at the off level. The BMIC 210 can transmit the plurality of switch control signals SS1 - SS5 to the plurality of switches SW1 - SW5.

[0089] Among the plurality of switches SW1 - SW5, the switches that receive the control signal at the on level can be closed, and the switches that receive the switch control signal at the off level can be opened. For example, the switches SW4 and SW5 that receive the on - level switch control signals SS4 and SS5 can be closed, and the switches SW1, SW2, and SW3 that receive the off - level switch control signals SS1 - SS3 can be opened.

[0090] FIG. 5 is an exemplary diagram for explaining the battery device with the switch closed.

[0091] Referring to FIG. 5, among the plurality of battery packs 110, 120, 130, 140, 150 belonging to the battery device 100 of FIG. 1, the switch SW4 and the switch SW5 may be closed, and the switches SW1, SW2, and SW3 may be open. By the switching operations of the plurality of switches SW1-SW5, the battery pack 140 and the battery pack 150 among the plurality of battery packs 110, 120, 130, 140, 150 can perform a power operation.

[0092] In one embodiment, for each of the plurality of battery packs 110, 120, 130, 140, 150, not only the SOC but also the capacity considering the SOH can be estimated, and the battery packs to be connected in parallel to the battery system 1 can be determined based on the estimated capacity. The capacity considering the SOC and the SOH enables the estimation of the actual energy amount of the battery pack, so that the battery device 100 in which a combination of packs considering the actual energy amount among the plurality of battery packs 110, 120, 130, 140, 150 is connected in parallel can have optimal performance.

[0093] As described above, the embodiments of the present invention have been described in detail, but the scope of the rights of the present invention is not limited thereto, and forms variously modified and improved by those having ordinary knowledge in the field to which the present invention pertains also belong to the scope of the rights of the present invention.

Claims

1. A plurality of battery packs connected in parallel, For each of the plurality of battery packs, a plurality of switches connected in series to one of both ends of each battery pack, A battery monitoring integrated circuit (BMIC) that acquires state information including a plurality of pack voltages for the plurality of battery packs, Based on the plurality of pack voltages, generate a plurality of candidate groups including at least one battery pack of the plurality of battery packs, estimate the capacity of each of the plurality of battery packs based on the state information, and based on the capacity of each of the plurality of battery packs, determine one final connection group that performs a power operation among the plurality of candidate groups, and transmit a pack control signal to the BMIC to turn on the switches connected to the battery packs belonging to the final connection group among the plurality of switches A main control unit (MCU), A battery system including.

2. The MCU is Arrange the plurality of battery packs in descending order of pack voltage, and for each of the plurality of battery packs according to the arrangement order, use each of the plurality of battery packs as a reference pack, and have a pack voltage equal to or lower than the pack voltage of the reference pack among the plurality of battery packs, and the voltage deviation from the pack voltage of the reference pack is within a predetermined reference voltage Determine the group including the battery packs as the plurality of candidate groups, The battery system according to claim 1.

3. The MCU is Estimate the state of charge (SOC) and state of health (SOH) of each of the plurality of battery packs, and estimate the capacity of each of the plurality of battery packs based on the SOC and SOH of each of the plurality of battery packs, The battery system according to claim 2.

4. The MCU is Deriving a combined capacity by adding up the capacities of at least one battery pack belonging to each of the plurality of candidate groups based on the capacity of each of the plurality of battery packs. The battery system according to claim 3.

5. The MCU Determining one of the plurality of final connection groups among the plurality of candidate groups based on the combined capacity. The battery system according to claim 4.

6. The BMIC When receiving the pack control signal from the MCU, closing at least one first switch connected to a battery pack belonging to the final connection group among the plurality of switches, and generating a switch control signal to open the remaining switches among the plurality of switches except the first switch, and transmitting the switch control signal to the plurality of switches. The battery system according to claim 5.

7. The MCU Determining available battery packs among the plurality of battery packs, arranging the available battery packs in descending order of pack voltage, setting each of the available battery packs as a reference pack according to the arrangement order, and determining a group including battery packs having a pack voltage equal to or lower than the pack voltage of the reference pack and having a voltage deviation from the pack voltage of the reference pack within a predetermined reference voltage as the plurality of candidate groups. The battery system according to claim 1.

8. A battery management system (BMS) receiving a signal instructing that the vehicle is in a driving mode from a vehicle control unit; The BMS grouping a plurality of candidate groups each including at least one battery pack among the plurality of battery packs based on the pack voltage of each of the plurality of battery packs connected in parallel; The BMS estimates the SOC of each of the plurality of battery packs and the SOH of the pack, and estimates the capacity of each of the plurality of battery packs based on the SOC of the pack and the SOH of the pack of each of the plurality of battery packs; The BMS determines one final connection group among the plurality of candidate groups based on the capacity of each of the plurality of battery packs; A method for controlling parallel packs including the above.

9. The step of grouping the plurality of candidate groups includes: Arranging the plurality of battery packs in descending order of pack voltage; According to the arrangement order, using each of the plurality of battery packs as a reference pack, determining a group including battery packs having a pack voltage lower than the pack voltage of the reference pack and having a voltage deviation from the pack voltage of the reference pack within a predetermined reference voltage as one of the plurality of candidate groups; The method for controlling parallel packs according to claim 8.

10. The step of determining one final connection group among the plurality of candidate groups includes: Deriving a combined capacity by adding up the capacities of at least one battery pack belonging to each of the plurality of candidate groups based on the capacity of each of the plurality of battery packs; Determining one of the final connection groups among the plurality of candidate groups based on the combined capacity; The method for controlling parallel packs according to claim 9.

11. The BMS further includes generating a switch control signal for closing a first switch connected to a battery pack belonging to the final connection group among a plurality of switches connected in series to one end of both ends of each of the plurality of battery packs and opening the remaining switches except the first switch among the plurality of switches, and transmitting the switch control signal to the plurality of switches. The method for controlling a parallel pack according to claim 9.

12. The step of grouping the plurality of candidate groups is as follows: Determining available battery packs among the plurality of battery packs; Arranging the available battery packs in descending order of pack voltage; Using each of the available battery packs as the reference pack according to the arrangement order, and determining, as the plurality of candidate groups, groups including battery packs that have a pack voltage equal to or lower than the pack voltage of the reference pack and a voltage deviation from the pack voltage of the reference pack that is equal to or lower than a predetermined reference voltage among the available battery packs. The method for controlling a parallel pack according to claim 9.

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