Battery system and method for controlling connection between battery packs using the same

Abstract

The present invention relates to a battery system and a method for controlling connection between battery packs using the same, the battery system including a battery device including a plurality of battery packs, first and second terminals connected to both ends of the battery device, and a battery management system (BMS) that derives a plurality of pack voltages for the plurality of battery packs based on a plurality of voltage measurement signals received from the plurality of battery packs, determines the voltage across the battery device as a first voltage or a second voltage depending on which of the first and second terminals is connected to a driving device, determines whether the plurality of battery packs are connected in parallel or in series based on the voltage across the battery device, and, if the plurality of battery packs are connected in series, determines which battery packs of the plurality of battery packs to connect in series based on the plurality of pack voltages.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0186958, filed on December 28, 2022, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

[0002] The present disclosure relates to a battery system and a method for controlling connections between battery packs using the same. [Background technology]

[0003] The external system connected to the battery system may include devices that require a voltage level of 400 V to operate and devices that require a voltage level of 800 V to operate. In order for the battery system to charge and discharge the external system, a pack connection that matches the operating voltage of the devices in the external system is required.

[0004] There is a need for a battery system that can be charged and discharged from a device operating at an 800V voltage level without connecting a battery pack with a 400V pack voltage and a battery pack with an 800V pack voltage. Summary of the Invention [Problem to be solved by the invention]

[0005] A battery system including a plurality of battery packs with a pack voltage corresponding to 400V, in which a series-parallel connection relationship between the plurality of battery packs can be selected and the battery system can be connected to devices with different operating voltages, and a method for controlling the connection between the battery packs using the same is provided. [Means for solving the problem]

[0006] According to one aspect of the present invention, a battery system includes a battery device including a plurality of battery packs; first and second terminals connected to both ends of the battery device; and a battery management system (BMS) that derives a plurality of pack voltages for the plurality of battery packs based on a plurality of voltage measurement signals received from the plurality of battery packs, determines the voltage across the battery device as a first voltage or a second voltage depending on which of the first and second terminals is connected to a driving device, determines whether to connect the plurality of battery packs in parallel or in series based on the voltage across the battery device, and, if the plurality of battery packs are connected in series, determines which battery packs of the plurality of battery packs to connect in series based on the plurality of pack voltages.

[0007] The BMS may communicate with an ECU (Electronic Control Unit) via a CAN and receive information from the ECU indicating the discharge level of the battery device as either the first voltage or the second voltage.

[0008] When a first driving device driven at a voltage level of the first voltage is connected to the first terminal, or when information indicating the discharge level of the battery device as the first voltage is received from the ECU, the BMS may determine the voltage across the battery device as the first voltage and connect both ends of at least one battery pack among the plurality of battery packs to both ends of the battery device.

[0009] When a second driving device driven at a voltage level of the second voltage is connected to the second terminal, or when information indicating the discharge level of the battery device as the second voltage is received from the ECU, the BMS may determine the voltage across the battery device as the second voltage, determine at least one series group including two or more battery packs to be connected in series among the plurality of battery packs, and connect both ends of the at least one series group to both ends of the battery device.

[0010] When the number of the at least one series group is two or more, the BMS may determine the two or more series groups such that a difference between a sum of a plurality of first pack voltages for a plurality of first battery packs belonging to a first series group among the two or more series groups and a sum of a plurality of second pack voltages for a plurality of second battery packs belonging to a second series group among the two or more series groups is equal to or less than a predetermined threshold.

[0011] The BMS may generate switch control signals to connect the battery packs belonging to each of the two or more series groups in series, connect the positive terminal of each of the two or more series groups to the positive terminal of the battery device, and connect the negative terminal of each of the two or more series groups to the negative terminal of the battery device.

[0012] A method for controlling connection between battery packs according to another aspect of the present invention includes the steps of: a battery management system (BMS) connecting a battery device including a plurality of battery packs to an external system via either first or second terminals connected to both ends of the battery device; determining, by the BMS, a voltage across the battery device as a first voltage or a second voltage depending on which of the first and second terminals is connected to a driving device; deriving, by the BMS, a plurality of pack voltages for the plurality of battery packs based on a plurality of voltage measurement signals received from the plurality of battery packs; determining whether to connect the plurality of battery packs in parallel or in series based on the voltages across the battery device; and, if the plurality of battery packs are connected in series, determining which of the plurality of battery packs to connect in series based on the plurality of pack voltages.

[0013] The method may further include a step of the BMS communicating with an ECU (Electronic Control Unit) via a CAN and receiving information indicating a discharge level of the battery device as either the first voltage or the second voltage from the ECU.

[0014] When a first driving device driven at a voltage level of the first voltage is connected to the first terminal, or when information indicating the discharge level of the battery device at the first voltage is received from the ECU, the method may further include determining the voltage across the battery device as the first voltage, and connecting both ends of at least one battery pack among the plurality of battery packs to both ends of the battery device.

[0015] When a second driving device driven at a voltage level of the second voltage is connected to the second terminal, or when information instructing the discharge level of the battery device as the second voltage is received from the ECU, the method may further include the steps of determining a voltage across the battery device as the second voltage, determining at least one series group including two or more battery packs to be connected in series among the plurality of battery packs, and connecting both ends of the at least one series group to both ends of the battery device.

[0016] When the number of the at least one series group is two or more, determining the at least one series group may further include determining the two or more series groups such that a difference between a sum of a plurality of first pack voltages for a plurality of first battery packs belonging to a first series group among the two or more series groups and a sum of a plurality of second pack voltages for a plurality of second battery packs belonging to a second series group among the two or more series groups is equal to or less than a predetermined threshold.

[0017] The BMS may further include generating a switch control signal to serially connect the battery packs belonging to each of the two or more series groups, connect a positive terminal of each of the two or more series groups to a positive terminal of the battery device, and connect a negative terminal of each of the two or more series groups to a negative terminal of the battery device. [Effects of the Invention]

[0018] In one embodiment of the present invention, when a device requiring a voltage level of 400V is connected, multiple battery packs are connected in parallel, and when a device requiring a voltage level of 800V is connected, multiple battery packs are connected in series, thereby enabling efficient operation of the battery system.

[0019] According to one embodiment of the present invention, when the battery system is applied to a commercial vehicle, high output or high capacity can be selected depending on the cargo load and driving distance, and the user can use the battery according to their desired direction.

[0020] According to one embodiment of the present invention, the battery can be charged at a location desired by the user of the battery system without distinguishing between 400V charging and 800V charging.

[0021] According to one embodiment of the present invention, a 400V battery pack can be charged at a charging station that outputs 800V capacity, resulting in a reduced charging rate.

[0022] According to one embodiment of the present invention, an existing 400V battery pack can be converted to 800V and used without the need to separately prepare an 800V battery pack. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a block diagram illustrating a battery system according to an embodiment. [Figure 2] An example of the battery system in Figure 1. [Figure 3] 2 is an example of a battery system including multiple series groups of FIG. 1. [Figure 4] 1 is a flowchart of a method for controlling a connection between battery packs according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] Various embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Identical or similar components will be designated by the same reference numerals, and redundant descriptions will be omitted. The suffixes "module" and / or "section" used in the following description are used solely for ease of description and do not have any distinct meanings or functions. Furthermore, when describing the embodiments disclosed herein, detailed descriptions of related publicly known technologies will be omitted if they are deemed to obscure the gist of the embodiments disclosed herein. Furthermore, the accompanying drawings are intended to facilitate understanding of the embodiments disclosed herein, and the technical concepts disclosed herein should not be limited by the accompanying drawings. It should be understood that the accompanying drawings include all modifications, equivalents, and alternatives within the spirit and scope of the present invention.

[0025] Terms including ordinal numbers such as first, second, etc. may be used to describe various components, but the components are not limited to those terms. The terms are used only to distinguish one component from another.

[0026] In this application, the use of terms such as "comprises" or "having" is intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but is understood not to preclude the possible presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0027] In one embodiment, a component that controls another component under a specific control condition may be installed with an implementation program as a set of commands that embody a control algorithm required to control the other component. The control component may process input data and stored data according to the installed program and generate output data. The control component may include a non-volatile memory that stores the program and a memory that stores data.

[0028] FIG. 1 is a block diagram illustrating a battery system according to an embodiment.

[0029] Referring to FIG. 1, a battery system 1 may include a battery device 100, a Battery Management System (BMS) 200, and a plurality of relays 311, 312, 321, and 322.

[0030] The battery device 100 may include a plurality of battery packs 101 to 104 and a plurality of switching elements S1_P, S1_N, S2_P, S2_N, S3_P, S3_N, S4_P, S4_N, S1_2, S1_3, S1_4, S2_3, S2_4, and S3_4. For ease of explanation, of the multiple switching elements S1_P, S1_N, S2_P, S2_N, S3_P, S3_N, S4_P, S4_N, S1_2, S1_3, S1_4, S2_3, S2_4 and S3_4, switching elements S1_P to S4_P will be referred to as positive switching elements, switching elements S1_N to S4_N will be referred to as negative switching elements, and switching elements S1_2, S1_3, S1_4, S2_3, S2_4 and S3_4 will be referred to as series switching elements.

[0031] Each of the plurality of battery packs 101 to 104 may be realized by two or more battery cells connected in series, a plurality of battery cells each having two or more battery cells connected in parallel connected in series, or two or more battery cells connected in parallel.

[0032] Although FIG. 1 illustrates a case where the number of the battery packs 101 to 104 is four, the present invention is not limited to this, and the battery device 100 may include two or more battery packs.

[0033] The BMS 200 may receive multiple voltage measurement signals VS1 to VS8 from the positive and negative electrodes of each of the multiple battery packs 101 to 104. The BMS 200 may acquire a voltage measurement signal VS1 from the positive electrode of the battery pack 101, and the BMS 200 may acquire a voltage measurement signal VS2 from the negative electrode of the battery pack 101. The BMS 200 may acquire a voltage measurement signal VS3 from the positive electrode of the battery pack 102, and the BMS 200 may acquire a voltage measurement signal VS4 from the negative electrode of the battery pack 102. The BMS 200 may acquire a voltage measurement signal VS5 from the positive electrode of the battery pack 103, and the BMS 200 may acquire a voltage measurement signal VS6 from the negative electrode of the battery pack 103. The BMS 200 may acquire a voltage measurement signal VS7 from the positive electrode of the battery pack 104, and the BMS 200 may acquire a voltage measurement signal VS8 from the negative electrode of the battery pack 104.

[0034] The BMS 200 may measure the pack voltages of each of the battery packs 101 to 104 when the positive switching elements S1_P to S4_P and the negative switching elements S1_N to S4_N are in the off state. The BMS 200 may transmit off-level switching control signals SCS1_P to SCS4_P, SCS1_N to SCS4_N to the positive switching elements S1_P to S4_P and the negative switching elements S1_N to S4_N, and receive voltage measurement signals VS1 to VS8.

[0035] The BMS200 may derive the pack voltages of the battery packs 101-104 from the voltage measurement signals VS1-VS8. The BMS200 may derive the pack voltage of the battery pack 101 from the voltage measurement signals VS1 and VS2. The BMS200 may derive the pack voltage of the battery pack 102 from the voltage measurement signals VS3 and VS4. The BMS200 may derive the pack voltage of the battery pack 103 from the voltage measurement signals VS5 and VS6. The BMS200 may derive the pack voltage of the battery pack 104 from the voltage measurement signals VS7 and VS8.

[0036] The BMS 200 may receive battery information indicating the current, voltage, temperature, etc. of the plurality of battery packs 101 to 104 from the battery device 100. The BMS 200 may estimate the pack capacity of each of the plurality of battery packs 101 to 104 based on the battery information.

[0037] One end of the switching element S1_P is connected to the positive terminal of the battery pack 101, and the other end of the switching element S1_P is connected to one end of the relays 311 and 321. One end of the switching element S1_N is connected to the negative terminal of the battery pack 101, and the other end of the switching element S1_N is connected to one end of the relays 312 and 322.

[0038] One end of the switching element S2_P is connected to the positive terminal of the battery pack 102, and the other end of the switching element S2_P is connected to one end of the relays 311 and 321. One end of the switching element S2_N is connected to the negative terminal of the battery pack 102, and the other end of the switching element S2_N is connected to one end of the relays 312 and 322.

[0039] One end of the switching element S3_P is connected to the positive terminal of the battery pack 103, and the other end of the switching element S3_P is connected to one end of the relays 311 and 321. One end of the switching element S3_N is connected to the negative terminal of the battery pack 103, and the other end of the switching element S3_N is connected to one end of the relays 312 and 322.

[0040] One end of the switching element S4_P is connected to the positive terminal of the battery pack 104, and the other end of the switching element S4_P is connected to one end of the relays 311 and 321. One end of the switching element S4_N is connected to the negative terminal of the battery pack 104, and the other end of the switching element S4_N is connected to one end of the relays 312 and 322.

[0041] When the plurality of positive switching elements S1_P to S4_P and the plurality of negative switching elements S1_N to S4_N are in the ON state, the plurality of battery packs 101 to 104 may be connected in parallel.

[0042] The plurality of series switching elements S1_2, S1_3, S1_4, S2_3, S2_4, and S3_4 may be connected between any two battery packs that can be connected in series among the plurality of battery packs 101 to 104. For example, if the battery device 100 includes three battery packs, the plurality of series switching elements may be located between the positive electrode of the first battery pack and the negative electrode of the second battery pack, between the positive electrode of the second battery pack and the negative electrode of the third battery pack, and between the positive electrode of the first battery pack and the negative electrode of the third battery pack.

[0043] One end of the switching element S1_2 is connected to the negative electrode of the battery pack 101, and the other end of the switching element S1_2 is connected to the positive electrode of the battery pack 102. When the switching element S1_2 is in an on state, the battery pack 101 and the battery pack 102 may be connected in series.

[0044] One end of the switching element S1_3 is connected to the negative electrode of the battery pack 101, and the other end of the switching element S1_3 is connected to the positive electrode of the battery pack 103. When the switching element S1_3 is in an on state, the battery pack 101 and the battery pack 103 may be connected in series.

[0045] One end of the switching element S1_4 is connected to the negative electrode of the battery pack 101, and the other end of the switching element S1_4 is connected to the positive electrode of the battery pack 104. When the switching element S1_4 is in an on state, the battery pack 101 and the battery pack 104 may be connected in series.

[0046] One end of the switching element S2_3 is connected to the negative electrode of the battery pack 102, and the other end of the switching element S2_3 is connected to the positive electrode of the battery pack 103. When the switching element S2_3 is in an on state, the battery pack 102 and the battery pack 103 may be connected in series.

[0047] One end of the switching element S2_4 is connected to the negative electrode of the battery pack 102, and the other end of the switching element S2_4 is connected to the positive electrode of the battery pack 104. When the switching element S2_4 is in an on state, the battery pack 102 and the battery pack 104 may be connected in series.

[0048] One end of the switching element S3_4 is connected to the negative electrode of the battery pack 103, and the other end of the switching element S3_4 is connected to the positive electrode of the battery pack 104. When the switching element S3_4 is in an on state, the battery pack 103 and the battery pack 104 may be connected in series.

[0049] When at least one of the plurality of series switching elements S1_2, S1_3, S1_4, S2_3, S2_4, and S3_4 is in an ON state, the corresponding battery packs of the plurality of battery packs 101 to 104 may be connected in series.

[0050] The closing and opening of the multiple switching elements S1_P to S4_P, S1_N to S4_N, S1_2, S1_3, S1_4, S2_3, S2_4 and S3_4 may be controlled by switching control signals SCS1_P to SCS4_P, SCS1_N to SCS4_N, SCS1_2, SCS1_3, SCS1_4, SCS2_3, SCS2_4 and SCS3_4 supplied from BMS200.

[0051] One end of each of the plurality of relays 311, 312, 321, and 322 is connected to the battery device 100, and the other end of each of the plurality of relays 311, 312, 321, and 322 is connected to at least one component in an external system. The closing and opening of the plurality of relays 311, 312, 321, and 322 may be controlled by relay control signals RCS11, RCS12, RCS21, and RCS22 supplied from the BMS 200.

[0052] The battery system 1 may be coupled to an external system, which may be a first drive device 21 or a second drive device 22.

[0053] The power supply voltage level required for operation of the first driver 21 may be the voltage level of the first voltage V1. The power supply voltage level required for operation of the second driver 22 may be the voltage level of the second voltage V2. The second voltage V2 may be at a higher level than the first voltage V1. For example, the first voltage V1 may be 400V and the second voltage V2 may be 800V.

[0054] The pack voltage of each of the plurality of battery packs 101 to 104 may be at a voltage level within a predetermined range with respect to the first voltage V1.

[0055] Each of the first drive device 21 and the second drive device 22 may include at least one of a load, such as an inverter or a converter, and a power conversion device coupled to a charger. While Fig. 1 illustrates one each of the first and second drive devices 21 and 22, the present invention is not limited thereto. The first and second drive devices 21 and 22 may be one or more drive devices.

[0056] When the relay 311 and the relay 312 are in the ON state, the battery system 1 may be coupled to the first driving device 21 via the first terminals P1+ and P1−. While the relay 311 and the relay 312 are in the ON state, the battery system 1 may perform a charging operation or a discharging operation.

[0057] If the first driving device 21 is a power conversion device connected to a charger, the first terminals P1+, P1- of the battery system 1 may be connected to the power conversion device and may be charged by receiving power from the charger while the relays 311 and 312 are on. If the first driving device 21 is a load, the first terminals P1+, P1- of the battery system 1 may be connected to the load while the relays 311 and 312 are on, and power supplied by at least one of the plurality of battery packs 101 to 104 may be discharged through the load.

[0058] When the relays 321 and 322 are in the ON state, the battery system 1 may be coupled to the second driving device 22 via the second terminals P2+ and P2−. While the relays 321 and 322 are in the ON state, the battery system 1 may perform a charging operation or a discharging operation.

[0059] If the second driving device 22 is a power conversion device connected to a charger, the second terminals P2+, P2- of the battery system 1 may be connected to the power conversion device and may be charged by receiving power from the charger while the relays 321 and 322 are on. If the second driving device 22 is a load, the second terminals P2+, P2- of the battery system 1 may be connected to the load while the relays 321 and 322 are on, and power supplied by at least one of the plurality of battery packs 101 to 104 may be discharged via the load.

[0060] A device that controls the operation of the vehicle, for example, an ECU (Electronic Control Unit) 3, may receive a battery state signal (BSS) transmitted from the BMS 200 and transmit information input by a vehicle user to the BMS 200. At this time, the ECU 3 and the BMS 200 may transmit and receive necessary information via CAN communication. The information input by the vehicle user may include a signal indicating the discharge level of the battery device 100 as either a first voltage V1 or a second voltage V2, depending on the user's selection.

[0061] The BMS 200 may store in advance information indicating the rated voltage of the first terminals P1+, P1- to which the first drive unit 21 is connected and the rated voltage of the second terminals P2+, P2- to which the second drive unit 22 is connected. Alternatively, the BMS 200 may receive information indicating the rated voltage of the first terminals P1+, P1- and the rated voltage of the second terminals P2+, P2- from the vehicle's ECU 3. The BMS 200 may receive information from the ECU 3 regarding whether a drive unit is connected to each of the first terminals P1+, P1- and the second terminals P2+, P2-. Alternatively, the BMS 200 may be electrically connected to each of the first terminals P1+, P1- and the second terminals P2+, P2- and detect that a drive unit is connected to each terminal. The BMS 200 may be implemented in various ways to sense whether a driver is connected to each terminal, and if necessary, a separate circuit may be provided to determine whether a driver is connected to each terminal.

[0062] The BMS 200 can determine to connect at least one of the first driving device 21 and the second driving device 22 to the battery system 1. When it is determined to connect the first driving device 21, the BMS 200 may generate relay control signals RCS11 and RCS12 at an on level and transmit them to the relays 311 and 312. When it is determined to connect the second driving device 22, the BMS 200 may generate relay control signals RCS21 and RCS22 at an on level and transmit them to the relays 321 and 322.

[0063] The BMS 200 determines the voltages of both ends P100+, P100- of the battery device 100 according to the driving device connected to the battery device 100, either the first driving device 21 or the second driving device 22, and when the determined voltage of both ends is the second voltage V2, determines which battery packs to connect in series among the plurality of battery packs 101-104 and determines whether to connect the battery packs connected in series in parallel. Hereinafter, for convenience of explanation, the battery packs that the BMS 200 determines to connect in series among the plurality of battery packs corresponding to the second voltage V2 will be referred to as a series group.

[0064] The BMS 200 may generate switching control signals SCS1_P to SCS4_P, SCS1_N to SCS4_N, SCS1_2, SCS1_3, SCS1_4, SCS2_3, SCS2_4, and SCS3_4 at an on level or an off level depending on the determined configuration of the battery packs connected in series, to control the operations of the plurality of switching elements S1_P to S4_P, S1_N to S4_N, S1_2, S1_3, S1_4, S2_3, S2_4, and S3_4. Hereinafter, for convenience of explanation, the operation by the BMS 200 to control the switching operations of the plurality of switching elements S1_P to S4_P, S1_N to S4_N, S1_2, S1_3, S1_4, S2_3, S2_4, and S3_4 will be referred to as a "switching control operation."

[0065] The BMS200 may generate a switch control signal SCS1_P and transmit it to the switching element S1_P. The BMS200 may generate a switch control signal SCS2_P and transmit it to the switching element S2_P. The BMS200 may generate a switch control signal SCS3_P and transmit it to the switching element S3_P. The BMS200 may generate a switch control signal SCS4_P and transmit it to the switching element S4_P. The BMS200 may generate a switch control signal SCS1_N and transmit it to the switching element S1_N. The BMS200 may generate a switch control signal SCS2_N and transmit it to the switching element S2_N. The BMS200 may generate a switch control signal SCS3_N and transmit it to the switching element S3_N. The BMS200 may generate a switch control signal SCS4_N and transmit it to the switching element S4_N.

[0066] The BMS200 may generate a switch control signal SCS1_2 and transmit it to the switching element S1_2. The BMS200 may generate a switch control signal SCS1_3 and transmit it to the switching element S1_3. The BMS200 may generate a switch control signal SCS1_4 and transmit it to the switching element S1_4. The BMS200 may generate a switch control signal SCS2_3 and transmit it to the switching element S2_3. The BMS200 may generate a switch control signal SCS2_4 and transmit it to the switching element S2_4. The BMS200 may generate a switch control signal SCS3_4 and transmit it to the switching element S3_4.

[0067] If the first driving device 21 or the second driving device 22 is a power conversion device connected to a charger, the BMS 200 may perform a switching control operation so that the voltage across both ends P100+, P100- of the battery device 100 corresponds to either the first voltage V1 or the second voltage V2, depending on which of the first terminals P1+, P1- and the second terminals P2+, P2- to which the driving device is connected.

[0068] When the first driving device 21 or the second driving device 22 is a load, the BMS 200 may perform a switching control operation so that the voltage across P100+, P100− of the battery device 100 corresponds to either the first voltage V1 or the second voltage V2 based on information received from the ECU 3. For example, a user may select the discharge level of the battery device 100 connected to the vehicle from the first voltage V1 or the second voltage V2, and input the selected information to the ECU 3 via the vehicle. The ECU 3 may receive information from the user indicating that the discharge level of the battery device 100 is the first voltage V1. In this case, the ECU 3 may transmit information indicating that the first voltage V1 has been selected to the BMS 200.

[0069] When the first driving device 21 is connected to the first terminals P1+, P1- and the battery device 100 is performing a charging operation or the discharge level of the battery device 100 selected by the user is the first voltage V1, the BMS 200 may perform a switching control operation so that the voltage across both ends P100+, P100- of the battery device 100 corresponds to the first voltage V1. Alternatively, even when the discharge level of the battery device 100 is not selected, the BMS 200 may perform a switching control operation so that the voltage across both ends P100+, P100- of the battery device 100 corresponds to the first voltage V1.

[0070] When the second driving device 22 is connected to the second terminals P2+, P2- and the battery device 100 is performing a charging operation, or when the discharge level of the battery device 100 selected by the user is the second voltage V2, the BMS 200 may perform a switching control operation so that the voltage across both ends P100+, P100- of the battery device 100 corresponds to the second voltage V2.

[0071] The BMS 200 may control the switching control operations of the plurality of switching elements S1_P to S4_P, S1_N to S4_N, S1_2, S1_3, S1_4, S2_3, S2_4, and S3_4 based on the pack voltages and / or pack capacities of each of the plurality of battery packs 101 to 104. Alternatively, the BMS 200 may control the switching operations of the plurality of switching elements S1_P to S4_P, S1_N to S4_N, S1_2, S1_3, S1_4, S2_3, S2_4, and S3_4 in response to a command input from the ECU 3. For convenience of explanation, the following description will be given assuming that the BMS 200 controls the switching operations of a plurality of switching elements S1_P to S4_P, S1_N to S4_N, S1_2, S1_3, S1_4, S2_3, S2_4, and S3_4 based on the pack voltages of the plurality of battery packs 101 to 104, respectively.

[0072] When the plurality of relays 311, 312 are turned on and the first driving device 21 is connected to the battery device 100, the BMS 200 may determine the voltage across both ends P100+, P100− of the battery device 100 as the first voltage V1. This is because the first voltage V1 corresponds to the power supply level required for the operation of the first driving device 21. Because the pack voltage of each of the plurality of battery packs 101-104 corresponds to the first voltage V1, the BMS 200 may determine at least one battery pack from the plurality of battery packs 101-104 to be connected to both ends P100+, P100− of the battery device 100.

[0073] Hereinafter, with reference to FIG. 2, a switching control operation in which the BMS 200 causes both ends P100+ and P100- of the battery device 100 to correspond to the first voltage V1 will be described.

[0074] FIG. 2 is an example of the battery system of FIG.

[0075] The BMS 200 may determine at least one battery pack among the plurality of battery packs 101-104 to be connected to both ends P100+, P100- of the battery device 100 based on the pack voltages of each of the plurality of battery packs 101-104. The BMS 200 may store a first reference voltage range, which is a normal range of the voltages across P100+, P100- of the battery device 100, corresponding to the first voltage. The BMS 200 may determine at least one battery pack for which the voltages across P100+, P100- of the battery device 100 are within the first reference voltage range.

[0076] The BMS 200 may connect one battery pack to both ends P100+ and P100- of the battery device 100, or may connect two or more battery packs in parallel.

[0077] In the example of FIG. 2, the BMS 200 may connect the battery pack 101, the battery pack 103, and the battery pack 104 among the plurality of battery packs 101 to 104 to both ends P100+ and P100− of the battery device 100.

[0078] The BMS 200 may turn off the plurality of series switching elements S1_2, S1_3, S1_4, S2_3, S2_4, and S3_4, and turn on elements among the plurality of positive pole switching elements S1_P to S4_P and the plurality of negative pole switching elements S1_N to S4_N corresponding to the battery packs connected to both ends P100+ and P100− of the battery device 100. In the example of Fig. 2, the BMS 200 may turn off the plurality of series switching elements S1_2, S1_3, S1_4, S2_3, S2_4, and S3_4, and turn on three positive pole switching elements S1_P, S3_P, S4_P and three negative pole switching elements S1_N, S3_N, S4_N corresponding to the battery packs 101, 103, and 104.

[0079] The BMS 200 may generate on-level switching control signals SCS1_P, SCS3_P, SCS4_P, SCS1_N, SCS3_N, and SCS4_N and transmit them to the multiple switching elements S1_P, S3_P, S4_P, S1_N, S3_N, and S4_N. Of the multiple switching control signals SCS1_P to SCS4_P, SCS1_N to SCS4_N, SCS1_2, SCS1_3, SCS1_4, SCS2_3, SCS2_4, and SCS3_4, the remaining signals, excluding the on-level switching control signals SCS1_P, SCS3_P, SCS4_P, SCS1_N, SCS3_N, and SCS4_N, may be at off level. Hereinafter, for convenience of explanation, it is assumed that the switching control signals SCS1_P to SCS4_P, SCS1_N to SCS4_N, SCS1_2, SCS1_3, SCS1_4, SCS2_3, SCS2_4 and SCS3_4 are at the off level except for those explicitly indicated as being at the on level.

[0080] In FIG. 1 , when the plurality of relays 321 and 322 are turned on and the second driving device 22 is connected to the battery device 100, the BMS 200 may determine the voltage across P100+ and P100− of the battery device 100 as the second voltage V2. This is because the second voltage V2 corresponds to a power supply level required for operation of the second driving device 22. Since the voltage across each of two series groups connected in series among the plurality of battery packs 101 to 104 corresponds to the second voltage V1, the BMS 200 may determine at least one series group among the plurality of battery packs 101 to 104 to connect to both ends P100+ and P100− of the battery device 100. If there are two or more series groups, the BMS 200 may control two or more series groups to be connected in parallel.

[0081] Hereinafter, with reference to FIG. 3, a switching control operation in which the BMS 200 causes both ends P100+ and P100- of the battery device 100 to correspond to the first voltage V1 will be described.

[0082] FIG. 3 is an example of a battery system including multiple series groups of FIG.

[0083] The BMS 200 may determine at least one series group among the plurality of battery packs 101-104 to be connected to both ends P100+, P100- of the battery device 100 based on the pack voltages of each of the plurality of battery packs 101-104. The BMS 200 may pre-store a second reference voltage range, which is a normal range of the voltages across P100+, P100- of the battery device 100, corresponding to the second voltage. The BMS 200 may determine at least one series group in which the voltage across P100+, P100- of the battery device 100 falls within the second reference voltage range.

[0084] The BMS 200 may connect one series group to both ends P100+ and P100- of the battery device 100, or may connect two or more series groups in parallel.

[0085] Although the number of battery packs belonging to the series group has been described as two in this specification, the present invention is not limited to this. The BMS 200 may determine the number of battery packs belonging to the series group to correspond to the value obtained by dividing the second voltage V2 by the first voltage V1.

[0086] The BMS 200 may turn on a switching element connected between two battery packs belonging to a series group among the plurality of series switching elements S1_2, S1_3, S1_4, S2_3, S2_4, and S3_4, and turn off the remaining switching elements. The BMS 200 may turn on a switching element connected to a positive terminal P100+ of the battery device 100 among the plurality of positive switching elements S1_P to S4_P, and turn off the remaining switching elements. The BMS 200 may turn on a switching element connected to a negative terminal P100 of the battery device 100 among the plurality of negative switching elements S1_N to S4_N, and turn off the remaining switching elements.

[0087] The BMS 200 may determine the battery packs that belong to each of at least one series group to perform a switching control operation so that the voltages across P100+ and P100− of the battery device 100 correspond to the second voltage V2.

[0088] In the following description, it is assumed that the pack voltage of battery pack 101 is 360V, the pack voltage of battery pack 102 is 370V, the pack voltage of battery pack 103 is 380V, and the pack voltage of battery pack 104 is 390V.

[0089] The BMS 200 may derive the voltage across each of the at least one series group by taking into account the pack voltages of the battery packs belonging to each of the at least one series group.

[0090] If there are two or more series groups, the BMS 200 must determine a series group in which the voltage difference between the voltage across one of the two or more series groups and the voltage across the other of the two or more series groups is equal to or less than a predetermined threshold value, which may be 20 V, for example.

[0091] If the voltage difference between two or more series groups is large, an inrush current may occur during operation when the battery device 100 is connected to the first driving device 21 or the second driving device 22. This is because the occurrence of an inrush current may cause shock to the multiple battery packs 101 to 104 or components within the battery system 1.

[0092] Taking into consideration the pack voltages of each of the multiple battery packs 101 to 104, the BMS 200 may determine battery packs 101 and 104 as a first series group, and battery packs 102 and 103 as a second series group. The voltage across both ends of the first series group is V = 360 + 390 = 750 (V). The voltage across both ends of the second series group is V = 370 + 380 = 750 (V).

[0093] The BMS 200 may connect a first series group including battery pack 101 and battery pack 104 and a second series group including battery pack 102 and battery pack 103 among the plurality of battery packs 101 to 104 to both ends P100+ and P100- of the battery device 100.

[0094] The BMS 200 may generate an on-level switch control signal SCS1_4 and transmit it to the switching element S1_4 to serially connect the battery packs 101 and 104 belonging to the first series group. The BMS 200 may generate an on-level switch control signal SCS2_3 and transmit it to the switching element S2_3 to serially connect the battery packs 102 and 103 belonging to the second series group. Of the multiple switching control signals SCS1_2, SCS1_3, SCS1_4, SCS2_3, SCS2_4, and SCS3_4, the remaining switching control signals excluding the switch control signal SCS1_4 and the switch control signal SCS2_3 may be at an off level.

[0095] The BMS 200 may generate switch control signals SCS1_P and SCS2_P at an on level and transmit them to the switching elements S1_P and S2_P to connect the positive terminals of the first and second series groups to the positive terminal P100+ of the battery device 100. The BMS 200 may generate switch control signals SCS3_N and SCS4_N at an on level and transmit them to the switching elements S3_N and S4_N to connect the negative terminals of the first and second series groups to the negative terminal P100 of the battery device 100. Of the multiple switching control signals SCS1_P to SCS4_P, the remaining switching control signals excluding the switch control signals SCS1_P and SCS2_P may be at an off level. Of the multiple switching control signals SCS1_N to SCS4_N, the remaining switching control signals excluding the switch control signals SCS3_N and SCS4_N may be at an off level.

[0096] Referring to FIG. 3, according to a switching control operation, a first series group (a group in which battery pack 101 and battery pack 104 are connected in series) and a second series group (a group in which battery pack 102 and battery pack 103 are connected in series) may be connected in parallel to both ends P100+, P100- of the battery device 100.

[0097] The voltage across the first and second series groups may correspond to the voltage level of the second voltage V2 required for operation of the second driver 22.

[0098] FIG. 4 is a flowchart of a method for controlling connection between battery packs according to an embodiment.

[0099] Hereinafter, in regard to the operation of the BMS 200, explanations that overlap with the above explanation may be omitted.

[0100] The battery system 1 may be connected to an external system of the first driving device 21 or the second driving device 22 (S100). The BMS 200 may connect the battery device 100 to the first driving device 21 or the second driving device 22 via a plurality of relays 311, 312, 321, and 322. The BMS 200 may transmit on-level relay control signals RCS11 and RCS12 to the relays 311 and 312 to connect the battery device 100 to the first driving device 21 via terminals P1+ and P1−. Alternatively, the BMS 200 may transmit on-level relay control signals RCS21 and RCS22 to the relays 321 and 322 to connect the battery device 100 to the second driving device 22 via terminals P2+ and P2−.

[0101] The BMS 200 may determine whether the voltage across both ends P100+ and P100− of the battery device 100 is the first voltage V1 or the second voltage V2 (S200).

[0102] If the first drive device 21 or the second drive device 22 is a power conversion device connected to a charger, the BMS 200 may determine the voltage across both ends P100+, P100- of the battery device 100 depending on which of the first terminals P1+, P1- and the second terminals P2+, P2- to which the drive device is connected, and if the first drive device 21 or the second drive device 22 is a load, based on information received from the ECU 3.

[0103] In step S200, if the voltage across both ends P100+, P100- of the battery device 100 is the first voltage V1, the BMS 200 may connect one or more battery packs among the plurality of battery packs 101-104 in parallel to both ends P100+, P100- of the battery device 100 (S300). The BMS 200 may determine at least one battery pack to connect to both ends P100+, P100- of the battery device 100 based on the pack voltages of each of the plurality of battery packs 101-104.

[0104] Following step S300, the BMS200 may perform a switching control operation on a switch corresponding to at least one battery pack that has been determined to be connected to both ends P100+, P100- of the battery device 100 (S400). In the example of FIG. 2, the BMS200 may generate on-level switching control signals SCS1_P, SCS3_P, SCS4_P, SCS1_N, SCS3_N, and SCS4_N and transmit them to multiple switching elements S1_P, S3_P, S4_P, S1_N, S3_N, and S4_N.

[0105] In step S200, if the voltage across both ends P100+, P100- of the battery device 100 is the second voltage V2, the BMS 200 may determine at least one series group to be connected to both ends P100+, P100- of the battery device 100 (S500).

[0106] The BMS 200 may determine which battery packs belong to each of at least one series group of the battery packs 101 to 104 based on the pack voltages of each of the battery packs 101 to 104. When there are two or more series groups, the BMS 200 may determine which battery packs belong to each of the series groups so that the voltage difference between the voltages across the two or more series groups is equal to or less than a predetermined threshold.

[0107] Following step S500, the BMS 200 may perform a switching control operation (S600) on the switches corresponding to at least one series group determined to be connected to both ends P100+, P100− of the battery device 100. In the example of Fig. 3, the BMS 200 may generate on-level switching control signals SCS1_4, SCS2_3, SCS1_P, SCS2_P, SCS4_N, and SCS3_N and transmit them to multiple switching elements S1_4, S2_3, S1_P, S2_P, S3_N, and S4_N.

[0108] According to one embodiment, the BMS 200 may adjust the voltages across P100+ and P100− of the battery device 100 to a voltage level corresponding to the first voltage V1 or a voltage level corresponding to the second voltage V2. When two or more battery packs among the plurality of battery packs 101 to 104 are connected in series, the BMS 200 may determine which battery packs belong to the plurality of series groups so that the voltage difference between the voltages across the plurality of series groups is equal to or less than a predetermined threshold.

[0109] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the claims below also fall within the scope of the present invention.

Claims

1. a battery device including a plurality of battery packs; first and second terminals coupled to opposite ends of the battery device; and a BMS that derives a plurality of pack voltages for the plurality of battery packs based on a plurality of voltage measurement signals received from the plurality of battery packs, determines a voltage across the battery device as a first voltage or a second voltage depending on which of the first and second terminals is connected to a driving device, determines whether to connect the plurality of battery packs in parallel or in series based on the voltage across the battery device, and, if the plurality of battery packs are connected in series, determines which of the plurality of battery packs to connect in series based on the plurality of pack voltages; Battery system including.

2. The BMS communicates with an ECU via CAN and receives information indicating a discharge level of the battery device by either the first voltage or the second voltage from the ECU. The battery system of claim 1 .

3. When a first driving device driven at a voltage level of the first voltage is connected to the first terminal, or when information indicating a discharge level of the battery device as the first voltage is received from the ECU, The BMS includes: determining a voltage across the battery device as the first voltage, and connecting both ends of at least one battery pack among the plurality of battery packs to both ends of the battery device; The battery system of claim 2 .

4. When a second driving device driven at a voltage level of the second voltage is connected to the second terminal, or when information indicating a discharge level of the battery device as the second voltage is received from the ECU, The BMS includes: determining a voltage across the battery device as the second voltage, determining at least one series group including two or more battery packs connected in series among the plurality of battery packs, and connecting both ends of the at least one series group to both ends of the battery device; The battery system of claim 2 .

5. The BMS includes: When the number of the at least one series group is two or more, determining the two or more series groups such that a difference between a sum of a plurality of first pack voltages for a plurality of first battery packs belonging to a first series group among the two or more series groups and a sum of a plurality of second pack voltages for a plurality of second battery packs belonging to a second series group among the two or more series groups is equal to or less than a predetermined threshold; The battery system of claim 4.

6. The BMS includes: generating a switch control signal that connects the battery packs belonging to each of the two or more series groups in series, connects the positive terminal of each of the two or more series groups to the positive terminal of the battery device, and connects the negative terminal of each of the two or more series groups to the negative terminal of the battery device; The battery system of claim 5 .

7. A step in which the BMS connects a battery device including a plurality of battery packs to an external system via either a first terminal or a second terminal connected to both ends of the battery device; determining, by the BMS, a voltage across the battery device as a first voltage or a second voltage according to which of the first and second terminals is connected to a driving device; the BMS deriving a plurality of pack voltages for the plurality of battery packs based on a plurality of voltage measurement signals received from the plurality of battery packs; determining whether to connect the plurality of battery packs in parallel or in series based on the voltage across the battery device; and When the plurality of battery packs are connected in series, determining which battery packs to connect in series among the plurality of battery packs based on the plurality of pack voltages. A method for controlling connection between battery packs, including:

8. The BMS further includes a step of communicating with an ECU via CAN and receiving information indicating a discharge level of the battery device by either the first voltage or the second voltage from the ECU. The method for controlling connection between battery packs according to claim 7.

9. When a first driving device driven at a voltage level of the first voltage is connected to the first terminal, or when information indicating a discharge level of the battery device as the first voltage is received from the ECU, determining a voltage across the battery device as the first voltage; and further comprising the step of connecting opposite ends of at least one battery pack of the plurality of battery packs to opposite ends of the battery device. The method for controlling connection between battery packs according to claim 8.

10. When a second driving device driven at a voltage level of the second voltage is connected to the second terminal, or when information indicating a discharge level of the battery device as the second voltage is received from the ECU, determining a voltage across the battery device as the second voltage; determining at least one series group including two or more battery packs connected in series among the plurality of battery packs; and further comprising the step of connecting both ends of the at least one series group to both ends of the battery device. The method for controlling connection between battery packs according to claim 8.

11. When the number of the at least one series group is two or more, The step of determining at least one series group comprises: determining the two or more series groups such that a difference between a sum of a plurality of first pack voltages for a plurality of first battery packs belonging to a first series group among the two or more series groups and a sum of a plurality of second pack voltages for a plurality of second battery packs belonging to a second series group among the two or more series groups is equal to or less than a predetermined threshold; The method for controlling connection between battery packs according to claim 10.

12. The BMS includes: further comprising generating a switch control signal to serially connect the battery packs belonging to each of the two or more series groups, connect a positive terminal of each of the two or more series groups to a positive terminal of the battery device, and connect a negative terminal of each of the two or more series groups to a negative terminal of the battery device. The method for controlling connection between battery packs according to claim 11.

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